Tubule recovery after obstructive nephropathy relief: the value of enzymuria and microproteinuria.

The recovery of tubules after relief of obstructive nephropathy may be investigated through serial assessment of the urinary excretion of tubular enzymes alpha-glucosidase, gamma-glutamyl-transferase and N-acetyl glucosaminidase as well as of the microprotein beta-2-microglobulin. We studied 21 patients in whom obstructive nephropathy was relieved by operative or nonoperative methods. Anuria persisted from 2 to 14 days. In these patients urinary excretion of alpha-glucosidase, gamma-glutamyl-transferase, N-acetyl glucosaminidase and beta-2-microglobulin, as well as the serum creatinine were assessed weekly. Serum creatinine was the earliest index to return to normal (within 9 to 26 days). Enzymuria returned to normal within 35 to 45 days, whereas normal urinary excretion of beta-2-microglobulin occurred more than 100 days after relief of obstructive nephropathy. N-acetyl glucosaminidase and gamma-glutamyl-transferase proved to be more reliable than alpha-glucosidase in detecting recovery of the luminal membrane of the proximal tubule. The return to normal of urinary beta-2-microglobulin levels has been shown to occur later, since more specific and complex intracellular functions underlie this index. The pathophysiological aspects of recovery of obstructive nephropathy may be considered similar to those observed in ischemic acute renal failure, since in both instances hemodynamic changes are involved.

[Renal contrast radiography study in hypertensive patients: comparison of the nephrotoxicity of ionic and non-ionic contrast media]. / L'indagine contrastografica renale nel paziente iperteso: confronto della nefrotossicità tra mezzi di contrasto ionici e non ionici.

The results of a study carried out on 32 patients with arterial hypertension about nephrotoxic effect obtained with a new non-ionic contrast agent have been reported. The diagnostic approach was based on the determination of the urinary excretion of two characteristic enzymes of the proximal tubule-epithelial cells (alfa-glycosidase and gamma-glutamil-transferase) and of a microprotein (beta-2-microglobulin) filtered by glomeruli and readsorbed and catalized by epithelial cells. The method used show an increased sensitivity and reliability in the early recognition of a kidney damage as well as in the control of anatomic and functional changes, in comparison with the classic parameters (azotemia, creatininemia). The results show a significantly lower enzymuric and microproteinuric level using non-ionic contrast media, also, in the patients at relatively higher risk of kidney damage. This results should be interpreted in favour to a lower potential nephrotoxicity of non-ionic contrast media and their elective use in the patients with a higher risk of kidney damage.

Amniotic fluid beta 2-microglobulin (beta 2-m) as an index of fetal maturity.

Amniotic fluid beta 2 microglobulin (beta 2-m) levels were measured by radioimmunoassay in 78 pregnant women between the 14th and the 42nd week of gestation. 62 were healthy subjects, while eight were affected by EPH gestosis, seven by diabetes (cl. B-F) associated with Rh immunization in one case, one by hydramnios. There was no significant correlation either between beta 2-m and creatinine (n = 18), or between beta 2-m and lecithin sphingomyelin ratio (L/S) (n = 16), although low concentrations of beta 2-m were usually observed after the 35th week of gestation. It is noteworthy that only in one case out of seven with amniotic levels less than 5 microgram/ml L/S ratio was less than 2.

Erythrocytes and "vinca rosea" alkaloids. An in vitro study.

The reported stereoscan images have proved that overtherapeutic amounts of vincristine induce in normal red cells the same effects as vinblastine, i.e. the onset of spherocytosis (in about 30% of the cells) and spherostomatocytosis (in the remainder) associated with distinct smaller vacuoles surrounding the larger cavity. The lowest deformation-inducing doses have been found to be twice as high for vincristine as for vinblastine (0.6mM); this is probably due to the greater interaction of the latter drug (because of its methyl group) with the bilayer phospholipids. Unlike previous reports, the present findings have revealed that the onset of red cell deformation is energy independent, since the same aspects have been recorded in both young and old erythrocytes. Therefore, such deformations must be considered the morphological consequence of a drug-induced mechanical derangement of the membrane subunits. In drug-incubated normal erythrocytes it was found that (a) neither drug exerts any influence on the intraglobular energy production and/or utilization, (b) osmotic fragility is enhanced, and (c) potassium leak is increased. These findings may be considered convincingly consistent with the assumption of a drug-induced mechanical derangement of the bilayer components.