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Biomedical subjects

N J Lewiston

Publications and source records attributed to N J Lewiston.

60 records · Page 4Linked to original sources

Intracellular edema and dehydration: effects on energy metabolism in alveolar macrophages.

The effects of intracellular edema and dehydration on energy metabolism in alveolar macrophages were studied. Intracellular edema increased lactate production and reversibly decreased oxygen consumption. Dehydration caused no significant change in lactate production but irreversibly decreased oxygen consumption. These phenomena may be applicable to a wide variety of clinical problems including lung and brain edema.

Animals↗

Clinical observations on mechanical ventilation for respiratory failure in bronchiolitis.

An unusually large number of infants (82) were admitted to Stanford University Hospital from November 1, 1983, through May 31, 1985, with a diagnosis of bronchiolitis requiring oxygen therapy. A larger percentage of these infants (17/82 = 21%) than generally expected required mechanical ventilation for respiratory failure. Fourteen infants had respiratory syncytial virus (RSV) infections, and three had parainfluenza virus infections. Ten patients had respiratory difficulties as neonates. The mechanical ventilation of the children requiring respiratory assistance was characterized by high minute ventilation with high tidal volumes (15 to 20 ml/kg) and slow respiratory rates (16 to 22 breaths/min). Peak inspiratory pressure averaged (mean +/- SD) 35 +/- 6 cm H2O in the RSV group and 34 +/- 6 cm H2O in the parainfluenza group. The mean number of days on the ventilator was 9.7 +/- 3.1 for the RSV group and 8.3 +/- 2.9 for the parainfluenza group. All were extubated within 17 days of presentation and discharged within 28 days. The complications encountered included pneumothorax and acute pulmonary hypertension.

Bronchiolitis, Viral↗

Oral correction of essential fatty acid deficiency in cystic fibrosis.

A combination of pancreatic insufficiency and inadequate caloric intake may produce essential fatty acids (EFA) deficiency in patients with cystic fibrosis. Seventy-five percent of the adolescents and young adults with poor weight gain in our clinic were EFA-deficient by total plasma linoleic acid criteria. Twenty of these patients were placed on an oral hyperalimentation regimen containing 230% of calories required for basal energy expenditure, 40% as fat. Forty percent of these (8/20) achieved normal EFA levels on this diet. Eight of the nonresponding patients were given an additional 5% of their caloric intake as linoleic acid monoglyceride. All who maintained caloric intake achieved normal EFA levels. Normalization of EFA levels was associated with a number of clinical benefits including increase in weight and activity and, in five teenage girls, regulation of menses. The 16 control patients who received standard pancrelipase therapy and nutritional supplements remained fatty acid deficient. We conclude that oral hyperalimentation can restore EFA levels in cystic fibrosis patients if adequate calories are available to provide energy needs.

Cystic Fibrosis↗

Sudden death in adolescent asthma.

There has been an increase in mortality from asthma in the adolescent age group in the past several years. Although the exact cause of this is not known, a number of factors probably contribute. We have identified four areas of major concern which we believe place adolescents with asthma at high risk. These include physiological factors such as night-time worsening of disease (or "dipping"), non-compliance with the medical regimen, stress associated with daily living and parental expectation, and depression/suicide with asthma as the modality. Identification of those individuals who are at risk and intervention into the contributory factors may reduce asthma deaths.

Adolescent↗

Clinical significance of hyperbilirubinemia in patients with pulmonary hypertension undergoing heart-lung transplantation.

Hyperbilirubinemia is commonly observed in long-standing pulmonary hypertension and is thought to be the result of chronic right ventricular failure and subsequent liver congestion. To evaluate the clinical significance of preoperative hyperbilirubinemia, we reviewed the cases of 62 patients with pulmonary hypertension (31 primary and 31 Eisenmenger's syndrome) who underwent heart-lung transplantation between 1981 and 1990 at Stanford. Bilirubin levels higher than 1.0 mg/dl were noted in 58% of patients, and bilirubin levels higher than 2.0 mg/dl were noted in 23% of patients. Indirect hyperbilirubinemia accounted for 66% to 87% of the total bilirubin and tended to fluctuate with diuretic therapy. It was associated with polycythemia, reticulocytosis, and mild elevations of liver enzymes. Early postoperative mortality in patients with total bilirubin levels greater than 2.1 mg/dl, bilirubin levels greater than 1 mg/dl but less than 2.0 mg/dl, and levels less than 1 mg/dl was 58%, 27%, and 16%, respectively (p less than 0.05). In those with high bilirubin levels, four patients had severe hemorrhage as part of their terminal event. Cardiac cirrhosis was found at autopsy in 75% of the early deaths of patients with high bilirubin. We conclude that hyperbilirubinemia is a late manifestation of pulmonary hypertension. The mechanism of hyperbilirubinemia is probably the result of the combination of increased hemolysis and decreased uptake by the chronically congested liver. Patients with pulmonary hypertension and hyperbilirubinemia appear to be at greater surgical risk during heart-lung transplantation.

Adult↗