Biomedical subjects

Qing-Hua Wu

Publications and source records attributed to Qing-Hua Wu.

11 recordsLinked to original sources

PubMed2005

[Correlation between methylation of 5'-CpG islands and inactivation of FHIT gene in cervical cancer].

BACKGROUND & OBJECTIVE: Fragile histidine triad (FHIT) gene, a tumor suppressor gene, correlates with tumorigenesis of many solid tumors, and may be inactivated via methylation. This study was designed to explore relationship of methylation of 5'-CpG islands with inactivation of FHIT gene in cervical cancer. METHODS: Methylation of 5'-CpG islands in 10 normal cervical squamous epithelial tissues, and 40 cervical cancer tissues was detected with methylation specific polymerase chain reaction (MSP), protein expression of FHIT was detected with immunohistochemistry, and their correlations with clinicopathologic features of cervical cancer were statistically analyzed. RESULTS: (1) The 5'-CpG islands methylation rate of FHIT gene in cervical cancer tissues was 40.0% (16/40), while no methylation of FHIT gene was found in normal cervical tissues. (2) The methylation rates of FHIT gene in cervical cancer of stage I was 14.3% (2/14), significantly lower than that in cervical cancer of stage II (56.5%, 13/23) (P<0.05). (3) Expression of FHIT protein in cervical cancer was 33.0% (12/40), significantly lower than that in normal cervical tissue (100%, 10/10) (P<0.05). CONCLUSION: The 5'-CpG islands methylation may play an important role in inactivation of FHIT gene, and may be related with tumorigenesis of cervical cancer.

Acid Anhydride Hydrolases↗

PubMed2005

[Oligonucleotide microarray for human immunodeficiency virus detection].

OBJECTIVE: To develop an oligonucleotide microarray for fast detection of human immunodeficiency virus (HIV). METHODS: With complete genome sequence of HIV-1 subtype B (U26942) as the target sequence and bioinformatics software such as DNAClub, Oligo6.0, BLAST, Alignment, oligonucleotide probes of high specificity with identical length and similar melting temperature (T(m)) were designed and synthesized. Oligonucleotide microarray was prepared using Cartesian Microarrayer. Using the plasmids of HIV-1 subtype B(U26942), C(U46016), F(AF075703), G(AF061640) and restriction display technique, Cy3-labeled HIV DNA fragments were amplified and the hybridization results were scanned and analyzed with Array-Pro. RESULTS AND CONCLUSION: Twenty-two optimized oligonucleotide microarray probes were obtained and used to prepare the oligonucleotide microarray for further screening studies. The microarray prepared significantly enhanced the sensitivity, reliability and speed of DNA assay, and possesses the potential for application in clinical setting.

Base Sequence↗

PubMed2005

[Application of oligonucleotide microarray primer extension to detection of p53 single nucleotide polymorphisms].

BACKGROUND & OBJECTIVE: Increasing evidences imply that single nucleotide polymorphisms (SNPs) are involved in etiopathology, individual therapy, and prognosis of many diseases. Rapid and accurate SNPs detection in disease genes is vitally important for genomic research. To detect p53 SNPs, the method of an arrayed primer extension based on oligonucleotide microarray was developed. METHODS: Twelve extension primers were designed in exon 3 of p53 gene. These primers were synthesized and printed onto a microarray with 7x8 spots. The fragments of p53 DNA were extracted from K562 cells by nested polymerase chain reaction (PCR), and hybridized with the microarray. After hybridization, the primer extension reactions were carried out with DNA polymerase Klenow, labeled with Cy3-dUTP or Cy5-dCTP; the product was washed and scaned, and the fragments of p53 was sequenced by ABI3730 DNA Analyzer. RESULTS: The scanning result showed that the primer extension reactions were successful, and single base labeled with Cy3 or Cy5 was extended correctly at the end of 3'primers. The results of microarray SNPs detection were consistent with the results of sequencing verification, while much less complicated. CONCLUSION: These results indicate that the arrayed primer extension techniques are useful in parallel detecting SNPs of genes of interest, which is not only sensitive and accurate but also miniaturized the assays when analyzing multiple DNA targets with minimal reagents.

DNA Primers↗

PubMed2005

[Expression and clinical significance of endostatin and vascular endothelial growth factor in ovarian carcinoma].

BACKGROUND & OBJECTIVE: Vascular endothelial growth factor (VEGF) can induce angiogenesis, tumorigenesis, invasion, and metastasis of tumors; while endostatin has opposite functions. This study was designed to explore the expression of endostatin and VEGF in epithelial ovarian cancer, and investigate their correlations to oncogenesis and progression of ovarian cancer. METHODS: The mRNA and protein levels of endostatin and VEGF in 63 samples of epithelial ovarian cancer and 19 samples of normal ovarian tissue were detected with reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry. RESULTS: The mRNA levels and positive rates of endostatin and VEGF proteins were significantly higher in epithelial ovarian cancer than in normal ovarian tissue (P<0.05), and were significantly higher in stage III-IV ovarian cancer than in stage I-II ovarian cancer (P<0.05). Positive rate of endostatin protein was significantly lower in endostatin mRNA level of < or =0.5 group than in endostatin mRNA level of >0.5 group (29.4% vs. 77.8%, P<0.05); positive rate of VEGF protein was significantly lower in VEGF mRNA level of < or =0.5 group than in VEGF mRNA level of >0.5 group (25.0% vs. 72.0%, P<0.05). CONCLUSIONS: The changes in mRNA levels of endostatin and VEGF in epithelial ovarian cancer are accordant to the changes in positive rates of the proteins. The imbalance between VEGF and endostatin may be related with tumorigenesis and development of epithelial ovarian cancer.

Adult↗

PubMed2002

[Purification of PCR products with cetyltrimethylammonium bromide].

OBJECTIVE: To establish a method for purifying PCR products with cetyltrimethylammonium bromide (CTAB). METHOD: Selective precipitation of the PCR product was performed using CTAB, which forms compound with DNA fragment in salt solution of appropriate concentration, but not with single strain oligonucleotide or dNTPs. The precipitation could be dissolved in 1.2 mol/L NaCl while the addition of ethanol caused the desired PCR product to precipitate so as to be recovered. RESULT: The primers and small-molecule dNTP could be effectively eliminated after this procedure. Although the output of the purification process reached only 80% that by current reagent kit, it reduces the cost to as low as 1/8 of that normally required by the kit. CONCLUSION: CTAB is applicable for purification of the PCR product.

Cetrimonium↗

PubMed2002

[Cloning E. coli mRNAs with poly (A) tails by restriction digest polymerase chain reaction].

OBJECTIVE: To investigate the polyadenylation at the 3' terminal of the mRNAs in E.coli. METHODS: mRNAs of E.coli was enriched from total RNA with oligo (dT)-cellulose, and reverse transcription was performed using oligo(dT)18 as primer prior to synthesis of double strands cDNA which was digested with Sau 3A I to produce multiple gene fragments that were then ligated with adapters. Restriction digest-polymerase chain reaction (RD-PCR) was employed to divide the fragments into 10 groups using 10 different combinations of the 4 primers, and the products were cloned into T-vectors. RESULTS: More than 100 gene fragments were cloned, 30 of which were sequenced. CONCLUSION: Polyadenylation of E.coli mRNA is not a biochemical curiosity, and very likely, it is a general attribute of the mRNAs of bacteria.

Base Sequence↗

PubMed2002

[Effect of probe purification on the reutilization of gene chip].

OBJECTIVE: To investigate the effect of probe purity on the reutilization of gene chips. METHODS: Purified and unpurified probes were respectively hybridized with the gene chip and after being scanned with Scanarry lite, a laser scanning device, the gene chip was treated with stripping solution to wash off the probes. After another round of scanning under the same condition to obtain the images, the gene chip was recycled for another hybridization. RESULTS: Hybridization of unpurified probes resulted in high background noise and obscure positive signals, which were present even after wash with stripping solution for 4 times. Hybridization using purified probes, in contrast, presented low background noise that was completely eliminated after the gene chip was washed twice before it was used again. CONCLUSION: The purity of probes is of great importance to the recycling of the gene chips, and hybridization with unpurified probes renders the chips impossible for reutilization.

DNA, Complementary↗

PubMed2002

[Detection of cell apoptosis by MTT assay].

OBJECTIVE: To study the feasibility of using MTT assay to detect cell apoptosis. METHODS: K562 cells were grown in RPMI 1640 medium supplemented with 10% calf serum and 4 micromol/L arsenic trioxide. Apoptosis was induced in the cultured cells by As2O3, and the cells were detected with optical microscope, DNA gel electrophoresis and MTT staining respectively. RESULT: MTT staining could also accurately detect cell apoptosis, by which the apoptotic cells were easily distinguished from normal cells and dead cells. CONCLUSION: MTT staining is simple, convenient and practical for detecting cell apoptosis.

Antineoplastic Agents↗

PubMed2002

[Construction and identification of cDNA library of E.coli mRNA with poly(A) tracts].

OBJECTIVE: To construct and identify the cDNA library of E.coli mRNA with poly(A) tracts. METHODS: The cDNA library of E.coli was constructed by restriction display-PCR (RD-PCR) technique, followed by sequencing and bioinformatics analyses. RESULTS: cDNA library of E.coli mRNA with poly(A) tracts was successfully constructed, and 66 gene fragments were sequenced. CONCLUSION: The constructed cDNA library of E.coli mRNA with poly(A) tracts contains a low rate of repetition and is of high quality.

Cloning, Molecular↗

PubMed2001

Cloning and sequence analysis of HIV-1 gene fragments isolated by restriction digest polymerase chain reaction method.

OBJECTIVE: To clone and analyze the HIV-1gene fragments isolated by restriction digest polymerase chain reaction (RD-PCR). METHOD: All the HIV-1 gene fragments were divided into 10 subgroups and amplified by RD-PCR. The PCR products of each subgroup were purified and cloned into the T-vectors, then identified rapidly. The plasmids were extracted from positive clones and the target gene fragments were amplified and sequenced. RESULTS: Sequences analysis showed that all the fragments amplified were HIV gene. CONCLUSION: A method for cloning and identifying multiple fragments has been improved and used for restriction fragments.

Journal Article↗

PubMed2000

DNA Microarray Chips Made on Surface of Ceramic Slides.

As a novel technology, DNA microarray chips are being used in gene detections. To make DNA chips capable of multiple probing, ceramic slides, instead of silicon wafer or glass slides, were used as the substrate upon which DNA microarray are deposited. Our study indicates that the ceramic DNA microarray chips can be applied to multiple hybridization and detection procedures, showing high specificity. The advantages in using ceramic substrates are discussed.

Journal Article↗