John M Virostko

Learn More
We developed a mouse model that enables non-invasive assessment of changes in β cell mass. We generated a transgenic mouse expressing luciferase under control of the mouse insulin I promoter [mouse insulin promoter-luciferase-Vanderbilt University (MIP-Luc-VU)] and characterized this model in mice with increased or decreased β cell mass and after islet(More)
PURPOSE To evaluate noninvasive molecular imaging methods as correlative biomarkers of therapeutic efficacy of cetuximab in human colorectal cancer cell line xenografts grown in athymic nude mice. The correlation between molecular imaging and immunohistochemical analysis to quantify epidermal growth factor (EGF) binding, apoptosis, and proliferation was(More)
We generated a mouse model (MIP-Luc-VU-NOD) that enables non-invasive bioluminescence imaging (BLI) of beta cell loss during the progression of autoimmune diabetes and determined the relationship between BLI and disease progression. MIP-Luc-VU-NOD mice displayed insulitis and a decline in bioluminescence with age which correlated with beta cell mass, plasma(More)
BACKGROUND Pancreatic islet transplantation is an emerging therapy for type 1 diabetes, but it is difficult to assess islets after transplantation and thus to design interventions to improve islet survival. METHODS To image and quantify islets, the authors transplanted luciferase-expressing murine or human islets (by adenovirus-mediated gene transfer)(More)
The ability to image the pancreatic islet in vivo would enhance our understanding of diabetes and accelerate improvements in islet transplantation. However, the small size of islets and their diffuse distribution (both natively and after transplantation) present formidable challenges for current imaging techniques. This article reviews the relative merits(More)
PURPOSE Metastasis, the main cause of death from cancer, remains poorly understood at the molecular level. EXPERIMENTAL DESIGN Based on a pattern of reduced expression in human prostate cancer tissues and tumor cell lines, a candidate suppressor gene (SPARCL1) was identified. We used in vitro approaches to determine whether overexpression of SPARCL1(More)
o fl a m c e n F e o o b t P ecent advances in several imaging modalities have improved noninvasive assessment of the pancreas in reclinical animal models and have enabled sequential tudies in the same animal, permitting dynamic studies f pancreatic disease. This review outlines progress in the pplication of small animal imaging to monitor the panreatic(More)
BACKGROUND Type 2 diabetes results from failure of the β-cells to compensate for increased insulin demand due to abnormal levels of metabolic factors. The ob/ob(lep-/-) mouse has been extensively studied as an animal model of type 2 diabetes. Previous studies have shown a correlation between β-cell function and bioluminescent imaging in lean genetically(More)
Purpose: In diabetes, pancreatic beta cell mass declines significantly prior to onset of fasting hyperglycemia. This decline may be due to endoplasmic reticulum (ER) stress, and the system L amino acid transporter LAT1 may be a biomarker of this process. In this study, we used 5-(2- 18F-fluoroethoxy)-L-tryptophan ( 18F-L-FEHTP) to target LAT1 as a potential(More)
In diabetes, pancreatic beta cell mass declines significantly prior to Purpose onset of fasting hyperglycemia. This decline may be due to endoplasmic reticulum (ER) stress, and the system L amino acid transporter LAT1 may be a biomarker of this process. In this study, we used 5-(2F-fluoroethoxy)-L-tryptophan ( F-L-FEHTP) to target LAT1 as a potential(More)