Search PubMed⌕ Search

Biomedical subjects

X Miao

Publications and source records attributed to X Miao.

At least 19 recordsLinked to original sources
PubMed2006

A novel T-77C polymorphism in DNA repair gene XRCC1 contributes to diminished promoter activity and increased risk of non-small cell lung cancer.

X-ray repair cross-complementing 1 (XRCC1) plays a key role in DNA base excision repair and cells lacking its activity are hypersensitive to DNA damage. Recently, we reported a SNP (rs3213245, -77T>C) in the XRCC1 gene 5' untranslated region (UTR) was significantly associated with the risk of developing esophageal squamous-cell carcinoma. Computer analysis predicted that this SNP was in the core of Sp1-binding motif, which suggested its functional significance. Gel shift and super shift assays confirmed that -77T>C polymorphic site in the XRCC1 promoter was within the Sp1-binding motif and the T>C substitution greatly enhanced the binding affinity of Sp1 to this region. Luciferase assays indicated that the Sp1-high-affinity C-allelic XRCC1 promoter was associated with a reduced transcriptional activity. The association between -77T>C and three other amino-acid substitution-causing polymorphisms in XRCC1 and risk of lung cancer was examined in 1024 patients and 1118 controls and the results showed that only the -77T>C polymorphism was significantly associated with an increased risk of developing lung cancer. Multivariate logistic regression analysis found that an increased risk of lung cancer was associated with the variant XRCC1 -77 genotypes (TC and CC) compared with the TT genotype (OR=1.46, 95% CI=1.18-1.82; P=0.001) and the increased risk was more pronounced in smokers (OR=1.63, 95% CI=1.20-2.21) than in non-smokers (OR=1.28, 95% CI=0.94-1.76). Taken together, these results showed that the functional SNP -77T>C in XRCC1 5'UTR was associated with cancer development owing to the decreased transcriptional activity of C-allele-containing promoter with higher affinity to Sp1 binding.

Adult↗
PubMed2005

A common polymorphism in the 3'UTR of cyclooxygenase 2/prostaglandin synthase 2 gene and risk of lung cancer in a Chinese population.

Cyclooxygenases (COXs) are key enzymes that convert arachidonic acid to prostaglandins. Overexpression of COX-2, one of the COX isozymes, has been shown to be an early event in lung carcinogenesis and may play an important role in lung cancer development. A common single nucleotide polymorphism, T8473C, located within a potential functional region in the 3'UTR of COX-2 gene was identified and we hypothesized that this COX-2 variant is associated with lung cancer risk. To test this hypothesis, we genotyped this variant in a case-control study of 322 histologically-confirmed lung cancer patients and 323 age and sex frequency-matched cancer-free controls in a Chinese population. The results showed that the frequencies of variant genotypes 8473CT/CC were significantly less common in the cases (27.3%) than in the controls (35.3%) (P=0.034), suggesting that the 8473C allele was protective against lung cancer. Multivariate logistic regression analyses revealed that the COX-2 variant genotypes (8473CT/CC) were associated with a significantly decreased risk of lung cancer compared with the 8473TT wild-type homozygotes (OR=0.64, 95% CI=0.45-0.92). When we defined the reference group as non-smokers having the 8473CT/CC variant genotypes, the smokers with the 8473TT wild-type genotype had the greatest risk (adjusted OR=5.28, 95% CI=3.10-9.00). These findings indicate that the COX-2 T8473C polymorphism may contribute to lung cancer susceptibility in the Chinese population. Further larger molecular epidemiological studies are warranted to confirm these findings.

3' Untranslated Regions↗
PubMed2005

Radiation-induced changes in gene expression in the silkworm revealed by serial analysis of gene expression (SAGE).

Serial analysis of gene expression (SAGE) was used to examine the profile of expressed genes during embryonic development in the domesticated silkworm, Bombyx mori, after irradiation with Cobalt-60. A comparison of the SAGE sequence tags derived from irradiated embryos with those from normal embryos revealed 673 differentially expressed genes (P < 0.01 and at least three folds change). Of these, 292 genes were highly expressed in normal embryos and 381 genes were highly expressed in irradiated embryos. These results provide valuable information for understanding the mechanisms of radiation-induced changes in gene expression. In addition, it was noted that the generation of longer cDNA fragments from SAGE tags is an efficient way to identify genes, thereby facilitating the analysis of large numbers of unknown genes.

Animals↗
PubMed2005

Functional polymorphisms in cell death pathway genes FAS and FASL contribute to risk of lung cancer.

BACKGROUND: The FAS and FASL system plays a key role in regulating apoptotic cell death and corruption of this signalling pathway has been shown to participate in immune escape and tumorigenesis. There is reduced expression of FAS but elevated expression of FASL in many types of human cancers including lung cancer. We recently reported an association between functional polymorphisms in FAS (-1377G-->A) and FASL (-844T-->C) and risk of oesophageal cancer. OBJECTIVE: To examine the contribution of these polymorphisms to risk of developing lung cancer. METHODS: Genotypes of 1000 lung cancer patients and 1270 controls were analysed by PCR based restriction fragment length polymorphism. Associations with risk of lung cancer were estimated by logistic regression. RESULTS: Compared with non-carriers, there was a 1.6 fold excess risk of developing lung cancer for carriers of the FAS -1377AA genotype (odds ratio (OR) 1.59, 95% confidence interval (CI) 1.21 to 2.10; p = 0.001), and 1.8 fold excess risk (OR 1.79, 95% CI 1.26 to 2.52; p = 0.001) for carriers of FASL -844CC. Gene-gene interaction of FAS and FASL polymorphisms increased risk of lung cancer in a multiplicative manner (OR for the carriers of both FAS -1377AA and FASL -844CC genotypes 4.18, 95% CI 2.83 to 6.18). Gene-environment interaction of FAS or FASL polymorphism and smoking associated with increased risk of lung cancer was also found. CONCLUSION: These results are consistent with our initial findings in oesophageal cancer and further support the hypothesis that the FAS and FASL triggered apoptosis pathway plays an important role in human carcinogenesis.

Aged↗
PubMed2004

Bichromatic slowing and collimation to make an intense helium beam.

The bichromatic force has been used to both slow and collimate a beam of metastable 2(3)S He atoms (He*). The collimation capture range is an extraordinary +/-85 m/s corresponding to approximately 0.18 radians from our source. Both slowing and collimation were accomplished in the unprecedented short distance of approximately 5 cm each. The overall brightness increase is x3200, and there is potential for considerably more.

Journal Article↗
PubMed2001

Chinese students' concept of mental health.

This study explored Chinese students' concept of mental health through a questionnaire completed by 999 students from six primary schools, six high schools, and three universities in Shanghai. The results confirmed the expectation that Chinese students' mental health concept would be multifaceted and would reflect psychological, physical, and sociocultural factors. An exploratory factor analysis on 12 mental health items with a subsample extracted a three-factor model, which was cross-validated by confirmatory factor analysis with a different subsample. These three factors were labeled as Affective Strength, Adaptive Strength, and Personal Strength. No gender differences were found. The grade differences supported the notion that Chinese students' concept of mental health seems to be more consistent with the developmental paradigm of health. The senior years in primary school could be the turning point at which children start to conceptualize health as a holistic experience by recognizing the importance of mental health.

Adaptation, Psychological↗
PubMed2001

[Cloning and phylogenetic analysis of hepatitis-associated TT virus subgenome].

Polymerase chain reaction (PCR) was utilized for the DNA amplification from transfusion transmitted virus (TTV) positive serum samples. Five TTV DNA fragments, overlapped about 90% of the genome, were amplified by long template PCR for the generation of TTV subgenome. Recombinant plasmids were obtained by directly inserting PCR products into pT-Adv vector, and DNA sequence analyses showed they were TTV DNA fragments. By using specific restriction enzymes, five TTV DNA fragments were ligated into a TTV DNA subgenome clone and named as TTV021. TTV021 has been deposited in GenBank database with the accession number AF254410. The results of computer analyses showed that TTV021, 3472 nt long, contains two open reading frames (ORF1, 785 aa; ORF2, 146 aa). Identity alignments between TTV021 and other TTV isolates indicated several high conserved regions existed. Phylogenetic analysis of 356 nt from TTV021 suggested that the isolate has close evolutionary relationship with CHN1 (type 1a), but has far relation with other TTV isolates.

Circoviridae↗
PubMed2000

[Effect of yinchen dandao decoction on plasma fibronectin, biliary thromboxane A2 and prostaglandin I2 in human and animal suffering from acute cholangitis].

OBJECTIVE: To study the therapeutic mechanism of Yinchen Dandao decoction (YCDDD) in treating acute cholangitis. METHODS: Twenty-four patients with acute cholangitis and 36 cholangiolithiasis patients were randomly classified into the treated group and the control group, and all of these patients had undergone surgical operation. The treated group were given orally YCDDD 3 days after operation for 1 week, and plasma fibronectin (FN), biliary thromboxane A2(TXA2) and prostaglandin I2(PGI2) were measured and compared before and after oral administration of the drug. The models of cholangitis were established in rabbits, which were also randomly grouped into the treated group and the control group, and the same parameters (FN, TXA2, PGI2) were observed as in rabbits. RESULTS: The level of FN was significantly lower in cholangitis patients than that in the cholangiolithiasis patients before operation (P < 0.01), and compared to the control group, it obviously raised after YCDDD treatment (P < 0.01), the same happened in the cholangiolithiasis patients. The value of TXA2 and PGI2 in the bile was obviously higher (P < 0.01, P < 0.05) in cholangitis patients than those in chlangiolithiasis, and obviously reduced after YCDDD administration (P < 0.01). The level of FN in the treated group and the level of biliary TXA2 and PGI2 in rabbits with cholangitis were significantly higher than those in the control group (P < 0.01). CONCLUSION: YCDDD caused the increase of FN and decrease of biliary TXA2 and PGI2, which might be one of the mechanisms of the drug carried out in cholangitis patients.

6-Ketoprostaglandin F1 alpha↗
PubMed1999

Reconstitution of a minimal RNA degradosome demonstrates functional coordination between a 3' exonuclease and a DEAD-box RNA helicase.

The RNA degradosome is a multiprotein complex required for the degradation of highly structured RNAs. We have developed a method for reconstituting a minimal degradosome from purified proteins. Our results demonstrate that a degradosome-like complex containing RNase E, PNPase, and RhlB can form spontaneously in vitro in the absence of all other cellular components. Moreover, ATP-dependent degradation of the malEF REP RNA by the reconstituted, minimal degradosome is indistinguishable from that of degradosomes isolated from whole cells. The Rne protein serves as an essential scaffold in the reconstitution process; however, RNase E activity is not required. Rather, Rne coordinates the activation of RhlB dependent on a 3' single-stranded extension on RNA substrates. A model for degradosome-mediated degradation of structured RNA is presented with its implications for mRNA decay in Escherichia coli.

ATP-Binding Cassette Transporters↗
PubMed1999

Effect of dental material HEMA monomer on human dental pulp cells.

The purpose of this study was the cytotoxicity assay of dental material HEMA monomer to human dental pulp cell by MTT method and application of the flow cytometry to analyze effect of dental material on the cell cycle progression. The result of MTT method showed the inhibition of cell growth and 50% inhibitory concentration (IC50) of HEMA monomer in human dental pulp cell was 815.19 micrograms/ml. The result of the flow cytometry showed that there was a perturbation on human dental pulp cell cycle progression at the phases of Sand G2M with a dose-dependent manner. Biomaterials including dental materials should be safety to human bodies. Presently, many methods for testing the cytotoxicity of biomaterials were suggested. [1-2] MTT method is one of the cytotoxicity assay. It was provided by Monsmnn. [3] MTT is a kind of tetrazolium salt [3-(4,5-dimethylthiazol-2yi)-2,5-diphenyl tetrazolium bromide]. MTT method is the rapid, precision and quantitative colorimetric assay for cytotoxicity. It can be used to measure the proliferation, cytotoxicity or activation of living cells and is capable of handling large number of samples. Many investigators have used this advanced method.[4] Flow cytometry (FCM) analyzes the quantity of DNA bonded with dyes in each cell. It can provided the information of the cell cycle progression in detail. Currently, flow cytometry has been widely and successfully used in various fields of basic science research and clinical medicine. This FCM technology also can be used to study the cytotoxicity of dental materials and evaluate the biocompatibility of dental materials.[5-6] The contents of the study were (1) cytotoxicity assay on dental material HEMA monomer in human dental pulp cells by MTT method. (2) application flow cytometry to analyze the effect of dental material HEMA monomer on the cell cycle progression of the human dental pulp cells.

Cell Cycle↗
PubMed1999

[The model of piggyback orthotopic liver transplantation in pigs].

To establish the pig model of piggyback orthotopic liver transplantation(PBOLT), twelve cases of pig PBOLT were performed. The result showed that ten pigs were survived after operation, and the operative successful rate was 83%. The mean operation time and mean anhepatic-phase time were 7 hours and 34 minutes, respectively. The mean bleeding amount was 1200 ml. The appearance and tissue structure of liver in every stage under optic microscope were normal. The results indicate that the pig model of PBOLT is feasible and that it is important to decrease the anhepatic-phase time for a successful liver transplantation.

Animals↗
PubMed1999

[Piggyback allogenic orthotopic liver transplantation: one case report].

Piggyback allogenic orthotopic liver transplantation was performed successfully on one patient with primary liver carcinoma. The operation took 11 h and 30 min. The resection of the liver in the patient was initiated by the ligation and transection of the veins within the third hepatic portal. The hepatic venous system was reconstructed with the end of the superhepatic inferior vena cava anastomosed to the side of the inferior vena cava at the angle of 30 degrees-45 degrees in the recipient. The hemodynamics was steadfast intraoperatively, without extracorporeal venous bypass. The patient had a good post-operative recovery. The patient died of respiratory failure caused by metastasis.

Adult↗
PubMed1997

[Identification of photoproducts for PCB congeners by the new retention index system].

Polychlorinated biphenyls (PCBs) are a kind of priority pollutants, constituting a complex group of 209 congeners ranging from monochloro to decachlorobiphenyls. Because of the shortcomings of retention time data and the lack of suitable retention index systems, the congeners analysis of PCBs is one of the most challenging tasks in capillary column gas chromatography (GC), especially due to the fact that the isomers of PCBs can not be identified by GC-MS. A new retention index system, suitable for analysis of PCB congeners in the environmental samples by temperature-programmed capillary gas chromatography with ECD, has been developed recently by Chu et al. In this paper, retention indexes of all 209 PCB congeners were calculated according to the new retention index system from their respective retention times reported by other authors. The photoproducts of PCB87, PCB138 and PCB169 were identified with the new retention index system and confirmed by GC-MS. The deviations of retention indexes for all photoproducts were within 3 index units. It was testified that the above retention index system was reliable during the identification of PCB congeners and would have wide applicability. Based on the formations of coplanar PCB congeners (PCB77 and PCB126) during the photodegradations of PCB138 and PCB169, it was proposed that toxic equivalence (TEQ) should be used as a kind of quality indicator for the studies of the photolysis of PCBs.

Chromatography, Gas↗
PubMed1996

[Effects of electret and Ligusticum wallichii (chuangxiong) on the functional recovery of muscle grafts].

The aim of this study was to evaluate the effects of electret and Ligusticum wallichii (Chuangxiong, a traditional Chinese herb medicine) on the functional recovery of muscle grafts. Twenty-eight adult dogs were divided into 4 groups with each consisting of 7 animals. After orthotopical transplantation of bilateral rectus femoris muscle with neurovascular anastomosis, group A received electret local implant, group B received Chuangxiong injection, group C received both electret local implant and Chuangxiong injection and group D was used as control. The results showed that the functional recovery of the transplanted rectus femoris muscle in group A and B was better than group D while group C was the best. At 22 postoperative weeks, the recovery rate of maximal tetanic tension was 64.94 +/- 3.82% in group c: 57.68 +/- 1.67% in group A, 53.64 +/- 3.82% in group B and 47.99 +/- 2.21% in group D (P < 0.05). The structural recovery of the transplanted muscle in group C was closest to the normal.

Action Potentials↗
PubMed1995

[Study on CCK-induced gallbladder emptying with real-time ultrasonography].

In the present study, we adopted real-time ultrasonography to investigate the effect of atropine on the gallbladder emptying induced by CCK-OP in the normal subjects, and the difference of gallbladder emptying induced by CCK-OP between the "silent" gallstone patients and the controls. The results showed that: (a) CCK-induced gallbladder emptying in normal subjects was inhibited from 88.7% +/- 5.5% without atropine to 43.4% +/- 9.4% with atropine (P < 0.001). (b) The fasting gallbladder volume in the "silent" gallstone patients (26.7 +/- 10.9cm3) was significantly larger than that in the control (19.2 +/- 7.3cm3) (P < 0.05) and gallbladder emptying in the "silent" gallstones patients (44.0% +/- 8.7%) was significantly lower than that in the control (53.4% +/- 6.4%) (P < 0.01). We concluded that, significantly inhibited CCK-induced gallbladder emptying and there was significantly impaired gallbladder emptying in the patients with gallstones.

Adult↗
PubMed1994

p53 mutations in human bladder cancer.

Mutations in the tumor suppressor gene p53 play an important role in carcinogenesis and tumor progression. To assess the status of p53 from genomic DNA from bladder cancer samples a two stage polymerase chain reaction was employed. The technique provided material for subsequent detection of mutations by Single Strand Conformation Polymorphism (SSCP) analysis followed by DNA sequence analysis. SSCP analysis of exons 5 to 9 of p53 was performed using fragments from PCR end-labeled with 32P followed by autoradiography using an electrophoresis system with temperature control. This SSCP method improved resolution of mutations in exons 5, 7, and 8 and the sharpness of bands in exons 6 and 9. Bands with altered migration patterns were excised from the dried SSCP gels, reamplified by PCR, and sequenced. Mutations in conserved exons 5, 6, 7, 8, and 9 of the p53 gene were analyzed from bladder tumor biopsies. Our results are consistent with the literature in that mutations in p53 are predominantly found in high grade bladder cancer (Odds Ratio = 4.05, Fisher Exact P = 0.104); however, the results were not statistically significant due to small numbers. Eight of 35 (23%) tumor samples examined showed mutations in p53 (including two double mutations). Six of 13 (46%) grade III and IV tumors had p53 mutations vs. 2 of 17 (12%) grade I and II tumors. Normal individuals carried no p53 mutations. We found no correlation between pack years of smoking and mutation in p53. The spectrum of mutations confirmed a high proportion of G:C C:G transversions as well as the occurrence of double mutations.

Autoradiography↗