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Increased exhaled nitric oxide in active pulmonary tuberculosis due to inducible NO synthase upregulation in alveolar macrophages

Nitric oxide (NO) plays an important role in resistance to Mycobacterium tuberculosis infection. Our aim was to determine whether inducible NO synthase (iNOS) expression and generation of reactive nitrogen intermediates (RNI) by alveolar macrophages (AM) are increased in patients infected with M. tuberculosis. NO levels in the exhaled air of 19 active pulmonary tuberculosis (TB) and 14 control subjects were measured using a chemiluminescence NO analyser. The expression of iNOS on AM was studied by labelling AM with anti-mac iNOS polyclonal antibody analysed with a flow cytometer. The spontaneous generation of RNI by cultured AM was also measured. Data are presented as mean+/-SEM. The level of NO in exhaled air was higher in patients with active TB (16.2+/-1.2 parts per billion (ppb)) compared to control subjects (6.5+/-0.9 ppb), p<0.0001. Exhaled NO decreased with anti-TB treatment. Compared to control subjects (29.0+/-4.5 fluorescence intensity (FI)), iNOS expression on AM was upregulated in TB patients (86.3+/-12.5 FI) p<0.001 and the capacity for spontaneous generation of nitrite was enhanced. Nitrite production was inhibited by N(G)-monomethyl-L-arginine (L-NMMA), a competitive inhibitor of iNOS. The expression of iNOS on AM was related to the concentration of exhaled NO (r=0.66, p<0.001) and the nitrite generation capacity of AM (r(s)=0.77, p<0.001). We conclude that the increase in exhaled nitric oxide observed in patients with active pulmonary tuberculosis is due to an upregulation of inhaled NO synthase expression in alveolar macrophages which have an enhanced capacity for nitric oxide production.

Increased level of exhaled nitric oxide and up-regulation of inducible nitric oxide synthase in patients with primary lung cancer.

Monocyte-macrophage series have an important role in host surveillance against cancer. The cytotoxic/cytostatic activity of macrophages is, to a great extent, attributed to the up-regulation of inducible nitric oxide synthase (iNOS) and production of nitric oxide (NO). Here, in 28 patients with primary lung cancer and 20 control subjects, we measured the concentration of exhaled NO and nitrite in epithelial lining fluid (ELF) using a chemiluminescence NO analyser, and studied NOS expression in alveolar macrophages (AM) and lung tissues by flow cytometry; immunohistochemical analysis was also undertaken. The mean fluorescence intensity (FI) of iNOS expression in AM was significantly increased in patients with lung cancer (tumour side 263.5 +/- 15.2 FI, normal side 232.4 +/- 18.6 FI; n = 28) compared with that in control subjects (27.3 +/- 3.2 FI; n = 20, P< 0.001). The level of exhaled NO from cancer patients (16.9 +/- 0.9 p.p.b.; n = 28) was significantly higher than that in the control group (6.0 +/- 0.5 p.p.b.; n = 20, P < 0.001). The level of nitrite was also significantly higher in ELF from cancer patients (tumour side 271.1 +/- 28.9 nM and normal side 257.4 +/- 19.6 nM vs control subjects 32.9 +/- 4.1 nM; P< 0.001). The intensity of iNOS expression in AM was correlated with the level of exhaled NO (rs = 0.73, n = 76, P< 0.001) and the nitrite released in ELF (rs = 0.56, n = 76, P< 0.001). The nitrite generation of cultured AM from patients with lung cancer was significantly enhanced compared with that of control subjects after culture for 24 h (tumour side 5.75 +/- 0.69 and normal side 5.68 +/- 0.58 microM per 106 cells vs control group 38.3 +/- 3.6 nM per 106 cells; P< 0.001). The distribution of iNOS was identified in AM, tumour-associated macrophages, endothelium, chondrocytes, airway epithelium of both lungs and malignant cells (adenocarcinoma and alveolar cell carcinoma) of cancer patients. cNOS was labelled in alveolar macrophages, endothelial cells and nerve elements from lung tissue. Our results indicate that, in patients with primary lung cancer, the production of NO from alveolar macrophages was increased as a result of the up-regulation of iNOS activity. The increased NO production was not specific to the tumour side and might be attributed to the tumour-associated non-specific immunological and inflammatory processes of the host.

Metallic stent and flexible bronchoscopy without fluoroscopy for acute respiratory failure.

Stent implantation has been reported to facilitate liberation from mechanical ventilation in patients with respiratory failure due to central airway disease. The present retrospective cohort study sought to evaluate the risk and benefit of stent implantation via bronchoscopy without fluoroscopic guidance in mechanically ventilated patients. From July 2001 to September 2006, 26 patients with acute respiratory failure were recruited. A bronchoscope was inserted through a mouth guard into the space between the tracheal wall and the endotracheal tube. A guide wire was inserted via the flexible bronchoscope to the lesion site. The bronchoscope was reintroduced through the endotracheal tube. Under bronchoscopic visualisation, the delivery catheter was advanced over the guide wire to deploy the stent. These procedures were successfully performed in 26 patients, with 22 stents placed in the trachea and seven in the main bronchus. Of the 26 patients, 14 (53.8%) became ventilator independent during their stay in the intensive care unit. Severe pneumonia was the most common cause, in seven (58.3%) out of 12 patients, for continued ventilator dependence after stenting. Granulation tissue formation was found in seven patients during the follow-up period. It is concluded that metallic stents can be safely implanted without fluoroscopic guidance in patients with respiratory failure, to facilitate ventilator independence.

Differential effects of nasal continuous positive airway pressure on reversible or fixed upper and lower airway obstruction

Our study was to assess whether there were differential effects of nasal continuous positive airway pressure (nCPAP) on different kinds of obstruction in either upper or lower airways in patients with chronic obstructive pulmonary disease (COPD). nCPAP (6 cmH2O for ten minutes) was applied to 7 patients with reversible extrathoracic upper airway obstruction (RUAO) and 3 patients with fixed extrathoracic upper airway obstruction (FUAO). Eighteen stable asthmatics, receiving methacholine challenge to induce a more than 20% reduction in FEV1, were randomly investigated for the effect of nCPAP or sham pressure on reversible lower airway obstruction. Nine stable COPD patients were enrolled to study the effect on irreversible lower airway obstruction. Maximal expiratory and inspiratory flow volume curves and dyspnoea scores were obtained before and after immediate withdrawal of nCPAP. In the RUAO group, nCPAP significantly improved stridor and dyspnoea scores, decreased the ratio of FEF50/FIF50 from 2.05 +/- 0.25 to 1.42 +/- 0.16, and increased peak inspiratory flow (PIF) as well as forced inspiratory vital capacity by 26 +/- 8% and 9 +/- 4%, respectively. In expiratory phase, there was no significant change in pulmonary functions. In asthmatics, nCPAP significantly reversed methacholine-induced bronchoconstriction increasing forced vital capacity by 10 +/- 3%, FEV1 by 15 +/- 4% and PIF by 32 +/- 11%. nCPAP significantly increased the response to bronchodilators. The improvement in airflow rate persisted for at least 5 min after nCPAP withdrawal and was highly correlated with the response to bronchodilators. There was no significant effect of nCPAP on airflow rate in COPD patients. Subjective dyspnoea score changes paralleled the pulmonary function improvement. We conclude that there are differential effects of nCPAP on airflow rates in patients with different nature of airway obstruction. Patients with airway obstruction caused by structural changes may not benefit from the use of nCPAP in improving airflow rates.

Multimodality Treatment and Long-Term Follow–Up of the Primary Pulmonary Lymphoepithelioma-Like Carcinoma

INTRODUCTION Primary pulmonary lymphoepithelioma-like carcinoma (LELC) is a very rare subtype of non-small-cell lung cancer. Most cases are reported in Southeast Asia and are associated with Epstein-Barr virus infections. Because of its rare incidence, the optimal treatment and the results of long-term follow-up are not well understood. This study is an attempt to discover the multimodality treatment results of the primary pulmonary LELC. METHODS This retrospective study enrolled 21 patients with primary pulmonary LELC treated at 2 hospitals with a multimodality approach, including surgery, chemotherapy, radiotherapy, and targeted therapy. RESULTS The median follow-up time is 5.9 years and the median survival is 6.4 years. The median overall survival for patients with stage III and with stage IV disease is 3.4 years. In early-stage primary pulmonary LELC, surgery and adjuvant chemotherapy provided good treatment outcome. Advanced primary pulmonary LELC is relatively more chemosensitive and radiosensitive. CONCLUSION Patients with primary pulmonary LELC showed better prognosis than those with other types of non-small-cell lung cancer and achieved longer survival under multimodality treatment. This disease character is similar to that of nasopharyngeal carcinoma. Accurate pathologic diagnosis is recommended before the treatment. For advanced diseases, platinum-based doublet chemotherapy can be considered the first-line treatment. Radiation dose should consider tumor location, and 5000 to 7000 cGy is frequently applied for pulmonary LELC.

Nucleic acid amplification test and bronchoscopy improve the diagnostic accuracy of smear-negative tuberculosis

OBJECTIVE To determine whether the nucleic acid amplification (NAA) test on specimens collected by bronchoscopy improves the diagnostic accuracy of pulmonary tuberculosis (PTB) in sputum-negative patients. DESIGN Bronchoscopy was performed among smear-negative PTB suspects to collect respiratory specimens to assess the efficacy and accuracy of the Amplified Mycobacterium Tuberculosis Direct (AMTD) test in the diagnosis of PTB. RESULTS In 105 PTB suspects, 80 were finally excluded, of whom two were false-AMTD-positive. PTB (n = 25) was diagnosed in 10 patients culture-positive for Mycobacterium Tuberculosis (7/105 bronchial wash/bronchoalveolar lavage [BW/BAL] specimens, 6/315 expectorated sputum specimens [2 positive in 2 patients; 1 positive in 2 patients], and one with both), and in 15 patients with improvement after anti-tuberculosis treatment. Among the 25 PTB patients, 20 were AMTD-positive, of whom four were culture-positive. Three AMTD-negative patients were culture-positive. The sensitivity and specificity of AMTD were respectively 80.0% and 97.5%. The diagnostic yield was higher in respiratory specimens obtained at bronchoscopy and measured by AMTD than in conventional sputum or BW/BAL culture. CONCLUSION NAA testing on specimens collected using bronchoscopy provides a highly efficient and reliable approach in the diagnosis of PTB in smear-negative PTB suspects.

Apoptosis-dependent and -independent mechanisms mediate the phagocytic recognition/clearance of the HL60-A1 transfectants with prolonged survival

Abstract.Objective:The phagocytic recognition and clearance of the recruited inflammatory cells with prolonged survival play a pivotal role in relieving tissue inflammation and maintaining tissue homeostasis. Transgenic mice expressing Bcl-2 in mature neutrophils demonstrated that Bcl-2 attenuated neutrophil apoptosis, while the homeostasis of the neutrophil population was essentially unaffected. This result suggests that clearance of neutrophils with prolonged survival operates independently from apoptosis. Owing to the constitutive and inducible expression of Bcl-2 homologue, A1 in human neutrophils and the intolerance of preparation for the isolated human neutrophils with prolonged survival, the human promyelocytic HL60-A1 transfectants were established to study the mechanism of phagocytic recognition/clearance of the cells with prolonged survival.Materials and Methods:The non-apoptotic cells with prolonged survival were enriched by serum withdrawal for five days and negatively isolated by annexin V-binding beads. Then, the cells were labeled with a fluorogenic marker. Monocyte-derived macrophages (MDM) were co-cultured to perform the phagocytosis assay, and flow cytometry was employed to determine the phagocytic index.Results:In the serum-free condition, the phagocytic index of HL60-A1 transfectants was little different from that of the HL60-EGFP control, despite showing a significantly lower degree of apoptosis. While the phagocytic index of HL60-EGFP control was significantly correlated with the degree of apoptosis, the index of the HL60-A1 transfectants was less relevant to it. The phagocytic index for the annexin V-positive cells did not distinguish the two cell types. However, the phagocytic index for the annexin V-negative cells from the HL60-A1 transfectants was increased with age in days. Preincubation of MDM with the scavenger receptor inhibitor, Oxi-LDL, and the inhibitory antibodies against αvβ3, CD14 and CD36 surface molecules could attenuate the phagocytic recognition of the annexin V-positive HL60 cells but not the annexin V-negative A1 transfectants with prolonged survival.Conclusions:This study thus suggests that a mechanism unrelated to apoptosis exists, which mediates the phagocytic clearance of the non-apoptotic cells with prolonged survival and may be associated with A1 function in the myeloid cells.