Biomedical subjects

Qiang Du

Publications and source records attributed to Qiang Du.

7 recordsLinked to original sources

PubMed2006

Identification of a classic cytokine-induced enhancer upstream in the human iNOS promoter.

The human inducible NOS (iNOS) promoter transcriptionally regulated by 5' flanking region extending 16 kb upstream that contains cytokine-responsive DNA motifs. In this study, we further identified a classic inducible enhancer located between -5 and -6 kb in the hiNOS upstream promoter. This 1 kb promoter sequence functions as a cytokine-inducible enhancer in an orientation- and position-independent manner in human lung A549 and liver AKN1 cells. This DNA enhancer also confers cytokine inducibility to the heterologous thymidine kinase (TK) promoter. Chromatin immunoprecipitation (ChIP) analysis was applied, and confirmed cytokine-inducible in vivo DNA-protein interactions within this enhancer region. In vivo functional binding of both NF-kappaB (p65/p50) and Stat-1alpha at the -5.8 kb human iNOS promoter site was significantly increased in A549 cells after cytokine stimulation, while only Stat-1alpha bound at the -5.2 kb site. These results identify the -5 to -6 kb promoter region as a classic transcriptional enhancer for the human iNOS gene and provide definitive in vivo evidence of specific NF-kappaB and Stat-1 nuclear protein binding that mediates transcription of the hiNOS gene under cytokine stimulation.

Binding Sites↗

PubMed2006

Regulation of human nitric oxide synthase 2 expression by Wnt beta-catenin signaling.

Nitric oxide (NO.), an important mediator of inflammation, and beta-catenin, a component of the Wnt-adenomatous polyposis coli signaling pathway, contribute to the development of cancer. We have identified two T-cell factor 4 (Tcf-4)-binding elements (TBE1 and TBE2) in the promoter of human inducible NO synthase 2 (NOS2). We tested the hypothesis that beta-catenin regulates human NOS2 gene. Mutation in either of the two TBE sites decreased the basal and cytokine-induced NOS2 promoter activity in different cell lines. The promoter activity was significantly reduced when both TBE1 and TBE2 sites were mutated (P < 0.01). Nuclear extract from HCT116, HepG2, or DLD1 cells bound to NOS2 TBE1 or TBE2 oligonucleotides in electrophoretic mobility shift assays and the specific protein-DNA complexes were supershifted with anti-beta-catenin or anti-Tcf-4 antibody. Overexpression of beta-catenin and Tcf-4 significantly increased both basal and cytokine-induced NOS2 promoter activity (P < 0.01), and the induction was dependent on intact TBE sites. Overexpression of beta-catenin or Tcf-4 increased NOS2 mRNA and protein expression in HCT116 cells. Lithium chloride (LiCl), an inhibitor of glycogen synthase kinase-3beta, increased cytosolic and nuclear beta-catenin level, NOS2 expression, and NO. production in primary human and rat hepatocytes and cancer cell lines. Treatment with Wnt-3A-conditioned medium increased beta-catenin and NOS2 expression in fetal human hepatocytes. When administered in vivo, LiCl increased hepatic beta-catenin level in a dose-dependent manner with simultaneous increase in NOS2 expression. These data are consistent with the hypothesis that beta-catenin up-regulates NOS2 and suggest a novel mechanism by which the Wnt/beta-catenin signaling pathway may contribute to cancer by increasing NO. production.

Animals↗

PubMed2006

[Six cases of adenoid cystic carcinoma in external auditory canal].

OBJECTIVE: By investigating the clinical and pathological features of adenoid cystic carcinoma in external auditory canal, we can improve our ability of diagnosis and treatment. METHOD: A retrospective analysis was performed on 6 patients with adenoid cystic carcinoma in external auditory canal, including clinical manifestations, the therapy as well as the follow-up results. All cases underwent subtotal temporal bone resection or other aggressive surgical excision. RESULT: All cases were alive for a period from 8 to 21 months after subtotal temporal bone resection or other aggressive surgical excision, without any signs of regional lymph node metastasis and distal metastasis. CONCLUSION: Adenoid cystic carcinoma in external auditory canal grows slowly, so patients can live with the tumor for a long time. But the long-term prognosis is poor. It is necessary to manipulate aggressive surgical excision at the first time to improve cure rate.

Adult↗

PubMed2006

[Prognostic factors identified by Cox multivariate analysis of surgically treated 1018 laryngeal cancer patients].

OBJECTIVE: To study the prognostic factors of 1018 patients with laryngeal cancer treated surgically. METHODS: All patients were treated surgically for laryngeal cancer from 1984 to 1996. A total of 16 clinical factors was studied by univariate analysis and Cox multivariate model. RESULTS: The follow-up rate was 93.5% over 5 years. The overall cumulative survival rate was 79.1% at 3 years, 70.2% at 5 years. The 5-year survival rate of T1N0 is the highest, followed by T1N+, T2N0, T3N0, T4N0, T2N+, T4N+, and T3N+. In univariate analysis, the survival was related to patient age, mobility of vocal cords, preoperative T status, preoperative N status, preoperative UICC stage, postoperative T status, postoperative N status, postoperative UICC stage, topographic location of the tumor and tumor size. In Cox multivariate modal, only postoperative N status, mobility of vocal cords and tumor size were independent prognostic factors. CONCLUSION: Independent prognostic factors for patients with laryngeal cancer after curative resection are postoperative N stage, mobility of vocal cords as well as tumor size. Postoperative follow-up and salvage surgery in time should be attached with importance to improve the survival of patients with laryngeal cancer.

Adult↗

PubMed2004

[Survival analysis of 1115 patients with laryngeal carcinoma].

OBJECTIVE: To study the long-term result of patients with laryngeal carcinoma treated by surgery and the prognostic factors. METHODS: The survival status of 1115 patients with laryngeal carcinoma which were treated in this department between 1983 and 1996 were retrospectively investigated. RESULTS: Overall 5-year survival rate was 77%. Among them, 5-year survival rate for patients of stage I was 94%, stage II 89%, stage III 82%, stage IV 66%. Patients with glottic cancer had the best prognosis, followed by supraglottic, subglottic and transglottic cancer. Five years survival rate for patients with partial laryngectomy was 85%, whereas, for total laryngectomy was 68%. The causes of failure were local recurrence and metastasis(70%). 14% of dead was not clear. CONCLUSION: Early diagnosis was the key for both larynx preservation and survival rates. Causes of dead were laryngeal recurrence and metastasis.

Adult↗

PubMed2003

Dissipative flow and vortex shedding in the Painlevé boundary layer of a Bose-Einstein condensate.

This paper addresses the drag force and formation of vortices in the boundary layer of a Bose-Einstein condensate stirred by a laser beam following the experiments of Phys. Rev. Lett. 83, 2502 (1999)]. We make our analysis in the frame moving at constant speed where the beam is fixed. We find that there is always a drag around the laser beam. We also analyze the mechanism of vortex nucleation. At low velocity, there are no vortices and the drag has its origin in a wakelike phenomenon: This is a particularity of trapped systems since the density gets small in an extended region. The shedding of vortices starts only at a threshold velocity and is responsible for a large increase in drag. This critical velocity for vortex nucleation is lower than the critical velocity computed for the corresponding 2D problem at the center of the cloud.

Journal Article↗

PubMed2002

[A study of forensic DNA databases].

OBJECTIVE: The forensic DNA databases are very important for individual identification. In order to evaluate the genetic markers used for a forensic DNA databases and the compatibility between the manual DNA typing system and the automatic DNA typing system, a testing DNA database should be constructed. Also, constructing a testing DNA database can increase our understanding of the issue for forensic DNA databases. METHODS: A total of 1000 specimens, including samples of blood, blood stains, salvia stains, semen stains, mixture stains and muscle tissues, were collected from the public security bureau of Chengdu. The DNA of each specimen was extracted by Chelex method and analyzed using Amp-FLP technique. A total of 8 STR loci, including D3S1358, D9S1118, vWA, D5S818, D16S539, D8S1179, CSF1PO and D20S161 were chosen and employed for DNA typing. Each STR locus was amplified by the polymerase chain reaction PCR and the PCR products were typed with the polyacryamide gel electrophoresis. Typing DNA was carried out by comparing with a human allele ladder. A total of 8 human allele ladders for D3S1358, D9S1118, vWA, D5S818, D16S539, D8S1179, CSF1PO and D20S161 were made in-house. Managing software of the testing DNA database was designed using Microsoft Access. RESULTS: The results of DNA typing in 1000 specimens showed that the total discrimination power of 8 STR loci was over 0.99999999. CONCLUSION: This study show that a forensic DNA database should be useful for search purpose. The total discrimination power over 0.99999999 imply that in principle there is no identical genotype at whole 8 STR loci between two persons from a population with 10000000 individuals. This means that 8 STR loci used in this study are suitable to construct forensic DNA databases in Chengdu of China. The result of DNA typing can be repeated and the data have compatibility between the manual DNA typing system and the automatic DNA typing system. The data search in our testing DNA database can be carried out using only some loci of the set of 8 STR markers. Also, the volume of our testing DNA databases could be enlarged easily. The implication from this study is that the legislation should not be negligent before establishing a forensic DNA database. This DNA database provides a model for establishing the forensic DNA databases in China.

Adolescent↗