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  • 1
    Call number: ZSP-166(220)
    In: Berichte aus dem MARUM und dem Fachbereich Geowissenschaften der Universität Bremen
    Type of Medium: Series available for loan
    Pages: 136 S.
    Series Statement: Berichte aus dem Fachbereich Geowissenschaften der Universität Bremen 220
    Classification: D.3.
    Location: Lower compact magazine
    Branch Library: GFZ Library
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  • 2
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After castration of 90-day-old male and female rats, changes appear in the renal proximal tubule. A distinction can be made between early changes (up to 10th postoperative day) and later changes (20th–30th postoperative day). Between the 3rd and 5th day after castration the kidney of the females shows an increase in free estrogen receptors (biochemical studies) which are localized in the pars contorta of the proximal tubule (autoradiographic studies), while the male kidney shows a marked increase in urinary protein excretion up to the 10th day after castration. Proximal tubule changes detectable histochemically and electron microscopically do not appear until day 20 or 30 after castration. The results of castration are similar in segments S1 and S2. By days 20 and 30 after castration there is a decrease in the activity of lysosomal enzymes (acid phosphatase, acid β-galactosidase). Electron microscopy shows a conspicuous decrease in the number of giant lysosomes (mainly in females) and apical vacuoles (mainly in males). A marked increase in the number of lysosomes is found in the S3 segment; females always have more lysosomes than males. The number of peroxisomes is also greatly increased; they appear circular in the females but can assume bizarre shapes in the males. Lipid droplets appear in the basal region of the tubule cell of segments S2 and S3 in the males. The sex differences are preserved in all segments even after castration and become even more pronounced in the S3 segment.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Abstract The study was aimed at a morphological demonstration of calcitonin (CT) gene expression in cultured TT cells, or, more specifically, hybridocytochemical detection of CT mRNA and calcitonin gene-related peptide (CGRP) mRNA and ultrastructural localization of the two hormones. The TT cells originated from medullary carcinoma of human thyroid gland. Ultrastructural studies of TT cells demonstrated a well-developed rough endoplasmic reticulum, large Golgi apparatus and low number of secretory granules. Hybridocytochemical studies showed the presence of mRNAs for CT and CGRP in all TT cells. At the ultrastructural level, double immunolabelling demonstrated that the two hormones were always expressed together in the same secretory granules. Our results provide a significant addition to the biochemical studies performed up to now and indicate that all TT cells produce both mRNAs and both hormones in parallel.
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  • 4
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using unlabeled antibodies and peroxidase-anti-peroxidase complexes, calcitonin was localized at the ultrastructural level in rat thyroid C cells. Calcitonin was present mainly in secretory granules of the cells. A less intense positive reaction was noted in the cytoplasm surrounding the secretory granules.
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  • 5
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using pre- and post-embedding procedures, neuron-specific enolase and calcitonin were localized in rat thyroid parafollicular cells by light and electron microscopy. Peroxidase-antiperoxidase (PAP), biotin-avidin (ABC) and protein A — colloidal gold techniques were used. In paraffin sections neuron-specific enolase was demonstrated in all calcitonin-storing parafollicular cells in rats aging 1 to 180 days. The post-embedding procedure failed to detect neuron-specific enolase in ultrathin sections, but the enzyme could be demonstrated using a preembedding procedure. Neuron-specific enolase was localized exclusively within the cytosol of parafollicular cells, while calcitonin was localized within secretory granules applying either post- or pre-embedding incubation techniques.
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  • 6
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thyroid glands of young rats were incubated for 3 h in Eagle's solution supplemented with 5-hydroxy-l-tryptophan (5-HTP) or with serotonin. Following control incubations or incubations with serotonin, no serotonin could be demonstrated in C cells using immunocytochemical techniques. However, serotonin was demonstrated in the secretory granules of all C cells following incubation with 5-HTP. The secretory function of C cells was evaluated by ultrastructural and immunocytochemical studies, and by calcitonin radioimmunoassays of the incubation medium. Following incubation with 5-HTP, the secretory function of the majority of C cells was inhibited, and calcitonin levels in the media were decreased. Incubation with serotonin produced an increased secretory function of C cells and higher calcitonin levels in the media. The results indicate that serotonin and its direct precursor, 5-HTP, affect calcitonin secretion by rat thyroid C cells by distinct mechanisms.
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  • 7
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The distribution of S-100 protein in the parathyroid cells of normal and hypercalcaemic rats and guinea pigs was investigated. Previous studies had shown that the applied antibodies detect only the β subunit of S-100 protein. S-100 protein was found in all parathyroid cells of rats aged between 1 and 720 days. In adult guinea pigs, S-100 protein was detectable in only a small proportion of parathyroid cells. The level of S-100 protein in individual cells exhibited considerable variation, particularly in guinea pigs. Hypercalcaemia did not affect the distribution of S-100 protein in the parathyroid cells of either rats or guinea pigs. In both species, the presence of small groups of parathyroid cells in the central fragments of thyroid lobes was often noted.
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  • 8
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Normal parathyroid glands and parafollicular cells (C-cells) of man, rat and rabbit, and also human parathyroid adenomas and medullary carcinomas were investigated for the presence of S-100 protein and neuron-specific enolase (NSE). For determination of the proteins immuno-peroxidase methods were applied, i.e., the PAP method and the avidin-biotin system. The antisera, of polyclonal origin, were specifically directed against cow S-100 protein and rat or bovine NSE. The respective antisera are known to crossreact with S-100 protein from man, rat, and rabbit, as well as with NSE from man and rat. Surprisingly, the test for S-100 protein was found to be strongly positive in the parathyroid glands of rat and rabbit and was focally positive in normal and adenomatous human parathyroid glands, but completely negative in C-cells and medullary carcinoma cells. NSE was present in C-cells of rat and man, and in medullary carcinoma cells, but was absent in normal and adenomatous parathyroid cells. The results support data that indicate that both parathyroid cells and C-cells are derived from elements of the neural crest, but undergo different maturation processes during embryological development.
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  • 9
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Hypercalcemia was induced in rats by the administration of A.T.10. We then determined the levels of total and ionized calcium and calcitonin in the serum, as well as performed ultrastructural observations and histochemical investigations of the calcitonin and neuron-specific enolase immunoreactivities in the stimulated parafollicular cells. The main aim of the study was to apply histochemical procedures to determine the immunoreactions of calcitonin gene-related peptide (CGRP), somatostatin and secretory protein-I in stimulated parafollicular cells. Immunoreactions of CGRP and calcitonin decreased strikingly in A.T.10-treated animals, whereas no visible changes were noted in somatostatin immunoreactivity. In the case of secretory protein-I, an insignificant increase of its immunoreactivity was observed in the treated animals. The cytophysiological significance of these results is discussed.
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  • 10
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Using anti-human calcitonin serum and a protein !-gold technique, calcitonin was localized at the ultrastructural level in control and calcium gluconate-stimulated thyroid C cells of the rat. In control rats calcitonin was dedected within a majority of the secretory granules while in experimental animals it was demonstrated also within prosecretory granules present in Golgi apparatus.
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