Suitability of Labelled EDTA for Glomerular Renographic Examination

An investigation was made of 58 persons, 48 of which could be divided into the following main groups: control subjects; patients suffering from acute or chronic glomerulonephritis; and patients suffering from chronic pyelonephritis. The remainder were patients with various other diseases. Comparison of the 113mIn-EDTA and 115mIn-EDTA renograms with the glomerular filtration rate (GFR) estimated as endogenous creatinine clearances and with 131I-Hippuran renograms was made. Normal EDTA renograms did not correspond with normal values of the GFR in all cases and the abnormal results as well. In controls agreement in normal values of both examinations has been found in the majority of cases. In patients with glomerulonephritis the percentage of disagreement was highest. This supported our opinion that EDTA renograms do not indicate impairment in glomerular filtration only. In experiments the authors studied rats of the ''Whistar'' strain by means of dosimetric and histological investigations. Changes in the size of nuclei in epithelial cells of proximal convoluted tubules have been estimated. Rats weighing approximately 200 g received intravenously 0.25 ml of 51Cr edetic acid solution (specific activity 0.15 μCi/ml). The animals were killed at predetermined intervals and both kidneys removed for measurements. For histological purposes excisions from kidneys were fixed in cooled formol (1: 5 dilution), placed in paraffin, with haematoxylin and eosin used as a dye. The volumes of nuclei in epithelial cells in the proximal convoluted tubules were measured. This histophysiological test was chosen on the basis of many references. It has been proved that the size of a nucleus is dependent on the functional state of the given cell. Diagrams illustrate the similarity of dosimetric and caryometric measurements. In both cases the peak is reached in the second minute after 51Cr edetic acid' administration and a similar downward slope of the curves up to the 45th minute follows. Results of the hisotological measurements indicate that the epithelial cells in proximal convoluted tubules are active in transport of 51Cr edetic acid. (author)