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1

Electronic Resource

Electro-optic and photorefractive two-beam coupling properties of lead barium niobate crystals (1998)

Liu, Alice ; Hesselink, Lambertus

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 83 (1998), S. 2826-2830

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ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: Lead barium niobate crystals (Pb1−xBaxNb2O6) are attractive photorefractive materials for holographic data storage. The electro-optic coefficients r33 and r13 are determined using a Mach–Zehnder interferometer setup, and are measured to be 160±20 and 32±4 pm/V, respectively. The angular dependence of the photorefractive two-beam coupling gain is also investigated, and the products of the electro-optic coefficients and the electron-hole competition factor rζ are determined and compared with the electro-optic coefficients obtained using the interferometric method. It is found that the electron-hole competition factor is at least 0.7, indicating that the photorefractive process is mostly due to electrons. The effective trap densities at several wavelengths are also determined from the gain dispersion measurements, and are found to be 1.3–2.2×1016 cm−3. © 1998 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.367043

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2

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Tributyltin is a potent inducer of the heat shock response in human diploid fibroblasts (1992)

Zhang, Hua ; Liu, Alice Y.-C.

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 153 (1992), S. 460-466

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: Submicromolar concentrations of tributyltin (TBT), a commercially used organotin compound, were found to induce the expression of several stress proteins, most notably HSP89 and HSP70, in IMR-90 human diploid fibroblats in a time- and dose-dependent manner. This induction can be demonstrated by quantitation of 1) synthesis of the heat shock proteins (HSPs), 2) relative abundance of mRNA of hsp70, and 3) transient expression of a human hsp70 promoter driven reporter gene. TBT also increased the abundance of mRNA of heme oxygenase, whereas heat shock was without effect. Analysis of protein binding to a consensus heat shock element (HSE)by electrophoretic mobility shift assay suggests that the induction of the heat shock response by TBT was attributable to activation of the heat shock transcription factor (HSTF). © 1992 Wiley-Liss, Inc.

Additional Material: 6 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041530304

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3

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Differential effects of the tumor promoter phorbol-12-myristate-13-acetate on the morphological and biochemical differentiation of N-18 mouse neuroblastoma cells (1985)

Liu, Alice Y.-C. ; Chen, Kuang Yu

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 125 (1985), S. 387-392

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: The phorbol ester tumor promoter phorbol-12-myristate-13-acetate (PMA) was found to have differential inhibitory effects on the expression of morphological and biochemical differentiation of N-18 mouse neuroblastoma cells. PMA completely inhibited neurite extension and associated growth characteristics and partially inhibited the increased expression of R1 cAMP-binding protein; PMA had no effect on the induction of acetylcholinesterase activity in cells prompted to differentiate either by treatment with 1 mM dibutyryl cAMP or by serum deprivation. 4-α-Phorbol-12, 13-didecanoate, an inactive analogue of phorbol ester tumor promoter, was without effect. The implications of these findings concerning the mechanism of action of phorbol ester tumor promoters in the control of cell differentiation are discussed.

Additional Material: 4 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041250305

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4

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Increased level of cAMP-dependent protein kinase in aging human lung fibroblasts (1986)

Liu, Alice Y.-C. ; Chang, Zee-Fen ; Chen, Kuang Yu

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 128 (1986), S. 149-154

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: Regulation of the expression of cAMP-dependent protein kinase in cellular aging was studied using the IMR-90 diploid human lung fibroblasts. The level of cAMP-dependent protein kinase present in cell extracts was monitored by (1) photoactivated incorporation of 8-N3-[32P]cAMP into the 47,000- and 54,000-dalton regulatory subunits of the type I and type II cAMP-dependent protein kinases, respectively; (2) cAMP-dependent phosphorylation of histone II AS catalyzed by the catalytic subunit of the kinase; and (3) fractionation and analysis of the type I and type II cAMP-dependent protein kinase by DEAE-Sephacel column chromotography. Our results showed an approximately two- to threefold increase in the level of the type I cAMP-dependent protein kinase and a somewhat smaller increase in the type II kinase in extracts of the “old” IMR-90 cells (population doubling 〉48) as compared to that of the “young” cells (PDL 22-27). The timing of the increase in cAMP-dependent protein kinase coincided with a significant decrease in the proliferative potential of the cells. This result together with previously demonstrated effects of cAMP in the control of cell growth and differentiation and the increased expression of cAMP-dependent protein kinase during terminal differentiation of the murine preadipocytes (3T3-L1) and myoblast (L-5, L-6, and C2C13) suggests that regulation of the levels of cAMP and cAMP-dependent protein kinase plays a significant role in the control of cell growth and differentiation.

Additional Material: 5 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041280203

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5

Electronic Resource

Molecular events involved in transcriptional activation of heat shock genes become progressively refractory to heat stimulation during aging of human diploid fibroblasts (1991)

Liu, Alice Y.-C. ; Choi, Hueng-Sik ; Lee, Yoon-Kwang ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 149 (1991), S. 560-566

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: We examined the induction, by heat shock, of heat shock transcription factor (HSTF) DNA-binding and hsp 70 gene promoter activities during aging of the IMR-90 human diploid fibroblasts. Cells with population doubling level (PDL) ranging from 15-48 were heat shocked at temperatures of 39, 42, and 45°C for various time periods; the binding of HSTF to its consensus DNA was determined by gel retardation assay and the promoter activity of the human hsp 70 gene was analyzed by transient expression of reporter gene activity. We observed that the induction of HSE-binding activity was inversely related to the PDL of the cells used. Importantly, as cells progress through their life span, a higher temperature and a longer period of heat shock were needed to evoke an optimal increase in HSE-binding activity. A substantial and rapid (within 30 min) increase in HSE-binding activity was observed when PDL 20 cells were heat shocked at 39, 42, or 45°C. However, PDL 35 cells did not respond to 39°C, and PDL 48 cells responded slowly to heat shock at 45°C, but not 39 or 42°C. Experiments on the heat induced increase in hsp 70 promoter driven reporter gene expression provided similar information on the age-dependent decrease in transcriptional activation of hsps. These results were further corroborated by quantitation of the abundance of mRNA of hsp 70. Analysis of the cAMP induced expression of the rat somatostatin promoter driven CAT gene provided evidence that the decrease in transcriptional activation of hsps in aging diploid cells was not a reflection of a generalized dysfunction of signal transduction. We conclude that functional changes in the heat shock response occur before cells lose their capacity to replicate, and we suggest that these changes are likely to have a central role in the expression of the aging phenotype.

Additional Material: 6 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041490327

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6

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Changes of ornithine decarboxylase activity and polyamine content upon differentiation of mouse NB-15 neuroblastoma cells (1982)

Chen, Kuang Yu ; Presepe, Vincent ; Parken, Nancy ; [et al.]

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 110 (1982), S. 285-290

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: The possible functions of ornithine decarboxylase (ODC) and polyamines in the differetiation of mouse NB-15 neuroblastoma cells were investigated by examining the changes of these parameters in the differentiaton and nondifferentiating NB-15 cells over a 5-day culture period. Differentiation of NB-15 cells was induced by the addition of dibutyryl cyclic AMP and 3-isobutyl-1-methylxanthin (IBMX) to the growth medium and was monitored by neurite outgrowth, increase of acetylcholinesterase (AChE), and RI cAMP-binding protein. Plating of NB-15 cells in fresh serum-containing growth medium was accompanied by rapid growth and a marked increase of ODC activity, this early increase of ODC activity was attenuated, both in duration and in magnitude, in the differentiating cells. The spermidine content of the differentiating neuroblastoma cell was significantly lower than that of the nondifferentiating cells. In the fully differentiated neuroblastoma cells, the ODC activity and spermidine content were lower than that of the undifferentiated cells by approximately 15-fold and five-fold, respectively. Based on these results it is proposed that changes of polyamine metabolism may be of significance in the differentiation of mouse neuroblastoma cells.

Additional Material: 4 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041100311

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7

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Changes of serum-induced ornithine decarboxylase activity and putrescine content during aging of IMR-90 human diploid fibroblasts (1986)

Chenc, Kuang Yu ; Chang, Zee-Fen ; Liu, Alice Y.-C.

New York, NY [u.a.] : Wiley-Blackwell

Journal of Cellular Physiology 129 (1986), S. 142-146

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ISSN: 0021-9541

Keywords: Life and Medical Sciences ; Cell & Developmental Biology

Source: Wiley InterScience Backfile Collection 1832-2000

Topics: Biology , Medicine

Notes: The roles of ornithine decarboxylase (ODC, EC 4.1.1.17) and polyamines in cellular aging were investigated by examining serum-induced changes of these parameters in quiescent IMR-90 human diploid fibroblasts as a function of their population doubling level (PDL) and in human progeria fibroblasts. Serum stimulation caused increases of ODC and DNA synthesis in IMR-90 human diploid fibroblasts, with maximal values occurring, respectively, 10 hr and 22 hr after serum stimulation. Both serum-induced ODC activity and DNA synthesis in IMR-90 cells were found to be inversely related to their PDL. Maximal ODC activity and DNa synthesis in young cells (PDL = ∼ 18-22) were, respectively, five-fold and six-fold greater than that in old cells (PDL = ∼ 50-55), which in turn were comparable or slightly higher than that in progeria fibroblasts. Polyamine contents (putrescine, spermidine, and spermine) in quiescent IMR-90 cells did not show significant PDL-dependency. The putrescine and spermine contents in quiescent progeria cells were comparable to those in quiescent IMR-90 cells. The spermidine content in quiescent progeria cells, however, was extremely low, less than half of that in quiescent IMR-90 cells. Serum stimulation caused a marked increase in putrescine content in young cells but not in old cells or in progeria cells. The spermidine and the spermine content in IMR-90 cells, either young or old, and in progeria cells did not change significantly after serum stimulation. Our study indicated that aging of IMR-90 human diploid fibroblasts was accompanied by specific changes of polyamine metabolism, namely, the serum-induced ODC activity and putrescine accumulation. These changes were also observed in progeria fibroblasts derived from patients with Hutchinson-Cilford syndrome.

Additional Material: 3 Ill.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1002/jcp.1041290203

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Specific targeting of ovarian tumor-associated macrophages by large, anionic nanoparticles (2020)

Haber, Tom ; Cornejo, Yvonne R. ; Aramburo, Soraya ; [et al.]

National Academy of Sciences

In: PNAS - Proceedings of the National Academy of Sciences of the United States of America. 2020; 117(33): 19737-19745. Published 2020 Jul 30. doi: 10.1073/pnas.1917424117.

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Publication Date: 2020-07-30

Description: Immunotherapy is emerging as one of the most effective methods for treating many cancers. However, immunotherapy can still introduce significant off-target toxicity, and methods are sought to enable targeted immunotherapy at tumor sites. Here, we show that relatively large (〉100-nm) anionic nanoparticles administered intraperitoneally (i.p.) selectively accumulate in tumor-associated macrophages (TAMs). In a mouse model of metastatic ovarian cancer, fluorescently labeled silica, poly(lactic-co-glycolic acid), and polystyrene nanoparticles administered i.p. were all found to selectively accumulate in TAMs. Quantifying silica particle uptake indicated that 〉80% of the injected dose was in TAMs. Particles that were smaller than 100 nm or cationic or administered intravenously (i.v.) showed no TAM targeting. Moreover, this phenomenon is likely to occur in humans because when freshly excised human surgical samples were treated with the fluorescent silica nanoparticles no interaction with healthy tissue was seen but selective uptake by TAMs was seen in 13 different patient samples. Ovarian cancer is a deadly disease that afflicts ∼22,000 women per year in the United States, and the presence of immunosuppressive TAMs at tumors is correlated with decreased survival. The ability to selectively target TAMs opens the door to targeted immunotherapy for ovarian cancer.

Print ISSN: 0027-8424

Electronic ISSN: 1091-6490

Topics: Biology , Medicine , Natural Sciences in General