For my fourth day at the National Toxicology Program, I continued to work with Dr. DeVito in the Predictive Toxicology and Screening Group. Early in the day, I attended a peer review session as an observer at the ten-headed microscope. The review consisted of a group of pathologists who gathered to make suggestions regarding the research of another pathologist. Reviews like this allow for research to be vetted and checked for accuracy before it is published, to avoid any controversial or misleading conclusions. The review session I attended was meant to confirm or reject diagnoses of cytoplasmic alterations, fibrosis, and bile duct hyperplasia in histopathology slides of rat livers exposed to different doses of dibutyl phthalate. Dibutyl phthalate is commonly found as a plasticizer in nail polish.
After looking at slides through the ten-headed microscope, without exactly knowing what I was looking for, I returned to my cubicle to begin reading about how to identify different lesions under a microscope. I learned that fibrosis appears as an increase in cell density at random areas, and hyperplasia appears an enlargement of the cells. Through my time at the ten-headed microscope, I have become accustomed to using the microscope and identifying key parts of the organ slices, such as the nucleus or cytoplasm of the cell.
Later, I joined Dr. DeVito in his office to discuss the numerous projects the Predictive Toxicology and Screening Group pursues. Dr. DeVito told me about the central challenge the National Toxicology Program Laboratory faces: testing thousands of chemicals efficiently and effectively. To combat this challenge, the group employs a variety of techniques. To group chemicals, Dr. DeVito and his lab use a logistical prediction model to determine the possible adverse effects a chemical may have on the body, so they know which areas they should focus their testing on. Their tests range from using donated human liver cells to stimulating cortex cells with electric charges. I also learned about some of the different animals used in the lab, such as infant zebrafish, to test for prenatal effects of the chemicals. Lastly, Dr. DeVito explained some of the research conducted in the Biomolecular Screening Branch, which uses robots and automation to screen thousands of chemicals at a time.
Finally, I observed an NIEHS fellow working with the spheroids Dr. DeVito and his lab created. She was testing the effects of six different chemicals, and three times per weeks she changes the growth medium and chemical doses in her wells using an automated pipette machine that can fill and mix the solutions in all 384 wells at once. I also learned about the constant threat of contamination in a lab, and the different safeguards used by the lab staff to prevent it.