Use of an adipocyte model to study the transcriptional adaptation of Mycobacterium tuberculosis to store and degrade host fat

During its persistence in the infected host, Mycobacterium tuberculosis [Mtb] accumulates host-derived fatty acids in intracytoplasmic lipid inclusions as triacylglycerols which serve primarily as carbon and energy reserves. The Mtb genome codes for more than 15 triacylglycerol synthases, 24 lipase/esterases, and seven cutinase-like proteins. Hence, we looked at the expression of the corresponding genes in intracellular bacilli persisting amidst the host triacylglycerols. We used the Mtb infected murine adipocyte model to ensure persistence and transcripts were quantified using real-time reverse transcriptase polymerase chain reaction. Dormancy and glyoxylate metabolism was confirmed by the upregulated expression of dosR and icl, respectively, by intra-adipocyte bacilli compared with in vitro growing bacilli. The study revealed that tgs1, tgs2, Rv3371, and mycolyltransferase Ag85A are the predominant triacylglycerol synthases, while lipF, lipH, lipJ, lipK, lipN, lipV, lipX, lipY, culp5, culp7, and culp6 are the predominant lipases/esterases used by Mtb for the storage and degradation of host-derived fat. Moreover, it was observed that many of these enzymes are used by Mtb during active replication rather than during nonreplicating persistence, indicating their probable function in cell wall synthesis

MALT lymphomas - Treated with chemotherapy or radiotherapy: clinical features, prognostic factors and survival

MALT lymphomas are a group of extranodal indolent lymphomas that usually present as stage IE. To clarify clinical features, treatment alternatives and outcomes, we evaluated 38 patients treated with chemotherapy or radiotherapy between 2000 and 2011. MALT lymphoma patients identified according to WHO classification and treated at KCCC between 2000 and 2011 were included in this study. Demographic and clinical data are presented as means or medians. Overall survival was estimated using the Kaplan-Meier method. Survival rates were compared using the log-rank test. A p value < 0.05 was considered significant. The median age of the patients was 49 years and the male to female ratio was 2:1. Gastric MALT accounted for 63% of all patients and the most common presenting symptom was abdomen pain and dyspepsia. The common extra gastric sites were salivary glands, lung and orbit. 90% of the patients presented with early stage disease. Two patients had history of pre-existing autoimmune disease. Even among patients who had failed prior antibiotic therapy for Helicobacter pylori, treatment with chemotherapy achieved good results with 5 year survival of 80%. MALT lymphomas are indolent neoplasm's with excellent long term outcome. There is no significant difference in survival between gastric and extra-gastric MALT lymphoma