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Biomedical subjects

A Dasmahapatra

Publications and source records attributed to A Dasmahapatra.

9 recordsLinked to original sources
PubMed1992

Erythrocyte Ca, Na/K-ATPase in long-term streptozotocin diabetic rats. Effect of good glycemic control and a Ca antagonist.

This study evaluated the effect of chronic hyperglycemia on erythrocyte membrane Ca and Na/K-ATPase activities in streptozotocin-induced diabetic rats. The activity of Ca-ATPase was significantly lower in diabetic than in normal rats. Good glycemic control by insulin restored the Ca-ATPase activity to normal. By contrast, diltiazem, a calcium entry blocker, had no effect on the enzyme activity. Calmodulin stimulated Ca-ATPase activity in all groups of rats. Na/K-ATPase activity was not altered in diabetic rats, and no effects of either insulin or diltiazem treatments were observed. The results suggest that erythrocyte Ca-ATPase activity is decreased in diabetic rats and is normalized by good glycemic control.

Animals↗
PubMed1992

Platelet sodium-hydrogen antiport in obese and diabetic black women.

In this investigation we correlated platelet Na-H antiport parameters with blood pressure and serum lipids in a sample population of non-insulin-dependent diabetic obese, nondiabetic obese, and nondiabetic nonobese black women. Parameters of the Na-H antiport were examined in aspirin-treated platelets. These parameters were not altered in resting or in thrombin-stimulated platelets of diabetic patients. The activity index of platelet Na-H antiport after thrombin stimulation was positively correlated with the blood pressure (systolic blood pressure, r = 0.5320 and p = 0.0001; diastolic blood pressure, r = 0.5123 and p = 0.0017). Lower high density lipoprotein cholesterol levels were associated with an alkaline shift in the cytosolic pH set point for activation of the Na-H antiport. Highly significant correlations were also observed between the total cholesterol/high density lipoprotein cholesterol ratio and the cytosolic pH set point for activation of the Na-H antiport. These correlations were independent of diabetes or the body mass index. Together, these observations indicate that parameters of platelet Na-H antiport are altered with an increase in blood pressure and a decrease in serum high density lipoprotein cholesterol.

Adult↗
PubMed1991

Fingerstick glucose determination in shock.

OBJECTIVE: To evaluate the accuracy of fingerstick glucose measurements in severely hypotensive patients. DESIGN: Prospective, nonrandomized comparison study. SETTING: Emergency department in a university hospital. PATIENTS: Twenty-five severely hypotensive patients (systolic blood pressure less than or equal to 80 mm Hg) and 39 normotensive patients. MEASUREMENTS: Simultaneous fingerstick reagent strip glucose, venous reagent strip glucose, and laboratory glucose values were compared. Data were analyzed using error-grid analysis. RESULTS: In hypotensive patients, the mean fingerstick glucose values were significantly lower than the values obtained either by venous reagent strip or laboratory glucose measurements. Fingerstick glucose values in the hypotensive group were 67.5% of laboratory glucose values, and were significantly lower than the values obtained in the normotensive group (91.8%, P less than 0.001). Only 36% of the hypotensive patients had fingerstick glucose values within the acceptable range of 20% of the laboratory glucose value. Thirty-two percent of hypotensive patients were incorrectly diagnosed as hypoglycemic (glucose less than 3.89 mmol/L [70 mg/dL]); 2 of these patients were actually hyperglycemic (glucose greater than 11.10 mmol/L [200 mg/dL]). Venous reagent strip measurements accurately reflected laboratory glucose values in both hypotensive and normotensive patients. CONCLUSIONS: Fingerstick glucose testing does not accurately represent venous glucose levels in severely hypotensive patients. If fingerstick glucose testing is relied on for these patients, errors in clinical management may be made. Venous reagent strip glucose testing correlates well with laboratory glucose measurements and should be the preferred method for rapid assessment of glucose level in critically ill patients with severe hypotension.

Blood Glucose↗
PubMed1987

Sorbinil partially prevents decreased erythrocyte deformability in experimental diabetes mellitus.

The ability of red blood cells (RBCs) to undergo an adaptation in shape that permits passage through the smallest vessels is reportedly impaired in diabetes. Several hypotheses have been proposed to explain decreased erythrocyte deformability, which has been implicated in the pathogenesis of microvascular complications, but the mechanisms responsible for this change have not been clearly delineated. In view of the fact that sorbitol accumulates in RBCs in diabetes and the postulate that increased sorbitol could alter deformability properties, we examined the influence of the aldose reductase inhibitor sorbinil on erythrocyte deformability. Erythrocyte deformability, determined as the volume of RBCs (VRBC) filtered per minute through 4.7-micron pore size filters, was significantly reduced in samples from diabetic rats compared with samples from controls (0.76 +/- 0.03 vs. 0.97 +/- .02 ml RBC/min; P less than .001). In contrast, deformability of RBCs from diabetic animals treated with sorbinil was significantly greater than in untreated diabetes, although not completely normalized (0.88 +/- 0.02; P less than .01 vs. diabetic, and P less than .02 vs. control). The reduced deformability characterizing cells from diabetic rats and its partial prevention by sorbinil persisted even when RBCs were washed to eliminate hyperglycemia and hyperviscous plasma. Thus, hyperviscosity per se is not responsible for the decreased deformability, and sorbinil can partially prevent this change despite persistent hyperglycemia. This effect may derive from sorbinil's action as an aldose reductase inhibitor and/or its ability to influence physicochemical properties of the erythrocyte membrane.

Animals↗
PubMed1986

Evaluation of adenosine deaminase activity in patients with head and neck cancer.

ADA is a key enzyme in the mammalian purine salvage pathway. The lack of ADA activity has been linked to a lack of cellular immunity in various immune and myeloproliferative disorders. Data on its role in patients with solid tumors are scant and inconclusive. In this report, we have evaluated the activity of this enzyme in the peripheral lymphocytes of patients with head and neck squamous cell cancer (HNC). The mean ADA activity in Stage IV patients (0.57 +/- 0.08 SEM, n = 12) was significantly lower than that of controls (1.55 +/- 0.25 SEM, P less than 0.05, n = 14) and also significantly lower that the mean ADA activity in patients with Stages I, II, and III (1.14 +/- 0.10 SEM, P less than 0.05, n = 17). Fourteen out of 19 controls, Stage I, II, and III patients had positive skin tests compared to 7 out of 10 Stage IV patients. These differences were not statistically significant. There was also no correlation between ADA activity and the absolute lymphocyte counts. Our results indicate that ADA activity in lymphocytes of patients with advanced HNC is lower than that of controls or patients with earlier stages of the disease. ADA may be a more sensitive indicator of suppressed cellular immunity than delayed cutaneous hypersensitivity reactions, or monitoring absolute lymphocyte counts.

Adenosine Deaminase↗
PubMed1985

Decrease by cycloheximide of calcium binding and nonesterified fatty acids in rat-intestinal Golgi-enriched membrane fractions.

Rat intestinal Golgi-enriched membrane fractions bind more Ca2+ than do basolateral and microvillus-enriched membrane fractions, and this uptake is reduced by vitamin D-deficiency. The effect of the protein synthesis inhibitor, cycloheximide, on this Ca2+ binding was determined in rat fed a normal, vitamin D-sufficient diet. Cycloheximide, 1.5 mg/kg, rapidly reduced protein synthesis (measured by [3H]leucine incorporation) to 12% of control values within 15 min, but Ca2+ binding diminished gradually to 50% of control values by 60 min. Ca2+ transport across gut sacs was also decreased. The reduction in Ca2+ binding was not due to an alteration in vesicle morphology or to a direct effect of cycloheximide. Nonesterified (free) fatty acids, the probable binding sites for Ca2+ in these membrane fractions, were reduced by cycloheximide to 48% of control values by 60 min. There was no significant change in total lipid phosphate. Cycloheximide may affect the synthesis of proteins necessary for the presence of nonesterified fatty acids in these Golgi membranes.

Animals↗
PubMed1985

Erythrocyte sodium/potassium adenosine triphosphatase in thyroid disease and nonthyroidal illness.

Thyroid hormone is known to modulate cell membrane sodium/potassium adenosine triphosphatase (Na/K-ATPase). To determine whether the activity of this enzyme differed in patients with nonthyroidal illness with low levels of circulating thyroid hormones and patients with documented clinical hypothyroidism, we measured Na/K-ATPase activity in red blood cells from patients with hypo- and hyperthyroidism, patients with nonthyroid disease with and without reduced circulating levels of thyroid hormone, and normal subjects. We also assessed whether the activity of this enzyme reflects decreased thyroid hormone action at the cellular level in patients with nonthyroidal illness. Hyperthyroidism was associated with decreased and hypothyroidism with increased erythrocyte Na/K-ATPase activity [142 +/- 24 (+/- SE) and 371 +/- 37 nmol Pi/mg X h; P less than 0.05 and P less than 0.01 compared to normal]. Enzyme activity in cells from patients with nonthyroidal illness and low levels of circulating T3 was significantly higher than that in cells from normal subjects (289 +/- 11 vs. 223 +/- 16 nmol Pi/mg X h; P less than 0.01), but was not significantly different from that in cells from hypothyroid patients. Red cell Na/K-ATPase activity in patients with nonthyroidal illness and normal thyroid function tests (185 +/- 38 nmol Pi/mg X h was indistinguishable from normal values. These data confirm that hyperthyroid patients have decreased red cell Na/K-ATPase activity and provide direct evidence that erythrocyte ATPase activity is increased in hypothyroid patients. The change in enzyme activity in patients with nonthyroidal illness and decreased circulating T3 levels was comparable to that in hypothyroidism. These results suggest that since red cell Na/K-ATPase activity does not distinguish between ill patients with low thyroid function tests and those with hypothyroidism, tissue hypothyroidism may exist in the former group of patients.

Adolescent↗
PubMed1985

Reduced glomerular sodium/potassium adenosine triphosphatase activity in acute streptozocin diabetes and its prevention by oral sorbinil.

To explore metabolic changes associated with the sorbitol accumulation and myo-inositol depletion observed in glomeruli of rats with experimental diabetes, we examined total and ouabain-inhibited adenosine triphosphatase (ATPase) activity in glomeruli isolated from control and streptozocin (STZ)-diabetic rats. Glomerular Na/K-ATPase activity (ouabain-inhibited) was significantly reduced in diabetic animals, while total (composite) ATPase activity remained unchanged. Treatment with insulin partially restored the Na/K-ATPase activity. Administration of the aldose reductase inhibitor, sorbinil, which normalizes glomerular contents of both sorbitol and myo-inositol in diabetes, completely prevented the diminution of Na/K-ATPase activity. These results establish that glomerular Na/K-ATPase activity is reduced in acute experimental diabetes. The ability of sorbinil to prevent this decrease suggests that it is related to polyol accumulation and/or myoinositol depletion, although an effect of the drug unrelated to its aldose reductase inhibiting property has not been excluded. Since increased polyol pathway flux, decreased myo-inositol, and reduced Na/K-ATPase activity have also been described in peripheral nerve, another tissue in which typical diabetic complications characteristically occur, the consequences of these metabolic changes may be implicated in the pathogenesis of diabetic nephropathy.

Adenosine Triphosphatases↗