Structural studies identify angiotensin II receptor blocker-like compounds as branched-chain ketoacid dehydrogenase kinase inhibitors.

The mammalian mitochondrial branched-chain ketoacid dehydrogenase (BCKD) complex is a multienzyme complex involved in the catabolism of branched-chain amino acids. BCKD is regulated by the BCKD kinase, or BCKDK, which binds to the E2 subunit of BCKD, phosphorylates its E1 subunit, and inhibits enzymatic activity. Inhibition of the BCKD complex results in increased levels of branched-chain amino acids and branched-chain ketoacids, and this buildup has been associated with heart failure, type 2 diabetes mellitus, and nonalcoholic fatty liver disease. To find BCKDK inhibitors for potential treatment of these diseases, we performed both NMR and virtual fragment screening and identified tetrazole-bearing fragments that bind BCKDK at multiple sites. Through structure-based virtual screening expanding from these fragments, the angiotensin receptor blocker class antihypertension drugs and angiotensin receptor blocker-like compounds were discovered to be potent BCKDK inhibitors, suggesting potential new avenues for heart failure treatment combining BCKDK inhibition and antihypertension.

Indian Perspective of Burnout Among Plastic Surgeons.

Introduction Over the last decade, the term "Burnout" has become familiar term in all walks of life, particularly medicine. Emotional exhaustion, depersonalization, and a low sense of personal accomplishment make up the triad. At least a third of plastic surgeons are having burnout according to the western literature. Data on burnout in Indian plastic surgeons is lacking. We have made an attempt to analyze the incidence and factors responsible for burnout among plastic surgeons in India. Materials and Methods An online survey was conducted in India to assess burnout among plastic surgeons from June to November 2019. Consent, demographic information, stress-related factors, the abbreviated Maslach Burnout Inventory (aMBI), and Satisfaction with Medicine were all included section wise in the survey. Both used scales were validated. Data were gathered using Google forms, then uploaded to an Excel file and analyzed. A multivariable and univariable analysis of factors associated with burnout was carried out. Results Twenty-two percent of 330 plastic surgeons who responded were assessed to have moderate to high emotional exhaustion, 5% had moderate to high depersonalization, and 3% had low personal accomplishment. The overall burnout rate was 8.2%. Seventy-three percent of plastic surgeons enjoyed a good to very good quality of life. Great over-volume of work, mid-career practicing plastic surgeons and professional satisfaction with work were found to have a significant association with burnout on multivariate analysis. Conclusions Plastic surgeons in India suffer an overall burnout rate of 8.2% with a multifactorial etiology. This occupational hazard is preventable and reversible. Plastic surgeons need to be vigilant about this and seek help whenever required.

Management of Posttraumatic Posterior Elbow Defects by Nonmicrosurgical Reconstruction.

Introduction Reconstruction of posterior defects is challenging due to the quality and uniqueness of the excess skin at the elbow that is durable, thick, pliable, and without much subcutaneous tissue. The goal of reconstruction is to cover the elbow defects with a durable skin cover that will facilitate full passive range of motion. In this era of microsurgery, free tissue transfer is feasible for almost any defect. However, in this article, we discuss various locoregional and pedicled flap options and the protocol followed at our institute to tackle posttraumatic posterior elbow defects. Materials and Methods This is a retrospective analysis of 48 patients with posttraumatic posterior elbow defects admitted from January 2012 to February 2020. Posterior elbow defects were assessed according to the size and location and managed with a nonmicrosurgical reconstruction. Results Of 48 patients, 32 were managed with nonmicrosurgical flaps. Eighteen patients had large defects and 14 had small defects. Reverse lateral forearm flap was the workhorse flap for defect coverage. Of 32 flaps, nine developed complications; however, no patient had total flap necrosis. Conclusion Posterior elbow defects are a difficult problem to tackle. To achieve optimal results, all patients with elbow trauma should be attended and managed by orthopaedic and plastic surgeons in collaboration for optimal results. We believe that most of these defects can be resurfaced by nonmicrosurgical reconstruction with proper planning and execution and their utility cannot be understated.

Toward the assembly and characterization of an encoded library hit confirmation platform: Bead-Assisted Ligand Isolation Mass Spectrometry (BALI-MS).

The ability to predict chemical structure from DNA sequence has to date been a necessary cornerstone of DNA-encoded library technology. DNA-encoded libraries (DELs) are typically screened by immobilized affinity selection and enriched library members are identified by counting the number of times an individual compound's sequence is observed in the resultant dataset. Those with high signal reads (DEL hits) are subsequently followed up through off-DNA synthesis of the predicted small molecule structures. However, hits followed-up in this manner often fail to translate to confirmed ligands. To address this low conversion rate of DEL hits to off-DNA ligands, we have developed an approach that eliminates the reliance on chemical structure prediction from DNA sequence. Here we describe our method of combining non-combinatorial resynthesis on-DNA following library procedures as a rapid means to assess the probable molecules attached to the DNA barcode. Furthermore, we apply our Bead-Assisted Ligand Isolation Mass Spectrometry (BALI-MS) technique to identify the true binders found within the mixtures of on-DNA synthesis products. Finally, we describe a Normalized Enrichment (NE) metric that allows for the quantitative assessment of affinity selection in these studies. We exemplify how this combined approach enables the identification of putative hit matter against a clinically relevant therapeutic target bisphosphoglycerate mutase, BPGM.

Nuances of Arteriovenous Fistula Creation for Vascular Access in Hemodialysis.

Background With rising incidence and increased life expectancy of patients with chronic kidney disease (CKD) and end-stage renal disease (ESRD), the number of patients requiring hemodialysis has increased substantially. Vascular access is the lifeline for a patient on hemodialysis (HD), and an arteriovenous fistula (AVF) is the undisputed gold standard for HD access. An effective and long-lasting fistula serves to increase the life expectancy of ESRD patients and improves their quality of life. Learning Objectives This paper aims to give a comprehensive overview of AVF creation, including the various techniques, patient selection, troubleshooting with decision-making, and common complications. Authors share their experience from previous publications and over 2000 AVF surgeries. They have not only described a new modification of the technique of proximal fistula but have also established a direct correlation between bruit and thrill on operation table and success of fistula surgery. Conclusion A standardized, protocol-driven multidisciplinary approach with careful patient and site selection, guided by outcome predictors, is vital in AVF surgery. Knowledge about the potential complications of AVFs contributes to their timely detection and allows measures to be taken that might prevent deleterious consequences that range from loss of vascular access to serious morbidity and mortality.

Post-CABG Deep Sternal Wound Infection: A Retrospective Comparative Analysis of Early versus Late Referral to a Plastic Surgery Unit in a Tertiary Care Center.

Background Deep sternal wound infections (DSWI) following median sternotomy are initially treated by the cardiothoracic surgeons and are referred to a plastic surgical unit late in the course of time. Methods This is a retrospective review done in a tertiary care teaching institute from January 2005 to June 2018 and the data of 72 patients who had DSWI out of 4,214 patients who underwent median sternotomy for coronary artery bypass grafting (CABG) was collected with respect to the duration between CABG and presentation of DSWI as well as time of referral to a plastic surgery unit. We defined early referral as < or equal to 15 days from presentation and late referral as > 15 days. Both groups were compared with respect to multiple parameters as well as early and late postoperative course, postoperative complications, and mortality. Results The early group had 33 patients, while the late group had 39 patients. The number of procedures done by the cardiothoracic team before referral to the plastic surgery unit is significant ( p = 0.002). The average duration from the presentation of DSWI to definitive surgery was found to be 16.58 days in the early group and 89.36 days in the late group. The rest of the variables that were compared in both the groups did not have significant differences. Conclusion There is no statistical difference between early and late referral to plastic surgery in terms of mortality and morbidity. Yet, early referrals could lead to highly significant reduction in total duration of hospital stay, wound healing, and costs. Early referral of post-CABG DSWIs to Plastic surgeons by the cardiothoracic surgeons is highly recommended.

Burnout among Plastic Surgery Residents in India: An Observational Study.

Introduction Burnout syndrome can be defined as emotional exhaustion, depersonalization, and perceived lack of personal accomplishment, all of which lead to decreased effectiveness at work. The Medscape burnout and depression report of 2018 suggests that the burnout range across various specialties ranges from 23 to 48%. There are no studies to assess the burnout among plastic surgery residents in India. This study is an attempt to assess the same. Materials and Methods An online survey was conducted in March and April 2019 for plastic surgery residents across India. Various parameters including those related to gender, year of the curriculum, hobbies, exercise, and marital status were assessed. There were multiple sections in the survey, which included the demographic details, stress-related variables, and the abbreviated Maslach Burnout Inventory. The abbreviated Maslach Burnout Inventory is a validated scale that has been used to assess the burnout among plastic surgery residents in India. The three subscales, emotional exhaustion, depersonalization, and personal accomplishment were measured on a Likert scale. Univariable and multivariable analysis of factors associated with burnout was performed. Results Of the 185 respondents, 48.4% experienced moderate-to-high burnout. Of these, 25% ( n = 46) were above the 75th centile of the overall burnout score, indicating severe burnout. Insufficient faculty involvement, insufficient time allotted for formalized teaching, conflict with colleagues, and lack of adequate support staff correlated with resident burnout on multivariate analysis. Residents who pursued their hobbies or performed physical activities for exercise had significantly lesser burnout. Conclusion The incidence of burnout in plastic surgery residents surveyed in our study was 48.4%. The faculty of the departments and the residents themselves, as well as the governing bodies, all have a role to play to address the issue of burnout among residents. Dedicated and persistent efforts toward improving physical and psychological well-being of plastic surgery residents will positively impact not only the well-being of the residents but also the quality of patient care.

Probing the enzyme kinetics, allosteric modulation and activation of α1- and α2-subunit-containing AMP-activated protein kinase (AMPK) heterotrimeric complexes by pharmacological and physiological activators.

AMP-activated protein kinase (AMPK) is a serine/threonine protein kinase that serves as a pleotropic regulator of whole body energy homoeostasis. AMPK exists as a heterotrimeric complex, composed of a catalytic subunit (α) and two regulatory subunits (ß and γ), each present as multiple isoforms. In the present study, we compared the enzyme kinetics and allosteric modulation of six recombinant AMPK isoforms, α1ß1γ1, α1ß2γ1, α1ß2γ3, α2ß1γ1, α2ß2γ1 and α2ß2γ3 using known activators, A769662 and AMP. The α1-containing complexes exhibited higher specific activities and lower Km values for a widely used peptide substrate (SAMS) compared with α2-complexes. Surface plasmon resonance (SPR)-based direct binding measurements revealed biphasic binding modes with two distinct equilibrium binding constants for AMP, ADP and ATP across all isoforms tested. The α2-complexes were ∼25-fold more sensitive than α1-complexes to dephosphorylation of a critical threonine on their activation loop (pThr(172/174)). However, α2-complexes were more readily activated by AMP than α1-complexes. Compared with ß1-containing heterotrimers, ß2-containing AMPK isoforms are less sensitive to activation by A769662, a synthetic activator. These data demonstrate that ligand induced activation of AMPK isoforms may vary significantly based on their AMPK subunit composition. Our studies provide insights for the design of isoform-selective AMPK activators for the treatment of metabolic diseases.

Free style perforator based propeller flaps: Simple solutions for upper extremity reconstruction!

BACKGROUND: The introduction of perforator flaps by Koshima et al. was met with much animosity in the plastic surgery fraternity. The safety concerns of these flaps following the intentional twist of the perforators have prevented widespread adoption of this technique. Use of perforator based propeller flaps in the lower extremity is gradually on the rise, but their use in upper extremity reconstruction is infrequently reported, especially in the Indian subcontinent. MATERIALS AND METHODS: We present a retrospective series of 63 free style perforator flaps used for soft tissue reconstruction of the upper extremity from November 2008 to June 2013. Flaps were performed by a single surgeon for various locations and indications over the upper extremity. Patient demographics, surgical indication, defect features, complications and clinical outcome are evaluated and presented as an uncontrolled case series. RESULTS: 63 free style perforator based propeller flaps were used for soft tissue reconstruction of 62 patients for the upper extremity from November 2008 to June 2013. Of the 63 flaps, 31 flaps were performed for trauma, 30 for post burn sequel, and two for post snake bite defects. We encountered flap necrosis in 8 flaps, of which there was complete necrosis in 4 flaps, and partial necrosis in four flaps. Of these 8 flaps, 7 needed a secondary procedure, and one healed secondarily. Although we had a failure rate of 12-13%, most of our failures were in the early part of the series indicative of a learning curve associated with the flap. CONCLUSION: Free style perforator based propeller flaps are a reliable option for coverage of small to moderate sized defects. LEVEL OF EVIDENCE: Therapeutic IV.

Prospective long-term study of patency and outcomes of 505 arteriovenous fistulas in patients with chronic renal failure: Authors experience and review of literature.

BACKGROUND: This study describes our experience of arteriovenous fistula (AVF) creation as vascular access for haemodialysis. MATERIALS AND METHODS: This study has been carried out in our hospital from January 2004 to December 2012. A total of 505 AVFs were created in 443 patients. Maximum follow-up was 8 years, and minimum was 6 months. OBSERVATIONS AND RESULTS: In this study of 505 cases of AVFs, primary patency rates by Kaplan - Meier analysis showed 78.81% patency of fistulas at the end of 1 year and patency dropped to 14.81% at the end of 5 years. Our primary failure rate was 21.2%. Basilic vein was used in 26.35% cases, cephalic vein in 63.5%, and antecubital vein in 9.75% cases. On table, bruit was present in 459 (90.9%) and thrill in 451 (89.3%) cases. During dialysis, flow rate >250 ml/min was obtained in 150 (29.9%) cases. In complications, 2 (0.4%) patients developed distal oedema, 33 (6.5%) developed steal phenomenon. CONCLUSIONS: Presence of on table thrill and bruit are indicators of successful AVF. If vein diameter is <2 mm, chances of AVF failure are high. Flow rates in patients with vein diam. >2 mm were significantly higher as compared with patients with vein diam. <2 mm (P < 0.001). Flow rates are higher in non-diabetic patients as compared to diabetic patients (P < 0.001). Average blood urea and serum creatinine values are significantly lesser in patients undergoing dialysis through successful fistulas as compared to patients with failed fistulas. Correspondingly, incidence of deaths is significantly lesser in patients with successful fistulas. During proximal side-to-side fistula between antecubital/basilic vein and brachial artery, dilating of the first valve toward wrist helps to develop distal veins in the forearm by retrograde flow. This technique avoids requirement of superficialization of basilic vein in the arm.

Small molecule branched-chain ketoacid dehydrogenase kinase (BDK) inhibitors with opposing effects on BDK protein levels.

Branched chain amino acid (BCAA) catabolic impairments have been implicated in several diseases. Branched chain ketoacid dehydrogenase (BCKDH) controls the rate limiting step in BCAA degradation, the activity of which is inhibited by BCKDH kinase (BDK)-mediated phosphorylation. Screening efforts to discover BDK inhibitors led to identification of thiophene PF-07208254, which improved cardiometabolic endpoints in mice. Structure-activity relationship studies led to identification of a thiazole series of BDK inhibitors; however, these inhibitors did not improve metabolism in mice upon chronic administration. While the thiophenes demonstrated sustained branched chain ketoacid (BCKA) lowering and reduced BDK protein levels, the thiazoles increased BCKAs and BDK protein levels. Thiazoles increased BDK proximity to BCKDH-E2, whereas thiophenes reduced BDK proximity to BCKDH-E2, which may promote BDK degradation. Thus, we describe two BDK inhibitor series that possess differing attributes regarding BDK degradation or stabilization and provide a mechanistic understanding of the desirable features of an effective BDK inhibitor.

Discovery of High-Affinity Small-Molecule Binders of the Epigenetic Reader YEATS4.

A series of small-molecule YEATS4 binders have been discovered as part of an ongoing research effort to generate high-quality probe molecules for emerging and/or challenging epigenetic targets. Analogues such as 4d and 4e demonstrate excellent potency and selectivity for YEATS4 binding versus YEATS1,2,3 and exhibit good physical properties and in vitro safety profiles. A new X-ray crystal structure confirms direct binding of this chemical series to YEATS4 at the lysine acetylation recognition site of the YEATS domain. Multiple analogues engage YEATS4 with nanomolar potency in a whole-cell nanoluciferase bioluminescent resonance energy transfer assay. Rodent pharmacokinetic studies demonstrate the competency of several analogues as in vivo-capable binders.

PF-07059013: A Noncovalent Modulator of Hemoglobin for Treatment of Sickle Cell Disease.

Sickle cell disease (SCD) is a genetic disorder caused by a single point mutation (ß6 Glu → Val) on the ß-chain of adult hemoglobin (HbA) that results in sickled hemoglobin (HbS). In the deoxygenated state, polymerization of HbS leads to sickling of red blood cells (RBC). Several downstream consequences of polymerization and RBC sickling include vaso-occlusion, hemolytic anemia, and stroke. We report the design of a noncovalent modulator of HbS, clinical candidate PF-07059013 (23). The seminal hit molecule was discovered by virtual screening and confirmed through a series of biochemical and biophysical studies. After a significant optimization effort, we arrived at 23, a compound that specifically binds to Hb with nanomolar affinity and displays strong partitioning into RBCs. In a 2-week multiple dose study using Townes SCD mice, 23 showed a 37.8% (±9.0%) reduction in sickling compared to vehicle treated mice. 23 (PF-07059013) has advanced to phase 1 clinical trials.

The Reach of the Gastrocnemius Musculocutaneous Flap: How High Is High?

BACKGROUND: Gastrocnemius muscle and musculocutaneous flaps are very versatile and one of the commonly used flaps for lower extremity reconstruction. There is significant literature available on the use of these flaps. However, we feel that the potential of the gastrocnemius musculocutaneous (GMC) flaps has not yet been fully explored in terms of increasing their reach, viability and arc of rotation. An attempt is made to refine the technique of flap harvestation to optimize outcomes of this versatile flap. METHODS: Six patients of complex lower limb defects were managed using the GMC flaps. Harvesting of the flap was always initiated from the posterior midline to include the proximal sural pedicle, sural nerve, short saphenous vein and the muscle belly of either the medial or the lateral gastrocnemius muscle along with the cutaneous paddle. All the flaps were islanded and denervated. The origin of the gastrocnemius muscle was detached in all cases to increase the reach of this flap. RESULTS: The flap can reliably and comfortably cover defects from middle third-lower third junction of thigh and the entire posterior aspect of the thigh. Such a local option offers relatively simple but more cost-effective approach to complex clinical problem with tolerable impairment of the donor site. CONCLUSION: The GMC flap can be considered as a worthwhile alternative to free-tissue transfer for limb salvage.

The Anterior Interosseus Artery Perforator Flap: Anatomical Dissections and Clinical Study.

BACKGROUND: Reconstruction of upper extremity deformities continues to be a challenge to the reconstructive surgeon. Various loco regional, distant and free flaps are available for reconstruction. However, each has its own set of advantages and disadvantages. Of the commonly performed local flaps, radial artery forearm flap, and the posterior interosseus artery flap stand out prominently. Recently, perforator propeller flaps have been used for resurfacing the upper extremity. The anterior interosseus artery perforator flap is an uncommonly used and described flap. METHODS: This study was divided into anatomical study and clinical application in a IV level of evidence. In the anatomical study, five upper extremities were studied. Clinically, 12 patients underwent reconstruction using the anterior interosseus artery perforator flap. Flaps were performed by a single surgeon. A retrospective review of these cases from November 2008 to May 2014 is presented. RESULTS: The anterior interosseus artery perforator was identified in four out of five cadaver limbs. The septocutaneous perforator was in the fifth extensor compartment around 4 cm proximal to the wrist joint. Of the twelve flaps, there was complete necrosis in one flap, and partial necrosis in one flap. The patient with complete necrosis underwent skin grafting at a later date. The wound healed secondarily in case of partial flap necrosis. CONCLUSION: Anterior interosseus artery perforator flap must be considered as an important reconstructive option in the armamentarium of the plastic surgeon, while managing hand and wrist defects.

Structure-Based Design of Highly Selective Inhibitors of the CREB Binding Protein Bromodomain.

Chemical probes are required for preclinical target validation to interrogate novel biological targets and pathways. Selective inhibitors of the CREB binding protein (CREBBP)/EP300 bromodomains are required to facilitate the elucidation of biology associated with these important epigenetic targets. Medicinal chemistry optimization that paid particular attention to physiochemical properties delivered chemical probes with desirable potency, selectivity, and permeability attributes. An important feature of the optimization process was the successful application of rational structure-based drug design to address bromodomain selectivity issues (particularly against the structurally related BRD4 protein).