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  • Life and Medical Sciences  (8)
  • 1985-1989  (8)
  • 1987  (5)
  • 1986  (3)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 131 (1987), S. 29-35 
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The compensatory growth of the kidney which is induced by unilateral ne-phrectomy is a highly regulated process resulting principally in hypertrophy of the remaining kidney. The events which regulate this process are unknown. We have examined the levels of transcripts for the proto-oncogenes, myc, H-ras, K-ras, and fos, and the cellular genes, H4 histone, ornithine aminotrans-ferase, and gamma-glutamyl transpeptidase, following unilateral nephrec-tomy in the rat. The pattern of expression of c-myc, c-H-ras, and c-K-ras during compensatory growth of the kidney differs from the pattern of expression of these proto-oncogenes during liver regeneration, in which, unlike the kidney, hyperplasia rather than hypertrophy predominates. The lack of change in the abundance of these proto-oncogene transcripts following unilateral nephrec-tomy suggests a primary relationship between the expression of these proto-oncogenes and DNA synthesis and indicates there may be separate signals for cell growth, one to double cell size and one to replicate DNA. Increased mRNA transcripts for the enzymes ornithine aminotransferase and gamma-glutamyl transpeptidase were induced in the contralateral kidney after ne-phrectomy. The time course of expression for these two enzymes differs. The early expression of the gamma-glutamyl transpeptidase gene may indicate an involvement of this glutathione-metabolizing enzyme during renal compensatory growth, while the function of the delayed increase in ornithine amino-transferase transcripts in the remaining kidney is not apparent.
    Additional Material: 4 Ill.
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  • 2
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The osteopetrotic, microphthalmic (mi/mi) mouse lacks functional osteoclasts and has also been reported to be deficient in mast cells and natural-killer (NK) cells. The later deficiencies could be secondary to the osteopetrotic marrow, or a direct result of the mi allele. Therefore, heterozygotes were examined for these cell types, since these mice do not exhibit osteopetrosis. Adult +/mi animals have approximately 50%, and mi/mi animals examined by histologic techniques or tissue histamine levels have 0-10%, of the peritoneal, dermal, and intestinal mast cells compared with that of +/+ animals. Leukocyte histamine, indicative of the number of basophils, demonstrates the same pattern. Histamine content per mast cell in +/+ and +/mi animals is identical. The number of large granular lymphocytes (LGL) in splenic leukocyte preparations from +/mi animals is 50% that of +/+ animals, and these cells are undetectable in preparations from mi/mi mice. NK activity against YAC-1 cells paralleled the number of LGL present. The resorptive response of neonatal calvaria to parathyroid hormone was delayed in the case of cultured +/mi bone compared with that of +/+ bone, but the final rate of calcium release was identical. These data indicate that (1) the presence of one mi allele can affect the development of four distinct cell types, and (2) osteopetrosis alone does not account for the lack of mast cells, basophils, and NK cells in mi/mi mice.
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  • 3
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 15 (1986), S. 43-56 
    ISSN: 0148-7280
    Keywords: calcium ; ultrastructure ; motility ; respiration ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rapid cooling (cold shocking) of washed ejaculated ram sperm to 0°C irreversibly reduced motility, tail beat frequency, and respiration and increased the uptake of 45Ca2+. The plasma membranes were removed from the sperm head, and the acrosomes were detached from the nuclei. The plasma membranes of the middle piece were removed, and the mitochondria contained pale and expanded cristae, similar in appearance to ATP-deprived mitochondria in the “condensed” configuration. The presence of 2.0 mg/ml phosphatidylcholine (lecithin) in the medium prevented ultrastructural damage on cold shock, and the motility, tail beat frequency, respiratory rate, and calcium uptake were maintained at levels similar to washed sperm. As the “protective” effect of phosphatidylcholine against cold shock was maintained to a certain extent after rewashing and centrifuging the sperm prior to cold shock, the interaction of phosphatidylcholine with ram sperm membranes may be fairly “tight” and not easily disrupted.
    Additional Material: 14 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 4 (1986), S. 65-70 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Recent studies have yielded new insights into the critical importance of adequate vitamin D3 intake and metabolism. Investigations of the actions of 1,25-dihydroxyvitamin D3 (calcitriol) on novel target tissues has revealed that this hormone has functions other than its recognized action in regulating blood calcium and phosphate levels. Reports have characterized calcitriol receptors and activities in organs and tissues as diverse as pancreas, skeletal and heart muscle, blood cells, brain, skin, pituitary, parathyroid, kidney, bone and intestine. These studies suggest functions for calcitriol as varied as the regulation of insulin and prolactin secretion, muscle contractility, immune cell metabolism, melanin synthesis and differentiation of blood cells. This information may ultimately help us to understand the etiologies of several kinds of organ dysfunction and lead to the development of tissue-specific agents for new therapies.
    Additional Material: 2 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 17 (1987), S. 131-144 
    ISSN: 0148-7280
    Keywords: spermatogenesis ; nucleus ; testis ; acridine ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: A procedure is presented for rapid, quantitative evaluation of cell and nuclear types present in the male gonad of the sea urchin. Vitally stained whole mounts of tissue fragments or dissociated cells are prepared, which reveal detailed 3-dimensional chromatin patterns and enough cytoplasmic features to provide reliable markers for most of the somatic and germ line cell types. Representative cellular morphologies are described. Nuclear volume changes during spermatogenesis are quantified. Spermatid nuclei contain an apparently interconnected network of heterochromatin. Regions relatively devoid of chromatin decrease in size as nuclear condensation proceeds and spherical nuclear shape is maintained. The major decrease in nuclear volume occurs prior to the late spermatid stage. The volume of the spermatozoan nucleus is achieved by the smallest late spermatid nucleus before the change from spherical to conoid morphology. The relationship of this morphological transition to sperm histone dephosphorylation is discussed.
    Additional Material: 8 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    BioEssays 4 (1986), S. 172-176 
    ISSN: 0265-9247
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Nucleosome positioning refers to sequence-specific locations for histones interacting with the nucleic acid. Examples of occurrence of this phenomenon, its possible mechanisms and its significance are presented.
    Additional Material: 2 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Gamete Research 17 (1987), S. 355-373 
    ISSN: 0148-7280
    Keywords: motility ; respiration ; calcium ; ultrastructure ; Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology
    Notes: Rapidly cooling (cold shocking) washed cauda boar sperm irreversibly reduced motility and respiration and greatly increased the uptake of 45Ca2+; the plasma membranes were removed and the acrosomes detached from nuclei. The motility, respiration, and calcium uptake of the less mature caput sperm were largely unaffected; and there was little damage to the ultrastructure. This indicates that boar sperm becomes less resistant to cold shock as they mature in the epididymis.The oxygen uptake, glucose breakdown, and lactic acid production of control caput sperm was less than that of cauda sperm. This suggest that the maturation of sperm in the epididymis of the boar involves an increase in both the glycolytic and oxidative phases of glucose metabolism.The presence of 2.0 mg/ml phosphatidylcholine (lecithin) in the medium prevented ultrastructural damage to cauda sperm on cold shock, and motility and respiration were maintained at levels similar to those of control sperm. Although the presence of phospholipid reduced the large calcium influx following cold shock, it was still greater that that of control sperm.The “protective” effect against cold shock was not maintained after rewashing the sperm free of phosphatidylcholine prior to cold shock, indicating a fairly “loose” interaction of the phospholipid with boar sperm membranes that was easily disrupted.
    Additional Material: 17 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal of Electron Microscopy Technique 5 (1987), S. 217-218 
    ISSN: 0741-0581
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Natural Sciences in General
    Additional Material: 2 Ill.
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