Measuring the visual angle of polarization-related entoptic phenomena using structured light

The ability to perceive polarization-related entoptic phenomena arises from the dichroism of macular pigments held in Henle's fiber layer of the retina and can be inhibited by retinal diseases, such as age-related macular degeneration, which alters the structure of the macula. Structured light tools enable the direct probing of macular pigment density and retinal structure through the perception of polarization-dependent entoptic patterns. Here, we directly measure the visual angle of an entoptic pattern created through the illumination of the retina with a structured state of light and a perception task that is insensitive to corneal birefringence. The central region of the structured light stimuli was obstructed, with the size of the obstruction varying according to a psychophysical staircase. Two stimuli, one producing 11 azimuthal fringes and the other three azimuthal fringes, were presented to 24 healthy participants. The pattern with 11 azimuthal fringes produced an average visual angle threshold of 10° ± 1° and a 95% confidence interval (C.I.) of [6°, 14°]. For the pattern with three azimuthal fringes, a threshold extent of 3.6° ± 0.3° C.I. = [1.3°, 5.8°] was measured, a value similar to the published extent of Haidinger's brush (4°). The increase in apparent size and clarity of entoptic phenomena produced by the presented structured light stimuli offers the potential to detect the early signs of macular disease over perception tasks using uniform polarization stimuli.

Effects of visual span on Chinese reading performance in normal peripheral vision

The current study examined the relationships among temporal processing speed, spatial visual span and Chinese character reading speed in normal central and peripheral vision. Maximum reading speed (MRS) and critical print size (CPS) of 26 native Chinese readers (13 young and 13 older adults) were determined at three visual field locations: central vision, 10° left and 10° below fixation using a rapid serial visual presentation (RSVP) task. Temporal processing speed was measured using trigrams of randomly selected Chinese characters presented at a range of exposure durations, while spatial visual span was measured using trigrams presented at different spatial positions. It was found that shorter temporal processing speed and larger spatial visual span were associated with faster MRS at the central and inferior visual field locations, but not at the left of fixation location. As expected, reading and visual span metrics were better in central vision compared to both peripheral locations. In addition, reading, temporal processing, and spatial visual span metrics were better in the young than older subjects (except for similar temporal processing speed at two peripheral locations). The results for central and inferior presentation locations support the hypothesis that temporal processing speed and spatial visual span were associated with Chinese character reading speed. Surprisingly, no correlation was observed for the 10° left of the fixation location, suggesting that the factors affecting reading speed might differ for inferior and lateral peripheral viewing locations.

Measurement properties of the WHO Disability Assessment Schedule 2.0 for evaluating functional status after inpatient surgery

BACKGROUND

Expert recommendations propose the WHO Disability Assessment Schedule (WHODAS) 2.0 as a core outcome measure in surgical studies, yet data on its long-term measurement properties remain limited. These were evaluated in a secondary analysis of the Measurement of Exercise Tolerance before Surgery (METS) prospective cohort.

METHODS

Participants were adults (40 years of age or older) who underwent inpatient non-cardiac surgery. The 12-item WHODAS and EQ-5DTM-3L questionnaires were administered preoperatively (in person) and 1 year postoperatively (by telephone). Responsiveness was characterized using standardized response means (SRMs) and correlation coefficients between change scores. Construct validity was evaluated using correlation coefficients between 1-year scores and comparisons of WHODAS scores across clinically relevant subgroups.

RESULTS

The analysis included 546 patients. There was moderate correlation between changes in WHODAS and various EQ-5DTM subscales. The strongest correlation was between changes in WHODAS and changes in the functional domains of the EQ-5D-3L-for example, mobility (Spearman's rho 0.40, 95 per cent confidence interval [c.i.] 0.32 to 0.48) and usual activities (rho 0.45, 95 per cent c.i. 0.30 to 0.52). When compared across quartiles of EQ-5D index change, median WHODAS scores followed expected patterns of change. In subgroups with expected functional status changes, the WHODAS SRMs ranged from 'small' to 'large' in the expected directions of change. At 1 year, the WHODAS demonstrated convergence with the EQ-5D-3L functional domains, and good discrimination between patients with expected differences in functional status.

CONCLUSION

The WHODAS questionnaire has construct validity and responsiveness as a measure of functional status at 1 year after major surgery.

Evaluation of prognostic risk models for postoperative pulmonary complications in adult patients undergoing major abdominal surgery: a systematic review and international external validation cohort study

BACKGROUND

Stratifying risk of postoperative pulmonary complications after major abdominal surgery allows clinicians to modify risk through targeted interventions and enhanced monitoring. In this study, we aimed to identify and validate prognostic models against a new consensus definition of postoperative pulmonary complications.

METHODS

We did a systematic review and international external validation cohort study. The systematic review was done in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched MEDLINE and Embase on March 1, 2020, for articles published in English that reported on risk prediction models for postoperative pulmonary complications following abdominal surgery. External validation of existing models was done within a prospective international cohort study of adult patients (≥18 years) undergoing major abdominal surgery. Data were collected between Jan 1, 2019, and April 30, 2019, in the UK, Ireland, and Australia. Discriminative ability and prognostic accuracy summary statistics were compared between models for the 30-day postoperative pulmonary complication rate as defined by the Standardised Endpoints in Perioperative Medicine Core Outcome Measures in Perioperative and Anaesthetic Care (StEP-COMPAC). Model performance was compared using the area under the receiver operating characteristic curve (AUROCC).

FINDINGS

In total, we identified 2903 records from our literature search; of which, 2514 (86·6%) unique records were screened, 121 (4·8%) of 2514 full texts were assessed for eligibility, and 29 unique prognostic models were identified. Nine (31·0%) of 29 models had score development reported only, 19 (65·5%) had undergone internal validation, and only four (13·8%) had been externally validated. Data to validate six eligible models were collected in the international external validation cohort study. Data from 11 591 patients were available, with an overall postoperative pulmonary complication rate of 7·8% (n=903). None of the six models showed good discrimination (defined as AUROCC ≥0·70) for identifying postoperative pulmonary complications, with the Assess Respiratory Risk in Surgical Patients in Catalonia score showing the best discrimination (AUROCC 0·700 [95% CI 0·683-0·717]).

INTERPRETATION

In the pre-COVID-19 pandemic data, variability in the risk of pulmonary complications (StEP-COMPAC definition) following major abdominal surgery was poorly described by existing prognostication tools. To improve surgical safety during the COVID-19 pandemic recovery and beyond, novel risk stratification tools are required.

FUNDING

British Journal of Surgery Society.

AB1209 MECHANISTIC FACTORS CONTRIBUTING TO PAIN AND FATIGUE IN FIBROMYALGIA AND ME/CFS: AUTONOMIC AND INFLAMMATORY INSIGHTS FROM AN EXPERIMENTAL MEDICINE STUDY

Background

Fibromyalgia and ME/CFS are multifaceted conditions with overlapping symptoms(1); the pathoaetiological mechanisms are complex and debated(2), however there is a strong association with features of hereditary disorders of connective tissue (hypermobility) and autonomic and inflammatory abnormalities (1,2).

Objectives

To determine potential autonomic and inflammatory mechanisms of pain and fatigue in fibromyalgia and ME/CFS

Methods

After excluding participants with WCC higher than 10 (suggesting acute infection) baseline markers of inflammation (CRP and ESR) were available for 60 patients with confirmed diagnoses of Fibromyalgia and/ or ME/CFS and 23 matched controls. Participants then underwent full research diagnostic evaluation including a hypermobility assessment(1) and autonomic challenge (60 degree head up tilt, ISRCTN78820481). Subjective pain and fatigue were assessed before and after challenge (VAS). Linear regression models were used to explore predictors, with adjustment for confounders as appropriate. Mediation analyses (looking for mechanistic effects) were conducted according to the method of Hayes (3) and mediation considered significant if bootstrapped confidence intervals of the estimated indirect effect did not cross zero. In these mediation analyses predictor variable was group membership (patient or control), outcome variable was change in 1)pain and 2)fatigue induced by challenge and mediatiors 1)no of connective tissue features in hypermobility diagnostic criteria endorsed by participant; 2)baseline inflammatory markers.

Results

ESR and CRP were significantly higher in patients rather than controls, even after correcting for BMI, age and sex (B=5.15, t=2.05, p=0.044; B=1.77, t=2.15, p=0.044 respectively). Adjusted ESR and CRP correlated with both subjective fatigue (B=0.44, t=2.09, p=0.04; B=1.63, t=2.60, p=0.011) and pain severity (B=0.13, t=2.51, p=0.014; B=0.45, t=3.01, p=0.004) at baseline. Autonomic challenge amplified pain (B=14.20, t=2.87, p=0.005) and fatigue (B=31.48, t=5.95, p=<0.001) in patients to a significantly greater degree than controls, controlling for baseline levels. Baseline ESR and CRP also predicted challenge-induced increase in fatigue (B=0.78, t=370, p=<0.001; B=1.91, t=3.36, p=<0.001) and ESR challenge-induced increases in pain (B=0.46, t=2.35, p=0.021).

Mediation analysis demonstrated that number of connective tissue features expressed in hypermobility criteria mediated the degree to which subjective pain was increased by the autonomic challenge (Bootstraped 95% CI of indirect effect do not cross zero, 0.1572 – 6.8171). ESR mediated the degree to which subjective fatigue was increased by the autonomic challenge (Bootstraped 95% CI of indirect effect do not cross zero,0.7541 – 7.3888).

Conclusion

To our knowledge this is the first study to directly explore autonomic and inflammatory mechanisms of pain and fatigue in a combined population of Fibromyalgia and ME/CFS. This study this adds to the evidence-base of baseline inflammatory abnormalities in fibromyalgia and ME/CFS. It highlights their potential role in predicting symptom severity and their potential mechanistic role in autonomic induced pain and fatigue, suggesting future treatment strategies.

References

[1]Eccles JA, Thompson B, Themelis K, Amato ML, Stocks R, Pound A, et al. Beyond bones: The relevance of variants of connective tissue (hypermobility) to fibromyalgia, ME/CFS and controversies surrounding diagnostic classification: an observational study. Clin Med (Lond). 2021;21(1):53-8.

[2]Eccles JA, Davies KA. The challenges of chronic pain and fatigue. Clin Med (Lond). 2021;21(1):19-27.

[3]Hayes AF. Partial, conditional, and moderated moderated mediation: Quantification, inference, and interpretation. Commun Monogr. 2018;85(1):4-40.

Disclosure of Interests

Jessica Eccles: None declared, Charlotte Thompson: None declared, Beth Thompson: None declared, Marisa Amato: None declared, Kristy Themelis: None declared, Hugo Critchley: None declared, Neil Harrison Grant/research support from: speakers bureau, Kevin Davies: None declared

Complex cognitive algorithms preserved by selective social learning in experimental populations

Many human abilities rely on cognitive algorithms discovered by previous generations. Cultural accumulation of innovative algorithms is hard to explain because complex concepts are difficult to pass on. We found that selective social learning preserved rare discoveries of exceptional algorithms in a large experimental simulation of cultural evolution. Participants (N = 3450) faced a difficult sequential decision problem (sorting an unknown sequence of numbers) and transmitted solutions across 12 generations in 20 populations. Several known sorting algorithms were discovered. Complex algorithms persisted when participants could choose who to learn from but frequently became extinct in populations lacking this selection process, converging on highly transmissible lower-performance algorithms. These results provide experimental evidence for hypothesized links between sociality and cognitive function in humans.

Human psychophysical discrimination of spatially dependant Pancharatnam-Berry phases in optical spin-orbit states

We tested the ability of human observers to discriminate distinct profiles of spatially dependant geometric phases when directly viewing stationary structured light beams. Participants viewed polarization coupled orbital angular momentum (OAM) states, or "spin-orbit" states, in which the OAM was induced through Pancharatnam-Berry phases. The coupling between polarization and OAM in these beams manifests as spatially dependant polarization. Regions of uniform polarization are perceived as specifically oriented Haidinger's brushes, and study participants discriminated between two spin-orbit states based on the rotational symmetry in the spatial orientations of these brushes. Participants used self-generated eye movements to prevent adaptation to the visual stimuli. After initial training, the participants were able to correctly discriminate between two spin-orbit states, differentiated by OAM [Formula: see text], with an average success probability of [Formula: see text] ([Formula: see text], [Formula: see text]). These results support our previous observation that human observers can directly perceive spin-orbit states, and extend this finding to non-rotating beams, OAM modes induced via Pancharatnam-Berry phases, and the discrimination of states that are differentiated by OAM.

A decision support tool for the detection of pancreatic cancer in general practice: A modified Delphi consensus

BACKGROUND/OBJECTIVES

Diagnosis of pancreatic cancer is often delayed, contributing to patient and family distress and leading to worse survival. We aimed to develop a decision support tool to support primary care providers to identify patients that should undergo investigations for pancreatic cancer, and to recommend initial diagnostic pathways.

METHODS

A modified Delphi process, including a series of three surveys, was undertaken to ascertain clinical expert opinion on which combinations of signs, symptoms and risk factors should be included in a tool for the early identification of pancreatic cancer. A group of clinical specialists finalised the development of the tool during a focus group meeting.

RESULTS

The tool presents individual or combinations of signs, symptoms, and risk factors in three tiers which direct the urgency of investigation. Tier 1 includes 5 clinical presentation and risk factors clusters that indicate the need for urgent investigation of the pancreas. A further five clusters are included as Tier 2 aiming to elimate other causes and reduce the time to investigating the pancreas. Tier 3 includes a list of non-specific signs, symptoms and risk factors that indicate the need to consider pancreatic cancer as a potential diagnosis, but without specific recommendations for investigation.

CONCLUSIONS

Prospective validation studies are now required prior to implementation in the primary care setting. Implementation into primary care practice and as an educational resource may facilitate rapid diagnosis and improve outcomes such as distress and survival.

Factors influencing aspirations for practice ownership by veterinary professional students at the University of Sydney

Understanding the factors that influence the aspirations of future veterinary practitioners is critical to assist succession planning. The aim of this study was to discover factors that currently influence veterinary students' desire to own a veterinary practice in the future, including whether these aspirations were influenced by a student's experience throughout their years of veterinary studies. The study surveyed University of Sydney students enrolled in the postgraduate Doctor of Veterinary Medicine (DVM) degree in 2020. A response rate of 29% was obtained (142/508). Of those 142 respondents, 50 (35%) indicated that they wished to own a practice in the future, 40 (28%) indicated that they did not wish to own a practice in the future and 52 (37%) were unsure. The results demonstrate that practice ownership is currently only influenced by factors that are external to a student's experience at university, given that there was no significant difference between practice ownership aspirations between DVM years. After excluding those who were unsure, veterinary students whose parents or guardians own, or have owned, a business are three times more likely (OR = 3.19; 95% CI = 1.35-7.73; P < 0.01) to aspire to practice ownership than those students whose parents have not. Asian students showed significantly less interest in practice ownership than Caucasian students (OR = 0.41; 95% CI = 0.16-0.99, P < 0.05). Further qualitative research is required to better understand these findings so that tailored advice can be provided to students and veterinary schools to positively support graduating veterinary professionals towards future practice ownership.

COVID-19 infection in ethnic minorities: A systematic review of age and gender distribution

Background

Currently, there have been 135,646,617 cases of COVID-19 infection and 2,930,732 deaths in the world. Compared with the White populations, members of the ethnic minorities living in Europe and North America are disproportionately diagnosed, hospitalized and dying from COVID-19. The reasons for this relatively increased risk of infection and adverse outcome are poorly understood. The aim of this review is to summarise current epidemiological evidence on age and gender distribution in ethnic minority patients hospitalized with COVID-19 infection.

Methods

Multiple electronic databases were searched. Data from studies, published in any language, reporting the risk factors, incidence and outcomes of COVID-19 infection in hospitalized White and ethnic minorities patients were extracted, reviewed and compiled.

Results

36 studies reporting data on age and 26 on gender were included in the review. Ethnic minority patients hospitalized with COVID-19 were relatively younger than White patients. Within the different minority groups, a greater proportion of Black patients were female, whereas a greater proportion of Asian patients were male.

Conclusions

This review confirms findings from individual studies that with regard to age, the ethnic minority patients hospitalized with COVID-19 infection are relatively younger than the White patients. There is also a disparity with regard to gender within the different minority groups.

Key messages

There is a disparity with regard to age and gender between the different ethnic groups affected with COVID-19 infection in Europe and North America. Potential factors for disparities are genetics, vitamin D deficiency, BCG vaccine, comorbidities, occupation, social gradient, housing, PPE access and understanding/compliance to protection measures.

OP0078 HIGH MEDIAN NERVE LESION SECONDARY TO SEVERE GIANT CELL ARTERITIS (GCA)

Background:

Giant cell arteritis (GCA) is a systemic vasculitis affecting large to medium-sized vessels. Cranial nerve lesions are frequently documented secondary to GCA, however peripheral nerves are rarely involved.

Objectives:

We present an unusual case of a GCA-associated isolated high median nerve palsy.

Methods:

Case report.

Results:

A 76 year old white British female presented in Spain with three weeks of frontotemporal headaches, mandibular claudication, photopsia and constitutional symptoms, followed by acute-onset right hand paresis and dysaesthesia. Acute-phase reactants were elevated. COVID-19 PCR was negative. Shortly after admission she developed acute bilateral anterior ischaemic optic neuropathy and tongue necrosis with autoamputation. Temporal artery ultrasound and biopsy confirmed GCA. PET-CT showed no evidence of a diffuse large-vessel vasculitis. She was repatriated to the UK for ongoing inpatient care. Upper limb neurophysiology two months later demonstrated an isolated right high median nerve lesion, with reduced median motor responses and absent sensory responses with denervation in extensor carpi radialis. Imaging excluded a central lesion. The timing of her symptoms suggested the lesion was secondary to GCA. Treatment was with tocilizumab, methotrexate and tapering corticosteroids, alongside PEG feeding and careful multi-disciplinary rehabilitation.

Conclusion:

We suggest there are two important learning points from this complex case. Firstly, peripheral nerve lesions can occur in GCA, although they are rare. A literature search identified a modest number of case reports of brachial plexus or lower cervical nerve lesions1,2. Neurologic manifestations in GCA are attributed to vasculitis of the vasa nervorum, or extension of inflammation from arteries to contiguous nerves1,2. The restriction of clinical involvement to the median nerve alone would appear to favour the former mechanism. Functional recovery of neurological deficits is typically partial at best.

Secondly, this case highlights the difficulty faced by clinicians in recognising GCA and the importance of urgent treatment with glucocorticoids. The patient developed GCA during the ongoing COVID-19 pandemic when Spain was the second-worst affected European country (5% seroprevalence; 95% CI 4.7-5.4)3. The partial overlap in symptoms between GCA and COVID-19 (e.g. headache, pyrexia, malaise, elevated acute-phase reactants) can cause diagnostic confusion and treatment delay4. GCA should be considered in the differential diagnosis of older patients with suspected COVID-19, or the non-specifically unwell elderly patient.

References:

[1]Blaise S, et al. Horton’s disease revealed by brachial C5 plexopathy [French]. Rev Med Interne. 2005;26(7):578-82.

[2]Merianos P, et al. Giant cell arteritis of the median nerve simulating carpal tunnel syndrome. Hand. 1983;15(3): 249-251.

[3]Pollán M, et al. Prevalence of SARS-CoV-2 in Spain (ENE-COVID): a nationwide, population-based seroepidemiological study. Lancet. 2020; 396(10250): 535-544.

[4]Monti S, Delvino P, et al. Impact of delayed diagnoses at the time of COVID-19: increased rate of preventable bilateral blindness in giant cell arteritis. Ann Rheum Dis. 2020;79:1658-1659.

Table 1.Area/movementResultAbductor pollicis brevisGrade 2 weaknessOpponens pollicisGrade 4 weaknessPronator teres/quadratusGrade 4 weaknessFlexor pollicis longusGrade 1-2 weaknessFlexor digitorum profundus (digit 2 and 3)Grade 1-2 weaknessFinger abductionPreservedFinger extensionPreservedOther commentsDysaesthesia in distribution of median nerve

Disclosure of Interests:

Kundan Iqbal: None declared, James Miller Speakers bureau: Dr Miller has participated in pharmaceutical-sponsored symposiums previously but not in last five years., Consultant of: Dr Miller has participated in pharmaceutical-sponsored consultancy previously but not in last five years., Ming Lai: None declared, Mia Charnley: None declared, Muhammad Meraj: None declared, Ben Thompson Speakers bureau: Dr Thompson has participated in educational talks for Roche, Novartis, Lilly and UCB., Consultant of: Dr Thompson has participated in advisory boards for Roche, Novartis, Lilly, Gilead, Abbvie and UCB.

SAT0272 THE VALUE OF CLINICAL AND LABORATORY FEATURES TO PREDICT EXTENT OF LARGE VESSEL VASCULITIS ON PET CT

Background:

Giant cell arteritis (GCA) is an idiopathic vasculitis affecting large and medium-sized vessels. The pattern of arterial involvement is heterogeneous with two overlapping categories recognised: classical cranial GCA and extra-cranial GCA (or large vessel vasculitis – LVV) that predominantly affects the aorta and its proximal branches. Although LVV is present in around 80% of patients with cranial GCA, and around one third will develop large vessel complications, there are no guidelines for which patients should be screened for it (1). We sought to investigate whether clinical and laboratory features were a useful guide to the severity of LVV on FDG PET-CT.

Objectives:

To retrospectively analyse whether baseline patient characteristics are able to predict the extent of large vessel vasculitis on PET-CT.

Methods:

Clinical data for 65 patients referred for a PET-CT scan by Rheumatology at the Freeman Hospital, Newcastle between January 2015 and May 2018 were retrospectively analysed. The most recent full blood count and inflammatory markers prior to the scan were used. Scans were reviewed by a consultant radiologist and trainee. The arterial network was split in to ten potentially involved territories (aortic arch, thoracic aorta, abdominal aorta, iliac vessels, axillary, brachiocephalic, subclavian, carotid, vertebral and femoral arteries. Both the value of highest standardised uptake value (SUV max) and the territory affected was recorded for each positive scan.

Results:

In the period analysed 65 PET-CT scans were requested, mostly (77%) as baseline investigations for symptoms with LVV in the differential diagnosis. Of these 22 (34%) were positive for LVV and in that group the majority of patients (64%) were female. In those with a negative scan, 47.5% were on concurrent steroid treatment compared to 9% with a positive scan. Regression analysis suggested that the number of systemic features (weight loss, pyrexia, polymyalgia) was weakly correlated with the number of affected territories (p=0.04). In contrast there was no correlation between laboratory tests ((CRP (p=0.91), ESR (p=0.46), Hb (p=0.44), platelets (p=0.74)) and the number of territories affected. The aortic arch (47%) was most commonly the territory with the highest degree of FDG uptake (SUV max) followed by the abdominal aorta (21%) and thoracic (10%) and femoral arteries (10%). There was no correlation between SUV max and laboratory tests ((CRP (p=0.55), ESR (p=0.89), Hb (p=0.82), platelets (p=0.17)) or the number of systemic features (p=0.7). There was no significant difference in the number of territories affected between those on steroid treatment at the time of the scan and steroid-naïve patients, albeit the number of positive scans in those on steroid treatment was low (n=5).

Conclusion:

These results suggest that clinical and laboratory features are a poor guide to predicting the maximal severity and extent of disease on FDG PET-CT.

References:

[1]Koster MJ, Matteson EL, Warrington KJ. Large-vessel giant cell arteritis: diagnosis, monitoring and management. Rheumatology (Oxford). 2018;57(suppl_2):ii32-ii42.

Disclosure of Interests:

None declared

Psychosocial Adjustment to Age-related Macular Degeneration

This article reports on a study of the psychosocial adjustment to age-related macular degeneration of 30 elderly persons by comparing the responses of subjects with this condition to those from age- and sex-matched controls on four psychosocial scales: life satisfaction, daily hassles, social support, and self-esteem. The subjects with the condition reported significantly poorer life satisfaction and greater stress, perhaps as a result of poor social support.

Uptake of HDL-cholesterol contributes to lipid accumulation in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC), which accounts for the majority of kidney cancer, is known to accumulate excess cholesterol. However, the mechanism and functional significance of the lipid accumulation for development of the cancer remains obscure. In this study, we analyzed 42 primary ccRCC samples, and determined that cholesterol levels of ~ 70% of the tumors were at least two-fold higher than that of benign kidney tissues. Compared to tumors without cholesterol accumulation, those containing excess cholesterol expressed higher levels of scavenger receptor BI (SR-B1), a receptor for uptake of HDL-associated cholesterol, but not genes involved in cholesterol synthesis and uptake of LDL-associated cholesterol. To further determine the roles of sterol accumulation for cancer development, we implanted ccRCC from patients into mouse kidneys using a mouse ccRCC xenograft model. Feeding mice with probucol, a compound lowing HDL-cholesterol, markedly reduced levels of cholesterol in tumors containing excess cholesterol. This treatment, however, did not affect growth of these tumors. Our study suggests that cholesterol overaccumulation in ccRCC is the consequence of increased uptake of HDL-cholesterol as a result of SR-B1 overexpression, but the lipid accumulation by itself may not play a significant role in progression of the cancer.

A Type 1 Diabetes Genetic Risk Score Predicts Progression of Islet Autoimmunity and Development of Type 1 Diabetes in Individuals at Risk

OBJECTIVE

We tested the ability of a type 1 diabetes (T1D) genetic risk score (GRS) to predict progression of islet autoimmunity and T1D in at-risk individuals.

RESEARCH DESIGN AND METHODS

We studied the 1,244 TrialNet Pathway to Prevention study participants (T1D patients' relatives without diabetes and with one or more positive autoantibodies) who were genotyped with Illumina ImmunoChip (median [range] age at initial autoantibody determination 11.1 years [1.2-51.8], 48% male, 80.5% non-Hispanic white, median follow-up 5.4 years). Of 291 participants with a single positive autoantibody at screening, 157 converted to multiple autoantibody positivity and 55 developed diabetes. Of 953 participants with multiple positive autoantibodies at screening, 419 developed diabetes. We calculated the T1D GRS from 30 T1D-associated single nucleotide polymorphisms. We used multivariable Cox regression models, time-dependent receiver operating characteristic curves, and area under the curve (AUC) measures to evaluate prognostic utility of T1D GRS, age, sex, Diabetes Prevention Trial-Type 1 (DPT-1) Risk Score, positive autoantibody number or type, HLA DR3/DR4-DQ8 status, and race/ethnicity. We used recursive partitioning analyses to identify cut points in continuous variables.

RESULTS

Higher T1D GRS significantly increased the rate of progression to T1D adjusting for DPT-1 Risk Score, age, number of positive autoantibodies, sex, and ethnicity (hazard ratio [HR] 1.29 for a 0.05 increase, 95% CI 1.06-1.6; P = 0.011). Progression to T1D was best predicted by a combined model with GRS, number of positive autoantibodies, DPT-1 Risk Score, and age (7-year time-integrated AUC = 0.79, 5-year AUC = 0.73). Higher GRS was significantly associated with increased progression rate from single to multiple positive autoantibodies after adjusting for age, autoantibody type, ethnicity, and sex (HR 2.27 for GRS >0.295, 95% CI 1.47-3.51; P = 0.0002).

CONCLUSIONS

The T1D GRS independently predicts progression to T1D and improves prediction along T1D stages in autoantibody-positive relatives.

Contingency Training Alters Neurobiological Components of Emotional Resilience in Male and Female Rats

Prior research with a rat model of behavioral therapy [i.e., effort-based reward (EBR) contingency training] suggests that strengthened associations between physical effort and desired outcomes enhance neurobiological indices of resilience. In the current study, male and female Long-Evans rats were exposed to either six weeks of EBR training or noncontingent training prior to 10 days of exposure to chronic unpredictable stress (CUS). Subsequently, all animals were exposed to a problem-solving task and then trained in a spatial learning/foraging task, the Dry Land Maze (DLM). Following habituation training and test trials, rats were assessed in a probe trial that generated a prediction error (cognitive uncertainty). Results indicated that, during CUS exposure, contingency-training enhanced dehydroepiandrosterone/corticosterone ratios (consistent with healthier stress responses), especially in male rats. Additionally, contingency training increased exploratory behaviors in the probe trial as well as differentially influenced on-task problem-solving performance in males and females. Following the probe trial, brains were exposed to histological analyses to determine the effects of sex and contingency training on various neurobiological markers. Contingency training decreased BDNF-immunoreactivity (ir) in the hippocampus CA1 and lateral habenula, implicating differential neuroplasticity responses in the training groups. Further, coordinated fos-ir activation in areas associated with emotional resilience (i.e., motivation-regulation) was observed in contingent-trained animals. In sum, the current findings confirm that behavioral training is associated with neurobiological markers of emotional resilience; however, further assessments are necessary to more accurately determine the therapeutic potential for the EBR contingency training model.

Abstract TP212: 24 S -Hydroxycholesterol as a Serum Biomarker for Acute Stroke

Introduction: Several serum based biomarkers for acute stroke have been identified, but the clinical values of these biomarkers have not been realized due to inadequate sensitivity and specificity in their measurements. 24 S -Hydroxycholesterol is a stable metabolite of cholesterol synthesized by neurons of the CNS, and released to the serum at a constant rate.

Hypothesis: We hypothesized that serum 24 S -Hydroxycholesterol would be an ideal biomarker for acute stroke.

Methods: Acute stroke patients presenting to ED were enrolled after informed consent. Serum samples were collected in ED and levels of 24 S -Hydroxycholesterol were determined by mass spectrometry. We enrolled 63 patients from October 2015 to October 2016. Of these 63 patients, 60 presented within 8 hours from onset of symptoms. Patients were categorized as no stroke, ischemic stroke, and intracerebral hemorrhage. We compared serum 24 S -Hydroxycholesterol levels in each group and the variation in 24 S -Hydroxycholesterol levels with regard to presenting NIHSS.

Result: Out of the 63 patients enrolled, 22 did not have a stroke, 36 had ischemic stroke, and 5 had intracerebral hemorrhage. The mean 24 S -Hydroxycholesterol levels were 54 ng/ml, 58 ng/ml and 75 ng/ml in the no stroke group, ischemic stroke group and intracerebral hemorrhage group, respectively. No correlation was observed between NIHSS and 24 S -Hydroxycholesterol levels. Difference in 24 S -Hydroxycholesterol levels between no stroke and intracerebral hemorrhage patients was statistically significant, but was limited by the small sample size (P = 0.047).

Conclusion: 24 S -Hydroxycholesterol may be a useful serum biomarker for intracerebral hemorrhage. Analyses in a larger population is needed to determine the practical importance of this biomarker.

The Far Ultra-Violet imager on the ICON mission

ICON Far UltraViolet (FUV) imager contributes to the ICON science objectives by providing remote sensing measurements of the daytime and nighttime atmosphere/ionosphere. During sunlit atmospheric conditions, ICON FUV images the limb altitude profile in the shortwave (SW) band at 135.6 nm and the longwave (LW) band at 157 nm perpendicular to the satellite motion to retrieve the atmospheric O/N2 ratio. In conditions of atmospheric darkness, ICON FUV measures the 135.6 nm recombination emission of O+ ions used to compute the nighttime ionospheric altitude distribution. ICON Far UltraViolet (FUV) imager is a CzernyTurner design Spectrographic Imager with two exit slits and corresponding back imager cameras that produce two independent images in separate wavelength bands on two detectors. All observations will be processed as limb altitude profiles. In addition, the ionospheric 135.6 nm data will be processed as longitude and latitude spatial maps to obtain images of ion distributions around regions of equatorial spread F. The ICON FUV optic axis is pointed 20 degrees below local horizontal and has a steering mirror that allows the field of view to be steered up to 30 degrees forward and aft, to keep the local magnetic meridian in the field of view. The detectors are micro channel plate (MCP) intensified FUV tubes with the phosphor fiber-optically coupled to Charge Coupled Devices (CCDs). The dual stack MCP-s amplify the photoelectron signals to dominate the CCD noise and the rapidly scanned frames are co-added to digitally create 12-second integrated images. Digital on-board signal processing is used to compensate for geometric distortion and satellite motion and to achieve data compression. The instrument was originally aligned in visible light by using a special grating and visible cameras. Final alignment, functional and environmental testing and calibration were performed in a large vacuum chamber with a UV source. The test and calibration program showed that ICON FUV meets its design requirements and is ready to be launched on the ICON spacecraft.

Walking in the shoes of caregivers of children with obesity: supporting caregivers in paediatric weight management

To incorporate the perspectives and experiences of family caregivers of children with obesity, the KidFit Health and Wellness Clinic, a paediatric weight management programme, embedded feedback opportunities into various stages of programme development. Caregivers were eligible to participate if their children had completed initial 4-week group-based pilot programming or were currently receiving treatment in 10 or 12 week group-based programming. Data were collected through feedback session discussions, audio-recorded, transcribed verbatim and analysed thematically. In total, 6 caregivers participated in the pilot group feedback session and 32 caregivers participated in the structured group feedback sessions. Caregivers reported that healthy lifestyle strategies first communicated by clinic staff to children during group sessions provided expert validation and reinforcement when discussing similar messages at home. Caregivers reported feeling isolated and blamed for causing their children's obesity and appreciated the supportive forum that group-based programming provided for sharing experiences. Since experiences of blame and isolation can burden caregivers of children with obesity, paediatric weight management programmes might consider including peer support opportunities and discussion forums for ongoing social support in addition to education about lifestyle change.

Exclusive enteral nutrition provides an effective bridge to safer interval elective surgery for adults with Crohn's disease

BACKGROUND

Few studies have reported the systematic use of exclusive enteral nutrition in the perioperative setting.

AIM

To test the hypothesis that exclusive enteral nutrition provides a safe and effective bridge to surgery and reduces post-operative complications, in adult patients with Crohn's disease requiring urgent surgery for stricturing or penetrating complications.

METHODS

Patients treated with exclusive enteral nutrition prior to surgery were each matched with two control patients for disease behaviour, type of surgery, age at diagnosis and disease duration. Data on disease phenotype, nutritional status, operative course and post-operative complications were obtained.

RESULTS

Twenty-five per cent [13/51] patients treated with exclusive enteral nutrition avoided surgery. Exclusive enteral nutrition had no effect on pre-operative weight, but it significantly reduced serum CRP [median at baseline 36 (interquartile range, IQR: 13-91] vs. pre-operation 8 (4-31) mg/L, P = 0.02]. The median (IQR) length of surgery was shorter in patients pre-optimised with exclusive enteral nutrition than controls [3.0 (2.5-3.5) vs. 3.5 (3.0-4.0) hours respectively, P < 0.001]. Multivariable logistic regression analysis confirmed that going straight-to-surgery compared exclusive enteral nutrition pre-optimisation was associated with a ninefold increase in the incidence of post-operative abscess and/or anastomotic leak [OR 9.1; 95% CI (1.2-71.2), P = 0.04].

CONCLUSIONS

Exclusive enteral nutrition frequently down-stages the need for surgery in patients presenting with stricturing or penetrating complications of Crohn's disease; it is associated with a reduction in systemic inflammation, operative times and the incidence of post-operative abscess or anastomotic leak. Further trials are needed to elucidate how exclusive enteral nutrition may improve operative outcomes.

207 EFFICIENT GENERATION OF MYOSTATIN PROMOTER MUTATIONS IN BOVINE EMBRYOS USING THE CRISPR/Cas9 SYSTEM

The myostatin gene or growth differentiation factor 8 is a member of the transforming growth factor-β superfamily that acts as a negative regulator of muscle growth. Mutations inactivating this gene occur naturally in Piedmontese and Belgian Blue cattle breeds, resulting in a dramatic increase in muscle mass, albeit with unwanted consequences of increased dystocia and decreased fertility. Modulation of muscle mass increase without the unwanted effects would be of great value for improving livestock growth and economic value of livestock. The objective of our work was to use the CRISPR-Cas9 genetic engineering tool to generate deletions of different elements in the myostatin promoter in order to decrease the level of expression and obtain an attenuated phenotype without the detrimental consequences of an inactivating mutation. To achieve this objective 4 different small guide RNA (sgRNA) targeting the promoter near the mutation were designed with PAM positions from transcription starting site of −1577, −689, −555, and −116. These sgRNA were cloned individually into the Cas9 plasmids (px461, and px462; Addgene®). These plasmids allow for a dual puromycin resistance (px462) and green fluorescent protein (px461) selection. We first tested the functionality of these sgRNA in vitro by co-transfecting bovine fetal fibroblasts with a combination of both plasmids (Set 1 = sgRNA 1–4; Set 2 = sgRNA 2–3). Cells were exposed to puromycin (0.2 µg mL−1) for 72 h, then single and mixed colonies positive for green fluorescent protein expression were separated for propagation. The DNA was extracted for PCR amplification of the targeted region. Multiple deletions and a few insertion events were observed after PCR, bands were cloned into TOPO® vector (Thermo Fisher Scientific, Waltham, MA, USA) and sequenced. Sequencing results confirmed the PCR products as insertions or deletions in the myostatin promoter region. We proceeded to modify the myostatin promoter directly in bovine zygotes. For this, IVF-derived zygotes were randomly assigned to 3 different treatment groups Set 1, Set 2, or Null (no sgRNA) for microinjections. Each zygote was injected with ~100 pL of trophectoderm buffer containing 50 ng µL−1 of total sgRNA, 10 ng µL−1 of Cas9 mRNA, and 30 ng µL−1 of Cas9 protein with 1 mg mL−1 of fluorescent dextran. Day 7 post-IVF blastocysts were lysed and DNA was extracted for PCR amplification of the target region. In Set 1, 16 of 19 embryos (94.12%) were successfully edited, whereas in Set 2 there were 11 of 17 embryos (64.7%) edited. In both sets of sgRNA there was a high degree of mosaicism, with only 1 embryo demonstrating a homozygous deletion. In conclusion, CRISPR/Cas9 acts over the course of the first few cleavage divisions Further research is necessary to refine the CRISPR/Cas9 system for inducing genetic mutations in bovine embryos.

Associations between diet and cardiometabolic risk among Yup'ik Alaska Native people using food frequency questionnaire dietary patterns

BACKGROUND AND AIMS

In previous analyses, we identified three dietary patterns from food frequency questionnaire data among a sample of Yup'ik Alaska Native people living in Southwest Alaska: a "subsistence foods" dietary pattern and two market-based dietary patterns "processed foods" and "fruits and vegetables". In this analysis, we aimed to characterize the association between the dietary patterns and cardiometabolic (CM) risk factors (lipids, blood pressure, glucose, adiposity).

METHODS AND RESULTS

We used multilevel linear regression to estimate the mean of each CM risk factor, comparing participants in the 4th to the 1st quartile of each dietary pattern (n = 637). Models were adjusted for age, sex, past smoking, current smoking, and physical activity. Mean log triglyceride levels were significantly higher among participants in the 4th compared to the 1st quartile of the processed foods dietary pattern (β = 0.11). Mean HbA1c percent was significantly lower (β = -0.08) and mean diastolic blood pressure (DBP) mm Hg was significantly higher (β = 2.87) among participants in the 4th compared to the 1st quartile of the fruits and vegetables dietary pattern. Finally, mean log triglyceride levels and mean DBP mm Hg were significantly lower among participants in the 4th compared to the 1st quartile of the subsistence foods dietary pattern (β = -0.10 and β = -3.99 respectively).

CONCLUSIONS

We found increased CM risk, as reflected by increased triglycerides, associated with eating a greater frequency of processed foods, and reduced CM risk, as reflected by lower triglycerides and DBP, associated with eating a greater frequency of subsistence foods.

OPTN/SRTR 2013 Annual Data Report: kidney

A new kidney allocation system, expected to be implemented in late 2014, will characterize donors on a percent scale (0%-100%) using the kidney donor profile index (KDPI). The 20% of deceased donor kidneys with the greatest expected posttransplant longevity will be allocated first to the 20% of candidates with the best expected posttransplant survival; kidneys that are not accepted will then be offered to remaining 80% of candidates. Waiting time will start at the time of maintenance dialysis initiation (even if before listing) or at the time of listing with an estimated glomerular filtration rate of 20 mL/min/1.73 m(2) or less. Under the current system, the number of candidates on the waiting list continues to increase, as each year more candidates are added than are removed. Median waiting times for adults increased from 3 years in 2003 to more than 4.5 years in 2009. Donation rates have not increased. Short-term outcomes continue to improve; death-censored graft survival at 90 days posttransplant was 97% or higher for deceased donor transplants and over 99% for living donor transplants. In 2013, 883 pediatric candidates were added to the waiting list; 65.8% of pediatric candidates on the list in 2013 underwent deceased donor transplant. Five-year graft survival was highest for living donor recipients aged younger than 11 years (89%) and lowest for deceased donor recipients aged 11 to 17 years (68%).

From network analysis to risk analysis--An approach to risk-based surveillance for bovine tuberculosis in Minnesota, US

Bovine tuberculosis (bTB) was first detected in 2005 in cattle in northwestern Minnesota (MN) through slaughter surveillance. By the end of 2008, 12 cattle herds were infected with bTB, and the main cause for infection was determined to be the movement of infected animals between herds. Bovine tuberculosis was contained in a smaller area in northwestern Minnesota classified as modified accredited (MA), corresponding to a prevalence inferior to 0.1% in cattle. From January 2008 to 2011, all cattle movements within the bTB MA were recorded electronically. The primary objectives of this study were to characterize cattle movements within this region and identify cattle herds with higher risk of bTB introduction based on network parameters and known risk factors from the published literature. During the period that data was collected, 57,460 cattle were moved in 3762 movements corresponding to permits issued to 682 premises, mostly representing private farms, sale yards, slaughter facilities and county or state fairs. Although sale yards represented less than 2% of the premises (nodes), 60% of the movements were to or from a sale yard. The network showed an overall density of 0.4%, a clustering coefficient of 14.6% and a betweenness centralization index of 12.7%, reflecting the low connectivity of this cattle network. The degree distribution showed that 20% of nodes performed 90% of the movements. Farms were ranked based on the total risk score and divided into high, medium, and low risk groups based on the score and its variability. The higher risk group included 14% (n=50) of the farms, corresponding to 80% of the cumulative risk for the farms in the bTB area. This analysis provides a baseline description about the contact structure of cattle movements in an area previously infected with bTB and develops a framework for a targeted surveillance approach for bTB to support future surveillance decisions.