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  • Electronic Resource  (25)
  • Cell & Developmental Biology  (25)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 181 (1975), S. 149-169 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The previously described ability of reserpine and parachlorophenylalanine to induce the accumulation of lipid droplets in ventricular cardiac muscle cells of the bat was investigated. Lipid droplet accumulation was assessed qualitatively by light microscopy and quantitatively by morphometric analysis of electron micrographs. An hypothesis that the action of the drugs was an indirect one, mediated by the cardiac adrenergic innervation, was framed and tested. Lipid droplet accumulation occurred during a time of intense sympathetic activity, that of arousal from hibernation. The ability of the two drugs to produce the effect was antagonized by prior sympathectomy with 6-dopamine. The effect was mimicked by administration of exogenous norepinephrine together with inhibitors of its catabolic enzymes, monoamine oxidase and catechol-omethyl transferase. These observations are all consistent with the initial hypothesis and raise the possibility that endogenous norepinephrine in the cardiac sympathetic innervation might be, at least potentially, auto-toxic.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 193 (1979), S. 257-267 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: A highly specific serotonin binding protein (SBP) has been found in serotonergic neurons in both brain and gut. This protein has an extremely high affinity for serotonin and may be a storage protein. Serotonin is found in many endocrine cells, including parafollicular cells of the sheep thyroid, as well as in neurons. SBP is also present in sheep thyroid. The present study was done to localize the protein in the gland. Thyroid glands were divided into five segments. Concentrations of serotonin and SBP, as well as parafollicular cell volume were measured in each. Serotonin was assayed by enzymatic conversion to melatonin using tritiated S-adenosylmethionine. SBP was assayed by molecular sieve chromatography on sephadex G-50. The relative volume of parafollicular cells was obtained by stereological analysis of electron micrographs. Experiments were also done to demonstrate these cells by histofluorescence and radioautography following incubation with tritiated 5-hydroxytryptophan. Good correlations were found between serotonin and SBP concentrations, and parafollicular cell volume. These peaked in the rostro-central portion of the gland and were minimal at the poles. We conclude that thyroid SBP is probably localized in parafollicular cells.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Electron microscope immunocytochemistry was used to determine the intracellular localization and distribution among follicular elements of four peptides: calcitonin, somatostatin, calcitonin gene-related peptide (CGRP), and substance P in the thyroid glands of bats captured in the prehibernation phase of their annual life cycle. Previous studies have shown that this period of the hibernation - activity cycle is characterized by the accumulation and storage of secretory granules in parafollicular cells. Sites of binding of primary antisera to each of the four peptides were identified by means of affinity-purified secondary antisera directly coupled to colloidal gold particles. Calcitonin and somatostatin immunoreactivities were found in all parafollicular cells examined and in every secretory granule within these cells. CGRP was also found in all parafollicular cells examined (n = 75) but only in about half of their secretory granules. In contrast to these peptides, substance P immunoreactivity was not found in any parafollicular cells, but was localized exclusively in nerve endings within the basement membrane of the follicle.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 226 (1990), S. 471-480 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The distribution and cellular localization of the glycoprotein laminin were investigated by light and electron microscopic immunocytochemistry in the adult murine pituitary gland. Immunoblots confirmed that laminin was the only protein in the pituitary gland of the adult male mouse to react with antilaminin serum. Laminin immunoreactivity was demonstrated at the light microscopic level simultaneously with that of β-follicle stimulating hormone (β-FSH) and β-luteinizing hormone (β-LH). In addition to its distribution is basal laminae, laminin immunoreactivity was coincidently expressed in gonadotrophs with the immunoreactivities of β-FSH and β-LH. Electron microscopic immunocytochemistry was employed on aldehyde-fixed sections embedded in L.R. White. Sites of binding of primary antisera to laminin were identified with affinity-purified secondary antisera directly coupled to 20 nm particles of colloidal gold. Three antisera recognizing laminin were compared and found to result in an identical pattern of immunoreactivity. Laminin was found extracellulary only in formed basal laminae in all three lobes of the pituitary and was not found in extracellular matrices of connective tissue. Laminin immunoreactivity was also found intracellularly in gonadotrophs but in none of the other endocrine or non-endocrine cells of the anterior lobe. Within gonadotrophs, only secretory granules were labeled. The majority, but not all, secretory granules were labeled in each of the gonadotrophs examined, and the proportion of granules labeled with laminin could not be increased by doubling the concentration of anti-laminin serum. Laminin immunocreactivity segregated with the subset of secretory granules containing β-FSH. In contrast, laminin immunoreactivity was absent in the smaller subset of secretory granules that contain serotonin. No secretory granules were labeled within the endocrine cells of the intermediate lobe, nor within secretory granules of neural elements in the posterior lobe.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 178 (1974), S. 599-615 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The intercalated discs of the myocardium from the active and hibernating bat hearts were investigated by means of electron microscopy and use of lanthanum and horseradish peroxidase as tracers. The discs are composed of four zones: intermediate junctions, desmosomes, nexuses, and undifferentiated areas. Of particular interest are the two different types of nexuses. Nexus I without lanthanum displays a 150 Å overall width and an apparent 80 Å intercellular space, ranges from 0.5 to 4.0 μ in length, and is seen in the longitudinal segments of the intercalated disc. With application of lanthanum, however, nexus I shows that the tracer has penetrated a 20 Å gap junction and resembles nexus II. Nexus II with and without lanthanum has a 200 Å overall width and a gap junction of about 20 Å, is generally less than 0.3 μ in length, and is found on the transverse or oblique segment of the intercalated disc. Both nexuses I and II seem to block the passage of peroxidase. The plasma membranes of nexus I may have a different molecular organization from those in nexus II as reflected by their contrasting response to fixation and/or staining. Combinations of the various junctions show that the zones of adhesions (intermediate junctions and desmosomes) are adjacent to the regions of possible lowered resistance (nexus I and II). These findings suggest that adhesion sites insure the proper connection and functioning of the nexuses and support the electrical observations that the heart forms a “physiological syncytium”.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 215 (1986), S. 51-58 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Previous studies have demonstrated the uptake of exogenous and storage of endogenous 5-hydroxytryptamine (5-HT) in parenchymal cells of the anterior pituitary. The present experiments were undertaken to test the hypothesis that the endogenous 5-HT of the anterior lobe of the pituitary is costored with β-luteinizing hormone (β-LH) within the same secretory granules of gonadotrophs. Electron microscope immunocytochemistry was used to detect 5-HT and β-LH immunoreactivities in the anterior pituitary glands of mice and bats. Primary antisera generated in different species of animals to these two antigens were localized with appropriate species-specific secondary antisera coupled to colloidal gold particles of different sizes. This enabled 5-HT and β-LH immunoreactivities to be demonstrated simultaneously on ultrathin sections of fixed anterior lobe tissue mounted on electron microscope (EM) grids. In both bats and mice 5-HT immunoreactivity, identified by immunostaining of β-LH, was found in gonadotrophs, and in no other cell type. Within gonadotrophs about 25% of the secretory granules were labeled by antisera to both 5-HT and β-LH, although 100% of granules reacted with the antiserum to B-LH. No secretory granules were found that were immunostained only by the antiserum to 5-HT. It is concluded that endogenous 5-HT may be a normal constituent of mammalian gonadotrophs and that it is colocalized with β-LH in at least a subset of the secretory granules of these cells. It cannot yet be concluded that gonadotrophs synthesize 5-HT as well as taking it up from the ambient medium. The function of 5-HT in the pituitary remains unknown; however, the costorage of 5-HT and β-LH in the same secretory granules would seem to be a mechanism to ensure the simultaneous release of the two substances by exocytosis.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The effect of the administration of p-chlorophenylalanine on the fine structure of the ventricular cardiac muscle of active and hibernating bats was studied. The concentration of norepinephrine in the bat heart was also measured. In the active animal, p-chlorophenylalanine induced a striking increase in the size and number of lipid droplets. Moreover, the lipid droplets exhibited an intimate association with mitochondria. The mitochondria in such associations showed extreme variations in form but exhibited normal arrangement of cristae. p-Chlorophenylalanine also induced a slight increase in the number of glycogen granules but no other effects were apparent. During hibernation, the administration of p-chlorophenylalanine failed to produce a change in either the size or number of lipid droplets. The concentration of norepinephrine in the heart of active and hibernating bats was not altered by the injection of the drug. The present findings indicate that lipid accumulation in ventricular myocardium following injection of drugs is not necessarily the result of depletion of cardiac stores of norepinephrine.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 177 (1973), S. 15-22 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Histologic examination of metaphyseal bone of rats intoxicated with elemental phosphorus showed that inhibition of osteocytic osteolysis and chondrolysis account for widening of trabeculae and retention of the chondroid core. These changes are reflected in increased radiographic density and abnormal remodeling.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 184 (1976), S. 133-145 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Multiply ciliated follicular cells have been observed in developing thyroid glands in dogs. These cells are prominent three weeks prior to the expected date of birth but become progressively less common as development proceeds. After birth only rare isolated cilia remain. No evidence of removal of cilia by autophagy or loss into colloid was found. It is concluded that cilia are probably no longer formed by mature cells and that those already present are diluted out by progressive division of mature follicular cells.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    The @Anatomical Record 192 (1978), S. 215-224 
    ISSN: 0003-276X
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: The role of biogenic amines in the activation of thyroid follicu-lar cells by thyrotropin (TSH) was studied. 5-hydroxytryptamine (5-HT) was chosen as the amine to study and apical pseudopod formation, assessed by scanning electron microscopy, was used as the index of follicular cell activation. All experiments were done on dogs. TSH and 5-HT were both potent inducers of pseudopod formation. The action of TSH but not that of 5-HT was antagonized by the amine depleting drug reserpine. Reserpine depleted the thyroid of 5-HT in newborn, adolescent, and adult dogs. It is concluded that one or more biogenic amines, such as 5-HT, are probably involved in follicular cell activation by TSH.
    Additional Material: 1 Tab.
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