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  • 1
    Electronic Resource
    Electronic Resource
    Variations in immunocytochemical localization of cathepsin B and thyroxine in follicular cells of the rat thyroid gland and plasma TSH concentrations over 24 hours (1989)
    Springer
    Cell & tissue research 256 (1989), S. 355-360 
    Details
    ISSN: 1432-0878
    Keywords: Thyroid gland ; Cathepsin B ; Lysosomes ; Immunocytochemistry ; Diurnal rhythm ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Immunocytochemical localization of cathepsin B and thyroxine (T4) in follicular cells of the rat thyroid gland and plasma concentrations of thyroid stimulating hormone (TSH) were examined at six evenly spaced times over 24 h. By light- and electron microscopy, immunodeposits for cathepsin B were localized in cytoplasmic granules of various sizes, whereas those for T4 were detected mainly in larger granules of the cells and in the colloid lumen. The size and location of cytoplasmic granules showing immunoreactivity for cathepsin B and T4 in the cells varied over 24 h, corresponding to a change in plasma TSH concentrations. These immunopositive large granules appeared in the apical cytoplasm at 12.00 h, when the level of TSH was highest. At 20.00 h when the level of TSH was lowest, T4-positive granules almost disappeared, and cathepsin B-positive small granules were abundantly seen in the basal region. From 00.00 h to 08.00 h, these positive granules changed in the same manner as those seen from 12.00 h to 20.00 h, associated with an increase in plasma TSH levels. These results suggest that newly formed colloid droplets migrate from the apical to the basal regions. Cathepsin B may play a role not only in the degradation of thyroglobulin but in the maturation of thyroid hormones during the migration of the granules.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218892
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  • 2
    Electronic Resource
    Electronic Resource
    Twenty-four-hour variations in subcellular structures of rat type II alveolar epithelial cells (1989)
    Springer
    Cell & tissue research 256 (1989), S. 347-353 
    Details
    ISSN: 1432-0878
    Keywords: Lung ; Type II cell ; Subcellular structures ; Morphometry ; Crcadian rhythm ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Subcellular structures of type II alveolar epithelial cells in the rat lung were analyzed at six evenly spaced times over 24 h (light period: 06.00 h–18.00 h), using a morphometric technique. The cell volumes were maximal at 16.00 h and minimal at 08.00 h. The volume and surface densities of rough endoplasmic reticulum and mitochondria were low during the light period, and high during the dark period. Morphometric parameters of multivesicular bodies did not significantly fluctuate over 24 h, but they increased from 04.00 h to 08.00 h. The volume densities of lamellar bodies increased from 16.00 h to 20.00 h, and decreased from 00.00 h to 08.00 h. The change in numerical densities of lamellar bodies was inversely correlated to that in the volume densities. As shown by electron microscopy, small lamellar bodies predominated at 08.00 h, larger lamellar bodies increasing at 16.00h. Composite bodies often appeared at 08.00 h and 12.00 h. Type II cells thus appear to fluctuate, showing three phases over 24 h: formation, accumulation and secretion of lamellar bodies. In particular, it is noteworthy that the accumulation stage occurs during the resting phase of the rat, whereas the secretion stage occurs during its body-active phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00218891
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  • 3
    Electronic Resource
    Electronic Resource
    A morphometric study of the variations in subcellular structures of rat hepatocytes during 24 hours (1984)
    Springer
    Cell & tissue research 236 (1984), S. 305-315 
    Details
    ISSN: 1432-0878
    Keywords: Hepatocytes ; Rat ; Liver ; Circadian rhythm ; Morphometry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Subcellular structures of hepatocytes in periportal and perivenous zones were examined during 24 h. The volume, surface and numerical profile densities of cytoplasmic organelles were analysed morphometrically. Most subcellular structures in periportal and perivenous hepatocytes were subject to strong circadian variations. In hepatocytes from both zones, the volume densities of smooth endoplasmic reticulum (sER), mitochondria, lysosomes, peroxisomes, polysomes and lipid droplets demonstrated peak values at 16.00 h, 20.00 h or 00.00 h; trough values were at 04.00 h, 08.00 h, or 12.00 h, except for peroxisomes (16.00 h). However, the volume densities of glycogen granules and rough endoplasmic reticulum (rER) in periportal and perivenous hepatocytes exhibited maximal values at 04.00 h, 08.00 h or 12.00 h and minimal values at 20.00 h. The surface densities of sER, mitochondria, lysosomes and peroxisomes, and the numerical profile densities of mitochondria, lysosomes and peroxisomes in periportal and perivenous hepatocytes showed similar trends. These events suggest that membranes of the rER show a partial correlation with the sER, mitochondrial and lysosomal membranes during the 24-h span. This may involve the interaction between ribosomes and rER. Almost all cytoplasmic organelles examined displayed significant differences between periportal and perivenous hepatocytes, morphometrically and in fine structure, indicating that the morphofunctional variability of hepatocytes differs depending on the location in the liver acinus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00214231
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  • 4
    Electronic Resource
    Electronic Resource
    A morphometric study of developing pancreatic acinar cells of rats during prenatal life (1984)
    Springer
    Cell & tissue research 237 (1984), S. 117-122 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas, exocrine (rat) ; Fine structure ; Membrane dynamics ; Development (ontogenetic) ; Morphometry ; Zymogen granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The pancreatic acinar cells of rat embryos obtained at 15, 17, 19 and 21 days of gestation have been examined using fine-structural and morphometric techniques. Morphometric analysis demonstrates significant variations in the average volume of the cell, nucleus and cytoplasm, and the volume, surface and numerical densities of various cytoplasmic organelles during fetal life. In particular, the volume and surface densities of rER exhibit maximal values at 19 days of gestation, suggesting that secretory proteins are produced most actively at this time. Further-more, membrane continuity between the nuclear envelope and rER is frequently discernible in acinar cells, indicating that at this stage the rER is mainly derived from the nuclear envelope. Zymogen granules first appear at 17 days of gesstation. By 21 days, they occupy the greater part of the cytoplasm of the acinar cells, no polarity being seen in their distribution pattern. No direct evidence for the secretion of zymogen granules has been observed during fetal life. It therefore appears that membrane transport involved with intracellular movement of newly synthesized proteins from rER via the Golgi complex to zymogen granules occurs in one direction and lacks regulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229206
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  • 5
    Electronic Resource
    Electronic Resource
    A morphometric study of the 24-hour variations in subcellular structures of rat pancreatic acinar cells during the periweaning period (1984)
    Springer
    Cell & tissue research 237 (1984), S. 131-138 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas, exocrine (rat) ; Circadian rhythm ; Morphometry ; Periweaning period
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pancreatic acinar cells of rats obtained before (21 days of age) and after (31 and 42 days) weaning were morphometrically examined at six evenly spaced times during 24 h. Morphometric analysis demonstrated clear-cut variations in the average volume of the cell and nucleus, the incidence of binucleate acinar cells, and the volume and numerical densities of various cytoplasmic organelles during 24 h, at each stage. The daily mean values and variation of these parameters at 21 days clearly differed from those at 31 and 42 days. In particular, changes in the volume densities of rER and zymogen granules were bimodal at 21 days, whereas they were unimodal at 31 and 42 days. Moreoever, some parameters also differed between 31 and 42 days, the main difference being an 8 h time shift in the variation curves of the volume densities of rER and zymogen granules. These findings indicate that morphometric analysis of the subcellular structures of pancreatic acinar cells during 24 h can be used to determine their developmental stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229208
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  • 6
    Electronic Resource
    Electronic Resource
    Morphometric and fine-structural studies of rat pancreatic acinar cells during early postnatal life (1984)
    Springer
    Cell & tissue research 237 (1984), S. 123-129 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas, exocrine (rat) ; Ultrastructure ; Morphometry ; Development, ontogenetic ; Zymogen granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Pancreatic acinar cells of rats obtained at 1,2, 3, 5, 7 and 14 days of age were examined using fine structural and morphometric techniques. From 5 days of age onwards, the acinar cells were analysed twice per day, at 20.00 h and 08.00 h. The present study demonstrates changes in the average volume of the cell, nucleus and cytoplasm, and volume densities of various cytoplasmic organelles during the first two weeks after birth. During early postnatal life, the volume density of rER increases, whereas that of zymogen granules decreases. From 5 days of age onwards, the volume densities of these two organelles differ significantly at 20.00 h and 08.00 h. During the first 2–3 days after birth, inclusion body-like structures appear in the cytoplasm of acinar cells; they contain aggregated zymogen granules and, sometimes, amorphous structures or cytoplasmic organelles. These structures also occur in interstitial cells and cells located in the intercalated region between acinar and ductal epithelial cells. Serum level of α-amylase activity is high at birth, compared with other stages during the first three weeks. Degenerating acinar cells and cell debris can be seen in the acinar and ductal lumina during these stages, a feature suggesting holocrine secretion. Cellular polarity appears to be incomplete during the first two or three days after birth.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00229207
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  • 7
    Electronic Resource
    Electronic Resource
    Quantitative analyses of atrial myoendocrine cells and plasma atrial natriuretic peptides (ANP) of the rat with special reference to the twenty-four-hour variations in secretory granules and plasma ANP concentrations (1988)
    Springer
    Cell & tissue research 254 (1988), S. 133-137 
    Details
    ISSN: 1432-0878
    Keywords: Atrial myoendocrine cells ; Morphometry ; Plasma atrial natriuretic peptides ; Circadian variations ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Subcellular structures of atrial myoendocrine cells in the rat heart and plasma concentrations of atrial natriuretic peptides (ANP) were examined at six evenlyspaced time points over 24 h, using morphometric techniques and radioimmunoassay. Myofibrils and mitochondria of the cells occupied 73.3% of the cytoplasm; 2% of the cytoplasm was occupied by secretory granules, rough endoplasmic reticulum and Golgi complexes, structures characteristic of endocrine cells. Plasma ANP concentration was maximal at 08.00 h, when the individual volume of secretory granules was minimal. The numerical density of secretory granules was increased at 12.00 h. The plasma ANP concentration was minimal at 20.00 h, when the numerical density was minimal and the individual volume was maximal. The fluctuation in plasma ANP concentrations over 24 h was thus parallel to that in the numerical densities of secretory granules and inverse to that in individual volumes. These results suggest that in rats the secretory activity of atrial myoendocrine cells increases at the beginning of the resting period, whereas it decreases at the beginning of the active phase.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00220026
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  • 8
    Electronic Resource
    Electronic Resource
    Twenty four hour variations in subcellular structures of rat pancreatic islet B-, A- and D-cells, and of portal plasma glucose and insulin levels (1988)
    Springer
    Cell & tissue research 253 (1988), S. 337-345 
    Details
    ISSN: 1432-0878
    Keywords: Pancreas, endocrine ; Morphometry ; Plasma glucose ; Plasma insulin ; Circadian variation ; Rat (Wistar)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Variations in stomach weights, plasma glucose and insulin levels in the portal vein, and in subcellular structures of rat pancreatic islet B-, A- and D-cells were examined over 24 h. The variation in stomach weights paralleled plasma glucose levels, indicating that the levels may be influenced by intestinal glucose absorption. Plasma insulin levels increased from the late dark to the early light periods, whereas they decreased from the late light to the early dark periods. The variation in plasma insulin levels was in the opposite sense to that in the relative numbers of B-cell granules. The decrease in the relative numbers of A-cell granules occurred between the late dark and early light periods. The relative numbers of D-cell granules decreased before and after the decreases in B- and A-cell granules. The variation in D-cell granules appears to correspond to the inhibitory effect of somatostatin. The relative amounts of rough endoplasmic reticulum (rER) in each cell varied in a reciprocal manner to those of B-cell granules. Moreover, the variation in plasma insulin levels coincided with variations in rER of hepatocytes and pancreatic acinar cells. The changes in rER of each cell may correlate with the trophic effect of insulin.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222290
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