Leukocyte involvement in pulmonary localization of blood-borne microparticulates: relationship to altered lung fluid balance.

The lung lymph fistula preparation in sheep was used to study the influence of localization of blood-borne foreign microparticulates in the lung on lymph flow (Qlym); lymph-to-plasma total protein concentration ratios (L/P); pulmonary transvascular protein clearance (Qlym X L/P); and pulmonary hemodynamics. Test particles small enough to readily pass through capillary beds were infused intraarterially to avoid acute lung vascular injury by macroembolism. In sheep, tissue distribution patterns demonstrated that by 15 min after intravenous infusion of the gelatinized reticuloendothelial (RE) test lipid emulsion (0.8-1.0 micron) or gelatinized colloidal carbon (250 A), 30-35% of the injected particle dose localized in the lung, with approximately 15-22% in RE cell-rich organs such as the liver. Particle infusion resulted in an acute neutropenia in the absence of a decline in platelets. Electron microscopy revealed that the increased particulate localization in the lung reflected particle uptake by marginated phagocytic cells as well as the presence of microaggregates within the vascular space. Lung localization of both particulates resulted in approximately a 200-300% increase in both lymph flow and transvascular protein clearance. The hemodynamic response coupled with the pattern of transvascular protein clearance in relationship to lymph flow suggests that the alterations in fluid and protein flux were due to both an increase in microvascular pressure as well as an increase in lung vascular permeability. Marginated phagocytic cells which rapidly ingest the blood-borne foreign test particles may contribute to the altered lung fluid balance seen with the entrance of foreign or abnormal microparticulates in the blood.

The relationship of fatty acid composition and surface activity of lung extracts.

Male weanling rats were fed fat-free diets supplemented with 4% (w/w) safflower oil (control) or 4% tripalmitin (essential fatty acid (EFA) deficient) for 14 weeks. Whereas the amount of lecithin in lung lavage material remained unchanged, lung lavage lecithin from EFA-deficient rats contained significantly less palmitic acid (61.4 +/- 2.0% vs. 77.4 +/- 5.8%, P less than 0.01) than that from controls. Surface tension vs. area hysteresis loops were obtained for total lipid extracts (TLE) of lung lavage fluid, intra- and extra-cellular lipoprotein fractions (IBI and IBE) and lipid extracts of those lipoprotein fractions (LBI and LBE). A significant increase in minimal surface tension (gammamin) was found for all samples obtained from EFA-deficient rats as compared to controls. Refeeding of diets containing safflower oil for 7-14 days reversed these changes. Air pressure-volume curves on degassed, excised lungs indicated that greater pressure is required to maintain a given lung volume in EFA-deficient rats. These results support the hypothesis that the fatty acid composition of pulmonary surfactant lecithins is a major determinant of the surface activity of lung extracts.

Alterations in phosphatidylcholine species and their reversal in pulmonary surfactant during essential fatty-acid deficiency.

Previous studies (Kyriakides, E.C., Beeler, D.A. and Balint, J.A. (1974) Clin. Res. 22, 717a, and Burnell, J.M. and Balint, J.A. (1975) Fed. Proc. 34, 426) have indicated that essential fatty-acid deficiency in rats resulted in significant reduction of palmitate content of lung tissue and lavage phosphatidylcholines. Experiments were, therefore, undertaken to confirm and further characterize these changes and to examine the reversal of these alterations when essential fatty acid deficient rats were fed fat-free diets supplemented with linoleate for 1-14 days. Analysis of the fatty acid composition of liver lipids was used to confirm the presence of essential fatty-acid deficiency in rats that were fed a fat-free diet supplemented with 4% by weight of tripalmitoylglycerol for 14 weeks. Phosphatidylcholines from lung tissue and lavage fluid of essential fatty-acid deficient rats contained significantly less palmitate and significantly more palmitoleate and oleate than those rats receiving linoleate. These changes in fatty acid composition were reflected in a significant reduction of disaturated phosphatidylcholines (predominantly dipalmitoyl) in lung tissue and lavage fluid from essential fatty-acid deficient rats, while the total phosphatidylcholine content remained unchanged. On feeding the diet containing linoleate to the deficient rats, a reversal of these changes began after one day and was nearly complete by 7-14 days.

Cellular proliferation and renewal in the various zones of the hamster epididymis after colchicine administration.

Cellular proliferation was examined in the various regions of the excurrent ducts of the reproductive system of the male golden hamster after colchicine administration. Each of the two zones of the ductuli efferentes displayed only infrequent mitotic figures. Similarly, the basal cell population of the epididymis as well as the epithelium of the vas deferens exhibited too few mitotic figures to allow meaningful evaluation of cellular proliferation. The following observations were reported. 1. The principal cells of the entire epididymis are characterized by a singular diurnal cycle of proliferative activity reaching its maximum about 3 P.M. and its nadir about 9 A.M. 2. A circadian rhythm of cell division is also found in the principal cells of each of the six zones of the epididymis, although the time of maximal activity may vary from zone to zone. 3. The most actively proliferating region of the excurrent duct system is zone 3 of the epididymis, whereas the least active region is the ductuli efferentes. 4. The renewal rates of the principal cells vary considerably at various points along the excurrent duct system, ranging from cells which renew themselves as many as 10 times to cells which fail to renew themselves at all during the normal life-span of the animal.