Research Project: Radiation Safety and Novel Radiation-Based Therapeutic Agents
Assessing the factors and conditions that effect safe exposure of humans to radiation is important to a number of FDA regulated products. The laboratory has a couple of research projects in this area, one in collaboration with our coworkers within the Division of Physics which investigates the effects of UVB and UVA1 on internal tissues that are not normally exposed to light, such as vaginal tissues, to determine if currently accepted UV doses, derived from external skin exposures, are acceptable. Another research area looks at the effects of sunscreens or cosmetics on the interaction of ultraviolet radiation with human skin. The use of radiation-based devices for cancer treatment is another area of interest were laboratory research efforts focus on furthering our knowledge to aid in ensuring the safety and effectiveness of these novel radiation-based therapeutics. Research projects here investigate the effectiveness of low energy X-rays for tumor treatment and the sensitization of human melanoma xenografts to thermoradiotherapy.
Measuring human response to ultraviolet radiation (UV). Small areas on the back are exposed to increasing UV doses minimal erythema (redness) dose is determined one day later, minimal pigmentation (tan) dose is determined one week later.
A graph showing the results of different races exposed to increasing UV doses minimal erythema (redness) dose.
UVA1 radiation kills transformed lymphocytes by initiating apoptosis rather than necrosis as shown in figure. Panels A and B represent the TEM images of sham-irradiated transformed human T and B lymphocytes, respectively while Panels C and D represent the UVA1-irradiated transformed human T and B lymphocytes, respectively. Apoptosis is the mode of cell death as shown by the following characteristic morphological and ultrastructural changes observed in the TEM images: cell shrinkage, membrane blebbing, formation of apoptotic bodies, dilation of rough endoplasmic reticulum (vacuoles), chromatin digestion and condensation along the nuclear membrane, and nuclear fragmentation.