Life Sciences Commons^™

Urinary Glycosaminoglycans Are Selectively Included Into Calcium Oxalate Crystals Precipitated From Whole Human Urine, Koji Suzuki, Keiko Mayne, Ian R. Doyle, Rosemary L. Ryall

Scanning Microscopy

Urinary glycosaminoglycans are selectively included into calcium oxalate (CaOx) crystals precipitated from whole human urine: The presence of glycosaminoglycans (GAGs) in the organic matrix of urinary stones, and their known effects on CaOx crystallization have prompted speculation regarding their role in CaOx urolithiasis. The aim of this study was to examine the involvement of GAGs in the early stages of CaOx crystallization in human urine. Urine samples were collected from healthy men and CaOx crystallization was induced by the addition of a sodium oxalate load. The crystals were harvested and demineralized, and the GAG content of the resulting extract analysed …

Etiology Of Experimental Calcium Oxalate Monohydrate Nephrolithiasis In Rats, W. C. De Bruijn, E. R. Boevé, P. R. W. A. Van Run, P. P. M. C. Van Miert, J. C. Romijn, C. F. Verkoelen, L. C. Cao, F. H. Schröder

Scanning Microscopy

In a rat-model system, tubular crystal retention as a possible mechanism for the etiology of nephrolithiasis in man, was studied by conventional transmission electron microscopy. The animals were supplied for nine days with a crystal-inducing diet, with ethylene glycol plus NH₄Cl in their drinking-water. After this induction period, a two day regime with fresh drinking-water was included, to allow crystals to be removed by spontaneous crystalluria. After aldehyde fixation of the rat kidneys, large crystals were seen inside the tubular lumen. The crystals were attached to cell surfaces and covered by neighboring epithelial cells. Some crystals were overgrown …

Effect Of Urinary Macromolecules And Chondroitin Sulphate On Calcium Oxalate Crystallization In Urine, A. L. Rodgers, D. Ball, W. Harper

Scanning Microscopy

After filtration and ultrafiltration (10 kD) of 24 hour urine specimens from 12 healthy male subjects, calcium oxalate crystallization was induced in the filtered (FILTD) and ultrafiltered (UF) fractions by administration of a sodium oxalate load. In addition crystallization was also induced in UF fractions to which physiological quantities of chondroitin sulphate (CHON) had been added (UF + CHON). The rate of calcium oxalate crystallization was determined by measuring the rate at which turbidity increased. Crystal numbers and sizes were measured with a Malvern particle size analyzer and by scanning electron microscopy.

Crystallization rates, crystal numbers and crystal sizes were …

Crystallization Of Calcium Oxalate And Calcium Phosphate At Supersaturation Levels Corresponding To Those In Different Parts Of The Nephron, Ján Lupták, Hanne Bek-Jensen, Anne-Marie Fornander, Inge Höjgaard, Mari-Anne Nilsson, Hans-Göran Tiselius

Scanning Microscopy

The risk of crystallization in solutions, with a composition corresponding to that of urine in various parts of the nephron, was assessed by studying urine samples containing standardized increments of calcium and oxalate concentrations. The experiments were carried out in salt solutions with and without dialysed urine and the appearance of crystals was detected and measured with a Coulter counter. With increased concentrations of calcium, crystals of calcium phosphate were predominantly formed in solutions with a composition corresponding to that in the proximal and distal tubuli, whereas, calcium oxalate was the primary crystallization product in solutions with a composition corresponding …

Effects Of Acute Acid Loading On The Risk Of Calcium Phosphate And Calcium Oxalate Crystallization In Urine, P. J. Osther, J. Bollerslev, J. R. Nørgård, K. Engel, P. Kildeberg

Scanning Microscopy

The aim of this study was to examine the risk of calcium phosphate and calcium oxalate crystallization during acute acid loading under controlled conditions.

The effects of acute acid loading on rates of renal excretion of calcium, magnesium, phosphate, citrate, oxalate and urine pH were studied in healthy subjects. The risk of calcium phosphate and calcium oxalate crystallization were evaluated by estimates of the ion activity products of calcium phosphate [AP(CaP)-index] and calcium oxalate [AP(CaOx)-index] according to Tiselius. In addition, the risk of brushite [AP(Bru)-index] crystallization was estimated.

An acute acid load administered as ammonium chloride (NH₄Cl) produced …