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The recent advances in relative protein-ligand binding free energy calculations have shown the value of alchemical methods in drug discovery. Accurately assessing absolute binding free energies, although highly desired, remains a challenging endeavour, mostly limited to small model cases. Here, we demonstrate accurate first principles based absolute binding free energy estimates for 128 pharmaceutically relevant targets. We use a novel rigorous method to generate protein-ligand ensembles for the ligand in its decoupled state. Not only do the calculations deliver accurate protein-ligand binding affinity estimates, but they also provide detailed physical insight into the structural determinants of binding. We identify subtle rotamer rearrangements between apo and holo states of a protein that are crucial for binding. When compared to relative binding free energy calculations, obtaining absolute binding free energies is considerably more challenging in large part due to the need to explicitly account for the protein in its apo state. In this work we present several approaches to obtain apo state ensembles for accurate absolute ΔG calculations, thus outlining protocols for prospective application of the methods for drug discovery.

In binding free energy calculations, simulations must sample all relevant conformations of the system in order to obtain unbiased results. For instance, different ligands can bind to different metastable states of a protein, and if these protein conformational changes are not sampled in relative binding free energy calculations, the contribution of these states to binding is not accounted for and thus calculated binding free energies are inaccurate. In this work, we investigate the impact of different beta-sectretase 1 (BACE1) protein conformations obtained from x-ray crystallography on the binding of BACE1 inhibitors. We highlight how these conformational changes are not adequately sampled in typical molecular dynamics simulations. Furthermore, we show that insufficient sampling of relevant conformations induces substantial error in relative binding free energy calculations, as judged by a variation in calculated relative binding free energies up to 2 kcal/mol depending on the starting protein conformation. These results emphasize the importance of protein conformational sampling and pose this BACE1 system as a challenge case for further method development in the area of enhanced protein conformational sampling, either in combination with binding calculations or as an endpoint correction., (© 2024 Wiley Periodicals LLC.)

Study Objective: Management of pain after foot and ankle surgery remains a concern for patients and healthcare professionals. This study determined the effectiveness of ambulatory continuous popliteal sciatic nerve blockade, compared to standard of care, on overall benefit of analgesia score (OBAS) in patients undergoing foot or ankle surgery. We hypothesized that usage of ambulatory continuous popliteal sciatic nerve blockade is non-inferior to standard of care., Design: Single center, randomized, non-inferiority trial., Setting: Tertiary hospital in the Netherlands., Patients: Patients were enrolled if ≥18 years and scheduled for elective inpatient foot or ankle surgery., Intervention: Patients were randomized to ambulatory continuous popliteal sciatic nerve blockade or standard of care., Measurements: The primary outcome was the difference in OBAS, which includes pain, side effects of analgesics, and patient satisfaction, measured daily from the first to the third day after surgery. A non-inferiority margin of 2 was set as the upper limit for the 90% confidence interval of the difference in OBAS score. Mixed-effects modeling was employed to analyze differences in OBAS scores over time. Secondary outcome was the difference in opioid consumption., Main Results: Patients were randomized to standard of care (n = 22), or ambulatory continuous popliteal sciatic nerve blockade (n = 22). Analyzing the first three postoperative days, the OBAS was significantly lower over time in the ambulatory continuous popliteal sciatic nerve blockade group compared to standard of care, demonstrating non-inferiority (-1.9 points, 90% CI -3.1 to -0.7). During the first five postoperative days, patients with ambulatory continuous popliteal sciatic nerve blockade consumed significantly fewer opioids over time compared to standard of care (-8.7 oral morphine milligram equivalents; 95% CI -16.1 to -1.4)., Conclusions: Ambulatory continuous popliteal sciatic nerve blockade is non-inferior to standard of care with single shot popliteal sciatic nerve blockade on patient-reported overall benefit of analgesia., Competing Interests: Declaration of competing interest The authors declare no conflict of interest regarding the submitted work. Outside the submitted manuscript, MWH serves as Executive Section Editor Pharmacology with Anesthesia and Analgesia and Section Editor Anesthesiology with the Journal of Clinical Medicine, Editor with Frontiers in Physiology and he served as consultant for PAION, IDD & Medical Developments Pharma., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

Relative binding free energy (RBFE) calculations have emerged as a powerful tool that supports ligand optimization in drug discovery. Despite many successes, the use of RBFEs can often be limited by automation problems, in particular, the setup of such calculations. Atom mapping algorithms are an essential component in setting up automatic large-scale hybrid-topology RBFE calculation campaigns. Traditional algorithms typically employ a 2D subgraph isomorphism solver (SIS) in order to estimate the maximum common substructure. SIS-based approaches can be limited by time-intensive operations and issues with capturing geometry-linked chemical properties, potentially leading to suboptimal solutions. To overcome these limitations, we have developed Kartograf, a geometric-graph-based algorithm that uses primarily the 3D coordinates of atoms to find a mapping between two ligands. In free energy approaches, the ligand conformations are usually derived from docking or other previous modeling approaches, giving the coordinates a certain importance. By considering the spatial relationships between atoms related to the molecule coordinates, our algorithm bypasses the computationally complex subgraph matching of SIS-based approaches and reduces the problem to a much simpler bipartite graph matching problem. Moreover, Kartograf effectively circumvents typical mapping issues induced by molecule symmetry and stereoisomerism, making it a more robust approach for atom mapping from a geometric perspective. To validate our method, we calculated mappings with our novel approach using a diverse set of small molecules and used the mappings in relative hydration and binding free energy calculations. The comparison with two SIS-based algorithms showed that Kartograf offers a fast alternative approach. The code for Kartograf is freely available on GitHub (https://github.com/OpenFreeEnergy/kartograf). While developed for the OpenFE ecosystem, Kartograf can also be utilized as a standalone Python package.

Introduction: Low and high volume mid-thigh (ie, distal femoral triangle) and distal adductor canal block approaches are frequently applied for knee surgical procedures. Although these techniques aim to contain the injectate within the adductor canal, spillage into the popliteal fossa has been reported. While in theory this could improve analgesia, it might also result in motor blockade due to coverage of motor branches of the sciatic nerve. This radiological cadaveric study, therefore, investigated the incidence of coverage of sciatic nerve divisions after various adductor canal block techniques., Methods: Eighteen fresh, unfrozen and unembalmed human cadavers were randomized to receive ultrasound-guided distal femoral triangle or distal adductor canal injections, with 2 mL or 30 mL injectate volume, on both sides (36 blocks in total). The injectate was a 1:10 dilution of contrast medium in local anesthetic. Injectate spread was assessed using whole-body CT with reconstructions in axial, sagittal and coronal planes., Results: No coverage of the sciatic nerve or its main divisions was found. The contrast mixture spread to the popliteal fossa in three of 36 nerve blocks. Contrast reached the saphenous nerve after all injections, whereas the femoral nerve was always spared., Conclusions: Adductor canal block techniques are unlikely, even when using larger volumes, to block the sciatic nerve, or its main branches. Furthermore, injectate reached the popliteal fossa in a small minority of cases, yet if a clinical analgesic effect is achieved by this mechanism is still unknown., Competing Interests: Competing interests: None declared., (© American Society of Regional Anesthesia & Pain Medicine 2024. No commercial re-use. See rights and permissions. Published by BMJ.)

Binding free energy calculations predict the potency of compounds to protein binding sites in a physically rigorous manner and see broad application in prioritizing the synthesis of novel drug candidates. Relative binding free energy (RBFE) calculations have emerged as an industry-standard approach to achieve highly accurate rank-order predictions of the potency of related compounds; however, this approach requires that the ligands share a common scaffold and a common binding mode, restricting the methods' domain of applicability. This is a critical limitation since complex modifications to the ligands, especially core hopping, are very common in drug design. Absolute binding free energy (ABFE) calculations are an alternate method that can be used for ligands that are not congeneric. However, ABFE suffers from a known problem of long convergence times due to the need to sample additional degrees of freedom within each system, such as sampling rearrangements necessary to open and close the binding site. Here, we report on an alternative method for RBFE, called Separated Topologies (SepTop), which overcomes the issues in both of the aforementioned methods by enabling large scaffold changes between ligands with a convergence time comparable to traditional RBFE. Instead of only mutating atoms that vary between two ligands, this approach performs two absolute free energy calculations at the same time in opposite directions, one for each ligand. Defining the two ligands independently allows the comparison of the binding of diverse ligands without the artificial constraints of identical poses or a suitable atom-atom mapping. This approach also avoids the need to sample the unbound state of the protein, making it more efficient than absolute binding free energy calculations. Here, we introduce an implementation of SepTop. We developed a general and efficient protocol for running SepTop, and we demonstrated the method on four diverse, pharmaceutically relevant systems. We report the performance of the method, as well as our practical insights into the strengths, weaknesses, and challenges of applying this method in an industrial drug design setting. We find that the accuracy of the approach is sufficiently high to rank order ligands with an accuracy comparable to traditional RBFE calculations while maintaining the additional flexibility of SepTop.

Whether the fascia iliaca compartment block (FICB) involves the obturator nerve (ON) remains controversial. Involvement may require that the injectate spreads deep in the cranial direction, and might thus depend on the site of injection. Therefore, the effect of suprainguinal needle insertion with five centimeters of hydrodissection-mediated needle advancement (S-FICB-H) on ON involvement and cranial injectate spread was studied in this radiological cadaveric study. Results were compared with suprainguinal FICB without additional hydrodissection-mediated needle advancement (S-FICB), infrainguinal FICB (I-FICB), and femoral nerve block (FNB). Seventeen human cadavers were randomized to receive ultrasound-guided nerve block with a 40 mL solution of local anesthetic and contrast medium, on both sides. Injectate spread was objectified using computed tomography. The femoral and lateral femoral cutaneous nerves were consistently covered when S-FICB-H, S-FICB or FNB was applied, while the ON was involved in only one of the 34 nerve blocks. I-FICB failed to provide the same consistency of nerve involvement as S-FICB-H, S-FICB or FNB. Injectate reached most cranial in specimens treated with S-FICB-H. Our results demonstrate that even the technique with the most extensive cranial spread (S-FICB-H) does not lead to ON involvement and as such, the ON seems unrelated to FICB. Separate ON block should be considered when clinically indicated., (© 2023. The Author(s).)

Water often plays a key role in mediating protein-ligand interactions. Understanding contributions from active-site water molecules to binding thermodynamics of a ligand is important in predicting binding free energies for ligand optimization. In this work, we tested a non-equilibrium switching method for absolute binding free energy calculations on water molecules in binding sites of 13 systems. We discuss the lessons we learned about identified issues that affected our calculations and ways to address them. This work fits with our larger focus on how to do accurate ligand binding free energy calculations when water rearrangements are very slow, such as rearrangements due to ligand modification (as in relative free energy calculations) or ligand binding (as in absolute free energy calculations). The method studied in this work can potentially be used to account for limited water sampling via providing endpoint corrections to free energy calculations using our calculated binding free energy of water.

Binding free energy calculations have become increasingly valuable to drive decision making in drug discovery projects. However, among other issues, inadequate sampling can reduce accuracy, limiting the value of the technique. In this paper, we apply absolute binding free energy calculations to ligands binding to T4 lysozyme L99A and HSP90 using equilibrium and nonequilibrium approaches. We highlight sampling problems encountered in these systems, such as slow side chain rearrangements and slow changes of water placement upon ligand binding. These same types of challenges are also likely to show up in other protein-ligand systems, and we propose some strategies to diagnose and test for such problems in alchemical free energy calculations. We also explore similarities and differences in how the equilibrium and the nonequilibrium approaches handle these problems. Our results show the large amount of work still to be done to make free energy calculations robust and reliable and provide insight for future research in this area.

Introduction: In the Emergency Department, regional anesthesia is increasingly used in elderly patients with hip fractures. An example is a Fascia Iliaca Compartment Block (FICB). Traditionally, this block is administered below the inguinal ligament. There is no Emergency Department data regarding effectivity of an alternative, more cranial approach above the inguinal ligament. The objective was to determine analgesic effects of an ultrasound-guided supra-inguinal FICB in hip fracture patients in the Emergency Department., Methods: This case series included all Emergency Department hip fracture patients who were treated with a supra-inguinal FICB during a period of 10 months. All data were recorded prospectively. Primary study outcome was decrease in Numerical Rating Scale (NRS) pain scores 60 min after the FICB. Secondary outcomes included the proportion of patients achieving 1.5 NRS points decrease at 60 min; NRS differences at 30 and 120 min compared to baseline; need for additional analgesia and occurrence of adverse events., Results: A total of 22 patients were included in the study. At 60 min median NRS pain scores decreased from 6.0 to 3.0 (p < 0.001). Of all patients, a total of 59% achieved a decrease in 1.5 NRS points after 60 min. Median pain scores at 30 and 120 min were 4.0 (Interquartile Range (IQR) 2.0-5.0) and 2.5 (IQR 0.8-3.0). Seven patients (31.8%) required additional opioid analgesia after the FICB. No adverse events were recorded., Conclusion: An ultrasound-guided supra-inguinal FICB decreases NRS pain scores in hip fracture patients both clinically relevant and statistically significantly after 60 min., Clinical Trial Registration: The study was registered in the ISRCTN database (ISRCTN74920258)., (Copyright © 2019 Elsevier Inc. All rights reserved.)

This integrative conceptual review is based on a critical need in the area of performance management (PM), where there remain important unanswered questions about the effectiveness of PM that affect both research and practice. In response, we create a theoretically grounded, comprehensive, and integrative model for understanding and measuring PM effectiveness, comprising multiple categories of evaluative criteria and the underlying mechanisms that link them. We then review more than 30 years (1984-2018) of empirical PM research vis-à-vis this model, leading to conclusions about what the literature has studied and what we do and do not know about PM effectiveness as a result. The final section of this article further elucidates the key "value chains" or mediational paths that explain how and why PM can add value to organizations, framed around three pressing questions with both theoretical and practical importance (How do individual-level outcomes of PM emerge to become unit-level outcomes? How essential are positive reactions to the overall effectiveness of PM? and What is the value of a performance rating?). This discussion culminates in specific propositions for future research and implications for practice. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Traumatic-induced coagulopathy (TIC) is a complex condition which develops both as a response to trauma as well as to clinical care interventions. Accurate and timely diagnostics are necessary to enable therapy aimed at correction of TIC. Viscoelastic hemostatic assays (VHA) are increasingly recognized for their potential to diagnose TIC as well as for guidance of treatment. This narrative review focuses on the evidence of the use of VHAs to diagnose TIC, to monitor efficacy of treatment of TIC during bleeding and to prognosticate outcome. Pitfalls of the use of VHA are also discussed., Competing Interests: Disclosure The authors report no conflicts of interest in this work., (Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.)

Background: Saphenous nerve block contributes to analgesia after knee and lower leg surgery. However, literature reports a wide range of volumes of local anesthetic being used for this block., Methods: A non-randomized controlled trial in a single university hospital in March 2015. Eighteen healthy volunteers (ASA 1 status, aged 27-43 years; male-to-female ratio 11/7) were needed to determine the minimum local anesthetic volume (MLAV) of mepivacaine 2% using the Dixon up-and-down method to achieve a selective ultrasound-guided saphenous nerve block. The primary endpoint MLAV (ED50 and ED95) for an ultrasound-guided saphenous nerve block were determined. The secondary endpoints were the position of the saphenous nerve, block onset and duration of action, cutaneous spread of the block, and the occurrence of femoral nerve motor block., Results: The measured MLAV dose that was effective in 50% of cases (ED50) for a complete saphenous nerve block was 1.5 mL; the calculated MLAV dose for 95% of cases (ED95) was 1.9 mL. The saphenous nerve was encountered in almost all cases on the anterior/anteromedial aspect of the femoral artery. We found no correlation between local anesthetic volume and the onset or duration of the block. Cutaneous spread of the nerve block was observed on the anteromedial aspect of the lower leg, with considerable individual variation between individuals in the study. No femoral motor block was observed., Conclusions: For a selective ultrasound-guided saphenous nerve block, the ED95 MLAV of mepivacaine 2% is 1.9 mL.

In this study, we examine the dynamics between emotional intelligence, work-family balance, and job performance. A review of the literature to date has shown distinct relationships between emotional intelligence to job performance and work-family balance to job performance. We utilize a sample of 233 respondents to empirically test our set of hypotheses that contend work-family balance mediates the relationship between emotional intelligence and job performance. Our results support these hypotheses. Practical implications and directions for future research are discussed.

Unlabelled: The reamer-irrigator-aspirator (RIA) is a device that has recently been developed to retrieve bone graft from the medullary canal of the femur and the tibia. As for most new surgical procedures, complications arise as part of the learning curve and/or imperfections in the design or technique. To increase awareness of potential complications and to prevent unnecessary harm to the patient, new complications need to be reported. We present case reports of 2 patients who developed severe intraoperative cardiac events presumably caused by excessive and rapid blood loss during RIA bone graft harvesting. This complication has not been described before. Increased awareness of excessive blood loss and subsequent cardiac events during an RIA procedure is warranted., Level of Evidence: Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Background: Massive transfusion protocols (MTPs) are increasingly used in the transfusion practice and are developed to provide the standardized and early delivery of blood products and procoagulant agents and to supply the transfusion of blood products in a well-balanced ratio., Aim: The aim of this study was to investigate the effect of a hospital-wide introduction of an MTP on blood product ratio and a waste of blood products., Materials and Methods: Retrospective analysis was performed to compare the transfusion practice in massive bleeding patients before and after the introduction of an MTP and between the use of an MTP and transfusion off-protocol. Massive bleeding was defined as an administration of ≥5 units of red blood cells (RBCs) within 12 h., Results: Of 547 massively transfused patients, 192 patients were included in the pre-MTP period and 355 patients in the MTP period. The ratio of RBC to fresh frozen plasma (FFP) and the platelets transfused shifted significantly toward 1:1:1 in the MTP period (P = 0.012). This was mainly caused by a shift in RBC: FFP ratio (P = 0.014). An increase in the waste of blood products was observed, most notably FFPs (P = 0.026). Extending the storage time after thawing reduced the waste of FFPs from 11% to 4%., Conclusion: Hospital-wide introduction of an MTP is an adequate way to achieve a well-balanced transfusion ratio of 1:1:1. This comes at the cost of an increase in the waste of FFPs, which is lowered after extending the duration of storage time after thawing.