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Biomedical subjects

A Nishimura

Publications and source records attributed to A Nishimura.

At least 289 records · Page 16Linked to original sources
PubMedDate not supplied

Neural retinal contribution to the slow negative potential of the canine electroretinogram.

To establish the normal waveform of the electrical responses from canine eyes, electroretinograms and the light peak were recorded in hybrid and beagle dogs under general anesthesia and artificial ventilation. The neural retinal and retinal pigment epithelial components were pharmacologically isolated by intravitreal glutamate injection and systemic sodium iodate administration, respectively. The a- and b-waves elicited by either flash or rectangular stimuli, the oscillatory potentials elicited by flash stimuli and the light peak elicited either by a single maintained illumination or by repetitive stimuli were almost identical with those of other vertebrates thus far studied. In contrast, in response to rectangular (several-second duration) stimuli, the c-wave was usually absent and was replaced by a slow cornea-negative potential that had a time course similar to that of the c-wave in other species. This slow negative potential was elicited at such low stimulus intensities that the a-wave was absent, was deepened by an intravenous administration of sodium iodate, was not affected by an intravitreal injection of sodium glutamate and was shallowed during the light peak. These results suggest that the slow negative potential that replaces the c-wave consists of large slow PIII, small retinal pigment epithelial c-wave and negligible contribution from the late photoreceptor potential and the dc component of the PII.

Action Potentials↗
PubMedDate not supplied

Effects of ACTH treatment on cerebral phosphorus metabolites in infants with the West syndrome.

Concentrations of phosphorus metabolites in brains of 4 infants with the West syndrome were measured by 31P MRS before and during ACTH treatment. Although intracellular pH, phosphocreatine/ATP ratio and phosphocreatine/inorganic phosphate ratio in the patients were similar to those in the controls and did not change after the ACTH treatment, phosphomonoesters/phosphodiesters ratio in the patients always decreased with ACTH treatment. These results indicate that ACTH may accelerate the maturation of phospholipids metabolism in infant brains, and the observed change may relate to the efficacy of ACTH treatment against the West syndrome.

Adrenocorticotropic Hormone↗