Donor-Derived Mycoplasma and Ureaplasma Infections in Lung Transplant Recipients: A Prospective Study of Donor and Recipient Respiratory Tract Screening and Recipient Outcomes.

Mycoplasma hominis and Ureaplasma species are urogenital mollicutes that can cause serious donor-derived infections in lung transplant recipients. Best practices for mollicute screening remain unknown. We conducted a single center prospective study analyzing lung transplants performed from 10/5/20 - 9/5/21 whereby donor and recipient bronchoalveolar lavage (BAL) samples obtained at time of transplant underwent mollicute screening via culture and polymerase chain reaction (PCR). Of 115 total lung transplants performed, 99 (86%) donors underwent combined mollicute BAL culture and PCR testing. The study cohort included these 99 donors and their matched recipients. In total, 18 (18%) of 99 donors screened positive via culture or PCR. Among recipients, 92 (93%) of 99 had perioperative BAL screening performed, and only 3 (3%) had positive results. After transplant, 9 (9%) recipients developed mollicute infection. Sensitivity of donor screening in predicting recipient mollicute infection was 67% (6/9) via culture and 56% (5/9) via PCR. Positive predictive value (PPV) for donor culture was 75% (6/8), compared to 33% (5/15) for PCR. Donor screening via culture predicted all serious recipient mollicute infections and had better PPV than PCR; however, neither screening test predicted all mollicute infections. Independent of screening results, clinicians should remain suspicious for post-transplant mollicute infection.

Microsatellite Instability Testing and Prognostic Implications in Colorectal Cancer.

Given the crucial predictive implications of microsatellite instability (MSI) in colorectal cancer (CRC), MSI screening is commonly performed in those with and at risk for CRC. Here, we compared results from immunohistochemistry (IHC) and the droplet digital PCR (ddPCR) MSI assay on formalin-fixed paraffin-embedded tumor samples from 48 patients who underwent surgery for colon and rectal cancer by calculating Cohen's kappa measurement (k), revealing high agreement between the methods (k = 0.915). We performed Kaplan-Meier survival analyses and univariate and multivariate Cox regression to assess the prognostic significance of ddPCR-based MSI and to identify clinicopathological features associated with CRC outcome. Patients with MSI-high had better overall survival (OS; p = 0.038) and disease-free survival (DFS; p = 0.049) than those with microsatellite stability (MSS). When stratified by primary tumor location, right-sided CRC patients with MSI-high showed improved DFS, relative to those with MSS (p < 0.001), but left-sided CRC patients did not. In multivariate analyses, MSI-high was associated with improved OS (hazard ratio (HR) = 0.221, 95% confidence interval (CI): 0.026-0.870, p = 0.042), whereas the loss of DNA mismatch repair protein MutL homolog 1 (MLH1) expression was associated with worse OS (HR = 0.133, 95% CI: 0.001-1.152, p = 0.049). Our results suggest ddPCR is a promising tool for MSI detection. Given the opposing effects of MSI-high and MLH1 loss on OS, both ddPCR and IHC may be complementary for the prognostic assessment of CRC.

Temporary Stabilization of Tibia Fractures: Does External Fixation or Temporary Plate Fixation Result in Better Outcomes?

Background: Provisional stabilization of high-energy tibia fractures using temporary plate fixation (TPF) or external fixation (ex-fix) prior to definitive medullary nailing (MN) is a strategy common in damage control orthopaedics. There is a lack of comprehensive data evaluating outcomes between these methods. This study compares outcomes of patients stabilized with either TPF or ex-fix, and with early definitive MN only, assessing complications including nonunion and deep infection. Methods: A retrospective review was performed on adult patients with tibia fractures treated with MN followed until fracture union (≥3 months) at a single level-1 trauma center from 2014 to 2022. Medical records were evaluated for nonunion and deep infection. Demographics, injury characteristics, and fixation methods were recorded. Significance between patients who underwent TPF and ex-fix was compared with a matched cohort of early MN using Pearson's exact tests, independent t-tests, and one-way ANOVA, depending on the appropriate variable. Results: 81 patients were included; 27 were temporized with TPF (n = 12) or ex-fix (n = 15). 54 early MN cases defined the matched cohort. All groups had similar patient and fracture characteristics. The difference in rates of nonunion between groups was significant, with TPF, ex-fix, and early MN groups at 17, 40, and 11% respectively (p = 0.027). Early MN had lower rates of nonunion (11% vs. 40%, p = 0.017) and deep infection (13% vs. 40%, p = 0.028) compared to ex-fix. Conclusion: Temporary ex-fix followed by staged MN was associated with higher rates of nonunion and deep infection. There was no difference in complication rates between TPF and early definitive MN. These data suggest that ex-fix followed by MN of tibia fractures should be avoided in favor of early definitive MN when possible. If temporization is needed, TPF may be a better option than ex-fix. Level of Evidence: IV.

Uncertainty estimation using a 3D probabilistic U-Net for segmentation with small radiotherapy clinical trial datasets.

BACKGROUND AND OBJECTIVES: Bio-medical image segmentation models typically attempt to predict one segmentation that resembles a ground-truth structure as closely as possible. However, as medical images are not perfect representations of anatomy, obtaining this ground truth is not possible. A surrogate commonly used is to have multiple expert observers define the same structure for a dataset. When multiple observers define the same structure on the same image there can be significant differences depending on the structure, image quality/modality and the region being defined. It is often desirable to estimate this type of aleatoric uncertainty in a segmentation model to help understand the region in which the true structure is likely to be positioned. Furthermore, obtaining these datasets is resource intensive so training such models using limited data may be required. With a small dataset size, differing patient anatomy is likely not well represented causing epistemic uncertainty which should also be estimated so it can be determined for which cases the model is effective or not. METHODS: We use a 3D probabilistic U-Net to train a model from which several segmentations can be sampled to estimate the range of uncertainty seen between multiple observers. To ensure that regions where observers disagree most are emphasised in model training, we expand the Generalised Evidence Lower Bound (ELBO) with a Constrained Optimisation (GECO) loss function with an additional contour loss term to give attention to this region. Ensemble and Monte-Carlo dropout (MCDO) uncertainty quantification methods are used during inference to estimate model confidence on an unseen case. We apply our methodology to two radiotherapy clinical trial datasets, a gastric cancer trial (TOPGEAR, TROG 08.08) and a post-prostatectomy prostate cancer trial (RAVES, TROG 08.03). Each dataset contains only 10 cases each for model development to segment the clinical target volume (CTV) which was defined by multiple observers on each case. An additional 50 cases are available as a hold-out dataset for each trial which had only one observer define the CTV structure on each case. Up to 50 samples were generated using the probabilistic model for each case in the hold-out dataset. To assess performance, each manually defined structure was matched to the closest matching sampled segmentation based on commonly used metrics. RESULTS: The TOPGEAR CTV model achieved a Dice Similarity Coefficient (DSC) and Surface DSC (sDSC) of 0.7 and 0.43 respectively with the RAVES model achieving 0.75 and 0.71 respectively. Segmentation quality across cases in the hold-out datasets was variable however both the ensemble and MCDO uncertainty estimation approaches were able to accurately estimate model confidence with a p-value < 0.001 for both TOPGEAR and RAVES when comparing the DSC using the Pearson correlation coefficient. CONCLUSIONS: We demonstrated that training auto-segmentation models which can estimate aleatoric and epistemic uncertainty using limited datasets is possible. Having the model estimate prediction confidence is important to understand for which unseen cases a model is likely to be useful.

Population Attributable Fraction of Total Stroke Associated with Modifiable Risk Factors in the United States.

Stroke is a leading cause of death in the United States across all race/ethnicity and sex groups, though disparities exist. We investigated the potential for primary prevention of total first stroke for Americans aged 20 and older, stratified by sex and race/ethnicity. Specifically, we calculated population attributable fractions (PAF) of first stroke for 7 potentially modifiable risk factors: smoking, physical inactivity, poor diet, obesity, hypertension, diabetes, and atrial fibrillation. PAFs are a function of (1) the relative risk of first stroke for people with the exposure and (2) the prevalence of the risk factor in the population. Relative risks came from recent meta-analyses and sex-race/ethnicity-specific prevalence estimates came from the 2015-2018 NHANES or Multi-Ethnic Study of Atherosclerosis (for atrial fibrillation only). Approximately 1/3 (35.7% [CI: 21.6%-49.0%]) for women, 32.7% [CI: 19.2%-45.1%] for men) of strokes were attributable to the 7 risk factors we considered. A 20% proportional reduction in stroke risk factors would result in approximately 37,000 fewer strokes annually in the United States. The estimated PAF was highest for non-Hispanic Black women (39.3% [CI: 24.8%-52.3%]) and lowest for non-Hispanic Asian men (25.5% [CI: 14.6%-36.2%]). For most groups, obesity and hypertension were the largest contributors to stroke rates.

Structural Determinants of Vibrio cholerae FeoB Nucleotide Promiscuity.

Ferrous iron (Fe2+) is required for the growth and virulence of many pathogenic bacteria, including Vibrio cholerae (Vc), the causative agent of the disease cholera. For this bacterium, Feo is the primary system that transports Fe2+ into the cytosol. FeoB, the main component of this system, is regulated by a soluble cytosolic domain termed NFeoB. Recent reanalysis has shown that NFeoBs can be classified as either GTP-specific or NTP-promiscuous, but the structural and mechanistic bases for these differences were not known. To explore this intriguing property of FeoB, we solved the X-ray crystal structures of VcNFeoB in both the apo and GDP-bound forms. Surprisingly, this promiscuous NTPase displayed a canonical NFeoB G-protein fold like GTP-specific NFeoBs. Using structural bioinformatics, we hypothesized that residues surrounding the nucleobase could be important for both nucleotide affinity and specificity. We then solved the X-ray crystal structures of N150T VcNFeoB in the apo and GDP-bound forms to reveal H-bonding differences surround the guanine nucleobase. Interestingly, isothermal titration calorimetry revealed similar binding thermodynamics of the WT and N150T proteins to guanine nucleotides, while the behavior in the presence of adenine nucleotides was dramatically different. AlphaFold models of VcNFeoB in the presence of ADP and ATP showed important conformational changes that contribute to nucleotide specificity among FeoBs. Combined, these results provide a structural framework for understanding FeoB nucleotide promiscuity, which could be an adaptive measure utilized by pathogens to ensure adequate levels of intracellular iron across multiple metabolic landscapes.

Mycobacterium immunogenum acquisition from hospital tap water: a genomic and epidemiologic analysis.

We identified 23 cases of Mycobacterium immunogenum respiratory acquisition linked to a colonized plumbing system at a new hospital addition. We conducted a genomic and epidemiologic investigation to assess for clonal acquisition of M. immunogenum from hospital water sources and improve understanding of genetic distances between M. immunogenum isolates. We performed whole-genome sequencing on 28 M. immunogenum isolates obtained from August 2013 to July 2021 from patients and water sources on four intensive care and intermediate units at an academic hospital. Study hospital isolates were recovered from 23 patients who experienced de novo respiratory isolation of M. immunogenum and from biofilms obtained from five tap water outlets. We also analyzed 10 M. immunogenum genomes from previously sequenced clinical (n = 7) and environmental (n = 3) external control isolates. The 38-isolate cohort clustered into three clades with pairwise single-nucleotide polymorphism (SNP) distances ranging from 0 to 106,697 SNPs. We identified two clusters of study hospital isolates in Clade 1 and one cluster in Clade 2 for which clinical and environmental isolates differed by fewer than 10 SNPs and had less than 0.5% accessory genome variation. A less restrictive combined threshold of 40 SNPs and 5% accessory genes reliably captured additional isolates that met clinical criteria for hospital acquisition, but 12 (4%) of 310 epidemiologically unrelated isolate pairs also met this threshold. Core and accessory genome analyses confirmed respiratory acquisition of multiple clones of M. immunogenum from hospital water sources to patients. When combined with epidemiologic investigation, genomic thresholds accurately distinguished hospital acquisition.

Rates of interlock screw back-out are high with the retrograde femoral nailing advanced system for distal femur fractures.

PURPOSE: The retrograde femoral nailing advanced (RFNA) system (DePuy synthes) is a commonly used implant for the fixation of low distal femur and periprosthetic fractures. There is concern that the rate of distal interlock screw back-out may be higher for the RFNA compared to other nails (ON). The purpose of this study was to evaluate the incidence of interlock screw back-out and associated screw removal for RFNA versus ON, along with associated risk factors. METHODS: A retrospective comparative study of patients who underwent retrograde nailing for a distal femur fracture at an academic level one trauma center was performed. The incidence of distal interlock screw back-out and need for screw removal were compared for RFNA versus a propensity score matched cohort who received other nails. RESULTS: One hundred and ten patients underwent retrograde nailing with the RFNA for a distal femur fracture from 2015 to 2022 (average age: 66, BMI: 32, 52.7% smokers, 54.5% female, 61.8%). There was a significantly higher rate of interlock back-out in the RFNA group compared to the ON (27 patients, 24.5% vs 12 patients, 10.9%, p = 0.01), which occurred 6.3 weeks postoperatively. Screw removal rates for back-out were not significantly different for the RFNA group versus ON (8 patients, 7.3% vs 3 patients, 2.7%, p = 0.12). CONCLUSION: In this retrospective comparative study of distal femur fractures treated with retrograde nailing, the RFNA implant was associated with an increased risk of distal interlock screw back-out compared to other nails.

Orally Inhaled Flecainide for Conversion of Atrial Fibrillation to Sinus Rhythm: INSTANT Phase 2 Trial.

BACKGROUND: INSTANT (INhalation of flecainide to convert recent-onset SympTomatic Atrial fibrillatioN to sinus rhyThm) was a multicenter, open-label, single-arm study of flecainide acetate oral inhalation solution (FlecIH) for acute conversion of recent-onset (≤48 hours) symptomatic atrial fibrillation (AF) to sinus rhythm. OBJECTIVES: This study investigated the efficacy and safety in 98 patients receiving a single dose of FlecIH delivered via oral inhalation. METHODS: Patients self-administered FlecIH over 8 minutes in a supervised medical setting using a breath-actuated nebulizer and were continuously monitored for 90 minutes using a 12-lead Holter. RESULTS: Mean age was 60.5 years, mean body mass index was 27.0 kg/m2, and 34.7% of the patients were women. All patients had ≥1 AF-related symptoms at baseline, and 87.8% had AF symptoms for ≤24 hours. The conversion rate was 42.6% (95% CI: 33.0%-52.6%) with a median time to conversion of 14.6 minutes. The conversion rate was 46.9% (95% CI: 36.4%-57.7%) in a subpopulation that excluded predose flecainide exposure for the current AF episode. Median time to discharge among patients who converted was 2.5 hours, and only 2 patients had experienced AF recurrence by day 5. In the conversion-no group, 44 (81.5%) patients underwent electrical cardioversion by day 5. The most common adverse events were related to oral inhalation of flecainide (eg, cough, oropharyngeal irritation/pain), which were mostly of mild intensity and limited duration. CONCLUSIONS: The risk-benefit of orally inhaled FlecIH for acute cardioversion of recent-onset AF appears favorable. FlecIH could provide a safe, effective, and convenient first-line therapeutic option. (INhalation of Flecainide to Convert Recent Onset SympTomatic Atrial Fibrillation to siNus rhyThm [INSTANT]; NCT03539302).

The CD4 transmembrane GGXXG and juxtamembrane (C/F)CV+C motifs mediate pMHCII-specific signaling independently of CD4-LCK interactions.

CD4+ T cell activation is driven by five-module receptor complexes. The T cell receptor (TCR) is the receptor module that binds composite surfaces of peptide antigens embedded within MHCII molecules (pMHCII). It associates with three signaling modules (CD3γε, CD3δε, and CD3ζζ) to form TCR-CD3 complexes. CD4 is the coreceptor module. It reciprocally associates with TCR-CD3-pMHCII assemblies on the outside of a CD4+ T cells and with the Src kinase, LCK, on the inside. Previously, we reported that the CD4 transmembrane GGXXG and cytoplasmic juxtamembrane (C/F)CV+C motifs found in eutherian (placental mammal) CD4 have constituent residues that evolved under purifying selection (Lee et al., 2022). Expressing mutants of these motifs together in T cell hybridomas increased CD4-LCK association but reduced CD3ζ, ZAP70, and PLCγ1 phosphorylation levels, as well as IL-2 production, in response to agonist pMHCII. Because these mutants preferentially localized CD4-LCK pairs to non-raft membrane fractions, one explanation for our results was that they impaired proximal signaling by sequestering LCK away from TCR-CD3. An alternative hypothesis is that the mutations directly impacted signaling because the motifs normally play an LCK-independent role in signaling. The goal of this study was to discriminate between these possibilities. Using T cell hybridomas, our results indicate that: intracellular CD4-LCK interactions are not necessary for pMHCII-specific signal initiation; the GGXXG and (C/F)CV+C motifs are key determinants of CD4-mediated pMHCII-specific signal amplification; the GGXXG and (C/F)CV+C motifs exert their functions independently of direct CD4-LCK association. These data provide a mechanistic explanation for why residues within these motifs are under purifying selection in jawed vertebrates. The results are also important to consider for biomimetic engineering of synthetic receptors.

A survey of medical school aspirant perceptions of an unexpected lottery-facilitated admissions adaptation.

INTRODUCTION: Due to the COVID-19 pandemic, the Undergraduate Medical Doctor (MD) Programme at McMaster University (Hamilton, Canada) was unable to run in-person medical school interviews in March 2020, prompting an alternate solution that maximised admission opportunities for Indigenous applicants, prioritised admission for those rated most highly in the interview determination process, and allocated subsequent offers via lottery. METHODS: A short survey was administered to applicants who had been offered an admissions interview and were subsequently impacted by the admissions adaptations. The survey elicited perceptions of the adaptation through Likert scale ratings and free-text responses. Survey data were analysed via a sequential (quantitative to qualitative) mixed-methods design. RESULTS: 196 of 552 potential participants completed the survey. Across quantitative and qualitative analyses, respondents reported that the adaptation had a negative impact on their professional development and personal life. Ratings of negative perception were greater for those who did not receive an offer than for those who accepted or declined an offer. Free text responses emphasised considerable criticism for the lottery portion of the adaptation and displeasure that efforts made in constructing applications were less relevant than anticipated. DISCUSSION: The negative responses to this unexpected change highlight the profound upstream impact admission policies have on the preapplication behaviours of aspiring medical students. The outcomes support a refined understanding of the value candidates place on the interview in appraising their own suitability for a career as a physician.

The influence of viewing time on visual diagnostic accuracy: Less is more.

BACKGROUND: Understanding the factors that contribute to diagnostic errors is critical if we are to correct or prevent them. Some scholars influenced by the default interventionist dual-process theory of cognition (dual-process theory) emphasise a narrow focus on individual clinician's faulty reasoning as a significant contributor. In this paper, we examine the validity of claims that dual process theory is a key to error reduction. METHODS: We examined the relationship between a clinical experience (staff and resident physicians) and viewing time on accuracy for categorising chest X-rays (CXRs) and electrocardiograms (ECGs). In two studies, participants categorised images as normal or abnormal, presented at viewing times of 175, 250, 500 and 1000 ms, to encourage System 1 processing. Study 2 extended viewing times to 1, 5, 10 and 20 s to allow time for System 2 processing and a diagnosis. Descriptives and repeated measures analysis of variance were used to analyse the proportion of true and false positive rates (TP and FP) as well as correct diagnoses. RESULTS: In Study 1, physicians were able to detect abnormal CXRs (0.78) and ECGs (0.67) with relatively high accuracy. The effect of experience was found for ECGs only, as staff physicians (0.71, 95% CI = 0.66-0.75) had higher ECG TP than resident physicians (0.63, 95% CI = 0.58-0.68) in Study 1, and staff had lower ECG FP (0.10, 95% CI = 0.03-0.18) than resident physicians (0.27, 95% CI = 0.20-0.33) in Study 2. In other comparisons, experience was equivocal for ECG FPs and CXR TPs and FPs. In Study 2, overall diagnostic accuracy was similar for both ECGs and CXRs, (0.74). There were small interactions between experience and time for TP in ECGs and FP in CXRs, which are discussed further in the discussion and offer insights into the relationship between processing and experience. CONCLUSION: Overall, our findings raise concerns about the practical application of models that link processing type to diagnostic error, or to specific diagnostic error reduction strategies.

Trifocal femur fracture with intracapsular femoral neck, open diaphyseal, and distal complete articular fractures.

We describe a trifocal femur injury with intracapsular femoral neck fracture, diaphyseal fracture with bone loss, and distal complete articular (AO/OTA C type) fracture, an injury rarely described in the literature. Surgical management utilized a not-yet-reported implant combination: screw-side plate device for the intracapsular femoral neck, retrograde nail for the diaphysis, and lag screws plus mini fragment buttress plating for the distal fracture. The patient had uneventful fracture union with no changes in alignment. Given the rarity and complexity of this injury, there is little consensus on surgical technique and implant choice. This case demonstrates a modernized approach that may be useful for surgeons who encounter similar fracture patterns in their practice.

ReThinking clinical reasoning: A paradigm shift.

Numerous studies have demonstrated that our healthcare systems and medical education programs are fundamentally flawed. In North America and Europe, most systems were built upon values and structures that have historically benefitted middle and upper class males of European descent in the global north. As a result, there continue to be systemic biases that are pervasive throughout our healthcare systems and medical education programs. This has led to inequities in health outcomes and clinical reasoning practices which marginalize several communities. These biases are perpetuated as we continue to lead medical education research and practice with traditional values and views of evidence. To address these issues, we proposed a 'flipped' conference in which three interdisciplinary writing teams, comprised of both junior and senior academics, clinicians, and researchers, were invited to rethink the foundations of clinical reasoning. In the months leading up to the conference, each writing team explored a specific topic related to clinical reasoning and racial equity. The papers, presented during the virtual conference are now available in this issue of the Journal for the Evaluation of Clinical Practice. In addition, 6 more publications were added to this special topic to showcase new evidence and theory that builds on the recommendations in the three core papers.

Carnosine/histidine-containing dipeptide supplementation improves depression and quality of life: systematic review and meta-analysis of randomized controlled trials.

CONTEXT: Mental ill-health is a common and growing issue, affecting 1 in 8 individuals or 970 million people worldwide in 2019. Histidine-containing dipeptides (HCDs) have been suggested to mitigate some aspects of mental ill-health, but a quantitative synthesis of the evidence is lacking. Therefore, a systematic review and meta-analysis of randomized controlled trials was conducted. OBJECTIVE: To summarize the evidence on the effects of HCDs on mental health outcomes. DATA SOURCE: A systematic literature search was performed using electronic databases (Medline via Ovid, Embase via Ovid, Scopus, Google Scholar, and Cochrane) from inception to October, 2022. DATA EXTRACTION: Two authors independently extracted data using a structured extraction format. DATA ANALYSIS: Data analysis was performed using STATA version 17. Random-effects models were used, and heterogeneity was assessed using the I2 test. Quality appraisal was performed using the Cochrane risk-of-bias 2.0 tool and the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) approach. CONCLUSION: 5507 studies were identified, with 20 studies fulfilling the inclusion criteria. Eighteen studies comprising 776 participants were included in the meta-analysis. HCD supplementation (anserine/carnosine, l-carnosine, ß-alanine) caused a significant reduction in depression scores measured with the Becks Depression Inventory (-0.79; 95% CI: -1.24, -0.35; moderate certainty on GRADE) when compared with placebo. An increase in quality-of-life scores measured with the 36-item Short-Form survey (SF-36) (0.65; 95% CI: 0.00, 1.30) and low certainty on GRADE in HCDs (anserine/carnosine, l-carnosine, ß-alanine) when compared with placebo were found. However, the rest of the outcomes did not show a significant change between HCD supplementation and placebo. Although the number of studies included in the meta-analysis was modest, a significant mean reduction was observed in depression score as well as an increase in quality-of-life score for the HCD group when compared with placebo. Most of the studies included had small sample sizes with short follow-up periods and moderate to high risk of bias, highlighting the need for further, well-designed studies to improve the evidence base. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42017075354.

Crowdsourcing a diagnosis? Exploring the accuracy of the size and type of group diagnosis: an experimental study.

BACKGROUND: The consultation process, where a clinician seeks an opinion from another clinician, is foundational in medicine. However, the effectiveness of group diagnosis has not been studied. OBJECTIVE: To compare individual diagnosis to group diagnosis on two dimensions: group size (n=3 or 6) and group process (interactive or artificial groups). METHODOLOGY: Thirty-six internal or emergency medicine residents participated in the study. Initially, each resident worked through four written cases on their own, providing a primary diagnosis and a differential diagnosis. Next, participants formed into groups of three. Using a videoconferencing platform, they worked through four additional cases, collectively providing a single primary diagnosis and differential diagnosis. The process was repeated using a group of six with four new cases. Cases were all counterbalanced. Retrospectively, nominal (ie, artificial) groups were formed by aggregating individual participant data into subgroups of three and six and analytically computing scores. Presence of the correct diagnosis as primary diagnosis or included in the differential diagnosis, as well as the number of diagnoses mentioned, was calculated for all conditions. Means were compared using analysis of variance. RESULTS: For both authentic and nominal groups, the diagnostic accuracy of group diagnosis was superior to individual for both the primary diagnosis and differential diagnosis. However, there was no improvement in diagnostic accuracy when comparing a group of three to a group of six. Interactive and nominal groups were equivalent; however, this may be an artefact of the method used to combine data. CONCLUSIONS: Group diagnosis improves diagnostic accuracy. However, a larger group is not necessarily superior to a smaller group. In this study, interactive group discussion does not result in improved diagnostic accuracy.

Pulsed Field Ablation Index-Guided Ablation for Lesion Formation: Impact of Contact Force and Number of Applications in the Ventricular Model.

BACKGROUND: The effect of contact force (CF) on lesion formation is not clear during pulsed field ablation (PFA). The aim of this study was to evaluate the impact of CF, PFA, and their interplay through the PFA index (PF index) formula on the ventricular lesion size in swine. METHODS: PFA was delivered through the CF-sensing OMNYPULSE catheter. Predefined PFA applications (×3, ×6, ×9, and ×12) were delivered maintaining low (5-25 g), high (26-50 g), and very high (51-80 g) CFs. First, PFA lesions were evaluated on necropsy in 11 swine to investigate the impact of CF/PFA-and their integration in the PF index equation-on lesion size (study characterization). Then, 3 different PF index thresholds-300, 450, and 600-were tested in 6 swine to appraise the PF index accuracy to predict the ventricular lesion depth (study validation). RESULTS: In the study characterization data set, 111 PFA lesions were analyzed. CF was 32±17 g. The average lesion depth and width were 3.5±1.2 and 12.0±3.5 mm, respectively. More than CF and PFA dose alone, it was their combined effect to impact lesion depth through an asymptotically increasing relationship. Likewise, not only was the PF index related to lesion depth in the study validation data set (r2=0.66; P<0.001) but it also provided a prediction accuracy of the observed depth of ±2 mm in 69/73 lesions (95%). CONCLUSIONS: CF and PFA applications play a key role in lesion formation during PFA. Further studies are required to evaluate the best PFA ablation settings to achieve transmural lesions.

Pharmacokinetics, Safety, and Tolerability of a Single 5-Day Treatment of Tirbanibulin Ointment 1% in 100 cm2 : A Phase 1 Maximal-Use Trial in Patients with Actinic Keratosis.

Tirbanibulin ointment 1% is approved in the United States and Europe for the treatment of actinic keratosis with demonstrated efficacy, safety, and tolerability when applied over a field up to 25 cm2 . This Phase 1 maximal-use trial determines the plasma pharmacokinetics, safety, and tolerability of tirbanibulin ointment 1% applied to 100 cm2 of the face or balding scalp in adults with actinic keratosis. Twenty-eight patients self-applied tirbanibulin once daily for a single 5-day treatment course. On Day 5, the mean maximum plasma concentration was 1.06 ng/mL and area under the plasma concentration-time curve during a dosing interval was 16.2 ng â€¢ h/mL. Systemic exposure was approximately 4-fold higher than in a previous pharmacokinetic study with a 25 cm2 field, consistent with the increase in the treated area. Tirbanibulin applied to a 100-cm2 treatment field showed favorable safety and tolerability. The most common treatment-emergent adverse events were application site reactions (in 35.7% of patients). All treatment-emergent adverse events and most of the tolerability signs were mild/moderate and resolved or returned to baseline by Day 29. In summary, under maximal-use conditions, tirbanibulin ointment 1% was safe and well tolerated supporting its potential use over a field up to 100 cm2 .

p21 as a Predictor and Prognostic Indicator of Clinical Outcome in Rectal Cancer Patients.

The cell cycle plays a key and complex role in the development of human cancers. p21 is a potent cyclin-dependent kinase inhibitor (CDKI) involved in the promotion of cell cycle arrest and the regulation of cellular senescence. Altered p21 expression in rectal cancer cells may affect tumor cells' behavior and resistance to neoadjuvant and adjuvant therapy. Our study aimed to ascertain the relationship between the differential expression of p21 in rectal cancer and patient survival outcomes. Using tissue microarrays, 266 rectal cancer specimens were immunohistochemically stained for p21. The expression patterns were scored separately in cancer cells retrieved from the center and the periphery of the tumor; compared with clinicopathological data, tumor regression grade (TRG), disease-free, and overall survival. Negative p21 expression in tumor periphery cells was significantly associated with longer overall survival upon the univariate (p = 0.001) and multivariable analysis (p = 0.003, HR = 2.068). Negative p21 expression in tumor periphery cells was also associated with longer disease-free survival in the multivariable analysis (p = 0.040, HR = 1.769). Longer overall survival times also correlated with lower tumor grades (p= 0.011), the absence of vascular and perineural invasion (p = 0.001; p < 0.005), the absence of metastases (p < 0.005), and adjuvant treatment (p = 0.009). p21 expression is a potential predictive and prognostic biomarker for clinical outcomes in rectal cancer patients. Negative p21 expression in tumor periphery cells demonstrated significant association with longer overall survival and disease-free survival. Larger prospective studies are warranted to investigate the ability of p21 to identify rectal cancer patients who will benefit from neoadjuvant and adjuvant therapy.

Genetic alterations in thyroid cancer mediating both resistance to BRAF inhibition and anaplastic transformation.

A subset of thyroid cancers present at advanced stage or with dedifferentiated histology and have limited response to standard therapy. Tumors harboring the BRAF V600E mutation may be treated with BRAF inhibitors; however, tumor response is often short lived due to multiple compensatory resistance mechanisms. One mode of resistance is the transition to an alternative cell state, which on rare occasions can correspond to tumor dedifferentiation. DNA sequencing and RNA expression profiling show that thyroid tumors that dedifferentiate after BRAF inhibition are enriched in known genetic alterations that mediate resistance to BRAF blockade, and may also drive tumor dedifferentiation, including mutations in the PI3K/AKT/MTOR (PIK3CA, MTOR), MAP/ERK (MET, NF2, NRAS, RASA1), SWI/SNF chromatin remodeling complex (ARID2, PBRM1), and JAK/STAT pathways (JAK1). Given these findings, recent investigations have evaluated the efficacy of dual-target therapies; however, continued lack of long-term tumor control illustrates the complex and multifactorial nature of these compensatory mechanisms. Transition to an immune-suppressed state is another correlate of BRAF inhibitor resistance and tumor dedifferentiation, suggesting a possible role for concurrent targeted therapy with immunotherapy. Investigations into combined targeted and immunotherapy are ongoing, but early results with checkpoint inhibitors, viral therapies, and CAR T-cells suggest enhanced anti-tumor immune activity with these combinations.