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Biomedical subjects

A Raz

Publications and source records attributed to A Raz.

At least 253 records · Page 14Linked to original sources

Differential effects of lipids on the osmotic fragility of lysosomes.

The effect of a wide range of concentrations of oleic acid, oleyl alcohol and oleic acid methyl ester on lysosomal stability has been studied under both hypotonic and isoosmotic medium conditions. Both oleic acid and oleyl alcohol exhibited a biphasic interaction pattern with lysosomes; stabilizing at low concentrations and labilizing at high concentrations. Lysosome labilization by the ester required an initial lag period.

Acid Phosphatase↗

Selective incorporation of 14C-arachidonic acid into the phospholipids of intact tissues and subsequent metabolism to 14C-prostaglandins.

A method is described for the efficient incorporation of radioactive arachidonic acid into the lipids of rabbit hearts and kidneys. Infusion of 14C-arachidonate through perfused tissues resulted in the quantitative removel of label from the media. Analysis of the lipids from tissues labeled by this procedure revealed that the majority of the 14C-arachidonate was incorporated into phospholipids. Essentially all of the radioactivity in phosphatidylcholine was found in the 2-position. Subsequent to the 14C-arachidonate infusion, stimulation of prostaglandin biosynthesis (e.g. by bradykinin) resulted in the release of radioactive prostaglandins. This suggests that the 14C-arachidonate is incorporated in a manner such that it is available for hormone-stimulated prostaglandin biosynthesis. The method described allows both qualitative and quantitative analysis of arachidonate metabolism in intact tissues and offers significant advantages over other presently used methods.

Animals↗

Effect of hashish compounds on mouse peritoneal macrophages.

Light microscopy reveals an induction of extensive vacuolation in the macrophage after exposure to either delta 1-tetrahydrocannabinol or cannabidiol. Numerous small vacuoles appear in the cell periphery as early as 15 minutes after exposure (at 37degrees C.) to either of the compounds in 20 per cent newborn calf serum-Dulbecco's modified Eagle medium. The small lucent vacuoles coaleasce and yield enormous vacuoles which dominate the the cytoplasm. At approximately 3 hours, many of the vacuoles seem to burst with a concomitant expulsion of cell interior. The effect of hashish compounds on macrophages is essentially irreversible; exposure for 15 minutes to 10(-5) m of delta 1-THC or cannabidiol and a thorough wash in 20 per cent serum-medium, suffices to trigger the sequence of vacuolation and total cell death in the culture. Two major processes involving early reorganization of cellular membranes have been observed using electron microscopy. One relates to the formation of numerous autophagic vacuoles full of organelles, the other relates to the appearance of cytoplasmic inclusions representing extensive destruction of intracellular constituents. Both types of cytoplasmic change have been observed in alveolar macrophages of hashish smokers. Thus, the conditions in the in vitro studies are similar to conditions in people exposed to hashish smoke.

Animals↗