title: Evidence of an inflammatory pathologic condition in "normal" appendices following emergency appendectomy.
abstract: BACKGROUND
  Appendices removed from patients with suspected appendicitis often appear normal on histologic examination.
  
  
  OBJECTIVE
  To study appendix specimens for the expression of inflammatory markers as an indicator of presence of an inflammatory response in this subgroup of patients.
  
  
  METHODS
  Cyclooxygenase 1 and 2, prostaglandin E(2), inducible nitric oxide synthase, and major histocompatibility complex class II were investigated by immunofluorohistochemistry using confocal laser microscopy in 15 acutely inflamed appendix specimens, 39 histologically classified "normal" appendices, and 11 negative control specimens.
  
  
  RESULTS
  Strong expressions of all the inflammatory mediators were found in the mucosa of inflamed appendices, in approximately 50% of histologically normal appendices from patients with a clinical diagnosis of appendicitis, and in none of the normal control specimens.
  
  
  CONCLUSIONS
  This study confirms the existence of a subgroup of appendicitis within the so-called histologically normal appendices in which evidence of an inflammatory pathologic condition is only obvious at a molecular level. The initiating signal for this and all other forms of clinical appendicitis still remains elusive.
authors.affiliation: Children's Research Centre, Our Lady's Hospital for Sick Children, Dublin, Ireland.
authors.forename: L
authors.initials: L
authors.lastname: Nemeth
authors.forename: D J
authors.initials: DJ
authors.lastname: Reen
authors.forename: D S
authors.initials: DS
authors.lastname: O'Briain
authors.forename: M
authors.initials: M
authors.lastname: McDermott
authors.forename: P
authors.initials: P
authors.lastname: Puri
mesh_terms: D001062:Appendectomy; D001064:Appendicitis / Q000175:diagnosis / Q000473:pathology* / Q000601:surgery*; D001065:Appendix / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D016022:Case-Control Studies; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D015232:Dinoprostone / Q000378:metabolism; D004630:Emergencies; D000949:Histocompatibility Antigens Class II / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D007249:Inflammation / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism; D007413:Intestinal Mucosa / Q000276:immunology / Q000378:metabolism / Q000473:pathology; D007527:Isoenzymes / Q000378:metabolism; D008565:Membrane Proteins; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052247:Nitric Oxide Synthase Type II; D011451:Prostaglandin-Endoperoxide Synthases / Q000378:metabolism
chemical_list: D000949:Histocompatibility Antigens Class II; D018836:Inflammation Mediators; D007527:Isoenzymes; D008565:Membrane Proteins; C496319:NOS2 protein, human; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496511:PTGS1 protein, human; C496540:PTGS2 protein, human; D011451:Prostaglandin-Endoperoxide Synthases; D015232:Dinoprostone