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Shin S, Kim S, Oh HE, Kong H, Shin E, Do SG, Jo TH, Park YI, Lee CK, Kim K. Dietary Aloe QDM Complex Reduces Obesity-Induced Insulin Resistance and Adipogenesis in Obese Mice Fed a High-Fat Diet. Immune Netw 2012; 12:96-103. [PMID: 22916045 PMCID: PMC3422715 DOI: 10.4110/in.2012.12.3.96] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2012] [Revised: 05/29/2012] [Accepted: 05/31/2012] [Indexed: 01/18/2023] Open
Abstract
Obesity-induced disorders contribute to the development of metabolic diseases such as insulin resistance, fatty liver diseases, and type 2 diabetes (T2D). In this study, we evaluated whether the Aloe QDM complex could improve metabolic disorders related to blood glucose levels and insulin resistance. Male C57BL/6 obese mice fed a high-fat diet for 54 days received a supplement of Aloe QDM complex or pioglitazone (PGZ) or metformin (Met) and were compared with unsupplemented controls (high-fat diet; HFD) or mice fed a regular diet (RD). RT-PCR and western blot analysis were used to quantify the expression of obesity-induced inflammation. Dietary Aloe QDM complex lowered body weight, fasting blood glucose, plasma insulin, and leptin levels, and markedly reduced the impairment of glucose tolerance in obese mice. Also, Aloe QDM complex significantly enhanced plasma adiponectin levels and insulin sensitivity via AMPK activity in muscles. At the same time, Aloe QDM decreased the mRNA and protein of PPARγ/LXRα and scavenger receptors in white adipose tissue (WAT). Dietary Aloe QDM complex reduces obesity-induced glucose tolerance not only by suppressing PPARγ/LXRα but also by enhancing AMPK activity in the WAT and muscles, both of which are important peripheral tissues affecting insulin resistance. The Aloe QDM complex could be used as a nutritional intervention against T2D.
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Chen X, Yang Q, Kong H, Chen Y. Real-time PCR and Amplified MTD® for rapid detection of Mycobacterium tuberculosis in pulmonary specimens. Int J Tuberc Lung Dis 2012; 16:235-9. [PMID: 22236926 DOI: 10.5588/ijtld.11.0212] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
SETTING Patients with suspected pulmonary tuberculosis (PTB) in the First Affiliated Hospital, College of Medicine, Zhejiang University. OBJECTIVE To evaluate the 'Care TB®' real-time polymerase chain reaction (PCR) assay in comparison with the Amplified MTD® Test (AMTD) for the rapid diagnosis of TB. DESIGN Self-expectorated sputum was collected for direct smear microscopy, culture, real-time PCR and AMTD assay. Performance of the 'Care TB' real-time PCR and AMTD assay were compared using a combination of culture and clinical diagnosis as a reference standard. RESULTS Of the 178 sputum specimens, 83 were culture-positive; of these, 74 were Mycobacterium tuberculosis complex and 9 strains were non-tuberculous mycobacteria. The overall sensitivities and specificities were respectively 91.6% and 100% for real-time PCR, and 95.2% and 97.9% for AMTD. In the smear-positive specimens, the sensitivities and specificities were respectively 97% and 100% for real-time PCR, and 98.5% and 100% for AMTD. In the smear-negative specimens, the sensitivities and specificities were 70.6% and 100% for real-time PCR, and 82.4% and 97.7% for AMTD. CONCLUSIONS Both real-time PCR and AMTD are rapid and specific tests for detecting M. tuberculosis complex; however, 'Care TB' real-time PCR is more convenient and economical.
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Kong H, Li Z, Yuan L, Guan RM. The anti-hypoxia effect of Ginsenosides-Rbl on hypoxia cardiomyocytes mediated by the apelin-APJ system ex vivo. BRITISH HEART JOURNAL 2011. [DOI: 10.1136/heartjnl-2011-300867.130] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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Kong H, Sun H, Xu G, Song L. Ginsenosides-Rbl exerts beneficial effects on left ventricular dysfunction and remodelling early after myocardial infarction. BRITISH HEART JOURNAL 2011. [DOI: 10.1136/heartjnl-2011-300867.131] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Kong H, Sun H, Song L. Effects of Ginsenosides-Rbl inhibiting cardiomyocyte hypertrophy via NHE-1-dependent calcineurin activation ex vivo. BRITISH HEART JOURNAL 2011. [DOI: 10.1136/heartjnl-2011-300867.132] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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81
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Shin E, Shin S, Kong H, Lee S, Do SG, Jo TH, Park YI, Lee CK, Hwang IK, Kim K. Dietary Aloe Reduces Adipogenesis via the Activation of AMPK and Suppresses Obesity-related Inflammation in Obese Mice. Immune Netw 2011; 11:107-13. [PMID: 21637388 PMCID: PMC3100521 DOI: 10.4110/in.2011.11.2.107] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2011] [Revised: 03/28/2011] [Accepted: 03/31/2011] [Indexed: 01/15/2023] Open
Abstract
Background Metabolic disorders, including type II diabetes and obesity, present major health risks in industrialized countries. AMP-activated protein kinase (AMPK) has become the focus of a great deal of attention as a novel therapeutic target for the treatment of metabolic syndromes. In this study, we evaluated whether dietary aloe could reduce obesity-induced inflammation and adipogenesis. Methods Male C57BL/6 obese mice fed a high-fat diet for 54 days received a supplement of aloe formula (PAG, ALS, Aloe QDM, and Aloe QDM complex) or pioglitazone (PGZ) and were compared with unsupplemented controls (high-fat diet; HFD) or mice fed a regular diet (RD). RT-PCR and western blot analysis were used to quantify the expression of obesity-induced inflammation. Results Aloe QDM complex down-regulated fat size through suppressed expression of scavenger receptors on adipose tissue macrophages (ATMs) compared with HFD. Both white adipose tissue (WATs) and muscle exhibited increased AMPK activation through aloe supplementation, and in particular, the Aloe QDM complex. Obesity-induced inflammatory cytokines (IL-1β and -6) and HIF1α mRNA and protein were decreased markedly, as was macrophage infiltration by the Aloe QDM complex. Further, the Aloe QDM complex decreased the translocation of NF-κB p65 from the cytosol in the WAT. Conclusion Dietary aloe formula reduced obesity-induced inflammatory responses by activation of AMPK in muscle and suppression of proinflammatory cytokines in the WAT. Additionally, the expression of scavenger receptors in the ATM and activation of AMPK in WAT led to reduction in the percent of body fat. Thus, we suggest that the effect of the Aloe QDM complex in the WAT and muscle are related to activation of AMPK and its use as a nutritional intervention against T2D and obesity-related inflammation.
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Abstract
Mutations in the transcription factors PAX9 and MSX1 cause selective tooth agenesis in humans. In tooth bud mesenchyme of mice, both proteins are required for the expression of Bmp4, which is the key signaling factor for progression to the next step of tooth development. We have previously shown that Pax9 can transactivate a 2.4-kb Bmp4 promoter construct, and that most tooth-agenesis-causing PAX9 mutations impair DNA binding and Bmp4 promoter activation. We also found that Msx1 by itself represses transcription from this proximal Bmp4 promoter, and that, in combination with Pax9, it acts as a potentiator of Pax9-induced Bmp4 transactivation. This synergism of Msx1 with Pax9 is significant, because it is currently the only documented mechanism for Msx1-mediated activation of Bmp4. In this study, we investigated whether the 5 known tooth-agenesis-causing MSX1 missense mutations disrupt this Pax9-potentiation effect, or if they lead to deficiencies in protein stability, protein-protein interactions, nuclear translocation, and DNA-binding. We found that none of the studied molecular mechanisms yielded a satisfactory explanation for the pathogenic effects of the Msx1 mutations, calling for an entirely different approach to the investigation of this step of odontogenesis on the molecular level.
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Shin E, Shim KS, Kong H, Lee S, Shin S, Kwon J, Jo TH, Park YI, Lee CK, Kim K. Dietary Aloe Improves Insulin Sensitivity via the Suppression of Obesity-induced Inflammation in Obese Mice. Immune Netw 2011; 11:59-67. [PMID: 21494375 PMCID: PMC3072676 DOI: 10.4110/in.2011.11.1.59] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2011] [Revised: 01/13/2011] [Accepted: 01/20/2011] [Indexed: 12/15/2022] Open
Abstract
Background Insulin resistance is an integral feature of metabolic syndromes, including obesity, hyperglycemia, and hyperlipidemia. In this study, we evaluated whether the aloe component could reduce obesity-induced inflammation and the occurrence of metabolic disorders such as blood glucose and insulin resistance. Methods Male C57BL/6 obese mice fed a high-fat diet for 54 days received a supplement of aloe formula (PAG, ALS, Aloe QDM, and Aloe QDM complex) or pioglitazone (PGZ) and were compared with unsupplemented controls (high-fat diet; HFD) or mice fed a regular diet (RD). RT-PCR and western blot analysis were used to quantify the expression of obesity-induced inflammation. Results Aloe QDM lowered fasting blood glucose and plasma insulin compared with HFD. Obesity-induced inflammatory cytokine (IL-1β, -6, -12, TNF-α) and chemokine (CX3CL1, CCL5) mRNA and protein were decreased markedly, as was macrophage infiltration and hepatic triglycerides by Aloe QDM. At the same time, Aloe QDM decreased the mRNA and protein of PPARγ/LXRα and 11β-HSD1 both in the liver and WAT. Conclusion Dietary aloe formula reduces obesity-induced glucose tolerance not only by suppressing inflammatory responses but also by inducing anti-inflammatory cytokines in the WAT and liver, both of which are important peripheral tissues affecting insulin resistance. The effect of Aloe QDM complex in the WAT and liver are related to its dual action on PPARγ and 11β-HSD1 expression and its use as a nutritional intervention against T2D and obesity-related inflammation is suggested.
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Kong H, Kuang W, Li S, Xu M. Activation of dopamine D3 receptors inhibits reward-related learning induced by cocaine. Neuroscience 2010; 176:152-61. [PMID: 21168475 DOI: 10.1016/j.neuroscience.2010.12.008] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2010] [Revised: 12/03/2010] [Accepted: 12/06/2010] [Indexed: 01/10/2023]
Abstract
Memories of learned associations between the rewarding properties of drugs and environmental cues contribute to craving and relapse in humans. The mesocorticolimbic dopamine (DA) system is involved in reward-related learning induced by drugs of abuse. DA D3 receptors are preferentially expressed in mesocorticolimbic DA projection areas. Genetic and pharmacological studies have shown that DA D3 receptors suppress locomotor-stimulant effects of cocaine and reinstatement of cocaine-seeking behaviors. Activation of the extracellular signal-regulated kinase (ERK) induced by acute cocaine administration is also inhibited by D3 receptors. How D3 receptors modulate cocaine-induced reward-related learning and associated changes in cell signaling in reward circuits in the brain, however, have not been fully investigated. In the present study, we show that D3 receptor mutant mice exhibit potentiated acquisition of conditioned place preference (CPP) at low doses of cocaine compared to wild-type mice. Activation of ERK and CaMKIIα, but not the c-Jun N-terminal kinase and p38, in the nucleus accumbens, amygdala and prefrontal cortex is also potentiated in D3 receptor mutant mice compared to that in wild-type mice following CPP expression. These results support a model in which D3 receptors modulate reward-related learning induced by low doses of cocaine by inhibiting activation of ERK and CaMKIIα in reward circuits in the brain.
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Kong H, Li Z, Zhang W, Yuan L, Hou A. e0045 Effects of Ginsenoside-Rbl on aldosterone-induced elastin production in rat cardiac fibroblasts ex vivo. BRITISH HEART JOURNAL 2010. [DOI: 10.1136/hrt.2010.208967.45] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
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86
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Xing B, Kong H, Meng X, Wei S, Xu M, Li S. Dopamine D1 but not D3 receptor is critical for spatial learning and related signaling in the hippocampus. Neuroscience 2010; 169:1511-9. [DOI: 10.1016/j.neuroscience.2010.06.034] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2010] [Revised: 06/14/2010] [Accepted: 06/16/2010] [Indexed: 12/30/2022]
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Shin S, Kwon J, Lee S, Kong H, Lee S, Lee CK, Cho K, Ha NJ, Kim K. Immunostimulatory Effects of Cordyceps militaris on Macrophages through the Enhanced Production of Cytokines via the Activation of NF-kappaB. Immune Netw 2010; 10:55-63. [PMID: 20532125 PMCID: PMC2881426 DOI: 10.4110/in.2010.10.2.55] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 03/25/2010] [Accepted: 03/31/2010] [Indexed: 02/02/2023] Open
Abstract
Background Cordyceps militaris has been used in traditional medicine to treat numerous diseases and has been reported to possess both antitumor and immunomodulatory activities in vitro and in vivo. However, the pharmacological and biochemical mechanisms of Cordyceps militaris extract (CME) on macrophages have not been clearly elucidated. In the present study, we examined how CME induces the production of proinflammatory cytokines, transcription factor, and the expression of co-stimulatory molecules. Methods We confirmed the mRNA and protein levels of proinflammatory cytokines through RT-PCR and western blot analysis, followed by a FACS analysis for surface molecules. Results CME dose dependently increased the production of NO and proinflammatory cytokines such as IL-1β, IL-6, TNF-α, and PGE2, and it induced the protein levels of iNOS, COX-2, and proinflammatory cytokines in a concentration-dependent manner, as determined by western blot and RT-PCR analysis, respectively. The expression of co-stimulatory molecules such as ICAM-1, B7-1, and B7-2 was also enhanced by CME. Furthermore, the activation of the nuclear transcription factor, NF-κB in macrophages was stimulated by CME. Conclusion Based on these observations, CME increased proinflammatory cytokines through the activation of NF-κB, further suggesting that CME may prove useful as an immune-enhancing agent in the treatment of immunological disease.
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Liu C, Zhang J, Zhang N, Shan H, Su K, Zhang J, Meng Z, Kong H, Chen Z. Interactions among Proteins of Floral MADS-Box Genes in Basal Eudicots: Implications for Evolution of the Regulatory Network for Flower Development. Mol Biol Evol 2010; 27:1598-611. [DOI: 10.1093/molbev/msq044] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Kim K, Kim H, Kwon J, Lee S, Kong H, Im SA, Lee YH, Lee YR, Oh ST, Jo TH, Park YI, Lee CK, Kim K. Hypoglycemic and hypolipidemic effects of processed Aloe vera gel in a mouse model of non-insulin-dependent diabetes mellitus. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2009; 16:856-863. [PMID: 19303272 DOI: 10.1016/j.phymed.2009.02.014] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2008] [Revised: 11/28/2008] [Accepted: 02/10/2009] [Indexed: 05/27/2023]
Abstract
The effects of processed Aloe vera gel (PAG) on the course of established diet-induced non-insulin-dependent diabetes mellitus (NIDDM) were studied in C57BL/6J mice. NIDDM was induced in C57BL/6J mice by feeding them a high-fat diet. Mice exhibiting diet-induced obesity (DIO) with blood glucose levels above 180mg/dl were selected to examine the antidiabetic effects of PAG. Oral administration of PAG for 8 weeks reduced circulating blood glucose concentrations to a normal level in these DIO mice. In addition, the administration of PAG significantly decreased plasma insulin. The antidiabetic effects of PAG were also confirmed by intraperitoneal glucose tolerance testing. PAG appeared to lower blood glucose levels by decreasing insulin resistance. The administration of PAG also lowered triacylglyceride levels in liver and plasma. Histological examinations of periepididymal fat pad showed that PAG reduced the average size of adipocytes. These results demonstrate that the oral administration of PAG prevents the progression of NIDDM-related symptoms in high-fat diet-fed mice, and suggest that PAG could be useful for treating NIDDM.
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Li X, Kong H, Wu W, Xiao M, Sun X, Hu G. Aquaporin-4 maintains ependymal integrity in adult mice. Neuroscience 2009; 162:67-77. [PMID: 19393298 DOI: 10.1016/j.neuroscience.2009.04.044] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2009] [Revised: 04/10/2009] [Accepted: 04/18/2009] [Indexed: 01/16/2023]
Abstract
Ependymal cells form the walls of the ventricles, and take part in the production of cerebrospinal fluid (CSF). Aquaporin-4 (AQP4), a predominant water channel of the brain, is restricted to basolateral plasma membranes of ependymal cells. The highly polarized expression of AQP4 suggests it may be involved in maintaining the structural and functional integrity of the ependyma. This hypothesis was validated by using adult AQP4 knockout mice generated by our laboratory [Fan Y, Zhang J, Sun XL, Gao L, Zeng XN, Ding JH, Cao C, Niu L, Hu G (2005) Sex- and region-specific alterations of basal amino acid and monoamine metabolism in the brain of aquaporin-4 knockout mice. J Neurosci Res 82:458-464]. Histological analysis showed disorganized ependymal layer of the lateral ventricle and aqueduct in AQP4-deficiency mice. A majority (92.7%) of null mice displayed reduced lateral ventricular volume, while a small fraction (7.3%) had enlarged or normal ventricular size with a narrow aqueduct. Immunohistochemistry demonstrated that AQP4 deletion resulted in decreased expression of gap junction protein connexin43 in the ependymal cells. Electron microscopy confirmed junctional complex absence at basolateral membranes of ependymocytes. Moreover, AQP4 knockout mice showed decreased CSF production and increased brain water content compared with wild-type mice. These results highlight a key role of AQP4 in maintaining the structure and function of the ependyma. In addition, variable profiles of ventricle system in adult AQP4 null mice indicate functional AQP4 polymorphisms.
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Meng J, Yang M, Song L, Kong H, Wang CY, Wang R, Wang C, Xie SS, Xu HY. Concentration control of carbon nanotubes in aqueous solution and its influence on the growth behavior of fibroblasts. Colloids Surf B Biointerfaces 2009; 71:148-53. [PMID: 19250807 DOI: 10.1016/j.colsurfb.2009.01.020] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2008] [Revised: 01/12/2009] [Accepted: 01/28/2009] [Indexed: 11/16/2022]
Abstract
This work investigated the biological influence of water-soluble multiwalled carbon nanotubes (wsMWCNTs) on fibroblast cell growth as a function of concentration control in an aqueous solution. The wsMWCNTs were prepared by an optimal procedure of ultrasonication/concentrated acids oxidation. The concentration of wsMWCNT in the solution was quantified by an established calibration line. A stable concentration of 0.3mg/ml was obtained in the surfactant-free water. The physicochemical properties of wsMWCNTs were characterized using scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), UV/VIS/NIR spectroscopy, and dynamic light scattering (DLS). Cell proliferation and the cell cycle were examined by MTS assay, flow cytometry and TEM respectively. Experimental results showed that the oxidation degree was a key factor that determined the concentration and stability of wsMWCNTs in the aqueous solution. The wsMWCNTs were able to enter into the cells and mainly accumulated in the cytoplasm. The wsMWCNTs-induced variations in cell proliferation and the cell cycle were concentration dependent. Cells cultivated with wsMWCNTs of 0.3mg/ml underwent a dramatic apoptosis. The proliferation was clearly suppressed when the cells were cultivated with wsMWCNTs of 0.03 mg/ml. There were no obvious influences on cell proliferation and the cell cycle when the concentration of wsMWNTs decreased to 0.01 mg/ml.
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Kim K, Lee S, Kim H, Han S, Kwon J, Shin S, Kong H, Yim D, Lee C. Immunomodulatory activities of arctiin isolated from a Fruit of Forsythia viridissima in macrophages. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1065.18] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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93
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Kim K, Shin S, Kwon J, Lee S, Kong H, Lee C. Immunostimulatory activities of CMB, the water extract of Cordyceps militaris fruit bodies, in primary macrophages. FASEB J 2008. [DOI: 10.1096/fasebj.22.1_supplement.1065.21] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Reisine T, Woulfe D, Raynor K, Kong H, Heerding J, Hines J, Tallent M, Law S. Interaction of somatostatin receptors with G proteins and cellular effector systems. CIBA FOUNDATION SYMPOSIUM 2007; 190:160-7; discussion 167-70. [PMID: 7587645 DOI: 10.1002/9780470514733.ch10] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Somatostatin induces its multiple biological actions by interacting with a family of receptors, referred to as sstr1-sstr5. To determine the molecular mechanisms of action of somatostatin, we have investigated the interaction of the different cloned receptors with G proteins and cellular effector systems. sstr2, sstr3 and sstr5 associate with pertussis toxin-sensitive G proteins and are able to mediate the inhibition of adenylyl cyclase activity by somatostatin. Two forms of sstr2, sstr2A and sstr2B, are generated by alternative splicing and differ in their C-terminal amino acid sequence. sstr2B couples to adenylyl cyclase whereas sstr2A does not. To investigate the basis for the differential coupling to adenylyl cyclase, we truncated sstr2B to the point of amino acid sequence divergence from sstr2A. The truncated sstr2B mediated the inhibition of cAMP formation by somatostatin, indicating that the C-terminus is not needed for coupling sstr2 to adenylyl cyclase. It is likely that the C-terminus of sstr2A hinders coupling to adenylyl cyclase. sstr2A associates with Gi alpha 3 and G(o) alpha but does not effectively interact with Gi alpha 1, a G protein that is necessary for coupling somatostatin receptors to adenylyl cyclase. The differential association of the splice variants with Gi alpha 1 may explain their contrasting effects on adenylyl cyclase activity. sstr3 also couples to adenylyl cyclase. Gi alpha 1 links sstr3 to adenylyl cyclase and mutagenesis studies have shown that the C-terminus of Gi alpha 1 is necessary for this coupling. The C-terminus of the Gi alpha proteins differ by only a few amino acid residues and only Gi alpha 1 couples sstr3 to adenylyl cyclase.(ABSTRACT TRUNCATED AT 250 WORDS)
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Bell GI, Yasuda K, Kong H, Law SF, Raynor K, Reisine T. Molecular biology of somatostatin receptors. CIBA FOUNDATION SYMPOSIUM 2007; 190:65-79; discussion 80-8. [PMID: 7587653 DOI: 10.1002/9780470514733.ch5] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The diverse physiological effects of somatostatin are mediated by a family of cell surface receptors that bind somatostatin selectively and with high affinity. The somatostatin receptors are members of the seven transmembrane segment receptor superfamily and molecular cloning studies have identified five types, designated sstr1-5. The human somatostatin receptors vary in size from 364 (sstr5) to 418 (sstr3) amino acids with 46-61% amino acid identity between receptors, and 105 amino acids are invariant. The sequences of the seven putative alpha-helical membrane-spanning domains are more highly conserved than those of the extracellular N- and intracellular C-terminal domains. Two forms of sstr2 have been identified in the mouse, sstr2A and sstr2B, which differ in size and sequence of the intracellular C-terminal domain. These two forms of sstr2 are products of a common gene and are generated by alternative splicing with sstr2A and sstr2B being the products of the unspliced and spliced forms, respectively, of sstr2 mRNA. Thus, functional diversity within the somatostatin receptor family may result from the expression of multiple types as well as from alternative splicing. The five somatostatin receptors have distinct patterns of expression in the central nervous system and peripheral tissues. They have also been expressed in vitro and shown to have different pharmacological properties. Somatostatin analogues selective for sstr2, sstr3 and sstr5 have been identified which will facilitate in vivo studies of the functions of these somatostatin receptors. Such studies to date suggest that sstr2 mediates inhibition of growth hormone secretion and sstr5 mediates inhibition of insulin secretion. The molecular cloning and functional characterization of the somatostatin receptor family is a first step in elucidating the diverse effects of somatostatin on cellular functions.
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Jin Y, Kong H, Wells G, Sykes J, Prato F. Po-Thur Eve General-22: 111In-Tropolone-Labeled Mesenchymal Stem Cells: In Vivo Radiotracer Kinetics. Med Phys 2006. [DOI: 10.1118/1.2244649] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
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Meng J, Kong H, Xu HY, Song L, Wang CY, Xie SS. Improving the blood compatibility of polyurethane using carbon nanotubes as fillers and its implications to cardiovascular surgery. J Biomed Mater Res A 2005; 74:208-14. [PMID: 15962271 DOI: 10.1002/jbm.a.30315] [Citation(s) in RCA: 78] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Blood compatibility has been an occlusion for biomaterials used in the cardiovascular system. In this work, a multiwalled carbon nanotubes-polyurethane composite (MWNT-PU) was prepared through a controlled co-precipitation. The surface chemical composition of treated carbon nanotubes was analyzed with XPS and the thermal behaviors of composite were characterized by DSC. The platelet adhesion and activation caused by the composite were evaluated by using SEM and flow cytometric analysis, respectively, and the disruption of red blood cells was analyzed through measuring the absorbance of free hemoglobin. The experimental results demonstrated that: (1) Multiwalled carbon nanotubes (MWNTs) with oxygen-containing functional groups could be well dispersed in polyurethane matrix through a controlled coprecipitation; (2) the composite surface displayed a significantly improved anticoagulant function, which can be indicative of the promising potentials of carbon nanotube-based materials in the implants and medical devices applied in blood-contacting environments.
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Xu Y, Lunnen KD, Kong H. Engineering a nicking endonuclease N.AlwI by domain swapping. Proc Natl Acad Sci U S A 2001; 98:12990-5. [PMID: 11687651 PMCID: PMC60812 DOI: 10.1073/pnas.241215698] [Citation(s) in RCA: 59] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Changing enzymatic function through genetic engineering still presents a challenge to molecular biologists. Here we present an example in which changing the oligomerization state of an enzyme changes its function. Type IIs restriction endonucleases such as AlwI usually fold into two separate domains: a DNA-binding domain and a catalytic/dimerization domain. We have swapped the putative dimerization domain of AlwI with a nonfunctional dimerization domain from a nicking enzyme, N.BstNBI. The resulting chimeric enzyme, N.AlwI, no longer forms a dimer. Interestingly, the monomeric N.AlwI still recognizes the same sequence as AlwI but only cleaves the DNA strand containing the sequence 5'-GGATC-3' (top strand). In contrast, the wild-type AlwI exists as a dimer in solution and cleaves two DNA strands; the top strand is cleaved by an enzyme binding to that sequence, and its complementary bottom strand is cleaved by the second enzyme dimerized with the first enzyme. N.AlwI is unable to form a dimer and therefore nicks DNA as a monomer. In addition, the engineered nicking enzyme is at least as active as the wild-type AlwI and is thus a useful enzyme. To our knowledge, this is the first report of creating a nicking enzyme by domain swapping.
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Besnier CE, Kong H. Converting MlyI endonuclease into a nicking enzyme by changing its oligomerization state. EMBO Rep 2001; 2:782-6. [PMID: 11520857 PMCID: PMC1084030 DOI: 10.1093/embo-reports/kve175] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
N.BstNBI is a nicking endonuclease that recognizes the sequence GAGTC and nicks one DNA strand specifically. The Type IIs endonuclease, MlyI, also recognizes GAGTC, but cleaves both DNA strands. Sequence comparisons revealed significant similarities between N.BstNBI and MlyI. Previous studies showed that MlyI dimerizes in the presence of a cognate DNA, whereas N.BstNBI remains a monomer. This suggests that dimerization may be required for double-stranded cleavage. To test this hypothesis, we used a multiple alignment to design mutations to disrupt the dimerization function of MlyI. When Tyr491 and Lys494 were both changed to alanine, the mutated endonuclease, N.MlyI, no longer formed a dimer and cleaved only one DNA strand specifically. Thus, we have shown that changing the oligomerization state of an enzyme changes its enzymatic function. This experiment also established a protocol that could be applied to other Type IIs endonucleases in order to generate more novel nicking endonucleases.
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Kong H, Gu X, Bass JL, Titus J, Urness M, Kim TH, Hunter DW. Experimental evaluation of a modified Amplatzer duct occluder. Catheter Cardiovasc Interv 2001; 53:571-6. [PMID: 11515016 DOI: 10.1002/ccd.1225] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The purpose of this study was to evaluate a new device specifically designed for patent ductus arteriosus (PDA) occlusion based on PDA anatomy. Percutaneous closure of aortopulmonary shunts was attempted in 10 dogs. Shunts were surgically created in the location and orientation of PDA. The occlusion prosthesis consisted of a cylindrical frame filled with polyester and a 32 degree angled retention disk. The delivery system of the device included a 6 Fr thin-walled Teflon introducing sheath, an antirotating delivery catheter, and cable. Complete occlusion of the shunt was obtained in nine animals. One animal died before device placement. Temporary hemolysis occurred in one dog after device placement. The disk of device was completely covered by smooth glistening neoendothelium at 1-3 months postmortem examination. None of the devices protruded into the lumen of the aorta. The device is an improvement over the standard Amplatzer duct occluder. The angled retention disk lies flatly against the aortic wall, avoiding turbulence or an aortic pressure gradient.
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