Morton Galdston

Surface properties and hysteresis of dipalmitoyllecithin in relation to the alveolar lining layer

Abstract 1. 1. Investigations using surface pressure and surface potential measurements and observations of changes in the film state were undertaken to account for the factors which determine the surface properties and hysteresis of l -α-dipalmitoyllecithin films which have been reported to resemble lung extract films and to be mainly responsible for the capacity of the alveolar lining to maintain lung stability. 2. 2. When a film of l -α-dipalmitoyllecithin is compressed intermittently to an area short of film collapse, hysteresis increases with the extent of film compression and it is associated with parallel changes in surface pressure and surface potential and is reproducible in successive cycles. Lecithin films are in the liquid state below surface pressure of 35 dynes/cm, in the gel state between 35 and 40 dynes/cm and in the solid state above 40 dynes/cm. 3. 3. When compression is continued beyond film collapse (about 44 dynes/cm) surface pressure rises sharply unaccompanied by a parallel increase in surface potential. Here hysteresis results from film solidification and loss of material from the surface and probable entrance of saline solution into gaps in the film during expansion. 4. 4. Initially highly compressed lecithin films formed by adding large quantities to the surface exhibit an earlier onset of film solidification, and of displacement of material from the surface during compression, and therefore, a greater degree of hysteresis, than initially fully expanded films. 5. 5. If the alveolar lining layer responds to compression and expansion during respiration as a l -α-dipalmitoyllecithin film responds in a film balance, then it is stable during expiration only when surface tension is above 32−28 dynes/cm. Below this surface tension level, the lining layer would collapse and the material displaced would have to return to the alveolar surface or be replenished during inspiration to maintain a healthy alveolar lining layer. The studies reported herein indicate that lecithin displaced from the surface during compression is not restored during expansion.

Elastase-Like, Esteroprotease Activity in Human and Rabbit Alveolar Macrophage Granules

Summary Human alveolar macrophages were collected postmortem and their granules were analyzed for acid phosphatase, beta-glucuronidase and elastase-like esteroprotease. Alveolar macrophages from BCG-vaccinated rabbits were also studied. The alveolar macrophage granule preparations showed satisfactory levels of acid hydrolases but were nevertheless low in elastase-like esteroprotease activity when compared to human polymorphonuclear leukocyte granules. Part of the reduction in enzyme may be accounted for by differences in lysosomal content of the granule preparations from these two cell types. Human alveolar macrophage granules showed elastinolytic activity commensurate with their esterolytic activity against t-BOC-l-alanine p-nitrophenol. The macrophage alanine-p-nitrophenyl esterase was not affected by an endogenous inhibitor of the leukocyte esterase. The possible role of these enzymes in the pathogenesis of emphysema remains to be explored.

Isolation and characterization of a lung lipoprotein surfactant

Abstract A highly surface active lipoprotein fraction was isolated in the sediment of cell-free lung wash of excised rabbit lung by a relatively simple centrifugation technique (50,000 × g, 7 C; twice for one hour, with removal of the supernatant). Based on immunology and disc electrophoresis studies we believe the lipoprotein is indigenous to lung. It consists of about 60% lipid (lecithin) and 40% protein by weight. Of the lipid, about 90% is phospholipid and 10% non-phospholipid. By gas-liquid chromatography, the total fatty acids of the lipid moiety were found to be equally distributed among saturated and unsaturated acids. In different preparations, there was a consistent mobility of bands on disc electrophoresis, and, in addition, we obtained reproducible surface pressure-area and surface potential-area curves, relating area occupied by known quantities of lipoprotein (M2/mg), spread in a 0.1% solution of amyl alcohol. The findings indicate uniformity of the lipoprotein extracted. The lipoprotein monolayers showed no hysteresis in their force-area and surface potential-area curves and remained in the liquid state. Hysteresis occurred after injection of an aliquot of a 0.9% saline minced lung extract under lipoprotein monolayers. It appears that hysteresis of films of lung extract solution is related to penetration and desorption of soluble species during expansion and compression, respectively.

Lipid-Protein Association in Lung Surfactant

We investigated the nature of the lipid-protein association and the role of the protein moiety in a highly surface active lipoprotein fraction we isolated from cell-free rabbit lung wash and also compared the surface properties of dipalmitoyl lecithin, generally believed chiefly responsible for the surface properties of lung surfactant, with those of the lipoprotein fraction.

Ambulance notes of a Bellevue Hospital intern: May 1938.

In 1938, as a New York University/Bellevue Hospital intern, I recorded notes on the 384 cases I saw during my 1-month ambulance duty. Although I intended to use them to follow up the clinical course of patients I admitted to Bellevue, the long hours and pressure of work made this ambitious goal unachievable. Sixty years later, after retirement from academic medicine and medical practice at New York University School of Medicine, I found the long-lost notes among my papers. They are of historic interest since they provide insight into aspects of primary and emergency medicine of the era when the therapeutic efficacy of the sulfanilamide class of agents was under investigation, a unique view of the life of an intern just before interns were replaced on ambulances by technicians, and a glimpse of the surprising character of several neighborhoods of pre-World War II Manhattan. The notes also provide the basis for a current analysis of case incidence and treatment by disease category. A description of the confluence of social, economic, and political forces that led to the establishment of the Bellevue Hospital Ambulance Service, the first such urban service in the world, is included.