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Biomedical subjects

Li Chen

Publications and source records attributed to Li Chen.

At least 163 records · Page 9Linked to original sources
PubMed2005

[Effects of dexamethasone on arsenic trioxide induced apoptosis, NF-kappaB activation and gene expression in lymphoma cell line].

OBJECTIVES: To study the effect of dexamethasone (Dex) on the apoptosis and NF-kappaB activation in Raji cells as well as expression of MMP9 and VEGF induced by As2O3, and to observe the effect of inhibited activity of NF-kappaB by Dex on apoptosis. METHODS: Cell apoptosis was analysed by Annexin V. Fluctuation of NF-kappaB, MMP9 and VEGF was detected by semi-quantitative immunohistochemistry. RESULTS: The apoptosis and activation of NF-kappaB of Raji cells could be induced by As2O3. The percentage of apoptosis was (39.2 +/- 1.3)%. Dex significantly increased (77.5%) the apoptosis induced by As2O3 (P < 0.05). Dex suppressed the activation of NF-kappaB induced by As2O3 (a suppression rate of 28.0%, P < 0.05). There was a positive correlation between the changes of MMP9, VEGF and NF-kappaB. CONCLUSIONS: As2O3 could induce apoptosis, activate NF-kappaB and up-regulate expression of MMP9 and VEGF of Raji cells. The mechanism of enhanced apoptosis by Dex may be related to suppressing activation of NF-kappaB and down-regulating expression of MMP9 and VEGF.

Apoptosis↗
PubMed2005

[Spectrum of gene expression of a multi-drug resistant leukemia cell line with high tumorigenicity in nude mice].

OBJECTIVE: To investigate the mechanism of multi-drug resistance of K562-n/VCR cell line with both bcr-abl and mdr-1 expressions by clustering analysis of differential gene expression profiles. METHODS: By DNA microarray technique, genes differentially expressed by K562-n/VCR and K562-n cell lines were identified and analyzed. RESULTS: DNA microarray analysis of K562-n/VCR and K562-n cells was repeated three times and revealed 58 genes significantly differentially expressed among 12,800 genes arrayed. All but one was up-regulated in K562-n/VCR cells. The only gene down-regulated was a-myb. The up-regulated genes were MDR-associated genes, oncogenes, cytoskeleton, protein kinases and phosphatases, apoptotic and antiapoptotic factors, metabolism, transcriptional regulators associated with stress response, cell cycle checkpoint control, and genes for signal transduction proteins. CONCLUSION: These results indicate that, besides MDR-associated genes, other known and unknown genes may also be involved in the mechanism of multi-drug resistance.

Animals↗
PubMed2005

[Study on the relationship between methylene tetrahydrofolate reductase gene (677C-->T) mutation and skin lesions in endemic arsenic poisoning].

OBJECTIVE: Methylene tetrahydrofolate reductase (MTHFR) is the key enzyme in folate metabolism. We examined whether single nucleotide 677 C-->T mutation in the MTHFR gene could affect the occurrence of skin lesions in endemic arsenic poisoning. METHODS: Fifty individuals with arsenic-induced skin lesions were identified as cases, and 35 individuals without skin lesions from the same village were selected as controls. The MTHFR C677T polymorphism was analyzed by PCR-RFLP method, serum folic acid and Vitamin B12 were determined by microbiological assay and the electrochemiluminescence immunoassay, respectively. RESULTS: The frequencies of TT genotype and T allele in case group were 34.0% and 56.0%, respectively, and were not significantly different from those in controls. There was no significant difference between case and control group in the levels of folic acid and Vitamin B12 in serum. Compared to subjects carrying the CC genotype and having the level of folic acid above 10.5 nmol/L, other subjects were at elevated risk of skin lesions, but the 95% CI of both crude OR and adjusted OR (controlled for age, gender, smoking and arsenic level in drinking water) include 1. CONCLUSION: This study did not find the relationship between MTHFR gene (677C-->T) mutation and skin lesions in endemic arsenic poisoning.

Adult↗
PubMed2005

Linkage disequilibrium and haplotype analysis of two single nucleotide polymorphisms in STK15 in Chinese.

STK15 (Serine/Threonine protein kinase 15) is a serine/threonine kinase encoding gene, whose overexpression in mammalian cells leads to centrosome amplification, chromosomal instability, and oncogenic transformation. 91A-->T, a single nucleotide polymorphism (SNP) in exon 3 of STK15, has recently been shown to be associated with human cancer susceptibility. Within exon 3 of STK15, there are three nonsynonymous SNPs: 91 A-->T, 169G-->A and 311C-->T. We have determined STK15 genotypes and haplotypes composed of 91A-->T and 169G-->A by PCR-RFLP in a randomly sampled cohort of 193 normal individuals from Northeast China. DNA samples from all individuals were subjected to first round of PCR using a pair of specific primers. For the subsequent nested PCR,a mismatch forward primer, which could introduce an EcoR I restriction site to the 91A allele, was included. The nested PCR products were digested with the restriction endonucleases EcoRI and AccII. The double restriction digests were separated by polyacrylamide gel electrophoresis. Three haplotypes,91A-169G, 91T-169A and 91T-169G, were detected and their frequencies were 68.65%, 10.88% and 20.47%, respectively. Six genotypes composed of the above three haplotypes were found,and their frequencies were 91A-169G/91 A-169G (46.11%), 91A-169G/91 T-169A (14.51%), 91A-169G/91T-169G (30.57%), 91T-169G/91T-169G (3.11%), 91T-169G/91T-169A (4.15%), 91T-169A/91T-169A (1.55%). Whereas no 91A-169A haplotype was detected in all individuals examined in the current study, linkage disequilibrium (LD) between the two SNPs was found.

Alleles↗
PubMed2005

[Cloning of CTB-PROIN fusion gene and its expression in Escherichia coli].

A fusion gene CTB-PROIN, in which Proinsulin gene was fused to the 3' end of CTB gene by a hinge peptide 'GPGP', was constructed and cloned into pET-30a(+) to obtain a prokaryotic expression vector pETCPI. Subsequently the recombinant plasmid pETCPI was transformed into E. coli stain BL21 (DE3). After induced by IPTG, the expression product was analyzed by sodium dodecyl sulphate-polyacrylamide gel (15%) electrophoresis (SDS-PAGE), and its result indicated that the recombinant protein CTB-PROIN was expressed and accumulated as inclusion bodies. The recombinant CTB-PROIN protein accumulated to the level of 25% of total bacterial proteins. After inclusion bodies was denaturalized and refolded in vitro, significant assembly of monomers had occurred, and the recombinant protein represented assembled pentamers. The results of western blotting analysis also demonstrated that the fusion protein could be recognized by the anti-CT and anti-insulin antibody, respectively. In addition, the result of the CTB-PROIN-GM1 binding assay, that the protein could bind to monosialoganglioside specifically, showed it possesed biological activity in vitro. These results provided the possibility of developing a cheaper and more efficient oral vaccine for type I diabetes using such constructs.

Artificial Gene Fusion↗
PubMed2005

[Protective effect of tetramethylpyrazine on the respiratory inhibition induced by hypoxia in rats].

OBJECTIVE: To study the protective effect of tetramethylpyrazine (TMP) on the respiratory inhibition induced by hypoxia. METHODS: Forty-four SD rats were used. The hypoxic rat model was established. The effects of TMP on the responses of respiratory activity and life time to hypoxia were observed. The Nissl's staining and immunohistochemical technique were used to investigate the effect of hypoxia on the Nissl's bodies and FOS expression in the brainstem and the antagonistic action of TMP. RESULTS: In contrast to the group of hypoxia, the occurrence of respiratory inhibition was delayed and the life time was prolonged obviously in the rats of hypoxia plus TMP (P<0.01). Compared with the air contronl group, the intensity of the Nissl's staining of the brainstem neurons became weaker in the group of hypoxia, but in the group of hypoxia plus TMP, the Nissl's staining was stronger and the gray degree decreased obviously, compared with the group of hypoxia (P<0.05). FOS positive neurons were induced by hypoxia and mainly existed in the nucleus of solitary tract, area postrema, hypoglossal nucleus, lateral reticular nucleus, inferior olivary nucleus, nucleus raphe pallidus, facial nucleus, trapezoid nucleus, but in the group of hypoxia plus TMP, the level of FOS immunoreactivity decreased remarkably, compared with the group of hypoxia (P<0.05). CONCLUSION: TMP has protective effect on the respiratory inhibition induced by hypoxia and FOS may be involved in the protection.

Animals↗
PubMed2005

Preparation and analysis of cSNP chip on hepatocellular carcinoma-related genes.

BACKGROUND: The understanding of cSNPs of cancer-related genes harboring in high frequency loss regions of tumor chromosomes can advance the disclosure of genetic and variant mechanisms of tumorigenesis, and the investigation of cancer susceptibility. In preparing a gene chip for detecting polymorphisms on coding region of genes in hepatocellular carcinoma tissues, some cSNPs are of interest for their potential links with phenotype. METHODS: The genes harboring in loss regions with high frequency of hepatocellular carcinoma (HCC) were selected, the related information of cSNP sequences was obtained from the SNP database (dbSNP) of the National Center for Biotechnology Information (NCBI). Then appropriate primers and oligonucleotide probes were designed according to the SNP sites, and a gene chip for the detection of SNPs was constructed. The chip included 48 cSNPs of 25 hepatocellular carcinoma-related genes. The PCR products labeled by Dig-dUTP were hybridized with the cSNP chip. RESULTS: The sensitivity, influence by probe concentration, and reiteration of the chip were detected, with a high sensitivity of 6X10(-3) ng/mul. The signal of hybridization was reduced with a lower concentration of probe. Seven polymorphisms of caspase 9 (rs2308941)C-->T and DOK2(rs2242241) T-->G, 6 of polymorphisms of EGFL3 (rs947345)A -->G, caspase 9 ( rs2308938) C-->G and PHGDH(rs1801955)T-->A, 5 of polymorphisms of E2F2(rs3218170) G-->A,4 of polymorphisms of MUTYH(rs1140507)T-->C and BNIP3L(rs1055806)G-->T, and 1 of polymorphism of TNFRSF1B (rs1061622)T-->G were detected by the chip in the tissues of 10 HCC. Samples of caspase 9 (rs2308941G) and (rs2308941A) were verified by PCR-SSCP and sequencing. CONCLUSION: The cSNP chip of hepatocellular carcinoma-related genes can accelerate the discovery of polymorphic markers on hepatocellular carcinoma.

Adult↗
PubMed2005

[Study of high-risk factors of surgical site infection after cesarean section].

OBJECTIVE: To study the high-risk factors of surgical site infection after cesarean section. METHODS: We retrospectively reviewed cesarean section cases with surgical site infection and evaluated the high-risk factors related to the infection. RESULTS AND CONCLUSIONS: Totally 14 factors were identified as the high-risk factors such as obesity, inadequate antibiotic prophylaxis, low ferrohemoglobin level, existing infection before hospitalization, multiple vaginal and anal examinations, premature rupture of membranes, and prolonged operative time. The 7 factors such as emergency operation were not shown to be significant high-risk factors. The probability of parturient with frequently vaginal examination to acquire infection following cesarean section was 75.2%, which was judged by classification analysis. A stepwise addition of the factors for analysis showed some difference in the predicted probability, which was 75.2% for inadequate antibiotic prophylaxis, 82.4% for low ferrohemoglobin level, 81.7% for prolonged operative time, 86.3% for obesity, 83.7% for premature rupture of the membranes, and 84.9% for existing infection before hospitalization.

Cesarean Section↗
PubMed2005

[cDNA microarray to identify the significance of DNA replication and damage repair genes associated with benzene poisoning].

OBJECTIVE: To screen DNA replication, and damage repair genes associated with benzene poisoning by using gene expression profile analysis. METHODS: Leucocytes in peripheral blood of seven patients and seven normal controls were collected and total RNA was extracted. The cDNA probes were prepared by labeling cell RNA with Cy3-dUTP and Cy5-dUTP with reverse transcription. The arrays with 141 genes were hybridized against the cDNA probe mixture, and the fluorescent signals were scanned. RESULTS: Twenty five differentially expressed genes were screened out. Among these genes, 16 genes were up-regulated and 9 down-regulated. They were DNA replication genes such as PRIM2A, ORC1L etc; DNA synthesis, recombination and repair genes such as POLK etc; DNA damage signaling/repair proteins and DNA ligases such as RECQL, PRKDC, G22P1, ERCC3, ERCC1, CRY1, CHES1, BRCA2, APEX etc; proteins involved in recombination such as RECQL; and other DNA synthesis, recombination, and repair proteins such as SKIV2L, RBMS1, SON, SET. CONCLUSIONS: Some DNA replication, and damage repair genes associated with benzene poisoning show differential expression, which provides the basis for screening biomarkers of benzene poisoning.

Benzene↗
PubMed2005

[The reverse buccinator musculomucosal flap for the treatment of inverted papilloma of the nose].

OBJECTIVE: This paper presents the experience in using the reverse buccinator musculomucosal flap for repairing the defect following excising inverted papilloma of the nose. METHODS: After the inverted papilloma of the nose was excised through an endonasal approach, the reverse buccinator musculomucosal flap supplied by the retrograde blood flow of the anterior buccal artery was harvested and sutured to the defect through the ora-nasal tunnel. The procedure was performed on three patients. RESULTS: The postoperative course was uneventful. All the flaps survived completely. CONCLUSIONS: The technique provides the solution to prevent nasal stricture from cicatricial contracture after excising inverted papilloma. In the operation, excising the inverted papilloma and repairing the defect was performed simultaneously, saving another operation for the secondary deformity. The technique is also applicable to the treatment of existing cicatricial stricture of the nose.

Humans↗
PubMed2005

[Soft-ridged bench terrace design in hilly loess region].

Reconfiguration of hillside field into terrace is regarded as one of the key techniques for water and soil conservation in mountainous regions. On slopes exceeding 30 degrees, the traditional techniques of terracing are difficult to apply as risers (i.e., backslopes), and if not reinforced, are so abrupt and easy to collapse under gravity alone, thus damaging the terrace. To improve the reconfiguration of hillside field into terrace, holistic techniques of soft-ridged bench terrace engineering, including revegetation, with trees and planting grasses on riser slopes, were tested between 1997 and 2001 in Xiabiangou watershed of Yan' an, Shaanxi Province. A "working with Nature" engineering approach, riser slopes of 45 degrees, similar to the pre-existing slope of 35 degrees, was employed to radically reduce gravity-erosion. Based on the concepts of biodiversity and the principles of landscape ecology, terrace benches, bunds, and risers were planted with trees, shrubs, forage grasses, and crops, serving to generate a diverse array of plants, a semi-forested area, and to stabilize terrace bunds. Soft-ridged bench terrace made it possible to significantly reduce hazards arising from gravity erosion, and reduce the costs of individual bench construction and maintenance by 24.9% and 55.5% of the costs under traditional techniques, respectively. Such a construction allowed an enrichment and concentration of nutrients in the soils of terrace bunds, providing an ideal environment for a range of plants to grow and develop. The terrace riser could be planted with drought-resistant plants ranging from forage grasses to trees, and this riser vegetation would turn the exposed bunds and risers existing under traditional techniques into plant-covered belts, great green ribbons decorating farmland and contributing to the enhancement of the landscape biology.

Agriculture↗
PubMed2005

The expression of CD97EGF and its ligand CD55 on marginal epithelium is related to higher stage and depth of tumor invasion of gastric carcinomas.

CD97EGF is a member of the EGF-TM7 family of class II seven-transmembrane (7TM), and its cellular ligand CD55 (also known as decay accelerating factor; DAF) protects host cells from complement attack. To determine whether the expression levels of these two molecules are correlated with the clinicopathological features of gastric carcinomas, a total of 35 gastric carcinomas and their corresponding margins and normal specimens were investigated by RT-PCR, Western blot analysis and immunohistochemistry. Transcript levels of CD97EGFand CD55 were higher in tumors than those in the margin and normal epithelial mucous tissues (P<0.05). However, the expression levels of CD97EGF and CD55 mRNA had no correlation with the clinicopathological features of gastric carcinoma patients. All three groups of specimens were immunoreactive for CD97EGF and the CD55 protein. Strong and specific immunoreactivities of CD97EGF were located in the mucosal epithelia of the marginal basal membrane. Expression of CD97(EGF) in the margins showed a marked difference between the depth of tumor invasion T1 and T2, 3 and 4, and stages I and II/III/IV of gastric carcinomas (P<0.05). The expression of CD55 protein was highly correlated with CD97EGF (R=0.6483, P<0.001). Western blot analysis confirmed the expression and distribution patterns of CD97EGF and CD55. Our findings suggest that CD97EGF may play a role in the development and invasion of gastric carcinomas by binding its cellular ligand CD55. Detection of the CD97EGF expression in the tumor margin could be referred to as the molecular edge of gastric carcinomas.

Antigens, CD↗
PubMed2005

[Arsenic trioxide induced leukemic cell apoptosis relative to NF-kappaB activation].

To investigate the relationship of As(2)O(3)-induced leukemic cell apoptosis with NF-kappaB activation and expression of VEGF, MMP9, apoptosis of K562-n cells induced by As(2)O(3) was analyzed by Annexin V, the dynamic changes of NF-kappaB, MMP9 and VEGF expressions were detected by immunohistochemistry. The results showed that activity of NF-kappaB could be increased, accompanied by higher level of expression of MMP9 and VEGF when apoptosis of K562-n cells was induced by As(2)O(3). Dexamethasome not only increased significantly the apoptotic rate, but also suppressed the activation of NF-kappaB of K562-n cells induced by As(2)O(3). Furthermore, there was a positive correlation between the expression of MMP9, VEGF and the activity of NF-kappaB. It is concluded that As(2)O(3) can induce apoptosis, in the meanwhile, activate NF-kappaB and up-regulate expression of MMP9 and VEGF in K562-n cell line. The mechanism of apoptosis of K562-n cells enhanced by dexamethasome may be related to suppression of the activation of NF-kappaB and expression of MMP9 and VEGF.

Antineoplastic Agents↗
PubMed2005

[Controlled study on acupoint group prescriptions for electroacupuncture treatment of insomnia].

OBJECTIVE: To probe into the best acupoint group prescription for electroacupuncture treatment of insomnia. METHODS: Sixty-six cases were randomly divided into 3 groups. In the group I Sishencong (EX-HN 1) and Fengchi (GB 20) were selected, in the group II, Baihui (GV 20) and left Shenmen (HT 7), in the group III. Yin-tang (EX-HN 3) and Shenting (GV 24). Their therapeutic courses and therapeutic effects were compared. RESULTS: The effective rate was respectively 72.73%, 77.27% and 95.45% in the 3 groups, the group III being significantly better than the group I and the group II (P < 0.01), but there was no significant difference between the group I and the group II (P > 0.05). CONCLUSION: Electroacupuncture at Yintang (EX-HN 3) and Shenting (GV 24) has obvious therapeutic effect on insomnia.

Acupuncture Points↗
PubMed2005

[Recipient lymphopenia state enhances the expansion and anti-leukemia effect of leukemia specific cytotoxic T lymphocytes].

OBJECTIVE: To determine the role of recipient lymphopenia state in the expansion and function of leukemia specific cytotoxic T lymphocytes (CTLs). METHODS: C57BL/6 mice were induced to lymphopenia with 6 Gy total body irradiation. Spleen T cells or leukemia specific T cells from EGFP+ transgenic C57BL/6-EGFP mice were adoptively transferred by intravenous injection. The mice were challenged subcutaneously with 1 x 10(6) FBL3 leukemic cells at day 2 after irradiation. The peripheral WBC count, percentage of EGFP+ cells, subsets of T cells and tumor sizes were monitored. RESULT: Both of the spleen T cell and leukemia specific CTL proliferated efficiently with the percentage of EGFP+ cells of 28. 81% and 42.24%, respectively, after infused into lymphopenic recipients. However, spleen T cells had no anti-leukemia effect regardless of its expansion. In contrast, leukemia specific CTLs showed a more rapid and extensive expansion under the condition of lymphopenia and a enhanced anti-leukemia immunity. CONCLUSION: Transfusion of leukemia specific CTLs under lymphopenia state could be a feasible strategy to expand leukemia specific CTLs and generate favorable anti-leukemia effect in vivo.

Animals↗
PubMed2005

[Study on the prevalence of low reproductive tract infection diseases and related risk factors among married women of bearing-age in rural area of Shandong province].

OBJECTIVE: To study the prevalence of child-bearing age women with reproductive tract infection (RTI) and related risk factors in the rural area of Shandong so as to develop measurements on prevention. METHODS: Four communities were randomly selected based on economic levels and a baseline investigation on RTI was carried out. RESULTS: A total prevalence rate of RTI was 47.57% with breakdown for four communities-Zhucheng, Zhangqiu, Daiyue and Wudi as 53.91%, 41.49%, 48.37%, 44.88% respectively. Nearly 60% of women at child-bearing age were ignorant on sexually transmitted diseases (STD). Risk factors of RTI would include incorrect perineum cleanout, bad habit of sexual intercourse and low education level of the husbands. CONCLUSION: High prevalence of RTI was associated with low level of education, lack of awareness on STD related hygiene and low rate of seeing doctor for RTI disorder in those women. The results of this study would benefit to the development of intervention measurement of RTI.

Adult↗
PubMed2005

[Establishment of a mouse model for detecting multi-drug resistant minimal residual leukemia cells expressing green fluorescent protein].

This study aimed to investigate the pathophysiology and therapy of multi-drug resistant model of minimal residual leukemia in mice. The multi-drug resistant model of minimal residual leukemia was established by using P388/VCR-G cell line expressing enhanced green fluorescent protein (EGFP) and DBA mice. The results showed that P388/VCR-G were inoculated in the abdominal cavities of DBA mice, the incidence of leukemia was 100%. Any of these mice with leukemia could not obtain remission spontaneously. The model of leukemia was sensitive to cyclophosphamide (Cy) and the time of survival was related to the dose of Cy received. The logarithm of cells inoculated in mice correlated regressionally with the dose of Cy. So this model was ideal for research on minimal residual leukemia. The distribution of residual leukemia cells in complete remission was not uniform in different organs including liver, spleen, thymus and bone marrow. Minimal residual leukemia cells could be found by fluorescent microscopy in freezing tissue slice. It is concluded that the multi-drug resistant model of minimal residual leukemia expressing EGFP can be established by using P388/VCR-G cell line and DBA mice. The minimal residual leukemia cells can be observed by fluorescence microscopy in complete remission stage.

Animals↗