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Biomedical subjects

S Hashimoto

Publications and source records attributed to S Hashimoto.

At least 1,369 records · Page 76Linked to original sources

Smooth microsomes. a trap for cholesteryl ester formed in hepatic microsomes.

Acyl-CoA:cholesterol acyltransferase was found predominantly (85%) in RNA-rich microsomes, the rest being in RNA-poor and smooth microsomes. However, the esterified cholesterol concentration of smooth microsomes was 2-fold greater than that of RNA-rich microsomes, suggesting the possibility of an interaction between RNA-rich and smooth microsomes. The distribution of cholesteryl ester between microsome subfractions was examined after incubation of a mixture of RNA-rich and smooth microsomes with [1-14C]palmitoyl-CoA. Based upon specific acyl-CoA:cholesterol acyltransferase activities of the individual fractions, only 31 +/- 3% of the total cholesteryl ester radioactivity should have been found in the smooth component. However, the smooth microsomes contained 54 +/- 3% (p < 0.01) of the radioactive cholesteryl esters. The entrapment of radioactive cholesteryl ester in the smooth microsomes could not be accounted for by passive transfer of cholesteryl ester from RNA-rich microsomes to smooth microsomes. It is proposed that cholesterol in the smooth microsomal membranes may have been esterified by acyl-CoA:cholesterol acyltrasferase located on the surface of RNA-rich microsomes with the resulting cholesteryl ester retained in the smooth microsomes. This hypothesis was strengthened by the observation that acyl-CoA:cholesterol acyl-transferase was located on the cytoplasmic surface of the RNA-rich microsomal vesicle.

Acyltransferases↗

Premovement slow cortical potentials and required muscle force in self-paced hand movements in the monkey.

Surface negative--deep positive, slowly increasing potentials prior to self-paced hand movements were recorded in the contralateral premotor, motor and somatosensory cortices, with chronically implanted electrodes. Such premovement slow potentials in the 3 cortical areas changed their magnitudes with the required muscle force in the hand movement, and the potentials in the different cortices appeared to differ slightly in the manner of change. These results may suggest that the EPSPs in the superficial parts of apical dendrites of cortical pyramidal neurons principally via certain thalamo-cortical projections are induced prior to movements in the cortices so as to adjust the required force on anticipation, and that the premotor, motor and somatosensory cortices play some different functional roles in preparatory processes for the movement performance.

Animals↗