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Biomedical subjects

M Sano

Publications and source records attributed to M Sano.

At least 523 records · Page 29Linked to original sources

Inhibitory effect of intravenous lysine infusion on urea cycle metabolism.

Intravenous infusion of 0.5 mmol/kg L-lysine monohydrochloride was performed in six normal volunteer subjects aged 10-14 years to study the inhibitory effect of lysine on urea cycle metabolism. The lysine infusion resulted in a significant increase in plasma levels of arginine and ornithine, and in urinary homocitrulline, putrescine, and orotic acid, accompanied by a significant increase in blood ammonia. There was little change in plasma urea and citrulline. The increase in plasma arginine appears to reflect an inhibited arginase activity although the plasma urea level did not change. The increased homocitrulline excretion suggests that ornithine conversion to citrulline via ornithine transcarbamylase (OTC) was inhibited. The simultaneous increase in plasma ornithine and urinary putrescine may reflect an inhibition of mitochondrial ornithine transport. In addition to the direct ammoniagenic property of lysine, impaired ornithine conversion to citrulline resulting from the inhibition of both OTC activity and mitochondrial ornithine uptake by lysine may be responsible for the increase in blood ammonia and urinary orotic acid. Despite the retarded citrulline formation, a promoted efflux of citrulline from mitochondria may have kept the plasma citrulline level unchanged.

Adolescent↗

Increased urinary excretion of putrescine in hyperargininaemia.

A 4-year-old boy with hyperargininaemia had an increased urinary excretion of putrescine which was exaggerated with oral ornithine supplementation. It seems unlikely that putrescine was overproduced within the gut, because a loading with a single oral dose of ornithine showed that the intestinal ornithine absorption in the patient was normal. An acceleration of extramitochondrial ornithine metabolism due to impaired mitochondrial ornithine uptake may have caused the hyperexcretion of putrescine.

Adolescent↗

Induction of S-100b (beta beta) protein in human teratocarcinoma cells.

Human teratocarcinoma NT2/D1 cells undergo differentiation into a variety of cell types, including neurons, treated with retinoic acid. In the present study, the concentrations of alpha S-100 and beta S-100 proteins (alpha and beta subunits of S-100 proteins), and three subunits (alpha, beta and gamma) of enolase in NT2/D1 cells were measured using the sensitive enzyme immunoassay method. The concentration of beta S-100 was markedly increased in the cells after treatment with retinoic acid, whereas the concentration of alpha S-100 was undetectably low, indicating that the S-100b (beta beta) protein was induced by retinoic acid. On the other hand, the concentrations of the three forms of enolase isozymes did not change in the same culture. The induction of S-100b protein was not observed in the NT2/D1 cells after treatment with forskolin, dibutyryl cyclic AMP or cholera toxin. The indirect double-labeled immunofluorescence, using antibodies specific to beta S-100 and monoclonal antibodies specific to neurofilaments, revealed that both the S-100b protein and the neurofilaments were induced in the same subpopulation of cells which underwent neuronal differentiation.

Antibodies, Monoclonal↗

Small-cell carcinoma of the esophagus: a case treated by chemotherapy.

A patient with small-cell carcinoma of the esophagus treated with cyclophosphamide and vincristine is described. Within 2 months after the beginning of therapy, two coexisting tumors had disappeared and the main primary lesion and metastases in the liver and lymph nodes were markedly reduced in size. The patient relapsed 5 months after the start of therapy and died with widespread metastases. Autopsy revealed that the patient was in partial remission.

Aged↗

Predictors of disease course in patients with probable Alzheimer's disease.

The presence of extrapyramidal signs or psychosis may indicate greater disability in patients with probable Alzheimer's disease. We evaluated the ability of these signs, noted at a patient's first visit, to predict one of two specific clinical endpoints: (1) a preselected score on the modified Mini-Mental State examination (cognitive endpoint), and (2) a preselected score on the Blessed Dementia Rating Scale (functional endpoint). Sixty-five patients were followed either until they reached the endpoints or to the end of the study period. Survivorship curves were drawn to predict the distribution of time to onset of an endpoint in patients with and without the clinical signs. Time to reach the cognitive endpoint was shorter for patients with extrapyramidal signs or psychosis compared with those without these signs and symptoms. These clinical signs did not predict the functional endpoint. We conclude that extrapyramidal signs and psychosis may be useful predictors of intellectual decline in Alzheimer's disease.

Activities of Daily Living↗

Clinical and biochemical correlates of bradyphrenia in Parkinson's disease.

Bradyphrenia is considered the mental equivalent of bradykinesia in Parkinson's disease. Patients are described as inattentive and "slow thinking," but not demented. We compared the performance of three groups: parkinsonians age-matched controls, and mildly impaired patients with probable Alzheimer's disease in tests of general intellect, memory reaction time, and in a continuous performance task measuring attention and vigilance. Metabolites of the major biogenic amine in CSF were also measured. The parkinsonians formed two distinct groups. In one, intellectual function and CSF measures were similar to that of controls. The other group of parkinsonians had significantly more omission errors and fewer correct response on the continuous performance task than did controls or patients with Alzheimer's disease. We considered this second group to have bradyphrenia. Their performance on measures of general intellectual and memory function was similar to that of the patients with Alzheimer's disease. CSF-MHPG, the major metabolite of norepinephrine, correlated with the continuous performance task and reaction time in all parkinsonians, and those with bradyphrenia had the highest CSF-MHPG levels. Our data suggest that bradyphrenia is an impairment of attention and vigilance, unique to Parkinson's disease, that may be associated with dementia and with an alteration in norepinephrine metabolism.

Aged↗

Motility and drug susceptibility of Angiostrongylus cantonensis developing from gamma-irradiated first-stage larvae.

The effects of neuropharmacological agents on the motility of irradiated and non-irradiated Angiostrongylus cantonensis adult females were studied. GABA induced complete paralysis in non-irradiated and 5,000 R-irradiated worms, but caused only slight paralysis on 10,000 R-irradiated worms. The paralytic effect of GABA was antagonised by picrotoxin. The reason for low susceptibility of heavily irradiated worms to GABA is not known. There was no difference in susceptibility of non-irradiated and irradiated worms to other neuropharmacological agents including eserine, phenylephrine and dibenamine.

Angiostrongylus↗