Transcription of T7 and mutant T3 DNA during infections of F plasmid-containing cells has been analyzed by using Southern hybridization. A transcriptional defect is apparent in these abortively infected cells that is most severe in the class III region of the phage genome. In particular, RNAs that are initiated from the gene 13 promoter are not elongated to give full-length molecules. It is sug...

Familial patterns of the occurrence of breast cancer were studied in a population-based case-control series of black women from the Cancer and Steroid Hormone study. The risks of breast cancer among relatives of breast cancer cases were compared to those of controls who were matched for age and locale. Using the term "proband" to indicate either case or control status, significant predictors of...