Visuospatial cognition predicts performance on an obstructed vision obstacle walking task in older adults

Walking performance and cognitive function demonstrate strong associations in older adults, with both declining with advancing age. Walking requires the use of cognitive resources, particularly in complex environments like stepping over obstacles. A commonly implemented approach for measuring the cognitive control of walking is a dual-task walking assessment, in which walking is combined with a second task. However, dual-task assessments have shortcomings, including issues with scaling the task difficulty and controlling for task prioritization. Here we present a new assessment designed to be less susceptible to these shortcomings while still challenging cognitive control of walking: the Obstructed Vision Obstacle (OBVIO) task. During the task, participants hold a lightweight tray at waist level obstructing their view of upcoming foam blocks, which are intermittently spaced along a 10 m walkway. This forces the participants to use cognitive resources (e.g., attention and working memory) to remember the exact placement of upcoming obstacles to facilitate successful crossing. The results demonstrate that adding the obstructed vision board significantly slowed walking speed by an average of 0.26 m/s and increased the number of obstacle strikes by 8-fold in healthy older adults (n = 74). Additionally, OBVIO walking performance (a score based on both speed and number of obstacle strikes) significantly correlated with computer-based assessments of visuospatial working memory, attention, and verbal working memory. These results provide initial support that the OBVIO task is a feasible walking test that demands cognitive resources. This study lays the groundwork for using the OBVIO task in future assessment and intervention studies.

Examining chromatin heterogeneity through PacBio long-read sequencing of M.EcoGII methylated genomes: an m6A detection efficiency and calling bias correcting pipeline

Recent studies have combined DNA methyltransferase footprinting of genomic DNA in nuclei with long-read sequencing, resulting in detailed chromatin maps for multi-kilobase stretches of genomic DNA from one cell. Theoretically, nucleosome footprints and nucleosome-depleted regions can be identified using M.EcoGII, which methylates adenines in any sequence context, providing a high-resolution map of accessible regions in each DNA molecule. Here, we report PacBio long-read sequence data for budding yeast nuclei treated with M.EcoGII and a bioinformatic pipeline which corrects for three key challenges undermining this promising method. First, detection of m6A in individual DNA molecules by the PacBio software is inefficient, resulting in false footprints predicted by random gaps of seemingly unmethylated adenines. Second, there is a strong bias against m6A base calling as AT content increases. Third, occasional methylation occurs within nucleosomes, breaking up their footprints. After correcting for these issues, our pipeline calculates a correlation coefficient-based score indicating the extent of chromatin heterogeneity within the cell population for every gene. Although the population average is consistent with that derived using other techniques, we observe a wide range of heterogeneity in nucleosome positions at the single-molecule level, probably reflecting cellular chromatin dynamics.

Evaluating patient factors, operative management and postoperative outcomes in trauma laparotomy patients worldwide: a protocol for a global observational multicentre trauma study

INTRODUCTION

Trauma contributes to the greatest loss of disability-adjusted life-years for adolescents and young adults worldwide. In the context of global abdominal trauma, the trauma laparotomy is the most commonly performed operation. Variation likely exists in how these patients are managed and their subsequent outcomes, yet very little global data on the topic currently exists. The objective of the GOAL-Trauma study is to evaluate both patient and injury factors for those undergoing trauma laparotomy, their clinical management and postoperative outcomes.

METHODS

We describe a planned prospective multicentre observational cohort study of patients undergoing trauma laparotomy. We will include patients of all ages who present to hospital with a blunt or penetrating injury and undergo a trauma laparotomy within 5 days of presentation to the treating centre. The study will collect system, patient, process and outcome data, following patients up until 30 days postoperatively (or until discharge or death, whichever is first). Our sample size calculation suggests we will need to recruit 552 patients from approximately 150 recruiting centres.

DISCUSSION

The GOAL-Trauma study will provide a global snapshot of the current management and outcomes for patients undergoing a trauma laparotomy. It will also provide insight into the variation seen in the time delays for receiving care, the disease and patient factors present, and patient outcomes. For current standards of trauma care to be improved worldwide, a greater understanding of the current state of trauma laparotomy care is paramount if appropriate interventions and targets are to be identified and implemented.

No-Reflow Prediction in Acute Coronary Syndrome During Percutaneous Coronary Intervention: The NORPACS Risk Score

BACKGROUND

Suboptimal coronary reperfusion (no reflow) is common in acute coronary syndrome percutaneous coronary intervention (PCI) and is associated with poor outcomes. We aimed to develop and externally validate a clinical risk score for angiographic no reflow for use following angiography and before PCI.

METHODS

We developed and externally validated a logistic regression model for prediction of no reflow among adult patients undergoing PCI for acute coronary syndrome using data from the Melbourne Interventional Group PCI registry (2005-2020; development cohort) and the British Cardiovascular Interventional Society PCI registry (2006-2020; external validation cohort).

RESULTS

A total of 30 561 patients (mean age, 64.1 years; 24% women) were included in the Melbourne Interventional Group development cohort and 440 256 patients (mean age, 64.9 years; 27% women) in the British Cardiovascular Interventional Society external validation cohort. The primary outcome (no reflow) occurred in 4.1% (1249 patients) and 9.4% (41 222 patients) of the development and validation cohorts, respectively. From 33 candidate predictor variables, 6 final variables were selected by an adaptive least absolute shrinkage and selection operator regression model for inclusion (cardiogenic shock, ST-segment-elevation myocardial infarction with symptom onset >195 minutes pre-PCI, estimated stent length ≥20 mm, vessel diameter <2.5 mm, pre-PCI Thrombolysis in Myocardial Infarction flow <3, and lesion location). Model discrimination was very good (development C statistic, 0.808; validation C statistic, 0.741) with excellent calibration. Patients with a score of ≥8 points had a 22% and 27% risk of no reflow in the development and validation cohorts, respectively.

CONCLUSIONS

The no-reflow prediction in acute coronary syndrome risk score is a simple count-based scoring system based on 6 parameters available before PCI to predict the risk of no reflow. This score could be useful in guiding preventative treatment and future trials.

Brain Expression of CPB2 and Effects of Cpb2 Deficiency in Mouse Models of Behavior

BACKGROUND

 Procarboxypeptidase B2 (proCPB2 or TAFI) is a zymogen that after activation cleaves C-terminal basic residues from peptides or proteins with many identified targets. A splice variant of CPB2 has been found in the brain lacking essential residues for its carboxypeptidase function. The aim was to determine CPB2 expression in the brain and effects of CPB2 deficiency (Cpb2 -/-) on behavior.

MATERIALS AND METHODS

 Behavioral effects were tested by comparing Cpb2 -/- mice in short-term (open field and elevated zero maze tests) and long-term (Phenotyper) observations with wild-type (WT) controls.

RESULTS

 Long-term observation compared day 1 (acclimatizing to novel environment) to day 4 (fully acclimatized) with the inactive (day) and active (night) periods analyzed separately. Brain expression of CPB2 mRNA and protein was interrogated in publicly available databases. Long-term observation demonstrated differences between WT and Cpb2 -/- mice in several parameters. For example, Cpb2 -/- mice moved more frequently on both days 1 and 4, especially in the normally inactive periods. Cpb2 -/- mice spent more time on the shelter and less time in it. Differences were more pronounced on day 4 after the mice had fully acclimatized. In short-term observations, no differences were observed between Cpb2 -/- mice and WT mice. Brain expression of CBP2 was not detectable in the human protein atlas. Databases of single-cell RNAseq did not show expression of CPB2 mRNA in either human or mouse brain.

CONCLUSION

 Continuous observation of home-cage behavior suggests that Cpb2 -/- mice are more active than WT mice, show different day-night activity levels, and might have a different way of processing information.

Sex Differences in Pharmacotherapy and Long-Term Outcomes in Patients With Ischaemic Heart Disease and Comorbid Left Ventricular Dysfunction

BACKGROUND

Left ventricular (LV) dysfunction and ischaemic heart disease (IHD) are common among women. However, women tend to present later and are less likely to receive guideline-directed medical therapy (GDMT) compared with men.

METHODS

We analysed prospectively collected data (2005-2018) from a multicentre registry on GDMT 30 days after percutaneous coronary intervention in 13,015 patients with LV ejection fraction <50%. Guideline-directed medical therapy was defined as beta blocker, angiotensin-converting enzyme inhibitor/angiotensin receptor blocker±mineralocorticoid receptor antagonist. Long-term mortality was determined by linkage with the Australian National Death Index.

RESULTS

Women represented 20% (2,634) of the total cohort. Mean age was 65±12 years. Women were on average >5 years, with higher body mass index and higher rates of hypertension, diabetes, renal dysfunction, prior stroke, and rheumatoid arthritis. Guideline-directed medical therapy was similar between sexes (73% vs 72%; p=0.58), although women were less likely to be on an angiotensin-converting enzyme inhibitor/angiotensin receptor blocker (80% vs 82%; p=0.02). Women were less likely to be on statin therapy (p<0.001) or a second antiplatelet agent (p=0.007). Women had higher unadjusted long-term mortality (25% vs 19%; p<0.001); however, there were no differences in long-term mortality between sexes on adjusted analysis (hazard ratio 0.99; 95% confidence interval 0.87-1.14; p=0.94).

CONCLUSIONS

Rates of GDMT for LV dysfunction were high and similar between sexes; however, women were less likely to be on appropriate IHD secondary prevention. The increased unadjusted long-term mortality in women was attenuated in adjusted analysis, which highlights the need for optimisation of baseline risk to improve long-term outcomes of women with IHD and comorbid LV dysfunction.

Examining chromatin heterogeneity through PacBio long-read sequencing of M.EcoGII methylated genomes: an m6A detection efficiency and calling bias correcting pipeline

Recent studies have combined DNA methyltransferase footprinting of genomic DNA in nuclei with long-read sequencing, resulting in detailed chromatin maps for multi-kilobase stretches of genomic DNA from one cell. Theoretically, nucleosome footprints and nucleosome-depleted regions can be identified using M.EcoGII, which methylates adenines in any sequence context, providing a high-resolution map of accessible regions in each DNA molecule. Here we report PacBio long-read sequence data for budding yeast nuclei treated with M.EcoGII and a bioinformatic pipeline which corrects for three key challenges undermining this promising method. First, detection of m6A in individual DNA molecules by the PacBio software is inefficient, resulting in false footprints predicted by random gaps of seemingly unmethylated adenines. Second, there is a strong bias against m6A base calling as AT content increases. Third, occasional methylation occurs within nucleosomes, breaking up their footprints. After correcting for these issues, our pipeline calculates a correlation coefficient-based score indicating the extent of chromatin heterogeneity within the cell population for every gene. Although the population average is consistent with that derived using other techniques, we observe a wide range of heterogeneity in nucleosome positions at the single-molecule level, probably reflecting cellular chromatin dynamics.

Sympathetic nervous system responses during complex walking tasks and community ambulation post-stroke

Stroke survivors frequently report increased perceived challenge of walking (PCW) in complex environments, restricting their daily ambulation. PCW is conventionally measured through subjective questionnaires or, more recently, through objective quantification of sympathetic nervous system activity during walking tasks. However, how these measurements of PCW reflect daily walking activity post-stroke is unknown. We aimed to compare the subjective and objective assessments of PCW in predicting home and community ambulation. In 29 participants post-stroke, we measured PCW subjectively with the Activities-specific Balance Confidence (ABC) Scale and objectively through electrodermal activity, quantified by change in skin conductance levels (SCL) and skin conductance responses (SCR) between outdoor-complex and indoor-steady-state walking. High-PCW participants were categorized into high-change SCL (ΔSCL ≥ 1.7 μs), high-change SCR (ΔSCR ≥ 0.2 μs) and low ABC (ABC < 72%) groups, while low-PCW participants were categorized into low-change SCL (ΔSCL < 1.7 μs), low-change SCR (ΔSCR < 0.2 μs) and high-ABC (ABC ≥ 72%) groups. Number and location of daily steps were quantified with accelerometry and Global Positioning System devices. Compared to low-change SCL group, the high-change SCL group took fewer steps in home and community (p = 0.04). Neither ABC nor SCR groups differed in home or community steps/day. Objective measurement of PCW via electrodermal sensing more accurately represents home and community ambulation compared to the subjective questionnaire.

Impact of Preprocedural Diastolic Blood Pressure on Outcomes in Patients Undergoing Percutaneous Coronary Intervention

BACKGROUND

Recent US guidelines recommend lower blood pressure (BP) targets in hypertension, but aggressive lowering of diastolic BP (DBP) can occur at the expense of myocardial perfusion, particularly in the presence of coronary artery disease. We sought to establish the long-term impact of low DBP on mortality among patients undergoing percutaneous coronary intervention with well-controlled systolic BP.

METHODS

We analyzed data from 12 965 patients undergoing percutaneous coronary intervention between 2009 and 2018 from the Melbourne Interventional Group registry who had a preprocedural systolic BP of ≤140 mm Hg. Patients with ST-elevation myocardial infarction, cardiogenic shock, and out-of-hospital arrest were excluded. Patients were stratified into 5 groups according to preprocedural DBP: <50, 50 to 59, 60 to 69, 70 to 79, and ≥80 mm Hg. The primary outcome was long-term, all-cause mortality. Mortality data were derived from the Australian National Death Index.

RESULTS

Patients with DBP<50 mm Hg were older with higher rates of diabetes, renal impairment, prior myocardial infarction, left ventricular dysfunction, peripheral and cerebrovascular disease (all P<0.001). Patients with DBP<50 mm Hg had higher 30-day (2.5% versus 0.7% for the other 4 quintiles; P<0.0001) and long-term mortality (median, 3.6 years; follow-up, 29% versus 11%; P<0.0001). Cox-regression analysis revealed that DBP<50 mm Hg was an independent predictor of long-term mortality (hazard ratio [HR], 1.55 [95% CI, 1.20-2.00]; P=0.001).

CONCLUSIONS

In patients with well-controlled systolic BP undergoing percutaneous coronary intervention, low DBP (<50 mm Hg) is an independent predictor of long-term mortality.

Electrical Brain Activity during Human Walking with Parametric Variations in Terrain Unevenness and Walking Speed

Mobile brain imaging with high-density electroencephalography (EEG) can provide insight into the cortical processes involved in complex human walking tasks. While uneven terrain is common in the natural environment and poses challenges to human balance control, there is limited understanding of the supraspinal processes involved with traversing uneven terrain. The primary objective of this study was to quantify electrocortical activity related to parametric variations in terrain unevenness for neurotypical young adults. We used high-density EEG to measure brain activity when thirty-two young adults walked on a novel custom-made uneven terrain treadmill surface with four levels of difficulty at a walking speed tailored to each participant. We identified multiple brain regions associated with uneven terrain walking. Alpha (8 - 13 Hz) and beta (13 - 30 Hz) spectral power decreased in the sensorimotor and posterior parietal areas with increasing terrain unevenness while theta (4 - 8 Hz) power increased in the mid/posterior cingulate area with terrain unevenness. We also found that within stride spectral power fluctuations increased with terrain unevenness. Our secondary goal was to investigate the effect of parametric changes in walking speed (0.25 m/s, 0.5m/s, 0.75 m/s, 1.0 m/s) to differentiate the effects of walking speed from uneven terrain. Our results revealed that electrocortical activities only changed substantially with speed within the sensorimotor area but not in other brain areas. Together, these results indicate there are distinct cortical processes contributing to the control of walking over uneven terrain versus modulation of walking speed on smooth, flat terrain. Our findings increase our understanding of cortical involvement in an ecologically valid walking task and could serve as a benchmark for identifying deficits in cortical dynamics that occur in people with mobility deficits.

The QuantuMDx Q-POC SARS-CoV-2 RT-PCR assay for rapid detection of COVID-19 at point-of-care: preliminary evaluation of a novel technology

Accurate and rapid point-of-care (PoC) diagnostics are critical to the control of the COVID-19 pandemic. The current standard for accurate diagnosis of SARS-CoV-2 is laboratory-based reverse transcription polymerase chain reaction (RT-PCR) assays. Here, a preliminary prospective performance evaluation of the QuantuMDx Q-POC SARS-CoV-2 RT-PCR assay is reported. Between November 2020 and March 2021, 49 longitudinal combined nose/throat (NT) swabs from 29 individuals hospitalised with RT-PCR confirmed COVID-19 were obtained at St George's Hospital, London. In addition, 101 mid-nasal (MN) swabs were obtained from healthy volunteers in June 2021. These samples were used to evaluate the Q-POC SARS-CoV-2 RT-PCR assay. The primary analysis was to compare the sensitivity and specificity of the Q-POC test against a reference laboratory-based RT-PCR assay. The overall sensitivity of the Q-POC test compared with the reference test was 96.88% (83.78- 99.92% CI) for a cycle threshold (Ct) cut-off value for the reference test of 35 and 80.00% (64.35-90.95% CI) without altering the reference test's Ct cut-off value of 40. The Q-POC test is a sensitive, specific and rapid PoC test for SARS-CoV-2 at a reference Ct cut-off value of 35. The Q-POC test provides an accurate option for RT-PCR at PoC without the need for sample pre-processing and laboratory handling, enabling rapid diagnosis and clinical triage in acute care and other settings.

Comparison of EEG Source Localization Using Simplified and Anatomically Accurate Head Models in Younger and Older Adults

Accuracy of electroencephalography (EEG) source localization relies on the volume conduction head model. A previous analysis of young adults has shown that simplified head models have larger source localization errors when compared with head models based on magnetic resonance images (MRIs). As obtaining individual MRIs may not always be feasible, researchers often use generic head models based on template MRIs. It is unclear how much error would be introduced using template MRI head models in older adults that likely have differences in brain structure compared to young adults. The primary goal of this study was to determine the error caused by using simplified head models without individual-specific MRIs in both younger and older adults. We collected high-density EEG during uneven terrain walking and motor imagery for 15 younger (22±3 years) and 21 older adults (74±5 years) and obtained [Formula: see text]-weighted MRI for each individual. We performed equivalent dipole fitting after independent component analysis to obtain brain source locations using four forward modeling pipelines with increasing complexity. These pipelines included: 1) a generic head model with template electrode positions or 2) digitized electrode positions, 3) individual-specific head models with digitized electrode positions using simplified tissue segmentation, or 4) anatomically accurate segmentation. We found that when compared to the anatomically accurate individual-specific head models, performing dipole fitting with generic head models led to similar source localization discrepancies (up to 2 cm) for younger and older adults. Co-registering digitized electrode locations to the generic head models reduced source localization discrepancies by  ∼  6 mm. Additionally, we found that source depths generally increased with skull conductivity for the representative young adult but not as much for the older adult. Our results can help inform a more accurate interpretation of brain areas in EEG studies when individual MRIs are unavailable.

Pain severity, distribution, and duration are associated with spatiotemporal gait performance in community-dwelling older adults with chronic musculoskeletal pain

BACKGROUND

Our current understanding of the impact of chronic pain on spatiotemporal gait performance has mainly been achieved through comparison studies between individuals with and without chronic pain. Further investigation into the relationship between specific outcome measures of chronic pain and gait may improve our understanding of the impact of pain on gait and may benefit future interventions that aim to improve mobility in this population.

RESEARCH QUESTION

Which pain outcome measures are associated with spatiotemporal gait performance in older adults with chronic musculoskeletal pain?

METHODS

This study was secondary analysis of older adult participants enrolled in the Neuromodulatory Examination of Pain and Mobility Across the Lifespan (NEPAL) study (n = 43). Pain outcome measures were obtained using self-reported questionnaires, and spatiotemporal gait analysis was conducted using an instrumented gait mat. Separate multiple linear regressions were run to determine which pain outcome measurements were associated with gait performance.

RESULTS

Higher pain severities were associated with shorter stride lengths (β = -0.336, p = 0.041), shorter swing times (β = -0.345, p = 0.037), and longer double support times (β = 0.342, p = 0.034). A greater number of pain sites was associated with a wider step width (β = 0.391, p = 0.024). Longer pain durations were associated with shorter double support times (β = -0.373, p = 0.022).

SIGNIFICANCE

The results of our study illustrate that specific pain outcomes measures are associated with specific gait impairments in community-dwelling older adults with chronic musculoskeletal pain. As such, pain severity, number of pain sites, and pain duration should be considered when developing mobility interventions in this population to reduce disability.

Trends in Intra-Aortic Balloon Pump Use in Cardiogenic Shock After the SHOCK-II Trial

Myocardial infarction complicated by cardiogenic shock (MI-CS) has a poor prognosis, even with early revascularization. Previously, intra-aortic balloon pump (IABP) use was thought to improve outcomes, but the IABP-SHOCK-II (Intra-aortic Balloon Pump in Cardiogenic Shock-II study) trial found no survival benefit. We aimed to determine the trends in IABP use in patients who underwent percutaneous intervention over time. Data were taken from patients in the Melbourne Interventional Group registry (2005 to 2018) with MI-CS who underwent percutaneous intervention. The primary outcome was the trend in IABP use over time. The secondary outcomes included 30-day mortality and major adverse cardiovascular and cerebrovascular events (MACCEs). Of the 1,110 patients with MI-CS, IABP was used in 478 patients (43%). IABP was used more in patients with left main/left anterior descending culprit lesions (62% vs 46%), lower ejection fraction (<35%; 18% vs 11%), and preprocedural inotrope use (81% vs 73%, all p <0.05). IABP use was associated with higher bleeding (18% vs 13%) and 30-day MACCE (58% vs 51%, both p <0.05). The rate of MI-CS per year increased over time; however, after 2012, there was a decrease in IABP use (p <0.001). IABP use was a predictor of 30-day MACCE (odds ratio 1.6, 95% confidence interval 1.18 to 2.29, p = 0.003). However, IABP was not associated with in-hospital, 30-day, or long-term mortality (45% vs 47%, p = 0.44; 46% vs 50%, p = 0.25; 60% vs 62%, p = 0.39). In conclusion, IABP was not associated with reduced short- or long-term mortality and was associated with increased short-term adverse events. IABP use is decreasing but is predominately used in sicker patients with greater myocardium at risk.

Uneven terrain versus dual-task walking: differential challenges imposed on walking behavior in older adults are predicted by cognitive and sensorimotor function

Aging is associated with declines in walking function. To understand these mobility declines, many studies have obtained measurements while participants walk on flat surfaces in laboratory settings during concurrent cognitive task performance (dual-tasking). This may not adequately capture the real-world challenges of walking at home and around the community. Here, we hypothesized that uneven terrains in the walking path impose differential changes to walking speed compared to dual-task walking. We also hypothesized that changes in walking speed resulting from uneven terrains will be better predicted by sensorimotor function than cognitive function. Sixty-three community-dwelling older adults (65-93 yrs old) performed overground walking under varying walking conditions. Older adults were classified into two mobility function groups based on scores of the Short Physical Performance Battery. They performed uneven terrain walking across four surface conditions (Flat, Low, Medium, and High unevenness) and performed single and verbal dual-task walking on flat ground. Participants also underwent a battery of cognitive (cognitive flexibility, working memory, inhibition) and sensorimotor testing (grip strength, 2-pt discrimination, pressure pain threshold). Our results showed that walking speed decreased during both dual-task walking and across uneven terrain walking conditions compared to walking on flat terrain. Participants with lower mobility function had even greater decreases in uneven terrain walking speeds. The change in uneven terrain speed was associated with attention and inhibitory function. Changes in both dual-task and uneven terrain walking speeds were associated with 2-point tactile discrimination. This study further documents associations between mobility, executive functions, and somatosensation, highlights the differential costs to walking imposed by uneven terrains, and identifies that older adults with lower mobility function are more likely to experience these changes to walking function.

The next "sweet" spot for pancreatic ductal adenocarcinoma: Glycoprotein for early detection

Pancreatic ductal adenocarcinoma (PDAC) is the most common neoplastic disease of the pancreas, accounting for more than 90% of all pancreatic malignancies. As a highly lethal malignancy, PDAC is the fourth leading cause of cancer-related deaths worldwide with a 5-year overall survival of less than 8%. The efficacy and outcome of PDAC treatment largely depend on the stage of disease at the time of diagnosis. Surgical resection followed by adjuvant chemotherapy remains the only possibly curative therapy, yet 80%-90% of PDAC patients present with nonresectable PDAC stages at the time of clinical presentation. Despite our advancing knowledge of PDAC, the prognosis remains strikingly poor, which is primarily due to the difficulty of diagnosing PDAC at the early stages. Recent advances in glycoproteomics and glycomics based on mass spectrometry have shown that aberrations in protein glycosylation plays a critical role in carcinogenesis, tumor progression, metastasis, chemoresistance, and immuno-response of PDAC and other types of cancers. A growing interest has thus been placed upon protein glycosylation as a potential early detection biomarker for PDAC. We herein take stock of the advancements in the early detection of PDAC that were carried out with mass spectrometry, with special focus on protein glycosylation.

Age-related changes in gait biomechanics and their impact on the metabolic cost of walking: Report from a National Institute on Aging workshop

Changes in old age that contribute to the complex issue of an increased metabolic cost of walking (mass-specific energy cost per unit distance traveled) in older adults appear to center at least in part on changes in gait biomechanics. However, age-related changes in energy metabolism, neuromuscular function and connective tissue properties also likely contribute to this problem, of which the consequences are poor mobility and increased risk of inactivity-related disease and disability. The U.S. National Institute on Aging convened a workshop in September 2021 with an interdisciplinary group of scientists to address the gaps in research related to the mechanisms and consequences of changes in mobility in old age. The goal of the workshop was to identify promising ways to move the field forward toward improving gait performance, decreasing energy cost, and enhancing mobility for older adults. This report summarizes the workshop and brings multidisciplinary insight into the known and potential causes and consequences of age-related changes in gait biomechanics. We highlight how gait mechanics and energy cost change with aging, the potential neuromuscular mechanisms and role of connective tissue in these changes, and cutting-edge interventions and technologies that may be used to measure and improve gait and mobility in older adults. Key gaps in the literature that warrant targeted research in the future are identified and discussed.

Characteristics of Radial Artery Coronary Bypass Graft Failure and Outcomes Following Subsequent Percutaneous Coronary Intervention

BACKGROUND

When patients with prior coronary artery bypass grafting (CABG) undergo percutaneous coronary intervention (PCI), targeting the native vessel is preferred. Studies informing such recommendations are based predominantly on saphenous vein graft (SVG) PCI. There are few data regarding arterial graft intervention, particularly to a radial artery (RA) graft.

OBJECTIVES

The aim of this study was to report the characteristics of arterial graft stenoses and evaluate the feasibility of RA PCI.

METHODS

This study included 2,780 consecutive patients with prior CABG undergoing PCI between 2005 and 2018 who were prospectively enrolled in the MIG (Melbourne Interventional Group) registry. Data were stratified by PCI target vessel. RA graft PCI was compared with both native vessel (native PCI) and SVG PCI. Internal mammary graft PCI data were reported. The primary outcome was 3-year mortality.

RESULTS

Overall, 1,928 patients (69.4%) underwent native PCI, 716 (25.6%) SVG PCI, 86 (3.1%) RA PCI, and 50 (1.8%) internal mammary graft PCI. Compared with SVG PCI, the RA PCI cohort presented earlier after CABG, less frequently had acute coronary syndrome, and more commonly had ostial or distal anastomosis intervention (P < 0.005 for all). Compared with patients who underwent native PCI, those who underwent RA PCI were more likely to have diabetes and peripheral vascular disease (P < 0.001 for both) and to present with non-ST-segment elevation myocardial infarction (P = 0.010). The RA PCI group had no perforations or in-hospital myocardial infarctions, though no significant difference was found in periprocedural outcomes compared with either native or SVG PCI. No differences were found between RA PCI and either native or SVG PCI in 30-day outcomes or 3-year mortality.

CONCLUSIONS

Presenting and lesion characteristics differed between patients undergoing arterial compared with SVG PCI, implying a varied pathogenesis of graft stenosis. RA PCI appears feasible, safe, and where anatomically suitable, may be a viable alternative to native PCI.

Histopathologic and proteogenomic heterogeneity reveals features of clear cell renal cell carcinoma aggressiveness

Clear cell renal cell carcinomas (ccRCCs) represent ∼75% of RCC cases and account for most RCC-associated deaths. Inter- and intratumoral heterogeneity (ITH) results in varying prognosis and treatment outcomes. To obtain the most comprehensive profile of ccRCC, we perform integrative histopathologic, proteogenomic, and metabolomic analyses on 305 ccRCC tumor segments and 166 paired adjacent normal tissues from 213 cases. Combining histologic and molecular profiles reveals ITH in 90% of ccRCCs, with 50% demonstrating immune signature heterogeneity. High tumor grade, along with BAP1 mutation, genome instability, increased hypermethylation, and a specific protein glycosylation signature define a high-risk disease subset, where UCHL1 expression displays prognostic value. Single-nuclei RNA sequencing of the adverse sarcomatoid and rhabdoid phenotypes uncover gene signatures and potential insights into tumor evolution. In vitro cell line studies confirm the potential of inhibiting identified phosphoproteome targets. This study molecularly stratifies aggressive histopathologic subtypes that may inform more effective treatment strategies.

Spatiotemporal strategies adopted to walk at fast speed in high- and low-functioning individuals post-stroke: a cross-sectional study

BACKGROUND

Walking at fast speed is a gait training strategy post-stroke. It is unknown how faster-than-preferred pace impacts spatiotemporal gait characteristics in survivors with different functional abilities.

OBJECTIVE

To test the hypothesis that compared to high-functioning individuals, low-functioning individuals will be limited in modifying spatiotemporal gait parameters for walking at faster-than-preferred speed, and these limitations are associated with fear of falling.

METHODS

Forty-two adults, 17.6 ± 14.6 months post-stroke, traversed an instrumented walkway at preferred and fast speeds. Participants were categorized to a low-functioning group (LFG) (n = 20; <0.45 m/s) and high-functioning group (HFG) (n = 22; ≥0.45 m/s). Cadence, step length, stance time and spatiotemporal asymmetry measures were calculated. The Modified Falls-efficacy Scale examined fear of falling. Multivariate and correlational analysis tested hypotheses.

RESULTS

Increased speed from preferred to fast pace was significantly greater for HFG (0.27 ± 0.03 m/s) than LFG (0.10 ± 0.02 m/s) (p ≤ 0.001). Cadence gain from preferred to fast pace did not differ between groups. However, HFG exhibited greater change in paretic (∆6.1 ± 1.37 cm; p < .001) and non-paretic step lengths (∆4.5 ± 1.37 cm; p = .003) than LFG. Spatiotemporal asymmetry did not change for either group. Fear of falling had moderately positive correlation with ∆paretic step length (r = 0.43; p = .004) and ∆non-paretic step length (r = 0.32; p = .035).

CONCLUSIONS

While both low- and high-functioning individuals used a step-lengthening strategy to walk at faster-than-preferred speeds, the gain in step lengths was limited in low-functioning individuals and was partially explained by falls-efficacy.

Uneven terrain treadmill walking in younger and older adults

We developed a method for altering terrain unevenness on a treadmill to study gait kinematics. Terrain consisted of rigid polyurethane disks (12.7 cm diameter, 1.3-3.8 cm tall) which attached to the treadmill belt using hook-and-loop fasteners. Here, we tested four terrain unevenness conditions: Flat, Low, Medium, and High. The main objective was to test the hypothesis that increasing the unevenness of the terrain would result in greater gait kinematic variability. Seventeen younger adults (age 20-40 years), 25 higher-functioning older adults (age 65+ years), and 29 lower-functioning older adults (age 65+ years, Short Physical Performance Battery score < 10) participated. We customized the treadmill speed to each participant's walking ability, keeping the speed constant across all four terrain conditions. Participants completed two 3-minute walking trials per condition. Using an inertial measurement unit placed over the sacrum and pressure sensors in the shoes, we calculated the stride-to-stride variability in step duration and sacral excursion (coefficient of variation; standard deviation expressed as percentage of the mean). Participants also self-reported their perceived stability for each condition. Terrain was a significant predictor of step duration variability, which roughly doubled from Flat to High terrain for all participant groups: younger adults (Flat 4.0%, High 8.2%), higher-functioning older adults (Flat 5.0%, High 8.9%), lower-functioning older adults (Flat 7.0%, High 14.1%). Similarly, all groups exhibited significant increases in sacral excursion variability for the Medium and High uneven terrain conditions, compared to Flat. Participants were also significantly more likely to report feeling less stable walking over all three uneven terrain conditions compared to Flat. These findings support the hypothesis that altering terrain unevenness on a treadmill will increase gait kinematic variability and reduce perceived stability in younger and older adults.

Trends and Real-World Safety of Patients Undergoing Percutaneous Coronary Intervention for Symptomatic Stable Ischaemic Heart Disease in Australia

BACKGROUND

Percutaneous coronary intervention (PCI) in stable ischaemic heart disease (SIHD) has not been shown to improve prognosis but can alleviate symptoms and improve quality of life. Appropriately selected patients with symptoms refractory to medical therapy therefore stand to benefit, provided safety is proven.

METHODS

Consecutive patients undergoing PCI for SIHD between 2005-2018 in a prospective registry were included. Yearly comparisons evaluated trends, and a sub-analysis was performed comparing proximal left anterior descending artery (prox-LAD) to other-than-proximal LAD (non-pLAD) PCI. Outcomes included peri-procedural characteristics, in-hospital and 30-day event rates including MACE, and 5-year National Death Index (NDI) linked mortality.

RESULTS

There were 9,421 procedures included. Over time, patients were increasingly co-morbid and had higher rates of AHA/ACC class B2/C lesions, ostial stenoses, bifurcation lesions, and chronic total occlusions (all p-for-trend ≤0.001). Over 14 years, major bleeding reduced (1.05% in 2005/06 vs 0.29% in 2017/18, p-for-trend <0.001), while other in-hospital and 30-day event rates were stably low. There were only seven (0.07%) in hospital deaths and 5-year mortality was 10.3%. No differences were found in outcomes between patients who underwent prox-LAD compared to non-pLAD PCI. Major independent predictors of NDI linked all-cause mortality included an eGFR <30 mL/min/1.73 m² (HR 4.06, 95% CI 3.26-5.06), chronic obstructive pulmonary disease (COPD) (HR 2.25, 95% CI 1.89-2.67) and LVEF <30% (HR 2.13, 95% CI 1.57-2.89).

CONCLUSIONS

Although patient and procedural complexity increased over time, a high degree of procedural success and safety was maintained, including in those undergoing prox-LAD PCI. These real-world data can enhance shared decision making discussions regarding whether PCI should be pursued in patients with symptomatic SIHD refractory to medical therapy.

SARS-CoV-2 Vaccine Immunogenicity in Patients with Gastrointestinal Cancer Receiving Systemic Anti-Cancer Therapy

INTRODUCTION

Patients with gastrointestinal (GI) cancers have an increased risk of serious complications and death from SARS-CoV-2 infection. The immunogenicity of vaccines in patients with GI cancers receiving anti-cancer therapies is unclear. We conducted a prospective study to evaluate the prevalence of neutralizing antibodies in a cohort of GI cancer patients receiving chemotherapy following SARS-CoV-2 vaccination.

MATERIALS AND METHODS

Between September 2020 and April 2021, patients with cancer undergoing chemotherapy were enrolled. At baseline (day 0), days 28, 56, and 84, we assessed serum antibodies to SARS-CoV-2 spike (anti-S) and anti-nucleocapsid (anti-NP) and concomitantly assessed virus neutralization using a pseudovirus neutralization assay. Patients received either the Pfizer/BioNTech BNT162b2, or the Oxford/AstraZeneca ChAdOx1 vaccine.

RESULTS

All 152 patients enrolled had a prior diagnosis of cancer; colorectal (n = 80, 52.6%), oesophagogastric (n = 38, 25.0%), and hepato pancreatic biliary (n = 22, 12.5%). Nearly all were receiving systemic anti-cancer therapy (99.3%). Of the 51 patients who did not receive a vaccination prior to, or during the study, 5 patients had detectable anti-NP antibodies. Ninety-nine patients received at least one dose of vaccine prior to, or during the study. Within 19 days following the first dose of vaccine, 30.0% had anti-S detected in serum which increased to 70.2% at days 20-39. In the 19 days following a second dose, anti-S positivity was 84.2% (32/38). However, pseudovirus neutralization titers (pVNT80) decreased from days 20 to 39.

CONCLUSION

Despite the immunosuppressive effects of chemotherapy, 2 doses of SARS-CoV-2 vaccines are able to elicit a protective immune response in patients' ongoing treatment for gastrointestinal cancers. Decreases in pseudoviral neutralization were observed after 20-39 days, re-affirming the current recommendation for vaccine booster doses.

CLINICAL TRIAL REGISTRATION NUMBER

NCT04427280.

Somatosensory impairment of the feet is associated with higher activation of prefrontal cortex during walking in older adults

BACKGROUND

Over-activation of prefrontal cortex during walking has been reported in older adults versus young adults. Heighted activity in prefrontal cortex suggests a shift toward an executive control strategy to control walking. A potential contributing factor is degraded functioning of pattern-generating locomotor circuits in the central nervous system that are important to walking coordination. Somatosensory information is a crucial input to these circuits, so age-related impairment of somatosensation would be expected to compromise the neural control of walking. The present study tested the hypothesis that poorer somatosensation in the feet of older adults will be associated with greater recruitment of the prefrontal cortex during walking. This study also examines the extent to which somatosensory function and prefrontal activity are associated with performance on walking and balance assessments.

METHODS

Forty seven older adults (age 74.6 ± 6.8 years; 32 female) participated in walking assessments (typical walking and obstacle negotiation) and Berg Balance Test. During walking, prefrontal activity was measured with functional near infrared spectroscopy (fNIRS). Participants also underwent somatosensory testing with Semmes-Weinstein monofilaments.

RESULTS

The primary findings is that worse somatosensory monofilament level was associated with greater prefrontal cortical activity during typical walking (r = 0.38, p = 0.008) and obstacle negotiation (r = 0.40, p = 0.006). For the obstacle negotiation task, greater prefrontal activity was associated with faster walking speed (p = 0.004). Poorer somatosensation was associated with slower typical walking speed (p = 0.07) and obstacles walking speed (p < 0.001), as well as poorer balance scores (p = 0.03).

CONCLUSIONS

The study findings are consistent with a compensation strategy of recruiting prefrontal/executive control resources to overcome loss of somatosensory input to the central nervous system. Future research should further establish the mechanisms by which somatosensory impairments are linked to the neural control and performance of walking tasks, as well as develop intervention approaches.

Gait subgroups among older adults with chronic pain differ in cerebellum and basal ganglia gray matter volumes

BACKGROUND

Current literature regarding morphological gray matter atrophy in chronic pain is mixed, inhibiting our ability to understand neurological mechanisms of chronic pain. The inconsistent findings may be due to the presence of subgroups within the older adult chronic pain population that differ in gait performance, as gait and gray matter have been previously associated. These gait subgroups, however, have been inadequately characterized in prior work and have not been compared across gray matter measures. Therefore, the purpose of this study was to identify and characterize gait subgroups within the older adult chronic pain population, and to evaluate differences in gray matter measures between subgroups.

METHODS

The present study was a secondary analysis of the Neuromodulatory Examination of Pain and Mobility Across the Lifespan (NEPAL) study. A subset of older participants (n = 40) completed assessments to evaluate psychological status, cognitive abilities, pain characteristics, and spatiotemporal gait performance using an instrumented gait mat. Gray matter measures were obtained from a T1-weighted anatomical scan using Freesurfer's recon-all function.

RESULTS

After data reduction, a hierarchical cluster analysis identified three gait clusters: A Normal Gait cluster (n = 12), a Shuffle Gait cluster (n = 15), and an Unsteady Gait cluster (n = 13). Clusters differed in gait velocity, stride length, step width, double support percentages, and stride length variability. The Shuffle Gait cluster exhibited reduced gray matter volumes in the cerebellum, caudate, putamen, and pallidum, as well as a worse pain severity when compared to the Normal Gait cluster (p < 0.05). The Shuffle Gait cluster also had less gray matter in the cerebellum and caudate when compared to the Unsteady Gait cluster (p < 0.05).

CONCLUSIONS

Our results confirm the existence of gait subgroups among the older adult chronic pain population and gray matter differences observed between groups support the need for the consideration of subgroups within this population for future pain, mobility, and aging studies.

Abstract 1000: E-cadherin and EGFR interactions result in hyper-proliferation via ERK signaling in breast cancer

The loss of the intercellular adhesion molecule E-cadherin is a hallmark of the epithelial-mesenchymal transition (EMT), during which tumor cells transition into an invasive phenotype. Thus, E-cadherin has long been considered a tumor suppressor gene. However, recent studies have provided evidence that E-cadherin may promote metastasis rather than suppress it, suggesting oncogenic behavior. Here we provide data that E-cadherin plays an oncogenic role in breast cancer by promoting a hyper-proliferative phenotype in breast cancer cells via interaction with EGFR. This interaction results in the activation of the MEK/ERK signaling pathway, leading directly to changes in proliferation via transcription factors such as c-Fos. Pharmacological inhibition of MEK in E-cadherin positive breast cancer cells significantly decreases both tumor growth and macro-metastasis in vivo. This work provides evidence for a novel role of E-cadherin in breast tumor progression and identifies a potential new target to treat hyper-proliferative E-cadherin-positive breast tumors.

Citation Format: Gabriella C. Russo, Ashleigh Crawford, David J. Clark, Julie Cui, Ryan Carney, Michelle N. Karl, Boyang Su, Batrholomew Starich, Tung-Shing Lee, Qiming Zhang, Pei-hsun Wu, Meng-Horng Lee, Hon S. Leong, Vito Rebecca, Hui Zhang, Denis Wirtz. E-cadherin and EGFR interactions result in hyper-proliferation via ERK signaling in breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1000.

Kinematic analysis of speed transitions within walking in younger and older adults

The ability to adapt to environmental and task demands while walking is critical to independent mobility outside the home and this ability wanes with age. Such adaptability requires individuals to acutely change their walking speed. Regardless of age, changes between walking speeds are common in daily life, and are a frequent type of walking adaptability. Here, we report on older and younger adults when transitioning from preferred walking speed overground to either slower or faster walking. Specifically, we evaluated biomechanical parameters prior to, during, and post transition. Individuals approached the walking speed transition similarly, independent of whether the transition was to slower or faster walking. Regardless of age or walking speed, the step during which a walking speed transition occurred was distinct from those prior- and post- transition, with on average 0.15 m shorter step lengths, 3.6° more hip flexion, and 3.3° more dorsiflexion during stance. We also found that peak hip flexion occurred 22% later, and peak hip extension (39%), knee flexion (26%), and dorsiflexion (44%) occurred earlier in stance for both typical to slower and typical to faster walking. Older adults had altered timing of peak joint angles compared with younger adults across both acceleration and deceleration conditions, indicating age-dependent responses to changing walking speed. Our findings are an important first step in establishing values for kinematics during walking speed transitions in younger and typical older adults.

Impact of Magnesium on Oxytocin Receptor Function

BACKGROUND AND PURPOSE

The intranasal administration of oxytocin (OT) reduces migraine headaches through activation of the oxytocin receptor (OTR). Magnesium ion (Mg2+) concentration is critical to the activation of the OTR, and a low serum Mg2+ concentration is predictive of a migraine headache. We, therefore, examined the functional impact of Mg2+ concentration on OT-OTR binding efficacy using two complimentary bioassays.

EXPERIMENTAL APPROACH

Current clamp recordings of rat trigeminal ganglia (TG) neurons measured the impact of Mg2+ on an OT-induced reduction in excitability. In addition, we assessed the impact of Mg2+ on intranasal OT-induced craniofacial analgesia in rats.

KEY RESULTS

While OT alone dose-dependently hyperpolarized TG neurons, decreasing their excitability, the addition of 1.75 mM Mg2+ significantly enhanced this effect. Similarly, while the intranasal application of OT produced dose-dependent craniofacial analgesia, Mg2+ significantly enhanced these effects.

CONCLUSIONS AND IMPLICATIONS

OT efficacy may be limited by low ambient Mg2+ levels. The addition of Mg2+ to OT formulations may improve its efficacy in reducing headache pain as well as for other OT-dependent processes.

Feasibility of transcutaneous spinal direct current stimulation combined with locomotor training after spinal cord injury

Study Design:

Feasibility study, consisting of random-order, cross-over study of a single intervention session, followed by a parallel-arm study of 16 sessions

Objectives:

To investigate the feasibility of a novel combinatorial approach with simultaneous delivery of transcutaneous spinal direct current stimulation (tsDCS) and locomotor training (tsDCS+LT) after spinal cord injury, compared to sham stimulation and locomotor training (sham+LT), and examine preliminary effects on walking function.

Setting:

Clinical research center in the southeastern United States

Methods:

Eight individuals with chronic incomplete spinal cord injury (ISCI) completed the two-part protocol. Feasibility was assessed based on safety (adverse responses), tolerability (pain, spasticity, skin integrity), and protocol achievement (session duration, intensity). Walking function was assessed with the 10-meter and 6-minute walk tests.

Results:

There were no major adverse responses. Minimal reports of skin irritation and musculoskeletal pain were consistent between groups. Average training peak heart rate as percent of maximum (mean(SD); tsDCS+LT: 66(4)%, sham+LT: 69(10)%) and Borg ratings of perceived exertion (tsDCS+LT: 17.5(1.2), sham+LT: 14.4(1.8)) indicate both groups trained at high intensities. Walking speed gains exceeded the minimal clinically important difference (MCID) in three of four who received tsDCS+LT (0.18(0.29) m/s) and one of four in sham+LT (−0.05(0.23) m/s). Gains in walking endurance exceeded the MCID in one of four in each group (tsDCS+LT: 36.4(69.0) m, sham+LT: 4.9(56.9) m).

Conclusions:

Combinatorial tsDCS and locomotor training is safe and feasible for individuals with chronic ISCI, even those with considerable walking impairment. Study outcomes support the need to investigate the efficacy of this approach.

Enhancing Locomotor Learning With Transcutaneous Spinal Electrical Stimulation and Somatosensory Augmentation: A Pilot Randomized Controlled Trial in Older Adults

This study investigated locomotor learning of a complex terrain walking task in older adults, when combined with two adjuvant interventions: transcutaneous spinal direct current stimulation (tsDCS) to increase lumbar spinal cord excitability, and textured shoe insoles to increase somatosensory feedback to the spinal cord. The spinal cord has a crucial contribution to control of walking, and is a novel therapeutic target for rehabilitation of older adults. The complex terrain task involved walking a 10-meter course consisting of nine obstacles and three sections of compliant (soft) walking surface. Twenty-three participants were randomly assigned to one of the following groups: sham tsDCS and smooth insoles (sham/smooth; control group), sham tsDCS and textured insoles (sham/textured), active tsDCS and smooth insoles (active/smooth), and active tsDCS and textured insoles (active/textured). The first objective was to assess the feasibility, tolerability, and safety of the interventions. The second objective was to assess preliminary efficacy for increasing locomotor learning, as defined by retention of gains in walking speed between a baseline visit of task practice, and a subsequent follow-up visit. Variability of the center of mass while walking over the course was also evaluated. The change in executive control of walking (prefrontal cortical activity) between the baseline and follow-up visits was measured with functional near infrared spectroscopy. The study results demonstrated feasibility based on enrollment and retention of participants, tolerability based on self-report, and safety based on absence of adverse events. Preliminary efficacy was supported based on trends showing larger gains in walking speed and more pronounced reductions in mediolateral center of mass variability at the follow-up visit in the groups randomized to active tsDCS or textured insoles. These data justify future larger studies to further assess dosing and efficacy of these intervention approaches. In conclusion, rehabilitation interventions that target spinal control of walking present a potential opportunity for enhancing walking function in older adults.

SARS-CoV-2 enzyme-linked immunosorbent assays as proxies for plaque reduction neutralisation tests

Severe acute respiratory coronavirus 2 (SARS-CoV-2) has spread globally since its emergence in 2019. Most SARS-CoV-2 infections generate immune responses leading to rising levels of immunoglobulins (Ig) M, A and G which can be detected using diagnostic tests including enzyme-linked immunosorbent assays (ELISA). Whilst implying previous SARS-CoV-2 infection, the detection of Ig by ELISA does not guarantee the presence of neutralising antibodies (NAb) that can prevent the virus infecting cells. Plaque reduction neutralisation tests (PRNT) detect NAb, but are not amenable to mass testing as they take several days and require use of SARS-CoV-2 in high biocontainment laboratories. We evaluated the ability of IgG and IgM ELISAs targeting SARS-CoV-2 spike subunit 1 receptor binding domain (S1-RBD), and spike subunit 2 (S2) and nucleocapsid protein (NP), at predicting the presence and magnitude of NAb determined by PRNT. IgG S2 + NP ELISA was 96.8% [95% CI 83.8-99.9] sensitive and 88.9% [95% CI 51.8-99.7] specific at predicting the presence of NAbs (PRNT₈₀ > 1:40). IgG and IgM S1-RBD ELISAs correlated with PRNT titre, with higher ELISA results increasing the likelihood of a robust neutralising response. The IgM S1-RBD assay can be used as a rapid, high throughput test to approximate the magnitude of NAb titre.

Long-term mortality in asymptomatic patients with stable ischemic heart disease undergoing percutaneous coronary intervention

OBJECTIVES

Patients with stable ischemic heart disease (SIHD) may present with a variety of symptoms including typical angina, angina equivalents such as dyspnea or no symptoms. We sought to determine whether symptom status affects periprocedural safety and long-term mortality in patients undergoing PCI.

METHODS

Prospectively enrolled consecutive patients undergoing PCI for SIHD at six hospitals in Australia between 2005 to 2018 as part of the Melbourne Interventional Group registry. Symptom status was recorded at the time of PCI and patients undergoing staged PCI were excluded.

RESULTS

Overall, 11,730 patients with SIHD were followed up for a median period of 5 years (maximum 14.0 years, interquartile range 2.2-9.0 years) with 1,317 (11.2%) being asymptomatic. Asymptomatic patients were older, and more likely to be male, have triple-vessel disease, with multiple comorbidities including renal failure, diabetes and heart failure (all P < .01). These patients had significantly higher rates of periprocedural complications and major adverse cardiovascular events at 30-days. Long-term mortality was significantly higher in asymptomatic patients (27.2% vs 18.0%, P < .001). On cox regression for long-term mortality, after adjustment for more important clinical variables, asymptomatic status was an independent predictor (Hazard ratio (HR) 1.39 95% CI 1.16-1.66, P < .001).

CONCLUSIONS

In a real-world cohort of patients undergoing revascularization for SIHD, absence of symptoms was associated with higher rates of periprocedural complications and, after adjustment for more important clinical variables, was an independent predictor of long-term mortality. As the primary goal of revascularization in SIHD remains angina relief, the appropriateness of PCI in the absence of symptoms warrants justification.

A systematic genome-wide account of binding sites for the model transcription factor Gcn4

Sequence-specific DNA-binding transcription factors are central to gene regulation. They are often associated with consensus binding sites that predict far more genomic sites than are bound in vivo. One explanation is that most sites are blocked by nucleosomes, such that only sites in nucleosome-depleted regulatory regions are bound. We compared the binding of the yeast transcription factor Gcn4 in vivo using published ChIP-seq data (546 sites) and in vitro, using a modified SELEX method (“G-SELEX”), which utilizes short genomic DNA fragments to quantify binding at all sites. We confirm that Gcn4 binds strongly to an AP-1-like sequence (TGACTCA) and weakly to half-sites. However, Gcn4 binds only some of the 1078 exact matches to this sequence, even in vitro. We show that there are only 166 copies of the high-affinity RTGACTCAY site (exact match) in the yeast genome, all occupied in vivo, largely independently of whether they are located in nucleosome-depleted or nucleosomal regions. Generally, RTGACTCAR/YTGACTCAY sites are bound much more weakly and YTGACTCAR sites are unbound, with biological implications for determining induction levels. We conclude that, to a first approximation, Gcn4 binding can be predicted using the high-affinity site, without reference to chromatin structure. We propose that transcription factor binding sites should be defined more precisely using quantitative data, allowing more accurate genome-wide prediction of binding sites and greater insight into gene regulation.

Abstract IA-003: Proteogenomic characterizations of pancreatic ductal adenocarcinoma

Pancreatic cancer is one of the deadliest cancers and the five-year survival rate is less than 10%. Pancreatic ductal adenocarcinoma (PDAC) represents more than 90% of all pancreatic malignancies, and is responsible for the majority of pancreatic cancer-related deaths. Towards understanding the underlying molecular alterations that drive PDAC oncogenesis and identify therapeutic targets for personalized treatments, we comprehensively characterized 140 pancreatic cancers and 67 normal adjacent tissues. To ensure robust, downstream analyses, tumor neoplastic cellularity was assessed via multiple, orthogonal strategies using molecular features, and verified via pathological estimation of tumor cellularity based on histological review to select tumors with sufficient tumor cellularity. We also included the analysis of 9 normal pancreatic ductal tissues. Proteomic, phosphoproteomic, and glycoproteomic analyses were used to characterize proteins and their modifications. In addition, whole genome sequencing, whole exome sequencing, methylation, RNA-seq, and miRNA-seq were performed on the same tissues to facilitate an integrated proteogenomic analysis and determine the impact of genomic alterations on protein expression, signaling pathways, and post-translational modifications. These characterizations revealed functional impacts of genomic and epigenomic alterations on proteins and protein modifications, delineated PDAC cell microenvironment compositions and the immune signatures for immunotherapy, also uncovered putative kinase inhibitors that could be tested for therapy. This integrated proteogenomic characterization of PDAC will serve as a valuable resource for the community, paving the way for early detection and identification of novel therapeutic targets.

Citation Format: Liwei Cao, Chen Huang, Daniel Cui Zhou, Yingwei Hu, Mamie Lih, Sara R. Savage, Karsten Krug, David J. Clark, Michael Schnaubelt, Lijun Chen, Felipe da Veiga Leprevost, Rodrigo Vargas Eguez, Alexey I. Nesvizhskii, D.R. Mani, Gilbert S. Omenn, Emily S. Boja, Mehdi Mesri, Ana I. Robles, Henry Rodriguez, Oliver F. Bathe, Daniel W. Chan, Ralph H. Hruban, Li Ding, Bing Zhang, Hui Zhang, Clinical Proteomic Tumor Analysis Consortium. Proteogenomic characterizations of pancreatic ductal adenocarcinoma [abstract]. In: Proceedings of the AACR Virtual Special Conference on Pancreatic Cancer; 2021 Sep 29-30. Philadelphia (PA): AACR; Cancer Res 2021;81(22 Suppl):Abstract nr IA-003.

Proteogenomic characterization of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive cancer with poor patient survival. Toward understanding the underlying molecular alterations that drive PDAC oncogenesis, we conducted comprehensive proteogenomic analysis of 140 pancreatic cancers, 67 normal adjacent tissues, and 9 normal pancreatic ductal tissues. Proteomic, phosphoproteomic, and glycoproteomic analyses were used to characterize proteins and their modifications. In addition, whole-genome sequencing, whole-exome sequencing, methylation, RNA sequencing (RNA-seq), and microRNA sequencing (miRNA-seq) were performed on the same tissues to facilitate an integrated proteogenomic analysis and determine the impact of genomic alterations on protein expression, signaling pathways, and post-translational modifications. To ensure robust downstream analyses, tumor neoplastic cellularity was assessed via multiple orthogonal strategies using molecular features and verified via pathological estimation of tumor cellularity based on histological review. This integrated proteogenomic characterization of PDAC will serve as a valuable resource for the community, paving the way for early detection and identification of novel therapeutic targets.

Rehabilitation with accurate adaptability walking tasks or steady state walking: A randomized clinical trial in adults post-stroke

OBJECTIVE

To assess changes in walking function and walking-related prefrontal cortical activity following two post-stroke rehabilitation interventions: an accurate adaptability (ACC) walking intervention and a steady state (SS) walking intervention.

DESIGN

Randomized, single blind, parallel group clinical trial.

SETTING

Hospital research setting.

SUBJECTS

Adults with chronic post-stroke hemiparesis and walking deficits.

INTERVENTIONS

ACC emphasized stepping accuracy and walking adaptability, while SS emphasized steady state, symmetrical stepping. Both included 36 sessions led by a licensed physical therapist. ACC walking tasks recruit cortical regions that increase corticospinal tract activation, while SS walking activates the corticospinal tract less intensely.

MAIN MEASURES

The primary functional outcome measure was preferred steady state walking speed. Prefrontal brain activity during walking was measured with functional near infrared spectroscopy to assess executive control demands. Assessments were conducted at baseline, post-intervention (three months), and follow-up (six months).

RESULTS

Thirty-eight participants were randomized to the study interventions (mean age 59.6 ± 9.1 years; mean months post-stroke 18.0 ± 10.5). Preferred walking speed increased from baseline to post-intervention by 0.13 ± 0.11 m/s in the ACC group and by 0.14 ± 0.13 m/s in the SS group. The Time × Group interaction was not statistically significant (P = 0.86). Prefrontal fNIRS during walking decreased from baseline to post-intervention, with a marginally larger effect in the ACC group (P = 0.05).

CONCLUSIONS

The ACC and SS interventions produced similar changes in walking function. fNIRS suggested a potential benefit of ACC training for reducing demand on prefrontal (executive) resources during walking.

SMARTphone-based, early cardiac REHABilitation in patients with acute coronary syndromes: a randomized controlled trial

BACKGROUND

There are well-documented treatment gaps in secondary prevention of coronary heart disease with a lack of clearly defined strategies to assist early physical activity after acute coronary syndromes (ACS). Smartphone technology may provide an innovative platform to close these gaps.

OBJECTIVES

The primary goal of this study was to assess whether a smartphone-based, early cardiac rehabilitation program improved exercise capacity in patients with ACS.

METHODS

A total of 206 patients with ACS across six tertiary Australian hospitals were included in this randomized controlled trial. Participants were randomized to usual care (UC; including referral to traditional cardiac rehabilitation), with or without an adjunctive smartphone-based cardiac rehabilitation program (S-CRP) upon hospital discharge. The primary endpoint was change in exercise capacity, measured by the change in 6-minute walk test distance at 8 weeks when compared to baseline, between groups. Secondary endpoints included uptake and adherence to cardiac rehabilitation, changes in cardiac risk factors, psychological well-being and quality of life status.

RESULTS

Of the 168 patients with complete follow-up (age 56 ± 10 years; 16% females), 83 were in the S-CRP. At 8-week follow-up, the S-CRP group had a clinically significant improvement in 6-minute walk test distance (Δ117 ± 76 vs. Δ91 ± 110 m; P = 0.02). Patients in the S-CRP were more likely to participate (87% vs. 51%, P < 0.001) and adhere (72% vs. 22%, P < 0.001) to a cardiac rehabilitation program. Compared to UC, patients receiving S-CRP had similar smoking cessation rates, LDL-cholesterol levels, blood pressure reduction, depression, anxiety and quality of life measures (all P = NS).

CONCLUSION

In patients with ACS, a S-CRP, as an adjunct to UC improved exercise capacity at 8 weeks in addition to participation and adherence to cardiac rehabilitation (Australian New Zealand Clinical Trials Registry; ACTRN12616000426482).

Unbiased Proteomic and Phosphoproteomic Analysis Identifies Response Signatures and Novel Susceptibilities After Combined MEK and mTOR Inhibition in BRAFV600E Mutant Glioma

The mitogen-activated protein kinase pathway is one of the most frequently altered pathways in cancer. It is involved in the control of cell proliferation, invasion, and metabolism, and can cause resistance to therapy. A number of aggressive malignancies, including melanoma, colon cancer, and glioma, are driven by a constitutively activating missense mutation (V600E) in the v-Raf murine sarcoma viral oncogene homolog B (BRAF) component of the pathway. Mitogen-activated protein kinase kinase (MEK) inhibition is initially effective in targeting these cancers, but reflexive activation of mammalian target of rapamycin (mTOR) signaling contributes to frequent therapy resistance. We have previously demonstrated that combination treatment with the MEK inhibitor trametinib and the dual mammalian target of rapamycin complex 1/2 inhibitor TAK228 improves survival and decreases vascularization in a BRAFV600E mutant glioma model. To elucidate the mechanism of action of this combination therapy and understand the ensuing tumor response, we performed comprehensive unbiased proteomic and phosphoproteomic characterization of BRAFV600E mutant glioma xenografts after short-course treatment with trametinib and TAK228. We identified 13,313 proteins and 30,928 localized phosphosites, of which 12,526 proteins and 17,444 phosphosites were quantified across all samples (data available via ProteomeXchange; identifier PXD022329). We identified distinct response signatures for each monotherapy and combination therapy and validated that combination treatment inhibited activation of the mitogen-activated protein kinase and mTOR pathways. Combination therapy also increased apoptotic signaling, suppressed angiogenesis signaling, and broadly suppressed the activity of the cyclin-dependent kinases. In response to combination therapy, both epidermal growth factor receptor and class 1 histone deacetylase proteins were activated. This study reports a detailed (phospho)proteomic analysis of the response of BRAFV600E mutant glioma to combined MEK and mTOR pathway inhibition and identifies new targets for the development of rational combination therapies for BRAF-driven tumors.

High-Throughput Analyses of Glycans, Glycosites, and Intact Glycopeptides Using C4-and C18/MAX-Tips and Liquid Handling System

Protein glycosylation is one of the most common and diverse modifications. Aberrant protein glycosylation has been reported to associate with various diseases. High‐throughput and comprehensive characterization of glycoproteins is crucial for structural and functional studies of altered glycosylation in biological, physiological, and pathological processes. In this protocol, we detail a workflow for comprehensive analyses of intact glycopeptides (IGPs), glycosylation sites, and glycans from N‐linked glycoproteins. By utilizing liquid handling systems, our workflow could enrich IGPs in a high‐throughput manner while reducing sample processing time and human error involved in traditional proteomics sample processing techniques. Together, our workflow enables a high‐throughput enrichment of glycans, glycosites, and intact glycopeptides from complex biological or clinical samples. © 2021 The Authors. Current Protocols published by Wiley Periodicals LLC.

Basic Protocol 1: Enzymatic digestion of glycoproteins using C4‐tips

Basic Protocol 2: Intact glycopeptide analysis using C18/MAX‐tips

Basic Protocol 3: Glycan and glycosite analysis

Chronic Pain is Associated With Reduced Sympathetic Nervous System Reactivity During Simple and Complex Walking Tasks: Potential Cerebral Mechanisms

Background

Autonomic dysregulation may lead to blunted sympathetic reactivity in chronic pain states. Autonomic responses are controlled by the central autonomic network (CAN). Little research has examined sympathetic reactivity and associations with brain CAN structures in the presence of chronic pain; thus, the present study aims to investigate how chronic pain influences sympathetic reactivity and associations with CAN brain region volumes.

Methods

Sympathetic reactivity was measured as change in skin conductance level (ΔSCL) between a resting reference period and walking periods for typical and complex walking tasks (obstacle and dual-task). Participants included 31 people with (n = 19) and without (n = 12) chronic musculoskeletal pain. Structural 3 T MRI was used to determine gray matter volume associations with ΔSCL in regions of the CAN (i.e., brainstem, amygdala, insula, and anterior cingulate cortex).

Results

ΔSCL varied across walking tasks (main effect p = 0.036), with lower ΔSCL in chronic pain participants compared to controls across trials 2 and 3 under the obstacle walking condition. ΔSCL during typical walking was associated with multiple CAN gray matter volumes, including brainstem, bilateral insula, amygdala, and right caudal anterior cingulate cortex (p’s < 0.05). The difference in ΔSCL from typical-to-obstacle walking were associated with volumes of the midbrain segment of the brainstem and anterior segment of the circular sulcus of the insula (p’s < 0.05), with no other significant associations. The difference in ΔSCL from typical-to-dual task walking was associated with the bilateral caudal anterior cingulate cortex, and left rostral cingulate cortex (p’s < 0.05).

Conclusions

Sympathetic reactivity is blunted during typical and complex walking tasks in persons with chronic pain. Additionally, blunted sympathetic reactivity is associated with CAN brain structure, with direction of association dependent on brain region. These results support the idea that chronic pain may negatively impact typical autonomic responses needed for walking performance via its potential impact on the brain.

Cardiovascular mortality following liver transplantation: predictors and temporal trends over 30 years

AIMS

There has been significant evolution in operative and post-transplant therapies following liver transplantation (LT). We sought to study their impact on cardiovascular (CV) mortality, particularly in the longer term.

METHODS AND RESULTS

A retrospective cohort study was conducted of all adult LTs in Australia and New Zealand across three 11-year eras from 1985 to assess prevalence, modes, and predictors of early (≤30 days) and late (>30 days) CV mortality. A total of 4265 patients were followed-up for 37 409 person-years. Overall, 1328 patients died, and CV mortality accounted for 228 (17.2%) deaths. Both early and late CV mortality fell significantly across the eras (P < 0.001). However, CV aetiologies were consistently the leading cause of early mortality and accounted for ∼40% of early deaths in the contemporary era. Cardiovascular deaths occurred significantly later than non-cardiac aetiologies (8.8 vs. 5.2 years, P < 0.001). On multivariable Cox regression, coronary artery disease [hazard ratio (HR) 4.6, 95% confidence interval (CI) 1.2-21.6; P = 0.04] and era of transplantation (HR 0.44; 95% CI 0.28-0.70; P = 0.01) were predictors of early CV mortality, while advancing age (HR 1.05, 95% CI 1.02-1.10; P = 0.005) was an independent predictors of late CV mortality. Most common modes of CV death were cardiac arrest, cerebrovascular events, and myocardial infarction.

CONCLUSION

Despite reductions in CV mortality post-LT over 30 years, they still account for a substantial proportion of early and late deaths. The late occurrence of CV deaths highlights the importance of longitudinal follow-up to study the efficacy of targeted risk-reduction strategies in this unique patient population.

Abstract 15: Confirmatory integrated proteogenomic characterization of clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) is the most predominant histology of renal cell carcinoma (RCC), representing 75% of all RCC cases and accounting for the majority of associated deaths. Previously, the Clinical Proteomics Tumor Analysis Consortium (CPTAC) leveraged a proteogenomic approach to characterize a cohort of 103 ccRCC tumors and 80 paired normal adjacent tissue (NAT) samples to better understand the impact of genomic alterations on the functional modules that drive ccRCC tumorigenesis. Results of our report included delineating chromosomal translocations as a possible mechanism for 3p loss in ccRCC, detecting phospho-substrate targets for FDA-approved kinase inhibitors, and identifying four immune-based subtypes of ccRCC. In this report, we sought to verify these initial findings in an independent cohort comprised of 112 RCC tumors and 87 paired NAT samples. Leveraging data-independent acquisition mass spectrometry based proteomic strategies with comprehensive genomic and transcriptomic analyses, we integrated proteomic and phosphoproteomic analyses with genomic, epigenomic, microRNA, and transcriptomic data for tumor and NAT samples in a confirmatory cohort to elucidate the dysregulated cellular mechanism resulting from genomic alterations. We observed a high degree of concordance of genomic and transcriptomic signatures, as well as comparable tumor microenvironment cell compositions in this confirmatory cohort with our previous discovery cohort, indicating that many of the molecular characteristics defined in our first report are robustly maintained. Proteomic characterization identified protein profiles associated with disparate genomic alterations associated with ccRCC, as well as protein features specific to the four immune-based subtypes of ccRCC: CD8+ Inflamed, CD8- Inflamed, VEGF Immune Desert, and Metabolic Immune Desert. Investigation of the impact of FDA-approved kinase inhibitors, prioritized by our phosphoproteomic results, allowed for the examination of the functional consequences of these therapies respective to their mechanisms of action in ccRCC cells via the targeting of ERK/MAPK and PI3K/AKT signaling pathways, and G2/M cell cycle regulation. Finally, we explored the degree of intratumor heterogeneity of ccRCC at the genomic, transcriptomic, and proteomic levels, revealing molecular profiles that were maintained or altered in distinct regions of tumors, and further linked these molecular signatures to observed histopathological features. Overall, our study advances our understanding of functional consequences of the genomic alterations on gene and protein expression as well as subsequent cell signaling pathways related to targets for potential new therapeutic intervention, while further supporting the rationale for integrating multi-level “omics” analyses to characterize the proteogenomic landscape of ccRCC pathobiology.

Citation Format: David J. Clark, Yize Li, Clinical Proteomic Tumor Analysis Consortium. Confirmatory integrated proteogenomic characterization of clear cell renal cell carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 15.

Prevalence of neutralising antibodies against SARS-CoV-2 in acute infection and convalescence: A systematic review and meta-analysis

BACKGROUND

Individuals infected with SARS-CoV-2 develop neutralising antibodies. We investigated the proportion of individuals with SARS-CoV-2 neutralising antibodies after infection and how this proportion varies with selected covariates.

METHODOLOGY/PRINCIPAL FINDINGS

This systematic review and meta-analysis examined the proportion of individuals with SARS-CoV-2 neutralising antibodies after infection and how these proportions vary with selected covariates. Three models using the maximum likelihood method assessed these proportions by study group, covariates and individually extracted data (protocol CRD42020208913). A total of 983 reports were identified and 27 were included. The pooled (95%CI) proportion of individuals with neutralising antibodies was 85.3% (83.5-86.9) using the titre cut off >1:20 and 83.9% (82.2-85.6), 70.2% (68.1-72.5) and 54.2% (52.0-56.5) with titres >1:40, >1:80 and >1:160, respectively. These proportions were higher among patients with severe COVID-19 (e.g., titres >1:80, 84.8% [80.0-89.2], >1:160, 74.4% [67.5-79.7]) than those with mild presentation (56.7% [49.9-62.9] and 44.1% [37.3-50.6], respectively) and lowest among asymptomatic infections (28.6% [17.9-39.2] and 10.0% [3.7-20.1], respectively). IgG and neutralising antibody levels correlated poorly.

CONCLUSIONS/SIGNIFICANCE

85% of individuals with proven SARS-CoV-2 infection had detectable neutralising antibodies. This proportion varied with disease severity, study setting, time since infection and the method used to measure antibodies.

Abstract 324: Unbiased proteomic and phosphoproteomic analysis identifies response signatures and novel susceptibilities after combined MEK and mTOR inhibition in BRAFV600E mutant glioma

The mitogen-activated protein kinase (MAPK) pathway is one of the most frequently altered pathways in cancer. It is involved in the control of cell proliferation, invasion, metabolism, and can cause resistance to therapy. A number of aggressive malignancies including melanoma, colon cancer, and glioma, are driven by a constitutively activating missense mutation (V600E) in the BRAF component of the pathway. MEK inhibition is initially effective in targeting these cancers, but reflexive activation of mTOR signaling contributes to frequent therapy resistance. We have previously demonstrated that combination treatment with the MEK inhibitor trametinib and the dual mTORC1/2 inhibitor TAK228 improves survival and decreases vascularization in a BRAFV600E mutant glioma model. To elucidate the mechanism of action of this combination therapy and understand the ensuing tumor response, we performed comprehensive unbiased proteomic and phosphoproteomic characterization of BRAFV600E mutant glioma xenografts after short-course treatment with trametinib and TAK228. We identified 13,313 proteins and 30,928 localized phosphosites, of which 12,526 proteins and 17,444 phosphosites were quantified across all samples (data available via ProteomeXchange; identifier PXD022329). We identified distinct response signatures for each monotherapy and combination therapy and validated that combination treatment inhibited activation of the MAPK and mTOR pathways. Combination therapy also increased apoptotic signaling, suppressed angiogenesis signaling, and broadly suppressed the activity of the cyclin-dependent kinases. In addition, combination therapy had a profound impact on cancer cell metabolic pathways, increasing the expression of proteins (and their activating phosphorylations) involved in glycolysis, the tricarboxylic acid (TCA) cycle, nucleotide biosynthesis, and DNA replication. In response to combination therapy, both receptor tyrosine kinase and histone deacetylase proteins were activated. This study reports a detailed (phospho)proteomic analysis of the response of BRAFV600E mutant glioma to combined MEK and mTOR pathway inhibition and identifies new targets for the development of rational combination therapies for aggressive BRAF-driven tumors.

Citation Format: Micah J. Maxwell, Antje Arnold, Heather Sweeney, Ljun Chen, Tung-Shing M. Lih, Michael Schnaubelt, Charles G. Eberhart, Jeffrey A. Rubens, Hui Zhang, David J. Clark, Eric H. Raabe. Unbiased proteomic and phosphoproteomic analysis identifies response signatures and novel susceptibilities after combined MEK and mTOR inhibition in BRAFV600E mutant glioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 324.

Comparison of Long-Term Outcomes After Percutaneous Coronary Intervention in Patients With Insulin-Treated Versus Non-Insulin Treated Diabetes Mellitus

There are conflicting data on whether patients with insulin-treated diabetes mellitus (ITDM) have poorer outcomes compared with non-insulin treated diabetic (non-ITDM) patients following percutaneous coronary intervention (PCI). We therefore compared clinical outcomes following PCI in ITDM versus non-ITDM patients. We prospectively collected data on 4,579 patients with diabetes underwent PCI between 2005 and 2014 in a large multicenter registry and dichotomized them as having ITDM (n = 1,111) or non-ITDM (n = 3,468). The non-ITDM group was further divided into diet control only (diet-DM; n = 786) and those taking oral hypoglycemic agents (OHG-DM; n = 2,639), and clinical outcomes were compared with ITDM patients. Median follow-up for long-term mortality was 4.2 years (IQR 2.0 to 6.6 years). ITDM patients were more likely to be female, obese, and have severe renal impairment (all p <0.001). Procedural characteristics were similar other than a greater use of drug-eluting stents in ITDM patients. On multivariable analysis, ITDM was an independent predictor of 12-month major adverse cardiovascular and cerebrovascular events (MACCE; OR 1.26, 95% CI 1.02 to1.55, p = 0.03). Dividing the non-ITDM group further by treatment, a progressively higher rate of 12-month MACCE across the 3 groups was observed (13.5% vs 17.9% vs 21.8%; p <0.001). Long-term mortality was similar in the diet-DM and OHG-DM groups, but significantly higher in the ITDM group on Kaplan-Meier analysis (log-rank p <0.001). In conclusion, there is a clear gradient of adverse outcomes with escalation of therapy from diet control to OHGs to insulin.

Brain activity during walking in older adults: Implications for compensatory versus dysfunctional accounts

A prominent trend in the functional brain imaging literature is that older adults exhibit increased brain activity compared to young adults to perform a given task. This phenomenon has been extensively studied for cognitive tasks, with the field converging on interpretations described in two alternative accounts. One account interprets over-activation in older adults as reflecting neural dysfunction (increased brain activity - indicates poorer performance), whereas another interprets it as neural compensation (increased brain activity - supports better performance). Here we review studies that have recorded brain activity and walking measurements in older adults, and we categorize their findings as reflecting either neural dysfunction or neural compensation. Based on this synthesis, we recommend including multiple task difficulty levels in future work to help differentiate if and when compensation fails as the locomotion task becomes more difficult. Using multiple task difficulty levels with neuroimaging will lead to a more advanced understanding of how age-related changes in locomotor brain activity fit with existing accounts of brain aging and support the development of targeted neural rehabilitation techniques.

Accuracy of the Mologic COVID-19 rapid antigen test: a prospective multi-centre analytical and clinical evaluation

Background: The coronavirus disease 2019 (COVID-19) pandemic has highlighted the reliance on antigen detection rapid diagnostic tests (Ag-RDTs). Their evaluation at point of use is a priority. Methods: Here, we report a multi-centre evaluation of the analytical sensitivity, specificity, and clinical accuracy of the Mologic COVID-19 Ag-RDT by comparing to reverse transcriptase polymerase chain reaction (RT-qPCR) results from individuals with and without COVID-19 symptoms. Participants had attended hospitals in Merseyside, hospital and ambulance services in Yorkshire, and drive-through testing facilities in Northumberland, UK. Results: The limit of detection of the Mologic COVID-19 Ag-RDT was 5.0 x 102 pfu/ml in swab matrix with no cross-reactivity and interference for any other pathogens tested. A total of 347 participants were enrolled from 26th of November 2020 to 15th of February 2021 with 39.2% (CI 34.0-44.6) testing RT-qPCR positive for SARS-CoV-2. The overall sensitivity and specificity of the Mologic Ag-RDT compared to the reference SARS-CoV-2 RT-qPCR were 85.0% (95% CI 78.3-90.2) and 97.8% (95.0-99.3), respectively. Sensitivity was stratified by RT-qPCR cycle threshold (Ct) and 98.4% (91.3-100) of samples with a Ct less than 20 and 93.2% (86.5-97.2) of samples with a Ct less than 25 were detected using the Ag-RDT. Clinical accuracy was stratified by sampling strategy, swab type and clinical presentation. Mologic COVID-19 Ag-RDT demonstrated highest sensitivity with nose/throat swabs compared with throat or nose swabs alone; however, the differences were not statistically significant. Conclusions: Overall, the Mologic test had high diagnostic accuracy across multiple different settings, different demographics, and on self-collected swab specimens. These findings suggest the Mologic rapid antigen test may be deployed effectively across a range of use settings.