Development of a Micellar-Promoted Heck Reaction for the Synthesis of DNA-Encoded Libraries.

The capability of DNA encoded libraries (DELs) as a method of small molecule hit identification is becoming widely established in drug discovery. While their selection method offers advantages over more traditional means, DELs are limited by the chemistry that can be utilized to construct them. Significant advances in DNA compatible chemistry have been made over the past five years; however such procedures are still often burdened by substrate specificity and/or incomplete conversions, reducing the fidelity of the resulting libraries. One such reaction is the Heck coupling, for which current DNA-compatible protocols are somewhat unreliable. Utilizing micellar technology, we have developed a highly efficient DNA-compatible Heck reaction that proceeds on average to 95% conversion to product across a broad variety of structurally significant building blocks and multiple DNA conjugates. This work continues the application of micellar catalysis to the development of widely applicable, effective DNA-compatible reactions for use in DELs.

Micelle-Mediated Sonogashira Coupling for DNA-Encoded Library Synthesis.

DNA-Encoded Libraries (DELs) are becoming widely established as a hit identification strategy for drug discovery campaigns. Their successful application relies on the availability and efficiency of the reactions that can be carried out on DNA. These reactions should proceed with high conversion to the desired product and have a broad substrate scope to synthesise chemically diverse and drug-like DELs. The Sonogashira coupling provides a unique means of coupling an sp-hybridized carbon centre to an aryl halide and methods to achieve this reaction on DNA are highly desirable. We report the application of our micellar technology for on-DNA chemistry to the Sonogashira reaction. This method gives highly efficient conversions for the coupling of (hetero)aromatic and aliphatic alkynes to (hetero)aryl iodides and bromides allowing the preparation of highly diverse DELs.

New dimensions for hospital services and early detection of disease: a Review from the Lancet Commission into liver disease in the UK.

This Review, in addressing the unacceptably high mortality of patients with liver disease admitted to acute hospitals, reinforces the need for integrated clinical services. The masterplan described is based on regional, geographically sited liver centres, each linked to four to six surrounding district general hospitals-a pattern of care similar to that successfully introduced for stroke services. The plan includes the establishment of a lead and deputy lead clinician in each acute hospital, preferably a hepatologist or gastroenterologist with a special interest in liver disease, who will have prime responsibility for organising the care of admitted patients with liver disease on a 24/7 basis. Essential for the plan is greater access to intensive care units and high-dependency units, in line with the reconfiguration of emergency care due to the COVID-19 pandemic. This Review strongly recommends full implementation of alcohol care teams in hospitals and improved working links with acute medical services. We also endorse recommendations from paediatric liver services to improve overall survival figures by diagnosing biliary atresia earlier based on stool colour charts and better caring for patients with impaired cognitive ability and developmental mental health problems. Pilot studies of earlier diagnosis have shown encouraging progress, with 5-6% of previously undiagnosed cases of severe fibrosis or cirrhosis identified through use of a portable FibroScan in primary care. Similar approaches to the detection of early asymptomatic disease are described in accounts from the devolved nations, and the potential of digital technology in improving the value of clinical consultation and screening programmes in primary care is highlighted. The striking contribution of comorbidities, particularly obesity and diabetes (with excess alcohol consumption known to be a major factor in obesity), to mortality in COVID-19 reinforces the need for fiscal and other long delayed regulatory measures to reduce the prevalence of obesity. These measures include the food sugar levy and the introduction of the minimum unit price policy to reduce alcohol consumption. Improving public health, this Review emphasises, will not only mitigate the severity of further waves of COVID-19, but is crucial to reducing the unacceptable burden from liver disease in the UK.

On-DNA Transfer Hydrogenolysis and Hydrogenation for the Synthesis of DNA-Encoded Chemical Libraries.

DNA-encoded libraries (DELs) are an increasingly popular approach to finding small molecule ligands for proteins. Many DEL synthesis protocols hinge on sequential additions of monomers using split-pool combinatorial methods. Therefore, compatible protecting group strategies that allow the unmasking of reactive functionality (e. g. amines and alcohols) prior to monomer coupling, or the removal of less desirable functionality (e. g., alkenes and alkynes) are highly desirable. Hydrogenation/hydrogenolysis procedures would achieve these ends but have not been amenable to DEL chemistry. We report a catalytic hydrogen transfer reaction using Pd/C, HCONH4 and the micelle-forming surfactant, TPGS-750-M, which gives highly efficient conversions for hydrogenolysis of Cbz-protected amines and benzyl protected alcohols and hydrogenation of nitros, halides, nitriles, aldehydes, alkenes and alkynes. Application to multicycle synthesis of an encoded compound was fully compatible with DNA-amplification and sequencing, demonstrating its applicability to DEL synthesis. This method will enable synthetic DEL sequences using orthogonal protecting groups.

Functional Group Tolerance of a Micellar on-DNA Suzuki-Miyaura Cross-Coupling Reaction for DNA-Encoded Library Design.

DNA-encoded libraries (DELs) offer great promise for the discovery of new ligands for proteins. Many current reactions used for DEL synthesis do not proceed efficiently over a wide range of substrates. Combining a diverse array of multicomponent reactions with micellar-promoted Suzuki-Miyaura cross-coupling provides a strategy for synthesizing highly diverse DELs with exceptionally high fidelity. These results demonstrate that the micellar Suzuki-Miyaura reaction has exceptional functional group tolerance and broad applicability.

On the design of lead-like DNA-encoded chemical libraries.

DNA-encoded libraries (DELs) are becoming an established technology for finding ligands for protein targets. We have abstracted and analysed libraries from the literature to assess the synthesis strategy, selections of reactions and monomers and their propensity to reveal hits. DELs have led to hit compounds across a range of diverse protein classes. The range of reactions and monomers utilised has been relatively limited and the hits are often higher in molecular weight than might be considered ideal. Considerations for future library designs with reference to chemical diversity and lead-like properties are discussed.

Patient and family views of nutritional status.

Providing adequate food in hospitals remains a concern for those involved in healthcare as well as patients and relatives. We conducted a small-scale survey to explore relatives' and patients' perceptions about the risk of developing malnutrition in hospital and to gauge whether further more in-depth audit was required.

BSG cross-sectional survey on impact of COVID-19 recovery on workforce, workload and well-being.

Objective: The aim of this survey was to understand the impact of the COVID-19 pandemic and recovery phase on workload, well-being and workforce attrition in UK gastroenterology and hepatology. Design/method: A cross-sectional survey of British Society of Gastroenterology physician and trainee members was conducted between August and October 2021. Multivariable binary logistic regression and qualitative analyses were performed. Results: The response rate was 28.8% (180/624 of opened email invites). 38.2% (n=21/55) of those who contracted COVID-19 felt pressured to return to work before they felt ready. 43.8% (71/162) had a regular increase in out-of-hours working. This disproportionately affected newly appointed consultants (OR 5.8), those working full-time (OR 11.6), those who developed COVID-19 (OR 4.1) and those planning early retirement (OR 4.0). 92% (150/164) believe the workforce is inadequate to manage the service backlog with new consultants expressing the highest levels of anxiety over this. 49.1% (80/163) felt isolated due to remote working and 65.9% (108/164) felt reduced face-to-face patient contact made their job less fulfilling. 34.0% (55/162) planned to work more flexibly and 54.3% (75/138) of consultants planned to retire early in the aftermath of the pandemic. Early retirement was independently associated with male gender (OR 2.5), feeling isolated from the department (OR 2.3) and increased anxiety over service backlog (OR 1.02). Conclusion: The pandemic has placed an additional burden on work-life balance, well-being and workforce retention within gastroenterology and hepatology. Increased aspirations for early retirement and flexible working need to be explicitly addressed in future workforce planning.

On-DNA Transfer Hydrogenolysis and Hydrogenation for the Synthesis of DNA-Encoded Chemical Libraries.

DNA-encoded libraries (DELs) are an increasingly popular approach to finding small molecule ligands for proteins. Many DEL synthesis protocols hinge on sequential additions of monomers using split-pool combinatorial methods. Therefore, compatible protecting group strategies that allow the unmasking of reactive functionality (e. g. amines and alcohols) prior to monomer coupling, or the removal of less desirable functionality (e. g., alkenes and alkynes) are highly desirable. Hydrogenation/hydrogenolysis procedures would achieve these ends but have not been amenable to DEL chemistry. We report a catalytic hydrogen transfer reaction using Pd/C, HCONH4 and the micelle-forming surfactant, TPGS-750-M, which gives highly efficient conversions for hydrogenolysis of Cbz-protected amines and benzyl protected alcohols and hydrogenation of nitros, halides, nitriles, aldehydes, alkenes and alkynes. Application to multicycle synthesis of an encoded compound was fully compatible with DNA-amplification and sequencing, demonstrating its applicability to DEL synthesis. This method will enable synthetic DEL sequences using orthogonal protecting groups.

Highly efficient on-DNA amide couplings promoted by micelle forming surfactants for the synthesis of DNA encoded libraries.

DNA encoded libraries (DELs) represent powerful new technology for finding small molecule ligands for proteins and are increasingly being applied to hit finding in medicinal chemistry. Crucial to the synthesis of high quality DELs is the identification of chemical reactions for their assembly that proceed with very high conversion across a range of different substrates, under conditions compatible with DNA-tagged substrates. Many current chemistries used in DEL synthesis do not meet this requirement, resulting in libraries of low fidelity. Amide couplings are the most commonly used reaction in synthesis of screening libraries and also in DELs. The ability to carry out highly efficient, widely applicable amide couplings in DEL synthesis would therefore be highly desirable. We report a method for amide coupling using micelle forming surfactants, promoted by a modified linker, that is broadly applicable across a wide range of substrates. Most significantly, this works exceptionally well for coupling of DNA-conjugated carboxylic acids (N-to-C) with amines in solution, a procedure that is currently very inefficient. The optimisation of separate procedures for coupling of DNA-conjugated acids and amines by reagent screening and statistically driven optimisation is described. The generality of the method is illustrated by the application to a wide range of examples with unprecedented levels of conversion. The utility of the (N-to-C) coupling of DNA-conjugated acids in DEL synthesis is illustrated by the three cycle synthesis of a fully DNA-encoded compound by two cycles of coupling of an aminoester, with intermediate ester hydrolysis, followed by capping with an amine. This methodology will be of great utility in the synthesis of high fidelity DELs.

Later careers - regenerating the medical workforce.

We have a medical workforce crisis where we have insufficient trainees, demonstrated by rota gaps, and in turn nearly half of advertised consultant physician posts cannot be appointed to. Most physicians retire around age 62, and already 5% of the total consultant workforce is those who have retired and returned. If those reaching retirement age chose not to retire but continue working less than full time this would, at least in part, benefit the workforce and utilise valuable skills and experience to the benefit of the individual, the wider medical community and therefore our patients.

Disruption of smooth pursuit eye movements in cirrhosis: relationship to hepatic encephalopathy and its treatment.

Smooth pursuit eye movements (SPEM) are the conjugate movements used to track the smooth trajectory of small dots. Jerky or 'saccadic' ocular pursuit has been reported in patients with cirrhosis, but no formal assessment of SPEM has ever been undertaken. The aim of this study was to evaluate SPEM in patients with cirrhosis and varying degrees of hepatic encephalopathy. The patient population comprised 56 individuals (31 men, 25 women) of mean age 51.1 (range, 25-70) years, with biopsy-proven cirrhosis, classified, using clinical, electroencephalographic, and psychometric variables, as either neuropsychiatrically unimpaired or as having minimal or overt hepatic encephalopathy; patients were further categorized in relation to their treatment status. The reference population comprised 28 healthy volunteers (12 men, 16 women) of mean age 47.3 (range, 26-65) years. SPEM was assessed using an electro-oculographic technique. Visual inspection of the SPEM recordings showed clear disruption of smooth pursuit in the patients with minimal hepatic encephalopathy, and more pronounced disruption, if not complete loss, of smooth pursuit in patients with overt hepatic encephalopathy. The differences observed in quantifiable SPEM indices between the healthy volunteers/unimpaired patients and those with overt hepatic encephalopathy were significant (P < .05). In conclusion, SPEM performance is impaired in patients with hepatic encephalopathy in parallel with the degree of neuropsychiatric disturbance: the pathophysiology of these changes is unknown, but retinal, extrapyramidal, and attentional abnormalities are likely to play a role. Treatment status confounds the classification of neuropsychiatric status and should be taken into account when categorizing these patients.