Michael B Brimacombe

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Autism spectrum disorders (ASD) are manifest as impairments in social interaction, language and speech development, and the appearance of repetitive behaviors with restricted interests. Motor impairments in individuals with ASD have been categorized as "associated symptoms". The objective of this study was to describe the prevalence of motor deficits in(More)
Leukocyte telomere length (LTL) is ostensibly a biomarker of human aging. Cross-sectional analyses have found that LTL is relatively short in a host of aging-related diseases. These studies have also provided indirect estimates of age-dependent LTL shortening. In this paper, the authors report findings of the first comprehensive longitudinal study of 450(More)
OBJECTIVE Genetic polymorphisms of the dopamine neurotransmitter system have been identified in attention deficit hyperactivity disorder (ADHD). Since stimulant medications act through this system, we sought to determine if the 48 base pair VNTR polymorphism (7- repeat allele) of dopamine receptor gene DRD4 predicts methylphenidate responsiveness. METHODS(More)
Leukocyte telomere length (LTL) is a complex genetic trait. It shortens with age and is associated with a host of aging-related disorders. Recent studies have observed that offspring of older fathers have longer LTLs. We explored the relation between paternal age and offspring's LTLs in 4 different cohorts. Moreover, we examined the potential cause of the(More)
As a screening tool to identify symptoms of autonomic dysfunction, the Pediatric Autonomic Symptoms Scale was administered to parents of children with familial dysautonomia, autism spectrum disorders, and age-matched controls. The total scores for the presence of symptoms were compared among the 3 groups for each section and overall. The Pediatric Autonomic(More)
It is believed that gene by environmental interactions contribute to the pathogenesis of autism spectrum disorders (ASD). We hypothesize that ASD are associated with early and repeated exposures to any of a number of toxicants or mixtures of toxicants. It is the cumulative effects of these repeated exposures acting upon genetically susceptible individuals(More)
Many of the clinical symptoms of autism suggest autonomic dysfunction. The aim of this study was to measure baseline cardiovascular autonomic function in children with autism using the NeuroScope, a device that can measure this brainstem function in real-time. Resting cardiac vagal tone (CVT), cardiac sensitivity to baroreflex (CSB), mean arterial blood(More)
Individuals with autism spectrum disorder are heterogeneous in clinical presentation, concurrent disorders, and developmental outcomes. This study characterized the clinical co-occurrences and potential subgroups in 160 children with autism spectrum disorders who presented to The Autism Center between 1999 and 2003. Medical and psychiatric co-occurrences(More)
Mutations that inhibit the insulin-like growth factor-1 (IGF-1) extend the lifespan of worms, flies and mice. However, it appears that relatively low circulating levels of IGF-1 in humans are associated with aging-related diseases and diminished longevity. As leukocyte telomere length (LTL) is ostensibly a biomarker of human aging, we examined the(More)
PURPOSE When neural circuits are damaged in adulthood, regenerating and sprouting processes must distinguish appropriate targets to recreate the normal circuitry. We tested the ability of adult nerve cells to target specific cells in culture using the retina as a model system. METHODS Under sterile culture conditions, retinal cells, isolated from tiger(More)