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Biomedical subjects

H Sakurai

Publications and source records attributed to H Sakurai.

At least 505 records · Page 28Linked to original sources
PubMed1988

Thiol exchange reactions involving selenotrisulfides.

The occurrence of in vitro thiol exchange reactions involving selenotrisulfides has been documented by HPLC analyses of reaction solutions. Asymmetric selenotrisulfide (RSSeSR') (R,R' = penicillamine, cysteine, glutathione) was formed by the reactions between (i) a mixture of thiols and selenite, (ii) thiol (R'SH) and symmetric selenotrisulfide (RSSeSR), and (iii) symmetric selenotrisulfides (RSSeSR and R'SSeSR'). Further reaction of an asymmetric selenotrisulfide with thiol (R'SH) produced another symmetric selenotrisulfide (R'SSeSR'). These thiol exchange reactions may offer significant information to elucidate intake and metabolism of selenium in vivo.

Chromatography, High Pressure Liquid↗
PubMed1988

Reevaluation of urinary excretion of coproporphyrins in lead-exposed workers.

Urinary concentrations of coproporphyrin I and III (CP I and III) were determined by high-performance liquid chromatography in 131 male workers exposed to lead, and the relationships between lead exposure and urinary coproporphyrins were reevaluated. CP I had a statistically significant correlation with lead in the blood (Pb-B), but it was not useful as an indicator of the effect of lead on heme metabolism. On the other hand, CP III had a good correlation with Pb-B and markedly increased when Pb-B levels exceeded 40 to 50 micrograms/100 ml. Both sensitivity and specificity were more than 80% when the health-based Pb-B limit and the screening level of CP III were fixed at 50 micrograms/100 ml and 50 micrograms/g creatinine, respectively. In conclusion, measurement of CP III is sufficiently sensitive and specific enough in practice for the early detection of health effects due to lead exposure in the same way as the measurement of delta-aminolevulinic acid in urine.

Adult↗
PubMed1988

Unilateral hemispheric cerebral changes similar to Creutzfeldt-Jakob disease in a case of hemiconvulsion.

A 77-year-old man suffered intermittent hemiconvulsions of unknown etiology on the left side for a period of about 5 weeks. At the autopsy, there was marked neuronal loss, severe proliferation of astrocytes and spongiform changes in the right cerebral cortex. The cerebral white matter showed loosening with astroglial proliferation in areas on the same side. These neuropathological changes were slight or absent in the left cerebral hemisphere. Histopathological changes were similar to those seen in unilateral Creutzfeldt-Jakob disease (CJD). Although unilateral CJD can not be ruled out, these unilateral hemispheric changes might be induced by intermittent hemiconvulsions.

Aged↗
PubMed1988

Immunoreactive prorenin and its profragment peptide are present in human juxtaglomerular cells.

Although prorenin appears to be activated through the cleavage of its prosegment in the juxtaglomerular cells, the presence of prosegment peptide has never been demonstrated. We therefore studied prorenin in juxtaglomerular tumour cells, both by immunohistochemistry and by radio-immunoassay. Synthetic peptide covering the 14-carboxyterminal sequence of human renin prosegment was used to prepare both antibody and radiolabelled tracer. Intense immunostaining of prorenin was demonstrated in the tumour cells. By gel filtration, however, immunoreactive prorenin was shown to consist of two major components. The first peak, located at the elution position of activatable inactive renin, was regarded as prorenin. The other peak was located at an elution position with a smaller molecular weight, which was assumed to represent the profragment. These results suggest that both prosegment peptide and prorenin are present in the juxtaglomerular cells.

Adult↗
PubMed1987

EPR characterization of vanadyl (IV) species in blood cells of ascidians.

EPR spectra due to vanadyl species of blood cells of Ascidia ahodori collected from different places in Japan (Ushimado and Asamushi) were measured. The EPR spectral pattern as well as their EPR parameters for these two species were found to be different from each other. EPR analysis correlating g parallel and A parallel indicated that vanadyl ion in the animals from Ushimado was in a much stronger ligand field than those from Asamushi. Vanadyl species in the Ushimado animals was comparable to the stable complexes such as the vanadyl-ATP complex prepared at pH 12.

Animals↗
PubMed1987

Effects of taurocholic acid/HCl alone or after pretreatment with geranylgeranylacetone on phospholipid metabolism in rat gastric mucosa.

Changes in phospholipid metabolism in gastric mucosa caused by instillation of taurocholic acid (TCA)/HCl (80 mM/300 mM) into the stomach of rats and the effects of pretreatment with an antiulcer agent, geranylgeranylacetone (GGA), were studied after intravenous injection of radioisotope-labeled precursors. The instillation of TCA/HCl rapidly reduced the incorporation of labeled fatty acids and glycerol into phosphatidylcholine and phosphatidylethanolamine, indicating the inhibition of de novo synthesis of phospholipids. These changes were restored by 120-150 min after the TCA/HCl treatment. Pretreatment with GGA enhanced the incorporation of precursors into phosphatidylcholine immediately after the instillation of TCA/HCl. Experiments in which the mucosal lipids were labeled with fatty acids prior to the instillation of TCA/HCl showed that the degradation of cellular lipids and release of the products into the gastric lumen were induced by TCA/HCl and that these changes were not prevented by GGA. Since GGA almost completely inhibited the gastric lesions induced by TCA/HCl, the enhancement of synthesis of mucosal phosphatidylcholine induced by GGA may be involved in the prevention of gastric damage. The incorporation of labeled fatty acids into free fatty acid fraction and diacylglycerol was increased quickly by the TCA/HCl treatment, suggesting early damage to the blood vessels of the gastric mucosa; these changes were inhibited significantly by GGA.

Animals↗
PubMed1987

Occurrence of vanadium ion in serum albumins.

Vanadium was shown to be a contaminant in Sigma-grade serum albumins, fraction V. The levels of vanadium detected by neutron activation analysis were: bovine 16.7, ovine 10.0, rabbit 9.1, porcine 3.9, and human 0.19 micrograms/g protein. According to the ESR spectra, the vanadate form (+5 oxidation state) was strongly suggested as a chemical form present in albumins. Dialysis against a chelating agent was quite effective for removal of the metal ion.

Animals↗
PubMed1987

Effects of ethanol alone or after pretreatment with 20% ethanol on phospholipid metabolism in rat gastric mucosa.

Changes in phospholipid metabolism in gastric mucosa caused by instillation of absolute ethanol (a cell-damaging agent) into the stomach of rats and the effects of pretreatment with 20% ethanol (a mild irritant) were investigated by using radioisotope-labeled fatty acids and glycerol. The labeled precursors were incorporated mainly into phosphatidylcholine and triacylglycerol, and also to lesser extents into phosphatidylethanolamine and phosphatidylinositol + phosphatidylserine. The instillation of absolute ethanol reduced the incorporation of fatty acids and glycerol into phospholipids within 15 min, indicating the inhibition by ethanol of de novo synthesis of phospholipids. Pretreatment with 20% ethanol caused the incorporation of fatty acids into phospholipids to be maintained after absolute ethanol instillation. These results suggest that the pretreatment with 20% ethanol may protect the cellular synthetic activity of phospholipids against damage by absolute ethanol. The incorporation of fatty acids into the free fatty acid fraction, monoacylglycerol and diacylglycerol was increased by absolute ethanol instillation, suggesting damage to the blood vessels of the gastric mucosa, and these changes were inhibited to some extent by the pretreatment with 20% ethanol.

Animals↗