Page 327 - 2014 Printable Abstract Book
P. 327
of BARDA currently sponsors six projects using several detection technologies to demonstrate their
varying utility in readily accessible biological specimens. These projects include a lymphocyte
cytokinesis -block micronuclei assay, proteomic and gene expression profiles of blood samples, and
electron paramagnetic resonance of incisor teeth. Human and non-human primate samples have been
evaluated and biomarker panels have been identified. The on-going progress of the projects in their
validation efforts will be reviewed. Development and scientific challenges in achieving sufficient accuracy,
specificity and reproducibility to ensure effective and appropriate use of medical countermeasures will be
presented.
(PS6-05) Developing an ex vivo EPR fingernail dosimetry method: contribution of UV light to the
2
2
2
1
background signal. Steven G. Swarts ; Andres E. Ruuge ; Dmitriy S. Tipikin ; Michael Mariani ; Dean E.
2
2
3
1
2
2
3
Wilcox ; Jiang Gui ; Stephen D.P. Marsh ; Oleg Grinberg ; Jason W. Sidabras ; Shiv Varansi ; Ann B. Flood ;
1
4
and Harold M. Swartz , University of Florida Shands Cancer Center, Gainesville, FL ; Geisel School of
3
2
Medicine at Dartmouth, Hanover, NH ; Medical College of Wisconsin, Milwaukee, WI ; and Geisel School
4
of Medicine at Dartmouth, Hanover, FL
The key to the success of electron paramagnetic resonance (EPR) dosimetry using human
fingernail clippings is the ability to obtain detailed characterizations of not only the radiation-induced
signals (RIS), but also the interfering mechanically-induced and background signals. The characterization
of these signals is important for the successful use of multi-component EPR spectral analysis methods to
differentiate and quantify the RIS from the complex spectrum in clipped fingernails. Currently, good
modeling of the individual mechanically-induced signals (MIS) and RIS spectral elements have been
achieved, providing a robust method for the fitting of these spectral elements to the EPR spectra of the
irradiated nail clipping. However, one spectral element that needs to be further defined is the background
signal. Although the spectral parameters of the background signal are well characterized there is the
remaining variability of this signal between individuals that needs to be further characterized so as to
better differentiate the background from the RIS and therefore provide precise measures of the RIS
intensities that are then used in calculating dose estimates. Characterization of demographic and external
variables as sources of variability in the nail background signals is currently being explored. Expanded
studies of the background signal in nail clippings are presently ongoing to provide the data necessary for
multi-variate analysis of the role of gender, age and race. One additional variable that is being explored is
the contribution of UV light to the background signals. We have evidence that exposure of nail clippings
and nail plates in vivo to UVA and UVB produces a signal that is similar to the background signal in nails.
Multi-frequency EPR techniques and nail treatment methods are being explored as possible approaches
to differentiate and minimize the UV-induced signal components within the background signal.
Longitudinal studies of nails collected from healthy donors are also being conducted to determine
seasonal and life-style differences in the UV-induced contributions to the nail background signal. The
progress that is being made towards characterizing the UV-induced signals in nails, and the contribution
of these signals to the background, will be presented.
325 | P a g e
varying utility in readily accessible biological specimens. These projects include a lymphocyte
cytokinesis -block micronuclei assay, proteomic and gene expression profiles of blood samples, and
electron paramagnetic resonance of incisor teeth. Human and non-human primate samples have been
evaluated and biomarker panels have been identified. The on-going progress of the projects in their
validation efforts will be reviewed. Development and scientific challenges in achieving sufficient accuracy,
specificity and reproducibility to ensure effective and appropriate use of medical countermeasures will be
presented.
(PS6-05) Developing an ex vivo EPR fingernail dosimetry method: contribution of UV light to the
2
2
2
1
background signal. Steven G. Swarts ; Andres E. Ruuge ; Dmitriy S. Tipikin ; Michael Mariani ; Dean E.
2
2
3
1
2
2
3
Wilcox ; Jiang Gui ; Stephen D.P. Marsh ; Oleg Grinberg ; Jason W. Sidabras ; Shiv Varansi ; Ann B. Flood ;
1
4
and Harold M. Swartz , University of Florida Shands Cancer Center, Gainesville, FL ; Geisel School of
3
2
Medicine at Dartmouth, Hanover, NH ; Medical College of Wisconsin, Milwaukee, WI ; and Geisel School
4
of Medicine at Dartmouth, Hanover, FL
The key to the success of electron paramagnetic resonance (EPR) dosimetry using human
fingernail clippings is the ability to obtain detailed characterizations of not only the radiation-induced
signals (RIS), but also the interfering mechanically-induced and background signals. The characterization
of these signals is important for the successful use of multi-component EPR spectral analysis methods to
differentiate and quantify the RIS from the complex spectrum in clipped fingernails. Currently, good
modeling of the individual mechanically-induced signals (MIS) and RIS spectral elements have been
achieved, providing a robust method for the fitting of these spectral elements to the EPR spectra of the
irradiated nail clipping. However, one spectral element that needs to be further defined is the background
signal. Although the spectral parameters of the background signal are well characterized there is the
remaining variability of this signal between individuals that needs to be further characterized so as to
better differentiate the background from the RIS and therefore provide precise measures of the RIS
intensities that are then used in calculating dose estimates. Characterization of demographic and external
variables as sources of variability in the nail background signals is currently being explored. Expanded
studies of the background signal in nail clippings are presently ongoing to provide the data necessary for
multi-variate analysis of the role of gender, age and race. One additional variable that is being explored is
the contribution of UV light to the background signals. We have evidence that exposure of nail clippings
and nail plates in vivo to UVA and UVB produces a signal that is similar to the background signal in nails.
Multi-frequency EPR techniques and nail treatment methods are being explored as possible approaches
to differentiate and minimize the UV-induced signal components within the background signal.
Longitudinal studies of nails collected from healthy donors are also being conducted to determine
seasonal and life-style differences in the UV-induced contributions to the nail background signal. The
progress that is being made towards characterizing the UV-induced signals in nails, and the contribution
of these signals to the background, will be presented.
325 | P a g e
