High-Throughput Screening to Advance In Vitro Toxicology: Accomplishments, Challenges, and Future Directions

Traditionally, chemical toxicity is determined by in vivo animal studies, which are low throughput, expensive, and sometimes fail to predict compound toxicity in humans. Due to the increasing number of chemicals in use and the high rate of drug candidate failure due to toxicity, it is imperative to develop in vitro, high-throughput screening methods to determine toxicity. The Tox21 program, a unique research consortium of federal public health agencies, was established to address and identify toxicity concerns in a high-throughput, concentration-responsive manner using a battery of in vitro assays. In this article, we review the advancements in high-throughput robotic screening methodology and informatics processes to enable the generation of toxicological data, and their impact on the field; further, we discuss the future of assessing environmental toxicity utilizing efficient and scalable methods that better represent the corresponding biological and toxicodynamic processes in humans.

Reassessment of the cadmium toxicological reference value for use in human health assessments of foods

The U.S. Food and Drug Administration (FDA) developed an oral toxicological reference value (TRV) for characterizing potential health concerns from dietary exposure to cadmium (Cd). The development of the TRV leveraged the FDA's previously published research including (1) a systematic review for adverse health effects associated with oral Cd exposure and (2) a human physiological based pharmacokinetic (PBPK) model adapted from Kjellstrom and Nordberg (1978) for use in reverse dosimetry applied to the U.S. population. Adverse effects of Cd on the bone and kidney are associated with similar points of departure (PODs) of approximately 0.50 μg Cd/g creatinine for females aged 50-60 based on available epidemiologic data. We also used the upper bound estimate of the renal cortical concentration (50 μg/g Cd) occurring in the U.S. population at 50 years of age as a POD. Based on the output from our reverse dosimetry PBPK Model, a range of 0.21-0.36 μg/kg bw/day was developed for the TRV. The animal data used for the animal TRV derivation (0.63-1.8 μg/kg bw/day) confirms biological plausibility for both the bone and kidney endpoints.

Self-report and urine drug screen concordance among women with co-occurring PTSD and substance use disorders participating in a clinical trial: Impact of drug type and participant characteristics

BACKGROUND

Self-report measures are important in substance use assessment, yet they are susceptible to reporting errors. Urine drug screens (UDS) are often considered a more valid alternative. However, collecting in-person UDS may not always be feasible, contributing to the need to understand factors that influence the validity of self-reported substance use.

METHODS

In this secondary analysis of data from 295 women with co-occurring PTSD and substance use disorders (SUD) who participated in a clinical trial testing behavioral interventions, we examined concordance and discordance between self-reported drug use and associated UDS results. Generalized linear mixed models were used to examine the impact of treatment type and participant characteristics on the associations between self-reported drug use and UDS results.

RESULTS

Findings revealed higher disagreement between self-report and UDS for opioids and sedatives (ranging from.77 to.90) and lower disagreement rates for cannabis and cocaine (ranging from.26 to.33). Treatment type was not a significant moderator of the associations between self-report and UDS across all drugs. Among those with a positive opioid UDS, those who reported employment in the past three years were more likely to self-report no opioid use compared to their counterparts without employment in the past three years.

CONCLUSIONS

Findings add to the literature that supports the validity of self-reported cannabis and cocaine use. The greater discrepancies between self-report and UDS test results of opioids and sedatives suggest adjunctive UDS may be required, although a variety of factors other than inaccurate self-report may be associated with this discrepancy.

PROTOCOL: An evidence and gap map of studies of implementation issues for interventions for those affected by and at risk of homelessness in high-income countries

This is the protocol for a Campbell systematic review. The objectives are as follows. The proposed evidence and gap map will present relevant process evaluations and other studies of barriers and facilitators, both qualitative and quantitative, for eligible homelessness interventions to highlight the issues arising in the implementation of these interventions. Specifically, the objectives of the map are to: (i) develop a clear taxonomy of interventions and implementation issues (e.g., barriers and facilitators-factors which works as barriers to hinder successful implementation of policies and programmes and factors which facilitate the intervention and therefore support its implementation) related to homelessness in high-income countries; (ii) map available systematic reviews and primary studies of the implementation issues of interventions for those experiencing homelessness and those at risk of homelessness, with an overview provided in a summary report; (iii) provide a searchable database of included studies accessible to research users via CHI website.

Feasibility and Acceptability of a Novel Online Program for Mental Health Carers

Objective

To evaluate the feasibility and acceptability of a new online program (Minds Together ) for carers of a person with depressive or anxiety symptoms.

Methods

Using a two-arm randomised controlled trial design, 108 carers of a person with depressive or anxiety symptomology aged 16 years or over (89% female; mean age 50 years) received immediate or delayed access to the Minds Together program. Feasibility was measured using program activation and survey completion rates. Acceptability was measured using a project-specific satisfaction scale, semi-structured interviews, and program completion metadata. The study used intention-to-treat (ITT) analysis for participant-reported outcomes (carer burden, coping self-efficacy) across groups.

Results

Feasibility and acceptability thresholds were consistent with similar studies: 59% activated their program account, 47% met the program completion threshold, and almost all reported satisfaction with the program. The ITT indicated trends in increased coping self-efficacy and reduced carer burden for the Intervention group, compared to the Waitlist control.

Conclusions

The Minds Together program is a feasible and acceptable program for carers supporting a person with depressive or anxiety symptomology. Results support exploration of the program's efficacy in a full-scale RCT.

Machine learning models for rat multigeneration reproductive toxicity prediction

Reproductive toxicity is one of the prominent endpoints in the risk assessment of environmental and industrial chemicals. Due to the complexity of the reproductive system, traditional reproductive toxicity testing in animals, especially guideline multigeneration reproductive toxicity studies, take a long time and are expensive. Therefore, machine learning, as a promising alternative approach, should be considered when evaluating the reproductive toxicity of chemicals. We curated rat multigeneration reproductive toxicity testing data of 275 chemicals from ToxRefDB (Toxicity Reference Database) and developed predictive models using seven machine learning algorithms (decision tree, decision forest, random forest, k-nearest neighbors, support vector machine, linear discriminant analysis, and logistic regression). A consensus model was built based on the seven individual models. An external validation set was curated from the COSMOS database and the literature. The performances of individual and consensus models were evaluated using 500 iterations of 5-fold cross-validations and the external validation data set. The balanced accuracy of the models ranged from 58% to 65% in the 5-fold cross-validations and 45%–61% in the external validations. Prediction confidence analysis was conducted to provide additional information for more appropriate applications of the developed models. The impact of our findings is in increasing confidence in machine learning models. We demonstrate the importance of using consensus models for harnessing the benefits of multiple machine learning models (i.e., using redundant systems to check validity of outcomes). While we continue to build upon the models to better characterize weak toxicants, there is current utility in saving resources by being able to screen out strong reproductive toxicants before investing in vivo testing. The modeling approach (machine learning models) is offered for assessing the rat multigeneration reproductive toxicity of chemicals. Our results suggest that machine learning may be a promising alternative approach to evaluate the potential reproductive toxicity of chemicals.

Emerging technologies and their impact on regulatory science

There is an evolution and increasing need for the utilization of emerging cellular, molecular and in silico technologies and novel approaches for safety assessment of food, drugs, and personal care products. Convergence of these emerging technologies is also enabling rapid advances and approaches that may impact regulatory decisions and approvals. Although the development of emerging technologies may allow rapid advances in regulatory decision making, there is concern that these new technologies have not been thoroughly evaluated to determine if they are ready for regulatory application, singularly or in combinations. The magnitude of these combined technical advances may outpace the ability to assess fit for purpose and to allow routine application of these new methods for regulatory purposes. There is a need to develop strategies to evaluate the new technologies to determine which ones are ready for regulatory use. The opportunity to apply these potentially faster, more accurate, and cost-effective approaches remains an important goal to facilitate their incorporation into regulatory use. However, without a clear strategy to evaluate emerging technologies rapidly and appropriately, the value of these efforts may go unrecognized or may take longer. It is important for the regulatory science field to keep up with the research in these technically advanced areas and to understand the science behind these new approaches. The regulatory field must understand the critical quality attributes of these novel approaches and learn from each other's experience so that workforces can be trained to prepare for emerging global regulatory challenges. Moreover, it is essential that the regulatory community must work with the technology developers to harness collective capabilities towards developing a strategy for evaluation of these new and novel assessment tools.

Neurobehavioral and neurochemical effects of perinatal arsenite exposure in Sprague-Dawley rats

Exposure to relatively high levels of inorganic arsenic (iAs) is associated with detrimental effects on human health, including cancer and diabetes. The effects of lower-level exposures are less clear, and gaps in the literature exist as to the effects of iAs exposure on neurodevelopment. The current study assessed the effects of perinatal iAs exposure on rodent neurodevelopment and behavior. Pregnant Sprague-Dawley (SD) rats were exposed to arsenite (AsIII) via oral gavage on gestational days (GD) 6 through 21, and pups were directly dosed via gavage on postnatal days (PND) 1 through 21. Dams and offspring received the same doses: 0.00, 0.10, 1.50, or 3.75 mg/kg/day. Male and female offspring underwent a battery of behavioral assessments from weaning until PND 180. Brain arsenic levels increased in a dose-dependent manner at both PND 1 and 21. Results from the behavioral tests show that pre- and postnatal AsIII exposure did not adversely affect offspring weight gain, adolescent motor and cognitive functions, or adult motor and cognitive functions in the SD rat. There were no differences in concentration of several brain proteins associated with blood-brain barrier permeability, dopamine functions, and inflammation.

3D cell culture models: Drug pharmacokinetics, safety assessment, and regulatory consideration

Nonclinical testing has served as a foundation for evaluating potential risks and effectiveness of investigational new drugs in humans. However, the current two-dimensional (2D) in vitro cell culture systems cannot accurately depict and simulate the rich environment and complex processes observed in vivo, whereas animal studies present significant drawbacks with inherited species-specific differences and low throughput for increased demands. To improve the nonclinical prediction of drug safety and efficacy, researchers continue to develop novel models to evaluate and promote the use of improved cell- and organ-based assays for more accurate representation of human susceptibility to drug response. Among others, the three-dimensional (3D) cell culture models present physiologically relevant cellular microenvironment and offer great promise for assessing drug disposition and pharmacokinetics (PKs) that influence drug safety and efficacy from an early stage of drug development. Currently, there are numerous different types of 3D culture systems, from simple spheroids to more complicated organoids and organs-on-chips, and from single-cell type static 3D models to cell co-culture 3D models equipped with microfluidic flow control as well as hybrid 3D systems that combine 2D culture with biomedical microelectromechanical systems. This article reviews the current application and challenges of 3D culture systems in drug PKs, safety, and efficacy assessment, and provides a focused discussion and regulatory perspectives on the liver-, intestine-, kidney-, and neuron-based 3D cellular models.

Paving the way for application of next generation risk assessment to safety decision-making for cosmetic ingredients

Next generation risk assessment (NGRA) is an exposure-led, hypothesis-driven approach that has the potential to support animal-free safety decision-making. However, significant effort is needed to develop and test the in vitro and in silico (computational) approaches that underpin NGRA to enable confident application in a regulatory context. A workshop was held in Montreal in 2019 to discuss where effort needs to be focussed and to agree on the steps needed to ensure safety decisions made on cosmetic ingredients are robust and protective. Workshop participants explored whether NGRA for cosmetic ingredients can be protective of human health, and reviewed examples of NGRA for cosmetic ingredients. From the limited examples available, it is clear that NGRA is still in its infancy, and further case studies are needed to determine whether safety decisions are sufficiently protective and not overly conservative. Seven areas were identified to help progress application of NGRA, including further investments in case studies that elaborate on scenarios frequently encountered by industry and regulators, including those where a ‘high risk’ conclusion would be expected. These will provide confidence that the tools and approaches can reliably discern differing levels of risk. Furthermore, frameworks to guide performance and reporting should be developed.

Accommodation-based interventions for individuals experiencing, or at risk of experiencing, homelessness

Background

Globally, almost 1.6 billion individuals lack adequate housing. Many accommodation-based approaches have evolved across the globe to incorporate additional support and services beyond delivery of housing.

Objectives

This review examines the effectiveness of accommodation-based approaches on outcomes including housing stability, health, employment, crime, wellbeing, and cost for individuals experiencing or at risk of experiencing homelessness.

Search Methods

The systematic review is based on evidence already identified in two existing EGMs commissioned by the Centre for Homelessness Impact (CHI) and built by White et al. The maps were constructed using a comprehensive three stage search and mapping process. Stage one mapped included studies in an existing systematic review on homelessness, stage two was an extensive search of 17 academic databases, three EGM databases, and eight systematic review databases. Finally stage three included web searches for grey literature, scanning reference lists of included studies and consultation with experts to identify additional literature. We identified 223 unique studies across 551 articles from the effectiveness map on 12th April 2019.

Selection Criteria

We include research on all individuals currently experiencing, or at risk of experiencing homelessness irrespective of age or gender, in high-income countries. The Network Meta-Analysis (NMA) contains all study designs where a comparison group was used. This includes randomised controlled trials (RCTs), quasi-experimental designs, matched comparisons and other study designs that attempt to isolate the impact of the intervention on homelessness. The NMA primarily addresses how interventions can reduce homelessness and increase housing stability for those individuals experiencing, or at risk of experiencing, homelessness. Additional outcomes are examined and narratively described. These include: access to mainstream healthcare; crime and justice; employment and income; capabilities and wellbeing; and cost of intervention. These outcomes reflect the domains used in the EGM, with the addition of cost.

Data Collection and Analysis

Due to the diverse nature of the literature on accommodation-based approaches, the way in which the approaches are implemented in practice, and the disordered descriptions of the categories, the review team created a novel typology to allow meaningful categorisations for functional and useful comparison between the various intervention types. Once these eligible categories were identified, we undertook dual data extraction, where two authors completed data extraction and risk of bias (ROB) assessments independently for each study. NMA was conducted across outcomes related to housing stability and health.Qualitative data from process evaluations is included using a "Best Fit" Framework synthesis. The purpose of this synthesis is to complement the quantitative evidence and provide a better understanding of what factors influenced programme effectiveness. All included Qualitative data followed the initial framework provided by the five main analytical categories of factors of influence (reflected in the EGM), namely: contextual factors, policy makers/funders, programme administrators/managers/implementing agencies, staff/case workers and recipients of the programme.

Main Results

There was a total of 13,128 people included in the review, across 51 reports of 28 studies. Most of the included studies were carried out in the United States of America (25/28), with other locations including Canada and the UK. Sixteen studies were RCTs (57%) and 12 were nonrandomised (quasi-experimental) designs (43%). Assessment of methodological quality and potential for bias was conducted using the second version of the Cochrane Risk of Bias tool for Randomised controlled trials. Nonrandomised studies were coded using the ROBINS- I tool. Out of the 28 studies, three had sufficiently low ROB (11%), 11 (39%) had moderate ROB, and five (18%) presented serious problems with ROB, and nine (32%) demonstrated high, critical problems with their methodology. A NMA on housing stability outcomes demonstrates that interventions offering the highest levels of support alongside unconditional accommodation (High/Unconditional) were more effective in improving housing stability compared to basic support alongside unconditional housing (Basic/Unconditional) (ES=1.10, 95% confidence interval [CI] [0.39, 1.82]), and in comparison to a no-intervention control group (ES=0.62, 95% CI [0.19, 1.06]). A second NMA on health outcomes demonstrates that interventions categorised as offering Moderate/Conditional (ES= 0.36, 95% CI [0.03, 0.69]) and High/Unconditional (ES = 0.22, 95% CI [0.01, 0.43]) support were effective in improving health outcomes compared to no intervention. These effects were smaller than those observed for housing stability. The quality of the evidence was relatively low but varied across the 28 included studies. Depending on the context, finding accommodation for those who need it can be hindered by supply and affordability in the market. The social welfare approach in each jurisdiction can impact heavily on support available and can influence some of the prejudice and stigma surrounding homelessness. The evaluations emphasised the need for collaboration and a shared commitment between policymakers, funders and practitioners which creates community and buy in across sectors and agencies. However, co-ordinating this is difficult and requires sustainability to work. For those implementing programmes, it was important to invest time in developing a culture together to build trust and solid relationships. Additionally, identifying sufficient resources and appropriate referral routes allows for better implementation planning. Involving staff and case workers in creating processes helps drive enthusiasm and energy for the service. Time should be allocated for staff to develop key skills and communicate engage effectively with service users. Finally, staff need time to develop trust and relationships with service users; this goes hand in hand with providing information that is up to date and useful as well making themselves accessible in terms of location and time.

Authors' Conclusions

The network meta-analysis suggests that all types of accommodation which provided support are more effective than no intervention or Basic/Unconditional accommodation in terms of housing stability and health. The qualitative evidence synthesis raised a primary issue in relation to context: which was the lack of stable, affordable accommodation and the variability in the rental market, such that actually sourcing accommodation to provide for individuals who are homeless is extremely challenging. Collaboration between stakeholders and practitioners can be fruitful but difficult to coordinate across different agencies and organisations.

Gingival Fibroma: An Emerging Distinct Gingival Lesion with Well-Defined Histopathology

Gingival growths, barring a few are mostly reactive and seldom exhibit significant true neoplastic potential. The common etiology is local irritation from dental plaque/calculus, trauma as well as medication-related overgrowth. Such lesions are easily distinguishable and categorized into diagnoses such as pyogenic granuloma, peripheral ossifying fibroma, etc. We present a previously undescribed, but commonly encountered, reactive gingival growth with unique histologic features and suggest the diagnostic term "gingival fibroma." An IRB approved retrospective review of the University of Florida Oral Pathology Biopsy Service encompassing years 2010-2019, was performed to select cases. Demographics, clinical data, and microscopic diagnoses were recorded and analyzed. Four board-certified oral and maxillofacial pathologists agreed upon and established the diagnostic criteria. These are: a prominent fibromyxoid stroma, variable cellularity, a whorled or storiform pattern of arrangement of the cellular elements, lack of significant inflammation or vascularity, and complete absence of calcification, and/or odontogenic islands. A total of 60 cases met all criteria and were included in the study. Age range in years was 14-87 with the mean at 45.11 years. A striking female predilection (90%) was noted. Approximately 62% of cases were reported on the maxillary gingiva, followed by 38.3% in the mandibular gingiva. Majority, 66.7% were in the anterior incisor region followed by 11.7% in the canine/first premolar areas. All lesions were submitted as excisional biopsy, and 4 cases recurred within 2-3 years of excision. In all cases, lesional tissue appeared to extend to the surgical base of the specimen. We present 60 cases of a histologically unique entity occurring exclusively on the gingiva and introduce the diagnostic term "Gingival Fibroma" for these lesions. Further studies with adequate clinical follow-up may help understand the exact clinical behavior of these lesions.

The ACE Index: mapping childhood adversity in England

Background

Studies of adults show that adverse childhood experiences (ACEs) are associated with health and social problems and are more common among people living in deprived areas. However, there is limited information about the geographical pattern of contemporary ACEs.

Methods

We used data from the police, social services, schools and vital statistics in England to calculate population rates of events that represent childhood adversity. We constructed an ‘ACE Index’ that summarizes the relative frequency of ACEs at local authority level, informed by the methods of the Index of Multiple Deprivation. We explored associations between the ACE Index and local characteristics in cross-sectional ecological analysis.

Results

The ACE Index was strongly associated with the proportion of children that live in income-deprived households (child poverty). In addition, the ACE Index was independently associated with higher population density and was higher in certain regions, particularly the north-east.

Conclusions

The association between ACEs and child poverty provides evidence of a process in which deprivation increases the risk of adverse experiences in childhood. The ACE Index can inform allocation of resources for prevention and mitigation of ACEs.

Individuals experiencing chronic homelessness: A 10-year follow-up of a cohort in Spain

With the start of the great economic recession in 2007, homelessness increased fivefold in some regions of southern Europe. Larger numbers of people experiencing homelessness, compounded by a lowered capacity for social and health services to respond to their needs, precipitated an increase in so-called 'chronic homelessness'. The aim of this study was to establish the presence of chronic homelessness in a defined geographical area of Spain, and to determine the prevalence of diagnosed mental disorders within both the chronic and non-chronic homeless population. A prospective and descriptive study was designed to monitor a cohort of 826 individuals experiencing homelessness who constituted the entire identified homeless population in the relevant territory in 2006. This sample was followed until 2016 and sociodemographic as well as clinical information was collected, including the time spent homeless. The results obtained indicated that one in 10 participants met the criteria for chronic homelessness, a rate that is lower than in the US, where the definition of chronicity that was applied originates from. Alcohol use disorder was the most common mental health disorder that contributed to the chronicity associated with homelessness. Being born in the country (Spain) where the study was conducted and being older were the main other variables associated with chronicity. People defined as chronically homeless in Spain were on average younger than in the US, but women were present in the chronic subgroup at a similar rate. We also reflect on the limitations of the study and in particular the appropriateness of the concept of chronicity as applied to homelessness.

Internationalization of read-across as a validated new approach method (NAM) for regulatory toxicology

Read-across (RAx) translates available information from well-characterized chemicals to a substance for which there is a toxicological data gap. The OECD is working on case studies to probe general applicability of RAx, and several regulations (e.g., EU-REACH) already allow this procedure to be used to waive new in vivo tests. The decision to prepare a review on the state of the art of RAx as a tool for risk assessment for regulatory purposes was taken during a workshop with international experts in Ranco, Italy in July 2018. Three major issues were identified that need optimization to allow a higher regulatory acceptance rate of the RAx procedure: (i) the definition of similarity of source and target, (ii) the translation of biological/toxicological activity of source to target in the RAx procedure, and (iii) how to deal with issues of ADME that may differ between source and target. The use of new approach methodologies (NAM) was discussed as one of the most important innovations to improve the acceptability of RAx. At present, NAM data may be used to confirm chemical and toxicological similarity. In the future, the use of NAM may be broadened to fully characterize the hazard and toxicokinetic properties of RAx compounds. Concerning available guidance, documents on Good Read-Across Practice (GRAP) and on best practices to perform and evaluate the RAx process were identified. Here, in particular, the RAx guidance, being worked out by the European Commission’s H2020 project EU-ToxRisk together with many external partners with regulatory experience, is given.

PROTOCOL: Studies of the effectiveness of interventions to improve the welfare of those affected by, and at risk of, homelessness in high-income countries: An evidence and gap map

Homelessness - people living on the street, in temporary accommodation, or at risk of losing their homes - is a persistent problem across the developed world. Policies and programmes to tackle homelessness should be informed by evidence of effectiveness. This is the protocol for an evidence and gap map for studies of the effectiveness of interventions to improve the welfare of those experiencing homelessness or at risk of homelessness. We proposed a comprehensive search for studies, with systematic screening, coding and reporting. The available studies will be presented in an online interactive map together with a supporting report.

Cadmium: Mitigation strategies to reduce dietary exposure

Abstract

Cadmium has long been recognized as an environmental contaminant that poses risks to human health. Cadmium is of concern since nearly everyone in the general population is exposed to the metal through the food supply and the ability of the element to accumulate in the body over a lifetime. In support of the United States Food and Drug Administration's (FDA) Toxic Element Working Group's efforts to reduce the risks associated with elements in food, this review sought to identify current or new mitigation efforts that have the potential to reduce exposures of cadmium throughout the food supply chain. Cadmium contamination of foods can occur at various stages, including agronomic production, processing, and consumer preparation for consumption. The presence of cadmium in food is variable and dependent on the geographical location, the bioavailability of cadmium from the soil, crop genetics, agronomic practices used, and postharvest operations. Although there are multiple points in the food supply system for foods to be contaminated and mitigations to be applied, a key step to reducing cadmium in the diet is to reduce or prevent initial uptake by plants consumed as food or feed crops. Due to complex interactions of soil chemistry, plant genetics, and agronomic practices, additional research is needed. Support for field‐based experimentation and testing is needed to inform risk modeling and to develop practical farm‐specific management strategies. This study can also assist the FDA in determining where to focus resources so that research and regulatory efforts can have the greatest impact on reducing cadmium exposures from the food supply.

Practical Application

The presence of cadmium in food is highly variable and highly dependent on the geographical location, the bioavailability of cadmium from the soil, crop genetics, and agronomic practices used. This study can assist the FDA in determining where to focus resources so that research and regulatory efforts can have the greatest impact on reducing cadmium exposures from the food supply.

A review of the evidence to support interim reference level for dietary lead exposure in adults

FDA developed the interim reference level (IRL) for lead of 3 μg/day in children and 12.5 μg/day in women of childbearing age (WOCBA) to better protect the fetus from lead toxicity. These IRLs correspond to a blood lead level (BLL) of 0.5 μg/dL in both populations. The current investigation was performed to determine if the IRL for WOCBA should apply to the general population of adults. A literature review of epidemiological studies was conducted to determine whether a BLL of 0.5 μg/dL is associated with adverse effects in adults. Some studies reported adverse effects over a wide range of BLLs that included 0.5 μg/dL adding uncertainty to conclusions about effects at 0.5 μg/dL; however, no studies clearly identified this BLL as an adverse effect level. Results also showed that the previously developed PTTDI for adults of 75 μg/day lead may not be health protective, supporting use of a lower reference value for lead toxicity in this population group. Use of the 12.5 μg/day IRL as a benchmark for dietary lead intake is one way FDA will ensure that dietary lead intake in adults is reduced.

Lead exposures in older children (males and females 7-17 years), women of childbearing age (females 16-49 years) and adults (males and females 18+ years): FDA total diet study 2014-16

Dietary exposures to lead were estimated for older children, females of childbearing age and adults based on lead concentration data from the FDA's Total Diet Study and on food consumption data from What We Eat In America (WWEIA), the food survey portion of the National Health and Nutrition Examination Survey (NHANES). Estimated mean exposures varied based on the population and on the three different substitution scenarios for lead values below the limit of detection (non-detects = 0; non-detects = limit of detection; hybrid approach). Estimated mean lead exposures range from 1.4 to 4.0 µg/day for older children (males and females 7-17 years), 1.6 to 4.6 µg/day for women of childbearing age (females 16-49 years) and 1.7 to 5.3 µg/day for adults (males and females 18 years and older). Estimated 90th percentile lead exposures range from 2.3 to 5.8 µg/day for older children, 2.8 to 6.7 µg/day for women of childbearing age and 3.2 to 7.8 µg/day for adults. Exposure estimates suggest some older children may be exposed to dietary lead above the FDA interim reference level for lead in children of 3 µg/day. The results of this study can be used by the FDA to prioritise research and regulatory efforts in the area of dietary lead exposure.

Neurosurgical aspects of abusive head trauma management in children: a review for the training neurosurgeon

The management of head trauma in children from suspected abuse is multidisciplinary. The primary role of neurosurgeons is to manage the acute clinical situation. They also have a secondary role in assisting others to determine the cause of the injury and prevent recurrences. This article aims to guide the trainee neurosurgeon on management of this patient group according to current literature.

What works in inclusion health: overview of effective interventions for marginalised and excluded populations

Inclusion health is a service, research, and policy agenda that aims to prevent and redress health and social inequities among the most vulnerable and excluded populations. We did an evidence synthesis of health and social interventions for inclusion health target populations, including people with experiences of homelessness, drug use, imprisonment, and sex work. These populations often have multiple overlapping risk factors and extreme levels of morbidity and mortality. We identified numerous interventions to improve physical and mental health, and substance use; however, evidence is scarce for structural interventions, including housing, employment, and legal support that can prevent exclusion and promote recovery. Dedicated resources and better collaboration with the affected populations are needed to realise the benefits of existing interventions. Research must inform the benefits of early intervention and implementation of policies to address the upstream causes of exclusion, such as adverse childhood experiences and poverty.

Clear cell changes in salivary gland neoplasms: A 20-year retrospective study

BACKGROUND

Clear cells are observed histopathologically in both benign and malignant neoplasms but their presence in salivary gland tumors has not been extensively documented.

MATERIAL AND METHODS

With IRB approval, the archive of the University of Florida College of Dentistry oral pathology biopsy service was retrospectively searched from 1994-2014 for all benign and malignant salivary tumors. Epidemiological data, tumor location and duration, and type of tumor were recorded. A four reviewer panel examined the original slides. Reviewers scaled each case as 0 (no clear cells present), 1 (few to focal clear cells), 2 (less than 50% clear cells), and 3 (greater than 50% clear cells).

RESULTS

A total of 535 cases were included of which 48% of tumors displayed 0 clear cells (257/535), 31.4% (168/535) scored 1, 13.6% (73/535) scored 2, and 7% (37/535) scored 3. Of the 251 (47%) malignant neoplasms, 64% (160/251) demonstrated 0-1 clear cell change, while 36% (91/251) showed a score of 2-3. For the total 284 (53%) benign tumors, 93% (265/535) scored 0-1 and 7% (19/535) scored a 2-3 range. No statistical difference was noted for gender, age, or duration of time present in regards to presence or absence of clear cells. Statistically significant differences in clear cell presence were found between location groups, between benign and malignant diagnosis, and between specific diagnostic groups.

CONCLUSIONS

This study demonstrates the frequent presence of increased numbers of clear cells in oral salivary malignancies and highlights salivary gland differential diagnoses when presented with clear cell changes.

The Emergence of Systematic Review in Toxicology

The Evidence-based Toxicology Collaboration hosted a workshop on "The Emergence of Systematic Review and Related Evidence-based Approaches in Toxicology," on November 21, 2014 in Baltimore, Maryland. The workshop featured speakers from agencies and organizations applying systematic review approaches to questions in toxicology, speakers with experience in conducting systematic reviews in medicine and healthcare, and stakeholders in industry, government, academia, and non-governmental organizations. Based on the workshop presentations and discussion, here we address the state of systematic review methods in toxicology, historical antecedents in both medicine and toxicology, challenges to the translation of systematic review from medicine to toxicology, and thoughts on the way forward. We conclude with a recommendation that as various agencies and organizations adapt systematic review methods, they continue to work together to ensure that there is a harmonized process for how the basic elements of systematic review methods are applied in toxicology.

Pathways of Toxicity

Despite wide-spread consensus on the need to transform toxicology and risk assessment in order to keep pace with technological and computational changes that have revolutionized the life sciences, there remains much work to be done to achieve the vision of toxicology based on a mechanistic foundation. To this end, a workshop was organized to explore one key aspect of this transformation - the development of Pathways of Toxicity as a key tool for hazard identification based on systems biology. Several issues were discussed in depth in the workshop: The first was the challenge of formally defining the concept of a Pathway of Toxicity (PoT), as distinct from, but complementary to, other toxicological pathway concepts such as mode of action (MoA). The workshop came up with a preliminary definition of PoT as "A molecular definition of cellular processes shown to mediate adverse outcomes of toxicants". It is further recognized that normal physiological pathways exist that maintain homeostasis and these, sufficiently perturbed, can become PoT. Second, the workshop sought to define the adequate public and commercial resources for PoT information, including data, visualization, analyses, tools, and use-cases, as well as the kinds of efforts that will be necessary to enable the creation of such a resource. Third, the workshop explored ways in which systems biology approaches could inform pathway annotation, and which resources are needed and available that can provide relevant PoT information to the diverse user communities.

Evidence-based toxicology for the 21st century: opportunities and challenges

The Evidence-based Toxicology Collaboration (EBTC) was established recently to translate evidence-based approaches from medicine and health care to toxicology in an organized and sustained effort. The EBTC held a workshop on "Evidence-based Toxicology for the 21st Century: Opportunities and Challenges" in Research Triangle Park, North Carolina, USA on January 24-25, 2012. The presentations largely reflected two EBTC priorities: to apply evidence-based methods to assessing the performance of emerging pathway-based testing methods consistent with the 2007 National Research Council report on "Toxicity Testing in the 21st Century" as well as to adopt a governance structure and work processes to move that effort forward. The workshop served to clarify evidence-based approaches and to provide food for thought on substantive and administrative activities for the EBTC. Priority activities include conducting pilot studies to demonstrate the value of evidence-based approaches to toxicology, as well as conducting educational outreach on these approaches.