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Bumblebees are essential pollinators of crops and wild plants, but are in decline across the globe. Neonicotinoid pesticides have been implicated as a potential driver of these declines, but most of our evidence base comes from studies of a single species. There is an urgent need to understand whether such results can be generalized across a range of species. Here, we present results of a laboratory experiment testing the impacts of field-relevant doses (1.87–5.32 ppb) of the neonicotinoid thiamethoxam on spring-caught wild queens of four bumblebee species: Bombus terrestris, B. lucorum, B. pratorum and B. pascuorum. Two weeks of exposure to the higher concentration of thiamethoxam caused a reduction in feeding in two out of four species, suggesting species-specific anti-feedant, repellency or toxicity effects. The higher level of thiamethoxam exposure resulted in a reduction in the average length of terminal oocytes in queens of all four species. In addition to providing the first evidence for general effects of neonicotinoids on ovary development in multiple species of wild bumblebee queens, the discovery of species-specific effects on feeding has significant implications for current practices and policy for pesticide risk assessment and use.

Pollinators are in global decline and agricultural pesticides are a potential driver of this. Recent studies have suggested that pesticides may significantly impact bumblebee colonies—an important and declining group of pollinators. Here, we show that colony-founding queens, a critical yet vulnerable stage of the bumblebee lifecycle, are less likely to initiate a colony after exposure to thiamethoxam, a neonicotinoid insecticide. Bombus terrestris queens were exposed to field-relevant levels of thiamethoxam and two natural stressors: the parasite Crithidia bombi and varying hibernation durations. Exposure to thiamethoxam caused a 26% reduction in the proportion of queens that laid eggs, and advanced the timing of colony initiation, although we did not detect impacts of any experimental treatment on the ability of queens to produce adult offspring during the 14-week experimental period. As expected from previous studies, the hibernation duration also had an impact on egg laying, but there was no significant interaction with insecticide treatment. Modelling the impacts of a 26% reduction in colony founding on population dynamics dramatically increased the likelihood of population extinction. This shows that neonicotinoids can affect this critical stage in the bumblebee lifecycle and may have significant impacts on population dynamics. Thiamethoxam, a neonicotinoid pesticide, is shown to reduce the rate of colony initiation by bumblebee queens. Modelling shows that this effect could increase colony extinction rates.

1. Bees are exposed to pesticides when foraging in agricultural areas and growing evidence suggests that such compounds can be harmful to managed and wild populations. Given the economic and ecological importance of bees, and the evidence of widespread population declines, the full impacts of pesticides and their interactions with other stressors in the environment need to be investigated. 2. Here, we focus on the impacts of chronic exposure to the commonly used pyrethroid pesticide lambda (λ)-cyhalothrin on the bumblebee Bombus terrestris at both the individual and colony level. Furthermore, we investigated the interactions of pesticide exposure with a highly prevalent trypanosome parasite Crithidia bombi. Colonies were exposed to λ-cyhalothrin in the laboratory, and colony growth and reproductive output were monitored for up to 14 weeks. The potential interactions between the pesticide and C. bombi were investigated by quantifying the impact of pesticide treatment on susceptibility to, and success of experimental infections, as well as the survival of workers. Male survival after larval pesticide exposure was also monitored. 3. Pesticide-treated colonies produced workers with a significantly lower body mass. However, out of the twelve variables of colony development measured, this was the only metric that was significantly affected by pesticide treatment and there was no subsequent significant impact on the reproductive output of colonies. 4. Lambda-cyhalothrin had no significant impact on the susceptibility of workers to C. bombi, or intensity of parasitic infection. 5. Pesticide exposure did not cause differential survival in workers or males, even when workers were additionally challenged with C. bombi. 6. Synthesis and applications. Chronic exposure to λ-cyhalothrin has a significant impact on worker size, a key aspect of bumblebee colony function, particularly under conditions of limited food resources. This could indicate that under times of resource limitation, colonies exposed to this pesticide in the field may fail. However, the lack of other impacts found in this study indicate that further field trials are needed to elucidate this.

Bumblebees are essential pollinators of crops and wild plants, but are in decline across the globe. Neonicotinoid pesticides have been implicated as a potential driver of these declines, but most of our evidence base comes from studies of a single species. There is an urgent need to understand whether such results can be generalized across a range of species. Here, we present results of a laboratory experiment testing the impacts of fieldrelevant doses (1.87-5.32 ppb) of the neonicotinoid thiamethoxam on spring-caught wild queens of four bumblebee species: Bombus terrestris, B. lucorum, B. pratorum and B. pascuorum. Two weeks of exposure to the higher concentration of thiamethoxam caused a reduction in feeding in two out of four species, suggesting species-specific anti-feedant, repellency or toxicity effects. The higher level of thiamethoxam exposure resulted in a reduction in the average length of terminal oocytes in queens of all four species. In addition to providing the first evidence for general effects of neonicotinoids on ovary development in multiple species of wild bumblebee queens, the discovery of species-specific effects on feeding has significant implications for current practices and policy for pesticide risk assessment and use.

ObjectiveWe sought to develop the first Damage Index (DI) in systemic sclerosis (SSc).MethodsThe conceptual definition of ‘damage’ in SSc was determined through consensus by a working group of the Scleroderma Clinical Trials Consortium (SCTC). Systematic literature review and consultation with patient partners and non-rheumatologist experts produced a list of potential items for inclusion in the DI. These steps were used to reduce the items: (1) Expert members of the SCTC (n=331) were invited to rate the appropriateness of each item for inclusion, using a web-based survey. Items with >60% consensus were retained; (2) Using a prospectively acquired Australian cohort data set of 1568 patients, the univariable relationships between the remaining items and the endpoints of mortality and morbidity (Physical Component Summary score of the Short Form 36) were analysed, and items with p<0.10 were retained; (3) using multivariable regression analysis, coefficients were used to determine a weighted score for each item. The DI was externally validated in a Canadian cohort.ResultsNinety-three (28.1%) complete survey responses were analysed; 58 of 83 items were retained. The univariable relationships with death and/or morbidity endpoints were statistically significant for 22 items, with one additional item forced into the multivariable model by experts due to clinical importance, to create a 23-item weighted SCTC DI (SCTC-DI). The SCTC-DI was predictive of morbidity and mortality in the external cohort.ConclusionsThrough the combined use of consensus and data-driven methods, a 23-item SCTC-DI was developed and retrospectively validated.

Pyruvate dehydrogenase (PDH) is the gatekeeper enzyme of the tricarboxylic acid (TCA) cycle. Here we show that the deglycase DJ-1 (encoded by PARK7 , a key familial Parkinson’s disease gene) is a pacemaker regulating PDH activity in CD4 + regulatory T cells (T reg cells). DJ-1 binds to PDHE1-β (PDHB), inhibiting phosphorylation of PDHE1-α (PDHA), thus promoting PDH activity and oxidative phosphorylation (OXPHOS). Park7 ( Dj-1 ) deletion impairs T reg survival starting in young mice and reduces T reg homeostatic proliferation and cellularity only in aged mice. This leads to increased severity in aged mice during the remission of experimental autoimmune encephalomyelitis (EAE). Dj-1 deletion also compromises differentiation of inducible T reg cells especially in aged mice, and the impairment occurs via regulation of PDHB. These findings provide unforeseen insight into the complicated regulatory machinery of the PDH complex. As T reg homeostasis is dysregulated in many complex diseases, the DJ-1–PDHB axis represents a potential target to maintain or re-establish T reg homeostasis. In this work, Danileviciute, Zeng et al. provide new insights into the regulation of the PDH complex by PARK7/DJ-1 and show its relevance in T reg homeostasis during ageing.

IntroductionTo assess the management of immunocompetent patients with primary central nervous system lymphomas (PCNSL) in Spain.MethodsRetrospective analysis of 327 immunocompetent patients with histologically confirmed PCNSL diagnosed between 2005 and 2014 in 27 Spanish hospitals.ResultsMedian age was 64 years (range: 19–84; 33% ≥ 70 years), 54% were men, and 59% had a performance status (PS) ≥ 2 at diagnosis. Median delay to diagnosis was 47 days (IQR 24–81). Diagnostic delay > 47 days was associated with PS ≥ 2 (OR 1.99; 95% CI 1.13–3.50; p = 0.016) and treatment with corticosteroids (OR 2.47; 95% CI 1.14–5.40; p = 0.023), and it did not improve over the years. Patients treated with corticosteroids (62%) had a higher risk of additional biopsies (11.7% vs 4.0%, p = 0.04) but corticosteroids withdrawal before surgery did not reduce this risk and increased the diagnostic delay (64 vs 40 days, p = 0.04). Median overall survival (OS) was 8.9 months [95% CI 5.9–11.7] for the whole series, including 52 (16%) patients that were not treated, and 14.1 months (95%CI 7.7–20.5) for the 240 (73.4%) patients that received high-dose methotrexate (HD-MTX)-based chemotherapy. Median OS was shorter in patients ≥ 70 years (4.1 vs. 13.4 months; p < 0.0001). Multivariate analysis identified age ≥ 65 years, PS ≥ 2, no treatment, and cognitive/psychiatric symptoms at diagnosis as independent predictors of short survival.ConclusionsCorticosteroids withdrawal before surgery does not decrease the risk of a negative biopsy but delays diagnosis. In this community-based study, only 73.4% of patients could receive HD-MTX-based chemotherapy and OS remains poor, particularly in elderly patients ≥ 70 years.

Pyruvate dehydrogenase (PDH) is the gatekeeper enzyme of the tricarboxylic acid (TCA) cycle. Here we show that the deglycase DJ-1 (encoded by PARK7, a key familial Parkinson's disease gene) is a pacemaker regulating PDH activity in CD4 regulatory T cells (T cells). DJ-1 binds to PDHE1-β (PDHB), inhibiting phosphorylation of PDHE1-α (PDHA), thus promoting PDH activity and oxidative phosphorylation (OXPHOS). Park7 (Dj-1) deletion impairs T survival starting in young mice and reduces T homeostatic proliferation and cellularity only in aged mice. This leads to increased severity in aged mice during the remission of experimental autoimmune encephalomyelitis (EAE). Dj-1 deletion also compromises differentiation of inducible T cells especially in aged mice, and the impairment occurs via regulation of PDHB. These findings provide unforeseen insight into the complicated regulatory machinery of the PDH complex. As T homeostasis is dysregulated in many complex diseases, the DJ-1-PDHB axis represents a potential target to maintain or re-establish T homeostasis.

Abstract Objectives Fatigue can be a disabling symptom of inflammatory rheumatic diseases. LIFT (Lessening the Impact of Fatigue in inflammatory rheumatic diseases: a randomized Trial) is a randomized trial of remotely delivered cognitive-behavioural approach or personalized exercise programme interventions, compared with usual care. The aim of this nested qualitative study was to evaluate participants’ experiences of taking part in the intervention, including their ideas about future service delivery. Methods Semi-structured telephone interviews were conducted with a subgroup of LIFT participants to discuss their views and experiences of the interventions. Results Forty-three participants (30 women) from six sites who had participated in the cognitive-behavioural approach (n = 22) or personalized exercise programme (n = 21) interventions took part. Five themes were identified in the thematic analysis. In the theme ‘not a miracle cure, but a way to better manage fatigue’, LIFT could not cure fatigue; however, most felt better able to manage after participating. Participants valued ‘building a therapeutic relationship’ with the same therapist throughout the intervention. In ‘structure, self-monitoring and being accountable’, participants liked the inclusion of goal-setting techniques and were motivated by reporting back to the therapist. After taking part in the interventions, participants felt ‘better equipped to cope with fatigue’; more confident and empowered. Lastly, participants shared ideas for ‘a tailored programme delivered remotely’, including follow-up sessions, video calling, and group-based sessions for social support. Conclusion Many participants engaged with the LIFT interventions and reported benefits of taking part. This suggests an important future role for the remote delivery of fatigue self-management. Lay Summary What does this research mean for patients? Fatigue can be a disabling symptom in inflammatory rheumatic diseases (IRDs). The LIFT study (Lessening the Impact of Fatigue in inflammatory rheumatic diseases: a randomized Trial) looked at different interventions; a cognitive-behavioural approach (CBA), a personalized exercise programme (PEP) or usual care. CBA sessions addressed unhelpful thoughts and feelings. The PEP sessions supported people with IRDs to increase their exercise levels gradually. People with IRDs were randomly selected to take part in seven sessions of CBA, seven sessions of PEP or usual care. All sessions except the first PEP session were delivered remotely by telephone. The aim of this study was to explore people’s experiences of taking part. Forty-three people with IRDs (30 women and 13 men) were interviewed from six UK locations. Twenty-two took part in the CBA sessions, and 21 took part in PEP. People with IRDs who took part in LIFT told us about a range of benefits. These included feeling less fatigue and more confidence. Those in PEP told us they felt stronger. People with IRDs shared that they liked being able to talk about their fatigue with a supportive therapist. These are encouraging results for remotely delivered research to support people with fatigue.

Pyruvate dehydrogenase (PDH) is the gatekeeper enzyme into the tricarboxylic acid (TCA) cycle. Here we show that PARK7/DJ-1, a key familial Parkinsons, disease (PD) gene, is a pacemaker controlling PDH activity in CD4 regulatory T cells (Tregs). DJ-1 bound to PDH-E1 beta (PDHB), inhibiting the phosphorylation of PDH-E1 alpha (PDHA), thus promoting PDH activity and oxidative phosphorylation (OXPHOS). Dj-1 depletion impaired Treg proliferation and cellularity maintenance in older mice, increasing the severity during the remission phase of experimental autoimmune encephalomyelitis (EAE). The compromised proliferation and differentiation of Tregs in Dj-1 knockout mice were caused via regulating PDH activity. These findings provide novel insight into the already complicated regulatory machinery of the PDH complex and demonstrate that the DJ-1-PDHB axis represents a potent target to maintain Treg homeostasis, which is dysregulated in many complex diseases.