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Li H, Xu Y, Guan R, Matheu M, Lei H, Tian W, Gao Z, Lin G, Guo Y, Xin Z, Song W. Icariside II prevents high-glucose-induced injury on human cavernous endothelial cells through Akt-eNOS signaling pathway. Andrology 2015; 3:408-16. [PMID: 25641754 DOI: 10.1111/andr.303] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2014] [Revised: 10/01/2014] [Accepted: 10/03/2014] [Indexed: 12/21/2022]
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Zhao L, Chu CB, Li JF, Yang YT, Niu SQ, Qin W, Hao YG, Dong Q, Guan R, Hu WL, Wang Y. Glycogen synthase kinase-3 reduces acetylcholine level in striatum via disturbing cellular distribution of choline acetyltransferase in cholinergic interneurons in rats. Neuroscience 2013; 255:203-11. [PMID: 24121130 DOI: 10.1016/j.neuroscience.2013.10.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 09/12/2013] [Accepted: 10/01/2013] [Indexed: 12/31/2022]
Abstract
Cholinergic interneurons, which provide the main source of acetylcholine (ACh) in the striatum, control the striatal local circuits and deeply involve in the pathogenesis of neurodegenerative diseases. Glycogen synthase kinase-3 (GSK-3) is a crucial kinase with diverse fundamental functions and accepted that deregulation of GSK-3 activity also plays important roles in diverse neurodegenerative diseases. However, up to now, there is no direct proof indicating whether GSK-3 activation is responsible for cholinergic dysfunction. In the present study, with combined intracerebroventricular injection of Wortmannin and GF-109203X, we activated GSK-3 and demonstrated the increased phosphorylation level of microtubule-associated protein tau and neurofilaments (NFs) in the rat striatum. The activated GSK-3 consequently decreased ACh level in the striatum as a result of the reduction of choline acetyltransferase (ChAT) activity. The alteration of ChAT activity was due to impaired ChAT distribution rather than its expression. Furthermore, we proved that cellular ChAT distribution was dependent on low phosphorylation level of NFs. Nevertheless, the cholinergic dysfunction in the striatum failed to induce significant neuronal number reduction. In summary, our data demonstrates the link between GSK-3 activation and cholinergic dysfunction in the striatum and provided beneficial evidence for the pathogenesis study of relevant neurodegenerative diseases.
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Wang Z, Wang X, Guan R. The study of bone marrow stromal stem cells transplantation via coronary artery after acute myocardial infarction in the dogs. BRITISH HEART JOURNAL 2011. [DOI: 10.1136/heartjnl-2011-300867.404] [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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Xu L, Li Y, Zhang X, Sun H, Sun D, Jia X, Shen C, Zhou J, Ji G, Liu P, Guan R, Yu Y, Jin Y, Bai J, Sun D, Yu J, Fu S. Deletion of
LCE3C
and
LCE3B
genes is associated with psoriasis in a northern Chinese population. Br J Dermatol 2011; 165:882-7. [DOI: 10.1111/j.1365-2133.2011.10485.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Chow WC, Chong R, Guan R, Ho KYL, Leo YS, Loy KL, Lui HF, Ng HS, Siew WF, Teo EK, Yeo T. Ministry of Health clinical practice guidelines: Chronic Hepatitis B Infection. Singapore Med J 2011; 52:307-313. [PMID: 21552794] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The Ministry of Health (MOH) publishes clinical practice guidelines on Chronic Hepatitis B Infection to provide doctors and patients in Singapore with evidence-based guidance on managing important medical conditions. This article reproduces the introduction and executive summary (with recommendations from the guidelines) from the MOH clinical practice guidelines on Chronic Hepatitis B Infection, for the information of readers of the Singapore Medical Journal. Chapters and page numbers mentioned in the reproduced extract refer to the full text of the guidelines, which are available from the Ministry of Health website (http://www.moh.gov.sg/mohcorp/publications.aspx?id=26108). The recommendations should be used with reference to the full text of the guidelines. Following this article are multiple choice questions based on the full text of the guidelines.
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Zhu H, Song X, Jin LJ, Jin LY, Jin P, Guan R, Liu X, Li XQ. Comparison of intra-coronary cell transplantation after myocardial infarction: Autologous skeletal myoblasts versus bone marrow mesenchymal stem cells. J Int Med Res 2009; 37:298-307. [PMID: 19383222 DOI: 10.1177/147323000903700203] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
Cell transplantation promises restoration of cardiac function after myocardial infarction (MI). Comparison of intracoronary cell transplantation with skeletal myoblasts (SMs) versus bone marrow mesenchymal stem cells (BM-MSCs) was carried out in rabbits with MI induced by ligation of the left anterior descending artery. The infarction-affected artery was injected with SMs, BM-MSCs or cell-free medium (control) 24 h post-infarction (n = 15 per group). At baseline, there were no differences in cardiac parameters between the groups. At 4 weeks post-transplantation, left ventricular ejection fraction significantly improved and left ventricular end-diastolic diameter was significantly decreased in the cell-treated groups compared with pre-transplantation and the control group. Engrafted cells were found in all of the cell-treated rabbits. The cell-treated animals had significantly higher numbers of neovessels compared with the control. No significant difference was seen between the SM and BM-MSC groups. In conclusion, intra-coronary transplantation of SMs and BM-MSCs induced neoangiogenesis with comparable enhancements of cardiac performance and reduced cardiac remodelling in a rabbit MI model.
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McCaughan GW, Omata M, Amarapurkar D, Bowden S, Chow WC, Chutaputti A, Dore G, Gane E, Guan R, Hamid SS, Hardikar W, Hui CK, Jafri W, Jia JD, Lai MY, Wei L, Leung N, Piratvisuth T, Sarin S, Sollano J, Tateishi R. Asian Pacific Association for the Study of the Liver consensus statements on the diagnosis, management and treatment of hepatitis C virus infection. J Gastroenterol Hepatol 2007; 22:615-33. [PMID: 17444847 DOI: 10.1111/j.1440-1746.2007.04883.x] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Xiao Z, Guan R, Jiang Y, Li Y. Tensile property of thin microcellular PC sheets prepared by compression molding. EXPRESS POLYM LETT 2007. [DOI: 10.3144/expresspolymlett.2007.33] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Feng X, Ren B, Xie W, Huang Z, Liu J, Guan R, Duan M, Xu J. Influence of hydroxyethyl starch 130/0.4 in pulmonary neutrophil recruitment and acute lung injury during polymicrobial sepsis in rats. Acta Anaesthesiol Scand 2006; 50:1081-8. [PMID: 16987337 DOI: 10.1111/j.1399-6576.2006.01113.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
BACKGROUND Acute lung injury (ALI) is a progressive syndrome associated with significant mortality in sepsis patients. Neutrophils are key cells in the inflammatory response that characterizes ALI. This study was designed to explore the effects of hydroxyethyl starch (HES) 130/0.4 (a novel plasma substitute) on pulmonary neutrophil recruitment and associated ALI in a rat sepsis model induced by cecal ligation and puncture (CLP). METHODS Animals were randomly assigned to six groups [saline control; CLP and saline; CLP and HES (7.5, 15 and 30 ml/kg); and HES control], subjected to CLP and infused with or without HES 130/0.4 4 h after CLP. Six hours later, the pulmonary capillary permeability (PCP), myeloperoxidase (MPO) activity, lung histological changes, tumor necrosis factor-alpha, interleukin-1beta and cytokine-induced neutrophil chemoattractant levels, P-selectin mRNA expression and nuclear factor-kappa B (NF-kappaB) activation were measured. RESULTS Resuscitation with HES 130/0.4 significantly attenuated the CLP-induced increase in PCP, MPO activity, cytokine/chemokine levels, mRNA expression of P-selectin and NF-kappaB activation, all of which are involved in the recruitment of neutrophils. Groups receiving the higher doses of HES 130/0.4 (15 and 30 ml/kg) were more adequately resuscitated. CONCLUSION HES 130/0.4 can inhibit CLP-induced neutrophil recruitment and subsequent ALI by attenuating cytokines/chemokines, adhesion molecule-mediated inflammation and NF-kappaB activation.
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Guo S, Chen NH, Guan R, Feng J, Huang W. Effects of Anti-Bursin Monoclonal Antibody on Immunosuppression in the Duck (Cherry Valley Duck). Poult Sci 2006; 85:258-65. [PMID: 16523625 DOI: 10.1093/ps/85.2.258] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
To study the immunologic function of bursin, we analyzed the effects of anti-bursin monoclonal antibody (mAb) on the immunosuppression in ducks (Cherry Valley duck) by injecting various doses of the anti-bursin mAb into 13-d duck embryos. After hatch, cell-mediated immune activity and humoral responses were studied using lymphocyte proliferation test, tube agglutination test, and indirect enzyme-linked immunosorbent assay to detect anti-Escherichia coli antibodies and antibodies to Riemerella anatipestifer, respectively. Simultaneously, relative weights (BW-adjusted) of bursa of Fabricius (BF), spleen, and thymus were determined. Additionally, the morphology of BF, spleen, and thymus was examined at various ages using conventional histology. Follicle morphology of BF was analyzed by image analysis. The results indicated that anti-bursin mAb markedly decreased duck lymphocyte proliferation, the antibody-producing ability to bacteria, as well as the relative BF weight. Moreover, the anti-bursin mAb hindered the development of BF follicles.
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Tseng W, Guan R, Disterhoft JF, Weiss C. Trace eyeblink conditioning is hippocampally dependent in mice. Hippocampus 2004; 14:58-65. [PMID: 15058483 DOI: 10.1002/hipo.10157] [Citation(s) in RCA: 111] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The goal of this study was to determine whether trace eyeblink conditioning is a hippocampally dependent associative learning task in the mouse. First, we examined trace intervals of 0, 250, and 500 ms to determine a relatively long trace interval that would support eyeblink conditioning in young adult C57BL/6 mice. Mice rapidly acquired conditioned responses (CRs) with a 0-ms trace interval, acquired CRs with a 250-ms trace interval in approximately 2 days (2 sessions per day), and showed little acquisition with a 500-ms trace interval. Control mice were presented randomly unpaired stimuli and failed to show conditioning. We then determined the effect of lesioning dorsal hippocampal neurons on trace eyeblink conditioning. The hippocampus was injected bilaterally with vehicle (phosphate-buffered saline), 0.1% ibotenic acid, or 1% ibotenic acid. The vehicle group showed >60% CRs. The 0.1% group showed significantly fewer CRs (35-45%). The 1% group showed a level of CRs similar to that of the control mice. All the lesioned mice exhibited >60% CRs when subsequently trained with a 0-ms trace interval. A regression analysis indicated that the volume of area CA1 lesioned was more predictive of the behavioral impairment than the lesion volume of either CA3 or dentate gyrus, or even the total lesion volume. We conclude that dorsal hippocampal neurons play a critical role in eyeblink conditioning when a 250-ms trace interval is used with the C57BL/6 mouse, and that this paradigm will be useful for studying behavior and the in vivo and in vitro electrophysiology of hippocampal neurons in normal and transgenic or knockout mice.
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Lim SG, Wai CT, Rajnakova A, Kajiji T, Guan R. Fatal hepatitis B reactivation following discontinuation of nucleoside analogues for chronic hepatitis B. Gut 2002; 51:597-9. [PMID: 12235087 PMCID: PMC1773395 DOI: 10.1136/gut.51.4.597] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Nucleoside analogues such as lamivudine for chronic hepatitis B have an excellent safety profile while patients are on therapy but reactivation flares occur in 19-50% of patients after stopping therapy, some of whom develop liver decompensation. AIMS To describe and report three cases who developed fatal hepatitis B reactivation after stopping nucleoside analogue therapy. SUBJECTS AND RESULTS Three patients are described who developed hepatitis B reactivation and liver decompensation after stopping therapy. One of the three patients was participating in a famciclovir trial and the other two were receiving lamivudine therapy for active hepatitis B infection. All three patients had documented hepatitis B flares, and all had hepatitis B virus DNA detected at that time. All patients developed decompensated liver disease despite one patient having had a prior liver biopsy showing absence of cirrhosis. Reintroduction of lamivudine therapy failed to halt progression of liver decompensation even after hepatitis B virus DNA had been demonstrated to be absent. Sequencing for lamivudine resistant mutants in two cases where serum was available failed to show evidence of mutations associated with lamivudine resistance. CONCLUSION Hepatitis B virus reactivation, leading to decompensation and death, are possible complications of treatment withdrawal and patients should be monitored closely if therapy is ceased.
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Guan R, Wang CG, Wang M, Wang DC. A depressant insect toxin with a novel analgesic effect from scorpion Buthus martensii Karsch. BIOCHIMICA ET BIOPHYSICA ACTA 2001; 1549:9-18. [PMID: 11566364 DOI: 10.1016/s0167-4838(01)00241-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
A new peptide named BmK dITAP3 from scorpion Buthus martensii Karsch (BmK) has been identified to possess a dual bioactivity, a depressant neurotoxicity on insects and an analgesic effect on mice. The bioassays also showed that the peptide was definitely devoid of the neurotoxicity on mammals, which indicated that the analgesic effect of BmK dITAP3 could not be ascribed to the syndromic effects of a mammalian neurotoxicity. BmK dITAP3 exhibited 43.0% inhibition efficiency of the analgesic effect on mice at a dose of 5 mg/kg and the FPU value of 0.5 microg/body (approximately 30 mg) on the fly larvae. The pI value and the molecular mass determined by MALDI-TOF MS for dITAP3 were 6.5 and 6722.7, respectively. Its first 15 N-terminal residues were determined by Edman degradation, based on which the full amino acid sequence was deduced from the cDNA sequence encoding the peptide with 3'-RACE. Circular dichroism and sequence based prediction analyses showed dITAP3 may have a similar molecular scaffold as the most scorpion toxins but with features of the more beta structures and much less of alpha helix. The details of the purification, characterization and sequencing as well as the sequence comparison with other depressant insect toxins and the correlation between the analgesic effect and the insect toxicity will be reported and discussed, respectively.
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Zhang Y, Guan R, Jiang J, Kopchick JJ, Black RA, Baumann G, Frank SJ. Growth hormone (GH)-induced dimerization inhibits phorbol ester-stimulated GH receptor proteolysis. J Biol Chem 2001; 276:24565-73. [PMID: 11309389 DOI: 10.1074/jbc.m101281200] [Citation(s) in RCA: 65] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Growth hormone (GH) initiates its cellular action by properly dimerizing GH receptor (GHR). A substantial fraction of circulating GH is complexed with a high-affinity GH-binding protein (GHBP) that in many species can be generated by GHR proteolysis and shedding of the receptor's ligand-binding extracellular domain. We previously showed that this proteolysis 1) can be acutely promoted by the phorbol ester phorbol 12-myristate 13-acetate (PMA), 2) requires a metalloprotease activity, 3) generates both shed GHBP and a membrane-associated GHR transmembrane/cytoplasmic domain remnant, and 4) results in down-regulation of GHR abundance and GH signaling. Using cell culture model systems, we now explore the effects of GH treatment on inducible GHR proteolysis and GHBP shedding. In human IM-9 lymphocytes, which endogenously express GHRs, and in Chinese hamster ovary cells heterologously expressing wild-type or cytoplasmic domain internal deletion mutant rabbit GHRs, brief exposure to GH inhibited PMA-induced GHR proteolysis (receptor loss and remnant accumulation) by 60-93%. PMA-induced shedding of GHBP from Chinese hamster ovary transfectants was also inhibited by 70% in the presence of GH. The capacity of GH to inhibit inducible GHR cleavage did not rely on JAK2-dependent GH signaling, as evidenced by its continued protection in JAK2-deficient gamma2A rabbit GHR cells. The GH concentration dependence for inhibition of PMA-induced GHR proteolysis paralleled that for its promotion of receptor dimerization (as monitored by formation of GHR disulfide linkage). Unlike GH, the GH antagonist, G120K, which binds to but fails to properly dimerize GHRs, alone did not protect against PMA-induced GHR proteolysis; G120K did, however, antagonize the protective effect of GH. Our data suggest that GH inhibits PMA-induced GHR proteolysis and GHBP shedding by inducing GHR dimerization and that this effect does not appear to be related to GH site 1 binding, GHR internalization, or GHR signaling. The implications of these findings with regard to GH signaling and GHR down-regulation are discussed.
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Leung NW, Lai CL, Chang TT, Guan R, Lee CM, Ng KY, Lim SG, Wu PC, Dent JC, Edmundson S, Condreay LD, Chien RN. Extended lamivudine treatment in patients with chronic hepatitis B enhances hepatitis B e antigen seroconversion rates: results after 3 years of therapy. Hepatology 2001; 33:1527-32. [PMID: 11391543 DOI: 10.1053/jhep.2001.25084] [Citation(s) in RCA: 511] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A study in Chinese patients with chronic hepatitis B showed that treatment with lamivudine for 1 year significantly improves liver histology and enhances hepatitis B e antigen (HBeAg) seroconversion compared with placebo. Fifty-eight patients from this 1-year study have received long-term treatment with lamivudine 100 mg; the outcome of 3 years of lamivudine is reported here. Before treatment, all patients had detectable HBeAg. HBeAg seroconversion (HBeAg-negative, anti-HBe-positive), hepatitis B virus (HBV)-DNA suppression, alanine transaminase (ALT) normalization, emergence of YMDD variant HBV, liver histology, and long-term safety were assessed. After 3 years of continuous treatment with lamivudine 100 mg daily, 40% (23 of 58) of patients achieved HBeAg seroconversion. In patients with baseline serum ALT >2 x upper limit of normal (ULN), the rate of HBeAg seroconversion was 65% (17 of 26). Median serum HBV-DNA concentrations were below the level of detection, and median ALT concentrations were within the normal range throughout 3 years of treatment. YMDD variant HBV emerged in 33 of 58 (57%) patients during the 3 years, of whom 9 (27%) achieved HBeAg seroconversion (6 after emergence of YMDD variant HBV). ALT levels and histologic scores after emergence of YMDD variant HBV did not show major deterioration. Lamivudine was well tolerated during 3 years of therapy. In conclusion, these data in Chinese patients with chronic hepatitis B show enhanced seroconversion rates with extended lamivudine treatment. Up to two thirds of patients with moderately elevated pretreatment ALT achieved HBeAg seroconversion after 3 years of therapy.
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Guan R, Zhang Y, Jiang J, Baumann CA, Black RA, Baumann G, Frank SJ. Phorbol ester- and growth factor-induced growth hormone (GH) receptor proteolysis and GH-binding protein shedding: relationship to GH receptor down-regulation. Endocrinology 2001; 142:1137-47. [PMID: 11181529 DOI: 10.1210/endo.142.3.8030] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
GH signals by interacting with GH receptor (GHR). A substantial fraction of circulating GH complexes with GH-binding protein (GHBP), which corresponds to the GHR extracellular domain. GHBP is generated by 1) alternative splicing of a common GHR precursor messenger RNA to encode secreted GHBP (the source of the vast majority of GHBP in rodents); and 2) proteolysis of the cell-associated GHR with shedding of GHBP (a mechanism operative in rabbits and humans). We previously observed that phorbol ester (PMA)-induced activation of protein kinase C (PKC) causes metalloprotease-mediated GHR proteolysis and GHBP shedding in human IM-9 lymphocytes. We now demonstrate that PMA-induced hydroxamate (IC3)-inhibitable GHR proteolysis and GHBP shedding were also detected in murine 3T3-F442A and 3T3-L1 preadipocytes and in Chinese hamster ovary (CHO) cells stably expressing rabbit GHR (rbGHR), although the degree of GHBP shedding was much smaller for murine GHR than for rabbit or human GHRs. PMA-induced GHR proteolysis in 3T3-F442A, 3T3-L1, and CHO-rbGHR cells was significantly reduced by pretreatment with mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1 inhibitors, suggesting involvement of the mitogen-activated protein kinase pathway in regulating this PKC-dependent effect. In contrast, GHR proteolysis promoted by N-ethylmaleimide, although inhibited by IC3, was unaffected by inhibition of either PKC or mitogen-activated protein kinase/extracellular signal-regulated kinase kinase 1. Thus, different pathways leading to metalloprotease-mediated receptor proteolysis are accessed by PMA vs. N-ethylmaleimide. To determine whether other, possibly more physiologically relevant, stimuli induce GHR proteolysis, we tested effects of platelet-derived growth factor (PDGF) and serum. Treatment of serum-deprived cells with PDGF (in 3T3-F442A cells) or serum (in 3T3-F442A and CHO-rbGHR cells) promoted GHR proteolysis, which was inhibited by IC3. Interestingly, PMA-, PDGF-, and serum-induced GHR proteolysis was associated with substantial decreases in GH-induced activation of Janus kinase-2, which were also prevented by IC3. These findings suggest that inducible metalloprotease-mediated GHR proteolysis constitutes an important mechanism of receptor down-regulation and modulation of GH signaling.
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Merican I, Guan R, Amarapuka D, Alexander MJ, Chutaputti A, Chien RN, Hasnian SS, Leung N, Lesmana L, Phiet PH, Sjalfoellah Noer HM, Sollano J, Sun HS, Xu DZ. Chronic hepatitis B virus infection in Asian countries. J Gastroenterol Hepatol 2000; 15:1356-61. [PMID: 11197043 DOI: 10.1046/j.1440-1746.2000.0150121356.x] [Citation(s) in RCA: 350] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Of the estimated 50 million new cases of hepatitis B virus (HBV) infection diagnosed annually, 5-10% of adults and up to 90% of infants will become chronically infected, 75% of these in Asia where hepatitis B is the leading cause of chronic hepatitis, cirrhosis and hepatocellular carcinoma (HCC). In Indonesia, 4.6% of the population was positive for HBsAg in 1994 and of these, 21% were positive for HBeAg and 73% for anti-HBe; 44% and 45% of Indonesian patients with cirrhosis and HCC, respectively, were HBsAg positive. In the Philippines, there appear to be two types of age-specific HBsAg prevalence, suggesting different modes of transmission. In Thailand, 8-10% of males and 6-8% of females are HBsAg positive, with HBsAg also found in 30% of patients with cirrhosis and 50-75% of those with HCC. In Taiwan, 75-80% of patients with chronic liver disease are HBsAg positive, and HBsAg is found in 34% and 72% of patients with cirrhosis and HCC, respectively. In China, 73% of patients with chronic hepatitis and 78% and 71% of those with cirrhosis and HCC, respectively, are HBsAg positive. In Singapore, the prevalence of HBsAg has dropped since the introduction of HBV vaccination and the HBsAg seroprevalence of unvaccinated individuals over 5 years of age is 4.5%. In Malaysia, 5.24% of healthy volunteers, with a mean age of 34 years, were positive for HBsAg in 1997. In the highly endemic countries in Asia, the majority of infections are contracted postnatally or perinatally. Three phases of chronic HBV infection are recognized: phase 1 patients are HBeAg positive with high levels of virus in the serum and minimal hepatic inflammation; phase 2 patients have intermittent or continuous hepatitis of varying degrees of severity; phase 3 is the inactive phase during which viral concentrations are low and there is minimal inflammatory activity in the liver. In general, patients who clear HBeAg have a better prognosis than patients who remain HBeAg-positive for prolonged periods of time. The outcome after anti-HBe seroconversion depends on the degree of pre-existing liver damage and any subsequent HBV reactivation. Without pre-existing cirrhosis, there may be only slight fibrosis or mild chronic hepatitis, but with pre-existing cirrhosis, further complications may ensue. HBsAg-negative chronic hepatitis B is a phase of chronic HBV infection during which a mutation arises resulting in the inability of the virus to produce HBeAg. Such patients tend to have more severe liver disease and run a more rapidly progressive course. The annual probability of developing cirrhosis varies from 0.1 to 1.0% depending on the duration of HBV replication, the severity of disease and the presence of concomitant infections or drugs. The annual incidence of hepatic decompensation in HBV-related cirrhosis varies from 2 to 10% and in these patients the 5-year survival rate drops dramatically to 14-35%. The annual risk of developing HCC in patients with cirrhosis varies between 1 and 6%; the overall reported annual detection rate of HCC in surveillance studies, which included individuals with chronic hepatitis B and cirrhosis, is 0.8-4.1%. Chronic hepatitis B is not a static disease and the natural history of the disease is affected by both viral and host factors. The prognosis is poor with decompensated cirrhosis and effective treatment options are limited. Prevention of HBV infection thorough vaccination is still, therefore, the best strategy for decreasing the incidence of hepatitis B-associated cirrhosis and HCC.
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Liu B, Guan R, Zhou P, Miao Q, Wang H, Fu D, You B. A distinct mutational spectrum of p53 and K-ras genes in lung cancer of workers with silicosis. J Environ Pathol Toxicol Oncol 2000; 19:1-7. [PMID: 10905501] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/17/2023] Open
Abstract
Crystalline silica was recently classified as a human carcinogen by the International Agency for Research on Cancer (IARC). However, the direct genotoxic effect of silica in humans remains unclear. We examined the p53 and K-ras gene mutations in lung cancer in workers with silicosis (LCWS). DNA was extracted from paraffin-embedded tissues and examined by PCR-RFLP, PCR-SSCP, and DNA sequencing. The mutation frequencies of p53 gene were high, but the mutation distributions in exons and among the histological types of LCWS differed from those of common (i.e., not silicosis-related) lung cancer. Furthermore, no mutations in codon 12 of K-ras gene (predominant in common lung cancer) were found in LCWS. These findings in the mutational spectrum support a carcinogenic effect of silica dust at the DNA molecular level.
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Liaw YF, Leung NW, Chang TT, Guan R, Tai DI, Ng KY, Chien RN, Dent J, Roman L, Edmundson S, Lai CL. Effects of extended lamivudine therapy in Asian patients with chronic hepatitis B. Asia Hepatitis Lamivudine Study Group. Gastroenterology 2000; 119:172-80. [PMID: 10889166 DOI: 10.1053/gast.2000.8559] [Citation(s) in RCA: 500] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
BACKGROUND & AIMS One-year lamivudine therapy significantly suppressed hepatitis B virus (HBV) replication, improved hepatic necroinflammatory activity, and prevented progression of fibrosis. However, the effects of prolonged therapy are unknown. METHODS A total of 334 Asian patients with chronic hepatitis B from a previously reported 1-year study were randomized to receive either lamivudine (100 or 25 mg) or placebo for another year. The effects of treatment on serum HBV-DNA suppression, alanine transaminase (ALT) normalization, and hepatitis B e antigen (HBeAg) seroconversion were measured. The presence of YMDD variant HBV and its effect were also determined. RESULTS A significantly greater proportion of patients achieved sustained HBV-DNA suppression and ALT normalization with 100 mg lamivudine daily for 2 years compared with lamivudine for 1 year followed by placebo for the second year (P<0.001). Daily lamivudine therapy for 2 years was safe and resulted in incremental HBeAg seroconversion from 17% at week 52 to 27% at week 104. HBeAg seroconversion during continued lamivudine therapy increased linearly with increasing pretherapy ALT levels (P< 0.001). Despite the emergence of YMDD mutant in 38% of the patients, they continued to clear serum HBeAg and maintain lower median serum HBV-DNA and ALT levels than baseline values. In contrast, ALT levels increased 8-12 weeks after switching from lamivudine to placebo, but returned to normal once lamivudine treatment was resumed. CONCLUSIONS Treatment with lamivudine for 2 years is both well tolerated and efficacious in patients with chronic hepatitis B.
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Abstract
Interferon-alpha (IFN-alpha) has been the only approved agent for the treatment of chronic hepatitis B in most countries, but this is rapidly changing. It is expensive, associated with frequent and unpleasant side effects, has limited efficacy and is ineffective in subjects with no/mild liver necro-inflammation. Loss of HBsAg and viral replication markers occur 6% and 20%, more often in IFN-treated subjects than controls. The most important factors that will predict favourable response to IFN-alpha therapy are elevated ALT and low serum HBV DNA levels. Chinese patients and children with active liver have similar response rates as Caucasian adults with equivalent ALT levels. Patients with HBeAg negative disease fare less well. Long-term follow up has shown that most IFN responders maintained their response although very few people have complete eradication of HBV.
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Zou N, Lin BY, Duan F, Lee KY, Jin G, Guan R, Yao G, Lefkowitz EJ, Broker TR, Chow LT. The hinge of the human papillomavirus type 11 E2 protein contains major determinants for nuclear localization and nuclear matrix association. J Virol 2000; 74:3761-70. [PMID: 10729151 PMCID: PMC111885 DOI: 10.1128/jvi.74.8.3761-3770.2000] [Citation(s) in RCA: 54] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The E2 protein of papillomaviruses is a site-specific DNA binding nuclear protein. It functions as the primary replication origin recognition protein and assists in the assembly of the preinitiation complex. It also helps regulate transcription from the native viral promoter. The E2 protein consists of an amino-terminal (N) trans-acting domain, a central hinge (H) domain, and a carboxyl-terminal (C) protein dimerization and DNA binding domain. The hinge is highly divergent among papillomaviruses, and little is known about its functions. We fused the enhanced green fluorescent protein (GFP) with the full-length human papillomavirus type 11 (HPV-11) E2 protein and showed that the resultant fusion, called gfpE2, maintained transcription and replication functions of the wild-type protein and formed similar subnuclear foci. Using a series of GFP fusion proteins, we showed that the hinge conferred strong nuclear localization, whereas the N or C domain was present in both cytoplasm and nucleus. Biochemical fractionation demonstrated that the N domain and hinge, but not the C domain, independently associated with the nuclear matrix. Mutational analyses showed that a cluster of basic amino acid residues, which is conserved among many mucosotropic papillomaviruses, was required for efficient nuclear localization and nuclear matrix association. This mutation no longer repressed the HPV-11 upstream regulatory region-controlled reporter expression. However, a very small fraction of this mutant colocalized with E1 in the nucleus, perhaps by a piggyback mechanism, and was able to support transient replication. We propose that the hinge is critical for the diverse regulatory functions of the HPV-11 E2 protein during mRNA transcription and viral DNA replication.
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Li SY, Li RS, Guan R, Ye HQ, Zhu J. Plan-view imaging of oxygen-induced reconstruction on Ag(110) surface. I. The possibility of imaging surface oxygen. JOURNAL OF ELECTRON MICROSCOPY 2000; 49:163-172. [PMID: 10791433 DOI: 10.1093/oxfordjournals.jmicro.a023781] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Surface reconstruction on Ag(110) induced by oxygen adsorption was studied by the plan-view imaging technique of high-resolution electron microscopy (HREM). Systematic multislice simulations were carried out to find the optimal experimental conditions for imaging the surface oxygen. It was found theoretically that there exist a series of characteristic values of objective lens defoci and sample thicknesses under which the surface and the bulk can be imaged clearly and simultaneously. These optimal imaging conditions were used to interpret the experimental micrographs. While the basic features of the surface reconstruction of O/Ag(110) in the HREM images are consistent with those revealed by scanning tunnelling microscopy (STM), there are some new features that have not been reported with STM. These phenomena give some evidence to the existence of subsurface oxygen.
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Liu B, Guan R, Zhou P, Miao Q. [Evidence on the carcinogenicity of silica at DNA level in human]. WEI SHENG YAN JIU = JOURNAL OF HYGIENE RESEARCH 1999; 28:257-8. [PMID: 12712688] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 03/02/2023]
Abstract
The alteration of p53 and K-ras gene in 36 lung cancers of workers occupationally exposed to silica (LCWS) was studied. DNA was extracted from paraffin\|embedded tissues and amplified by PCR. PCR-SS-CP analysis on exons 5, 7 and 8 of p53 gene revealed that 43.8% of mutations were clustered in exon 8 of p53 gene. In ordinary lung cancer, the mutation rate of exon 8 was fluctuated around 20%. The prevalence of mutations was the highest (70%) in small cell lung cancer (SCLC) and the lowest in adenocarcinoma(33%). In our study the mutation rate was high in adenocarcinoma(53.9%) and low in SCLC (30.8%). The K-ras gene of LCWS also revealed a different mutation pattern. Unexpectedly, no mutation was found at codon 12 in 36 LCWS by PCR-RFLP, which is the predominant mutation in K-ras gene in ordinary lung cancer. The point mutation study by DNA sequencing confirmed the absence of codon 12 mutation in K-ras gene in LCWS. The mutations observed in this study were frequently distributed in codons 13 and 15, principally a G-C transversion, instead of G-T transversion in ordinary lung cancer.
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Kang JY, Ho KY, Yeoh KG, Guan R, Wee A, Lee E, Lye WC, Leong SO, Tan CC. Peptic ulcer and gastritis in uraemia, with particular reference to the effect of Helicobacter pylori infection. J Gastroenterol Hepatol 1999; 14:771-8. [PMID: 10482427 DOI: 10.1046/j.1440-1746.1999.01947.x] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIMS To determine: (i) the prevalence of histological gastritis and peptic ulcer; and (ii) the clinical features of peptic ulcer, in patients with end-stage renal failure. METHODS Upper endoscopy was performed by a single observer in 268 patients with end-stage renal failure over a 6-year period. Gastric histology and Helicobacter pylori status were studied in 40 consecutive subjects in whom there were no contraindications for gastric biopsy and who had not used antibacterial drugs in the preceding 4 weeks. As there are only limited data for healthy volunteers in Singapore, 33 age-, sex- and race-matched patients with functional dyspepsia from an earlier drug trial and 18 healthy volunteers who were not age-matched were used as controls. The clinical features of 43 consecutive uraemic patients with peptic ulcer were compared with those of 118 consecutive non-uraemic peptic ulcer patients seen by the same author. RESULTS Among uraemic patients, histological gastritis was less common, compared with healthy volunteers and functional dyspepsia patients. Helicobacter pylori infection as assessed by histology was also less common among uraemic patients compared with functional dyspepsia patients, but the difference was not statistically significant on serological assessment. Uraemic patients with ulcer had an equal sex ratio, in contrast to a male preponderance among peptic ulcer patients with normal renal function. Uraemic patients with ulcer were more likely to be pain-free, to present with haemorrhage, to have multiple ulcers and postbulbar duodenal ulcers, but were less likely to have H. pylori infection. Among uraemic subjects, the prevalence of H. pylori infection was similar whether or not peptic ulcer was present. CONCLUSIONS The prevalence of histological gastritis was lower in uraemic patients when compared with patients with functional dyspepsia and healthy volunteers. Peptic ulcers in uraemic subjects have different clinical characteristics from peptic ulcer in non-uraemic subjects.
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Ji S, Guan R, Frank SJ, Messina JL. Insulin inhibits growth hormone signaling via the growth hormone receptor/JAK2/STAT5B pathway. J Biol Chem 1999; 274:13434-42. [PMID: 10224108 DOI: 10.1074/jbc.274.19.13434] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Insulin is important for maintaining the responsiveness of the liver to growth hormone (GH). Insulin deficiency results in a decrease in liver GH receptor (GHR) expression, which can be reversed by insulin administration. In osteoblasts, continuous insulin treatment decreases the fraction of cellular GHR localized to the plasma membrane. Thus, it is not clear whether hyperinsulinemia results in an enhancement or inhibition of GH action. We asked whether continuous insulin stimulation, similar to what occurs in hyperinsulinemic states, results in GH resistance. Our present studies suggest that insulin treatment of hepatoma cells results in a time-dependent inhibition of acute GH-induced phosphorylation of STAT5B. Whereas total protein levels of JAK2 were not reduced after insulin pretreatment for 16 h, GH-induced JAK2 phosphorylation was inhibited. There was a concomitant decrease in GH binding and a reduction in immunoreactive GHR levels following pretreatment with insulin for 8-24 h. In summary, continuous insulin treatment in rat H4 hepatoma cells reduces GH binding, immunoreactive GHR, GH-induced phosphorylation of JAK2, and GH-induced tyrosine phosphorylation of STAT5B. These findings suggest that hepatic GH resistance may develop when a patient exhibits chronic hyperinsulinemia, a condition often observed in patients with obesity and in the early stage of Type 2 diabetes.
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