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Abstract
It seems politics invades everything. We can rarely think of any activity, any building, any human-to-human interaction and not see some political dimension infiltrating and shaping it. And this very interpretation, in its language of invasion and infiltration, implies that politics’ ubiquity is not necessarily a wanted accomplice in our human world. Nonetheless, its presence is expected, its strategic intentions acknowledged and negotiated.What is interesting is that persona—at least as it has been explored and defined in Persona Studies so far—always has a political dimension. It has been identified as a strategic identity, a form of negotiation of the individual in their foray into a collective world of the social (Marshall and Barbour). Persona is a fabricated reconstruction of the individual that is used to play a role that both helps the individual navigate their presence and interactions with others and helps the collective to position the role of the individual in the social. Persona is imbued with politics at its core.In this issue of Persona Studies, we explore political persona, a characterisation roiled in redundancy if our definitions above are adopted. The essays gathered in this collection debate these definitional affinities, and augment and nuance many other dimensions that help delineate what constitutes political persona. In this introductory essay, we will use the collected work on political persona that is developed in this issue to better define political persona. But before we evaluate and identify the intersections of our contributors’ work, we want to begin our exploration with what makes political persona constitutively different today than in the past. Can we identify through some of the most prominent political personas—Donald Trump, Hillary Clinton, and Bernie Sanders in the United States’ 2016 Presidential campaign, for example—and through a study of a major political event—Brexit in 2016 in the U.K.—whether something has shifted and changed in these cultures?
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Randall K, Henderson N, Reens J, Eckersley S, Nyström AC, South MC, Balendran CA, Böttcher G, Hughes G, Price SA. Claudin-2 Expression Levels in Ulcerative Colitis: Development and Validation of an In-Situ Hybridisation Assay for Therapeutic Studies. PLoS One 2016; 11:e0162076. [PMID: 27598247 PMCID: PMC5012586 DOI: 10.1371/journal.pone.0162076] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2015] [Accepted: 08/17/2016] [Indexed: 12/17/2022] Open
Abstract
Ulcerative colitis is a chronic inflammatory disease affecting the colon and is characterized by epithelial damage and barrier dysfunction. Upregulation of the tight junction protein claudin-2 by cytokines is hypothesized to contribute to the dysregulation of the epithelial barrier. New therapeutic agents which block the action of cytokines are being investigated in patients with ulcerative colitis. In order to understand the potential of these therapies, it is important to have reliable assays that can assess downstream endpoints that reflect drug mechanism of action. The aim of the current study was therefore to establish & validate an assay to reproducibly assess the expression and distribution of claudin-2 in human colon biopsy samples. Initially, the potential to measure claudin-2 protein by immunohistochemistry (IHC) was investigated. To identify suitable reagents to develop an IHC assay, pre-established criteria were used to screen five commercial antibodies by Western blotting, immunofluorescence and immunohistochemistry on claudin-2 positive and negative cells and healthy and ulcerative colitis colon tissue. Despite some of these antibodies specifically detecting claudin-2 using some of these techniques, none of the antibodies showed the expected specific staining pattern in formalin fixed human colon samples. As an alternative method to detect claudin-2 expression and distribution in formalin fixed biopsy sections, an in situ hybridization assay was developed. This assay underwent a novel tiered approach of validation to establish that it was fit-for-purpose, and suitable for clinical deployment. In addition, to understand the possible relationship of claudin-2 in the context of disease severity, expression was compared to the Geboes score. Overall, the microscopical Geboes score correlated with the claudin-2 biomarker score for samples that retained crypt morphology; samples with the highest Geboes score were not specifically distinguished, probably due to crypt destruction. In summary, we have applied a strategy for identifying target-specific antibodies in formalin fixed biopsy samples and highlighted that (published) antibodies may not correctly identify the intended antigen in tissues fixed using this method. Furthermore, we have developed and, for the first time, validated an in situ hybridization assay for detection of claudin-2 mRNA, suitable for use as a supportative method in clinical trials. Using our validated assay, we have demonstrated that increased claudin-2 expression correlates with the severity of ulcerative colitis, where crypt destruction is not seen.
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Henderson N. Narratives of Power and Abuse in Gay Relationships in the Cape Metropole. SOUTH AFRICAN JOURNAL OF PSYCHOLOGY 2012. [DOI: 10.1177/008124631204200304] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This qualitative study, which employed a semi-structured guide with in-depth interviews, examines how gay men construct a gay identity and have relationships within a heteronormative society in the Cape Metropole, South Africa. Data were collected via an MP3 player and each interview was transcribed and analysed using content analysis. The sample distribution included 15 gay men aged between 20 to 46 years. Of these, 12 participants were black (six coloured, three Indian, three African) and three were white. The study examined to what extent unequal power relations and forms of abuse are reported in current practices of gay male relationships. In this article, I will unpack how the intersection of class, age, and other forms of social inequality facilitate abuse before examining how abusive experiences reported emerged out of heteronormative stereotypes, where the ‘masculine’1 partner dominated decision-making and where the ‘feminine’ partner was expected to engage in traditionally ‘feminine roles’. Participants reported surveillance and/or punishment to ensure compliance. In sexual practices, psychological and sexual abuse occurred where normative gender power relations were in operation, leading to experiences of unwanted sexual practices and being infected with HIV. There were further examples where abuse was linked to homophobic and traditional cultural practices. Some of the gay men experiencing abuse in their relationships appeared to resist normative gender power relations, in that the majority of participants found agency to end their relationships in different ways — suggesting that power relations can be interrogated.
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Sacco W, Henderson N. Finding all solutions of nonlinear systems using a hybrid metaheuristic with Fuzzy Clustering Means. Appl Soft Comput 2011. [DOI: 10.1016/j.asoc.2011.05.016] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Ratnayake L, McEwen J, Henderson N, Nathwani D, Phillips G, Brown D, Coia J. Control of an outbreak of diarrhoea in a vascular surgery unit caused by a high-level clindamycin-resistant Clostridium difficile PCR ribotype 106. J Hosp Infect 2011; 79:242-7. [DOI: 10.1016/j.jhin.2011.06.013] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2010] [Accepted: 06/11/2011] [Indexed: 10/17/2022]
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Phan G, Remaut H, Allen W, Geibel S, Lebedev A, Henderson N, Thanassi D, Waksman G. Crystal structure of the usher:chaperone:adhesin subunit complex – insights into pilus assembly mechanism. Acta Crystallogr A 2011. [DOI: 10.1107/s0108767311099533] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
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Duvoix A, Mackay RM, Henderson N, McGreal E, Postle A, Reid K, Clark H. Physiological concentration of calcium inhibits elastase-induced cleavage of a functional recombinant fragment of surfactant protein D. Immunobiology 2011; 216:72-9. [DOI: 10.1016/j.imbio.2010.03.006] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Accepted: 03/08/2010] [Indexed: 10/19/2022]
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Sacco W, Henderson N, Rios-Coelho A, Ali M, Pereira C. Differential evolution algorithms applied to nuclear reactor core design. ANN NUCL ENERGY 2009. [DOI: 10.1016/j.anucene.2009.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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Lowrey GE, Henderson N, Blakey JD, Corne JM, Johnson SR. MMP-9 protein level does not reflect overall MMP activity in the airways of patients with COPD. Respir Med 2008; 102:845-51. [DOI: 10.1016/j.rmed.2008.01.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2007] [Revised: 01/03/2008] [Accepted: 01/14/2008] [Indexed: 11/30/2022]
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Wray RJ, Becker SM, Henderson N, Glik D, Jupka K, Middleton S, Henderson C, Drury A, Mitchell EW. Communicating with the public about emerging health threats: lessons from the Pre-Event Message Development Project. Am J Public Health 2008; 98:2214-22. [PMID: 18382011 DOI: 10.2105/ajph.2006.107102] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
OBJECTIVES We sought to better understand the challenges of communicating with the public about emerging health threats, particularly threats involving toxic chemicals, biological agents, and radioactive materials. METHODS At the request of the Centers for Disease Control and Prevention, we formed an interdisciplinary consortium of investigative teams from 4 schools of public health. Over 2 years, the investigative teams conducted 79 focus group interviews with 884 participants and individual cognitive response interviews with 129 respondents, for a total sample of 1013 individuals. The investigative teams systematically compared their results with other published research in public health, risk communication, and emergency preparedness. RESULTS We found limited public understanding of emerging biological, chemical, and radioactive materials threats and of the differences between them; demand for concrete, accurate, and consistent information about actions needed for protection of self and family; active information seeking from media, local authorities, and selected national sources; and areas in which current emergency messaging can be improved. CONCLUSIONS The public will respond to a threat situation by seeking protective information and taking self-protective action, underlining the critical role of effective communication in public health emergencies.
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Henderson N, Shefer T. Practices of Power and Abuse in Gay Male Relationships: An Exploratory Case Study of a Young, Isixhosa-Speaking Man in the Western Cape, South Africa. SOUTH AFRICAN JOURNAL OF PSYCHOLOGY 2008. [DOI: 10.1177/008124630803800101] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
This article constitutes a single case study of snapshots of the life of a young, gay isiXhosa-speaking man, and his narrative on relationships. The case study is a part of a broader study exploring gay male relationships with a particular focus on the dynamics of control, power, and abuse. The broader literature on gay relationships, both internationally and locally, highlights the pervasiveness of heteropatriarchal stereotypical constructions in many gay relationships, believed to facilitate unequal power relations (as they do in heterosexual relationships), but also foregrounds a more ‘flexible’ approach to constructing masculinities and sexual roles among gay men. The article highlights the experience of performances of sexuality and relationship that mirror heterosexual traditional roles, with accompanying power inequalities, as well as a shift to alternative, more flexible and possibly more equitable relationships. It is also argued that homophobia, emerging in multiple sites and including internalised homophobia, plays a powerful role in the reproduction of inequality and abusive practices within gay male relationships. The article interrogates some of the local contexts of homophobia in contemporary South Africa and the way in which the participant's experiences, within and outside his relationships, reflect a corroding of self-confidence and sense of power. It also explores the challenges faced in constructing equitable intimate relationships within a society that still adheres to hegemonic practices of masculinity and heteronormative models of relation.
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Henderson N. Aesthetic options. Br Dent J 2008; 204:356. [DOI: 10.1038/sj.bdj.2008.261] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Hardy KJ, Gossain S, Henderson N, Drugan C, Oppenheim BA, Gao F, Hawkey PM. Rapid recontamination with MRSA of the environment of an intensive care unit after decontamination with hydrogen peroxide vapour. J Hosp Infect 2007; 66:360-8. [PMID: 17655975 DOI: 10.1016/j.jhin.2007.05.009] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2007] [Accepted: 05/04/2007] [Indexed: 10/23/2022]
Abstract
Meticillin-resistant Staphylococcus aureus (MRSA) persists in the hospital environment and conventional cleaning procedures do not necessarily eliminate contamination. A prospective study was conducted on an intensive care unit to establish the level of environmental contamination with MRSA, assess the effectiveness of hydrogen peroxide vapour (HPV) decontamination and determine the rate of environmental recontamination. MRSA was isolated from 11.2% of environmental sites in the three months preceding the use of HPV and epidemiological typing revealed that the types circulating within the environment were similar to those colonising patients. After patient discharge and terminal cleaning using conventional methods, MRSA was isolated from five sites (17.2%). After HPV decontamination but before the readmission of patients, MRSA was not isolated from the environment. Twenty-four hours after readmitting patients, including two colonized with MRSA, the organism was isolated from five sites. The strains were indistinguishable from a strain with which a patient was colonized but were not all confined to the immediate vicinity of the colonized patient. In the eight weeks after the use of HPV, the environment was sampled on a weekly basis and MRSA was isolated from 16.3% sites. Hydrogen peroxide vapour is effective in eliminating bacteria from the environment but the rapid rate of recontamination suggests that it is not an effective means of maintaining low levels of environmental contamination in an open-plan intensive care unit.
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Harvie P, Haroon M, Henderson N, El-Guindi M. Fracture of the hydroxyapatite-ceramic-coated JRI-Furlong femoral component. ACTA ACUST UNITED AC 2007; 89:742-5. [PMID: 17613497 DOI: 10.1302/0301-620x.89b6.18680] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
We describe three cases of fracture of the titanium JRI-Furlong hydroxyapatite-ceramic (HAC)-coated femoral component. We have examined previous case reports of failure of this stem and conclude that fracture may occur in two places, namely at the neck-shoulder junction and at the conical-distal cylindrical junction. These breakages are the result of fatigue in a metallurgically-proven normal femoral component. All the cases of failure of the femoral component have occurred in patients with a body mass index of more than 25 in whom a small component, either size 9 or 10, had been used. In patients with a body mass index above normal size 9 components should be avoided and the femoral canal should be reamed sufficiently to accept a large femoral component to ensure that there is adequate metaphyseal fixation.
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Henderson N, Markwick LJ, Elshaw SR, Freyer AM, Knox AJ, Johnson SR. Collagen I and thrombin activate MMP-2 by MMP-14-dependent and -independent pathways: implications for airway smooth muscle migration. Am J Physiol Lung Cell Mol Physiol 2006; 292:L1030-8. [PMID: 17189319 DOI: 10.1152/ajplung.00317.2006] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Increased proinflammatory mediators and ECM deposition are key features of the airways in asthma. Matrix metalloproteinases (MMPs) are produced by airway smooth muscle (ASM) cells and have multiple roles in inflammation and tissue remodeling. We hypothesized that components of the asthmatic airway would stimulate MMP production and activation by ASM and contribute to airway remodeling. We measured human ASM-derived MMP mRNA, protein, and activity by real-time RT-PCR, zymography, Western blotting, and MMP activity assay. Collagen I and thrombin caused a synergistic increase in MMP-2 protein and total MMP activity but paradoxically decreased MMP-2 mRNA. Additionally, collagen I activated MMP-2 in culture supernatants independent of the cell surface. Together, collagen I and thrombin strongly enhanced MMP-14 mRNA and protein but had no effect individually, suggesting increased MMP-14, the activating protease for MMP-2, may be partially responsible for MMP-2 activation. Furthermore, collagen I reduced tissue inhibitor of metalloproteinase-2 protein (TIMP-2). We examined the role of MMPs in functions of ASM related to airway remodeling and found migration and proliferation were MMP dependent, whereas adhesion and apoptosis were not. Ilomastat inhibited migration by 25%, which was also inhibited by TIMPs 1-4 and increased by the MMP-2 activator thrombin. These in vitro findings suggest that the environment within the airways of patients with asthma enhances MMP-2 and -14 protein and activity by a complex interaction of transcriptional and posttranscriptional mechanisms, which may contribute to ASM migration.
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Platt GM, Henderson N, de Medeiros JL. Determination of critical conditions for the esterification of acetic acid with ethanol in the presence of carbon dioxide. BRAZILIAN JOURNAL OF CHEMICAL ENGINEERING 2006. [DOI: 10.1590/s0104-66322006000300009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Capell HA, Madhok R, Porter DR, Munro RAL, McInnes IB, Hunter JA, Steven M, Zoma A, Morrison E, Sambrook M, Wui Poon F, Hampson R, McDonald F, Tierney A, Henderson N, Ford I. Combination therapy with sulfasalazine and methotrexate is more effective than either drug alone in patients with rheumatoid arthritis with a suboptimal response to sulfasalazine: results from the double-blind placebo-controlled MASCOT study. Ann Rheum Dis 2006; 66:235-41. [PMID: 16926184 PMCID: PMC1798490 DOI: 10.1136/ard.2006.057133] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Optimal use of disease-modifying antirheumatic drugs (DMARDs) in rheumatoid arthritis is vital if progression of disease is to be reduced. Methotrexate (MTX) and sulfasalazine (SASP) are widely used inexpensive DMARDs, recently often combined despite no firm evidence of benefit from previous studies. AIM To establish whether a combination of SASP and MTX is superior to either drug alone in patients with rheumatoid arthritis with a suboptimal response to 6 months of SASP. METHODS A randomised controlled study of step-up DMARD treatment in early rheumatoid arthritis. In phase I, 687 patients received SASP for 6 months. Those with a disease activity score (DAS) > or =2.4 were offered additional treatment in phase II (SASP alone, MTX alone or a combination of the two). The primary outcome measure was change in DAS. RESULTS At 6 months, 191 (28%) patients had a DAS <2.4, 123 (18%) were eligible but did not wish to enter phase II, 130 (19%) stopped SASP because of reversible adverse events and 165 (24%) entered phase II. DAS at 18 months was significantly lower in those who received combination treatment compared with those who received either SASP or MTX: monotherapy arms did not differ. Improvement in European League Against Rheumatism and American College of Rheumatology 20, 50 and 70 scores favoured combination therapy. CONCLUSIONS In this "true-to-life" study, an inexpensive combination of DMARDs proved more effective than monotherapy in patients with rheumatoid arthritis with a suboptimal response to SASP. There was no increase in toxicity. These results provide an evidence base for the use of this combination as a component of tight control strategies.
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Burns CM, Henderson N. The mineral constituents of bone: The influence of age on the mineral constituents of bones from kittens and pups. Biochem J 2006; 30:1207-14. [PMID: 16746143 PMCID: PMC1263165 DOI: 10.1042/bj0301207] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Burns CM, Henderson N. Changes in growth and water content of the bones of newly born pups and kittens. Biochem J 2006; 30:1202-6. [PMID: 16746142 PMCID: PMC1263164 DOI: 10.1042/bj0301202] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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Polignano F, Henderson N, Alishahi SM, Zito A. Laparoscopic colectomy for cancer and adequate lymphadenectomy. Surg Endosc 2006; 20:996-7. [PMID: 16739001 DOI: 10.1007/s00464-005-0555-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2005] [Accepted: 12/21/2005] [Indexed: 10/24/2022]
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Constandinou C, Henderson N, Iredale JP. Modeling liver fibrosis in rodents. METHODS IN MOLECULAR MEDICINE 2005. [PMID: 16118456 DOI: 10.1385/1-59259-940-0: 237] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Animal models of hepatic fibrosis provide a means to study the cell and molecular mediators of fibrosis in a serial manner during both progression and recovery. Several approaches to induction of fibrosis have been described. Of these, CCl(4) intoxication in rats and mice is probably the most widely studied. In addition, the CCl(4) model is the best characterized with respect to histological, biochemical, cell, and molecular changes associated with the development of fibrosis. CCl(4) can be given intraperitoneally or by oral gavage; it induces zone III necrosis and hepatocyte apoptosis with associated hepatic stellate cell activation and tissue fibrosis. With repetitive dosing CCl(4) can be used to induce bridging hepatic fibrosis (4 wk of twice-weekly dosing), cirrhosis (8 wk of twice-weekly dosing) and advanced micronodular cirrhosis (12 wk of twice-weekly dosing). In addition, for each of these models spontaneous recovery from fibrosis can be studied after cessation of dosing. Mechanistic studies using gene knockout and transgenic animals can also be established using CCl(4). Together these models have provided unparalleled insights into the mechanisms underlying hepatic fibrosis.
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Constandinou C, Henderson N, Iredale JP. Modeling liver fibrosis in rodents. METHODS IN MOLECULAR MEDICINE 2005; 117:237-50. [PMID: 16118456 DOI: 10.1385/1-59259-940-0:237] [Citation(s) in RCA: 97] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Animal models of hepatic fibrosis provide a means to study the cell and molecular mediators of fibrosis in a serial manner during both progression and recovery. Several approaches to induction of fibrosis have been described. Of these, CCl(4) intoxication in rats and mice is probably the most widely studied. In addition, the CCl(4) model is the best characterized with respect to histological, biochemical, cell, and molecular changes associated with the development of fibrosis. CCl(4) can be given intraperitoneally or by oral gavage; it induces zone III necrosis and hepatocyte apoptosis with associated hepatic stellate cell activation and tissue fibrosis. With repetitive dosing CCl(4) can be used to induce bridging hepatic fibrosis (4 wk of twice-weekly dosing), cirrhosis (8 wk of twice-weekly dosing) and advanced micronodular cirrhosis (12 wk of twice-weekly dosing). In addition, for each of these models spontaneous recovery from fibrosis can be studied after cessation of dosing. Mechanistic studies using gene knockout and transgenic animals can also be established using CCl(4). Together these models have provided unparalleled insights into the mechanisms underlying hepatic fibrosis.
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Elshaw SR, Henderson N, Knox AJ, Watson SA, Buttle DJ, Johnson SR. Matrix metalloproteinase expression and activity in human airway smooth muscle cells. Br J Pharmacol 2004; 142:1318-24. [PMID: 15265805 PMCID: PMC1575191 DOI: 10.1038/sj.bjp.0705883] [Citation(s) in RCA: 49] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Airway remodelling is a feature of chronic asthma comprising smooth muscle hypertrophy and deposition of extracellular matrix (ECM) proteins. Matrix metalloproteinases (MMPs) breakdown ECM, are involved in tissue remodelling and have been implicated in airway remodelling. Although mesenchymal cells are an important source of MMPs, little data are available on airway smooth muscle (ASM) derived MMPs. We therefore investigated MMP and tissue inhibitor of metalloproteinase (TIMP) production and activity in human ASM cells. MMPs and TIMPs were examined using quantitative real-time RT-PCR, Western blotting, zymography and a quench fluorescence (QF) assay of total MMP activity. The most abundant MMPs were pro-MMP-2, pro- MMP-3, active MMP-3 and MT1-MMP. TIMP-1 and TIMP-2 expression was low in cell lysates but high in conditioned medium. High TIMP secretion was confirmed by the ability of ASM-conditioned medium to inhibit recombinant MMP-2 in a QF assay. Thrombin increased MMP activity by activation of pro-MMP-2 independent of the conventional smooth muscle thrombin receptors PAR 1 and 4. In conclusion, ASM cells express pro-MMP-2, pro and active MMP-3, MMP-9 and MT1-MMP. Unstimulated cells secrete excess TIMP 1 and 2, preventing proteolytic activity. MMP-2 can be activated by thrombin which may contribute to airway remodelling.
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MESH Headings
- Cell Line, Tumor
- Cells, Cultured
- Culture Media, Conditioned/pharmacology
- Dose-Response Relationship, Drug
- Gene Expression Regulation, Enzymologic/drug effects
- Gene Expression Regulation, Enzymologic/physiology
- Humans
- Matrix Metalloproteinase Inhibitors
- Matrix Metalloproteinases/biosynthesis
- Matrix Metalloproteinases/genetics
- Myocytes, Smooth Muscle/drug effects
- Myocytes, Smooth Muscle/enzymology
- RNA, Messenger/biosynthesis
- RNA, Messenger/genetics
- Trachea/drug effects
- Trachea/enzymology
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Frampton GA, Hannah DR, Henderson N, Katz RB, Smith IH, Tremayne N, Watson RJ, Woollam I. Approaches to a Scaleable Synthesis of CH8757: A Potent Inhibitor of Matrix Metalloproteinases. Org Process Res Dev 2004. [DOI: 10.1021/op049954q] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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