Biomedical subjects

M Zabel

Publications and source records attributed to M Zabel.

At least 163 records · Page 9Linked to original sources

PubMed1988

Immunocytochemical studies on parafollicular cells of various mammals.

Using specific antisera, calcitonin, calcitonin gene-related peptide (CGRP), somatostatin as well as neuron-specific enolase, chromogranin, secretory peptide I and calbindin (vitamin D-dependent calcium-binding protein) were looked for in parafollicular cells of rats, Syrian hamsters, Mongolian gerbils, mice, guinea pigs, rabbits and pigs. Calcitonin and CGRP were most invariably present in various species. Somatostatin was absent in mice and Mongolian gerbils and present in variable amounts in the remaining species. Neuron-specific enolase could not be detected in rabbits, while in the pigs and the Mongolian gerbils it could be demonstrated only in some parafollicular cells. Calbindin was present exclusively in parafollicular cells of guinea pigs. Chromogranin and secretory protein-I were present only in some animal species.

Animals↗

PubMed1988

Localization of calcitonin and calcitonin gene-related peptide mRNAs in rat parafollicular cells by hybridocytochemistry.

By use of appropriate fragments of CT DNA or a CGRP DNA and SP6 polymerase system, we produced anti-sense RNA probes labeled with biotinylated 11-UTP. The labeling and specificity of the RNA probes were confirmed using dot-blot hybridization. By use of hybridocytochemistry, CT mRNA and CGRP mRNA were localized in all parafollicular cells in control and dihydrotachysterin-pre-treated rats. We concluded that all parafollicular cells simultaneously produce both CT mRNA and CGRP mRNA, either under control conditions or after stimulation by dihydrotachysterin-induced hypercalcemia.

Animals↗

PubMed1987

S-100 protein and neuron-specific enolase in parathyroid glands and C-cells of the thyroid.

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 immunoperoxidase 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.

Animals↗

PubMed1987

Studies on localization of calcitonin gene-related peptide (CGRP) in the thyroid-parathyroid complex.

Calcitonin gene-related peptide (CGRP) was localized by an immunocytochemical technique in the thyroid-parathyroid complexes of rat, guinea pig, rabbit, and in normal human thyroids and parathyroids. Human medullary carcinomas and parathyroid adenomas were also studied. In man and all animal species examined CGRP was present in the parafollicular cell, however, in guinea pigs only in small amounts. Except in rabbits, presence of CGRP was demonstrated in nerves of the thyroid and parathyroid capsule as well as in the nerve fibers of the capsular blood vessels. In the thyroid of guinea pigs CGRP was also noted in nerve fibers and in blood vessel walls between follicles. CGRP was also present in the parathyroid glands of rat and man, in nerve fibers localized between parathyroid cells. In rabbit the parafollicular cells between parathyroid cells also expressed CGRP immunoreactivity. No CGRP was noted in the parathyroids of the guinea pig. The proximity of parathyroid cells and CGRP containing tissue structures suggests a role for CGRP in the modulation of parathyroid hormone secretion. The importance of these regulatory mechanisms appear to be different in individual species.

Animals↗

PubMed1987

Sex differences in adrenocortical structure and function. XXV. Quantitative analysis of ACTH-immunoreactive cells in the anterior pituitary of gonadectomized and gonadal hormone replaced male and female rats.

Coupled immunocytochemical and stereologic studies of ACTH-immunoreactive cells were performed on anterior pituitaries of control male and female rats and on gonadectomized and testosterone or estradiol replaced animals. The average area and average volume of studied cells as well as their number were similar in anterior pituitary glands of control male and female rats. Orchiectomy increased average area of ACTH-immunoreactive cells, an effect reversed by testosterone while neither ovariectomy nor estradiol replacement had an effect on the area of studied cells. Average volume of these cells was similar in all experimental groups studied. Orchiectomy lowered the total number of ACTH-immunoreactive cells in the gland, an effect reversed by testosterone. Also ovariectomy lowered their number while after estradiol they were more numerous, even in comparison with control females. There is no significant correlation between the size and total number of ACTH-immunoreactive cells of the rat anterior pituitary gland and the size of the adrenal gland in both, male and female control, gonadectomized and testosterone or estradiol replaced rats.

Adrenocorticotropic Hormone↗

PubMed1987

Studies on hypothalamo-pituitary corticoliberin system. IV. Quantitative changes in ACTH-immunoreactive anterior pituitary cells evoked by long-term intraventricular CRF administration and adrenalectomy.

The aim of the study was to investigate, by coupled immunocytochemical and stereologic methods, the effects of long-term intraventricular administration of ovine CRF (oCRF) on ACTH-immunoreactive cells of the rat anterior pituitary and to compare this effect with that of adrenalectomy. CRF-treated rats received 100 ng of oCRF daily for 8 days while control rats were administered with bovine serum albumin (BSA). After BSA administration number of ACTH-immunoreactive cells/mm2 was greater than in intact rats and CRF lowered their number, however, they were still more numerous than in intact rats. Neither average area nor average volume of studied cells were changed in control and CRF-treated animals if compared with intact ones. The total number of ACTH-immunoreactive cells was higher in the glands of BSA and CRF-treated rats than in intact animals. On the other hand, 60 h after bilateral adrenalectomy a marked increase in both, average area and average volume of ACTH-immunoreactive cells was found. The different response of rat corticotropes to intraventricular CRF administration and adrenalectomy may depend on the presence of operating negative corticosterone feedback in animals with adrenal glands intact. Moreover, the present study revealed the lack of correlation between the average area and average volume of ACTH-immunoreactive cells and the weight of the adrenal gland.

Adrenal Glands↗

PubMed1987

Immunocytochemical studies on thyroid parafollicular cells in postnatal development of the rat.

Studies were performed on Wistar strain rats aged 1-720 days. Immunocytochemical reactions were used to detect calcitonin, somatostatin, calcitonin gene-related peptide (CGRP), cholecystokinin, serotonin, neuron-specific enolase (NSE), secretory protein-I, chromogranin and Ca-binding protein. In the parafollicular cells of the rat, the presence of calcitonin, somatostatin, CGRP, NSE and secretory protein-I could be demonstrated. The number of parafollicular cells increased with the age of animals, and the increase was particularly pronounced in the early postnatal period and after the first year of age. The number of somatostatin-immunoreactive cells decreased after birth and increased again after the first year of age. The number of calcitonin-immunoreactive cells increased in the early postnatal period independently of the increase in parafollicular cell number, forming frequently tumor-like outgrowths in 2-year-old animals. A small proportion of these outgrowths contained no calcitonin even if they did contain somatostatin, CGRP and NSE immunoreactivity. Evident changes in immunoreactivity in the first days after birth may reflect the sudden change in environment and may be associated with growth and differentiation. In any period of life, CGRP- and NSE-immunoreactive cells have constituted the most numerous groups and, therefore, the respective antigens seem to represent the most suitable markers of parafollicular cells in the rat.

Aging↗

PubMed1986

Ultrastructural localization of calcitonin and somatostatin in C cells of rabbit thyroid.

C cells of rabbit thyroid exhibit significant differences in morphology, namely a variable nuclear structure and differences in size and osmophility of secretory granules. An examination of serial sections of these cells was made, using the immunocytochemical PAP or protein A-gold procedures. All C cells, irrespective of their morphology, were found to store both calcitonin and somatostatin in all secretory granules. The physiological role of somatostatin in calcitonin secretion by C cells is discussed.

Animals↗

PubMed1986

Immunocytochemical study of the distribution of S-100 protein in the parathyroid gland of rats and guinea pigs.

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 beta 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 pig. 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.

Animals↗

PubMed1986

Fluorinated psychopharmacological agents: noninvasive observation by fluorine-19 nuclear magnetic resonance.

Fluorinated psychopharmacological agents were measured with fluorine-19 nuclear magnetic resonance spectroscopy in the brain of intact rats that had been treated with fluphenazine. These in vivo experiments were compared to in vitro measurements of fluphenazine-treated rats. A high-field shift was observed in both in vivo and in vitro measurements. On the basis of the in vitro measurements, fluphenazine concentration in the brains of treated rats was estimated. Our observations demonstrate the feasibility of this technique for determining fluorinated neuroleptics in live mammals.

Animals↗

PubMed1985

Studies on in vitro effect of serotonin on calcitonin secretion by rat thyroid C cells.

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.

5-Hydroxytryptophan↗

PubMed1985

Ultrastructural immunocytochemical localization of neuron-specific enolase in parafollicular cells of the rat thyroid.

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.

Animals↗

PubMed1985

Application of avidin-biotinized peroxidase (ABC) method for immunocytochemical localization of corticotropin-releasing factor (CRF) in rat hypothalamus.

Studies on immunocytochemical localization of corticotropin-releasing factor (CRF) were performed in the rat hypothalamus using avidin-biotinized peroxidase (ABC) and PAP techniques. In intact and control animals CRF-immunoreactive nerve fibers were observed within outer layer of median eminence. In the adrenalectomized animals, CRF was also demonstrated in perikarya of neurocytes and in their projections in paraventricular nucleus of the hypothalamus. In both immunocytochemical techniques identical localization of CRF was obtained. However, reaction intensity was greater with the ABC technique than with the PAP one. In bilateral adrenalectomized animals, a greater number of CRF-immunoreactive neural fibers were observed in the median eminence than in control rats and rats subjected to sham operation.

Adrenalectomy↗

PubMed1984

[Focal epithelial hyperplasia (Heck disease). Contribution on its viral origin].

Demonstration of human papilloma virus DNA (HPV-DNA) in the lesions of focal epithelial hyperplasia in an 11-year-old Turkish girl provides further proof of its viral cause. In this case characterization of HPV-DNA showed a reaction with that of type 13 and 18. This previously undescribed variant is probably the expression of a new HPV type.

Child↗

PubMed1984

[Ultrastructural findings in Arndt-Gottron's scleromyxedema].

The ultrastructure of a skin biopsy taken from a 64-year-old patient with clinically typical scleromyxedema has been studied. Histologically, the disease is characterized by dermal depositions of acid mucopolysaccharides, as well as an increased number of fibroblasts and tissue mast cells. Electron microscopically, the collagen microfibrils exhibited irregularities of their shapes and widths. In addition, the elastic fibres were unevenly contrasted with small defective areas of the matrix, and there was loss of fibrils. We also encountered a substantial number of highly active "dendritic" fibroblasts that frequently contained phagolysomal cytoplasmic inclusions. Probably these cells are responsible for the increased deposition of newly formed collagen fibres and elastic material. Furthermore, peculiar variants of fibroblasts are described, the cytoplasms of which were replete with heterolysosomal and autolysosomal inclusions. Finally, the tissue mast cells showed unusually large specific granules, so that these cells may also take part in the pathological process.

Collagen↗

PubMed1984

[Histo- and pathogenesis of necrobiosis lipoidica (diabeticorum)].

50 necrobiosis lipoidica cases which were observed in the last twelve years at the Dept. of Dermatology of the University of Essen were examined. Our studies showed that local metabolic and vascular disturbances play an important factor in the histo- and pathogenesis of the necrobiosis lipoidica (diabeticorum).

Adolescent↗

PubMed1984

Ultrastructural localization of calcitonin, somatostatin and serotonin in parafollicular cells of rat thyroid.

Three hormones were demonstrated in ultrathin sections of the rat thyroid using immunocytochemical methods with either a PAP complex or a protein A-gold complex as the label. In control rats, calcitonin was found to be present in all parafollicular cells and somatostatin in occasional cells. In rats pretreated with 5-hydroxytryptophan, serotonin was detected in all parafollicular cells as well. In serial ultrathin sections, the three hormones were seen to be localized in the same secretory granules.

5-Hydroxytryptophan↗

PubMed1984

Parafollicular cells of the rat thyroid gland after treatment with vitamin D.

Ultrastructural studies on rat thyroid demonstrated two types of secretory granules in parafollicular cells. In control animals were significantly more frequent strong osmophilic granules of approximately 130 nm in diameter than weak osmophilic granules of approximately 200 nm in diameter. Number and ratio of granules of the two types varied greatly in parafollicular cells. Administration of vitamin D3 induced a depletion of strong osmophilic granule number while the larger, weak osmophilic secretory granules continued to be stored. Immunocytochemical tests detected calcitonin in the small, strong osmophilic granules and showed that calcitonin content decreased after vitamin D3 administration. The obtained results suggest that the smaller, strong osmophilic granules contain calcitonin only, while the larger, weak osmophilic ones may contain somatostatin only.

Animals↗