Photo of Josephine (Josephine) Mun-Yee Lok, MD

Lok, Josephine Mun-Yee, MD

  • Physician, Assistant in Pediatrics, Pediatric Critical Care Medicine






Centers & Specialties

MassGeneral Hospital for Children

Medical Education
  • MD, Albert Einstein College of Medicine
  • Residency, Beth Israel Deaconess Medical Center|Residency, Tufts Medical Center
  • Fellowship, The Johns Hopkins Hospital
Board Certifications
  • Pediatric Critical Care Medicine
Foreign Languages
  • Cantonese/Yue
  • Boston: Massachusetts General Hospital
Insurances Accepted
  • Aetna Health Inc.
  • Beech Street
  • Blue Cross Blue Shield - Blue Care 65
  • Blue Cross Blue Shield - Indemnity
  • Blue Cross Blue Shield - Managed Care
  • Blue Cross Blue Shield - Partners Plus
  • Cigna (PAL #'s)
  • Fallon Community HealthCare
  • Great-West Healthcare (formally One Health Plan)
  • Harvard Pilgrim Health Plan - ACD
  • Harvard Pilgrim Health Plan - PBO
  • Health Care Value Management (HCVM)
  • Humana/Choice Care PPO
  • MassHealth
  • Medicare
  • Medicare - ACD
  • Neighborhood Health Plan - ACD
  • Neighborhood Health Plan - PBO
  • OSW - Connecticut
  • OSW - Maine
  • OSW - New Hampshire
  • OSW - New York
  • OSW - Rhode Island
  • OSW - Vermont
  • Private Health Care Systems (PHCS)
  • Senior Whole Health
  • TriCare
  • Tufts Health Plan
  • Unicare
  • United Healthcare (non-HMO) - ACD
  • United Healthcare (non-HMO) - PBO

Note: This provider may accept more insurance plans than shown; please call the practice to find out if your plan is accepted.

Patient Age Group

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Research & Publications

Research Summary
My research focuses on the neurovascular responses, in particular as it relates to the pathological processes after brain trauma.  I am also interested in the actions of neuregulin-1, an endogenous growth factor, within the neurovascular unit.  NRG1 is known to be important in the function of neurons and glia, but its activity in endothelial cells is not as well defined.  My goals were to 1) determine whether NRG1 plays significant roles in the biology of brain microvascular endothelial cells; and 2) to investigate the neuroprotective potential of NRG1 in brain trauma.  Data from my experiments demonstrated that NRG1 has key functions in brain microvascular cells; in particular, NRG1 prevents endothelial hyper-permeability due to cytokine injury, a significant finding given the many pathological processes that stem from microvascular hyper-permeability during CNS and systemic illness. 

View my most recent publications at PubMed

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News & Events

  • Not Taking a Breath for Granted: Mikey's Story at FAC Grand Rounds

    At 3 months old, Mikey was diagnosed with laryngomalacia. This made it hard for him to breathe. It also meant that he might need surgery and a tracheotomy. On April 11, his parents, Katie and Michael, shared their family’s experience at this year’s Grand Rounds, sponsored by the Family Advisory Council at MassGeneral Hospital for Children (MGHfC).

  • Research of Josephine Lok, MD

    The microvascular endothelium is instrumental in many processes in the brain, including oxygen delivery, barrier function, and response to inflammation. After brain trauma, microvasculature disturbances lead to increased permeability, vasoconstriction, and capillary occlusion, events which amplify the primary insult. An understanding of these endothelial responses to injury is important in the investigation of neuroprotective strategies during brain injury. This topic forms one major area of my research.


Pediatric Critical Care Unit
55 Fruit Street
Boston, MA 02114-2696
Phone: 617-724-4380
Fax: 617-724-4391

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