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  • 1
    ISSN: 0947-3440
    Schlagwort(e): Nucleosides ; HIV ; 3′-Fluoronucleosides ; FLT analogues ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: 2,4(1H,3H)-Quinazolinediones 3a-c, lumazine (3d) and thieno[2,3-d]pyrimidine-2,4(1H,3H)-dione (8) were silylated and condensed with methyl 2,3-dideoxy-3-fluoro-5-O-(4-phenylbenzoyl)-β-D-erythro-pentofuranoside (2) by using trimethylsilyl triflate as a catalyst to afford the corresponding cyclic nucleosides 4 and 9 and acyclic nucleosides 5 and 10. Removal of the protecting group from the glycon moiety was achieved in good yields by treatment with sodium methoxide in methanol at room temperature. The new FLT analogues were devoid of activity against HIV-1 and HSV-1.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 237 (1993), S. 489-497 
    ISSN: 0003-276X
    Schlagwort(e): Immunohistochemistry ; Isolated islets ; Morphometry ; Pancreas ; Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Although there is a recent increase in the use of the isolated pancreatic islets of the rat in the transplantation and functional studies, there has been no detailed quantitative assessment on the size and cellular constituents of islets after the isolation procedure. The present work was undertaken to study the size classes of the isolated islets and the morphometry of their cellular populations.Islets of the rat pancreas were isolated by using the intraductal collagenase digestion technique, the most commonly used procedure for the isolation of pancreatic islets. Different endocrine cells of the isolated islets were stained by immunoperoxidase staining techniques. The distribution of the cellular constituents of the isolated islets was similar to that of the intact islets of the normal pancreas; A, D, and PP cells were peripherally arranged around the centrally located B cells. However, morphometric quantitative study showed that the percent volume and percent number of A, D, and PP cells of the isolated islets were lower than those of the corresponding intact ones. Further, the mean true diameter of the isolated islets was lower than that of the intact ones. These data indicate loss of islet cells during the process of isolation. Most of the lost cells were from the periphery of islets. This may provide an explanation for the incomplete metabolic control and recurrence of hyperglycemia encountered after isolated islet transplantation in the treatment of diabetes mellitus. It seems that further refinements of the isolation techniques are necessary to obtain islet tissue with total cellular integrity, before a complete success in transplantation could be achieved. © 1993 Wiley-Liss, Inc.
    Zusätzliches Material: 13 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 99 (1979), S. 31-35 
    ISSN: 0021-9541
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: WCB6F1 mice of the genotype S1/S1d did not form transient 5-day endogenous spleen colonies following midlethal irradiation, either spontaneously or in response to postirradiation bleeding. Their hematologically normal (+/+) littermates produced colonies equivalent in number and morphologic type to a normal strain (D2B6F1), as evaluated by both macroscopic and microscopic criteria. Bone marrow cells from S1/S1d mice, when transplanted into lethally irradiated +/+ mice, were able to generate equivalent numbers of transient endogenous spleen colonies (TE-CFUs), as compared to that obtained when syngeneic +/+ marrow cells were injected into lethally irradiated +/+ recipients. A defective growth of an early class of hematopoietic progenitor cells, resulting in the clinical course of the S1/S1d anemia is suggested and confirms previous reports on the microenvironmental nature of this abnormality.
    Zusätzliches Material: 3 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Biologie in unserer Zeit 26 (1996), S. 35-42 
    ISSN: 0045-205X
    Schlagwort(e): Life and Medical Sciences
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: Als Grundeinheit aller Organismen ist die einzelne Zelle in der Lage, einen selbständigen Stoffwechsel durchzuführen, nach Teilung zu Zellaggregaten, den Kalli oder Geweben, heranzuwachsen und schließlich zur intakten Pflanze zu regenerieren. In jeder einzelnen dieser regenerierfähigen Pflanzenzellen ist die Information für alle jene Eigenschaften und Fähigkeiten enthalten, die wir in der differenzierten Pflanze wiederfinden. Man spricht von der Totipotenz oder Omnipotenz der Zelle. Präpariert man pflanzliche Zellen aus dem Gesamtverband der komplexen Organismen heraus und kultiviert sie mit Hilfe von Zell- oder Gewebekulturtechniken, so kommt es in der Regel zur Ausbildung relativ homogener, parenchymatischer Zellmassen. Sie besitzen die Fähigkeit, sich unbegrenzt durch Teilung zu vermehren, wodurch sie der Alterung entgegenwirken. Durch Modifikation des Nährmediums mit Phytohormonen lassen sich Differenzierungsprozesse induzieren, die im günstigsten Falle zur Regeneration intakter, fortpflanzungsfähiger Pflanzen führen.
    Zusätzliches Material: 14 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 152 (1992), S. 207-214 
    ISSN: 0021-9541
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: Human preimplantation embryos secrete platelet-activating factor (PAF), which stimulates prostaglandin E2 synthesis from secretory endometrium. This study investigated the action of PAF on phosphatidylinositol 4,5-bisphosphate (Ptdlns(4,5)P2)-specific phospholipase C activity in human endometrium. Slices of normal endometrium were incubated with 5 μCi/ml myo-[2-3H] inositol for 3 h at 37°C in 95% O2 and 5% CO2 to label tissue phosphoinositides. Inositol phosphates were extracted using trichloroacetic acid precipitation and diethylether neutralization and production was measured using Dowex 1-X8 anion-exchange column chromatography. PAF induced rapid and concentration-dependent accumulation of inositol phosphates (IP) from secretory endometrium, but had no effect on endometrium removed in the proliferative phase of the menstrual cycle. The IP3 fraction was significantly elevated from a median value of 14.0 c.p.m. mg-1 dry wt [range: 8-41 c.p.m. mg-1 dry wt] to 28.0 c.p.m. mg-1 dry wt [range: 11-87 c.p.m. mg-1 dry wt, P 〈 0.002] following 1 min exposure of secretory endometrium to PAF-acether, in the presence of 10 mM LiCl. PAF-induced hydrolysis of Ptdlns(4,5)P2 was inhibited by the specific PAF receptor antagonist WEB 2086, in a dose-dependent manner (P 〈 0.02), indicating that in human endometrium Ptdlns(4,5)P2 hydrolysis is mediated via a PAF receptor. These results indicate that PAF receptor coupling activates endometrial Ptdlns(4,5)P2-specific phospholipase C only in the secretory phase of the menstrual cycle, suggesting that the PAF response may be under ovarian steroid regulation. It is proposed that the ability of the endometrium to respond to PAF appears to be a feature of the preparation of this tissue for implantation and that the second messengers generated may play a role in cellular processes involved in the maternal recognition of very early human pregnancy. © 1992 Wiley-Liss, Inc.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Yeast 13 (1997), S. 151-161 
    ISSN: 0749-503X
    Schlagwort(e): histone H1 ; nuclear localization ; green fluorescence protein ; yeast ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The existence of histone H1 in the yeast, Saccharomyces cerevisiae, has long been debated. In this report we describe the presence of histone H1 in yeast. YPL127c, a gene encoding a protein with a high degree of similarity to histone H1 from other species was sequenced as part of the contribution of the Montreal Yeast Genome Sequencing Group to chromosome XVI. To reflect this similarity, the gene designation has been changed to HHO1 (Histone H One). The HHO1 gene is highly expressed as poly A+ RNA in yeast. Although deletion of this gene had no detectable effect on cell growth, viability or mating, it significantly altered the expression of β-galactosidase from a CYC1-lacZ reporter. Fluorescence observed in cells expressing a histone H1-GFP protein fusion indicated that histone H1 is localized to the nucleus.©1997 John Wiley & Sons, Ltd.
    Zusätzliches Material: 5 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 7
    ISSN: 0749-503X
    Schlagwort(e): HIV-1 ; Nef ; Saccharomyces cerevisiae ; yeast expression ; myristylation ; CUP1 ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: The nef gene of human immunodeficiency virus type 1 (HIV-1) has been expressed in the yeast Saccharomyces cerevisiae to produce native Nef proteins. The proteins of Mr 27 kDa and 25 kDa, produced by translation from the first and second start codons of the nef gene react with human HIV-1 antisera. Under low-level steady-state expression conditions, Nef27 undergoes myristylation and is targeted to the nuclear fraction while Nef25 is not myristylated and not nuclear localized. When produced rapidly and to high levels, Nef27 is initially present in the cytoplasm as a soluble myristylated protein that later fractionates with the nucleus.
    Zusätzliches Material: 6 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 8
    ISSN: 0749-503X
    Schlagwort(e): Saccharomyces cerevisiae ; CUP1 ; Cu2+-regulated ; yeast expression ; affinity purification ; glutathione S-transferase ; metallothionein ; Life and Medical Sciences ; Genetics
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie
    Notizen: We describe six new yeast episomal vectors which encode glutathione S-transferase (GST) affinity tags. These allow for the production of GST-fusion proteins in Saccharomyces cerevisiae under the control of the CUP1 promoter. Affinity chromatography with glutathione-Sepharose permits convenient purification of the fusion protein from a yeast lysate. The presence of a protease cleavage site facilitates subsequent removal of the GST tag. The expression and single-step purification of both GST and a functional GST-metallothionein fusion from yeast are shown as an example of the application of these vectors.
    Zusätzliches Material: 3 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 9
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    Bioelectromagnetics 1 (1980), S. 161-170 
    ISSN: 0197-8462
    Schlagwort(e): microwave bioeffects ; nonionizing radiation ; lymphoid cell metabolism ; Life and Medical Sciences ; Occupational Health and Environmental Toxicology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Physik
    Notizen: CBA/J adult male mice were given single or triple exposures to 2450-MHz microwaves in an environmentally controlled wave guide facility. The average absorbed dose rate for a single exposure varied from 12 to 15 mW/g. Shamexposed mice served as controls. Lymphoid cells were collected and tested for metabolic activity on days 3, 6, and 9 following a single exposure, and on days 9, 12, and 16 following triple exposures on days 0, 3, and 6. Cells were cultured in vitro for four hours to seven days before their metabolic rates were assayed. Under these conditions, microwaves failed to produce any detectable change in deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and protein synthesis, as measured by the incorporation of methyl(3H)-thymidine (3H-TDR) (DNA substrate), 3H-uridine (3H-UR) (RNA substrate), and 3H-leucine (protein substrate) by spleen, bone marrow, and peripheral blood lymphocytes (PBL) in vitro. These data suggest that microwave-induced increases in the frequency of complement-receptor (CR)- or surface-immunoglobulin (sIg)-bearing cells were not associated with a concomitant increase in cell proliferation and/or protein synthesis, and favor the concept that microwaves under these conditions stimulate already existing B-cell precursors for maturation.
    Zusätzliches Material: 6 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 10
    Digitale Medien
    Digitale Medien
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1993 (1993), S. 1-5 
    ISSN: 0170-2041
    Schlagwort(e): Carbohydrates ; Nucleosides ; Glycosides ; Uracils ; Arabinose ; Thiouracils ; Chemistry ; Organic Chemistry
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Chemie und Pharmazie
    Notizen: The reaction of silylated 6-substituted uracils 5 with methyl 2,3,5-tri-O-benzoyl-α-D-arabinofuranoside (3) in the presence of trimethylsilyl trifluoromethanesulfonate (TMS triflate) afforded a mixture of the corresponding protected N1,N3-bis(arabinofuranosyl)uracils 6 and the 6-substituted 2,3,5-tri-O-benzoyl-α-D-arabinofuranosyluracils 8. Deprotection of 6 and 8 gave the corresponding α nucleosides 7 and 9. The reaction of silylated 6-ethyl- and 6-methylthiouracil with 3 afforded a mixture of S- and N3-glycosides 10 and 11. The glycosides 10 were deblocked by treatment with methanolic ammonia to obtain the deprotected α nucleosides 12.
    Materialart: Digitale Medien
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