[Frequencies of 9 bp deletion of mitochondrial DNA in ethnic Miao, Buyi and Dong from Guizhou].

OBJECTIVE: To study the frequency of a 9 bp deletion polymorphism of mitochondrial DNA (mtDNA) in ethnic Miao, Buyi and Dong populations from Guizhou province. METHODS: Polymerase chain reaction-polyacrylamide gel electrophoresis (PCR-PAGE) was used to detect the 9 bp deletion. The result was verified with DNA sequencing. RESULTS: Two polymorphisms, including a standard pattern and a short pattern (the 9 bp deletion), were found among the three ethnic groups. The frequency of short pattern in 304 males was 23.0%. Respectively, those of Miao, Buyi and Dong ethnics were 28.6%, 26.8% and 13.7%. A statistically significant difference was detected among the three groups (P<0.05). CONCLUSION: The frequencies of the 9 bp polymorphism were relatively high among ethnic Miao, Buyi and Dong populations from Guizhou, and there was a significant difference between the three.

[A study of interleukin-10 gene polymorphisms in Miao, Dong and Buyi ethnics of Guizhou].

OBJECTIVE: To investigate allelic frequencies of interluekin-10 (IL-10) gene promoter in Miao, Dong and Buyi ethnics of Guizhou. METHODS: TaqMan MGB-based real-time PCR was used to determine the genotypes of IL-10 -819 and IL-10 -592 in 589 Miao, Dong and Buyi ethnics of Guizhou. RESULTS: The allelic frequency of IL-10 -819 in Miao ethnics was significantly different from those in Dong or Buyi ethnics. Allelic frequencies of IL-10 -592 in Miao ethnics was significantly different from those in Dong or Buyi ethnics. In Miao, Dong and Buyi ethnics, the distributions of genotype frequencies of IL-10 -819 and IL-10 -592 were statistically different from Han ethnics from Guizhou and Taiwan of China as well as South Koreans. CONCLUSION: There is a heterogeneity in the frequencies of polymorphisms of IL-10 promoter among different ethnic groups.

[Polymorphisms of homocysteine metabolism enzyme-related genes MS and MSR in Buyi, Dong and Miao ethnics from Guizhou].

OBJECTIVE: To investigate polymorphisms of homocysteine metabolism enzyme-related genes methionine synthase (MS) and methionine synthase reductase (MSR) in Buyi, Dong, Miao ethnics from Guizhou. METHODS: Genotypes of MS and MSR genes of healthy individuals from the three ethnic groups were determined with a TaqMan-MGB probe genotyping method and compared. RESULTS: For Buyi, Dong and Miao ethnics from Guizhou, frequencies of MS gene 2756G allele were respectively 12.0%, 8.9% and 15.4%. However, no significant difference was found by statistics. Frequencies of MS A2756G alleles for the three ethnic groups are similar to those of Han Chinese from Beijing and Henan, Hui ethnics from Ningxia as well as European populations, but differ significantly from those of Japanese, Indians, Africans and Nigerians (P < 0.05). Frequencies of MSR gene 66 G allele were respectively 32.3%, 30.4% and 21.2% for Buyi, Dong and Miao ethnics. Miao is significantly lower than Buyi and Dong (P< 0.05). Frequencies of MSR gene A66G alleles for the three ethnic groups are similar to those of Han Chinese from Beijing and Guangdong, Japanese, Africans and Nigerians populations, but differ significantly from those of Indians and European (P< 0.05). CONCLUSION: The distributions of MS gene A2756G and MSR gene A66G polymorphisms have differed significantly between the three ethnic groups and individuals from various regions.

[Influence of APP(SWE) transfection on nicotinic receptors in cultured neuronal cells].

OBJECTIVE: To investigate the influence of APP(SWE) on the expression of neuronal acetylcholine receptors (nAChRs) and its relationship with Alzheimer's disease (AD). METHODS: APP(SWE), carried the Swedish family AD double mutants, were transfected into SH-SY5Y cells and primary cultured neurons from rat brains to build a cellular model of AD. The mRNA levels of APP and nAChRs, and the protein levels of total APP, αAPPs and nAChRs in the cultured cells were measured using real-time PCR and Western blot, respectively. The numbers of α3 nAChR were determined by receptor-[³H]epibatidine binding assay. RESULTS: Increased expressions of Swedish 670/671 APP at mRNA and protein levels, and down-regulation of αAPPs were observed in both of the cultured neuronal cells transfected with APP(SWE). A significant increase of α7 nAChR expression at protein and mRNA levels was detected in the APP(SWE) transfected SH-SY5Y cells. On the other hand, after transfection with APP(SWE), the expressions of α3 nAChR at protein and mRNA levels in SH-SY5Y cells, and α4 nAChR at mRNA level in primary cultured neurons were inhibited. In addition, the numbers of receptor binding sites were deceased in SH-SY5Y cells overexpressing with APP(SWE). CONCLUSION: Overexpression of APP(SWE) can decrease αAPPs and modify nAChRs by increasing expression of α7 nAChR and decreasing α3 and α4 nAChRs, which might play an important role in the pathogenesis of AD.

Inhibiting gene expression of alpha3 nicotinic receptor in SH-SY5Y cells with the effects on APP metabolism and antioxidation in Alzheimer's disease.

In order to examine the effects of alpha3 nicotinic acetylcholine receptor (nAChR) in connection with the pathogenesis of Alzheimer's disease (AD), neuroblastoma (SH-SY5Y) cells were transfected with small interference RNAs (siRNAs) that target specifically towards alpha3 nAChR. The expressions of alpha3 nAChR mRNA and protein were measured by real-time PCR and Western blotting, respectively. The levels of the alpha-form of secreted amyloid precursor protein (alphaAPPs) and total-APP were determined by Western blotting. SH-SY5Y cells transfected with siRNA were then treated with 1muM beta-amyloid peptide (Abeta)(1-42), following which the levels of lipid peroxidation, the activities of superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), and the reduction rate of MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] were characterized by utilizing spectrophotometric procedures. As compared to controls, SH-SY5Y cells transfected with siRNA expressed the decreases in the levels of alpha3 nAChR mRNA and protein by 98% and 66% lower levels, respectively; exhibited reduced level of the alphaAPPs; and demonstrated enhanced lipid peroxidation, decreased rate of MTT reduction, and declined activities of SOD and GSH-Px. Inhibited gene expression of the alpha3 nAChR enhanced the toxicity exerted by Abeta. These results indicate that alpha3 nAChR may improve cleavage of APP by alpha-secretase, enhance antioxidation and inhibit the toxicity of Abeta, suggesting that the receptor might play an important role in AD.

[Influence of inhibited gene expression of alpha 3 nicotinic acetylcholine receptor by RNA interference on anti-oxidation in SH-SY5Y cells].

OBJECTIVES: To investigate the neuroprotective function of alpha 3 nicotinic acetylcholine receptor (nAChR) by inhibiting the gene expression in human neuroblastoma (SH-SY5Y) cells using small interference RNA (siRNA). METHODS: The siRNA coding oligonucleotide sequences targeting alpha 3 nAChR were designed and synthesized. The annealed product was cloned into pSilencer 3.1-H1 neo vector. The recombinant alpha 3 nAChR pSilencer 3.1-H1 neo vector was transfected into the SH-SY5Y cells. The stable clones were screened by G418 medium, and the levels of alpha 3 nAChR mRNA and protein were monitored by using real-time PCR and Western blotting, respectively. After the SH-SY5Y cells with siRNA treatment were exposed to 1 micromol/L Abeta(1-42), MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide], SOD, GSH-px and the lipid peroxidation were measured by spectrophotometry. RESULTS: Compared with the controls, the expression levels of mRNA and protein in the stable SH-SY5Y clone cells transfected with the recombinant alpha 3 nAChR pSilencer 3.1-H1 neo vector were decreased with inhibitory efficiency of 98% and 66%, respectively, the MTT reduction decreased; the product of lipid peroxidation was increased and the activities of SOD and GSH-px were decreased. Biologically, the gene expression inhibition of alpha 3 nAChR enhanced the toxicity induced by Abeta in SH-SY5Y cells. CONCLUSIONS: The expression inhibition of alpha 3 nAChR as a result of recombinant alpha 3 nAChR siRNA can induce oxidative stress and improve the toxicity of Abeta on SH-SY5Y cells, indicating that alpha 3 nAChR may play a significant neuroprotective role in the pathogenesis of Alzheimer disease.

Correlations between polymorphisms in the uridine diphosphate-glucuronosyltransferase 1A and C-C motif chemokine receptor 5 genes and infection with the hepatitis B virus in three ethnic groups in China.

Objective To determine whether genetic polymorphisms in the uridine diphosphate-glucuronosyltransferase 1A ( UGT1A) and the C-C motif chemokine receptor 5 ( CCR5) genes are associated with hepatitis B virus (HBV) infection in Yi, Yao and Han ethnic groups in the Guizhou Province of China. Methods The study enrolled subjects with and without HBV infection. Whole blood was used for DNA genotyping using standard techniques. The study determined the frequencies of several polymorphic alleles ( UGT1A6 [rs2070959], UGT1A1 [rs8175347], CCR5-59029 [rs1799987] and CCR5Δ32 [rs333]) and then characterized their relationship with HBV infection. Results A total of 404 subjects were enrolled in the study: 138 from the Yao group, 101 from the Yi group and 165 from the Han group. There was a significant difference in the frequency of UGT1A1 rs8175347 polymorphisms among the three groups. The rates of 7TA carriers of UGT1A1 rs8175347 in all three groups were significantly higher than the other genotypes. Individuals with genotype AA of UGT1A6 rs2070959 in the Yi group had a higher risk for HBV infection than in the Yao and Han groups. The frequency of genotype GG in CCR5-59029 in the Yao group was significantly higher than in the Yi group. The genotypes of CCR5Δ32 were not associated with HBV infection. Conclusion These findings provide genetic and epidemiological evidence for an association of UGT1A and CCR5-59029 polymorphisms with HBV infection in Chinese Yi and Yao populations.

Blood metallothionein transcript as a biomarker for metal sensitivity: low blood metallothionein transcripts in arsenicosis patients from Guizhou, China.

BACKGROUND: Because metallothionein (MT) is a metal-binding protein that protects against metal intoxication, it could be a biomarker for individual sensitivity to metal toxicity. OBJECTIVE: We assessed the use of bloodborne MT transcript as a reflection of tissue MT levels and examined the potential role of MT in arsenic toxicity in an environmentally exposed human population. METHOD: Rodents were treated with zinc or nonmetallic MT inducers for 4 days, and the blood and tissues were collected for MT transcript analysis by real-time reverse transcriptase-polymerase chain reaction and MT protein determination by the cadmium-hemoglobin assay. Blood and buccal cell samples were collected from arsenicosis patients and healthy subjects residing in Guizhou, China, and total RNA was isolated for MT transcript analysis. RESULTS: There was a positive correlation between blood MT-1 and MT-2 transcripts and corresponding hepatic or renal MT transcript levels in rats and mice. Furthermore, there was a positive correlation between blood MT-1 and MT-2 transcript and tissue MT protein levels in these animals. A positive correlation also occurred between human blood MT and buccal cell MT transcript levels. MT-1A and MT-2A were the major isoform transcripts in human blood and buccal cells, and significantly lower MT levels were seen in arsenicosis patients compared with healthy subjects. CONCLUSIONS: Blood MT transcript appears to be a useful biomarker of tissue MT levels. Arsenicosis patients in Guizhou show significantly lower MT transcript levels in blood, which may have predisposed this population to arsenic intoxication.

[Frequencies of GSTM1, GSTT1, and GSTP1 polymorphisms in ethnic minority from Guizhou].

OBJECTIVE: To investigate the frequencies of GSTM1, GSTT1 and GSTP1 polymorphisms in Dong, Yi and Yao ethnic groups from Guizhou. METHODS: In 321 volunteers who were population-based, GSTM1 and GSTT1 polymorphisms were analyzed by a multiplex-PCR procedure, whereas GSTP1 polymorphism was analyzed by PCR-RFLP method. RESULTS: Null genotype for GSTM1 and GSTT1 was 59.6%-71.2% and 39.4%-72.5%, respectively. The genotypic distribution of GSTP1 was 63.3%-75% for AA, 23.2%-35.8% for AG, 0-1.9% for GG, whereas the allelic frequencies were 81.2%-86.6% for the A allele, and 13.4%-18.8% for the G allele. CONCLUSION: There is a significant relationship between GSTT1 frequencies and ethnic populations.

[Research into methylation of p16 gene in the patients suffering from coal-burnt arsenism in Xingren County Guizhou Province].

OBJECTIVE: To probe into the situation and significance of p16 gene CPG island methylation in patients with arseniasis caused by coal-burning pollution. METHODS: DNA was extracted using the Phenol-Chloroform method from leukocytes of 51 patients suffered from coal-burnt arsenism and 52 healthy volunteers. The quantity of the DNA was determined by UV spectrophotometry. Target DNA was denatured by NaOH, then the single strand DNA was modified by sodium bisulfite, converting all unmethylated (but not the methylated) cytosines to uracil. Subsequently a nested amplification with primers specific for methylated versus unmethylated DNA was performed, and PCR products were detected by gel electrophoresis. RESULTS: Hypermethylation of the p16 CPG island was presented in 94.1% of the patients suffering from coal-burnt arsenism and in 73.1% of the healthy volunteers. There was statistical difference (P < 0.05) between them. CONCLUSIONS: Methylation of p16 gene CPG island should have important pertinence in the metabolism of coal-burnt arsenism.

[Protection of Tianshen Yizhi Recipe against low expression of nicotinic receptor and neurotoxicity induced by beta-amyloid peptide].

OBJECTIVE: To investigate the inhibition effects of Tianshen Yizhi Recipe (TSYZR), a compound traditional Chinese herbal medicine, on decreased expression of nicotinic acetylcholine receptor (nAChR) and the neurotoxicity as well as lipid peroxidation induced by beta-amyloid peptide (Abeta) in human SH-SY5Y neuroblastoma cells. METHODS: The SH-SY5Y cells were treated by a certain concentration of TSYZR, and then exposed to Abeta(25-35). Methyl thiazolyl tetrazolium reduction assay was carried out to understand the influences of the drugs on cellular viability. Expressions of nAChR subunits (alpha3 and alpha7) at protein and mRNA levels were detected by Western-blotting and reverse transcription polymerase chain reaction, respectively. Lipid peroxidation was measured by thiobarbituric acid to observe the capacity of antioxidant of the drugs. RESULTS: TSYZR at a safe concentration could increase alpha7 protein in the cells, inhibit decreased expressions of alpha3 and alpha7 nAChR subunit proteins, prevent lower expression of alpha7 mRNA in SH-SY5Y cells induced by Abeta, reduce the neurotoxicity and lipid peroxidation resulting from Abeta, but had no significant effect on the lower expression of alpha3 mRNA. CONCLUSIONS: TSYZR can up-regulate the expression of alpha7 nAChR subunit protein and prevent decreased expressions of nAChRs and neurotoxicity as well as lipid peroxidation induced by Abeta. This drug may play an important therapeutic role in treatment of Alzheimer disease.

[Polymorphism analysis of seven Y-STR loci in Shui population in Guizhou, China].

The objective of this study was to investigate the polymorphism of seven Y-specific STR loci in Shui ethnic population of Guizhou, China, and to obtain the polymorphism information in this minority. One trinucleotide STR locus and six tetranucleotide STR loci were simultaneously amplified with fluorescently labeled primers, and genotypes were determined with ABI PRISM 377 DNA Sequencer. Allele frequencies, genetic diversity and haplotype diversity were calculated. Among 94 unrelated males, 6, 4, 6, 2, 3, 5, 4 alleles were observed in loci DYS19, DYS389 I, DYS389 II, DYS390, DYS391, DYS392 and DYS393, respectively. Altogether, 27 haplotypes were identified for the seven Y-STR loci. The genetic diversity values for each locus ranged from 0.124 (DYS389 I) to 0.630 (DYS19). The haplotype diversity value was 0.868. High haplotype diversities were found in Shui population of Guizhou. The study suggests that these seven Y-STR loci are valuable Y-specific markers for establishing a Y-STR database, understanding ethical origin and migrations and for personal identification.

[Y-SNP analysis of Bouyei, Gelao, Mulao, Maonan, and Zhuang populations in Guizhou].

To understand the patrilineal genetic structure of Baiyue ethnic group in Guizhou province, we studied the frequencies of Y-chromosome haplotypes which consisted of 10 single nucleotide polymorphisms (SNPs) by using the PCR-RFLP method. Five haplotypes were found in Baiyue ethnic group in Guizhou, among which H8 was the most common, whereas that of Miao in Guizhou tended to be H8, H11 and H12 haplotypes. Compared with Miao in Guizhou, the Guizhou Baiyue (excluding Sui and Dong) was significantly different and could be regarded as an independent ethnic group. Differences were also found in the same ethnic group among different areas.

[Analysis of polymorphisms in Y-DNA haplotypes and mtDNA haplogroups in Yao ethnic group from Guizho].

The frequencies of Y-chromosome haplotypes consisting of 12 single nucleotide polymorphisms (SNP) and mitochondrial DNA (mtDNA) haplotypes consisting of 9 SNPs were investigated using PCR-RFLP in 97 Yaos from Guizhou to study the patrilineal and matrilineal genetic structure and the origin of Yao Ethnic Group from Guizhou. Results showed that all 97 samples were classified into 4 Y-DNA haplotypes (H7, H8, H9 and H11). The major haplotype H7 of Hmong-Mien Population was highly prevalent (92.4%) in Yaos from Guizhou. Eight mtDNA haplotypes were identified through mtDNA analysis and all the haplotypes could be classified into 5 haplogroups (B4, B5, D4, D5 and N*) that were defined previously. The frequency of a 9-bp deletion in the human mtDNA Co II/tRNALys intergenic region was 58.2% in the 97 samples. These data suggest that the patrilineal genetic structure of Yao ethnic group from Guizhou was simple and Yaos from Guizhou had the typical genetic character of the Hmong-Mien Population and some admixture with other populations. The matrilineal genetic structure of Yaos from Guizhou was relatively complex and the 9-bp deletion was a characteristic genetic marker of the matrilineal genetic structure of Yaos from Guizhou.

[Effect of beta-amyloid peptides on alpha-7 nicotinic receptor status in astrocytes and neurons, and its relationship to pathogenesis of Alzheimer's disease].

OBJECTIVE: To study the alterations of alpha-7 nicotinic receptor (nAChR) status in human brain tissues with Alzheimer's disease (AD) and mouse brain tissues with Swedish APP670/671 gene mutation, and to study the effect of beta-amyloid peptides (A-beta) on alpha-7 nAChR status in cultured astrocytes and neurons. METHODS: Postmortem brain tissues from patients with AD and mouse brain tissues with Swedish APP mutation were collected. The expression of alpha-7 nAChR on astrocytes and neurons was detected by immunohistochemistry (ABC method). The alpha-7 nAChR protein level was measured by Western blotting. On the other hand, cultured astrocytes and neurons were treated with different concentrations of A-beta 25 - 35. The alpha-7 nAChR protein level was then measured. RESULTS: Increased number of astrocytes surrounding senile plaques was observed in AD brain tissues. In AD brain tissues, as compared to age-matched controls, alpha-7 nAChR protein level was increased in astrocytes, but decreased in neurons. High level of alpha-7 nAChR protein was also observed in mouse brain tissues with APP mutation. Exposure to A-beta 25 - 35 induced an increase (up to 38%) in alpha-7 nAChR protein level in astrocytes but a decrease (up to 32%) in neurons. CONCLUSIONS: Decrease in alpha-7 nAChR level in neurons may be related to the pathogenesis of AD, whereas an increased level of alpha-7 nAChR in astrocytes, as induced by excessive A-beta, may represent a compensatory neuroprotective response.

[Influence of beta-amyloid peptide on cell membrane lipids and cholinergic receptors in human neuroblastoma SH-SY5Y cells].

OBJECTIVE: To study the effects of beta-amyloid peptide (Abeta) on cell membrane lipids and cholinergic receptors of human neuroblastoma cells. METHODS: Human SH-SY5Y neuroblastoma cells were treated with different concentrations of Abeta(1-42) with and without pretreatment of vitamin E. MTT [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] reduction, lipid peroxidation, protein oxidation and phospholipids were measured by spectrophotometry. Levels of cholesterol and unbiquinone were determined by high-performance liquid chromatography (HPLC). The numbers of cholinergic receptor binding sites were determined by receptor binding assay and the protein levels of nicotinic receptor alpha3 and alpha7 subunits were studied by Western blotting. RESULTS: SH-SY5Y cells showed decreased reduction rates of MMT and phospholipids, and increased lipid peroxidation and protein oxidation after exposure to Abeta (0.1 micromol/L) as compared to the control. The number of cholinergic receptor binding sites, the protein level of nicotinic receptor alpha3 and alpha7 subunits and the content of ubiquinone decreased in cells treated with high dose of Abeta (1 micromol/L). Although the level of cholesterol was not changed in any way, vitamin E partially prevented the neurotoxic effects of Abeta. CONCLUSION: beta-amyloid peptide reduces the level of cell membrane lipids and cholinergic receptors in human SH-SY5Y neuroblastoma cells, likely through the induction of an enhanced oxidative stress.

Characterization of polymorphisms in the mitochondrial DNA of twelve ethnic groups in the Guizhou province of China.

To characterize the genetic profiles and relationships between ancient ethnic populations, we analyzed polymorphisms in mitochondrial DNA (mtDNA) isolated from the blood of 753 members of 12 ethnic groups (Buyi, Dong, Gelao, Hui, Man, Miao, Menggu, Mulao, Maonan, Qiang, She and Zhuang) living in the Guizhou Province of China. The 9-bp deletion of mtDNA was detected by the polymerase chain reaction (PCR) and PCR-PAGE, and 11 SNPs by restriction fragment length polymorphism and mini-sequencing. Thereafter, these genotyping results were verified by PCR-DNA sequencing. The mtDNA of these populations exhibited considerable diversity, both with respect to the haplogroups M and N, and subgroups thereof. The differences between the major ethnic groups reflected the maternal inheritance. These ethnic groups in Guizhou demonstrated a genetic profile that differed considerably from that of other Asian populations. Our findings indicate that the matrilineal genetic profiles of Guizhou groups are relatively complex and distinct, showing relationships that reflect national history and geography.

Oxidative stress induced by beta-amyloid peptide(1-42) is involved in the altered composition of cellular membrane lipids and the decreased expression of nicotinic receptors in human SH-SY5Y neuroblastoma cells.

The neurotoxic effects and influence of beta-amyloid peptide (Abeta)(1-42) on membrane lipids and nicotinic acetylcholine receptors (nAChRs) in human SH-SY5Y neuroblastoma cells were investigated in parallel. Exposure of the cultured cells to varying concentrations of Abeta(1-42) evoked a significantly decrease in cellular reduction of MTT (3-(4,5-dimethylthiazol-2-yl)-2,5,diphenyl tetrazolium bromide), together with enhanced lipid peroxidation and protein oxidation. Significant reductions in the total contents of phospholipid and ubiquinone-10, as well as in the levels of the alpha3 and alpha7 subunit proteins of nAChRs were detected in cells exposed to Abeta(1-42). In contrast, such treatment had no effect on the total cellular content of cholesterol. Among these alterations, increased lipid peroxidation and decreased levels of cellular phospholipids were most sensitive to Abeta(1-42), occurring at lower concentrations. In addition, when SH-SY5Y cells were pretreated with the antioxidant Vitamin E, prior to the addition of Abeta(1-42), these alterations in neurotoxicity, oxidative stress, composition of membrane lipids and expression of nAChRs were partially prevented. These findings suggest that stimulation of lipid peroxidation by Abeta may be involved in eliciting the alterations in membrane lipid composition and the reduced expression of nAChRs associated with the pathogenesis of AD.

[Fluorosis on expression of nicotinic acetylcholine receptors in protein and gene levels in human SH-SY5Y neuroblastoma cells].

OBJECTIVE: To investigate the influence of fluorosis on nicotinic acetylcholine receptors (nAChRs) in protein and gene levels in SH-SY5Y cells and the mechanism of the receptor modification. METHODS: SH-SY5Y cells, a human neuroblastoma cell line, were incubated with different concentrations of fluoride or with antioxidant for 48 hours. The functions of cells were measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) method, and protein oxidation detected by carbonyl content; the alpha3 and alpha7 nAChR subunits in protein level were measured by Western blotting and in mRNA level by RT-polymerase chain reaction (RT-PCR). RESULTS: In high-dose group as compared to the control, the decreased MTT (49%), increased protein oxidation (72%), and lower expression of alpha3 (51%) and alpha7 (47%) nAChR subunit proteins were obviously observed in SH-SY5Y cells. There were no changes in expression of nAChR subunit mRNAs between the cells treated with fluoride and those un-treated in controls. Prior treatment with antioxidant resulted in preventing the decrease of nAChR protein in cells exposed to the high doses of fluoride. CONCLUSION: Fluorosis should result in damage of cells and the declined expression of nAChRs in protein levels, but no influences on gene expression of the receptors in human neuroblastoma neurons. The decreased nAChR proteins might be involved in the mechanism of oxidative stress induced by fluorosis.

[The sequence polymorphism of Y-chromosome DNA and mtDNA of Dong Ethnic of Congjiang, Guizhou].

To study the patrilineal and matrilineal genetic structure and the origin of Dong Ethnic of Congjiang Guizhou. Study the distribution of Y-chromosome haplotypes which consisted of 10 SNPs of Y-DNA and mtDNA haplogroups consisted of 11 SNPs by using PCR-RFLP method. The result is three haplotypes H6,H11,H14 were detected, the frequency of H11 is 92.5%. Six haplogroups were identified by mtDNA analysis, 75% of the people can be identified. The patrilineal genetic structure of Dong of Guizhou is simple, Principle component indicated that the structure is closer to Zhuang-Dong branch of Sino-Tibetan language family. The matrilineal genetic structure of Dong of Guizhou is complicated.