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Biomedical subjects

M S Amer

Publications and source records attributed to M S Amer.

33 records · Page 2Linked to original sources
PubMed1973

Cyclic adenosine monophosphate and hypertension in rats.

Aortas from spontaneously hypertensive and stress hypertensive rats contained significantly lower intracellular concentrations of cyclic adenosine monophosphate than did their respective controls. Adenylate cyclase activity was normal but was less responsive to stimulation, while phosphodiesterase activity (especially the low Michaelis-Menten constant form) was significantly elevated. Human aortas contained two forms of phosphodiesterase that were similar to those in rat aortas.

Adenylyl Cyclases↗
PubMed1968

Studies with tryptophan metabolites in vitro. Kynurenine metabolism in kidneys of mice infested with Schistosoma mansoni.

The conversion in vitro of kynurenine into kynurenic acid and anthranilic acid in both normal kidneys and those obtained from mice infested with Schistosoma mansoni was investigated. Normal mouse kidneys seem to possess an excess of functional pyridoxal phosphate over those obtained from infested mice. Kynureninase and kynurenine transaminase in the latter kidneys are more easily inhibited by deoxypyridoxal phosphate and tartar emetic, indicating low stores of active pyridoxal phosphate. The possible implication of these findings in relation to the role of the kidneys in producing abnormal patterns of tryptophan metabolism and possibly contributing to the production of bladder tumours in bilharzial patients is discussed.

Animals↗
PubMed1967

Studies with tryptophan metabolites in vitro. Kynurenine metabolism in liver homogenates of normal and Schistosoma mansoni-infested mice.

The conversion of kynurenine into kynurenic acid and anthranilic acid in both normal and Schistosoma mansoni-infested mouse liver was investigated. It was found that in the S. mansoni-infested mouse liver there is probably a deficiency of pyridoxal phosphate that resulted in an inhibition of kynurenine transaminase and a low production of kynurenic acid. Deoxypyridoxine and its phosphorylated derivative inhibited kynurenine transaminase in the normal liver in a pattern qualitatively similar to that observed with infested liver. The lowered concentration of pyridoxal phosphate in the infested liver is discussed in view of the possibility of two combined mechanisms: (a) an antimetabolite being secreted by the infesting worms or present in its eggs that partially inhibited the phosphorylation of pyridoxal, and (b) concentration of pyridoxal phosphate by the worms, resulting in a lowered concentration of the cofactor in the host tissue.

Animals↗