Application of in vitro Myo-differentiation of non-muscle cells to enhance gene expression and facilitate analysis of muscle proteins.

Introduction of the myogenic-determination gene MyoD forces non-muscle cell cultures into myogenesis, thereby inducing expression of muscle-specific proteins and facilitating their analysis. In several MyoD-transfected fibroblasts, immunohistochemical detection showed expression of desmin after three days, of titin after five days and of dystrophin after seven days. Cell fusion (myotube formation) could be observed after five days. After nine days a fraction of the cells showed a striated titin pattern, indicating an advanced state of muscle differentiation. Dystrophin (the protein absent in Duchenne Muscular Dystrophy patients) can be detected in MyoD-transfected and differentiated fibroblasts from healthy individuals, and is absent in those of patients. MyoD-transfection increases transcription of the dystrophin gene, facilitating RNA-based mutation detection. Using RNA from MyoD-transfected, differentiated fibroblasts of a deceased patient with an unknown, non-deletion mutation, we were able to identify a CGA-->TGA nonsense mutation in the rod domain at basepair 6492 and to establish a rapid mutation specific test for future diagnosis of the mutation in his relatives.

Clinical diagnosis and changing manifestations of treponemal infection.

The symptomatology of the papillomas of yaws as described in the literature pertains to the disease in highly endemic areas only. Yaws with milder symptoms - attenuated yaws - occurs in areas that, possibly because of climatic influences, have a low endemicity of yaws. Receding yaws that follows mass treatment in previously highly endemic areas also has the features of attenuated yaws. Yaws symptomatology during the early papillomatous stage may assume any variation within two extreme clinical syndromes: holoendemic yaws, which is characterized by innumerable large, elevated, exuding papillomas of long duration (up to three years), relatively short latent periods, and high reagin levels; and attenuated yaws, which is characterized by scanty - or only one - small, dry papilloma(s) of short duration (only a few weeks), a dominance of latency, and low reagin levels. The public health importance of attenuated receding yaws lies in its potential to revert to classic yaws with high rates of transmission.

Methods for the surveillance of endemic treponematoses and sero-immunological investigations of "disappearing" disease.

Although the treatment of whole communities with long-acting penicillin for the control of endemic treponematoses of childhood during the past twenty years has led to a remarkable initial regression of disease, early clinical yaws has not yet been eliminated in large endemic areas and the elimination of early childhood syphilis has been observed in favourable environmental conditions in a single instance only. In most areas, transmission of infection continues at varying levels and recrudescence or periodic focal outbreaks continue to occur.Mass penicillin campaigns have been undertaken in 46 countries and up to the end of 1970 some 160 million people had been examined and some 50 million clinical cases, latent cases, and contacts had been treated. In the past few years, sero-epidemiological studies of the changing pattern of disease and infection have become possible and methods for long-term surveillance of endemic treponematoses have been developed. The application of these methods to the study of "disappearing" disease is described, particularly with regard to yaws but also to childhood syphilis and pinta.