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Yi Wang

Publications and source records attributed to Yi Wang.

At least 55 records · Page 3Linked to original sources
PubMed2006

A protein kinase, interacting with two calcineurin B-like proteins, regulates K+ transporter AKT1 in Arabidopsis.

Potassium is an essential mineral element for plant growth and development. Although it is known that plants absorb and transport K+ through membrane transporters, it remains unclear how these transporters are regulated. Here we show that the protein kinase CIPK23, encoded by the LKS1 gene, regulates K+ uptake under low-K+ conditions. Lesion of LKS1 significantly reduced K+ uptake and caused leaf chlorosis and growth inhibition, whereas overexpression of LKS1 significantly enhanced K+ uptake and tolerance to low K+. We demonstrate that CIPK23 directly phosphorylates the K+ transporter AKT1 and further find that CIPK23 is activated by the binding of two calcineurin B-like proteins, CBL1 and CBL9. We propose a model in which the CBL1/9-CIPK23 pathway ensures activation of AKT1 and enhanced K+ uptake under low-K+ conditions.

Animals↗
PubMed2006

Role of complement component C5 in cerebral ischemia/reperfusion injury.

We evaluated the role of complement component C5 during the course of cerebral ischemic reperfusion injury in a rat model of middle cerebral artery occlusion (MCAO). Systemic C5 inhibition was achieved with an anti-C5 monoclonal antibody, which significantly prevented the deterioration of the motor functions by reducing cerebral lesion and edema. Our results show that activated C5 complement components played an important role in cerebral tissue inflammation resulting from ischemia/reperfusion injury.

Animals↗
PubMed2006

In vivo imaging of bone marrow mesenchymal stem cells transplanted into myocardium using magnetic resonance imaging: a novel method to trace the transplanted cells.

BACKGROUND: In vivo imaging of the cells transplanted into the beating heart is very important for the study of the cell's retention, migration. This study was designed to find a new labeling agent to trace and visualize the transplanted cells in vivo. METHOD: BMMSCs were incubated with SPIO for 48 h. The labeling efficiency was tested through Prussian blue staining, the growth ability was evaluated through MTT, and the cells viability was tested through Trypan blue rejection method, the migratory ability was assessed with Costar Transwell plates. After 10 days of coronary ligation of the Chinese mini swine, the labeled or unlabeled cells were transplanted into the myocardium. The MRI was carried out immediately and 1-4 weeks, respectively. After MRI the hearts were excised, the segment in which injections were performed were thin cut and stained with hematoxylin-eosin and Prussian blue staining. RESULTS: There were intracytoplasmatic blue particles in nearly every cell in the Prussian blue staining. SPIO had no poison effect on the cells' growth and proliferation. The cells' viability was more than 95%. The migratory ability was not affected. The injected sites containing labeled cells could all be detected through MRI and were confirmed on pathology. After 4 weeks the injected labeled cells could still be detected through MRI. The pathology showed the injected cells could survive in the MI area, and parallel in the same direction. CONCLUSION: The cells could be efficiently and safely labeled with SPIO and the labeled cells could be reliably detected by MRI in vivo.

Animals↗
PubMed2006

Site-specific preparation of 3-fluoro-1-substituted-naphthalenes via a novel base-catalyzed cyclization reaction from (E)-monofluoroenynes.

A novel cyclization reaction for the preparation of 3-fluoro-1-substituted-naphthalenes is reported. (E)-Monofluoroenynes, which are prepared by Sonogashira coupling reaction from (Z)-1-bromo-1-fluoroalkenes, undergo cyclization to afford 3-fluoro-1-substituted-naphthalenes in good to excellent yields when treated with DABCO or DBU in refluxing N-methyl-2-pyrrolidinone (NMP). [reaction: see text]

Journal Article↗
PubMed2006

Radiolabeling of MAG3-morpholino oligomers with 188Re at high labeling efficiency and specific radioactivity for tumor pretargeting.

We are investigating a novel pretargeting approach involving an initial IV injection of antitumor antibody conjugated with a phosphorodiamidate morpholino oligomer (MORF, a DNA analog) and the subsequent IV injection of the radiolabeled complement oligomer (cMORF). In this paper, the cMORF was labeled with (188)Re using MAG(3) as chelator for therapeutic applications. Since (c)MORFs are unstable in acidic condition, an optimal labeling pH was first selected and the other labeling factors were then examined. A labeling efficiency of greater than 90% can be achieved even at a concentration of MAG(3)-cMORF as low as 0.8 microM. The labeled cMORF is stable and capable of hybridizing to its complement.

Animals↗
PubMed2006

Interactions of hydrophobically modified polyvinylamine with pluronic triblock copolymer micelles.

The heats associated with the addition of triblock copolymers of ethylene oxide and propylene oxide (PEO-PPO-PEO pluronics) to solutions of linear polyvinylamine, with N-substituted pendant octyl groups (HMPVAm), were measured as functions of pH and pluronic structure. The interactions were exothermic with the overall enthalpy decreasing with increasing pH from 5 to 10. Surprisingly, the heat effect increased with increasing pluronic hydrophilicity; however, no enthalpy change was observed in the absence of micelles. The results were quantitatively modeled by assuming two competing processes-micellar dissolution and HMPVAm coating of micelles, preventing dissolution.

Journal Article↗
PubMed2006

Effects of benazepril on renal function and kidney expression of matrix metalloproteinase-2 and tissue inhibitor of metalloproteinase-2 in diabetic rats.

BACKGROUND: Excessive deposition of extracellular matrix (ECM) in the kidney is the hallmark of diabetic nephropathy. Increased matrix synthesis has been well documented but the effects of diabetes on degradative pathways, particularly in the in vivo setting. The renal protective effect of these pathways on matrix accumulation has not been fully elucidated. The present study was undertaken to investigate the activity of matrix metalloproteinase-2 (MMP-2), the expression of MMP-2 and tissue inhibitor of metalloproteinase-2 (TIMP-2) in kidney tissues of diabetic rats, and to explore the degradative pathway of type IV collagen (IV-C) and the renal protective effects of ACE inhibition-benazepril. METHODS: Twenty-four healthy male Wistar rats were divided randomly into normal control group (NC group), untreated diabetes mellitus group (DM group), and diabetes mellitus group treated with benazepril (DL group). The rat model of diabetes mellitus was induced by intraperitoneal injection of streptozocin (60 mg/kg). After the establishment of DM model, benazepril (10 mg.kg(-1).d(-1)) was given to the DL group for 12 weeks, and the same volume of water was given to the other two groups. At the end of 12 weeks, renal function was evaluated with 24-hour urinary protein (Upro), clearance of creatinine (Ccr), and blood urea nitrogen (BUN). MMP-2 activity was determined by gelatin zymography. The levels of MMP-2, TIMP-2 and collagen IV (IV-C) protein in the kidney tissue were assessed by immunohistochemistry. The gene expression of MMP-2 and TIMP-2 was measured by reverse transcription polymerase chain reaction (RT-PCR). RESULTS: The levels of BUN, Upro and Ccr in the DM group were higher than those in the NC group. In the DM group, the mRNA, enzymatic activity and proteins of MMP-2 decreased, but the expressions of IV-C and TIMP-2 increased. All diabetes-associated changes in renal function and MMP/TIMP were attenuated after benazepril treatment with reduced IV-C accumulation. CONCLUSIONS: The changes of MMP-2 and TIMP-2 expressions in kidney tissues of diabetes rats may contribute to the occurrence and progression of diabetic nephropathy. Benazepril could exert protective effects on diabetic nephropathy, owing to the upregulation of MMP-2 and downregulation of TIMP-2 expressions, which further inhibits the excessive deposition of extracellular matrix in the glomerulus.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed2006

The Mannich reaction of malonates with simple imines catalyzed by bifunctional cinchona alkaloids: enantioselective synthesis of beta-amino acids.

We describe the first efficient, direct asymmetric Mannich reactions with malonates and N-Boc aryl and alkyl imines by cooperative hydrogen-bonding catalysis with a cinchona alkaloid bearing a thiourea functionality. We have also extended the scope of this reaction to beta-ketoesters. The synthetic value of this new reaction is demonstrated in the establishment of a convergent enantioselective route toward the biologically important beta-amino acids under mild and air- and moisture-tolerant conditions.

Amino Acids↗
PubMed2006

[Study on the position of genes responsible for gallstone disease in Chinese population].

OBJECTIVE: To search the susceptibility genes of gallstone disease in Chinese population. METHODS: A genome wide scan was performed in twelve families with gallstone disease using fluorescence-labeled microsatellite markers. Genehunter and Batchlink of Linkage package were used for non- parameter and parameter linkage analysis to search the linkage loci on chromosomes. RESULTS: Four loci of D3S1266, D4S406, D9S1682 and D11S902 showed suggestive evidence for linkage. nonparametric linkage analysis (NPL)-score of D4S406 and D9S1682 was 1.77 (P = 0.05) and 1.92 (P = 0.04) respectively. The corresponding logarithm of the odds ratio (LOD)-score of D3S1266, D9S1682 were 1.35 and 2.07, and showed a rise of LOD-score from 1.35 to 2.71, 2.07 to 2.40 respectively when families with later-found patients or with higher triglyceride level were analyzed alone. Transmitted disequilibrium test of D11S902 showed a P-value of 0.0027. CONCLUSIONS: Chromosome 3, 4, 9 and 11 may contain genes involved in gallstone disease in Chinese population, and chromosome 3, 9 may hide genes that are liked to gallstone disease in families with later-found patients or with higher triglyceride concentration.

Age Factors↗
PubMed2006

Dual-function cinchona alkaloid catalysis: catalytic asymmetric tandem conjugate addition-protonation for the direct creation of nonadjacent stereocenters.

Catalytic tandem asymmetric reactions constitute a powerful strategy for the asymmetric construction of nonadjacent stereocenters in acyclic molecules directly from achiral precursors. In this Communication, we report a highly enantioselective and diastereoselective addition of trisubstituted carbon donors to 2-chloroacrylonitrile catalyzed by bifunctional cinchona alkaloid catalysts. This represents the first asymmetric tandem conjugate addition-protonation with efficient catalytic control of two nonadjacent stereocenters. As demonstrated in a concise and highly stereoselective formal total synthesis of (-)-manzacidin A, this asymmetric tandem reaction establishes a new and versatile catalytic approach for the enantioselective and diastereoselective creation of 1,3-tertiary-quaternary stereocenters.

Acrylonitrile↗
PubMed2006

Specific sequence motifs direct the oxygenation and chlorination of tryptophan by myeloperoxidase.

Most studies of protein oxidation have typically focused on the reactivity of single amino acid side chains while ignoring the potential importance of adjacent sequences in directing the reaction pathway. We previously showed that hypochlorous acid (HOCl), a specific product of myeloperoxidase, inactivates matrilysin by modifying adjacent tryptophan and glycine (WG) residues in the catalytic domain. Here, we use model peptides that mimic the region of matrilysin involved in this reaction, VVWGTA, VVWATA, and the library VVWXTA, to determine whether specific sequence motifs are targeted for chlorination or oxygenation by myeloperoxidase. Our results demonstrate that HOCl generated by myeloperoxidase or activated neutrophils converts the peptide VVWGTA to a chlorinated product, WG+32(Cl). Tandem mass spectrometry in concert with high resolution 1H and two-dimensional NMR analysis revealed that the modification required cross-linking of the tryptophan to the amide of glycine followed by chlorination of the indole ring of tryptophan. In contrast, when glycine in the peptide was replaced with alanine, the major products were mono- and dioxygenated tryptophan residues. When the peptide library VVWXTA (where X represents all 20 common amino acids) was exposed to HOCl, only WG produced a high yield of the chloroindolenine derivative. However, when glycine was replaced by other amino acids, oxygenated tryptophan derivatives were the major products. Our observations indicate that WG may represent a specific sequence motif in proteins that is targeted for chlorination by myeloperoxidase.

Amino Acid Motifs↗
PubMed2006

Complete sequence data support lack of balancing selection on PRNP in a natural Chinese population.

The M129V mutation in the human prion protein gene (PRNP) is the primary site linked to susceptibility to prion diseases in humans. The heterozygous state of this allele has been proven to be more resistant to prion-related diseases such as Creutzfeldt-Jakob disease. Based on a study of the common genetic variations, it has been proposed that balancing selection has played a critical role in shaping the distribution of 129V in worldwide populations. Kreitman and Di-Rienzo [Kreitman and Di-Rienzo (2004)Trend Genet 20:300-304] challenged this hypothesis by pointing out that the exclusion of polymorphisms with low frequency may introduce an ascertainment bias and, in turn, lead to a wrong conclusion. By studying sequence variations in samples from the Human Genome Diversity Project, Soldevila et al. [Soldevila et al. (2005) Trends Genet 21:389-391] showed that this ascertainment bias does exist. We argue that the evidence presented by Soldevila et al. may be compromised by the samples tested since they were selected from a population that may be substructured. In this study, we re-evaluated the hypothesis of balancing selection in a natural Chinese population using a much longer segment encompassing the entire genomic region of the PRNP gene (15 kb). We showed that the pattern of genetic variation in PRNP is not consistent with the presence of balancing selection in this gene.

Asian People↗
PubMed2006

In silico search of putative adverse drug reaction related proteins as a potential tool for facilitating drug adverse effect prediction.

Adverse drug reaction (ADR) is a significant issue in drug development and post-market applications. Different experimental and computational approaches need to be explored for predicting ADRs due to the complexity of their molecular mechanisms. One approach for predicting ADRs of a drug is to search for its interaction with ADR-related proteins (ADRRPs). In this work, this approach is tested on 11 marketed anti-HIV drugs covering protease inhibitors (PIs), nucleoside reverse transcriptase inhibitors (NRTIs), and non-nucleoside reverse transcriptase inhibitors (NNRTIs). An in silico drug target search method, INVDOCK, is used for searching the ADRRPs of each of these drugs. The corresponding ADRs of the predicted ADRRPs of each of these drugs are compared to clinically observed ADRs reported in the literature. It is found that 86-89% of the INVDOCK predicted ADRs of these drugs are consistent with the literature reported ADRs, and about 67-100% of the literature-reported ADRs of these drugs to various degrees is agreed with INVDOCK predictions. These results suggest that it is feasible to explore in silico ADRRP search methods for facilitating drug toxicity prediction.

Adverse Drug Reaction Reporting Systems↗
PubMed2006

A causal relationship discovery-based approach to identifying active components of herbal medicine.

Herbal medicine is widely applied for clinical use in East Asia and other countries. However, unclear correlation between its complex chemical composition and bioactivity prevents its application in the West. In the present study, a stepwise causal adjacent relationship discovery algorithm has been developed to study correlation between composition and bioactivity of herbal medicine and identify active components from the complex mixture. This approach was successfully applied in discovering active constituents from mixed extracts of Radix Salviae miltiorrhizae and Cortex Moutan. Moreover, advantage of the present approach compared with bioassay-guided isolation was demonstrated by its application on a typical herbal drug. The current work offers a new way to virtually screen active components of herbal medicine, and it might be helpful to accelerate the process of new drug discovery from natural products.

Algorithms↗
PubMed2006

Copper(I)-only catalyzed reactions of (E)-2,3-difluoro-3-stannylacrylic ester with acid chlorides and mechanistic studies of the "copper effect" in stille coupling reactions.

[reaction: see text] The reactions of (E)-2,3-difluoro-3-stannylacrylic ester with acid chlorides under catalysis of CuI stereospecifically afforded ethyl (2Z)-2,3-difluoro-4-oxo-substituted 2-butenoates in good yields. Moreover, direct spectroscopic observation of the corresponding organocopper reagent was observed for the first time in Stille coupling reactions of organostannanes.

Journal Article↗
PubMed2006

[Spleen-preserving distal pancreatectomy in treatment of solid-pseudopapillary neoplasm].

OBJECTIVE: To investigate the feasibility and safety of spleen-preserving distal pancreatectomy with conservation of the splenic arteries and veins in treatment of benign neoplasms of distal pancreas. METHODS: Four patients with solid-pseudopapillary neoplasm, 1 males and 3 females, aged 30 (17 - 37), underwent laparotomy. The distal pancreas with tumor was cut. The perforating branches between the splenic artery and vein and the distal pancreas were isolated, ligated, and cut. The splenic artery and vein and the short and left gastric vessels were all preserved. The spleen remained intact. RESULTS: The mean operation time was 208 minutes +/- 52 minutes, and the mean blood loss was 475 ml +/- 96 ml. Blood transfusion was not necessary. The mean post-operative hospital stay was 18 days +/- 13 days. No post-operative complications were found except for pancreatic leakage occurring in one patient that was cured by conservative treatment. No metastasis and recurrence was found. CONCLUSION: Safe and feasible, spleen-preserving distal pancreatectomy with conservation of the splenic arteries and veins is one of the best choices for treatment of benign and borderline tumors of pancreas.

Adolescent↗
PubMed2006

Akt binds to and phosphorylates phospholipase C-gamma1 in response to epidermal growth factor.

Both phospholipase (PL) C-gamma1 and Akt (protein kinase B; PKB) are signaling proteins that play significant roles in the intracellular signaling mechanism used by receptor tyrosine kinases, including epidermal growth factor (EGF) receptor (EGFR). EGFR activates PLC-gamma1 directly and activates Akt indirectly through phosphatidylinositol 3-kinase (PI3K). Many studies have shown that the PLC-gamma1 pathway and PI3K-Akt pathway interact with each other. However, it is not known whether PLC-gamma1 binds to Akt directly. In this communication, we identified a novel interaction between PLC-gamma1 and Akt. We demonstrated that the interaction is mediated by the binding of PLC-gamma1 Src homology (SH) 3 domain to Akt proline-rich motifs. We also provide a novel model to depict how the interaction between PLC-gamma1 SH3 domain and Akt proline-rich motifs is dependent on EGF stimulation. In this model, phosphorylation of PLC-gamma1 Y783 by EGF causes the conformational change of PLC-gamma1 to allow the interaction of its SH3 domain with Akt proline-rich motifs. Furthermore, we showed that the interaction between PLC-gamma1 and Akt resulted in the phosphorylation of PLC-gamma1 S1248 by Akt. Finally, we showed that the interaction between PLC-gamma1 and Akt enhanced EGF-stimulated cell motility.

Amino Acid Motifs↗