Regioselectivity of Hydroxyl Radical Reactions with Arenes in Nonaqueous Solutions.

The regioselectivity of hydroxyl radical addition to arenes was studied using a novel analytical method capable of trapping radicals formed after the first elementary step of reaction, without alteration of the product distributions by secondary oxidation processes. Product analyses of these reactions indicate a preference for o- over p-substitution for electron donating groups, with both favored over m-addition. The observed distributions are qualitatively similar to those observed for the addition of other carbon-centered radicals, although the magnitude of the regioselectivity observed is greater for hydroxyl. The data, reproduced by high accuracy CBS-QB3 computational methods, indicate that both polar and radical stabilization effects play a role in the observed regioselectivities. The application and potential limitations of the analytical method used are discussed.

DNA damage regulates direct association of TOR kinase with the RNA polymerase II-transcribed HMO1 gene.

The mechanistic target of rapamycin complex 1 (mTORC1) senses nutrient sufficiency and cellular stress. When mTORC1 is inhibited, protein synthesis is reduced in an intricate process that includes a concerted down-regulation of genes encoding rRNA and ribosomal proteins. The Saccharomyces cerevisiae high-mobility group protein Hmo1p has been implicated in coordinating this response to mTORC1 inhibition. We show here that Tor1p binds directly to the HMO1 gene (but not to genes that are not linked to ribosome biogenesis) and that the presence of Tor1p is associated with activation of gene activity. Persistent induction of DNA double-strand breaks or mTORC1 inhibition by rapamycin results in reduced levels of HMO1 mRNA, but only in the presence of Tor1p. This down-regulation is accompanied by eviction of Ifh1p and recruitment of Crf1p, followed by concerted dissociation of Hmo1p and Tor1p. These findings uncover a novel role for TOR kinase in control of gene activity by direct association with an RNA polymerase II-transcribed gene.

Sonographic visualization of ovarian veins during the puerperium: an assessment of efficacy.

OBJECTIVE: The purpose of this study was to determine the ability to visualize ovarian veins by sonography in postpartum patients as well as to assess the frequency of ovarian vein thrombosis in these patients. STUDY DESIGN: Seventy subjects were recruited from either the postpartum ward or labor and delivery unit after vaginal delivery between November 1, 2000, and March 1, 2001. Patients were excluded if they had a previous or current history of venous thrombosis or recently underwent cesarean delivery. Demographic data were recorded. Transabdominal ultrasonography was performed with gray scale or color Doppler imaging for visualization of the right and left ovarian veins. Either power Doppler or pulsed Doppler imaging with spectral analysis was used for verification of the ovarian veins. Logistic regression was used for univariate analysis. RESULTS: Of the 70 parturients studied, both ovarian veins were visualized in 55 women (78.6%). Of the remaining subjects, either the right (n = 6) or the left (n = 6) ovarian vein could not be visualized. In 3 subjects, neither ovarian vein could be visualized (4.3%). An isolated, asymptomatic right ovarian vein thrombus was identified in one subject (1/55, 1.8%) after bilateral tubal ligation was performed. Maternal age, parity, body mass index, gestational age, spontaneous versus operative vaginal delivery, neonatal sex, or sonographer (radiologist versus perinatologist) did not correlate with ability to visualize the ovarian veins; however, increasing birth weight tended positively toward significance (P =.064). CONCLUSION: Most ovarian veins can be visualized sonographically during the early puerperium. Additional imaging studies should be considered when a diagnosis is unclear. The presence of an asymptomatic ovarian vein thrombus is unusual and is of uncertain importance.