Experimentelle Untersuchungen zur Löslichkeitsbeeinflussung mineralischer Harnkonkremente

Knappwost, A.; Matouschek, E

doi:10.1159/000279822

Cited by 19 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Hammarsten's results [23] at 37 C are smooth; however, this author reported that her data were not consistent with the Debye-Hu Èckel law even at very low ionic strength. Knappwost and Matouschek's data [24] show a large scatter, some of them are lower and some are higher than the data from all other sources. The data of Ref.…”

Section: Commentioning

confidence: 79%

Solubility of the Three Calcium Oxalate Hydrates in Sodium Chloride Solutionsand Urine-Like Liquors

Streit

Tran‐Ho

Königsberger

1998

Monatshefte fuer Chemie

View full text Add to dashboard Cite

Calcium oxalate forms three hydrates (stable monoclinic mono-hydrate (COM), metastable tetragonal dihydrate (COD) and triclinic trihydrate (COT)), which are of medical importance in urinary calculi formation. In this work, the solubility of these calcium oxalate hydrates was determined at 20, 25, 30, 37, and 40 C in aqueous NaCl (0.02±0.20 mol Á dm À3 ) and in urine-like liquors. Also, for the ®rst time, the solubility of COM was systematically studied as a function of pH in arti®cial urine solutions which contain organic compounds. The concentrations of calcium ions were measured continuously using a calcium ion selective electrode and also determined by AAS. The thermodynamic solubility products were obtained from computer simulations in which all possible complexes formed in aqueous solution were taken into account. These values were compared to those available in the literature; it was found that the present results, especially for COD and COT, constitute a major improvement on the previously reported values. The constants determined in this work were used to predict the solubility of calcium oxalate hydrates at different pH in urine-like liquors. It was found that in arti®cial urine solutions, citrate and magnesium ions promote the solubility of COM, whereas urea and creatinine have no signi®cant effect. Lo Èslichkeit der drei Calciumoxalathydrate in Natriumchloridlo Èsungen und urina Èhnlichen Flu È ssigkeiten Zusammenfassung. Calciumoxalat bildet das stabile monokline Monohydrat (COM) sowie zwei metastabile Phasen, das tetragonale Dihydrat (COD) und das trikline Trihydrat (COT). Da die drei Calciumoxalathydrate bei der Entstehung von Nierensteinen eine wichtige Rolle spielen, wurde ihre Lo Èslichkeit bei 20, 25, 30, 37, und 40 C in NaCl-Lo Èsungen (0.02±0.20 mol Á dm À3 ) sowie in ku Ènstlichen Urinlo Èsungen, die zum Teil auch organische Substanzen enthielten, gemessen. In letzteren wurde die Lo Èslichkeit von COM als Funktion des pH-Werts erstmalig systematisch untersucht. Die Ca 2 -Konzentrationen wurden mit Hilfe einer ionenselektiven Elektrode sowie durch AAS bestimmt. Die thermodynamischen Lo Èslichkeitsprodukte wurden aus Computersimulationen erhalten, in denen die in der wa Èûrigen Lo Èsung vorkommenden Komplexe weitestgehend Ã Corresponding author beru Ècksichtigt wurden. Beim Vergleich dieser Gro Èûen mit Literaturwerten stellte sich heraus, daû insbesondere die Werte fu Èr COD und COT eine wesentliche Verbesserung gegenu Èber den bisherigen Daten darstellen. Die in dieser Arbeit ermittelten Lo Èslichkeitsprodukte wurden zur Berechnung der Lo Èslichkeit der Calciumoxalathydrate in ku Ènstlichem Urin verwendet. Es zeigte sich, daû Mg 2 und Citrat die Lo Èslichkeit erho Èhen, wogegen Harnstoff und Creatinin keine signi®kante Auswirkung haben.

show abstract

Section: Commentioning

confidence: 79%

Solubility of the Three Calcium Oxalate Hydrates in Sodium Chloride Solutionsand Urine-Like Liquors

Streit

Tran‐Ho

Königsberger

1998

Monatshefte fuer Chemie

View full text Add to dashboard Cite

show abstract

“…All the papers have been scrutinised in the NEA organics review [7]. For the final data analysis only studies carried out in NaCl and KCl media with proper characterization of the solids in equilibrium with the solutions have been considered [8][9][10][11][12][13][14][15]. In all the above cases analytical equilibrium concentration data of dissolved calcium, oxalate, NaCl or KCl have been reported, and the aqueous speciation was recalculated in the NEA organics review [7] as follows.…”

Section: Calcium Oxalate Solubilitymentioning

confidence: 99%

The OECD/NEA TDB review of selected organic ligands

Hummel¹,

Anderegg²,

Puigdomènech³

et al. 2005

Radiochimica Acta

121

View full text Add to dashboard Cite

Within the scope of the OECD Nuclear Energy Agency (NEA) Thermochemical Data Base Project (TDB) a comprehensive review of selected organic ligands has been carried out by the authors. The selected ligands are oxalate, citrate, ethylenediaminetetraacetate (edta) and α-isosaccharinate (isa), and the elements considered in the review are U, Np, Pu, Am, Tc, Ni, Se and Zr, as well as the necessary basic data concerning protonation of the ligands and interactions with the major competing elements Na, K, Mg and Ca. This review on organic ligands showed that the pragmatic ionic strength correction procedure, the Specific ion Interaction Theory (SIT), chosen as the default method for all NEA TDB reviews, can be applied successfully also to organic ligands. The SIT interaction parameters derived from ligand protonation data for different media, e.g. NaCl and KCl, pass the consistency test when applied to other systems evaluated in the organics review, e.g. solubility data. Hence, the thermodynamic constants selected in this NEA TDB organics review can be used with some confidence in real world applications, provided that SIT is used in the speciation calculations.

show abstract

“…The solubility of octocalcium phosphate drops by a factor of 3, if the urine pH is higher than 7 (17). Urea splitting bacteria for instance can shift the urine reaction into the alkaline region (18).…”

Section: We Think That In Immobilized Patientsmentioning

confidence: 99%