Webinar at a glance:
Moderated By: Dr. Mark Dewhirst, Gustavo S. Montana Professor of Radiation Oncology in the School of Medicine, Duke University
About the Speaker: Greg Palmer obtained his B.S. in Biomedical Engineering from Marquette University in 2000, after which he obtained his Ph.D. in BME from the University of Wisconsin, Madison. He is currently an Associate Professor in the Department of Radiation Oncology, Cancer Biology Division at Duke University Medical Center. His primary research focus has been identifying and exploiting the changes in absorption, scattering, and fluorescence properties of tissue associated with cancer progression and therapeutic response. To this end he has implemented a model-based approach for extracting absorber and scatterer properties from diffuse reflectance and fluorescence measurements. More recently he has developed quantitative imaging methodologies for intravital microscopy to characterize tumor functional and molecular response to radiation and chemotherapy. His awards have included the Jack Fowler Award from the Radiation Research Society.
About the Webinar: Hypoxia severely limits the efficacy of radiotherapy, chemotherapy, and immunotherapy. This results in diminished success in treating cancer. Despite consistent research in this field and treatments with promising anti-hypoxia mechanisms, there is no treatment for ameliorating hypoxia. This could be a result of ineffective hypoxia mitigators or because there is not a clinical imaging modality capable of directly quantifying oxygen at high temporal, spatial and oxygen resolution. Electron paramagnetic resonance oxygen imaging (EPROI) offers 3D oxygen maps at high resolution. The first, commercial, preclinical EPROI unit, JIVA-25 developed by O2M, is undergoing its final validation. At Duke University, this EPROI system is currently being utilized in radiation biology applications, investigating a promising radiation sensitizer in the E0771 murine flank tumor model: Oxygen microbubbles are venously-introduced and burst in the tumor via ultrasound, providing a bolus of oxygen. Preliminary in vitro data reports that an increase in tumor pO2 mere milliseconds before radiation significantly increases radiation-induced cancer cell damage. In vivo pilot studies have shown an increase in hemoglobin saturation in murine tumor models; however, to fully elucidate the role of oxygen microbubbles in alleviating hypoxia and to determine the ideal timing of prospective radiotherapy, the increase in tissue pO2 must be directly quantified spatially and temporally. We hypothesize that oxygen microbubbles will cause an acute increase in tumor pO2. Here, we present our initial data from this study. These described experiments, while focusing on the radiation biology field, will provide a preclinical imaging paradigm for quantifying hypoxia in vivo that is applicable to any research that requires precise evidence of tissue pO2.
Webinar at a glance:
Moderated By: Dr. David S. Kaplan, Microbiologist, FDA
About the Speaker: Dr. Simon is a biologist in the Biomaterials Group at the National Institute of Standards & Technology. He earned a B.S. in Biology from Bucknell University and a Ph.D. in Biochemistry from University of Virginia where his thesis focused on signal transduction during human platelet aggregation. He trained as a post-doctoral fellow in NIST Polymers Division, and became a staff scientist at NIST in 2003. He leads projects on cell-material interactions and tissue engineering scaffolds that support the development and characterization of tissue engineered medical products. Dr. Simon is Chair of ASTM Committee F04.43 “Cells and Tissue-Engineered Constructs” where documentary standards are being advanced to support the development of medical products. Dr. Simon is active in the Society for Biomaterials and is on the editorial board for “Biomaterials” and “Journal of Biomedical Materials Research Part B”.
About the Webinar: In the field of tissue engineering, 3D scaffolds and cells are often combined to yield constructs that are used as therapeutics to restore tissue function in patients. Viable cells are required to achieve the intended mechanism of action for the therapeutic, where the live cells may build new tissue or may release factors that induce tissue regeneration. Thus, there is a need to be able to reliably measure cell viability in 3D scaffolds as a quality attribute of tissue-engineered medical products. Measurements of cell viability in scaffolds are challenging because the scaffold interferes with the measurement. For soluble assays, the scaffold may impede diffusion of or physically interact with soluble reaction components. For imaging, the scaffold may interfere with photons, electrons or other particles being used to probe the system. Toward addressing this need, we are developing a model scaffold-cell-assay system that has been validated for a cell viability measurement. The system is composed of a polysaccharide hydrogel seeded with Jurkat cells with measurement of moles of ATP per gram of DNA. The reproducibility of the model system will be assessed by an inter-laboratory study and the results will be used to support an ASTM standard test method. In addition, we expect that the model scaffold-cell-assay system will be useful for assessing other methods for measuring cell viability in scaffolds, such as optical coherence tomography or electron paramagnetic resonance imaging.
Presenter: Dr. Mrignayani Kotecha, O2M Technologies
Date: December 11-15, 2020