RESUMEN
OBJECTIVES: (1) To develop a scale that is useful in evaluating the accuracy of multifrequency bioelectrical impedance analysis (MF-BIA) in the assessment of body water volumes against the accepted gold standard measurements based on isotope-dilution and total body potassium (TBK). (2) To perform a pilot test of the scale. DESIGN: A scale was developed to evaluate the accuracy of MF-BIA in the assessment of body water volumes. Questions were obtained from reading the scientific literature and discussions involving the four authors. Three of these and two additional independent readers pre-tested the scale. A weighting was identified for each question and a pilot test with a sample of 10 articles (different to those used for the questionnaire performance) was conducted. A further validation was carried out with a second set of 20 articles and two additional independent readers. RESULTS: The kappa statistic expressing the level of agreement between pairs of the first three authors using this scale with 10 articles, was 0.3, 0.4 and 0.6 after the first attempt. A second evaluation after specific changes improved the agreement to 0.8, 0.6 and 0.8. The mean score for 10 articles was 252+/-36 points from a total score of 400 (63+/-9%). The evaluation with the second set of 20 articles resulted in a kappa of 0.7 from two pairs of authors. The evaluation with two additional reviewers resulted in a kappa=0.7. CONCLUSION: A tool has been developed to assess the accuracy of the MF-BIA technique and to identify methodological components, plan future studies and critically evaluate data in this area. It is likely that this tool may also be used to assess the accuracy of single frequency studies.
Asunto(s)
Agua Corporal/fisiología , Potasio/fisiología , Proyectos de Investigación , Impedancia Eléctrica , Humanos , Proyectos Piloto , Técnica de Dilución de Radioisótopos , Sensibilidad y Especificidad , Encuestas y CuestionariosRESUMEN
An improved and simplified method of genotyping was developed for classifying hepatitis C virus (HCV) isolates into the five common genotypes, i.e., I/1a, II/1b, III/2a, IV/2b, and V/3a, by PCR with genotype-specific primers deduced from the core gene. Sense and antisense primers, specific for each of the five common genotypes, were designed by comparison of 319 core gene sequences from HCV isolates of various genotypes from genetic groups 1 to 9. In the first round of PCR, a sequence of 433 bp representing nucleotides 319 to 751 was amplified with universal primers. The second round of PCR was performed with respective sense and antisense primers in two separate reactions, one for the amplification of genotypes I/1a and II/1b and the other for the amplification of genotypes III/2a, IV/2b, and V/3a. The specificity of genotyping was confirmed with a panel of 191 serum samples containing HCV isolates whose core gene sequences were known: 110 serum samples infected with HCV of the five common genotypes and 81 serum samples infected with HCV of other genotypes. The use of sense and antisense primers for genotype II/1b (primers 389 and 492) abolished the cross-reaction of the antisense primer for genotype II/1b (primer 133) with some HCV isolates of genotype I/1a found by our original method. The new method was used for genotyping 130 HCV isolates from Spain, 53 from Brazil, 106 from China, and 30 from Macau. A total of 329 bp of the NS5b region (nucleotides 8279 to 8607) of five isolates from Spain and five isolates from Macau which could not be classified as any of the five common HCV genotypes or genotype 2c were sequenced, and the sequences were compared with those of HCV isolates of known genotypes; two isolates from Spain were deduced to be of genotype 4d and one was deduced to be of genotype 1d, while the remaining two isolates from Spain had novel genotypes in genetic group 2; however, all five isolates from Macau were of genotype 6a.
Asunto(s)
ADN Viral/análisis , Hepacivirus/aislamiento & purificación , Brasil , China , Genotipo , Hepacivirus/genética , Macao , Datos de Secuencia Molecular , EspañaRESUMEN
Testing of paired serum samples of 12 children with the Wiskott-Aldrich syndrome for the presence of hepatitis B surface antigen (HBsAg) antibody to HB, Ag, and antibody to the hepatitis B core antigen revealed evidence of hepatitis B virus infection in three. None of the three, however, developed overt clinical hepatitis or the chronic HBsAg carrier state. These data suggest that the immunologic defects seen in the Wiskott-Aldrich syndrome permit adequate immune responses to the hepatitis B virus and do not predispose to the chronic HBsAg carrier state.