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Biomedical subjects

J Okuda

Publications and source records attributed to J Okuda.

At least 199 records · Page 11Linked to original sources

Anomeric compositions of D-glucose in tissues and blood of rat.

The anomeric compositions of D-glucose in the liver, kidney, heart, blood and plasma of rat were determined by our methods for the assay of D-glucose anomers and the percentages of the beta-anomer were found to be 61.8, 61.0, 62.4, 62.7 and 62.9, respectively.

Adipose Tissue↗

Metabolism of injected flavins studied by using double-labeled [14C]flavin adenine dinucleotide and [14C, 32P]flavin mononucleotide.

The metabolism of flavins in mouse was studied with [F-(2)-14C, A-(2,8)-14C]FAD and [F-(2)-14C, 32P]FMN. Ninety minutes after injection, radioactive isoalloxazine nucleus of double-labeled FAD was markedly incorporated into FAD, FMN and riboflavin in the liver, whereas a small amount of radioactive adenine nucleus of double-labeled FAD was found in FAD in the liver. In the case of FMN, radioactive isoalloxazine nucleus of double-labeled FMN was markedly incorporated into FAD, FMN and riboflavin in the liver, whereas only a minute amount of radioactive phosphorus was incorporated into FMN and FAD in the same organ. These results indicate that FMN and FAD injected are rapidly hydrolyzed and resynthesized in animal body.

Animals↗

D-Glucose anomeric preference of hexokinases in higher animals.

The D-glucose anomeric preference of hexokinases isolated from rat liver, brain, and skeletal muscle, and bovine retina was studied using the glucose-6-phosphate dehydrogenase-NADP system. The ratios of maximum phosphorylation rates of beta-D-glucose to those of alpha-D-glucose were 1.33, 1.46, and 1.54 for hexokinase types I, II, and III from rat liver, 1.45 and 1.63 for type I from rat brain and bovine retina, 1.53 for type II from rat skeletal muscle, and 0.55 (when determined at 5 mM) for type IV (glucokinase) from rat liver, respectively.

Animals↗

Uptake of D-glucose anomers by rat retina.

Uptake of D-glucose anomers by isolated rat retina was studied. After 3 min incubation at 37 degrees C in the presence of alpha or beta anomer (750 mug/ml), a significantly greater uptake (1.32 mg/g wet tissue) of beta-anomer was observed compared with that of alpha-D-glucose (1.11 mg/g wet tissue). This result and other data suggest that the carrier for D-glucose transport in the retina prefers the beta-anomer stereospecifically.

Animals↗

Rapid and sensitive, colorimetric determination of the anomers of D-glucose with D-glucose oxidase, peroxidase, and mutarotase.

A modification, utilising mutarotase, of an enzymic, colorimetric system for determining D-glucose with D-glucose oxidase, peroxidase, and ABTS was satisfactory for the assay of the anomers of D-glucose in aqueous solution. The time required for a single assay is approximately 10 min, and the lower limit is 0.4 microgram of D-glucose. The method is applicable to the anomer analysis of D-glucose released by enzymic hydrolysis of D-glucosides.

Carbohydrate Epimerases↗

[Endoscopic electromyographic study on upper gastrointestinal tract (author's transl)].

Recently we made the electromyographic study on human gastrointestinal tract using the endoscopic method is useful for the clinical studies of the patho-physiological aspects on human gastrointestinal tract. The silver bipolar needle electrode which was 0.2 mm in diameter, 10 mm in length and 1.0 mm in interpolar distance and the electroencephalography recorder provided with pen-writer were used for this research. The endoscopy was done to the volunteer anesthetized his pharynx with xylocaine spray. 20 cases of gastro-electromyograms, 35 cases of duodeno-electromyograms and 5 cases of the electromyograms of duodenal papilla were recorded. On these endoscopic electromygorams, the typical rhythms and patterns of electrical activities were disturbed by various kinds of factors; that is, on the endoscopic manipulation, the sticking of needle electrode into the shallow layer of gastrointestinal wall and automatical pouring of water into canal through the endoscope. On volunteers' condition, his deep breathing, electrocardiogram and vasotonic condition were important factors. Typical duodeno-electromyograms showed the grouped spikes synchronizing with the duodenal peristalsis observed endoscopically. The electromyograms of the duodenal papilla showed the similar patterns and rhythms to those of duodeno-electromyograms on active phase. In the clinical study on the correlation and propagation between gastric and duodenal motility, the rhythms of electrical activities on duodeno-electromyograms were not similar to the rhythms of gastric peristalsis at the prepyloric region. The propagation of gastric movement to duodenal bulb were not able to be clarified. We assumed that the gastric and duodenal motility occurred each other on the different rhythms.

Adult↗

Uptake of radioactive D-glucose anomers by pancreatic islets.

Isolated rat islets were incubated in media containing either the alpha or beta anomer of D-[1-3H]glucose for 5 min at 37 degrees. The amounts of the two anomers incorporated were determined using L-[1-14C]glucose as an extracellular space marker. The incorporation of beta-D-glucose was about twice that of alpha-D-glucose. Our previous and present results suggest that the two anomers of D-glucose each have a preferential function in pancreatic beta cells; alpha-D-glucose stimulates insulin secretion, and beta-D-glucose is transported into the cells.

Animals↗

Insulin secretion by anomers of d-glucose.

Isolated rat islets were incubated for 5 minutes in the media containing either the alpha or beta anomer of D-glucose (2 milligrams per milliliter). The amounts of secreted insulin and changes of anomers ratio were concomitantly determined. In spite of rapid mutarotation, significantly greater stimulation of insulin secretion was observed by alpha-D-glucose as compared with beta-D-glucose.

Animals↗