Lesions produced by the extravasation of urine from the upper urinary tract

We present six cases which illustrate the spectrum of clinical features, macroscopic findings and light microscopic findings of urine extravasation from the upper urinary tract. The early lesions are characterized macroscopically by an oedematous, glistening or gelatinous appearance to the renal perihilar and peripelvic fat. Light microscopically there is lipolysis with associated foamy macrophages, multinucleate giant cells and lymphocytes. Immunohistochemical staining for Tamm–Horsfall protein is strongly positive in the extracellular space and in the foamy macrophages confirming urine extravazation. Later lesions are characterized by cicatrization of fibrous tissue around the renal pelvis and hydronephrosis. Microscopically there is relatively bland fibrosis with occasional lymphocytes and histiocytic cells. The late lesions are also characterized by extracellular deposits of weakly eosinophilic, granular or hyaline material, the so called 'urinary precipitates'. These deposits stain strongly with diastase PAS and weakly positive for Tamm–Horsfall protein. The staining of these urinary precipitates is analogous to renal tubular hyaline casts, thus supporting the theory that they are derived from uroproteins. We consider that these deposits are pathognomic of past urine extravasation.     

Measurement of airborne proteins involved in Bakers' asthma

Abstract. We have developed a competitive inhibition immunoassay to measure airborne flour, using purified polyclonal rabbit IgG antibodies to cereal flour antigens. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) showed different flours contained proteins of molecular weight similar to those present in air sample eluates. Western blotting demonstrated that the purified rabbit IgG antibodies bound to proteins whose molecular weights are similar to human allergens. Air sample eluates obtained from a large bakery had slopes of inhibition parallel to cereal flour when compared in the immune-inhibition assay. The assay identified airborne proteins from several flours with a detection limit of I μg ml^-1. Using this immunoassay we have shown that a wide range of airborne flour concentrations occur in flour mills and a smaller range bakeries. This assay which allows measurement of the concentration of Hour aeroallergen in the workplace will be valuable both in epidemiological studies and in examining the effectiveness of interventions to reduce the concentration of flour in the air.