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  • 1975-1979  (8)
  • Cell & Developmental Biology  (8)
  • Polymer and Materials Science
  • 1
    Digitale Medien
    Digitale Medien
    New York, NY : Wiley-Blackwell
    Journal of Morphology 156 (1978), S. 209-235 
    ISSN: 0362-2525
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: An ultrastructural comparison of mouse oocytes isolated at various stages of growth and meiotic competence has been carried out. Progressive changes in the nucleoli, ribosomes, mitochondria, endoplasmic reticulum, Golgi complex, and other organelles and inclusions of the oocyte have been examined as a function of oocyte size by transmission electron microscopy. The observations presented support the idea that growth of the mammalian oocyte involves not just tremendous enlargement of the cell, but extensive alterations in its overall metabolism as reflected in the ultrastructure of the oocyte at various stages of growth.
    Zusätzliches Material: 1 Tab.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 2
    ISSN: 0021-9541
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Biologie , Medizin
    Notizen: A variant subline of Chinese hamster cells (line CHO) was isolated that had increased resistance to detachment from the substratum. Comparisons between parental and variant cells of the complex carbohydrates liberated during trypsin detachment showed that the variant cells synthesized little or no hyaluronic acid. These cells also had reduced amounts of other complex carbohydrates in the cell periphery. However, parental and variant cells did not differ in morphology, growth control, or cyclic AMP concentration. Profound changes in the physical and chemical nature of the cell periphery, in themselves, evidently are insufficient to cause changes in many aspects of cell behavior.
    Zusätzliches Material: 4 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 3
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Single, isolated pancreatic islets of mice and rats were incubated for varying time intervals (0.5-60) minutes with high (300 mg%) and low (50 mg%) levels of glucose. The structural integrity of islets decreased progressively with time regardless of glucose concentration. Degeneration of islets was greatest after 60 minutes of incubation. The total amount of insulin released from cytologically intact mouse islets incubated with high glucose levels was always greater than that with low glucose except following 30 seconds of incubation when no difference was observed. Peaks of insulin secretion noted after 2 and 15 minutes of incubation were correlated with light microscopic and fine structural changes indicative of active secretion in β-cells, i.e., degranulation, granule margination. At 5 and 30 minutes of incubation many β-cells contained enlarged Golgi zones and abundant profiles of swollen rough endoplasmic reticulum containing pale, amorphous granular material presumably indicating insulin synthesis. Emphasis is placed on the desirability of correlating physiological and biochemical studies of isolated pancreatic islets with cytologic examination.
    Zusätzliches Material: 8 Ill.
    Materialart: Digitale Medien
    Bibliothek Standort Signatur Band/Heft/Jahr Verfügbarkeit
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  • 4
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 194 (1979), S. 159-179 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: A fine structural study of the normal rat vas deferens was undertaken utilizing perfusion fixation. Morphological features not previously appreciated were revealed using this technique of fixation, and included the following.The rat vas deferens exhibited a gross morphological and microscopic differentiation along its length: A proximal segment was characterized by a thin muscular wall, an epithelium of low height (comparable to that of the cauda epididymidis) and a distended lumen typically filled with an accumulation of sperm; a distal segment exhibited a thick muscular wall, a convoluted mucosa, and a pseudostratified columnar epithelium with long stereocilia extending into the lumen. The transition from the morphology typical of the proximal segment to that of the distal segment was gradual and progressive, marked by an increase in the mass of the muscular wall and in the height and ultrastructural complexity of the epithelium. Clear or “foamy” cells, characteristic of the cauda epididymidis, were observed in the initial centimeter of the vas deferens. Also, a cell type designated as “mitochondrion-rich” was observed in the distal vas segment. The structure of the small mitochondria in such cells, however, did not conform to the description of mitochondria in similar cells found in the human (Hoffer, '76). Intraepithelial macrophages containing residual accumulations which often resembled spermatozoan remnants in advanced stages of dissolution were present in all segments of the rat vas deferens, confirming in this species a spermiophagic role for such cells.
    Zusätzliches Material: 20 Ill.
    Materialart: Digitale Medien
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  • 5
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 191 (1978), S. 31-45 
    ISSN: 0003-276X
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Prolactin is known to enhance the uptake and metabolism of testosterone in male accessory sex organs and to increase the weight of accessory sex organs from castrated rats over those from controls treated with testosterone alone. The present study was directed toward defining fine structural changes detectable with scanning and transmission electron microscopy which might accompany such responses. Accordingly, rat ventral prostrate gland was examined from castrated animals which had received testosterone propionate and ovine prolactin singly or together, or which had received vehicle only. Unoperated ani-mals served as additional controls. Post-castration glandular atrophy was not influenced by prolactin treatment alone. Testosterone restored epithelial height, secretory product, Golgi complexes and rough endoplasmic reticulum, such that cellular and tissue morphology was generally indistinguishable from that of unoperated controls. Prostatic tissue from animals given testosterone and prolactin simultaneously exhibited pleomorphic, cytoplasmic apical projections which extended into the acinar lumen. Transmission electron microscopy demonstrated that these blebs were devoid of organelles and microvilli; scanning electron microscopy revealed that the blebs were highly wrinkled and more numerous than were the projections observed in tissue from animals treated with testosterone alone, or in tissue from unoperated controls. It is suggested that such blebbing may reflect enhanced apocrine secretion in prolactin/testosterone stimulated restoration of the prostate gland in castrated rats.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 154 (1979), S. 525-543 
    ISSN: 0002-9106
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: The effect of estradiol and/or testosterone upon secretion by seminal vesicle in castrated and intact rats was assessed in young adult Sprague-Dawley rats, using light microscopy (LM), transmission (TEM) and scanning (SEM) electron microscopy. Hormones were injected daily for ten days beginning ten days after castrations were performed. The normal rat seminal vesicle, as revealed by SEM, was characterized by a large saccular lumen with highly folded walls. Cell surfaces were covered with microvilli, or occasionally displayed a protruding, ruffled surface, sparsely covered with short microvilli. Cytology was normal in testosterone-treated animals. Estradiol treatment of castrated animals stimulated secretion by seminal vesicle epithelial cells as evidenced by the presence of normal secretory bodies, the presence of RER, and moderately hypertrophied Golgi complexes. These glands were not heavier than were glands from castrated, untreated animals, although the epithelial cells were significantly taller. Secretion was maintained in intact animals treated with estradiol, although glands were smaller and epithelial height was reduced. Estradiol and testosterone treatment in combination did not appear to have an additive effect on secretion, weight of the gland, or epithelial height. The following results support the hypothesis that estrogen-induced prolactin synthesis and release may be involved in the mechanism by which estradiol effected stimulation of seminal vesicle epithelium. Prolactin-treated, castrated animals exhibited focal areas of stimulated epithelium. In hypophysectomized animals (untreated controls), the seminal vesicle epithelium retained some secretory bodies and secretory fluid in the glandular lumen; epithelial height was taller than that in castrated controls. Estrogen treatment reduced the epithelial height to that of castrated controls; there was no evidence of secretion. This suggests that in the absence of anterior pituitary hormones, including prolactin, the stimulatory effect of estradiol on seminal vesicle epithelium was nullified. In adrenalectomized/castrated animals, estradiol treatment stimulated secretion in seminal vesicle epithelium just as in non-adrenalectomized/castrated animals. This indicates that the adrenal gland plays a non-essential role in the action of estrogen on seminal vesicle epithelium.
    Zusätzliches Material: 1 Ill.
    Materialart: Digitale Medien
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  • 7
    ISSN: 0002-9106
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Decidual tissue occurring within the human ovarian cortex was examined by light and electron microscopy. Of 21 ovarian specimens obtained at term (36-42 weeks of gestation), decidual cells were confirmed in each. Decidual cells were found within the tunica albuginea as single cells, in nodules, in polyps or in confluent sheets. Decidual cells exhibited several characteristics of cells engaged in secretory activity: abundant rough and smooth endoplasmic reticulum, numerous profiles of the Golgi complex and a large, euchromatic nucleus devoid of heterochromatin and displaying a prominent fibrous lamina. Peduncular protrusions at the periphery of the cell contained numerous dense bodies 0.4-0.9 μm in diameter. These dense bodies were bounded by a single membrane and contained granular subunits 30-60 nm in diameter. These granular subunits were observed in the process of apparent exocytosis, as well as free in the extracellular space. Secretory bodies and their granular content also were observed both in the region of the Golgi complex and partially extruded into peduncular processes. By far the greatest number of secretory bodies occurred within peduncular processes where they may be stored prior to release. Migration of a secretory body into a peduncular process and exocytosis from such a process appears to be an unusual mode of meocrine secretion, perhaps unique to decidual cells.
    Materialart: Digitale Medien
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  • 8
    Digitale Medien
    Digitale Medien
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 152 (1978), S. 29-43 
    ISSN: 0002-9106
    Schlagwort(e): Life and Medical Sciences ; Cell & Developmental Biology
    Quelle: Wiley InterScience Backfile Collection 1832-2000
    Thema: Medizin
    Notizen: Fine-structural features of ovarian decidual cells and their mode of secretion were examined by means of freeze-fracture microscopy. Unique cortical peduncular processes contained secretory vesicles within the expanded peduncle tip, the membrane-leaflets of which exhibited a particle-poor E face adjacent to the vesicle lumen and a P face containing a greater particle number. Exocytosis from attached peduncles involved release of vesicular profiles 40-55 nm in diameter; small particles 8.5-11.5 nm in diameter were also observed at degranulation sites. In fractures revealing the E face of the plasmalemma, cytoplasmic portals at the bases of peduncular stalks were distinguishable from endocytic vesicles.The frequent occurrence of reflexive gap junctions associated with peduncles was shown by freeze-fracture. However, there appeared to be no consistent spatial relationship between gap junctions, secretory peduncles, or sites of exocytosis. Freeze-fracture analysis of the topography of reflexive gap junctional profiles revealed that such gap junctions share basic similarities with intercellular gap junctions. These similarities include particle size (8-10 nm); number of particles within clusters (20-40); and the presence of 5-15 nm particle-free aisles. The finding in the present study of reflexive gap junctions occurring between peduncles and the cell soma, as well as between peduncles, suggests that the original definition of reflexive gap junctions as those existing between processes of the same cell should be broadened to include any gap junctional specialization formed between portions of the plasma membrane of one cell.
    Materialart: Digitale Medien
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