Advances in imaging the kidney and cellular processes.

Researchers equipped with these unique and ever improving tools can utilize optical microscopy and digital image analysis to study subcellular events within cells, cell-cell interactions and integrative organ physiology, biochemistry, molecular and cellular biology. This will greatly enhance the understanding of physiologic and disease processes, developmental biology, and will hasten and improve the reliability and interpretation of preclinical data. Three major areas of development have now been combined to provide investigators studying the kidney with unique approaches to understanding biological processes in a renal specifi c fashion at cellular and subcellular levels. First, multiphoton microscopy offers the investigator a minimally invasive high-resolution technique with increased depth of penetration and markedly reduced phototoxicity for visualization of cellcell and intracellular events intravitally. The reduction in phototoxicity results as fl uorescence excitation occurs only at the focal point thereby eliminating out of focus fl uorescent excitation within the tissue as would occur with confocal microscopy. Second, improved detectors with increased sensitivity, enhanced software and faster hardware, and new computational algorithms for 3-D analysis and quantifi cation have allowed for more rapid, sensitive and accurate data gathering, visualization and interpretation. Finally, the revolution in fl uorophores capable of reporting on a growing number of cellular processes has markedly improved the capabilities available to the investigator. Fluorescent labeling of proteins, either by genetic or chemical means of attachment using a wide spectrum of colors, allows for simultaneous multiIntroduction