Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0039483 (giant cell arteritis)
 3,204 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We applied a peroxidase-antiperoxidase technique to study the distribution pattern and binding characteristics of the lectin from the marine sponge Geodia cydonium (Geodia cydonium agglutinin; GCA) in various human tissues. This lectin has been shown to possess a broad reactivity, but there was a distinct distribution of binding sites within the different organs. In the histochemical system GCA displayed no blood group specificity and labeled red blood cells, the vascular endothelium, and epithelial cells showing blood group antigen expression independent of the ABH blood group status. However, inhibition of GCA reactivity by simple sugars and complex carbohydrates demonstrated tissue-specific differences of lectin binding related to the ABH blood group status of the tissue and revealed information on the structural requirements of the histological lectin binding site. Tissues that totally lacked blood group antigens or that expressed only the H-antigen disclosed a GCA reactivity which was completely inhibited by lactose. In contrast, tissues that expressed blood group A- or blood group B-antigen exhibited a lactose-resistant lectin binding which was inhibited only by water-soluble blood group substance A from peptone A and by bovine glycophorin but not by other complex carbohydrates, including human glycophorin and human asialoglycophorin. Competitive inhibition studies in situ revealed that GCA binding was not inhibited by blood group type I/II carbohydrate sequence-specific lectins or by lectins with other sugar specificities. Inhibition by lactose of GCA binding to some histological sites indicates that the binding site consists of a beta-linked galactose-containing disaccharide. However, periodate oxidation of tissue sections had no effect on lectin binding, pointing to a subterminal location of the relevant sequence. The results obtained from inhibition studies with simple saccharides and complex carbohydrates in relation to the expression of ABH blood group antigens suggest a complex lectin combining site(s) in histological specimens. The lectin may possess either one binding site with a range of affinities for different carbohydrates (besides beta-linked disaccharides the GCA binding site accommodates to carbohydrate determinants carrying the blood group A or blood group B determinant), or may possess two different binding sites. Besides an acceptor site for beta-linked disaccharides, an additional binding site may exist accommodating to extended carbohydrate sequences related to A or B blood group structures. In conclusion, GCA represents a blood group-nonspecific lectin whose binding affinities are determined by the ABH blood group status of the tissue.
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PMID:Histochemical reactivity of the Geodia cydonium agglutinin (GCA) in human tissues. 200 75

Markers of endothelial cell activation were measured in 28 patients presenting with various forms of limited or focal type cutaneous vasculitis. Plasma levels of tissue plasminogen activator antigen (t-PA:Ag), plasminogen activator inhibitor type 1 antigen (PAI-1:Ag) and PAI-1 activity, fibrin plate, von Willebrand factor antigen (vWF:Ag), tissue factor (TF) and soluble thrombomodulin (sTM) were measured. In comparison with the control group (n = 20) there was a significant increase in t-PA:Ag, vWF:Ag and TF (P < 0.05, Mann-Whitney U-test) in the cutaneous vasculitis group. This study confirms that measurable degrees of endothelial activation occur in cutaneous vasculitis. Cutaneous vasculitis includes a diverse group of clinical conditions, which are associated with inflammatory changes in cutaneous blood vessels with local fibrin deposition. The aetiology and pathogenesis of the majority of these entities remain unknown. Causative mediators are thought to include immune complexes, anti-endothelial cell antibodies, cytotoxic lymphocytes and viruses. Histologically, immune complexes and complement are frequently detected on the vessel wall, and serologically anti-endothelial antibodies are often detected in patients with vasculitis and in systemic lupus erythematosus (SLE) which correlate with the severity of cutaneous vasculitis, arthritis and nephritis. Lymphocyte-mediated toxicity to endothelial cells has been reported in a small number of patients with giant cell arteritis and Takayasu's arteritis. The vascular endothelium plays a central part in the control of haemostasis. Under physiological conditions endothelial cells present an anticoagulant surface to blood constituents, partially due to surface expression of heparan sulphate and thrombomodulin (TM). Heparan sulphate binds antithrombin III (ATIII), thereby accelerating inactivation of intrinsic coagulation enzymes. Thrombomodulin is an endothelial cell surface glycoprotein which promotes anticoagulation by forming a complex with thrombin which then activates protein C. Activated protein C together with a cofactor, protein S, inactivates FVa and FVIIIa. von Willebrand factor (vWF) is synthesized by endothelial cells, stored in Weibel-Palade bodies and released into the circulation upon endothelial stimulation. vWF mediates the binding of platelets to the subendothelium and is the carrier molecule for FVIIIC. The endothelium controls fibrinolysis by producing t-PA and its inhibitor PAI-1. Inflammatory cytokines such as interleukin-1 (IL-1) and tumour necrosis factor (TNF) activate endothelial cells, causing a shift from an antithrombotic to prothrombotic state, including expression of tissue factor, increased synthesis of PAI-1 and decreased expression of TM. Fibrin deposition and intravascular thrombosis are seen in cutaneous vasculitis syndromes, suggesting local endothelial cell activation. The aim of this pilot study was to assess whether perturbation of the endothelium in cutaneous vasculitis could be detected in the patients' plasma samples. If so, further studies to assess any correlation in levels of these markers with disease activity might prove useful in the future.
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PMID:Endothelial cell activation in cutaneous vasculitis. 868 65