Biomedical subjects

Kun Wang

Publications and source records attributed to Kun Wang.

At least 55 records · Page 3Linked to original sources

PubMed2005

A novel glucose biosensor based on the nanoscaled cobalt phthalocyanine-glucose oxidase biocomposite.

We report on the utilization of a novel nanoscaled cobalt phthalocyanine (NanoCoPc)-glucose oxidase (GOD) biocomposite colloid to create a highly responsive glucose biosensor. The biocomposite colloid is constructed under enzyme-friendly conditions by adsorbing GOD molecules on CoPc nanoparticles via electrostatic interactions. The glucose biosensor can be easily achieved by casting the biocomposite colloid on a pyrolytic graphite electrode (PGE) without any auxiliary matter. It has been found that GOD can be firmly immobilized on PGE surface and maintain its bioactivity after conjugating with NanoCoPc. NanoCoPc displays intrinsic electrocatalytic ability to the oxidation of the product of enzymatic reaction H2O2 and shows a higher catalytic activity than that of bulk CoPc. Under optimal conditions, the biosensor shows a wide linear response to glucose in the range of 0.02-18 mM, with a fast response (5s), high sensitivity (7.71 microA cm(-2) mM(-1)), as well as good thermostability and long-term life. The detection limit was 5 microM at 3 sigma. The general interferences coexisted in blood except ascorbic acid and L-cysteine do not affect glucose determination, and further coating Nafion film on the surface of the biosensor can effectively eliminate the interference from ascorbic acid and L-cysteine. The biosensor with Nafion film has been used for the determination of glucose in serum with an acceptable accuracy.

Biosensing Techniques↗

PubMed2005

The pharmacokinetics of a novel anti-tumor agent, beta-elemene, in Sprague-Dawley rats.

beta-Elemene, a natural sesquiterpene, is a novel anti-tumor agent. The pharmacokinetics of beta-elemene after single i.v. administration have been investigated in male SD rats. beta-Elemene was administered at three doses (50, 75 and 100 mg/kg) and a full pharmacokinetic profile was obtained. beta-Elemene was metabolized extensively and eliminated rapidly. High permeability of beta-elemene through the blood-brain barrier was found following i.v. administration based on the brain/plasma ratio. Following i.v. administration, the drug was eliminated primarily as metabolite and minimally as unchanged drug. Cumulative fecal, biliary and urinary excretion of beta-elemene in rats was 0.61%, 0.06% and 0.003% of the administered dose (75 mg/kg) at 32 h after administration, respectively. These results indicate that biotransformation may be the main elimination passage of beta-elemene. The metabolism of beta-elemene was extensive and the structure of the metabolite (M1) in rat bile was determined by GS/MS and NMR analysis.

Animals↗

PubMed2005

Association of the -183 polymorphism in the IFN-gamma gene promoter with hepatitis B virus infection in the Chinese population.

Interferon-gamma (IFN-gamma) is a pleiotropic cytokine that plays an important role in regulating cellular immune responses. Regulation of IFN-gamma expression is considered to be strictly controlled at the transcriptional level. Two single-nucleotide polymorphisms (SNPs) within the human IFN-gamma promoter (at positions -183 and -155) are considered to influence the promoter activity by altering the acting transcription factor-1 (AP-1) binding. We sought to assess the association between the SNPs of the IFN-gamma promoter and the host susceptibility to hepatitis B virus (HBV) infection, as well as its interaction with age and gender. No polymorphism at position-155 was detected in any of the participants, but a significant difference was found in the polymorphism at position -183 between the cases and controls (G/T and T/T vs. GG; P < 0.01, odds ratio (OR) = 4.50 (95% confidence interval (CI) = 2.23-9.09). A susceptibility analysis revealed a gradually increased trend of the OR value from the young to the old group (OR = 3.03, 4.17, and 5.56). Similarly, the association of the -183 polymorphism was markedly different in females (OR = 5.71). Our data suggest that the polymorphism at position -183 of the IFN-gamma gene promoter may be associated with susceptibility to HBV infection, and age and gender factors are coordinative risk factors.

Adult↗

PubMed2005

The human plasma proteome: analysis of Chinese serum using shotgun strategy.

We have investigated the serum proteome of Han-nationality Chinese by using shotgun strategy. A complete proteomics analysis was performed on two reference specimens from a total of 20 healthy donors, in which each sample was made from ten-pooled male or female serum, respectively. The methodology used encompassed (1) removal of six high-abundant proteins; (2) tryptic digestion of low- and high-abundant proteins of serum; (3) separation of peptide mixture by RP-HPLC followed by ESI-MS/MS identification. A total of 944 nonredundant proteins were identified under a stringent filter condition (X(corr) > or = 1.9, > or = 2.2, and > or = 3.75, < or = C(n) > or = 0.1, and R(sp) > or = 4.0) in both pooled male and female samples, in which 594 and 622 entire proteins were found, respectively. Compared with the total 3020 protein identifications confirmed by more than one laboratory or more than one specimen in HUPO Plasma Proteome Project (PPP) participating laboratories recently, 206 proteins were identified with at least two distinct peptides per protein and 185 proteins were considered as high-confidence identification. Moreover, some lower abundance serum proteins (ng/mL range) were detected, such as complement C5 and CA125, routinely used as an ovarian cancer marker in plasma and serum. The resulting nonredundant list of serum proteins would add significant information to the knowledge base of human plasma proteome and facilitate disease markers discovery.

Biomarkers↗

PubMed2005

[Comparison of esophageal acid exposure characteristics between reflux oesophagitis and non-erosive reflux diseases].

OBJECTIVES: Comparing the esophageal acid exposure characteristics between reflux oesophagitis (RE) and non-erosive reflux disease (NERD) patients to identify the NERD subgroups. METHODS: One hundred and twenty-eight patients with heartburn and acid regurgitation were evaluated. Esophageal mucosa injury was assessed by gastroscopy. The extent of esophageal acid exposure was determined by ambulatory 24 h esophageal pH monitoring. DeMeester point >/= 15 was taken as positive. RESULTS: Thirty-seven patients were found to have RE (28.9%), 91 were diagnosed as NERD. There was no difference at DeMeester point between RE and NERD (P > 0.05). Patients with RE have more long reflux episodes than NERD patients (8.16 +/- 10.27 vs 3.96 +/- 6.87; P = 0.004). Among NERD patients, 46 (50.5%) had an abnormal pH monitoring (NERD+); another 45 were normal (NERD-). Patients with NERD+ were more likely to demonstrate at positive symptom index (SI > 50%) than those with NERD- (43.5% vs 15.6%; P < 0.001). In NERD- group, patients with a positive SI (NERD-SI+) have more reflux episodes than those with a negative SI (NERD-SI-) (55.29 +/- 24.68 vs 34.87 +/- 24.06; P < 0.05), as well as the fraction time of 24 h that pH < 4 in upright (4.16 +/- 2.98 vs 1.88 +/- 1.60; P < 0.05). Twenty-five RE patients have an abnormal pH monitoring (RE+, 67.6%), another 12 were normal (RE-). RE- patients have a higher median of intra-esophageal and gastric pH than RE+ patients respectively (6.75 +/- 0.42 vs 5.18 +/- 1.32; 2.69 +/- 2.59 vs 1.49 +/- 0.66; P < 0.05). CONCLUSIONS: RE patients have longer reflux episodes than NERD. The symptoms of most gastroesophageal reflux disease patients associate with acid reflux. Acid reflux characteristics and symptom patterns suggest subgroups of NERD patients. The bile or mixed reflux may be involved in the pathogenesis of RE- group.

Adolescent↗

PubMed2005

[Excretion of beta-elemene from rat respiratory tracts].

AIM: To investigate the excretion of beta-elemene from the respiratory tracts in male Spraque-Dawley rats. METHODS: After a single administration of beta-elemene to rats at the dosage of 75 mg x kg(-1) (i.v. or i.p.), the exhaled gases were collected and concentrated at various time points. The residues were analyzed by gas chromatography. RESULTS: A minor amount of unchanged beta-elemene was excreted via rat respiratory tracts after iv and ip administration of a single dose. The cumulative excretion were 1.41% and 0.51% respectively. CONCLUSION: The results demonstrated that unchanged beta-elemene excretes from rat respiratory tracts, but may not be the main elimination pathway in rats.

Animals↗

PubMed2005

[Sequences and their polymorphisms of swine MHC-DQB, DRB proximal promoter region].

The primers, RF/RR and QF1/QR,were designed based on the homologous region of swine MHC-DQB and DRB exon1 sequences and HLA-DQB and HLA-DRB sequences. The 5' proximal promoter region (URR) nucleotide sequences of swine MHC-DQB and DRB were firstly obtained by PCR, cloning and sequencing techniques. There exist highly conserved sequence motifs including W, X, Y, CCAAT, and TATA-like boxes in the obtained sequences,showing the same organization of the conserved regulatory elements as in other species. 12 DRB-URR and 14 DQB-URR alleles were found by PCR-SSCP in 313 pigs. The aligned results of these alleles showed that there exist abundant polymorphism sites in both Porcine MHC-DQB and DRB proximal promoter region.

Alleles↗

PubMed2005

[The changes of gastric diseases during the past twenty five years].

OBJECTIVES: To study the changes of duodenal ulcer, gastric ulcer, gastric cancer and Helicobacter pylori (Hp) infectious status, according to the clinical data of endoscopy in our hospital during the past 25 years. METHODS: The patients with duodenal ulcer, gastric ulcer and gastric cancer diagnosed by endoscopy and pathology had been selected, 104 987 general endoscope cases during the period from Jan. 1980 to Dec. 2004. The general cases were divided into 8 age groups as follows: 10-< 20 years old, 20-< 30 years old, 30-< 40 years old, 40-< 50 years old, 50-< 60 years old, 60-< 70 years old, 70-< 80 years old and > or = 80 years old. RESULTS: The average detected rate of duodenal ulcer, gastric ulcer, and gastric cancer are 13.03%, 4.19% and 1.68% respectively. The detected rate of gastric ulcer was decreased after 1996. The detected rate of duodenal ulcer was decreased after 1999. The gastric cancer detected rate fluctuate between 1.02% and 2.36%. The average ages of duodenal ulcer, gastric ulcer and gastric cancer are 41.8, 50.7 and 59.4 respectively. The tendency of average age shows ascendant. In all patients, the detected rate of Hp showed slightly descendent after 1999. CONCLUSIONS: The diagnostic age of duodenal ulcer, gastric ulcer and gastric cancer shows ascendant tendency; The detected rates of duodenal ulcer, gastric ulcer show descendent tendency; There is no apparent change in the detected rate of gastric cancer. The Hp detected rate shows descendent tendency slightly.

Adolescent↗

PubMed2005

[Genomic DNA sequences and functional expression, purification of BmalphaTX14 neurotoxin from scorpion Buthus martensii Karsch].

Based on the full-length cDNA of BmalphaTX14 from Chinese scorpion Buthus martensii Karsch (BmK), gene of the mature peptide of BmalphaTX14 was cloned into the yeast expression vector pPIC9K. After transforming, screening and inducing, tricine-SDS-PAGE and Western blot proved that rBmalphaTX14 protein was expressed in the medium for up to 84 hours, getting nearly 120 mg/L. Recombinant BmalphaTX14 was purified rapidly and efficiently through Ni-NTA-agarose, polyethylene glycol precipitation and gel filtration chromatography. The purified rBmalphaTX14 proved to have the anti-insect activity by toxicity assay. Meanwhile, genomic gene of BmalphaTX14 was cloned and sequenced by PCR method, sequence analysis of this gene showed that BmalphaTX14 had an intron of 408 base pairs located at the signal peptide encoding region, which was similar with the characteristic of other alpha-type sodium ion-channel toxin. Considering both the genomic organization and the peptide function, BmaTX14 proved to be a membership belonging to alpha-type sodium ion-channel toxin.

Amino Acid Sequence↗

PubMed2004

[Relationship between overexpression of facilitative glucose transporter-1 and fluorodeoxyglucose uptake in primary human lung adenocarcinoma].

OBJECTIVE: To assess the relationship between the overexpression of facilitative glucose transporter-1 (Glut1) and fluorine-18 fluorodeoxyglucose (FDG) uptake in patients with primary lung adenocarcinoma. METHODS: From April 1999 to March 2001, 24 patients with lung adenocarcinoma were imaged with FDG positron emission tomography (PET) before surgery. Their maximum and mean standard uptake value (SUVmax and SUVmean) of tumor and SUV of normal lung (SUVlung) were measured. The expression of Glut1 of all 24 cases was studied in paraffin sections by SP immunohistochemistry. RESULTS: All 23 tumors tested were Glut1 positive. (35 +/- 23)% of tumor cell area was positive and staining intensity was (3.7 +/- 0.9). All tumors of the patients could be detected by FDG-PET. FDG uptake of tumor was higher than that of normal lung (P < 0.01). SUVmax, SUVmean and SUVlung were (5.46 +/- 3.32), (4.05 +/- 2.54) and (0.43 +/- 0.15) respectively. Correlations were found among Glut1 expression and FDG uptake and tumor size (P < 0.01). CONCLUSION: Glut1 overexpression is universal in the lung adenocarcinoma and correlate with FDG uptake.

Adenocarcinoma↗

PubMed2004

Infusion of epidermal growth factor and basic fibroblast growth factor into the striatum of parkinsonian rats leads to in vitro proliferation and differentiation of adult neural progenitor cells.

This study investigated the proliferation and differentiation of adult neural progenitor cells (aNPCs) derived from the striatum and substantia nigra (SN) of parkinsonian rats. We found that aNPCs isolated from the two areas of parkinsonian rats readily formed nestin-enriched neurospheres in vitro and exhibited an ability to differentiate into either neurons or astrocytes. Injection of epidermal growth factor (EGF) and basic fibroblast growth factor (bFGF) into the striatum of parkinsonian rats prior to the harvesting striatal aNPCs significantly increased the neurosphere formation rate and multiple differentiation capacity of these aNPCs when cultured in vitro. These data suggest that striatal and nigral adult NPCs in parkinsonian rats retain the abilities of proliferation and differentiation in vitro. In addition, exogenously applied growth factors could up-regulate the developmental potential of aNPCs. We conclude that our data supports the notion that endogenous cell replacement therapies may be useful for the future treatment of Parkinson's disease (PD).

Animals↗

PubMed2004

Protein analysis with tetra-substituted sulfonated cobalt phthalocyanine by the technique of Rayleigh light scattering.

This is the first report of cobalt-tetrasulfonatophthalocyanine (CoTSPc) as a probe of Rayleigh light scattering (RLS) to determine proteins at nanogram levels. A highly sensitive method has been developed for the determination of proteins by the light scattering technique on a common spectrofluorimeter, based on the fact that the weak RLS of CoTSPc can be greatly enhanced in the presence of proteins. Under optimum conditions, the linear ranges of the calibration curves were 0.10-34.3 microg x mL(-1) for both human serum albumin and bovine serum albumin, with detection limits of 15.5 and 13.9 ng x mL(-1), respectively. Moreover, there is almost no interference of any amino acids and metal ions. The method has been applied to the direct determination of total proteins in human serum samples, and the results were satisfactory with clinical data provided.

Alkanesulfonates↗

PubMed2004

[The abnormity and clinical value of tyrosine kinase signaling pathway in lung adenocarcinoma].

OBJECTIVE: To study the abnormity and clinical value of tyrosine kinase signaling pathway in lung adenocarcinoma. METHODS: Total RNA was extracted form 10 lung adenocarcinoma samples and matched normal tissues. cDNA was labeled fluorescence during reverse transcription and hybridized on 20 slides of microarray with 13 824 genes. After washed and scanned, the cy3:cy5 ratios were obtained by computer analysis. Each experiment was repeated two times and the mean value was chosen. Cluster analysis and discriminant analysis were used to mine the pool data. The results were combined with clinical prognostic factors for further analysis. RESULTS: According to the abnormity of tyrosine kinase signaling pathway in lung adenocarcinoma, sample cluster divided the 10 samples into 3 groups and gene cluster divided all genes into 5 groups. Different prognosis samples had different characteristic genes. The patients with the best prognosis overexpressed some genes related to immunity and inhibition proliferation, and those with the worst prognosis overexpressed some genes related to proliferation while the genes related to immunity and inhibition proliferation were expressed at a low level. CONCLUSION: There are 3 type abnormity of tyrosine kinase signaling pathway in lung adenocarcinoma that are related to different biological behavior and different prognosis.

Adenocarcinoma↗

PubMed2004

Forskolin cooperating with growth factor on generation of dopaminergic neurons from human fetal mesencephalic neural progenitor cells.

Forskolin was tested for its co-activating ability to enhance the function of fibroblast growth factor (FGF) 8 on dopaminergic (DAergic) differentiation from human fetal mesencephalic neural progenitor cells (NPCs). When NPCs were treated with FGF8 alone, the DAergic phenotype was expressed lightly. The addition of 10 microM forskolin increased the number of DAergic neurons, cooperating with 50 ng/ml FGF8. These cells produced neurotransmitter DA, which was measured by high-performance liquid chromatography. Reverse transcriptase-polymerase chain reaction analysis demonstrated that differentiated cells expressed DAergic development-relative genes tyrosine hydroxylase (TH), nuclear receptor-related factor 1 (Nurr1) and D2 receptor (D2R), indicating that matured DAergic neurons could be obtained under these present conditions. The results suggest that forskolin plus FGF8 may contribute to more efficient production of DAergic neurons from human-derived NPCs for therapy of neurodegenerative diseases.

Cell Differentiation↗

PubMed2004

Alterations in expression, proteolysis and intracellular localizations of clusterin in esophageal squamous cell carcinoma.

AIM: To investigate biogenesis and intracellular localizations of clusterin to elucidate the potential molecular mechanisms implicated in tumorigenesis of esophageal mucosa. METHODS: Semi-quantitative RT-PCR for multi-region alteration analysis, Western blot for different transcriptional forms and immunohistochemical staining for intracellular localizations of clusterin were carried out in both tissues and cell lines of ESCC. RESULTS: The N-terminal deletions of the clusterin gene and the appearance of a 50-53 ku nuclear clusterin, an uncleaved, nonglycosylated, and disulfide-linked isoform, were the major alterations in cancer cells of esophagus. Naturally the 40 ku clusterin was located in the connective tissue of the lamina propria of epithelial mucosa and right under the basal membrane of epithelia, but it was disappeared in stromal mucosa of esophagus and the pre-matured clusterin was found positive in cancerous epithelia. CONCLUSION: The N-terminal deletion of clusterin may be essential for its alterations of biogenesis in ESCC.

Carcinoma, Squamous Cell↗

PubMed2004

Overexpression of annexin 1 in pancreatic cancer and its clinical significance.

AIM: To investigate the expression of annexin I in pancreatic cancer and its relationship with the clinicopathologic factors, and to evaluate its potential clinical significance. METHODS: Annexin I expression was analyzed by Western blot and immunohistochemical staining in pancreatic adenocarcinoma and multi-tissue microarrays (MTAs). RESULTS: Western blot analysis showed that annexin I was overexpressed in 84.6% (11/13) pancreatic ductal adenocarcinomas. Immunohistochemistry analysis of pancreatic cancer in MTAs showed that annexin I protein was 71.4%(30/42) positive which was markedly increased compared with that in the tumor matched normal pancreas tissues 18.4%(7/38) (P<0.01). In the meantime, the high expression of annexin 1 was correlated with the poor differentiation of pancreatic adenocarcinoma. CONCLUSION: Annexin 1 overexpression is a frequent biological marker and correlates with the differentiation of pancreatic cancer during tumorigenesis.

Adenocarcinoma↗

PubMed2004

Distinct efficacy of pre-differentiated versus intact fetal mesencephalon-derived human neural progenitor cells in alleviating rat model of Parkinson's disease.

Neural progenitor cells have shown the effectiveness in the treatment of Parkinson's disease, but the therapeutic efficacy remains variable. One of important factors that determine the efficacy is the necessity of pre-differentiation of progenitor cells into dopaminergic neurons before transplantation. This study therefore investigated the therapeutic efficacy of mesencephalon-derived human neural progenitor cells with or without the pre-differentiation in alleviating a rat model of Parkinson's disease. We found that a combination of 50 ng/ml fibroblast growth factor 8, 10 ng/ml glial cell line-derived neurotrophic factor and 10 microM forskolin facilitated the differentiation of human fetal mesencephalic progenitor cells into dopaminergic neurons in vitro. More importantly, after transplanted into the striatum of parkinsonian rats, only pre-differentiated grafts resulted in an elevated production of dopamine in the transplanted site and the amelioration of behavioral impairments of the parkinsonian rats. Unlike pre-differentiated progenitors, grafted intact progenitors rarely differentiated into dopaminergic neurons in vivo and emigrated actively away from the transplanted site. These data demonstrates the importance of pre-differentiation of human progenitor cells before transplantation in enhancing therapeutic potency for Parkinson's disease.

3,4-Dihydroxyphenylacetic Acid↗

PubMed2004

Gaussian mapping of chemical fragments in ligand binding sites.

We present a new approach to automatically define a quasi-optimal minimal set of pharmacophoric points mapping the interaction properties of a user-defined ligand binding site. The method is based on a fitting algorithm where a grid of sampled interaction energies of the target protein with small chemical fragments in the binding site is approximated by a linear expansion of Gaussian functions. A heuristic approximation selects from this expansion the smallest possible set of Gaussians required to describe the interaction properties of the binding site within a prespecified accuracy. We have evaluated the performance of the approach by comparing the computed Gaussians with the positions of aromatic sites found in experimental protein-ligand complexes. For a set of 53 complexes, good correspondence is found in general. At a 95% significance level, approximately 65% of the predicted interaction points have an aromatic binding site within 1.5 A. We then studied the utility of these points in docking using the program DOCK. Short docking times, with an average of approximately 0.18 s per conformer, are obtained, while retaining, both for rigid and flexible docking, the ability to sample native-like binding modes for the ligand. An average 4-5-fold speed-up in docking times and a similar success rate is estimated with respect to the standard DOCK protocol.

Algorithms↗