The improvement of the electroosmotic pump properties and the effects of the bi-directional electrostacking system on the pre-concentration factor were investigated.A portable electrokinetic flow analysis system with electroosmotic driving and bi-directional electrostacking unit was introduced.The improved system with graphite furnace atomic absorption spectrometry was employed to separate,pre-concentrate and determine Cr(Ⅵ) and Cd(Ⅱ)in mineral water.The detection limit of Cr(Ⅵ)and Cd(Ⅱ)was 9 ng/L and 10 ng/L(3б of blank,n=11),respectively.Their recoveries of 200ng/L Cr(Ⅵ) and 100ng/L Cd(Ⅱ) added to samples were(105～107)±2% and (104～106)±2%(n=3).

OBJECTIVETo evaluate the possible vascular effects of an environment carcinogen benzo(a)pyrene (BaP).

METHODSThe cytotoxicit of BaP and rat liver S9 (0.25 mg/mL)-activated BaP were examined by MTT assay. Thoracic aortic rings were dissected from Sprague-Dawley rats. Contraction of aortic rings was induced by 60 mmol/L KCl or 10(-6) mol/L phenylephrine (PE) in an ex-vivo perfusion system after BaP (100 μmol/L) incubation for 6 h. [Ca(2+)](i) was measured using Fluo-4/AM. For in-vivo treatment, rats were injected with BaP for 4 weeks (10 mg/kg, weekly, i.p.).

RESULTSBaP (1-500 μm) did not significantly affect cell viability; S9-activated BaP stimulated cell proliferation. BaP did not affect the contractile function of endothelium-intact or -denuded aortic rings. BaP did not affect ATP-induced ([Ca(2+)](i)) increases in human umbilical vein endothelial cells. In BaP-treated rats, heart rate and the number of circulating inflammatory cells were not affected. Body weight decreased while blood pressure increased significantly. The maximum aortic contractile responses to PE and KCl and the maximum aortic relaxation response to acetylcholine were significantly decreased by 25.0%, 34.2%, and 10.4%, respectively.

CONCLUSIONThese results suggest, in accordance with its DNA-damaging properties, that metabolic activation is a prerequisite for BaP-induced cardiovascular toxicity.

Animals ; Aorta ; drug effects ; Benzo(a)pyrene ; pharmacology ; Calcium ; metabolism ; Endothelial Cells ; drug effects ; metabolism ; Humans ; Male ; Rats ; Vasoconstriction ; drug effects

Adolescent ; Adult ; Aged ; Female ; Hepatitis B, Chronic ; therapy ; Humans ; Male ; Middle Aged ; Plasma Exchange ; methods ; Severity of Illness Index ; Sorption Detoxification ; methods ; Treatment Outcome

Adenine ; analogs & derivatives ; therapeutic use ; Adult ; Female ; Hepatitis B e Antigens ; blood ; Hepatitis B virus ; physiology ; Hepatitis B, Chronic ; blood ; drug therapy ; virology ; Humans ; Male ; Organophosphonates ; therapeutic use ; Thymidine ; analogs & derivatives ; therapeutic use ; Treatment Outcome ; Viral Load