ABSTRACT
INTRODUCTION: Inadequate clinical training site availability may inhibit physician assistant/associate (PA), advanced practice nursing (APN), and physician workforce growth. Educational institutions increasingly incentivize clinical training sites with financial compensation, with potential implications for educational costs and enrollment. This study investigated compensation trends among PA programs. METHODS: Data from the 2013 to 2019 PA Education Association Program Reports were examined. Multivariate logistic and linear regressions were estimated to identify the influence of PA program characteristics on clinical training site compensation. The effect of compensation on program enrollment was determined with a difference-in-differences estimator. RESULTS: Physician assistant/associate programs collectively paid nearly $19 million to clinical training sites in 2019. The percentage of programs that offer financial incentives increased from 22.2% in 2013 to 52.3% in 2019. Over this time, public institutions affiliated with academic health centers (AHCs) were least likely to offer compensation. Higher compensation rates were observed in Census divisions with greater number of programs, and programs located in New England were the most likely to offer compensation. Offering compensation did not influence growth in programs' enrollment. DISCUSSION: Compensation trends highlight increasing demand for PA clinical training sites, especially in areas with greater regional competition. Compensation is primarily driven by private institutions unaffiliated with AHCs. Programs likely offer compensation to maintain, rather than grow, enrollment. Additional investigation should incorporate medical school and APN program data to more fully examine the impact of these costs on learners, institutions, and the health care workforce.
ABSTRACT
Cysteine-focused chemical proteomic platforms have accelerated the clinical development of covalent inhibitors for a wide range of targets in cancer. However, how different oncogenic contexts influence cysteine targeting remains unknown. To address this question, we have developed "DrugMap," an atlas of cysteine ligandability compiled across 416 cancer cell lines. We unexpectedly find that cysteine ligandability varies across cancer cell lines, and we attribute this to differences in cellular redox states, protein conformational changes, and genetic mutations. Leveraging these findings, we identify actionable cysteines in NF-κB1 and SOX10 and develop corresponding covalent ligands that block the activity of these transcription factors. We demonstrate that the NF-κB1 probe blocks DNA binding, whereas the SOX10 ligand increases SOX10-SOX10 interactions and disrupts melanoma transcriptional signaling. Our findings reveal heterogeneity in cysteine ligandability across cancers, pinpoint cell-intrinsic features driving cysteine targeting, and illustrate the use of covalent probes to disrupt oncogenic transcription-factor activity.
Subject(s)
Cysteine , Neoplasms , Animals , Humans , Mice , Cell Line, Tumor , Cysteine/metabolism , Cysteine/chemistry , Ligands , Melanoma/metabolism , Neoplasms/drug therapy , Neoplasms/metabolism , NF-kappa B/chemistry , NF-kappa B/metabolism , Oxidation-Reduction , Signal Transduction , SOXE Transcription Factors/chemistry , SOXE Transcription Factors/metabolismABSTRACT
High labor demand for physician assistants/associates (PA) has led to substantial PA workforce and wage growth. During this growth period, states have adopted reforms to reduce PA scope of practice restrictions and reports of significant gender and race wage disparities have emerged. This study examined data from the American Community Survey to investigate the influence of demographic characteristics, human capital, and scope of practice reforms on PA wages from 2008 to 2017. Using an ordinary least squares two-way fixed effects estimator, a significant association between reforms and PA wages could not be established. Rather, wages were found to be strongly associated with human capital and demographic characteristics. Gender and race wage disparities persist, with female PAs earning 7.5% lower wages than male PAs and White PAs earning 9.1% to 14.5% higher wages than racial and ethnic minority PAs. These findings suggest a minimal influence of prior scope of practice reforms on PA wages.
Subject(s)
Ethnicity , Physician Assistants , Humans , Male , Female , United States , Scope of Practice , Minority Groups , Salaries and Fringe BenefitsABSTRACT
The retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt), which is a promising therapeutic target for immune diseases, is a major transcription factor of genes related to psoriasis pathogenesis, such as interleukin (IL)-17A, IL-22, and IL-23R. Inspired by the co-crystal structure of RORγt, a 6-oxo-4-phenyl-hexanoic acid derivative 6a was designed, synthesized, and identified as a ligand of RORγt. The structure-activity relationship (SAR) studies in 6a, which focus on the improvement of its membrane permeability profile by introducing chlorine atoms, led to finding 12a, which has a potent RORγt inhibitory activity and a favorable pharmacokinetic profile.
Subject(s)
Caproates/pharmacology , Drug Discovery , Nuclear Receptor Subfamily 1, Group F, Member 3/agonists , Animals , Caproates/chemistry , Caproates/metabolism , Dose-Response Relationship, Drug , Humans , Mice , Microsomes, Liver/chemistry , Microsomes, Liver/metabolism , Molecular Structure , Nuclear Receptor Subfamily 1, Group F, Member 3/genetics , Structure-Activity RelationshipABSTRACT
The retinoic acid receptor-related orphan nuclear receptor γt (RORγt), a promising therapeutic target, is a major transcription factor of genes related to psoriasis pathogenesis such as interleukin (IL)-17A, IL-22, and IL-23R. On the basis of the X-ray cocrystal structure of RORγt with 1a, an analogue of the known piperazine RORγt inverse agonist 1, triazolopyridine derivatives of 1 were designed and synthesized, and analogue 3a was found to be a potent RORγt inverse agonist. Structure-activity relationship studies on 3a, focusing on the treatment of its metabolically unstable cyclopentyl ring and the central piperazine core, led to a novel analogue, namely, 6-methyl-N-(7-methyl-8-(((2S,4S)-2-methyl-1-(4,4,4-trifluoro-3-(trifluoromethyl)butanoyl)piperidin-4-yl)oxy)[1,2,4]triazolo[1,5-a]pyridin-6-yl)nicotinamide (5a), which exhibited strong RORγt inhibitory activity and a favorable pharmacokinetic profile. Moreover, the in vitro and in vivo evaluation of 5a in a human whole-blood assay and a mouse IL-18/23-induced cytokine expression model revealed its robust and dose-dependent inhibitory effect on IL-17A production.
ABSTRACT
The detection of atrial fibrillation (AF) is important for stroke prevention in patients with AF. This paper aimed to investigate the current landscape of smartphone-based arrhythmia detection and monitoring. The current technology can be divided into smartphone-based photoplethysmography (PPG) and smartphone-based single-lead electrocardiograms (ECGs). Our literature review concluded there are currently no validated PPG applications for the detection of arrhythmias available to the general population. However, an initial validation study indicates that the current development in Cardiio Rhythm PPG application, when made available, could provide an accurate and reliable means to detect AF in patients at risk of developing AF. The smartphone-based single-lead ECG devices are more promising. Multiple studies have shown the AliveCor smartphone ECG to be a reliable and accurate means of detecting atrial fibrillation. A drawback is that this device strictly provides data and is not capable of making a diagnosis of atrial fibrillation. The recorded ECG needs to be sent to a physician or medical professional for further review. In conclusion, these devices show promise in arrhythmia assessment, managing patients with AF, and diagnosing AF early in high risk patients. Caution should be used when assessing data provided by these devices, as validation in a real-world setting is still underway.
ABSTRACT
As part of an ongoing effort at Amgen to develop a disease-modifying therapy for Alzheimer's disease, we have previously used the aminooxazoline xanthene (AOX) scaffold to generate potent and orally efficacious BACE1 inhibitors. While AOX-BACE1 inhibitors demonstrated acceptable cardiovascular safety margins, a retinal pathological finding in rat toxicological studies demanded further investigation. It has been widely postulated that such retinal toxicity might be related to off-target inhibition of Cathepsin D (CatD), a closely related aspartyl protease. We report the development of AOX-BACE1 inhibitors with improved selectivity against CatD by following a structure- and property-based approach. Our efforts culminated in the discovery of a picolinamide-substituted 3-aza-AOX-BACE1 inhibitor absent of retinal effects in an early screening rat toxicology study.
ABSTRACT
Pancreatic amyloid formation by islet amyloid polypeptide (IAPP) is a hallmark pathological feature of type 2 diabetes. IAPP is stored in the secretory granules of pancreatic beta-cells and co-secreted with insulin to maintain glucose homeostasis. IAPP is innocuous under homeostatic conditions but imbalances in production or processing of IAPP may result in homodimer formation leading to the rapid production of cytotoxic oligomers and amyloid fibrils. The consequence is beta-cell dysfunction and the accumulation of proteinaceous plaques in and around pancreatic islets. Beta-site APP-cleaving enzyme 2, BACE2, is an aspartyl protease commonly associated with BACE1, a related homolog responsible for amyloid processing in the brain and strongly implicated in Alzheimer's disease. Herein, we identify two distinct sites of the mature human IAPP sequence that are susceptible to BACE2-mediated proteolytic activity. The result of proteolysis is modulation of human IAPP fibrillation and human IAPP protein degradation. These results suggest a potential therapeutic role for BACE2 in type 2 diabetes-associated hyperamylinaemia.
Subject(s)
Amyloid Precursor Protein Secretases/metabolism , Aspartic Acid Endopeptidases/metabolism , Islet Amyloid Polypeptide/metabolism , Amino Acid Sequence , Amyloid Precursor Protein Secretases/antagonists & inhibitors , Animals , Aspartic Acid Endopeptidases/antagonists & inhibitors , Cell Line , Diabetes Mellitus, Type 2/genetics , Diabetes Mellitus, Type 2/metabolism , Diabetes Mellitus, Type 2/pathology , Humans , Insulin/metabolism , Insulin/pharmacology , Insulin-Secreting Cells/metabolism , Insulin-Secreting Cells/pathology , Islet Amyloid Polypeptide/chemistry , Islet Amyloid Polypeptide/genetics , Mass Spectrometry , Mice , Molecular Sequence Data , Mutation , Plaque, Amyloid/metabolism , Proteolysis/drug effects , Recombinant Proteins , Substrate SpecificityABSTRACT
Clinical trials have reported a low time in therapeutic range (TTR) in patients with atrial fibrillation treated with both warfarin andamiodarone. These trials included centers and countries with both high and low TTRs. What is the impact of amiodarone on the TTR in a single, high-quality anticoagulation clinic? TTR was assessed in amiodarone and nonamiodarone-treated patients from a University anticoagulation clinic. Baseline characteristics between patients ever-taking or never-taking amiodarone were similar, except more amiodarone patients were smokers (19.5 vs. 6.1%, Pâ=â0.0031). The TTR calculated from 8901international normalized ratios (INRs) in 249 nonamiodarone patients with a mean follow-up of 34â±â20 months (mean INR 36â±â18) was 66â±â16.6% compared with 61.3â±â16.2% (Pâ=â0.111) from 1455 INRs in 41 amiodarone-treated patients with a mean follow-up of 28â±â20 months (mean INR 35â±â22). Factors associated with a low TTR were male sex (Pâ=â0.0013), smoker (Pâ=â0.0048), and amiodarone use (Pâ=â0.0374). A second on-treatment analysis, in which the TTR was calculated only during amiodarone therapy, resulted in similar findings; however, amiodarone did not emerge as a predictor of a low TTR. In 11 patients, the TTR prior to amiodarone (54.5â±â22.2%) was not significantly different in the first 3 months (54.6â±â33.4%) or after 3 months (67.2â±â33.7%) of amiodarone. In a single high-quality anticoagulation center, anticoagulation quality, as measured by the TTR, can be comparable in amiodarone and nonamiodarone-treated patients.
Subject(s)
Amiodarone/therapeutic use , Anticoagulants/therapeutic use , Atrial Fibrillation/drug therapy , Thromboembolism/drug therapy , Warfarin/therapeutic use , Aged , Aged, 80 and over , Atrial Fibrillation/blood , Atrial Fibrillation/complications , Atrial Fibrillation/pathology , Drug Combinations , Female , Follow-Up Studies , Humans , International Normalized Ratio , Male , Middle Aged , Sex Factors , Smoking , Thromboembolism/blood , Thromboembolism/complications , Thromboembolism/pathology , Time Factors , Treatment OutcomeABSTRACT
BACE1 inhibition to prevent Aß peptide formation is considered to be a potential route to a disease-modifying treatment for Alzheimer's disease. Previous efforts in our laboratory using a combined structure- and property-based approach have resulted in the identification of aminooxazoline xanthenes as potent BACE1 inhibitors. Herein, we report further optimization leading to the discovery of inhibitor 15 as an orally available and highly efficacious BACE1 inhibitor that robustly reduces CSF and brain Aß levels in both rats and nonhuman primates. In addition, compound 15 exhibited low activity on the hERG ion channel and was well tolerated in an integrated cardiovascular safety model.
ABSTRACT
The ß-site amyloid precursor protein (APP) cleaving enzyme 1 (BACE1) is one of the most hotly pursued targets for the treatment of Alzheimer's disease. We used a structure- and property-based drug design approach to identify 2-aminooxazoline 3-azaxanthenes as potent BACE1 inhibitors which significantly reduced CSF and brain Aß levels in a rat pharmacodynamic model. Compared to the initial lead 2, compound 28 exhibited reduced potential for QTc prolongation in a non-human primate cardiovascular safety model.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Aspartic Acid Endopeptidases/antagonists & inhibitors , Protease Inhibitors/chemistry , Protease Inhibitors/pharmacology , Xanthenes/chemistry , Xanthenes/pharmacology , Alzheimer Disease/drug therapy , Animals , Cell Line , HEK293 Cells , Humans , Protease Inhibitors/chemical synthesis , Rats , Xanthenes/chemical synthesisABSTRACT
We have previously shown that the aminooxazoline xanthene scaffold can generate potent and orally efficacious BACE1 inhibitors although certain of these compounds exhibited potential hERG liabilities. In this article, we describe 4-aza substitution on the xanthene core as a means to increase BACE1 potency while reducing hERG binding affinity. Further optimization of the P3 and P2' side chains resulted in the identification of 42 (AMG-8718), a compound with a balanced profile of BACE1 potency, hERG binding affinity, and Pgp recognition. This compound produced robust and sustained reductions of CSF and brain Aß levels in a rat pharmacodynamic model and exhibited significantly reduced potential for QTc elongation in a cardiovascular safety model.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Aspartic Acid Endopeptidases/antagonists & inhibitors , Benzopyrans/chemical synthesis , Protease Inhibitors/chemical synthesis , Pyridines/chemical synthesis , Spiro Compounds/chemical synthesis , Amyloid beta-Peptides/metabolism , Animals , Benzopyrans/pharmacology , Ether-A-Go-Go Potassium Channels/drug effects , HEK293 Cells , Humans , Inhibitory Concentration 50 , Microsomes, Liver/metabolism , Pyridines/pharmacology , Rats, Sprague-Dawley , Spiro Compounds/pharmacology , Structure-Activity RelationshipABSTRACT
The optimization of a series of aminooxazoline xanthene inhibitors of ß-site amyloid precursor protein cleaving enzyme 1 (BACE1) is described. An early lead compound showed robust Aß lowering activity in a rat pharmacodynamic model, but advancement was precluded by a low therapeutic window to QTc prolongation in cardiovascular models consistent with in vitro activity on the hERG ion channel. While the introduction of polar groups was effective in reducing hERG binding affinity, this came at the expense of higher than desired Pgp-mediated efflux. A balance of low Pgp efflux and hERG activity was achieved by lowering the polar surface area of the P3 substituent while retaining polarity in the P2' side chain. The introduction of a fluorine in position 4 of the xanthene ring improved BACE1 potency (5-10-fold). The combination of these optimized fragments resulted in identification of compound 40, which showed robust Aß reduction in a rat pharmacodynamic model (78% Aß reduction in CSF at 10 mg/kg po) and also showed acceptable cardiovascular safety in vivo.
Subject(s)
Amyloid Precursor Protein Secretases/antagonists & inhibitors , Aspartic Acid Endopeptidases/antagonists & inhibitors , Ether-A-Go-Go Potassium Channels/metabolism , Oxazolone/analogs & derivatives , Protease Inhibitors/chemical synthesis , Xanthenes/chemical synthesis , Animals , Crystallography, X-Ray , HEK293 Cells , Humans , Inhibitory Concentration 50 , Male , Microsomes, Liver/metabolism , Oxazolone/chemical synthesis , Oxazolone/pharmacology , Rats, Sprague-Dawley , Structure-Activity Relationship , Xanthenes/pharmacologyABSTRACT
Background: Inflammation is considered to be a major initiator to angioplasty-induced vascular restenosis. Proinflammatory cytokines stimulate vascular smooth muscle cell (VSMC) migration and proliferation leading to neointimal hyperplasia. It has been reported that chronic caffeine use suppresses the production of proinflammatory cytokine TNF-α (tumor necrosis factor Alpha) and alters adenosine receptor expression in human neutrophils, indicating that caffeine may attenuate vascular injury-induced inflammation and subsequent neointimal hyperplasia. Our current study was designed to test the hypothesis that chronic caffeine treatment decreases vascular injury-induced neointimal hyperplasia by suppressing VSMC migration and proliferation. Methods and Results: The experiments were carried out using both in vivo (rat carotid artery injury model) and in vitro (VSMCs isolated from rat aorta) models. Male Sprague-Dawley rats that received chronic caffeine treatment (10 and 20 mg/kg per day, through oral gavage) showed a significant decrease in neointimal hyperplasia when compared to rats that received vehicle. To understand the underlying mechanisms, we tested if caffeine inhibits fetal bovine serum (FBS)-induced VSMC migration and proliferation. We found that caffeine substantially suppressed FBS-induced VSMC migration and proliferation. The attenuation of FBS-stimulated cell migration is dose dependent. Conclusion: Together, our results suggest that chronic treatment with high concentrations of caffeine attenuates vascular injury-induced neointimal hyperplasia by suppressing smooth muscle cell migration and proliferation in rats.
ABSTRACT
A series of alpha-amidosulfones were found to be potent and selective agonists of CB(2). The discovery, synthesis, and structure-activity relationships of this series of agonists are reported. In addition, the pharmacokinetic properties of the most promising compounds are profiled.
Subject(s)
Receptor, Cannabinoid, CB2/agonists , Sulfones/chemistry , Amides/chemistry , Amides/pharmacology , Animals , Humans , Microsomes, Liver , Pharmacokinetics , Rats , Structure-Activity Relationship , Sulfones/pharmacologyABSTRACT
The CB2 receptor is an attractive therapeutic target for analgesic and anti-inflammatory agents. Herein we describe the discovery of a novel class of oxadiazole derivatives from which potent and selective CB2 agonist leads were developed. Initial hit 7 was identified from a cannabinoid target-biased library generated by virtual screening of sample collections using a pharmacophore model in combination with a series of physicochemical filters. 7 was demonstrated to be a selective CB2 agonist (CB2 EC50 = 93 nM, Emax = 98%, CB1 EC50 > 10 microM). However, this compound exhibited poor solubility and relatively high clearance in rat, resulting in low oral bioavailability. In this paper, we report detailed SAR studies on 7 en route toward improving potency, physicochemical properties, and solubility. This effort resulted in identification of 63 that is a potent and selective agonist at CB2 (EC50 = 2 nM, Emax = 110%) with excellent pharmacokinetic properties.
Subject(s)
Aminoquinolines/chemical synthesis , Oxadiazoles/chemical synthesis , Receptor, Cannabinoid, CB2/agonists , Administration, Oral , Aminoquinolines/administration & dosage , Aminoquinolines/pharmacokinetics , Animals , Biological Availability , CHO Cells , Cricetinae , Cricetulus , Drug Evaluation, Preclinical , Humans , Models, Molecular , Oxadiazoles/administration & dosage , Oxadiazoles/pharmacokinetics , Rats , Structure-Activity RelationshipABSTRACT
Structural modifications to the central portion of the N-arylamide oxadiazole scaffold led to the identification of N-arylpiperidine oxadiazoles as conformationally constrained analogs that offered improved stability and comparable potency and selectivity. The simple, modular scaffold allowed for the use of expeditious and divergent synthetic routes, which provided two-directional SAR in parallel. Several potent and selective agonists from this novel ligand class are described.
Subject(s)
Microsomes, Liver/metabolism , Oxadiazoles , Receptor, Cannabinoid, CB2/agonists , Animals , Combinatorial Chemistry Techniques , Humans , Molecular Conformation , Molecular Structure , Oxadiazoles/chemical synthesis , Oxadiazoles/chemistry , Oxadiazoles/pharmacokinetics , Oxadiazoles/pharmacology , Rats , Structure-Activity RelationshipABSTRACT
Inhibition of c-Kit has the potential to treat mast cell associated fibrotic diseases. We report the discovery of several aminoquinazoline pyridones that are potent inhibitors of c-Kit with greater than 200-fold selectivity against KDR, p38, Lck, and Src. In vivo efficacy of pyridone 16 by dose-dependent inhibition of histamine release was demonstrated in a rodent pharmacodynamic model of mast cell activation.
Subject(s)
Protein Kinase Inhibitors/chemical synthesis , Proto-Oncogene Proteins c-kit/metabolism , Pyridones/chemical synthesis , Quinazolines/chemical synthesis , Administration, Oral , Animals , Crystallography, X-Ray , Histamine Release/drug effects , Mast Cells/drug effects , Mast Cells/metabolism , Models, Molecular , Molecular Structure , Protein Kinase Inhibitors/pharmacokinetics , Protein Kinase Inhibitors/pharmacology , Pyridones/pharmacokinetics , Pyridones/pharmacology , Quinazolines/pharmacokinetics , Quinazolines/pharmacology , Rats , Structure-Activity RelationshipABSTRACT
A series of naphthyl-based compounds were synthesized as potential inhibitors of vascular endothelial growth factor (VEGF) receptors. Investigations of structure-activity relationships led to the identification of a series of naphthamides that are potent inhibitors of the VEGF receptor tyrosine kinase family. Numerous analogues demonstrated low nanomolar inhibition of VEGF-dependent human umbilical vein endothelial cell (HUVEC) proliferation, and of these several compounds possessed favorable pharmacokinetic (PK) profiles. In particular, compound 48 demonstrated significant antitumor efficacy against established HT29 human colon adenocarcinoma xenografts implanted in athymic mice. A full account of the preparation, structure-activity relationships, pharmacokinetic properties, and pharmacology of analogues within this series is presented.