TITLE: Free-electron laser photoelectron emission microscopy studies of human pigment

SPEAKER: Professor John D. Simon,

TIME: Thursday Jan. 26, 2006 at 4:00 PM

PLACE: George P. Williams, Jr. Lecture Hall, (Olin 101)

Human pigments play an important role in controlling oxidative stress in human tissue. Melanin, a generic term to describe the dark pigments, mitigates such stress in the brain, eye, and skin. While all the pigments are grouped under a common name, the chemical properties of neuro, ocular, and skin melanin differ. It is reasonable to hypothesize the function of melanins differ among pigmented tissues and oxidative damage to these pigments can induce tissue-dependent biological responses. To understand how human melanins affect oxidative stress requires knowledge of the electrochemical properties of the surface of the intact pigment deposit and/or individual melanosomes. Adverse effects on neurological function or vision may result from localized damage to the pigments, and therefore the most desired information is spatially-dependent electrochemical properties of these specimens. FEL-PEEM is unique in its ability to obtain this information and can address biomedical problems that no other existing technology can probe. Specific applications include: to provide new insights into the etiology of neural degeneration observed in pigmented regions of the human brain through understanding of the spatially-dependent electrochemical properties of neuromelanin; to provide new insights into the etiology of macular degeneration by understanding the relationship between melanosomal damage and increased aerobic reactivity of ocular melanosomes in the retinal pigment epithelium (RPE); and determine the difference in oxidation potential between RPE melanosomes and the age-pigment lipofuscin. This talk will introduce the pigment field, report of chemical and structure studies used to characterize the pigments, and then present the current results from FEL-PEEM experiments and their implications.

100 Olin Physical Laboratory, 7507 Reynolda Station Wake Forest University Winston-Salem, NC 27109-7507 Phone: (336) 758-5337, FAX: (336) 758-6142 E-mail: wfuphys@wfu.edu	Quick Links Academics Research People Colloquia Info Physics