Biological activity of peptide-conjugated polyion complex matrices consisting of alginate and chitosan.

Peptide-conjugated polysaccharide matrices using bioactive laminin-derived peptides are useful biomaterials for tissue and cell engineering. Here, we demonstrate an easy handling preparation method for peptide-polysaccharide matrices using polyion complex with both alginate and chitosan. First, aldehyde-alginate was synthesized by oxidization of alginate using NaIO4 , and then, reacted with Cys-peptides. Next, the peptide-alginate solution was added to a chitosan-coated plate, and the peptide-polyion complex matrices (peptide-PCMs) were prepared. The peptide-PCMs using an integrin αvß3-binding peptide (A99a: ALRGDN, mouse laminin α1 chain 1145-1150) and an integrin α2ß1-binding peptide (EF1XmR: RLQLQEGRLHFXFD, X = Nle, mouse laminin α1 chain 2751-2763) showed strong cell attachment activity in a dose-dependent manner. When we examined the effect of various spacers on the biological activity of A99a-PCM, hydrophobic and long spacers enhanced the cell attachment activity. Further, the A99a-PCM with the spacers strongly promoted neurite outgrowth. The polyion complex method is an easy way to obtain insolubilized matrix and is widely applicable for various polysaccharides. The peptide-PCM is useful as a biomaterial for cell and tissue engineering.

Prenatal exposure to organophosphate pesticides and neurobehavioral development of neonates: a birth cohort study in Shenyang, China.

BACKGROUND: A large amount of organophosphate pesticides (OPs) are used in agriculture in China every year, contributing to exposure of OPs through dietary consumption among the general population. However, the level of exposure to OPs in China is still uncertain. OBJECTIVE: To investigate the effect of the exposure to OPs on the neonatal neurodevelopment during pregnancy in Shenyang, China. METHODS: 249 pregnant women enrolled in the Central Hospital Affiliated to Shenyang Medical College from February 2011 to August 2012. A cohort of the mothers and their neonates participated in the study and information on each subject was obtained by questionnaire. Dialkyl phosphate (DAP) metabolites were detected in the urine of mothers during pregnancy to evaluate the exposure level to OPs. Neonate neurobehavioral developmental levels were assessed according to the standards of the Neonatal Behavioral Neurological Assessment (NBNA). Multiple linear regressions were utilized to analyze the association between pregnancy exposure to OPs and neonatal neurobehavioral development. RESULTS: The geometric means (GM) of urinary metabolites for dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP), diethyl phosphate (DEP), and diethyl thiophosphate (DETP) in pregnant women were 18.03, 8.53, 7.14, and 5.64 µg/L, respectively. Results from multiple linear regressions showed that prenatal OP exposure was one of the most important factors affecting NBNA scores. Prenatal total DAP concentrations were inversely associated with scores on the NBNA scales.?Additionally, a 10-fold increase in DAP concentrations was associated with a decrease of 1.78 regarding the Summary NBNA (95% CI, -2.12 to -1.45). And there was an estimated 2.11-point difference in summary NBNA scores between neonates in the highest quintile of prenatal OP exposure and the lowest quintile group. CONCLUSION: The high exposure of pregnant women to OPs in Shenyang, China was the predominant risk factor for neonatal neurobehavioral development.