ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Life and Medical Sciences  (766)
  • 1995-1999  (228)
  • 1985-1989  (518)
  • 1935-1939  (20)
Collection
Publisher
Years
Year
  • 1
    ISSN: 0192-253X
    Keywords: tubulin genes ; microtubules ; Arabidopsis thaliana ; Life and Medical Sciences ; Genetics
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Microtubules are important components of the cytoskeleton of plant cells and play key roles in plant growth and morphogenesis. Recent molecular studies have begun to elucidate the structure and expression of plant genes coding for the major components of microtubules, α- and β-tubulin. Tubulin amino acid sequences deduced from the DNA sequences of eight higher plant tubulin genes are 79-87% homologous with constitutively expressed mammalian tubulins. The genome of the model plant system Arabidopsis thaliana contains four dispersed α-tubulin sequences and at least seven β-tubulin sequences, only two of which appear to be linked. Of the five A. thaliana genes whose expression has been analyzed, the transcripts of one α-tubulin and one β-tubulin gene are constitutively expressed in roots, leaves, and flowers. A second α-tubulin gene is expressed predominately in flowers; the transcripts of the second and third β-tubulin genes are found predominately in leaves or in roots, respectively.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 16 (1995), S. 70-74 
    ISSN: 0197-8462
    Keywords: video display terminals ; embryogenesis ; teratology ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Physics
    Notes: Eighty-nine Swiss Webster mice were randomly divided into four groups: a control group, a pulsed magnetic field (PMF) group, a cytosine arabinoside (ara-C, a teratogen) group, and, a combined PMF + ara-C group. Mice in the PMF and PMF + ara-C groups were irradiated with a PMF (a sawtooth waveform with 52 μs rise time, 12 μs decay time, and 15.6 kHz frequency) at a peak magnetic flux density of 40 μT for 4 hours daily on days 6-17 of gestation. The mice in the ara-C and the PMF + ara-C groups were injected intraperitoneally on day 9 of gestation with 10 mg/kg of ara-C. The incidence of resorption and dead fetuses was not affected by PMF but was increased by ara-C injection. The malformation incidence of cleft palate (CP) and/or cleft lip (CL) was significantly higher in all three of the treated groups than in the control group (P 〈 0.05). If, however, statistical analyses had been done on litters rather than on individual fetuses, they would show that the incidence of CP and/or CL in the PMF group is not significantly greater than that in the control group. A significantly higher incidence of CP and/or CL was found in the PMF + ara-C group (49%) than the ara-C alone group (26.1%). These data suggest that PMF might enhance the development of ara-C-induced CP and/or CL. The incidence of minor variations in skeletal development, including reduction of skeletal calcification and loss of skeleton, was not statistically significant in the PMF group. However, it was higher in the two ara-C-treated groups, and there was no significant difference between the ara-C alone group and the ara-C + PMF group. From these results it is concluded that the very weak embryotoxic effects of PMF exposure may be revealed and enhanced in combination with a teratogenic agent. © 1995 Wiley-Liss, Inc.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 3
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Molecular Reproduction and Development 41 (1995), S. 435-448 
    ISSN: 1040-452X
    Keywords: Peri-implantation embryogenesis ; Trophoblast cells ; Recombinant proteins ; Integrins ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: To investigate the mechanism of trophoblast adhesion to fibronectin, we cultured blastocysts in serum-free medium on proteolytic fibronectin fragments containing its major functional domains, and localized fibronectin-binding integrins in outgrowing trophoblast cells by immunofluorescent staining. Outgrowth comparable to that obtained with intact fibronectin was observed using a 120 kD chymotryptic fragment containing the central cell-binding domain (FN-120) and the Arg-Gly-Asp (RGD) recognition sequence. A 40 kD COOH-terminal chymotryptic fragment of fibronectin containing both a heparin-binding region and an alternate (non-RGD) cell-binding site was inactive in supporting trophoblast adhesion. Three synthetic peptides derived from the heparin-binding domain, including the CS1 alternate cell-binding site, were also unable to promote trophoblast cell adhesion. A 75 kD recombinant protein, ProNectin F, containing 13 copies of the cell recognition epitope of fibronectin, Val-Thr-Gly-Arg-Gly-Asp-Ser-Pro-Ala-Ser, vigorously supported blastocyst outgrowth. Blastocyst outgrowth was not significantly different when surfaces were precoated with cellular fibronectin, which contains an alternatively spliced type III repeat and is the form actually encountered in vivo. Several putative fibronectin receptors were localized in trophoblast outgrowths by immunofluorescent labeling. Antibodies reactive with integrin subunits α3, α5, αllb, αv, β1 and β3, but not α4, all bound to trophoblast cells. Antibodies raised against either the β1 or β3 integrin subunits significantly inhibited fibronectin-mediated outgrowth. These findings demonstrate the key role of the central cell-binding domain of fibronectin in trophoblast adhesion, and suggest four RGD-binding integrins, α3β1, α5β1, αllbβ3, and αvβ3, that could mediate trophoblast adhesion in vitro and may play an important role during implantation. © 1995 Wiley-Liss, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 4
    ISSN: 1040-452X
    Keywords: EGF-like ligands ; Postnatal development ; RT-PCR ; Immunocytochemistry ; Immunoblotting ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Amphiregulin (Ar) and Cripto-1 (Cr-1) are growth promoting peptides that share amino acid sequence homology with epidermal growth factor (EGF). The present study examined Ar and Cr-1 mRNA and protein expression during various stages of C57BL/6 mouse mammary morphogenesis. Reverse transciption-polymerase chain reaction (RT-PCR) was used to detect transcripts for Ar and Cr-1 at all stages of mammary development. Immunocytochemical (ICC) localization demonstrated that in virgin 4-week to mature 12-week-old mouse fourth inguinal mammary gland, Ar and Cr-1 are expressed in the stromal cells, luminal epithelial cells, and myoepithelial cells of the branching ducts. Ar, and to lesser extent Cr-1, were also found in the epithelial cap cells and in the luminal epithelial cells of the advancing terminal end bud (TEB) from virgin 4-week and 6-week-old mice. Western blot analysis demonstrated that both Ar (28 and 26 kDa) and Cr-1 (90, 67, 56, and 21 kDa) proteins are expressed in virgin, 13.5 day midpregnant and in the 14 day lactating mammary gland. In addition, Ar and Cr-1 are associated with developing alveolar structures as determined by ICC. These results imply that together with EGF and transforming growth factor alpha (TGFα), Ar and Cr-1 may play salient roles as modifiers in the morphogenesis and differentiation of the mammary gland. © 1995 Wiley-Liss, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 5
    ISSN: 0730-2312
    Keywords: elastase inhibitors ; β-lactams ; lung damage ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Human polymorphonuclear leukocyte elastase (PMN elastase) is inhibited by L-659, 286 (7α-methoxy-8-oxo-3-[[(1,2,5,6-tetrahydro-2-methyl-5,6-dioxo-1,2,4-triaz-in-3-yl)thio]methyl]-5-thia-1-aza-6R-bicyclo [4.2.O]oct-2-ene-2-pyrrolidine carboxamide-5,-dioxide) with a Ki of 0.4 μM. This inhibition is time-dependent, rapid, and only slowly reversible, with a t1/2 of 〉 3 days at 25°C. L-659, 286 is also highly selective for PMN elastase, as it does not inhibit thrombin, trypsin, papain, plasmin, chymotrypsin, or cathepsin G. L-659, 286 administered intratracheally inhibits lung damage caused by administration via the same route of human PMN elastase into hamsters. In marmosets, L-659, 286 is cleared from blood very rapidly after an intravenous injection but is recovered in bronchoalveolar lavage fluid for several hours after intratracheal administration.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 140 (1989), S. 549-557 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Entry times for spherical (no pseudopods) polymorphonuclear leukocytes (PMNs) into a 4 μm micropipet have been measured as a function of pipet suction pressure (2,500-20,000 dyn/cm2) and concentration of the drug pentoxifylline (PTX, 0.1-10.0 mM). For control cells (0 mM PTX), entry rates (reciprocal entry times) increased almost linearly with increasing suction pressure, indicating a Newtonian-like behavior. With incubation in PTX solutions, entry rate vs. suction pressure became increasingly non-linear, suggesting a shear-thinning effect for the dissipative structure. At a given suction pressure the rate of entry showed a dose-dependent increase with increasing PTX concentration, the effect being most pronounced at high suction pressures (20,000 dyn/cm2). Also, with increasing PTX concentration two other effects were observed: (i) there was a decreased incidence of cells that displayed pseudopodia, and (ii) there was an increased incidence of cells forming hernias and an increased streaming of cell cytoplasm during aspiration. The first observation points to a down-regulation of the cell's functional ability to “activate” in response to surface/chemical stimuli, and the second indicates that both the cortical and cytoskeletal networks are weakened either by disruption and/or reduction in density of the protein polymers. These observations are in line with other recently published experiments which suggest that the rheological effects of pentoxifylline on PMNs may be associated with the state of actin.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 7
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The growth factors PDGF-AA and PDGF-BB have previously been shown to be potent mitogens for human periodontal ligament (hPDL) cells in vitro. Additionally, the mitogenic response to PDGF-AA has been shown to be specifically inhibited by TGF-β. The purpose of the present investigation was to examine the binding of PDGF-AA and PDGF-BB, and the modulation of PDGF binding by TGF-β, in hPDL cells. Scatchard analysis identified an average of 32,000 PDGF-AA high-affinity binding sites per cell with a dissociation constant (Kd) of 0.66 nM and an average of 36,000 PDGF-BB binding sites per cell with a dissociation constant (kd) of 0.44 nM. After treatment with TGF-β, the receptor number for PDGF-AA was found to specifically decrease by approximately 50%, with no change in binding affinity. This reduced number of binding sites was shown to correlate with both a decrease in levels of receptor tyrosine phosphorylation and a decreased number of α receptor subunits. Northern blot analysis identified the TGF-β-mediated decrease in PDGF α receptor subunit mRNA levels. PDGF-BB showed little change in the number of binding sites or in the binding affinity with TGF-β treatment, and the data were consistent with an increase in the number of β receptor subunits. These results demonstrate nearly equivalent numbers of receptors for both PDGF-AA and PDGF-BB in hPDL cells. Also, modulation of PDGF binding, by TFG-β, was shown to result in a reduced number of α receptor subunits with an increase in the number of β receptor subunits. © 1995 Wiley-Liss, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 8
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Prior studies have shown that vitamin D regulation of protein kinase C activity (PKC) in the cell layer of chondrocyte cultures is cell maturation-dependent. In the present study, we examined the membrane distribution of PKC and whether 1α,25-(OH)2D3 and 24R,25-(OH)2D3 can directly regulate enzyme activity in isolated plasma membranes and extracellular matrix vesicles. Matrix vesicle PKC was activated by bryostatin-1 and inhibited by a PKC-specific pseudosubstrate inhibitor peptide. Depletion of membrane PKC activity using isoform-specific anti-PKC antibodies suggested that PKCα is the major isoform in cell layer lysates as well as in plasma membranes isolated from both cell types; PKCζ is the predominant form in matrix vesicles. This was confirmed in Western blots of immunoprecipitates as well as in studies using control peptides to block binding of the isoform specific antibody to the enzyme and using a PKCζ-specific pseudosubstrate inhibitor peptide. The presence of PKCζ in matrix vesicles was further verified by immunoelectron microscopy. Enzyme activity in the matrix vesicle was insensitive to exogenous lipid, whereas that in the plasma membrane required lipid for full activity. 1,25-(OH)2D3 and 24,25-(OH)2D3 inhibited matrix vesicle PKC, but stimulated plasma membrane PKC when added directly to the isolated membrane fractions. PKC activity in the matrix vesicle was calcium-independent, whereas that in the plasma membrane required calcium. Moreover, the vitamin D-sensitive PKC in matrix vesicles was not dependent on calcium, whereas the vitamin D-sensitive enzyme in plasma membranes was calcium-dependent. It is concluded that PKC isoforms are differentially distributed between matrix vesicles and plasma membranes and that enzyme activity is regulated in a membrane-specific manner. This suggests the existence of a nongenomic mechanism whereby the effects of 1,25-(OH)2D3 and 24,25-(OH)2D3 may be mediated via PKC. Further, PKCζ may be important in nongenomic, autocrine signal transduction at sites distal from the cell. © 1996 Wiley-Liss, Inc.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 11 (1985), S. 349-365 
    ISSN: 0148-7280
    Keywords: spermatozoa ; mammalian ; fertilization ; mammalian ; nucleus ; spermatozoon ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Additional Material: 22 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
  • 10
    ISSN: 0148-7280
    Keywords: bull ; semen ; fluorophore ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A dual fluorescent staining system utilizing 5 (and-6)-carboxy-4′,5′-dimethyl fluorescein diacetate (CDMFDA) and Hydroethidine (HED) was developed to provide quantifiable information reflective of spermatozoal viability and fertilizing potential. Cryopreserved spermatozoa from ten bulls on which there was fertilizing capacity information were incubated for 1.5, and 3 hr at 39°C prior to fluorogenic staining. Spermatozoa were analyzed using both a FACS Analyzer and an EPICS V flow cytometer to determine if a particular fluorescence pattern was due to an instrumental artifact or cellular processes. Five fluorescent cellular populations were identified by the FACS Analyzer and three populations by the EPICS V. Spermatozoa were quantified after each incubation time for red (HED) and green (CDMFDA) fluorescence. Viable spermatozoa retained the greatest amount of both green and red fluorescence. Dead or moribund spermatozoa had a decrease in over-all fluorescence. The number of viable cells at 0 hr plus the number of dead or morbid cells at any time period were identified by the FACS Analyzer as important in estimating the potential fertility of a bull. The EPICS V identified the number of dead or moribund cells as being related to nonreturn rates. Incubation of samples decreased cellular viability, which resulted in reduced levels of both green and red fluorescence. Similarities between data obtained with both flow cytometers illustrated that cellular processes, not instrumental artifacts, were responsible for the decrease in over-all fluorescence when viability declined, the relationship between the number of cells with specific fluorescence levels and nonreturn rates, and the incubative-induced changes in fluorescence patterns.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...