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Biomedical subjects

H Oka

Publications and source records attributed to H Oka.

At least 541 records · Page 30Linked to original sources

Alkaline phosphatase isoenzymes in intestinal metaplasia and carcinoma of rat stomach induced by N-methyl-N'-nitro-N-nitrosoguanidine.

Intestinal metaplasia and carcinoma of the stomach were produced in Wistar strain rats by oral administration of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Alkaline phosphatase (AlP) isoenzymes of tissues from intestinal metaplastic mucosa and carcinoma of the stomach were studied. The ALP activity from all carcinoma tissues was several times higher than that of the surrounding gastric mucosa, and two of the tissues has over 100 times higher activity. An AlP zymogram from carcinoma tissues of the stomach showed one broad active band on 5% polyacrylamide-gel disc electrophoresis. This band was separated into 2 sharp active bands after treatment with neuraminidase: A-band (Rf = 19%) and B-band (Rf = 32%). From the enzymological and immunological study, B-band had properties similar to those of AlP isoenzyme from the intestinal metaplastic mucosa of the stomach, as well as intestinal AlP isoenzyme, while A-band had different ones. Anm AlP zymogram from glandular mucosa of the stomach showed 2 types of active band (A and B band) after treatment with neuraminidase, which were identical with those appearing in carcinoma tissues. The properties of AlP isoenzyme from the intestinal metaplastic mucosa of rat stomach induced by MNNG were similar to those of humans, and the carcinoma tissues of rat stomach were suspected of producing high amounts of AlP, especially the intestinal-type AlP isoenzyme.

Alkaline Phosphatase↗

The parieto-rubro-olivary pathway in the cat.

Stimulation of the parietal association cortex as well as the frontal motor cortex elicited clearly extracellular unitary activities or field potentials in the ipsilateral inferior olive in the cat. The parietal-induced responses came out generally at a longer and more variable latency than the frontal-induced ones. This suggested the existence of an indirect pathway from the parietal association cortex to the inferior olive. The recording sites for the parietal-induced responses were located not only in the dorsal lamella but also in the ventral lamella of the principal olive and in the medial accessory olive. Such olivary sites were exclusively in the rostral half of the inferior olive, and these areas in the olive were considered to give projection fibres predominantly to the hemispherical parts of the cerebe-lar cortex (neocerebellum). Small neuronal cells were labelled with horseradish peroxidase (HRP) homolaterally in the midbrain tegmentum, after HRP was injected through recording glass microelectrodes into the inferior olive where only the parietal-induced responses were evidently recorded. These small cells were distributed in the rostral one-third of the red nucleus and/or around the adjacent midbrain reticular formation close to the lateral border of the red nucleus. In referring to recent anatomical and physiological data, such small neurones labelled with HRP could be identified as the parvocellular red nucleus neurones. The present results indicate the existence of the parieto-rubro-olivary pathway system in the cat and suggest, in association with our previous studies, that the parvocellular red nucleus neurones participate in control of highly co-ordinated posture and movement predominantly through the neocerebellum.

Animals↗

Common projection of the motor cortex to the caudate nucleus and the cerebellum.

1. Stimulation of the caudate nucleus (Cd) was found to evoke early mossy fibre (MF) and late climbing fibre (CF) responses in fairly wide areas of the cerebellar cortex in cats. Points capable of eliciting the cerebellar responses were situated exclusively in the head portion of the nucleus. These responses showed a close resemblance to those induced by stimulation of the medial part of the anterior sigmoid gyrus (ASG) both in their contours and in their distributions. 2. There was a remarkable interaction between the Cd- and the medial ASG-induced field potentials in the pontine nuclei. When conditioned by the Cd stimulation at significantly short time intervals, the field potentials evoked by the medial ASG stimulation were more remarkably suppressed than those by the lateral ASG stimulation. 3. Field potentials or extracellular unitary activities in the inferior olive elicited by the Cd stimulation were closely related to those evoked by the medial ASG stimulation both in their responsiveness and in their topographical localizations. 4. When the cortical motor area had been ablated 10--14 days previously, the Cd stimulation elicited no responses in the cerebellar cortex. 5. From these findings, it was indicated that the Cd receives collaterals of the cortico-pontine and/or the cortico-olivary axons that originated almost exclusively from the neurones in the medial ASG (area 6). This suggested the existence of a common innervation of the basal ganglia and the cerebellar systems by the premotor area of the cerebral cortex.

Animals↗

Isolation of 4.5-dihydroxyisophthalic acid an inhibitor of brain glutamate decarboxylase, produced by a Streptomyces species.

A potent inhibitor of brain glutamate decarboxylase (L-glutamate 1-carboxy-lyase, EC 4.1.1.15) was isolated from cultures of a Streptomyces species, and its structure was found to be 4,5-dihydroxyisophthalic acid. The metabolite inhibited beef brain glutamate decarboxylase 50% at a concentration of 0.12 microgram/ml (0.61 micron). The kinetic analysis indicated that 4,5-dihydroxyisophthalic acid was a competitive inhibitor having a Ki value of 0.18 micron.

Animals↗

Familial lecithin: cholesterol acyltransferase deficiency complicated with unconjugated hyperbilirubinemia and peripheral neuropathy. The first reported cases in the Far East.

Three Japanese patients with lecithin: cholesterol acyltransferase (LCAT) deficiency, the offspring of a consanguineous marriage, are described. In addition to the characteristic clinical and laboratory findings of the disease, our patients had hitherto unreported manifestations, namely unconjugated hyperbilirubinemia, peripheral neuropathy and marked hypocholesterolemia. Although the mechanism of the unconjugated hyperbilirubinemia is not clear, the role of impaired hepatic bilirubin uridine-diphosphate-glucuronyl transferase activity combined with another unknown factor(s) was postulated. Non-random assortment was observed between LCAT deficiency and haptoglobin types, as previously reported. The discovery of Japanese patients with LCAT deficiency indicates that the distribution of this hereditary metabolic disorder is not confined to the Western hemisphere.

Adult↗

Acute hypertensive cerebellar hemorrhage with signs of lower brainstem compression.

A case of acute hypertensive cerebellar hemorrhage is reported. The patient was comatose on admission and successfully survived following evacuation of the hematoma. Surgically treated similar cases are reviewed in the literature. It is suggested that prompt diagnosis, immediate removal of the hematoma, prevention of rebleeding, and careful management of pre- and intra-operative anoxia may result in better results with this highly lethal condition.

Acute Disease↗

Traumatic spreading depression syndrome. Review of a particular type of head injury in 37 patients.

From 1476 hospital admissions with head injury, 37 patients were selected on the basis of distinctive clinical features which appeared to share a single and benign aetiology. In head injuries of this type, transient neurological disorders resulted from trivial or rather mild head injuries. These disorders, which included headache, nausea and vomiting, pallor, somnolence, irritability and restlessness, stupor, hemiparesis and aphasia, appeared after a lucid interval which was usually less than two hours; then the patient either recovered, or went on to develop convulsive attacks. Recovery without convulsions was usual in children and adolescents; convulsions occurred both in infants and younger children. The symptoms were not attributable to cerebral compression but were probably due to a self-limiting cortical phenomenon. It appears that convulsive attacks occurring within a few hours of this type of head injury may not be significant as precursors of post-traumatic epilepsy. It is suggested that there is a close relation between the convulsive attacks and the non-convulsive symptoms seen in this type of injury and that both are based on a common process which has the characteristics of the spreading depression of Leão. This type of head injury should be classified as a distinct clinical entity, in which no surgical treatment is required and the prognosis is good.

Adolescent↗