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Biomedical subjects

Y Shigeta

Publications and source records attributed to Y Shigeta.

At least 235 records · Page 13Linked to original sources
PubMed1981

Clinical significance of altered insulin sensitivity in diabetes mellitus assessed by glucose, insulin, and somatostatin infusion.

Insulin sensitivity has been determined in primary nonobese diabetics and subjects with borderline glucose intolerance by a newly devised technique using glucose, insulin, and somatostatin infusion. Insulin sensitivity for glucose utilization was decreased in both adult- and juvenile-onset diabetics. Eight out of 88 diabetics had normal insulin sensitivty and were free from microvascular complications. In lean subjects with borderline glucose intolerance, insulin sensitivity was decreased, although an overlap with normal was noted. All obese subjects with borderline glucose intolerance had reduced insulin sensitivity. An inverse relationship was observed between insulin sensitivity and fasting plasma glucose (FPG), and a significant correlation was observed between FPG and steady state plasma glucose levels (SSPG; r = 0.57; P less than 0.001). Improvement of diabetic control in eight diabetics with sulfonylureas decreased SSPG in all (P less than 0.05), although normalization of SSPG was observed in only one. These results indicate that decreased sensitivity of insulin for peripheral glucose utilization may play an important role in the pathogenesis of diabetes. Elevated FPG levels reflect the presence of decreased insulin sensitivity in diabetes mellitus. Although decreased sensitivity is difficult to normalize, it can be enhanced by improving the diabetic control. An effort to maintain or enhance tissue insulin sensitivity in diabetes mellitus may be more important than attempts to stimulate the deteriorating pancreatic beta-cells to secrete more insulin.

Adolescent↗
PubMed1981

Effect of age and sex on insulin binding to human erythrocytes.

Insulin binding to erythrocytes from normal subjects over a wide range of ages (group I, cord blood; group II, Age 6M to 6 yrs; group III, 7 to 19 yrs; group IV, 20 to 59 yrs, group V, over 60 yrs of age) was determined using modified Gambhir's method and the effect of age and sex on the binding was evaluated. The highest insulin binding to cord blood erythrocytes was accounted for by the increased number of reticulocytes since there was a highly significant correlation between insulin binding and the reticulocyte count (r = 0.928, p less than 0.001). Group IV showed significantly higher binding than younger are groups II and III. The mean binding in group V was the highest among all age groups except for group I, although the differences failed to reach statistical significance. The receptor concentrations (R0) were comparable among groups except group I which had a slightly increased R0. The affinity of insulin receptors was the lowest in group I and II, and gradually increased with the age and a positive correlation (p less than 0.01) was obtained between age and Ke. This increase in affinity with age is considered an adaptive response to the intracellular metabolic derangement often seen in the aged. No effect of sex on insulin binding was seen before puberty. However, in normal adults insulin binding of the female tended to be lower than that of the male with slightly increased R0 and decreased affinity in the female. Thus, the slightly decreased binding of the female group was mainly accounted for by the decreased affinity although the difference in the affinity was not significant.

Adolescent↗
PubMed1981

Immunoreactivity and biologic activity of semisynthetic [LeuB-30]-insulin: potential value in the treatment of insulin antibody-mediated insulin resistance.

Insulin analogues with different amino acids, including threonine, alanine, L-leucine, D-leucine, L-leucine amide, phenylalanine, tri-alanine, or desalanine, at the B-30 position were semisynthesized from pork insulin by the new enzymatic method. The order of ability of the insulin analogues to bind to anti-insulin sera was [AlaB-30] greater than desalanine greater than [ThrB-30] greater than [Ala-Ala-AlaB-30] greater than [D-LeuB-30], [Leu-NH2B-30],[PheB-30] greater than desoctapeptide greater than or equal to [LeuB-30]. The ability of insulin analogues with different amino acids at B-30 to bind to receptors, as well as their biologic potency tested with glucose uptake in isolated rat adipocytes, was comparable among the analogues. These results suggest that [LeuB-30]-insulin demonstrated the least immunoreactivity and has full activity in receptor binding and biologic effect, and that it may be useful for treatment of anti-insulin antibody-mediated insulin resistance.

Adipose Tissue↗
PubMed1980

HLA antigens as immunogenetic markers of alcoholism and alcoholic liver disease.

HLA antigens were studied among 94 chronic alcoholics. Concerning A and B-loci, there was no significant change of phenotype frequency (PF) in the HLA typing between the patients and controls (80 healthy subjects). However, there was a significant difference in the PF of CW3 between chronic alcoholics and controls (58.5% in alcoholics vs 30.0% in controls). The corrected p value was less than 0.05 with relative risk value being 3.29 HLA-DR loci were also detected in 26 patients, but there was no significant difference between the patients and controls. All alcoholics were subdivided according to the hepatic morphology, and the PF of HLA was examined. A significant high frequency of HLA CW3 was found in patients with hepatitis (64%) compared to controls (30%). There was also an increased PF of CW3 in the liver cirrhosis group (59% in cirrhosis group vs 30% in controls). In conclusion, chronic alcoholics have a significantly higher PF of HLA-CW3 as compared to controls. This characteristic feature becomes even more distinct in alcoholics with severe hepatic lesions.

Adult↗
PubMed1980

Significance of serum gamma glutamyl transpeptidase as a marker of alcoholism.

To study the effect of chronic ethanol administration on the activity of gamma glutamyl transpeptidase (GGTP) in various tissues, female rats were pair-fed liquid diets with 36% of total calories either as ethanol or as isocaloric carbohydrate (controls). Six weeks of ethanol feeding resulted in a significant increase of cytochrome P450 content. Hepatic microsomal GGTP activity was almost doubled after ethanol feeding whether expressed per g of liver or per mg of microsomal protein. Furthermore, intestinal GGTP activity was significantly enhanced after ethanol, whereas there was no change in the enzyme activity in either kidney or pancreas. There was a concomitant elevation of plasma GGTP activity. Phenobarbital administration to rats resulted in an enhancement of GGTP activity in the liver whether given orally or intraperitoneally. In addition, intestinal GGTP activity after oral phenobarbital was also significantly increased, although its activity after intraperitoneal administration was not enhanced. These results suggest that enhanced hepatic and intestinal GGTP activities may contribute, at least in part, to an increased level of serum GGTP frequently seen in chronic alcoholics.

Alcoholism↗
PubMed1980

Evaluation of the method of insulin binding studies in human erythrocytes.

A modified erythrocyte insulin receptor assay was developed. The major advantage of our method is the smaller amount of blood necessary for the assay and consequent simple handling in the binding assay. Three ml of blood is enough for this assay, making it possible to assess insulin receptors in a group of pediatric patients. There was a close relationship between mononuclear cells and erythrocyte insulin binding assays (r = 0.900, p < 0.05). With this method insulin binding studies were done on normal subjects and adult onset non-obese diabetics. Decreased insulin binding was seen in the diabetic group, and this was due to a decreased number of insulin receptors. This erythrocyte insulin receptor assay can be useful tool for the study of the mechanism of insulin resistance.

Animals↗
PubMed1980

Effect of propranolol on glucose disposal rate in patients with hyperthyroidism.

The effect of propranolol treatment (60 mg per day, three days) on glucose disposal rate (K-value) was investigated in nine patients with hyperthyroidism. K-value was improved in 4 cases and aggravated in 5 cases. The fasting levels of plasma free fatty acids (FFA) before the administration of propranolol in the improved cases were significantly higher than those in the aggravated cases. The propranolol treatment markedly reduced FFA levels only in the improved cases. These results suggest that the impaired glucose tolerance frequently seen in hyperthyroidism patients could be partly attributed to the increased level of plasma FFA.

Adult↗
PubMed1980

Receptor mediated insulin degradation decreased by chloroquine in isolated rat adipocytes.

The time-course of insulin binding to isolated adipocytes pretreated with chloroquine (0.1 mM) showed that no steady state condition was reached and that the binding kept increasing with the time of incubation up to three hours. Sixty-one percent of the bound labeled insulin could not be dissociated from these cells by 100 microgram/ml of unlabeled insulin, whereas 86% dissociated from the control cells. Chromatography revealed that the bound intact insulin, which had the ability to bind to insulin receptors of adipocytes, was increased and that degraded insulin decreased in the chloroquine treated cells. However, these cells showed normal insulin stimulation of 2-deoxy-glucose uptake. The data suggest that insulin is internalized in adipocytes after binding to insulin receptors and that insulin is degraded at the site, probably lysosomes, where chloroquine inhibits this degradation process.

Adipose Tissue↗