Studies with Radioactive Di-azo Dyes. 1. the Localization of Radioactive Di-brom Trypan Blue in Inflammatory Lesions.

The localization of circulating colloidal dyes in areas of increased capillary permeability, and their ingestion there by phagocytic cells, has been under investigation for the past 30 years. First observed by Goldmann (1) during his early studies with the vital stains, it later became the subject of study by investigators working with the inflammatory process, who found that many types of inflammation caused sufficient increase in permeability of the capillaries to produce local accumulations of dye (2, 3, 4). Evans (5) described the macrophage system as a separate entity as a result of its delineation by such dyes, following an extensive study of the intra-vitam reactions of many dyes of the benzidine series, such as trypan blue (6). More recently, many workers (7 to 10) have used dyeaccumulation as an index of the extent of permeability changes following injections of various irritants, fractions of inflammatory exudates, or organ-extracts, in an effort to elucidate the details of the inflammatory sequence. Burrows (11) provides an excellent review of the work in this field prior to 1932. Keith, Rowntree and Geraghty (12) explored the use of colloidal dyes in blood-volume determinations, this application arising from the fact that many of the acid azo dyes remain intravascular for fairly prolonged periods of time, and appear to form a bond with plasma protein (13). They, and others who followed in the same field (Dawson, Evans and Whipple (14), and Gregerson, Gibson and Stead (15)) have added much to our knowledge of the intravascular reactions of the dyes through their quantitative observations on serum concentrations, rates of elimination from the blood stream, and toxicity. Through this