A5061454061- Respiratory Support and Mechanisms
- Neuroscience of respiration and sleep
- Chronic Obstructive Pulmonary Disease (COPD) Research
- Cardiac Imaging and Diagnostics
- Cardiovascular and exercise physiology
- Cardiac Valve Diseases and Treatments
- Cardiac pacing and defibrillation studies
- Thermoregulation and physiological responses
- Exercise and Physiological Responses
- Neonatal Respiratory Health Research
- Heart Rate Variability and Autonomic Control
- Cardiovascular Function and Risk Factors
- Muscle metabolism and nutrition
- Muscle Physiology and Disorders
- Cardiac Arrhythmias and Treatments
- Intensive Care Unit Cognitive Disorders
- Sports Performance and Training
- Atrial Fibrillation Management and Outcomes
- Adipose Tissue and Metabolism
- Cardiac, Anesthesia and Surgical Outcomes
- Aortic Disease and Treatment Approaches
- Autophagy in Disease and Therapy
- Calpain Protease Function and Regulation
- Cardiac electrophysiology and arrhythmias
- Cardiac Health and Mental Health
HealthPartners
2014-2024
Brigham Young University
2006-2024
Regions Hospital
2011-2024
University of Minnesota
2000-2024
University of Minnesota Medical Center
2010-2022
Ohio Dominican University
2014-2019
University of Florida
2009-2015
Emory University
2014
National Institutes of Health
2011-2013
Deutsche Forschungsgemeinschaft
2013
Harms, Craig A., Mark A. Babcock, Steven R. McClaran, David F. Pegelow, Glenn Nickele, William B. Nelson, and Jerome Dempsey.Respiratory muscle work compromises leg blood flow during maximal exercise. J. Appl. Physiol.82(5): 1573–1583, 1997.—We hypothesized that exercise at O 2 consumption (V˙o max ), high demand for respiratory (Q˙) would elicit locomotor vasoconstriction compromise limb Q˙. Seven male cyclists 64 ± 6 ml ⋅ kg −1 min ) each completed 14 bouts of 2.5-min duration atV˙o on a...
We have recently demonstrated that changes in the work of breathing during maximal exercise affect leg blood flow and vascular conductance (C. A. Harms, M. Babcock, S. R. McClaran, D. F. Pegelow, G. Nickele, W. B. Nelson, J. Dempsey. Appl. Physiol. 82: 1573–1583, 1997). Our present study examined effects on cardiac output (CO) exercise. Eight male cyclists [maximal O 2 consumption (V˙o max ): 62 ± 5 ml ⋅ kg −1 min ] performed repeated 2.5-min bouts cycle atV˙o . Inspiratory muscle was either...
Mechanical ventilation is a life-saving intervention used to provide adequate pulmonary in patients suffering from respiratory failure. However, prolonged mechanical associated with significant diaphragmatic weakness resulting both myofiber atrophy and contractile dysfunction. Although several signaling pathways contribute diaphragm during ventilation, it established that oxidative stress required for occur. Therefore, identifying the site(s) of ventilation- induced reactive oxygen species...
We questioned whether exercise‐induced arterial hypoxaemia (EIAH) occurs in healthy active women, who have smaller lungs, reduced lung diffusion, and lower maximal O 2 consumption rate (V̇ O2,max ) than age‐ height‐matched men. Twenty‐nine young women with widely varying fitness levels ( V̇ , 57 ± 6 ml kg −1 min ; range, 35‐70 or 148 5 %; 93‐188 % predicted) normal resting function underwent an incremental treadmill test to V during the follicular phase of their menstrual cycle. Arterial...
Previous workers have demonstrated that controlled mechanical ventilation results in diaphragm inactivity and elicits a rapid development of weakness as result both contractile dysfunction fiber atrophy. Limited data exist regarding the impact pressure support ventilation, commonly used mode ventilation-that permits partial activity diaphragm-on structure function. We carried out present study to test hypothesis high-level decreases pathology associated with CMV.Sprague-Dawley rats were...
Prolonged mechanical ventilation (MV) results in diaphragmatic weakness due to fiber atrophy and contractile dysfunction. Recent work reveals that activation of the proteases calpain caspase-3 is required for MV-induced However, mechanism(s) responsible these remains unknown. To address this issue, we tested hypothesis oxidative stress essential diaphragm during MV. Cause-and-effect was established by prevention using antioxidant Trolox. Treatment animals with Trolox prevented protein...
This study determined the contribution of extracellular matrix (ECM) remodeling to protective adaptation human skeletal muscle known as repeated-bout effect (RBE). Muscle biopsies were obtained 3 hours, 2 days, and 27 days following an initial bout (B1) lengthening contractions (LCs) a repeated (B2) in separate studies. Biopsies from nonexercised legs served controls. In first study, global transcriptomic analysis indicated widespread changes ECM structural, deadhesive, signaling...
Respiratory muscle weakness resulting from both diaphragmatic contractile dysfunction and atrophy has been hypothesized to contribute the weaning difficulties associated with prolonged mechanical ventilation (MV). While it is clear that oxidative injury contributes MV-induced weakness, source(s) of oxidants in diaphragm during MV remain unknown. These experiments tested hypothesis xanthine oxidase (XO) oxidant production rat oxypurinol, a XO inhibitor, would attenuate stress, dysfunction,...
Diaphragmatic weakness, due to both atrophy and contractile dysfunction, is a well-documented response following prolonged mechanical ventilation. Evidence indicates that activation of the proteases calpain caspase-3 essential for ventilation-induced diaphragmatic weakness occur. We tested hypothesis regulatory cross-talk exists between in diaphragm during To test this prediction, we determined whether selective pharmacological inhibition would prevent conversely abate activation.Animal...
Skeletal muscle responds to exercise-induced damage by orchestrating an adaptive process that protects the from subsequent bouts of exercise, a phenomenon called repeated bout effect (RBE). The mechanisms underlying RBE are not understood. We hypothesized attenuated inflammation response following lengthening contractions (LC) would be coincidental with RBE, suggesting potential relationship. Fourteen men (n = 7) and women completed two separated 28 days. Muscle biopsies were taken before...
The work of breathing (W b ) normally incurred during maximal exercise not only requires substantial cardiac output and O 2 consumption (V˙o but also causes vasoconstriction in locomotor muscles compromises leg blood flow (Q˙ ). We wondered whether the W submaximal would reduceQ˙ . Therefore, we investigated effects changing onQ˙ via thermodilution 10 healthy trained male cyclists [maximalV˙o max = 59 ± 9 ml ⋅ kg −1 min ] repeated bouts cycle at rates corresponding to 50 75% ofV˙o...
HARMS, C, A., S. R. McCLARAN, G. A. NICKELE, D. F. PEGELOW, W. B. NELSON, and J. DEMPSEY. Effect of exercise-induced arterial O2 desaturation on V̇O2max in women. Med. Sci. Sports Exerc., Vol. 32, No. 6, pp. 1101–1108, 2000. Purpose We have recently reported that many healthy habitually active women experience exercise induced hypoxemia (EIAH). questioned whether EIAH affected this population the effect was similar to men. Methods Twenty-five young with widely varying fitness levels...
Controlled mechanical ventilation (MV) is a life-saving measure for patients in respiratory failure. However, MV renders the diaphragm inactive leading to weakness due both atrophy and contractile dysfunction. It now established that oxidative stress requirement MV-induced diaphragmatic proteolysis, atrophy, dysfunction occur. Given endurance exercise can elevate antioxidant capacity levels of cellular protein heat shock 72 (HSP72), we hypothesized training before would protect against...
Objectives: Although mechanical ventilation is a life-saving measure for patients in respiratory failure, prolonged results diaphragmatic weakness attributable to fiber atrophy and contractile dysfunction. Therefore, identifying the signaling pathways responsible ventilation-induced important. In this context, it established that oxidative stress required occur. Numerous redox-sensitive exist muscle including transcription factor nuclear factor-κB. has been suggested factor-κB contributes...
Mechanical ventilation (MV) is a life-saving intervention in patients respiratory failure. Unfortunately, prolonged MV results the rapid development of diaphragm atrophy and weakness. MV-induced diaphragmatic weakness significant because inspiratory muscle dysfunction risk factor for problematic weaning from MV. Therefore, developing clinical to prevent important. In this regard, occurs due both increased proteolysis decreased protein synthesis. While efforts impede are well-documented, only...
Twenty-eight healthy women (ages 27.2 ± 6.4 yr) with widely varying fitness levels [maximal O 2 consumption (V˙o max ), 31–70 ml ⋅ kg −1 min ] first completed a progressive incremental treadmill test toV˙o (total duration, 13.3 1.4 min; 97 37 s at maximal workload), rested for 20 min, and then constant-load workload 143 31 s). At the termination of test, 6 subjects had maintained arterial [Formula: see text] text]) near resting levels, whereas 22 showed >10 Torr decrease in[Formula: [78.0...
Left ventricular dysfunction is common after coronary artery bypass graft and valve replacement surgeries often treated with inotropic drugs to maintain adequate hemodynamic status. In this study, we aimed identify the demographic, clinical, laboratory, echocardiographic factors that are associated use of in patients undergoing concomitant aortic surgery.The study included 97 who had undergone at Regions Hospital, University Minnesota Medical School from January 2006 December 2008. All data...
Objectives: Mechanical ventilation is a lifesaving measure for patients with respiratory failure. However, prolonged mechanical results in diaphragm weakness, which contributes to problems weaning from the ventilator. Therefore, identifying signaling pathways responsible ventilation–induced weakness essential developing effective countermeasures combat this important problem. In regard, forkhead boxO family of transcription factors activated during ventilation, and boxO–specific can lead...