Systematic update to the mammalian relative potency estimate database and development of best estimate toxic equivalency factors for dioxin-like compounds

The World Health Organization (WHO) assesses potential health risks of dioxin-like compounds using Toxic Equivalency Factors (TEFs). This study systematically updated the relative potency (REP) database underlying the 2005 WHO TEFs and applied advanced methods for quantitative integration of study quality and dose-response. Data obtained from fifty-one publications more than doubled the size of the previous REP database (∼1300 datasets). REP quality and relevance for these data was assessed via application of a consensus-based weighting framework. Using Bayesian dose-response modeling, available data were modeled to produce standardized dose/concentration-response Hill curves. Study quality and REP data were synthesized via Bayesian meta-analysis to integrate dose/concentration-response data, author-calculated REPs and benchmark ratios. The output is a prediction of the most likely relationship between each congener and its reference as model-predicted TEF uncertainty distributions, or the 'best estimate TEF' (BE-TEF). The resulting weighted BE-TEFs were similar to the 2005 TEFs, though provide more information to inform selection of TEF values as well as to provide risk assessors and managers with information needed to quantitatively characterize uncertainty around TEF values. Collectively, these efforts produce an updated REP database and an objective, reproducible approach to support development of TEF values based on all available data.

Review of standard paediatric neuroradiology MRI protocols from 12 UK tertiary paediatric hospitals: is there much variation between centres?

AIM

To investigate how magnetic resonance imaging (MRI) examinations are protocolled in tertiary paediatric neuroradiology centres around the UK for some of the more common presentations encountered in paediatric neuroradiology, and to identify any variations of note.

MATERIALS AND METHODS

All 19 UK tertiary paediatric neuroradiology centres registered with the British Society of Neuroradiologists-Paediatric Group were contacted and asked if they could provide a copy of their standard MRI protocols. Twelve responded (63%) and 10 of the more common presentations were selected and the standard acquired sequences obtained at each participating centre were compared. Where available the collated protocols were also compared against current published guidance.

RESULTS

The basic sequences carried out by centres around the UK are similar; however, there are lots of variations overall. The only standardised protocol currently being implemented nationally in paediatric imaging is that for brain tumours. Otherwise, chosen protocols are generally dependent on the preferences and technical capabilities of individual centres. Suggested published protocols also exist for non-accidental injury (NAI), multiple sclerosis, epilepsy, and head and neck imaging.

CONCLUSIONS

The differences in MRI protocolling depend in part on technical capabilities and in part on the experience and preferences of the paediatric neuroradiologists at each centre. For most presentations, there is no consensus as to what constitutes the perfect protocol. The present results will be useful for specialist centres who may wish to review their current protocols, and for more generalist centres to use as a reference to guide their MRI protocolling.

Eating disorders are associated with increased risk of fall injury and fracture in Swedish men and women

In this retrospective cohort study, men and women with eating disorders (n = 8867) had higher risk of injurious falls and hip fractures than age, sex, and county-matched controls (n = 88670).

INTRODUCTION

Eating disorders have been associated with decreased bone mineral density and increased fracture risk, but the association with fall injuries without fracture has not previously been investigated. Furthermore, fracture risk in men with eating disorders has been insufficiently studied.

METHODS

In the present study, 8867 patients (9.4% men) with a diagnosed eating disorders and 88670 age-, sex-, and county-matched controls were investigated.

RESULTS

The mean (standard deviation) age of the patients and controls was 41.6 (13.7) years and the follow-up time 9.6 (5.2, 14.4) years (median, interquartile range) for patients and 10.1 (5.5, 14.2) years for controls. The proportions of injurious falls without fracture (17.3% vs. 9.0%) and of hip fracture (1.6% vs. 0.7%) were substantially greater in patients with an eating disorder than in their corresponding population controls. In an unadjusted Cox proportional hazards model, individuals with an eating disorder had a higher risk of injurious falls without fracture (Hazard ratio (HR) 95% confidence interval (CI): 2.07 (1.96-2.18), and hip fracture (HR 2.30 (1.92-2.75)) than the risk observed in the controls. The HR for any investigated outcome associated with an eating disorder did not differ by sex or age (interaction term p > 0.10). The risk of injurious falls without fracture and hip fracture was increased in both women (HR 2.07 (1.95-2.19) and HR 2.41 (1.98-2.93), respectively) and men (HR 2.09 (1.76-2.49) and HR 1.84(1.12-3.02), respectively), with an eating disorder.

CONCLUSION

The risk of injurious falls without fracture and of hip fracture is increased in both women and men with eating disorders, indicating measures to prevent both falls and fractures are important in these patients, regardless of age and sex.

An analysis of qualitative responses from a UK survey of the psychosocial wellbeing of people with skin conditions and their experiences of accessing psychological support

BACKGROUND

Skin conditions have a large emotional, psychological and psychiatric impact on the individual. The All-Party Parliamentary Group on Skin (APPGS) commissioned a qualitative survey to further explore this relationship alongside the experiences of those accessing services in relation to these difficulties in the UK.

AIM

To examine the experiences of UK individuals living with a skin condition, and their views of seeking and receiving psychological treatment. This survey formed part of the evidence collected in the preparation of the APPGS Mental Health and Skin Disease report.

METHODS

A free-text electronic survey was widely distributed by professional bodies and skin-related charities. Responses were analysed using descriptive thematic analysis and descriptive statistics. Data for each question were classified and labelled, leading to the development of a coding frame. Inter-rater reliability was assessed using Cohen kappa statistic.

RESULTS

In total, 544 participants (84% female) completed the survey. The majority of respondents had inflammatory skin diseases such as eczema (43%) or psoriasis (33%). The thematic analysis revealed five key themes associated with impact on mood; impact of intimacy; impact on activities of daily living; lack of recognition from others of the impact; and lack of accessible services.

CONCLUSION

The survey demonstrates that there is an urgent need to improve both awareness of the impact that skin conditions can have, and for the provision of psychological services to address this impact.

28 Effect of deuterium oxide on bovine oocyte cryotolerance

It is known that cryopreservation triggers spindle disassembly, increased aneuploidy risk, decreased post-thaw survival, fertilization, and embryo development. We hypothesised that a treatment with D2O before vitrification would slow down oocyte metabolism and reduce ice crystal formation by replacing water inside the cells. The aim of the study was to evaluate the effect of a 4-h treatment with different D2O concentrations (0, 3, 15, and 30%) on cryotolerance of bovine in vitro-matured oocytes. Abattoir-derived bovine oocytes were matured in vitro for 20h in TCM-199 medium with 15% of bovine serum (BS), 0.5µg mL−1 of FSH, 5µg mL−1 of LH, 0.8mM l-glutamine, and 50µg mL−1 of gentamicin at 39°C with 5% of CO2 and randomly divided into 5 experimental groups. A group of non-vitrified oocytes was used as the fresh oocyte control group, whereas the remaining oocytes were incubated for 4h in in vitro maturation medium with 0% (vitrified control; n=205), 3% (n=205), 15% (n=205), and 30% D2O (n=205) before vitrification. The experiment was repeated 4 times. Oocytes were denuded in HEPES-buffered TCM-199 (H199)+5% BS and vitrified using a cryotop freezing straw. The oocytes were incubated in 200μL of H199+20% BS with 7.5% ethylene glycol and 7.5% dimethyl sulfoxide for 3min. After that, oocytes were collected in 50μL of H199+20% fetal bovine serum with 15% ethylene glycol+15% dimethyl sulfoxide and 0.5M sucrose for 20s and plunged into LN2. One month later, oocytes were warmed in thawing media with decreasing concentrations of sucrose (1.35M to 0.31M) and then placed into in vitro maturation medium for 2h before IVF. Matured oocytes were IVF and cultured according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347-1355). Cleavage and blastocyst rates were evaluated after 7 days of culture. Data were analysed using the GLM procedure of SPSS (SPSS Inc., Chicago, IL, USA). The least statistical difference post-hoc test was used to perform statistical multiple comparison. The α-level was set at 0.05. As expected, both cleavage [60.5±4.6 (fresh control); 36.9±2.6 (0% D2O); 46.3±3.7 (3% D2O); 31.6±2.4 (15% D2O); and 24.4±2.6 (30% D2O)] and blastocyst rates [25.7±0.8 (fresh control); 9.0±0.8 (0% D2O); 9.0±0.7 (3% D2O); 3.6±0.2 (15% D2O); and 4.3±0.8 (30% D2O)] decreased in all vitrified groups compared with the fresh control group. Within vitrified oocytes, cleavage rate increased (P<0.05) with 3% D2O treatment compared with the other groups. However, pretreatment with higher (15-30%) D2O concentrations decreased (P<0.05) blastocyst rates of vitrified-warmed oocytes. In conclusion, a pretreatment with low concentrations (3%) of D2O improved the cleavage rate of bovine vitrified-warmed oocytes, suggesting a potential beneficial effect, whereas deleterious effects were observed using the higher concentrations. Therefore, further studies are required to assess a potential use of D2O to improve oocyte cryotolerance, likely testing different incubation times.

184 Effect of selenium on the differentiation of porcine adipose-derived stem cells into osteoblasts

Bone damage is a common occurrence and although traditional bone healing methods work well, they are not always able to fix all issues pertaining to the injury. However, recent research on stem cell therapies using adipose-derived stem cells (ASC) has shown that ASC that differentiate into osteoblasts can be used as a potentially better solution for bone injuries. Selenium is a nutritional trace element that has been found to be essential in the production of selenoproteins and bone growth. Selenium plays an integral role in osteoblast cell differentiation and proliferation. The aim of this experiment was to test whether adding selenium to osteogenic influences the differentiation potential of ASC into osteoblasts. Porcine ASC were isolated as described (Monaco et al. 2009, Open Tissue Eng. Regen. Med. J. 2, 20-33). Seven different treatments were given to the cells: a negative control of DMEM, a positive control of osteogenic medium, and 5 concentrations of selenium in the osteogenic medium (10, 5, 1, 0.5, and 0.1 µM). Medium was changed twice a week for 4 weeks, at the end of which the cells were stained with Alizarin Red S stain. The number of osteoblastic nodules in each well were counted and divided into the categories of “forming” and “formed.” A generalized linear model (GLM) procedure (SPSS Inc./IBM Corp., Chicago, IL, USA) was used to analyse the data. The least statistical difference (l.s.d.) post hoc test was used to perform statistical multiple comparison with an α-level of 0.05. The results showed (Table 1) that medium containing selenium concentrations of 0.1, 0.5, and 1.0 µM were able to develop more nodules than the osteogenic medium. There was no statistical difference in the total amount of forming and formed nodules in those 4 groups; however, there was a statistical tendency for a difference (P=0.06) between the medium with 1 µM selenium and the osteogenic medium. Medium containing 10 or 5 µM selenium had lower nodule counts (both forming and formed) than osteogenic medium. There was no statistical difference between 10 µM and DMEM. These results suggest that low concentrations of selenium have a positive effect on nodule formation, whereas higher concentrations are detrimental. Table 1.The average number (standard deviations in parentheses) of formed, forming, and total osteoblastic nodules in each of the different treatments

208 The effect of copper on the differentiation of adipose-derived stem cells into osteoblasts

Large bone defects present a tremendous challenge to the treating surgeon. Tissue engineering using scaffolds of various sizes and shapes that contain stem cells and other osteoinductive molecules offer a potential solution to this difficult problem. The aim of this project was to evaluate whether osteogenic medium infused with copper influences the differentiation of adipose-derived stem cells (ASC) into osteoblasts. Copper is a key cofactor for lysyl oxidase, an enzyme involved in producing a collagen matrix through which bone can grow. Lysyl oxidase expression is up-regulated in bone marrow stromal cells (Khosravi et al. 2014 PLoS One 9, e100669). Our hypothesis was that the presence of copper in the osteogenic medium would positively influence the number of osteoblastic nodules formed. Swine ASC were isolated as described (Monaco et al. 2009 Open Tissue Eng. Regen. Med. J. 2, 20-33). The ASC were divided in 7 different treatments: 5 concentrations of copper in the osteogenic medium (0.1, 1, 10, 50, and 100 µM) plus 2 control treatments (osteogenic medium without copper and a negative control, DMEM). The medium was changed twice a week for 4 weeks. The experiment was replicated 6 times. At the end of the culture period, cells were stained with Alizarin Red S and Von Kossa stains. In each well, we counted the total number of nodules that were either formed or forming. Data were analysed using the generalized linear model (GLM) procedure (SPSS Inc./IBM Corp., Armonk, NY). The least significant difference (l.s.d.) post hoc test was used to perform statistical multiple comparison. The α-level was set at 0.05. The results showed that more nodules were formed in the 0.1 and 1 µM copper groups compared with the osteogenic control, but there was no statistical difference between those 2 treatments. Table 1 illustrates the total number of formed and forming nodules in addition to their standard deviation. There was a positive effect on nodule formation when copper concentrations of 0.1 and 1 µM were added to the osteogenic medium. In contrast, copper concentrations of 50 and 100 µM had a cytotoxic effect. These results confirm that low concentrations of copper have a positive effect on osteogenesis. This preliminary experiment is the first step towards the analysis of the behaviour of ASC on scaffolds with copper incorporated into their matrix. Table 1.The average number (standard deviations in parentheses) of total formed and forming osteoblast nodules compared between treatment groups

Genotypes, phenotypes and whole genome sequence: Approaches from the My Life Our Future haemophilia project

INTRODUCTION

Information from the genes encoding factor VIII (F8) and IX (F9) is used in reproductive planning and to inform inhibitor formation, bleeding severity and response to therapies. Advances in technology and our understanding of the human genome now allows more comprehensive methods to study genomic variation and its impact on haemophilia.

AIMS

The My Life Our Future (MLOF) programme was begun in 2012 to provide genetic analysis and to expand research in haemophilia through a research repository.

METHODS

MLOF enrolled haemophilia A and B patients followed at haemophilia treatment centers in the U.S., including, since 2015, known and potential genetic carriers. Initial F8 and F9 DNA analysis was performed utilizing a next generation sequencing approach which allowed simultaneous detection of F8 inversions and other variants. Candidate variants were confirmed using a second method and multiplex ligation-dependent probe amplification was used to detect structural variants.

RESULTS

The initial phase of MLOF completed enrollment in December 2017 with 11,356 patients, genetic carriers, and potential carriers enrolled. In the 9453 subjects in whom analysis is complete, 687 unique previously unreported variants were found. Simultaneous sequencing of the F8 and F9 genes resulted in identification of non-deleterious variants previously reported as causative in haemophilia. DNA from 5141 MLOF subjects has undergone whole genome sequencing through the NHLBI TOPMed programme of the U.S. NIH.

CONCLUSION

MLOF has provided genetic information for patients and their families to help inform clinical care and has established a repository of data and biospecimens to further advance haemophilia research.

Looking after the mouth - Evaluation of a pilot for a new approach to training care home carers in Kent, Surrey and Sussex

Objective This pilot study aimed to produce and evaluate training resources and training in oral health care, including oral hygiene, for carers in care homes in Surrey and Medway.Methods During two training days, for carers from these homes, short, interactive presentations were given on a range of topics relevant to oral health care and oral hygiene of older people, followed by practical training. Prior to any training all attendees completed a 39 question questionnaire to establish their baseline knowledge of oral health and hygiene. At the end of the training day they completed an evaluation form. Fourteen weeks later, they were visited at their place of work and completed the same questionnaire again. Differences in responses between baseline and after 14 weeks were statistically tested using the chi-squared test.Results Sixty-six carers attended the training sessions and 44 were followed up 14 weeks later. The results showed an improvement in carer knowledge at follow up. The majority of carers (36/44) spoke English as their first language. They had a mean age of 41 years, 37 were female and 7 male. They had worked as carers for a mean of 10.9 years (range 4 months-34 years). Over 90% stated that the training day fully met or exceeded their requirements and expectations.Conclusions The results indicated improvements in carer knowledge. However, the carers were atypical of carers in general, as they were self-selected and well-motivated. Nevertheless the content of the training day and the questionnaire should inform future work in this area.

155 Oocyte Maturation in Lyophilized In Vitro Maturation Medium as a Method to Increase the Medium’s Shelf-Life

The in vitro production of bovine embryos has dramatically increased in recent years, and with it the demand of stable media with a long shelf-life. In this experiment we evaluated the impact of the freeze-dried in vitro maturation (IVM) medium (Mdry) on in vitro oocyte maturation. We compared the standard IVM and the Mdry media. Medium M199 was used as base for the IVM medium. The percentage of metaphase II oocytes and embryo production were evaluated. Media solutions (10 mL) were aliquoted into 50-mL conical tubes and lyophilized to form a powder concentrate using a Genesis freeze-dryer (VirTis, Gardener, NY, USA). Lyophilization consisted of a constant cooling from 20°C to –10°C at a constant rate of 1°C/min with a 2-h hold at –10°C before sublimation at 0°C. The Mdry medium was held at –80°C for 4 months (only serum and hormones were added before the incubation). When the IVM medium was rehydrated, the pH were adjusted to 7.4. The percentage of mature oocytes was evaluated after 24 h of maturation. The oocytes were stained with Hoechst 33342, and only oocytes with metaphase and a polar body were evaluated as matured. Abattoir-derived Holstein oocytes (n = 540) were in vitro matured (25–30/well in 400 µL) and fertilized with sexed semen, according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347-1355). The oocytes were split for analysis (432 were used for IVP and 108 for maturation rate) over 6 replicates. Twenty hours after IVF, presumptive zygotes were cultured in SOF medium at 39°C with 5% CO2, 7% O2, and 88% N2. On Day 7, embryo yields were assessed. All recorded parameters were subjected to a Student’s t-test. The parameters compared were maturation rate, cleavage rate, blastocyst rate and the percentage of embryos cleaved. The α level was set at 0.05. All data were expressed as quadratic means and mean standard deviations. The results showed no differences between the 2 groups (75.9% v. 74.1%) (t = 0.37; SD = 12.69; P = 0.36; df = 5) when we compared the nuclear maturation; however, when we evaluated embryo production, we found the Mdry treatment had a higher cleavage percentage (t = 2.39; SD = 14.81; P = 0.02; df = 5) and total embryos produced (t = 2.49; SD = 5.6; P = 0.02; df = 5) compared with the control (Table 1.). These results showed that lyophilization can be a valid method to increase the shelf life of IVP media. More replicates must be done in order to understand why the freeze-dried media produced more embryos. Table 1.Mean (SD in parentheses) percentage cleavage and blastocysts

123 In Vitro Embryo Production in Lyophilized In Vitro Culture Medium as a Method to Increase the Medium's Shelf-Life

The worldwide production of livestock embryos requires stable medium with long shelf life. In this experiment, we evaluated the impact of the freeze-dried in vitro culture (IVC) medium (Mdry) on in vitro embryo production. We compared the standard IVC and Mdry media for cleavage rate and embryo production. Media solutions (10 mL) were aliquoted into 50-mL conical tubes and lyophilized to form a powder concentrate using a Genesis freeze-dryer (VirTis, Gardener, NY, USA). Lyophilization consisted of a constant cooling from 20°C to –10°C at a constant rate of 1°C/min with a 2-h hold at –10°C before sublimation at 0°C. Mdry medium were held at –80°C for 4 months. When the IVC medium was rehydrated, the pH were adjusted to 7.4. Abattoir-derived Holstein oocytes (n = 618, in 7 replicates) were in vitro matured and fertilized with sexed semen, according to standard procedures (Rubessa et al. 2011 Theriogenology 76, 1347-1355). Twenty hours after IVF, presumptive zygotes were cultured in SOF medium with 5% BS at 39°C with 5% CO2, 7% O2, and 88% N2. On Day 7, embryo yields were assessed. All recorded parameters were subjected to a Chi-Square Test 2 × 2. The parameters compared were percent cleavage, blastocysts, and embryos/cleaved. The α level was set at 0.05. All data were expressed as quadratic means and mean standard errors. The results (Table 1) showed not a statistical difference between control and Mdry. The Mdry had a higher percentage of cleaved zygotes (65.4% v. 53.4%) but not enough for a statistical difference. However, when we compared embryo production, there was no difference between treatments. The ratio between blastocysts and cleaved embryos was higher in the control group but not significant according to our selected α level. These results indicate that it is possible lyophilize IVC medium without interfering with the potential quality of the medium. Further studies will be needed to better understand the positive effect of the lyophilization on the cleavage rate. Table 1.Mean (SD in parentheses) percentage cleavage and blastocysts

140 COMPARISON OF 3 DIFFERENT METHODS TO SELECT HIGH SPERM QUALITY FOR IVF

Sperm selection is a fundamental step for IVF, influencing treatment and the health of offspring. Over the years, several techniques have been tested to recover highly motile sperm, including centrifugation with discontinuous gradients and numerous filtration procedures. In our previous paper, we showed that it is possible, in ~20 min, to select a high quality sperm population using an electric charge in a microchannel device. This method produced the same blastocyst rates as a discontinuous gradient (DG), but in less time [25 min less; Rubessa et al. 2016 Andrology (Los Angeles) 5]. This technique takes advantage of one of the physiological characteristics of high quality sperm; that is, the head has a negative electric charge. The aim of the present experiment was to analyse the characteristics of the sperm selected with our device. We compared 2 standard sperm procedures and our device, with semen assessed using a computer-assisted sperm analyzer to evaluate the principal sperm parameters. Standard procedures were used to select sperm by DG and swim-up (SU). Thawed semen was pipetted into the microchannel of our device and then exposed to the electric charge (10 V) for 10 min [Rubessa et al. 2016 Andrology (Los Angeles) 5]. For each replicate, 3 straws of frozen bovine semen were thawed at 37°C for 40 s and pooled. The pooled sample was divided into 3 aliquots: one for each technique, 5 replicates of the experiment were performed. Data were analysed by ANOVA using the general linear model (GLM) procedure (SPSS Inc., Chicago, IL, USA). Bonferroni’s post hoc test was used to perform statistical multiple comparison. The α-level was set at 0.05. The results show an effect of the method all motility parameters are not significantly different, although some of the motility parameters were statistically different (P < 0.05). (P < 0.05). The beat cross frequency results were 23 ± 2.4 v. 37.7 ± 2.1 v. 19.5 ± 0.7 (µm/s) for DG, SU, and EC. The same statistical differences were found for the STR (straightness): 75 ± 3.5 v. 84.5 ± 2.0 v. 62.3 ± 2.4 (µm/s), and LIN (linearity): 39.8 ± 4.4 v. 53 ± 1.2 and 31.8 ± 1.4. These results confirmed the potential of this new device, and that it is possible to use this new method to select high motility sperm without harming sperm characteristics. These results showed that our device produced the same quality of sperm obtained with DG and SU but in as little as 20 min.