Medicine and Health Sciences Commons^™

Diet And Toenail Arsenic Concentrations In A New Hampshire Population With Arsenic-Containing Water, Kathryn L. Cottingham, Roxanne Karimi, Joann F. Gruber, M Scot Zens, Vicki Sayarath, Carol L. Folt, Tracy Punshon, J. Steven Morris, Margaret R. Karagas

Dartmouth Scholarship

Background: Limited data exist on the contribution of dietary sources of arsenic to an individual's total exposure, particularly in populations with exposure via drinking water. Here, the association between diet and toenail arsenic concentrations (a long-term biomarker of exposure) was evaluated for individuals with measured household tap water arsenic. Foods known to be high in arsenic, including rice and seafood, were of particular interest.

Methods: Associations between toenail arsenic and consumption of 120 individual diet items were quantified using general linear models that also accounted for household tap water arsenic and potentially confounding factors (e.g., age, caloric intake, sex, smoking) …

Impact Of Treatment Response Metrics On Photodynamic Therapy Planning And Outcomes In A Three-Dimensional Model Of Ovarian Cancer, Sriram Anbil, Imran Rizvi, Jonathan P. Celli, Nermina Alagic, Brian W. Pogue, Tayyaba Hasan

Dartmouth Scholarship

Common methods to characterize treatment efficacy based on morphological imaging may misrepresent outcomes and exclude effective therapies. Using a three-dimensional model of ovarian cancer, two functional treatment response metrics are used to evaluate photodynamic therapy (PDT) efficacy: total volume, calculated from viable and nonviable cells, and live volume, calculated from viable cells. The utility of these volume-based metrics is corroborated using independent reporters of photodynamic activity: viability, a common fluorescence-based ratiometric analysis, and photosensitizer photobleaching, which is characterized by a loss of fluorescence due in part to the production of reactive species during PDT. Live volume correlated with both photobleaching …

An Mll-Dependent Network Sustains Hematopoiesis, Erika L. Artinger, Bibhu P. Mishra, Kristin M. Zaffuto, Bin E. Li, Elaine K. Y. Chung, Adrian W. Moore, Yufei Chen, Chao Cheng, Patricia Ernst

Dartmouth Scholarship

The histone methyltransferase Mixed Lineage Leukemia (MLL) is essential to maintain hematopoietic stem cells and is a leukemia protooncogene. Although clustered homeobox genes are well-characterized targets of MLL and MLL fusion oncoproteins, the range of Mll-regulated genes in normal hematopoietic cells remains unknown. Here, we identify and characterize part of the Mll-dependent transcriptional network in hematopoietic stem cells with an integrated approach by using conditional loss-of-function models, genomewide expression analyses, chromatin immunoprecipitation, and functional rescue assays. The Mll-dependent transcriptional network extends well beyond the previously appreciated Hox targets, is comprised of many characterized regulators of self-renewal, and contains target genes …

The Fungal Pathogen Aspergillus Fumigatus Regulates Growth, Metabolism, And Stress Resistance In Response To Light, Kevin K. Fuller, Carol S. Ringelberg, Jennifer J. Loros, Jay C. Dunlap

Dartmouth Scholarship

Light is a pervasive environmental factor that regulates development, stress resistance, and even virulence in numerous fungal species. Though much research has focused on signaling pathways in Aspergillus fumigatus, an understanding of how this pathogen responds to light is lacking. In this report, we demonstrate that the fungus does indeed respond to both blue and red portions of the visible spectrum. Included in the A. fumigatus light response is a reduction in conidial germination rates, increased hyphal pigmentation, enhanced resistance to acute ultraviolet and oxidative stresses, and an increased susceptibility to cell wall perturbation. By performing gene deletion analyses, we …

Dual-Tracer Background Subtraction Approach For Fluorescent Molecular Tomography, Kenneth M. Tichauer, Robert W. Holt, Fadi El-Ghussein, Scott C. Davis, Kimberly S. Samkoe, Jason R. Gunn, Frederic Leblond, Brian W. Pogue

Dartmouth Scholarship

Diffuse fluorescence tomography requires high contrast-to-background ratios to accurately reconstruct inclusions of interest. This is a problem when imaging the uptake of fluorescently labeled molecularly targeted tracers in tissue, which can result in high levels of heterogeneously distributed background uptake. We present a dual-tracer background subtraction approach, wherein signal from the uptake of an untargeted tracer is subtracted from targeted tracer signal prior to image reconstruction, resulting in maps of targeted tracer binding. The approach is demonstrated in simulations, a phantom study, and in a mouse glioma imaging study, demonstrating substantial improvement over conventional and homogenous background subtraction image reconstruction …