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Biomedical subjects

J Cohen

Publications and source records attributed to J Cohen.

At least 1,441 records · Page 80Linked to original sources
PubMed1979

Monolayer cultures of perikarya isolated from postnatal rat cerebellum.

Viable cerebellar perikarya of mixed cell type obtained from 7--9-day-old rats were maintained in monolayer cutlure for up to 12 days. During this time extensive neurite formation and outgrowth occurred. The large majority of the cells developing in culture were tentatively identified as granule neurons. This identification was based on the large number isolated from the starting tissue, and the cells' general morphological features in culture such as perikaryal and nuclear size, the bipolar nature of neurite extension, and their migratory behaviour.

Animals↗
PubMed1979

Preparation of viable astrocytes from the developing cerebellum.

A cell fraction enriched in viable astrocytes has been prepared from the developing rat cerebellum. The isolated astrocytes were identified by indirect immunofluorescence using antiserum to glial fibrillary acidic protein (GFAP). In comparison with the low incidence (6%) of GFAP-positive cells in the unfractionated cell suspension from trypsinized cerebellar tissue, these accounted for half of the cells in the final preparation. This was achieved by treatment at 6 days of age with hydroxyurea (an inhibitor of DNA synthesis) which enriched the tissue in GFAP-positive astrocytes at day 8. At the same time, by selectively removing the heterogeneously sized replicating cells, hydroxyurea treatment allowed resolution of a fraction enriched in GFAP-positive cells using unit gravity sedimentation. The isolated astrocytes differentiated in culture producing, by 3 days in vitro, a dense network of fine GFAP-containing processes.

Animals↗
PubMed1979

Brief vs standard hospitalization: for whom?

An effort was made to determine patient characteristics that have differential prognostic significance, depending on treatment assignment to one of three treatment approaches: standard inpatient care (n = 63), brief hospitalization followed by day care (n = 61), and brief hospitalization without day care (n = 51). All were followed by outpatient care. Both demographically and clinically assessed behavioral variables were related to a number of outcome measures, including days in the community, clinical ratings, and family assessment. Generally, the standard treatment was inferior to the two brief treatments. Multiple previous admissions were particularly contraindicative for standard treatment. High overt anger score was especially contraindicative for brief hospitalization without day care and particularly indicative for brief hospitalization with day care.

Adult↗
PubMed1979

Activation of rotavirus RNA polymerase by calcium chelation.

Two types of particles were isolated during purification of rotavirus. Dense (D) particles have a density of 1.38 in CsCl and exhibit spontaneously a fully active endogenous transcriptase. Light (L) particles (density of 1.36 in CsCl) need to be treated with chelating agents to show a polymerase activity. The activation process of L particles was studied under strictly controlled monovalent, divalent, and hydrogen ion concentrations. These experiments demonstrate that i) activation is not affected by the ionic strength ii) activation occurs only at a pH higher than 7.1 iii) a low concentration of chelating agent (40 muM EDTA) is sufficient to activate the enzyme. Treatment of particles with EGTA, which chelates selectively Ca2+, leads to unmasking even in the presence of magnesium, indicating that the concentration of free calcium ions plays a major role in the activation process. Various glycosidases, detergents, and chelating agents were tested in respect to unmasking properties. Of these compound only chelating agents turned out to be efficient. Following activation, two glycopeptides were solubilized. These glycopeptides have an apparent molecular weight of 34,000 and 31,000 daltons and react with concanavalin A. The role of Ca2+ upon the stability of virus particles, and the activation of the endogenous transcriptase in vitro and in the infected cells is discussed.

Animals↗
PubMed1979

A selected review of current retinal research and study.

This paper presents a digest of 50 retinal research projects reported in one British and two American journals from July 1976 through June 1977. The articles reviewed report recent developments pertaining to effects of excessive light on retinal tissue in newborn rats, pathogenesis of cotton-wool spots, control of the blood-retinal barrier in diabetes, infections, macular diseases, variations in retinal pigment epithelium, and retinal detachment.

Adult↗
PubMed1979

Strongyloides stercoralis infection and small intestinal lymphoma.

A West Indian man who was infected with Strongyloides stercoralis developed small intestinal obstruction. Treatment with thiabendazole did not relieve the obstruction which was found at laparotomy to be due to a poorly differentiated small intestinal lymphoma. There was no blood eosinophilia or accumulation of eosinopohils in the sites of infection. There was no reaction in the skin to delayed hypersensitivity antigens and the blood T lymphocyte count and serum C3 levels were low. From these findings and a review of the literature it was concluded that the immune response in man to Strongyloides stercoralis may depend on T lymphocyte mediated reactions including granuloma formation, and mast cell and eosinophil responses in tissues. We suggest that the association of strongyloides hyperinfection and small bowel lymphoma in this patient may not have been fortuitous. The lymphoma may have led to a reduction in cellular immunity, with the subsequent development of strongyloides hyperinfection.

Adult↗
PubMed1979

Effects of verapamil, dantrolene and lanthanum on catecholamine release from rat adrenal medulla.

1. The release of catecholamines (CA) from rat adrenal incubated in vivo in Locke solution was studied. 2. Acetylcholine-induced release of CA and CA release by 56 mM KCl were inhibited by verapamil and lanthanum chloride which block calcium permeability. 3. CA secretion induced by salbutamol or by theophylline was unaffected by either verapamil or lanthanum chloride. 4. Dantrolene-sodium inhibited the CA secretion induced by theophylline but only partially reduced potassium-induced release of CA. 5. Verapamil enhanced the secretion of CA induced by salbutamol (in a calcium-free medium). 6. Tyramine-induced secretion of CA was unaffected by lanthanum chloride, verapamil or dantrolene-sodium. 7. It is suggested that cyclic adenosine 3',5'-monophosphate-mediated CA secretion (induced by theophylline or salbutamol) depends on release of calcium from intracellular stores, and that CA secretion induced by tyramine is independent of intra- or extracellular calcium.

Adrenal Medulla↗
PubMed1979

Renal tubular acidosis associated with type III glycogenosis.

Two children who presented with severe failure to thrive were found to have Type III glycogen storage disease. They both also had defects of tubular acidification, an association not previously described. The nature of the tubular lesion is characterized and the explanation and therapeutic implications are discussed.

Acidosis, Renal Tubular↗
PubMed1979

Relationship between plasma, RBC, and CSF lithium concentrations in human subjects.

Simultaneous measurement of plasma, RBC, and plasma lithium concentrations took place with 17 inpatients chronically treated with lithium, at various times after the last lithium dose. RBC lithium levels were significantly higher than CSF lithium levels. Specimens drawn 10 or more hours after the last dose showed higher RBC and CSF lithium and lower plasma lithium than specimens drawn 4 or less hours after the last lithium dose. None of the lithium measurements differentiated manic-depressives from schizophrenics or schizoaffectives. Plasma, RBC, and CSF lithium all intercorrelated highly and equally.

Adult↗