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Biomedical subjects

Wei Shi

Publications and source records attributed to Wei Shi.

At least 37 records · Page 2Linked to original sources
PubMed2006

IL-12p40 is not required for islet allograft rejection.

AIM: To investigate whether IL-12p40 plays a crucial role in regulating islet allograft rejection in a streptozotocin (STZ)-induced diabetes mouse model. METHODS: C57BL/6 and IL-12p40 gene knockout mice were selected as recipient mice, to which the diabetes was induced with a treatment of STZ (150-200 mg/kg) by a single ip injection. BALB/c mice were selected as donor mice and islet cells were isolated from the mice. The 500 islets were transplanted into recipient mice beneath the capsule of the left kidney. Following the islet transplantation the glucose from the mice sera was monitored and the rejection rate of islets was analyzed. RESULTS: STZ could induce diabetes in the recipient mice within 1 week. After transplantation of allograft islets, the increased glucose in wild-type (WT) mice returned to normal level and was maintained for 10 d. Unexpectedly, the rejection rate of islet allograft between IL-12p40-deficient mice and WT mice was similar. CONCLUSION: The results suggested that, although islet allograft rejection is believed to be Th1-cell predominant, the Th1 response inducer, IL-12 and IL-23 are not essential to induce islet allograft rejection.

Animals↗
PubMed2006

Protective immunity elicited by a divalent DNA vaccine encoding both the L7/L12 and Omp16 genes of Brucella abortus in BALB/c mice.

This study was designed to evaluate the immunogenicity and the protective efficacy of a divalent fusion DNA vaccine encoding both the Brucella abortus L7/L12 protein (ribosomal protein) and Omp16 protein (outer membrane lipoprotein), designated pcDNA3.1-L7/L12-Omp16. Intramuscular injection of this divalent DNA vaccine into BALB/c mice elicited markedly both humoral and cellular immune responses. The specific antibodies exhibited a dominance of immunoglobulin G2a (IgG2a) over IgG1. In addition, the dual-gene DNA vaccine elicited a strong T-cell proliferative response and induced a large amount of gamma interferon-producing T cells upon restimulation in vitro with recombinant fusion protein L7/L12-Omp16, suggesting the induction of a typical T-helper-1-dominated immune response in vivo. This divalent DNA vaccine could also induce a significant level of protection against challenge with the virulent strain B. abortus 544 in BALB/c mice. Furthermore, the protection level induced by the divalent DNA vaccine was significantly higher than that induced by the univalent DNA vaccines pcDNA3.1-L7/L12 or pcDNA3.1-Omp16. Taken together, the results of this study verify for the first time that the Omp16 gene can be a candidate target for a DNA vaccine against brucellosis. Additionally, a divalent genetic vaccine based on the L7/L12 and Omp16 genes can elicit a stronger cellular immune response and better immunoprotection than the relevant univalent vaccines can.

Animals↗
PubMed2006

Lung development and susceptibility to chronic obstructive pulmonary disease.

Chronic obstructive pulmonary disease with emphysema has been considered to be an accelerated involutional disease of aging smokers. However, because only a proportion ( approximately 15%) of smokers develop chronic obstructive pulmonary disease with emphysema, clearly genetic susceptibility must play a significant part in determining both the age of onset and the rapidity of decline in lung function. In mice, interference with key genes, either by null mutation, hypomorphism, or gain or loss of function, results in phenotypes comprising either neonatal lethal respiratory distress if the structural effect is severe, or reduced alveolarization and/or early-onset emphysema if the effect is milder. Likewise, null mutants that interfere with matrix assembly and/or integrity, such as elastin, lysyl oxidase, or fibrillin, also result in alveolar dysplasia. Importantly, null mutation of Smad3, which encodes a receptor-activated Smad in the transforming growth factor-beta signaling pathway, results in a more subtle failure to correctly organize the alveolar matrix, which is in turn antecedent to early-onset emphysema mediated by matrix metalloproteinase-9. Furthermore, exposure to side-stream smoke profoundly exacerbates and accelerates alveolar destruction, leading to more severe early-onset emphysema in young Smad3-null mice (unpublished data). Interestingly, polymorphisms in the fibrillin, transforming growth factor-beta type II receptor, and matrix metalloproteinase-9 genes have been described in humans with emphysema. Thus, dysplastic or degraded matrix cannot provide the structural niche for alveolar stem/progenitor cells to assume the correct phenotype and/or repair the alveolar cell lineage niche. The hope is that providing the correct exogenous signals can coax them into doing so.

Age Factors↗
PubMed2006

[A distinct whole nucleus stain pattern of gamma H2AX induced by N-methyl-No-nitro-N-nitrosoguanidine].

OBJECTIVE: To characterize the DNA damage property represented by the distinct whole nucleus stain pattern of gammaH2AX induced by N-methyl-No-nitro-N-nitrosoguanidine (MNNG). METHODS: MNNG-induced gammaH2AX foci formation in human amnion FL cells was observed by immunofluorescent microscopy. DNA double-stranded breaks (DSBs) were detected by neutral comet assay. General DNA damages were detected by alkaline comet assay. RESULT: A distinct whole nucleus stain pattern of gammaH2AX was induced by high concentration MNNG (10 mg/L). 1 mg/L MNNG also induced this type of stain pattern in a small fraction of cells, although the effect was transient. Neutral comet assay did not detect any significant DSBs formation in this type of cells, while alkaline comet assay revealed the presence of DNA damage. CONCLUSION: Although normal gammaH2AX foci were regarded as a biomarker for DSBs, the whole nucleus stain pattern might represent DNA damage other than DSBs.

Amnion↗
PubMed2006

[Kinetic turbidimetric limulus assay of bacterial endotoxin in the replacement solution of on-line hemodiafiltration].

OBJECTIVE: To determine bacterial endotoxin in the replacement solution of on-line hemodiafiltration (on-line HDF) using kinetic turbidimetric limulus test. METHODS AND RESULTS: Validation test was performed with the replacement solution of on-line HDF in which quantified standard endotoxin was added. The recovery rates of endotoxin from the replacement solution and its dilutions at 1/5, 1/10, and 1/20 were 58.17%, 106.7%, 99.00% and 98.79%, respectively, suggesting that the optimal dilution was at 1/10. Standard endotoxin was added into the replacement solution of on-line HDF of 3 batches (040408, 040511,040527), and the recovery rates in their dilution at 1/10 were 76.32%, 99.00% and 96.24%, respectively. The standard endotoxin in the working curve was 1.00, 0.125, and 0.0156 Eu/ml (endotoxin unit/ml), and the dilution at 1/10 of the replacement solution is effective to eliminate the interference in limulus test. CONCLUSION: Kinetic turbidimetric limulus test provide a means to detect endotoxin in the replacement solution of on-line HDF.

Endotoxins↗
PubMed2006

Expression of c-fos in rat brain as a prelude marker of central nervous system injury in response to methylmercury-stimulation.

OBJECTIVE: To probe into the prelude marker of central nervous system injury in response to methyl mercury chloride (MMC) stimulation and the signal transduction molecular mechanism of injury in rat brain induced by MMC. METHODS: The expression of c-fos mRNA in brain and the expression of c-FOS protein in cortex, hippocampus and ependyma were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The control group was injected with physiological saline of 0.9%, while the concentrations for the exposure groups were 0.05 and 0.5, 5 mg/kg MMC respectively, and the sampling times points were 20, 60, 240, 1440 min. RESULTS: The expression of c-FOS protein in cortex and hippocampus increased significantly, the accumulation of mercury in the brain induced by 0.05 mg/Kg MMC for 20 min had no significant difference compared with the control group. The mean value was 0.0044 mg/Kg, while the protein c-FOS expression had significant difference compared with the control group (P < 0.01). More sensitive expression occurred in hippocampus and cortex, but not in ependyma. Conclusion The expression of c-FOS protein in cortex and hippocampus can predict the neurotoxicity of MMC in the early time, and immediately early gene (IEG) c-fos participates in the process of brain injury induced by MMC.

Animals↗
PubMed2006

[Determination of ergosterol amount in house dust of different indoor environment in Shanghai City by HPLC].

OBJECTIVE: A high performance liquid chromatographic (HPLC) method was developed for the determination of the amount of ergosterol in house dust, and was examined the feasibility on determination of ergosterol in house dust. According to the established method, different house dusts derived from different functional indoor air was sampled and determined. We expected to regard ergosterol as an indicator of fungal biomass. METHODS: We picked up dust samples from nine typical functional indoor area to represent different room temperature, ventilation, air conditioning, human activities, pet-feeding, et al, during Dec 2004 to Jan 2005. The house dust was sampled with a dust collector, and filtrated with a filter. Fine house dusts were extracted by ultrasonic blending, filtration, refluxing, saponification and evaporation. High liquid chromatography was carried out and combined with gas chromatography (GC)-mass spectrometry (MS) to analyze the molecular structure. RESULTS: A linearity association was observed in the range of 0.02 to 0.8 g/L ergosterol. The detection concentration was 0.0005 g/L. The intra-and inter-day relative standard deviations (RSD) were in the range of 10.2% - 11.7% and 4.54% - 7.34%, respectively. The absolute recoveries ranged between 77.1% and 80.1%. Survey results showed the amount of ergosterol differed greatly from the different sampling spots. The amount of ergosterol had a positive correlation with room temperature and people denseness, while had a negative correlation with natural ventilation, briefly. The highest amount was 66.08 microg/g (house dust). CONCLUSION: The method is sensitive, accurate and feasible. It can examine different ergosterol content in environmental matrix. Followed by GC-MS, the reliability of the results can be further checked. The sampling data show there are different degrees of fungal contamination in typical indoor air of Shanghai City.

Air Pollutants↗
PubMed2006

Expression of c-fos and oxidative stress on brain of rats reared on food from mercury-selenium coexisting mining area.

Wanshan mercury mine is the largest mercury deposit in Guizhou Province of China, but there were few reports on mercury toxic effect in the mining area. In order to study the neurotoxicity of food from Wanshan mercury mine area and probe into the effect of food from Wanshan mercury miner area on the changes of brain oxidative damage and expression of c-fos gene. The rats were exposed to mercury contaminated food for 20 d. The content of malondialdehyde (MDA), superoxide dismutase (SOD), GSH-peroxidase (GSH-px) and Glutathione (GSH) in rat brain was measured, and the effect of mercury contaminated rice on the expression of c-fos mRNA in rat brain and the expression of c-FOS protein in cortex, hippocampus were observed using reverse transcription polymerase chain reaction (RT-PCR) and immunocytochemical methods. The results showed the levels of GSH, MDA, SOD and of GSH-dependent enzymes in the rat brain changed between exposure groups and control group; The mercury polluted rice induced significantly the expression of c-fos mRNA; the c-FOS positive cells in hippocampus and cortex of exposure groups were significant different from control group (P<0.01). It could be concluded that oxidative stress signals could contribute to the induction of immediate early genes (IEGs); free radicals and their by-products might not only cause oxidative damage, but also influenced gene expression; IEGs c-fos participated in the toxicity process of brain injury by mercury polluted food.

Animals↗
PubMed2006

[Study on the reliability and validity of the 66-item version on the gross motor function measure in 0-3 year olds with cerebral palsy].

OBJECTIVE: To examine the reliability and validity of the 66-item version on the gross motor function measure (GMFM-66) to assess the gross motor functions of children below 3 years oldwith cerebral palsy. METHODS: 298 valid samples were obtained from 171 children with cerebral palsy (male 126, female 45 with mean age 19 months, age range 3-36 months) measured with GMFM-88. Then a 73-item version of GMFM (GMFM-73) special for these children was obtained by Rasch analysis. Both GMFM-66 and GMFM-73 scores of to each sample were obtained. The reliability and validity of GMFM-66 were evaluated through analyzing the correlation between the scores and between the changed scores of these two GMFM versions. The relative precision of GMFM-73 versus GMFM-66 was also analyzed. RESULTS: Significant correlations were found between the scores and between the changed scores of these two versions of GMFM. A 14% less gain in relative precision was achieved when using GMFM-73 versus GMFM-66. CONCLUSION: Results indicated that the GMFM-66 had good reliability and validity in assessing the gross motor functions of children below 3 years old with cerebral palsy.

Cerebral Palsy↗
PubMed2006

[Hepatitis C virus infection combined with systemic lupus erythematosus].

OBJECTIVE: To examine the hepatitis C virus (HCV) infection in systemic lupus erythematosus (SLE) patients, to investigate the influence of HCV infection, and to analyze the clinical appearances and experimental immunological characters of SLE. METHODS: Serum of 92 SLE patients and 58 normal control people was taken, and the HCV infection and experimental immunological characters were detected. SLE patients were divided into HCV infection group and non-HCV infection group according to the detective results. The immunological characters and clinical appearances were analyzed in the two groups. RESULTS: Thirteen of the 92 SLE patients were HCV positive, while only 2 of the 58 normal controls were positive. There were no significant differences in the clinical features including oral ulcer, arthritis, serositis, nephropathy, neural disorder, fever, as well as in the laboratory results including ANA, Anti-Ro/SSA, Anti-La/SSB, Anti-Sm, IgG and IgM in the two groups. HCV positive patients showed a lower frequency of butterfly erythema and positivity for Anti-dsDNA, and a higher frequency of cutaneous vasculitis, liver damage, positivity for RF and low C3, C4 levels. CONCLUSION: Patients with SLE showed a high prevalence of HCV infection, and HCV may cause some clinical and immunological changes in SLE.

Adolescent↗
PubMed2005

VEGF-A signaling through Flk-1 is a critical facilitator of early embryonic lung epithelial to endothelial crosstalk and branching morphogenesis.

Vascular endothelial growth factor-A (VEGF-A) signaling directs both vasculogenesis and angiogenesis. However, the role of VEGF-A ligand signaling in the regulation of epithelial-mesenchymal interactions during early mouse lung morphogenesis remains incompletely characterized. Fetal liver kinase-1 (Flk-1) is a VEGF cognate receptor (VEGF-R2) expressed in the embryonic lung mesenchyme. VEGF-A, expressed in the epithelium, is a high affinity ligand for Flk-1. We have used both gain and loss of function approaches to investigate the role of this VEGF-A signaling pathway during lung morphogenesis. Herein, we demonstrate that exogenous VEGF 164, one of the 3 isoforms generated by alternative splicing of the Vegf-A gene, stimulates mouse embryonic lung branching morphogenesis in culture and increases the index of proliferation in both epithelium and mesenchyme. In addition, it induces differential gene and protein expression among several key lung morphogenetic genes, including up-regulation of BMP-4 and Sp-c expression as well as an increase in Flk-1-positive mesenchymal cells. Conversely, embryonic lung culture with an antisense oligodeoxynucleotide (ODN) to the Flk-1 receptor led to reduced epithelial branching, decreased epithelial and mesenchymal proliferation index as well as downregulating BMP-4 expression. These results demonstrate that the VEGF pathway is involved in driving epithelial to endothelial crosstalk in embryonic mouse lung morphogenesis.

Animals↗
PubMed2005

A promising Mg(II)-ion-selective luminescent probe: structures and properties of Dy-Mn polymers with high symmetry.

Two Dy-Mn polymers, {[Dy(L1)3Mn(1.5)(H2O)3]3.125H2O}n (1, L1 = pyridine-2,6-dicarboxylic acid) and {[Dy(L2)3Mn(1.5)(H2O)6]8.25H2O}n (2, L2 = 4-hydroxylpyridine-2,6-dicarboxylic acid), with high symmetry (S6) have been prepared. Polymer 1 has a nanoporous 3D framework with channel of about 17.6 A diameter, while 2 has a honeycomb-type 2D structure with the cavity of approximately 14.4 A diameter. In the construction of multidimensional porous polymers with 3d-4f mixed metals, it is the first observation that a ligand substituent effect leads to dramatic differences in the structures formed. Luminescent studies reveal that the emission intensities of 1 and 2 increase significantly upon the addition of Mg2+, whereas the introduction of other metal ions leaves the intensity unchanged or even weakens it; hence, both of them may serve as good candidates of Mg2+ luminescent probes. To our knowledge, complex 1 is also the first example of a 3d-4f metal-based nanoporous polymer to exhibit luminescent selectivity for Mg2+. Magnetic susceptibility measurements reveal a rather rare ferromagnetic interaction in 2. Thermal gravimetric analyses and powder X-ray diffraction investigations have also been performed, suggestive of high thermal stability of 1.

Journal Article↗
PubMed2005

Synthesis, crystal structure, magnetic properties and theoretical studies on a one-dimensional polynuclear copper(II) complex [Cu2(mu1,3-SCN)2(mu'1,3-SCN)2(MPyO)2]n.

A new one-dimensional polynuclear copper(II) complex [Cu(2)(mu(1,3)-SCN)(2)(mu'(1,3)-SCN)(2)(MPyO)(2)](n)(where MPyO = 4-methylpyridine N-oxide) has been synthesized and its crystal structure determined by X-ray crystallography. In the complex there exist two kinds of bridging coordination modes, namely, mu(1,3)-SCN(-) equatorial-equatorial (EE) bridging ligand and micro'(1,3)-SCN(-) equatorial-axial (EA) bridging ligand. Two micro(1,3)-SCN(-) EE bridging ligands coordinate two copper(II) ions in a binuclear unit, and the S atoms from the micro'(1,3)-SCN(-) EA bridging ligands as axial coordinated atoms link the binuclear units into one-dimensional chains. The ESR spectra have been investigated, and variable temperature (4-300 K) magnetic measurements were analyzed using a binuclear Cu(ii) magnetic interaction formula and indicate the existence of strong antiferromagnetic coupling with 2J=- 216.00 cm(-1) between bridged copper(II) ions. Density functional calculations have been carried out on this binuclear unit, yielding a similar singlet-triplet splitting. The mechanism of strong antiferromangetic interaction is revealed according to the calculations.

Copper↗
PubMed2005

Synthesis, crystal structures, and properties of oxovanadium(IV)-lanthanide(III) heteronuclear complexes.

A new series of oxovanadium(IV)-lanthanide(III) heteronuclear complexes [Yb(H2O)8]2[(VO)2(TTHA)](3)21 H2O (1), {[Ho(H2O)7(VO)2(TTHA)][(VO)2(TTHA)](0.5)} 8.5 H2O (2), {[Gd(H2O)7(VO)2(TTHA)][(VO)2(TTHA)](0.5)}8.5 H2O (3), {[Eu(H2O)7][(VO)2(TTHA)](1.5)} 10.5 H2O (4), and [Pr2(H2O)6(SO4)2][(VO)2(TTHA)] (5) (H6TTHA=triethylenetetraaminehexaacetic acid) were prepared by using the bulky flexible organic acid H(6)TTHA as structure-directing agent. X-ray crystallographic studies reveal that they contain the same [(VO)2(TTHA)]2- unit as building block, but the Ln3+ ion lies in different coordination environments. Although the lanthanide ions always exhibit similar chemical behavior, the structures of the complexes are not homologous. Compound 1 is composed of a [Yb(H2O)8]3+ ion and a [(VO)2(TTHA)]2- ion. Compounds 2 and 3 are isomorphous; both contain a trinuclear [Ln(H2O)7(VO)2(TTHA)]+ (Ln=Ho for 2 and Gd for 3) ion and a [(VO)2(TTHA)]2- ion. Compound 4 is an extended one-dimensional chain, in which each Eu3+ ion links two [(VO)2(TTHA)]2- ions. For 5, the structure is further assembled into a three-dimensional network with an interesting framework topology comprising V2Pr2 and V4Pr2 heterometallic lattices. Moreover, 4 and 5 are the first oxovanadium(IV)-lanthanide(III) coordination polymers and thus enlarge the realm of 3d-4f complexes. The IR, UV/Vis, and EPR spectra and the magnetic properties of the heterometallic complexes were studied. Notably, 2 shows unusual ferromagnetic interactions between the VO2+ and Ho3+ ions.

Journal Article↗
PubMed2005

Mathematical analysis of affinity membrane chromatography.

A mathematical model including convection, diffusion and Freundlich adsorption is developed. To examine the validity of the model, the affinity membranes were prepared by coating chitosan on the nylon membranes, a ligand of poly-L-lysine was bound to the chitoan-coating membranes, and the adsorption behavior of bilirubin through the stacked affinity membranes was investigated. The agreements between the theoretical and experimental results are exceptional. Using our new model, we show that: (1) As Pe increases, the breakthrough curves become sharper. For Pe greater than 30, the effect of axial diffusion is insignificant; (2) As m increases, the time of total saturation is delayed and the loading capacity at the point of breakthrough is increased; (3) As n decreases, the time of total saturation is delayed and the loading capacity at the point of breakthrough is increased; (4) As r increases, both the time of total saturation and the loading capacity at the point of breakthrough are increased; (5) adsorption rate influences the time of total saturation strongly but contributes little to the loading capacity.

Adsorption↗
PubMed2005

Generation of backward terahertz waves in GaSe crystals.

We have observed a backward-propagating terahertz wave by mixing two coherent infrared beams in two GaSe crystals. For the 47 mm long crystal, the output wavelength can be tuned in the wide range of 167.6 to 2060 microm (0.146 to 1.79 THz), whereas the output peak power reaches 217 W. The corresponding power conversion efficiency is approximately 0.03%.

Journal Article↗