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Colm O'Morain

Bio: Colm O'Morain is an academic researcher from Trinity College, Dublin. The author has contributed to research in topics: Helicobacter pylori & Inflammatory bowel disease. The author has an hindex of 76, co-authored 417 publications receiving 33408 citations. Previous affiliations of Colm O'Morain include Oklahoma State University Center for Health Sciences & Tallaght Hospital.


Papers
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Journal ArticleDOI
31 May 2001-Nature
TL;DR: It is suggested that the NOD2 gene product confers susceptibility to Crohn's disease by altering the recognition of these components and/or by over-activating NF-kB in monocytes, thus documenting a molecular model for the pathogenic mechanism of Crohn’s disease that can now be further investigated.
Abstract: Crohn's disease and ulcerative colitis, the two main types of chronic inflammatory bowel disease, are multifactorial conditions of unknown aetiology A susceptibility locus for Crohn's disease has been mapped to chromosome 16 Here we have used a positional-cloning strategy, based on linkage analysis followed by linkage disequilibrium mapping, to identify three independent associations for Crohn's disease: a frameshift variant and two missense variants of NOD2, encoding a member of the Apaf-1/Ced-4 superfamily of apoptosis regulators that is expressed in monocytes These NOD2 variants alter the structure of either the leucine-rich repeat domain of the protein or the adjacent region NOD2 activates nuclear factor NF-kB; this activating function is regulated by the carboxy-terminal leucine-rich repeat domain, which has an inhibitory role and also acts as an intracellular receptor for components of microbial pathogens These observations suggest that the NOD2 gene product confers susceptibility to Crohn's disease by altering the recognition of these components and/or by over-activating NF-kB in monocytes, thus documenting a molecular model for the pathogenic mechanism of Crohn's disease that can now be further investigated

5,388 citations

Journal ArticleDOI
01 Jun 2007-Gut
TL;DR: H pylori eradication is less effective than proton pump inhibitor (PPI) treatment in preventing ulcer recurrence in long term NSAID users and a test and treat strategy using a non-invasive test is recommended in adult patients with persistent dyspepsia under the age of 45.
Abstract: Background: Guidelines on the management of Helicobacter pylori , which cover indications for management and treatment strategies, were produced in 2000. Aims: To update the guidelines at the European Helicobacter Study Group (EHSG) Third Maastricht Consensus Conference, with emphasis on the potential of H pylori eradication for the prevention of gastric cancer. Results: Eradication of H pylori infection is recommended in ( a ) patients with gastroduodenal diseases such as peptic ulcer disease and low grade gastric, mucosa associated lymphoid tissue (MALT) lymphoma; ( b ) patients with atrophic gastritis; ( c ) first degree relatives of patients with gastric cancer; ( d ) patients with unexplained iron deficiency anaemia; and ( e ) patients with chronic idiopathic thrombocytopenic purpura. Recurrent abdominal pain in children is not an indication for a “test and treat” strategy if other causes are excluded. Eradication of H pylori infection ( a ) does not cause gastro-oesophageal reflux disease (GORD) or exacerbate GORD, and ( b ) may prevent peptic ulcer in patients who are naive users of non-steroidal anti-inflammatory drugs (NSAIDs). H pylori eradication is less effective than proton pump inhibitor (PPI) treatment in preventing ulcer recurrence in long term NSAID users. In primary care a test and treat strategy using a non-invasive test is recommended in adult patients with persistent dyspepsia under the age of 45. The urea breath test, stool antigen tests, and serological kits with a high accuracy are non-invasive tests which should be used for the diagnosis of H pylori infection. Triple therapy using a PPI with clarithromycin and amoxicillin or metronidazole given twice daily remains the recommended first choice treatment. Bismuth-containing quadruple therapy, if available, is also a first choice treatment option. Rescue treatment should be based on antimicrobial susceptibility. Conclusion: The global burden of gastric cancer is considerable but varies geographically. Eradication of H pylori infection has the potential to reduce the risk of gastric cancer development.

2,266 citations

Journal ArticleDOI
01 Jan 2017-Gut
TL;DR: This fifth edition of the Maastricht Consensus Report describes how experts from 24 countries examined new data related to H. pylori infection in the various clinical scenarios and provided recommendations on the basis of the best available evidence and relevance.
Abstract: Important progress has been made in the management of Helicobacter pylori infection and in this fifth edition of the Maastricht Consensus Report, key aspects related to the clinical role of H. pylori were re-evaluated in 2015. In the Maastricht V/Florence Consensus Conference, 43 experts from 24 countries examined new data related to H. pylori in five subdivided workshops: (1) Indications/Associations, (2) Diagnosis, (3) Treatment, (4) Prevention/Public Health, (5) H. pylori and the Gastric Microbiota. The results of the individual workshops were presented to a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in the various clinical scenarios.

2,219 citations

Journal ArticleDOI
TL;DR: This paper is the second in a series of three publications relating to the European evidence-based consensus on the diagnosis and management of Crohn's disease and concerns the management of active disease, maintenance of medically induced remission and surgery.
Abstract: This paper is the second in a series of three publications relating to the European evidence-based consensus on the diagnosis and management of Crohn's disease and concerns the management of active disease, maintenance of medically induced remission and surgery. The aims and methods of the ECCO Consensus, as well as sections on diagnosis and classification are covered in the first paper [van Assche et al. JCC 2009a]. The final paper covers post-operative recurrence, fistulating disease, the management of paediatric and adolescent IBD, pregnancy, psychosomatics, extraintestinal manifestations and complementary or alternative therapy for Crohn's disease [Van Assche et al JCC 2009b]. #### Principal changes with respect to the 2006 ECCO guidelines The early use of azathioprine/mercaptopurine or methotrexate in combination with steroids is an appropriate option in moderately active localised ileocaecal CD. Anti-TNF therapy should be considered as an alternative for patients with objective evidence of active disease who have previously been steroid-refractory, steroid-dependent, or steroid-intolerant (based on Statement 5B). For those patients with severely active localised ileocaecal Crohn's disease and objective evidence of active disease who have relapsed, anti-TNF therapy with or without an immunomodulator is an appropriate option [EL1a, RG B for infliximab]. For some patients who have infrequently relapsing disease, restarting steroids with an immunomodulator may be appropriate (based on Statement 5C). All currently available anti-TNF therapies appear to have generally similar efficacy and adverse-event profiles for inflammatory (‘luminal’) Crohn's disease, so the choice depends on availability, route of delivery, patient preference, cost and national guidelines \[EL5, RG D\] (Statement 5I). Patients receiving azathioprine or mercaptopurine who relapse should be evaluated for adherence to therapy and have their dose optimised. Changing their maintenance therapy to methotrexate [EL1b RG B] or anti-TNF therapy [EL1a RGB] should be considered. Surgery should always be considered as an option in localised disease [EL4, …

1,477 citations


Cited by
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Journal ArticleDOI
Paul Burton1, David Clayton2, Lon R. Cardon, Nicholas John Craddock3  +192 moreInstitutions (4)
07 Jun 2007-Nature
TL;DR: This study has demonstrated that careful use of a shared control group represents a safe and effective approach to GWA analyses of multiple disease phenotypes; generated a genome-wide genotype database for future studies of common diseases in the British population; and shown that, provided individuals with non-European ancestry are excluded, the extent of population stratification in theBritish population is generally modest.
Abstract: There is increasing evidence that genome-wide association ( GWA) studies represent a powerful approach to the identification of genes involved in common human diseases. We describe a joint GWA study ( using the Affymetrix GeneChip 500K Mapping Array Set) undertaken in the British population, which has examined similar to 2,000 individuals for each of 7 major diseases and a shared set of similar to 3,000 controls. Case-control comparisons identified 24 independent association signals at P < 5 X 10(-7): 1 in bipolar disorder, 1 in coronary artery disease, 9 in Crohn's disease, 3 in rheumatoid arthritis, 7 in type 1 diabetes and 3 in type 2 diabetes. On the basis of prior findings and replication studies thus-far completed, almost all of these signals reflect genuine susceptibility effects. We observed association at many previously identified loci, and found compelling evidence that some loci confer risk for more than one of the diseases studied. Across all diseases, we identified a large number of further signals ( including 58 loci with single-point P values between 10(-5) and 5 X 10(-7)) likely to yield additional susceptibility loci. The importance of appropriately large samples was confirmed by the modest effect sizes observed at most loci identified. This study thus represents a thorough validation of the GWA approach. It has also demonstrated that careful use of a shared control group represents a safe and effective approach to GWA analyses of multiple disease phenotypes; has generated a genome-wide genotype database for future studies of common diseases in the British population; and shown that, provided individuals with non-European ancestry are excluded, the extent of population stratification in the British population is generally modest. Our findings offer new avenues for exploring the pathophysiology of these important disorders. We anticipate that our data, results and software, which will be widely available to other investigators, will provide a powerful resource for human genetics research.

9,244 citations

Journal ArticleDOI
TL;DR: Microbial recognition by Toll-like receptors helps to direct adaptive immune responses to antigens derived from microbial pathogens to distinguish infectious nonself from noninfectious self.
Abstract: ▪ Abstract The innate immune system is a universal and ancient form of host defense against infection. Innate immune recognition relies on a limited number of germline-encoded receptors. These receptors evolved to recognize conserved products of microbial metabolism produced by microbial pathogens, but not by the host. Recognition of these molecular structures allows the immune system to distinguish infectious nonself from noninfectious self. Toll-like receptors play a major role in pathogen recognition and initiation of inflammatory and immune responses. Stimulation of Toll-like receptors by microbial products leads to the activation of signaling pathways that result in the induction of antimicrobial genes and inflammatory cytokines. In addition, stimulation of Toll-like receptors triggers dendritic cell maturation and results in the induction of costimulatory molecules and increased antigen-presenting capacity. Thus, microbial recognition by Toll-like receptors helps to direct adaptive immune responses ...

8,041 citations

Journal ArticleDOI
01 Nov 2012-Nature
TL;DR: It is shown that evolutionary conservation and coding consequence are key determinants of the strength of purifying selection, that rare-variant load varies substantially across biological pathways, and that each individual contains hundreds of rare non-coding variants at conserved sites, such as motif-disrupting changes in transcription-factor-binding sites.
Abstract: By characterizing the geographic and functional spectrum of human genetic variation, the 1000 Genomes Project aims to build a resource to help to understand the genetic contribution to disease. Here we describe the genomes of 1,092 individuals from 14 populations, constructed using a combination of low-coverage whole-genome and exome sequencing. By developing methods to integrate information across several algorithms and diverse data sources, we provide a validated haplotype map of 38 million single nucleotide polymorphisms, 1.4 million short insertions and deletions, and more than 14,000 larger deletions. We show that individuals from different populations carry different profiles of rare and common variants, and that low-frequency variants show substantial geographic differentiation, which is further increased by the action of purifying selection. We show that evolutionary conservation and coding consequence are key determinants of the strength of purifying selection, that rare-variant load varies substantially across biological pathways, and that each individual contains hundreds of rare non-coding variants at conserved sites, such as motif-disrupting changes in transcription-factor-binding sites. This resource, which captures up to 98% of accessible single nucleotide polymorphisms at a frequency of 1% in related populations, enables analysis of common and low-frequency variants in individuals from diverse, including admixed, populations.

7,710 citations

Journal ArticleDOI
John W. Belmont1, Paul Hardenbol, Thomas D. Willis, Fuli Yu1, Huanming Yang2, Lan Yang Ch'Ang, Wei Huang3, Bin Liu2, Yan Shen3, Paul K.H. Tam4, Lap-Chee Tsui4, Mary M.Y. Waye5, Jeffrey Tze Fei Wong6, Changqing Zeng2, Qingrun Zhang2, Mark S. Chee7, Luana Galver7, Semyon Kruglyak7, Sarah S. Murray7, Arnold Oliphant7, Alexandre Montpetit8, Fanny Chagnon8, Vincent Ferretti8, Martin Leboeuf8, Michael S. Phillips8, Andrei Verner8, Shenghui Duan9, Denise L. Lind10, Raymond D. Miller9, John P. Rice9, Nancy L. Saccone9, Patricia Taillon-Miller9, Ming Xiao10, Akihiro Sekine, Koki Sorimachi, Yoichi Tanaka, Tatsuhiko Tsunoda, Eiji Yoshino, David R. Bentley11, Sarah E. Hunt11, Don Powell11, Houcan Zhang12, Ichiro Matsuda13, Yoshimitsu Fukushima14, Darryl Macer15, Eiko Suda15, Charles N. Rotimi16, Clement Adebamowo17, Toyin Aniagwu17, Patricia A. Marshall18, Olayemi Matthew17, Chibuzor Nkwodimmah17, Charmaine D.M. Royal16, Mark Leppert19, Missy Dixon19, Fiona Cunningham20, Ardavan Kanani20, Gudmundur A. Thorisson20, Peter E. Chen21, David J. Cutler21, Carl S. Kashuk21, Peter Donnelly22, Jonathan Marchini22, Gilean McVean22, Simon Myers22, Lon R. Cardon22, Andrew P. Morris22, Bruce S. Weir23, James C. Mullikin24, Michael Feolo24, Mark J. Daly25, Renzong Qiu26, Alastair Kent, Georgia M. Dunston16, Kazuto Kato27, Norio Niikawa28, Jessica Watkin29, Richard A. Gibbs1, Erica Sodergren1, George M. Weinstock1, Richard K. Wilson9, Lucinda Fulton9, Jane Rogers11, Bruce W. Birren25, Hua Han2, Hongguang Wang, Martin Godbout30, John C. Wallenburg8, Paul L'Archevêque, Guy Bellemare, Kazuo Todani, Takashi Fujita, Satoshi Tanaka, Arthur L. Holden, Francis S. Collins24, Lisa D. Brooks24, Jean E. McEwen24, Mark S. Guyer24, Elke Jordan31, Jane Peterson24, Jack Spiegel24, Lawrence M. Sung32, Lynn F. Zacharia24, Karen Kennedy29, Michael Dunn29, Richard Seabrook29, Mark Shillito, Barbara Skene29, John Stewart29, David Valle21, Ellen Wright Clayton33, Lynn B. Jorde19, Aravinda Chakravarti21, Mildred K. Cho34, Troy Duster35, Troy Duster36, Morris W. Foster37, Maria Jasperse38, Bartha Maria Knoppers39, Pui-Yan Kwok10, Julio Licinio40, Jeffrey C. Long41, Pilar N. Ossorio42, Vivian Ota Wang33, Charles N. Rotimi16, Patricia Spallone43, Patricia Spallone29, Sharon F. Terry44, Eric S. Lander25, Eric H. Lai45, Deborah A. Nickerson46, Gonçalo R. Abecasis41, David Altshuler47, Michael Boehnke41, Panos Deloukas11, Julie A. Douglas41, Stacey Gabriel25, Richard R. Hudson48, Thomas J. Hudson8, Leonid Kruglyak49, Yusuke Nakamura50, Robert L. Nussbaum24, Stephen F. Schaffner25, Stephen T. Sherry24, Lincoln Stein20, Toshihiro Tanaka 
18 Dec 2003-Nature
TL;DR: The HapMap will allow the discovery of sequence variants that affect common disease, will facilitate development of diagnostic tools, and will enhance the ability to choose targets for therapeutic intervention.
Abstract: The goal of the International HapMap Project is to determine the common patterns of DNA sequence variation in the human genome and to make this information freely available in the public domain. An international consortium is developing a map of these patterns across the genome by determining the genotypes of one million or more sequence variants, their frequencies and the degree of association between them, in DNA samples from populations with ancestry from parts of Africa, Asia and Europe. The HapMap will allow the discovery of sequence variants that affect common disease, will facilitate development of diagnostic tools, and will enhance our ability to choose targets for therapeutic intervention.

5,926 citations

Journal ArticleDOI
TL;DR: This unit discusses mammalian Toll receptors (TLR1‐10) that have an essential role in the innate immune recognition of microorganisms and are discussed are TLR‐mediated signaling pathways and antibodies that are available to detect specific TLRs.
Abstract: The innate immune system in drosophila and mammals senses the invasion of microorganisms using the family of Toll receptors, stimulation of which initiates a range of host defense mechanisms. In drosophila antimicrobial responses rely on two signaling pathways: the Toll pathway and the IMD pathway. In mammals there are at least 10 members of the Toll-like receptor (TLR) family that recognize specific components conserved among microorganisms. Activation of the TLRs leads not only to the induction of inflammatory responses but also to the development of antigen-specific adaptive immunity. The TLR-induced inflammatory response is dependent on a common signaling pathway that is mediated by the adaptor molecule MyD88. However, there is evidence for additional pathways that mediate TLR ligand-specific biological responses.

5,915 citations