Objective To observe effects of the folic acid deficient diet on plasma homocysteine(Hcy) level and lesions of aorta in rats. Methods Twenty male Wistar rats were divided into two groups, folic acid deficent group (FD) and control group (Ctl).The rats were fed with folic acid deficient diet and normal diet for 3 months,respectively. The levels of serum folic acid and plasma Hcy as well as the activities of superoxide dismutase(SOD) and glutathione peroxidase (GPX) in erythrocytes were measured.The histological changes of aorta were also examined by light microscope. Results After 3 months treated with folic acid deficient diet, serum folic acid level 〔(6 08?1 84)?g/L〕 decreased significantly in rats of FD group compared either with pre experimental level 〔(13 32?2 02)?g/L〕 or with control one 〔(12 17?1 67)?g/L〕. Meanwhile, plasma homocycteine level increased significantly in rats of FD group 〔(28 66?6 07)?mol/L〕 compared either with pre experimental level 〔(9 75?1 86)?mol/L〕 or with control one 〔(9 49?1 77)?mol/L〕. The activity of erythrocytic SOD increased but GPX decreased obviously. The morphology lesions were also observed in aortic tissue. Conclusions Folic acid deficient diet induced hyperhomocysteinemia and arterial lesions.The high oxidant stress induced by hyper homocysteinemia may be one of mechanisms of arterial lesion.

A novel electrogenerated chemiluminescence (ECL) sensor for the determination of metoclopramide was developed by employing ruthenium complex as an ECL signal producer and an ordered mesoporous carbon (OMC) material as modified material. The ECL sensor was fabricated by adsorption ruthenium complex into a mixture of OMC and Nafion, which showed good electrochemical and ECL behaviors. It was found that the ECL intensity of the sensor fabricated was greatly enhanced in the presence of metoclopramide. Based on this finding, a highly sensitive and reproducible ECL method was developed for the determination of metoclopramide. The result showed that the ECL intensity was linear with the concentration of metoclopramide in the range from 1.0×10-10 to 5.0×10-7M and the detection limit was 3×10-11M. The ECL sensor exhibited a long-term stability and a fine reproducibility with relative standard deviation of 1.0 % for 1.0×10-10M metoclopramide in 18 continuous determinations. The developed method has been applied to the determination of metoclopramide in tablet samples with satisfactory results.

OBJECTIVETo apply pulse-field gel electrophoresis analysis(PFGE) in the analysis of cholera outbreak events and to determine the molecular epidemiological characteristics of Vibrio cholerae ( V. cholerae) isolates.

METHODSPFGE using restriction enzyme Not I was employed in the molecular subtyping of forty-one strains of V. cholerae isolated in cholera outbreak events from 2003 to 2005 in Guangzhou area and PFGE patterns were analyzed by BioNumerics Version 4.0 software to perform cluster analysis. Pattern profiles were compared by utilizing of Dice coefficient and UPGMA(unweighted pair group method with arithmetic averages). Comparison of PFGE typing results was performed with phage-biological typing and pathogenicity-associated genes typing.

RESULTSIn cholera outbreak events, PFGE could discriminate epidemiologically related and unrelated strains, having more discriminatory power than phage-biological typing and pathogenicity-associated genes-typing.

CONCLUSIONSMolecular sub-typing by PFGE could disclose the epidemiological relationships of strains from humans and the environment, providing molecular epidemiological evidence and support for the source-tracking of cholera outbreak events.

Bacterial Typing Techniques ; methods ; Cholera ; epidemiology ; microbiology ; Disease Outbreaks ; Electrophoresis, Gel, Pulsed-Field ; Humans ; Molecular Epidemiology ; Vibrio cholerae ; classification ; genetics ; isolation & purification

OBJECTIVETo apply multiplex polymerase chain reaction (MPCR) assay and sequencing in study of the carrying status of four pathogenicity-related genes of Vibrio cholerae (V.cholerae) and the variation of ctxA.

METHODSPrimers targeting cholera toxin sub-unit A gene (ctxA), toxin-coregulated pilus gene (tcpA), accessory cholera enterotoxin gene (ace), zonula occludens toxin gene (zot) were designed and the MPCR method was applied to detect the pathogenicity-related genes of 276 strains of V.cholerae isolates. The amplified fragments of ctxA gene were sequenced and the genetic homology of the amplified fragments of ctxA was analyzed.

RESULTSOf the 276 strains of V.cholerae, 93.9% strains from human sources belong to the pathogenicity-related genes type A (ctxA(+)tcpA(+)ace(+)zot(+) type) and 6.1% belong to pathogenicity-related genes type C (ctxA(-)tcpA(-)ace(-)zot(-) type). Type A strains from clinical sources were isolated from patients with mild to severe symptom and carriers, among which 68.5% were isolated from patients with mild symptom and 21.9% from carriers. All 63.6% of type C strains from clinical sources were isolated from patients with mild symptom and 36.4% from carriers. The proportion of type C strains that caused mild symptom was higher than that of type A strains. Of the 78 strains isolated from the environment, 9.0% strains belong to pathogenicity-related type A and 35.9% belong to the pathogenicity-related genes type B (ctxA(-)tcpA(-)ace(+)zot(+) type), while 55.1% belong to pathogenicity-related genes type C. The sequencing results showed little genetic variation among the amplified fragments for ctxA.

CONCLUSIONMPCR disclosed the polymorphic status of pathogenicity-related gene patterns in V.cholerae isolates of Guangzhou, providing effective means for further study on evolution of pathogenicity-related genes among V.cholerae isolates from human and environmental sources. This study also offers significant guidance for effective prevention, control and warning against cholera epidemic in local area.

China ; Cholera Toxin ; genetics ; DNA, Bacterial ; Genes, Bacterial ; genetics ; Genotype ; Humans ; Polymerase Chain Reaction ; Sequence Analysis ; Vibrio cholerae ; classification ; genetics ; isolation & purification