Expression of interleukin 9 in the lungs of transgenic mice causes airway inflammation, mast cell hyperplasia, and bronchial hyperresponsiveness.

Interleukin (IL)-9, a pleiotropic cytokine produced by the Th2 subset of T lymphocytes has been proposed as product of a candidate gene responsible for asthma. Its wide range of biological functions on many cell types involved in the allergic immune response suggests a potentially important role in the complex pathogenesis of asthma. To investigate the contributions of IL-9 to airway inflammation and airway hyperresponsiveness in vivo, we created transgenic mice in which expression of the murine IL-9 cDNA was regulated by the rat Clara cell 10 protein promoter. Lung selective expression of IL-9 caused massive airway inflammation with eosinophils and lymphocytes as predominant infiltrating cell types. A striking finding was the presence of increased numbers of mast cells within the airway epithelium of IL-9-expressing mice. Other impressive pathologic changes in the airways were epithelial cell hypertrophy associated with accumulation of mucus-like material within nonciliated cells and increased subepithelial deposition of collagen. Physiologic evaluation of IL-9-expressing mice demonstrated normal baseline airway resistance and markedly increased airway hyperresponsiveness to inhaled methacholine. These findings strongly support an important role for IL-9 in the pathogenesis of asthma.

Recombinant interferon-gamma primes alveolar macrophages cultured in vitro for the release of leukotriene B4 in response to IgG stimulation.

The capacity of interferon-gamma to regulate the generation and release of leukotriene B4 (LTB4) from human alveolar macrophages of normal nonsmoking individuals was evaluated. When alveolar macrophages were incubated for 60 min with heat aggregated IgG (HAIgG), they generated and released 5.7 +/- 1.7 ng of LT B4 per 10(6) cells compared to 1.9 +/- 0.4 ng from cells incubated with buffer alone, P = 0.02. When alveolar macrophages were preincubated with interferon-gamma for 24 h before activation for 60 min with heat-aggregated IgG, the soluble IgG aggregates became a significantly more effective stimulus for LTB4 release, 17.0 +/- 3.9 ng/10(6) cells, P = 0.001, compared to cells incubated in the absence of interferon-gamma and challenged with HAIgG. Interferon-gamma did not alter the response to A23187. This effect of interferon-gamma was both time and dose dependent; it also was specific since neither interferon-alpha nor interferon-beta had a regulatory effect on the release of LTB4 from cells in response to challenge with HAIgG. Preincubation of the alveolar macrophages with interferon-gamma augmented the density of IgG1 receptors by 81.5 +/- 17.3%; neither interferon-alpha nor interferon-beta effected this parameter. Furthermore, monomeric IgG1 blocked HAIgG induced LTB4 release from alveolar macrophages primed with interferon-gamma. Therefore, at least one of the mechanisms by which interferon-gamma primes alveolar macrophages for the production and release of LTB4 in response to stimulation by aggregates of IgG is that of increasing the number of receptors for this stimulus.

Macrophages cultured in vitro release leukotriene B4 and neutrophil attractant/activation protein (interleukin 8) sequentially in response to stimulation with lipopolysaccharide and zymosan.

The capacity of lipopolysaccharide (LPS), zymosan, and calcium ionophore A23187 to induce neutrophil chemotactic activity (NCA), leukotriene B4 (LTB4), and neutrophil attractant/activation protein (NAP-1) release from human alveolar macrophages (AM) retrieved from normal nonsmokers was evaluated. LPS induced a dose-dependent release of LTB4 that began by 1 h, 4.0 +/- 3.2 ng/10(6) viable AM; peaked at 3 h, 24.7 +/- 13.5 ng/10(6) viable AM; and decreased by 24 h, 1.2 +/- 1.0 ng/10(6) viable AM (n = 8). Quantities of LTB4 in cell-free supernatants of AM stimulated with LPS were determined by reverse-phase high-performance liquid chromatography and corresponded well with results obtained by radioimmunoassay. By contrast, NAP-1 release began approximately 3-5 h after stimulation of AM with LPS, 197 +/- 192 ng/ml, and peaked at 24 h, 790 +/- 124 ng/ml. Release of NAP-1 was stimulus specific because A23187 evoked the release of LTB4 but not NAP-1, whereas LPS and zymosan induced the release of both LTB4 and NAP-1. The appearance of neutrophil chemotactic activity in supernatants of AM challenged with LPS for 3 h could be explained completely by the quantities of LTB4 present. After stimulation with LPS or zymosan for 24 h, AM had metabolized almost all generated LTB4. Preincubation of AM with nordihydroguiaretic acid (10(-4) M) completely abolished the appearance of NCA, LTB4, and NAP-1 in supernatants of AM challenged with LPS. Therefore, LPS and zymosan particles were potent stimuli of the sequential release of LTB4 and NAP-1 from AM.

Airway epithelial cell expression of interleukin-6 in transgenic mice. Uncoupling of airway inflammation and bronchial hyperreactivity.

We produced transgenic mice which overexpress human IL-6 in the airway epithelial cells. Transgenic mice develop a mononuclear cell infiltrate adjacent to large and mid-sized airways. Immunohistochemistry reveals these cells to be predominantly CD4+ cells, MHC class II+ cells, and B220+ cells. Transgenic mice and nontransgenic mice had similar baseline respiratory system resistance (0.47 +/- 0.06 vs 0.43 +/- 0.04 cmH2O/ml per s at 9 wk of age, P = NS and 0.45 +/- 0.07 vs 0.43 +/- 0.09 cmH2O/ml per s at 17 wk of age, P = NS). Transgenic mice, however, required a significantly higher log dose of methacholine to produce a 100% increase in respiratory system resistance as compared with non-transgenic littermates (1.34 +/- 0.24 vs 0.34 +/- 0.05 mg/ml, P < or = 0.01). We conclude that the expression of human IL-6 in the airways of transgenic mice results in a CD4+, MHC class II+, B220+ lymphocytic infiltrate surrounding large and mid-sized airways that does not alter basal respiratory resistance, but does diminish airway reactivity to methacholine. These findings demonstrate an uncoupling of IL-6-induced airway lymphocytic inflammation and airway hyperresponsiveness and suggest that some forms of airway inflammation may serve to restore altered airway physiology.

Respiratory syncytial virus induces interleukin-10 by human alveolar macrophages. Suppression of early cytokine production and implications for incomplete immunity.

Respiratory syncytial virus (RSV) causes repeated infections thought to be due to an ineffective immune response. We examined the hypothesis that incomplete immunity may result, in part, from RSV-infected alveolar macrophage production of IL-10 which can interfere with the production of immunoregulatory cytokines. We also assessed whether RSV induced the expression of the 2',5' oligoadenylate (2-5A)-dependent RNase L, an endoribonuclease involved in the antiviral activities of interferons. Human alveolar macrophages were exposed to medium (uninfected control), RSV, LPS, and RSV + LPS then were assessed for expression of the cytokines TNF-alpha, IL-1 beta, IL-8, IL-10, as well as 2-5A-dependent RNase L. LPS up-regulated the expression of protein and mRNA for all cytokines. RSV stimulated the protein levels of TNF-alpha, did not alter IL-1 beta, and decreased IL-8. RSV markedly stimulated protein expression of IL-10 and 2-5A-dependent RNase L. RSV had minor effects on the steady state mRNA levels of TNF-alpha, IL-1 beta, and IL-8, yet potently induced IL-10. Cells costimulated with RSV + LPS demonstrated reduced protein and mRNA levels of TNF-alpha, IL-1 beta, IL-8 but synergistically increased IL-10 levels compared to RSV- or LPS-activated cells. Kinetic analysis indicated that RSV induced a delayed and sustained increase in IL-10 transcripts. Furthermore, RSV-infected alveolar macrophage supernatants suppressed IL-1 beta and IL-8 production by LPS-stimulated alveolar macrophages as did recombinant IL-10. Anti-IL-10 neutralized these effects. These studies indicate that RSV is capable of suppressing production of early immunoregulatory cytokines through induction of IL-10 perhaps mediated by 2-5A-dependent RNase L (or other endoribonucleases) accounting for the ineffective immune response to this virus.

The impact of bronchoalveolar lavage cell analysis on clinicians' diagnostic reasoning about interstitial lung disease.

To assess the impact of bronchoalveolar lavage (BAL) on clinicians' diagnostic reasoning, we administered serial telephone questionnaires to all pulmonary physicians submitting BAL specimens to our laboratory from nonimmunocompromised patients with diffuse interstitial lung disease. Questionnaires were completed when the lavage specimens were first submitted and again after the results were reported to referring physicians. We recorded the clinicians' ordered list of likeliest diagnoses for the patient, a level of confidence in each diagnosis mentioned, and any proximate plans for further diagnostic tests. Of 78 patients in the study, information from the BAL fluid cell analysis caused clinicians to change their diagnostic thinking in 46 (59 percent). These changes were far more frequently appropriate (52 percent) than not (9 percent), and clinically impressive changes did occur but were infrequent (3 of 78 [4 percent]) in this series. Specifically, BAL permitted the unexpected diagnosis of Pneumocystis carinii in a patient not previously suspected to have acquired immune deficiency syndrome (AIDS) and appropriately encouraged clinicians to avert planned surgical biopsies in two patients subsequently found to have sarcoidosis. These findings suggest that when used to evaluate nonimmunocompromised patients, BAL fluid cell analysis can have an important impact on clinicians' diagnostic reasoning about their patients' interstitial lung diseases.

Bronchoalveolar lavage. Its safety in subjects with mild asthma.

It has been suggested that fiberoptic bronchoscopy may induce life-threatening bronchospasm in persons with asthma. The safety of bronchoscopy and bronchoalveolar lavage (BAL) with bilateral installation of 300 ml of saline solution was assessed prospectively in ten adults with mild asthma as a part of a study of the lower respiratory tract in bronchospastic disease. Asthmatic subjects had pretreatment with intravenous aminophylline prior to bronchoscopy. Pulmonary function tests were performed prior to and immediately after the procedure, and values were compared to results in 12 normal adults undergoing bronchoscopy with BAL. One subject had mild bronchospasm (the third subject) before BAL could be performed. There were no major complications in the remaining asthmatic or normal subjects. Mean forced expiratory volume in one second (FEV1) did not change significantly in either group, and the mid-flow rate at 50 percent of vital capacity (Vmax 50%) decreased significantly only in normal subjects (p = 0.002). Moreover, none of the nine asthmatic subjects completing bronchoscopy with BAL had clinically significant bronchospasm. These results suggest that elective fiberoptic bronchoscopy and BAL can be performed safely in subjects with mild asthma.

Anti-HIV-1 activity of 3'-azido-3'-deoxythymidine (AZT) in primary mononuclear phagocytes.

Conflicting data have been reported on ability of 3'-azido-3'-deoxythymidine (AZT) to protect mononuclear phagocytes from HIV-1 infection. We compared the antiviral potency of AZT in three types of primary human mononuclear phagocytes: peripheral blood monocytes, monocyte-derived macrophages (in vitro differentiated) and alveolar macrophages (in vivo differentiated). To establish highly-productive virus infection, purified cells (greater than 99%) from healthy donors were challenged with the macrophage-tropic HTLV-IIIBa-L strain at input multiplicities ranging from 0.05 to 20 TCID50 per cell. AZT (0.1 nM-10 microM) was added immediately after infection and either continued for the duration of the experiment or stopped 1-7 days after infection. The kinetics of HIV-1Ba-L replication were assessed by measuring p24 antigen production on days 4-28 post-infection. Continuous treatment with AZT reproducibly inhibited viral replication in a concentration-dependent manner in all three cell types. The IC90 of AZT was 0.04 microM in blood monocytes, 0.009 microM in monocyte-derived macrophages, and 0.0001 microM in alveolar macrophages (mean of 3-4 donors for each cell type). AZT was not cytotoxic at less than 10 microM as assessed by cell viability, cell protein, and interferon-gamma-activated H2O2-release. In experiments in which AZT treatment was stopped after infection, viral replication resumed after a lag of 7-14 days and increased exponentially toward control levels. This occurred despite initial inhibition of virus production to below the limit of p24 detection (approximately 50 pg/ml). These results indicate that AZT is a potent inhibitor of HIV-1 replication in primary mononuclear phagocytes regardless of the stage of cell differentiation, and that AZT is most active in tissue (alveolar) macrophages. AZT does not irreversibly block infection of mononuclear phagocytes, however, as viral replication resumes after removal of AZT.

Bronchoalveolar cell activation after inhalation of a bronchoconstricting agent.

Airway inflammation is thought to be an important determinant of bronchoconstriction and bronchial hyperreactivity. We have recently demonstrated that bronchoconstriction induced by an aqueous extract of cotton bracts (CBE) is associated with bronchoalveolar complement activation, release of polymorphonuclear neutrophil (PMN) chemoattractants by pulmonary cells, and increased numbers of bronchoalveolar lavage PMN's. In the present study we performed bronchoalveolar lavage (BAL) on subjects after CBE or control (saline) challenge and examined whether BAL cells were activated in vitro to produce other inflammatory agonists. After CBE administration, cultured BAL cells released increased amounts of the reactive O2 species, superoxide (O2-.), and the cyclooxygenase products prostaglandin E2 and thromboxane B2. Although none of these in vitro parameters of BAL cell activation appeared to correlate with the degree of bronchoconstriction induced by CBE, BAL fluid levels of thromboxane B2 were also increased after CBE administration and in vivo amounts of this eicasanoid did correlate with the degree of bronchoconstriction induced by CBE (r = 0.50, P less than 0.04). Finally, although cell culture supernatants were highly chemotactic for PMN's, concentrations of leukotriene B4 were not increased, suggesting other chemotaxins were released by BAL cells in this setting. We conclude that CBE administration activates bronchoalveolar cells to release reactive O2 species and cyclooxygenase products that may be important in the bronchoconstricting response to CBE.

Pulmonary immunology.

The lower respiratory tract of normal healthy individuals is kept sterile and disease-free by formidable local and systemic immune system defenses. In patients with AIDS, these defenses are severely compromised. Undoubtedly, alterations in both local and systemic forces make the host vulnerable to infection by opportunistic organisms. Indeed, substantial evidence suggests that at least a small percentage of macrophages, which normally function alone and in concert with other immune components, can be and are infected with HIV, and do not function normally. Abnormalities with lymphocytes in the lung may contribute to macrophage defective function. Further investigations into the role of lung macrophages and other lower respiratory tract defenses are needed if we are to comprehend fully the mechanisms that lie behind the multitude of pulmonary complications associated with AIDS.

Effects of in vitro amiodarone exposure on alveolar macrophage inflammatory mediator production.

Administration of amiodarone, although often lifesaving, is associated with pulmonary side effects. Patients with amiodarone pulmonary toxicity can present with either a chronic disorder that suggests pulmonary fibrosis or a more acute process. Mechanisms of acute pulmonary injury resulting from amiodarone are unclear. Previous studies have demonstrated that the drug is preferentially concentrated in alveolar macrophages. In the present study, the authors examined whether in vitro exposure to amiodarone resulted in alteration of rat alveolar macrophage superoxide, leukotriene B4, or fibronectin release. In addition, the authors assessed whether macrophages were ultrastructurally altered by in vitro amiodarone exposure. Twenty four hour exposure to therapeutic tissue concentrations of amiodarone resulted in enhancement of phorbol myristate acetate-stimulated macrophage superoxide release. In addition, 48 hours exposure to amiodarone caused a dose-dependent inhibition of spontaneous fibronectin release by macrophages. Macrophages exposed to 48 hours of 10 micrograms/ml amiodarone were ultrastructurally abnormal, containing lamellar inclusions and demonstrating a large degree of vacuolization. The authors concluded that alveolar macrophages are very sensitive to therapeutic tissue concentrations of amiodarone. Alteration of macrophage mediator release by amiodarone may be one mechanism for lung damage induced by the drug.

Atypical presentation of acute myocardial infarction in 3 age groups.

OBJECTIVE: The purpose of this study was to compare the clinical manifestations of first-time acute myocardial infarction (AMI) in 3 age groups of men and women who presented to the emergency departments of 3 acute tertiary care hospitals. DESIGN: An exploratory, descriptive design was used, and there were 2 phases to the project. Phase 1 was a retrospective chart audit of a systematic random sample of patient charts, and phase 2 included a structured interview of a prospective random sample of emergency and intensive care unit nurses and physicians. The data were collected by using a chart audit tool and a semistructured interview, respectively. SETTING: The study took place at a western Canada university affiliated with acute tertiary care centres. SAMPLE: A systematic random sample of 153 (105 men and 48 women) patient charts were audited from the health records departments of 3 acute care hospitals. All of the patients had experienced a first-time AMI. In addition, a random sample of emergency/intensive care unit nurses (n = 60) and physicians (n = 18) was interviewed. RESULTS: The results indicate that a statistically significant number of the oldest (75 years or older) male patients present with atypical manifestations of AMI compared with the men in the younger age groups (P =.005). The same trend was not noted for female patients. The results of the study are limited with respect to the small number of women in each age category. Caution must therefore be exercised in generalizing the results to the target population of women with AMI. The atypical manifestations are described. The results of the interviews revealed that many clinicians do not look for different clinical manifestations when assessing older patients. CONCLUSIONS: It is essential that nurses and physicians accurately assess patients with AMI, especially patients in the older age groups who may be presenting atypically. It is also important that professional and nonprofessional public health education initiatives include information regarding both typical and atypical presentation of AMI, particularly in the older patient.

Patients' preferences for dentists' behaviors.

Unlike previous studies that examined specialized populations or were completed some years ago, this survey collected information from a cross-section of patients who were currently receiving various kinds of dental treatment. Although the study disclosed that patients' preferences and perceptions of dentists' performance might vary within and between demographic groups, a more important finding was that, in general, most patients in all demographic groups held common beliefs about how they would like to be treated by their dentists. However, according to the reports of these patients, the dentists did not always behave in ways that were congruent with the patients' preferences. The study showed that patients are sensitive to dentists' behaviors. It should also be noted that dentists are sensitive to patients' behaviors and that dentist-patient relationships may be a source of stress for both patients and dentists. Nevertheless, the responsibility for setting the tone of these relationships rests primarily with the dentist rather than with the patient. Therefore, it is important for dentists to be aware of the needs and preferences of their patients so that they can act in ways that will make patients comfortable and dental treatment a positive experience. The potential that appears to be inherent in good, satisfying dentist-patient relationships for minimizing patient stress and making dentistry a less stressful profession has yet to be fully realized. Dentistry is a two-way street: whatever benefits the patient should in turn benefit the dentist as well.

Nursing students' preferences in the use of computer assisted learning.

One hundred and ten student nurses in the second year of a 3-year diploma program were surveyed following their use of computer assisted learning (CAL) programs. The questionnaire was designed to elicit responses concerning the preferred number of users per terminal, the level of supervision (supervised/unsupervised) and their general affective response to this type of learning. The results showed that the majority (56.4%) of students preferred to work in a group (a group constituted no more than three students per terminal). Whereas 31.8% preferred to work through the program alone, just over 50% would rather be supervised while running the program, and 26.4% expressed a preference for no supervision. There was no relationship found between program content and running the program alone or with others. However, in 10% of the sample there was a positive relationship found between the need for supervision and program content. The reasons given for these preferences and the advantages and disadvantages of CAL, as perceived by the students, are also discussed.

Pathophysiology of the rheumatoid joint.

The precise cause of rheumatoid arthritis (RA) is, as yet, unknown. But with more sophisticated techniques in the fields of immunogenetics and molecular biology, there is increasing knowledge of the pathophysiology of the rheumatoid joint. Pathophysiologic knowledge should be part of the orthopaedic nurse's repertoire when dealing with the "whole" patient; therefore orthopaedic nurses who care for patients with rheumatoid disease should understand certain pathophysiologic concepts. This article reviews the pathophysiology of the rheumatoid joint and describes the changes that take place in the joint with specific reference to the cells of the immune system, the synovium, and articular cartilage.