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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 459 (1985), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Radiation and environmental biophysics 20 (1982), S. 195-200 
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Summary To investigate whether residual radiation damage in hematopoietic tissue is measurable in situ by a change in cell turnover, the retention of the thymidine analogue 5-(125-I)iodo-2′-deoxyuridine (125-IUdR) following incorporation into DNA of cells in bone marrow and spleen of mice was measured 35 days after 0–500 rad whole body gamma irradiation. In the bone marrow a rapid and a slow turnover component of 125-IUdR retention were found. Both components were almost identical for unirradiated and irradiated mice. In the spleen the 125-IUdR retention curves exhibited three components with increasingly prolonged half-times. In the second component the half-time was longer in irradiated than in unirradiated mice. This was dose-dependent. The increased half-time of 125-IUdR retention in irradiated spleens may be caused by direct cellular damage of long-lived cells (lymphocytes, early hematopoietic progenitor cells) or/and by diminished stimulation of proliferation by microenvironmental or long-range factors.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Radiation and environmental biophysics 24 (1985), S. 119-123 
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Summary In rodents, residual damage is inducible in hematopoietic stem cells by exposure to ionizing radiation or alkylating agents. This damage can be assayed in mice by transferring bone marrow into lethally irradiated syngeneic recipients and subsequently measuring the incremental increase of 5-(125I)iodo-2′-deoxyuridine incorporation in spleens. In this study, bone marrow from mice treated 3 weeks previously with Methylnitrosourea (50 mg/kg) or 450 rad was injected into recipients in order to determine possible residual effects of treatment on erythroid cell differentiation following stem cell seeding. Such effects were detected by a reduced amount of59Fe incorporation into spleens, thus indicating transfer of residual stem cell damage to differentiating cells.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-0738
    Keywords: Valepotriates ; Epichlorohydrin ; Scopolamine ; Granulocyte/Macrophage ; Erythrocyte ; T-Lymphocyte colony assays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Zusammenfassung Die epoxidhaltigen Valepotriate Valtrat/Isovaltrat und Dihydrovaltrat, die aus den Wurzeln von Valerianaceae isoliert und als sedative Arzneimittel benutzt werden, wurden hinsichtlich ihrer Wirkung auf untransformierte hämatopoietische Zellen untersucht, nachdem ein Alkylierungspotential und Zytotoxizität auf Tumorzellen gefunden worden waren. Die Stoffe wurden in empfindlichen in vitro-Tests bezüglich ihrer Wirkung auf Vorläuferzellen für Granulo/yten/Makrophagen (GM-CFC) und Erythrozyten (E-CFC) aus dem Knochenmark von Mäusen sowie auf Kolonie-bildende PHA-stimulierte T-Lymphozyten des menschlichen peripheren Blutes geprüft. Bei Valtrat-Zugabe betrug die ID50 für GM-CFC und T-Lymphozyten ca. 3×10−6 M, bei Dihydrovaltrat ca. 2×10−5 M. Für E-CFC-Kolonien ergab sich bei beiden Substanzen eine ID50 von ca. 3×10−8 M. Die Wirkung von Valtrat zeigte sich bei niedrigerer Konzentration als die Wirkung des bekannten Alkylans Epichlorhydrin. Das zum Vergleich untersuchte nichtalkylierende Epoxid l-Scopolamin war eindeutig am wenigsten wirksam. Die Valtrat- und Dihydrovaltrat-Effekte waren nicht reversibel durch Auswaschen der Kulturen. Es kann geschlossen werden, daß die untersuchten Valepotriate wahrscheinlich stark zytotoxisch sind für die in den Tests verwendeten untransformierten hämatopoietischen Zellen.
    Notes: Abstract The epoxide-bearing valepotriates valtrate/isovaltrate and dihydrovaltrate, isolated from Valerianaceae roots and used as common sedative drugs, were investigated for their effects on untransformed hematopoietic cells after an alkylating potential and cytotoxicity to tumor cells had been found. The compounds were added to sensitive in vitro assays using granulocyte/macrophage (GM-CFC) and erythrocyte (E-CFC) colony forming cells from murine bone marrow early progenitor cells as well as colony forming PHA-stimulated T-lymphocytes from human peripheral blood. The ID50 for both GM-CFC and T-lymphocytes incubated with valtrate was found to be about 3×10−6 M, with dihydrovaltrate about 2×10−6 M. On erythrocyte colonies (E-CFC) both compounds showed an ID50 of about 3×10−8 M. Valtrate effects were exhibited at lower concentrations than effects caused by the known alkylating agent epichlorohydrin. The non-alkylating epoxide l-scopolamine taken for reference was clearly the least effective. Valtrate and dihydrovaltrate effects on GM-CFC were not reversible by washing the cultures. It is concluded that the valepotriates investigated are likely to be strongly cytotoxic to the untransformed hematopoietic cells studied.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 1432-2099
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Physics
    Notes: Summary The rate of cell entry from the compartment of hematopoietic early progenitor cells into differentiation was determined in sublethally irradiated mice. By use of the criterion of repopulating ability, transplantation of 5-(125I) iodo-2′-deoxyuridine labeled bone marrow cells into fatally irradiated syngeneic recipients allows to measure the relative number of early progenitor cells lodging in the spleen and the turnover of these cells in the donors. Following 450 rad the relative number of transplantable early progenitor cells in S-phase recovers to normal within 2 weeks and stabilizes after 5 weeks. At this time, the labeled progenitors turn over with a half-time of 1.4–2.2 days; the respective times for unirradiated mice are 1.5–1.8 days. Thus, quantitative and qualitative residual radiation damage that is known to exist in the compartment of CFU-S, is disguised within 2–5 weeks after irradiation by proliferative compensation in the entirety of early hemopoietic precursor cells which are here defined by their capacity of selfrenewal and delivery of differentiated cells and of seeding to spleens of lethally irradiated recipients.
    Type of Medium: Electronic Resource
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