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Biomedical subjects

X Wu

Publications and source records attributed to X Wu.

At least 199 records · Page 11Linked to original sources
PubMed2001

Expression, purification and biochemical characterization of a recombinant phospholipase A2, with anticoagulant activity from Agkistrodon halys Pallas.

A cloned cDNA encoding a PLA2 from Agkistrodon halys Pallas was found to have conservative residues Glu53 and Trp70 but with Lys56 and Lys67 substituted by Thr56 and Asp67, respectively, when compared with sequences of other class II PLA2 with anticoagulant activity. It was inserted into a temperature-sensitive bacterial expression vector and effectively expressed in Escherichia coli RR1. The protein was produced as insoluble inclusion bodies and recovered by centrifugation after enzyme digestion. By washing to partial purification, the expression product was refolded and was purified by FPLC superose 12 to appear as a single band in SDS-PAGE. The recombinant protein proved to have obvious enzymatic, anticoagulant and hemolytic activities, which were removed after modification by p-BPB. These findings suggest that the pharmacological activities of this recombinant PLA2 may be related to its catalytic activity and warrant further research on the structure-function relationships of the pharmacological site of the PLA2 from Agkistrodon halys Pallas.

Animals↗
PubMed2001

Identification of key residues responsible for enzymatic and platelet-aggregation-inhibiting activities of acidic phospholipase A2S from Agkistrodon halys Pallas.

Site-directed mutagenesis was used to probe the structural and functional relationship of acidic phospholipase A2 from Agkistrodon halys Pallas. The mutants are AP-E6R (E6R), AP-D115K (D115K), AP-6R115K (E6R, D115K), AP-Y118M (Y118M), and AP-W119T (W119T). All mutants were inserted into a bacterial expression vector and effectively expressed in E. coli RR1. The purified recombinant enzymes were used to assay for enzymatic and inhibiting platelet aggregation activities. The enzymatic activities of AP-D115K, AP-Y118M and AP-W119T are close to that of denatured-refolded acidic phospholipase A2, while the enzymatic activities of AP-E6R, AP-6R1 15K are lower than that of denatured-refolded acidic phospholipase A2 (AP-WT). In these five mutants, AP-Y118M showed strongest inhibiting effect on platelet aggregation, which is the same as that of AP-WT, AP-W119T showed only modest activity and AP-E6R, AP-D115K, AP-6R115K showed little activity. To study the structural and functional relationships among these five mutants, molecular modeling of these five mutants was done. The roles of various amino acid residues in the enzymatic activity and pharmacological activity of acidic phospholipase A2 are discussed.

Adult↗
PubMed2001

[Establishment of platelet-mediated transmitochondrial cell model].

OBJECTIVE: To establish a transmitochondrial cell model for further researches on molecular genetics of mitochondrial related disease. METHODS: The fusion process was conducted between mitochondrial DNA-lacking rho degrees cell (a gift from NIH) and platelet using polyethylene glycol as fusion promoting reagent. The fusion cells were confirmed by PCR and electronic microscopic cytochemistry. The mitochondrial morphology and function of 3 families of Rett syndrome were investigated. RESULTS: The platelet-mediated transmitochondrial cell model was constructed successfully. The frequency of transformation ranged from 0.5 to 1.6 clones in 10(4) recipient cells. The mitochondrial vacuolation was occasionally observed in 2 cases of Rett syndrome. CONCLUSION: Transmitochondrial cell model can be applied to assessment of the mitochondrial morphology and function of fusion cells and is found to be of great use in evaluating the gene expression of mitochondrial genome at different levels.

Blood Platelets↗
PubMed2001

Induction of apoptosis in colon cancer cells by cyclooxygenase-2 inhibitor NS398 through a cytochrome c-dependent pathway.

Nonsteroidal anti-inflammatory drugs (NSAIDs) have shown cancer preventive activity in patients who took them frequently. These drugs can induce tumor cells to undergo apoptosis in vitro. NS398, a cyclooxygenase-2 (COX-2)-selective inhibitor, has been reported to cause apoptosis in cancer cell lines. Therefore, we examined its effect on 15 human colon cancer cell lines and investigated its mechanism of action. NS398 decreased cell viability in all of the cell lines. Tumor cells that expressed COX-2 were shown to be more sensitive to NS398 treatment. In three selected colon cancer cell lines, NS398-induced apoptosis was mediated by the release of cytochrome c from mitochondria and, consequently, by the activation of caspase-9 and caspase-3 and by the cleavage of poly(ADP-ribose) polymerase. In contrast, caspase-8 was not involved in NS398-induced apoptosis, which suggested that the cytochrome c pathway may play an important role in NS398-induced apoptosis in colon cancer cell lines. Therefore, the combination of NS398 with apoptosis-inducing drugs through cytochrome c-independent pathways may be warranted.

Apoptosis↗
PubMed2001

[The method of instantaneous pulse detection based on hybrid wavelet transform].

In this paper, we discuss the relation between matched filter and wavelet transform(WT), and point out that wavelet transform is just the matched filter with changeable detection template. According to this idea, the method of signal detection based on hybrid wavelet transform (HWT) is proposed. HWT in this paper means that in WT decomposition and reconstruction, we use two different mother wavelets. One is used as a changeable template for the pulses detection and the other is used for the characteristic enhancement of detected pulse. This method has been applied to the interference pulse detection in EEG signal. The experiment result shows that HWT has the good property for instantaneous signal detection.

Algorithms↗
PubMed2001

[Influence of scatter factor/hepatocyte growth factor on the growth and transmission of hepatocarcinoma SMMC 7721 cells].

OBJECTIVE: To explore the influence of scatter factor/hepatocyte growth factor (SF/HGF) on the growth and transmission of hepatocarcinoma SMMC 7721 cells by SF/HGF cDNA transfection. METHODS: Gene transfection was operated by lipofectin method. In vitro, SF/HGF and c-met expression was tested by ELISA and Western blot. Cell proliferation and motility were compared by growth curves and wound healing assays. In vivo, cells before and after transfection were implanted subcutaneously into nude mice respectively to observe tumor growth and metastasis. RESULTS: After transfection, the expression of SF/HGF reached 694 pg/ml, compared with 0.26 pg/ml before transfection; however the expression of c-met protein did not change obviously. Growth curves showed that cells after transfection proliferated more rapidly than those before transfection and had an increased capability of motility together with enlarged morphological changes. In vivo experiment, tumors originated from SF/HGF(+) cells grew faster than those from SF/HGF(-) cells and had embolism formed inside and metastasis in the corresponding lung tissues, whereas no such findings in SF/HGF(-) cell originated tumors. CONCLUSIONS: High expression of SF/HGF can stimulate tumor cell proliferation and metastasis in hepatocellular carcinoma

Animals↗
PubMed2001

Expression of basic fibroblast growth factor (bFGF), FGF receptor 1 and FGF receptor 2 in uterine leiomyomas and myometrium during the menstrual cycle, after menopause and GnRHa treatment.

BACKGROUND: To investigate whether basic fibroblast growth factor (bFGF) is involved in the growth regulation of human uterine leiomyomas the expression of bFGF and its receptors was measured in leiomyomas and myometrium obtained under different endocrine conditions. METHODS: The expression of bFGF, fibroblast growth factor receptor 1 (FGFR1) and fibroblast growth factor receptor 2 (FGFR2) was analyzed by immunohistochemistry and Western blot. RESULTS: Twenty-seven women with leiomyomas included eight in the proliferative phase, seven in the secretory phase, six after menopause and six after GnRHa treatment. In the proliferative phase, bFGF staining in leiomyomas was significantly stronger than in any other leiomyoma group. After GnRHa treatment, the expression of bFGF in both leiomyomas and myometrium was weaker than in the proliferative phase. The staining of FGFR1 was less intense in proliferative phase myometrium than in myometrium from any other group, significantly weaker than in the secretory phase. The leiomyomas demonstrated homogeneous cytoplasmic FGFR1 staining that was similar in all groups, except in the GnRHa treated patients where a more intense staining was observed, significantly stronger than in proliferative phase leiomyomas. No tissue differences were observed for staining of FGFR2 and no significant differences were observed between the different groups. Slightly less staining of FGFR2 was found in leiomyomas in the secretory phase but it did not reach statistical significance. The specificity of immunostaining was confirmed by Western blot. CONCLUSIONS: We suggest that the regulation of bFGF, and to some extent also its receptors in leiomyomas and in myometrium, is influenced by sex steroid hormones. However, the lack of differences in expression between leiomyomas and myometrium favors the view that bFGF does not necessarily contribute to the differences in growth regulation in these tissues.

Adult↗
PubMed2001

[Study of susceptibility loci located within Xp11 in attention deficit hyperactivity disorder].

OBJECTIVE: To detect the genetic relationship between monoamine oxidase(MAO) A type gene and attention deficit hyperactivity disorder(ADHD) in Chinese. METHODS: The haplotype-based haplotype relative risk(HHRR) and the transmission disequilibrium test(TDT) methods were used to analyze the genetic association and linkage in 60 ADHD children and their parents. RESULTS: In this sample were found significant association (chi(2)=4.90, P<0.05) and linkage (chi(2)=4.84, P<0.05) between the MAOCA 114bp allele and DSM-III-R-diagnosed ADHD in trios composed of father, mother and affected offspring. CONCLUSION: The above results suggested that ADHD was associated and in linkage with MAO A gene, and the susceptibility loci might reside in chromosome Xp11 for ADHD.

Attention Deficit Disorder with Hyperactivity↗
PubMed2001

[Study on the relationship between methylenetetrahydrofolate reductase gene C677T mutation and coronary heart disease].

OBJECTIVE: To investigate whether methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism is linked with coronary heart disease (CHD). METHODS: Transmission/disequilibrium test(TDT), sib transmission/disequilibrium test(STDT), and sibship disequilibrium test(SDT) were used. Forty-five CHD pedigrees with at least one CHD patient in the first degree relatives of probands were recruited from Oct. 1998 to Feb. 1999. Among those recruited were 21, 2 and 22 pedigrees with the genotypes of both parents known, one parental genotype unknown and both unknown, respectively. MTHFR genotype was measured by PCR-RFLP technique. RESULTS: Neither the TDT for 23 nuclear families with at least one parental genotype known or the STDT and SDT for 40 sibships found significant difference between the transmitted and untransmitted MTHFR gene 677T allele distributions. CONCLUSION: The above results suggest that MTHFR gene 677T allele is probably not linked with CHD in Chinese population.

Coronary Disease↗
PubMed2001

[Clinical significance of differential display cDNA fragment MRG98.2 expression in hepatocellular carcinoma].

OBJECTIVE: To search for the gene related to hepatocellular carcinoma (HCC), and to study its potential significance in liver oncogenesis. METHODS: The difference in mRNA expression among HCC, nontumorous liver tissue, and normal liver tissue was investigated by differential display technique. Ten hepatic tissues of hepatoma versus surrounding noncancerous liver tissues were examined with MRG98.2 as a probe in Dot blot analysis. Expression of vascular endothelial growth factor (VEGF) mRNA in above-mentioned samples was examined with reverse transcription-polymerease chain reaction (RT-PCR). RESULTS: Differential display cDNA fragment MRG98.2 was isolated from hepatoma samples. Dot blot analysis showed that MRG98.2 was expressed in 7 cases of HCC samples (7/10) but only in 2 of the surrounding noncancerous hepatic tissues (2/10). The expression of VEGF mRNA was upregulated in 6/7 of HCC samples expressed MRG98.2. CONCLUSIONS: MRG98.2 may be a gene related to HCC. Its expression in HCC correlates with VEGF mRNA. MRG98.2 expression is helpful in predicting a tendency toward invasion and metastasis of HCC or a poor prognosis.

Carcinoma, Hepatocellular↗
PubMed2001

Loss of phospholipids asymmetry in red blood cells contributes to anemia in uremic patients.

Anemia is common in dialysis patients. Change in phospholipids asymmetry in red blood cells (RBCs) may affect the removal of RBCs from the circulation and thus shorten the lifespan of RBCs. In the present study, we investigated phospholipids asymmetry in RBCs in uremic patients and its relationship with anemia. We studied 34 continuous ambulatory peritoneal dialysis (CAPD) patients (age: 51 +/- 15 years), 73 hemodialysis (HD) patients (age: 48 +/- 12 years), 8 pre-dialysis renal-failure patients (age: 42 +/- 21 years), and 16 healthy controls (age: 32 +/- 9 years). All patients were clinically stable. Phospholipids asymmetry as measured by phosphatidylserine exposure was determined by a flow-cytometric annexin V-binding assay. Hemoglobin levels were 93 +/- 20 g/L, 83 +/- 17 g/L, 78 +/- 21 g/L, and 145.8 +/- 12.5 g/L for CAPD patients, pre-dialysis patients, HD patients, and healthy controls respectively. Phosphatidylserine exposure in RBCs was significantly higher in uremic patients as compared with healthy controls, especially in HD patients--whose values were significantly higher than values seen in CAPD patients and pre-dialysis patients. No significant difference was seen in RBC phosphatidylserine exposure between pre-dialysis patients and CAPD patients. Cells positive for annexin V binding were 1.58%, 1.40%, 2.11%, and 0.71% for CAPD patients, pre-dialysis patients, HD patients, and healthy controls respectively. Significant reverse correlations were seen between annexin V and hemoglobin (r = -0.381, p < 0.001), and between annexin V and hematocrit (r = -0.355, p < 0.001). Our results suggest that (1) anemia is common in our uremic patients, especially in HD patients; and (2) anemia in uremic patients may be partly related to the loss of phospholipids asymmetry in RBCs.

Adult↗
PubMed2001

[Clinical study on treatment 82 cases of chronic primary glomerulopathy with deficiency of yin with damp-heat symptom with dan shao tang].

OBJECTIVE: To investigate the treatment effect of Dan Shao Tang on chronic primary glomerulopathy with deficiency of Yin with damp-heat symptom. METHODS: 132 cases of chronic glomerulopathy with deficiency of Yin with damp-heat symptom, which divided into two groups at random, the 82 cases which were the therapy group using Dan Shao Tang and west medicine, and the other 50 cases which treated only by west medicine. We observed the effect and indexes change including renal function, proteinuria, hematuria. RESULTS: The effective rate of the therapy group is 90.24%, and the effective rate of the control group is 66% (P < 0.05), The therapy group is superior to the control group in improving renal function, decreasing proteinuria and hematuria in evidence(P < 0.05). CONCLUSION: Dan Shao Tang is effective to treatment on chronic primary glomerulopathy with deficiency of Yin with damp-heat symptom.

Adult↗
PubMed2001

Immune privilege induced by cotransplantation of islet and allogeneic testicular cells.

OBJECTIVE: To induce islet allograft long-term survival through cotransplantation of islet cells with sertoli cells. METHODS: Testicular sertoli cells were prepared by digestion with collagenase, trypsin and DNase, and were cultured for 48 hours. Collagenase digested and Ficoll purified donor (Wistar rat) islets were cotransplanted with allogeneic sertoli cells in the absence of systemic immunosuppression. Terminal deoxynucleotidyl transferase-mediated X-dUTP nick-end labeling (TUNEL) was used to label apoptosis of lymphocytes surrounding the islet graft. RESULTS: Cotransplantation of islets and 1 x 10(7) sertoli cells reversed the diabetic state for more than 60 days in 100% (6/6) of the chemically diabetic Sprague Dawley rats. Grafts consisting of islets alone or islets plus 1 x 10(5) sertoli cells survived only for 5-6 days. Apoptosis of lymphocytes surrounding the islets was quite clear. CONCLUSION: Cotransplantation of islets with FasL+ sertoli cells induces local immune privilege and allows long-term graft survival without systemic immunosuppression.

Animals↗
PubMed2001

Basaloid squamous cell carcinoma of the esophagus: an immunohistochemical study of 8 cases.

OBJECTIVE: To explore the biological features of basaloid squamous cell carcinoma (BSC) of the esophagus. METHODS: Cytokeratins (CK4, CK18 and CK19), epithelial membrane antigen (EMA), carcino embryo antigen (CEA), alpha-smooth muscle antigen (alpha-SMA), S-100, laminin (LN), collagen IV (Col-IV), neural-specific enolase (NSE), proliferating cell nuclear antigen (PCNA) and p53 antibodies were used to detect the corresponding antigen expression in 8 cases of BSC with ABC immunohistochemical methods. RESULTS: Two kinds of BSC cell components have different responses to the above antibodies. For basaloid cells (BCs), 7 cases were positive for CK19, and were negative for the other 4 epithelial antibodies CK4, CK18, CEA and EMA. BCs of 4 cases were positive to the muscular antibodies alpha-SMA and S-100, and the hyaline degeneration in the tumor nests was positive for LN and Col-IV. BCs had a high index of PCNA, with an average level of 54%. For squamous cells (SCs), 7 cases were positive for the epithelial antigen CK4, CEA and EMA, but were negative for CK19, alpha-SMA and S-100. The index of PCNA of SC was low, with an average level of 25%. CONCLUSION: BSC of the esophagus is a high-malignancy tumor which is of multi-oriented differentiation. BCs represent basal cells which have the tendency of myoepithelial differentiation and have strong proliferation ability, whereas SCs represent typical squamous cell differentiation.

Carcinoembryonic Antigen↗
PubMed2001

[Effect of a new triclosan-containing mouth rinse on oral infection].

OBJECTIVE: To study the effect of a new Triclosan-containing mouthrinse--LIBO Anti-plaque mouth rinse on oral infection. METHODS: 1. Before and after the use of triclosan mouthrinse: the gingival data were checked and secorded; plaque sausples were collected, cultured in selective and non-selective media, bacteria were isolated, sounted, and compased. 2. With Streptococcus mutans and P. Gingivalis as experimental bacteria, triclosan and chlorhexidine (CHX) mouthrinses anti-bacterium substance, the minimum inhibitory concentrations (MICs) of the two rinses were compared. 3. Smooth plates with the film of Streptococcus mutans C were set in different mouthrinses and water. Observing the exfoliation of bacteria film from the plates in three agents. RESULTS: 1. Triclosan mouthrinse was effective to decrease the plaque index (PLI) and supragingival bleeding index (SBI). 2. The bacteria count obtained after use of triclosan mouthrinse was lower than that before using it. 3. The minimum inhibitory concentrations of triclosan mouthrinse against Streptococcus mutans C was much lower than that of chlorhexidine mouthrinse. 4. In triclosan mouthrinse, the bacterial films were most easily exfoliated from the plate. Triclosan mouthrinse has strongest anti-adhesion effect among the three tested agents. CONCLUSIONS: Triclosan mouthrinse has continuous disinfecting effect and help control the formation and adhesion of dental plaque.

Adult↗
PubMed2001

[Correction of occipito-posterior by maternal postures during the process of labor].

OBJECTIVE: To investigate the effect on correction of occipito-posterior (OP) by changing maternal posture during labor. METHODS: One hundred normal primigravida with head OP position in the latent phase of labor were randomly divided into 2 groups: Group A (n = 50), women were instructed to lay on the same lateral posture with the fetal spine during labor in order to correct the fetal position from OP to occipito anterior (OA); Group B (n = 50) lay on the opposite side to the fetal spine. The OP position was diagnosed by vaginal examination or B ultrasound, and the course of labor and mode of delivery were observed. RESULTS: Thirty-four women delivered vaginally (68%) in group A, with 27 of them turned to OA position (54%); spontaneously while they were 22 (44%) and 12 (24%) in group B respectively, a significant difference was shown (P < 0.005). The average time interval for the 1st stage was (13.5 +/- 6.5) hour and (17.1 +/- 7.2) hour for group A and B respectively, also a significant difference was noted (P < 0.01). CONCLUSION: To instruct women in labor to take the lateral recumbent position with the same side of fetal spine for correcting OP to OA is an effective method. It may increase vaginal deliveries and shorten the first stage of labor, thus reduce dystocia due to OP position. This method is simple and effective, and maybe adopted in most obstetric units.

Adult↗
PubMed2001

Analysis of lenti- and trans-lentiviral vector genetic recombination.

Lentiviral vectors hold great promise for gene therapy, and clinical trials to examine their safety and efficacy for treating human disease are being planned. The principle concern for safety is that genetic recombination among components of the vector could lead to the emergence of replication competent retrovirus (RCR). Using a sensitive method for detecting genetic recombination, we found that the current design of lentiviral vectors permits the generation of envelope-deficient recombinant lentivirus, stable integration of the recombinant into chromosomes of transduced cells, and mobilization of the recombinant genomes to other cells when pseudotyped with an exogenous envelope. We split the lentiviral packaging construct (Gag/Gag-Pol) into two separate parts: one that expresses Gag and Gag-Pro, and another that expresses Pol (reverse transcriptase [RT] and integrase [IN]) as a fusion partner of Vpr (Vpr-RT-IN). This "trans-lentiviral" vector efficiently transduces non-dividing cells and achieves titres greater than 10(6) U/ml or 10(8) IU/ml after concentration by ultracentrifugation. The trans-lentiviral vector disarms the Gag-Pol structure and prevents the generation of recombinants containing functional RT and IN. Since RT and IN are absolutely required for any type of RCR and DNA mobilization, this new class of lentiviral vector, in combination with our sensitive in vitro assay for monitoring regeneration of the gag-pol structure, offers a unique advantage for predicting vector safety for clinical applications.

Base Sequence↗