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Biomedical subjects

O R Levine

Publications and source records attributed to O R Levine.

At least 19 recordsLinked to original sources

Sodium deprivation growth failure in the rat: alterations in tissue composition and fluid spaces.

Dietary control of sodium intake was utilized in weanling rats to study the relationships among body growth, tissue composition and extracellular fluid volume (ECFV). Forty 3-wk-old rats were divided into groups receiving 30, 150, 300, 600 or 900 mu eq sodium/d for 5 wk. The minimal daily requirement for normal growth was 300 mu eq Na, or about 60 mu eq/g of new growth. Lower doses caused dose-related growth failure associated with a reduced ECFV. Analyses of carcass, muscle and bone composition were carried out. In sodium-deprived animals there was retarded growth of protoplasm, fat and bone; the mineral composition of muscle was not altered, whereas in bone calcium concentration was reduced. Plasma concentrations of sodium, potassium and chloride remained normal. Pair-feeding indicated that sodium-deficiency growth retardation could not be attributed to starvation. Sodium-deficient animals ingested a greater amount of food per gram of weight gain, possibly reflecting an increased energy expenditure. Sodium deprivation initially permitted protoplasmic growth to proceed at a rate disproportionate to that of the ECFV. Subsequently, both continued to grow at a reduced but similar rate, suggesting that ECFV may be a controller of protoplasmic growth.

Animals

Diuretic-induced growth failure in rats and its reversal by sodium repletion.

The aim of diuretic therapy is the prevention of excessive sodium accumulation. However, sodium retention is necessary for growth. Inasmuch as many of the clinical conditions for which diuretics are used are associated with growth retardation, we investigated the influence of diuretic therapy on growth in an animal model. In Part I, 32 weanling Sprague-Dawley rats were fed a diet adequate for growth which contained 0.08% sodium and 0.17% potassium. Daily i.p. injections of saline (0.4 ml) containing furosemide in doses of 0, 50, 100 or 200 mg/M2 were given for 9 days. There was a dose-related reduction in weight gain which could not be explained by lower food intake. The highest dose group gained only 58% as much as the control group. Balance studies and muscle, bone and carcass analysis demonstrated that this was accounted for by decreases in protoplasmic, bone, fat and extracellular fluid volume accretion. In Part II, 32 weanling rats, all treated daily with furosemide (100 mg/M2 i.p.) received replacement of NaCl, KCl, both or neither in their drinking water. Sodium replacement resulted in increased growth rates whereas potassium replacement alone had no effect on growth. Sodium replacement also increased the balance of all measured minerals. We conclude that diuretic therapy causes growth retardation by preventing retention of sodium needed for growth.

Animals

Cystic lung disease in Down's syndrome: a report of two cases.

Previously unreported lung disease found at autopsy in 2 young infants with Down's syndrome and congenital heart disease (complete atrioventricular canal malformation with left-to-right shunt) is described. The perinatal and neonatal period was unremarkable, and there was no history of mechanical ventilation or administration of high concentration of oxygen for extended periods. In 1 of the cases respiratory symptoms and hyperinflation with focal cystic changes in the lung fields on chest X-ray were noted at 5-7 months of age. Pathologically there was cystic dilatation of alveoli with focal cuboidal metaplasia of alveolar epithelium and mild to moderate focal alveolar septal fibrosis. Wilson-Mikity syndrome, congenital pulmonary lymphagiectasia, bronchopulmonary dysplasia, and idiopathic interstitial fibrosis of lungs were ruled out on clinical and/or pathologic grounds. Factors such as compression of bronchi by enlarged pulmonary arteries or cardiac chambers, peribronchiolar accumulation of fluid, pulmonary hypoplasia occurring in Down's syndrome, and episodes of pulmonary arterial hypoperfusion associated with severe congenital heart disease may be related to the pathogenesis of the lesion.

Cysts

Spontaneous complete closure of a congenital coronary artery fistula.

The first documentation is reported of spontaneous closure of a coronary artery to right ventricle fistula that was demonstrated initially in a 14 month old boy. Over a 4 year period after diagnosis, the characteristic continuous murmur gradually disappeared. When the patient was 5 1/2 years of age, selective coronary arteriography showed normal coronary vessels and circulation. Six other cases of coronary fistula observed during the past 10 years are also reviewed. This study supports the rationale for clinical follow-up rather than obligatory surgical intervention in asymptomatic patients with a small shunt who have no evidence of myocardial dysfunction.

Angiography

Alveolar hypoventilation and cor pulmonale associated with chronic airway obstruction in infants with Down syndrome.

Four infants with Down syndrome developed cor pulmonale and heart failure in association with chronic upper airway obstruction. Features of the sleep apnea syndrome were conspicuous; namely, noisy breathing with retraction, cyanosis and frequent apnea during sleep, and daytime lethargy and somnolence. The clinical picture masqueraded as cyanotic congenital heart disease. Arterial blood gas analyses revealed alveolar hypoventilation, especially during sleep. The nature of the obstructive element was variable. Adenoidectomy provided partial relief in one patient, and tonsillectomy and adenoidectomy resulted in temporary improvement in two others. Three patients were markedly benefitted by tracheostomy. Functional inspiratory pharyngeal closure was demonstrated fluorographically in one patient. Infants with Down syndrome may be predisposed to upper airway obstruction by virtue of hypoplasia of facial and oropharyngeal structures and generalized hypotonia. Additional obstructive elements may be contributed by hypertrophied lymphoid tissue, excessive secretions, and glossoptosis. Removal of the obstructive element is helpful, but functional obstruction may only be relieved by tracheostomy.

Airway Obstruction

Real time ultrasonic evaluation of the fetal heart.

A series of measurements of cardiothoracic ratios (C/T) at various gestational ages are reported. Thirty fetuses ranging from 16 to 36 weeks gestational age were studied using real time ultrasonography. The cardiothoracic ratio remained constant regardless of gestational age. A case report is presented in which a congenital heart malformation was detected in utero using real time ultrasonography, illustrating the value of these measurements in selected cases.

Adolescent

Pulmonary single circulation dilution curves of T-1824, sodium, and tritiated water in intact piglets.

In order to assess pulmonary endothelial permeability to sodium in the immature lung, 15 multiple indicator dilution curves were done in eight intact piglets. An indicator bolus consisting of T-1824, 22Na, and tritiated water (THO) was delivered into the right atrium and blood was sampled from the aorta. The concentration of sodium, expressed as a fraction of the quantity injected and of the corresponding fractional concentration of T-1824, was averaged for the samples prior to recirculation. The permeability-surface area product calculated from these data is 2.0 X 10(-5) cm sec-1, and is virtually identical with the value reported elsewhere for adult dogs. Extravascular lung water obtained from the triated water and T-1824 curves averaged 64%, whereas that obtained from the 22Na and T-1824 curves averaged 23% of blood-free lung water.

Animals

Ventricular paired pacing to control rapid ventricular heart rate following open heart surgery. Observations on ectopic automaticity. Report of a case in a four-month-old patient.

An unusual case is presented in which an atrioventricular (A-V) junctional tachycardia at a rate of 285 beats/min developed in the immediate postoperative period following surgical repair (a Mustard procedure) of transposition of the great vessels in a four-month-old infant. With that heart rate the systolic blood pressure bacame 35-40 mm Hg and urinary output ceased. Ventricular paired pacing was employed successfully to halve the mechanically effective ventricular rate. This resulted in a clinically effective blood pressure and return of normal urinary output. The clinical course of the A-V junctional tachycardia, plus its response to several interventions, suggested that the mechanism of the A-V junctional tachycardia was automatic rather than re-entrant. The study demonstrates that ventricular paired pacing for the control of cardiac arrhythmias is a useful clinical technique in selected cases.

Atrioventricular Node