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N Sakamoto

Publications and source records attributed to N Sakamoto.

At least 379 records · Page 21Linked to original sources
PubMed1986

[Brain edema initially develops in the periphery of focal cerebral ischemia].

Ischemia causes disturbances of the ionic equilibrium, i.e., Na+ and water influx and K+ efflux. When the ischemic tissue keeps contact with cerebral blood flow, brain tissue equilibrates with systemic circulation and consequently shifts of electrolytes and water are induced. Therefore, brain edema should initiate in the peripheral area of focal cerebral ischemia. To test this hypothesis, we performed the following experiments. Focal ischemia was induced by occlusion of the right common carotid artery in gerbils and by embolization with microspheres in rats. Water and electrolyte content was determined using punched out samples and regional K+ and Ca2+ distribution was visualized by histochemical K+ staining and 45Ca-autoradiography, respectively. Cerebral blood flow and glucose metabolism were evaluated by 14C-iodoantipyrine or 18F-fluoroantipyrine and 14C-deoxyglucose autoradiographies, respectively. Two hours of ischemia in gerbils with definite hemiparesis caused K+ depletion in the ischemic area, often most pronounced in the periphery of the lesion. Water content of cerebral cortex was 79.0 +/- 0.9, 82.0 +/- 1.0, 80.7 +/- 0.9 (%; mean +/- SD) for nonischemic, periphery and center of ischemia, respectively (significantly different with each other). Na+ content was increased and K+ content was decreased most prominently in the periphery of ischemia. Exogenous Ca2+ was also accumulated in the periphery. In the embolized stroke in rats, K+ depletion and Ca2+ accumulation obviously rimmed the ischemic focus. Furthermore the infarcted area was only part of the disturbed area of acute-phase glucose metabolism. Thus water and ionic disturbances were different between in the periphery and in the center of focal cerebral ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

A role of the heavy subfraction of the floating lipids in acute alcoholic fatty liver of rats.

Two subfractions of floating lipids were studied to clarify the subcellular pathogenesis of ethanol-induced acute fatty liver in the rat. The main lipid in both the heavy and light subfraction was triglyceride, but the heavy subfraction was richer in phospholipids than the light subfraction. After ethanol-treatment of the animals, not only triglyceride but also phospholipids increased significantly in the light subfraction. The similarity of the phospholipid species in the two subfractions suggests a possible exchange of lipids between them. The heavy subfraction consisted of membrane-free lipid droplets of very low density lipoprotein (VLDL) size plus membrane-bound, vacuolated organelles; the light subfraction consisted of membrane-free lipid globules larger than 1000 nm in diameter. Occasionally adherent particles, 40 to 100 nm in diameter, were detected on the surface of the lipid globules. After ethanol treatment, the ratio of adherent particles to lipid globules increased significantly. These observations suggest that the biogenesis of acute alcoholic fatty liver in rats involves first the formation of membrane-free lipoproteins of VLDL size in the cytoplasm and subsequently their fusion to pre-existing lipid globules.

Acute Disease↗
PubMed1985

Identification of Escherichia coli by detection of hydroquinone and uracil in the urine system.

For rapid identification of Escherichia coli, changes of urinary metabolites incubated with E. coli were investigated by gas chromatography--mass spectrometry. Hydroquinone and uracil were detected and the normal urinary constituent 4-deoxythreonic acid was found to diminish in urine incubated with E. coli. Hydroquinone could not be detected in urine incubated with Klebsiella pneumoniae, Serratia marcescens or Pseudomonas aeruginosa. Although uracil was detected in normal urine, urine incubated with E. coli showed an increased uracil level. Urine incubated with K. pneumoniae, S. marcescens or P. aeruginosa evidenced no such change. A decrease of 4-deoxythreonic acid was noted in urine incubated with S. marcescens or P. aeruginosa. In 7.0 X 10(7) cells of E. coli, 0.33-2.36 micrograms of hydroquinone and 13.4-42.0 micrograms of uracil were detected after 3 h of incubation at 38 degrees C, and production was not changed after 4, 5 or 8 h of incubation. These results suggest that the detection of hydroquinone and uracil in urine is useful for rapid identification of E. coli.

Escherichia coli↗
PubMed1985

Availability of 6-hydroxynicotinic acid for rapid identification of Pseudomonas aeruginosa and Serratia marcescens.

Gas chromatography--mass spectrometry has been used to identify specific metabolites produced by Gram-negative bacteria such as Pseudomonas aeruginosa, Serratia marcescens, Klebsiella pneumoniae and Escherichia coli in a defined medium. 6-Hydroxynicotinic acid was detected in spent culture media of Pseudomonas aeruginosa and Serratia marcescens, but could not be detected in those of Klebsiella pneumoniae and Escherichia coli. The production of 6-hydroxynicotinic acid was recognized by the addition of nicotinic acid in urine with Pseudomonas aeruginosa or Serratia marcescens, but not without the addition of nicotinic acid. Among 10(5) Pseudomonas aeruginosa per 1 ml of urine (criteria for the diagnosis of urinary tract infection), 0.15 microgram of 6-hydroxynicotinic acid was detected in urine at 4 h incubation with nicotinic acid at the optimum pH of 6.9, 38 degrees C. The production of 6-hydroxynicotinic acid was proportional to the number of the bacteria and displayed a time dependency. These results suggest that the availability of 6-hydroxynicotinic acid might make for more rapid identification of bacteria than current methods.

Culture Media↗
PubMed1985

Effects of a fructose-rich diet and the aldose reductase inhibitor, ONO-2235, on the development of diabetic neuropathy in streptozotocin-treated rats.

Streptozotocin-diabetic rats were maintained on a 72% fructose diet for 4 weeks and some were treated with an aldose reductase inhibitor (either alrestatin: 0.9 g . kg-1 . day-1 or ONO-2235: 50 mg . kg-1 . day-1). Fructose feeding significantly influenced the development of impaired motor nerve conduction velocity in the diabetic rats and this effect was positively correlated with sorbitol accumulation in the sciatic nerve of diabetic rats maintained on a fructose-rich diet. Treatment with ONO-2235, a new aldose reductase inhibitor, prevented both slowing of motor nerve conduction velocity and elevation of nerve sorbitol concentration. On the other hand, erythrocyte sorbitol levels were significantly correlated to those of the sciatic nerve (r = 0.86, p less than 0.001) and the retina (r = 0.91, p less than 0.001) in these animals. Thus, our findings suggest that increased polyol pathway activity may be related to the pathogenesis of diabetic neuropathy and erythrocyte sorbitol concentrations may prove a useful indicator for the presence of diabetic complications.

Aldehyde Reductase↗
PubMed1985

Characterization of a partially purified leptospiral genus-specific protein antigen.

A leptospiral genus-specific protein antigen (GP-Ag) was partially purified from Leptospira interrogans serovar kremastos strain Kyoto and canicola strain Hond Utrecht IV, by treating the organisms with Triton X-100 followed by a purification procedure including fractionation with DEAE-cellulose column chromatography and ethanol precipitation. Genus-specificity of the antigens from kremastos Kyoto and canicola was shown by the immunodiffusion (ID) test. Complement fixation (CF) test and enzyme-linked immunosorbent assay (ELISA) using GP-Ag from kremastos Kyoto showed the genus specificity of the GP-Ag. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) of the antigens from kremastos Kyoto and canicola showed a major band with Coomassie blue stain. The band of GP-Ag from kremastos Kyoto was also shown by immunoprecipitation using the monoclonal antibody (GP-7) to GP-Ag from kremastos Kyoto. The molecular weight of the genus-specific antigen was estimated to be approximately 62 000. The genus specificity of the antigen was reduced by heating at 100 degrees C or treatment with proteolytic enzymes, but not reduced by treatment with sodium metaperiodate.

Agglutination Tests↗
PubMed1985

Detection of antibodies to leptospiral genus-specific antigen in human and animal sera by indirect hemagglutination test with a partially purified genus-specific protein antigen.

Antibodies against leptospiral genus-specific antigen were detected in the sera from clinically diagnosed human leptospirosis and suspected animal leptospirosis by indirect hemagglutination (IHA) test with a partially purified genus-specific protein antigen (GP-Ag). The reaction was positive in the infected humans and animals irrespective of the leptospiral serovars. No significant correlation was found between IHA titer against GP-Ag and microscopic agglutination (MA) titer. IHA titer did not always develop in parallel with MA titers. Sera obtained from healthy individuals were negative in both IHA and MA tests.

Animals↗
PubMed1985

Production of monoclonal antibodies against leptospiral genus-specific protein antigen and localization of the antigen by immunoelectron microscopy.

Monoclonal antibodies were first produced against a leptospiral genus-specific protein antigen (GP-Ag) isolated from Leptospira interrogans serovar kremastos strain Kyoto. The representative monoclonal antibody (GP-7) did not agglutinate kremastos Kyoto but reacted with Triton X-100 treated kreamastos Kyoto, andamana, patoc and Urawa in enzyme-linked immunosorbent assay (ELISA), indicating that the monoclonal antibody recognized the genus-specific determinant of GP-Ag. The localization of GP-Ag was investigated by immunoelectron microscopy with the iodinated antibody and peroxidase-labeled antibody. The genus-specific determinant of GP-Ag recognized by GP-7 was located on the subsurface of the leptospiral envelope.

Animals↗
PubMed1985

Influence of microinjection of insulin into ventromedial hypothalamus on acetate metabolism in liver slices of rabbit.

Insulin was injected directly into the ventromedial hypothalamic nuclei (VMH) of rabbits, and changes in hepatic acetate metabolism were studied. The injection of 50 microU insulin into the VMH of intact rabbits decreased the rates of 14C transfer from 14C-1-acetate into glucose and cholesterol ester in liver slices. But after insulin injection into the parietal cortex of intact rabbits and into the VMH of rabbits with VMH lesions, hepatic acetate metabolism did not differ from that of the control rabbits, which received saline injection into the same brain regions. These observations support the hypothesis that the VMH are parts of an insulin-sensitive brain regulator system in the hepatic acetate metabolism.

Acetates↗
PubMed1985

An association of mercury with selenium in inorganic mercury intoxication.

Energy dispersive X-ray analysis was performed on the renal tubular cells of two patients with inorganic mercury intoxication. Some lysosomes of these cells consisted of unusual matrices of aggregated electron-dense grains which were positive for mercury, selenium and sulphur. Though maps of the specific X-rays of both mercury and selenium coincided exactly with these lysosomes, the molecular ratio of selenium to mercury ranged between zero and 2.9. It is unlikely that the trace element of selenium and exogenous inorganic mercury are deposited in the lysosomes independent of each other, but rather their coexistence in the characteristic lysosomes strongly suggests a compound formed by binding mercury to the SeH residues of selenoprotein.

Chemical Phenomena↗
PubMed1985

Central hyperglycaemic effect of adrenaline and carbachol.

The effect of chemical stimulation of the brain on glucoregulation was studied in anaesthetized rats. Adrenaline, noradrenaline, acetylcholine, dopamine and carbachol (5 X 10(-8) mol/microliter saline) were injected directly into the third cerebral ventricle and changes in hepatic venous plasma glucose, immunoreactive glucagon and insulin concentrations were studied. The injection of adrenaline and carbachol into the third cerebral ventricle resulted in a marked hyperglycaemia associated with increased immunoreactive glucagon. Adrenaline-induced hyperglycaemia was not affected by bilateral adrenalectomy, while carbachol-induced hyperglycaemia was completely inhibited by adrenalectomy. The injection of somatostatin (1 X 10(-9) mol) with adrenaline into the third cerebral ventricle did not influence adrenaline-induced hyperglycaemia, while carbachol-induced hyperglycaemia was inhibited by co-administration with somatostatin. These results suggest that adrenergic and cholinergic neurons in the central nervous system may increase hepatic glucose output by different mechanism.

Acetylcholine↗
PubMed1985

Effects of aldose reductase inhibitor on retinal microangiopathy in streptozotocin-diabetic rats.

Wistar strain rats were made diabetic by injection of streptozotocin and divided into three groups fed on different diets: conventional solid foods, a fructose-rich diet and a fructose-rich diet mixed with ONO 2235, an aldose reductase inhibitor. The retinas of these rats were examined in flat mount preparations after trypsinization. Microvascular changes such as capillary tortuosity, microaneurysms, pericyte loss, that are typical of diabetic retinal microangiopathy, were seen most frequently in the rats fed on the fructose-rich diet. The rats fed on the fructose-rich diet with ONO 2235 showed much less vascular change than the diabetic rats fed on the conventional food. Electron microscopy of the retina revealed localized thickening of the basement membrane of the retinal capillaries, and this was most frequent in the fructose-fed rats. However, in rats fed on fructose with ONO 2235 the changes of the basement membrane were slight. It was concluded that the aldose reductase inhibitor, ONO 2235, prevented development of diabetic microangiopathy, probably by suppressing the enzymatic activation of aldose reductase in the retina.

Aldehyde Reductase↗