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Wang J, Yoo Y, Gao C, Takeuchi I, Sun X, Chang H, Xiang X, Schultz PG. Identification of a blue photoluminescent composite material from a combinatorial library. Science 1998; 279:1712-4. [PMID: 9497288 DOI: 10.1126/science.279.5357.1712] [Citation(s) in RCA: 241] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A quaternary combinatorial masking strategy was used in conjunction with photolithography to generate compositionally diverse thin-film phosphor libraries containing 1024 different compositions on substrates 2.5 centimeters square. A parallel imaging system and scanning spectrophotometer were used to identify and characterize compositions in the library with interesting luminescent behavior. Optimal compositions were identified with the use of gradient libraries, in which the stoichiometry of a material was varied continuously. This process led to the identification of an efficient blue photoluminescent composite material, Gd3Ga5O12/SiO2. Experimental evidence suggests that luminescence in this material may arise from interfacial effects between SiO2 and Gd3Ga5O12.
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Zou Z, Gao C, Nagaich AK, Connell T, Saito S, Moul JW, Seth P, Appella E, Srivastava S. p53 regulates the expression of the tumor suppressor gene maspin. J Biol Chem 2000; 275:6051-4. [PMID: 10692390 DOI: 10.1074/jbc.275.9.6051] [Citation(s) in RCA: 194] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Maspin has been shown to inhibit tumor cell invasion and metastasis in breast tumor cells. Maspin expression was detected in normal breast and prostate epithelial cells, whereas tumor cells exhibited reduced or no expression. However, the regulatory mechanism of maspin expression remains unknown. We report here a rapid and robust induction of maspin expression in prostate cancer cells (LNCaP, DU145, and PC3) and breast tumor cells (MCF7) following wild type p53 expression from an adenovirus p53 expression vector (AdWTp53). p53 activates the maspin promoter by binding directly to the p53 consensus-binding site present in the maspin promoter. DNA-damaging agents and cytotoxic drugs induced endogenous maspin expression in cells containing the wild type p53. Maspin expression was refractory to the DNA-damaging agents in cells containing mutant p53. These results, combined with recent studies of the tumor metastasis suppressor gene KAI1 and plasminogen activator inhibitor 1 (PAI1), define a new category of molecular targets of p53 that have the potential to negatively regulate tumor invasion and/or metastasis.
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Xu L, Daly T, Gao C, Flotte TR, Song S, Byrne BJ, Sands MS, Parker Ponder K. CMV-beta-actin promoter directs higher expression from an adeno-associated viral vector in the liver than the cytomegalovirus or elongation factor 1 alpha promoter and results in therapeutic levels of human factor X in mice. Hum Gene Ther 2001; 12:563-73. [PMID: 11268288 DOI: 10.1089/104303401300042500] [Citation(s) in RCA: 136] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Although AAV vectors show promise for hepatic gene therapy, the optimal transcriptional regulatory elements have not yet been identified. In this study, we show that an AAV vector with the CMV enhancer/chicken beta-actin promoter results in 9.5-fold higher expression after portal vein injection than an AAV vector with the EF1 alpha promoter, and 137-fold higher expression than an AAV vector with the CMV promoter/enhancer. Although induction of the acute-phase response with the administration of lipopolysaccharide (LPS) activated the CMV promoter/enhancer from the context of an adenoviral vector in a previous study, LPS resulted in only a modest induction of this promoter from an AAV vector in vivo. An AAV vector with the CMV-beta-actin promoter upstream of the coagulation protein human factor X (hFX) was injected intravenously into neonatal mice. This resulted in expression of hFX at 548 ng/ml (6.8% of normal) for up to 1.2 years, and 0.6 copies of AAV vector per diploid genome in the liver at the time of sacrifice. Neonatal intramuscular injection resulted in expression of hFX at 248 ng/ml (3.1% of normal), which derived from both liver and muscle. We conclude that neonatal gene therapy with an AAV vector with the CMV-beta-actin promoter might correct hemophilia due to hFX deficiency.
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Long Y, Liang J, Xu H, Huang Q, Yang J, Gao C, Qiu W, Lin S, Chen X. Autoimmune glial fibrillary acidic protein astrocytopathy in Chinese patients: a retrospective study. Eur J Neurol 2018; 25:477-483. [PMID: 29193473 DOI: 10.1111/ene.13531] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Accepted: 11/02/2017] [Indexed: 12/17/2022]
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Wang JYJ, Zhou DHD, Li J, Zhang M, Deng J, Tang M, Gao C, Li J, Lian Y, Chen M. Leisure activity and risk of cognitive impairment: The Chongqing aging study. Neurology 2005; 66:911-3. [PMID: 16291928 DOI: 10.1212/01.wnl.0000192165.99963.2a] [Citation(s) in RCA: 130] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
The authors followed 5,437 people aged 55 years and older with normal baseline Mini-Mental State Examination score annually for 5 years. The mean incidence of cognitive impairment was 2.3% per year. Cognitive activities in both the individual item (playing board games and reading) and the composite measure were associated with the reduced risk of cognitive impairment, while watching television was associated with an increased risk of cognitive impairment.
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Gao P, Xing AY, Zhou GY, Zhang TG, Zhang JP, Gao C, Li H, Shi DB. The molecular mechanism of microRNA-145 to suppress invasion-metastasis cascade in gastric cancer. Oncogene 2013; 32:491-501. [PMID: 22370644 DOI: 10.1038/onc.2012.61] [Citation(s) in RCA: 127] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 01/20/2012] [Accepted: 01/22/2012] [Indexed: 02/06/2023]
Abstract
Invasion and metastasis are the major features of malignant tumors that are responsible for 90% of cancer-related deaths. Recently, microRNAs have been discovered to have a role in suppressing tumor metastasis. This study's aim was to clarify the roles of miR-145 in gastric carcinomas and its underlying molecular mechanism in regulating tumor metastasis. Here, we demonstrate a stepwise downregulation of miR-145 level in nontumorous gastric mucosa, primary gastric cancers and their secondary metastases. In vitro analysis of miR-145's ectopic expression and loss-of-function suggests that it suppresses gastric cancer cell migration and invasion. In vivo spontaneous metastasis and experimental metastasis assay further confirm its function in suppressing the invasion-metastasis cascade, including impairing local invasion and inhibiting hematogenous metastasis in gastric cancers. Furthermore, we identified a novel mechanism of miR-145 to suppress metastasis. N-cadherin (CDH2) was proved to be a direct target of miR-145, using luciferase assay and western blot. Re-expressing N-cadherin in miR-145-transfected cells reverses their migration and invasion defects. Although not a direct target of miR-145, matrix metallopeptidase 9 (MMP9), but not MMP2, was also significantly decreased in miR-145-expressing cells. We suggest that miR-145 suppresses tumor metastasis by inhibiting N-cadherin protein translation, and then indirectly downregulates its downstream effector MMP9.
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Noda K, Miyoshi E, Uozumi N, Yanagidani S, Ikeda Y, Gao C, Suzuki K, Yoshihara H, Yoshikawa K, Kawano K, Hayashi N, Hori M, Taniguchi N, Yoshikawa M. Gene expression of alpha1-6 fucosyltransferase in human hepatoma tissues: a possible implication for increased fucosylation of alpha-fetoprotein. Hepatology 1998; 28:944-52. [PMID: 9755230 DOI: 10.1002/hep.510280408] [Citation(s) in RCA: 112] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The 1-6 fucosylated -fetoprotein (AFP) present in serum of patients with hepatocellular carcinoma (HCC) has been employed for the differential clinical diagnosis of HCC from chronic liver diseases. The molecular mechanism by which this alteration occurs, however, remains largely unknown. To address this issue, we purified GDP-L-Fuc:N-acetyl-beta-D-glucosaminide 1-6 fucosyltransferase (1-6 FucT), an enzyme involved in the 1-6 fucosylation of N-glycans from porcine brain, as well as from a human gastric cancer cell line, and cloned their genes. In this study, levels of 1-6 FucT mRNA expression and the activity of this enzyme for 12 human HCC tissues were examined and compared with that in surrounding tissues and normal livers. The mean +/- SD for 1-6 FucT activity was 78 +/- 41 pmol/h/mg in normal control liver, 202 +/- 127 pmol/h/mg in adjacent uninvolved liver tissues (chronic hepatitis: 181 +/- 106 pmol/h/mg; liver cirrhosis: 233 +/- 164 pmol/h/mg), and 195 +/- 72 pmol/h/mg in HCC tissues. The mRNA expression of 1-6 FucT was also enhanced in proportion to enzymatic activity except for a few cases, suggesting that 1-6 FucT expression is increased in chronic liver diseases, especially liver cirrhosis. Transfection of 1-6 FucT gene into cultured rat hepatocytes markedly increased 1-6 FucT activity and led to an increase in lens culinaris agglutinin (LCA) binding proteins in both cell lysates and condition media. When the 1-6 FucT gene was transfected into a human HCC cell line, Hep3B, which originally showed low levels of 1-6 FucT expression, 1-6-fucosylated AFP was dramatically increased in the condition media. Collectively, these results suggest that the enhancement of 1-6 FucT expression increased the fucosylation of several proteins, including AFP, and that the level of 1-6-fucosylated AFP in patients with HCC was in part caused by up-regulation of the 1-6 FucT gene expression.
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Gao C, Mao S, Lo CH, Wirsching P, Lerner RA, Janda KD. Making artificial antibodies: a format for phage display of combinatorial heterodimeric arrays. Proc Natl Acad Sci U S A 1999; 96:6025-30. [PMID: 10339535 PMCID: PMC26829 DOI: 10.1073/pnas.96.11.6025] [Citation(s) in RCA: 111] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/30/1999] [Indexed: 11/18/2022] Open
Abstract
The gene VII protein (pVII) and gene IX protein (pIX) are associated closely on the surface of filamentous bacteriophage that is opposite of the end harboring the widely exploited pIII protein. We developed a phagemid format wherein antibody heavy- and light-chain variable regions were fused to the amino termini of pVII and pIX, respectively. Significantly, the fusion proteins interacted to form a functional Fv-binding domain on the phage surface. Our approach will be applicable to the display of generic peptide and protein libraries that can form combinatorial heterodimeric arrays. Consequently, it represents a first step toward artificial antibodies and the selection of novel biological activities.
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Kobayashi N, Ito M, Nakamura J, Cai J, Gao C, Hammel JM, Fox IJ. Hepatocyte transplantation in rats with decompensated cirrhosis. Hepatology 2000; 31:851-7. [PMID: 10733539 DOI: 10.1053/he.2000.5636] [Citation(s) in RCA: 99] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Hepatocyte transplantation improves the survival of laboratory animals with experimentally induced acute liver failure and the physiological abnormalities associated with liver-based metabolic deficiencies. The role of hepatocyte transplantation in treating decompensated liver cirrhosis, however, has not been studied in depth. To address this issue, cirrhosis was induced using phenobarbital and carbon tetrachloride (CCL(4)) and animals were studied only when evidence of liver failure did not improve when CCL(4) was held for 4 weeks. Animals received intrasplenic transplantation of syngeneic rat hepatocytes (G1); intraperitoneal transplantation of syngeneic rat hepatocytes (G2); intraperitoneal transplantation of a cellular homogenate of syngeneic rat hepatocytes (G3); intraperitoneal transplantation of syngeneic rat bone marrow cells (G4); or intrasplenic injection of Dulbecco's modified Eagle medium (DMEM) (G5). After transplantation, body weight and serum albumin levels deteriorated over time in all control (G2-G5) animals but did not deteriorate in animals receiving intrasplenic hepatocyte transplantation (G1) (P <.01). Prothrombin time (PT), total bilirubin, serum ammonia, and hepatic encephalopathy score were also significantly improved toward normal in animals receiving intrasplenic hepatocyte transplantation (P <. 01). More importantly, survival was prolonged after a single infusion of hepatocytes and a second infusion prolonged survival from 15 to 128 days (P <.01). Thus, hepatocyte transplantation can improve liver function and prolong the survival of rats with irreversible, decompensated cirrhosis and may be useful in the treatment of cirrhosis in humans.
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10
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Heine A, Stura EA, Yli-Kauhaluoma JT, Gao C, Deng Q, Beno BR, Houk KN, Janda KD, Wilson IA. An antibody exo Diels-Alderase inhibitor complex at 1.95 angstrom resolution. Science 1998; 279:1934-40. [PMID: 9506943 DOI: 10.1126/science.279.5358.1934] [Citation(s) in RCA: 98] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
A highly specific Diels-Alder protein catalyst was made by manipulating the antibody repertoire of the immune system. The catalytic antibody 13G5 catalyzes a disfavored exo Diels-Alder transformation in a reaction for which there is no natural enzyme counterpart and that yields a single regioisomer in high enantiomeric excess. The crystal structure of the antibody Fab in complex with a ferrocenyl inhibitor containing the essential haptenic core that elicited 13G5 was determined at 1.95 angstrom resolution. Three key antibody residues appear to be responsible for the observed catalysis and product control. Tyrosine-L36 acts as a Lewis acid activating the dienophile for nucleophilic attack, and asparagine-L91 and aspartic acid-H50 form hydrogen bonds to the carboxylate side chain that substitutes for the carbamate diene substrate. This hydrogen-bonding scheme leads to rate acceleration and also pronounced stereoselectivity. Docking experiments with the four possible ortho transition states of the reaction explain the specific exo effect and suggest that the (3R,4R)-exo stereoisomer is the preferred product.
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Lin Z, Gao N, Hu HZ, Liu S, Gao C, Kim G, Ren J, Xia Y, Peck OC, Wood JD. Immunoreactivity of Hu proteins facilitates identification of myenteric neurones in guinea-pig small intestine. Neurogastroenterol Motil 2002; 14:197-204. [PMID: 11975720 DOI: 10.1046/j.1365-2982.2002.00317.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Hu proteins, together with neurone-specific enolase (NSE), protein gene product 9.5 (PGP-9.5), microtubule-associated protein-2 (MAP-2) and tubulin beta III isoform, were evaluated immunohistochemically as neuronal markers in whole-mount preparations and cultures obtained from the myenteric plexus of guinea-pig small intestine. Anti-Hu immunostaining marked the ganglion cell somas and nuclei without staining of the neuronal processes in the whole-mounts and cultures. The ganglion cell bodies were not obscured by staining of multiple neuronal fibres and this facilitated accurate counting of the neurones. MAP2 immunostaining also provided clear images of individual neurones in both whole mounts and cultures. Immunoreactivity for NSE, PGP-9.5 and tubulin beta III isoform provided sharp images of the ganglion cells in culture, but not in whole-mount preparations. Strong staining of the neuronal processes in the whole-mount preparations obscured the profiles of the ganglion cell bodies to such an extent that accurate counting of the total neuronal population was compromised. Anti-Hu immunostaining was judged to be an acceptable method for obtaining reliable estimates of total numbers of myenteric neurones in relation to other specific histochemical properties such as histamine binding.
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Zhang S, Zhao YG, Li PS, Yang JJ, Rizwan S, Zhang JX, Seidel J, Qu TL, Yang YJ, Luo ZL, He Q, Zou T, Chen QP, Wang JW, Yang LF, Sun Y, Wu YZ, Xiao X, Jin XF, Huang J, Gao C, Han XF, Ramesh R. Electric-field control of nonvolatile magnetization in Co40Fe40B20/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O3 structure at room temperature. PHYSICAL REVIEW LETTERS 2012; 108:137203. [PMID: 22540724 DOI: 10.1103/physrevlett.108.137203] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2011] [Indexed: 05/31/2023]
Abstract
We report a large and nonvolatile bipolar-electric-field-controlled magnetization at room temperature in a Co(40)Fe(40)B(20)/Pb(Mg(1/3)Nb(2/3))(0.7)Ti(0.3)O(3) structure, which exhibits an electric-field-controlled looplike magnetization. Investigations on the ferroelectric domains and crystal structures with in situ electric fields reveal that the effect is related to the combined action of 109° ferroelastic domain switching and the absence of magnetocrystalline anisotropy in Co(40)Fe(40)B(20). This work provides a route to realize large and nonvolatile magnetoelectric coupling at room temperature and is significant for applications.
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Hu HZ, Gao N, Zhu MX, Liu S, Ren J, Gao C, Xia Y, Wood JD. Slow excitatory synaptic transmission mediated by P2Y1 receptors in the guinea-pig enteric nervous system. J Physiol 2003; 550:493-504. [PMID: 12807993 PMCID: PMC2343037 DOI: 10.1113/jphysiol.2003.041731] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Electrophysiological recording was used to study a type of slow excitatory postsynaptic potential (slow EPSP) that was mediated by release of ATP and its action at P2Y1 receptors on morphologically identified neurones in the submucosal plexus of guinea-pig small intestine. MRS2179, a selective P2Y1 purinergic receptor antagonist, blocked both the slow EPSP and mimicry of the EPSP by exogenously applied ATP. Increased conductance accounted for the depolarization phase of the EPSP, which occurred exclusively in neurones with S-type electrophysiological behaviour and uniaxonal morphology. The purinergic excitatory input to the submucosal neurones came from neighbouring neurones in the same plexus, from neurones in the myenteric plexus and from sympathetic postganglionic neurones. ATP-mediated EPSPs occurred coincident with fast nicotinic synaptic potentials evoked by the myenteric projections and with noradrenergic IPSPs evoked by sympathetic fibres that innervated the same neurones. The P2Y1 receptor on the neurones was identified as a metabotropic receptor linked to activation of phospholipase C, synthesis of inositol 1,4,5-trisphosphate and mobilization of Ca2+ from intracellular stores.
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Kunisada T, Miyazaki M, Mihara K, Gao C, Kawai A, Inoue H, Namba M. A new human chondrosarcoma cell line (OUMS-27) that maintains chondrocytic differentiation. Int J Cancer 1998; 77:854-9. [PMID: 9714054 DOI: 10.1002/(sici)1097-0215(19980911)77:6<854::aid-ijc10>3.0.co;2-1] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
A new human chondrosarcoma cell line, OUMS-27, was established. Monolayer cultures consisted of elongated polygonal cells with a doubling time of 41 hr and a plating efficiency of 2.1%. After reaching confluence, the cells continued to slowly proliferate and formed nodule-like structures, which showed metachromasia when stained with toluidine blue, indicating the presence of proteoglycan. The cells in the nodules were round to polygonal in shape, multilayered and surrounded by abundant extracellular matrix. Types I, II and III collagens were identified by Northern blotting and immunostaining. The cells formed colonies (0.1%) in 0.3% soft-agar medium 3 weeks after inoculation. Inoculation of cells into athymic mice resulted in the formation of tumors at the injection site, resembling the original chondrosarcoma. These results demonstrated that OUMS-27 cells expressed a differentiated chondrocytic phenotype. Moreover, OUMS-27 cells had p53-gene mutation. Thus, the OUMS-27 cell line can provide a useful model not only for studies on human chondrocyte but also for basic studies on the diagnosis, treatment and etiology of human chondrosarcoma.
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Ahmed W, Zhai Z, Gao C. Adaptive antibacterial biomaterial surfaces and their applications. Mater Today Bio 2019; 2:100017. [PMID: 32159147 PMCID: PMC7061676 DOI: 10.1016/j.mtbio.2019.100017] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2019] [Revised: 06/14/2019] [Accepted: 06/18/2019] [Indexed: 12/20/2022] Open
Abstract
Bacterial infections on the implant surface may eventually lead to biofilm formation and thus threaten the use of implants in body. Despite efficient host immune system, the implant surface can be rapidly occupied by bacteria, resulting in infection persistence, implant failure, and even death of the patients. It is difficult to cope with these problems because bacteria exhibit complex adhesion mechanisms to the implants that vary according to bacterial strains. Different biomaterial coatings have been produced to release antibiotics to kill bacteria. However, antibiotic resistance occurs very frequently. Stimuli-responsive biomaterials have gained much attention in recent years but are not effective enough in killing the pathogens because of the complex mechanisms in bacteria. This review is focused on the development of highly efficient and specifically targeted biomaterials that release the antimicrobial agents or respond to bacteria on demands in body. The mechanisms of bacterial adhesion, biofilm formation, and antibiotic resistance are discussed, and the released substances accounting for implant infection are described. Strategies that have been used in past for the eradication of bacterial infections are also discussed. Different types of stimuli can be triggered only upon the existence of bacteria, leading to the release of antibacterial molecules that in turn kill the bacteria. In particular, the toxin-triggered, pH-responsive, and dual stimulus-responsive adaptive antibacterial biomaterials are introduced. Finally, the state of the art in fabrication of dual responsive antibacterial biomaterials and tissue integration in medical implants is discussed.
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Review |
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Mao S, Gao C, Lo CH, Wirsching P, Wong CH, Janda KD. Phage-display library selection of high-affinity human single-chain antibodies to tumor-associated carbohydrate antigens sialyl Lewisx and Lewisx. Proc Natl Acad Sci U S A 1999; 96:6953-8. [PMID: 10359820 PMCID: PMC22023 DOI: 10.1073/pnas.96.12.6953] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
mAbs against tumor-associated carbohydrate antigens have the potential to play a prominent role in cancer immunotherapy. However, it has not been possible to fully exploit the clinical utility of such antibodies primarily, because those of adequate affinity could be derived only from murine sources. To address this problem, we prepared a single-chain Fv (scFv) antibody library from the peripheral blood lymphocytes of 20 patients with various cancer diseases. Completely human high-affinity scFv antibodies were then selected by using synthetic sialyl Lewisx and Lewisx BSA conjugates. These human scFv antibodies were specific for sialyl Lewisx and Lewisx, as demonstrated by ELISA, BIAcore, and flow cytometry binding to the cell surface of pancreatic adenocarcinoma cells. Nucleotide sequencing revealed that at least four unique scFv genes were obtained. The Kd values ranged from 1.1 to 6.2 x 10(-7) M that were comparable to the affinities of mAbs derived from the secondary immune response. These antibodies could be valuable reagents for probing the structure and function of carbohydrate antigens and in the treatment of human tumor diseases.
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Fan LL, Chen S, Luo ZL, Liu QH, Wu YF, Song L, Ji DX, Wang P, Chu WS, Gao C, Zou CW, Wu ZY. Strain dynamics of ultrathin VO₂ film grown on TiO₂ (001) and the associated phase transition modulation. NANO LETTERS 2014; 14:4036-4043. [PMID: 24956434 DOI: 10.1021/nl501480f] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Tuning the metal insulator transition (MIT) behavior of VO2 film through the interfacial strain is effective for practical applications. However, the mechanism for strain-modulated MIT is still under debate. Here we directly record the strain dynamics of ultrathin VO2 film on TiO2 substrate and reveal the intrinsic modulation process by means of synchrotron radiation and first-principles calculations. It is observed that the MIT process of the obtained VO2 films can be modulated continuously via the interfacial strain. The relationship between the phase transition temperature and the strain evolution is established from the initial film growth. From the interfacial strain dynamics and theoretical calculations, we claim that the electronic orbital occupancy is strongly affected by the interfacial strain, which changes also the electron-electron correlation and controls the phase transition temperature. These findings open the possibility of an active tuning of phase transition for the thin VO2 film through the interfacial lattice engineering.
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Hu HZ, Gao N, Lin Z, Gao C, Liu S, Ren J, Xia Y, Wood JD. P2X(7) receptors in the enteric nervous system of guinea-pig small intestine. J Comp Neurol 2001; 440:299-310. [PMID: 11745625 DOI: 10.1002/cne.1387] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The P2X(7) purinergic receptor subtype has been cloned and emphasized as a prototypic P2Z receptor involved in neurotransmission in the central nervous system and ATP-mediated lysis of macrophages in the immune system. Less is known about the neurobiology of P2X(7) receptors in the enteric nervous system (ENS). We studied the distribution of the receptor with indirect immunofluorescence and used selective agonists and antagonists to analyze pharmacologic aspects of its electrophysiologic behavior as determined with intracellular "sharp" microelectrodes and patch-clamp recording methods in neurons identified morphologically by biocytin injection in the ENS. Application of ATP or 2'- (or-3'-) O-(4-benzoylbenzoyl) adenosine 5'-triphosphate (BzBzATP) activated an inward current in myenteric neurons. Brilliant blue G, a selective P2X(7) antagonist, suppressed the responses to both agonists. Potency of the antagonist was greatest (smaller IC(50)) for the current evoked by BzBzATP. The P2X(7) antagonists 1-[N,O-bis (1,5-isoquinolinesulfonyl)-N-methyl-l-tyrosyl]-4-piperazine (KN-62) and oxidized ATP also suppressed the BzBzATP-activated current. Micropressure application of BzBzATP evoked rapidly activating depolarizing responses in intracellular studies with "sharp" microelectrodes. Oxidized-ATP suppressed these responses in both myenteric and submucosal neurons. Rapidly activating depolarizing responses evoked by application of nicotinic, serotonergic 5-HT(3), or gamma-aminobutyric acid A (GABA(A)) receptor agonists were unaffected by brilliant blue G. Immunoreactivity for the P2X(7) receptor was widely distributed surrounding ganglion cell bodies and associated with nerve fibers in both myenteric and submucous plexuses. P2X(7) immunoreactivity was colocalized with synapsin and synaptophysin and surrounded ganglion cells that contained either calbindin, calretinin, neuropeptide Y, substance P, or nitric oxide synthase. The mucosa, submucosal blood vessels, and the circular muscle coat also showed P2X(7) receptor immunoreactivity.
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Liu Y, Zhang G, Gao C, Hou X. NMDA receptor activation results in tyrosine phosphorylation of NMDA receptor subunit 2A(NR2A) and interaction of Pyk2 and Src with NR2A after transient cerebral ischemia and reperfusion. Brain Res 2001; 909:51-8. [PMID: 11478920 DOI: 10.1016/s0006-8993(01)02619-1] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Transient ischemia increases tyrosine phosphorylation of N-methyl-D-aspartate (NMDA) receptor. Several tyrosine kinases are involved in this process. In this study, effect of ischemia and reperfusion (I/R) on tyrosine phosphorylation of NMDA receptor subunit 2A (NR2A) and the interaction of two tyrosine kinases, Src and Pyk2, with NR2A was investigated. Four-vessel occlusion was used to produce transient (15 min) cerebral ischemia in SD rats. Tyrosine phosphorylation of NR2A in hippocampus was enhanced after 15 min of reperfusion and reached its peak level at 6 h of reperfusion. The increase sustained for at least 24 h. Src and Pyk2 co-immunoprecipitated with NR2A and the binding increased after I/R, which also reached a peak at 6 h of reperfusion. Besides, Src and Pyk2 were activated after I/R. These increases were prevented by ketamine, a selective NMDA receptor antagonist, which was administered to the SD rats 20 min before ischemia. Moreover, Src and Pyk2 coprecipitated with each other. These data show that NR2A, Src and Pyk2 might form a protein complex in vivo and the interaction suggests a possible mechanism of signal transduction in the postischemic hippocampus.
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Juan D, Zhou DHD, Li J, Wang JYJ, Gao C, Chen M. A 2-year follow-up study of cigarette smoking and risk of dementia. Eur J Neurol 2004; 11:277-82. [PMID: 15061830 DOI: 10.1046/j.1468-1331.2003.00779.x] [Citation(s) in RCA: 68] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The report focused on investigating the relationship between cigarette smoking and dementia in elderly people through prospective studies. We did a 2-year follow-up study of elderly people. A total of 2820 participants aged 60 years old and over from six communities of Chongqing agreed to take part. Dementia was diagnosed with MMSE (Mini-Mental State Examination) and DSM-III-R (Diagnostic and Statistical Manual of Mental Disorders). Participants were classified as never smokers, past smokers, and current smokers. During follow-up, we recorded incident cases of dementia. The association of smoking and dementia was investigated using proportional hazards regression analysis. A total of 121 incident cases of dementia were detected, of which 84 (69%) were Alzheimer's disease, 17 (14%) were vascular dementia, and 21(17%) were other dementia. Compared with never smokers, current smokers had an increased risk of Alzheimer's disease (RR = 2.72; 95% CI = 1.63-5.42) and vascular dementia (RR = 1.98; 95% CI = 1.53-3.12) adjusting for age, sex, education, blood pressure, and alcohol intake. Compared with light smokers, the adjusted risk of Alzheimer's disease was significantly increased among smokers with a medium level of exposure (RR = 2.56; 95% CI = 1.65-5.52), with an even higher risk of Alzheimer's disease in the heavy smoking group (RR = 3.03; 95% CI = 1.25-4.02). Smoking was associated with the risk of dementia. This study suggests that both smoking status and amount is associated with dementia.
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Research Support, Non-U.S. Gov't |
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68 |
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Gao C, Mayon P, MacManus DA, Vulfson EN. Novel enzymatic approach to the synthesis of flavonoid glycosides and their esters. Biotechnol Bioeng 2001; 71:235-43. [PMID: 11291033 DOI: 10.1002/1097-0290(2000)71:3<235::aid-bit1013>3.0.co;2-m] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Flavonoids such as (+)catechin can be efficiently solubilised in supersaturated solutions prepared with donor glycosides, e.g., p-nitrophenyl glycosides, di- and higher oligosaccharides, and poly(ethylene glycol) dimethyl ether in sufficiently high concentration for their efficient enzymatic glycosylation. Under these conditions several glycosidases readily accept (+)catechin as substrate and the target glycosides were prepared in one step in up to 26% yields. The regioselectivity of the reaction depends on the enzyme and substrate combination used; three positions, 5, 7, and 4', in the flavonoid can be glycosylated. The resulting and similar flavonoid glycosides were further modified by regioselective acylation with vinyl esters of arylpropenoic acids using lipases as biocatalyst. The efficiency of acylation was found to diminish in the order of vinyl cinnamate > vinyl ferulate > vinyl coumarate. This work demonstrates the feasibility of assembling complex flavonoid glycoside esters in just two steps by sequential use of commercially available glycosidases and lipases.
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Gao C, Zhang Z, Liu W, Xiao S, Gu W, Lu H. Reduced microRNA-218 expression is associated with high nuclear factor kappa B activation in gastric cancer. Cancer 2010; 116:41-9. [PMID: 19890957 DOI: 10.1002/cncr.24743] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
BACKGROUND Poor expression of microRNAs (miRs) reportedly plays an important role in gastric carcinogenesis. Large-scale microarray assays have indicated that there is significant down-regulation of miR-218 in gastric cancer. miR-218 also was decreased specifically in human papillomavirus-positive cell lines, cervical lesions, and cervical cancer tissues and in bronchial airway epithelium in smokers. However, its role in carcinogenesis remains unclear, especially in Helicobacter pylori (H. pylori)-associated gastric cancer. METHODS miR-218 levels were evaluated in 20 noncardia gastric cancer tissues, in 10 H. pylori-infected and 8 uninfected normal gastric biopsies, and in the human gastric epithelial cancer cell line AGS using TaqMan quantitative real-time polymerase chain reaction analysis. Pre-miR-218 and anti-miR-218 inhibitors were used to examine the effects of miR-218 expression on cell proliferation and apoptosis. A luciferase reporter assay was used to examine the potential target genes and related pathways. RESULTS miR-218 expression was reduced significantly in gastric cancer tissues, in H. pylori-infected gastric mucosa, and in H. pylori-infected AGS cells. Overexpression of miR-218 inhibited cell proliferation and increased apoptosis in vitro. Epidermal growth factor receptor-coamplified and overexpressed protein (ECOP), which regulates nuclear factor kappa B (NF-kappaB) transcriptional activity and is associated with apoptotic response, was a direct target of miR-218. Overexpression of miR-218 also inhibited NF-kappaB transcriptional activation and transcription of cyclooxygenase -2, a proliferative gene regulated by NF-kappaB. CONCLUSIONS H. pylori infection resulted in a decrease in miR-218 expression. The down-regulation of miR-218 has the potential to increase carcinogenesis by losing control of its targets, and it may be correlated with the high transcriptional activity of NF-kappaB that results from H. pylori infection.
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Research Support, Non-U.S. Gov't |
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Gao C, Xie R, Yu C, Wang Q, Shi F, Yao C, Xie R, Zhou J, Gilbert GE, Shi J. Procoagulant activity of erythrocytes and platelets through phosphatidylserine exposure and microparticles release in patients with nephrotic syndrome. Thromb Haemost 2012; 107:681-9. [PMID: 22370875 DOI: 10.1160/th11-09-0673] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 01/09/2012] [Indexed: 12/30/2022]
Abstract
Recent studies showed that an imbalance of prothrombotic and antithrombotic factors and impaired thrombolytic activity contribute to the thrombophilia of the nephrotic syndrome (NS). However, it is not clear whether blood cell injury and/or activation is involved in hypercoagulability in NS patients. Our objectives were to study the increase in microparticle (MP) release and phosphatidylserine (PS) exposure on the outer membrane of MP-origin cells in NS patients, and to evaluate their procoagulant activity (PCA). The subjects were patients with membranous nephropathy (MN), minimal change nephrotic syndrome (MCNS) and healthy controls. Analyses of MPs and PS exposure were performed using a flow cytometer. PCA was determined by clotting time and purified coagulation complex assays. We found that lactadherin+ MPs, which derived from red blood cells (RBC), platelet and endothelial cell, increased in NS patients. Moreover, PS exposure on RBCs and platelets in each NS group, especially in MN, are higher than that in controls. MP shedding and PS exposure of RBCs/platelets were highly procoagulant in NS patients. However, blockade of PS with lactadherin inhibited over 90% of PCA while an anti-tissue factor antibody had no significant inhibition effect. Our results demonstrate that the thrombophilic susceptibility of NS may be partly ascribed to MP release and PS exposure of RBCs, platelets and endothelial cells. Lactadherin is a sensitive probe for PS that has high anticoagulant activity.
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Journal Article |
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Lacourt M, Gao C, Li A, Girard C, Beauchamp G, Henderson JE, Laverty S. Relationship between cartilage and subchondral bone lesions in repetitive impact trauma-induced equine osteoarthritis. Osteoarthritis Cartilage 2012; 20:572-83. [PMID: 22343573 DOI: 10.1016/j.joca.2012.02.004] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2011] [Revised: 12/22/2011] [Accepted: 02/09/2012] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To correlate degenerative changes in cartilage and subchondral bone in the third carpal bone (C3) of Standardbred racehorses with naturally occurring repetitive trauma-induced osteoarthritis. DESIGN Fifteen C3, collected from Standardbred horses postmortem, were assessed for cartilage lesions by visual inspection and divided into Control (CO), Early Osteoarthritis (EOA) and Advanced Osteoarthritis (AOA) groups. Two osteochondral cores were harvested from corresponding dorsal sites on each bone and scanned with a micro-computed tomography (CT) instrument. 2D images were assembled into 3D reconstructions that were used to quantify architectural parameters from selected regions of interest, including bone mineral density and bone volume fraction. 2D images, illustrating the most severe lesion per core, were scored for architectural appearance by blinded observers. Thin sections of paraffin-embedded decalcified cores stained with Safranin O-Fast Green, matched to the micro-CT images, were scored using a modified Mankin scoring system. RESULTS Subchondral bone pits with deep focal areas of porosity were seen more frequently in AOA than EOA but never in CO. Articular cartilage damage was seen in association with a reduction in bone mineral and loss of bone tissue. Histological analyses revealed significant numbers of microcracks in the calcified cartilage of EOA and AOA groups and a progressive increase in the score compared with CO bones. CONCLUSION The data reveal corresponding, progressive degenerative changes in articular cartilage and subchondral bone, including striking focal resorptive lesions, in the third carpal bone of racehorses subjected to repetitive, high impact trauma.
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Li X, Gao C, Yang Y, Zhou F, Li M, Jin Q, Gao L. Systematic review with meta-analysis: the association between human papillomavirus infection and oesophageal cancer. Aliment Pharmacol Ther 2014; 39:270-81. [PMID: 24308856 DOI: 10.1111/apt.12574] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2013] [Revised: 04/05/2013] [Accepted: 11/13/2013] [Indexed: 12/18/2022]
Abstract
BACKGROUND Human papillomavirus (HPV) infection might be one of the potential risk factors for oesophageal cancer. However, the previous epidemiological findings were heterogeneous. AIM To explore the association between HPV infection and oesophageal cancer risk by means of meta-analysis. METHODS Studies on HPV infection and oesophageal cancer were identified, the prevalence of HPV infection and its association with oesophageal cancer risk were quantitatively summarised by meta-analysis. RESULTS A total of 8990 oesophageal squamous cell carcinoma (SCC) patients and 174 oesophageal adenocarcinomas patients were evaluated from 76 included studies. Summarised HPV prevalence in oesophageal SCC was 22.2% [95% confidence interval (CI), 18.3-26.7%], HPV-16 was the most frequently observed subtype with a summarised prevalence of 11.4% (95% CI: 8.2-15.7%). With respect to oesophageal adenocarcinoma, HPV prevalence was 35.0% (95% CI, 13.2-65.7%) and HPV-16 prevalence was 11.4% (95% CI: 8.2-15.7%). Due to the limited number of included studies on oesophageal adenocarcinoma, association analyses were performed to oesophageal SCC only. Significant association was observed between HPV infection and oesophageal SCC with a summarised odds ratio of 3.32 (95% CI, 2.26-4.87). According to HPV-16, the strength of the association was found to be 3.52 (95% CI, 2.04-6.07). CONCLUSIONS Human papillomavirus infection was observed to be associated with an increased risk of oesophageal SCC in this meta-analysis. However, due to the evident heterogeneity observed between the included studies and the strength of the association not as strong as observed for cervical cancer and laryngeal cancer, further studies are needed to clarify the relation and its underlying mechanisms.
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Meta-Analysis |
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