Bacillus Calmette-Guérin-stimulated neutrophils release chemotaxins for monocytes in rabbit pleural spaces and in vitro

Macrophage inflammatory protein-1alpha C-C chemokine in parapneumonic pleural effusions

Parapneumonic pleural effusions are associated with the presence of a variety of inflammatory cells whose influx into the pleural space is attributed to the presence of inflammatory cytokines. Macrophage inflammatory protein-1alpha (MIP-1alpha), an important mononuclear chemokine, plays a critical role in pulmonary parenchymal inflammatory disease, but its role in the recruitment and activation of mononuclear phagocytes in the pleural space is unknown. In this study we demonstrate that complicated parapneumonic pleural effusions (empyema) and uncomplicated parapneumonic pleural effusions contain significantly (P < .001) higher levels of MIP-1alpha with higher numbers of mononuclear cells when compared with effusions resulting from malignancy and congestive heart failure. The MIP- 1alpha was biologically active and contributed 43% and 37% of the mononuclear chemotactic activity of complicated and uncomplicated parapneumonic pleural fluids, respectively. In vitro, human mesothelial cells, when stimulated with interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), or bacterial lipopolysaccharide (LPS), produced MIP-1alpha. Northern blot analysis confirmed that both endogenous (IL-1beta or TNF-alpha) and exogenous (LPS) factors induce MIP-1alpha expression in mesothelial cells. Supernatants from activated mesothelial cells demonstrated chemotactic activity for mononuclear cells. This activity was blocked by MIP-1alpha antibody, indicating that the MIP-1alpha released was biologically active. We conclude that in parapneumonic pleural effusions, MIP-1alpha plays a major but not exclusive role in the recruitment of mononuclear leukocytes from the vascular compartment to the pleural space, and pleural mesothelial cells by production of MIP-1alpha actively participate in this process.

Talc-induced expression of C-C and C-X-C chemokines and intercellular adhesion molecule-1 in mesothelial cells

Treatment of symptomatic carcinomatous pleural effusions is primarily directed at local palliation with a wide variety of sclerosing agents, of which talc is considered to be the most successful. The mechanism whereby talc achieves this effect is unknown. The objective of this study was to investigate whether talc stimulates pleural mesothelial cells (PMC) to release C-X-C and/or C-C chemokines and express adhesion molecules that initiate and amplify the inflammatory process in the pleural space. When PMC were challenged with talc in vitro, interleukin-8 (IL-8) and monocyte chemotactic protein-1 (MCP-1) levels were increased (p < 0.001) both at the protein and the mRNA level as compared with unstimulated cultures. Talc-stimulated PMC culture supernatant showed chemotactic activity for neutrophils and monocytes. The chemotactic activity of PMC culture supernatant was blocked by 44.2% with IL-8-specific antibody and by 55.7% with MCP-1-specific antibody, demonstrating that PMC-derived chemokines are bioactive. Talc also enhanced intercellular adhesion molecule-1 (ICAM-1) expression in PMC. The data demonstrate that talc stimulates PMC to release chemokines and express adhesion molecules that may play a critical role in pleurodesis.

Mechanisms of cell accumulation induced by Mycobacterium bovis BCG

Mycobacteria, specially Mycobacterium tuberculosis are among the micro-organisms that are increasing dramatically the number of infections with death, all over the world. A great number of animal experimental models have been proposed to investigate the mechanisms involved in the host response against these intracellular parasites. Studies of airway infection in guinea-pigs and rabbits, as well as in mice intravenously infected with BCG have made an important contribution to our understanding of the virulence, pathogenesis and the immunology of mycobacterial infections. Although, there are few models to study the mechanisms of the initial inflammatory process induced by the first contact with the Mycobacteria, and the relevance of the acute generation of inflammatory mediators, cytokines and leukocyte infiltration to the development of the mycobacterial infection. In this work we reviewed our results obtained with a model of M. bovis BCG-induced pleurisy in mice, describing the mechanisms involved in the leukocyte influx induced by BCG at 24 hr. Different mechanisms appear to be related with the influx of neutrophils, eosinophils and mononuclear cells and distinct inflammatory mediators, cytokines and adhesion molecules are involved in the BCG-induced cell accumulation.

[Comparative study of acute and chronic forms of pleural tuberculosis]

To analyze whether a characteristic pattern distinguishes acute forms (symptoms starting no more than one week earlier) and subacute or chronic forms (symptoms lasting more than one week) of pleural tuberculosis (PT) in our practice. Retrospective analysis of 102 cases of PT diagnosed between 1986 and 1992, comparing the findings of case histories, imaging, pleural biochemistry and cytology, microbiology of sputum, pleural biopsy and fluid, anatomy and pathology studies of the biopsy specimens, course of disease, response to treatment and sequelae after one year and a half. Thirty-two patients (31.4%) had acute PT and 70 (68.6%) had chronic forms. LDH levels and the percentage of pleural nuclear polymorphism were higher in acute cases, while the concurrence of systemic involvement and lymphocytic predominance was more often seen in chronic cases. Other data analyzed were similar in both groups. No specific clinical or X-ray profiles or differences in course of disease and response to treatment distinguishes between acute and chronic forms of PT after 7 days. Only LDH levels and cytology results differentiated acute forms and, occasionally, such cases were indistinguishable from pneumonia-like effusion.

Enhanced interleukin-8 release and gene expression in macrophages after exposure to Mycobacterium tuberculosis and its components

Mycobacterium tuberculosis infection is accompanied by acute and chronic inflammatory infiltrates associated with necrotizing granulomas in lung tissue. The cellular infiltrate is characterized by inflammatory cells which include neutrophils, lymphocytes, and macrophages. In animal and in vitro models of mycobacterial infection, cytokines including tumor necrosis factor-alpha (TNF-alpha), interferon gamma (IFN-gamma), and interleukin-1 beta (IL-1 beta) participate in granulomatous inflammation. We hypothesized that interleukin-3, a potent chemoattractant for neutrophils and lymphocytes, could be released by activated alveolar macrophages after exposure to M. tuberculosis or its components and contribute to granulomatous lung inflammation. A quantitative immunoassay revealed that IL-8 protein release was significantly elevated in supernatants of macrophages and in lavage fluid obtained from patients with pulmonary tuberculosis compared to normal controls. In addition, Northern blots demonstrated striking up-regulation of IL-8 mRNA in macrophages from these patients. M. tuberculosis and its cell wall components lipoarabinomannan (LAM), lipomannan (LM), and phosphoinositolmannoside (PIM) stimulated IL-8 protein release and mRNA expression in vitro from alveolar macrophages, but deacylated LAM did not. Neutralizing antibodies to TNF-alpha and/or IL-1-alpha and beta blocked 83% of the stimulation. IL-8 synthesis and release is an early response of macrophages after phagocytosis of M. tuberculosis. Its production serves to attract both acute and chronic inflammatory cells of active infection and thus participates in the process of containment of the pathogen.

Circulating adhesion molecules in tuberculosis

Leucocyte-endothelial adhesion molecules have been implicated in the pathogenesis of inflammatory diseases. To evaluate their role as markers of disease activity in tuberculosis, we have used an antigen capture ELISA to measure the serum concentrations of circulating intercellular adhesion molecule-1 (cICAM-1), E-selectin (cE-selectin) and vascular cell adhesion molecule-1 (cVCAM-1) in 34 patients with active tuberculosis (27 with pulmonary disease and seven with lymph node disease) before the commencement of standard chemotherapy, 15 subjects who had previously completed treatment for pulmonary tuberculosis, and 27 healthy volunteers. Circulating ICAM-1 and E-selectin levels were significantly elevated in patients with active tuberculosis when compared to those with treated disease (P < or = 0.01), and healthy controls (P < 0.02). Circulating VCAM-1 was raised in patients with active or old pulmonary tuberculosis (P < 0.02 versus healthy controls) but not in those with tuberculous lymphadenitis. Significant correlations were observed between the levels of cICAM-1 and cE-selectin (p = 0.63, P = 0.0001), and between cICAM-1 and cVCAM-1 (p = 0.28, P = 0.016). Taking the mean +2 s.d. of the serum level in healthy controls as the upper limit of normal range, circulating ICAM-1 had the best discriminative power in identifying active tuberculosis, being elevated in about 80% of patients but was raised in only 6.7% of subjects with treated disease and in 3.7% of normal subjects. Our data support the possibility that three adhesion molecules may be involved in the pathogenesis of tuberculosis and cICAM-1 may be a useful marker of disease activity.

Electron microscopic analysis of the normal and the activated pleural macrophage

Despite an apparent role in pleural pathophysiology, little information is known about pleural macrophage morphology. Intrapleural tetracycline (TCN) results in pleural macrophage influx and pleural fibrosis; intrapleural carrageenan (CAR) induces macrophage influx without ensuing fibrosis. Pleural macrophages collected from normal (NL) and TCN- or CAR-exposed rabbit pleural spaces were examined with electron microscopy. Cellular size; number of microvilli; pseudopods; coated pits (CP) and coated vesicles (CV); and prevalence of golgi, rough endoplasmic reticulum (RER), and intermediate filaments (IF) were determined. The means of each variable in each group were assessed by one-way analysis of variance, with post hoc testing performed by Scheffe F test; p < or = .05 was considered significant. TCN-stimulated pleural macrophages were characterized by their small perimeters. CAR-induced pleural macrophages were marked by their large size and abundant intracellular amorphous material. They had larger perimeters, areas, and diameters than the TCN-induced or normal macrophages and thus smaller numbers of CV + CP per area. The normal pleural macrophages were characterized by more IF, microvilli, and microvilli per perimeter than either the CAR- or TCN-induced pleural macrophages. No differences between groups were found in nuclear cytoplasmic ratios, number of pseudopods, and content of golgi or of RER. The results suggest that normal pleural macrophages and TCN- and CAR-induced pleural macrophages differ morphologically and that these morphologic differences reflect functional differences.

Changes in cell population and tumor necrosis factor, interleukin-6, and interleukin-8 in malignant pleural effusions after treatment with intrapleural tetracycline

To evaluate the changes in cellular components and cytokine levels (tumor necrosis factor, interleukin-6 and IL-8) before and after intrapleural tetracycline (TC) injection, we evaluated 10 patients with malignant pleural effusion. Differential cell counts in the pleural fluid were obtained using cytocentrifuge preparations. Mononuclear cells from pleural fluid, collected before intrapleural injection of TC, on Day 4, and Days 10 to 14 after TC injection, were stimulated either with phytohemagglutinin (PHA) or PHA plus phorbol myristic acetate. The production of tumor necrosis factor (TNF) and IL-8 was measured. In addition, IL-6, IL-8, and TNF from serial collections of pleural fluid in these patients were measured by RIA or ELISA. The main inflammatory cells in pleural effusions before therapy were lymphocytes and mononuclear cells, but neutrophils predominated after TC injection. IL-6, IL-8, and TNF were markedly increased on Day 4 after TC intrapleural injection and then decreased to baseline levels on Day 14. The results suggest that TC intrapleural injection induces the release of cytokines (IL-6 and TNF), which are markers of an inflammatory response, and releases IL-8, which attracts neutrophils into the pleural space, which may be the mechanism of the sclerosing effect of TC.

Pleural macrophages differentially alter mesothelial cell growth and collagen production

Intrapleural tetracycline (TCN) results in pleural macrophage influx and pleural fibrosis; intrapleural carrageenan (CAR) induces macrophage influx without fibrosis. Because macrophage products can modulate mesothelial cell activity, we investigated the role of TCN- and CAR-induced pleural macrophages on mesothelial cell growth can collagen production. Rabbit pleural macrophages, isolated by plastic adherence 72 h after 20 mg/kg TCN or 10 mg CAR instilled intrapleurally, were cultured for 20 h. Macrophage-conditioned media (MCM) from TCN-or CAR-induce pleural macrophages (TCN MCM, CAR MCM, respectively), were added to non-confluent or confluent rat visceral pleural mesothelial cells and compared to the effects of TCN and CAR. Nonconfluent mesothelial cells were harvested 72 h later for hemacytometry cell counts. A 20-h pulse of [3H] proline (1 mu Ci, 30 Ci/mM) preceded 72-h-cell harvesting of confluent cells. Collagen content was determined in the cell fraction and cell media separately after bacterial collagenase exposure. Mesothelial cells exposed to TCN MCM were found to have decreased numbers when compared to all groups (P < 0.05) except CAR. Cell media collagen content was increased in all macrophage-conditioned-media and chemical-exposed groups compared with control, with TCN MCM having a larger increase than TCN alone (P < 0.05). We conclude that stimulated pleural macrophages release a factor(s) that alters mesothelial cell growth and collagen production and that TCN- and CAR-stimulated pleural macrophages are functionally different. These in vitro mesothelial cell alterations may be important in the genesis of TCN pleurodesis.

Migration of neutrophils from the lung into the pleural space after lung resection in humans and rabbits

The origin of neutrophils that are found in pleural effusions after pulmonary resection is unknown. We measured neutrophil counts in pleural effusion sequentially for 48 h in patients who had undergone partial resection or pneumonectomy. Additionally, we measured neutrophil counts in the pleural effusions separately from the visceral pleura and parietal pleura in rabbits. In humans, we found that the maximum neutrophil counts in pleural effusion occurred more often in the patients who underwent partial resection (11.7 +/- 6.0 x 10(4) cells/microL) than in the patients who underwent pneumonectomy (3.7 +/- 1.2 x 10(4) cells/microL). There was no difference between neutrophil counts in blood of pneumonectomy group and that of the partial resection group. In rabbits, neutrophil counts were 1.5 times greater in the pleural effusion derived from the lung than in that derived from the parietal pleura. We conclude that movement of neutrophils occurs primarily from the lung into the pleural space after lung resection in humans and rabbits.

Differential cell analysis in bronchoalveolar lavage fluid from pulmonary lesions of patients with tuberculosis

To obtain information on the cellular reactions to Mycobacterium (M) tuberculosis in the lung, we analyzed the cells in bronchoalveolar lavage (BAL) fluid from pulmonary lesions in comparison with those in BAL fluid from nonaffected regions of the lungs, and control lungs, and in peripheral blood of patients with tuberculosis. Neutrophils and lymphocytes were increased in number in BAL fluid from affected lesions of the lungs of patients with miliary tuberculosis and patients with active pulmonary tuberculosis compared with those in BAL fluid from control patients, but the number of alveolar macrophages was decreased in BAL fluid from tuberculous lesions. However, the numbers of these cells were not changed in the BAL fluid from nonaffected regions of the lungs of patients with active or inactive pulmonary tuberculosis. The numbers of lymphocytes were decreased and the numbers of monocytes were increased in peripheral blood from patients with miliary tuberculosis and with active tuberculosis, indicating inverse changes in the numbers of lymphocytes and monocytes in the peripheral blood to those in the BAL fluid of patients with tuberculosis. These results indicate characteristic redistributions of immune or inflammatory cells in response to infection with M tuberculosis and suggest that these changes are important for understanding the pathophysiology of pulmonary tuberculosis.

Sequential changes in lung injury induced by preformed immune complexes

Immune complexes formed in the airside may be involved in the early parenchymal changes in hypersensitivity pneumonitis. The present study was undertaken to compare the responses of animals after an intratracheal injection with preformed immune complexes to those of patients with acute hypersensitivity pneumonitis, with special emphasis on sequential bronchoalveolar lavage findings and the possible role of chemotactic factors in the immune complex-induced lung injury. An increased number and percentage of polymorphonuclear cells could be detected in bronchoalveolar lavage fluids of guinea pigs within 48 hr following an intratracheal injection of preformed immune complexes. Chemotactic factor activity preceded the observed increase of polymorphonuclear cells in bronchoalveolar lavage fluids, suggesting a role for chemotactic factors in the sequestration of these cells in the lung. In addition, this study confirmed the usefulness of bronchoalveolar lavage in evaluating the pulmonary findings because the changes in bronchoalveolar lavage cell populations correlated with sequential histological findings. The sequential characteristics of the involved areas were noted to be of a peribronchial or bronchiolar infiltration with polymorphonuclear cells at early stages, then alveolar sac infiltration, followed by mild infiltration of mononuclear cells into the alveolar walls. The findings suggest a possible role for chemotactic factors in the accumulation of polymorphonuclear cells, and the sequential changes of bronchoalveolar lavage and histological findings in animals are comparable to those in patients with acute hypersensitivity pneumonitis.

The relationship between pleural fluid findings and the development of pleural thickening in patients with pleural tuberculosis

The objective of the study was to determine if residual pleural thickening after treatment for pleural tuberculosis could be predicted from the pleural fluid findings at the time of the initial thoracentesis. Forty-four patients initially diagnosed as having pleural tuberculosis between January 1986 and January 1988 were separated into two groups: the 23 patients in group 1 had residual pleural disease, while the 21 patients in group 2 had no residual pleural disease after treatment for their pleural tuberculosis was completed. The clinical characteristics of the two different groups did not differ significantly, but the patients in group 1 tended to be a little sicker in that the duration of their symptoms was longer, their hemoglobin values were lower, and weight loss and cough were more frequent. There were no significant differences in the pleural fluid findings in the two different groups. The mean pleural fluid protein level was 5.40 +/- 0.58 g/dl for group 1 and 5.17 +/- 0.80 g/dl for group 2, while the mean pleural fluid glucose level was 78.6 +/- 19.5 mg/dl for group 1 and 79.5 +/- 20.1 mg/dl for group 2. The mean pleural fluid lactate dehydrogenase (LDH) level in group 1 was 593 +/- 498 IU/L, while the mean level for group 2 was 491 +/- 198 IU/L. The presence of residual pleural thickening was not related to the chemotherapeutic regimen or the performance of a therapeutic thoracentesis. From this study we conclude that approximately 50 percent of patients with pleural tuberculosis will have residual pleural thickening when their therapy is completed, but that one cannot predict which patients will have residual pleural thickening from either their clinical characteristics or their pleural fluid findings.

Leukocytes in the urine after intravesical BCG treatment for superficial bladder cancer. A flow cytofluorometric analysis

Cellular immunologic reactions occurring in the bladder after intravesical treatment with bacillus Calmette-Guérin (BCG) were investigated by flow cytofluorometric analysis of leukocytes present in the urine. Urine specimens from 11 superficial bladder cancer patients were collected before and 5, 24, 48 and 72 h after repeated BCG instillations. Monoclonal antibodies specific for granulocytes, monocytes/macrophages, and T-and B-lymphocytes were used to characterize and quantify leukocyte subpopulations. The total number of cells in urine was found to be 2- to 485-fold increased 24 h after BCG administration. The predominant cell type present was the polymorphonuclear granulocyte, probably representing a defense mechanism against mycobacteria. The main mononuclear leukocytes in urine specimens were monocytes/macrophages and T-lymphocytes, indicating an ongoing immune response in the bladder wall. Although percentages of lymphocytes were low, T- and B-cells could be identified using a selective cell measurement procedure. In conclusion, a clear increase in the numbers of granulocytes, monocytes/macrophages and T-lymphocytes in urine after intravesical BCG administration was demonstrated, indicating local activation of the immune system.

Presence of activated lymphocytes in the urine of patients with superficial bladder cancer after intravesical immunotherapy with bacillus Calmette-Guérin

To study the mode of action of intravesical bacillus Calmette-Guérin (BCG) immunotherapy in the prevention and cure of superficial bladder cancer, flow-cytofluorometric analysis of the cellular immunological reaction in the urine of patients was performed. Fresh urine-derived leucocytes were obtained from eight patients before (t0) and 24 h (t24) and 48 h (t48) after repeated intravesical BCG instillations (at least 5 instillations). For two patients urine-derived leucocytes were investigated at the first BCG instillation. The number of leucocytes in the urine was markedly increased 24 h after repeated BCG instillations, indicating a local cellular immunological reaction induced by BCG. The mean number of cells per milliliter of urine at that time was 2.9 x 10(6) +/- 3.6 x 10(6) (n = 8). These leucocytes consisted mainly of granulocytes (75 +/- 11%, n = 8). In addition monocytes/macrophages (4 +/- 2%, n = 8) and T lymphocytes were present (1 +/- 1%, n = 5). The relative increase of monocytes/macrophages in the urine after BCG application tended to be higher compared to the other leucocyte subtypes. As T lymphocytes may play an important role in the BCG-mediated anti-tumour activity, subsets of lymphocytes were further characterized at t0, t24, and t48 after repeated BCG instillations. The lymphocyte population consisted mainly of T cells (86% CD3+, t0). Most of the T cells were CD4+ (helper/inducer) and were significantly decreased at 48 h (62 +/- 9% at t0 vs 49 +/- 6% at t48). Lymphocytes partly expressed HLA-DR antigens (44%, t0). The percentage of lymphocytes with interleukin-2 (IL-2) receptors (CD25+) was significantly increased at 24 h and 48 h, compared to pre-instillation values (19 +/- 11% and 10 +/- 4% vs 3 +/- 3% respectively). Natural killer cells (CD16+ and/or CD56+) and B cells (CD19+) were less numerous (10% and 19% at t0 respectively). After the first BCG instillation the increase in the number of leucocytes in urine seemed to be less compared to the numbers after repeated BCG instillations. Lymphocytes could not be detected in the urine collected before or after the first BCG instillation. In conclusion, we demonstrated the presence of considerable numbers of leucocytes in the urine 24 h after repeated BCG instillations, i.e. shortly after immunological activation. The antigen expression of the lymphocytes suggested that they may represent the lymphocytes in the bladder wall. Expression of HLA-DR and IL-2 receptors on lymphocytes indicated activation of T cells by the intravesical BCG treatment.(ABSTRACT TRUNCATED AT 400 WORDS)

The histology of experimental pleural injury with tetracycline, empyema, and carrageenan

Models of pleural injury were established with intrapleural tetracycline, intrapleural carrageenan, and empyema in New Zealand White rabbits to evaluate histologically the pleural inflammatory response from 3 to 90 days. Both tetracycline and empyema models produced increases in the pleural connective tissue layers both above and below the fibroelastic membrane associated with angiogenesis and lymphangiogenesis. The influx of fibroblasts from the pleural surface into acellular fibrin strands formed adhesions between the visceral and the parietal pleurae. Injury to the mesothelial cell ranged from a cuboidal transition to total desquamation with the degree of mesothelial injury associated with the amount of fibrin adherence and the propensity toward fibrosis at 90 days. Intervention to promote the resolution of pleural inflammation without fibrosis should be directed toward preservation of the mesothelial surface, removal of pleural fibrin, and inhibition of fibroblast growth and chemotaxis.

Pleural mesothelial cells stimulated by asbestos release chemotactic activity for neutrophils in vitro

The development of the pleural inflammatory response to asbestos remains poorly defined. Importantly, the role of the pleural mesothelial cell in recruitment of neutrophils to the pleural space is not known. We hypothesized that rabbit pleural mesothelial cells stimulated by asbestos fibers release chemotactic factor(s) for neutrophils. Primary cultures of rabbit pleural mesothelial cells were established, and their purity verified by the presence of keratin and hyaluronic acid mucin. Mesothelial cells in serum-free media, in the presence of 30 micrograms/ml of crocidolite asbestos, released chemotaxins for neutrophils. This activity was not dependent on the type of asbestos fiber or fiber length. It was dose-dependent until 30 micrograms/ml of asbestos. The chemotactic fractions had the ability to increase both directed and random migration of neutrophils. The chemotactic activity was not present in sonicated fractions of unstimulated mesothelial cells, nor in supernates of asbestos fibers alone. Characterization of the chemotactic activity showed that it was heat stable (56 degrees C per 30 min) and sensitive to digestion with trypsin and papain. On Sephadex G-50 chromatography, it had a molecular weight between 6,000 and 9,000. Production of the chemotactic activity was inhibitable by cycloheximide. These results demonstrate that pleural mesothelial cells can actively synthesize a protein fraction with chemotactic activity for neutrophils. Production of this mesothelial cell-derived chemotactic activity for neutrophils may play an important role in the initiation of the inflammatory response of the pleura to asbestos.

Effect of inhaled leukotriene C4 on cardiopulmonary function

The changes in transcutaneous oxygen saturation (SaO2%) and airway responses to inhaled histamine and leukotriene C4 (LTC4) were examined in 10 asthmatic patients, and the effect of inhaled LTC4 (16 nmol) on cardiopulmonary hemodynamics was examined in seven nonasthmatic patients undergoing diagnostic cardiac catheterization. In asthmatic patients, LTC4 produced oxygen desaturation on two occasions. At a lower dose (2.0 nmol) LTC4 produced a marked fall in SaO2% that lasted less than 15 min and occurred in the absence of significant bronchoconstriction as measured by changes in FEV1, FEF25-75, and SGaw. At a higher cumulative dose (7 nmol), LTC4 caused prolonged oxygen desaturation with slow recovery and this was associated with significant bronchoconstriction. In contrast, histamine inhalation produced a single response with a fall in both FEV1 and SaO2% of short duration. The dose-response characteristics of LTC4 and histamine on oxygen desaturation in asthmatic patients appear to differ significantly and probably are dependent on relative sensitivities of pulmonary vascular and bronchial smooth muscle to these agonists. A single inhaled dose of LTC4 in nonasthmatic subjects produced a marked drop in PaO2 with significant increase in AaPO2, and this was associated with a mean (SEM) decrease in FEV1 of 14% (2.5) from the baseline. The mean cardiac output fell by 15% (3.4) without significant changes in blood pressure and heart rate. There was no electrocardiographic evidence of myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence for activation of a respiratory burst in the interaction of human neutrophils with Mycobacterium tuberculosis

We examined the capacity of human neutrophils to develop a respiratory burst, as monitored by superoxide release, in response to interaction with Mycobacterium tuberculosis. Serum-opsonized, heat-killed mycobacteria induced significant release of superoxide from neutrophils after 30 min of exposure, with a maximum release of 34 +/- 1.7 nmol/30 min per 5 X 10(6) neutrophils occurring with a mycobacterium/neutrophil ratio of 40:1. Similar levels of superoxide release were induced by live mycobacteria. Neutrophil superoxide production was reduced significantly with exposure to unopsonized organisms or by substitution of heat-inactivated serum for opsonization. Mycobacterial components including culture filtrate, purified protein derivative, and the cell wall polysaccharide arabinogalactan failed to induce significant release of superoxide from neutrophils. Transmission electron microscopy demonstrated that more than 90% of the neutrophils had ingested heat-killed mycobacteria concomitant with the development of respiratory burst activity. These data suggest that the presumed failure of neutrophil killing of mycobacteria cannot be attributed to a lack of phagocytosis or respiratory burst activation.