Structured Online Modules and Near-Peer Teaching in Neuroanatomy Stimulate Active Learning and Can Have Beneficial Effects on Medical Students' Scores.

Introduction: As a solution to a decrease in curriculum time and the continuous growth of student-staff ratio, the Ghent University uses near-peer teaching (NPT) in neuroanatomy practical sessions. To improve learning outcomes, students involved in NPT created an online module. This study evaluated the added value of the online module and investigated tutees' learning experience with NPT. Materials and Methods: A cross-sectional study was conducted on second-year medical students who followed a model trajectory. Their completion rate of the online module and results of pre- and posttests on the practical session content, the spotter test, and the theoretical exam were evaluated. Additionally, all second-year medical students were invited to complete a questionnaire on NPT and practical experience. Results: A total of 253 second year students were included. Their completion rates of the online module were moderately correlated with the spotter exam results (r = 0.37, p < 0.001). Students who completed all pretests (96.44%) scored significantly better on the spotter exam (p < 0.001). Learners who completed all posttests (50.99%) scored significantly better on the spotter test (p < 0.001). Spotter tests and theoretical exam results were moderately correlated (r = 0.50, p < 0.001). Three-quarters of 352 second year students completed the questionnaire and fully agreed on all statements that assessed NPT and the practical sessions. Conclusion: An online neuroanatomy learning module stimulates active learning and can be helpful to improve students' spotter test and neuroanatomy exam scores. NPT is a valuable teaching resource and is generally well perceived in delivering high-quality education.

Screening algorithms for HBV, HCV, HIV and syphilis in an anatomical donation program.

BACKGROUND: Users of anatomical donors are at risk of exposure to bloodborne pathogens. This study evaluated screening algorithms for hepatitis B and C virus, human immunodeficiency virus and Treponema pallidum during donor allocation and assessed the impact of postmortem time on hemolysis and how hemolysis affects test results and donor discard rate. METHODS: From 2011 to 2018, demographic data of anatomical donors, time of postmortem blood sampling, presence of sample hemolysis, serological test results (negative; active infection; false reactive screening test; historic infection; inconclusive; technically impracticable) and the actual donor allocation were collected. RESULTS: Donors (n = 537) had a mean age of 77.53 ± 13.67 (24-103) year. Nine (1.68%) had laboratory test results indicative for active infection for hepatitis B (n = 1) and C virus (n = 2), human immunodeficiency virus (n = 5) and T. pallidum (n = 1). Negative screenings ranged from 74.67 to 97.58%, depending on the pathogen. According to the original screening algorithms, 479 (89.20%) donors should have been accepted. In practice, a donor acceptance rate of 91.20% was found. Analysis of potential donor allocation interpretation obstacles resulted in simplification of the in-house laboratory testing algorithms and addition of a nucleic acid test to increase the reliability for identification of active (acute) human immunodeficiency virus infection. Hemolysis was more common when sampling was performed more than 24 h after death (p < 0.001). Hemolytic samples more frequently showed a reactive or indeterminate human immunodeficiency virus test result (p < 0.001). Screening for human immunodeficiency virus and T. pallidum was technically more impracticable when hemolysis was present (p = 0.042 and p = 0.003, respectively). Donors with hemolytic blood samples were more often discarded (46.88%) compared to bodies with non-hemolytic samples (6.32%) (p < 0.001). CONCLUSIONS: Despite the implementation of donor screening algorithms, a significant number of bodies have an inconsistent allocation. New algorithms, to be evaluated in future research, were suggested. Early postmortem blood sampling is key as hemolysis can influence certain test results and donor allocation.

Electrostatic Intraperitoneal Aerosol Delivery of Nanoparticles: Proof of Concept and Preclinical Validation.

There is an increasing interest in intraperitoneal delivery of chemotherapy as an aerosol in patients with peritoneal metastasis. The currently used technology is hampered by inhomogenous drug delivery throughout the peritoneal cavity because of gravity, drag, and inertial impaction. Addition of an electrical force to aerosol particles, exerted by an electrostatic field, can improve spatial aerosol homogeneity and enhance tissue penetration. A computational fluid dynamics model shows that electrostatic precipitation (EP) results in a significantly improved aerosol distribution. Fluorescent nanoparticles (NPs) remain stable after nebulization in vitro, while EP significantly improves spatial homogeneity of NP distribution. Next, pressurized intraperitoneal chemotherapy with and without EP using NP albumin bound paclitaxel (Nab-PTX) in a novel rat model is examined. EP does not worsen the effects of CO2 insufflation and intraperitoneal Nab-PTX on mesothelial structural integrity or the severity of peritoneal inflammation. Importantly, EP significantly enhances tissue penetration of Nab-PTX in the anatomical regions not facing the nozzle of the nebulizer. Also, the addition of EP leads to more homogenous peritoneal tissue concentrations of Nab-PTX, in parallel with higher plasma concentrations. In conclusion, EP enhances spatial homogeneity and tissue uptake after intraperitoneal nebulization of anticancer NPs.

The brachial plexus - explaining its morphology and variability by a generic developmental model.

In classic anatomy teaching, the brachial plexus generally features as an enigmatic rote-learned structure, leaving the student with a feeling of complexity. The notion of complexity may increase in dissections, where plexuses significantly differing from the standard plexus model are readily found. This raises questions: what determines the existence and prevalence of variants and to what degree should they be considered anomalous? A model linking brachial plexus morphology and its variability to causative morphological parameters which would also standardize plexus description and teaching would be beneficial. The present study aims to provide such a model by analyzing the context of plexus development and applying this model in the analysis of plexus variability in anatomical specimens. Based on a thorough literature review, a generic developmental model was formulated and different factors of variability defined. In 56 plexuses, the proposed generic principles of plexus variability were found consistent with the variations encountered. Summarized, the modeled generic principles are as follows. Brachial plexus axon bundles grow out into an environment of chemical tracer paths in which constraints and obstacles are present: the geometry of the arm bud, cartilaginous bone precursors and vessels. The overall constancy of these factors generates a gross plexus outline, while the variability in these factors gives rise to typical plexus variations. The usefulness of the model derives from the fact that the variability of the main morphologically determining factors is not random but is the expression of the possibilities of the embryological substrate. Within the model, the major plexus morphological determinant is the segmental position of the subclavian artery, which is determined by the segment level of the intersegmental artery from which it develops. Normally, the subclavian artery develops from intersegmental artery i7. However, the subclavian artery can develop from inferior or superior segmental levels, from intersegmental artery i8 or i6, and possibly also from i9 or i5. Each of these arterial variants creates a typical, morphologically distinct, predictable plexus configuration. Superimposed on these basic plexus configurations, the underlying embryological substrate may develop further variability by integrating remnants of other intersegmental arteries into the arterial network. The resulting plexus configurations are further modified by local factors, e.g. the splitting of outgrowing axon bundles around vessels. A large split in the lateral cord around a large vein or veins crossing from lateral to medial, tangentially cranially over the subclavian artery was found in 54% of the 56 investigated BP and therefore might be added to plexus teaching. The distinct plexus morphologies associated with the subclavian artery segmental levels were further found associated with, among others, typical variations in the pectoral nerves and their ansas; these associations were also modeled. The presented models could allow brachial plexus rote learning to be replaced by a more insightful narrative of formative principles suitable for teaching. Clinically, improved understanding of the relationship between plexus variability and the local anatomical environment should be relevant to brachial plexus surgery and reconstruction.

Laparoscopic Liver Surgery Training Course on Thiel-Embalmed Human Cadavers: Program Evaluation, Trainer's Long-Term Feedback and Steps Forward.

OBJECTIVES: The purpose of this study was to evaluate the feedback of participants upon laparoscopic liver surgery (LLS) course on Thiel-embalmed human bodies. METHODS: From 2010 to 2017, ten LLS masterclasses have been organized by the Department of Hepatobiliary Surgery at Ghent University Hospital. A 23-question anonymous survey was electronically sent to 119 participants between November 2017 and January 2018, exploring their characteristics and asking for evaluation of the course. The obstacles for implementing LLS in their centers have been assessed. RESULTS: Sixty-four surgeons (53.8%) responded to the survey; 42 (65.6%) were employed at a university hospital; and 39 (60.9%) were in the first decade of their practice as a consultant surgeon. Forty-three (67.2%) surgeons reported an increased percentage of LLS cases afterward. Training on Thiel cadavers was considered superior (49.2%) to other training options including proctoring in the operating room (34.9%), virtual reality (6.3%), video training (4.8%) and practicing on pigs (4.8%). Obstacles identified contained inadequate training, patient's referral pattern, financial issues, lack of dedicated surgical team and time constrains. CONCLUSIONS: This survey revealed that a structured short-time program incorporating interactive discussion, live operations and hands-on training on human bodies under proctorship may enhance efficient training in laparoscopic liver surgery. In a step forward for upcoming courses, the importance of team building has to be addressed.

Systematic review of surgical training on reperfused human cadavers.

BACKGROUND: The role of reperfused human cadavers in surgical training has not been established. METHODS: Reports describing reperfused human cadaver models in terms of simulated surgeries, the use of tools to assess technical competency and skills transfer to patients, cadaver status and reperfusion techniques were included. RESULTS: Thirty-five reports were included. Most participants practised vascular (n = 27), flap (n = 6) and trauma (n = 4) procedures. Training progression was evaluated objectively in only two studies. In two publications, flap techniques were practised on cadavers and repeated successfully in patients. Eighteen studies employed whole bodies. Fresh and embalmed cadavers were both used in 17 publications. Most embalmed cadavers were formalin-fixed (n = 10), resulting in stiffness. Few trainings were offered on soft Thiel-embalmed cadavers (n = 5). Only arteries were reperfused in 20 studies, while in 13 publications, the arteries and veins were filled. Arteries and/or veins were mostly pressurized (n = 21) and arterial flow was generated in 14 studies. CONCLUSIONS: Various reperfused human cadaver models exist, enabling practise of mainly vascular procedures. Preservation method determines the level of simulation fidelity. Thorough evaluation of these models as surgical training tools and transfer effectiveness is still lacking.

Necroptotic cell death in anti-cancer therapy.

Necroptosis is one the best-characterized forms of regulated necrosis. Necroptosis is mediated by the kinase activities of receptor interacting protein kinase-1 and receptor interacting protein kinase-3, which eventually lead to the activation of mixed lineage kinase domain-like. Necroptosis is characterized by rapid permeabilization of the plasma membrane, which is associated with the release of the cell content and subsequent exposure of damage-associated molecular patterns (DAMPs) and cytokines/chemokines. This release underlies the immunogenic nature of necroptotic cancer cells and their ability to induce efficient anti-tumor immunity. Triggering necroptosis has become especially important in experimental cancer treatments as an alternative to triggering apoptosis because one of the hallmarks of cancer is the blockade or evasion of apoptosis. In this review, we discuss recent advances in necroptosis research and the functional consequences of necroptotic cancer cell death, with focus on its immunogenicity and its role in the activation of anti-tumor immunity. Next, we discuss the molecular mechanisms of phosphatidylserine exposure during necroptosis and its role in the recognition of necroptotic cells. We also highlight the complex role of the necroptotic pathway in tumor promotion and suppression and in metastasis. Future studies will show whether necroptosis is truly a better strategy to overcome apoptosis resistance and provide the insights needed for development of novel treatment strategies for cancer.

Release of urinary extracellular vesicles in prostate cancer is associated with altered urinary N-glycosylation profile.

AIM: Nowadays, extracellular vesicles are of great interest in prostate cancer (PCa) research. Asparagine (N)-linked glycosylation could play a significant role in the pathological mechanism of these vesicles. We investigated if prostatic protein N-glycosylation profiles were related to urinary vesicle-associated prostate-specific antigen (PSA) extractability and if this parameter showed diagnostic potential for PCa. METHODS: Urinary extracellular vesicles were visualised using transmission electron microscopy. Urinary extracellular vesicles extraction by means of n-butanol allowed determination of urinary vesicle-associated PSA extractability. Diagnostic value was assessed between benign prostate hyperplasia (BPH; n=122) and patients with PCa (n=85). Additionally, correlation with urine N-glycosylation was assessed. RESULTS: Urinary extracellular vesicles with a diameter of approximately 100 nm were more abundantly present in urine of patients with PCa versus patients with BPH resulting in a higher vesicle-associated PSA extraction ratio (p<0.001). Next, vesicle-associated PSA extraction ratio was correlated to biantennary core-fucosylation (p=0.003). Finally, vesicle-associated PSA extraction ratio proved beneficial in PCa diagnosis, next to serum PSA and the urinary glycosylation marker (p=0.021). CONCLUSIONS: The urinary vesicle-associated PSA extraction ratio is increased in PCa which is a direct result of the abundant presence of extracellular vesicles in urine of patients with PCa. The urinary vesicle-associated PSA extraction ratio was associated with changes in N-glycoforms and showed diagnostic potential. Further research is warranted to unravel the pathological link between N-glycosylation and extracellular vesicles in cancer, as well as to assess the prognostic value of this biomarker.

Lifelike Vascular Reperfusion of a Thiel-Embalmed Pig Model and Evaluation as a Surgical Training Tool.

BACKGROUND: Vascular reperfusion of Thiel cadavers can aid surgical and anatomical instruction. This study investigated whether ideal embalming circumstances provide lifelike vascular flow, enabling surgical practice and enhancing anatomical reality. METHODS: Pressure-controlled pump-driven administration of blue embalming solution was assessed directly postmortem in a pig model (n = 4). Investigation of subsequent pump-driven vascular injection of red paraffinum perliquidum (PP) included assessment of flow parameters, intracorporeal distribution, anatomical alterations, and feasibility for surgical training. The microscopic distribution of PP was analyzed in pump-embalmed pig and gravity-embalmed human small intestines. RESULTS: Embalming lasted 50-105 min, and maximum arterial pressure was 65 mm Hg. During embalming, the following consecutive alterations were observed: arterial filling, organ coloration, venous perfusion, and further tissue coloration during the next weeks. Most organs were adequately preserved. PP generated low arterial pressures (<30 mm Hg) and drained through the venous cannula. Generally, realistic reperfusion and preservation of original anatomy were observed, but leakage in the pleural, abdominal, and retroperitoneal cavities occurred, and computed tomography showed edematous spleen and liver. Reduction of arterial flow rates after venous drainage is a prerequisite to prevent anatomical deformation, allowing simulation of various surgeries. In pump-embalmed pig small intestines, PP flowed from artery to vein through the capillaries without extravasation. In contrast, arterioles were blocked in gravity-embalmed human tissues. CONCLUSIONS: In a pig model, immediate postmortem pressure-controlled pump embalming generates ideal circumstances for (micro)vascular reperfusion with PP, permitting lifelike anatomy instruction and surgical training.

Steroids affect gene expression, ciliary activity, glucose uptake, progesterone receptor expression and immunoreactive steroidogenic protein expression in equine oviduct explants in vitro.

The oviduct undergoes dramatic functional and morphological changes throughout the oestrous cycle of the mare. To unravel the effects of steroids on the morphology, functionality and gene expression of the equine oviduct, an in vitro oviduct explant culture system was stimulated with physiological concentrations of progesterone and 17ß-oestradiol. Four conditions were compared: unsupplemented preovulatory explants, preovulatory explants that were stimulated with postovulatory hormone concentrations, unsupplemented postovulatory explants and postovulatory explants that were stimulated with preovulatory hormone concentrations. The modulating effects of both steroids on oviduct explants were investigated and the following parameters examined: (1) ciliary activity, (2) glucose consumption and lactate production pattern, (3) ultrastructure, (4) mRNA expression of embryotrophic genes, (5) steroidogenic capacities of oviductal explants and (6) progesterone receptor expression. The present paper shows that the equine oviduct is an organ with potential steroidogenic capacities, which is highly responsive to local changes in progesterone and 17ß-oestradiol concentrations at the level of morphology, functionality and gene expression of the oviduct. These data provide a basis to study the importance of endocrine and paracrine signalling during early embryonic development in the horse.

Divergence between the Highly Virulent Zoonotic Pathogen Helicobacter heilmannii and Its Closest Relative, the Low-Virulence "Helicobacter ailurogastricus" sp. nov.

Helicobacter heilmannii naturally colonizes the stomachs of dogs and cats and has been associated with gastric disorders in humans. Nine feline Helicobacter strains, classified as H. heilmannii based on ureAB and 16S rRNA gene sequences, were divided into a highly virulent and a low-virulence group. The genomes of these strains were sequenced to investigate their phylogenetic relationships, to define their gene content and diversity, and to determine if the differences in pathogenicity were associated with the presence or absence of potential virulence genes. The capacities of these helicobacters to bind to the gastric mucosa were investigated as well. Our analyses revealed that the low-virulence strains do not belong to the species H. heilmannii but to a novel, closely related species for which we propose the name Helicobacter ailurogastricus. Several homologs of H. pylori virulence factors, such as IceA1, HrgA, and jhp0562-like glycosyltransferase, are present in H. heilmannii but absent in H. ailurogastricus. Both species contain a VacA-like autotransporter, for which the passenger domain is remarkably larger in H. ailurogastricus than in H. heilmannii. In addition, H. ailurogastricus shows clear differences in binding to the gastric mucosa compared to H. heilmannii. These findings highlight the low-virulence character of this novel Helicobacter species.

Correlation of clinical and physical-technical image quality in chest CT: a human cadaver study applied on iterative reconstruction.

BACKGROUND: The first aim of this study was to evaluate the correlation between clinical and physical-technical image quality applied to different strengths of iterative reconstruction in chest CT images using Thiel cadaver acquisitions and Catphan images. The second aim was to determine the potential dose reduction of iterative reconstruction compared to conventional filtered back projection based on different clinical and physical-technical image quality parameters. METHODS: Clinical image quality was assessed using three Thiel embalmed human cadavers. A Catphan phantom was used to assess physical-technical image quality parameters such as noise, contrast-detail and contrast-to-noise ratio (CNR). Both Catphan and chest Thiel CT images were acquired on a multislice CT scanner at 120 kVp and 0.9 pitch. Six different refmAs settings were applied (12, 30, 60, 90, 120 and 150refmAs) and each scan was reconstructed using filtered back projection (FBP) and iterative reconstruction (SAFIRE) algorithms (1,3 and 5 strengths) using a sharp kernel, resulting in 24 image series. Four radiologists assessed the clinical image quality, using a visual grading analysis (VGA) technique based on the European Quality Criteria for Chest CT. RESULTS: Correlation coefficients between clinical and physical-technical image quality varied from 0.88 to 0.92, depending on the selected physical-technical parameter. Depending on the strength of SAFIRE, the potential dose reduction based on noise, CNR and the inverse image quality figure (IQF(inv)) varied from 14.0 to 67.8%, 16.0 to 71.5% and 22.7 to 50.6% respectively. Potential dose reduction based on clinical image quality varied from 27 to 37.4%, depending on the strength of SAFIRE. CONCLUSION: Our results demonstrate that noise assessments in a uniform phantom overestimate the potential dose reduction for the SAFIRE IR algorithm. Since the IQF(inv) based dose reduction is quite consistent with the clinical based dose reduction, an optimised contrast-detail phantom could improve the use of contrast-detail analysis for image quality assessment in chest CT imaging. In conclusion, one should be cautious to evaluate the performance of CT equipment taking into account only physical-technical parameters as noise and CNR, as this might give an incomplete representation of the actual clinical image quality performance.

Analysis of metal artifact reduction tools for dental hardware in CT scans of the oral cavity: kVp, iterative reconstruction, dual-energy CT, metal artifact reduction software: does it make a difference?

INTRODUCTION: Metal artifacts may negatively affect radiologic assessment in the oral cavity. The aim of this study was to evaluate different metal artifact reduction techniques for metal artifacts induced by dental hardware in CT scans of the oral cavity. METHODS: Clinical image quality was assessed using a Thiel-embalmed cadaver. A Catphan phantom and a polymethylmethacrylate (PMMA) phantom were used to evaluate physical-technical image quality parameters such as artifact area, artifact index (AI), and contrast detail (IQFinv). Metal cylinders were inserted in each phantom to create metal artifacts. CT images of both phantoms and the Thiel-embalmed cadaver were acquired on a multislice CT scanner using 80, 100, 120, and 140 kVp; model-based iterative reconstruction (Veo); and synthesized monochromatic keV images with and without metal artifact reduction software (MARs). Four radiologists assessed the clinical image quality, using an image criteria score (ICS). RESULTS: Significant influence of increasing kVp and the use of Veo was found on clinical image quality (p = 0.007 and p = 0.014, respectively). Application of MARs resulted in a smaller artifact area (p < 0.05). However, MARs reconstructed images resulted in lower ICS. CONCLUSION: Of all investigated techniques, Veo shows to be most promising, with a significant improvement of both the clinical and physical-technical image quality without adversely affecting contrast detail. MARs reconstruction in CT images of the oral cavity to reduce dental hardware metallic artifacts is not sufficient and may even adversely influence the image quality.

Understanding Thiel embalming in pig kidneys to develop a new circulation model.

The quality of tissue preservation in Thiel embalmed bodies varies. Research on the administered embalming volume and its vascular distribution may elucidate one of the mechanisms of tissue preservation and allow for new applications of Thiel embalming. Vascular embalming with (group 1, n = 15) or without (group 2, n = 20) contrast agent was initiated in pig kidneys. The distribution of Thiel embalming solution in group 1 was visualized using computed tomography. The kidneys in both groups were then immersed in concentrated salt solutions to reduce their weight and volume. Afterwards, to mimic a lifelike circulation in the vessels, group 2 underwent pump-driven reperfusion for 120 minutes with either paraffinum perliquidum or diluted polyethylene glycol. The circulation was imaged with computed tomography. All of the kidneys were adequately preserved. The embalming solution spread diffusely in the kidney, but fluid accumulation was present. Subsequent immersion in concentrated salt solutions reduced weight (P < 0.01) and volume (P < 0.01). Reperfusion for 120 minutes was established in group 2. Paraffinum perliquidum filled both major vessels and renal tissue, whereas diluted polyethylene glycol spread widely in the kidney. There were no increases in weight (P = 0.26) and volume (P = 0.79); and pressure further decreased (P = 0.032) after more than 60 minutes of reperfusion with paraffinum perliquidum, whereas there were increases in weight (P = 0.005), volume (P = 0.032) and pressure (P < 0.0001) after reperfusion with diluted polyethylene glycol. Arterial embalming of kidneys results in successful preservation due to complete parenchymatous spreading. More research is needed to determine whether other factors affect embalming quality. Dehydration is an effective method to regain the organs' initial status. Prolonged vascular reperfusion with paraffinum perliquidum can be established in this model without increases in weight, volume and pressure.

Post-mortem Reperfusion of a Pig: a First Step to a New Surgical Training Model?

The purpose of this experimental study was to establish a short-term post-mortem circulation in a pig model using liquid paraffin. This study also investigated the quality of vascular perfusion in the peripheral tissues. This is the first step in the development of a new revascularized human surgical training model. This first experience was performed on the hind leg of a pig. Initial cannulation of the external iliac artery and vein was followed by connection of the arterial inflow to a heart-lung machine and using the venous outflow to flush post-mortem clots and blood. Subsequently, after connecting the venous outflow to the heart-lung machine, circulation was initiated. Circulation was established during 27 min, during which the flow was constantly 130 mL/min. A steady increase in inlet pressure was observed during the experiment, which finally reached a minimum value of 124 mmHg. Perfusion was interrupted early due to an uncontrollable fluid leak. Afterwards, the distal hind leg was incised showing an equal distribution of paraffin. A short-term revascularization was successfully re-established under excellent conditions. Although the results are promising, further experiments are necessary to eventually perform a wide range of surgical procedures on revascularized human cadavers.

Age-associated differential microRNA levels in human follicular fluid reveal pathways potentially determining fertility and success of in vitro fertilization.

Reproductive life span and fertility have been shown to depend on successful early folliculogenesis, which involves cell-to-cell communication and the concerted regulation of gene expression at both the oocyte and granulosa cell levels. Recently, micro RNAs (miRNAs) were identified as fine-tuners of gene expression. Here, we report that miRNAs can readily be detected within membrane-enclosed vesicles of human follicular fluid. MiRNA expression profiling of the follicular fluid of younger (<31 years) and older (>38 years) women revealed a set of four differentially expressed miRNAs. The predicted targets of these miRNAs are clearly enriched in genes involved in heparan-sulfate biosynthesis, extracellular matrix-receptor interaction, carbohydrate digestion and absorption, p53 signaling, and cytokine-cytokine-receptor interaction. Several of these pathways have been reported to be determinants of fertility, suggesting that this set of miRNAs and their respective targets should be evaluated in relation to reproductive aging and assisted reproduction.

Reliability and accuracy assessment of Radiation Therapy Oncology Group-endorsed guidelines for brachial plexus contouring.

PURPOSE: The goal of this work was to validate the Radiation Therapy Oncology Group (RTOG)-endorsed guidelines for brachial plexus (BP) contouring by determining the intra- and interobserver agreement. Accuracy of the delineation process was determined using anatomically validated imaging datasets as a gold standard. MATERIALS AND METHODS: Five observers delineated the right BP on three cadaver computed tomography (CT) datasets. To assess intraobserver variation, every observer repeated each delineation three times with a time interval of 2 weeks. The BP contours were divided into four regions for detailed analysis. Inter- and intraobserver variation was verified using the Computerized Environment for Radiation Research (CERR) software. Accuracy was measured using anatomically validated fused CT-magnetic resonance imaging (MRI) datasets by measuring the BP inclusion of the delineations. RESULTS: The overall kappa (κ) values were rather low (mean interobserver overall κ: 0.29, mean intraobserver overall κ: 0.45), indicating poor inter- and intraobserver reliability. In general, the κ coefficient decreased gradually from the medial to lateral BP regions. The total agreement volume (TAV) was much smaller than the union volume (UV) for all delineations, resulting in a low Jaccard index (JI; interobserver agreement 0-0.124; intraobserver agreement 0.004-0.636). The overall accuracy was poor, with an average total BP inclusion of 38%. Inclusions were insufficient for the most lateral regions (region 3: 21.5%; region 4: 12.6%). CONCLUSION: The inter- and intraobserver reliability of the RTOG-endorsed BP contouring guidelines was poor. BP inclusion worsened from the medial to lateral regions. Accuracy assessment of the contours showed an average BP inclusion of 38%. For the first time, this was assessed using the original anatomically validated BP volume. The RTOG-endorsed BP guidelines have insufficient accuracy and reliability, especially for the lateral head-and-neck regions.

Equine oviduct explant culture: a basic model to decipher embryo-maternal communication.

Equine embryos remain for 6 days in the oviduct and thus there is a need for an in vitro model to study embryo-oviductal interactions in the horse, since this subtle way of communication is very difficult to analyse in vivo. Until now, no equine oviduct explant culture model has been characterised both morphologically and functionally. Therefore, we established a culture system for equine oviduct explants that maintained epithelial morphology during 6 days of culture, as revealed by light microscopy and transmission electron microscopy. We demonstrated the presence of highly differentiated, tall columnar, pseudostratified epithelium with basal nuclei, numerous nucleoli, secretory granules and apical cilia, which is very similar to the in vivo situation. Both epithelium and stromal cells originating from the lamina propria are represented in the explants. Moreover, at least 98% of the cells remained membrane intact and fewer than 2% of the cells were apoptotic after 6 days of culture. Although dark-cell degeneration, which is a hypoxia-related type of cell death, was observed in the centre of the explants, quantitative real-time PCR failed to detect upregulation of the hypoxia-related marker genes HIF1A, VEGFA, uPA, GLUT1 and PAI1. Since the explants remained morphologically and functionally intact and since the system is easy to set up, it appears to be an excellent tool for proteome, transcriptome and miRNome analysis in order to unravel embryo-maternal interactions in the horse.