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Biomedical subjects

C H Cole

Publications and source records attributed to C H Cole.

9 recordsLinked to original sources
PubMed1979

Bicarbonate-activated ATPase activity in renal cortex of chronically acidotic rats.

The effect of chronic NH4Cl-induced acidosis on the activity of a bicarbonate-activated component of ATPase was studied in homogenates of renal tissue from Wistar rats. This particular component of ATPase, which is maximally stimulated by 50 mM bicarbonate, and is insensitive to the action of ouabain, has been implicated in the active transport of bicarbonate in various tissues. The activity of this enzyme in cortical homogenates from an acidotic group of animals was 4.3 +/- 0.4 mumol Pi/mg protein per hour compared with 5.8 +/- 0.3 mumol Pi/mg protein per hour in a control group (p less than 0.02). No significant change in bicarbonate ATPase activity was observed in medullary homogenates, and NaK-ATPase activity remained the same in cortex and medulla of both groups. Subcellular fractionation of the cortical tissue homogenates revealed that bicarbonate ATPase activity in a microsomal fraction from acidotic animals was 6.5 +/- 1.1 mumol Pi/mg protein per hour compared with 9.4 +/- 1.2 mumol Pi/mg protein per hour in control animals (p less than 0.02). Bicarbonate ATPase activity in other subcellular fractions was not different in the two groups of animals. These findings are compatible with the hypothesis that a certain percentage of bicarbonate reabsorption in the nephron is mediated by a bicarbonate-activated component of ATPase.

Acidosis↗
PubMed1976

Alteration in intracellular sodium concentration and ouabain-sensitive ATPase in erythrocytes from hyperthyroid patients.

The activity of the ouabain-sensitive sodium-potassium-activated component of the ATP-hydrolyzing enzyme system (ouabain sensitive ATPase) was studied in the erythrocyte membranes of 10 patients with hyperthyroidism, and found to be decreased in all 10 patients. The mean ouabain-sensitive ATPase activity was 43 +/- 4 nmol Pi/mg tissue/h in the patients, compared with 69 +/- 5 nmol Pi/mg tissue/h in the erythrocyte membranes of 10 paired control subjects. The mean concentration of sodium within the erythrocytes was 10.8 +/- 0.9 nmol/liter of red blood cells in the patients and 7.2 +/- 0.3 nmol/liter of red blood cells in the controls. The decrease in ouabain-sensitive ATPase activity did not appear to be associated with a change in the ligand sensitivity of ATPase, nor was there a difference in the activity of the ouabain-insensitive component of ATPase. Serial studies to follow the effects of treatment of hyperthyroidism on red cell membrane ATPase were performed repeatedly in one of these patients. There was a significant inverse correlation between L-thyroxine (T4) and ouabain-sensitive ATPase, as both variables returned to normal. Normal erythrocyte membranes were assayed for ATPase activity in the presence of varying concentrations of L-triiodothyronine (T3) and T4, and following pre-incubation with T4. No significant effect on erythrocyte membrane ATPase was demonstrated in either series of experiments. It can be concluded from these studies that the decreased sodium efflux in the erythrocytes of patients with hyperthyroidism is associated with a decrease in the activity of the ouabain-sensitive component of ATPase in the erythrocyte membrane. The failure to reproduce this effect in vitro suggests that it does not represent a direct effect of the thyroid hormones on the mature erythrocyte membrane.

Adenosine Triphosphatases↗
PubMed1975

Changes in erythrocyte membrane ouabain-sensitive adenosine triphosphatase after renal transplantation.

1. Intracellular electrolytes, and erythrocyte membrane adenosine triphosphatase (ATPase) activity, was studied in twenty patients after renal transplantation. 2. The mean ouabain-sensitive ATPase activity in the erythrocyte membranes of the transplant patients was 122 nmol of inorganic phosphorus (Pi) h-1 mg of tissue-1 (SEM 14), compared with 62 nmol of Pi h-1 mg of tissue-1 (SEM 8) in a group of paired, healthy controls. 3. The increase in ouabain-sensitive ATPase was most marked in the 4 months after transplantation. However, a significant increase in ouabain-sensitive ATPase persisted for more than 8 months after transplantation. 4. This increase in ouabain-sensitive ATPase was associated with a decrease in intracellular sodium in the erythrocytes of the transplant patients.

Adenosine Triphosphatases↗
PubMed1975

Inhibition of ouabain-sensitive ATPase by the saliva of patients with cystic fibrosis of the pancreas.

A study has been made of the effect of saliva from children with cystic fibrosis of the pancreas (CFP) on various components of the ATP hydrolyzing enzyme system. The ouabain-sensitive ATPase activity of erythrocyte membranes prepared from intact erythrocytes preincubated with CFP saliva was 35 +/- 4 nmol Pi/mg fry wt membrane suspension/hr, compared with 48 +/- 7 nmol Pi/mg dry wt membrane suspension/hr when the erythrocytes were preincubated with control saliva. A calcium-activated component of ATPase was decreased from 202 +/- 30 nmol Pi/mg dry wt membrane suspension/hr in erythrocytes preincubated with control saliva, to 151 +/- 17 nmol Pi/mg dry wt membrane suspension/hr when the incubation was carried out with CFP saliva. In a second series of experiments, ultrafiltered saliva was added directly to an ATPase assay. The saliva from children with CFP brought about a mean decrease in ouabain-sensitive ATPase of 16% compared with control saliva.

Adenosine Triphosphatases↗
PubMedDate not supplied

Auditory and ophthalmological findings in children with acute lymphoblastic leukemia.

The audiological and ophthalmological function in 59 children in continuous complete remission for at least 2 years since the completion of therapy for acute lymphoblastic leukemia was evaluated. Three of 42 tested had abnormal hearing assessments, but none was attributed to the leukemia or its treatment. Four of 54 patients had visual abnormalities: 3 had mild refractive errors and 1 patient had mild subcapsular cataracts consistent with steroid-induced cataracts. We conclude that as the frequency of visual and hearing impairment in these patients is low, it is not necessary to perform audiological or ophthalmological assessment during routine follow-up unless clinically indicated.

Adolescent↗