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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Histochemistry and cell biology 86 (1987), S. 551-557 
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to study the distribution of mitochondrial cytochromes P-450 in porcine adrenal glands, the glands of anesthetized pigs were fixed in situ. Polyclonal antibodies against two cytochromes P-450, i.e., C27 sidechain cleavage enzyme and 11 beta-hydroxylase, were used to study the distribution of these enzymes in cryosections of the adrenal cortex. Ultrathin cryosections were evaluated by both protein-A/gold/silver immunocytochemistry and immunielectron microscopy using double labeling with protein-A/colloidal-gold. At light microscopy, the two cytochrome P-450 enzymes were found to be broadly distributed in both the fasciculata and glomerulosa zones of the adrenal cortex. Quantitative immunoelectron microscopy revealed that both enzymes were localized only in mitochondria, in which they were present on the inner aspects of the inner mitochondrial membrane. Both cytochromes P-450 were demonstrable in all of the mitochondria examined, and statistical evaluation of the ratios of the two enzymes present in individual mitochondria yielded a normal distribution curve. Since no evidence was found for the preferential localization of either enzyme in a special population of mitochiondria, we conclude that all mitochondria of the adrenal cortex contain both enzymes. We discuss implications of these findings with respect to the regulation of steroidogenesis.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In the present study, we have localized by immunocytochemistry at the LM and EM level, procollagen type III (PIIIP), fibronectin (FN) and heparan sulfate proteoglycan (HSPG). Intracellularly, PIIIP was observed in both parenchymal and endothelial cells. In parenchymal cells, PIIIP was found in Golgi derived vesicles. This observation suggests that PIIIP synthesis is a normal function liver parenchymal cells. In endothelial cells, vesicles, which could not be identified, were seen to contain PIIIP. This result does not allow to conclude, whether sinusoidal endothelial cells secrete or take up PIIIP. Extracellularly, PIIIP was present around portal and central veins, in the space of Disse and between adjacent parenchymal cells. In the space of Disse, almost all interstitial collagen fibrils reacted with the anti PIIIP antibodies. This observation leads to the conclusion that most fibrils of the space of Disse contain type III in addition to type I collagen molecules. By immunofluorescence, FN was seen mainly along the sinusoids in discrete dots. By EM, FN was found to be present in diffuse material closely associated with the sinusoidal membrane of the parenchymal cells and in strands connecting adjacent parenchymal cells, parenchymal and endothelial cells or parenchymal cells and collagen fibrils. FN was also present in vascular and ductular basal laminae. Strong HSPG reaction was observed around bile ducts. Moderate reaction was seen around blood vessels and in the space of Disse. In the latter location, the ultrastructural distribution of HSPG resembles that of FN, i.e. HSPG is present in diffuse material and in strands.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In Basommatophora medio-dorsal bodies (MDB) are closely attached to the cerebral ganglia, in which, just underneath the bodies, groups of Gomori-positive neurosecretory cells (MDC) occur. It has been suggested that the MDB-cerebral ganglion complex should be regarded as a neuro-endocrine association. In the present study the morphological relation between MDB and the ganglion is histochemically and ultrastructurally investigated in Lymnaea stagnalis, Ancylus fluviatilis, Australorbis glabratus and Planorbarius corneus. Histochemical tests showed the paraldehyde-fuchsin positive material of fibers in the MDB to be different from the neurosecretory material (NSM) in the MDC. At the ultrastructural level no penetration of nerve cell processes through the perineurium, separating the MDB from the ganglion, into the medulla of the MDB was observed. However, excepting for Lymnaea, the perineurium at these places shows particular differentiations. In the medulla of the MDB granule laden profiles (granule ø 700–900 Å) occur. They appeared to be processes of MDB cells. From these results it is concluded that the medulla of the MDB should not be regarded as a “neurosecretory neuropile”. Apparently, the MDB-cerebral ganglion complex is no neuroendocrine association. Probably the MDB is an endocrine organ. The small electron dense granules of the profiles in the medulla were also found in the MDB cell bodies. They are thought to represent a secretion product. The close morphological relation between MDB and cerebral ganglion may be connected with the origin of the MDB cells from perineural elements.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 155 (1974), S. 135-154 
    ISSN: 1432-0878
    Keywords: Exocrine pancreas ; Frog ; Ultrastructure ; Intracellular transport ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The route by which secretory proteins are transported in the frog exocrine pancreas cell was investigated by an ultrastructural and electron microscope autoradiographic analysis of in vivo 3H-leucine labelled tissue. The ultrastructure of the cell is characteristic of serous epithelial cells and resembles that of mammalian exocrine pancreas cells very closely. Autoradiographic results revealed that the proteins, after being synthesized in the rough endoplasmic reticulum (RER), are transported through the Golgi cisternae to condensing vacuoles which subsequently change into secretory granules. The determination of the timing of this transport was complicated by a very slow turnover of leucine in the frog. Nevertheless, by a semi-quantitative approach, some time characteristics could be estimated: about 11 min after the onset of their synthesis the proteins enter the Golgi system, and about 25 min later the condensing vacuoles. Secretory granules become labelled between 60 and 120 min. These results are discussed, also in relation to the transport route and kinetics in mammalian tissue.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Cell & tissue research 167 (1976), S. 147-165 
    ISSN: 1432-0878
    Keywords: Frog exocrine pancreas ; In vitro ; Intracellular transport ; Temperature sensitivity ; Autoradiography
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Frog pancreatic tissue was pulse-labelled in vitro with 3H-leucine and protein transport was studied in exocrine cells by electron microscope autoradiography. The proteins appeared to be synthesized in the RER and transported to the secretory granules along a similar route and with the same velocity as previously described under in vitro conditions. Evidence was obtained for the involvement of the vesicular and tubular elements at the periphery of the Golgi system in transferring protein from the RER to the Golgi cisternae. Kinetics of the release of newly synthesized proteins from the RER and their appearance in the condensing vacuoles are discussed and related to results reported from other tissues. The transport velocity in this poikilothermic system was studied in relation to the incubation temperature and compared with results reported from its mammalian counterpart. At temperatures between 20 and 30° C intracellular protein transport occurs faster in the frog than in the Guinea pig pancreas. At higher temperature the transport process was severely disturbed in the frog.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 152 (1978), S. 391-417 
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Copulation forced the mucous cells of rat bulbo-urethral (Cowper's) glands to accelerate their secretion. Determination of macromolecularly-bound hexose as a measure for the mucous contents of the glands and light and electron microscopic observations showed that the glands lost their mucus within four hours after the start of copulation. Secretion of the mucous granules occurred in an exocytotic fashion. This led to the formation of extensive secretory canaliculi extending to the cell bases. Successive mutual coalescing of the mucous granules formed intracellular secretion channels running from the secretory cell surfaces deeply into the cells.The vast reduction of cellular volume by loss of the numerous secretory granules and the sudden addition of large amounts of granule membrane to the cell membrane caused a considerable enlargement of the cell surface. The superfluous cell membrane was stored temporarily in tufts of long microvilli. The appearance of endocytotic structures and lysosomes was interpreted as indicative of internalization and breakdown of cell membrane. Between four and six hours after copulation cytoplasmic volume and size of RER and Golgi complex increased considerably, concurrently with increasing glycoprotein synthesis (Geuze and Slot, '76). During repopulation of the cells with mucous granules, luminal vesicles appeared close to the cell membrane between exocytotic pits. We suggest that the luminal vesicles originate by pinching off from microvilli and apical rims of cytoplasm overlying the mucous granules. Refilling of the glands was slow and took more than one week.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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