Figure 1.
Adenosine diphosphatase (ADPase) activity and nonspecific esterase activity (red, indicating PMNs) in a diabetic retina (left). Bright-field (A) and dark-field illumination (B) and a section (C) after embedding in glycol methacrylate are shown for the same capillary segment (triple arrow). ADPase activity, an indicator of endothelial cell function,29 is lost at the site of PMN binding. When PMNs in retina were counted (D), there were significantly more PMNs in diabetic retina than in control subjects. Alkaline phosphatase activity (APase, blue) and nonspecific esterase (NSE) activity (red) in a normal choroid (E) and in a diabetic choroid (F). PMNs in the diabetic choroid are present at sites of choriocapillaris dysfunction, loss of APase activity (F).45 PMNs in diabetic and nondiabetic choroid were counted, and all areas of diabetic choroid had more PMNs than did normal choroid (G).43