We propose to establish a core facility at Brigham and Women's Hospital that would provide the laboratories of members of the user group with the capability of rapidly quantitating radioisotopic emissions, luminescence, absorption, and fluorescence from samples prepared in standard format 96 well microtiter plates. All of these capabilities would be provided by an integrated system combining a MicroBeta Trilux liquid scintillation and luminescence counter, a Tomtec 96-well plate harvester, and a Victor multilabel counter for fluorescence and photometric measurements (all components to be purchased from Wallac, Inc.). The core facility will be based in the Harvard Skin Disease Research Core Center (HSDRC) currently funded by NIAMS. The major users are primarily drawn from investigators that are currently affiliated with the HSDRC with laboratory space in the same building (Thom Research Building) in which the HSDRC laboratories are located. The major users come from the Departments of Medicine (Dermatology and Gastroenterology Divisions), and Surgery. The proposed system will incorporate features (such as multiple detectors within the counter and plate stackers) to provide rapid answers following unattended counting of microtiter plate- based assays. Interfacing of the proposed system to an existing ethernet network will allow the participating laboratories rapid and convenient access to their results. The major types of assays to be performed by members of the user group using the proposed core facility will be: (a) cell proliferation assays based on 3H-thymidine incorporation; (b) luminescent detection of luciferase as a reporter gene in transfection and transgenic mouse experiments; (c) 51Cr release assays for quantitation of cytotoxicity; (d) static adhesion assays using fluorescently labeled cells; (e) DNA quantitation by fluorometry; and (f) absorption measurements on enzyme immunoassays. Rapid and efficient counting of each of these assay types will enable users of the core facility to achieve a substantial boost in productivity and allow for timely completion of experiments. We also anticipate that the shared use of this instrumentation will provide new opportunities for interactions between investigators from the laboratories of the major users, which should in time lead to initiation of new interdisciplinary research projects.