Alexandre Gabriel Júnior

Validação laboratorial de um método automatizado de dosagem da atividade de adenosina desaminase em líquido pleural e em líquido cefalorraquidiano

OBJECTIVE The incidence of tuberculosis worldwide has emphasized the need for better assays designed to diagnose the disease, principally the extrapulmonary form. The objective of the present study was to validate the performance of an automated method for the determination of adenosine deaminase (ADA) activity in pleural fluid (PF) and cerebrospinal fluid (CSF), comparing it with a conventional method (the modified Giusti method). METHODS In total, 134 samples were selected from among those tested in our laboratory: 94 PF samples and 40 CSF samples. The ADA activity was determined using the two methods. Inter- and intra-assay precision was determined, linear regression analysis was performed, simple concordance tests were conducted, and the means of the differences were calculated. RESULTS The correlation coefficients for PF and CSF samples were, respectively, 0.96 and 0.95. Inter-assay precision was determined using 21 replicates at 3 different activity levels: low, medium and high. The percentage coefficient of variation (%CV) was, respectively, 5.9, 8.1 and 5.8 for PF samples, compared with 21.9, 18.6 and 13.8 for CSF samples. Intra-assay precision in %CV was 1.3 and 11.7, respectively, for PF and CSF samples. The concordance between the methods in PF and CRF samples was, respectively, 96.8% and 100%, considering the reference values for the diagnosis of TB to be 40 U/L (conventional) and 30 U/L (automated) in PF samples, versus 9 U/L (for both methods) in CSF samples. CONCLUSIONS The results validate the use of the automated method of determining ADA activity in PF and CSF samples as an alternative to the conventional method.

I Consenso Nacional para Padronização dos Laudos de FAN HEp-2

A analise da presenca de auto-anticorpos feita por imunofluorescencia indireta em celulas HEp-2 constitui-se em um metodo de triagem escolhido na maioria dos laboratorios clinicos. A ausencia de uma nomenclatura definida para a descricao dos laudos tem trazido problemas na utilizacao clinica do teste, pelas dificuldades no controle de qualidade e na padronizacao dos resultados, que, por sua vez, embora similares, recebiam denominacoes diferentes. O I Consenso Brasileiro para Padronizacao dos Laudos de FAN HEp-2 reuniu em agosto de 2000, em Goiânia, diversos especialistas de todo o Brasil. Esses emitiram pareceres em consenso para os distintos padroes: nucleares, nucleolares, citoplasmaticos e aparelho mitotico. Foram feitas recomendacoes sobre os criterios para a leitura de uma lâmina, bem como para relacao entre a diluicao de triagem e o sistema optico utilizado.

III Consenso Brasileiro para Pesquisa de Autoanticorpos em Células HEp-2: perspectiva histórica, controle de qualidade e associações clínicas

OBJETIVO: O III Consenso Brasileiro para Pesquisa de Autoanticorpos em Celulas HEp-2 (FAN) objetivou discutir estrategias para controlar a qualidade do ensaio, promover a atualizacao das associacoes clinicas dos diversos padroes e avaliar as dificuldades de implantacao do II Consenso ocorrido no ano de 2002. METODOS: Nos dias 13 e 14 de abril de 2007 participaram do encontro em Goiânia pesquisadores e especialistas de diversos centros universitarios e laboratorios clinicos de diferentes regioes do Brasil, com o proposito de discutir e aprovar as recomendacoes que visam a melhores padronizacao, interpretacao e utilizacao do ensaio pelos clinicos. Foram convidados como ouvintes representantes comerciais de diferentes empresas produtoras de insumos para realizacao do teste de FAN. RESULTADOS E CONCLUSAO: Dada a heterogeneidade de microscopios e reagentes disponiveis no mercado, o III Consenso enfatizou a necessidade do controle de qualidade em ensaios de imunofluorescencia indireta. Foram tambem feitas algumas adequacoes na terminologia utilizada para classificar os diferentes padroes. Finalmente, foi realizada uma atualizacao das associacoes clinicas com finalidade de facilitar cada vez mais o melhor uso do ensaio pelos clinicos.

Homocisteína plasmática total e fator von Willebrand no diabete melito experimental

OBJECTIVES: To determine the plasma homocysteine and von Willebrand factor levels as markers of endothelial dysfunction in rats with diabetes mellitus induced by streptozotocin. METHODS: Thirty-five adult male rats (Rattus norvegicus albinus) (weight between 180-200g) were randomized into three groups: control group (n=10), which received no drugs or vehicles; sham group (n=10), which received streptozotocin solution; and diabetic group (n=15), which received streptozotocin. Eight weeks after diabetes mellitus induction, the animals were weighed and anesthesized; blood samples were collected from abdominal aorta for plasma total homocysteine, von Willebrand factor and glucose levels. RESULTS: The experimental model was reproducible in 100% of animals. The mean plasma homocysteine levels were: 7.9 µmol/l (control), 8.6µmol/l (sham) and 6.1µmol/l (diabetic), with difference among the groups (p<0.01). Multiple comparison analysis among the groups showed that values in the diabetic group were lower than in the sham group (p<0.01). The mean von Willebrand factor values were 0.15 U/l (control), 0.16U/l (sham) and 0.18 U/l (diabetic), with difference among the groups (p=0.03). The mean value was higher in the diabetic group than in the control group (p<0.05). Correlation between homocysteine and von Willebrand factor was not observed in the diabetic group. CONCLUSION: Reduced homocysteine levels and increased von Willebrand factor levels were observed in diabetes mellitus induced by streptozotocin; nevertheless, there were no correlations between them and with final glucose levels.

Efeitos da pentoxifilina na anemia resistente à eritropoetina em pacientes sob hemodiálise

Anemia in end stage renal disease occurs due to the reduction in the production of erythropoietin caused by the decrease in functional renal mass. Erythropoietin has been indicated in the treatment of anemia however, about 5% of patients are resistant to this treatment. In erythropoietin resistance, it is necessary to increase the dosage to more than 12000 U/Kg/weekly, but even so the hematocrit target, which should remain between 33 and 36%, is not reached. Pro-inflammatory cytokines are significantly associated to resistance to erythropoietin treatment and so pentoxifylline is used to inhibit the production of these pro-inflammatory cytokines. This study was carried out with hemodialysis patients at the Ribamar Vaz Institute of Nephrology - in the Santa Casa de Misericordia Hospital of Maceio. Patients with diagnoses of resistance to erythropoietin received 400mg VO pentoxifylline after hemodialysis over a period of six months. The hematocrit and C-reactive protein (CRP) concentrations were analyzed three times: in the first month, at the end of three months (12 patients) and at the end of six months (7 patients). The mean CRP of the 12 patients in the first month was 5.65 and in the third month it was 2.58. However, in the sixth month, with the 7 patients remaining in the protocol, it was 4.55. No significant differences were observed. The final average hematocrit concentration of the patients was 28.74%. The average hematocrit concentration, in the six-month evaluation that preceded the project, was 26.22%. Statistically-relevant differences were not observed in the 12 patients followed up for 3 months or in the 7 that concluded the study. No correlations between the levels of CRP and hematocrit concentration were observed. However, in our sampling, the mean basal CRP was not high and this might have been an important factor to explain the difference between our results and other published reports. Thus, we conclude that there are no benefits with the use of pentoxifylline. However, further, more comprehensive studies are necessary in order to investigate the use of this drug as support in erythropoietin resistanc.