(C) 2011 IBRO. Published by Elsevier Ltd. All rights reserved.”
“Pathogen species with high mutation rates are likely to accumulate deleterious mutations that reduce their reproductive potential within the host. By altering the within-host growth rate of the pathogen, the deleterious mutation load has the potential to affect epidemiological properties such as prevalence, mean pathogen load, and the mean duration of infections: Here, I examine an epidemiological model that allows for multiple segregating mutations that affect within-host replication efficiency. The model

demonstrates a complex range of outcomes depending on pathogen mutation selleck compound rate, including two distinct, widely separated mutation rates associated with high pathogen prevalence. The CHIR-99021 clinical trial low mutation rate prevalence peak is associated with small amounts of genetic diversity

within the pathogen population, relatively stable prevalence and infection dynamics, and genetic variation partitioned between hosts. The high mutation rate peak is characterized by considerable genetic diversity both within and between hosts, relatively frequent invasions by more virulent types, and is qualitatively similar to an RNA virus quasispecies. The two prevalence peaks are separated by a valley where natural selection favors evolution toward the optimal within-host state, which is associated with high virulence and relatively rapid host mortality. Both chronic and acute infections are examined using stochastic forward simulations. (C) 2011 Elsevier Ltd. All

rights reserved.”
“Recent evidence indicates that individuals with Williams syndrome (WS), a rare genetically based neurodevelopmental disorder, show abnormalities of parietal and cerebellar Molecular motor regions of the brain that may be involved in the visual control of locomotion. Here we examined whether parietal and cerebellar abnormalities contribute to deficits in spatiotemporal characteristics and foot placement variability during obstacle crossing in adults with WS, when compared with an IQ-matched group of adults with Down syndrome (DS) and typically developing adult controls. We used the GAITRite walkway to examine the spatiotemporal characteristics and foot placement variability relative to a small ground-based obstacle in the travel path. We found that adults with WS showed late adjustments to spatiotemporal gait characteristics alongside an exaggerated and more spatially constrained visual guidance of foot positioning in the final steps prior to stepping over the obstacle. In contrast, the adults with DS showed longer step duration and more variable step length and step duration during the crossing and recovery steps after the obstacle, suggestive of cerebellar dysfunction.