Phenobarbital (PB) induces various gene encoding drug/ steroid-metabolizing enzymes such as cytochromes P450 (P450s) and transferases. Although the nuclear orphan constitutive active receptor (CAR) has been identified as a key transcription factor that regulates the induction of CYP2B, the full scope of CAR-regulated genes still remains a major question. To this end, reverse transcriptase-polymerase chain reaction and cDNA microarray techniques were employed to examine gene expression in wild-type and CARnull mice. The results show that a total of 138 genes were detected to be either induced or repressed in response to PB treatment, of which about half were under CAR regulation.

The peptide synthetase gene operon, which consists of mcyA, mcyB, and mcyC, for the activation and incorporation of the five amino acid constituents of microcystin has been identified [T. Nishizawa et al. (1999) J. Biochem. 126, 520-529]. By sequencing an additional 34 kb of DNA from microcystin-producing Microcystis aeruginosa K-139, we identified the residual microcystin synthetase gene operon, which consists of mcyD, mcyE, mcyF, and mcyG, in the opposite orientation to the mcyABC operon. McyD consisted of two polyketide synthase modules, and McyE contained a polyketide synthase module at the N-terminus and a peptide synthetase module at the C-terminus. McyF was found to exhibit similarity to amino acid racemase. McyG consisted of a peptide synthetase module at the N-terminus and a polyketide synthase at the C-terminus. The microcystin synthetase gene cluster was conserved in another microcystin-producing strain, Microcystis sp. S-70, which produces Microcystin-LR, -RR, and -YR. Insertional mutagenesis of mcyA, mcyD, or mcyE in Microcystis sp. S-70 abolished microcystin production. In conclusion, the mcyDEFG operon is presumed to be responsible for 3-amino-9-methoxy-2,6, 8-trimethyl-10-phenyldeca-4,6-dienoic acid (Adda) biosynthesis, and the incorporation of Adda and glutamic acid into the microcystin molecule.

Background-Remote magnetic navigation-guided ablation with 3-dimensional (3D)-image integration could provide maximum benefit in patients with complex anatomy. We reviewed supraventricular tachycardia (SVT) ablation in adult patients with congenital heart disease to assess the contribution of these technologies. Methods and Results-One hundred fifty-four SVT ablation procedures (228 SVTs) using a 3D-electroanatomic mapping system in 116 adult patients with congenital heart disease (mean age, 41; 76 male) were classified into 3 groups: Group A, manual mapping/ablation (n=60 procedures); Group B, remote magnetic navigation-guided mapping/ablation with normal femoral vein access (49)