PubMed Health⌕ Search

Biomedical subjects

Ying Wang

Publications and source records attributed to Ying Wang.

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

Comparison of three methods for isolation of nucleic acids from membranate inner ear tissue of rats.

BACKGROUND: Mitochondrial DNA mutations have been found in sensorineural deafness. The aim of this study was to compare three methods for extraction of nucleic acid from membranate inner ear tissue of rats. METHODS: Alkaline denaturation, a conventional phenol-chloroform method and Trizol reagent were respectively used to extract the slight nucleic acid from membranate inner ear tissue of rats. We assessed the amount and quality of nucleic acid using a UV-spectrometer and polymerase chain reaction (PCR). RESULTS: The yield and purity (OD260/OD280) of DNA from inner ear tissue using the phenol-chloroform method was the highest of the three methods. Mitochondrial DNA (mtDNA) fragment can be amplified by PCR from nucleic acid prepared by all methods, while no nuclear DNA (nDNA) fragment can be amplified by method of alkaline denaturation. Both nuclear and mitochondrial genes could be amplified by reverse transcriptional PCR from the RNA prepared by Trizol reagent. CONCLUSION: Adequate amount and high-quality of mtDNA, nDNA and RNA were obtained from unilateral membranate inner ear tissue of rats. Method of alkaline denaturation could be chosen when mtDNA without nDNA was needed, while phenol-chloroform method was suitable for extracting total DNA (including nDNA and mtDNA); method with Trizol reagent was suitable for extracting total RNA and total DNA.

Animals↗
PubMed2006

ZNF325, a novel human zinc finger protein with a RBaK-like RB-binding domain, inhibits AP-1- and SRE-mediated transcriptional activity.

Mitogen-activated protein kinase (MAPK) signal transduction pathways are among the most widespread mechanisms of eukaryotic cell regulation. The zinc-finger-containing transcription factors have been previously revealed to be involved in the regulation of the MAPK signaling pathways. Here, we have identified a novel human zinc-finger transcriptional repressor, ZNF325, that contains a RBaK-like RB-binding domain and 15 tandem repeated C2H2 type zinc fingers. Northern blot analysis indicates that a 2.7 kb transcript specific for ZNF325 is widely expressed in all tissues examined at adult stage and in most of the embryonic tissues. Overexpression of ZNF325 in COS-7 cells inhibits the transcriptional activities of AP-1 and SRE. The deletion and RNAi analysis indicate that the C2H2 zinc finger motifs represent the basal transcriptional repressive activity. These results indicate that the ZNF325 protein may act as a novel transcription repressor in MAPK signaling pathway to mediate cellular functions.

Amino Acid Sequence↗
PubMed2006

Structure-activity relationship studies on a series of novel, substituted 1-benzyl-5-phenyltetrazole P2X7 antagonists.

1-Benzyl-5-aryltetrazoles were discovered to be novel antagonists for the P2X(7) receptor. Structure-activity relationship (SAR) studies were conducted around both the benzyl and phenyl moieties. In addition, the importance of the regiochemical substitution on the tetrazole was examined. Compounds were evaluated for activity to inhibit calcium flux in both human and rat recombinant P2X(7) cell lines using fluorometric imaging plate reader technology. Analogues were also assayed for their ability to inhibit IL-1beta release and to inhibit P2X(7)-mediated pore formation in human THP-1 cells. Compound 15d was advanced to efficacy studies in a model of neuropathic pain where significant reversal of mechanical allodynia was observed at doses that did not affect motor coordination.

Analgesics↗
PubMed2006

Dopachrome tautomerase (Dct) regulates neural progenitor cell proliferation.

DOPAchrome tautomerase (Dct) functions downstream of tyrosinase in the biosynthetic pathway of eumelanin by catalyzing the conversion of dopachrome to 5,5-dihydroxyindole-2-carboxylic acid (DHICA) in pigment cells. Dct transcription is regulated directly or synergistically by Pax3, Sox10 and microphthalmia transcription factor (MITF). Using Dct-lacZ transgenic mice, we measured the spatial and temporal pattern of Dct expression in vivo during neocortical neurogenesis in the brain. Dct was expressed in all layers of the dorsal telencephalon in E10.5. At E15.5 and E17.5 when cortical neurogenesis occurs, expression of Dct was primarily localized to the ventricular zone (VZ) where neuronal stem cells reside. Blocking endogenous Dct by RNAi decreased proliferation of embryonic cortical neural progenitor cells (by 48%, P < 0.05), as determined by BrdU incorporation. In adult brain, Dct/Dct expression decreased in the subventricular zone (SVZ), dentate gyrus and olfactory bulb (OB). However, strong expression of Dct was observed in rostral migratory stream (RMS) and septum. Overexpression of Dct in SVZ cells derived from the adult mice significantly increased the number of cells by 260%, whereas silencing Dct by RNAi decreased cell numbers by 25.8% at 48 h post-nucleofection (P < 0.05). The results of RT-PCR analysis revealed that Dct in the brain lacks exon 7 and is identical to the form of Dct found in neural-crest-derived melanocytes. Our data indicate that Dct, previously known as a melanoblast marker, regulates neural progenitor cell proliferation.

Animals↗
PubMed2006

Cellular uptake of exogenous human PDCD5 protein.

PDCD5 (human programmed cell death 5) plays a significant role in apoptotic and paraptotic cell deaths. However, it was found that recombinant PDCD5 added exogenously to culture medium could also enhance programmed cell death triggered by certain stimuli. Here we show that PDCD5 has a remarkable role in intercellular transport in various cells (endogenous caveolin-1-positive and -negative cells) through a clathrin-independent endocytic pathway that originates from heparan sulfate proteoglycan binding and lipid rafts. These conclusions are supported by the studies of slow internalization kinetics of PDCD5 endosomes, by the resistance of endosomes to nonionic detergents, by the overexpression of the clathrin dominant negative mutant form, which did not block PDCD5-fluorescein isothiocyanate uptake, and by PDCD5 localization in lipid rafts by immunofluorescence, electron microscopy techniques, and sucrose density centrifugation. This is further supported by the findings that certain drugs that disrupt lipid rafts, compete with cell membrane heparan sulfate proteoglycans, or block the caveolae pathway, impair the PDCD5 internalization process. The translocation activity of PDCD5 may possess physiological significance and be a potential mechanism for its programmed cell death-promoting activity. PDCD5 protein also has the ability to drive the internalization of large protein cargo, depending on the residues 109-115 mapped by deletion mutagenesis, and can introduce the Mdm-2 binding domain of human p53 into living cells to induce cell death in human cancer cells, indicating that PDCD5 may serve as a vehicle and thus have potential in the field of protein delivery to the cells. This is the first evidence of such findings.

Apoptosis Regulatory Proteins↗
PubMed2006

Mechanism of apoptosis induced by the inhibition of fatty acid synthase in breast cancer cells.

Fatty acid synthase (FAS) has been found to be overexpressed in a wide range of epithelial tumors, including breast cancer. Pharmacologic inhibitors of FAS cause apoptosis of breast cancer cells and result in decreased tumor size in vivo. However, how the inhibition of FAS induces apoptosis in tumor cells remains largely unknown. To understand the apoptotic pathway resulting from direct inhibition of FAS, we treated breast tumor cells with or without FAS small interfering RNA (siRNA) followed by a microarray analysis. Our results indicated that the proapoptotic genes BNIP3, tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), and death-associated protein kinase 2 (DAPK2) were significantly up-regulated on direct inhibition of the FAS gene. We also found that the knockdown of FAS expression significantly increased ceramide level in the tumor cells, and this increase was abrogated by acetyl-CoA carboxylase inhibitor. In addition, carnitine palmitoyltransferase-1 (CPT-1) inhibitor up-regulated the ceramide and BNIP3 levels in these cells, whereas treatment of tumor cells with FAS siRNA in the presence of a ceramide synthase inhibitor abrogated the up-regulation of BNIP3 and inhibited apoptosis. Furthermore, we found that treatment of cells with BNIP3 siRNA significantly counteracted the effect of FAS siRNA-mediated apoptosis. Consistent with these results, a significant inverse correlation was observed in the expression of FAS and BNIP3 in clinical samples of human breast cancer. Collectively, our results indicate that inhibition of FAS in breast cancer cells causes accumulation of malonyl-CoA, which leads to inhibition of CPT-1 and up-regulation of ceramide and induction of the proapoptotic genes BNIP3, TRAIL, and DAPK2, resulting in apoptosis.

Apoptosis↗
PubMed2006

Spontaneous CdTe --> alloy --> CdS transition of stabilizer-depleted CdTe nanoparticles induced by EDTA.

CdTe nanoparticles stabilized by l-cysteine are chemically transformed into CdS nanoparticles of the same diameter via an intermediate CdTeS alloy without any auxiliary source of sulfur. The reaction is induced by ethylenediaminetetraacetic acid dipotassium salt dehydrate (EDTA), which was demonstrated experimentally to act as a catalyst by partially removing thiol stabilizers from the nanoparticle surface. It is hypothesized that addition of EDTA facilitates Te(2-) release, and oxidation of Te(2-) drives the nanoparticle transition process. Unlike many reports on reactions catalyzed by nanocolloids, this is likely to be the first observation of a catalytic reaction in which nanoparticles function as a substrate rather than a catalyst. It opens new pathways for the synthesis of novel nanoscale II-VI and other semiconductors and represents an interesting case of chemical processes in nanocolloids with reactivity increased by depletion of the surface layer of thiol stabilizers. This includes but is not limited to accurate control over the particle composition and crystallization rate. The slow rate of the CdTe --> alloy --> CdS transition is important for minimizing defects in the crystal lattice and results in a substantial increase of the quantum yield of photoluminescence over the course of the transition.

Alloys↗
PubMed2006

Matrix metalloproteinase 2 (MMP2) and MMP9 secreted by erythropoietin-activated endothelial cells promote neural progenitor cell migration.

We investigated the hypothesis that endothelial cells activated by erythropoietin (EPO) promote the migration of neuroblasts. This hypothesis is based on observations in vivo that treatment of focal cerebral ischemia with EPO enhances the migration of neuroblasts to the ischemic boundary, a site containing activated endothelial cells and angiogenic microvasculature. To model the microenvironment within the ischemic boundary zone, we used a coculture system of mouse brain endothelial cells (MBECs) and neural progenitor cells derived from the subventricular zone of the adult mouse. Treatment of MBECs with recombinant human EPO (rhEPO) significantly increased secretion of matrix metalloproteinase 2 (MMP2) and MMP9. rhEPO-treated MBEC supernatant as conditioned medium significantly increased the migration of neural progenitor cells. Application of an MMP inhibitor abolished the supernatant-enhanced migration. Incubation of neurospheres alone with rhEPO failed to increase progenitor cell migration. rhEPO activated phosphatidylinositol 3-kinase/Akt (PI3K/Akt) and extracellular signal-regulated kinase (ERK1/2) in MBECs. Selective inhibition of the PI3K/Akt and ERK1/2 pathways significantly attenuated the rhEPO-induced MMP2 and MMP9, which suppressed neural progenitor cell migration promoted by the rhEPO-activated MBECs. Collectively, our data show that rhEPO-activated endothelial cells enhance neural progenitor cell migration by secreting MMP2 and MMP9 via the PI3K/Akt and ERK1/2 signaling pathways. These data demonstrate that activated endothelial cells can promote neural progenitor cell migration, and provide insight into the molecular mechanisms underlying the attraction of newly generated neurons to injured areas in brain.

Animals↗
PubMed2006

Isoflurane preconditioning protects human neuroblastoma SH-SY5Y cells against in vitro simulated ischemia-reperfusion through the activation of extracellular signal-regulated kinases pathway.

It has been reported that a prior exposure of isoflurane, a commonly used volatile anesthetic in clinical practice, reduces brain cell death after ischemia. This isoflurane preconditioning-induced neuroprotection has been shown in rat in vivo and in vitro brain ischemia models. To investigate the mechanisms of this protection, we used the human neuroblastoma SH-SY5Y cells and simulated ischemia in vitro by oxygen-glucose deprivation. We found that isoflurane exposure for 30 min at 24 h before a 5-h oxygen-glucose deprivation dose-dependently reduced cell death. Isoflurane exposure induced phosphorylation/activation of extracellular signal-regulated kinase (ERK). Inhibition of the phospho-ERK expression abolished the isoflurane preconditioning-induced protection. Isoflurane exposure also increased the expression of early growth response gene 1 (Egr-1) and Bcl-2, proteins downstream of ERK. Egr-1 is a transcription factor and plays a role in cell survival. Bcl-2 is an anti-apoptotic protein. The increased expression of Egr-1 and Bcl-2 by isoflurane was inhibited by ERK inhibition. Thus, our results suggest a role of ERK/Egr-1/Bcl-2 pathway in the isoflurane preconditioning-induced protection in the human neuroblastoma SH-SY5Y cells.

Butadienes↗
PubMed2006

T-cell tolerance or function is determined by combinatorial costimulatory signals.

Activated in immune responses, T lymphocytes differentiate into effector cells with potent immune function. CD28 is the most prominent costimulatory receptor for T-cell activation. However, absence of CD28 costimulation did not completely impair effector function of CD4 or CD8 T cells. Moreover, increasing number of costimulatory molecules are recently found on antigen-presenting cells to regulate T-cell activation. To understand the molecular mechanisms that determine T-cell function or tolerance, we have collectively examined the roles of positive and negative costimulatory molecules. Antigen-specific naïve CD4 and CD8 T cells, only when activated in the absence of both CD28 and ICOS pathways, were completely impaired in effector function. These tolerant T cells not only were anergic with profound defects in TcR signal transduction but also completely lacked expression of effector-specific transcription factors. T-cell tolerance induction in this system requires the action by negative costimulatory molecules; T-cell proliferation and function was partially restored by inhibiting PD-1, B7-H3 or B7S1. This work demonstrates that T-cell function or tolerance is controlled by costimulatory signals.

Animals↗
PubMed2006

Spontaneous transformation of CdTe nanoparticles into angled Te nanocrystals: from particles and rods to checkmarks, X-marks, and other unusual shapes.

CdTe nanoparticles spontaneously transform into the branched Te nanocrystals with the unique, highly anisotropic shape of checkmarks after partial removal of the stabilizers of L-cysteine. The Te checkmarks are made in a relatively high yield and uniformity; the length of the arms is ca. 150 nm, whereas the angle between the arms is 74 degrees . Subsequent growth of the particle yields mothlike nanocrystals retaining geometrical anisotropy. Unlike the previous synthesis methods of branched nanocrystals, they are formed via a merger of individual rod-shaped crystallites. High-energy crystal faces on their apexes act as the sticky points causing the particles to join in the ends. This is the first demonstration of spontaneous transformation of binary semiconductor particles into highly anisotropic nanocolloids in an angled conformation. The end reactivity of starting Te rods can be used both for bottom-up fabrication of nanoscale electronics and relatively safe and nontoxic method of synthesis of Te-based optical and other materials.

Cadmium↗
PubMed2006

The relation between D-galactose injection and mitochondrial DNA 4834 bp deletion mutation.

Since,D-galactose (D-gal) overload model has been used as a premature aging model, we hypothesized that it may also lead to accelerated aging in the inner ear. Furthermore, though the mitochondrial DNA (mtDNA) 4834 bp deletion mutation has been considered as the marker of aging, there is no information available in the literature concerning the mtDNA 4834 bp deletion mutation condition of the D-gal induced premature aging model. We investigate the changes in inner ear enzymatic activity, the occurring of mtDNA 4834 bp deletion in inner ear and other tissues and the relating hearing thresholds after the administration of high dosage (150 mg/kg per day) and low dosage (50 mg/kg per day) of D-gal to rats. Furthermore, the incidence of the mtDNA 4834 bp deletion in different tissues as well as in blood sample was compared. The results showed that daily subcutaneous injections of D-gal into rats for 8 weeks could lead to the biochemical defects and mtDNA 4834 bp deletion in the inner ear tissue and other tissues, which represent the typical aging animals, but the relating hearing threshold shifts (TS) were nearly identical in the three groups. This study also indicates that using of blood samples to detect mtDNA 4834 bp deletion in clinical research might lead to a 'false negative' result. A higher sensitive result could be gained using tissue biopsy to examine mtDNA 4834 bp deletion.

Aging↗
PubMed2006

Electrochemical catalytic treatment of wastewater by metal ion supported on cation exchange resin.

The electrochemical oxidation of phenol in synthetic wastewater and paper mill wastewater catalyzed by metal ion supported on cation exchange resin in suspended bed electrolytic reactor with graphite electrode has been investigated. The catalyst was characterized by SEM and XPS spectra and the effects of pH, the different metal ion and NaCl on the efficiency of the electrochemical oxidation phenol process were also studied. It was found that the catalyst containing Fe(3+) had the highest electrochemical catalytic activity for the electrochemical oxidation of phenol. When the initial concentration of phenol was 200 ppm, up to 90% chemical oxygen demand (COD) removal was obtained in 10 min. When the catalyst containing Fe(3+) was used to the paper mill wastewater, it still showed high efficiency. The COD removal could get to 75% in 60 min.

Catalysis↗
PubMed2006

Transforming growth factor-beta receptor type 1 (TGFbetaRI) kinase activity but not p38 activation is required for TGFbetaRI-induced myofibroblast differentiation and profibrotic gene expression.

Transforming growth factor-beta (TGFbeta) is a major mediator of normal wound healing and of pathological conditions involving fibrosis, such as idiopathic pulmonary fibrosis. TGFbeta also stimulates the differentiation of myofibroblasts, a hallmark of fibrotic diseases. In this study, we examined the underlying processes of TGFbetaRI kinase activity in myofibroblast conversion of human lung fibroblasts using specific inhibitors of TGFbetaRI (SD-208) and p38 mitogen-activated kinase (SD-282). We demonstrated that SD-208, but not SD-282, inhibited TGFbeta-induced SMAD signaling, myofibroblast transformation, and collagen gel contraction. Furthermore, we extended our findings to a rat bleomycin-induced lung fibrosis model, demonstrating a significant decrease in the number of myofibroblasts at fibroblastic foci in animals treated with SD-208 but not those treated with SD-282. SD-208 also reduced collagen deposition in this in vivo model. Microarray analysis of human lung fibroblasts identified molecular fingerprints of these processes and showed that SD-208 had global effects on reversing TGFbeta-induced genes involved in fibrosis, inflammation, cell proliferation, cytoskeletal organization, and apoptosis. These studies also revealed that although the p38 pathway may not be needed for appearance or disappearance of the myofibroblast, it can mediate a subset of inflammatory and fibrogenic events of the myofibroblast during the process of tissue repair and fibrosis. Our findings suggest that inhibitors such as SD-208 may be therapeutically useful in human interstitial lung diseases and pulmonary fibrosis.

Activin Receptors, Type I↗
PubMed2006

Delayed treatment with sildenafil enhances neurogenesis and improves functional recovery in aged rats after focal cerebral ischemia.

Increasing age decreases the number of new neurons in the dentate gyrus and the subventricular zone (SVZ). Sildenafil, a phosphodiesterase type 5 (PDE5) inhibitor, enhances neurogenesis in young rats. The present study tested the hypothesis that sildenafil augments neurogenesis in aged rats after focal cerebral ischemia. Nonischemic aged (18 months, n = 6) Wistar rats exhibited a significant reduction of actively proliferating and relatively quiescent cells in the SVZ measured by the number of minichromosome maintenance protein-2-positive (MCM-2+) cells, a marker of the proliferating cells, compared with nonischemic young (3-4 months, n = 8) rats. Occlusion of the middle cerebral artery did not increase the number of MCM-2+ cells in the SVZ of aged rats at 3 months after focal ischemia. However, treatment with sildenafil at a dose of 3 mg/kg (n = 8) daily for 7 consecutive days starting 7 days after focal ischemia significantly increased the number of MCM-2+ cells in the SVZ of aged rats compared with aged rats treated with saline (n = 8). Double immunostaining revealed that substantially more Ki67+ cells (a marker of proliferating cells) were doublecortin+ (a marker of migrating neuroblasts) in sildenafil-treated than in saline-treated aged animals. In addition, treatment with sildenafil significantly improved functional recovery compared with saline-treated rats. These data suggest that inhibition of PDE5 activity by sildenafil augments neurogenesis in the SVZ of aged ischemic rats, although these rats have reduced numbers of neural progenitor and stem cells in the SVZ.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed2006

Chemical characteristics of PM2.5 and PM10 in haze-fog episodes in Beijing.

Aerosol samples of PM2.5 and PM10 in a period of intensive haze-fog (HF) events were collected to investigate the chemical characteristics of air pollution in Beijing. The air quality in HF episodes was much worse than that in nonhaze-fog (NHF) days. The concentrations of elements and water-soluble (WS) ions (K+, So4(2-), and NO3-) in HF episodes were more than 10 times higher than those in NHF days. Most of the chemical species in PM2.5 and the secondary species (NH4+, So4(2-), and NO3-) in PM10 showed significant difference between HF from westerly direction (HFW) and southerly direction (HFS). The concentrations of secondary species in HFS were much higher than those in HFW, and other chemical species in HFS were lower than those in HFW. The sources of PM2.5 were more from areas on the regional scale due to its tendency for long-range transport, while PM10 was more limited to the local sources. Aerosol particles were more acidic in HFS and more alkaline in HFW. The secondary species were the major chemical components of the aerosol in HF episodes, and their concentrations increased in the order of NHF < HFW < HFS. High concentrations of the secondary aerosol in HF episodes were likely due to the higher sulfur and nitrogen oxidation rate in aqueous-phase reactions. The serious air pollution in HF episodes was strongly correlated with the meteorological conditions and the emissions of pollutants from anthropogenic sources.

Aerosols↗
PubMed2006

Direct dynamics study on hydrogen abstraction reaction of CF3CF2CH2OH with OH radical.

The dual-level direct dynamics method has been employed to investigate the H-abstraction reaction of CF(3)CF(2)CH(2)OH with OH radical, which is predicted to have two classes of possible reaction channels caused by different positions of hydrogen atom attack. The minimum-energy path is calculated at the B3LYP/6-311G(d,p) level, and the energetic information is further refined by the MC-QCISD method. To compare the structures, the other method MPW1K/6-311G(d,p) is also applied to this system. Hydrogen-bonded complexes are presented in the reactant and product sides of the three channels, indicating that each reaction may proceed via an indirect mechanism. The rate constants for each reaction channel are evaluated by canonical variational transition-state theory (CVT) with the small-curvature tunneling correction (SCT) over a wide range of temperatures from 200 to 2000 K. The calculated CVT/SCT rate constants are found to be in good agreement with the available experimental values. The result shows that the variational effect is small, and in the lower-temperature range, the SCT effect is important for each reaction. It is shown that hydrogen abstracted from the -CH(2)- position is the major channel, while H-abstraction from the -OH position may be neglected with the temperature increasing.

Journal Article↗