Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0014118 (endocarditis)
 15,629 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The ability of endocarditis and dental strains of Streptococcus sanguis to induce platelet aggregation in plasma (PRP) from normal subjects were examined and compared to responses of PRP with known platelet membrane glycoprotein (GP) and response defects. S. sanguis strains differed in their ability to induce normal PRPs to aggregate. Strains that induced PRP aggregation in more than 60% of donors were significantly faster agonists (mean lag times to onset of aggregation less than 6 min) than those strains inducing response in PRPs of fewer than 60% of donors. Platelets from patients with Bernard-Soulier syndrome aggregated in response to strains of S. sanguis. In contrast, platelets from patients with Glanzmann's thrombasthenia and from a patient with a specific defect in response to collagen were unresponsive to S. sanguis. These observations show that GPIb and V are not essential, but GPIIb-IIIa and GPIa are important in the platelet response mechanism to S. sanguis. Indeed, the data suggests that the platelet interaction mechanisms of S. sanguis and collagen may be similar.
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PMID:Responses of platelets to strains of streptococcus sanguis: findings in healthy subjects, Bernard-Soulier, Glanzmann's, and collagen-unresponsive patients. 360 13

Numerous studies have implicated bacteria in cardiovascular disease, but there is a paucity of information on the mechanism involved. In this study we show how the common oral bacterium Streptococcus sanguis can directly interact with platelets, resulting in activation and aggregate formation. Platelet aggregation was dependent on glycoprotein IIb/IIIa (GPIIb/IIIa) and thromboxane. Platelets could also directly bind to S sanguis, but this interaction was not inhibited by GPIIb/IIIa antagonists. Antibodies to GPIb could inhibit both platelet aggregation and platelet adhesion to bacteria. This suggested a direct interaction between GPIb and S sanguis; however, this interaction did not require von Willebrand factor, the normal ligand for GPIb. By use of a range of monoclonal antibodies to GPIb and the enzyme mocharagin, which cleaves GPIb at amino acid 282, the interaction was localized to a region within the N-terminal 1-225 portion of GPIbalpha. Furthermore S sanguis failed to induce aggregation of platelets from a patient with Bernard-Soulier disease, the organism bound to Chinese hamster ovary cells transfected with the GPIbalpha gene but did not bind to mock-transfected cells and biotin-labeled S sanguis cells bound to purified GPIb in ligand blots. It is suggested that the interaction between S sanguis and GPIb is important in the pathogenesis of infective endocarditis and may also play a contributory role in some cases of myocardial infarction.
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PMID:A role for glycoprotein Ib in Streptococcus sanguis-induced platelet aggregation. 1209 42