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Biomedical subjects

J Okuda

Publications and source records attributed to J Okuda.

At least 163 records · Page 9Linked to original sources
PubMed1984

The effect of some ointment bases on the systemic absorption of tobramycin from various wound surfaces of burned patients.

Three kinds of 0.2 per cent tobramycin ointment were prepared with tobramycin and 3 ointment bases (cream, polyethylene glycol and hydrophilic petrolatum), and applied to the various wound surfaces of 5 burned patients. The systemic absorptions of tobramycin were compared with the values of the tentative AUC (area under the curve of tobramycin blood level, micrograms.h/ml.g) until 12 hours after the applications, by determining tobramycin level in blood. Similar values of AUC from the cream and polyethylene glycol ointments were obtained, while that of hydrophilic petrolatum ointment was very low. The systemic absorption of tobramycin from the polyethylene glycol ointment was studied when the ointment was applied to the wound surfaces of 7 patients with partial-thickness burn, 9 patients with full-thickness burn and 6 patients with burn ulcer. The mean values of the tentative AUC of patients with partial-thickness burn, full-thickness burn and burn ulcer were found to be 0.06, 0.03 and 0.15, respectively. These results showed that cream and polyethylene glycol bases should be used carefully as a vehicle of tobramycin ointments because of the rapid systemic absorption of tobramycin from human burn wounds, especially burn ulcer.

Absorption↗
PubMed1984

Affinity of mutarotase for Sephadex and glycogen.

It was found that hog kidney mutarotase has an affinity for Sephadex G-100, equilibrated and eluted with 5 mmol/l EDTA buffer (pH 7.4), resulting in retardation of its elution from the column. The affinity was reduced depending upon the presence of 0.15 mol/l NaCl and 0.2 mol/l glucose, separately or in combination. A small portion of mutarotase was adsorbed to rabbit liver glycogen as judged from the column chromatography of a mixture of the two on Bio-Gel P-100. Mutarotase was adsorbed to neither dextran nor raw potato starch.

Animals↗
PubMed1984

D-glucose anomeric preference of hexokinases from animals and yeast.

The D-glucose anomeric preference of hexokinases partially purified from animals (rat, mouse, and chicken) and baker's yeast (Saccharomyces cerevisiae) were investigated by the assay system with glucose-6-phosphate dehydrogenase as a coupling enzyme. With low Km hexokinases in animal tissues and cells, the ratios of Vmax for the beta-anomer to Vmax for the alpha-anomer (V beta/V alpha) were within a range from 1.3 to 1.5. In yeast, the V beta/V alpha value was 1.1 for hexokinase A, 0.8 for hexokinase B, and 1.4 for glucokinase. The possible explanation for D-glucose anomeric preference of hexokinase is discussed.

Animals↗
PubMed1984

Inhibition of glucokinase in hepatocytes by alloxan.

The effect of alloxan on glucokinase in isolated rat hepatocytes was studied. Exposure of hepatocytes to alloxan (3 mM) at 30 degrees C for 5 min produced a marked inhibition (77%) of glucokinase activity and altered slightly the phosphofructokinase activity (32% inhibition). Pyruvate kinase and glucose 6-phosphate dehydrogenase, however, were not inhibited at all. Alloxan induced a concentration-dependent inhibition of glucokinase activity with a detectable inhibition at an alloxan concentration of 1 mM. The inhibition of glucokinase activity by alloxan was protected by the simultaneous presence of 15 mM hexose such as D-glucose, 3-O-methylglucose, or D-mannose. D-Galactose showed no protective effect. These results suggest that alloxan may exert its cytotoxic action through the inhibition of glucokinase activity not only in the liver but also in the pancreatic islets, since liver and islet glucokinases are known to be quite similar in various properties.

Alloxan↗
PubMed1984

[Calcifying mucinous adenocarcinoma of the stomach--case report].

In a patient with mucinous adenocarcinoma of the stomach and metastatic lesions in the lung and lymph nodes , X-ray films demonstrated multiple punctuate calcifications. We collected reported cases of gastric cancers with radiographically visualized calcium deposits and discussed their characteristics.

Adenocarcinoma, Mucinous↗
PubMed1983

Multiple forms of mutarotases from the kidney, liver, and small intestine of rats: purification, properties, subcellular localization and developmental changes.

Comparative studies of mutarotase [aldose 1-epimerase, EC 5.1.3.3] from the kidney, liver and small intestine of rats were performed placing in the focus on the study of multiple forms. The findings obtained are as follows. Mutarotases from the kidney and liver of adult rats were both separated into four forms (types I-IV) by DEAE-cellulose column chromatography, whereas only two forms (types I and II) were detected in the small intestine. Liver mutarotase type I was further separated into types I1 and I2 by column chromatography on hydroxylapatite. Types I and II from the kidney and type II from the liver were purified to homogeneity as judged by isoelectric focusing on thin layer polyacrylamide gel. Of various physicochemical properties, only the Km for alpha-D-xylose and the isoelectric point were different among the multiple forms. Liver mutarotase was immunohistochemically localized in the nuclei of parenchymal cells and small intestine enzyme in the nuclei of mucosal cells, indicating similarity with the localization of kidney enzyme (in the nuclei of epithelial cells of renal tubules and glomeruli) which was reported in our previous paper [Experientia (1979) 35, 1094-1097]. The kidney mutarotase level increased gradually after birth and reached a maximum near adult level within 20 days. This developmental pattern was essentially the same as that in the liver but clearly different from that in the small intestine, in which the mutarotase activity of suckling rats was several times higher than that of adult rats. Distribution patterns of multiple forms (types I-IV) of the enzyme in the kidney and liver of 10-day-old rats were similar to those in respective tissues of adult rats. On the other hand, the small intestine of 10-day-old rats contained four forms (types I-IV), whereas there were only two forms (types I and II) in adult rats.

Aging↗
PubMed1983

Suppression of afferent activity of the hepatic vagus nerve by anomers of D-glucose.

Afferent discharges were recorded from the nerve filaments dissected from the hepatic branch of the vagus nerve in the guinea pig. Recordings were made in isolated and perfused liver preparations and in vivo to study the effect of alpha and beta anomers of D-glucose on the afferent discharge rate. Infusions of these anomers (30 mg or 50 mg dissolved in 10 ml glucose-free Ringer solution) into the portal vein in perfused liver preparations and intraportal injections of these anomers (50 mg/kg dissolved in 0.2 ml saline) in vivo partially suppressed the afferent activity. However, the effect of suppression by the beta anomer was stronger than that of the alpha anomer. Results indicate the existence of anomeric stereospecificity of D-glucose action to the hepatic "glucose sensors."

Afferent Pathways↗
PubMed1983

Different effects of D-glucose anomers on enhanced motility of the stomach.

The injection of alpha, beta, or equilibrated (alpha: 36%, beta: 64%) D-glucose solution into the cranial side of carotid artery decreased gastric pressure caused by insulin in rats with bilateral adrenalectomy. This effect was not reproduced after vagotomy at the cervical level. The effect of beta-D-glucose was more rapid and potent than that of alpha-D-glucose. The injection of isotonic NaCl solution, however, produced no change in pressure.

Adrenalectomy↗
PubMed1983

Preference of glucokinase for the alpha anomer of hexose: relation to alpha-anomer preference in hexose-induced insulin release by pancreatic islets.

The alpha anomers of glucose and mannose were more rapidly phosphorylated than the beta anomers by rat liver glucokinase, whose chromatographic and kinetic properties are known to be quite similar to those of pancreatic islet glucokinase. This result may explain our previous findings of the alpha-anomeric preference in glucose- and mannose-stimulated insulin release, and therefore suggests to support the hypothesis that glucokinase in islets functions as a crucial hexose sensing enzyme for insulin release induced by glucose and mannose.

Animals↗
PubMed1982

Inhibition of aldose reductases from rat and bovine lenses by flavonoids.

Thirty flavones, four isoflavones and thirteen coumarins were tested as inhibitors of lens aldose reductase, which is believed to participate in the initiation of cataract formation in diabetes. Many were found to be potent inhibitors, and the two most potent ones were axillarin (5,7,3',4'-tetrahydroxy-3,6-dimethoxyflavone) and 6,3',4'-trihydroxy-5,7,8-trimethoxyflavone (LARI 1). These two flavones inhibited aldose reductase purified from rat lens with IC50 values of 2.6 X 10(8) and 3.6 X 10(8) M respectively. They also inhibited aldose reductase purified from bovine lens with IC50 values of 1.8 X 10(7) M. The potencies of the two compounds were superior to those of all the previously reported inhibitors of aldose reductase. Inhibition of rat and bovine lens aldose reductases by the two compounds was of a non-competitive type with DL-glyceraldehyde as the variable substrate. Some flavones including axillarin and LARI 1 were found to be poorly or scarcely inhibitory against several adeninenucleotide-requiring enzymes, which are involved in glycolysis and other metabolic reactions. These results obtained show that the two flavones have some features which may be required in clinically useful drugs for diabetic patients. All the potent inhibitors of the compounds tested had a flavone skeleton, one (or two free) hydroxyl(s) in ring C, and more than three hydroxyls (free or methylated) in ring A. The possible relationships of structures to inhibitory potencies of the compounds tested are discussed.

Aldehyde Reductase↗
PubMed1982

Non-enzymatic reduction of alloxan by reduced nicotinamide nucleotide.

Much evidence has been reported that the diabetogenic action of alloxan is caused by the formation of cytotoxic free radicals during the autoxidation of dialuric acid, a reduction product of alloan, to alloxan. The mechanism by which alloxan is reduced in vivo to dialuric acid, however, is unknown. The non-enzymatic reaction of alloxan with NAD(P)H was studied as a possible candidate for the reduction of alloxan. The reaction was carried out at 37 degrees in 50 mM phosphate buffer (mostly at pH 7.0) and was followed by measuring the decrease in absorbance at 340 nm. NADH and NADPH were found to be stoichiometrically oxidized by alloxan to NAD and NADP respectively. When the alloxan concentration (1.0 mM) was kept constant and the concentration of NAD(P)H (0.05 to 0.2 mM) was varied, the rate of decrease in the relative concentration of NAD(P)H was almost constant, suggesting that the autoxidation of dialuric acid by O2 was rapid enough to neglect its presence in the medium. The reaction between alloxan and NAD(P)H was accelerated by decreasing the pH. Both the rate of decrease in NAD(P)H concentration and the rate of O2 consumption resulting from autoxidation of the dialuric acid formed by reduction of alloxan were not affected by the presence of 20 mM D-glucose. Ethylene formation by the reaction of methional with . OH, one of the autoxidation products of dialuric acid, was clearly reduced by the presence of alpha- or beta-D-glucose (20 mM), but there was no significant difference between the effects of the two anomers. These results with D-glucose ruled out the possibility that the protection of beta-cells by D-glucose against the diabetogenicity of alloxan can be explained either by its inhibitory action on dialuric acid formation or by its scavenging effect on . OH.

Alloxan↗
PubMed1982

Purification and characterization of multiple forms of mutarotase from hog kidney cortex.

The enzyme mutarotase [aldose 1-epimerase, EC 5.1.3.3] from hog kidney cortex was separated into four fractions (designated types I, II, III, and IV in order of elution) by column chromatography on DEAE-cellulose. Two major forms, types I and II, were purified to homogeneity as judged by polyacrylamide gel electrophoresis and isoelectric focusing on thin layer polyacrylamide gel. Types I, II, III, and IV had isoelectric points of 5.78, 5.48, 5.23, and 5.10, respectively. The following physicochemical properties were common to all four types: molecular weight, 41,000; Km for alpha-D-glucose at pH 7.4 and 25 degrees C, 19 mM; optimum pH, 6.5-7.5; optimum temperature, 30-37 degrees C; heat stability, up to 50 degrees C. On double immunodiffusion, the four types of mutarotase gave single precipitin lines, which fused completely with each other, against the antibody to purified type II enzyme. Types I and II had an identical amino-terminal residue, arginine, and an identical carboxyl-terminal sequence, -(Phe-Phe-Ser-Val)-Val-Ala. The amino acid composition of type I was almost identical with that of type II. Very similar tryptic peptide maps were obtained from types I and II, with only a few points of variance. These results suggest that the four types of hog kidney mutarotase are quite similar but not identical.

Amino Acids↗