GET: a foundation model of transcription across human cell types.

Transcriptional regulation, involving the complex interplay between regulatory sequences and proteins, directs all biological processes. Computational models of transcription lack generalizability to accurately extrapolate in unseen cell types and conditions. Here, we introduce GET, an interpretable foundation model designed to uncover regulatory grammars across 213 human fetal and adult cell types. Relying exclusively on chromatin accessibility data and sequence information, GET achieves experimental-level accuracy in predicting gene expression even in previously unseen cell types. GET showcases remarkable adaptability across new sequencing platforms and assays, enabling regulatory inference across a broad range of cell types and conditions, and uncovering universal and cell type specific transcription factor interaction networks. We evaluated its performance on prediction of regulatory activity, inference of regulatory elements and regulators, and identification of physical interactions between transcription factors. Specifically, we show GET outperforms current models in predicting lentivirus-based massive parallel reporter assay readout with reduced input data. In fetal erythroblasts, we identify distal (>1Mbp) regulatory regions that were missed by previous models. In B cells, we identified a lymphocyte-specific transcription factor-transcription factor interaction that explains the functional significance of a leukemia-risk predisposing germline mutation. In sum, we provide a generalizable and accurate model for transcription together with catalogs of gene regulation and transcription factor interactions, all with cell type specificity.

Enhancing stroke risk and prognostic timeframe assessment with deep learning and a broad range of retinal biomarkers.

Stroke stands as a major global health issue, causing high death and disability rates and significant social and economic burdens. The effectiveness of existing stroke risk assessment methods is questionable due to their use of inconsistent and varying biomarkers, which may lead to unpredictable risk evaluations. This study introduces an automatic deep learning-based system for predicting stroke risk (both ischemic and hemorrhagic) and estimating the time frame of its occurrence, utilizing a comprehensive set of known retinal biomarkers from fundus images. Our system, tested on the UK Biobank and DRSSW datasets, achieved AUROC scores of 0.83 (95% CI: 0.79-0.85) and 0.93 (95% CI: 0.9-0.95), respectively. These results not only highlight our system's advantage over established benchmarks but also underscore the predictive power of retinal biomarkers in assessing stroke risk and the unique effectiveness of each biomarker. Additionally, the correlation between retinal biomarkers and cardiovascular diseases broadens the potential application of our system, making it a versatile tool for predicting a wide range of cardiovascular conditions.

Responses to Basal Insulin Glargine (300 U/mL and 100 U/mL) with or Without Pre-prandial Insulin in Pre-treated Subphenotypes of Type 2 Diabetes: Insights from a Post Hoc Analysis.

INTRODUCTION: This study aimed to evaluate glycemic outcomes in subphenotypes of type 2 diabetes (T2D) with HbA1c > 7.0%, previously on basal insulin (pre-BI) alone (≥ 42 U/day) or on basal-bolus therapy (pre-BB), and who were switched to either basal insulin glargine 300 U/mL (IGlar-300) or 100 U/mL (IGlar-100), with or without pre-prandial insulin. METHODS: Participants from EDITION 2 (pre-BI, n = 785), and EDITION 1 (pre-BB, n = 792) trials were assigned retrospectively to subphenotypes of T2D: severe insulin deficient diabetes (SIDD), mild age-related diabetes (MARD), mild obesity diabetes (MOD), and severe insulin resistant diabetes (SIRD). Key efficacy and safety parameters were analyzed at baseline, and after 26 weeks, for IGlar-300 and IGlar-100 pooled groups according to subphenotypes. Outcomes were also compared with insulin-naïve subphenotypes on oral antihyperglycemic drugs (OADs) from the EDITION 3 trial (pre-OAD, n = 858). RESULTS: Pre-BI and pre-BB treated subphenotypes with SIDD had a higher mean HbA1c (8.9% and 9.1%) at baseline compared to those of MARD (7.7% and 7.8%) and MOD (8.1% and 8.2%) and after 26 weeks remained above target HbA1c (7.7% and 8.0%) despite mean glargine doses of 0.7 to 1.0 U/kg/day and pre-prandial insulin use in the pre-BB SIDD subgroup. Pre-BB treated individuals with MARD and MOD achieved lower HbA1c levels (6.9% and 7.2%) than the pre-BI groups (7.3% and 7.5%) despite similar mean FPG levels (123-130 mg/dL). Only 19-22% of participants with SIDD achieved HbA1c < 7.0% compared to 33-51% with MARD and MOD, respectively. Pre-BI and pre-BB treated subphenotypes experienced more hypoglycemia than pre-OAD treated subphenotypes. CONCLUSION: Individuals with T2D assigned post hoc to the SIDD subphenotype achieved suboptimal glycemic control with glargine regimens including basal-bolus therapy, alerting clinicians to improve further diabetes treatment, particularly post-prandial glycemic control, in individuals with SIDD.

Temporally dense monitoring of pathogen occurrence at four drinking-water well sites - Insights and Implications.

Yearlong, event based, microbiological and chemical sampling was conducted at four public water supply well sites spanning a range of geologic settings and well depths to look for correlation between precipitation events and microbial occurrence. Near-continuous monitoring using autosamplers occurred just before, during, and after 5-7 sampling events triggered by rainfall and/or snowmelt. Microbial genetic material was noted at all four locations during all but one sampling event, but was exceedingly variable in time, where one sample would have no detections and the next sample could be a relatively high concentration. The highest microbial sums (microbial concentrations summed over an event) were observed during months in which precipitation exceeded historical averages. Extended wet conditions through the spring thaw resulted in the highest percentage of microbial positive samples, though at relatively low concentrations. Sampling events that followed drier than normal periods showed longer lag times between the onset of precipitation and microbial occurrence, as well as lower microbial detection rates. Although a general lag time pattern was observed at each site, the largest offset in time was observed at the site with the greatest depth to water. The study's temporally dense representation of drinking water pathogen characterization suggests that single event or infrequent periodic sampling of a drinking water supply cannot provide a representative characterization of the probability that pathogens are present, which likely has ramifications for calculating health risk assessments.

Learning needs of junior doctors in otolaryngology: a qualitative study.

OBJECTIVES: There is concern that junior doctors are not prepared for their post-graduate attachments in ENT. The aims of this study were to capture the learning priorities of those in the ENT first on-call role and facilitate further educational opportunities to address these needs. METHOD: Semi-structured interviews were undertaken to explore the learning needs of junior doctors with seven junior and two senior ENT clinicians. RESULTS: The thematic analysis generated three themes: the role of the ENT Junior; the perceived, expressed and prescribed learning needs; and attitudes towards future learning. These themes explored the misalignment between undergraduate training and post-graduate expectations, the lack of competence in ENT practical skills and the need for focused ENT training prior to commencing on-call shifts. CONCLUSION: All interviewees identified the need for greater experience in practical interventional skills prior to their ENT attachments and expressed interest towards a standardised, bootcamp-style induction with simulated emergency experience.

Feasibility of an enhanced low-fidelity ear simulator for otomicroscopy training.

OBJECTIVE: Otoscopic skills are essential for ENT doctors. Early-stage doctors develop skills whilst treating patients, with minimal teaching, potentially increasing risk to patients. Simulation allows skill development without patient risk; however, simulation often requires subjective expert review of technique. This study compared enhanced low-fidelity simulation with performance feedback against standard simulation using a basic otoscopy skills simulator. METHODS: Two low-fidelity ear simulators were created: a basic model without feedback and an enhanced model which alarms when the aural instrument tip touches the canal wall. Participants were evaluated in a randomised crossover pilot study, using both models to assess whether objective feedback reduced tip touches. RESULTS: The enhanced simulator reduced tip touches more than the control model, suggesting better and more sustained skill uptake. Participants reported that the enhanced model improved learning. CONCLUSION: Enhanced low-fidelity models provide a low-cost opportunity to improve otoscopy skills without patient risk or the need for subjective expert feedback.

Stratifying risk of malignancy in cystic lateral neck lumps: a multivariant analysis of demographic, radiological and histological investigation factors and the development of a patient-centred risk-predictive tool for malignancy.

BACKGROUND: Management of lateral cystic neck masses with no apparent upper aerodigestive tract primary tumour in adults is controversial. Imaging modalities and fine needle aspiration cytology often struggle to distinguish the presence of malignancy. METHOD: This study entailed a multicentre retrospective review of all patients with isolated lateral cystic neck masses from 2012 to 2018 in three Welsh health boards, utilising demographic data and first-line investigations (ultrasound scanning and fine needle aspiration cytology) to develop an evidence-based predictive tool for risk of malignancy. RESULTS: It was found that 29.1 per cent of cystic lesions were malignant on final histology. Age, male gender, non-benign ultrasound scan findings and fine needle aspiration cytology were significant risk factors on univariate analysis. The final multivariate analysis predicted a risk of malignancy ranging from 2.1 to 65.0 per cent depending on the covariate pattern. Smoking status was non-significant. CONCLUSION: A rigorous, risk-stratified approach to the management of these patients should aid the clinician in minimising morbidity and optimising resources.

Treatment responses to basal insulin glargine 300 U/ml and glargine 100 U/ml in newly defined subphenotypes of type 2 diabetes: A post hoc analysis of the EDITION 3 randomized clinical trial.

INTRODUCTION: To compare responses to basal insulin glargine 300 U/ml (IGlar-300) and 100 U/ml (IGlar-100) in newly defined subphenotypes of type 2 diabetes. METHODS: Insulin-naive participants (n = 858) from the EDITION 3 trial were assigned to subphenotypes 'Mild Age-Related Diabetes (MARD)', 'Mild Obesity Diabetes (MOD)', 'Severe Insulin Resistant Diabetes (SIRD)' and 'Severe Insulin Deficient Diabetes (SIDD)'. Key variables were analysed at baseline and 26 weeks. RESULTS: Participants were comprised of MOD 56.1% (n = 481), SIDD 22.1% (n = 190), MARD 18.2% (n = 156) and SIRD 3.0% (n = 26). After 26 weeks a similar decrease in glycated haemoglobin (HbA1c) and fasting plasma glucose (FPG) of 16-19 mmol/mol and 1.4-1.7 mmol/L, respectively, occurred in MARD and MOD with both insulins. SIDD had the most elevated HbA1c and FPG (80-83 mmol/mol/11.1-11.4 mmol/L) and reduction in both HbA1c and FPG was greater with IGlar-100 than with IGlar-300 (-18 vs. -15 mmol/mol and -1.6 vs. -1.3 mmol/L, respectively; each p = .03). In SIDD, despite receiving the highest basal insulin doses, HbA1c decline (57-60 mmol/mol/7.3-7.6%) was suboptimal at week 26. In MOD and SIDD lower incidences with IGlar-300 were found for level 1 nocturnal hypoglycaemia [odds ratio (OR) 0.59, 95% confidence intervals (CI) 0.36-0.97; OR 0.49, 95% CI 0.24-0.99]. In addition, fewer level 2 hypoglycaemia episodes occurred at any time with IGlar-300 in SIDD (OR 0.31, 95% CI 0.13-0.77). CONCLUSION: Both insulins produce comparable outcomes in type 2 diabetes subphenotypes, but in SIDD, add-on treatment to basal insulin is required to achieve glycaemic targets.

Undergraduate perceptions on the educational value of a novel ENT e-Learning platform.

ENT is a consistently under-represented specialty in medical school curricula. With social distancing measures limiting face-to-face (FtF) teaching and clinical opportunities, we created an e-Learning platform to consolidate and improve knowledge on common ENT emergencies. Following invitation to medical students undergoing their rotation in ENT at University Hospital Wales (UHW) Cardiff, five focus groups were shown an e-Learning module and interviewed between June and July 2021. 13 medical students participated in total (9 female, 4 male, median age 22 years). These structured interviews were recorded and transcribed. Transcripts were analysed using the qualitative data analysis software NVivo (QSR International, UK). The modules were found to be concise, clinically relevant and beneficial to student confidence in recognising and managing ENT emergencies. While e-Learning will likely never replace face-to-face learning, it was perceived to be a beneficial resource both academically and practically- especially in the context of limited clinical opportunities.

Key indices of glycaemic variability for application in diabetes clinical practice.

Near normal glycaemic control in diabetes consists to target daily glucose fluctuations and quarterly HbA1c oscillations in addition to overall glucose exposure. Consequently, the prerequisite is to define simple, and mathematically undisputable key metrics for the short- and long-term variability in glucose homeostasis. As the standard deviations (SD) of either glucose or HbA1c are dependent on their means, the coefficient of variation (CV = SD/mean) should be applied instead as it that avoids the correlation between the SD and mean values. A CV glucose of 36% is the most appropriate threshold between those with stable versus labile glucose homeostasis. However, when near normal mean glucose concentrations are achieved a lower CV threshold of <27 % is necessary for reducing the risk for hypoglycaemia to a minimal rate. For the long-term variability in glucose homeostasis, a CVHbA1c < 5 % seems to be a relevant recommendation for preventing adverse clinical outcomes.

Climate-mediated population dynamics for the world's most endangered sea turtle species.

Restricted range, and subsequently small population size, render Kemp's ridley sea turtles (Lepidochelys kempii) the most globally endangered sea turtle species. For at least two decades preceding conservation, high egg harvest rates reduced annual cohort recruitment. Despite > 50 years of dedicated conservation, annual nest counts remain well below a landmark 1947 level. Prior studies attribute less robust than anticipated nest count rebound to multiple contemporary concerns; however, analyses herein convey optimistic interpretation. In objective 1, improved analysis of the ratio of hatchlings to nests since 1966 suggested age structure stabilization as a more likely basis for nest count trends after 2005 than density-dependent effects. In objective 2, multiple regression revealed a lagged (≤ 13 years prior) climate influence on nests (adj. r2 = 0.82) and hatchlings per nest (adj. r2 = 0.94) during 2006-2022. In objectives 3 and 4, a simulator modeled population response to changes in a suite of demographic rates including survival. Across 32 models, high survival and dynamic cohort sex ratio, sexual maturity age, and the ratio of clutch frequency to remigration interval best explained nesting trends during 1966-2022. These novel findings provide alternative perspective for evaluating species recovery criteria and in turn refine future nest trend expectations.

[Adaptive repetitive control of wrist tremor suppression based on functional electrical stimulation].

Tremor is an involuntary and repetitive swinging movement of limb, which can be regarded as a periodic disturbance in tremor suppression system based on functional electrical stimulation (FES). Therefore, using repetitive controller to adjust the level and timing of FES applied to the corresponding muscles, so as to generate the muscle torque opposite to the tremor motion, is a feasible means of tremor suppression. At present, most repetitive control systems based on FES assume that tremor is a fixed single frequency signal, but in fact, tremor may be a multi-frequency signal and the tremor frequency also varies with time. In this paper, the tremor data of intention tremor patients are analyzed from the perspective of frequency, and an adaptive repetitive controller with internal model switching is proposed to suppress tremor signals with different frequencies. Simulation and experimental results show that the proposed adaptive repetitive controller based on parallel multiple internal models and series high-order internal model switching can suppress tremor by up to 84.98% on average, which is a significant improvement compared to the traditional single internal model repetitive controller and filter based feedback controller. Therefore, the adaptive repetitive control method based on FES proposed in this paper can effectively address the issue of wrist intention tremor in patients, and can offer valuable technical support for the rehabilitation of patients with subsequent motor dysfunction.

Convergence and transdisciplinary teaching in quantitative biology.

The United States National Science and Technology Council has made a call for improving STEM (Science, Technology, Engineering, and Mathematics) education at the convergence of science, technology, engineering, and mathematics. The National Science Foundation (NSF) views convergence as the merging of ideas, approaches, and technologies from widely diverse fields of knowledge to stimulate innovation and discovery. Teaching convergency requires moving to the transdisciplinary level of integration where there is deep integration of skills, disciplines, and knowledge to solve a challenging real-world problem. Here we present a summary on convergence and transdisciplinary teaching. We then provide examples of convergence and transdisciplinary teaching in plant biology, and conclude by discussing limitations to contemporary conceptions of convergency and transdisciplinary STEM.

Corrigendum: Ischemic and haemorrhagic stroke risk estimation using a machine-learning-based retinal image analysis.

[This corrects the article DOI: 10.3389/fneur.2022.916966.].

Extended Sentinel Monitoring of Helicoverpa zea Resistance to Cry and Vip3Aa Toxins in Bt Sweet Corn: Assessing Changes in Phenotypic and Allele Frequencies of Resistance.

Transgenic corn and cotton that produce Cry and Vip3Aa toxins derived from Bacillus thuringiensis (Bt) are widely planted in the United States to control lepidopteran pests. The sustainability of these Bt crops is threatened because the corn earworm/bollworm, Helicoverpa zea (Boddie), is evolving a resistance to these toxins. Using Bt sweet corn as a sentinel plant to monitor the evolution of resistance, collaborators established 146 trials in twenty-five states and five Canadian provinces during 2020-2022. The study evaluated overall changes in the phenotypic frequency of resistance (the ratio of larval densities in Bt ears relative to densities in non-Bt ears) in H. zea populations and the range of resistance allele frequencies for Cry1Ab and Vip3Aa. The results revealed a widespread resistance to Cry1Ab, Cry2Ab2, and Cry1A.105 Cry toxins, with higher numbers of larvae surviving in Bt ears than in non-Bt ears at many trial locations. Depending on assumptions about the inheritance of resistance, allele frequencies for Cry1Ab ranged from 0.465 (dominant resistance) to 0.995 (recessive resistance). Although Vip3Aa provided high control efficacy against H. zea, the results show a notable increase in ear damage and a number of surviving older larvae, particularly at southern locations. Assuming recessive resistance, the estimated resistance allele frequencies for Vip3Aa ranged from 0.115 in the Gulf states to 0.032 at more northern locations. These findings indicate that better resistance management practices are urgently needed to sustain efficacy the of corn and cotton that produce Vip3Aa.

Traditional and novel risk factors for incident aortic stenosis in community-dwelling older adults.

OBJECTIVES: Calcific aortic stenosis (AS) is the most common valvular disease in older adults, yet its risk factors remain insufficiently studied in this population. Such studies are necessary to enhance understanding of mechanisms, disease management and therapeutics. METHODS: The Cardiovascular Health Study is a population-based investigation of older adults that completed adjudication of incident AS over long-term follow-up. We evaluated traditional cardiovascular risk factors or disease, as well as novel risk factors from lipid, inflammatory and mineral metabolism pathways, in relation to incident moderate or severe AS (including AS procedures) and clinically significant AS (severe AS, including procedures). RESULTS: Of 5390 participants (age 72.9±5.6 years, 57.6% female, 12.5% black), 287 developed moderate or severe AS, and 175 clinically significant AS, during median follow-up of 13.1 years. After full adjustment, age (HR=1.66 per SD (95% CI=1.45, 1.91)), male sex (HR=1.41 (1.06, 1.87)), diabetes (HR=1.53 (1.10, 2.13)), coronary heart disease (CHD, HR=1.36 (1.01, 1.84)), lipoprotein-associated phospholipase-A2 (LpPLA2) activity (HR=1.21 per SD (1.07, 1.37)) and sCD14 (HR=1.16 per SD (1.01, 1.34)) were associated with incident moderate/severe AS, while black race demonstrated an inverse association (HR=0.40 (0.24, 0.65)), and creatinine-based estimated glomerular filtration rate (eGFRcr) showed a U-shaped relationship. Findings were similar for clinically significant AS, although CHD and sCD14 fell short of significance, but interleukin-(IL) 6 showed a positive association. CONCLUSION: This comprehensive evaluation of risk factors for long-term incidence of AS identified associations for diabetes and prevalent CHD, LpPLA2 activity, sCD14 and IL-6, and eGFRcr. These factors may hold clues to biology, preventive efforts and potential therapeutics for those at highest risk.

Constructive exponential tracking control for mechanical systems via Hamiltonian realization and contraction analysis method.

The conventional tracking control of mechanical systems is generally based on the stabilization of error dynamics and most of the results can only guarantee asymptotic tracking of the desired trajectories. Since error dynamics are generally time-varying, it is very difficult to find appropriate Lyapunov functions or control Lyapunov functions to complete stability analysis and controller design. To address this limitation, the novel constructive exponential tracking control method is proposed to mechanical systems by utilizing the Hamiltonian realization and contraction analysis in this paper. Firstly, based on the Hamiltonian realization and use the structural characteristics of port-Hamiltonian systems, the exponential tracking controllers are constructed for fully actuated and under-actuated mechanical systems by combining the pre-feedback with feedback control. The proposed tracking control strategies can be used to discuss fully actuated and under-actuated mechanical systems in a unified framework. Then the exponential decay-rate of tracking controllers and procedure for selecting control parameters for fully actuated and under-actuated mechanical systems are given. Finally, comparative simulations and experiments are carried out to illustrate the effectiveness and robustness of the proposed control strategy.

Response to insulin glargine 100 U/mL treatment in newly-defined subgroups of type 2 diabetes: Post hoc pooled analysis of insulin-naïve participants from nine randomised clinical trials.

AIMS: To assess insulin glargine 100 U/mL (IGlar-100) treatment outcomes according to newly-defined subgroups of type 2 diabetes mellitus (T2DM). METHODS: Insulin-naïve T2DM participants (n = 2684) from nine randomised clinical trials initiating IGlar-100 were pooled and assigned to subgroups "Mild Age-Related Diabetes (MARD)", "Mild Obesity Diabetes (MOD)", "Severe Insulin Resistant Diabetes (SIRD)", and "Severe Insulin Deficient Diabetes (SIDD)", according to age at onset of diabetes, baseline HbA1c, BMI, and fasting C-peptide using sex-specific nearest centroid approach. HbA1c, FPG, hypoglycemia, insulin dose, and body weight were analysed at baseline and 24 weeks. RESULTS: Subgroup distribution was MARD 15.3 % (n = 411), MOD 39.8 % (n = 1067), SIRD 10.5 % (n = 283), SIDD 34.4 % (n = 923). From baseline HbA1c 8.0-9.6% adjusted least square mean reductions after 24 weeks were similar between subgroups (1.4-1.5 %). SIDD was less likely to achieve HbA1c < 7.0 % (OR: 0.40 [0.29, 0.55]) than MARD. While the final IGlar-100 dose (0.36 U/kg) in MARD was lower than in other subgroups (0.46-0.50 U/kg), it had the highest hypoglycemia risk. SIRD had lowest hypoglycemia risk and SIDD exhibited greatest body weight gain. CONCLUSIONS: IGlar-100 lowered hyperglycemia similarly in all T2DM subgroups, but level of glycemic control, insulin dose, and hypoglycemia risk differed between subgroups.

The TINCR ubiquitin-like microprotein is a tumor suppressor in squamous cell carcinoma.

The TINCR (Terminal differentiation-Induced Non-Coding RNA) gene is selectively expressed in epithelium tissues and is involved in the control of human epidermal differentiation and wound healing. Despite its initial report as a long non-coding RNA, the TINCR locus codes for a highly conserved ubiquitin-like microprotein associated with keratinocyte differentiation. Here we report the identification of TINCR as a tumor suppressor in squamous cell carcinoma (SCC). TINCR is upregulated by UV-induced DNA damage in a TP53-dependent manner in human keratinocytes. Decreased TINCR protein expression is prevalently found in skin and head and neck squamous cell tumors and TINCR expression suppresses the growth of SCC cells in vitro and in vivo. Consistently, Tincr knockout mice show accelerated tumor development following UVB skin carcinogenesis and increased penetrance of invasive SCCs. Finally, genetic analyses identify loss-of-function mutations and deletions encompassing the TINCR gene in SCC clinical samples supporting a tumor suppressor role in human cancer. Altogether, these results demonstrate a role for TINCR as protein coding tumor suppressor gene recurrently lost in squamous cell carcinomas.

Using Plasma Vitellogenin in Loggerhead Sea Turtles to Assess Reproductive Maturation and Estrogen-Like Contaminant Exposure.

Vitellogenin (VTG), an egg yolk precursor, is abnormally produced by male and juvenile oviparous species after exposure to estrogens. Plasma VTG in loggerhead sea turtles (Caretta caretta) helped us understand their reproductive maturation and investigate it as a biomarker of contaminant exposure. The presence of VTG was screened in plasma from 404 loggerheads from the northwestern Atlantic Ocean using a freshwater turtle antibody in western blots. The concentrations of VTG were semiquantified using band intensities calibrated to results from a loggerhead antibody enzyme-linked immunoassay. The detection and concentrations of VTG were in (from highest to lowest): nesting females, in-water adult females, subadult females, smaller females, unknown sex, and males. Loggerheads from this region begin vitellogenesis at ≅77 cm straight carapace length. We classified VTG expression as abnormal in nine male or juvenile turtles. Organochlorine contaminant (OC) concentrations were measured in blood and/or fat biopsies of some turtles. One abnormal VTG female had the second highest fat polychlorinated biphenyl (PCB) and 4,4'-dichlorodiphenyldichloroethylene concentrations compared among 43 VTG-negative juveniles. The nine VTG-abnormal turtles had average blood PCB concentrations 8.5% higher, but not significantly different, than 46 VTG-negative juveniles (p = 0.453). In turtles less than 77 cm, blood PCB concentrations were significantly, but weakly, correlated with semiquantified VTG concentrations (tau = 0.1, p = 0.004). Greater blood OC concentrations were found in adult females than in males, which motivated the creation of a conceptual model of OC, VTG, and hormone concentrations across a reproductive cycle. A decision tree is also provided incorporating VTG as a sexing tool. Abnormal VTG expression cannot conclusively be linked to endocrine disruption caused by these OC concentrations. Studies should further investigate causes of abnormal VTG expression in wild sea turtles. Environ Toxicol Chem 2023;42:1309-1325. © 2023 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.