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Biomedical subjects

Jing Wang

Publications and source records attributed to Jing Wang.

At least 109 records · Page 6Linked to original sources
PubMed2006

Identification and chemistry of C4H3 and C4H5 isomers in fuel-rich flames.

Quantitative identification of isomers of hydrocarbon radicals in flames is critical to understanding soot formation. Isomers of C4H3 and C4H5 in flames fueled by allene, propyne, cyclopentene, or benzene are identified by comparison of the observed photoionization efficiencies with theoretical simulations based on calculated ionization energies and Franck-Condon factors. The experiments combine molecular-beam mass spectrometry (MBMS) with photoionization by tunable vacuum-ultraviolet synchrotron radiation. The theoretical simulations employ the rovibrational properties obtained with B3LYP/6-311++G(d,p) density functional theory and electronic energies obtained from QCISD(T) ab initio calculations extrapolated to the complete basis set limit. For C4H3, the comparisons reveal the presence of the resonantly stabilized CH2CCCH isomer (i-C4H3). For C4H5, contributions from the CH2CHCCH2 (i-C4H5) and some combination of the CH3CCCH2 and CH3CHCCH isomers are evident. Quantitative concentration estimates for these species are made for allene, cyclopentene, and benzene flames. Because of low Franck-Condon factors, sensitivity to n-isomers of both C4H3 and C4H5 is limited. Adiabatic ionization energies, as obtained from fits of the theoretical predictions to the experimental photoionization efficiency curves, are within the error bars of the QCISD(T) calculations. For i-C4H3 and i-C4H5, these fitted adiabatic ionization energies are (8.06 +/- 0.05) eV and (7.60 +/- 0.05) eV, respectively. The good agreement between the fitted and theoretical ionization thresholds suggests that the corresponding theoretically predicted radical heats of formation (119.1, 76.3, 78.7, and 79.1 kcal/mol at 0 K for i-C4H3, i-C4H5, CH3CCCH2, and CH3CHCCH, respectively) are also quite accurate.

Carbon Compounds, Inorganic↗
PubMed2006

Dopamine transporter is essential for the maintenance of spontaneous activity of auditory nerve neurones and their responsiveness to sound stimulation.

Dopamine, a neurotransmitter released by the lateral olivocochlear efferents, has been shown tonically to inhibit the spontaneous and sound-evoked activity of auditory nerve fibres. This permanent inhibition probably requires the presence of an efficient transporter to remove dopamine from the synaptic cleft. Here, we report that the dopamine transporter is located in the lateral efferent fibres both below the inner hair cells and in the inner spiral bundle. Perilymphatic perfusion of the dopamine transporter inhibitors nomifensine and N-[1-(2-benzo[b]thiophenyl)cyclohexyl]piperidine into the cochlea reduced the spontaneous neural noise and the sound-evoked compound action potential of the auditory nerve in a dose-dependent manner, leading to both neural responses being completely abolished. We observed no significant change in cochlear responses generated by sensory hair cells (cochlear microphonic, summating potential, distortion products otoacoustic emissions) or in the endocochlear potential reflecting the functional state of the stria vascularis. This is consistent with a selective action of dopamine transporter inhibitors on auditory nerve activity. Capillary electrophoresis with laser-induced fluorescence (EC-LIF) measurements showed that nomifensine-induced inhibition of auditory nerve responses was due to increased extracellular dopamine levels in the cochlea. Altogether, these results show that the dopamine transporter is essential for maintaining the spontaneous activity of auditory nerve neurones and their responsiveness to sound stimulation.

Acoustic Stimulation↗
PubMed2006

Mini-alphaB-crystallin: a functional element of alphaB-crystallin with chaperone-like activity.

Alpha-crystallin is a member of the family of small heat-shock proteins (sHSP) and is composed of two subunits, alphaA-crystallin and alphaB-crystallin, which exhibit molecular chaperone-like properties. In a previous study, we found that residues 70-88 in alphaA-crystallin can function like a molecular chaperone by preventing the aggregation and precipitation of denaturing substrate proteins [Sharma, K. K., et al. (2000) J. Biol. Chem. 275, 3767-3771]. In this study, we show that the complementary sequence in alphaB-crystallin, residues 73-92 (DRFSVNLDVKHFSPEELKVK), is the functional chaperone site of alphaB-crystallin. Like the mini-alphaA-crystallin chaperone, the mini-alphaB-crystallin chaperone interacts with 1,1'-bi(4-anilino) naphthalene-5,5'-disulphonic acid (bis-ANS) and also possesses significant beta-sheet and random coil structure. Deletion of four residues (DRFS) from the N-terminus or deletion of C-terminus LKVK residues from the 73-92 peptide abolishes the chaperone-like activity against denaturing alcohol dehydrogenase. However, removal of DRFS or HFSPEELKVK is necessary to completely abolish the antiaggregation property of the peptide in insulin reduction assay. Substitution of Asp at a site corresponding to D80 in alphaB-crystallin with d-Asp or beta-Asp results in a significant loss of chaperone-like activity. Kynurenine modification of His in the peptide abolishes the antiaggregation property of the mini-chaperone. These data suggest that the 73-92 region in alphaB-crystallin is one of the substrate binding sites during chaperone activity.

Amino Acid Sequence↗
PubMed2006

Microenvironmental and conformational structure of triblock copolymers in aqueous solution by 1H and 13C NMR spectroscopy.

1H and 13C nuclear magnetic resonance (NMR) spectra of poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) triblock copolymers in D2O solutions have been systematically investigated. The detailed assignments of various 1H and 13C NMR signals are presented. The hyperfine structure of PO -CH2- protons was clearly assigned, the arising reason of this hyperfine structure was attributed to the influence of the chiral center of -CHCH3- groups and the direct coupling between the PO -CH2- and -CH3 protons. The external standard 2,2-dimethyl-2-silapentane-5-sulfonate sodium salt (DSS) was firstly applied in this system. Accurate chemical shift values referenced to the external standard DSS were obtained. 1H NMR chemical shift of PO -CH2- and -CH3 signals shows a larger decrease in ppm values than that of EO -CH2- signal with the increase of PPO/PEO ratio or temperature indicating that PO segments exist in a more hydrophobic microenvironment. A new resonance signal assigned to the PO -CH2- protons appeared when the temperature is above the CMT, which is attributed to the breakdown of the intra-molecular (C-H)...O hydrogen bond between the PO -CH2- protons and the ester oxygens. The breakdown of this intra-molecular hydrogen bond may result in a decrease of gauche conformers of the PPO chain. The increase of 13C NMR chemical shift of block copolymers validates this conformational change assumption. It can be inferred that the amount of gauche conformers decreases whereas that of trans conformers increases in both PO and EO chains when elevating the PPO/PEO ratio or temperature. The observed 13C NMR chemical shifts of PO segments show a bigger increase than those of EO segments, supporting the formation of a nonpolar microenvironment around PO segments.

Journal Article↗
PubMed2006

Antibody-induced transplantation tolerance that is dependent on thymus-derived regulatory T cells.

Targeting of the CD45RB isoform by mAb (anti-CD45RB) effectively induces donor-specific tolerance to allografts. The immunological mechanisms underlying the tolerant state remain unclear although some studies have suggested the involvement of regulatory T cells (T-regs). Although their generative pathway remains undefined, tolerance promoting T-regs induced by systemic anti-CD45RB treatment have been assumed to originate in the peripheral immune system. We demonstrate herein that separable effects on the peripheral and central immune compartments mediate graft survival induced by anti-CD45RB administration. In the absence of the thymus, anti-CD45RB therapy is not tolerogenic though it retains peripheral immunosuppressive activity. The thymus is required for anti-CD45RB to produce indefinite graft survival and donor-specific tolerance, and this effect is accomplished through thymic production of donor-specific T-regs. These data reveal for the first time an Ab-based tolerance regimen that relies on the central tolerance pathway.

Adoptive Transfer↗
PubMed2006

The ribosomal protein L32-2 (RPL32-2) of S. pombe exhibits a novel extraribosomal function by acting as a potential transcriptional regulator.

Ribosomal proteins play important roles in stabilizing the rRNA structure to facilitate protein synthesis in ribosome. In the present study, we analyzed the potential extraribosomal function of the ribosomal protein L32-2 (RPL32-2), which was expressed by a gene clone isolated from a cDNA library of Schizosaccharomyces pombe (S. pombe). RPL32-2 fused with the GAL4 DNA-bind domain or the GAL4 transcriptional activating domain could, respectively, activate transcriptions of reporter genes in yeast strain AH109. The RPL32-2 mutants with truncation of either the N- or the C-terminal domain resulted in abolishment of this regulatory effect. The DNA binding site for RPL32-2 of S. pombe was identified by using a random oligonucleotide selection strategy and gel motility shift assay and Western blotting confirmed its binding specificity. Moreover, we found RPL32-2 was also able to interact with a to-be-identified AT sequence binding protein. These data suggest that RPL32-2 of S. pombe, besides its ribosomal function, may also act as a potential transcriptional regulator in nucleus.

Binding Sites↗
PubMed2006

Chromosomal abnormalities and adverse pregnancy outcome with maternal serum second trimester triple screening test for fetal Down syndrome in 4,860 Chinese women.

OBJECTIVE: To investigate the efficiency of maternal serum triple screening for the genetic abnormality in second-trimester and the morbidity of adverse pregnancy outcome in false positive results of the test. METHODS: A total of 4,680 pregnant women with singleton pregnancies assigned in Obs & Gyn Hospital, Fudan University, underwent triple screening test (alpha fetoprotein, AFP; human chorionic gonadotropin, HCG and unconjugated estriol, uE3) by fluorescence enzyme immunoassay between 2003 and 2005. The valid MoM (Multiples of Median) value of mid-trimester serum AFP, uE3, and hCG and risk assessments was provided by Beckman Coulter Co. when applied in the prenatal Down syndrome screening service. The study compares the incidence of chromosomal abnormalities with Down syndrome in screen positive women and compares to the MoM value established in the literature. The risks of having a fetus with congenital abnormalities or of developing obstetric complications in the screen positive women with their matched controls. RESULTS: The MoM values for the triple tests of our study are similar to established values of literature. Only 51.01% women with pregnancies agree to receive screening. Amniocentesis utilization rate was 55.12% in the screen-positive pregnancies. The false positive rate was 6.89% and the median of maternal age of the women was 28.13 (range 19 to 49) years old. Chromosomal abnormalities were identified in 21 pregnancies, including 9 cases of trisomy 21. The detection rate was 77.77%. Pregnancies with positive screening results had a significantly higher risk of adverse outcomes than those with negative results (P< 0.05). Whereas there was no difference in the incidences of fetal congenital appearance or skeleton abnormality. CONCLUSION: Adjusting MoM values of local unaffected populations is limited to increasing the detection rate. Because chromosomal defects have variable exhibitions, amniocentesis utilization is still a choice for screen-positive pregnancies. Screen-positive pregnancies had increased risk of chromosomal abnormalities.

Adult↗
PubMed2006

Human prolyl-4-hydroxylase alpha(I) transcription is mediated by upstream stimulatory factors.

Prolyl-4-hydroxylase alpha(I) (P4Halpha(I)) is the rate-limiting subunit for P4H enzyme activity, which is essential for procollagen hydroxylation and secretion. In the current study, we have characterized the human P4Halpha(I) promoter for transcription factors and DNA elements regulating P4Halpha(I) expression. Using a progressive deletion cloning approach, we have constructed pGL3-P4Halpha(I) recombinant plasmids. We have identified a positive regulatory region at the positions of bp -184 to -97 responsible for approximately 80% of the P4Halpha(I) promoter efficiency. Three E-boxes were located within this region, and the E-box at position bp -135 explains most of the regulatory capacity. Upstream stimulatory factors (USF1/USF2) were shown to bind on the E-box using chromatin immunoprecipitation assay. Suppression of USF1 and/or USF2 using specific short interference RNA resulted in a significant reduction in P4Halpha(I) promoter activity, and overexpressed USF1 or USF2 increased P4Halpha(I) promoter activity significantly. Although transforming growth factor beta1 increased the USF1/USF2-E-box binding and P4Halpha(I) promoter activity, this up-regulatory effect can be largely prevented by USF1/USF2-specific short interference RNA. On the other hand, cigarette smoking extracts, which have been shown to suppress P4Halpha(I) expression, inhibited the binding between the USF1/USF2 and E-box, resulting in a reduced P4Halpha(I) promoter activity. Furthermore, the E-box on the P4Halpha(I) promoter appeared to indiscriminately bind with either USF1 or USF2, with a similar outcome on the promoter efficiency. In conclusion, our study shows that USF1/USF2 plays a critical role in basal P4Halpha(I) expression, and both positive (transforming growth factor beta1) and negative (cigarette smoking extract) regulators appear to influence the USF-E-box interaction and affect P4Halpha(I) expression.

Base Sequence↗
PubMed2006

Nuclear receptor Rev-erbalpha is a critical lithium-sensitive component of the circadian clock.

Lithium is commonly used to treat bipolar disorder, which is associated with altered circadian rhythm. Lithium is a potent inhibitor of glycogen synthase kinase 3 (GSK3), which regulates circadian rhythm in several organisms. In experiments with cultured cells, we show here that GSK3beta phosphorylates and stabilizes the orphan nuclear receptor Rev-erbalpha, a negative component of the circadian clock. Lithium treatment of cells leads to rapid proteasomal degradation of Rev-erbalpha and activation of clock gene Bmal1. A form of Rev-erbalpha that is insensitive to lithium interferes with the expression of circadian genes. Control of Rev-erbalpha protein stability is thus a critical component of the peripheral clock and a biological target of lithium therapy.

ARNTL Transcription Factors↗
PubMed2006

The novel tumor suppressor p33ING2 enhances nucleotide excision repair via inducement of histone H4 acetylation and chromatin relaxation.

p33ING2 is a novel candidate tumor suppressor, which has been shown to be involved in the regulation of gene transcription, cell cycle arrest, and apoptosis in a p53-dependent manner for maintaining the genomic stability. Previously, we showed that p33ING2 promoted UV-induced apoptosis in human melanoma cells. To further reveal the role of p33ING2 in cellular stress response to UV irradiation, we hypothesized that p33ING2 may enhance the repair of UV-damaged DNA, similarly to its homologue p33(ING1b). Using the host-cell reactivation assay, we show that overexpression of p33ING2 significantly enhances nucleotide excision repair of UV-induced DNA damage in melanoma cells in a p53-dependent manner. Furthermore, DNA repair is completely abolished in cells treated with p33ING2 small interfering RNA, suggesting that a physiologic level of p33ING2 is required for nucleotide excision repair. In addition, we found that p33ING2 is an essential factor for UV-induced rapid histone H4 acetylation, chromatin relaxation, and the recruitment of damage recognition protein, xeroderma pigmentosum group A protein, to the photolesions. These observations suggest that p33ING2 is required for the initial DNA damage sensing and chromatin remodeling in the nucleotide excision repair process.

Acetylation↗
PubMed2006

Protein kinase A(PKA)-restrictive and PKA-permissive phases of oocyte maturation.

Substantial evidence has indicated that cAMP-dependent protein kinase (protein kinase A or PKA) plays a critical role in maintaining meiotic prophase arrest in vertebrate oocytes. However, PKA activity dynamic and its physiological substrate profile during oocyte maturation remain poorly defined. We have recently developed a novel PKA substrate construct which we employ to monitor PKA activity in live oocytes. We demonstrated here that, during progesterone-induced oocyte maturation, PKA was inactivated within 30 min of the addition of progesterone and thereafter remained inactivated throughout the entire maturation process. However, artificial reactivation of endogenous PKA had differential consequences, depending on the timing of PKA reactivation. Reactivation of endogenous PKA at any time prior to germinal vesicle breakdown (GVBD) inhibited progesterone-induced GVBD. PKA reactivation at GVBD, or thereafter, did not interfere with meiosis I to meiosis II transition, nor did it interfere with metaphase II arrest. These results demonstrate for the first time a PKA-restrictive and a PKA-permissive phase in oocyte maturation.

Animals↗
PubMed2006

Pre-activation of T lymphocytes by low dose of concanavalin A aggravates toll-like receptor-3 ligand-induced NK cell-mediated liver injury.

Concanavalin A (Con A), a widely used murine T cell stimulator, could induce T cell-mediated hepatitis when used in an abundant dosage. However, the immune-modulating role of non-hepatotoxic dosage of Con A in hepatic immune responses remains obscure. In order to evaluate the effect of non-hepatotoxic Con A on hepatic NK cells, pretreatment of mice with low dose of Con A was performed on polyinosinic-polycytidylic acid (poly I:C) [toll-like receptor-3 (TLR-3) ligand]-induced NK cell-mediated hepatitis. The role of the Con A-pre-activated T cells in NK cell function was then determined. The results demonstrated that Con A pretreatment aggravated poly I:C-induced liver injury with elevation of serum transaminases, hepatic necrosis and serum IFN-gamma level. In parallel to the enhanced accumulation of activated NK cells into liver, the natural cytotoxicity and IFN-gamma production by hepatic NK cells were significantly augmented. Moreover, depletion of T cells suppressed the aggravating effect of Con A pretreatment. Collectively, the aggravation of poly I:C-induced hepatitis by Con A pretreatment may be due to the generation of more vigorous NK cells which is dependent on the presence of T cells. This investigation will help to explain the synergistic effects of NK and T cells in liver inflammatory injury.

Animals↗
PubMed2006

Blockade of EGFR and ErbB2 by the novel dual EGFR and ErbB2 tyrosine kinase inhibitor GW572016 sensitizes human colon carcinoma GEO cells to apoptosis.

Coexpression of the epidermal growth factor receptor (EGFR) family receptors is found in a subset of colon cancers, which may cooperatively promote cancer cell growth and survival, as heterodimerization is known to provide for diversification of signal transduction. Recently, efforts have been made to develop novel 4-anilinoquinazoline and pyridopyrimidine derivatives to inhibit EGFR and ErbB2 kinases simultaneously. In this study, we tested the efficacy of a novel reversible dual inhibitor GW572016 compared with the selective EGFR and ErbB2 tyrosine kinase inhibitors (TKI) AG1478 and AG879 and their combination, using the human colon adenocarcinoma GEO mode. GEO cells depend on multiple ErbB receptors for aberrant growth. A synergistic effect on inhibition of cell proliferation associated with induction of apoptosis was observed from the combination of AG1478 and AG879. Compared with AG1478 or AG879, the single TKI compound GW572016 was a more potent inhibitor of GEO cell proliferation and was able to induce apoptosis at lower concentrations. Western blot analysis revealed that AG1478 and AG879 were unable to suppress both EGFR and ErbB2 activation as well as the downstream mitogen-activated protein kinase (MAPK) and AKT pathways as single agents. In contrast, GW572016 suppressed the activation of EGFR, ErbB2, MAPK, and AKT in a concentration-dependent manner. Finally, in vivo studies showed that GW572016 treatment efficiently blocked GEO xenograft growth at a dose range of 30 to 200 mg/kg with a twice-daily schedule. In summary, our study indicates that targeting both EGFR and ErbB2 simultaneously could enhance therapy over that of single agents directed at EGFR or ErbB2 in cancers that can be identified as being primarily heterodimer-dependent.

Animals↗
PubMed2006

Improved resolution in two-dimensional 1H NMR spectra of peptides by band-selective, homonuclear decoupling during both the evolution and acquisition periods: application to characterization of the binding of peptides by heparin.

Two-dimensional 1H NMR experiments that achieve band-selective, homonuclear decoupling in both the indirectly detected F1 and directly detected F2 dimensions were used to assign the highly overlapped 1H NMR spectrum of the peptide Ac-SRGKARVRAKVKDQTK-NH2, both free in solution and bound to heparin. Band-selective, homonuclear decoupling during the evolution period was achieved using a double pulsed field gradient spin-echo (DPFGSE) with semi-selective shaped pulses; band-selective, homonuclear decoupling during the acquisition period was achieved by time-shared semi-selective shaped pulse decoupling. Regular TOCSY, ROESY and NOESY spectra and TOCSY, ROESY and NOESY spectra measured with band-selective, homonuclear decoupling in the evolution (F1) dimension (BASHD-TOCSY, ROESY and NOESY spectra) and with band-selective, homonuclear decoupling in both the F1 and F2 dimensions (D-(or Double)-BASHD-TOCSY, ROESY and NOESY spectra) are reported and compared for the peptide and its heparin complex. Complete assignment of the 1H-NMR spectra of the free and heparin-complexed peptide was achieved with the high resolution of the D-BASHD-TOCSY, ROESY and NOESY spectra. Characterization of the heparin-complexed peptide is of interest because of the ability of the peptide to neutralize the anticoagulant activity of heparin.

Amino Acid Sequence↗
PubMed2006

Expressed proteome analysis of human hepatocellular carcinoma in nude mice (LCI-D20) with high metastasis potential.

We report for the first time an expressed proteome for human hepatocellular carcinoma (HCC) in nude mice model. Most cases of human liver cancer are HCC with highly metastatic ability. Therefore, the early prediction or diagnosis and effective treatment are the key points of research. We have previously successfully established a human HCC nude mice model (LCI-D20) with high metastasis potential. To understand better the tumor biology of HCC it is worth to explore the relativity of all expressed protein profiles in the LCI-D20 HCC nude mice model. With advanced proteomics technologies, we have carried out a proteomic analysis with following stages: protein sample preparation of cancer tissue, including total cellular extraction and sequential fractionation, 2-DE and 2-D LC separation, ESI/MALDI-MS/MS identification, as well as data-dependent bioinformatics. The identified proteins were classified bioinformatically respective to their function, biological process and intracellular localization. Some important proteins found in HCC, e.g. metabolism enzymes, proteins regulating cell motility, signaling proteins, and heat shock proteins, are discussed in terms of their metastasis.

Animals↗
PubMed2006

HUPO Brain Proteome Project: summary of the pilot phase and introduction of a comprehensive data reprocessing strategy.

The Human Proteome Organisation (HUPO) initiated several projects focusing on the proteome analysis of distinct human organs. The Brain Proteome Project (BPP) is the initiative dedicated to the brain, its development and correlated diseases. Two pilot studies have been performed aiming at the comparison of techniques, laboratories and approaches. With the help of the results gained, objective data submission, storage and reprocessing workflow have been established. The biological relevance of the data will be drawn from the inter-laboratory comparisons as well as from the re-calculation of all data sets submitted by the different groups. In the following, results of the single groups as well as the centralised reprocessing effort will be summarised and compared, showing the added value of this concerted work.

Animals↗