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Leung KS, Li YH, Liu Y, Wang H, Tam KF, Chow D, Wan Y, Ling S, Dai Z, Qin L, Cheung WH. Effect of daily short-duration weight-bearing on disuse-induced deterioration of musculoskeletal system. JOURNAL OF MUSCULOSKELETAL & NEURONAL INTERACTIONS 2015; 15:207-14. [PMID: 26032214 PMCID: PMC5133725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
OBJECTIVES To investigate deterioration of musculoskeletal system due to prolonged disuse and the potential of daily short-duration weight-bearing as countermeasures. METHODS Twenty-four adult male Sprague-Dawley rats were divided into Control Group (CG, no intervention), Tail-suspension Group (TG, tail-suspension without treatment), and Weight-Bearing Group (WBG, tail-suspension with 20 min/day, 5 days/week body weight loading). After four weeks of treatment, femur and tibia, soleus and extensor digitorum longus were evaluated for bone and muscle quality respectively. Tensile properties of bone-tendon insertion (BTI) were evaluated using patella-patellar tendon complex. RESULTS Disuse induced deterioration on bone, muscle, and BTI after four weeks. Compared with CG, TG and WBG showed significant decrease in bone mineral density (BMD) of trabecular bone in distal femur (4.3-15.2%), muscle mass (31.3-52.3%), muscle cross-sectional area (29.1-35%), and failure strength of BTI (23.9-29.4%). Tensile test showed that the failure mode was avulsion of bone at the BTI. No significant difference was detected between TG and WBG for all assessments on bone, muscle, and BTI. CONCLUSIONS Disuse caused deterioration of bone, muscle, and BTI while daily short-duration of weight-bearing did not prevent this deterioration. Mechanical stimulation with higher intensity and longer duration may be necessary to prevent musculoskeletal deterioration resulted from prolonged disuse.
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Zhang S, Gao X, Ma Y, Jiang J, Dai Z, Yin X, Min W, Hui W, Wang B. Expression and significance of SATB1 in the development of breast cancer. GENETICS AND MOLECULAR RESEARCH 2015; 14:3309-17. [PMID: 25966097 DOI: 10.4238/2015.april.13.10] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Special AT-rich sequence binding protein 1 (SATB1) is a recently discovered gene regulator that can promote the growth and metastasis of breast cancer. However, its expression in different stages of breast cancer development have not been examined. We explored the role of SATB1 in the development of breast cancer by detecting SATB1 expression levels in different stages of breast cancer. SATB1 expression was determined using an immunohistochemical streptavidin peroxidase method; the relationship between clinicopathological features of breast cancer and SATB1 expression was analyzed using the X(2) test. Positive rates of SATB1 protein in normal breast tissue, normal breast ductal hyperplasia tissue, precancerous lesions of breast cancer, non-invasive cancer, early invasive carcinoma, and invasive breast cancer tissue were, respectively, 6.25 (2/32), 6.4 (3/47), 20.4 (10/49), 45.0 (9/20), 52.9 (9/17), and 76.6% (72/94). SATB1 in the latter 3 groups was significantly higher than in the first 3 groups (P < 0.05). The positive rate of SATB1 protein in invasive non-special types of breast cancer (88.5%, 54/61) was significantly higher than in the special type of invasive breast cancer (54.5%, 18/33) and early invasive breast cancer (52.9%, 9/17) (P < 0.05). SATB1 protein expression in breast cancer with lymph node metastasis was generally increased, and the difference was statistically significant (P < 0.05). SATB1 protein expression showed an increasing trend in different stages of breast cancer development. Overexpression indicated poor prognosis.
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Pang J, He X, Ma C, Zhao L, Li Q, Dai Z. Hybrid monitor for both beam position and tilt of pulsed high-current beams. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:093305. [PMID: 25273717 DOI: 10.1063/1.4895643] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
A Hybrid beam monitor, integrated with both azimuthal and axial B-dot probes, was designed for simultaneous measurement of both beam position and beam angle for pulsed high-current beams at the same location in beam pipe. The output signals of axial B-dot probes were found to be mixed with signals caused by transverse position deviation. In order to eliminate the unwanted signals, an elimination method was developed and its feasibility tested on a 50-Ω coaxial line test stand. By this method, a waveform, shape-like to that of input current and proportional to the tilt angle, was simulated and processed by following integration step to achieve the tilt angle. The tests showed that the measurement error of displacement and tilt angle less than 0.3 mm and 1.5 mrad, respectively. The latter error could be reduced with improved probes by reducing the inductance of the axial B-dot probe, but the improvement reached a limit due to some unknown systemic mechanism.
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Brang D, Towle VL, Suzuki S, Dai Z, Hillyard SA, Kohrman MH, Tao JX, Grabowecky M. Electrocorticographic (ECoG) recordings demonstrate that peripherally presented sounds activate extrastriate visual cortex. J Vis 2014. [DOI: 10.1167/14.10.1134] [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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Zhu X, Liu Y, Zhao P, Dai Z, Yang X, Li Y, Qiu M, Zhang Z. Gpr177-mediated Wnt Signaling is Required for Fungiform Placode Initiation. J Dent Res 2014; 93:582-8. [PMID: 24736288 DOI: 10.1177/0022034514531985] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2013] [Accepted: 03/24/2014] [Indexed: 11/15/2022] Open
Abstract
Fungiform papillae are formed as patterned rows on the surface of the anterior tongue at early organogenesis and contain one taste bud in each papilla to form one of the important sensory organs. Despite the essential role of Wnt/β-catenin signaling in controlling the development of fungiform taste papillae, the universal function of Wnt ligands in the initiation of the fungiform placode has not been completely elucidated. Here, by Shh (Cre) -mediated oral epithelial deletion of Wntless (Gpr177), a regulator essential for intracellular Wnt trafficking, we demonstrate that an overall function of Wnts is required for initiation of the fungiform placode. Multiple Wnts are expressed in the tongue epithelium at E11.5 before initiation of the fungiform placodes. Epithelial Gpr177 loss-of-function, associated with reduction of canonical Wnt signaling in lingual epithelium as exhibited by a loss of TopGal activity and Axin2 expression, results in the failure of fungiform placode initiation, as assessed by diminished expression of several taste placode molecular markers. Moreover, LiCl treatment of Gpr177 epithelial-deficient tongue explants at E11.5, but not at E12.5, restores tongue placode formation, demonstrating that Wnt ligands in the tongue surface prior to but not after fungiform placode initiation are responsible for fungiform papilla initiation. Epithelium-specific expression of an active β-catenin in the Gpr177-deficient tongue leads to fungiform papillae generation, suggesting that an intra-epithelial response to Wnts is required for placode initiation. Together, these results suggest that Gpr177 controls epithelial initiation of the fungiform placode through signaling via epithelial Wnt ligands.
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Dai Z, Zhang S, Xie Q, Wu S, Su J, Li S, Xu Y, Li XC. Natural CD8+CD122+ T cells are more potent in suppression of allograft rejection than CD4+CD25+ regulatory T cells. Am J Transplant 2014; 14:39-48. [PMID: 24219162 DOI: 10.1111/ajt.12515] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2013] [Revised: 08/12/2013] [Accepted: 08/13/2013] [Indexed: 01/25/2023]
Abstract
Despite extensive studies on CD4+CD25+ regulatory T cells (Tregs), their application in adoptive transfer therapies is still not optimal in immune-competent wild-type (WT) animal models. Therefore, it is compelling to search for more potent Tregs for potential clinical application. Mounting evidence has shown that naturally occurring CD8+CD122+ T cells are also Tregs. However, their suppression in allograft rejection, efficiency in suppression and underlying mechanisms remain unclear. Using a murine allotransplantation model, we reported here that CD8+CD122+ Tregs were actually more potent in suppression of allograft rejection and underwent more rapid homeostatic proliferation than their CD4+CD25+ counterparts. Moreover, they produced more IL-10 and were more potent in suppressing T cell proliferation in vitro. Deficiency in IL-10 in CD4+CD25+ and CD8+CD122+ Tregs resulted in their reduced but equal suppression in vivo and in vitro, suggesting that IL-10 is responsible for more effective suppression by CD8+CD122+ than CD4+CD25+ Tregs. Importantly, transfer of CD8+CD122+ Tregs together with the administration of recombinant IL-15 significantly prolonged allograft survival in WT mice. Thus, for the first time, we demonstrate that naturally arising CD8+CD122+ Tregs not only inhibit allograft rejection but also exert this suppression more potently than their CD4+CD25+ counterparts. This novel finding may have important implications for tolerance induction.
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El-Gazzar A, Cai X, Reeves RS, Dai Z, Caballero-Benitez A, McDonald DL, Vazquez J, Gooley TA, Sale GE, Spies T, Groh V. Effects on tumor development and metastatic dissemination by the NKG2D lymphocyte receptor expressed on cancer cells. Oncogene 2013; 33:4932-40. [PMID: 24141776 PMCID: PMC3994187 DOI: 10.1038/onc.2013.435] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 09/13/2013] [Indexed: 12/16/2022]
Abstract
The stimulatory NKG2D lymphocyte receptor together with its tumor-associated ligands enable the immune system to recognize and destroy cancer cells. However, with dynamic changes unfolding, cancers exploit NKG2D and its ligands for immune evasion and suppression. Recent findings have added yet another functional dimension wherein cancer cells themselves coopt NKG2D for their own benefit to complement the presence of its ligands for self stimulation of parameters of tumorigenesis. Those findings are here extended to in vivo tumorigenicity testing by employing orthotopic xenotransplant breast cancer models in mice. Using human cancer lines with ectopic NKG2D expression and RNAi-mediated protein depletion among other controls, we show that NKG2D self-stimulation has tumor promoting capacity. NKG2D signals had no notable effects on cancer cell proliferation and survival but acted at the level of angiogenesis, thus promoting tumor growth, tumor cell intravasation and dissemination. NKG2D-mediated effects on tumor initiation may represent another factor in the observed overall enhancement of tumor development. Altogether, these results may impact immunotherapy approaches, which currently do not account for such NKG2D effects in cancer patients and thus could be misdirected as underlying assumptions are incomplete.
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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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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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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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97
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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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98
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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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99
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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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100
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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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