Pubmed du 24/08/13

Pubmed du jour

2013-08-24 12:03:50

1. Bateman C. {{Autism–mitigating a global epidemic}}. {S Afr Med J}. 2013; 103(5): 276-7.

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2. Bradley SJ. {{The importance of early intervention with children and youth in the autism spectrum}}. {J Can Acad Child Adolesc Psychiatry}. 2013; 22(3): 197-8.

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3. Duan XY, Jia FY, Jiang HY. {{[Relationship between vitamin D and autism spectrum disorder]}}. {Zhongguo Dang Dai Er Ke Za Zhi}. 2013; 15(8): 698-702.

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder, with multiple genetic and environmental risk factors. The interplay between genetic and environmental factors has become the subject of intensified research in the last several years. Vitamin D deficiency has recently been proposed as a possible environmental risk factor for ASD. Vitamin D has a unique role in brain homeostasis, embryogenesis and neurodevelopment, immunological modulation (including the brain’s immune system), antioxidation, antiapoptosis, neural differentiation and gene regulation. Children with ASD had significantly lower serum levels of 25-hydroxy vitamin D than healthy children.Therefore vitamin D deficiency during pregnancy and early childhood may be an environmental trigger for ASD.

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4. Garg SK, Lioy DT, Cheval H, McGann JC, Bissonnette JM, Murtha MJ, Foust KD, Kaspar BK, Bird A, Mandel G. {{Systemic Delivery of MeCP2 Rescues Behavioral and Cellular Deficits in Female Mouse Models of Rett Syndrome}}. {J Neurosci}. 2013; 33(34): 13612-20.

De novo mutations in the X-linked gene encoding the transcription factor methyl-CpG binding protein 2 (MECP2) are the most frequent cause of the neurological disorder Rett syndrome (RTT). Hemizygous males usually die of neonatal encephalopathy. Heterozygous females survive into adulthood but exhibit severe symptoms including microcephaly, loss of purposeful hand motions and speech, and motor abnormalities, which appear after a period of apparently normal development. Most studies have focused on male mouse models because of the shorter latency to and severity in symptoms, yet how well these mice mimic the disease in affected females is not clear. Very few therapeutic treatments have been proposed for females, the more gender-appropriate model. Here, we show that self-complementary AAV9, bearing MeCP2 cDNA under control of a fragment of its own promoter (scAAV9/MeCP2), is capable of significantly stabilizing or reversing symptoms when administered systemically into female RTT mice. To our knowledge, this is the first potential gene therapy for females afflicted with RTT.

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5. Kaland C, Swerts M, Krahmer E. {{Accounting for the listener: Comparing the production of contrastive intonation in typically-developing speakers and speakers with autism}}. {J Acoust Soc Am}. 2013; 134(3): 2182-96.

The present research investigates what drives the prosodic marking of contrastive information. For example, a typically developing speaker of a Germanic language like Dutch generally refers to a pink car as a « PINK car » (accented words in capitals) when a previously mentioned car was red. The main question addressed in this paper is whether contrastive intonation is produced with respect to the speaker’s or (also) the listener’s perspective on the preceding discourse. Furthermore, this research investigates the production of contrastive intonation by typically developing speakers and speakers with autism. The latter group is investigated because people with autism are argued to have difficulties accounting for another person’s mental state and exhibit difficulties in the production and perception of accentuation and pitch range. To this end, utterances with contrastive intonation are elicited from both groups and analyzed in terms of function and form of prosody using production and perception measures. Contrary to expectations, typically developing speakers and speakers with autism produce functionally similar contrastive intonation as both groups account for both their own and their listener’s perspective. However, typically developing speakers use a larger pitch range and are perceived as speaking more dynamically than speakers with autism, suggesting differences in their use of prosodic form.

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6. Kern JK, Haley BE, Geier DA, Sykes LK, King PG, Geier MR. {{Thimerosal exposure and the role of sulfation chemistry and thiol availability in autism}}. {Int J Environ Res Public Health}. 2013; 10(8): 3771-800.

Autism spectrum disorder (ASD) is a neurological disorder in which a significant number of the children experience a developmental regression characterized by a loss of previously acquired skills and abilities. Typically reported are losses of verbal, nonverbal, and social abilities. Several recent studies suggest that children diagnosed with an ASD have abnormal sulfation chemistry, limited thiol availability, and decreased glutathione (GSH) reserve capacity, resulting in a compromised oxidation/reduction (redox) and detoxification capacity. Research indicates that the availability of thiols, particularly GSH, can influence the effects of thimerosal (TM) and other mercury (Hg) compounds. TM is an organomercurial compound (49.55% Hg by weight) that has been, and continues to be, used as a preservative in many childhood vaccines, particularly in developing countries. Thiol-modulating mechanisms affecting the cytotoxicity of TM have been identified. Importantly, the emergence of ASD symptoms post-6 months of age temporally follows the administration of many childhood vaccines. The purpose of the present critical review is provide mechanistic insight regarding how limited thiol availability, abnormal sulfation chemistry, and decreased GSH reserve capacity in children with an ASD could make them more susceptible to the toxic effects of TM routinely administered as part of mandated childhood immunization schedules.

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7. Khatri N, Simpson KL, Lin RC, Paul IA. {{Lasting neurobehavioral abnormalities in rats after neonatal activation of serotonin 1A and 1B receptors: possible mechanisms for serotonin dysfunction in autistic spectrum disorders}}. {Psychopharmacology (Berl)}. 2013.

RATIONALE: Perinatal exposure of rats to selective serotonin reuptake inhibitors (SSRIs) produces sensory and social abnormalities paralleling those seen in autistic spectrum disorders (ASDs). However, the possible mechanism(s) by which this exposure produces behavioral abnormalities is unclear. OBJECTIVE: We hypothesized that the lasting effects of neonatal SSRI exposure are a consequence of abnormal stimulation of 5-HT1A and/or 5-HT1B receptors during brain development. We examined whether such stimulation would result in lasting sensory and social deficits in rats in a manner similar to SSRIs using both direct agonist stimulation of receptors as well as selective antagonism of these receptors during SSRI exposure. METHODS: Male and female rat pups were treated from postnatal days 8 to 21. In Experiment 1, pups received citalopram (20 mg/kg/day), saline, (+/-)-8-hydroxy-dipropylaminotetralin hydrobromide (8-OH-DPAT; 0.5 mg/kg/day) or 7-trifluoromethyl-4(4-methyl-1-piperazinyl)-pyrrolo[1,2-a]-quinoxaline dimaleate (CGS-12066B; 10 mg/kg/day). In Experiment 2, a separate cohort of pups received citalopram (20 mg/kg/day), or saline which was combined with either N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-2-pyridinylcyclo-hexanecarboxami de maleate (WAY-100635; 0.6 mg/kg/day) or N-[4-methoxy-3-(4-methyl-1-piperazinyl)phenyl]-2′-methyl-4′-(5-methyl-1,2,4-oxadi azol-3-yl)-1-1′-biphenyl-4-carboxamide (GR-127935; 6 mg/kg/day) or vehicle. Rats were then tested in paradigms designed to assess sensory and social response behaviors at different time points during development. RESULTS: Direct and indirect neonatal stimulation of 5-HT1A or 5-HT1B receptors disrupts sensory processing, produces neophobia, increases stereotypic activity, and impairs social interactions in manner analogous to that observed in ASD. CONCLUSION: Increased stimulation of 5-HT1A and 5-HT1B receptors plays a significant role in the production of lasting social and sensory deficits in adult animals exposed as neonates to SSRIs.

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8. Lyall K, Baker A, Hertz-Picciotto I, Walker CK. {{Infertility and Its Treatments in Association with Autism Spectrum Disorders: A Review and Results from the CHARGE Study}}. {Int J Environ Res Public Health}. 2013; 10(8): 3715-34.

Previous findings on relationships between infertility, infertility therapies, and autism spectrum disorders (ASD) have been inconsistent. The goals of this study are first, to briefly review this evidence and second, to examine infertility and its treatments in association with having a child with ASD in newly analyzed data. In review, we identified 14 studies published as of May 2013 investigating infertility and/or its treatments and ASD. Overall, prior results showed little support for a strong association, though some increases in risk with specific treatments were found; many limitations were noted. In new analyses of the CHildhood Autism Risk from Genetics and the Environment (CHARGE) population-based study, cases with autism spectrum disorder (ASD, n = 513) and controls confirmed to have typical development (n = 388) were compared with regard to frequencies of infertility diagnoses and treatments overall and by type. Infertility diagnoses and treatments were also grouped to explore potential underlying pathways. Logistic regression was used to obtain crude and adjusted odds ratios overall and, in secondary analyses, stratified by maternal age (>/=35 years) and diagnostic subgroups. No differences in infertility, infertility treatments, or hypothesized underlying pathways were found between cases and controls in crude or adjusted analyses. Numbers were small for rarer therapies and in subgroup analyses; thus the potential for modest associations in specific subsets cannot be ruled out. However, converging evidence from this and other studies suggests that assisted reproductive technology is not a strong independent risk factor for ASD. Recommendations for future studies of this topic are provided.

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9. Norsa L, Giacchero R, Labriola F, Vignoli A. {{Chronic Hyponatriemia Associated With Rett Syndrome}}. {Pediatr Neurol}. 2013.

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10. Rosania K. {{Cholesterol key in Rett syndrome}}. {Lab Anim (NY)}. 2013; 42(9): 309.

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11. Scherff A, Taylor M, Eley TC, Happe F, Charman T, Ronald A. {{What Causes Internalising Traits and Autistic Traits to Co-occur in Adolescence? A Community-Based Twin Study}}. {J Abnorm Child Psychol}. 2013.

Autism shows a high degree of comorbidity with anxiety disorders. Adolescence is a time of increased stress and vulnerability to internalising problems. This study addresses for the first time the degree of genetic and environmental overlap between autistic traits (total measure and subscales) and internalising traits in a community-based adolescent twin sample. Parents of 12-14-year-old twins (N = 3,232 pairs; 3,460 males, 3,004 females) reported on the twins’ internalising and autistic traits. Autistic trait subscales were created using principal component analysis. Bivariate twin model-fitting was conducted. Autistic and internalising traits correlated moderately (r = 0.30). Genetic influences on individual traits were substantial but genetic overlap between traits was moderate (genetic correlation: males = 0.30, females = 0.12). Shared environmental influences were low for internalising traits and moderate for autistic traits, and showed considerable overlap (shared environmental correlation: males = 0.53, females = 1). Nonshared environmental influences were moderate for internalising traits and low for autistic traits and showed low overlap. A multiple component solution was found for autistic traits and of the derived subscales, autistic-like ‘Social Unease’ showed the most phenotypic and genetic overlap with internalising traits.

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12. Uddin LQ, Supekar K, Menon V. {{Reconceptualizing functional brain connectivity in autism from a developmental perspective}}. {Front Hum Neurosci}. 2013; 7: 458.

While there is almost universal agreement amongst researchers that autism is associated with alterations in brain connectivity, the precise nature of these alterations continues to be debated. Theoretical and empirical work is beginning to reveal that autism is associated with a complex functional phenotype characterized by both hypo- and hyper-connectivity of large-scale brain systems. It is not yet understood why such conflicting patterns of brain connectivity are observed across different studies, and the factors contributing to these heterogeneous findings have not been identified. Developmental changes in functional connectivity have received inadequate attention to date. We propose that discrepancies between findings of autism related hypo-connectivity and hyper-connectivity might be reconciled by taking developmental changes into account. We review neuroimaging studies of autism, with an emphasis on functional magnetic resonance imaging studies of intrinsic functional connectivity in children, adolescents and adults. The consistent pattern emerging across several studies is that while intrinsic functional connectivity in adolescents and adults with autism is generally reduced compared with age-matched controls, functional connectivity in younger children with the disorder appears to be increased. We suggest that by placing recent empirical findings within a developmental framework, and explicitly characterizing age and pubertal stage in future work, it may be possible to resolve conflicting findings of hypo- and hyper-connectivity in the extant literature and arrive at a more comprehensive understanding of the neurobiology of autism.

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13. Usui S, Senju A, Kikuchi Y, Akechi H, Tojo Y, Osanai H, Hasegawa T. {{Presence of contagious yawning in children with autism spectrum disorder}}. {Autism Res Treat}. 2013; 2013: 971686.

Most previous studies suggest diminished susceptibility to contagious yawning in children with autism spectrum disorder (ASD). However, it could be driven by their atypical attention to the face. To test this hypothesis, children with ASD and typically developing (TD) children were shown yawning and control movies. To ensure participants’ attention to the face, an eye tracker controlled the onset of the yawning and control stimuli. Results demonstrated that both TD children and children with ASD yawned more frequently when they watched the yawning stimuli than the control stimuli. It is suggested therefore that the absence of contagious yawning in children with ASD, as reported in previous studies, might relate to their weaker tendency to spontaneously attend to others’ faces.

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14. White SW, Smith LA, Schry AR. {{Assessment of global functioning in adolescents with autism spectrum disorders: Utility of the Developmental Disability-Child Global Assessment Scale}}. {Autism}. 2013.

Assessment of global functioning is an important consideration in treatment outcome research; yet, there is little guidance on its evidence-based assessment for children with autism spectrum disorders. This study investigated the utility and validity of clinician-rated global functioning using the Developmental Disability-Child Global Assessment Scale in a sample of higher functioning adolescents with autism spectrum disorders and comorbid anxiety disorders enrolled in a randomized controlled trial (n = 30). Pretreatment Developmental Disability-Child Global Assessment Scale scores correlated with severity of autism spectrum disorders core symptoms (r = -.388, p = .034), pragmatic communication (r = .407, p = .032), and verbal ability (r = .449, p = .013) and did not correlate with severity of anxiety symptoms or with parent-reported adaptive behavior. Change in Developmental Disability-Child Global Assessment Scale scores during treatment was associated with autism spectrum disorders symptomatic improvement (r = .414, p = .040) and with improved general communication (r = .499, p = .013). Results support the importance of assessing global functioning in addition to symptom change and treatment response in clinical trials.

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