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Biomedical subjects

Hui Wang

Publications and source records attributed to Hui Wang.

At least 289 records · Page 16Linked to original sources
PubMed2004

Cellular automata modeling of pedestrian's crossing dynamics.

Cellular automata modeling techniques and the characteristics of mixed traffic flow were used to derive the 2-dimensional model presented here for simulation of pedestrian's crossing dynamics. A conception of "stop point" is introduced to deal with traffic obstacles and resolve conflicts among pedestrians or between pedestrians and the other vehicles on the crosswalk. The model can be easily extended, is very efficient for simulation of pedestrian's crossing dynamics, can be integrated into traffic simulation software, and has been proved feasible by simulation experiments.

Accidents, Traffic↗
PubMed2004

Wnt/beta-catenin signaling pathway as a novel cancer drug target.

Wnt proteins are a large family of secreted glycoproteins. Wnt proteins bind to the Frizzled receptors and LRP5/6 co-receptors, and through stabilizing the critical mediator beta-catenin, initiate a complex signaling cascade that plays an important role in regulating cell proliferation and differentiation. Deregulation of the canonical Wnt/beta-catenin signaling pathway, mostly by inactivating mutations of the APC tumor suppressor, or oncogenic mutations of beta-catenin, has been implicated in colorectal tumorigenesis. Although oncogenic mutations of beta-catenin have only been discovered in a small fraction of non-colon cancers, elevated levels of beta-catenin protein, a hallmark of activated canonical Wnt pathway, have been observed in most common forms of human malignancies, indicating that activation of this pathway may play an important role in tumor development. Over the past 15 years, our understanding of this signaling pathway has significantly improved with the identification of key regulatory proteins and the important downstream targets of beta-catenin/Tcf transactivation complex. Given the fact that Wnt/beta-catenin signaling is tightly regulated at multiple cellular levels, the pathway itself offers ample targeting nodal points for cancer drug development. In this review, we discuss some of the strategies that are being used or can be explored to target key components of the Wnt/beta-catenin signaling pathway in rational cancer drug discovery.

Animals↗
PubMed2004

Recent advances in experimental molecular therapeutics for malignant gliomas.

The current lack of effective therapy for malignant gliomas has prompted the development of three primary foci of molecular research: anti-angiogenesis therapy, immunotherapy, and DNA- and RNA-based therapies. Angiogenesis inhibitors, designed to exploit the highly vascularized nature of gliomas, target endothelial cells and/or the extracellular matrix and bypass many of the problems of conventional chemotherapy. There may be easy access to the molecular target (e.g. blood vessels), reduced induction of drug resistance, and general lack of host toxicity. The relatively immunoprivileged status of the brain has also prompted use of immune stimulation as an anti-glioma strategy. Lines of attack include global cytokine therapy, vaccination with specific tumor antigens, dosing with monoclonal antibodies conjugated to radioisotopes or toxins, and ex vivo priming of lymphocytes. With regard to DNA- and RNA-based therapy, numerous oncogenic proteins have been targeted by antisense molecules administered alone or in combination with conventional chemotherapy and radiation. In one tactic, termed "suicide" gene therapy, herpes simplex thymidine kinase has been transfected into glioma cells via a retrovirus; subsequent introduction of ganciclovir causes cytotoxicity in the transduced cells. Although considerable preclinical data have been accumulated, promising results for therapy of human glioma have only recently appeared.

Angiogenesis Inhibitors↗
PubMed2004

[Follow-up study of mental developments in high-risk children].

OBJECTIVE: To study the mental developments in high risk children and the impact of the high risk factors on neurologic abnormalities, mental defect and long-term outcome. METHODS: The mental development of 122 children who had been exposed to high-risk factors and treated between March 1994 to May 1995 during their newborn periods was evaluated. Gesell development scales were performed when they were at 6 and 12 months old. And Wechsler intelligence scales for children (Chinese version) were performed at 6 approximately 7 years old. RESULTS: The children exposed to hypoglycemia during their newborn period and preterm labor had significantly lower IQ, VIQ and PIQ scores (P <0.05). The other risk factors in order were low birth weight, severe anoxia, asphyxia at birth, erythrocythemia, hyperbilirubinemia. There was significant difference between the children exposed to one risk factor and those exposed to two or more risk factors (P <0.05). And there was significant correlation between developmental assessment at 6 and 12 months and mental development at 6 approximately 7 years old (P<0.01). CONCLUSION: The impact of the high risk factors at birth on children's mental development is not negligible. And the risk of development abnormalities will increase if the children were exposed to multiple risk factors. The evaluation of development at 6 approximately 12 months is of predictive value for long-term outcome.

Apgar Score↗
PubMed2004

Inactivation of Escherichia coli O157:H7 and other naturally occurring microorganisms in apple cider by electron beam irradiation.

Two Escherichia coli O157:H7 strains, SEA 13 B88 gfp 73ec and B6-914 gfp 90ec, together with two bacteria, three yeasts, and two molds that were randomly selected from a collection of microorganisms found on apples or in apple cider, were inoculated into apple cider and subjected to electron beam irradiation at several doses between 0.0 and 2.3 kGy at the Iowa State University Linear Accelerator Facility. The D-values for the E. coli O157:H7 strains ranged between 0.25 and 0.34 kGy; the D-values for most of the normal flora from apples ranged between 0.24 and 0.59 kGy. By taking into account possible variations in treatment conditions, it was calculated that irradiation at 2.47 kGy should achieve a 5-log reduction of E. coli O157:H7 in apple cider at the 95% confidence level. Naturally occurring yeasts might survive such irradiation treatment.

Beverages↗
PubMed2004

[Risk factors and clinical outcomes of nosocomial infections caused by multidrug resistant Pseudomonas aeruginosa].

OBJECTIVE: To investigate the risk factors for multi-drug resistant Pseudomonas aeruginosa (MDRP) infections, and the factors related with poor prognosis of P. aeruginosa infections. METHODS: The data of 44 cases of MDRP nosocomial infections were analyzed from Jan, 1999. to Dec, 2002 in Peking Union Medical Hospital; 68 cases of antibiotic-sensitive P. aeuroginosa infection were randomized as control. T test, chi-square test and Logistic regression analysis were used for statistics. RESULTS: According to univariate analysis, the factors associated with the development of MDRP nosocomial infection were age, APACHE II, co-infection with other pathogens, hospital acquired pneumonia (HAP), mechanical ventilation, COPD, fluoroquinolone and imipenem/meropenem use 15 days before isolation of MDRP. Multivariate logistic regression analysis identified two independent factors: mechanical ventilation and previous imipenem/meropenem use. Of 44 cases of MDRP infections, 24 died, and 20 survived. Univariate analysis revealed that three factors (APACHE II, mechanical ventilation, resistance switch) were associated with clinical prognosis. But a ccording to multivariate logistic regression analysis, only resistance switch was a predictive factor. CONCLUSIONS: Mechanical ventilation and previous imipenem/meropenem use were independent risk factors for MDRP infection. Resistance switch was a predictive factor for the prognosis of MDRP infection.

China↗
PubMed2004

[Effect of cryotherapy and 5-fluorouracil on apoptosis of G422 glioma cells].

BACKGROUND & OBJECTIVE: It was unknown whether the combination of cryotherapy and 5-fluorouracil (5-FU) could produce a synergistic effect, though both of them could induce apoptosis of glioma cells. The aim of this study was to observe the effect of cryotherapy and 5-fluorouracil on apoptosis of G422 glioma cells and to investigate the potential mechanism. METHODS: (1)Experimental mice models with G422 glioma were established. Cryotherapy (-180 degrees C,90s),chemotherapy (5-FU, 18 mg/kg), and cryochemotherapy were performed on them,respectively.(2)TUNEL was used to determine the apoptosis of glioma cells in each group at different time points.(3)The expression of the p53 and the HSP90alpha gene of the frozen glioma were analyzed by immunohistochemical staining. RESULTS: Cryotherapy or 5-FU induced apoptosis of G422 glioma cells, while the combination of cryotherapy and 5-FU remarkably increased the apoptosis rate. The numbers of apoptotic cells of combination group were 30.6+/-11.7, 86.4+/-21.5, 128.1+/-4.1, 237.0+/-30.1, 72.8+/-23.0 at 6h, 12h, 24h, 48h, 72h after cryochemotherapy, respectively, which were significantly higher than those of other groups. There was no expression of HSP90alpha and p53 in the center of freezing area. The p53 and the HSP90alpha proteins increased obviously in the periphery area especially at 48h after freezing compared with control group [(73.1+/-9.3)% vs (60.6+/-9.9)%, (35.6+/-6.6)% vs (13.7+/-6.5)%](P< 0.01). The expression of p53 was positively correlated with expression of HSP90alpha in frozen glioma (r=0.3610, P< 0.01). CONCLUSION: Combination of cryotherapy with 5-FU could enhance the apoptosis of G422 glioma cells presumably through modulating the HSP90alpha and p53 expression pattern. Cryochemotherapy showed better effect than that of cryotherapy or chemotherapy alone.

Animals↗
PubMed2004

[Resistance surveillance of common community respiratory pathogens isolated in China, 2002 - 2003].

OBJECTIVE: To investigate antimicrobial resistance of common community respiratory pathogens isolated in China, 2002 - 2003. METHODS: 779 strains of Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Group A beta-haemolytic Streptococci and oxacillin-susceptible Staphylococcus aureus (MSSA) were isolated from patients with community-acquired respiratory tract infections at 5 hospitals in China from April 2002 to 2003. Meanwhile, 185 strains of S. pneumoniae, H. influenzae and M. catarrhalis were isolated from nasopharynx swabs at 2 day-care centers in Beijing. Agar dilution method was used to determine the minimal inhibitory concentration (MICs) of cefprozil and other 9 antibiotics against these strains. RESULTS: The prevalence of penicillin-intermediate S. pneumoniae (PISP) was 23.9% and that of penicillin-resistant S. pneumoniae (PRSP) was 22.7% at 5 cities in China. The prevalence of PISP were 44.1% in Hangzhou, 26.2% in Wuhan, 21.5% in Shenyang, 20.8% in Shanghai, 18.5% in Beijing, and 12.7% at day-care centers in Beijing;the prevalance of PRSP were 34.9% in day-care centers, 31.9% in Shanghai, 27.9% in Wuhan, 22.1% in Hangzhou, 13.8% in Shenyang and 8.6% in Beijing. The susceptible rate of levofloxacin in S. pneumoniae was 96.3%. 9.5% of H. influenzae and 87.4% of M. catarrhalis produced beta-lactamases. The susceptibility of amoxicillin/clavulanate, cefaclor, cefprozil, cefuroxime, ceftriaxone, azithromycin, and levofloxain in these two species ranged from 96.4% to 100%. The resistance rate of azithromycin in S. pneumoniae was higher than 60%. Cefprozil MICs against PISP, Group A beta-haemolytic Streptococci and MSSA were 4 - 16 fold lower than cefaclor. CONCLUSIONS: Antimicrobial resistance in respiratory pathogens, especially S. pneumoniae is increasing. It brings concerns that high macrolide resistance was found in gram-positive cocci. Cefprozil was more active than cefaclor against respiratory pathogens.

Anti-Bacterial Agents↗
PubMed2004

Toll-like receptor 4 involvement in hepatic ischemia/reperfusion injury in mice.

BACKGROUND: Toll-like receptor 4 (TLR4) is involved in innate immunity by recognizing endotoxin resulting in a burst of inflammatory cascade. We investigated the relation between activation of TLR4 and liver injury in partial hepatic ischemia/reperfusion (I/R) injury in mice. METHODS: TLR4-deficient mice (C3H/Hej) and wild type mice (WT, C3H/Heouj) were used in the model of I/R injury. Partial hepatic ischemia was produced by occlusion of inflow to the median and left lobes for 45 minutes. Blood was drawn at 1 and 3 hours after reperfusion. The blood was analyzed for aspartate aminotransferase (AST) and tumor necrosis factor alpha (TNF-alpha). TNF-alpha mRNA expression and myeloperoxidase (MPO) level in the ischemic lobes were examined by northern blot and myeloperoxidase assay respectively. RESULTS: AST levels were significantly decreased in TLR4deficient mice compared with WT mice at both time points (WT: 1215.5+/-174.03, 2958.17+/-186.81 IU/L at 1 and 3 hours respectively vs TLR4def: 661.83+/-106.09, 1145.17+/-132.43 IU/L at 1 and 3 hours, mean+/-SD, 6 mice/group, t=-6.65 and -5.57, P<0.001). Consistent with the role of TNF-alpha in hepatic I/R, serum TNF-alpha was decreased in TLR4 deficient mice at 3 hours after reperfusion compared with WT (152.39+/-43.3 vs 249.12+/-51.89, n=6, t=-3.13, P<0.05). MPO level in the ischemic lobes in TLR4 deficient mice at 3 hours after reperfusion was significantly lower than that in WT mice (0.059 +/-0.004 vs 0.173+/-0.025, n=6, F=33.49, P<0.001). This difference appears to be mediated at the gene level since TLR4 deficient mice had decreased TNF-alpha mRNA expression at 1 hour after reperfusion compared with WT mice (80.3+/-28.8 vs 189.4+/-24.6, t=-3.25, P<0.05). CONCLUSIONS: Compared with WT mice, TLR4-deficient mice appear to have a mild I/R injury. Regulation of TNF-alpha at mRNA level seems to have a critical effect. These suggest TLR4 be involved in the mechanism of hepatic I/R injury in mice.

Animals↗
PubMed2004

Expression of a novel pyridoxal kinase mRNA splice variant, PKH-T, in human testis.

AIM: To identify the genes specifically expressed in human adult and fetal testes and spermatozoa. METHODS: A human testis cDNA microarray was established. Then mRNAs of human adult and fetal testis and spermatozoa were purified and probes were prepared by a reverse transcription reaction with mRNA as the template. The microarray was hybridized with probes of adult and fetal testes and spermatozoa. The nucleic acid sequences of differentially expressed genes were determined and homologies were searched in the databases of GenBank. RESULTS: A novel human testis-specific gene, PKH-T, was identified by hybridizing adult and fetal testis and spermatozoa probes with a human testis cDNA microarray. The cDNA of PKH-T was 1 069 bp in length. The cDNA sequence of this clone was deposited in the Genbank (AY303972) and PKH-T was also determined as Interim GenSymbol (Unigene, HS.38041). PKH-T contained most PKH conserved motif. The 239 amino acid sequences deduced from the 719 bp open reading frame (ORF) had a homology with the gene PKH (U89606). PKH-T was specifically and strongly expressed in the testis. Comparison of the differential expressions of PKH and PKH-T in testes of different developmental stages indicated that PKH-T was expressed in the adult testis and spermatozoa, while PKH, in the adult, fetal and aged testes. PKH-T had no expression in the testis of Sertoli cell only and partially spermatogenic arrest patients. CONCLUSION: PKH-T is a gene highly expressed in adult human testis and spermatozoa. It may play an important role in spermatogenesis and could be related to male infertility.

Adult↗
PubMed2004

[Survivin antisense oligonucleotide induces lymphoma cells apoptosis and sensitizes the cells to chemotherapy].

OBJECTIVE: To explore the effect of antisense oligodeoxynucleotide (ASODN) of survivin gene on apoptosis and chemotherapy sensitivity of lymphoma cell line Raji. METHODS: Anti-survivin phosphorothioate ASODN was synthesized and transfected into Raji cells by lipofectin. MTT assay was used to detect cytotoxicity. Apoptosis was observed by fluorescence microscopy and flow cytometry. Survivin expression was determined by RT-PCR and Western-blotting. RESULTS: (1) survivin ASODN inhibited the cells proliferation in a dose and time dependent manner. (2) A higher apoptosis rate (33.0%) could be induced in Raji cells by survivin ASODN as compared with that induced by the sense oligodeoxynucleotide (11.5%) (P < 0.05). (3) The expression of survivin mRNA and protein significantly decreased after treatment with survivin ASODN. (4) There was a significant increase of cell inhibition rate after exposure to the combination of survivin ASODN and Vm26 as compared to Vm26 or survivin ASODN alone (both P < 0.05). CONCLUSION: Survivin ASODN is able to inhibit the proliferation of Raji cells, induce the apoptosis, and enhance the sensitivity of Raji cell to chemotherapy via specific down-regulation of survivin expression.

Apoptosis↗
PubMed2004

[Construction of human phage-displayed scFv library and selection of the ScFv against rabies virus].

AIM: To construct a human phage displayed single chain Fv antibody (scFv) library and screen specific scFv against rabies virus. METHODS: Using a phage-display technique, IgVH and IgVL genes were cloned from peripheral blood lymphocytes from three donors immunized with the WISTAR PM strain vaccine. Genes encoding scFv fragments were constructed by random linkage of VH gene and VL gene by SOE PCR, and then the constructed scFv genes were cloned into phagemid vector and transfected into E. coli TG1. The recombinant phages were screened by four rounds of panning with rabies virus vaccine. The positive recombinant phages were sequenced and antigen-binding activity of recombinant scFv was detected by competition ELISA. RESULTS: A human phage-displayed scFv library with about 7 x 10(8) sink size was constructed. A new human scFv was selected, which bound specifically to rabies virus and had higher affinity. CONCLUSION: The results lay a solid foundation for preparation of human engineering antibody to rabies virus reported herein with higher affinity.

Amino Acid Sequence↗
PubMed2004

[Expression of human growth hormone gene in mice and its effect on concentration of murine serum cytokines].

AIM: To explore the effects of high level human growth hormone(GH) on immune function. METHODS: The eukarytic expression plasmid containing hGH gene was constructed and then was injected into musculi quadriceps femoris of mice. 5th, 15th and 25th day after injection, the murine sera were collected and the levels of hGH, IL-2, IFN-gamma and TNF-alpha were detected by ELISA. RESULTS: hGH cDNA was correctly cloned into pcDNA3. COS-1 cells transfected with the recombinant plasmid secreted high level of active hGH. The concentration of hGH in the sera of mice receiving the plasmid was obviously higher than that of control group. However, the concentrations of IL-2, IFN-gamma and TNF-alpha had no significant variation in comparison with those of control group. CONCLUSION: High level GH has no marked effect on secretion of IL-2, IFN-gamma and TNF-alpha.

Animals↗
PubMed2004

[Movement and transformation of nitrate in soil by non-uniform electrokinetics].

Movement and accumulation of nitrate in soil and groundwater has become a serious threat in many cities and agricultural areas. At the same time, application of nitrate as bacterial nitrogenous nutrient in the in-situ bioremediation of some organics-polluted sites is often required. Laboratory experiments were conducted to examine the feasibility of using non-uniform electrokinetics (NUEK) to control the movement of nitrate in unsaturated soil-water system. A natural soil taken from woodland was used as experimental soil. Three electrokinetic processes were tested in bench-scale cells at a constant potential gradient of 1.0 V/cm: unidirectional NUEK, NUEK with periodic polarity-reversal, and conventional uniform electrokinetic (UEK). The tests showed that NUEK drove NO3- through the experimental soil at a rate of 13.5-20 cm/d depending upon the concentration of NO3- and the distribution of electric field density. Compared with UEK, NUEK process more effectively concentrated and retained NO3- close to the anode. Moreover, NUEK process maintained soil characteristics and consumed much less electric energy. Reversal the polarity of NUEK weakened the concentration of NO3- to electrodes, but it stimulated the transformation of NO3- to NO2- and further lowered the electric energy consumption.

Electricity↗
PubMed2004

[Polychlorinated biphenyls residues in eggs of different ages night heron breeding in Yuantouzhu, China].

61 eggs of night heron (Nycticorax nycticorax) were collected in 2000 in Yuantouzhu of Tai lake, China. The breeding birds were divided into three groups by age, namely two, three, four years. The residues of 15 polychlorinated biphenyl congeners in eggs were studied. 15 congeners were found in all egg samples, and PCB118 at the highest level, PCB87, PCB101 and PCB153 at second levels. Total residues of the 4 congeners occupied about 75%-85% of sum 15 congeners residues found in eggs. It was obviously that residues of congeners containing 5-6 chlorine atoms were more than others in eggs. Residues of PCBs in eggs increased with age of breeding birds. The total PCBs concentration in eggs of four years group were higher than that of three years group, two years group by 47.5% and 60.9% respectively. Different from the result of the similar studies in European countries, USA and Japan: the residue of PCB153 is the highest, it was found that in this study the residue of PCB118 is the highest in eggs, which is about 30% of the total PCBs residues, while the PCB153 17% only.

Age Factors↗
PubMed2004

[Preparation and application of monoclonal antibodies against trypsinogen activation peptide].

AIM: To prepare monoclonal antibody against trypsinogen activation peptide(TAP), and develop an immunoassay of TAP for the early diagnosis of acute pancreatitis. METHODS: Chemically synthesized TAP was conjugated to KLH as immunogen to immunize BALB/c mice. The spleen cells were fused with Sp2/0 cells. Clones secreting specific monoclonal antibody were screened by indirect ELISA. After cloning, several hybridoma cell clones stably producing anti-TAP monoclonal antibody were obtained. The mAbs were identified and the detection of TAP concentration by competitive ELISA was established. RESULTS: Ten hybridoma cell clones which could produce monoclonal antibodies to TAP were obtained. The isotypes of the ten mAbs were all IgM, except one (IgG1). Ascites titers were between 1:10(5) to 1:10(6). Specificity analysis proved that all these mAbs reacted only with TAP and had no cross-reaction to bovine serum albumin(BSA), human albumin, trypsinase, amylase. Neutralisation test showed that these mAbs could be evidently neutralized by TAP. A competitive ELISA for the measurement of TAP was developed, with a sensitivity of 0.69 microg/L. The average intra- and inter-assay coefficient of variation (CV) were 9.10% and 10.33% respectively. The median urinary TAP concentration was 57.35 microg/L for acute pancreatitis patients and 9.30 microg/L for controls (P<0.01). CONCLUSION: The mAbs against TAP were prepared successfully and a competitive ELISA method for detecting TAP concentration was established.

Acute Disease↗
PubMed2004

[Effects of almond on D-gal-induced aging rats].

OBJECTIVE: To study the effects of Beijing Almond on D-gal-induced aging rats. METHODS: D-gal-induced aging rats are fed on almond in three different dosages respectively daily (32.5 g/kg feedstuff, 65 g/kg feedstuff, 97.5 g/kg feedstuff). After 30 days, the level of MDA, the activities of SOD, GSH-Px in serum, and the liquid fluidity of erythrocyte membrane were determined. RESULTS: Compared with aging group, the level of MDA in high and middle dose groups decreased significantly (P < 0.01). At the same time, the activities of SOD, GSH-Px and the liquid fluidity of erythrocyte membrane increased evidently (P < 0.01). But the lowest dose group was not significantly difference (P < 0.05). CONCLUSION: Almond in proper has abilities of anti-oxidation and retarding aging process.

Aging↗