Environmental factors such as prenatal infection are involved in the pathogenic processes of neurodevelopmental psychiatric disorders. In the present study, we administered a viral mimic, polyriboinosinic-polyribocytidylic acid (poly I:C, 20 mg/kg, i.p.), to pregnant B6 mice at gestational day 9.5. Neonates born to these poly I:C-treated dams showed an increase of microglia in the hippocampus, indicating an activation of the immune system in the brains. Moreover, a significant increase in the number of dopamine-producing neurons in the ventral tegmental area was observed in adult male poly I:C offspring compared with age-matched saline offspring. Poly I:C offspring also exhibited hypolocomotor activity in a novel open-field arena but did not display signs of anxiety or depression in the elevated plus maze or the forced swim test, respectively. However, the short-term memory of the poly I:C offspring was impaired in a novel object recognition task. Therefore, the dendritic architecture of granule cells in the dentate gyrus (DG) and pyramidal neurons in the medial prefrontal cortex (mPFC) were examined. The dendritic complexity was reduced in the DG granule cells of the poly I:C offspring and exhibited shorter dendritic length compared with the saline offspring. The density of dendritic spines in the DG granule cells was also decreased in the poly I:C offspring. Furthermore, the dendritic complexity and spine density were reduced in layer II/III mPFC pyramidal neurons of the poly I:C offspring. Together, these data demonstrate impaired short-term memory and altered dendritic architecture in adult poly I:C offspring, which validates the prenatal infection paradigm as a model for neurodevelopmental psychiatric disorders.

We conducted this study to estimate residents' chronic hazard and carcinogenic risk in a groundwater-contaminated community after on-site remediation in Taiwan during 1999-2000. We followed guidelines for assessing hazardous waste sites of the U.S. Environmental Protection Agency (EPA) and used empirically measured contaminant levels and exposure parameters to perform health risk assessment on seven chlorinated hydrocarbons. We measured groundwater concentrations of vinyl chloride, tetrachloroethylene, trichloroethylene, 1,1-dichloroethylene, 1,1,1-trichloroethane, cis -1,2-dichloroethylene, and 1,1-dichloroethane in 49 off-site residential wells by gas chromatography/mass spectrometry. Exposure parameters were mainly derived from our field survey of 382 residents, and partially from U.S. EPA default values. Total exposure dose estimation included routes of inhalation during showering and dermal absorption of showers and other activities involved with hand-water contacts. The ingestion route of water was not included because most residents drank boiled water with negligible contaminants. We calculated a hazard index (HI) for all seven chlorinated hydrocarbons and carcinogenic risks for known human carcinogen of vinyl chloride and probable human carcinogens of tetrachloroethylene and trichloroethylene, which had the same target organ, the liver. The HI values for reasonable maximal exposure (RME) and average exposure were 14.3 and 0.2, respectively. The cancer risks based on RME and average exposure (in parentheses) for vinyl chloride, tetrachloroethylene, and trichloroethylene were 8.4 2 10 -6 (7.3 2 10 -9 ), 1.9 2 10 -4 (1.3 2 10 -7 ), and 1.4 2 10 -4 (1.2 2 10 -6 ), respectively. We applied Monte Carlo simulations to the sensitivity analysis, which showed that the contaminant levels, exposure duration, and time for showers were major determinants of health risks. We concluded that the contaminated groundwater was still unsafe for use even after the contaminated site underwent remediation by extraction and treatment in 1997.

♦ Background: This study compared the lifetime costs for peritoneal dialysis (PD) and hemodialysis (HD) patients in Taiwan.