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  • apoptosis  (72)
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  • Springer  (83)
  • Elsevier  (52)
  • Institute of Physics
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  • 1
    Electronic Resource
    Electronic Resource
    Evidence for the induction of apoptosis by endosulfan in a human T-cell leukemic line (2000)
    Springer
    Molecular and cellular biochemistry 205 (2000), S. 53-66 
    Details
    ISSN: 1573-4919
    Keywords: endosulfan ; cytotoxicity ; mitochondria ; apoptosis ; Jurkat cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Several organochlorinated pesticides including DDT, PCBs and dieldrin have been reported to cause immune suppression and increase susceptibility to infection in animals. Often this manifestation is accompanied by atrophy of major lymphoid organs. It has been suggested that increased apoptotic cell death leading to altered T-B cell ratios, and loss of regulatory cells in critical numbers leads to perturbations in immune function. The major objective of our study was to define the mechanism by which endosulfan, an organochlorinated pesticide, induces human T-cell death using Jurkat, a human T-cell leukemic cell line, as an in vitro model. We exposed Jurkat cells to varying concentrations of endosulfan for 0-48 h and analyzed biochemical and molecular features characteristic of T-cell apoptosis. Endosulfan lowered cell viability and inhibited cell growth in a dose- and time-dependent manner. DAPI staining was used to enumerate apoptotic cells and we observed that endosulfan at 10-200 μM induced a significant percentage of cells to undergo apoptotic cell death. At 48 h, more than 90% cells were apoptotic with 50 μM of endosulfan. We confirmed these observations using both DNA fragmentation and annexin-V binding assays. It is now widely being accepted that mitochondria undergo major changes early during the apoptotic process. We examined mitochondrial transmembrane potential (ΔΨm) in endosulfan treated cells to understand the role of the mitochondria in T-cell apoptosis. Within 30 min of chemical exposure, a significant percentage of cells exhibited a decreased incorporation of DiOC6(3), a cationic lipophilic dye into mitochondria indicating the disruption of ΔΨm. This drop in ΔΨm was both dose- and time-dependent and correlated well with other parameters of apoptosis. We also examined whether this occurred by the down regulation of bcl-2 protein expression that is likely to increase the susceptibility of Jurkat cells to endosulfan toxicity. Paradoxically, the intracellular expression of bcl-2 protein was elevated in a dose dependent manner suggesting endosulfan-induced apoptosis occurred by a non-bcl-2 pathway. Based on these data, as well as those reported elsewhere, we propose the following sequence of events to account for T-cell apoptosis induced by endosulfan: uncoupling of oxidative phosphorylation → excess ROS production → GSH depletion → oxidative stress → disruption of ΔΨm → release of cytochrome C and other apoptosis related proteins to cytosol → apoptosis. This study reports for the first time that endosulfan can induce apoptosis in a human T-cell leukemic cell line which may have direct relevance to loss of T cells and thymocytes in vivo. Furthermore, our data strongly support a role of mitochondrial dysfunction and oxidative stress in endosulfan toxicity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007080910396
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  • 2
    Electronic Resource
    Electronic Resource
    Effect of regulated expression of the fragile histidine traid gene on cell cycle and proliferation (2000)
    Springer
    Molecular and cellular biochemistry 204 (2000), S. 83-88 
    Details
    ISSN: 1573-4919
    Keywords: FHIT ; cell cycle ; ecdysone ; tumor suppressor ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The mechanism of tumor suppressor action of the fragile histidine triad (FHIT) gene is unknown. Disruption of cell cycle regulation leads to the tumor formation and many tumor suppressor genes suppress tumorigenesis through their effect on cell cycle regulation. We examined the expression of FHIT during the cell cycle, and determined whether overexpression of FHIT affects cell cycle kinetics and apoptosis. The FHIT cDNA was cloned into the ecdysone-inducible expression vector in both the sense and antisense orientations. Overexpression of the sense or antisense construct did not affect cell proliferation, cell cycle distribution or apoptosis in human 293T cells. Analysis of the FHIT expression in 293T cells collected at various cell cycle phases showed that the expression of FHIT is not under cell cycle regulation. These results indicate that the tumor suppressor activity of the FHIT gene may be independent of an effect on the cell cycle and apoptosis mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007068823848
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  • 3
    Electronic Resource
    Electronic Resource
    Regulation of tumor growth and metastasis of human melanoma by the CREB transcription factor family (2000)
    Springer
    Molecular and cellular biochemistry 212 (2000), S. 19-28 
    Details
    ISSN: 1573-4919
    Keywords: melanoma ; transcription factors ; CREB ; invasion ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The purpose of this study was to determine the role of CREB and its associated proteins in melanoma progression. We used MeWo human melanoma cells transfected with a dominant negative construct of CREB, KCREB. KCREB has a mutation in its DNA-binding domain and can not bind the CRE element. Expression of KCREB yields proper heterodimerization with CREB and its associated proteins, but the proteins associated with KCREB do not confer the same degree of transcriptional activity as they would in the case of wild-type CREB. Here, we demonstrate that expression of KCREB in MeWo melanoma cells leads to a decrease in their tumorigenicity and metastatic potential in nude mice. We identified two mechanisms that explain at least partially this effect of KCREB. The first, is one in which CREB and its associated proteins play an essential role in invasion. We showed that the invasive properties of KCREB-transfected MeWo cells were reduced due to the downregulation of the CRE-dependent expression of the type IV collagenase MMP-2 and the adhesion molecule MCAM/MUC18. In the second mechanism, CREB and its associated proteins act as survival factors for human melanoma cells. Here we demonstrated that expression of KCREB in MeWo cells rendered them susceptible to apoptosis induced by thapsigargin, which in turn increased the intracellular level of Ca2+. Thapsigargin induced CREB and ATF-1 phosphorylation and activated CRE-dependent transcription in MeWo cells. Collectively, our data demonstrate that CREB and its associated proteins play an important role in tumor growth and metastasis of human melanoma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007128101751
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  • 4
    Electronic Resource
    Electronic Resource
    Increased T-type Ca2+ channel activity as a determinant of cellular toxicity in neuronal cell lines expressing polyglutamine-expanded human androgen receptors (2000)
    Springer
    Molecular and cellular biochemistry 203 (2000), S. 23-31 
    Details
    ISSN: 1573-4919
    Keywords: T-type Ca2+ channel ; polyglutamine-expanded androgen receptor ; CAG trinucleotide repeats ; spinobulbar muscular atrophy ; apoptosis ; motorneuron ; cell lines ; neuroblastoma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract We have analyzed Ca2+ currents in two neuroblastoma-motor neuron hybrid cell lines that expressed normal or glutamine-expanded human androgen receptors (polyGln-expanded AR) either transiently or stably. The cell lines express a unique, low-threshold, transient type of Ca2+ current that is not affected by L-type Ca2+ channel blocker (PN 200-110), N-type Ca2+ channel blocker (ω-conotoxin GVIA) or P-type Ca2+ channel blocker (Agatoxin IVA) but is blocked by either Cd2+ or Ni2+. This pharmacological profile most closely resembles that of T-type Ca2+ channels [1-3]. Exposure to androgen had no effect on control cell lines or cells transfected with normal AR but significantly changed the steady-state activation in cells transfected with expanded AR. The observed negative shift in steady-state activation results in a large increase in the T-type Ca2+ channel window current. We suggest that Ca2+ overload due to abnormal voltage-dependence of transient Ca2+ channel activation may contribute to motor neuron toxicity in spinobulbar muscular atrophy (SBMA). This hypothesis is supported by the additional finding that, at concentrations that selectively block T-type Ca2+ channel currents, Ni2+ significantly reduced cell death in cell lines transfected with polyGln-expanded AR.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007010020228
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  • 5
    Electronic Resource
    Electronic Resource
    Synergistic effects of 8-Cl-cAMP and retinoic acids in the inhibition of growth and induction of apoptosis in ovarian cancer cells: Induction of retinoic acid receptor β (2000)
    Springer
    Molecular and cellular biochemistry 204 (2000), S. 1-9 
    Details
    ISSN: 1573-4919
    Keywords: retinoic acid ; RARβ ; protein kinase A ; apoptosis ; caspase
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Both cAMP and retinoids play a role in cell differentiation and the control of cell growth. A site-selective cAMP analog, 8-Cl-cAMP and retinoic acid synergistically inhibit growth and induce apoptosis in certain cancer cells. In advanced or recurrent malignant diseases, retinoic acid (RA) is not effective even at doses that are toxic to the host. The objective of our present study was to examine the mechanism(s) of synergistic effects of retinoic acid (9-cis, 13-cis or all-trans RA) and 8-Cl-cAMP on apoptosis in human ovarian cancer NIH: OVCAR-3 and OVCAR-8 cells. RA induced growth inhibition and apoptosis in OVCAR-3 and OVCAR-8 cells. 8-Cl-cAMP acted synergistically with RA in inducing and activating retinoic acid receptor β (RARβ) which correlates with growth inhibition and apoptosis in both cell types. In addition, induction of apoptosis by RA plus 8-Cl-cAMP requires caspase-3 activation followed by cleavage of anti-poly(ADP-ribose) polymerase. Furthermore, mutations in CRE-related motif within the RARβ promoter resulted in loss of both transcriptional activation of RARβ and synergy between RA and 8-Cl-cAMP. RARβ expression appears to be associated with induction of apoptosis. Introduction of the RARβ gene into OVCAR-3 cells resulted in gain of RA sensitivity. Loss of RARβ expression, therefore, may contribute to the tumorigenicity of human ovarian cancer cells. Thus, combined treatment with RA and 8-Cl-cAMP may provide an effective means for inducing RARβ expression leading to apoptosis in ovarian cancer cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007074814676
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  • 6
    Electronic Resource
    Electronic Resource
    Transcriptional activation of p21WAF1by PTEN/MMAC1 tumr suppressor (2000)
    Springer
    Molecular and cellular biochemistry 203 (2000), S. 59-71 
    Details
    ISSN: 1573-4919
    Keywords: PTEN tumor suppressor ; cyclin-dependent kinase inhibitors ; apoptosis ; chemosensitivity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The recently discovered tumor suppressor gene PTEN has been found mutated in many types of advanced tumors. When introduced into tumor cells that lack the wild-type allele of the gene, PTEN was able to suppress the growth of these cells. Here, we have analyzed how PTEN might alter cell cycle-regulatory controls to achieve this growth-inhibitory effect. We found that overexpression of PTEN stimulates the synthesis of three inhibitors of cyclin-dependent kinases, p21WAF1, p27KIP1, and p57,KIP2. This effect is very specific, as the expression of other components of the cell cycle engine, various cyclins and cyclin-dependent kinases, is not affected. For p21WAF1 we show that this induction is due to the p53-independent transcriptional activation of its promoter. In addition, increased expression of PTEN rendered the cells more sensitive to apoptotic cell death. Therefore, our data suggest a two-fold mechanism of growth inhibition by PTEN: one that acts via the increased expression of CKIs such as p21WAF1, and another that augments the cellular propensity for apoptotic cell death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007024624967
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  • 7
    Electronic Resource
    Electronic Resource
    Unmodified calcium concentrations in tumour necrosis factor receptor subtype-mediated apoptotic cell death (2000)
    Springer
    Molecular and cellular biochemistry 211 (2000), S. 19-26 
    Details
    ISSN: 1573-4919
    Keywords: tumour necrosis factor ; receptors ; subtypes ; calcium ; apoptosis ; cancer
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Tumour necrosis factor-α (TNF) receptors mediate a variety of effects dependent on cell type. A role for Ca2+ in TNF-induced death remains uncertain. Here we investigated restricting intracellular/extracellular Ca2+ in HeLa epithelial carcinoma cells expressing low and high levels of p75TNFR receptor subtype and KYM-1 rhabdomyosarcoma cells, models of rapid TNF-induced apoptosis. Ca2+-chelators EGTA and BAPTA-AM as well as microsomal Ca2+-ATPase inhibitor thapsigargin, did not alter TNF-induced death. TNF was also unable to alter resting [Ca2+]i levels which remained 〈 200 nM even during times when these cells were undergoing apoptotic cell death. These findings indicate no role for modulated Ca2+ concentrations in TNF-induced apoptotic cell death.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007189911897
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  • 8
    Electronic Resource
    Electronic Resource
    Differential responses to Bcl-2 family genes to etoposide in chronic myeloid leukemia K562 cells (2000)
    Springer
    Molecular and cellular biochemistry 206 (2000), S. 43-50 
    Details
    ISSN: 1573-4919
    Keywords: etoposide ; Bcl-XL ; Bax ; apoptosis ; K562 cells
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Etoposide is a potent anticancer agent that is used to treat various tumors. We have investigated the dose-dependent effect of etoposide on apoptosis using chronic myeloid leukemia K562 cells treated with low (5 μM) or high (100 μM) concentrations of the drug. At a low concentration, etoposide induced little apoptosis at 24 h, while about 20% of the cells showed apoptosis morphologically at a high concentration. Processing of caspase-3 was slightly detected from 12 h and became obvious at 24 h with 100 μM etoposide. Caspase-3-like protease activity was detected at 24 h with a high concentration. Moreover, these changes were accompanied by cleavage of poly ADP ribose polymerase (PARP). Changes of the mRNA levels of most apoptosis-regulating genes were not prominent at both concentrations, except for the rapid induction of c-IAP-2/HIAP-1 and the down-regulation of Bcl-XL by 100 μM etoposide. The downregulation of Bcl-XL protein occurred from 6 h, while Bax protein conversely showed a slight increase from 6 h. Taken together, the present findings show that the dose-dependent apoptotic effect of etoposide is based on a change in the balance between Bcl-XL and Bax, which precedes the activation of caspase-3.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007056727876
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  • 9
    Electronic Resource
    Electronic Resource
    Glycochenodeoxycholic acid (GCDC) induced hepatocyte apoptosis is associated with early modulation of intracellular PKC activity (2000)
    Springer
    Molecular and cellular biochemistry 207 (2000), S. 19-27 
    Details
    ISSN: 1573-4919
    Keywords: PKC ; apoptosis ; bile acid ; hepatocyte
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The effect of GCDC-induced apoptosis on PKC activity and PKC's role in GCDC-induced hepatocyte apoptosis is unclear. The specific aims of this study were to determine if GCDC-induced apoptosis changed intracellular PKC activity and if modulation of PKC activity affected GCDC-induced hepatocyte apoptosis. Apoptosis was induced in isolated hepatocytes using GCDC. PKC activity was measured and specific PKC and calpain inhibitors were used to study the effects of PKC and calpain modulation on GCDC-induced apoptosis. After 4 h exposure, 50 μM GCDC induced apoptosis in 42% of hepatocytes. Intracellular PKC activity decreased to 44% of controls 2 h after exposure of hepatocytes to GCDC (p 〈 0.001). Pre-incubation of hepatocytes with the calpain protease inhibitor restored PKC activity in GCDC exposed hepatocytes to 91± 5% of control cells. Pre-incubation of hepatocytes with a calpain inhibitor decreased GCDC-induced apoptosis as did pre-incubation with the PKC activating phorbol ester, PMA. The combination of calpain inhibition and PMA further reduced GCDC-induced apoptosis but caused low level hepatic apoptosis. Inhibition of PKC with chelerythrine also substantially reduced GCDC-induced hepatocyte apoptosis. GCDC-induced apoptosis is associated with decreases in total cellular PKC activity, which appear to be dependent on intracellular calpain-like protease activity. The combination of protease inhibition and phorbol ester pretreatment preserved total cellular PKC activity and decreased GCDC-induced apoptosis but induced low level apoptosis in the absence of GCDC exposure. PKC inhibition also decreased GCDC-induced hepatocyte apoptosis highlighting the complex interactions of PKC and proteases during GCDC-induced apoptosis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007021710825
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  • 10
    Electronic Resource
    Electronic Resource
    Dexamethasone increases the incorporation of [3H] serine into phosphatidylserine and the activity of serine base exchange enzyme in mouse thymocytes: A possible relation between serine base exchange enzyme and apoptosis (2000)
    Springer
    Molecular and cellular biochemistry 211 (2000), S. 61-67 
    Details
    ISSN: 1573-4919
    Keywords: phosphatidylserine ; base exchange ; apoptosis ; thymocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract The exposure of phosphatidylserine toward the external surface of the membrane is a well-established event of programmed cell death. The possibility that an apoptotic stimulus influences the metabolism of this phospholipid could be relevant not only in relation to the previously mentioned event but also in relation to the capability of membrane phosphatidylserine to influence PKC activity. The present investigation demonstrates that treatment of mouse thymocytes with the apoptotic stimulus dexamethasone, enhances the incorporation of [3H]serine into phosphatidylserine. Cell treatment with dexamethasone also enhanced the activity of serine base exchange enzyme, assayed in thymocyte lysate. Both the effects were observed at periods of treatment preceding DNA fragmentation. The addition of unlabelled ethanolamine, together with [3H]serine to the medium containing dexamethasone-treated thymocytes lowered the radioactivity into phosphatidylserine. Serine base exchange enzyme activity was influenced by the procedure used to prepare thymocyte lysate and was lowered by the addition of fluoroaluminate, that is widely used as a G-protein activator. The increase of serine base exchange enzyme activity induced by dexamethasone treatment was observed independently by the procedure used to prepare cell lysate and by the presence or absence of fluoroaluminate.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007102531404
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  • 11
    Electronic Resource
    Electronic Resource
    Attenuation of macrophage apoptosis by the cAMP-signalling system (2000)
    Springer
    Molecular and cellular biochemistry 212 (2000), S. 35-43 
    Details
    ISSN: 1573-4919
    Keywords: cAMP ; CRE ; Cox-2 ; NO ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Abstract Previous studies revealed that expression and activation of cyclooxygenase-2 (Cox-2) conveyed a protective principle in murine macrophages, thus attenuating pro-apoptotic actions of chemotherapeutic agents or programmed cell death as a result of massive nitric oxide (NO) generation. Expression of Cox-2 was achieved by treatment of cells with lipopolysaccharide/interferon-γ or nontoxic doses of NO releasing agents. We reasoned E-type prostanoid formation, and in turn an intracellular cAMP increase as the underlying protective mechanism. To prove our hypothesis, we analyzed the effects of lipophilic cAMP-analogs on NO, cisplatin, or etoposide induced apoptosis in RAW 264.7 macrophages. Selected apoptotic parameters comprised DNA fragmentation (diphenylamine assay), annexin V staining of phosphatidylserine, caspase activity (quantitated by the cleavage of a fluorogenic caspase-3-like substrate Ac-DEVD-AMC), and mitochondrial membrane depolarisation (ΔΨ). Western blots detected accumulation of the tumor suppressor protein p53, relocation of cytochrome c to the cytosol, and expression of the anti-apoptotic protein Bcl-xL. Prestimulation with lipophilic cAMP-analogs attenuated apoptosis with the notion that cell death parameters were basically absent. To verify gene induction by cAMP in association with protection we established activation of cAMP response element binding protein (CREB) by gel-shift analysis and moreover, treated macrophages with oligonucleotides containing a cAMP-responsive element (CRE) in order to scavenge CREB. Decoy oligonucleotides, but not control oligonucleotides, attenuated cAMP-evoked protection and reestablished pro-apoptotic parameters. We conclude that gene induction by cAMP protects macrophages towards apoptosis that occurs as a result of excessive NO formation or addition of chemotherapeutica. Attenuating programmed cell death by the cAMP-signaling system may be found in association with Cox-2 expression and tumor formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007124203607
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  • 12
    Electronic Resource
    Electronic Resource
    Hydrogen peroxide-induced apoptosis in human hepatoma cells is mediated by CD95(APO-1/Fas) receptor/ligand system and may involve activation of wild-type p53 (2000)
    Springer
    Molecular biology reports 27 (2000), S. 1-11 
    Details
    ISSN: 1573-4978
    Keywords: apoptosis ; CD95 ; human hepatoma cell ; hydrogen peroxide ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Reactive oxygen species (ROS) play an important role in cell death induced by many different stimuli. Direct exposure of human hepatoma cell line SMMC-7221 to hydrogen peroxide (H2O2) can induce apoptosis characterized by morphological evidence and fragmentation of DNA assayed by terminal deoxynucleotidyl transferase assay (TUNEL assay). Analysis of flow cytometry indicated that H2O2 can decrease the level of CD95(APO-1/Fas), and it is confirmed that H2O2 can also activate the differential expression of some specific gene such as p53 by means of RT-PCR technique. The results indicated that CD95 signal transduction system may be involved in the H2O2-induced apoptosis, and can regulate some specific genes associated with apoptosis in transcription and translation levels such as p53.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007003229171
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  • 13
    Electronic Resource
    Electronic Resource
    Antisense Downregulation of the Apoptosis-related Bcl-2 and Bcl-xL Proteins: A New Approach to Cancer Therapy (2000)
    Springer
    Molecular biology 34 (2000), S. 875-887 
    Details
    ISSN: 1608-3245
    Keywords: antisense oligonucleotides ; oncogenesis ; therapy of cancer ; apoptosis ; bcl family
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Members of the bcl-2 family genes are thought to be central regulators of apoptosis. Overexpression of antiapoptotic proteins, such as Bcl-2 and Bcl-xL, contributes not only to the development of cancer but also to its resistance against a wide variety of anticancer agents. Thus, downregulation of Bcl-2 and Bcl-xL can potentially be used to improve therapeutic approaches to advanced cancer. The use of antisense biotechnology to downregulate antiapoptotic bcl family members in diverse cancers in vitro and in vivo is reviewed. The effects and potential limitations of antisense strategies are also discussed in the context of a critical view of recent research in the field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026679826610
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  • 14
    Electronic Resource
    Electronic Resource
    Induction of apoptosis in cultured cells by extracts from shiitake (Lentinula edodes) mycelial culture broth (2000)
    Springer
    Mycoscience 41 (2000), S. 623-631 
    Details
    ISSN: 1618-2545
    Keywords: apoptosis ; caspase-3 ; E2F factor ; Lentinula edodes ; mycelial culture broth
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Extracts fromshiitake (Lentinula edodes) mycelial culture broth, by an organic solvent ethyl acetate, inhibited the proliferation of cultured cells. At lower concentrations (1.25–15 μg/ml), this inhibition, measured by the MTT assay, was dose- and cell line-dependent. Inhibition of tumor cells, such as Caski, SiHa, HeLa, HP-1 and A375, byL. edodes-436 extracts was stronger than inhibition of normal cells (3T3). At 20 μg/ml, the extracts induced changes in cell shape, DNA-fragmentation and the activation of caspase-3. The extracts also inhibited the binding of E2F protein to its promoter. The results suggest that extracts ofL. edodes culture broth contain substances that have the ability to induce apoptosis in the cultured cells.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02460929
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  • 15
    Electronic Resource
    Electronic Resource
    Prolongation of murine hybridoma cell survival in stationary batch culture by Bcl-xL expression (2000)
    Springer
    Cytotechnology 34 (2000), S. 131-139 
    Details
    ISSN: 1573-0778
    Keywords: apoptosis ; bcl-xL ; cell growth ; cell viability ; hybridoma ; myeloma
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract While the ectopic expression of the anti-apoptoticprotein Bcl-2 has been shown to significantly increaseboth cell viability and antibody production in batchculture, some cell lines are refractory to thesemanipulations. For example, the NS/O and theP3x63Ag8.653 murine myelomas, which express highendogenous levels of the Bcl-2 homologue Bcl-xL, areboth resistant to the anti-apoptotic effect of Bcl-2.This indicates that, in these cells, Bcl-2 and Bcl-xLmay be functionally redundant. In order to define therole which Bcl-xL plays in hybridoma cultures, we usedthe Sp2/0-Ag14 cell line. This murine hybridomaexpresses low levels of Bcl-xL and is highly sensitiveto apoptosis induction by cycloheximide (CHX) and byamino acid depletion. Bcl-xL-transfected Sp2/0-Ag14cells were more resistant than the wild type and theplasmid-containing cells to apoptosis induced by CHXand by glutamine depletion. Moreover, when compared tothe vector-transfected control, Bcl-xL-Sp2/0 cellsexhibited a substantial increase in viability instationary batch culture. Interestingly, Sp2/0-Ag14cells overexpressing Bcl-xL showed a growth behaviourthat was similar to the parent myeloma cell lineP3x63Ag8.653. Our results suggest that Bcl-xLexpression levels are sufficient to account for therelative robustness of some hybridoma cell lines instationary batch cultures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008186302600
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  • 16
    Electronic Resource
    Electronic Resource
    Establishment of an apoptosis-suppressible,cell-cycle arrestable cell line and its applicationfor enhancing protein production of serum-free or-supplemented culture (2000)
    Springer
    Cytotechnology 32 (2000), S. 125-134 
    Details
    ISSN: 1573-0778
    Keywords: antisense ; apoptosis ; cell cycle ; c-jun ; protein production
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Expression of c-jun gene induces apoptosis ofcells cultured in serum-free medium. It also promotescell-cycling in serum-containing medium, leading cellsto die by overgrowth. Previously, we established anapoptosis-suppressible, cell-cycle arrestable cellline, c-jun AS, by transfecting Friend murineerythroleukemia (F-MEL) cells with adexamethasone-inducible antisense c-jun gene.Induction of the antisense c-jun transcriptionwith dexamethasone suppressed c-jun expression.As a result, c-jun AS cells survived inserum-free medium containing dexamethasone for a longtime, while F-MEL cells died quickly in the presenceor absence of dexamethasone. In serum-containingmedium, the growth of c-jun AS cells was viablyblocked by inducing antisense c-juntranscription, and the cells survived at thenon-growth state avoiding overgrowth. In the presentstudy, protein productivity of c-jun AS cellswas examined in comparison with that of wild typeF-MEL cells. C-jun AS and F-MEL cells werefurther transfected with a vector for expressingalkaline phosphatase as a protein to be produced, andnamed c-jun AS-SEAP and F-MEL-SEAP cells,respectively. In the serum-free medium withdexamethasone, c-jun AS-SEAP cells produced theprotein for up to 6 days, while F-MEL-SEAP cellsstopped production on day 3 due to cell death causedby serum deprivation. In the serum-containing mediumwith dexamethasone, c-jun AS-SEAP cells wereviably arrested in the cell cycle, and cell death dueto overgrowth was avoided. As the result, they couldproduce the protein for up to 18 days, whileF-MEL-SEAP cells stopped production within 7 days dueto cell death caused by overgrowth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1008149218360
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  • 17
    Electronic Resource
    Electronic Resource
    Decrease in cell surface sialic acid in etoposide-treated Jurkat cells and the role of cell surface sialidase (2000)
    Springer
    Glycoconjugate journal 17 (2000), S. 301-306 
    Details
    ISSN: 1573-4986
    Keywords: sialidase ; sialyltransferase ; apoptosis ; Jurkat cells ; etoposide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The present study investigated the mechanism underlying alterations of cell surface sugar chains of Jurkat cells by inducing apoptosis with etoposide, an inhibitor of topoisomerase II. Within 3[emsp4 ]h of etoposide treatment, flowcytometric analysis revealed a decrease in Maackia amurensis agglutinin recognized α2,3-linked sialic acid moieties and an increase in Ricinus communis agglutinin recognized galactose. The results suggested that asialo-sugar chains on glycoconjugates were rapidly induced on the etoposide-treated cell surface. To clarify the desialylation mechanism, we studied α2,3-sialyltransferase mRNA expression and the activity of sialidase on the cell surface during etoposide-induced apoptosis. The expression of hST3Gal III and hST3Gal IV mRNAs were down-regulated and sialidase activity on the cell surface increased threefold within 2[emsp4 ]h of etoposide treatment. Moreover, the decrease in α2,3-linked sialic acid levels was significantly suppressed in the presence of 2,3-dehydro-2-deoxy-N-acetylneuraminic acid, an inhibitor of sialidase. These results suggested that activation or exposure of sialidase on the cell surface was induced by etoposide treatment and was the main cause of the decrease in sialic acids.
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    URL: http://dx.doi.org/10.1023/A:1007165403771
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    Ultrastructural Observations and DNA Degradation Analysis of Pepper Leaves Undergoing a Hypersensitive Reaction to Xanthomonas campestris pv. Vesicatoria (2000)
    Springer
    European journal of plant pathology 106 (2000), S. 423-431 
    Details
    ISSN: 1573-8469
    Keywords: apoptosis ; bacteria ; chromatin condensation ; DNA degradation analysis ; plant ; programmed cell death
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Ultrastructural details of the hypersensitive reaction induced by infiltration with avirulent race 2 Xanthomonas campestris pv. vesicatoria in pepper ‘Early Calwonder-10R’ leaves (incompatible interaction) are reported. Affected cells displayed plasmalemma undulations and disruption, lysis of the chloroplast membrane, degeneration of other organelles, general cytoplasm disorganisation and, often, protoplast shrinkage. The nuclei contained large masses of electron-dense material, apparently formed by chromatin aggregation. In many cases a single chromatin-like layer was deposited on the inner side of the nuclear envelope leaving a finely granular matrix in the centre of the nucleus; the nucleolus usually disappeared. The nuclear envelope was sometimes ruptured and the internal matrix leaked into the cytoplasm. The content of many affected cells eventually coagulated and became very electron-dense. The walls often collapsed. All these alterations were especially visible in spongy mesophyll cells at sites where bacteria occurred in the intercellular spaces. Although some of the nuclear and cytoplasmic alterations recall certain aspects of apoptotic cell death, molecular determinations did not reveal any DNA degradation in hypersensitively reacting tissues. The first cell alterations in leaves infected with the virulent bacterial race 1 (compatible interaction) were observed only 27 h after inoculation, when the cytoplasm of some cells showed limited internal disorganisation and plasmolysis at sites where bacterial colonies developed.
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    URL: http://dx.doi.org/10.1023/A:1008773321809
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    Minireview: Apoptosis as seen through a lens (2000)
    Springer
    Apoptosis 5 (2000), S. 203-209 
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    ISSN: 1573-675X
    Keywords: apoptosis ; lens development ; organelle loss ; denucleation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The lens represents an ideal model system for studying many of the cellular and molecular events of differentiation. It is composed of two ectodermally-derived cell types: the lens epithelial cells and the lens fibre cells, which are derived from the lens epithelial cells by differentiation. Programmed removal of nuclei and other organelles from the lens fibre cells ensures that an optically clear structure is created, while the morphology of the degenerating nuclei is similar to that observed during apoptosis and is accompanied by DNA fragmentation. These observations suggest the existence of biochemical parallels between the process of lens fibre cell organelle loss and classical apoptosis. For example, proteins encoded by the bcl-2 and caspase gene families are expressed in developing lenses and nuclear degeneration in lens fibre cells can be inhibited in vivo by overexpression of bcl-2 and in vitro by incubation of differentiating lens epithelial cell cultures with caspase inhibitors. Thus, the developing lens may represent a particularly useful model system for researchers interested in apoptosis. In this review, the recent literature pertaining to lens fibre cell organelle loss and its relationship to apoptosis is reviewed and possible future research directions are suggested.
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    URL: http://dx.doi.org/10.1023/A:1009653326511
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    The Daxx enigma (2000)
    Springer
    Apoptosis 5 (2000), S. 217-220 
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    ISSN: 1573-675X
    Keywords: Daxx ; apoptosis ; Fas ; PML ; ND10
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Several reports describing Daxx and its putative role have emerged without a unifying theme. While Daxx has been implicated in apoptosis, it remains unclear whether Daxx is pro- or anti-apoptotic, and whether its role in apoptosis is direct or indirect. Moreover, whether Daxx plays alternative or additional roles in regulating transcription, centromere binding or any number of other activities within the cell, is uncertain. The ability of Daxx to interact with a wide variety of molecules in yeast-interaction trap systems (Table 1) has allowed for this range of speculation. The fact that Daxx contains no significant homology to other known proteins has rendered its study all the more challenging.
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    URL: http://dx.doi.org/10.1023/A:1009696227420
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    Activation of MAD 2 checkprotein and persistence of cyclin B1/CDC 2 activity associate with paclitaxel-induced apoptosis in human nasopharyngeal carcinoma cells (2000)
    Springer
    Apoptosis 5 (2000), S. 235-241 
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    ISSN: 1573-675X
    Keywords: apoptosis ; cyclin B1/CDC 2 ; G2/M arrest ; MAD 2 ; paclitaxel
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Paclitaxel (Taxol™) is a microtubule-interfering agent that induced persistent and transient G2/M arrest before apoptosis in human nasopharyngeal carcinoma (NPC) cells at high and low concentrations, respectively. In this study, we intended to explore the underlying molecular events and found that cellular cyclin B1/CDC 2 kinase activity was increased and persisted for 〉6 h upon paclitaxel treatment both at high and low concentrations. Furthermore, activation of MAD 2 checkprotein could account for the loss of cyclin B1 ubiquitination and the persistence of cyclin B1/CDC 2 activation in the cases. To investigate the involvement of cyclin B1 and MAD 2 activation in paclitaxel-induced apoptosis, we introduced affinity-purified anti-cyclin B1 and MAD 2 antibodies into NPC cells by electroporation before the further paclitaxel treatment. The antibodies against cyclin B1 and MAD 2 indeed attenuated paclitaxel-induced cytotoxicity and DNA fragmentation. Our study suggests that activation of cyclin B1/CDC 2 and MAD 2 were the M-phase events required for paclitaxel-induced apoptosis in NPC cells. The dys-regulated cyclin B1/CDC 2 activation could enhance the prometaphase progression, but activation of MAD 2 rendered cells inable to exit from the metaphase. Under this circumstance, cells were probably going to “mitotic catastrophe” and ultimately, destined to apoptosis.
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    URL: http://dx.doi.org/10.1023/A:1009652412399
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    Induction of apoptosis by adenovirus E4orf4 protein (2000)
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    Apoptosis 5 (2000), S. 211-215 
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    ISSN: 1573-675X
    Keywords: adenovirus ; E4orf4 ; apoptosis ; protein phosphatase 2A (PP2A) ; caspases ; cancer ; gene therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Adenovirus E4orf4 protein is a multifunctional viral regulator that induces p53-independent apoptosis in transformed cells, but not in normal cells. E4orf4-induced apoptosis can occur without activation of known caspases, although E4orf4 induces caspase activity in some cell lines. The interaction of E4orf4 with a specific subpopulation of protein phosphatase 2A (PP2A) molecules that contain B subunits, but not with those that contain B′ subunits, is required for induction of apoptosis. This review suggests the potential use of E4orf4 in cancer therapy, and discusses whether E4orf4-induced apoptosis plays a role in the viral life cycle. Future research directions are also highlighted.
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    Apoptosis and the cell cycle in Xenopus: PMA and MPMA exposure of splenocytes (2000)
    Springer
    Apoptosis 5 (2000), S. 225-233 
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    ISSN: 1573-675X
    Keywords: Amphibia ; apoptosis ; cancer ; cell cycle
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Spontaneous and induced cancers are rare in non-isogeneic or inbred amphibians. Neoplastic cells become immortalized through loss of a normal capacity to die by apoptosis. Mature lymphocytes of mammals require activation and entry into the cell cycle in order to become susceptible to apoptosis. Whether Xenopus lymphocytes differ from mammalian lymphocytes in this regard is examined. In vitro exposure of PMA, or its analogue, MPMA, to adult splenocytes of Xenopus laevis was used to affect apoptosis. Flow cytometric analysis of FITC-Annexin V/propidium iodide (PI) fluorescence (apoptosis) and BrdU uptake (DNA synthesis) were assayed concurrently in the same lymphocyte population over time. Significant increases in apoptotic levels were induced throughout a 72 hour period in PMA-treated cells only. Lymphocytes were also separated by size for analysis. Several sub-populations of lymphocytes were identified, the most interesting of which was small and apoptotic within 4 hours, after PMA exposure. PMA-induced DNA synthesis did not become elevated until after 24 hours. “Direct” apoptosis, i.e. without cell cycle entry, was found only in these small, mature lymphocytes. Since small lymphocytes make up the vast majority of those being analyzed, “direct” apoptosis may be a determining mechanism in the resistance to neoplasia observed in Amphibia. Cells that die more readily are less likely to transform into neoplastic cells.
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    Caspase-3 activates endo-exonuclease: Further evidence for a role of the nuclease in apoptosis (2000)
    Springer
    Apoptosis 5 (2000), S. 243-254 
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    ISSN: 1573-675X
    Keywords: apoptosis ; caspase-3 ; nuclease ; endo-exonuclease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Single-strand DNase and poly rAase, activities characteristic of endo-exonuclease, were co-activated in nuclear fractions of HL-60 cells by caspase-3. Activation was accompanied by cleavages of large soluble polypeptides (130–185 kDa) and a 65 kDa inactive chromatin-associated polypeptide related to the endo-exonuclease of Neurospora crassa as detected on immunoblots. The major products seen in vitro were a 77 kDa soluble polypeptide and an active chromatin-associated 34 kDa polypeptide. When HL-60 cells were induced to undergo apoptosis by treating with 50 μM etoposide (VP-16) for 4 hours, 77 kDa and 40 kDa polypeptides accumulated in nuclear fractions. Chromatin DNA fragmentation activity was also activated in cytosol and nuclear extract either by pre-treating the cells in vivo with VP-16 or by treating the cytosol in vitro with caspase-3 or dATP and cytochrome c. Endo-exonuclease activated by caspase-3 in cytosol-derived fractions augmented chromatin DNA fragmentation activity in vitro. Endo-exonuclease is proposed to act in vivo in conjunction with the caspase-activated DNase (CAD) to degrade chromatin DNA during apoptosis of HL-60 cells.
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    Apoptosis, cross-presentation, and the fate of the antigen specific immune response (2000)
    Springer
    Apoptosis 5 (2000), S. 307-314 
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    ISSN: 1573-675X
    Keywords: apoptosis ; cancer ; cross-priming ; cross-tolerance ; dendritic cells ; T lymphocytes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Induction of cell death by apoptosis, also called programmed cell death, and clearance of apoptotic bodies by scavenger cells has long thought to be an efficient means to dispose of unwanted cells without causing inflammatory responses able to mediate specific reactions. However, a number of evidences have been accumulated suggesting that apoptotic cell death is implicated in the pathogenesis of systemic and organ specific autoimmune diseases. In addition, recognition and engulfement of apoptotic cells by professional antigen presenting cells, such as dendritic cells, and their interaction with effector immune cells have been recently described to result in apoptotic cell-derived antigen specific tolerance. This review will summarise the most recent findings on the immunogenic potential of cells undergoing programmed death.
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    URL: http://dx.doi.org/10.1023/A:1009671105696
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    Endothelial cell survival and apoptosis in the tumor vasculature (2000)
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    Apoptosis 5 (2000), S. 323-328 
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    ISSN: 1573-675X
    Keywords: Angiogenesis ; angiopoietins ; apoptosis ; integrins ; vascular endothelial growth factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Angiogenesis is essential for the growth and metastasis of solid tumors. The balance of endothelial cell (EC) proliferation and apoptosis is a major determinant in tumor angiogenesis. Recently, several studies demonstrated that numerous angiogenic factors not only induce angiogenesis but also function as EC survival factors. Vascular endothelial growth factor (VEGF), a potent angiogenic factor, is also an EC survival factor in embryonic vasculogenesis and tumor angiogenesis. VEGF activates specific intracellular survival pathways in ECs including Bcl-2, A1, IAP, Akt, and Erk. Integrins may function as EC survival factors by preventing anoikis by enhancing binding to the extracellular matrix. In addition, integrins may function in concert with VEGF to promote EC survival. Angiopoietin-1 (Ang-1) has recently been shown to stabilize EC networks by binding to the EC-specific tyrosine kinase receptor Tie-2. Pericytes also function as EC survival factors, by cell-cell contact, secretion of survival factors, or both. Targeting any of the above mechanisms for EC survival may provide novel antineoplastic strategies.
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    URL: http://dx.doi.org/10.1023/A:1009679307513
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    Induction of apoptosis in human cancer cells by TZT-1027, an antimicrotubule agent (2000)
    Springer
    Apoptosis 5 (2000), S. 345-353 
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    ISSN: 1573-675X
    Keywords: apoptosis ; antimicrotubule agent ; cell cycle ; dolastatin 10 ; TZT-1027
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract TZT-1027, a newly synthesized dolastatin 10 derivative, is a potent antitumor agent which inhibits microtubule polymerization and perturbs microtubule dynamics. In this report, we investigated whether TZT-1027 inhibited the growth of various human cancer cells, and the cell death caused by TZT-1027 was due to apoptosis. In addition, we elucidated the apoptosis machinery induced by treatment with TZT-1027. The 50% growth-inhibitory concentrations (IC50 values) of TZT-1027 on cancer cells derived from various sources were not more than 5.9 ng/ml. TZT-1027 showed superior cytotoxicity than any other antitumor agents. Next, we evaluated morphological nuclear change, namely, chromatin condensation and DNA fragmentation. We used three cancer cell lines derived from different types in view of having apoptosis related protein, human leukemia HL-60 (in the presence of both Caspase-3 and Bcl-2), human breast cancer MCF-7 (in the absence of Caspase-3), and human prostate cancer DU145 (in the absence of Bcl-2). TZT-1027 induced DNA fragmentation in the presence but not absence of Caspase-3. Nevertheless, apoptic chromatin condensation was observed in all cancer cells even if there was no Caspase-3. Furthermore, we examined whether TZT-1027, microtubule-disrupting agent, influenced cell cycle progression. Flow cytometric analysis revealed the cells treated with TZT-1027, and with the other antimicrotubule agents, to be arrested at the G2/M phase and subsequently to show fragmented DNA smaller than that of G1 phase cells. Moreover, we tested TZT-1027 for its ability to induce Bcl-2 phosphorylation in human cancer cell lines. TZT-1027 and other agents which interacted with microtubules induced Bcl-2 phosphorylation, whereas DNA-damaging agents did not. The present results suggested an association of the growth-inhibitory effect of TZT-1027 with the induction of apoptosis and indicated that the apoptosis induced by TZT-1027 was followed by G2/M arrest even if there was no Caspase-3 or Bcl-2.
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    Increased apoptosis and increased clonogenic survival of 12V-H-ras transformed rat fibroblasts in response to cisplatin (2000)
    Springer
    Apoptosis 5 (2000), S. 355-367 
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    ISSN: 1573-675X
    Keywords: apoptosis ; chemotherapy resistance ; clonogenicity ; ras
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Mutationally activated Ras is involved in tumor progression and likely also in drug resistance. Using survival, viability and apoptosis assays, we have here compared the cisplatin sensitivities of FR3T3 rat fibroblasts and a 12V-H-ras transformed subline (Ras2:3). Around 24 h after cisplatin treatment Ras2:3 cells showed higher apoptosis levels and lower viability than FR3T3. This increased sensitivity correlated with weaker cisplatin-induced activation of Jun N-terminal kinase (JNK). In contrast to apoptosis assays, colony formation assays showed that Ras2:3 were more resistant to cisplatin than were FR3T3. This was partly due to the increased cisplatin sensitivity of FR3T3 seeded at low densities, as required in colony formation assays. In addition, Ras2:3 cisplatin survivors had a higher relative proliferative capacity. Cell cycle analyses showed that FR3T3 cells initially responded with a dose-dependent G2 arrest, while Ras2:3 accumulated in S-phase. Experiments with an anti-apoptotic mutant of MEKK1 suggested that the apoptotic response of Ras2:3 cells is not specific to the S-phase fraction. In summary, the cisplatin response of ras-transformed fibroblasts is distinct from that of parental cells, in that they show increased apoptosis, a different cell cycle response and increased post-treatment proliferative capacity. The results illustrate the need to carefully consider methods and protocols for in vitro studies on chemotherapy sensitivity.
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    Role of reactive oxygen species (ROS) in apoptosis induction (2000)
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    Apoptosis 5 (2000), S. 415-418 
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    ISSN: 1573-675X
    Keywords: apoptosis ; death receptors ; inflammation ; reactive oxygen species (ROS)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Reactive oxygen species (ROS) and mitochondria play an important role in apoptosis induction under both physiologic and pathologic conditions. Interestingly, mitochondria are both source and target of ROS. Cytochrome c release from mitochondria, that triggers caspase activation, appears to be largely mediated by direct or indirect ROS action. On the other hand, ROS have also anti-apoptotic effects. This review focuses on the role of ROS in the regulation of apoptosis, especially in inflammatory cells.
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    CD95/CD95L interactions and their role in autoimmunity (2000)
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    Apoptosis 5 (2000), S. 419-424 
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    ISSN: 1573-675X
    Keywords: apoptosis ; diabetes ; Fas ; organ-specific auto-immunity ; thyroiditis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract CD95 (Fas/Apo-1) is a broadly expressed death receptor involved in a variety of physiological and pathological apoptotic processes. Since its discovery, defects in CD95/CD95L system have been proposed as major pathogenic factors responsible for impaired immunological tolerance to self antigens and autoimmunity. Later, analysis of altered sensitivity to CD95-induced apoptosis in cells targeted by the immune response has revealed an unexpected role for CD95 and CD95L in organ-specific autoimmunity. CD95 has been shown to be expressed and functional in virtually all cell types that are target of the organ-specific autoimmune response. Here we review some of the major findings concerning the role of CD95 in autoimmunity, in dysfunctions due to increased or decreased CD95-induced apoptosis.
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    Role of apoptosis in autoimmunity (2000)
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    Apoptosis 5 (2000), S. 443-449 
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    ISSN: 1573-675X
    Keywords: apoptosis ; autoimmunity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Apoptosis is a physiological form of cell death required to ensure that the rate of cell division is balanced by the rate of cell death in multicellular organisms. Dysregulation of apoptosis is associated with the pathogenesis of a wide array of diseases: cancer, neurodegeneration, autoimmunity, heart disease and others. In this review we collect arguments supporting a hypothesis of a dysregulated apoptosis leading to development of autoimmunity like systemic lupus erythematosus (SLE). This notion is supported by occurence of known autoantigens in apoptotic blebs, in vitro findings of an increased rate of apoptotic lymphoblasts despite optimal cytokine stimulation combined with a defective in vitro clearance of apoptotic bodies by SLE phagocytes. Moreover, we and others could generate histone-specific lymphocytic cell lines from cells after activation with autologous apoptotic material. These lymphocytes could stimulate autologous B-lymphocytes to produce of anti-dsDNA antibodies, a diagnostic hallmark for SLE. Finally, antibodies against phospholipids like phosphatidylserine are often associated with systemic autoimmunopathies like SLE and others. Phosphatidylserine is exposed on apoptotic cells as early sign of programmed cell death and serves as phagocyte recognition molecule for apoptotic cells. Formation of immune complexes and deposition in tissues might lead to organ damage and disease. This scenario will be discussed in this review in detail.
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    Apoptosis in Alzheimer's disease—an update (2000)
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    Apoptosis 5 (2000), S. 9-16 
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    ISSN: 1573-675X
    Keywords: Aging ; Alzheimer's disease ; amyloid precursor protein ; apoptosis ; Bcl-2 ; caspase ; presenilin ; transcription factor ; β amyloid.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Alzheimer's disease (AD) is the most common human neurodegenerative disorder characterized by the progressive deterioration of cognition and memory in association with the presence of senile plaques, neurofibrillary tangles, and massive loss of neurons. Most cases of AD are late-onset and sporadic, but in some cases the disease is inherited as an autosomal dominant trait. Four different genes, the amyloid precursor protein, apolipoprotein E, and presenilins 1 and 2 have been implicated in the etiology of familial AD. It is now generally accepted that massive neuronal death due to apoptosis is a commmon characteristic in the brains of patients suffering from neurodegenerative diseases, and apoptotic cell death has been found in neurons and glial cells in AD. This review summarizes the current findings regarding the evidence for apoptosis in AD and discusses the possible involvement of apoptosis-regulating factors in the pathology of AD. Modification of the apoptotic cascade could be considered as a primary therapeutic strategy for the disease.
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    Caspase-dependent and -independent death pathways in cancer therapy (2000)
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    Apoptosis 5 (2000), S. 17-20 
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    ISSN: 1573-675X
    Keywords: Anti-tumor drugs ; apoptosis ; cancer ; caspases ; necrosis.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The majority of current anticancer therapies induce tumor cell death through the induction of apoptosis. Alterations in the apoptotic pathways may determine tumor resistance to these therapies. Activation of the proteolytic cascade involving caspase family members is a critical component of the execution of cell death in apoptotic cells. However, recent studies suggest that cell death can proceed in the absence of caspases. In this review we describe the role of caspase-dependent and -independent pathways as targets for anticancer treatment; better understanding of diverse modes of tumor cell death will help to avoid ineffective treatment and provide a molecular basis for the new strategies targeting caspase-independent death pathways in apoptosis-resistant forms of cancer.
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    A short peptide derived from the antisense homology box of Fas ligand induces apoptosis in anti-Fas antibody-insensitive human ovarian cancer cells (2000)
    Springer
    Apoptosis 5 (2000), S. 37-41 
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    ISSN: 1573-675X
    Keywords: Anti-Fas antibody ; antisense homology box-derived peptide ; apoptosis ; Fas ligand ; ovarian cancer.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract We found that a short synthetic peptide corresponding to the “antisense homology box” of Fas ligand induced apoptotic cell death of Fas-expressing human ovarian cancer cell lines. The peptide was deduced from residues 256–265 of human Fas ligand, based on the hypothesis that it should contain a specific binding site to the corresponding Fas. Interestingly, the ovarian cancer cell line NOS4, which was sensitive to anti-Fas antibody induced apoptosis, was not affected by the peptide, whereas another cell line, SKOV-3, which was insensitive to anti-Fas antibody, was killed by the peptide. Thus, this short peptide was shown to have a unique activity to induce apoptosis in human ovarian cancer cells in a manner different from anti-Fas antibody.
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    Early transitory rise in intracellular pH leads to Bax conformation change during ceramide-induced apoptosis (2000)
    Springer
    Apoptosis 5 (2000), S. 551-560 
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    ISSN: 1573-675X
    Keywords: apoptosis ; Bax ; ceramide ; mitochondria ; pH
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Ceramide can induce apoptosis through a caspase independent pathway. Bax has been described as able to kill cells in the absence of caspase activity, therefore we measured Bax in situ during ceramide-induced apoptosis using anti-Bax antibodies and flow cytometry analysis. An early (〈30 min) increase in Bax labeling was observed after the addition of several ceramide species to several hemopoietic-related cell types. On U937, this increase was not due to antigens synthesis or processing, but rather an increased accessibility or reactivity of Bax antigens for antibodies. This increased immuno-reactivity of Bax was not inhibited by Z-VAD-fmk nor leupeptin, and preceded nuclear fragmentation by several hours. Such an increase in immuno-reactivity was also observed after Fas ligation, but it occurred later (〉2 h) accompanying nuclear apoptosis, and was inhibited by Z-VAD-fmk. Bax immuno-reactivity was found to be related to intracellular pH (pHi), and C2-Ceramide (C2-Cer) induced a very early (〈10 min) transitory increase in pHi. Both Bax immuno-reactivity and pHi increases were dependent on the mitochondrial permeability transition pore (PTP) status. It was concluded from these results that C2-Cer induced a transitory increase in pHi in relation to the PTP. This rise in pHi led to conformational changes in Bax which could be responsible for further apoptosis in the C2-Cer pathway while it was a consequence of caspase activation in the Fas pathway.
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    Experimental Chagas disease: Phagocytosis of apoptotic lymphocytes deactivates macrophages and fuels parasite growth (2000)
    Springer
    Apoptosis 5 (2000), S. 221-224 
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    ISSN: 1573-675X
    Keywords: apoptosis ; macrophages ; Chagas disease ; Trypanosoma cruzi ; T lymphocytes ; vitronectin receptor ; transforming growth factor-beta ; prostaglandins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
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    URL: http://dx.doi.org/10.1023/A:1009648311490
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    Ethanol-induced apoptotic neurodegeneration in the developing brain (2000)
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    Apoptosis 5 (2000), S. 515-521 
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    ISSN: 1573-675X
    Keywords: anesthetics ; apoptosis ; barbiturates ; benzodiazepines ; ethanol ; GABAA receptors ; ketamine ; NMDA receptors ; phencyclidine ; synaptogenesis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract It has been known for three decades that ethanol, the most widely abused drug in the world, has deleterious effects on the developing human brain, but progress has been slow in developing animal models for studying this problem, and the underlying mechanisms have remained elusive. Recently, we have shown that during the synaptogenesis period, also known as the brain growth spurt period, ethanol has the potential to trigger massive neuronal suicide in the in vivo mammalian brain. The brain growth spurt period in humans spans the last trimester of pregnancy and first several years after birth. The NMDA antagonist and GABAmimetic properties of ethanol may be responsible for its apoptogenic action, in that other drugs with either NMDA antagonist or GABAmimetic actions also trigger apoptotic neurodegeneration in the developing brain. Our findings provide a likely explanation for the reduced brain mass and neurobehavioral disturbances associated with the human fetal alcohol syndrome. Furthermore, since NMDA antagonist and GABAmimetic drugs are sometimes abused by pregnant women and also are used as anticonvulsants, sedatives or anesthetics in pediatric medicine, our findings raise several complex drug safety issues. In addition, the observation that ethanol and several other drugs trigger massive neuronal apoptosis in the developing brain provides an unprecedented opportunity to study both neuropathological aspects and molecular mechanisms of apoptotic neurodegeneration in the in vivo mammalian brain.
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    URL: http://dx.doi.org/10.1023/A:1009685428847
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    Suicidal differential housekeeping gene activity in apoptosis induced by DCNP (2000)
    Springer
    Apoptosis 5 (2000), S. 379-388 
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    ISSN: 1573-675X
    Keywords: apoptosis ; ATP depletion ; cell acidification and shrinkage ; CpG-specific megabase fragmentations ; DCNP (2,6-dichloro-4-nitrophenol) ; housekeeping genes ; microarray (genechip) ; zVAD-fmk
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Previous suggestions of CpG-specific apoptotic commitment implied critical epigenetic modulation of house-keeping genes which have canonical CpG islands at 5′ promoter regions. Differential housekeeping gene activity however has not been shown. Using a focussed microarray (genechip) of 22 housekeeping genes we show this in apoptosis induced in human Chang liver cells by DCNP (2,6-dichloro-4-nitrophenol), a non-genotoxic inhibitor of sulfate detoxification. 3–7 folds downregulation of 9 genes in glycolysis, tricarboxylic acid cycle and the respiratory electron transport chain suggested gene-directed energy depletion which was correlated with observed ATP depletion. 4 folds downregulation of the pyruvate dehydrogenease gene suggested gene-directed metabolic acidosis which was correlated with observed cell acidification. Other differential housekeeping gene activity, including 4 folds upregulation of microtubular alpha-tubulin gene, and 2 folds upregulation of ubiquitin, also had a bearing on apoptosis. Broadspectrum zVAD-fmk caspase inhibition abolished 200 bp DNA ladder fragmentations but not the CpG-specific megabase fragmentations and other hallmarks of cell destruction, suggesting a caspase-independent cell death. Death appeared committed at gene-level.
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    URL: http://dx.doi.org/10.1023/A:1009695811147
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    Concanavalin A induced apoptosis in murine macrophage PU5-1.8 cells through clustering of mitochondria and release of cytochrome c (2000)
    Springer
    Apoptosis 5 (2000), S. 369-377 
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    ISSN: 1573-675X
    Keywords: apoptosis ; concanavalin A ; cytochrome c release ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Concanavalin A (ConA), normally a mitogen of T-lymphocytes, was found to be a cell cycle-independent apoptosis-inducing agent in cultured murine macrophage PU5-1.8 cells. This assertion is based on the following observations: (1) ConA increased the number of cells with hypo-diploid DNA in a dose dependent manner as revealed by flow cytometry; (2) ConA elicited DNA fragmentation and the cytotoxicity of ConA was suppressed by α-D-methylmannoside which blocks the lectin site of ConA; (3) ConA was able to release cytochrome c (cyto c) into the cytosol of PU5-1.8 cells. When isolated mitochondria were incubated with ConA, release of cyto c was observed too. Interestingly, clustering of mitochondria was found in the cytosol under a confocal microscope after ConA treatment. When cells were incubated with ConA-FITC and subsequently with mitotracker red (a probe for mitochondria), co-localization of fluorescence signals was observed. These results suggest that ConA was delivered to the mitochondria, induced mitochondrial clustering and released cyto c. Our results also show that introduction of exogenous cyto c electroporationally into ConA-untreated cells elicited DNA fragmentation. On the other hand, introduction of specific antibody against cyto c into PU5-1.8 cells suppressed the ConA-mediated cell death. Taken together, our results indicate that ConA induced apoptosis in PU5-1.8 cells through mitochondrial clustering and release of cyto c and the release of cyto c was sufficient to elicit apoptosis in PU5-1.8 cells.
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    URL: http://dx.doi.org/10.1023/A:1009691727077
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    Regulation of apoptosis in mast cells (2000)
    Springer
    Apoptosis 5 (2000), S. 435-441 
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    ISSN: 1573-675X
    Keywords: activation ; apoptosis ; death receptors ; glucocorticosteroids ; mast cells ; survival factors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Apoptosis is a physiological process of cell death that occurs in all multicellular organisms. Its dysregulation has been postulated as one of the main causes in the development of diseases such as cancer, AIDS, autoimmune diseases and allergy. Apoptosis has been mainly studied in the inflammatory cells that participate in the late and chronic stages of allergy (eosinophils, neutrophils, lymphocytes and macrophages) as a new way to elucidate the pathogenesis of this disease. Nevertheless, much less it is known about the regulation of apoptosis in the “initiators” of the allergic process: The Mast Cells. In normal conditions, mast cells are described as long-living cells that keep a constant number of cells in tissues. However, increased numbers of mast cells are observed in the late phase of asthma and in both the inflammatory and in the repair/remodeling stage of various inflammatory/fibrotic disorders. In this report, we discuss the possible mechanisms that regulate the apoptotic process in normal conditions and disease, such as survival factors and death receptors. A link between mast cell activation, during the early stages of the allergic process, and triggering of anti-apoptotic signaling pathways is also suggested as an important contributor to the extended life of mast cells.
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    URL: http://dx.doi.org/10.1023/A:1009680500988
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    Apoptosis and airway inflammation in asthma (2000)
    Springer
    Apoptosis 5 (2000), S. 473-485 
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    ISSN: 1573-675X
    Keywords: apoptosis ; asthma ; inflammation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Asthma is a disease characterized by a chronic inflammation of the airways and by structural alterations of bron-chial tissues, often referred to as airway remodelling. The development of chronic airway inflammation in asthma depends upon the continuous recruitment of inflammatory cells from the bloodstream towards the bronchial mucosa and by their subsequent activation. It is however increasingly accepted that mechanisms involved in the regulation of the survival and apoptosis of inflammatory cells may play a central role in the persistent inflammatory process characterizing this disease. Increased cellular recruitment and activation, enhanced cell survival and cell:cell interactions are therefore the key steps in the development of chronic airway inflammation in asthma, and represent the major causes for tissue damge, repair and remodelling.
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    URL: http://dx.doi.org/10.1023/A:1009661406440
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    The molecular control of DNA damage-induced cell death (2000)
    Springer
    Apoptosis 5 (2000), S. 491-507 
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    ISSN: 1573-675X
    Keywords: apoptosis ; Bcl-2 ; caspases ; death receptors ; DNA damage ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Because of the singular importance of DNA for genetic inheritance, all organisms have evolved mechanisms to recognize and respond to DNA damage. In metazoans, cells can respond to DNA damage either by undergoing cell cycle arrest, to facilitate DNA repair, or by undergoing cell suicide. Cell death can either occur by activation of the apoptotic machinery or simply be a consequence of irreparable damage that prevents further cell division. In germ cells, mechanisms for limiting alterations to the genome are required for faithful propagation of the species whereas in somatic cells, responses to DNA damage prevent the accumulation of mutations that might lead to aberrant cell proliferation or behavior. Several of the genes that regulate cellular responses to DNA damage function as tumor suppressors. The clinical use of DNA damaging agents in the treatment of cancer can activate these tumor suppressors and exploits the cellular suicide and growth arrest mechanisms that they regulate. It appears that in some but not all types of tumors the propensity to undergo apoptosis is a critical determinant of their sensitivity to anti-cancer therapy. This review describes current understanding of the molecular control of DNA damage-induced apoptosis with particular attention to its role in tumor suppression and cancer therapy.
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    URL: http://dx.doi.org/10.1023/A:1009617727938
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    Protection of apoptotic cell death by protein A (2000)
    Springer
    Apoptosis 5 (2000), S. 509-514 
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    ISSN: 1573-675X
    Keywords: apoptosis ; protection ; protein A ; pro- and anti-apoptotic factor
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The word “Apoptosis” or pragrammed cell death is described as the ultimate end of multiple cellular events converging from numerous initiating events to the ultimate death of a cell or organism. Several processes, such as initiation of death signals at the plasma membrane, expression of pro-apoptotic oncoproteins, activation of death proteases, endonucleases etc., that ultimately coalesce to a common irreversible execution phase, lead to cell demise. Counteracting the death signals are cell survival factors. A balance between the cell death and cell survival factors plays a major role in the decision making process as to whether a cell should die or must live. It is, therefore, hypothesized that if the balance can be shifted in favor of cell survival, one might be able to arrest the aging process, save the injured cells or else if the balance is shifted toward cell-kill it might help destroy tumors and other undesirable cells. Protein A (PA) of Staphylococcus aureus has been found to have multifarious biological response modifying properties. It has been shown to possess anti-tumor, anti-toxic, anti-parasitic and antifungal activities. It also acts as a potent immunostimulator. PA can protect bone marrow progenitor cells from zidovudin(AZT)-induced apoptosis and can stimulate immunocyte proliferation, thereby helping to replenish/restore the depleted hematopoietic cell pool. Such ability to replenish hematopoietic cells is a common property of PA observed against a number of toxic drugs/chemicals, such as cyclophosphamide, benzene, aflatoxin, salmonella endotoxin, etc. Interestingly, it was further demonstrated in our laboratory that PA can selectively kill tumor cells without affecting normal cells of the host. A search for the mechanisms of PA action revealed that this bacterial protein could shift the balance between pro- and anti-apoptotic proteins in favor of survival in normal cells, but in favor of cell death in tumor cells at a particular dose level. This unique property of PA suggests that controlled use of such type of Biological Response Modifier might help in controlling both cell growth and death phenomena.
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    URL: http://dx.doi.org/10.1023/A:1009633412009
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    ATM dependent apoptosis in the nervous system (2000)
    Springer
    Apoptosis 5 (2000), S. 523-529 
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    ISSN: 1573-675X
    Keywords: apoptosis ; ATM ; DNA damage ; ionizing radiation ; p53
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Ataxia-telangiectasia is a human syndrome resulting from mutations of the ATM protein kinase that is characterized by radiation sensitivity and neurodegeneration. Although neuroprotective, the molecular details of ATM function in the nervous system are uncertain. However, in the mouse, Atm is essential for ionizing radiation-induced apoptosis in select postmitotic populations of the developing nervous system. Atm-dependent apoptosis in the nervous system also requires p53, consistent with the well-established link of p53 as a major substrate of ATM. Furthermore, the proapoptotic effector Bax is also required for most, but not all, Atm-dependent apoptosis. Therefore, after DNA damage in the developing nervous system, Atm initiates a p53-dependent apoptotic cascade in differentiating neural cells. Together, these data suggest ATM-dependent apoptosis may be important for elimination of neural cells that have accumulated genomic damage during development, thus preventing dysfunction of these cells later in life.
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    URL: http://dx.doi.org/10.1023/A:1009637512917
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    Caspase-dependent and independent cell death in rat hepatoma 5123tc cells (2000)
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    Apoptosis 5 (2000), S. 265-275 
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    ISSN: 1573-675X
    Keywords: apoptosis ; DNA fragmentation ; necrosis ; phosphorylation ; protease inhibitors
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The objective of this study was to establish whether apoptosis in 5123tc rat hepatoma cells required the caspase-3 dependent pathway. Apoptosis was induced by either growth factor deprivation or treatment with a topoisomerase II inhibitor, VM26, in the absence or presence of caspase inhibitors (DEVD-fmk, z-VAD-fmk and BAF). The results indicated that, although these inhibitors at 10 μM concentration completely blocked caspase-3 activity, they had no effect on either the rate of cell death or on any other apoptotic features, e.g., chromatin condensation, DNA fragmentation, protein cleavage, suggesting that caspase-3 was not required to mediate nuclear destruction in these hepatoma cells. At higher concentrations, up to 100 μM, z-VAD-fmk and BAF, but not DEVD-fmk, did block apoptosis, however, they also caused cell swelling and membrane permeabilization, which are the hallmarks of necrotic cell death. Clearly, high concentrations of these inhibitors must have interfered non-specifically with other metabolic pathways, e.g., z-VAD-fmk at a high concentration blocked protein phosphorylation, and caused cell death by a different mechanism.
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    URL: http://dx.doi.org/10.1023/A:1009608630145
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    Homocysteine-thiolactone induces caspase-independent vascular endothelial cell death with apoptotic features (2000)
    Springer
    Apoptosis 5 (2000), S. 403-411 
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    ISSN: 1573-675X
    Keywords: apoptosis ; atherosclerosis ; cell culture ; endothelial function ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Objective. Cell death is generally classified into two large categories: apoptosis, which represents active, physiological programmed cell death, and necrosis, which represents passive cell death without underlying regulatory mechanisms. Apoptosis plays an important role in tissue homeostasis and its role in endothelium integrity can be influenced by the functional status of endothelial cells. Homocysteine, a sulfated amino-acid product of methionine demethylation, is an independent risk factor for vascular disease (arterial and venous thombosis). Our goal was to investigate the thiol-derivatives effect on the endothelial cell apoptosis. Methods. Three parameters were measured: mitochondrial membrane potential using DiOC6(3) as the probe, DEVDase activation, and phosphatidylserine exposure on the cell surface with fluorosceinated annexin V labeling which allows apoptosis to be distinguished from necrosis. Results. Homocysteine-thiolactone induced endothelial cell apoptosis in a concentration-dependent manner (range: 50–200 μ M), independently of the caspase pathway. Only homocysteine-thiolactone, among the thiol derivatives tested, induced apoptosis. Apoptosis was not influenced by the serum concentration in culture medium, suggesting that the observed apoptotic process could occur in vivo. None of the inhibitors used (e.g., leupeptin, fumosinin Bl, catalase, or z-VAD-fmk) was able to prevent homocysteine-induced apoptosis of vascular endothelial cells. Conclusion. The apoptosis of vascular endothelial cells induced by high concentration of homocysteine-thiolactone might be one step atherosclerotic cardiovascular disease, and contribute to its complication.
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    URL: http://dx.doi.org/10.1023/A:1009652011466
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    Regulation of neutrophil apoptosis: A role for protein kinase C and phosphatidylinositol-3-kinase (2000)
    Springer
    Apoptosis 5 (2000), S. 451-458 
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    ISSN: 1573-675X
    Keywords: apoptosis ; inflammation ; neutrophil ; PI-3-kinase ; PKC ; T-cell
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Neutrophils play a central role in host defense and are recruited in vast numbers to sites of infection where they phagocytose and kill invading bacterial pathogens. Neutrophils have a short half-life that is extended at the inflamed site by pro-inflammatory cytokines and contact with bacterial cell walls. Normal resolution of inflammation involves the removal of neutrophils and other inflammatory cells by the induction of apoptosis. Spontaneous neutrophil apoptosis does not require Fas ligation, but is mediated by caspases 3, 8 and possibly caspase 9 and also involves activation of protein kinase C-δ. With chronic inflammatory disease, neutrophil apoptosis is delayed by pro-inflammatory cytokines, leading to persistence of neutrophils at the inflamed site and non-specific tissue damage. Here we discuss the evidence for inhibition of neutrophil apoptosis via signaling though PI-3-kinase and downstream pathways, including PDK-1 and PKB. Therapeutic strategies to resolve chronic inflammation could therefore usefully target neutrophil apoptosis and the PI-3-kinase or PKC-δ signaling pathways.
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    URL: http://dx.doi.org/10.1023/A:1009601220552
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    GnRH-Bik/Bax/Bak chimeric proteins target and kill adenocarcinoma cells; the general use of pro-apoptotic proteins of the Bcl-2 family as novel killing components of targeting chimeric proteins (2000)
    Springer
    Apoptosis 5 (2000), S. 531-542 
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    ISSN: 1573-675X
    Keywords: adenocarcinoma cells ; apoptosis ; Bcl-2 family proteins ; chimeric proteins ; GnRH-binding site ; targeting
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract In recent years chimeric proteins carrying bacterial toxins as their killing moiety, have been developed to selectively recognize and kill cell populations expressing speciific receptors. The involvement of Gonadotropin releasing hormone (GnRH) has been demonstrated in several adenocarcinomas and a GnRH-bacterial toxin chimeric protein (GnRH-PE66) was thus developed and found to specifically target and kill adenocarcinoma cells both in vitro and in vivo. Because of the immunogenicity and the non-specific toxicity of the bacterial toxins, we have developed new chimeric proteins, introducing apoptosis inducing proteins of the Bcl-2 family as novel killing components. Sequences encoding the human Bik, Bak or Bax proteins were fused to the GnRH coding sequence at the DNA level and were expressed in E. coli. GnRH-Bik, GnRH-Bak and GnRH-Bax new chimeric proteins efficiently and specifically inhibited the cell growth of adenocarcinoma cell lines and eventually led to cell death. All three Bcl2-proteins-based chimeric proteins seem to induce apoptosis within the target cells, without any additional cell death stimulus. Apoptosis-inducing-proteins of the Bcl-2 family targeted by the GnRH are novel potential therapeutic reagents for adenocarcinoma treatment in humans. This novel approach could be widely applied, using any molecule that binds a specific cell type, fused to an apoptosis-inducing protein.
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    URL: http://dx.doi.org/10.1023/A:1009689529756
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    CDK inhibitors suppress apoptosis induced by chemicals and by excessive expression of a cell death gene, reaper, in Drosophila cells (2000)
    Springer
    Apoptosis 5 (2000), S. 543-550 
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    ISSN: 1573-675X
    Keywords: apoptosis ; CDK ; cell cycle ; cell death gene ; drosophila ; reaper
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The present study was aimed to investigate whether or not cyclin-dependent kinases (CDKs) participate in different cascades leading to apoptosis. We examined the effects of two CDK inhibitors, olomoucine (OLM) and buty-rolactone-I (BL-I), on apoptosis induced in two kinds of Drosophila cell lines. Increases of caspase activity induced by actinomycin D, cycloheximide, H-7 or A23187 in a Drosophila neuronal cell line, ML-DmBG2-c2, and induced by excessive expression of a Drosophila cell death gene, reaper, in Drosophila S2 cells were suppressed by 24-h pretreatment of each CDK inhibitor. Concomitant with the suppression of the caspase activity, fragmentations of cells and DNA, representatives of apoptosis, were also inhibited. These results suggest that CDK(s) participates in progression of apoptosis. However, these effects of the CDK inhibitors were also observed even at lower doses which did not affect cell proliferation. Therefore, it was shown that apoptosis is not always related to cell cycle in Drosophila cells. It was also suggested that the target(s) of the CDK inhibitors locates upstream of caspase in the cascade(s) of apoptosis.
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    Induction of Apoptosis in WEHI 231 Cells by Cationic Liposomes (2000)
    Springer
    Pharmaceutical research 17 (2000), S. 515-520 
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    ISSN: 1573-904X
    Keywords: apoptosis ; cationic liposome ; B cell ; WEHI 231 ; reactive oxygen species
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Purpose. Liposomes are of considerable interest as drug carriers andimmunoadjuvants. However, few investigators have studied thechanges exerted by liposomes in the cells with which they interact.The purpose of this study was to investigate whether liposomes induceapoptosis in B cells. Methods. The mouse immature B cell line WEHI 231 cells and mousesplenic B cells were treated with liposomes, and the induction ofapoptosis was evaluated by monitoring changes in DNA content, DNAfragmentation and chromatin condensation by flow cytometry, agarosegel electrophoresis and by morphological investigation. Results. Cationic liposomes induced apoptosis in WEHI 231 cells, butneutral and anionic liposomes did not. A contact time of 30 minbetween WEHI 231 cells and cationic liposomes was sufficient toinduce apoptosis, and 80% of the cells showed hypodiploid DNAcontent. Apoptosis induced by cationic liposomes composed ofstearylamine was inhibited by addition of the oxidant scavenger,N-acetyl-cysteine. Conclusions. Cationic liposomes induced apoptosis in WEHI 231 cells,and the production of reactive oxygen species is important in theregulation of apoptosis induced by cationic liposomes. It is well knownthat cationic liposomes show cytotoxicity, and apoptosis may be oneof the causes of this toxicity.
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    Programmed cell death in cereal aleurone (2000)
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    Plant molecular biology 44 (2000), S. 255-266 
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    ISSN: 1573-5028
    Keywords: abscisic acid ; apoptosis ; gibberellic acid ; nuclease ; programmed cell death ; protease
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Progress in understanding programmed cell death (PCD) in the cereal aleurone is described. Cereal aleurone cells are specialized endosperm cells that function to synthesize and secrete hydrolytic enzymes that break down reserves in the starchy endosperm. Unlike the cells of the starchy endosperm, aleurone cells are viable in mature grain but undergo PCD when germination is triggered or when isolated aleurone layers or protoplasts are incubated in gibberellic acid (GA). Abscisic acid (ABA) slows down the process of aleurone cell death and isolated aleurone protoplasts can be kept alive in media containing ABA for up to 6 months. Cell death in barley aleurone occurs only after cells become highly vacuolated and is manifested in an abrupt loss of plasma membrane integrity. Aleurone cell death does not follow the apoptotic pathway found in many animal cells. The hallmarks of apoptosis, including internucleosomal DNA cleavage, plasma membrane and nuclear blebbing and formation of apoptotic bodies, are not observed in dying aleurone cells. PCD in barley aleurone cells is accompanied by the accumulation of a spectrum of nuclease and protease activities and the loss of organelles as a result of cellular autolysis.
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    Caspase-like protease involvement in the control of plant cell death (2000)
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    Plant molecular biology 44 (2000), S. 417-428 
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    ISSN: 1573-5028
    Keywords: apoptosis ; baculovirus p35 ; Bcl-2-like proteins ; caspases ; cell death ; hypersensitive response ; mitochondria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Cell death as a highly regulated process has now been recognized to be an important, if not essential, pathway that is ubiquitous in all multicellular eukaryotes. In addition to playing key roles in the morphogenesis and sculpting of the organs to give rise to highly specialized forms and shapes, cell death also participates in the programmed creation of specialized cell types for essential functions such as the selection of B cells in the immune system of mammals and the formation of tracheids in the xylem of vascular plants. Studies of apoptosis, the most well-characterized form of animal programmed cell death, have culminated in the identification of a central tripartite death switch the enzymatic component of which is a conserved family of cysteine proteases called caspases. Studies in invertebrates and other animal models suggest that caspases are conserved regulators of apoptotic cell death in all metazoans. In plant systems, the identities of the main executioners that orchestrate cell death remain elusive. Recent evidence from inhibitor studies and biochemical approaches suggests that caspase-like proteases may also be involved in cell death control in higher plants. Furthermore, the mitochondrion and reactive oxygen species may well constitute a common pathway for cell death activation in both animal and plant cells. Cloning of plant caspase-like proteases and elucidation of the mechanisms through which mitochondria may regulate cell death in both systems should shed light on the evolution of cell death control in eukaryotes and may help to identify essential components that are highly conserved in eukaryotes.
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    Mitochondrial Calcium Signaling Driven by the IP3 Receptor (2000)
    Springer
    Journal of bioenergetics and biomembranes 32 (2000), S. 15-25 
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    ISSN: 1573-6881
    Keywords: Mitochondria ; endoplasmic reticulum ; Ca2+ ; IP3 ; local signaling ; energy metabolism ; apoptosis ; necrosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Many agonists bring about their effects on cellular functions through a rise incytosolic [Ca2+]([Ca2+]c) mediated by the second messenger inositol 1,4,5-trisphosphate (IP3). Imaging studiesof single cells have demonstrated that [Ca2+]c signals display cell specific spatiotemporalorganization that is established by coordinated activation of IP3 receptor Ca2+ channels.Evidence emerges that cytosolic calcium signals elicited by activation of the IP3 receptors areefficiently transmitted to the mitochondria. An important function of mitochondrial calciumsignals is to activate the Ca2+-sensitive mitochondrial dehydrogenases, and thereby to meetdemands for increased energy in stimulated cells. Activation of the permeability transitionpore (PTP) by mitochondrial calcium signals may also be involved in the control of cell death.Furthermore, mitochondrial Ca2+ transport appears to modulate the spatiotemporal organizationof [Ca2+]c responses evoked by IP3 and so mitochondria may be important in cytosolic calciumsignaling as well. This paper summarizes recent research to elucidate the mechanisms andsignificance of IP3-dependent mitochondrial calcium signaling.
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    Mitochondria in Ca2+ Signaling and Apoptosis (2000)
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    Journal of bioenergetics and biomembranes 32 (2000), S. 35-46 
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    ISSN: 1573-6881
    Keywords: Ca2+ signaling ; inositol 1,4,5-trisphosphate receptor ; mitochondrial Ca2+ uptake ; mitochondrial Ca2+ efflux ; permeability transition ; apoptosis ; Bcl-2 family
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Chemistry and Pharmacology , Physics
    Notes: Abstract Cellular Ca2+ signals are crucial in the control of most physiological processes, cell injuryand programmed cell death; mitochondria play a pivotal role in the regulation of such cytosolicCa2+ ([Ca2+]c) signals. Mitochondria are endowed with multiple Ca2+ transport mechanismsby which they take up and release Ca2+ across their inner membrane. These transport processesfunction to regulate local and global [Ca2+]c, thereby regulating a number of Ca2+-sensitivecellular mechanisms. The permeability transition pore (PTP) forms the major Ca2+ effluxpathway from mitochondria. In addition, Ca2+ efflux from the mitochondrial matrix occursby the reversal of the uniporter and through the inner membrane Na+/Ca2+ exchanger. Duringcellular Ca2+ overload, mitochondria take up [Ca2+]c, which, in turn, induces opening of PTP,disruption of mitochondrial membrane potential (ΔΨm) and cell death. In apoptosis signaling,collapse of ΔΨ;m and cytochrome c release from mitochondria occur followed by activationof caspases, DNA fragmentation, and cell death. Translocation of Bax, an apoptotic signalingprotein from the cytosol to the mitochondrial membrane, is another step during thisapoptosis-signaling pathway. The role of permeability transition in the context of cell death in relationto Bcl-2 family of proteins is discussed.
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    URL: http://dx.doi.org/10.1023/A:1005508311495
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    (−)1-(Benzofuran-2-yl)-2-propylaminopentane Shows Survival Effect on Cortical Neurons Under Serum-Free Condition Through Sigma Receptors (2000)
    Springer
    Cellular and molecular neurobiology 20 (2000), S. 695-702 
    Details
    ISSN: 1573-6830
    Keywords: apoptosis ; impulse enhancer ; sigma receptor ; neuroprotection ; (+)-pentazocine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract SUMMARY 1. The rapid cell death of cortical neurons in serum-free culture was rescued by the condition medium from the high-density culture, but not by brain-derived neurotrophic factor or basic fibroblast growth factor. 2. Similar rescue was observed by the addition of (−)BPAP, an impulse enhancer, and (+)-pentazocine, a sigma receptor agonist. These actions were blocked by BD1063, a sigma receptor antagonist. 3. (−)BPAP showed a weak displacement activity in the [3H]pentazocine binding to synaptic membranes from rat cerebral cortex. 4. These findings suggest that (−)BPAP and (+)-pentazocine have unique survival activity on cortical neurons through sigma receptors.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1007050808754
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    Apoptosis evaluation in epithelial cells exposed to different chemicals: relevance of floating cells (2000)
    Springer
    Cell biology and toxicology 16 (2000), S. 53-62 
    Details
    ISSN: 1573-6822
    Keywords: apoptosis ; cell adhesion ; cytotoxicity tests ; epithelial cells ; morphology
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The recent increase in understanding of cell death has promoted new approaches in toxicological studies, mainly those dealing within vitro systems where the evaluation of cell death has been the most widely adopted end-point in measuring the effects of chemical toxicants. The aim of this study was to investigate the possibility of improving the traditional cytotoxicity test protocols in order to produce more specific information on the type of cell death induced by exposure to toxicants. In particular, we characterized the mode of cell death in an established epithelial cell line, HEp-2 cells, which is frequently used in cytotoxicity testing owing to its easy handling and standardization of culture conditions. Reference chemicals for apoptosis and necrosis were selected as controls, together with other molecules that have been shown, in preliminary studies, to induce various morphological and structural modifications in relation to cell death. The results obtained show that: (a) the floating fraction of treated cells gives the clearest picture of the necrotic/apoptotic distribution; (b) morphological analysis is crucial for characterization of apoptosis; (c) more than one cytotoxic end-point is necessary to clearly identify the type of cell death.
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    URL: http://dx.doi.org/10.1023/A:1007696604725
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    Induction of apoptosis in normal cultured rat hepatocytes and in Hep3B, a human hepatoma cell line (2000)
    Springer
    Cell biology and toxicology 16 (2000), S. 185-200 
    Details
    ISSN: 1573-6822
    Keywords: apoptosis ; hepatic cells ; culture conditions
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The in vitro occurrence of apoptosis in hepatic cells has not been well characterized because it depends on apoptosis inducing-agents and culture conditions. Furthermore, for a given hepatic cell and the same agent, discrepant results have been reported depending on the technique used to evaluate the proportion of apoptotic cells. In this study, we compared the effects of several apoptosis-inducing agents – transforming growth factor β1 (TGF-β1), retinoic acid (RA), okadaic acid (OA), and cycloheximide (CY) – on two types of hepatic cells, the human hepatoma cell line Hep3B and normal rat hepatocytes, maintained either plated for 24 to 48 h or in suspension for 20 h. Chromatin condensation and/or nucleus fragmentation were investigated morphologically by DAPI staining. DNA fragmentation was investigated biochemically by agarose gel electrophoresis and poly(ADP-ribose) polymerase (PARP) cleavage was studied by western blot. Apoptotic cells were quantified either by counting cells on UV microscopy after DAPI staining or by flow cytometry. Nuclear changes, the ladder pattern on DNA electrophoresis and PARP cleavage were observed in plated cells, hepatoma cells and normal rat hepatocytes, with all inducers but especially with OA. Semiquantification confirmed that OA was a strong inducer in plated cells under the present conditions, since about 14% and 30% of Hep3B cells (with DAPI staining and flow cytometry, respectively) were apoptotic after 48 h treatment, while, with the other inducers, apoptosis was weaker and discrepancies were also observed between the two counting methods (TGF-β1; 4% and 12%; RA, 7% and 12%; CY, 4% and 16%, with DAPI staining and flow cytometry, respectively). OA induced a moderate apoptosis in cultured hepatocytes (13% with DAPI staining), while TGF-β1, RA and CY were found to be weakly apoptotic (respectively 4% for the first two and 6% for the last ) after 48 h. In contrast, in suspension cells, apoptosis was observed neither in Hep3B cells nor in normal hepatocytes, whatever the apoptotic inducer and whatever the techniques used to detect apoptosis. In conclusion, our results show that induction of apoptosis in hepatic cells depends not only on the apoptosis-inducing agent but also on the culture conditions.
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    URL: http://dx.doi.org/10.1023/A:1007611022477
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    Successful separation of apoptosis and necrosis pathways in HaCaT keratinocyte cells induced by UVB irradiation (2000)
    Springer
    Cell biology and toxicology 16 (2000), S. 293-302 
    Details
    ISSN: 1573-6822
    Keywords: apoptosis ; differentiation ; keratinocytes ; UVB radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract UVB irradiation can induce apoptotic, necrotic, and differentiation pathways in normal human keratinocytes. The present study was undertaken to determine at what dose of UVB each of these pathways is induced and whether these pathways are distinct or overlapping. We have observed that UVB induces fragmentation of DNA in human HaCaT keratinocytes, in a bimodal manner. Low doses of UVB, 5–20 mJ/cm2, increase the levels of apoptosis as shown by increased levels of fragmented DNA, Fas, PARP, and FasL protein, and the number of apoptotic cells as assessed by FACS analysis. At higher doses of UVB (20 and 30 mJ/cm2) the number of apoptotic cells becomes reduced, as does the amount of Fas, PARP, and FasL protein. At these higher doses, cell viability is decreased as measured by DNA synthesis (BrdU labeling) neutral red uptake, which represents an increasing necrotic phenotype. Expression of markers of keratinocyte differentiation, involucrin, keratin K1, and keratin K10, are also observed to decrease with increasing UVB dose. These changes are accompanied by a further increase in DNA fragmentation. We conclude that low doses of UVB (5–20 mJ/cm2) induced an apoptotic pathway, whereas increasing doses (greater than 20 mJ/cm2) of UVB produce a direct necrotic effect and inhibit terminal differentiation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1026746330146
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    Critical Temporal Modulation of Neuronal Programmed Cell Injury (2000)
    Springer
    Cellular and molecular neurobiology 20 (2000), S. 383-400 
    Details
    ISSN: 1573-6830
    Keywords: apoptosis ; annexin ; DNA fragmentation ; ischemia ; nitric oxide ; primary hippocampal neurons
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract 1. As a free radical, nitric oxide (NO) may be toxic to neurons through mechanisms that directly involve DNA damage. Lubeluzole, a novel benzothiazole compound, has recently been demonstrated to be neuroprotective through the signal transduction pathways of NO. We therefore examined whether neuroprotection by lubeluzole was dependent upon the molecular pathways of programmed cell death (PCD). 2. In primary hippocampal neurons, evidence of PCD was determined by hematoxylin and eosin (H&E) stain, transmission electron microscopy, and annexin-V binding. NO administration with the NO generators sodium nitroprusside (300 μM) or SIN-1 (300 μM) directly induced PCD. 3. Neurons positive for PCD increased from 22 ± 3% (untreated) to 72 ± 3% (NO) over a 24-hr period. Coadministration of NO and lubeluzole (750 nM), a neuroprotective concentration, actively decreased PCD expression on H&E stain from 72 ± 3% (NO only) to 25 ± 3% (NO and lubeluzole). Significant reduction in DNA fragmentation by lubeluzole also was evident on electron microscopy. Application of lubeluzole in concentrations that were not neuroprotective or administration of the biologically inactive R-isomer did not significantly alter NO-induced PCD, suggesting that neuroprotection by lubeluzole was intimately linked to the modulation of PCD. Lubeluzole also was able to prevent the initial stages of cellular membrane inversion labeled with annexin-V binding, an early and sensitive indicator of PCD. Interestingly, the critical period for lubeluzole to reverse PCD induction appeared to be within the first 4 hr following NO exposure. 4. Further investigation into the neuroprotective pathways that alter PCD may provide greater insight into the molecular mechanisms that ultimately determine neuronal injury.
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    URL: http://dx.doi.org/10.1023/A:1007070311203
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    RGD peptide-induced apoptosis in human leukemia HL-60 cells requires caspase-3 activation (2000)
    Springer
    Cell biology and toxicology 16 (2000), S. 275-283 
    Details
    ISSN: 1573-6822
    Keywords: apoptosis ; RGD ; HL-60 ; caspase-3
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract RGD motif-containing peptides have been used in various studies of cell adhesion and growth. We report that RGD triggered apoptosis at a concentration of 1 mmol/L, whereas RAD-containing peptides failed to induce apoptosis in HL-60 cells. RGD-treated cells revealed internucleosomal DNA fragmentation. Western blot reveals caspase-3 activation in RGD peptide-treated cells. A caspase-3 inhibitor z-VAD-FMK completely blocked the apoptosis, but a caspase-1 inhibitor (Ac-YVAD-CMK) and caspase-2 inhibitor (z-VDVAD-FMK) did not block the apoptosis, suggesting that caspase-3 might have a critical role in the execution process of apoptosis induced by RGD. RGD peptides have been used extensively to inhibit tumor metastasis. Our results should help in further understanding the RGD peptide-induced apoptosis, which is important since RGD peptides have a potential role in therapies of the future.
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    URL: http://dx.doi.org/10.1023/A:1026758429238
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    Immunochemical characteristics of a novel cell death receptor and a decoy receptor on granulosa cells of porcine ovarian follicles (2000)
    Springer
    Cytotechnology 33 (2000), S. 189-201 
    Details
    ISSN: 1573-0778
    Keywords: apoptosis ; cell death receptor ; decoyreceptor ; granulosa cell ; porcine ovary
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Previously, we prepared an IgM monoclonal antibody(PFG-1) which specifically recognized a cell-membraneglycoprotein (PFG-1 antigen; 55 kD, pI 5.9),immunohistochemically reacted with granulosa cells ofhealthy follicles but not of atretic follicles, andinduced granulosa cell apoptosis. In the presentstudy, an IgM monoclonal antibody (PFG-3) capable ofinducing granulosa cell apoptosis and an IgGmonoclonal antibody (PFG-4) not capable of inducingapoptosis were produced against granulosa cellsprepared from healthy antral follicles of porcineovaries. Two-dimensional Western blotting analysisrevealed that PFG-3 specifically recognized twocell-membrane proteins (named PFG-3-1 andPFG-3-2/PFG-1 antigens; 42 kD, pI 5.2 and 55 kD, pI5.9, respectively) of healthy granulosa cells, andthat PFG-4 recognized the same two cell-membraneproteins. In atretic granulosa cells, PFG-3-2/PFG-1antigen disappeared. Immunochemical reactions of theseantibodies were only detected in follicular granulosacells but not any other ovarian tissues or organs.PFG-3 and PFG-4 immunohistochemically reacted withgranulosa cells of healthy and atretic follicles. Whenthe isolated granulosa cells prepared from healthyfollicles were cultured in medium containing PFG-3,the cells underwent apoptosis, and co-incubation withPFG-4 inhibited PFG-3-inducible apoptosis. Theseobservations suggested that PFG-3-2/PFG-1 antigen isa novel cell death receptor which is different fromthe apoptosis-mediating receptors (Fas/Apo-1/CD95 orTNF receptor), and that PFG-3-1 antigen may act as adecoy receptor and inhibit apoptotic signal transmission.
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    URL: http://dx.doi.org/10.1023/A:1008146119761
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    Regulated overexpression of the survival factor bcl-2 in CHO cells increases viable cell density in batch culture and decreases DNA release in extended fixed-bed cultivation (2000)
    Springer
    Cytotechnology 32 (2000), S. 45-61 
    Details
    ISSN: 1573-0778
    Keywords: apoptosis ; Bcl-2 ; fixed-bed reactor ; regulated gene expression
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Using multicistronic expression technology we generated a stable Chinese hamster ovary (CHO) cell line (MG12) expressing a model secreted heterologous glycoprotein, the secreted form of the human placental alkaline phosphatase (SEAP), and bcl-2, best known as an apoptosis inhibitor, in a tetracycline-repressible dicistronic configuration. In batch cultivations in serum-containing medium, MG12 cells reached twice the final viable cell density when Bcl-2 was overexpressed (in the absence oftetracycline) compared to MG12 populations culturedunder tetracycline-containing conditions (bcl-2repressed). However, bcl-2-expressing MG12 cellsshowed no significant retardation of the decline phasecompared to batch cultures in which the dicistronicexpression unit was repressed.Genetic linkage of bcl-2 expression with the reporter protein SEAP in our multicistronic construct allowed online monitoring of Bcl-2 expression over an extended, multistage fixed-bed bioreactor cultivation. The cloned multicistronic expression unit proved to be stable over a 100 day bioreactor run. CHO MG12 cells in the fixed-bed reactor showed a drastic decrease in the release of DNA into the culture supernatant under conditions of reduced tetracycline (and hencederepressed SEAP and bcl-2 overexpression). This observation indicated enhanced robustness associated with bcl-2 overexpression, similar to recent findings for constitutive Bcl-2-overexpressing hybridoma cells under the same bioprocess conditions. These findings indicate, in these serum-containing CHO cell cultures, that overexpression of Bcl-2 results in desirable modifications in culture physiology.
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    URL: http://dx.doi.org/10.1023/A:1008168522385
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    Treatment of mouse melanoma cells with phorbol 12-myristate 13-acetate counteracts mannosylerythritol lipid-induced growth arrest and apoptosis (2000)
    Springer
    Cytotechnology 33 (2000), S. 123-130 
    Details
    ISSN: 1573-0778
    Keywords: apoptosis ; mannosylerythritol lipid ; melanoma ; protein kinase C
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Mannosylerythritol lipid (MEL), an extracellularglycolipid from yeast, induces the differentiation ofHL-60 promyelocytic leukemia cells towardsgranulocytes. We show here that MEL is also a potentinhibitor of the proliferation of mouse melanoma B16cells. Flow-cytometric analysis of the cell cycle ofMEL-treated B16 cells revealed the accumulation ofcells in the sub-G0/G1 phase, which is a hallmark ofcells undergoing apoptosis. Treatment of B16 cellsfor 24 h with phorbol 12-myristate 13-acetate (PMA),an activator of protein kinase C (PKC), did notinterfere with the growth and survival of the cells,but it effectively counteracted the MEL-induced growtharrest and apoptosis. The activity of PKC was reducedin B16 cells treated with MEL at a concentration atwhich MEL induced apoptosis. However, incubation withPMA in addition to MEL reversed this reduction in theactivity of PKC. These results suggest thatconverging signaling pathways are triggeredindependently by MEL and PMA and that the signalsmight both be mediated by PKC.
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    URL: http://dx.doi.org/10.1023/A:1008129616127
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    Necessity of Superoxide Production for Development of Etiolated Wheat Seedlings (2000)
    Springer
    Biochemistry (Moscow) 65 (2000), S. 1357-1361 
    Details
    ISSN: 1608-3040
    Keywords: antioxidant ; Endomyces magnusii ; apoptosis ; BHT ; DNA ; fragmentation ; DNA synthesis ; ontogenesis ; ROS ; plant ; protein synthesis ; superoxide ; wheat
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract It was found that production of superoxide (O2 – ·) is crucial for normal morphogenesis of etiolated wheat seedlings in the early stages of plant development. The development of etiolated wheat seedlings was shown to be accompanied with cyclic changes in the rate of O2 – · production both in the entire intact seedling and in its separated organs (leaf, coleoptile). First increase in the rate of O2 – · production was clearly observed in the period from two to four days of seedling development, then the rate of O2 – · production decreased to the initial level, and then it increased again for two days to a new maximum. An increase in O2 – · production in the period of the first four days of seedling development correlates with an increase in DNA and protein contents in the coleoptile. The second peak of increased rate of O2 – · production observed on the sixth or seventh day of seedling development coincides with a decrease in DNA and protein contents and apoptotic internucleosomal nuclear DNA fragmentation in the coleoptile. Incubation of seedlings in the presence of the antioxidant BHT (ionol) strongly affects their development but it does not influence the increase in DNA and protein contents for the initial four days of seedling life, and it slows down the subsequent age-dependent decrease in protein content and fully prevents the age-dependent decrease in DNA content in the coleoptile. A decrease in the O2 – · amount induced by BHT distorts the seedling development. BHT retards seedling growth, presumably by suppression of cell elongation, and it increases the life span of the coleoptile. It seems that O2 – · controls plant growth by cell elongation at the early stages of seedling development but later O2 – · controls (induces) apoptotic DNA fragmentation and protein disintegration.
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    URL: http://dx.doi.org/10.1023/A:1002892520658
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    Peptide Bioregulators Inhibit Apoptosis (2000)
    Springer
    Bulletin of experimental biology and medicine 130 (2000), S. 1175-1176 
    Details
    ISSN: 1573-8221
    Keywords: peptide bioregulators ; apoptosis ; aging
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The effects of peptide bioregulators epithalon and vilon on the dynamics of irradiation-induced apoptotic death of spleen lymphocytes in rats indicate that these agents inhibit physiologically programmed cell death. The antiapoptotic effect of vilon was more pronounced, which corroborates the concept on tissue-specific effect of peptide bioregulators.
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    URL: http://dx.doi.org/10.1023/A:1017584018746
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    Expression of CD95 on Peripheral Blood Lymphocytes in Patients with Autoimmune Diseases and Neoplasms (2000)
    Springer
    Bulletin of experimental biology and medicine 130 (2000), S. 892-894 
    Details
    ISSN: 1573-8221
    Keywords: immune deficiency ; apoptosis ; lymphocytes ; neoplasms and autoimmune diseases
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract CD95 expression on peripheral blood lymphocytes in patients with neoplasms was higher than in patients with autoimmune disorders. Apoptosis of T cells increased during tumor growth. The data suggest that neoplasms are accompanied by more severe immune dysfunction than autoimmune disorders.
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    URL: http://dx.doi.org/10.1023/A:1015378631731
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    Apoptosis: Decrease of Hepatocyte Population in Mice after Hyperthermia (2000)
    Springer
    Bulletin of experimental biology and medicine 130 (2000), S. 912-916 
    Details
    ISSN: 1573-8221
    Keywords: whole-body hyperthermia ; hepatocytes ; alkaline dissociation of tissues ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract hyperthermia caused hemodynamic disorders in the liver and degenerative and necrobiotic changes in hepatocytes of CBA mice. Total hepatocyte count decreased during restitution, this decrease being most pronounced 30 min after exposure. The number of binucleated cells also markedly decreased. The absence of necrotic changes in hepatocytes during the entire restitution period indicated their apoptotic death and elimination by macrophagal resorption. Under these conditions liver regeneration at the cellular level occured mainly via division of binucleated hepatocytes. On the other hand, proliferation of oval cells in the portal zones and their differentiation into hepatocytes were observed at certain stages of reparative regeneration of the liver.
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    URL: http://dx.doi.org/10.1023/A:1015390901689
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    Activity of sympathoadrenal system and myelokaryocyte death during aging in AKR/JY mice (2000)
    Springer
    Bulletin of experimental biology and medicine 129 (2000), S. 519-521 
    Details
    ISSN: 1573-8221
    Keywords: adrenal glands ; bone marrow ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Accelerated bone marrow cell death and activation of the sympathoadrenal system were observed during aging of highly leukemic 2–7-month-old AKR/JY mice compared to that in (CBA/CaLac×AKR/JY)F1 strain. Close correlation was revealed between activity of the sympathoadrenal system and necrotic and apoptotic forms of cell death. This can promote tumor process, because maximum changes in hemopoietic cells occur during advanced stage of the disease.
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    URL: http://dx.doi.org/10.1007/BF02434863
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    Oxidative stress in keratinocytes as an etiopathogenetic factor of psoriasis (2000)
    Springer
    Bulletin of experimental biology and medicine 129 (2000), S. 309-313 
    Details
    ISSN: 1573-8221
    Keywords: psoriasis ; apoptosis ; inflammation ; proliferation ; oxidative stress ; lipid peroxidation ; reactive oxygen species ; redox potential
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract A new etiopathogenetic concept of psoriasis is proposed, which considers psoriasis as a typical inflammatory process characterized by increased antioxidant activity and overexpression of apoptotic receptors. Under these conditions, hyperstimulation of germinative layer cells proliferation dramatically accelerates kerationcyte passage towards apoptotic effect of atmospheric oxygen and its reactive species dooming to death cells with enhanced expression of apoptotic receptors. Oxidative stress of nondifferentiated kerationcytes triggers the formation of defective horny layer, the key mechanism of psoriasis.
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    URL: http://dx.doi.org/10.1007/BF02439252
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    Role of Nitric Oxide in Activation of Human T Lymphocytes Induced by Bacterial Superantigen (2000)
    Springer
    Bulletin of experimental biology and medicine 130 (2000), S. 957-960 
    Details
    ISSN: 1573-8221
    Keywords: human T lymphocytes ; staphylococcal enterotoxin B ; nitric oxide ; proliferation ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The involvement of nitric oxide (NO) in the regulation of human T cell response to bacterial superantigen (staphylococcal enterotoxin B) was studied. It was shown that stimulated T lymphocytes are the main source of NO. This superantigen markedly increased NO production and triggered the proliferative response of mononuclear cells from healthy individuals; the degree of apoptosis was low. In patients with purulent surgical diseases with high spontaneous and induced NO production, superantigen enhanced apoptosis of lymphocytes and induced anergy of T cells to enterotoxins. Increasing the concentration of NO in cultured cells from healthy individuals in the presence of NO donors also stimulated apoptosis and inhibited proliferative activity. These data suggest that NO regulates T lymphocyte response to superantigens. The increased production of NO probably contributes to the development of immunosuppression during bacterial infection.
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    URL: http://dx.doi.org/10.1023/A:1002805605520
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    The Use of Large-Scale cDNA Analysis to Profile Differential Gene Expression in KYSE 410 Human Esophageal Cancer Cells after Irradiation (2000)
    Springer
    Bulletin of experimental biology and medicine 130 (2000), S. 882-885 
    Details
    ISSN: 1573-8221
    Keywords: cDNA analysis ; irradiation ; transcription ; carcinogenesis ; genes ; regulation of cell cycle ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Atlas Human cDNA Expression Array, which includes 588 genes divided into functional classes, was used to study gene expression profiles in KYSE 410 human esophageal cancer cells irradiated in doses of 6 and 18 Gy. Considerable changes in the expression of a number of genes was found, including down-regulation of 3 cell cycle regulators and up-regulation of an apoptosis-related gene. Comparison of the expression profiles and identification of genes were performed with Atlas Vision 3.0 software.
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    URL: http://dx.doi.org/10.1023/A:1015374530823
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    Apoptosis of Cardiomyocytes as Extreme Manifestation of Regeneration and Plastic Insufficiency of Myocardium (2000)
    Springer
    Bulletin of experimental biology and medicine 130 (2000), S. 903-907 
    Details
    ISSN: 1573-8221
    Keywords: anthracycline cardiomyopathy ; regeneration and plastic myocardium insufficiency ; cardiomyocytes ; absolute number of cardiomyocytes ; apoptosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract Alkaline dissociation of the myocardium from rats with modeled anthracycline cardiomyopathy revealed decreased absolute number of cardiomyocytes, disturbances in their intracellular regeneration, although no sings of necrosis were observed. Regeneration and plastic insufficiency of the myocardium due to structural changes in the nuclei and disturbances in myofibril reproduction resulting from selective suppression of synthesis of contractile proteins in the cardiomyocytes leads to the death of up to 30% cardiomyocytes.
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    URL: http://dx.doi.org/10.1023/A:1015386800781
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    Mechanisms for ground-surface fracturing and incipient slope failure associated with the 2001 eruption of Mt. Etna, Italy: analysis of ephemeral field data (2008)
    Elsevier
    Details
    Publication Date: 2020-11-26
    Description: During the July^August 2001 eruption of Mt. Etna development of extensional fractures/faults and grabens accompanied magma intrusion and subsequent volcanic activity. During the first days of the eruption, we performed an analysis of attitude, displacement and propagation of fractures and faults exposed on the ground surface in two sites, Torre del Filosofo and Valle del Leone, located along the same fracture system in the region surrounding the Valle del Bove depression on the eastern flank of Mt. Etna. Fractures and faults formed as the consequence of a shallow intruding dyke system that fed the several volcanic centres developed along the fracture system. The investigated sites differ in slope attitude and in geometrical relationships between fractures and slopes. In particular, the fracture system propagated parallel to the gentle slope (67‡ dip) in the Torre del Filosofo area, and perpendicular to the steep slope (V25‡ dip) in the Valle del Leone area. In the Torre del Filosofo area, slight graben subsidence and horizontal extension of the ground surface by about 3 m were recorded. In the Valle del Leone area, extensional faulting forming a larger and deeper graben with horizontal extension of the ground surface by about 10 m was recorded. For the Valle del Leone area, we assessed a downhill dip of 14‡ for the graben master fault at the structural level beneath the graben where the fault dip shallows. These results suggest that dyke intrusion at Mount Etna, and particularly in the region surrounding the Valle del Bove depression, may be at the origin of slope failure and subsequent slumps where boundary conditions, i.e. geometry of dyke, slope dip and initial shear stress, amongst others, favour incipient failures.
    Description: Published
    Description: 281-294
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: dykes ; extensional fractures ; grabens ; slope failures ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 74
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    Forecasting Lava Flow Hazard during the 2006 Etna Eruption: Using the Magflow Cellular Automata Model (2008)
    Elsevier
    Details
    Publication Date: 2020-11-16
    Description: The MAGFLOW cellular automata model was able to fairly accurately reproduce the time of the lava flow advance during the 2006 Etna eruption leading to very plausible flow predictions. MAGFLOW is intended for use in emergency response situations during an eruption to quickly forecast the lava flow path over some time interval from the immediate future to a long-time forecast. Major discrepancies between the observed and simulated paths occurred in the early phase of the 2006 eruption due to an underestimation of the initial flow rate, and at the time of the overlapping with the 2004-2005 lava flow. Very good representations of the areas likely to be inundated by lava flows were obtained when we adopt a time-varying effusion rate and include the 2004-2005 lava flow field in the Digital Elevation Model (DEM) of topography.
    Description: Published
    Description: 1050-1060
    Description: 5V. Processi eruttivi e post-eruttivi
    Description: JCR Journal
    Description: open
    Keywords: Lava Flow ; Etna volcano ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks ; 05. General::05.01. Computational geophysics::05.01.05. Algorithms and implementation
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  • 75
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    Proximal tephra hazards: Recent eruption studies applied to volcanic risk in the Auckland volcanic field, New Zealand (2007)
    Elsevier
    Details
    Publication Date: 2020-11-30
    Description: Auckland, New Zealand is unique in being a metropolitan area built on an active volcanic field. Despite the small size and intensity of Auckland eruptions, the risk from tephra fall is high because of the high density of buildings and lifelines. The nature of this threat can be evaluated by comparisons with historical Strombolian and Hawaiian eruptions, which have occurred in non-populated areas. Cone-building phases of such eruptions are typically protracted, i.e., weeks to months in duration, prolonging the period during which emergency managers will have to fine tune mitigation for numerous parameters such as fluctuations in intensity and wind shifts. Rapid cone growth during future eruptions will define a region of some 30 to 100 ha where complete destruction will occur on a time scale of hours. The cost of this destruction is likely to range between NZ$200M and NZ$1.4B (ca. US$130M to US$900M). Beyond this, we have modeled the cumulative long-term effect of the build-up of a downwind blanket of lapilli and ash by estimating accumulation rates for three phases of the 1959 Kīlauea Iki eruption in Hawaii. The effect of changing wind direction was evaluated using low-level wind data from Auckland. These results show that intervals between 4 and 100 h will lapse before onset of significant damage to buildings.
    Description: Published
    Description: 138-149
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: tephra hazard ; Auckland volcanic field ; cone growth ; tephra fall ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 76
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    The role of extensional structures on experimental calderas and resurgence (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The structure and shape of collapses and resurgences is often controlled by pre-existing discontinuities, such as normal faults in rift zones. In order to study the role of extensional structures on collapse and resurgence, we used analogue models. Dry sand simulated the brittle crust; silicone, located at the base of the sand-pack, simulated magma. In the experiments, regional extension pre-dated collapse or resurgence, forming normal faults in a grabenlike structure; the graben was filled with additional sand, simulating post-rift deposits. A piston then moved the silicone downward or upward, inducing collapse or resurgence within the previously deformed sand. The collapses showed an ellipticity (length of minor axis/length of major axis) between 0.8 and 0.9, with the major axis parallel to the extension direction. The partial reactivation of the pre-existing normal faults was observed during the development of the caldera reverse faults, which, conversely to what was expected (from experiments without preexisting extension), became partly inward dipping. Resurgence showed an elongation of the uplifted part, with the main axis perpendicular to the extension direction. At depth, pre-existing normal faults were partly reactivated by the reverse faults formed during resurgence; these locally became outward dipping normal faults. A total reactivation of pre-existing faults was also observed during resurgence. The experiments suggest that the observed elongation of calderas and resurgences is the result of the reactivation of pre-existing structures during differential uplift. Such a reactivation is mainly related to the loss in the coefficient of friction of the sand. The results suggest that elliptic calderas and resurgences in nature may develop even from circular magma chambers.
    Description: Published
    Description: 199-217
    Description: partially_open
    Keywords: Extensional structures ; Caldera ; Resurgence ; Analogue models ; Reactivation ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 77
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    Numerical simulation of pyroclastic density currents on Campi Flegrei topography: a tool for statistical hazard estimation. (2006)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We describe a numerical simulation of both concentrated and dilute gravity-driven pyroclastic flows on a digital topographic model of the Campi Flegrei volcanic field. Families of numerical flows are generated by sampling a multi-dimensional matrix of vent coordinates, flow properties and dynamical parameters within a wide range of values. Hazard maps are constructed from the data base of simulated flows, using a mixed deterministic^statistical approach. The set of probable vents covers the area of recent eruptions. Results show the key role of topography in controlling the flow dispersion. The maximum hazard appears to be the NE sector of the caldera. Flows in the eastern sector, including the city of Naples, are shown to be efficiently hindered by the Posillipo and Camaldoli hills at the caldera borders, thus reducing the hazard. The results represent the first physically based estimate of hazard from pyroclastic flows in this densely populated area, and can be used for civil defence purposes.
    Description: Published
    Description: 1-14
    Description: partially_open
    Keywords: Campi flegrei ; calderas ; pyroclastic flows ; hazard maps ; 05. General::05.01. Computational geophysics::05.01.04. Statistical analysis ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 78
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    A quantitative model for volcanic hazard assessment (2007)
    Springer
    Details
    Publication Date: 2017-04-04
    Description: Volcanic hazard assessment is a basic ingredient for risk-based decision-making in land-use planning and emergency management. Volcanic hazard is defined as the probability of any particular area being affected by a destructive volcanic event within a given period of time (Fournier d’Albe 1979). The probabilistic nature of such an important issue derives from the fact that volcanic activity is a complex process, characterized by several and usually unknown degrees of freedom that are often linked by nonlinear relationships (e.g. Bak et al. 1988). Except in sporadic cases, the result of this complexity is an intrinsic, and perhaps unavoidable, unpredictability of the time evolution of the volcanic system from a deterministic point of view.
    Description: Published
    Description: open
    Keywords: model ; volcanic risk ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book
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  • 79
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    BET_EF: a probabilistic tool for long- and short-term eruption forecasting (2007)
    Springer
    Details
    Publication Date: 2017-04-04
    Description: The main purpose of this paper is to introduce a Bayesian event tree model for eruption forecasting (BET EF). The model represents a flexible tool to provide probabilities of any specific event at which we are interested in, by merging all the relevant available information, such as theoretical models, a priori beliefs, monitoring measures, and any kind of past data. BET EF is based on a Bayesian procedure and it relies on the fuzzy approach to manage monitoring data. The method deals with short- and long-term forecasting, therefore it can be useful in many practical aspects, as land use planning, and during volcanic emergencies. Finally, we provide the description of a free software package that provides a graphically supported computation of short- to long-term eruption forecasting, and a tutorial application to the recent MESIMEX exercise at Vesuvius.
    Description: Published
    Description: on line first
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: partially_open
    Keywords: Eruption forecasting ; Long- and short-term volcanic hazard ; Bayesian inference ; Event tree ; Fuzzy sets ; MESIMEX ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 80
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    Seismic hazard assessment at Mt. Vesuvius: Maximum expected magnitude (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This paper deals with the problem of seismicity at Mt. Vesuvius with a view to providing an estimation of the maximum expected earthquake. Integrated analysis of both historical and current seismicity as well as the geological conditions of Vesuvius and the surrounding areas show that seismogenetic structures may fall within the crater axis and at the boundaries of the volcanic complex. While activation of the whole seismogenetic volume detected by seismicity in the past 30 years would indicate a total seismic moment of Mo = 7.1E+ 15 Nm for a magnitude M = 4.5, knowledge of the area's geological structure suggests faulting surfaces of about 32 km2 with an associated magnitude of M = 5.4. The areas of maximum expected damage differ according to the orientation of the hypothesized structure. Analysis of geological and geophysical data and the damage associated to the AD 62 earthquake shows that the prevailing directions in the faulting planes are NE–SW in the eastern sector of the volcanic complex, and roughly WNW–ESE in the southern part of the volcano along the coast. Comparison of instrumental seismicity and historical data reveals two significantly different energy levels: a lower earthquake level with Mmax = 4.5, corresponding to current seismicity and that which accompanied volcanic activity in the eruptive period from 1631–1944; an upper level with Mmax = 5.4, represented by the AD 62 earthquake. The two levels correspond to two stress states and different seismogenetic structures.
    Description: Published
    Description: 139-149
    Description: 3.6. Fisica del vulcanismo
    Description: 3.10. Sismologia storica e archeosismologia
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 5.1. TTC - Banche dati e metodi macrosismici
    Description: JCR Journal
    Description: reserved
    Keywords: Mt. Vesuvius ; seismic hazard ; historical seismicity ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 81
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    Hydrothermal fluid circulation and its effect on caldera unrest (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This paper focuses on the role that hydrothermal systems may play in caldera unrest. Changes in the fluid chemistry, temperature, and discharge rate of hydrothermal systems are commonly detected at the surface during volcanic unrest, as hydrothermal fluids adjust to changing subsurface conditions. Geochemical monitoring is carried out to observe the evolving system conditions. Circulating fluids can also generate signals that affect geophysical parameters monitored at the surface. Effective hazard evaluation requires a proper understanding of unrest phenomena and correct interpretation of their causes. Physical modeling of fluid circulation allows quantification of the evolution of a hydrothermal system, and hence evaluation of the potential role of hydrothermal fluids during caldera unrest. Modeling results can be compared with monitoring data, and then contribute to the interpretation of the recent caldera evolution. This paper: 1) describes the main features of hydrothermal systems; 2) briefly reviews numerical modeling of heat and fluid flow through porous media; 3) highlight the effects of hydrothermal fluids on unrest processes; and 4) describes some model applications to the Phlegrean Fields caldera. Simultaneous modeling of different independent parameters has proved to be a powerful tool for understanding caldera unrest. The results highlight the importance of comprehensive conceptual models that incorporate all the available geochemical and geophysical information, and they also stress the need for high-quality, multi-parameter monitoring and modeling of volcanic activity.
    Description: Accepted
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: open
    Keywords: hydrothermal activity ; caldera unrest ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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    Type: book chapter
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  • 82
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    Volumetric observations during paroxysmal eruptions at Mount Etna: pressurized drainage of a shallow chamber or pulsed supply? (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The October 17 to November 5, 1999, eruption of Mount Etna’s Bocca Nuova crater emplaced a V15U106 m3 flow field. The eruption was characterized by 11 paroxysmal events during which intense Strombolian and lava fountain activity fed vigorous channelized PaPa flows at eruption rates of up to 120 m3 s31. Each paroxysm lasted between 75 and 450 min, and was separated by periods of less intense Strombolian activity and less vigorous (610 m3 s31) effusion. Ground-based, satellite- and model-derived volumetric data show that the eruption was characterized by two periods during which eruption rates and cumulative volume showed exponential decay. This is consistent with a scenario whereby the system was depressurized during the first eruptive period (October 17^23), repressurized during an October 24 pause, and then depressurized again during the second period (October 25^28). The imbalance between the erupted and supplied volumes mean that the two periods involved the collection of 1.5^5.7U106 m3 and 1.2^ 3.6U106 m3, respectively, or an increase in the time-averaged supply to 11.6^13.6 m3 s31 and 12.5^14.9 m3 s31. Two models are consistent with the observed episodic fountaining, derived volumetric trends and calculated volume imbalance: a magma collection model and a pulsed supply model. In the former case, depressurization of a shallow reservoir cause the observed volumetric trends and foam collapse at the reservoir roof powers fountaining. In the pulsing case, variations in magma flux account for pressurization^depressurization and supply the excess volume. Increases in rise rate and volatile flux, coupled with rapid exsolution during ascent, trigger fountaining. Limiting equations that define critical foam layer volumes and magma rise rates necessary for Hawaiian-style fountaining favor the latter model.
    Description: Published
    Description: 79-95
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Etna ; lava fountaining ; eruption rates ; lava channel ; foam layers ; rise rates ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.05. Rheology ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.02. Exploration geophysics::04.02.05. Downhole, radioactivity, remote sensing, and other methods ; 04. Solid Earth::04.02. Exploration geophysics::04.02.07. Instruments and techniques ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.04. Thermodynamics ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 83
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    Vent conditions for expected eruptions at Vesuvius (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Determining consistent sets of vent conditions for next expected eruptions at Vesuvius is crucial for the simulation of the sub-aerial processes originating the volcanic hazard and the eruption impact. Herewerefer to the expected eruptive scales and conditions defined in the frame of the EC Exploris project, and simulate the dynamics of magma ascent along the volcanic conduit for sub-steady phases of next eruptions characterized by intensities of the Violent Strombolian (VS), Sub-Plinian 2 (SP2), and Sub-Plinian 1 (SP1) scale. Sets of conditions for the simulations are determined on the basis of the bulk of knowledge on the past history of Vesuvius [Cioni, R., Bertagnini, A., Santacroce, R., Andronico, D., Explosive activity and eruption scenarios at Somma–Vesuvius (Italy): towards a new classification scheme. Journal of Volcanology and Geothermal Research, this issue.]. Volatile contents (H2O and CO2) are parameterized in order to account for the uncertainty in their expected amounts for a next eruption. In all cases the flow in the conduit is found to be choked, with velocities at the conduit exit or vent corresponding to the sonic velocity in the two-phase non-equilibrium magmatic mixture. Conduit diameters and vent mixture densities are found to display minimum overlapping between the different eruptive scales, while exit gas and particle velocities, as well as vent pressures, largely overlap. Vent diameters vary from as low as about 5 m for VS eruptions, to 35–55 m for the most violent SP1 eruption scale. Vent pressures can be as low as less than 1 MPa for the lowest volatile content employed of 2 wt.% H2O and no CO2, to 7–8 MPa for highest volatile contents of 5 wt.% H2O and 2 wt.% CO2 and large eruptive scales. Gas and particle velocities at the vent range from 100–250 m/s, with a tendency to decrease, and to increase the mechanical decoupling between the phases, with increasing eruptive scale. Except for velocities, all relevant vent quantities are more sensitive to the volatile content of the discharged magma for the highest eruptive scales considered.
    Description: Published
    Description: 359-365
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Vesuvius ; Numerical simulations ; Vent conditions ; Volcanic hazard ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 84
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    Emergency planning and mitigation at Vesuvius: A new evidence-based approach (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Disasters from explosive volcanic eruptions are infrequent and experience in emergency planning and mitigation for such events remains limited. The need for urgently developing more robust methods for risk assessment and decision making in volcanic crises has become increasingly apparent as world populations continue to expand in areas of active explosive volcanism. Nowhere is this more challenging than at Vesuvius, Italy, with hundreds of thousands of people living on the flanks of one of the most dangerous volcanoes in the world. We describe how a new paradigm, evidence-based volcanology, has been applied in EXPLORIS to contribute to crisis planning and management for when the volcano enters its next state of unrest, as well as in long-term land-use planning. The analytical approach we adopted enumerates and quantifies all the processes and effects of the eruptive hazards of the volcano known to influence risk, a scientific challenge that combines field data on the vulnerability of the built environment and humans in past volcanic disasters with theoretical research on the state of the volcano, and including evidence from the field on previous eruptions as well as numerical simulation modelling of eruptive processes. Formal probabilistic reasoning under uncertainty and a decision analysis approach have provided the basis for the development of an event tree for a future range of eruption types with probability paths and hypothetical casualty outcomes for risk assessment. The most likely future eruption scenarios for emergency planning were derived from the event tree and elaborated upon from the geological and historical record. Modelling the impacts in these scenarios and quantifying the consequences for the circumvesuvian area provide realistic assessments for disaster planning and for showing the potential risk–benefit of mitigation measures, the main one being timely evacuation, but include for consideration protecting buildings against dilute, low dynamic pressure surges, and temporary roof supports in the most vulnerable buildings, as well as hardening infrastructure and lifelines. This innovative work suggests that risk-based methods could have an important role in crisis management at cities on volcanoes and small volcanic islands.
    Description: Published
    Description: 454-473
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: open
    Keywords: planning ; emergency ; volcano ; eruption ; mitigation ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 85
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    Sources of ground movement at Vesuvius before the AD 79 eruption: Evidence from contemporary accounts and archaeological studies (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Historical sources have recorded earthquake shocks, their effects and difficulties that local inhabitants experienced before the AD 79 Pompeii eruption. Archaeological studies pointed out the effects of such seismicity, and have also evidenced that several water crises were occurring at Pompeii in that period. Indeed numerous sources show that, at the time of eruption, and probably some time before, the civic aqueduct, having ceased to be supplied by the regional one, was out of order and that a new one was being built. Since Roman aqueducts were usually built with a recommended minimum mean slope of 20 cm/km and Pompeii's aqueduct sloped from the nearby Apennines toward the town, this slope could have been easily cancelled by uplift that occurred in the area even if this was only moderate. For the crustal deformations a volcanic origin is proposed and a point source model is used to explain the observations. Simple analysis of the available data suggests that the ground deformations were caused by a b2 km3 volumetric change at a depth of ∼8 km that happened over the course of several decades.
    Description: Published
    Description: 959–970
    Description: 5.1. TTC - Banche dati e metodi macrosismici
    Description: JCR Journal
    Description: reserved
    Keywords: Vesuvius ; ground deformation ; seismicity ; stress changes ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.06. Seismology::04.06.05. Historical seismology ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 86
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    Insight on recent Stromboli eruption inferred from terrestrial and satellite ground deformation measurements (2009)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The multi-parametric permanent system (tilt and GPS networks, robotized geodetic station) for monitoring ground deformation at Stromboli volcano was set up in the 1990s and later greatly improved during the effusive event of 2002–2003. Unlike other volcanoes, e.g. Mt. Etna, the magnitude of ground deformation signals of Stromboli is very small and through the entire period of operation of the monitoring system, only two major episodes of deformation, in 1994–1995 and 2000, which did not lead to an eruption but rather pure intrusion, were measured. Similarly to the 2002–2003 eruption, no important deformations were detected in the months before the 2007 eruption. However, unlike the 2002–2003 eruption, GPS and tilt stations recorded a continuous deflation during the entire 2007 eruption, which allowed us to infer a vertical elongated prolate ellipsoidal source, centered below the summit craters at depth of about 2.8 km b.s.l. Due to its geometry and position, this source simulates an elongated plumbing system connecting the deeper LP magma storage (depth from 5 to 10 km) with the HP shallower storage (0.8–3 km), both previously identified by petrologic and geochemical studies. This result represents the first contribution of geophysics to the definition of the plumbing system of Stromboli at intermediate depth. Finally, no deformation due to the plumbing system was measured for a long time after the end of the eruption. Meanwhile, the new terrestrial geodetic monitoring system installed within the Sciara del Fuoco, on the lava fan formed during the eruption, indicated that during the first months after the end of the eruption the ground velocity progressively decreased in time, suggesting that part of the deformation was due to the thermal contraction of the lava flow.
    Description: Published
    Description: 172-181
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: JCR Journal
    Description: reserved
    Keywords: Stromboli ; Ground Deformation ; source modelling ; flank instability ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.03. Geodesy::04.03.09. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 87
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    Hazards from pyroclastic density currents at Mt. Etna (Italy) (2009)
    Elsevier
    Details
    Publication Date: 2017-04-03
    Description: Despite the recent recognition of Mount Etna as a periodically violently explosive volcano, the hazards from various types of pyroclastic density currents (PDCs) have until now received virtually no attention at this volcano. Large-scale pyroclastic flows last occurred during the caldera-forming Ellittico eruptions, 15–16 ka ago, and the risk of them occurring in the near future is negligible. However, minor PDCs can affect much of the summit area and portions of the upper flanks of the volcano. During the past ~ 20 years, small pyroclastic flows or base-surge-like vapor and ash clouds have occurred in at least 8 cases during summit eruptions of Etna. Four different mechanisms of PDC generation have been identified during these events: (1) collapse of pyroclastic fountains (as in 2000 and possibly in 1986); (2) phreatomagmatic explosions resulting from mixing of lava with wet rock (2006); (3) phreatomagmatic explosions resulting from mixing of lava with thick snow (2007); (4) disintegration of the unstable flanks of a lava dome-like structure growing over the rim of one of the summit craters (1999). All of these recent PDCs were of a rather minor extent (maximum runout lengths were about 1.5 km in November 2006 and March 2007) and thus they represented no threat for populated areas and human property around the volcano. Yet, events of this type pose a significant threat to the lives of people visiting the summit area of Etna, and areas in a radius of 2 km from the summit craters should be off-limits anytime an event capable of producing similar PDCs occurs. The most likely source of further PDCs in the near future is the Southeast Crater, the youngest, most active and most unstable of the four summit craters of Etna, where 6 of the 8 documented recent PDCs originated. It is likely that similar hazards exist in a number of volcanic settings elsewhere, especially at snow- or glacier-covered volcanoes and on volcano slopes strongly affected by hydrothermal alteration.
    Description: Published
    Description: 148-160
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Pyroclastic density currents ; Mt. Etna ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 88
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    Gas hazard assessment in a densely inhabited area of Colli Albani Volcano (Cava dei Selci, Roma) (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The northwestern flank of the Colli Albani, a Quaternary volcanic complex near Rome, is characterised by high CO2 values and Rn activities in the groundwater and by the presence of zones with strong emission of gas from the soil. The most significant of these zones is Cava dei Selci where many houses are located very near to the gas emission site. The emitted gas consists mainly of CO2 (up to 98 vol) with an appreciable content of H2S (0.8). The He and C isotopic composition indicates, as for all fluids associated with the Quaternary Roman and Tuscany volcanic provinces, the presence of an upper mantle component contaminated by crustal fluids associated with subducted sediments and carbonates. An advective CO2 flux of 37 tons/day has been estimated from the gas bubbles rising to the surface in a small drainage ditch and through a stagnant water pool, present in the rainy season in a topographically low central part of the area. A CO2 soil flux survey with an accumulation chamber, carried out in February-March 2000 over a 12 000 m2 surface with 242 measurement points, gave a total (mostly conductive) flux of 61 tons/day. CO2 soil flux values vary by four orders of magnitude over a 160-m distance and by one order of magnitude over several metres. A fixed network of 114 points over 6350 m2 has been installed in order to investigate temporal flux variations. Six surveys carried out from May 2000 to June 2001 have shown large variations of the total CO2 soil flux (8/25 tons/day). The strong emission of CO2 and H2S, which are gases denser than air, produces dangerous accumulations in low areas which have caused a series of lethal accidents to animals and one to a man. The gas hazard near the houses has been assessed by continuously monitoring the CO2 and H2S concentration in the air at 75 cm from the ground by means of two automatic stations. Certain environmental parameters (wind direction and speed; atm P, T, humidity and rainfall) were also continuously recorded. At both stations, H2S and CO2 exceeded by several times the recommended concentration thresholds. The highest CO2 and H2S values were recorded always with wind speeds less than 1.5 m/s, mostly in the night hours. Our results indicate that there is a severe gas hazard for people living near the gas emission site of Cava dei Selci, and appropriate precautionary and prevention measures have been recommended both to residents and local authorities.
    Description: - GNV funded research project Gas Hazard of Colli Albani
    Description: Published
    Description: 81^94
    Description: partially_open
    Keywords: Colli Albani ; CO2 flux ; H2S ; gas hazard ; 01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry ; 04. Solid Earth::04.08. Volcanology::04.08.01. Gases ; 04. Solid Earth::04.08. Volcanology::04.08.02. Experimental volcanism ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.01. Geochemical data ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 89
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    Magma degassing and crystallization processes during eruptions of high-risk Neapolitan-volcanoes: Evidence of common equilibrium rising processes in alkaline magmas (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Compositional, textural and experimental data on products from explosive and effusive eruptions of Neapolitan volcanoes (Campi Flegrei and Somma-Vesuvio) allow us to constrain degassing and fragmentation conditions during eruptions of alkaline magmas. Significant differences in compositional and textural features have been recognized between lavas, scoria and pumice resulting respectively from effusive, moderately and extremely explosive eruptions. Pumice samples have highly-vesicular glassy matrix, low microlite number density and moderate to high water content. Crystal Size Distributions (CSD) are steep with high intercept values; the narrow microlite size range indicates single nucleation event. Scoria products are characterized by moderate vesicularity and water content. They have high number density of microlites which are bimodal in size. CSD show distinct inflections that are explained as two crystal populations growing in distinct time. Lava samples generally have low vesicularities, moderate to high microcrystalline groundmass and low glass water content. The comparison between textural and compositional features of natural rocks with samples obtained by decompression experiments allows us to conclude that degassing processes during magma ascent occurs in near-equilibrium conditions even at high decompression rate. Moderate to long magma rise times, calculated in the order of a few days, produce opendegassing responsible formoderately explosive to effusive activity. Shortmagma rise times, calculated in the order of a fewhours, result in closed-system degassing that allow explosive fragmentation when the volume of growing bubble reaches a fixed threshold. Vesicularity and water content measured on matrix glass of pumice indicate that this process occurs at pressure of 10–30 MPa. In these conditions, degassing, fragmentation and in turn the eruptive style is strongly influenced by initial conditions in themagma chamber (volatile content, temperature, pressure) instead of decompression rate, in contrast with that observed for rhyolitic melts. These differences have important consequences in terms of volcanic hazards and risk. The low-viscosity alkaline magma is able tomaintain efficient degassing even during the final stage of magma ascent, favoring, in the case of closed-system, fragmentation and explosive activity.
    Description: Published
    Description: 164-181
    Description: reserved
    Keywords: Campi Flegrei and Somma-Vesuvio ; explosive eruptions ; vesiculation ; crystallization ; degassing ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 90
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    Modeling of the 2001 lava flow at Etna volcano by a Cellular Automata approach (2007)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The 2D Cellular Automata model, MAGFLOW, simulates lava flows and an algorithm based on the Monte Carlo approach solves the anisotropic flow direction problem. The model was applied to reproduce a lava flow formed during the 2001 Etna eruption. This eruption provided the opportunity to verify the ability of MAGFLOW to simulate the path of lava flows which was made possible due to the availability of the necessary data for both modeling and subsequent validation. MAGFLOW reproduced quite accurately the spread of flow. A good agreement was highlighted between the simulated and observed length on steep slopes, whereas the area covered by the lava flow tends to be overestimated. The major inconsistencies found in the comparison between simulated and observed lava flow due to neglecting the effects of ephemeral vent formation.
    Description: Published
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: open
    Keywords: Lava flow ; Etna volcano ; Numerical simulation ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.01. Computational geophysics::05.01.02. Cellular automata, fuzzy logic, genetic alghoritms, neural networks
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  • 91
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    Oscillation-induced mobility of flows of rock fragments with quasi-rigid plugs in rectangular channels with frictional walls: A hypothesis (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: We present here a new hypothesis to explain the high mobility of same rapid mass movements of rock fragments. We suggest that oscillations of flows with a quasi-rigid plug can result in reduction of their apparent coefficient of friction. This coefficient is computed as the ratio between drop in elevation and horizontal distance of travel. In our model, the effective friction during a downhill journey is a combination of the friction forces acting on the plug during the ascending and descending parts of its slope-normal oscillations. As a consequence of oscillations, the decreased contact with ground surface reduces the apparent coefficient of friction. Channel lateral surfaces can also support a portion of plug weight giving another contribution in the reduction of this coefficient. The support of lateral surfaces requires a relatively narrow channel such as a gully or the presence of levees whereas the reduced basal contact can be important also in larger channels that do not provide lateral support. We suggest that slope-normal oscillations are generated by ground asperities. The true coefficients of friction are larger than the apparent one because they account energetically for the oscillations that reduce basal contact. Thus we can say that our model is able to explain long runout distances as long as the energy dissipated by oscillations is accounted for by the true coefficients of friction that enter the calculations. Field and experimental investigation of the several ideas discussed in this paper constitutes important aspects of future research that will improve the understanding of granular flows mobility.
    Description: In press
    Description: 3.6. Fisica del vulcanismo
    Description: JCR Journal
    Description: reserved
    Keywords: Pyroclastic flows ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 92
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    Intrusion of eccentric dikes: The case of the 2001 eruption and its role in the dynamics of Mt. Etna volcano (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The 2001 eruption represents one of the most studied events both from volcanological and geophysical point of view on Mt. Etna. This eruption was a crucial event in the recent dynamic of the volcano, marking the passage from a period (March 1993 – June 2001) of moderate stability with slow, continuous flank sliding and contemporaneous summit eruptions, to a period (July 2001 to present) of dramatically increased flank deformations and flank eruptions. We show new GPS data and high precision relocation of seismicity in order to demonstrate the role of the 2001 intrusive phase in this change of the dynamic regime of the volcano. GPS data consist of two kinematic surveys carried out on 12 July, a few hours before the beginning of the seismic swarm, and on 17 July, just after the onset of eruptive activity. A picture of the spatial distribution of the sin-eruptive seismicity has been obtained using the HypoDD relocation algorithm based on the double-difference (DD) technique. Modeling of GPS measurements reveal a southward motion of the upper southern part of the volcano, driven by a NNW-SSE structure showing mainly left-lateral kinematics. Precise hypocenter location evidences an aseismic zone at about sea level, where the magma upraise was characterized by a much higher velocity and an abrupt westward shift, revealing the existence of a weakened or ductile zone. These results reveal how an intrusion of a dike can severely modify the shallow stress field, triggering significant flank failure. In 2001, the intrusion was driven by a weakened surface, which might correspond to a decollement plane of the portion of the volcano affected by flank instability, inducing an additional stress testified by GPS measurements and seismic data, which led to an acceleration of the sliding flanks.
    Description: In press
    Description: 1.1. TTC - Monitoraggio sismico del territorio nazionale
    Description: 1.3. TTC - Sorveglianza geodetica delle aree vulcaniche attive
    Description: 1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attive
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: 4.2. TTC - Scenari e mappe di pericolosità sismica
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: 4.4. Scenari e mitigazione del rischio ambientale
    Description: JCR Journal
    Description: reserved
    Keywords: Stress release ; Dike ; Volcano-tectonics ; Flank instability ; Mount Etna ; Instrumental monitoring ; 04. Solid Earth::04.01. Earth Interior::04.01.99. General or miscellaneous ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.99. General or miscellaneous ; 04. Solid Earth::04.03. Geodesy::04.03.06. Measurements and monitoring ; 04. Solid Earth::04.03. Geodesy::04.03.07. Satellite geodesy ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.01. Earthquake geology and paleoseismology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.06. Seismology::04.06.99. General or miscellaneous ; 04. Solid Earth::04.06. Seismology::04.06.03. Earthquake source and dynamics ; 04. Solid Earth::04.06. Seismology::04.06.04. Ground motion ; 04. Solid Earth::04.06. Seismology::04.06.08. Volcano seismology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.02. Geodynamics ; 04. Solid Earth::04.07. Tectonophysics::04.07.05. Stress ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.07. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions
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  • 93
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    Structural features of the 2007 Stromboli eruption (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: On 27 February 2007, two NE–SW and NNW–SSE dike-fed effusive vents opened to the North (at 650 and 400 m above sea level, asl) of the summit craters at Stromboli, forming a fissure parallel to the inner walls of the Sciara del Fuoco (SdF) sector collapse depression. The formation of these vents was soon followed by rapid subsidence of the summit crater area. This partly obstructed the central conduit, temporarily choking the fissure and increasing the deformation of the upper part of SdF. The reactivation of the NNW–SSE vent and the opening of a new vent located at 500 m asl, fed by a second dike, released the internal pressure and surface deformation ceased. The eruption then continued again from the 400 m vent, after a summit explosion on 15 March, until ending in early April after a progressive decrease of magma output. Repeated NE–SW dike intrusions have occurred in recent years, close to the upper SE limit of the SdF. In that zone, named Bastimento, the eruptive fractures traced the discontinuities that borders the SdF, increasing the risk of triggering new sector collapse. Whereas the NE–SW trending structures lie along the regional volcanostructural trend of the Aeolian arc through Stromboli, the NNW–SSE vents are oblique to this trend and may be controlled by the anomalous stress field within the unstable flank of the SdF. Another fundamental aspect of the 2007 eruption is the collapse of the central conduit, due to the rapid and deep magma drainage linked to the opening of the 400 m vent. The intrusion of dikes and development of flank vents during the 2007 eruption could possibly have triggered catastrophic landslides and related tsunami or eruptive paroxysms, but the opening of new effusive vents released the internal pressures, diminishing the hazard.
    Description: In press
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: 3.2. Tettonica attiva
    Description: 3.5. Geologia e storia dei sistemi vulcanici
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: 2007 Stromboli eruption ; Dike-fed vent ; Volcano-Tectonics ; Conduit collapse ; Flank instability ; 04. Solid Earth::04.04. Geology::04.04.99. General or miscellaneous ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.07. Tectonophysics::04.07.99. General or miscellaneous ; 04. Solid Earth::04.07. Tectonophysics::04.07.07. Tectonics ; 04. Solid Earth::04.07. Tectonophysics::04.07.08. Volcanic arcs ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
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  • 94
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    An exceptional case of endogenous lava dome growth (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: During an eruption at the Bocca Nuova, one of the summit craters of Mt. Etna, in October-November 1999 a part of the crater floor near its WNW rim was uplifted to form a dome-shaped feature that consisted of older lava and pyroclastics filling the crater. This endogenous dome grew rapidly over the crater rim, thus being perched precariously over the steep outer slope of the Bocca Nuova, and near-continuous collapse of its steep flanks generated swiftly moving pyroclastic avalanches over a period of several hours. These avalanches advanced at speeds of 10-20 m s-1 and extended up to 0.7 km from their source on top of lavas emplaced immediately before. Their deposits were subsequently covered by lava flows that issued from vents below the front of the dome and from the Bocca Nuova itself. Growth of the dome was caused by the vertical intrusion of magma in the marginal W part of the crater, which deformed and uplifted previously emplaced, still hot and plastically deformable eruptive products filling the crater. The resulting avalanches had all characteristics of pyroclastic flows spawned by collapse of unstable flanks of lava domes, but in this case the magma involved was of mafic (hawaiitic) composition and would have, under normal circumstances, produced fluid lava flows. The formation of the dome and the generation of the pyroclastic avalanches owe their occurrence to the rheological properties of the eruptive products filling the crater, which were transformed into the dome, and to the morphological configuration of the Bocca Nuova and its surroundings. The density contrast between successive erupted products may also have played a role. Although events of this type are to be considered exceptional at Etna, their recurrence might represent a serious hazard to visitors to the summit area.
    Description: Published
    Description: 115-128
    Description: 1.5. TTC - Sorveglianza dell'attività eruttiva dei vulcani
    Description: JCR Journal
    Description: reserved
    Keywords: Mt. Etna ; Bocca Nuova ; endogenous lava dome ; pyroclastic avalanches ; magma ascent ; 04. Solid Earth::04.08. Volcanology::04.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 05. General::05.08. Risk::05.08.99. General or miscellaneous
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  • 95
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    Hydrothermal Fluid Circulation and its Effect on Caldera Unrest (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This paper focuses on the role that hydrothermal systems may play in caldera unrest. Changes in the fluid chemistry, temperature, and discharge rate of hydrothermal systems are commonly detected at the surface during volcanic unrest, as hydrothermal fluids adjust to changing subsurface conditions. Geochemical monitoring is carried out to observe the evolving system conditions. Circulating fluids can also generate signals that affect geophysical parameters monitored at the surface. Effective hazard evaluation requires a proper understanding of unrest phenomena and correct interpretation of their causes. Physical modeling of fluid circulation allows quantification of the evolution of a hydrothermal system, and hence evaluation of the potential role of hydrothermal fluids during caldera unrest. Modeling results can be compared with monitoring data, and then contribute to the interpretation of the recent caldera evolution. This paper: 1) describes the main features of hydrothermal systems; 2) briefly reviews numerical modeling of heat and fluid flow through porous media; 3) highlight the effects of hydrothermal fluids on unrest processes; and 4) describes some model applications to the Phlegrean Fields caldera. Simultaneous modeling of different independent parameters has proved to be a powerful tool for understanding caldera unrest. The results highlight the importance of comprehensive conceptual models that incorporate all the available geochemical and geophysical information, and they also stress the need for high-quality, multi-parameter monitoring and modeling of volcanic activity.
    Description: Published
    Description: 393-416
    Description: 3.6. Fisica del vulcanismo
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: reserved
    Keywords: hydrothermal fluids ; unrest ; modeling ; caldera ; monitoring ; volcanic hazard ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 96
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    Evaluating explosive eruption risk at European volcanoes (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: No Abstract
    Description: Published
    Description: V-IX
    Description: 4.3. TTC - Scenari di pericolosità vulcanica
    Description: JCR Journal
    Description: reserved
    Keywords: Rischio Vulcanico ; Exploris ; Vulcani esplosivi ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 97
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    Recicling and “re-hydration” of degassed magma inducing transient dissolution/crystallization events at Stromboli (Italy) (2008)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: Intrusive degassing and recycling of degassed and dense magma at depth have been proposed for a long time at Stromboli. The brief explosive event that occurred at the summit craters on 9 January 2005 threw out bombs and lapilli that could be good candidates to illustrate recycling of shallow degassed magma at depth. We present an extensive data set on both the textures and the mineral, bulk rock and glassy matrix chemistry of the “9 Jan” products. The latter have the common shoshonitic–basaltic bulk composition of lavas and scoriae issued from typical strombolian activity. In contrast they differ by the heterogeneous chemistry of their matrix glasses and their crystal textures that testify to crystal dissolution event(s) just prior magma crystallization upon ascent and eruption. Comparison between mineral paragenesis of the natural products and experimental phase equilibria suggest water-induced magma re-equilibration. We propose that mineral dissolution is related to water enrichment of the recycled degassed magma, via differential gas bubble transfer and to some extents its physical mixing with volatile-rich magma blobs. However, all these features illustrate transient processes. Even though evidence of mineral dissolution is ubiquitous at Stromboli, its effect on the bulk magma chemistry is minor because of the subtle interplay between mineral dissolution and crystallization in magmas having comparable bulk chemistry.
    Description: Published
    Description: 325-336
    Description: JCR Journal
    Description: reserved
    Keywords: mineral dissolution ; magma chemistry ; volatiles ; trace elements ; Stromboli ; 04. Solid Earth::04.04. Geology::04.04.05. Mineralogy and petrology ; 04. Solid Earth::04.08. Volcanology::04.08.03. Magmas ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
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  • 98
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    The buried caldera of Misti volcano, Peru, revealed by combining a self-potential survey with elliptic Fourier function analysis of topography (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: This survey proposes a new approach to identify buried caldera boundaries of a volcanic cone, combining (1) a systematic elliptic Fourier functions (EFF) analysis on the contour lines based on the external shape of the edifice with (2) self-potential (SP) measurements on volcano flanks. The methodology of this approach is to investigate the relationships between (1) vertical morphological changes inferred from EFF analysis and (2) lateral lithological transition inside the edifice inferred from SP/elevation gradients. The application of these methods on Misti volcano in southern Peru displays a very good correlation. The three main boundaries evidenced by hierarchical cluster analysis on the contour lines coincide with the two main boundaries characterised by SP signal and with a secondary SP signature related with a summit caldera. In order to explain these results showing a very good correlation between morphologic and lithologic changes as function of elevation, caldera boundaries have been suggested. The latter would be located at an average elevation of (1) 4350–4400 m, (2) 4950–5000 m, and (3) 5500– 5550 m. For the lowest boundary in elevation, the coincidence with the lateral extension of the hydrothermal system inferred from SP measurements suggests that caldera walls act as a barrier for lateral extension of hydrothermal systems. In the summit area, the highest boundary has been related with the summit caldera, inferred by a secondary SP minimum and geological evidence.
    Description: - Institut de Recherche pour le Développement (IRD) - Instituto Geofisico del Peru´ (IGP).
    Description: Published
    Description: 283– 297
    Description: partially_open
    Keywords: caldera ; elliptic Fourier functions ; geomorphology ; self-potential ; Misti volcano ; Peru ; 03. Hydrosphere::03.02. Hydrology::03.02.02. Hydrological processes: interaction, transport, dynamics ; 03. Hydrosphere::03.02. Hydrology::03.02.03. Groundwater processes ; 03. Hydrosphere::03.02. Hydrology::03.02.04. Measurements and monitoring ; 03. Hydrosphere::03.04. Chemical and biological::03.04.05. Gases ; 03. Hydrosphere::03.04. Chemical and biological::03.04.06. Hydrothermal systems ; 04. Solid Earth::04.01. Earth Interior::04.01.02. Geological and geophysical evidences of deep processes ; 04. Solid Earth::04.02. Exploration geophysics::04.02.04. Magnetic and electrical methods ; 04. Solid Earth::04.04. Geology::04.04.03. Geomorphology ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.04. Geology::04.04.11. Instruments and techniques ; 04. Solid Earth::04.08. Volcanology::04.08.05. Volcanic rocks ; 05. General::05.02. Data dissemination::05.02.04. Hydrogeological data ; 05. General::05.05. Mathematical geophysics::05.05.99. General or miscellaneous ; 05. General::05.08. Risk::05.08.99. General or miscellaneous ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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    The role of the Pernicana Fault System in the spreading of Mt. Etna (Italy) during the 2002-2003 eruption (2005)
    Springer
    Details
    Publication Date: 2017-04-04
    Description: Flank instability and collapse are observed at many volcanoes. Among these, Mt. Etna is characterized by the spreading of its eastern and southern flanks. The eastern spreading area is bordered to the north by the EW-trending Pernicana Fault System (PFS). During the 20022003 Etna eruption, ground fracturing along the PFS migrated eastward from the NE Rift, to as far as the 18 km distant coastline. The deformation consisted of dextral en-echelon segments, with sinistral and normal kinematics. Both of these components of displacement were one order of magnitude larger (~1 m) in the western, previously known, portion of the PFS with respect to the newly surveyed (~9 km long) eastern section (~0.1 m). This eastern section is located along a pre-existing, but previously unknown, fault, where displaced man-made structures give overall slip rates (11.9 cm/year), only slightly lower than those calculated for the western portion (1.42.3 cm/year). After an initial rapid motion during the first days of the 20022003 eruption, movement of the western portion of the PFS decreased dramatically, while parts of the eastern portion continued to move. These data suggest a model of spreading of the eastern flank of Etna along the PFS, characterized by eruptions along the NE Rift, instantaneous, short-lived, meter-scale displacements along the western PFS and more long-lived centimeter-scale displacements along the eastern PFS. The surface deformation then migrated southwards, reactivating, one after the other, the NNWSSE-trending Timpe and Trecastagni faults, with displacements of ~0.1 and ~0.04 m, respectively. These structures, along with the PFS, mark the boundaries of two adjacent blocks, moving at different times and rates. The new extent of the PFS and previous activity over its full length indicate that the sliding eastern flank extends well below the Ionian Sea. The clustering of seismic activity above 4 km b.s.l. during the eruption suggests a deep décollement for the moving mass. The collected data thus suggests a significant movement (volume 〉1,100 km3) of the eastern flank of Etna, both on-shore and off-shore.
    Description: Published
    Description: 417-430
    Description: partially_open
    Keywords: Volcano spreading ; Fracturing ; Mt. Etna ; Pernicana Fault System ; NE Rift ; 04. Solid Earth::04.04. Geology::04.04.09. Structural geology ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 05. General::05.02. Data dissemination::05.02.03. Volcanic eruptions ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
    Format: 523 bytes
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  • 100
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    Unusual sedimentary deposits on the SE side of Stromboli volcano, Italy: products of a tsunami caused by the ca. 5000 years BP Sciara del Fuoco collapse? (2005)
    Elsevier
    Details
    Publication Date: 2017-04-04
    Description: The role of sector collapse in the generation of catastrophic volcanigenic tsunami has become well understood only recently, in part because of the problems in the preservation and recognition of tsunami deposits. Tinti et al. [Tinti, S., Bortolucci, E., Romagnoli, C., 2000. Computer simulations of tsunamis due to sector collapse at Stromboli, Italy. J. Volcanol. Geotherm. Res. 96, 103–128] modeled a tsunami produced by the c. 5,000 years BP collapse of the Sciara del Fuoco on the island volcano Stromboli. Although deposits associated with this event are generally lacking on the island, volcaniclastic breccias on the SE side of the island extending to an elevation above 120 m a.s.l. may have been generated by this tsunami. Deposits above 100 m are dominated by coarse breccias comprising disorganized, poorly sorted, nonbedded, angular to subangular lava blocks in a matrix of finer pyroclastic debris. These breccias are interpreted as a water-induced mass flow, possibly a noncohesive debris flow, generated as colluvial material on steep slopes was remobilized by the return flow of the tsunami wave, the run-up of which reached an elevation exceeding 120 m a.s.l. Finer breccias of subrounded to rounded lava blocks cropping out at 15 m a.s.l. are similar to modern high-energy beach deposits and are interpreted as beach material redeposited by the advancing tsunami wave. The location of these deposits matches the predicted location of the maximum tsunami wave amplitude as calculated by modeling studies of Tinti et al. [Tinti, S., Bortolucci, E., Romagnoli, C., 2000. Computer simulations of tsunamis due to sector collapse at Stromboli, Italy. J. Volcanol. Geotherm. Res. 96, 103–128]. Whereas the identification and modeling of paleo-tsunami events is typically based on the observation of the sedimentary deposits of the tsunami run-up, return flow may be equally or more important in controlling patterns of sedimentation.
    Description: Published
    Description: 329-340
    Description: partially_open
    Keywords: tsunami ; flank collapse ; landslide ; run-up ; return flow ; debris flow ; 04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring ; 04. Solid Earth::04.08. Volcanology::04.08.08. Volcanic risk
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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