Anatomy Commons^™

Can Time-Resolved Nirs Provide The Sensitivity To Detect Brain Activity During Motor Imagery Consistently?, Androu Abdalmalak, Daniel Milej, Mamadou Diop, Mahsa Shokouhi, Lorina Naci, Adrian M. Owen, Keith St. Lawrence

Anatomy and Cell Biology Publications

Previous functional magnetic resonance imaging (fMRI) studies have shown that a subgroup of patients diagnosed as being in a vegetative state are aware and able to communicate by performing a motor imagery task in response to commands. Due to the fMRI's cost and accessibility, there is a need for exploring different imaging modalities that can be used at the bedside. A promising technique is functional near infrared spectroscopy (fNIRS) that has been successfully applied to measure brain oxygenation in humans. Due to the limited depth sensitivity of continuous-wave NIRS, time-resolved (TR) detection has been proposed as a way of enhancing …

Anatomical Knowledge Retention In Changing Curricula, Alexa Lean, Juliet Lee, Ellen Goldman, Gisela Butera, Kirsten Brown, Rosalyn Jurjus

GW Research Days 2016 - 2020

Traditionally anatomy is one of the first subjects taught in medical school. Practicing physicians have commented on medical students’ poor anatomical knowledge in surgically oriented clerkships. Literature also shows that correlating clinical and anatomical sciences throughout early medical education may improve anatomical knowledge retention. With major medical school curricular changes happening across the nation, more quantitative data confirming this correlation is needed.

The medical curriculum at the George Washington University School of Medicine recently underwent reorganization, transforming an earlier discipline-based curriculum to that of an integrated system-based one. In order to determine whether reorganization has an effect on anatomical knowledge …

The Effect Of Barefoot Running Using Two Running Styles On Lower Extremity Joint Reaction Forces, Jamie M. Rogers

Senior Honors Theses

Running is a popular worldwide activity with many varying biomechanical techniques. Investigating potential differences in joint forces can be beneficial in determining if there is a superior biomechanical running pattern. Previous research compared barefoot and shod running, as well as the kinetic effects of varied running styles. The current study investigated the differences in internal joint reaction forces (JRF) at the hip, knee, and ankle joints during running with two different styles. Ten male and ten female participants who naturally run with a rearfoot strike pattern were included in this study. Each subject ran barefoot on an instrumented treadmill for …

Aging And Muscle Fatigability In The Upper Extremity, Andrew Kuplic

Master's Theses (2009 -)

Aging is accompanied by reductions in strength and contraction velocity, and increased fatigability of limb muscles during high-velocity dynamic contractions. These age-related changes affect functional tasks and are well described for the lower limb, with less known about the upper limb muscles. The aims of the thesis were to compare in young and old men and women: (1) maximal torque and power of the elbow flexor muscles across a range of isokinetic velocities, and (2) the neural (supraspinal) and muscular mechanisms of fatigue induced by high-velocity dynamic contractions of the elbow flexor muscles. 28 young (23.2 ± 2.6 years) men …

A Rare Case Of Vascular Ring And Coarctation Of The Aorta In Association With Charge Syndrome., Jonathan B. Wagner, Joshua Q. Knowlton, Peter Pastuszko, Sanket Shah

Manuscripts, Articles, Book Chapters and Other Papers

A male neonate presented with CHARGE syndrome, a multiorgan genetic disorder involving the Coloboma of the eyes, congenital Heart defects, nasal choanal Atresia, growth and development Retardation, Genitourinary disorders, and Ear anomalies and deafness. Moreover, he had a rare case of vascular ring-consisting of a right aortic arch with retroesophageal brachiocephalic artery-combined with coarctation of the mid-aortic arch. He underwent both vascular ring and aortic arch repair at our institution. To our knowledge, this is the 4th documented case of this exceedingly rare type of aortic arch anomaly combined with aortic arch obstruction. Moreover, it is the first confirmed case …

Genomic Contraindications For Heart Transplantation., Danton S. Char, Gabriel Lázaro-Muñoz, Aliessa Barnes, David Magnus, Michael J. Deem, John Lantos

Manuscripts, Articles, Book Chapters and Other Papers

Genome sequencing raises new ethical challenges. Decoding the genome produces new forms of diagnostic and prognostic information; however, the information is often difficult to interpret. The connection between most genetic variants and their phenotypic manifestations is not understood. This scenario is particularly true for disorders that are not associated with an autosomal genetic variant. The analytic uncertainty is compounded by moral uncertainty about how, exactly, the results of genomic testing should influence clinical decisions. In this Ethics Rounds, we present a case in which genomic findings seemed to play a role in deciding whether a patient was to be listed …

Cigarette Smoke Impairs A2a Adenosine Receptor Mediated Wound Repair Through Up-Regulation Of Duox-1 Expression., Zhi Tian, Hui Zhang, Jendayi Dixon, Nicole Traphagen, Todd A. Wyatt, Kusum K. Kharbanda, Samantha Simet, Narasaiah Kolliputi, Diane S Allen-Gipson

Journal Articles: Pulmonary & Critical Care Med

Cigarette smoke (CS) exposure and intrinsic factors such as the NADPH oxidases produce high levels of reactive oxygen species (ROS), ensuing inflammatory tissue injury. We previously demonstrated that CS-generated ROS, particularly hydrogen peroxide (H2O2), impaired adenosine stimulated wound repair. We hypothesized that CS exposure modulates expression of Dual oxidase 1 (Duox-1), a NADPH oxidases known to generate H2O2. To test this hypothesis, we used human bronchial epithelial cell line Nuli-1 and C57BL/6 mice. Cells were treated with 5% CS extract (CSE) for various periods of time, and mice were exposed to whole body CS for six weeks. Both CSE and …

Effect Of Low-Level Co2 On Innate Inflammatory Protein Response To Organic Dust From Swine Confinement Barns., David Schneberger, Jane M. Devasure, Kristina L. Bailey, Debra J. Romberger, Todd A. Wyatt

Journal Articles: Pulmonary & Critical Care Med

BACKGROUND: Organic hog barn dust (HDE) exposure induces lung inflammation and long-term decreases in lung function in agricultural workers. While concentrations of common gasses in confined animal facilities are well characterized, few studies have been done addressing if exposure to elevated barn gasses impacts the lung immune response to organic dusts. Given the well documented effects of hypercapnia at much higher levels we hypothesized that CO2 at 8 h exposure limit levels (5000 ppm) could alter innate immune responses to HDE.

METHODS: Using a mouse model, C57BL/6 mice were nasally instilled with defined barn dust extracts and then housed in …

Effect Of Low-Level Co2 On Innate Inflammatory Protein Response To Organic Dust From Swine Confinement Barns., David Schneberger, Jane M. Devasure, Kristina L. Bailey, Debra J. Romberger, Todd A. Wyatt

Journal Articles: Pulmonary & Critical Care Med

BACKGROUND: Organic hog barn dust (HDE) exposure induces lung inflammation and long-term decreases in lung function in agricultural workers. While concentrations of common gasses in confined animal facilities are well characterized, few studies have been done addressing if exposure to elevated barn gasses impacts the lung immune response to organic dusts. Given the well documented effects of hypercapnia at much higher levels we hypothesized that CO2 at 8 h exposure limit levels (5000 ppm) could alter innate immune responses to HDE.

METHODS: Using a mouse model, C57BL/6 mice were nasally instilled with defined barn dust extracts and then housed in …

Ang1 Treatment Reduces Muscle Pathology And Prevents A Decline In Perfusion In Dmd Mice, Kelly M. Gutpell, Nikola Tasevski, Boaz Wong, William Thomas Hrinivich, Feng Su, Lise Desjardins, Ting-Yim Lee, Lisa Marie Hoffman

Anatomy and Cell Biology Publications

Vascular endothelial growth factor (VEGF) and other pro-angiogenic growth factors have been investigated to enhance muscle tissue perfusion and repair in Duchenne muscular dystrophy (DMD). Current understanding is limited by a lack of functional data following in vivo delivery of these growth factors. We previously used dynamic contrast-enhanced computed tomography to monitor disease progression in murine models of DMD, but no study to date has utilized this imaging technique to assess vascular therapy in a preclinical model of DMD. In the current study, we locally delivered VEGF and ANG1 alone or in combination to dystrophic hind limb skeletal muscle. Using …

Cost-Effectiveness Of Cerebrospinal Biomarkers For The Diagnosis Of Alzheimer's Disease, Spencer A. W. Lee, Luciano A. Sposato, Vladimir Hachinski, Lauren E. Cipriano

Anatomy and Cell Biology Publications

Background: Accurate and timely diagnosis of Alzheimer's disease (AD) is important for prompt initiation of treatment in patients with AD and to avoid inappropriate treatment of patients with false-positive diagnoses. Methods: Using a Markov model, we estimated the lifetime costs and quality-adjusted life-years (QALYs) of cerebrospinal fluid biomarker analysis in a cohort of patients referred to a neurologist or memory clinic with suspected AD who remained without a definitive diagnosis of AD or another condition after neuroimaging. Parametric values were estimated from previous health economic models and the medical literature. Extensive deterministic and probabilistic sensitivity analyses were performed to evaluate …

The Effects Of Intrauterine Growth Restriction (Iugr) On The Pulmonary Surfactant And Lung Injury, Reza Khazaee

Western Research Forum

The Effects of Intrauterine Growth Restriction (IUGR) on the Pulmonary Surfactant and Lung Injury

Khazaee R¹, McCaig LA², Hardy D¹, Yamashita CM², Veldhuizen, RAW²

Department of Physiology and Pharmacology¹, Western University, London, ON, Canada. Lawson Health Research Institute², London, ON, Canada

Background: Acute respiratory distress syndrome (ARDS) is defined as severe lung dysfunction that occurs after an insult to the lung such as an infection. The lung dysfunction in ARDS is due to alterations to surfactant, a lipid-protein mixture coats the inside of the lung and …

Mortality Associated With Gastrointestinal Bleeding In Children: A Retrospective Cohort Study., Thomas M. Attard, Mikaela Miller, Chaitanya Pant, Ashwath Kumar, Mike Thomson

Manuscripts, Articles, Book Chapters and Other Papers

AIM: To determine the clinical characteristics of children with gastrointestinal bleeding (GIB) who died during the course of their admission.

METHODS: We interrogated the Pediatric Hospital Information System database, including International Classification of Diseases, Current Procedural Terminology and Clinical Transaction Classification coding from 47 pediatric tertiary centers extracting the population of patients (1-21 years of age) admitted (inpatient or observation) with acute, upper or indeterminate GIB (1/2007-9/2015). Descriptive statistics, unadjusted univariate and adjusted multivariate analysis of the associations between patient characteristics and treatment course with mortality was performed with mortality as primary and endoscopy a secondary outcome of interest. All …

The Effect Of Object-Centered Instructions In Cartesian And Polar Coordinates On Saccade Vector, Jay A. Edelman, Alexa M. Mieses, Kira Konnova, David Shiu

Publications and Research

Express saccades (ES) are the most reflexive saccadic eye movements, with very short reaction times of 70– 110 ms. It is likely that ES have the shortest saccade reaction times (SRTs) possible given the known physiological and anatomical delays present in sensory and motor systems. Nevertheless, it has been demonstrated that a vector displacement of ES to spatially extended stimuli can be influenced by spatial cognition. Edelman, Kristjansson, and Nakayama (2007) found that when two horizontally separated visual stimuli appear at a random location, the spatial vector, but not the reaction time, of human ES is strongly influenced by an …

What Is The Contribution Of Ia-Afference For Regulating Motor Output Variability During Standing?, Niklas König Ignasiak

Physical Therapy Faculty Articles and Research

Motor variability is an inherent feature of all human movements, and describes the system‘s stability and rigidity during the performance of functional motor tasks such as balancing. In order to ensure successful task execution, the nervous system is thought to be able to flexibly select the appropriate level of variability. However, it remains unknown which neurophysiological pathways are utilized for the control of motor output variability. In responding to natural variability (in this example sway), it is plausible that the neuro-physiological response to muscular elongation contributes to restoring a balanced upright posture. In this study, the postural sway of 18 …

Micrornas, Heart Failure, And Aging: Potential Interactions With Skeletal Muscle, Kevin A. Murach, John J. Mccarthy

Center for Muscle Biology Faculty Publications

MicroRNAs (miRNAs) are small noncoding RNAs that regulate gene expression by targeting mRNAs for degradation or translational repression. MiRNAs can be expressed tissue specifically and are altered in response to various physiological conditions. It has recently been shown that miRNAs are released into the circulation, potentially for the purpose of communicating with distant tissues. This manuscript discusses miRNA alterations in cardiac muscle and the circulation during heart failure, a prevalent and costly public health issue. A potential mechanism for how skeletal muscle maladaptations during heart failure could be mediated by myocardium-derived miRNAs released to the circulation is presented. An overview …

A Method For Independent Component Graph Analysis Of Resting-State Fmri, Demetrius Ribeiro De Paula, Erik Ziegler, Pubuditha M. Abeyasinghe, Tushar K. Das

Anatomy and Cell Biology Publications

Introduction: Independent component analysis (ICA) has been extensively used for reducing task-free BOLD fMRI recordings into spatial maps and their associated time-courses. The spatially identified independent components can be considered as intrinsic connectivity networks (ICNs) of non-contiguous regions. To date, the spatial patterns of the networks have been analyzed with techniques developed for volumetric data. Objective: Here, we detail a graph building technique that allows these ICNs to be analyzed with graph theory. Methods: First, ICA was performed at the single-subject level in 15 healthy volunteers using a 3T MRI scanner. The identification of nine networks was performed by a …

Eligibility For Minimally Invasive Coronary Artery Bypass Examination Of Epicardial Adipose Tissue Using Computed Tomography, Kate E. M. Dillon, Marjorie Johnson, Bob Kiaii

Anatomy and Cell Biology Publications

Objective: A variable that necessitates conversion to a conventional full-sternotomy coronary artery bypass procedure from a robotic-assisted endoscopic single-vessel small thoracotomy is the inability to visualize the left anterior descending coronary artery within the surrounding epicardial adipose tissue using the endoscopic camera. The purpose of this study was to determine whether anatomical properties of the epicardial adipose tissue examined using preoperative computed tomography (CT) images are able to predict and thus reduce the need for intraoperative conversion based on effective preoperative exclusion criteria. Methods: Retrospective analysis of patient preoperative CT angiography scans from both converted (n = 17) and successful …

Using A Respiratory Navigator Significantly Reduces Variability When Quantifying Left Ventricular Torsion With Cardiovascular Magnetic Resonance, Sean M. Hamlet, Christopher M. Haggerty, Jonathan D. Suever, Gregory J. Wehner, Kristin N. Andres, David K. Powell, Richard J. Charnigo, Brandon K. Fornwalt

Electrical and Computer Engineering Faculty Publications

Background: Left ventricular (LV) torsion is an important indicator of cardiac function that is limited by high inter-test variability (50% of the mean value). We hypothesized that this high inter-test variability is partly due to inconsistent breath-hold positions during serial image acquisitions, which could be significantly improved by using a respiratory navigator for cardiovascular magnetic resonance (CMR) based quantification of LV torsion.

Methods: We assessed respiratory-related variability in measured LV torsion with two distinct experimental protocols. First, 17 volunteers were recruited for CMR with cine displacement encoding with stimulated echoes (DENSE) in which a respiratory navigator was used to measure …

Reduced Skeletal Muscle Satellite Cell Number Alters Muscle Morphology After Chronic Stretch But Allows Limited Serial Sarcomere Addition, Matthew C. Kinney, Sudarshan Dayanidhi, Peter B. Dykstra, John J. Mccarthy, Charlotte A. Peterson, Richard L. Lieber

Physiology Faculty Publications

Introduction: Muscles add sarcomeres in response to stretch, presumably to maintain optimal sarcomere length. Clinical evidence from patients with cerebral palsy, who have both decreased serial sarcomere number and reduced satellite cells (SCs), suggests a hypothesis that SCs may be involved in sarcomere addition. Methods: A transgenic Pax7‐DTA mouse model underwent conditional SC depletion, and their soleii were then stretch‐immobilized to assess the capacity for sarcomere addition. Muscle architecture, morphology, and extracellular matrix (ECM) changes were also evaluated. Results: Mice in the SC‐reduced group achieved normal serial sarcomere addition in response to stretch. However, muscle fiber cross‐sectional …

Longitudinal Cardiovascular Outcomes Of Sleep Disordered Breathing In Children: A Meta-Analysis And Systematic Review., Zarmina Ehsan, Stacey L. Ishman, Thomas R. Kimball, Nanhua Zhang, Yuanshu Zou, Raouf S. Amin

Manuscripts, Articles, Book Chapters and Other Papers

Objectives: The presence of sleep disordered breathing (SDB) is known to impact long-term cardiovascular morbidity in adults; however, the long-term effects in children are poorly understood. We aimed to systematically review and synthesize studies published to date on the long-term effects of SDB in children.

Study Design: Meta-analysis and systematic review using PubMed, CINAHL, Embase, and Scopus (all indexed years).

Methods: We searched for English-language articles containing original human data from prospective studies, with ≥7 participants, in children ≤18 years of age. Data regarding study design, demographics, clinical characteristics, outcomes, level of evidence, and risk of bias were obtained. Articles …

Embryonic Transcription Factor Expression In Mice Predicts Medial Amygdala Neuronal Identity And Sex-Specific Responses To Innate Behavioral Cues., Julieta E Lischinsky, Katie Sokolowski, Li Peijun, Shigeyuki Esumi, Yasmin Kamal, Meredith Goodrich, Livio Oboti, Timothy R Hammond, Meera Krishnamoorthy, Daniel Feldman, Molly Huntsman, Judy Liu, Joshua G Corbin

Pediatrics Faculty Publications

The medial subnucleus of the amygdala (MeA) plays a central role in processing sensory cues required for innate behaviors. However, whether there is a link between developmental programs and the emergence of inborn behaviors remains unknown. Our previous studies revealed that the telencephalic preoptic area (POA) embryonic niche is a novel source of MeA destined progenitors. Here, we show that the POA is comprised of distinct progenitor pools complementarily marked by the transcription factors Dbx1 and Foxp2. As determined by molecular and electrophysiological criteria this embryonic parcellation predicts postnatal MeA inhibitory neuronal subtype identity. We further find that Dbx1-derived and …

Evaluation Of [14c] And [13c]Sucrose As Blood-Brain Barrier Permeability Markers, Mohammad K. Miah, Ekram A. Chowdhury, Ulrich Bickel, Reza Mehvar

Pharmacy Faculty Articles and Research

Non-specific quantitation of [¹⁴C]sucrose in blood and brain has been routinely used as a quantitative measure of the in vivo blood-brain barrier (BBB) integrity. However, the reported apparent brain uptake clearance (K_in) of the marker varies widely (∼100 fold). We investigated the accuracy of the use of the marker in comparison with a stable isotope of sucrose ([¹³C]sucrose) measured by a specific LC-MS/MS method. Rats received single doses of each marker, and the K_in values were determined. Surprisingly, the K_in value of [¹³C]sucrose was 6-7 fold lower than that …

Gait Changes In A Line Of Mice Artificially Selected For Longer Limbs, Leah M. Sparrow, Emily Pellattt, Sabrina S. Yu, David A. Raichlen, Herman Pontzer, Campbell Rolian

Publications and Research

In legged terrestrial locomotion, the duration of stance phase, i.e., when limbs are in contact with the substrate, is positively correlated with limb length, and negatively correlated with the metabolic cost of transport. These relationships are well documented at the interspecific level, across a broad range of body sizes and travel speeds. However, such relationships are harder to evaluate within species (i.e., where natural selection operates), largely for practical reasons, including low population variance in limb length, and the presence of confounding factors such as body mass, or training. Here, we compared spatiotemporal kinematics of gait in Longshanks, a long-legged …

Osteoblast-Derived Fgf9 Regulates Skeletal Homeostasis, Liping Wang, Theresa M. Roth, Marcia J. Abbott, Linh Ho, Lalita Wattanachanya, Robert A. Nissenson

Health Sciences and Kinesiology Faculty Articles

FGF9 has complex and important roles in skeletal development and repair. We have previously observed that Fgf9 expression in osteoblasts (OBs) is regulated by G protein signaling and therefore the present study was done to determine whether OB-derived FGF9 was important in skeletal homeostasis. To directly test this idea, we deleted functional expression of Fgf9 gene in OBs using a 2.3 kb collagen type I promoter-driven Cre transgenic mouse line (Fgf9^{OB −/−}). Both Fgf9 knockout (Fgf9^{OB −/−}) and the Fgf9 floxed littermates (Fgf9^fl/fl) mice were fully backcrossed and maintained in an FBV/N background. Three …

Heart Pump Modelling: Design Of Pulsatile Flow Phantoms, Olivia Coiado, Kevin Jones, Parker Schibel, Nicolas De Almeida

Biomedical Engineering Western Regional Conference

The purpose of this project is to build a model, which mimics physiological conditions of the human cardiovascular system in order to simulate the parameters of the human heart in vivo. For this project, it was developed a flow phantom with vessel mimicking material, as well as blood-mimicking and tissue-mimicking fluid. Phantoms in general are specifically designed objects involving dedicated biomaterials to simulate special realistic circuits of human beings. To develop the flow phantom, low-priced biomaterials for blood mimicking fluid, tissue mimicking, and vessel mimicking material was researched.

Keywords: Cardiovascular system, heart pump, modelling, pulsatile.

Mitochondria Mediate Cell Membrane Repair And Contribute To Duchenne Muscular Dystrophy., Maria C Vila, Sree Rayavarapu, Marshall W Hogarth, Jack H Van Der Meulen, Adam Horn, Aurelia Defour, Shin'ichi Takeda, Kristy J. Brown, Yetrib Hathout, Kanneboyina Nagaraju, Jyoti K. Jaiswal

Genomics and Precision Medicine Faculty Publications

Dystrophin deficiency is the genetic basis for Duchenne muscular dystrophy (DMD), but the cellular basis of progressive myofiber death in DMD is not fully understood. Using two dystrophin-deficient mdx mouse models, we find that the mitochondrial dysfunction is among the earliest cellular deficits of mdx muscles. Mitochondria in dystrophic myofibers also respond poorly to sarcolemmal injury. These mitochondrial deficits reduce the ability of dystrophic muscle cell membranes to repair and are associated with a compensatory increase in dysferlin-mediated membrane repair proteins. Dysferlin deficit in mdx mice further compromises myofiber cell membrane repair and enhances the muscle pathology at an asymptomatic …

Mechanism For Generation Of Left Isomerism In Ccdc40 Mutant Embryos, Kelsey Sugrue, Irene E. Zohn

Pediatrics Faculty Publications

Leftward fluid flow in the mouse node is generated by cilia and is critical for initiating asymmetry of the left-right axis. Coiled-coil domain containing-40 (Ccdc40) plays an evolutionarily conserved role in the assembly of motile cilia and establishment of the left-right axis. Approximately one-third of Ccdc40lnks mutant embryos display situs defects and here we investigate the underlying mechanism. Ccdc40lnks mutants show delayed induction of markers of the left-lateral plate mesoderm (L-LPM) including Lefty1, Lefty2 and Nodal. Consistent with defective cilia motility compromising fluid flow across the node, initiation of asymmetric perinodal Cerberus like-2 ( …

The Need For Standardized Assessment Of Muscle Quality In Skeletal Muscle Function Deficit And Other Aging-Related Muscle Dysfunctions: A Symposium Report, Rosaly Correa De Araujo, Michael O. Harris-Love, Iva Miljkovic, Maren Fragala, Brian Anthony, Todd Manini

Exercise and Nutrition Sciences Faculty Publications

A growing body of scientific literature suggests that not only changes in skeletal muscle mass, but also other factors underpinning muscle quality, play a role in the decline in skeletal muscle function and impaired mobility associated with aging. A symposium on muscle quality and the need for standardized assessment was held on April 28, 2016 at the International Conference on Frailty and Sarcopenia Research in Philadelphia, Pennsylvania. The purpose of this symposium was to provide a venue for basic science and clinical researchers and expert clinicians to discuss muscle quality in the context of skeletal muscle function deficit and other …

Impaired Peripheral Vasodilation During Graded Systemic Hypoxia In Healthy Older Adults: Role Of The Sympathoadrenal System, Jennifer C. Richards, Anne R. Crecelius, Dennis G. Larson, Gary J. Luckasen, Frank A. Dinenno

Health and Sport Science Faculty Publications

Systemic hypoxia is a physiological and pathophysiological stress that activates the sympathoadrenal system and, in young adults, leads to peripheral vasodilation. We tested the hypothesis that peripheral vasodilation to graded systemic hypoxia is impaired in older healthy adults and that this age-associated impairment is due to attenuated β-adrenergic mediated vasodilation and elevated α-adrenergic vasoconstriction. Forearm blood flow was measured (Doppler ultrasound) and vascular conductance (FVC) was calculated in 12 young (24±1 yrs) and 10 older (63±2 yrs) adults to determine the local dilatory responses to graded hypoxia (90, 85, and 80% O2 saturations) in control conditions, following local intra-arterial blockade …