In Vitro-In Vivo Extrapolation of Hepatic Biotransformation Data for Fish. III. An In-depth Case Study with Pyrene.

Computational models that predict chemical bioaccumulation in fish generally account for biotransformation using an apparent first-order whole-body rate constant (kB ; d-1 ). The use of such models requires, therefore, that methods exist for estimating kB , ideally without the need to expose live animals. One promising approach for estimating kB involves the extrapolation of measured in vitro intrinsic clearance (CLIN VITRO,INT ) to the whole animal (in vitro-in vivo extrapolation, [IVIVE]). To date, however, the accuracy of such predictions has been difficult to assess due to uncertainties associated with one or more extrapolation factors and/or a mismatch between fish used to generate in vitro data and those used to conduct in vivo exposures. In the present study we employed a combined in vitro and in vivo experimental approach to evaluate the IVIVE procedure using pyrene (PYR) as a model chemical. To the extent possible, measured rates of CLIN VITRO,INT were extrapolated to estimates of kB using extrapolation factors based on measured values. In vitro material (liver S9 fraction) was obtained from fish exposed to PYR in a controlled bioconcentration study protocol. Fish from the same study were then used to estimate in vivo kB values from an analysis of chemical depuration data. Averaged across four study groups, kB values estimated by IVIVE underestimated those determined from in vivo data by 2.6-fold. This difference corresponds to a 4.1-fold underestimation of true in vivo intrinsic clearance, assuming the liver is the only site of biotransformation. These findings are consistent with previous work performed using mammals and have important implications for use of measured CLIN VITRO,INT values in bioaccumulation assessments with fish. Environ Toxicol Chem 2023;42:1501-1515. Published 2023. This article is a U.S. Government work and is in the public domain in the USA.

Effect of stroke early supported discharge on length of hospital stay: analysis from a national stroke registry.

OBJECTIVE: The first observational study to investigate the impact of early supported discharge (ESD) on length of hospital stay in real-world conditions. DESIGN: Using historical prospective Sentinel Stroke National Audit Programme (SSNAP) data (1 January 2013-31 December 2016) and multilevel modelling, cross-sectional (2015-2016; 30 791 patients nested within 55 hospitals) and repeated cross-sectional (2013-2014 vs 2015-2016; 49 266 patients nested within 41 hospitals) analyses were undertaken. SETTING: Hospitals were sampled across a large geographical area of England covering the West and East Midlands, the East of England and the North of England. PARTICIPANTS: Stroke patients whose data were entered into the SSNAP database by hospital teams. INTERVENTIONS: Receiving ESD along the patient care pathway. PRIMARY AND SECONDARY OUTCOME MEASURES: Length of hospital stay. RESULTS: When adjusted for important case-mix variables, patients who received ESD on their stroke care pathway spent longer in hospital, compared with those who did not receive ESD. The percentage increase was 15.8% (95% CI 12.3% to 19.4%) for the 2015-2016 cross-sectional analysis and 18.8% (95% CI 13.9% to 24.0%) for the 2013-2014 versus 2015-2016 repeated cross-sectional analysis. On average, the increased length of hospital stay was approximately 1 day. CONCLUSIONS: This study has shown that by comparing ESD and non-ESD patient groups matched for important patient characteristics, receiving ESD resulted in a 1-day increase in length of hospital stay. The large reduction in length of hospital stay overall, since original trials were conducted, may explain why a reduction was not observed. The longer term benefits of accessing ESD need to be investigated further. TRIAL REGISTRATION NUMBER: http://www.isrctn.com/ISRCTN15568163.

Addition of Phenylmethylsulfonyl Fluoride Increases the Working Lifetime of the Trout Liver S9 Substrate Depletion Assay, Resulting in Improved Detection of Low Intrinsic Clearance Rates.

The activity of a trout liver S9 substrate depletion assay has been shown to decline over time, presumably due to proteolytic degradation of biotransformation enzymes. To address this problem, assay performance was evaluated following the addition of phenylmethylsulfonyl fluoride (PMSF) or a general-purpose protease inhibitor cocktail to liver homogenization buffers and/or S9 reaction mixtures. Addition of PMSF to liver homogenization buffers and/or S9 reaction mixtures had little or no effect on clearance of phenanthrene, a model cytochrome P450 substrate, in short-term (25 or 30 min) depletion experiments but resulted in significant improvements in retention of this initial activity over time. The protease inhibitor cocktail strongly inhibited initial activity when added to homogenization buffers or reaction mixtures. Taking into consideration potential effects on liver carboxylesterases, the treatment approach determined to be optimal was addition of 10 µM PMSF to the S9 reaction mixture. Addition of 10 µM PMSF to the mixture resulted in significantly higher rates of phenanthrene clearance in 2-h incubations relative to those obtained in the absence of PMSF and a 6-fold increase in the working lifetime of the preparation. The results of a statistical power analysis suggest that by increasing the working lifetime of the assay, addition of PMSF to the reaction mixture could result in substantially improved detection of low in vitro clearance rates when compared to current practice. These findings demonstrate the value of adding PMSF to the trout S9 preparation and may have broad implications for use of this assay to support chemical bioaccumulation assessments for fish. Environ Toxicol Chem 2021;40:148-161. © 2020 SETAC. This article has been contributed to by US Government employees and their work is in the public domain in the USA.

Effectiveness of Stroke Early Supported Discharge: Analysis From a National Stroke Registry.

BACKGROUND: Implementation of stroke early supported discharge (ESD) services has been recommended in many countries' clinical guidelines, based on clinical trial evidence. This is the first observational study to investigate the effectiveness of ESD service models operating in real-world conditions, at scale. METHODS AND RESULTS: Using historical prospective data from the United Kingdom Sentinel Stroke National Audit Programme (January 1, 2016-December 31, 2016), measures of ESD effectiveness were "days to ESD" (number of days from hospital discharge to first ESD contact; n=6222), "rehabilitation intensity" (total number of treatment days/total days with ESD; n=5891), and stroke survivor outcome (modified Rankin scale at ESD discharge; n=6222). ESD service models (derived from Sentinel Stroke National Audit Programme postacute organizational audit data) were categorized with a 17-item score, reflecting adoption of ESD consensus core components (evidence-based criteria). Multilevel modeling analysis was undertaken as patients were clustered within ESD teams across the Midlands, East, and North of England (n=31). A variety of ESD service models had been adopted, as reflected by variability in the ESD consensus score. Controlling for patient characteristics and Sentinel Stroke National Audit Programme hospital score, a 1-unit increase in ESD consensus score was significantly associated with a more responsive ESD service (reduced odds of patient being seen after ≥1 day of 29% [95% CI, 1%-49%] and increased treatment intensity by 2% [95% CI, 0.3%-4%]). There was no association with stroke survivor outcome measured by the modified Rankin Scale. CONCLUSIONS: This study has shown that adopting defined core components of ESD is associated with providing a more responsive and intensive ESD service. This shows that adherence to evidence-based criteria is likely to result in a more effective ESD service as defined by process measures. Registration: URL: http://www.isrctn.com/; Unique identifier: ISRCTN15568163.

Dietary Bioaccumulation and Biotransformation of Hydrophobic Organic Sunscreen Agents in Rainbow Trout.

The present study investigated the dietary bioaccumulation and biotransformation of hydrophobic organic sunscreen agents, 2-ethylhexyl-4-methoxycinnamate (EHMC) and octocrylene (OCT), in rainbow trout using a modified Organisation for Economic Co-operation and Development 305 dietary bioaccumulation test that incorporated nonbiotransformed reference chemicals. Trout were exposed to 3 dietary concentrations of each chemical to investigate the relationship between dietary exposure concentration and observed accumulation and depuration. Both EHMC and OCT were significantly biotransformed, resulting in mean in vivo whole-body biotransformation rate constants (kMET ) of 0.54 ± 0.06 and 0.09 ± 0.01 d-1 , respectively. The kMET values generated for both chemicals did not differ between dietary exposure concentrations, indicating that chemical concentrations in the fish were not high enough to saturate biotransformation enzymes. Both somatic and luminal biotransformation substantially reduce EHMC and OCT bioaccumulation potential in trout. Biomagnification factors (BMFs) and bioconcentration factors (BCFs) of EHMC averaged 0.0035 kg lipid kg lipid-1 and 396 L kg-1 , respectively, whereas those of OCT averaged 0.0084 kg lipid kg lipid-1 and 1267 L kg-1 . These values are 1 to 2 orders of magnitude lower than the BMFs and BCFs generated for reference chemicals of similar log KOW . In addition, for both chemicals, derived BMFs and BCFs fell below established bioaccumulation criteria (1.0 kg lipid kg lipid-1 and 2000 L kg-1 , respectively), suggesting that EHMC ad OCT are unlikely to bioaccumulate to a high degree in aquatic biota. Environ Toxicol Chem 2020;39:574-586. © 2019 SETAC.

Biotransformation of Polycyclic Aromatic Hydrocarbons by Trout Liver S9 Fractions: Evaluation of Competitive Inhibition Using a Substrate Depletion Approach.

Environmental contaminants frequently occur as part of a chemical mixture, potentially resulting in competitive inhibition among multiple substrates metabolized by the same enzyme. Trout liver S9 fractions were used to evaluate the biotransformation of 3 polycyclic aromatic hydrocarbons (PAHs): phenanthrene, pyrene, and benzo[a]pyrene, tested as binary mixtures. Initial rates of biotransformation were determined using a substrate-depletion approach. The resulting data were then fitted by simultaneous nonlinear regression to a competitive inhibition model. In each case, the PAH possessing the lower Michaelis-Menten affinity constant (KM ) competitively inhibited biotransformation of the other compound. Inhibition constants determined for the lower-KM compound were generally close to previously determined KM values, consistent with the suggestion that phase I biotransformation of PAHs is largely catalyzed by one or a small number of cytochrome P450 enzymes. The use of a substrate-depletion approach to perform enzyme-inhibition studies imposes practical limitations on experimental design and complicates the interpretation of derived kinetic constants. Nevertheless, the resulting information may have utility for chemical hazard assessments as well as the design and interpretation of controlled laboratory studies. Depletion experiments informed by measured chemical concentrations in tissues may also provide a means of determining whether enzyme inhibition occurs under relevant environmental conditions. Environ Toxicol Chem 2019;38:2729-2739. Published 2019 Wiley Periodicals, Inc. on behalf of SETAC. This article is a US government work, and as such, is in the public domain in the United States of America.

What is the impact of large-scale implementation of stroke Early Supported Discharge? A mixed methods realist evaluation study protocol.

BACKGROUND: Stroke Early Supported Discharge (ESD) is a service innovation that facilitates discharge from hospital and delivery of specialist rehabilitation in patients' homes. There is currently widespread implementation of ESD services in many countries, driven by robust clinical trial evidence. In England, the type of ESD service patients receive on the ground is variable, and in some regions, ESD is still not offered at all. This protocol presents a study designed to investigate the mechanisms and outcomes of implementing ESD at scale in real-world conditions. This will help to establish which models of ESD are most effective and in what context. METHODS: A realist evaluation approach composed of two interlinking work packages will be adopted to investigate how and why ESD works, for whom and in what circumstances. Work package 1 (WP1) will begin with a rapid evidence synthesis to formulate preliminary realist hypotheses. Quantitative analyses of historical prospective Sentinel Stroke National Audit Programme (SSNAP) data will be performed to evaluate service outcomes based on the degree to which evidence-based ESD has been implemented. Work package 2 (WP2) will involve the qualitative investigation of purposively selected case study sites featuring in WP1 and covering different regions in England. The perspectives of clinicians, managers, commissioners, and service users will be explored qualitatively. Cost implications of ESD models will be examined using a cost-consequence analysis. Cross-case comparisons and triangulation of the data sources from both work packages will be performed to test, revise, and refine initial programme theories and address research aims. DISCUSSION: This study will investigate whether and how current large-scale implementation of ESD is achieving the outcomes suggested by the evidence base. The theory-driven evaluation approach will highlight key mechanisms and contextual conditions necessary to optimise outcomes and allow us to draw transferable lessons to inform the effective implementation and sustainability of ESD in clinical practice. In addition, the methodological framework will progress the theoretical understanding of implementation and evaluation of complex rehabilitation interventions in stroke care. TRIAL REGISTRATION: ISRCTN: 15568163, registration date: 26 October 2018.

Physiotherapy provision to hospitalised stroke patients: Analysis from the UK Sentinel Stroke National Audit Programme.

INTRODUCTION: The purpose of this study is to investigate which factors are associated with physiotherapy provision to hospitalised stroke patients. METHODS: Data were analysed for stroke patients admitted to hospital in England and Wales between April 2013 and March 2017 recorded on the Sentinel Stroke National Audit Programme (SSNAP) national stroke register. Associations between different patient factors, and applicability for and intensity of physiotherapy were measured using multi-level logistic and regression models.Findings: Data from 306,078 patients were included on the SSNAP register. Median age was 77 years (IQR 67-85) and 84.7% of patients with completed stroke severity data had a mild-moderate stroke. In all, 85.2% of patients recorded on SSNAP were deemed applicable for physiotherapy. Applicability for physiotherapy was 47% higher among thrombolysed patients (aOR 1.47, 95% CI 1.40-1.54), 36% lower in those with severe pre-morbid disability (aOR 0.64, 95% CI 0.58-0.71) and more than 2.5-fold higher among patients admitted to hospitals with greater availability of early supported discharge (aOR 2.62, 95% CI 1.28-5.37). Patients who were younger, male, had less pre-morbid disability, lower stroke severity, sustained an infarction, received thrombolysis, and had fewer medical complications were more likely to receive more intensive physiotherapy post-stroke. CONCLUSION: Several patient and service organisational factors are associated with physiotherapy provision to stroke patients, some of which may not be justifiable. Physiotherapists should be aware of these factors when planning and delivering physiotherapy as well as any possible biases associated with physiotherapy provision to patients post-stroke.

Associations Between 30-Day Mortality, Specialist Nursing, and Daily Physician Ward Rounds in a National Stroke Registry.

Background and Purpose- Well-organized stroke care is associated with better patient outcomes, but the most important organizational factors are unknown. Methods- Data were extracted from the Sentinel Stroke National Audit Programme of adults with acute stroke treated in stroke hospitals in England and Wales between April 2013 and March 2015. Multilevel models with random intercepts for hospitals were used to estimate the association of each variable with 30-day mortality to estimate the impact of admission to differently organized hospitals. Results- Of the 143 578 patients with acute stroke admitted to 154 hospitals, 14.4% died within 30 days of admission. In adjusted analyses, admission to hospitals with higher ratios of nurses trained in swallow screening was associated with reduced odds of death ( P=0.004), and admission to hospitals with daily physician ward rounds was associated with 10% lower odds of mortality compared with less-frequent ward rounds (95% CI, 0.82-0.98; P=0.013). Number of stroke admissions and overall ratio of registered nurses on duty at weekends were not found to be independently associated with mortality after adjustment for other factors. Conclusions- If these associations are causal, an extra 1332 deaths annually in England and Wales could be saved by hospitals providing care associated with a ratio of nurses trained in swallow screening of at least 3 per 10 beds and daily stroke physician ward rounds.

Allometric scaling of hepatic biotransformation in rainbow trout.

Biotransformation may substantially impact the toxicity and accumulation of xenobiotic chemicals in fish. However, this activity can vary substantially within and among species. In this study, liver S9 fractions from rainbow trout (4-400 g) were used to evaluate relationships between fish body mass and the activities of phase I and phase II metabolic enzymes. An analysis of log-transformed data, expressed per gram of liver (g liver-1), showed that total cytochrome P450 (CYP) concentration, UDP-glucuronosyltransferase (UGT) activity, and glutathione S-transferase (GST) activity exhibited small but significant inverse relationships with fish body weight. In contrast, in vitro intrinsic clearance rates (CLIN VITRO,INT) for three polycyclic aromatic hydrocarbons (PAHs) increased with increasing body weight. Weight normalized liver mass also decreased inversely with body weight, suggesting a need to express hepatic metabolism data per gram of body weight (g BW-1) in order to reflect the metabolic capabilities of the whole animal. When the data were recalculated in this manner, negative allometric relationships for CYP concentration, UGT activity, and GST activity became more pronounced, while CLIN VITRO,INT rates for the three PAHs showed no significant differences across fish sizes. Ethoxyresorufin O-deethylase (EROD) activity normalized to tissue weight (g liver-1) or body weight (g BW-1) exhibited a non-monotonic pattern with respect to body weight. The results of this study may have important implications for chemical modeling efforts with fish.

The economic burden of stroke care in England, Wales and Northern Ireland: Using a national stroke register to estimate and report patient-level health economic outcomes in stroke.

INTRODUCTION: Stroke registries are used in many settings to measure stroke treatment and outcomes, but rarely include data on health economic outcomes. We aimed to extend the Sentinel Stroke National Audit Programme registry of England, Wales and Northern Ireland to derive and report patient-level estimates of the cost of stroke care. METHODS: An individual patient simulation model was built to estimate health and social care costs at one and five years after stroke, and the cost-benefits of thrombolysis and early supported discharge. Costs were stratified according to age, sex, stroke type (ischaemic or primary intracerebral haemorrhage) and stroke severity. The results were illustrated using data on all patients with stroke included in Sentinel Stroke National Audit Programme from April 2015 to March 2016 (n = 84,184). RESULTS: The total cost of health and social care for patients with acute stroke each year in England, Wales and Northern Ireland was £3.60 billion in the first five years after admission (mean per patient cost: £46,039). There was fivefold variation in the magnitude of costs between patients, ranging from £19,101 to £107,336. Costs increased with older age, increasing stroke severity and intracerebral hemorrhage stroke. Increasing the proportion of eligible patients receiving thrombolysis or early supported discharge was estimated to save health and social care costs by five years after stroke. DISCUSSION: The cost of stroke care is large and varies widely between patients. Increasing the proportion of eligible patients receiving thrombolysis or early supported discharge could contribute to reducing the financial burden of stroke. CONCLUSION: Extending stroke registers to report individualised data on costs may enhance their potential to support quality improvement and research.

20 years of researching stroke through audit.

Over the last 20 years, England, Wales and Northern Ireland have developed an audit programme that now encompasses nearly all patients admitted to hospital with a stroke. This article records and reviews some questions that have been answered using data from the audit: Is the rate of institutional care after rehabilitation a possible measure of outcome? Does stroke unit care in routine practice give the benefits shown in randomized controlled trials? How is the quality of stroke care affected by a patient's age and the time of their stroke? Do patient-reported measures match those obtained from the professionals recording of processes of care? How do the processes of care after stroke affect mortality? Is thrombolysis safe to use in patients over the age of 80? Do staffing levels matter? Does assessing the safety of swallowing really make a difference? Do clinicians make rational decisions about end-of-life care in patients with haemorrhage? Does socioeconomic status influence the risk of stroke, outcome after stroke and the quality of stroke care? How much does stroke really cost in England, Wales and Northern Ireland? The article concludes that this national audit has improved stroke care across the United Kingdom, has given answers to important questions that could not be answered in any other way and has shown that benefits found in research do generalize into real clinical benefits in day-to-day practice.

Why do stroke survivors not receive recommended amounts of active therapy? Findings from the ReAcT study, a mixed-methods case-study evaluation in eight stroke units.

OBJECTIVE: To identify why the National Clinical Guideline recommendation of 45 minutes of each appropriate therapy daily is not met in many English stroke units. DESIGN: Mixed-methods case-study evaluation, including modified process mapping, non-participant observations of service organisation and therapy delivery, documentary analysis and semi-structured interviews. SETTING: Eight stroke units in four English regions. SUBJECTS: Seventy-seven patients with stroke, 53 carers and 197 stroke unit staff were observed; 49 patients, 50 carers and 131 staff participants were interviewed. RESULTS: Over 1000 hours of non-participant observations and 433 patient-specific therapy observations were undertaken. The most significant factor influencing amount and frequency of therapy provided was the time therapists routinely spent, individually and collectively, in information exchange. Patient factors, including fatigue and tolerance influenced therapists' decisions about frequency and intensity, typically resulting in adaptation of therapy rather than no provision. Limited use of individual patient therapy timetables was evident. Therapist staffing levels were associated with differences in therapy provision but were not the main determinant of intensity and frequency. Few therapists demonstrated understanding of the evidence underpinning recommendations for increased therapy frequency and intensity. Units delivering more therapy had undertaken patient-focused reorganisation of therapists' working practices, enabling them to provide therapy consistent with guideline recommendations. CONCLUSION: Time spent in information exchange impacted on therapy provision in stroke units. Reorganisation of therapists' work improved alignment with guidelines.

Socioeconomic disparities in first stroke incidence, quality of care, and survival: a nationwide registry-based cohort study of 44 million adults in England.

BACKGROUND: We aimed to estimate socioeconomic disparities in the incidence of hospitalisation for first-ever stroke, quality of care, and post-stroke survival for the adult population of England. METHODS: In this cohort study, we obtained data collected by a nationwide register on patients aged 18 years or older hospitalised for first-ever acute ischaemic stroke or primary intracerebral haemorrhage in England from July 1, 2013, to March 31, 2016. We classified socioeconomic status at the level of Lower Super Output Areas using the Index of Multiple Deprivation, a neighbourhood measure of deprivation. Multivariable models were fitted to estimate the incidence of hospitalisation for first stroke (negative binomial), quality of care using 12 quality metrics (multilevel logistic), and all-cause 1 year case fatality (Cox proportional hazards). FINDINGS: Of the 43·8 million adults in England, 145 324 were admitted to hospital with their first-ever stroke: 126 640 (87%) with ischaemic stroke, 17 233 (12%) with intracerebral haemorrhage, and 1451 (1%) with undetermined stroke type. We observed a socioeconomic gradient in the incidence of hospitalisation for ischaemic stroke (adjusted incidence rate ratio 2·0, 95% CI 1·7-2·3 for the most vs least deprived deciles) and intracerebral haemorrhage (1·6, 1·3-1·9). Patients from the lowest socioeconomic groups had first stroke a median of 7 years earlier than those from the highest (p<0·0001), and had a higher prevalence of pre-stroke disability and diabetes. Patients from lower socioeconomic groups were less likely to receive five of 12 care processes but were more likely to receive early supported discharge (adjusted odds ratio 1·14, 95% CI 1·07-1·22). Low socioeconomic status was associated with a 26% higher adjusted risk of 1-year mortality (adjusted hazard ratio 1·26, 95% CI 1·20-1·33, for highest vs lowest deprivation decile), but this gradient was largely attenuated after adjustment for the presence of pre-stroke diabetes, hypertension, and atrial fibrillation (1·11, 1·05-1·17). INTERPRETATION: Wide socioeconomic disparities exist in the burden of ischaemic stroke and intracerebral haemorrhage in England, most notably in stroke hospitalisation risk and case fatality and, to a lesser extent, in the quality of health care. Reducing these disparities requires interventions to improve the quality of acute stroke care and address disparities in cardiovascular risk factors present before stroke. FUNDING: NHS England and the Welsh Government.

Toxicokinetics of the neonicotinoid insecticide imidacloprid in rainbow trout (Oncorhynchus mykiss).

Studies were conducted to determine the distribution and elimination of imidacloprid (IMI) in rainbow trout. Animals were injected with a low (47.6 µg/kg), medium (117.5 µg/kg) or high (232.7 µg/kg) dose directly into the bloodstream and allowed to depurate. The fish were then sampled to characterize the loss of IMI from plasma and its appearance in expired water (all dose groups) and urine (medium dose only). In vitro biotransformation of IMI was evaluated using trout liver S9 fractions. Mean total clearance (CLT) values determined by non-compartmental analysis of plasma time-course data were 21.8, 27.0 and 19.5 mL/h/kg for the low, medium and high dose groups, respectively. Estimated half-lives for the same groups were 67.0, 68.4 and 68.1 h, while fitted values for the steady-state volume of distribution (VSS) were 1.72, 2.23 and 1.81 L/kg. Branchial elimination rates were much lower than expected, suggesting that IMI is highly bound in blood. Renal clearance rates were greater than measured rates of branchial clearance (60% of CLT in the medium dose group), possibly indicating a role for renal membrane transporters. There was no evidence for hepatic biotransformation of IMI. Collectively, these findings suggest that IMI would accumulate in trout in continuous waterborne exposures.

Comparison of trout hepatocytes and liver S9 fractions as in vitro models for predicting hepatic clearance in fish.

Isolated hepatocytes and liver S9 fractions have been used to collect in vitro biotransformation data for fish as a means of improving modeled estimates of chemical bioaccumulation. To date, however, there have been few direct comparisons of these 2 methods. In the present study, cryopreserved trout hepatocytes were used to measure in vitro intrinsic clearance rates for 6 polycyclic aromatic hydrocarbons (PAHs). These rates were extrapolated to estimates of in vivo intrinsic clearance and used as inputs to a well stirred liver model to predict hepatic clearance. Predicted rates of hepatic clearance were then evaluated by comparison with measured rates determined previously using isolated perfused livers. Hepatic clearance rates predicted using hepatocytes were in good agreement with measured values (<2.1-fold difference for 5 of 6 compounds) under 2 competing binding assumptions. These findings, which may be attributed in part to high rates of PAH metabolism, are similar to those obtained previously using data from liver S9 fractions. For 1 compound (benzo[a]pyrene), the in vivo intrinsic clearance rate calculated using S9 data was 10-fold higher than that determined using hepatocytes, possibly due to a diffusion limitation on cellular uptake. Generally, however, there was good agreement between calculated in vivo intrinsic clearance rates obtained using either in vitro test system. These results suggest that both systems can be used to improve bioaccumulation assessments for fish, particularly when vitro rates of activity are relatively high, although additional work is needed to determine if the chemical domain of applicability for each system differs. Environ Toxicol Chem 2017;36:463-471. Published 2016 SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.

Care-limiting decisions in acute stroke and association with survival: analyses of UK national quality register data.

BACKGROUND: Prognosis after intracerebral hemorrhage (ICH) is poor and care-limiting decisions may worsen outcomes. AIMS: To determine whether in current UK stroke practice, key acute care decisions are associated with stroke subtype (ICH/ischemic) and whether these decisions are independently associated with survival. METHODS: We extracted data describing all stroke patients included in a UK quality register between 1 April 2013 and 31 March 2014. Key care decisions in our analyses were transfer to higher level care on admission and palliation in the first 72 h. We used multivariable regression models to test for associations between stroke subtype (ICH/ischemic), key care decisions, and survival. RESULTS: A total of 65,818 patients were included in the final analysis. After ICH (n = 7020/65,818, 10.7%), 10.5% were palliated on the day of admission and 19.3% by 72 h (vs. 0.7% and 3.3% for ischemic stroke). Although a greater proportion were admitted directly to higher level care after ICH (3.7% vs. 1.5% for ischemic stroke), ICH was not independently associated with the decision to admit to higher level care (adjusted odds ratio (OR): 1.12, 95% confidence interval (95%CI): 0.95-1.31, p = 0.183). However, ICH was strongly associated with the decision to commence palliative care on the day of admission (OR: 7.27, 95%CI: 6.31-8.37, p < 0.001). Palliative care was independently associated with risk of death by 30 days regardless of stroke subtype. CONCLUSIONS: When compared to ischemic stroke, patients with ICH are much more likely to commence palliative care during the first 72 h of their care, independent of level of consciousness, age, and premorbid health.

Toxicokinetics of perfluorooctane sulfonate in rainbow trout (Oncorhynchus mykiss).

Rainbow trout (Oncorhynchus mykiss) confined to respirometer-metabolism chambers were dosed with perfluorooctane sulfonate (PFOS) by intra-arterial injection and sampled to obtain concentration time-course data for plasma and either urine or expired water. The data were then analyzed using a 2-compartment clearance-volume model. Renal and branchial clearance rates (mL/d/kg) determined for all experiments averaged 19% and 81% of total clearance, respectively. Expressed as mean values for all experiments, the steady-state volume of distribution was 277 mL/kg and the terminal half-life was 86.8 d. Additional animals were exposed to PFOS in water, resulting in an average calculated branchial uptake efficiency of 0.36%. The renal clearance rate determined in the present study is approximately 75 times lower than that determined in earlier studies with perfluorooctanoate (PFOA). Previously, it was suggested that PFOA is a substrate for membrane transporters in the trout kidney. The present study suggests that glomerular filtration may be sufficient to explain the observed renal clearance rate for PFOS, although a role for membrane transporters cannot be ruled out. These findings demonstrate that models developed to predict the bioaccumulation of perfluoroalkyl acids by fish must account for differences in renal clearance of individual compounds.

Effects of Centralizing Acute Stroke Services on Stroke Care Provision in Two Large Metropolitan Areas in England.

BACKGROUND AND PURPOSE: In 2010, Greater Manchester and London centralized acute stroke care into hyperacute units (Greater Manchester=3, London=8), with additional units providing ongoing specialist stroke care nearer patients' homes. Greater Manchester patients presenting within 4 hours of symptom onset were eligible for hyperacute unit admission; all London patients were eligible. Research indicates that postcentralization, only London's stroke mortality fell significantly more than elsewhere in England. This article attempts to explain this difference by analyzing how centralization affects provision of evidence-based clinical interventions. METHODS: Controlled before and after analysis was conducted, using national audit data covering Greater Manchester, London, and a noncentralized urban comparator (38 623 adult stroke patients, April 2008 to December 2012). Likelihood of receiving all interventions measured reliably in pre- and postcentralization audits (brain scan; stroke unit admission; receiving antiplatelet; physiotherapist, nutrition, and swallow assessments) was calculated, adjusting for age, sex, stroke-type, consciousness, and whether stroke occurred in-hospital. RESULTS: Postcentralization, likelihood of receiving interventions increased in all areas. London patients were overall significantly more likely to receive interventions, for example, brain scan within 3 hours: Greater Manchester=65.2% (95% confidence interval=64.3-66.2); London=72.1% (71.4-72.8); comparator=55.5% (54.8-56.3). Hyperacute units were significantly more likely to provide interventions, but fewer Greater Manchester patients were admitted to these (Greater Manchester=39%; London=93%). Differences resulted from contrasting hyperacute unit referral criteria and how reliably they were followed. CONCLUSIONS: Centralized systems admitting all stroke patients to hyperacute units, as in London, are significantly more likely to provide evidence-based clinical interventions. This may help explain previous research showing better outcomes associated with fully centralized models.

Observed and modeled effects of pH on bioconcentration of diphenhydramine, a weakly basic pharmaceutical, in fathead minnows.

A need exists to better understand the influence of pH on the uptake and accumulation of ionizable pharmaceuticals in fish. In the present study, fathead minnows were exposed to diphenhydramine (DPH; disassociation constant = 9.1) in water for up to 96 h at 3 nominal pH levels: 6.7, 7.7, and 8.7. In each case, an apparent steady state was reached by 24 h, allowing for direct determination of the bioconcentration factor (BCF), blood-water partitioning (PBW,TOT), and apparent volume of distribution (approximated from the whole-body-plasma concentration ratio). The BCFs and measured PBW,TOT values increased in a nonlinear manner with pH, whereas the volume of distribution remained constant, averaging 3.0 L/kg. The data were then simulated using a model that accounts for acidification of the gill surface caused by elimination of metabolically produced acid. Good agreement between model simulations and measured data was obtained for all tests by assuming that plasma binding of ionized DPH is 16% that of the neutral form. A simpler model, which ignores elimination of metabolically produced acid, performed less well. These findings suggest that pH effects on accumulation of ionizable compounds in fish are best described using a model that accounts for acidification of the gill surface. Moreover, measured plasma binding and volume of distribution data for humans, determined during drug development, may have considerable value for predicting chemical binding behavior in fish.