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Biomedical subjects

H Ohyama

Publications and source records attributed to H Ohyama.

At least 109 records · Page 6Linked to original sources
PubMed1983

Purification and characterization of amino-acid N-choloyltransferase from human liver.

Amino-acid N-choloyltransferase was purified from human liver. The procedure resulted in about 100-fold enriched activity and glycine- and taurine-dependent activities co-purified and did not separate to any extent in any of the steps. The final enzyme preparation had an apparent molecular mass of 100 kDa by gel filtration, 118 kDa by sucrose density gradient centrifugation and was composed of two identical subunits which had a molecular mass of 52 kDa, as judged by dodecyl sulfate polyacrylamide disc gel electrophoresis. The glycine- and taurine-dependent activities showed optima at pH 7.2 and pH 6.5, respectively. Apparent Km values of purified enzyme were 3.2 and 0.6mM for glycine and taurine, respectively. The Km value for choloyl-CoA was 50 microM for the glycine-dependent activity and 87 microM for the taurine-dependent activity. Bile acid derivatives and cholesterol had an inhibitory effect on both glycine- and taurine-dependent activity in vitro; on the other hand, the reaction was stimulated by the addition of glutathione, EDTA and L-cysteine. Amino acid substrate specificity was restricted to glycine, taurine, beta-alanine and D-alpha-alanine. As well as choloyl-CoA, its deoxy derivatives were also good substrates for the enzyme.

Acyltransferases↗
PubMed1983

Prevention of interphase death in rat thymocytes by bisulfite.

The effect of sodium bisulfite, a specific inhibitor of chromatin proteolysis, on radiation damage in rat thymocytes in vitro was examined. Rat thymocytes irradiated with 1 kR X rays in vitro were incubated at 37 degrees C with 10 mM glucose for 4 to 6 hr. During that time development of interphase death as judged by erythrosin B uptake, release of low molecular weight DNA (free DNA), and reduction in cell size was measured. Sodium bisulfite added to the cells at the beginning of incubation exerted a marked preventive effect on radiation damage. The effect was enhanced with increasing concentration of bisulfite from 0.25 to 2 mM. The effect of bisulfite was reversible; i.e., removal of bisulfite from the cells resulted in the reappearance of the radiation damage.

Animals↗
PubMed1983

Appearance of cell fragments in thymus after a whole-body X-irradiation of rat.

Changes in surface architecture and three dimensional structure of rat thymus cortex were examined by scanning electron microscopy (SEM) after a whole-body X-irradiation. The samples of thymus prepared from rats 4 to 8 hr after a 400 R irradiation were observed by SEM. Normal thymocytes, having tiny microvilli and shallow ridges, decreased in number after irradiation, with a corresponding increase in radiation damaged round shaped cells with occasional protrusions and pores. With time after irradiation, smaller spherical fragments of cells having smooth or porous surfaces increased in number.

Animals↗
PubMed1982

[Centro-median thalamotomy for central pain following stroke --its effectiveness and limits].

Centro-median thalamotomy was performed on 18 patients with central pain caused by cerebrovascular disease. Fourteen were males and four were females. Clinical diagnoses were thalamic pain in 17 cases including cheiro-orale syndrome in one case and phantom limb pain in one case. CT scans were performed on six recent cases. Four cases had a small low density sera in the thalamus. The other two cases had no remarkable findings. The target was 7.5-11.0 nm posterior to the middle point of the intercommissural line, 1.0 mm below-2.0 mm above that line and 5.5-10.0 mm from the midline. Unilateral lesion was made on 15 cases. Postoperatively, five cases had almost completely relief of pain and four cases had partial improvement. The duration of pain relief was, however, less than two months in four cases, and between three and seven months in four cases. One case had a pain free period for seven months. But, then, severe dysesthesia appeared. Six cases had no pain relief by unilateral lesion. Two cases had no pain relief by bilateral lesions. In the remaining case, unilateral lesion was effective for six months. Then lesion of opposite side was made, but the result was unsatisfactory. The durations from the onset of apoplectic attack to the occurrence of pain were between four months and three years in ten effective cases, and within three months in six among eight failed cases. Many surgical and medical treatments have been attempted for central pain. However, ideal method is still not appeared. Centro-median thalamotomy was effective for 56% of the patients with central pain. But in most of the cases, the duration of pain relief is about a half year at the longest. And may be, this is the limit of effectiveness of centro-median thalamotomy for central pain.

Adult↗
PubMed1981

[Trigeminal neuralgia and hemifacial spasm caused by the compression of tortuous vertebro-basilar system--a case report (author's transl)].

A 63-year-old man was admitted to our clinic on August 14, 1980 with the chief compliant of left-sided intermittent facial pain. He had been suffering from twitching of the left facial muscles since 1972. During two years before admission, severe pain of the left face, starting in the left upper jaw and radiating to the left periorbital region, occurred intermittently. The pain aggravated by eating, talking and face-washing, gradually worsened and he became unable to take meals. On admission, he was alert. No sensory disturbance was seen. Muscle twitching was seen in the left orbicularis oculi, orbicularis oris and sometimes in the platysma. Mild facial palsy was recognized on the left side and other cranial nerves were intact. Computed tomogram with contrast enhancement revealed shift of the basilar artery to the left side. Markedly enlarged and tortuous vertebrobasilar system kinking at the left cerebello-pontine angle, was seen on the left vertebral angiogram. This tortuous vertebrobasilar system was presumed to be the cause of the trigeminal neuralgia and hemifacial spasm. The neuralgia disappeared after a controlled thermocoagulation of the left Gesserian ganglion, and the frequency of hemifacial spasm was reduced too. He was discharged with mild hemifacial spasm. The combination of trigeminal neuralgia and hemifacial spasm caused by direct compression of tortuous vertebro-basilar system on the nerve roots is rare. A case was reported and the literature were reviewed.

Basilar Artery↗
PubMed1981

Disappearance of microvilli accompanying radiation-induced interphase death of rat thymocytes.

Thymocytes are radiosensitive and show interphase death (immediate death) after irradiation. The present investigation was undertaken to characterize by scanning electron microscopy the shape of thymocytes irradiated in vitro with 1 kR X-rays and determine the cell surface changes that accompany the development of interphase death. Exposing the cells to X-rays caused disappearance of the microvilli, usually observed with viable cells. Association of dead thymocytes with porous surface without any digitations was confirmed by the examination of enriched dead cell populations prepared by centrifuging the cell suspension in Percoll density gradient.

Animals↗