Off-target piRNA gene silencing in Drosophila melanogaster rescued by a transposable element insertion.

Transposable elements (TE) are selfish genetic elements that can cause harmful mutations. In Drosophila, it has been estimated that half of all spontaneous visible marker phenotypes are mutations caused by TE insertions. Several factors likely limit the accumulation of exponentially amplifying TEs within genomes. First, synergistic interactions between TEs that amplify their harm with increasing copy number are proposed to limit TE copy number. However, the nature of this synergy is poorly understood. Second, because of the harm posed by TEs, eukaryotes have evolved systems of small RNA-based genome defense to limit transposition. However, as in all immune systems, there is a cost of autoimmunity and small RNA-based systems that silence TEs can inadvertently silence genes flanking TE insertions. In a screen for essential meiotic genes in Drosophila melanogaster, a truncated Doc retrotransposon within a neighboring gene was found to trigger the germline silencing of ald, the Drosophila Mps1 homolog, a gene essential for proper chromosome segregation in meiosis. A subsequent screen for suppressors of this silencing identified a new insertion of a Hobo DNA transposon in the same neighboring gene. Here we describe how the original Doc insertion triggers flanking piRNA biogenesis and local gene silencing. We show that this local gene silencing occurs in cis and is dependent on deadlock, a component of the Rhino-Deadlock-Cutoff (RDC) complex, to trigger dual-strand piRNA biogenesis at TE insertions. We further show how the additional Hobo insertion leads to de-silencing by reducing flanking piRNA biogenesis triggered by the original Doc insertion. These results support a model of TE-mediated gene silencing by piRNA biogenesis in cis that depends on local determinants of transcription. This may explain complex patterns of off-target gene silencing triggered by TEs within populations and in the laboratory. It also provides a mechanism of sign epistasis among TE insertions, illuminates the complex nature of their interactions and supports a model in which off-target gene silencing shapes the evolution of the RDC complex.

Rapid fabrication of hydrophobic/hydrophilic patterns on paper substrates for paper spray mass spectrometry.

A simple, rapid chemical coating and patterning method was developed and optimized for paper-based substrates for use in paper spray mass spectrometry (PS-MS). A variety of chlorosilanes were explored for coating paper substrates, and their effectiveness in forming hydrophobic surfaces was characterized via contact angle goniometry, scanning electron microscopy, and energy dispersive X-ray spectroscopy. Trichloromethylsilane was selected as the primary coating agent because of the short time required to produce a hydrophobic surface (contact angle > 130°), as well as the ease of patterning. Patterning was performed using 3D-printed masks and an oxygen/plasma cleaner. Optimal mask thickness and oxygen/plasma cleaning parameters were determined to produce channels varying from 0.5 to 2.5 mm in width. The effectiveness of the patterned substrates for PS-MS was determined via analysis of four antiretrovirals: emtricitabine, lamivudine, efavirenz, and dolutegravir. Calibration curves were made for each antiretroviral at varying channel widths, and the limits of detection and limits of quantification for each drug were determined. These results show that this patterning method results in an average 7.2-fold improvement in sensitivity and an average 190-fold improvement in limits of detection over uncoated paper substrates in a neat matrix. In a proof-of-concept experiment, calibration curves were generated for each antiretroviral in urine. A patterned paper substrate with a 2-mm channel resulted in an average 7.4-fold improvement in sensitivity and an average 18-fold improvement in limits of detection over uncoated paper substrates.

Mass Spectroscopy Imaging of Hair Strands Captures Short-Term and Long-Term Changes in Emtricitabine Adherence.

Most measures of adherence to antiretroviral therapy require a blood sample, and none capture longitudinal daily adherence. A new noninvasive method for measuring daily adherence to antiretroviral regimens containing emtricitabine (FTC) was developed for intact hair strands using infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI). A directly observed therapy study of daily and intermittent (3, 1, and 0 doses/week) FTC dosing (n = 12) benchmarked adherence in hair, revealing distinct accumulation patterns and median FTC signal abundance (1,702, 495, 352, and 0, respectively) with each dosing frequency. A threshold value of FTCsignal abundance of 500 differentiated daily dosing from 3 or fewer doses/week (specificity, 100%; sensitivity, 100% over 30 days and 80% over 60 days). Using these criteria, daily FTC hair adherence was classified in young men (n = 8) who have sex with men (YMSM) engaged in or initiating preexposure prophylaxis (PrEP). Four types of adherence profiles were observed in sequential 30-day periods: consistently high, occasional missed doses, improvement following study initiation, and intermittent. Discrete days of nonadherence were identified across the 60-day window, with the average number of consecutive days classified as nonadherent increasing across the four profile types (1, 2, 19, and 58 days, respectively). Additionally, cumulative FTC response in hair (60-day average) significantly correlated with dried blood spot tenofovir diphosphate concentrations collected simultaneously (rs = 0.79, P = 0.03). Based on these data, IR-MALDESI FTC adherence classification in hair strands can better delineate short-term changes in adherence behaviors over a long retrospective window, offering great potential for noninvasive adherence monitoring and quick supportive interventions.

Influence of hair treatments on detection of antiretrovirals by mass spectrometry imaging.

Analysis of drugs in hair by mass spectrometry imaging (MSI) has great potential as an objective, long-term measure of medication adherence. However, the fidelity of the chemical record in hair may be compromised by any cosmetic hair treatments. Here, we investigate infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) MSI response to multiple antiretrovirals (ARVs) in cosmetically treated hair. Hair strands from patients on different ARV regimens were mechanically treated with dye, bleach, and relaxer. The treatments had little or no effect relative to untreated controls for cobicistat, abacavir, dolutegravir, maraviroc, efavirenz, and darunavir, but all three treatments removed emtricitabine (FTC) to undetectable levels from patient hair strands. We also evaluated hair strands by IR-MALDESI MSI from 8 patients on FTC-based regimens who reported a range of hair treatments at varying recency prior to hair collection. While FTC was undetectable in the treated portion of these hair strands, ARVs coadministered with FTC remained detectable in hair strands after treatment. We conclude that IR-MALDESI MSI can be used when measuring adherence to ARV therapy, provided that ARVs other than FTC are targeted in people using hair treatments.

It's a matter of trust: exploring the basis of program directors' decisions about whether to trust a resident to care for a loved one.

There has been increased attention to and emphasis on competency-based medical education and the transformation from highly supervised medical students towards independent, entrustable physicians. We explored how program directors (PDs) justify decisions about whether they would trust finishing Post Graduate Year 1 (PGY1) residents to care for the PD or a loved one. Using an end of year survey with validity evidence, we assessed PDs' responses (Yes, No, Not Sure) and written comments about this entrustment decision for USUHS medical students from graduating classes of 2013-2015 (PGY1). We performed a qualitative inductive content analysis to identify themes in how PDs justified their decisions as well as descriptive statistics and a contingency table analysis to examine associations between trust decisions and election to membership in Alpha Omega Alpha (AOA), or conversely, referral to the Student Promotions Committee (SPC) for remediation. Qualitative analyses revealed five themes related to this trust decision about medical residents: personal, interpersonal, knowledge, competence, and developmental. Neither AOA status, nor SPC referral status was significantly associated with the trust measure, overall, but positive trust decisions were significantly higher among those elected to AOA than in those who were not. Positive trust decisions were significantly associated with AOA status but negative trust decisions were not significantly associated with referral to the SPC. This study offers insights into what attributes may underpin trust decisions by PDs. Our findings suggest that PDs' frequent use of personal and interpersonal characteristics to justify trust decisions contrasts with the use of clinical and knowledge based assessments during undergraduate medical education (UME), and emphasize the importance of critical intrinsic abilities.

Infrared Matrix-Assisted Laser Desorption Electrospray Ionization Mass Spectrometry Imaging of Human Hair to Characterize Longitudinal Profiles of the Antiretroviral Maraviroc for Adherence Monitoring.

Here, we assess infrared matrix assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) analysis of hair as a clinical tool for monitoring patient adherence to the antiretroviral maraviroc (MVC). A custom MATLAB-based algorithm has been developed to streamline data analysis and generate longitudinal profiles of drug incorporation along the length of hair strands. Hair strands from volunteers enrolled in a directly observed therapy study were analyzed by IR-MALDESI MSI and processed using this tool to characterize the profiles of single doses and a daily dose regimen of MVC. Single dose responses were 1.7 [1.1, 2.5] mm (median [range]) wide along the length of the hair and were detected in 8 out of 12 volunteers. Daily dose profiles capturing 28 days of continuous dosing were approximately 5 times the intensity of single dose profiles and 10.5 [7.0, 13] mm wide, corresponding to 1 month of hair growth. MVC ion abundance was observed in all 12 volunteers for the daily dosing period. Daily dosing profiles were consistent with a model of MVC accumulation in hair based on linear superposition of a single dose response, indicating the potential for prediction of daily drug-taking behavior based on deconvolution of a complex longitudinal profile in hair.

Antiretroviral concentrations and surrogate measures of efficacy in the brain tissue and CSF of preclinical species.

1. Antiretroviral concentrations in cerebrospinal fluid (CSF) are used as surrogate for brain tissue, although sparse data support this. We quantified antiretrovirals in brain tissue across preclinical models, compared them to CSF, and calculated 90% inhibitory quotients (IQ90) for nonhuman primate (NHP) brain tissue. Spatial distribution of efavirenz was performed by mass-spectrometry imaging (MSI). 2. HIV or RT-SHIV-infected and uninfected animals from two humanized mouse models (hemopoietic-stem cell/RAG2-, n = 36; bone marrow-liver-thymus/BLT, n =13) and an NHP model (rhesus macaque, n =18) were dosed with six antiretrovirals. Brain tissue, CSF (NHPs), and plasma were collected at necropsy. Drug concentrations were measured by LC-MS/MS. Rapid equilibrium dialysis determined protein binding in NHP brain. 3. Brain tissue penetration of most antiretrovirals were >10-fold lower (p < 0.02) in humanized mice than NHPs. NHP CSF concentrations were >13-fold lower (p <0.02) than brain tissue with poor agreement except for efavirenz (r = 0.91, p = 0.001). Despite 97% brain tissue protein binding, efavirenz achieved IQ90>1 in all animals and 2-fold greater white versus gray matter concentration. 4. Brain tissue penetration varied across animal models for all antiretrovirals except raltegravir, and extrapolating brain tissue concentrations between models should be avoided. With the exception of efavirenz, CSF is not a surrogate for brain tissue concentrations.

Post-Carnegie II curricular reform: a north American survey of emerging trends & challenges.

BACKGROUND: In 2010, coincident with the 100th anniversary of Flexner's sentinel report, the Carnegie Foundation published an updated review of North American medical education and challenged medical schools to initiate further educational reforms. Specific recommendations pertained to a) ensuring standardized outcomes while allowing for individualized processes, b) integrating foundational knowledge with clinical experience, c) cultivating habits of inquiry and innovation and d) professional identity formation. As we approach the 10-year anniversary of this latest report, we sought to determine what type of curricular revisions have been emerging within the past decade and what types of challenges have been encountered along the way? METHODS: In 2018, an electronic survey was sent to all 166 Liaison Committee on Medical Education (LCME) accredited North American Medical Schools, using the points of contact (educational deans) that were listed in a publicly available, Association of American Medical Colleges database. Free text comments were grouped into themes using the constant-comparative technique. RESULTS: Sixty unique responses yielding a 36.14% response rate. The distribution of responses was proportionally representative of the distribution of public vs. private, old vs. new vs. established North American medical schools. Self-reported curricular changes aggregated into five main themes: Changes in curricular structure/organization, changes in curricular content, changes in curricular delivery, changes in assessment, and changes involving increased use of technology/informatics. Challenges were predominantly focused on overcoming faculty resistance, faculty development, securing adequate resourcing, change management, and competition for limited amounts of curricular time. CONCLUSIONS: Changes in curricular organization, content, delivery, assessment and the use of technology reflect reforms that are broad and deep. Empowering faculty to "let go" of familiar constructs/processes requires strong leadership, particularly when initiating particularly disruptive curricular changes, such as relocating the Step 1 examination or shifting to a competency-based curriculum. While North American medical schools are responding to the calls for action described in the second (2010) Carnegie Foundation report, the full vision has yet to be achieved.

Combination of anti-citrullinated protein antibodies and rheumatoid factor is associated with increased systemic inflammatory mediators and more rapid progression from preclinical to clinical rheumatoid arthritis.

The development of rheumatoid factor (RF) and/or anti-citrullinated protein antibodies (ACPAs) can be observed years prior to clinical diagnosis of rheumatoid arthritis (RA). Nevertheless, the interaction between these two autoantibodies and their combined effect on development of RA is unclear. We measured RF, cytokines, and ACPA subtypes in serial pre-clinical serum samples collected from 83 US veterans who all developed RA. Levels of cytokines and ACPAs were compared between the following groups: anti-cyclic citrullinated peptide (anti-CCP)-/RF- (double negative), anti-CCP+/RF-, anti-CCP-/RF+, or anti-CCP+/RF+ (double-positive). The double-positive subgroup had significantly higher levels of 20 inflammatory cytokines and 29 ACPA reactivities, and the shortest interval, 1.3 years, between the preclinical sample timepoint and diagnosis of RA. Thus, the combined presence of ACPAs and RF is associated with a more rapid progression to RA, suggesting that anti-CCP+/RF+ individuals have a more advanced preclinical disease state and that the onset of RA may be imminent.

Development of a Microchip CE-HPMS Platform for Cell Growth Monitoring.

Improvements were made to a previously developed platform coupling microchip capillary electrophoresis (CE) with high pressure mass spectrometry (HPMS). The RF drive frequency was increased to over 30 MHz from less than 10 MHz, and the ion trap was scaled down to 100 µm critical dimensions. A stretched length ion trap was used to improve sensitivity, and a tube lens was used to improve ion transmission. Detection of the 20 common amino acids was demonstrated, resulting in an average improvement of signal-to-noise of 28 times and an average improvement in peak width of 2.6 times over those obtained in previous work. Consumption of amino acids by cells in growth media was monitored over time using the improved CE-HPMS platform, and several amino acids were shown to be consumed at different rates, demonstrating the potential for real-time bioreactor monitoring.

Coupling Microchip Electrospray Ionization Devices with High Pressure Mass Spectrometry.

A microchip electrospray ionization source was coupled with high pressure mass spectrometry (HPMS). A continuous atmospheric inlet consisting of a stainless steel capillary and DC ion optics was designed to conduct ions into the mass spectrometer. Infusions of amino acids and peptides were performed and detected with a miniature cylindrical ion trap (mini-CIT)-based mass spectrometer operated at ≥1 Torr with air as the buffer gas. Detection of glycine and thymopentin (separately) demonstrated the mass range of the mini-CIT detector could span from m/z 75 to 681. A microchip capillary electrophoresis (CE) separation with mini-CIT detection was performed, and the results were compared with detection using a commercial instrument (Waters Synapt G2). Comparable separation efficiencies were observed with both mass spectrometers as detectors, with about 6 times better signal-to-noise observed on the Synapt G2. Comparison of mass spectra in the two systems reveals similar features observed, but with wider peak widths in the mini-CIT than on the Synapt G2 as expected due to high-pressure operation.

High pressure mass spectrometry of volatile organic compounds with ambient air buffer gas.

RATIONALE: There are many chemical measurement scenarios that would benefit from hand portable mass spectrometry tools including forensics, environmental monitoring, and safety and security. High pressure mass spectrometry (HPMS) facilitates miniaturization by significantly reducing vacuum system requirements. Previous work demonstrated HPMS using helium buffer gas, but HPMS conducted using ambient air would further reduce the size and weight of a portable instrument while also reducing logistical demands by eliminating the need for a helium supply. METHODS: Mass spectrometry was performed at pressures exceeding 1 Torr with ambient air as the buffer gas. A glow discharge electron ionization source and a miniature cylindrical ion trap mass analyzer with a radius of 0.5 mm were used. Mass analysis was possible at these pressures with increased radiofrequency (RF) drive frequencies (10 MHz) compared with commercial ion traps (~1 MHz). A differentially pumped chamber was used so that mass spectrometry could be performed at high pressures and detection performed at low pressures with an electron multiplier. RESULTS: HPMS with air buffer gas was demonstrated using a suite of volatile organic compounds (VOCs). The glow discharge ionization source was optimized for operation using air. Mass spectral peak widths increased a factor of 8 compared with helium, as expected, but useful chemical information was still acquired. A mixture of VOCs was detected with ambient air as the buffer gas, showing that valuable mass information can be gained using HPMS without the requirement of an onboard buffer gas source. CONCLUSIONS: HPMS significantly reduces the pumping requirements required for miniature mass spectrometers and the use of ambient air buffer gas further reduces size, weight, and logistics requirements. Mass analysis at high pressures of ambient air is another important step for the development of hand portable mass spectrometers. Copyright © 2016 John Wiley & Sons, Ltd.

Performance of anti-cyclic citrullinated Peptide assays differs in subjects at increased risk of rheumatoid arthritis and subjects with established disease.

OBJECTIVE: To compare the diagnostic accuracy and agreement of commonly available assays for anti-citrullinated protein antibodies in patients with established rheumatoid arthritis (RA) and subjects at increased risk of RA. METHODS: Tests for anti-cyclic citrullinated peptide (anti-CCP) antibodies were performed using CCP2 IgG and CCP3.1 IgA/IgG enzyme-linked immunosorbent assays in the following groups: probands with established RA (n = 340) from the Studies of the Etiology of Rheumatoid Arthritis (SERA) cohort and their first-degree relatives (FDRs) without inflammatory arthritis (n = 681), Department of Defense Serum Repository (DoDSR) RA cases with pre-RA diagnosis samples (n = 83; 47 cases also had post-RA diagnosis samples), and blood donor and DoDSR control subjects (n = 283). RESULTS: In patients with established RA, the CCP2 assay was more specific (99.2% versus 93.1%; P < 0.01) but less sensitive (58.7% versus 67.4%; P = 0.01) than the CCP3.1 assay; the specificity of the CCP3.1 assay increased to 97.2% when cutoff levels ≥3-fold the standard level were considered. In all subjects, CCP3.1 assay positivity (using standard cutoff levels) was more prevalent. Among DoDSR cases, the CCP2 assay was more specific than the CCP3.1 for predicting a future diagnosis of RA, and higher CCP levels trended toward increasing specificity for the development of RA within 2 years. At standard cutoff levels, assay agreement was good in patients with established RA (κ = 0.76) but poor in FDRs without inflammatory arthritis (κ = 0.25). CONCLUSION: Anti-CCP assays differ to an extent that may be meaningful for diagnosing RA in patients with inflammatory arthritis and evaluating the natural history of RA development in subjects at risk of RA. The mechanisms underlying these differences in test performance need further investigation.

Validity evidence for medical school OSCEs: associations with USMLE® step assessments.

BACKGROUND: Recently, there has been a surge in the use of objective structured clinical examinations (OSCEs) at medical schools around the world, and with this growth has come the concomitant need to validate such assessments. PURPOSES: The current study examined the associations between student performance on several school-level clinical skills and knowledge assessments, including two OSCEs, the National Board of Medical Examiners® (NBME) Subject Examinations, and the United States Medical Licensing Examination® (USMLE) Step 2 Clinical Skills (CS) and Step 3 assessments. METHODS: The sample consisted of 806 medical students from the Uniformed Services University of the Health Sciences. We conducted Pearson correlation analysis as well as stepwise multiple linear regression modeling to examine the strength of associations between students' performance on 2nd- and 3rd-year OSCEs and their two Step 2 CS component scores and Step 3 scores. RESULTS: Positive associations were found between the OSCE variables and the USMLE scores; in particular, student performance on both the 2nd- and 3rd-year OSCEs was more strongly associated with the two Step 2 CS component scores than with Step 3 scores. CONCLUSIONS: These findings, although preliminary, provide some predictive validity evidence for the use of OSCEs in determining readiness of medical students for clinical practice and licensure.

A Cytological F1 RNAi Screen for Defects in Drosophila melanogaster Female Meiosis.

Genetic screens for recessive alleles induce mutations, make the mutated chromosomes homozygous, and then assay those homozygotes for the phenotype of interest. When screening for genes required for female meiosis, the phenotype of interest has typically been nondisjunction from chromosome segregation errors. As this requires that mutant females be viable and fertile, any mutants that are lethal or sterile when homozygous cannot be recovered by this approach. To overcome these limitations, our lab has screened the VALIUM22 collection produced by the Harvard TRiP Project, which contains RNAi constructs targeting genes known to be expressed in the germline in a vector optimized for germline expression. By driving RNAi with GAL4 under control of a germline-specific promoter (nanos or mat-alpha4), we can test genes that would be lethal if knocked down in all cells, and by examining unfertilized metaphase-arrested mature oocytes, we can identify defects associated with genes whose knockdown results in sterility or causes other errors besides nondisjunction. We screened this collection to identify genes that disrupt either of two phenotypes when knocked down: the ability of meiotic chromosomes to congress to a single mass at the end of prometaphase, and the sequestration of Mps1-GFP to ooplasmic filaments in response to hypoxia. After screening >1450 lines of the collection, we obtained multiple hits for both phenotypes, identified novel meiotic phenotypes for genes that had been previously characterized in other processes, and identified the first phenotypes to be associated with several previously uncharacterized genes.

A cytological F1 RNAi screen for defects in Drosophila melanogaster female meiosis.

Genetic screens for recessive alleles induce mutations, make the mutated chromosomes homozygous, and then assay those homozygotes for the phenotype of interest. When screening for genes required for female meiosis, the phenotype of interest has typically been nondisjunction from chromosome segregation errors. As this requires that mutant females be viable and fertile, any mutants that are lethal or sterile when homozygous cannot be recovered by this approach. To overcome these limitations, we have screened the VALIUM22 collection of RNAi constructs that target germline-expressing genes in a vector optimized for germline expression by driving RNAi with GAL4 under control of a germline-specific promoter (nanos or mat-alpha4). This allowed us to test genes that would be lethal if knocked down in all cells, and by examining unfertilized metaphase-arrested mature oocytes, we could identify defects in sterile females. After screening >1,450 lines of the collection for two different defects (chromosome congression and the hypoxic sequestration of Mps1-GFP to ooplasmic filaments), we obtained multiple hits for both phenotypes, identified novel meiotic phenotypes for genes that had been previously characterized in other processes, and identified the first phenotypes to be associated with several previously uncharacterized genes.

Application essays and future performance in medical school: are they related?

BACKGROUND: There is a paucity of research on whether application essays are a valid indicator of medical students' future performance. PURPOSE: The goal is to score medical school application essays systematically and examine the correlations between these essay scores and several indicators of student performance during medical school and internship. METHODS: A journalist created a scoring rubric based on the journalism literature and scored 2 required essays of students admitted to our university in 1 year (N = 145). We picked 7 indicators of medical school and internship performance and correlated these measures with overall essay scores: preclinical medical school grade point average (GPA), clinical medical school GPA, cumulative medical school GPA, U.S. Medical Licensing Exam (USMLE) Step 1 and 2 scores, and scores on a program director's evaluation measuring intern professionalism and expertise. We then examined the Pearson and Spearman correlations between essay scores and the outcomes. RESULTS: Essay scores did not vary widely. American Medical College Application Service essay scores ranged from 3.3 to 4.5 (M = 4.11, SD = 0.15), and Uniformed Services University of the Health Sciences essay scores ranged from 2.9 to 4.5 (M = 4.09, SD = 0.17). None of the medical school or internship performance indicators was significantly correlated with the essay scores. CONCLUSIONS: These findings raise questions about the utility of matriculation essays, a resource-intensive admission requirement.

Lineage-based scaling of germline intercellular bridges during oogenesis.

The size of subcellular structures must be tightly controlled to maintain normal cell function; this is especially important when cells are part of developing tissues or organs. Despite its importance, few studies have determined how the size of organelles or other structures is maintained during tissue growth, when cells are growing, dividing, and rearranging. The developing egg chamber is a powerful model in which to study the relative growth rates of subcellular structures. The egg chamber contains a cluster of sixteen germ cells, which are connected through intercellular bridges called ring canals. Ring canals are formed following incomplete cytokinesis after each of four germ cell divisions. As the egg chamber grows, the nurse cells and the ring canals that connect them increase in size. Here, we demonstrate that ring canal size scaling is related to their lineage; the largest, "first born" ring canals grow at a relatively slower rate than ring canals derived from subsequent mitotic divisions. This lineage-based scaling relationship is maintained even if directed transport is reduced, ring canal size is altered, or if the germ cells go through an additional mitotic division. Further, we propose that changes in ring canal scaling could provide a mechanism to alter egg size.

Mass spectrometry imaging of hair identifies daily maraviroc adherence in HPTN 069/ACTG A5305.

Objective measures of adherence for antiretrovirals used as pre-exposure prophylaxis (PrEP) are critical for improving preventative efficacy in both clinical trials and real-world application. Current objective adherence measures either reflect only recent behavior (eg days for plasma or urine) or cumulative behavior (eg months for dried blood spots). Here, we measured the accumulation of the antiretroviral drug maraviroc (MVC) in hair strands by infrared matrix-assisted laser desorption electrospray ionization (IR-MALDESI) mass spectrometry imaging (MSI) to evaluate adherence behavior longitudinally at high temporal resolution. An MSI threshold for classifying daily adherence was established using clinical samples from healthy volunteers following directly observed dosing of 1 to 7 doses MVC/week. We then used the benchmarked MSI assay to classify adherence to MVC-based PrEP regimens in hair samples collected throughout the 48-week HPTN069/ACTGA5305 study. We found that only ~32% of investigated hair samples collected during the study's active dosing period showed consistent daily PrEP adherence throughout a retrospective period of 30 days, and also found that profiles of daily individual adherence from MSI hair analysis could identify when patients were and were not taking study drug. The assessment of adherence from MSI hair strand analysis was 62% lower than adherence classified using paired plasma samples, the latter of which may be influenced by white-coat adherence. These findings demonstrate the ability of MSI hair analysis to examine daily variability of adherence behavior over a longer-term measurement and offer the potential for longitudinal comparison with risk behavior to target patient-specific adherence interventions and improve outcomes.

Does self-reported clinical experience predict performance in medical school and internship?

CONTEXT: Medical school admissions committees attempt to select the most qualified applicants. In addition to traditional performance measures, committees often look favourably upon applicants who report previous clinical experience. OBJECTIVES: This study aimed to determine if self-reported clinical experience is a valid indicator of future performance in medical school and internship. METHODS: We collected data for seven year groups (1993-1999; n = 1112) and operationalised trainee performance in terms of five outcomes: cumulative medical school grade point average (GPA); US Medical Licensing Examination (USMLE) Step 1 and 2 scores, and scores on a validated programme director's evaluation measuring intern expertise and professionalism. We then conducted a series of analyses of covariance to compare outcomes in applicants who self-reported previous clinical experience with outcomes in those who did not. In these analyses, the independent variable was self-reported clinical experience (yes/no), the covariate was undergraduate GPA, and the dependent variables were the five performance outcomes. RESULTS: In four of five analyses, we found no differences in the performance of the two groups (clinical experience versus no clinical experience). However, on the cumulative medical school GPA outcome, applicants who reported previous clinical experience had statistically significantly lower cumulative GPAs upon graduation than those who did not report such experience (F(1,940) = 9.35, p = 0.002, partial η(2) = 0.01 [small effect size]). CONCLUSIONS: Our results suggest that applicants who self-report previous clinical experience may not be better candidates. In fact, on some measures of performance, these applicants may actually perform worse than those who report no clinical experience.