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Biomedical subjects

H Miyata

Publications and source records attributed to H Miyata.

464 records · Page 26Linked to original sources
PubMedDate not supplied

Role of polychlorinated dibenzofuran in yusho (PCB poisoning).

In the blood of 15 patients with yusho or "polychlorinated biphenyl poisoning" that occurred in 1979 in Taiwan, was found polychlorinated dibenzofurans (14 of 15) and polychlorinated quaterphenyls (15 of 15), as well as polychlorinated biphenyls (15 of 15). The mean concentration ratio of these substances was approximately 1 : 160 : 500. Based on the following evidence, we propose that polychlorinated quaterphenyls were major pathogenic substances in the development of yusho: (1) Clinical manifestations and course of yusho patients are disproportionately severe and persistent for the observed blood levels of polychlorinated biphenyls, while patients who were occupationally exposed to pure polychlorinated biphenyls take characteristically mild and benign clinical course despite polychlorinated biphenyl levels often much higher than those noted in yusho patients; (2) Polychlorinated debenzofurans show a marked tendency to accumulate in the liver, which might explain frequent presence of jaundice and other abdominal symptoms in yusho, which are, again, not observed in those with occupational polychlorinated biphenyl poisoning; (3) Toxicity of polychlorinated dibenzofurans is a hundred to ten thousand times greater than that of polychlorinated biphenyls and polychlorinated quaterphenyls in animal experiments.

Benzofurans↗
PubMedDate not supplied

Effects of chronic atenolol therapy on cardiovascular response to isometric exercise in essential hypertension.

Cardiovascular response to 2 min of isometric handgrip exercise at 50% of maximum voluntary contraction was studied echocardiographically in 10 essential hypertensives, before and during treatment with atenolol for a mean of 2 months. The patients responded with increases in heart rate, systolic and diastolic blood pressures, cardiac output and calculated triple product, no changes in stroke volume and total peripheral resistance, and decreases in ejection fraction, mean velocity of circumferential shortening and mean diastolic posterior wall velocity of the left ventricle before treatment. Chronic atenolol therapy attenuated the increases in heart rate, blood pressure and triple product, and the decreases in ejection fraction, mean velocity of circumferential shortening and mean diastolic posterior wall velocity of the left ventricle but resulted in a marked increase in total peripheral resistance. The pressure response and triple product rise in response to isometric handgrip exercise were also decreased. This suggests an obvious advantage to hypertensive patients who may, therefore, be protected from the risk of cardiovascular complications following isometric exercise.

Atenolol↗
PubMedDate not supplied

Optokinetic nystagmus after cerebellar uvulonodulectomy in squirrel monkeys.

After cerebellar uvulondulectomy in squirrel monkeys (Saimiri sciureus), a change occurred in the optokinetic nystagmus, in that there was a slow-phase eye speed decline, at the stimulus speeds above 90 degrees/sec. The difference was statistically significant when pre- and post-ablative comparisons were made. This result supports the usefulness of the optokinetic nystagmus examination to diagnose conditions which involve posterior inferior vermis of vestibulo-cerebellum. The optokinetic after-nystagmus depicted a similar decline postoperatively.

Animals↗
PubMedDate not supplied

Multiple exostoses--mental retardation (MEMR) syndrome: report of a case.

A MEMR syndrome occurred in a 9-year-old boy with cerebral atrophy and was established by computed tomography scans of the cranium. The patient had mental retardation, delayed speech development and microcephaly, and high levels of urinary dermatan sulfate and heparin sulfate, which are characteristics of this inborn error of mucopolysaccharide metabolism.

Brain↗
PubMedDate not supplied

Evidence for the involvement of NMDA receptors in vestibular compensation.

The involvement of NMDA (N-methyl-D-aspartic acid) receptors in the initial stage of the vestibular compensation was evaluated by examining the effect of MK-801 on this compensation in guinea pigs. MK-801, injected 30 min before induction of unilateral labyrinthectomy by an arsanilate, significantly (P < 0.05) reduced the maximum frequency of the spontaneous nystagmus (SN) towards both the arsanilate-applied and the intact sides. In addition, injection of arsanilate into the opposite middle ear, 60 days subsequent to induction of the unilateral labyrinthectomy, suppressed the SN towards the second injected side, but had no effect on the SN towards the first injected side. These results suggest that NMDA receptors may be linked to the initiation of the vestibular compensation.

Animals↗
PubMedDate not supplied

Lack of rearranged Tpr-met mRNA expression in human gastric cancer cell lines and gastric mucosa and carcinoma.

The met protooncogene was activated by a rearrangement involving the fusion of tpr (1q25) and met (7q21-31) gene sequence in a human osteosarcoma cell line (HOS) incubated in vitro with N-methyl-N-nitro-N-nitrosoguanidine (MNNG). We examined the expression of tpr-met mRNA by means of the reverse transcription-nested polymerase chain reaction (RT-nested PCR) in human two gastric cell lines (MKN-1 and MKN-45), T-cell acute lymphocytic leukemia cell line (MOLT-4), and in gastric tissue samples including normal mucosa, intestinal metaplasia and carcinoma from three surgical specimens. A DNA fragment of 88-bp was amplified in MKN-1 and MOLT-4, 96-bp in MKN-45 and of 58-bp in all nine tissue samples including gastric carcinomas. The amplified DNA sequences were not homologous with the rearranged tpr-met gene. Our study indicated that rearranged tpr-met mRNA is not expressed either in human gastric carcinoma cell lines or in gastric mucosa and carcinoma.

Adenocarcinoma↗