Spherocytosis, Hereditary: A group of familial congenital hemolytic anemias characterized by numerous abnormally shaped erythrocytes which are generally spheroidal. The erythrocytes have increased osmotic fragility and are abnormally permeable to sodium ions.Spectrin: A high molecular weight (220-250 kDa) water-soluble protein which can be extracted from erythrocyte ghosts in low ionic strength buffers. The protein contains no lipids or carbohydrates, is the predominant species of peripheral erythrocyte membrane proteins, and exists as a fibrous coating on the inner, cytoplasmic surface of the membrane.Osmotic Fragility: RED BLOOD CELL sensitivity to change in OSMOTIC PRESSURE. When exposed to a hypotonic concentration of sodium in a solution, red cells take in more water, swell until the capacity of the cell membrane is exceeded, and burst.Anion Exchange Protein 1, Erythrocyte: A major integral transmembrane protein of the ERYTHROCYTE MEMBRANE. It is the anion exchanger responsible for electroneutral transporting in CHLORIDE IONS in exchange of BICARBONATE IONS allowing CO2 uptake and transport from tissues to lungs by the red blood cells. Genetic mutations that result in a loss of the protein function have been associated with type 4 HEREDITARY SPHEROCYTOSIS.Splenectomy: Surgical procedure involving either partial or entire removal of the spleen.Ankyrins: A family of membrane-associated proteins responsible for the attachment of the cytoskeleton. Erythrocyte-related isoforms of ankyrin attach the SPECTRIN cytoskeleton to a transmembrane protein (ANION EXCHANGE PROTEIN 1, ERYTHROCYTE) in the erythrocyte plasma membrane. Brain-related isoforms of ankyrin also exist.Anemia, Hemolytic: A condition of inadequate circulating red blood cells (ANEMIA) or insufficient HEMOGLOBIN due to premature destruction of red blood cells (ERYTHROCYTES).Erythrocytes, Abnormal: Oxygen-carrying RED BLOOD CELLS in mammalian blood that are abnormal in structure or function.Erythrocyte Membrane: The semi-permeable outer structure of a red blood cell. It is known as a red cell 'ghost' after HEMOLYSIS.Elliptocytosis, Hereditary: An intrinsic defect of erythrocytes inherited as an autosomal dominant trait. The erythrocytes assume an oval or elliptical shape.Erythrocyte Aging: The senescence of RED BLOOD CELLS. Lacking the organelles that make protein synthesis possible, the mature erythrocyte is incapable of self-repair, reproduction, and carrying out certain functions performed by other cells. This limits the average life span of an erythrocyte to 120 days.Gilbert Disease: A benign familial disorder, transmitted as an autosomal dominant trait. It is characterized by low-grade chronic hyperbilirubinemia with considerable daily fluctuations of the bilirubin level.Acanthocytes: Erythrocytes with protoplasmic projections giving the cell a thorny appearance.Erythrocyte Deformability: Ability of ERYTHROCYTES to change shape as they pass through narrow spaces, such as the microvasculature.Erythrocytes: Red blood cells. Mature erythrocytes are non-nucleated, biconcave disks containing HEMOGLOBIN whose function is to transport OXYGEN.Anemia, Hemolytic, Congenital: Hemolytic anemia due to various intrinsic defects of the erythrocyte.Reticulocytes: Immature ERYTHROCYTES. In humans, these are ERYTHROID CELLS that have just undergone extrusion of their CELL NUCLEUS. They still contain some organelles that gradually decrease in number as the cells mature. RIBOSOMES are last to disappear. Certain staining techniques cause components of the ribosomes to precipitate into characteristic "reticulum" (not the same as the ENDOPLASMIC RETICULUM), hence the name reticulocytes.Hematologic Tests: Tests used in the analysis of the hemic system.Splenomegaly: Enlargement of the spleen.Hemolysis: The destruction of ERYTHROCYTES by many different causal agents such as antibodies, bacteria, chemicals, temperature, and changes in tonicity.Chromium Isotopes: Stable chromium atoms that have the same atomic number as the element chromium, but differ in atomic weight. Cr-50, 53, and 54 are stable chromium isotopes.Anemia, Hemolytic, Autoimmune: Acquired hemolytic anemia due to the presence of AUTOANTIBODIES which agglutinate or lyse the patient's own RED BLOOD CELLS.Erythrocyte Count: The number of RED BLOOD CELLS per unit volume in a sample of venous BLOOD.Acidosis, Renal Tubular: A group of genetic disorders of the KIDNEY TUBULES characterized by the accumulation of metabolically produced acids with elevated plasma chloride, hyperchloremic metabolic ACIDOSIS. Defective renal acidification of URINE (proximal tubules) or low renal acid excretion (distal tubules) can lead to complications such as HYPOKALEMIA, hypercalcinuria with NEPHROLITHIASIS and NEPHROCALCINOSIS, and RICKETS.Blood Proteins: Proteins that are present in blood serum, including SERUM ALBUMIN; BLOOD COAGULATION FACTORS; and many other types of proteins.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Click Chemistry: Organic chemistry methodology that mimics the modular nature of various biosynthetic processes. It uses highly reliable and selective reactions designed to "click" i.e., rapidly join small modular units together in high yield, without offensive byproducts. In combination with COMBINATORIAL CHEMISTRY TECHNIQUES, it is used for the synthesis of new compounds and combinatorial libraries.Visual Fields: The total area or space visible in a person's peripheral vision with the eye looking straightforward.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, and practicability of these interventions in individual cases or series.Alkynes: Hydrocarbons with at least one triple bond in the linear portion, of the general formula Cn-H2n-2.Double-Blind Method: A method of studying a drug or procedure in which both the subjects and investigators are kept unaware of who is actually getting which specific treatment.Internet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Algorithms: A procedure consisting of a sequence of algebraic formulas and/or logical steps to calculate or determine a given task.Spherocytes: Small, abnormal spherical red blood cells with more than the normal amount of hemoglobin.International Classification of Diseases: A system of categories to which morbid entries are assigned according to established criteria. Included is the entire range of conditions in a manageable number of categories, grouped to facilitate mortality reporting. It is produced by the World Health Organization (From ICD-10, p1). The Clinical Modifications, produced by the UNITED STATES DEPT. OF HEALTH AND HUMAN SERVICES, are larger extensions used for morbidity and general epidemiological purposes, primarily in the U.S.Databases, Factual: Extensive collections, reputedly complete, of facts and data garnered from material of a specialized subject area and made available for analysis and application. The collection can be automated by various contemporary methods for retrieval. The concept should be differentiated from DATABASES, BIBLIOGRAPHIC which is restricted to collections of bibliographic references.Clinical Coding: Process of substituting a symbol or code for a term such as a diagnosis or procedure. (from Slee's Health Care Terms, 3d ed.)Ventricular Outflow Obstruction: Occlusion of the outflow tract in either the LEFT VENTRICLE or the RIGHT VENTRICLE of the heart. This may result from CONGENITAL HEART DEFECTS, predisposing heart diseases, complications of surgery, or HEART NEOPLASMS.Thrombocytosis: Increased numbers of platelets in the peripheral blood. (Dorland, 27th ed)Pulmonary Valve: A valve situated at the entrance to the pulmonary trunk from the right ventricle.Tetralogy of Fallot: A combination of congenital heart defects consisting of four key features including VENTRICULAR SEPTAL DEFECTS; PULMONARY STENOSIS; RIGHT VENTRICULAR HYPERTROPHY; and a dextro-positioned AORTA. In this condition, blood from both ventricles (oxygen-rich and oxygen-poor) is pumped into the body often causing CYANOSIS.Parvovirus B19, Human: The type species of ERYTHROVIRUS and the etiological agent of ERYTHEMA INFECTIOSUM, a disease most commonly seen in school-age children.Parvoviridae Infections: Virus infections caused by the PARVOVIRIDAE.Erythema Infectiosum: Contagious infection with human B19 Parvovirus most commonly seen in school age children and characterized by fever, headache, and rashes of the face, trunk, and extremities. It is often confused with rubella.Parvovirus: A genus of the family PARVOVIRIDAE, subfamily PARVOVIRINAE, infecting a variety of vertebrates including humans. Parvoviruses are responsible for a number of important diseases but also can be non-pathogenic in certain hosts. The type species is MINUTE VIRUS OF MICE.Parvoviridae: A family of very small DNA viruses containing a single molecule of single-stranded DNA and consisting of two subfamilies: PARVOVIRINAE and DENSOVIRINAE. They infect both vertebrates and invertebrates.Common Bile Duct Diseases: Diseases of the COMMON BILE DUCT including the AMPULLA OF VATER and the SPHINCTER OF ODDI.Bilirubin: A bile pigment that is a degradation product of HEME.Sphincterotomy, Endoscopic: Incision of Oddi's sphincter or Vater's ampulla performed by inserting a sphincterotome through an endoscope (DUODENOSCOPE) often following retrograde cholangiography (CHOLANGIOPANCREATOGRAPHY, ENDOSCOPIC RETROGRADE). Endoscopic treatment by sphincterotomy is the preferred method of treatment for patients with retained or recurrent bile duct stones post-cholecystectomy, and for poor-surgical-risk patients that have the gallbladder still present.Cholangiopancreatography, Endoscopic Retrograde: Fiberoptic endoscopy designed for duodenal observation and cannulation of VATER'S AMPULLA, in order to visualize the pancreatic and biliary duct system by retrograde injection of contrast media. Endoscopic (Vater) papillotomy (SPHINCTEROTOMY, ENDOSCOPIC) may be performed during this procedure.Molecular Sequence Data: Descriptions of specific amino acid, carbohydrate, or nucleotide sequences which have appeared in the published literature and/or are deposited in and maintained by databanks such as GENBANK, European Molecular Biology Laboratory (EMBL), National Biomedical Research Foundation (NBRF), or other sequence repositories.Nucleotides: The monomeric units from which DNA or RNA polymers are constructed. They consist of a purine or pyrimidine base, a pentose sugar, and a phosphate group. (From King & Stansfield, A Dictionary of Genetics, 4th ed)