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Biomedical subjects

I Mineo

Publications and source records attributed to I Mineo.

47 records · Page 3Linked to original sources
PubMed1986

Increased plasma uric acid after exercise in muscle phosphofructokinase deficiency.

Type VII glycogenosis (muscle phosphofructokinase deficiency) is attended by hyperuricemia and hyperuricosuria. In one patient, we found that exercise on a bicycle ergometer increased plasma uric acid, inosine, and hypoxanthine levels. Forearm exercise also markedly increased venous inosine, hypoxanthine, and ammonia in the exercising arm of two patients. Exaggerated release of precursors for uric acid synthesis from exercising muscle may be related to the hyperuricemia.

Adult↗
PubMed1985

Excess purine degradation in exercising muscles of patients with glycogen storage disease types V and VII.

To investigate purine catabolism in exercising muscles of patients with muscle glycogen storage disease, we performed ischemic forearm exercise tests and quantitated metabolites appearing in cubital venous blood. Two patients with glycogen storage disease type V and three with glycogen storage disease type VII participated in this study. Basal lactate concentrations lowered in every patient with glycogen storage disease type V or type VII. Two patients with glycogen storage disease type VII, who had markedly elevated concentrations of serum uric acid (14.3 and 11.9 mg/dl, respectively), showed high basal concentrations of ammonia (118 and 79 mumol/liter, respectively; 23 +/- 4 mumol/liter in healthy controls) and of hypoxanthine (23.4 and 20.4 mumol/liter, respectively; 2.0 +/- 0.4 mumol/liter in healthy controls). Other patients showed near normal measurements of these metabolites. After forearm exercise, ammonia, inosine, and hypoxanthine levels increased greatly in every patient studied, in contrast with the lack of increase in lactate levels. The incremental area under the concentration curves for venous ammonia was 13-fold greater in the glycogen storage disease group than in controls (1,120 +/- 182 vs. 83 +/- 26 mumol X min/liter). The incremental areas of inosine and hypoxanthine were also greater in the glycogen storage disease group (29.2 +/- 7.2 vs. 0.4 +/- 0.1 and 134.6 +/- 23.1 vs. 14.9 +/- 3.2 mumol X min/liter, respectively). The incremental areas of ammonia in controls and in glycogen storage disease patients strongly correlated with those of hypoxanthine (r = 0.984, n = 11, P less than 0.005). These findings indicated that excess purine degradation occurred in the exercising muscles of patients with glycogen storage disease types V and VII, and suggested that the ATP pool in the exercising muscles may be deranged because of defective glycogenolysis or glycolysis.

Adult↗
PubMed1984

Decreases in hepatic fructose-2,6-bisphosphate level and fructose-6-phosphate,2-kinase activity in diabetic mice: a close relationship to the development of ketosis.

Hyperglycemic mice with streptozotocin diabetes were divided into two groups according to the presence or absence of ketosis. No difference in blood glucose level between two groups was observed in this experiment. However, hepatic fructose-2,6-P2 level and fructose-6-P,2-kinase activity were decreased only in ketotic diabetic mice. Similar decreases in those indices were observed in 48-h starved normal mice. In ketotic diabetes, insulinization for 24 h was required to normalize fructose-2,6-P2 level and fructose-6-P,2-kinase activity, while glucose administration normalized altered fructose-2,6-P2 metabolism in starvation only in 30 min. Hepatic cyclic AMP was increased neither in ketotic nor in non-ketotic diabetic mice. These results indicate that the decrease in hepatic fructose-2,6-P2 level in diabetes is apparently related to the occurrence of ketosis, but not to hyperglycemia. The mechanisms of the decrease in fructose-6-P,2-kinase activity in ketotic diabetes and starvation are discussed.

Animals↗
PubMed1984

A comparative study on glucagon effect between McArdle disease and Tarui disease.

Pretreatment with glucagon relieved patients with McArdle disease from muscular symptoms during exercise and enhanced exercise performance, though it did not produce any improvement in patients with Tarui disease. The difference in glucagon effect between the two diseases was clearly demonstrated in the bicycle ergometer exercise tests. In addition, the semi-ischemic forearm exercise tests performed after glucagon injection showed that increased lactate production was significantly induced by exercise in McArdle disease, but it was not the case in Tarui disease. In McArdle disease, the augmentation in exercise-induced lactate production was also observed after administration of glucose, or glucose plus insulin, but it was neither observed after administration of insulin alone nor after arginine or epinephrine administration. These findings suggest that the beneficial effect of glucagon in McArdle disease is due to the enhanced utilization of circulating glucose through the muscular glycolytic pathway realized in the coexistence of hyperglycemia and hyperinsulinemia.

Adult↗
PubMed1984

Kinetic properties of erythrocyte phosphofructokinase in patients with type VII glycogenosis from two families--close similarity to liver type phosphofructokinase.

The kinetic properties of phosphofructokinases (PFKs) from normal human liver, muscle and erythrocytes, and from erythrocytes of two unrelated patients with type VII glycogenosis (muscle PFK deficiency, McKusick 23280) were analysed in this study. Sensitivity to inhibition by ATP and to inhibition by 3-phosphoglycerate, 2-phosphoglycerate, phosphoenolpyruvate and citrate were quite different for muscle and liver PFKs. The kinetic characteristics of normal erythrocyte PFK were intermediate between those of muscle and liver PFKs. The kinetic constants of erythrocyte PFK of a patient in one family were indistinguishable from those in the other family. In addition, kinetic behaviour of residual PFK activity in erythrocytes from patients in the two families were quite similar to those of normal liver PFK. These results of kinetic analyses provide convincing evidence for the concept that normal erythrocyte PFK consists of muscle and liver type subunits. Residual erythrocyte PFK activity in type VII glycogenosis is thus concluded to reflect the activity of liver type PFK existing in patient's erythrocytes.

Adolescent↗
PubMed1984

Metabolic basis of improved exercise tolerance: muscle phosphorylase deficiency after glucagon administration.

A 26-year-old girl with muscle phosphorylase deficiency had exercise intolerance and experienced an occasional "second wind" phenomenon. Muscle glycogen concentration was about three times the normal level, whereas each glycolytic intermediate below the phosphorylase step was equivalent to only 10% of a normal level. Semi-ischemic forearm exercise tests disclosed no elevation of the venous lactate or pyruvate level, but they showed remarkable increases of serum creatine kinase and ammonia. Glucagon administration markedly augmented exercise tolerance. Forearm exercise after glucagon injection significantly increased venous lactate. Thus, the beneficial effect of glucagon is attributable to blood glucose utilization by muscle.

Adult↗
PubMed1983

Prevalence of diabetic retinopathy and distribution of its severity among patients of a university clinic of diabetes in Osaka.

We have been following longitudinal changes of diabetic retinopathy by periodic fundoscopy in patients at our out-patient clinic for diabetes mellitus. In this study, we reviewed the prevalence of diabetic retinopathy and the distribution of its severities. Funduscopic examinations for retinopathy were performed on 242 patients. They ranged in age from 13 to 84 years (52.9 +/- 0.9, mean +/- s.e.). Duration of diabetes ranged from 1 to 31 years (10.7 +/- 0.4). Forty patients were treated with diet alone, 112 with oral hypoglycemic agents and 90 with insulin administration. No retinopathy was found in 83 patients (34%), background retinopathy in 113 (47%), preproliferative retinopathy in 24 (10%) and proliferative retinopathy in 17 (7%). Five patients (2%) were blind. Twenty-seven patients (60%) of 45 with a less than 5-year duration of diabetes were apparently without retinopathy, while the incidence of proliferative retinopathy increased in proportion to the duration. Fasting plasma glucose and glycosylated hemoglobin levels were higher in the patients with proliferative retinopathy than in any other group. All of the blind patients had a long history of untreated diabetes. Whether diabetic control assessed by glycosylated hemoglobin influences the progression of retinopathy could not be demonstrated by a 2-year observation. Further analysis based on a longer duration is needed in this respect.

Adolescent↗