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Biomedical subjects

K Doi

Publications and source records attributed to K Doi.

At least 757 records · Page 42Linked to original sources
PubMed1983

Glucagon suppression improves glucoregulation in moderate but not chronic severe diabetes.

To determine the effectiveness of glucagon suppression in improving glucose homeostasis in diabetes, tracer-determined glucose kinetics were measured during a 6-h somatostatin infusion in six alloxan-diabetic dogs (moderately severe diabetes) and five depancreatized dogs deprived of insulin treatment for 3 days (prolonged severe diabetes). Plasma immunoreactive glucagon (IRG) decreased 70 +/- 9% in the alloxan-diabetic and 80 +/- 4% in the depancreatized dogs. Portal vein levels of plasma immunoreactive insulin (IRI) fell (17.0 +/- 2.3 to 4 micro.5 +/- 0.4 microU/ml) as did peripheral vein IRI levels (6.7 +/- 0.9 to 4.7 +/- 0.5 microU/ml) in the alloxan-diabetic dogs. In the depancreatized dogs plasma IRI levels were undetectable. Plasma glucose concentrations fell (278 +/- 17 to 169 +/- 12 mg/dl) during IRG suppression in the alloxan-diabetic dogs due to a rapid and sustained decrease in glucose production (Ra) (6.0 + 0.9 to 3.6 + 0.3 mg X kg-1 X min-1). Glucose disappearance (Rd) decreased gradually (5.9 + 0.6 to 3.9 + 0.2 mg X kg-1 X min-1). In contrast, in the depancreatized dogs, IRG suppression did not alter glucose concentrations or kinetics. Thus, glucagon suppression decreased glycemia by decreasing Ra only in moderately severe diabetes. However, this was associated with decreased rather than improved glucose utilization. The ineffectiveness of glucagon suppression during prolonged severe diabetes could relate to the degree and duration of the metabolic derangement and/or indicate that the continuous presence of some insulin is necessary for glucagon suppression to improve glucose homeostasis.

Alloxan↗
PubMed1983

Neoplastic lesions in streptozotocin-treated rats.

Pathological examination was carried out on 16 male Sprague-Dawley rats received single i. v. injection of 60 mg/kg of streptozotocin (SZ) at 5 weeks of age and maintained for 22 months. Insulinoma (63%), renal adenoma (50%), hepatocellular tumor (69%), cholangioma (31%) and Leydig cell tumor (56%) were found in a high incidence, and therefore occurrence of these tumors was considered to be attributable to the treatment with SZ. In addition to these tumors, though in a low incidence, various such tumors as leukemia, reticulum cell sarcoma, mammary tumor and glioma were also found.

Animals↗
PubMed1983

Influence of dietary fiber (konjac mannan) on absorption of vitamin B12 and vitamin E.

The subjects of this study were six normal and five maturity onset diabetics. On the first day of the study, subjects were given a control test meal, prepared by adding vitamin B12 3000r (mecobalamin) and vitamin E 500 mg (tocopherol acetate), after a 12-hr overnight fast. Then, on the second day in the case of the normal subjects, and on the seventh day in the case of the diabetic subjects, the subjects received a second test meal with 3.9 g konjac mannan (glucomannan). Venous blood samples were taken immediately before the test meal and again after 1, 3, 5, 8, 12 and 24 hr for analysis of vitamins. The absorption rate of vitamin E into the intestine was reduced when konjac mannan was added to the test meals, but that of vitamin B12 was not reduced in normal or diabetic subjects. It is suggested that konjac mannan reduces fat-soluble vitamin absorption removing bile acids, but does not reduce fat-insoluble vitamin absorption in the intestine.

Adult↗
PubMed1983

Brain-tumor imaging using radiopaque perfluorocarbon. A preliminary report.

Perfluorocarbon, a new tumor-seeking x-ray contrast agent, was injected into three rats with experimental brain tumors. After 1 to 3 days the rats were sacrificed, and the brains were removed and subjected to x-ray study. All showed dense radiopaque areas which correlated with the size and shape of the corresponding brain tumors. Conversely, none of the radiograms taken of the brain tumor in five rats receiving no perfluorocarbon (control animals) showed similar increased density. These findings suggest that perfluorocarbon may serve a useful role as a contrast medium for computerized tomography studies of brain tumors in man.

Animals↗
PubMed1983

[Case of primary infiltrating carcinoma in the right breast with metastatic ovarian dysgerminoma].

A 33-year-old woman whose left ovarian dysgerminoma had been resected presented with left axillar swelling and a right breast tumor about three years after surgery. Histological examination of the mastectomized tumor revealed primary infiltrating carcinoma into the muscle layer and a metastatic ovarian dysgerminoma showing well-defined proliferation. Despite chemotherapy, she died 7 months later of breast cancer. To our knowledge, this is the only reported case of its kind in the world literature.

Adult↗
PubMed1982

Role of endocrine pancreas in temperature acclimation.

Role of endocrine pancreas in temperature acclimation in rats was investigated. Plasma glucagon level increased and insulin level decreased in cold-acclimated rats (CA). The reverse was observed in heat-acclimated rats (HA). In the pancreas there were no changes in glucagon and insulin in CA, but a decrease in glucagon and an increase in insulin were found in HA. Plasma insulin/glucagon molar ratio (I/G) declined in CA and rose in HA. Pancreatic I/G rose in HA. Acute cold exposure elevated plasma glucagon, but did not effect plasma insulin. Pancreatic glucagon, insulin and I/G were not influenced by acute cold exposure, while plasma I/G decreased. Plasma I/G was inversely correlated with both blood free fatty acids and glucose levels. These results suggest that endocrine pancreas is closely associated with metabolic acclimation to cold and heat through its regulation of the metabolic direction to catabolic phase in cold acclimation and to anabolic phase in heat acclimation.

Acclimatization↗
PubMed1982

Modified metabolic responsiveness to glucagon in cold-acclimated and heat-acclimated rats.

Calorigenic effect of glucagon on whole body oxygen consumption and interscapular brown adipose tissue (BAT) was investigated in unanesthetized and unrestrained warm controls (WC), cold-acclimated rats (CA) and heat-acclimated rats (HA). Glucagon produced significant elevation of oxygen consumption, body temperature and BAT temperature in all experimental groups. Such increased calorigenic responses to glucagon were significantly potentiated in CA and reduced in HA compared with those in WC. Thermogenic response of BAT to norepinephrine was also similar to that to glucagon; it was potentiated in CA, reduced in HA. These results indicate that glucagon would serve thermoregulatory nonshivering thermogenesis in temperature acclimation as calorigenic hormone, at least in part, through its action on BAT.

Adipose Tissue, Brown↗