Mitochondrial dysfunction has been implicated in the pathogenesis of insulin resistance and type 2 diabetes. Damaged mitochondria DNA (mtDNA) may have a role in regulating hyperglycemia during type 2 diabetes. Circulating cell-free mitochondria DNA (ccf-mtDNA) was found in serum and plasma from patients and has been linked to the prognosis factors in various human diseases. However, the role of ccf-mtDNA in chronic inflammation in type 2 diabetes is unclear. In this study, we hypothesized that the ccf-mtDNA levels are associated with chronic inflammation in patients with type 2 diabetes. The mtDNA levels were elevated in the plasma from patients with type 2 diabetes compared to healthy subjects. The elevated mtDNA levels were associated with interleukin-1 (IL-1)β levels in patients with type 2 diabetes. The mtDNA, from patients with type 2 diabetes, induced absent in melanoma 2 (AIM2) inflammasome-dependent caspase-1 activation and IL-1β and IL-18 secretion in macrophages. Our results suggest that the ccf-mtDNA might contribute to AIM2 inflammasome-mediated chronic inflammation in type 2 diabetes.

Diagnostic tests for respiratory viral infections use traditionally either nasopharyngeal washes or swabs. Sputum is representative of the lower respiratory tract but is used rarely for viral testing. The aim of this study was to compare the detection rates of respiratory viruses from nasopharyngeal swabs and sputum using a multiplex real-time reverse transcription-polymerase chain reaction (RT-PCR). Adults who were admitted or presented to the clinics of Gil Medical Center with acute respiratory symptoms were recruited from 1 November 2012 to 31 March 2013. Paired specimens of nasopharyngeal swabs and sputum were obtained from 154 subjects, and RNA was extracted and tested for 16 different respiratory viruses using the Anyplex II RV16 Detection kit (Seegene, Seoul, Korea). The positive rate was 53% (81/154) for nasopharyngeal swabs and 68% (105/154) for sputum (P < 0.001). One hundred thirty-four viruses were identified for 107 illnesses. Influenza A virus, RSV A, HRV, coronavirus OC43, and adenovirus were detected more frequently in sputum samples than in nasopharyngeal swabs (P < 0.001). Importantly, 12 of 44 (27%) influenza A infections and 11 of 27 (41%) RSV infections were positive in only sputum samples. The detection rates of respiratory viruses from sputum samples were significantly higher than those from nasopharyngeal swabs in adults using real-time multiplex RT-PCR. These findings suggest that sputum would benefit for the detection of respiratory viruses by nucleic acid amplification tests (NAATs) in patients who produce sputum. Further studies are needed to establish standardized RNA extraction methods from sputum samples.

Idiopathic pulmonary fibrosis (IPF) has been linked to chronic lung inflammation. Drosha ribonuclease III (DROSHA), a class 2 ribonuclease III enzyme, plays a key role in microRNA (miRNA) biogenesis. However, the mechanisms by which DROSHA affects the lung inflammation during idiopathic pulmonary fibrosis (IPF) remain unclear. Here, we demonstrate that DROSHA regulates the absent in melanoma 2 (AIM2) inflammasome activation during idiopathic pulmonary fibrosis (IPF). Both DROSHA and AIM2 protein expression were elevated in alveolar macrophages of patients with IPF. We also found that DROSHA and AIM2 protein expression were increased in alveolar macrophages of lung tissues in a mouse model of bleomycin-induced pulmonary fibrosis. DROSHA deficiency suppressed AIM2 inflammasome-dependent caspase-1 activation and interleukin (IL)-1β and IL-18 secretion in primary mouse alveolar macrophages and bone marrow-derived macrophages (BMDMs). Transduction of microRNA (miRNA) increased the formation of the adaptor apoptosis-associated speck-like protein containing a caspase recruitment domain (ASC) specks, which is required for AIM2 inflammasome activation in BMDMs. Our results suggest that DROSHA promotes AIM2 inflammasome activation-dependent lung inflammation during IPF.

Nocardia cerebral abscess is rare, constituting approximately 1-2% of all cerebral abscesses. Mortality for a cerebral abscess of Nocardia is three times higher than that of other bacterial cerebral abscesses, therefore, early diagnosis and therapy is important. Nocardia cerebral abscess is generally occur among immunocompromised patients, and critical infection in immunocompetent patients is extremely rare. We report on a case of a brain abscess by Nocardia farcinica in an immunocompetent patient who received treatment with surgery and antibiotics. This is the second case of a brain abscess caused by N. farcinica in an immunocompetent patient in Korea.

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