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Biomedical subjects

S Yokoi

Publications and source records attributed to S Yokoi.

At least 73 records · Page 4Linked to original sources
PubMed1980

Latency of plantar grasp.

Latency of plantar grasp was measured in 437 normal infants from the first day to 6 months of age with a special instrument for measurement of the latency. The latency was prolonged during the birth shock period and returned to the previous value and remained at almost the same value until 7 days, then gradually shortened during the first four months. After 5 months, the values were not reliable. Our method is simple and not only is useful for assessment of maturation of the nervous system, but also helpful for better understanding of the pathophysiology of the nervous system.

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PubMed1979

Atypical leukodystrophy with accumulations of sulfatide and mucopolysaccharide.

1. Follow-up studies of two siblings with mental retardation, progressive paraplegia and dementia were reported. 2. The brain and visceral organs of a patient (elder brother) who died recently were investigated histopathologically, electronmicroscopically and neurochemically. a. Moderate, diffuse demyelination occurred throughout the white matter of the central nervous system. b. Two abnormal materials were deposited in the white matter: one showed metachromasia containing sulfatide and another had staining characteristics of acid mucopolysaccharide histochemically. Electronmicroscopically, the former was a conglomerate of electron-dense materials of various degrees and the latter had a membrane-limited granular structure. The myocardium contained the same mucopolysaccharide material as that in the brain. c. Slight increase of sulfatide was found in the cerebral white matter. Arylsulfatase A activities were preserved in the brain as well as in the liver. Contents of hexosamine and uronic acid in the white matter were about three or five times as much as that of the controls. Electrophoresis on cellulose acetate membrane showed that acid glucopeptide was the main component of the mucopolysaccharide extracted from the brain.

Adult↗
PubMed1977

Atypical GM1 ganglioside accumulation in a case of juvenile amaurotic idiocy.

The brain and liver from a 7-year-old Japanese girl with juvenile amaurotic idiocy were examined neuropathologically and biochemically. Visceromegaly and skeletal abnormalities were absent. Nerve cells in the central nervous system were swollen and contained fine fat granules. Electronmicroscopically, there were large numbers of irregular bodies in the perikarya and these corresponded to the curvilinear and membranous cytoplasmic bodies. Lipid analysis of the brain revealed that GM1 ganglioside was increased in the parietal and occipital areas, while the frontal lobe showed a normal ganglioside pattern. N-Acetyl neuraminic acid (NANA) content in all areas was not elevated. Determinations of beta-galactosidase activity were within normal ranges. The liver had no accumulation of GM1 ganglioside and showed a normal beta-galactosidase activity. These unusual findings in GM1 gangliosidosis were discussed.

Brain↗
PubMed1975

Biochemical studies on tissues from a patient with Lafora disease.

Tissues from the cerebral cortex, liver and myocardium of a patient with Lafora disease were obtained at autopsy and were studied biochemically. 1. Glucose content in the myocardium and liver was almost nil while that in the controls was 0.66 mg/g wet weight in the former and 8.80 mg/g wet weight in the latter. Glycogen content in the cerebral cortex and myocardium was about 10 and 3 times more than in controls. 2. Polyglucosan extracted from the cerebral cortex, liver and myocardium had a longer exterior glucose chain than that in the liver of the control but a normal, alpha or beta 1,4-glucosidic linkage was observed. 3. The activities of glucose-6-phosphatase and amylo-1,6-glucosidase in the cerebral cortex, liver and myocardium were well preserved. The activities of acid maltase in the three organs mentioned above and of neutral maltase in the myocardium were elevated twice and one and half times more than the control. Phosphorylase levels in the myocardium were extremely small, while in the cerebral cortex and liver normal activities were observed. In light of these findings, glycogen metabolism in Lafora disease is discussed.

Adult↗