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Biomedical subjects

Yi-Ming Wang

Publications and source records attributed to Yi-Ming Wang.

16 recordsLinked to original sources
PubMed2006

Hepatitis C virus NS4A inhibits cap-dependent and the viral IRES-mediated translation through interacting with eukaryotic elongation factor 1A.

The genomic RNA of hepatitis C virus (HCV) encodes the viral polyprotein precursor that undergoes proteolytic cleavage into structural and nonstructural proteins by cellular and the viral NS3 and NS2-3 proteases. Nonstructural protein 4A (NS4A) is a cofactor of the NS3 serine protease and has been demonstrated to inhibit protein synthesis. In this study, GST pull-down assay was performed to examine potential cellular factors that interact with the NS4A protein and are involved in the pathogenesis of HCV. A trypsin digestion followed by LC-MS/MS analysis revealed that one of the GST-NS4A-interacting proteins to be eukaryotic elongation factor 1A (eEF1A). Both the N-terminal domain of NS4A from amino acid residues 1-20, and the central domain from residues 21-34 interacted with eEF1A, but the central domain was the key player involved in the NS4A-mediated translation inhibition. NS4A(21-34) diminished both cap-dependent and HCV IRES-mediated translation in a dose-dependent manner. The translation inhibitory effect of NS4A(21-34) was relieved by the addition of purified recombinant eEF1A in an in vitro translation system. Taken together, NS4A inhibits host and viral translation through interacting with eEF1A, implying a possible mechanism by which NS4A is involved in the pathogenesis and chronic infection of HCV.

Amino Acid Sequence↗
PubMed2006

Cost-effectiveness analysis of colorectal cancer screening with stool DNA testing in intermediate-incidence countries.

BACKGROUND: The aim of this study is to compare the cost-effectiveness of screening with stool DNA testing with that of screening with other tools (annual fecal occult blood testing, flexible sigmoidoscopy every 5 years, and colonoscopy every 10 years) or not screening at all. METHODS: We developed a Markov model to evaluate the above screening strategies in the general population 50 to 75 years of age in Taiwan. Sensitivity analyses were performed to assess the influence of various parameters on the cost-effectiveness of screening. A third-party payer perspective was adopted and the cost of dollar 13,000 per life-year saved (which is roughly the per capita GNP of Taiwan in 2003) was chosen as the ceiling ratio for assessing whether the program is cost-effective. RESULTS: Stool DNA testing every three, five, and ten years can reduce colorectal cancer mortality by 22%, 15%, and 9%, respectively. The associated incremental costs were dollar 9,794, dollar 9,335, and dollar 7,717, per life-year saved when compared with no screening. Stool DNA testing strategies were the least cost-effective with the cost per stool DNA test, referral rate with diagnostic colonoscopy, prevalence of large adenoma, and discount rate being the most influential parameters. CONCLUSION: In countries with a low or intermediate incidence of colorectal cancer, stool DNA testing is less cost-effective than the other currently recommended strategies for population-based screening, particularly targeting at asymptomatic subjects.

Colonoscopy↗
PubMed2006

Interaction study between double-stranded DNA and berberine using capillary zone electrophoresis.

Two non-self-complementary 17-mer double-stranded DNA (dsDNA) with four different central base pairs were designed to systematically investigate the binding affinity and sequence specificity of berberine with dsDNA by capillary zone electrophoresis (CZE). The data analysis with the Kenndler model proved only low affinity between dsDNA and berberine and suggested some weak binding preference of berberine for AATT-containing to GGCC-containing dsDNA. The binding constant, Ka, between berberine and dsDNA(AB) was about (1.0 +/- 0.7) x 10(3) M(-1). In addition, the separation of single-stranded DNA (ssDNA) from dsDNA under simple electrophoretic conditions enabled CZE to be a potentially alternative tool to check the extent of DNA annealing, which is usually done by the time-consuming and labor-intensive slab electrophoresis.

Base Sequence↗
PubMed2006

Design of highly active binary catalyst systems for CO2/epoxide copolymerization: polymer selectivity, enantioselectivity, and stereochemistry control.

Asymmetric, regio- and stereoselective alternating copolymerization of CO(2) and racemic aliphatic epoxides proceeds effectively under mild temperature and pressure by using a binary catalyst system of a chiral tetradentate Schiff base cobalt complex [SalenCo(III)X] as the electrophile in conjunction with an ionic organic ammonium salt or a sterically hindered strong organic base as the nucleophile. The substituent groups on the aromatic rings, chiral diamine backbone, and axial X group of the electrophile, as well as the nucleophilicity, leaving ability, and coordination ability of the nucleophile, all significantly affect the catalyst activity, polymer selectivity, enantioselectivity, and stereochemistry. A bulky chiral cyclohexenediimine backbone complex [SalcyCo(III)X] with an axial X group of poor leaving ability as the electrophile, combined with a bulky nuclephile with poor leaving ability and low coordination ability, is an ideal binary catalyst system for the copolymerization of CO(2) and a racemic aliphatic epoxide to selectively produce polycarbonates with relatively high enantioselectivity, >95% head-to-tail connectivity, and >99% carbonate linkages. A fast copolymerization of CO(2) and epoxides was observed when the concentration of the electrophile or/and the nucleophile was increased, and the number of polycarbonate chains was proportional to the concentration of the nucleophile. Electrospray ionization mass spectrometry, in combination with a kinetic study, showed that the copolymerization involved the coordination activation of the monomer by the electrophile and polymer chain growth predominately occurring in the nucleophile. Both the enantiomorphic site effect resulting from the chiral electrophile and the polymer chain end effect mainly from the bulky nucleophile cooperatively control the stereochemistry of the CO(2)/epoxide copolymerization.

Journal Article↗
PubMed2006

Effect of 5-azacytidine on the protein expression of porcine bone marrow mesenchymal stem cells in vitro.

Bone marrow-derived mesenchymal stem cells (MSCs) are pluripotent stem cells that show a vital potential in the clinical application for cell transplantation. In the present paper, proteomic techniques were used to approach the protein profiles associated with porcine bone marrow MSCs and investigate the regulation of MSC proteins on the effect of 5-azacytidine (5-aza). Over 1,700 protein species were separated from MSCs according to gel analysis. Compared with the expression profiling of control MSCs, there were 11 protein spots up-regulated and 26 down-regulated in the protein pattern of 5-aza-treated cells. A total of 21 proteins were successfully identified by MALDI-TOF-MS analysis, among which some interesting proteins, such as alpha B-crystallin, annexin A2, and stathmin 1, had been reported to involve in cell proliferation and differentiation through different signaling pathways. Our data should be useful for the future study of MSC differentiation and apoptosis.

Animals↗
PubMed2006

Proteomic profiling of rat bone marrow mesenchymal stem cells induced by 5-azacytidine.

Mesenchymal stem cells (MSCs) can differentiate into different types of cells and thus have tremendous potential for cell therapy and tissue engineering. 5-Azacytidine (5-aza), a DNA demethylation reagent, has been reported to induce MSCs to differentiate into cardiomyocytes in vitro. To determine a global effect of 5-aza on MSCs, we investigated the protein expressions of rat MSCs with two-dimensional gel electrophoresis (2-DE). We have generated a proteome reference map of rat MSCs, and have successfully identified 34 proteins with MALDI-TOF-MS analysis. Nine proteins showed distinct regulation in MSCs after 5-aza treatment. The proteins regulated by 5-aza included cytoskeletal proteins, cadmium-binding proteins, and metabolic proteins, etc. These proteins have been reported to be involved in cell proliferation and differentiation through different signaling pathways, and the molecular mechanism of MSCs differentiation is discussed at the proteome level.

Animals↗
PubMed2005

An approach to develop two-dimensional fingerprint for the quality control of Qingkailing injection by high-performance liquid chromatography with diode array detection.

An approach was proposed to develop two-dimensional fingerprint (2D fingerprint) by means of principal component analysis (PCA) of high-performance liquid chromatography with diode array detection (HPLC/DAD) data. The approach was applied to establish 2D fingerprints of various Qingkailing injections which were produced by different manufacturers and procedures. In comparison with common one-dimensional fingerprint (ID fingerprint) at fixed wavelength, 2D fingerprint compiled additional spectral data and was hence more informative. Principal component analysis of the 2D fingerprint data was performed in this study, and it led to an accurate classification of various samples on their manufacturers and procedures. The quality of Qingkailing samples was further evaluated by similarity measures and the same results were achieved. For comparison, four conventional ID fingerprints were also applied to the quality assessment for the same samples. Finally, we demonstrated that 2D fingerprint was a more powerful tool to characterize the quality of samples, and could be used to comprehensively conduct the quality control of traditional Chinese medicines.

Chromatography, High Pressure Liquid↗
PubMed2005

Simultaneous determination of major bioactive components in Qingkailing injection by high-performance liquid chromatography with evaporative light scattering detection.

High-performance liquid chromatography with evaporative light scattering detection (HPLC/ELSD) was established for simultaneous determination of seven major bioactive components of Qingkailing injection including adenosine, geniposide, chlorogenic acid, baicalin, ursodeoxycholic acid, cholic acid, and hyodeoxycholic acid. The proposed method was applied to analyze ten various Qingkailing injections and produced data with acceptable linearity, repeatability, precision and accuracy having a limit of detection (LOD) of 10-50 ng. In comparison with UV detection, HPLC/ELSD permits the determination of non-chromophoric compounds without prior derivatization, and shows good compatibility to the multi-components of complex analytes. The proposed method is a useful alternative for routine analysis in the quality control of traditional Chinese medicine.

Chromatography, High Pressure Liquid↗
PubMed2005

[Application of HPLC/ELSD fingerprint and constellation graphical clustering method applied to evaluate the quality of Qingkailing injection].

AIM: To evaluate the quality of Qingkailing injections effectively, and to develop a credible method for the quality control of traditional Chinese medicine. METHODS: Fingerprints of 18 Qingkailing injection samples from various manufacturers were obtained by HPLC/ELSD, and quality evaluation was performed by constellation graphical clustering method. RESULTS: HPLC/ELSD and constellation graphical clustering method properly revealed the quality information apparently and accurately. CONCLUSION: It was an apparent, credible and efficient method for quality evaluation of Chinese medicines.

Chromatography, High Pressure Liquid↗
PubMed2005

[HPLC fingerprint for the Corydalis saxicola Bunting injection].

AIM: To establish the fingerprint of Corydalis saxicola Bunting injection. METHODS: It was performed by HPLC Kromasil column was used with acetonitrile and H2O as mobile phase. The flow rate was 0.5 mL x min(-1). The detection wavelength was 254 nm. The mass spectrometry detection was performed on a trap equipped with an ESI interface and operated in positive-ionization mode. RESULTS: Eleven components of Corydalis saxicola Bunting were identified by LC-MS and 7 of them were quantified. CONCLUSION: The fingerprint chromatogram could represent the characteristics of Corydalis saxicola Bunting injection. Evaluation of resemblances and results of precision were satisfactory. This method could be used as quality and quantity control.

Berberine↗
PubMed2005

[Comparison of treatment efficacy of the second and the third generations of chemoradiotherapy regimens containing platinum on advanced non-small cell lung cancer].

BACKGROUND & OBJECTIVE: Platinum-based chemotherapy regimens are better than other regimens when treating patients with advanced non-small cell lung cancer (NSCLC). The third generation of platinum-based regimens {NP [Navelbine (NVB), cisplatin (DDP)], TP (Taxol, DDP), GP (Gemzar, DDP)} is better than the second generation {MVP [mitomycin (MMC), desacetylvinblastin amide (VDS), DDP], MIP [MMC, ifosfamide (IFO), DDP], EP [etopside (VP-16), DDP], VDS+DDP}. This study was to compare the efficacy between the second and the third generations of platinum-based regimens combined with radiotherapy on advanced non-small cell lung cancer (NSCLC). METHODS: From Jul. 1999 to Dec. 2001, 47 pathologically confirmed advanced NSCLC patients received chemoradiotherapy: 24 received the second generation of platinum-based regimens, 23 received the third generation; all patients received routine external irradiation of (60)Co (65-76 Gy). Characteristics of the patients were comparable. Kaplan-Meier analysis was used to evaluate survival rates, and log-rank test to study differences between the 2 groups. RESULTS: The objective response rates were 41.7% in the second generation group, and 56.5% in the third generation group (Chi (2)=0.53, P=0.47). The median time to progression and median survival time were significantly longer in the third generation group than in the second generation group (12.6 months vs. 6.0 months, Chi(2)=6.93, P=0.01; 14.0 months vs. 9.0 months, Z=-2.17, P=0.03). The 1-, and 2-year survival rates were significantly higher in the third generation group than in the second generation group (56.3% vs. 30.7%, 15.6% vs. 0%, Chi(2)=6.59, P=0.01). The major adverse events were leukocytopenia, nausea and vomiting, radiation-induced esophagitis and pneumonia, which were tolerable. CONCLUSIONS: The third generation of platinum-based regimens in combination with radiotherapy for advanced non-small lung cancer may be more advantageous over the second generation of platinum-based regimens in prolonging survival of advanced NSCLC patients, which would be worth being studied further.

Adult↗
PubMed2005

[An in vitro study of cholesterol-lowering properties of probiotics isolated from the human feces].

21 strains of Lactobacillus and Bifidobacterium, isolated from feces of healthy youth and children feces and identified by molecular biological methods, together with 6 strains of probiotics preserved in Onlly lab were studied in the experiments, including removal cholesterol from media, bile-tolerance and acid-tolerance. The results demonstrated that all strains could remove cholesterol from media and removal rates of 5 strains were more than 40%. Meanwhile these 5 strains had high removal effectiveness. The bile-tolerance and acid-tolerance were varied from strain to strain. Among 27 strains, Bm26 demonstrated higher ability of removal cholesterol, bile-tolerance and bile-tolerance than other strains.

Adolescent↗
PubMed2003

Lidocaine: the optimal timing of intravenous administration in attenuation of increase of intraocular pressure during tracheal intubation.

BACKGROUND: This study was designed to examine the optimal timing of intravenous lidocaine in attenuation of increase of intraocular pressure in response to laryngoscopy and tracheal intubation during induction of anesthesia. METHODS: One hundred and thirty five adult patients of ASA class I, aged between 20-35 years, undergoing surgical procedures irrelevant to ophthalmology were enrolled for study. Patients were randomly assigned to one of five groups. In group II, III, IV and V the patients received intravenous injection of lidocaine (2 mg/kg), 1, 3, 5, 10 min before tracheal intubation, respectively. Group I in which patients did not receive lidocaine served as the control group. RESULTS: In patients of groups I, IV and V, the intraocular pressure increased significantly after intubation, whereas in those of groups II and III, the intraocular pressure did not. All patients in the five groups showed concomitantly a surge of blood pressure, but the magnitude of increase was smallest in group III in comparison with the other groups. The values of systolic and diastolic pressures 1 min after intubation were significantly less in groups III and IV than in the control group. CONCLUSIONS: In healthy patients aged between 20 and 35 the most optimal time of administration of intravenous lidocaine to attenuate the increase of intraocular pressure seemed to be the space between 1 to 3 min before laryngoscopy and tracheal intubation.

Adult↗
PubMed2002

Establishment of an interaction model of human apolipoprotein H with lipid monolayer by capillary SDS gel electrophoresis.

Apolipoprotein H (ApoH) is a plasma glycoprotein isolated from human serum. It plays a key role in the interaction with lipids. For the first time, the concentration of ApoH adsorbed on the lipid monolayer has been determined, and was done so using capillary electrophoresis. Based on this determination, an interaction model of ApoH and lipid monolayer was constructed, and this interaction is one of nonspecific adsorption. A neutral coated capillary (50 cm x 100 microm i.d.) and a negative voltage of 15 kV were used to separate ApoH. The calibration curve of ApoH was built using a detection limit of 50 microg/mL(-1) (near to 1 microM), and the RSD of the relative migration time of ApoH was 1.4% (n = 7).

Adsorption↗