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PubMed1978

Inhibition of calcium absorption in ponies fed diets containing oxalic acid.

The effects of dietary oxalic acid on absorption, excretion, and retention of calcium was determined in Shetland ponies in 2 experiments. In each experiment, the results of feeding a control diet consisting of oats, molasses, and a complete pelleted horse ration were compared with those of feeding the control diet plus 1% oxalic acid. The diets contained 0.6% calcium in the 1st experiment and 0.45% calcium in the 2nd experiment. Oxalic acid increased the fecal excretion of calcium and decreased calcium absorption. The endogenous fecal excretion of calcium determined in the 1st experiment, using 47Ca, was not affected by dietary oxalic acid, indicating that the increase in fecal calcium was due to unabsorbed dietary calcium. Ponies fed 1% oxalic acid in diets containing 0.45% calcium were in negative calcium balance. The ponies did not conserve calcium by reducing the urinary calcium excretion if they were fed oxalic acid. Magnesium balance was measured in the 3 ponies in the 1st experiment. Urinary magnesium excretion increased and magnesium retention decreased in response to oxalic acid intake.

Administration, Oral↗
PubMed1995

[The effect of takusha and kagosou on calcium oxalate renal stones in rats].

We examined the inhibitory effect of the two Kampo medicines, takusha and kagosou on the formation of calcium oxalate renal stones induced by ethylene glycol (EG) and 1 alpha(OH)D3 (1 alpha-D3) in rats. Wistar strain rats were divided into 4 groups (A: normal control, B: stone, C: kagosou, D: takusya). There was no significant difference in urinary calcium excretion or oxalate excretion between the stone group and kampo medicine groups. The calcium content of the kidneys was significantly lower in the takusha group than in the other two groups (Stone group and kagosou group). Takusha was effective in preventing oxalate stone formation in rats. Kagosou, which had strong inhibitory effect on calcium oxalate crystal growth and aggregation in vitro as well as takusha, was not effective against in vivo calcium oxalate stone formation in rats. These findings suggest that takusha prevents the formation of calcium oxalate stone by inhibiting calcium oxalate crystal growth and aggregation.

Animals↗
PubMed1995

[Uro-oxalic renal lithiasis. Certain characteristics].

In a paper published in 1974, it was reported that uro-oxalic stones are found more often in subjects with group O than with group A blood types although the proportions of these two blood types are approximately equivalent in the French population. The present work confirms these data, the ratio of group O to group A renal lithiasis being approximately 3 to 1. In a paper published in 1987, uro-oxalic stones were found to occur preferentially on the left side: 84 on the left and 39 on the right. The present work confirms this notion since in 57 cases, stones were bilateral in 2 cases, on the left in 39 and on the right in 16. Extra corporeal shock wave lithotripsy was performed in 40 of the 57 cases and showed that uro-oxalic stones are most resistant to shock-waves than the other types of stones. They are about as hard as calcium oxalate monohydrate stones or harder in certain cases: A mean of 3,865 shock-waves were required in the 40 cases of the uro-oxalic lithiasis treated with the HM3 Dornier device, while the mean number of shock-waves required for all types of stones in general varies from 2,000 to 2,500. In 4 cases, 5,000 or 6,000 high power shock-waves (7,000 in one session and 9,500 in two sessions) had to be used to obtain a satisfactory result. The calcium oxalate part of these stones is almost always composed of calcium oxalate monohydrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Group Antigens↗
PubMed1994

[Uro-oxalic renal lithiasis. Special aspects].

In a paper published in 1974, it was reported that uro-oxalic stones are found more often in subjects with group O than with group A blood types although the proportions of these two blood types are approximately equivalent in the French population. The present work confirms these data, the ratio of group O to group A renal lithiasis being approximately 3 to 1. In a paper published in 1987, uro-oxalic stones were found to occur preferentially on the left side: 84 on the left and 39 on the right. The present work confirms this notion since in 57 cases, stones were bilateral in 2 cases, on the left in 39 and on the right in 16. Extra corporeal shock wave lithotripsy was performed in 40 of the 57 cases and showed that uro-oxalic stones are more resistant to shock-waves than the other types of stones. They are about as hard as calcium oxalate monohydrate stones or harder in certain cases: A mean of 3,865 shock-waves were required in the 40 cases of the uro-oxalic lithiasis treated with the HM3 Dornier device, while the mean number of shock-waves required for all types of stones in general varies from 2,000 to 2,500. In 4 cases, 5,000 or 6,000 high power shock-waves (7,000 in one session and 9,500 in two sessions) had to be used to obtain a satisfactory result. The calcium oxalate part of these stones is almost always composed of calcium oxalate monohydrate.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Group Antigens↗
PubMed1993

Absence of a transcellular oxalate transport mechanism in LLC-PK1 and MDCK cells cultured on porous supports.

Transepithelial oxalate transport across polarized monolayers of LLC-PK1 cells, grown on collagen-coated microporous membranes in Transwell culture chambers, was studied in double-label experiments using [14C]-oxalate together with [3H]-D-mannitol as an extracellular marker. The [14C]-labeled glucose analog alpha-methyl-glucoside (alpha-MG) was used as functional marker for active proximal tubular sugar transport. Cellular uptake of oxalate and alpha-MG at both the apical and basolateral plasma membrane was determined. When added to the upper compartment, alpha-MG was actively taken up at the apical membrane, directed through the cells to the basolateral membrane and transported to the lower compartment, indicating functional epithelial sugar transport by LLC-PK1 cells. In LLC-PK1 cells, the uptake of alpha-MG at the apical membrane was approximately 50 times higher than that at the basolateral membrane. In contrast to this active transport of sugar, LLC-PK1 cells did not demonstrate oxalate uptake either at the apical or basolateral plasma membrane. The apical-to-basolateral (A- > B) flux of oxalate in LLC-PK1 cells was identical to the basolateral-to-apical (B- > A) oxalate flux in these cells. Moreover these flux characteristics were similar to those found for D-mannitol, indicating paracellular movement for both compounds. From these data, it is concluded that, under the experimental conditions used, LLC-PK1 cells do not exhibit a specific transcellular transport system for oxalate.

Animals↗
PubMed1977

Oxalate absorption from intestinal segments of rats.

An animal experimental model was used to study oxalate absorption from the gut. It was found that the initial rate of [14C]oxalate absorption is rapid (6.5 per cent per min), and that after 5 min the rate of absorption decreases to about 0.6 per cent per min. Absorption of [14C]oxalate was greatest in the jejunum and least in the colon. On the basis of linear coefficients derived from the data, it is estimated that at least 8.6 per cent of a challenge dose of oxalate should be absorbed from the small bowel during normal transit. The high absorption rate, compared with the normal absorption of oxalate, in this model is most likely attributable to the oxalate's being completely dissolved in the gut. Magnesium and calcium in the test solution did not cause large changes in the rate or amount of oxalate transfer in this experimental model.

Animals↗
PubMed1996

Calcium oxalate crystals in human pathology. Molecular analysis with the laser Raman microprobe.

OBJECTIVE: Calcium oxalate crystals in pathologic specimens were examined by the laser Raman microprobe, a nondestructive spectroscopic technique. Although research focused on the identification of calcium oxalate deposits in tissue sections, kidney stones were also studied to determine the in situ structural specificity of the technique. DESIGN: Paraffin-embedded tissue specimens were cut into sections of 2 to 6 microns. The unstained sections were placed on metal (aluminum)-plated slides and excited with the 514.5-nm line of an argon-ion laser, which was focused to a 1-micron spot size using a high-resolution optical microscope. MAIN OUTCOME MEASURE: The laser Raman microprobe technique generates spectra that differentiate the monohydrate (CaC2O4.H2O, whewellite) and the dihydrate (CaC2O4.2H2O, weddellite) forms of calcium oxalate inclusions in tissue sections. RESULTS: Characteristic spectra were generated and provided unequivocal evidence for the identification of the dihydrate oxalate form of calcium oxalate crystals in cases of oxalosis of the myocardium and for the monohydrate oxalate structure in a case of oxalosis of the pituitary. Finally, the combined occurrence of both oxalate structures was confirmed in kidney stone specimens. CONCLUSION: The results obtained in this investigation demonstrate the efficacy of the laser Raman microprobe as a useful adjunct in diagnostic pathology.

Calcium Oxalate↗
PubMed1983

Urinary excretion of calcium, magnesium, oxalate and citrate in duodenal ulcer patients. Preliminary results before and up to five years after highly selective vagotomy.

The urinary excretion of calcium, oxalate, citrate and magnesium, and the relative saturation products in urine of either calcium oxalate or calcium phosphate, were determined in male duodenal ulcer (DU) patients preoperatively (n = 60), and 1 and 5 years following highly selective vagotomy (HSV), and in male healthy controls (n = 30). In DU before HSV citrate and magnesium were lowered, oxalate was in the low normal range and calcium was normal. The calcium oxalate product was lower than in controls, while the calcium phosphate product was unchanged. Within 5 years HSV normalized urinary citrate and oxalate, but not urinary magnesium, and the median urinary pH was lower than pre-operatively. There thus results a normal product for calcium oxalate, but a reduced one for calcium phosphate. It is suggested that: (1) unoperated DU patients have a urine composition similar to that exhibited in normocalciuric recurrent calcium urolithiasis; (2) this spectrum of urinary constituents may be changed by HSV.

Adult↗
PubMed1983

The determination of urinary oxalate by gas chromatography.

A new quantitative determination method for urinary oxalate by gas chromatography has been established. This method consists of concentration of urine to dryness followed by methylation of the oxalic acid with 7 per cent hydrochloric acid-methanol, subsequent extraction with chloroform and gas chromatographic analysis. The advantages of the technique are smaller sample sizes (only 5 ml.), rapidity (within 2 to 3 hours) and accuracy (99.14 plus or minus 1.34 per cent recovery). In addition, the treatment of the sample is simple and no specialized equipment is required. Therefore, this method is recommended to clinicians for routine determination of oxalic acid in urine. Urinary oxalate content was analyzed with this method in 62 male patients with calcium oxalate stones. Urinary oxalate concentration and excretion in 33 patients with recurrent stones were significantly higher than in the 22 controls using Welch's test.

Adult↗
PubMed2000

Dissolution of Nickel Ferrite in Aqueous Solutions Containing Oxalic Acid and Ferrous Salts.

The dissolution of nickel ferrite in oxalic acid and in ferrous oxalate-oxalic acid aqueous solution was studied. Nickel ferrite was synthesized by thermal decomposition of a mixed tartrate; the particles were shown to be coated with a thin ferric oxide layer. Dissolution takes place in two stages, the first one corresponding to the dissolution of the ferric oxide outer layer and the second one being the dissolution of Ni(1.06)Fe(1.96)O(4). The kinetics of dissolution during this first stage is typical of ferric oxides: in oxalic acid, both a ligand-assisted and a redox mechanism operates, whereas in the presence of ferrous ions, redox catalysis leads to a faster dissolution. The rate dependence on both oxalic acid and on ferrous ion is described by the Langmuir-Hinshelwood equation; the best fitting corresponds to K(1)(ads)=25.6 mol(-1) dm(-3) and k(1)(max)=9.17x10(-7) mol m(-2) s(-1) and K(2)(ads)=37.1x10(3) mol(-1) dm(-3) and k(2)(max)=62.3x10(-7) mol m(-2) s(-1), respectively. In the second stage, Langmuir-Hinshelwood kinetics also describes the dissolution of iron and nickel from nickel ferrite, with K(1)(ads)=20.8 mol(-1) dm(3) and K(2)(ads)=1.16x10(5) mol(-1) dm(3). For iron, k(1)(max)=1.02x10(-7) mol of Fe m(-2) s(-1) and k(2)(max)=2.38x10(-7) mol of Fe m(-2) s(-1); for nickel, the rate constants k(1)(max) and k(2)(max) are 2.4 and 1.79 times smaller, respectively. The factor 1.79 agrees nicely with the stoichiometric ratio, whereas the factor 2.4 implies the accumulation of some nickel in the residual particles. The rate of nickel dissolution in oxalic acid is higher than that in bunsenite by a factor of 8, whereas hematite is more reactive by a factor of 9 (in the absence of Fe(II)) and 27 (in the presence of Fe (II)). It may be concluded that oxalic acid operates to dissolve iron, and the ensuing disruption of the solid framework accelerates the release of nickel. Copyright 2000 Academic Press.

Journal Article↗
PubMed2004

Nuclear pore complex oxalate binding protein p62: expression in different kidney disorders.

BACKGROUND: Urolithiasis is a multifactorial process that starts with the formation of microcrystals in the urine and terminates as mature renal calculi. The oxalate binding protein plays a vital role in the transport of oxalate. The physiological significance of the presence of oxalate binding protein in the nuclear pore complex is not well understood. METHODS: The nuclear envelope was extracted from human cadaver kidneys. 14C oxalate was labeled, nuclear pore complex proteins were extracted and loaded onto Sephadex G-200, and further purified in DEAE-Sephadex A-50 column. The radioactive protein peak was pooled, concentrated and checked for purity in SDS-PAGE. The purified protein showed cross-reactivity with the monoclonal antibody (MAb 414) and was homogeneous. Urine samples of healthy individuals with no history of kidney disease served as control. Blood and urine samples were collected from kidney and autoimmune disorder patients and checked for the expression of p62 protein by ELISA. RESULTS: Extracted and purified nuclear pore complex oxalate binding protein had a molecular weight of 62 kDa. A threefold increase in oxalate excretion was observed in hyperoxaluric patients compared to control subjects. The protein expression was found to be higher in hyperoxaluric patients vs. controls, chronic renal failure (CRF) and acute renal failure (ARF), whereas decreased expression was observed in nephrotic syndrome (NS) patients. p62 autoantibodies was observed in hyperoxaluria (HO), systemic lupus erythematosus (SLE) and primary biliary cirrhosis (PBC), whereas it was absent in controls. CONCLUSION: Increased expression of p62 may be due to membrane damage induced by oxalate stress, and may be used as a diagnostic marker. This study also confirms the presence of p62 autoantibodies in HO patients.

Autoantibodies↗
PubMed2002

Oxalate-bridged complexes of dimolybdenum and ditungsten supported by pivalate ligands: ((t)BuCO(2))(3)M(2)(mu-O(2)CCO(2))M(2)(O(2)C(t)Bu)(3). Correlation of the solid-state, molecular, and electronic structures with Raman, resonance Raman, and electronic spectral data.

The compounds ((t)BuCO(2))(3)M(2)(mu-O(2)CCO(2))M(2)(O(2)C(t)Bu)(3) (M(4)OXA), where M = Mo or W, are shown by analysis of powder X-ray diffraction data to have extended lattice structures wherein oxygen atoms from the oxalate and pivalate ligands of one M(4)OXA molecule are linked to metal atoms of neighboring molecules. Raman, resonance Raman, electronic absorption (2-325 K in 2-MeTHF), and emission spectra are reported, together with corresponding spectra of the mu-O(2)(13)C(13)CO(2) isotopomers. To aid in the assignment, the Raman spectra of K(2)C(2)O(4).H(2)O and K(2)(13)C(2)O(4).H(2)O have also been recorded. The visible region of the electronic spectra is dominated by intense, fully allowed MLCT transitions, M(2) delta to oxalate pi*, which show pronounced thermochromism and extensive vibronic progressions associated with the oxalate ligand at low temperatures. With excitation into these charge-transfer bands, strong resonance enhancement is seen for Raman bands assigned to the oxalate nu(1)(a(g)) and, to a lesser extent, nu(2)(a(g)) modes. Electronic structure calculations for the model compounds (HCO(2))(3)M(2)(mu-O(2)CCO(2))M(2)(O(2)CH)(3), employing density functional theory (gradient corrected and time-dependent) with the Gaussian 98 and ADF 2000 packages, predict the planar oxalate D(2h) configuration to be favored, which maximizes M(2) delta to oxalate pi* back-bonding, and indicate low barriers (<8 kcal mol(-1)) to rotation about the oxalate C-C bonds.

Journal Article↗
PubMed1995

Tissue-Specific Expression of Germin-Like Oxalate Oxidase during Development and Fungal Infection of Barley Seedlings.

Oxalate oxidase activity was detected in situ during the development of barley seedlings. The presence of germin-like oxalate oxidase was confirmed by immunoblotting using an antibody directed against wheat germin produced in Escherichia coli, which is shown to cross-react with barley (Hordeum vulgare) oxalate oxidase and by enzymatic assay after electrophoresis of the protein extracts on polyacrylamide gels. In 3-d-old barley seedlings, oxalate oxidase is localized in the epidermal cells of the mature region of primary roots and in the coleorhiza. After 10 d of growth, the activity is detectable only in the coleorhiza. Moreover, we show that oxalate oxidase is induced in barley leaves during infection by the fungus Erysiphe graminis f. sp. hordei but not by wounding. Thus, oxalate oxidase is a new class of proteins that responds to pathogen attack. We propose that oxalate oxidase could have a role in plant defense through the production of H2O2.

Journal Article↗
PubMed1998

High aluminum resistance in buckwheat. I. Al-induced specific secretion of oxalic acid from root tips

High Al resistance in buckwheat (Fagopyrum esculentum Moench. cv Jianxi) has been suggested to be associated with both internal and external detoxification mechanisms. In this study the characteristics of the external detoxification mechanism, Al-induced secretion of oxalic acid, were investigated. Eleven days of P depletion failed to induce secretion of oxalic acid. Exposure to 50 &mgr;M LaCl3 also did not induce the secretion of oxalic acid, suggesting that this secretion is a specific response to Al stress. Secretion of oxalic acid was maintained for 8 h by a 3-h pulse treatment with 150 &mgr;M Al. A nondestructive method was developed to determine the site of the secretion along the root. Oxalic acid was found to be secreted in the region 0 to 10 mm from the root tip. Experiments using excised roots also showed that secretion was located on the root tip. Four kinds of anion-channel inhibitors showed different effects on Al-induced secretion of oxalic acid: 10 &mgr;M anthracene-9-carboxylic acid and 4, 4'-diisothiocyanatostilbene-2,2'-disulfonate had no effect, niflumic acid stimulated the secretion 4-fold, and phenylglyoxal inhibited the secretion by 50%. Root elongation in buckwheat was not inhibited by 25 &mgr;M Al or 10 &mgr;M phenylglyoxal alone but was inhibited by 40% in the presence of Al and phenylglyoxal, confirming that secretion of oxalic acid is associated with Al resistance.

Journal Article↗
PubMed1977

Adsorption of naturally occurring polymers onto calcium oxalate crystal surfaces.

The adsorption of proteins and mucopolysaccharides on calcium oxalate crystals was measured by solution depletion. Anionic protein adsorption was found to be sensitive to calcium ion concentration. Adsorption of fibrinogen was anomalously large in the presence of 0.01 M Ca2+. Adsorption of cationic protein (histone) was sensitive to oxalate ion concentration. A small alteration in adsorption of protein as a result of pH or temperature change was also observed. Plots of adsorption versus concentration were interpreted in terms of a Langmuir adsorption isotherm. The derived Langmuir adsorption parameters were then used to investigate the contribution of protein, by physical adsorpti, to the quantity of matrix in urinary stones. It was concluded that physical adsorption can account for the deposition of part but not all of the matrix in calcium oxalate stones. It was also concluded that physical adsorption of mucopolysaccharides by calcium oxalate crystals could explain the inhibition of growth and aggregation of calcium oxalate crystals seen with in vitro precipitation systems. Recalculation of published data indicates that adsorption of protein on dental enamel (calcium hydroxyapatite) results in approximately the same extent of surface coverage as adsorption on calcium oxalate crystals, but protein has a much lower affinity for dental enamel than for calcium oxalate crystals.

Adsorption↗
PubMed1987

Oxalic acid biosynthesis and oxalacetate acetylhydrolase activity in Streptomyces cattleya.

In addition to producing the antibiotic thienamycin, Streptomyces cattleya accumulates large amounts of oxalic acid during the course of a fermentation. Washed cell suspensions were utilized to determine the specific incorporation of carbon-14 into oxalate from a number of labeled organic and amino acids. L-[U-14C]aspartate proved to be the best precursor, whereas only a small percentage of label from [1,5-14C]citrate was found in oxalate. Cell-free extracts catalyzed the formation of [14C]oxalate and [14C]acetate from L-[U-14C]aspartate. When L-[4-14C]aspartate was the substrate only [14C]acetate was formed. The cell-free extracts were found to contain oxalacetate acetylhydrolase (EC 3.7.1.1), the enzyme that catalyzes the hydrolysis of oxalacetate to oxalate and acetate. The enzyme is constitutive and is analogous to enzymes in fungi that produce oxalate from oxalacetate. Properties of the crude enzyme were examined.

Aspartic Acid↗
PubMed1983

Oxalate-stimulation of ATP-dependent Ca-uptake is diminished during smooth muscle subcellular fractionation.

The ATP-dependent azide-insensitive Ca-uptake by the postnuclear supernatant from rat myometrium is stimulated more by 5 mM oxalate than by 25 mM phosphate. During subcellular fractionation, however, the percent recovery of the oxalate stimulated Ca-uptake diminishes more rapidly than that of the Ca-uptake without any added oxalate or phosphate. The percent recovery of the phosphate stimulated Ca-uptake also diminishes but not to as low levels as that of the oxalate stimulated Ca-uptake. The net result is higher stimulation of this uptake by 25 mM phosphate than by 5 mM oxalate in the various sucrose density gradient fractions. This discrepancy in percent recoveries presents a major concern about the use of oxalate or phosphate stimulated Ca-uptake as a marker for smooth muscle membranes.

Adenosine Triphosphate↗
PubMed1983

Urinary oxalate excretion, as determined by isotope dilution and indirect colorimetry.

A simple and reliable method for the determination of urinary oxalate excretion is described. Urinary oxalate is precipitated with calcium chloride, and the oxalate content of the precipitate is measured by an indirect colorimetric method developed by Neas and Guyon in 1972 [1]. For single urine samples, a correction is made for the incompleteness of the precipitation of calcium oxalate by isotope dilution. The range of normal values (5% limits) determined in 52 normal subjects was 0.121-0.325 mmol . 24 h-1 . m-2 for a 1-day collection period and 0.145-0.301 mmol . 24 h-1 . m-2 for a 3-day collection period. The within-assay CV of a control urine with a low oxalate concentration was 9% (n = 7) and the between-assay CV for the same control urine was 12% (n = 6). When the values obtained for oxalate excretion were normalized to body surface area, there was no significant difference between males and females; the main source of variation was the intra-individual variation.

Body Surface Area↗