1,720,976 research outputs found
[Abnormalities in the erythrocyte membrane transport of oxalate in calcium oxalate lithogenesis].
No full textThe high incidence of a family history and the observation of abnormally high intestinal absorption and urinary excretion of oxalate suggest to consider idiopathic calcium oxalate nephrolithiasis as a metabolic disease characterized by a disorder in oxalate transport. To test this hypothesis, the flux of 14C Oxalate through the membrane of red blood cells was investigated in 24 calcium oxalate stone formers; 18 of the 24 "idiopathic" calcium oxalate stone formers showed an increased oxalate self exchange (75%). Our data seem to support the possibility that "idiopathic" calcium oxalate nephrolithiasis may be considered as a metabolic disease marked by a defect in transmembrane transport of oxalate
High urinary excretion of glycosaminoglycans: a possible marker of glomerular involvement in diabetes.
No full textMany insulin-dependent diabetic patients with albuminuria in the "not at risk range" for diabetic nephropathy present high urinary excretion rates of glycosaminoglycans. A lysine provocative test in these subjects disclosed abnormal urinary excretion of albumin, unlike findings obtained in insulin-dependent diabetic patients with normal urinary excretion rates of glycosaminoglycans. These data support the hypothesis that high urinary excretion of glycosaminoglycans is a marker of glomerular involvement in diabetes mellitus
Raised transmembrane oxalate flux in red blood cells in idiopathic calcium oxalate nephrolithiasis.
No full textRed-blood-cell transmembrane oxalate flux was measured in a group of patients with idiopathic calcium oxalate nephrolithiasis and in normal controls. The mean transmembrane oxalate flux rate was significantly higher in stone-forming patients than in controls (0.93 +/- SD 0.31/min vs 0.29 +/- 0.11/min). 80% of stone-forming patients showed raised (greater than 2SD above the mean in controls) transmembrane oxalate flux. Anomalous cellular oxalate transport may be an important pathogenetic factor in calcium oxalate nephrolithiasis
EFFECT OF ALKALINE CITRATE THERAPY ON CLEARANCE OF RESIDUAL RENAL STONE FRAGMENTS AFTER EXTRACORPOREAL SHOCK-WAVE LITHOTRIPSY IN STERILE CALCIUM AND INFECTION NEPHROLITHIASIS PATIENTS
No full textThe natural history of post-extracorporeal shock wave lithotripsy residual stone fragments (clearance, growth and aggregation) is incompletely known, even though they are believed to constitute a risk in terms of new stone formation and persistent infection of the urinary tract. We addressed this issue and the hypothesis that alkaline citrate therapy improves residual stone fragment clearance in a 12-month followup study. There were 40 sterile calcium and 30 struvite stone patients with residual fragments after extracorporeal shock wave lithotripsy (diameter less than 5 mm.) consecutively enrolled and randomly assigned to a citrate therapy (6 to 8 gm. per day) or control (hygienic measures only) group. Infection stone patients also received adequate antibiotic therapy throughout the study. Among the patients in the untreated sterile group 21% and 32% were stone-free at 6 and 12 months, respectively. In the infection group these figures were 27% and 40%, respectively. Among the untreated sterile calcium stone patients in whom clearance was not achieved a high percentage experienced residual fragment growth or reaggregation. Citrate therapy significantly improved the stone clearance rate in the sterile (at 6 and 12 months 65% and 74% were stone-free, respectively) and infection (71% and 86%, respectively) stone patients, and prevented residual fragment growth or reaggregation in subjects in whom clearance was not achieved. The data show that growth and persistence are common in the natural history of residual stone fragments. Citrate ameliorated the outcome of these residual fragments by reducing the growth or agglomeration, and by increasing the clearance rate in calcium oxalate and in infection stone patients
[Role of Tamm-Horsfall mucoprotein in calcium oxalate lithogenesis].
No full textTamm-Horsfall (TH) mucoprotein has been suggested to play a lithogenetic role in calcium-oxalate nephrolithiasis. However it is still debated whether it promotes or inhibits crystal growth and aggregation. To make clear the role played by this mucoprotein, we have carried out the following experiments: 1) the urinary excretion of TH has been evaluated by radial immunodiffusion in 27 recurrent idiopathic CaOx stone formers and in 35 controls; 2) in a metastable solution of CaOx the effect of TH addition on crystal growth has been monitored; 3) in whole urine the effect of TH addition on crystal aggregation has been assayed by an aggregometer. Urinary excretion of TH is significantly lower in stone formers. TH does not seem to promote crystal growth, while it is effective on crystal aggregation. These data seem to suggest that the reduced excretion of TH in nephrolithiasis may be a lithogenic risk factor
Urinary glycosaminoglycans, sialic acid and lysosomal enzymes increase in nonalbuminuric diabetic patients.
No full textUrinary excretion of glycosaminoglycans (GAGS) and sialic acid (SA), as well as the activity of two renal enzymes related to glycoprotein metabolism, N-acetyl-beta-D-glucosaminidase (NAG) and beta-galactosidase (GAL), and two others unrelated to glycosaminoglycans and glycoprotein metabolism, gamma-glutamyltranspeptidase (gamma-Gt) and angiotensin-I-converting enzyme (ACE), were evaluated in 40 insulin-dependent diabetic patients with normal range albuminuria, 21 patients with mesangial glomerulonephritis, and 30 control subjects. Diabetic and glomerulonephritic patients excreted a significantly higher amount of GAGS and SA, and showed greater NAG and GAL activities; gamma-Gt and ACE levels were within normal ranges. No correlation could be demonstrated between diabetes duration and GAGS, SA, NAG and GAL findings. Moreover, no correspondence between degree of metabolic control, as reflected by glycosylated hemoglobin (HbA1a-c) and GAGS, SA, NAG and GAL emerged
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