Loading...
Platelet-Rich Plasma: A preparation consisting of PLATELETS concentrated in a limited volume of PLASMA. This is used in various surgical tissue regeneration procedures where the GROWTH FACTORS in the platelets enhance wound healing and regeneration.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.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.Plasma: The residual portion of BLOOD that is left after removal of BLOOD CELLS by CENTRIFUGATION without prior BLOOD COAGULATION.Bone Regeneration: Renewal or repair of lost bone tissue. It excludes BONY CALLUS formed after BONE FRACTURES but not yet replaced by hard bone.Adenosine Diphosphate: Adenosine 5'-(trihydrogen diphosphate). An adenine nucleotide containing two phosphate groups esterified to the sugar moiety at the 5'-position.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.Platelet Adhesiveness: The process whereby PLATELETS adhere to something other than platelets, e.g., COLLAGEN; BASEMENT MEMBRANE; MICROFIBRILS; or other "foreign" surfaces.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.Alveoloplasty: Conservative contouring of the alveolar process, in preparation for immediate or future denture construction. (Dorland, 28th ed)Bone Substitutes: Synthetic or natural materials for the replacement of bones or bone tissue. They include hard tissue replacement polymers, natural coral, hydroxyapatite, beta-tricalcium phosphate, and various other biomaterials. The bone substitutes as inert materials can be incorporated into surrounding tissue or gradually replaced by original tissue.Blood Transfusion, Autologous: Reinfusion of blood or blood products derived from the patient's own circulation. (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.Thromboxane B2: A stable, physiologically active compound formed in vivo from the prostaglandin endoperoxides. It is important in the platelet-release reaction (release of ADP and serotonin).Blood Platelet Disorders: Disorders caused by abnormalities in platelet count or function.Thrombin: An enzyme formed from PROTHROMBIN that converts FIBRINOGEN to FIBRIN.Blood Coagulation Tests: Laboratory tests for evaluating the individual's clotting mechanism.Platelet Count: The number of PLATELETS per unit volume in a sample of venous BLOOD.Wound Healing: Restoration of integrity to traumatized tissue.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.Centrifugation: Process of using a rotating machine to generate centrifugal force to separate substances of different densities, remove moisture, or simulate gravitational effects. It employs a large motor-driven apparatus with a long arm, at the end of which human and animal subjects, biological specimens, or equipment can be revolved and rotated at various speeds to study gravitational effects. (From Websters, 10th ed; McGraw-Hill Dictionary of Scientific and Technical Terms, 4th ed)Tendinopathy: Clinical syndrome describing overuse tendon injuries characterized by a combination of PAIN, diffuse or localized swelling, and impaired performance. Distinguishing tendinosis from tendinitis is clinically difficult and can be made only after histopathological examination.Serotonin: A biochemical messenger and regulator, synthesized from the essential amino acid L-TRYPTOPHAN. In humans it is found primarily in the central nervous system, gastrointestinal tract, and blood platelets. Serotonin mediates several important physiological functions including neurotransmission, gastrointestinal motility, hemostasis, and cardiovascular integrity. Multiple receptor families (RECEPTORS, SEROTONIN) explain the broad physiological actions and distribution of this biochemical mediator.Bleeding Time: Duration of blood flow after skin puncture. This test is used as a measure of capillary and platelet function.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.Thromboxanes: Physiologically active compounds found in many organs of the body. They are formed in vivo from the prostaglandin endoperoxides and cause platelet aggregation, contraction of arteries, and other biological effects. Thromboxanes are important mediators of the actions of polyunsaturated fatty acids transformed by cyclooxygenase.Patellar Ligament: A band of fibrous tissue that attaches the apex of the PATELLA to the lower part of the tubercle of the TIBIA. The ligament is actually the caudal continuation of the common tendon of the QUADRICEPS FEMORIS. The patella is embedded in that tendon. As such, the patellar ligament can be thought of as connecting the quadriceps femoris tendon to the tibia, and therefore it is sometimes called the patellar tendon.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.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).Calcium Gluconate: The calcium salt of gluconic acid. The compound has a variety of uses, including its use as a calcium replenisher in hypocalcemic states.Platelet Transfusion: The transfer of blood platelets from a donor to a recipient or reinfusion to the donor.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.Thromboxane A2: An unstable intermediate between the prostaglandin endoperoxides and thromboxane B2. The compound has a bicyclic oxaneoxetane structure. It is a potent inducer of platelet aggregation and causes vasoconstriction. It is the principal component of rabbit aorta contracting substance (RCS).Prostaglandins D: Physiologically active prostaglandins found in many tissues and organs. They show pressor activity, are mediators of inflammation, and have potential antithrombotic effects.Blood Coagulation: The process of the interaction of BLOOD COAGULATION FACTORS that results in an insoluble FIBRIN clot.Aspirin: The prototypical analgesic used in the treatment of mild to moderate pain. It has anti-inflammatory and antipyretic properties and acts as an inhibitor of cyclooxygenase which results in the inhibition of the biosynthesis of prostaglandins. Aspirin also inhibits platelet aggregation and is used in the prevention of arterial and venous thrombosis. (From Martindale, The Extra Pharmacopoeia, 30th ed, p5)Platelet Function Tests: Laboratory examination used to monitor and evaluate platelet function in a patient's blood.Thrombosis: Formation and development of a thrombus or blood clot in the blood vessel.Apyrase: A calcium-activated enzyme that catalyzes the hydrolysis of ATP to yield AMP and orthophosphate. It can also act on ADP and other nucleoside triphosphates and diphosphates. EC 3.6.1.5.Gels: Colloids with a solid continuous phase and liquid as the dispersed phase; gels may be unstable when, due to temperature or other cause, the solid phase liquefies; the resulting colloid is called a sol.Tooth Socket: A hollow part of the alveolar process of the MAXILLA or MANDIBLE where each tooth fits and is attached via the periodontal ligament.Prostaglandin Endoperoxides, Synthetic: Synthetic compounds that are analogs of the naturally occurring prostaglandin endoperoxides and that mimic their pharmacologic and physiologic activities. They are usually more stable than the naturally occurring compounds.Pseudarthrosis: A pathologic entity characterized by deossification of a weight-bearing long bone, followed by bending and pathologic fracture, with inability to form normal BONY CALLUS leading to existence of the "false joint" that gives the condition its name. (Dorland, 27th ed)Oral Surgical Procedures, Preprosthetic: Surgery necessary for a denture to rest on a firm base, free from marked osseous protuberances or undercuts, and devoid of interfering muscle attachments, excess mucoperiosteum, hyperplasias, and fibrous or papillary growths.von Willebrand Diseases: Group of hemorrhagic disorders in which the VON WILLEBRAND FACTOR is either quantitatively or qualitatively abnormal. They are usually inherited as an autosomal dominant trait though rare kindreds are autosomal recessive. Symptoms vary depending on severity and disease type but may include prolonged bleeding time, deficiency of factor VIII, and impaired platelet adhesion.Guided Tissue Regeneration, Periodontal: Techniques for enhancing and directing cell growth to repopulate specific parts of the PERIODONTIUM that have been damaged by PERIODONTAL DISEASES; TOOTH DISEASES; or TRAUMA, or to correct TOOTH ABNORMALITIES. Repopulation and repair is achieved by guiding the progenitor cells to reproduce in the desired location by blocking contact with surrounding tissue by use of membranes composed of synthetic or natural material that may include growth inducing factors as well.Fibrin: A protein derived from FIBRINOGEN in the presence of THROMBIN, which forms part of the blood clot.Calcium Phosphates: Calcium salts of phosphoric acid. These compounds are frequently used as calcium supplements.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.Adenine NucleotidesAutografts: Transplant comprised of an individual's own tissue, transferred from one part of the body to another.Thromboxane-A Synthase: An enzyme found predominantly in platelet microsomes. It catalyzes the conversion of PGG(2) and PGH(2) (prostaglandin endoperoxides) to thromboxane A2. EC 5.3.99.5.Tendon Injuries: Injuries to the fibrous cords of connective tissue which attach muscles to bones or other structures.Epoprostenol: A prostaglandin that is a powerful vasodilator and inhibits platelet aggregation. It is biosynthesized enzymatically from PROSTAGLANDIN ENDOPEROXIDES in human vascular tissue. The sodium salt has been also used to treat primary pulmonary hypertension (HYPERTENSION, PULMONARY).Arachidonic AcidsRabbits: The species Oryctolagus cuniculus, in the family Leporidae, order LAGOMORPHA. Rabbits are born in burrows, furless, and with eyes and ears closed. In contrast with HARES, rabbits have 22 chromosome pairs.Plateletpheresis: The preparation of platelet concentrates with the return of red cells and platelet-poor plasma to the donor.Fracture Healing: The physiological restoration of bone tissue and function after a fracture. It includes BONY CALLUS formation and normal replacement of bone tissue.Biocompatible Materials: Synthetic or natural materials, other than DRUGS, that are used to replace or repair any body TISSUES or bodily function.Blood Coagulation Factors: Endogenous substances, usually proteins, that are involved in the blood coagulation process.Blood Preservation: The process by which blood or its components are kept viable outside of the organism from which they are derived (i.e., kept from decay by means of a chemical agent, cooling, or a fluid substitute that mimics the natural state within the organism).Time Factors: Elements of limited time intervals, contributing to particular results or situations.CitratesBone Transplantation: The grafting of bone from a donor site to a recipient site.Blood Specimen Collection: The taking of a blood sample to determine its character as a whole, to identify levels of its component cells, chemicals, gases, or other constituents, to perform pathological examination, etc.Dogs: The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)P-Selectin: Cell adhesion molecule and CD antigen that mediates the adhesion of neutrophils and monocytes to activated platelets and endothelial cells.Platelet Activating Factor: A phospholipid derivative formed by PLATELETS; BASOPHILS; NEUTROPHILS; MONOCYTES; and MACROPHAGES. It is a potent platelet aggregating agent and inducer of systemic anaphylactic symptoms, including HYPOTENSION; THROMBOCYTOPENIA; NEUTROPENIA; and BRONCHOCONSTRICTION.Arachidonic Acid: An unsaturated, essential fatty acid. It is found in animal and human fat as well as in the liver, brain, and glandular organs, and is a constituent of animal phosphatides. It is formed by the synthesis from dietary linoleic acid and is a precursor in the biosynthesis of prostaglandins, thromboxanes, and leukotrienes.Prostaglandins: A group of compounds derived from unsaturated 20-carbon fatty acids, primarily arachidonic acid, via the cyclooxygenase pathway. They are extremely potent mediators of a diverse group of physiological processes.Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.Receptors, Prostaglandin: Cell surface receptors that bind prostaglandins with high affinity and trigger intracellular changes which influence the behavior of cells. Prostaglandin receptor subtypes have been tentatively named according to their relative affinities for the endogenous prostaglandins. They include those which prefer prostaglandin D2 (DP receptors), prostaglandin E2 (EP1, EP2, and EP3 receptors), prostaglandin F2-alpha (FP receptors), and prostacyclin (IP receptors).15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid: A stable prostaglandin endoperoxide analog which serves as a thromboxane mimetic. Its actions include mimicking the hydro-osmotic effect of VASOPRESSIN and activation of TYPE C PHOSPHOLIPASES. (From J Pharmacol Exp Ther 1983;224(1): 108-117; Biochem J 1984;222(1):103-110)Receptors, Thromboxane: Cell surface proteins that bind THROMBOXANES with high affinity and trigger intracellular changes influencing the behavior of cells. Some thromboxane receptors act via the inositol phosphate and diacylglycerol second messenger systems.Diabetic Foot: Common foot problems in persons with DIABETES MELLITUS, caused by any combination of factors such as DIABETIC NEUROPATHIES; PERIPHERAL VASCULAR DISEASES; and INFECTION. With the loss of sensation and poor circulation, injuries and infections often lead to severe foot ulceration, GANGRENE and AMPUTATION.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.Blood Cell Count: The number of LEUKOCYTES and ERYTHROCYTES per unit volume in a sample of venous BLOOD. A complete blood count (CBC) also includes measurement of the HEMOGLOBIN; HEMATOCRIT; and ERYTHROCYTE INDICES.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 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.Edetic Acid: A chelating agent that sequesters a variety of polyvalent cations such as CALCIUM. It is used in pharmaceutical manufacturing and as a food additive.