Implications in the difference of anti-Mi-2 and -p155/140 autoantibody prevalence in two dermatomyositis cohorts from Mexico City and Guadalajara.

INTRODUCTION: Autoantibodies and clinical manifestations in polymyositis/dermatomyositis (PM/DM) are affected by both genetic and environmental factors. The high prevalence of DM and anti-Mi-2 in Central America is thought to be associated with the high UV index of the area. The prevalences of autoantibodies and the clinical manifestations of PM/DM were evaluated comparing two cohorts in Mexico. METHODS: Ninety-five Mexican patients with PM/DM (66 DM, 29 PM; 67 Mexico City, 28 Guadalajara) were studied. Autoantibodies were characterized by immunoprecipitation using 35S-methionine labeled K562 cell extract. Clinical information was obtained from medical records. RESULTS: DM represented 69% of PM/DM and anti-Mi-2 was the most common autoantibody (35%), followed by anti-p155/140 (11%); however, anti-Jo-1 was only 4%. The autoantibody profile in adult-onset DM in Mexico City versus Guadalajara showed striking differences: anti-Mi-2 was 59% versus 12% (P = 0.0012) whereas anti-p155/140 was 9% versus 35% (P = 0.02), respectively. A strong association of anti-Mi-2 with DM was confirmed and when clinical features of anti-Mi-2 (+) DM (n = 30) versus anti-Mi-2 (-) DM (n = 36) were compared, the shawl sign (86% versus 64%, P < 0.05) was more common in the anti-Mi-2 (+) group (P = 0.0001). Levels of creatine phosphokinase (CPK) were higher in those who were anti-Mi-2 (+) but they responded well to therapy. CONCLUSIONS: Anti-Mi-2 has a high prevalence in Mexican DM and is associated with the shawl sign and high CPK. The prevalence of anti-Mi-2 and anti-p155/140 was significantly different in Mexico City versus Guadalajara, which have a similar UV index. This suggests roles of factors other than UV in anti-Mi-2 antibody production.

Estudio descriptivo de la gutapercha PRODENT por medio de MEB y EDX in vitro / A descriptive study of the PRODENT gutta-percha by means of SEM and EDX: an in vitro study

El propósito de este estudio fue analizar la morfología y composición química de conos de gutapercha PRODENT por medio de MEB y EDX. Se incluyeron al azar 12 conos de gutapercha de calibres y lotes diferentes, los cuales se estudiaron del D1 al D16, seis conos de utilizaron para el estudio morfológico y el resto para microanálisis, el cual se realizó en la estructura interna y externa. La evaluación de la morfología reveló un alto grado de regularidad en las zonas estudiadas. El microanálisis evidenció que la capa externa está constituida por nueve elementos y la estructura interna por 11. Se encontró que dependiendo del calibre del cono, existe variabilidad en los elementos constitutivos, entre los cuales resaltan el zinc, oxígeno, bario y sodio. Bajo las condiciones de este estudio, concluimos que la gutapercha PRODENT ofrece características morfológicas y de composición química satisfactorias para su uso clínico