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Biomedical subjects

C H Cole

Publications and source records attributed to C H Cole.

At least 19 recordsLinked to original sources

Dilution of nebulised aerosols by air entrainment in children.

Guidelines for use of aerosolised drugs in children are inconsistent. In a study of 14 infants, 22 children, and 4 adults inspired nebulised aerosols were diluted more for large than for small subjects, because of air entrainment which occurred when inspiratory flow exceeded nebuliser flow. Infants under 6 months of age did not entrain air and would receive undiluted aerosols. All other subjects entrained air, which caused up to a 5-fold dilution in inspired aerosol concentration as subject size increased. In subjects who entrained air, the ratio of inspired nebuliser output versus total nebuliser output was relatively constant, and was related to the respiratory pattern. For a given nebuliser solution concentration, infants who do not entrain will inspire more concentrated aerosols than older children. Once entrainment occurs, the mass of drug inspired is largely independent of size. Regimens for nebulised drug delivery in children may require revision.

Adolescent

Tuberculosis and acquired immunodeficiency syndrome--Florida.

Florida reported 1858 cases of the acquired immunodeficiency syndrome (AIDS) and 8455 cases of tuberculosis from January 1, 1981, through October 31, 1986. Of the patients with AIDS, 159 (8.6%) also had tuberculosis, and 154 (1.8%) of the patients with tuberculosis also had AIDS. Among patients with both diagnoses, tuberculosis was diagnosed before AIDS by more than 1 month in 50%, was diagnosed within 1 month before or 1 month after the diagnosis of AIDS in 30%, and was diagnosed more than 1 month after the AIDS diagnosis in 20%. Compared with patients with AIDS only, patients with both diagnoses were also more likely to be Haitian, black (other than Haitian), or Hispanic. Compared with patients with tuberculosis only, patients with both diagnoses were more likely to be younger, male, Haitian, black (other than Haitian), and Hispanic, have extrapulmonary tuberculosis and negative tuberculin skin tests, and have noncavitary chest roentgenograms. These data suggest that patients with AIDS may have an increased risk of tuberculosis and that patients with both diagnoses differ in important demographic and clinical characteristics from patients with AIDS only or tuberculosis only.

Acquired Immunodeficiency Syndrome

ECMO: regional evaluation of need and applicability of selection criteria.

The need and indications for neonatal extracorporeal membrane oxygenation (ECMO) are controversial. The need for ECMO in two New England states was studied through a review of deaths due to respiratory failure in near- and full-term infants. Vermont averaged 2.4 and Maine averaged 7.4 deaths annually. Neither state demonstrated sufficient respiratory deaths to establish ECMO capability. The number of "potential" ECMO candidates, based on published selection criteria, was studied, and the applicability of criteria was evaluated. A two-year review revealed 16 potential candidates from Maine and 19 from Vermont. No criterion accurately identified nonsurvivors of conventional ventilatory therapy. Only one criterion in one institution demonstrated an association with chronic lung disease. The data demonstrated that published ECMO selection criteria were not applicable in different populations.

Extracorporeal Membrane Oxygenation

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

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

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

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