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Li WX, Xiao HW, Hong XQ, Niu WX. Predictive value of CK20 in evaluating the efficacy of treatment and prognosis after surgery for colorectal cancer. GENETICS AND MOLECULAR RESEARCH 2015; 14:5823-9. [PMID: 26125781 DOI: 10.4238/2015.may.29.14] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Herein, correlations between expression levels of CK20 and efficacy of treatment and postoperative prognosis of colorectal cancer were evaluated to elucidate the clinical value of CK20. Postoperative follow-up was performed on 62 patients who underwent surgery for colorectal cancer between January 2010 and December 2010. Samples of tumor tissues and intraperitoneal drainage fluids were collected. Blood samples were obtained during the 2-year follow-up period. The expression of CK20 in surgical specimen, intraperitoneal drainage fluids, and postoperative serum samples was quantified by enzyme-linked immunosorbent assay, RT-PCR, and western blotting. Correlation between the levels of CK20 and postoperative outcomes was investigated by Spearman correlation analysis. In both tumor specimens and intraperitoneal drainage fluids, CK20 levels were lower in patients with earlier cancer stages than in those at later stages. During postoperative follow-up, serum negative CK20 patients had significantly higher 3-year survival rates than serum positive CK20 patients. All differences were statistically significant (P < 0.05). CK20 levels can provide clinically valuable information on the postoperative prognosis of patients with colorectal cancer.
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Zhang JC, Zheng GF, Wu L, Ou Yang LY, Li WX. Bone marrow mesenchymal stem cells overexpressing human basic fibroblast growth factor increase vasculogenesis in ischemic rats. ACTA ACUST UNITED AC 2014; 47:886-94. [PMID: 25118628 PMCID: PMC4181224 DOI: 10.1590/1414-431x20143765] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2014] [Accepted: 05/19/2014] [Indexed: 12/20/2022]
Abstract
Administration or expression of growth factors, as well as implantation of autologous
bone marrow cells, promote in vivo angiogenesis. This study
investigated the angiogenic potential of combining both approaches through the
allogenic transplantation of bone marrow-derived mesenchymal stem cells (MSCs)
expressing human basic fibroblast growth factor (hbFGF). After establishing a hind
limb ischemia model in Sprague Dawley rats, the animals were randomly divided into
four treatment groups: MSCs expressing green fluorescent protein (GFP-MSC), MSCs
expressing hbFGF (hbFGF-MSC), MSC controls, and phosphate-buffered saline (PBS)
controls. After 2 weeks, MSC survival and differentiation, hbFGF and vascular
endothelial growth factor (VEGF) expression, and microvessel density of ischemic
muscles were determined. Stable hbFGF expression was observed in the hbFGF-MSC group
after 2 weeks. More hbFGF-MSCs than GFP-MSCs survived and differentiated into
vascular endothelial cells (P<0.001); however, their differentiation rates were
similar. Moreover, allogenic transplantation of hbFGF-MSCs increased VEGF expression
(P=0.008) and microvessel density (P<0.001). Transplantation of hbFGF-expressing
MSCs promoted angiogenesis in an in vivo hind limb ischemia model by
increasing the survival of transplanted cells that subsequently differentiated into
vascular endothelial cells. This study showed the therapeutic potential of combining
cell-based therapy with gene therapy to treat ischemic disease.
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Yeoh WK, Cui XY, Gault B, De Silva KSB, Xu X, Liu HW, Yen HW, Wong D, Bao P, Larson DJ, Martin I, Li WX, Zheng RK, Wang XL, Dou SX, Ringer SP. On the roles of graphene oxide doping for enhanced supercurrent in MgB2 based superconductors. NANOSCALE 2014; 6:6166-6172. [PMID: 24793305 DOI: 10.1039/c4nr00415a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Due to their graphene-like properties after oxygen reduction, incorporation of graphene oxide (GO) sheets into correlated-electron materials offers a new pathway for tailoring their properties. Fabricating GO nanocomposites with polycrystalline MgB2 superconductors leads to an order of magnitude enhancement of the supercurrent at 5 K/8 T and 20 K/4 T. Herein, we introduce a novel experimental approach to overcome the formidable challenge of performing quantitative microscopy and microanalysis of such composites, so as to unveil how GO doping influences the structure and hence the material properties. Atom probe microscopy and electron microscopy were used to directly image the GO within the MgB2, and we combined these data with computational simulations to derive the property-enhancing mechanisms. Our results reveal synergetic effects of GO, namely, via localized atomic (carbon and oxygen) doping as well as texturing of the crystals, which provide both inter- and intra-granular flux pinning. This study opens up new insights into how low-dimensional nanostructures can be integrated into composites to modify the overall properties, using a methodology amenable to a wide range of applications.
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Ye LT, Li WX, Wang WW, Wu SG, Wang GT. Updated morphology, histopathology and molecular phylogeny of Myxobolus hearti, cardiac myxosporea in gibel carp, Carassius gibelio (Bloch). JOURNAL OF FISH DISEASES 2014; 37:11-20. [PMID: 24341506 DOI: 10.1111/jfd.12026] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/29/2011] [Revised: 07/29/2011] [Accepted: 11/07/2011] [Indexed: 06/03/2023]
Abstract
The original description of Myxobolus hearti is supplemented with new data on spore morphology, histopathology and molecular phylogeny. Myxobolus hearti are found in the heart ventricle of the gibel carp, Carassius gibelio (Bloch), where they form whitish oval or irregularly shaped plasmodia. Mature spores are oval or shortly ellipsoidal in frontal view, lemon-shaped in sutural view and eye-shaped in apical view. The spores are 14.12 ± 0.35 (13.6-15) μm long (mean ± SD), 11.85 ± 0.34 ± 0.36 (11-12) μm wide and 7.32 ± 0.36 (7-8) μm thick. The two polar capsules are equal in size, 6.11 ± 0.29 (6-7) μm long and 3.89 ± 0.31(3-4) μm wide, and are long pyriform in shape. Polar filaments have six or seven coils situated perpendicular to the longitudinal axis of the polar capsules. Histopathology indicates that the plasmodia are encased by the host connective tissue, and no inflammatory responses are found in the heart ventricles. Phylogenetic analysis based on the 18S small-subunit ribosomal DNA sequences indicates that M. hearti is, genetically, most similar to Henneguya doneci, a gill-infecting species.
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Xu X, Li WX, Zhang Y, De Silva KSB, Kim JH, Choi S. The effects of graphene doping on the in-field Jc of MgB2 wires. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2012; 12:1402-1405. [PMID: 22629966 DOI: 10.1166/jnn.2012.4641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The field and temperature dependence of the critical current density Jct were measured for both un-doped and graphene doped MgB2/Fe wires manufactured by 99.999% Crystalline Boron and 10% excess Magnesium (99%, 325 mesh). At 4.2 K and 10 T, Jct was estimated to be for the wire sintered at 800 degrees C for 30 minutes, the doped sample is almost improved as one order, compared with the best un-doped sample. At the same time, the temperature dependence of the upper critical field (Hc2) and the irreversibility field (Hirr) for the samples will also be included from the resistance (R)-temperature (T). A significant increase in the upper critical field is the main cause of the enhancement of the critical current density, Jct, in the high field region. The calculated active cross-sectional area fraction (A(F)) represents the connectivity factor between adjacent grains. This value is decreased with wire samples, which is why the improvement of transport Jct is lower than the improvement of magnetic Jcm in diffusion bulk sample.
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Yeoh WK, Gault B, Cui XY, Zhu C, Moody MP, Li L, Zheng RK, Li WX, Wang XL, Dou SX, Sun GL, Lin CT, Ringer SP. Direct observation of local potassium variation and its correlation to electronic inhomogeneity in (Ba(1-x)K(x))Fe2As2 pnictide. PHYSICAL REVIEW LETTERS 2011; 106:247002. [PMID: 21770591 DOI: 10.1103/physrevlett.106.247002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2011] [Indexed: 05/31/2023]
Abstract
Local fluctuations in the distribution of dopant atoms are thought to cause the nanoscale electronic disorder or phase separation in pnictide superconductors. Atom probe tomography has enabled the first direct observations of dopant species clustering in a K-doped 122-phase pnictide. First-principles calculations suggest the coexistence of static magnetism and superconductivity on a lattice parameter length scale over a wide range of dopant concentrations. Our results provide evidence for a mixed scenario of phase coexistence and phase separation, depending on local dopant atom distributions.
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Mao WP, Zhang NN, Zhou FY, Li WX, Liu HY, Feng J, Zhou L, Wei CJ, Pan YB, He ZJ. Cadmium directly induced mitochondrial dysfunction of human embryonic kidney cells. Hum Exp Toxicol 2010; 30:920-9. [DOI: 10.1177/0960327110384286] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Cadmium (Cd) is the major component of polluted environment, which has numerous undesirable effects on health. Cd could induce apoptosis of HEK293 cells, and the mitochondria may play a key role. However, the mode of action is unclear. In the present study, we aimed to evaluate the ability of the Cd to induce dysfunction of mitochondria. We examined the effect of cadmium chloride (1, 5 and 10 μM) on mitochondrial membrane permeability and potential as well as oxidative stress markers in mitochondria isolated from HEK293 cells. We found that Cd could directly increase in permeability and decrease in membrane potential of mitochondria, even resulted in mitochondrial swelling, and that Cd could inhibit the activities of ATPase, lactate dehydrogenase (LDH), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), enhanced the levels of reactive oxygen species (ROS) and lipid peroxidation (LPO). On the whole, the results show that Cd can directly lead to mitochondrial dysfunction of HEK293 cells, including increased permeability, inhibiting respiration and evoking oxidative stress. Thus, for the first time, this paper makes an overall analysis of Cd-induced changes of structure and function of isolated mitochondria. Our findings may also have general implications in Cd-induced apoptosis by mitochondria pathway.
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Li WX, Zeng R, Poh CK, Li Y, Dou SX. Magnetic scattering effects in two-band superconductor: the ferromagnetic dopants in MgB₂. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2010; 22:135701. [PMID: 21389518 DOI: 10.1088/0953-8984/22/13/135701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
This paper demonstrates the magnetic scattering effects on the electron-phonon interaction in two-band superconductors based on the transition-metal-doped MgB₂ to clarify the effects of magnetic dopants on multi-band superconductivity. The phonon properties of polycrystalline Mg(1-x)M(x)B₂ (M = Fe, Ni and Co), with x up to 0.05, were studied, with the investigation based on the normal state Raman spectra, especially the variation of the E(2g) mode. The magnetic scattering effect of Fe is much weaker than that of Mn in MgB₂, while it is stronger than that of Ni. The weak magnetic scattering effects are responsible for the superconducting behaviors of Mg(1 - x)Fe(x)B₂ and Mg(1 - x)Ni(x)B₂. Co shows almost no magnetic scattering effects on the superconductivity, while the depression of the critical temperature, T(c), in Mg(1 - x)Co(x)B₂ is attributed to the phonon behavior and is independent of the ferromagnetic nature of cobalt.
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Sun SL, Wu B, Zhao DY, Zhang XX, Zhang Y, Li WX, Cheng SP. Optimization of Xhhh strain biodegradation with metal ions for pharmaceautical wastewater treatment. JOURNAL OF ENVIRONMENTAL BIOLOGY 2009; 30:877-882. [PMID: 20143722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Effects of three ions, Mn2+, Cu2+ and Zn2+ on biological treatment of pharmaceutical wastewaterby a functional strain Xhhh were investigated. Through orthogonal tests, Cu2+ was determined to be the most important factor influencing Xhhh biodegradation performance. Biodegradation kinetic experiments demonstrated that with Cu+ concentration at about 200 mg l(-1), the maximum of specific growth rate and specific degradation rate were obtained to be 0.033 and 0.075 d(-1), respectively. The optimal levels of Mn2+ (5.00 mg I(-1)), Cu2+ (2.00 mg l(-1)) and Zn2+ (5.00 mg l(-1)) were achieved based on experimental results of their effects on the activities of manganese peroxidase and lignin peroxidase, and biodegradation kinetic parameters. Among three types of biodegradation kinetic models (Monod, Tessier and Contois), Tessier model was found most reasonable for kinetics description of Xhhh growth (R2 = 0.995) and pollutants degradation (R2 = 0.970) in the case of metals optimization. Both kinetics evaluation and experimental results demonstrated that optimization with the three metals made a great contribution to Xhhh growth and COD removal for pharmaceutical wastewater treatment.
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Chen SY, Zhang RD, Feng JG, Xiao H, Li WX, Zan RG, Zhang YP. Exploring factors shaping population genetic structure of the freshwater fish Sinocyclocheilus grahami (Teleostei, Cyprinidae). JOURNAL OF FISH BIOLOGY 2009; 74:1774-1786. [PMID: 20735670 DOI: 10.1111/j.1095-8649.2009.02204.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Phylogeographical analyses on Sinocyclocheilus grahami samples from seven localities within the Lake Dianchi Basin in China were conducted to explore the main factors shaping population structure within this species. Phylogenetic and network analyses revealed two major clades in 24 mtDNA haplotypes. One clade included three haplotypes exclusively from samples of the lower basin and another clade encompassed other haplotypes from samples of the upper basin. The estimated divergence time between the two clades predated the river capture event connecting the lower and upper lake basin and thus supported geographical isolation as the main factor shaping genetic divergence between these two clades. Furthermore, analysis of molecular variance and pair-wise Phi(ST) distances revealed significant genetic differentiation within the upper basin. Mantel tests clearly supported patterns of differentiation arose purely as a result of isolation by distance. These results further highlight the importance of geographical isolation in shaping differentiation within this species.
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Li JG, Li QN, Xu JY, Cai XQ, Liu RL, Li YJ, Ma JF, Li WX. The pulmonary toxicity of multi-wall carbon nanotubes in mice 30 and 60 days after inhalation exposure. JOURNAL OF NANOSCIENCE AND NANOTECHNOLOGY 2009; 9:1384-1387. [PMID: 19441530 DOI: 10.1166/jnn.2009.c162] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The pulmonary toxicity, induced by multi-wall carbon nanotubes in mice, was studied after 30-day and 60-day inhalation exposure. The mice were exposed to multi-wall carbon nanotubes aerosol with weighted mean concentration of 32.61 mg/m3, once in very two days, 6 hours in an exposure day. After 30-day and 60-day inhalation exposure, the pulmonary toxicity of multi-wall carbon nanotubes was assessed using biochemical indices in bronchoalveolar lavage fluid and pathological examination. It was found that the aerosolized multi-wall carbon nanotubes did not induce obvious pulmonary toxicity in 30-day exposure group, but induced severe pulmonary toxicity in 60-day exposure group.
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Wu O, Liu HH, Li WX, Zhang N, Wang Q, Li XP, Dong MX, Zhang XJ, Ye DQ. Serum soluble nucleosome and the broad family of antinucleosome antibodies are associated with organ and tissue damage in systemic lupus erythematosus in a Chinese population. Clin Exp Dermatol 2008; 33:160-3. [PMID: 18257836 DOI: 10.1111/j.1365-2230.2007.02669.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Nucleosomes and the broad family of antinucleosome antibodies (ANAs; anti-double-stranded DNA, antihistone and antinucleosome antibodies) may contribute to the pathogenesis of systemic lupus erythematosus (SLE). We collected clinical information on 90 patients with SLE and 73 healthy volunteers and measured serum levels of the ANA family using a double-sandwich ELISA. The results showed that the levels of serum nucleosomes of patients with SLE was significantly lower and the levels of ANA were significantly higher than healthy controls. Negative correlations between serum nucleosomes and ANA, and positive correlations between individual ANAs were found. Patients with SLE with positive ANA had a significantly higher frequency of renal disorders than those with negative ANA. Determination of serum nucleosomes and ANAs contributes to SLE monitoring.
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63
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Helveg S, Li WX, Bartelt NC, Horch S, Laegsgaard E, Hammer B, Besenbacher F. Role of surface elastic relaxations in an O-induced nanopattern on Pt(110)-(1 x 2). PHYSICAL REVIEW LETTERS 2007; 98:115501. [PMID: 17501062 DOI: 10.1103/physrevlett.98.115501] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2006] [Indexed: 05/15/2023]
Abstract
Scanning tunneling microscopy shows that a nanopattern forms as the Pt(110)-(1 x 2) surface is exposed to oxygen at room temperature or above. The nanopattern consists of [11[over]0] oriented O-induced stripes assembling into a (11 x 2) superstructure at high O coverage. The stripes form because the O adsorption energy increases by expanding the Pt lattice along the ridges of the surface as compared to the bulk. From interplay with density functional theory calculations, we show that the O-induced nanoscale periodicity is caused by short-ranged elastic relaxations confined to the surface.
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64
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Wang JG, Li WX, Borg M, Gustafson J, Mikkelsen A, Pedersen TM, Lundgren E, Weissenrieder J, Klikovits J, Schmid M, Hammer B, Andersen JN. One-dimensional PtO2 at Pt steps: formation and reaction with CO. PHYSICAL REVIEW LETTERS 2005; 95:256102. [PMID: 16384475 DOI: 10.1103/physrevlett.95.256102] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Indexed: 05/05/2023]
Abstract
Using core-level spectroscopy and density functional theory we show that a one-dimensional (1D) oxide structure forms at the steps of the Pt(332) surface after exposure. The 1D oxide is found to be stable in an oxygen pressure range, where bulk oxides are only metastable, and is therefore argued to be a precursor to the Pt oxidation. As an example of the consequences of such a precursor exclusively present at the steps, we investigate the reaction of CO with oxygen covered Pt(332). Albeit more strongly bound, the oxidic oxygen is found to react more easily with CO than oxygen chemisorbed on the Pt terraces.
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65
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Lu R, Maduro M, Li F, Li HW, Broitman-Maduro G, Li WX, Ding SW. Animal virus replication and RNAi-mediated antiviral silencing in Caenorhabditis elegans. Nature 2005; 436:1040-1043. [PMID: 16107851 PMCID: PMC1388260 DOI: 10.1038/nature03870] [Citation(s) in RCA: 316] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2005] [Accepted: 06/06/2005] [Indexed: 12/11/2022]
Abstract
The worm Caenorhabditis elegans is a model system for studying many aspects of biology, including host responses to bacterial pathogens, but it is not known to support replication of any virus. Plants and insects encode multiple Dicer enzymes that recognize distinct precursors of small RNAs and may act cooperatively. However, it is not known whether the single Dicer of worms and mammals is able to initiate the small RNA-guided RNA interference (RNAi) antiviral immunity as occurs in plants and insects. Here we show complete replication of the Flock house virus (FHV) bipartite, plus-strand RNA genome in C. elegans. We show that FHV replication in C. elegans triggers potent antiviral silencing that requires RDE-1, an Argonaute protein essential for RNAi mediated by small interfering RNAs (siRNAs) but not by microRNAs. This immunity system is capable of rapid virus clearance in the absence of FHV B2 protein, which acts as a broad-spectrum RNAi inhibitor upstream of rde-1 by targeting the siRNA precursor. This work establishes a C. elegans model for genetic studies of animal virus-host interactions and indicates that mammals might use a siRNA pathway as an antiviral response.
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Liu ZP, Li WX, Yu B, Huang J, Sun J, Huo JS, Liu CX. Effects of trans-resveratrol from Polygonum cuspidatum on bone loss using the ovariectomized rat model. J Med Food 2005; 8:14-9. [PMID: 15857203 DOI: 10.1089/jmf.2005.8.14] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
trans-Resveratrol (resveratrol) has been shown in several studies to significantly modulate biomarkers of bone metabolism. But, there is no direct evidence supporting its inhibitory effect towards bone loss. In the present study, effects of resveratrol on bone mineral density (BMD) and bone calcium content (BCC) were examined in the ovariectomized (OVX) rat model. Female Wistar rats were divided into four groups: SHAM group (sham-operated), OVX group (OVX control), OVX + ALD group (OVX and treated with 1.0 mg/kg of body weight of alendronate sodium), and OVX + RES group (OVX and treated with 0.7 mg/kg of body weight of resveratrol). Tested materials were given by gavage for 12 weeks after ovariectomy. Results showed that rats in the OVX, OVX + ALD, and OVX + RES groups had significantly higher body weights and feed efficiency than those in the SHAM group (P < .01). The OVX group had significantly lower femoral epiphysis BMD than the SHAM group, and epiphysis BMD in the OVX + ALD and OVX + RES groups was significantly greater than that in the OVX group (P < .05). However, the femoral midpoint BMD was not significantly different among the four groups. Additionally, animals in the OVX group had significantly lower BCC compared with the SHAM group, while the BCC of the OVX + ALD and OVX + RES groups was significantly higher than that of the OVX group (P < .05). These results indicated that resveratrol could increase epiphysis BMD and inhibit the decrease of femur BCC in OVX rats, suggesting that it could play a role in protecting against bone loss induced by estrogen deficiency.
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Yu C, Mao X, Li WX. Inhibition of the PI3K pathway sensitizes fludarabine-induced apoptosis in human leukemic cells through an inactivation of MAPK-dependent pathway. Biochem Biophys Res Commun 2005; 331:391-7. [PMID: 15850772 DOI: 10.1016/j.bbrc.2005.03.182] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2005] [Indexed: 10/25/2022]
Abstract
In the present study, we have investigated the effects of PI3K/Akt pathway on the response of human leukemia cells to fludarabine. Inhibition of PI3K/Akt pathway with a selective inhibitor (e.g., LY294002, or wortmannin) in leukemic cells markedly potentiated fludarabine-induced apoptosis. Inhibition of the PI3K/Akt downstream target mTOR by rapamycin also significantly enhanced fludarabine-induced apoptosis. The co-treatment of fludarabine/LY294002 resulted in significant attenuation in the levels of both phospho-Erk1/2 and phospho-Akt, as well as a marked increase in the level of phospho-JNK. The broad spectrum caspase inhibitor BOC-D-fmk markedly blocked fludarabine/LY-induced apoptosis, had no effect on cytochrome c release to the cytosol, and did abrogate caspase and PARP cleavage. This indicates that mitochondrial dysfunction is upstream of the caspase cascade. Moreover, constitutive activation of the MEK/Erk pathway completely blocked apoptosis induced by the combination of fludarabine/LY294002. Additionally, either constitutive activation of Akt or blockage of the JNK pathway significantly diminished apoptosis induced by the combination. Collectively, these findings demonstrate that inactivation of MAPK, Akt, and activation of the JNK pathway contributes to the induction of apoptosis induced by fludarabine/LY. Comparatively, MAPK inactivation plays a crucial role in fludarabine/LY-induced apoptosis. These results also strongly suggest that combining fludarabine with an inhibitor of the PI3K/Akt/mTOR pathway may represent a novel therapeutic strategy for hematological malignancies.
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Li WX, Osterlund L, Vestergaard EK, Vang RT, Matthiesen J, Pedersen TM, Laegsgaard E, Hammer B, Besenbacher F. Oxidation of Pt(110). PHYSICAL REVIEW LETTERS 2004; 93:146104. [PMID: 15524816 DOI: 10.1103/physrevlett.93.146104] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/04/2004] [Indexed: 05/24/2023]
Abstract
Using scanning tunneling microscopy and temperature programmed desorption we investigate the Pt(110) surface under strongly oxidizing conditions involving either high-pressure O2 or atomic oxygen exposure. At low temperatures, only disordered Pt oxide structures are observed. After annealing ordered surface oxide islands are observed to coexist with a highly stable reconstructed (12x2)-O chemisorption structure. From density functional theory calculations a model for the surface oxide phase is revealed. The phase is found to be metastable, and its presence is explained in terms of stabilizing defects in the chemisorption layer and reduced Pt mobility.
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69
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Africh C, Esch F, Li WX, Corso M, Hammer B, Rosei R, Comelli G. Two-step reaction on a strained, nanoscale segmented surface. PHYSICAL REVIEW LETTERS 2004; 93:126104. [PMID: 15447284 DOI: 10.1103/physrevlett.93.126104] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/16/2004] [Indexed: 05/24/2023]
Abstract
By means of scanning tunneling microscopy and density functional theory calculations we demonstrate that on the Rh(110)-(10 x 2)-O surface, a prototypical multiphase surface of an oxidized transition metal model catalyst, water formation upon H2 exposure is a two-step reaction, with each step requiring special active sites. The 1st step initiates at (2 x 1)p2mg-O defect islands in the (10 x 2) structure and propagates across the surface as a reaction front, removing half of the adsorbed oxygen. The oxygen decorated Rh ridges of the (10 x 2) structure lose their tensile strain upon this reduction step, whereby nanoscale patches of clean Rh become exposed and act as special reaction sites in the 2nd reaction step, which therefore initiates homogeneously over the entire surface.
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Todorova M, Li WX, Ganduglia-Pirovano MV, Stampfl C, Reuter K, Scheffler M. Role of subsurface oxygen in oxide formation at transition metal surfaces. PHYSICAL REVIEW LETTERS 2002; 89:096103. [PMID: 12190418 DOI: 10.1103/physrevlett.89.096103] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2001] [Indexed: 05/23/2023]
Abstract
We present a density-functional theory trend study addressing the incorporation of oxygen into the basal plane of the late 4d transition metals (TMs) from Ru to Ag. Occupation of subsurface sites is always connected with a significant distortion of the host lattice, rendering it initially less favorable than on-surface chemisorption. Penetration starts only after a critical coverage theta(c), which is lower for the softer metals towards the right of the TM series. The computed theta(c) are found to be very similar to those above which the bulk oxide phase becomes thermodynamically more stable, thus suggesting that the initial incorporation of O actuates the formation of a surface oxide on TM surfaces.
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Chen S, Chen G, Cai CC, Wang XM, Guo H, Shen SQ, Wang H, Wu Y, Li GX, Huang J, Li WX, Wei QX, Sun FZ. A study of human DAF, CD59, MCP transgene in xenotransplantation. Transplant Proc 2001; 33:3851-2. [PMID: 11750639 DOI: 10.1016/s0041-1345(01)02630-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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72
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Gou DM, Chow LM, Chen NQ, Jiang DH, Li WX. Construction and characterization of a cDNA library from 4-week-old human embryo. Gene 2001; 278:141-7. [PMID: 11707331 DOI: 10.1016/s0378-1119(01)00701-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Development and differentiation studies of early human embryos have been severely impeded by general difficulties in obtaining suitable samples. In order to isolate and identify new genes expressed during early human development, we constructed and characterized a PCR-based cDNA library using a 4-week-old chorion-free human embryo. The constructed cDNA library contained 6.3 x 10(6) directional recombinants, and its insert size ranged from 0.4 to 1.8 kb. The cDNA library proportionally represents the mRNA population, containing beta-actin, tPA and LINE1 repetitive sequences at the expected frequencies as in other conventionally constructed and PCR-based cDNA libraries. PCR analyses of the library for specific genes have also revealed the presence of cDNAs for developmentally important genes such as CD59, MCP, Quox-1 and ZNF268. Among the 70 randomly selected cDNA clones, 53% encoded previously known genes, 26% matched with anonymous sequences, and 17% showed no sequence similarity and were designated as human early embryo-specific ESTs. These results demonstrate the sequence complexity and relatively low redundancy of our cDNA library. Furthermore, approximately 40% of those randomly analyzed clones contained full-length encoding regions. To our knowledge, this is the first description of the PCR-based cDNA library from a 4-week-old chorion-free human embryo, and the presence of novel sequences within this library makes it a valuable and unique resource for studying gene expression and regulatory mechanisms that underlie the early process of human embryogenesis.
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MESH Headings
- Cloning, Molecular
- DNA, Complementary/chemistry
- DNA, Complementary/genetics
- Databases, Nucleic Acid
- Electrophoresis, Agar Gel
- Embryo, Mammalian/metabolism
- Expressed Sequence Tags
- Gene Expression Regulation, Developmental
- Gene Library
- Humans
- RNA, Messenger/genetics
- RNA, Messenger/isolation & purification
- Reverse Transcriptase Polymerase Chain Reaction
- Sequence Analysis, DNA
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Zeng XC, Peng F, Luo F, Zhu SY, Liu H, Li WX. Molecular cloning and characterization of four scorpion K(+)-toxin-like peptides: a new subfamily of venom peptides (alpha-KTx14) and genomic analysis of a member. Biochimie 2001; 83:883-9. [PMID: 11698110 DOI: 10.1016/s0300-9084(01)01326-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Four full-length cDNAs encoding the precursors of four K(+)-toxin-like peptides (named BmKK(1), BmKK(2), BmKK(3) and BmmKK(4), respectively) were first isolated from a venom gland cDNA library of the Chinese scorpion Buthus martensii Karsch. The deduced precursors of BmKK(1), BmKK(2) and BmKK(3) are all made of 54 amino acid residues including a signal peptide of 23 residues, and a mature toxin of 31 residues with three disulfide bridges. The precursor of BmKK(4) is composed of 55 amino acid residues including a signal peptide of 23 residues, a mature toxin of 30 residues cross-linked by three disulfide bridges, and an extra Gly-Lys tail which should be removed in the processing step. The four peptides displayed 24-97% sequence identity with each other, and less than 27% homology with any other scorpion toxins described. However, they shared a common disulfide bridge pattern, which was consistent with that of most short-chain K(+)-toxins, suggesting they represent a new class of scorpion toxins and their target receptors may be a subfamily of K(+) channels. We classified the BmKK toxin subfamily as alpha-KTx14 according to the classification rules. The genomic sequence of BmKK(2) was also cloned and sequenced. It consisted of two exons, disrupted by an intron of 79 bp inserted in the region encoding the C-terminal part of the signal peptide. This structure was very similar to that of other K(+)-toxins described previously.
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74
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Zhu SY, Li WX, Zeng XC. Precursor nucleotide sequence and genomic organization of BmTXKS1, a new scorpion toxin-like peptide from Buthus martensii Karsch. Toxicon 2001; 39:1291-6. [PMID: 11384716 DOI: 10.1016/s0041-0101(01)00078-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Scorpion venom contains a variety of small peptides, which can modulate Na+, K+, Ca2+ and Cl- channel conductance in excitable and non-excitable tissues. A novel full-length cDNA encoding a new toxin-like peptide (named BmTXKS1) was isolated from the venom gland cDNA library of Buthus martensii Karsch. The precursor consists of 60 amino acid residues, with a putative signal peptide of 28 residues and an extra residue, and a mature peptide of 31 residues with an amidated C-terminal. BmTXKS1 shared close homology with BmP01 in 5'UTR and the region encoding the putative signal peptide; especially, the positions of six cysteines are highly conserved among BmTXKS1, PbTX1 and P01-type subfamily of scorpion K+ channel toxins, suggesting that they all should present a common three-dimensional fold, namely the Cysteine-Stabilized alphabeta(CSalphabeta) motif. By PCR amplification of the genomic region encoding BmTXKS1, we have confirmed the identity of our cloned cDNA, and found that BmTXKS1 gene contains an intron, which is completely identical with that of the characterized scorpion K+-channel-ligands in the size, consensus junctions, putative branch point and A+T abundance.
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House SD, Mao X, Wu G, Espinelli D, Li WX, Chang SL. Chronic morphine potentiates the inflammatory response by disrupting interleukin-1beta modulation of the hypothalamic-pituitary-adrenal axis. J Neuroimmunol 2001; 118:277-85. [PMID: 11498262 DOI: 10.1016/s0165-5728(01)00337-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Interleukin-1-beta (IL-1beta) can promote inflammation by up-regulating vascular adhesion molecules and inhibit inflammation by activating the hypothalamic-pituitary-adrenal (HPA) axis to produce anti-inflammatory glucocorticoids. In this study, chronic morphine was shown to suppress IL-1beta-induction of corticotropin releasing factor (CRF) mRNA and plasma corticosterone levels. Leukocyte-endothelial adhesion (LEA) in rat mesenteric venules increased during IL-1beta- and FMLP-induced inflammation. Chronic morphine potentiated the LEA response to either IL-1beta or FMLP alone, and greatly enhanced LEA in response to combined IL-1beta and FMLP. Thus, it appears that chronic morphine exposure may promote a potentially damaging inflammatory reaction by disrupting the balance between IL-1beta-mediated local inflammation and the anti-inflammatory effects of the HPA axis.
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