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Full-Text Articles in Analytical, Diagnostic and Therapeutic Techniques and Equipment

Understanding Atp-Mediated Vasodilatation In Humans, Anne R. Crecelius, Frank A. Dinenno Jan 2015

Understanding Atp-Mediated Vasodilatation In Humans, Anne R. Crecelius, Frank A. Dinenno

Anne R. Crecelius

Negative results, cynicism, the piecing together of puzzles and integrating physiology with experimental approaches are all part of the inspiring and meandering journey on the path to understand ATP-mediated vasodilatation. While it is satisfying to be "right" as scientists, we know sometimes the most important progress occurs when data are surprising or contrary to our original hypothesis. The pursuit of explanations for unexpected findings often leads to the best advancements. The story of how our laboratory came to investigate the underlying vasodilatator pathways of adenosine triphosphate (ATP) is an example of such a path to our current understanding.


Impaired Skeletal Muscle Blood Flow Control With Advancing Age In Humans: Attenuated Atp Release And Local Vasodilation During Erythrocyte Deoxygenation, Brett S. Kirby, Anne R. Crecelius, Wyatt F. Voyles, Frank A. Dinenno Jan 2015

Impaired Skeletal Muscle Blood Flow Control With Advancing Age In Humans: Attenuated Atp Release And Local Vasodilation During Erythrocyte Deoxygenation, Brett S. Kirby, Anne R. Crecelius, Wyatt F. Voyles, Frank A. Dinenno

Anne R. Crecelius

Rationale: Skeletal muscle blood flow is coupled with the oxygenation state of hemoglobin in young adults, whereby the erythrocyte functions as an oxygen sensor and releases ATP during deoxygenation to evoke vasodilation. Whether this function is impaired in humans of advanced age is unknown. Objective: To test the hypothesis that older adults demonstrate impaired muscle blood flow and lower intravascular ATP during conditions of erythrocyte deoxygenation. Methods and Results: We showed impaired forearm blood flow responses during 2 conditions of erythrocyte deoxygenation (systemic hypoxia and graded handgrip exercise) with age, which was caused by reduced local vasodilation. In young adults, …


Contributions Of Body Fat And Effort In The 5k Run: Age And Body Weight Handicap, Anne R. Crecelius, Paul M. Vanderburgh, Lloyd L. Laubach Jan 2015

Contributions Of Body Fat And Effort In The 5k Run: Age And Body Weight Handicap, Anne R. Crecelius, Paul M. Vanderburgh, Lloyd L. Laubach

Anne R. Crecelius

The 5K handicap (5KH), designed to eliminate the body weight (BW) and age biases inherent in the 5K run time (RT), yields an adjusted RT (RTadj) that can be compared between runners of different BW and age. As hypothesized in a validation study, however, not all BW bias may be removed, because of the influences of body fatness (BF) and effort (run speed; essentially the inverse as measured by rating of perceived exertion (RPE)). This study's purpose was to determine the effects of BF and RPE on BW bias in the 5KH. For 99 male runners in a regional 5K …


Muscle Contraction Duration And Fibre Recruitment Influence Blood Flow And Vo2 Independent Of Contractile Work During Steady-State Exercise In Humans, Jennifer C. Richards, Anne R. Crecelius, Brett S. Kirby, Dennis G. Larson, Frank A. Dinenno Jan 2015

Muscle Contraction Duration And Fibre Recruitment Influence Blood Flow And Vo2 Independent Of Contractile Work During Steady-State Exercise In Humans, Jennifer C. Richards, Anne R. Crecelius, Brett S. Kirby, Dennis G. Larson, Frank A. Dinenno

Anne R. Crecelius

We tested the hypothesis that, among conditions of matched contractile work, shorter contraction durations and greater muscle fibre recruitment result in augmented skeletal muscle blood flow and oxygen consumption (O2) during steady-state exercise in humans. To do so, we measured forearm blood flow (FBF; Doppler ultrasound) during 4 minutes of rhythmic handgrip exercise in 24 healthy young adults and calculated forearm O2 via blood samples obtained from a catheter placed in retrograde fashion into a deep vein draining the forearm muscle. In Protocol 1 (n = 11), subjects performed rhythmic isometric handgrip exercise at mild and moderate intensities under conditions …


Reactive Hyperemia Occurs Via Activation Of Inwardly-Rectifying Potassium Channels And Na+/K+-Atpase In Humans, Anne R. Crecelius, Jennifer C. Richards, Gary J. Luckasen, Dennis G. Larson, Frank A. Dinenno Jan 2015

Reactive Hyperemia Occurs Via Activation Of Inwardly-Rectifying Potassium Channels And Na+/K+-Atpase In Humans, Anne R. Crecelius, Jennifer C. Richards, Gary J. Luckasen, Dennis G. Larson, Frank A. Dinenno

Anne R. Crecelius

Rationale: Reactive hyperemia (RH) in the forearm circulation is an important marker of cardiovascular health, yet the underlying vasodilator signaling pathways are controversial and thus remain unclear. Objective: We hypothesized that RH occurs via activation of inwardly rectifying potassium (KIR) channels and Na+/K+-ATPase and is largely independent of the combined production of the endothelial autocoids nitric oxide (NO) and prostaglandins in young healthy humans. Methods and Results: In 24 (23±1 years) subjects, we performed RH trials by measuring forearm blood flow (FBF; venous occlusion plethysmography) after 5 minutes of arterial occlusion. In protocol 1, we studied 2 groups of 8 …