PubMed Health⌕ Search

Biomedical subjects

Guohua Zhou

Publications and source records attributed to Guohua Zhou.

9 recordsLinked to original sources
PubMed2006

Association of IL1B polymorphisms with gastric cancer in a Chinese population.

OBJECTIVES: To investigate the association between IL1B polymorphisms and risk of gastric cancer in a Chinese population, seven SNPs in the IL1B gene were selected for this study. METHODS: A multiplex genotyping method, which is based on adapter ligation and allele-specific amplification, was established to type seven SNPs on the IL1B gene simultaneously. One hundred and forty-one non-cancer outpatients and 97 patients with gastric cancer were genotyped, and the relation between IL1B polymorphisms and gastric cancer was statistically analyzed. RESULTS: The seven SNPs were successfully typed and the results were consistent with those obtained by both Sanger's sequencing and PCR-RFLP. Handling with statistical analysis, we observed significantly different genotype frequencies of 0794C>T (chi(2)=6.11, P=0.05), 1274C>T (chi(2)=6.86, P=0.03) and 2143T>C (chi(2)=6.86, P=0.03) between patients and controls. CONCLUSION: ALM-ASA is a potential method for multiplex SNP typing with a low consumption of genomic DNA. SNPs 0794C>T, 1274C>T, and 2143T>C are associated with gastric cancer.

Adolescent↗
PubMed2006

Enzyme system for improving the detection limit in pyrosequencing.

Highly sensitive real-time pyrosequencing seems promising for constructing an inexpensive and small DNA sequencer with a low running cost. A DNA sample of a picomole level is usually used in the conventional pyrosequencing based on a luciferase assay coupled with an APS-ATP surfurylase reaction for producing ATP from pyrophosphate (PPi). Although the luminescence intensity could be increased by increasing the amount of luciferase, it was impossible to reduce the target DNA amount because of a large background luminescence due to the luciferase-APS reaction. In this report, a novel approach using a new conversion reaction of PPi to ATP is proposed. This method has a very low background and can produce high signals in the presence of a large amount of luciferase; thus, the sample amount required for sequencing is significantly reduced. The ATP production from PPi is catalyzed with pyruvate orthophosphate dikinase (PPDK) using AMP and phosphoenolpyruvate as the substrates, which are inactive for the luciferase-catalyzed reaction. All of the components in the AMP-PPDK-based pyrosequencing system are suitable for highly sensitive DNA sequencing in one tube. Real-time DNA sequencing with a readable length up to 70 bases was successfully demonstrated by using this system. By increasing the amount of luciferase, as low as 2.5 fmol of DNA templates was accurately sequenced by the proposed method with a novel simple and inexpensive DNA sequencer having a photodiode array as a sensor instead of a PMT or CCD camera. A sample amount as low as 2 orders of magnitude smaller than that used in the conventional pyrosequencer can be used.

Enzymes↗
PubMed2005

The expression of functional chemokine receptor CXCR4 is associated with the metastatic potential of human nasopharyngeal carcinoma.

PURPOSE: Chemokine receptors are implicated in metastasis of several malignant tumors. This study was done to evaluate the contribution of chemokine receptors CXCR4 and CCR7 to metastasis of human nasopharyngeal carcinoma. EXPERIMENTAL DESIGN: Reverse transcription-PCR, immunohistochemistry, and flow cytometry were used to evaluate mRNA and protein expression of CXCR4 and CCR7 in nasopharyngeal carcinoma tumor tissues and cell lines. Chemotaxis assays were used to evaluate the function of CXCR4 in nasopharyngeal carcinoma cells. Antisense CXCR4 was used to inhibit receptor expression and to block metastasis of human nasopharyngeal carcinoma cells in vivo in athymic mice. RESULTS: CXCR4 protein was detected in tumor cells in 31 of 40 primary human nasopharyngeal carcinoma and in 13 of 15 lymph node metastases. CXCR4 transcripts were detected in eight CXCR4 protein-positive primary nasopharyngeal carcinoma tissues and seven nasopharyngeal carcinoma cell lines tested. On the other hand, the transcripts for CCR7 were detected only in four primary nasopharyngeal carcinoma tissues and in none of the nasopharyngeal carcinoma cell lines. In functional experiments, metastatic nasopharyngeal carcinoma cell lines that expressed high levels of CXCR4 were found to migrate in response to the CXCR4 ligand SDF-1alpha. Transfection of antisense CXCR4 in metastatic nasopharyngeal carcinoma cells inhibited the expression of CXCR4 and SDF-1alpha-induced cell migration in vitro and reduced the capacity of the tumor cells to form metastasis in the lungs and lymph nodes when injected in athymic mice. CONCLUSION: The expression of functional CXCR4 but not CCR7 is correlated with the metastatic potential of human nasopharyngeal carcinoma cells. Therefore, CXCR4 may be considered as a potential target for the prevention of nasopharyngeal carcinoma metastasis.

Animals↗
PubMed2005

Transduction of the gene coding for a human G-protein coupled receptor FPRL1 in mouse tumor cells increases host anti-tumor immunity.

Low antigenicity or development of tolerance is believed to be a major contributor to the escape of malignant tumors from immune surveillance of the host. However, anti-tumor responses can be elicited by concomitant immunization of poorly antigenic tumor cells with homologous xenogeneic proteins as 'altered self' proteins. In our study, anti-tumor, but not anti-xenogeneic antigen, immune responses were generated after transduction of the gene coding for a G-protein coupled human formyl peptide receptor like-1 (FPRL1) into a mouse C26 colon cancer cell line. C26 cells transfected with FPRL1 gene exhibited markedly reduced tumorigenicity in syngeneic mice, in association with the appearance of high levels of antibody activity reacting with both FPRL1 containing and wild type C26 cells. The anti-tumor responses required the participation of CD4+ T lymphocytes, since no tumor rejection was observed in nude mice or in syngeneic mice depleted of CD4+ T cells. Furthermore, mice primed with FPRL1 transfected C26 cells were resistant to subsequent challenge by wild type C26 cells. These results indicate that the presence of human FPRL1 is capable of triggering specific anti-tumor host immune responses against poorly antigenic mouse tumor cells.

Animals↗
PubMed2005

Assembly fabrication of oligonucleotide arrays.

In this paper, a simple, reliable and flexible method for fabricating oligonucleotide arrays integrating in in-situ synthesis with a spotting technique is described. In this approach, different oligonucleotide sequences were synthesized on coded modification glass slides using combinatorial chemistry and a mature phosphoramidite chemistry protocol. The slides were then sliced into smaller pieces. Finally, an oligonucleotide array was fabricated by arbitrarily assembling the different coded pieces onto another solid support. A 5 x 5 array including four different sequences of the P16 gene and a control (blank) was successfully assembled. The results indicated that the hybridization fluorescence intensities from the same sequences located at different places on the array were homogeneous and uniform. Background fluorescence was much lower. The fluorescence intensity ratio of a matched sequence to a one-base mismatched sequence, a two-base mismatched sequence and a three-base mismatched sequence was 0.499, 0.236 and 0.04, respectively. The results for the same sequence at different spots in the chip were reproducible with the relative standard deviation ranging from 6.64% to 10.2% (n = 5). This method has the advantages of high probe-density of in-situ synthesis, and off-chip flexibility. Moreover, it does not need any immobilization process to bond oligonucleotides on the substrate.

Base Sequence↗
PubMed2004

Water reduction and oxidation on Pt-Ru/Y2Ta2O5N2 catalyst under visible light irradiation.

Y(2)Ta(2)O(5)N(2) is presented as a novel photocatalyst with high activity for water splitting under visible-light irradiation in the presence of appropriate sacrificial reagents; the activity for reduction to H(2) is increased by the incorporation of Pt or Ru as a co-catalyst, with a significant increase in production efficiency when both Pt and Ru are present.

Journal Article↗
PubMed2002

Active immunotherapy with anti-idiotypic antibody for patients with nasopharyngeal carcinoma (NPC).

Two anti-idiotypic monoclonal antibodies (Ab2), designated 2H4 and 5D3, against two antitumor antibodies Ab1 (FC2 and HNL5) that recognize nasopharyngeal carcinoma (NPC) associated antigen were generated. They could substitute NPC antigen to induce humoral and cellular immune response against NPC cells in syngeneic mice. Nineteen patients with NPC at stage IV were chosen for active immunotherapy. They were treated with aluminum hydroxide-precipitated Ab2 2H4 or 5D3 accompanying radiotherapy. None of the immunization of anti-idiotypic monoclonal antibody (mAb) was associated with toxicity or allergies reactions. Nine patients with radiotherapy alone served as control. Both anti-anti-idiotypic antibodies (Ab3) and anti-NPC antibodies (Ab1') were increased and human anti-mouse Ig antibodies (HAMA) occurred in nineteen patients of the experimental group; whereas the levels of Ab1' did not rise in the control group. Serum IL-2, IFN-gamma, and TNF-alpha levels were increased in most patients in the experimental group, while in the control group, there were no differences of Ab1' and cytokine level between pretherapy and posttherapy. In addition, IL-2 mRNA expression in peripheral blood mononuclear cells (PBMC) of NPC patients was closely related to serum IL-2 (r = +0.8829) by in situ hybridization. Therefore, mouse anti-idiotypic antibodies 2H4 and 5D3 are safe for active immunotherapy and might enhance humoral and/or cellular immunity of NPC patients receiving radiotherapy.

Adult↗
PubMed2002

A clinical trial of active immunotherapy with anti-idiotypic vaccine in nasopharyngeal carcinoma patients.

OBJECTIVE: To investigate the effect of active immunotherapy with anti-idiotypic vaccine in patients with nasopharyngeal carcinoma (NPC). METHODS: Anti-idiotypic antibodies (2H4/5D3) bearing the internal image of the NPC antigen were used in active immunotherapy in NPC patients receiving radiotherapy. Antibodies and cytokine levels in patient sera were determined using ELISA before and after active immunotherapy. IL-2 mRNA expression in the peripheral blood mononuclear cells (PBMC) was measured by in situ hybridization. RESULTS: Nineteen patients with NPC at stage IV were treated with alum-precipitated 2H4 or 5D3. Neither hypersensitivity nor adverse side effects were observed. The levels of anti-anti-idiotypic antibodies (Ab3) and anti-NPC antibodies (Ab1') were increased. Human anti-mouse antibodies (HAMA) were seen in 19 patients of the experimental group; the levels of Ab1' did not increase in the control group. Serum IL-2, IFN-gamma and TNF-alpha levels were increased in most patients in the experimental group, while no differences were observed in Ab1' and cytokine levels between pre- and post-therapy in the control group. In addition, IL-2 mRNA expression in PBMCs from NPC patients was closely related to serum IL-2 (r = + 0.8829) levels by in situ hybridization. CONCLUSIONS: Anti-idiotype vaccine is safe for clinical active immunotherapy. Anti-idiotypic vaccine might be able to enhance humoral and/or cellular immunity in NPC patients receiving radiotherapy.

Adult↗