Biomedical doctoral students' research practices when facing dilemmas: two vignette-based randomized control trials

Our aim was to describe the research practices of doctoral students facing a dilemma to research integrity and to assess the impact of inappropriate research environments, i.e. exposure to (a) a post-doctoral researcher who committed a Detrimental Research Practice (DRP) in a similar situation and (b) a supervisor who did not oppose the DRP. We conducted two 2-arm, parallel-group randomized controlled trials. We created 10 vignettes describing a realistic dilemma with two alternative courses of action (good practice versus DRP). 630 PhD students were randomized through an online system to a vignette (a) with (n = 151) or without (n = 164) exposure to a post-doctoral researcher; (b) with (n = 155) or without (n = 160) exposure to a supervisor. The primary outcome was a score from - 5 to + 5, where positive scores indicated the choice of DRP and negative scores indicated good practice. Overall, 37% of unexposed participants chose to commit DRP with important variation across vignettes (minimum 10%; maximum 66%). The mean difference [95%CI] was 0.17 [- 0.65 to 0.99;], p = 0.65 when exposed to the post-doctoral researcher, and 0.79 [- 0.38; 1.94], p = 0.16, when exposed to the supervisor. In conclusion, we did not find evidence of an impact of postdoctoral researchers and supervisors on student research practices.Trial registration: NCT04263805, NCT04263506 (registration date 11 February 2020).

Metastatic melanoma to the ovary in pregnancy: A case report

•

Metastatic melanoma to the ovary is uncommon and can occur years after initial diagnosis.

•

Ovarian metastatic melanoma can mimic various benign lesions on imaging and clinical history is key.

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If any suspicion in pregnancy, placenta should be evaluated due to possibility of transplacental transmission.

Metastatic melanoma to the ovary is an uncommon presentation. We report a case of metastatic melanoma to the ovary that presented as a growing left adnexal mass during pregnancy and was thought to be benign by imaging and frozen section pathology. Here we discuss the challenges in radiologic and pathologic diagnosis, as well as considerations for the mother and newborn.

Laminar airflow versus turbulent airflow in simulated total hip arthroplasty: measurements of colony-forming units, particles, and energy consumption

BACKGROUND

The optimal type of ventilation in operating theatres for joint arthroplasty has been debated for decades. Recently, the World Health Organization changed its recommendations based on articles that have since been criticized. The economic and environmental impact of ventilation is also currently an important research topic but has not been well investigated.

AIM

To compare how large, high-volume, laminar airflow (LAF) and turbulent airflow (TAF) ventilation systems perform during standardized simulated total hip arthroplasty (THA), as they pertain to colony-forming units (cfu), particle counts, and energy consumption.

METHODS

Two identical operating theatres were used to perform simulated THA. The only difference was that one was equipped with LAF and the other with TAF. Cfu and particles were collected from key points in the operating theatre, and energy was measured for each simulation. Thirty-two simulations were done in total.

FINDINGS

LAF had significantly reduced cfu and particle count when compared with TAF, at both 100% and 50% air influx. Furthermore, it was shown that lowering the air influx by 50% in LAF did not significantly affect cfu or particles, although reducing the fresh air influx from 100% to 50% significantly lowered the energy consumption. Most simulations in TAF did not meet the cleanroom requirements.

CONCLUSION

Cfu were significantly lower in LAF at both 100% and 50% air influx. It is possible to reduce fresh air influx in LAF operating theatres by 50%, significantly reducing energy consumption, while still maintaining cfu and particle counts below the ISO classification threshold required for THA surgery.

OP0157-HPR CHANGES IN PAIN AND HAND FUNCTION AFTER MULTIMODAL OCCUPATIONAL THERAPY AND/OR SURGERY IN PATIENTS WITH CARPOMETACARPAL OSTEOARTHRITIS

Background:

Carpometacarpal osteoarthritis (CMC1 OA) is a subset of hand OA, often leading to pain and functional limitations. The EULAR recommends conservative treatment as first-line management, and a recent study showed significant short-term effect of multimodal occupational therapy on pain and hand function in patients referred to surgical consultation1. However, long-term results are lacking.

Objectives:

To explore the long-term effect of multimodal occupational therapy on pain and hand function in patients with CMC1 OA, and to assess the differences between those undergoing surgery or not in the two groups.

Methods:

This project presents secondary analyses of a multicentre RCT. Patients referred by their general practitioner to surgical consultation due to CMC1 OA at three Norwegian hospitals from 2013-2015 were eligible. During the waiting period between referral and surgical consultation, 180 patients were randomized to usual care (information, n=90) or a 3-month multimodal occupational therapy intervention (patient education, hand exercises, orthoses and assistive devices, n=90). Patients were assessed at baseline, and 4 (before surgical consultation), 18 and 24 months. Pain at rest was assessed using a 11-point numeric rating scale, and hand function was self-reported with the MAP-Hand (1-4, 1=no problem). The long-term within- and between-group differences on pain and hand function were assessed using repeated measure ANOVA. Sub-analyses were done among those undergoing surgery or not in the two groups. P-value <0.05.

Results:

163 patients (63 (8) years, 81% women) were included in the analyses. Both groups showed a significant reduction in pain and improvement in hand function over time (p<0.001), with a significant between-group difference for pain (F (1, 161) = 8.56, p = 0.004), in favour of the intervention group, but not hand function.

After 2 years, 22 patients had undergone surgery in the intervention group vs 29 in the control group. No significant difference over time were found in pain or hand function between those undergoing surgery or not in the two groups. However, at the time of the surgical consultation, significantly higher pain (Figure 1) and poorer hand function were reported among those later undergoing surgery in the control group (p≤0.001). Surgery did not lead to further improvement in pain and hand function in the intervention group.

Figure 1.

Between-group difference on pain over a 2-year period. The control group is marked in light grey and the intervention group in black. Those who underwent surgery are marked with dotted lines, while those who did not are marked with solid lines (n=163)

Conclusion:

The results showed that the positive effect of multimodal occupational therapy on pain and hand function persisted over the 2-year period, however, no significant between-groups difference over time was found. No significant between-group differences were found when dividing into sub-groups, however, those later undergoing surgery in the control group scored significantly worse on pain and hand function at the time of surgical consultation. The results may imply that patients who would benefit from surgery were identified, and that surgery does not give an additional benefit in patients who have received multimodal occupational therapy. This needs to be further investigated.

References:

[1]Tveter AT, Østerås N, Nossum R, Eide REM, Klokkeide Å, Hoegh Matre K, et al. Short-term effects of occupational therapy on hand function and pain in patients with carpometacarpal osteoarthritis: secondary analyses from a randomized controlled trial. Arthritis care & research. 2020:10.1002/acr.24543

Acknowledgements:

We would like to acknowledge Øyvor Andreassen for her contribution throughout the project as a patient representative.

Disclosure of Interests:

None declared

Simple cardiovascular risk stratification using anthropometric measures instead of serum cholesterol. The MORGAM Prospective Cohort Project

Background

Body composition predicts cardiovascular outcomes, but it is uncertain whether anthropometric measures can replace the more expensive serum total cholesterol for cardiovascular risk stratification in low resource settings.

Purpose

The purpose of the study was to compare the additive prognostic ability of serum total cholesterol with that of body mass index (BMI), waist/hip ratio (WHR), and estimated fat mass (EFM, calculated using a validated prediction equation), individually and combined.

Methods

We used data from the MORGAM (MONICA, Risk, Genetics, Archiving, and Monograph) Prospective Cohort Project, an international pooling of cardiovascular cohorts, to determine the relationship between anthropometric measures, serum cholesterol, and cardiovascular events, using multivariable Cox proportional-hazards regression analysis. We further investigated the ability of these measures to enhance prognostication beyond a simpler prediction model, consisting of age, sex, smoking status, systolic blood pressures, and country, using comparison of area under the receiver operating characteristics curve (AUCROC) derived from binary logistic regression models. The primary endpoint was major adverse cardiovascular events (MACE), defined as a composite of death from coronary heart disease, myocardial infarction, or stroke.

Results

The study population consisted of 52,188 apparently healthy subjects (56.3% men) aged 47±12 years ranging from 20 to 84, derived from 37 European cohorts, with baseline between 1982–2002 all followed for 10 years during which MACE occurred in 2465 (4.7%) subjects. All anthropometric measures (BMI: hazard ratio (HR) 1.04 [95% confidence interval (CI): 1.03–1.05] per kg/m2; WHR: HR 7.5 [4.0–14.0] per unit; EFM: HR 1.02 [1.01–1.02] per kg) as well as serum total cholesterol (HR 1.20 [1.16–1.24] per mmol/l) were significantly associated with MACE (P&lt;0.001 for all), independently of age, sex, smoking status, systolic blood pressures, and country. The addition of serum cholesterol significantly improved the predictive ability of the simple model (AUCROC 0.818 vs. 0.814, P&lt;0.001), as did the combination of WHR, BMI, and EFM (AUCROC 0.817 vs. 0.814, P=0.004). When assessed individually, BMI (AUCROC 0.816 vs. 0.814, P=0.004) and WHR (AUCROC 0.815 vs. 0.814, P=0.02) improved model performance, while EFM narrowly missed significance (AUCROC 0.815 vs. 0.814, P=0.06). There was no significant difference in the predictive ability of a model including serum cholesterol versus that including all three anthropometric measures (AUCROC 0.818 vs. 0.817, P=0.13). The figure shows the pertinent areas under the ROC curve in predicting MACE.

Conclusion

In this large population-based cohort study, the addition of a combination of anthropometric measures, i.e. BMI, WHR, and EFM, raised the predictive ability of a simple prognostic model comparable to that obtained by the addition of serum total cholesterol.

Figure 1

Funding Acknowledgement

Type of funding source: None

FRI0635-HPR PATIENTS’ MOTIVATION AND GOALS FOR THUMB CARPOMETACARPAL OSTEOARTHRITIS SURGERY

Background:

Osteoarthritis (OA) in the thumb carpometacarpal joint (CMCJ) is a prevalent disease which may lead to structural damage, severe pain and functional limitations, but for which there is yet no cure. Evidence-based treatment recommendations state that all patients with hand OA should be offered patient education, hand exercises, and provision of assistive devices and orthoses. Pharmacological therapy is recommended as a symptom relieving supplement. The main indication for CMCJ surgery is pain and poor function, and such surgery should be considered only when other treatment has proven insufficient in relieving pain (1). Previous research has shown that high motivation is a significant predictor for deciding to undergo CMCJ surgery (2), but there is little knowledge regarding which factors that motivates patients for undergoing such surgery.

Objectives:

The objective of this study was to explore patient goals and motivation for surgery, and factors characterizing patients highly motivated for surgery.

Methods:

This cross-sectional study included 180 patients referred from their general practitioner for CMCJ surgical consultation. Goals for surgery were collected with an open-ended question and analysed by linking the content of each goal to domains in the International Classification of Functioning, Disability and Health coding system. Motivation for surgery was rated with a Numeric Rating Scale (NRS, 0-10, 0=no motivation). Activity limitations was self-reported using the Measure of Activity Performance of the Hand (MAP-Hand, score 1 to 4, 1=no activity problems) and the Disabilities of the Arm, Shoulder and Hand questionnaire (QuickDASH; score 0-100, 0=no disability). Factors that characterized patients highly motivated for surgery (NRS≥8) were explored with multivariate regression analyses.

Results:

Mean age of participants was 63 years (SD 7.6) and 142 (79%) were women. The most common goals for surgery were to reduce pain and improve arm and hand use. Fifty-six (31%) of the patients were characterized as highly motivated for surgery. High motivation for surgery was strongly associated with more activity limitations (MAP-Hand; (OR 4.00, p=0.008)), living alone (OR 3.18, p=0.007) and a young age (OR 0.94, p=0.002).

Conclusion:

Decisions on CMCJ OA surgery should be based on assessment and discussion of patients’ life situation, hand pain, activity limitations and motivation and goals for surgery. According to the EULAR recommendations, previously received conservative and pharmacological treatment should also be evaluated.

References:

[1] Kloppenburg, M., et al. (2018). “2018 update of the EULAR recommendations for the management of hand osteoarthritis.” Ann Rheum Dis. 0; 1-9

[2] Gravas, E. M. H., et al. (2019). “Non-pharmacological treatment gap preceding surgical consultation in thumb carpometacarpal osteoarthritis - a cross-sectional study.” BMC Musculoskelet Disord 20(1): 180.

Disclosure of Interests:

None declared

OP0152-HPR A COST-UTILITY ANALYSIS OF MULTIMODAL OCCUPATIONAL THERAPY IN PATIENTS WITH THUMB BASE OSTEOARTHRITIS

Background:

Patient education, hand exercises, and use of assistive devices and orthoses are regarded as first-line treatment for patients with hand osteoarthritis (OA) (1), however there is limited evidence for the cost-effectiveness of such treatment.

Objectives:

The objective of this study is to assess the cost-utility of a multimodal occupational therapy treatment delivered in the waiting period before surgical consultation in patients with thumb base OA compared to usual care.

Methods:

This study presents an economic evaluation assessing the difference in health care use and quality-of-life during a 24-month period in a Norwegian multicenter randomized controlled trial. All patients referred to surgical consultation due to thumb base OA at three departments of rheumatology between 2013 and 2015 were eligible for inclusion. In total, 180 patients were included and randomized to a control group or a multimodal occupational therapy group (90 patients in each group). During the waiting period between referral and actual surgical consultation, the control group continued with usual care which was staying on the waiting list and receiving information on hand OA. The intervention group got information on hand OA, ergonomic principles and use of assistive devices, and they were instructed in home-based hand exercises and received a day and a night orthosis. The intervention group was instructed to use the orthoses and assistive devices as much as possible and perform home exercises three times per week for 12 weeks. The patients were assessed at baseline and after 4, 18 and 24 months. The within-trial economic analysis reports the incremental cost-effectiveness ratio (ICER) reflecting the between-group difference in incremental cost per adjusted life years (QALY) over 24 months. A generic health-related quality of life questionnaire, the EuroQol 5 Dimension, was used to calculate the QALYs at baseline, 4, 18 and 24 months. Costs were collected from different sources, taking a health care perspective; The occupation therapist reported the number of consultations related to the intervention; surgical procedure and post-operative follow-up were collected from patients’ journals; and additional consumption of primary and specialist health care was self-reported by the patient. Sensitivity analyses were performed. The results are presented in a cost-effectiveness plane using bootstrapping. Willingness-to-pay threshold is set to be € 27 500 linked to the severity of this condition.

Results:

The mean age of the included patients was 63 years (SD 7.6) and 79% were women. There was a total between-group difference in QALYs of 0.07 utilities after 24 months, in favour of the intervention group. Operations constituted the main costs with 22 operations in the intervention group compared to 33 in the control group. The between-group difference in costs due to health care consumption was estimated to € 500 in favour of the intervention group (Figure 1).

Conclusion:

The results in this within-trial analysis indicate that multimodal occupational therapy in the waiting period before surgical consultation compared to usual care is a cost-effective alternative taking a health care perspective.

References:

[1]Kloppenburg, M., et al. (2018). “2018 update of the EULAR recommendations for the management of hand osteoarthritis.”Ann Rheum Dis.

Disclosure of Interests:

None declared

0451 Fully Automatic Detection of Sleep Disordered Breathing Events

Introduction

Evaluation of sleep apnea involves manual annotation of Polysomnography (PSG) file, a time-consuming process subject to interscorer variations. The DOSED algorithm has been shown to be helpful in detecting Central Sleep Apnea (CSA), Obstructive Sleep Apnea (OSA), and Hypopnea when merged into a single event type. This work uses a modified version of DOSED capable of detecting each event type separately.

Methods

The network consists of 3 blocks of 1D convolutional layers followed by 6 blocks of 2D convolutional layers. The network has 2 classification layers, one determines the probability of each class, and the other determines the start and duration time of the event with the highest probability. Four channels from nasal and mouth airflow and position of abdomen and thorax are used as input to the model. The model was trained using 2800 PSG from 4 different cohorts (MESA, MROS, SSC, WSC) and tested on 70 PSG, which have been scored by six technicians (Stanford, U Penn, St Louis).

Results

On an event by event basis, model F1-scores versus a weighted consensus score based on 6 technicians were 0.60 for OSA, 0.43 for CSA, and 0.34 for Hypopnea. Average F1-scores for the 6 technicians were 0.48 (std 0.04) for OSA, 0.29 (std 0.145) for CSA, and 0.54 (std 0.183) for Hypopnea, indicating that the model functions better on an event-by-event basis than an average technician. Correlations between indices/hr for central apnea, obstructive apnea, and hypopnea indicate excellent correlations for apneas, but poor correlation for hypopnea. We are now adding the snoring channel to explore if predictions can be improved.

Conclusion

The result shows that deep learning-based models can detect respiratory events with an accuracy similar to technicians. The poor agreement between technicians from different universities indicates that we need better definitions of hypopnea.

Support

 

1208 Sleep Stage Prediction And Sleep Disordered Breathing Detection Using Raw Actigraphy And Photoplethysmography From Wearable Consumer Device

Introduction

Wearable, multisensory consumer devices that estimate sleep are prevalent and hold great potential. Most validated actigraphic prediction studies of sleep stages (SS) have only used low resolution (30 sec) data and the Cole-Kripke algorithm. Other algorithms are often proprietary and not accessible or validated. We present an automatic, data-driven deep learning algorithm that process raw actigraphy (ACC) and photoplethysmography (PPG) using a low-cost consumer device at high (25Hz) and low resolution to predict SS and to detect sleep disordered breathing (SDB) events.

Methods

Our automatic, data-driven algorithm is a deep neural network trained and evaluated to predict SS and SDB events on 236 recordings of ACC data from a wrist-worn accelerometer and PPG data from the overlapping PSG. The network was tested on raw ACC and PPG data, which was collected at 25 Hz using the HUAMI Arc2 wristband from 39 participants that underwent a nocturnal polysomnography (PSG).

Results

Overall accuracy (Acc), recall (Re), specificity (Sp), and kappa (κ) per subject on the test dataset the prediction of wake, NREM, REM was Acc=76.6%, Re=72.4%, Sp=78.0%, kappa=0.42. On average, we found a 7 % higher performance using the raw sensor data as input instead of processed, low resolution inputs. PPG was especially useful for REM detection. The network assigned 55.6% of patients to the correct SDB severity group when using an apnea-hypopnea index above 15.

Conclusion

Current results show that SS prediction is significantly improved when using the raw sensor data; it indicates that the system holds promise as a potential pervasive monitoring device for patients with chronic sleep disorders. In contrast the system did not show potential as a sleep apnea screening tool. Additional studies are ongoing to examine the effects of pathology such as sleep apnea and periodic leg movement on SS prediction.

Support

Technical University of Denmark; University of Copenhagen, Copenhagen Center for Health Technology, Klarman Family Foundation.

Correction to: High-throughput method for ear phenotyping and kernel weight estimation in maize using ear digital imaging

[This corrects the article DOI: 10.1186/s13007-018-0317-4.].

Use of test accuracy study design labels in NICE's diagnostic guidance

BACKGROUND

A variety of study designs are available to evaluate the accuracy of tests, but the terms used to describe these designs seem to lack clarity and standardization. We investigated if this was the case in the diagnostic guidance of the National Institute of Care and Health Excellence (NICE), an influential source of advice on the value of tests.

OBJECTIVES

To describe the range of study design terms and labels used to distinguish study designs in NICE Diagnostic Guidance and the underlying evidence reports.

METHODS

We carefully examined all NICE Diagnostic Guidance that has been developed from inception in 2011 until 2018 and the corresponding diagnostic assessment reports that summarized the evidence, focusing on guidance where tests were considered for diagnosis. We abstracted labels used to describe study designs and investigated what labels were used when studies were weighted differently because of their design (in terms of validity of evidence), in relevant sections. We made a descriptive analysis to assess the range of labels and also categorized labels by design features.

RESULTS

From a total of 36 pieces of guidance, 20 (56%) were eligible and 17 (47%) were included in our analysis. We identified 53 unique design labels, of which 19 (36%) were specific to diagnostic test accuracy designs. These referred to a total of 12 study design features. Labels were used in assigning different weights to studies in seven of the reports (41%) but never in the guidance documents.

CONCLUSION

Our study confirms a lack of clarity and standardization of test accuracy study design terms. There seems to be scope to reduce and harmonize the number of terms and still capture the design features that were deemed influential by those compiling the evidence reports. This should help decision makers in quickly identifying subgroups of included studies that should be weighted differently because their designs are more susceptible to bias.

Extended evaluation of urinary multi-biomarker analyses of mycotoxins in Swedish adults and children

Biomarker-based methods are being more and more used to assess dietary exposure of mycotoxins in a population. The aim of the present study was to perform an extended analysis of urinary multiple mycotoxin levels and associations with background characteristics and food groups. Exposure assessment calculations were performed on three urine mycotoxins as described below and the probable daily intake (PDI) was compared with the established tolerable daily intake (TDI) to uncover potential exposure risks. The study population consisted of 250 adults and 50 school children in grade five from two surveys conducted by the Swedish National Food Agency. Six mycotoxins (deoxynivalenol (DON), zearalenone (ZEA), fumonisin B1 (FB1), fumonisin B2 (FB2), ochratoxin A (OTA), and nivalenol (NIV) and four metabolites (deepoxy-deoxynivalenol (DOM-1), aflatoxin M1 (AFM1), α-zearalenol (α-ZOL) and β-zearalenol (β-ZOL) were measured by an ultra-performance liquid chromatography tandem mass spectrometry based method (LC-MS/MS). OTA and DON were the most commonly occurring mycotoxins in urine of both adults and children, 51 and 63%, respectively in adults and 96 and 94%, respectively in children. A positive correlation was found between urinary NIV and total cereal consumption among adults. ZEA, α-ZOL, β-ZOL and FB2 were significantly higher in females than males (P<0.01 for all). Adjusted OTA levels were inversely correlated with income in men. In children, the percentage DOM-1 positive samples were much higher compared to adults, 76 and 8% respectively, indicating a higher capacity to detoxify DON. The small sample size among children made it difficult to study associations between urine mycotoxins levels and food group intake. All PDI estimates [DON (with and without DOM-1), ZEA (with and without α-ZOL and β-ZOL) and FB1] were below the TDI values except for DON exposure in adults, as reported previously, 1.3% of the volunteers were above the TDI.

High-throughput method for ear phenotyping and kernel weight estimation in maize using ear digital imaging

BACKGROUND

Grain yield, ear and kernel attributes can assist to understand the performance of maize plant under different environmental conditions and can be used in the variety development process to address farmer's preferences. These parameters are however still laborious and expensive to measure.

RESULTS

A low-cost ear digital imaging method was developed that provides estimates of ear and kernel attributes i.e., ear number and size, kernel number and size as well as kernel weight from photos of ears harvested from field trial plots. The image processing method uses a script that runs in a batch mode on ImageJ; an open source software. Kernel weight was estimated using the total kernel number derived from the number of kernels visible on the image and the average kernel size. Data showed a good agreement in terms of accuracy and precision between ground truth measurements and data generated through image processing. Broad-sense heritability of the estimated parameters was in the range or higher than that for measured grain weight. Limitation of the method for kernel weight estimation is discussed.

CONCLUSION

The method developed in this work provides an opportunity to significantly reduce the cost of selection in the breeding process, especially for resource constrained crop improvement programs and can be used to learn more about the genetic bases of grain yield determinants.

Experimental mould growth and mycotoxin diffusion in different food items

Isolates of Penicillium commune, Penicillium crustosum, Penicillium expansum, Penicillium roqueforti and Aspergillus versicolor, were inoculated on different food items (hard cheese, crème fraiche, tomato purée, apple and blueberry jam) and incubated at 15 °C for 14 days at 50% relative humidity (RH). After incubation the food samples were divided into 3 subsamples; A was 0-2 cm from the surface and including the fungal colony, subsample B was 2-4 cm and subsample C was the rest from >4 cm from the surface. The subsamples were analysed with a multianalyte method capable of identifying more than several hundreds of fungal metabolites. The outcome showed that mouldy food can contain a cocktail of bioactive secondary metabolites including mycotoxins and sometimes at high concentrations. Measurements of the diffusion of fungal metabolites from the colony on the surface (layer A) into the food (layer B and C) showed that the fungal metabolites do not diffuse more than 2 cm into the inner core of the hard cheese. On the other hand in more liquid foods, such as crème fraiche, fruit jams and tomato purée, the toxins diffused quite readily throughout the entire food sample. The levels of patulin found in the apple jam indicate that the tolerable daily intake for patulin may easily be exceeded even if the mouldy layer A is removed. This limited study calls for more similar studies to be performed to give risk managers a sound basis for advice to consumers.

Total hip arthroplasty following failure of core decompression and tantalum rod implantation

AIMS

One method of femoral head preservation following avascular necrosis (AVN) is core decompression and insertion of a tantalum rod. However, there may be a high failure rate associated with this procedure. The purpose of this study was to document the clinical and radiological outcomes following total hip arthroplasty (THA) subsequent to failed tantalum rod insertion.

PATIENTS AND METHODS

A total of 37 failed tantalum rods requiring total hip arthroplasty were identified from a prospective database. There were 21 hips in 21 patients (12 men and nine women, mean age 37 years, 18 to 53) meeting minimum two year clinical and radiographic follow-up whose THAs were carried out between November 2002 and April 2013 (mean time between tantalum rod implantation and conversion to a THA was 26 months, 6 to 72). These were matched by age and gender to individuals (12 men, nine women, mean age 40 years, 18 to 58) receiving THA for AVN without prior tantalum rod insertion.

RESULTS

There were no functional outcome differences between the two groups. Tantalum residue was identified on all post-operative radiographs in the tantalum group. Linear wear rates were comparable between groups with no evidence of catastrophic wear in either group.

CONCLUSION

In the short term, tantalum rod implantation does not demonstrate an adverse effect on subsequent total joint replacement surgery. There is however, a high rate of retained tantalum debris on post-operative radiographs and thus there is an unknown risk of accelerated articular wear necessitating longer term study. Cite this article: Bone Joint J 2016;98-B:1175-9.

Genetic structure of West Greenland populations of lumpfish Cyclopterus lumpus

In this study, 11 microsatellite markers were used to determine the structure of West Greenlandic lumpfish Cyclopterus lumpus populations across six spawning locations spanning >1500 km and compared with neighbouring populations in Canada and Iceland. To evaluate whether data allow for identification of origin of C. lumpus in Greenlandic waters, genetic assignment analysis was performed for 86 C. lumpus sampled on a feeding migration. Significant structuring with isolation by distance was observed in the West Greenland samples and two major subpopulations, north and south, were suggested. Based on F_ST values, closer relationships were observed between Greenland and Canada, than Greenland and Iceland. Surprisingly, the North Greenland population showed more similarities with Canadian samples, than did the geographically closer south-west Greenland population. Origin could be assigned for a high proportion of non-spawning fish and demonstrated a marked east-west spatial separation of fish of Greenlandic and Icelandic genotypes.

Unmanned aerial platform-based multi-spectral imaging for field phenotyping of maize

BACKGROUND

Recent developments in unmanned aerial platforms (UAP) have provided research opportunities in assessing land allocation and crop physiological traits, including response to abiotic and biotic stresses. UAP-based remote sensing can be used to rapidly and cost-effectively phenotype large numbers of plots and field trials in a dynamic way using time series. This is anticipated to have tremendous implications for progress in crop genetic improvement.

RESULTS

We present the use of a UAP equipped with sensors for multispectral imaging in spatial field variability assessment and phenotyping for low-nitrogen (low-N) stress tolerance in maize. Multispectral aerial images were used to (1) characterize experimental fields for spatial soil-nitrogen variability and (2) derive indices for crop performance under low-N stress. Overall, results showed that the aerial platform enables to effectively characterize spatial field variation and assess crop performance under low-N stress. The Normalized Difference Vegetation Index (NDVI) data derived from spectral imaging presented a strong correlation with ground-measured NDVI, crop senescence index and grain yield.

CONCLUSION

This work suggests that the aerial sensing platform designed for phenotyping studies has the potential to effectively assist in crop genetic improvement against abiotic stresses like low-N provided that sensors have enough resolution for plot level data collection. Limitations and future potential uses are also discussed.

Anaesthesia-Related Haemodynamic Complications in Williams Syndrome Patients: A Review of One Institution's Experience

Williams syndrome is a genetic disorder associated with cardiac pathology, including supravalvular aortic stenosis and coronary artery stenosis. Sudden cardiac death has been reported in the perioperative period and attributed to cardiovascular pathology. In this retrospective audit, case note and anaesthetic records were reviewed for all confirmed Williams syndrome patients who had received an anaesthetic in our institution between July 1974 and November 2009. There were a total of 108 anaesthetics administered in 29 patients. Twelve of the anaesthetics (11.1%) were associated with cardiac complications including cardiac arrest in two cases (1.85%). Of the two cardiac arrests, one patient died within the first 24 hours postanaesthetic and the other patient survived, giving an overall mortality of 0.9% (3.4%). We conclude that Williams syndrome confers a significant anaesthetic risk, which should be recognised and considered by clinicians planning procedures requiring general anaesthesia.

Biomonitoring study of deoxynivalenol exposure and association with typical cereal consumption in Swedish adults

Deoxynivalenol (DON) is a mycotoxin of the trichothecene family commonly found in cereals infested with different Fusarium species. DON acts primarily on the gastrointestinal and immune system and is suspected to be an underlying agent causing several outbreaks of gastrointestinal disorder among humans, which prompts studies of human exposure and estimations of intake among populations. However, assessing human exposure to mycotoxins is associated with several difficulties. Therefore, a study was undertaken among adults (18-80 years) in a subgroup of Riksmaten, the Swedish national survey investigating dietary habits, examining both the association between urinary DON concentration and dietary intake of cereals, and estimations of daily DON intake. The results indicate that exposure to DON is common among Swedish adults, as this mycotoxin was detected in 292 out of 326 urine samples (90%) at levels ranging from non-detectable to 65.8 ng DON/ml urine with a median level of 2.9 ng/ml. Furthermore, urinary DON (ng/mg creatinine) was associated with intake (g/day) of total cereal grain as well as whole grain. Urinary DON was also significantly associated with breakfast cereals and porridge consumption (P<0.05). Estimated DON intake in this study ranged between 2.5 and 5,443 ng/kg body weight (bw). 1% of the individuals had estimated intakes above the group provisional maximum tolerable daily intake (PMTDI; 1 μg/kg), whereas the mean and median intakes of 159 and 84 ng DON/kg bw, respectively, were considerably below the PMTDI. Along with the toxicological profile of DON, no serious health implications are to be expected for the majority of Swedish adults, although a potential health concern remains for some high cereal consumers. In conclusion, biomonitoring could prove to be a valuable tool for observing DON exposure among populations.

Perspectives on the development of antioxidant antiepileptogenic agents

Epilepsy is a chronic disorder of abnormal electrical activity in the brain characterized by recurrent unprovoked seizures. Currently used pharmaceutical agents do not treat the underlying disease process, and a significant proportion of epileptic patients are refractory to current therapies. Therefore there is a strong need for additional therapeutic agents, especially those that address the underlying disease process of epileptogenesis. The redox potential of cells is maintained by an appropriate balance between pro- and anti-oxidative molecules; oxidative stress and increases in toxic reactive oxygen species occur when this balance shifts towards oxidation. Neural tissues are especially sensitive to oxygen levels, and oxidative stress is thought to be involved in epileptogenesis. Increases in reactive oxygen species occur in response to sustained neuronal electrical activity and seizures. Therefore antioxidants have been suggested as therapeutic design strategies for the treatment and modulation of epilepsy. This minireview focuses on several key antioxidants and agents involved in defending against oxidative stress that may be targets for new antiepileptogenic drug design, including directacting antioxidants, Nrf2-activating agents, and prolyl-4-hydroxylase inhibitors. A description of the necessary physicochemical properties and a summary of animal models that are thought to be useful for developing antiepileptogenic agents are presented.

Real-time PCR detection of Fusarium species in Swedish oats and correlation to T-2 and HT-2 toxin content

Contamination of Fusarium moulds and subsequent production of mycotoxins is a common problem in cereals grown in Northern Europe. Oats is the third most important cereal crop in Sweden and is commonly contaminated by Fusarium. To date there are no published reports on the distribution of trichothecene-producing Fusaria in Swedish oats and correlation to T-2 and HT-2, the two most dominant toxins. Identification of Fusarium species by traditional methods requires specific skill and experience and quantification of specific species is not possible. Using modern molecular methods such as real-time PCR both identification and quantification of specific Fusarium species are possible directly from the food or feed samples. In this study, specific methods for Fusarium langsethiae, Fusarium sporotrichioides, Fusarium graminearum, Fusarium culmorum and Fusarium poae as well as for the total amount of DNA from trichothecene-producing species were evaluated with respect to precision, robustness and efficiency and then used in the analysis of oat samples. Sixty-two oat samples were taken from field trial harvests from 2006-2008 in the central and southern parts of Sweden and analysed for the presence of Fusarium species by using species-specific real-time PCR-based methods with TaqMan or SYBR Green biochemistry. The T-2 and HT-2 toxin content was analysed by gas chromatography with electron capture detection of the toxins' pentafluoropropyl derivatives. The results showed that F. langsethiae and F. poae were the most dominant Fusarium species among those tested in Swedish oats during this period. The DNA level of F. langsethiae correlated well with the level of T-2 and HT-2 toxin (r=0.7), indicating that this species was the most important producer of T-2 and HT-2 toxins in Swedish oats during the sampling period (2006 to 2008). It can also be concluded that real-time PCR is a powerful tool when studying Fusarium species distribution in oats.

Imageless computer navigation without pre-operative templating may lead to malpreparation of the femoral head in hip resurfacing

The computed neck-shaft angle and the size of the femoral component were recorded in 100 consecutive hip resurfacings using imageless computer-navigation and compared with the angle measured before operation and with actual component implanted. The reliability of the registration was further analysed using ten cadaver femora. The mean absolute difference between the measured and navigated neck-shaft angle was 16.3° (0° to 52°). Navigation underestimated the measured neck-shaft angle in 38 patients and the correct implant size in 11. Registration of the cadaver femora tended to overestimate the correct implant size and provided a low level of repeatability in computing the neck-shaft angle.

Prudent pre-operative planning is advisable for use in conjunction with imageless navigation since misleading information may be registered intraoperatively, which could lead to inappropriate sizing and positioning of the femoral component in hip resurfacing.

Imageless computer navigation for placement of the femoral component in resurfacing arthroplasty of the hip

We have investigated the accuracy of placement of the femoral component using imageless navigation in 100 consecutive Birmingham Hip Resurfacings. Pre-operative templating determined the native neck-shaft angle and planned stem-shaft angle of the implant. The latter were verified post-operatively using digital anteroposterior unilateral radiographs of the hip. The mean neck-shaft angle determined before operation was 132.7 degrees (118 degrees to 160 degrees ). The mean planned stem-shaft angle was a relative valgus alignment of 9.7 degrees (SD 2.6). The stem-shaft angle after operation differed from that planned by a mean of 2.8 degrees (SD 2.0) and in 86% of cases the final angle measured within +/- 5 degrees of that planned. We had no instances of notching of the neck or varus alignment of the implant in our series. A learning curve was observed in the time taken for navigation, but not for accurate placement of the implant. Navigation in hip resurfacing may afford the surgeon a reliable and accurate method of placement of the femoral component.

Cancellous bone screw purchase: A comparison of synthetic femurs, human femurs, and finite element analysis

Biomechanical assessments of orthopaedic fracture fixation constructs are increasingly using commercially available analogues such as the fourth-generation composite femur (4GCF). The aim of this study was to compare cancellous screw purchase directly between these surrogates and human femurs, which has not been done previously. Synthetic and human femurs each had one orthopaedic cancellous screw (major diameter, 6.5 mm) inserted along the femoral neck axis and into the spongy bone of the femoral head to a depth of 30 mm. Screws were removed to obtain pull-out force, shear stress, and energy values. The three experimental study groups ( n = 6 femurs each) were the 4GCF with a ‘solid’ cancellous matrix, the 4GCF with a ‘cellular’ cancellous matrix, and human femurs. Moreover, a finite element model was developed on the basis of the material properties and anatomical geometry of the two synthetic femurs in order to assess cancellous screw purchase. The results for force, shear stress, and energy respectively were as follows: 4GCF solid femurs, 926.47 ± 66.76 N, 2.84 ± 0.20 MPa, and 0.57 ± 0.04 J; 4GCF cellular femurs, 1409.64 ± 133.36 N, 4.31 ± 0.41 MPa, and 0.99 ± 0.13 J; human femurs, 1523.29 ± 1380.15 N, 4.66 ± 4.22 MPa, and 2.78 ± 3.61 J. No statistical differences were noted when comparing the three experimental groups for pull-out force ( p = 0.413), shear stress ( p = 0.412), or energy ( p = 0.185). The 4GCF with either a ‘solid’ or ‘cellular’ cancellous matrix is a good biomechanical analogue to the human femur at the screw thread—bone interface. This is the first study to perform a three-way investigation of cancellous screw purchase using 4GCFs, human femurs, and finite element analysis.

Femoral neck fracture following hip resurfacing

A total of 20 pairs of fresh-frozen cadaver femurs were assigned to four alignment groups consisting of relative varus (10° and 20°) and relative valgus (10° and 20°), 75 composite femurs of two neck geometries were also used. In both the cadaver and the composite femurs, placing the component in 20° of valgus resulted in a significant increase in load to failure. Placing the component in 10° of valgus had no appreciable effect on increasing the load to failure except in the composite femurs with varus native femoral necks. Specimens in 10° of varus were significantly weaker than the neutrally-aligned specimens.

The results suggest that retention of the intact proximal femoral strength occurs at an implant angulation of ≥ 142°. However, the benefit of extreme valgus alignment may be outweighed in clinical practice by the risk of superior femoral neck notching, which was avoided in this study.

A biomechanical assessment of the coupling of torsion and tension in the human scapholunate ligament

The mechanical behaviour of human scapholunate ligaments is not well described in the literature with regard to torsion. In this study, intact scapholunate specimens were mechanically tested in torsion to determine whether a simultaneous tensile load was generated. Human intact scapholunate specimens ( n = 19) were harvested. The scaphoid and lunate bones were potted in square chambers using epoxy cement, while the interposing ligament remained exposed. Each specimen was mounted rigidly in a specially designed test jig and remained at a fixed axial length during all tests. Specimens were subjected to a torsional load regime that included cyclic preconditioning, ramp-up, stress relaxation, ramp-down, rest, and torsion to failure. Torque and axial tension were monitored simultaneously. The relationship between torsion and tension was determined. Graphs of torque versus tension were generated, from which outcome measures were extracted. Tests demonstrated a clear relationship between applied torsion and the resulting generation of tension for the ligament during ramp-up (torsion-to-tension ratio, 38.86 ± 29.00 mm; linearity coefficient R2 = 0.89 ± 0.15; n = 19), stress relaxation (torsion-to-tension ratio, 23.43 ± 15.84 mm; R2 = 0.90 ± 0.09; n = 16), and failure tests (torsion-to-tension ratio, 38.81 ± 26.39 mm; R2 = 0.77 ± 0.20; n = 16). No statistically significant differences were detected between the torsion-to-tension ratios ( p = 0.13) or between the linearity ( R2) of the best-fit lines ( p > 0.085). A strongly coupled linear relationship between torsion and tension for the scapholunate ligament was exhibited in all test phases. This may suggest interplay between these two parameters in the stabilization of the ligament during normal motion and for injury cascades.