The present study was undertaken to clarify the clinical significance of urinary fibrinjfibrinogen degradation products (U-FDP) measured by tanned red cell hemagglutination inhibition immunoassay in renal disease. The frequency of occurrence and the amount of U-FDP were examined. Also, the relationship of U-FDP to histological findings, urinary protein (U-P), serum FDP, and renal function were studied. In additicn, a trial of anticoagulant therapy to renal disease was evaluated. The results obtained are summarized as follows: 1) U-FDP was found in patients with post-streptococcal acute glomerulonephritis (AGN), chronic glomerulonephritis (CGN), membranous nephropathy (MN), and lupus nephritis, but absent in lipoid nephrosis. 2) A large amount of U-FDP was found frequently in cases with histologically proliferative change. 3) U-FDP did not correlate to U-P, but the relationship between U-FDP and U-P in each classified renal disease showed a characteristic pattern: A) In lipoid nephrosis and MN, a small amount of U-FDP was found in spite of a large amount of U-P. B) In AGN, a large amount of U-FDP but a small amount of U-P was measured. C) In CGN and lupus nephritis, the relationship between U-FDP and U-P was variable. 4) U-FDP did not correlate to serum FDP. 5) In cases with long-term positive U-FDP, their renal function (GFR and PSP) showed a tendency to decrease, in contrast to no such tendency in long-term negative cases. 6) Heparin reduced U-FDP remarkably, and improved the decreased GFR in cases with longterm positive U-FDP, although no such effect was observed in negative cases. In contrast, warfarin neither reduced U-FDP nor improved GFR in both cases with long-term positive and negative U-FDP. 7) Daily measurement of U-FDP was assessed to be of potential value in deciding heparin administration in renal disease. 8) The origin of U-FDP was discussed in relation to U-P

View full abstract

Studies utilizing in vitro microperfusion were designed to examine whether urea is actively or passively transported across superficial (SF) and juxtamedullary (JM) straight segments of raboit proximal tubules. With perfusate and bath solutions containig 1mM/L urea and electrolytes similar to normal plasma, the efflux isotopic permeability was low when compared to other nephron segments and significantly lower than the influx isotopic permeabiliity in both groups. Using a low perfusion rate (2 nl/min) and equivalent specific activities of ¹⁴C-urea in oath and perfusate, the collected to perfused ratio of ¹⁴C-urea, corrected for volume marker change, was 1.07±0.01 in SF and 1.09±0.1 in JM thus indicating net secretion in both segments. In separate studies urea influx was inhibited py hypothermia (decrease from 37°c to 28°c), by phloretin (10^-4 M in bath), ay cyanide (10.3 M in bath), but not ey probenecid (2±10^-4 M in bath), In each case the inhibition was significant (p<0, 001) and reversible. In summary, urea influx is greater than urea efflux when measured in the same tubule. The influx of urea is inhibited by hypothermia, phloretin and cyanide. This date strongly suggests that urea is actively secreted by the straight segments of ooth the SF and JM proximal tubule. These segments may therefore contribute significantly to the high urea concentration at the bend of Henle's loop by micropuncture.

View full abstract