Portable lactate analyzer for measuring lactate in cerebrospinal fluid (CSF) and plasma ? method-comparison evaluations / Analisador portátil para dosar lactato no líquido cefalorraquidiano e plasma ? comparação de método

Increased plasma lactate levels can indicate the presence of metabolic disorders in HIV infected individuals. Objective: To determine whether a portable analyzer is valid for measuring cerebrospinal fluid (CSF) and plasma lactate levels in HIV infected individuals. Method: CSF and plasma were collected from 178 subjects. Samples tested by the Accutrend® portable analyzer were compared to those tested by a reference device (SYNCHRON LX® 20). Results: The portable analyzer had in plasma sensitivity of 0.95 and specificity 0.87. For CSF the specificity was 0.95; the sensitivity 0.33; the negative predictive value was 95% and the positive predictive value 33%. Conclusions: These findings support the validity of the portable analyzer in measuring lactate concentrations in CSF that fall within the normal range. The relatively poor positive predictive value indicates that a result above the reference range may represent a “false positive test”, and should be confirmed by the reference device before concluding abnormality. .

O aumento da concentração plasmática dos níveis de lactato pode indicar a presença de distúrbios metabólicos em indivíduos infectados pelo HIV. Objetivo: Determinar a validade do analisador portátil para quantificar os níveis de lactato no líquido cefalorraquidiano (LCR) e plasma em indivíduos infectados. Método: LCR e plasma foram coletados de 178 participantes. As amostras testadas com o analisador portátil Accutrend® e os resultados comparados com aqueles obtidos com o equipamento de referência (SYNCHRON LX® 20). Resultados: O analisador portátil teve, no plasma, sensibilidade de 0,95 e especificidade 0,87. No LCR a especificidade foi 0,95; a sensibilidade 0,33; o valor preditivo negativo foi de 95% e o valor preditivo positivo 33%. Conclusões: Estes dados suportam a validade dos resultados do analisador portátil em concentrações de lactato dentro da faixa normal. Os valores preditivos positivos relativamente baixos indicam que um resultado acima da faixa de referência pode representar um resultado “falso positivo”. .

COMT Val158Met Polymorphism, Executive Dysfunction, and Sexual Risk Behavior in the Context of HIV Infection and Methamphetamine Dependence.

Catechol-O-methyltransferease (COMT) metabolizes prefrontal cortex dopamine (DA), a neurotransmitter involved in executive behavior; the Val158Met genotype has been linked to executive dysfunction, which might increase sexual risk behaviors favoring HIV transmission. Main and interaction effects of COMT genotype and executive functioning on sexual risk behavior were examined. 192 sexually active nonmonogamous men completed a sexual behavior questionnaire, executive functioning tests, and were genotyped using blood-derived DNA. Main effects for executive dysfunction but not COMT on number of sexual partners were observed. A COMT x executive dysfunction interaction was found for number of sexual partners and insertive anal sex, significant for carriers of the Met/Met and to a lesser extent Val/Met genotypes but not Val/Val carriers. In the context of HIV and methamphetamine dependence, dopaminergic overactivity in prefrontal cortex conferred by the Met/Met genotype appears to result in a liability for executive dysfunction and potentially associated risky sexual behavior.