Thiamine Deficiency: A nutritional condition produced by a deficiency of THIAMINE in the diet, characterized by anorexia, irritability, and weight loss. Later, patients experience weakness, peripheral neuropathy, headache, and tachycardia. In addition to being caused by a poor diet, thiamine deficiency in the United States most commonly occurs as a result of alcoholism, since ethanol interferes with thiamine absorption. In countries relying on polished rice as a dietary staple, BERIBERI prevalence is very high. (From Cecil Textbook of Medicine, 19th ed, p1171)Thiamine: 3-((4-Amino-2-methyl-5-pyrimidinyl)methyl)-5-(2- hydroxyethyl)-4-methylthiazolium chloride.Pyrithiamine: A thiamine antagonist due to its inhibition of thiamine pyrophosphorylation. It is used to produce thiamine deficiency.Transketolase: An enzyme of the transferase class that catalyzes the conversion of sedoheptulose 7-phosphate and D-glyceraldehyde 3-phosphate to D-ribose 5-phosphate and D-xylulose 5-phosphate in the PENTOSE PHOSPHATE PATHWAY. (Dorland, 27th ed) EC Encephalopathy: An acute neurological disorder characterized by the triad of ophthalmoplegia, ataxia, and disturbances of mental activity or consciousness. Eye movement abnormalities include nystagmus, external rectus palsies, and reduced conjugate gaze. THIAMINE DEFICIENCY and chronic ALCOHOLISM are associated conditions. Pathologic features include periventricular petechial hemorrhages and neuropil breakdown in the diencephalon and brainstem. Chronic thiamine deficiency may lead to KORSAKOFF SYNDROME. (Adams et al., Principles of Neurology, 6th ed, pp1139-42; Davis & Robertson, Textbook of Neuropathology, 2nd ed, pp452-3)Beriberi: A disease caused by a deficiency of thiamine (vitamin B1) and characterized by polyneuritis, cardiac pathology, and edema. The epidemic form is found primarily in areas in which white (polished) rice is the staple food, as in Japan, China, the Philippines, India, and other countries of southeast Asia. (Dorland, 27th ed)Korsakoff Syndrome: An acquired cognitive disorder characterized by inattentiveness and the inability to form short term memories. This disorder is frequently associated with chronic ALCOHOLISM; but it may also result from dietary deficiencies; CRANIOCEREBRAL TRAUMA; NEOPLASMS; CEREBROVASCULAR DISORDERS; ENCEPHALITIS; EPILEPSY; and other conditions. (Adams et al., Principles of Neurology, 6th ed, p1139)Thiamine Pyrophosphate: The coenzyme form of Vitamin B1 present in many animal tissues. It is a required intermediate in the PYRUVATE DEHYDROGENASE COMPLEX and the KETOGLUTARATE DEHYDROGENASE COMPLEX.Oxythiamine: Thiamine antagonist, antimetabolite.Amprolium: A veterinary coccidiostat that interferes with THIAMINE metabolism.Thiamine Monophosphate: Thiamine dihydrogen phosphate ester. The monophosphate ester of thiamine. Synonyms: monophosphothiamine; vitamin B1 monophosphate.Alcohol Amnestic Disorder: A mental disorder associated with chronic ethanol abuse (ALCOHOLISM) and nutritional deficiencies characterized by short term memory loss, confabulations, and disturbances of attention. (Adams et al., Principles of Neurology, 6th ed, p1139)Diencephalon: The paired caudal parts of the PROSENCEPHALON from which the THALAMUS; HYPOTHALAMUS; EPITHALAMUS; and SUBTHALAMUS are derived.Ketoglutarate Dehydrogenase ComplexLaosThiamin Pyrophosphokinase: An enzyme that catalyzes the formation of thiamine pyrophosphate from ATP and thiamine. EC Drugs that are chemically similar to naturally occurring metabolites, but differ enough to interfere with normal metabolic pathways. (From AMA Drug Evaluations Annual, 1994, p2033)Amnesia: Pathologic partial or complete loss of the ability to recall past experiences (AMNESIA, RETROGRADE) or to form new memories (AMNESIA, ANTEROGRADE). This condition may be of organic or psychologic origin. Organic forms of amnesia are usually associated with dysfunction of the DIENCEPHALON or HIPPOCAMPUS. (From Adams et al., Principles of Neurology, 6th ed, pp426-7)Clinical Enzyme Tests: Analyses for a specific enzyme activity, or of the level of a specific enzyme that is used to assess health and disease risk, for early detection of disease or disease prediction, diagnosis, and change in disease status.Polyneuropathies: Diseases of multiple peripheral nerves simultaneously. Polyneuropathies usually are characterized by symmetrical, bilateral distal motor and sensory impairment with a graded increase in severity distally. The pathological processes affecting peripheral nerves include degeneration of the axon, myelin or both. The various forms of polyneuropathy are categorized by the type of nerve affected (e.g., sensory, motor, or autonomic), by the distribution of nerve injury (e.g., distal vs. proximal), by nerve component primarily affected (e.g., demyelinating vs. axonal), by etiology, or by pattern of inheritance.Cats: The domestic cat, Felis catus, of the carnivore family FELIDAE, comprising over 30 different breeds. The domestic cat is descended primarily from the wild cat of Africa and extreme southwestern Asia. Though probably present in towns in Palestine as long ago as 7000 years, actual domestication occurred in Egypt about 4000 years ago. (From Walker's Mammals of the World, 6th ed, p801)Vitamin B 12 Deficiency: A nutritional condition produced by a deficiency of VITAMIN B 12 in the diet, characterized by megaloblastic anemia. Since vitamin B 12 is not present in plants, humans have obtained their supply from animal products, from multivitamin supplements in the form of pills, and as additives to food preparations. A wide variety of neuropsychiatric abnormalities is also seen in vitamin B 12 deficiency and appears to be due to an undefined defect involving myelin synthesis. (From Cecil Textbook of Medicine, 19th ed, p848)Cat Diseases: Diseases of the domestic cat (Felis catus or F. domesticus). This term does not include diseases of the so-called big cats such as CHEETAHS; LIONS; tigers, cougars, panthers, leopards, and other Felidae for which the heading CARNIVORA is used.Vitamin B 6: VITAMIN B 6 refers to several PICOLINES (especially PYRIDOXINE; PYRIDOXAL; & PYRIDOXAMINE) that are efficiently converted by the body to PYRIDOXAL PHOSPHATE which is a coenzyme for synthesis of amino acids, neurotransmitters (serotonin, norepinephrine), sphingolipids, and aminolevulinic acid. During transamination of amino acids, pyridoxal phosphate is transiently converted into PYRIDOXAMINE phosphate. Although pyridoxine and Vitamin B 6 are still frequently used as synonyms, especially by medical researchers, this practice is erroneous and sometimes misleading (EE Snell; Ann NY Acad Sci, vol 585 pg 1, 1990). Most of vitamin B6 is eventually degraded to PYRIDOXIC ACID and excreted in the urine.Periaqueductal Gray: Central gray matter surrounding the CEREBRAL AQUEDUCT in the MESENCEPHALON. Physiologically it is probably involved in RAGE reactions, the LORDOSIS REFLEX; FEEDING responses, bladder tonus, and pain.Acidosis, Lactic: Acidosis caused by accumulation of lactic acid more rapidly than it can be metabolized. It may occur spontaneously or in association with diseases such as DIABETES MELLITUS; LEUKEMIA; or LIVER FAILURE.Diffusion Magnetic Resonance Imaging: A diagnostic technique that incorporates the measurement of molecular diffusion (such as water or metabolites) for tissue assessment by MRI. The degree of molecular movement can be measured by changes of apparent diffusion coefficient (ADC) with time, as reflected by tissue microstructure. Diffusion MRI has been used to study BRAIN ISCHEMIA and tumor response to treatment.Amino Acids, Branched-Chain: Amino acids which have a branched carbon chain.Leucine: An essential branched-chain amino acid important for hemoglobin formation.Magnetic Resonance Imaging: Non-invasive method of demonstrating internal anatomy based on the principle that atomic nuclei in a strong magnetic field absorb pulses of radiofrequency energy and emit them as radiowaves which can be reconstructed into computerized images. The concept includes proton spin tomographic techniques.Heart Failure: A heterogeneous condition in which the heart is unable to pump out sufficient blood to meet the metabolic need of the body. Heart failure can be caused by structural defects, functional abnormalities (VENTRICULAR DYSFUNCTION), or a sudden overload beyond its capacity. Chronic heart failure is more common than acute heart failure which results from sudden insult to cardiac function, such as MYOCARDIAL INFARCTION.Abdominal Pain: Sensation of discomfort, distress, or agony in the abdominal region.Anemia, Megaloblastic: A disorder characterized by the presence of ANEMIA, abnormally large red blood cells (megalocytes or macrocytes), and MEGALOBLASTS.Anemia, Macrocytic: Anemia characterized by larger than normal erythrocytes, increased mean corpuscular volume (MCV) and increased mean corpuscular hemoglobin (MCH).Folic Acid Deficiency: A nutritional condition produced by a deficiency of FOLIC ACID in the diet. Many plant and animal tissues contain folic acid, abundant in green leafy vegetables, yeast, liver, and mushrooms but destroyed by long-term cooking. Alcohol interferes with its intermediate metabolism and absorption. Folic acid deficiency may develop in long-term anticonvulsant therapy or with use of oral contraceptives. This deficiency causes anemia, macrocytic anemia, and megaloblastic anemia. It is indistinguishable from vitamin B 12 deficiency in peripheral blood and bone marrow findings, but the neurologic lesions seen in B 12 deficiency do not occur. (Merck Manual, 16th ed)Megaloblasts: Red blood cell precursors, corresponding to ERYTHROBLASTS, that are larger than normal, usually resulting from a FOLIC ACID DEFICIENCY or VITAMIN B 12 DEFICIENCY.Anemia, Pernicious: A megaloblastic anemia occurring in children but more commonly in later life, characterized by histamine-fast achlorhydria, in which the laboratory and clinical manifestations are based on malabsorption of vitamin B 12 due to a failure of the gastric mucosa to secrete adequate and potent intrinsic factor. (Dorland, 27th ed)Imino Furanoses: Five-carbon furanose sugars in which the OXYGEN is replaced by a NITROGEN atom.Amnesia, Retrograde: Loss of the ability to recall information that had been previously encoded in memory prior to a specified or approximate point in time. This process may be organic or psychogenic in origin. Organic forms may be associated with CRANIOCEREBRAL TRAUMA; CEREBROVASCULAR ACCIDENTS; SEIZURES; DEMENTIA; and a wide variety of other conditions that impair cerebral function. (From Adams et al., Principles of Neurology, 6th ed, pp426-9)Amnesia, Anterograde: Loss of the ability to form new memories beyond a certain point in time. This condition may be organic or psychogenic in origin. Organically induced anterograde amnesia may follow CRANIOCEREBRAL TRAUMA; SEIZURES; ANOXIA; and other conditions which adversely affect neural structures associated with memory formation (e.g., the HIPPOCAMPUS; FORNIX (BRAIN); MAMMILLARY BODIES; and ANTERIOR THALAMIC NUCLEI). (From Memory 1997 Jan-Mar;5(1-2):49-71)Amnesia, Transient Global: A syndrome characterized by a transient loss of the ability to form new memories. It primarily occurs in middle aged or elderly individuals, and episodes may last from minutes to hours. During the period of amnesia, immediate and recent memory abilities are impaired, but the level of consciousness and ability to perform other intellectual tasks are preserved. The condition is related to bilateral dysfunction of the medial portions of each TEMPORAL LOBE. Complete recovery normally occurs, and recurrences are unusual. (From Adams et al., Principles of Neurology, 6th ed, pp429-30)Retention (Psychology): The persistence to perform a learned behavior (facts or experiences) after an interval has elapsed in which there has been no performance or practice of the behavior.Memory: Complex mental function having four distinct phases: (1) memorizing or learning, (2) retention, (3) recall, and (4) recognition. Clinically, it is usually subdivided into immediate, recent, and remote memory.Ketoglutaric Acids: A family of compounds containing an oxo group with the general structure of 1,5-pentanedioic acid. (From Lehninger, Principles of Biochemistry, 1982, p442)Dose-Response Relationship, Drug: The relationship between the dose of an administered drug and the response of the organism to the drug.New Zealand: A group of islands in the southwest Pacific. Its capital is Wellington. It was discovered by the Dutch explorer Abel Tasman in 1642 and circumnavigated by Cook in 1769. Colonized in 1840 by the New Zealand Company, it became a British crown colony in 1840 until 1907 when colonial status was terminated. New Zealand is a partly anglicized form of the original Dutch name Nieuw Zeeland, new sea land, possibly with reference to the Dutch province of Zeeland. (From Webster's New Geographical Dictionary, 1988, p842 & Room, Brewer's Dictionary of Names, 1992, p378)Magnesium Deficiency: A nutritional condition produced by a deficiency of magnesium in the diet, characterized by anorexia, nausea, vomiting, lethargy, and weakness. Symptoms are paresthesias, muscle cramps, irritability, decreased attention span, and mental confusion, possibly requiring months to appear. Deficiency of body magnesium can exist even when serum values are normal. In addition, magnesium deficiency may be organ-selective, since certain tissues become deficient before others. (Harrison's Principles of Internal Medicine, 12th ed, p1936)Magnesium: A metallic element that has the atomic symbol Mg, atomic number 12, and atomic weight 24.31. It is important for the activity of many enzymes, especially those involved in OXIDATIVE PHOSPHORYLATION.Magnesium Sulfate: A small colorless crystal used as an anticonvulsant, a cathartic, and an electrolyte replenisher in the treatment of pre-eclampsia and eclampsia. It causes direct inhibition of action potentials in myometrial muscle cells. Excitation and contraction are uncoupled, which decreases the frequency and force of contractions. (From AMA Drug Evaluations Annual, 1992, p1083)Muscle Cramp: A sustained and usually painful contraction of muscle fibers. This may occur as an isolated phenomenon or as a manifestation of an underlying disease process (e.g., UREMIA; HYPOTHYROIDISM; MOTOR NEURON DISEASE; etc.). (From Adams et al., Principles of Neurology, 6th ed, p1398)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)EncyclopediasDictionaries, MedicalDictionaries as Topic: Lists of words, usually in alphabetical order, giving information about form, pronunciation, etymology, grammar, and meaning.