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Biomedical subjects

W Y Wang

Publications and source records attributed to W Y Wang.

At least 19 recordsLinked to original sources
PubMed2001

Detection of Epstein-Barr virus DNA in the peripheral-blood cells of patients with nasopharyngeal carcinoma: relationship to distant metastasis and survival.

PURPOSE: Nasopharyngeal carcinoma (NPC) has been proved to be an Epstein-Barr virus (EBV)-associated cancer. By use of nested polymerase chain reactions (PCRs), we examined whether the presence of EBV DNA in the peripheral-blood cells (PBC) can serve as a prognostic indicator for NPC. PATIENTS AND METHODS: Peripheral blood from 124 patients with NPC who had no evidence of distant metastasis and 114 healthy volunteers with serologically positive findings for EBV infection was collected prospectively. Plasma and erythrocytes were separated. DNA was extracted from PBCs and analyzed by a nested PCR using primers specific to Epstein-Barr virus nuclear antigen 1 (EBNA-1). All patients were treated by radiotherapy with or without chemotherapy. Clinical parameters and status of EBNA-1 in PBCs were used for survival analysis using the Kaplan-Meier method and the Cox proportional hazards model. RESULTS: Positive rates of EBNA-1 DNA in PBCs of NPC patients and healthy volunteers are 71% and 14%, respectively (P =.001). No significant difference was observed with regard to the clinical characteristics of patients who were EBNA-1-positive (n = 88) and those who were EBNA-1-negative (n = 36). After a median follow-up period of 38 months (range, 24 to 56 months), 29 of 88 EBNA-1-positive patients and only one of 36 EBNA-1-negative patients developed distant metastases (P =.00015). Kaplan-Meier estimates of overall survival (P =.0010), metastasis-free survival (P =.0004), and progression-free survival (P =.0004) were significantly lower for the patients in the EBNA-1-positive group than for those in the EBNA-1-negative group. Multivariate Cox analysis confirmed the same results. CONCLUSION: The presence of EBNA-1 DNA in PBCs is a novel, important risk factor for patients with NPC that indicates a significantly higher risk of developing distant metastasis as well as a lower survival rate.

Adult↗
PubMed2001

Purification and characterization of jerdofibrase, a serine protease from the venom of Trimeresurus jerdonii snake.

A fibrin(ogen)olytic serine protease from Trimeresurus jerdonii venom was identified and purified to SDS-polyacrylamide gel electrophoresis homogeneity. It is a single chain polypeptide with a molecular weight of 32kDa under reduced condition and 28kDa under non-reduced condition, respectively. The venom protease catalysed the hydrolysis of some chromogenic substrates such as S2238, S2160, S2302 and S2251. It degraded Bbeta-chain of human fibrinogen preferentially. Also the enzyme degraded fibrin directly. Its enzymatic activity was completely inhibited by phenylmethylsulfonyl fluoride (PMSF), but not affected by EDTA. That suggested it was a serine protease. N-terminal sequence of the purified component showed high homology with other snake venom serine proteases.

Amino Acid Sequence↗
PubMed2001

Homocyclotirucallane and two dihydrophenanthrenes from Spiranthes sinensis.

A novel homocyclotirucallane, sinetirucallol (1), and two additional new dihydrophenanthrenes, sinensols G (2) and H (3), were isolated from the aerial parts of Spiranthes sinensis (Pers.) Ames. Their structures were determined by various spectral analyses, including MS and two-dimentional nuclear magnetic resonance techniques. The structure of compound 1 was further confirmed by single-crystal X-ray analysis. The absolute configuration of 1 was determined by modified Mosher's method.

Acetylation↗
PubMed2001

Efficacy trial of Vi polysaccharide vaccine against typhoid fever in south-western China.

OBJECTIVE: To test the efficacy of locally produced Vi vaccine over a time period of longer than one year. METHODS: A double-blinded, randomized field trial was performed in Guangxi Zhuang Autonomous Region in south-western China, using 30 micrograms doses of locally produced Vi. Enrolled subjects were 3-50 years of age, although the majority (92%) were school-aged children, who have the highest rate of typhoid fever in this setting. A total of 131,271 people were systematically allocated a single dose of 30 micrograms of Vi polysaccharide or saline placebo. The study population was followed for 19 months, with passive surveillance conducted in the Ministry of Health and the Regional Health and Anti-epidemic Centre (HAEC). Clinically suspected cases of typhoid fever were confirmed by blood culture, or by serological reaction with O-antigen (Widal tests). FINDINGS: After 19 months, there were 23 culture-confirmed cases of typhoid fever in the placebo group versus 7 cases in the Vi group (Protective efficacy (PE) = 69%; 95% CI = 28%, 87%). Most of the isolates were from school-aged children: 22 cases in the placebo group versus 6 in the Vi group (PE = 72%; 95% CI = 32%, 82%). No serious post-injection reactions were observed. The locally produced Vi polysaccharide vaccine showed levels of protective efficacy similar to those for Vi vaccine produced in industrial countries. CONCLUSION: The slightly higher dose of vaccine did not seem to alter efficacy significantly in China.

Adolescent↗
PubMed2001

Diffuse panbronchiolitis--a case report.

Diffuse panbronchiolitis (DPB) is a chronic progressive obstructive disease of the airways. Of unknown aetiology, it is responsive to macrolide therapy. Although not uncommon among the Japanese, it is rare in other parts of the world. We report a case of DPB in a Chinese patient in Singapore.

Anti-Bacterial Agents↗
PubMed2001

Cloning and Expression of Chinese Duck Interferon-gamma Gene.

The efficacy of cytokine therapy has been demonstrated in several viral diseases. Interferon-gamma is a cytokine that has potent antiviral property and immunomodulatory activity. To investigate the role of IFN-gamma in viral clearance during natural infection and to define the antiviral mechanism, DHBV-infected ducks was used as an animal model. To clone, express, and develop the method of quantifying DuIFN-gamma gene transcription and expression, DuIFN -gamma cDNA was amplified by RT-PCR from PHA stimulated duck PBMC. Recombinant plasmid expressing DuIFN-gamma was used to transfect COS-7, and the cell culture supernatant was analyzed by CPE inhibitory assay and MTT methods to determine the antiviral titer of IFN-gamma. The GST-DuIFN-gamma fusion protein was expressed in E.coli and purified using the GST sepharose 4B. Results indicated that the supernatant collected from COS-7 cells transfected with DuIFN-gamma cDNA was able to prevent duck fibroblasts from VSV induced CPE in a dose dependent manner. An anti-DuIFN-gamma antibody neutralized this antiviral activity.

Journal Article↗
PubMed2000

Linkage and association of tumor necrosis factor receptor 2 locus with hypertension, hypercholesterolemia and plasma shed receptor.

Tumor necrosis factor (TNF) receptor 2 (TNF-R2) has been implicated in insulin resistance and metabolic syndrome disorders, one of which is hypertension (HT). We therefore decided to test markers in and near the TNF-R2 gene (TNFRSF1B) for linkage and association with HT, as well as hypercholesterolemia, and plasma levels of the shed soluble receptor (sTNF-R2). The linkage study, which involved 200 HT Anglo-Celtic Caucasian sibpairs, indicated a sharp, significant linkage peak centered at TNFRSF1B (multipoint maximum LOD score = 2. 6 and 3.1 by weighted and unweighted MAPMAKER/SIBS, respectively; two-point LOD scores = 2.9 and 3.9 by weighted and unweighted SPLINK, respectively; P = 10(-4) by identical-by-state chi(2)). The case-control study in 134 unrelated HTs who were the offspring of two HT parents and 197 normotensives (NTs) whose parents were both NTs, indicated possible association of TNFRSF1B with HT by haplotype analysis (P = 0.008). Plasma sTNF-R2 was elevated in HTs (P < 0. 0001) and showed a correlation with systolic and diastolic blood pressure (BP) (P < 0.0002). A genotypic effect of TNFRSF1B on plasma sTNF-R2, as well as total, low and high density lipoprotein cholesterol, and diastolic BP was observed. These observations are consistent with a scheme leading to raised BP and hypercholesterolemia. In conclusion, TNFRSF1B may be a candidate gene for HT and other metabolic syndrome abnormalities.

Antigens, CD↗
PubMed2000

Cloning and characterization of a novel nuclease from shrimp hepatopancreas, and prediction of its active site.

Approximately 95% of the amino acid sequence of a shrimp (Penaeus japonicus) nuclease was derived from protease-digested peptides. A 1461-base cDNA for the nuclease was amplified and sequenced with degenerate primers based on the amino acid sequence and then specific primers by 3' and 5' RACE (rapid amplification of cDNA ends). It contains an open reading frame encoding a putative 21-residue signal peptide and a 381-residue mature protein. The N-terminus of the enzyme is pyroglutamate, deduced from composition and matrix-assisted laser desorption ionization-time-of-flight MS analyses, and confirmed by a glutamine residue in the cDNA sequence. The enzyme has 11 Cys residues, forming five intramolecular disulphides. The eleventh Cys residue was linked to a thiol compound with an estimated molecular mass of between 500 and 700 Da. A sequence similarity search revealed no homologous proteins but residues 205-255 shared a conserved active-site motif within a distinct group of nucleases. His(211) in this conserved motif was shown to be very important in catalysis by site-specific modification with (14)C-labelled iodoacetate. The shrimp nuclease, previously designated DNase I, does indeed possess a low level of hydrolytic activity towards RNA in the presence of Mg(2+) and Ca(2+). The conservation of functionally important residues during distant evolution might imply that the catalytic mechanisms are similar in these nucleases, which should be classified in one subfamily. Finally, an active-site structure for shrimp nuclease was proposed on the basis of published structural data and the results of mutational and biochemical analyses of Serratia nuclease.

Amino Acid Sequence↗
PubMed2000

Characterization of a thrombin-like enzyme from the venom of Trimeresurus jerdonii.

From the venom of Trimeresurus jerdonii, a distinct thrombin-like enzyme, called jerdonobin, was purified by DEAE A-25 ion-exchange chromatography, Sephadex G-75 gel filtration, and fast protein liquid chromatography (FPLC). SDS-PAGE analysis of this enzyme shows that it consists of a single polypeptide chain with a molecular weight of 38,000. The NH(2)-terminal amino acid sequence of jerdonobin has great homology with venom thrombin-like enzymes documented. Jerdonobin is able to hydrolyze several chromogenic substrates. The enzyme directly clots fibrinogen with an activity of 217 NIH units/mg. The fibrinopeptides released, identified by HPLC, consisted of fibrinopeptide A and a small amount of fibrinopepide B. The activities of the enzyme were inhibited by phenylmethylsulfonyl fluoride (PMSF) and p-nitrophenyl-p-guanidinobenzoate (NPGB). However, metal chelator (EDTA) had no effect on it, indicating it is venom serine protease.

Amino Acid Sequence↗
PubMed2000

The dose-response of intrathecal sufentanil added to bupivacaine for labor analgesia.

BACKGROUND: Regional analgesia for labor often is initiated with an intrathecal injection of a local anesthetic and opioid. The purpose of this prospective, randomized, blinded study was to determine the optimal dose of intrathecal sufentanil when combined with 2.5 mg bupivacaine for labor analgesia. METHODS: One hundred seventy parous parturients with cervical dilation between 3-5 cm were randomized to receive intrathecal 0 (control), 2.5, 5.0, 7.5, or 10.0 microg sufentanil combined with 2.5 mg bupivacaine, followed by a lidocaine epidural test dose, for initiation of analgesia (34 patients in each group). Visual analog scores and the presence of nausea, vomiting, and pruritus were determined every 15 min until the patient requested additional analgesia. Fetal heart rate tracings were compared between groups. RESULTS: Groups were similar for age, height, weight, oxytocin dose, duration of labor, and baseline visual analog scores. Duration of action was significantly shorter for control patients (39 +/- 25 min [mean +/- SD]) compared with those administered sufentanil, all doses (93 +/- 32, 93 +/- 47, 94 +/- 33, 97 +/- 39 min), but was not different among groups administered 2.5, 5.0, 7.5, or 10.0 microg sufentanil. More patients who received 10 microg sufentanil reported nausea and vomiting than did control patients. The severity of pruritus increased with administration of 7.5 and 10.0 microg sufentanil. There was no difference in fetal heart rate changes among groups. CONCLUSIONS: Intrathecal bupivacaine (2.5 mg) without sufentanil did not provide satisfactory analgesia for parous patients. However, bupivacaine combined with 2.5 microg sufentanil provided analgesia comparable to higher doses, with a lower incidence of nausea and vomiting and less severe pruritus.

Adult↗
PubMed2000

Detection of circulating tumor cells in venous blood of nasopharyngeal carcinoma patients by nested reverse transcriptase-polymerase chain reaction.

Nasopharyngeal carcinoma (NPC) is a radiosensitive tumor. Because of recent advances in radiation oncology, distant metastasis has become the predominant failure site after adequate radiotherapy. The purpose of this study is to establish a nested reverse transcriptase-polymerase chain reaction (RT-PCR) system and to evaluate the potential of cytokeratin 19 (CK-19) mRNA as a target for detecting micrometastasis in the blood of NPC patients. Venous blood samples from 40 patients with biopsy-proven NPC (25 previously untreated and 15 after radiotherapy) and 20 healthy volunteers were tested. We divided the 40 patients into 4 groups: cured, early stage, advanced stage, and metastasized, according to results of clinical staging work-up. Under our nested RT-PCR experimental conditions, 2 of 8 early stage patients (25.0%), 6 of 15 advanced stage patients (40%), and 6 of 8 patients with distant metastasis (75%) had CK-19 positive cells in peripheral blood (P = 0.11). No CK-19 positive cells were detected in 9 "cured" patients and 20 healthy volunteers. Our data indicated that the positive detection rate for CK-19 mRNA in peripheral blood increased as the clinical stage of disease increased, but the difference did not reach statistical significance. Longer follow-up is needed to assess the significance of CK-19 mRNA in blood, as well as its relation to subsequent metastasis and prognosis of NPC.

Adult↗
PubMed2000

Antagonistic action of caffeine against LY294002-induced apoptosis in cerebellar granule neurons.

AIM: To study the effect of caffeine on apoptosis induced by inhibition of 1-phosphatidylinositol 3-kinase in cerebellar granule neurons. METHODS: Cerebellar granule neurons culture, agar gel electrophoresis, and stress-activated protein kinase (SAPK)/c-Jun N-terminal protein kinase (JNK) assay kit to measure SAPK/JNK activity. RESULTS: LY294002 evoked apoptosis concentration-dependently in cerebellar granule neurons. But death resulting from LY294002 was prevented by caffeine in a concentration-dependent manner. The survival effect of caffeine was not affected by inhibitors of ryanodine-sensitive Ca2+ release, nor was it inhibited by L-type channel blockers and N-methyl-D-aspartate (NMDA) receptor blocker. In addition, RP-cAMP, H89, and KN62 were not able to inhibit the protective effect of caffeine. Phosphorylation of c-Jun was necessary for the induction of apoptosis induced by LY294002 in cerebellar granule neurons. But caffeine directly inhibited the activation of JNK and decreased phospho-c-Jun in granule neurons. CONCLUSION: Caffeine inhibited the activation of JNK and decreased the phosphorylation of c-Jun to protect granule neurons from LY294002-induced apoptosis.

Animals↗
PubMed2000

Parents' psychosocial problems influencing the continuity of early intervention treatment in children with developmental delay.

Developmental delay is a chronic disorder, which has a significant and continuing impact on the developmental progress of children. Whether the developmentally delayed children have continuous early intervention treatment is important for the success of early intervention. Professionals in early intervention services have been encouraged to understand parents' psychosocial problems and to further enhance their understanding of care for their delayed children. The purposes of this study were two-fold. The first was to identify the parents' psychosocial problems. The second purpose was to find parents' psychosocial variables that could be used to significantly discriminate whether the retarded children have continuously received treatment programs. A questionnaire to investigate parents' psychosocial problems was implemented. It mainly consisted of twenty descriptive items concerning parents' psychosocial conditions. Parents used a four-point Likert scale to rate the likelihood of the items. Parents also responded as to whether their child had received treatments continuously. Subjects were the parents of children who were diagnosed to have developmental delay. Factor analysis and discriminant analysis was used for statistical data examination. Analyzed data were from 207 completely finished questionnaires. Six parents' psychosocial factors were extracted via factor analysis, and they accounted for 46.9% of the variance of the twenty items. The factors were identified as family income, family members' relationships, caring skills, supporting resources, acceptance of the retarded child, and self-psychological adaptation. About half of the children had received treatment continuously. Discriminant analysis revealed that family income was crucial to parents' capacity to meet the needs for treatment.

Adult↗
PubMed2000

[Effects of simulated weightlessness on carbohydrate intake and serum lipids].

OBJECTIVE: To observe the effects of simulated weightlessness on the nutritional state and contents of serum lipids in human. METHOD: Eighteen healthy men were exposed to 21 d bed rest with -6 degrees head down tilt (HDT -6 degrees). Nutrients intake was calculated and the lipids levels were determined on the first, eleventh and twenty-first day. RESULT: Intake of the three main nutrients, carbohydrates, protein and fat met the physiological requirement essentially, but carbohydrates intake was significantly reduced in the second week. There were no significant differences among the lipid levels during different periods. CONCLUSION: Simulated weightlessness may exert a short-term and reversible influence on human nutritional intake except for lipids.

Adolescent↗
PubMed1999

Exclusion of angiotensinogen gene in molecular basis of human hypertension: sibpair linkage and association analyses in Australian anglo-caucasians.

Linkage with essential hypertension has been claimed for a microsatellite marker near the angiotensinogen gene (AGT; chromosome 1q42), as has association for the AGT variants M235T, G(-6)A and A(-20)C. To more rigorously evaluate AGT as a candidate gene for hypertension we performed sibpair analysis with multiple microsatellite markers surrounding this locus and using more sophisticated analysis programs. We also performed an association study of the AGT variants in unrelated subjects with a strong family history (two affected parents). For the linkage study, single and multiplex polymerase chain reaction (PCRs) and automated genescan analysis were conducted on DNA from 175 Australian Anglo-Celtic Caucasian hypertensives for the following markers: D1S2880-(2.1 cM)-D1S213-(2.8 cM)-D1S251-(6.5 cM)-AGT-(2.0 cM) -D1S235. Statistical evaluation of genotype data by nonparametric methods resulted in the following scores: Single-point analysis - SPLINK, P > 0.18; APM method, P > 0.25; ASPEX, MLOD < 0.28; SIB-PAIR, P > 0. 24; Multipoint analysis - MAPMAKER/SIBS, MLOD < 0.24; GENEHUNTER, P > 0.35. Exclusion scores of Lod -4.1 to -5.1 were obtained for these markers using MAPMAKER/SIBS for a lambda(s) of 1.6. The association study of G(-6)A, A(-20)C and M235T variants in 111 hypertensives with strong family history and 190 normotensives with no family history showed significant linkage disequilibrium between particular haplotypes, but we could find no association with hypertension. The present study therefore excludes AGT in the etiology of hypertension, at least in the population of Australian Anglo-Celtic Caucasians studied.

Adult↗