Citations

AbstractAimIn contrast to knowledge that heart failure (HF) patients demonstrate peak exercise uncoupling across ventilation, gas exchange and cardiac haemodynamics, whether this dyssynchrony follows that at the exercise on‐transition is unclear. This study tested whether exercise on‐transition temporal lag for ventilation relative to gas exchange and oxygen pulse (O2pulse) couples with effects from abnormal pulmonary gaseous oxygen store (O2store) contributions to O2 to interdependently precipitate persistently elevated ventilatory demand and low oxidative metabolic capacity in HF.MethodsBeat‐to‐beat HR and breath‐to‐breath ventilation and gas exchange were continuously acquired in HF (N = 9, ejection fraction = 30 ± 9%) and matched controls (N = 10) during square‐wave ergometry at 60% O2peak (46 ± 14 vs 125 ± 54‐W, P < .001). Temporal responses across E, O2 and O2pulse were assessed for the exercise on‐transition using single exponential model Phase II on‐kinetic time constants (τ = time to reach 63% steady‐state rise). Breath‐to‐breath gas fractions and respiratory flows were used to determine O2stores.ResultsHF vs controls: τ for E (137 ± 93 vs 74 ± 40‐seconds, P = .03), O2 (60 ± 40 vs 23 ± 5‐seconds, P = .03) and O2pulse (28 ± 18 vs 23 ± 15‐seconds, P = .59). Within HF, τ for E differed from O2pulse (P < .02), but not O2. Exercise E rise (workload indexed) differed in HF vs controls (545 ± 139 vs 309 ± 88‐mL min−1 W−1, P < .001). Exercise on‐transition O2store depletion in HF exceeded controls, generally persisting to end‐exercise.ConclusionThese data suggest HF demonstrated exercise on‐transition O2store depletion (high O2store contribution to O2) coupled with dyssynchronous E, O2 and O2pulse kinetics—not attributable to prolonged cardiac haemodynamics. Persistent high ventilatory demand and low oxidative metabolic capacity in HF may be precipitated by physiological uncoupling occurring within the exercise on‐transition.

PurposeTo build and evaluate a small‐footprint, lightweight, high‐performance 3T MRI scanner for advanced brain imaging with image quality that is equal to or better than conventional whole‐body clinical 3T MRI scanners, while achieving substantial reductions in installation costs.MethodsA conduction‐cooled magnet was developed that uses less than 12 liters of liquid helium in a gas‐charged sealed system, and standard NbTi wire, and weighs approximately 2000 kg. A 42‐cm inner‐diameter gradient coil with asymmetric transverse axes was developed to provide patient access for head and extremity exams, while minimizing magnet‐gradient interactions that adversely affect image quality. The gradient coil was designed to achieve simultaneous operation of 80‐mT/m peak gradient amplitude at a slew rate of 700 T/m/s on each gradient axis using readily available 1‐MVA gradient drivers.ResultsIn a comparison of anatomical imaging in 16 patients using T2‐weighted 3D fluid‐attenuated inversion recovery (FLAIR) between the compact 3T and whole‐body 3T, image quality was assessed as equivalent to or better across several metrics. The ability to fully use a high slew rate of 700 T/m/s simultaneously with 80‐mT/m maximum gradient amplitude resulted in improvements in image quality across EPI, DWI, and anatomical imaging of the brain.ConclusionsThe compact 3T MRI system has been in continuous operation at the Mayo Clinic since March 2016. To date, over 200 patient studies have been completed, including 96 comparison studies with a clinical 3T whole‐body MRI. The increased gradient performance has reliably resulted in consistently improved image quality.

PurposeDixon‐based fat suppression has recently gained interest for dynamic contrast‐enhanced MRI, but multi‐echo techniques require longer scan times and reduce temporal resolution compared to single‐echo alternatives without fat suppression. The purpose of this work is to demonstrate accelerated single‐echo Dixon imaging with high spatial and temporal resolution.Theory and MethodsReal‐valued water and fat images can be obtained from a single measurement if the shared initial phase and that due to are assumed known a priori. An expression for simultaneous sensitivity encoding (SENSE) unfolding and fat‐water separation is derived for the general undersampling case, and simplified under the special case of uniform Cartesian undersampling. In vivo experiments were performed in extremities and brain with SENSE acceleration factors of up to R = 8.ResultsSingle‐echo Dixon reconstruction of highly undersampled data was successfully demonstrated. Dynamic contrast‐enhanced water and fat images provided high spatial and temporal resolution dynamic images with image update times shorter than previous single‐echo Dixon work.ConclusionTime‐resolved contrast‐enhanced MRI with single‐echo Dixon fat suppression shows high image quality, improved vessel delineation, and reduced sensitivity to motion when compared to time‐subtraction methods.

Response to a drug often differs widely among individual patients. This variability is frequently observed not only with respect to effective responses but also with adverse drug reactions. Matching patients to the drugs that are most likely to be effective and least likely to cause harm is the goal of effective therapeutics. Pharmacogenomics (PGx) holds the promise of precision medicine through elucidating the genetic determinants responsible for pharmacological outcomes and using them to guide drug selection and dosing. Here we survey the US landscape of research programs in PGx implementation, review current advances and clinical applications of PGx, summarize the obstacles that have hindered PGx implementation, and identify the critical knowledge gaps and possible studies needed to help to address them.

Abstract Background: Mammography (digital 2D or digital 3D/tomosynthesis) is the cornerstone of current screening strategies for breast cancer, but new approaches are needed to further reduce the proportion of cancers diagnosed at advanced stages and more effectively identify those women in need of additional testing and biopsies. Circulating cell-free nucleic acids (cfNAs) shed from tumors, isolated from peripheral blood, and analyzed with ultra-deep and broad sequencing of cancer-associated genes, have great potential for early cancer detection. The ultimate goal is to develop blood cfNA cancer screening tests for use in conjunction with established risk factors and/or radiographic features for improved cancer detection. Development of these tests requires large, well-annotated cohorts of asymptomatic participants with adequate volumes of prediagnostic blood. The STRIVE Study cohort was recently established to train and validate cfNA-based tests for early detection of breast cancer. Eligibility criteria and trial design: The STRIVE Study is a new prospective, multi-ethnic mammography cohort that will recruit 120,000 subjects from 15+ US breast cancer screening centers (including Mayo Clinic and Sutter Health sites). Eligibility criteria require only that a participant has a scheduled routine screening mammogram at a participating center and has not received a biopsy prior to the research blood draw. Participants are recruited within 28 days of screening mammography (digital or tomosynthesis), consent electronically, provide blood samples, and complete an on-line risk factor questionnaire. Participants will be followed for all cancer diagnoses, cancer recurrences, and death for at least 5 years. Pertinent medical record information, imaging findings (including breast density), and follow-up data will be transferred electronically to a central database throughout the study period. Additional blood samples will be collected from participants with abnormal mammogram results, or who are diagnosed with cancer, to document and better understand the evolution of cfNA signals. Recruitment began in February 2017. Primary Aims: To train and validate a cfNA blood-based test to identify breast cancer overall in a cohort of women undergoing screening mammography. Statistical Methods: The study will be divided into a training phase (1/3 of participants) and an independent clinical validation phase (remaining 2/3 of participants). In the training phase, statistical machine learning techniques will be used to develop algorithms incorporating cfNA signals, clinical characteristics, or radiological features. In the validation phase, the prespecified locked algorithm developed from the training phase will be clinically validated in an independent group of women. Contact information for people with a specific interest in the trial: Additional details regarding the STRIVE Study are available on the ClinicalTrials.gov website (NCT03085888). For site-specific questions, please call 844-366-9738 for the Mayo Clinic and 1-855-578-7483 for Sutter Health. Citation Format: Liu MC, Cummings S, Vachon CM, Kerlikowske K, Couch FJ, Morris EA, Olson JE, Polley EC, Conners AL, Ellis RL, Patel B, Maimone IV S, Zhang N, Hamilton S, Clarke CA, Allen BA, Maddala T, Hartman A-R. Development of cell-free nucleic acid-based tests for early detection of breast cancer: The STRIVE study [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr OT3-02-01.

Background and aim Thoracic radiation therapy (XRT) for cancer is associated with the development of significant coronary artery disease that may require coronary artery bypass grafting surgery (CABG). Contemporary acute surgical outcomes and long-term postoperative survival of patients with prior XRT have not been well characterised. Methods This was a retrospective, single-centre study of patients with a history of thoracic XRT who required CABG and who were propensity matched against 141 controls who underwent CABG over the same time period. The objectives were to assess early CABG outcomes and long-term survival in patients with prior XRT. Results Thirty-eight patients with a history of previous thoracic XRT underwent CABG from 1994 to 2013. The median time from XRT exposure to surgery was 7.9 years (IQR: 2.5–18.4 years). Perioperative adverse events were similar in the XRT group and controls; however, there was a trends lower utilisation of internal mammary artery (IMA) grafts in the XRT group (89%vs98%, P=0.13). After a median postoperative follow-up of 5.4 years (IQR 0.9–9.4 years), no difference in long-term all-cause mortality was observed. Conclusion Patients with prior thoracic XRT who undergo CABG have similar long-term all-cause mortality compared with controls. Isolated CABG after thoracic XRT is not associated with higher perioperative complications, but IMA graft use may be limited by prior XRT.

Objective: The purpose of this study was to evaluate injury characteristics by position groups. Design: Prospective, observational study. Setting: A single, major Division I collegiate football program. Participants: All players on a collegiate football program each fall regular season. Independent Variables: Exposure to Division I collegiate football and position groups. Main Outcome Measures: Injury rates (IRs) per 1000 athlete exposures (AEs) and injury rate ratios (IRRs) were calculated and analyzed for all monitored injury variables, which included time in the season, body part, type of injury, game and practice injuries, mechanism of injury, and type of exposure. Results: During the 2012 to 2016 fall regular seasons, there were 200 reported injuries sustained from 48 615 AE. The overall 5-year IR was 4.11 per 1000 AEs (3.57-4.72 95% confidence intervals). Skill players sustained the highest IR in the preseason (IR, 7.56) compared with line (IR, 4.26) and other (IR, 4.10) position groups. In addition, skill players demonstrated a significantly higher IRR compared with the line (IRR, 1.75, P < 0.05) and other (IRR, 1.85, P < 0.05) position groups. Conclusions: Skill players sustained most of their injuries in the preseason, whereas the linemen and other position groups suffered most of their injuries in the first half of the regular season. Skill players demonstrated a significantly higher IR in preseason, noncontact mechanism injuries, and injuries to the upper leg and thigh compared with line and other position groups. Efforts to reduce soft-tissue muscle strains in skill players targeting the preseason may provide one of the best opportunities to significantly decrease current football IRs, whereas efforts to reduce contact exposures may have the greatest effect on concussions and contact mechanism injuries for the other position group. There were no significant differences in IRs between position groups and type of exposure.

Abstract Context With the aging of the population and projected increase in osteoporotic fractures coupled with the declining use of osteoporosis medications, there is a compelling need for new approaches to treat osteoporosis. Given that age-related osteoporosis generally coexists with multiple other comorbidities (e.g., atherosclerosis, diabetes, frailty) that share aging as the leading risk factor, there is growing interest in the “Geroscience Hypothesis,” which posits that manipulation of fundamental aging mechanisms will delay the appearance or severity of multiple chronic diseases because these diseases share aging as the underlying risk factor. In this context, one fundamental aging mechanism that has received considerable attention recently as contributing to multiple age-related morbidities is cellular senescence. This mini-review provides an overview on cellular senescence with a focus on its role in mediating age-related bone loss. Methods This summary is based on the authors’ knowledge of the field supplemented by a PubMed search using the terms “senescence,” “aging,” and “bone.” Results There is compelling evidence from preclinical models and supportive human data demonstrating an increase in senescent cells in the bone microenvironment with aging. These cells produce a proinflammatory secretome that leads to increased bone resorption and decreased bone formation, and approaches that either eliminate senescent cells or impair the production of their proinflammatory secretome have been shown to prevent age-related bone loss in mice. Conclusions Targeting cellular senescence represents a novel therapeutic strategy to prevent not only bone loss but potentially multiple age-related diseases simultaneously.