Steps in primary hemostatic
Hemostasis and Thrombosis
secondary hemostasis that
Elements of Hemostasis
pathways leading to hemostasis
Diagnosis and therapies
- Hemostasis: The process which spontaneously arrests the flow of BLOOD from vessels carrying blood under pressure. It is accomplished by contraction of the vessels, adhesion and aggregation of formed blood elements (eg. ERYTHROCYTE AGGREGATION), and the process of BLOOD COAGULATION.
- Hemostasis, Surgical: Control of bleeding during or after surgery.
- Humans: Members of the species Homo sapiens.
- Hemostasis, Endoscopic: Control of bleeding performed through the channel of the endoscope. Techniques include use of lasers, heater probes, bipolar electrocoagulation, and local injection. Endoscopic hemostasis is commonly used to treat bleeding esophageal and gastrointestinal varices and ulcers.
- Hemostatic Techniques: Techniques for controlling bleeding.
- Hemostatics: Agents acting to arrest the flow of blood. Absorbable hemostatics arrest bleeding either by the formation of an artificial clot or by providing a mechanical matrix that facilitates clotting when applied directly to the bleeding surface. These agents function more at the capillary level and are not effective at stemming arterial or venous bleeding under any significant intravascular pressure.
- Middle Aged
- Blood Coagulation Tests: Laboratory tests for evaluating the individual's clotting mechanism.
- Blood Coagulation: The process of the interaction of BLOOD COAGULATION FACTORS that results in an insoluble FIBRIN clot.
- Adult: A person having attained full growth or maturity. Adults are of 19 through 44 years of age. For a person between 19 and 24 years of age, YOUNG ADULT is available.
- Aged: A person 65 through 79 years of age. For a person older than 79 years, AGED, 80 AND OVER is available.
- Thrombin: An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.
- Stomach Ulcer: Ulceration of the GASTRIC MUCOSA due to contact with GASTRIC JUICE. It is often associated with HELICOBACTER PYLORI infection or consumption of nonsteroidal anti-inflammatory drugs (NSAIDS).
- Factor VIIa: Activated form of factor VII. Factor VIIa activates factor X in the extrinsic pathway of blood coagulation.
- Punctures: Incision of tissues for injection of medication or for other diagnostic or therapeutic procedures. Punctures of the skin, for example may be used for diagnostic drainage; of blood vessels for diagnostic imaging procedures.
- Duodenal Ulcer: A PEPTIC ULCER located in the DUODENUM.
- Fibrinolysis: The natural enzymatic dissolution of FIBRIN.
- Bleeding Time: Duration of blood flow after skin puncture. This test is used as a measure of capillary and platelet function.
- Treatment Outcome: Evaluation undertaken to assess the results or consequences of management and procedures used in combating disease in order to determine the efficacy, effectiveness, safety, practicability, etc., of these interventions in individual cases or series.
- Animals: Unicellular or multicellular, heterotrophic organisms, that have sensation and the power of voluntary movement. Under the older five kingdom paradigm, Animalia was one of the kingdoms. Under the modern three domain model, Animalia represents one of the many groups in the domain EUKARYOTA.
- Fibrin Tissue Adhesive: An autologous or commercial tissue adhesive containing FIBRINOGEN and THROMBIN. The commercial product is a two component system from human plasma that contains more than fibrinogen and thrombin. The first component contains highly concentrated fibrinogen, FACTOR VIII, fibronectin, and traces of other plasma proteins. The second component contains thrombin, calcium chloride, and antifibrinolytic agents such as APROTININ. Mixing of the two components promotes BLOOD CLOTTING and the formation and cross-linking of fibrin. The tissue adhesive is used for tissue sealing, HEMOSTASIS, and WOUND HEALING.
- Factor VII: Heat- and storage-stable plasma protein that is activated by tissue thromboplastin to form factor VIIa in the extrinsic pathway of blood coagulation. The activated form then catalyzes the activation of factor X to factor Xa.
- Fibrinogen: Plasma glycoprotein clotted by thrombin, composed of a dimer of three non-identical pairs of polypeptide chains (alpha, beta, gamma) held together by disulfide bonds. Fibrinogen clotting is a sol-gel change involving complex molecular arrangements: whereas fibrinogen is cleaved by thrombin to form polypeptides A and B, the proteolytic action of other enzymes yields different fibrinogen degradation products.
- Electrocoagulation: Procedures using an electrically heated wire or scalpel to treat hemorrhage (e.g., bleeding ulcers) and to ablate tumors, mucosal lesions, and refractory arrhythmias. It is different from ELECTROSURGERY which is used more for cutting tissue than destroying and in which the patient is part of the electric circuit.
- Thrombelastography: Use of a thrombelastograph, which provides a continuous graphic record of the physical shape of a clot during fibrin formation and subsequent lysis.
- Gelatin Sponge, Absorbable: Sterile, gelatin-base surgical sponge applied topically as an adjunct to hemostasis when the control of bleeding by conventional procedures is ineffective to reduce capillary ooze or is impractical. (From AMA Drug Evaluations Annual, 1994, p797)
- Platelet Aggregation: The attachment of PLATELETS to one another. This clumping together can be induced by a number of agents (e.g., THROMBIN; COLLAGEN) and is part of the mechanism leading to the formation of a THROMBUS.
- Prothrombin Time: Clotting time of PLASMA recalcified in the presence of excess TISSUE THROMBOPLASTIN. Factors measured are FIBRINOGEN; PROTHROMBIN; FACTOR V; FACTOR VII; and FACTOR X. It is used for monitoring anticoagulant therapy with COUMARINS.
- Platelet Activation: A series of progressive, overlapping events, triggered by exposure of the PLATELETS to subendothelial tissue. These events include shape change, adhesiveness, aggregation, and release reactions. When carried through to completion, these events lead to the formation of a stable hemostatic plug.
- Partial Thromboplastin Time: The time required for the appearance of FIBRIN strands following the mixing of PLASMA with phospholipid platelet substitute (e.g., crude cephalins, soybean phosphatides). It is a test of the intrinsic pathway (factors VIII, IX, XI, and XII) and the common pathway (fibrinogen, prothrombin, factors V and X) of BLOOD COAGULATION. It is used as a screening test and to monitor HEPARIN therapy.
- Femoral Artery: The main artery of the thigh, a continuation of the external iliac artery.
- Coagulants: Agents that cause clotting.
- Cellulose, Oxidized: A cellulose of varied carboxyl content retaining the fibrous structure. It is used as a local hemostatic and as a matrix for normal blood coagulation.
- Tissue Adhesives: Substances used to cause adherence of tissue to tissue or tissue to non-tissue surfaces, as for prostheses.
- Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.
- Blood Coagulation Factors: Endogenous substances, usually proteins, that are involved in the blood coagulation process.
- Epinephrine: The active sympathomimetic hormone from the ADRENAL MEDULLA. It stimulates both the alpha- and beta- adrenergic systems, causes systemic VASOCONSTRICTION and gastrointestinal relaxation, stimulates the HEART, and dilates BRONCHI and cerebral vessels. It is used in ASTHMA and CARDIAC FAILURE and to delay absorption of local ANESTHETICS.
- Surgical Instruments: Hand-held tools or implements used by health professionals for the performance of surgical tasks.
- von Willebrand Factor: A high-molecular-weight plasma protein, produced by endothelial cells and megakaryocytes, that is part of the factor VIII/von Willebrand factor complex. The von Willebrand factor has receptors for collagen, platelets, and ristocetin activity as well as the immunologically distinct antigenic determinants. It functions in adhesion of platelets to collagen and hemostatic plug formation. The prolonged bleeding time in VON WILLEBRAND DISEASES is due to the deficiency of this factor.
- Prospective Studies: Observation of a population for a sufficient number of persons over a sufficient number of years to generate incidence or mortality rates subsequent to the selection of the study group.
- Thrombin Time: Clotting time of PLASMA mixed with a THROMBIN solution. It is a measure of the conversion of FIBRINOGEN to FIBRIN, which is prolonged by AFIBRINOGENEMIA, abnormal fibrinogen, or the presence of inhibitory substances, e.g., fibrin-fibrinogen degradation products, or HEPARIN. BATROXOBIN, a thrombin-like enzyme unaffected by the presence of heparin, may be used in place of thrombin.
- Aged, 80 and over: A person 80 years of age and older.
- Platelet Function Tests
- Factor VIII: Blood-coagulation factor VIII. Antihemophilic factor that is part of the factor VIII/von Willebrand factor complex. Factor VIII is produced in the liver and acts in the intrinsic pathway of blood coagulation. It serves as a cofactor in factor X activation and this action is markedly enhanced by small amounts of thrombin.
- Platelet Adhesiveness: The process whereby PLATELETS adhere to something other than platelets, e.g., COLLAGEN; BASEMENT MEMBRANE; MICROFIBRILS; or other "foreign" surfaces.
- Time Factors: Elements of limited time intervals, contributing to particular results or situations.
- Early Ambulation: Procedure to accelerate the ability of a patient to walk or move about by reducing the time to AMBULATION. It is characterized by a shorter period of hospitalization or recumbency than is normally practiced.
- Blood Transfusion: The introduction of whole blood or blood component directly into the blood stream. (Dorland, 27th ed)
- Equipment Design
- Blood Platelets: Non-nucleated disk-shaped cells formed in the megakaryocyte and found in the blood of all mammals. They are mainly involved in blood coagulation.
- Blood Coagulation Disorders: Hemorrhagic and thrombotic disorders that occur as a consequence of abnormalities in blood coagulation due to a variety of factors such as COAGULATION PROTEIN DISORDERS; BLOOD PLATELET DISORDERS; BLOOD PROTEIN DISORDERS or nutritional conditions.
- Prothrombin: A plasma protein that is the inactive precursor of thrombin. It is converted to thrombin by a prothrombin activator complex consisting of factor Xa, factor V, phospholipid, and calcium ions. Deficiency of prothrombin leads to hypoprothrombinemia.
- Adolescent: A person 13 to 18 years of age.
- Retrospective Studies: Studies used to test etiologic hypotheses in which inferences about an exposure to putative causal factors are derived from data relating to characteristics of persons under study or to events or experiences in their past. The essential feature is that some of the persons under study have the disease or outcome of interest and their characteristics are compared with those of unaffected persons.
- Recombinant Proteins: Proteins prepared by recombinant DNA technology.
- Whole Blood Coagulation Time: The time required by whole blood to produce a visible clot.
- Platelet Count: The number of PLATELETS per unit volume in a sample of venous BLOOD.
- Tampons, Surgical: Plugs or cylinders made of cotton, sponge, or other absorbent material. They are used in surgery to absorb fluids such as blood or drainage.
- Bandages: Material used for wrapping or binding any part of the body.
- Factor IX: Storage-stable blood coagulation factor acting in the intrinsic pathway. Its activated form, IXa, forms a complex with factor VIII and calcium on platelet factor 3 to activate factor X to Xa. Deficiency of factor IX results in HEMOPHILIA B (Christmas Disease).
- Ligation: Application of a ligature to tie a vessel or strangulate a part.
- Blood Loss, Surgical: Loss of blood during a surgical procedure.
- Anticoagulants: Agents that prevent clotting.
- Factor XIII: A fibrin-stabilizing plasma enzyme (TRANSGLUTAMINASES) that is activated by THROMBIN and CALCIUM to form FACTOR XIIIA. It is important for stabilizing the formation of the fibrin polymer (clot) which culminates the coagulation cascade.
- Hemorrhage: Bleeding or escape of blood from a vessel.
- Plasma: The residual portion of BLOOD that is left after removal of BLOOD CELLS by CENTRIFUGATION without prior BLOOD COAGULATION.
- Endoscopy, Gastrointestinal: Endoscopic examination, therapy or surgery of the gastrointestinal tract.
- Risk Factors: An aspect of personal behavior or lifestyle, environmental exposure, or inborn or inherited characteristic, which, on the basis of epidemiologic evidence, is known to be associated with a health-related condition considered important to prevent.
- Enbucrilate: A tissue adhesive that is applied as a monomer to moist tissue and polymerizes to form a bond. It is slowly biodegradable and used in all kinds of surgery, including dental.
- Antifibrinolytic Agents: Agents that prevent fibrinolysis or lysis of a blood clot or thrombus. Several endogenous antiplasmins are known. The drugs are used to control massive hemorrhage and in other coagulation disorders.
- Aprotinin: A single-chain polypeptide derived from bovine tissues consisting of 58 amino-acid residues. It is an inhibitor of proteolytic enzymes including CHYMOTRYPSIN; KALLIKREIN; PLASMIN; and TRYPSIN. It is used in the treatment of HEMORRHAGE associated with raised plasma concentrations of plasmin. It is also used to reduce blood loss and transfusion requirements in patients at high risk of major blood loss during and following open heart surgery with EXTRACORPOREAL CIRCULATION. (Reynolds JEF(Ed): Martindale: The Extra Pharmacopoeia (electronic version). Micromedex, Inc, Englewood, CO, 1995)
- Antithrombin III: A plasma alpha 2 glycoprotein that accounts for the major antithrombin activity of normal plasma and also inhibits several other enzymes. It is a member of the serpin superfamily.
- Blood Coagulation Factor Inhibitors: Substances, usually endogenous, that act as inhibitors of blood coagulation. They may affect one or multiple enzymes throughout the process. As a group, they also inhibit enzymes involved in processes other than blood coagulation, such as those from the complement system, fibrinolytic enzyme system, blood cells, and bacteria.
- Blood Component Transfusion: The transfer of blood components such as erythrocytes, leukocytes, platelets, and plasma from a donor to a recipient or back to the donor. This process differs from the procedures undertaken in PLASMAPHERESIS and types of CYTAPHERESIS; (PLATELETPHERESIS and LEUKAPHERESIS) where, following the removal of plasma or the specific cell components, the remainder is transfused back to the donor.
- Cyanoacrylates: A group of compounds having the general formula CH2=C(CN)-COOR; it polymerizes on contact with moisture; used as tissue adhesive; higher homologs have hemostatic and antibacterial properties.
- Pressure: A type of stress exerted uniformly in all directions. Its measure is the force exerted per unit area. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
- Thromboplastin: Constituent composed of protein and phospholipid that is widely distributed in many tissues. It serves as a cofactor with factor VIIa to activate factor X in the extrinsic pathway of blood coagulation.
- Acetylglucosamine: The N-acetyl derivative of glucosamine.
- Follow-Up Studies: Studies in which individuals or populations are followed to assess the outcome of exposures, procedures, or effects of a characteristic, e.g., occurrence of disease.
- Child: A person 6 to 12 years of age. An individual 2 to 5 years old is CHILD, PRESCHOOL.
- Fibrin: A protein derived from FIBRINOGEN in the presence of THROMBIN, which forms part of the blood clot.
- Deamino Arginine Vasopressin: A synthetic analog of the pituitary hormone, ARGININE VASOPRESSIN. Its action is mediated by the VASOPRESSIN receptor V2. It has prolonged antidiuretic activity, but little pressor effects. It also modulates levels of circulating FACTOR VIII and VON WILLEBRAND FACTOR.
- Recurrence: The return of a sign, symptom, or disease after a remission.
- 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.)
- Platelet Glycoprotein GPIb-IX Complex: Platelet membrane glycoprotein complex essential for normal platelet adhesion and clot formation at sites of vascular injury. It is composed of three polypeptides, GPIb alpha, GPIb beta, and GPIX. Glycoprotein Ib functions as a receptor for von Willebrand factor and for thrombin. Congenital deficiency of the GPIb-IX complex results in Bernard-Soulier syndrome. The platelet glycoprotein GPV associates with GPIb-IX and is also absent in Bernard-Soulier syndrome.
- Platelet Transfusion: The transfer of blood platelets from a donor to a recipient or reinfusion to the donor.
- Vasoconstrictor Agents: Drugs used to cause constriction of the blood vessels.
- Argon: Argon. A noble gas with the atomic symbol Ar, atomic number 18, and atomic weight 39.948. It is used in fluorescent tubes and wherever an inert atmosphere is desired and nitrogen cannot be used.
- Suture Techniques: Techniques for securing together the edges of a wound, with loops of thread or similar materials (SUTURES).
- Equipment Safety: Freedom of equipment from actual or potential hazards.
- Surgical Sponges: Gauze material used to absorb body fluids during surgery. Referred to as gossypiboma if accidentally retained in the body following surgery.
- Shock, Hemorrhagic: Acute hemorrhage or excessive fluid loss resulting in HYPOVOLEMIA.
- Collagen: A polypeptide substance comprising about one third of the total protein in mammalian organisms. It is the main constituent of SKIN; CONNECTIVE TISSUE; and the organic substance of bones (BONE AND BONES) and teeth (TOOTH).
- Hematocrit: The volume of packed RED BLOOD CELLS in a blood specimen. The volume is measured by centrifugation in a tube with graduated markings, or with automated blood cell counters. It is an indicator of erythrocyte status in disease. For example, ANEMIA shows a low value; POLYCYTHEMIA, a high value.
- Tourniquets: Devices for the compression of a blood vessel by application around an extremity to control the circulation and prevent the flow of blood to or from the distal area. (From Dorland, 28th ed)
- Sutures: Materials used in closing a surgical or traumatic wound. (From Dorland, 28th ed)
- Platelet Membrane Glycoproteins: Surface glycoproteins on platelets which have a key role in hemostasis and thrombosis such as platelet adhesion and aggregation. Many of these are receptors.
- Young Adult: A person between 19 and 24 years of age.
- Mice: The common name for the genus Mus.
- Hematologic Tests: Tests used in the analysis of the hemic system.
- Clinical Laboratory Techniques: Techniques used to carry out clinical investigative procedures in the diagnosis and therapy of disease.
- Tranexamic Acid: Antifibrinolytic hemostatic used in severe hemorrhage.
- Child, Preschool: A child between the ages of 2 and 5.
- Snake Venoms: Solutions or mixtures of toxic and nontoxic substances elaborated by snake (Ophidia) salivary glands for the purpose of killing prey or disabling predators and delivered by grooved or hollow fangs. They usually contain enzymes, toxins, and other factors.
- Embolization, Therapeutic: A method of hemostasis utilizing various agents such as Gelfoam, silastic, metal, glass, or plastic pellets, autologous clot, fat, and muscle as emboli. It has been used in the treatment of spinal cord and INTRACRANIAL ARTERIOVENOUS MALFORMATIONS, renal arteriovenous fistulas, gastrointestinal bleeding, epistaxis, hypersplenism, certain highly vascular tumors, traumatic rupture of blood vessels, and control of operative hemorrhage.
- Perioperative Care: Interventions to provide care prior to, during, and immediately after surgery.
- Venous Thrombosis: The formation or presence of a blood clot (THROMBUS) within a vein.
- Gastroscopy: Endoscopic examination, therapy or surgery of the interior of the stomach.
- Rhodnius: A genus of the subfamily TRIATOMINAE. Rhodnius prolixus is a vector for TRYPANOSOMA CRUZI.
- Palmitates: Salts and esters of the 16-carbon saturated monocarboxylic acid--palmitic acid.
- Administration, Topical: The application of drug preparations to the surfaces of the body, especially the skin (ADMINISTRATION, CUTANEOUS) or mucous membranes. This method of treatment is used to avoid systemic side effects when high doses are required at a localized area or as an alternative systemic administration route, to avoid hepatic processing for example.
- Thrombophilia: A disorder of HEMOSTASIS in which there is a tendency for the occurrence of THROMBOSIS.
- Hemodilution: Reduction of blood viscosity usually by the addition of cell free solutions. Used clinically (1) in states of impaired microcirculation, (2) for replacement of intraoperative blood loss without homologous blood transfusion, and (3) in cardiopulmonary bypass and hypothermia.
- Gelatin: A product formed from skin, white connective tissue, or bone COLLAGEN. It is used as a protein food adjuvant, plasma substitute, hemostatic, suspending agent in pharmaceutical preparations, and in the manufacturing of capsules and suppositories.
- Fibrinolytic Agents: Fibrinolysin or agents that convert plasminogen to FIBRINOLYSIN.
- Radial Artery: The direct continuation of the brachial trunk, originating at the bifurcation of the brachial artery opposite the neck of the radius. Its branches may be divided into three groups corresponding to the three regions in which the vessel is situated, the forearm, wrist, and hand.
- Thrombopoiesis: The process of generating thrombocytes (BLOOD PLATELETS) from the pluripotent HEMATOPOIETIC STEM CELLS in the BONE MARROW via the MEGAKARYOCYTES. The humoral factor with thrombopoiesis-stimulating activity is designated THROMBOPOIETIN.
- Factor X: Storage-stable glycoprotein blood coagulation factor that can be activated to factor Xa by both the intrinsic and extrinsic pathways. A deficiency of factor X, sometimes called Stuart-Prower factor deficiency, may lead to a systemic coagulation disorder.
- Femoral Vein: The vein accompanying the femoral artery in the same sheath; it is a continuation of the popliteal vein and becomes the external iliac vein.
- Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.
- Angiography: Radiography of blood vessels after injection of a contrast medium.
- Waxes: A plastic substance deposited by insects or obtained from plants. Waxes are esters of various fatty acids with higher, usually monohydric alcohols. The wax of pharmacy is principally yellow wax (beeswax), the material of which honeycomb is made. It consists chiefly of cerotic acid and myricin and is used in making ointments, cerates, etc. (Dorland, 27th ed)
- Platelet Aggregation Inhibitors: Drugs or agents which antagonize or impair any mechanism leading to blood platelet aggregation, whether during the phases of activation and shape change or following the dense-granule release reaction and stimulation of the prostaglandin-thromboxane system.
- Drug Combinations: Single preparations containing two or more active agents, for the purpose of their concurrent administration as a fixed dose mixture.
- Risk Assessment: The qualitative or quantitative estimation of the likelihood of adverse effects that may result from exposure to specified health hazards or from the absence of beneficial influences. (Last, Dictionary of Epidemiology, 1988)
- Models, Biological: Theoretical representations that simulate the behavior or activity of biological processes or diseases. For disease models in living animals, DISEASE MODELS, ANIMAL is available. Biological models include the use of mathematical equations, computers, and other electronic equipment.
- Heparin: A highly acidic mucopolysaccharide formed of equal parts of sulfated D-glucosamine and D-glucuronic acid with sulfaminic bridges. The molecular weight ranges from six to twenty thousand. Heparin occurs in and is obtained from liver, lung, mast cells, etc., of vertebrates. Its function is unknown, but it is used to prevent blood clotting in vivo and vitro, in the form of many different salts.
- Sclerotherapy: Treatment of varicose veins, hemorrhoids, gastric and esophageal varices, and peptic ulcer hemorrhage by injection or infusion of chemical agents which cause localized thrombosis and eventual fibrosis and obliteration of the vessels.
- Pregnancy: The status during which female mammals carry their developing young (EMBRYOS or FETUSES) in utero before birth, beginning from FERTILIZATION to BIRTH.
- Balloon Occlusion: Use of a balloon CATHETER to block the flow of blood through an artery or vein.
- Elapidae: A family of extremely venomous snakes, comprising coral snakes, cobras, mambas, kraits, and sea snakes. They are widely distributed, being found in the southern United States, South America, Africa, southern Asia, Australia, and the Pacific Islands. The elapids include three subfamilies: Elapinae, Hydrophiinae, and Lauticaudinae. Like the viperids, they have venom fangs in the front part of the upper jaw. The mambas of Africa are the most dangerous of all snakes by virtue of their size, speed, and highly toxic venom. (Goin, Goin, and Zug, Introduction to Herpetology, 3d ed, p329-33)
- International Normalized Ratio: System established by the World Health Organization and the International Committee on Thrombosis and Hemostasis for monitoring and reporting blood coagulation tests. Under this system, results are standardized using the International Sensitivity Index for the particular test reagent/instrument combination used.
- Receptors, Purinergic P2Y12: A subclass of purinergic P2Y receptors that have a preference for ADP binding and are coupled to GTP-BINDING PROTEIN ALPHA SUBUNIT, GI. The P2Y12 purinergic receptors are found in PLATELETS where they play an important role regulating PLATELET ACTIVATION.
- Mice, Knockout: Strains of mice in which certain GENES of their GENOMES have been disrupted, or "knocked-out". To produce knockouts, using RECOMBINANT DNA technology, the normal DNA sequence of the gene being studied is altered to prevent synthesis of a normal gene product. Cloned cells in which this DNA alteration is successful are then injected into mouse EMBRYOS to produce chimeric mice. The chimeric mice are then bred to yield a strain in which all the cells of the mouse contain the disrupted gene. Knockout mice are used as EXPERIMENTAL ANIMAL MODELS for diseases (DISEASE MODELS, ANIMAL) and to clarify the functions of the genes.
- Endoscopes, Gastrointestinal: Instruments for the visual examination of the interior of the gastrointestinal tract.
- Occlusive Dressings: Material, usually gauze or absorbent cotton, used to cover and protect wounds, to seal them from contact with air or bacteria. (From Dorland, 27th ed)
- Laparoscopy: A procedure in which a laparoscope (LAPAROSCOPES) is inserted through a small incision near the navel to examine the abdominal and pelvic organs in the PERITONEAL CAVITY. If appropriate, biopsy or surgery can be performed during laparoscopy.
- Clot Retraction: Retraction of a clot resulting from contraction of PLATELET pseudopods attached to FIBRIN strands. The retraction is dependent on the contractile protein thrombosthenin. Clot retraction is used as a measure of platelet function.
- Receptors, Collagen: Collagen receptors are cell surface receptors that modulate signal transduction between cells and the EXTRACELLULAR MATRIX. They are found in many cell types and are involved in the maintenance and regulation of cell shape and behavior, including PLATELET ACTIVATION and aggregation, through many different signaling pathways and differences in their affinities for collagen isoforms. Collagen receptors include discoidin domain receptors, INTEGRINS, and glycoprotein VI.
- Cardiopulmonary Bypass: Diversion of the flow of blood from the entrance of the right atrium directly to the aorta (or femoral artery) via an oxygenator thus bypassing both the heart and lungs.
- 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.
- Platelet Glycoprotein GPIIb-IIIa Complex: Platelet membrane glycoprotein complex important for platelet adhesion and aggregation. It is an integrin complex containing INTEGRIN ALPHAIIB and INTEGRIN BETA3 which recognizes the arginine-glycine-aspartic acid (RGD) sequence present on several adhesive proteins. As such, it is a receptor for FIBRINOGEN; VON WILLEBRAND FACTOR; FIBRONECTIN; VITRONECTIN; and THROMBOSPONDINS. A deficiency of GPIIb-IIIa results in GLANZMANN THROMBASTHENIA.
- Polytetrafluoroethylene: Homopolymer of tetrafluoroethylene. Nonflammable, tough, inert plastic tubing or sheeting; used to line vessels, insulate, protect or lubricate apparatus; also as filter, coating for surgical implants or as prosthetic material. Synonyms: Fluoroflex; Fluoroplast; Ftoroplast; Halon; Polyfene; PTFE; Tetron.
- Infant: A child between 1 and 23 months of age.
- Postoperative Hemorrhage: Hemorrhage following any surgical procedure. It may be immediate or delayed and is not restricted to the surgical wound.
- Acute Disease: Disease having a short and relatively severe course.
- Feasibility Studies: Studies to determine the advantages or disadvantages, practicability, or capability of accomplishing a projected plan, study, or project.
- Crotalid Venoms: Venoms from snakes of the subfamily Crotalinae or pit vipers, found mostly in the Americas. They include the rattlesnake, cottonmouth, fer-de-lance, bushmaster, and American copperhead. Their venoms contain nontoxic proteins, cardio-, hemo-, cyto-, and neurotoxins, and many enzymes, especially phospholipases A. Many of the toxins have been characterized.
- Ristocetin: An antibiotic mixture of two components, A and B, obtained from Nocardia lurida (or the same substance produced by any other means). It is no longer used clinically because of its toxicity. It causes platelet agglutination and blood coagulation and is used to assay those functions in vitro.
- Wound Healing: Restoration of integrity to traumatized tissue.
- Catheterization, Peripheral: Insertion of a catheter into a peripheral artery, vein, or airway for diagnostic or therapeutic purposes.
- Cardiac Surgical Procedures: Surgery performed on the heart.
- Disease Models, Animal: Naturally occurring or experimentally induced animal diseases with pathological processes sufficiently similar to those of human diseases. They are used as study models for human diseases.
- 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.
- Point-of-Care Systems: Laboratory and other services provided to patients at the bedside. These include diagnostic and laboratory testing using automated information entry.
- Integrin alpha2: An integrin alpha subunit that primarily combines with INTEGRIN BETA1 to form the INTEGRIN ALPHA2BETA1 heterodimer. It contains a domain which has homology to collagen-binding domains found in von Willebrand factor.
- Case-Control Studies: Studies which start with the identification of persons with a disease of interest and a control (comparison, referent) group without the disease. The relationship of an attribute to the disease is examined by comparing diseased and non-diseased persons with regard to the frequency or levels of the attribute in each group.
- Intraoperative Care: Patient care procedures performed during the operation that are ancillary to the actual surgery. It includes monitoring, fluid therapy, medication, transfusion, anesthesia, radiography, and laboratory tests.
- Hydroxyethyl Starch Derivatives: Starches that have been chemically modified so that a percentage of OH groups are substituted with 2-hydroxyethyl ether groups.
- Sclerosing Solutions: Chemical agents injected into blood vessels and lymphatic sinuses to shrink or cause localized THROMBOSIS; FIBROSIS, and obliteration of the vessels. This treatment is applied in a number of conditions such as VARICOSE VEINS; HEMORRHOIDS; GASTRIC VARICES; ESOPHAGEAL VARICES; PEPTIC ULCER HEMORRHAGE.
- Receptor, PAR-1: A thrombin receptor subtype that couples to HETEROTRIMERIC GTP-BINDING PROTEINS resulting in the activation of a variety of signaling mechanisms including decreased intracellular CYCLIC AMP, increased TYPE C PHOSPHOLIPASES and increased PHOSPHOLIPASE A2.
- Ultrasonics: A subfield of acoustics dealing in the radio frequency range higher than acoustic SOUND waves (approximately above 20 kilohertz). Ultrasonic radiation is used therapeutically (DIATHERMY and ULTRASONIC THERAPY) to generate HEAT and to selectively destroy tissues. It is also used in diagnostics, for example, ULTRASONOGRAPHY; ECHOENCEPHALOGRAPHY; and ECHOCARDIOGRAPHY, to visually display echoes received from irradiated tissues.
- Length of Stay: The period of confinement of a patient to a hospital or other health facility.
- Rupture, Spontaneous: Tear or break of an organ, vessel or other soft part of the body, occurring in the absence of external force.
- Protein Binding: The process in which substances, either endogenous or exogenous, bind to proteins, peptides, enzymes, protein precursors, or allied compounds. Specific protein-binding measures are often used as assays in diagnostic assessments.
- Hemorheology: The deformation and flow behavior of BLOOD and its elements i.e., PLASMA; ERYTHROCYTES; WHITE BLOOD CELLS; and BLOOD PLATELETS.
- Injections, Intralesional: Injections introduced directly into localized lesions.
- Lower Gastrointestinal Tract: The segment of GASTROINTESTINAL TRACT that includes the small intestine below the DUODENUM, and the LARGE INTESTINE.
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