Digit Ratio (2D:4D) in Newborns: Influences of Prenatal Testosterone and Maternal Environment

Introduction: The 2D:4D digit ratio is sexually-dimorphic, probably due to testosterone action through the perinatal period. We characterize the 2D:4D ratio in newborn (NB) infants, in between the pre- and postnatal surges of testosterone, and relate it to the mother's 2D:4D and to testosterone levels in the amniotic fluid (AF). Subjects and methods: Testosterone was assayed in samples of maternal plasma and AF collected at amniocentesis. Shortly after birth, 106 NBs and their mothers were measured for 2D:4D ratio. Results: NB males had lower mean 2D:4D ratios than females but this dimorphism was significant only for the left hand (males: 0.927; females: 0.950; p=0.004). Mothers who had sons had lower 2D:4D ratios than those who had daughters and the mother's 2D:4D were higher than those of NBs regardless of sex. Both hands of NB females were negatively correlated with AF testosterone and positively correlated with the mother's 2D:4D, but males showed no significant associations. Maternal plasma testosterone also showed a negative weak correlation with NB's digit ratio in both sexes. Conclusions: Sexual dimorphism at birth was only significant for the left hand, in contrast with reports of greater right hand dimorphism, suggesting that postnatal testosterone is determinant for 2D:4D stabilization. The lower 2D:4D ratios in mothers who had sons support claims that hormone levels in parents are influential for determining their children's sex. NB female's digit ratio, but not males', was associated to the level of AF testosterone. The mother's 2D:4D ratios were positively correlated with their daughters' 2D:4D, but the same was not observed for male NBs, suggesting that prenatal testosterone levels in male fetus lead their 2D:4D ratios to stray from their mothers' with high individual variability.

Renal Replacement Therapy in Critically Ill Patients - What Modality Should We Choose?

A lesão renal aguda é uma complicação comum nas unidades de cuidados intensivos. A mortalidade do doente crítico que requer diálise é extremamente elevada, apesar dos avanços significativos dos cuidados prestados a estes doentes. Há várias décadas que se discute o tipo de modalidade dialítica a oferecer a estes doentes (continua ou intermitente) e os principais fatores que pesam na decisão clínica são os meios e a experiência do centro, bem como a condição clínica do doente. Vários estudos tentaram estabelecer a melhor abordagem ao doente crítico com lesão renal aguda e necessidade dialítica, em termos de sobrevida do doente e recuperação renal. Nesta revisão tentarei resumir as evidências disponíveis sobre este tema.