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At least 307 records · Page 17Linked to original sources
PubMed1989

Adrenal chromaffin cells as transplants in animal models of Parkinson's disease.

The field of neural transplantation has moved rapidly forward in the last decade. Initially, fetal cells were used as implants to investigate their potential to ameliorate deficits in animal models of Parkinson's disease. However, because of the moral and legal problems associated with the use of fetal tissues in humans, alternative sources of donor tissue were sought which possessed the structural and functional characteristics needed to improve motor function in Parkinsonian patients. To date, one of the most promising tissues being investigated is the adrenal medulla, whose chromaffin cells possess an inherent plasticity of form and function. Transplanted chromaffin cells currently are being studied by a variety of approaches, including electron microscopy, in mouse, rat, and primate models of Parkinson's disease. An overview of the role of the chromaffin cell in this exciting and clinically important arena is briefly reviewed, with an emphasis on the fine structure of implanted chromaffin cells.

Adrenal Medulla↗
PubMed1985

Light- and electron-microscopic demonstration of enkephalin-like immunoreactivity in paraganglia of the human urinary bladder.

The distribution of enkephalin-like immunoreactivity in paraganglia of the urinary bladder of adult humans was studied by use of immuno-electron microscopy. All paraganglionic cells were positively stained. Enkephalin-like immunoreactivity was located in chromaffin granules. Chromaffin cells in the paraganglia showed only few degenerative features, suggesting undisturbed function of the cells.

Chromaffin System↗
PubMed1995

Separation of nanoliter samples of biological amines by a comprehensive two-dimensional microcolumn liquid chromatography system.

A two-dimensional liquid chromatography system based on the combination of a charge separation mechanism, provided by anion exchange chromatography, with a hydrophobic separation mechanism, provided by reversed phase chromatography, is presented. A 90 cm long anion exchange microcolumn is coupled to a 3 cm long reversed phase microcolumn. Both microcolumns are interfaced by two electronically controlled valves. Effluent from the anion exchange microcolumn is collected in a sample loop and then concentrated onto the head of the reversed phase microcolumn. Analyte peaks consisting of tagged amines elute from the second column and are detected by laser-induced fluorescence. The entire operation is controlled by a personal computer. The resolving power of this system is demonstrated with a two-dimensional chromatogram of the peptides obtained from a tryptic digest of porcine thyroglobulin. The sensitivity of the system is demonstrated with a two-dimensional chromatogram of the contents of a single bovine chromaffin cell.

Amines↗
PubMed1984

The ultrastructure of hypertrophied paraganglia in aged rats.

The catecholamine-storing cells in the paraganglia of old rats showed structural characteristics common to adrenomedullary and paraganglionic cells of young animals. No sign of degeneration was found. Lipofuscin pigment was observed in most cells. The paraganglia were innervated and well supplied by fenestrated sinusoidal capillaries. Their fine structure suggests active endocrine function. An increase in the total bulk of the paraganglia in old rats suggests that they have a physiological role in senescence.

Aging↗
PubMed1984

Enteric-type adenocarcinoma of the nasal cavity. An electron microscopic and immunocytochemical study.

A primary adenocarcinoma of the nasal cavity with light microscopic, electron microscopic, and immunocytochemical features of an enteric-type carcinoma is presented. The carcinoma contained a variety of dense-core granules similar to those seen in enterochromaffin cells of different functional types. Some granules demonstrated an immunoreactivity with serotonin, cholecystokinin, gastrin, somatostatin and leu-enkephalin antibodies. It is suggested that the endocrine cells in the neoplasm belong to the non-neuroectodermal paraneurone system.

Adenocarcinoma↗
PubMed1989

Development and plasticity of adrenal chromaffin cells: cues based on in vitro studies.

Neural crest derived precursors of the sympathoadrenal cell lineage give rise to two major cell types that differ in a number of morphological, ultrastructural, and biochemical characteristics: principal sympathetic neurons and chromaffin cells of the adrenal medulla. The present article reviews experimental studies performed on cultured adrenal medullary cells and designed to unravel the nature of epigenetic signals governing the developmental choice between the endocrine chromaffin and the neuronal sympathetic phenotype. Emphasis is placed on the role of glucocorticoids in initiation, development, and maintenance of the endocrine chromaffin phenotype and apparently antagonistic influences exerted by nerve growth factor (NGF) in vitro, resulting in the acquisition of neuronal properties by differentiated chromaffin cells. Experimental data from in vitro studies are compatible with the following conclusions. Glucocorticoids represent the decisive signal for the initial induction of endocrine differentiation. Moreover, high steroid hormone concentrations, as present in the adrenal medulla, are a prerequisite for the maturation of chromaffin cells. Even in a differentiated state, the endocrine phenotype is unstable in the absence of glucocorticoids, and the cells seem to reenter the neuronal developmental pathway. Under these conditions, cellular survival and differentiation into sympathetic neurons become NGF-dependent, as in normal sympathetic development. Thus, the effects of NGF survival, neurite outgrowth, and transmitter synthesis of cultured chromaffin cells probably do not reflect the induction of a specific phenotype, but they may be interpreted as a general neurotrophic support observable with other responsive cell types.

Adrenal Medulla↗
PubMed1976

Histochemical light microscopic study of catecholamine containing paraganglia in the human pelvis.

Histological and histochemical techniques have been employed to determine the structure and autonomic innervation of paraganglia located in the human pelvis. In foetal and early postnatal tissues, paraganglia formed rounded cellular masses which were frequently in company with the autonomic nerves and ganglia of the urinary bladder and other pelvic viscera. The constituent cells contained only small amounts of cholinesterase and were unrelated to enzyme positive autonomic nerves; acetylcholinesterase containing nerves were occasionally observed in the capsule and the fibrous septa of the pelvic paraganglia. In early postnatal specimens, pelvic paraganglia frequently contained single or multiple "pacinian-like" corpuscles, each possessing a central region which was rich in both acetyl and pseudocholinesterase. These structures were rarely observed within autonomic ganglia and were absent 4 1/2 years post partum. By means of a histochemical technique, pelvic paraganglia were found to contain catecholamine which was attributed to the presence of relatively large quantities of noradrenaline. These observations have been discussed with particular reference to the results of other studies on the autonomic innervation of paraganglia.

Child, Preschool↗