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Biomedical subjects

Yan Li

Publications and source records attributed to Yan Li.

At least 217 records · Page 12Linked to original sources
PubMed2006

[Construction of recombinant adenovirus carrying human IFNgamma gene by in vitro ligation and its expression].

BACKGROUND & OBJECTIVE: Interferon-gamma (IFNgamma) can promote directly the apoptosis of some kinds of tumor cells and regulate cellular immunity, therefore, it may play an important role in gene therapy for tumors. This study was to construct recombinant adenovirus carrying human IFNgamma cDNA, and detect its expression profile in eukaryotic cells. METHODS: IFNgamma cDNA was amplified by reverse transcription-polymerase chain reaction (RT-PCR) from human peripheral blood mononuclear cells, and cloned into adenoviral shuttle plasmid pShuttle to construct recombinant adenovirus carrying human IFNgamma cDNA (Ad-IFNgamma) by in vitro ligation. Hepatocellular carcinoma cell line HepG2 was infected with Ad-IFNgamma, and the expression of IFNgamma was detected by RT-PCR and immunohistochemistry. RESULTS: The sequence of the cloned IFNgamma cDNA was completely consistent with that reported in GenBank. PCR analysis confirmed the existence of IFNgamma gene in Ad-IFNgamma without wild adenovirus contamination, and the genome of Ad-IFNgamma showed the predicted map of restricted endonuclease enzymes analysis. IFNgamma mRNA and protein were detected in HepG2 cells infected with Ad-IFNgamma. CONCLUSIONS: In vitro ligation is a simple and convenient method for construction of recombination adenovirus vector. We have constructed a functional recombinant adenovirus expressing human IFNgamma, which could be a potential antivirus and antitumor agent in vitro or in vivo.

Adenoviridae↗
PubMed2006

[Study on linkage between polymorphism of interleukin 6 gene -572C/G and susceptibility to myocardial infarction].

OBJECTIVE: To observe the polymorphism and gene frequency of interleukin 6 (IL6) gene -572C/G in Chinese Han nationality population, that associating with susceptibility to myocardial infarction(MI) and impacting on the extent of coronary artery lesions; to analyze the function of IL6 gene -572C/G polymorphism. METHODS: With PCR-RFLP method, IL6 gene -572C/G polymorphism was genotyped to 232 MI patients and 260 healthy adults. The effect of IL6 gene -572C/G polymorphism was observed to the extent of coronary artery lesions and the ability of IL6 production from peripheral blood mononuclear cells (PBMC). RESULTS: There was IL6 gene -572C/G polymorphism in Chinese Hans. -572CG+GG genotype and G allele were more frequent in patients than in controls (P< 0.01). The relative risk for G allele carrier to suffer from MI was 1.68 times of CC genotype individual (95%CI 1.17-2.41, P< 0.01). However, the distribution of IL6 gene -572C/G polymorphism was no significant difference among patients with single-vessel, two-vessel and three-vessel lesions (P> 0.05). After PBMC cultured for 24 hours, the IL6 concentration in supernatant was significantly higher in subjects with CG genotype than those with CC genotype (P< 0.05). CONCLUSION: IL6 gene -572G allele may be a genetic susceptibility factor to MI attack of Chinese Hans population, and related to the high expression of IL6.

Aged↗
PubMed2006

[Status and clinical implication of c-kit and PDGFRA mutations in 165 cases of gastrointestinal stromal tumor (GIST)].

OBJECTIVE: To investigate the status of c-kit and PDGFRA mutations of GIST in a the large sample of Chinese patients. METHOD: One hundred and sixty-five cases were evaluated for the presence of c-kit and PDGFRA mutations. Exon 9, 11, 13, 17 of c-kit and exon 12, 18 of PDGFRA were analyzed by PCR amplification and direct sequencing. RESULTS: Immunohistochemical demonstrations of KIT (CD117) were seen in 94% of the cases (155/165). Overall, c-kit mutations were identified in 76.1% (118/155) of CD117 positive cases: 67.1% (104/155) involving exon 11, 7.1% (11/155) involving exon 9, 1.3% (2/155) involving exon 13 and 0.6% (1/155) involving exon 17. The c-kit exon 11 mutations were mostly heterogeneous and clustered in the classic "hot spot" at the 5' end of the exon, including in-frame deletion and point mutation. The second "hot spots" were internal tandem duplications (ITD) at the 3' end of the exon, which were associated with female patient, older age, stomach location and low mitotic counts. The exon 9 mutations correlated with a distinct subset of GISTs involving the small bowel of young male patients. A new point mutation of L641P was identified in exon 13. PDGFRA mutations were present in 50% (5/10) of CD117-negative GISTs, all involving exon 18 with the majority of mutations being D842V. One novel in-frame deletion of IMHD mutation at codon 843 - 846 with S847T was identified. GISTs with PDGFRA mutations were often larger tumors arising from the omentum/mesentery of young male patients with high risk of aggressive behavior. CONCLUSIONS: The vast majority of GISTs in this study harbored c-kit and PDGFRA mutations, there were non-random relations between the gene mutation patterns and the locations of GISTs. It appears that Chinese GIST patients have some unique mutation patterns. It is necessary to evaluate the gene mutations status of GISTs to guide target therapy.

Adolescent↗
PubMed2006

[Long-term survival analysis in 170 cases of acute promyelocytic leukemia].

This study was aimed to investigate various factors influencing long-term survival in patients with acute promyelocytic leukemia. A single institutional retrospective study with long-term follow-up was performed to better define the prognostic factors and a rationale for the use of ATRA, chemotherapy, and As(2)O(3) in the treatment of newly diagnosed APL patients. Newly diagnosed patients with APL entering complete remission (CR) were followed up for 6 to 185 months (n = 170) from January 1990 to December 2004. Univariate and multivariate analysis of 8 potential factors influencing survival and prognosis were carried out with Log-Rank and Cox regression method, including sex, age, initial WBC count, the level of lactic hydrogenase (LDH), first induction regimen, time from induction therapy to CR, post-remission therapy, negative or positive rate of PML-RAR alpha and follow-up of reverse transcription-polymerase chain reaction (RT-PCR). The results showed that the estimated 5-year overall survival (OS) and relapse-free survival (RFS) were 80.9% +/- 4.0% and 71.0% +/- 4.0% respectively. The 23 patients relapsed at the median time of 15 months (6 - 70) after CR. Univariate analysis revealed that initial WBC count, first induction regimen, time from induction therapy to CR, type of post-remission therapy and persistent negative RT-PCR in remission were important prognostic factors for long-term survival. Multivariate study demonstrated that only type of post-remission therapy was associated with RFS and OS. It is concluded that the post-remission treatment combining ATRA, As(2)O(3) and chemotherapy would significantly improve the long-term survival of APL patients entering CR(1).

Adolescent↗
PubMed2006

[Anti-CD28 antibody costimulation enhances anti-CD3 antibody activating T cells and lowering TGF-beta expression in vitro].

In order to study how to activate T cells and their immunological characteristics, the anti-CD3 and anti-CD28 McAbs were used to stimulate PBMNC, then their related immunological changes, such as lymphocyte transformation function, the percentage of CD8(+)CD25(+) cells and TGF-beta expression were deleted by lymphocyte transformation assay, flow cytometry and RT-PCR respectively. The results showed that in costimulation with anti-CD28 antibody stimulation, the activity of anti-CD3 antibody was significantly enhanced, the ratio of CD8(+)CD25(+) cells of T cells was obviously increased, while TGF-beta expression was down-regulated. It was concluded that the anti-CD28 antibody costimulation could provide stimulatory signal II, which make T cells more active, while the expression of TGF-beta significantly down-regulated.

Antibodies, Monoclonal↗
PubMed2006

[Cloning, expression and identification of catalase of Helicobacter pylori].

AIM: To construct the recombinant plasmid containing catalase (KatA) of Helicobacter pylori (Hp), analyze its nucleic acid sequence, express it in E. coli and study its antigenicity. METHODS: KatA fragments were amplified from Hp chromosomal DNA by PCR. Its T-A was cloned, sequenced and compared with other HP strains on the GenBank. Then the gene cloned into pGEX-4T-1 fusion expression vector was expressed in E. coli and purified by GST-affinity chromatography. The purified product was used to identify 29 stains of mouse anti Hp monoclonal antibodies and analyze antigenicity with serum of Hp-infected patients by Western blot. RESULTS: KatA fragments were composed of 1,515 bp (GenBank No. DQ333889) and the nucleotide homology with other Hp strains on the GenBank was 96%-97%. 85 kDa of the recombinant KatA-pGEX-4T-1 was expressed in E. coli. 4 of 29 anti-Hp mouse monoclonal antibodies were against KatA. Western blot analysis proved that KatA was specifically recognized in the serum of Hp-infected patients. CONCLUSION: The recombinant KatA has original antigenicity. It is of great value to clinical sero-diagnosis and vaccine study of Hp.

Antibodies, Monoclonal↗
PubMed2006

[Prevalence of anti-human parvovirus B19 IgG antibody among blood donors in Jilin province].

BACKGROUND: To investigate the prevalence of the parvovirus B19 infection among the blood donors in Jilin province to provide the basic data to evaluate the epidemics of B19 virus in China. METHODS: Indirect ELISA was used to detect IgG antibody against parvovirus B19 in the sera from blood donors. RESULTS: In a total of 184 serum samples, IgG antibody was detected in 55.43% samples, antibody positive rate in female was significantly higher than that in male (P<0.05) and the positive rate peaked at 35-45 years age group. CONCLUSION: These data illustrate that the prevalence of the B19 antibody in blood donors of Jilin province was high, and it is therefore necessary to detect the B19 DNA to ensure the blood safety.

Adolescent↗
PubMed2006

[The calibration of instrument response function during passive FTIR measurement].

In order to obtain infrared spectral radiance distribution of some infrared sources, such as spectral radiant flux density, spectral radiant intensity, spectral radiance and spectral irradiance, the instrument response function under different conditions must be known. In the present paper, the calibration of instrument response function during passive FTIR measurement has been discussed. The experimental results illustrate that under different experimental conditions, the instrument response function varies not only with the temperature of the blackbody but also with the signal amplitude received by the infrared instrument. So, during passive FTIR measurement, the temperature and the emission signal amplitude of the source must be observed carefully in order to get satisfactory instrument response function.

English Abstract↗
PubMed2006

[Automated recognition of VOCs using artificial neural networks].

Quantitative analysis of FTIR spectra, which are seriously overlapped in the spectral bands, was studied by artificial neural networks. The optimum network was chosen by a new criterion, i. e. the degree of approximation. After the network was established, two kinds of spectra were resolved. It was demonstrated that accurate results could be obtained when two components were both included. In addition, the unknown spectrum could be identified and quantified. It was showed that the artificial neural network has excellent non-linear ability of solution. Meanwhile, the method provides an efficient approach to the identification and quantification of the unknown samples.

English Abstract↗
PubMed2006

[Microemulsion sensitized fluorophotometric determination of protein with probe of phenylfluorone-molybdenum (VI) complex].

The fluorescence spectral behavior of interaction of phenylfluorone(PF)-Mo(VI) and protein was investigated in Triton X-100 microemulsion medium at pH 2.0. A novel method for the determination of protein using phenylfluorone (PF)-Mo(VI) as a fluorescence spectrum probe was developed. Excitation and emission wavelengths are 465 and 525 nm, respectively. The effective factors and the optimum conditions have been studied, and the reducing value of fluorescence intensity is in proportion to the concentration of proteins in the range 0-6.00 microg x L(-1) for bovine serum albumin, 0-4.00 microg x L(-1) for human serum albumin, 0-5.00 microg x L(-1) for ovalbumin, and 0-4.00 microg x L(-1) for lysozyme. The Triton X-100 microemulsion was efficiently used to enhance the sensibility and stability of the system, and the limits of detection are 5.4, 5.2, 1.5 and 8.2 ng x L(-1), respectively. Most of foreign substances do not interfere with the determination, and this method has good selectivity and high sensitivity. It has been applied to the determination of proteins in the urine samples with satisfactory results.

Animals↗
PubMed2006

[Remote passive detection of flame temperature of solid propellant adulterating nanoparticles].

The flame temperature of three kinds of solid propellants was measured by passive remote sensing FTIR with the resolution of 1 cm(-1). These three kinds of solid propellants are adulterate nano-scale metal oxide particles, adulterate normal metal oxide particles, and propellant without any adulterations. The main components of the solid propellant are nitrocellulose and nitroglycerin. The metallic oxides, including 6 nm CuO, 56 nm Fe2O3, 16 nm NiO, and correspondingly the normal particles, were adulterated into the solid propellants respectively. The flame temperature was calculated through the fine structure of the emission fundamental band of H2O at 2.75 microm. The results of the flame temperature of the solid propellants adulterating nano-scale CuO, Fe2O3 and NiO are 3089, 3193 and 3183 K, respectively. The temperatures of the three kinds of solid propellants were compared, and it was shown that there is no obvious difference in the flame temperature among the three kinds of solid propellants.

English Abstract↗
PubMed2006

[Multi-component analysis of FTIR spectra of non-linear system using polynomial partial least squares method].

A non-linear algorithm, polynomial PLS was applied to the simultaneous analysis of OP-FTIR spectra of a five-component system whose FTIR spectra were seriously overlapped. The results were compared with the one obtained from PLS. PPLS yielded good performance, especially for the prediction of benzene and chloroform. RMSEP (root mean squared error of prediction) of benzene and chloroform in PPLS model were 0.043 and 0.087 and the corresponding values in PLS were 0.402 and 0.842, respectively. Meanwhile, variance was accounted by PPLS with fewer latent variables, which indicates the simplicity and robustness of the model. The successful application of PPLS to non-linear system was meaningful for the use of remote sensing FTIR in air monitoring.

English Abstract↗
PubMed2006

[Interleukin-6-597G/A and -572C/G polymorphisms and risk of coronary heart disease].

OBJECTIVE: To explore the relationship between interleukin-6 (IL-6) gene polymorphisms and the risk of coronary heart disease (CHD). METHODS: IL-6/-597G/A and -572C/G polymorphisms were genotyped in 245 CHD patients and 260 healthy adults by PCR-RFLP. Serum IL-6 level was examined by ELISA. Logistic regression was performed to observe the relationship between IL-6/-572C/G polymorphism and other risk factors of CHD. RESULTS: IL-6/-597G/A genotype was similar between the two groups. The frequencies of IL-6/-572C/G genotype and G allele were more frequent in patients with CHD than that in controls (P < 0.01). Compared with CC genotype, the relative risk for CHD in people with CG and GG genotypes was 1.46 (95% CI: 1.01 - 2.10, P < 0.05) and 5.19 (95% CI: 1.69 - 15.89, P < 0.01), respectively. The serum levels of IL-6 were similar between carriers of the IL-6/-572G allele and patients with CC genotype (P > 0.05). IL-6/-572 C/G is related to total cholesterol (OR 1.76, 95% CI: 1.05 - 3.16, P < 0.05) and triglyceride (OR = 2.51, 95% CI: 1.04 - 6.45, P < 0.05), respectively. CONCLUSION: IL-6/-597G/A polymorphism was not associated with susceptibility to CHD, but IL-6-572C/G polymorphism may be a possible genetic susceptibility factor for CHD in Chinese Hans population.

Adult↗
PubMed2006

[Comprehensive study of lead pollution in atmospheric aerosol of Shanghai].

The lead contamination, lead species and source assignment were studied by a combination of several analytical techniques such as Proton-induced X-ray emission analysis (PIXE), Proton microprobe (micro-PIXE), Inductively coupled plasma-mass spectrometry (ICP-MS) and extended X-ray absorption fine structure (EXAFS) techniques. The results indicate that the lead concentration in the air of Shanghai gradually decreased over the last years. The atmospheric lead concentration of PM10 in the winter of 2002 was 369 ng x m(-3), which had declined by 28% in 2001, and in the winter of 2003 it decreased further to 237 ng x m(-3). The main lead species in the samples collected in the winter of 2003 were probably PbCl2, PbSO4 and PbO. The source apportionment was calculated in terms of the combination of lead isotope ratios and lead mass balance method, assisted by single particle analysis with micro-PIXE and pattern recognition. The results suggest that the major contributors of atmospheric lead pollution in Shanghai are the coal combustion dust; the metallurgic dust and vehicle exhaust particles, with a contribution around 50%, 35% and 15%, respectively. It probably is the first time to give a city a quantitative estimation of lead pollution contribution from emission sources. The influence from leaded gasoline was still present in the atmosphere by four or five years after the phasing out of leaded gasoline.

Aerosols↗
PubMed2006

[Suppression of telomerase activity by plasmid-mediated RNA interference].

This study was aimed to construct a plasmid expressing siRNA specific for the human telomerase reverse transcriptase (hTERT) gene and to evaluate the ability of small interference RNA(siRNA) for inhibiting telomerase activity in HeLa cells. 64 nucleotides, in which 19 nt were homologous with hTERT gene, were chemically synthesized, annealed and linked into pSUPER to get pSUP-hTE. Then pSUP-hTE was digested with enzyme. We obtained its fragmant concluding promoter and 64nt. So we cloned it into pEGFP-C1 for constructing pEGFP-hTE which contains neo gene and the enhanced green fluorescent protein (EGFP). Recombinant pEGFP-hTE was transfected to HeLa cells. These cells were screened with medium containing G418. When stable colonies appeared, G418-resistant cells were harvested and propagated. At the different cell generations, hTERT mRNA and protein expression, telomerase activity and cell growth activity were analyzed. Compared with control cells, HeLa cells transfected with pEGFP-hTE showed that hTERT mRNA level and hTERT protein expression decreased and telomerase activity reduced by 38%, but the cells growth activity displayed no changes. So pEGFP-hTE could specifically inhibit expression of hTERT and telomerase activity. These results suggested that siRNA targeting hTERT gene might provide a new strategy for cancer biotherapy.

Base Sequence↗
PubMed2006

[Construction of recombinant Mycobacterium smegmatis expressing ESAT-6 and its effects on macrophages].

OBJECTIVE: Objective To construct recombinant Mycobacterium smegmatis expressing ESAT-6 of the human pathogen Mycobacterium tuberculosis. METHODS: ESAT-6 gene was amplified from M. tuberculosis genomic DNA and inserted into an E.coli-mycobacterium shuttle vector under the control of HSP60 promoter. The recombinant vector was transformed into M. smegmatis by electroporation. To assess the ability of recombinant M. smegmatis to activate macrophage, mouse macrophage ANA-1 was cocultured with recombinant M. smegmatis. The apoptosis of ANA-1 cells was detected by flow cytometry and iNOS mRNA expression of the cells was detected by reverse transcription-polymerase chain reaction (RT-PCR). The survival of M. smegmatis strains in ANA-1 cells was evaluated. RESULTS: The recombinant vector was verified by restriction endonuclease digestion and DNA sequencing. ESAT-6 protein was expressed in M. smegmatis in response to heat shock and the molecular weight of the expression product was identical to the expected value. The growth curve of the new recombinant M. smegmatis was consistent with that of the wild-type strain, suggesting the absence of ESAT-6 protein toxicity against M. smegmatis. The recombinant M. smegmatis did not induce significant changes in mouse macrophage ANA-1 apoptosis. Coculture of the macrophages with recombinant M. smegmatis for 4 to 24 h could induce iNOS expression in the former, and the CFU of recombination M. smegmatis grown in ANA-1 cells was much less than that of the control bacteria. CONCLUSION: The recombinant M. smegmatis expressing M. tuberculosis ESAT-6 gene possess immunogenicity, which provides experimental evidence for the development of novel M. smegmatis-based vaccine against tuberculosis.

Animals↗
PubMed2006

[Study on the relationship between polymorphisms of genes (CYP17, CYP19 and SULT1A1) and susceptibility to breast cancer in Chinese women].

OBJECTIVE: To investigate the relationship between polymorphisms of genes (CYP17, CYP19 and SULT1A1) involved in estrogen metabolism and susceptibility to breast cancer in Chinese women. METHODS: A case-control study was performed. PCR-base restriction fragment length polymorphism (PCR-RFLP) and short tandem repeat polymorphism (STRP) assays were used to detect the polymorphism distribution of CYP17, CYP19 and SULT1A1 in 213 breast cancer cases and 430 matched controls. Logistic regression analyses were used to determine the OR, multivariate adjusted OR and 95% CI of each and all three genes and estrogen exposure factors on the risk of breast cancer. Relationship between polymorphisms and clinic-pathological features was also assessed. RESULTS: The frequency of A2 allele of CYP17 was 49.8% in cases and 49.1% in controls (P > 0.05). The frequency His allele of SULT1A1 in cases (13.6%) was significant higher than that of controls (9.5%) (P = 0.03). There was also significant difference in the frequencies of (TTTA)10 allele CYP19 which was 12.4% in cases and 8.2% in controls (P = 0.02). Multigenic model indicated that there was an increased risk of breast cancer with more numbers of high-risk genotypes in a dose-response effect (trend P = 0.05). Data from multivariate analysis showed that the allele of SULT1A1 His and CYP19 (TTTA)10 was positively associated with the risk of breast cancer. Other well-established risk factors as higher estrogen exposure including total years of menstrual, early menarche etc, and women with a higher BMI and WHR were all served as independent risks. CONCLUSION: This study indicated that the polymorphisms of estrogen-metabolizing genes were related to breast cancer.

Aromatase↗