MHC class I-specific reagents such as fluorescently-labeled multimers (e.g., tetramers) have greatly advanced the understanding of CD8+ T cells under normal and diseased states. However, recombinant MHC class I components (comprising MHC class I heavy chain and β2 microglobulin) are usually produced in bacteria following a lengthy purification protocol that requires additional non-covalent folding steps with exogenous peptide for complete molecular assembly. We have provided an alternative and rapid approach to generating soluble and fully-folded MHC class I molecules in eukaryotic cell lines (such as CHO cells) using a Sleeping Beauty transposon system. Importantly, this method culminates in generating stable cell lines that reliably secrete epitope-defined MHC class I molecules into the tissue media for convenient purification and eventual biotinylation/multimerization. Additionally, MHC class I components are covalently linked, providing the opportunity to produce a diverse set of CD8+ T cell-specific reagents bearing peptides with various affinities to MHC class I.
Publications
2019
Deprescribing, an integral component of a continuum of good prescribing practices, is the process of medication withdrawal or dose reduction to correct or prevent medication-related complications, improve outcomes, and reduce costs. Deprescribing is particularly applicable to the commonly encountered multimorbid older adult with cardiovascular disease and concomitant geriatric conditions such as polypharmacy, frailty, and cognitive dysfunction-a combination rarely addressed in current clinical practice guidelines. Triggers to deprescribe include present or expected adverse drug reactions, unnecessary polypharmacy, and the need to align medications with goals of care when life expectancy is reduced. Using a framework to deprescribe, this review addresses the rationale, evidence, and strategies for deprescribing cardiovascular and some noncardiovascular medications.
PURPOSE: Pharmacy dispensing databases are often used to identify patients' medications at a particular time point, for example to measure prescribing quality or the impact of medication use on clinical outcomes. We performed a systematic review of studies that examined methods to assess medications in use at a specific point in time.
METHODS: Comprehensive literature search to identify studies that compared active medications identified using pharmacy databases to medications identified using nonautomated data sources. Two investigators independently reviewed abstracts and full-text material.
RESULTS: Of 496 studies screened, 29 studies evaluating 50 comparisons met inclusion criteria. Twenty-nine comparisons evaluated fixed look-back period approaches, defining active medications as those filled in a specified period prior to the index date (range 84-730 days). Fourteen comparisons evaluated medication-on-hand approaches, defining active medications as those for which the most recent fill provided sufficient supply to last through the study index date. Sensitivity ranged from 48% to 93% for fixed look-back period approaches and 35% to 97% for medication-on-hand approaches. Interpretation of comparative performance of methods was limited by use of different reference sources, target medication classes, and databases across studies. In four studies with head-to-head comparisons of these methods, sensitivity of the medication-on-hand approach was a median of 7% lower than the corresponding fixed look-back approach.
CONCLUSIONS: The reported accuracy of methods for identifying active medications using pharmacy databases differs greatly across studies. More direct comparisons of common approaches are needed to establish the accuracy of methods within and across populations, medication classes, and databases.
BACKGROUND: Rapid syphilis tests (RST) may shorten time to syphilis diagnosis and treatment while enhancing access to testing in outreach settings. There are limited data on the performance of RST in outreach settings in the US.
METHODS: We offered RST (Syphilis Health Check) at 6 outreach sites to men who reported having sex with men and no prior history of syphilis. Clients accepting RST were also tested with laboratory-based rapid plasma reagin (RPR) and reflex Treponema pallidum particle agglutination (TPPA) assay when RPR or RST were positive. Clients with positive RST were immediately referred to a sexually transmitted infection clinic. Those declining RST were screened with RPR and reflex TPPA only. The validity of the RST-based algorithm was compared with the RPR-based algorithm among participants receiving both. Time to treatment for those accepting RST was compared with those declining RST and to a historical control group screened in outreach settings with RPR and reflex TPPA before the availability of RST.
RESULTS: Rapid syphilis test was accepted by 690 (64%) of 1081 eligible clients. Compared with RPR-based algorithm, RST sensitivity was 90%; specificity, 98.5%; positive predictive value, 47.4%; and negative predictive value, 98.5. The single false-negative case by RST was determined to be a late latent case by RPR/TPPA. Median time to treatment was 1 day (range, 0-6 days) for 9 of 690 accepting RST, compared to 9 days (range, 7-13 days) for 3 of 391 declining RST, and 9 days (range, 6-21 days) for 25 of 1229 historical controls (P < 0.0001).
CONCLUSION: Compared with an RPR-based algorithm, RST identified all early syphilis cases. Although RST had high specificity and negative predictive value, the low positive predictive value resulted in additional assessments in a sexually transmitted infection clinic for some patients. However, RST use in outreach settings significantly decreased time to treatment for new syphilis cases.
BACKGROUND: Pharmacy dispensing data are frequently used to identify prevalent medication use as a predictor or covariate in observational research studies. Although several methods have been proposed for using pharmacy dispensing data to identify prevalent medication use, little is known about their comparative performance.
OBJECTIVES: The authors sought to compare the performance of different methods for identifying prevalent outpatient medication use.
RESEARCH DESIGN: Outpatient pharmacy fill data were compared with medication reconciliation notes denoting prevalent outpatient medication use at the time of hospital admission for a random sample of 207 patients drawn from a national cohort of patients admitted to Veterans Affairs hospitals. Using reconciliation notes as the criterion standard, we determined the test characteristics of 12 pharmacy database algorithms for determining prevalent use of 11 classes of cardiovascular and diabetes medications.
RESULTS: The best-performing algorithms included a 180-day fixed look-back period approach (sensitivity, 93%; specificity, 97%; and positive predictive value, 89%) and a medication-on-hand approach with a grace period of 60 days (sensitivity, 91%; specificity, 97%; and positive predictive value, 91%). Algorithms that have been commonly used in previous studies, such as defining prevalent medications to include any medications filled in the prior year or only medications filled in the prior 30 days, performed less well. Algorithm performance was less accurate among patients recently receiving hospital or nursing facility care.
CONCLUSION: Pharmacy database algorithms that balance recentness of medication fills with grace periods performed better than more simplistic approaches and should be considered for future studies which examine prevalent chronic medication use.
Problem: Although scholarship during residency training is an important requirement from the Accreditation Council for Graduate Medical Education, efforts to support resident scholarship have demonstrated inconsistent effects and have not comprehensively evaluated resident experiences. Intervention: We developed the Leadership and Discovery Program (LEAD) to facilitate scholarship among all non-research-track categorical internal medicine (IM) residents. This multifaceted program set expectations for all residents to participate in a scholarly project, supported faculty to manage the program, facilitated access to faculty mentors, established a local resident research day to highlight scholarship, and developed a didactic lecture series. Context: We implemented LEAD at a large university training program. We assessed resident scholarship before and after LEAD implementation using objective metrics of academic productivity (i.e., scientific presentations, peer-reviewed publications, and both presentations and publications). We compared these metrics in LEAD participants and a similar historical group of pre-LEAD controls. We also assessed these outcomes over the same two periods in research track residents who participated in research training independent from and predating LEAD (research track controls and pre-LEAD research track controls). We conducted focus groups to qualitatively assess resident experiences with LEAD. Outcome: Compared to 63 pre-LEAD controls, greater proportions of 52 LEAD participants completed scientific presentations (48.1% vs. 28.6%, p = .03) and scientific presentations and peer-reviewed publications (23.1% vs. 9.5%, p = .05). No significant differences existed for any academic productivity metrics among research track controls and pre-LEAD research track controls (p > .23, all comparisons). Perceived facilitators of participation in LEAD included residents' desire for research experiences and opportunities to publish prior to fellowship training; the main barrier to participation was feeling overwhelmed due to the time constraints imposed by clinical training. Suggestions for improvement included establishing clearer programmatic expectations and providing lists of potential mentors and projects. Lessons Learned: Implementation of a multifaceted program to support scholarship during residency was associated with significant increases in academic productivity among IM residents. Residents perceived that programs to support scholarship during residency training should outline clear expectations and identify available mentors and projects for residents who are challenged by the time constraints of clinical training.
A family of 17 iron(III) aminobis(phenolate) complexes possessing different phenolate substituents, coordination geometries, and donor arrangements were used as catalysts for the reaction of carbon dioxide (CO2) with epoxides. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of the iron complexes with a bis(triphenylphosphine)iminium chloride cocatalyst in negative mode revealed the formation of six-coordinate iron "ate" species. Under low catalyst loadings (0.025 mol % Fe and 0.1 mol % chloride cocatalyst), all complexes showed good-to-excellent activity for converting propylene oxide to propylene carbonate under 20 bar of CO2. The most active complex possessed electron-withdrawing dichlorophenolate groups and for a 2 h reaction time gave a turnover frequency of 1240 h-1. Epichlorohydrin, styrene oxide, phenyl glycidyl ether, and allyl glycidyl ether could also be transformed to their respective cyclic carbonates with good-to-excellent conversions. Selectivity for polycarbonate formation was observed using cyclohexene oxide, where the best activity was displayed by trigonal-bipyramidal iron(III) complexes having electron-rich phenolate groups and sterically unencumbering tertiary amino donors. Those containing bulky tertiary amino ligands or those with square-pyramidal geometries around iron showed no activity for polycarbonate formation. While the overall conversions declined with decreasing CO2 pressure, CO2 incorporation remained high, giving a completely alternating copolymer. The difference in the optimum catalyst reactivity for cyclic carbonate versus polycarbonate formation is particularly noteworthy; that is, electron-withdrawing-group-containing phenolates give the most active catalysts for propylene carbonate formation, whereas catalysts with electron-donating-group-containing phenolates are the most active for polycyclohexene carbonate formation. This study demonstrates that the highly modifiable aminophenolate ligands can be tailored to yield iron complexes for both CO2/epoxide coupling and ring-opening copolymerization activity.
IMPORTANCE: Transient elevations of blood pressure (BP) are common in hospitalized older adults and frequently lead practitioners to prescribe more intensive antihypertensive regimens at hospital discharge than the patients were using before hospitalization.
OBJECTIVE: To investigate the association between intensification of antihypertensive regimens at hospital discharge and clinical outcomes after discharge.
DESIGN, SETTING, AND PARTICIPANTS: In this retrospective cohort study, patients 65 years and older with hypertension who were hospitalized in Veterans Health Administration national health system facilities from January 1, 2011, to December 31, 2013, for common noncardiac conditions were studied. Data analysis was performed from October 1, 2018, to March 10, 2019.
EXPOSURES: Discharge with antihypertensive intensification, defined as receiving a prescription at hospital discharge for a new or higher-dose antihypertensive than was being used before hospitalization. Propensity scores were used to construct a matched-pairs cohort of patients who did and did not receive antihypertensive intensifications at hospital discharge.
MAIN OUTCOMES AND MEASURES: The primary outcomes of hospital readmission, serious adverse events, and cardiovascular events were assessed by competing risk analysis. The secondary outcome was the change in systolic BP within 1 year of hospital discharge.
RESULTS: The propensity-matched cohort included 4056 hospitalized older adults with hypertension (mean [SD] age, 77 [8] years; 3961 men [97.7%]), equally split between those who did vs did not receive antihypertensive intensifications at hospital discharge. Groups were well matched on all baseline covariates (all standardized mean differences <0.1). Within 30 days, patients receiving intensifications had a higher risk of readmission (hazard ratio [HR], 1.23; 95% CI, 1.07-1.42; number needed to harm [NNH], 27; 95% CI, 16-76) and serious adverse events (HR, 1.41; 95% CI, 1.06-1.88; NNH, 63; 95% CI, 34-370). At 1 year, no differences were found in cardiovascular events (HR, 1.18; 95% CI, 0.99-1.40) or change in systolic BP among those who did vs did not receive intensifications (mean BP, 134.7 vs 134.4; difference-in-differences estimate, 0.6 mm Hg; 95% CI, -2.4 to 3.7 mm Hg).
CONCLUSIONS AND RELEVANCE: Among older adults hospitalized for noncardiac conditions, prescription of intensified antihypertensives at discharge was not associated with reduced cardiac events or improved BP control within 1 year but was associated with an increased risk of readmission and serious adverse events within 30 days.
The objective of the study was to (1) characterize and compare the chemical composition at the surface, subsurface and in the bulk of thin plastic films used for portosystemic shunt attenuation in their native state and after plasma exposure. (2) Assess the presence, concentration and location of irritant compounds (e.g dicetyl phosphate) within the films. Attenuated Total Reflectance Infrared Spectroscopy (ATR-IR), X-ray Photoelectron Spectroscopy (XPS) and dynamic Time-of-Flight Secondary Ion Mass Spectrometry (ToF-SIMS) were used to analyze thirteen thin plastic films. Sample thickness was visualized and measured using Scanning Electron Microscopy (SEM). Sample thicknesses were compared using a one-way ANOVA. XPS reported low phosphorous concentrations (surrogate marker of dicetyl phosphate) between 0.01 and 0.19% wt at the sample surfaces (top 10 nm). There were significant differences between film thicknesses (P < .001) observed by SEM. The ATR-IR and ToF-SIMS identified four distinct surface and bulk chemical profiles: 1) Cellophane, 2) Polypropylene, 3) Modified Cellophane, and 4) Unique. Following plasma immersion for 6 weeks, samples showed little change in film thickness or chemical composition. This study confirmed that films used to attenuate portosystemic shunts were commonly not pure cellophane, with significant variations in surface and bulk chemistry. Suspected irritant compounds were not readily identifiable in significant proportions. Pronounced variability existed in both the thickness and chemical composition of these films (surface vs. bulk). The present findings lead to a legitimate question about the reproducibility of shunt occlusion when using thin plastic films from different origins.
BACKGROUND: Patients with spinal cord injury (SCI) have a high risk for multidrug-resistant organisms, including carbapenem-resistant Enterobacteriaceae (CRE). Accurate and easily applied definitions are critical to identify CRE. This study describes CRE and associated characteristics in veterans with SCI per Centers for Disease Control and Prevention (CDC) and Department of Veterans Affairs (VA) definitions.
METHODS: A retrospective cohort of veterans with SCI and more than 1 culture with Escherichia coli, Klebsiella spp and/or Enterobacter spp between 2012 and 2013 was examined. Antibiotic susceptibility criteria of pre-2015 (CDC1) and post-2015 (CDC2) CDC definitions and pre-2017 (VA1) and post-2017 (VA2) VA definitions were used to identify CRE. CRE prevalence and characteristics are described for isolates meeting each definition, and agreement was assessed with the Cohen kappa.
RESULTS: We reviewed 21,514 isolates cultured from 6,974 veterans; 423 isolates met any CRE definition. Although agreement among definitions was high (kappa = 0.82-0.93), definitions including ertapenem resistance led to higher CRE prevalence (VA1 = 1.7% and CDC2 = 1.9% vs VA2 = 1.4% and CDC1 = 1.5%). Forty-four of 142 VA facilities had more than 1 CRE case defined by VA2; 10 facilities accounted for 60% of CRE cases. Almost all CRE was isolated from high-complexity, urban facilities, and the South had the highest proportion of CRE.
CONCLUSIONS: Varying federal definitions give different CRE frequencies in a high-risk population. Definitions including ertapenem resistance resulted in higher CRE prevalence but may overemphasize noncarbapenemase isolates. Thus, both federal definitions now highlight the importance of carbapenemase testing.