The number of immunocompromised patients has increased over the past decades due to HIV infection, solid and stem cell transplantation, intensified chemotherapy and treatment of autoimmune disease. Pneumonia is a major cause of both morbidity and mortality in immunocompromised patients. Clinical management of pneumonia is difficult, since differential diagnosis in this setting is broad and includes both infectious and noninfectious processes. Because the development of pneumonia in immunocompromised patients is frequently life threatening, early therapeutic and diagnostic intervention is essential to obtain better outcomes.

The prevention of and the controlling of symptoms, reductions in the frequency of exacerbations, and disease severity are central to the pharmacologic therapy of chronic obstructive pulmonary disease (COPD). COPD patients are inclined to be older, have more comorbidities, and use polypharmacy as a result. Long-acting inhaled muscarinic antagonists (LAMAs) is a preferred treatment modality. However, the cardiovascular (CV) safety of anti-cholinergics, including LAMA, has been an issue. In contrast, the results of the UPLIFT trial and a pooled analysis of data from 30 trials of tiotropium illustrates the association of tiotropium with reductions in the risk of all cause mortality, CV mortality and CV events. And, the UPLIFT trial provides clues regarding the additive advantages of tiotropium in COPD patients who already are using long-acting inhaled ${\beta}_2$ agonists and inhaled corticosteroids. Following the contribution of tiotropium as a first LAMA, new LAMAs such as aclidinium and glycopyrrolate (NVA-237) seem to be emerging.

Background: Hyaluronan (HA) is an unbranched glycosaminoglycan. It has been proposed that HA acts as a vehicle for cytokines due to the strong negative charge on its surface. We hypothesized that HA would function like a cytokine scavenger and reduce the inflammatory signaling cascade and this would lead to improved survival in rats suffering with endotoxemia. Methods: Endotoxin (Salmonella, 10 mg/kg) or an equal amount of 0.9% NaCl (NS) was injected into the jugular vein of rats. HA (1,600 kDa, 0.35%) or NS was given at 0.1 mL/kg/h for 3 hours. HA or NS infusion was started at 4 hour after endotoxin injection. The rats were divided into the control and HA groups (n=16 for each group). The mean arterial pressure (MAP) was monitored during HA or normal saline infusion. Survival was assessed every 12 hours for 3 days throughout the experiment. Results: The survival rate (%) of the rats treated with HA was higher (60%) than that of the controls (20%) when HA was infused 4 hours after lipopolysaccharide (LPS) injection. The bronchoalveolar lavage (BAL) fluid of the animals surviving HA or NS infusion 4 hours after LPS showed that the total cell counts and number of neutrophils were significantly (p < 0.01) reduced in the HA treated groups compared with that of the controls (total cell count, $9.2{\times}10^4$/mL vs. $61{\times}10^4$/mL; neutrophils, $21{\times}10^4$/mL vs. $0.2{\times}10^4$/mL, respectively). There was no significant MAP difference between the HA or control groups either with or without endotoxin. Conclusion: Infusion of hyaluronan (1,600 kDa) reduced the BAL total cell count and the number of neutrophils and it improved the survival rate of the endotoxemic rats.

Background: To evaluate chest CT findings of pandemic influenza A/H1N1 pneumonia without co-infection. Methods: Among 56 patients diagnosed with pandemic influenza A/H1N1 pneumonia, chest CT was obtained in 22 between October 2009 and Februrary 2010. Since two patients were co-infected with bacteria, the other twenty were evaluated. Predominant parenchymal patterns were categorized into consolidation, ground glass opacity (GGO), and mixed patterns. Distribution of parenchymal abnormalities was assessed. Results: Median age was 46.5 years. The CURB-65 score, which is the scoring system for severity of community acquired pneumonia, had a median of 1. Median duration of symptoms was 3 days. All had abnormal chest x-ray findings. The median number of days after the hospital visit that Chest CT was performed was 1. The reasons for chest CT performance were radiographic findings unusual for pneumonia (n=13) and unexplained dyspnea (n=7). GGO was the most predominant pattern on CT (n=13, 65.0%). Parenchymal abnormalities were observed in both lungs in 13 cases and were more extensive in the lower lung zone than the upper. Central and peripheral distributions were identified in ten and nine cases, respectively. One showed diffuse distribution. Peribronchial wall thickening was found in 16 cases. Centrilobular branching nodules (n=7), interlobular septal thickening (n=4), atelectasis (n=1), pleural effusion (n=5), enlarged hilar and mediastinal lymph nodes (n=6 and n=7) were also noted. Conclusion: Patchy and bilateral GGO along bronchi with predominant involvement of lower lungs are the most common chest CT findings of pandemic influenza A/H1N1 pneumonia.

Background: In an effort to find alternative therapeutic agents to prevent excessive fibrosis as a sequela to complicated parapneumonic effusion or empyema, we examined the effect of tissue plasminogen activator (tPA) as a fibrinolytic agent combined with talc or transforming growth factor (TGF)-${\beta}1$ in a human pleural mesothelial cell line, MeT-5A. Methods: MeT-5A cells were stimulated with various doses of talc, doxycycline or TGF-${\beta}1$ for 24 h and then were treated with tPA for an additional 24 h. Cell viability was measured by MTT assay. The production of interleukin (IL)-8 and vascular endothelial growth factor (VEGF) in the culture supernatants was measured by ELISA. Real-time PCR was carried out for measurement of type I collagen mRNA. Results: MeT-5A cells treated with talc showed a dose-dependent increase in production of IL-8. Talc also increased production of type I collagen mRNA at low doses, but talc did not influence the induction of VEGF. Addition of tPA to talc-stimulated cells showed further increases in the production of IL-8, but tPA did not influence the production of VEGF or type I collagen mRNA. TGF-${\beta}1$ increased the production of both VEGF and collagen type I mRNA, both of which were effectively inhibited by additional tPA treatment in MeT-5A cells. Conclusion: TGF-${\beta}1$ is a potent inducer of collagen synthesis without induction of IL-8 in MeT-5A cells. Addition of tPA after TGF-${\beta}1$ stimulation inhibited further fibrosis by direct inhibition of collagen mRNA synthesis as well as by inhibition of VEGF production.

Background: Inhaled corticosteroids (ICSs) are the most essential medication for asthma control. Many reports suggest that the usage of ICSs improves not only the control of asthma symptoms but also prevents exacerbation. We investigated whether increases in ICS prescriptions are associated with decreases in asthma exacerbation in the clinical practice setting. Methods: We retrospectively analyzed the database of adult asthma patients who had visited a tertiary referral hospital, the Asan Medical Center between January 2000 and December 2009. The number of emergency department (ED) visits, admissions, intensive care unit (ICU) care, deaths, and ICS prescriptions were analyzed to evaluate the time trend of asthma exacerbation as a function of the ICS prescription rate during the ten years. Results: The numbers of ED visits, admissions, and episodes of ICU care decreased during the ten years (p<0.001, p=0.033, p=0.001, respectively) while the number of ICS prescriptions increased (p<0.001). We found a correlation between the number of ICS prescriptions and the number of ED visits, admissions, or ICU care. For these outcomes, the correlation coefficients were r=-0.952, p<0.001; r=-0.673, p=0.033; r=-0.948, p<0.001, respectively. Conclusion: The number of ICS prescriptions increased during the past ten years while the number of asthma exacerbations decreased. Our results also showed a negative correlation between the ICS prescription rate and asthma exacerbation in the clinical practice setting. In other words, an increase in ICS prescription may be a major cause of a decrease in asthma exacerbations.

Epithelioid sarcomas are rare soft tissue sarcomas with a high tumor grade and high local recurrence and metastasis rates. Although the lung is the most common site of metastasis, endobronchial metastasis hasn't been reported yet. We now report a case of epithelioid sarcoma with endobronchial metastasis. A 28-year-old man had recurrent pneumothorax and underwent wedge resection. He presented at our hospital with hemoptysis, dyspnea, and chest pain. Chest computed tomography revealed left pneumothorax, multiple lung nodules and endobronchial lesions at the right lower basal lobe. Bronchoscopy showed a hemorrhagic mass obstructing the bronchus of the right lower basal lobe. Magnetic resonance imaging revealed multiple nodular lesions in the left thigh muscles. The bronchoscopic biopsy of the endobronchial lesion and the muscle biopsy of the thigh showed the same feature epithelioid sarcoma. This is the first case report of an epithelioid sarcoma with endobronchial metastasis that was diagnosed by bronchoscopic biopsy.

Pulmonary lymphangiomatosis is a rare disorder involving the entire intrathoracic lymphatic system from the mediastinum to the pleura. Pulmonary lymphangiomatosis mostly occurs in children and young adults without gender predilection. Although it is pathologically benign, it shows a progressive and fatal course with variable initial presentation. We now report a case of pulmonary lymphangiomatosis in a 35-year-old man. He presented with hemoptysis 6 months previously. Chest x-ray and a chest computed tomography scan showed diffuse interstitial thickening with left pleural effusion. Chylothorax was confirmed by thoracentesis. Lymphangiography showed dilated and tortuous lymphatic channels. Surgical lung biopsy revealed proliferation of complex anastomosing lymphatic channels. He was diagnosed with pulmonary lymophangiomatosis. Closed thoracostomy and chemical pleurodesis were done and the dyspnea was reduced.

Sarcoidosis is a multisystemic disorder characterized by the presence of non-caseating granulomas in the involved organ. Tuberculosis is an infectious disease caused by $Mycobacterium$ $tuberculosis$ and is characterized by granuloma with caseous necrosis. The clinical and histological similarity between sarcoidosis and tuberculosis has stimulated research searching for an association between mycobacterium and sarcoidosis. We report a case of a 38-year-old male with sarcoidosis that developed soon after treatment of tuberculous lymphadenitis. He was diagnosed as tuberculous lymphadenitis by microbiological confirmation. He showed clinical improvement after treatment for tuberculosis. One year later, his chest radiography showed bilateral hilar enlargement with diffuse bilateral nodules. A noncaseating granuloma was confirmed by endobronchial ultrasound guided transbronchial needle aspiration and he was diagnosed with sarcoidosis. To our knowledge, this is the first report describing sarcoidosis after treatment of tuberculosis in South Korea.