Biomedical subjects

W Yu

Publications and source records attributed to W Yu.

At least 19 recordsLinked to original sources

PubMed2006

A novel amplification target, DUSP26, promotes anaplastic thyroid cancer cell growth by inhibiting p38 MAPK activity.

Anaplastic thyroid cancer (ATC) is one of the most lethal of all human tumors, but cytogenetic information concerning ATC is extremely limited. Using our in-house array-based comparative genomic hybridization and 14 ATC cell lines with further fluorescence in situ hybridization analysis, we demonstrated amplification of the DUSP26 gene, known by another report as MAP kinase phosphatase-8. DUSP26 was overexpressed in ATC cell lines and primary ATC tumor samples. When overexpressed, either exogenously or endogenously, DUSP26 promoted growth of the ATC cells. DUSP26 encodes a protein containing a dual-specificity phosphatase domain that can dephosphorylate itself. DUSP26 effectively dephosphorylates p38 and has a little effect on extracellular signal-regulated kinase in ATC cells. DUSP26 protein formed a physical complex with p38, and promoted survival of ATC cells by inhibiting p38-mediated apoptosis. Our findings suggest that DUSP26 may act as an oncogene in ATC, and might be a useful diagnostic marker and therapeutic target of this disease.

Apoptosis↗

PubMed2006

Phase II study of capecitabine and irinotecan combination chemotherapy in patients with advanced gastric cancer.

The present study was conducted to evaluate the efficacy and safety of a combination regimen of capecitabine plus irinotecan in patients with advanced gastric cancer. Patients with previously untreated metastatic or recurrent, measurable gastric cancer received oral capecitabine 1000 mg m(-2) twice daily from day 1 to 14 and intravenous irinotecan 100 mg m(-2) on days 1 and 8, based on a 3-week cycle. Forty-one patients were enrolled in the current study, among whom 38 were assessable for efficacy and 40 assessable for toxicity. Three complete responses and 16 partial responses were confirmed, giving an overall response rate of 46.3%. At a median follow-up of 269 days, the median time to progression and overall survival were 5.1 and 8.6 months, respectively. Grade 3/4 neutropenia occurred in four patients and grade 3 febrile neutropenia was observed in two patients. Grade 3 diarrhoea and grade 2 hand-foot syndrome occurred in six patients and eight patients, respectively. The combination of capecitabine and irinotecan was found to be well tolerated and effective in patients with advanced gastric cancer. Accordingly, this regimen can be regarded as one of first-line treatment options for advanced gastric cancer.

Adenocarcinoma↗

PubMed2006

A review of adjuvant therapy for resected primary gastric cancer with an update on Taegu's phase III trial with intraperitoneal chemotherapy.

AIMS: Because patients with advanced gastric cancers have less than 50% chance of cure after R0 resection, the need for an adjuvant treatment to eradicate residual microscopic disease is clear. The major treatment strategy during the last decades has been postoperative systemic therapy. The results of published trials were reviewed. And, perioperative intraperitoneal chemotherapy as an adjuvant to potentially curative surgery was evaluated. METHODS: A literature search on this topic was performed for articles relating to clinical trials using adjuvant chemotherapy in the management of gastric cancer. Subset analyses of Taegu's phase III trial of early postoperative intraperitoneal chemotherapy were performed. RESULTS: Even after extended lymphadenectomy, the peritoneal surface and resection site had a high incidence of recurrence. Postoperative systemic chemotherapy treatment regimens available in the past showed no major improvement in survival. One of new approaches currently undergoing study was intraperitoneal chemotherapy given in the perioperative period. The Taegu data showed this treatment reduced the incidence of peritoneal recurrence and thereby improved the survival rate after potentially curative surgery for gastric cancer. CONCLUSIONS: The eradication of micrometastatic foci in the peritoneal cavity can be achieved by the perioperative intraperitoneal administration of chemotherapeutic agents. Patients with serosa-positive gastric cancer are most likely to benefit from adjuvant intraperitoneal chemotherapy.

Antineoplastic Agents↗

PubMed2006

Randomized clinical trial of splenectomy versus splenic preservation in patients with proximal gastric cancer.

BACKGROUND: Preservation or removal of the spleen during total gastrectomy for proximal gastric cancer is a matter of debate. METHODS: A randomized clinical trial included patients with gastric adenocarcinoma who underwent total gastrectomy either with (104 patients) or without (103) splenectomy. Postoperative outcome in the two groups was compared, including morbidity, mortality and survival. RESULTS: Gastrectomy combined with splenectomy tended to be associated with slightly higher morbidity and mortality rates, a slightly greater incidence of lymph node metastasis at the splenic hilum and along the splenic artery, and marginally better survival, but there were no statistically significant differences between the groups. Splenectomy had no impact on survival in patients with metastatic lymph nodes at the hilum of the spleen or in those with metastatic lymph nodes along the splenic artery. CONCLUSION: These results do not support the use of prophylactic splenectomy to remove macroscopically negative lymph nodes near the spleen in patients undergoing total gastrectomy for proximal gastric cancer.

Adenocarcinoma↗

PubMed2006

Rapid, field-adapted indirect enzyme-linked immunosorbent assay for detection of antibodies in bovine whole blood and serum to Brucella abortus.

A simple, rapid, field-adapted indirect enzyme-linked immunoassay (FldELISA) for the detection of antibodies to Brucella abortus in whole blood and serum has been developed. This assay detects antibodies to B. abortus in approximately 15 min or less. Over a 3-month period, this assay has consistently identified immunized and nonimmunized animals, while the percent coefficient of variation for each immunized animal has been less than 20%. As with any indirect enzyme-linked immunoassay, quality control can be established and maintained. Using defined positive and negative sera, the sensitivity and specificity of the FldELISA was 100% and 94.2%, respectively. As a model, this test can be readily extended to other disease applications that use lipopolysaccharide or other stable antigens for the detection of antibodies, such as those to Salmonella spp., Escherichia coli, or Yersinia spp.

Animals↗

PubMed2006

Estimating the number of people at risk for and living with HIV in China in 2005: methods and results.

BACKGROUND: No new estimates of HIV infection have been available for China since 2003. However, since then, data availability has increased dramatically. OBJECTIVES: To use internationally recommended methods to make new estimates of the number of people exposed to HIV in China, the number living with HIV, and the number of new HIV infections and deaths in 2005. METHODS: The UNAIDS Workbook method was adapted to meet the needs of China. Local data were used to estimate the size of each risk population and HIV prevalence by risk group for every prefecture. These estimates were combined into provincial and national estimates. The UNAIDS Estimates and Projections Package and Spectrum were used to derive estimates of incidence and mortality from prevalence data, taking into account treatment. RESULTS: It was estimated that 650,000 people are living with HIV/AIDS in China (range 540,000-760,000), of whom 70,000 were newly infected in 2005 (range 60,000-80,000). Between 20,000 and 30,000 people are estimated to have died of HIV in 2005. The new estimate compares with an estimate of 840,000 people living with HIV/AIDS in 2003 (range 650,000-1,020,000). The estimated number of infected former plasma donors fell from 199,000 to 55,000. Infections remain concentrated among drug injectors, those buying and selling sex, and men who have sex with men. CONCLUSION: The new estimates are based on a much wider range of surveillance data as well as mass screening of former plasma donors, and are made at the prefecture level. More limited data from high prevalence provincial surveillance sites led to past estimates that now seem too high. New infections outpace death, and the HIV epidemic in China is still growing.

China↗

PubMed2006

Antitumor activities of the four sesquiterpene lactones from Elephantopus scaber L.

AIM: To evaluate antitumor activity of sesquiterpene lactones (scabertopin (ES-2), isoscabertopin (ES-3), deoxyelephantopin (ES-4), isodeoxyelephantopin (ES-5)) isolated from Elephantopus scaber L. in vitro and in vivo. METHODS: SMMC-7721, Caco-2 and HeLa cell lines were treated with ES-2,3,4,5. Cell viability was determined by MTT assay. Agarose gel electrophoresis was used to detect DNA fragmentation. To evaluate in vivo antitumor activity of ES-4, experimental murine tumor model was used. RESULTS: It was shown that ES-2, ES-4, ES-5 exhibited significant antitumor effect in vitro in a concentration-dependent manner. However, the effect of ES-3 on the growth of tested cell lines was relatively weak. In HeLa cells exposed to ES-4 for 48 h, morphological changes and DNA ladder pattern evidencing on apoptosis were detected. ES-4 revealed in vivo antitumor activity. CONCLUSION: Antitumor activity of studied sesquiterpene lactones may be due, at least in part, to induction of apoptosis in vitro. ES-4 possesses also antitumor activity in vivo.

Antineoplastic Agents, Phytogenic↗

PubMed2005

Serological discrimination by indirect enzyme immunoassay between the antibody response to Brucella sp. and Yersinia enterocolitica O:9 in cattle and pigs.

A rapid, inexpensive and rugged serological test that distinguishes cattle and swine infected with Brucella sp. or Yersinia enterocolitica O:9 is described. The test protocol, which is an indirect enzyme immunoassay uses a high concentration of divalent cation chelating agents to minimize binding of Y. enterocolitica O:9 antibody to rough lipopolysaccharide antigen derived from B. abortus RB51. No false positive reactions were observed when testing 100 Canadian cattle and swine without any evidence of brucellosis. The assay detected 91.6% of cattle (n=155) and 93.5% (n=31) of swine infected with Brucella sp. Sera from 58 cattle and 38 swine exposed to Y. enterocolitica O:9 were negative while only 20 sera from 121 'false positive' reactors of unspecified origin gave low level positive reactions, eliminating 84% of the false positive reactions.

Animals↗

PubMed2005

Coexistence of superconductivity and antiferromagnetism probed by simultaneous nuclear magnetic resonance and electrical transport in (TMTSF)2PF6 system.

We report simultaneous NMR and electrical transport experiments in the pressure range near the boundary of the antiferromagnetic spin density wave (SDW) insulator and the metallic/superconducting (SC) phase in (TMTSF)2PF6. Measurements indicate a tricritical point separating a line of second-order SDW/metal transitions from a line of first-order SDW/metal(SC) transitions with coexistence of macroscopic regions of SDW and metal(SC) order, with little mutual interaction but strong hysteretic effects. NMR results quantify the fraction of each phase.

Journal Article↗

PubMed2005

Long-term outcome of endovascular stenting for symptomatic basilar artery stenosis.

Eighteen patients underwent stenting for symptomatic basilar artery stenosis. There were three major periprocedural complications (16.7%) without fatality. At a mean 26.7 +/- 12.1-month follow-up, 15 patients (83.3%) had an excellent long-term outcome. Only one patient (5.6%) had moderate disability from recurrent stroke, and two patients died of medical illness at 30 and 36 months after stenting. In this uncontrolled study, stenting appeared to be effective in reducing stroke risk and death and worthy of further scrupulous trial.

Aged↗

PubMed2005

77Se NMR probe of magnetic excitations of the magic angle effect in (TMTSF)2PF6.

We report 77Se spin-lattice relaxation rates for (TMTSF)2PF6, carried out in the regime where a set of spectacular transport anomalies known as the "magic angle effects" are observed. In situ resistance measurements (R(zz)) were used to verify the experimental conditions and give precise sample alignment information. We found that the 77Se T-11 exhibits no significant changes as the magnetic-field orientation is rotated through the magic angles, and conclude that there is no evidence for either a single-particle gap or a spin gap. The clearly observed field-induced spin-density wave transition temperature is also, unexpectedly, not enhanced at the magic angles.

Journal Article↗

PubMed2005

An effective thermal conductivity model of nanofluids with a cubical arrangement of spherical particles.

The theoretical investigation of the effective thermal conductivities of nanofluids, a new class of solid-liquid suspensions, is important in both predicting and designing nanofluids with effective thermal conductivities. We have developed a new thermal conductivity model for nanofluids that is based on the assumption that monosized spherical particles are uniformly dispersed in the liquid and are located at the vertexes of a simple cubic lattice, with each particle surrounded by a liquid layer having a thermal conductivity that differs from that of the bulk liquid. This model nanofluid with a cubical arrangement of nanoparticles gives a more practical upper limit of thermal conduction than a model nanofluid with a parallel arrangement of nanoparticles. The new model unexpectedly shows a nonlinear relationship of thermal conductivity with particle concentration, whereas the conductivity-concentration curve changes from convex upward to concave upward with increasing volume concentration. The effects of particle and layer parameters on the effective thermal conductivities are also analyzed. A comparison of predicted thermal conductivity values and experimental data shows that the predicted values are much higher than the experimental data, a finding that indicates that there is a potential to further improve the effective thermal conductivities of nanofluids with more uniformly dispersed particles.

Hot Temperature↗

PubMed2005

Towards single screening tests for brucellosis.

This paper describes an indirect enzyme-linked immunosorbent assay (I-ELISA) and a fluorescence polarisation assay (FPA), each capable of detecting antibody in several species of hosts to smooth and rough members of the genus Brucella. The I-ELISA uses a mixture of smooth lipopolysaccharide (SLPS) and rough lipopolysaccharide (RLPS) as the antigen, and a recombinant protein A/G conjugated with horseradish peroxidase as the detection reagent. When using individually determined cutoff values, the SLPS/RLPS combined-antigen I-ELISA detected antibody in slightly more animals exposed to SLPS or to RLPS than did I-ELISA procedures using each individual antigen separately. Similarly, the assay using combined antigens detected antibody in slightly fewer animals not exposed to Brucella sp. When a universal cutoff of 10% positivity was used (relative to strongly positive control sera of each species), the overall performance index (percentage sensitivity plus percentage specificity) value decreased by 1.0 (from 199.4 to 198.4). In the FPA, it was not possible to use a universal cutoff without significant loss of performance. The overall sensitivity value for the FPA using the combined FPA antigen was 1.0% lower than using the O-polysaccharide (OPS) from SLPS and 9.1% higher than using the core antigen (CORE) from RLPS. When the combined antigen was used, the FPA specificity was slightly higher (1.2%) than from only the OPS, and considerably higher (12.6%) than the CORE. Overall, both the I-ELISA and the FPA with combined antigens were suitable as screening tests for all species of Brucella in the animal species tested.

Animal Diseases↗

PubMed2004

Enzyme immunoassay for the diagnosis of brucellosis: chimeric Protein A-Protein G as a common enzyme labeled detection reagent for sera for different animal species.

A recombinant protein combining the immunoglobulin binding sites of Proteins A and G, conjugated with horseradish peroxidase was used as a universal detection reagent for the assessment of antibodies against Brucella spp. The reagent was applied in an indirect enzyme immunoassay for detection of antibodies to smooth lipopolysaccharide antigen in sera from Brucella spp. exposed and non-exposed cattle, sheep, goats and pigs and to antibodies to rough lipopolysaccharide in sheep, dogs and cattle. The results were similar to those obtained when murine monoclonal antibody-enzyme conjugates were used. An added advantage was that a universal cut-off for all tests using the proteins A and G detection reagent could be established, simplifying diagnostic interpretation of the data.

Animals↗

PubMed2004

Phase inhomogeneity of the itinerant ferromagnet MnSi at high pressures.

The pressure induced quantum phase transition of the weakly ferromagnetic metal MnSi is studied using zero-field 29Si NMR spectroscopy and relaxation. Below P(*) approximately 1.2 GPa, the intensity of the signal and the nuclear spin-lattice relaxation are independent of pressure, even though the amplitude of the magnetization drops by 20% from the ambient-pressure amplitude. For P>P(*), the decreasing intensity within the experimentally detectable bandwidth signals the onset of an inhomogeneous phase that persists to the highest pressure measured, P>/=1.75 GPa, which is well beyond the known critical pressure P(c)=1.46 GPa. Implications for the non-Fermi liquid behavior observed for P>P(c) are discussed.

Journal Article↗

PubMed2004

Inhomogeneous electronic structure probed by spin-echo experiments in the electron doped high-Tc superconductor Pr1.85Ce0.15CuO4-y.

63Cu nuclear magnetic resonance spin-echo decay rate (T-12) measurements are reported for the normal and superconducting states of a single crystal of Pr(1.85)Ce(0.15)CuO(4-y) in a magnetic field B(0)=9 T over the temperature range 2<T<200 K. The spin-echo decay rate is temperature dependent for T<55 K and has a substantial dependence on the radio frequency (rf) pulse parameters below T approximately 25 K. This dependence indicates that T-12 is strongly effected by a local magnetic field distribution that can be modified by the rf pulses, including ones that are not at the nuclear Larmor frequency. The low-temperature results are consistent with the formation of a static inhomogeneous electronic structure that couples to the rf fields of the pulses.

Journal Article↗

PubMed2004

Using GIS in government: an overview of the VHA's Healthcare Atlas, FY-2000.

The amount of VA data available for analysis can be overwhelming to individuals who need to translate these data into usable information. The Atlas, using current GIS technology, was funded to provide data in a comprehensive guide. Patients were identified using a disease classification scheme based on Kaiser Permanente methodology and the Clinical Classifications Software (AHRQ). Utilization data were extracted from the Medical SAS Datasets. Cost data were obtained from the HERC. GIS tools were used to create the Atlas. The Atlas overviews the location of VA hospitals; profiles veteran, VA enrollee and patient populations; examines overall utilization; depicts patterns in healthcare use by specific disease cohorts; and examines geographic variations in costs. This product will enhance knowledge of VA's enrolled patient population and their healthcare needs, and provide background information that will improve the formulation of specific research questions to address those needs.

Databases, Factual↗

PubMed2004

A sterically stabilized immunolipoplex for systemic administration of a therapeutic gene.

A sterically stabilized immunolipoplex (TsPLP), containing an antitransferrin receptor single-chain antibody fragment (TfRscFv)-PEG molecule, has been developed to specifically and efficiently deliver a therapeutic gene to tumor cells. A postcoating preparation strategy was employed in which a DNA/lipid complex (lipoplex) was formed first and then sequentially conjugated with PEG and TfRscFv. The complex prepared by this method was shown to be superior in ability to deliver genes to tumor cells than when prepared by a common precoating strategy, in which DNA is mixed with TfRscFv-PEG conjugated liposome. Using prostate cancer cell line DU145, a comparison was made between the in vitro and in vivo gene delivery efficiencies of four complexes, Lipoplex (LP), PEG-Lipoplex (PLP), TfRscFv-PEG-Lipoplex (TsPLP) and our standard TfRscFv-Lipoplex (TsLP). In vitro, the order of transfection efficiency was TsLP>LP approximately TsPLP>PLP. However, in vivo the order of transfection efficiency, after systemic administration via the tail vein, was TsPLP>TsLP>LP or PLP with TsPLP-mediated exogenous gene expression in tumor being two-fold higher than when mediated by TsLP. This suggests that the in vitro transfection efficiency of TsPLP was not indicative of its in vivo efficiency. In addition, it was found that the level of exogenous gene expression in the tumor mediated by TsPLP was higher than that mediated by TsLP and did not decrease over the time. More importantly, high exogenous gene expression in tumor, but low expression in liver, was observed after an i.v. delivery of TsPLP carrying either the GFP reporter gene or the p53 gene, indicating that tumor preferential targeting was maintained by this complex in the presence of PEG. These findings show that incorporation of PEG into our targeted lipoplex results in a more efficient delivery of the complex to the tumor cells, possibly by inhibiting the first pass clearance observed with non-PEG containing liposomes. Therefore, these data demonstrate that TsPLP is a improvement over our previously established tumor targeted gene delivery complex for systemic gene therapy of cancer.

Animals↗