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Biomedical subjects

K Asayama

Publications and source records attributed to K Asayama.

At least 127 records · Page 7Linked to original sources
PubMed1984

Lipid profiles and lipase activities in children and adolescents with chronic renal failure treated conservatively or with hemodialysis or transplantation.

To elucidate the pathogenesis of hyperlipidemia in chronic renal disease in children and adolescents, we have measured serum triglyceride, total cholesterol, high density lipoprotein cholesterol (HDL-C) and activities of postheparin plasma lipoprotein lipase and hepatic triglyceride lipase (EC 3.1.1.3) in nine patients with transplants, and nine hemodialyzed and 18 conservatively treated patients with chronic renal failure. In 29 of 36 patients, serum insulin levels both in fasting and in response to oral glucose load were measured. The lipase activities were measured separately, utilizing antiserum against hepatic triglyceride lipase. All groups of patients had hypertriglyceridemia. The patients with endogenous creatinine clearance less than 20 ml/min/m2 had a low HDL-C level. The HDL-C level was correlated inversely with serum triglyceride level and positively with glomerular filtration rate. The lipoprotein lipase activities were low in patients with endogenous creatinine clearance less than 20 ml/min/m2. Although hepatic triglyceride lipase activities were not significantly low in any groups of patients, they were correlated with glomerular filtration rates in the conservatively treated patients with chronic renal failure. A defective triglyceride removal due to low lipase activities may contribute to uremic hypertriglyceridemia in these patients. On the other hand, patients with transplants had almost normal lipase activities and exhibited hyperinsulinemia; overproduction of triglyceride due to hyperinsulinemia may contribute to their hypertriglyceridemia.

Adolescent↗
PubMed1984

Alloxan-induced free radical production in isolated cells. Selective effect on islet cells.

Chemiluminescence, as a direct measure of oxygen free radical production, induced in isolated cells, hepatocytes, and red cells by the action of alloxan has been measured. The assay system used luminol, 3 microM, for signal amplification. The buffer used was Krebs-Ringer bicarbonate with 16 mM Hepes, pH 7.4. This buffer did not react with alloxan in the absence of cells. Some chemiluminescence was noted from all cells in the absence of alloxan. In the presence of alloxan, reactions occurred within seconds and islet cells were significantly more reactive to alloxan than either red cells or hepatocytes as defined by alloxan dose-response curves with fixed cell numbers or fixed surface areas. These data indicate a cell specificity for an early action of alloxan perhaps mediated at the cell membrane.

Alloxan↗
PubMed1984

Chemiluminescence as an index of drug-induced free radical production in pancreatic islets.

Chemiluminescence induced in isolated islets from rat pancreas by the diabetogenic drugs, alloxan and streptozotocin, has been measured. The assay system consisted of 3 microM of luminol, 10 islets, and 100 microM of alloxan or 500 microM of streptozotocin in 5 ml Krebs-Ringer bicarbonate buffer containing 16 mM of Hepes (pH 7.4). Alloxan-induced chemiluminescence appeared very rapidly and lasted more than 5 min. On the other hand, streptozotocin failed to produce chemiluminescence over a period of 60 min after addition. The presence of superoxide dismutase (1000 U/ml) and/or catalase (100 U/ml) markedly suppressed alloxan-induced chemiluminescence. These results suggest that alloxan acts as an exogenous free radical generator in pancreatic islets, but that streptozotocin does not. The involvement of superoxide anion and hydrogen peroxide in production of chemiluminescence by alloxan suggests that the hydroxyl radical may mediate this chemiluminescence.

Alloxan↗
PubMed1983

Serum lipids and postheparin plasma lipase activity in Japanese children with ketosis-prone diabetes mellitus.

Using a selective immunochemical method, the activities of postheparin plasma lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) were measured in 7 children with newly diagnosed IDDM, 39 on a conventional subcutaneous insulin regimen (CSC), and 11 children receiving continuous subcutaneous infusion of insulin (CSII). The newly diagnosed untreated patients frequently had hypertriglyceridemia and a decreased serum HDL-cholesterol level, while they showed a mild, but not significant increase of the serum total cholesterol level. The insulin-treated patients (both on CSC and on CSII) had serum lipid levels similar to those in controls. LPL activity was decreased in untreated patients, and insulin treatment resulted in an increase in the LPL activity with a concomitant normalization of serum triglyceride and HDL-cholesterol levels. In contrast to the patients on CSII who had normal LPL activity, patients on CSC had an increased LPL activity. This may have been due to peripheral hyperinsulinemia. HTGL activity did not show any increase during the time of improved diabetic control. In conclusion; (1) serum lipid levels were normal both in the patients on CSC and CSII. (2) LPL activity was normal on CSII, but was increased on CSC and decreased in untreated patients.

Child↗
PubMed1983

The improved response in endogenous insulin due to continuous subcutaneous infusion of insulin therapy in juvenile diabetes.

We investigated the relationship between the recovery or improved response of endogenous insulin and the control of blood glucose in juvenile diabetes (IDDM) treated with the continuous subcutaneous infusion of insulin (CSII). (1) It is unlikely that the decrease in endogenous insulin secretion over several years following onset of IDDM in 43 subjects was uniform in terms of urinary c-peptide (u-CPR) excretion. (2) In 27 newly diagnosed cases of IDDM, the group receiving CSII (n = 18) showed more satisfactory results, including greater stability of blood glucose, a more rapid decrease in insulin requirements and an earlier improvement in u-CPR compared to the control group who were receiving conventional subcutaneous insulin therapy (n = 9). (3) U-CPR increased with the improvement in blood glucose control within 2 to 4 wks of the initiation of CSII in 6 of 8 already-treated cases of IDDM, while daily insulin requirements did not differ significantly before and after CSII. Since short-term CSII therapy improved u-CPR response by normalizing blood glucose not only in newly diagnosed but also known diabetic, therapy should be directed toward the long-term intensive control of blood glucose in order to maintain the potency of endogenous insulin secretion especially in newly-diagnosed cases of insulin secretion especially in newly-diagnosed cases of IDDM.

C-Peptide↗
PubMed1982

In vivo insulin sensitivity and insulin binding to erythrocytes in children: insulin resistance in obese children.

This aim of this study was to determine whether RBC insulin receptor assay represents a clinically useful way of assessing insulin sensitivity in obese children. Steady state plasma glucose (SSPG) was established by a constant infusion of glucose (6 mg/kg/min), insulin (0.8 mU/kg/min) and somatostatin (125 micrograms/m2/h), following the loading dose of somatostatin (125 micrograms/m2). Insulin binding to RBCs was measured by a modified method of Gambhir and was compared with SSPG. Of 21 children with various relative body weight, 8 hyperinsulinemic obese children had a decreased insulin binding to RBCs due to decreased receptor concentrations. The insulin binding was inversely correlated with the fasting serum insulin level and with the insulin area under the O-GTT insulin response curve. In 11 children with various relative body weight, a highly significant inverse relationship was found between SSPG and insulin binding. SSPG was also correlated with the fasting serum insulin level. It was concluded that RBC insulin receptor may quantitatively reflect insulin resistance in obese children, and may be a useful tool for clinical evaluation of tissue insulin sensitivity in children.

Adolescent↗
PubMed1981

Effects of thermal load on ion release of the rabbit vitreous body.

Ion-release of the rabbit vitreous body through a dialysis membrane against water was studied. To evaluate one of thermal changes in the vitreous properties, the vitreous was heated or cooled before dialysis. The average wet weight of the normal vitreous was 1.61 +/- 0.20 g and dry to wet weight ratio was 1.33 +/- 0.04%. The dry weight, sodium, potassium, and chloride concentrations of the vitreous were decreased as an exponential function curve by dialysis. A decreasing ratio was prominent in the heated vitreous, the frozen vitreous and the non-thermo-treated (control) vitreous in turn. Calcium and magnesium release from the rabbit vitreous body was slow and differences among the heated, frozen and non-thermo-treated vitreous bodies were not significant, suggesting some different capture-mechanisms between the monovalent and bivalent ions.

Animals↗