Development of anti-aflatoxin B1 nanobodies from a novel mutagenesis-derived synthetic library for traditional Chinese medicine and foods safety testing.

BACKGROUND: The main commercially available methods for detecting small molecules of mycotoxins in traditional Chinese medicine (TCM) and functional foods are enzyme-linked immunosorbent assay and mass spectrometry. Regarding the development of diagnostic antibody reagents, effective methods for the rapid preparation of specific monoclonal antibodies are inadequate. METHODS: In this study, a novel synthetic phage-displayed nanobody Golden Glove (SynaGG) library with a glove-like cavity configuration was established using phage display technology in synthetic biology. We applied this unique SynaGG library on the small molecule aflatoxin B1 (AFB1), which has strong hepatotoxicity, to isolate specific nanobodies with high affinity for AFB1. RESULT: These nanobodies exhibit no cross-reactivity with the hapten methotrexate, which is recognized by the original antibody template. By binding to AFB1, two nanobodies can neutralize AFB1-induced hepatocyte growth inhibition. Using molecular docking, we found that the unique non-hypervariable complementarity-determining region 4 (CDR4) loop region of the nanobody was involved in the interaction with AFB1. Specifically, the CDR4's positively charged amino acid arginine directed the binding interaction between the nanobody and AFB1. We then rationally optimized the interaction between AFB1 and the nanobody by mutating serine at position 2 into valine. The binding affinity of the nanobody to AFB1 was effectively improved, and this result supported the use of molecular structure simulation for antibody optimization. CONCLUSION: In summary, this study revealed that the novel SynaGG library, which was constructed through computer-aided design, can be used to isolate nanobodies that specifically bind to small molecules. The results of this study could facilitate the development of nanobody materials to detect small molecules for the rapid screening of TCM materials and foods in the future.

A Concordance Study of COMLEX-USA and USMLE Scores.

BACKGROUND: Under the single GME accreditation system, residency programs receive applicants from MD- and DO-granting medical schools, each of which have their own set of licensing examinations, making concordance studies increasingly relevant. Previous studies comparing Comprehensive Osteopathic Medical Licensing Examination of the United States (COMLEX-USA) and United States Medical Licensing Examination (USMLE) scores have been limited in sample size and examinee composition and have yielded comparisons that may not be generalizable across all applicants. Some osteopathic medical students take USMLE in addition to COMLEX-USA, often at considerable cost and effort, with the aim of making themselves more desirable to potential residency programs. Having more reliable comparisons of COMLEX-USA and USMLE scores would allow program directors to better estimate a score on the alternate examination. OBJECTIVE: To derive an accurate concordance between COMLEX-USA and USMLE scores, based on a large sample of osteopathic students who took both examinations. METHODS: Five colleges of osteopathic medicine, representing various regions of the United States, participated in this study. The data included demographics and COMLEX-USA and USMLE scores from September 2015 through August 2020 for students who took both examinations. We derived the concordance between COMLEX-USA and USMLE scores using equipercentile matching. RESULTS: Comparisons of demographic characteristics showed only minor differences between the sample and the overall population for COMLEX-USA takers, although scores for the study sample were, on average, greater. CONCLUSIONS: A strong association exists between the scores on the COMLEX-USA and USMLE examinations, allowing prediction of performance on USMLE from COMLEX-USA.

Examining concurrent validity between COMLEX-USA Level 2-Cognitive Evaluation and COMLEX-USA Level 2-Performance Evaluation.

CONTEXT: The Comprehensive Osteopathic Medical Licensing Examination of the United States of America (COMLEX-USA) is a three level examination used as a pathway to licensure for students in osteopathic medical education programs. COMLEX-USA Level 2 includes a written assessment of Fundamental Clinical Sciences for Osteopathic Medical Practice (Level 2-Cognitive Evaluation [L2-CE]) delivered in a computer based format and separate performance evaluation (Level 2-Performance Evaluation [L2-PE]) administered through live encounters with standardized patients. L2-PE was designed to augment L2-CE. It is expected that the two examinations measure related yet distinct constructs. OBJECTIVES: To explore the concurrent validity of L2-CE with L2-PE. METHODS: First attempt test scores were obtained from the National Board of Osteopathic Medical Examiners database for 6,639 candidates who took L2-CE between June 2019 and May 2020 and matched to the students' L2-PE scores. The sample represented all colleges of osteopathic medicine and 97.5% of candidates who took L2-CE during the complete 2019-2020 test cycle. We calculated disattenuated correlations between the total score for L2-CE, the L2-CE scores for the seven competency domains (CD1 through CD7), and the L2-PE scores for the Humanistic Domain (HM) and Biomedical/Biomechanical Domain (BM). All scores were on continuous scales. RESULTS: Pearson correlations ranged from 0.10 to 0.88 and were all statically significant (p<0.01). L2-CE total score was most strongly correlated with CD2 (0.88) and CD3 (0.85). Pearson correlations between the L2-CE competency domain subscores ranged from 0.17 to 0.70, and correlations which included either HM or BM ranged from 0.10 to 0.34 with the strongest of those correlations being between BM and L2-CE total score (0.34) as well as between HM and BM (0.28).The largest increase between corresponding Pearson and disattenuated correlations was for pairs of scores with lower reliabilities such as CD5 and CD6, which had a Pearson correlation of 0.17 and a disattenuated correlation of 0.68. The smallest increase in correlations was observed in pairs of scores with larger reliabilities such as L2-CE total score and HM, which had a Pearson correlation of 0.23 and a disattenuated correlation of 0.28. The reliability of L2-CE was 0.87, 0.81 for HM, and 0.73 for BM. The reliabilities for the L2-CE competency domain scores ranged from 0.22 to 0.74. The small to moderate correlations between the L2-CE total score and the two L2-PE support the expectation that these examinations measure related but distinct constructs. The correlations between L2-PE and L2-CE competency domain subscores reflect the distribution of items defined by the L2-PE blueprint, providing evidence that the examinations are performing as designed. CONCLUSIONS: This study provides evidence supporting the validity of the blueprints for constructing COMLEX-USA Levels 2-CE and 2-PE examinations in concert with the purpose and nature of the examinations.

Meaningful use of COMSAE Phase 1 in preparation for COMLEX-USA Level 1.

CONTEXT: The Comprehensive Osteopathic Medical Licensing Examination of the United States (COMLEX-USA) is a three level national standardized licensure examination for the practice of osteopathic medicine. The Comprehensive Medical Self Assessment Examination (COMSAE) is a three phase self assessment tool designed to gauge the base knowledge and ability of candidates preparing for COMLEX-USA. OBJECTIVES: To investigate how COMSAE Phase 1 (Phase 1) was used by candidates and how completing Phase 1 impacted their performance on the COMLEX-USA Level 1 (Level 1) examination. METHODS: Using data from the 2018-2019 administration of Level 1 and Phase 1 examinations, we counted the frequency of the unique Phase 1 forms taken by the candidates and calculated the correlation between the candidates' first attempt Phase 1 scores and the number of Phase 1 forms taken. We then calculated the correlation between the Level 1 scores and the Phase 1 scores. Next, we applied a multilevel regression model to examine the candidates' score improvement on the multiple Phase 1 forms taken. Finally, we investigated the effect of practicing through Phase 1 on the candidates' Level 1 performance using logistic regression models. RESULTS: The majority of candidates took one (2,414; 33.9%) to two (2,196; 30.8%) timed Phase 1 forms prior to the Level 1 examination. There was a significant negative correlation (r=-0.48, t(6,505)=-44.05, p<0.001) between the candidates' first attempt Phase 1 scores and the number of Phase 1 forms taken. There was a strong and positive correlation (r=0.66 to 0.74, p<0.001) between Phase 1 and Level 1 scores. With other variables controlled, on average, candidates' Phase 1 scores increased 23.2 points on one attempt from the previous attempt. Having the most recent Phase 1 score controlled, a greater number of Phase 1 forms taken was associated with an improvement on the Level 1 performance. CONCLUSIONS: The significant correlation between Phase 1 and Level 1 performance provided validity evidence for Phase 1. Moreover, our results suggested that candidates, especially those with lower performance on their initial Phase 1 attempt, might improve their Level 1 performance by taking multiple Phase 1 forms to monitor their academic improvement and gauge their readiness for Level 1.

CATALYST: Piloting a Longitudinal Assessment and Learning Program for Board Recertification and Continuous Professional Development.

Context: As a proposed alternative to the traditional recertification examination, CATALYST is a longitudinal formative assessment platform created on cognitive learning principles. CATALYST was designed by the National Board of Osteopathic Medical Examiners to encourage more complex and durable practice-relevant learning and demonstration of ongoing competencies. Objective: To investigate the value of the CATALYST platform using board diplomates' subjective feedback and comparison of performance on CATALYST questions with performance on board examinations. Methods: Diplomates from 3 osteopathic specialty boards (the American Osteopathic Board of Internal Medicine, the American Osteopathic Board of Pediatrics, and the American Osteopathic Board of Obstetricians and Gynecologists) participated in this pilot study. Over the course of 16 weeks, participants were provided 2 questions per week via the CATALYST platform. An evaluation survey was emailed at the end of the study period to collect participants' feedback. Survey results and correlations of CATALYST performance with past or upcoming board examination scores were analyzed. Results: A total of 196 diplomates completed the surveys, with 95% reporting that participation in the platform would help them stay current in their specialties and 91% reporting that participation would help them provide better care to their patients. For the AOBIM, a significant correlation was found between the number of CATALYST questions answered correctly and performance on the board examination (r=0.51, P<.001). The correlations found for the AOBP and AOBOG were not significant (r=0.197, P=.296, and r=0.370, P=.075, respectively). Conclusion: The CATALYST platform could offer valuable contributions to the board recertification process and to patient safety. Further investigations are being conducted on a new user-friendly platform.

A Validity Study of COMLEX-USA Level 2-CE and COMAT Clinical Subjects: Concurrent and Predictive Evidence.

BACKGROUND: The Comprehensive Osteopathic Medical Licensure Examination (COMLEX-USA) Level 2-Cognitive Examination (CE) and the Comprehensive Osteopathic Medical Achievement Test (COMAT) are administered to similar populations (third- and fourth-year osteopathic students) at similar points in time. Examining the relationship between scores on the 2 assessments that measure similar constructs ultimately supports the validity of both. OBJECTIVE: The purpose of this study is to provide empirical evidence of the concurrent and predictive validity of COMAT and COMLEX-USA Level 2-CE. METHODS: In 2018, first-attempt scores on Level 2-CE were aggregated from June 2015 to May 2018 and matched with first-attempt scores on each COMAT clinical subject. We conducted correlational analyses between performance on COMAT and Level 2-CE, and COMAT scores and Level 2-CE discipline subscores. Additionally, we used multivariate regression to analyze the predictive relationship between performance on all COMAT clinical subjects and Level 2-CE. RESULTS: The results from correlational analyses indicated statistically significant, positive associations between COMAT and Level 2-CE scores (r = 0.49-0.68, P < .0001), and statistically significant, but slightly weaker relationships between COMAT scores and Level 2-CE discipline subscores (r = 0.31-0.60, P < .0001). Furthermore, results from the multiple regression indicated that scores on COMAT explained 68% of the variance in Level 2-CE scores, and that COMAT internal medicine and emergency medicine were weighted more heavily than other specialties. CONCLUSIONS: The findings from this study can inform assessment practices by supporting the use of COMAT for osteopathic medical schools that do not administer COMAT.