Danielle A. Baribeau

Is regular exercise a friend or foe of the aging immune system? A systematic review

Objective:The purpose of the current review is to synthesize the available evidence from prospective clinical trials that are relevant to the clinical question: “What, if any, are the effects of regular aerobic and/or resistance exercise on the immune system in healthy older adults?” Data Sources:Electronic databases were searched, using terms pertaining to immunology, exercise, and aging. Using the Ovid interface, the following databases were explored: Allied and Complimentary Medicine (AMED) (1985 to 2008), Cumulative Index to Nursing and Allied Health Literature (CINAHL) (1982 to 2008), all EBM Reviews (Cochrane DSR, ACP Journal Club, DARE, CCTR, CMR, HTA, and NHSEED), EMBASE (1980 to 2008), and MEDLINE (1950 to 2008). The MEDLINE database was searched a second time through the PubMed interface. Study Selection:Prospective controlled clinical trials were selected for review if they investigated the effects of an exercise intervention (minimum 4 weeks in duration) on an immune outcome measure in an older but otherwise healthy population. A total of 19 articles representing 17 trials were identified. Data Extraction:Quality assessment of the relevant articles was performed using the Jadad et al1 criteria. Data extraction was performed using a standardized instrument. Data regarding the participants, interventions, and laboratory and clinical immunologic outcomes were synthesized. Data Synthesis:Available data provide no clear evidence of acute or chronic effects of exercise on lymphocyte or natural killer (NK) cell numbers or phenotype (ie, surface markers)/activity, with 2 exceptions: (1) strength or endurance exercise may cause an acute transient elevation in circulating CD8+ T cells, and (2) regular aerobic exercise appears to enhance immunologic memory in the context of vaccination. The effects of strength training on NK cell activity are unclear. Furthermore, regular aerobic exercise appears to be associated with a reduction in chronic inflammation. Finally, no prospective controlled trials have clearly documented clinical immunologic benefits of regular exercise, which may well relate to underpowering of these studies. Conclusions:Overall, in healthy older adults, regular, particularly aerobic, exercise appears to be a friend of the immune system, helping to offset diminished adaptive responses and chronic inflammation. The possibility exists that particularly strenuous exercise may cause acute immunologic changes, such as diminished NK cell activity, which could predispose to infection in certain individuals. However, given the possible benefits of regular exercise on the immune system and the many definite benefits on other systems, the evidence presented here should not dissuade practitioners from suggesting regular exercise to otherwise healthy older adults.

Oxytocin and vasopressin: linking pituitary neuropeptides and their receptors to social neurocircuits

Oxytocin and vasopressin are pituitary neuropeptides that have been shown to affect social processes in mammals. There is growing interest in these molecules and their receptors as potential precipitants of, and/or treatments for, social deficits in neurodevelopmental disorders, including autism spectrum disorder. Numerous behavioral-genetic studies suggest that there is an association between these peptides and individual social abilities; however, an explanatory model that links hormonal activity at the receptor level to complex human behavior remains elusive. The following review summarizes the known associations between the oxytocin and vasopressin neuropeptide systems and social neurocircuits in the brain. Following a micro- to macro- level trajectory, current literature on the synthesis and secretion of these peptides, and the structure, function and distribution of their respective receptors is first surveyed. Next, current models regarding the mechanism of action of these peptides on microcircuitry and other neurotransmitter systems are discussed. Functional neuroimaging evidence on the acute effects of exogenous administration of these peptides on brain activity is then reviewed. Overall, a model in which the local neuromodulatory effects of pituitary neuropeptides on brainstem and basal forebrain regions strengthen signaling within social neurocircuits proves appealing. However, these findings are derived from animal models; more research is needed to clarify the relevance of these mechanisms to human behavior and treatment of social deficits in neuropsychiatric disorders.

A Comparison of Neuroimaging Findings in Childhood Onset Schizophrenia and Autism Spectrum Disorder: A Review of the Literature

Background: Autism spectrum disorder (ASD) and childhood onset schizophrenia (COS) are pediatric neurodevelopmental disorders associated with significant morbidity. Both conditions are thought to share an underlying genetic architecture. A comparison of neuroimaging findings across ASD and COS with a focus on altered neurodevelopmental trajectories can shed light on potential clinical biomarkers and may highlight an underlying etiopathogenesis. Methods: A comprehensive review of the medical literature was conducted to summarize neuroimaging data with respect to both conditions in terms of structural imaging (including volumetric analysis, cortical thickness and morphology, and region of interest studies), white matter analysis (include volumetric analysis and diffusion tensor imaging) and functional connectivity. Results: In ASD, a pattern of early brain overgrowth in the first few years of life is followed by dysmaturation in adolescence. Functional analyses have suggested impaired long-range connectivity as well as increased local and/or subcortical connectivity in this condition. In COS, deficits in cerebral volume, cortical thickness, and white matter maturation seem most pronounced in childhood and adolescence, and may level off in adulthood. Deficits in local connectivity, with increased long-range connectivity have been proposed, in keeping with exaggerated cortical thinning. Conclusion: The neuroimaging literature supports a neurodevelopmental origin of both ASD and COS and provides evidence for dynamic changes in both conditions that vary across space and time in the developing brain. Looking forward, imaging studies which capture the early post natal period, which are longitudinal and prospective, and which maximize the signal to noise ratio across heterogeneous conditions will be required to translate research findings into a clinical environment.

The relationship between exercise and osteoarthritis in the elderly.

Objectives:To review within a prescribed evidence-based framework (1) the relationship between intermittent or lifelong physical activity and the subsequent onset or progression of osteoarthritis (OA) in later life and (2) the effect of structured exercise routines on the management of OA in the elderly. Data Sources:A systematic literature search of MEDLINE (1950 to April Week 2, 2008) and EMBASE (1980 to 2008 Week 16) was carried out using the Ovid interface. Relevant mapped terms addressing the identified objectives were combined and exploded according to a defined protocol. Study Selection:Studies that met relevancy criteria and were of high methodologic quality (prospective cohort studies for the risk factor component and systematic reviews and randomized controlled trials for the therapy component) were extracted and then hand searched for any additional studies. Final inclusion was based on agreement between two independent assessors, according to prescribed criteria. Any studies that were not in the English language, did not address the questions of interest in humans, or did not include a population that had at least a mean age of 55 years at the time of study termination, were excluded. Only land-based regimens were included in the therapy component of the review. Data Extraction:Pertinent information on subjects, risks, and outcomes (when assessing physical activity as a risk factor for OA in the elderly) and subjects, interventions, and outcomes (when evaluating the application of exercise in the management of OA in older persons) was extracted from the selected studies. Data Synthesis:Ten studies met entry criteria for examining the relationship between physical activity and the development or progression of OA. Likely because of study variations and differences in the nature, duration and intensities of exercise regimens, no clearcut consensus was apparent on whether or not physical activity was a risk factor for OA. Six scientific reviews and ten single blinded randomized controlled trials were included when evaluating the effect of exercise on OA management. Regardless of wide variability in the included studies, a majority demonstrated that structured exercise programs were effective in the management of older subjects with OA. Conclusions:Nuances of study design, differences in age and type of target populations, variability in the intensity, duration, and nature of physical activity in the respective studies, and lack of standardization in the way radiographic data are interpreted are among the factors that prevent consensus regarding the effect of physical activity on later development of OA. Similarly, there is considerable heterogeneity in the studies that assessed exercise in the treatment of OA. Nonetheless, there is substantive evidence in support of the benefits of one or another strength training or aerobic exercise regimen in the management of OA in middle-aged and elderly subjects.

Examining and Comparing Social Perception Abilities Across Childhood-Onset Neurodevelopmental Disorders

OBJECTIVE Several neurodevelopmental disorders are associated with social processing deficits. The objective of this study was to compare patterns of social perception abilities across obsessive-compulsive disorder (OCD), attention-deficit/hyperactivity disorder (ADHD), autism spectrum disorder (ASD), and control participants. METHOD A total of 265 children completed the Reading the Mind in the Eyes Test-Child Version (RMET). Parents or caregivers completed established trait/symptom scales. The predicted percentage of accuracy on the RMET was compared across disorders and by item difficulty and item valence (i.e., positive/negative/neutral mental states), then analyzed for associations with trait/symptom scores. RESULTS The percentage of correct RMET scores varied significantly between diagnostic groups (p < .0001). On pairwise group comparisons controlling for age and sex, children with ADHD and ASD scored lower than the other groups (p < .0001). When IQ was also controlled for in the model, participants with OCD performed better than controls (p < .001), although differences between other groups were less pronounced. Participants with ASD scored lowest on easy items. Those with ASD and ADHD scored significantly lower than other groups on items with positive valence (p < .01). Greater social communication impairment and hyperactivity/impulsivity, but not OCD traits/symptoms, were associated with lower scores on the RMET, irrespective of diagnosis. CONCLUSION Social perception abilities in neurodevelopmental disorders exist along a continuum. Children with ASD have the greatest deficits, whereas children with OCD may be hypersensitive to social information. Social communication deficits and hyperactive/impulsive traits are associated with impaired social perception abilities; these findings highlight overlapping cognitive and behavioral manifestations across disorders.

Using an objective structured video exam to identify differential understanding of aspects of communication skills

Background: Effective communication in health care is associated with patient satisfaction and improved clinical outcomes. Professional schools increasingly incorporate communication training into their curricula. The objective structured video exam (OSVE) is a video-based examination that provides an economical way of assessing students’ knowledge of communication skills. This study presents a scoring strategy that enables blueprinting of an OSVE to consensus guidelines, to determine which aspects of communication skills create the most difficulty for students to understand and to what degree understanding improves through experiential communication skills training. Methods: Five interactions between a healthcare professional and client were scripted and filmed using standardized patients. The dialogues were mapped onto the Kalamazoo consensus statement by having five communication experts view each video and identify effective and ineffective use of communication skills. Undergraduate students enrolled in a communications course completed an OSVE on three occasions. Results: A total of 79 students completed at least one testing session. The scores assigned supported the validity of the scoring strategy as an indication of knowledge growth. Considerable variability was observed across Kalamazoo sub-domains. Conclusion: With further refining, this scoring approach may prove useful for educators to tailor their education and assessment practices to specific consensus guidelines.

Genomic Disorders in Psychiatry—What Does the Clinician Need to Know?

Purpose of ReviewThe purpose of this review is to summarize the role of genomic disorders in various psychiatric conditions and to highlight important recent advances in the field that are of potential clinical relevance.Recent FindingsGenomic disorders are caused by large rare recurrent deletions and duplications at certain chromosomal “hotspots” (e.g., 22q11.2, 16p11.2, 15q11-q13, 1q21.1, 15q13.3) across the genome. Most overlap multiple genes, affect development, and are associated with variable cognitive and other neuropsychiatric expression. Although individually rare, genomic disorders collectively account for a significant minority of intellectual disability, autism spectrum disorder, and schizophrenia.SummaryGenome-wide chromosomal microarray analysis is capable of detecting all genomic disorders in a single test, offering the first opportunity for routine clinical genetic testing in psychiatric practice.

Oxytocin Receptor Polymorphisms are Differentially Associated with Social Abilities across Neurodevelopmental Disorders

Oxytocin is a pituitary neuropeptide that affects social behaviour. Single nucleotide polymorphisms (SNPs) in the oxytocin receptor gene (OXTR) have been shown to explain some variability in social abilities in control populations. Whether these variants similarly contribute to the severity of social deficits experienced by children with neurodevelopmental disorders is unclear. Social abilities were assessed in a group of children with autism spectrum disorder (ASD, n = 341) or attention deficit hyperactivity disorder (ADHD, n = 276) using two established social measures. Scores were compared by OXTR genotype (rs53576, rs237887, rs13316193, rs2254298). Unexpectedly, the two most frequently studied OXTR SNPs in the general population (rs53576 and rs2254298) were associated with an increased severity of social deficits in ASD (p < 0.0001 and p = 0.0005), yet fewer social deficits in ADHD (p = 0.007 and p < 0.0001). We conclude that these genetic modifier alleles are not inherently risk-conferring with respect to their impact on social abilities; molecular investigations are greatly needed.

Neuroimaging in Autism Spectrum Disorders

This chapter reviews the existing literature on neuroimaging in autism spectrum disorders. Research methodology and significant findings from structural and functional magnetic resonance imaging (MRI), magnetic resonance spectrometry (MRS) and positron emission tomography (PET) are described. Overall, despite significant heterogeneity in study results, a pattern emerges suggesting early brain overgrowth in the first few years of life, followed by dysmaturation in adolescence. Connectivity analyses reveal impaired long-range connectivity as well as increased local and/or subcortical connectivity in ASD. Such findings help to inform hypotheses regarding the etiopathogenesis of this condition, but have yet to yield practical clinical applications.

An advocacy experience for medical students.

Promoting advocacy and social responsibility is a requirement of medical education. This article describes a brief clinical educational initiative to foster advocacy amongst medical students, and explores student attitudes towards homelessness.