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Kang S, Miao GX, Shi S, Jia Z, Nikles DE, Harrell JW. Enhanced Magnetic Properties of Self-Assembled FePt Nanoparticles with MnO Shell. J Am Chem Soc 2006; 128:1042-3. [PMID: 16433497 DOI: 10.1021/ja057343n] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Self-assembled FePt/MnO nanoparticles with different morphology and size were synthesized with a polyol process. With the MnO coating, FePt nanoparticles exhibit a high blocking temperature and magnetic moment. The low-temperature hysteresis loop of FePt nanoparticles can be shifted through the AFM pinning of the MnO shell. The aggregation of FePt nanoparticles during the L10 phase transformation can be significantly decreased by coating with the MnO shell.
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Chang J, Zhang C, Tani-Ishii N, Shi S, Wang CY. NF-kappaB activation in human dental pulp stem cells by TNF and LPS. J Dent Res 2005; 84:994-8. [PMID: 16246929 PMCID: PMC1764452 DOI: 10.1177/154405910508401105] [Citation(s) in RCA: 101] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Post-natal human dental pulp stem cells (DPSCs) represent a unique precursor population in the dental pulp, which has multipotential and can regenerate a dentin/pulp-like structure. Because the dental pulp is frequently infected by oral bacteria due to dental decay, in this study, we examined whether lipopolysaccharide (LPS) and tumor necrosis factor (TNF) activated the immunologic transcription factor nuclear factor kappa B (NF-kappaB) in DPSCs. We found that both TNF and LPS activated the I-kappa B kinase complex (IKK) in DPSCs to induce the phosphorylation and degradation of IkappaBalpha, resulting in the nuclear translocation of NF-kappaB. Consistently, both TNF and LPS rapidly induced the expression of the NF-kappaB-dependent gene interleukin-8 (IL-8). However, unlike in monocytes, we found that LPS could not induce the phosphorylation of the NF-kappaB active subunit p65 in DPSCs. In summary, our studies suggest that DPSCs may be involved in immune responses during pulpal infection through activating NF-kappaB.
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178
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Seo BM, Miura M, Sonoyama W, Coppe C, Stanyon R, Shi S. Recovery of stem cells from cryopreserved periodontal ligament. J Dent Res 2005; 84:907-12. [PMID: 16183789 DOI: 10.1177/154405910508401007] [Citation(s) in RCA: 149] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Human post-natal stem cells possess a great potential to be utilized in stem-cell-mediated clinical therapies and tissue engineering. It is not known whether cryopreserved human tissues contain functional post-natal stem cells. In this study, we utilized human periodontal ligament to test the hypothesis that cryopreserved human periodontal ligament contains retrievable post-natal stem cells. These cryopreserved periodontal ligament stem cells maintained normal periodontal ligament stem cell characteristics, including expression of the mesenchymal stem cell surface molecule STRO-1, single-colony-strain generation, multipotential differentiation, cementum/periodontal-ligament-like tissue regeneration, and a normal diploid karyotype. Collectively, this study provides valuable evidence demonstrating a practical approach to the preservation of solid-frozen human tissues for subsequent post-natal stem cell isolation and tissue regeneration. The present study demonstrates that human post-natal stem cells can be recovered from cryopreserved human periodontal ligament, thereby providing a practical clinical approach for the utilization of frozen tissues for stem cell isolation.
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179
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Blackmore T, Hererra G, Shi S, Bridgewater P, Wheeler L, Byrne J. Characterization of prolyl iminopeptidase-deficient Neisseria gonorrhoeae. J Clin Microbiol 2005; 43:4189-90. [PMID: 16081973 PMCID: PMC1233950 DOI: 10.1128/jcm.43.8.4189-4190.2005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Prolyl iminopeptidase (PIP) is an enzyme produced by Neisseria gonorrhoeae, the detection of which is incorporated into several commercial test panels. In this report we describe two distinct mutations in the pip gene which account for the loss of PIP activity.
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Shi S, Bartold PM, Miura M, Seo BM, Robey PG, Gronthos S. The efficacy of mesenchymal stem cells to regenerate and repair dental structures. Orthod Craniofac Res 2005; 8:191-9. [PMID: 16022721 DOI: 10.1111/j.1601-6343.2005.00331.x] [Citation(s) in RCA: 323] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
OBJECTIVES Identification, characterization, and potential application of mesenchymal stem cells (MSC) derived from human dental tissues. METHODS Dental pulp and periodontal ligament were obtained from normal human impacted third molars. The tissues were digested in collagenase/dispase to generate single cell suspensions. Cells were cultured in alpha-MEM supplemented with 20% fetal bovine serum, 2 mM l-glutamine, 100 microM l-ascorbate-2-phosphate. Magnetic and fluorescence activated cell sorting were employed to characterize the phenotype of freshly isolated and ex vivo expanded cell populations. The developmental potential of cultured cells was assessed following co-transplantation with hydroxyapetite/tricalcium phosphate (HA/TCP) particles into immunocompromised mice for 8 weeks. RESULTS MSC were identified in adult human dental pulp (dental pulp stem cells, DPSC), human primary teeth (stem cells from human exfoliated deciduous teeth, SHED), and periodontal ligament (periodontal ligament stem cells, PDLSC) by their capacity to generate clongenic cell clusters in culture. Ex vivo expanded DPSC, SHED, and PDLSC populations expressed a heterogeneous assortment of makers associated with MSC, dentin, bone, smooth muscle, neural tissue, and endothelium. PDLSC were also found to express the tendon specific marker, Scleraxis. Xenogeneic transplants containing HA/TCP with either DPSC or SHED generated donor-derived dentin-pulp-like tissues with distinct odontoblast layers lining the mineralized dentin-matrix. In parallel studies, PDLSC generated cementum-like structures associated with PDL-like connective tissue when transplanted with HA/TCP into immunocompromised mice. CONCLUSION Collectively, these data revealed the presence of distinct MSC populations associated with dental structures with the potential of stem cells to regenerate living human dental tissues in vivo.
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Shi S, Kuroda S, Hosoi K, Kubota H. Poly(methyl methacrylate)/polyacrylonitrile composite latex particles with a novel surface morphology. POLYMER 2005. [DOI: 10.1016/j.polymer.2005.02.106] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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182
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Batouli S, Miura M, Brahim J, Tsutsui TW, Fisher LW, Gronthos S, Robey PG, Shi S. Comparison of stem-cell-mediated osteogenesis and dentinogenesis. J Dent Res 2004; 82:976-81. [PMID: 14630898 DOI: 10.1177/154405910308201208] [Citation(s) in RCA: 268] [Impact Index Per Article: 13.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
The difference between stem-cell-mediated bone and dentin regeneration is not yet well-understood. Here we use an in vivo stem cell transplantation system to investigate differential regulation mechanisms of bone marrow stromal stem cells (BMSSCs) and dental pulp stem cells (DPSCs). Elevated expression of basic fibroblast growth factor (bFGF) and matrix metalloproteinase 9 (MMP-9, gelatinase B) was found to be associated with the formation of hematopoietic marrow in BMSSC transplants, but not in the connective tissue of DPSC transplants. The expression of dentin sialoprotein (DSP) specifically marked dentin synthesis in DPSC transplants. Moreover, DPSCs were found to be able to generate reparative dentin-like tissue on the surface of human dentin in vivo. This study provided direct evidence to suggest that osteogenesis and dentinogenesis mediated by BMSSCs and DPSCs, respectively, may be regulated by distinct mechanisms, leading to the different organization of the mineralized and non-mineralized tissues.
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183
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Dawson AG, Lockett P, Shi S. Tsunami hazards in Europe. ENVIRONMENT INTERNATIONAL 2004; 30:577-585. [PMID: 15031018 DOI: 10.1016/j.envint.2003.10.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/01/2003] [Accepted: 10/01/2003] [Indexed: 05/24/2023]
Abstract
Tsunami represents one of the most potentially serious forms of coastal flood risk. Although much is known on the recorded history of tsunamis for given areas of the world, very little information is available on the occurrence of palaeotsunamis during prehistory. This is of fundamental importance in calculating tsunami flood risk for any given coastal area. Given sufficient information on past tsunami activity for a particular coastal area, the numerical calculation of aggregate coastal flood risk (including tsunami) for a coastal area is very difficult to estimate since one needs also to take into account the risk of a tsunami and a storm surge taking place simultaneously during a high tide. Estimates of coastal flood risk also need to consider future changes in relative sea level caused by the combined effects of global climate change and vertical movements of the lithosphere.
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Bustamante F, Enick RM, Cugini A, Killmeyer RP, Howard BH, Rothenberger KS, Ciocco MV, Morreale BD, Chattopadhyay S, Shi S. High-temperature kinetics of the homogeneous reverse water-gas shift reaction. AIChE J 2004. [DOI: 10.1002/aic.10099] [Citation(s) in RCA: 172] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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185
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Reichelt M, Shi S, Hayes M, Kay G, Batch J, Gole GA, Browning J. Vascular endothelial growth factor-B and retinal vascular development in the mouse. Clin Exp Ophthalmol 2003; 31:61-5. [PMID: 12580897 DOI: 10.1046/j.1442-9071.2003.00602.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
PURPOSE Vascular endothelial growth factor-A (VEGF-A) is crucial to retinal vascular growth, both normal and pathological. VEGF-B, recently characterized, is reported to be expressed in retinal tissues, but the importance of VEGF-B to retinal vascular development remained unknown. The aim of this study was to analyse retinal vascular growth in the Vegfb-/- knockout mouse. METHODS Retinal vascular growth was measured in Vegfb-/- knockout mice raised under normal conditions, and Vegfb-/- knockout mice with an oxygen-induced proliferative retinopathy. Wild type Vegfb+/+ mice served as controls. Vessels were perfused with ink and retinal flatmounts secondarily labelled with FITC-lectin (BS-1, Griffonia simplicifolia). Area and diameter of retinal growth and retinal vascular growth were recorded over days 0-20, and capillary density and mean diameter recorded from day 17 pups. RESULTS A variety of techniques confirmed that Vegfb+/+ mice expressed VEGF-B and that VEGF-B expression was absent in Vegfb-/- mice. Vegfb-/- mice raised in room air showed no significant differences from Vegfb+/+ controls. No differences were found in oxygen-induced retinopathy between Vegfb-/- and Vegfb+/+ pups in either the extent of the initial oxygen-induced ablation, or in the regrowth of retinal vessels or vitreal (neovascular) sprouts; vitreal sprouts are important markers of the abnormal proliferative response, and are maximally expressed on day 17 in this model of oxygen-induced retinopathy. CONCLUSIONS These results indicate that a lack of VEGF-B does not significantly affect development of the retinal vasculature under normal conditions, nor does it appear to affect the proliferative retinal responses seen in oxygen-induced retinopathy.
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186
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Gronthos S, Brahim J, Li W, Fisher LW, Cherman N, Boyde A, DenBesten P, Robey PG, Shi S. Stem cell properties of human dental pulp stem cells. J Dent Res 2002; 81:531-5. [PMID: 12147742 DOI: 10.1177/154405910208100806] [Citation(s) in RCA: 1361] [Impact Index Per Article: 61.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
In this study, we characterized the self-renewal capability, multi-lineage differentiation capacity, and clonogenic efficiency of human dental pulp stem cells (DPSCs). DPSCs were capable of forming ectopic dentin and associated pulp tissue in vivo. Stromal-like cells were reestablished in culture from primary DPSC transplants and re-transplanted into immunocompromised mice to generate a dentin-pulp-like tissue, demonstrating their self-renewal capability. DPSCs were also found to be capable of differentiating into adipocytes and neural-like cells. The odontogenic potential of 12 individual single-colony-derived DPSC strains was determined. Two-thirds of the single-colony-derived DPSC strains generated abundant ectopic dentin in vivo, while only a limited amount of dentin was detected in the remaining one-third. These results indicate that single-colony-derived DPSC strains differ from each other with respect to their rate of odontogenesis. Taken together, these results demonstrate that DPSCs possess stem-cell-like qualities, including self-renewal capability and multi-lineage differentiation.
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187
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Yang X, Shi S, Ling J. [Studies on voice identification]. FA YI XUE ZA ZHI 2002; 14:224-5, 228, 252. [PMID: 11938906] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/24/2023]
Abstract
The spectrographic method of voice identification was investigated and its application in forensic sciences was discussed.
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188
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Chen ZR, Hou HW, Xin XQ, Yu KB, Shi S. A Half-Open Cage-Shaped Cluster, (NEt4)3[WOS3(CuBr)3(.mu.2-Br)].cntdot.2H2O: Synthesis, Structure, and Nonlinear Optical Properties. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100021a042] [Citation(s) in RCA: 88] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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189
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Shi S, Ji W, Tang SH, Lang JP, Xin XQ. Synthesis and Optical Limiting Capability of Cubane-like Mixed Metal Clusters (n-Bu4N)3[MoAg3BrX3S4] (X = Cl and I). J Am Chem Soc 2002. [DOI: 10.1021/ja00087a064] [Citation(s) in RCA: 240] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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190
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Shi S, Wudl F. Synthesis and some properties of 11,12-diaminodibenzo[b,g][1,8]naphthyridine. J Org Chem 2002. [DOI: 10.1021/jo00257a040] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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191
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Shi S, Zhang X, Shi XF. Large Nonlinear Optical Effects and Small Linear Absorption of Inorganic Clusters (Me4N)2[Cu4(SPh)6] and (Me4N)2[Ag6(SPh)8]. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100041a002] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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192
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Wooley KL, Hawker CJ, Frechet JMJ, Wudl F, Srdanov G, Shi S, Li C, Kao M. Fullerene-bound dendrimers: soluble, isolated carbon clusters. J Am Chem Soc 2002. [DOI: 10.1021/ja00074a075] [Citation(s) in RCA: 142] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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193
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Shi S, Hou HW, Xin XQ. Solid State Synthesis and Self-Focusing and Nonlinear Absorptive Properties of Two Butterfly-Shaped Clusters WCu2OS3(PPh3)4 and MoCu2OS3(PPh3)3. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100012a027] [Citation(s) in RCA: 90] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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194
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Shi S, Ji W, Xin XQ. Synthesis and Superior Third-Order Nonlinear Optical Properties of the Cluster (n-Bu4N)4[Mo8Cu12O8S24]. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100003a010] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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195
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Ji W, Shi S, Du HJ, Ge P, Tang SH, Xin XQ. Optical Power Limiting with Solutions of Hexagonal Prism Cage Shaped Transition-Metal Cluster Mo2Ag4S8(PPh3)4. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100048a001] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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196
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Shi S, Khemani KC, Li Q, Wudl F. A polyester and polyurethane of diphenyl C61: retention of fulleroid properties in a polymer. J Am Chem Soc 2002. [DOI: 10.1021/ja00052a083] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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197
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Shi S, Ji W, Lang JP, Xin XQ. New Nonlinear Optical Chromophore: Synthesis, Structures, and Optical Limiting Effect of Transition-Metal Clusters (n-Bu4N)3[WM3Br4S4] (M = Cu and Ag). ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100065a005] [Citation(s) in RCA: 116] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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198
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Parinandi NL, Roy S, Shi S, Cummings RJ, Morris AJ, Garcia JG, Natarajan V. Role of Src kinase in diperoxovanadate-mediated activation of phospholipase D in endothelial cells. Arch Biochem Biophys 2001; 396:231-43. [PMID: 11747302 DOI: 10.1006/abbi.2001.2609] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have shown earlier that oxidant-induced activation of phospholipase D (PLD) in vascular endothelial cells (ECs) is regulated by protein tyrosine kinases. To further understand the regulation of oxidant-induced PLD activation, we investigated the role of Src kinase. Treatment of bovine pulmonary artery ECs (BPAECs) with a model oxidant, diperoxovanadate (DPV), at 5 microM concentration, for 30 min, stimulated PLD activity (four- to eightfold), which was attenuated by tyrosine kinase inhibitors and by Src kinase-specific inhibitors PP-1 and PP-2, in a dose- and time-dependent fashion. Furthermore, BPAECs exposed to DPV (5 microM) for 2 min showed activation of Src kinase as observed by increased tyrosine phosphorylation and autophosphorylation in Src immunoprecipitates, which was attenuated by PP-2. Src immunoprecipitates of cell lysates from control BPAECs exhibited PLD activity in cell-free preparations, which was Arf- and Rho-sensitive and was enhanced at 2 min of DPV (5 microM) treatment. Also, Western blots of Src immunoprecipitates of control cells revealed the presence of PLD(1) and PLD(2), suggesting the association of PLD with Src kinase under basal conditions. However, exposure of cells to DPV (5 microM) for 2 min enhanced the association of PLD(2) but not PLD(1) with Src. Western blotting of immunoprecipitates of PLD(1) and PLD(2) isoforms of control BPAECs revealed the presence of Src under basal conditions and exposure of cells to DPV (5 microM) for 2 min enhanced the association of PLD(2) with Src in PLD(2) immunoprecipitates. Transient expression of a dominant negative mutant of Src in BPAECs attenuated DPV- but not TPA-induced PLD activation. In cell-free preparations, Src did not phosphorylate either PLD(1) or PLD(2) compared to protein kinase Calpha or p38 mitogen-activated protein kinase. These data show for the first time a direct association of Src with PLD in ECs and regulation of PLD in intact cells.
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Abstract
We compared the gene expression profiles of human dental pulp stem cells (DPSCs) and bone marrow stromal stem cells (BMSSCs) as representative populations of odontoprogenitor and osteoprogenitor cells, respectively. Total RNA from primary cultures was reverse-transcribed to generate cDNA probes and then hybridized with the Research Genetics human gene microarray filter GF211. The microarrays were analyzed using the PATHWAYS software package. Human DPSCs and BMSSCs were found to have a similar level of gene expression for more than 4000 known human genes. A few differentially expressed genes, including collagen type XVIII alpha1, insulin-like growth factor-2 (IGF-2), discordin domain tyrosine kinase 2, NAD(P)H menadione oxidoreductase, homolog 2 of Drosophila large disk, and cyclin-dependent kinase 6 were highly expressed in DPSCs, whereas insulin-like growth factor binding protein-7 (IGFBP-7), and collagen type I alpha2 were more highly expressed in BMSSCs. Furthermore, we confirmed the differential expression of these genes by semiquantitative polymerase chain reaction (PCR) and northern blot hybridization. The protein expression patterns for both IGF-2 and IGFBP-7 correlated with the differential mRNA levels seen between DPSCs and BMSSCs. This report describes the gene expression patterns of two distinct precursor populations associated with mineralized tissue, and provides a basis for further characterization of the functional roles for many of these genes in the development of dentin and bone.
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Liu J, Zhao X, Meng Y, Shen J, Xue Y, Shi S, Cai Y. Expression and deletion analysis of EcoRII endonuclease and methylase gene. CHINESE MEDICAL SCIENCES JOURNAL = CHUNG-KUO I HSUEH K'O HSUEH TSA CHIH 2001; 16:200-3. [PMID: 12903755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/04/2023]
Abstract
OBJECTIVE To clone complete EcoRII restriction endonuclease gene (ecoRIIR) and methyltransferase gene (ecoRIIM) in one vector and to analyze the coordinating expression of this whole R-M system. METHODS Unidirectional deletion subclones were constructed with ExoIII. ecoRIIR/ M genes were preliminarily located in the cloned fragment according to the enzyme activities of subclones. Exact deletion sites were determined by sequencing, and transcriptional start sites were determined by S1 mapping. RESULTS The DNA fragment which was cloned into pBluescript SK + contained intact ecoRIIR gene and ecoRIIM gene, and two transcriptional start sites of ecoRIIR gene were determined. 132bp to 458bp from 3'end of ecoRIIR gene are indispensable to enzyme activities and deletion of 202bp from 3' end of ecoRIIM gene made enzyme lose the capability in DNA protection to resist specific cut with EcoRII endonuclease (EcoRII. R). Deletion of the coding and flanking sequences of one gene did not affect the expression of the other gene, and the recombinants only containing ecoRIIR gene appeared to be lethal to dcm+ host. CONCLUSION ecoRIIM gene linking closely to ecoRIIR gene is very important for the existence of the R-M system in process of evolution, but the key to control EcoRII R-M order may not exist in transcriptional level .
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