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Mercury is a contaminant of global concern. It is transported in the atmosphere primarily as gaseous elemental mercury, but its reactivity and deposition to the surface environment, through which it enters the aquatic food chain, is greatly enhanced following oxidation. Measurements and modelling studies of oxidised mercury in the polar to subtropical marine boundary layer (MBL) have suggested that photolytically produced bromine atoms are the primary oxidant of mercury. We report year-round measurements of elemental and oxidised mercury, along with ozone, halogen oxides (IO and BrO) and nitrogen oxides (NO2), in the MBL over the Galápagos Islands in the equatorial Pacific. Elemental mercury concentration remained low throughout the year, while higher than expected levels of oxidised mercury occurred around midday. Our results show that the production of oxidised mercury in the tropical MBL cannot be accounted for by bromine oxidation only, or by the inclusion of ozone and hydroxyl. As a two-step oxidation mechanism, where the HgBr intermediate is further oxidised to Hg(II), depends critically on the stability of HgBr, an additional oxi-dant is needed to react with HgBr to explain more than 50 % of the observed oxidised mercury. Based on best available thermodynamic data, we show that atomic iodine, NO2, or HO2 could all play the potential role of the missing oxidant, though their relative importance cannot be determined explicitly at this time due to the uncertainties associated with mercury oxidation kinetics. We conclude that the key pathway that significantly enhances atmospheric mercury oxidation and deposition to the tropical oceans is missing from the current understanding of atmospheric mercury oxidation. [ABSTRACT FROM AUTHOR]

Mercury is a contaminant of global concern. It is transported in the atmosphere primarily as gaseous elemental mercury, but its reactivity and deposition to the surface environment, through which it enters the aquatic food chain, is greatly enhanced following oxidation. Measurements of oxidised mercury in the polar to sub-tropical marine boundary layer have suggested that photolytically produced bromine atoms are the primary oxidant of mercury. We report year-round measurements of elemental and oxidised mercury, along with ozone, halogen oxides (IO and BrO) and nitrogen oxides (NO2), in the marine boundary layer over the Galápagos Islands in the Equatorial Pacific. Elemental mercury concentration remained low throughout the year, while considerable concentrations of oxidised mercury occurred around midday. Our results show that the production of oxidised mercury in the tropical marine boundary layer cannot be accounted for by only bromine oxidation, or by the inclusion of ozone and hydroxyl. A two-step oxidation mechanism where the HgBr intermediate is further oxidised to Hg(II) depends critically on the stability of HgBr. If the current paradigm is considered, another oxidant is needed to explain more than 50% of the observed oxidised mercury. We show that atomic iodine could play the role of the missing oxidant, explaining not only the Hg(II) levels observed, but also the daily variability. However, more recent theoretical calculations indicate that the thermal dissociation rate of HgBr is much faster, by an order of magnitude, than previously reported, which implies that only trace gases at relatively high mixing ratios forming stable complexes with HgBr (such as HO2 and NO2) could compete to generate levels of Hg(II) similar to those observed in our study. Nevertheless, the daily variability of oxidised mercury is not well accounted for by using these new theoretically estimated rates. Furthermore, correlation analysis does not support a major role of NO2 or HO2. We conclude that the key pathway that significantly enhances atmospheric mercury oxidation and deposition to the tropical oceans is missing from the current understanding of atmospheric mercury oxidation. [ABSTRACT FROM AUTHOR]

Iodine monoxide (IO) was retrieved using a new multi-axis DOAS instrument deployed at the Izaña subtropical observatory as part of the Network for the Detection of Atmospheric Composition Change (NDACC) programme. The station is located at 2370 m a.s.l., well above the trade wind inversion that limits the top of the marine boundary layer, and is hence representative of the free troposphere. We report daily observations from May to August 2010 at different viewing angles. During this period, the spectral signature of IO was unequivocally detected on every day of measurement. mean IO differential slant column density (DSCD) of 1.2 x 1013 molecules cm-2 was observed at 5° instrument elevation angle (IEA) on clear days using a single zenith reference for the reported period, with a day-to-day variability of 12% at 1 standard deviation. At an IEA of 0°, the mean DSCD value for clear days is 2.0 x 1013 molecules cm-2, with a day-to-day variability of 14%. Based on simultaneous O4 measurements, the IO mixing ratio is estimated to be 0.18 pptv in the free troposphere at an IEA of 5°. Episodes of Saharan dust outbreaks were also observed, with large increases in the DSCDs at higher elevation angles, suggesting an enhancement of IO inside the dust cloud. [ABSTRACT FROM AUTHOR]

Reports on the results of an investigation of carbon monoxide alarm systems in Mecklenburg County, conducted by local authorities. Information on a public health ordinance amended by Mecklenburg County, North Carolina requiring a carbon monoxide alarm with battery back-ups in the majority of residences to prevent poisoning during a power outage; Estimated number of persons that die from unintentional carbon monoxide poisoning in the U.S. each year; Cases of symptomatic carbon monoxide poisoning reported in the county in December 2002 after an ice storm.

Context: Abusive head trauma (AHT) is a dangerous form of child abuse that can be difficult to diagnose in young children.Objectives: To determine how frequently AHT was previously missed by physicians in a group of abused children with head injuries and to determine factors associated with the unrecognized diagnosis.Design: Retrospective chart review of cases of head trauma presenting between January 1, 1990, and December 31, 1995.Setting: Academic children's hospital.Patients: One hundred seventy-three children younger than 3 years with head injuries caused by abuse.Main Outcome Measures: Characteristics of head-injured children in whom diagnosis of AHT was unrecognized and the consequences of the missed diagnoses.Results: Fifty-four (31.2%) of 173 abused children with head injuries had been seen by physicians after AHT and the diagnosis was not recognized. The mean time to correct diagnosis among these children was 7 days (range, 0-189 days). Abusive head trauma was more likely to be unrecognized in very young white children from intact families and in children without respiratory compromise or seizures. In 7 of the children with unrecognized AHT, misinterpretation of radiological studies contributed to the delay in diagnosis. Fifteen children (27.8%) were reinjured after the missed diagnosis. Twenty-two (40.7%) experienced medical complications related to the missed diagnosis. Four of 5 deaths in the group with unrecognized AHT might have been prevented by earlier recognition of abuse.Conclusion: Although diagnosing head trauma can be difficult in the absence of a history, it is important to consider inflicted head trauma in infants and young children presenting with nonspecific clinical signs. [ABSTRACT FROM AUTHOR]

This section presents an abstract of the research paper "Evaluation of the FDA Derived Intervention Levels and the Exposure Rate of 0.4 μR h-1 Using NARAC Web Atmosphere and Diffusion Modeling System," by T. R. Hay, K. A. Higley, and D. M. Hamby.

Background: Predictive models show promise in healthcare, but their successful deployment is challenging due to limited generalizability. Current external validation often focuses on model performance with restricted feature use from the original training data, lacking insights into their suitability at external sites. Our study introduces an innovative methodology for evaluating features during both the development phase and the validation, focusing on creating and validating predictive models for post-surgery patient outcomes with improved generalizability., Methods: Electronic health records (EHRs) from 4 countries (United States, United Kingdom, Finland, and Korea) were mapped to the OMOP Common Data Model (CDM), 2008-2019. Machine learning (ML) models were developed to predict post-surgery prolonged opioid use (POU) risks using data collected 6 months before surgery. Both local and cross-site feature selection methods were applied in the development and external validation datasets. Models were developed using Observational Health Data Sciences and Informatics (OHDSI) tools and validated on separate patient cohorts., Results: Model development included 41 929 patients, 14.6% with POU. The external validation included 31 932 (UK), 23 100 (US), 7295 (Korea), and 3934 (Finland) patients with POU of 44.2%, 22.0%, 15.8%, and 21.8%, respectively. The top-performing model, Lasso logistic regression, achieved an area under the receiver operating characteristic curve (AUROC) of 0.75 during local validation and 0.69 (SD = 0.02) (averaged) in external validation. Models trained with cross-site feature selection significantly outperformed those using only features from the development site through external validation (P < .05)., Conclusions: Using EHRs across four countries mapped to the OMOP CDM, we developed generalizable predictive models for POU. Our approach demonstrates the significant impact of cross-site feature selection in improving model performance, underscoring the importance of incorporating diverse feature sets from various clinical settings to enhance the generalizability and utility of predictive healthcare models., (© The Author(s) 2024. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Background: Bacterial cancer therapy was first trialled in patients at the end of the nineteenth century. More recently, tumour-targeting bacteria have been harnessed to deliver plasmid-expressed therapeutic interfering RNA to a range of solid tumours. A major limitation to clinical translation of this is the short-term nature of RNA interference in vivo due to plasmid instability. To overcome this, we sought to develop tumour-targeting attenuated bacteria that stably express shRNA by virtue of integration of an expression cassette within the bacterial chromosome and demonstrate therapeutic efficacy in vitro and in vivo., Results: The attenuated tumour targeting Salmonella typhimurium SL7207 strain was modified to carry chromosomally integrated shRNA expression cassettes at the xylA locus. The colorectal cancer cell lines SW480, HCT116 and breast cancer cell line MCF7 were used to demonstrate the ability of these modified strains to perform intracellular infection and deliver effective RNA and protein knockdown of the target gene c-Myc. In vivo therapeutic efficacy was demonstrated using the Lgr5creER T2 Apc flx/flx and BlgCreBrca2 flx/fl p53 flx/flx orthotopic immunocompetent mouse models of colorectal and breast cancer, respectively. In vitro co-cultures of breast and colorectal cancer cell lines with modified SL7207 demonstrated a significant 50-95% (P < 0.01) reduction in RNA and protein expression with SL7207/c-Myc targeted strains. In vivo, following establishment of tumour tissue, a single intra-peritoneal administration of 1 × 10 6 CFU of SL7207/c-Myc was sufficient to permit tumour colonisation and significantly extend survival with no overt toxicity in control animals., Conclusions: In summary we have demonstrated that tumour tropic bacteria can be modified to safely deliver therapeutic levels of gene knockdown. This technology has the potential to specifically target primary and secondary solid tumours with personalised therapeutic payloads, providing new multi-cancer detection and treatment options with minimal off-target effects. Further understanding of the tropism mechanisms and impact on host immunity and microbiome is required to progress to clinical translation., (© 2024. The Author(s).)

LYN kinase is expressed in BRCA1 loss-of-function-dependent mouse mammary tumours, in the cells of origin of such tumours, and in human breast cancer. Suppressing LYN kinase activity in BRCA1-defective cell lines as well as in in vitro cultures of Brca1-null mouse mammary tumours is deleterious to their growth. Here, we examined the interaction between LYN kinase and BRCA1 loss-of-function in an in vivo mouse mammary tumour model, using conditional knockout Brca1 and Lyn alleles. Comparison of Brca1 tumour cohorts showed little difference in mammary tumour formation between animals that were wild type, heterozygous or homozygous for the conditional Lyn allele, although this was confounded by factors including incomplete Lyn recombination in some tumours. RNA-sequencing analysis demonstrated that tumours with high levels of Lyn gene expression had a slower doubling time, but this was not correlated with levels of LYN staining in tumour cells themselves. Rather, high Lyn expression and slower tumour growth were likely a result of B-cell infiltration. The multifaceted role of LYN indicates that it is likely to present difficulties as a therapeutic target in breast cancer., Competing Interests: Competing interests The authors declare no competing or financial interests., (© 2024. Published by The Company of Biologists Ltd.)

A better understanding of the mechanisms generating tumour heterogeneity will allow better targeting of current therapies, identify potential resistance mechanisms and highlight new approaches for therapy. We have previously shown that in genetically modified mouse models carrying conditional oncogenic alleles, mammary tumour histotype varies depending on the combination of alleles, the cell type to which they are targeted and, in some cases, reproductive history. This suggests that tumour heterogeneity is not a purely stochastic process; rather, differential activation of signalling pathways leads to reproducible differences in tumour histotype. We propose the NOTCH signalling pathway as one such pathway. Here, we have crossed conditional knockout Notch1 or Notch2 alleles into an established mouse mammary tumour model. Notch1/2 deletion had no effect on tumour-specific survival; however, loss of Notch alleles resulted in a dose-dependent increase in metaplastic adenosquamous carcinomas (ASQCs). ASQCs and adenomyoepitheliomas (AMEs) also demonstrated a significant increase in AKT signalling independent of Notch status. Therefore, the NOTCH pathway is a suppressor of the ASQC phenotype, while increased PI3K/AKT signalling is associated with ASQC and AME tumours. We propose a model in which PI3K/AKT and NOTCH signalling act interact to determine mouse mammary tumour histotype.

Purpose: Supplementing investigator-specified variables with large numbers of empirically identified features that collectively serve as 'proxies' for unspecified or unmeasured factors can often improve confounding control in studies utilizing administrative healthcare databases. Consequently, there has been a recent focus on the development of data-driven methods for high-dimensional proxy confounder adjustment in pharmacoepidemiologic research. In this paper, we survey current approaches and recent advancements for high-dimensional proxy confounder adjustment in healthcare database studies., Methods: We discuss considerations underpinning three areas for high-dimensional proxy confounder adjustment: (1) feature generation-transforming raw data into covariates (or features) to be used for proxy adjustment; (2) covariate prioritization, selection, and adjustment; and (3) diagnostic assessment. We discuss challenges and avenues of future development within each area., Results: There is a large literature on methods for high-dimensional confounder prioritization/selection, but relatively little has been written on best practices for feature generation and diagnostic assessment. Consequently, these areas have particular limitations and challenges., Conclusions: There is a growing body of evidence showing that machine-learning algorithms for high-dimensional proxy-confounder adjustment can supplement investigator-specified variables to improve confounding control compared to adjustment based on investigator-specified variables alone. However, more research is needed on best practices for feature generation and diagnostic assessment when applying methods for high-dimensional proxy confounder adjustment in pharmacoepidemiologic studies., (© 2022 The Authors. Pharmacoepidemiology and Drug Safety published by John Wiley & Sons Ltd.)

P-glycoprotein (P-gp, MDR1) is expressed at the blood-brain barrier (BBB) and restricts penetration of its substrates into the central nervous system (CNS). In vitro MDR1 assays are frequently used to predict the in vivo relevance of MDR1-mediated efflux at the BBB. It has been well established that drug candidates with high MDR1 efflux ratios (ERs) display poor CNS penetration. Following a comparison of MDR1 transporter function between the MDR1-MDCKI cell line from National Institutes of Health (NIH) and our internal MDR1-MDCKII cell line, the former was found to provide better predictions of in vivo brain penetration than our in-house MDR1-MDCKII cell line. In particular, the NIH MDR1 assay has an improved sensitivity to differentiate the compounds with ERs of <3 in our internal cell line and is able to reduce the risk of false negatives. A better correlation between NIH MDR1 ERs and brain penetration in rat and non-human primate (NHP) was demonstrated. Additionally, a comparison of brain penetration time course of MDR1 substrates and an MDR1 non-substrate in NHP demonstrated that MDR1 interaction can delay the time to equilibrium of drug concentration in the brain with plasma. It is recommended to select highly permeable compounds without MDR1 interaction for rapid brain penetration to produce the maximal pharmacological effect in the CNS with a quicker onset., (© 2022 The Authors. Pharmacology Research & Perspectives published by John Wiley & Sons Ltd, British Pharmacological Society and American Society for Pharmacology and Experimental Therapeutics.)

Objective: Paramedics are at the forefront of emergency healthcare. Quick and careful decision making is required to effectively care for their patients; however, excessive sleepiness has the potential to impact on clinical decision making. Studies investigating the effects of night shift work on sleepiness, cognitive function and clinical performance in the prehospital setting are limited. Here, we aimed to determine the extent to which sleepiness is experienced over the course of a simulation-based 13-hour night shift and how this impacts on clinical performance and reaction time., Methods: Twenty-four second year paramedic students undertook a 13-hour night shift simulation study in August 2017. The study consisted of 10 real-to-life clinical scenarios. Sleepiness, perceived workload and motivation were self-reported, and clinical performance graded for each scenario. Reaction time, visual attention and task switching were also evaluated following each block of two scenarios., Results: The accuracy of participants' clinical decision making declined significantly over the 13-hour night shift simulation. This was accompanied by an increase in sleepiness and a steady decline in motivation. Participants performed significantly better on the cognitive flexibility task across the duration of the simulated night shift and no changes were observed on the reaction time task. Perceived workload varied across the course of the night., Conclusion: Overall, increased sleepiness and decreased clinical decision making were noted towards the end of the 13-hour simulated night shift. It is unclear the extent to which these results are reflective of practising paramedics who have endured several years of night shift work, however, this could have serious implications for patient outcomes and warrants further investigation., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.)

Objective: To determine the frequency, indications and complications associated with the use of faecal diversion systems (rectal tubes) in critically ill patients., Design: A single centre observational study over 15 months., Setting: Intensive care unit (ICU)., Participants: Patients admitted during this period., Main Outcome Measures: Frequency of rectal tubes utilisation in ICU, as well as associated adverse events, with major events defined as lower gastrointestinal bleeding associated with defined blood transfusion of two or more units of red cells or endoscopy or surgical intervention., Results: Of 3418 admission episodes, there were 111 episodes of rectal tubes inserted in 99 patients. Rectal tubes remained indwelling for a median of 5 days (range, 1-23) for a total of 641 patient-days. The most frequent indication for insertion was excessive bowel motions. A major adverse event was observed in three patients (3%; 0.5 events per 100 device days). Two patients underwent laparotomy and one patient sigmoidoscopy. These patients received between two and 23 units of packed red blood cells. Patients who had a rectal tube inserted had a substantially greater duration of ICU admission (mean, 14 days [SD, 14] v 2.8 days [SD, 3.7]) and hospital mortality (15% v 7.7%; risk ratio, 2.0; 95% CI, 1.2-3.4) as well as an overall higher Australian and New Zealand Risk of Death (ANZROD) score (mean, 27 [SD, 22] v 12.6 [SD, 20])., Conclusion: Rectal tubes appear to be frequently inserted and can lead to major adverse events in critically ill patients.

Competing Interests: Competing interests: None declared.

Patients with chronic pain commonly believe their pain is related to the weather. Scientific evidence to support their beliefs is inconclusive, in part due to difficulties in getting a large dataset of patients frequently recording their pain symptoms during a variety of weather conditions. Smartphones allow the opportunity to collect data to overcome these difficulties. Our study Cloudy with a Chance of Pain analysed daily data from 2658 patients collected over a 15-month period. The analysis demonstrated significant yet modest relationships between pain and relative humidity, pressure and wind speed, with correlations remaining even when accounting for mood and physical activity. This research highlights how citizen-science experiments can collect large datasets on real-world populations to address long-standing health questions. These results will act as a starting point for a future system for patients to better manage their health through pain forecasts., Competing Interests: Competing interestsW.G.D. has received consultancy fees from Bayer Pharmaceuticals and Google, unrelated to this study. B.J. and B.H. are co-founders of uMotif. All other authors declare no competing interests., (© The Author(s) 2019.)

Purpose: Prophylactic laxative regimens may prevent constipation but may increase diarrhea and subsequent rectal tube insertion. Our aim was to compare three prophylactic laxative regimens on the rate of rectal tube insertion (primary outcome) and major constipation- or diarrhea-associated complications., Material and Methods: We conducted a cluster-crossover trial. Three pods in a single ICU were each randomized to one of three regimens for four months with rolling cross-over. All mechanically-ventilated and enterally-fed adult patients received either regimen: A) one coloxyl with senna BD from day one; B) two coloxyl with senna +20 ml lactulose BD commencing on day 3; or C) two coloxyl with senna tablets +20 ml lactulose BD commencing on day 6., Results: We enrolled 570 patients (A = 170, B = 205, C = 195) with similar baseline features. Overall, 53 (9.3%) patients received a rectal tube, and insertion rate was not statistically different between the three regimens (A = 12.9%, B = 7.8%, C = 7.7%; p = 0.15). The proportions of patients with other major constipation- or diarrhea-associated complications were similar, as were major patient-centred outcomes., Conclusion: Earlier commencement of a prophylactic coloxyl-based laxative regimen (day 1 or 3) did not affect the rates of complications associated with constipation or diarrhea when compared to delayed introduction (day 6)., (Copyright © 2019. Published by Elsevier Inc.)

Introduction: Prophylactic laxative bowel regimens may prevent constipation in enterally-fed critically ill patients. However, their use may also increase diarrhea. We performed a systematic review to: 1. Explore the epidemiology of constipation and/or diarrhea in critically ill patients; and 2. Appraise trials evaluating prophylactic laxative bowel regimens., Methods: We searched MEDLINE, Embase, and CINAHL for publications that reported constipation or diarrhea in critically ill adult patients and/or prophylactic laxative bowel regimens., Results: The proportion of critically ill patients experiencing constipation was reported between 20% and 83% and the proportion experiencing diarrhea was reported between 3.3% and 78%. Six studies of prophylactic laxative bowel regimens were identified but only 3 randomised controlled trials were identified, and these were subjected to meta-analysis. Compared with placebo, a prophylactic laxative bowel regimen increased the risk of diarrhea (RR 1.58, 95% CI 1.22 to 2.04) but did not reduce the risk of constipation (RR 0.39, 95% CI 0.14 to 1.05), and did not affect the duration of mechanical ventilation, duration of ICU admission, or mortality., Conclusions: Constipation and diarrhea occur frequently in the critically ill but data evaluating prophylactic laxative bowel regimens in such patients are sparse and do not support their use., (Copyright © 2019. Published by Elsevier Inc.)

Background: Canonical WNT signalling plays a critical role in the regulation of ovarian development; mis-regulation of this key pathway in the adult ovary is associated with subfertility and tumourigenesis. The roles of Adenomatous polyposis coli 2 (APC2), a little-studied WNT signalling pathway regulator, in ovarian homeostasis, fertility and tumourigenesis have not previously been explored. Here, we demonstrate essential roles of APC2 in regulating ovarian WNT signalling and ovarian homeostasis., Methods: A detailed analysis of ovarian histology, gene expression, ovulation and hormone levels was carried out in 10 week old and in aged constitutive APC2-knockout (Apc2 -/- ) mice (mixed background). Statistical significance for qRT-PCR data was determined from 95% confidence intervals. Significance testing was performed using 2-tailed Student's t-test, when 2 experimental cohorts were compared. When more were compared, ANOVA test was used, followed by a post-hoc test (LSD or Games-Howell). P-values of < 0.05 were considered statistically significant., Results: APC2-deficiency resulted in activation of ovarian WNT signalling and sub-fertility driven by intra-ovarian defects. Follicular growth was perturbed, resulting in a reduced rate of ovulation and corpora lutea formation, which could not be rescued by administration of gonadotrophins. Defects in steroidogenesis and follicular vascularity contributed to the subfertility phenotype. Tumour incidence was assessed in aged APC2-deficient mice, which also carried a hypomorphic Apc allele. APC2-deficiency in these mice resulted in predisposition to granulosa cell tumour (GCT) formation, accompanied by acute tumour-associated WNT-signalling activation and a histologic pattern and molecular signature seen in human adult GCTs., Conclusions: Our work adds APC2 to the growing list of WNT-signalling members that regulate ovarian homeostasis, fertility and suppress GCT formation. Importantly, given that the APC2-deficient mouse develops tumours that recapitulate the molecular signature and histological features of human adult GCTs, this mouse has excellent potential as a pre-clinical model to study ovarian subfertility and transitioning to GCT, tumour biology and for therapeutic testing.

Exposure of wild-type (WT) Pseudomonas aeruginosa PAO1 to ZnCl2 (Zn) yielded a concentration-dependent increase in depolarization of the cytoplasmic membrane (CM), an indication that this metal is membrane-damaging. Consistent with this, Zn activated the AmgRS envelope stress-responsive two-component system (TCS) that was previously shown to be activated by and to protect P. aeruginosa from the membrane-damaging effects of aminoglycoside (AG) antibiotics. A mutant lacking amgR showed enhanced Zn-promoted CM perturbation and was Zn-sensitive, an indication that the TCS protected cells from the CM-damaging effects of this metal. In agreement with this, a mutant carrying an AmgRS-activating amgS mutation was less susceptible to Zn-promoted CM perturbation and more tolerant of elevated levels of Zn than WT. AG activation of AmgRS is known to drive expression of the AG resistance-promoting mexXY multidrug efflux operon, and while Zn similarly induced mexXY expression this was independent of AmgRS and reliant on a second TCS implicated in mexXY regulation, ParRS. MexXY did not, however, contribute to Zn resistance or protection from Zn-promoted CM damage. Despite its activation of AmgRS and induction of mexXY, Zn had a minimal impact on the AG resistance of WT P. aeruginosa although, given that Zn-tolerant AmgRS-activated amgS mutant strains are AG resistant, there is still the prospect of this metal promoting AG resistance development in this organism.

Tumours defective in the DNA homologous recombination repair pathway can be effectively treated with poly (ADP-ribose) polymerase (PARP) inhibitors; these have proven effective in clinical trials in patients with BRCA gene function-defective cancers. However, resistance observed in both pre-clinical and clinical studies is likely to impact on this treatment strategy. Over-expression of phosphoglycoprotein (P-gp) has been previously suggested as a mechanism of resistance to the PARP inhibitor olaparib in mouse models of Brca1/2 -mutant breast cancer. Here, we report that in a Brca2 model treated with olaparib, P-gp upregulation is observed but is not sufficient to confer resistance. Furthermore, resistant/relapsed tumours do not show substantial changes in PK/PD of olaparib, do not downregulate PARP1 or re-establish double stranded DNA break repair by homologous recombination, all previously suggested as mechanisms of resistance. However, resistance is strongly associated with epithelial-mesenchymal transition (EMT) and treatment-naïve tumours given a single dose of olaparib upregulate EMT markers within one hour. Therefore, in this model, olaparib resistance is likely a product of an as-yet unidentified mechanism associated with rapid transition to the mesenchymal phenotype., Competing Interests: CONFLICTS OF INTEREST RM, UP, AH, OD, SP, JD, EC, EL and MO are employees of AstraZeneca.

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Cancer cells lose homeostatic flexibility because of mutations and dysregulated signaling pathways involved in maintaining homeostasis. Tuberous Sclerosis Complex 1 (TSC1) and TSC2 play a fundamental role in cell homeostasis, where signal transduction through TSC1/TSC2 is often compromised in cancer, leading to aberrant activation of mechanistic target of rapamycin complex 1 (mTORC1). mTORC1 hyperactivation increases the basal level of endoplasmic reticulum (ER) stress via an accumulation of unfolded protein, due to heightened de novo protein translation and repression of autophagy. We exploit this intrinsic vulnerability of tumor cells lacking TSC2, by treating with nelvinavir to further enhance ER stress while inhibiting the proteasome with bortezomib to prevent effective protein removal. We show that TSC2-deficient cells are highly dependent on the proteosomal degradation pathway for survival. Combined treatment with nelfinavir and bortezomib at clinically relevant drug concentrations show synergy in selectively killing TSC2-deficient cells with limited toxicity in control cells. This drug combination inhibited tumor formation in xenograft mouse models and patient-derived cell models of TSC and caused tumor spheroid death in 3D culture. Importantly, 3D culture assays differentiated between the cytostatic effects of the mTORC1 inhibitor, rapamycin, and the cytotoxic effects of the nelfinavir/bortezomib combination. Through RNA sequencing, we determined that nelfinavir and bortezomib tip the balance of ER protein homeostasis of the already ER-stressed TSC2-deficient cells in favor of cell death. These findings have clinical relevance in stratified medicine to treat tumors that have compromised signaling through TSC and are inflexible in their capacity to restore ER homeostasis.

Liver injury results in rapid regeneration through hepatocyte proliferation and hypertrophy. However, after acute severe injury, such as acetaminophen poisoning, effective regeneration may fail. We investigated how senescence may underlie this regenerative failure. In human acute liver disease, and murine models, p21-dependent hepatocellular senescence was proportionate to disease severity and was associated with impaired regeneration. In an acetaminophen injury mouse model, a transcriptional signature associated with the induction of paracrine senescence was observed within 24 hours and was followed by one of impaired proliferation. In mouse genetic models of hepatocyte injury and senescence, we observed transmission of senescence to local uninjured hepatocytes. Spread of senescence depended on macrophage-derived transforming growth factor-β1 (TGFβ1) ligand. In acetaminophen poisoning, inhibition of TGFβ receptor 1 (TGFβR1) improved mouse survival. TGFβR1 inhibition reduced senescence and enhanced liver regeneration even when delivered beyond the therapeutic window for treating acetaminophen poisoning. This mechanism, in which injury-induced senescence impairs liver regeneration, is an attractive therapeutic target for developing treatments for acute liver failure., (Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.)

Background: Patients with a serious mental illness often receive care that is fragmented due to reduced availability of or access to resources, and inadequate, discontinuous, and uncoordinated care across health, social services, and criminal justice organizations. This article describes the creation of a multisystem analysis that derives insights from an integrated dataset including patient access to case management services, medical services, and interactions with the criminal justice system., Methods: Data were combined from electronic systems within a US mental health ecosystem that included mental health and substance abuse services, as well as data from the criminal justice system. Cox models were applied to test the associations between delivery of services and re-incarceration. Additionally, machine learning was used to train and validate a predictive model to examine effects of non-modifiable risk factors (age, past arrests, mental health diagnosis) and modifiable risk factors (outpatient, medical and case management services, and use of a jail diversion program) on re-arrest outcome., Results: An association was found between past arrests and admission to crisis stabilization services in this population (N = 10,307). Delivery of case management or medical services provided after release from jail was associated with a reduced risk for re-arrest. Predictive models linked non-modifiable and modifiable risk factors and outcomes and predicted the probability of re-arrests with fair accuracy (area under the receiver operating characteristic curve of 0.67)., Conclusions: By modeling the complex interactions between risk factors, service delivery, and outcomes, systems of care might be better enabled to meet patient needs and improve outcomes.