Salmonella Research Today is a free monthly online journal that collates and summarizes the latest research about Salmonella, including details on salmonella typhimurium, food poisoning, infection, treatment. | ||||||||
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Positron emission tomography (PET) imaging of tumor-localized Salmonella expressing HSV1-TK.Soghomonyan SA, Doubrovin M, Pike J, Luo X, Ittensohn M, Runyan JD, Balatoni J, Finn R, Tjuvajev JG, Blasberg R, Bermudes D Departments of Neurology and Radiology, Memorial Sloan-Kettering Cancer Center, 1275 York Avenue, New York, NY 10021, USA. In order to noninvasively detect Salmonella delivery vectors within tumors, we used a genetically modified Salmonella, VNP20009, that expresses the herpes simplex thymidine kinase (HSV1-tk) reporter gene. VNP20009-TK were able to selectively localize within murine tumor models and to effectively sequester a radiolabeled nucleoside analogue, 2'-fluoro-1-beta-D-arabino-furanosyl-5-iodo-uracil (FIAU). A quantitative relationship between the level of radioactivity accumulated and the number of bacteria in tumor and different tissues was demonstrated. The in vivo accumulation of [14C]FIAU measured in tissue sample homogenates and sections were related to Salmonella number and to immunohistochemical bacterial staining, respectively. Quantitative autoradiography (QAR) revealed the relative intensity of [14C]FIAU accumulation in a tumor cross-section, demonstrating that the peripheral region of the tumor was significantly less active than internal regions. [124I]FIAU positron emission tomography (PET) and subsequent tissue radioactivity and bacterial concentration measurements were compared. A log-log relationship was found, and the PET images could identify multiple tumor sites. The ability to noninvasively detect Salmonella vectors by PET imaging has the potential to be conducted in a clinical setting, and could aid in development of these vectors by demonstrating the efficiency and duration of targeting as well as indicating the locations of tumors. Published 16 December 2004 in Cancer Gene Ther, 12(1): 101-8.
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