Inestabilidad microsatelital en neoplasias colorrectales / Microsatellite instability in colorectal neoplasms

La inestabilidad microsatelital (1M) es el defecto en la corrección del mal emparejamiento de secuencias cortas de bases (microsatélites) durante la replicación del ADN. La corrección está a cargo de un sistema de proteinas "mismatch repair" (MMR), codificadas por un grupo de genes cuyas mutaciones acrecientan la inestabilidad microsatelital e inician una neoplasia. El Cáncer Colónico Hereditario o Polipósico (CCHNP) o síndrome de Lynch: es el prototipo de neoplasia asociada a 1M. Existen 2 tipos de síndrome de Lynch, tipo I relacionado exclusivamente a cáncer colorectal y tipo II cáncer colorectal asociado a tumores extracolónicos Además existe un grupo de lesiones neoplásicas colónicas que presentan inestabilidad microsatelital sin estar asocíadas a CCHNP. Dentro de ellas se describen adenomas colorectales y pólipos hiperplásicos, con resultados controversiales en estos últimos.

Adaptation of the Medical Research Council Dyspnea Scale and the Oxygen Cost Diagram for its use in Puerto Rico

INTRODUCTION: Dyspnea is a common and disabling symptom for patients with chronic lung diseases. The Medical Research Council Dyspnea Scale (MRC) and the Oxygen Cost Diagram (OCD) are widely used instruments validated in English to measure breathlessness. OBJECTIVE: To translate and culturally adapt the MRC and the OCD for its use in Puerto Rico. METHOD: The scales were translated to Spanish and back translated. They were tested in patients attending a pulmonary clinic to assess its relevance and comprehension. Subjects answered the instruments, had a structured clinical interview and provided feedback. A multidisciplinary committee analyzed the source of misunderstanding using the input of the subjects, the clinical physicians, and the evaluators; made adjustments, and retested the instruments until inconsistencies were not observed. RESULTS: Placing emphasis on time spent walking instead of distance traveled improved the discrimination between grade two and three in the MRC. In the OCD, placing the activities to the right side eased the interpretation of the scale. Numerical symbols were eliminated to minimize discomfort in the severely impaired subjects reluctant to mark the line near zero. Reversing the order of both scales encouraged a thorough reading of the activities from minimal to high energy demanding eliciting a more fitting response compared to structured clinical interview especially in the severely ill patient. CONCLUSION: Using cross-cultural research methodologies to translate the MRC and OCD allowed the identification of differences in conceptualization when assessing the severity of dyspnea in Puerto Rico. Further testing is needed to confirm psychometric properties.

Rhabdoid tumor: an unusual pediatric brain tumor

Rhabdoid tumors of the brain are rare with an invariable dismal prognosis despite treatment. This is the case of a 3 year old boy who presented lethargy, somnolence, nausea, vomiting, and headaches one week prior to hospitalization. A posterior fossa tumor with hydrocephalus was noted on a head computed tomography (CT) scan. A ventriculoperitoneal shunt was placed with subsequent gross total tumor resection. Pathology findings were those of a rhabdoid tumor. The histopathology, immunohistochemistry and ultrastructure of this unusual pediatric cerebral neoplasia is discussed.

Experiencia en el tratamiento del carcinoma de las vías biliares / Experience in the treatment of carcinoma of the biliary tract

Se presenta una serie de 21 enfermos con tumores malignos de las vías biliares extrahepáticos. Se hace un análisis en los procedimientos diagnósticos y de la topografia de las lesiones. Se describen una variedad de operaciones y métodos que tienem como meta el alivio de la hiperbilirrubinemia y sus consecuencias. Se comparan nuestros resultados en relación a mortalidad y sobrevida con las series de autores extranjeros finalizando con una serie de recomendaciones y conclusiones que deben tomarse en cuenta para mejorar el prognóstico