In a controlled, prospective, randomized investigation, started in 1974, 118 patients with supratentorial astrocytoma Grade III--IV were divided into three groups. Groups 1 and 2 received 45 Gy postoperatively to the whole supratentorial brain. Bleomycin in 15-mg doses and a total dose of 180 mg or placebo was given intravenously three times a week, one hour prior to radiotherapy, during weeks 1, 2, 4 and 5. Group 3 received conventional care but no radiotherapy or chemotherapy. Median survival rates of patients were 10.8 months in Groups 1 and 2, and 5.2 months in Groups 3, a statistically significant difference. With regard to performance, the patients in Group 3 deteriorated faster than patients in Groups 1 and 2. Bleomycin had no positive or negative influence on survival.
Listeria monocytogenes is a bacterial pathogen that controls much of its virulence through the transcriptional regulator PrfA. In this study, we describe structure-guided design and synthesis of a set of PrfA inhibitors based on ring-fused 2-pyridone heterocycles. Our most effective compound decreased virulence factor expression, reduced bacterial uptake into eukaryotic cells, and improved survival of chicken embryos infected with L. monocytogenes compared to previously identified compounds. Crystal structures identified an intraprotein "tunnel" as the main inhibitor binding site (A), where the compounds participate in an extensive hydrophobic network that restricts the protein's ability to form functional DNA-binding helix-turn-helix (HTH) motifs. Our studies also revealed a hitherto unsuspected structural plasticity of the HTH motif. In conclusion, we have designed 2-pyridone analogues that function as site-A selective PrfA inhibitors with potent antivirulence properties.
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