High levels of arsenic are found in the soil and water of the Second Region in Chile as a result of natural causes. Total and inorganic arsenic contents were analyzed in the edible part of 16 agricultural products (roots, stems, leaves, inflorescences, and fruits) grown in this area. The total arsenic contents varied in the range 0.008-0.604 microg g(-1) of wet weight (ww), below the maximum level allowed by Chilean legislation (1 microg(-1) of ww). Inorganic arsenic contents (range = 0.008-0.613 microg(-1) of ww) represented between 28 and 114% of total arsenic. The concentrations of total and inorganic arsenic found in edible roots and leaves were higher than those found in fruit. The highest concentrations were found in a sample of spinach. High quantities of this vegetable would have to be consumed (250 g/day) to reach the Provisional Tolerable Weekly Intake for inorganic arsenic. The vegetable group may make a considerable contribution to the total intake of inorganic arsenic.

Total and inorganic As contents of cooked vegetables obtained from an arsenic endemic area of Chile were analyzed. Inorganic As intake from those foods, bread, and water was estimated. The study was performed in two different periods, in which the water used by the population for drinking and cooking purposes contained 0.572 (first period) or 0.041 microg mL(-)(1) (second period). In the first period, the FAO/WHO reference intake was exceeded by all of the persons interviewed. In the second period, the reference intake was exceeded by all of the persons interviewed ages 13-15. The foods studied contributed 4% (first period) or 25% (second period) of the inorganic As intake. The results show the contribution of food to inorganic As intake and the risk to which those ages 15 or younger are exposed.

Measurement of dynamic cerebral autoregulation (CA), the transient response of cerebral blood flow (CBF) to changes in arterial blood pressure (ABP), has been performed with an index of autoregulation (ARI), related to the parameters of a second-order differential equation model, namely gain (K), damping factor (D) and time constant (T). Limitations of the ARI were addressed by increasing its numerical resolution and generalizing the parameter space. In 16 healthy subjects, recordings of ABP (Finapres) and CBF velocity (ultrasound Doppler) were performed at rest, before, during and after 5% CO(2) breathing, and for six repeated thigh cuff maneuvers. The unconstrained model produced lower predictive error (p < 0.001) than the original model. Unconstrained parameters (K'-D'-T') were significantly different from K-D-T but were still sensitive to different measurement conditions, such as the under-regulation induced by hypercapnia. The intra-subject variability of K' was significantly lower than that of the ARI and this parameter did not show the unexpected occurrences of zero values as observed with the ARI and the classical value of K. These results suggest that K' could be considered as a more stable and reliable index of dynamic autoregulation than ARI. Further studies are needed to validate this new index under different clinical conditions.