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Query: UMLS:C0042109 (urticaria)
 6,569 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

IgE is a homocytotropic antibody which binds to the surface of the mast cell. Antigen with affinity for IgE triggers conformational change at the cell surface, resulting in the release of chemical mediators from the mast cell granules. The mediators histamine, slow reacting substance of anaphylaxis and eosinophil chemotactic factor cause smooth muscle contraction, increased capillary permeability, eosinophil attraction and increased glandular secretions. The release of mediators from the mast cell granules is controlled by intracellular levels of cyclic nucleotides. In particular, elevated cyclic AMP inhibits mediator release. Adrenergic, cholinergic and prostaglandin receptors all influence mediator release. The characteristic immunopathology of immediate hypersensitivity reactions is a result of local or systemic mediator release. Such reactions include anaphylaxis, asthma, allergic rhinitis, urticaria and angioedema. Similar immunopathology may sometimes result from mechanisms not involving IgE or histamine mediators. Routine investigation of patients with immediate hypersensitivity should include eosinophil counts and IgE levels in blood and secretions, and immediate hypersensitivity skin tests. RAST testing is not routine. Therapeutic principles of these reactions include restoration of inhibitory levels of cyclic nucleotides, antagonism of mediator effects and immunological manipulation of the IgE mediated allergic reaction.
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PMID:The immunological basis of immediate hypersensitivity. 8 47

Actual concepts of urticaria immunopathology are briefly discussed, emphasizing the cytokine and inflammatory cells network.
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PMID:Immunopathology of urticaria. 172 47

There are several types of immunological tests available for the diagnosis and management of Helicobacter pylori infection. Most commercially available serological kits use the enzyme linked immunosorbent assay (ELISA) test format. Originally the kits used crude antigen preparations although many of the newer kits use a more purified antigen preparation, with often increased specificity but lower sensitivity. Near patient test kits are based either on latex agglutination or immunochromatography. Generally they have low sensitivities compared with laboratory tests. Western blotting, ELISA, and recombinant immunoblot assays (RIBA) have also been developed into commercially available kits and can be used to indicate the presence of specific virulence markers. An antigen detection kit has been developed for the detection of Helicobacter pylori in faeces. Immunological reagents have also been combined with other diagnostic modalities to develop immunohistochemical stains and DNA immunoassays. Helicobacter pylori is now recognised as the cause of gastritis and most cases of peptic ulcer disease (PUD); its long term carriage increases the risk of gastric adenocarcinoma sixfold and it is designated as a class I carcinogen. H pylori has also been implicated as a cause of gastric mucosa associated lymphoid tissue lymphomas. Its relation to non-ulcer dyspepsia remains controversial. Additionally, long term carriage of the organism may be associated with short stature in young girls and, in the general population, as a possible risk factor for the development of vasospastic disorders and possibly skin immunopathology such as urticaria. With the recognition of H pylori as an important human pathogen, it has become one of the growing number of organisms to have its complete genome sequence mapped. Serology is an important method of determining colonisation status and can be used for diagnosis, as a screening procedure, or to follow the efficacy of eradication regimens. Most serological assays are in the ELISA format although some are based on the latex agglutination reaction. These latter are used principally as near patient assays. Most assays detect IgG in serum although some detect serum IgA. More recently developed assays detect IgA in saliva and the production of affinity purified antibodies has led to the development of an antigen detection assay for faecal specimens. Serological reagents have also been used in immunocytochemistry and to speed up the detection of amplified products of the polymerase chain reaction (PCR)-DNA immunoassays.
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PMID:New immunological assays for the diagnosis of Helicobacter pylori infection. 1045 32