Eight NIH-funded investigators in the Division of Pulmonary and Critical Care Medicine and the Department of Pediatrics at the Northwestern University Medical School are seeking funds to obtain a Zeiss LSM510 META laser scanning confocal microscope in this proposal. Investigators in these departments are studying the mechanisms of apoptosis, signal transduction, fluid transport, and gene transfer in the alveolar epithelium and pulmonary vasculature. These studies involve localization of non-static proteins and nucleic acids in living cells, tissues, and whole animals. The Zeiss LSM510 META system offers fast image acquisition rates, high spatial resolution, and simultaneous monitoring of 10 wavelengths of emitted light via two PMTs and an 8-channel META detector. With 3 scans, 32 separate wavelengths can be acquired. The system will be configured around an upright Zeiss Axioplan 2 microscope equipped for laser based differential interference contrast (DIC) microscopy. The use of water-immersion objectives will allow investigators to image vital processes in living tissues and cells. At present, there is one modern confocal microscope (Zeiss LSM510) available to the entire research community at large on the Medical School campus of Northwestern University. However, its detector and scan head prevent the separation of several fluorescent signal combinations essential to most of the investigators in this proposal. Further, because this existing microscope is over-utilized, the purchase of another microscope would greatly relieve the current usage on the existing microscope and allow the researchers in this application sufficient access to the new microscope to complete their NIH-funded projects. The new microscope will be housed in a location central to the eight investigators and will be maintained and administered by the Cell Imaging Facility, directed by a full-time imaging specialist at the rank of Research Assistant Professor. The University has committed funds to purchase three years of service contracts and a fee for microscope time will be used to cover the cost of annual service contracts after the 4th year. It is essential that we obtain a confocal microscope to meet the needs of these investigators.