[Thermosensitive mutations of systems activating valine in E. coli].
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Bacterial Proteins↗
Biomedical subjects
M Yaniv
Publications and source records attributed to M Yaniv.
Induction of a factor that binds to the polyoma virus A enhancer on differentiation of embryonal carcinoma cells.
The cell type specificity of certain enhancers, competition experiments and the interactions that occur between proteins and enhancer sequences demonstrate that enhancers are the targets of specific factors involved in transcription control. The 246-base pair BclI-PvuII restriction enzyme fragment of polyoma virus has been shown to include two distinct enhancers, Py A and Py B, composed of several subdomains which interact with nuclear proteins from mouse fibroblasts. Embryonal carcinoma (EC) cells do not permit polyoma virus infection: both viral transcription and DNA replication are blocked. Host-range mutants of polyoma virus (EC mutants) capable of overcoming the expression block in EC cells have mutations or sequence rearrangements in their enhancer region. In an attempt to understand the molecular basis of this host restriction we compared the binding patterns displayed on the viral enhancer sequences by nuclear proteins prepared from EC cells or from fibroblasts. We show that one of the fibroblast factors required for Py A enhancer function, almost undetectable in EC cells, is induced after differentiation of these cells into parietal endoderm, suggesting that this protein is crucial in the regulation of viral gene expression during cellular differentiation, and perhaps more generally in the control of gene expression during early embryonic development.
Animals↗
Functional and radiographic outcome of juvenile osteochondritis dissecans of the knee treated with transarticular arthroscopic drilling.
Management of juvenile osteochondritis dissecans is controversial. The purpose of this study was to evaluate the functional and radiographic outcomes of transarticular arthroscopic drilling for isolated stable, juvenile osteochondritis dissecans lesions of the medial femoral condyle with an intact articular surface after 6 months of nonoperative management had failed. We reviewed 30 affected knees in 23 skeletally immature patients (mean age, 12.3 years; range, 8.5 to 16.1) at an average follow-up of 3.9 years (range, 2.0 to 7.2). Functional outcome was determined using the Lysholm score and radiographic outcome was determined using lesion size, and the radiographic score of Rodegerdts and Gleissner. There was significant improvement in the mean Lysholm score (from 58 to 93). There was significant improvement in the mean lesion size on anteroposterior (4.5 +/- 5.8 mm decrease) and lateral (8.4 +/- 8.1 mm decrease) radiographs. There was also significant improvement in the mean radiographic score (from 3.0 to 1.9). Radiographic healing was achieved in all patients at an average of 4.4 months after drilling (range, 1 to 11 months). Linear regression analysis revealed that younger age was an independent, multivariate predictor of Lysholm score improvement. There were no apparent surgical complications.
Adolescent↗