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  • 1
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract A report linking human polycystic ovary with increased exposure to environmental DDT (Heinrichset al. 1971) prompted the present study comparing effects of PCB and DDT or their combination on reproduction in female rats under more realistic conditions with respect to level (75 and 150 ppm), route of administration (dietary contaminant), and period of exposure (8 and 36 weeks). Evaluation of estrous cycle length, mating frequency, number and size of litters; as well as plasma levels of DDT, PCB, progesterone (P), and 17α=hydroxyprogesterone (17α=OH-P), permitted comparison of short and long term reproductive changes from ingestion of two levels of DDT and/or PCB. PCB reduced plasma progesterone (p〈.01) while plasma 17α OH-P was unchanged by PCB or DDT. High DDT and PCB abolished reproduction. Histologically, distinct ovarian stromal changes accompanied 150 ppm of PCB, while increased numbers of more prominent follicular cysts were evident with 150 ppm of DDT. Although DDT and PCB generally reduced or abolished litter production, no treatment tested significantly altered litter size. Long term chronic ingestion of more realistic levels of technical DDT (85%p,p′, 15%o,p′-DDT) in these studies did not lead to polycystic ovaries in adult rats comparable to those reported following i.v. administration of pureo,p′-DDT to immature rats. Plasma DDT levels above 800 ppb are clearly detrimental to reproduction, while levels below 500 ppb had little effect. Finally, we present the first evidence reported to our knowledge demonstrating that prolonged ingestion of PCB (150 ppm) markedly reduces reproduction (p〈.05) accompanied by significantly reduced progesterone in plasma (p〈.01) as well as by histologically characteristic ovarian stromal changes not seen with DDT alone.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Archives of environmental contamination and toxicology 10 (1981), S. 171-183 
    ISSN: 1432-0703
    Source: Springer Online Journal Archives 1860-2000
    Topics: Energy, Environment Protection, Nuclear Power Engineering , Medicine
    Notes: Abstract Livers from mature female rats exposed for up to 36 weeks to dietary levels of Aroclor® 1242 (75 or 150 ppm) and/or commercial grade DDT (75 or 150 ppm) were compared to those from animals receiving basal diets. In earlier studies, reproductive effects of the test substances were assessed. Moreover, the markedly abnormal gross appearance of the livers led to examination of the hepatic effects of PCB and DDT in more detail, at both the light microscope (LM) and electron microscope (EM) levels. Light microscopy revealed focal liver cell necrosis in rats fed PCB, DDT, and PCB-DDT combinations. Higher levels of PCB (150 ppm) increased the severity of necrosis. Feeding both DDT and PCB produced similar effects at 75 ppm, and caused atypical centrolobular regeneration, occasionally forming nodules resembling small tumors. The experimentally induced injury was associated with the marked accumulation of iron-containing pigment in hepatocytes and Kupffer cells. Electron micrographs demonstrated the presence of whorl structures (myelin figures) within liver cell cytoplasm, and for the first time clearly illustrated the endocytotic expulsion of these membranous whorls from hepatocytes into the bile canaliculi and sinusoids. Other ultrastructural changes were similar to those previously reported in rat livers injured by several hepatotoxic substances. Mitochondria enclosed by or projecting into large non-lipid vacuoles were present in several experimental groups. The electron micrographs provide the most convincing evidence to date to support the hypothesis that myelin figures may be the vehicle whereby the cell rids itself of specific hepatotoxic substances.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0173-0835
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology
    Notes: In a study of the biochemical mechanisms of renal toxicity of acetaminophen, quantitative studies of the nonspecific kidney esterases were carried out in New Zealand white female rabbits. After the administration of a sublethal dose of 2.5 g/kg acetaminophen, four animals each plus four controls were sacrificed at 24 and 48 h. subsequent isoelectric focusing of kidney homogenate supernatants over a pH range of 3.5-8.0 showed marked changes in each of the groups. Zymograms of the nonspecific esterases in each group showed a characteristic pattern which deviated greatly from control animals. A morphological and histochemical examination of kidney sections from all animals showed no pathological changes in any of the kidneys. This would indicate that abnormal biochemical changes are being manifested in the kidney long before any morphological deviations. It would seem that this group of enzymes could provide a valuable market for early toxicological changes.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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