Evaluating the Effect of Stressors on Thiaminase Activity in Alewife

Abstract.-No consistent explanation has been found for the variability in the thiaminase activity of alewives Alosa pseudoharengus despite the role of alewife thiaminase in large-scale salmonine mortality in the Laurentian Great Lakes. We conducted experiments to evaluate the effect of two stressors, reduced salt content in the water and food limitation, on alewife thiaminase activity. Alewives were subjected to treatments in replicated tanks in which conductivity was lowered (,100 lS/cm) for 8 d and feeding was limited for 39 d. Circulating white blood cells, plasma cortisol, plasma glucose, and whole-body thiaminase were measured in individual alewives to assess their response to these experimental treatments. Alewives from the controls had significantly larger numbers of circulating white blood cells than those in the salt-reduced and food-limite

Consequences of “natural” disasters on aquatic life and habitats

“Natural” disasters (also known as geophysical disasters) involve physical processes that have a direct or indirect impact on humans. These events occur rapidly and may have severe consequences for resident flora and fauna as their habitat undergoes dramatic and sudden change. Although most studies have focused on the impact of natural disasters on humans and terrestrial systems, geophysical disasters can also impact aquatic ecosystems. Here, we provide a synthesis on the effects of the most common and destructive geophysical disasters on aquatic systems (life and habitat). Our approach spanned realms (i.e., freshwater, estuarine, and marine) and taxa (i.e., plants, vertebrates, invertebrates, and microbes) and included floods, droughts, wildfires, hurricanes/cyclones/typhoons, tornadoes, dust storms, ice storms, avalanches (snow), landslides, volcanic eruptions, earthquakes (including limnic eruptions), tsunamis, and cosmic events. Many geophysical disasters have dramatic effects on aquatic systems. The evidence base is somewhat limited for some natural disasters because transient events (e.g., tornadoes and floods) are difficult to study. Most natural disaster studies focus on geology/geomorphology and hazard assessment for humans and infrastructure. However, the destruction of aquatic systems can impact humans indirectly through loss of food security, cultural services, or livelihoods. Many geophysical disasters interact in complex ways (e.g., wildfires often lead to landslides and flooding) and can be magnified or otherwise mediated by human activities. Our synthesis reveals that geophysical events influence aquatic ecosystems, often in negative ways, yet systems can be resilient provided that effects are not compounded by anthropogenic stressors. It is difficult to predict or prevent geophysical disasters but understanding how aquatic ecosystems are influenced by geophysical events is important given the inherent connection between peoples and aquatic ecosystems.acceptedVersio

Efficacy of Fumaric Acid Esters in the R6/2 and YAC128 Models of Huntington's Disease

Huntington's disease (HD) is an autosomal dominantly inherited progressive neurodegenerative disease. The exact sequel of events finally resulting in neurodegeneration is only partially understood and there is no established protective treatment so far. Some lines of evidence speak for the contribution of oxidative stress to neuronal tissue damage. The fumaric acid ester dimethylfumarate (DMF) is a new disease modifying therapy currently in phase III studies for relapsing-remitting multiple sclerosis. DMF potentially exerts neuroprotective effects via induction of the transcription factor “nuclear factor E2-related factor 2” (Nrf2) and detoxification pathways. Thus, we investigated here the therapeutic efficacy of DMF in R6/2 and YAC128 HD transgenic mice which mimic many aspects of HD and are characterized by an enhanced generation of free radicals in neurons. Treatment with DMF significantly prevented weight loss in R6/2 mice between postnatal days 80–90. At the same time, DMF treatment led to an attenuated motor impairment as measured by the clasping score. Average survival in the DMF group was 100.5 days vs. 94.0 days in the placebo group. In the histological analysis on day 80, DMF treatment resulted in a significant preservation of morphologically intact neurons in the striatum as well as in the motor cortex. DMF treatment resulted in an increased Nrf2 immunoreactivity in neuronal subpopulations, but not in astrocytes. These beneficial effects were corroborated in YAC128 mice which, after one year of DMF treatment, also displayed reduced dyskinesia as well as a preservation of neurons. In conclusion, DMF may exert beneficial effects in mouse models of HD. Given its excellent side effect profile, further studies with DMF as new therapeutic approach in HD and other neurodegenerative diseases are warranted

Comparative effectiveness and safety of non-vitamin K antagonists for atrial fibrillation in clinical practice: GLORIA-AF Registry

Background and purpose: Prospectively collected data comparing the safety and effectiveness of individual non-vitamin K antagonists (NOACs) are lacking. Our objective was to directly compare the effectiveness and safety of NOACs in patients with newly diagnosed atrial fibrillation (AF). Methods: In GLORIA-AF, a large, prospective, global registry program, consecutive patients with newly diagnosed AF were followed for 3 years. The comparative analyses for (1) dabigatran vs rivaroxaban or apixaban and (2) rivaroxaban vs apixaban were performed on propensity score (PS)-matched patient sets. Proportional hazards regression was used to estimate hazard ratios (HRs) for outcomes of interest. Results: The GLORIA-AF Phase III registry enrolled 21,300 patients between January 2014 and December 2016. Of these, 3839 were prescribed dabigatran, 4015 rivaroxaban and 4505 apixaban, with median ages of 71.0, 71.0, and 73.0 years, respectively. In the PS-matched set, the adjusted HRs and 95% confidence intervals (CIs) for dabigatran vs rivaroxaban were, for stroke: 1.27 (0.79–2.03), major bleeding 0.59 (0.40–0.88), myocardial infarction 0.68 (0.40–1.16), and all-cause death 0.86 (0.67–1.10). For the comparison of dabigatran vs apixaban, in the PS-matched set, the adjusted HRs were, for stroke 1.16 (0.76–1.78), myocardial infarction 0.84 (0.48–1.46), major bleeding 0.98 (0.63–1.52) and all-cause death 1.01 (0.79–1.29). For the comparison of rivaroxaban vs apixaban, in the PS-matched set, the adjusted HRs were, for stroke 0.78 (0.52–1.19), myocardial infarction 0.96 (0.63–1.45), major bleeding 1.54 (1.14–2.08), and all-cause death 0.97 (0.80–1.19). Conclusions: Patients treated with dabigatran had a 41% lower risk of major bleeding compared with rivaroxaban, but similar risks of stroke, MI, and death. Relative to apixaban, patients treated with dabigatran had similar risks of stroke, major bleeding, MI, and death. Rivaroxaban relative to apixaban had increased risk for major bleeding, but similar risks for stroke, MI, and death. Registration: URL: https://www.clinicaltrials.gov. Unique identifiers: NCT01468701, NCT01671007. Date of registration: September 2013

Anticoagulant selection in relation to the SAMe-TT2R2 score in patients with atrial fibrillation. the GLORIA-AF registry

Aim: The SAMe-TT2R2 score helps identify patients with atrial fibrillation (AF) likely to have poor anticoagulation control during anticoagulation with vitamin K antagonists (VKA) and those with scores >2 might be better managed with a target-specific oral anticoagulant (NOAC). We hypothesized that in clinical practice, VKAs may be prescribed less frequently to patients with AF and SAMe-TT2R2 scores >2 than to patients with lower scores. Methods and results: We analyzed the Phase III dataset of the Global Registry on Long-Term Oral Antithrombotic Treatment in Patients with Atrial Fibrillation (GLORIA-AF), a large, global, prospective global registry of patients with newly diagnosed AF and ≥1 stroke risk factor. We compared baseline clinical characteristics and antithrombotic prescriptions to determine the probability of the VKA prescription among anticoagulated patients with the baseline SAMe-TT2R2 score >2 and ≤ 2. Among 17,465 anticoagulated patients with AF, 4,828 (27.6%) patients were prescribed VKA and 12,637 (72.4%) patients an NOAC: 11,884 (68.0%) patients had SAMe-TT2R2 scores 0-2 and 5,581 (32.0%) patients had scores >2. The proportion of patients prescribed VKA was 28.0% among patients with SAMe-TT2R2 scores >2 and 27.5% in those with scores ≤2. Conclusions: The lack of a clear association between the SAMe-TT2R2 score and anticoagulant selection may be attributed to the relative efficacy and safety profiles between NOACs and VKAs as well as to the absence of trial evidence that an SAMe-TT2R2-guided strategy for the selection of the type of anticoagulation in NVAF patients has an impact on clinical outcomes of efficacy and safety. The latter hypothesis is currently being tested in a randomized controlled trial. Clinical trial registration: URL: https://www.clinicaltrials.gov//Unique identifier: NCT01937377, NCT01468701, and NCT01671007

Identifying the Spatial Pattern of Wood Distribution in Northeastern North American Streams." Geomorphology 135

The spatial distribution of instream wood influences important ecological processes but has proven challenging to describe quantitatively. We present a modified version of a previously described metric used to quantify the spatial extent and pattern of instream wood distribution, then apply this approach in evaluating the distribution of wood habitat in forested northeastern North American streams. This revised metric, a 'binned neighbor-K analysis', provides greater resolution in evaluating the presence of aggregated, periodic, or segregated wood distributions in stream ecosystems. We employed this metric in evaluating the distribution of wood within 17 streams in two regions of northeastern North America. Our results indicate that the binned neighbor-K approach more accurately represents the spatial extent at which wood accumulates in streams by identifying recurring intervals in streams within which instream wood is not present and by more accurately quantifying the spatial extent of wood aggregations and periodically repeating occurrences of accumulated wood. We also used this metric to quantify the overall extent of wood 'organization' in streams, which revealed similarities and differences in instream wood distribution patterns in the two regions evaluated. Wood distribution patterns in both study regions were generally consistent with our expectations of increased organization at an intermediate stream size (up to 10 m bankfull width), then in larger streams (N 10 m) wood was less organized. These observed patterns result from landscape and ecosystem influences upon wood accumulation and movement in streams

Effects of stocked trout on stream invertebrate communities

Brown trout (Salmo trutta) are commonly stocked in streams and rivers worldwide to enhance recreational fisheries, but this practice can adversely impact other organisms in these ecosystems. We used nonmetric multi-dimensional scaling ordinations to evaluate the response of the invertebrate community to trout stocking in two streams in New York State. Most importantly, we used estimates of trout population mortality (natural and harvest mortality rates) to inform the timeframe within which the invertebrate response was evaluated because the potential impact of trout stocking is highly dependent on the abundance of stocked trout. We found that although brown trout are stocked at greater densities than native brook trout (Salvelinus fontinalis) the mortality rate of stocked trout was high (0.15 daily mortality rate which corresponds to 99.9% annual mortality), thus predatory impacts of fish upon invertebrates were likely to be pulsed and could only occur within a short temporal period. Despite the high mortality rate of stocked brown trout, we found a significant multivariate divergence of invertebrate community structure within two months of trout stocking in both streams

Stream fish assemblages in relation to landscape position and local habitat variables

Abstract.-The relative influence of local habitat variables and stream network position on fish assemblages was evaluated in this study of first-order through third-order streams within the Beaverkill-Willowemoc watershed in New York. We compared fish distribution and abundance over local and landscape scales by surveying 69 randomly selected tributaries within this 775-km 2 watershed. We used watershed-level metrics of stream link magnitude, branch link, confluence link, downstream link, and stream order to evaluate the importance of stream network position upon fish assemblages. Results of canonical correspondence analysis indicated that six factors significantly influenced fish species abundance in our study watershed. The proportion of fine substrate, canopy cover, in-stream vegetation, and water temperature were the four local habitat factors related to the abundance of fish species in this watershed; confluence link and stream order were the stream network position measures with the greatest influence on fish assemblages. Our results show that stream fish assemblages in the study watershed were influenced by a combination of small-scale habitat variables and stream position within a watershed network. The significance of confluence link relative to that of other link measures designed to evaluate stream network position has never been previously established in a direct comparison. The usefulness of confluence link to characterize fish assemblages is consistent with efforts to identify metrics that are relevant to both watershed network geomorphology and ecology

Diet Niche Width and Individual Specialization of Brook Trout in Adirondack Lakes

<p>We evaluated diet niche width, individual diet specialization, and diet composition in six lake populations of Brook Trout <i>Salvelinus fontinalis</i>, a generalist predator known to exhibit benthic and pelagic trophic specialization. Population diet niche width was broad and similar across all lakes, contrasting with that of individual fish, which exhibited specialized diets in comparison with their population and other individuals. Overall, the degree of individual diet specialization was high compared with that of other fishes. The degree of individual diet specialization did not differ among study populations, although it was generally reduced in spring. Individual diet specialization was consistent across fish sizes despite observed shifts in diet composition with increasing fish length. Population diet composition varied among lakes but was consistent within lakes in all years during the 3-year study period with regard to season and fish size. The consistency and stability in measures of population diet niche width, degree of individual diet specialization, and population diet composition for Brook Trout indicate that these metrics provide useful tools for characterizing fish foraging and measuring how it changes in response to biotic and abiotic perturbations.</p> <p>Received August 11, 2016; accepted January 20, 2017 Published online May 22, 2017</p