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Biomedical subjects

S Yamaguchi

Publications and source records attributed to S Yamaguchi.

At least 1,027 records · Page 57Linked to original sources
PubMed1984

Hook-associated proteins essential for flagellar filament formation in Salmonella typhimurium.

The hooks of the flagella of Salmonella typhimurium were purified by a newly developed method, using a flaL mutant without a filament, and the hook components were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. As a result, we detected three protein species in addition to hook protein. We call these three proteins hook-associated proteins (HAPs). Their molecular weights were 59,000 for HAP1, 53,000 for HAP2, and 31,000 for HAP3. The HAP1/hook protein/HAP3/HAP2 molar ratio, calculated from their relative amounts and their molecular weights, was 1:10:1.1:0.53. The compositions of HAPs were analyzed in the hooks from the other filamentless mutants which were defective in H1 H2, flaV, flaU, or flaW. Hooks from the H1 H2 mutant had the same HAP composition as hooks from the flaL mutant. Hooks from the flaV mutants contained HAP1 and HAP3. Hooks from the flaU mutants contained HAP1. Hooks from the flaW mutants contained a very small amount of HAP3. From these results, the process of hook morphogenesis and the genes responsible for each step were postulated. Electron micrographs of hooks from the filamentless mutants showed that hooks which contained all three HAPs had a sharp clawlike tip, whereas hooks lacking any HAP had a flat tip. Electron micrographs of hooks treated with antibody against the hook protein showed that each claw-shaped end was not covered with antibody. These results strongly suggest that all three HAPs or at least some of them are located at the claw-shaped end and play an essential role in filament formation.

Bacterial Proteins↗
PubMed1984

[A case of advanced seminomatous germ cell tumor cured with PVB combination chemotherapy].

A case of stage IIB seminomatous tumor treated with the combination chemotherapy regimen of cis-platinum, vinblastin and bleomycin is presented. The patient was a 42-year-old man who was admitted to our hospital with the chief complaint of the right intrascrotal mass and edema in right lower extremity. Right radical orchiectomy was immediately performed under the diagnosis of testicular tumor. Histological diagnosis was pure seminoma. Paraaortic bulky metastasis and right hydronephrosis were found in the abdominal CT-scan. PVB therapy for initial treatment was started. After four courses of this therapy, retroperitoneal lymphadenectomy was performed. Because no live tumor cells were found histologically in any of the dissected material, complete response was considered to have been achieved by PVB therapy. Considering the poor survival and high relapse rate of advanced seminomatous tumor treated with radiotherapy, this PVB therapy should be the initial treatment for this disease.

Adult↗
PubMed1984

Danazol suppression of gonadal estradiol-17 beta secretion--report of two sibling cases with a complete form of testicular feminization on gonadal ultrastructure and endocrine status.

It has been established that the pathogenesis of a complete form of testicular feminization syndrome (TFM) is due to end-organ unresponsiveness to androgens. In the present study, two sibling cases with TFM have been reported with special reference to the effect of danazol (a derivative of 17 alpha-ethynyltestosterone) on gonadal estradiol-17 beta (E2) secretion in vivo and in vitro. Both patients showed hypergonadotropic-hypergonadism with good response to LH-RH. In one case, peripheral blood E2 levels seemed to fall independently of gonadotropins during danazol administration in vivo. Administrations of danazol to the culture media also inhibited E2 secretion from the cultured monolayered cells of the testes. These results suggest a direct inhibitory effect of danazol on gonadal E2 secretion. However, the feedback mechanisms of hypothalamic-pituitary units to E2 were preserved in both cases. Spermatogeneses were almost undetectable as in immature embryonal testes when using either light or electron microscopies, though spermatogonia were differentiated from Sertoli cells by these techniques. Finally, plasma T and E2 levels in both patients were considerably lower after gonadectomy.

Adult↗
PubMed1984

Effects of naftidrofuryl on the time course of the regional cerebral blood flow in acute ischemic stroke.

The effects of naftidrofuryl (LS-121), which is known as an activator of the cerebral glucose metabolism in addition to acting as a cerebral vasodilator on the regional cerebral blood flow (rCBF), were investigated in acute and subacute ischemic stroke patients. Six acute patients and 5 subacute patients were treated with 100-200 mg/day of naftidrofuryl for 7-14 days, and the rCBF was measured before and after the treatment by the 133Xe inhalation method. The hemispheric rCBF was significantly increased by 24% for the acute stage and 22% for the subacute stage in the affected side, compared with the stage-matched control group. Naftidrofuryl may accelerate the recovery of the rCBF of the affected hemisphere even in the acute stage.

Adult↗
PubMed1983

Pituitary folliculo-stellate cells immunostained with S-100 protein antiserum in postnatal, castrated and thyroidectomized rats.

Pituitary folliculo-stellate cells and associated cells were studied immunohistochemically throughout the life of male and female rats. The marginal layer cells of the pars distalis and intermedia as well as the folliculo-stellate cells were immunostained with anti-S 100 protein serum. The immunostained folliculo-stellate cells in one section were identified as themselves by their ultrastructural properties on the adjacent section. Corticotrophs, thyrotrophs and prolactin cells, characterized by the stellate shape, were not immunostained with anti-S 100 protein serum. Reactivity for S-100 protein appeared on postnatal Day 6 in the marginal layer cells of the pars intermedia, and appeared on Day 10 in those cells of the pars distalis. No immunostained folliculo-stellate cells appeared before Day 6, but a few of them appeared on Day 10. Thereafter they increased in number, having more intense immunostaining with advancing age. In castrated rats, the immunostained folliculo-stellate cells appeared quite numerously, with branched cytoplasmic processes surrounding the gonadotrophs. In the thyroidectomized rats, however, folliculo-stellate cells lacked ramified cytoplasmic processes, and their topographic affinity for thyrotrophs was negligible.

Age Factors↗
PubMed1983

Diaminobenzidine peroxidase in rat brain.

Peroxidase has several roles in each organ. In neural tissue, it is considered from pathological examination to be related to the aging process. To study biochemically the presence of peroxidase, diaminobenzidine was used as the hydrogen donor and the enzyme was partially purified from rat brain and characterized. Diaminobenzidine peroxidase was purified 670-fold from the original homogenate. The presence of p-phenylenediamine and guaiacol peroxidase was not detected in either the crude homogenate or the partially purified fraction. The possible presence of isozyme(s) in peroxidase was implied and this may be related to the physiologic differences in organs.

Animals↗
PubMed1983

Hypoxic-ischemic cerebral necrosis in midgestational sheep fetuses: physiopathologic correlations.

Thirty-eight midgestational sheep fetuses were exposed 120 min to marked hypoxia. The brains in eight that reduced their mean arterial blood pressure to less than 30 mm Hg were markedly damaged. In these same fetuses the serum lactic acid concentrations were elevated during exposure to hypoxia to excessively high values (greater than 15 mM) and remained elevated for a prolonged period during recovery. Twenty-one fetuses exposed to the same magnitude of hypoxia that maintained their blood pressure unchanged showed less marked elevations of serum lactate concentrations and remained brain-intact. Greater quantities of pentobarbital administered to the ewes during hypoxia seemed to protect the brain from hypoxia and this effect was dose-dependent. Exposure of midgestational sheep fetuses to marked hypoxia associated with reductions in cerebral blood flow due to decreased blood pressure and impaired cerebral autoregulation caused major focal cerebral necrosis.

Animals↗
PubMed1983

Excretion of flagellin by a short-flagella mutant of Salmonella typhimurium.

A nonmotile mutant of Salmonella typhimurium, SJW1254, has very short flagella (less than 0.1 micron long) due to a mutation in the structural gene of flagellin (H2). When ammonium sulfate was added to the culture medium of SJW1254 grown to the late-log phase, a large amount of protein precipitated. Gel electrophoresis and immunodiffusion showed that more than 90% (wt/wt) of the precipitated protein was flagellin. The mutant flagellin appeared to be excreted in the monomeric form, in an amount comparable to the amount in the flagellar filaments of wildtype bacteria. No such precipitate was obtained from the medium of wild-type bacteria. The mutant flagellin had the same apparent molecular weight (55,000) and isoelectric point (5.3) as the wild-type flagellin, but differed in mobility in polyacrylamide gel electrophoresis under nondenaturing conditions. Moreover, the mutant flagellin did not polymerize in vitro under various conditions in which wild-type flagellin polymerized. These results suggested that the mutant bacteria excreted flagellin because the flagellin polymerized poorly and therefore could not be trapped at the tip of the flagellar filament. This short-flagella mutant should be useful for studying the mechanism of flagellin transport.

Bacterial Proteins↗