Addressing challenges in the removal of unbound dye from passively labelled extracellular vesicles

Correction: 10.1039/d1na90120fStudies of extracellular vesicles (EVs), their trafficking and characterization often employ fluorescent labelling. Unfortunately, little attention has been paid thus far to a thorough evaluation of the purification of EVs after labelling, although the presence of an unbound dye may severely compromise the results or even lead to wrong conclusions on EV functionality. Here, we systematically studied five dyes for passive EV labelling and meticulously compared five typical purification methods: ultracentrifugation (UC), ultracentrifugation with discontinuous density gradient (UCG), ultrafiltration (UF), size exclusion chromatography (SEC), and anion exchange chromatography (AEC). A general methodology for evaluation of EV purification efficiency after the labelling was developed and tested to select the purification methods for the chosen dyes. Firstly, we found that some methods initially lead to high EV losses even in the absence of the dye. Secondly, the suitable purification method needs to be found for each particular dye and depends on the physical and chemical properties of the dye. Thirdly, we demonstrated that the developed parameter E-rp (relative purification efficiency) is a useful tool for the pre-screening of the suitable dye-purification method combinations. Additionally, it was also shown that the labelled EVs properly purified from the unbound dye may show significantly reduced contrast and visibility in the target application, e.g. in the live cell fluorescence lifetime imaging.Peer reviewe

Vertebral anti-fracture efficacy of strontium ranelate according to pre-treatment bone turnover

Osteoporotic post-menopausal women patients in two randomised trials comparing the anti-fracture efficacy of strontium ranelate with placebo were separated into tertiles according to their baseline levels of biochemical markers of bone formation and resorption. The vertebral anti-fracture efficacy of strontium ranelate was shown to be independent of baseline bone turnover levels. INTRODUCTION: Bone turnover (BTO) levels vary among women at risk of osteoporotic fracture. Strontium ranelate is an anti-osteoporotic treatment increasing bone formation and reducing bone resorption. It was hypothesised that its anti-fracture efficacy would be independent of baseline BTO levels. METHODS: Post-menopausal women with osteoporosis from two pooled studies were stratified in tertiles according to baseline levels of two BTO markers: bone-specific alkaline phosphatase (b-ALP, n = 4995) and serum C-telopeptide cross-links (sCTX, n = 4891). Vertebral fracture risk was assessed over 3 years with strontium ranelate 2 g/day or placebo. RESULTS: In the placebo group, relative risk of vertebral fractures increased with BTO tertiles by 32% and 24% for patients in the highest tertile for b-ALP and CTX, respectively, compared to those in the lowest tertile. In the strontium ranelate group, incidences of vertebral fracture did not differ significantly across BTO tertiles. Significant reductions in vertebral fractures with strontium ranelate were seen in all tertiles of both markers, with relative risk reductions of 31% to 47% relative to placebo. Risk reduction did not differ among tertiles (b-ALP: p = 0.513; sCTX: p = 0.290). CONCLUSION: The vertebral anti-fracture efficacy of strontium ranelate was independent of baseline BTO levels. Strontium ranelate offers clinical benefits to women across a wide range of metabolic states

Habitat effects on the breeding performance of three forest-dwelling hawks

PLoS ONE 10(9): e0137877Habitat loss causes population declines, but the mechanisms are rarely known. In the European Boreal Zone, loss of old forest due to intensive forestry is suspected to cause declines in forest-dwelling raptors by reducing their breeding performance. We studied the boreal breeding habitat and habitat-associated breeding performance of the northern goshawk (Accipiter gentilis), common buzzard (Buteo buteo) and European honey buzzard (Pernis apivorus). We combined long-term Finnish bird-of-prey data with multi-source national forest inventory data at various distances (100–4000 m) around the hawk nests. We found that breeding success of the goshawk was best explained by the habitat within a 2000-m radius around the nests; breeding was more successful with increasing proportions of old spruce forest and water, and decreasing proportions of young thinning forest. None of the habitat variables affected significantly the breeding success of the common buzzard or the honey buzzard, or the brood size of any of the species. The amount of old spruce forest decreased both around goshawk and common buzzard nests and throughout southern Finland in 1992–2010. In contrast, the area of young forest increased in southern Finland but not around hawk nests. We emphasize the importance of studying habitats at several spatial and temporal scales to determine the relevant species-specific scale and to detect environmental changes. Further effort is needed to reconcile the socioeconomic and ecological functions of forests and habitat requirements of old forest specialists.Peer reviewe

Patient Outcomes after Heart Transplantation in Sweden between 1988 and 2017 : Continuous Improvement in Survival

PURPOSE: To investigate the survival of heart transplant (HTx) recipients during different time periods in Sweden. We hypothesized that the survival for HTx recipients has improved following advancements in the management of these patients. METHODS: Data was obtained through the database of the organ exchange organization Scandiatransplant. All patients who underwent HTx in Sweden between Jan 1988 and Dec 2017 were included. Patients were divided into five cohorts of six-year periods each. RESULTS: A total of 1137 HTx recipients were included. Main causes of transplantation were dilated cardiomyopathy (44 %) and ischemic heart disease (18 %). Retransplantation constituted a small portion of the overall total (2 %). The cohorts were similar in terms of age and gender, while later cohorts had higher BMI, lower GFR and longer ischemia time (Tab. 1). The later cohorts received organs from older donors (Tab. 1). The amount of heart transplantations performed in Sweden has increased with time (Tab. 1). Log-rank test comparing the survival curves was able to show improved survival during later eras (Fig. 1). CONCLUSION: Survival among HTx recipients has significantly improved in Sweden over time, despite less favorable recipients and donor characteristics. This was related to both reduced postoperative mortality and also improved long-time survival