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Biomedical subjects

D L Levin

Publications and source records attributed to D L Levin.

At least 91 records · Page 5Linked to original sources
PubMed1978

Morphologic analysis of the pulmonary vascular bed in congenital left-sided diaphragmatic hernia.

The contribution of an abnormal pulmonary vascular bed to right-to-left shunting in patients with congenital left-sided diaphragmatic hernia and alveolar hypoplasia has not been defined. In three infants we analyzed lungs fixed by perfusion. Left lung volumes (ml/kg birth weight) were 1.7, 6.5 and 4.0 respectively (control = 11.7) and right lung volumes 5.7, 11.7 and 9.8 respectively (control = 14.3). Serial sections were prepared and fifth generation (resistance) vessels identified. Compared to control the medial widths were increased in all lungs and the medial width/external diameter ratios were increased in the left lungs of two patients and the right lung of one. The m/d ratio in the left lung was greater than that in the right lung in two of the three patients. There were fewer pulmonary vessels/cm2 lung tissue in the study lungs than in the control lung, and there were significantly fewer pulmonary vessels/cm2 lung tissue in the left than in the right lung in two of the three patients. Although there was increased smooth muscle in resistance vessels, intravenous therapy with tolazoline HCl did not improve systemic oxygenation. We conclude that this was probably due to the decreased total size of the pulmonary vascular bed and the decreased number of pulmonary vessels per unit lung tissue, causing a fixed high pulmonary vascular resistance.

Female↗
PubMed1978

Morphologic analysis of the pulmonary vascular bed in infants exposed in utero to prostaglandin synthetase inhibitors.

Since the effects of prostaglandin synthetase inhibitors on the developing human fetal pulmonary vasculature are unknown, we studied the lungs of two infants, one whose mother took salicylates and the other whose mother took indomethacin during pregnancy. Lungs were fixed by perfusion and fifth generation (resistance) vessels identified. The infant with chronic exposure to aspirin had premature constriction of the ductus arteriosus, tricuspid insufficiency, increased pulmonary arterial medial width/external diameter ratio due to increased smooth muscle, and a decreased number of pulmonary vessels/cm2 lung tissue. The infant with short-term exposure to indomethacin had hypoxemia, increased pulmonary arterial m/d ratio due to increased smooth muscle, and a normal number of pulmonary vessels/cm2 lung tissue. These abnormalities may be due to the effects of prostaglandin synthetase inhibitor drugs on the ductus arteriosus and/or the pulmonary vessels of the human fetus.

Adult↗
PubMed1977

d-Transposition of the great vessels in the neonate. A clinical diagnosis.

We reviewed the records of 66 neonatal patients with d-transposition of the great vessels (d-TGV) admitted to our institution. The initial history, physical examination by the cardiologist, chest rotengenogram, ECG, hemoglobin level, and hematocrit value were analyzed. Although all patients all patients were cyanotic and 65% were tachypneic, other signs of a major congenital cardiac anomaly were usually absent. The number of clinical signs (poor general status, cyanosis, respiratory distress, S2 increased and single, murmur, classical chest roentgenogram, abnormal ECG) present in each patient was three or less in 41%, only 13.5% had more than five signs.

Aorta↗
PubMed1976

The cancer mortality scare. Problems of estimation using monthly data.

Considerable attention has been given recently to an apparent 5.2% rise in cancer mortality, based on data for the first seven months of 1975 as reported to the National Center for Health Statistics (NCHS). Later data disclosed that the rise in crude total cancer mortality, while greater than in any recent year, is less than half of the 5.2% originally reported, and the rise in age-adjusted total cancer mortality, while less than 1%, is also higher than the average annual increase from 1968 to 1974. The Monthly Vital Statistics Report provides death rates not standardized for age, race, and sex, and does not include information for specific cancer sites. Therefore, although information in the Monthly Vital Statistics Report is useful for detecting sudden increases in mortality from acute epidemics, it is not appropriate for forecasting trends in cancer mortality.

Humans↗
PubMed1976

Persistent pulmonary hypertension of the newborn infant.

Persistent pulmonary hypertension of the newborn infant can be difficult to distinguish from other cardiopulmonary causes of cyanosis during the newborn period. Infants with PPHN have cyanosis, tachypnea, acidemia, normal pulmonary parenchymal markings on the chest radiography, and anatomically normal hearts. We have identified and treated 11 infants and have noted several signs and symptoms not previously emphasized. These are cineangiocardiographic evidence of atrioventricular valve insufficiency in association with systolic murmurs and slow ventricular emptying, apnea, hypocalcemia, only a small rise in abdominal aortic blood oxygen tension during breathing of 100% oxygen, and no response to continuous positive airway pressure. Right-to-left shunting through the patent ductus arteriosus was documented in nine infants: in all six of those in whom simultaneous temporal and abdominal aortic blood oxygen tension measurements were made; in three by means of cardiac catheterization. Ten infants survived after variable courses and treatments which makes it difficult to ascribe improvement to any one therapy. The distinct increase in blood oxygen tension with tolazoline HCl and curare in some instances is discussed.

Cyanosis↗
PubMed1976

Effects of alpha-adrenergic blockade on sodium excretion in normal and chronic salt retaining dogs.

The alpha-adrenergic blocking agent phenoxybenzamine (PBA) was administered intravenously (10 mug kg-1 min-1) during a steady state water diuresis under pentothal anesthesia to six normal dogs, six dogs with chronic throacic inferior vena cava constriction and ascites (caval dogs) and seven dogs chronically salt depleted by sodium restriction and furosemide administration. In normal dogs urinary sodium excretion increased significantly from 265+/56 (SEM) to 370+/65 muequiv./min, whereas no increase in sodium excretion was noted in either caval dogs or salt depleted animals after PBA. In all three groups urine volume, fractional free water clearance and distalsodium load did not change significantly. In normal dogs, tubular sodium reabsorption decreased significantly from 73.4+/2.8% to 63.1+/4.0%, whereas no change was noted in caval or salt depleted dogs. Blood pressure and renal hemodynamics were not significantly altered by PBA administration in any group. These data demonstrate a natriuretic effect of alpha-adrenergic blockade in normal dogs with the major effect in the water clearing segment of the nephron. The absence of any effect in chronic caval or salt depleted dogs suggests that increased alpha-adrenergic activity does not play a significant role in the sodium retention of these animals.

Adrenergic alpha-Antagonists↗
PubMed1976

Morphological development of the pulmonary vascular bed in fetal lambs.

The morphological development that accompanies increasing pulmonary blood flow and decreasing pulmonary vascular resistance with advancing gestational age has not been delineated. To study this point we developed a method of comparing pulmonary arterial vessels of the same generations in fetal lambs. Pulmonary arteries were perfused with glutaraldehyde solution at pressures appropriate for gestational age and then injected with an India ink-gelatin-Micropaque mixture. Using the dissecting microscope and serially prepared sections we studied successively smaller generations of arteries. We assessed the medial width/external diameter ratio in a total of 825 vessels from six fetal lambs of 85 to 140 days gestation. In fifth generation, or resistance vessels, this ratio remained constant over the gestational period studied (N = 529, Y = 0.16, slope = 0.0003). We measured the volume of 17-34 randomly selected sections from each of the six fetuses, counted the total number of fifth and sixth generation vessels in these sections, and calculated the total number of these vessels per right lung. This number increased from 0.10 X 10(6) to 4.08 X 10(6) with increasing gestational age. The number of vessels per unit volume increased from 7.2 X 10(3)/ml to 61.8 X 10(3)/ml or right lung over this gestational period. The results indicate that increased pulmonary blood flow and decreased pulmonary vascular resistance with advancing gestation are due to an increase in the total number of vessels and increased vasomotor reactivity is related to an increase in the total amount of smooth muscle while the thickness of muscle in individual vessels remains constant.

Animals↗
PubMed1976

Evidence for enhanced distal tubule sodium reabsorption in chronic salt-depleted dogs.

In order to assess the renal tubular site(s) at which sodium reabsorption is enhanced in chronic sodium-depletion, seven normal dogs, six salt-depleted dogs, and three normal dogs receiving aldosterone were studied during a steady-state water diuresis under Pentothal anesthesia and during progressive hypotonic saline diuresis. For both maintenance of the water diuresis and progressive hypotonic saline diuresis 0.45% NaCl was used. During the steady state water diuresis delivery of sodium to the diluting segment of the nephron as approximated by solute-free water clearance + sodium clearance/glomerular filtration rate (CH2O + CNa/GFR) was significantly lower in salt-depleted dogs compared to normal dogs with or without aldosterone. During progressive hypotonic saline infusion fractional free water excretion (CH2O/GFR) was similar in all three groups as CH2O + CNa/GFR increased up to 12-14 ml/min-100 ml GFR. Thereafter, CH2O/GFR continued to rise in virtually a straight line in salt-depleted dogs but leveled off in normal dogs with or without aldosterone. These data demonstrate that enhanced sodium reabsorption in the diluting segment of the nephron is an important determinant of the renal sodium retention in chronic extracellular volume contraction in dogs in addition to confirming the presence of increased proximal tubule sodium reabsorption in these animals.

Aldosterone↗
PubMed1976

The effect of the plasma bicarbonate level on proximal tubule sodium reabsorption in NH4Cl-loaded dogs.

In an attempt to examine the effects of mild and severe chronic metabolic acidosis on proximal tubule sodium reabsorption, 6 dogs were given 10 mEq. per kilogram per day and 5 dogs were given 20mEq. per kilogram per day of ammonium chloride for 3 days and compared to 12 normal dogs during a steady-state water diuresis and following the administration of ethacrynic acid (EA) intravenously (2 mg. per kilogram) utilizing standard clearance methodology, In the severely acidotic group (pH decrease is greater tthan 0.2) plasma pH was 7.08 +/- 0.06 and plasma bicarbonate was 6.3 +/- 1.0 Eq. per liter compared to a pH of 7.33 +/-0.02 and bicarbonate of 13.4 +/- 0.7 in mild acidosis (pH decrease is less than 0.2). During a steady-state water diuresis urine flow was 14.2 +/- 0.9 in severely acidotic compared to 10.5 +/-0.7 ml. per minute per 100 ml. glomerular filtration rate (GFR) in normal dogs (p is less than 0.01). Following EA sodium clearance increased 38.4 +/- 3.5 in severely acidotic dogs and 27.6 +/- 2.0 ml. per minute per 100 ml. GFR in normal dogs (p is less than 0.02). In mild acidosis, steady-state fractional urine flow and the increase in fractional sodium clearance following EA were not significantly different than normal dogs. We conclude that chronic metabolic acidosis leads to an increase in distal solute load and enhanced natriuretic effect of EA secondary to a decrease in proximal tubule sodium reabsorption which may be dependent upon the degree of reduction in the plasma bicarbonate level.

Acidosis↗
PubMed1975

Congenital heart disease in low birth weight infants.

In this study of low birth weight infants (less than 2500 g), we compared the birth weight distribution of patients with patent ductus arteriosus associated with prematurity with that of patients having congenital heart disease other than patent ductus arteriosus. Among 1436 low birth weight infants 37 infants had congenital heart disease other than patent ductus arteriosus and 198 had isolated ductus arteriosus. Infants with congenital heart disease had a mean birth weight of 2018 grams (standard deviation = 370 g) which was significantly greater than that of infants with patent ductus arteriosus. Four of the 37 infants with congenital heart disease other than ductus arteriosus were among 1150 low birth weight infants born in this institution, an incidence of 3.5/1000 live low birth weight infants. Seventy-eight of the 198 infants with patent ductus arteriosus were among 1150 low birth weight infants born in this institution, an incidence of 70/1000 live low birth weight infants. Twenty-one of the 37 infants with congenital heart disease were of appropriate weight for gestational age and 16 were small for gestational age.

Aorta↗
PubMed1975

Cor pulmonale secondary to upper airway obstruction. Cardiac catheterization, immunologic, and psychometric evaluation in nine patients.

Previous reports of cor pulmonale due to upper airway obstruction have not noted that chronic hypoxemia due to alveolar hypoventilation can lead to left as well as right ventricular failure in these patients. We found elevated left ventricular end-diastolic pressure in four of five patients. Although these patients have frequent respiratory infections, no investigation of their immune status has previously been reported. We performed such investigations but could not demonstrate an immunologic deficiency. Although nine of 44 patients previously reported were mentally retarded, no psychometric data were available. We studied five patients but could not determine the role of mental subnormality in this syndrome. Diagnosis of this syndrome should be suspected when clinical and roentgenographic findings of biventricular heart failure are associated with right ventricular hypertrophy on electrocardiogram. The diagnosis of alveolar hypoventilation is confirmed by blood gas findings and examination of the upper airways. Surgical removal of obstructive tissue reverses the cardiac involvement.

Adenoidectomy↗
PubMed1975

Persistence of the fetal cardiopulmonary circulatory pathway: survival of an infant after a prolonged course;.

The first case of "idiopathic" persistence of the fetal cardiopulmonary circulatory pathway with survival after a prolonged course is documented by serial cardiac catheterizations. All previously reported infants have either markedly improved within the first week of life or subsequently died. This entity has been described in term infants with prenatal or perinatal distress who present with tachypnea and cyanosis from birth. The chest radiograph is remarkable for the absence of pulmonary parenchymal pathology and the hemoglobin and hematocrit are normal. Blood gas determinations indicate hypoxia and acidosis with or without hypercarbia. Cardiac catheterization and angiography reveal an anatomically normal heart with severe pulmonary hypertension, left ventricular pressure lower than right ventricular pressure, and right-to-left venoarterial shunting through the fetal channels (atrial and or ductal levels). It is postulated that this entity may result from antenatal factors that affect the pulmonary vasculature and its subsequent adjustment to extrauterine life. These factors may include abnormal intrauterine stress resulting in excessive hypertrophy of the pulmonary arteriolar smooth muscle, or abnormal pulmonary vascular responsiveness to the usual vasoactive stimuli before or after birth, or an immature or dysfunctioning enzyme system necessary for the normal decrease in pulmonary artery pressure.

Angiography↗
PubMed1975

Acute renal failure secondary to ureteral fungus ball obstruction in a patient with reversible deficient cell-mediated immunity.

A patient with a single functioning kidney and anuria due to ureteropelvic obstruction by a Candida fungus ball is described. During treatment with amphotericin B administered via a nephrostomy tube the drug was not detected in the serum, indicating that absorption from urothelium was not significant. Immunological studies demonstrated a lack of cell-mediated immunity which was probably brought about by a long course of prednisone and later restored when this drug was discontinued. This immunosuppression was evident even with a relatively small dosage of prednisone (5 mg daily). The literature concerning renal candidiasis and predisposing factors is reviewed.

Acute Kidney Injury↗