The internal resistance of the BLOOD to shear forces. The in vitro measure of whole blood viscosity is of limited clinical utility because it bears little relationship to the actual viscosity within the circulation, but an increase in the viscosity of circulating blood can contribute to morbidity in patients suffering from disorders such as SICKLE CELL ANEMIA and POLYCYTHEMIA.
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.
The formation of clumps of RED BLOOD CELLS under low or non-flow conditions, resulting from the attraction forces between the red blood cells. The cells adhere to each other in rouleaux aggregates. Slight mechanical force, such as occurs in the circulation, is enough to disperse these aggregates. Stronger or weaker than normal aggregation may result from a variety of effects in the ERYTHROCYTE MEMBRANE or in BLOOD PLASMA. The degree of aggregation is affected by ERYTHROCYTE DEFORMABILITY, erythrocyte membrane sialylation, masking of negative surface charge by plasma proteins, etc. BLOOD VISCOSITY and the ERYTHROCYTE SEDIMENTATION RATE are affected by the amount of erythrocyte aggregation and are parameters used to measure the aggregation.
The deformation and flow behavior of BLOOD and its elements i.e., PLASMA; ERYTHROCYTES; WHITE BLOOD CELLS; and BLOOD PLATELETS.
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.
The study of the deformation and flow of matter, usually liquids or fluids, and of the plastic flow of solids. The concept covers consistency, dilatancy, liquefaction, resistance to flow, shearing, thixotrophy, and VISCOSITY.
Ability of ERYTHROCYTES to change shape as they pass through narrow spaces, such as the microvasculature.
Exchange Transfusion, Whole Blood
Repetitive withdrawal of small amounts of blood and replacement with donor blood until a large proportion of the blood volume has been exchanged. Used in treatment of fetal erythroblastosis, hepatic coma, sickle cell anemia, disseminated intravascular coagulation, septicemia, burns, thrombotic thrombopenic purpura, and fulminant malaria.
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.
Blood Flow Velocity
The internal resistance of a material to moving some parts of it parallel to a fixed plane, in contrast to stretching (TENSILE STRENGTH) or compression (COMPRESSIVE STRENGTH). Ionic crystals are brittle because, when subjected to shear, ions of the same charge are brought next to each other, which causes repulsion.
The transfer of erythrocytes from a donor to a recipient or reinfusion to the donor.
The oxygen-carrying proteins of ERYTHROCYTES. They are found in all vertebrates and some invertebrates. The number of globin subunits in the hemoglobin quaternary structure differs between species. Structures range from monomeric to a variety of multimeric arrangements.
Anemia, Sickle Cell
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.
Paraparesis, Tropical Spastic
A subacute paralytic myeloneuropathy occurring endemically in tropical areas such as the Caribbean, Colombia, India, and Africa, as well as in the southwestern region of Japan; associated with infection by HUMAN T-CELL LEUKEMIA VIRUS I. Clinical manifestations include a slowly progressive spastic weakness of the legs, increased reflexes, Babinski signs, incontinence, and loss of vibratory and position sensation. On pathologic examination inflammatory, demyelination, and necrotic lesions may be found in the spinal cord. (Adams et al., Principles of Neurology, 6th ed, p1239)
Human T-lymphotropic virus 1
A strain of PRIMATE T-LYMPHOTROPIC VIRUS 1 isolated from mature T4 cells in patients with T-lymphoproliferation malignancies. It causes adult T-cell leukemia (LEUKEMIA-LYMPHOMA, T-CELL, ACUTE, HTLV-I-ASSOCIATED), T-cell lymphoma (LYMPHOMA, T-CELL), and is involved in mycosis fungoides, SEZARY SYNDROME and tropical spastic paraparesis (PARAPARESIS, TROPICAL SPASTIC).
Impairment of the ability to coordinate the movements required for normal ambulation (WALKING) which may result from impairments of motor function or sensory feedback. This condition may be associated with BRAIN DISEASES (including CEREBELLAR DISEASES and BASAL GANGLIA DISEASES); SPINAL CORD DISEASES; or PERIPHERAL NERVOUS SYSTEM DISEASES.
A plant genus of the family EUPHORBIACEAE that is perennial with conspicuous, almost palmate leaves like those of RICINUS but more deeply parted into five to nine lobes. It is a source of a starch after removal of the cyanogenic glucosides. The common name of Arrowroot is also used with Maranta (MARANTACEAE). The common name of yuca is also used for YUCCA.
A system of units used in scientific work throughout the world and employed in general commercial transactions and engineering applications. Its units of length, time, and mass are the meter, second, and kilogram respectively, or decimal multiples and submultiples thereof. ( McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
Simple protein, one of the prolamines, derived from the gluten of wheat, rye, etc. May be separated into 4 discrete electrophoretic fractions. It is the toxic factor associated with CELIAC DISEASE.