Chemical fingerprint and source apportionment of PM2.5 in highly polluted events of southern Taiwan.

To investigate the spatial distribution and diurnal variation of the chemical composition of PM2.5 pollution in an industrial city of southern Taiwan, 12-h PM2.5 was diurnally continuously collected simultaneously at the Kaoping Air Quality Zone (KAQZ) during one highly PM2.5-polluted episode. Water-soluble ions, metallic elements, carbonaceous contents, dicarboxylic acids, and anhydrosugars were analyzed to characterize the chemical fingerprint of PM2.5. Backward trajectory simulation and chemical mass balance (CMB) receptor modeling were applied to identify the potential sources of PM2.5 and their contributions. It showed that Chaozhou (rural area) accompanying the highest SORs and NORs suffered from the most severe PM2.5 pollution during the episode. Sulfate (SO42-) was probably formed by the atmospheric chemical reaction in the daytime, while NO3- processed at nighttime at the KAQZ. A homogeneous formation of NO3- occurred at Chaozhou. The concentrations of Zn, Pb, Fe, Cu, V, and Al, mainly emitted from anthropogenic sources, increased significantly at the KAQZ. The highest OC, SOC/OC, and DA/OCs at Daliao (industrial area) were attributed to the transformation of primary VOCs to secondary OC via photo-oxidation during the episode. Oxalic acid was mainly produced through photochemical reactions since a high correlation between oxalic acid and Ca2+ was observed at Nanzi (urban area) and Daliao during the episode. During the episode, PM2.5 mostly originated from local primary or secondary aerosol than long-range overseas transport. The dominant source was anthropogenic emissions, accounting for 67.1% and 70.4% of PM2.5 at Nanzi and Daliao, respectively. At Chaozhou, the contribution of anthropogenic emissions was the lowest (42.4%), but secondary aerosols had the highest contribution of 38.3% of PM2.5 among the three areas during the episode.

Valproate is protective against 6-OHDA-induced dopaminergic neurodegeneration in rodent midbrain: A potential role of BDNF up-regulation.

BACKGROUND/PURPOSE: The main purpose of this study was to extend previously reported showing potent neuroprotective effect of valproic acid (VPA) in primary midbrain neuro-glial cultures to investigate whether VPA could protect dopamine (DA) neurons in vivo against 6-hydroxydopamine (6-OHDA)-induced neurodegeneration and to determine the underlying mechanism. METHODS: Male adult rats received a daily intraperitoneal injection of VPA or saline for two weeks before and after injection of 5, 10, or 15 µg of 6-OHDA into the brain. All rats were evaluated for motor function by rotarod performance. Brain samples were prepared for immunohistochemical staining and for determination of levels of dopamine, dopamine metabolites, and neurotrophic factors. RESULTS: 6-OHDA injection showed significant and dose-dependent damage of dopaminergic neurons and decrease of striatal dopamine content. Rats in the VPA-treated group were markedly protected from the loss of dopaminergic neurons and showed improvements in motor performance, compared to the control group at the moderate 6-OHDA dose (10 µg). VPA-treated rats also showed significantly increased brain-derived neurotrophic factor (BDNF) levels in the striatum and substantia nigra compared to the levels in control animals. CONCLUSION: Our studies demonstrate that VPA exerts neuroprotective effects in a rat model of 6-OHDA-induced Parkinson's disease (PD), likely in part by up-regulation BDNF.

Metallic characteristics of PM2.5 and PM2.5-10 for clustered Aeolian Dust Episodes occurred in an extensive fluvial basin during rainy season.

Aeolian dust episodes (ADEs) have been an emergency disaster in the Kaoping River Valley during the rainy season (May-September), which can severely deteriorate ambient particulate air quality in the region surrounding the Kaoping River. Thus, this study aims to characterize the metallic fingerprint of Aeolian dust (AD) and investigate the effects of ADEs on ambient particulate air quality along the Kaoping River Valley. Four manual sampling sites adjacent to the riverside were selected to collect fine (PM2.5) and coarse (PM2.5-10) aerosol samples during and after the ADEs in the periods of six events. A total of 13 metallic elements were analyzed using an inductively coupled plasma-atomic emission spectrometer. With metallic elements analysis and nonparametric statistical methods of Wilcoxon rank-sum test and Kruskal-Wallis test, this study successfully derived the metallic indicators of ADEs. The mass ratios of crustal elements (Fe, Ca, or Al) to reference element (Cd) obtained during the ADEs were much higher than those obtained after the ADEs. High mass ratios of Fe/Cd, Ca/Cd, and Al/Cd in PM2.5-10 were observed on the influenced areas of ADEs. Among them, (Fe/Cd)2.5-10 was proven as the best indicator which can be applied to effectively validate the existence of ADEs and evaluate their influences on ambient air quality. Moreover, PM2.5 concentrations during the ADEs were 3-3.6 fold higher than those after the ADEs. PM2.5 should be a contributor to AD, even though the mass ratios of PM2.5/PM10 ranged from 0.05 to 0.20 during the ADEs. Our findings provide valuable information regarding the characteristics of the AD during the ADEs in the Kaoping River. IMPLICATIONS: Indicators of (Fe/Cd)2.5-10 are approximately applied to observe the effects of ADEs. Local governments could realize the mechanisms of S- and NW-type aeolian dust episodes (ADEs). They can cause deterioration in different ways for the regional air quality surrounding Kaoping River Valley. Residents who have been living in the influenced areas can take precautions to prevent damage from aeolian dust. Strategies for curbing ADEs must reduce the area of bare lands by artificial measures in the long period of the sunny days during the rainy season. Future research should examine physical conditions of topsoils and other chemical composition in aeolian dust.

Homozygous ALDH2*2 Is an Independent Risk Factor for Ischemic Stroke in Taiwanese Men.

BACKGROUND AND PURPOSE: The *2 allele of the aldehyde dehydrogenase 2 gene (ALDH2) is the most common variant in Asian populations. The variant resulting in enzyme dysfunction was highly related to coronary artery disease. Recently, genome-wide association studies also discovered that the 12q24 locus near ALDH2 gene was associated with hypertension and ischemic stroke. This study intended to further investigate whether the above variant of ALDH2 increases the risk for ischemic stroke in Taiwanese. METHODS: A case-control study was conducted on 914 patients with acute ischemic stroke and 746 nonstroke controls. Polymerase chain reaction and sequencing were used to identify the ALDH2 genotype. Vascular risk factors, stroke subtypes, vascular stenosis, and stroke outcomes were analyzed. RESULTS: ALDH2 genotypes differed significantly between male controls (*1/*1 versus *1/*2 versus *2/*2=53.8% versus 39.9% versus 6.4%) and male patients with ischemic stroke (*1/*1 versus *1/*2 versus *2/*2=51.5% versus 37.3% versus 11.2%; P=0.048). No significant difference was found between groups for female patients (P=0.228). Multivariate logistic regression analysis revealed that the ALDH2*2/*2 genotype was an independent risk factor for ischemic stroke in male patients (odds ratio, 1.93 [95% confidence interval, 1.07-3.46]; P=0.028). Further analysis of men with ischemic stroke demonstrated that the polymorphism of ALDH2 was not related to vascular risk factors, severity of vascular atherosclerosis, stroke subtypes, and stroke functional outcomes. CONCLUSIONS: The study demonstrated that ALDH2*2/*2 may be an independent risk factor for ischemic stroke in Taiwanese men, but not in Taiwanese women.

Heavy binge drinking may increase risk of stroke in nonalcoholic hypertensives carrying variant ALDH2*2 gene allele.

PURPOSE: Epidemiologic evidence demonstrates that heavy drinking increases the risk of stroke. However, whether recent heavy drinking affects the incidence of acute stroke in nonalcoholic individuals with the variant allele ALDH2*2 has not been reported. CASE REPORT: Two previously nonalcoholic healthy men suffered from acute ischemic stroke after a single episode of binge drinking. Both patients had one risk factor for stroke (a history of hypertension) and were heterozygous for ALDH2*2. CONCULUSION: The confluence of these factors with stroke has raised the possibility that heavy binge drinking increases the risk of acute stroke in hypertensives with the variant ALDH2*2 gene allele.