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  • 1
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 2 (1985), S. 0 
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The role of the pineal in regulating the oncogenic processes was explored in Sprague-Dawley female rats by comparing incidence and growth of mammary tumors in animals subjected to superior cervical ganglionectomy (SCGx) or blinding and anosmia (BAs) with that of intact rats treated with 7–12- dimethylbenz(a)anthracene (DMBA). The surgery was performed at the age of 56 days, 1 day following the administration of the carcinogen. Growth of mammary tumors was studied, and 15 weeks later the rats were sacrificed by decapitation and the activity of the pineal hydroxyindole-O-methyltransferase (HIOMT) was determined. Carcinostatic effects of similar magnitude were present in both SCGx and BAs groups as evident from tendency toward reduced tumor incidence and decreased total tumor mass. Ganglionectomized rats developed significantly smaller numbers of tumors than intact control animals. A trend toward reduced tumor number and increased tumor regression was evident in the BAs group. Although there was no significant difference in tumor volumes among the groups, BAs animals showed a distinct trend toward smaller tumor volumes at the termination of the experiment. Despite similar carcinostatic tendencies, SCGx rats had significantly lower HIOMT activity than BAs animals. The possible existence of multiple carcinostatic mechanisms in BAs and SCGx rats is discussed.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 166 (1976), S. 235-240 
    ISSN: 1432-0878
    Keywords: Pituitary ; Pars distalis ; Chromophobe ; Reptile ; Electron microscopy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Chromophobes of the pars distalis in young Chelydra serpentina have sparse cytoplasm with no specific granules; however, many cytoplasmic filaments are present. The chromophobes are connected to the other cell types by desmosomes, while different types of junctional specializations occur between adjacent chromophobes. Cytoplasmic filaments traverse the cytoplasm in a random manner and terminate on both the junctional complexes and the nuclear envelope. It is proposed that, in addition to providing a structural framework, the chromophobes may be involved in integrating cellular responses of the parenchyma to changes in the endocrine milieu.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Fetal decapitation in utero has enabled us to study the role of fetal pituitary hormones in the development of the fetal testis. Testes from males decapitated near 80 days of gestational life and later delivered at 150 days were smaller than normal and about one-tenth the normal weight. The size of the seminiferous tubules was similar in both groups; however, the number of Leydig cells seemed reduced. In addition, the Leydig cells of the experimental group contained smaller mitochondria with reduced tubular cristae, fewer lipid droplets, and reduced agranular endoplasmic reticulum. Androgen production was inhibited. Measured by radioimmunoassay, the testosterone level in the umbilical vein was 329 ± 82 pg/ml in six decapitated fetuses, 412 ± 62 pg/ml in ten normal fetuses. The level in the umbilical artery was 328 ± 56 pg/ml in five decapitated fetuses, 658 ± 140 pg/ml in normal fetuses. These studies suggest that chronic deprivation of fetal pituitary hormones inhibits the growth and development of the testis in general and of the Leydig cells in particular.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, N.Y. : Wiley-Blackwell
    Journal of Cellular Biochemistry 22 (1983), S. 111-120 
    ISSN: 0730-2312
    Keywords: mitoxantrone ; nucleic acid synthesis ; breast tumor cell line ; uridine ; thymidine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Chemistry and Pharmacology , Medicine
    Notes: Mitoxantrone exerts growth inhibitory effects, suppresses [3H]-thymidine as well as [3H]-uridine incorporation, and induces ultrastructural alterations in T-47D human breast tumor cells. At low concentration (10-9M) the drug induced little effect on cell proliferation; cell growth kinetics were inhibited at a concentration of 10-5M. [3H]-thymidine and [3 H]-uridine incorporation declined rapidly at the concentrations tested (10-9, 10-7, and 10-5 M), revealing a potent effect on metabolic activity of the cultured cells. The sharpest decline in DNA and RNA synthesis occurred within the first 2 hr of drug treatment. Serial ultrastructural examinations indicated definitive alterations in chromatin structure, disintegration of nucleolar components as early as 2 hr after drug treatment, and complete segregation of nucleolar components following 8-hr exposure to concentrations of the drug between 10-5 and 10-7 M. A distinct increase in the density of mito-chrondrial matrix was evident. The in vitro data presented in this report demonstrate the growth inhibitory and antimetabolic effects of mitoxantrone on human breast tumor cells and suggest that the drug may be a promising antitumor agent.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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