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ABSTRACT: Glycolate and 2-phosphoglycolate (PG) are 2-carbon monocarboxylic acids with ill-defined metabolic roles. Their concentrations have not yet been described in tissues apart from body fluids and erythrocytes. We describe the use of ion chromatography coupled with mass spectrometry (IC-MS) to quantify levels of glycolate and PG in tissue. Sample preparation and analysis can be performed within an hour. Low concentrations of glycolate (12-48 nmol/g) and PG (4-17 nmol/g) were detected in all tissues. The availability of this IC-MS assay will facilitate investigations of the origin, function, and metabolism of glycolate and PG in tissues.
Analytical Biochemistry 10/2011; 421(1):121-4. · 3.00 Impact Factor
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Branden G Duffey,
Ricardo Miyaoka, Ross Holmes,
Dean Assimos,
Bryan Hinck,
Emily Korman,
Fred Kieley,
Sayeed Ikramuddin,
Todd Kellogg,
Angela Moeding,
Manoj Monga
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ABSTRACT: To establish the baseline preoperative prevalence of Oxalobacter formigenes (OF) colonization in a cohort of obese patients scheduled for Roux-en-Y gastric bypass (RYGB) and determine the effect of OF colonization on urinary oxalate excretion. It has been proposed that loss of OF colonization after RYGB may contribute to the development of hyperoxaluria.
Adult patients scheduled to undergo RYGB were requested to provide a stool specimen and 24-hour urine collection before surgery. OF colonization status was determined by the calcium precipitation test. The 24-hour urine specimens were analyzed by the Litholink Corporation (Chicago, IL).
Of the 51 patients submitting initial stool specimens, only 8 (16%) tested positive for OF, whereas 43 (84%) were negative. Patients colonized with OF were older than uncolonized subjects (52.9±6.8 vs 46.0±10.4 years, P=.03). Urinary oxalate was not significantly different between these groups (P=.14).
OF colonization is uncommon in morbidly obese patients (16%) before surgery. Because hyperoxaluria develops in more than 50% of patients after RYGB, it is unlikely that loss of OF colonization is the primary cause.
Urology 04/2011; 78(3):531-4. · 2.43 Impact Factor
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ABSTRACT: High animal protein intake is a risk factor for calcium oxalate stone disease. The effect of dietary protein on the urinary excretion of calcium, acid and citrate is well established. However, its effect on oxalate excretion is unclear, due in part to an inadequate control of dietary oxalate intake in previous studies. This relationship warrants clarification due to the proposed important role of the metabolism of amino acids in endogenous oxalate synthesis. In this study, 11 normal subjects consumed controlled oxalate diets containing 0.6, 1.2 and 1.8 g protein/kg body weight/day. The analysis of 24 h urine collections confirmed that as protein intake increased, urinary calcium and glycolate increased and urinary pH and citrate decreased. The increased glycolate excretion was due in part to an increased hydroxyproline, but not glycolate consumption. Total daily urinary oxalate excretion did not change. When indexed to creatinine there was a small but significant decrease in oxalate excretion. This is most likely due to hyperfiltration. These results indicate that as dietary protein intake increases, the catabolism of diet-derived amino acids is not associated with an increased endogenous oxalate synthesis in normal subjects.
Urological Research 02/2009; 37(2):63-8. · 1.23 Impact Factor
