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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 83 (1974), S. 211-218 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Viral infection by vesicular stomatitis virus (VSV) as well as cellular protection against it were studied in cultured human diploid fibroblast cells (WI38 strain) of varying senescence (passage) level. Full protection against viral infection can be achieved by pretreatment of cells with an interferon inducer (complex of polycytidylate and polyinosinate) or by pretreatment with concentrates of interferon itself. The late passages (over 45) require higher concentration of both agents than the medium passages (25-45); a complete failure of protective mechanisms occurs only close to cellular death. Furthermore, effects of confluency and of duration of induction impulse were studied. WI38 cells are sensitive to VSV infection through their entire life span; however, during the last passage before their death by senescence, VSV replication is significantly decreased. It is concluded that even in relatively senescent cells (a) protection mechanisms which were not used previously can be activated, (b) synthesizing machinery necessary for efficient support of viral replication is sustained, and (c) release of lysosomal enzymes ending the viral replication does not begin sooner than with cells of earlier passage level.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 19 (1988), S. 401-409 
    ISSN: 0148-7280
    Keywords: cyclodextrin ; reproduction ; gerontology ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Both ejaculated semen and epididymal contents from an individual male contain sperm that differ in various physicochemical characteristics. An experiment is reported in which epididymides from rats 5-24 months old were subjected to density gradient centrifugation to separate gametes of different stages of maturity. The research was designed to examine typical changes in “profiles” of sperm maturity during the reproductive lifetime of rats. Also, testosterone complexed with cyclodextrin that mimics the episodic release of the endogenous hormone was used to supplement the decreased circulating titers of some of the old males. Results revealed clear ontogenetic patterns of gradually decreasing reproductive competence as measured by absolute numbers of sperm, circulating levels of testosterone, and various other physiological markers of fertility. Sperm profiles also revealed age-specific changes with a shift toward progressively more mature, perhaps senile, gametes that begins at middle age. Testosterone supplementation (400 μg/kg b.w./day for 30 days) failed to restore sperm numbers or other measures of physiology in the old males, but the steroid modified sperm profiles to approximate more closely the profiles characteristic of young adult males than either untreated middle-aged or old males. The data were interpreted as suggesting that epididymal sperm profiles clearly identify males of different ages, and that the aging epididymis retains its capacity to respond to manipulations that modify the endocrine milieu.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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