Tallinn University of Technology

About: Tallinn University of Technology is a education organization based out in Tallinn, Estonia. It is known for research contribution in the topics: European union & Computer science. The organization has 3688 authors who have published 10313 publications receiving 145058 citations. The organization is also known as: Tallinn Technical University & Tallinna Tehnikaülikool.

The CB 1 cannabinoid receptor signals striatal neuroprotection via a PI3K/Akt/mTORC1/BDNF pathway

Abstract: The CB1 cannabinoid receptor, the main molecular target of endocannabinoids and cannabis active components, is the most abundant G protein-coupled receptor in the mammalian brain. In particular, the CB1 receptor is highly expressed in the basal ganglia, mostly on terminals of medium-sized spiny neurons, where it plays a key neuromodulatory function. The CB1 receptor also confers neuroprotection in various experimental models of striatal damage. However, the assessment of the physiological relevance and therapeutic potential of the CB1 receptor in basal ganglia-related diseases is hampered, at least in part, by the lack of knowledge of the precise mechanism of CB1 receptor neuroprotective activity. Here, by using an array of pharmacological, genetic and pharmacogenetic (designer receptor exclusively activated by designer drug) approaches, we show that (1) CB1 receptor engagement protects striatal cells from excitotoxic death via the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin complex 1 pathway, which, in turn, (2) induces brain-derived neurotrophic factor (BDNF) expression through the selective activation of BDNF gene promoter IV, an effect that is mediated by multiple transcription factors. To assess the possible functional impact of the CB1/BDNF axis in a neurodegenerative-disease context in vivo, we conducted experiments in the R6/2 mouse, a well-established model of Huntington's disease, in which the CB1 receptor and BDNF are known to be severely downregulated in the dorsolateral striatum. Adeno-associated viral vector-enforced re-expression of the CB1 receptor in the dorsolateral striatum of R6/2 mice allowed the re-expression of BDNF and the concerted rescue of the neuropathological deficits in these animals. Collectively, these findings unravel a molecular link between CB1 receptor activation and BDNF expression, and support the relevance of the CB1/BDNF axis in promoting striatal neuron survival.

Twenty-five-year trends in myocardial infarction attack and mortality rates, and case-fatality, in six European populations

Abstract: Objective Due to the burden of coronary heart disease (CHD), the monitoring of CHD trends is required. This study sought to examine the acute myocardial infarction (AMI) trends in attack and mortality rates, and in 28-day case-fatality, in six European populations during 1985–2010. Methods Data consisted of 78 128 AMI events included in eight population-based registries from Finland (several populations), Italy (Brianza and Varese), Germany (Augsburg), France (Haute-Garonne), Spain (Girona) and Estonia (Tallinn). AMI event rates and case-fatality trends were analysed using the annual percentage change (APC) obtained by negative binomial and joinpoint regression. Results AMI attack and mortality rates decreased in most populations. Finland experienced the steepest decline in attack rates (APC=−4.4% (95% CI −5.1 to −2.9) in men; −4.0% (−5.1 to −2.8), in women). Total-hospital and inhospital case-fatality decreased in all populations except in Tallinn. The steepest decline in total case-fatality occurred in Spain (−3.8% (−5.3 to −2.4) in men; −5.1% (−6.9 to −3.3) in women). Prehospital case-fatality trends differed significantly by population and sex. The trends for all included populations showed a significant decline in AMI event rates and case-fatality, in both sexes and all age groups. However, in women aged 65–74 years, a significant increase in total case-fatality occurred in 2005–2010 (4.7% (0.7 to 8.8)). Conclusions AMI event rates and inhospital case-fatality declined in 1985–2010 in almost all populations analysed. Prehospital case-fatality declined only in certain population groups, showing differences by sex. These results highlight the need of specific strategies in AMI prevention for certain groups and populations.

Evidence for scale- and disturbance-dependent trait assembly patterns in dry semi-natural grasslands

Abstract: 1. The mechanisms driving nonrandom assembly patterns in plant communities have long been of interest in ecological research. Competing ecological theories predict that coexisting species may either be more functionally dissimilar than expected by chance (with functional divergence' mainly reflecting niche differentiation) or be functionally more similar than expected (with functional convergence' reflecting either the outcome of environmental filtering or weaker-competitor exclusion effects). Assembly patterns are usually assessed at a single scale and disturbance regime, whereas considering different spatial scales and disturbance regimes may clarify the underlying assembly mechanisms. 2. We tested the prediction that convergence and divergence are scale- and disturbance- dependent in grazed and abandoned species-rich dry grasslands within a 22km(2) landscape in south-eastern Sweden. Convergence and divergence were tested for plant species' traits and phylogenetic relationships at three nested spatial scales: within 412 plots (50x50cm, divided into 10x10cm subplots), within 117 grassland patches (from 0.02 to 11.63ha) and within the whole landscape (across patches). 3. At the finest scale (10x10cm subplots within plots), coexisting species were more different than expected by chance (divergence), both functionally and phylogenetically, suggesting niche differentiation. At the intermediate scale (50x50cm plots within patches), coexisting species showed convergence, suggesting environmental filtering. No significant deviations from random expectations were detected at the broadest scale (patches within the 22km(2) landscape) - suggesting the prevalence of dispersal limitation at this scale. The fact that nonrandom patterns were particularly evident under grazed conditions is consistent with the prediction that assembly patterns are disturbance dependent. 4. Synthesis. This study shows that multiple trait-based assembly processes operate simultaneously in species-rich communities, across spatial scales and disturbance regimes. The results support earlier theoretical predictions that divergence between coexisting species may be an important driver of community assembly, particularly at finer spatial scales, where species compete for the same local resources. In contrast, environmental filtering is expected at broader spatial scales, where species growing in particular environmental conditions share traits that are adaptive under those conditions. Within given habitat types, dispersal limitation may, however, override environmental filtering at increasing spatial scales of observation. (Less)