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Biomedical subjects

Wei Zhou

Publications and source records attributed to Wei Zhou.

At least 163 records · Page 9Linked to original sources

[Filter-based template preparation for rapid and sensitive PCR detection of Staphylococcus aureus in meat].

In the present study, an assay using Polymerase Chain Reaction (PCR) was developed for the detection of Staphylococcus aureus in meat. Based on flotation and solvent extraction technology, FTA filter was used to extract S. aureus DNA from artifically contaminated meat. Primers targeting the thermostable nuclease gene (nuc) were used to amplify a 279 bp DNA fragment which was confirmed by DNA sequencing. The detection limit of PCR was 10 cfu x g(-1) meat of S. aureus. This novel FTA-PCR assay allows for detection of Staphylococcus aureus in meat in <6 h, which is 12-24 h less than that of conventional PCR with enrichment method. Seventy-two samples were analyzed and the detection rate using the standard cultivation method was 70.8%, detection time was 5d. The detection rate of PCR amplification using filters was 73.6%, detection time was 6h. The detection rate of Baird-Parker R.P.F method was 69.4%, detection timewas 18 h. The detection rate of petrfilm RSA method was 61.1%, detection time was 18 h. Thus PCR amplification using filters provides a faster and more sensitive method of S. aureus detection than the standard cultivation method. At the same time,it provides an universal process for preparing DNA template.

Animals↗

Impaired arachidonic acid-mediated dilation of small mesenteric arteries in Zucker diabetic fatty rats.

Arachidonic acid (AA) is a precursor of important vasoactive metabolites, but the role of AA-mediated vasodilation in Type 2 diabetes is not known. Using Zucker diabetic fatty (ZDF) rats, we examined the effects of AA in small mesenteric arteries preconstricted with endothelin. In ZDF rat mesenteric arteries, 1 microM AA produced only one-third the amount of dilation as in vessels from lean control animals. In lean control rats, the effect of AA was significantly and predominantly inhibited by the lipoxygenase inhibitors baicalein and cinnamyl-3,4-dihydroxy-cyanocinnamate (CDC). However, baicalein and CDC had no effect on AA-mediated dilation in ZDF rat mesenteric arteries. The major [3H]AA metabolite produced by isolated mesenteric arteries in both lean and ZDF rats was 12-hydroxyeicosatetraenoic acid (12-HETE), but the amount of [3H]12-HETE produced by ZDF rat vessels was only 36% of that of control vessels. In addition, 12-HETE produced similar amounts of dilation in lean and ZDF rat mesenteric arteries. Immunoblot analysis showed an 81% reduction in 12-lipoxygenase protein in ZDF rat mesenteric arteries. Immunofluorescence labeling showed strong nitrotyrosine signals in ZDF rat mesenteric arteries that colocalized with 12-lipoxygenase in endothelium, and 12-lipoxygenase coprecipitation with anti-nitrotyrosine antibodies was enhanced in ZDF rat vessels. We conclude that AA-mediated relaxation in ZDF rat small mesenteric arteries is impaired due to reduced 12-lipoxygenase protein and activity. Increased oxidative stress and nitration of 12-lipoxygenase may underlie the impairment of AA-mediated relaxation in small mesenteric arteries of diabetic rats.

12-Hydroxy-5,8,10,14-eicosatetraenoic Acid↗

The SOD2 Val/Val genotype enhances the risk of nonsmall cell lung carcinoma by p53 and XRCC1 polymorphisms.

BACKGROUND: Exogenous reactive oxygen species (ROS) induces DNA damage. Manganese superoxide dismutase (SOD2) catalyzes the dismutation of superoxide radicals, a major type of ROS, into hydrogen peroxide. p53 is a tumor suppressor gene, and X-ray cross-complementing group 1 (XRCC1) is involved in the base-excision repair of ROS-induced DNA damage. METHODS: The authors investigated whether the SOD2 Ala16Val polymorphism modifies the associations between p53 Arg72Pro and XRCC1 Arg399Gln polymorphisms and the risk of nonsmall cell lung carcinoma (NSCLC) in a case-control study of 935 Caucasian patients with NSCLC and 1233 healthy control participants. The results were analyzed using logistic regression models that were adjusted for possible confounding variables. RESULTS: There was no association between p53 or XRCC1 polymorphism and NSCLC risk for individuals with SOD2 Ala/Ala or Ala/Val genotype. For individuals with the SOD2 Val/Val genotype, greater risks were found in association with p53 (variant Pro allele vs. Arg/Arg), XRCC1 (variant Gln allele vs. Arg/Arg), and the combination of the two polymorphisms ("double variant" vs. "double wild type"), with the adjusted odds ratios (ORs) of 1.84 (95% confidence interval [95% CI], 1.20-2.82), 1.39 (95% CI, 0.98-2.21), and 2.54 (95% CI, 1.38-4.68), respectively. Furthermore, the greater risk for the double variant of p53 and XRCC1 in the SOD2 Val/Val genotype group was specific only for patients with adenocarcinoma and not for patients with squamous cell carcinoma, with adjusted ORs of 3.31 (95% CI, 1.68-6.51) and 0.69 (95% CI, 0.24-2.02), respectively. CONCLUSIONS: The SOD2 Val/Val genotype may increase the risk of NSCLC carried by XRCC1 and p53 polymorphisms, particularly for adenocarcinoma.

Adult↗

Effective induction of antitumor immunity by immunization with plasmid DNA encoding TRP-2 plus neutralization of TGF-beta.

Plasmid DNA vaccine is an appealing cancer immunotherapy. However, it is a weak immunogen and immunization with plasmid DNA encoding self-antigens, such as melanoma-associated antigens, could not induce antitumor immunity because of tolerance. In this study, we investigated the feasibility of using a plasmid DNA encoding Xenopus laevis transforming growth factor-beta 5 (aTGF-beta5) as an immunogen to induce neutralizing antibodies against murine TGF-beta1 (mTGF-beta1) and thus enhance the efficacy of plasmid DNA vaccine encoding murine tyrosinase-related protein 2 (mTRP-2) through neutralization of TGF-beta. The results showed that immunization with aTGF-beta5 resulted in the generation of mTGF-beta1-neutralizing antibodies, and immunization with a combination of aTGF-beta5 and mTRP-2 induced specific cytotoxic T lymphocytes (CTLs). On the contrary, immunization with mTRP-2 alone could not elicit the CTL response. Moreover, immunization of C57BL/6 wild-type mice with a combination of aTGF-beta5 and mTRP-2 induced the protective and therapeutic antitumor immunity to B16F10 melanoma, whereas the antitumor activity was abrogated in both CD4-deficient mice and CD8-deficient mice on the C57BL/6 background. Our results indicate that immunization with aTGF-beta5 is capable of breaking immune tolerance and induces mTGF-beta1-neutralizing antibodies. Neutralization of TGF-beta can enhance the efficacy of DNA vaccine encoding mTRP-2 and the induction of antitumor immunity by this immunization strategy is associated with CD4+ and CD8+ T cells.

Animals↗

Afferent mechanisms underlying stimulation modality-related modulation of acupuncture-related cardiovascular responses.

Despite the use of acupuncture to treat a number of heart diseases, little is known about the mechanisms that underlie its actions. Therefore, we examined the influence of acupuncture on sympathoexcitatory cardiovascular responses to gastric distension in anesthetized Sprague-Dawley rats. Thirty minutes of low-current, low-frequency, (0.3-0.5 mA, 2 Hz) electroacupuncture (EA), at P 5-6, S 36-37, and H 6-7 overlying the median, deep peroneal, and ulnar nerves significantly decreased reflex pressor responses by 40, 39, and 44%, respectively. In contrast, sham acupuncture involving needle insertion without stimulation at P 5-6 or 30 min of EA at LI 6-7 acupoints overlying the superficial radial nerve did not attenuate the reflex. Similarly, EA at P 5-6 using 40- or 100-Hz stimulation frequencies did not inhibit the reflex. Compared with EA at P 5-6, EA at two sets of acupoints, including P 5-6 and S 36-37, did not lead to larger inhibition of the reflex. Two minutes of manual acupuncture (MA; 2 Hz) at P 5-6 every 10 min for 30 min inhibited the reflex cardiovascular pressor response by 33%, a value not significantly different from 2-Hz EA at P 5-6. Single-unit afferent activity was not different between electrical stimulation (ES) and manual stimulation. However, 2-Hz ES activated more somatic afferents than 10- or 20-Hz ES. These data suggest that, although the location of acupoint stimulation and the frequency of stimulation determine the extent of influence of EA, there is little difference between low-frequency EA and MA at P 5-6. Furthermore, simultaneous stimulation using two acupoints that independently exert strong effects did not lead to an additive or a facilitative interaction. The similarity of the responses to EA and MA and the lack of cardiovascular response to high-frequency EA appear to be largely a function of somatic afferent responses.

Acupuncture↗

Microsomal epoxide hydrolase, endotoxin, and lung function decline in cotton textile workers.

Occupational exposure to endotoxin in organic dust may induce lung function decline. Microsomal epoxide hydrolase (mEH) detoxifies reactive oxygen species generated by endotoxin exposure, and polymorphisms of the mEH gene are associated with altered enzyme activity. We investigated the associations between mEH polymorphisms, endotoxin exposure, and lung function decline in a 20-year prospective study of 265 workers exposed to endotoxin and 234 control subjects. mEH Tyr113His and His139Arg polymorphisms were genotyped by the 5' nuclease assay, and data were analyzed using multivariate linear regression models, adjusting for important covariates. Overall, the annual decline rate of FEV1 was 29.47 ml during the 20-year follow-up. Endotoxin exposure was associated with faster lung function decline among genotypes associated with slower enzyme activity: estimates (SE) of annual FEV1 decline rates for endotoxin exposure were -2.33 (2.07), -2.81 (1.66), and -6.73 (2.83) ml for Tyr/Tyr, Tyr/His, and His/His genotype groups, respectively, for the Tyr113His polymorphism; and -1.82 (2.58) and -4.27 (1.33) ml for Arg/Arg + His/Arg and His/His genotypes, respectively, for the His139Arg polymorphism. We conclude that mEH polymorphisms modify the association between occupational endotoxin exposure and longitudinal lung function decline.

Case-Control Studies↗

MPO and SOD2 polymorphisms, gender, and the risk of non-small cell lung carcinoma.

Manganese superoxide dismutase (SOD2) and myeloperoxidase (MPO) are polymorphic enzymes involved in reactive oxidative species metabolism. In this case-control study (830 non-small cell lung carcinoma (NSCLC) patients; 1119 controls) we evaluated whether the MPO -G463A polymorphism (associated with a novel estrogen receptor binding site) modifies the association between the SOD2 Ala16Val polymorphism and NSCLC risk differently by gender. For women carrying the MPO variant genotypes, the adjusted odds ratio of the SOD2 polymorphism (Val/Val vs. Ala/Ala) was 3.26 (95% CI, 1.55-6.83). No associations were found in men or in women carrying the MPO GG wildtype genotype.

Adult↗

Surgical margin and Gleason score as predictors of postoperative recurrence in prostate cancer with or without chromosome 8p allelic imbalance.

BACKGROUND: Identification of prostate cancer patients at risk for postoperative disease recurrence is an important clinical issue. Existing pathological markers can predict disease recurrence only to a certain extent, and there is a need for more accurate predictors. METHODS: Using "counting alleles," a novel experimental method, we determined allelic status of chromosome 8p in 107 prostatectomy specimens. Statistical analyses examined the association between pathologic predictors (Gleason score, stage, surgical margin, etc.) and cancer recurrence in patients with and without 8p allelic imbalance (8p AI). RESULTS: 8p AI cancers were more likely to recur in the presence of a positive surgical margin, whereas recurrence of 8p retaining tumors was associated with the Gleason score, but not with the surgical margin. CONCLUSIONS: Our findings suggest that chromosome 8p allelic status affects the predictive value of "traditional" markers of prostate cancer recurrence. If confirmed by larger studies, these results may have important clinical implications.

Age Factors↗

Macroscopic, neat, single-walled carbon nanotube fibers.

Well-aligned macroscopic fibers composed solely of single-walled carbon nanotubes (SWNTs) were produced by conventional spinning. Fuming sulfuric acid charges SWNTs and promotes their ordering into an aligned phase of individual mobile SWNTs surrounded by acid anions. This ordered dispersion was extruded via solution spinning into continuous lengths of macroscopic neat SWNT fibers. Such fibers possess interesting structural composition and physical properties.

Journal Article↗

Activation of rat mesenteric arterial KATP channels by 11,12-epoxyeicosatrienoic acid.

Epoxyeicosatrienoic acids (EETs), the cytochrome P-450 epoxygenase metabolites of arachidonic acid, are candidates of endothelium-derived hyperpolarizing factors. We have previously reported that EETs are potent activators of cardiac ATP-sensitive K(+) (K(ATP)) channels, but their effects on the vascular K(ATP) channels are unknown. With the use of whole cell patch-clamp techniques with 0.1 mM ATP in the pipette and holding at -60 mV, freshly isolated smooth muscle cells from rat mesenteric arteries had small glibenclamide-sensitive currents at baseline (13.1 +/- 3.9 pA, n = 5) that showed a 7.2-fold activation by 10 microM pinacidil (94.1 +/- 21.9 pA, n = 7, P < 0.05). 11,12-EET dose dependently activated the K(ATP) current with an apparent EC(50) of 87 nM. Activation of the K(ATP) channels by 500 nM 11,12-EET was inhibited by inclusion of the PKA inhibitor peptide (5 microM) but not by the inclusion of the PKC inhibitor peptide (100 microM) in the pipette solution. These results were corroborated by vasoreactivity studies. 11,12-EET produced dose-dependent vasorelaxation in isolated small mesenteric arteries, and this effect was reduced by 50% with glibenclamide (1 microM) preincubation. The 11,12-EET effects on vasorelaxation were also significantly attenuated by preincubation with cell-permeant PKA inhibitor myristoylated PKI(14-22), and, in the presence of PKA inhibitor, glibenclamide had no additional effects. These results suggest that 11,12-EET is a potent activator of the vascular K(ATP) channels, and its effects are dependent on PKA activities.

8,11,14-Eicosatrienoic Acid↗

Excision repair cross-complementation group 1 polymorphism predicts overall survival in advanced non-small cell lung cancer patients treated with platinum-based chemotherapy.

DNA repair is a critical mechanism of resistance to platinum-based chemotherapy. Excision repair cross-complementation group 1 (ERCC1) is the lead enzyme in the nucleotide excision repair process. Increased ERCC1 mRNA levels are related directly to platinum resistance in various cancers. We examined the association between two polymorphisms of ERCC1, codon 118 C/T and C8092A, which are associated with altered ERCC1 mRNA levels and mRNA stability, and overall survival (OS) in 128 advanced non-small cell lung cancer patients treated with platinum-based chemotherapy. The two polymorphisms were in linkage disequilibrium. There was a statistically significant association between the C8092A polymorphism and OS (P = 0.006, by log-rank test), with median survival times of 22.3 (C/C) and 13.4 (C/A or A/A) months, respectively, suggesting that any copies of the A allele were associated with poor outcome. No statistically significant association was found for the codon 118 polymorphism and OS (P = 0.41, by log-rank test), with median survival times of 19.9 (T/T), 16.1 (C/T), and 13.3 (C/C) months, respectively. In conclusion, the ERCC1 C8092A polymorphism may be a useful predictor of OS in advanced non-small cell lung cancer patients treated with platinum-based chemotherapy.

Adult↗

Molecular mechanisms and clinical applications of ginseng root for cardiovascular disease.

Ginseng root is used extensively in traditional Chinese medicine for its alleged tonic effect and possible curative and restorative properties. There are increasing evidences in the literature on the potential role of ginseng in treating cardiovascular diseases. We herein examine the history of ginseng usage and review the current literature on a myriad pharmacological function of ginseng on the cardiovascular system. From the published studies involving cell cultures and animal models, ginseng is shown to have potential benefits on the cardiovascular system through diverse mechanisms, including antioxidant, modifying vasomotor function, reducing platelet adhesion, influencing ion channels, altering autonomic neurotransmitters release, improving lipid profiles, and involving in glucose metabolism and glycemic control. In addition, the relevant clinical trials regarding the effects of ginseng on the cardiovascular disease are summarized, particularly in managing hypertension and improving cardiovascular function. Finally, the controversies in the literature and the possible adverse interactions between ginseng and other drugs are discussed. This review underscores the potential benefit effects of ginseng on cardiovascular diseases, highlights the gaps in our current research, and emphasizes the necessity for more rigorous systemic investigation.

Antioxidants↗

Therapeutic polypeptides based on HBV core 18-27 epitope can induce CD8+ CTL-mediated cytotoxicity in HLA-A2+ human PBMCs.

AIM: To explore how to improve the immunogenicity of HBcAg CTL epitope based polypeptides and to trigger an HBV-specific HLA I-restricted CD8+ T cell response in vitro. METHODS: A new panel of mimetic therapeutic peptides based on the immunodominant B cell epitope of HBV PreS2 18-24 region, the CTL epitope of HBcAg18-27 and the universal T helper epitope of tetanus toxoid (TT) 830-843 was designed using computerized molecular design method and synthesized by Merrifield's solid-phase peptide synthesis. Their immunological properties of stimulating activation and proliferation of lymphocytes, of inducing T( H1) polarization, CD8+ T cell magnification and HBV-specific CD8+ CTL mediated cytotoxicity were investigated in vitro using HLA-A2+ human peripheral blood mononuclear cells (PBMCs) from healthy donors and chronic hepatitis B patients. RESULTS: Results demonstrated that the therapeutic polypeptides based on immunodominant HBcAg18-27 CTL, PreS2 B- and universal T(H) epitopes could stimulate the activation and proliferation of lymphocytes, induce specifically and effectively CD8+ T cell expansion and vigorous HBV-specific CTL-mediated cytotoxicity in human PBMCs. CONCLUSION: It indicated that the introduction of immunodominant T helper plus B-epitopes with short and flexible linkers could dramatically improve the immunogenicity of short CTL epitopes in vitro.

Amino Acid Sequence↗

Electrochemical control of CO/NO ligand exchange in a triruthenium cluster monolayer assembled on a gold electrode surface.

A highly selective ligand exchange reaction is realized in the self-assembled monolayer (SAM) of a triruthenium cluster on a gold electrode surface under precise electrochemical potential control. CO as well as NO molecules, which are known to play key roles in many chemical, biological, and environmental systems, can be efficiently introduced into the SAM by electrochemically tuning the electronic state of the Ru site. These unique surface reactions are more convenient and efficient than conventional ligand exchange reactions in solution and could be used for the elucidation of the electron-transfer mechanism in a biological system as well as in the development of molecular sensors and devices.

Carbon Monoxide↗

[Role of NF-kappa B in cancer cachexia].

OBJECTIVE: To assess the putative involvement of NF-kappaB and pro-inflammatory cytokines in the pathogenesis of cancer cachexia and the therapeutic efficacy of indomethacin (IND) on cachexia. METHODS: Thirty young male BALB/c mice were divided randomly into five groups: A, control; B, tumor-bearing plus saline; C, tumor-bearing plus IND (0.25 mg/kg); D, tumor-bearing plus IND (0.5 mg/kg); and E, tumor-bearing plus IND (2.0 mg/kg). Colon 26 adenocarcinoma cells of murine were inoculated subcutaneously to induce cachexia. Saline and IND were given intraperitoneally daily for 7 days from the onset of cachexia to sacrifice. Food intake and body composition were documented, serum TNF-alpha and IL-6 levels and activity of NF-kappaB in spleen were investigated in all animals. RESULTS: Cachexia was observed in all tumor-bearing mice. No difference was found between groups in food intake (P > 0.05). By day 16, body weights of non-tumor mice were about 82.0% of healthy controls (P < 0.01), and the weight of gastrocnemius was decreased by 28.7% (P < 0.01). Gastrocnemius weight was increased markedly (P < 0.01) after treatment of IND (0.5 mg/kg). Tumor-bearing caused a significant increase in serum TNF-alpha and IL-6 levels (P < 0.01). The concentration of TNF-alpha (P < 0.05) and IL-6 (P < 0.01) in tumor-bearing mice was reduced after administration of 0.5 mg/kg IND for 7 days. NF-kappaB activation in the spleen was increased in tumor-bearing mice in comparison with controls. NF-kappaB activity was reduced in mice treated with IND. The maximal inhibition was observed at an dosage of 0.5 mg/kg (P < 0.01). Liner positive correlation was found between NF-kappaB activity and cytokine levels (r(TNF-alpha) = 0.918, P(TNF-alpha) = 0.028; r(IL-6) = 0.884, P(IL-6) = 0.046). CONCLUSIONS: Cachexia induced by colon 26 adenocarcinoma cells may be partially attributed to the enhanced TNF-alpha and IL-6 levels which is controlled by NF-kappaB. IND may inhibit the activation of NF-kappaB, decrease serum TNF-alpha and IL-6 levels and thus alleviate the cachexia.

Adenocarcinoma↗

XPD and XRCC1 genetic polymorphisms are prognostic factors in advanced non-small-cell lung cancer patients treated with platinum chemotherapy.

PURPOSE: Platinum agents cause DNA cross-linking and oxidative damage. Genetic polymorphisms of DNA repair genes are associated with differential DNA repair activity and may explain interindividual differences in overall survival after therapy with platinum agents for non-small-cell lung cancer (NSCLC). METHODS: We used polymerase chain reaction-restriction fragment length polymorphism to evaluate genetic polymorphisms of the XPD (Asp312Asn) and XRCC1 (Arg399Gln) DNA repair genes in 103 patients with stage III (54%) and IV (46%) NSCLC treated with platinum-based chemotherapy. RESULTS: Median age was 58 years (range, 32 to 77 years), 49% were females, and there were 86 deaths. Median follow-up period was 61.9 months. Median survival time (MST) was 14.9 months; by stage, MST was 28.6 months (IIIA), 16.0 months (IIIB), and 9.3 months (IV). Genotypes were not associated with stage. Increasing numbers of either XPD or XRCC1 variant alleles were associated with shorter overall survival (P =.003 and P =.07, respectively, by log-rank test). Similarly, when we compared combinations of variant alleles across both polymorphisms, we found that a greater number of variant alleles was associated with decreasing overall survival (P =.009, log-rank test). These polymorphisms independently predicted overall survival even after taking into account stage, performance status, and chemotherapy regimen. CONCLUSION: Genetic polymorphisms in XPD and XRCC1 may be important prognostic factors in platinum-treated patients with advanced NSCLC.

Adult↗

Therapeutic polypeptides based on HBcAg(18-27) CTL epitope can induce antigen-specific CD(8)(+) CTL-mediated cytotoxicity in HLA-A2 transgenic mice.

AIM: To explore how to trigger an HLAI-restricted CD8(+) T cell response to exogenously synthesized polypeptides in vivo. METHODS: Three mimetic therapeutic polypeptides based on the immunodominant CTL epitope of HBcAg, the B- epitope of HBV PreS(2) region and a common T helper sequence of tetanus toxoid were designed and synthesized with Merrifield's solid-phase peptide synthesis method. Their immunological properties of inducing T( H1) polarization, CD8(+) HBV-specific CTL expansion and CD8(+) T cell mediated cytotoxicity were investigated in HLA-A2 transgenic mice. RESULTS: Results demonstrated that the mimetic polypeptides comprised of the immunodominant CTL, B-, and T helper epitopes could trigger specifically and effectively vigorous CD8(+) HBV-specific CTL-mediated cytotoxicity and T(H1) polarization of T cells in HLA-A2 transgenic mice. CONCLUSION: A designed universal T helper plus B-epitopes with short and flexible linkers could dramatically improve the immunogenicity of CTL epitopes in vivo. And that the mimetic therapeutic peptides based on the reasonable match of the above CTL, B- and T helper epitopes could be a promising therapeutic peptide vaccine candidate against HBV infection.

Animals↗

A voltage-gated calcium-selective channel encoded by a sodium channel-like gene.

BSC1, which was originally identified by its sequence similarity to voltage-gated Na(+) channels, encodes a functional voltage-gated cation channel whose properties differ significantly from Na(+) channels. BSC1 has slower kinetics of activation and inactivation than Na(+) channels, it is more selective for Ba(2+) than for Na(+), it is blocked by Cd(2+), and Na(+) currents through BSC1 are blocked by low concentrations of Ca(2+). All of these properties are more similar to voltage-gated Ca(2+) channels than to voltage-gated Na(+) channels. The selectivity for Ba(2+) is partially due to the presence of a glutamate in the pore-forming region of domain III, since replacing that residue with lysine (normally present in voltage-gated Na(+) channels) makes the channel more selective for Na(+). BSC1 appears to be the prototype of a novel family of invertebrate voltage-dependent cation channels with a close structural and evolutionary relationship to voltage-gated Na(+) and Ca(2+) channels.

Amino Acid Sequence↗