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Biomedical subjects

Y Okuda

Publications and source records attributed to Y Okuda.

At least 361 records · Page 20Linked to original sources
PubMed1986

Basis and practice of clinical taste examinations.

Separate taste examinations of each area of gustatory innervation are necessary in clinical practice in treating patients with taste disorders. We have developed our own electrogustometer with a dB scale and qualitative and quantitative clinical gustometry using filter-paper discs (the filter-paper disc method). this paper reports on our main basic studies in this field and new insights and experience gained in connection with the two gustometry procedures. Reference is made to the gustatory pathway, innervation area on the tongue and the soft palate, the argument against the localization theory of taste, the correlation between electrogustometry and the filter-paper disc method, differential diagnosis of taste disorders using both methods and the effective use of these methods in clinical practice. The effective use of both methods of measurements is important to give the physician assurance and confidence in the diagnosis and treatment of taste disorders.

Adolescent↗
PubMed1986

Effects of parenteral palatinose on glucose metabolism in normal and streptozotocin diabetic rats.

The present experiment was carried out to investigate the metabolism of palatinose (6-O-alpha-D-glucopyranosyl-D-fructose) in the rat. The bolus injection of palatinose (0.5 g/kg) in the tail vein of normal and streptozotocin (STZ) diabetic rats caused significant increments in glucose and insulin concentrations. However, in severe STZ diabetic rats (greater than 300 mg/dl of fasting plasma glucose) no significant change in glucose and insulin concentrations was observed. In liver perfusion, the gradual decrease in glucose output from the normal and mild STZ diabetic rat livers perfused with 20 mM Krebs-Ringer-Tris buffer pH 7.4 was prevented by the addition of 5.5 mM palatinose in the perfusate and fructose was detected in the effluent during the palatinose infusion. The results indicate that palatinose is metabolized to glucose and fructose in both normal and diabetic rat tissues, and this causes the increase in blood glucose concentration. On the other hand, the direct stimulatory effect of insulin release from pancreatic B-cell was not observed when the palatinose was infused into the isolated perfused rat pancreas. The study suggest that palatinose administered parenterally is metabolized by tissues and expected to be used as a source of fluid and energy supply.

Animals↗
PubMed1986

Time course of ketone body production in the isolated perfused rat liver in response to various stimuli.

Using a non-recirculating perfusion system, we studied the time course of ketone body output from the isolated rat liver in response to various hormones and changes in pH and redox state. The release of 3-hydroxybutyrate (3-OHB) started to be suppressed within 1 min after the addition of insulin (50 mU/ml) and kept half of the basal level even 10 min after its cessation. The addition of glucagon (0.2 microM) caused an increase in both 3-OHB and acetoacetate (AcAc) outputs from fed livers within 5 min, which reached about 150% of the basal level 10 min after the infusion and maintained a constant level through out the experiment. Growth hormone (2 mu/ml) elicited a slight but significant increase in AcAc output soon after the infusion. Epinephrine (10 microM) also caused a slight increase in both AcAc and 3-OHB outputs 9 min after the infusion and maintained a significant increase even 10 min after stopping infusion. The decrease in pH of the perfusate or the addition of ascorbic acid abruptly suppressed the AcAc production. In summary, the present study clearly demonstrated the direct effects of various hormones on ketogenesis in the liver and the usefulness of a non-recirculating liver perfusion system as a tool for the study of ketogenesis.

Animals↗
PubMed1986

Palatinose as a potential parenteral nutrient: its metabolic effects and fate after oral and intravenous administration to dogs.

Palatinose (6-O-alpha-D-glucopyranosyl-D-fructose) is a naturally occurring compound which may be valuable as both a sweetener and parenteral nutrient. Its advantage over maltose is that its hydrolysis generates both fructose and glucose. In the present study, conducted with a view to possible clinical use, its metabolic effects and fate after iv injection were investigated. Using dogs as the experimental model, it was found that the behavior of parenterally administered palatinose is in many respects similar to maltose and is likely to be clinically valuable. Importantly, hypertriglyceridemia, a side effect of fructose administration, did not occur, indicating that palatinose may be superior to the use of fructose alone.

Administration, Oral↗
PubMed1985

Effects of substance P and substance P-(6-11) on hormone release from isolated perfused pancreas: their opposite actions on rat and canine islets.

The effects of substance P (SP) and SP-(6-11) (SP6-11) on hormone secretion from the isolated perfused pancreas were compared in rats and dogs under the same conditions. In the rat, SP inhibited insulin secretion in a dose-dependent manner in a concentration range of 0.1-10 nM. Glucagon secretion was inhibited at a minimal dose of 10 nM SP. No significant effect on somatostatin secretion was obtained. SP6-11 exhibited the identical inhibitory potency as SP on both insulin and glucagon release from the rat pancreas. In the canine pancreas, by contrast, 1 and 10 nM SP and SP6-11, respectively, potentiated the release of insulin, glucagon, and somatostatin. Potentiation by SP6-11 was less than that by SP. These results demonstrate species differences in the effects of SP and SP6-11 on the release of pancreatic hormones.

Animals↗
PubMed1985

Changes in blood glucose and insulin after an oral palatinose administration in normal subjects.

Changes in plasma glucose and insulin concentration in response to palatinose ingestion were compared with those to sucrose in eight normal volunteers. When 50 g of palatinose was administered, the plasma glucose gradually increased to its peak of 110.9 +/- 4.9 mg/dl at 60 min after administration and maintained a plateau during the 120 min of the experiment. The peak value of plasma glucose to 50 g sucrose in the same group was 143.3 +/- 8.8 mg/dl at 30 min after administration and then the value sharply decreased to the fasting level. The cumulative increase in plasma glucose (sigma delta PG) to palatinose was significantly smaller than that to sucrose. The changes in the plasma insulin level almost paralleled those in the plasma glucose level. These results indicate that palatinose is more slowly absorbed than sucrose and therefore useful as a sweetener for diabetic patients.

Administration, Oral↗
PubMed1985

[An experimental study on adhesion blocking in simultaneous injury of tendon and nerve].

The formation of adhesions between simultaneously injured tendon and nerve with and without adhesion blocking materials was studied by using a rabbit model. A collagen membrane, produced from adult bovine corium and with a negative electric charge induced by chemical modification, was used as the blocking material. Microangiography and histological studies were performed to investigate the vascular supply to the adhesions. The following results were obtained. Blood vessel proliferation was observed parallel to the adhesion formation. The vessels to the adhesions originated mainly from intraneural and perineural vascular plexuses. The collagen membrane was effective in preventing the development of adhesions by restricting the blood supply. Within 5 weeks, the collagen membrane was almost absorbed, and healing of tendon and nerve was almost complete.

Animals↗
PubMed1984

Ultrastructure of ovarian follicles in in vitro perfused rabbit ovaries: response to human chorionic gonadotropin and comparison with in vivo observations.

Ovulation may be achieved and studied in an isolated perfused rabbit ovary upon inclusion of human chorionic gonadotropin (hCG) in the perfusion fluid. The ultrastructural features of the rabbit ovarian follicle prior to ovulation in vitro were compared with those in vivo. The perifollicular vasculature was also examined in in vitro perfused rabbit ovaries during the preovulatory interval. Granulosa cells of the preovulatory follicle share many ultrastructural features in vivo and in vitro; however, only small amounts of smooth endoplasmic reticulum (sER) were observed in granulosa cells in vitro after hCG. Ovulation after hCG in the in vitro preparation tends to occur earlier (6 hours) than in vivo (12 hours). Thus, there may be insufficient time and/or gonadotropin exposure to permit full functional development of granulosa cells, as reflected by reduced amounts of sER. Degradation of collagen fibrils was less prominent in the theca externa and tunica albuginea in vitro than in in vivo. Perifollicular capillaries became dilated after hCG, but interendothelial gaps were not observed. Disappearance of surface epithelium in the apex of follicles was similar in vitro and in vivo.

Animals↗