OBJECTIVETo study the stomach role in exogenous oxalate absorption.

METHODSThe kinetic variation of urinary oxalate excretion (mg/min) in 10 healthy adults and 8 patients who underwent total gastrectomy was investigated before and after an oral spinach oxalate load. The bioavailability of the oxalate load in the healthy adults was calculated and compared with that in the patients.

RESULTSThe oxalate content in the oral spinach load was 2567-2670 mg. The urinary oxalate excretion (mg/min) in the 10 healthy adults increased significantly 20 minutes after loading (this increase was compared against their basic oxalate excretion level of 0.0331 +/- 0.0203). Further observations after loading include: a first peak of oxalate excretion 40 minutes after loading; an oxalate excretion level double that of the basic level after 60 minutes (0.0732 +/- 0.0294) and a second peak appearing at 3 hours (P < 0.01). A "first peak" (0.063% +/- 0.062%) was not in any of the patients who underwent a total gastrectomy. Furthermore, a bioavailability of oxalate, which was 50% lower than that in the healthy subjects, appeared 60 minutes after loading (0.098% +/- 0.071%, P < 0.01).

CONCLUSIONSThe stomach is a powerful oxalate absorption organ under normal physiological conditions. Further investigation on the relationship between stomach dysfunction and urinary calcium oxalate formation is needed.

Absorption ; Adult ; Female ; Humans ; Male ; Middle Aged ; Oxalates ; pharmacokinetics ; Spinacia oleracea ; metabolism ; Stomach ; metabolism

We characterized and compared the characteristics of Ca2+ movements through the sarcoplasmic reticulum of inferior oblique muscles in the various conditions including primary inferior oblique overaction (IOOA), secondary IOOA, and controls, so as to further understand the pathogenesis of primary IOOA. Of 15 specimens obtained through inferior oblique myectomy, six were from primary IOOA, 6 from secondary IOOA, and the remaining 3 were controls from enucleated eyes. Ryanodine binding assays were performed, and Ca2+ uptake rates, calsequestrins and SERCA levels were determined. Ryanodine bindings and sarcoplasmic reticulum Ca2+ uptake rates were significantly decreased in primary IOOA (p < 0.05). Western blot analysis conducted to quantify calsequestrins and SERCA, found no significant difference between primary IOOA, secondary IOOA, and the controls. Increased intracellular Ca2+ concentration due to reduced sarcoplasmic reticulum Ca2+ uptake may play a role in primary IOOA.
Sarcoplasmic Reticulum Calcium-Transporting ATPases ; Sarcoplasmic Reticulum/*metabolism ; Ryanodine Receptor Calcium Release Channel/metabolism ; Ryanodine/metabolism ; Oxalates/metabolism ; Oculomotor Muscles ; Ocular Motility Disorders/*metabolism/*pathology ; Muscles/*pathology ; Models, Statistical ; Middle Aged ; Male ; Humans ; Female ; Child, Preschool ; Child ; Calsequestrin/metabolism ; Calcium-Transporting ATPases/metabolism ; Calcium/metabolism/*pharmacokinetics ; Blotting, Western ; Aged ; Adult ; Adolescent