Variations in the APOE allele or BDNF Val66Met polymorphism are not associated with changes in cognitive function following a tertiary education intervention in older adults: the Tasmanian Healthy Brain Project.

The apolipoprotein (APOE) ε4 allele and the Met variant of the brain-derived neurotrophic factor (BDNF) Val66Met polymorphism are associated with reduced cognitive function in older adults. The aim of this study was to examine the independent and interactional effect of the APOE ε4 allele and BDNF Val66Met polymorphism on cognitive function in a cohort of healthy older adults who had undertaken further university level education. Multiple group latent growth curve modeling revealed no change in cognitive function over time in APOE ε4-carriers or in BDNF Met-carriers, nor in carriers of both APOE-ε4 and BDNF-Met alleles. Further, the results indicate that allelic variation in either APOE or BDNF does not modify the beneficial effects of a university-based education intervention on cognitive function over a 4-year period following the intervention

Sending Your Grandparents to University Increases Cognitive Reserve: The Tasmanian Healthy Brain Project.

Increasing an individual’s level of cognitive reserve (CR) has been suggested as a nonpharmacological approach to reducing the risk for Alzheimer’s disease. We examined changes in CR in older adults participating over 4 years in the Tasmanian Healthy Brain Project. Method: A sample of 459 healthy older adults between 50 and 79 years of age underwent a comprehensive annual assessment of current CR, neuropsychological function, and psychosocial factors over a 4-year period. The intervention group of 359 older adults (M � 59.61 years, SD � 6.67) having completed a minimum of 12 months part-time university study were compared against a control reference group of 100 adults (M � 62.49 years, SD � 6.24) who did not engage in further education. Results: Growth mixture modeling demonstrated that 44.3% of the control sample showed no change in CR, whereas 92.5% of the further education participants displayed a significant linear increase in CR over the 4 years of the study. These results indicate that older adults engaging in high-level mental stimulation display an increase in CR over a 4-year period. Conclusion: Increasing mental activity in older adulthood may be a viable strategy to improve cognitive function and offset cognitive decline associated with normal aging

Self-Assembly of 4-sided Fractals in the Two-handed Tile Assembly Model

We consider the self-assembly of fractals in one of the most well-studied models of tile based self-assembling systems known as the Two-handed Tile Assembly Model (2HAM). In particular, we focus our attention on a class of fractals called discrete self-similar fractals (a class of fractals that includes the discrete Sierpi\'nski carpet). We present a 2HAM system that finitely self-assembles the discrete Sierpi\'nski carpet with scale factor 1. Moreover, the 2HAM system that we give lends itself to being generalized and we describe how this system can be modified to obtain a 2HAM system that finitely self-assembles one of any fractal from an infinite set of fractals which we call 4-sided fractals. The 2HAM systems we give in this paper are the first examples of systems that finitely self-assemble discrete self-similar fractals at scale factor 1 in a purely growth model of self-assembly. Finally, we show that there exists a 3-sided fractal (which is not a tree fractal) that cannot be finitely self-assembled by any 2HAM system

Knots and Particles

Using methods of high performance computing, we have found indications that knotlike structures appear as stable finite energy solitons in a realistic 3+1 dimensional model. We have explicitly simulated the unknot and trefoil configurations, and our results suggest that all torus knots appear as solitons. Our observations open new theoretical possibilities in scenarios where stringlike structures appear, including physics of fundamental interactions and early universe cosmology. In nematic liquid crystals and 3He superfluids such knotted solitons might actually be observed.Comment: 9 pages, 4 color eps figures and one b/w because of size limit (color version available from authors

Human helminth therapy to treat inflammatory disorders - where do we stand?

Parasitic helminths have evolved together with the mammalian immune system over many millennia and as such they have become remarkably efficient modulators in order to promote their own survival. Their ability to alter and/or suppress immune responses could be beneficial to the host by helping control excessive inflammatory responses and animal models and pre-clinical trials have all suggested a beneficial effect of helminth infections on inflammatory bowel conditions, MS, asthma and atopy. Thus, helminth therapy has been suggested as a possible treatment method for autoimmune and other inflammatory disorders in humans

Environmental novelty exacerbates stress hormones and Aβ pathology in an Alzheimer’s model

Cognitive stimulation has been proposed as a non-pharmacological intervention to be used in primary, secondary and tertiary prevention approaches for Alzheimer’s disease. A common familial Alzheimer’s disease transgenic model showed heightened levels of the stress hormone, corticosterone. When exposed to periodic enhanced cognitive stimulation, these animals demonstrated further heightened levels of corticosterone as well as increased Aβ pathology. Hence, Alzheimer’s disease may be associated with hypothalamic-pituitary-adrenal (HPA) axis dysfunction, causing stimulatory environments to become stress-inducing, leading to a glucocorticoid-pathology cycle contributing to further Aβ release and plaque formation. This finding suggests that stimulation-based interventions and local environments for people with Alzheimer’s disease need to be designed to minimise a stress response that may exacerbate brain pathology

Association between the serotonin transporter gene polymorphism and verbal learning in older adults is moderated by gender

The S allele of the functional 5-HTTLPR polymorphism has previously been associated with reductions in memory function. Giventhe change in function of the serotonergic system in older adults, and the functional consequences of memory decline in this agegroup, further investigation into the impact of 5-HTTLPR in healthy older adults is required. This investigation examined the effectof 5-HTTLPR variants (S carriers versus L/L homozygotes) on verbal and visual episodic memory in 438 healthy older adultsparticipating in the Tasmanian Healthy Brain Project (age range 50–79 years, M= 60.35, s.d. = 6.75). Direct effects of HTTLPR onmemory processes, in addition to indirect effects through interaction with age and gender, were assessed. Although no directeffects of 5-HTTLPR on memory processes were identified, our results indicated that gender significantly moderated the impact that5-HTTLPR variants exerted on the relationship between age and verbal episodic memory function as assessed by the Rey AuditoryVerbal Learning Test. No significant direct or indirect effects were identified in relation to visual memory performance. Overall, thisinvestigation found evidence to suggest that 5-HTTLPR genotype affects the association of age and verbal episodic memory formales and females differently, with the predicted negative effect of S carriage present in males but not females. Such findingsindicate a gender-dependent role for 5-HTTLPR in the verbal episodic memory system of healthy older adults

Patent Human Infections with the Whipworm, Trichuris trichiura, Are Not Associated with Alterations in the Faecal Microbiota

Background: The soil-transmitted helminth (STH), Trichuris trichiura colonises the human large intestine where it may modify inflammatory responses, an effect possibly mediated through alterations in the intestinal microbiota. We hypothesised that patent T. trichiura infections would be associated with altered faecal microbiota and that anthelmintic treatment would induce a microbiota resembling more closely that observed in uninfected individuals. Materials and Methods: School children in Ecuador were screened for STH infections and allocated to 3 groups: uninfected, T. trichiura only, and mixed infections with T. trichiura and Ascaris lumbricoides. A sample of uninfected children and those with T. trichiura infections only were given anthelmintic treatment. Bacterial community profiles in faecal samples were studied by 454 pyrosequencing of 16 S rRNA genes. Results: Microbiota analyses of faeces were done for 97 children: 30 were uninfected, 17 were infected with T. trichiura, and 50 with T. trichiura and A. lumbricoides. Post-treatment samples were analyzed for 14 children initially infected with T. trichiura alone and for 21 uninfected children. Treatment resulted in 100% cure of STH infections. Comparisons of the microbiota at different taxonomic levels showed no statistically significant differences in composition between uninfected children and those with T. trichiura infections. We observed a decreased proportional abundance of a few bacterial genera from the Clostridia class of Firmicutes and a reduced bacterial diversity among children with mixed infections compared to the other two groups, indicating a possible specific effect of A. lumbricoides infection. Anthelmintic treatment of children with T. trichiura did not alter faecal microbiota composition. Discussion: Our data indicate that patent human infections with T. trichiura may have no effect on faecal microbiota but that A. lumbricoides colonisation might be associated with a disturbed microbiota. Our results also catalogue the microbiota of rural Ecuadorians and indicate differences with individuals from more urban industrialised societies