Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0917816 (mental retardation)
 15,867 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Many individuals with mental retardation exhibit chronic aberrant behaviors (CABs) that includes hyperactive, stereotyped, aggressive, and self-injurious behaviors. Brain imaging studies have found that several of these individuals have abnormalities in their dopaminergic neurotransmitter systems that are thought to be responsible in part, for the development of these behaviors. The present study evaluated the effects of a selective dopamine re-uptake blocker, GBR-12909 in three animal models of varying striatal dopamine concentrations. The three animal models included the neonatal 6-hydroxydopamine (6-OHDA)-lesioned rat, a model of dopamine neuronal depletion, the prenatal methylazoxymethanol (MAM)-exposed rat, a model of hyper-dopaminergic innervation and control rats, a model of normal dopaminergic function. The animals were given five daily injections of GBR-12909 and videotaped observations were conducted immediately following the injections and 6h later. The results of the study indicate that the MAM-treated rats exhibited more hyperactive behaviors than either the 6-OHDA or the control animals in response to the GBR-12909 injections. However, the 6-OHDA and control rats exhibited more self-injurious behaviors than the MAM rats. Interestingly, the topography of the self-injurious behavior exhibited differed from that we have previously observed in 6-OHDA lesioned rats following dopamine agonists and resembles the mouthing behaviors seen in some individuals with mental retardation, in particular those with Rett syndrome. These findings indicate the models of varying dopaminergic function interact differently with a dopamine re-uptake blocker than dopamine agonists and that the partially dopamine depleted model may model the behaviors seen in individuals with Rett syndrome.
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PMID:Dopamine re-uptake inhibitor GBR-12909 induction of aberrant behaviors in animal models of dopamine dysfunction. 1217 69

Contingent shock (CS) has been used in a number of studies to suppress health-threatening self-injurious behavior of individuals with mental retardation and autism. As sustained suppression is an issue of concern, research into procedural variables of CS is needed. In this study, clinical evidence was used to infer a variable that might be of relevance for the application of clinical contingent shock, that is, to assess the effect of single versus repeated shock at a specific location on the body. With pain intensity and startle response as dependent variables, shocks were administered to 48 healthy volunteers. Electric shocks were identical to those that used in clinical practice. The second shock in succession to the same location of the body produced higher pain intensity ratings than the first shock and that the third shock in succession to the same location of the body produced higher pain intensity ratings than the second shock in succession. Startle responses, however, failed to be affected in this direction. The latter result is consistent with a previous study. Our data suggest that repeated shock to the same location is likely to be more effective to establish suppression than repeated shock to different locations.
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PMID:Effects of single and repeated shock on perceived pain and startle response in healthy volunteers. 1236 52

Self-restraint is often reported in individuals with mental retardation who show self-injurious behavior (SIB). In this study, the phenomenology and prevalence of self-restraint in individuals showing self-injury and wearing protective devices and those showing self-injury but not wearing protective devices were compared. A high prevalence of self-restraint in the whole sample of individuals showing self-injury was identified (67/88, 76.1%), and self-restraint was more prevalent in a group showing self-injury but not wearing protective devices (43/47, 91.5%) than in a group showing self-injury and wearing protective devices (24/41, 58.5%). Individuals not wearing protective devices showed a greater number of topographies of self-restraint than those who did wear them. Results are discussed with reference to the purely topographical definition of self-restraint employed and the potential equivalence of protective devices and self-restraint.
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PMID:Phenomenology of self-restraint. 1256 40

Behavioral side effects associated with clonazepam may include agitation, aggression, hyperactivity, irritability, property destruction, and temper tantrums. These side effects may be inadvertently confused with other behavioral or psychiatric conditions, especially if exacerbation of existing challenging behavior occurs. This report describes an individual with mental retardation who experienced behavioral exacerbation associated with clonazepam prescribed at 2 mg/day (0.02 mg/kg/day) to treat aggression, self-injurious behavior, property destruction, and screaming, which was measured with a 15-minute partial interval recording measurement method. When clonazepam was reduced and discontinued, these behaviors significantly decreased from 3.1% of intervals (95% confidence band = 1.6% to 4.6%) to 0.1% of intervals (95% confidence band = 0% to 0.1%). Indicators suggesting review by appropriate medical personnel for possible clonazepam behavioral side effects are provided.
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PMID:Brief report: clonazepam behavioral side effects with an individual with mental retardation. 1290 37

Multi-sensory stimulation provided in a Snoezelen room is being used increasingly for individuals with mental retardation and mental illness to facilitate relaxation, provide enjoyment, and inhibit behavioral challenges. We observed aggressive and self-injurious behavior in three groups of 15 individuals with severe or profound mental retardation and mental illness before, during, and after being in a Snoezelen room. All participants were receiving psychotropic medication for their mental illness and function-derived behavioral interventions for aggression, self-injury, or both. Using a repeated measures counterbalanced design, each group of participants was rotated through three experimental conditions: Activities of Daily Living (ADL) skills training, Snoezelen, and Vocational skills training. All other treatment and training activities specified in each individual's person-centered plan were continued during the 10-week observational period. Both aggression and self-injury were lowest when the individuals were in a Snoezelen room, followed by Vocational skills training and ADL skills training. The levels in the Snoezelen room were significantly lower than in both the other conditions for aggression but only in ADL skills training for self-injury. The difference in levels before and after Snoezelen were statistically significant with self-injury but not with aggression. The order of conditions showed no significant effect on either behavior. Snoezelen may provide an effective context for reducing the occurrence of self-injury and aggression.
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PMID:Effects of Snoezelen room, Activities of Daily Living skills training, and Vocational skills training on aggression and self-injury by adults with mental retardation and mental illness. 1513 93

People with mental retardation, autism, and related developmental disabilities who self-injure are treated with a wide array of behavioral techniques and psychotropic medications. Despite numerous reports documenting short-term and some long-term changes in self-injury associated with the opiate antagonist naltrexone hydrochloride, no quantitative review of its efficacy has been reported. We conducted a quantitative synthesis of the peer-reviewed published literature from 1983 to 2003 documenting the use of naltrexone for the treatment of self-injurious behavior (SIB). Individual-level results were analyzed given subject and study characteristics. A sample of 27 research articles involving 86 subjects with self-injury was reviewed. Eighty percent of subjects were reported to improve relative to baseline (i.e., SIB reduced) during naltrexone administration and 47% of subjects SIB was reduced by 50% or greater. In studies reporting dose levels in milligrams, males were more likely than females to respond. No significant relations were found between treatment outcomes and autism status or form of self-injury. Results are discussed with respect to future efficacy work related to study outcomes and the pharmacological treatment of self-injury.
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PMID:Self-injurious behavior and the efficacy of naltrexone treatment: a quantitative synthesis. 1561 82

One of the most serious and difficult-to-treat conditions in child and adolescent psychiatry is self-injurious behavior (SIB). SIB can be associated with a number of psychiatric disorders, including mental retardation, schizophrenia, borderline personality disorder, pervasive developmental disorders, stereotypic movement disorder, and Tourette's Disorder. A variety of neurosurgical procedures have been used to treat both intractable SIB and severe Tourette's Disorder. Understandably, there are few reports concerning psychosurgery in children and adolescents for any condition or disorder. This report describes the use of cingulotomy and subsequent limbic leucotomy in an adolescent boy with Tourette's Disorder for SIB. His repetitive and medically serious SIB and failure of all other treatments prompted this intervention after careful, comprehensive review and discussion. Following the second surgery, the severity and frequency of his SIB were reduced.
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PMID:Psychosurgery for self-injurious behavior in Tourette's disorder. 1566 44

Differences in subscale scores on the questions about behavioral function (QABF) were assessed for participants identified with pica, rumination, food stealing, food refusal, and mealtime behavior problems (e.g., aggression, self-injurious behavior). The QABF was administered to informants for 125 individuals identified with problematic feeding behaviors and mental retardation primarily in the severe to profound range. Results of the nonparametric analyses yielded significant differences across the escape, nonsocial, physical, and tangible subscales of the QABF. Behavior functions most commonly associated with problematic feeding behaviors were identified. The results extend upon previous literature describing behavioral function of feeding problems for those with mental retardation.
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PMID:The behavioral function of feeding problems as assessed by the questions about behavioral function (QABF). 1576 32

Lesch-Nyhan disease (LND) is an inborn error of purine metabolism caused by defective activity of the enzyme hypoxanthine guanine phosphoribosyl transferase (HPRT, EC 2.4.2.8), resulting from mutation in the corresponding gene on the long arm of the X chromosome (Xq26). The classic phenotype occurs almost exclusively in males and is characterized by hyperuricemia, mental retardation, severe dystonia, and self-injurious behavior. Heterozygous carrier females are usually clinically normal. However, a small number of clinically affected females have been described. In all previous cases there was a mutation in one HPRT allele and non-random inactivation of the X chromosome carrying the normal HPRT gene. We have analyzed a female MZ twin pair discordant for Lesch-Nyhan disease. The mother and both twins are heterozygous carriers of a HPRT splicing mutation (IVS8 + 4A > G; c.609 + 4A > G) and all three express the mutant allele at similar frequencies in peripheral blood T cells. The mother and one sister are clinically normal. In the affected twin, the clinical phenotype is classical for Lesch-Nyhan disease, despite the fact that HPRT activity in the blood was also normal. X inactivation analysis showed a skewed pattern in the fibroblasts of the affected twin sister, with the X chromosome carrying the normal HPRT allele preferentially inactivated. As in many other reported cases of X-linked diseases, the discordant phenotype of the two monozygous twin sisters suggests that the process responsible for monozygotic twinning can trigger skewed X inactivation.
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PMID:Lesch-Nyhan disease in a female with a clinically normal monozygotic twin. 1586 83

Lesch-Nyhan disease (LND) is a rare disorder caused by a defect of an enzyme in the purine salvage pathway, hypoxanthine phosphoribosyl transferase (HPRT). It is still unknown how the metabolic defect translates into the complex neuropsychiatric phenotype characterized by self-injurious behavior, dystonia and mental retardation. There are abnormalities in purine and pyrimidine nucleotide content in HPRT-deficient cells. We hypothesized that altered nucleotide concentrations in HPRT deficiency change G-protein-mediated signal transduction. Therefore, our original study aim was to examine the high-affinity GTPase activity of G-proteins in membranes from primary human skin and immortalized mouse skin fibroblasts, rat B103 neuroblastoma cells and mouse Neuro-2a neuroblastoma cells. Unexpectedly, in membranes from human fibroblasts, B103- and Neuro-2a cells, V(max) of low-affinity nucleoside 5'-triphosphatase (NTPase) activities was decreased up to 7-fold in HPRT deficiency. In contrast, in membranes from mouse fibroblasts, HPRT deficiency increased NTPase activity up to 4-fold. The various systems analyzed differed from each other in terms of K(m) values for NTPs, absolute V(max) values and K(i) values for nucleoside 5'-[beta,gamma-imido]triphosphates. Our data show that altered membrane NTPase activity is a biochemical hallmark of HPRT deficiency, but species and cell-type differences have to be considered. Thus, future studies on biochemical changes in LND should be conducted in parallel in several HPRT-deficient systems.
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PMID:Altered membrane NTPase activity in Lesch-Nyhan disease fibroblasts: comparison with HPRT knockout mice and HPRT-deficient cell lines. 1593 74


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