Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025362 (mental retardation)
 15,878 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Follow-up studies of two siblings with mental retardation, progressive paraplegia and dementia were reported. 2. The brain and visceral organs of a patient (elder brother) who died recently were investigated histopathologically, electronmicroscopically and neurochemically. a. Moderate, diffuse demyelination occurred throughout the white matter of the central nervous system. b. Two abnormal materials were deposited in the white matter: one showed metachromasia containing sulfatide and another had staining characteristics of acid mucopolysaccharide histochemically. Electronmicroscopically, the former was a conglomerate of electron-dense materials of various degrees and the latter had a membrane-limited granular structure. The myocardium contained the same mucopolysaccharide material as that in the brain. c. Slight increase of sulfatide was found in the cerebral white matter. Arylsulfatase A activities were preserved in the brain as well as in the liver. Contents of hexosamine and uronic acid in the white matter were about three or five times as much as that of the controls. Electrophoresis on cellulose acetate membrane showed that acid glucopeptide was the main component of the mucopolysaccharide extracted from the brain.
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PMID:Atypical leukodystrophy with accumulations of sulfatide and mucopolysaccharide. 15 14

1. The pathogenesis of the mental retardation in phenylketonuria remains obscure. Leucocytes have proved of value in the study of other inborn errors of metabolism. The lymphocyte is a suitable model cell for the study of mammalian metabolism, because of its ability to divide in vitro in response to various stimuli. 2. We have examined the effects of phenylalanine, phenylpyruvate, phenyl-lactate and phenylacetate on the human leucocyte and the resting and phytohaemagglutinin-stimulated rabbit lymphocyte. 3. Phenylpyruvate and phenyl-lactate reduced acetate incorporation into leucocyte lipid by 38% and 48% respectively. Only phenyl-lactate reduced acetate incorporation into the resting and stimulated lymphocyte, by 20% and 34% respectively. 4. Glucose incorporation into leucocyte lipid was unaffected by phenylalanine, phenylpyruvate and phenyl-lactate. Only phenyl-lactate inhibited (46%) the production of CO2 from glucose. 5. Phenylalanine and leucine incorporation into trichloroacetic acid-insoluble material of resting and stimulated lymphocytes was inhibited by phenyl-lactate (10-42%), phenylpyruvate (27-57%) and phenylacetate (19-39%). 6. Uridine incorporation into resting and stimulated cells was inhibited by phenyl-lactate (22-26%), phenylpyruvate (42-52%) and phenylacetate (20%). 7. Thymidine incorporation into resting lymphocytes was reduced by phenyl-lactate, phenylpyruvate, phenylacetate and phenylalanine by 12-26%. Incorporation into the stimulated cell was inhibited by phenylpyruvate and phenyl-lactate (90%) and phenylacetate (66%). 8. Phenylalanine inhibited lymphocyte pyruvate kinase and phenylpyruvate inhibited citrate synthetase. 9. These results are compared with published data relating to experimental hyperphenylalaninaemia and the effects of these metabolites on nervous tissue in vitro.
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PMID:Effect of phenylalanine and its metabolites on the metabolism of leucocytes and lymphocytes. 123 28

To assess medroxyprogesterone acetate (DMPA) prescription practices in adolescent health care practices, an anonymous questionnaire was distributed to 160 American and Canadian physicians who attended 1991 meetings of either the society for Adolescent Medicine or the North American Society for Pediatric and Adolescent Gynecology. Of 54 (33.7%) physicians who responded, 33 (61.1%) reported prior prescription of an injectable progestin (DMPA) as a form of birth control. Of those, 15 (45.5%) had prescribed it to 10 or more adolescents. 12 (57%) pediatricians, but only 3 (25%) gynecologists, reported prescribing DMPA to 10 or more adolescents (p = 0.074). Female physicians were more likely to have prescribed DMPA to adolescents than male physicians (p = 0.009). Mental retardation was considered the strongest "potential indication" for DMPA administration by 48 physicians who responded to a 5-point Likert scale. This study suggests that physicians with interest or expertise in adolescent medicine are using DMPA as a form of birth control for selected women in spite of the lack of FDA approval. A centralized DMPA registry is suggested to monitor adverse outcomes in users.
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PMID:Use of injectable progestin (medroxyprogesterone acetate) in adolescent health care. 142 22

Methylmalonate (MMA) accumulates in the tissues of patients with methylmalonic acidaemia, who present severe neurological signs soon after birth and later mental retardation. Attempting to understand the pathophysiology of the disorder, we investigated the effects of MMA on brain glucose uptake, lactate release and CO2 production. Glucose uptake and lactate release were studied by incubating 40 microns wide brain prisms from 15-day-old rats in Krebs-Ringer bicarbonate buffer, pH 7.0, containing 5.0 mmol/L glucose and one of three concentrations of MMA (1.0, 2.5 and 5.0 mmol/L). Controls did not contain MMA in the incubation medium. MMA induced a significant increase of lactate production in a dose-dependent pattern that was proportional to glucose uptake by the brain prisms. We also studied the influence of MMA on brain CO2 production from [2-14C]glucose and [U-14C]acetate by incubating brain prisms in the same buffer in the presence of the substrates with (experimental groups) or without (controls) 5.0 mmol/L MMA. MMA significantly reduced CO2 formation from both substrates.
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PMID:Effect of methylmalonate on in vitro lactate release and carbon dioxide production by brain of suckling rats. 158 80

Rat brain contains substantial concentrations of free malonate (192 nmol/g wet weight) but origin and biological importance of the dicarboxylic acid are poorly understood. A dietary source has been excluded. A recently described malonyl-CoA decarboxylase deficiency is associated with malonic aciduria and clinical manifestations, including mental retardation. In an effort to study the metabolic origin of free malonate, several labeled acetyl-CoA precursors were administered by intracerebral injection. [2-14C]pyruvate or [1,5-14C]citrate produced radioactive glutamate but failed to label malonate. In contrast, [1-14C]acetate, [2-14C]acetate, and [1-14C]butyrate were converted to labeled glutamate and malonate after the same route of administration. The intracerebral injection of [1-14C]-beta-alanine as a precursor of malonic semialdehyde and possibly free malonate did not give rise to radioactivity in the dicarboxylate. The labeling pattern of malonic acid is compatible with the reaction sequence: acetyl-CoA----malonyl-CoA----malonate. The final step is thought to occur by transfer of the CoA-group from malonyl-CoA to succinate and/or acetoacetate. Labeling of malonate from acetate is most effective at the age of 7 days when the net concentration of the dicarboxylic acid in rat brain is still very low. At this age, butyrate was a better precursor of malonate than acetate. It is proposed that fatty acid oxidation provides the acetyl-CoA which functions as the precursor of free brain malonate. Compartmentation of malonate biosynthesis is likely because the acetyl-CoA precursors citrate and pyruvate are ineffective.
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PMID:The origin of free brain malonate. 167 5

Current research indicates the importance of synaptic number and structure in plastic processes such as development, learning and memory, and aging. As such, the examination of these neural features has become an important factor in research on human conditions such as mental retardation, aging and Alzheimer's disease. Synaptic research in human tissue typically involves delayed post-mortem fixation, therefore the current research was designed to examine the effect of post-mortem delay on synaptic number and structure in tissue stained with either routine osmium lead citrate/uranyl acetate (osmium) or ethanol phosphotungstic acid (EPTA). Results indicate that synaptic density shows either a gradual decline (EPTA) or an initial marked drop followed by a plateau (osmium) up to 10-15 h post-mortem depending on the stain used. The number of synaptic vesicles per synapse also undergoes a gradual decline. Measures of synaptic structure were more stable, with the primary change being an initial increase in the cross-sectional length of the synapse. Maximal height of the pre- and postsynaptic dense elements were not affected by post-mortem delay. The EPTA stain gave the best estimates of synaptic parameters with short post-mortem delays. These results indicate that different synaptic measures (and stains) show different responses to post-mortem fixation delay, and that experimental or statistical methods must be used to control for post-mortem effects.
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PMID:Quantifying synaptic number and structure: effects of stain and post-mortem delay. 169 64

Sexual offenses, particularly paraphilias, although infrequent, are committed by people with mental retardation. Their management poses clinical and ethical dilemmas. Available treatments were reviewed, especially the literature on the most effective agent, medroxyprogesterone acetate (MPA). A case history was presented of a young man with mild mental retardation who was successfully treated with MPA. The role of antiandrogen treatments of paraphilias among the mentally retarded population includes a consideration of informed consent and ethical aspects of treatment.
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PMID:Treatment of sexual offenses by persons with developmental disabilities. 182 55

Sibling cases of familial vitamin E deficiency accompanied by ataxia, polyneuropathy and mental retardation were reported. Case 1 was a 37-year-old male who developed progressive gait disturbance, deformity of the feet and head tremor from childhood, after normal delivery and development of early childhood. On physical examination, he had cataract, high arched palate and pes cavus. Neurological examination revealed mental retardation (WAIS 68), scanning speech, muscular atrophy of the face and extremities with predominance in the lower limbs, absent Achilles tendon reflex, disturbance of superficial and deep sensation predominant in distal limbs, and marked gait ataxia. Ataxia was both cerebellar and sensory in nature. Laboratory data of the blood showed no significant abnormalities including blood glucose and vitamin B12 except a markedly low level of serum vitamin E. The brain CT scan revealed severe cerebellar atrophy and marked dilatation of the cisterna magna and the subarachnoid space around the cerebellum. Motor nerve conduction velocity in the leg was decreased. Biopsy specimen from the quadriceps muscle showed neurogenic atrophy. Sural nerve biopsy revealed decrease in large myelinated fibers with axonal degeneration and regeneration. Oral administration of alpha-tocopherol acetate, 600 mg per day, diminished ataxia significantly. Based on lysosomal enzyme activity in leukocytes, clinical and laboratory examination, lipidosis or spinocerebellar degeneration was excluded. Chronic lipid malabsorption or beta lipoprotein deficiency which can cause decrease in vitamin E absorption, was not recognized. On oral loading with 2 g of alpha-tocopherol acetate, the decrease rate of serum vitamin E was normal. Consequently the low vitamin E was considered to have resulted from selective impairment of vitamin E absorption.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Familial idiopathic vitamin E deficiency associated with cerebellar atrophy]. 226 7

A minority of people with mental retardation have sexual behaviour which is socially unacceptable or which brings them into conflict with the law. Such behaviour may be the result of ignorance about sexual matters, often best managed by counselling or by a behavioural approach. There are a small number of men with mental retardation and aberrant sexual behaviour who benefit from the prescription of an antilibidinal drug. Treatment with an antilibidinal drug alone reduces the intensity of sexual drive but does not alter its direction; concurrent sexual counselling or psychotherapy is often indicated. The various antilibidinal medications available are reviewed, with particular attention to reports which have described the treatment of people with mental retardation. Of the antilibidinals currently used, medroxyprogesterone acetate and cyproterone acetate are those for which there is most evidence of efficacy. Cyproterone acetate is preferable because it has a specific antiandrogenic action and fewer adverse effects. There is a need for controlled studies of antilibidinal drugs, with clearly defined inclusion criteria and adequate measures of both behavioural and attitudinal change.
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PMID:Antilibidinal drugs and mental retardation: a review. 252 80

1. Inhibition of the rate of incorporation of [(35)S]methionine into protein by phenylalanine was more effective in 18-day-old than in 8-day-old or adult rat brain. 2. Among the subcellular fractions incorporation of [(35)S]methionine into myelin proteins was most inhibited in 18-day-old rat brain. 3. Transport of [(35)S]methionine and [(14)C]leucine into the brain acid-soluble pool was significantly decreased in 18-day-old rats by phenylalanine (2mg/g body wt.). The decrease of the two amino acids in the acid-soluble pool equalled the inhibition of their rate of incorporation into the protein. 4. Under identical conditions, entry of [(14)C]glycine into the brain acid-soluble pool and incorporation into protein and uptake of [(14)C]acetate into lipid was not affected by phenylalanine. 5. It is proposed that decreased myelin synthesis seen in hyperphenylalaninaemia or phenylketonuria may be due to alteration of the free amino acid pool in the brain during the vulnerable period of brain development. Amyelination may be one of many causes of mental retardation seen in phenylketonuria.
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PMID:Effect of phenylalanine on protein synthesis in the developing rat brain. 546 65


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