Drug dosing using estimated glomerular filtration rate: Misclassification due to metamizole interference in a creatinine assay.

BACKGROUND: The estimated glomerular filtration rate is a rather important measurement for patients under intensive care, since they often receive several drugs, and impaired renal function may result in misleading dosing. The estimated glomerular filtration is derived from mathematical models using serum creatinine, a measurement that suffers interference of some drugs, such as metamizole. This study intended to evaluate the impact on patient stratification for dose adjustment of two antimicrobials (meropenem and vancomycin) caused by metamizole interference in creatinine measurement by dry chemistry. METHODS: A cross-sectional study was conducted with a group of 108 hospitalized patients under metamizole prescriptions at fixed intervals. Serum creatinine concentrations were determined by enzymatic dry chemistry and Jaffé assays, and the estimated glomerular filtration rate was calculated through the CKD-EPI equation. Patients were stratified in groups according to their estimated glomerular filtration rate for drug dosing of vancomycin and meropenem. RESULTS: Creatinine values were significantly lower in measurements performed by the dry chemistry method in comparison to Jaffé assay (P < 0.0001) when patients are under metamizole treatment. A significant bias (-40.3%) was observed between those two methods, leading to a significant difference (P < 0.0001) in patient classification according to renal function using the CKD-EPI equation for dosing adjustment. CONCLUSIONS: During the validity of metamizole treatment, the stratification for drug dosing by the estimated glomerular filtration rate is not reliable if the creatinine measurement is done through dry chemistry. Clinical and laboratory staff must be aware of these limitations and cooperate to optimize pharmacotherapy.

Pesquisa de marcadores sorológicos para doença celíaca nos doadores de sangue da cidade de Ponta Grossa - Paraná - Brasil / Search serological markers for celiac disease in blood donors in the city of Ponta Grossa - Paraná - Brazil

A Doença Celíaca é uma patologia autoimune, caracterizada por lesões na mucosa do intestino delgado, em indivíduos geneticamente predispostos, desencadeada pela ingestão de glúten. Além dos fatores genéticos, a presença de fatores ambientais e imunológicos contribui para o desenvolvimento da doença. Portadores desta patologia não podem realizar doação de sangue por esta ser considerada uma doença autoimune. Objetivos: determinar a prevalência do anticorpo antitransglutaminase associado à doença celíaca em candidatos a doadores de sangue. Método: o desenho foi descritivo do tipo corte transversal, com a participação de 300 candidatos a doadores de sangue, residentes na cidade de Ponta Grossa, com idade entre 18 e 65 anos. Todos os participantes responderam a um questionário a respeito da presença de diarreia, constipação e dor abdominal nos três meses que antecederam a doação. A dosagem do anticorpo antitransglutaminase tecidual IgA foi realizada em todos os indivíduos pela metodologia ELISA, e àqueles com teste positivo foram convidados a realizar biópsia de intestino delgado por endoscopia digestiva alta. Resultados: em um total de 300 candidatos a doadores de sangue foram encontrados três casos positivos, com confirmação em triplicata do teste de antitransglutaminase IgA. Conclusão: a pesquisa precoce de doença celíaca é uma questão de prevenção na Saúde Pública, visto que casos não diagnosticados tendem a evoluir para complicações graves, o que gerariam custos elevados e desnecessários ao sistema público e privado de saúde.

Celiac disease is an autoimmune disease characterized by lesions on the small intestine mucosa in genetically predisposed individuals, triggered by gluten ingestion. Besides genetic factors, presence of environmental and immunological factors contribute to the development of the disease. Patients with this condition cannot donate blood, as this is considered an autoimmune disease. Objectives: establish prevalence of antitransglutaminase associated with celiac disease in prospective blood donors. Methods: the design was cross-sectional escriptive involving 300 prospective blood donors resident in the city of Ponta Grossa, aged between 18 and 65 years. All participants answered a questionnaire about the presence of diarrhea, onstipation and abdominal pain within three months previous to donation. The dosage of IgA tissue transglutaminase antibody was performed in all subjects by ELISA methodology, and those testing positive were invited to perform small intestine biopsies by endoscopy. Results: in a total of 300 prospective blood donors, there were three (3) positive cases with confirmation in triplicate test of transglutaminase IgA. Conclusions: early celiac cisease scanning is a matter of prevention in Public Health, as undiagnosed cases tend to progress to serious complications that generate high and unnecessary costs to the public and private health systems.

5-Lipoxygenase plays a role in the control of parasite burden and contributes to oxidative damage of erythrocytes in murine Chagas' disease.

Chagas' disease is accompanied by severe anemia and oxidative stress, which may contribute to mortality. In this study, we investigated the role of 5-lipoxygenase (5-LO) in the control of parasitism and anemia associated with oxidative damage of erythrocytes in experimental Trypanosoma cruzi infection. Wild-type C57BL/6, 129Sv mice treated or not with nordihydroguaiaretic acid (NDGA, 5-LO inhibitor), mice lacking the 5-LO enzyme gene (5-LO(-/-)) and inducible nitric oxide synthase gene (iNOS(-/-)) were infected with the Y strain of T. cruzi. Impairment of 5-LO resulted in increased numbers of trypomastigote forms in the blood and amastigote forms in the heart of infected mice. We assessed oxidative stress in erythrocytes by measuring oxygen uptake, induction time and chemiluminescence following treatment with tert-butyl hydroperoxide (TBH). Our results show that 5-LO metabolites increased lipid peroxidation levels in erythrocytes during the early phase of murine T. cruzi infection. NDGA treatment reduced oxidative damage of erythrocytes in C57BL/6 T. cruzi-infected mice but not in C57BL/6 iNOS(-/-) infected mice, showing that the action of NDGA is dependent on endogenous nitric oxide (NO). In addition, our results show that 5-LO metabolites do not participate directly in the development of anemia in infected mice. We conclude that 5-LO products may not only play a major role in controlling heart tissue parasitism, i.e., host resistance to acute infection with T. cruziin vivo, but in the event of an infection also play an important part in erythrocyte oxidative stress, an NO-dependent effect.