Polyclonality among clinical strains of non-pigmented rapidly growing mycobacteria: phenotypic and genotypic differences and their potential implications.

To investigate the potential implications (especially the implications in clinical significance and antimicrobial susceptibility) of polyclonality among rapidly growing mycobacteria, we performed random amplified polymorphic DNA analysis in 64 clinical isolates of which the clinical significance was established. Phenotypic characteristics (antimicrobial susceptibility test, colony morphology and growth rate) of each clone were studied. Polyclonality was detected in 13 of the isolates (20.3%). There was a relationship between monoclonality and clinical significance (p 0.0096). Monoclonal and polyclonal isolates showed different behaviour in antimicrobial susceptibility. There was a strong relationship between monoclonality and those species that are more pathogenic for humans, and also with clinical significance of the isolates.

[Ocular retention in patients with uveal melanoma managed by a multimodality approach]. / Estudio de la conservación del globo ocular con un abordaje multiterapéutico en el melanoma uveal.

OBJECTIVE: to analyze ocular survival in eyes with uveal melanoma treated with conservative therapies, in a centre that applies all treatment modalities. METHODS: Patients diagnosed with uveal melanoma and treated between September 1990 and April 2007 were included in an historical cohorts study. RESULTS: 273 patients were included. 193 were treated with conservative treatments (70.69%) and 80 were enucleated as primary treatment. 14 patients were enucleated after conservative treatment (7.2%). Kaplan-Meier survival analysis showed an 88% survival probability of the eye in the first 5 years after conservative treatment and 83% at 10 years. CONCLUSIONS: Conservative treatments for uveal melanoma, especially brachitherapy, are safe and effective in relation to tumor control and rate of secondary effects.

Dosimetric study of the 15 mm ROPES eye plaque.

The main aim of this paper is to make a study of dose-rate distributions obtained around the 15 mm, radiation oncology physics and engineering services, Australia (ROPES) eye plaque loaded with 125I model 6711 radioactive seeds. In this study, we have carried out a comparison of the dose-rate distributions obtained by the algorithm used by the Plaque Simulator (PS) (BEBIG GmbH, Berlin, Germany) treatment planning system with those obtained by means of the Monte Carlo method for the ROPES eye plaque. A simple method to obtain the dose-rate distributions in a treatment planning system via the superposition of the dose-rate distributions of a seed placed in the eye plaque has been developed. The method uses eye plaque located in a simplified geometry of the head anatomy and distributions obtained by means of the Monte Carlo code GEANT4. The favorable results obtained in the development of this method suggest that it could be implemented on a treatment planning system to improve dose-rate calculations. We have also found that the dose-rate falls sharply along the eye and that outside the eye the dose-rate is very low. Furthermore, the lack of backscatter photons from the air located outside the eye-head phantom produces a dose reduction negligible for distances from the eye-plaque r<1 cm but reaches up to 20% near the air-eye interface. Results showed that the treatment planning system lacks accuracy around the border of the eye (in the sclera and the surrounding area) due to the simplicity of the algorithm used. The BEBIG treatment planning system uses a global attenuation factor that takes into account the effect of the eye plaque seed carrier and the lack of backscatter photons caused by the metallic cover, which in the case of a ROPES eye plaque has a default value of T= 1 (no correction). In the present study, a global attenuation factor T=0.96 and an air-interface correction factor which improve on treatment planning system calculations were obtained.