Dental caries is the breakdown of tooth enamel that causes cavities and is the most common chronic disease in children and adolescents between the ages of 6 and 19 years. Therefore, much work is being done to combat caries. We believe that the scanning fiber endoscope (SFE) developed in our lab can be used to improve the detection of early caries in children. The SFE is a small flexible probe that scans low-powered RGB laser light. It performs high-contrast high-resolution imaging and dual laser fluorescence spectroscopy with 405- and 532-nm laser excitation on both in vitro and in vivo teeth. My project focuses on the development of a calibration standard to use with the SFE in an upcoming clinical trial to be conducted at the UW Center for Pediatric Dentistry. A photostable calibration standard was created to match the fluorescence pattern of dental enamel. Spectral measurements of the standard will be taken before and after collecting data from patients' teeth with the SFE to monitor the instrument's behavior. This will allow us to account for drift in measurements and ensure that we can draw accurate conclusions from our data. 

The source and fate of hazardous material released into rivers and estuaries is critically important to protecting environmental health, especially in highly industrialized areas such as the Puget Sound. This study focuses on determining the legacy of heavy metal distribution (Pb-Cu-Zn-As) from a demolished ASARCO smelter site in north Everett, WA near the mouth of the Snohomish River. The Snohomish is a complex riverine system with many potential point and non-point sources of contaminants. This site is the target of remedial actions under the Model Toxics Control Act cleanup regulation developed by the Washington Department of Ecology due to widespread As and Pb contamination in the early 1900’s. Previous studies showed a correlation between heavy metal concentrations in benthic sediment of Possession Sound and proximity to industrial sites near the mouth of the Snohomish River. If the source is the ASARCO smelter, we should be able to trace Pb contamination downstream from the site. No data are available from within the river to constrain the specific sources of anthropogenic metals. In our study, we use Pb isotope variability between natural and anthropogenic Pb to establish the extent of dispersion of contaminants derived from ASARCO. The sample suite we collected consists of: three one-meter-long river-bottom sediment cores collected 1) near the mouth of the Snohomish River, 2) near the ASARCO site, and 3) up river to compare natural baseline values with near site and downriver sites; and 4) slag samples to serve as reference isotopic signature of ASARCO Pb. Purification of Pb from the samples is complete, and the isotopic analyses of the Pb are in progress utilizing an inductively coupled plasma mass spectrometer under the advisory of Dr. Bruce Nelson at the University of Washington. This research will identify spatial and temporal relationships among fluvial processes and Pb deposition.

The incidence of esophageal adenocarcinoma (EAC) is increasing world-wide. Early and specific detection of EAC and its precursor non-cancerous stages, particularly Barrett’s esophagus (BE), is crucial to treatment and long-term survival. Currently, endoscopy coupled with serial biopsy is the gold standard for diagnosis. Standard endoscopy lacks specificity. BE presents as a salmon-reddish discoloration against the pale-pink color of healthy esophageal tissue. Cardia intestinal metaplasia (CIM) arising from gastric tissue is visually similar; both develop in response to prolonged acid reflux and are often confused during histological analysis. However, CIM is unrelated or even negatively correlated to EAC development. Distinguishing between BE and CIM at the gastroesophageal junction is crucial to minimizing the use of invasive biopsy. Targeting molecular markers specific to disease state can enhance specificity. Fluorescent dyes attached to targeting molecules are used to label these biomarkers. Instrumentation designed for in-vivo fluorescent imaging, like the ultrathin, flexible, multimodal scanning fiber endoscope (SFE) can then excite and image the fluorescent dyes, effectively red-flagging abnormal regions for both enhanced biopsy capture and point-of-care diagnosis. Reliance upon one biomarker alone is ineffective due to patient heterogeneity, as expression varies between patients due to factors including genetic background and lifestyle. Multiple biomarkers are necessary for specificity. The purpose of our work is to first demonstrate that the three cell surface biomarkers, EGFR, C-MET, and ERBB2, well established in other cancers, are appropriate for early EAC or BE diagnosis. We plan to demonstrate the simultaneous application of all three biomarkers to provide added specificity and sensitivity for diagnosis and ultimately prognosis. These goals will be achieved through immunofluorescent staining of cell lines and paraffinized tissue samples excised from patients. The efficacy of using multiple markers will be assessed through image processing and statistical analysis.