photo of Tyson McDonald

J. Tyson McDonald, PhD

Adjunct Researcher
Center of Cancer Systems Biology

Mailing Address:
39 Tyler Street, Room 200
Cancer Research Center, Hampton University
Hampton, VA 02668   USA

Email: john.mcdonald [at]

Education and Training:

• PhD in Biomedical Physics, University of California Los Angeles
• BS in Nuclear Engineering, University of Michigan Ann Arbor

Research Description:

The classic outcomes of radiation exposure — like cell cycle arrest, apoptosis, and senescence — may form barriers to the introduction of genomic instability and cancer, but these are sometimes circumvented by cellular resistance mechanisms that may be up-regulated to enhance the probability of survival. Ionizing radiation is an exogenous stress that has powerful effects on cell death and multiple signaling pathways. The pathways that are activated within the signaling network therefore serve as targets for interventions aimed at controlling responses in potentially harmful environments. My research is focused on the long-term molecular effects of actue and chronic exposures to high and low-dose ionizing radiation.

Along with using commercially available cell cultures for in vitro studies, my research includes normal tissues from clinically indicated robotic-assisted laparoscopic radical prostatectomies. Tissues were grossly identified, sectioned into frozen or formalin fixed samples, and processed as primary cultures. Normal epithelial and fibroblast primary cell cultures were derived from regions of normal tissue, as confirmed by analysis on adjacent tissues by hematoxylin and eosin staining, and were exposed to actue doses of radiation from a Cesium-137 source (0.5cGy per min.) or chronic irradiation using a Cobalt-57 source (1–2cGy per day). The result of this research aims to uncover an appreciation of cell–cell signaling within a tissue microenvironment that is critical to understanding cellular response to low-dose ionizing radiation outside the realm of cell death.

(click on title to go to manuscript abstract)