caa a22 4500 475742583 CHVBK 20180406123504.0 cr unu---uuuuu 170329e20000601xx s 000 0 eng 10.1007/s002400000101 doi (NATIONALLICENCE)springer-10.1007/s002400000101 Ascorbic acid in idiopathic recurrent calcium urolithiasis in humans - does it have an abettor role in oxalate, and calcium oxalate crystallization? [Elektronische Daten] [P. O. Schwille, A. Schmiedl, U. Herrmann, M. Manoharan, J. Fan, V. Sharma, D. Gottlieb] The role of ascorbic acid (ASC) in the pathophysiology of renal calcium stones is not clear. We evaluated ASC in blood and urine of fasting male patients with idiopathic calcium urolithiasis (ICU) and healthy volunteers. Using smaller subgroups, we also evaluated their response to exogenous ASC [either intravenous or oral ASC (5 mg/kg bodyweight)] administered together with an oxalate-free test meal. The influence of ASC on calcium oxalate crystallization, the morphology of crystals at urinary pH 5, 6 and 7, and the effect of increasing duration of urine incubation on urinary oxalate at these pHs, without and with addition of ASC, were studied too. In normo- and hypercalciuric ICU, blood and urinary ASC from fasting patients remained unchanged, but the slope of the regression line of urinary ASC versus urinary oxalate was steeper than in the controls; the plasma ASC half-life did not differ between controls, normo- and hypercalciuric ICU; the ASC-supplemented meal caused an increase in the integrated plasma oxalate in the normocalciuric subgroup versus controls. In normo- and hypercalciuric ICU urinary oxalate, the oxalate/glycolate ratio, and calcium oxalate supersaturation were increased, but urinary glycolate was unchanged. In the controls, oral ASC did not affect calcium oxalate crystallization, while in ICU, ASC inhibited crystal growth. In control urine calcium oxalate dihydrate and calcium oxalate monohydrate develops, while in ICU urine only the former crystal type develops. In vitro oxalate neoformation from ASC did not occur. It was concluded that (1) under normal conditions an abettor role of ASC for renal stones is not recognizable, (2) in ICU, urinary oxalate excess unrelated to degradation of exogenous ASC is exhibited, and that this is most likely unrelated to an initial increase in oxalate biosynthesis, and (3) ASC appears to modulate directly calcium oxalate crystallization in ICU, although the true mode of action is still not known. Springer-Verlag Berlin Heidelberg, 2000 Key words Ascorbic acid nationallicence Load studies nationallicence Plasma and urinary oxalate nationallicence Urinary oxalate/glycolate nationallicence Calcium oxalate crystallization nationallicence ASC stability in urine nationallicence Schwille P. O. University Hospital - Department of Surgery, Maximiliansplatz 2, 91023 Erlangen, Germany, DE aut Schmiedl A. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut Herrmann U. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut Manoharan M. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut Fan J. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut Sharma V. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut Gottlieb D. Guest scientist from the Weizmann Institute, Department of Biochemistry, Rehovot, Israel, IL aut https://doi.org/10.1007/s002400000101 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s002400000101 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Schwille P. O. University Hospital - Department of Surgery, Maximiliansplatz 2, 91023 Erlangen, Germany, DE aut NATIONALLICENCE 700 1- Schmiedl A. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut NATIONALLICENCE 700 1- Herrmann U. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut NATIONALLICENCE 700 1- Manoharan M. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut NATIONALLICENCE 700 1- Fan J. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut NATIONALLICENCE 700 1- Sharma V. Mineral Metabolism and Endocrine Research Laboratory, Departments of Surgery and Urology, University of Erlangen, Germany, DE aut NATIONALLICENCE 700 1- Gottlieb D. Guest scientist from the Weizmann Institute, Department of Biochemistry, Rehovot, Israel, IL aut Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer