The epidemiology of HIV-1 infection of the lung in AIDS patients.

OBJECTIVE: To examine the relationship between HIV-1 infection of cells obtained by bronchoalveolar lavage (BAL) from the lung and the pathogenesis of AIDS. DESIGN: Prospective study of 121 consecutive HIV-1-seropositive patients undergoing investigation for respiratory symptoms or abnormal chest radiograph. METHODS: Polymerase chain reaction (PCR) for the detection of HIV-1-specific proviral DNA. Cocultivation of leukocytes obtained from BAL with donor cord blood leukocytes (CBL) to isolate HIV-1. RESULTS: HIV-1 was detected by PCR in the lung cells of 78 out of 121 (65%) patients. It was detected in 55% of patients who had been seropositive for less than 1 year, but in over 80% of patients who had been seropositive for more than 3 years. HIV-1 was isolated from 61 out of 106 (58%) individuals. The ability to detect or isolate HIV-1 from the lung correlated directly to CD4 cell count in peripheral blood. HIV-1 was detected significantly more frequently in the BAL cells of smokers compared with non-smokers (P = 0.01). CONCLUSIONS: HIV-1 was frequently detected and isolated from the lung of AIDS patients undergoing a respiratory episode. HIV-1 infection of the lung became more frequent with time from serodiagnosis. Patients who smoked were more likely to succumb to HIV-1 infiltration into the lung and HIV-1 infection of the lung was associated with progression to death.

Physiological response to moderate exercise workloads in a pulmonary rehabilitation program in patients with varying degrees of airflow obstruction.

STUDY OBJECTIVES: To investigate whether a 12-week pulmonary rehabilitation program that includes moderately intensive exercise training performed twice weekly can induce a training effect in patients with a wide variation of airflow limitation. PARTICIPANTS: Sixty patients with COPD (38 men) with a mean +/- SD FEV(1) % predicted of 55.1 +/- 19.8 (range, 0.51 to 2.99). All patients performed identical incremental symptom-limited cycle ergometer testing before and after a 12-week study period. MEASUREMENTS AND RESULTS: After 12 weeks, the patients demonstrated a significant (p < 0.05) increase in the peak values for work rate (WR; 77 +/- 30 vs 91 +/- 36 W) and oxygen uptake (1.14 +/- 0.45 vs 1.20 +/- 0.52 L/min). Furthermore, at a given WR during incremental symptom-limited cycle ergometer testing, there were significant (p < 0.05) reductions in minute ventilation (42.4 +/- 16.1 vs 37.0 +/- 13. 6 L/min), carbon dioxide output (1.13 +/- 0.49 vs 1.03 +/- 0.42 L/min), ventilatory equivalent for oxygen (37.6 +/- 8.1 vs 36.0 +/- 6.3), and heart rate (135 +/- 15 vs 128 +/- 16 beats/min). None of the observed physiologic changes correlated with FEV(1) % predicted. CONCLUSIONS: A pulmonary rehabilitation program performed twice weekly with moderate exercise workloads can lead to a physiologic training response irrespective of the degree of airflow limitation.

Urinary leukotriene E4 excretion in exercise-induced asthma.

Recent evidence suggests that the cysteinyl-leukotrienes (LTC4, LTD4, and LTE4) may be important in the pathogenesis of exercise-induced asthma. To evaluate the role of these mediators further, nine asthmatic subjects with exercise-induced bronchoconstriction were studied on two occasions. On visit 1, subjects performed 6 min of treadmill exercise; the mean maximal percent fall in FEV1 was 38.0 +/- 5.3%. On visit 2, maximal bronchoconstriction observed after exercise was matched with aerosolized methacholine. Urine was collected in two 90-min fractions (0-90 and 90-180 min) after challenges and analyzed by high-performance liquid chromatography-radioimmunoassay for LTE4. There were no significant differences in urinary LTE4 excretion between exercise and methacholine challenges for the periods 0-90 min (16.9 +/- 5.4 vs. 20.4 +/- 4.2 ng/mmol urinary creatinine), 90-180 min (24.9 +/- 8.2 vs. 20.1 +/- 5.5), or 0-180 min (21.5 +/- 6.5 vs. 18.8 +/- 4.1). Thus in contrast to allergen-induced bronchoconstriction, there is little evidence for enhanced cysteinyl-leukotriene generation in exercise-induced bronchoconstriction as assessed by urinary LTE4. If local release and subsequent participation of functionally active cysteinyl-leukotrienes in the pathways that ultimately lead to bronchoconstriction after exercise challenge do occur, these are of insufficient magnitude to perturb urinary LTE4 excretion.

Inhaled PAF stimulates leukotriene and thromboxane A2 production in humans.

Platelet-activating factor (PAF) is a potent bronchoconstrictor in humans and has been implicated as an inflammatory mediator in asthma. This study was performed to evaluate whether PAF-induced bronchoconstriction in vivo could be mediated through the release of the bronchoconstrictor eicosanoids, thromboxane (Tx) A2 and the cysteinyl leukotrienes. Ten asthmatic subjects were studied on three occasions after bronchial challenges with aerosolized PAF, methacholine, or isotonic saline. PAF caused bronchoconstriction in all 10 subjects (mean maximal percent fall in specific airway conductance 48.2 +/- 4.6) and was matched by methacholine challenge. Saline caused no changes in specific airway conductance. Urinary leukotriene E4 was significantly elevated after inhaled PAF (366.0 +/- 66.9 ng/mmol creatinine, P less than 0.01) compared with methacholine (41.6 +/- 13.3) and saline (33.6 +/- 4.6). The major urinary TxA2 metabolite 2,3-dinor TxB2 was elevated after inhaled PAF (41.3 +/- 7.1 ng/mmol creatinine, P less than 0.01) compared with methacholine (14.0 +/- 2.7) and saline (17.1 +/- 3.9). Urinary 2,3-dinor 6-oxo-prostaglandin F1 alpha after PAF (22.2 +/- 1.4) was raised with respect to the methacholine challenge (13.9 +/- 1.8, P less than 0.02), although no significant increase was observed compared with the saline control (18.6 +/- 3.3). Inhaled PAF leads to the secondary generation of cysteinyl leukotrienes and TxA2, and it is possible that these mediate some of the acute effects of inhaled PAF in vivo.

Urinary N tau-methylimidazole acetic acid excretion in respiratory disease.

N tau-methylimidazole acetic acid (N tau-MIAA) is the principal urinary metabolite of histamine. The basal urinary excretion rate of N tau-MIAA was determined as 0.117 +/- 0.008 (SE) mg/h, with a renal clearance for N tau-MIAA of 273 +/- 27 ml/min implying active secretion. After subpharmacological infusion of histamine (50 ng.kg-1.min-1 over 2 h) in five volunteers that increased plasma histamine from 0.28 +/- 0.04 to 0.71 +/- 0.15 ng/ml, urinary excretion of N tau-MIAA over 8 h was increased by less than 17% compared with a control saline infusion. Urinary N tau-MIAA excretion in normal controls (273 +/- 14 micrograms/mmol creatinine) was similar to that observed in patients with severe acute asthma (253 +/- 22 micrograms/mmol), antigen-induced bronchoconstriction (269 +/- 21 micrograms/mmol), seasonal allergic rhinitis (304 +/- 31 micrograms/mmol), and clinically stable bronchiectasis (270 +/- 22 micrograms/mmol). In contrast, large increases in metabolite excretion (greater than 7,000 micrograms/mmol creatinine) were observed in a patient with systemic mastocytosis where very high plasma histamine levels were recorded (greater than 500 ng/ml) and marked systemic hemodynamic effects occurred. We conclude that urinary N tau-MIAA will only be increased in pathologies where sustained hyperhistaminemia occurs and that increased local histamine production in the lung or the upper airway does not cause a measurable change in the basal urinary excretion of this metabolite.

Muscarinic receptors in rat intestinal muscle: comparison with the guinea pig.

The properties of muscarinic receptors in rat intestinal muscle have been investigated by examining the binding of 3H-propylbenzilylcholine mustard, 3H-PrBCM, a specific and virtually irreversible muscarinic antagonist. It is shown that the properties of these muscarinic receptore correspond in general closely to those observed in the guinea pig, in particular the binding curve inferred for carbachol shows the same apparent negative cooperativity, but there is a notable difference in the rate of binding 3H-PrBCM.

Identification of M. tuberculosis ribosomal RNA in mouthwash samples from patients with tuberculosis.

It is often not possible to obtain satisfactory sputum samples from patients suspected of having pulmonary tuberculosis. In this study, we asked whether it was possible to identify M. tuberculosis ribosomal RNA (rRNA) in mouthwash samples, and in a prospective clinical study, whether the presence of this rRNA correlated with clinical M. tuberculosis infection. Using a combination of reverse transcriptase and polymerase chain reaction amplification, it was possible to identify M. tuberculosis rRNA in mouthwash samples. M. tuberculosis rRNA was identified in mouthwash samples from patients with active tuberculosis more commonly than in samples from control subjects (P < 0.05). The test was positive in four of ten patients with active pulmonary tuberculosis, one of eight contacts, none of eight past cases of tuberculosis, two of eight patients with other diagnosis and one of five healthy volunteers. M. tuberculosis rRNA was identified in sputum from four of eight patients and in bronchoscopy trap samples from four of five patients with active tuberculosis. However, one of ten sputum samples and two of five bronchoscopy samples from subjects with a clinical diagnosis other than active tuberculosis were positive. These results indicate that although it is technically possible to identify M. tuberculosis on the basis of the presence of rRNA in mouthwash samples, the poor sensitivity and specificity of the technique suggest that it is unlikely to be useful clinically.

Acute effects of nebulised epoprostenol in pulmonary hypertension due to systemic sclerosis.

Pulmonary hypertension often has a lethal outcome in systemic sclerosis and the treatment is challenging. Epoprostenol is a potent pulmonary vasodilator and its efficacy has been demonstrated when delivered by the intravenous and aerosolized routes. We report the haemodynamic and functional benefits of epoprostenol administered by inhalation to a spontaneously breathing patient with partially reversible pulmonary hypertension due to systemic sclerosis. Aerosolized epoprostenol, equivalent to the maximum tolerated intravenous dose (31.2 micrograms), produced a 58% fall in pulmonary vascular resistance, increased the cardiac output by 42% and improved functional performance by one MET (3.5 ml kg-1 min-1 of oxygen uptake) without any significant side-effects. Selective distribution of epoprostenol by the inhaled route may offer a new strategy for treatment of pulmonary hypertension.

Asthma in the elderly: underperceived, underdiagnosed and undertreated; a community survey.

Bronchial asthma is now increasingly recognized in the elderly and is associated with significant morbidity and mortality. The aims of this study were two-fold: first, to assess the prevalence and, second, to evaluate diagnostic awareness, therapeutic management and patient perception of bronchial asthma among elderly patients in the community. From the age-sex register of an urban general practice in NE England, 2004 patients aged > 65 years were eligible for inclusion. Response to an initial screening questionnaire on respiratory symptomatology was 68% (n = 1362). Of these, 869 patients had respiratory symptoms: 390 voluntarily agreed to be evaluated further including assessment of airway physiology. In this group 369/390 had obstructive spirometry and, of these, 95 patients fulfilled clinical and physiological criteria of bronchial asthma. Prevalence of asthma within this age cohort was minimally and rather crudely assigned at 4.5% (95/2004). Among the 95 patients so-defined patients with asthma [age 70 +/- 8 years (mean +/- SD), FEV1 = 0.96 +/- 0.41, 33 male, 75 life-long non-smokers], subjective awareness, perception and attribution of pulmonary symptoms were poor. Further, despite tangible evidence of reversible and significant airflow limitation, only 21 were receiving inhaled glucocorticoid therapy (median daily dose 400 micrograms). Asthma in the elderly remains poorly perceived, poorly recognized and suboptimally treated. These findings are particularly apposite in the light of current epidemiological trends in asthma mortality and morbidity in elderly age cohorts.

Pharmacological modulation of platelet-derived growth factor (B) mRNA expression in alveolar macrophages and adherent monocytes.

The macrophage profibrotic cytokine, Platelet Derived Growth Factor B [PDGF(B)], is thought to play a central role in orchestrating the fibrotic response in the pathogenesis of cryptogenic fibrosing alveolitis. In this study, we have asked if drugs that increase intracellular cAMP and are commonly administered to patients with lung disease have the ability to downregulate PDGF(B) mRNA. Incubation of human alveolar macrophages from healthy smokers in the presence of dibutyryl cAMP prevented the previously reported dexamethasone-induced increase in PDGF(B) mRNA (P < 0.05). Similarly, the combination of aminophylline (2.5 mM) and salbutamol (1 microM) prevented the adherence-dependent increase in PDGF(B) mRNA in adherent human peripheral blood monocytes (P < 0.05), whilst causing an increase in the mRNA expression of the cAMP-dependent gene c-fos (P = 0.059), and an increase in the intracellular concentration of cAMP (P = 0.05). Finally, the presence of a lower concentration of aminophylline (0.25 m) in conjunction with salbutamol (1 microM) also prevented the dexamethasone-induced increase in PDGF(B) mRNA in alveolar macrophages from healthy smokers (P < 0.05). Stimulation by these drugs was not associated with a change in the abundance of the mRNA of the house-keeping gene, glyceraldehyde-3-phosphate dehydrogenase. We speculate that drugs, which increase intracellular cAMP, may provide a novel therapeutic avenue whereby PDGF(B) expression in patients with cryptogenic fibrosing alveolitis may be reduced.

Gas chromatographic-mass spectrometric assay to measure urinary N tau-methylhistamine excretion in man.

An assay has been developed for N tau-methylhistamine, a major metabolite of the autocoid histamine, based on gas chromatography-electron-capture negative-ion chemical ionisation mass spectrometry. N tau-Methylhistamine was extracted from urine by cation-exchange chromatography and converted to its di-(3,5-bistrifluoromethylbenzoyl) derivative. The latter has good chromatographic properties and gives a negative-ion mass spectrum with the molecular ion (M., m/z 605) as base peak. A commercially available trideuterated analogue of N tau-methylhistamine was used as internal standard. Basal urinary excretion of N tau-methylhistamine in five normal subjects was found to be 0.21 +/- 0.05 mumol/h (289 +/- 74 mumol/mol of creatinine). This value was not significantly altered in these subjects following the infusion of a subpharmacological dose of histamine. In eight atopic volunteers, basal urinary excretion of N tau-methylhistamine was also not significantly changed following challenge with inhaled allergen.

Up-regulation of alveolar macrophage platelet-derived growth factor-B (PDGF-B) mRNA by interferon-gamma from Mycobacterium tuberculosis antigen (PPD)-stimulated lymphocytes.

Macrophage production of PDGF-B is believed to be important in the pathogenesis of diseases where chronic lung inflammation develops into fibrosis. Since tuberculosis is characterized by chronic inflammation and tissue fibrosis, we asked if lymphokines from lymphocytes stimulated by the Mycobacterium tuberculosis antigen PPD, contained factors capable of increasing human alveolar macrophage PDGF-B mRNA. Supernatants from both phytohaemagglutinin (PHA)- and purified protein derivative (PPD)-stimulated lymphocytes, when added to macrophages, induced an increase in the mRNA of PDGF-B, but not transforming growth factor-beta (TGF-beta). When lymphocytes from contacts of patients with tuberculosis, patients with tuberculosis, and normal subjects were compared following PPD stimulation, the lymphocytes from the contacts had the greatest proliferation response, the greatest production of interferon-gamma (IFN-gamma), and their lymphokines induced the greatest increase in PDGF-B mRNA in macrophages. Recombinant human IFN-gamma reproduced this ability of lymphokines to increase macrophage PDGF-B mRNA. Finally, the increase in macrophage PDGF-B mRNA following incubation with supernatants from PPD-stimulated lymphocytes was shown to be due to IFN-gamma, when the increase in macrophage PDGF-B mRNA was prevented by addition of anti-human IFN-gamma antibody to the lymphocyte supernatant. This study indicated that antigen-stimulated lymphocytes released IFN-gamma, which in turn resulted in an increase in PDGF-B mRNA in alveolar macrophages. Such a mechanism provides a link between the DTH response and the first stages of a fibrotic reaction, and may offer an explanation for the progression of chronic inflammation to fibrosis, as occurs in the lungs of patients with untreated pulmonary tuberculosis.

Relation of HIV-I in bronchoalveolar lavage cells to abnormalities of lung function and to the presence of Pneumocystis pneumonia in HIV-I seropositive patients.

BACKGROUND: HIV is present in bronchoalveolar lavage cells of some but not all HIV seropositive patients. Abnormalities of lung function have been described in such patients in the absence of clinically overt pneumonia or other respiratory infections. It is possible that the presence of HIV in alveolar macrophages could account for these abnormalities. It is also possible that the presence of HIV in alveolar macrophages contributes to immunosuppression and an increased incidence of opportunistic infections. METHODS: This was a prospective study of 157 HIV seropositive patients requiring diagnostic bronchoscopy for investigation of new respiratory symptoms, chest radiograph abnormality, or pneumonic illness. Presence of HIV in bronchoalveolar lavage cells obtained at diagnostic bronchoscopy was determined by polymerase chain reaction to detect proviral DNA and in vitro cocultivation to detect productive virus infection. With these two techniques the presence or absence of HIV in bronchoalveolar lavage was compared with the presence of abnormalities of lung function or presence of Pneumocystis pneumonia. RESULTS: HIV was detected in bronchoalveolar lavage cells in 65% of patients by means of the polymerase chain reaction and 59% with cocultivation. With both methods of detection there was no association between the presence or absence of HIV and the presence of Pneumocystis pneumonia; nor was there a relation between the presence of HIV and abnormalities of lung function. CONCLUSION: The presence of HIV in bronchoalveolar lavage cells does not predispose to an increased incidence of Pneumocystis pneumonia; nor does it contribute to abnormalities of lung function.

Comparison of polymerase chain reaction amplification of two mycobacterial DNA sequences, IS6110 and the 65kDa antigen gene, in the diagnosis of tuberculosis.

BACKGROUND: Knowledge of the sequences of mycobacterial genes and the availability of DNA amplification techniques have raised the possibility that identification of mycobacterial DNA may offer a rapid and specific diagnostic test for tuberculosis. The correlation between the presence of Mycobacterium tuberculosis DNA and clinical tuberculosis, however, is not known. This study compared the results of polymerase chain reaction amplification of two M tuberculosis DNA sequences, IS6110 and the gene encoding the 65kDa heat shock protein (65kDa Ag), from sputum, bronchoscopy washings, and bronchoalveolar lavage fluid and related these findings to the presence of active and past tuberculosis. METHODS: Highly specific primers were used for amplification of IS6110 and 65kDa Ag DNA. Analysis was performed on one or more samples from 87 patients. RESULTS: IS6110 DNA was identified in samples from all six patients with active tuberculosis, from 15 to 18 patients with past tuberculosis, from five of nine contacts of patients with tuberculosis, and from nine of 54 patients with lung disease unrelated to tuberculosis. The 65kDa Ag DNA was identified in samples from all patients with active and past tuberculosis, from contacts of patients with tuberculosis, and from 14 of 42 patients with non-tuberculous lung diseases. CONCLUSION: These data suggest that the presence of IS6110 DNA correlates more closely with a tuberculosis related diagnosis than that of 65kDa Ag DNA and that both DNAs are found in most subjects with past tuberculosis or contacts of patients with tuberculosis. This may limit the clinical usefulness of these tests.

In vivo and in vitro effects of glucocorticosteroids on arachidonic acid metabolism and monocyte function in nonasthmatic humans.

Glucocorticosteroids are used as anti-inflammatory agents in a range of diseases, however, their mechanism of action is unknown. Recently, inhibition of arachidonic acid metabolism has been suggested as one possible mechanism of action. A series of experiments were undertaken in nonasthmatic humans to examine the effects of oral prednisolone and dexamethasone and inhaled budesonide on the excretion of the urinary leukotriene E4 (LTE4), an established marker of total body leukotriene generation in vivo. In addition, the effect of the drugs on the in vitro and ex-vivo function of monocytes was examined. In vitro dexamethasone greater than 10(-8) M inhibited the thromboxane A2 (TxA2) release from human monocytes, an effect which recovered within 24 h. In vivo, neither inhaled budesonide (1.6 mg.day-1 for 7 days), nor a standard therapeutic dose of oral prednisolone (30 mg.day-1 for 3 days), nor high doses of oral dexamethasone (8 mg.day-1 for 2 days) altered the excretion of urinary LTE4, despite the latter completely suppressing endogenous cortisol production. The ex-vivo zymosan stimulated release of TxA2 release from monocytes was not altered by the standard dose prednisolone, but was reduced by high dose dexamethasone and inhaled budesonide. This study shows that high doses of systemic steroids have little effect on arachidonic acid metabolism in normal nonasthmatic humans. Inhaled budesonide, however, does reduce arachidonic acid metabolism in circulating monocytes, presumably by affecting these cells during their passage through the lung.