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Chemical transformation triggered by an electron donor–acceptor (EDA) complex without the addition of an exogenous stoichiometric electron donor/acceptor is rare. Herein, we report such a process to access 2,3-difunctionalized pyridines from readily available N-aminopyridiniums (1) and activated alkenes (2) promoted by visible light. This procedure offered multi-substituted pyridines in satisfactory yields at room temperature with broad functional group tolerance. The reaction can be easily performed on a gram scale without the loss of yield. The modification of bioactive molecules including derivatives of clinical drugs and natural products was demonstrated. Mechanistic studies and DFT calculations indicated that the formal [3 + 2] cycloaddition and aza-Michael addition between 1 and 2 generated tetrahydropyrazolo[1,5-a]pyridine and a new pyridinium salt, respectively. These two intermediates formed an EDA complex, which under visible-light illumination, triggered the following single electron transfer (SET)/N–N bond cleavage/C–N bond formation cascade process with high atom economy. [ABSTRACT FROM AUTHOR]

Aims: Systematic annual screening to detect sight‐threatening diabetic retinopathy (STDR) is established in the United Kingdom. We designed an observational cohort study to provide up‐to‐date data for policy makers and clinical researchers on incidence of key screening endpoints in people with diabetes attending one screening programme running for over 30 years. Methods: All people with diabetes aged ≥12 years registered with general practices in the Liverpool health district were offered inclusion. Data sources comprised: primary care (demographics, systemic risk factors), Liverpool Diabetes Eye Screening Programme (retinopathy grading), Hospital Eye Services (slit lamp biomicroscopy assessment of screen positives). Results: 133,366 screening episodes occurred in 28,384 people over 11 years. Overall incidences were: screen positive 6.7% (95% CI 6.5–6.8), screen positive for retinopathy 3.1% (3.0–3.1), unassessable images 2.6% (2.5–2.7), other significant eye diseases 1.0% (1.0–1.1). 1.6% (1.6–1.7) had sight‐threatening retinopathy confirmed by slit lamp biomicroscopy. The annual incidence of screen positive and screen positive for retinopathy showed consistent declines from 8.8%–10.6% and 4.4%–4.6% in 2007/09 to 4.4%–6.8% and 2.3%–2.9% in 2013/17, respectively. Rates of STDR (true positive) were consistently below 2% after 2008/09. Screen positive rates were higher in first time attenders (9.9% [9.4–10.2] vs. 6.1% [6.0–6.2]) in part due to ungradeable images (4.1% vs. 2.3%) and other eye disease (2.4% vs. 0.8%). 4.5% (3.9–5.2) of previous non‐attenders had sight‐threatening retinopathy. Compared with people with type 2 diabetes, those with type 1 disease demonstrated higher rates of screen positive (11.9% vs. 6.0%) and STDR (6.4% vs. 1.2%). Overall prevalence of any retinopathy was 27.2% (27.0–27.4). Conclusions: In an established screening programme with a stable population screen, positive rates show a consistent fall over time to a low level. Of those who are screen positive, fewer than 50% are screen positive for diabetic retinopathy. Most are due to sight threatening maculopathy. The annual incidence of STDR is under 2% suggesting future work on redefining screen positive and supporting extended intervals for people at low risk. Higher rates of screen positive and STDR are seen in first time attenders. Those who have never attended for screening should be specifically targeted. [ABSTRACT FROM AUTHOR]

Aims: To evaluate our proposed multivariate approach to identify patients who will develop sight‐threatening diabetic retinopathy (STDR) within a 1‐year screen interval, and explore the impact of simple stratification rules on prediction. Materials and methods: A 7‐year dataset (2009‐2016) from people with diabetes (PWD) was analysed using a novel multivariate longitudinal discriminant approach. Level of diabetic retinopathy, assessed from routine digital screening photographs of both eyes, was jointly modelled using clinical data collected over time. Simple stratification rules based on retinopathy level were also applied and compared with the multivariate discriminant approach. Results: Data from 13 103 PWD (49 520 screening episodes) were analysed. The multivariate approach accurately predicted whether patients developed STDR or not within 1 year from the time of prediction in 84.0% of patients (95% confidence interval [CI] 80.4‐89.7), compared with 56.7% (95% CI 55.5‐58.0) and 79.7% (95% CI 78.8‐80.6) achieved by the two stratification rules. While the stratification rules detected up to 95.2% (95% CI 92.2‐97.6) of the STDR cases (sensitivity) only 55.6% (95% CI 54.5‐56.7) of patients who did not develop STDR were correctly identified (specificity), compared with 85.4% (95% CI 80.4‐89.7%) and 84.0% (95% CI 80.7‐87.6%), respectively, achieved by the multivariate risk model. Conclusions: Accurate prediction of progression to STDR in PWD can be achieved using a multivariate risk model whilst also maintaining desirable specificity. While simple stratification rules can achieve good levels of sensitivity, the present study indicates that their lower specificity (high false‐positive rate) would therefore necessitate a greater frequency of eye examinations. [ABSTRACT FROM AUTHOR]

Background: Varying the intervals in retinopathy screening informed by personal risk offers reallocation of resources to better target high risk groups and address the increasing prevalence of diabetes. However, safety data especially on extended intervals is minimal. Aim: To evaluate the safety, efficacy and cost effectiveness (CE) of individualized variable-interval risk-based screening in a population setting compared to usual care. Methods: Masked 2 arm, parallel assignment, equivalence RCT (largest to date in screening) with independent trials unit monitoring in people with diabetes aged ≥12 years attending screening in a single English program. Randomization was 1:1 to individualized screening (active group; 6, 12 or 24 months for high, medium and low risk) determined by a risk calculation engine using real-time local demographic, retinal and clinical data, compared with annual screening (control). CE analysis measuring NHS and societal costs took a 2-year time horizon. Findings: 4534 participants entered the study - after withdrawals/loss to follow-up: active 2097; control 2224. Attendance rates at first follow-up visit (primary outcome, safety) were equivalent (per protocol analysis, 5% margin): active 83.6% control 84.7% (difference 1.0, 90% CI -0.8, 2.9). STDR detection rates were non-inferior (1.5% margin): active 1.43% control 1.71% (difference -0.28, CI -0.93, 0.36). Quality of life (EQ5D5L, HUI3) was not significantly different between the groups. Incremental cost saving per person was £18.75 (NHS cost) rising to £49.96 with societal costs. A 39.3% reduction in number of appointments was seen. Conclusions: All parties involved in diabetes care can be reassured that extended and personalized screening intervals can safely be introduced in established screening program. Scale-up with further validation outside a research setting is recommended. Views expressed are solely those of the authors. Disclosure: D.M. Broadbent: None. A. Wang: None. C.P. Cheyne: None. J.G. Lathe: None. I.M. Stratton: Consultant; Self; Novo Nordisk A/S. Research Support; Self; Bayer AG, Boehringer Ingelheim International GmbH. J. Vora: None. M. Garcia-Finana: None. M. James: None. S.P. Harding: None. Funding: UK National Institute for Health Research [ABSTRACT FROM AUTHOR]

A TEMPO-mediated [3 + 2] annulation-aromatization protocol for the preparation of pyrazolo[1,5- a ]pyridines from N -aminopyridines and α,β-unsaturated compounds was developed. The procedure offered multisubstituted pyrazolo[1,5- a ]pyridines in good to excellent yield with high and predictable regioselectivity. The modification of marketed drugs including Loratadine, Abiraterone, and Metochalcone, and a one-pot three-step gram scale synthesis of key intermediate for the preparation of Selpercatinib were demonstrated. Mechanism studies show that TEMPO serves both as a Lewis acid and as an oxidant.

Aims/hypothesis: Using variable diabetic retinopathy screening intervals, informed by personal risk levels, offers improved engagement of people with diabetes and reallocation of resources to high-risk groups, while addressing the increasing prevalence of diabetes. However, safety data on extending screening intervals are minimal. The aim of this study was to evaluate the safety and cost-effectiveness of individualised, variable-interval, risk-based population screening compared with usual care, with wide-ranging input from individuals with diabetes., Methods: This was a two-arm, parallel-assignment, equivalence RCT (minimum 2 year follow-up) in individuals with diabetes aged 12 years or older registered with a single English screening programme. Participants were randomly allocated 1:1 at baseline to individualised screening at 6, 12 or 24 months for those at high, medium and low risk, respectively, as determined at each screening episode by a risk-calculation engine using local demographic, screening and clinical data, or to annual screening (control group). Screening staff and investigators were observer-masked to allocation and interval. Data were collected within the screening programme. The primary outcome was attendance (safety). A secondary safety outcome was the development of sight-threatening diabetic retinopathy. Cost-effectiveness was evaluated within a 2 year time horizon from National Health Service and societal perspectives., Results: A total of 4534 participants were randomised. After withdrawals, there were 2097 participants in the individualised screening arm and 2224 in the control arm. Attendance rates at first follow-up were equivalent between the two arms (individualised screening 83.6%; control arm 84.7%; difference -1.0 [95% CI -3.2, 1.2]), while sight-threatening diabetic retinopathy detection rates were non-inferior in the individualised screening arm (individualised screening 1.4%, control arm 1.7%; difference -0.3 [95% CI -1.1, 0.5]). Sensitivity analyses confirmed these findings. No important adverse events were observed. Mean differences in complete case quality-adjusted life-years (EuroQol Five-Dimension Questionnaire, Health Utilities Index Mark 3) did not significantly differ from zero; multiple imputation supported the dominance of individualised screening. Incremental cost savings per person with individualised screening were £17.34 (95% CI 17.02, 17.67) from the National Health Service perspective and £23.11 (95% CI 22.73, 23.53) from the societal perspective, representing a 21% reduction in overall programme costs. Overall, 43.2% fewer screening appointments were required in the individualised arm., Conclusions/interpretation: Stakeholders involved in diabetes care can be reassured by this study, which is the largest ophthalmic RCT in diabetic retinopathy screening to date, that extended and individualised, variable-interval, risk-based screening is feasible and can be safely and cost-effectively introduced in established systematic programmes. Because of the 2 year time horizon of the trial and the long time frame of the disease, robust monitoring of attendance and retinopathy rates should be included in any future implementation., Trial Registration: ISRCTN 87561257 FUNDING: The study was funded by the UK National Institute for Health Research. Graphical abstract.

Coordinated migratory events are required for the development of effective and regulated immunity. Naïve T lymphocytes are programmed to recirculate predominantly in secondary lymphoid tissue by non-specific stimuli. In contrast, primed T cells must identify specific sites of antigen location in non-lymphoid tissue to exert targeted effector responses. Following priming, T cells acquire the ability to establish molecular interactions mediated by tissue-selective adhesion and chemokine receptors (homing receptors) that facilitate their access to specific organs. Recent studies have shown that an additional level of homing specificity is provided by the induction of T cell migration into the tissue by recognition of antigen displayed by the endothelium. In addition, co-stimulatory signals have been recently shown not only to regulate T cell activation and differentiation, but also to orchestrate the anatomy of the ensuing T cell response. Similarly, the characterization of migratory patterns by regulatory T cells has been the subject of many recent studies. Here, we provide an overview of key concepts, which have contribute to unraveling the complex anatomy of T cell immunity.