Lazaroid U-74389F attenuates phorbol ester-induced lung injury in rabbits.

We examined the effect of the antioxidant lazaroid U-74389F on acute lung injury induced in rabbits by phorbol myristate acetate (PMA). Thirty minutes after receiving either U-74389F (15 mg.kg-1 i.v.) or U-74389F vehicle, rabbits (n = 60) were given PMA (60 micrograms.kg-1 i.v.). PMA vehicle injected rabbits (n = 20) served as controls. Over a 5 h period after PMA or PMA vehicle injection, we measured arterial pH, arterial oxygen tension (Pa,O2), arterial carbon dioxide tension (Pa,CO2), and the plasma concentration of the neutrophil chemoattractant interleukin-8 (IL-8). At postmortem, lungs were inspected for macroscopic injury and examined histologically. Malondialdehyde levels were assayed in lung tissue as an index of lipid peroxidation. In bronchoalveolar lavage (BAL), total and differential cell counts, protein and IL-8 concentrations were measured. Compared to normal controls, rabbits challenged with PMA alone developed arterial acidosis, hypercapnia and hypoxaemia, accompanied by significant rise in plasma IL-8 concentration. U-74389F pretreated animals did not develop significant arterial blood gas abnormalities and had significantly lower IL-8 concentration in plasma. U-74389F did not prevent PMA-induced lipid peroxidation. However, macroscopic signs of lung injury and the degree of alveolar haemorrhage and protein extravasation were significantly less severe in pretreated rabbits than in those given PMA alone. In addition, U-74389F significantly reduced IL-8 concentration and neutrophil number in BAL. By histological assessment, 80% of lung neutrophils were localized in alveolar spaces of animals receiving PMA alone. Conversely, in U-74389F pretreated animals, 75% of neutrophils were distributed within extra-alveolar blood vessels and alveolar septa. We conclude that lazaroid U-74389F attenuates lung injury in rabbits given PMA by preventing neutrophil migration into pulmonary alveoli. This effect may, in part, be related to downregulation of IL-8 production.

Protein layer on hemodialysis membranes: a new immunohistochemistry technique.

In order to investigate the nature of the protein layer deposited on hemodialysis membranes we developed a direct immunohistochemical technique using fluoresceinated antibodies to plasma membranes. Fifteen patients on regular dialytic treatment were dialyzed with CU, HE, PAN, PS and PMMA and the dialyzers analyzed at the end of a standard dialytic session. Snap frozen sections of hollow fiber devices were treated with flourescein-isothiocyante conjugated antibodies for IgG, IgA, IgM C3c, fibrinogen, factor VIII, factor XIIIa-s, antithrombin III, fibrinogen degradation products (PDF) and plasminogen. Protein deposits were evaluated by a quantitative criteria, which evaluates the intensity of fluorescence and the area of the capillary wall occupied by this fluorescence by using an image analysis software. The coagulation cascade is activated by all membranes and similar deposits of these proteins were revealed, whereas important differences in C3c deposition were found.

Cellular expression of lymphocyte function-associated antigen-1 and intercellular adhesion molecule-1 in normal kidney structures and in renal cancer. Possible significance in immune response and in the clinicopathological correlation.

In this study we investigated the presence of lymphocyte function-associated antigen-1 (LFA-1) and intercellular adhesion molecule-1 (ICAM-1) on renal cell cancer in 16 patients who underwent nephrectomy. In all cases, normal renal tissues presented ICAM-1 on the parietal epithelial cells lining Bowman's capsule while neither the visceral epithelium nor the glomerular endothelium were stained. The epithelial proximal and distal tubular cells were stained poorly (5 +/- 3 positive tubular cross sections/mm2). No renal cells were stained by the monoclonal antibody for LFA-1. In contrast, in renal cancer tissue we found 6 cases, negative for ICAM-1 and the others positive with a mean number of positive tubular cross sections of 52 +/- 37/mm2. In 10 cases staining with LFA-1 antibody was negative, while for the other cases the mean number of positive tubular cross sections was 11 +/- 8/mm2. Our results suggest that the expression of ICAM-1 and LFA-1 on the surface of malignant cells may explain the unusual clinical aspects of renal cell carcinoma, its association with the immune system, and clarify certain aspects of immunotherapy.

PAF-induced histamine release in the isolated perfused rat kidney.

The platelet-activating factor (PAF) has been shown to stimulate the release of prostaglandins, leukotrienes and 5HT from a number of cell types. In this work we studied the effects of bolus injections of PAF on the isolated perfused rat kidney. Results showed histological damage at the proximal-tubule level and a significant histamine release.