? ? We request funds towards the purchase of a Zeiss510/ NLO microscope with Ti:sapphire Chameleon laser. Five principle investigators from the Medical School comprise the major user group (Faden, Mueller, Pestell, Roman, Van Keuren) and 8 minor users are described including faculty from the Medical Center and the Undergraduate Campus. A total of 11 NIH-funded investigators will be supported by this application. Projects conducted by major users include: vital imaging of invasion in tissues by tumor or transgenic mammary epithelial cells; vital imaging in situ of mitochondrial function in liver; imaging temperature sensitive probes in skin; and imaging vasculogenesis in zebrafish. Minor projects include imaging the effects of stable chemotactic gradients on neuronal growth cones embedded in thick collagen gels; vital imaging of neurons and parasite infection in the gut; trafficking of G protein-coupled receptors in hypertension; live imaging of vacuolar pH within living malarial parasites; and supporting the research and educational mission of the Lombardi Comprehensive Cancer Center (LCCC) Microscopy and Imaging Shared Resource (MISR). The new microscope will be housed in the LCCC MISR. The Principle Investigator, Dr. Mueller, is an NIH funded tumor cell biologist and has been director of this facility since 1991. LCCC and Georgetown University have committed space, additional funding to meet the total purchase price and yearly service contract dollars to support the acquisition and maintenance of this instrument. Members of the major user group with microscopy expertise including the PI (Mueller) and a physicist with multiphoton expertise (Van Keuren) will be trained initially together with one of our full time MISR microscopists (Palchik). Mr. Palchik who has expertise in confocal and digital light microscopy will support use and training under the direction of Drs. Mueller and Van Keuren. The shared resource will perform associated administrative tasks including billing. Oversight will be provided by our 8 member advisory committee. In 2004, the Shared Resource was utilized by 60 investigators representing 15 departments in the Medical School and the Undergraduate Campus. MISR has an outstanding record in training. Each year since 1999, we have trained between 30- 40 LCC investigators to use the existing microscopes in the MISR. The Shared Resource is maintained by a combination of Cancer Center and grant support. Users contribute to the resource in the form of user charge back fees. There is no multiphoton microscope at Georgetown and animal imaging activities are severely curtailed as a result. ? ? ?