TOTAL NONDIALYZABLE SOLIDS (TNDS) IN HUMAN URINE. IX. IMMUNOCHEMICAL STUDIES OF THE R-1 "UROMUCOID" FRACTION

The nature of urinary casts

The composition of hyaline casts has been investigated. The major constituent appears to be the urinary mucoprotein described by Tamm and Horsfall. Small amounts only of serum proteins are present. Neither the amounts excreted nor the concentration of Tamm-Horsfall protein appeared to determine the rate of cast formation. The only invariable association of hyaline cast formation was with the presence of significant amounts of serum proteins in the urine. In vitro it was found that aqueous solutions of serum albumin were particularly effective in producing precipitation of Tamm-Horsfall protein. This interaction was inhibited in normal urine but occurred to a greater extent in nephrotic urine and is suggested as the possible mechanism of hyaline cast formation.

THE ANTIGENIC COMPOSITION OF TUMOURS, SERA AND URINES OF TUMOUR-BEARING MICE AND THE PARTIAL PURIFICATION OF TWO ANTIGENS PRESENT IN INCREASED AMOUNTS

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Tumor necrosis factor in benign and malign tissue of the kidney

The use of tumor necrosis factor (TNF) in immunotherapy of tumor diseases has attracted increasing interest. Since the direct antitumor effect of the TNF is mediated by receptor-bound TNF, we immunohistologically stained both benign and malignant tissue from 35 tumor-bearing human kidneys for TNF. Using a polyclonal anti-TNF-antiserum, paraffin sections were tested in the presence and absence of in vitro preincubation with TNF. Furthermore, all specimens were stained immunohistologically for Tamm-Horsfall protein (THP) because this renospecific glycoprotein can bind TNF in a lectin-like manner. In the absence of TNF preincubation, malignant tissue was TNF-positive in 34 specimens, as was benign tissue from the same tumor-bearing kidneys in 35 cases. In several specimens the staining was so intense that preincubation with TNF did not enhance the reaction. Whereas TNF staining in tumor tissue was relatively homogenous, that in benign tissue was intensive in distal tubuli, moderate in proximal tubuli, and negative in glomeruli. THP staining was negative in malignant kidney tissue but positive in the distal tubuli of benign tissue, i.e., in the regions in which TNF staining was most intense. These results indicate that TNF binds not only to membrane, most likely in a receptor-mediated manner, but also to THP both in vivo and in vitro. In vivo binding of TNF to THP was confirmed in animal experiments in which pigs were given injections of TNF. Immunohistological staining of the animals' kidneys revealed positive reactions for both TNF and THP at the distal tubuli, indicating TNF binding to THP after in vivo TNF administration.(ABSTRACT TRUNCATED AT 250 WORDS)

Immunofluorescent localization of Tamm-Horsfall mucoprotein in human kidney

A fluorescein-labelled antiserum to human Tamm-Horsfall mucoprotein applied to frozen human kidney sections gave strong specific labelling, mainly of cells of tubules in the outer medulla. By comparison with adjacent serial sections stained for alkaline phosphatase and succinic dehydrogenase, it is suggested that material reacting immunologically as Tamm-Horsfall muco-protein is found particularly in the cells of the ascending limb of the loop of Henle and the macula densa segment of the distal tubule.