Application of microphysiological systems for nonclinical evaluation of cell therapies

Microphysiological systems (MPS) are gaining broader application in the pharmaceutical industry but have primarily been leveraged in early discovery toxicology and pharmacology studies with small molecules. The adoption of MPS offers a promising avenue to reduce animal use, improve in-vitro-to-in-vivo translation of pharmacokinetics/pharmacodynamics and toxicity correlation, and provide mechanistic understanding of model species suitability. While MPS have demonstrated utility in these areas with small molecules and biologics, MPS models in cell therapy development have not been fully explored, let alone validated. Distinguishing features of MPS, including long-term viability and physiologically relevant expression of functional enzymes, receptors, and pharmacological targets make them attractive tools for nonclinical characterization. However, there is currently limited published evidence of MPS being utilized to study the disposition, metabolism, pharmacology, and toxicity profiles of cell therapies. This review provides an industry perspective on the nonclinical application of MPS on cell therapies, first with a focus on oncology applications followed by examples in regenerative medicine.

Microphysiological systems (MPS) are advanced cell models, applied in the pharmaceutical industry to characterize novel therapies. While their application in studies of small molecule ther­apies has been very successful, the use of these models to study cell therapies has been limited. Cell therapies consist of cells and are living drugs, often with complex biological mechanisms of action, which can be very challenging to study. However, MPS have several features that make them attractive for studying cell therapies, including possibilities for longer-term studies and the ability to mimic physiologically relevant biological functions. MPS can mimic complex biological systems and processes, as such, the adoption of MPS offers a promising avenue to reduce the use of animals in the characterization of novel therapies. This review provides an industry perspective on current chal­lenges and highlights opportunities for using MPS in the development of cell therapies.

The Influence of Talar Displacement on Articular Contact Mechanics: A 3D Finite Element Analysis Study Using Weightbearing Computed Tomography.

BACKGROUND: Talar displacement is considered the main predictive factor for poor outcomes and the development of post-traumatic osteoarthritis after ankle fractures. Isolated lateral talar translation, as previously studied by Ramsey and Hamilton using carbon powder imprinting, does not fully replicate the multidirectional joint subluxations seen in ankle fractures. The purpose of this study was to analyze the influence of multiple uniplanar talar displacements on tibiotalar contact mechanics utilizing weightbearing computed tomography (WBCT) and finite element analysis (FEA). METHODS: Nineteen subjects (mean age = 37.6 years) with no history of ankle surgery or injury having undergone WBCT arthrogram (n = 1) and WBCT without arthrogram (n = 18) were included. Segmentation of the WBCT images into 3D simulated models of bone and cartilage was performed. Three-dimensional (3D) multiple uniplanar talar displacements were simulated to investigate the respective influence of various uniaxial displacements (including lateral translation, anteroposterior translation, varus-valgus angulation, and external rotation) on the tibiotalar contact mechanics using FEA. Tibiotalar peak contact stress and contact area were modeled for each displacement and its gradations. RESULTS: Our modeling demonstrated that peak contact stress of the talus and tibia increased, whereas contact area decreased, with incremental displacement in all tested directions. Contact stress maps of the talus and tibia were computed for each displacement demonstrating unique patterns of pressure derangement. One millimeter of lateral translation resulted in 14% increase of peak talar contact pressure and a 3% decrease in contact area. CONCLUSION: Our model predicted that with lateral talar translation, there is less noticeable change in tibiotalar contact area compared with prior studies whereas external rotation greater than 12 degrees had the largest effect on peak contact stress predictions. LEVEL OF EVIDENCE: Level V, computational simulation study.

Hallux Valgus Bunion Splint: Surgical Dressing Technique.

BACKGROUND: Hallux valgus is a common condition with a complex etiology resulting in numerous treatment options. Recurrence of the deformity can occur following correction. Surgical technique and possibly also postoperative care play a role in reducing recurrence rates. This article highlights a postoperative surgical dressing technique which allows for semirigid support during the immediate postoperative period. METHODS: A wooden tongue depressor placed along the medial border of the hallux comprises the primary support for the dressing. The rigidity of the tongue depressor allows for the hallux to be drawn toward the depressor, encouraging neutral alignment of the hallux. Dressings are removed 2 weeks postoperatively, with new dressings applied in similar fashion and maintained in place until 6 weeks postoperatively. RESULTS: Based upon our observations, our surgical dressing technique provides sufficient support following hallux valgus correction surgery while being straightforward to replicate without the need for frequent dressing changes. The dressing materials are of negligible cost and are typically readily available. No associated wound complications have been observed. CONCLUSIONS: We present an easily replicable and affordable option for postoperative hallux valgus correction surgical dressings. LEVELS OF EVIDENCE: Level V: Expert Opinion.

A systematic review of the proposed etiologies of the 2021-2022 outbreaks of pediatric acute hepatitis of unknown etiology.

In April 2022, the World Health Organization (WHO) declared a global outbreak of acute hepatitis of unknown etiology (AHUE) with a high risk of severe outcomes, for which various etiologies have been proposed by the literature. This study examines primary reports of pediatric AHUE cases and summarizes the proposed etiologies. This systematic review collected and evaluated published peer-reviewed articles, official data, and clinical reports of AHUE cases that met the WHO working case definition. 19 hypothesized etiologies for AHUE were identified from 36 sources, which fell into eight categories. While human adenovirus (HAdV) infection, viral infection, and immune-mediated responses were commonly suspected as causes of AHUE, no definitive etiology or epidemiological link has been established. However, recent evidence implicates adeno-associated virus-2 (AAV2) as a likely significant contributor. Conducting a comprehensive literature review following outbreaks is necessary for developing responsive strategies and protocols.

Assessing the current and desired levels of training and applied experiences in chronic disease prevention of students during medical school.

INTRODUCTION: Chronic diseases account for approximately 70% of deaths in the U.S. annually. Though physicians are uniquely positioned to provide behavior change counseling for chronic disease prevention, they often lack the necessary training and self-efficacy. This study examined medical student interest in receiving chronic disease prevention training as a formal part of their education as part of an effort to enhance their ability to provide guidance to patients in the future. METHODS: A 23-question, online survey was sent to all undergraduate medical students enrolled in a large medical education program. The survey assessed medical student interest in receiving training related to chronic disease prevention. Survey topics included student awareness of primary prevention programs, perceived importance of receiving training and applied experience in chronic disease prevention, and preferences for how and when to receive this training. RESULTS: Of 793 eligible medical students, 432 completed the survey (54.5%). Overall, 92.4% of students reported receiving formal training in physical activity, public health, nutrition, obesity, smoking cessation, and chronic diseases was of "very high" or "high" importance. Despite this level of importance, students most frequently reported receiving no or 1-5 h of formal training in a number of topics, including physical activity (35.4% and 47.0%, respectively) and nutrition (16.9% and 56.3%, respectively). The level of importance given to public health training was significantly greater across degree type (p = 0.0001) and future specialty (p = 0.03) for MD/MPH students and those interested in primary care, respectively. CONCLUSIONS: While medical students perceive chronic disease prevention as an important topic, most reported receiving little to no formal training. To address the growing prevalence of chronic disease across our society, programs schools should place greater emphasis on integrating training in physical activity, nutrition, and obesity-related content into the medical education curriculum.

Natural Death Versus Known Date-Of-Death: A Qualitative Study of Views on Voluntary Assisted Dying in an Online Course About Death.

The study aimed to describe views on Voluntary Assisted Dying (VAD), gleaned through qualitative analysis of participant responses to a set activity, run during the 2018 'Dying2Learn' Massive Open Online Course (MOOC). Data from 508 participants, most of whom identified as health professionals, were analysed using thematic content analysis, and themes generated. A large proportion of participants discussed their personal views related to VAD, specifically around choice, control, dignity, palliative care and dying at home, medical intervention, societal factors, the impact on those left behind, laws and regulations, dying 'naturally', advance care directives, and being in pain. In this study, participants had many different views on the act itself, often divisive, but also with common concepts such as respecting the choices and decisions of others.

Profiling Secreted miRNA Biomarkers of Chemical-Induced Neurodegeneration in Human iPSC-Derived Neurons.

Elucidation of predictive fluidic biochemical markers to detect and monitor chemical-induced neurodegeneration has been a major challenge due to a lack of understanding of molecular mechanisms driving altered neuronal morphology and function, as well as poor sensitivity in methods to quantify low-level biomarkers in bodily fluids. Here, we evaluated 5 neurotoxicants (acetaminophen [negative control], bisindolylmaleimide-1, colchicine, doxorubicin, paclitaxel, and rotenone) in human-induced pluripotent stem cell-derived neurons to profile secreted microRNAs (miRNAs) at early and late stages of decline in neuronal cell morphology and viability. Based on evaluation of these morphological (neurite outgrowth parameters) and viability (adenosine triphosphate) changes, 2 concentrations of each chemical were selected for analysis in a human 754 miRNA panel: a low concentration with no/minimal effect on cell viability but a significant decrease in neurite outgrowth, and a high concentration with a significant decrease in both endpoints. A total of 39 miRNAs demonstrated significant changes (fold-change ≥ 1.5 or ≤ 0.67, p value < .01) with at least 1 exposure. Further analyses of targets modulated by these miRNAs revealed 38 key messenger RNA targets with roles in neurological dysfunctions, and identified transforming growth factor-beta (TGF-ß) signaling as a commonly enriched pathway. Of the 39 miRNAs, 5 miRNAs, 3 downregulated (miR-20a, miR-30b, and miR-30d) and 3 upregulated (miR-1243 and miR-1305), correlated well with morphological changes induced by multiple neurotoxicants and were notable based on their relationship to various neurodegenerative conditions and/or key pathways, such as TGF-ß signaling. These datasets reveal miRNA candidates that warrant further evaluation as potential safety biomarkers of chemical-induced neurodegeneration.

Targeting Membrane HDM-2 by PNC-27 Induces Necrosis in Leukemia Cells But Not in Normal Hematopoietic Cells.

BACKGROUND/AIM: Anticancer peptide PNC-27 binds to HDM-2 protein on cancer cell membranes inducing the formation of cytotoxic transmembrane pores. Herein, we investigated HDM-2 membrane expression and the effect of PNC-27 treatment on human non-stem cell acute myelogenous leukemia cell lines: U937, acute monocytic leukemia; OCI-AML3, acute myelomonocytic leukemia and HL60, acute promyelocytic leukemia. MATERIALS AND METHODS: We measured cell surface membrane expression of HDM-2 using flow cytometry. Cell viability was assessed using MTT assay while direct cytotoxicity was measured by lactate dehydrogenase (LDH) release and induction of apoptotic markers annexin V and caspase-3. RESULTS: HDM-2 is expressed at high levels in membranes of U937, OCI-AML3 and HL-60 cells. PNC-27 can bind to membrane HDM-2 to induce cell necrosis and LDH release within 4 h. CONCLUSION: Targeting membrane HDM-2 can be a potential strategy to treat leukemia. PNC-27 targeting membrane HDM-2 demonstrated significant anti-leukemia activity in a variety of leukemic cell lines.

A retrospective regional study of aqueduct stenosis and fourth ventricle outflow obstruction in the paediatric complex neurofibromatosis type 1 population; Aetiology, clinical presentation and management.

OBJECTIVES: Aqueduct stenosis (AS) and fourth ventricle outflow obstruction are rare associations of neurofibromatosis type 1 (NF1), resulting in ventriculomegaly and hydrocephalus requiring surgical treatment. This study aims to identify the prevalence of AS and its patterns of clinical presentation, aetiology and treatment in the paediatric complex NF1 population. PATIENTS AND METHODS: Patients with NF-1 aged 0-18 years were recruited from the Regional Genetic Family Register, following institutional review board approval. Magnetic resonance imaging data and clinical documents were reviewed with respect to clinical presentation, degree of ventriculomegaly, aetiological factors and management of AS and fourth ventricle outflow obstruction. RESULTS: 24 of the 233 paediatric patients seen within the NHS highly specialised service for complex NF1 were found to have AS or and fourth ventricle outflow obstruction. This included 13 males and 11 females with a mean age of 9 years 5 months (range 8 months - 17 years). The majority of patients with AS or fourth ventricle outflow obstruction presented with symptoms of raised intracranial pressure associated with ventriculomegaly and/or hydrocephalus (n = 18). However, in 25 % of patients, AS was an incidental finding on MRI and was observed both in the presence (n = 2) and absence (n = 4) of ventriculomegaly. In the majority of cases a single cause of AS was identified (n = 16), of which tectal plate thickening (n = 7) was most frequently observed. The remaining 8 patients had multiple causes of AS, in which tectal plate thickening (n = 7) and aqueductal webs (n = 5) were the most common observations. Surgery was performed on all patients with evidence of raised pressure (n = 8) by performing endoscopic third ventriculostomy (ETV) (n = 5) or ventriculoperitoneal (VP)-shunting (n = 3). Tectal plate thickening was most frequently observed in patients who underwent ETV (n = 3), followed by aqueductal web (n = 1) and T2-signal changes in the tectal plate (n = 1). Patients treated with VP-shunt had 4th ventricle outflow obstruction (n = 2) and a tectal plate tumour (n = 1). CONCLUSION: This study identifies that AS is more prevalent amongst the paediatric complex NF-1 population than previously reported, occurring in 10 % of cases. Our findings demonstrate that AS is most commonly symptomatic in presentation but can be asymptomatic in 25 % of paediatric complex NF1 patients. In this population, AS can occur both in the presence and absence of ventriculomegaly and therefore requires careful monitoring for development of hydrocephalus. In this study, over one third of patients (9 of 24 patients) with AS eventually required treatment.

Perceived fatigue in children and young adults with neurofibromatosis type 1.

AIM: This study describes the prevalence and severity of perceived fatigue in a young neurofibromatosis type 1 (NF1) population. METHODS: Ethical approval was obtained and NF1 affected Individuals aged 2-18 years from the Manchester's NF1 clinic invited along with any unaffected siblings. The PedsQL Multidimensional Fatigue Scale Parental and child report was used. This validated measure explores cognitive, physical and sleep/rest domains on a 0-100 scale. Higher scores indicate less fatigue. Fatigue scores in affected children were compared to unaffected siblings after adjusting for age, sex and Index of Multiple Deprivation and with published population standards using z-scores. RESULTS: A total of 286 families were invited and 75 affected and 16 siblings participated. There were significant differences between NF1 and controls in the aggregated fatigue core (child report 55 ± 19 vs. 75 (14), P < 0.001; parent 54 ± 20 vs. 73 ± 18, P = 0.001) and the three sub-domains: cognitive (child 48 ± 27 vs. 75 ± 23, P < 0.001), physical (child 59 ± 19 vs. 82 ± 14, P < 0.001) and sleep/rest (child 59 ± 19 vs. 71 ± 15, P = 0.018). Similar differences were seen when compared with published controls (aggregated child z-score -1.9 ± 1.4, P < 0.001; parent -3.2 ± 1.8, P < 0.001). Prevalence of severe fatigue indicated by scores <2 standard deviation below published means for healthy controls were also higher for children with NF on both parent and child reports. Agreement between child and parent reports were limited as is frequently seen in the literature. CONCLUSION: This study suggests that children with NF1 are affected by perceived fatigue when compared with healthy children who do not have NF1.

Breast cancer in neurofibromatosis 1: survival and risk of contralateral breast cancer in a five country cohort study.

PURPOSE: Neurofibromatosis 1 (NF1) is an autosomal dominant condition caused by pathogenic variants of the NF1 gene. A markedly increased risk of breast cancer is associated with NF1. We have determined the breast cancer survival and risk of contralateral breast cancer in NF1. METHODS: We included 142 women with NF1 and breast cancer from five cohorts in Europe and 335 women without NF1 screened for other familial breast cancers. Risk of contralateral breast cancer and death were assessed by Kaplan-Meier analysis with delayed entry. RESULTS: One hundred forty-two women with NF1 were diagnosed for breast cancer at a median age of 46.9 years (range 27.0-84.3 years) and then followed up for 1235 person-years (mean = 8.70 years). Twelve women had contralateral breast cancer with a rate of 10.5 per 1000 years. Cumulative risk for contralateral breast cancer was 26.5% in 20 years. Five and 10-year all-cause survival was 64.9% (95% confidence interval [CI] = 54.8-76.8) and 49.8% (95%CI = 39.3-63.0). Breast cancer-specific 10-year survival was 64.2% (95% CI = 53.5-77.0%) compared with 91.2% (95% CI = 87.3-95.2%) in the non-NF1 age-matched population at increased risk of breast cancer. CONCLUSION: Women with NF1 have a substantial contralateral breast cancer incidence and poor survival. Early start of breast cancer screening may be a way to improve the survival.

Correction: Breast cancer in neurofibromatosis 1: survival and risk of contralateral breast cancer in a five country cohort study.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Clinical Presentation and Outcomes of Phaeochromocytomas/Paragangliomas in Neurofibromatosis Type 1.

Introduction: Patients with neurofibromatosis type 1 (NF1) are at risk of developing phaeochromocytomas/paragangliomas (PHAEO/PG). Unlike in other familial PHAEO/PG syndromes, there are no published guidelines regarding screening in asymptomatic or normotensive patients with NF1. This strategy may be associated with preventable morbidities in those patients who ultimately present with symptomatic PHAEO/PG. Objective: To describe the mode of presentation and the incidence of adverse clinical outcomes attributed to PHAEO/PG in NF1. Methods: A retrospective study was performed in a tertiary referral centre in collaboration with a national complex NF1 centre. Hospital records and databases between 1998-2018 were searched. Results: Twenty-seven patients with NF1 and PHAEO/PG were identified. In all but one, PHAEO/PG was diagnosed after NF1. The median age at the time of diagnosis of PHAEO/PG was 43 years (range 22-65) and 21/27 (78%) were females. The diagnosis was mostly incidental in 13/27 (48%) while classical PHAEO/PG symptoms were found in 15/27 (56%), and hypertension was found in 14/27 (52%) of NF1 patients prior to PHAEO/PG diagnosis. No patient had undergone biochemical screening for PHAEO/PG. Metastatic disease was evident in 2/27 patients, 8 suffered potentially avoidable complications attributed to PHAEO/PG (including two deaths). Conclusion: The course of PHAEO/PG in NF1 is associated with an unpredictable presentation and potentially avoidable adverse outcomes. We recommend that routine biochemical screening for PHAEO/PG should be part of the care package offered to all patients with NF1 by regular measurements of plasma free or urinary fractionated metanephrines starting from early adolescence and repeated every 3 years.

Using Collaborative Cross Mouse Population to Fill Data Gaps in Risk Assessment: A Case Study of Population-Based Analysis of Toxicokinetics and Kidney Toxicodynamics of Tetrachloroethylene.

BACKGROUND: Interindividual variability in susceptibility remains poorly characterized for environmental chemicals such as tetrachloroethylene (PERC). Development of population-based experimental models provide a potential approach to fill this critical need in human health risk assessment. OBJECTIVES: In this study, we aimed to better characterize the contribution of glutathione (GSH) conjugation to kidney toxicity of PERC and the degree of associated interindividual toxicokinetic (TK) and toxicodynamic (TD) variability by using the Collaborative Cross (CC) mouse population. METHODS: Male mice from 45 strains were intragastrically dosed with PERC ([Formula: see text]) or vehicle (5% Alkamuls EL-620 in saline), and time-course samples were collected for up to 24 h. Population variability in TK of S-(1,2,2-trichlorovinyl)GSH (TCVG), S-(1,2,2-trichlorovinyl)-L-cysteine (TCVC), and N-acetyl-S-(1,2,2-trichlorovinyl)-L-cysteine (NAcTCVC) was quantified in serum, liver, and kidney, and analyzed using a toxicokinetic model. Effects of PERC on kidney weight, fatty acid metabolism-associated genes [ Acot1 (Acyl-CoA thioesterase 1), Fabp1 (fatty acid-binding protein 1), and Ehhadh (enoyl-coenzyme A, hydratase/3-hydroxyacyl coenzyme A dehydrogenase)], and a marker of proximal tubular injury [KIM-1 (kidney injury molecule-1)/Hepatitis A virus cellular receptor 1 ( Havcr1)] were evaluated. Finally, quantitative data on interstrain variability in both formation of GSH conjugation metabolites of PERC and its kidney effects was used to calculate adjustment factors for the interindividual variability in both TK and TD. RESULTS: Mice treated with PERC had significantly lower kidney weight, higher kidney-to-body weight (BW) ratio, and higher expression of fatty acid metabolism-associated genes ( Acot1, Fabp1, and Ehhadh) and a marker of proximal tubular injury (KIM-1/ Havcr1). Liver levels of TCVG were significantly correlated with KIM-1/ Havcr1 in kidney, consistent with kidney injury being associated with GSH conjugation. We found that the default uncertainty factor for human variability may be marginally adequate to protect 95%, but not more, of the population for kidney toxicity mediated by PERC. DISCUSSION: Overall, this study demonstrates the utility of the CC mouse population in characterizing metabolism-toxicity interactions and quantifying interindividual variability. Further refinement of the characterization of interindividual variability can be accomplished by incorporating these data into in silico population models both for TK (such as a physiologically based pharmacokinetic model), as well as for toxicodynamic responses. https://doi.org/10.1289/EHP5105.

"I want to die in my sleep"-how people think about death, choice, and control: findings from a Massive Open Online Course.

BACKGROUND: Complex social and ethical debates about voluntary assisted dying (euthanasia), palliative care, and advance care planning are presently being worked through in many developed countries, and the policy implications of these discussions for palliative care are potentially very significant. However, community attitudes to death and dying are complex, multilayered, and contain many mixed messages. METHODS: Participants posted comments in a Massive Open Online Course (MOOC) on death and dying, entitled Dying2Learn. This provided an opportunity to explore societal and personal attitudes to wishes and beliefs around death and dying. For one activity in the MOOC, participants responded to a question asking them about "the best way to go". RESULTS: Responses were subjected to thematic analysis, during which they were coded for conceptual categories. This analysis showed how acceptance of death as a natural and normal process, and as a shared event that affects a whole social network, may nonetheless be accompanied by deep reluctance to address the physical process of dying (i.e., "avoidant acceptance"). CONCLUSIONS: Our findings highlighted a desire for choice and control in relation to dying, which is a common element in discussions of both advance care planning and palliative care. This same focus may contribute to a perception that voluntary assisted dying/euthanasia is a necessary strategy for ensuring that people have control over their dying process. We discuss the paradox of individuals wanting to have control whilst preferring not to know that they are dying.

Population-Based Analysis of DNA Damage and Epigenetic Effects of 1,3-Butadiene in the Mouse.

Metabolism of 1,3-butadiene, a known human and rodent carcinogen, results in formation of reactive epoxides, a key event in its carcinogenicity. Although mice exposed to 1,3-butadiene present DNA adducts in all tested tissues, carcinogenicity is limited to liver, lung, and lymphoid tissues. Previous studies demonstrated that strain- and tissue-specific epigenetic effects in response to 1,3-butadiene exposure may influence susceptibly to DNA damage and serve as a potential mechanism of tissue-specific carcinogenicity. This study aimed to investigate interindividual variability in the effects of 1,3-butadiene using a population-based mouse model. Male mice from 20 Collaborative Cross strains were exposed to 0 or 635 ppm 1,3-butadiene by inhalation (6 h/day, 5 days/week) for 2 weeks. We evaluated DNA damage and epigenetic effects in target (lung and liver) and nontarget (kidney) tissues of 1,3-butadiene-induced carcinogenesis. DNA damage was assessed by measuring N-7-(2,3,4-trihydroxybut-1-yl)-guanine (THB-Gua) adducts. To investigate global histone modification alterations, we evaluated the trimethylation and acetylation of histones H3 and H4 across tissues. Changes in global cytosine DNA methylation were evaluated from the levels of methylation of LINE-1 and SINE B1 retrotransposons. We quantified the degree of variation across strains, deriving a chemical-specific human variability factor to address population variability in carcinogenic risk, which is largely ignored in current cancer risk assessment practice. Quantitative trait locus mapping identified four candidate genes related to chromatin remodeling whose variation was associated with interstrain susceptibility. Overall, this study uses 1,3-butadiene to demonstrate how the Collaborative Cross mouse population can be used to identify the mechanisms for and quantify the degree of interindividual variability in tissue-specific effects that are relevant to chemically induced carcinogenesis.

Structured Handover in General Surgery: An Audit of Current Practice.

INTRODUCTION: Verbal handover alone compromises patient safety, and supporting written documents significantly increases retention of information, with printed handover sheets being the best at avoiding data loss. The Royal College of Surgeons (RCS) has produced guidelines on safe handover practice, in which a minimum dataset is recommended for inclusion when handing over patients to incoming surgical teams, and studies have indicated better adherence to these guidelines when preprinted handover proformas are used. METHODS: All surgical handover sessions were attended for a one-week period, and copies of handover sheets were taken. These were analyzed against RCS guidelines on the essential dataset for safe handover practice. A standardized handover sheet, developed in accordance with these guidelines and designed to encourage impartation of this minimum dataset, was then circulated among members of the surgical department and made readily available on wards. After a 6-week period, a postintervention audit was conducted using the same methods. RESULTS: Striking differences were seen in the quality of information handed over preintervention and postintervention. The documentation of patient location increased significantly (56%-87%, P < 0.0001; 95% CI, 0.460-0.151), as did the documentation of important outstanding clinical tasks (45%-89%, P = 0.004; 95% CI, 0.439-0.089). Documentation of blood results increased (P < 0.0001; 95% CI, 0.523-0.226), and the proportion of patients for whom the occurrence of a senior review was documented increased from 28% (18) to 85% (45) (P < 0.0001; 95% CI, 0.717-0.419) CONCLUSIONS: The use of a structured, computer-generated handover proforma significantly improved compliance with RCS guidelines within the surgical department of our hospital, and we recommend its continued use among on-call surgical teams.

Sex-specific differences in genotoxic and epigenetic effects of 1,3-butadiene among mouse tissues.

Exposure to environmental chemicals has been shown to have an impact on the epigenome. One example is a known human carcinogen 1,3-butadiene which acts primarily by a genotoxic mechanism, but also disrupts the chromatin structure by altering patterns of cytosine DNA methylation and histone modifications. Sex-specific differences in 1,3-butadiene-induced genotoxicity and carcinogenicity are well established; however, it remains unknown whether 1,3-butadiene-associated epigenetic alterations are also sex dependent. Therefore, we tested the hypothesis that inhalational exposure to 1,3-butadiene will result in sex-specific epigenetic alterations. DNA damage and epigenetic effects of 1,3-butadiene were evaluated in liver, lung, and kidney tissues of male and female mice of two inbred strains (C57BL/6J and CAST/EiJ). Mice were exposed to 0 or 425 ppm of 1,3-butadiene by inhalation (6 h/day, 5 days/week) for 2 weeks. Strain- and tissue-specific differences in 1,3-butadiene-induced DNA adducts and crosslinks were detected in the liver, lung and kidney; however, significant sex-specific differences in DNA damage were observed in the lung of C57BL/6J mice only. In addition, we assessed expression of the DNA repair genes and observed a marked upregulation of Mgmt in the kidney in female C57BL/6J mice. Sex-specific epigenetic effects of 1,3-butadiene exposure were evident in alterations of cytosine DNA methylation and histone modifications in the liver and lung in both strains. Specifically, we observed a loss of cytosine DNA methylation in the liver and lung of male and female 1,3-butadiene-exposed C57BL/6J mice, whereas hypermethylation was found in the liver and lung in 1,3-butadiene-exposed female CAST/EiJ mice. Our findings suggest that strain- and sex-specific effects of 1,3-butadiene on the epigenome may contribute to the known differences in cancer susceptibility.

Metabolism and Toxicity of Trichloroethylene and Tetrachloroethylene in Cytochrome P450 2E1 Knockout and Humanized Transgenic Mice.

Trichloroethylene (TCE) and tetrachloroethylene (PCE) are structurally similar olefins that can cause liver and kidney toxicity. Adverse effects of these chemicals are associated with metabolism to oxidative and glutathione conjugation moieties. It is thought that CYP2E1 is crucial to the oxidative metabolism of TCE and PCE, and may also play a role in formation of nephrotoxic metabolites; however, inter-species and inter-individual differences in contribution of CYP2E1 to metabolism and toxicity are not well understood. Therefore, the role of CYP2E1 in metabolism and toxic effects of TCE and PCE was investigated using male and female wild-type [129S1/SvlmJ], Cyp2e1(-/-), and humanized Cyp2e1 [hCYP2E1] mice. To fill in existing gaps in our knowledge, we conducted a toxicokinetic study of TCE (600 mg/kg, single dose, i.g.) and a subacute study of PCE (500 mg/kg/day, 5 days, i.g.) in 3 strains. Liver and kidney tissues were subject to profiling of oxidative and glutathione conjugation metabolites of TCE and PCE, as well as toxicity endpoints. The amounts of trichloroacetic acid formed in the liver was hCYP2E1≈ 129S1/SvlmJ > Cyp2e1(-/-) for both TCE and PCE; levels in males were about 2-fold higher than in females. Interestingly, 2- to 3-fold higher levels of conjugation metabolites were observed in TCE-treated Cyp2e1(-/-) mice. PCE induced lipid accumulation only in liver of 129S1/SvlmJ mice. In the kidney, PCE exposure resulted in acute proximal tubule injury in both sexes in all strains (hCYP2E1 ≈ 129S1/SvlmJ > Cyp2e1(-/-)). In conclusion, our results demonstrate that CYP2E1 is an important, but not exclusive actor in the oxidative metabolism and toxicity of TCE and PCE.

Tissue- and strain-specific effects of a genotoxic carcinogen 1,3-butadiene on chromatin and transcription.

Epigenetic effects of environmental chemicals are under intense investigation to fill existing knowledge gaps between environmental/occupational exposures and adverse health outcomes. Chromatin accessibility is one prominent mechanism of epigenetic control of transcription, and understanding of the chemical effects on both could inform the causal role of epigenetic alterations in disease mechanisms. In this study, we hypothesized that baseline variability in chromatin organization and transcription profiles among various tissues and mouse strains influence the outcome of exposure to the DNA damaging chemical 1,3-butadiene. To test this hypothesis, we evaluated DNA damage along with comprehensive quantification of RNA transcripts (RNA-seq), identification of accessible chromatin (ATAC-seq), and characterization of regions with histone modifications associated with active transcription (ChIP-seq for acetylation at histone 3 lysine 27, H3K27ac). We collected these data in the lung, liver, and kidney of mice from two genetically divergent strains, C57BL/6J and CAST/EiJ, that were exposed to clean air or to 1,3-butadiene (~600 ppm) for 2 weeks. We found that tissue effects dominate differences in both gene expression and chromatin states, followed by strain effects. At baseline, xenobiotic metabolism was consistently more active in CAST/EiJ, while immune system pathways were more active in C57BL/6J across tissues. Surprisingly, even though all three tissues in both strains harbored butadiene-induced DNA damage, little transcriptional effect of butadiene was observed in liver and kidney. Toxicologically relevant effects of butadiene in the lung were on the pathways of xenobiotic metabolism and inflammation. We also found that variability in chromatin accessibility across individuals (i.e., strains) only partially explains the variability in transcription. This study showed that variation in the basal states of epigenome and transcriptome may be useful indicators for individuals or tissues susceptible to genotoxic environmental chemicals.