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Yan G, Dai Z, Shen Z, Wu R. Behavioral and neurochemical alterations in C57BL/6 mice exposed to cuprizone: An in vivo 1H-MRS STUDY at 7.0T. J Neurol Sci 2013. [DOI: 10.1016/j.jns.2013.07.2186] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Yi M, Yan G, Xuan Y, Dai Z, Li S, Wu R. Study on euronal metabolic characterization in peritumoral area of C6 rat glioma using 1h MRS at 7T. J Neurol Sci 2013. [DOI: 10.1016/j.jns.2013.07.2168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Dai Z, Wang R, Ang LW, Yuan JM, Koh WP. Dietary B vitamin intake and risk of hip fracture: the Singapore Chinese Health Study. Osteoporos Int 2013; 24:2049-59. [PMID: 23238962 PMCID: PMC9254692 DOI: 10.1007/s00198-012-2233-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2012] [Accepted: 11/26/2012] [Indexed: 12/31/2022]
Abstract
UNLABELLED This prospective cohort study that comprehensively examined effects of different B vitamins in an Asian population showed an inverse relationship between dietary intake of pyridoxine and hip fracture risk in elderly women. These findings suggest that maintaining sufficient pyridoxine intake may be beneficial in preserving bone health in postmenopausal women. INTRODUCTION B vitamins have recently been investigated for their possible roles in maintaining bone health. Incidence of osteoporotic hip fracture has been rising in Asia, but epidemiological data on dietary B vitamins and risk of osteoporotic fractures are sparse. We aimed to examine the association between dietary intakes of B vitamins (thiamin, riboflavin, niacin, pyridoxine, folate, and cobalamin) and hip fracture risk among elderly Chinese in Singapore. METHODS The current study was conducted in the Singapore Chinese Health Study, which is a population-based cohort prospective study that enrolled a total of 63,257 men and women aged 45-74 years between 1993 and 1998. Dietary intakes of B vitamins were derived from a validated food frequency questionnaire and the Singapore Food Composition Database. RESULTS After a mean follow-up period of 13.8 years, 1,630 hip fracture incident cases were identified. A statistically significant inverse relationship between dietary pyridoxine intake and hip fracture risk was observed among women (p for trend = 0.002) but not among men. Compared to women in the lowest quartile intake (0.37-0.61 mg/1,000 kcal/day), women in the highest quartile intake (0.78-1.76 mg/1,000 kcal/day) had a 22 % reduction in hip fracture risk (hazard ratio 0.78, 95 % confidence interval 0.66-0.93). Dietary intakes of the other B vitamins of interest were not related to hip fracture risk. CONCLUSIONS Our findings suggest that maintaining adequate intake of pyridoxine may prevent osteoporotic fractures among elderly women.
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Wu C, Zhang H, Qian Y, Wang L, Gu X, Dai Z. Hypophosphatemic osteomalacia and renal Fanconi syndrome induced by low-dose adefovir dipivoxil: a case report and literature review suggesting ethnic predisposition. J Clin Pharm Ther 2013; 38:321-6. [PMID: 23590583 DOI: 10.1111/jcpt.12050] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2012] [Accepted: 01/28/2013] [Indexed: 01/18/2023]
Abstract
WHAT IS KNOWN AND OBJECTIVE Adefovir dipivoxil (ADV) is one of the commonly used antiviral agents in the treatment of chronic hepatitis B (CHB) infection. Safety of a daily dose of 10 mg ADV is advocated by the registration trials. We report a case of severe hypophosphatemic osteomalacia and renal Fanconi syndrome induced by low-dose ADV in a CHB-related cirrhosis patient, and discuss the case through a thorough review of other cases reported in the literature. CASE SUMMARY A 48-yr-old Chinese man with CHB-related cirrhosis developed severe progressive generalized bone pain and muscle weakness after receiving ADV 10 mg daily for 54 months. The laboratory results showed severe hypophosphatemia and features of proximal renal tubule dysfunction. Imaging studies were consistent with osteomalacia. After discontinuation of ADV, his symptoms resolved, laboratory abnormalities normalized and imaging studies showed improvement. In addition to our case, 12 other patients have been reported to have developed hypophosphatemic osteomalacia induced by low-dose ADV. Most of the reported cases were of subjects of East-Asian ethnicity. After discontinuation or reduction of ADV, serum phosphate level increased and clinical symptoms significantly improved in all cases. WHAT IS NEW AND CONCLUSION Hypophosphatemic osteomalacia and renal Fanconi syndrome can be associated with low-dose ADV. Clinicians treating CHB patients with ADV 10 mg daily over long periods of time should be aware of this infrequent but serious complication.
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Xiao J, Li HB, Zhou WQ, Luo NQ, Liang Y, Shao JM, Liu P, Zou XY, Dai Z, Yang GW. A new insight into the electrochemical growth of Ag nanodendrites without a strong electrolyte. RSC Adv 2013. [DOI: 10.1039/c3ra44097d] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
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Xue J, Zhao H, Shang G, Zou R, Dai Z, Zhou D, Huang Q, Xu Y. RIP140 is associated with subclinical inflammation in type 2 diabetic patients. Exp Clin Endocrinol Diabetes 2012; 121:37-42. [PMID: 22956256 DOI: 10.1055/s-0032-1323683] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
AIMS To evaluate the expression level of RIP140 (receptor interaction protein 140) and its correlation with inflammatory cytokine production and free fatty acids (FFAs) in type 2 diabetes. METHODS Plasma and peripheral blood mononuclear cells (PBMCs) were collected from 24 diabetic and 30 healthy individuals. The levels of FFAs, TC, TG, HDL-C, LDL-C, FIN, and FBG were measured. The insulin resistance index was calculated using the homeostasis model assessment (HOMA). Additionally, PBMCs from control group were cultured alone or with 500 μmol/L palmitic acid (PA). Levels of RIP140 TNF-α, and IL-6 in PBMCs were analyzed using real-time RT-PCR, Western blots and ELISA. The relationship between RIP140 and other variables was performed using SPSS 11.5 software. RESULTS TG, LDL-C, FIN, FBG, HOMA, and HDL-C were significantly different between diabetic patients and the control group. Levels of RIP140, TNF-α, and IL-6 were higher in the diabetic group compared to control. RIP140 expression was positively correlated with FFAs, HDL-c, TNF-α, IL-6, FIN, FBG, and HOMA. Finally, 500 μmol/L PA treatment increased RIP140 expression and the secretion of inflammatory cytokines in cultured control PBMCs. CONCLUSIONS Increased RIP140 level may be closely associated with inflammation and disorder of lipid and glucose metabolism in diabetic patients.
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Wan F, Dai H, Zhang S, Moore Y, Wan N, Dai Z. Cigarette smoke exposure hinders long-term allograft survival by suppressing indoleamine 2, 3-dioxygenase expression. Am J Transplant 2012; 12:610-9. [PMID: 22050701 DOI: 10.1111/j.1600-6143.2011.03820.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Cigarette smoke causes cancer and increases the vulnerability of smokers to infections. Epidemiologic studies have shown that smoking is one of major risk factors for late allograft rejection. Despite statistical data that associate smoking with allograft rejection, no any study has been conducted to prove that cigarette smoke directly causes allograft rejection in a cause-effect manner. In particular, investigation into immunologic mechanisms underlying smoke-related allograft rejection is lacking. Here we found that second hand smoke (SHS) hindered long-term islet allograft survival induced by CD154 costimulatory blockade plus donor-specific splenocyte transfusion (DST), although it failed to alter acute islet allograft rejection. SHS did not directly interfere with vigorously alloreactive T-cell proliferation in vivo and in vitro. Neither naturally occurring nor induced CD4+CD25+ Treg cell numbers were significantly reduced by SHS. However, SHS suppressed mRNA and protein expression of indoleamine 2, 3-dioxygenase (IDO) and its activity upon transplantation while IDO overexpression in islet allografts restored their long-term survival induced by CD154 blockade. Therefore, SHS prevents long-term allograft survival by inhibiting IDO expression and activity. Thus, our study for the first time demonstrates that SHS shortens allograft survival in a cause-effect manner and unveils a novel immunologic mechanism underlying smoking-related allograft rejection.
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Zhou S, Tan C, Dai Z, Zhu H, Xu M, Zhou Z, Wang W, Zhao Y, Fu X, Zhou J, Fan J. Tacrolimus enhances the invasion potential of hepatocellular carcinoma cells and promotes lymphatic metastasis in a rat model of hepatocellular carcinoma: involvement of vascular endothelial growth factor-C. Transplant Proc 2012; 43:2747-54. [PMID: 21911157 DOI: 10.1016/j.transproceed.2011.06.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 05/20/2011] [Accepted: 06/13/2011] [Indexed: 01/06/2023]
Abstract
PURPOSE The purpose of this study was to elucidate the effect of tacrolimus treatment on tumor growth and metastasis of hepatocellular carcinoma (HCC). METHODS The effect of tacrolimus was investigated on tumor growth and lymph node metastasis in a rat model of HCC. Angiogenesis and lymphangiogenesis were assessed by CD31 and vascular endothelial growth factor receptor 3 (VEGFR-3) immunostaining. Cell proliferation and invasion were monitored in vitro using the Cell Counting Kit-8 (CCK8) and Matrigel Invasion Chambers, respectively. Levels of vascular endothelial growth factor-C (VEGF-C) expression were measured using quantitative real-time polymerase chain reaction (qRT-PCR), immunohistochemisty and Western blots. RESULTS Tacrolimus had no effect on the proliferation of HCC in vitro or in vivo. Treatment with tacrolimus resulted in a dose-dependent increase in the invasive potential of HCC cells in vitro, in the density of peritumoral lymphatic vessels, and in the number and volume of metastatic lymph nodes in August Copenhagen Irish (ACI) rats. qRT-PCR, immunohistochemisty, and Western blot revealed that tacrolimus increased the levels of expression of VEGF-C in HCC. CONCLUSIONS Tacrolimus enhanced the invasive potential of HCC cells, facilitating HCC lymphangiogenesis and promoting lymphatic metastasis in a rat model of HCC. This influence may be the result of an increase in VEGF-C expression by HCC cells. Targeting the VEGF-C/Fms-related tyrosine kinase 4 axis may be a novel treatment for HCC patients after liver transplantation.
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Li C, Guan F, Dai Z, Jiang H, Wen F, Lu L, Wang Z. [Preparation and characterization of follwing the national standard anti-Brucella abortus serum, bovine]. SHENG WU GONG CHENG XUE BAO = CHINESE JOURNAL OF BIOTECHNOLOGY 2011; 27:812-816. [PMID: 21845849] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
To prepare anti-Brucella abortus serum used for calibrate the agglutination test follwing the national standard, 4 anti-Brucella abortus sera were obtained from 4 cows infected with Brucella abortus naturally. By potency testing, the third serum was selected. Sterility, vaccum degree, residual moisture, uniformity and stability of this standard material were tested and proved to meet the national standard. Referring to the international standard, RBT (Rose-Bengal plate agglutination test), SAT (standard tube agglutination) and CFT (complement fixation test) titers of this standard material were measured to be 1:160 "+" 1:2 400 "++" and 1:800 "++", which are identical with the collaborative assay results. International unit of the standard material is 4 000 IU/mL.
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Wei Z, Wang D, Kim S, Kim SY, Hu Y, Yakes MK, Laracuente AR, Dai Z, Marder SR, Berger C, King WP, de Heer WA, Sheehan PE, Riedo E. Nanoscale Tunable Reduction of Graphene Oxide for Graphene Electronics. Science 2010; 328:1373-6. [DOI: 10.1126/science.1188119] [Citation(s) in RCA: 601] [Impact Index Per Article: 42.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
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Dai Z, King WP, Park K. A 100 nanometer scale resistive heater-thermometer on a silicon cantilever. NANOTECHNOLOGY 2009; 20:095301. [PMID: 19417484 DOI: 10.1088/0957-4484/20/9/095301] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
This paper reports a method for fabricating a 100 nm scale heater-thermometer into a silicon microcantilever based on contact photolithography and a controlled annealing process. The heater is formed during a photolithography process that can achieve a minimum feature size of about 1 microm, while careful control of doping and annealing parameters allows the heater size to be further decreased, to a width of 100 nm. The heater is fabricated onto the free end of a silicon cantilever suitable for scanning probe microscopy, and can be integrated into cantilevers with or without sharp tips. The fabricated heater has a maximum temperature of over 700 degrees C, and a heating time of 56 micros to reach 500 degrees C.
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Li C, Sun X, Gilmore WC, Cobos E, Tao Y, Dai Z. Knockdown of Abl interactor 1 expression impairs invadopodia formation, tumor angiogenesis, and markedly slows tumor growth of breast cancer cells. Cancer Res 2009. [DOI: 10.1158/0008-5472.sabcs-2054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Abstract
Abstract #2054
Background: Abl interactor 1 (Abi1) is a key regulator of actin polymerization/depolymerization. Previous studies have revealed that Abi1 interacts with Wiskott–Aldrich syndrome protein (Wasp) family proteins, and regulates the nucleation promoting activity of Wasp proteins. In addition to Wasp family proteins, Abi1 also binds to a variety of other signaling molecules, including those involved in the signal transductions of small GTP-binding protein Rac and PI3 kinase. The ability to interact with diverse signaling pathways places Abi1 at a central position in the signaling network that regulates cell motility and proliferation. The involvement of Abi1 in the development of abnormal cytoskeletal functions of cancer cells has recently been reported. It remains unclear, however, how Abi1 exerts its effects in tumor cells and whether it contributes to tumor progression in vivo.
 Material and Methods: The short hairpin RNA (shRNA)-mediated gene silencing was used, in conjunction with murine tumor xenograft models, to examine the effects of Abi1 knockdown on cytoskeleton remodeling, cell migration, invasion, as well as tumor growth and angiogenesis of MDA-MB231 breast cancer cells.
 Results: We report here a novel function for Abi1 in the regulation of invadopodia formation as well as in the tumor angiogenesis and invasion of breast cancer cells, possibly through the modulation of Src and matrix metalloproteinase 9 (MMP-9) activities. Abi1 co-localizes with invadopodia, the specialized adhesive/invasive structures believed to control the invasion of tumor cells, in MDA-MB231 breast cancer cells. Epigenetic silencing of the Abi1 gene by shRNA in MDA-MB231 cells impaired the formation of invadopodia and decreased the activity of c-Src and MMP-9. The decreased invadopodia formation and MMP-9 activity correlated with a reduction in the ability of these cells to degrade extracellular matrix (ECM). Remarkably, the knockdown of Abi1 expression inhibited tumor invasion and angiogenesis and markedly slowed tumor growth in xenograft mouse models. Taken together, these results indicate that the Abi1 signaling plays a critical role in breast cancer progression and suggest that this pathway may serve as a therapeutic target for the treatment of human breast cancer.
Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 2054.
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Dai Z, Li P, Sun XX, Zhang JM, Xu SC, Guo N, Wang X. Preparation of fluorescent DNA probe by solid-phase organic synthesis. EXPRESS POLYM LETT 2009. [DOI: 10.3144/expresspolymlett.2009.60] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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114
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Li A, Zhang Y, Wu X, Tang W, Wu R, Dai Z, Liu G, Zhang H, Wu C, Chen G, Pan X. DH1, a LOB domain-like protein required for glume formation in rice. PLANT MOLECULAR BIOLOGY 2008; 66:491-502. [PMID: 18180880 DOI: 10.1007/s11103-007-9283-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/16/2007] [Accepted: 12/22/2007] [Indexed: 05/14/2023]
Abstract
T-DNA tagging is a high throughput strategy for identifying and cloning functional genes in plants. In this study, we screened 4416 lab-created T(1) rice T-DNA tagged lines and identified a mutant, designated dh1 (degenerated hull1), with phenotype of degenerated hull and naked pistils and stamens. Approximately 60% florets on the dh1 panicle defected in forming normal palea and lemma. Instead, they formed degenerative velum-like or filamentous organs accompanying with the lack of lodicules, stamens and pistils at different degree. A 361 bp of genomic sequence flanking the T-DNA isolated using TAIL-PCR (Thermal asymmetric interlaced PCR) co-segregated with the mutation phenotype. Results of blastn and gene prediction revealed the T-DNA inserted into the promoter region of a function-predicted gene at 283 bp upstream of its transcription start site (TSS). The predicted gene encoded a LOB (Lateral Organ Boundaries) domain-like protein. RT-PCR analyses indicated the transcription level of target candidate gene, DH1, decreased significantly in dh1 mutant. RNAi aimed at DH1 in wild type plants could partially result in the mutation phenotype of dh1. DH1 could also rescue the mutation phenotype in the complement experiment. The result of transformation by a fused expression vector, pDH1::GFP, revealed that DH1 had the keen spatial and temporal characteristics of expressing at axillary bud, young panicle and floral organs but not at root, leaf, node and culm, and strongly expressing at young tissues but weakly at mature organs. The dh1 presented severer mutation phenotype under relatively longer daylight than under shorter daylight implied that shorter daylight induced the expression of gene(s) redundant to DH1 in function and partially compensated for the loss-of-function. It is the first time to report the LOB-domain gene participating in the development of floral organs in rice.
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Dai Z, Li Y, Quarles LD, Song T, Pan W, Zhou H, Xiao Z. Resveratrol enhances proliferation and osteoblastic differentiation in human mesenchymal stem cells via ER-dependent ERK1/2 activation. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2007; 14:806-14. [PMID: 17689939 DOI: 10.1016/j.phymed.2007.04.003] [Citation(s) in RCA: 172] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
In the present study, we investigated the in vitro effect of resveratrol (RSVL), a polyphenolic phytoestrogen, on cell proliferation and osteoblastic maturation in human bone marrow-derived mesenchymal stem cell (HBMSC) cultures. RSVL (10(-8)-10(-5) M) increased cell growth dose-dependently, as measured by [(3)H]-thymidine incorporation, and stimulated osteoblastic maturation as assessed by alkaline phosphatase (ALP) activity, calcium deposition into the extracellular matrix, and the expression of osteoblastic markers such as RUNX2/CBFA1, Osterix and Osteocalcin in HBMSCs cell cultures. Further studies found that RSVL (10(-6)M) resulted in a rapid activation of both extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 mitogen-activated protein kinase (MAPK) signaling in HBMSCs cultures. The effects of RSVL were mimicked by 17beta-estrodial (10(-8) M) and were abolished by estrogen receptor (ER) antagonist ICI182780. An ERK1/2 pathway inhibitor, PD98059, significantly attenuated RSVL-induced ERK1/2 phosphorylation, consistent with the reduction of cell proliferation and osteoblastic differentiation as well as expression of osteoblastic markers. In contrast, SB203580, a p38 MAPK pathway blocker, blocked RSVL-induced p38 phosphorylation, but resulted in an increase of cell proliferation and a more osteoblastic maturation. These data suggest that RSVL stimulates HBMSCs proliferation and osteoblastic differentiation through an ER-dependent mechanism and coupling to ERK1/2 activation.
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Wang Y, Dai H, Liu Z, Cheng X, Tellides G, Dai Z. Neutralizing IL-7 promotes long-term allograft survival induced by CD40/CD40L costimulatory blockade. Am J Transplant 2006; 6:2851-60. [PMID: 17062001 DOI: 10.1111/j.1600-6143.2006.01550.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Memory T cells are somewhat resistant to immunosuppresion. They therefore pose a threat to inducing long-term allograft survival. IL-7 is essential for memory T-cell generation. Here, we investigated whether neutralizing IL-7 promotes allograft survival. We found that neutralizing IL-7 alone did not significantly prolong allograft survival. However, blocking both IL-7 and CD154 signaling synergistically prolonged allograft survival. In contrast, neutralizing IL-2 failed to further prolong allograft survival induced by CD40/CD154 costimulatory blockade. Allospecific memory CD8+ T-cell generation was severely impaired under the treatment of anti-IL-7 plus anti-CD154 Ab while administering recombinant IL-7 enhanced CD8+ memory generation even under donor-specific transfusion plus anti-CD154 Ab treatment. Neutralizing IL-7, but not IL-2, together with blocking CD154 synergistically suppressed the proliferation of naïve/effector CD8+ T cells infiltrating grafts. Nevertheless, neutralizing IL-7 did not alter regulatory T-cell generation while neutralizing IL-2 suppressed their generation. Hence, targeting IL-7 represents a new strategy to prolong allograft survival by acting on both naïve and memory T cells. Long-term allograft survival may be achieved by neutralizing IL-7 plus CD40/CD154 blockade, since CD40/CD154 costimulatory blockade prevents acute rejection while neutralizing IL-7 suppresses the generation of memory T cells that persist and mediate late or chronic rejection.
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Dai Z, Ma SC, Wang GL, Wang F, Lin RC. A new glucoside from Selaginella sinensis. JOURNAL OF ASIAN NATURAL PRODUCTS RESEARCH 2006; 8:529-33. [PMID: 16931428 DOI: 10.1080/10286020500175874] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
A new glucoside, selaginoside (1), together with two known compounds, hinokiflavone (2) and 2,3-dihydroamentoflavone (3), were isolated from the whole plants of Selaginella sinensis. Their structures were elucidated by means of spectroscopic methods.
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Browning ND, Arslan I, Erni R, Idrobo JC, Ziegler A, Bradley J, Dai Z, Stach EA, Bleloch A. Monochromators and Aberration Correctors: Taking EELS to New Levels of Energy and Spatial Resolution. ACTA ACUST UNITED AC 2006. [DOI: 10.1088/1742-6596/26/1/014] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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119
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Huang Y, Blower PE, Yang C, Barbacioru C, Dai Z, Zhang Y, Xiao JJ, Chan KK, Sadée W. Correlating gene expression with chemical scaffolds of cytotoxic agents: ellipticines as substrates and inhibitors of MDR1. THE PHARMACOGENOMICS JOURNAL 2005; 5:112-25. [PMID: 15668728 DOI: 10.1038/sj.tpj.6500297] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
To facilitate a systematic study of chemoresistance across diverse classes of anticancer drug candidates, we performed correlation analyses between cytotoxic drug potency and gene expression in 60 tumor cell lines (NCI-60; NCI-National Cancer Institute). Ellipticine analogs displayed a range of correlation coefficients (r) with MDR1 (ABCB1, encoding multidrug resistance (MDR) protein MDR1 or P-glycoprotein). To determine MDR1 interactions of five ellipticines with diverse MDR1-r values, we employed MDR1-transport and cytotoxicity assays, using MDR1 inhibitors and siRNA-mediated MDR1 downregulation, in MDR1-overexpressing cells. Ellipticines with negative correlations-indicative of MDR1-mediated resistance-were shown to be MDR1 substrates, whereas those with neutral or positive correlations served as MDR1 inhibitors, which escape MDR1-mediated chemoresistance. Correlation with additional genes in the NCI-60 confirmed topoisomerases as ellipticine targets, but suggested distinct mechanisms of action and chemoresistance among them, providing a guide for selecting optimal drug candidates.
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MESH Headings
- ATP Binding Cassette Transporter, Subfamily B, Member 1/antagonists & inhibitors
- ATP Binding Cassette Transporter, Subfamily B, Member 1/metabolism
- Algorithms
- Antineoplastic Agents, Phytogenic/metabolism
- Antineoplastic Agents, Phytogenic/pharmacology
- Cell Survival/drug effects
- Cluster Analysis
- DNA Probes
- Databases, Factual
- Down-Regulation/drug effects
- Ellipticines/metabolism
- Ellipticines/pharmacology
- Flow Cytometry
- Fluorescent Dyes
- Gene Expression Regulation, Neoplastic/drug effects
- Genes, MDR/genetics
- Humans
- Medical Informatics
- Paclitaxel/toxicity
- Principal Component Analysis
- RNA, Small Interfering/genetics
- Reproducibility of Results
- Structure-Activity Relationship
- Tumor Cells, Cultured
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Duff MC, Hunter DB, Hobbs DT, Fink SD, Dai Z, Bradley JP. Mechanisms of strontium and uranium removal from high-level radioactive waste simulant solutions by the sorbent monosodium titanate. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2004; 38:5201-5207. [PMID: 15506218 DOI: 10.1021/es035415+] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
High-level waste (HLW) is a waste associated with the dissolution of spent nuclear fuel for the recovery of weapons-grade material. It is the priority problem for the U.S. Department of Energy's Environmental Management Program. Current HLW treatment processes at the Savannah River Site (Aiken, SC) include the use of monosodium titanate (MST, with a similar stoichiometry to NaTi2O5 x xH2O) to concentrate strontium (Sr) and actinides. The high affinity of MST for Sr and actinides in HLW solutions rich in Na+ is poorly understood. Mechanistic information about the nature of radionuclide uptake will provide insight about MST treatment reliability. Our study characterized the morphology of MST and the chemistry of sorbed Sr2+ and uranium [U(VI)] as uranyl ion, UO2(2+), on MST, which were added (individually) from stock solutions of Sr and 238U(VI) with spectroscopic and transmission electron microscopic techniques. The local structure of sorbed U varied with loading, but the local structure of Sr did not vary with loading. Sorbed Sr exhibited specific adsorption as partially hydrated species whereas sorbed U exhibited specific adsorption as monomeric and dimeric U(VI)-carbonate complexes. Sorption proved site specific. These differences in site specificity and sorption mechanism may account forthe difficulties associated with predicting Sr and U loading and removal kinetics using MST.
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Smiraglia DJ, Smith LT, Lang JC, Rush LJ, Dai Z, Schuller DE, Plass C. Differential targets of CpG island hypermethylation in primary and metastatic head and neck squamous cell carcinoma (HNSCC). J Med Genet 2003; 40:25-33. [PMID: 12525538 PMCID: PMC1735270 DOI: 10.1136/jmg.40.1.25] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Head and neck squamous cell carcinomas (HNSCC) often metastasise to the cervical lymph nodes. It is known for HNSCC as well as other cancers that progression from normal tissue to primary tumour and finally to metastatic tumour is characterised by an accumulation of genetic mutations. DNA methylation, an epigenetic modification, can result in loss of gene function in cancer, similar to genetic mutations such as deletions and point mutations. We have investigated the DNA methylation phenotypes of both primary HNSCC and metastatic tumours from 13 patients using restriction landmark genomic scanning (RLGS). With this technique, we were able to assess the methylation status of an average of nearly 1300 CpG islands for each tumour. We observed that the number of CpG islands hypermethylated in metastatic tumours is significantly greater than what is found in the primary tumours overall, but not in every patient. Interestingly, the data also clearly show that many loci methylated in a patient's primary tumour are no longer methylated in the metastatic tumour of the same patient. Thus, even though metastatic HNSCC methylate a greater proportion of CpG islands than do the primary tumours, they do so at different subsets of loci. These data show an unanticipated variability in the methylation state of loci in primary and metastatic HNSCCs within the same patient. We discuss two possible explanations for how different epigenetic events might arise between the primary tumour and the metastatic tumour of a person.
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Dai Z, Lakkis FG. Cutting edge: Secondary lymphoid organs are essential for maintaining the CD4, but not CD8, naive T cell pool. JOURNAL OF IMMUNOLOGY (BALTIMORE, MD. : 1950) 2001; 167:6711-5. [PMID: 11739484 DOI: 10.4049/jimmunol.167.12.6711] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Despite declining thymic output with age, the peripheral naive T cell pool of an adult animal remains remarkably stable. Therefore, a central question in immunology is how the naive T cell pool is maintained. Here we show that the maintenance of the naive CD4, but not CD8, T cell population in the thymectomized adult mouse is dependent on the presence of secondary lymphoid tissues. This finding is explained by the inability of naive CD4 T cells to sustain normal levels of the survival molecule Bcl-2 or to undergo homeostatic proliferation in the absence of secondary lymphoid organs. Thus, naive CD4 T cells must traffic through secondary lymphoid organs to maintain a stable CD4 pool while naive CD8 T cells encounter their survival and proliferation signals outside the organized structures of secondary lymphoid tissues.
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Zhao D, Dai Z, Zhou K, Zhang L. [Expression of the artificial cecropin CMIV-like gene of Chinese silkworm Bombyx mori in Laphygma exigua larvae]. WEI SHENG WU XUE BAO = ACTA MICROBIOLOGICA SINICA 2001; 41:680-5. [PMID: 12552823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/28/2023]
Abstract
The synthesized CMIV-like Gene was linked with the signal peptide gene of nature silkworm antibacterial peptide and was inserted into baculovirus expression vector pFastBac 1, construcing a recombinant transposing vector. The vector was transformed into DH10Bac competent E. coli cells. The recombinant Bacmid was obtained. The recombinant Bacmid was transfected into sf21 cells to get the recombinant virus. Laphygma exigua larvae were infected with the recombinant virus to express the antibacterial peptide. The hemolymph were tested to have antibacterial activity. The active antibacterial peptide was purified by acid polyacrylamide electrophoresis. The specific expression of mRNA of CMIV-like Gene was tested using Northern blotting.
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Zhu WG, Dai Z, Ding H, Srinivasan K, Hall J, Duan W, Villalona-Calero MA, Plass C, Otterson GA. Increased expression of unmethylated CDKN2D by 5-aza-2'-deoxycytidine in human lung cancer cells. Oncogene 2001; 20:7787-96. [PMID: 11753657 DOI: 10.1038/sj.onc.1204970] [Citation(s) in RCA: 87] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2001] [Revised: 09/05/2001] [Accepted: 09/13/2001] [Indexed: 11/09/2022]
Abstract
DNA hypermethylation of CpG islands in the promoter region of genes is associated with transcriptional silencing. Treatment with hypo-methylating agents can lead to expression of these silenced genes. However, whether inhibition of DNA methylation influences the expression of unmethylated genes has not been extensively studied. We analysed the methylation status of CDKN2A and CDKN2D in human lung cancer cell lines and demonstrated that the CDKN2A CpG island is methylated, whereas CDKN2D is unmethylated. Treatment of cells with 5-aza-2'-deoxycytidine (5-Aza-CdR), an inhibitor of DNA methyltransferase 1, induced a dose and duration dependent increased expression of both p16(INK4a) and p19(INK4d), the products of CDKN2A and CDKN2D, respectively. These data indicate that global DNA demethylation not only influences the expression of methylated genes but also of unmethylated genes. Histone acetylation is linked to methylation induced transcriptional silencing. Depsipeptide, an inhibitor of histone deacetylase, acts synergistically with 5-Aza-CdR in inducing expression of p16(INK4a) and p19(INK4d). However, when cells were treated with higher concentrations of 5-Aza-CdR and depsipeptide, p16(INK4a) expression was decreased together with significant suppression of cell growth. Interestingly, p19(INK4d) expression was enhanced even more by the higher concentrations of 5-Aza-CdR and depsipeptide. Our data suggest that p19(INK4d) plays a distinct role from other INK4 family members in response to the cytotoxicity induced by inhibition of DNA methylation and histone deacetylation.
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Dai Z, Yu X. [Yu Jinghe's Chronicle]. ZHONGHUA YI SHI ZA ZHI (BEIJING, CHINA : 1980) 2001; 27:52-6. [PMID: 11618968] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/21/2023]
Abstract
The life and origin of medical learning from family of Yu Jinghe, renowned doctor of the Qing Dynasty, are described here in the form of chronicle. He was born in Yixing, Jiangsu. His parent died when he was a boy and he joined the Taiping Army for 5 years with difficult experiences. Later, he moved to Menghe and learned pharmacology from his elder brother. His works include Yu's Annotation on Shanghanlun Yi, Collection of Case Records on External Diseases, Collection After Practising Hour etc. Moreover, Yu's descendents and his close relationship with other modern celebrated doctors such as Ding Ganren and his son Ding Zhongying, and Yun Tieqiao are also mentioned.
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