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Biomedical subjects

M Goldberg

Publications and source records attributed to M Goldberg.

At least 559 records · Page 31Linked to original sources
PubMed1984

[Demonstration of lipids by imidazole-buffered osmium tetroxide in the odontoblasts and cells of the enamel organ in the rat incisor].

Tissue post-fixation with imidazole buffered osmium tetroxide allows localization of lipids rich in unsaturated fatty acids (Angermüller and Fahimi, 1982). In odontoblasts, a positive reaction is observed in mitochondria, in membranous structures and in vesicles containing an osmiophilic and amorphous material. In odontoblastic processes, tubulo-vesicular structures and electron-dense coated vesicles seemed to be engaged in endocytosis and transfer processes towards lysosomial structures of the cell body. In the enamel organ, lipidic structures are observed in the stellate reticulum and the stratum intermedium. The plasma membrane of secretory ameloblasts as well as the content of some lysosomial structures are well contrasted. However the distal membranes of the Tomes processes showed weakly stained portions alternating with electron dense segments. Extracellular lipidic globules, sometimes associated with plasma membranes were also seen. These observations demonstrated the alternating weak and strong staining reactions in unsaturated fatty acids of plasma membrane areas of the cell processes, which contrasts with the continuous staining of the plasma membrane of the cell bodies. These observations could be related to functional differences.

Animals↗
PubMed1984

Autologous mixed lymphocyte reaction in man. XIV. Deficiency of the autologous mixed lymphocyte reaction in acquired immune deficiency syndrome (AIDS) and AIDS related complex (ARC). In vitro effect of purified interleukin-1 and interleukin-2.

Peripheral blood mononuclear cells from male homosexuals with acquired immune deficiency syndrome (AIDS) and with AIDS related complex (ARC) were examined for the autologous mixed lymphocyte reaction (AMLR) between responder T and irradiated autologous non-T cells and in vitro influence of purified human interleukin-1 (IL-1) and -2 (IL-2) on the AMLR. The AMLR was significantly (P less than 0.001) deficient in both ARC and AIDS; the deficiency of the AMLR was of the similar magnitude in two groups when compared to asymptomatic homosexuals and healthy heterosexuals. In vitro addition of IL-2 enhanced the AMLR to the baseline levels of control subjects in most patients in ARC group (P less than 0.01) and in four of 15 patients in AIDS group (P less than 0.01). Addition of IL-1 to IL-2 containing cultures resulted in no further increase in the AMLR response over those with IL-2 alone. This study demonstrates deficiency of the AMLR in patients with ARC and AIDS that is corrected by purified IL-2 in the majority of cases with ARC but only a subset of patients with AIDS. The significance of these findings is discussed.

Acquired Immunodeficiency Syndrome↗
PubMed1984

Volvulus of the splenic flexure of the colon.

Volvulus of the splenic flexure is rare. Only 20 cases have been reported. Two additional patients are presented. Both had previous abdominal operations and were correctly diagnosed by barium enema. Resection and anastomosis in the two stages was performed in one patient and unwinding with fixation of the bowel in the other. The literature is reviewed and the pathogenesis discussed.

Adult↗
PubMed1984

The distribution of filipin-cholesterol complexes in secretory ameloblasts of rat incisor.

The number of filipin-sterol complexes, visualised as 25-35 nm protuberances on freeze-fracture replicas of secretory ameloblasts of rat incisor, was small on the plasma membrane and nil on internal membranes of the cell body. Distal infoldings and vesicles inside Tomes process presented a higher number of protuberances. Such membrane-induced deformations were especially abundant on membrane remnants left inside the forming enamel and in holes at the dentine-enamel junction. This reflects regional variations of cholesterol or accessibility of cholesterol. Increased rigidity of membranous remnants may play a role in the induction of local defects during rat enamel formation. These observations clarify the origin of phospholipids and cholesterol detected biochemically.

Ameloblasts↗
PubMed1984

Distribution of filipin-cholesterol complexes in rat incisor odontoblasts.

Using the polyene antibiotic filipin as a probe to visualize cholesterol on freeze-fracture replicas of membranes of young odontoblasts of rat incisor, we demonstrated that cholesterol-rich domains were present in cell processes, whereas only a small number of deformations induced by cholesterol-filipin interaction was observed in cell bodies. Except for a few large vesicles, intracellular membranes did not react with filipin. The large number of intramembrane particles observed on the plasma membrane of odontoblast processes did not affect the formation of visible filipin-cholesterol complexes.

Animals↗
PubMed1984

Natriuretic and water diuretic effects of guanabenz, a central alpha-2 agonist.

I should like to preface my concluding remarks by noting that our observations are still of a preliminary nature. Guanabenz, an acute central adrenergic inhibitor produces in human subjects (previously volume expanded with saline) changes similar to those previously described in animals, namely a rise or no change in GFR, an enhancement of water diuresis, and a significant natriuresis. Within one week of the acute study and during chronic administration of guanabenz, all of these changes were reversed: GFR, the magnitude of the water diuresis and the enhanced sodium excretion had returned to the baseline pre-guanabenz levels, indicating that certain adaptive, restorative mechanism were operative. One may conclude, however, that the potential natriuretic properties of guanabenz (even during chronic administration), counter-balance the sodium retaining side effects commonly seen with other centrally acting and vasodilating antihypertensive drugs. This property, therefore, makes this agent a scientifically interesting and potentially useful therapeutic drug in the treatment of high blood pressure.

Adult↗
PubMed1983

Nuclear magnetic resonance studies of Ba1 bacterium and some model systems.

Lithium NMR relaxation times of some model systems and E. coli cells in high LiCl concentration were measured. The lithium NMR relaxation times were compared to the relaxation times in the holotolerant bacterium Ba1 (Goldberg, M., Risk, M. and Gilboa, H. (1983) Biochim. Biophys. Acta 763, 35-40). Complementary studies of the water protons NMR relaxation times were carried out. It is suggested that the lithium in the H.S. Ba1 bacterium is occulated in small pores of the cell envelope.

Chlorides↗
PubMed1983

Enhancement of desynchronized sleep signs after pontine microinjection of the muscarinic agonist bethanechol.

The question of which brainstem neuronal receptors can mediate cholinergic REM sleep induction was investigated by injecting the pure muscarinic agonist bethanechol via glass micropipettes in the pontine tegmentum of cats. The REM sleep enhancement was observed to be equally potent, equally dose-dependent and its appearance equally site-dependent as that previously observed with carbachol, a mixed muscarinic/nicotinic agonist. The results suggest that the pharmacological activation of muscarinic receptors in pontine neurons is sufficient to trigger REM sleep.

Animals↗
PubMed1983

A convenient enzyme-linked immunosorbent assay for testing whether monoclonal antibodies recognize the same antigenic site. Application to hybridomas specific for the beta 2-subunit of Escherichia coli tryptophan synthase.

Seven hybridoma clones, producing antibodies directed against the beta 2-subunit of Escherichia coli tryptophan synthase, have been obtained from mouse cells. To test whether the corresponding monoclonal antibodies recognize different epitopes on beta 2, an ELISA double antibody binding system has been developed and is reported here. The antigen is first coated onto a microtitration plate. Two monoclonal antibodies are then added either separately or simultaneously, and the amount of bound antibody is quantitatively measured by use of immunoglobulin (rabbit anti-mouse IgG) linked to beta-galactosidase. Additivity of the bound enzymatic activity is observed when the monoclonal antibodies bind to distinct epitopes. Using this test, it is shown that, of the 7 anti-beta 2 monoclonal antibodies obtained, 5 recognize the same antigenic site and the 2 others recognize a second site.

Animals↗