Antonio Rodríguez Torres

Evaluation of six serological tests in diagnosis and postoperative control of pulmonary hydatid disease patients

Latex agglutination (LA), passive hemagglutination (PHA), immunoelectrophoresis (IEP) and specific IgE, IgM, IgG enzyme-linked immunosorbent assay (ELISA) tests for diagnosis and postoperative follow-up of 79 patients with surgically confirmed pulmonary hydatidosis were evaluated. Specific IgG ELISA was the most sensitive test (83.5%) and the least sensitive tests were specific IgE ELISA (44.3%) and IEP (50.6%). The specificity obtained for all the serologic test was above 97% in all cases. The greatest number of false positives in all tests (except IEP) occurred in patients with Taenia saginata and Taenia solium cysticerci infestations and in patients with lymphoma and leukemia. Specific IgG ELISA demonstrated the highest negative predictive value (93.8%). No statistically significant differences (p > 0.050) were found in the sensitivity of the tests when patients with only one cyst and patients with various cysts were compared. Considering only the patients without relapse, the percentage of seropositive patients increased in all tests at 1 and 3 months after surgery. After that time the percentage of seropositive patients decreased. At 48 months after surgery all patients without relapse became negative in IEP, specific IgE ELISA, and specific IgM ELISA. The antibody titers in all seropositive patients increased during the 3 months after surgery. From these 3 months onward, antibody levels decreased in all serologic tests studied in the group of patients without relapse. The patients who had relapses during the first year after surgery presented persistently elevated antibody titers in all postoperative sera. The antibody titers of the patients who relapsed between the third and fourth years after surgery decreased progressively the third month after surgery, and increased in the serum obtained at the moment of relapse diagnosis. Our results show that persistence of elevated antibody titers in patients with pulmonary hydatidosis in the year after surgery or titer increase after a progressive decrease are indicative of relapse or reinfection.

Prevalencia de anticuerpos frente a Francisella tularensis en la población de Castilla y León con anterioridad a 1997

Fundamento y objetivos: Este trabajo pretende conocer la prevalencia de infeccion por Francisella tularensis en la poblacion de Castilla y Leon previa al brote de tularemia humana de finales de 1997. Sujetos y metodo: Se obtuvieron 4.825 sueros (entre abril de 1996 y abril de 1997) de residentes en Castilla y Leon. Se realizo una prueba de microaglutinacion en placa para detectar anticuerpos anti-F. tularensis. En los sueros positivos se llevaron a cabo seroaglutinaciones en tubo frente a Brucella, Yersinia enterocolitica y Proteus. Resultados: Se detectaron anticuerpos anti-F. tularensis en 9 (0,19%) de los 4.825 sueros. De esos 9 sueros, uno fue positivo en la seroaglutinacion frente a Brucella, siendo todos negativos frente a las otras bacterias. Conclusiones: Antes de 1997 la seroprevalencia de anticuerpos anti-F. tularensis en la poblacion de Castilla y Leon era baja (0,19%).

Comparative study of two methods for RNA extraction prior to detection of resistance to human immunodeficiency virus type 1 with the line probe assay

ABSTRACT We evaluated two methods from Roche and Promega for RNA extraction prior to the genotypic detection of human immunodeficiency virus type 1 resistance by line probe assay (LiPA). Fifty plasma RNA extracts were processed in parallel by LiPA. Results obtained by the Roche method were superior in the proportion of amplified samples, the percentage of mutated samples, and band intensity.