biotimdase-deficient specimen in the autosampler. A sample cup containing phosphate buffer should be inserted between each sample suspected of having deficient or very low activity. Interfering substances such as sulfonamides, if present in a sample, can cause color development, such that a biotimdase-deficient specimen could exhibit color corresponding to normal activity and a normal specimen ...

Theory of mind requires an understanding of both desires and beliefs. Moreover, children understand desires before beliefs. Little is known about the mechanisms underlying this developmental lag. Additionally, previous neuroimaging and neurophysiological studies have neglected the direct comparison of these developmentally critical mental-state concepts. Event-related brain potentials were reco...

Young children show significant changes in their mental-state understanding as marked by their performance on false-belief tasks. This study provides evidence for activity in the prefrontal cortex associated with the development of this ability. Event-related brain potentials (ERPs) were recorded as adults (N = 24) and 4-, 5-, and 6-year-old children (N = 44) reasoned about reality and the beli...

OBJECTIVE To evaluate the prevalence of late HIV diagnosis (CD4<200 cell/mm³) in an HIV clinic in Mexico City between 2001-2008, to assess changes in this prevalence across the study period, and to determine the risk factors associated to late testing (LT). MATERIALS AND METHODS Cross-sectional analysis including all patients recently diagnosed as HIV. We estimated the proportion of LT patien...