Homologous recombination is a highly conserved determinant of the synergistic cytotoxicity between cisplatin and DNA topoisomerase I poisons.

Phase I and II clinical trails are currently investigating the antitumor activity of cisplatin and camptothecins (CPTs; DNA topoisomerase I poisons), based on the dramatic synergistic cytotoxicity of these agents in some preclinical models. However, the mechanistic basis for this synergism is poorly understood. By exploiting the evolutionary conservation of DNA repair pathways from genetically tractable organisms such as budding and fission yeasts to mammalian cells, we demonstrate that the synergism of CPT and cisplatin requires homologous recombination.

Flow patterns of mitral regurgitation due to different etiologies: analysis by color-coded Doppler echocardiography.

We have used cross-sectional real time color-coded Doppler echocardiography to characterize the patterns of the regurgitant jet seen in mitral valvar disease of different etiologies. We studied 118 patients with mitral regurgitation due to rheumatic valve disease (n = 26), hypertrophic obstructive cardiomyopathy (n = 22), dilated cardiomyopathy (n = 35) and prolapse of the leaflets of the mitral valve (n = 35). We analyzed the origin, spatial distribution, extent and duration of the regurgitant jet.

Semiquantitative grading of mitral regurgitation by color-coded Doppler echocardiography.

We evaluated patients with mitral regurgitation by color-coded Doppler echocardiography using a semiquantitative score system, which is useful in the clinical setting, by providing rapid discrimination between mild, moderate and severe regurgitation. The study was performed in 42 patients (19 female, 23 male) mean age 58 years, range 23-75 years with mitral regurgitation of different etiology. Color-coded Doppler measurements were compared to angiographic findings using a three point score system.

Elevated levels of glyoxylate shunt enzymes in Escherichia coli strains constitutive for fatty acid degradation.

Mutants of Escherichia coli K-12 constitutive for the synthesis of the enzymes of fatty acid degradation (fadR) have elevated levels of the glyoxylate shunt enzymes, isocitrate lyase and malate synthase. A temperature-sensitive fadR strain has high levels of glyoxylate shunt enzymes when grown at elevated temperatures but has low, inducible levels of glyoxylate shunt enzymes when grown at low temperatures. The increased activity of glyoxylate shunt enzymes did not appear to be due to the degradation of intracellular fatty acids in fadR strains or differences in allosteric effectors in fadR versus fadR+ strains.