BACKGROUND Hyperoxaluria is a major risk factor for kidney stone formation. Although urinary oxalate measurement is part of all basic stone risk assessment, there is no standardized method for this measurement. METHODS Urine samples from 24-h urine collection covering a broad range of oxalate concentrations were aliquoted and sent, in duplicates, to six blinded international laboratories for ...

The microbial consumption of oxalate was examined under anaerobic conditions in soil suspensions at 15-20 degrees C. With soil (horizon Ah, pH 6.4) from a beech forest, microbial consumption of added oxalate (15mM) began after 10days, and oxalate was totally consumed by day 20. The presence of supplemental electron donors (acetate, glucose, vanillate, or hydrogen) or electron acceptors (nitrate...

Active transcellular oxalate transport in the mammalian intestine contributes to the homeostasis of this important lithogenic anion. Several members of the Slc26a gene family of anion exchangers have a measurable oxalate affinity and are expressed along the gut, apically and basolaterally. Mouse Slc26a6 (PAT1) targets to the apical membrane of enterocytes in the small intestine, and its deletio...

We describe a sensitive, simple technique for determining urinary oxalate. Urine, diluted as necessary with distilled water, is injected into an ion chromatograph. Oxalate is detected conductimetrically as a distinct peak near the tail of the chromatogram. This peak specifically represents oxalate, because it is abolished if the sample is treated with oxalate decarboxylase. We have used this te...

Intestinal oxalate transport, mediated by anion exchange proteins, is important to oxalate homeostasis and consequently to calcium oxalate stone diseases. To assess the contribution of the putative anion transporter (PAT)1 (Slc26a6) to transepithelial oxalate transport, we compared the unidirectional and net fluxes of oxalate across isolated, short-circuited segments of the distal ileum of wild...

Current treatment options for patients with hyperoxaluria and calcium oxalate stone diseases are limited and do not always lead to sufficient reduction in urinary oxalate excretion. Oxalate degrading bacteria have been suggested for degrading intestinal oxalate for the prevention of calcium oxalate stone. Here, we reported a recombinant Lactobacillus plantarum WCFS1 (L. plantarum) secreting het...

Diet is one of the primary drivers that sculpts the form and function of the mammalian gut microbiota. However, the enormous taxonomic and metabolic diversity held within the gut microbiota makes it difficult to isolate specific diet-microbe interactions. The objective of the current study was to elucidate interactions between the gut microbiota of the mammalian herbivore Neotoma albigula and d...

The measurement of oxalate in urine and plasma continues to be difficult, particularly in the presence of ascorbate. We have modified and validated a colorimetric assay involving the use of oxalate oxidase (EC 1.2.3.4). Modification of an HPLC spectrophotometric detector improved sensitivity (to as much as 1000-fold that of conventional spectrophotometers) and allowed measurement of oxalate con...

Serum oxalate rises in uremia because of decreased renal clearance, and crystals of calcium oxalate occur in the tissues of uremic patients. Crystal formation suggests that either uremic serum is supersaturated with calcium oxalate, or local oxalate production or accumulation causes regional supersaturation. To test the first alternative, we ultrafiltered uremic serum and measured supersaturati...

Nephrolithiasis remains a major health problem in Western countries. Seventy to 80% of kidney stones are composed of calcium oxalate, and small changes in urinary oxalate affect risk of kidney stone formation. Intestinal oxalate secretion mediated by the anion exchanger SLC26A6 plays an essential role in preventing hyperoxaluria and calcium oxalate nephrolithiasis, indicating that understanding...