Averill A. Liebow

Bronchial and Arterial Anomalies with Drainage of the Right Lung into the Inferior Vena Cava

Three cases of anomalous pulmonary venous return to the inferior vena cava are presented and 18 previously reported cases are also analyzed. The clinical, radiographic, circulatory and pulmonary function, and anatomic features are carefully detailed. In particular, associated vascular and bronchial anomalies in the lungs were found by preparation of vinylite casts of the pulmonary vessels and bronchial casts; they are of great significance in planning and executing surgical therapy.

Absorption of Intact Protein Molecules across the Pulmonary Air-Tissue Barrier

The majority of heterologous serum albumin and globulin molecules introduced into the pulmonary alveoli of dogs are absorbed into the circulatory system antigenically intact. This function of the alveoli has both physiologic and pathologic importance.

The Effects of Increased Intracranial Pressure on the Pulmonary Circulation in Relation to Pulmonary Edema

Sudden elevation of intracranial pressure raises not only the systemic but also the pulmonary intravascular pressures, on occasion, sufficiently to result in pulmonary edema. At least two mechanisms are concerned, that of bradycardia, and that of left ventricular failure. Evidence is presented that interruption of vagal inflow temporarily abolishes the first mechanism. These observations are considered in relation to the clinical problem of head injury.

Renal Adaptation to Anemia

Renal adaptation to anemia was studied in dogs that had been bled repeatedly during a week to produce hematocrit values of between 12 and 21%. Total renal blood flow was unaltered despite a significant increase in cardiac output. Total renal oxygen consumption was within normal limits, but the Po2 of cortical tissue was significantly reduced. Glomerular filtration rate and therefore filtered sodium load were reduced. These alterations were interpreted as resulting from preglomerular vasoconstriction together with a decrease in postglomerular vascular resistance, the latter perhaps a consequence chiefly of the diminished blood viscosity. Sodium reabsorption in relation to filtered sodium load was unimpaired in anemic animals; actually the sodium excretion factor was lower than in normal animals. It is concluded that the maintenance of normal renal function in the anemic animal is obtained by a decrease in work load (i.e. reduced glomerular filtration rate) and more efficient oxygen extraction related to increased blood tissue Po2 gradient. Increased titers of erythropoiesis-stimulating substance could be demonstrated in these anemic animals. It is suggested that the low cortical tissue Po2 is responsible for the release of this factor.

Hormonal control of collateral circulation

The possible regulatory effects of growth hormone and of cortisone on the development of pulmonary collateral vessels after ligation of one pulmonary artery were investigated in the rat. The weights of the animals were regulated so that they did not differ significantly in the control and experimental groups at the end of the experiment. The extent of the collateral circulation was judged by visual inspection and by weighing the casts. Animals injected with cortisone acetate intramuscularly in doses of 5 mg daily for two weeks and then maintained on an average dose of 15 mg weekly, had less development of collateral circulation at four and eight weeks than did controls. Animals injected with growth hormone in doses of 0.1 mg daily, had significantly larger collaterals than did controls at eight but not at four weeks, as determined by the visual ranking method. These results indicate 1) that there can be chemical control of collateral circulation, and 2) that cortisone and growth hormone can influence the development of collateral vessels in part by mechanisms other than an effect on body weight.

Effect of Macromolecular Material from Chick Embryos on Growth Rate of Mouse Heart Fibroblast Cultures.

Summary It is shown that a macromolecular fraction isolated from chick embryo extracts by differential high-speed centrifugation essentially according to Claude, exerts a distinct growth-stimulating effect on cultures of mouse heart fibroblasts. The writers wish to acknowledge the technical assistance of Miss E. Carter and of Mr. H. Nelson in these experiments.

Application of induced pulmonary arterial collateral circulation as collateral supply to the heart.

Summary When adhesions are created between the heart and a lung the pulmonary artery of which has been ligated, abundant large connections develop between the coronary arteries and vastly expanded bronchial arteries. The efficiency of these connecting vessels as collateral blood supply to the heart is under investigation.

Renal hemodynamics and oxygen consumption in experimental chronic hypoxia

Abstract Chronic hypoxia and polycythemia were produced in dogs by anastomosing the inferior vena cava end-to-end to the right inferior pulmonary vein, diverting all inferior caval blood flow into the left atrium. The resultant arterial desaturation ranged from 67%, 2 to 7 days after shunting, to 80% 8 months later. A progressive increase in hematocrit and left heart output after the right-to-left shunt was noted, resulting in increased oxygen transport with the passage of time. An experimental technique was developed for monitoring renal hemodynamics which was relatively atraumatic, not requiring a laparotomy or other major surgery. Utilizing this technique, it was found that chronic hypoxia increased renal blood flow and decreased renal vascular resistance. The data thus imply renal vasodilatation or opening of arteriovenous shunts when the kidney is chronically exposed to a low arterial pO2 (33–54 mm. Hg). In this range of arterial oxygen tension, renal O2 consumption did not differ significantly from normal, and there was no evidence of conversion from aerobic to anaerobic renal metabolism. Although production of chronic hypoxemia resulted in significant erythropoiesis (hematocrit 55% 8 months after operation), no enlargement of the kidneys by weight was noted at the completion of the study.

Polyethylene Plastic Needle Guides for Angiostomy.

Summary The construction of a polyethylene plastic angiostomy cannula is described. This cannula has many advantages for manometry of otherwise inaccessible structures in the intact animal.