Biomedical subjects
Publications and source records attributed to M Shibuya.
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Cerebrospinal fluid (CSF) homovanillic acid (HVA) concentration was measured in 39 consecutive cases of hemispheric infarction, 7 cases of brainstem infarction, and in 16 controls. The CSF-HVA level was 38 +/- 15 ng/ml (mean +/- S.D.) in the control patients, 15 +/- 6 ng/ml in patients with brainstem infarcts, and 49 +/- 41 ng/ml in those with hemispheric infarcts. The CSF-HVA levels were decreased in brainstem infarct cases (p less than 0.001) and greatly scattered in patients with hemispheric infarcts (range 4--207 ng/ml) when compared to controls. The decrease of levels of CSF-HVA in brainstem infarct cases may reflect interference with the dopaminergic pathways. CSF-HVA values in hemispheric infarction could not be related to the acuteness, location, nor severity of the lesion. The broad range of CSF-HVA values may be due to the interaction of multiple, as yet unknown factors. These findings suggest that dopamine metabolism is altered in many cases with acute brain infarction.
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Based on the following genetical experiments, the cya gene in E. coli was shown to be involved in the synthesis of both cyclic AMP and cyclic GMP. First, all five independent cya-deficient mutants accumulated exceedingly low amounts of cyclic GMP. Second, the ability to form both cyclic AMP and cyclic GMP was simultaneously restored by transduction of an intact cya locus to one of the above cya-deficient mutants. Third, a spontaneous revertant from one of the above mutants regained the synthetic activity for cyclic GMP as well as for cyclic AMP. Fourth, the characteristic of a strain overproducing cyclic GMP was co-transduced with the cya locus. These results suggest that the synthesis of both cyclic GMP and cyclic AMP is mediated by the same enzyme, adenylate cyclase, Interestingly, a reciprocal effect of glucose starvation was observed on the accumulation of both cyclic nucleotides. The formation of cyclic AMP was greatly enhanced on glucose starvation, whereas that of cyclic GMP proceeded at a slower rate than in the presence of glucose. This effect was observed only in cells carrying normal cya and crp genes, but not in a cya-altered or a crp-deficient strain.
The echocardiographic features of annuloaortic ectasia were studied in 12 patients. Eleven of them exhibited skeletal and/or ophthalmic findings of Marfan's syndrome and one was considered as having forme fruste. Echocardiograms revealed not only marked dilatation of the aortic root but also unique motion of the aortic wall and aortic valve. Posterior motion of the posterior aortic wall during early to middle ejection period, i.e., "paradoxical" motion, was noted in eight cases, and premature systolic partial closure of the aortic valve was seen in all cases.
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A standard echocardiographic technique was proposed for an analysis of the intracardiac anatomy of endocardial cushion defect (ECD). It consisted of two beam directions, mitral and tricuspid, and two M-mode scans, between the mitral and tricuspid valves and between the mitral and aortic valves. Using this technique, echocardiographic studies were performed on 13 patients with ECD, including 10 patients with the incomplete form and three patients with the free-floating form. In patients with the incomplete form, an M-mode scan between the mitral and tricuspid valves showed the specific features of the interaction between the mitral valve, the interventricular septum, and the tricuspid valve, termed the "mitral-interventricular septal-tricuspid (MVT) connection." The systolic multiple echoes and the diastolic echoes of the so-called posterior leaflet of the mitral valve were constant findings in the mitral direction. The tricuspid valve, although less continuous, was recorded simultaneously with the mitral valve in the same direction. Ateriorly displacement of the anterior mitral leaflet was shown on an M-mode scan between the mitral and aortic valves, giving an echocardiographic representation of the angiocardiographic "goose-neck" sign. Evidence showing the presence of right ventricular volume overload was also found. In patients with the free-floating form, an anterior common A-V valve with a large excursion was recorded on an M-mode scan between the mitral and tricuspid valves. The valve was located posterior to the interventricular septum in the mitral direction and anterior to the septum in the tricuspid direction. There was no finding to show the interaction between the valve and the septum. The posterior common A-V valve was registered only in the mitral direction. Our technique made it possible to diagnose ECD, using a noninvasive echocardiographic method, and discriminate the free-floating form from other forms of ECD.
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Analysis has shown that the over-all death rate from renal disease for residents of New York City under 25 years of age has declined from 4.6 per 100,000 in 1950 to 2.3 per 100,000 in 1970. Nephritis and nephrosis was the major disease category accounting for this decrease in deaths. A similar trend was found for the United States as a whole. Other causes of renal disease did not manifest consistent changes in death rates. The decline in deaths from nephritis and nephrosis could not be ascribed solely to changing diagnostic habits or terminology. A possible alternative explanation is a change in the natural history of these diseases. Data of this type might be useful as an index to future trends in the mortality rate from renal diseases and as one basis for projections of potential future needs for dialysis and renal transplantation. Using 1965 data, we estimate the number of such potential candidates in New York City would have been 9 per 1,000,000 for the 5 to 14 year age group and 23 per 1,000,000 for the 15 to 24 year age group. There are significant limitations of projections based on such data. These estimates of potential candidates for chronic dialysis or renal transplantation are the first available for children in the United States.
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