Investigation of Borrelia spp. in ticks (Acari: Ixodidae) at the border crossings between China and Russia in Heilongjiang Province, China

OBJECTIVE@#To investigate the precise species of tick vector and the Borrelia spirochete pathogen at the Heilongjiang Province international border with Russia.@*METHODS@#In this study, ticks were collected from 12 Heilongjiang border crossings (including grasslands, shrublands, forests, and plantantions) to determine the rate and species type of spirochete-infected ticks and the most prevalent spirochete genotypes.@*RESULTS@#The ticks represented three genera and four species of the Ixodidae family [Ixodes persulcatus, Dermacentor silvarum, Haemaphysalis concinna and Haemaphysalis japonica]. Ixodes persulcatus had the highest amount of Borrelia burgdorferi sensu lato infection of 25.6% and the most common species of Borrelia isolated from Ixodes persulcatus was Borrelia garinii, strain PD91.@*CONCLUSIONS@#Our results suggest that Borrelia garinii PD91-infected Ixodes persulcatus may be the principal cause of Lyme disease in the border crossing areas of Heilongjiang Province.

Exposure to environmental hexachlorocyclohexane (HCH) and dichlorodiphenyltrichloroethane (DDT) among rural children in north eastern China / 生物医学与环境科学（英文）

<p><b>OBJECTIVE</b>To assess HCH and DDT exposure levels and associated risk factors among 262 children aged 6-10 years in a northeastern rural area of China between April and May of 2008.</p><p><b>METHODS</b>Eight HCH and DDT metabolites in serum samples were monitored by gas chromatography. A questionnaire was administered to identify the sources of pesticides in children' serum samples.</p><p><b>RESULTS</b>At least one pesticide metabolite was detected in 81.7% of the tested children. Higher amounts of pp'DDD were detected in 50% of them. Children's age and their father's occupation as farmers, together with not changing work clothes after work, were the main risk factors for HCH and DDT exposure among them.</p><p><b>CONCLUSION</b>Children living in rural areas are experiencing multiple sources of organochlorine pesticide exposure. These pesticides may have been retained in the environment for a long period of time.</p>

Effects of aluminum on the intracellular calcium concentration and the expression of calcium channels in the hippocampus of rats / 中国地方病学杂志

Objective To dynamically investigate the effects of aluminum on the concentration of free intracellular Ca2+([Ca2+]i) and the expression of calcium channels in the hippocampus of rats. Methods Healthy 64 Wistar rats were taken as the experimental objects. And these rats were randomly divided into 16 groups according to their weights, and were instilled with AlCl3 at 0(control),37.3,74.7 and 248.7 mg/kg respectively. The experimental time exposed to AlCl3 was 45,75,120 d, among which the rats were given AlCl3 for 120 d fed normally for 30 d. The hippoeampus were segregated on day 45,75,120 and 150 d and the[Ca2+]i of hippocampus of rats were detected by fluorospectrophotometer. The expression of Ryanodine receptor 2 (RyR2) mRNA and α1C ubunit of L-type calcium ehannels(L-Ca2+α1C) mRNA were detected by RT-PCR analysis. Results [Ca2+]i was increased by AlCl3 in a dose-and time-dependant manner(F=23.136 and 19.089, P<0.01). There was a synergistic effect between the dose and time in [Ca2+]i (F=2.270, P<0.05). In time of 120,150 days, the [Ca2+]i of rats hippocampus in 37.3[(299.3±48.7), (342.7±35.3)nmol/L], 74.7[(391.2±47.9), (408.1±42.8)nmol/L] and 248.7 mg/kg group[(397.9±55.8), (405.2±22.7)nmol/L] significantly increased compared with control group [(195.1±29.9), (209.1±30.6)nmol/L; P<0.01]. The expression of RyR2 mRNA and L-Ca2+α1C mRNA were increased by AlCl3(F=23.301 and 60.812, P<0.01). The experimental time could lower the expression of L-Ca2+ α1C mRNA (F=6.088, P<0.01), but had no influences on the expression of RyR2 mR NA (F=1.361, P>0.05). There was interaction between the dose of AlCl3 and the time in the expression of L-Ca2+α1C mRNA (F=5.876,P< 0.01). On day 75,120 and 150 of the experiment, the expression of L-Ca2+α1C mRNA in rat hippocampus of 74.7 (1.03±0.16,1.18±0.18,0.92±0.11) and 248.7 mg/kg group(1.89±0.26, 1.25±0.10, 1.07±0.14) also increased compared with control group(0.63±0.09,0.78±0.16,0.69±0.11; P<0.05 or <0.01). On day 45,75, 120 and 150 of the experiment, the expression of RyR2 mRNA in 74.7(0.49±0.06,0.51±0.07,0.57±0.11, 0.47±0.11), 248.7(0.47±0.03,0.52±0.09, 0.70±0.10, 0.78±0.09)mg/kg AlCl3 groups was highly increased compared with control group (0.24±0.07, 0.32±0.04, 0.30±0.06, 0.27±0.06; P<0.05 or<0.01). Conclusion Al increases [Ca2+]i by increasing the expression of the RyR2 mRNA and L-Ca2+α1C mRNA, thus exerts an irreversible neuronal toxicity.