Impact of Regional Differences and Neighborhood Socioeconomic Deprivation on the Outcomes of Patients with Lower Extremity Wounds Evaluated by a Limb-Preservation Service.

INTRODUCTION: Management of lower extremity (LE) wounds has evolved with the establishment of specialized limb preservation services. While clinical factors contribute to limb outcomes, socioeconomic status and community factors also influence the risk for limb loss. The Distressed Community Index (DCI) score is a validated index of social deprivation created to provide an objective measure of economic well-being in U.S communities. Few studies have examined the influence of geographic deprivation on outcomes in patients with LE wounds. We examined relationships between socioeconomic deprivation and outcomes of inpatients evaluated by a dedicated limb preservation service (FLEX). METHODS: Inpatients referred to FLEX over a 5-year period were included. Wound, Ischemia, foot Infection (WIfI) staging was collected. DCI scores were determined using 7 indices based on ZIP Code. Outcomes included any minor or major amputations, any endovascular or open LE revascularization, or wound care procedures. Disease etiology, demographic, and anthropometric data were collected. Associations between neighborhood deprivation and limb-specific outcomes were evaluated in models for the DCI and each of its components separately. RESULTS: 677 patients were included. Thirty-eight percent were female, with a mean age of 64 years. Sixty percent had WIfI stage 3 or 4 risk of amputation, and 43% had WIfI stage 3 or 4 risk of revascularization. Mean (SD) ABI and toe pressure were 0.96 (0.43) and 80 (57) mmhg. Thirty-five percent were non-white. Amputation was performed in 31% of patients while 17% underwent revascularization. The mean (SD) distress score was 64 (24). Mean DCI scores did not differ across WIfI scores. Likewise, overall DCI distress score was not related to any of the outcomes in univariable or multivariable LR models. In univariable LR models for amputation, higher poverty rate (odds ratio (OR) for SD increase 1.20, 95% confidence limits (CL) 1.02-1.42, P=0.025) was significantly associated with the outcome. In multivariable models, neither DCI distress score nor any of its components remained significantly associated with the outcome. CONCLUSIONS: Despite known racial disparities in limb-specific outcomes, an aggregate measure of community level distress was not found to be related to outcomes. While poverty rate demonstrated a significant relationship with amputation in univariable analysis, this association was not found in multivariable models. Notably, non-white race emerged as a predictor of amputation, underscoring the importance of addressing racial disparities in LE outcomes. Further investigation of potential determinants of LE outcomes is needed, particularly the interaction of such factors with race.

Computational Design of Cyclic Peptide Inhibitors of a Bacterial Membrane Lipoprotein Peptidase.

There remains a critical need for new antibiotics against multi-drug-resistant Gram-negative bacteria, a major global threat that continues to impact mortality rates. Lipoprotein signal peptidase II is an essential enzyme in the lipoprotein biosynthetic pathway of Gram-negative bacteria, making it an attractive target for antibacterial drug discovery. Although natural inhibitors of LspA have been identified, such as the cyclic depsipeptide globomycin, poor stability and production difficulties limit their use in a clinical setting. We harness computational design to generate stable de novo cyclic peptide analogues of globomycin. Only 12 peptides needed to be synthesized and tested to yield potent inhibitors, avoiding costly preparation of large libraries and screening campaigns. The most potent analogues showed comparable or better antimicrobial activity than globomycin in microdilution assays against ESKAPE-E pathogens. This work highlights computational design as a general strategy to combat antibiotic resistance.

Impact of pre- and peri-operative risk factors on length of stay and hospital readmission following minimally-invasive partial nephrectomy.

Objective: We conducted an analysis of the American College of Surgeons National Surgical Quality Improvement Program database for minimally-invasive partial nephrectomy cases reported with the goal to identify pre- and peri-operative variables associated with length of stay (LOS) greater than 3 days and readmission within 30 days. Methods: Records from 2008 to 2018 for "laparoscopy, surgical; partial nephrectomy" for prolonged LOS and readmission cohorts were compiled. Univariate analysis with Chi-square, t-tests, and multivariable logistic regression analysis with odds ratios (ORs), p-values, and 95% confidence intervals assessed statistical associations. Results: Totally, 20 306 records for LOS greater than 3 days and 15 854 for readmission within 30 days were available. Univariate and multivariable analysis exhibited similar results. For LOS greater than 3 days, undergoing non-elective surgery (OR=5.247), transfusion of greater than four units within 72 h prior to surgery (OR=5.072), pre-operative renal failure or dialysis (OR=2.941), and poor pre-operative functional status (OR=2.540) exhibited the strongest statistically significant associations. For hospital readmission within 30 days, loss in body weight greater than 10% in 6 months prior to surgery (OR=2.227) and bleeding disorders (OR=2.081) exhibited strongest statistically significant associations. Conclusion: Multiple pre- and peri-operative risk factors are independently associated with prolonged LOS and hospital readmission within 30 days of surgery using the American College of Surgeons National Surgical Quality Improvement Program data. Recognizing the risks factors that can potentially be improved prior to minimally-invasive partial nephrectomy is crucial to informing patient selection, optimization strategies, and patient education.

A meta-analysis of the performance of ultrasound, hepatobiliary scintigraphy, CT and MRI in the diagnosis of acute cholecystitis.

PURPOSE: To evaluate the recently reported relative diagnostic accuracy of US, CT, MRI, and cholescintigraphy for diagnosing acute cholecystitis. METHODS: 2 radiologists independently performed systematic electronic searches for articles published between 2000 and 2021 and applied inclusion/exclusion criteria. 2 different radiologists extracted data from the articles and scored each with a methodological quality tool. Pooled estimates of sensitivity and specificity were calculated with a bivariate linear mixed model. A second analysis made head-to-head comparisons (US vs. CT, US vs. cholescintigraphy). Factors were also analyzed for potential confounding effects on diagnostic accuracy. RESULTS: Of 6121 initial titles, 22 were included. The prevalence of cholecystitis varied widely across studies (9.4-98%). Pooled sensitivity and specificity estimates were 69% (confidence limit [CL] 62-76%) and 79% (CL 71-86%) for US, 91% (CL 86-94%) and 63% (CL 51-74%) for cholescintigraphy, 78% (CL 69-84%) and 81% (CL 71-88%) for CT, and 91% (CL 78-97%) and 93% (CL 70-99%) for MRI. Regarding head-to-head comparisons, the sensitivity of CT (87.6%, CL 70-96%) was significantly higher than US (66.8%, CL 43-84%), while specificities (81.7% with CL 54-95% for US, 91.9% with CL 67-99% for CT) were similar. The sensitivity of cholescintigraphy (87.4%, CL 76-94%) was significantly greater than US (61.6%, CL 44-77%), while the specificity of US (82%, CL 65-92%) was significantly higher than cholescintigraphy (68%, CL 47-84%). CONCLUSION: Recent data suggests that CT may have a higher sensitivity than US for diagnosing acute cholecystitis, with similar specificity. Cholescintigraphy remains a highly sensitive modality with lower specificity than previously reported. MRI remains under studied, but with promising results.

Neuropathy Screening for Patients with Peripheral Vascular Disease Helps to Identify Those at an Increased Risk of Amputation, Revascularization, and Death.

BACKGROUND: Peripheral neuropathy is associated with amputation risk among patients with diabetes mellitus and chronic limb-threatening ischemia (CLTI). Detection of peripheral neuropathy may help identify those who are at an increased risk, but the predictive ability of the screening tool used in patients with peripheral arterial disease (PAD) needs to be more clearly defined. METHODS: Patients referred to vascular surgery clinic for PAD were recruited from a single center. Exclusion criteria were a documented history of neuropathy or prior lower limb amputation. Screening utilized the Michigan Neuropathy Screening Instrument (MNSI). Scores >2.5 were considered abnormal and scores >4 were considered positive for peripheral neuropathy. Limb-specific outcomes of amputation and revascularization as well as a composite outcome including death were modeled using time to event analysis. RESULTS: 86 patients were recruited. Mean age was 67 ± 10.2 years, 30% were women, 24% were black. Mean ankle-brachial index was 0.74 ± 0.3. PAD symptoms at initial evaluation were claudication in 52% of patients and CLTI in 38% of patients. Neuropathy was present in 20% of the cohort with a significantly higher proportion in diabetics (34% vs. 3%; P = 0.0009). Neuropathy was more common in patients with CLTI compared to claudicants (36% vs. 9%; P = 0.011). Forty patients (47%) reached the composite outcome of amputation, revascularization, or death with a median time to event of 16 months. Abnormal MNSI examination was significantly associated with the increased risk of the composite outcome (hazard ratio = 3.19; P 0.0005). CONCLUSIONS: A significant proportion of patients presenting to vascular specialists for PAD have undiagnosed neuropathy. Patients with PAD and neuropathy have an increased risk of amputation, revascularization, and death. Expanding neuropathy screening in vascular surgery clinic visits may help to identify patients at higher risk.

Design and structural validation of peptide-drug conjugate ligands of the kappa-opioid receptor.

Despite the increasing number of GPCR structures and recent advances in peptide design, the development of efficient technologies allowing rational design of high-affinity peptide ligands for single GPCRs remains an unmet challenge. Here, we develop a computational approach for designing conjugates of lariat-shaped macrocyclized peptides and a small molecule opioid ligand. We demonstrate its feasibility by discovering chemical scaffolds for the kappa-opioid receptor (KOR) with desired pharmacological activities. The designed De Novo Cyclic Peptide (DNCP)-ß-naloxamine (NalA) exhibit in vitro potent mixed KOR agonism/mu-opioid receptor (MOR) antagonism, nanomolar binding affinity, selectivity, and efficacy bias at KOR. Proof-of-concept in vivo efficacy studies demonstrate that DNCP-ß-NalA(1) induces a potent KOR-mediated antinociception in male mice. The high-resolution cryo-EM structure (2.6 Å) of the DNCP-ß-NalA-KOR-Gi1 complex and molecular dynamics simulations are harnessed to validate the computational design model. This reveals a network of residues in ECL2/3 and TM6/7 controlling the intrinsic efficacy of KOR. In general, our computational de novo platform overcomes extensive lead optimization encountered in ultra-large library docking and virtual small molecule screening campaigns and offers innovation for GPCR ligand discovery. This may drive the development of next-generation therapeutics for medical applications such as pain conditions.

Contemporary outcomes for branch renal artery repair.

BACKGROUND: The purpose of this study was to provide an updated description of demographics, technical details, and clinical outcomes of 101 consecutive branch renal artery repairs in 98 patients using cold perfusion. METHODS: A single-institution, retrospective analysis branch renal artery reconstructions was performed between 1987 and 2019. RESULTS: Patients were predominantly Caucasian (80.6%) women (74.5%) with a mean age of 46.8 ± 15.3 years. The mean preoperative systolic and diastolic blood pressures were 170.4 ± 33.0 mm Hg and 99.2 ± 19.9 mm Hg, respectively, requiring a mean of 1.6 ± 1.1 antihypertensive medications. The estimated glomerular filtration rate was 84.0 ± 25.3 mL/min. Most patients (90.2%) were not diabetic and never smokers (68%). Treated pathology included aneurysm (87.4%) and stenosis (23.3%) with histology demonstrating fibromuscular dysplasia (44.4%), dissection (5.1%), and degenerative not otherwise specified (50.5%). The right renal arteries were most frequently treated (44.2%), with a mean of 3.1 ± 1.5 branches involved. Reconstruction was accomplished using bypass in 90.3% of cases using aortic inflow in 92.7% and a saphenous vein conduit in 92%. Branch vessels served as outflow in 96.9% and syndactylization of branches was used to decrease the number of distal anastomoses in 45.3% of repairs. The mean number of distal anastomoses was 1.5 ± 0.9. Postoperatively, the mean systolic blood pressure improved to 137.9 ± 20.8 mm Hg (mean decrease of 30.5 ± 32.8 mm Hg; P < .0001) and the mean diastolic blood pressure improved to 78.4 ± 12.7 mm Hg (mean decrease of 20.1 ± 20.7 mm Hg; P < .0001) with patients requiring a mean of 1.4 ± 1.0 antihypertensive medications (mean decrease of 0.2 ±1.0 medications; P = .048). The postoperative estimated glomerular filtration rate was 89.1 mL/min (mean increase of 4.1 mL/min; P = .08). The mean length of stay was 9.0 ± 5.8 days and 96.1% of patients were discharged home. The mortality rate was 1% (one patient with liver failure) and the major morbidity rate was 15%. There were five infectious complications (pneumonia, Clostridium difficile, and wound infection) and five patients required return to the operating room (one for nephrectomy, one for bleeding, two for thrombosis, and one for second trimester pregnancy loss requiring dilation and curettage and splenectomy). One patient required temporary dialysis owing to graft thrombosis. Two patients developed arrhythmias. No patients suffered a myocardial infarction, stroke, or limb loss. After 30 days, follow-up data were available for 82 bypasses. At this time, three reconstructions were no longer patent. Intervention was required to retain patency for five bypasses. After 1 year, patency data were available for 61 bypasses and five were no longer patent. Of the five grafts with loss of patency, two underwent intervention in attempt to maintain patency, which subsequently failed. CONCLUSIONS: Repair of renal artery pathology involving the branches can be performed with short- and long-term technical success and significant prospect of decreasing an elevated blood pressure. The operations required to fully address the presenting pathology are often quite complex involving multiple distal anastomoses and consolidation of small secondary branches. The procedure carries a small but significant risk of major morbidity and mortality.

Predicting short-term adverse outcomes in the geriatric population presenting with syncope: a comparison of existing syncope rules and beyond.

OBJECTIVES: Syncope at age 65+ is associated with increased mortality, irrespective of cause. Syncope rules were designed to aid in risk-stratification but were only validated in the general adult population. Our objective was to determine if they can be applied to a geriatric population in predicting short-term adverse outcomes. METHODS: In this single-center retrospective study, we evaluated 350 patients aged 65+ presenting with syncope. Exclusion criteria included confirmed non-syncope, active medical condition, drug or alcohol-related syncope. Patients were stratified into high or low risk based on Canadian Syncope Risk Score (CSRS), Evaluation of Guidelines in Syncope Study (EGSYS), San Francisco Syncope Rule (SFSR), and Risk Stratification of Syncope in the Emergency Department (ROSE). Composite adverse outcomes at 48-hour and 30-day included all-cause mortality, major adverse cardiac and cerebrovascular events (MACCE), return emergency department visit, hospitalization, or medical intervention. We assessed each score's ability to predict the outcomes using logistic-regression and compared performances using receiver-operator curves. Multivariate analyses were performed to study the associations between recorded parameters and outcomes. RESULTS: CSRS outperformed with AUC of 0.732 (95% CI: 0.653-0.812) and 0.749 (95% CI: 0.688-0.809) for 48-h and 30-day outcomes, respectively. Sensitivities for CSRS, EGSYS, SFSR, and ROSE for 48-hour outcomes were 48%, 65%, 42% and 19%; and for 30-day outcomes were 72%, 65%, 30% and 55%, respectively. Atrial fibrillation/flutter on EKG, congestive heart failure, antiarrhythmics, systolic blood-pressure < 90 at triage, and associated chest pain highly correlated with 48-h outcomes. An EKG abnormality, heart disease history, severe pulmonary hypertension, BNP > 300, vasovagal predisposition, and antidepressants highly correlated with 30-day outcomes. CONCLUSIONS: Performance and accuracy of four prominent syncope rules were suboptimal in identifying high-risk geriatric patients with short-term adverse outcomes. We identified some significant clinical and laboratory information that may play a role in predicting short-term adverse events in a geriatric cohort.

Cyclic Peptide Screening Methods for Preclinical Drug Discovery.

Cyclic peptides are among the most diverse architectures for current drug discovery efforts. Their size, stability, and ease of synthesis provide attractive scaffolds to engage and modulate some of the most challenging targets, including protein-protein interactions and those considered to be "undruggable". With a variety of sophisticated screening technologies to produce libraries of cyclic peptides, including phage display, mRNA display, split intein circular ligation of peptides, and in silico screening, a new era of cyclic peptide drug discovery is at the forefront of modern medicine. In this perspective, we begin by discussing cyclic peptides approved for clinical use in the past two decades. Particular focus is placed around synthetic chemistries to generate de novo libraries of cyclic peptides and novel methods to screen them. The perspective culminates with future prospects for generating cyclic peptides as viable therapeutic options and discusses the advantages and disadvantages currently being faced with bringing them to market.

Accurate de novo design of membrane-traversing macrocycles.

We use computational design coupled with experimental characterization to systematically investigate the design principles for macrocycle membrane permeability and oral bioavailability. We designed 184 6-12 residue macrocycles with a wide range of predicted structures containing noncanonical backbone modifications and experimentally determined structures of 35; 29 are very close to the computational models. With such control, we show that membrane permeability can be systematically achieved by ensuring all amide (NH) groups are engaged in internal hydrogen bonding interactions. 84 designs over the 6-12 residue size range cross membranes with an apparent permeability greater than 1 × 10-6 cm/s. Designs with exposed NH groups can be made membrane permeable through the design of an alternative isoenergetic fully hydrogen-bonded state favored in the lipid membrane. The ability to robustly design membrane-permeable and orally bioavailable peptides with high structural accuracy should contribute to the next generation of designed macrocycle therapeutics.

Generation of Potent and Stable GLP-1 Analogues Via "Serine Ligation".

Peptide and protein bioconjugation technologies have revolutionized our ability to site-specifically or chemoselectively install a variety of functional groups for applications in chemical biology and medicine, including the enhancement of bioavailability. Here, we introduce a site-specific bioconjugation strategy inspired by chemical ligation at serine that relies on a noncanonical amino acid containing a 1-amino-2-hydroxy functional group and a salicylaldehyde ester. More specifically, we harness this technology to generate analogues of glucagon-like peptide-1 that resemble Semaglutide, a long-lasting blockbuster drug currently used in the clinic to regulate glucose levels in the blood. We identify peptides that are more potent than unmodified peptide and equipotent to Semaglutide in a cell-based activation assay, improve the stability in human serum, and increase glucose disposal efficiency in vivo. This approach demonstrates the potential of "serine ligation" for various applications in chemical biology, with a particular focus on generating stabilized peptide therapeutics.

The imaging diagnosis of cholecystitis in the adult ED: a comparative multi-reader, multivariable analysis of CT and US image features.

PURPOSE: The purposes of this study are (1) to utilize multivariable logistic regression in order to evaluate which image feature combination is most predictive in the diagnosis of cholecystitis for computed tomography (CT) and ultrasound (US) in adult ED patients and (2) to use these results to compare the accuracy of CT and US. METHODS: For RUQ pain patients undergoing US and CT at the same visit, multiple image features were evaluated independently by 2 radiologists blinded to additional data. Inter-reader variability was measured with the Kappa statistic. Sonographic Murphy's sign (SMS) information was obtained from original reports. Multivariable logistic regression was utilized to develop optimal predictive models for each modality. For US, models with/without SMS were compared to establish its relative value. RESULTS: 446 patients met inclusion criteria. For CT, the combination of cholelithiasis, short-axis gallbladder diameter > 3 cm, pericholecystic fluid or inflammation, and mural thickening > 3 mm provided the optimal model for both readers. For US, the optimal model included cholelithiasis, short-axis diameter > 3 cm, mural heterogeneity/striation, and sludge/debris for both readers. Kappa = 0.79-0.96 for included image features. For both readers, CT and US models had equivalent diagnostic performances; the SMS did not contribute significantly to US models. CONCLUSION: For a diagnosis of cholecystitis in the ED, (1) the optimal image feature combination for CT is cholelithiasis, short-axis diameter > 3 cm, pericholecystic fluid or inflammation, mural thickening > 3 mm; and cholelithiasis, short-axis diameter > 3 cm, mural heterogeneity/striation, sludge/debris for US; (2) CT and US have equivalent diagnostic performance; (3) inter-reader reliability is substantial to excellent for utilized image features; (4) the SMS does not affect US model accuracy.

Association between secondhand marijuana smoke and respiratory infections in children.

BACKGROUND: Little is known about the effects of secondhand marijuana smoke on children. We aimed to determine caregiver marijuana use prevalence and evaluate any association between secondhand marijuana smoke, childhood emergency department (ED) or urgent care (UC) visitation, and several tobacco-related illnesses: otitis media, viral respiratory infections (VRIs), and asthma exacerbations. METHODS: This study was a cross-sectional, convenience sample survey of 1500 subjects presenting to a pediatric ED. The inclusion criteria were as follows: caregivers aged 21-85 years, English- or Spanish-speaking. The exclusion criteria were as follows: children who were critically ill, medically complex, over 11 years old, or using medical marijuana. RESULTS: Of 1500 caregivers, 158 (10.5%) reported smoking marijuana and 294 (19.6%) reported smoking tobacco. Using negative-binomial regression, we estimated rates of reported ED/UC visits and specific illnesses among children with marijuana exposure and those with tobacco exposure, compared to unexposed children. Caregivers who used marijuana reported an increased rate of VRIs in their children (1.31 episodes/year) compared to caregivers with no marijuana use (1.04 episodes/year) (p = 0.02). CONCLUSIONS: Our cohort did not report any difference with ED/UC visits, otitis media episodes, or asthma exacerbations, regardless of smoke exposure. However, caregivers of children with secondhand marijuana smoke exposure reported increased VRIs compared to children with no smoke exposure. IMPACT: Approximately 10% of caregivers in our study were regular users of marijuana. Prior studies have shown that secondhand tobacco smoke exposure is associated with negative health outcomes in children, including increased ED utilization and respiratory illnesses. Prior studies have shown primary marijuana use is linked to negative health outcomes in adults and adolescents, including increased ED utilization and respiratory illnesses. Our study reveals an association between secondhand marijuana smoke exposure and increased VRIs in children. Our study did not find an association between secondhand marijuana smoke exposure and increased ED or UC visitation in children.

Prevalence of chronic opioid use in patients with peripheral arterial disease undergoing revascularization.

OBJECTIVE: Opiate use, dependence, and the associated morbidity and mortality are major current public health problems in the United States. Little is known about patterns of opioid use in patients with peripheral arterial disease (PAD). The purpose of this study was to identify the prevalence of chronic preoperative and postoperative prescription opioid use in patients with PAD. A secondary aim was to determine the demographic, comorbid conditions, and operative characteristics associated with chronic opioid use. METHODS: Using a single-institution database of patients with PAD undergoing open or endovascular lower extremity intervention from 2013 to 2014, data regarding opiate use and associated conditions were abstracted for analysis. Patients were excluded if they did not live in North Carolina or surgery was not for PAD. Preoperative (PreCOU) and postoperative chronic opioid use (PostCOU) were defined as consistent opioid prescription filling in the 3 months before and after the index procedure, respectively. Opioid prescription filling was assessed using the North Carolina Controlled Substance Reporting System. Demographics, comorbid conditions, other adjunct pain medication data, and operative characteristics were abstracted from our institutional electronic medical record. Associations with PreCOU were evaluated using the t test, Wilcoxon test, or two-sample median test (continuous), or the χ2 or Fisher exact tests (categorical). RESULTS: A total of 202 patients undergoing open (108; 53.5%) or endovascular (94; 46.5%) revascularization for claudication or critical limb ischemia were identified for analysis. The mean age was 64.6 years, and 36% were female. Claudication was the indication for revascularization in 26.7% of patients, and critical limb ischemia was the indication in 73.3% of patients. The median preoperative ankle-brachial index (ABI) was 0.50. Sixty-eight patients (34%) met the definition for PreCOU. PreCOU was associated with female gender, history of chronic musculoskeletal pain, benzodiazepine use, and self-reported illicit drug use. Less than 50% of patients reported use of non-opiate adjunct pain medications. No association was observed between PreCOU and pre- or postoperative ABI, or number of prior lower extremity interventions. Following revascularization, the median ABI was 0.88. PreCOU was not associated with significant differences in postoperative complications, length of stay, or mortality. Overall, 71 patients (35%) met the definition for PostCOU, 14 of whom had no history of preoperative chronic opiate use. Ten patients with PreCOU did not demonstrate PostCOU. CONCLUSIONS: Chronic opiate use was common in patients with PAD with a prevalence of approximately 35%, both prior to and following revascularization. Revascularization was associated with a termination of chronic opiate use in less than 15% of patients with PreCOU. Additionally, 10% of patients who did not use opiates chronically before their revascularization did so afterwards. Patients with PAD requiring intervention represent a high-risk group with regards to chronic opiate use. Increased diligence in identifying opioid use among patients with PAD and optimizing the use of non-narcotic adjunct pain medications may result in a lower prevalence of chronic opiate use and its attendant adverse effects.

Isolating Conformers to Assess Dynamics of Peptidic Catalysts Using Computationally Designed Macrocyclic Peptides.

Studying the relationship between catalyst conformational dynamics and selectivity in an asymmetric reaction is a challenge. In this study, cyclic peptides were computationally designed to stabilize different ground state conformations of a highly effective, flexible tetrapeptide catalyst for the atroposelective bromination of N-aryl quinazolinones. Through a combination of computational and experimental techniques, we have determined that dynamic movement of the lead catalyst plays a crucial role in achieving high enantioselectivity in the reaction of study. This approach may also serve as a valuable method for investigating the mechanism of other peptide-catalyzed transformations.

Anchor extension: a structure-guided approach to design cyclic peptides targeting enzyme active sites.

Despite recent success in computational design of structured cyclic peptides, de novo design of cyclic peptides that bind to any protein functional site remains difficult. To address this challenge, we develop a computational "anchor extension" methodology for targeting protein interfaces by extending a peptide chain around a non-canonical amino acid residue anchor. To test our approach using a well characterized model system, we design cyclic peptides that inhibit histone deacetylases 2 and 6 (HDAC2 and HDAC6) with enhanced potency compared to the original anchor (IC50 values of 9.1 and 4.4 nM for the best binders compared to 5.4 and 0.6 µM for the anchor, respectively). The HDAC6 inhibitor is among the most potent reported so far. These results highlight the potential for de novo design of high-affinity protein-peptide interfaces, as well as the challenges that remain.

The role of body mass index on quality indicators following minimally-invasive radical prostatectomy.

PURPOSE: We sought to determine the role of body mass index (BMI) on quality indicators, such as length of stay and readmission. The National Surgical Quality Improvement Program (NSQIP) database was queried to examine the effect of obesity, defined as BMI >30, on outcomes after Minimally Invasive Radical Retropubic Prostatectomy (MI-RRP). MATERIALS AND METHODS: Utilizing the NSQIP database, patient records were identified using the Current Procedural Terminology (CPT) code 55866 (laparoscopy, surgical prostatectomy, radical retropubic) during a 10-year period (2007-2017). Obesity was classified according to the CDC classification. Chi-square tests were utilized to evaluate BMI distribution by surgery year. Logistic regression was used to evaluate the relationship of BMI with length of stay (LOS) and hospital readmission within 30 days, after controlling for preoperative variables. RESULTS: Records of 49,238 patients who have undergone MI-RRP during 2007-2017 were evaluated. Mean yearly BMI rose from 28.5 to 29.2, while the percentage of surgical patients with BMI >30 rose by 5% (33% to 38%; p<0.0001) over the study period. Obese patients demonstrated higher morbidity, prolonged LOS, and increased readmission rates after MI-RRP. Obesity severity correlated negatively with quality indicators in a graded fashion. CONCLUSIONS: Obesity rates in patients undergoing MI-RRP increased from 2007-2017. Obese patients are at increased risk of morbidity, prolonged LOS, and readmission within 30 days, following MI-RRP. These patients should not be excluded from MI-RRP; rather, physicians should discuss these increased risks with their patients. Proper weight loss strategies should be instituted preoperatively to mitigate these risks.

Computationally designed peptide macrocycle inhibitors of New Delhi metallo-ß-lactamase 1.

The rise of antibiotic resistance calls for new therapeutics targeting resistance factors such as the New Delhi metallo-ß-lactamase 1 (NDM-1), a bacterial enzyme that degrades ß-lactam antibiotics. We present structure-guided computational methods for designing peptide macrocycles built from mixtures of l- and d-amino acids that are able to bind to and inhibit targets of therapeutic interest. Our methods explicitly consider the propensity of a peptide to favor a binding-competent conformation, which we found to predict rank order of experimentally observed IC50 values across seven designed NDM-1- inhibiting peptides. We were able to determine X-ray crystal structures of three of the designed inhibitors in complex with NDM-1, and in all three the conformation of the peptide is very close to the computationally designed model. In two of the three structures, the binding mode with NDM-1 is also very similar to the design model, while in the third, we observed an alternative binding mode likely arising from internal symmetry in the shape of the design combined with flexibility of the target. Although challenges remain in robustly predicting target backbone changes, binding mode, and the effects of mutations on binding affinity, our methods for designing ordered, binding-competent macrocycles should have broad applicability to a wide range of therapeutic targets.

O-GlcNAc modification of small heat shock proteins enhances their anti-amyloid chaperone activity.

A major role for the intracellular post-translational modification O-GlcNAc appears to be the inhibition of protein aggregation. Most of the previous studies in this area focused on O-GlcNAc modification of the amyloid-forming proteins themselves. Here we used synthetic protein chemistry to discover that O-GlcNAc also activates the anti-amyloid activity of certain small heat shock proteins (sHSPs), a potentially more important modification event that can act broadly and substoichiometrically. More specifically, we found that O-GlcNAc increases the ability of sHSPs to block the amyloid formation of both α-synuclein and Aß(1-42). Mechanistically, we show that O-GlcNAc near the sHSP IXI-domain prevents its ability to intramolecularly compete with substrate binding. Finally, we found that, although O-GlcNAc levels are globally reduced in Alzheimer's disease brains, the modification of relevant sHSPs is either maintained or increased, which suggests a mechanism to maintain these potentially protective O-GlcNAc modifications. Our results have important implications for neurodegenerative diseases associated with amyloid formation and potentially other areas of sHSP biology.

Patient Health Utility Equations for a Type 2 Diabetes Model.

OBJECTIVE: To estimate the health utility impact of diabetes-related complications in a large, longitudinal U.S. sample of people with type 2 diabetes. RESEARCH DESIGN AND METHODS: We combined Health Utilities Index Mark 3 data on patients with type 2 diabetes from the Action to Control Cardiovascular Risk in Diabetes (ACCORD) and Look AHEAD (Action for Health in Diabetes) trials and their follow-on studies. Complications were classified as events if they occurred in the year preceding the utility measurement; otherwise, they were classified as a history of the complication. We estimated utility decrements associated with complications using a fixed-effects regression model. RESULTS: Our sample included 15,252 persons with an average follow-up of 8.2 years and a total of 128,873 person-visit observations. The largest, statistically significant (P < 0.05) health utility decrements were for stroke (event, -0.109; history, -0.051), amputation (event, -0.092; history, -0.150), congestive heart failure (event, -0.051; history, -0.041), dialysis (event, -0.039), estimated glomerular filtration rate (eGFR) <30 mL/min/1.73 m2 (event, -0.043; history, -0.025), angina (history, -0.028), and myocardial infarction (MI) (event, -0.028). There were smaller effects for laser photocoagulation and eGFR <60 mL/min/1.73 m2. Decrements for dialysis history, angina event, MI history, revascularization event, revascularization history, laser photocoagulation event, and hypoglycemia were not significant (P ≥ 0.05). CONCLUSIONS: With use of a large study sample and a longitudinal design, our estimated health utility scores are expected to be largely unbiased. Estimates can be used to describe the health utility impact of diabetes complications, improve cost-effectiveness models, and inform diabetes policies.