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  • Cell & Developmental Biology  (9)
  • 1980-1984  (8)
  • 1950-1954  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Structure, histochemistry, ontogenetic development, and regeneration of the ocellus of Cladonema radiatum dujardin (cnidaria, hydrozoa, anthomedusae) (1981)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 167 (1981), S. 313-331 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The ectodermal eyes, 45-55 μm in diameter, of the cnidarian hydrozoan Cladonema radiatum Dujardin possess a lens approximately 15 μm in diameter enveloped by an eyecup (retina). An overlying layer of intensely vacuolated distal process of the adjoining epithelial cells forms a transparent cornea. The eyecup is composed of three cell types: basal cells, melanin-containing pigment cells, and photoreceptor cells. The last two cell types occur in the ratio of approximately 2:1. Histogenesis of the eye both during ontogeny and regeneration is described from light and electron microscopic investigations. During ontogeny the cell types forming the retina are derived from a compact group of morphologically undifferentiated cells, but during regeneration a primordium is formed by regeneration cells. In both cases the lens is built from distal nonnucleated cytoplasmic portions pinched off from the pigment cells. The cornea is formed by distal lamellar processes of the ocellus adjoining the epithelial cells. Through EM-histochemical methods (silver impregnation and DOPA-oxidase reaction) the pigment of the chromatophores of the retina was identified as melanin.
    Additional Material: 25 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1051670306
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  • 2
    Electronic Resource
    Electronic Resource
    Structure and arrangement of zona glomerulosa cells in the bovine adrenalA paper by Weber submitted to the graduate faculty, University of Wisconsin, in partial fulfillment of requirements for the degree of Doctor of Philosophy. Published with the approval of the Director of the Wisconsin Agricultural Experiment Station. Project no. 622-V: Trichomoniasis and other reproductive diseases of cattle and Project no. 532: The endocrine relations in farm animals. (1950)
    New York, NY : Wiley-Blackwell
    Journal of Morphology 87 (1950), S. 393-415 
    Details
    ISSN: 0362-2525
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jmor.1050870302
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  • 3
    Electronic Resource
    Electronic Resource
    Three-dimensional reconstruction of a rat stage V Sertoli cell: III. A study of specific cellular relationships (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 167 (1983), S. 181-192 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Specific Sertoli-Sertoli and Sertoli-germ-cell contacts and/or junctions were investigated employing micrographs used to reconstruct serially a model of a rat stage V Sertoli cell. The Sertoli-Sertoli junctional contact areas occurred in a belt-like arrangement near the base of the Sertoli cell. This configuration is consistent with their proposed function as a sealing element limiting the passage of materials toward the tubular lumen. Sertoli ectoplasmic specializations also formed a continuous belt, or band, around the reconstructed cell at the junctional contact area. Eighteen Sertoli-Sertoli tubulobulbar complexes were found; some (12 in number) invaginated the reconstructed cell, while others (6) emanated from it. Of 37 round germ cells that were sectioned in their entirety and adjoined the reconstructed cell, 23 displayed desmosome-gap junctions with either the reconstructed cell or an adjoining cell. Since there were multiple junctions connecting some germ cells to Sertoli cells, the total number of junctions was much greater (35). Desmosome-gap junctions of the Sertoli cell were numerous connecting pachytene spermatocytes, less numerous connecting type B spermatogonia, and even less numerous connecting step 5 spermatids; and none was seen joining Sertoli cells with elongate spermatids. Most desmosome-gap junctions join germ cells to the body of the Sertoli cell at its basal aspect. Their numbers and position indicate that they play a role in the maintenance of the integrity of the seminiferous epithelium and may provide a route for cell-to-cell communication. Ectoplasmic specializations of the reconstructed cell were seen facing only 3 of 37 round germ cells, and 7 ectoplasmic specializations from adjoining Sertoli cells faced these germ cells, all of which were step 5 spermatids. That there were no ectoplasmic specializations facing pachytene cells indicates that ectoplasmic specializations are not acquired as these cells pass through Sertoli-Sertoli junctions, but are acquired later in spermatogenesis.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001670204
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  • 4
    Electronic Resource
    Electronic Resource
    Three-dimensional reconstruction of a rat stage V Sertoli cell: II. Morphometry of Sertoli-Sertoli and Sertoli-germ-cell relationships (1983)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 167 (1983), S. 163-179 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Sertoli-Sertoli and Sertoli-germ-cell configurational relationships were studied using morphometric techniques and direct measurements as obtained from micrographs used to reconstruct a model of a rat stage V Sertoli cell. Regional areas of the Sertoli cell surface, which faced germ cells, other Sertoli cells, or noncellular structures, were expressed as relative surface area percentages; and the absolute surface areas for these regional areas were calculated. The surface area of the reconstructed cell, in its unmagnified state, was found to be 12,163 μm2. Cell processes were enumerated and studied using morphometric techniques. The surface area of the reconstructed Sertoli cell facing germ cells and Sertoli cells was also determined. Five Sertoli cells showed extensive contact with the reconstructed cell at the level of the Sertoli-Sertoli junctional contact region. This contact region averaged 3.51 μm in width. The relative and absolute surface area of subsurface ectoplasmic specialization of the Sertoli cell that faced germ cells and other Sertoli cells was calculated, and the extent of penetration of step 17 spermatids into the Sertoli crypts was determined. Surface relationships of the reconstructed cell to cellular and noncellular elements were depicted on outline drawings of the Sertoli cell.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001670203
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  • 5
    Electronic Resource
    Electronic Resource
    Serum stimulation of potassium fluxes, ouabain binding, and sodium fluxes in quiescent chicken embryo fibroblasts (1980)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 103 (1980), S. 363-370 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Growth-contingent alterations in potassium and sodium fluxes, ouabain binding, and potassium ion content were examined following serum stimulation of quiescent, density-inhibited chicken embryo fibroblasts. Serum stimulation resulted in very rapid 1.5- to 1.8-fold increases in ouabain-sensitive potassium influx and lesser 1.4- to 1.5-fold increases in potassium efflux and sodium influx. Potassium influx stimulation was maximal after addition of 5-20% calf serum and was unaffected by cycloheximide inhibition of protein synthesis. Reflecting the slightly greater stimulation of potassium influx versus potassium efflux, potassium ion levels were 10-15% higher in serum-stimulated compared to unstimulated cells. Specific ouabain binding levels in stimulated and unstimulated control cells were initially similar, however, by four hours after stimulation a 40-50% increase in specific ouabain binding was observed. Incubation with ouabain was found also to inhibit later serum-stimulated hexose uptake and thymidine incorporation; this blockage may be a consequence of subnormal potassium levels rather than ouabain inhibition of the serum-stimulated potassium influx.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041030222
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  • 6
    Electronic Resource
    Electronic Resource
    Coordinate regulation of polypeptide chain initiation and elongation in rabbit reticulocytes (1984)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 118 (1984), S. 267-276 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: Under normal conditions, reticulocytes synthesize α- and β-globin polypeptides at equal rates. Incubation in the absence of hemin or under anoxia or hypertonic stress (100 mM excess NaCl) reduces the rate of protein synthesis to 30-50% of control levels. However, only hemin deprivation causes a reduction in polyribosome size and preferential inhibition of α-globin synthesis consistent with specific reduction in the rate of polypeptide chain initiation. Polyribosomal profiles are unaffected by anoxic or hypertonic stress and the ratio of α:β globin synthesis remains close to unity. Measurement of ribosome transit time indicates that anoxic or hypertonic stress causes a decrease in the rate of polypeptide chain elongation that varies with the degree of inhibition of protein synthesis. Ribosomes isolated from stressed cells exhibit a reduced ability to bind 35S-met-tRNAf, suggesting that the ability to form initiation complexes is also impaired. These results suggest that reticulocytes, unlike nucleated cell lines, can coordinately reduce rates of initiation and elongation in response to certain physiological stresses.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041180309
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  • 7
    Electronic Resource
    Electronic Resource
    Coordinate regulation of gluconeogenesis by the glucocorticoids and glucagon: Evidence for acute and chronic regulation by glucagon (1981)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 109 (1981), S. 83-90 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The coordinate regulation of gluconeogenesis by the glucocorticoids and glucagon in primary cultures of adult rat liver parenchymal cells has been studied. The results suggest that glucagon stimulation of glucose production from 3-carbon precursors is composed of at least two components which the glucocorticoids differentially affect. Glucagon treatment of hepatocytes results in an immediate increase in glucose production which is not blocked by cycloheximide and occurs in the absence of any detectable increase of phosphoenolpyruvate carboxykinase activity. This component appears to be regulated by a post-translational mechanism and involves redirection of carbon flow from glycolysis to gluconeogenesis. The second component is characterized by the need for long-term glucagon treatment. This increase in glucose production can be blocked by cycloheximide and is correlated with an increase in phosphoenolpyruvate carbooxykinase activity. The reaction that is accelerated by long-term glucagon incubation is located prior to the triose-phosphate level since long-term incubation with glucagon fails to increase glucose production from dihydroxyacetone any more than does short-term incubation. It is suggested that phosphoenolpyruvate carboxykinase rather than amino acid transport is the key pacemaker reaction in the long-term incubation since the direction and magnitude of the response for glucocorticoid and glucagon stimulation of glucose production is the same whether alanine or lactate is used as the 3-carbon precursor. The glucocorticoids exhibit an additive effect on glucagon-stimulated glucose production for the first component whereas they amplify the second component.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041090110
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  • 8
    Electronic Resource
    Electronic Resource
    Hormonal and nutritional factors influencing glycogen deposition in primary cultures of rat liver parenchymal cells (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 110 (1982), S. 300-303 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The effect of the glucocorticoids, insulin, and glucose concentration on glycogen deposition in adult rat liver parenchymal cells maintained in a chemically defined, serum-free medium has been studied. Increasing the medium concentration of glucose from 5.6 mM to 30.6mM in the absence of hormones increased cellular glycogen content from 6.5 to 51 μg of glycogen per mg of cell protein. Treatment of the cells with insulin increased the glycogen content by 15 to 30% at medium glucose concentrations above 10.6 mM. The addition of the synthetic glucocorticoid, dexamethasone, to the culture medium resulted in 40 to 105% increases in glycogen content at glucose concentrations greater than 5.6 mM. The addition of dexamethasone and insulin together in the culture medium resulted in an increase in glycogen content that was greater than the additive effect of each hormone alone. This established that glucose concentrations above 10.6 mM stimulate glycogen deposition in the absence of any hormonal stimulus. In addition, glucocorticoids directly stimulate glycogen deposition at glucose concentrations which are greater than physiological (5.6 mM).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041100313
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  • 9
    Electronic Resource
    Electronic Resource
    Glucagon and choleragen stimulation of glycogenolysis in primary cultures of adult rat liver parenchymal cells: Lack of involvement of the glucocorticoids (1982)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Cellular Physiology 110 (1982), S. 304-310 
    Details
    ISSN: 0021-9541
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Medicine
    Notes: The influence of glucagon, choleragen, and the adrenal glucocorticoids on glycogenolysis in primary cultures of adult rat liver parenchymal cells has been studied. Both glucagon and choleragen caused a twofold to threefold stimulation of glucose production from endogenous reserves of glycogen. The effect of glucagon on glucose production was noted at the earliest time point examined and the stimulation of glucose production was preceded by an elevation of cyclic AMP. Choleragen did not produce a significant stimulation of glucose production until 45 minutes after addition of the agent. Choleragen effects on glucose production were preceded by an elevation of cyclic AMP, but in contrast with glucagon, choleragen did not significantly elevate cyclic AMP until 30 minutes after addition to the culture. One ng of choleragen per ml of medium was sufficient to produce an effect on glucose production. Glucagon- or choleragen-treated cultures mobilized glycogen more rapidly than did untreated cultures incubated in glucose-free medium. In addition, both agents produced a stong inhibition of lactate production. Thus, the stimulation of glucose production by these agents was partially due to increased glycogen mobilization and partially due to redirection of carbon units from glycolysis. That glucose production in the hepatocytes is regulated in part by a cyclic AMP-dependent mechanism is strongly supported by the observation that both agents elevate cyclic AMP and cause an increase in glucose production and inhibition of lactate production. The possibility that the glucocorticoids participated in the regulation of glycogenolysis either in a direct or indirect (permissive) fashion was assessed. It was found that when the direct effect of the glucocorticoids on glycogenesis was taken into account, the glucocorticoids had no direct effects on glycogenolysis, nor did they alter the stimulation of glycogenolysis by glucagon or choleragen.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jcp.1041100314
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