Biomedical subjects

Xue-Feng Wang

Publications and source records attributed to Xue-Feng Wang.

At least 19 recordsLinked to original sources

PubMed2006

Decreased expression of thyroid receptor-associated protein 220 in temporal lobe tissue of patients with refractory epilepsy.

PURPOSE: TRAP220 (thyroid hormone receptor-associated protein) functions as a coactivator for nuclear receptors and stimulates transcription by recruiting the TRAP mediator complex to hormone responsive promoter regions. Thus, TRAP220 enhances the function of thyroid/steroid hormone receptors such as thyroid hormone and oestrogen receptors. This study investigated the expression of TRAP220 mRNA and protein level in epileptic brains comparing with human control. METHODS: We examined the expression of TRAP220 mRNA and protein levels in temporal lobes from patients with chronic pharmacoresistant epilepsy who have undergone surgery. RESULTS: Expression of TRAP220 mRNA and protein was shown to be decreased significantly in the temporal cortex of the patients with epilepsy. CONCLUSIONS: Our work showed that a decrease in TRAP220 mRNA and protein levels may be involved in the pathophysiology of epilepsy and may be associated with impairment of the brain caused by frequent seizures.

Adolescent↗

PubMed2006

Inhibitory effects of pesticides on proteasome activity: implication in Parkinson's disease.

Epidemiological studies have suggested a correlation of pesticides and Parkinson's disease (PD) while genetic and biochemical studies have implicated the ubiquitin-proteasome system (UPS) in the pathogenesis of PD. In the present studies, we tested the hypothesis that pesticide exposure increases the risk of developing PD by inhibiting the UPS. The effects of pesticides on proteasome activity were examined in SK-N-MC neuroblastoma cells overexpressing a GFP-conjugated proteasome degradation signal, GFP(u). Six out of 25 representative pesticides, including rotenone, ziram, diethyldithiocarbamate, endosulfan, benomyl, and dieldrin, showed inhibitory effects on proteasome activities at low concentrations (10 nM to 10 microM). Unlike proteasome inhibitors, they did not inhibit 20 S proteasome activities in cell lysates. Except for rotenone, the other five pesticides did not induce significantly cellular oxidative stress. The cytotoxic effects of these pesticides were closely correlated with proteasome inhibition. Our results suggest proteasome inhibition as a potential mechanism for the epidemiological association of pesticides and PD.

Cell Death↗

PubMed2006

Expression of cancer-testis antigen (CTA) in tumor tissues and peripheral blood of Chinese patients with hepatocellular carcinoma.

To investigate the expression of cancer-testis antigen (CTA) in Chinese patients with hepatocellular carcinoma (HCC), and the relationship between CTA gene expression and clinical indexes, we used one-step reverse transcription polymerase chain reaction (RT-PCR). The expression of the CTA mRNA was investigated in the tissues of HCC and corresponding peripheral blood of 37 patients with HCC. Fifteen samples of cirrhotic tissues and 15 normal tissues were examined with the same method. Two kinds of CTA (SSX-2 and SSX-5) showed high-specific and high-frequent expression in HCC tissues, but neither of them could be detected in adjacent non-HCC tissues. In corresponding peripheral blood of HCC tissues, the positive expression rate of the SSX-2 and SSX-5 mRNA was not very high. No relationship was found between the expression of CTA and clinical indicators such as age, sex, tumor size, TNM staging, serum AFP level and infection with hepatitis virus. In 15 patients with cirrhosis and 15 other non-tumor patients, none of the SSX-2 and SSX-5 mRNA was detected in liver tissue or peripheral blood. High frequency and specificity of CTAs in HCC indicates that their products may be new potential promising targets for antigen-specific immunotherapy of HCC. High frequent co-expression of the two genes in HCC provides a possibility of polyvalent vaccinations for HCC. Specific expression of CTAs was observed in AFP-negative HCC, suggested applying their mRNA as tumor markers to detect circulating HCC cells as adjuvant diagnostic tool and as indicators of recurrence and prognosis.

Adolescent↗

PubMed2006

[Bayesian statistics-based method for genetic linkage analysis].

Bayesian School as one of the important statistical schools is different from the Classical Statistics, and the Bayesian methods have been widely used in many fields of modern sciences. In the present paper, we discussed the application of Bayesian method in linkage analysis, including the Bayesian estimation of recombination fraction, linkage testing based on the Bayes Factor and the Bayesian approach for genetic linkage map construction via Markov chain Monte Carlo algorithm. Simulation study and real data analysis were performed using SAS/IML software, and the validity and practicability of Bayesian method in genetic linkage analysis were thus verified.

Bayes Theorem↗

PubMed2006

[Dingchuantang decoction restores the imbalance of TH2/TH1 in mice infected by respiratory syncytial virus].

OBJECTIVE: Dingchuantang is a traditional Chinese medicine decoction which has the Qing, Xuan and Jiang components which have the ability to dispel (Xuan), depress (Jiang) and heat clear or febrigugal (Qing). It has been used for asthma and respiratory syncytial virus (RSV) infection. However, the therapeutic mechanisms of the decoction have not been identified. To understand the mechanism of the anti-RSV property of Dingchuantang, this study investigated the effects of Dingchuantang and its three components on the levels of interleukin-4 (IL-4) and interferon-gamma (gamma-IFN) in mice infected by RSV. METHODS: One hundred and twenty mice were randomly assigned into Normal, Infected, Dingchuantang-treated, Qing component-treated, Xuan component-treated and Jiang component-treated groups (n=20 each). The RSV infection model was prepared in the rats from the last 5 groups. The 4 treatment groups were administered with Dingchuantang, Qing component, Xuan component and Jiang component by gastric lavage respectively 2 hrs after RSV innoculation. The contents of RSV in the lungs were tested by reverse transcription polymerase chain reaction (RT-PCR). The levels of IL-4 and gamma-IFN in broncho-alveolar lavage fluid (BALF) were measured by enzyme linked immunosorbent assay (ELISA). RESULTS: The contents of RSV of lungs in the Dingchuantang-treated group, and Qing and Xuan component-treated groups were significantly lower than those in the untreated Infected group. There was no significant difference between the Jiang component-treated and the Infected group. Dingchuantang treatment decreased the IL-4 level and increased the gamma-IFN level. The Xuan and Jiang component treatment decreased the IL-4 level but had no effect on the gamma-IFN level, while the Qing component treatment increased the gamma-IFN level but had no effect on the IL-4 level. CONCLUSIONS: Dingchuantang can inhibit RSV reproduction and this effect works by Qing and Xuan components. Dingchuantang can also restore the imbalance TH2/TH1 by depressing IL-4 levels, worked by Xuan and Jiang components, and increasing gamma-IFN levels, worked by Qing component.

Animals↗

PubMed2005

[Role of bcl-2 transcriptional regulation induced by calmodulin I pressure overload rat hypertrophic hearts].

This study was designed to evaluate the role of bcl-2 transcriptional regulation induced by calmodulin I (CaM I) in pressure overload rat hypertrophic hearts. The model of hypertensive Sprague-Dawley rat was established by abdominal aortic constriction. The hearts were collected four weeks after abdominal aortic constriction. Velocity and isopyknic gradient centrifugation was employed to fractionate rat myocardial nuclei. Western blot analysis revealed a marked increase in phosphorylated cAMP response-element binding protein (pCREB) of cardiac hypertrophy group compared with that in control group (P<0.05), while the protein level of cAMP response-element binding protein (CREB) was constant (P>0.05). Immunohistochemistry results showed a significant increase of CaM I protein in cardiac hypertrophy group relative to the control group (P<0.05). Nuclear run off transcription assay displayed a significant increase in bcl-2 mRNA treated with trifluoperazne compared with non-drug treatment (P<0.05). The results obtained suggest that the transcription of bcl-2 is possibly regulated by CaM I hypertrophic rat hearts, and CREB phosphorylation seems to be a minor factor in bcl-2 transcriptional regulation.

Animals↗

PubMed2005

Effect of liniment levamisole on cellular immune functions of patients with chronic hepatitis B.

AIM: To explore the effects of liniment levamisole on cellular immune functions of patients with chronic hepatitis B. METHODS: The levels of T lymphocyte subsets and mIL-2R in peripheral blood mononuclear cells (PBMCs) were measured by biotin-streptavidin (BSA) technique in patients with chronic hepatitis B before and after the treatment with liniment levamisole. RESULTS: After one course of treatment with liniment levamisole, the levels of CD3(+), CD4(+), and the ratio of CD4(+)/CD8(+) increased as compared to those before the treatment but the level of CD8(+) decreased. The total expression level of mIL-2R in PBMCs increased before and after the treatment with liniment levamisole. CONCLUSION: Liniment levamisole may reinforce cellular immune functions of patients with chronic hepatitis B.

Adjuvants, Immunologic↗

PubMed2005

Characterization of molecular defect of 13387-9delG mutated antithrombin in inherited type I antithrombin deficiency.

As a major physiological inhibitor of thrombin and other coagulation proteases, antithrombin (AT) plays an important role in the maintenance of normal hemostasis and its deficiency is associated with a predisposition for familial venous thromboembolic disease. Recently, we found a novel mutation (13387-9delG) in the antithrombin gene that is associated with type I AT deficiency. To examine the molecular pathologic mechanism of this mutation causing type I AT deficiency, the wild-type and the mutant AT constructs were expressed in COS-7 cells or Chinese Hamster Ovary cells. No AT antigen could be detected by enzyme-linked immunosorbent assay in the conditioned media of cells expressing the mutant protein, and the AT antigen level was reduced in cell lysates. The mutant AT-expressing cells did not have less intracellular mRNA levels than the wild-type transfectants as estimated by quantitative reverse transcriptase-polymerase chain reaction. Metabolic and pulse-chase experiments showed the newly synthesized wild-type AT protein was gradually secreted into the media, whereas no labeled mutant AT protein was detected in the media and the total amount of radioactivity was significantly reduced in the cells during the chase periods. By immunofluorescence analysis, the staining of the mutant AT was weaker than that of the wild type, and was predominantly diffuse without perinuclear enhancement. These results indicate that the 13387-9delG mutation, which disrupts the disulfide bridge Cys247-Cys430, impairs the secretion and stability of the truncated AT protein associated with intracellular degradation.

Adolescent↗

PubMed2005

Molecular mechanisms of antithrombin deficiency in two Chinese families. One novel and one recurrent point mutation in the antithrombin gene causing venous thrombosis.

We investigated the molecular mechanisms responsible for type I congenital antithrombin (AT) deficiency in two unrelated Chinese pedigrees manifesting multiple site venous thrombosis. Phenotype analysis showed both probands had almost 50% of normal AT levels. Direct sequencing of amplified DNA revealed 2757C > T in proband 1 and 13328G > A in proband 2, predicting a heterozygous Thr98Ile (T981) and Ala404Thr (A404T), respectively. No proband had 20210A allele or factor V Leiden mutation. Transient expression of complementary DNA coding for the mutations in COS-7 cells showed impaired secretion of the mutant molecules. Real-time quantitative PCR indicated that the mutant AT mRNA was transcribed at a similar or even higher level as that of wild-type (wt). Pulse-chase labeling studies suggested both AT variants did not accumulate, but degraded intracellularly. Immunohistochemical staining of the transfected cells revealed that CHO cells expressing the AT-198 mutant were stained diffusely without perinuclear enhancement and cells expressing AT-T404 mutant mainly in the whole cytoplasm with weaker perinuclear enhancement. We conclude that the impaired secretion of the mutant AT molecules, due to intracellular degradation, is the molecular pathogenesis of AT deficiency caused by T981 and A404T mutation for the two families, respectively.

Animals↗

PubMed2005

Altered gene expression of angiogenic factors induced by calcium-mediated dissociation of retinal pigment epithelial cells.

PURPOSE: To examine the effect of loss of cell-cell contacts on the gene expression of vascular endothelial growth factor (VEGF) and other factors in primary culture of human retinal pigment epithelial (RPE) cells with real-time reverse transcription-PCR. METHODS: The dissociation of postconfluent RPE cells was induced by calcium chelation, low-calcium medium, anti-E-cadherin, and anti-N-cadherin antibodies. Total RNA was isolated from the cultured RPE cells and reverse transcribed to cDNA. VEGF was quantified by real-time PCR with a fluorescence detector. VEGF isoforms were differentially measured by specific exon-spanning primers. Besides VEGF, the gene expression levels of some other growth factors were also examined in calcium-mediated dissociation. RESULTS: Disruption of cell-cell contacts of RPE cells was induced by calcium chelation and low-calcium medium, but not by anti-E-cadherin and anti-N-cadherin antibodies. Calcium-mediated dissociation of RPE cells significantly increased the gene expression levels of VEGF. The mRNA levels of VEGF increased by 6.3-fold on treatment with EGTA and by 4.7-fold in the low-calcium medium at 6 hours. Splice variants of VEGF showed the differential pattern of gene expression. Whereas the expression of VEGF(121) and VEGF(165) was upregulated on calcium-induced dissociation of RPE cells, that of VEGF(145) and VEGF(189) was unchanged. VEGF(206) was not detected. On calcium-induced dissociation, bFGF, IL-6, matrix metalloproteinase (MMP)-1, and placental growth factor (PlGF) were upregulated, whereas acidic (a)FGF and pigment epithelium-derived factor (PEDF) were both downregulated. CONCLUSIONS: The results show that loss of intercellular contacts promotes increased gene expression of VEGF and other angiogenic factors in human RPE cells.

Actins↗

PubMed2005

[The inherited coagulation factor XI deficiency caused by intronic mutation IVS J-4delgttg].

OBJECTIVE: To identify gene defect in a Chinese pedigree of hereditary coagulation factor XI (FXI) deficiency. METHODS: The peripheral blood samples were collected from the proband and her family members. The plasma PT, APTT, FXI:C and FXI:Ag were assayed. The FXI gene exons and exon-intron boundaries of the proband were amplified by PCR and then sequenced directly. The mRNA of FXI in the peripheral blood was analyzed with RT-PCR. RESULTS: The proband and some of her family members had prolonged APTT. The plasma FXI:C and FXI:Ag of the proband, her brother and her parents were lower than 10% and 50% of the normal values, respectively. Nucleotide sequence analysis revealed that the proband and her brother had a homozygous mutation of IVS J-4delgttg in FXI gene. The mutation was inherited from her parents who were heterozygotes. The mutation was not found in 60 normal subjects. No FXI mRNA was detected in peripheral blood sample of the proband. CONCLUSION: The IVS J-4delgttg is a novel mutation causing FXI deficiency, which may interfere with mRNA splicing.

Adult↗

PubMed2005

Comparative study on cerebral injury after open heart surgery in patients with congenital and rheumatic heart disease.

OBJECTIVE: To comparatively study the different effects of open heart surgery on brain tissues of patients with congenital and rheumatic heart disease. METHODS: Forty patients with congenital heart disease (CHD, CHD group, n = 20) or rheumatic heart disease (RHD, RHD group, n = 20) underwent on-pump (cardiopulmonary bypass, CPB) heart-beating open heart surgery. Blood samples before CPB, and 20 minutes, 1 hour, 24 hours and 7 days after CPB were collected, and the levels of neuron-specific enolase (NSE) and protein S-100b in the plasma were determined with enzyme-linked immunoadsorbent assay (ELISA), respectively. All the patients were examined with electroencephalogram (EEG) before and 1 week after operation. The changes of NSE, S-100b and EEG compared to verify the difference of postoperative cerebral injury between CHD cases and RHD cases. RESULTS: The plasma level of S-100b increased significantly 20 minutes after CPB and was still higher than the preoperative level at 24 hours after operation in both groups (P < 0.01). The plasma level of NSE increased more significantly in the CHD group than in the RHD group 20 minutes after CPB and it returned to the normal level 24 hours after CPB in the CHD group but remained at a high level in the RHD group (P < 0.01). The levels of NSE and S-100b returned to the normal levels on the 7th day after CPB. Abnormal EEG was found in 75% of the patients in the CHD group and 60% in the RHD group. CONCLUSIONS: On-pump heart-beating open heart surgery can cause certain cerebral injury in the patients with CHD or RHD. The injury was more severe and recovered more quickly in the CHD group than in the RHD group.

Cardiac Surgical Procedures↗

PubMed2005

Factor X Shanghai and disruption of translocation to the endoplasmic reticulum.

BACKGROUND AND OBJECTIVES: Most secreted proteins, including coagulation factor X (FX), are synthesized with a signal peptide, which is necessary for targeting the nascent polypeptide into the endoplasmic reticulum. Characterization of naturally occurring mutations may provide insights into the functional roles of the amino acids in the signal peptide. DESIGN AND METHODS: A 52-year old male patient with type I FX deficiency was studied. Mutations were searched for by FX gene (F10) sequencing. The wild-type and the mutant FX proteins were expressed in transfected cells and then immunological assays were performed. Pulse-chase experiments and cell-free expression studies were conducted to determine the cellular fate of the mutant FX molecules. RESULTS: The patient we studied was homozygous for a substitution of arginine for serine at codon -30 in the signal sequence of F10. Immunoassays detected low FX antigen levels in both the conditioned media and lysates of the cells expressing the mutant protein. Pulse-chase analysis showed that only trace amounts of the mutant FX protein were detectable in the conditioned media, and that the mutant molecules did not accumulate inside the cells either. The results of cell-free expression studies showed that although the transcription and translation of the mutant construct were normal, no post-translational processing, such as N-linked glycosylation, occurred in the presence of microsomes. INTERPRETATION AND CONCLUSIONS: These findings suggest that substitution of a neutral polar amino acid, serine by arginine, in the hydrophobic core of FX signal peptide severely impairs the ability of the protein to enter the endoplasmic reticulum and results in FX deficiency.

Amino Acid Substitution↗

PubMed2005

[Inherited afibrinogenemia caused by compound heterozygous mutations in the beta beta-chain of fibrinogen].

Congenital afibrinogenemia is a rare autosomal recessive disorder, characterized by the complete absence or extremely reduced level of fibrinogen. To analyze the phenotype and genotype of a family with inherited afibrinogenemia, laboratory studies including activated partial thromboplastin time (APTT), prothrombin time (PT) and thrombin time (TT) were tested in the proband and 9 family members. Fibrinogen (Fg) in plasma were measured by both functional and immunoturbidimetry assay. All the exons, exon-intron boundaries and promoter regions of three Fg genes were analyzed by direct sequencing. 102 healthy blood donors were used as normal control. The results showed that phenotype of the proband was diagnosed as afibrinogenemia. Compound heterozygous mutations in Fg FGB gene were detected in the proband. One was a nonsense mutation (Arg17stop) in exon 2, traced back to the proband's mother. The other was a missense mutation (Gly347Arg) in exon 7, which was from the proband' s father. It is concluded that afibrinogenemia is caused by the compound heterozygous mutations Arg17stop and Gly347Arg in the Beta beta-chain of fibrinogen.

Adult↗

PubMed2004

Cloning and sequencing of cagA gene fragment of Helicobacter pylori with coccoid form.

AIM: To clone and sequence the cagA gene fragment of Helicobacter pylori (H pylori) with coccoid form. METHODS: H pylori strain NCTC11637 were transformed to coccoid form by exposure to antibiotics in subinhibitory concentrations. The coccoid H pylori was collected. cagA gene of the coccoid H pylori strain was amplified by PCR. After purified, the target fragment was cloned into plasmid pMD-18T. The recombinant plasmid pMD-18T-cagA was transformed into E.coli JM109. Positive clones were screened and identified by PCR and digestion with restriction endonucleases. The sequence of inserted fragment was then analysed. RESULTS: cagA gene of 3,444 bp was obtained from the coccoid H pylori genome DNA. The recombinant plasmid pMD-18T-cagA was constructed, then it was digested by BamH I+Sac I, and the product of digestion was identical with the predicted one. Sequence analysis showed that the homology of coccoid and the reported original sequence H pylori was 99.7%. CONCLUSION: The recombinant plasmid containing cagA gene from coccoid H pylori has been constructed successfully. The coccoid H pylori contain completed cagA gene, which may be related to pathogenicity of them.

Antigens, Bacterial↗

PubMed2004

Simultaneously multi-parameter determination of hematonosis cell apoptosis by two-photon and confocal laser scanning microscopy.

Flow cytometry (FCM), TdT-mediated dUTP Nick End Labeling (TUNEL), and DNA ladder are conventional methods to detect apoptosis of drug-treated cells. However, the assumption of cell number restricts their applications in clinics. In this paper, we report a cell-saving imaging method for quick identification of the hematonosis cell apoptosis induced by chemotherapeutic drugs. By the combination of two-photon and confocal microscopy, three main apoptosis parameters (the change of nuclear morphology, collapse of mitochondrial membrane potential, and increase of intracellular calcium) were recorded simultaneously for single As2O3-induced Molt-4 cells. The results are highly in accordance with those produced by classical flow cytometry. This work suggests that this new imaging method would be promising in the quick identification of hematonosis cell apoptosis.

Apoptosis↗

PubMed2004

Differential gene expression of early and late passage retinal pigment epithelial cells.

We examined the gene expression profiles of retinal pigment epithelial (RPE) cells which were aged in vitro by repeated passage. RPE cells from human eyes were cultured to passage 3-5 (early passage) or 19-21 (late passage) and used to study gene expression profiles by cDNA microarray. Results from microarray analysis were further confirmed by real-time PCR. Microarray analysis showed gene expression changes among 588 known genes. The expression levels of 15 genes (2.6%) increased in late passage RPE cells, while 43 genes (7.3%) decreased using a two-fold criterion. These differentially expressed genes encompassed many functional classes. A small number of stress genes, such as clusterin, replication protein A and Ku80, were up-regulated. The down-regulated genes included many enzymes of energy and biomolecule metabolism as well as cell cycle proteins and cell adhesion proteins. Results from real-time PCR were generally consistent with microarray findings. The expression levels of the examined angiogenic factors were either unchanged or down-regulated. Comparing early (p=3-5) and late (p=9-12) passage RPE cells, several categories of differentially expressed genes were identified. However, there was no enhanced expression of known angiogenic factors.

Angiogenesis Inducing Agents↗

PubMed2004

LTP and LTD vary with layer in rodent visual cortex.

Mechanisms of plasticity in the visual cortex have been studied with long-term potentiation (LTP), long-term depression (LTD) and ocular dominance plasticity (ODP). It is now possible to compare results from these three forms of plasticity using knockout mice, and also by pharmacological manipulations. A review of the literature shows that if both LTP and LTD are completely abolished, then ODP will also be abolished. In other situations, there is little correlation. We hypothesize that this lack of correlation occurs because the mechanisms for LTP and LTD vary with layer in the visual cortex, and results show that they do.

Animals↗