Maternal xNorrin, a Canonical Wnt Signaling Agonist and TGF-β Antagonist, Controls Early Neuroectoderm Specification in Xenopus

Xenopus maternal Norrin, which activates Wnt signaling but inhibits TGF-β family molecules, is essential for neuroectoderm formation. Loss of TGF-β inhibition in Norrin may contribute to the development of Norrie disease

Resistance of Arctic phytoplankton to ocean acidification and enhanced irradiance

The Arctic Ocean is a region particularly prone to ongoing ocean acidification (OA) and climate-driven changes. The influence of these changes on Arctic phytoplankton assemblages, however, remains poorly understood. In order to understand how OA and enhanced irradiances (e.g., resulting from sea–ice retreat) will alter the species composition, primary production, and ecophysiology of Arctic phytoplankton, we conducted an incubation experiment with an assemblage from Baffin Bay (71°N, 68°W) under different carbonate chemistry and irradiance regimes. Seawater was collected from just below the deep Chl a maximum, and the resident pytoplankton were exposed to 380 and 1000 latm pCO2 at both 15 and 35% incident irradiance. On-deck incubations, in which temperatures were 6°C above in situ conditions, were monitored for phytoplankton growth, biomass stoichiometry, net primary production, photo-physiology, and taxonomic composition. During the 8-day experiment, taxonomic diversity decreased and the diatom Chaetoceros socialis became increasingly dominant irrespective of light or CO2 levels. We found no statistically significant effects from either higher CO2 or light on physiological properties of phytoplankton during the experiment. We did, however, observe an initial 2-day stress response in all treatments, and slight photo-physiological responses to higher CO2 and light during the first five days of the incubation. Our results thus indicate high resistance of Arctic phytoplankton to OA and enhanced irradiance levels, challenging the commonly predicted stimulatory effects of enhanced CO2 and light availability for primary production

Combined effects of ocean acidification and enhanced irradiances on Arctic phytoplankton assemblages from different locations – why do they not care?

The Arctic Ocean is one of the regions most prone to on-going ocean acidification (OA) and climate-driven changes, including increased sea surface temperature, sea-ice melt and altered mixing regimes. However, the influence of these changes on Arctic primary productivity, phytoplankton ecology and elemental cycles remains poorly understood. To date, the impact of various environmental stressors on phytoplankton have largely been assessed in isolation, and only limited process-understanding was gained. In order to understand how OA and enhanced irradiances (resulting from sea-ice retreat and increased mixed layer stratification) will alter the species composition, productivity and ecophysiology of Arctic phytoplankton, we conducted four incubation experiments with natural plankton assemblages from Davis Strait (63°N), Baffin Bay (71°N) and Kongsfjorden (Svalbard, 79°N). Phytoplankton assemblages were exposed to 400 and 1200 µatm pCO2 at both low and high irradiance levels over several weeks. These incubations were monitored and characterised in terms of phytoplankton growth, nutrient usage, biomass stoichiometry, net primary production (NPP), photophysiology and species composition. Preliminary results indicate that while the Subarctic Davis Strait assemblage exhibited light- and CO2-dependent growth rates and NPP, while there were no such differences between treatments in the Arctic assemblages (Baffin Bay and Svalbard). The observed similarities and differences in composition, productivity and physiology of phytoplankton assemblages grown under different climate scenarios will be discussed. Overall, our results indicate a high level of resilience of Arctic primary producers to climate-dependent environmental change

Correction to: Resistance of Arctic phytoplankton to ocean acidification and enhanced irradiance

The authors regret an error in the published article, where incorrect data was used to produce Figure 2, showing the temporal development of pH over the duration of the experiment. The corrected Fig. 2 shows that the error did not affect the interpretation of nor the conclusions drawn from the present dataset. The original article has been corrected

FIVE-YEAR MORTALITY AND RELATED PROGNOSTIC FACTORS AFTER INPATIENT STROKE REHABILITATION: A EUROPEAN MULTI-CENTRE STUDY

Objective: To determine 5-year mortality and its association with baseline characteristics and functional status 6 months post-stroke for patients who received inpatient rehabilitation. Design: A prospective rehabilitation-based cohort study. Subjects: A total of 532 consecutive stroke patients from 4 European rehabilitation centres. Methods: Predictors were recorded on admission. Barthel Index was assessed at 6 months (BI6mths) and patients were followed for 5 years post-stroke. Survival probability was computed using Kaplan-Meier analysis and compared across 3 BI6mths-classes (0-60, 65-90, 95-100) (log-rank test). Significant independent predictors were determined using multivariate Cox regression analysis (hazard ratio (HR)). Results: Five-year cumulative risk of death was 29.12% (95% confidence interval (CI): 22.86-35.38). Age (HR= 1.06, 95% CI: 1.04-1.09), cognitive impairment (HR= 1.77, 95% CI: 1.21-2.57), diabetes mellitus (HR= 1.68, 95% CI: 1.16-2.41) and atrial fibrillation (HR= 1.52, 95% CI: 1.08-2.14) were independent predictors of increased mortality. Hyperlipidaemia (HR=0.66, 95% CI: 0.46-0.94), and higher BI6mths (HR=0.98, 95% CI: 0.97-0.99) were independent predictors of decreased mortality. Five-year sur Conclusion: Nearly one-third of rehabilitation patients died during the first 5 years following stroke. Functional status at 6 months was a powerful predictor of long-term mortality. Maximum functional independence at 6 months post-stroke should be promoted through medical interventions and rehabilitation. Future studies are recommended to evaluate the direct effect of rehabilitation on long-term survival

Anxiety and depression after stroke: a 5 year follow-up

Purpose: The aim was to document the prevalence and predictors of anxiety and depression 5 years after stroke, across four European centres. Method: A cohort of 220 stroke patients was assessed at 2, 4 and 6 months and 5 years after stroke. Patients were assessed on the Hospital Anxiety and Depression Scale and measures of motor function and independence in activities of daily living. Results: At 5 years, the prevalence of anxiety was 29% and depression 33%, with no significant differences between centres. The severity of anxiety and depression increased significantly between 6 months and 5 years. Higher anxiety at 6 months and centre were significantly associated with anxiety at 5 years, but not measures of functional recovery. Higher depression scores at 6 months, older age and centre, but not measures of functional recovery, were associated with depression at 5 years. Conclusions: Anxiety and depression were more frequent at 5 years after stroke than at 6 months. There were significant differences between four European centres in the severity of anxiety and depression. Although the main determinant of anxiety or depression scores at 5 years was the level of anxiety or depression at 6 months, this accounted for little of the variance. Centre was also a significant predictor of mood at 5 years. There needs to be greater recognition of the development of mood disorders late after stroke and evaluation of variation in management policies across centres. Implications for Rehabilitation Depression and anxiety persisted up to 5 years after stroke in about a third of patients. Variation in the rates of anxiety and depression between different European centres suggest management policies rather than stroke related factors may determine their persistence. The effect of variations in stroke management policies should be investigated. Patients' mood should be monitored over time in order to detect those with late onset mood disorders after stroke