Prevalence and Burden of Gait Disorders in Elderly Men and Women Aged 60–97 Years: A Population-Based Study

Background

Although gait disorders are common in the elderly, the prevalence and overall burden of these disorders in the general community is not well defined.

Methods

In a cross-sectional investigation of the population-based Bruneck Study cohort, 488 community-residing elderly aged 60–97 years underwent a thorough neurological assessment including a standardized gait evaluation. Gait disorders were classified according to an accepted scheme and their associations to falls, neuropsychological measures, and quality of life were explored.

Results

Overall, 32.2% (95% confidence interval [CI] 28.2%–36.4%) of participants presented with impaired gait. Prevalence increased with age (p<0.001), but 38.3% (95%CI 30.1%–47.3%) of the subjects aged 80 years or older still had a normally preserved gait. A total of 24.0% (95%CI 20.4%–28.0%) manifested neurological gait disorders, 17.4% (14.3%–21.0%) non-neurological gait problems, and 9.2% (6.9%–12.1%) a combination of both. While there was no association of neurological gait disorders with gender, non-neurological gait disorders were more frequent in women (p = 0.012). Within the group of neurological gait disorders 69.2% (95%CI 60.3%–76.9%) had a single distinct entity and 30.8% (23.1%–39.7%) had multiple neurological causes for gait impairment. Gait disorders had a significant negative impact on quantitative gait measures, but only neurological gait disorders were associated with recurrent falls (odds ratio 3.3; 95%CI 1.4–7.5; p = 0.005 for single and 7.1; 2.7–18.7; p<0.001 for multiple neurological gait disorders). Finally, we detected a significant association of gait disorders, in particular neurological gait disorders, with depressed mood, cognitive dysfunction, and compromised quality of life.

Conclusions

Gait disorders are common in the general elderly population and are associated with reduced mobility. Neurological gait disorders in particular are associated with recurrent falls, lower cognitive function, depressed mood, and diminished quality of life.     

Evolution of fitnesses and allele frequencies in a population with spatially heterogeneous selection pressures

The level of gene flow considerably influences the outcome of evolutionary processes in structured populations with spatial heterogeneity in selection pressures; low levels of gene flow may allow local adaptation whereas high levels of gene flow may oppose this process thus preventing the stable maintenance of polymorphism. Indeed, proportions of fitness space that successfully maintain polymorphism are substantially larger in spatially heterogenous populations with lower to moderate levels of gene flow when compared to single-deme models. Nevertheless, the effect of spatial heterogeneity on the evolutionary construction of polymorphism is less clear. We have investigated the levels of polymorphism resulting from a simple two-deme construction model, which incorporates recurrent mutation as well as selection. We further compared fitness properties, stability of equilibria, and frequency distribution patterns emerging from the construction approach and compared these to the static fitness-space approach. The construction model either promotes or constrains the level of polymorphisms, depending on the levels of gene flow. Comparison of the fitness properties resulting from both approaches shows that they maintain variation in different parts of fitness space. The part of fitness space resulting from construction is more stable than that implied by the ahistoric fitness-space approach. Finally, the equilibrium allele-frequency distribution patterns vary substantially with different levels of gene flow, underlining the importance of correctly sampling spatial structure if these patterns are to be used to estimate population-genetic processes.     

Influence of the public's perception,attitudes, and knowledge on the implementation of integrated pest management for household insect pests

Households are mini‐ecosystems that provide a variety of conditions in which a variety of insect species can develop. Whether these insects are considered pests, largely depends on the perception, attitudes, and knowledge of the human inhabitants of the house. If considered unacceptable, residents can attempt to manage the insects themselves, or hire a professional. A pest management professional can provide a quick‐fix solution, often relying on the sole use of insecticides, or a sustainable solution through integrated pest management (IPM). In this review, it is discussed how the public's perception, attitudes, and knowledge affect the implementation of IPM in the household through the following steps: inspection, identification, establishment of a threshold level, pest control, and evaluation of effectiveness. Furthermore, recent and novel developments within the fields of inspection, identification, and pest control that allow to address pest infestations more effectively are described and their implementation in the household environment is discussed. In general, pest management in the household environment is reactive instead of pro‐active. The general public lacks the knowledge of the pest insects’ biology to identify the species, perform a proper inspection and identify causes of pest presence, as well as the knowledge of the available tools for monitoring and pest control. The percentage of individuals that seek professional aid in identification and pest control is relatively low. Moreover, the perception of and attitudes towards household insects generally result in low threshold levels. Current developments of methods for monitoring, identification, and control of insect pests in the household environment are promising, such as DNA barcoding, matrix‐assisted laser desorption/ionization time‐of‐flight and RNA interference. Efforts should be strengthened to alter the perception and attitude, and increase the knowledge of the non‐professional stakeholders, so that correct pest management decisions can be taken.     

Alk3 mediated Bmp signaling controls the contribution of epicardially derived cells to the tissues of the atrioventricular junction

Recent studies using mouse models for cell fate tracing of epicardial derived cells (EPDCs) have demonstrated that at the atrioventricular (AV) junction EPDCs contribute to the mesenchyme of the AV sulcus, the annulus fibrosus, and the parietal leaflets of the AV valves. There is little insight, however, into the mechanisms that govern the contribution of EPDCs to these tissues. While it has been demonstrated that bone morphogenetic protein (Bmp) signaling is required for AV cushion formation, its role in regulating EPDC contribution to the AV junction remains unexplored. To determine the role of Bmp signaling in the contribution of EPDCs to the AV junction, the Bmp receptor activin-like kinase 3 (Alk3; or Bmpr1a) was conditionally deleted in the epicardium and EPDCs using the mWt1/IRES/GFP-Cre (Wt1^Cre) mouse. Embryonic Wt1^Cre;Alk3^fl/fl specimens showed a significantly smaller AV sulcus and a severely underdeveloped annulus fibrosus. Electrophysiological analysis of adult Wt1^Cre;Alk3^fl/fl mice showed, unexpectedly, no ventricular pre-excitation. Cell fate tracing revealed a significant decrease in the number of EPDCs within the parietal leaflets of the AV valves. Postnatal Wt1^Cre;Alk3^fl/fl specimens showed myxomatous changes in the leaflets of the mitral valve. Together these observations indicate that Alk3 mediated Bmp signaling is important in the cascade of events that regulate the contribution of EPDCs to the AV sulcus, annulus fibrosus, and the parietal leaflets of the AV valves. Furthermore, this study shows that EPDCs do not only play a critical role in early developmental events at the AV junction, but that they also are important in the normal maturation of the AV valves.     

Arabidopsis tubulin folding cofactor B interacts with alpha-tubulin in vivo

Microtubule biogenesis requires alphabeta tubulin dimers that are generated from alpha and beta tubulin following post-translational modification by several tubulin folding cofactors (TFCs). Here we report the isolation and characterization of Arabidopsis TFCB (AtTFCB). AtTFCB is expressed in all organs of Arabidopsis. The subcellular localization of AtTFCB is mainly cytosolic. AtTFCB-overexpressing cells have fewer microtubules compared with the controls. Multimode fluorescence resonance energy transfer (FRET) microscopy reveals a direct physical interaction of AtTFCB with alpha tubulin in living plant cells. We conclude that AtTFCB interacts with alpha tubulin in vivo and its overexpression reduces the number of microtubules.     

Substantial linkage disequilibrium across the insulin-degrading enzyme locus but no association with late-onset Alzheimer's disease

Insulin-degrading enzyme (IDE; insulysin; EC 3.4.24.56) is a 110-kDa neutral metallopeptidase that can degrade a number of peptides including beta-amyloid. The gene encoding IDE is located on chromosome 10 close to a region of linkage for late-onset Alzheimer's disease (LOAD) and thus is a functional and positional candidate for this disorder. We analysed all of the coding exons, untranslated regions and 1000 bp of 5'-flanking sequence of IDE by using denaturing high-performance liquid chromatography and sequencing. We detected eight single nucleotide polymorphisms (SNPs), three in the 5' flanking sequence and five in the coding sequence, of which three were found at lower than 5% frequency. None of them changed the amino acid sequence. We genotyped the five SNPs with allele frequencies of more than 5% in 133 Caucasian LOAD cases and 135 controls collected in the UK and 95 cases and 117 controls collected at the Mayo Clinic, Rochester, USA. Two of the SNPs were analysed in a further independent case-control sample (Washington University, St. Louis: 86 cases, 94 controls). No significant association was found with any individual SNP in any of the samples or with any haplotypes. Analysis of the marker D10S583, which maps 36 kb upstream of IDE, also failed to show association in 134 cases and 111 matched controls from the UK ( P=0.63). Strong linkage disequilibrium was detected between the five SNPs that spanned the whole of the 120-kb genomic region of IDE and one major and a number of minor haplotypes were detected in the populations studied. We conclude that IDE does not make a substantial contribution to the aetiology of LOAD and therefore cannot account for the linkage between LOAD and 10q.     

Cognitive profile of students who enter higher education with an indication of dyslexia

For languages other than English there is a lack of empirical evidence about the cognitive profile of students entering higher education with a diagnosis of dyslexia. To obtain such evidence, we compared a group of 100 Dutch-speaking students diagnosed with dyslexia with a control group of 100 students without learning disabilities. Our study showed selective deficits in reading and writing (effect sizes for accuracy between d = 1 and d = 2), arithmetic (d≈1), and phonological processing (d>0.7). Except for spelling, these deficits were larger for speed related measures than for accuracy related measures. Students with dyslexia also performed slightly inferior on the KAIT tests of crystallized intelligence, due to the retrieval of verbal information from long-term memory. No significant differences were observed in the KAIT tests of fluid intelligence. The profile we obtained agrees with a recent meta-analysis of English findings suggesting that it generalizes to all alphabetic languages. Implications for special arrangements for students with dyslexia in higher education are outlined.     

Temperature,resources and predation interact to shape phytoplankton size–abundance relationships at a continental scale

Aim

Communities contain more individuals of small species and fewer individuals of large species. According to the ‘metabolic theory of ecology’, the relationship of log mean abundance with log mean body size across communities should exhibit a slope of −3/4 that is invariant across environmental conditions. Here, we investigate whether this slope is indeed invariant or changes systematically across gradients in temperature, resource availability and predation pressure.

Location

1048 lakes across the USA.

Time Period

2012.

Major Taxa Studied

Phytoplankton.

Results

We found that the size–abundance relationship across all sampled phytoplankton communities was significantly lower than −3/4 and near −1 overall. More importantly, we found strong evidence that the environment affects the slope: it varies between −0.33 and −0.93 across interacting gradients of temperature, resource (phosphorus) supply and zooplankton predation pressure. Therefore, phytoplankton communities have orders of magnitude more small or large cells depending on environmental conditions across geographical locations.

Conclusion

Our results emphasise the importance of the environmental factors' effect on macroecological patterns that arise through physiological and ecological processes. An investigation of the mechanisms underlying the link between individual energetics constrain and macroecological patterns would allow to predict how global warming and changes in nutrients will alter large-scale ecological patterns in the future.