Catecolaminas vs. metanefrinas en el diagnóstico bioquímico de feocromocitoma y paraganglioma / Catecholamines vs. metanephrines in the biochemical diagnosis of pheochromocytoma and paraganglioma

RESUMEN Los tumores secretores de catecolaminas, feocromocitoma y paraganglioma son entidades poco frecuentes y potencialmente letales si no son diagnosticadas y tratadas a tiempo. El laboratorio cumple un rol fundamental en el diagnóstico y seguimiento de estos tumores a través de la evidencia bioquímica de un exceso de catecolaminas. Sin embargo, muchas veces suele ser dificultoso arribar a un diagnóstico temprano, debido a la baja incidencia de estos tumores y a la dificultad de hallar laboratorios con equipamiento especializado. El marcador bioquímico y las técnicas utilizadas para su medición han ido cambiando con el correr de los años. Tradicionalmente, la medición de catecolaminas en orina era la prueba bioquímica utilizada. Posteriores hallazgos de metabolitos aumentados en la orina de paciente llevaron al uso de ensayos colorimétricos para la detección de ácido vainillin mandélico y metanefrinas como marcadores diagnósticos adicionales de tumor. Las pruebas actuales para el diagnóstico bioquímico muestran una excelente precisión diagnóstica. La medición de metanefrinas libres de plasma utilizando cromatografía líquida de alta resolución con detección electroquímica o de espectrometría de masas en tándem proporciona la máxima precisión para el diagnóstico de estos tumores.

ABSTRACT Catecholamine-secreting neuroendocrine tumors called Pheochromocytoma and Paraganglioma are rare entities, but potentially lethal if diagnosis and treatment are not established early enough. Clinical Laboratory plays an important role in the diagnosis and follow-up of these tumors, through the biochemical evidence of a hyperproduction of catecholamines and its metabolites.

162 HIV-1 infected pregnant women and vertical transmission. Results of a prospective study.

BACKGROUND: Aim of this paper is to describe the changes over a 16-year period of the characteristics and management of HIV infected pregnant women. METHODS: Prospective study: analysis of data obtained from 162 women and 176 infants. Factors evaluated included: maternal socio-demographic level, immunological and virological parameters, antiretroviral therapy, mode of delivery, pregnancy outcome and babies follow-up. RESULTS: The proportion of women with heterosexual acquisition of infection has increased significantly from 13.5% in 1985-1989 to 47.1% in 1996-2001 (p<0.0005, Fisher's exact test), while the proportion acquiring HIV through injecting drugs has declined. Mean CD4 cell count at delivery was 535 x 106/l (+/-522.3 x 106/l). In 1990, 50% of mothers received antiretroviral therapy, rising significantly to 87.5% in 2000. The elective cesarean section was introduced in 1998 and its rate has increased to 75% in 2000. The vertical transmission rate changed from 9.5% in 1985-1989 to 14.3% in 1996-2000 (this difference was not statistically significant, Fisher's exact test). CONCLUSIONS: Social characteristics of the HIV-infected women have changed since the mid-1980s: in recent times women are having children at increasingly older ages and are more likely to know that they are HIV infected when they become pregnant. Antiretroviral therapy, elective caesarean delivery and avoidance of breastfeeding can reduce transmission of HIV, but the vertical transmission rate was unaffected by their use in our study and it remains high in comparison with rates reported from other studies.