Biomedical subjects

Qi Li

Publications and source records attributed to Qi Li.

At least 127 records · Page 7Linked to original sources

PubMed2003

Preparation and characterization of a set of monoclonal antibodies to TRAIL and TRAIL receptors DR4, DR5, DcR1, and DcR2.

The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL/Apo 2L) is a novel cytotoxic ligand belonging to TNF superfamily. Among TRAIL receptors, death receptor 4 (DR4) and DR5 containing death domain (DD) in their cytoplasmic region mediate apoptosis-signaling upon TRAIL binding, while decoy receptor 1 (DcR1) and DcR2 with a truncated or non-functional DD play "decoy" role. The interaction of TRAIL and TRAIL receptors plays important roles both in immunoregulation and immune pathogenesis of some diseases. In this study, we raised hybridomas secreting monoclonal antibodies against TRAIL (FMU1.1, 1.2, 1.3), DR4 (FMU1.4), DR5 (FMU1.5, 1.6), DcR1 (FMU1.7) and DcR2 (FMU1.8, 1.9). These MAbs could be used for fluorescent staining and flow cytometry (FCM) analysis as well as immunohistochemistry (IHC). Moreover, FMU1.1, 1.3, 1.4 and 1.5 could be used as coating antibodies paring corresponding polyclonal antibodies to develop sandwich ELISAs to quantitate the soluble TRAIL (sTRAIL), sDR4 or sDR5 in serum samples respectively. In addition, cross-linking of DR4/DR5 by FMU1.4 or FMU1.5 MAbs could induce apoptosis of some DR4/DR5-expressing tumor cells. Thus, this set of monoclonal antibodies against TRAIL or TRAIL receptors may be useful in expression phenotypic and functional study of TRAIL and TRAIL receptors.

Animals↗

PubMed2003

Soy food consumption is associated with lower risk of coronary heart disease in Chinese women.

Soy food intake has been shown to have beneficial effects on cardiovascular disease risk factors. Data directly linking soy food intake to clinical outcomes of cardiovascular disease, however, are sparse. We examined the relationship between soy food intake and incidence of coronary heart disease (CHD) among participants in the Shanghai Women's Health Study, a population-based prospective cohort study of approximately 75000 Chinese women aged 40-70 y at the baseline survey that was conducted from 1997 to 2000. Included in this study were 64915 women without previously diagnosed CHD, stroke, cancer and diabetes at baseline. Information on usual intake of soy foods was obtained at baseline through an in-person interview using a validated food-frequency questionnaire. Cohort members were followed biennially through in-person interviews. After a mean of 2.5 y (162277 person-years) of follow-up, 62 incident cases of CHD (43 nonfatal myocardial infarctions and 19 CHD deaths) were documented. There was a clear monotonic dose-response relationship between soy food intake and risk of total CHD (P for trend = 0.003) with an adjusted relative risk (RR) of 0.25 (95% CI, 0.10-0.63) observed for women in the highest vs. the lowest quartile of total soy protein intake. The inverse association was more pronounced for nonfatal myocardial infarction (RR = 0.14; 95% CI, 0.04-0.48 for the highest vs. the lowest quartile of intake; P for trend = 0.001). This study provides, for the first time, direct evidence that soy food consumption may reduce the risk of CHD in women.

Adult↗

PubMed2003

Identification of the essential histidine residue for high-affinity binding of AlbA protein to albicidin antibiotics.

The albA gene from Klebsiella oxytoca encodes a protein that binds albicidin phytotoxins and antibiotics with high affinity. Previously, it has been shown that shifting pH from 6 to 4 reduces binding activity of AlbA by about 30%, indicating that histidine residues might be involved in substrate binding. In this study, molecular analysis of the albA coding region revealed sequence discrepancies with the albA sequence reported previously, which were probably due to sequencing errors. The albA gene was subsequently cloned from K. oxytoca ATCC 13182(T) to establish the revised sequence. Biochemical and molecular approaches were used to determine the functional role of four histidine residues (His(78), His(125), His(141) and His(189)) in the corrected sequence for AlbA. Treatment of AlbA with diethyl pyrocarbonate (DEPC), a histidine-specific alkylating reagent, reduced binding activity by about 95 %. DEPC treatment increased absorbance at 240-244 nm by an amount indicating conversion to N-carbethoxyhistidine of a single histidine residue per AlbA molecule. Pretreatment with albicidin protected AlbA against modification by DEPC, with a 1 : 1 molar ratio of albicidin to the protected histidine residues. Based on protein secondary structure and amino acid surface probability indices, it is predicted that His(125) might be the residue required for albicidin binding. Mutation of His(125) to either alanine or leucine resulted in about 32 % loss of binding activity, and deletion of His(125) totally abolished binding activity. Mutation of His(125) to arginine and tyrosine had no effect. These results indicate that His(125) plays a key role either in an electrostatic interaction between AlbA and albicidin or in the conformational dynamics of the albicidin-binding site.

Anti-Bacterial Agents↗

PubMed2003

[Fibrillin-1 gene mutation in Chinese patients with Marfan syndrome and its gene diagnosis by haplotype analysis].

OBJECTIVE: To analyze fibrillin-1 (FBN(1)) gene mutation in Chinese patients with Marfan syndrome(MFS) and to make a gene diagnosis by haplotype analysis for MFS. METHODS: Nine MFS families were analysed with single strand conformation polymorphism(SSCP) and DNA sequencing. With the use of four primers designed in the flanking sequences of each short-sequence tandem-repeat region in FBN(1) gene, the haplotype-segregation analysis for MFS(B) was performed. RESULTS: In MFS(A)II(1), PCR-SSCP detected SSCP band alterations in exon 25 of FBN(1) gene; direct sequencing showed a small 13bp deletion, the deleted sequence being gcctctgcaccca at base 3243-3456 of cDNA. This mutation caused a frame-shift which was never seen in any unaffected members of the family, and it was a heterozygous mutation; neither of them was identified in 100 chromosomes from 50 normal control individuals. Haplotype-segregation analysis suggested that the disease was passed from Subject I(2) to Subject II(2), Subject II(3), Subject II(5) with the same allele in MFS B family, the proband's daughter also inherited the allele. These data indicated that MFS(B) family was linked to FBN(1) gene, the proband's daughter was an asymptomatic patient. CONCLUSION: The combination of mutation analysis and haplotype analysis can provide more evidence for gene diagnosis.

Base Sequence↗

PubMed2003

[Generation of high affinity humanized single-chain antibody against PreS1 of hepatitis B virus from immune phage displayed antibody library].

OBJECTIVE: Screening and characterizing high affinity completely humanized single-chain antibody (ScFv) against PreS1 of hepatitis B virus. METHODS: A combinatorial library of phage-displayed human ScFv, genes of which were derived from peripheral blood lymphocytes immunized by PreS1 of Hepatitis B Virus in vitro, was constructed. The library contained 7 10(8) clones. RESULTS: After 3 rounds panning, a high affinity (K=10(7) to 10(8) mol/L) ScFv specific to PreS1 was obtained. The V(H) belonged to human V(H4) family, and V(1) to V(4) by sequence analysis. CONCLUSION: This study suggests that the method of antigen stimulation in vitro is an expeditious way for the source of human immune antibody. And the ScFv may provide a more satisfactory therapy.

Antibodies, Monoclonal↗

PubMed2003

[Mutation analysis of neurofilament-light gene in Chinese Charcot-Marie-Tooth disease].

OBJECTIVE: To study the characteristic of the mutation of neurofilament-light (NF-L) gene in Chinese Charcot-Marie-Tooth disease (CMT) patients. METHODS: Mutation analysis of NF-L gene was made by use of polymerase chain reaction-single strand conformation polymorphsim combined with DNA direct sequencing in 32 CMT probands from the Hans of five provinces in China who had been diagnosed by clinical feature and electromyography and/or biopsy of sural nerve. RESULTS: In 32 CMT probands, only one sporadic case was found to display variant banding pattern, and this case was confirmed as 1329C to T (Tyr443Tyr) single nucleotide polymorphism by sequencing. CONCLUSION: Mutation of NF-L gene may be rare in Chinese CMT patients.

Adolescent↗

PubMed2003

[Expression of matrix metalloproteinase-2 in hypopharyngeal carcinoma and its clinical significance].

OBJECTIVE: To study the relationship between matrix metalloproteinase-2(MMP-2) and the biological behavior, metastasis and prognosis of hypopharyngeal carcinoma. METHODS: Two-step immunohistochemical method was used to examine the expression of MMP-2 mAb in 32 specimens of hypopharyngeal carcinoma tissues and adjacent normal mucosa. Statistical comparison was performed after grouping. RESULTS: It was found that the positivity rate for MMP-2 in the hypopharyngeal carcinoma tissues was 53.1%(17/32). Significant differences were noted when the expression levels of the mAb were compared between the normal mucosa adjacent to the carcinomas and the carcinomatous tissue, and between non-metastatic carcinomas and those with cervical lymph node metastasis. Patients with a positive result had obviously lower 3-year survival rate than those with negative results. CONCLUSION: MMP-2 may play a role in the lymph node metastasis of hypopharyngeal carcinoma, and is likely to be indicative of the patients' prognosis.

Humans↗

PubMed2003

[Current progress of phenotypic modulation of vascular smooth muscle cells].

Proliferation and migration of vascular smooth muscle cells were the common pathological feature of development and progression of atherosclerosis, hypertension and vascular restenosis. Phenotypic modulation of vascular smooth muscle cells was the basis of its proliferation and migration. So, understanding the mechanisms of phenotypic modulation of these cells may be helpful to prevent and treat the diseases mentioned above. This paper will review the influence factors, signal transduction and transcription factors involved in phenotypic modulation of vascular smooth muscle cells.

Animals↗

PubMed2003

Value of echocardiography for observing left ventricular hypertrophy in the diagnosis of myocardial microvascular damage in hypertensives.

OBJECTIVE: To investigate the value of the echocardiographic observation of the left ventricular hypertrophy (LVH) in diagnosing myocardial microvascular damage in patients with essential hypertension (EH). METHODS: After intravenous injection with Quanfuxian (a contrast agent consisting of albumin and C3F8 prepared by Nanfang Hospital), the values of A (the maximum number of microbubbles accumulating in the local tissues for assessing the density of local microvessels), beta (the filling velocity of contrast agent for evaluating local blood flow velocity) and A x beta (the product of A and beta for estimating local myocardial blood flow) at rest and after dipyridamole injection were measured by intermittent harmonic imaging with myocardial contrast echocardiography (MCE). The ratios of A and beta along with the microvascular coronary flow velocity reserve (CFVR) were also calculated. RESULTS: Compared with the control group, the rest values of A, beta and A.beta in EH patients were higher, especially in those with LVH. After dipyridamole injection, the values of A, beta, A x beta and the ratios of A and beta, along with CFVR as well, were significantly lowered (P <0.01), and the reductions were especially obvious in LVH cases. As the hypertension exacerbated, the values of A and A x beta tended to increase in positive correlation with systolic and diastolic blood pressure (P <0.01), while the ratio of A and CFVR were decreased, the latter was inversely correlated with diastolic blood pressure (r=-0.55, P <0.01). Positive correlations were noted of the values of A and A x beta with the left ventricular mass and left ventricular mass index (P <0.01). CONCLUSION: EH patients, especially those with LVH, are characterized by increased rest myocardial microvascular blood flow, impaired myocardial microvascular flow reserve and endothelium independent vasodilation relaxing ability, and reduced capillary density, and these conditions tend exacerbate as the disease worsens. Microvascular function impairment should be suspected when complication of LVH arises in the EH patients. As a new important noninvasive technique, MCE can be a promising modality for diagnosing microvascular disease in essential hypertension.

Aged↗

PubMed2003

FBN1 mutation in Chinese patients with Marfan syndrome and its gene diagnosis using haplotype linkage analysis.

OBJECTIVES: To analyze the FBN1 mutations in Chinese patients with Marfan syndrome (MFS) and to make a genetic diagnosis based on haplotype linkage analysis for MFS. METHODS: Nine MFS families (17 patients) were analyzed with single strand conformation polymorphism (SSCP) and sequencing. Four primers were designed for the flanking sequences of FBN1 gene and used for haplotype-segregation analysis of MFS(B). RESULTS: SSCP band alteration was detected in the PCR products for exon 25 in MFS(A) II:1. Direct sequencing revealed a small 13 bp deletion; the deleted sequence is gccTc Tgcaccca at bases 3243-3456 of the cDNA in exon 25. This mutation was novel. MFS(B) families were analyzed using the haplotype linkage technique. The data suggested that MFS(B) families were linked to the FBN1 gene. The proband's daughter was an asymptomatic patient. CONCLUSION: The combination of mutation detection and chromosome haplotype analysis can provide better evidence for a genetic diagnosis of MFS.

Fibrillin-1↗

PubMed2003

[Diagnosis of several common alpha-thalassemia genotypes by multiplex fluorescence polymerase chain reaction].

OBJECTIVE: To develop an approach to a quick and accurate genetic diagnosis. METHODS: Byusing fluorescence primer, the fragments of alpha 1 and alpha 2-globin gene and internal control: beta-actin were amplified and then the PCR products were analyzed with Perkin Elmer ABI PRISMTM 377DNA Sequencer. Linkage analysis was also performed with (CA)n at the upstream of alpha 2-globin gene. The two methods were compared. RESULT: The fluorescence polymerase chain reaction and the linkage analysis gave the same result, and it was easy to distinguish different genotypes. CONCLUSION: The multipilx fluorescence polymerase chain reaction is simple, sensitive and feasible for rapid diagnosis of alpha thalassemia, and may be utilized for the genetic diagnosis of the pre-transplantation and the diagnosis by fetal nucleated erythrocytes in maternal blood.

Base Sequence↗

PubMed2003

[Inhibitory effect of antisense human telomerase reverse transcriptase(hTERT) on telomerase activity of human pulmonary giant cell carcinoma cell line(PLA-801D)].

BACKGROUND & OBJECTIVE: Telomerase has been thought to play an important role in the carcinogenesis in recent years. Human telomerase reverse transcriptase (hTERT) is a limiting component for telomerase activity. This study was designed to explore the effect of transfection of the full-length cDNA of antisense hTERT on the malignant phenotype of human pulmonary giant cell carcinoma cell line (PLA-801D) and its potential role in the gene therapy for cancers. METHODS: An antisense hTERT cDNA eukaryotic expression vector pcDNA3.1(-)-hTERT including the full length of hTERT cDNA sequence was constructed using recombinant DNA technique and transfected into human pulmonary giant cell carcinoma cells (PLA-801D) with liposome. The effect of antisense hTERT on the cellular proliferation capacity of PLA-801D cells was analyzed by the growth curve. The expression of hTERT mRNA was examined by reverse transcription polymerase chain reaction (RT-PCR). The telomerase activity was determined by telomeric-repeat amplification protocol enzyme-linked immunoassay (TRAP-ELISA). RESULTS: Antisense pcDNA3.1 (-)-hTERT eukaryotic expression have been constructed and was successfully transfected into the PLA-801D cells. The growth speed of PLA-801D transfected with antisense hTERT was significantly inhibited compared with the control cells, and the hTERT mRNA expression was inhibited, the relatively expression was only 15.7% of control cells, and telomerase activity was down-regulated about 82.4%. CONCLUSION: Full-length antisense hTERT cDNA can suppress hTERT mRNA expression and telomerase activity, and restrict the growth speed of tumor cells.

Carcinoma, Giant Cell↗

PubMed2003

[Analysis of caspases activity of hematopoietic progenitor cells and its significance in myelodysplastic syndromes].

OBJECTIVE: To investigate the changes of apoptosis and the activity of caspases 3 and 9 in bone marrow hematopoietic progenitor cells in myelodysplastic syndromes (MDS). METHODS: Bone marrow hematopoietic progenitor cells (including both CD(34)(+) and CD(34)(-) cells) were collected by negative selection in 34 patients with MDS. Apoptosis was measured with Annexin V assay and activities of caspases 3 and 9 by spectrophotometer. RESULTS: 1. Apoptosis was significantly increased in MDS-RA (39.5%, P < 0.01) and MDS-RAEB (31.0%, P < 0.05), but was not different statistically in MDS-RAEBt/AML (18.8%) compared with that of control. 2. Activities of caspases 3 and 9 increased 45 and 20 fold in MDS-RA, increased 14 and 2 fold in MDS-RAEB, respectively and was not increased in MDS-RAEBt/AML compared with that of control. 3. Apoptosis and activities of caspases 3 and 9 reduced in 3 cases of MDS-RAEB group who progressed into AML. CONCLUSION: Increased activities of caspases 3 and 9 may be one of causes of excessive apoptosis in MDS. With progress to AML, activities of caspases 3 and 9 and apoptosis reduced. Reduced activity of caspase 9 may result in apoptosis "escape" and progression into AML.

Apoptosis↗

PubMed2003

[Expression and regulation of a novel soluble adhesive molecule sCD226 on human endothelial cells].

AIM: To explore the expression and regulation of a novel soluble adhesive molecule sCD226 on HUVECs. METHODS: The contents of sCD226 and NO in culture supernatant of LPS activated human umbilical vein endothelial cells (HUVECs) were detected by ELISA and Greiss method respectively, and linear correlativity of contents between sCD226 and NO was analysed. The influence of anti-TNF-alpha mAb and iNOS inhibitor on LPS-induced sCD226 production was observed by ELISA. RESULTS: (1)LPS might markedly stimulate sCD226 production from HUVECs in a dose- and time-dependent manner. The amount of sCD226 came to 188.5 microg/L when endothelial cells were stimulated by 100 mg/L LPS for 3 days. (2)The production of NO and sCD226 showed linear correlation when HUVECs were stimulated by 100 mg/L LPS.(3)LPS-induced sCD226 production in HUVECs was inhibited significantly by anti-TNF-alpha mAb and iNOS inhibitor. CONCLUSION: LPS-activated-HUVECs can secret sCD226 and the generation of sCD226 is closely correlated with the production of NO and TNF-alpha.

Adhesives↗

PubMed2003

[Development and preliminary application of a double mAb sandwich ELISA for detecting soluble CD226].

AIM: To develop a double mAb sandwich ELISA for detecting sCD226 and apply it to clinical specimens. METHODS: The optimal concentrations of coating mAb and HRP-mAb, and the optimal diluents were determined. A double mAb sandwich ELISA then was established. The specificity, sentivity and stability of the method were identified. And clinical specimens were detected by this method. RESULTS: The optimal concentrations of coating mAb LeoA1 and HRP-mAb FMU3 were 2.5 mg/L and 1:400, respectively, and the optimal diluents for standard antigen and HRP-mAb were 1 g/L BSA 1 mL/L Tween20-PBS and 30 g/L PEG-PBS.The ELISA achieved satisfactory results in respect to specificity (no cross-reaction to human IgG, in block test blocking effect was does-dependent), sensitivity (the detected threshold was 110 ng/L) and stability (CV<10.2%). Statistical analysis showed that the serum sCD226 level in patients with rheumatoid arthritis (RA) was significantly higher than that in healthy adults. CONCLUSION: A double mAb sandwich ELISA with high specifity, and relative sensitivity for detection of sCD226 has been developed. It is shown to be an applicable method of detecting sCD226 in clinical specimens.

Antibodies, Monoclonal↗

PubMed2003

[Eukaryotic expression and application of human CD226 Ig fusion protein containing 3C protease-restricted site].

AIM: To construct, express and characterize the eukaryotic expression vector of encoding human CD226 (PTA1) extracellular region Ig fusion protein gene containing 3C protease-restricted site. METHODS: The gene fragment encoding extracellular region of human CD226 was cloned into the eukaryotic expression vector p-3C-Ig containing 3C protease-restricted site and human Ig Fc fragment gene. After sequencing, the vector was transfected into COS7 cells, and the expressed molecule was purified by affinity chromatography. Finally, the product was characterized by immunofluorescent staining and 3C protease digestion. RESULTS: After expression and purification, the Ig fusion protein could bind effectively to the CD226 ligand expressed on ECV304 cells. The Fc fragment could also be cut off by 3C protease, so that the CD226 extracellular fragment was obtained. CONCLUSION: The extracellular region of human CD226 Ig fusion protein with 3C protease-restricted site is expressed successfully in COS-7 cells, which lays the foundation for the structural and functional study of this molecule.

Animals↗

PubMed2003

[Establishment and characterization of human alloantigen induced T cell clones].

AIM: To estabilish and analyze stable human T cell clones cultured in-vitro. METHODS: The activated T cells from mixed lymphocyte culture (MLC) were cloned by limiting dilution using irradiated PBMCs as feeder cells. T cell clones were then characterized by immunofluorescence staining and flow cytometry analysis. RESULTS: 16 clones were obtained, of which all but one were alphabetaT cells. Among the 15 alphabetaT cell clones, 9 clones belonged to Th subset, including 3 Th0 and 6 Th2, and 6 clones belonged to Tc subset, including 5 Tc0 and 1 Tc2. CONCLUSION: Fifteen human T cell clones were successfully established, which lays the foundation for study on markers and function of Tc1 and Tc2 subsets.

Antigens, Differentiation, T-Lymphocyte↗

PubMed2002

[Single cell PCR for sex determination in preimplantation genetic diagnosis].

OBJECTIVE: To develop an efficient, rapid and reliable method for sex determination in preimplantation genetic diagnosis. METHODS: Nested PCR and fluorescent PCR were used to amplify amelogenin and IL-3 genes from human single lymphocytes and blastomeres. RESULTS: The amplification efficiencies of nested PCR and fluorescent PCR of man single lymphocyte/woman single lymphocyte/blastomere were 64.7%/65%/85.7%, and 72%/76%/86.9% respectively. The PCR products of the lymphocyte were exactly the same as those of the donor gDNA. The PCR products of blastomeres coming from the same embryo were all identical. CONCLUSION: The amplification efficiencies of nested PCR and fluorescent PCR are similar while fluorescent PCR is more conventional, time sparing and sensitive.

Adult↗