Dose Volume Thresholds Associated with Acute Skin Toxicities in Proton Beam Therapy

PURPOSE/OBJECTIVE(S)

The depth-dose characteristics of proton beam therapy (PBT) mean that the skin-sparing effect is reduced with PBT, potentially leading to an increased incidence and severity of acute radiotherapy induced skin toxicities (RIST). Predictive factors of acute RIST in patients treated with PBT remain largely undefined. In this study, we retrospectively reviewed the acute RIST of patients treated with pencil beam scanning (PBS) PBT to identify dose-volume thresholds which are predictive of acute RIST.

MATERIALS/METHODS

All patients treated with PBS-PBT at a single institution between December 2018-October 2022 were included in this study. Acute RIST were recorded as per RTOG grading scale and dichotomized to Grade (G) <2 vs ≥2. Anonymized demographics, clinical and dosimetric data were extracted from electronic patient records and a treatment planning system. Skin structure is defined as 5mm rind grown as an inner margin from the patient contour. The following skin dose-volume statistics were collected: Dmax (maximum dose to any pixel inside the skin contour) and dose to skin volumes in 5Gy increments (V5Gy, V10Gy etc.). Preliminary analyses of dosimetric data of patients with G0, G1 vs ≥G2 acute RIST are presented, with significance assessed at the 5% level using t-tests and univariate logistic regression models, and risk thresholds determined using receiver operating characteristic (ROC) curves.

RESULTS

We report the data for 582 patients with extracted dosimetric data. The pediatric, teenage and young adult (TYA) and adult populations were 38%, 19% and 43% respectively. The three most common indications for PBT were head and neck cancers (HNC) (23%), sarcoma (21%), and chordoma (15%). Increasing age, HNC and sarcoma were associated with an increased risk of grade 2+ acute RIST. For patients who developed acute RIST of G2+, the median volume receiving 10Gy, 20Gy, 30Gy, 40Gy and 50Gy were significantly higher (P<0.0001) than patients with G0 and G1. The dose volume effect of acute RIST is greater at 30Gy and above. Similarly, median Dmax was significantly higher in the G2+ acute RIST group compared to G0 and G1 (P<0.0001) for all age groups. Using the ROC curve, we observed threshold volumes (in cm3) for V10Gy, V20Gy, V30Gy, V40Gy and V50Gy (Table 1).

CONCLUSION

The volume of irradiated skin and Dmax are associated with the risk of developing acute RIST in patients treated with PBS PBT. Further work is being done to develop a model predictive of acute RIST in clinical setting.

OECD harmonised template 201: Structuring and reporting mechanistic information to foster the integration of new approach methodologies for hazard and risk assessment of chemicals

In the European Union, the Chemicals Strategy for Sustainability (CSS) highlights the need to enhance the identification and assessment of substances of concern while reducing animal testing, thus fostering the development and use of New Approach Methodologies (NAMs) such as in silico, in vitro and in chemico. In the United States, the Tox21 strategy aims at shifting toxicological assessments away from traditional animal studies towards target-specific, mechanism-based and biological observations mainly obtained by using NAMs. Many other jurisdictions around the world are also increasing the use of NAMs. Hence, the provision of dedicated non-animal toxicological data and reporting formats as a basis for chemical risk assessment is necessary. Harmonising data reporting is crucial when aiming at re-using and sharing data for chemical risk assessment across jurisdictions. The OECD has developed a series of OECD Harmonised Templates (OHT), which are standard data formats designed for reporting information used for the risk assessment of chemicals relevant to their intrinsic properties, including effects on human health (e.g., toxicokinetics, skin sensitisation, repeated dose toxicity) and the environment (e.g., toxicity to test species and wildlife, biodegradation in soil, metabolism of residues in crops). The objective of this paper is to demonstrate the applicability of the OHT standard format for reporting information under various chemical risk assessment regimes, and to provide users with practical guidance on the use of OHT 201, in particular to report test results on intermediate effects and mechanistic information.

Expert consensus on neurodevelopmental outcomes in pregnancy pharmacovigilance studies

Background: Exposure in utero to certain medications can disrupt processes of fetal development, including brain development, leading to a continuum of neurodevelopmental difficulties. Recognizing the deficiency of neurodevelopmental investigations within pregnancy pharmacovigilance, an international Neurodevelopmental Expert Working Group was convened to achieve consensus regarding the core neurodevelopmental outcomes, optimization of methodological approaches and barriers to conducting pregnancy pharmacovigilance studies with neurodevelopmental outcomes. Methods: A modified Delphi study was undertaken based on stakeholder and expert input. Stakeholders (patient, pharmaceutical, academic and regulatory) were invited to define topics, pertaining to neurodevelopmental investigations in medication-exposed pregnancies. Experts were identified for their experience regarding neurodevelopmental outcomes following medicinal, substances of misuse or environmental exposures in utero. Two questionnaire rounds and a virtual discussion meeting were used to explore expert opinion on the topics identified by the stakeholders. Results: Twenty-five experts, from 13 countries and professionally diverse backgrounds took part in the development of 11 recommendations. The recommendations focus on the importance of neurodevelopment as a core feature of pregnancy pharmacovigilance, the timing of study initiation and a core set of distinct but interrelated neurodevelopmental skills or diagnoses which require investigation. Studies should start in infancy with an extended period of investigation into adolescence, with more frequent sampling during rapid periods of development. Additionally, recommendations are made regarding optimal approach to neurodevelopmental outcome measurement, comparator groups, exposure factors, a core set of confounding and mediating variables, attrition, reporting of results and the required improvements in funding for potential later emerging effects. Different study designs will be required depending on the specific neurodevelopmental outcome type under investigation and whether the medicine in question is newly approved or already in widespread use. Conclusion: An improved focus on neurodevelopmental outcomes is required within pregnancy pharmacovigilance. These expert recommendations should be met across a complementary set of studies which converge to form a comprehensive set of evidence regarding neurodevelopmental outcomes in pregnancy pharmacovigilance.

VectorNet: collaborative mapping of arthropod disease vectors in Europe and surrounding areas since 2010

BackgroundArthropod vectors such as ticks, mosquitoes, sandflies and biting midges are of public and veterinary health significance because of the pathogens they can transmit. Understanding their distributions is a key means of assessing risk. VectorNet maps their distribution in the EU and surrounding areas.AimWe aim to describe the methodology underlying VectorNet maps, encourage standardisation and evaluate output.Methods: Vector distribution and surveillance activity data have been collected since 2010 from a combination of literature searches, field-survey data by entomologist volunteers via a network facilitated for each participating country and expert validation. Data were collated by VectorNet members and extensively validated during data entry and mapping processes.ResultsAs of 2021, the VectorNet archive consisted of ca 475,000 records relating to > 330 species. Maps for 42 species are routinely produced online at subnational administrative unit resolution. On VectorNet maps, there are relatively few areas where surveillance has been recorded but there are no distribution data. Comparison with other continental databases, namely the Global Biodiversity Information Facility and VectorBase show that VectorNet has 5-10 times as many records overall, although three species are better represented in the other databases. In addition, VectorNet maps show where species are absent. VectorNet's impact as assessed by citations (ca 60 per year) and web statistics (58,000 views) is substantial and its maps are widely used as reference material by professionals and the public.ConclusionVectorNet maps are the pre-eminent source of rigorously validated arthropod vector maps for Europe and its surrounding areas.

A Reflection on the Tensions of Acting in Dual Roles of Doctoral Researcher and Practitioner when Evaluating a Lifestyle Intervention for Breast Cancer Patients

This reflection was completed as part of a doctoral project to develop and trial a lifestyle intervention for people following the completion of their treatment for breast cancer. In this study the graduate student acted in the dual roles of nutrition practitioner and researcher. This article uses the experience, reflection, action (ERA) cycle of reflection to consider some of the tensions faced due to the divergent priorities and requirements of these two roles. One challenge occurred during study recruitment when a few potential participants did not meet the inclusion criteria for the study but still wished to attend the intervention sessions. It was also a challenge to mitigate the risks of distress of potentially vulnerable participants during group intervention sessions. In both instances there was a potential conflict between the needs of patients and research requirements. This reflection concluded that the obligations of both roles should be adhered to where possible, but if in doubt, the needs of the participants were paramount.

Characterizing posttraumatic stress disorder in primary care using electronic medical records: a retrospective cohort study

Context

Posttraumatic stress disorder (PTSD) is a chronic mental health disorder associated with significant morbidity and economic cost. Primary care providers are frequently involved in the ongoing management of patients experiencing PTSD, as well as related comorbid conditions. Despite recognized need to enhance PTSD management in primary care settings, knowledge regarding its prevalence in these settings is limited.

Objective

To apply a validated case definition of PTSD to electronic medical records (EMRs) of family physicians and nurse practitioners participating in the Canadian Primary Care Sentinel Surveillance Network (CPCSSN).

Study Design

Retrospective cross-sectional study.

Dataset

This study accessed de-identified EMR from 1,574 primary care providers participating in the CPCSSN.

Population Studied

The study population included all patients with at least one visit to a primary care provider participating in the CPCSSN between January 1, 2017 and December 31, 2019 (N = 689,301).

Outcome Measures

We identified patients with PTSD and described associations between PTSD and patient characteristics (including sex, age, geography, depression, anxiety, medical comorbidities, substance use and social and material deprivation) using multivariable logistic regression models.

Results

Among the 689,301 patients meeting inclusion criteria, 8,213 (1.2%) had a diagnosis of PTSD. Patients with PTSD were significantly more likely to reside in an urban location (84.9% vs. 80.4%; p-value <.0001) and have one or more comorbid conditions (90.8% vs. 70.2%; p-value <.0001). On multivariable logistic regression analysis, patients with depression (OR 4.8; 95%CI 4.6-5.1) and anxiety (OR 2.2; 95%CI 2.1-2.3) had increased odds of having PTSD compared to patients without depression or anxiety. Patients with alcohol (OR 1.8; 95%CI 1.6-1.9) and drug (OR 3.1; 95%CI 2.9-3.3) use disorders had significantly higher odds of PTSD compared to patients without these disorders. Patients in the most deprived neighborhoods based on census data had 4.2 times higher odds of have PTSD (95%CI 3.2-5.43) compared to patients in the least deprived areas.

Conclusions

This is the first study to describe PTSD prevalence in a large Canadian sample of primary care patients using an EMR-based case definition. Characterizing patients with PTSD in primary care may improve disease surveillance and inform the interdisciplinary care required to manage PTSD symptoms.

A treatment planning comparison of photon stereotactic ablative radiotherapy and proton beam therapy for the re-irradiation of pelvic cancer recurrence

BACKGROUND

Patients who experience a pelvic cancer recurrence in or near a region that received initial radiotherapy, typically have few options for treatment. Organs at risk (OAR) have often reached their dose constraint limits leaving minimal dose remaining for standard re-irradiation (reRT). However, photon based stereotactic ablative radiotherapy (SABR) has been utilised for reRT with promising initial results although meeting OAR constraints can be challenging. Proton beam therapy (PBT) could offer an advantage.

MATERIALS AND METHODS

SABR plans used for treatment for ten pelvic reRT patients were dosimetrically compared to PBT plans retrospectively planned using the same CT and contour data. PBT plans were created to match the CTV dose coverage of SABR treatment plans with V100% ≥95%. An 'as low as reasonably achievable' approach was taken to OAR tolerances with consideration of OAR dose from the initial radiation (using equivalent dose in 2 Gy fractions).

RESULTS

Dosimetric comparison of relevant OAR statistics showed a decrease in OAR dose using PBT over SABR in all patients, with equivalent target coverage. The largest statistically significant reduction was seen for the colon D0.5 cm3 with a median reduction from 13.1 Gy to 5.9 Gy. There were statistically significant dose reductions in the median dose to small bowel, sacral plexus and cauda equina.

CONCLUSION

PBT has the potential for significant dose reductions for OARs in the pelvic reRT setting compared to SABR. However, it remains unclear if the magnitude of these OAR dose reductions will translate into clinical benefit.

Alzheimer's Disease Prevention Health Coaching

Background

Results

Conclusions

Reliability of Addenbrooke's Cognitive Examination III in differentiating between dementia, mild cognitive impairment and older adults who have not reported cognitive problems

Diagnosing dementia can be challenging for clinicians, given the array of factors that contribute to changes in cognitive function. The Addenbrooke’s Cognitive Examination III (ACE-III) is commonly used in dementia assessments, covering the domains of attention, memory, fluency, visuospatial and language. This study aims to (1) assess the reliability of ACE-III to differentiate between dementia, mild cognitive impairment (MCI) and controls and (2) establish whether the ACE-III is useful for diagnosing dementia subtypes. Client records from the Northern Health and Social Care Trust (NHSCT) Memory Service (n = 2,331, 2013–2019) were used in the analysis including people diagnosed with Alzheimer’s disease (n = 637), vascular dementia (n = 252), mixed dementia (n = 490), MCI (n = 920) and controls (n = 32). There were significant differences in total ACE-III and subdomain scores between people with dementia, MCI and controls (p < 0.05 for all), with little overlap between distribution of total ACE-III scores (< 39%) between groups. The distribution of total ACE-III and subdomain scores across all dementias were similar. There were significant differences in scores for attention, memory and fluency between Alzheimer’s disease and mixed dementia, and for visuospatial and language between Alzheimer’s disease–vascular dementia (p < 0.05 for all). However, despite the significant differences across these subdomains, there was a high degree of overlap between these scores (> 73%) and thus the differences are not clinically relevant. The results suggest that ACE-III is a useful tool for discriminating between dementia, MCI and controls, but it is not reliable for discriminating between dementia subtypes. Nonetheless, the ACE-III is still a reliable tool for clinicians that can assist in making a dementia diagnosis in combination with other factors at assessment.

Femoral condylar fractures in four continental giant breed rabbits

Four male neutered continental giant rabbits aged between 10 and 30 months were presented with femoral condylar fractures, which developed without an observed traumatic injury. Stabilisation of the condylar fracture was achieved with screw fixation in all cases, which was supplemented with additional fixation in three cases. Complications consequent to the surgical intervention occurred in two cases: a femoral fracture and loss of fixation. Three rabbits were reported to have recovered normal limb function, and the rabbit that developed a femoral fracture as a consequence of its surgical intervention was treated with amputation.

Skin Toxicity Profile of Photon Radiotherapy versus Proton Beam Therapy in Paediatric and Young Adult Patients with Sarcomas

AIMS

Radiotherapy is key in the management of patients with both Ewing sarcoma and rhabdomyosarcoma. However, there is little evidence in the literature with regards to radiation-induced skin toxicities (RISTs) for patients treated with conventional radiotherapy with X-rays (XRT) or proton beam therapy (PBT) for these two conditions. In the present study we evaluated acute and late RIST in patients treated within European protocols with either PBT or XRT, taking both clinical and dosimetric variables into consideration.

MATERIALS AND METHODS

This was a retrospective analysis of 79 paediatric/young adult patients treated with radical radiotherapy (with XRT or PBT) and concurrent chemotherapy. In all cases, radiotherapy was given in conventional fractionation (1.8 Gy/fraction). Acute and late RISTs were registered according to the Radiation Therapy Oncology Group (RTOG) scoring system.

RESULTS

With regards to acute RIST, 47.9% (23/48) of XRT patients and 48.4% (15/31) of PBT patients had acute grade 2/3 toxicity. When it comes to late RIST, 17.5% (7/40 with known toxicity profile) of XRT patients and 29.0% (9/31) of PBT patients had grade 1/2 toxicity. This difference of -11.5% (95% confidence interval -31.2 to 7.9%) in grade 1/2 toxicity between XRT and PBT was not statistically significant (P = 0.25). Regardless of the radiotherapy technique, V30Gy seems a good predictor of acute RIST. Moreover, for the same value of V30Gy, patients who receive PBT may have a higher risk of moderate-severe acute RIST. Perhaps due to the small sample, definitive conclusions on the predictive factors of late RIST could not be drawn.

CONCLUSIONS

No clinically meaningful differences in acute and late RIST were observed between PBT and XRT subgroups. Systematic differences in the modelling of the build-up region may exist between XRT and PBT algorithms, which could make the comparison of dose metrics between techniques potentially biased. A more comprehensive analysis of dosimetric data on larger patient cohorts is needed to elucidate the most relevant skin dose metrics. Dose-effect models of RIST for this unique patient population would be an invaluable tool in radiotherapy plan optimisation.

The Effects of a Walking Intervention on Gait Parameters in Older Adults Residing in Long-Term Care: A Randomized Controlled Trial

OBJECTIVES

We examined the effects of a walking intervention in older adults residing in long-term care (LTC) homes on gait velocity (primary outcome), and stride length, cadence and heel-to-heel base of support (secondary outcomes) compared to those in an interpersonal interaction control group and a care-as-usual control group at 16-weeks post-intervention.

METHODS

These previously unpublished gait data were collected as part of a larger prospective, randomized, three group study. One hundred and sixty-eight participants residing in 12 LTC homes were randomized into: a) a walking group (n=57) - 1:1 supervised, individualized, progressive, 30 minutes, five times a week walking program for 16 weeks; b) an interpersonal interaction group (n=55) - stationary 1:1 conversation time with research personnel; and, c) a care-as-usual control group (n=56). Gait was assessed at baseline and 16-weeks post-intervention using the GAITRite® computerized system. One-way Analysis of Covariance (ANCOVA), controlling for age, sex, cognitive status and baseline gait parameter (velocity, stride length, cadence, heel-to-heel base of support) was used to examine differences among groups for velocity, stride length, cadence, and heel-to-heel base of support at 16-weeks post-intervention.

RESULTS

Ninety-one participants with available data were included in this analysis: walking group (n=31/57, mean age=82.77±6.75 years); interpersonal interaction group (n=31/55, mean age=82.74±9.27 years); care-as-usual control group (n=29/56, mean age=85.40±8.78 years). ANCOVA showed a significant difference in the mean gait velocity at 16-weeks post-intervention [F(2, 84) =6.99, p=0.0006); η2 (95%CI)=0.16 (0.02, 0.27)]. Post hoc comparisons using Sidak test showed that the estimated marginal mean (EMM) for velocity for the walking group [EMM (SE), 0.51m/s (0.03)] was significantly higher compared to the interpersonal interaction group [EMM (SE), 0.38m/s (0.03); t(83)=3.15, p=0.007] and the care-as-usual control group [EMM (SE), 0.38m/s (0.03)]; t(83)=3.32, p=0.004]. No significant difference was observed between groups for stride length, cadence or heel-to-heel base of support.

CONCLUSION

LTC residents with limited physical functioning showed significant improvement in gait velocity but not in stride length, cadence or heel-to-heel base of support after a 16-week walking intervention.

EFSA's OpenFoodTox: An open source toxicological database on chemicals in food and feed and its future developments

Since its creation in 2002, the European Food Safety Authority (EFSA) has produced risk assessments for over 5000 substances in >2000 Scientific Opinions, Statements and Conclusions through the work of its Scientific Panels, Units and Scientific Committee. OpenFoodTox is an open source toxicological database, available both for download and data visualisation which provides data for all substances evaluated by EFSA including substance characterisation, links to EFSA's outputs, applicable legislations regulations, and a summary of hazard identification and hazard characterisation data for human health, animal health and ecological assessments. The database has been structured using OECD harmonised templates for reporting chemical test summaries (OHTs) to facilitate data sharing with stakeholders with an interest in chemical risk assessment, such as sister agencies, international scientific advisory bodies, and others. This manuscript provides a description of OpenFoodTox including data model, content and tools to download and search the database. Examples of applications of OpenFoodTox in chemical risk assessment are discussed including new quantitative structure-activity relationship (QSAR) models, integration into tools (OECD QSAR Toolbox and AMBIT-2.0), assessment of environmental footprints and testing of threshold of toxicological concern (TTC) values for food related compounds. Finally, future developments for OpenFoodTox 2.0 include the integration of new properties, such as physico-chemical properties, exposure data, toxicokinetic information; and the future integration within in silico modelling platforms such as QSAR models and physiologically-based kinetic models. Such structured in vivo, in vitro and in silico hazard data provide different lines of evidence which can be assembled, weighed and integrated using harmonised Weight of Evidence approaches to support the use of New Approach Methodologies (NAMs) in chemical risk assessment and the reduction of animal testing.

Making the invisible enemy visible

During the COVID-19 pandemic, structural biologists rushed to solve the structures of the 28 proteins encoded by the SARS-CoV-2 genome in order to understand the viral life cycle and enable structure-based drug design. In addition to the 204 previously solved structures from SARS-CoV-1, 548 structures covering 16 of the SARS-CoV-2 viral proteins have been released in a span of only 6 months. These structural models serve as the basis for research to understand how the virus hijacks human cells, for structure-based drug design, and to aid in the development of vaccines. However, errors often occur in even the most careful structure determination - and may be even more common among these structures, which were solved quickly and under immense pressure. The Coronavirus Structural Task Force has responded to this challenge by rapidly categorizing, evaluating and reviewing all of these experimental protein structures in order to help downstream users and original authors. In addition, the Task Force provided improved models for key structures online, which have been used by Folding@Home, OpenPandemics, the EU JEDI COVID-19 challenge and others.

Have whales returned to a historical hotspot of industrial whaling? The pattern of southern right whale Eubalaena australis recovery at South Georgia

Around 176500 whales were killed in the sub-Antarctic waters off South Georgia (South Atlantic) between 1904 and 1965. In recent decades, whales have once again become summer visitors, with the southern right whale (SRW) the most commonly reported species until 2011. Here, we assess the distribution, temporal pattern, health status and likely prey of SRWs in these waters, combining observations from a summertime vessel-based expedition to South Georgia, stable isotope data collected from SRWs and putative prey and sightings reports collated by the South Georgia Museum. The expedition used directional acoustics and visual surveys to localise whales and collected skin biopsies and photo-IDs. During 76 h of visual observation effort over 19 expedition days, SRWs were encountered 15 times (~31 individuals). Photo-IDs, combined with publicly contributed images from commercial vessels, were reconciled and quality-controlled to form a catalogue of 6 fully (i.e. both sides) identified SRWs and 26 SRWs identified by either left or right sides. No photo-ID matches were found with lower-latitude calving grounds, but 3 whales had gull lesions supporting a direct link with Península Valdés, Argentina. The isotopic position of SRWs in the South Georgia food web suggests feeding on a combination of copepod and krill species. Opportunistic reports of SRW sightings and associated group sizes remain steady over time, while humpback whales provide a strong contrast, with increased sighting rates and group sizes seen since 2013. These data suggest a plateau in SRWs and an increasing humpback whale presence in South Georgia waters following the cessation of whaling.

Dentists' perceptions of their professional roles regarding referrals within primary dental care in England: a qualitative study

OBJECTIVE

To describe dentists' perceptions of their professional roles, including the reasons why they make, accept or decline patient referrals within primary dental care in England.

BASIC RESEARCH DESIGN

Qualitative semi-structured interviews, conducted via Skype, telephone or face-to-face. Transcripts were analysed using thematic analysis and typologies were developed.

PARTICIPANTS

Ten general dental practitioners (GDPs) and 12 community dentists working in England.

RESULTS

Five main themes were identified: professional independence, the nature of dental care, the business of dentistry, obscure rules and 'no man's land'. This final theme described a notional gap between GDPs' and community dentists' responsibilities towards vulnerable people, who were perceived by participants to include frail older people, anxious and socially marginalised adults and children with high levels of disease. Three typologies of dentists were generated. 'Entrepreneurs' felt no allegiance to the National Health Service and no obligation to treat vulnerable patients. 'Altruistic carers' were committed to caring for exceptionally deserving patients. 'Pragmatic carers' tried to provide relational dental care (time and emotional support) for vulnerable patients but encountered discouraging systemic barriers.

CONCLUSION

Dentists' perceptions of their roles may influence whether and how they provide access to primary dental care for vulnerable people through referral systems. Access issues may exacerbate the oral health inequalities experienced by vulnerable groups. Based upon the findings, approaches are proposed that may encourage and enable the dental workforce to support vulnerable people actively to receive primary dental care.

Three Classes of Change to Improve the Daily Living Skills of Persons with Visual Impairment

Individuals who become visually impaired need to adapt in the way they perform tasks. This article describes three classes of change involved in improving the daily living skills of persons with visual impairments: changes in the work, in the workplace, and in the worker's activity. Changes in the work or product are considered the highest level of change and, of necessity, bring about changes in the workplace and in the worker's activities. Case studies illustrate the three levels of changes.

Modifiable factors related to life-space mobility in community-dwelling older adults: results from the Canadian Longitudinal Study on Aging

BACKGROUND

The most common methods for measuring mobility in older adulthood include performance-based tests, such as the Timed-Up-and-Go and gait speed. While these measures have strong predictive validity for adverse outcomes, they are limited to assessing what older adults do in standardized settings, rather than what they do in their daily life. Life-space mobility, which is the ability to move within environments that expand from one's home to the greater community, has been proposed as a more comprehensive measure of mobility. The aim of this study was to determine the association between modifiable factors and life-space mobility in older adults enrolled in the Canadian Longitudinal Study on Aging (CLSA).

METHODS

Life-space mobility was measured using the Life Space Index (LSI). Explanatory factors included physical, psychosocial and cognitive determinants, as well as pain, fatigue, driving status, nutrition, body mass index, smoking status, and vision. To estimate the association between the LSI and explanatory variables, univariate and multivariable ordinary least squares regression analyses were performed.

RESULTS

All adults 65 years and older (n = 12,646) were included in the analysis. Fifty percent were women and the mean age was 73.0 (SD5.7). The mean LSI score was 80.5, indicating that, on average, the sample was able to move outside of their neighborhood independently. All explanatory variables were significantly associated with the LSI except for balance and memory. The top 3 variables that explained the most variation in the LSI were driving, social support and walking speed.

CONCLUSION

To our knowledge, this was the first study to examine the association between life-space mobility and a comprehensive set of modifiable factors that were selected based on a theoretical framework and existing research evidence. This study had two important messages. First, driving, social support and walking speed emerged as the most significant correlates of life-space mobility in older adults. Second, life-space mobility is multifactorial and interventions that are pragmatic in their design and testing are needed that consider the complexity involved. A multi-disciplinary approach to examining life-space mobility in older adults is needed to optimize opportunities for healthy aging and develop strategies that support mobility in older adulthood.

Presentation, treatment and outcome of long-bone fractures in pet rabbits (Oryctolagus cuniculus)

OBJECTIVES

To describe the incidence, aetiology, characteristics, assessment, management and outcome of long-bone fractures in rabbits presenting to a single institution.

MATERIALS AND METHODS

Medical records of pet rabbits diagnosed with long-bone fractures over a 12-year period were analysed. Patient signalment, fracture aetiology, fracture location, fracture description, time from fracture occurrence to veterinary presentation, fixation method, postoperative complications, clinical outcome and follow-up were recorded.

RESULTS

Twenty-eight pet rabbits that sustained 30 fractures were included in the study [femoral (n=12), tibial (n=6), metacarpal/metatarsal/phalangeal (n=5), radial and ulnar (n=4) and tarsal (n=3)]. Twenty-one (75%) of the rabbits were less than 2 years of age, including seven (25%) under 6 months of age. Twenty-five fractures had no identifiable cause and five were traumatic. Only one fracture was open. Surgical stabilisation was performed in 22 fractures, four were non-surgically managed, two had the affected limb amputated, one underwent digital amputation and one was euthanased. Postoperative complications occurred in nine fractures [major (n=6), minor (n=3)]. The frequency of complications or attainment of a functional recovery was not notably different between the different methods of fixation. Overall, 24 rabbits recovered, two were euthanased and four underwent limb amputation.

CLINICAL SIGNIFICANCE

Fractures in rabbits typically occur in young animals and they usually lack an obvious aetiology. The majority of the rabbits treated achieved a functional recovery, although the postoperative complication rate was high in fractures treated surgically (41%).

Managing evidence in food safety and nutrition

Evidence (‘data’) is at the heart of EFSA's 2020 Strategy and is addressed in three of its operational objectives: (1) adopt an open data approach, (2) improve data interoperability to facilitate data exchange, and (3) migrate towards structured scientific data. As the generation and availability of data have increased exponentially in the last decade, potentially providing a much larger evidence base for risk assessments, it is envisaged that the acquisition and management of evidence to support future food safety risk assessments will be a dominant feature of EFSA's future strategy. During the breakout session on ‘Managing evidence’ of EFSA's third Scientific Conference ‘Science, Food, Society’, current challenges and future developments were discussed in evidence management applied to food safety risk assessment, accounting for the increased volume of evidence available as well as the increased IT capabilities to access and analyse it. This paper reports on presentations given and discussions held during the session, which were centred around the following three main topics: (1) (big) data availability and (big) data connection, (2) problem formulation and (3) evidence integration.

Position statement on defining and standardizing an oncoplastic approach to breast-conserving surgery in Canada

Although mastectomy is an effective procedure, it can have a negative effect on body image, sense of attractiveness, and sexuality. As opposed to the combination of breast oncologic surgery and plastic surgery, whose primary focus is on replacing lost volume, breast-conserving oncoplastic surgery (ops) redistributes remaining breast tissue in a manner that requires vision, anatomic knowledge, and an appreciation of esthetics, symmetry, and breast function. Modern surgical treatment of breast cancer can be realized only with breast and plastic surgeons working together using oncoplastic techniques to deliver superior cosmetic and cancer outcomes alike. Using this collaborative approach, oncologic and plastic surgeons in Canada have a significant opportunity to improve the care of their breast cancer patients. We propose a tri-level classification for volume displacement procedures to act as a rubric for the training of general surgeons and oncologic breast surgeons in oncoplastic breast-conserving therapy techniques. It is our position that ops enhances outcomes for many women with breast cancer and should become part of the standard repertoire of procedures used by Canadian oncologic surgeons treating breast cancer.

Abstract P5-04-19: Withdrawn

This abstract was withdrawn by the authors.

Citation Format: Ghassemifar S, Finn G, Zhang H, Richardson J, Kuesters G, Santillana S, Pipas M. Withdrawn [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P5-04-19.

Modelling of vapour intrusion into a building impacted by a fuel spill in Antarctica

A new vapour intrusion contaminant transport model was designed specifically to allow an assessment of the impact of a hydrocarbon fuel spill on air quality in cold region buildings. The model is applied to a recent situation in Antarctica, where a diesel spill impacted the construction of a new building. For the first time, this model allows consideration of the diffusive resistance of different vapour barrier to the transport of hydrocarbons into the building and an assessment of the effectiveness of different products. Site specific indoor air criteria are derived. Five scenarios are modelled at field temperatures: (1) build on current contaminated site; (2) excavate contaminated soil, backfill with clean soil and assess impact of residual contamination; (3) excavate and backfill with remediated (biopile) soil; (4) backfill with remediated soil and assess impact of residual contamination; (5) backfill with remediated soil and assess impact of a potential future fuel spill. Two different vapour barriers, a co-extruded ethylene vinyl alcohol (EVOH) geomembrane (VB1) and a linear low-density (LLDPE) geomembrane (VB2), are investigated for each scenario and compared to a base case with no vapour barrier, providing quantifiable evidence of the benefit of installing an engineered vapour barrier Contaminant concentrations were below regulatory limits for Scenarios (2-5) with VB1 and air exchange in the building. For all scenarios, the EVOH geomembrane (VB1) was consistently superior at reducing vapour transport into the building indoor air space over the LLDPE geomembrane (VB2) and no vapour barrier. The risk mitigation measures developed for this contaminated Antarctic site may be relevant for other buildings in cold regions.

Constructing atomic structural models into cryo-EM densities using molecular dynamics - Pros and cons

Accurate structure determination from electron density maps at 3-5 Å resolution necessitates a balance between extensive global and local sampling of atomistic models, yet with the stereochemical correctness of backbone and sidechain geometries. Molecular Dynamics Flexible Fitting (MDFF), particularly through a resolution-exchange scheme, ReMDFF, provides a robust way of achieving this balance for hybrid structure determination. Employing two high-resolution density maps, namely that of β-galactosidase at 3.2 Å and TRPV1 at 3.4 Å, we showcase the quality of ReMDFF-generated models, comparing them against ones submitted by independent research groups for the 2015-2016 Cryo-EM Model Challenge. This comparison offers a clear evaluation of ReMDFF's strengths and shortcomings, and those of data-guided real-space refinements in general. ReMDFF results scored highly on the various metric for judging the quality-of-fit and quality-of-model. However, some systematic discrepancies are also noted employing a Molprobity analysis, that are reproducible across multiple competition entries. A space of key refinement parameters is explored within ReMDFF to observe their impact within the final model. Choice of force field parameters and initial model seem to have the most significant impact on ReMDFF model-quality. To this end, very recently developed CHARMM36m force field parameters provide now more refined ReMDFF models than the ones originally submitted to the Cryo-EM challenge. Finally, a set of good-practices is prescribed for the community to benefit from the MDFF developments.

Ethical Use and Impact of Participatory Approaches to Research in Post-Disaster Environments: An Australian Bushfire Case Study

This paper presents a case study of Beyond Bushfires, a large, multisite, mixed method study of the psychosocial impacts of major bushfires in Victoria, Australia. A participatory approach was employed throughout the study which was led by a team of academic investigators in partnership with service providers and government representatives and used on-site visits and multiple methods of communication with communities across the state to inform decision-making throughout the study. The ethics and impacts of conducting and adapting the approach within a post-disaster context will be discussed in reference to theories and models of participatory health research. The challenges of balancing local interests with state-wide implications will also be explored in the description of the methods of engagement and the study processes and outcomes. Beyond Bushfires demonstrates the feasibility of incorporating participatory methods in large, post-disaster research studies and achieving rigorous findings and multilevel impacts, while recognising the potential for some of the empowering aspects of the participatory experience to be reduced by the scaled-up approach.

Vector-borne diseases

After a request from the European Commission, EFSA's Panel on Animal Health and Welfare summarised the main characteristics of 36 vector‐borne diseases (VBDs) in https://efsa.maps.arcgis.com/apps/PublicGallery/index.html?appid=dfbeac92aea944599ed1eb754aa5e6d1. The risk of introduction in the EU through movement of livestock or pets was assessed for each of the 36 VBDs individually, using a semiquantitative Method to INTegrate all relevant RISK aspects (MINTRISK model), which was further modified to a European scale into the http://www3.lei.wur.nl/mintrisk/ModelMgt.aspx. Only eight of the 36 VBD‐agents had an overall rate of introduction in the EU (being the combination of the rate of entry, vector transmission and establishment) which was estimated to be above 0.001 introductions per year. These were Crimean‐Congo haemorrhagic fever virus, bluetongue virus, West Nile virus, Schmallenberg virus, Hepatozoon canis, Leishmania infantum, Bunyamwera virus and Highlands J. virus. For these eight diseases, the annual extent of spread was assessed, assuming the implementation of available, authorised prevention and control measures in the EU. Further, the probability of overwintering was assessed, as well as the possible impact of the VBDs on public health, animal health and farm production. For the other 28 VBD‐agents for which the rate of introduction was estimated to be very low, no further assessments were made. Due to the uncertainty related to some parameters used for the risk assessment or the instable or unpredictability disease situation in some of the source regions, it is recommended to update the assessment when new information becomes available. Since this risk assessment was carried out for large regions in the EU for many VBD‐agents, it should be considered as a first screening. If a more detailed risk assessment for a specific VBD is wished for on a national or subnational level, the EFSA‐VBD‐RISK‐model is freely available for this purpose.

Epidemiological analyses on African swine fever in the Baltic countries and Poland

African swine fever virus (ASFV) has been notified in the Baltic countries and the eastern part of Poland from the beginning of 2014 up to now. In collaboration with the ASF‐affected Member States (MS), EFSA is updating the epidemiological analysis of ASF in the European Union which was carried out in 2015. For this purpose, the latest epidemiological and laboratory data were analysed in order to identify the spatial–temporal pattern of the epidemic and a risk factors facilitating its spread. Currently, the ASF outbreaks in wild boar in the Baltic countries and Poland can be defined as a small‐scale epidemic with a slow average spatial spread in wild boar subpopulations (approximately from 1 in Lithuania and Poland to 2 km/month in Estonia and Latvia). The number of positive samples in hunted wild boar peaks in winter which can be explained by human activity patterns (significant hunting activity over winter). The number of positive samples in wild boar found dead peaks in summer. This could be related to the epidemiology of the disease and/or the biology of wild boar; however, this needs further investigation. Virus prevalence in hunted wild boar is very low (0.04–3%), without any apparent trend over time. Apparent virus prevalence at country level in wild boar found dead in affected countries ranges from 60% to 86%, with the exception of Poland, where values between 0.5% and 1.42%, were observed. Since the beginning of the epidemic, the apparent antibody prevalence in hunted wild boar has always been lower than the apparent virus prevalence, indicating an unchanged epidemiological/immunological situation. The risk factor analysis shows an association between the number of settlements, human and domestic pigs population size or wild boar population density and the presence of ASF in wild boar for Estonia, Latvia and Lithuania.

Exploring attitudes and knowledge of climate change and sustainability in a dental practice: A feasibility study into resource management

Objective To understand the attitudes and behaviour of staff in dental practice towards adopting a reduce, reuse, recycle approach to resource management.Design A qualitative interview study.Setting The site for the study was a mixed NHS/private dental practice in North Devon.Subjects All disciplines from one dental practice.Methods (1) A practice scoping exercise - provided context and identified an interview sample. (2) Qualitative interviews with practice staff - explored knowledge and attitudes about sustainability and identified opportunities and limitations for the sustainable management of resources.Results The main issue raised by staff was the amount of waste generated. There was a strong desire to implement changes, but deep concerns were expressed about the impact of challenging current guidance on infection control.Conclusions Primary care dentistry provides both surgical and non-surgical care to more than half the UK population. Therefore, lessons learned from general dental practice can encourage positive change. More research is needed across dental practice in order to generalise these findings.

Predicting acute contact toxicity of pesticides in honeybees (Apis mellifera) through a k-nearest neighbor model

Ecological risk assessment of plant protection products (PPPs) requires an understanding of both the toxicity and the extent of exposure to assess risks for a range of taxa of ecological importance including target and non-target species. Non-target species such as honey bees (Apis mellifera), solitary bees and bumble bees are of utmost importance because of their vital ecological services as pollinators of wild plants and crops. To improve risk assessment of PPPs in bee species, computational models predicting the acute and chronic toxicity of a range of PPPs and contaminants can play a major role in providing structural and physico-chemical properties for the prioritisation of compounds of concern and future risk assessments. Over the last three decades, scientific advisory bodies and the research community have developed toxicological databases and quantitative structure-activity relationship (QSAR) models that are proving invaluable to predict toxicity using historical data and reduce animal testing. This paper describes the development and validation of a k-Nearest Neighbor (k-NN) model using in-house software for the prediction of acute contact toxicity of pesticides on honey bees. Acute contact toxicity data were collected from different sources for 256 pesticides, which were divided into training and test sets. The k-NN models were validated with good prediction, with an accuracy of 70% for all compounds and of 65% for highly toxic compounds, suggesting that they might reliably predict the toxicity of structurally diverse pesticides and could be used to screen and prioritise new pesticides.

A population-based study of primary care predictors of non-attendance for cervical screening

Objective: To identify and estimate the population impact of primary care service delivery factors that independently predict non-attendance for cervical screening.

Setting: Screening records of all eligible women aged 30 years and over and resident in the former Manchester Health Authority area were analysed (n=72,613).

Methods: Practice-level and GP-level explanatory variables, along with area-level covariates, were obtained and merged to the study data set. Logistic regression models were used to identify factors associated with having no recorded history of attending NHS cervical screening services. A multivariate model was created to identify independent predictors of non-attendance with comprehensive adjustment for women's age, area-level socio-demographic factors, and other primary care factors. Attributable fraction estimates were used to assess the population impact of the independent predictors.

Results: Large practice size (>4,000 patients), single-handed practice, South Asian male GP, part-time GP employment status, older age and birthplace overseas, and area-level measures of deprivation and transience independently predicted non-attendance. Women born overseas and registered at larger practices were especially unlikely to have ever attended. The combined population attributable fraction estimate for the independent predictors reflecting primary care service delivery was almost 40%, and that for all variables in the final model was over 70%.

Conclusions: Independent predictors of non-attendance reflecting general practice structure, workload and GP characteristics were identified. Although relative risks were modest, the collective population impact of these factors was considerable, which has implications for the implementation of informed targeting and the development of new screening services by Primary Care Trusts.

Health authority cervical screening recall policies and time since last smear: a retrospective cohort analysis in the north west of England

Objectives: To evaluate the impact of health authority cervical screening programmes upon the actual screening interval for women attending as a result of routine recall and to assess the impact of general practice recall policies on attendance for smears.

Setting: Nine health authorities constituting the Lancashire and Greater Manchester zones of the North West region of the National Health Service.

Methods: Information was obtained on the invitation and recall policies of each health authority. A retrospective analysis of information held on cervical screening databases ("Exeter" computer systems) was performed. The proportions of smears, classified by a screening interval of "unscheduled", "on-time", or "overdue", in the different health authority recall programmes were compared. General practices in one health authority (operating five-yearly recall) were contacted to determine their current practice screening policy.

Results: Women who were invited as part of a three-yearly recall programme were more likely to attend for smears at intervals of 3-5 years than those on a five-yearly recall programme (68% vs 47%). Those health authorities operating three-yearly recall that issued recall invitations to women more than four weeks before the date the smear was due had higher rates of "unscheduled" smears. In the one health authority (operating a five-yearly recall programme) in which we determined general practice screening policy, 62% of the general practitioners (GPs) were operating their own three-yearly recall policy; these GPs had a higher proportion of the women who attended for smears "on-time" (51%) than did those who relied on the heath authority five-yearly recall procedure (44%).

Conclusions: Despite the cervical screening programme being a national programme, there is scope at a local level for considerable variation in the interpretation of national guidance. This variation effects the extent to which programmes comply with the requirement to screen all women at an interval of 3-5 years.