Aging of the mammalian gastrointestinal tract: a complex organ system

Gastrointestinal disorders are a major cause of morbidity in the elderly population. The gastrointestinal tract is the most complex organ system; its diverse cells perform a range of functions essential to life, not only secretion, digestion, absorption and excretion, but also, very importantly, defence. The gastrointestinal tract acts not only as a barrier to harmful materials and pathogens but also contains the vast number of beneficial bacterial populations that make up the microbiota. Communication between the cells of the gastrointestinal tract and the central nervous and endocrine systems modifies behaviour; the organisms of the microbiota also contribute to this brain–gut–enteric microbiota axis. Age-related physiological changes in the gut are not only common, but also variable, and likely to be influenced by external factors as well as intrinsic aging of the cells involved. The cellular and molecular changes exhibited by the aging gut cells also vary. Aging intestinal smooth muscle cells exhibit a number of changes in the signalling pathways that regulate contraction. There is some evidence for age-associated degeneration of neurons and glia of the enteric nervous system, although enteric neuronal losses are likely not to be nearly as extensive as previously believed. Aging enteric neurons have been shown to exhibit a senescence-associated phenotype. Epithelial stem cells exhibit increased mitochondrial mutation in aging that affects their progeny in the mucosal epithelium. Changes to the microbiota and intestinal immune system during aging are likely to contribute to wider aging of the organism and are increasingly important areas of analysis. How changes of the different cell types of the gut during aging affect the numerous cellular interactions that are essential for normal gut functions will be important areas for future aging research

Concordance of multiple informant assessment of school-based social skills intervention and association with child outcomes: Results from a randomized trial

Background Fidelity, or the degree to which an intervention is implemented as designed, is essential for effective implementation. There has been a growing emphasis on assessing fidelity of evidence-based practices for autistic children in schools. Fidelity measurement should be multidimensional and focus on core intervention components and assess their link with program outcomes. This study evaluated the relation between intervention fidelity ratings from multiple sources, tested the relation between fidelity ratings and child outcomes, and determined the relations between core intervention components and child outcomes in a study of an evidence-based psychosocial intervention designed to promote inclusion of autistic children at school, Remaking Recess. Method This study extends from a larger randomized controlled trial examining the effect of implementation support on Remaking Recess fidelity and child outcomes. Schools were randomized to receive the intervention or the intervention plus implementation support. Observers, intervention coaches, and school personnel completed fidelity measures to rate completion and quality of intervention delivery. A measure of peer engagement served as the child outcome. Pearson correlation coefficients were calculated to determine concordance between raters. Two sets of hierarchical linear models were conducted using fidelity indices as predictors of peer engagement. Results Coach- and self-rated completion and quality scores, observer- and self-rated quality scores, and observer- and coach-rated quality fidelity scores were significantly correlated. Higher observer-rated completion and quality fidelity scores were predictors of higher peer engagement scores. No single intervention component emerged as a significant predictor of peer engagement. Conclusions This study demonstrates the importance of using a multidimensional approach for measuring fidelity, testing the link between fidelity and child outcomes, and examining how core intervention components may be associated with child outcomes. Future research should clarify how to improve multi-informant reports to provide “good enough” ratings of fidelity that provide meaningful information about outcomes in community settings