In Iran, patients showing rifampicin (RIF) resistance detected by the Xpert® MTB/RIF assay are considered as candidates for multidrug-resistant tuberculosis (MDR-TB) treatment. Despite the fact that RIF resistance has been used as a proxy for MDR-TB, little is known about the proportion of isoniazid (INH) resistance patterns in RIF-resistant TB. We systematically searched MEDLINE, Embase, and other databases up to March 2017 for studies addressing the proportion of INH resistance patterns in RIF-resistant TB in Iran. The data were pooled using a random effects model. Heterogeneity was assessed using Cochran's Q and I statistics. A total of 11 articles met the eligibility criteria. Data analysis demonstrated that 33.3% of RIF-resistant isolates from new TB cases and 14.8% of RIF-resistant isolates from previously treated cases did not display resistance to INH. The relatively high proportion of INH susceptibility among isolates with RIF resistance indicated that RIF resistance may no longer predict MDR-TB in Iran. Therefore, the detection of RIF resistance by the Xpert MTB/RIF assay will require complementary detection of INH resistance by other drug susceptibility testing (DST) methods in order to establish the diagnosis of MDR-TB.
Cigarette smoke has been documented to be related to the development of cancer. However, the exact mechanism for the carcinogenic action of cigarette smoke is still unknown. Nicotine is recognized to be the major compound in cigarette smoke and has been suggested to play a role in oral cancer via a cyclooxygenase (COX)/ prostaglandin-dependent pathway. This study was designed to evaluate the action of nicotine in the oral cancer cell and to further examine whether COX-2 is responsible for expression of tumor-associated angiogenic vascular endothelial growth factor (VEGF) in vitro. Viability of human oral squamous cancer cells (BHY) was measured using MTT assay. Protein expression was determined by Western blot and immunoassay kits. We found that exposure of BHY cells to nicotine (200 µg/mL for 6 hours) resulted in 2.9-fold induction of COX-2 expression as well as a 4-fold increase in VEGF levels compared with a control group. Pretreatment with celecoxib inhibited nicotine-induced change in the expression of VEGF and COX-2. The results suggest that stimulation of COX-2 and VEGF expression can contribute as important factors in the tumorigenic action of nicotine in oral cancer progression. This effect can be blocked by celecoxib, suggesting an interaction of nicotine and COX-2 pathways.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.