Return On Your Investment: Marvin Medow, PhD

Marvin-Medow2-300x298Principal Investigator: Marvin Medow, PhD

Institution: New York Medical College

Collaborators: Julian Stewart, MD: New York Medical College
Benjamin Natelson, MD: Beth Israel Medical Center

Project Title: Splanchnic vasoconstriction is impaired by microbiomic nitric oxide production reducing cerebral blood flow in CFS

Objective: To determine if upright posture causes neurocognitive deficits as a result of impaired cerebral blood flow and modulation of nitric oxide and reactive oxygen species.

Preliminary Outcomes:

Funding: Application to NIH pending review.

Publications (selected):

  • Clinical-ScienceDecreased upright cerebral blood flow and cerebral autoregulation in normocapnic postural tachycardia syndrome. AJP Heart and Circulatory Physiology. 2009. Link:
  • Respiration drives phase synchronization between blood pressure and RR interval following loss of cardiovagal baroreflex during vasovagal syncope. AJP Heart and Circulatory Physiology. Nov. 12, 2010. Link:
  • Reactive oxygen species from NADPH and xanthine oxidase modulate the cutaneous local heating response in healthy humans. Journal of Applied Physiology. March 24, 2011.  Link:
  • Cutaneous constitutive nitric oxide synthase activation in POTS with splanchnic hyperemia. AJP Heart and Circulatory Physiology. June 3, 2011. Link:
  • Increasing orthostatic stress impairs neurocognitive functioning in CFS and POTS and is not related to cerebral blood flow velocity. Clinical Science. E-pub ahead of print on Sept. 15, 2011. Link: (See summary below.)
  • Additional data being analyzed; manuscripts in preparation.


Upright tilt impaired cognitive function of subjects with CFS, but not healthy controls

Summary of Clinical Science publication:

Orthostatic Stress Impairs Cognition: 16 subjects who met criteria for CFS and postural orthostatic tachycardia syndrome (POTS) were compared to 20 healthy volunteers. Subjects performed cognitive testing while lying flat, then while tilted to 15, 30,45,60 and 70 degrees for 10 minutes at each angle. The test was stopped if the subject became hypotensive or requested to stop. The two groups had similar drop-out rates. At baseline, the subjects had increased heart rate and respiratory rates, but comparable intelligence and cognitive performance. However, during the tilt, compared to controls the CFS-POTS subjects cognitive performance worsened as orthostatic stress increased. The subjects had decreased accuracy and longer normalized reaction time during difficult tasks imposed on orthostatic stress.

What has the Association’s support meant to your research?

Dr. Medow: “In addition to the obvious benefits of receiving financial support from the CFIDS Association that helps to defray the cost of conducting research on CFS, my research has allowed me to interact with many CFS subjects during these studies, which has put a ‘personal face’ on this syndrome. This has increased my appreciation for the need to provide answers to the many unanswered questions about the cause of and the mechanisms that underlie symptoms of CFS. I have also enjoyed providing information about CFS through our scientific publications, and the webinars and scientific meetings arranged by the Association. Lastly, the interactions that I have had with other health care professionals I have met through the Association have provided useful insights into CFS beyond the scope of my own investigations.”