Academic Responsibilities: 

Professor of Pediatrics, Physiology, and Medicine

Associate Chairman for Patient Oriented Research 

Director, Center for Hypotension

Email: Stewart@nymc.edu
Office Location:
Suite 1600
19 Bradhurst Avenue
New York Medical College
Hawthorne, NY 10532
 
Julian M. Stewart, M.D., Ph.D.

Academic Profile:

 
Residency/Fellowship Training Pediatrics/Pediatric Cardiology
Director Center for Hypotension
Faculty Government
CDC-NIH Committee on Chronic Fatigue in Adolescents 
NIH/NIAID Special Emphasis Panel DOD Gulf War Syndrome
CFS/Fibromyalgia
 
Ad Hoc Reviewer CVS- A
 
Reviewer CICS
Academic Committees Associate Chairman IRB
Research Profile

Our investigational clinical interests involve the regulation of heart rate and blood pressure in children and adolescents. Circulatory physiology remains ill-determined in children with a variety of problems with neurovascular dysfunction. We have established a Center for Hypotension-Related Disease aimed at young people from childhood through young adult with neurally mediated syncope, chronic orthostatic intolerance, chronic fatigue syndrome, orthostatic intolerance of other etiologies such as occur in the postural tachycardia syndrome (POTS). Research focus is on circulatory and vascular problems and their autonomic consequences including altered peripheral arterial and venous properties and changes in blood volume and its redistribution. Molecular mechanisms including cytokine and nitric oxide assessment are explored. Treatment protocols are tested. Methods include plethysmographic measurements of peripheral and central blood flow, capacitance and peripheral permeability measurements, skin blood flow measurements using laser-Doppler flowmetry, baroreflex assessment,  standard circulatory autonomic function tests, assessment of the efficacy of the skeletal muscle pump, and tests of heart rate and blood pressure variability. Orthostatic stress is used as a provocative stimulus.

Other research interests include computational circulatory physiology investigating vascular and cardiac properties in animal model systems as well as during diagnostic procedures such as cardiac catheterization and flow-volume monitoring and redistribution in critically ill infants and children. Correlative work studying the relation of cardiovascular properties to nitric oxide physiology is in progress. Recent work has also included connections of peripheral flow and muscle pump activity with osteoporosis, and contractual work with the Department of Defense related to muscular dystrophy.

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Education Profile

 
Post Graduate Studies  Medicine - Physiology/Biophysics
Post Doctoral Studies Pediatric Cardiology - Cornell/NY Hospital
Residency New York University Medical Center
Fellowship Cornell University-New York Hospital
Graduate Degree  M.D., Ph.D.
Graduate Degree Institution  University of Chicago
Undergraduate Degree A.B. Physics
Undergraduate Institution Cornell University
Professional Information:
 
  The Association for Patient Oriented Research, American Autonomic Society, NE Regional Pediatric Cardiology Society, American Heart Association, American College of Cardiology, American Pediatric Society 
Fellowships American Academy of Pediatrics, American College of Cardiology
Currently Active Grants

 1RO1-HL08803  (Stewart, PI)

4/1/08-3/31/12

Vascular Dysfunction in Chronic Fatigue Syndrome  

The goal of this project is to investigate blood flow abnormalities in young people with CFS

 1RO1-HL074873 (Stewart,PI)

7/1/10-6/30/14

 Local Vasoconstriction in Postural Tachycardia Syndrome  

The  goal is to determine how abnormalities of neurovascular regulation and oxidative stress  account for blood flow abnormalities in postural tachycardia syndrome in young people.

 1R21HL091948(Stewart PI)

12/31/03-12/30/04

 Hyperpnea in Postural Tachycardia Syndrome

The goals are to determine whether chemoreflex function abnormalities account for hyperpnea in postural tachycardia syndrome.

 1R21HL091948 (Stewart PI)

12/31/03-12/30/04

 Hyperpnea in Postural Tachycardia Syndrome

The goals are to determine whether chemoreflex function abnormalities account for hyperpnea in postural tachycardia syndrome.

 1F30HL097380 (Ocon PI, Stewart Sponsor)

7/1/09-6/30/15

Inhibition of NO Dependent Splanchnic Hyperemia Improves CFS/POTS

The goals are to determine the isoform dependence of increased cutaneous NO in CFS/POTS and determine whether protein and mRNA expression of NOS isoforms are increased and to test the hypothesis that the guanylate cyclase inhibitor methylene blue differentially decreases splanchnic pooling in CFS/POTS patients compared to healthy control subjects.

Editorial Board

Am J Physiol-Heart and Circulatory Physiology, Circulation 

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Selected Bibliography
 
 
Stewart JM, Erb M, Sorbera C. Heart rate variability and the outcome of head-up tilt in syncopal children. Peds Res 1996;5:702-709.
Julian Stewart, Amy Weldon, Nina Arlievsky, Karl Li, Jose Munoz Neurally Mediated Hypotension and Autonomic Dysfunction Measured by Heart Rate variability During Head-up tilt Testing in Children with the Chronic Fatigue Syndrome. Clin Autonom Res 1998;8:221-230.
Julian M. Stewart, Michael H Gewitz, Amy Weldon, Nina Arlievsky, Karl Li, Jose Munoz. The Nature of Neurally Mediated Hypotension in Adolescents with the Chronic Fatigue Syndrome.Pediatrics 1999;103:116-121.
Stewart JM, Weldon A, Munoz JL. Pattern of orthostatic intolerance: the orthostatic tachycardia . Jl of Pediatrics 1999; 135: 218-225.
Stewart JM. Vascular Perturbations in the Chronic Orthostatic Intolerance of the Postural Orthostatic Tachycardia Syndrome. Jl Applied Physiology, 2000;89:1505-1512.
Stewart JM. Autonomic Nervous System Dysfunction in Adolescents with Orthostatic Tachycardia Syndrome and the Chronic Fatigue Syndrome is Characterized by Attenuated Vagal Baroreflex and Potentiated Sympathetic Vasomotion Peds Res 2000;48:218-226.
Stewart, JM,  Weldon AA. Reflex vascular defects in the orthostatic tachycardia syndrome of adolescents J. Appl. Physiol. 2001 90: 2025-2031.
 Stewart JM, Lavin J, Weldon AA. Orthostasis Fails to Produce Active Limb Venoconstriction  in Adolescents.  J Appl Physiol 91: 1723–1729, 2001.
Stewart JM. Transient orthostatic hypotension is common in adolescents. J Pediatr 2002;140:418-424.
 Stewart JM Pooling in chronic Orthostatic Intolerance: Arterial Vasoconstrictive but not Venous Compliance Defects. Circulation 2002;105:2274-2281.
Stewart JM Medical Progress Orthostatic Intolerance In Pediatrics. J Pediatr 2002; 140:404-411.
Stewart JM, Kyle, K, Weldon A. Acute Effects of Phenylephrine and Esmolol Infusions on Autonomic Function in Chronic Orthostatic Intolerance. Circulation 106(23):2946-2954, 2002.
Stewart JM. Microvascular Filtration is Increased in Postural Tachycardia Syndrome Circulation 107:1-7; 2003
Stewart JM, Medow M, Montgomery LD. Local Vascular Responses Affecting Blood Flow in Postural Tachycardia American Journal of Physiology, Heart and Circulatory Physiology Am J Physiol Heart Circ Physiol 285: H2749–H2756, 2003.
Stewart, JM, Medow MS, Montgomery LD, McLeod K. Decreased Skeletal Muscle Pump Activity in Postural Tachycardia with Low Peripheral Blood Flow. Am J Physiol Heart Circ Physiol 286:H1216–H1222,2004.
Stewart, JM A Physiological Classification of the Postural Tachycardia Syndrome Based on Peripheral Blood Flow. In Articles in Press. Am J Physiol Heart Circ Physiol, 2004.

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