radiopaque contrast media xliv preclinical studies with a new nonionic contrast agent l5alphahydroxypropionylamino246triiodoisophthalic acid di13dihydroxy2propylamide abbreviated iopamidol a new nonionic water soluble contrast agent for angiography myelography ventriculography and for contrast reinforced computerassisted axial tomography is described extensive preclinical testing showed favorable physicochemical features of the new compound low systemic toxicity excellent cardiovascular and renal tolerability very mild effects on the bloodbrain barrier and on nervous tissue onestep labeling of degenerative neurons in unfixed brain tissue samples using fluorojade c neurodegeneration is the underlying cause of a vast majority of neurological disorders and often a result of brain trauma stroke or neurotoxic insult here we describe a simple method for labeling degenerating neurons in unfixed brain tissue samples this method could provide a new avenue for identifying and harvesting degenerative neurons from unfixed brain tissues for subsequent molecular analyses