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Protein S Deficiency: An autosomal dominant disorder showing decreased levels of plasma protein S antigen or activity, associated with venous thrombosis and pulmonary embolism. PROTEIN S is a vitamin K-dependent plasma protein that inhibits blood clotting by serving as a cofactor for activated PROTEIN C (also a vitamin K-dependent protein), and the clinical manifestations of its deficiency are virtually identical to those of protein C deficiency. Treatment with heparin for acute thrombotic processes is usually followed by maintenance administration of coumarin drugs for the prevention of recurrent thrombosis. (From Harrison's Principles of Internal Medicine, 12th ed, p1511; Wintrobe's Clinical Hematology, 9th ed, p1523)Protein S: The vitamin K-dependent cofactor of activated PROTEIN C. Together with protein C, it inhibits the action of factors VIIIa and Va. A deficiency in protein S; (PROTEIN S DEFICIENCY); can lead to recurrent venous and arterial thrombosis.Protein C Deficiency: An absence or deficiency in PROTEIN C which leads to impaired regulation of blood coagulation. It is associated with an increased risk of severe or premature thrombosis. (Stedman's Med. Dict., 26th ed.)Thrombophilia: A disorder of HEMOSTASIS in which there is a tendency for the occurrence of THROMBOSIS.Dimenhydrinate: A drug combination that contains diphenhydramine and theophylline. It is used for treating VERTIGO, MOTION SICKNESS, and NAUSEA associated with PREGNANCY.Antithrombin III Deficiency: An absence or reduced level of Antithrombin III leading to an increased risk for thrombosis.Thrombophlebitis: Inflammation of a vein associated with a blood clot (THROMBUS).Sneddon Syndrome: A systemic non-inflammatory arteriopathy primarily of middle-aged females characterized by the association of livedo reticularis, multiple thrombotic CEREBRAL INFARCTION; CORONARY DISEASE, and HYPERTENSION. Elevation of antiphospholipid antibody titers (see also ANTIPHOSPHOLIPID SYNDROME), cardiac valvulopathy, ISCHEMIC ATTACK, TRANSIENT; SEIZURES; DEMENTIA; and chronic ischemia of the extremities may also occur. Pathologic examination of affected arteries reveals non-inflammatory adventitial fibrosis, thrombosis, and changes in the media. (From Jablonski, Dictionary of Syndromes & Eponymic Diseases, 2d ed; Adams et al., Principles of Neurology, 6th ed, p861; Arch Neurol 1997 Jan;54(1):53-60)Sagittal Sinus Thrombosis: Formation or presence of a blood clot (THROMBUS) in the SUPERIOR SAGITTAL SINUS or the inferior sagittal sinus. Sagittal sinus thrombosis can result from infections, hematological disorders, CRANIOCEREBRAL TRAUMA; and NEUROSURGICAL PROCEDURES. Clinical features are primarily related to the increased intracranial pressure causing HEADACHE; NAUSEA; and VOMITING. Severe cases can evolve to SEIZURES or COMA.Factor V Deficiency: A deficiency of blood coagulation factor V (known as proaccelerin or accelerator globulin or labile factor) leading to a rare hemorrhagic tendency known as Owren's disease or parahemophilia. It varies greatly in severity. Factor V deficiency is an autosomal recessive trait. (Dorland, 27th ed)Factor V: Heat- and storage-labile plasma glycoprotein which accelerates the conversion of prothrombin to thrombin in blood coagulation. Factor V accomplishes this by forming a complex with factor Xa, phospholipid, and calcium (prothrombinase complex). Deficiency of factor V leads to Owren's disease.Protein C: A vitamin-K dependent zymogen present in the blood, which, upon activation by thrombin and thrombomodulin exerts anticoagulant properties by inactivating factors Va and VIIIa at the rate-limiting steps of thrombin formation.Superior Sagittal Sinus: The long large endothelium-lined venous channel on the top outer surface of the brain. It receives blood from a vein in the nasal cavity, runs backwards, and gradually increases in size as blood drains from veins of the brain and the DURA MATER. Near the lower back of the CRANIUM, the superior sagittal sinus deviates to one side (usually the right) and continues on as one of the TRANSVERSE SINUSES.Immunoelectrophoresis, Two-Dimensional: Immunoelectrophoresis in which a second electrophoretic transport is performed on the initially separated antigen fragments into an antibody-containing medium in a direction perpendicular to the first electrophoresis.Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.Sinus Thrombosis, Intracranial: Formation or presence of a blood clot (THROMBUS) in the CRANIAL SINUSES, large endothelium-lined venous channels situated within the SKULL. Intracranial sinuses, also called cranial venous sinuses, include the superior sagittal, cavernous, lateral, petrous sinuses, and many others. Cranial sinus thrombosis can lead to severe HEADACHE; SEIZURE; and other neurological defects.Activated Protein C Resistance: A hemostatic disorder characterized by a poor anticoagulant response to activated protein C (APC). The activated form of Factor V (Factor Va) is more slowly degraded by activated protein C. Factor V Leiden mutation (R506Q) is the most common cause of APC resistance.Ribosomal Protein S6: A ribosomal protein that may play a role in controlling cell growth and proliferation. It is a major substrate of RIBOSOMAL PROTEIN S6 KINASES and plays a role in regulating the translation (TRANSLATION, GENETIC) of RNAs that contain an RNA 5' TERMINAL OLIGOPYRIMIDINE SEQUENCE.Blood Coagulation Tests: Laboratory tests for evaluating the individual's clotting mechanism.Point Mutation: A mutation caused by the substitution of one nucleotide for another. This results in the DNA molecule having a change in a single base pair.Pedigree: The record of descent or ancestry, particularly of a particular condition or trait, indicating individual family members, their relationships, and their status with respect to the trait or condition.Glycoproteins: Conjugated protein-carbohydrate compounds including mucins, mucoid, and amyloid glycoproteins.Ribosomal Proteins: Proteins found in ribosomes. They are believed to have a catalytic function in reconstituting biologically active ribosomal subunits.DNA Mutational Analysis: Biochemical identification of mutational changes in a nucleotide sequence.Complement C1s: A 77-kDa subcomponent of complement C1, encoded by gene C1S, is a SERINE PROTEASE existing as a proenzyme (homodimer) in the intact complement C1 complex. Upon the binding of COMPLEMENT C1Q to antibodies, the activated COMPLEMENT C1R cleaves C1s into two chains, A (heavy) and B (light, the serine protease), linked by disulfide bonds yielding the active C1s. The activated C1s, in turn, cleaves COMPLEMENT C2 and COMPLEMENT C4 to form C4b2a (CLASSICAL C3 CONVERTASE).