Biological and molecular characteristics of Mycobacterium tuberculosis clinical isolates with low-level resistance to isoniazid in Japan.

We reevaluated the BACTEC MGIT 960 antimicrobial susceptibility testing system (MGIT 960 AST) by using 1,112 isolates of Mycobacterium tuberculosis. When the results of MGIT 960 AST were compared with that of the proportion method using Ogawa medium (Ogawa PM), discrepant results were obtained for 30 strains with isoniazid, all resistant by MGIT 960 AST but susceptible by Ogawa PM. For 93% of the strains that produced discrepant results, the MIC was 0.

Prooxidant activity of curcumin: copper-dependent formation of 8-hydroxy-2'-deoxyguanosine in DNA and induction of apoptotic cell death.

Curcumin, a well-known antioxidant in a principal ingredient of turmeric, acted as a prooxidant causing a copper-dependent DNA damage and the induction of apoptosis. Treatment of DNA from plasmid pBR322 and calf thymus with curcumin plus copper ion caused strand scission and the formation of 8-hydroxy-2(')-deoxyguanosine in DNA. Addition of catalase protected DNA from the curcumin-dependent injuries, indicating that hydroxyl radical may participate in the DNA damage.