[Injuries caused by oxalic acid and potassium acid oxalate in reactions on the skin].
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The influence of a long-term application of 4 different hormonal contraceptives on the excretion of various constituents of the urine was examined. A reverse effect after stoppage of the medication is to be established in none of the other parameters with the exception of calcium.
Urinary excretion of 4-pyridoxic acid and oxalic acid was investigated in 75 patients with urinary calculi and in 50 normal subjects on regular diet. Mean excretion of 4-pyridoxic acid was 0.85 and 0.90 mg per day, respectively, and mean excretion of oxalic acid was 27.5 and 28.0 mg per day, respectively. Statistically there was no difference between the two groups in 4-pyridoxic acid excretion or in oxalic acid excretion. There was a weak positive correlation between the urinary excretion of 4-pyridoxic acid and oxalic acid. Patients who were on ascorbic acid supplementation during the urine collection period excreted increased amounts of oxalic acid. It was concluded from this investigation that most patients with urinary calculi had 4-pyridoxic acid excretion and oxalic acid excretion within normal limits. Low 4-pyridoxic acid values were not combined with high excretion values of oxalic acid, and the nutritional state of vitamin B6 in patients with urinary calculi was assumed to be satisfactory in order to control the endogenous oxalic acid production. The significance of high excretion values of 4-pyridoxic acid and oxalic acid is discussed.
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Oxalic acid determinations are made using two modes of electrochemical detection, namely, classical d.c. and differential pulse, after separation by ion-pair, ion exchange high performance liquid chromatography. Peak height ratio plots are constructed and compared for uric acid and oxalic acid mixtures using both electrochemical detection modes. The enhanced selectivity realized by use of the differential pulse electrochemical detection mode is demonstrated.
Studies on effects of fiber, phytic acid, and oxalic acid on mineral bioavailability are reviewed. It is difficult to separate the effects of fiber and phytic acid when cereal products are fed, because they occur together in these foods. However, even the combination of fiber and phytic acid does not appear to affect mineral balances unless unrefined cereal intakes are high and mineral intakes are low. Also, the body may be able to adjust to the decreased availability by increased absorption of the available mineral. Oxalic acid may result in decreases in mineral bioavailability if consumed with a high fiber diet, but the decrease may also be transient.
l-Ascorbic acid-1-(14)C and its oxidation product, dehydro-l-ascorbic acid, produced labeled oxalic acid in oxalate-accumulating plants such as spinach seedlings (Spinacia oleracea) and the detached leaves of woodsorrel (Oxalis stricta and O. oregana), shamrock (Oxalis adenopylla), and begonia (Begonia evansiana). In O. oregana, conversion occurred equally well in the presence or absence of light. This relationship between l-ascorbic acid metabolism and oxalic acid formation must be given careful consideration in attempts to explain oxalic accumulation in plants.
D-glycero-Pent-2-enono-1,4-lactone (trivial name: D-erythroascorbic acid) occurs in the phytopathogen, Sclerotinia sclerotiorum (Lib.) de Bary, where it has a potential role as precursor of oxalic acid. On Glc/yeast/malt medium, S. sclerotiorum produces only nominal amounts of D-erythroascorbic acid but even partial replacement of Glc by D-Ara increases production of erythroascorbic acid and oxalic acid. Use of D-[1-14C]-, -[3-14C]-, or -[6-14C]Glc and D-[5-3H]-, -[2-14C,5-3H]-, or -[UL-14C]Ara provide additional information on erythroascorbic acid biosynthesis and cleavage. The latter process resembles that obtained by peroxygenation of erythroascorbic acid in alkaline solution. An unknown erythroascorbic acid-like compound also occurs in both Glc- and Ara-based cultures.
L-Ascorbic acid (AsA) and its metabolic precursors give rise to oxalic acid (OxA) found in calcium oxalate crystals in specialized crystal idioblast cells in plants; however, it is not known if AsA and OxA are synthesized within the crystal idioblast cell or transported in from surrounding mesophyll cells. Isolated developing crystal idioblasts from Pistia stratiotes were used to study the pathway of OxA biosynthesis and to determine if idioblasts contain the entire path and are essentially independent in OxA synthesis. Idioblasts were supplied with various (14)C-labeled compounds and examined by micro-autoradiography for incorporation of (14)C into calcium oxalate crystals. [(14)C]OxA gave heavy labeling of crystals, indicating the isolated idioblasts are functional in crystal formation. Incubation with [1-(14)C]AsA also gave heavy labeling of crystals, whereas [6-(14)C]AsA gave no labeling. Labeled precursors of AsA (L-[1-(14)C]galactose; D-[1-(14)C]mannose) also resulted in crystal labeling, as did the ascorbic acid analog, D-[1-(14)C]erythorbic acid. Intensity of labeling of isolated idioblasts followed the pattern OxA > AsA (erythorbic acid) > L-galactose > D-mannose. Our results demonstrate that P. stratiotes crystal idioblasts synthesize the OxA used for crystal formation, the OxA is derived from the number 1 and 2 carbons of AsA, and the proposed pathway of ascorbic acid synthesis via D-mannose and L-galactose is operational in individual P. stratiotes crystal idioblasts. These results are discussed with respect to fine control of calcium oxalate precipitation and the concept of crystal idioblasts as independent physiological compartments.
It is reported on individual methods for the estimation of the oxalic acid in body fluids, particularly in the urine. The case in question is a survey of the oxalate estimation methods, which, however, has no pretensions to completeness. The at present most actualestimation methods are brought somewhat more in detail. The data are not sufficient for the laboratorytechnical performance of the individual methods, this would transgress the possibilities of the work. However, the original papers are cited which contain all the necessary details. Some technical difficulties and disturbances in the individual estimation methods are also entered. Despite excellent work of several teams the problems of standardization, of the absolutely reliable reference methoda as well as of an objective consideration of advantages and disadvantages of individual, often subjectively judged methods is not yet solved. Comparing these methods, one gets the impression that several reliable methods of the same value are established. It seems that this estimation method brings the greatest progress which will reliably establish so small quantities of oxalate as they are in the blood or in the liquor. By this also the oxalate clearance and the renal oxalate treatment becomes more exactly establishable than up to now.
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Rumen microbial degradation is an important route for detoxification of secondary plant compounds encountered in the diets of free-grazing ruminants. Exposure to diets containing particular secondary plant compounds can lead to increased rates of secondary compound degradation in the rumen. An experiment was conducted to determine whether rumen adaptation to oxalic acid would influence the diet selection of goats offered choices between plant species differing in their oxalic acid content. Twelve adult female goats were divided into two groups of six animals each. One group received a daily oral dose, in gelatin capsules, of 0.6 mmol oxalic acid/kg live weight per d throughout the experiment while the other group received placebos consisting of empty gelatin capsules. After an adaptation period of 8 d, the animals were allowed to graze a mixture of spinach (rich in oxalic acid) and cabbage (low in oxalic acid) for 7 h/d on two consecutive days per week during four consecutive 1-week periods. Intervening days were spent on grass pasture. Diet composition and intake were measured using cuticular wax n-alkanes as internal markers. Results showed that adapted goats included a higher proportion of spinach in their diet (P < 0.05) although absolute intakes of spinach were the same for the two groups. Goats in the oxalic-acid-adapted group consumed less cabbage than control animals (P < 0.05) suggesting that adaptation to oxalic acid at the rumen level may have interfered with detoxification of cabbage-derived secondary plant compounds. Voluntary intake increased progressively through the four experimental periods (P < 0.001) with a tendency for higher intakes among control than among adapted animals (P < 0.1). The experiment demonstrates how differences in the rate of degradation of secondary plant compounds may influence diet selection in ruminants.
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A group of normal children with a free diet was studied. Their first morning urine (n = 176) and their 24-hour-urine (n = 64) was collected, valuing the calciuria, magnesiuria, uricosuria and oxaluria, establishing their relationship with a dietetic survey. Ca/Cr rate value was 0.13 +/- 0.7 mg/mg in the morning urine, and 0.12 +/- 0.06 mg/mg in the 24-hour-urine. Calciuria (mg/kg/day) was 2.46 +/- 1.45, higher to that noticed by other authors. Prevalence of hypercalciuria was 7.8%. We haven't noticed any correlation between the calciuria (mg/kg/day) and the consumption of proteins and carbohydrates. A positive correlation was found between Ca/Cr and Na/Cr rate, together with high natriuria (3.87 +/- 1.35 mEq/kg/day); these findings could justify the elevated calciuria in the children studied. Mean values of magnesium and uric acid were 0.04 +/- 0.02 and 0.30 +/- 0.08 mg/100 ml FG, respectively and the oxaluria was 34.51 +/- 16.35 mg/day/1.73 m2.
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In 43 healthy reference persons and 54 patients with relapsing calcium oxalate nephrolithiasis the absorption of oxalic acid was measured by means of 14C-oxalic acid. In patients with oxalate calculi the absorption of oxalic acid is totally increased and also in such ones with Whewellite-calculi. It is decreased in carriers of Weddelite calculi. The increase of the absorption of oxalic acid in patients with mixed calculi is not significant.
Plasma oxalic acid concentrations were measured in 13 chronic haemodialysis patients. The mean plasma oxalic acid concentration was 128.0 +/- 48.6 mumol/l, being approximately 8 times higher than the plasma concentration of 14 volunteers (mean = 16.8 +/- 5.2 mumol/l). Ultrafiltrates obtained in vivo from these patients showed a mean oxalic acid concentration of 138.2 +/- 56.5 mumol/l. Since in vivo ultrafiltrates are free of erythrocytes and plasma enzymes, an in vitro synthesis of oxalic acid from precursors by erythrocytes and plasma enzymes can be excluded. As the oxalic acid concentration of plasma corresponded to that of in vivo ultrafiltrates, it is concluded that any in vitro formation of oxalic acid in haemodialysis patients must be negligibly small, and is irrelevant for the measurement of plasma oxalic acid levels in patients receiving regular haemodialysis.