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Biomedical subjects

Li Li

Publications and source records attributed to Li Li.

At least 631 records · Page 35Linked to original sources
PubMed2002

Preparation of human single chain Fv antibody against hepatitis C virus E2 protein and its identification in immunohistochemistry.

AIM: To screen human single chain Fv antibody (scFv) against hepatitis C virus E2 antigen and identify its application in immunohistochemistry. METHODS: The phage antibody library was panned by HCV E2 antigen, which was coated in microtiter plate. After five rounds of biopanning,56 phage clones were identified specific to HCV E2 antigen. The selected scFv clones were digested by SfiI/NotI and DNA was sequenced. Then it was subcloned into the vector pCANTAB5E for expression as E-tagged soluble scFv. The liver tissue sections from normal person and patients with chronic hepatitis B and chronic hepatitis C were immunostained with HCV E2 scFv antibody. RESULTS: The data of scFv-E2 DNA digestion and DNA sequencing showed that the scFv gene is composed of 750 bp. ELISA and immunohistochemistry demonstrated that the human single chain Fv antibody against hepatitis C E2 antigen has a specific binding character with hepatitis virus E2 antigen and paraffin-embedded tissue, but did not react with liver tissues from healthy persons or patients with chronic hepatitis B. CONCLUSION: We have successfully screened and identified HCV E2 scFv and the scFv could be used in the immunostaining of liver tissue sections from patients with chronic hepatitis C.

Amino Acid Sequence↗
PubMed2002

Retroviral gene therapy vectors for prevention of excimer laser-induced corneal haze.

PURPOSE: To determine the in vivo efficacy and safety of a retroviral vector bearing an antiproliferative dominant negative mutant cyclin G1 (dnG1) construct, when used for the prevention of corneal haze after phototherapeutic keratectomy (PTK). METHODS: For in vivo efficacy studies, a 6-mm-diameter, 150-microm-deep transepithelial PTK, performed with a clinical 193-nm ArF excimer laser (VISX Star2, Santa Clara, CA) was performed on the left eyes of 20 adult New Zealand White rabbits. The surgically altered eyes were subsequently treated with eye drops containing: a retroviral vector bearing a dnG1 construct (dnG1; n = 7), a control retroviral vector (null vector) bearing only the neomycin resistance, neo(r), gene (n = 7), or a retroviral vector bearing an antisense cyclin G1 (aG1) construct (n = 6). The time of closure of the corneal epithelial defect was monitored daily with fluorescein staining. Corneal haze was evaluated before surgery and at 2, 3, and 4 weeks after surgery, with a digital imaging system. Biodistribution studies for detection of potential vector dissemination to nontarget organs were conducted by PCR-based assay. RESULTS: The re-epithelialization rate was similar among treatment groups, with complete closure of the corneal epithelial defect at 72 hours (P > 0.05). Significant corneal haze developed in the null and aG1 vector-treated groups (P <or= 0.05) at 3 to 4 weeks after PTK. In contrast, development of corneal haze was inhibited in the dnG1 vector-treated group when compared with the null vector-treated group (P < 0.05). In parallel, a dramatic reduction to complete abrogation of abnormal extracellular matrix production was noted in the dnG1 vector-treated corneas when compared with the null and aG1 vector-treated groups. Biodistribution studies showed no evidence of vector dissemination in neighboring and distant organs. CONCLUSIONS: At therapeutic doses, eye drop application of the dnG1 retroviral vector is safe and effective in inhibiting development of corneal haze after PTK in rabbits.

3T3 Cells↗
PubMed2002

Aqueous oxygen hyperbaric reperfusion in a porcine model of myocardial infarction.

OBJECTIVES: The purpose of the study was to test the hypothesis that intracoronary aqueous oxygen (AO) hyperbaric reperfusion reduces myocardial injury after prolonged coronary occlusion. Background. Attenuation of ischemia/reperfusion injury by the use of hyperbaric oxygen (HBO) administered during reperfusion has been demonstrated for a wide variety of tissues, including myocardium. We have recently developed a more practical, catheter-based, site-specific method for delivery of oxygen at hyperbaric levels with aqueous oxygen infusion. METHODS: Following a 60-minute balloon occlusion of the left anterior descending coronary artery in swine, intracoronary AO hyperoxemic perfusion (50 mL blood/minute; 1.5 mL AO/minute; mean pO2 = 834 104 mmHg) was performed for 90 minutes after a 15-minute period of normoxemic autoreperfusion (physiologic reperfusion). Control groups consisted of autoreperfusion alone; active normoxemic perfusion (50 mL/minute) for 90 minutes; and hyperoxemic perfusion with a hollow fiber oxygenator (HFO) for 90 minutes. Results. A significant improvement in left ventricular ejection fraction was noted by ventriculography at 105 minutes of reperfusion (ANOVA, p < 0.05), compared to the 15-minute autoreperfusion period, only in the AO and HFO groups. Mean percent infarct size (area of necrosis)/(area at risk), quantitative post-mortem hemorrhage score, and myocardial myeloperoxidase levels at 3 hours of reperfusion were significantly less in the AO group (ANOVA, p < 0.05), but not in the HFO group, compared to normoxemic groups. Conclusions. The results demonstrate that intracoronary hyperbaric reperfusion with AO, but not with a membrane oxygenator, attenuates myocardial ischemia/reperfusion injury.

Analysis of Variance↗
PubMed2002

[A clinical trial using zidovudine and lamivudine plus indinavir triple therapy in Chinese individuals with human immunodeficiency virus infection].

OBJECTIVE: Evaluation of high active antiretroviral therapy (HAART) in human immunodeficiency virus and acquired immunodeficiency syndrome (HIV/AIDS) patients receiving combined antiretroviral therapy in China. METHODS: We initiated the first efficacy trial of zidovudine (AZT) 600 mg/d and lamivudine (3TC) 300 mg/d (brand name: Combivir) plus indinavir (2 400 mg/d) in 15 Chinese chronically infected with HIV in May 1999 at Beijing. RESULTS: There was a rapid reduction of 2.7 log in the plasma viremia levels in 15 cases 3 months, after treatment, from a mean baseline of 90 743 copies/ml. The mean CD(4) cell counts increased by 67 cells/microliter from a baseline mean value of 471 cells/microliter and the mean CD(8) cell counts reduced by 192/microliter after 12 months of therapy. The ratio of CD(4)/CD(8) increased from 0.35 to 0.56. The average naive CD(4) cell (CD(45)RA + CD(62)L +) count and naive CD(8) cell (CD(45)RA + CD(62)L +) count increased 42 and 19/microliter respectively after one-year treatment. This drug regimen was well tolerated, with mild nausea in all, transient elevated serum bilirubin in three and kidney stone in two patients. CONCLUSION: It is effective for the virus with different genotype. The results will form a scientific foundation for the development of therapeutic strategies for HIV infection in China.

Adult↗
PubMed2002

[Expression and role of placental vascular endothelial growth factor in patients with pregnancy induced hypertension].

OBJECTIVE: To investigate the expression of placental vascular endothelial growth factor (VEGF) and its relationship with construction of placental vascular network, placental weight and the newborns' weight in patients with pregnancy induced hypertension (PIH). METHODS: Twenty-five patients with PIH and twenty-five normal late pregnant (NLP) women in the third trimester were observed in this study. The expression of VEGF protein in placental, the placental vascular density were determined by Western blot and immunohistochemical F8 staining respectively. RESULTS: The VEGF values in patients with PIH and NLP were 24 793 +/- 6 579 and 41 903 +/- 11 009, and the vascular densities were (61 +/- 11) and (78 +/- 11) counts/400 x vision respectively. They were both significantly different in both groups and were closely related to the severity of PIH (P < 0.01). Placental weight and the newborns' weight in patients with PIH [(460 +/- 59) g, (3 176 +/- 503) g respectively] were also significantly decreased compared with NLP [(573 +/- 99) g, (3 468 +/- 493) g respectively], but the new newborns' length had no significant difference between the two groups (P > 0.05). In NLP group, placental vascular density, placental weight and the newborns' weight all had a significantly positive correlation with VEGF (P < 0.01, r = 0.823, 0.671, 0.888 respectively) and in PIH group, the situation was the same (P < 0.01, r = 0.905, 0.859, 0.732 respectively), but the new newborns' length had no correlation with VEGF (P > 0.05). CONCLUSION: It shows that the reduced expression of VEGF in placenta of patients with PIH may be one of the important factors responsible for decreased placental vascular density and fetal intrauterine growth restriction.

Adult↗
PubMed2002

[Preparation of human single chain Fv antibody specifically against hepatitis C virus E2 antigen].

OBJECTIVE: To identify human single chain Fv antibody (ScFv) against hepatitis C viral E2 antigen and its value clinically. METHODS: The recombinant phages were panned by E2 antigen which was coated in a microtiter plate. After five rounds of biopanning, 56 phage clones were identified specific to E2 antigen. The affinity and specificity of ScFv were evaluated by ELISA and immunohistochemistry, respectively. RESULTS: The data of E2-ScFv DNA digestion and DNA sequencing showed that the ScFv gene was composed of 750bp. ELISA and immunohistochemistry demonstrated that the human single chain Fv antibody against HCV E2 antigen had a specific combination character with hepatitis C virus E2 antigen. CONCLUSIONS: ScFv, having a sutestantial affinity and specificity and being easy to prepare, is valuable in the detection of HCV E2 antigen.

Amino Acid Sequence↗
PubMed2002

[Correlative study between portal vein pressure and portal hemodynamics in patients with portal hypertension].

OBJECTIVE: To explore the characteristics of the portal vein hemodynamics and the correlation with the portal vein pressure. METHODS: There were 41 cases of hepatic cirrhosis complicating portal hypertension. The liver function was graded Child-Pugh A+B in 31 cases and Child-Pugh C in 10 cases. The inner-diameter and blood stream speed of the portal vein (PV), the spleen vein (SV) and the superior mesentery vein (SMV) were measured by the color Doppler ultrasonography. The vascular acreage and blood flow volume were calculated. The portal vein pressure was directly measured during the operation. Thirty-two healthy people and 26 patients with chronic hepatitis B (CHB) served as controls in this study. RESULTS: The inner-diameter of the three veins was obviously wider and the blood flow speed was slower in two portal hypertension groups than in CHB and normal groups (P<0.01). In Child C group, the speed was the slowest. The speed of SV and SMV in two hypertension groups did not show any significant difference (P>0.05). In Child A+B group, the blood flow volume of the three veins was larger than that in normal and CHB groups (P<0.01 or P<0.05). The volume of PV was less in Child C group than Child A+B group (P<0.01), but the volume of SV and SMV was not obviously different (P>0.05). In Child A+B group, the portal vein pressure (Ppv) had a close correlation with the portal vein width, blood flow quantitation (Qpv), and blood stream volume (Qsv) of the spleen vein. CONCLUSIONS: The Qpv in Child A+B grade can be measured by the color Doppler ultrasonography technique, and the portal vein pressure can be monitored easily by the equation of Ppv=1.8951+0.0011Qpv.

Adult↗
PubMed2002

[Clinical and pathological characteristics and pathogenesis of autoimmune hepatitis].

BACKGROUND: To explore the clinical and pathological characteristics and pathogenesis of autoimmunohepatitis (AIH). METHODS: The serum and liver biopsy specimens and clinical data of 26 cases with patients with AIH were analyzed and scored according to the criteria of International autoimmune hepatitis (IAIHG, 1999). The changes of dendritic cells (DC) in the liver tissues were observed with a panel of DC markers (CD-80/B7-1, CD-86/B7-2, CD-1a and HLA-DR) and immunohistochemistry, and the activation of hepatic stellate cells (HSC) and the expression of TGF-alpha were also detected. Liver tissue specimens from 10 patients with chronic viral hepatitis B and C respectively and 5 normal liver specimens were chosen as controls. RESULTS: Mean aggregate scores of 26 AIH cases, including 21 cases of type B (80.8%) and 5 cases of type C (19.2%), which were 18.6 +/- 1.4 and 19.1 +/- 2.1 respectively. There were significant differences between the type B and type C in the average age levels of serum ALT and AST, and alpha-Glo (P <0.001 or P< 0.01 or P <0.05). Histological features of all the AIH liver tissues showed the lesions of chronic active hepatitis such as interface hepatitis/piecemeal necrosis (100%), obvious lobular inflammation (type B 95.2%, type C 100%), bridging necrosis (57.1% type B, 80.0% type C, P<0.05), rosetting of liver cells (71.4% type B, 100% type C, P<0.01), central lobular confluent necrosis (33.3% type B, 80.0% type C, P<0.001), predominant plasmacytic infiltration (type B 95.2%, type C 20.0%, P<0.001). The rates of increased and concentrated DC in the portal and lobular areas, especially in the active lesions in type B and type C AIH were 85.7% (18/21) and 5/5 respectively. It was found that DC and lymphocytes surrounded the hepatocytes which partly expressed HLA-DR antigen, while there were no or a few HLA-DR positive hepatocytes in controls. Meanwhile, the number of alpha-SMA positive HSC and the expression of TGF- were obviously increased in AIH liver tissues. CONCLUSIONS: Several clinical and pathological features of AIH were identified in this study. As an antigen-presenting cell, DC might play an important role in the pathogenesis of AIH. In China, sub-type B of AIH might be more frequent than sub-type C and there were differences in clinical aspects, serology and pathology between the two types.

Adolescent↗
PubMed2002

[Inhibitation of tumor angiogenesis, growth and metastasis by blocking VEGF paracrine pathway].

Solid tumors require an adequate vascular supply to grow beyond a certain dimension. It is known that formation of new blood vessels in tumor is mediated by unbalanced expression of angiogenic factors and their inhibitors. Among the former, the vascular endothelial growth factor (VEGF) has been assumed prime candidacy as a major positive physiological effector. To investigate the role of VEGF in angiogenesis associated with development of breast cancer, a sense VEGF and an anti-sense VEGF expression plasmids were constructed, and then were introduced into a human breast carcinoma cell line, MCF-7, expressing middle level of endogenous VEGF. Anti-sense VEGF(121) transfected MCF-7 cells that expressed reduced constitutive levels of VEGF and showed the same growing potential as untransfected MCF-7 cells in vitro, but it showed longer latency, smaller tumor, slower growth and prolonged survival time compared to parental or sense VEGF(165) transfected MCF-7 cells in vivo. Moreover, the tumors derived from anti-sense VEGF(121) transfected MCF-7 cells characterized by minimal vascularization and extensive necrosis. Finally, mice with primary subcutaneous tumors treated with intratumoral administration of anti-sense VEGF, or the plasmid expressing extracellular domain of the Flk-1 VEGF receptor (sFlk-1) followed by electroporation, showed significant tumor suppression. These results suggest that VEGF plays a major angiogenic role in breast cancer and a strategy, which blocks the VEGF paracrine pathway, may provide a means to control tumor growth topically without the risk of systemic antiangiogenesis.

3T3 Cells↗
PubMed2002

Clinical implications of increased expression of CD40L in patients with acute coronary syndromes.

OBJECTIVE: To investigate clinical implications of expression of CD40L in monocytes and changes in serum soluble CD40L in patients with acute coronary syndromes (ACS). METHODS: Sixteen control and 56 patients, including 24 with stable angina (SA), 20 with unstable angina (UA) and 12 with acute myocardial infarction (AMI) enrolled in this study. Expression of CD40L in monocytes was analyzed by flow cytometry and sCD40L levels were measured by ELISA. RESULTS: Expression of CD40L in monocytes and serum levels of sCD40L in UA and AMI patients were higher than in SA patients and controls. In patients with AMI, sCD40L levels showed no significant increase when compared to patients with UA, while AMI patients had a peak level of sCD40L at 24 hours after AMI. PTCA induced a marked rise in sCD40L levels in all patients, while CD40L expression in monocytes showed no difference between patients with PTCA, before and after. CONCLUSION: Enhanced level of serum sCD40L may be a reliable prognostic indicator for ACS and may represent a marker of coronary disease activity.

Angina Pectoris↗
PubMed2002

[The role of transforming growth factor-beta(1) in smoking-induced chronic bronchitis and emphysema in hamsters].

OBJECTIVE: To study the role of transforming growth factor-beta(1) (TGF-beta(1)) in the pathogenesis of chronic bronchitis and emphysema. METHODS: An animal model of chronic bronchitis and emphysema was developed in hamsters by chronic smoke inhalation. The expression of TGF-beta(1) mRNA and protein in the pulmonary tissue was observed. The bronchial epithelia was stimulated with cigarette smoke extract (CSE) in vitro and the expression of TGF-beta(1) was measured. RESULTS: 3 months after smoking, the animals developed chronic bronchitis and emphysema. TGF-beta(1) immunoreactivity in the pulmonary tissue and cultured bronchial epithelia increased significantly as compared to the normal control (2.75 +/- 0.23 vs 0.84 +/- 0.39, P = 0.001 and 2.67 +/- 0.16 vs 0.85 +/- 0.54, P = 0.001). The expression of TGF-beta(1) mRNA was also increased in the animal model (1.28 vs 0.98). CONCLUSIONS: Smoking can induce over-expression of TGF-beta(1) in bronchial epithelia, which may be one of the mechanisms for smoking-induced chronic bronchitis and emphysema.

Animals↗
PubMed2002

[A preliminary study on the heterogeneity of preS2 region in hepatitis B virus].

OBJECTIVE: To investigate the mutation of the preS2 gene sequence of HBV and clarify the significance of HBV quasispecies groups in the patients with chronic HBV infection. METHODS: A set of specific primers were synthesized according to HBV DNA sequence of a Chinese strain. The preS2 gene region was amplified by PCR method from the sera of 51 patients with chronic HBV infection, and the PCR products from 5 patients were subcloned into pGEM Teasy vectors. Polyacrylamide gel electrophoresis (PAGE) was employed to display the deletion mutations, clones with differential length were selected and sequenced. Sequence comparison was made to find the difference. RESULTS: When analyzed by PAGE, 2 approximately 3 bands were displayed in the PCR products from 52.9% (27/51) patients. This phenomena of multiple bands in PAGE was detected in both HBeAg (36.1%) and anti-HBe (93.3%) positive patients, the difference between the 2 groups being statistically significant (P < 0.01). Analysis on deduced amino acid sequence showed the deletion mutations were in the N-terminal half of the preS2-encoded protein. CONCLUSION: There is a hot deletion region in preS2 gene sequence. These deletion mutations were more frequently found in patients with both anti-HBe and HBV DNA positivity. The deletion may influence the recognition by neutralizing antibodies. Our results suggest that there are HBV quasispecies in patients with chronic HBV infection.

Gene Deletion↗
PubMed2002

[Epitope mapping of hepatitis C virus non-structure protein 5 from a 7 peptide phage library by using immobilized specific monoclonal antibody].

OBJECTIVE: To screen HCV NS5 mimotopes by using monoclonal antibody and phage peptide library. METHODS: By using HCV NS5 monoclonal antibody as selective molecule, a 7 peptide phage library was biopanned and positive clones were selected by ELISA, competition assay and DNA sequencing. RESULTS: Twelve positive clones were chosen for DNA sequencing. From the experiment and sequencing comparison results, one epitope was confirmed as the mimotope of HCV NS5. CONCLUSIONS: HCV mimotope is obtained by phage peptide library screening. The result provides a new approach for HCV therapy and vaccine development.

Amino Acid Sequence↗
PubMed2002

The homeobox gene BARX2 can modulate cisplatin sensitivity in human epithelial ovarian cancer.

Epithelial ovarian cancer (EOC) is the most common cause of death from gynaecological malignancy. Resistance to platinum chemotherapy is a major reason for treatment failure and poor prognosis. The human homeobox gene BARX2 is located within a minimal region at 11q25 that is associated with frequent loss of heterozygosity (LOH) and adverse survival in EOC. BARX2 is a transcription factor known to regulate transcription of specific cell adhesion molecules in the mouse. We have previously shown that BARX2 expression is low in clear cell/endometrioid and high in serous adenocarcinomas of the ovary, histologic variants that are less and more sensitive, respectively to platinum chemotherapy. The aim of this study was to define whether BARX2 could modulate sensitivity to cisplatin in human epithelial ovarian cancer. In two cell line series sequentially derived from ovarian cancer patients pre- and post-cisplatin chemotherapy, BARX2 expression was downregulated in the cell lines established upon tumor recurrence after platinum therapy. Transfection of BARX2 into a platinum resistant cell line significantly reversed cisplatin resistance compared with its isogenic platinum sensitive parent, in both growth inhibition and clonogenic assays. Taken together, our data demonstrate that the homeobox gene BARX2 may be a biological factor involved in determining sensitivity or resistance to the cytotoxic effects of cisplatin.

Blotting, Northern↗
PubMed2002

[Synergetic transactivating functions of HCV core and truncated HBV middle surface protein].

OBJECTIVE: To investigate the synergetic transactivating functions of HCV core and truncated HBV middle surface proteins. METHODS: Two recombinant expression plasmids harboring HCV core and C-terminally truncated HBV middle surface protein gene were constructed, respectively. The plasmids were transfected into HepG2 cells and cotransfected HepG2 cells with reporter plasmid pSV-lacZ by lipofectamine plus reagents. The transient expressed viral proteins were identified at the transcription and translation levels. The activity of beta-galactosidase was detected, which reflected the transactivating function of the proteins. RESULTS: The protein expression of plasmids was detected in soluble cell extracts of transiently transfected HepG2 cells. HCV core protein activated the beta-galactosidase expression at a value of 4.6 times higher than the control, while C-terminally truncated HBV middle surface protein activated at a value of 3.2 times. It reached 8.4 times transfected with the plasmids simultaneously. The transactivating effect was dose dependent. CONCLUSIONS: It is suggested that the two kinds of virus proteins have transactivating effect on SV40 early promoter/enhancer, and they act synergistically. These contribute to explain the mechanisms of liver injury or tumorigenesis induced by HCV or/and HBV infection.

Hep G2 Cells↗
PubMed2002

Effect of superior fiber complex on insulin sensitivity index and blood lipids in non-insulin dependent diabetes mellitus rats.

OBJECTIVE: To explore the factors affected insulin sensitivity index (ISI) and the effects of superior fiber complex (SFC) on ISI and blood lipids in non-insulin dependent diabetes mellitus (NIDDM) rats. METHODS: Twenty-six male Wistar rats were injected with low dose of streptozotocin and fed a diet with high calorie and high fat for ten weeks and glucose tolerance (GTT), fasting insulin (FINS), total cholesterol (TC) and triglyceride (TG) were measured while area under curve (AUC) and insulin sensitivity index (ISI) were also calculated. The results were compared with those from 7 normal control rats. Multi-factor regression analysis was used to analyze those factors affected ISI. In the same experiment, 13 rats with diabetes mellitus were treated with Superior Fiber Complex (SFC) for 8 weeks and the results were compared with the pre-treated data. RESULTS: Compared with the control group, AUC in the diabetic group was larger, and FINS, TC and TG were higher; but ISI was lower. Therefore, The TG and AUC was the major factor affected ISI. TC and TG were lowered and AUC was reduced and ISI increased. CONCLUSION: High TG and impaired glucose tolerance (IGT) are main risk factors of ISI in the rat model, and SFC could increase ISI, decrease high blood lipids and prevent IGT.

Animals↗