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Biomedical subjects

Qin Wang

Publications and source records attributed to Qin Wang.

At least 109 records · Page 6Linked to original sources
PubMed2004

[Food nourishment utilization efficiency of different month aged sheep].

Studies on the food nourishment utilization efficiency of different month aged sheep showed that under same food nourishment condition, the ingested nourishment, weight increase, and nourishment depletion per unit weight increase of sheep were increased with the ingestion of dry matter, and the protein content of 34 months old sheep was significantly higher than that of 22 months old sheep (P < 0.01), and the latter was significantly higher than that of 10 months old sheep (P < 0.01). There was a significant difference of utilization efficiency of the ingested nourishment between 34 months old and 22 months old sheep (P < 0.05) and between 10 months old and 22 months old sheep (P < 0.01). The weight increase was not significantly different (P > 0.05) between 34 months old and 22 months old sheep and between 10 months old and 22 months old sheep, but it was significantly different between 34 months old and 10 months old sheep (P < 0.05). The feed conversion rate among them was not different. All the results showed that 10-22 months old sheep had high production efficiency, and could produce high quality mutton, and hence, this section of age was the suitable age of sheep to be butchered.

Age Factors↗
PubMed2004

Antitumor reactivity of splenocytes primed in vivo with dendritic-cell-based vaccine and secondarily activated with a cocktail of cytokines in vitro.

AIM: To evaluate the antitumor reactivity of splenocytes primed in vivo with dendritic cell (DC) based vaccine and secondarily activated with cocktail of cytokines in vitro. METHODS: Tumor lysate pulsed DC were used to generate effector T cells in the murine L615 leukemia model. DC were induced and pulsed with tumor lysate. The splenocytes from the DC based vaccine primed mice were termed VPS. Some VPS were activated with anti-CD3 alone (VPS-CD3), the other cells were activated with a cocktail of cytokines including IFN-gamma, IL-1beta, anti-CD3 and IL-2 (VPSC). RESULTS: Both VPS and VPS-CD3 showed moderate IFN-gamma release to stimulatory tomor cells in vitro and antitumor capacity in vivo. However, VPSC showed much higher IFN-gamma release and far superior antitumor capacity than the other cells in this leukemia model. CONCLUSION: The result here indicates that tumor lysate pulsed DC can be used as a strategy to generate effector T cells which can be further activated with a cocktail of cytokines for adoptive immunotherapy.

Animals↗
PubMed2004

[Effects of site condition on litterfall and related nutrient return in Pinus luchuensis plantations].

Over three years study on the dynamics of litterfall and related nutrient return in Pinus luchuensis plantations at different sites of northern Okinawa Island, Japan showed that the annual litterfall biomass ranged from 6.54 to 8.05 Mg x hm(-2) x yr(-1), with a peak from June to July. Typhoons had a strong influence on the timing and mass of litterfall. There were significant differences in nutrient concentrations among the different components of litterfall. The annual total nutrient input from litterfall ranged from 113.4 to 154.6 kg x hm(-2) x yr(-1), of which, N input was the greatest and contributed 42.2% of the total. The nutrient input was in order of N > Ca > K > Mg > Na > P. Due to the significantly different site conditions, there were significant differences in annual litterfall mass and related nutrient inputs between the two sampling stands. The annual mean litterfall mass of the sampling stand P1 on the lower slope reached 8.05 Mg x hm(-2) x yr(-1), which was 23.1% greater than that of P2 on the upper slope. The annual mean nutrient inputs were N 66.04, P 1.63, K 17.42, Ca 48.31, Mg 14.65 and Na 6.57 kg x hm(-2) x yr(-1), and were 39.7%, 48.8%, 39.4%, 32.9%, 24.8% and 49.3% higher in P1 than in P2, respectively. The nutrient use efficiency in litter production was higher in P2 (e.g., N 138, P 5945 and K 523) than in P1 (e.g., N 122, P 4934 and K 462), which should be attributed to the relatively lower fertility of soil in P2. The results from the study suggested that Pinus luchuensis plantation in Okinawa was a high efficiency system.

Biomass↗
PubMed2003

Protein-lipid interactions in zein films investigated by surface plasmon resonance.

Experiments on the adsorption of alpha-zein (characterized by SDS-PAGE) from aqueous ethanol and 2-propanol solutions onto hydrophilic and hydrophobic surfaces are reported. Zein adsorption onto self-assembled monolayers (SAMs) was detected by surface plasmon resonance (SPR). Gold substrates were prepared by thermal evaporation on glass slides. Gold-coated surfaces were modified by depositing SAMs of either a long-chain carboxylic acid terminated thiol [COOH(CH2)(10)SH] or a methyl-terminated alkanethiol [CH3(CH2)(7)SH]. Experimental measurements indicated that zein interacted with both hydrophilic and hydrophobic surfaces. Zein concentration affected the thickness of bound zein layers. The estimated thickness of the zein monolayer deposited on hydrophilic surfaces was 4.7 nm. Zein monolayer thickness on hydrophobic surfaces was estimated at 4.6 nm. The topography of zein layers was examined by atomic force microscopy (AFM) after solvent was evaporated. Surface features of zein deposits depended on the adsorbing surface. On hydrophilic surfaces, roughness values were high and distinct ring-shaped structures were observed. On hydrophobic surfaces, zein formed a uniform and featureless coverage.

2-Propanol↗
PubMed2003

Activation of SRC tyrosine kinases in response to ICAM-1 ligation in pulmonary microvascular endothelial cells.

Previous studies demonstrated that ICAM-1 ligation on human pulmonary microvascular endothelial cells (ECs) sequentially induces activation of xanthine oxidase and p38 MAPK. Inhibition of these signaling events reduces neutrophil migration to the EC borders. This study examined the role of SRC tyrosine kinases in ICAM-1-initiated signaling within these ECs. Cross-linking ICAM-1 on tumor necrosis factor-alpha-pretreated ECs induced an increase in the activity of SRC tyrosine kinases. This increase was inhibited by allopurinol (a xanthine oxidase inhibitor), Me2SO (a hydroxyl radical scavenger), or deferoxamine (an iron chelator). Phenylarsine oxide, a tyrosine phosphatase inhibitor, reduced the base-line activity of SRC as well as the increase in SRC activity induced by ICAM-1 cross-linking. Specific inhibition of the protein expression of the SRC homology 2-containing protein-tyrosine phosphatase-2 (SHP-2) by an antisense oligonucleotide prevented the induced SRC activation but had no effect on the basal SRC activity. Activation of SRC tyrosine kinases was accompanied by tyrosine phosphorylation of ezrin at Tyr-146, which was inhibited by PP2, an SRC tyrosine kinase inhibitor. Moreover, PP2 completely inhibited p38 activation, suggesting a role for SRC tyrosine kinases in p38 activation. These data demonstrate that ICAM-1 ligation activates SRC tyrosine kinases and that this activation requires SHP-2 as well as production of reactive oxygen species generated from xanthine oxidase. Activation of SRC tyrosine kinases in turn leads to tyrosine phosphorylation of ezrin, as well as activation of p38, a kinase previously identified to be required for cytoskeletal changes induced by ICAM-1 ligation and for neutrophil migration along the EC surface.

Allopurinol↗
PubMed2003

IL-1 induced release of Ca2+ from internal stores is dependent on cell-matrix interactions and regulates ERK activation.

The cellular mechanisms that modulate interleukin-1 (IL-1) signaling are not defined. In fibroblasts, IL-1 signaling is affected by the nature of cell-matrix adhesions including focal adhesions, adhesive domains that sequester IL-1 receptors. We conducted studies to elucidate which steps of cellular Ca2+ handling are affected by focal adhesions and by which mechanisms focal adhesions modulate IL-1-induced Ca2+ signals and ERK activation in human gingival fibroblasts. Cells were plated on poly-l-lysine or fibronectin and treated with tenascin, Hep-I, or SPARC peptides to inhibit focal adhesion formation. These treatments blocked IL-1 and thapsigargin-induced Ca2+ release from the endoplasmic reticulum, indicating that the ER-release pathway is focal adhesion dependent. Focal adhesions were also required for Ca2+ entry through store-operated channels and for IL-1-induced ERK activation. Thus interactions with the extracellular matrix and focal adhesion formation regulate IL-1-induced generation of intracellular Ca2+ signals that in turn are required for ERK activation.

Calcium↗
PubMed2003

[Systematic review of benefits and harms of artemisinin-type compounds for preventing schistosomiasis].

OBJECTIVE: To assess the benefits and harms of artemisinin-type compounds for preventing schistosomiasis. METHOD: The quality of included randomised controlled trials with the people at risk of contacting schistosomiasis were evaluated and Meta-analysis was conducted. RESULTS: We found ten randomised controlled trials relating to our question. Of them, four trials were multi-centre studies, others were single centre studies. Numbers of participants in the trials ranged from 318 to 5,098, total 12,829. The total OR of 0.11 (95% CI 0.06 to 0.21) indicated that those who were administrated artemisinin-type compounds were significantly less infected with Schistosoma japonica than those who were administrated placebo. CONCLUSION: Artemisinin-type compounds are effective drug for preventing Schistosomiasis japonica infection. Fifteen days interval schemes of artesunate and artemether be considered preferable to seven days interval scheme and were associated with very few side effects. More high quality controlled trials are required for assessing which scheme is the better. These studies should be large.

Adult↗
PubMed2003

STR polymorphisms of "forensic loci" in the northern Han Chinese population.

A preliminary Chinese DNA database has been constructed by the analysis of samples from 2,211 Han Chinese in Liaoyang City, northeast China. Thirteen autosomal tetranucleotide short tandem repeats (STRs) widely used in forensic identification were selected for the DNA profiling, together with the X-Y homologous gene Amelogenin for sex determination. Only one of the 13 autosomal loci showed significant deviation from Hardy-Weinberg equilibrium in the individuals genotyped. The cumulative discrimination power and power of exclusion of the 13 loci were greater than 0.999999999 and 0.9999888, respectively, giving an average match probability of 5.5 x 10(-15) for the population. Allelic distributions at the vWA, TH01, D13S317, and D16S539 loci differed from African-Americans and US Caucasians, and more detailed population data at these four loci may be needed to ensure their applicability for forensic purposes in Chinese populations. Previously unreported alleles were detected at several loci (some at relatively high frequencies), suggesting the need for their inclusion in the reference allelic ladder to meet the practical standard of forensic profiling in certain Chinese ethnic sub-populations. The preliminary DNA database provides base-line information applicable to the construction of a National Index System for criminal DNA profiling in PR China.

Alleles↗
PubMed2003

The NOG1 GTP-binding protein is required for biogenesis of the 60 S ribosomal subunit.

NOG1 is a nucleolar GTP-binding protein present in eukaryotes ranging from trypanosomes to humans. In this report we demonstrate that NOG1 is functionally linked to ribosome biogenesis. In sucrose density gradients Trypanosoma brucei NOG1 co-sediments with 60 S ribosomal subunits but not with monosomes. 60 S precursor RNAs are co-precipitated with NOG1. Together with the nucleolar localization of NOG1, these data indicate that NOG1 is associated with a precursor particle to the 60 S subunit. Disruption of NOG1 function through RNA interference led to a dramatic decrease in the levels of free 60 S particles and the appearance of an atypical rRNA intermediate in which ITS2 was not cleaved. Overexpression of mutant nog1 with a defect in its GTP binding motif on a wild type background caused a modest defect in 60 S biogenesis and a relative decrease in processing of the large subunit rRNAs. In contrast to the mutant protein, neither the N-terminal half of NOG1, which contains the GTP binding motifs, nor the C-terminal half of NOG1 associated with pre-ribosomal particles, although both localized to the nucleolus.

Animals↗
PubMed2003

Nickel-induced histone hypoacetylation: the role of reactive oxygen species.

The carcinogenicity of specific insoluble nickel compounds is mainly due to their intracellular generation of Ni2+ ion and its suppression on gene transcription, while the inhibition of Ni2+ on histone acetylation plays an important role in the suppression or silencing of genes. Recent studies on Ni2+ and histone H4 acetylation suggest that Ni2+ inhibits the acetylation of histone H4 through binding with its N-terminal histidine-18. It is well known that bound Ni2+ readily produces reactive oxygen species (ROS) in vivo, a critical factor inversely related with the occurrence of resistance of mammalian cells to Ni2+. Thus, we tried to find the possible role of ROS in the induction of Ni2+ on histone acetylation in the present study. We found that a high concentration of Ni2+ (no less than 600 microM) caused a significant decrease of histone acetylation in human hepatoma cells. This inhibition was shown to result mainly from the influence of Ni2+ on the overall histone acetyltransferase (HAT) activity indicated by the histone acetylation assay with the presence of a specific histone deacetylase (HDAC) inhibitor, trichostatin A (TSA). The in vitro HAT and HDAC assays further confirmed this result. At the same time, we found that the exposure of hepatoma cells to Ni2+ generated ROS. Coadministration of hydrogen peroxide with Ni2+ generated more ROS and more histone acetylation inhibition. Addition of the antioxidants 2-mercaptoethanol (2-ME) at 2 mM or N-acetyl-cysteine (NAC) at 1 mM, with Ni2+ together, completely suppressed ROS generation and significantly diminished the induced histone hypoacetylation. The data presented here prove that the ROS generation plays a role in the inhibition of histone acetylation, and, hence, the gene suppression and carcinogenesis caused by Ni2+ exposure, providing a new door for us to continuously understand the mechanism of ROS in the carcinogenicity of Ni2+ and the resistance of mammalian cells to Ni2+.

Acetylation↗
PubMed2003

Spinophilin stabilizes cell surface expression of alpha 2B-adrenergic receptors.

The third intracellular (3i) loops of the alpha 2A- and alpha 2B-adrenergic receptor (AR) subtypes are critical for retention of these receptors at the basolateral surface of polarized Madin-Darby canine kidney (MDCKII) cells at steady state. The third intracellular loops of the alpha 2A, alpha 2B, and alpha 2C-AR subtypes interact with spinophilin, a multidomain protein that, like the three alpha 2-AR subtypes, is enriched at the basolateral surface of MDCKII cells. The present studies provide evidence that alpha 2-AR interaction with spinophilin contributes to cell surface stabilization of the receptor. We exploited the unique targeting profile of the alpha 2B-AR subtype in MDCKII cells: random delivery to apical and basolateral surfaces with rapid (t(1/2) < or = 60 min) apical versus slower (t(1/2) = 10-12 h) basolateral turnover. Apical delivery of a spinophilin subdomain containing the alpha 2-AR-interacting region (Sp151-483) by fusion with apically targeted p75NTR extended the half-life of alpha 2B-AR at the apical surface to approximately 3.6 h and eliminated the rapid phase (0-60 min) of alpha 2B-AR turnover on that surface. Furthermore, we examined alpha 2B-AR turnover at the surface of mouse embryo fibroblasts derived from wild type (Sp+/+) or spinophilin knock-out (Sp-/-) mice. Two independent experimental approaches demonstrated that agonist-evoked internalization of HA-alpha 2B-AR was accelerated in mouse embryo fibroblasts derived from Sp-/- mice. These findings are consistent with the interpretation that endogenous spinophilin contributes to the stabilization of alpha 2B-AR and presumably all three alpha2-AR subtypes at the surface of target cells and may act as a scaffold that could link alpha 2-ARs to proteins interacting with spinophilin via other domains.

Adrenergic alpha-Agonists↗
PubMed2003

The protein tyrosine phosphatase SHP-2 regulates interleukin-1-induced ERK activation in fibroblasts.

Focal adhesion complexes are actin-rich, cytoskeletal structures that mediate cell adhesion to the substratum and also selectively regulate signal transduction pathways required for interleukin (IL)-1beta signaling to the MAP kinase, ERK. IL-1-induced ERK activation is markedly diminished in fibroblasts deprived of focal adhesions whereas activation of p38 and JNK is unaffected. While IL-1 signaling is known to involve the activity of protein and lipid kinases including MAP kinases, FAK, and PI3K, little is known about the role of phosphatases in the regulation of IL-1 signal generation and attenuation. Here we demonstrate that SHP-2, a protein tyrosine phosphatase present in focal adhesions, modulates IL-1-induced ERK activation and the transient actin stress fiber disorganization that occurs following IL-1 treatment in human gingival fibroblasts. Using a combination of immunoblotting, immunoprecipitation, and immunostaining we show that SHP-2 is present in nascent focal adhesions and undergoes phosphorylation on tyrosine 542 in response to IL-1 stimulation. Blocking anti-SHP-2 antibodies, electoporated into the cytosol of fibroblasts, inhibited IL-1-induced ERK activation, actin filament assembly, and cell contraction, indicating a role for SHP-2 in these processes. In summary, our data indicate that SHP-2, a focal adhesion-associated protein, participates in IL-1-induced ERK activation likely via an adaptor function.

3T3 Cells↗
PubMed2003

Activity of human monocytes in IgE antibody-dependent surveillance and killing of ovarian tumor cells.

We have previously shown that a chimeric IgE antibody against the folic acid receptor (MOv18 IgE) inhibits tumor growth in a SCID mouse model of ovarian carcinoma. MOv18 IgE gave greater protection than the corresponding chimeric MOv18 IgG1. We have now confirmed these effects in a nude-mouse model of ovarian carcinoma and have demonstrated for the first time that human monocytes are active in IgE antibody-dependent cell-mediated cytotoxicity. Injection of tumor-bearing mice with PBMC and MOv18 IgE led to infiltration of monocytes into the tumors and prolonged survival of the mice. Incubation of PBMC or purified monocytes and MOv18 IgE with ovarian tumor cells in vitro resulted in tumor cell killing proportional to the expression of unoccupied FcepsilonRI on monocytes.We observed phagocytosis of tumor cells by the monocytes in vitro. Our results suggest that tumor-specific IgE antibodies may be exploited for immunotherapy of cancer.

Animals↗
PubMed2003

An exploratory instrumental variable analysis of the outcomes of localized breast cancer treatments in a medicare population.

This study is motivated by the potential problem of using observational data to draw inferences about treatment outcomes when experimental data are not available. We compare two statistical approaches, ordinary least-squares (OLS) and instrumental variables (IV) regression analysis, to estimate the outcomes (three-year post-treatment survival) of three treatments for early stage breast cancer in elderly women: mastectomy (MST), breast conserving surgery with radiation therapy (BCSRT), and breast conserving surgery only (BCSO). The primary data source was Medicare claims for a national random sample of 2907 women (age 67 or older) with localized breast cancer who were treated between 1992 and 1994. Contrary to randomized clinical trial (RCT) results, analysis with the observational data found highly significant differences in survival among the three treatment alternatives: 79.2% survival for BCSO, 85.3% for MST, and 93.0% for BCSRT. Using OLS to control for the effects of observable characteristics narrowed the estimated survival rate differences, which remained statistically significant. In contrast, the IV analysis estimated survival rate differences that were not significantly different from 0. However, the IV-point estimates of the treatment effects were quantitatively larger than the OLS estimates, unstable, and not significantly different from the OLS results. In addition, both sets of estimates were in the same quantitative range as the RCT results.We conclude that unadjusted observational data on health outcomes of alternative treatments for localized breast cancer should not be used for cost-effectiveness studies. Our comparisons suggest that whether one places greater confidence in the OLS or the IV results depends on at least three factors: (1) the extent of observable health information that can be used as controls in OLS estimation, (2) the outcomes of statistical tests of the validity of the instrumental variable method, and (3) the similarity of the OLS and IV estimates. In this particular analysis, the OLS estimates appear to be preferable because of the instability of the IV estimates.

Aged↗
PubMed2003

Albumin at the start of peritoneal dialysis predicts the development of peritonitis.

BACKGROUND: Both peritonitis and serum albumin level are associated with morbidity and mortality in peritoneal dialysis (PD) patients. Severe cases of peritonitis result in hypoalbuminemia. However, it is not clear whether hypoalbuminemia predicts the development of peritonitis. METHODS: We performed a retrospective analysis of a prospectively collected database from six centers in western Pennsylvania and West Virginia. Incident PD patients with a Charlson Comorbidity Index (CCI) score at the start of PD therapy and serum albumin level measured within 30 days of initiation were selected. Poisson regression was used to analyze predictors of peritonitis. RESULTS: Three hundred ninety-three patients had a CCI score and serum albumin level measured at the start of PD therapy. Overall peritonitis rate was 0.65 episodes/dialysis-year. Significant univariate predictors were albumin level (rate ratio [RR], 0.79 per 1-g/dL [10-g/L] increase; 95% confidence interval [CI], 0.65 to 0.95; P = 0.015), male sex (P = 0.003), and being dialyzed in the Veterans Administration (RR, 1.97; 95% CI, 1.48 to 2.62; P < 0.001) or other center (RR, 1.68; 95% CI, 1.92 to 5.62; P < 0.001). Although CCI score correlated inversely with albumin level (r = -0.305; P < 0.001), CCI score was only marginally predictive of peritonitis (P = 0.068). In multivariate analysis, predictors were albumin level (RR, 0.74; 95% CI, 0.31 to 1.75; P = 0.002) and race (RR, 1.36; P = 0.024). Patients with an initial serum albumin level less than 2.9 g/dL (29 g/L) had a peritonitis rate of 1.5 episodes/dialysis-year compared with 0.6 episodes/dialysis-year for patients with an initial serum albumin level of 2.9 g/dL or greater (P < 0.001). CONCLUSION: Hypoalbuminemia at the start of PD therapy is an independent predictor of subsequent peritonitis. Intervention studies to decrease peritonitis risk in this high-risk subset of patients are needed.

Adult↗
PubMed2003

Inhibitory effects on mushroom tyrosinase by some alkylbenzaldehydes.

The inhibition kinetics on the diphenolase activity of mushroom tyrosinase by some alkylbenzaldehydes has been investigated. The results show that the alkylbenzaldehydes assayed can lead to reversible inhibition to the enzyme; o-tolualdehyde and m-tolualdehyde are mixed-type inhibitors and p-alkylbenzaldehydes are uncompetitive inhibitors. For the p-alkylbenzaldehydes, the inhibition potency follows the order: p-tolualdehyde < p-ethylbenzaldehyde < p-propylbenzaldehyde = p-Isopropylbenzaldehyde < p-tert-butylbenzaldehyde = p-butylbenzaldehyde < p-pentylbenzaldehyde < p-hexylbenzaldehyde > p-heptylbenzaldehyde > p-octylbenzaldehyde, indicating the hydrophobic p-alkyl group played an important role in inhibition to the enzyme. The inhibitory effects of alkylbenzaldehydes on the monophenolase activity have also been studied. The results show that o-tolualdehyde and m-tolualdehyde can lengthen the lag time and decrease the steady-state activity of the enzyme, but p-alkylbenzaldehydes only decrease the steady-state activity and do not lengthen the lag time, indicating that their inhibitory mechanisms are different.

Agaricales↗
PubMed2003

[Prevention of enamel demineralization adjacent to orthodontic brackets bonded with resin-modified glass ionomer: an in vitro pH cycling study].

OBJECTIVE: To investigate the resin-modified glass ionomer cement for inhibition of enamel demineralization adjacent to orthodontic brackets under a pH cycling experiment. METHODS: The study used 5 pairs of extracted human premolars. The experiment teeth were bonded with resin-modified glass ionomer, the control teeth were bonded with composite resin. All samples were under the pH cycling experiment each day for 60 days. Demineralization lesions of enamel adjacent to orthodontic brackets were evaluated with polarized light microscopy. The depth and area of the lesion, and the distance between the edge of the adhesive on the enamel surface and the border of the lesion were measured. RESULTS: The depth and area of lesions of control were greater than those of experiment group were. Paired t test showed significant differences (p < 0.001). There was always a distance between the lesions border and the glass ionomer cement. In control group, all lesions were developed under the edge of composite resin. CONCLUSION: It was suggested that resin-modified glass ionomer may become an orthodontic bonding agent to minimize enamel demineralization.

Glass Ionomer Cements↗