Pyrethroid Pesticide Metabolite in Urine and Microelements in Hair of Children Affected by Autism Spectrum Disorders: A Preliminary Investigation.

The number of children affected by Autism Spectrum Disorders (ASD) is dramatically increasing as well as the studies aimed at understanding the risk factors associated with the development of ASD. Since the etiology of ASD is partly genetic and partly environmental, factors (i.e., heavy metals, pesticides) as well as lifestyle seem to have a key role in the development of the disease. ASD and Control (CTR) children, aged 5-12 years, were compared. Gas chromatography coupled with trap mass detector was used to measure the level of 3-PBA, the main pyrethroid metabolite in urine in a group of ASD patients, while optical emission spectrometry analysis was employed to estimate the level of metals and microelements in hair in a different group of ASD children. The presence of 3-PBA in urine seems to be independent of age in ASD children, while a positive correlation between 3-PBA and age was observed in the control group of the same age range. Urine concentration of 3-BPA in ASD children had higher values than in the control group, which were marginally significant (p = 0.054). Mg results were significantly decreased in ASD with respect to controls, while V, S, Zn, and Ca/Mg were marginally increased, without reaching statistical significance. Results of Principal Component (PC) analysis of metals and microelements in hair were not associated with either age or health status. In conclusion, 3-PBA in urine and Mg in hair were changed in ASD children relative to control ones.

Cationic and anionic polyelectrolyte complexes of xylan and chitosan. Interaction with lignocellulosic surfaces.

Cationic (CatPECs) and anionic (AnPECs) polyelectrolyte complexes from xylan and chitosan were formed, characterized and adsorbed onto unbleached fibers for improving the papermaking properties. They were prepared at a level of 30% of neutralization charge ratio by modifying the order of addition of polyelectrolytes and the ionic strength (0.01N and 0.1N NaCl). The charge density, colloidal stability and particle size of polyelectrolyte complexes (PECs) was measured using polyelectrolyte titration method, Turbiscan and Zetasizer Nano equipments, respectively. All the complexes were stable even after seven days from PEC formation. DRIFT spectra of complexes were also analyzed. The adsorption behavior of them onto cellulose nanofibrils model surfaces was studied using quartz crystal microbalance with dissipation monitoring, and surface plasmon resonance. It was found that the PEC layers were viscoelastic and highly hydrated. Finally, it is shown that the adsorbed PECs onto cellulosic fibers markedly improved the tensile and crushing strengths of paper.