Essential regulatory elements for NHE3 gene transcription in renal proximal tubule cells

The objectives of the present study were to identify the cis-elements of the promoter absolutely required for the efficient rat NHE3 gene transcription and to locate positive and negative regulatory elements in the 5’-flanking sequence (5’FS), which might modulate the gene expression in proximal tubules, and to compare this result to those reported for intestinal cell lines. We analyzed the promoter activity of different 5’FS segments of the rat NHE3 gene, in the OKP renal proximal tubule cell line by measuring the activity of the reporter gene luciferase. Because the segment spanning the first 157 bp of 5’FS was the most active it was studied in more detail by sequential deletions, point mutations, and gel shift assays. The essential elements for gene transcription are in the region -85 to -33, where we can identify consensual binding sites for Sp1 and EGR-1, which are relevant to NHE3 gene basal transcription. Although a low level of transcription is still possible when the first 25 bp of the 5’FS are used as promoter, efficient transcription only occurs with 44 bp of 5’FS. There are negative regulatory elements in the segments spanning -1196 to -889 and -467 to -152, and positive enhancers between -889 and -479 bp of 5’FS. Transcription factors in the OKP cell nuclear extract efficiently bound to DNA elements of rat NHE3 promoter as demonstrated by gel shift assays, suggesting a high level of similarity between transcription factors of both species, including Sp1 and EGR-1.

Síndrome do túnel do tarso: relato de 11 casos / Tarsal tunnel syndrome: report of 11 cases

Na atualidade, apesar de pouco conhecida, a síndrome do túnel do tarso, pelos recursos eletroneurofisiológicos e de imagem, se impoe no diagnóstico diferencial das patologias que determinem sintomas álgicos nos pés. Objetivo. Sao apresentados e discutidos pacientes com queixa de dor nos pés cujo quadro clínico permitiu o diagnóstico de síndrome do túnel do tarso. MÉTODOS. Onze pacientes foram submetidos e exame eletroneuromiográfico conclusivo de compressao nervosa e, em seguida, foram submetidos a cirurgia específica, quando foi feita a descompressao do túnel do tarso pela secçao do retináculo dos flexores. Resultados. Nos casos apresentados, importante espessamento fibroso foi observado na maioria dos casos, e a melhora da sintomatologia dolorosa foi verificada nas primeiras semanas do pós-operatório, sendo os pacientes observados por intervalo de 3 meses a 5 anos, nao apresentando recorrência do quadro de dor.