Plastic Surgery Outreach Clinics Expand Access to Cleft and Craniofacial Care in Mississippi.

ABSTRACT: Accessing treatment at ACPA (American Cleft Palate-Craniofacial Association)-approved centers is challenging for individuals in rural communities. This study aims to assess how pediatric plastic surgery outreach clinics impact access for patients with orofacial cleft and craniosynostosis in Mississippi. An isochrone map was used to determine mean travel times from Mississippi counties to the sole pediatric hospital and the only ACPA-approved team in the state. This analysis was done before and after the establishment of two outreach clinics to assess differences in travel times and cost of travel to specialized plastic surgery care. Two sample t-tests were used for analysis.The addition of outreach clinics in North and South Mississippi led to a significant reduction in mean travel times for patients with cleft and craniofacial diagnoses across the state's counties (1.81 hours vs 1.46 hours, P < 0.001). Noteworthy travel cost savings were observed after the introduction of outreach clinics when considering both the pandemic gas prices ($15.27 vs $9.80, P < 0.001) and post-pandemic prices ($36.52 vs $23.43, P < 0.001).The addition of outreach clinics in Mississippi has expanded access to specialized healthcare for patients with cleft and craniofacial differences resulting in reduced travel time and cost savings for these patients. Establishing specialty outreach clinics in other rural states across the United States may contribute significantly to reducing burden of care for patients with clefts and craniofacial differences. Future studies can further investigate whether the inclusion of outreach clinics improves follow-up rates and surgical outcomes for these patients.

Implementation of an Enhanced Recovery After Surgery Protocol for Cleft Palate Repair.

OBJECTIVE: This study examines an Enhanced Recovery After Surgery (ERAS) protocol for patients with cleft palate and hypothesizes that patients who followed the protocol would have decreased hospital length of stay and decreased narcotic usage than those who did not. DESIGN: Retrospective cohort study. SETTING: The study takes place at a single tertiary children's hospital. PATIENTS: All patients who underwent cleft palate repair during a 10-year period (n = 242). INTERVENTIONS: All patients underwent cleft palate repair with the most recent cohort following a new ERAS protocol. MAIN OUTCOME MEASURES: Primary outcomes included hospital length of stay and narcotic usage in the first 24 hours after surgery. RESULTS: Use of local bupivacaine during surgery was associated with decreased initial 24-hour morphine equivalent usage: 2.25 vs 3.38 mg morphine equivalent (MME) (P < 0.01), and a decreased hospital length of stay: 1.71 days vs 2.27 days (P < 0.01). The highest 24-hour morphine equivalent a patient consumed prior to the ERAS protocol implementation was 24.53 MME, compared with 6.3 MME after implementation. Utilization of the ERAS protocol was found to be associated with a decreased hospital length of stay: 1.67 vs 2.18 days (P < 0.01). CONCLUSIONS: Use of the proposed ERAS protocol may lead to lower narcotic usage and decreased length of stay.

Longitudinal Speech and Fistula Outcomes Following Primary Cleft Palate Repair at a Single Institution.

INTRODUCTION: Fistula formation and velopharyngeal insufficiency (VPI) are complications of cleft palate repair that often require surgical correction. The goal of the present study was to examine a single institution's experience with cleft palate repair with respect to fistula formation and need for surgery to correct velopharyngeal dysfunction. METHODS: Institutional review board approval was obtained. Patient demographics and operative details over a 10-year period were collected. Primary outcomes measured were development of fistula and need for surgery to correct VPI. Chi-square tests and independent t tests were utilized to determine significance (0.05). RESULTS: Following exclusion of patients without enough information for analysis, 242 patients were included in the study. Fistulas were reported in 21.5% of patients, and surgery to correct velopharyngeal dysfunction was needed in 10.7% of patients. Two-stage palate repair was associated with need for surgery to correct VPI (P = 0.014). Furlow palatoplasty was associated with decreased rate of fistula formation (P = 0.002) and decreased need for surgery to correct VPI (P = 0.014). CONCLUSION: This study reiterates much of the literature regarding differing cleft palate repair techniques. A 2-stage palate repair is often touted as having less growth restriction, but the present study suggests this may yield an increased need for surgery to correct VPI. Prior studies of Furlow palatoplasty have demonstrated an association with higher rates of fistula formation. The present study demonstrated a decreased rate of fistula formation with the Furlow technique, which may be due to the use of the Children's Hospital of Philadelphia modification. This study suggests clinically superior outcomes of the Furlow palatoplasty over other techniques.

Mandibular Distraction in Patients With Pierre Robin Sequence: A Multisurgeon Experience.

OBJECTIVE: Mandibular distraction osteogenesis (MDO) is rapidly becoming a standard of care for management of patients with severe Pierre Robin sequence. The tongue is brought forward to alleviate airway obstruction. This study will look at an institutional, multisurgeon experience with MDO over 10 years. DESIGN: A retrospective chart review was conducted. SETTING: All patients who underwent MDO at the authors' institution from 2012 to 2022 were included. Three craniofacial surgeons performed all interventions. PATIENTS: Demographics, preoperative and postoperative respiratory and feeding status, and distraction data were collected for 27 patients meeting inclusion criteria. MAIN OUTCOME MEASURES: Primary outcomes were avoidance of a gastrostomy tube, avoidance of a tracheostomy, discharge from hospital on room air, and complications. A significance value of 0.05 was utilized. RESULTS: The average age at MDO was 135 days, mean activation phase was 13.6 days, mean distraction length was 14.9 mm, and mean consolidation phase was 64.2 days. A longer activation phase was associated with discharge with a gastrostomy tube and a shorter activation phase was associated with discharge on full oral feeds. The ability to discharge on room air was associated with a shorter latency phase, shorter activation phase, and decreased distance of distraction. CONCLUSIONS: The goal of MDO is to achieve full oral feeds with no respiratory support. Several different latency periods were used in this study, and a short latency period was demonstrated to be safe.

Patients Requiring Multiple Surgeries for Velopharyngeal Insufficiency: Findings From a 10-Year Retrospective Review.

This study analyzed patients undergoing multiple surgeries for velopharyngeal insufficiency (VPI) and reviewed their preoperative evaluations and techniques selected for subsequent surgeries. A retrospective chart review was performed including patients having undergone multiple surgeries for VPI at the authors' institution between 2012 and 2022. All patients were evaluated and managed at the author's institution under the direction of 4 senior surgeons. The objective of this study was to provide insight into preoperative evaluation, surgical technique selection, and other factors that may contribute to patients who require multiple VPI surgeries. Of 71 patients having undergone surgery for VPI, 8 required at least 1 additional operation for persistent VPI following the initial intervention. Six patients who initially underwent a superiorly based posterior pharyngeal flap (PPF) required additional surgery, and for those patients' subsequent operations, 5 different techniques were used throughout their treatment. Of the remaining 2 patients who had multiple VPI surgeries, 1 initially received autologous fat transfer and 1 initially underwent a furlow palatoplasty. Finally, 0 patients that initially underwent buccal flaps or collagen injection required further unplanned surgical intervention. This study demonstrates the importance of selecting an appropriate surgical approach when operating on patients following a failed VPI surgery. The algorithm developed from these findings emphasizes the importance of properly identifying the anatomical deficiency resulting from the failed intervention. A review of the advantages of nasopharyngoscopy as a preoperative evaluative technique of velopharyngeal form and function when compared to lateral barium video fluoroscopy was also included.

Population growth of two limno-terrestrial Antarctic microinvertebrates in different aqueous soil media.

Terrestrial microinvertebrates provide important carbon and nutrient cycling roles in soil environments, particularly in Antarctica where larger macroinvertebrates are absent. The environmental preferences and ecology of rotifers and tardigrades in terrestrial environments, including in Antarctica, are not as well understood as their temperate aquatic counterparts. Developing laboratory cultures is critical to provide adequate numbers of individuals for controlled laboratory experimentation. In this study, we explore aspects of optimising laboratory culturing for two terrestrially sourced Antarctic microinvertebrates, a rotifer (Habrotrocha sp.) and a tardigrade (Acutuncus antarcticus). We tested a soil elutriate and a balanced salt solution (BSS) to determine their suitability as culturing media. Substantial population growth of rotifers and tardigrades was observed in both media, with mean rotifer population size increasing from 5 to 448 ± 95 (soil elutriate) and 274 ± 78 (BSS) individuals over 60 days and mean tardigrade population size increasing from 5 to 187 ± 65 (soil elutriate) and 138 ± 37 (BSS) over 160 days. We also tested for optimal dilution of soil elutriate in rotifer cultures, with 20-80% dilutions producing the largest population growth with the least variation in the 40% dilution after 36 days. Culturing methods developed in this study are recommended for use with Antarctica microinvertebrates and may be suitable for similar limno-terrestrial microinvertebrates from other regions.

Dose-dependent changes in cardiac function, strain and remodelling in a preclinical model of heart base irradiation.

BACKGROUND AND PURPOSE: Radiation induced cardiotoxicity (RICT) is as an important sequela of radiotherapy to the thorax for patients. In this study, we aim to investigate the dose and fractionation response of RICT. We propose global longitudinal strain (GLS) as an early indicator of RICT and investigate myocardial deformation following irradiation. METHODS: RICT was investigated in female C57BL/6J mice in which the base of the heart was irradiated under image-guidance using a small animal radiation research platform (SARRP). Mice were randomly assigned to a treatment group: single-fraction dose of 16 Gy or 20 Gy, 3 consecutive fractions of 8.66 Gy, or sham irradiation; biological effective doses (BED) used were 101.3 Gy, 153.3 Gy and 101.3 Gy respectively. Longitudinal transthoracic echocardiography (TTE) was performed from baseline up to 50 weeks post-irradiation to detect structural and functional effects. RESULTS: Irradiation of the heart base leads to BED-dependent changes in systolic and diastolic function 50 weeks post-irradiation. GLS showed significant decreases in a BED-dependent manner for all irradiated animals, as early as 10 weeks after irradiation. Early changes in GLS indicate late changes in cardiac function. BED-independent increases were observed in the left ventricle (LV) mass and volume and myocardial fibrosis. CONCLUSIONS: Functional features of RICT displayed a BED dependence in this study. GLS showed an early change at 10 weeks post-irradiation. Cardiac remodelling was observed as increases in mass and volume of the LV, further supporting our hypothesis that dose to the base of the heart drives the global heart toxicity.

Characterisation of quantitative imaging biomarkers for inflammatory and fibrotic radiation-induced lung injuries using preclinical radiomics.

BACKGROUND AND PURPOSE: Radiomics is a rapidly evolving area of research that uses medical images to develop prognostic and predictive imaging biomarkers. In this study, we aimed to identify radiomics features correlated with longitudinal biomarkers in preclinical models of acute inflammatory and late fibrotic phenotypes following irradiation. MATERIALS AND METHODS: Female C3H/HeN and C57BL6 mice were irradiated with 20 Gy targeting the upper lobe of the right lung under cone-beam computed tomography (CBCT) image-guidance. Blood samples and lung tissue were collected at baseline, weeks 1, 10 & 30 to assess changes in serum cytokines and histological biomarkers. The right lung was segmented on longitudinal CBCT scans using ITK-SNAP. Unfiltered and filtered (wavelet) radiomics features (n = 842) were extracted using PyRadiomics. Longitudinal changes were assessed by delta analysis and principal component analysis (PCA) was used to remove redundancy and identify clustering. Prediction of acute (week 1) and late responses (weeks 20 & 30) was performed through deep learning using the Random Forest Classifier (RFC) model. RESULTS: Radiomics features were identified that correlated with inflammatory and fibrotic phenotypes. Predictive features for fibrosis were detected from PCA at 10 weeks yet overt tissue density was not detectable until 30 weeks. RFC prediction models trained on 5 features were created for inflammation (AUC 0.88), early-detection of fibrosis (AUC 0.79) and established fibrosis (AUC 0.96). CONCLUSIONS: This study demonstrates the application of deep learning radiomics to establish predictive models of acute and late lung injury. This approach supports the wider application of radiomics as a non-invasive tool for detection of radiation-induced lung complications.

Perioperative Management of Obstructive Sleep Apnea in Patients With Syndromic Craniosynostosis Undergoing LeFort III Osteotomy With Distraction: A Case Series.

Study Design: Retrospective observational study. Objective: The purpose of this publication is to address the absence of literature detailing respiratory management in patients with syndromic craniosynostosis and obstructive sleep apnea during the immediate postoperative interval following LeFort III advancement with placement of distraction hardware but prior to sufficient midface advancement. Methods: After IRB approval, the investigators retrospectively selected candidates for inclusion in this case series. The sample was composed of four patients ranging from 10 to 19 years of age undergoing LeFort III midface advancement during a one-year span at a single tertiary care center. All operations were performed by a single surgeon. Three of the selected patients suffered significant obstructive sleep apnea necessitating the operation, as determined by polysomnography. One patient experienced persistent apnea postoperatively requiring prolonged ICU level care. Results: Three of the four patients had severe OSA diagnosed by polysomnography with a median AHI of 28.3. Two of the three patients with preoperative OSA experienced no untoward respiratory compromise in the immediate postoperative period; one required nightly oxygen tent and the other required no supplemental oxygen. Patient 1 experienced significant postoperative respiratory distress with nightly apneic episodes and desaturations requiring supplemental oxygen and frequent stimulation. Conclusions: The present study suggests that early involvement of sleep medicine and management of patient expectations is vital. Extremely close postoperative monitoring in the ICU is necessary. Future studies are needed to protocolize perioperative management of obstructive sleep apnea in patients undergoing LeFort III osteotomy prior to initiation and completion of midface advancement.

Plastic Surgery: Beware the Candle Burning at Both Ends.

Background: Plastic surgery dates back to 800 BC, where forehead flaps were used to reconstruct noses in India. Today, it is one of the most romanticized fields in medicine. Due to the influence of social media, there has never been a larger spotlight. Ironically, this spotlight brings a narrowed perception of the scope of plastic surgery. This study aimed to assess the scope through the eyes of the average American to identify gaps in knowledge to better represent the field. Methods: A series of questions were developed under survey methodologists and administered by Qualtrics. Responses were gathered, and data were analyzed to assess the public's knowledge of plastic surgery's scope. Results: Two thousand five hundred responses were obtained, balanced across demographics similar to that of the United States. The US population has a poor understanding of the scope of plastic surgery and how to obtain board certification. Conclusions: This survey demonstrates a gap in awareness of plastic surgery as a field and the scope outside aesthetic procedures dramatized by the media. There remains no clear understanding of the qualifications of plastic surgeons or the provider makeup of the field of cosmetic surgery. Subspecialties proved to be overlooked, and knowledge of board certification was sparse. Further effort is needed to educate both the public and patients of the scope of plastic surgery, so that they might seek and gain access to appropriate treatment in the most efficient manner to optimize outcomes regarding the form and function of the body.

A Digital Diabetes Storytelling Intervention for the Hmong Community: A Pilot Study.

Hmong-Americans experience higher rates of diabetes and poorer diabetes-related health outcomes than their White peers. Traditional methods of diabetes education do not reach Hmong patients effectively due to known socioeconomic and literacy barriers. The purpose of this study is to examine the acceptability of a culturally informed diabetes self-management education video tool, using digital storytelling that was created using a community-engaged approach, administered in a single academic clinic that sees a large percentage of Hmong patients. The video tool was successful in the areas of acceptability, story transformation, and story identification; 96% of participants stated that the video felt like something from their community, 88% stated that they could identify with the story, 79% stated that they wanted to know what happened next, and 70% of participants reported that they were motivated to do something different after watching. New methods to improve diabetes education and improve health outcomes in Hmong communities are needed. Culturally informed digital storytelling is one tool, which may be used to improve diabetes health outcomes in this population.

Subdermal Plexus Density as It Relates to Obesity and Wound Complications in Patients Undergoing Reduction Mammaplasty.

Background: Reduction mammaplasty is one of the most common reconstructive procedures performed in plastic surgery. Multiple comorbidities play a role in postoperative wound healing complications; however, there are insufficient data on the subdermal plexus (SDP) as it relates to these comorbidities. The purpose of this study is to evaluate the relationship between body mass index (BMI) and SDP of the superficial breast tissues and examine the association between SDP and postoperative complications. Methods: After Institutional Review Board approval, screening, and informed consent, patients undergoing reduction mammaplasty were selected. Tissue to be discarded was sent to pathology for analysis of immunohistochemistry directed against endothelial cells to determine the density of the SDP. Patients with BMI <35 and ≥35 kg/m2 were compared. Statistical analysis, including 2-tailed t test and Pearson correlation, was conducted. Results: A significant difference in SDP density (standard deviation) was identified between patients with a BMI ≥35 versus <35 kg/m2 (2.65 capillaries/mm2 ± 1.8 vs 1.56 capillaries/mm2 ± 1.2; P = .033). Patients with no historical use of tobacco versus those who used tobacco showed a significantly increased SDP (2.11 capillaries/mm2 ± 1.6 vs 1.20 capillaries/mm2 ± 0.5; P = .009). A significant relationship between postoperative infection (1.00 capillaries/mm2 ± 1.1; P = .041) and hematoma/seroma (0.788 capillaries/mm2 ± 0.1; P = .003) was identified. No significant relationship was found between SDP and delayed wound healing, nipple-areolar complex complications, fat/flap necrosis, or symptomatic scar occurrence. Conclusions: There is a statistically significant increase in SDP seen with increasing BMI, which does not explain the higher rate of wound healing complications after reduction mammaplasty typically seen in the higher BMI patient population. The association between BMI and complications after reduction mammaplasty remains unclear.

Assessment of Variabilities in Lung-Contouring Methods on CBCT Preclinical Radiomics Outputs.

Radiomics image analysis has the potential to uncover disease characteristics for the development of predictive signatures and personalised radiotherapy treatment. Inter-observer and inter-software delineation variabilities are known to have downstream effects on radiomics features, reducing the reliability of the analysis. The purpose of this study was to investigate the impact of these variabilities on radiomics outputs from preclinical cone-beam computed tomography (CBCT) scans. Inter-observer variabilities were assessed using manual and semi-automated contours of mouse lungs (n = 16). Inter-software variabilities were determined between two tools (3D Slicer and ITK-SNAP). The contours were compared using Dice similarity coefficient (DSC) scores and the 95th percentile of the Hausdorff distance (HD95p) metrics. The good reliability of the radiomics outputs was defined using intraclass correlation coefficients (ICC) and their 95% confidence intervals. The median DSC scores were high (0.82-0.94), and the HD95p metrics were within the submillimetre range for all comparisons. the shape and NGTDM features were impacted the most. Manual contours had the most reliable features (73%), followed by semi-automated (66%) and inter-software (51%) variabilities. From a total of 842 features, 314 robust features overlapped across all contouring methodologies. In addition, our results have a 70% overlap with features identified from clinical inter-observer studies.

Burnout Among Psychiatry Residents and One Program's Approach to Creating a Culture of Wellness.

Psychiatry residency training includes unique characteristics that can predispose trainees to burnout, including vicarious traumatization, prevalence of patient suicide and violence in the workplace, and social stigma surrounding mental health. For the purposes of this article, the authors examine these contributing factors and address how psychiatry residency training programs, specifically the Kaiser Permanente Oakland program, are responding to these unique challenges with wellness initiatives. Initiatives to promote wellness at Kaiser Permanente Oakland include a resident and faculty-led wellness committee, work-hour limits, reasonable call schedules, a robust mentorship program, funded social and networking events programs, and comprehensive mental health services.

Development and optimisation of a preclinical cone beam computed tomography-based radiomics workflow for radiation oncology research.

Background and purpose: Radiomics features derived from medical images have the potential to act as imaging biomarkers to improve diagnosis and predict treatment response in oncology. However, the complex relationships between radiomics features and the biological characteristics of tumours are yet to be fully determined. In this study, we developed a preclinical cone beam computed tomography (CBCT) radiomics workflow with the aim to use in vivo models to further develop radiomics signatures. Materials and methods: CBCT scans of a mouse phantom were acquired using onboard imaging from a small animal radiotherapy research platform (SARRP, Xstrahl). The repeatability and reproducibility of radiomics outputs were compared across different imaging protocols, segmentation sizes, pre-processing parameters and materials. Robust features were identified and used to compare scans of two xenograft mouse tumour models (A549 and H460). Results: Changes to the radiomics workflow significantly impact feature robustness. Preclinical CBCT radiomics analysis is feasible with 119 stable features identified from scans imaged at 60 kV, 25 bin width and 0.26 mm slice thickness. Large variation in segmentation volumes reduced the number of reliable radiomics features for analysis. Standardization in imaging and analysis parameters is essential in preclinical radiomics analysis to improve accuracy of outputs, leading to more consistent and reproducible findings. Conclusions: We present the first optimised workflow for preclinical CBCT radiomics to identify imaging biomarkers. Preclinical radiomics has the potential to maximise the quantity of data captured in in vivo experiments and could provide key information supporting the wider application of radiomics.

Bipedicled Palatoplasty for Closure of Wide Veau Class II Anterior Palatal Defect: A Case Series.

Background: Wide palatal defects remain a challenge to the plastic surgeon. The authors present a new method for closure of a wide Veau class II cleft palate in which anterior palatal closure was achieved by use of a bipedicled mucoperiosteal anterior palatal flap. Methods: Two patients with wide Veau class II cleft palatal defects underwent palatoplasty with difficulty in closing the anterior palate. A novel technique was employed for tension-free closure. Results: A tension-free closure in the midline was achieved with a bipedicled mucoperiosteal anterior palatal flap. Conclusions: This novel technique can assist with closure of the anterior-most portion of hard palatal defects.

High Sensitivity of the Antarctic Rotifer Adineta editae to Metals and Ecological Relevance in Contaminated Site Risk Assessments.

Anthropogenic activities in Antarctica have led to contamination of terrestrial sites, and soils in ice-free areas have elevated concentrations of metals, particularly around current and historic research stations. Effective management of Antarctic contaminated sites depends on the assessment of risks to a representative range of native terrestrial species. Bdelloid rotifers are an abundant and biodiverse component of Antarctic limnoterrestrial communities and play a key role in nutrient cycling in Antarctic ecosystems. The present study investigates the toxicity of five metals (cadmium, copper, nickel, lead, and zinc) to the endemic bdelloid rotifer Adineta editae, both singly and in metal mixtures. Based on the concentrations tested, zinc was the most toxic metal to survival with a 7-day median lethal concentration (LC50) of 344 µg Zn/L, followed by cadmium with a 7-day LC50 of 1542 µg Cd/L. Rotifers showed high sensitivity using cryptobiosis (chemobiosis) as a sublethal behavioral endpoint. Chemobiosis was triggered in A. editae at low metal concentrations (e.g., 6 µg/L Pb) and is likely a protective mechanism and survival strategy to minimize exposure to stressful conditions. Lead and copper were most toxic to rotifer behavior, with 4-day median effect concentrations (EC50s) of 18 and 27 µg/L, respectively, followed by zinc and cadmium (4-day EC50 values of 52 and 245 µg/L, respectively). The response of rotifers to the metal mixtures was antagonistic, with less toxicity observed than was predicted by the model developed from the single-metal exposure data. The present study provides evidence that this bdelloid rotifer represents a relatively sensitive microinvertebrate species to metals and is recommended for use in contaminant risk assessments in Antarctica. Environ Toxicol Chem 2023;42:1409-1419. © 2023 SETAC.

A Review on Lumps, Bumps, and Birthmarks: When and Why to Refer.

Skin lesions of the face, trunk, and extremities are commonly seen in the pediatric population. Although most of these lesions are benign, they can be locally destructive or interfere with normal development. Recognition and diagnosis of these lesions allow for timely workup and referral; treatment, if needed; and facilitation of parental discussions. The purpose of this article is to review common pediatric skin and soft-tissue lesions-or "lumps, bumps, and birthmarks"-to assist with diagnosis, workup, and guidelines for referral to pediatric plastic surgery. [Pediatr Ann. 2023;52(1):e23-e30.].

Assessing risks from fuel contamination in Antarctica: Dynamics of diesel ageing in soil and toxicity to an endemic nematode.

Fuel spills are a major source of contamination in terrestrial environments in Antarctica. Little is known of the effects of hydrocarbon contaminants in fuels on Antarctic terrestrial biota, and how these change as fuel ages within soil. In this study we investigate the sensitivity of juveniles of the endemic Antarctic nematode Plectus murrayi to diesel-spiked soil. Toxicity tests were conducted on soil elutriates, and changes in concentrations of hydrocarbons, polar compounds and PAHs were assessed as the spiked soil was artificially aged at 3 °C over a 45-week period, representing multiple summer seasons of fuel degradation. Nematodes were most sensitive to elutriates made from freshly spiked soils (LC50 419 µg/L TPH and 156 µg/L TPH-SG), with a subsequent decline in toxicity observed in the first 6 weeks of laboratory ageing (LC50 2945 µg/L TPH and 694 µg/L TPH-SG). Effects were still evident up to 45 weeks (lowest observed effect concentration 2123 µg/L TPH) despite hydrocarbons being depleted from soils with ageing (84 % loss) and elutriates becoming dominated by polar metabolites (95 % polar). Nematode sensitivity throughout the ageing period showed evidence of a relationship between LC50 and the proportions of the lighter carbon range fraction of TPH in elutriates, the F2 fraction (C10-14). This study is the first to estimate the sensitivity of Antarctic terrestrial fauna to diesel and provides novel data on the dynamics of fuel chemistry under Antarctic conditions and how this influences toxicity. Findings contribute to predicting ecological risk at existing diesel fuel spill sites in Antarctica, to the derivation of site-specific remediation targets, and to environmental guidelines to assess ecosystem health.

Feasibility and guidelines for the use of an injectable fiducial marker (BioXmark ®) to improve target delineation in preclinical radiotherapy studies using mouse models.

BACKGROUND: Preclinical models of radiotherapy (RT) response are vital for the continued success and evolution of RT in the treatment of cancer. The irradiation of tissues in mouse models necessitates high levels of precision and accuracy to recapitulate clinical exposures and limit adverse effects on animal welfare. This requirement has been met by technological advances in preclinical RT platforms established over the past decade. Small animal RT systems use onboard computed tomography (CT) imaging to delineate target volumes and have significantly refined radiobiology experiments with major 3Rs impacts. However, the CT imaging is limited by the differential attenuation of tissues resulting in poor contrast in soft tissues. Clinically, radio-opaque fiducial markers (FMs) are used to establish anatomical reference points during treatment planning to ensure accuracy beam targeting, this approach is yet to translate back preclinical models. METHODS: We report on the use of a novel liquid FM BioXmark ® developed by Nanovi A/S (Kongens Lyngby, Denmark) that can be used to improve the visualisation of soft tissue targets during beam targeting and minimise dose to surrounding organs at risk. We present descriptive protocols and methods for the use of BioXmark ® in experimental male and female C57BL/6J mouse models. RESULTS: These guidelines outline the optimum needle size for uptake (18-gauge) and injection (25- or 26-gauge) of BioXmark ® for use in mouse models along with recommended injection volumes (10-20 µl) for visualisation on preclinical cone beam CT (CBCT) scans. Injection techniques include subcutaneous, intraperitoneal, intra-tumoral and prostate injections. CONCLUSIONS: The use of BioXmark ® can help to standardise targeting methods, improve alignment in preclinical image-guided RT and significantly improve the welfare of experimental animals with the reduction of normal tissue exposure to RT.