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Sample records for experimental calcium oxalate

  1. The Interaction between Enterobacteriaceae and Calcium Oxalate Deposits

    PubMed Central

    Barr-Beare, Evan; Saxena, Vijay; Hilt, Evann E.; Thomas-White, Krystal; Schober, Megan; Li, Birong; Becknell, Brian; Hains, David S.; Wolfe, Alan J.; Schwaderer, Andrew L.

    2015-01-01

    Background The role of calcium oxalate crystals and deposits in UTI pathogenesis has not been established. The objectives of this study were to identify bacteria present in pediatric urolithiasis and, using in vitro and in vivo models, to determine the relevance of calcium oxalate deposits during experimental pyelonephritis. Methods Pediatric kidney stones and urine were collected and both cultured and sequenced for bacteria. Bacterial adhesion to calcium oxalate was compared. Murine kidney calcium oxalate deposits were induced by intraperitoneal glyoxalate injection and kidneys were transurethrally inoculated with uropathogenic Escherichia coli to induce pyelonephritis Results E. coli of the family Enterobacteriaceae was identified in patients by calcium oxalate stone culture. Additionally Enterobacteriaceae DNA was sequenced from multiple calcium oxalate kidney stones. E. coli selectively aggregated on and around calcium oxalate monohydrate crystals. Mice inoculated with glyoxalate and uropathogenic E. coli had higher bacterial burdens, increased kidney calcium oxalate deposits and an increased kidney innate immune response compared to mice with only calcium oxalate deposits or only pyelonephritis. Conclusions In a murine model, the presence of calcium oxalate deposits increases pyelonephritis risk, likely due to preferential aggregation of bacteria on and around calcium oxalate crystals. When both calcium oxalate deposits and uropathogenic bacteria were present, calcium oxalate deposit number increased along with renal gene transcription of inner stone core matrix proteins increased. Therefore renal calcium oxalate deposits may be a modifiable risk factor for infections of the kidney and urinary tract. Furthermore, bacteria may be present in calcium oxalate deposits and potentially contribute to calcium oxalate renal disease. PMID:26448465

  2. Medical therapy, calcium oxalate urolithiasis

    NASA Technical Reports Server (NTRS)

    Ruml, L. A.; Pearle, M. S.; Pak, C. Y.

    1997-01-01

    The development of diagnostic protocols that identify specific risk factors for calcium oxalate nephrolithiasis has led to the formulation of directed medical regimens that are aimed at correcting the underlying metabolic disturbances. Initiation of these treatment programs has reduced markedly the rate of stone formation in the majority of patients who form stones. This article discusses the rationale that underlies the choice of medical therapy for the various pathophysiologic causes of calcium oxalate nephrolithiasis and the appropriate use of available medications.

  3. Oxalate: Effect on calcium absorbability

    SciTech Connect

    Heaney, R.P.; Weaver, C.M. )

    1989-10-01

    Absorption of calcium from intrinsically labeled Ca oxalate was measured in 18 normal women and compared with absorption of Ca from milk in these same subjects, both when the test substances were ingested in separate meals and when ingested together. Fractional Ca absorption from oxalate averaged 0.100 +/- 0.043 when ingested alone and 0.140 +/- 0.063 when ingested together with milk. Absorption was, as expected, substantially lower than absorption from milk (0.358 +/- 0.113). Nevertheless Ca oxalate absorbability in these women was higher than we had previously found for spinach Ca. When milk and Ca oxalate were ingested together, there was no interference of oxalate in milk Ca absorption and no evidence of tracer exchange between the two labeled Ca species.

  4. Lowering urinary oxalate excretion to decrease calcium oxalate stone disease

    PubMed Central

    Knight, John; Assimos, Dean G.

    2016-01-01

    Dietary modifications should be considered as a first line approach in the treatment of idiopathic calcium oxalate nephrolithiasis. The amounts of oxalate and calcium consumed in the diet are significant factors in the development of the disease due to their impact on urinary oxalate excretion. There are a number of strategies that can be employed to reduce oxalate excretion. The consumption of oxalate-rich foods should be avoided and calcium intake adjusted to 1000–1200 mg/day. To encourage compliance it should be emphasized to patients that they be vigilant with this diet as a deviation in any meal or snack could potentially result in significant stone growth. The evidence underlying these two modifications is outlined and other strategies to reduce urinary oxalate excretion are reviewed. PMID:26614109

  5. Oxalic acid decreases calcium absorption in rats

    SciTech Connect

    Weaver, C.M.; Martin, B.R.; Ebner, J.S.; Krueger, C.A.

    1987-11-01

    Calcium absorption from salts and foods intrinsically labeled with /sup 45/Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO/sub 3/ and CaCl/sub 2/ than from CaC/sub 2/O/sub 4/ (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach.

  6. Oxalic acid decreases calcium absorption in rats.

    PubMed

    Weaver, C M; Martin, B R; Ebner, J S; Krueger, C A

    1987-11-01

    Calcium absorption from salts and foods intrinsically labeled with 45Ca was determined in the rat model. Calcium bioavailability was nearly 10 times greater for low oxalate kale, CaCO3 and CaCl2 than from CaC2O4 (calcium oxalate) and spinach (high in oxalates). Extrinsic and intrinsic labeling techniques gave a similar assessment of calcium bioavailability from kale but not from spinach.

  7. Engineering calcium oxalate crystal formation in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many plants accumulate crystals of calcium oxalate. Just how these crystals form remains unknown. To gain insight into the mechanisms regulating calcium oxalate crystal formation, a crystal engineering approach was initiated utilizing the non-crystal accumulating plant, Arabidopsis. The success of t...

  8. Patterns of calcium oxalate monohydrate crystallization in complex biological systems

    NASA Astrophysics Data System (ADS)

    Golovanova, O. A.; Korol’kov, V. V.; Kuimova, M. V.

    2017-01-01

    The paper presents the features of calcium oxalate crystallization in the presence of additives revealed through experimental modeling. The patterns of phase formation are shown for the Ca2+ – C2O4 2– – H2O and Ca2+ – C2O4 2– – PO4 3– – H2O systems with the components and pH of the saline varying over a wide concentrations range. The effect of additives on crystallization of calcium oxalate monohydrate was investigated. It was found that the ionic strength and magnesium ions are inhibitors, and calcium oxalate and hydroxyapatite crystals are catalysts of calcium oxalate monohydrate crystallization. The basic calcium phosphate (apatite) was found to be most thermodynamically stable, which indicates its special role in kidney stone formation since it is found in virtually all stones.

  9. Characterization of Medicago truncatula reduced calcium oxalate crystal mutant alleles

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium oxalate crystal formation is common in plants. Formation of these crystals has been shown to function in plant defense, calcium regulation, and aluminum tolerance. Although calcium oxalate is common and plays important roles in plant development, our understanding of how these crystals form ...

  10. Contribution of calcium oxalate to soil-exchangeable calcium

    USGS Publications Warehouse

    Dauer, Jenny M.; Perakis, Steven S.

    2013-01-01

    Acid deposition and repeated biomass harvest have decreased soil calcium (Ca) availability in many temperate forests worldwide, yet existing methods for assessing available soil Ca do not fully characterize soil Ca forms. To account for discrepancies in ecosystem Ca budgets, it has been hypothesized that the highly insoluble biomineral Ca oxalate might represent an additional soil Ca pool that is not detected in standard measures of soil-exchangeable Ca. We asked whether several standard method extractants for soil-exchangeable Ca could also access Ca held in Ca oxalate crystals using spike recovery tests in both pure solutions and soil extractions. In solutions of the extractants ammonium chloride, ammonium acetate, and barium chloride, we observed 2% to 104% dissolution of Ca oxalate crystals, with dissolution increasing with both solution molarity and ionic potential of cation extractant. In spike recovery tests using a low-Ca soil, we estimate that 1 M ammonium acetate extraction dissolved sufficient Ca oxalate to contribute an additional 52% to standard measurements of soil-exchangeable Ca. However, in a high-Ca soil, the amount of Ca oxalate spike that would dissolve in 1 M ammonium acetate extraction was difficult to detect against the large pool of exchangeable Ca. We conclude that Ca oxalate can contribute substantially to standard estimates of soil-exchangeable Ca in acid forest soils with low soil-exchangeable Ca. Consequently, measures of exchangeable Ca are unlikely to fully resolve discrepancies in ecosystem Ca mass balance unless the contribution of Ca oxalate to exchangeable Ca is also assessed.

  11. Calcium Oxalate Accumulation in Malpighian Tubules of Silkworm (Bombyx mori)

    NASA Astrophysics Data System (ADS)

    Wyman, Aaron J.; Webb, Mary Alice

    2007-04-01

    Silkworm provides an ideal model system for study of calcium oxalate crystallization in kidney-like organs, called Malpighian tubules. During their growth and development, silkworm larvae accumulate massive amounts of calcium oxalate crystals in their Malpighian tubules with no apparent harm to the organism. This manuscript reports studies of crystal structure in the tubules along with analyses identifying molecular constituents of tubule exudate.

  12. Experimental oxalate urolith formation in rats.

    PubMed

    McIntosh, G H; Belling, G B; Bulman, F H

    1979-06-01

    Urinary calculi composed of calcium oxalate were produced in male hooded Wistar rats fed a vitamin B6 deficient diet over 16 weeks. This basic diet was modified by doubling the phosphate content or loading with vitamin C or D3 in three treatment groups. The number of rats developing oxalate stones was not altered by the addition of vitamin D3 or phosphate, but there was a significant increase in total weight of stone formed and histological evidence of extensive renal damage in rats on the high vitamin D3 diet. The addition of vitamin C to the vitamin B6 deficient rats resulted in a reduction in the number of rats with uroliths and a fall in urinary oxalate excretion, while similarly loaded vitamin B6 supplemented controls were free of oxalate calculi. It is concluded that the oxalate urolithiasis induced by vitamin B6 deficiency was exacerbated by added vitamin D3 and reduced by vitamin C.

  13. Addition of calcium compounds to reduce soluble oxalate in a high oxalate food system.

    PubMed

    Bong, Wen-Chun; Vanhanen, Leo P; Savage, Geoffrey P

    2017-04-15

    Spinach (Spinacia oleracea L.) is often used as a base vegetable to make green juices that are promoted as healthy dietary alternatives. Spinach is known to contain significant amounts of oxalates, which are toxic and, if consumed regularly, can lead to the development of kidney stones. This research investigates adding 50-500mg increments of calcium carbonate, calcium chloride, calcium citrate and calcium sulphate to 100g of raw homogenates of spinach to determine whether calcium would combine with the soluble oxalate present in the spinach. Calcium chloride was the most effective additive while calcium carbonate was the least effective. The formation of insoluble oxalate after incubation at 25°C for 30min is a simple practical step that can be incorporated into the juicing process. This would make the juice considerably safer to consume on a regular basis.

  14. Effect of A. lanata leaf extract and Vediuppu chunnam on the urinary risk factors of calcium oxalate urolithiasis during experimental hyperoxaluria.

    PubMed

    Selvam, R; Kalaiselvi, P; Govindaraj, A; Bala Murugan, V; Sathish Kumar, A S

    2001-01-01

    Urolithiasis is one of the third most common afflictions found in humans. The efficacy of the two Siddha drugs, Aerva lanata and Vediuppu chunnam as antilithic agents using a urolithic rat model were tested in this study. Hyperoxaluria was induced in rats using 0.75% ethylene glycol in drinking water. Aerva lanata(3.0 mg kg(-1)body weight) and Vediuppu chunnam (3.5 mg kg(-1)body weight) were given orally for 28 days. Urinary risk factors of urolithiasis were monitored at the end of 7th, 14th, 21st and 28th days. Urinary volume was increased in hyperoxaluric as well as drug-treated rats. Increased urinary excretion of calcium, oxalate, uric acid, phosphorus and protein in hyperoxaluric rats was brought down significantly by the administration of A. lanata or Vediuppu chunnam. Decreased magnesium excretion in hyperoxaluric rats was normalized by drug treatment. The drug increases the urine volume, thereby reducing the solubility product with respect to calcium oxalate and other crystallizing salts such as uric acid, which may induce epitaxial deposition of calcium oxalate. Drug alone treated rats did not show any adverse effects. Combination therapy was found to be more effective and this indigenous medicine can be used successfully as an antilithic agent.

  15. Influence of calcium oxalate crystal accumulation on the calcium content of seeds from Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crystals of calcium oxalate often form in cells adjacent to the vascular bundles in the tissues along the xylem stream. This spatial crystal pattern suggests a role for calcium oxalate formation in regulating calcium transport and partitioning to edible organs such as seeds. To investigate this pote...

  16. Calcium oxalate content affects the nutritional availability of calcium from Medicago truncatula leaves

    Technology Transfer Automated Retrieval System (TEKTRAN)

    It is known that oxalate, present in edible plants, can bind calcium in a crystalline form that reduces the availability of the bound calcium for nutritional absorption by humans. It is unknown, however, the degree to which the calcium oxalate content of a plant can be genetically altered and how mu...

  17. Calcium Oxalate Induces Renal Injury through Calcium-Sensing Receptor

    PubMed Central

    Li, Xiaoran; Ma, Junhai; Shi, Wei; Su, Yu; Fu, Xu; Yang, Yanlin; Lu, Jianzhong

    2016-01-01

    Objective. To investigate whether calcium-sensing receptor (CaSR) plays a role in calcium-oxalate-induced renal injury. Materials and Methods. HK-2 cells and rats were treated with calcium oxalate (CaOx) crystals with or without pretreatment with the CaSR-specific agonist gadolinium chloride (GdCl3) or the CaSR-specific antagonist NPS2390. Changes in oxidative stress (OS) in HK-2 cells and rat kidneys were assessed. In addition, CaSR, extracellular signal-regulated protein kinase (ERK), c-Jun N-terminal protein kinase (JNK), and p38 expression was determined. Further, crystal adhesion assay was performed in vitro, and the serum urea and creatinine levels and crystal deposition in the kidneys were also examined. Results. CaOx increased CaSR, ERK, JNK, and p38 protein expression and OS in vitro and in vivo. These deleterious changes were further enhanced upon pretreatment with the CaSR agonist GdCl3 but were attenuated by the specific CaSR inhibitor NPS2390 compared with CaOx treatment alone. Pretreatment with GdCl3 further increased in vitro and in vivo crystal adhesion and renal hypofunction. In contrast, pretreatment with NPS2390 decreased in vitro and in vivo crystal adhesion and renal hypofunction. Conclusions. CaOx-induced renal injury is related to CaSR-mediated OS and increased mitogen-activated protein kinase (MAPK) signaling, which subsequently leads to CaOx crystal adhesion. PMID:27965733

  18. Modulation of polyepoxysuccinic acid on crystallization of calcium oxalate

    SciTech Connect

    Zhang, Yanqing; Tang, Yongming; Xu, Jinqiu; Zhang, Dongqin; Lu, Gang; Jing, Wenheng

    2015-11-15

    The influence of polyepoxysuccinic acid (PESA) on the phase composition and crystal morphology of calcium oxalate was investigated in this paper. It was found that the presence of PESA inhibited the growth of the monoclinic calcium oxalate monohydrate (COM) crystal and promoted the nucleation of the tetragonal calcium oxalate dihydrate (COD). In addition, with the increase in PESA concentration, the aggregation of COD crystals was reduced but the particle size was increased. Under the conditions of low calcium-to-oxalate ratio and high CaOx concentration, PESA could not effectively stabilize the formation of COD. Based on molecular dynamic simulations, the adsorption of PESA on CaOx crystal faces was confirmed. - Graphical abstract: Introduction of PESA into crystallization solutions promotes the formation of calcium oxalate dehydrate and modifies the morphology of crystals. - Highlights: • PESA induces the formation of COD at low supersaturation. • Establishment of Ca-rich surface augments the adsorption of PESA. • At Ca/Ox=0.5 PESA cannot induce the formation of COD compared with Ca/Ox=2. • Interaction of PESA with COM faces is stronger than that with COD faces.

  19. Calcium extraction from brine water and seawater using oxalic acid

    NASA Astrophysics Data System (ADS)

    Natasha, Nadia Chrisayu; Lalasari, Latifa Hanum

    2017-01-01

    Calcium can be extracted not only from rocks but also from natural liquor such as seawater and brine water. In order to extract the calcium from seawater and brine water, oxalic acid was used in this research. Effect of variations of the volume of the oxalic acid at a constant concentration in seawater and brine water to produce calcium was investigated. The concentration of oxalic acid was 100 g/l and the variations of its volume were 2 ml, 4 ml, 6 ml, 8 ml, 10 ml, 20 ml, 30 ml, 40 ml, and 50 ml. The used seawater and brine water were firstly evaporated from 100 ml into 50 ml and then the oxalic acid was added into them with mixing to produce the calcium precipitates. The precipitates were analyzed by X-ray diffraction (XRD) and scanning electron microscope (SEM) and the filtrates were analyzed by inductively coupled plasma-optical emission spectrometry (ICP-OES). The SEM analysis showed that the precipitates from brine water were consisted of only calcium compound while from seawater sodium one was also found along with calcium compound. The XRD analysis showed that the calcium was present in the form of calcium oxalate for both seawater and brine water. The ICP-OES analysis of the filtrate from seawater precipitation showed that the its calcium content was decreased from 826.20 ppm to 0.04 ppm while from brine water, it decreased from 170.06 ppm to 1.96 ppm. These results showed that both seawater and brine water have the potential to be a raw material for calcium production.

  20. Calcium oxalate contribution to calcium cycling in forests of contrasting nutrient status

    USGS Publications Warehouse

    Dauer, Jenny M.; Perakis, Steven S.

    2014-01-01

    Calcium oxalate (Ca oxalate) is an insoluble biomineral that forms in plants and fungi, and occurs in soils across many types of ecosystems. Assessing how Ca oxalate may shape ecosystem Ca cycling requires information on the distribution of Ca oxalate among plant biomass, detritus, and mineral soil, and how it varies with ecosystem Ca status. We compared two Douglas-fir forests of contrasting ecosystem Ca availability, and found that Ca oxalate was partitioned similarly among plant biomass, detritus and mineral soil major ecosystem compartments at both sites, and total pools of Ca oxalate were greater in the high-Ca forest. However, the proportional importance of Ca oxalate was greater in the low-Ca than high-Ca forest (18% versus 4% of actively cycling ecosystem Ca, respectively). And calcium oxalate in mineral soil, which is of particular interest as a potential long-term Ca reservoir, was a larger portion of total available Ca (exchangeable Ca plus Ca oxalate Ca) in the low-Ca site than the high-Ca site (9% versus 1% of available soil Ca, respectively). Calcium oxalate was the dominant form of Ca returned from plants to soil as leaf litterfall at the high-Ca site, yet calcium oxalate disappeared rapidly from decomposing litter (0.28 yr−1 or faster) at both sites. We conclude that accumulation of Ca oxalate in forest ecosystems appears most closely related to overall Ca supply for live biomass pools, and that the accumulation of Ca oxalate in forest floor and mineral soil is limited by rapid microbial degradation of putatively unavailable Ca oxalate.

  1. The influence of scale inhibitors on calcium oxalate

    SciTech Connect

    Gill, J.S.

    1999-11-01

    Precipitation of calcium oxalate is a common occurrence in mammalian urinary tract deposits and in various industrial processes such as paper making, brewery fermentation, sugar evaporation, and tannin concentration. Between pH 3.5 to 4.5 the driving force for calcium oxalate precipitation increases almost by three fold. It is a complicated process to predict both the nature of a deposit and at which stage of a multi-effect evaporator a particular mineral will deposit, as this depends on temperature, pH, total solids, and kinetics of mineralization. It is quite a challenge to inhibit calcium oxalate precipitation in the pH range of 4--6. Al{sup 3+} ions provide excellent threshold inhibition in this pH range and can be used to augment traditional inhibitors such as polyphosphates and polycarboxylates.

  2. Microelectrophoretic study of calcium oxalate monohydrate in macromolecular solutions

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Onoda, G. Y., Jr.; Finlayson, B.

    1987-01-01

    Electrophoretic mobilities were measured for calcium oxalate monohydrate (COM) in solutions containing macromolecules. Two mucopolysaccharides (sodium heparin and chondroitin sulfate) and two proteins (positively charged lysozyme and negatively charged bovine serum albumin) were studied as adsorbates. The effects of pH, calcium oxalate surface charge (varied by calcium or oxalate ion activity), and citrate concentration were investigated. All four macromolecules showed evidence for adsorption. The macromolecule concentrations needed for reversing the surface charge indicated that the mucopolysaccharides have greater affinity for the COM surface than the proteins. Citrate ions at high concentrations appear to compete effectively with the negative protein for surface sites but show no evidence for competing with the positively charged protein.

  3. Influence of calcium oxalate crystal accumulation on the calcium content of seeds from Medicago truncatula.

    PubMed

    Nakata, Paul A

    2012-04-01

    Crystals of calcium oxalate often form in cells adjacent to the vascular bundles in the tissues along the xylem stream. This spatial crystal pattern suggests a role for calcium oxalate formation in regulating calcium transport and partitioning to edible organs such as seeds. To investigate this potential role, microscopic and biochemical comparisons were conducted on the different tissues of Medicago truncatula wild-type and the calcium oxalate defective (cod) 5 which lacks the ability to accumulate prismatic crystals in the cells adjacent to the vascular bundles. Calcium measurements showed that cod5 seeds had more calcium and cod5 pods contained less calcium than the corresponding wild-type tissues. Roots, stems, and leaves from cod5 and wild-type had similar calcium content. Although cod5 was devoid of prismatic crystals, cod5 pods were observed to form druse crystals of calcium oxalate not found in wild-type pods. Taken together these findings suggest a functional role for calcium oxalate formation in regulating calcium transport to the seeds. Regulating calcium uptake at the roots also appeared to be another point of control in determining seed calcium content. Overall, regulating the long distance transport and partitioning of calcium to the seeds appears to be a complex process with multiple points of control.

  4. Morphological control of calcium oxalate particles in the presence of poly-(styrene-alt-maleic acid)

    NASA Astrophysics Data System (ADS)

    Yu, Jiaguo; Tang, Hua; Cheng, Bei; Zhao, Xiujian

    2004-10-01

    Calcium oxalate (CaOx) particles exhibiting different shapes and phase structures were fabricated by a simple precipitation reaction of sodium oxalate with calcium chloride in the absence and presence of poly-(styrene-alt-maleic acid) (PSMA) as a crystal modifier at room temperature. The as-obtained products were characterized with scanning electron microscopy (SEM) and X-ray diffraction (XRD). The effects of reaction conditions including pH, [Ca2+]/[C2O42-] ratio and concentration of PSMA and CaC2O4 on the crystal forms and morphologies of the as-obtained calcium oxalate were investigated. The results show that various crystal morphologies of calcium oxalate, such as parallelograms, plates, spheres, bipyramids etc. can be obtained depending on the experimental conditions. Higher polymer concentration favors formation of the metastable calcium oxalate dihydrate (COD) crystals. Lower pH is beneficial to the formation of plate-like CaOx crystals. Especially, the monodispersed parallelogram-like CaOx crystals can be produced by PSMA as an additive at pH 2. PSMA may act as a good inhibitor for urolithiasis since it induces the formation of COD and reduces the particle size of CaOx. This research may provide new insight into the morphological control of CaOx particles and the prevention of urolithiasis.

  5. Characterization of calcium oxalate biominerals in Pereskia species (Cactaceae).

    PubMed

    Monje, Paula V; Baran, Enrique J

    2009-01-01

    Calcium oxalate druses were isolated from the stems and leaves of six Pereskioideae family members and investigated by infrared spectroscopy, showing that in all samples the biomineral was present in the form of whewellite, CaC2O4 x H2O. As Pereskia is thought to represent the "ancestral" condition of the leafless stem-succulent cacti, these results suggest that the biomineralization of calcium oxalate in Cactaceae represents a primitive characteristic of the group and also support a close genetic relationship between Pereskia and Opuntia.

  6. Evidence that serum calcium oxalate supersaturation is a consequence of oxalate retention in patients with chronic renal failure.

    PubMed Central

    Worcester, E M; Nakagawa, Y; Bushinsky, D A; Coe, F L

    1986-01-01

    Serum oxalate rises in uremia because of decreased renal clearance, and crystals of calcium oxalate occur in the tissues of uremic patients. Crystal formation suggests that either uremic serum is supersaturated with calcium oxalate, or local oxalate production or accumulation causes regional supersaturation. To test the first alternative, we ultrafiltered uremic serum and measured supersaturation with two different methods previously used to study supersaturation in urine. First, the relative saturation ratio (RSR), the ratio of the dissolved calcium oxalate complex to the thermodynamic calcium oxalate solubility product, was estimated for 11 uremic (before and after dialysis) and 4 normal serum samples using a computer program. Mean ultrafiltrate oxalate predialysis was 89 +/- 8 microM/liter (+/- SEM), 31 +/- 4 postdialysis, and 10 +/- 3 in normals. Mean RSR was 1.7 +/- 0.1 (predialysis), 0.7 +/- 0.1 (postdialysis), and 0.2 +/- 0.1 (normal), where values greater than 1 denote supersaturation, less than 1, undersaturation. Second, the concentration product ratio (CPR), the ratio of the measured calcium oxalate concentration product before to that after incubation of the sample with calcium oxalate monohydrate crystal, was measured in seven uremic and seven normal serum ultrafiltrates. Mean oxalate was 91 +/- 11 (uremic) and 8 +/- 3 (normal). Mean CPR was 1.4 +/- 0.2 (uremic) and 0.2 +/- 0.1 (normal). Predialysis, 17 of 18 uremic ultrafiltrates were supersaturated with respect to calcium oxalate. The degree of supersaturation was correlated with ultrafiltrate oxalate (RSR, r = 0.99, r = 29, P less than 0.001; CPR, r = 0.75, n = 11, P less than 0.001). A value of ultrafiltrate oxalate of 50 microM/liter separated undersaturated from supersaturated samples and occurred at a creatinine of approximately 9.0 mg/dl. PMID:3711339

  7. The bioavailability of calcium in spinach and calcium-oxalate to calcium-deficient rats.

    PubMed

    Kikunaga, S; Arimori, M; Takahashi, M

    1988-04-01

    We estimated the utilization of calcium in spinach and calcium-oxalate to calcium-deficient rats, and the effect of oxalic acid on absorption of dietary calcium by using calcium-deficient rats. The body weight gain of the calcium-deficient rats for 8 days receiving a calcium-deficient diet supplemented with raw-powdered spinach (R-sp), boiled-powdered spinach (B-sp), or calcium-oxalate (Ca-ox), and a control diet supplemented with oxalic acid (OX-C) were 4.8, 2.8, 4.9, and 5.1 g, respectively. The calcium content in the liver and kidney of the rats receiving R-sp, B-sp, Ca-ox, and OX-C diets significantly increased as compared with the calcium-deficient rats. Significant differences in the liver calcium levels were not observed among the rats receiving various additional diets, though the content in the kidneys of the rats receiving R-sp, B-sp, Ca-ox, and OX-C diets were 28.0, 21.5, 0.11, and 0.59 mg, respectively. An especially large amount of calcium was accumulated in the kidneys of the rats receiving R-sp and B-sp diets. The calcium concentration in the serum of the rats receiving Ca-ox and OX-C diets was higher than the calcium concentration in the serum of the R-sp, B-sp, and calcium-deficient rats. The calcium content in the left tibiae of the rats receiving Ca-ox and OX-C diets was higher than that of the rats receiving R-sp and B-sp diets. The breaking force of the right tibiae of the rats was highest in the OX-C group, and higher in the R-sp and Ca-ox groups than the breaking force of the right tibiae of the rats fed on B-sp diet. The alkaline phosphatase activity in the small intestines of the rats rose in the order of the R-sp, B-sp, and Ca-ox groups, although significant differences of the activity were not observed between the Ca-ox and the OX-C groups. The calcium retention of the rats receiving the calcium-deficient, R-sp, B-sp, Ca-ox, and OX-C diets was -18.5, 35.2, 25.6, 41.6, and 45.8%, respectively. About 35% of the calcium in the spinach was

  8. Arthritis associated with calcium oxalate crystals in an anephric patient treated with peritoneal dialysis

    SciTech Connect

    Rosenthal, A.; Ryan, L.M.; McCarty, D.J.

    1988-09-02

    The authors report a case of calcium oxalate arthropathy in a woman undergoing intermittent peritoneal dialysis who was not receiving pharmacologic doses of ascorbic acid. She developed acute arthritis, with calcium oxalate crystals in Heberden's and Bouchard's nodes, a phenomenon previously described in gout. Intermittent peritoneal dialysis may be less efficient than hemodialysis in clearing oxalate, and physicians should now consider calcium oxalate-associated arthritis in patients undergoing peritoneal dialysis who are not receiving large doses of ascorbic acid.

  9. Oxalate reduces calcium availability in the pads of the prickly pear cactus through formation of calcium oxalate crystals.

    PubMed

    McConn, Michele M; Nakata, Paul A

    2004-03-10

    The pads (nopales) of the prickly pear cactus are considered to be a good source of minerals and other nutrients on the basis of compositional analysis. In this study, this analysis is taken a step further by assessing the availability of selected minerals in nopales using an in vitro digestion and dialysis method. The results obtained suggest that although nopales are enriched in a number of minerals, their tissue calcium is not freely available. Microscopic analysis, energy-dispersive X-ray microanalysis, and oxalate measurements suggest that this reduction in available calcium is a result of its sequestration in the form of calcium oxalate crystals. The issue of mineral availability in plant foods is important when the dependence of many populations around the world on plant foods as their main source of minerals and other nutrients is considered.

  10. Effect of Aerva lanata on calcium oxalate urolithiasis in rats.

    PubMed

    Soundararajan, P; Mahesh, R; Ramesh, T; Begum, V Hazeena

    2006-12-01

    Calcium oxalate (CaOx) stone was induced in rats using 0.75% of ethylene glycol in drinking water for 28 days. Ethylene glycol treated rats showed significant increase in the activities of oxalate synthesizing enzymes such as glycolic acid oxidase (GAO) in liver and lactate dehydrogenase (LDH) in liver and kidney. CaOx crystal deposition, as indicated by increased excretion of stone-forming constituents in urine, such as calcium, oxalate, uric acid, phosphorus and protein and decreased concentration of inhibitors, such as citrate and magnesium was observed in ethylene glycol induced urolithic rats. Histopathological studies also confirmed the deposition of CaOx crystals. Administration of Aerva lanata aqueous suspension (2g/kg body wt/dose/day for 28 days) to CaOx urolithic rats had reduced the oxalate synthesizing enzymes, diminished the markers of crystal deposition in the kidney. The results of the present study confirmed that A. lanata can be used as an curative agent for urolithiasis.

  11. Spectroscopic study of the inhibition of calcium oxalate calculi by Larrea tridentata

    NASA Astrophysics Data System (ADS)

    Pinales, Luis Alonso

    dipyramidal crystal structure of the calcium oxalate crystals grown with Larrea tridentata. Comparison between XRD experimental and simulated data, besides corroborating with our previous results, show that each sample is a combination of different structures.

  12. Do thiazides prevent recurrent idiopathic renal calcium oxalate stones?

    PubMed

    Wolf, H; Brocks, P; Dahl, C

    1983-01-01

    In a double-blind controlled clinical trial 62 patients with recurrent idiopathic renal calcium oxalate stone formation were allocated either to treatment with bendroflumethiazide, 2.5 mg three times a day, or placebo. In each group the rate of stone formation during medication (average follow-up period 36 months) was compared with the rate of stone formation before medication (average control period 36 months). In both groups a similar striking fall in the rate of stone formation was found, indicating that thiazides in this study did not alter the spontaneous course of idiopathic renal calcium oxalate stone formation. It is doubtful whether life-long prophylaxis with thiazide is justified in patients with a moderate rate of stone formation.

  13. Characterization of calcium oxalates generated as biominerals in cacti.

    PubMed

    Monje, Paula V; Baran, Enrique J

    2002-02-01

    The chemical composition and morphology of solid material isolated from various Cactaceae species have been analyzed. All of the tested specimens deposited high-purity calcium oxalate crystals in their succulent modified stems. These deposits occurred most frequently as round-shaped druses that sometimes coexist with abundant crystal sand in the tissue. The biominerals were identified either as CaC(2)O(4).2H(2)O (weddellite) or as CaC(2)O(4).H(2)O (whewellite). Seven different species from the Opuntioideae subfamily showed the presence of whewellite, and an equal number of species from the Cereoideae subfamily showed the deposition of weddellite. The chemical nature of these deposits was assessed by infrared spectroscopy. The crystal morphology of the crystals was visualized by both conventional light and scanning electron microscopy. Weddellite druses were made up of tetragonal crystallites, whereas those from whewellite were most often recognized by their acute points and general star-like shape. These studies clearly demonstrated that members from the main traditional subfamilies of the Cactaceae family could synthesize different chemical forms of calcium oxalate, suggesting a definite but different genetic control. The direct relationship established between a given Cactaceae species and a definite calcium oxalate biomineral seems to be a useful tool for plant identification and chemotaxonomy.

  14. The electrokinetic behavior of calcium oxalate monohydrate in macromolecular solutions

    NASA Technical Reports Server (NTRS)

    Curreri, P. A.; Onoda, G. Y., Jr.; Finlayson, B.

    1988-01-01

    Electrophoretic mobilities were measured for calcium oxalate monohydrate (COM) in solutions containing macromolecules. Two mucopolysaccharides (sodium heparin and chrondroitin sulfate) and two proteins (positively charged lysozyme and negatively charged bovine serum albumin) were studied as adsorbates. The effects of pH, calcium oxalate surface charge (varied by calcium or oxalate ion activity), and citrate concentration were investigated. All four macromolecules showed evidence for chemical adsorption. The macromolecule concentrations needed for reversing the surface charge indicated that the mucopopolysacchrides have greater affinity for the COM surface than the proteins. The amount of proteins that can chemically adsorb appears to be limited to approximately one monomolecular layer. When the surface charge is high, an insufficient number of proteins can chemically adsorb to neutralize or reverse the surface charge. The remaining surface charge is balanced by proteins held near the surface by longer range electrostatic forces only. Citrate ions at high concentrations appear to compete effectively with the negative protein for surface sites but show no evidence for competing with the positively charged protein.

  15. Characterization of Calcium Oxalates Generated as Biominerals in Cacti1

    PubMed Central

    Monje, Paula V.; Baran, Enrique J.

    2002-01-01

    The chemical composition and morphology of solid material isolated from various Cactaceae species have been analyzed. All of the tested specimens deposited high-purity calcium oxalate crystals in their succulent modified stems. These deposits occurred most frequently as round-shaped druses that sometimes coexist with abundant crystal sand in the tissue. The biominerals were identified either as CaC2O4.2H2O (weddellite) or as CaC2O4.H2O (whewellite). Seven different species from the Opuntioideae subfamily showed the presence of whewellite, and an equal number of species from the Cereoideae subfamily showed the deposition of weddellite. The chemical nature of these deposits was assessed by infrared spectroscopy. The crystal morphology of the crystals was visualized by both conventional light and scanning electron microscopy. Weddellite druses were made up of tetragonal crystallites, whereas those from whewellite were most often recognized by their acute points and general star-like shape. These studies clearly demonstrated that members from the main traditional subfamilies of the Cactaceae family could synthesize different chemical forms of calcium oxalate, suggesting a definite but different genetic control. The direct relationship established between a given Cactaceae species and a definite calcium oxalate biomineral seems to be a useful tool for plant identification and chemotaxonomy. PMID:11842173

  16. In vivo Drosophilia genetic model for calcium oxalate nephrolithiasis

    PubMed Central

    Hirata, Taku; Cabrero, Pablo; Berkholz, Donald S.; Bondeson, Daniel P.; Ritman, Erik L.; Thompson, James R.; Dow, Julian A. T.

    2012-01-01

    Nephrolithiasis is a major public health problem with a complex and varied etiology. Most stones are composed of calcium oxalate (CaOx), with dietary excess a risk factor. Because of complexity of mammalian system, the details of stone formation remain to be understood. Here we have developed a nephrolithiasis model using the genetic model Drosophila melanogaster, which has a simple, transparent kidney tubule. Drosophilia reliably develops CaOx stones upon dietary oxalate supplementation, and the nucleation and growth of microliths can be viewed in real time. The Slc26 anion transporter dPrestin (Slc26a5/6) is strongly expressed in Drosophilia kidney, and biophysical analysis shows that it is a potent oxalate transporter. When dPrestin is knocked down by RNAi in fly kidney, formation of microliths is reduced, identifying dPrestin as a key player in oxalate excretion. CaOx stone formation is an ancient conserved process across >400 My of divergent evolution (fly and human), and from this study we can conclude that the fly is a good genetic model of nephrolithiasis. PMID:22993075

  17. In vivo Drosophilia genetic model for calcium oxalate nephrolithiasis.

    PubMed

    Hirata, Taku; Cabrero, Pablo; Berkholz, Donald S; Bondeson, Daniel P; Ritman, Erik L; Thompson, James R; Dow, Julian A T; Romero, Michael F

    2012-12-01

    Nephrolithiasis is a major public health problem with a complex and varied etiology. Most stones are composed of calcium oxalate (CaOx), with dietary excess a risk factor. Because of complexity of mammalian system, the details of stone formation remain to be understood. Here we have developed a nephrolithiasis model using the genetic model Drosophila melanogaster, which has a simple, transparent kidney tubule. Drosophilia reliably develops CaOx stones upon dietary oxalate supplementation, and the nucleation and growth of microliths can be viewed in real time. The Slc26 anion transporter dPrestin (Slc26a5/6) is strongly expressed in Drosophilia kidney, and biophysical analysis shows that it is a potent oxalate transporter. When dPrestin is knocked down by RNAi in fly kidney, formation of microliths is reduced, identifying dPrestin as a key player in oxalate excretion. CaOx stone formation is an ancient conserved process across >400 My of divergent evolution (fly and human), and from this study we can conclude that the fly is a good genetic model of nephrolithiasis.

  18. Plant calcium oxalate crystal formation, function, and its impact on human health

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crystals of calcium oxalate have been observed among members from most taxonomic groups of photosynthetic organisms ranging from the smallest algae to the largest trees. The biological roles for calcium oxalate crystal formation in plant growth and development include high capacity calcium regulatio...

  19. Growth of calcium oxalate monohydrate at phospholipid Langmuir monolayers

    NASA Astrophysics Data System (ADS)

    Whipps, Scott; Khan, Saeed R.; Jeffrey O'Palko, F.; Backov, Rénal; Talham, Daniel R.

    1998-08-01

    Calcium oxalate monohydrate crystals have been nucleated from metastable solutions at Langmuir monolayers of the phospholipids dipalmitoylphosphatidylglycerol (DPPG), dipalmitoylphosphatidylserine and dipalmitoylphosphatidylcholine and the fatty acid arachidic acid. The phospholipid monolayers were used as model systems for domains of pure lipid in cellular media as part of investigations of their potential role in the nucleation of calcium oxalate in the urinary tract. Crystal formation was monitored at the air/water interface using Brewster angle microscopy and in transferred films using SEM and TEM. For each Langmuir monolayer, it was observed that nucleation is heterogeneous and is selective with respect to the orientation and morphology of the precipitated crystals with up to 90% of crystals growing with the ( 1 0 1¯) face oriented towards the monolayer interface. The selectivity is attributed to calcium binding at the lipid monolayer favoring formation of the calcium-rich ( 1 0 1¯) face. The behavior at each monolayer was similar, although a higher rate of crystal formation was observed at the anionic DPPG interface.

  20. Increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate.

    PubMed

    Morris, Jay; Nakata, Paul A; McConn, Michele; Brock, Amanda; Hirschi, Kendal D

    2007-07-01

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the model forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 M. truncatula mutant was identified which contains identical calcium concentrations to wild-type, but contains no oxalate crystals. In this study, equal number of male and female mice were randomly grouped and then fed one of four 45Ca-containing diets: M. truncatula extrinsically or intrinsically labeled, and cod5 extrinsically or intrinsically labeled. Absorption of the tracer was determined in the legs one day after consumption. The absorption was similar in the M. truncatula and cod5 extrinsically labeled diets; however, in the intrinsically labeled diets, calcium absorption was 22.87% (P < 0.001) higher in mice fed cod5. Our study presents the first genetic evidence demonstrating the nutritional impact of removing oxalate crystals from foods.

  1. Calcium oxalate crystal growth in human urinary stones

    SciTech Connect

    Kim, K.M.; Johnson, F.B.

    1981-01-01

    Calcium oxalate stones are very common and increasing. Crystal growth is no less important than the crystal nucleation in the pathogenesis of stone formation. The crystal growth was studied in human calcium oxalate stones by a combined electron microscopy and x-ray diffraction. The main mode of weddellite growth was interpenetration twinning of tetrahedral bipyramids. Bipyramids may form as initial crystal seeds, develop from anhedral crystals (crystals which lack flat symmetric faces) of spherular or mulberry shape, develop on the surface of preformed bipyramids by spiral dislocation mechanisms, or develop on whewellite crystal by heterogeneous nucleation and epitaxy. Heterogeneous nucleations of whewellite on weddellite, and calcium apatite on whewellite were also observed. Whewellite grew mainly by parallel twinning. Interpenetration twinning was exceptional. Transformation of anhedral to euhedral (completely bounded by flat faces that are set ar fixed angles to one another) whewellite occurred by parallel fissurations followed by brick wall like stacking of the crystals, while euhedral transformation of weddellite occurred by protrusion of bipyramids frm anhedral crystal surface. Occasionally, an evidence of crystal dissolution was noted. Although an aggregation of crystals is believed to play a pivotal role in stone nidus formation, growth in size of the formed crystals, and twinning and epitactic crystal intergrowth apparently play a significant role in the obstructive urinary stone formation.

  2. Calcium oxalate calculi-induced clusterin expression in kidney.

    PubMed

    Li, Jin-Yi; Liu, Junjiang; Jiang, Junyi; Pumill, Chris; Elaiho, Cordelia; Zhang, Yunxia; Li, Shoubin; Zhou, Tie

    2015-10-01

    The aim of the study was to investigate clusterin expression in the kidney and evaluate the urine clusterin level in the kidney stone formers. (1) In vitro, we treated the Madin-Darby canine kidney (MDCK) cell line with different concentrations of calcium oxalate (CaOx), and then the clusterin protein expression in the cells was evaluated by Western blotting. (2) Kidney stone patients who received percutaneous nephrolithotomy were enrolled in our study. Urine samples were collected before surgery, the kidney punctured to obtain kidney tissue guided by ultrasound intraoperatively. Clusterin expression in the human kidney tissue was evaluated by immunochemistry. The urine clusterin level was determined by enzyme-linked immunosorbent assay. Non-kidney disease subjects were chosen as controls. In vitro, the clusterin expression was up-regulated in the MDCK cells induced by CaOx. The study included 49 patients and 41 non-kidney disease subjects. All calculi were composed of calcium oxalate monohydrate or calcium oxalate dihydrate and a few also contained protein or uric acid. Mean ± SD urine clusterin level was 17.47 ± 18.61 μg/ml in patients, and 3.31 ± 5.42 μg/ml in non-kidney disease subjects, respectively (p < 0.001). Immunohistochemistry revealed the clusterin was located in the cytoplasm of the renal distal and collecting tubular epithelial cells. Also the tissue clusterin expression increased significantly in the kidney stone formers compared to the control groups (p = 0.001). CaOx could induce clusterin expression in renal tubular cells, and increase clusterin levels in the kidney and urine from the kidney stone formers.

  3. Calcium Oxalate Stones Are Frequently Found Attached to Randall's Plaque

    SciTech Connect

    Matlaga, Brian R.

    2007-04-05

    The exact mechanisms of the crystallization processes that occur during the formation of calcium oxalate calculi are controversial. Over six decades ago, Alexander Randall reported on a series of cadaveric renal units in which he observed calcium salt deposits on the tips of the renal papilla. Randall hypothesized that these deposits, eponymously termed Randall's plaque, would be the ideal site for stone formation, and indeed in a number of specimens he noted small stones attached to the papillae. With the recent advent of digital endoscopic imaging and micro computerized tomography (CT) technology, it is now possible to inspect the renal papilla of living, human stone formers and to study the attached stone with greater scrutiny.

  4. Raman spectroscopy study of calcium oxalate extracted from cacti stems.

    PubMed

    Frausto-Reyes, Claudio; Loza-Cornejo, Sofia; Terrazas, Teresa; Terrazas, Tania; Miranda-Beltrán, María de la Luz; Aparicio-Fernández, Xóchitl; López-Macías, Brenda M; Morales-Martínez, Sandra E; Ortiz-Morales, Martín

    2014-01-01

    To find markers that distinguish the different Cactaceae species, by using near infrared Raman spectroscopy and scanning electron microscopy, we studied the occurrence, in the stem, of solid deposits in five Cactaceae species (Coryphantha clavata, Ferocactus latispinus, Opuntia ficus-indica, O. robusta, and O. strepthacantha) collected from their natural habitats from a region of México. The deposits in the tissues usually occurred as spheroidal aggregates, druses, or prismatic crystals. From the Raman spectra, the crystals were identified either as calcium oxalate monohydrate (CaC2O4·H2O) or calcium oxalate dihydrate (CaC2O4·2H2O). Opuntia species (subfamily Opuntioideae) showed the presence of CaC2O4·H2O, and the deposition of CaC2O4·2H2O was present in C. clavata and F. latispinus (subfamily Cactoideae, Cacteae tribe). As a punctual technique, Raman spectroscopy seems to be a useful tool to identify crystal composition. In addition to allowing the analysis of crystal morphology, this spectroscopic technique can be used to identify Cactaceae species and their chemotaxonomy.

  5. Characterization of calcium oxalate defective (cod) 3 mutant from Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many plants invest a considerable amount of resources and energy into the formation of calcium oxalate crystals. Assigned roles for plant crystal formation include functions in defense, calcium regulation, and aluminum tolerance. From a human health standpoint, oxalate present in edible plant tiss...

  6. Contribution of dietary oxalate to urinary oxalate excretion

    NASA Technical Reports Server (NTRS)

    Holmes, R. P.; Goodman, H. O.; Assimos, D. G.

    2001-01-01

    BACKGROUND: The amount of oxalate excreted in urine has a significant impact on calcium oxalate supersaturation and stone formation. Dietary oxalate is believed to make only a minor (10 to 20%) contribution to the amount of oxalate excreted in urine, but the validity of the experimental observations that support this conclusion can be questioned. An understanding of the actual contribution of dietary oxalate to urinary oxalate excretion is important, as it is potentially modifiable. METHODS: We varied the amount of dietary oxalate consumed by a group of adult individuals using formula diets and controlled, solid-food diets with a known oxalate content, determined by a recently developed analytical procedure. Controlled solid-food diets were consumed containing 10, 50, and 250 mg of oxalate/2500 kcal, as well as formula diets containing 0 and 180 mg oxalate/2500 kcal. Changes in the content of oxalate and other ions were assessed in 24-hour urine collections. RESULTS: Urinary oxalate excretion increased as dietary oxalate intake increased. With oxalate-containing diets, the mean contribution of dietary oxalate to urinary oxalate excretion ranged from 24.4 +/- 15.5% on the 10 mg/2500 kcal/day diet to 41.5 +/- 9.1% on the 250 mg/2500 kcal/day diet, much higher than previously estimated. When the calcium content of a diet containing 250 mg of oxalate was reduced from 1002 mg to 391 mg, urinary oxalate excretion increased by a mean of 28.2 +/- 4.8%, and the mean dietary contribution increased to 52.6 +/- 8.6%. CONCLUSIONS: These results suggest that dietary oxalate makes a much greater contribution to urinary oxalate excretion than previously recognized, that dietary calcium influences the bioavailability of ingested oxalate, and that the absorption of dietary oxalate may be an important factor in calcium oxalate stone formation.

  7. Calcium oxalate monohydrate precipitation investigation by thermometric method

    NASA Astrophysics Data System (ADS)

    Söhnel, O.; Costa-Bauzá, A.; Velich, V.

    1993-01-01

    Calcium oxalate monohydrate (COM) precipitation from diluted solutions of 100 mol m -3 ionic strength at 25°C was studied by an isoperibolic reaction twin calorimeter. The molar reaction enthalpy was determined as - 17.5 kJ mol -1. Results achieved with a pure system were highly reproducible. Citrate, pyrophosphate and phytate retard COM precipitation that is manifested mainly by an induction period appearance and a decrease of the initial precipitation rate. Effect of the studied impurities on individual precipitation experiments carried out under identical conditions was to some extent "random", i.e. the reaction extent reached at arbitrary time considerably differed for individual experiments. Impurity effectiveness in retarding spontaneous precipitation increases in succession citrate < pyrophosphate < phytate.

  8. Oxalate co-precipitation synthesis of calcium zirconate and calcium titanate powders.

    SciTech Connect

    Hernandez-Sanchez, Bernadette A.; Tuttle, Bruce Andrew

    2009-06-01

    Fine powders of calcium zirconate (CaZrO{sub 3}, CZ) and calcium titanate (CaTiO{sub 3}, CT) were synthesized using a nonaqueous oxalate co-precipitation route from Ca(NO{sub 3}){sub 2}{center_dot}4 H{sub 2}O and group(IV) n-butoxides (Ti(OBu{sup n}){sub 4} or Zr(OBu{sup n}){sub 4}). Several reaction conditions and batch sizes (2-35 g) were explored to determine their influence on final particle size, morphology, and phase. Characterization of the as-prepared oxalate precursors, oven dried oxalate precursors (60-90 C), and calcined powders (635-900 C) were analyzed with TGA/DTA, XRD, TEM, and SEM. Densification and sintering studies on pressed CZ pellets at 1375 and 1400 C were also performed. Through the developed oxalate co-precipitation route, densification temperatures for CZ were lowered by 125 C from the 1500 C firing temperature required for conventional mixed oxide powders. Low field electrical tests of the CZ pellets indicated excellent dielectric properties with dielectric constants of {approx}30 and a dissipation factor of 0.0004 were measured at 1 kHz.

  9. A simple method for quantitating the propensity for calcium oxalate crystallization in urine

    NASA Technical Reports Server (NTRS)

    Wabner, C. L.; Pak, C. Y.

    1991-01-01

    To assess the propensity for spontaneous crystallization of calcium oxalate in urine, the permissible increment in oxalate is calculated. The previous method required visual observation of crystallization with the addition of oxalate, this warranted the need for a large volume of urine and a sacrifice in accuracy in defining differences between small incremental changes of added oxalate. Therefore, this method has been miniaturized and spontaneous crystallization is detected from the depletion of radioactive oxalate. The new "micro" method demonstrated a marked decrease (p < 0.001) in the permissible increment in oxalate in urine of stone formers versus normal subjects. Moreover, crystallization inhibitors added to urine, in vitro (heparin or diphosphonate) or in vivo (potassium citrate administration), substantially increased the permissible increment in oxalate. Thus, the "micro" method has proven reliable and accurate in discriminating stone forming from control urine and in distinguishing changes of inhibitory activity.

  10. Exploring calcium oxalate crystallization: a constant composition approach.

    PubMed

    Kolbach-Mandel, Ann M; Kleinman, Jack G; Wesson, Jeffrey A

    2015-10-01

    Crystal growth rates have been extensively studied in calcium oxalate monohydrate (COM) crystallization, because COM crystals are the principal component in most kidney stones. Constant composition methods are useful for studying growth rates, but fail to differentiate concurrent nucleation and aggregation events. A constant composition method coupled with particle size determinations that addresses this deficiency was previously published for a calcium phosphate system, and this method was extended to COM crystallization in this report. A seeded constant composition experiment was combined with particle size determination and a separate near-equilibrium aggregation experiment to separate effects of growth rate, nucleation, and aggregation in COM crystal formation and to test the effects of various inhibitors relevant to stone formation. With no inhibitors present, apparent COM growth rates were heavily influenced by secondary nucleation at low seed crystal additions, but growth-related aggregation increased at higher seed crystal densities. Among small molecule inhibitors, citrate demonstrated growth rate inhibition but enhanced growth-related aggregation, while magnesium did not affect COM crystallization. Polyanions (polyaspartate, polyglutamate, or osteopontin) showed strong growth rate inhibition, but large differences in nucleation and aggregation were observed. Polycations (polyarginine) did not affect COM crystal growth or aggregation. Mixtures of polyanions and polycations produced a complicated set of growth rate, nucleation, and aggregation behaviors. These experiments demonstrated the power of combining particle size determinations with constant composition experiments to fully characterize COM crystallization and to obtain detailed knowledge of inhibitor properties that will be critical to understanding kidney stone formation.

  11. Exploring Calcium Oxalate Crystallization: A Constant Composition Approach

    PubMed Central

    Kolbach-Mandel, Ann M.; Kleinman, Jack G.; Wesson, Jeffrey A.

    2015-01-01

    Crystal growth rates have been extensively studied in calcium oxalate monohydrate (COM) crystallization, because COM crystals are the principal component in most kidney stones. Constant composition methods are useful for studying growth rates, but fail to differentiate concurrent nucleation and aggregation events. A constant composition method coupled with particle size determinations that addresses this deficiency was previously published for a calcium phosphate system, and this method was extended to COM crystallization in this report. A seeded constant composition experiment was combined with particle size determination and a separate near-equilibrium aggregation experiment to separate effects of growth rate, nucleation, and aggregation in COM crystal formation and to test the effects of various inhibitors relevant to stone formation. With no inhibitors present, apparent COM growth rates were heavily influenced by secondary nucleation at low seed crystal additions, but growth-related aggregation increased at higher seed crystal densities. Among small molecule inhibitors, citrate demonstrated growth rate inhibition but enhanced growth-related aggregation, while magnesium did not affect COM crystallization. Polyanions (polyaspartate, polyglutamate, or osteopontin) showed strong growth rate inhibition, but large differences in nucleation and aggregation were observed. Polycations (polyarginine) did not affect COM crystal growth or aggregation. Mixtures of polyanions and polycations produced a complicated set of growth rate, nucleation, and aggregation behaviors. These experiments demonstrated the power of combining particle size determinations with constant composition experiments to fully characterize COM crystallization and to obtain detailed knowledge of inhibitor properties that will be critical to understanding kidney stone formation. PMID:26016572

  12. [Urinary calcium oxalate supersaturation beyond nephrolithiasis. Relationship with tubulointerstitial damage].

    PubMed

    Toblli, Jorge E; Angerosa, Margarita; Stella, Inés; Ferder, León; Inserra, Felipe

    2003-01-01

    A number of studies have demonstrated that the urinary ion activity product (IAP) of calcium oxalate (CaOx), as an index of urinary CaOx supersaturation (SS), is higher in renal stone formers than in normal subjects. Besides, the relation between CaOx SS and lithogenesis, crystal CaOx exposition can produce tubular cell as well as renal interstitial lesions. The aim of our study was to evaluate the possible relationship between CaOx SS and tubulointerstitial (TI) damage in an animal model of hyperoxaluria. During four weeks, male Sprague-Dawley rats received: G1 (n = 8) control regular water, and G2 (n = 8) 1% ethylene glycol (ETG) (precursor for oxalates) in drinking water. In order to evaluate urinary CaOx SS, IAP assessed by Tisselius formula was performed. At the end of the study, renal lesions were evaluated by light microscopy and immunohistochemistry. Animals from G2 (ETG) presented higher (p < 0.01) values of: a) urinary oxalate excretion; b) urinary CaOx SS; c) crystalluria score; d) proteinuria; and lower (p < 0.01) creatinine clearance, with respect to the control group (G1). Moreover, pathology studies showed that rats from G2 (ETG), presented significant TI lesions characterized by a higher (p < 0.01) score of: a) tubular atrophy; inflammatory infiltrates (monocyte/macrophage); c) crystal deposits; d) intersticial fibrosis; e) interstitial alpha-smooth muscle actin; f) collagen type III; g) TI TGF beta 1 compared with G1 (control). Rats from G2 (ETG) presented a high correlation between urinary CaOx SS and most of the TI damage parameters evaluated, in especial with interstitial fibrosis. Both, inflammatory infiltrates and urinary CaOx SS were the most significant variables related to interstitial fibrosis. Finally, since hyperoxaluric animals showed higher urinary CaOx SS associated with higher renal TI damage, the results from this study suggest the presence of a tight link between urinary CaOx SS and renal TI damage. Considering these findings we

  13. Inhibition of crystallization of calcium oxalate by the extraction of Tamarix gallica L.

    PubMed

    Bensatal, Ahmed; Ouahrani, M R

    2008-12-01

    The main objective is to study the inhibitor effect of acid fraction of the extract of Tamarix gallica L on the crystallization of calcium oxalate. The extract of Tamarix gallica L is very rich by acid compounds that are used as an inhibitor of nephrolithiasis (calcium oxalate). Our study of the calcium oxalate crystallization is based on the model of turbidimetry by means of a spectrophotometer. The calcium oxalate formation is induced by the addition of oxalate solutions of sodium and of calcium chloride. The addition of inhibitor with various concentrations enabled us to give information on the percentage of inhibition. The comparison between the turbidimetric slopes with and without inhibitor gives the effectiveness of inhibitor for the acid fraction. By comparing the photographs of with and without inhibitor, we concluded that the extract of Tamarix gallica L acts at the stage of growth. The acid fraction of the extract of Tamarix gallica L gives an activity remarkable in the formation of urinary lithiasis (calcium oxalate); this effectiveness is due to the presence of functions of acid.

  14. Potassium citrate decreases urine calcium excretion in patients with hypocitraturic calcium oxalate nephrolithiasis.

    PubMed

    Song, Yan; Hernandez, Natalia; Shoag, Jonathan; Goldfarb, David S; Eisner, Brian H

    2016-04-01

    Two previous studies (<10 patients each) have demonstrated that alkali therapy may reduce urine calcium excretion in patients with calcium oxalate nephrolithiasis. The hypothesized mechanisms are (1) a decrease in bone turnover due to systemic alkalinization by the medications; (2) binding of calcium by citrate in the gastrointestinal tract; (3) direct effects on TRPV5 activity in the distal tubule. We performed a retrospective review of patients on potassium citrate therapy to evaluate the effects of this medication on urinary calcium excretion. A retrospective review was performed of a metabolic stone database at a tertiary care academic hospital. Patients were identified with a history of calcium oxalate nephrolithiasis and hypocitraturia who were on potassium citrate therapy for a minimum of 3 months. 24-h urine composition was assessed prior to the initiation of potassium citrate therapy and after 3 months of therapy. Patients received 30-60 mEq potassium citrate by mouth daily. Inclusion criterion was a change in urine potassium of 20 mEq/day or greater, which suggests compliance with potassium citrate therapy. Paired t test was used to compare therapeutic effect. Twenty-two patients were evaluated. Mean age was 58.8 years (SD 14.0), mean BMI was 29.6 kg/m(2) (SD 5.9), and gender prevalence was 36.4% female:63.6% male. Mean pre-treatment 24-h urine values were as follows: citrate 280.0 mg/day, potassium 58.7 mEq/day, calcium 216.0 mg/day, pH 5.87. Potassium citrate therapy was associated with statistically significant changes in each of these parameters-citrate increased to 548.4 mg/day (p < 0.0001), potassium increased to 94.1 mEq/day (p < 0.0001), calcium decreased to 156.5 mg/day (p = 0.04), pH increased to 6.47 (p = 0.001). Urine sodium excretion was not different pre- and post-therapy (175 mEq/day pre-therapy versus 201 mEq/day post-therapy, p = NS). Urinary calcium excretion decreased by a mean of 60 mg/day on potassium citrate therapy-a nearly 30

  15. [Study on inhibitory effect of EGCG on Calcium oxalate nephrolithiasis in rats and its related mechanism].

    PubMed

    Zhou, Yong; Wang, Shuo; Tang, Chun-bo

    2015-04-01

    In the study, the inhibitory effect of epigallocatechin gallate (EGCG) on Calcium oxalate nephrolithiasis and its possible mechanism were investigated. The rat Calcium oxalate nephrolithiasis model was induced through the combined oral administration of ethylene glycol and ammonium chloride, which was intervened with EGCG. Rat blood samples were collected to detect blood creatinine (Cr), blood urea nitrogen (BUN) and blood calcium. Rat urine samples were collected to observe and compare 24-hour urine volume, oxalic acid (Ox) and calcium in urine. Renal samples were collected to prepare tissue slices and observe the pathological changes in Calcium oxalate nephrolithiasis. The expression of osteopontin (OPN) in renal tissues was evaluated by Real-time PCR and Western blot. According to the results, compared with normal rats, rats in the nephrolithiasis model showed significant increases in Cr, BUN, urine Calcium, urine Ox and renal OPN expression (P < 0.05), but obvious decrease in 24-hour urine volume (P < 0.05); Compared with rats with nephrolithiasis, those processed with EGCG revealed remarkable declines in Cr, BUN, urine Calcium and urine Ox (P < 0.05), with significant rise in 24-hour urine volume (P < 0.05) in a concentration-dependent manner. Additionally, compared with the control group, nephrolithiasis rats showed significant pathological changes in Calcium oxalate calculus. After ECCG treatment, the renal pathological changes and OPN expression attenuated significantly in a concentration-dependent manner. The results showed that EGCG inhibits the formation of calcium oxalate nephrolithiasis in rats and shows a notable protective effect on renal functions.

  16. The genetic composition of Oxalobacter formigenes and its relationship to colonization and calcium oxalate stone disease

    PubMed Central

    Knight, John; Deora, Rajendar; Assimos, Dean G.; Holmes, Ross P.

    2013-01-01

    Oxalobacter formigenes is a unique intestinal organism that relies on oxalate degradation to meet most of its energy and carbon needs. A lack of colonization is a risk factor for calcium oxalate stone disease. Protection against calcium oxalate stone disease appears to be due to the oxalate degradation that occurs in the gut on low calcium diets with a possible further contribution from intestinal oxalate secretion. Much remains to be learned about how the organism establishes and maintains gut colonization and the precise mechanisms by which it modifies stone risk. The sequencing and annotation of the genomes of a Group 1 and a Group 2 strain of O. formigenes should provide the informatic tools required for the identification of the genes and pathways associated with colonization and survival. In this review we have identified genes that may be involved and where appropriate suggested how they may be important in calcium oxalate stone disease. Elaborating the functional roles of these genes should accelerate our understanding of the organism and clarify its role in preventing stone formation. PMID:23632911

  17. Genetically modified Medicago truncatula lacking calcium oxalate has increased calcium bioavailability and partially rescues vitamin D receptor knockout mice phenotypes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    How the distribution and sequestered form of plant macro/micro-nutrients influence their bioavailability, and ultimately impact human health, is poorly understood. The legume Medicago truncatula has a portion of its tissue calcium sequestered in the form of the calcium oxalate crystal, which reduces...

  18. Randall's plaque: pathogenesis and role in calcium oxalate nephrolithiasis.

    PubMed

    Evan, A; Lingeman, J; Coe, F L; Worcester, E

    2006-04-01

    The purpose of these studies was to test the hypothesis that Randall's plaque develops in unique anatomical sites of the kidney and their formation is conditioned by specific stone-forming pathophysiologies. We performed intraoperative papillary biopsies from kidneys of idiopathic-calcium oxalate (CaOx), intestinal bypass for obesity, brushite (BR) and cystine stone formers (SF) during percutaneous nephrolithotomy. Tissues were examined by infrared analysis and light and electron microscopy. Our analysis revealed a distinct pattern of mineral deposition and papillary pathology for each type of SF. CaOx SF had interstitial apatite crystals beginning at thin loops of Henle. These deposits termed Randall's plaque are thought to serve as sites for stone attachment. No tubular injury was noted. Intestinal bypass patients possessed intraluminal apatite deposits in inner medullary collecting ducts (IMCD) with associated cell injury. BR SF showed the most severe form of cortical and medullary changes with sites of Randall's plaque, and yellowish intraluminal deposits of apatite in IMCD. Cystine SF had plugging of ducts of Bellini with cystine crystals and apatite deposits in IMCD and loops of Henle. Intratubular sites of crystalline deposits were always associated to adjacent regions of interstitial fibrosis. The metabolic, anatomic, and surgical pathologic findings in four distinct groups of SF clearly show that 'the histology of the renal papilla from a stone former, is particular to the clinical setting'. We believe our approach to studying stone disease will provide insights into the pathogenesis of stone formation for each type of SF that will lead to improved clinical treatment.

  19. Prediction of calcium oxalate monohydrate stone composition during ureteroscopy

    NASA Astrophysics Data System (ADS)

    Hamidizedah, Reza; Melnyk, Megan; Teichman, Joel M. H.

    2012-02-01

    Introduction: Prior research shows that Ho:YAG lithotripsy produces tiny dust fragments at low pulse energy (0.2J). However, calcium oxalate monohydrate (COM) stones may not fragment at this low pulse energy setting. Stone composition is rarely known until after surgery and historically, attempts to predict stone composition on the basis of endoscopic stone appearance were unsuccessful. Current endoscopic technology permits visual details that previously were not evident. As COM appears black under ambient light, we attempt to predict COM stone composition at the time of ureteroscopy based on its endoscopic appearance. Methods: Consecutive subjects undergoing ureteroscopy for stone disease were studied. Any portion of the stone that appeared black under endoscopic vision was considered clinical evidence of COM. Predicted stone composition was correlated with post-operative calculus analysis. Results: 46 consecutive ureteroscopic stone cases were analyzed prospectively. 25 of 28 subjects (89%) with black stones had stones later proven to be COM by composition analysis, versus one of 18 patients (6%) with non-black stones that were COM (p<0.0001). A black endoscopic stone appearance had a positive predictive value for COM of 89% and a non-black endoscopic stone appearance had a negative predictive value for COM of 94% (sensitivity 96%, specificity 83%). Conclusions: COM may reasonably be predicted intra-operatively by its black endoscopic appearance. The clinical utility would be to use higher laser pulse energy settings than for non-COM compositions. This data raises the possibility that more sophisticated optical characterization of endoscopic stone appearance may prove to be a useful tool to predict stone composition.

  20. CALCIUM OXALATE STONE FRAGMENT AND CRYSTAL PHAGOCYTOSIS BY HUMAN MACROPHAGES

    PubMed Central

    Kusmartsev, Sergei; Dominguez-Gutierrez, Paul R.; Canales, Benjamin K.; Bird, Vincent G.; Vieweg, Johannes; Khan, Saeed R.

    2015-01-01

    Purpose In murine and human hyperoxaluric conditions, macrophages can be seen surrounding renal calcium oxalate (CaOx) crystal deposits. We hypothesize that macrophages play a role in degrading and destroying these deposits and investigated inflammatory response and phagocytic mechanisms when macrophages are exposed to human kidney stones and inorganic crystals. Materials and Methods Human monocytes were differentiated into resting, fully-differentiated macrophages by treating with recombinant human M-CSF or GM-CSF for 6 days. After confirming phenotype by flow cytometry, macrophages were exposed for 20 hours to fragments of sterile human CaOx stones or CaOx crystals. Crystal uptake was determined, and supernatant cytokine and chemokine profiles were analyzed using antibody arrays. qRT-PCR was used to validate mRNA profile expression. Results Under direct-vision fluorescent microscopy, activated human macrophages were noted to surround both stone fragments and synthesized crystals and destroy them in a step-by-step process that involved clathrin-mediated endocytosis and phagocytosis. An inflammatory cascade was released by macrophages, including chemokines CCL2, CCL3, interleukin-1 receptor antagonist (IL-1ra), complement component C5/C5a and IL-8. The response patterns to stone and crystal material was dependent on macrophage phenotype and activation status. Conclusions In our in vitro study, macrophages differentiated with M-CSF displayed a greater ability to phagocytize crystal deposits than those treated with GM-CSF. Following clathrin-mediated endocytosis, macrophages released a number of cytokines crucial for inflammatory immune response, suggesting that tissue macrophages play an important role in preventing kidney stone disease by removing and digesting interstitial renal crystal deposits. PMID:26626217

  1. Nanoscale observations of the effect of citrate on calcium oxalate precipitation on calcite surfaces.

    NASA Astrophysics Data System (ADS)

    Burgos-Cara, Alejandro; Ruiz-Agudo, Encarnacion; Putnis, Christine V.

    2016-04-01

    Calcium oxalate (CaC2O4ṡxH2O) minerals are naturally occurring minerals found in fossils, plants, kidney stones and is a by-product in some processes such as paper, food and beverage production [1,2]. In particular, calcium oxalate monohydrate phase (COM) also known as whewellite (CaC2O4ṡH2O), is the most frequently reported mineral phase found in urinary and kidney stones together with phosphates. Organic additives are well known to play a key role in the formation of minerals in both biotic and abiotic systems, either facilitating their precipitation or hindering it. In this regard, recent studies have provided direct evidence demonstrating that citrate species could enhance dissolution of COM and inhibit their precipitation. [3,4] The present work aims at evauate the influence of pH, citrate and oxalic acid concentrations in calcium oxalate precipitation on calcite surfaces (Island Spar, Chihuahua, Mexico) through in-situ nanoscale observation using in situ atomic force microscopy (AFM, Multimode, Bruker) in flow-through experiments. Changes in calcium oxalate morphologies and precipitated phases were observed, as well as the inhibitory effect of citrate on calcium oxalate precipitation, which also lead to stabilization an the amorphous calcium oxalate phase. [1] K.D. Demadis, M. Öner, Inhibitory effects of "green"additives on the crystal growth of sparingly soluble salts, in: J.T. Pearlman (Ed.), Green Chemistry Research Trends, Nova Science Publishers Inc., New York, 2009, pp. 265-287. [2] M. Masár, M. Zuborová, D. Kaniansky, B. Stanislawski, Determination of oxalate in beer by zone electrophoresis on a chip with conductivity detection, J. Sep. Sci. 26 (2003) 647-652. [3] Chutipongtanate S, Chaiyarit S, Thongboonkerd V. Citrate, not phosphate, can dissolve calcium oxalate monohydrate crystals and detach these crystals from renal tubular cells. Eur J Pharmacol 2012;689:219-25. [4] Weaver ML, Qiu SR, Hoyer JR, Casey WH, Nancollas GH, De Yoreo JJ

  2. Effects of pyruvate salts, pyruvic acid, and bicarbonate salts in preventing experimental oxalate urolithiasis in rats.

    PubMed

    Ogawa, Y; Yamaguchi, K; Tanaka, T; Morozumi, M

    1986-05-01

    Sodium pyruvate, potassium pyruvate, pyruvic acid, sodium bicarbonate and potassium bicarbonate were added to a calcium-oxalate lithogenic diet (a glycolic-acid diet) in order to determine their effects in preventing lithogenicity. Male Wistar-strain rats who had been fed the glycolic-acid diet developed marked urinary calculi within four weeks. Rats in the sodium and potassium pyruvate groups had, however, almost no stones in the urinary system. Rats in the bicarbonate and pyruvic-acid groups showed slightly less effect than those in the pyruvate groups. Urinary oxalate excretion was high in all the groups during the experiment. The urinary oxalate concentration was relatively higher in the sodium-pyruvate group, and significantly higher in the potassium-pyruvate group, than in the glycolic-acid group. Urinary citrate excretion was high both in the pyruvate and bicarbonate groups; the urinary citrate concentration was, however, significantly higher in the pyruvate groups than in the bicarbonate groups at the fourth experimental week. The urinary calcium and magnesium concentrations were irrelevant to the diets administered. Therefore, it can be concluded that pyruvate salts inhibit urinary calculi formation, not by decreasing oxalate synthesis, but by increasing the urinary citrate concentration; bicarbonate salts work in the same manner, but a little less effectively.

  3. Genetic evidence for differences in the pathways of druse and prismatic calcium oxalate crystal formation in Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Current evidence supports a single pathway of oxalate biosynthesis utilising ascorbic acid as the precursor. In this study, we begin to address the possibility that more than one pathway of oxalate biosynthesis and calcium oxalate formation occurs in Medicago truncatula Gaertn. (cv. Jemalong genotyp...

  4. Developing precipitation modes for preventing the calcium-oxalate contamination of sugar beet pectins.

    PubMed

    Guo, Xiaoming; Meng, Hecheng; Zhu, Siming; Tang, Qiang; Pan, Runquan; Yu, Shujuan

    2015-09-01

    Effects of precipitation modes on the co-precipitation of insoluble oxalates particles during the purification of sugar beet pectins (SBP) from the extract were investigated. It was observed that soluble oxalate ions formed insoluble oxalate salts with calcium and precipitated with pectins during ethanol precipitation as pH of the medium increased and the solvent changed from water to ethanol-water mixture. Comparison among the employed precipitation methods revealed that both the dialysis-ethanol-precipitation and metal precipitation effectively prevented the calcium-oxalate contamination of SBP. Emulsifying properties of DEPP, EPP and MPP were also studied. It was observed that DEPP performed better than the remainder with respect to emulsifying ability. Based on these results, we concluded that the dialysis-ethanolic-precipitation can be a suitable method for improving the purity as well as emulsifying properties of the resulting pectins.

  5. Effects of magnesium salts in preventing experimental oxalate urolithiasis in rats.

    PubMed

    Ogawa, Y; Yamaguchi, K; Morozumi, M

    1990-08-01

    Magnesium oxide, magnesium hydroxide, magnesium sulfate, magnesium trisilicate, and magnesium citrate were added to a calcium-oxalate lithogenic diet in order to determine their effects in preventing lithogenesis. Male Wistar-strain rats which had been fed the glycolic-acid diet developed marked urinary calculi within four weeks. Rats in the magnesium-hydroxide, magnesium-citrate, and magnesium-trisilicate groups, however, had almost no stones in the urinary system. Rats in the magnesium-oxide and magnesium-sulfate groups showed significantly less effect than those in the former three groups. During the experimental period, the 24-hour urinary oxalate excretion and concentration were higher in the glycolic-acid group than in the other groups. The urinary citrate excretion and concentration were the highest in the magnesium-hydroxide and magnesium-citrate groups and higher in the magnesium-trisilicate and magnesium-oxide groups than in the magnesium-sulfate and glycolic-acid groups. Similar trends were observed in the urinary magnesium excretion and in its concentration. The urinary calcium excretion and concentration were higher in the experimental groups than in the glycolic-acid group. The urinary calcium/magnesium ratio remained mostly unchanged. Therefore, it can be concluded that alkaline magnesium salts increase the urinary calcium and magnesium concentrations, without changing the calcium/magnesium ratio, and inhibit urinary calculi formation, most likely by increasing the urinary citrate concentration.

  6. A retrospective study of the prevalence of calcium oxalate crystals in veterinary Aspergillus cases.

    PubMed

    Payne, Courtney L; Dark, Michael J; Conway, Julia A; Farina, Lisa L

    2017-01-01

    Fungi in the genus Aspergillus are some of the most common fungal pathogens in veterinary species, primarily affecting the respiratory tract. In both human and veterinary cases, calcium oxalate crystals have been documented in sites of Aspergillus infection. Cases in multiple species (16 birds, 15 horses, 5 dogs, 1 ox, and 1 dolphin) were identified that had either positive cultures for Aspergillus sp., or had conidiophores present that could be identified as belonging to the genus Aspergillus. Histologic slides were examined to confirm the presence of oxalate crystals and how often they were identified on the original report. Calcium oxalate deposition was detected in 14 of 38 cases examined, including A. fumigatus, A. versicolor, A. niger, and unspecified Aspergillus sp. infections. Calcium oxalate crystals were identified in 11 of 16 avian cases, as well as in 1 of 1 bovine, 1 of 15 equine, and 1 of 5 canine cases. Crystals were described in only 3 of the 14 original pathology reports of these cases, indicating that identification and reporting of crystals in histologic specimens could be improved. All the tissues with crystals were respiratory tissues with air interfaces, including nasal sinus, trachea, syrinx, lung, and air sac. In cases with crystals identified on H&E-stained sections, crystals were frequently not present or were fewer in number in tissue sections stained with Gomori methenamine silver and periodic acid-Schiff. Routine polarization of slides of fungal infections, especially in the respiratory tract, should be considered to check for calcium oxalate crystals.

  7. Peptides of Matrix Gla protein inhibit nucleation and growth of hydroxyapatite and calcium oxalate monohydrate crystals.

    PubMed

    Goiko, Maria; Dierolf, Joshua; Gleberzon, Jared S; Liao, Yinyin; Grohe, Bernd; Goldberg, Harvey A; de Bruyn, John R; Hunter, Graeme K

    2013-01-01

    Matrix Gla protein (MGP) is a phosphorylated and γ-carboxylated protein that has been shown to prevent the deposition of hydroxyapatite crystals in the walls of blood vessels. MGP is also expressed in kidney and may inhibit the formation of kidney stones, which mainly consist of another crystalline phase, calcium oxalate monohydrate. To determine the mechanism by which MGP prevents soft-tissue calcification, we have synthesized peptides corresponding to the phosphorylated and γ-carboxylated sequences of human MGP in both post-translationally modified and non-modified forms. The effects of these peptides on hydroxyapatite formation and calcium oxalate crystallization were quantified using dynamic light scattering and scanning electron microscopy, respectively. Peptides YGlapS (MGP1-14: YγEpSHEpSMEpSYELNP), YEpS (YEpSHEpSMEpSYELNP), YGlaS (YγESHESMESYELNP) and SK-Gla (MGP43-56: SKPVHγELNRγEACDD) inhibited formation of hydroxyapatite in order of potency YGlapS > YEpS > YGlaS > SK-Gla. The effects of YGlapS, YEpS and YGlaS on hydroxyapatite formation were on both crystal nucleation and growth; the effect of SK-Gla was on nucleation. YGlapS and YEpS significantly inhibited the growth of calcium oxalate monohydrate crystals, while simultaneously promoting the formation of calcium oxalate dihydrate. The effects of these phosphopeptides on calcium oxalate monohydrate formation were on growth of crystals rather than nucleation. We have shown that the use of dynamic light scattering allows inhibitors of hydroxyapatite nucleation and growth to be distinguished. We have also demonstrated for the first time that MGP peptides inhibit the formation of calcium oxalate monohydrate. Based on the latter finding, we propose that MGP function not only to prevent blood-vessel calcification but also to inhibit stone formation in kidney.

  8. Calcium Channels are Involved in Calcium Oxalate Crystal Formation in Specialized Cells of Pistia stratiotes L.

    PubMed Central

    VOLK, GAYLE M.; GOSS, LENORA J.; FRANCESCHI, VINCENT R.

    2004-01-01

    • Background and Aims Pistia stratiotes produces large amounts of calcium (Ca) oxalate crystals in specialized cells called crystal idioblasts. The potential involvement of Ca2+ channels in Ca oxalate crystal formation by crystal idioblasts was investigated. • Methods Anatomical, ultrastructural and physiological analyses were used on plants, fresh or fixed tissues, or protoplasts. Ca2+ uptake by protoplasts was measured with 45Ca2+, and the effect of Ca2+ channel blockers studied in intact plants. Labelled Ca2+ channel blockers and a channel protein antibody were used to determine if Ca2+ channels were associated with crystal idioblasts. • Key Results 45Ca2+ uptake was more than two orders of magnitude greater for crystal idioblast protoplasts than mesophyll protoplasts, and idioblast number increased when medium Ca was increased. Plants grown on media containing 1–50 µm of the Ca2+ channel blockers, isradipine, nifedipine or fluspirilene, showed almost complete inhibition of crystal formation. When fresh tissue sections were treated with the fluorescent dihydropyridine‐type Ca2+ channel blocker, DM‐Bodipy‐DHP, crystal idioblasts were intensely labelled compared with surrounding mesophyll, and the label appeared to be associated with the plasma membrane and the endoplasmic reticulum, which is shown to be abundant in idioblasts. An antibody to a mammalian Ca2+ channel α1 subunit recognized a single band in a microsomal protein fraction but not soluble protein fraction on western blots, and it selectively and heavily labelled developing crystal idioblasts in tissue sections. • Conclusions The results demonstrate that Ca oxalate crystal idioblasts are enriched, relative to mesophyll cells, in dihydropyridine‐type Ca2+ channels and that the activity of these channels is important to transport and accumulation of Ca2+ required for crystal formation. PMID:15087302

  9. Characterization of calcium oxalate biominerals in some (non-Cactaceae) succulent plant species.

    PubMed

    Monje, Paula V; Baran, Enrique J

    2010-01-01

    The water-accumulating leaves of crassulacean acid metabolism plants belonging to five different families were investigated for the presence of biominerals by infrared spectroscopic and microscopic analyses. Spectroscopic results revealed that the mineral present in succulent species of Agavaceae, Aizoaceae, and Asphodelaceae was calcium oxalate monohydrate (whewellite, CaC2O4 x H2O). Crystals were predominantly found as raphides or solitary crystals of various morphologies. However, representative Crassulaceae members and a succulent species of Asteraceae did not show the presence of biominerals. Overall, these results suggest no correlation between calcium oxalate generation and crassulacean acid metabolism in succulent plants.

  10. Calcium oxalate crystal deposition in a patient with Aspergilloma due to Aspergillus niger

    PubMed Central

    Oda, Miku; Wakayama, Megumi; Shibuya, Kazutoshi; Ogawa, Yukari; Inui, Toshiya; Yokoyama, Emi; Inoue, Manami; Shimoyamada, Hiroaki; Fujiwara, Masachika; Ota, Tomohiro; Takizawa, Hajime; Goto, Hajime

    2013-01-01

    Discrimination between aspergilloma and chronic necrotizing pulmonary aspergillosis (CNPA) based on radiological findings can difficult. We describe a patient with aspergilloma and organizing pneumonia that was possibly caused by Aspergillus niger infection and radiologically mimicked CNPA. A postmortem histological analysis showed diffuse alveolar damage that had originated in peri-cavitary lung parenchyma. Calcium oxalate or Aspergillus niger was located inside, but not outside the cavity in the right upper lobe. Calcium oxalate or other unknown hyphal bioactive components might provoke severe lung inflammation not only adjacent to the cavity, but also on the contralateral side. PMID:23991333

  11. The influence of crystal morphology on the kinetics of growth of calcium oxalate monohydrate

    NASA Astrophysics Data System (ADS)

    Millan, A.; Sohnel, O.; Grases, F.

    1997-08-01

    The growth of several calcium oxalate monohydrate seeds in the presence and absence of additives (phytate, EDTA and citrate) has been followed by potentiometry measurements. Growth rates have been calculated from precipitate curves by a cubic spline method and represented in logarithmic plots versus supersaturation. Crystal growth kinetics were found to be dependent on crystal morphology, crystal perfection and degree of aggregation. Some seeds were dissolving in supersaturated solutions. Other seeds showed an initial growth phase of high-order kinetics. The effect of the additives was also different on each seed. Three alternative mechanisms for calcium oxalate crystal growth are proposed.

  12. Proteomic analysis of a rare urinary stone composed of calcium carbonate and calcium oxalate dihydrate: a case report.

    PubMed

    Kaneko, Kiyoko; Matsuta, Yosuke; Moriyama, Manabu; Yasuda, Makoto; Chishima, Noriharu; Yamaoka, Noriko; Fukuuchi, Tomoko; Miyazawa, Katsuhito; Suzuki, Koji

    2014-03-01

    The objective of the present study was to investigate the matrix protein of a rare urinary stone that contained calcium carbonate. A urinary stone was extracted from a 34-year-old male patient with metabolic alkalosis. After X-ray diffractometry and infrared analysis of the stone, proteomic analysis was carried out. The resulting mass spectra were evaluated with protein search software, and matrix proteins were identified. X-ray diffraction and infrared analysis confirmed that the stone contained calcium carbonate and calcium oxalate dihydrate. Of the identified 53 proteins, 24 have not been previously reported from calcium oxalate- or calcium phosphate-containing stones. The protease inhibitors and several proteins related to cell adhesion or the cytoskeleton were identified for the first time. We analyzed in detail a rare urinary stone composed of calcium carbonate and calcium oxalate dihydrate. Considering the formation of a calcium carbonate stone, the new identified proteins should play an important role on the urolithiasis process in alkaline condition.

  13. Leaf calcium oxalate crystal structure and its role in defense against a chewing insect in Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Crystals of calcium oxalate are common in plants and widely distributed among many plant families. These hard and largely insoluble crystals take on many shapes and sizes depending on the tissue and species. In Medicago truncatula, calcium oxalate crystals are abundant in leaves and accumulate in sh...

  14. Calcium oxalate crystals and oxalate induce an epithelial-to-mesenchymal transition in the proximal tubular epithelial cells: Contribution to oxalate kidney injury

    PubMed Central

    Convento, Marcia Bastos; Pessoa, Edson Andrade; Cruz, Edgar; da Glória, Maria Aparecida; Schor, Nestor; Borges, Fernanda Teixeira

    2017-01-01

    TGF-β1 is the main mediator of epithelial-to-mesenchymal transition (EMT). Hyperoxaluria induces crystalluria, interstitial fibrosis, and progressive renal failure. This study analyzed whether hyperoxaluria is associated with TGF-β1 production and kidney fibrosis in mice and if oxalate or calcium oxalate (CaOx) could induce EMT in proximal tubule cells (HK2) and therefore contribute to the fibrotic process. Hyperoxaluria was induced by adding hydroxyproline and ethylene glycol to the mice’s drinking water for up to 60 days. Renal function and oxalate and urinary crystals were evaluated. Kidney collagen production and TGF-β1 expression were assessed. EMT was analyzed in vitro according to TGF-β1 production, phenotypic characterization, invasion, cell migration, gene and protein expression of epithelial and mesenchymal markers. Hyperoxaluric mice showed a decrease in renal function and an increase in CaOx crystals and Ox urinary excretion. The deposition of collagen in the renal interstitium was observed. HK2 cells stimulated with Ox and CaOx exhibited a decreased expression of epithelial as well as increased expression mesenchymal markers; these cells presented mesenchymal phenotypic changes, migration, invasiveness capability and TGF-β1 production, characterizing EMT. Treatment with BMP-7 or its overexpression in HK2 cells was effective at preventing it. This mechanism may contribute to the fibrosis observed in hyperoxaluria. PMID:28387228

  15. [Calcium oxalate stones and hyperoxaluria secondary to treatment with pyridoxilate].

    PubMed

    Wolf, C; Maistre-Charransol, G; Barthélémy, C; Thomas, E; Thomas, J; Arvis, G; Steg, A

    1985-01-01

    Pyridoxilate is a salt formed from glyoxylic acid and pyridoxine. It has been used therapeutically as an antianoxic drug in the treatment of various arterial complaints. Its use is based theoretically on its ability to block the conversion of glyoxylic acid into oxalic acid. The following cases suggest, however, that pyridoxilate can cause stones. Intraperitoneal injection of glyoxylate in doses of 130 mg/kg will cause oxalate stones in rats. The same effect results from injection of 427 mg/kg pyridoxilate (i.e. an equivalent dose of glyoxylate). In human subjects, intravenous injection of 200 mg of pyridoxilate results in a fourfold increase in the urinary oxalic acid content in the two hours following the injection. Thirteen cases of chronic progressive oxalate stone disease have recently been reported in patients receiving a prolonged course of pyridoxilate at 450 to 600 mg daily. Eight of these patients had no previous history of lithiasis. Oxaluria levels of 80 to 100 mg daily are observed in all cases of lithiasis in patients receiving pyridoxilate. The levels fell after cessation of the pyridoxilate treatment, and reverted to normal (30 mg/24 hours) in all but three patients. These three patients maintained levels of close to 50 mg and all three had a previous history of urolithiasis.

  16. Modulation of calcium oxalate monohydrate crystallization by citrate through selective binding to atomic steps

    SciTech Connect

    Qiu, S R; Wierzbicki, A; Salter, E A; Zepeda, S; Orme, C A; Hoyer, J R; Nancollas, G H; Cody, A M; De Yoreo, J J

    2004-10-19

    The majority of human kidney stones are composed primarily of calcium oxalate monohydrate (COM) crystals. Thus, determining the molecular mechanisms by which urinary constituents modulate calcium oxalate crystallization is crucial for understanding and controlling urolithiassis in humans. A comprehensive molecular-scale view of COM shape modification by citrate, a common urinary constituent, obtained through a combination of in situ atomic force microscopy (AFM) and molecular modeling is now presented. We show that citrate strongly influences the growth morphology and kinetics on the (-101) face but has much lower effect on the (010) face. Moreover, binding energy calculations show that the strength of the citrate-COM interaction is much greater at steps than on terraces and is highly step-specific. The maximum binding energy, -166.5 kJ {center_dot} mol{sup -1}, occurs for the [101] step on the (-101) face. In contrast, the value is only -56.9 kJ {center_dot} mol-1 for the [012] step on the (010) face. The binding energies on the (-101) and (010) terraces are also much smaller, -65.4 and -48.9 kJ {center_dot} mol{sup -1} respectively. All other binding energies lie between these extremes. This high selectivity leads to preferential binding of citrate to the acute [101] atomic steps on the (-101) face. The strong citrate-step interactions on this face leads to pinning of all steps, but the anisotropy in interaction strength results in anisotropic reductions in step kinetics. These anisotropic changes in step kinetics are, in turn, responsible for changes in the shape of macroscopic COM crystals. Thus, the molecular scale growth morphology and the bulk crystal habit in the presence of citrate are similar, and the predictions of molecular simulations are fully consistent with the experimental observations.

  17. Influence of magnesium on the absorption and excretion of calcium and oxalate ions.

    PubMed

    Berg, W; Bothor, C; Pirlich, W; Janitzky, V

    1986-01-01

    In two test series additional oxalic acid excretion in urine was induced in healthy test persons by administering a spinach diet. This additional excretion could be markedly reduced by magnesium administration. Calcium and citrate excretions are largely unaffected by magnesium administration. Magnesium excretions, however, are clearly increased. The calcium oxalate crystallization rates in the 5-or 7-hour urines reveal a behavior parallel to that of the oxalic acid excretion profile. In the control urines, the crystal picture is characterized by numerous medium-sized whewellite crystals. In contrast, in the test series weddellite crystals are reduced in size and frequency after magnesium administration. New aspects of magnesium effects must be discussed; above all the possible absorption changes resulting from gastrointestinal diseases.

  18. Comparison of the x-ray attenuation properties of breast calcifications, aluminium, hydroxyapatite and calcium oxalate

    NASA Astrophysics Data System (ADS)

    Warren, L. M.; Mackenzie, A.; Dance, D. R.; Young, K. C.

    2013-04-01

    Aluminium is often used as a substitute material for calcifications in phantom measurements in mammography. Additionally, calcium oxalate, hydroxyapatite and aluminium are used in simulation studies. This assumes that these materials have similar attenuation properties to calcification, and this assumption is examined in this work. Sliced mastectomy samples containing calcification were imaged at ×5 magnification using a digital specimen cabinet. Images of the individual calcifications were extracted, and the diameter and contrast of each calculated. The thicknesses of aluminium required to achieve the same contrast as each calcification when imaged under the same conditions were calculated using measurements of the contrast of aluminium foils. As hydroxyapatite and calcium oxalate are also used to simulate calcifications, the equivalent aluminium thicknesses of these materials were also calculated using tabulated attenuation coefficients. On average the equivalent aluminium thickness was 0.85 times the calcification diameter. For calcium oxalate and hydroxyapatite, the equivalent aluminium thicknesses were 1.01 and 2.19 times the thickness of these materials respectively. Aluminium and calcium oxalate are suitable substitute materials for calcifications. Hydroxyapatite is much more attenuating than the calcifications and aluminium. Using solid hydroxyapatite as a substitute for calcification of the same size would lead to excessive contrast in the mammographic image.

  19. Morphological conversion of calcium oxalate crystals into stones is regulated by osteopontin in mouse kidney.

    PubMed

    Okada, Atsushi; Nomura, Shintaro; Saeki, Yukihiko; Higashibata, Yuji; Hamamoto, Shuzo; Hirose, Masahito; Itoh, Yasunori; Yasui, Takahiro; Tozawa, Keiichi; Kohri, Kenjiro

    2008-10-01

    An important process in kidney stone formation is the conversion of retentive crystals in renal tubules to concrete stones. Osteopontin (OPN) is the major component of the kidney calcium-containing stone matrix. In this study, we estimated OPN function in early morphological changes of calcium oxalate crystals using OPN knockout mice: 100 mg/kg glyoxylate was intra-abdominally injected into wildtype mice (WT) and OPN knockout mice (KO) for a week, and 24-h urine oxalate excretion showed no significant difference between WT and KO. Kidney crystal depositions were clearly detected by Pizzolato staining but not by von Kossa staining in both genotypes, and the number of crystals in KO was significantly fewer than in WT. Morphological observation by polarized light optical microphotography and scanning electron microphotography (SEM) showed large flower-shaped crystals growing in renal tubules in WT and small and uniform crystals in KO. X-ray diffraction detected the crystal components as calcium oxalate monohydrate in both genotypes. Immunohistochemical staining of OPN showed that the WT crystals contained OPN protein but not KO crystals. We concluded that OPN plays a crucial role in the morphological conversion of calcium oxalate crystals to stones in mouse kidneys.

  20. Physical characteristics of Medicago truncatula calcium oxalate crystals determine their effectiveness in insect defense

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant structural traits can act as defense against herbivorous insects, causing them to avoid feeding on a given plant or tissue. Mineral crystals of calcium oxalate in leaves of Medicago truncatula Gaertn. have previously been shown to be effective deterrents of lepidopteran insect feeding. They ar...

  1. Structural and chemical insect defenses in calcium oxalate defective mutants of Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant structures can act as defense against herbivorous insects, causing them to avoid feeding on a given plant or tissue. Mineral crystals of calcium oxalate in leaves of Medicago truncatula Gaertn. are effective deterrents of lepidopteran feeding, and they inhibit conversion of leaves into insect ...

  2. Characterization of calcium oxalate defective (cod) 6 mutant from Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Many plants invest a considerable amount of resources and energy into the formation of calcium oxalate crystals. A number of roles for crystal formation in plant growth and development have been assigned based on their prevalence, spatial distribution, and variety of crystal shapes. These assigned...

  3. Comparison of the x-ray attenuation properties of breast calcifications, aluminium, hydroxyapatite and calcium oxalate.

    PubMed

    Warren, L M; Mackenzie, A; Dance, D R; Young, K C

    2013-04-07

    Aluminium is often used as a substitute material for calcifications in phantom measurements in mammography. Additionally, calcium oxalate, hydroxyapatite and aluminium are used in simulation studies. This assumes that these materials have similar attenuation properties to calcification, and this assumption is examined in this work. Sliced mastectomy samples containing calcification were imaged at ×5 magnification using a digital specimen cabinet. Images of the individual calcifications were extracted, and the diameter and contrast of each calculated. The thicknesses of aluminium required to achieve the same contrast as each calcification when imaged under the same conditions were calculated using measurements of the contrast of aluminium foils. As hydroxyapatite and calcium oxalate are also used to simulate calcifications, the equivalent aluminium thicknesses of these materials were also calculated using tabulated attenuation coefficients. On average the equivalent aluminium thickness was 0.85 times the calcification diameter. For calcium oxalate and hydroxyapatite, the equivalent aluminium thicknesses were 1.01 and 2.19 times the thickness of these materials respectively. Aluminium and calcium oxalate are suitable substitute materials for calcifications. Hydroxyapatite is much more attenuating than the calcifications and aluminium. Using solid hydroxyapatite as a substitute for calcification of the same size would lead to excessive contrast in the mammographic image.

  4. A study about some phosphate derivatives as inhibitors of calcium oxalate crystal growth

    NASA Astrophysics Data System (ADS)

    Grases, F.; March, P.

    1989-08-01

    The kinetic of crystal growth of calcium oxalate monohydrate seed crystals were investigated potentiometrically in the presence of several phosphate derivatives, D-fructose-1,6-diphosphate, pyrophosphate, methylene diphosphonate and phytate, and it was found that in some cases they strongly inhibited crystal growth. The inhibitory action of the different substances assayed was comparatively evaluated.

  5. An Oxalyl-CoA Dependent Pathway of Oxalate Catabolism Plays a Role in Regulating Calcium Oxalate Crystal Accumulation and Defending against Oxalate-Secreting Phytopathogens in Medicago truncatula

    PubMed Central

    Foster, Justin; Luo, Bin; Nakata, Paul A.

    2016-01-01

    Considering the widespread occurrence of oxalate in nature and its broad impact on a host of organisms, it is surprising that so little is known about the turnover of this important acid. In plants, oxalate oxidase is the most well studied enzyme capable of degrading oxalate, but not all plants possess this activity. Recently, an Acyl Activating Enzyme 3 (AAE3), encoding an oxalyl-CoA synthetase, was identified in Arabidopsis. AAE3 has been proposed to catalyze the first step in an alternative pathway of oxalate degradation. Whether this enzyme and proposed pathway is important to other plants is unknown. Here, we identify the Medicago truncatula AAE3 (MtAAE3) and show that it encodes an oxalyl-CoA synthetase activity exhibiting high activity against oxalate with a Km = 81 ± 9 μM and Vmax = 19 ± 0.9 μmoles min-1mg protein-1. GFP-MtAAE3 localization suggested that this enzyme functions within the cytosol of the cell. Mtaae3 knock-down line showed a reduction in its ability to degrade oxalate into CO2. This reduction in the capacity to degrade oxalate resulted in the accumulation of druse crystals of calcium oxalate in the Mtaae3 knock-down line and an increased susceptibility to oxalate-secreting phytopathogens such as Sclerotinia sclerotiorum. Taken together, these results suggest that AAE3 dependent turnover of oxalate is important to different plants and functions in the regulation of tissue calcium oxalate crystal accumulation and in defense against oxalate-secreting phytopathogens. PMID:26900946

  6. Calcium oxalate syntheses in a solution containing glucose by the atmospheric pressure plasma irradiation

    NASA Astrophysics Data System (ADS)

    Kurake, Naoyuki; Tanaka, Hiromasa; Ishikawa, Kenji; Nakamura, Kae; Kajiyama, Hiroaki; Kikkawa, Fumitaka; Mizuno, Masaaki; Yamanishi, Yoko; Hori, Masaru

    2016-09-01

    The non-equilibrium atmospheric pressure plasma (NEAPP) has been attracted attention because of its characteristic high reactivity even in a low temperature so that various phenomena by the NEAPP such as a sterilization, growth promotion and so forth have been reported around the world. Previously, we reported the NEAPP irradiation generated the calcium oxalate crystals in the medium, which contains 31 kinds of organics and inorganics. The Dulbecco's Modified Eagle Medium (DMEM) which was used in previous study is composed of no oxalate. Interestingly, not only crystallization but also synthesis of the oxalate was occurred by the NEAPP irradiation. Also the crystallization details were analyzed with the X-ray diffraction (XRD). In this study, we have clarified the mechanism on the crystallization due that D-glucose, calcium ion and bicarbonate ions are minimum essential components. The oxalate synthesis was proved by the gas chromatography and mass spectrometer (GC-MS). Finally, we conclude that a supersaturation of oxalic acid synthesized in those 3 species by the NEAPP.

  7. Elemental Content of Calcium Oxalate Stones from a Canine Model of Urinary Stone Disease

    PubMed Central

    Killilea, David W.; Westropp, Jodi L.; Shiraki, Ryoji; Mellema, Matthew; Larsen, Jennifer; Kahn, Arnold J.; Kapahi, Pankaj; Chi, Thomas; Stoller, Marshall L.

    2015-01-01

    One of the most common types of urinary stones formed in humans and some other mammals is composed of calcium oxalate in ordered hydrated crystals. Many studies have reported a range of metals other than calcium in human stones, but few have looked at stones from animal models such as the dog. Therefore, we determined the elemental profile of canine calcium oxalate urinary stones and compared it to reported values from human stones. The content of 19 elements spanning 7-orders of magnitude was quantified in calcium oxalate stones from 53 dogs. The elemental profile of the canine stones was highly overlapping with human stones, indicating similar inorganic composition. Correlation and cluster analysis was then performed on the elemental profile from canine stones to evaluate associations between the elements and test for potential subgrouping based on elemental content. No correlations were observed with the most abundant metal calcium. However, magnesium and sulfur content correlated with the mineral hydration form, while phosphorous and zinc content correlated with the neuter status of the dog. Inter-elemental correlation analysis indicated strong associations between barium, phosphorous, and zinc content. Additionally, cluster analysis revealed subgroups within the stones that were also based primarily on barium, phosphorous, and zinc. These data support the use of the dog as a model to study the effects of trace metal homeostasis in urinary stone disease. PMID:26066810

  8. Isoelectric focusing of Tamm-Horsfall glycoproteins: a simple tool for recognizing recurrent calcium oxalate renal stone formers.

    PubMed

    Schnierle, P; Hering, F; Seiler, H

    1996-01-01

    Tamm-Horsfall glycoproteins (THPs) from healthy probands and a majority of recurrent calcium oxalate renal stone formers reveal different physicochemical properties when analyzed using isoelectric focusing (IEF). The pI values of THPs from healthy probands are approximately 3.5 while THPs from recurrent renal stone formers have pI values of between 4.5 and 6. The two groups of THPs exhibit completely different protein patterns. The differences in IEF analysis allow differentiation between THPs from healthy probands and recurrent calcium oxalate stone formers and may possibly be used as a simple diagnostic method for the recognition of recurrent calcium oxalate renal stone formers.

  9. Reinjury risk of nano-calcium oxalate monohydrate and calcium oxalate dihydrate crystals on injured renal epithelial cells: aggravation of crystal adhesion and aggregation

    PubMed Central

    Gan, Qiong-Zhi; Sun, Xin-Yuan; Bhadja, Poonam; Yao, Xiu-Qiong; Ouyang, Jian-Ming

    2016-01-01

    Background Renal epithelial cell injury facilitates crystal adhesion to cell surface and serves as a key step in renal stone formation. However, the effects of cell injury on the adhesion of nano-calcium oxalate crystals and the nano-crystal-induced reinjury risk of injured cells remain unclear. Methods African green monkey renal epithelial (Vero) cells were injured with H2O2 to establish a cell injury model. Cell viability, superoxide dismutase (SOD) activity, malonaldehyde (MDA) content, propidium iodide staining, hematoxylin–eosin staining, reactive oxygen species production, and mitochondrial membrane potential (Δψm) were determined to examine cell injury during adhesion. Changes in the surface structure of H2O2-injured cells were assessed through atomic force microscopy. The altered expression of hyaluronan during adhesion was examined through laser scanning confocal microscopy. The adhesion of nano-calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) crystals to Vero cells was observed through scanning electron microscopy. Nano-COM and COD binding was quantitatively determined through inductively coupled plasma emission spectrometry. Results The expression of hyaluronan on the cell surface was increased during wound healing because of Vero cell injury. The structure and function of the cell membrane were also altered by cell injury; thus, nano-crystal adhesion occurred. The ability of nano-COM to adhere to the injured Vero cells was higher than that of nano-COD crystals. The cell viability, SOD activity, and Δψm decreased when nano-crystals attached to the cell surface. By contrast, the MDA content, reactive oxygen species production, and cell death rate increased. Conclusion Cell injury contributes to crystal adhesion to Vero cell surface. The attached nano-COM and COD crystals can aggravate Vero cell injury. As a consequence, crystal adhesion and aggregation are enhanced. These findings provide further insights into kidney stone

  10. Strain differences in urinary factors that promote calcium oxalate crystal formation in the kidneys of ethylene glycol-treated rats.

    PubMed

    Li, Yan; McMartin, Kenneth E

    2009-05-01

    Ethylene glycol (EG)-induced hyperoxaluria is the most commonly employed experimental regimen as an animal model of calcium oxalate (CaOx) stone formation. The variant sensitivity to CaOx among different rat strains has not been fully explored, although the Wistar rat is known to accumulate more CaOx in kidney tissue after low-dose EG exposure than in the Fischer 344 (F344) rats. Supersaturation of CaOx in tubular fluid contributes to the amount of CaOx crystal formation in the kidney. We hypothesized that the urinary supersaturation of CaOx in Wistar rats is higher than that of F344 rats, thereby allowing for greater CaOx crystal deposition in the Wistar rat. Age-matched male Wistar and F344 rats were treated with 0.75% EG or drinking water for 8 wk. Twenty-four-hour urine was collected at 0, 2, 4, 6, and 8 wk for analysis of key electrolytes to calculate the CaOx supersaturation. Plasma oxalate level was also measured. Our data confirmed the different sensitivity to renal toxicity from EG between the two rat strains (Wistar > F344). After EG treatment, the plasma oxalate level and urine oxalate excretion were markedly greater in the Wistar rats than in the F344 rats, while urine calcium was slightly decreased in Wistars. Thus, the CaOx supersaturation in urine of Wistar rats was higher, which led to a greater crystal deposition in kidney in Wistar rats. These studies suggest that during EG treatment, changes in urine electrolytes and in CaOx supersaturation occur to a greater extent in the Wistar rat, in agreement with its greater sensitivity to EG toxicity.

  11. Increased 10-year cardiovascular disease and mortality risk scores in asymptomatic patients with calcium oxalate urolithiasis.

    PubMed

    Aydin, Hasan; Yencilek, Faruk; Erihan, Ismet Bilger; Okan, Binnur; Sarica, Kemal

    2011-12-01

    Both the prevalence of cardiovascular risk factors and event rate are increased in patients with urolithiasis. Screening is recommended to all patients who have high cardiovascular risk. The aim of this study was to document 10-year risk of cardiovascular disease and mortality in asymptomatic patients with urolithiasis. Consecutive 200 patients with calcium oxalate urolithiasis were compared with 200 age- and sex-matched healthy controls. Ten-year cardiovascular disease risk was calculated with the Framingham Risk Score and mortality risk with SCORE risk score. Calcium, oxalate, and citrate excretion were studied as urinary stone risk factors. The results indicate that patients with urolithiasis had higher total cholesterol (p < 0.0001), lower HDL-cholesterol (p < 0.0001), and higher systolic blood pressure (p < 0.0001) and hsCRP (p < 0.0001) compared with controls. Patients with urolithiasis had a higher Framingham Risk Scores [OR 8.36 (95% CI 3.81-18.65), p = 0.0001] and SCORE risk score [OR 3.02 (95% CI 1.30-7.02), p = 0.0006] compared with controls. The Framingham and SCORE risk score were significantly correlated with urinary calcium (p = 0.0001, r = 0.460, and p = 0.005, r = 0.223, respectively) and oxalate excretion (p = 0.0001, r = 0.516, p = 0.001, r = 0.290, respectively). In multiple linear regression analysis, urinary calcium and oxalate excretion, age, sex, total cholesterol, HDL-cholesterol, hsCRP and smoking were the independent predictors of 10-year cardiovascular disease risk and urinary calcium and oxalate excretion, age, sex, total cholesterol, fasting blood glucose for 10-year cardiovascular mortality. In conclusion, patients with calcium oxalate urolithiasis carry high risk of cardiovascular disease and mortality. All patients should be screened at the initial diagnosis of urolithiasis for the risk factors.

  12. Calcium oxalate crystallization index (COCI): an alternative method for distinguishing nephrolithiasis patients from healthy individuals.

    PubMed

    Yang, Bowei; Dissayabutra, Thasinas; Ungjaroenwathana, Wattanachai; Tosukhowong, Piyaratana; Srisa-Art, Monpichar; Supaprom, Thavorn; Insin, Numpon; Boonla, Chanchai

    2014-01-01

    Urinary supersaturation triggers lithogenic crystal formation. We developed an alternative test, designated calcium oxalate crystallization index (COCI), to distinguish nephrolithiasis patients from healthy individuals based on their urinary crystallization capability. The effect of urine volume, oxalate, phosphate, citrate, potassium, and sodium on COCI values was investigated. COCI values were determined in 24-hr urine obtained from nephrolithiasis patients (n=72) and matched healthy controls (n=71). Increases in urine oxalate and phosphate and decreases in urine volume and citrate resulted in significantly increased COCI values. The urinary COCI in nephrolithiasis patients was significantly higher than that in healthy individuals. Two healthy subjects who had elevated COCI values were found to have asymptomatic kidney calculi. The receiver operating characteristic analysis showed an area under the curve of the urinary COCI test of 0.9499 (95%CI: 0.9131-0.9868) for distinguishing between nephrolithiasis and healthy subjects. At the cutoff of 165 mg oxalate equivalence/day, the urinary COCI test provided sensitivity, specificity, and accuracy amounts of 83.33%, 97.18%, and 90.21%, respectively. Urinary COCI values were primarily dependent on urine volume, oxalate, and phosphate. The test provided high sensitivity and specificity for clinically discriminating nephrolithiasis patients from healthy controls. It might be used to detect individuals with asymptomatic kidney calculi.

  13. Effect of hyperprotidic diet associated or not with hypercalcic diet on calcium oxalate stone formation in rat.

    PubMed

    Sakly, R; Bardaoui, M; Neffati, F; Moussa, A; Zakhama, A; Najjar, M F; Hammami, M

    2005-01-01

    The aim of this study was to determine whether protein, administered alone or simultaneously with a hypercalcic diet, was able to aggravate calcium oxalate stone formation in rats. Thirty-two male Wistar rats were randomly divided into four groups of 8 rats each and assigned a calcium oxalate lithogenic diet added to their drinking water for 3 weeks. One group, used as reference, received a standard diet prepared in our laboratory. The second was assigned the same diet but supplemented with 7.5 g animal proteins/100 g diet. The third received a diet containing 500 mg calcium more than the standard group. The diet given to the last group was supplemented with calcium and protein at the same doses indicated previously. One day before the end of treatment, each animal was placed in a metabolic cage to collect 24-hour urine samples and determine urinary creatinine, urea, calcium, magnesium, phosphate, uric acid, citric acid and oxalate levels. Immediately thereafter, aortic blood was collected to determine the same parameters as in urine. The kidneys were also removed to determine calcium oxalate deposits. Our results showed an increased 24-hour urinary excretion of calcium, oxalate and uric acid and decreased urinary citric acid excretion only in groups that received protein supplementation. At the same time, calcium oxalate deposits were found significantly higher in hyperprotidic diets than reference or calcium-supplemented groups. According to these findings, glomerular filtration, fractional excretion of urea and reabsorption of water, calcium and magnesium were found significantly lower in hyperprotidic diets compared to other groups. These results demonstrate that proteins could seriously aggravate calcium oxalate stones and cause renal disturbances.

  14. Alarm Photosynthesis: Calcium Oxalate Crystals as an Internal CO2 Source in Plants.

    PubMed

    Tooulakou, Georgia; Giannopoulos, Andreas; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Dotsika, Elissavet; Orkoula, Malvina G; Kontoyannis, Christos G; Fasseas, Costas; Liakopoulos, Georgios; Klapa, Maria I; Karabourniotis, George

    2016-08-01

    Calcium oxalate crystals are widespread among animals and plants. In land plants, crystals often reach high amounts, up to 80% of dry biomass. They are formed within specific cells, and their accumulation constitutes a normal activity rather than a pathological symptom, as occurs in animals. Despite their ubiquity, our knowledge on the formation and the possible role(s) of these crystals remains limited. We show that the mesophyll crystals of pigweed (Amaranthus hybridus) exhibit diurnal volume changes with a gradual decrease during daytime and a total recovery during the night. Moreover, stable carbon isotope composition indicated that crystals are of nonatmospheric origin. Stomatal closure (under drought conditions or exogenous application of abscisic acid) was accompanied by crystal decomposition and by increased activity of oxalate oxidase that converts oxalate into CO2 Similar results were also observed under drought stress in Dianthus chinensis, Pelargonium peltatum, and Portulacaria afra Moreover, in A. hybridus, despite closed stomata, the leaf metabolic profiles combined with chlorophyll fluorescence measurements indicated active photosynthetic metabolism. In combination, calcium oxalate crystals in leaves can act as a biochemical reservoir that collects nonatmospheric carbon, mainly during the night. During the day, crystal degradation provides subsidiary carbon for photosynthetic assimilation, especially under drought conditions. This new photosynthetic path, with the suggested name "alarm photosynthesis," seems to provide a number of adaptive advantages, such as water economy, limitation of carbon losses to the atmosphere, and a lower risk of photoinhibition, roles that justify its vast presence in plants.

  15. Synthesis of calcium oxalate crystals in culture medium irradiated with non-equilibrium atmospheric-pressure plasma

    NASA Astrophysics Data System (ADS)

    Kurake, Naoyuki; Tanaka, Hiromasa; Ishikawa, Kenji; Nakamura, Kae; Kajiyama, Hiroaki; Kikkawa, Fumitaka; Mizuno, Masaaki; Yamanishi, Yoko; Hori, Masaru

    2016-09-01

    Octahedral particulates several tens of microns in size were synthesized in a culture medium irradiated through contact with a plume of non-equilibrium atmospheric-pressure plasma (NEAPP). The particulates were identified in the crystalline phase as calcium oxalate dihydrate (COD). The original medium contained constituents such as NaCl, d-glucose, CaCl2, and NaHCO3 but not oxalate or oxalic acid. The oxalate was clearly synthesized and crystallized in the medium as thermodynamically unstable COD crystals after the NEAPP irradiation.

  16. Reevaluation of the plant "gemstones": Calcium oxalate crystals sustain photosynthesis under drought conditions.

    PubMed

    Tooulakou, Georgia; Giannopoulos, Andreas; Nikolopoulos, Dimosthenis; Bresta, Panagiota; Dotsika, Elissavet; Orkoula, Malvina G; Kontoyannis, Christos G; Fasseas, Costas; Liakopoulos, Georgios; Klapa, Maria I; Karabourniotis, George

    2016-09-01

    Land plants face the perpetual dilemma of using atmospheric carbon dioxide for photosynthesis and losing water vapors, or saving water and reducing photosynthesis and thus growth. The reason behind this dilemma is that this simultaneous exchange of gases is accomplished through the same minute pores on leaf surfaces, called stomata. In a recent study we provided evidence that pigweed, an aggressive weed, attenuates this problem exploiting large crystals of calcium oxalate as dynamic carbon pools. This plant is able to photosynthesize even under drought conditions, when stomata are closed and water losses are limited, using carbon dioxide from crystal decomposition instead from the atmosphere. Abscisic acid, an alarm signal that causes stomatal closure seems to be implicated in this function and for this reason we named this path "alarm photosynthesis." The so-far "enigmatic," but highly conserved and widespread among plant species calcium oxalate crystals seem to play a crucial role in the survival of plants.

  17. Does aridity influence the morphology, distribution and accumulation of calcium oxalate crystals in Acacia (Leguminosae: Mimosoideae)?

    PubMed

    Brown, Sharon L; Warwick, Nigel W M; Prychid, Christina J

    2013-12-01

    Calcium oxalate (CaOx) crystals are a common natural feature of many plant families, including the Leguminosae. The functional role of crystals and the mechanisms that underlie their deposition remain largely unresolved. In several species, the seasonal deposition of crystals has been observed. To gain insight into the effects of rainfall on crystal formation, the morphology, distribution and accumulation of calcium oxalate crystals in phyllodes of the leguminous Acacia sect. Juliflorae (Benth.) C. Moore & Betche from four climate zones along an aridity gradient, was investigated. The shapes of crystals, which include rare Rosanoffian morphologies, were constant between species from different climate zones, implying that morphology was not affected by rainfall. The distribution and accumulation of CaOx crystals, however, did appear to be climate-related. Distribution was primarily governed by vein density, an architectural trait which has evolved in higher plants in response to increasing aridity. Furthermore, crystals were more abundant in acacias from low rainfall areas, and in phyllodes containing high concentrations of calcium, suggesting that both aridity and soil calcium levels play important roles in the precipitation of CaOx. As crystal formation appears to be calcium-induced, we propose that CaOx crystals in Acacia most likely function in bulk calcium regulation.

  18. Kinetics of calcium oxalate crystal formation in urine.

    PubMed

    Laube, Norbert; Klein, Florian; Bernsmann, Falk

    2017-04-01

    It is routinely observed that persons with increased urinary stone risk factors do not necessarily form uroliths. Furthermore, stone formers can present with urinalyses that do not reflect the clinical picture. We explain this discrepancy by differences in crystallization kinetics. In 1162 urines, crystallization of Ca-oxalate was induced according to the BONN-Risk-Index (BRI) method. The urine's relative light transmissivity (RLT) was recorded from 100 % at start of titration to 95 % due to nuclei formation and crystal growth. From the RLT changes, a measure of the thermodynamic inhibition threshold of crystal formation (BRI) and of crystal growth kinetics is derived ("turbidity slope" after crystallization onset). On average, subjects presenting with a low inhibition threshold, i.e., high BRI, also present significantly higher crystal growth rates compared with subjects in lower BRI classes. Only subjects in the highest BRI class show a lower growth rate than expected, probably due to a depletion of supersaturation by massive initial nucleation. With increasing thermodynamic risk of crystal formation (i.e., increasing BRI) due to an imbalance between inhibitors and promoters of crystal formation, an increase in the imbalance between inhibitors and promoters of crystal growth (i.e., increasing growth rate) is observed. Both lead to an increased urolith formation risk. Healthy subjects with increased BRI are an exception to this trend: their urine is thermodynamically prone to form stones, but they show a kinetic inhibition preventing nuclei from significant growth.

  19. Antilithiatic Activity of phlorotannin rich extract of Sarghassum Wightii on Calcium Oxalate Urolithiais – In Vitro and In Vivo Evaluation

    PubMed Central

    Sujatha, D.; Singh, Kiranpal; Vohra, Mursalin; Kumar, K. Vijay; Sunitha, S.

    2015-01-01

    ABSTRACT Purpose: Urolithiasis is a common urological disorder responsible for serious human affliction and cost to the society with a high recurrence rate. The aim of the present study was to systematically evaluate the phlorotannin rich extract of Sargassum wightii using suitable in vitro and in vivo models to provide scientific evidence for its antilithiatic activity. Materials and Methods: To explore the effect of Sargassum wightii on calcium oxalate crystallization, in vitro assays like crystal nucleation, aggregation and crystal growth were performed. Calcium oxalate urolithiasis was induced in male Sprague dawley rats using a combination of gentamicin and calculi producing diet (5% ammonium oxalate and rat pellet feed). The biochemical parameters like calcium, oxalate, magnesium, phosphate, sodium and potassium were evaluated in urine, serum and kidney homogenates. Histopathological studies were also done to confirm the biochemical findings. Results: The yield of Sargassum wightii extract was found to be 74.5 gm/kg and confirmed by quantitative analysis. In vitro experiments with Sargassum wightii showed concentration dependent inhibition of calcium oxalate nucleation, aggregation and growth supported by SEM analysis. In the in vivo model, Sargassum wightii reduced both calcium and oxalate supersaturation in urine, serum and deposition in the kidney. The biochemical results were supported by histopathological studies. Conclusion: The findings of the present study suggest that Sargassum wightii has the ability to prevent nucleation, aggregation and growth of calcium oxalate crystals. Sargassum wightii has better preventive effect on calcium oxalate stone formation indicating its strong potential to develop as a therapeutic option to prevent recurrence of urolithiasis. PMID:26200544

  20. Oxalate secretion by ectomycorrhizal Paxillus involutus is mineral-specific and controls calcium weathering from minerals

    PubMed Central

    Schmalenberger, A.; Duran, A. L.; Bray, A. W.; Bridge, J.; Bonneville, S.; Benning, L. G.; Romero-Gonzalez, M. E.; Leake, J. R.; Banwart, S. A.

    2015-01-01

    Trees and their associated rhizosphere organisms play a major role in mineral weathering driving calcium fluxes from the continents to the oceans that ultimately control long-term atmospheric CO2 and climate through the geochemical carbon cycle. Photosynthate allocation to tree roots and their mycorrhizal fungi is hypothesized to fuel the active secretion of protons and organic chelators that enhance calcium dissolution at fungal-mineral interfaces. This was tested using 14CO2 supplied to shoots of Pinus sylvestris ectomycorrhizal with the widespread fungus Paxillus involutus in monoxenic microcosms, revealing preferential allocation by the fungus of plant photoassimilate to weather grains of limestone and silicates each with a combined calcium and magnesium content of over 10 wt.%. Hyphae had acidic surfaces and linear accumulation of weathered calcium with secreted oxalate, increasing significantly in sequence: quartz, granite < basalt, olivine, limestone < gabbro. These findings confirmed the role of mineral-specific oxalate exudation in ectomycorrhizal weathering to dissolve calcium bearing minerals, thus contributing to the geochemical carbon cycle. PMID:26197714

  1. Oxalate secretion by ectomycorrhizal Paxillus involutus is mineral-specific and controls calcium weathering from minerals.

    PubMed

    Schmalenberger, A; Duran, A L; Bray, A W; Bridge, J; Bonneville, S; Benning, L G; Romero-Gonzalez, M E; Leake, J R; Banwart, S A

    2015-07-22

    Trees and their associated rhizosphere organisms play a major role in mineral weathering driving calcium fluxes from the continents to the oceans that ultimately control long-term atmospheric CO2 and climate through the geochemical carbon cycle. Photosynthate allocation to tree roots and their mycorrhizal fungi is hypothesized to fuel the active secretion of protons and organic chelators that enhance calcium dissolution at fungal-mineral interfaces. This was tested using (14)CO2 supplied to shoots of Pinus sylvestris ectomycorrhizal with the widespread fungus Paxillus involutus in monoxenic microcosms, revealing preferential allocation by the fungus of plant photoassimilate to weather grains of limestone and silicates each with a combined calcium and magnesium content of over 10 wt.%. Hyphae had acidic surfaces and linear accumulation of weathered calcium with secreted oxalate, increasing significantly in sequence: quartz, granite < basalt, olivine, limestone < gabbro. These findings confirmed the role of mineral-specific oxalate exudation in ectomycorrhizal weathering to dissolve calcium bearing minerals, thus contributing to the geochemical carbon cycle.

  2. Oxalate secretion by ectomycorrhizal Paxillus involutus is mineral-specific and controls calcium weathering from minerals

    NASA Astrophysics Data System (ADS)

    Schmalenberger, A.; Duran, A. L.; Bray, A. W.; Bridge, J.; Bonneville, S.; Benning, L. G.; Romero-Gonzalez, M. E.; Leake, J. R.; Banwart, S. A.

    2015-07-01

    Trees and their associated rhizosphere organisms play a major role in mineral weathering driving calcium fluxes from the continents to the oceans that ultimately control long-term atmospheric CO2 and climate through the geochemical carbon cycle. Photosynthate allocation to tree roots and their mycorrhizal fungi is hypothesized to fuel the active secretion of protons and organic chelators that enhance calcium dissolution at fungal-mineral interfaces. This was tested using 14CO2 supplied to shoots of Pinus sylvestris ectomycorrhizal with the widespread fungus Paxillus involutus in monoxenic microcosms, revealing preferential allocation by the fungus of plant photoassimilate to weather grains of limestone and silicates each with a combined calcium and magnesium content of over 10 wt.%. Hyphae had acidic surfaces and linear accumulation of weathered calcium with secreted oxalate, increasing significantly in sequence: quartz, granite < basalt, olivine, limestone < gabbro. These findings confirmed the role of mineral-specific oxalate exudation in ectomycorrhizal weathering to dissolve calcium bearing minerals, thus contributing to the geochemical carbon cycle.

  3. Inhibition of calcium oxalate crystal growth in vitro by uropontin: another member of the aspartic acid-rich protein superfamily.

    PubMed Central

    Shiraga, H; Min, W; VanDusen, W J; Clayman, M D; Miner, D; Terrell, C H; Sherbotie, J R; Foreman, J W; Przysiecki, C; Neilson, E G

    1992-01-01

    The majority of human urinary stones are primarily composed of calcium salts. Although normal urine is frequently supersaturated with respect to calcium oxalate, most humans do not form stones. Inhibitors are among the multiple factors that may influence the complex process of urinary stone formation. We have isolated an inhibitor of calcium oxalate crystal growth from human urine by monoclonal antibody immunoaffinity chromatography. The N-terminal amino acid sequence and acidic amino acid content of this aspartic acid-rich protein, uropontin, are similar to those of other pontin proteins from bone, plasma, breast milk, and cells. The inhibitory effect of uropontin on calcium oxalate crystal growth in vitro supports the concept that pontins may have a regulatory role. This function would be analogous to that of other members of the aspartic acid-rich protein superfamily, which stereospecifically regulate the mineralization fronts of calcium-containing crystals. Images PMID:1729712

  4. Evaluation of urinary and serum metabolites in Asian small-clawed otters (Aonyx cinerea) with calcium oxalate urolithiasis.

    PubMed

    Petrini, K R; Lulich, J P; Treschel, L; Nachreiner, R F

    1999-03-01

    Baseline renal function data was collected during 24-hr periods of feeding and fasting from three male and three female adult Asian small-clawed otters (Aonyx cinerea) with calcium oxalate urolithiasis. Urine was analyzed for calcium, phosphorus, and oxalate, and urinalyses were performed. There was no evidence of glucosuria, which has been previously reported in Asian small-clawed otters with urolithiasis. Urinary oxalate levels were quite high when compared with those of dogs and humans without uroliths, and the ratio of urinary oxalate to calcium was close to 1:1 during periods of food consumption. There was no significant difference in urinary oxalate excretion between the fed and fasting states. Urinary calcium excretion was five times greater during feeding than during fasting. Calcium levels were higher in the otters than those reported for dogs without uroliths but were similar to those for normal humans. Water consumption and urine production were significantly higher during periods of food consumption. Serum chemistry analyses and electrolyte levels were also determined. There was no evidence of hypercalcemia. Fractional clearance of calcium and phosphorus and endogenous creatinine clearance were significantly higher during food consumption than during fasting. Parathyroid hormone levels were similar to those reported for dogs and cats. Serum 25-hydroxy-vitamin D was slightly lower in the otters than in dogs.

  5. Isolation of a crystal matrix protein associated with calcium oxalate precipitation in vacuoles of specialized cells.

    PubMed

    Li, Xingxiang; Zhang, Dianzhong; Lynch-Holm, Valerie J; Okita, Thomas W; Franceschi, Vincent R

    2003-10-01

    The formation of calcium (Ca) oxalate crystals is considered to be a high-capacity mechanism for regulating Ca in many plants. Ca oxalate precipitation is not a stochastic process, suggesting the involvement of specific biochemical and cellular mechanisms. Microautoradiography of water lettuce (Pistia stratiotes) tissue exposed to 3H-glutamate showed incorporation into developing crystals, indicating potential acidic proteins associated with the crystals. Dissolution of crystals leaves behind a crystal-shaped matrix "ghost" that is capable of precipitation of Ca oxalate in the original crystal morphology. To assess whether this matrix has a protein component, purified crystals were isolated and analyzed for internal protein. Polyacrylamide gel electrophoresis revealed the presence of one major polypeptide of about 55 kD and two minor species of 60 and 63 kD. Amino acid analysis indicates the matrix protein is relatively high in acidic amino acids, a feature consistent with its solubility in formic acid but not at neutral pH. 45Ca-binding assays demonstrated the matrix protein has a strong affinity for Ca. Immunocytochemical localization using antibody raised to the isolated protein showed that the matrix protein is specific to crystal-forming cells. Within the vacuole, the surface and internal structures of two morphologically distinct Ca oxalate crystals, raphide and druse, were labeled by the antimatrix protein serum, as were the surfaces of isolated crystals. These results demonstrate that a specific Ca-binding protein exists as an integral component of Ca oxalate crystals, which holds important implications with respect to regulation of crystal formation.

  6. Increased calcium bioavailability in mice fed genetically engineered plants lacking calcium oxalate

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the model forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 M. truncatula mutant was identified which contains identical ...

  7. Urinary saturation and risk factors for calcium oxalate stone disease based on spot and 24-hour urine specimens.

    PubMed

    Ogawa, Yoshihide; Yonou, Hiroyuki; Hokama, Sanehiro; Oda, Masami; Morozumi, Makoto; Sugaya, Kimio

    2003-09-01

    In 222 random spot urine specimens, the calcium concentration and calcium oxalate saturation [DG(CaOx)] were significantly higher among stone formers than among non-stone formers, while the citrate and creatinine-corrected citrate concentrations were lower. In 188 24-hour urine specimens, magnesium excretion was lower among stone formers than non-stone formers, while the creatinine-corrected calcium concentration and DG(CaOx) were higher. Among stone formers, there was no gender difference in the urinary concentrations of calcium, oxalate, citrate, magnesium, and DG(CaOx), but the creatinine-corrected calcium, citrate, and magnesium concentrations were higher in women, as well as 24-hour citrate excretion. The levels of calcium and oxalate have a major influence on DG(CaOx), while citrate and magnesium levels have a minor influence. DG(CaOx) was correlated with calcium and oxalate excretion, as well as with the creatinine-corrected calcium and oxalate concentrations. Approximately 5% of 24-hour urine specimens showed critical supersaturation, 80% showed metastable supersaturation, and 15% were unsaturated. Hypercalciuria or hyperoxaluria was fairly common (30% and 40%) in critically supersaturated urine, while it was less common (22.4% and 8.6%) in metastably supersaturated urine and was not detected in unsaturated urine. Hypocitraturia and/or hypomagnesiuria was more common (63.8-80%) at any saturation. The urinary calcium, oxalate, and citrate concentrations, as well as the creatinine-corrected calcium, oxalate, citrate, and magnesium concentrations and DG(CaOx), showed a significant correlation between 57 paired early morning spot urine and 24-hour urine specimens. The creatinine-corrected calcium and citrate concentrations of the early morning urine specimens were significantly correlated with the levels of calcium and citrate excretion in the paired 24-hour urine specimens. In conclusion, no parameter other than urinary saturation gives more than a vague

  8. The nucleation and growth of calcium oxalate monohydrate on self- assembled monolayers (SAMs)

    SciTech Connect

    Campbell, A.A.; Tarasevich, B.J.; Graff, G.L.; Fryxell, G.E.; Rieke, P.C.

    1992-05-01

    A physical chemical approach was used to study calcium oxalate monohydrate (COM) nucleation and growth on various organic interfaces. Self-assembling monolayers (SAMs), containing derivatized organic functional groups, were designed to mimic various amino acid residues present in both urine and stone matrix macromolecules. Derivatized surfaces include SAMs with terminal methyl, bromo, imidazole, and thiazolidine-carboxylic acid functional groups. Pronounced differences in COM deposition were observed for the various interfaces with the imidazole and thiazolidine surfaces having the greatest effect and the methyl and bromo groups having little or no nucleating potential.

  9. Production of calcium oxalate crystals by the basidiomycete Moniliophthora perniciosa, the causal agent of witches' broom disease of Cacao.

    PubMed

    Rio, Maria Carolina S do; de Oliveira, Bruno V; de Tomazella, Daniela P T; Silva, José A Fracassi da; Pereira, Gonçalo A G

    2008-04-01

    Oxalic acid has been shown as a virulence factor for some phytopathogenic fungi, removing calcium from pectin and favoring plant cell wall degradation. Recently, it was published that calcium oxalate accumulates in infected cacao tissues during the progression of Witches' Broom disease (WBD). In the present work we report that the hemibiotrophic basidiomycete Moniliophthora perniciosa, the causal agent of WBD, produces calcium oxalate crystals. These crystals were initially observed by polarized light microscopy of hyphae growing on a glass slide, apparently being secreted from the cells. The analysis was refined by Scanning electron microscopy and the compositon of the crystals was confirmed by energy-dispersive x-ray spectrometry. The production of oxalate by M. perniciosa was reinforced by the identification of a putative gene coding for oxaloacetate acetylhydrolase, which catalyzes the hydrolysis of oxaloacetate to oxalate and acetate. This gene was shown to be expressed in the biotrophic-like mycelia, which in planta occupy the intercellular middle-lamella space, a region filled with pectin. Taken together, our results suggest that oxalate production by M. perniciosa may play a role in the WBD pathogenesis mechanism.

  10. Calcium oxalate crystals: an integral component of the Sclerotinia sclerotiorum/Brassica carinata pathosystem.

    PubMed

    Uloth, Margaret B; Clode, Peta L; You, Ming Pei; Barbetti, Martin J

    2015-01-01

    Oxalic acid is an important virulence factor for disease caused by the fungal necrotrophic pathogen Sclerotinia sclerotiorum, yet calcium oxalate (CaOx) crystals have not been widely reported. B. carinata stems were infected with S. sclerotiorum and observed using light microscopy. Six hours post inoculation (hpi), CaOx crystals were evident on 46% of stem sections and by 72 hpi on 100%, demonstrating that the secretion of oxalic acid by S. sclerotiorum commences before hyphal penetration. This is the first time CaOx crystals have been reported on B. carinata infected with S. sclerotiorum. The shape of crystals varied as infection progressed. Long tetragonal rods were dominant 12 hpi (68% of crystal-containing samples), but by 72 hpi, 50% of stems displayed bipyramidal crystals, and only 23% had long rods. Scanning electron microscopy from 24 hpi revealed CaOx crystals in all samples, ranging from tiny irregular crystals (< 0.5 μm) to large (up to 40 μm) highly organized arrangements. Crystal morphology encompassed various forms, including tetragonal prisms, oval plates, crystal sand, and druses. Large conglomerates of CaOx crystals were observed in the hyphal mass 72 hpi and these are proposed as a strategy of the fungus to hold and detoxify Ca2+ions. The range of crystal morphologies suggests that S. sclerotiorum growth and infection controls the form taken by CaOx crystals.

  11. [EXPERIENCE OF USE OF BLEMAREN® IN THE TREATMENT OF PATIENTS IN URIC ACID AND CALCIUM OXALATE UROLITHIASIS].

    PubMed

    Konstantinova, O V; Yanenko, E K

    2015-01-01

    154 patients with urolithiasis were under outpatient observation for 2-8 years. Among them there were 76 women and 78 men aged 21-66 years, of which 46 patients with uric acid urolithiasis, and 88--with calcium oxalate urolithiasis. Treatment of patients was carried out systematically, depending on their condition. Indications for the application of Blemaren® included the presence of uric acid stones, uric acid and/or oxalate crystalluria. The duration of treatment was 6.1 months. The dosage of the drug varied from 6 to 18 g per day and was selected individually, depending on the purpose of the appointment of Blemaren®. Reduction of the urine pH to 6.2- 6.8-7.2 was the criterion for properly selected dose. To dissolve uric acid stones in the presence of hyperuricemia and/or hyperuricuria, Blemaren® was administered in combination with allopurinol at a dose of 0.1 g 3-4 times a day. Besides pharmacotherapy, treatment included diet therapy. It was found that the morning urine pH in urate urolithiasis is sustainable and has a range of 5.0-6.0, in 80.4% of cases--range of 5.0-5.5. In calcium oxalate urolithiasis this parameter is also stable and has a range of 5.0-6.7, in 82.9% of cases--range of 5.5-6.0. Optimal urine pH to eliminate uric acid and oxalate crystalluria in patients with uric acid and calcium oxalate urolithiasis is the interval of 6.2-6.4. It was shown that Blemaren® is a highly effective agent for treatment and prevention of uric acid and calcium oxalate crystalluria in calcium oxalate and uric acid urolithiasis. Further, its effectiveness in dissolving of uric acid stones in the absence of an infectious inflammatory process is 82.3%.

  12. Primary Hyperoxaluria Type III Gene HOGA1 (Formerly DHDPSL) as a Possible Risk Factor for Idiopathic Calcium Oxalate Urolithiasis

    PubMed Central

    Rossetti, Sandro; Belostotsky, Ruth; Cogal, Andrea G.; Herges, Regina M.; Seide, Barbara M.; Olson, Julie B.; Bergstrahl, Eric J.; Williams, Hugh J.; Haley, William E.; Frishberg, Yaacov; Milliner, Dawn S.

    2011-01-01

    Summary Background and objectives Primary hyperoxaluria types I and II (PHI and PHII) are rare monogenic causes of hyperoxaluria and calcium oxalate urolithiasis. Recently, we described type III, due to mutations in HOGA1 (formerly DHDPSL), hypothesized to cause a gain of mitochondrial 4-hydroxy-2-oxoglutarate aldolase activity, resulting in excess oxalate. Design, setting, participants, & measurements To further explore the pathophysiology of HOGA1, we screened additional non-PHI-PHII patients and performed reverse transcription PCR analysis. Postulating that HOGA1 may influence urine oxalate, we also screened 100 idiopathic calcium oxalate stone formers. Results Of 28 unrelated hyperoxaluric patients with marked hyperoxaluria not due to PHI, PHII, or any identifiable secondary cause, we identified 10 (36%) with two HOGA1 mutations (four novel, including a nonsense variant). Reverse transcription PCR of the stop codon and two common mutations showed stable expression. From the new and our previously described PHIII cohort, 25 patients were identified for study. Urine oxalate was lower and urine calcium and uric acid were higher when compared with PHI and PHII. After 7.2 years median follow-up, mean eGFR was 116 ml/min per 1.73 m2. HOGA1 heterozygosity was found in two patients with mild hyperoxaluria and in three of 100 idiopathic calcium oxalate stone formers. No HOGA1 variants were detected in 166 controls. Conclusions These findings, in the context of autosomal recessive inheritance for PHIII, support a loss-of-function mechanism for HOGA1, with potential for a dominant-negative effect. Detection of HOGA1 variants in idiopathic calcium oxalate urolithiasis also suggests HOGA1 may be a predisposing factor for this condition. PMID:21896830

  13. An Assessment of Engineered Calcium Oxalate Crystal Formation on Plant Growth and Development as a Step toward Evaluating Its Use to Enhance Plant Defense.

    PubMed

    Nakata, Paul A

    2015-01-01

    The establishment of new approaches to control chewing insects has been sought not only for direct use in reducing crop loss but also in managing resistance to the pesticides already in use. Engineered formation of calcium oxalate crystals is a potential strategy that could be developed to fulfill both these needs. As a step toward this development, this study investigates the effects of transforming a non-calcium oxalate crystal accumulating plant, Arabidopsis thaliana, into a crystal accumulating plant. Calcium oxalate crystal accumulating A. thaliana lines were generated by ectopic expression of a single bacterial gene encoding an oxalic acid biosynthetic enzyme. Biochemical and cellular studies suggested that the engineered A. thaliana lines formed crystals of calcium oxalate in a manner similar to naturally occurring crystal accumulating plants. The amount of calcium oxalate accumulated in leaves also reached levels similar to those measured in the leaves of Medicago truncatula in which the crystals are known to play a defensive role. Visual inspection of the different engineered lines, however, suggested a phenotypic consequence on plant growth and development with higher calcium oxalate concentrations. The restoration of a near wild-type plant phenotype through an enzymatic reduction of tissue oxalate supported this observation. Overall, this study is a first to provide initial insight into the potential consequences of engineering calcium oxalate crystal formation in non-crystal accumulating plants.

  14. An Assessment of Engineered Calcium Oxalate Crystal Formation on Plant Growth and Development as a Step toward Evaluating Its Use to Enhance Plant Defense

    PubMed Central

    Nakata, Paul A.

    2015-01-01

    The establishment of new approaches to control chewing insects has been sought not only for direct use in reducing crop loss but also in managing resistance to the pesticides already in use. Engineered formation of calcium oxalate crystals is a potential strategy that could be developed to fulfill both these needs. As a step toward this development, this study investigates the effects of transforming a non-calcium oxalate crystal accumulating plant, Arabidopsis thaliana, into a crystal accumulating plant. Calcium oxalate crystal accumulating A. thaliana lines were generated by ectopic expression of a single bacterial gene encoding an oxalic acid biosynthetic enzyme. Biochemical and cellular studies suggested that the engineered A. thaliana lines formed crystals of calcium oxalate in a manner similar to naturally occurring crystal accumulating plants. The amount of calcium oxalate accumulated in leaves also reached levels similar to those measured in the leaves of Medicago truncatula in which the crystals are known to play a defensive role. Visual inspection of the different engineered lines, however, suggested a phenotypic consequence on plant growth and development with higher calcium oxalate concentrations. The restoration of a near wild-type plant phenotype through an enzymatic reduction of tissue oxalate supported this observation. Overall, this study is a first to provide initial insight into the potential consequences of engineering calcium oxalate crystal formation in non-crystal accumulating plants. PMID:26517544

  15. Inhibition of calcium oxalate monohydrate growth by citrate and the effect of the background electrolyte

    NASA Astrophysics Data System (ADS)

    Weaver, Matthew L.; Qiu, S. Roger; Hoyer, John R.; Casey, William H.; Nancollas, George H.; De Yoreo, James J.

    2007-08-01

    Pathological mineralization is a common phenomenon in broad range of plants and animals. In humans, kidney stone formation is a well-known example that afflicts approximately 10% of the population. Of the various calcium salt phases that comprise human kidney stones, the primary component is calcium oxalate monohydrate (COM). Citrate, a naturally occurring molecule in the urinary system and a common therapeutic agent for treating stone disease, is a known inhibitor of COM. Understanding the physical mechanisms of citrate inhibition requires quantification of the effects of both background electrolytes and citrate on COM step kinetics. Here we report the results of an in situ AFM study of these effects, in which we measure the effect of the electrolytes LiCl, NaCl, KCl, RbCl, and CsCl, and the dependence of step speed on citrate concentration for a range of COM supersaturations. We find that varying the background electrolyte results in significant differences in the measured step speeds and in step morphology, with KCl clearly producing the smallest impact and NaCl the largest. The kinetic coefficient for the former is nearly three times larger than for the latter, while the steps change from smooth to highly serrated when KCl is changed to NaCl. The results on the dependence of step speed on citrate concentration show that citrate produces a dead zone whose width increases with citrate concentration as well as a continual reduction in kinetic coefficient with increasing citrate level. We relate these results to a molecular-scale view of inhibition that invokes a combination of kink blocking and step pinning. Furthermore, we demonstrate that the classic step-pinning model of Cabrera and Vermilyea (C-V model) does an excellent job of predicting the effect of citrate on COM step kinetics provided the model is reformulated to more realistically account for impurity adsorption, include an expression for the Gibbs-Thomson effect that is correct for all supersaturations

  16. Sulfate and thiosulfate inhibit oxalate transport via a dPrestin (Slc26a6)-dependent mechanism in an insect model of calcium oxalate nephrolithiasis.

    PubMed

    Landry, Greg M; Hirata, Taku; Anderson, Jacob B; Cabrero, Pablo; Gallo, Christopher J R; Dow, Julian A T; Romero, Michael F

    2016-01-15

    Nephrolithiasis is one of the most common urinary tract disorders, with the majority of kidney stones composed of calcium oxalate (CaOx). Given its prevalence (US occurrence 10%), it is still poorly understood, lacking progress in identifying new therapies because of its complex etiology. Drosophila melanogaster (fruitfly) is a recently developed model of CaOx nephrolithiasis. Effects of sulfate and thiosulfate on crystal formation were investigated using the Drosophila model, as well as electrophysiological effects on both Drosophila (Slc26a5/6; dPrestin) and mouse (mSlc26a6) oxalate transporters utilizing the Xenopus laevis oocyte heterologous expression system. Results indicate that both transport thiosulfate with a much higher affinity than sulfate Additionally, both compounds were effective at decreasing CaOx crystallization when added to the diet. However, these results were not observed when compounds were applied to Malpighian tubules ex vivo. Neither compound affected CaOx crystallization in dPrestin knockdown animals, indicating a role for principal cell-specific dPrestin in luminal oxalate transport. Furthermore, thiosulfate has a higher affinity for dPrestin and mSlc26a6 compared with oxalate These data indicate that thiosulfate's ability to act as a competitive inhibitor of oxalate via dPrestin, can explain the decrease in CaOx crystallization seen in the presence of thiosulfate, but not sulfate. Overall, our findings predict that thiosulfate or oxalate-mimics may be effective as therapeutic competitive inhibitors of CaOx crystallization.

  17. Sulfate and thiosulfate inhibit oxalate transport via a dPrestin (Slc26a6)-dependent mechanism in an insect model of calcium oxalate nephrolithiasis

    PubMed Central

    Landry, Greg M.; Hirata, Taku; Anderson, Jacob B.; Cabrero, Pablo; Gallo, Christopher J. R.; Dow, Julian A. T.

    2015-01-01

    Nephrolithiasis is one of the most common urinary tract disorders, with the majority of kidney stones composed of calcium oxalate (CaOx). Given its prevalence (US occurrence 10%), it is still poorly understood, lacking progress in identifying new therapies because of its complex etiology. Drosophila melanogaster (fruitfly) is a recently developed model of CaOx nephrolithiasis. Effects of sulfate and thiosulfate on crystal formation were investigated using the Drosophila model, as well as electrophysiological effects on both Drosophila (Slc26a5/6; dPrestin) and mouse (mSlc26a6) oxalate transporters utilizing the Xenopus laevis oocyte heterologous expression system. Results indicate that both transport thiosulfate with a much higher affinity than sulfate Additionally, both compounds were effective at decreasing CaOx crystallization when added to the diet. However, these results were not observed when compounds were applied to Malpighian tubules ex vivo. Neither compound affected CaOx crystallization in dPrestin knockdown animals, indicating a role for principal cell-specific dPrestin in luminal oxalate transport. Furthermore, thiosulfate has a higher affinity for dPrestin and mSlc26a6 compared with oxalate These data indicate that thiosulfate's ability to act as a competitive inhibitor of oxalate via dPrestin, can explain the decrease in CaOx crystallization seen in the presence of thiosulfate, but not sulfate. Overall, our findings predict that thiosulfate or oxalate-mimics may be effective as therapeutic competitive inhibitors of CaOx crystallization. PMID:26538444

  18. Plants defective in calcium oxalate crystal formation have more bioavailable calcium

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Bioavailable calcium affects bone formation and calcification. Here we investigate how a single gene mutation altering calcium partitioning in the forage crop Medicago truncatula affects calcium bioavailability. Previously, the cod5 Medicago mutant was identified which contains wild-type amounts o...

  19. Size-dependent cellular uptake mechanism and cytotoxicity toward calcium oxalate on Vero cells

    NASA Astrophysics Data System (ADS)

    Sun, Xin-Yuan; Gan, Qiong-Zhi; Ouyang, Jian-Ming

    2017-02-01

    Urinary crystals with various sizes are present in healthy individuals and patients with kidney stone; however, the cellular uptake mechanism of calcium oxalate of various sizes has not been elucidated. This study aims to compare the internalization of nano-/micron-sized (50 nm, 100 nm, and 1 μm) calcium oxalate monohydrate (COM) and dihydrate (COD) crystals in African green monkey renal epithelial (Vero) cells. The internalization and adhesion of COM and COD crystals to Vero cells were enhanced with decreasing crystal size. Cell death rate was positively related to the amount of adhered and internalized crystals and exhibited higher correlation with internalization than that with adhesion. Vero cells mainly internalized nano-sized COM and COD crystals through clathrin-mediated pathways as well as micron-sized crystals through macropinocytosis. The internalized COM and COD crystals were distributed in the lysosomes and destroyed lysosomal integrity to some extent. The results of this study indicated that the size of crystal affected cellular uptake mechanism, and may provide an enlightenment for finding potential inhibitors of crystal uptake, thereby decreasing cell injury and the occurrence of kidney stones.

  20. Size-dependent cellular uptake mechanism and cytotoxicity toward calcium oxalate on Vero cells

    PubMed Central

    Sun, Xin-Yuan; Gan, Qiong-Zhi; Ouyang, Jian-Ming

    2017-01-01

    Urinary crystals with various sizes are present in healthy individuals and patients with kidney stone; however, the cellular uptake mechanism of calcium oxalate of various sizes has not been elucidated. This study aims to compare the internalization of nano-/micron-sized (50 nm, 100 nm, and 1 μm) calcium oxalate monohydrate (COM) and dihydrate (COD) crystals in African green monkey renal epithelial (Vero) cells. The internalization and adhesion of COM and COD crystals to Vero cells were enhanced with decreasing crystal size. Cell death rate was positively related to the amount of adhered and internalized crystals and exhibited higher correlation with internalization than that with adhesion. Vero cells mainly internalized nano-sized COM and COD crystals through clathrin-mediated pathways as well as micron-sized crystals through macropinocytosis. The internalized COM and COD crystals were distributed in the lysosomes and destroyed lysosomal integrity to some extent. The results of this study indicated that the size of crystal affected cellular uptake mechanism, and may provide an enlightenment for finding potential inhibitors of crystal uptake, thereby decreasing cell injury and the occurrence of kidney stones. PMID:28150811

  1. Phase transformation of calcium oxalate dihydrate-monohydrate: Effects of relative humidity and new spectroscopic data

    NASA Astrophysics Data System (ADS)

    Conti, Claudia; Casati, Marco; Colombo, Chiara; Realini, Marco; Brambilla, Luigi; Zerbi, Giuseppe

    2014-07-01

    New data on vibrational properties of calcium oxalates and their controversial transformation mechanism are presented. We have focused on whewellite (CaC2O4·H2O) and weddellite [CaC2O4·(2 + x) H2O], the most common phases of calcium oxalate; these compounds occur in many organisms, in kidney stones and in particular kinds of films found on the surface of many works of art. Low temperature experiments carried out by Fourier transform infrared spectroscopy have highlighted both the high structural order in the crystalline state of whewellite and the disordered distribution of the zeolitic water molecules in weddellite. The synthesised nanocrystals of weddellite have been kept under different hygrometric conditions in order to study, by X-ray powder diffraction, the role of “external” water molecules on their stability. Moreover, in order to identify the different kinds of water molecules, a re-investigation, supported by quantum chemical calculations, of the observed vibrational spectra (IR and Raman) of whewellite has been conducted.

  2. Calcium Oxalate Stone Agglomeration Inhibition [tm] Reflects Renal Stone-Forming Activity.

    PubMed

    Lindberg, J S; Cole, F E; Romani, W; Husserl, F E; Fuselier, H A; Kok, D J; Erwin, D T

    2000-04-01

    Louisiana and other Gulf South states comprise a "Stone Belt" where calcium oxalate stone formers (CaOx SFs) are found at a high rate of approximately 5%. In these patients, the agglomeration of small stone crystals, which are visible in nearly all morning urine collections, forms stones that can become trapped in the renal parenchyma and the renal pelvis. Without therapy, about half of CaOx SFs repeatedly form kidney stones, which can cause excruciating pain that can be relieved by passage, fragmentation (lithotripsy), or surgical removal. The absence of stones in "normal" patients suggests that there are stone inhibitors in "normal" urines.At the Ochsner Renal Stone Clinic, 24-hour urine samples are collected by the patient and sent to the Ochsner Renal Stone Research Program where calcium oxalate stone agglomeration inhibition [tm] measurements are performed. Urine from healthy subjects and inactive stone formers has demonstrated strongly inhibited stone growth [tm] in contrast to urine from recurrent CaOx SFs. [tm] data from 1500 visits of 700 kidney stone patients have been used to evaluate the risk of recurrence in Ochsner's CaOx SF patients. These data have also been used to demonstrate the interactive roles of certain identified urinary stone-growth inhibitors, citrate and Tamm-Horsfall protein (THP), which can be manipulated with medication to diminish recurrent stone formation. Our goal is to offer patients both financial and pain relief by reducing their stones with optimized medication, using medical management to avoid costly treatments.

  3. Raman spectroscopic analysis of the calcium oxalate producing extremotolerant lichen Circinaria gyrosa

    NASA Astrophysics Data System (ADS)

    Böttger, U.; Meessen, J.; Martinez-Frias, J.; Hübers, H.-W.; Rull, F.; Sánchez, F. J.; de la Torre, R.; de Vera, J.-P.

    2014-01-01

    In the context of astrobiological exposure and simulation experiments in the BIOMEX project, the lichen Circinaria gyrosa was investigated by Raman microspectroscopy. Owing to the symbiotic nature of lichens and their remarkable extremotolerance, C. gyrosa represents a valid model organism in recent and current astrobiological research. Biogenic compounds of C. gyrosa were studied that may serve as biomarkers in Raman assisted remote sensing missions, e.g. ExoMars. The surface as well as different internal layers of C. gyrosa have been characterized and data on the detectability and distribution of β-carotene, chitin and calcium oxalate monohydrate (whewellite) are presented in this study. Raman microspectroscopy was applied on natural samples and thin sections. Although calcium oxalates can also be formed by rare geological processes it may serve as a suitable biomarker for astrobiological investigations. In the model organism C. gyrosa, it forms extracellular crystalline deposits embedded in the intra-medullary space and its function is assumed to balance water uptake and gas exchange during the rare, moist to wet environmental periods that are physiologically favourable. This is a factor that was repeatedly demonstrated to be essential for extremotolerant lichens and other organisms. Depending on the decomposition processes of whewellite under extraterrestrial environmental conditions, it may not only serve as a biomarker of recent life, but also of past and fossilized organisms.

  4. Size-dependent cellular uptake mechanism and cytotoxicity toward calcium oxalate on Vero cells.

    PubMed

    Sun, Xin-Yuan; Gan, Qiong-Zhi; Ouyang, Jian-Ming

    2017-02-02

    Urinary crystals with various sizes are present in healthy individuals and patients with kidney stone; however, the cellular uptake mechanism of calcium oxalate of various sizes has not been elucidated. This study aims to compare the internalization of nano-/micron-sized (50 nm, 100 nm, and 1 μm) calcium oxalate monohydrate (COM) and dihydrate (COD) crystals in African green monkey renal epithelial (Vero) cells. The internalization and adhesion of COM and COD crystals to Vero cells were enhanced with decreasing crystal size. Cell death rate was positively related to the amount of adhered and internalized crystals and exhibited higher correlation with internalization than that with adhesion. Vero cells mainly internalized nano-sized COM and COD crystals through clathrin-mediated pathways as well as micron-sized crystals through macropinocytosis. The internalized COM and COD crystals were distributed in the lysosomes and destroyed lysosomal integrity to some extent. The results of this study indicated that the size of crystal affected cellular uptake mechanism, and may provide an enlightenment for finding potential inhibitors of crystal uptake, thereby decreasing cell injury and the occurrence of kidney stones.

  5. Risk factors associated with calcium oxalate urolithiasis in dogs evaluated at general care veterinary hospitals in the United States.

    PubMed

    Okafor, Chika C; Lefebvre, Sandra L; Pearl, David L; Yang, Mingyin; Wang, Mansen; Blois, Shauna L; Lund, Elizabeth M; Dewey, Cate E

    2014-08-01

    Calcium oxalate urolithiasis results from the formation of aggregates of calcium salts in the urinary tract. Difficulties associated with effectively treating calcium oxalate urolithiasis and the proportional increase in the prevalence of calcium oxalate uroliths relative to other urolith types over the last 2 decades has increased the concern of clinicians about this disease. To determine factors associated with the development of calcium oxalate urolithiasis in dogs evaluated at general care veterinary hospitals in the United States, a retrospective case-control study was performed. A national electronic database of medical records of all dogs evaluated between October 1, 2007 and December 31, 2010 at 787 general care veterinary hospitals in the United States was reviewed. Dogs were selected as cases at the first-time diagnosis of a laboratory-confirmed urolith comprised of at least 70% calcium oxalate (n=452). Two sets of control dogs with no history of urolithiasis diagnosis were randomly selected after the medical records of all remaining dogs were reviewed: urinalysis examination was a requirement in the selection of one set (n=1808) but was not required in the other set (n=1808). Historical information extracted included urolith composition, dog's diet, age, sex, neuter status, breed size category, hospital location, date of diagnosis, and urinalysis results. Multivariable analysis showed that the odds of first-time diagnosis of calcium oxalate urolithiasis were significantly (P<0.05) greater for dogs<7 years, males (OR: 7.77, 95% CI: 4.93-12.26), neutered (OR: 2.58, 1.44-4.63), toy- vs. medium-sized breeds (OR: 3.15, 1.90-5.22), small- vs. medium-sized breeds (OR: 3.05, 1.83-5.08), large- vs. medium-sized breeds (OR: 0.05, 0.01-0.19), and those with a diagnosis of cystitis within the previous year (OR: 6.49, 4.14-10.16). Urinary factors significantly associated with first-time diagnosis of calcium oxalate urolithiasis were acidic vs. basic pH (OR: 1.94, 1

  6. Biosynthesis of L-ascorbic acid and conversion of carbons 1 and 2 of L-ascorbic acid to oxalic acid occurs within individual calcium oxalate crystal idioblasts.

    PubMed

    Kostman, T A; Tarlyn, N M; Loewus, F A; Franceschi, V R

    2001-02-01

    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.

  7. Studies using a porcine model: what insights into human calcium oxalate stone formation mechanisms has this model facilitated?

    PubMed

    Penniston, Kristina L; Patel, Sutchin R; Schwahn, Denise J; Nakada, Stephen Y

    2017-02-01

    Animal models are useful in the study of many human diseases. Our current understanding of the biological, physiological, and biochemical aspects of hyperoxaluria and calcium oxalate urolithiasis has been greatly informed by studies using animals. Recently, limitations in the extrapolation to humans of research results derived from laboratory rodents have been identified. The use in biomedical research of a variety of organisms, including large animals, is increasingly encouraged. The purpose of this article is to review the use of pigs in biomedical and stone research, to provide a rationale for using pigs in metabolic stone research, and to describe our 8-year experience in developing a porcine platform for studying hyperoxaluria and calcium oxalate urolithiasis. In this article, we share and review some of the highlights of our findings. We also report results from a recent feeding swine study that demonstrated oxalate-induced renal nephropathy. Finally, we offer ideas for future directions in urolithiasis research using swine.

  8. Physical characteristics of calcium oxalate crystals as determinants in structural defense against chewing insects in Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In addition to the numerous chemical defenses that plants employ to fend off insect herbivores, simple structural components can also play important roles in effective protection. Our investigations have shown that plant crystals of calcium oxalate can function in insect defense. The isolation of ca...

  9. Medicago truncatula-derived calcium oxalate crystals have a negative impact on chewing insect performance via their physical properties

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Plant structural traits often act as defenses against herbivorous insects, causing them to avoid feeding on a given plant or tissue. Mineral crystals of calcium oxalate in Medicago truncatula Gaertn. (Fabaceae) leaves have previously been shown to be effective deterrents of lepidopteran insect feedi...

  10. Calcium oxalate deposition in renal allografts: morphologic spectrum and clinical implications.

    PubMed

    Truong, Luan D; Yakupoglu, Ulkem; Feig, Daniel; Hicks, John; Cartwight, Joiner; Sheikh-Hamad, David; Suki, Wadi N

    2004-08-01

    Many aspects of calcium oxalate (CaOx) deposition in renal transplant biopsies are not known. Review of all renal transplant biopsies performed in a 7-year period showed that CaOx deposition could be classified into three groups. Group I: Seven biopsies within a month post-transplant displayed rare CaOx foci against a background of acute tubular necrosis or acute cell-mediated rejection. At follow-up, five grafts functioned well and two failed due to chronic allograft nephropathy. CaOx in this context was an incidental finding secondary to a sudden excretion of an end-stage renal disease-induced increased body burden of CaOx. Group II: Two biopsies performed 2 and 10 months post-transplant showed rare CaOx foci against a background of chronic allograft nephropathy, leading to graft loss. CaOx in this context reflected nonspecific parenchymal deposition due to chronic renal failure regardless of causes. Group III: One biopsy with recurrent PH1 characterized by marked CaOx deposition associated with severe tubulointerstitial injury and graft loss 6 months post-transplant. There were two previously reported cases in which CaOx deposition in the renal allografts was due the antihypertensive drug naftidrofuryl oxalate or increased intestinal absorption of CaOx. CaOx deposition in renal allografts can be classified in different categories with distinctive morphologic features and clinical implications.

  11. The mechanism of calcium oxalate crystal-induced haemolysis of human erythrocytes.

    PubMed Central

    Elferink, J. G.

    1987-01-01

    Calcium oxalate (CaOx) crystals cause membrane damage in human erythrocytes, evident from K+ leakage and haemoglobin release. Whereas the hydrogen acceptor polyvinylpyridine-N-oxide is without effect on CaOx crystal-induced haemolysis, polyanions and negative proteins are strongly inhibitory. This indicates that positive charges are of importance for induction of haemolysis. These positive charges are located on the CaOx crystals. Removal of the negatively charged sialic acid from the cell surface does not affect CaOx crystal-induced haemolysis. CaOx crystals are able to release glucose from negatively charged liposomes, but not from positively charged liposomes. The results are compatible with the view that positive charges on the crystals are of predominant importance in CaOx-induced haemolysis, and that their interactions with negative charges or polarizable structures in the lipid part of the membrane leads to membrane disruption. PMID:2443155

  12. Calcium oxalate monohydrate crystals internalized into renal tubular cells are degraded and dissolved by endolysosomes.

    PubMed

    Chaiyarit, Sakdithep; Singhto, Nilubon; Thongboonkerd, Visith

    2016-02-25

    Interaction between calcium oxalate crystals and renal tubular cells has been recognized as one of the key mechanisms for kidney stone formation. While crystal adhesion and internalization have been extensively investigated, subsequent phenomena (i.e. crystal degradation and dissolution) remained poorly understood. To explore these mechanisms, we used fluorescein isothiocyanate (FITC)-labelled calcium oxalate monohydrate (COM) crystals (1000 μg/ml of crystals/culture medium) to confirm crystal internalization into MDCK (Type II) renal tubular cells after exposure to the crystals for 1 h and to trace the internalized crystals. Crystal size, intracellular and extracellular fluorescence levels were measured using a spectrofluorometer for up to 48 h after crystal internalization. Moreover, markers for early endosome (Rab5), late endosome (Rab7) and lysosome (LAMP-2) were examined by laser-scanning confocal microscopy. Fluorescence imaging and flow cytometry confirmed that FITC-labelled COM crystals were internalized into MDCK cells (14.83 ± 0.85%). The data also revealed a reduction of crystal size in a time-dependent manner. In concordance, intracellular and extracellular fluorescence levels were decreased and increased, respectively, indicating crystal degradation/dissolution inside the cells and the degraded products were eliminated extracellularly. Moreover, Rab5 and Rab7 were both up-regulated and were also associated with the up-regulated LAMP-2 to form large endolysosomes in the COM-treated cells at 16-h after crystal internalization. We demonstrate herein, for the first time, that COM crystals could be degraded/dissolved by endolysosomes inside renal tubular cells. These findings will be helpful to better understand the crystal fate and protective mechanism against kidney stone formation.

  13. Prophylactic effects of quercetin and hyperoside in a calcium oxalate stone forming rat model.

    PubMed

    Zhu, Wei; Xu, Yun-fei; Feng, Yuan; Peng, Bo; Che, Jian-ping; Liu, Min; Zheng, Jun-hua

    2014-12-01

    Quercetin and hyperoside (QH) are the two main constituents of the total flavone glycosides of Flos Abelmoschus manihot, which has been prescribed for treating chronic kidney disease for decades. This study aimed to investigate the effect of QH on calcium oxalate (CaOx) formation in ethylene glycol (EG)-fed rats. Rats were divided into three groups: an untreated stone-forming group, a QH-treated stone-forming group (20 mg/kg/day) and a potassium citrate-treated stone-forming group (potassium citrate was a worldwide-recognized calculi-prophylactic medicine). Ethylene glycol (0.5 %) was administered to the rats during the last week, and vitamin D3 was force-fed to induce hyperoxaluria and kidney calcium oxalate crystal deposition. 24 h urine samples were collected before and after inducing crystal deposits. Rats were killed and both kidneys were harvested after 3 weeks. Bisected kidneys were examined under a polarized light microscope for semi-quantification of the crystal-formation. The renal tissue superoxide dismutase and catalase levels were measured by Western blot. QH and potassium citrate have the ability to alkalinize urine. The number of crystal deposits decreased significantly in the QH-treated stone-forming group as compared to the other groups. Superoxide dismutase and catalase levels also increased significantly in the QH-treated stone-forming group, as compared with the untreated stone-forming group. QH administration has an inhibitory effect on the deposition of CaOx crystal in EG-fed rats and may be effective for preventing stone-forming disease.

  14. Toward a new insight of calcium oxalate stones in Drosophila by micro-computerized tomography.

    PubMed

    Chen, Wen-Chi; Chen, Huey-Yi; Liao, Po-Chi; Wang, Shih-Jing; Tsai, Ming-Yen; Chen, Yung-Hsiang; Lin, Wei-Yong

    2017-03-04

    We previously developed an animal model of calcium oxalate (CaOx) deposition on the Malphigian tubules of Drosophila melanogaster as a model of urolithiasis. Here, we introduce a new tool for the study of anatomical structure for Drosophila. As a consequence of technical development, the invention of micro-computerized tomography (CT) has been introduced to the small animal, such as rat and mice. We used Drosophila as a model organism and fed the flies 0.5% lithogenic agent ethylene glycol for 3 weeks. Samples were simply prepared for further scanned by micro-CT to scan samples at 800 nm resolution. CT scanning was performed at 40 kVp of voltage, 250 μA of current, and 1750 ms of exposure time and without filter. Reconstruction of sections was carried out with the GPU-based scanner software. Specific region of interests was further analyzed by DataViewer software. Area with high radiologic density level was defined as CaOx deposition for further 3D analysis. Image of whole lithogenic Drosophila was compared with control. High radiologic density level was detected in the region of Malphigian tubules which can be identified as CaOx stones. There was no stone image in the control group. The image was the same as human non-contrast CT for the diagnosis of stone disease. Micro-CT clearly demonstrated the calcium oxalate calcifications in the Malphigian tubules of fruit fly. The image system provides that a new vision on study animal will facilitate further study of stone disease. With the development of new technology on micro-CT, more delicate and advanced image will be presented in the future.

  15. Wu-Ling-San formula prophylaxis against recurrent calcium oxalate nephrolithiasis - a prospective randomized controlled trial.

    PubMed

    Lin, Eugene; Ho, Lin; Lin, Mao-Sheng; Huang, Min-Ho; Chen, Wen-Chi

    2013-01-01

    Wu-Ling-San (WLS) formula has been proved to prevent calcium oxalate nephrolithiasis both in vitro and in vivo. This is the first prospective, randomized and placebo-controlled clinical trial of WLS in calcium oxalate nephrolithiasis prevention. All patients who enrolled were asked to drink enough fluid to urinate at least 2 L daily during the study period. A 24-hour urine collection was performed to establish the baseline levels of multiple urinary parameters before taking the medicine. The patients were randomized and divided into two groups. The medication group took 2 gm WLS formula three times daily for 1 month. The control group took 2 gm placebo three times daily for 1 month. A 24-hour urine collection was performed to evaluate multiple urinary and serum parameters from all patients during the study period. A total of 39 patients were enrolled and 28 patients completed the study. Fourteen patients were allocated to WLS group and 14 patients to placebo group. After treatment, the mean urine output level increased to 2796.4 ± 525.7 ml/day (percentage of change, 13.9 %) in the WLS formula group. With placebo therapy, the mean decreased slightly to 2521.4 ± 762.7ml/day (percentage of change, -5.7 %). The percentage of change was significantly different between the two groups (independent t-test, P=0.02). No patient complained of side effects, such as fatigue, dizziness, musculoskeletal symptoms, or gastrointestinal disturbance. WLS formula is a promising adjunct to surgical and medical management of kidney stones. Active therapy with WLS formula has a positive effect on diuresis without leading to electrolyte imbalance.

  16. High Sodium-Induced Oxidative Stress and Poor Anticrystallization Defense Aggravate Calcium Oxalate Crystal Formation in Rat Hyperoxaluric Kidneys.

    PubMed

    Huang, Ho-Shiang; Ma, Ming-Chieh

    2015-01-01

    Enhanced sodium excretion is associated with intrarenal oxidative stress. The present study evaluated whether oxidative stress caused by high sodium (HS) may be involved in calcium oxalate crystal formation. Male rats were fed a sodium-depleted diet. Normal-sodium and HS diets were achieved by providing drinking water containing 0.3% and 3% NaCl, respectively. Rats were fed a sodium-depleted diet with 5% hydroxyl-L-proline (HP) for 7 and 42 days to induce hyperoxaluria and/or calcium oxalate deposition. Compared to normal sodium, HS slightly increased calcium excretion despite diuresis; however, the result did not reach statistical significance. HS did not affect the hyperoxaluria, hypocalciuria or supersaturation caused by HP; however, it increased calcium oxalate crystal deposition soon after 7 days of co-treatment. Massive calcium oxalate formation and calcium crystal excretion in HS+HP rats were seen after 42 days of treatment. HP-mediated hypocitraturia was further exacerbated by HS. Moreover, HS aggravated HP-induced renal injury and tubular damage via increased apoptosis and oxidative stress. Increased urinary malondialdehyde excretion, in situ superoxide production, NAD(P)H oxidase and xanthine oxidase expression and activity, and decreased antioxidant enzyme expression or activity in the HS+HP kidney indicated exaggerated oxidative stress. Interestingly, this redox imbalance was associated with reduced renal osteopontin and Tamm-Horsfall protein expression (via increased excretion) and sodium-dependent dicarboxylate cotransporter NaDC-1 upregulation. Collectively, our results demonstrate that a HS diet induces massive crystal formation in the hyperoxaluric kidney; this is not due to increased urinary calcium excretion but is related to oxidative injury and loss of anticrystallization defense.

  17. Evaluation of Pt Alloys as Electrocatalysts for Oxalic Acid Oxidation: A Combined Experimental and Computational Study

    DOE PAGES

    Perry, Albert; Babanova, Sofia; Matanovic, Ivana; ...

    2016-07-14

    Here in this study we combined experimental approaches and density functional theory to evaluate novel platinum-based materials as electrocatalysts for oxalic acid oxidation. Several Pt alloys, PtSn (1:1), PtSn (19:1), PtRu (1:4), PtRuSn (5:4:1), and PtRhSn (3:1:4), were synthetized using sacrificial support method and tested for oxidation of oxalic acid at pH 4. It was shown that PtSn (1:1) and PtRu (1:4) have higher mass activity relative to Pt. These two materials along with Pt and one of the least active alloys, PtSn (19:1), were further analyzed for the oxidation of oxalic acid at different pHs. The results show thatmore » all samples tested followed an identical trend of decreased onset potential with increased pH and increased catalytic activity with decreased pH. Density functional theory was further utilized to gain a fundamental knowledge about the mechanism of oxalic acid oxidation on Pt, PtSn (1:1), and PtRu (1:4). In conclusion, the results of the calculations along with the experimentally observed dependence of generated currents on the oxalic acid concentration indicate that the mechanism of oxalic acid oxidation on Pt proceeds without the participation of surface oxidizing species, while on Pt alloys it involves their participation.« less

  18. Evaluation of Pt Alloys as Electrocatalysts for Oxalic Acid Oxidation: A Combined Experimental and Computational Study

    SciTech Connect

    Perry, Albert; Babanova, Sofia; Matanovic, Ivana; Neumman, Anica; Serov, Alexey; Artyushkova, Kateryna; Atanassov, Plamen

    2016-07-14

    Here in this study we combined experimental approaches and density functional theory to evaluate novel platinum-based materials as electrocatalysts for oxalic acid oxidation. Several Pt alloys, PtSn (1:1), PtSn (19:1), PtRu (1:4), PtRuSn (5:4:1), and PtRhSn (3:1:4), were synthetized using sacrificial support method and tested for oxidation of oxalic acid at pH 4. It was shown that PtSn (1:1) and PtRu (1:4) have higher mass activity relative to Pt. These two materials along with Pt and one of the least active alloys, PtSn (19:1), were further analyzed for the oxidation of oxalic acid at different pHs. The results show that all samples tested followed an identical trend of decreased onset potential with increased pH and increased catalytic activity with decreased pH. Density functional theory was further utilized to gain a fundamental knowledge about the mechanism of oxalic acid oxidation on Pt, PtSn (1:1), and PtRu (1:4). In conclusion, the results of the calculations along with the experimentally observed dependence of generated currents on the oxalic acid concentration indicate that the mechanism of oxalic acid oxidation on Pt proceeds without the participation of surface oxidizing species, while on Pt alloys it involves their participation.

  19. Using MRI to detect and differentiate calcium oxalate and calcium hydroxyapatite crystals in air-bubble-free phantom.

    PubMed

    Mustafi, Devkumar; Fan, Xiaobing; Peng, Bo; Foxley, Sean; Palgen, Jeremy; Newstead, Gillian M

    2015-12-01

    Calcium oxalate (CaOX) crystals and calcium hydroxyapatite (CaHA) crystals were commonly associated with breast benign and malignant lesions, respectively. In this research, CaOX (n = 6) and CaHA (n = 6) crystals in air-bubble-free agarose phantom were studied and characterized by using MRI at 9.4 T scanner. Calcium micro-crystals, with sizes that ranged from 200 to 500 µm, were made with either 99% pure CaOX or CaHA powder and embedded in agar to mimic the dimensions and calcium content of breast microcalcifications in vivo. MRI data were acquired with high spatial resolution T2-weighted (T2W) images and gradient echo images with five different echo times (TEs). The crystal areas were determined by setting the threshold relative to agarose signal. The ratio of crystal areas was calculated by the measurements from gradient echo images divided by T2W images. Then the ratios as a function of TE were fitted with the radical function. The results showed that the blooming artifacts due to magnetic susceptibility between agar and CaHA crystals were more than twice as large as the susceptibility in CaOX crystals (p < 0.05). In addition, larger bright rings were observed on gradient echo images around CaHA crystals compared to CaOX crystals. Our results suggest that MRI may provide useful information regarding breast microcalcifications by evaluating the apparent area of crystal ratios obtained between gradient echo and T2W images.

  20. Nutrient intake and urine composition in calcium oxalate stone-forming dogs: comparison with healthy dogs and impact of dietary modification.

    PubMed

    Stevenson, Abigail E; Blackburn, Judith M; Markwell, Peter J; Robertson, William G

    2004-01-01

    Nutrient intake and urine composition were analyzed in calcium oxalate (CaOx)stone-forming and healthy control dogs to identify factors that contribute to CaOx urolithiasis. Stone-forming dogs had significantly lower intake of sodium, calcium, potassium, and phosphorus and significantly higher urinary calcium and oxalate concentrations, calcium excretion, and CaOx relative supersaturation (RSS). Feeding a diet used in the treatment of canine lower urinary tract disease for 1 month was associated with increased intake of moisture, sodium, and fat; reduced intake of potassium and calcium; and decreased urinary calcium and oxalate concentrations, calcium excretion, and CaOx RSS. No clinical signs of disease recurrence were observed in the stone-forming dogs when the diet was fed for an additional 11 months. The results suggest that hypercalciuria and hyperoxaluria contribute to the formation of CaOx uroliths in dogs and show that dietary modifications can alter this process.

  1. Development of Endoplasmic Reticulum Stress during Experimental Oxalate Nephrolithiasis.

    PubMed

    Motin, Yu G; Lepilov, A V; Bgatova, N P; Zharikov, A Yu; Motina, N V; Lapii, G A; Lushnikova, E L; Nepomnyashchikh, L M

    2016-01-01

    Morphological and ultrastructural study of the kidney was performed in rats with oxalate nephrolithiasis. Specific features of endoplasmic reticulum stress were evaluated during nephrolithiasis and treatment with α-tocopherol. We observed the signs of endoplasmic reticulum stress with activation of proapoptotic pathways and injury to the cell lining in nephron tubules and collecting ducts. Ultrastructural changes were found in the organelles, nuclei, and cell membranes of epitheliocytes. A relationship was revealed between endoplasmic reticulum stress and oxidative damage, which developed at the early state of lithogenesis.

  2. Papillary calcifications: a new prognostic factor in idiopathic calcium oxalate urolithiasis.

    PubMed

    Strohmaier, Walter Ludwig; Hörmann, Markus; Schubert, Gernot

    2013-11-01

    Metabolic evaluation is not suitable to forecast the course of the disease in idiopathic calcium oxalate stone formation (iCaOxU). An important pathway in CaOx stone formation is the overgrowth on interstitial apatite papillary plaques. Therefore, we studied whether the extent of such plaques may be used as a prognostic factor in CaOxU. Prospectively, we studied n = 100 patients with iCaOxU. For stone analysis, X-ray diffraction/polarizing microscopy was used. During flexible ureteroscopy and flexible percutaneous nephrolithotomy, all the renal papillae were inspected, counted and the severity of calcifications assessed. A calcification index (CI) was calculated: sum of the No. of papillae × calcification grade (1-3) × No. of calcified/total No. of papillae. Furthermore, the following parameters were examined in all patients: age, sex, BMI, arterial blood pressure, stone episodes, DM; blood: creatinine, glucose, uric acid, calcium, sodium and potassium; urine: pH, volume, calcium, uric acid, citrate, ammonia and urea. Using the statistic programme Prism 5 (GraphPad), summary statistics and non-parametric correlations (Spearman) and their significance were calculated. The CI correlated significantly (r = 0.37; p = 0.012) with the No. of stone episodes. Apart from citrate (r = 0.51; p = 0.002), none of the conventional metabolic parameters correlated significantly with the No. of stone episodes. Paradoxically, the citrate excretion-although citrate being an inhibitor of CaOx stone formation-positively correlated to the recurrence rate. The endoscopic assessment of papillary plaques/calcifications and the calculation of the CI are a more suitable prognostic factor in CaOx than conventional metabolic evaluation.

  3. Absorption kinetics of oxalate from oxalate-rich food in man.

    PubMed

    Prenen, J A; Boer, P; Dorhout Mees, E J

    1984-11-01

    The absorption of oxalate was investigated in a healthy subject after ingestion of oxalate-rich meals (spinach and rhubarb) with and without addition of 14C-labeled oxalic acid and calcium oxalate, and after oxalate-free meals with addition of nonlabeled sodium oxalate and calcium oxalate. Under these conditions, calcium oxalate was absorbed to the same extent as soluble oxalate; only a small percentage (2.4 +/- 0.7) of the total oxalate load was absorbed. Significant oxalate absorption occurred within 1 to 8 h after ingestion. The results suggest that under normal conditions the proximal part of the small bowel is a major absorption site.

  4. Immunological detection of nitrosative stress-mediated modified Tamm-Horsfall glycoprotein (THP) in calcium oxalate stone formers.

    PubMed

    Pragasam, V; Kalaiselvi, P; Sumitra, K; Srinivasan, S; Anandkumar, P; Varalakshmi, P

    2006-01-01

    The generation of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in hyperoxaluric condition has been proved experimentally. This may result in the formation of the cytotoxic metabolite peroxynitrite, which is capable of causing lipid peroxidation and protein modification. The presence of nitrotyrosine in proteins has been associated with several pathological conditions. The present study investigated the presence of nitrotyrosine in the stone formers Tamm-Horsfall glycoprotein (THP). In vitro nitration of control THP was carried out using peroxynitrite. New Zealand white rabbits were immunized with peroxynitrated THP at 15-day intervals. Antisera collected following the third immunization were assayed for antibody titres using solid-phase ELISA. Antibodies were purified by affinity chromatography. The carbonyl content of control, stone formers and nitrated THP were determined. Western blotting was carried with control, stone formers and nitrated THPs. Immunodiffusion studies demonstrated cross-reaction with nitrated bovine serum albumin. Significant amounts (p < 0.001) of carbonyl content were present in both stone formers and nitrated THPs. Western blot analysis confirmed the presence of nitrated amino acid 3-nitrotyrosine in stone formers, which could bring about structural and functional modifications of THP in hyperoxaluric patients. A cross-reaction with nitrated bovine serum albumin confirms that the raised antibody has certain paratopes similar to the epitope of nitrated protein molecules. Detection of 3-nitrotyrosine in stone formers THP indicates that it is one of the key factors influencing the conversion of THP to a structurally and immunologically altered form during calcium oxalate stone formation.

  5. Specificity in calcium oxalate adherence to papillary epithelial cells in culture

    SciTech Connect

    Riese, R.J.; Riese, J.W.; Kleinman, J.G.; Wiessner, J.H.; Mandel, G.S.; Mandel, N.S. )

    1988-11-01

    Attachment of microcystallites to cellular membranes may be an important component of the pathophysiology of many diseases including urolithiasis. This study attempts to characterize the interaction of calcium oxalate (CaOx) crystals and apatite (AP) crystals with renal papillary collecting tubule (RPCT) cells in primary culture. Primary cultures of RPCT cells showed the characteristic monolayer growth with sporadically interspersed clumped cells. Cultures were incubated with ({sup 14}C)CaOx crystals, and the crystals that bound were quantified by microscopy and adherent radioactivity. Per unit of cross-sectional area, 32 times more CaOx crystals were bound to the clumps than to the monolayer. CaOx adherence demonstrated concentration-dependent saturation with a {beta} value (fraction of cell culture area binding CaOx crystals) of 0.179 and a 1/{alpha}{sub ox} value of 287 {mu}g/cm{sup 2}. On incubation with AP crystals, CaOx binding demonstrated concentration-dependent inhibition with a 1/{alpha}{sub AP} value of 93 {mu}g/cm{sup 2}. Microcystallite adherence to RPCT cells demonstrates selectivity for cellular clumps, saturation, and inhibition. These features suggest specific binding.

  6. Diversity and distribution of idioblasts producing calcium oxalate crystals in Dieffenbachia seguine (Araceae).

    PubMed

    Coté, Gary G

    2009-07-01

    Although cells that synthesize crystals are known throughout the plant kingdom, their functional significance is still unknown. Mechanical support, mineral balance, waste sequestration, and protection against herbivores have all been proposed as crystal functions. To seek clues to their role(s), I systematically examined all organs except fruit of Dieffenbachia seguine (Araceae) for crystals. Crystals were found in nearly every organ. Raphides (long, slim, pointed crystals) were most common, but druses (crystal aggregates) and prisms were also found. Raphides varied in size by a factor of 10 and also in organization from tightly bundled to loosely organized. Biforines, a type of cell capable of expelling raphides, or biforine-like cells, were found in nearly all organs, but especially in leaves, spathes, and anthers. Different organs had different crystal complements, and characteristic crystals were found at specific locations, such as among pollen, along the undersides of leaf veins, and at root branch points. All crystals appeared to be composed of calcium oxalate, based on acid solubility. Possible roles of the crystals are discussed in light of these findings.

  7. Calcium oxalate crystals induce renal inflammation by NLRP3-mediated IL-1β secretion

    PubMed Central

    Mulay, Shrikant R.; Kulkarni, Onkar P.; Rupanagudi, Khader V.; Migliorini, Adriana; Darisipudi, Murthy N.; Vilaysane, Akosua; Muruve, Daniel; Shi, Yan; Munro, Fay; Liapis, Helen; Anders, Hans-Joachim

    2012-01-01

    Nephrocalcinosis, acute calcium oxalate (CaOx) nephropathy, and renal stone disease can lead to inflammation and subsequent renal failure, but the underlying pathological mechanisms remain elusive. Other crystallopathies, such as gout, atherosclerosis, and asbestosis, trigger inflammation and tissue remodeling by inducing IL-1β secretion, leading us to hypothesize that CaOx crystals may induce inflammation in a similar manner. In mice, intrarenal CaOx deposition induced tubular damage, cytokine expression, neutrophil recruitment, and renal failure. We found that CaOx crystals activated murine renal DCs to secrete IL-1β through a pathway that included NLRP3, ASC, and caspase-1. Despite a similar amount of crystal deposits, intrarenal inflammation, tubular damage, and renal dysfunction were abrogated in mice deficient in MyD88; NLRP3, ASC, and caspase-1; IL-1R; or IL-18. Nephropathy was attenuated by DC depletion, ATP depletion, or therapeutic IL-1 antagonism. These data demonstrated that CaOx crystals trigger IL-1β–dependent innate immunity via the NLRP3/ASC/caspase-1 axis in intrarenal mononuclear phagocytes and directly damage tubular cells, leading to the release of the NLRP3 agonist ATP. Furthermore, these results suggest that IL-1β blockade may prevent renal damage in nephrocalcinosis. PMID:23221343

  8. Inhibition of calcium oxalate crystallisation in vitro by an extract of Bergenia ciliata

    PubMed Central

    Saha, Sarmistha; Verma, Ramtej J.

    2013-01-01

    Objective To evaluate the effectiveness of an extract obtained from the rhizomes of Bergenia ciliata (Saxifragaceae) on the inhibition of calcium oxalate (CaOx) crystallisation in vitro. Materials and methods A hydro-alcoholic extract (30:70, v/v) of rhizomes of B. ciliata was prepared at different concentrations (1–10 mg/mL). The crystallisation of CaOx monohydrate (COM) was induced in a synthetic urine system. The nucleation and aggregation of COM crystals were measured using spectrophotometric methods. The rates of nucleation and aggregation were evaluated by comparing the slope of the turbidity of a control system with that of one exposed to the extract. The results were compared with a parallel study conducted with a marketed poly-herbal combination, Cystone, under identical concentrations. Crystals generated in the urine were also analysed by light microscopy. Statistical differences and percentage inhibitions were calculated and assessed. Results The extract of B. ciliata was significantly more effective in inhibiting the nucleation and aggregation of COM crystals in a dose-dependent manner than was Cystone. Moreover, the extract induced more CaOx dihydrate crystals, with a significant reduction in the number and size of COM crystals. Conclusion An extract of the traditional herb B. ciliata has an excellent inhibitory activity on crystalluria and therefore might be beneficial in dissolving urinary stones. However, further study in animal models of urolithiasis is needed to evaluate its potential anti-urolithiatic activity. PMID:26558080

  9. A comparison between effects of pyruvate and herb medicines in preventing experimental oxalate urolithiasis in rats.

    PubMed

    Ogawa, Y; Morozumi, M; Tanaka, T; Yamaguchi, K

    1986-08-01

    Sodium pyruvate, choreito (a herbal preparation), and urajirogashi (a herb) were added to a calcium-oxalate lithogenic diet (a glycolic-acid diet) to determine their effects in preventing lithogenicity. Male Wistar-strain rats which had been fed the glycolic-acid diet developed marked urinary calculi within 4 weeks. Rats in the groups fed a pyruvate diet had, however, almost no stones in the urinary system. The choreito and urajirogashi were slightly less effective than the pyruvate. Urinary oxalate excretion was high in all the groups during the experiment, especially in the pyruvate and the glycolic-acid groups, but, it was relatively lowered in the herb groups, especially towards the end of the experiment (p less than 0.05). Urinary citrate excretion was high in the pyruvate group, but it was significantly low in the other groups. In the choreito group, remarkable increases in urinary volume and magnesium excretion were observed; however, they were statistically non-significant and urinary calcium excretion was higher than in the glycolic-acid group during the experiment. Therefore, it can be concluded that choreito and urajirogashi may have some beneficial effect though any such effect is inferior to that of pyruvate, in preventing calculi formation, partly by decreasing the urinary oxalate excretion; increased urine volume and magnesium excretion may also have some other, additional effects in the choreito group.

  10. Extraction and estimation of the quantity of calcium oxalate crystals in the foliage of conifer and hardwood trees.

    PubMed

    Minocha, Rakesh; Chamberlain, Bradley; Long, Stephanie; Turlapati, Swathi A; Quigley, Gloria

    2015-05-01

    The main goal of this study was to develop a method for the extraction and indirect estimation of the quantity of calcium oxalate (CaOx) in the foliage of trees. Foliar tissue was collected from a single tree of each species (five conifers and five hardwoods) for comparison of extractions in different solvents using 10 replicates per species from the same pool of tissue. For each species, calcium (Ca) and oxalate were extracted sequentially in double deionized water and 2N acetic acid, and finally, five replicate samples were extracted in 5% (0.83N) perchloric acid (PCA) and the other five in 2N hydrochloric acid (HCl); three cycles of freezing and thawing were used for each solvent. Total ions were extracted by microwave digestion. Calcium was quantified with an inductively coupled plasma emission spectrophotometer method and oxalate was eluted and quantified using a high performance liquid chromatography method. This experiment was repeated again with two conifer and two hardwood species using four trees per species, and two analytical replicates for each tree. We report here that, regardless of age of individual trees within a species, time of collection or species type, the third extraction in PCA or HCl resulted in near equimolar quantities of Ca and oxalate (r(2) ≥ 0.99). This method provides an easy estimate of the quantity of CaOx crystals using a small sample of foliar tissue. An additional benefit of PCA is that it precipitates the nucleic acids and proteins, allowing the quantification of several free/soluble metabolites such as amino acids, polyamines, organic acids and inorganic elements all from a single sample extract.

  11. Critical role of oxalate restriction in association with calcium restriction to decrease the probability of being a stone former: insufficient effect in idiopathic hypercalciuria.

    PubMed

    Bataille, P; Pruna, A; Gregoire, I; Charransol, G; de Fremont, J F; Coevoet, B; Galy, C; Fournier, A

    1983-01-01

    The probability of being a stone former (PSF) was calculated according to the method of Robertson in three groups of idiopathic calcium stone formers (normocalciuria (NCa), dietary hypercalciuria (DH) and idiopathic hypercalciuria (IH] during four conditions: on a free diet; on a calcium and oxalate restricted diet for four days and after an oxalate load (200 g of spinach) while on a calcium unrestricted or calcium restricted diet. Combined calciuria (Ca) and oxaluria (Ox) restriction significantly decreased PSF only in NCa and DH whereas the decrease was not significant in IH because of a concomitant significant increase in oxalate excretion. Increase of PSF with the oxalate load was significantly greater on calcium restricted than on calcium unrestricted diets in all groups of patients (4-6-12 times greater in NCa, DH and IH respectively). This shows the critical role of oxalate restriction when calcium is restricted in order to decrease the PSF. Combined restriction is not sufficient in idiopathic hypercalciuric patients to decrease their probability of stone formation.

  12. Isolation of a Crystal Matrix Protein Associated with Calcium Oxalate Precipitation in Vacuoles of Specialized Cells1

    PubMed Central

    Li, Xingxiang; Zhang, Dianzhong; Lynch-Holm, Valerie J.; Okita, Thomas W.; Franceschi, Vincent R.

    2003-01-01

    The formation of calcium (Ca) oxalate crystals is considered to be a high-capacity mechanism for regulating Ca in many plants. Ca oxalate precipitation is not a stochastic process, suggesting the involvement of specific biochemical and cellular mechanisms. Microautoradiography of water lettuce (Pistia stratiotes) tissue exposed to 3H-glutamate showed incorporation into developing crystals, indicating potential acidic proteins associated with the crystals. Dissolution of crystals leaves behind a crystal-shaped matrix “ghost” that is capable of precipitation of Ca oxalate in the original crystal morphology. To assess whether this matrix has a protein component, purified crystals were isolated and analyzed for internal protein. Polyacrylamide gel electrophoresis revealed the presence of one major polypeptide of about 55 kD and two minor species of 60 and 63 kD. Amino acid analysis indicates the matrix protein is relatively high in acidic amino acids, a feature consistent with its solubility in formic acid but not at neutral pH. 45Ca-binding assays demonstrated the matrix protein has a strong affinity for Ca. Immunocytochemical localization using antibody raised to the isolated protein showed that the matrix protein is specific to crystal-forming cells. Within the vacuole, the surface and internal structures of two morphologically distinct Ca oxalate crystals, raphide and druse, were labeled by the antimatrix protein serum, as were the surfaces of isolated crystals. These results demonstrate that a specific Ca-binding protein exists as an integral component of Ca oxalate crystals, which holds important implications with respect to regulation of crystal formation. PMID:14555781

  13. Characterization of calcium oxalate crystal-induced changes in the secretome of U937 human monocytes.

    PubMed

    Sintiprungrat, Kitisak; Singhto, Nilubon; Thongboonkerd, Visith

    2016-03-01

    In kidney stone disease, migratory monocytes have been found to mediate progressive renal inflammation through the secretion of numerous inflammatory mediators. However, whether calcium oxalate monohydrate (COM), which is the major crystalline compound of kidney stones, has any effects on proteins secreted from monocytes remained largely unknown. The present study aimed to characterize changes in the secretome of U937 human monocytes induced by COM crystals. The viability of cells in serum/protein-free medium was serially evaluated and the data revealed that an exposure time of 16 h was optimal for this study, whereas prolonged incubation for 24 h resulted in declined cell viability. Using this optimal time-point, the secreted proteins recovered from serum/protein-free culture supernatants of controlled and COM-treated cells were resolved in 2-DE and stained with Deep Purple fluorescent dye. Quantitative intensity analysis revealed statistically significant changes in levels of 18 secreted proteins (14 increased and 4 decreased) from COM-treated cells. These significantly altered secreted proteins were then identified by Q-TOF MS and/or MS/MS analyses. Among these, the increased levels of secreted heat shock protein 90 (HSP90), HSP70 and β-actin were confirmed by Western blot analysis. The increased level of extracellular HSP90 was confirmed on the COM-treated cell surface by the immunofluorescence study, whereas the increased secretion of IFN-α was validated by ELISA. Global protein network analysis, literature search and bioinformatics revealed that these significantly altered secreted proteins were involved mainly in immune response and cell survival. Therefore, changes in the secretome of monocytes induced by COM crystals may be related, at least in part, to progressive renal inflammation found in kidney stone disease.

  14. M1/M2-macrophage phenotypes regulate renal calcium oxalate crystal development

    PubMed Central

    Taguchi, Kazumi; Okada, Atsushi; Hamamoto, Shuzo; Unno, Rei; Moritoki, Yoshinobu; Ando, Ryosuke; Mizuno, Kentaro; Tozawa, Keiichi; Kohri, Kenjiro; Yasui, Takahiro

    2016-01-01

    In our previous report, M2-macrophage (Mφs) deficient mice showed increased renal calcium oxalate (CaOx) crystal formation; however, the role of Mφs-related-cytokines and chemokines that affect kidney stone formation remains unknown. Here, we investigated the role of M1/M2s in crystal development by using in vitro and in vivo approaches. The crystal phagocytic rate of bone marrow-derived M2Mφs was higher than that of bone marrow-derived Mφs and M1Mφs and increased on co-culture with renal tubular cells (RTCs). However, the amount of crystal attachment on RTCs reduced on co-culture with M2Mφs. In six hyperoxaluric C57BL/6J mice, M1Mφ transfusion and induction by LPS and IFN-γ facilitated renal crystal formation, whereas M2Mφ transfusion and induction by IL-4 and IL-13 suppressed renal crystal formation compared with the control. These M2Mφ treatments reduced the expression of crystal-related genes, such as osteopontin and CD44, whereas M1Mφ treatment increased the expression of pro-inflammatory and adhesion-related genes such as IL-6, inducible NOS, TNF-α, C3, and VCAM-1. The expression of M2Mφ-related genes was lower whereas that of M1Mφ-related genes was higher in papillary tissue of CaOx stone formers. Overall, our results suggest that renal crystal development is facilitated by M1Mφs, but suppressed by M2Mφs. PMID:27731368

  15. Comparison of body condition score and urinalysis variables between dogs with and without calcium oxalate uroliths

    PubMed Central

    Kennedy, Stephanie M.; Lulich, Jody P.; Ritt, Michelle G.; Furrow, Eva

    2017-01-01

    OBJECTIVE To compare body condition score (BCS) and urinalysis variables between dogs with and without calcium oxalate (CaOx) uroliths. DESIGN Case-control study. ANIMALS 46 Miniature Schnauzers, 16 Bichons Frises, and 6 Shih Tzus. PROCEDURES Medical records were reviewed for Miniature Schnauzers, Bichons Frises, and Shih Tzus that were examined between January 2001 and November 2014 for another urolithiasis study or for a urolith removal procedure. Dogs with CaOx uroliths were classified as cases. Dogs without a history of urinary tract disease and with no evidence of radiopaque uroliths on abdominal radiographs were classified as controls. Each case was matched with 1 control on the basis of age (± 2 years), sex, and breed. Body condition score and urinalysis results were compared between cases and controls, and the relationship between BCS and urine pH was analyzed. RESULTS Median BCS was significantly greater for cases than controls, although the proportion of overweight dogs did not differ significantly between the 2 groups. Urine pH was negatively associated with age, but was not associated with BCS or the presence of CaOx uroliths. Cases infrequently had acidic urine or CaOx crystalluria but frequently had hematuria and proteinuria. CONCLUSIONS AND CLINICAL RELEVANCE Results indicated that dogs with CaOx uroliths had a greater median BCS than control dogs, but the clinical importance of that finding was unclear. Acidic urine and CaOx crystalluria were uncommon and not adequate predictors of CaOx urolith status. Hematuria and proteinuria were commonly observed in dogs with CaOx urolithiasis, but they are not pathognomonic for that condition. PMID:27875079

  16. Calcium oxalate nephrolithiasis and tubular necrosis in recent metamorphs of Rana sylvatica (Lithobates sylvaticus) fed spinach during the premetamorphic (tadpole) stage.

    PubMed

    Forzán, M J; Ferguson, L V; Smith, T G

    2015-03-01

    Amphibians in the family Ranidae (true frogs) seem highly susceptible to oxalosis, particularly when fed a diet high in oxalic acid during the premetamorphic (tadpole) stage. The authors describe the mortality of 150 captive-raised wood frogs (Rana sylvatica or Lithobates sylvaticus) from oxalate nephrolithiasis and renal tubular necrosis caused by consumption of boiled spinach during tadpole development. Renal lesions were due to intraluminal transparent crystals which were birefringent under polarized light and were identified morphologically and histochemically as composed of calcium oxalate. Evidence of early fibrosis or squamous metaplasia, and a presentation at least 2 weeks after spinach consumption had ended, suggested a subacute course. Tadpole-feeding protocols should avoid plants with high oxalate content (eg, spinach and rhubarb leaves), and any episode of high mortality in captive amphibians along with nephrolithiasis should prompt an evaluation of the feed sources for material with high oxalate content.

  17. Calcium release from experimental dental materials.

    PubMed

    Okulus, Zuzanna; Buchwald, Tomasz; Voelkel, Adam

    2016-11-01

    The calcium release from calcium phosphate-containing experimental dental restorative materials was examined. The possible correlation of ion release with initial calcium content, solubility and degree of curing (degree of conversion) of examined materials was also investigated. Calcium release was measured with the use of an ion-selective electrode in an aqueous solution. Solubility was established by the weighing method. Raman spectroscopy was applied for the determination of the degree of conversion, while initial calcium content was examined with the use of energy-dispersive spectroscopy. For examined materials, the amount of calcium released was found to be positively correlated with solubility and initial calcium content. It was also found that the degree of conversion does not affect the ability of these experimental composites to release calcium ions.

  18. A simple diagnostic method for the differentiation of Tamm-Horsfall glycoproteins from healthy probands and those from recurrent calcium oxalate renal stone formers.

    PubMed

    Schnierle, P

    1995-11-15

    Tamm-Horsfall glycoproteins (THPs)* from healthy probands, and those from a majority of recurrent calcium oxalate renal stone formers, reveal different properties when analyzed using isoelectric focusing. The pl-values of THPs from healthy probands are approximately 3.5 while THPs from recurrent renal stone formers have pl-values between 4.5 and 6. The two groups of THPs exhibit completely different protein patterns in IEF. This proves the structural difference of these THPs. The differences in IEF analysis allow the differentiation between THPs from healthy probands and those from recurrent calcium oxalate stone formers. These differences could possibly be used as a simple diagnostic method for the recognition of recurrent calcium oxalate renal stone formers.

  19. Solubility, inhibition of crystallization and microscopic analysis of calcium oxalate crystals in the presence of fractions from Humulus lupulus L.

    NASA Astrophysics Data System (ADS)

    Frąckowiak, Anna; Koźlecki, Tomasz; Skibiński, PrzemysŁaw; GaweŁ, WiesŁaw; Zaczyńska, Ewa; Czarny, Anna; Piekarska, Katarzyna; Gancarz, Roman

    2010-11-01

    Procedures for obtaining noncytotoxic and nonmutagenic extracts from Humulus lupulus L. of high potency for inhibition and dissolving of model (calcium oxalate crystals) and real kidney stones, obtained from patients after surgery, are presented. Multistep extraction procedures were performed in order to obtain the preparations with the highest calcium complexing properties. The composition of obtained active fractions was analyzed by GC/MS and NMR methods. The influence of preparations on inhibition of formation and dissolution of model and real kidney stones were evaluated based on conductrometric titration, flame photometry and microscopic analysis. The "fraction soluble in methanol" obtained from water-alkaline extracts contains sugar alcohols and organic acids, and is effective in dissolving the kidney stones. The "fraction insoluble in methanol" contains only sugar derivatives and it changes the morphology of the crystals, making them "jelly-like". Both fractions are potentially effective in kidney stone therapy.

  20. Herbal extracts of Tribulus terrestris and Bergenia ligulata inhibit growth of calcium oxalate monohydrate crystals in vitro

    NASA Astrophysics Data System (ADS)

    Joshi, V. S.; Parekh, B. B.; Joshi, M. J.; Vaidya, A. B.

    2005-02-01

    A large number of people in this world are suffering from urinary stone problem. Calcium oxalate monohydrate (COM) and calcium oxalate dihydrate (COD) containing stones (calculi) are commonly found. In the present study, COM crystals were grown by a double diffusion gel growth technique using U-tubes. The gel was prepared from hydrated sodium metasilicate solution. The gel framework acts like a three-dimensional crucible in which the crystal nuclei are delicately held in the position of their formation, and nutrients are supplied for the growth. This technique can be utilized as a simplified screening static model to study the growth, inhibition and dissolution of urinary stones in vitro. The action of putative litholytic medicinal plants, Tribulus terrestris Linn. ( T.t) and Bergenia ligulata Linn. ( B.l.), has been studied in the growth of COM crystals. Tribulus terrestris and Bergenia ligulata are commonly used as herbal medicines for urinary calculi in India. To verify the inhibitive effect, aqueous extracts of Tribulus terrestris and Bergenia ligulata were added along with the supernatant solutions. The growth was measured and compared, with and without the aqueous extracts. Inhibition of COM crystal growth was observed in the herbal extracts. Maximum inhibition was observed in Bergenia ligulata followed by Tribulus terrestris. The results are discussed.

  1. An oxalyl-CoA dependent pathway of oxalate catabolism plays a role in regulating calcium oxalate crystal accumulation and defending against oxalate-secreting phytopathogens in Medicago truncatula

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Considering the widespread occurrence of oxalate in nature and its broad impact on a host of organisms, it is surprising that so little is known about the turnover of this important acid. In plants, oxalate oxidase is the most well studied enzyme capable of degrading oxalate, but not all plants pos...

  2. Preventive effect of some substances on experimental oxalic calculogenesis in the frog.

    PubMed

    Sorrentino, F; Fella, A; Pota, A

    1981-01-01

    Rana esculenta tadpoles that are fed spinach develop an oxalic calculogenesis. The addition of cholestyramine, orthophosphate, citrate, allopurinol and tungstate to the tank water prevented calculi formation while succinimide, magnesium oxide, hydrochlorothiazide and tetracycline were ineffective. Methylene blue proved lethal to tadpoles, and its anti-lithogenic activity could not be assessed. These findings, except for the non-effectiveness of magnesium oxide, are in agreement with both the theoretical expectations and the results obtained in other experimental models. Experimental frog calculogenesis seems to be a simple and valid method for evaluating anti-lithogenic activity.

  3. Magnesium hydrogen carbonate natural mineral water enriched with K(+)-citrate and vitamin B6 improves urinary abnormalities in patients with calcium oxalate nephrolithiasis.

    PubMed

    Bren, A; Kmetec, A; Kveder, R; Kaplan-Pavlovcic, S

    1998-01-01

    The influence of drinking magnesium hydrogen carbonate natural mineral water enriched with potassium citrate on urinary metabolic abnormalities was prospectively studied in 27 patients with recurrent calcium oxalate nephrolithiasis. The mean 24-hour urinary pH shifted from 6.34 to 6.93 (p < 0.01), the mean urinary magnesium/urinary creatinine ratio rose from 0.47 to 0.67 (p < 0.01), the mean urinary citrate/urinary creatinine ratio increased from 0.26 to 0.35 (p NS), and the mean 24-hour urinary calcium decreased from 7.98 to 6.05 mmol (p < 0.05). The effects of magnesium hydrogen carbonate natural mineral water enriched with potassium citrate were found to be favorable on urinary calcium, urinary magnesium/urinary creatinine ratio and urinary pH in patients with calcium oxalate nephrolithiasis.

  4. An assessment of engineered calcium oxalate crystal formation on plant growth and development as a step toward evaluating its use to enhance plant defense

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The establishment of new approaches to control chewing insects has been sought not only for direct use in reducing crop loss but also in managing resistance to the pesticides already in use. Engineered formation of calcium oxalate crystals is a potential strategy that could be developed to fulfill ...

  5. Oxygen nano-bubble water reduces calcium oxalate deposits and tubular cell injury in ethylene glycol-treated rat kidney.

    PubMed

    Hirose, Yasuhiko; Yasui, Takahiro; Taguchi, Kazumi; Fujii, Yasuhiro; Niimi, Kazuhiro; Hamamoto, Shuzo; Okada, Atsushi; Kubota, Yasue; Kawai, Noriyasu; Itoh, Yasunori; Tozawa, Keiichi; Sasaki, Shoichi; Kohri, Kenjiro

    2013-08-01

    Renal tubular cell injury induced by oxalate plays an important role in kidney stone formation. Water containing oxygen nano-bubbles (nanometer-sized bubbles generated from oxygen micro-bubbles; ONB) has anti-inflammatory effects. Therefore, we investigated the inhibitory effects of ONB water on kidney stone formation in ethylene glycol (EG)-treated rats. We divided 60 rats, aged 4 weeks, into 5 groups: control, the water-fed group; 100 % ONB, the 100 % ONB water-fed group; EG, the EG treated water-fed group; EG + 50 % ONB and EG + 100 % ONB, water containing EG and 50 % or 100 % ONB, respectively. Renal calcium oxalate (CaOx) deposition, urinary excretion of N-acetyl-β-D-glucosaminidase (NAG), and renal expression of inflammation-related proteins, oxidative stress biomarkers, and the crystal-binding molecule hyaluronic acid were compared among the 5 groups. In the control and 100 % ONB groups, no renal CaOx deposits were detected. In the EG + 50 % ONB and EG + 100 % ONB groups, ONB water significantly decreased renal CaOx deposits, urinary NAG excretion, and renal monocyte chemoattractant protein-1, osteopontin, and hyaluronic acid expression and increased renal superoxide dismutase-1 expression compared with the EG group. ONB water substantially affected kidney stone formation in the rat kidney by reducing renal tubular cell injury. ONB water is a potential prophylactic agent for kidney stones.

  6. Biosynthesis of l-Ascorbic Acid and Conversion of Carbons 1 and 2 of l-Ascorbic Acid to Oxalic Acid Occurs within Individual Calcium Oxalate Crystal Idioblasts1

    PubMed Central

    Kostman, Todd A.; Tarlyn, Nathan M.; Loewus, Frank A.; Franceschi, Vincent R.

    2001-01-01

    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 14C-labeled compounds and examined by micro-autoradiography for incorporation of 14C into calcium oxalate crystals. [14C]OxA gave heavy labeling of crystals, indicating the isolated idioblasts are functional in crystal formation. Incubation with [1-14C]AsA also gave heavy labeling of crystals, whereas [6-14C]AsA gave no labeling. Labeled precursors of AsA (l-[1-14C]galactose; d-[1-14C]mannose) also resulted in crystal labeling, as did the ascorbic acid analog, d-[1-14C]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. PMID:11161021

  7. Experimental tests of a homology model for OxlT, the oxalate transporter of Oxalobacter formigenes

    PubMed Central

    Yang, Qiang; Wang, Xicheng; Ye, Liwen; Mentrikoski, Mark; Mohammadi, Elham; Kim, Young-Mog; Maloney, Peter C.

    2005-01-01

    Using the x-ray structure of the glycerol 3-phosphate transporter (GlpT), we devised a model for the distantly related oxalate transporter, OxlT. The model accommodates all earlier biochemical information on OxlT, including the idea that Lys-355 lies on the permeation pathway, and predicts that Lys-355 and a second positive center, Arg-272, comprise the binding site for divalent oxalate. Study of R272K, R272A, and R272Q derivatives verifies that Arg-272 is essential, and comparisons with GlpT show that both anion transporters bind substrates within equivalent domains. In 22 single-cysteine variants in TM7 and TM8, topology as marked by accessibility to Oregon green maleimide is predicted by the model, with similar concordance for 52 positions probed earlier. The model also reconciles cross-linking of a cysteine pair placed near the periplasmic ends of TM2 and TM7, and retrospective study of TM2 and TM11 confirms that positions supporting disulfide trapping lie at a helical interface. Our work describes a pathway to the modeling of OxlT and other transporters in the major facilitator superfamily and outlines simple experimental tests to evaluate such proposals. PMID:15932938

  8. Experimental study of aluminum-oxalate complexing at 80 °C: Implications for the formation of secondary porosity within sedimentary reservoirs

    NASA Astrophysics Data System (ADS)

    Fein, Jeremy B.

    1991-10-01

    An experimental study of aluminum-oxalate complexing at 80 °C indicates that the presence of oxalate in sedimentary basin fluids may play an important role in creating secondary porosity in reservoir rocks. The solubility of gibbsite was measured as a function of oxalate concentration. Geologically realistic oxalate concentrations were used in order to simulate the aluminum mobilities that occur in reservoir fluids. Although the stoichiometry of the important aluminum-oxalate species cannot be determined from these data, the results are used to quantify the minimum extent of aluminum-oxalate complexing that occurs in solution. Assuming that Al(Ox)33- is the only important aluminum-oxalate complex, the data limit the log of the dissociation constant of Al(Ox)33- to be ≤-16.5. Thermodynamic modeling of aluminum systems with fluids that contain NaCl, acetate, and oxalate illustrates that aluminum-oxalate complexing is much more important than aluminum-acetate complexing, even at relatively low oxalate concentrations and at very high acetate concentrations. In addition, these calculations show that aluminum-oxalate complexing can greatly increase aluminum mobility in formation waters and, therefore, may increase aluminosilicate mineral dissolution within sedimentary basin fluid-rock systems.

  9. Ultrastructural localization of calcium in peripheral nerve fibres undergoing Wallerian degeneration: an oxalate-pyroantimonate and X-ray microanalysis study.

    PubMed

    Martinez, A M; Ribeiro, L C

    1998-07-01

    Calcium was demonstrated ultrastructurally as an electron dense precipitate with the oxalate-pyroantimonate technique in rat sural nerves undergoing early Wallerian degeneration after surgical crush (30 h after lesion). In normal nerves (controls) the distribution of calcium precipitates in the axoplasm appeared homogeneous in unmyelinated fibres and heterogeneous (with specific domains) in myelinated ones. Calcium precipitate was also found within the smooth reticulum and mitochondria of the fibers and Schwann cells, and in endoneurial space. In nerve fibres with early degenerative alterations, there was increased calcium precipitate within membranous profiles of smooth reticulum and mitochondria (in both nerve fibres and Schwann cells) and in areas where the cytoskeletal proteins were disintegrated. This last finding confirms the participation of calcium in the disruption of axonal microtubules and neurofilaments in early Wallerian degeneration process. Fibers with intense degenerative changes lost the usual distribution for calcium. The specificity of the reaction was demonstrated using EGTA chelation and X-ray microanalysis.

  10. High-throughput platform for design and screening of peptides as inhibitors of calcium oxalate monohydrate crystallization

    NASA Astrophysics Data System (ADS)

    Farmanesh, Sahar; Chung, Jihae; Chandra, Divya; Sosa, Ricardo D.; Karande, Pankaj; Rimer, Jeffrey D.

    2013-06-01

    Crystal growth modifiers present a versatile tool for controlling crystal shape and size. Our work described here focuses on the design and screening of short peptides as inhibitors of calcium oxalate monohydrate (COM) crystals using high-throughput approaches. We designed a small library of 13 peptides containing Ala and Asp amino acids arranged in varying sequences that mimic ubiquitous motifs in natural calcium-binding proteins. Peptides were screened using a quick assay to measure their efficacy for inhibiting COM crystallization. Our results show that subtle variations in the placement of Ala and Asp residues in the peptide sequence can have a profound effect on their inhibition potential. We were able to discover peptide sequences that inhibit COM crystallization more effectively than some of the well-known COM inhibitors, such as citrate. Our results also demonstrate that peptides can be engineered to bind to specific faces of COM crystals. Peptide sequences identified in this work are promising candidates for further development as therapies for biomineral-related diseases, such as kidney stone disease. Collectively, our work establishes new paradigms for the design, synthesis, and screening of peptides for controlling crystal habit with the potential to impact a variety of fields, including drug discovery, advanced materials, catalysis and separations.

  11. A comparison of the binding of urinary calcium oxalate monohydrate and dihydrate crystals to human kidney cells in urine

    PubMed Central

    Wang, Tingting; Thurgood, Lauren A.; Grover, Phulwinder K.; Ryall, Rosemary L.

    2010-01-01

    Objective To compare the binding kinetics of urinary calcium oxalate monohydrate (COM) and dihydrate (COD) crystals to human kidney (HK-2) cells in ultra-filtered (UF), and centrifuged and filtered (CF) human urine; and to quantify the binding of COM and COD crystals to cultured HK-2 cells in UF and CF urine samples collected from different individuals. Materials and methods Urine was collected from healthy subjects, pooled, centrifuged and filtered. 14C-oxalate-labelled COM and COD crystals were precipitated from the urine by adding oxalate after adjustment of two aliquots of the urine to 2 and 8 mm Ca2+, respectively. For the kinetic study, the crystals were incubated with HK-2 cells for up to 120 min in pooled CF urine adjusted to 2 and 8 mm Ca2+. Identical experiments were also carried out in UF urine samples collected from the same individuals. For the quantitative study, the same radioactively labelled COM and COD crystals were incubated with HK-2 cells for 50 min in separate CF and UF urines collected from eight healthy individuals at the native Ca2+ concentrations of the urines. Field emission electron microscopy and Fourier transform-infrared spectroscopy were used to confirm crystal morphology. Results Binding of both COM and COD crystals generally bound more strongly at 8 mm than at 2 mm Ca2+. The kinetic binding curves of COM were smooth, while those of COD were consistently biphasic, suggesting that the two crystal types induce different cellular metabolic responses: HK-2 cells crystals appear to possess a transitory mechanism for detaching COD, but not COM crystals. In UF urine, COM binding was significantly greater than that of COD at 2 mm Ca2+, but at 8 mm Ca2+ the binding of COD was greater at early and late time points. COD also bound significantly more strongly at early time points in CF urine at both 2 and 8 mm Ca2+. In both CF and UF urine, there was no difference between the binding affinity of urinary COM and COD crystals. Conclusion

  12. Inhibition of Glycolate Oxidase With Dicer-substrate siRNA Reduces Calcium Oxalate Deposition in a Mouse Model of Primary Hyperoxaluria Type 1

    PubMed Central

    Dutta, Chaitali; Avitahl-Curtis, Nicole; Pursell, Natalie; Larsson Cohen, Marita; Holmes, Benjamin; Diwanji, Rohan; Zhou, Wei; Apponi, Luciano; Koser, Martin; Ying, Bo; Chen, Dongyu; Shui, Xue; Saxena, Utsav; Cyr, Wendy A; Shah, Anee; Nazef, Naim; Wang, Weimin; Abrams, Marc; Dudek, Henryk; Salido, Eduardo; Brown, Bob D; Lai, Chengjung

    2016-01-01

    Primary hyperoxaluria type 1 (PH1) is an autosomal recessive, metabolic disorder caused by mutations of alanine-glyoxylate aminotransferase (AGT), a key hepatic enzyme in the detoxification of glyoxylate arising from multiple normal metabolic pathways to glycine. Accumulation of glyoxylate, a precursor of oxalate, leads to the overproduction of oxalate in the liver, which accumulates to high levels in kidneys and urine. Crystalization of calcium oxalate (CaOx) in the kidney ultimately results in renal failure. Currently, the only treatment effective in reduction of oxalate production in patients who do not respond to high-dose vitamin B6 therapy is a combined liver/kidney transplant. We explored an alternative approach to prevent glyoxylate production using Dicer-substrate small interfering RNAs (DsiRNAs) targeting hydroxyacid oxidase 1 (HAO1) mRNA which encodes glycolate oxidase (GO), to reduce the hepatic conversion of glycolate to glyoxylate. This approach efficiently reduces GO mRNA and protein in the livers of mice and nonhuman primates. Reduction of hepatic GO leads to normalization of urine oxalate levels and reduces CaOx deposition in a preclinical mouse model of PH1. Our results support the use of DsiRNA to reduce liver GO levels as a potential therapeutic approach to treat PH1. PMID:26758691

  13. The role of interfacial chemistry in surface nucleation and growth of calcium oxalate

    SciTech Connect

    Song, L.; Campbell, A.A.; Bunker, B.C.

    1993-06-01

    The surface adsorption of Ca{sup 2+} and oxalate anions (Ox{sup 2{minus}}) on SiO{sub 2}, TiO{sub 2} and Al{sub 2}O{sub 3} oxide colloids were by electrosonic amplitude measurements. Kinetics studies of CaO{sub x} formation on the model oxide surfaces were carried out using constant composition method. Results suggested Ca{sup 2+} and Ox{sup 2{minus}} adsorptiopn was promoted on the oxide surfaces with opposite charges, and the specific adsorption of the divalent ions also resulted in surface charge reversal. For heterogeous nucleation of CaO{sub x} on the three model oxide surfaces, induction times ranged from 270 to 360 minutes compared with 1200 minutes estimated for homogeneous nucleation and 700 minutes for spontaneous or nucleation at pH 6.5 and S = 3.3. Lower nucleation barriers, 27 mJ/m{sup 2} for SiO{sub 2}, 26 mJ/m{sup 2} for TiO{sub 2}, were observed by studying the dependence of nucleation induction times as the function of solution supersaturation.

  14. Alpha-enolase on apical surface of renal tubular epithelial cells serves as a calcium oxalate crystal receptor

    NASA Astrophysics Data System (ADS)

    Fong-Ngern, Kedsarin; Thongboonkerd, Visith

    2016-10-01

    To search for a strategy to prevent kidney stone formation/recurrence, this study addressed the role of α-enolase on apical membrane of renal tubular cells in mediating calcium oxalate monohydrate (COM) crystal adhesion. Its presence on apical membrane and in COM crystal-bound fraction was confirmed by Western blotting and immunofluorescence staining. Pretreating MDCK cells with anti-α-enolase antibody, not isotype-controlled IgG, dramatically reduced cell-crystal adhesion. Immunofluorescence staining also confirmed the direct binding of purified α-enolase to COM crystals at {121} > {100} > {010} crystal faces. Coating COM crystals with urinary proteins diminished the crystal binding capacity to cells and purified α-enolase. Moreover, α-enolase selectively bound to COM, not other crystals. Chemico-protein interactions analysis revealed that α-enolase interacted directly with Ca2+ and Mg2+. Incubating the cells with Mg2+ prior to cell-crystal adhesion assay significantly reduced crystal binding on the cell surface, whereas preincubation with EDTA, a divalent cation chelator, completely abolished Mg2+ effect, indicating that COM and Mg2+ competitively bind to α-enolase. Taken together, we successfully confirmed the role of α-enolase as a COM crystal receptor to mediate COM crystal adhesion at apical membrane of renal tubular cells. It may also serve as a target for stone prevention by blocking cell-crystal adhesion and stone nidus formation.

  15. A study on calcium oxalate crystals in Tinantia anomala (Commelinaceae) with special reference to ultrastructural changes during anther development.

    PubMed

    Gębura, Joanna; Winiarczyk, Krystyna

    2016-07-01

    Calcium oxalate (CaOx) crystals in higher plants occur in five forms: raphides, styloids, prisms, druses, and crystal sand. CaOx crystals are formed in almost all tissues in intravacuolar crystal chambers. However, the mechanism of crystallization and the role of CaOx crystals have not been clearly explained. The aim of this study was to explore the occurrence and location of CaOx crystals in organs of Tinantia anomala (Torr.) C.B. Clarke (Commelinaceae) with special attention to ultrastructural changes in the quantity of tapetal raphides during microsporogenesis. We observed various parts of the plant, that is, stems, leaves, sepals, petals, anthers, staminal trichomes and stigmatic papillae and identified CaOx crystals in all parts except staminal trichomes and stigmatic papillae in Tinantia anomala. Three morphological forms: styloids, raphides and prisms were found in different amounts in different parts of the plant. Furthermore, in this species, we identified tapetal raphides in anthers. The number of tapetal raphides changed during microsporogenesis. At the beginning of meiosis, the biosynthesis of raphides proceeded intensively in the provacuoles. These organelles were formed from the endoplasmic reticulum system. In the tetrad stage, we observed vacuoles with needle-shaped raphides (type I) always localised in the centre of the organelle. When the amoeboid tapetum was degenerating, vacuoles also began to fade. We observed a small number of raphides in the stage of mature pollen grains.

  16. Occurrence and characterisation of calcium oxalate crystals in stems and fruits of Hylocereus costaricensis and Selenicereus megalanthus (Cactaceae: Hylocereeae).

    PubMed

    Viñas, María; Jiménez, Víctor M

    2016-10-01

    Detailed description about occurrence of calcium oxalate (CaOx) crystals in the edible vine cactus species Hylocereus costaricensis and Selenicereus megalanthus is scarce. Therefore, we evaluated and characterized the presence, morphology and composition of CaOx crystals in both species. Crystals were isolated from greenhouse and in vitro vegetative stems, and from ripe fruit peels and pulp by enzymatic digestion and density centrifugation and quantified with a haemocytometer. Morphologies were studied using scanning electron microscopy, elemental composition with energy-dispersive X-ray spectroscopy and salt composition with X-ray powder diffraction. Analyses conducted confirmed that isolated crystals were exclusively composed by CaOx, both mono- and dihydrated. Highest crystal contents were measured in greenhouse stems, followed by the fruit peels. While very few crystals were quantified in in vitro plants, they were not detected in the fruit pulp at all, which is of advantage for its human consumption and could be linked to mechanisms of seed dispersal through animals. Different crystal morphologies were observed, sometimes varying between genotypes and tissues analysed. This is the first work known to the authors with a detailed characterization of CaOx crystals in vine cacti.

  17. Study of polymeric additive effect on calcium oxalate dihydrate crystal growth using real-time atomic force microscopy

    NASA Astrophysics Data System (ADS)

    Jung, Taesung; Kim, Jong-Nam; Kim, Woo-Sik; Kyun Choi, Chang

    2011-07-01

    Microscopic events associated with crystal growth and characterization of the growth hillocks on the (1 0 0) and (1 0 1) faces of COD were examined by atomic force microscopy. The (1 0 0) and (1 0 1) faces of COD developed elliptical and triangular hillocks and pits, respectively. Each face exhibited hillocks with step sites that can be assigned to specific crystal planes, enabling direct determination of the growth rates along specific crystallographic directions. The addition of macromolecules with anionic side chains, poly- L-aspartate, poly- L-glutamate, and polyacrylate resulted in inhibition of growth on the hillock step planes. The magnitude of their effect depended on the macromolecule structures and identity of the step site. The isotropic shape of the COD hillocks mimicked the shape of the resulting macroscopic COD crystals based on step-specific binding of the macromolecules to the COD crystal, with stronger step pinning along the [0 1 0] direction than in the [0 0 1] direction. Electrostatic matching between the crystal faces and additives according to the ionic array of calcium oxalate in the COD structure was found to be responsible for the preferential binding of the macromolecules to terraces.

  18. Experimental models of renal calcium stones in rodents

    PubMed Central

    Bilbault, Héloïse; Haymann, Jean-Philippe

    2016-01-01

    In human nephrolithiasis, most stones are containing calcium and are located within urinary cavities; they may contain monohydrate calcium oxalate, dihydrate calcium oxalate and/or calcium phosphates in various proportion. Nephrolithiasis may also be associated with nephrocalcinosis, i.e., crystal depositions in tubular lumen and/or interstitium, an entity which suggests specific pathological processes. Several rodents models have been developed in order to study the pathophysiology of intrarenal crystal formation. We review here calcium rodent models classified upon the presence of nephrolithiasis and/or nephrocalcinosis. As rodents are not prone to nephrolithiasis, models require the induction of a long standing hypercalciuria or hyperoxaluria (thus explaining the very few studies reported), conversely to nephrocalcinosis which may occur within hours or days. Whereas a nephrotoxicity leading to tubular injury and regeneration appears as a critical event for crystal retention in nephrocalcinosis models, surprisingly very little is known about the physiopathology of crystal attachment to urothelium in nephrolithiasis. Creating new models of nephrolithiasis especially in different genetic mice strains appears an important challenge in order to unravel the early mechanisms of urinary stone formation in papilla and fornices. PMID:26981444

  19. Calcium oxalate crystal production and density at different phenological stages of soybean plants (Glycine max L.) from the southeast of the Pampean Plain, Argentina.

    PubMed

    Borrelli, N; Benvenuto, M L; Osterrieth, M

    2016-11-01

    Glycine max L. (soybean) is one of the major crops of the world. Although the process of biomineralisation has been reported in some organs of soybean, we now report the description and quantification of calcium oxalate crystals in vegetative and reproductive organs of soybean during its life cycle, as they act as an important source of calcium to the soil, once the harvesting is finished. Through diaphanisation, cross-sectioning, optical and scanning electron microscopy analysis of the organs, morphology, size and location of the crystals were identified. In addition, crystal density (n° crystals·mm(-2) ) and the input of crystals to soil (n° crystals·ha(-1) ) were calculated. Soybean produced prismatic calcium oxalate crystals in vegetative and reproductive organs, generally associated with vascular bundles, resulting in a potencial transfer to the soil of 81.4 x 10(7) crystals·ha(-1) throughout its life cycle. Pods were the organs with higher calcium oxalate crystal production (1112.7 ± 384.6 crystals·mm(-2) ), but with the smaller size (12.3 ± 2.1 μm long). However, cotyledons were the organs that produce the larger crystals (21.3 ± 3.5 μm long), but in lesser amounts (150.9 ± 64.4 crystals·mm(-2) ). In leaves, although crystal size did not differ from vegetative to reproductive stage (14.5 ± 4.2 and 14.5 ± 4 μm in length, respectively), the crystal density increased (293.2 and 409 crystals·mm(-2) , respectively). These results will contribute to knowledge of the amount of calcium oxalate crystals involved in the process of Ca recycling through cultivated vegetation in fields from humid plains at medium latitudes, which therefore have biological, botanical, biogeochemical and pedological relevance.

  20. Micro-CT observations of the 3D distribution of calcium oxalate crystals in cotyledons during maturation and germination in Lotus miyakojimae seeds.

    PubMed

    Yamauchi, Daisuke; Tamaoki, Daisuke; Hayami, Masato; Takeuchi, Miyuki; Karahara, Ichirou; Sato, Mayuko; Toyooka, Kiminori; Nishioka, Hiroshi; Terada, Yasuko; Uesugi, Kentaro; Takano, Hidekazu; Kagoshima, Yasushi; Mineyuki, Yoshinobu

    2013-06-01

    The cotyledon of legume seeds is a storage organ that provides nutrients for seed germination and seedling growth. The spatial and temporal control of the degradation processes within cotyledons has not been elucidated. Calcium oxalate (CaOx) crystals, a common calcium deposit in plants, have often been reported to be present in legume seeds. In this study, micro-computed tomography (micro-CT) was employed at the SPring-8 facility to examine the three-dimensional distribution of crystals inside cotyledons during seed maturation and germination of Lotus miyakojimae (previously Lotus japonicus accession Miyakojima MG-20). Using this technique, we could detect the outline of the embryo, void spaces in seeds and the cotyledon venation pattern. We found several sites that strongly inhibited X-ray transmission within the cotyledons. Light and polarizing microscopy confirmed that these areas corresponded to CaOx crystals. Three-dimensional observations of dry seeds indicated that the CaOx crystals in the L. miyakojimae cotyledons were distributed along lateral veins; however, their distribution was limited to the abaxial side of the procambium. The CaOx crystals appeared at stage II (seed-filling stage) of seed development, and their number increased in dry seeds. The number of crystals in cotyledons was high during germination, suggesting that CaOx crystals are not degraded for their calcium supply. Evidence for the conservation of CaOx crystals in cotyledons during the L. miyakojimae germination process was also supported by the biochemical measurement of oxalic acid levels.

  1. OXALATE DEPOSITION ON ASBESTOS BODIES

    EPA Science Inventory

    The clinical and histopathologic findings in three patients with a deposition of calcium oxalate crystals on ferruginous bodies after occupational exposure to asbestos are provided. In addition, we test the hypothesis that this oxalate can be generated through a nonenzymatic o...

  2. Oxalate content of cereals and cereal products.

    PubMed

    Siener, Roswitha; Hönow, Ruth; Voss, Susanne; Seidler, Ana; Hesse, Albrecht

    2006-04-19

    Detailed knowledge of food oxalate content is of essential importance for dietary treatment of recurrent calcium oxalate urolithiasis. Dietary oxalate can contribute considerably to the amount of urinary oxalate excretion. Because cereal foods play an important role in daily nutrition, the soluble and total oxalate contents of various types of cereal grains, milling products, bread, pastries, and pasta were analyzed using an HPLC-enzyme-reactor method. A high total oxalate content (>50 mg/100 g) was found in whole grain wheat species Triticum durum (76.6 mg/100 g), Triticum sativum (71.2 mg/100 g), and Triticum aestivum (53.3 mg/100 g). Total oxalate content was comparably high in whole grain products of T. aestivum, that is, wheat flakes and flour, as well as in whole grain products of T. durum, that is, couscous, bulgur, and pasta. The highest oxalate content was demonstrated for wheat bran (457.4 mg/100 g). The higher oxalate content in whole grain than in refined grain cereals suggests that oxalic acid is primarily located in the outer layers of cereal grains. Cereals and cereal products contribute to the daily oxalate intake to a considerable extent. Vegetarian diets may contain high amounts of oxalate when whole grain wheat and wheat products are ingested. Recommendations for prevention of recurrence of calcium oxalate stone disease have to take into account the oxalate content of these foodstuffs.

  3. Irritant contact dermatitis caused by needle-like calcium oxalate crystals, raphides, in Agave tequilana among workers in tequila distilleries and agave plantations.

    PubMed

    Salinas, M L; Ogura, T; Soffchi, L

    2001-02-01

    It was found that needle-like calcium oxalate crystals, raphides, are found abundantly in all tissues of Agave tequilana plants; thus, 1 droplet (0.03 ml) of juice pressed from leaves contains 100-150 crystals, 30-500 microm in length, sharpened at both ends. In tequila distilleries, 5/6 of the workers who handle the agave stems have experienced the characteristic irritation. In contrast, only 1/3 of workers in agave plantations who harvest agave plants, complain of the irritation. It is confirmed that all the irritation suffered in both distilleries and plantations takes place at bodily locations where the plants come into contact with the worker's skin in the course of their work.

  4. Analysis of Altered MicroRNA Expression Profiles in Proximal Renal Tubular Cells in Response to Calcium Oxalate Monohydrate Crystal Adhesion: Implications for Kidney Stone Disease

    PubMed Central

    Wang, Bohan; Wu, Bolin; Liu, Jun; Yao, Weimin; Xia, Ding; Li, Lu; Chen, Zhiqiang; Ye, Zhangqun; Yu, Xiao

    2014-01-01

    Background Calcium oxalate monohydrate (COM) is the major crystalline component in kidney stones and its adhesion to renal tubular cells leads to tubular injury. However, COM-induced toxic effects in renal tubular cells remain ambiguous. MicroRNAs (miRNAs) play an important role in gene regulation at the posttranscriptional levels. Objective The present study aimed to assess the potential changes in microRNAs of proximal renal tubular cells in response to the adhesion of calcium oxalate monohydrate (COM) crystals. Methodology Lactate dehydrogenase (LDH) activity and DAPI staining were used to measure the toxic effects of HK-2 cells exposed to COM crystals. MicroRNA microarray and mRNA microarray were applied to evaluate the expression of HK-2 cells exposed to COM crystals. Quantitative real-time PCR (qRT-PCR) technology was used to validate the microarray results. Target prediction, Gene Ontology (GO) analysis and pathway analysis were applied to predict the potential roles of microRNAs in biological processes. Principal Findings Our study showed that COM crystals significantly altered the global expression profile of miRNAs in vitro. After 24 h treatment with a dose (1 mmol/L), 25 miRNAs were differentially expressed with a more than 1.5-fold change, of these miRNAs, 16 were up-regulated and 9 were down-regulated. A majority of these differentially expressed miRNAs were associated with cell death, mitochondrion and metabolic process. Target prediction and GO analysis suggested that these differentially expressed miRNAs potentially targeted many genes which were related to apoptosis, regulation of metabolic process, intracellular signaling cascade, insulin signaling pathway and type 2 diabetes. Conclusion Our study provides new insights into the role of miRNAs in the pathogenesis associated with nephrolithiasis. PMID:24983625

  5. Urinary calcium and oxalate excretion in healthy adult cats are not affected by increasing dietary levels of bone meal in a canned diet.

    PubMed

    Passlack, Nadine; Zentek, Jürgen

    2013-01-01

    This study aimed to investigate the impact of dietary calcium (Ca) and phosphorus (P), derived from bone meal, on the feline urine composition and the urinary pH, allowing a risk assessment for the formation of calcium oxalate (CaOx) uroliths in cats. Eight healthy adult cats received 3 canned diets, containing 12.2 (A), 18.5 (B) and 27.0 g Ca/kg dry matter (C) and 16.1 (A), 17.6 (B) and 21.1 g P/kg dry matter (C). Each diet was fed over 17 days. After a 7 dayś adaptation period, urine and faeces were collected over 2×4 days (with a two-day rest between), and blood samples were taken. Urinary and faecal minerals, urinary oxalate (Ox), the urinary pH and the concentrations of serum Ca, phosphate and parathyroid hormone (PTH) were analyzed. Moreover, the urine was microscopically examined for CaOx uroliths. The results demonstrated that increasing levels of dietary Ca led to decreased serum PTH and Ca and increased faecal Ca and P concentrations, but did not affect the urinary Ca or Ox concentrations or the urinary fasting pH. The urinary postprandial pH slightly increased when the diet C was compared to the diet B. No CaOx crystals were detected in the urine of the cats. In conclusion, urinary Ca excretion in cats seems to be widely independent of the dietary Ca levels when Ca is added as bone meal to a typical canned diet, implicating that raw materials with higher contents of bones are of subordinate importance as risk factors for the formation of urinary CaOx crystals.

  6. [Kinetics of the growth of Ca oxalate crystals from supersaturated solutions].

    PubMed

    Leskovar, P; Hartung, R

    1979-04-01

    Several factors influencing the nucleation and growth of Ca-oxalate crystals from metastable and instable solutions were studied in some detail. Factors of interest were the absolute concentration of calcium respectively oxalate, the quotient oxalate/calcium, repeated additions of calcium and/or oxalate, the presence or absence of crystal seeds, the agitation respectively stagnation of the metastable Ca-oxalate solution, the duration of crystallization, etc. The striking findings are the eminent role of oxalate in the formation of big crystals and crystal aggregates, the distinct inhibition of crystal growth at higher and very high calcium concentrations, as well as the substantial crystal enlargement at the presistent oxalate load.

  7. Metabolomics analysis for hydroxy-L-proline-induced calcium oxalate nephrolithiasis in rats based on ultra-high performance liquid chromatography quadrupole time-of-flight mass spectrometry

    PubMed Central

    Gao, Songyan; Yang, Rui; Peng, Zhongjiang; Lu, Hongtao; Li, Na; Ding, Jiarong; Cui, Xingang; Chen, Wei; Dong, Xin

    2016-01-01

    About 80% of kidney stones are composed of calcium oxalate (CaOx) with variable amounts of calcium phosphate, and hyperoxaluria is considered as an important factor of CaOx nephrolithiasis. However, the underlying metabolic mechanisms of CaOx nephrolithiasis remain undefined. In this study, we successfully developed a rat model with hydroxy-L-proline (HLP) -induced CaOx nephrolithiasis. Rats were continuously orally administrated with HLP for 28 days. Urine and blood samples were collected from the rats treated with or without HLP at four different time points. UPLC–Q-TOF/MS was applied to profile the abundances of metabolites. To obtain more comprehensive analysis of metabolic profiling spectrum, combination of RP-LC and HILIC were applied. We identify 42 significant differential metabolites in the urine, and 13 significant differential metabolites in the blood. Pathway analysis revealed that the pathways involved in amino acid metabolism, taurine metabolism, bile acid synthesis, energy metabolism, TCA cycle, purine metabolism, vitamin metabolism, nicotinic acid and nicotinamide metabolism have been modulated by HLP treatment. This study suggested that a number of metabolic pathways are dysfunctional in the HLP induced crystal kidney injury, and further studies on those pathways are warranted to better understand the metabolic mechanism of CaOx nephrolithiasis. PMID:27443631

  8. Effect of dietary moisture and sodium content on urine composition and calcium oxalate relative supersaturation in healthy miniature schnauzers and labrador retrievers.

    PubMed

    Stevenson, A E; Hynds, W K; Markwell, P J

    2003-04-01

    The aim of this series of studies was to evaluate two possible feeding strategies as methods for reducing the risk of calcium oxalate (CaOx) formation in two breeds of healthy dog. The studies compared the effect of dietary moisture (Study 1) and dietary sodium (Na), (Study 2) on urine composition of labrador retrievers (LR) and miniature schnauzers (MS). A nutritionally complete dry dog food was fed to 16 dogs (eight LR, eight MS; Study 1) and 15 dogs (seven LR, eight MS; Study 2) for 24 days (Study 1), or 36 days (Study 2). The dogs were fed the diet alone (7% moisture, 0.06 g Na/100 kcal), or supplemented with deionised water to 73% moisture (Study 1), or dietary Na, to deliver 0.20 or 0.30 g Na per 100 kcal (Study 2). Urine pH, volume, specific gravity, and concentrations of 12 analytes were measured for each dog. Urinary relative supersaturations (RSS) with CaOx were calculated from these values. The effects of supplemental Na or water were established using t tests (Study 1) or analysis of variance, and multiple range tests (least significant difference) (Study 2); P<0.05 was considered significant. Increasing dietary moisture significantly increased total moisture intake (P=0.001), and reduced urine specific gravity (P=0.003), urinary oxalate concentration (P=0.04), and CaOx relative supersaturation (P=0.04) in the MS. Urinary parameters remained unchanged in the LR, indicating that feeding a high moisture diet may reduce the risk of CaOx formation in high-risk breeds. Increasing dietary Na led to production of urine with a significantly lower CaOx RSS in both breeds, indicating that sodium supplementation to dry diet formats may reduce the risk of CaOx formation. These feeding strategies should be considered when evaluating methods for preventing CaOx formation within high-risk groups.

  9. Estimation of the oxalate content of foods and daily oxalate intake

    NASA Technical Reports Server (NTRS)

    Holmes, R. P.; Kennedy, M.

    2000-01-01

    BACKGROUND: The amount of oxalate ingested may be an important risk factor in the development of idiopathic calcium oxalate nephrolithiasis. Reliable food tables listing the oxalate content of foods are currently not available. The aim of this research was to develop an accurate and reliable method to measure the food content of oxalate. METHODS: Capillary electrophoresis (CE) and ion chromatography (IC) were compared as direct techniques for the estimation of the oxalate content of foods. Foods were thoroughly homogenized in acid, heat extracted, and clarified by centrifugation and filtration before dilution in water for analysis. Five individuals consuming self-selected diets maintained food records for three days to determine their mean daily oxalate intakes. RESULTS: Both techniques were capable of adequately measuring the oxalate in foods with a significant oxalate content. With foods of very low oxalate content (<1.8 mg/100 g), IC was more reliable than CE. The mean daily intake of oxalate by the five individuals tested was 152 +/- 83 mg, ranging from 44 to 352 mg/day. CONCLUSIONS: CE appears to be the method of choice over IC for estimating the oxalate content of foods with a medium (>10 mg/100 g) to high oxalate content due to a faster analysis time and lower running costs, whereas IC may be better suited for the analysis of foods with a low oxalate content. Accurate estimates of the oxalate content of foods should permit the role of dietary oxalate in urinary oxalate excretion and stone formation to be clarified. Other factors, apart from the amount of oxalate ingested, appear to exert a major influence over the amount of oxalate excreted in the urine.

  10. Ozone-Induced Responses in Croton floribundus Spreng. (Euphorbiaceae): Metabolic Cross-Talk between Volatile Organic Compounds and Calcium Oxalate Crystal Formation

    PubMed Central

    Cardoso-Gustavson, Poliana; Bolsoni, Vanessa Palermo; de Oliveira, Debora Pinheiro; Guaratini, Maria Tereza Gromboni; Aidar, Marcos Pereira Marinho; Marabesi, Mauro Alexandre; Alves, Edenise Segala; de Souza, Silvia Ribeiro

    2014-01-01

    Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3. PMID:25165889

  11. Ozone-induced responses in Croton floribundus Spreng. (Euphorbiaceae): metabolic cross-talk between volatile organic compounds and calcium oxalate crystal formation.

    PubMed

    Cardoso-Gustavson, Poliana; Bolsoni, Vanessa Palermo; de Oliveira, Debora Pinheiro; Guaratini, Maria Tereza Gromboni; Aidar, Marcos Pereira Marinho; Marabesi, Mauro Alexandre; Alves, Edenise Segala; de Souza, Silvia Ribeiro

    2014-01-01

    Here, we proposed that volatile organic compounds (VOC), specifically methyl salicylate (MeSA), mediate the formation of calcium oxalate crystals (COC) in the defence against ozone (O3) oxidative damage. We performed experiments using Croton floribundus, a pioneer tree species that is tolerant to O3 and widely distributed in the Brazilian forest. This species constitutively produces COC. We exposed plants to a controlled fumigation experiment and assessed biochemical, physiological, and morphological parameters. O3 induced a significant increase in the concentrations of constitutive oxygenated compounds, MeSA and terpenoids as well as in COC number. Our analysis supported the hypothesis that ozone-induced VOC (mainly MeSA) regulate ROS formation in a way that promotes the opening of calcium channels and the subsequent formation of COC in a fast and stable manner to stop the consequences of the reactive oxygen species in the tissue, indeed immobilising the excess calcium (caused by acute exposition to O3) that can be dangerous to the plant. To test this hypothesis, we performed an independent experiment spraying MeSA over C. floribundus plants and observed an increase in the number of COC, indicating that this compound has a potential to directly induce their formation. Thus, the tolerance of C. floribundus to O3 oxidative stress could be a consequence of a higher capacity for the production of VOC and COC rather than the modulation of antioxidant balance. We also present some insights into constitutive morphological features that may be related to the tolerance that this species exhibits to O3.

  12. Oxalate content of foods and its effect on humans.

    PubMed

    Noonan, S C; Savage, G P

    1999-03-01

    Oxalic acid and its salts occur as end products of metabolism in a number of plant tissues. When these plants are eaten they may have an adverse effect because oxalates bind calcium and other minerals. While oxalic acid is a normal end product of mammalian metabolism, the consumption of additional oxalic acid may cause stone formation in the urinary tract when the acid is excreted in the urine. Soaking and cooking of foodstuffs high in oxalate will reduce the oxalate content by leaching. The mean daily intake of oxalate in English diets has been calculated to be 70-150 mg, with tea appearing to contribute the greatest proportion of oxalate in these diets; rhubarb, spinach and beet are other common high oxalate-content foods. Vegetarians who consume greater amounts of vegetables will have a higher intake of oxalates, which may reduce calcium availability. This may be an increased risk factor for women, who require greater amounts of calcium in the diet. In humans, diets low in calcium and high in oxalates are not recommended but the occasional consumption of high oxalate foods as part of a nuritious diet does not pose any particular problem.

  13. Surface aggregation of urinary proteins and aspartic acid-rich peptides on the faces of calcium oxalate monohydrate investigated by in situ force microscopy

    SciTech Connect

    Weaver, M L; Qiu, S R; Hoyer, J R; Casey, W H; Nancollas, G H; De Yoreo, J J

    2008-05-28

    The growth of calcium oxalate monohydrate in the presence of Tamm-Horsfall protein (THP), osteopontin (OPN), and the 27-residue synthetic peptides (DDDS){sub 6}DDD and (DDDG){sub 6}DDD [where D = aspartic acid and X = S (serine) or G (glycine)] was investigated via in situ atomic force microscopy (AFM). The results show that these three growth modulators create extensive deposits on the crystal faces. Depending on the modulator and crystal face, these deposits can occur as discrete aggregates, filamentary structures, or uniform coatings. These proteinaceous films can lead to either the inhibition or increase of the step speeds (with respect to the impurity-free system) depending on a range of factors that include peptide or protein concentration, supersaturation and ionic strength. While THP and the linear peptides act, respectively, to exclusively increase and inhibit growth on the (-101) face, both exhibit dual functionality on the (010) face, inhibiting growth at low supersaturation or high modulator concentration and accelerating growth at high supersaturation or low modulator concentration. Based on analyses of growth morphologies and dependencies of step speeds on supersaturation and protein or peptide concentration, we argue for a picture of growth modulation that accounts for the observations in terms of the strength of binding to the surfaces and steps and the interplay of electrostatic and solvent-induced forces at crystal surface.

  14. Calcium oxalate crystals increased enolase-1 secretion from renal tubular cells that subsequently enhanced crystal and monocyte invasion through renal interstitium

    PubMed Central

    Chiangjong, Wararat; Thongboonkerd, Visith

    2016-01-01

    Calcium oxalate monohydrate (COM) crystals cause kidney stone disease by still unclear mechanisms. The present study aimed to characterize changes in secretion of proteins from basolateral compartment of renal tubular epithelial cells after exposure to COM crystals and then correlated them with the stone pathogenesis. Polarized MDCK cells were cultivated in serum-free medium with or without 100 μg/ml COM crystals for 20 h. Secreted proteins collected from the lower chamber (basolateral compartment) were then resolved in 2-D gels and visualized by Deep Purple stain (n = 5 gels/group). Spot matching and intensity analysis revealed six protein spots with significantly altered levels in COM-treated samples. These proteins were then identified by tandem mass spectrometry (Q-TOF MS/MS), including enolase-1, phosphoglycerate mutase-1, actinin, 14-3-3 protein epsilon, alpha-tubulin 2, and ubiquitin-activating enzyme E1. The increased enolase-1 level was confirmed by Western blot analysis. Functional analysis revealed that enolase-1 dramatically induced COM crystal invasion through ECM migrating chamber in a dose-dependent manner. Moreover, enolase-1 bound onto U937 monocytic cell surface markedly enhanced cell migration through the ECM migrating chamber. In summary, our data indicated that the increased secretory enolase-1 induced by COM crystals played an important role in crystal invasion and inflammatory process in renal interstitium. PMID:27045290

  15. Loss of Cystic Fibrosis Transmembrane Regulator Impairs Intestinal Oxalate Secretion.

    PubMed

    Knauf, Felix; Thomson, Robert B; Heneghan, John F; Jiang, Zhirong; Adebamiro, Adedotun; Thomson, Claire L; Barone, Christina; Asplin, John R; Egan, Marie E; Alper, Seth L; Aronson, Peter S

    2017-01-01

    Patients with cystic fibrosis have an increased incidence of hyperoxaluria and calcium oxalate nephrolithiasis. Net intestinal absorption of dietary oxalate results from passive paracellular oxalate absorption as modified by oxalate back secretion mediated by the SLC26A6 oxalate transporter. We used mice deficient in the cystic fibrosis transmembrane conductance regulator gene (Cftr) to test the hypothesis that SLC26A6-mediated oxalate secretion is defective in cystic fibrosis. We mounted isolated intestinal tissue from C57BL/6 (wild-type) and Cftr(-/-) mice in Ussing chambers and measured transcellular secretion of [(14)C]oxalate. Intestinal tissue isolated from Cftr(-/-) mice exhibited significantly less transcellular oxalate secretion than intestinal tissue of wild-type mice. However, glucose absorption, another representative intestinal transport process, did not differ in Cftr(-/-) tissue. Compared with wild-type mice, Cftr(-/-) mice showed reduced expression of SLC26A6 in duodenum by immunofluorescence and Western blot analysis. Furthermore, coexpression of CFTR stimulated SLC26A6-mediated Cl(-)-oxalate exchange in Xenopus oocytes. In association with the profound defect in intestinal oxalate secretion, Cftr(-/-) mice had serum and urine oxalate levels 2.5-fold greater than those of wild-type mice. We conclude that defective intestinal oxalate secretion mediated by SLC26A6 may contribute to the hyperoxaluria observed in this mouse model of cystic fibrosis. Future studies are needed to address whether similar mechanisms contribute to the increased risk for calcium oxalate stone formation observed in patients with cystic fibrosis.

  16. CT visible internal stone structure, but not Hounsfield unit value, of calcium oxalate monohydrate (COM) calculi predicts lithotripsy fragility in vitro.

    PubMed

    Zarse, Chad A; Hameed, Tariq A; Jackson, Molly E; Pishchalnikov, Yuri A; Lingeman, James E; McAteer, James A; Williams, James C

    2007-08-01

    Calcium oxalate monohydrate (COM) stones are often resistant to breakage using shock wave (SW) lithotripsy. It would be useful to identify by computed tomography (CT) those COM stones that are susceptible to SW's. For this study, 47 COM stones (4-10 mm in diameter) were scanned with micro CT to verify composition and also for assessment of heterogeneity (presence of pronounced lobulation, voids, or apatite inclusions) by blinded observers. Stones were then placed in water and scanned using 64-channel helical CT. As with micro CT, heterogeneity was assessed by blinded observers, using high-bone viewing windows. Then stones were broken in a lithotripter (Dornier Doli-50) over 2 mm mesh, and SW's counted. Results showed that classification of stones using micro CT was highly repeatable among observers (kappa = 0.81), and also predictive of stone fragility. Stones graded as homogeneous required 1,874 +/- 821 SW/g for comminution, while stones with visible structure required half as many SW/g, 912 +/- 678. Similarly, when stones were graded by appearance on helical CT, classification was repeatable (kappa = 0.40), and homogeneous stones required more SW's for comminution than did heterogeneous stones (1,702 +/- 993 SW/g, compared to 907 +/- 773). Stone fragility normalized to stone size did not correlate with Hounsfield units (P = 0.85). In conclusion, COM stones of homogeneous structure require almost twice as many SW's to comminute than stones of similar mineral composition that exhibit internal structural features that are visible by CT. This suggests that stone fragility in patients could be predicted using pre-treatment CT imaging. The findings also show that Hounsfield unit values of COM stones did not correlate with stone fragility. Thus, it is stone morphology, rather than X-ray attenuation, which correlates with fragility to SW's in this common stone type.

  17. Calcium oxalate crystals induces tight junction disruption in distal renal tubular epithelial cells by activating ROS/Akt/p38 MAPK signaling pathway.

    PubMed

    Yu, Lei; Gan, Xiuguo; Liu, Xukun; An, Ruihua

    2017-11-01

    Tight junction plays important roles in regulating paracellular transports and maintaining cell polarity. Calcium oxalate monohydrate (COM) crystals, the major crystalline composition of kidney stones, have been demonstrated to be able to cause tight junction disruption to accelerate renal cell injury. However, the cellular signaling involved in COM crystal-induced tight junction disruption remains largely to be investigated. In the present study, we proved that COM crystals induced tight junction disruption by activating ROS/Akt/p38 MAPK pathway. Treating Madin-Darby canine kidney (MDCK) cells with COM crystals induced a substantial increasing of ROS generation and activation of Akt that triggered subsequential activation of ASK1 and p38 mitogen-activated protein kinase (MAPK). Western blot revealed a significantly decreased expression of ZO-1 and occludin, two important structural proteins of tight junction. Besides, redistribution and dissociation of ZO-1 were observed by COM crystals treatment. Inhibition of ROS by N-acetyl-l-cysteine (NAC) attenuated the activation of Akt, ASK1, p38 MAPK, and down-regulation of ZO-1 and occludin. The redistribution and dissociation of ZO-1 were also alleviated by NAC treatment. These results indicated that ROS were involved in the regulation of tight junction disruption induced by COM crystals. In addition, the down-regulation of ZO-1 and occludin, the phosphorylation of ASK1 and p38 MAPK were also attenuated by MK-2206, an inhibitor of Akt kinase, implying Akt was involved in the disruption of tight junction upstream of p38 MAPK. Thus, these results suggested that ROS-Akt-p38 MAPK signaling pathway was activated in COM crystal-induced disruption of tight junction in MDCK cells.

  18. Modulation of calcium oxalate dihydrate growth by selective crystal-face binding of phosphorylated osteopontin and polyaspartate peptide showing occlusion by sectoral (compositional) zoning.

    PubMed

    Chien, Yung-Ching; Masica, David L; Gray, Jeffrey J; Nguyen, Sarah; Vali, Hojatollah; McKee, Marc D

    2009-08-28

    Calcium oxalate dihydrate (COD) mineral and the urinary protein osteopontin/uropontin (OPN) are commonly found in kidney stones. To investigate the effects of OPN on COD growth, COD crystals were grown with phosphorylated OPN or a polyaspartic acid-rich peptide of OPN (DDLDDDDD, poly-Asp(86-93)). Crystals grown with OPN showed increased dimensions of the {110} prismatic faces attributable to selective inhibition at this crystallographic face. At high concentrations of OPN, elongated crystals with dominant {110} faces were produced, often with intergrown, interpenetrating twin crystals. Poly-Asp(86-93) dose-dependently elongated crystal morphology along the {110} faces in a manner similar to OPN. In crystal growth studies using fluorescently tagged poly-Asp(86-93) followed by imaging of crystal interiors using confocal microscopy, sectoral (compositional) zoning in COD was observed resulting from selective binding and incorporation (occlusion) of peptide exclusively into {110} crystal sectors. Computational modeling of poly-Asp(86-93) adsorption to COD {110} and {101} surfaces also suggests increased stabilization of the COD {110} surface and negligible change to the natively stable {101} surface. Ultrastructural, colloidal-gold immunolocalization of OPN by transmission electron microscopy in human stones confirmed an intracrystalline distribution of OPN. In summary, OPN and its poly-Asp(86-93) sequence similarly affect COD mineral growth; the {110} crystallographic faces become enhanced and dominant attributable to {110} face inhibition by the protein/peptide, and peptides can incorporate into the mineral phase. We, thus, conclude that the poly-Asp(86-93) domain is central to the OPN ability to interact with the {110} faces of COD, where it binds to inhibit crystal growth with subsequent intracrystalline incorporation (occlusion).

  19. Speciation in experimental C-O-H fluids produced by the thermal dissociation of oxalic acid dihydrate

    USGS Publications Warehouse

    Morgan, G.B.; Chou, I.-Ming; Pasteris, J.D.

    1992-01-01

    Fluid speciations and their related reaction pathways were studied in C-O-H-system fluids produced by the thermal dissociation of oxalic acid dihydrate (OAD: H2C2O4 ?? 2H2O) sealed in silica glass capsules. Experiments were conducted in the temperature range 230-750??C, with bulk fluid densities in the range 0.01-0.53 g/cm3. Pressure was controlled by temperature and density in the isochoric systems. The quenched products of dissociation experiments were an aqueous liquid and one (supercritical fluid) or, rarely, two (vapor plus liquid) carbonic phase (s). In-situ Raman microanalyses were performed on the quenched carbonic phases at room temperature, at which fluid pressures ranged from about 50 to 340 bars. Bulk fluid speciations were reconstructed from the Raman analyses via mass balance constraints, and appear to monitor the true fluid speciations at run conditions. In experiments from the lowtemperature range (230-350??C), fluid speciations record the dissociation of OAD according to the reaction OAD = CO2 + CO + 3H2O. A process of the form CO + H2O = CO2 + H2 is driven to the right with increasing temperature. The hydrogen gas produced tends to escape from the sample systems via diffusion into/through the silica glass capsules, shifting bulk compositions toward equimolar binary H2O-CO2 mixtures. The speciations of fluids in experiments with minimal hydrogen loss show poor agreement with speciations calculated for equilibrium fluids by the corresponding-states model of Saxena and Fei (1988). Such disagreement suggests that the formations of CH4 and graphite are metastably inhibited in the current experiments, which correlates with their absence or trivial abundances in experimental products. Moreover, calculations in which the stabilities of methane and graphite are suppressed suggest that such metastable equilibrium is approached only in experiments at temperatures greater than about 600-650??C. These results have applications to fluid processes in geological

  20. Evaluation of Oxalate Concentration in the U.S. Spinach Germplasm Collection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    In addition to its high nutrient content, spinach (Spinacia oleracea L.) is also known to have greater amount of oxalic acid than most crops. Oxalic acid may form crystals with minerals to reduce the bioavailability and absorption of calcium and iron in diets, and calcium oxalate may deposit in the...

  1. Oxalate Content of Taro Leaves Grown in Central Vietnam.

    PubMed

    Du Thanh, Hang; Phan Vu, Hai; Vu Van, Hai; Le Duc, Ngoan; Le Minh, Tuan; Savage, Geoffrey

    2017-01-01

    Leaves were harvested from four different cultivars of Colocasia esculenta and three cultivars of Alocasia odora that were growing on nine different farms in central Vietnam. The total, soluble and insoluble oxalate contents of the leaves were extracted and measured using HPLC chromatography. Total calcium determinations were also carried out on the same samples. The total oxalate content of the leaves ranged from 433.8 to 856.1 mg/100 g wet matter (WM) while the soluble oxalate ranged from 147.8 to 339.7 mg/100 g WM. The proportion of soluble oxalate ranged from 28% to 41% (overall mean 35%) of the total oxalate content of the leaves. The equivalent insoluble oxalate proportion ranged from 59% to 72% of the total (overall mean 65%). There was little difference between the Colocasia esculenta and Alocasia odora taro cultivars, although the total oxalate content was significantly higher in Alocasia odora cultivars. The overall mean total calcium content was 279.5 mg/100 WM and the percentage of insoluble calcium bound as calcium oxalate ranged from 31.7% to 57.3% of the total calcium content (overall mean 47.1%). The oxalate content in taro leaves is a major factor to consider when different cultivars of taro are recommended for human or animal consumption.

  2. Oxalate Content of Taro Leaves Grown in Central Vietnam

    PubMed Central

    Du Thanh, Hang; Phan Vu, Hai; Vu Van, Hai; Le Duc, Ngoan; Le Minh, Tuan; Savage, Geoffrey

    2017-01-01

    Leaves were harvested from four different cultivars of Colocasia esculenta and three cultivars of Alocasia odora that were growing on nine different farms in central Vietnam. The total, soluble and insoluble oxalate contents of the leaves were extracted and measured using HPLC chromatography. Total calcium determinations were also carried out on the same samples. The total oxalate content of the leaves ranged from 433.8 to 856.1 mg/100 g wet matter (WM) while the soluble oxalate ranged from 147.8 to 339.7 mg/100 g WM. The proportion of soluble oxalate ranged from 28% to 41% (overall mean 35%) of the total oxalate content of the leaves. The equivalent insoluble oxalate proportion ranged from 59% to 72% of the total (overall mean 65%). There was little difference between the Colocasia esculenta and Alocasia odora taro cultivars, although the total oxalate content was significantly higher in Alocasia odora cultivars. The overall mean total calcium content was 279.5 mg/100 WM and the percentage of insoluble calcium bound as calcium oxalate ranged from 31.7% to 57.3% of the total calcium content (overall mean 47.1%). The oxalate content in taro leaves is a major factor to consider when different cultivars of taro are recommended for human or animal consumption. PMID:28231080

  3. Enzymatic hydrolysis of phytate and effects on soluble oxalate concentration in foods.

    PubMed

    Israr, Beenish; Frazier, Richard A; Gordon, Michael H

    2017-01-01

    Soluble oxalate in foods is major concern for kidney stone formers due to its tendency to increase urinary oxalate concentration. Phytate forms complexes with cations, which increases soluble oxalate by making cations unavailable to precipitate oxalate. Thus, in order to reduce soluble oxalate, bran samples (wheat, oat and barley) and bean samples (red kidney bean and white bean) were treated with phytase. Release of phosphate after phytate degradation and its association with calcium was determined. Phosphate concentration increased after application of phytase in all samples, but effect on soluble oxalate concentration varied. Wheat and oat bran showed significant reduction (P<0.05) in soluble oxalate compared to bean samples. Wheat bran, oat bran and white bean had a lower calcium:phosphate ratio than barley bran and red kidney beans. Correlation of the calcium:phosphate molar ratio with release of phosphate depends on concentration of calcium ions and this influences soluble oxalate concentration.

  4. Bioavailability of oxalic acid from spinach, sugar beet fibre and a solution of sodium oxalate consumed by female volunteers.

    PubMed

    Hanson, C F; Frankos, V H; Thompson, W O

    1989-03-01

    Oxalate bioavailability from sugar beet fibre (40 g), spinach (25 g) and a solution of sodium oxalate (182 mg) was tested in nine women using a triplicated 3 x 3 Latin square arrangement. Each test substance provided 120 mg oxalic acid. Throughout the study the volunteers consumed a control diet and the test substances were administered at breakfast on specified days. After an initial 2-day control period, oxalate was administered in three test periods that consisted of one test day followed by one control day. Urine collected during 24-hr periods was analysed daily for oxalate. Oxalate excretion did not differ among the five control days and was not increased significantly following the ingestion of sugar beet fibre by the volunteers. Oxalate excretion was greater (P less than 0.0001) for the mean of the spinach and sodium oxalate solution diets than for the mean of the sugar beet fibre and control diets. Oxalate bioavailability from sugar beet fibre was 0.7% compared with bioavailabilities of 4.5 and 6.2% for spinach and oxalate solutions, respectively. The low bioavailability of oxalate from sugar beet fibre may be attributable to its high ratio of minerals (calcium and magnesium) to oxalate, its complex fibre matrix or the loss of the soluble oxalate during processing of sugar beets.

  5. Oxalate urinary calculi in beef steers.

    PubMed

    Huntington, G B; Emerick, R J

    1984-01-01

    Hereford X Angus steers (10/treatment) were fed 90% concentrate diets containing 0.3%, 0.6%, 0.9%, or 1.2% of calcium for 92 days (trial 1) or 114 days (trial 2). Ground limestone was the supplemental calcium source. At slaughter, 12 of 20 steers fed 0.3% calcium had calculi in the urinary bladder or kidneys, compared with 5 of 20 fed 0.6% calcium, 5 of 20 fed 0.9% calcium, and 4 of 20 fed 1.2% calcium. Analyses of calculi indicated they were oxalate calculi. During the first 49 days of trial 2, plasma hydroxyproline concentrations were higher (P less than 0.10) for steers fed 0.3% calcium than for steers fed higher calcium concentrations. Increased bone resorption in steers fed concentrations of 0.3% calcium, resulting in increased plasma hydroxyproline, an oxalate precursor, was indicated as a source of oxalate in calculi and as an explanation of lower occurrence of calculi in steers fed higher concentrations of calcium.

  6. Metabolism of Fructose to Oxalate and Glycolate

    PubMed Central

    Knight, J.; Assimos, D. G.; Easter, L.; Holmes, R. P.

    2011-01-01

    Much attention has been recently directed at fructose consumption because of its association with obesity and subsequent development of chronic diseases. It was recently reported that an increased fructose intake increases the risk of forming kidney stones. It was postulated that fructose consumption may increase urinary oxalate, a risk factor for calcium oxalate kidney stone disease. However, conflicting results have been obtained in human studies examining the relationship between fructose metabolism and oxalate synthesis. To test whether fructose intake influences urinary excretions impacting kidney stone risk, healthy subjects consumed diets controlled in their contents of fructose, oxalate, calcium, and other nutrients. Subjects consumed diets containing 4, 13, and 21% of calories as fructose in a randomized order. No changes in the excretions of oxalate, calcium, and uric acid were observed. In vitro investigations with cultured liver cells incubated with 13C-labeled sugars indicated that neither fructose nor glucose was converted to oxalate by these cells. Fructose metabolism accounted for 12.4 ± 1.6% of the glycolate detected in the culture medium and glucose 6.4 ± 0.9%. Our results suggest that mechanisms for stone risk associated with fructose intake may lie in factors other than those affecting the major stone risk parameters in urine. PMID:20842614

  7. The function of oxalic acid in the human metabolism.

    PubMed

    Robertson, Daniel Stewart

    2011-09-01

    Biochemical reactions in cells which involve oxalic acid are described. It is shown that this compound is required for the formation of uracil and orotic acid. The former is a component of RNA which is common to all cells in the human metabolism. On the basis of the biochemical reactions described a possible treatment to relieve the effects of calcium oxalate renal calculi whose origin is related to the metabolic concentration of oxalic acid is proposed.

  8. Potential role of fluctuations in the composition of renal tubular fluid through the nephron in the initiation of Randall's plugs and calcium oxalate crystalluria in a computer model of renal function.

    PubMed

    Robertson, W G

    2015-01-01

    This article describes an updated computer model which attempts to simulate known renal reabsorption and secretion activity through the nephron (NEPHROSIM) and its possible relevance to the initiation of calcium-containing renal stones. The model shows that, under certain conditions of plasma composition, de novo nucleation of both calcium oxalate (CaOx) and calcium phosphate (CaP) can take place at the end of the descending limb of the Loop of Henle (DLH), particularly in untreated, recurrent idiopathic CaOx stone-formers (RSF). The model incorporates a number of hydrodynamic factors that may influence the subsequent growth of crystals nucleated at the end of the DLH as they progress down the renal tubules. These include the fact that (a) crystals of either CaOx or CaP nucleated at the end of the DLH and travelling close to the walls of the tubule travel at slower velocities than the fluid flowing at the central axis of the tubule, (b) the transit of CaOx crystals travelling close to the tubule walls may be delayed for up to at least 25 min, during which time the crystals may continue to grow if the relative supersaturation with respect to CaOx (RSS CaOx) is high enough and (c) such CaOx crystals may stop moving or even fall back in upward-draining collecting ducts (CD) owing to the Stokes gravitational effect. The model predicts, firstly, that for small, transient increases in plasma oxalate concentration, crystallisation only takes place in the CD and leads to the formation of small crystals which are comfortably passed in the urine and, secondly, that for slightly greater increases in the filtered load of oxalate, spontaneous and/or heterogeneous nucleation of CaOx may occur both at the end of the DLH and in the CD. This latter situation leads to the passage in the final urine of a mixture of large crystals of CaOx (arising from nucleation at the end of the DLH) and small crystals of CaOx (as a result of nucleation originating in the CD). As a result of the

  9. Oxalate catabolism in Arabidopsis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxalic acid is found in most plant species and can serve beneficial roles that protect the plant from a variety of environmental stresses. Excessive amounts of oxalate, however, can be detrimental to plant health. Thus, careful coordination of oxalate metabolism is needed. Despite the important impa...

  10. Oxalic acid has an additional, detoxifying function in Sclerotinia sclerotiorum pathogenesis.

    PubMed

    Heller, Annerose; Witt-Geiges, Tanja

    2013-01-01

    The mechanism of the diseases caused by the necrotroph plant pathogen Sclerotinia sclerotiorum is not well understood. To investigate the role of oxalic acid during infection high resolution, light-, scanning-, transmission electron microscopy and various histochemical staining methods were used. Our inoculation method allowed us to follow degradation of host plant tissue around single hyphae and to observe the reaction of host cells in direct contact with single invading hyphae. After penetration the outer epidermal cell wall matrix appeared degraded around subcuticular hyphae (12-24 hpi). Calcium oxalate crystals were detected in advanced (36-48 hpi) and late (72 hpi) infection stages, but not in early stages. In early infection stages, surprisingly, no toxic effect of oxalic acid eventually secreted by S. sclerotiorum was observed. As oxalic acid is a common metabolite in plants, we propose that attacked host cells are able to metabolize oxalic acid in the early infection stage and translocate it to their vacuoles where it is stored as calcium oxalate. The effects, observed on healthy tissue upon external application of oxalic acid to non-infected, living tissue and cell wall degradation of dead host cells starting at the inner side of the walls support this idea. The results indicate that oxalic acid concentrations in the early stage of infection stay below the toxic level. In plant and fungi oxalic acid/calcium oxalate plays an important role in calcium regulation. Oxalic acid likely could quench calcium ions released during cell wall breakdown to protect growing hyphae from toxic calcium concentrations in the infection area. As calcium antimonate-precipitates were found in vesicles of young hyphae, we propose that calcium is translocated to the older parts of hyphae and detoxified by building non-toxic, stable oxalate crystals. We propose an infection model where oxalic acid plays a detoxifying role in late infection stages.

  11. Growth Conditions To Reduce Oxalic Acid Content of Spinach

    NASA Technical Reports Server (NTRS)

    Johnson-Rutzke, Corinne

    2003-01-01

    A controlled-environment agricultural (CEA) technique to increase the nutritive value of spinach has been developed. This technique makes it possible to reduce the concentration of oxalic acid in spinach leaves. It is desirable to reduce the oxalic acid content because oxalic acid acts as an anti-nutritive calcium-binding component. More than 30 years ago, an enzyme (an oxidase) that breaks down oxalic acid into CO2 and H2O2 was discovered and found to be naturally present in spinach leaves. However, nitrate, which can also be present because of the use of common nitratebased fertilizers, inactivates the enzyme. In the CEA technique, one cuts off the supply of nitrate and keeps the spinach plants cool while providing sufficient oxygen. This technique provides the precise environment that enables the enzyme to naturally break down oxalate. The result of application of this technique is that the oxalate content is reduced by 2/3 in one week.

  12. Calcium

    MedlinePlus

    ... You'll also find calcium in broccoli and dark green, leafy vegetables (especially collard and turnip greens, ... can enjoy good sources of calcium such as dark green, leafy vegetables, broccoli, chickpeas, and calcium-fortified ...

  13. Contrasting calcium localization and speciation in leaves of Medicago trunculata mutant COD5 analyzed via synchrotron X-ray techniques

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxalate-producing plants accumulate calcium oxalate crystals (CaOx(C)) in the range of 3-80%(w/w) of their dry weight, reducing calcium (Ca) bioavailability. The calcium oxalate deficient 5 (cod5) mutant of Medicago truncatula has been previously shown to contain similar Ca, but lower oxalate and Ca...

  14. Effects of vitamin E ingestion on plasma and urinary risk factors for calcium oxalate urolithiasis in two population groups having different stone-risk profiles: evidence of different physiological handling mechanisms.

    PubMed

    Theka, Takalani; Rodgers, Allen; Lewandowski, Sonja; Webber, Dawn; Allie-Hamdulay, Shameez

    2012-04-01

    It has been demonstrated that vitamin E supplementation reduces calciuria and oxaluria and that it may also prevent oxalate-mediated peroxidative injury, all of which reduce the risk of calcium oxalate urolithiasis. In view of the significant difference in stone occurrence in black (B) and white (W) South Africans, we undertook to investigate the effects of vitamin E supplementation in subjects from these two groups. Five healthy males from each group ingested one capsule (400 IU) of vitamin E daily for 60 days. Blood and 24 h urine samples were collected at baseline and on day 60; 24 h dietary questionnaires were simultaneously completed. Urine composition was determined by routine analyses. Urinary and plasma TBARS were determined using a commercially available assay kit while plasma vitamin E was determined by reverse phase HPLC. Plasma vitamin E increased significantly in W but not in B. Urinary and plasma TBARS did not increase in either group. Urinary citrate increased significantly in both groups but the percentage increase in W (169%) was greater than that in B (82%). No other urinary parameter changed significantly. The increase in plasma vitamin E in W but not in B suggests either that the mechanism by which it is packaged into chylomicrons, which are secreted into the systemic circulation, is suppressed in the latter group or that it is differentially absorbed in the two groups. Similarly, to explain the greater increase in citraturia in W compared to B, we speculate that inhibition of lipogenesis of arachidonic acid by vitamin E, ultimately leading to an increase in citraturia, occurs to a lesser extent in B than in W.

  15. Oxalate nephropathy due to 'juicing': case report and review.

    PubMed

    Getting, Jane E; Gregoire, James R; Phul, Ashley; Kasten, Mary J

    2013-09-01

    A patient presented with oxalate-induced acute renal failure that was attributable to consumption of oxalate-rich fruit and vegetable juices obtained from juicing. We describe the case and also review the clinical presentation of 65 patients seen at Mayo Clinic (Rochester, MN) from 1985 through 2010 with renal failure and biopsy-proven renal calcium oxalate crystals. The cause of renal oxalosis was identified for all patients: a single cause for 36 patients and at least 2 causes for 29 patients. Three patients, including our index patient, had presumed diet-induced oxalate nephropathy in the context of chronic kidney disease. Identification of calcium oxalate crystals in a kidney biopsy should prompt an evaluation for causes of renal oxalosis, including a detailed dietary history. Clinicians should be aware that an oxalate-rich diet may potentially precipitate acute renal failure in patients with chronic kidney disease. Juicing followed by heavy consumption of oxalate-rich juices appears to be a potential cause of oxalate nephropathy and acute renal failure.

  16. [Analysis of oxalic acid and oxalates].

    PubMed

    Leskovar, P

    1979-08-01

    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.

  17. Oxalic acid in saliva, teeth and tooth tartar.

    PubMed

    Wahl, R; Kallee, E

    1994-11-01

    Oxalic acid was determined in human saliva, teeth, tartar, and in animal teeth. Saliva from dentally healthy male subjects contained 0.10 +/- 0.09 mmol/l (n = 41) and those of dentally healthy female subjects 0.18 +/- 0.17 mmol/l (n = 40). Oxalic acid in tartar from 16 patients was 3.3 +/- 1.2 mmol/kg tartar. In human teeth, oxalic acid was 1.0 +/- 0.3 mmol/kg in milk teeth (n = 12) and 0.9 +/- 0.6 mmol/kg in permanent teeth (n = 60). Human teeth were sorted into age groups and into molars, incisors and premolars. In animal teeth, oxalic acid content varied widely. The formed calcium oxalate is proposed to be a 'physiological' protective mechanism for teeth.

  18. [Oxalate: a poorly soluble organic waste with consequences].

    PubMed

    Lu, Yimin; Bonny, Olivier

    2015-03-25

    Oxalate is a highly insoluble metabolic waste excreted by the kidneys. Disturbances of oxalate metabolism are encountered in enteric hyperoxaluria (secondary to malabsorption, gastric bypass or in case of insufficient Oxalobacter colonization), in hereditary hyperoxaluria and in intoxication (ethylene glycol, vitamin C). Hyperoxaluria causes a large spectrum of diseases, from isolated hyperoxaluria to kidney stones and nephrocalcinosis formation, eventually leading to kidney failure and systemic oxalosis with life-threatening deposits in vital organs. New causes of hyperoxaluria are arising recently, in particular after gastric bypass surgery, which requires regular and preemptive monitoring. The treatment of hyperoxaluria involves reduction in oxalate intake and increase in calcium intake. Optimal urine dilution and supplementation with inhibitors of kidney stone formation (citrate) are required. Some conditions may need vitamin B6 supplementation, and the addition of probiotics might be useful in the future. Primary care physicians should identify cases of recurrent calcium oxalate stones and severe hyperoxaluria. Further management of hyperoxaluria requires specialized care.

  19. Acute oxalate nephropathy due to 'Averrhoa bilimbi' fruit juice ingestion.

    PubMed

    Bakul, G; Unni, V N; Seethaleksmy, N V; Mathew, A; Rajesh, R; Kurien, G; Rajesh, J; Jayaraj, P M; Kishore, D S; Jose, P P

    2013-07-01

    Irumban puli (Averrhoa bilimbi) is commonly used as a traditional remedy in the state of Kerala. Freshly made concentrated juice has a very high oxalic acid content and consumption carries a high risk of developing acute renal failure (ARF) by deposition of calcium oxalate crystals in renal tubules. Acute oxalate nephropathy (AON) due to secondary oxalosis after consumption of Irumban puli juice is uncommon. AON due to A. bilimbi has not been reported before. We present a series of ten patients from five hospitals in the State of Kerala who developed ARF after intake of I. puli fruit juice. Seven patients needed hemodialysis whereas the other three improved with conservative management.

  20. Electrochemical synthesis and characterization of zinc oxalate nanoparticles

    SciTech Connect

    Shamsipur, Mojtaba; Roushani, Mahmoud; Pourmortazavi, Seied Mahdi

    2013-03-15

    Highlights: ► Synthesis of zinc oxalate nanoparticles via electrolysis of a zinc plate anode in sodium oxalate solutions. ► Design of a Taguchi orthogonal array to identify the optimal experimental conditions. ► Controlling the size and shape of particles via applied voltage and oxalate concentration. ► Characterization of zinc oxalate nanoparticles by SEM, UV–vis, FT-IR and TG–DTA. - Abstract: A rapid, clean and simple electrodeposition method was designed for the synthesis of zinc oxalate nanoparticles. Zinc oxalate nanoparticles in different size and shapes were electrodeposited by electrolysis of a zinc plate anode in sodium oxalate aqueous solutions. It was found that the size and shape of the product could be tuned by electrolysis voltage, oxalate ion concentration, and stirring rate of electrolyte solution. A Taguchi orthogonal array design was designed to identify the optimal experimental conditions. The morphological characterization of the product was carried out by scanning electron microscopy. UV–vis and FT-IR spectroscopies were also used to characterize the electrodeposited nanoparticles. The TG–DTA studies of the nanoparticles indicated that the main thermal degradation occurs in two steps over a temperature range of 350–430 °C. In contrast to the existing methods, the present study describes a process which can be easily scaled up for the production of nano-sized zinc oxalate powder.

  1. Reduction of Oxalate Levels in Tomato Fruit and Consequent Metabolic Remodeling Following Overexpression of a Fungal Oxalate Decarboxylase1[W

    PubMed Central

    Chakraborty, Niranjan; Ghosh, Rajgourab; Ghosh, Sudip; Narula, Kanika; Tayal, Rajul; Datta, Asis; Chakraborty, Subhra

    2013-01-01

    The plant metabolite oxalic acid is increasingly recognized as a food toxin with negative effects on human nutrition. Decarboxylative degradation of oxalic acid is catalyzed, in a substrate-specific reaction, by oxalate decarboxylase (OXDC), forming formic acid and carbon dioxide. Attempts to date to reduce oxalic acid levels and to understand the biological significance of OXDC in crop plants have met with little success. To investigate the role of OXDC and the metabolic consequences of oxalate down-regulation in a heterotrophic, oxalic acid-accumulating fruit, we generated transgenic tomato (Solanum lycopersicum) plants expressing an OXDC (FvOXDC) from the fungus Flammulina velutipes specifically in the fruit. These E8.2-OXDC fruit showed up to a 90% reduction in oxalate content, which correlated with concomitant increases in calcium, iron, and citrate. Expression of OXDC affected neither carbon dioxide assimilation rates nor resulted in any detectable morphological differences in the transgenic plants. Comparative proteomic analysis suggested that metabolic remodeling was associated with the decrease in oxalate content in transgenic fruit. Examination of the E8.2-OXDC fruit proteome revealed that OXDC-responsive proteins involved in metabolism and stress responses represented the most substantially up- and down-regulated categories, respectively, in the transgenic fruit, compared with those of wild-type plants. Collectively, our study provides insights into OXDC-regulated metabolic networks and may provide a widely applicable strategy for enhancing crop nutritional value. PMID:23482874

  2. The effect of preincubation of seed crystals of uric acid and monosodium urate with undiluted human urine to induce precipitation of calcium oxalate in vitro : implications for urinary stone formation.

    PubMed Central

    Grover, Phulwinder K.; Ryall, Rosemary L.

    2002-01-01

    BACKGROUND: Previous studies demonstrated that crystals of uric acid (UA) and sodium urate (NaU) can induce the precipitation of calcium oxalate (CaOx) from its inorganic metastable solutions, but similar effects have not been unequivocally shown to occur in urine. The aim of this investigation was to determine whether preincubation of these seeds with urine alter their ability to induce deposition of CaOx from solution and thus provide a possible explanation for discrepancy of results obtained from aqueous inorganic solutions and undiluted urine. MATERIALS AND METHODS: The effects of commercial seed crystals of UA, NaU and CaOx (6 mg/100 ml) on CaOx crystallization were compared in a solution with the same crystals that had been preincubated for 3 hours with healthy male urine. A Coulter Counter was used to follow the crystallization and decrease in soluble (14) C-oxalate was measured to determine the deposition of CaOx. The precipitated particles were examined by scanning electron microscopy (SEM). The preincubated seeds were demineralized and proteins released were analyzed by sodium dodecylsulphate polyacrylamide gel electrophoresis (SDS-PAGE). RESULTS: Analysis of (14) C-oxalate data revealed that while treated UA seeds did not affect CaOx deposition, those of NaU and CaOx inhibited the process by 51.9 (p<0.05) and 8.5% (p<0.05) relative to their respective untreated counterparts. Particle size analysis showed that the average modal sizes of particles precipitated in the presence of treated seed crystals of UA, NaU, and CaOx were very similar to those deposited in the presence of their respective untreated controls. These findings were confirmed by SEM which also showed that seed crystals of UA and NaU, untreated and treated, were attached like barnacles upon the surfaces of CaOx crystals which themselves were bigger than those precipitated in the presence of CaOx seeds. SDS-PAGE analysis of the demineralized treated seeds showed that they all selectively

  3. Acute oxalate nephropathy associated with orlistat

    PubMed Central

    Humayun, Youshay; Ball, Kenneth C.; Lewin, Jack R.; Lerant, Anna A.; Fülöp, Tibor

    2016-01-01

    Background: Obesity is a major world-wide epidemic which has led to a surge of various weight loss-inducing medical or surgical treatments. Orlistat is a gastrointestinal lipase inhibitor used as an adjunct treatment of obesity and type 2 diabetes mellitus to induce clinically significant weight loss via fat malabsorption. Case Presentation: We describe a case of a 76-year-old female with past medical history of chronic kidney disease (baseline serum creatinine was 1.5-2.5 mg/dL), hypertension, gout and psoriatic arthritis, who was admitted for evaluation of elevated creatinine, peaking at 5.40 mg/dL. She was started on orlistat 120 mg three times a day six weeks earlier. Initial serologic work-up remained unremarkable. Percutaneous kidney biopsy revealed massive calcium oxalate crystal depositions with acute tubular necrosis and interstitial inflammation. Serum oxalate level returned elevated at 45 mm/l (normal <27). Timed 24-hour urine collection documented increased oxalate excretion repeatedly (54-96 mg/24 hour). After five renal dialysis sessions in eighth days she gradually regained her former baseline kidney function with creatinine around 2 mg/dL. Given coexisting proton-pump inhibitor therapy, only per os calcium-citrate provided effective intestinal oxalate chelation to control hyperoxaluria. Conclusions: Our case underscores the potential of medically induced fat malabsorption to lead to an excessive oxalate absorption and acute kidney injury (AKI), especially in subjects with pre-existing renal impairment. Further, it emphasizes the importance of kidney biopsy to facilitate early diagnosis and treatment. PMID:27152294

  4. The effect of soaking and cooking on the oxalate content of taro leaves.

    PubMed

    Savage, G P; Dubois, M

    2006-01-01

    Pacific Island people commonly eat taro (Colocasia esculenta var. Schott) as a staple food in their home islands and also like to consume this familiar food when living in New Zealand. Some of these foods are imported from the islands and some attempts are, currently, being made to grow these crops in New Zealand. The taro leaves in this experiment were grown in a greenhouse in the North Island of New Zealand. The soluble oxalate content of the raw leaves was 236.10 mg oxalate/100 g wet matter (WM). Soaking the raw leaves in water for 30 min marginally reduces the soluble oxalate content by leaching into the tap water. Soaking for 18 h results in a 26% reduction in the soluble oxalate content of the raw leaves. During the soaking treatments the insoluble oxalate (calcium oxalate) content of the leaves remained constant (mean 171.64 mg oxalate/100 g WM). Boiling the taro leaves resulted in a 36% loss of soluble oxalates, while the soluble oxalate content of baked tissue was very similar to the raw tissue. The mean insoluble oxalate content of the raw, boiled and baked tissue was 226.28 mg oxalate/100 g WM. Overall, boiling the taro leaves was an effective way of reducing the soluble oxalate content of the cooked tissue.

  5. Oxalate Synthesis and Pyrolysis: A Colorful Introduction to Stoichiometry

    ERIC Educational Resources Information Center

    Vannatta, Michael W.; Richards-Babb, Michelle; Sweeney, Robert J.

    2010-01-01

    Metal oxalate synthesis and pyrolysis provides an opportunity for students to (i) learn stoichiometry, (ii) experience the consequences of proper stoichiometric calculations and experimental techniques, and (iii) be introduced to the relevance of chemistry by highlighting oxalates in context, for example, usages and health effects. At our…

  6. Calcium

    MedlinePlus

    ... milligrams) of calcium each day. Get it from: Dairy products. Low-fat milk, yogurt, cheese, and cottage ... lactase that helps digest the sugar (lactose) in dairy products, and may have gas, bloating, cramps, or ...

  7. The pathogenic white-rot fungus Heterobasidion parviporum responds to spruce xylem defense by enhanced production of oxalic acid.

    PubMed

    Nagy, Nina Elisabeth; Kvaalen, Harald; Fongen, Monica; Fossdal, Carl Gunnar; Clarke, Nicholas; Solheim, Halvor; Hietala, Ari M

    2012-11-01

    Pathogen challenge of tree sapwood induces the formation of reaction zones with antimicrobial properties such as elevated pH and cation content. Many fungi lower substrate pH by secreting oxalic acid, its conjugate base oxalate being a reductant as well as a chelating agent for cations. To examine the role of oxalic acid in pathogenicity of white-rot fungi, we conducted spatial quantification of oxalate, transcript levels of related fungal genes, and element concentrations in heartwood of Norway spruce challenged naturally by Heterobasidion parviporum. In the pathogen-compromised reaction zone, upregulation of an oxaloacetase gene generating oxalic acid coincided with oxalate and cation accumulation and presence of calcium oxalate crystals. The colonized inner heartwood showed trace amounts of oxalate. Moreover, fungal exposure to the reaction zone under laboratory conditions induced oxaloacetase and oxalate accumulation, whereas heartwood induced a decarboxylase gene involved in degradation of oxalate. The excess level of cations in defense xylem inactivates pathogen-secreted oxalate through precipitation and, presumably, only after cation neutralization can oxalic acid participate in lignocellulose degradation. This necessitates enhanced production of oxalic acid by H. parviporum. This study is the first to determine the true influence of white-rot fungi on oxalate crystal formation in tree xylem.

  8. Oxalate mediated nephronal impairment and its inhibition by c-phycocyanin: a study on urolithic rats.

    PubMed

    Farooq, Shukkur Muhammed; Ebrahim, Abdul Shukkur; Subramhanya, Karthik Harve; Sakthivel, Ramasamy; Rajesh, Nachiappa Ganesh; Varalakshmi, Palaninathan

    2006-03-01

    The assumption of oxidative stress as a mechanism in oxalate induced renal damage suggests that antioxidants might play a beneficial role against oxalate toxicity. An in vivo model was used to investigate the effect of C-phycocyanin (from aquatic micro algae; Spirulina spp.), a known antioxidant, against calcium oxalate urolithiasis. Hyperoxaluria was induced in two of the 4 groups of Wistar albino rats (n = 6 in each) by intraperitoneally injecting sodium oxalate (70 mg/kg body weight). A pretreatment of phycocyanin (100 mg/kg body weight) as a single oral dosage was given, one hour prior to oxalate challenge. An untreated control and drug control (phycocyanin alone) were employed. Phycocyanin administration resulted in a significant improvement (p < 0.001) in the thiol content of renal tissue and RBC lysate via increasing glutathione and reducing malondialdehyde levels in the plasma of oxalate induced rats (p < 0.001), indicating phycocyanin's antioxidant effect on oxalate mediated oxidative stress. Administering phycocyanin after oxalate treatment significantly increased catalase and glucose-6-phosphate dehydrogenase activity (p < 0.001) in RBC lysate suggesting phycocyanin as a free radical quencher. Assessing calcium oxalate crystal retention in renal tissue using polarization microscopy and renal ultrastructure by electron microscopy reveals normal features in phycocyanin-- pretreated groups. Thus the study presents positive pharmacological implications of phycocyanin against oxalate mediated nephronal impairment and warrants further work to tap this potential aquatic resource for its medicinal application.

  9. Uropontin in urinary calcium stone formation.

    PubMed

    Hoyer, J R

    1994-01-01

    Normal urine is frequently supersaturated with respect to calcium oxalate. Thus, urinary inhibitors of crystallization appear to have an important role in preventing urinary stone formation. Uropontin was isolated by monoclonal antibody immunoaffinity chromatography and has the same N-terminal sequence as osteopontin derived from bone. This urinary form of osteopontin is a potent inhibitor of calcium oxalate monohydrate crystal growth at concentrations (approximately 0.1 microM) that normally prevail in human urine. Interaction with calcium oxalate monohydrate in vivo was shown by analysis of EDTA extracts of calcium stones. Uropontin is an abundant component of calcium oxalate monohydrate stones and present in only trace quantities in calcium oxalate dihydrate and hydroxyapatite stones. However, the precise role of uropontin in the pathogenesis of urinary stone formation is not known and is the subject of ongoing investigations.

  10. Thermal degradation of aqueous oxalate species

    SciTech Connect

    Crossey, L.J. )

    1991-06-01

    The aqueous thermal degradation of oxalic acid (a naturally occurring dicarboxylic acid) and its anions has been examined experimentally under variable conditions of temperature (160-230C), time (24-96 h), buffered pH (4-7), and ionic strength (0.2-0.5 M). Decomposition of oxalate species follows a first-order rate law. Degradation rate increases with decreasing pH; the effects of ionic strength are not significant. Changes in reaction rate over the temperature range studied give activation energies that range from 29-50 kcal/mol over a starting solution pH range of 5-7. Extrapolation of these data to sedimentary basin temperatures suggests that oxalate species may be long-lived in formation waters. At 80C, half-lives range from 2,500 to 28,000 years at pH values of 5 and 7, respectively. Formate species are relatively stable degradation products over the range of conditions studied. Comparison of these data are relatively stable degradation products over the range of conditions studied. Comparison of these data with results of other thermal degradation studies of carboxylic acids and their anions indicate that acetate stability {much gt} formate stability > oxalate stability > gallate and malonate stability. These results are consistent with the high concentrations of acetate relative to oxalate and malonate observed in formation waters.

  11. Dissociation of protonated oxalic acid [HOOC-C(OH)2]+ into H3O+ + CO + CO2: An experimental and CBS-QB3 computational study

    NASA Astrophysics Data System (ADS)

    Ervasti, Henri K.; Lee, Richard; Burgers, Peter C.; Ruttink, Paul J. A.; Terlouw, Johan K.

    2006-03-01

    The predominant dissociation process observed for metastable protonated oxalic acid ions HOOC-C(OH)2+ (generated by self-protonation) leads to H3O++ CO + CO2. We have traced the mechanism of this intriguing reaction using the CBS-QB3 model chemistry. Our calculations show that a unique ter-body complex, OCO...H3O+...CO, plays a key role in the rearrangement process. This complex can also dissociate to the proton bound dimers [H2O...H...OCO]+ and [H2O...H...CO]+ which are minor processes observed in the metastable ion mass spectrum. A further minor process leads to the proton bound dimer OCO...H+...CO which is formed by water extrusion from the ter-body complex. Arguments are provided that the ter-body complex is also generated in the ion source by the collision encounter between neutral and ionized oxalic acid.

  12. Bio-inspired Design of Electrocatalysts for Oxalate Oxidation: a Combined Experimental and Computational Study of Mn–N–C Catalysts

    SciTech Connect

    Matanovic, Ivana; Babanova, Sofia; Perry, Albert; Serov, Alexey; Artyushkova, Kateryna; Atanassov, Plamen

    2015-05-28

    We report a novel non-platinum group metal (non-PGM) catalyst derived from Mn and amino- antipyrine (MnAAPyr) that shows electrochemical activity towards the oxidation of oxalic acid comparable to Pt with an onset potential for oxalate oxidation measured to be 0.714 * 0.002 V vs. SHE at pH = 4. The material has been synthesized using a templating Sacrificial Support Method with manganese nitrate and 4-aminoantipyrine as precursors. This catalyst is a nano-structured material in which Mn is atomically dispersed on a nitrogendoped graphene matrix. XPS studies reveal high abundance of pyridinic, Mn–Nx, and pyrrolic nitrogen pointing towards the conclusion that pyridinic nitrogen atoms coordinated to manganese constitute the active centers. Thus, the main features of the MnAAPyr catalyst are it exhibits similarity to the active sites of naturally occurring enzymes that are capable of efficient and selective oxidation of oxalic acid. Density functional theory in plane wave formalism with Perdew, Burke and Ernzerhof functional was further used to study the stability and activity of different one-metal active centers that could exist in the catalyst. The results show that the stability of the Mn–Nx sites changes in the following order: MnN4 4 MnN3C 4 MnN2C2 4 MnN3. Based on the overpotentials of 0.64 V and 0.71 V vs. SHE, calculated using the free energy diagrams for the oxalate oxidation mechanism, we could conclude that the MnN3C and MnN2C2 sites are most probable Mn–Nx sites responsible for the reported catalytic activity of the new catalyst.

  13. Mode of Action: Oxalate Crystal-Induced Renal Tubule Degeneration and Glycolic Acid-Induced Dysmorphogenesis—Renal and Developmental Effects of Ethylene Glycol

    SciTech Connect

    Corley, Rick A.; Meek, M E.; Carney, E W.

    2005-10-01

    Ethylene glycol can cause both renal and developmental toxicity, with metabolism playing a key role in the mode of action (MOA) for each form of toxicity. Renal toxicity is ascribed to the terminal metabolite oxalic acid, which precipitates in the kidney in the form of calcium oxalate crystals and is believed to cause physical damage to the renal tubules. The human relevance of the renal toxicity of ethylene glycol is indicated by the similarity between animals and humans of metabolic pathways, the observation of renal oxalate crystals in toxicity studies in experimental animals and human poisonings, and cases of human kidney and bladder stones related to dietary oxalates and oxalate precursors. High-dose gavage exposures to ethylene glycol also cause axial skeletal defects in rodents (but not rabbits), with the intermediary metabolite, glycolic acid, identified as the causative agent. However, the mechanism by which glycolic acid perturbs development has not been investigated sufficiently to develop a plausible hypothesis of mode of action, nor have any cases of ethylene glycol-induced developmental effects been reported in humans. Given this, and the variations in sensitivity between animal species in response, the relevance to humans of ethylene glycol-induced developmental toxicity in animals is unknown at this time.

  14. Experimental study of the replacement of calcite by calcium sulphates

    NASA Astrophysics Data System (ADS)

    Ruiz-Agudo, E.; Putnis, C. V.; Hövelmann, J.; Álvarez-Lloret, P.; Ibáñez-Velasco, A.; Putnis, A.

    2015-05-01

    Among the most relevant mineral replacement reactions are those involving sulphates and carbonates, which have important geological and technological implications. Here it is shown experimentally that during the interaction of calcite (CaCO3) cleavage surfaces with sulphate-bearing acidic solutions, calcite is ultimately replaced by gypsum (CaSO4 2H2O) and anhydrite (CaSO4), depending on the reaction temperature. Observations suggest that this occurs most likely via an interface-coupled dissolution-precipitation reaction, in which the substrate is replaced pseudomorphically by the product. At 120 and 200 °C gypsum and/or bassanite (CaSO4·0.5H2O) form as precursor phases for the thermodynamically stable anhydrite. Salinity promotes the formation of less hydrated precursor phases during the replacement of calcite by anhydrite. The reaction stops before equilibrium with respect to calcite is reached and during the course of the reaction most of the bulk solutions are undersaturated with respect to the precipitating phase(s). A mechanism consisting of the dissolution of small amounts of solid in a thin layer of fluid at the mineral-fluid interface and the subsequent precipitation of the product phase from this layer is in agreement with these observations. PHREEQC simulations performed in the framework of this mechanism highlight the relevance of transport and surface reaction kinetics on the volume change associated with the CaCO3-CaSO4 replacement. Under our experimental conditions, this reaction occurs with a positive volume change, which ultimately results in passivation of the unreacted substrate before calcite attains equilibrium with respect to the bulk solution.

  15. Literature review for oxalate oxidation processes and plutonium oxalate solubility

    SciTech Connect

    Nash, C. A.

    2015-10-01

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign.

  16. Multiorgan crystal deposition following intravenous oxalate infusion in rat

    SciTech Connect

    Blumenfrucht, M.J.; Cheeks, C.; Wedeen, R.P.

    1986-06-01

    Deposition of calcium oxalate is responsible for the pathologic manifestations of oxalosis and may contribute to multiorgan dysfunction in uremia and to the progression of renal damage after renal failure is established. We have developed a rat model of oxalosis using a single intravenous injection of sodium oxalate, 0.3 mmol./kg. body weight, in rats. Polarized light microscopy and section freeze-dry autoradiography were used to identify /sup 14/C-oxalate within the renal parenchyma and in extrarenal organs. /sup 14/C-oxalate crystals under three mu in length were identified within one min. of injection in proximal tubule lumens. Section freeze-dry autoradiography showed occasional minute crystals within glomeruli, heart, lung and liver at one hr. In contrast to concentrative cellular uptake demonstrated in rat renal cortical slices in vitro, intracellular accumulation of /sup 14/C-oxalate could not be detected in vivo. Within the first 24 hr., renal oxalate retention reached a maximum of 25 +/- 4 per cent of the injected dose/gm. kidney compared to a maximum of only 7 +/- 3 per cent/gm. kidney after intraperitoneal administration. Although less than one per cent dose/gm. kidney remained after one week, crystal fragments were scattered throughout the cortex and medulla, often surrounded by foci of interstitial nephritis. The retention of crystals in kidney and other body organs following i.v. oxalate provides a model of oxalosis which stimulates pathophysiologic events in a variety of clinical situations characterized by transiently or persistently elevated serum oxalate.

  17. Gut microbiota and oxalate homeostasis

    PubMed Central

    2017-01-01

    This perspective focuses on how the gut microbiota can impact urinary oxalate excretion in the context of hyperoxaluria, a major risk factor in kidney stone disease. In the genetic disease of Primary Hyperoxaluria Type 1 (PH1), an increased endogenous production of oxalate, due to a deficiency of the liver enzyme alanine-glyoxylate aminotransferase (AGT), results in hyperoxaluria and oxalate kidney stones. The constant elevation in urinary oxalate in PH1 patients ultimately leads to tissue deposition of oxalate, renal failure and death and the only known cure for PH1 is a liver or liver-kidney transplant. The potential impact of a probiotic/therapeutic approach may be clinically significant in PH1 and could also extend to a much larger population of idiopathic oxalate stone formers who comprise ~12% of Americans, individuals with enteric hyperoxaluria, and an emerging population of hyperoxaluric patients who have undergone bariatric surgery and develop kidney stone disease as a consequence. PMID:28217701

  18. Crystal morphology and carbon/carbon composition of solid oxalate in cacti.

    PubMed

    Rivera, E R; Smith, B N

    1979-12-01

    Morphology, crystal structure, and carbon isotopic composition of calcium oxalate from representative species from the family Cactaceae were determined using scanning electron microscopy, x-ray diffraction, and isotope ratio mass spectrometry. Crystals from one species in the Opuntieae tribe of the Cactaceae were druses with acute points composed of the monohydrate form of calcium oxalate (whewellite). Crystals from three species in the Cereeae tribe were the dihydrate form of calcium oxalate (weddellite) forming druses made up of tetragonal and isodiametric crystallites. The oxalate was relatively enriched in (13)C isotope (-7.3 to - 8.7 per thousand) compared with woody fibers (-13.3 to 14.1 per thousand) from the same plants.

  19. Crystal Morphology and 13Carbon/12Carbon Composition of Solid Oxalate in Cacti 1

    PubMed Central

    Rivera, E. R.; Smith, B. N.

    1979-01-01

    Morphology, crystal structure, and carbon isotopic composition of calcium oxalate from representative species from the family Cactaceae were determined using scanning electron microscopy, x-ray diffraction, and isotope ratio mass spectrometry. Crystals from one species in the Opuntieae tribe of the Cactaceae were druses with acute points composed of the monohydrate form of calcium oxalate (whewellite). Crystals from three species in the Cereeae tribe were the dihydrate form of calcium oxalate (weddellite) forming druses made up of tetragonal and isodiametric crystallites. The oxalate was relatively enriched in 13C isotope (-7.3 to - 8.7 ‰) compared with woody fibers (-13.3 to 14.1 ‰) from the same plants. Images PMID:16661115

  20. LITERATURE REVIEW FOR OXALATE OXIDATION PROCESSES AND PLUTONIUM OXALATE SOLUBILITY

    SciTech Connect

    Nash, C.

    2012-02-03

    A literature review of oxalate oxidation processes finds that manganese(II)-catalyzed nitric acid oxidation of oxalate in precipitate filtrate is a viable and well-documented process. The process has been operated on the large scale at Savannah River in the past, including oxidation of 20 tons of oxalic acid in F-Canyon. Research data under a variety of conditions show the process to be robust. This process is recommended for oxalate destruction in H-Canyon in the upcoming program to produce feed for the MOX facility. Prevention of plutonium oxalate precipitation in filtrate can be achieved by concentrated nitric acid/ferric nitrate sequestration of oxalate. Organic complexants do not appear practical to sequester plutonium. Testing is proposed to confirm the literature and calculation findings of this review at projected operating conditions for the upcoming campaign. H Canyon plans to commence conversion of plutonium metal to low-fired plutonium oxide in 2012 for eventual use in the Mixed Oxide Fuel (MOX) Facility. The flowsheet includes sequential operations of metal dissolution, ion exchange, elution, oxalate precipitation, filtration, and calcination. All processes beyond dissolution will occur in HB-Line. The filtration step produces an aqueous filtrate that may have as much as 4 M nitric acid and 0.15 M oxalate. The oxalate needs to be removed from the stream to prevent possible downstream precipitation of residual plutonium when the solution is processed in H Canyon. In addition, sending the oxalate to the waste tank farm is undesirable. This report addresses the processing options for destroying the oxalate in existing H Canyon equipment.

  1. Nephrocalcinosis and hyperlipidemia in rats fed a cholesterol- and fat-rich diet: association with hyperoxaluria, altered kidney and bone minerals, and renal tissue phospholipid-calcium interaction.

    PubMed

    Schmiedl, A; Schwille, P O; Bonucci, E; Erben, R G; Grayczyk, A; Sharma, V

    2000-12-01

    To determine whether an "atherogenic" diet (excess of cholesterol and neutral fat) induces pathological calcification in various organs, including the kidney, and abnormal oxalate metabolism, 24 male Sprague-Dawley rats were fed either normal lab chow (controls, n = 12) or the cholesterol- and fat-rich experimental diet (CH-F, n = 12) for 111 +/- 3 days. CH-F rats developed dyslipidemia [high blood levels of triglycerides, total, low-density lipoprotein (LDL)-, very low-density lipoprotein (VLDL)-, high-density lipoprotein (HDL)-bound cholesterol, total phospholipids], elevated serum total alkaline phosphatase and lactate dehydrogenase (LDH) levels, in the absence of changes in overall renal function, extracellular mineral homeostasis [serum protein-corrected total calcium, magnesium, parathyroid hormone (PTH), 1,25-dihydroxyvitamin D (1,25(OH)2D)], plasma glycolate and oxalate levels. There was a redistribution of bone calcium and enhanced exchange of this within the extraosseous space, which was accompanied by significant bone calcium loss, but normal bone histomorphometry. Liver oxalate levels, if expressed per unit of defatted (DF) dry liver, were three times higher than in the controls. Urinary glycolate, oxalate, calcium and total protein excretion levels were elevated, the latter showing an excess of proteins > 100 kD and a deficit of proteins > 30-50 kD. Urinary calcium oxalate supersaturation was increased, and calcium phosphate supersaturation was unchanged. There were dramatically increased (by number, circumference, and area) renal calcium phosphate calcifications in the cortico-medullary region, but calcium oxalate deposits were not detectable. Electron microscopy (EM) and elemental analysis revealed intratubular calcium phosphate, apparently needle-like hydroxyapatite. Immunohistochemistry of renal tissue calcifications revealed co-localization of phospholipids and calcium phosphate. It is concluded that rats fed the CH-F diet exhibited: (1) a

  2. A theoretical and experimental study of calcium, iron, zinc, cadmium, and sodium ions absorption by aspartame.

    PubMed

    Mahnam, Karim; Raisi, Fatame

    2017-03-01

    Aspartame (L-Aspartyl-L-phenylalanine methyl ester) is a sweet dipeptide used in some foods and beverages. Experimental studies show that aspartame causes osteoporosis and some illnesses, which are similar to those of copper and calcium deficiency. This raises the issue that aspartame in food may interact with cations and excrete them from the body. This study aimed to study aspartame interaction with calcium, zinc, iron, sodium, and cadmium ions via molecular dynamics simulation (MD) and spectroscopy. Following a 480-ns molecular dynamics simulation, it became clear that the aspartame is able to sequester Fe(2+), Ca(2+), Cd(2+), and Zn(2+) ions for a long time. Complexation led to increasing UV-Vis absorption spectra and emission spectra of the complexes. This study suggests a potential risk of cationic absorption of aspartame. This study suggests that purification of cadmium-polluted water by aspartame needs a more general risk assessment.

  3. Pathogenesis and treatment of calcium stones.

    PubMed

    Parks, J H; Coe, F L

    1996-09-01

    Calcium stones arise from imbalances between urinary excretions of insoluble salts and water. Idiopathic hypercalciuria and hyperparathyroidism are the calcium disorders usually associated with elevated levels of calcium in the urine. Renal tubular acidosis is associated with a disordered acid-base status that results in low urine citrate. Hypocitraturia itself is a cause of calcium stones because it leaves urine calcium free to complex with either oxalate or phosphate. Elevated urine oxalate is commonly associated with dietary excesses, bowel disease, and, rarely, primary hyperoxaluria. Hyperuricosuria, usually of dietary origin, when reversed can cause a fall in new calcium stones.

  4. In vitro osteogenic/dentinogenic potential of an experimental calcium aluminosilicate cement

    PubMed Central

    Eid, Ashraf A.; Niu, Li-na; Primus, Carolyn M.; Opperman, Lynne A.; Watanabe, Ikuya; Pashley, David H.; Tay, Franklin R.

    2013-01-01

    Introduction Calcium aluminosilicate cements are fast-setting, acid-resistant, bioactive cements that may be used as root-repair materials. This study examined the osteogenic/dentinogenic potential of an experimental calcium aluminosilicate cement (Quick-Set) using a murine odontoblast-like cell model. Methods Quick-Set and white ProRoot MTA (WMTA) were mixed with the proprietary gel or deionized water, allowed to set completely in 100% relative humidity and aged in complete growth medium for 2 weeks until rendered non-cytotoxic. Similarly-aged Teflon discs were used as negative control. The MDPC-23 cell-line was used for evaluating changes in mRNA expressions of genes associated with osteogenic/dentinogenic differentiation and mineralization (qRT-PCR) alkaline phosphatase enzyme production and extracellular matrix mineralization (Alizarin red-S staining). Results After MDPC-23 cells were incubated with the materials in osteogenic differentiation medium for 1 week, both cements showed upregulation in ALP and DSPP expression. Fold increases in these two genes were not significantly different between Quick-Set and WMTA. Both cements showed no statistically significant upregulation/downregulation in RUNX2, OCN, BSP and DMP1 gene expression compared with Teflon. Alkaline phosphatase activity of cells cultured on Quick-Set and WMTA were not significantly different at 1 week or 2 weeks, but were significantly higher (p<0.05) than Teflon in both weeks. Both cements showed significantly higher calcium deposition compared with Teflon after 3 weeks of incubation in mineralizing medium (p<0.001). Differences between Quick-Set and WMTA were not statistically significant. Conclusions The experimental calcium aluminosilicate cement exhibits similar osteogenic/dentinogenic properties to WMTA and may be a potential substitute for commercially-available tricalcium silicate cements. PMID:23953291

  5. The fluorimetric determination of oxalic acid in blood and other biological materials

    PubMed Central

    Zarembski, P. M.; Hodgkinson, A.

    1965-01-01

    1. Oxalic acid is separated from interfering substances by extraction with tri-n-butyl phosphate followed by co-precipitation with calcium sulphate. The precipitated oxalic acid is then reduced to glyoxylic acid, which is coupled with resorcinol to form a coloured fluorescent complex. 2. The spectrofluorometric method described is sensitive and highly specific, the minimum detectable amount of oxalic acid being 0·9μmole under the recommended conditions. 3. The concentration of oxalic acid in blood from 15 normal adults was 200–320μg./100ml. For serum the range was 135–280μg./100ml. The urinary excretion of oxalic acid by 60 normal adults on a normal diet was 9·0–28·5mg./24hr. PMID:5862411

  6. Oxalate deposition on asbestos bodies.

    PubMed

    Ghio, Andrew J; Roggli, Victor L; Richards, Judy H; Crissman, Kay M; Stonehuerner, Jacqueline D; Piantadosi, Claude A

    2003-08-01

    We report on a deposition of oxalate crystals on ferruginous bodies after occupational exposure to asbestos demonstrated in 3 patients. We investigated the mechanism and possible significance of this deposition by testing the hypothesis that oxalate generated through nonenzymatic oxidation of ascorbate by asbestos-associated iron accounts for the deposition of the crystal on a ferruginous body. Crocidolite asbestos (1000 microg/mL) was incubated with 500 micromol H(2)O(2) and 500 micromol ascorbate for 24 hours at 22 degrees C. The dependence of oxalate generation on iron-catalyzed oxidant production was tested with the both the metal chelator deferoxamine and the radical scavenger dimethylthiourea. Incubation of crocidolite, H(2)O(2), and ascorbate in vitro generated approximately 42 nmol of oxalate in 24 hours. Oxalate generation was diminished significantly by the inclusion of either deferoxamine or dimethylthiourea in the reaction mixture. Incubation of asbestos bodies and uncoated fibers isolated from human lung with 500 micromol H(2)O(2) and 500 micromol ascorbate for 24 hours at 22 degrees C resulted in the generation of numerous oxalate crystals. We conclude that iron-catalyzed production of oxalate from ascorbate can account for the deposition of this crystal on ferruginous bodies.

  7. Acute oxalate nephropathy due to ‘Averrhoa bilimbi’ fruit juice ingestion

    PubMed Central

    Bakul, G.; Unni, V. N.; Seethaleksmy, N. V.; Mathew, A.; Rajesh, R.; Kurien, G.; Rajesh, J.; Jayaraj, P. M.; Kishore, D. S.; Jose, P. P.

    2013-01-01

    Irumban puli (Averrhoa bilimbi) is commonly used as a traditional remedy in the state of Kerala. Freshly made concentrated juice has a very high oxalic acid content and consumption carries a high risk of developing acute renal failure (ARF) by deposition of calcium oxalate crystals in renal tubules. Acute oxalate nephropathy (AON) due to secondary oxalosis after consumption of Irumban puli juice is uncommon. AON due to A. bilimbi has not been reported before. We present a series of ten patients from five hospitals in the State of Kerala who developed ARF after intake of I. puli fruit juice. Seven patients needed hemodialysis whereas the other three improved with conservative management. PMID:23960349

  8. Effect of different brewing times on soluble oxalate content of loose-packed black teas and tea bags.

    PubMed

    Mahdavi, Reza; Lotfi Yagin, Neda; Liebman, Michael; Nikniaz, Zeinab

    2013-02-01

    Because of the postulated role of increased dietary oxalate intake in calcium oxalate stone formation, the effect of different brewing times on soluble oxalate contents of loose-packed black tea and tea bags was studied. The oxalate content of 25 different samples of loose-packed black teas after brewing at 5, 10, 15, 30, and 60 min and of ten brands of tea bags after infusion for 1, 2, 3, 4, and 5 min was measured by enzymatic assay. The oxalate concentration resulting from different brewing times ranged from 4.3 to 6.2 mg/240 ml for loose-packed black teas and from 2.7 to 4.8 mg/240 ml for tea bags. There was a stepwise increase in oxalate concentration associated with increased brewing times.

  9. Oxalate Nephropathy in Systemic Sclerosis: Case Series and Review of the Literature

    PubMed Central

    Ligon, Colin B.; Hummers, Laura K.; McMahan, Zsuzsanna H.

    2015-01-01

    Objective To increase awareness of oxalate nephropathy as a cause of acute kidney injury (AKI) among systemic sclerosis patients with small intestinal dysmotility and malabsorption, and to prompt consideration of dietary modification and early treatment of predisposing causes of oxalate nephropathy in this population. Methods Two cases of biopsy-proven oxalate nephropathy were identified among systemic sclerosis patients in the course of direct clinical care. Subsequently, a retrospective search of the Johns Hopkins Pathology databases identified a third patient with systemic sclerosis who developed oxalate nephropathy. Results Among the three patients with qualifying biopsies, all three had systemic sclerosis with lower gastrointestinal involvement. All three presented with diarrhea, malabsorption, and AKI. In two of the three patients, diarrhea was present for at least two years before the development of AKI; in the third, incidental oxalate nephropathy was noted three years before she developed AKI and extensive oxalate nephropathy in the setting of a prolonged mycobacterium avium-intracellulare enteritis. In one case, oxalate crystals were present by urinalysis months before diagnosis by biopsy, in the second, hyperoxaluria was diagnosed by urine collection immediately after biopsy, and in the third, oxalate crystals had been noted incidentally on post-transplant renal biopsy three years before the development of fulminant oxalate nephropathy. All three patients died within a year of diagnosis. Conclusions Patients with systemic sclerosis and bowel dysmotility associated with chronic diarrhea and malabsorption may be at risk for an associated oxalate nephropathy. Regular screening of systemic sclerosis patients with small bowel malabsorption syndromes through routine urinalysis or 24 hour urine oxalate collection, should be considered. Further studies defining the prevalence of this complication in systemic sclerosis, the benefit of dietary modification on

  10. Bilateral native nephrectomy reduces systemic oxalate level after combined liver-kidney transplant: A case report.

    PubMed

    Villani, Vincenzo; Gupta, Neena; Elias, Nahel; Vagefi, Parsia A; Markmann, James F; Paul, Elahna; Traum, Avram Z; Yeh, Heidi

    2017-03-05

    Primary hyperoxaluria type 1 (PH1) is a rare liver enzymatic defect that causes overproduction of plasma oxalate. Accumulation of oxalate in the kidney and subsequent renal failure are fatal to PH1 patients often in pediatric age. Combined liver and kidney transplantation is the therapy of choice for end-stage renal disease due to PH1. Levels of plasma oxalate remain elevated for several months after liver transplantation, as the residual body oxalate is slowly excreted. Patients with persistent hyperoxaluria after transplant often require hemodialysis, and accumulation of residual oxalate in the kidney can induce graft dysfunction. As the native kidneys are the main target of calcium oxalate accumulation, we postulated that removal of native kidneys could drastically decrease total body oxalate levels after transplantation. Here, we report a case of bilateral nephrectomy at the time of combined liver-kidney transplantation in a pediatric PH1 patient. Bilateral nephrectomy induced a rapid decrease in plasma oxalate to normal levels in less than 20 days, compared to the several months reported in the literature. Our results suggest that removal of native kidneys could be an effective strategy to decrease the need for hemodialysis and the risk of renal dysfunction after combined liver-kidney transplantation in patients with PH1.

  11. Functional characterization of the oxaloacetase encoding gene and elimination of oxalate formation in the β-lactam producer Penicillium chrysogenum.

    PubMed

    Gombert, A K; Veiga, T; Puig-Martinez, M; Lamboo, F; Nijland, J G; Driessen, A J M; Pronk, J T; Daran, J M

    2011-08-01

    Penicillium chrysogenum is widely used as an industrial antibiotic producer, in particular in the synthesis of ß-lactam antibiotics such as penicillins and cephalosporins. In industrial processes, oxalic acid formation leads to reduced product yields. Moreover, precipitation of calcium oxalate complicates product recovery. We observed oxalate production in glucose-limited chemostat cultures of P. chrysogenum grown with or without addition of adipic acid, side-chain of the cephalosporin precursor adipoyl-6-aminopenicillinic acid (ad-6-APA). Oxalate accounted for up to 5% of the consumed carbon source. In filamentous fungi, oxaloacetate hydrolase (OAH; EC3.7.1.1) is generally responsible for oxalate production. The P. chrysogenum genome harbours four orthologs of the A. niger oahA gene. Chemostat-based transcriptome analyses revealed a significant correlation between extracellular oxalate titers and expression level of the genes Pc18g05100 and Pc22g24830. To assess their possible involvement in oxalate production, both genes were cloned in Saccharomyces cerevisiae, yeast that does not produce oxalate. Only the expression of Pc22g24830 led to production of oxalic acid in S. cerevisiae. Subsequent deletion of Pc22g28430 in P. chrysogenum led to complete elimination of oxalate production, whilst improving yields of the cephalosporin precursor ad-6-APA.

  12. Extracellular nucleotides inhibit oxalate transport by human intestinal Caco-2-BBe cells through PKC-δ activation.

    PubMed

    Amin, Ruhul; Sharma, Sapna; Ratakonda, Sireesha; Hassan, Hatim A

    2013-07-01

    Nephrolithiasis remains a major health problem in Western countries. Seventy to 80% of kidney stones are composed of calcium oxalate, and small changes in urinary oxalate affect risk of kidney stone formation. Intestinal oxalate secretion mediated by the anion exchanger SLC26A6 plays an essential role in preventing hyperoxaluria and calcium oxalate nephrolithiasis, indicating that understanding the mechanisms regulating intestinal oxalate transport is critical for management of hyperoxaluria. Purinergic signaling modulates several intestinal processes through pathways including PKC activation, which we previously found to inhibit Slc26a6 activity in mouse duodenal tissue. We therefore examined whether purinergic stimulation with ATP and UTP affects oxalate transport by human intestinal Caco-2-BBe (C2) cells. We measured [¹⁴C]oxalate uptake in the presence of an outward Cl⁻ gradient as an assay of Cl⁻/oxalate exchange activity, ≥50% of which is mediated by SLC26A6. We found that ATP and UTP significantly inhibited oxalate transport by C2 cells, an effect blocked by the PKC inhibitor Gö-6983. Utilizing pharmacological agonists and antagonists, as well as PKC-δ knockdown studies, we observed that ATP inhibits oxalate transport through the P2Y₂ receptor, PLC, and PKC-δ. Biotinylation studies showed that ATP inhibits oxalate transport by lowering SLC26A6 surface expression. These findings are of potential relevance to pathophysiology of inflammatory bowel disease-associated hyperoxaluria, where supraphysiological levels of ATP/UTP are expected and overexpression of the P2Y₂ receptor has been reported. We conclude that ATP and UTP inhibit oxalate transport by lowering SLC26A6 surface expression in C2 cells through signaling pathways including the P2Y₂ purinergic receptor, PLC, and PKC-δ.

  13. Experimental Calcium Silicate-Based Cement with and without Zirconium Oxide Modulates Fibroblasts Viability.

    PubMed

    Slompo, Camila; Peres-Buzalaf, Camila; Gasque, Kellen Cristina da Silva; Damante, Carla Andreotti; Ordinola-Zapata, Ronald; Duarte, Marco Antonio Hungaro; de Oliveira, Rodrigo Cardoso

    2015-01-01

    The aim of this study was to verify whether the use of zirconium oxide as a radiopacifier of an experimental calcium silicate-based cement (WPCZO) leads to cytotoxicity. Fibroblasts were treated with different concentrations (10 mg/mL, 1 mg/mL, and 0.1 mg/mL) of the cements diluted in Dulbecco's modified Eagle's medium (DMEM) for periods of 12, 24, and 48 h. Groups tested were white Portland cement (WPC), white Portland cement with zirconium oxide (WPCZO), and white mineral trioxide aggregate Angelus (MTA). Control group cells were not treated. The cytotoxicity was evaluated through mitochondrial-activity (MTT) and cell-density (crystal violet) assays. All cements showed low cytotoxicity. In general, at the concentration of 10 mg/mL there was an increase in viability of those groups treated with WPC and WPCZO when compared to the control group (p<0.05). A similar profile for the absorbance values was noted among the groups: 10 mg/mL presented an increase in viability compared to the control group. On the other hand, smaller concentrations presented a similar or lower viability compared to the control group, in general. A new dental material composed of calcium silicate-based cement with 20% zirconium oxide as the radiopacifier showed low cytotoxicity as a promising material to be exploited for root-end filling.

  14. The oxalate-carbonate pathway: at the interface between biology and geology

    NASA Astrophysics Data System (ADS)

    Junier, P.; Cailleau, G.; Martin, G.; Guggiari, M.; Bravo, D.; Clerc, M.; Aragno, M.; Job, D.; Verrecchia, E.

    2012-04-01

    The formation of calcite in otherwise carbonate-free acidic soils through the biological degradation of oxalate is a mechanism termed oxalate-carbonate pathway. This pathway lies at the interface between biological and geological systems and constitutes an important, although underestimated, soil mineral carbon sink. In this case, atmospheric CO2 is fixed by the photosynthetic activity of oxalogenic plants, which is partly destined to the production of oxalate used for the chelation of metals, and particularly, calcium. Fungi are also able to produce oxalate to cope with elevated concentrations of metals. In spite of its abundance as a substrate, oxalate is a very stable organic anion that can be metabolized only by a group of bacteria that use it as carbon and energy sources. These bacteria close the biological cycle by degrading calcium oxalate, releasing Ca2+ and inducing a change in local soil pH. If parameters are favourable, the geological part of the pathway begins, because this change in pH will indirectly lead to the precipitation of secondary calcium carbonate (calcite) in unexpected geological conditions. Due to the initial acidic soil conditions, and the absence of geological carbonate in the basement, it is unexpected to find C in the form of calcite. The activity of the oxalate-carbonate pathway has now been demonstrated in several places around the world, suggesting that its importance can be even greater than expected. In addition, new roles for each of the biological players of the pathway have been revealed recently forcing us to reconsider a global biogeochemical model for oxalate cycling.

  15. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    NASA Astrophysics Data System (ADS)

    Cailleau, G.; Braissant, O.; Verrecchia, E. P.

    2011-02-01

    An African oxalogenic tree, the iroko tree (Milicia excelsa), has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the theoretical acidic conditions of these soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from field to microscopic scales. In the first centimeters of the soil profile, decaying of the organic matter allows the release of whewellite crystals, mainly due to the action of termites and saprophytic fungi. Regarding the carbonate flux, another direct consequence of wood feeding is a concomitant flux of carbonate formed in wood tissues, which is not consumed by termites. Nevertheless, calcite biomineralization of the tree is not a consequence of in situ oxalate consumption, but rather related to the oxalate oxidation inside the upper part of the soil. The consequence of this oxidation is the presence of carbonate ions in the soil solution pumped through the roots, leading to preferential mineralization of the roots and the trunk base. An ideal scenario for the iroko biomineralization and soil carbonate accumulation starts with oxalatization: as the iroko tree grows, the organic matter flux to the soil constitutes the litter. Therefore, an oxalate pool is formed on the forest ground. Then, wood rotting gents (mainly termites, fungi, and bacteria) release significant amounts of oxalate crystals from decaying plant tissues. In addition some of these gents are themselves producers of oxalate (fungi). Both processes contribute to a soil pool of "available" oxalate crystals. Oxalate consumption by oxalotrophic bacteria can start. Carbonate and calcium ions present in the soil solution represent the end products of the oxalate-carbonate pathway. The solution is pumped through the

  16. Turning sunlight into stone: the oxalate-carbonate pathway in a tropical tree ecosystem

    NASA Astrophysics Data System (ADS)

    Cailleau, G.; Braissant, O.; Verrecchia, E. P.

    2011-07-01

    An African oxalogenic tree, the iroko tree (Milicia excelsa), has the property to enhance carbonate precipitation in tropical oxisols, where such accumulations are not expected due to the acidic conditions in these types of soils. This uncommon process is linked to the oxalate-carbonate pathway, which increases soil pH through oxalate oxidation. In order to investigate the oxalate-carbonate pathway in the iroko system, fluxes of matter have been identified, described, and evaluated from field to microscopic scales. In the first centimeters of the soil profile, decaying of the organic matter allows the release of whewellite crystals, mainly due to the action of termites and saprophytic fungi. In addition, a concomitant flux of carbonate formed in wood tissues contributes to the carbonate flux and is identified as a direct consequence of wood feeding by termites. Nevertheless, calcite biomineralization of the tree is not a consequence of in situ oxalate consumption, but rather related to the oxalate oxidation inside the upper part of the soil. The consequence of this oxidation is the presence of carbonate ions in the soil solution pumped through the roots, leading to preferential mineralization of the roots and the trunk base. An ideal scenario for the iroko biomineralization and soil carbonate accumulation starts with oxalatization: as the iroko tree grows, the organic matter flux to the soil constitutes the litter, and an oxalate pool is formed on the forest ground. Then, wood rotting agents (mainly termites, saprophytic fungi, and bacteria) release significant amounts of oxalate crystals from decaying plant tissues. In addition, some of these agents are themselves producers of oxalate (e.g. fungi). Both processes contribute to a soil pool of "available" oxalate crystals. Oxalate consumption by oxalotrophic bacteria can then start. Carbonate and calcium ions present in the soil solution represent the end products of the oxalate-carbonate pathway. The solution is

  17. Experimental Comparison of Calcium Sulfate (CaSO(4)) Scale Deposition on Coated Carbon Steel and Titanium Surfaces

    NASA Astrophysics Data System (ADS)

    Al-Otaibi, Dhawi AbdulRahman

    Calcium Sulfate (CaSO4) deposit reduces heat exchange in heat transfer equipment which adversely affects the equipment performance and plant production. This experimental study was conducted by using the Rotating Cylinder Electrode (RCE) equipment available in the university's Center for Engineering Research (CER/RI) to study and compare the effect of solution hydrodynamics on Calcium Sulfate (CaSO4) scale deposition on coated carbon steel and titanium surfaces. In addition, the Scanning Electron Microscopic was used to examine the morphology and distribution of Calcium Sulfate (CaSO 4) crystals deposited on titanium metal surfaces. In this study, the rotational speed was varied from 100 to 2000 RPM to study the behavior of Calcium Sulfate (CaSO4) accumulation on both materials. Based on the experimental results, Calcium Sulfate (CaSO4) scale obtained in the present study was almost constant on coated carbon steel in which the rate of scale deposition is equal to the rate of scale removal. However, the deposition of Calcium Sulfate (CaSO4) observed on titanium material was increased as the speed increased.

  18. Structural variability in neptunium(V) oxalate compounds: synthesis and structural characterization of Na2NpO2(C2O4)OH.H2O.

    PubMed

    Bean, Amanda C; Garcia, Eduardo; Scott, Brian L; Runde, Wolfgang

    2004-10-04

    Reaction of a (237)Np(V) stock solution in the presence of oxalic acid, calcium chloride, and sodium hydroxide under hydrothermal conditions produces single crystals of a neptunium(V) oxalate, Na(2)NpO(2)(C(2)O(4))OH.H(2)O. The structure consists of one-dimensional chains running down the a axis and is the first example of a neptunium(V) oxalate compound containing hydroxide anions.

  19. Relationship of otolith strontium-to-calcium ratios and salinity: Experimental validation for juvenile salmonids

    USGS Publications Warehouse

    Zimmerman, C.E.

    2005-01-01

    Analysis of otolith strontium (Sr) or strontium-to-calcium (Sr:Ca) ratios provides a powerful tool to reconstruct the chronology of migration among salinity environments for diadromous salmonids. Although use of this method has been validated by examination of known individuals and translocation experiments, it has never been validated under controlled experimental conditions. In this study, incorporation of otolith Sr was tested across a range of salinities and resulting levels of ambient Sr and Ca concentrations in juvenile chinook salmon (Oncorhynchus tshawytscha), coho salmon (Oncorhynchus kisutch), sockeye salmon (Oncorhynchus nerka), rainbow trout (Oncorhynchus rnykiss), and Arctic char (Salvelinus alpinus). Experimental water was mixed, using stream water and seawater as end members, to create experimental salinities of 0.1, 6.3, 12.7, 18.6, 25.5, and 33.0 psu. Otolith Sr and Sr:Ca ratios were significantly related to salinity for all species (r2 range: 0.80-0.91) but provide only enough predictive resolution to discriminate among fresh water, brackish water, and saltwater residency. These results validate the use of otolith Sr:Ca ratios to broadly discriminate salinity histories encountered by salmonids but highlight the need for further research concerning the influence of osmoregulation and physiological changes associated with smoking on otolith microchemistry.

  20. [Factors which influence the size of calcium oxalat crystals during their formation from saturated solutions].

    PubMed

    Hartung, R; Leskovar, P

    1978-07-01

    The nucleation and growth of Ca-oxalate crystals from metastable and instable solutions was studied in some detail to find out the dependence of the crystal size on the absolute calcium resp. oxalate concentration, further on their molar ratio, on the presence resp. absence of crystal seeds, on the agitation resp. stagnation of the Ca-oxalate solution, on the duration of crystallization and on the renewing of the Ca-oxalate containing supernatant, thus simulating a prolonged (dietary) oxalate load in vivo. The most important findings are the clear inhibition of crystal growth at higher and very high calcium concentrations (in contrary to the unhindered crystal enlargement at high oxalate concentrations), further the eminent role of the oxalate in the formation of big crystals and crystal aggregates, as well as the substantial crystal enlargement at the persistent oxalate load.

  1. The effect of rumen adaptation to oxalic acid on selection of oxalic-acid-rich plants by goats.

    PubMed

    Duncan, A J; Frutos, P; Young, S A

    2000-01-01

    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.

  2. The role of intestinal oxalate transport in hyperoxaluria and the formation of kidney stones in animals and man.

    PubMed

    Whittamore, Jonathan M; Hatch, Marguerite

    2017-02-01

    The intestine exerts a considerable influence over urinary oxalate in two ways, through the absorption of dietary oxalate and by serving as an adaptive extra-renal pathway for elimination of this waste metabolite. Knowledge of the mechanisms responsible for oxalate absorption and secretion by the intestine therefore have significant implications for understanding the etiology of hyperoxaluria, as well as offering potential targets for future treatment strategies for calcium oxalate kidney stone disease. In this review, we present the recent developments and advances in this area over the past 10 years, and put to the test some of the new ideas that have emerged during this time, using human and mouse models. A key focus for our discussion are the membrane-bound anion exchangers, belonging to the SLC26 gene family, some of which have been shown to participate in transcellular oxalate absorption and secretion. This has offered the opportunity to not only examine the roles of these specific transporters, revealing their importance to oxalate homeostasis, but to also probe the relative contributions made by the active transcellular and passive paracellular components of oxalate transport across the intestine. We also discuss some of the various physiological stimuli and signaling pathways which have been suggested to participate in the adaptation and regulation of intestinal oxalate transport. Finally, we offer an update on research into Oxalobacter formigenes, alongside recent investigations of other oxalate-degrading gut bacteria, in both laboratory animals and humans.

  3. Blockage of mitochondrial calcium uniporter prevents iron accumulation in a model of experimental subarachnoid hemorrhage

    SciTech Connect

    Yan, Huiying; Hao, Shuangying; Sun, Xiaoyan; Zhang, Dingding; Gao, Xin; Yu, Zhuang; Li, Kuanyu; Hang, Chun-Hua

    2015-01-24

    Highlights: • Iron accumulation was involved in the acute phase following SAH. • Blockage of MCU could attenuate cellular iron accumulation following SAH. • Blockage of MCU could decrease ROS generation and improve cell energy supply following SAH. • Blockage of MCU could alleviate apoptosis and brain injury following SAH. - Abstract: Previous studies have shown that iron accumulation is involved in the pathogenesis of brain injury following subarachnoid hemorrhage (SAH) and chelation of iron reduced mortality and oxidative DNA damage. We previously reported that blockage of mitochondrial calcium uniporter (MCU) provided benefit in the early brain injury after experimental SAH. This study was undertaken to identify whether blockage of MCU could ameliorate iron accumulation-associated brain injury following SAH. Therefore, we used two reagents ruthenium red (RR) and spermine (Sper) to inhibit MCU. Sprague–Dawley (SD) rats were randomly divided into four groups including sham, SAH, SAH + RR, and SAH + Sper. Biochemical analysis and histological assays were performed. The results confirmed the iron accumulation in temporal lobe after SAH. Interestingly, blockage of MCU dramatically reduced the iron accumulation in this area. The mechanism was revealed that inhibition of MCU reversed the down-regulation of iron regulatory protein (IRP) 1/2 and increase of ferritin. Iron–sulfur cluster dependent-aconitase activity was partially conserved when MCU was blocked. In consistence with this and previous report, ROS levels were notably reduced and ATP supply was rescued; levels of cleaved caspase-3 dropped; and integrity of neurons in temporal lobe was protected. Taken together, our results indicated that blockage of MCU could alleviate iron accumulation and the associated injury following SAH. These findings suggest that the alteration of calcium and iron homeostasis be coupled and MCU be considered to be a therapeutic target for patients suffering from SAH.

  4. Effect of Kimchi Fermentation on Oxalate Levels in Silver Beet (Beta vulgaris var. cicla).

    PubMed

    Wadamori, Yukiko; Vanhanen, Leo; Savage, Geoffrey P

    2014-04-23

    Total, soluble and insoluble oxalates were extracted and analyzed by high performance liquid chromatography (HPLC) following the preparation of kimchi using silver beet (Beta vulgaris var. cicla) stems and leaves. As silver beet contains high oxalate concentrations and consumption of high levels can cause the development of kidney stones in some people, the reduction of oxalate during preparation and fermentation of kimchi was investigated. The silver beet stems and leaves were soaked in a 10% brine solution for 11 h and then washed in cold tap water. The total, soluble and insoluble oxalate contents of the silver beet leaves were reduced by soaking in brine, from 4275.81 ± 165.48 mg/100 g to 3709.49 ± 216.51 mg/100 g fresh weight (FW). Fermenting the kimchi for 5 days at 19.3 ± 0.8 °C in 5 L ceramic jars with a water airtight seal resulted in a mean 38.50% reduction in total oxalate content and a mean 22.86% reduction in soluble oxalates. The total calcium content was essentially the same before and after the fermentation of the kimchi (mean 296.1 mg/100 g FW). The study showed that fermentation of kimchi significantly (p < 0.05) reduced the total oxalate concentration in the initial mix from 609.32 ± 15.69 to 374.71 ± 7.94 mg/100 g FW in the final mix which led to a 72.3% reduction in the amount of calcium bound to insoluble oxalate.

  5. An understanding of renal stone development in a mixed oxalate-phosphate system.

    PubMed

    Guan, Xiangying; Wang, Lijun; Dosen, Anja; Tang, Ruikang; Giese, Rossman F; Giocondi, Jennifer L; Orme, Christine A; Hoyer, John R; Nancollas, George H

    2008-07-15

    The in vivo formation of calcium oxalate concretions having calcium phosphate nidi is simulated in an in vitro (37 degrees C, pH 6.0) dual constant composition (DCC) system undersaturated (sigma DCPD = -0.330) with respect to brushite (DCPD, CaHPO 4 . 2H 2O) and slightly supersaturated (sigma COM = 0.328) with respect to calcium oxalate monohydrate (COM, CaC2O4 . H2O). The brushite dissolution provides calcium ions that raise the COM supersaturation, which is heterogeneously nucleated either on or near the surface of the dissolving calcium phosphate crystals. The COM crystallites may then aggregate, simulating kidney stone formation. Interestingly, two intermediate phases, anhydrous dicalcium phosphate (monetite, CaHPO4) and calcium oxalate trihydrate (COT), are also detected by X-ray diffraction during this brushite-COM transformation. In support of clinical observations, the results of these studies demonstrate the participation of calcium phosphate phases in COM crystallization providing a possible physical chemical mechanism for kidney stone formation.

  6. Tamm-Horsfall glycoprotein and calcium nephrolithiasis.

    PubMed

    Hess, B

    1994-01-01

    Available data on the effects of Tamm-Horsfall glycoprotein (THP) on calcium oxalate crystallization processes are apparently conflicting. With the main emphasis on calcium oxalate crystal aggregation, this review demonstrates that THP has a dual role as a modifier of crystal aggregation: in solutions with high pH, low ionic strength (IS) and low concentrations of calcium and THP itself, the glycoprotein acts as a powerful inhibitor of calcium oxalate crystal aggregation. Conversely, low pH, high IS and high concentrations of calcium and THP all favor self-aggregation of THP molecules which lowers their inhibitory activity against calcium oxalate crystal aggregation. Some patients with severely recurrent Ca stone disease excrete abnormal THPs which self-aggregate at levels of pH, IS and concentrations of Ca and THP at which normal THPs remain in monomeric form. With high Ca concentrations, such abnormal THPs become strong promoters of crystal aggregation, since conformational changes in crystal-bound THP molecules induce strong viscous binding forces which overcome repulsive electrostatic surface charges. By chelating free Ca ions, citrate reduces self-aggregation of THP molecules and turns promoting THPs into inhibitors of calcium oxalate crystal aggregation.

  7. Modeling aqueous ozone/UV process using oxalic acid as probe chemical.

    PubMed

    Garoma, Temesgen; Gurol, Mirat D

    2005-10-15

    A kinetic model that describes the removal of organic pollutants by an ozone/UV process is described. Oxalic acid, which reacts with a very low rate constant with ozone and relatively high rate constant with hydroxyl radical (OH*), was used as the probe chemical to model the process. The model was verified by experimental data on concentrations of oxalic acid and hydrogen peroxide (H202) under various experimental conditions, i.e., ozone gas dosage, UV light intensity, and varying oxalic acid concentrations.

  8. Genetically engineered Lactobacillus plantarum WCFS1 constitutively secreting heterologous oxalate decarboxylase and degrading oxalate under in vitro.

    PubMed

    Sasikumar, Ponnusamy; Gomathi, Sivasamy; Anbazhagan, Kolandaswamy; Baby, A Ebenezer; Sangeetha, J; Selvam, Govindan Sadasivam

    2014-11-01

    Hyperoxaluria is a major risk factor for urinary stone disease, where calcium oxalate (CaOx) is the most prevalent type of kidney stones. Systemic treatments of CaOx kidney stone patients are limited and comprise drawbacks including recurrence of stone formation and kidney damages. In the present work Lactobacillus plantarum (L. plantarum) was engineered to constitutively secrete oxalate decarboxylase (OxdC) for the degradation of intestinal oxalate. The homologous promoter PldhL and signal peptide Lp_0373 of L. plantarum were used for constructing recombinant vector pLdhl0373OxdC. Results showed that homologous promoter PldhL and signal peptide Lp_0373 facilitated the production, secretion, and functional expression of OxdC protein in L. plantarum. SDS-PAGE analysis revealed that 44 kDa protein OxdC was seen exceptionally in the culture supernatant of recombinant L. plantarum (WCFS1OxdC) harboring the plasmid pLdhl0373OxdC.The culture supernatant of L. plantarum WCFS1OxdC showed OxdC activity of 0.06 U/mg of protein, whereas no enzyme activity was observed in the supernatant of the wild type WCFS1 and the recombinant NC8OxdC strains. The purified recombinant OxdC from the WCFS1OxdC strain showed an activity of 19.1 U/mg protein. The recombinant L. plantarum strain secreted 25 % of OxdC protein in the supernatant. The recombinant strain degraded more than 70 % of soluble oxalate in the culture supernatant. Plasmid segregation analysis revealed that the recombinant strain lost almost 70-89 % of plasmid in 42nd and 84th generation, respectively. In conclusion, recombinant L. plantarum strain containing plasmid pLdhl0373OxdC showed constitutive secretion of bioactive OxdC and also capable of degrading externally available oxalate under in vitro conditions.

  9. Experimental Determination of the Formation Enthalpy of Calcium Cobaltate from Sol-Gel Precursors

    NASA Astrophysics Data System (ADS)

    Holgate, T. C.; Wu, N.; Nong, N. V.; Pryds, N.

    2017-02-01

    Calcium cobaltate (Ca3Co4O9) remains one of the most promising p-type oxide materials for high-temperature thermoelectric energy conversion. While much progress has been made in refining our understanding of the unique structure of the material, as well as optimization of the transport properties for thermoelectric efficiency, there remains a gap in the knowledge, both experimental and theoretical, of the thermodynamics of the system. Presented herein is an analysis of the heat of formation of the Ca3Co4O9 phase from sol-gel precursors using a highly sensitive differential scanning calorimeter, as well as observations of its decomposition into the Ca3Co2O6 phase. The reaction enthalpy of forming Ca3Co4O9 from CaCO3 and Co3O4 sol-gel precursors was determined to be +284 (±2%) kJ/mol, leading to a standard enthalpy of Ca3Co4O9 of -3307 (±3.5%) kJ/mol.

  10. Combining modelling and experimental approaches to explain how calcium signatures are decoded by calmodulin-binding transcription activators (CAMTAs) to produce specific gene expression responses.

    PubMed

    Liu, Junli; Whalley, Helen J; Knight, Marc R

    2015-10-01

    Experimental data show that Arabidopsis thaliana is able to decode different calcium signatures to produce specific gene expression responses. It is also known that calmodulin-binding transcription activators (CAMTAs) have calmodulin (CaM)-binding domains. Therefore, the gene expression responses regulated by CAMTAs respond to calcium signals. However, little is known about how different calcium signatures are decoded by CAMTAs to produce specific gene expression responses. A dynamic model of Ca(2+) -CaM-CAMTA binding and gene expression responses is developed following thermodynamic and kinetic principles. The model is parameterized using experimental data. Then it is used to analyse how different calcium signatures are decoded by CAMTAs to produce specific gene expression responses. Modelling analysis reveals that: calcium signals in the form of cytosolic calcium concentration elevations are nonlinearly amplified by binding of Ca(2+) , CaM and CAMTAs; amplification of Ca(2+) signals enables calcium signatures to be decoded to give specific CAMTA-regulated gene expression responses; gene expression responses to a calcium signature depend upon its history and accumulate all the information during the lifetime of the calcium signature. Information flow from calcium signatures to CAMTA-regulated gene expression responses has been established by combining experimental data with mathematical modelling.

  11. Urolithiasis in a herd of beef cattle associated with oxalate ingestion.

    PubMed

    Waltner-Toews, D; Meadows, D H

    1980-02-01

    An unusually high incidence of urinary calculi in a group of feeder cattle is described. Necropsy findings in one affected animal suggested that oxalates in the feed, specifically in fescue (Festuca spp.) seed screenings, may have been the cause. Low dietary calcium and decreased water intake by the cattle appear to have been predisposing factors. Control measures are discussed.

  12. Membrane Potential and Calcium Dynamics in Beta Cells from Mouse Pancreas Tissue Slices: Theory, Experimentation, and Analysis

    PubMed Central

    Dolenšek, Jurij; Špelič, Denis; Skelin Klemen, Maša; Žalik, Borut; Gosak, Marko; Slak Rupnik, Marjan; Stožer, Andraž

    2015-01-01

    Beta cells in the pancreatic islets of Langerhans are precise biological sensors for glucose and play a central role in balancing the organism between catabolic and anabolic needs. A hallmark of the beta cell response to glucose are oscillatory changes of membrane potential that are tightly coupled with oscillatory changes in intracellular calcium concentration which, in turn, elicit oscillations of insulin secretion. Both membrane potential and calcium changes spread from one beta cell to the other in a wave-like manner. In order to assess the properties of the abovementioned responses to physiological and pathological stimuli, the main challenge remains how to effectively measure membrane potential and calcium changes at the same time with high spatial and temporal resolution, and also in as many cells as possible. To date, the most wide-spread approach has employed the electrophysiological patch-clamp method to monitor membrane potential changes. Inherently, this technique has many advantages, such as a direct contact with the cell and a high temporal resolution. However, it allows one to assess information from a single cell only. In some instances, this technique has been used in conjunction with CCD camera-based imaging, offering the opportunity to simultaneously monitor membrane potential and calcium changes, but not in the same cells and not with a reliable cellular or subcellular spatial resolution. Recently, a novel family of highly-sensitive membrane potential reporter dyes in combination with high temporal and spatial confocal calcium imaging allows for simultaneously detecting membrane potential and calcium changes in many cells at a time. Since the signals yielded from both types of reporter dyes are inherently noisy, we have developed complex methods of data denoising that permit for visualization and pixel-wise analysis of signals. Combining the experimental approach of high-resolution imaging with the advanced analysis of noisy data enables novel

  13. Membrane Potential and Calcium Dynamics in Beta Cells from Mouse Pancreas Tissue Slices: Theory, Experimentation, and Analysis.

    PubMed

    Dolenšek, Jurij; Špelič, Denis; Klemen, Maša Skelin; Žalik, Borut; Gosak, Marko; Rupnik, Marjan Slak; Stožer, Andraž

    2015-10-28

    Beta cells in the pancreatic islets of Langerhans are precise biological sensors for glucose and play a central role in balancing the organism between catabolic and anabolic needs. A hallmark of the beta cell response to glucose are oscillatory changes of membrane potential that are tightly coupled with oscillatory changes in intracellular calcium concentration which, in turn, elicit oscillations of insulin secretion. Both membrane potential and calcium changes spread from one beta cell to the other in a wave-like manner. In order to assess the properties of the abovementioned responses to physiological and pathological stimuli, the main challenge remains how to effectively measure membrane potential and calcium changes at the same time with high spatial and temporal resolution, and also in as many cells as possible. To date, the most wide-spread approach has employed the electrophysiological patch-clamp method to monitor membrane potential changes. Inherently, this technique has many advantages, such as a direct contact with the cell and a high temporal resolution. However, it allows one to assess information from a single cell only. In some instances, this technique has been used in conjunction with CCD camera-based imaging, offering the opportunity to simultaneously monitor membrane potential and calcium changes, but not in the same cells and not with a reliable cellular or subcellular spatial resolution. Recently, a novel family of highly-sensitive membrane potential reporter dyes in combination with high temporal and spatial confocal calcium imaging allows for simultaneously detecting membrane potential and calcium changes in many cells at a time. Since the signals yielded from both types of reporter dyes are inherently noisy, we have developed complex methods of data denoising that permit for visualization and pixel-wise analysis of signals. Combining the experimental approach of high-resolution imaging with the advanced analysis of noisy data enables novel

  14. Calcium diffusivity in alumino-silicate garnets: an experimental and ATEM study

    NASA Astrophysics Data System (ADS)

    Vielzeuf, D.; Baronnet, A.; Perchuk, A. L.; Laporte, D.; Baker, M. B.

    2007-08-01

    Concentration gradients in calcium are common in metamorphic or magmatic garnets and can be used to determine the timescales of geological processes. However, the kinetics of Ca diffusion in garnet is poorly constrained and experimental studies have to date yielded widely varying diffusion coefficients. In this paper, we describe a new method for generating diffusion profiles in garnet. We incorporated polished and compositionally homogeneous garnet seeds in a finely ground powder of clinopyroxene and garnet. During the experiments (1.3 GPa, 1,050-1,250°C, and ƒO2 ≤ the graphite-O2 buffer), the mineral powder partially melted, recrystallized, and formed a 10-50 μm wide overgrowth zone of compositionally distinct garnet around the seeds. Long duration experiments generated measurable relaxation profiles at these seed/overgrowth interfaces. We performed analytical transmission electron microscope traverses across the interfaces in each experiment. Thirteen usable compositional profiles were obtained with characteristic distances of diffusion ranging from 300 to 1,000 nm. From these profiles, Ca-(Fe, Mg) interdiffusion coefficients were retrieved using an analytical solution for the diffusion equation and the data were cast in an Arrhenius relation. Linear regression of the data yields an activation energy Q Ca-(Fe, Mg) equal to 188 ± 48 kJ mol-1 and a frequency factor D 0 equal to 6.6 × 10-14 m2 s-1. Within the compositional range studied, the composition of garnet has no major effect on the Ca-(Fe, Mg) interdiffusion coefficient. The very slow diffusion rate of Ca is in agreement with natural observations indicating that Ca diffuses more slowly than Fe and Mg. The Ca diffusion coefficients derived from this study are not model-dependent and can be used to determine the durations of geological events from Ca relaxation profiles in natural garnets.

  15. Interaction between oxalic acid and titania in aqueous ethanol dispersions.

    PubMed

    Dahlsten, Per; Rosenholm, Jarl B

    2013-02-15

    The charging effects resulting from adsorption of oxalic acid and oxalate anions on titania (anatase) surfaces in anhydrous or mixed water-ethanol suspensions is summarized. The suddenly enhanced electrical conductance with respect to titania free solutions has previously been explained in terms of surface-induced electrolytic dissociation (SIED) of weak acids. A recently published model has previously been found to successfully characterize the complex SIED effect. The model is evaluated experimentally by recording the conductance and pH of the dispersion and the zeta potential of the particles. The experimental results can be condensed to master curves, which reveal the major properties of the systems and facilitate further modeling of extensive experimental results. The equilibrium and transport properties of solutions and particles were related, but different mechanisms was found to be active in each case. The results suggest that at least three adsorption equilibria should be considered in order to improve the model.

  16. OXALATE FORMATION FROM GLYOXAL IN ERYTHROCYTES

    PubMed Central

    Knight, John; Wood, Kyle D.; Lange, Jessica N.; Assimos, Dean G.; Holmes, Ross P.

    2015-01-01

    OBJECTIVES To determine whether glyoxal can be converted to oxalate in human erythrocytes. Glyoxal synthesis is elevated in diabetes, cardiovascular disease and other diseases with significant oxidative stress. Erythrocytes are a good model system for such studies as they lack intracellular organelles and have a simplified metabolism. METHODS Erythrocytes were isolated from healthy volunteers and incubated with varying concentrations of glyoxal for different amounts of time. Metabolic inhibitors were used to help characterize metabolic steps. The conversion of glyoxal to glycolate and oxalate in the incubation medium was determined by chromatographic techniques. RESULTS The bulk of the glyoxal was converted to glycolate but ~1% was converted to oxalate. Inclusion of the pro-oxidant, menadione, in the medium increased oxalate synthesis, and the inclusion of disulfiram, an inhibitor of aldehyde dehydrogenase activity, decreased oxalate synthesis. CONCLUSIONS The glyoxalase system, which utilizes glutathione as a cofactor, converts the majority of the glyoxal taken up by erythrocytes to glycolate but a small portion is converted to oxalate. A reduction in intracellular glutathione increases oxalate synthesis and a decrease in aldehyde dehydrogenase activity lowers oxalate synthesis and suggests that glyoxylate is an intermediate. Thus, oxidative stress in tissues could potentially increase oxalate synthesis. PMID:26546809

  17. Morphologies and elemental compositions of calcium crystals in phyllodes and branchlets of Acacia robeorum (Leguminosae: Mimosoideae)

    PubMed Central

    He, Honghua; Bleby, Timothy M.; Veneklaas, Erik J.; Lambers, Hans; Kuo, John

    2012-01-01

    Background and Aims Formation of calcium oxalate crystals is common in the plant kingdom, but biogenic formation of calcium sulfate crystals in plants is rare. We investigated the morphologies and elemental compositions of crystals found in phyllodes and branchlets of Acacia robeorum, a desert shrub of north-western Australia. Methods Morphologies of crystals in phyllodes and branchlets of A. robeorum were studied using scanning electron microscopy (SEM), and elemental compositions of the crystals were identified by energy-dispersive X-ray spectroscopy. Distributional patterns of the crystals were studied using optical microscopy together with SEM. Key Results According to the elemental compositions, the crystals were classified into three groups: (1) calcium oxalate; (2) calcium sulfate, which is a possible mixture of calcium sulfate and calcium oxalate with calcium sulfate being the major component; and (3) calcium sulfate · magnesium oxalate, presumably mixtures of calcium sulfate, calcium oxalate, magnesium oxalate and silica. The crystals were of various morphologies, including prisms, raphides, styloids, druses, crystal sand, spheres and clusters. Both calcium oxalate and calcium sulfate crystals were observed in almost all tissues, including mesophyll, parenchyma, sclerenchyma (fibre cells), pith, pith ray and cortex; calcium sulfate · magnesium oxalate crystals were only found in mesophyll and parenchyma cells in phyllodes. Conclusions The formation of most crystals was biologically induced, as confirmed by studying the crystals formed in the phyllodes from seedlings grown in a glasshouse. The crystals may have functions in removing excess calcium, magnesium and sulfur, protecting the plants against herbivory, and detoxifying aluminium and heavy metals. PMID:22294477

  18. Polynomial dual energy inverse functions for bone Calcium/Phosphorus ratio determination and experimental evaluation.

    PubMed

    Sotiropoulou, P; Fountos, G; Martini, N; Koukou, V; Michail, C; Kandarakis, I; Nikiforidis, G

    2016-12-01

    An X-ray dual energy (XRDE) method was examined, using polynomial nonlinear approximation of inverse functions for the determination of the bone Calcium-to-Phosphorus (Ca/P) mass ratio. Inverse fitting functions with the least-squares estimation were used, to determine calcium and phosphate thicknesses. The method was verified by measuring test bone phantoms with a dedicated dual energy system and compared with previously published dual energy data. The accuracy in the determination of the calcium and phosphate thicknesses improved with the polynomial nonlinear inverse function method, introduced in this work, (ranged from 1.4% to 6.2%), compared to the corresponding linear inverse function method (ranged from 1.4% to 19.5%).

  19. [Catalytic ozonation by ceramic honeycomb for the degradation of oxalic acid in aqueous solution].

    PubMed

    Zhao, Lei; Sun, Zhi-Zhong; Ma, Jun

    2007-11-01

    Comparative experiments for the degradation of oxalic acid in aqueous solution were carried out in the three processes of ozonation alone, ceramic honeycomb-catalyzed ozonation and ceramic honeycomb adsorption. The results show that the degradation rates of oxalic acid in the ceramic honeycomb-catalyzed ozonation, ozonation alone and ceramic honeycomb adsorption systems are 37.6%, 2.2% and 0.4%, and the presence of ceramic honeycomb catalyst significantly improves the degradation rate of oxalic acid compared to the results from non-catalytic ozonation and adsorption. With the addition of tert-butanol, the degradation rates of oxalic acid in catalytic ozonation system decrease by 24.1%, 29.0% and 30.1%, respectively, at the concentration of 5, 10 and 15 mg x L(-1). This phenomenon indicates that ceramic honeycomb-catalyzed ozonation for the degradation of oxalic acid in aqueous solution follows the mechanism of *OH oxidation, namely the heterogeneous surface of catalyst enhances the initiation of *OH. The results of TOC analysis demonstrate that the process of ceramic honeycomb-catalyzed ozonation can achieve the complete mineralization level without the formation of intermediary degradation products. The experimental results suggest that the reaction temperature has positive relationship with the degradation rate of oxalic acid. The degradation rates of oxalic acid in the ceramic honeycomb-catalyzed ozonation system are 16.4%, 37.6%, 61.3% and 68.2%, at the respective reaction temperature of 10, 20, 30 and 40 degrees C.

  20. Effect of waters of crystallization on terahertz spectra: anhydrous oxalic acid and its dihydrate.

    PubMed

    King, Matthew D; Korter, Timothy M

    2010-07-08

    Oxalic acid and oxalic acid dihydrate were studied using terahertz spectroscopy and solid-state density functional theory (DFT) in the spectral range 10-100 cm(-1). The size of the oxalic acid molecule and its limited internal degrees of freedom make it ideal for evaluating the performance of computational methods for the structural and dynamical simulation of strongly hydrogen-bonded solids. Calculations of the solid-state structures and terahertz spectra of oxalic acid and oxalic acid dihydrate were performed using the hybrid B3LYP and B3PW91 and the nonhybrid BLYP and PW91 density functionals employing the 6-311G(2d,2p) basis set. When these simulations were compared to the experimental spectra of the oxalic acid solids, a constant overprediction of the dihydrate frequencies was observed in contrast to the results of the anhydrous system. This change in behavior is connected to the nature of the vibrational motions being accessed. The primary molecular motion contributions to the terahertz vibrations of oxalic acid dihydrate were found to originate in the external motions of the cocrystallized H(2)O molecules. The observed overestimation of the vibrational energies in the simulated terahertz spectra is attributed to increased anharmonicity of the vibrational motions in the dihydrate system versus the anhydrous, resulting from weaker hydrogen bonding through the networked water molecules.

  1. Fungi, bacteria and soil pH: the oxalate-carbonate pathway as a model for metabolic interaction.

    PubMed

    Martin, Gaëtan; Guggiari, Matteo; Bravo, Daniel; Zopfi, Jakob; Cailleau, Guillaume; Aragno, Michel; Job, Daniel; Verrecchia, Eric; Junier, Pilar

    2012-11-01

    The oxalate-carbonate pathway involves the oxidation of calcium oxalate to low-magnesium calcite and represents a potential long-term terrestrial sink for atmospheric CO(2). In this pathway, bacterial oxalate degradation is associated with a strong local alkalinization and subsequent carbonate precipitation. In order to test whether this process occurs in soil, the role of bacteria, fungi and calcium oxalate amendments was studied using microcosms. In a model system with sterile soil amended with laboratory cultures of oxalotrophic bacteria and fungi, the addition of calcium oxalate induced a distinct pH shift and led to the final precipitation of calcite. However, the simultaneous presence of bacteria and fungi was essential to drive this pH shift. Growth of both oxalotrophic bacteria and fungi was confirmed by qPCR on the frc (oxalotrophic bacteria) and 16S rRNA genes, and the quantification of ergosterol (active fungal biomass) respectively. The experiment was replicated in microcosms with non-sterilized soil. In this case, the bacterial and fungal contribution to oxalate degradation was evaluated by treatments with specific biocides (cycloheximide and bronopol). Results showed that the autochthonous microflora oxidized calcium oxalate and induced a significant soil alkalinization. Moreover, data confirmed the results from the model soil showing that bacteria are essentially responsible for the pH shift, but require the presence of fungi for their oxalotrophic activity. The combined results highlight that the interaction between bacteria and fungi is essential to drive metabolic processes in complex environments such as soil.

  2. Experimental study and thermodynamic modelling of the calcium oxide-silicon oxide-aluminum oxide-calcium fluoride system

    NASA Astrophysics Data System (ADS)

    Kim, Dong-Geun

    of the CaO-CaF 2 binary system, which the literature data differ from each other by up to 50 mol %, was confirmed. The CaO solubility in solid CaF2 was found for the first time and reaches about 5 mol % at the eutectic temperature. The liquidus of the CaO-Al2O3-CaF2 and CaO-SiO 2-CaF2 systems were carefully studied and the miscibility gap in the CaO-Al2O3-CaF2 system was proved to be much smaller than that reported in literature. Also, thermal analysis was performed using DSC in a Pt crucible. The eutectic temperatures of the CaO-CaF2 and CaAl2O4-CaF2 systems were successfully measured and the alpha to beta-CaF2 polymorphic transition was confirmed. Based on the new experimental data and reliable literature data, thermodynamic modeling of the CaO-SiO2-Al 2O3-CaF2 system was also carried out. The results of thermodynamic calculation can be very beneficial for new mould flux design.

  3. Thermal Decomposition of Lanthanide, Yttrium, and Scandium Oxalates and Carbonates

    NASA Astrophysics Data System (ADS)

    Sharov, Vyacheslav A.; Bezdenezhnykh, G. V.

    1981-07-01

    Data concerning the thermal decomposition of lanthanide, yttrium, and scandium oxalates and carbonates are surveyed. The complexity of the process, the large number of stages involved, and the dependence of the composition of the intermediates in the thermal transformations on the experimental conditions is noted. Certain process characteristics have been discovered and it is concluded that the decomposition process depends on the ionic radius of the metal. The bibliography includes 83 references.

  4. Measurements of oxalic acid, oxalates, malonic acid, and malonates in atmospheric particulates.

    PubMed

    Yang, Liming; Yu, Liya E

    2008-12-15

    This study systematically examined effects of analytical approaches on resultant concentrations of oxalic acid, oxalates, malonic acid, and malonates. Results demonstrated that employing separate water extraction and THF extraction is required to properly quantify dicarboxylic acids vs dicarboxylates using IC or GC-MS. Applications of the recommended methods to analyze PM2.5 collected in Singapore showed that concentrations of oxalate ranged from 361.4 to 481.4 ng m(-3), which were 10-14.7 times higher than that of oxalic acid. Unlike that of oxalates, malonate concentrations (10.5-23.4 ng m(-3)) were no more than half of malonic acid concentration (43.8-53.9 ng m(-3)) in PM2.5. Concentration ratios of oxalate-to-oxalic acid and malonate-to-malonic acid obtained from this work were applied to reported literature data; as a first approximation, in urban environments similar to that in Singapore, quantifiable oxalic acid, oxalates, malonic acid, and malonates in PM2.5 could range from 7.6 to 68.0, 82.2 to 732.8, 6.3 to 150, and 1.3 to 60 ng m(-3), respectively. Because photooxidation properties and hygroscopicity of dicarboxylic acids can substantially differ from that of dicarboxylates, more studies are needed to quantify ambient oxalic acid and malonic acid vs oxalates and malonates.

  5. Association analysis for oxalate concentration in spinach

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Screening and breeding low-oxalate germplasm is a major objective in spinach breeding. This research aims to conduct association analysis and identify SNP markers associated with oxalate concentration in spinach germplasm. A total of 310 spinach genotypes including 300 USDA germplasm accessions and ...

  6. Fungal production of citric and oxalic acid: importance in metal speciation, physiology and biogeochemical processes.

    PubMed

    Gadd, G M

    1999-01-01

    The production of organic acids by fungi has profound implications for metal speciation, physiology and biogeochemical cycles. Biosynthesis of oxalic acid from glucose occurs by hydrolysis of oxaloacetate to oxalate and acetate catalysed by cytosolic oxaloacetase, whereas on citric acid, oxalate production occurs by means of glyoxylate oxidation. Citric acid is an intermediate in the tricarboxylic acid cycle, with metals greatly influencing biosynthesis: growth limiting concentrations of Mn, Fe and Zn are important for high yields. The metal-complexing properties of these organic acids assist both essential metal and anionic (e.g. phosphate) nutrition of fungi, other microbes and plants, and determine metal speciation and mobility in the environment, including transfer between terrestrial and aquatic habitats, biocorrosion and weathering. Metal solubilization processes are also of potential for metal recovery and reclamation from contaminated solid wastes, soils and low-grade ores. Such 'heterotrophic leaching' can occur by several mechanisms but organic acids occupy a central position in the overall process, supplying both protons and a metal-complexing organic acid anion. Most simple metal oxalates [except those of alkali metals, Fe(III) and Al] are sparingly soluble and precipitate as crystalline or amorphous solids. Calcium oxalate is the most important manifestation of this in the environment and, in a variety of crystalline structures, is ubiquitously associated with free-living, plant symbiotic and pathogenic fungi. The main forms are the monohydrate (whewellite) and the dihydrate (weddelite) and their formation is of significance in biomineralization, since they affect nutritional heterogeneity in soil, especially Ca, P, K and Al cycling. The formation of insoluble toxic metal oxalates, e.g. of Cu, may confer tolerance and ensure survival in contaminated environments. In semi-arid environments, calcium oxalate formation is important in the formation and

  7. Experimental demonstration of joule-level non-collinear optical parametric chirped-pulse amplification in yttrium calcium oxyborate.

    PubMed

    Yu, Lianghong; Liang, Xiaoyan; Li, Jinfeng; Wu, Anhua; Zheng, Yanqing; Lu, Xiaoming; Wang, Cheng; Leng, Yuxin; Xu, Jun; Li, Ruxin; Xu, Zhizhan

    2012-05-15

    In this Letter, we report on what is, to our knowledge, the first experimental demonstration of yttrium calcium oxyborate (YCOB) for joule-level and broadband non-collinear optical parametric chirped-pulse amplification centered at 800 nm. Based on a Ti:sapphire chirped-pulse amplification front end, an amplified signal energy of 3.36 J was generated with a pump of 35 J in the crystal. Compressed pulse duration of 44.3 fs, with a bandwidth of 49 nm, was achieved. The results confirm that YCOB crystal is another potential alternative as a final amplifier besides Ti:sapphire in a petawatt laser at 800 nm.

  8. Calcium and Potassium Channels in Experimental Subarachnoid Hemorrhage and Transient Global Ischemia

    PubMed Central

    Kamp, Marcel A.; Dibué, Maxine; Schneider, Toni; Steiger, Hans-Jakob; Hänggi, Daniel

    2012-01-01

    Healthy cerebrovascular myocytes express members of several different ion channel families which regulate resting membrane potential, vascular diameter, and vascular tone and are involved in cerebral autoregulation. In animal models, in response to subarachnoid blood, a dynamic transition of ion channel expression and function is initiated, with acute and long-term effects differing from each other. Initial hypoperfusion after exposure of cerebral vessels to oxyhemoglobin correlates with a suppression of voltage-gated potassium channel activity, whereas delayed cerebral vasospasm involves changes in other potassium channel and voltage-gated calcium channels expression and function. Furthermore, expression patterns and function of ion channels appear to differ between main and small peripheral vessels, which may be key in understanding mechanisms behind subarachnoid hemorrhage-induced vasospasm. Here, changes in calcium and potassium channel expression and function in animal models of subarachnoid hemorrhage and transient global ischemia are systematically reviewed and their clinical significance discussed. PMID:23251831

  9. Application of the optical method in experimental cardiology: action potential and intracellular calcium concentration measurement.

    PubMed

    Ronzhina, M; Cmiel, V; Janoušek, O; Kolářová, J; Nováková, M; Babula, P; Provazník, I

    2013-01-01

    It has been shown that, in addition to conventional contact electrode techniques, optical methods using fluorescent dyes can be successfully used for cardiac signal measurement. In this review, the physical and technical fundamentals of the method are described, as well as the properties of the most common systems for measuring action potentials and intracellular calcium concentration. Special attention is paid to summarizing limitations and trends in developing this method.

  10. Potential etiologic role of brushite in the formation of calcium (renal) stones

    NASA Astrophysics Data System (ADS)

    Pak, Charles Y. C.

    1981-05-01

    Brushite may play an important regulatory role in the formation of calcium -containing renal stones. The urinary environment from patients with hypercalciuric nephrolithiasis is typically supersaturated and shows an increased propensity for the spontaneous nucleation of brushite. Brushite has been identified in "stone-forming" urine and in stones. This crystalline phase may undergo phase transformation to hydroxyapatite or cause heterogeneous nucleation or epitaxial growth of calcium oxalate. Thus, brushite may also participate in the formation of stones of hydroxypatite or calcium oxalate.

  11. Effects of experimental osteoporosis and low calcium intake on postextraction sockets of rats

    PubMed Central

    d Prado, Renata F; Silveira, Vanessa Á S; d Rocha, Rosilene F; d Vasconcellos, Luana M R; Carvalho, Yasmin R

    2012-01-01

    Summary This study analysed the initial effects of the combination of oestrogen deficiency with a calcium-deficient diet on alveolar bone repair. Sixty-three 3-month-old female rats were either ovariectomized (OVX, n = 42) or sham-operated (SHAM, n = 21). Among the 42 ovariectomized rats, 21 received standard commercial food (OVX) and 21 received food with low calcium content (ESP). The mandibular first molars were extracted bilaterally 15 days after ovariectomy or sham surgery. The rats were weighed and killed at 7, 21 and 45 days after tooth extraction. The results were evaluated by descriptive microscopic analysis, histomorphometry of the trabecular and osteoid volume and mast cell counts. Analysis of the results indicated that trabecular volume and mast cell counts increased significantly over time, while osteoid volume decreased over time. Comparisons between the SHAM and OVX groups demonstrated no statistical differences, while comparison between the OVX and ESP groups indicated differences in trabecular volume and the number of mast cells. The data suggest that hormonal deficiency does not delay alveolar bone repair in OVX rats; however, oestrogen deficiency associated with calcium deficiency can lead to bone resorption through the activation of mast cells. PMID:22364763

  12. Cytoprotective and anti-apoptotic role of Terminalia arjuna on oxalate injured renal epithelial cells.

    PubMed

    Mittal, Amisha; Tandon, Simran; Singla, Surender Kumar; Tandon, Chanderdeep

    2017-02-08

    Urolithiasis is one of the painful multifactorial disorders caused by metabolic abnormalities influencing the composition of body fluids and urine. The bark of Terminalia arjuna (T. arjuna), very well known in Ayurveda for the treatment of cardiovascular diseases, possesses antioxidant and diuretic activity. The present study was undertaken to investigate the antiurolithiatic efficacy of aqueous extract of bark of T. arjuna on oxalate-induced injury to renal tubular epithelial cells. Madin-Darby canine kidney (MDCK) cells were exposed to 2 mM oxalate for 48 h to evaluate the protective effect of T. arjuna aqueous extract on cell viability, CaOx crystal adherence and apoptotic changes caused by oxalate. The results confirmed that oxalate injured MDCK cells were protected by T. arjuna extract. On treatment with a range concentrations, the cell viability increased in a concentration dependent manner. Moreover, the extract prevented the interaction of the calcium oxalate (CaOx) crystals with the cell surface and reduced the number of apoptotic cells. The current data suggests that T. arjuna bark confers a cytoprotective role and based on our results it could be a potential candidate from natural plant sources against urolithiasis.

  13. Experimental modelling of Calcium carbonate precipitation in the presence of phototrophic anaerobic bacteria Rhodovulum sp.

    NASA Astrophysics Data System (ADS)

    Bundeleva, Irina; Shirokova, Liudmila; Benezeth, Pascale; Pokrovsky, Oleg; Kompantseva, Elena

    2010-05-01

    -potential of the cells. To characterise the link between the rate of bacterial growth (biomass production) and the rate of CaCO3 precipitation, batch kinetic experiments were performed. These experiments were carried out in closed (anaerobic) bottles with initial concentration of calcium from 1 to 20 mM and from 5 to 20 mM bicarbonate. The biomass of cells, pH, [Ca2+] and [Alk] were measured as a function of time. Blank experiments (without cell or autoclaved cells) were always carried out. We found that the optimal conditions for both CaCO3 precipitation and biomass increase for the culture Rhodovulum sp. A-20s, is calcium concentration of 3 mM, whatever the concentration of bicarbonate (5, 10, 15 mM). Note also that for calcium concentration higher than 3 mM, the biomass production decreases. In the case of strictly anaerobic Rhodovulum sp. S-1765 bacteria, the optimal conditions for calcium carbonate precipitation is observed for the bicarbonate concentration of 10 mM, whatever the calcium concentration (3, 5, 10 mM). Overall, the present study allows quantitative modeling of bacterially-induced CaCO3 precipitation. It helps to distinguish between the effect of cell surface functional groups, surface electrical charge, soluble organic matter and metabolic change of solution pH on the rate and nature of precipitating calcium carbonate solid phase.

  14. Cardiac glycosides in the treatment of experimental overdose with calcium-blocking agents.

    PubMed

    Ramo, M P; Grupp, I; Pesola, M K; Heikkila, J; Luomanmaki, K; Schroder, T; Grupp, G

    1992-01-01

    The ability of digitalis compounds to counteract calcium antagonist overdose was studied in anesthetized dogs (n = 6, 13.5 +/- 0.7 kg) and isolated trabeculae from human hearts (n = 7). Digitalis caused by increasing intracellular cytosolic Ca2+ concentration through Na+/Ca(2+)-exchange across the cell membrane, was postulated to overcome the detrimental effects of excessive slow calcium-channel blockade. In anesthetized dogs, an infusion of verapamil (40 mg/30 min, i.v.) decreased mean arterial pressure from 88 +/- 6 to 66 +/- 6 mm Hg (P < 0.05), reduced systemic vascular resistance (SVR) from 3838 +/- 916 to 2200 +/- 669 dyne.s/cm5 (P < 0.05), and induced total atrio-ventricular (A-V) block in three animals. Stroke volume (SV) remained unchanged. Administration (i.v.) of NaCl (0.9%, 200 ml) and calcium gluconate (100 mg)--to increase the availability of Na+ and Ca(2+)--together with atropine (0.2 mg)--to block the parasympathetic effects of digoxin on A-V conduction--increased left ventricular contractility (15%) but had no significant effects on blood pressure, SV, or A-V block. Digoxin (0.125 mg) returned sinus rhythm in all dogs and, by increasing SVR (P < 0.05) and left ventricular contractility (P < 0.05), returned arterial pressures to baseline. Because of increased afterload, SV decreased slightly (15%) despite increased cardiac contractility. In experiments with isolated trabeculae from diseased human hearts, TA 3090 (Clentiazem) depressed contractile force and ouabain, another glycoside, restored contractile force within 30 min.(ABSTRACT TRUNCATED AT 250 WORDS)

  15. Oxalate metabolism in magnesium-deficient rats.

    PubMed

    Rattan, V; Thind, S K; Jethi, R K; Sidhu, H; Nath, R

    1993-06-01

    Male weanling rats were maintained on magnesium-deficient diet for 30 d and compared with pair-fed control rats fed magnesium-supplemented diet. Magnesium deficiency led to slow growth and finally to a significant decrease in body weight (P < 0.001) accompanied by a significant hypomagnesaemia, hypomagnesuria and hyperoxaluria (P < 0.001 in each case) in experimental rats as compared to the control rats. Magnesium deficiency altered the glyoxylate metabolism in the liver and kidney mitochondria by significantly decreasing glyoxylate oxidation (by 26 per cent in liver and 17 per cent in kidney) and activity of alpha-ketoglutarate:glyoxylate carboligase enzyme (by 35 per cent in liver and 27 per cent in kidney) in the experimental animals. A significant increase in the specific activities of glycolic acid oxidase (P < 0.001) and glycolic acid dehydrogenase (P < 0.01) and a significant decrease in alanine transaminase (P < 0.01) was also observed in magnesium-deficient rats. No change in liver and kidney lactate dehydrogenase was observed. Thus magnesium deficiency in rats leads to accumulation of glyoxylate in the tissues, a part of which is converted into oxalate, thereby promoting hyperoxaluria.

  16. CONCENTRATION OF Pu USING OXALATE TYPE CARRIER

    DOEpatents

    Ritter, D.M.; Black, R.P.S.

    1960-04-19

    A method is given for dissolving and reprecipitating an oxalate carrier precipitate in a carrier precipitation process for separating and recovering plutonium from an aqueous solution. Uranous oxalate, together with plutonium being carried thereby, is dissolved in an aqueous alkaline solution. Suitable alkaline reagents are the carbonates and oxulates of the alkali metals and ammonium. An oxidizing agent selected from hydroxylamine and hydrogen peroxide is then added to the alkaline solution, thereby oxidizing uranium to the hexavalent state. The resulting solution is then acidified and a source of uranous ions provided in the acidified solution, thereby forming a second plutoniumcarrying uranous oxalate precipitate.

  17. Diet and calcium stones.

    PubMed Central

    Hughes, J; Norman, R W

    1992-01-01

    OBJECTIVE: To review the current literature on the dietary modification of urinary risk factors as a means of reducing the likelihood of recurrent stone formation and to develop practical dietary recommendations that might be useful to this end. DATA SOURCES: MEDLINE was searched for English-language articles published from 1983 to 1990. Additional references were selected from the bibliographies of identified articles. STUDY SELECTION: Nonrandomized trials and retrospective reviews were included because of a paucity of randomized controlled trials. DATA SYNTHESIS: Information on the dietary intake of calcium, oxalate, protein, sodium and fibre and on alcohol and fluid intake was used to develop practical guidelines on dietary modification. CONCLUSION: Dietary modification plays an important role in the reduction of urinary risk factors in patients with calcium stone disease of the urinary tract. As an initial form of prevention attention should be directed toward moderating the intake of calcium, oxalate, protein, sodium and alcohol and increasing the intake of fibre and water. Future research should include an assessment of the long-term reduction of dietary and urinary risk factors and the rates of recurrence of calcium stones. PMID:1310430

  18. Urinary excretion of orally administered oxalic acid in saccharin and o-phenylphenol-fed NMRI mice.

    PubMed

    Salminen, E; Salminen, S

    1986-01-01

    Both saccharin and o-phenylphenol have been suggested to be carcinogenic to the urinary bladder in experimental animals, but the mechanism has remained unclear. The aim of this study was to investigate the effects of dietary saccharin and o-phenylphenol on the urinary excretion of dietary oxalic acid. Male NMRI mice were gradually adapted to either 3% o-phenylphenol or 5% saccharin in their diet. Having being adapted to these diets for 1 week or after consuming them for 3 months, the animals were fasted for 6 h and given a 2.5-microCi oral dose of U-14C-oxalic acid. Dosed animals were kept in metabolism cages for 48 h to monitor urinary and fecal excretion of the label. Adaptation to dietary o-phenylphenol appeared to increase the urinary excretion of orally administered U-14C-oxalic acid when food and water were available during urinary and fecal collections. Adaptation to dietary saccharin had little effect on urinary oxalate levels when compared to control animals. These results indicate that changes in urinary oxalate levels should be more carefully studied in connection with potential urinary bladder carcinogens to avoid the possibility of bladder irritation by increased urinary oxalate excretion.

  19. Artificial photosynthesis of oxalate and oxalate-based polymer by a photovoltaic reactor

    NASA Astrophysics Data System (ADS)

    Nong, Guangzai; Chen, Shan; Xu, Yuanjin; Huang, Lijie; Zou, Qingsong; Li, Shiqiang; Mo, Haitao; Zhu, Pingchuan; Cen, Weijian; Wang, Shuangfei

    2014-01-01

    A photovoltaic reactor was designed for artificial photosynthesis, based on the reactions involved in high energy hydrogen atoms, which were produced from water electrolysis. Water and CO2, under the conditions studied, were converted to oxalate (H2C2O4) and a polymer. This was the first time that the oxalates and oxalate-based polymer were produced from the artificial photosynthesis process.

  20. Artificial photosynthesis of oxalate and oxalate-based polymer by a photovoltaic reactor.

    PubMed

    Nong, Guangzai; Chen, Shan; Xu, Yuanjin; Huang, Lijie; Zou, Qingsong; Li, Shiqiang; Mo, Haitao; Zhu, Pingchuan; Cen, Weijian; Wang, Shuangfei

    2014-01-06

    A photovoltaic reactor was designed for artificial photosynthesis, based on the reactions involved in high energy hydrogen atoms, which were produced from water electrolysis. Water and CO2, under the conditions studied, were converted to oxalate (H2C2O4) and a polymer. This was the first time that the oxalates and oxalate-based polymer were produced from the artificial photosynthesis process.

  1. Artificial photosynthesis of oxalate and oxalate-based polymer by a photovoltaic reactor

    PubMed Central

    Nong, Guangzai; Chen, Shan; Xu, Yuanjin; Huang, Lijie; Zou, Qingsong; Li, Shiqiang; Mo, Haitao; Zhu, Pingchuan; Cen, Weijian; Wang, Shuangfei

    2014-01-01

    A photovoltaic reactor was designed for artificial photosynthesis, based on the reactions involved in high energy hydrogen atoms, which were produced from water electrolysis. Water and CO2, under the conditions studied, were converted to oxalate (H2C2O4) and a polymer. This was the first time that the oxalates and oxalate-based polymer were produced from the artificial photosynthesis process. PMID:24389750

  2. Metabolic Conversion of l-Ascorbic Acid to Oxalic Acid in Oxalate-accumulating Plants.

    PubMed

    Yang, J C; Loewus, F A

    1975-08-01

    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.

  3. Metabolic Conversion of l-Ascorbic Acid to Oxalic Acid in Oxalate-accumulating Plants 1

    PubMed Central

    Yang, Joan C.; Loewus, Frank A.

    1975-01-01

    l-Ascorbic acid-1-14C 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. PMID:16659288

  4. The relationship between colonization of Oxalobacter formigenes serum oxalic acid and endothelial dysfunction in hemodialysis patients: from impaired colon to impaired endothelium.

    PubMed

    Turkmen, K; Erdur, F M

    2015-03-01

    Cardiovascular disease (CVD) remains the leading cause of morbidity and mortality in chronic kidney disease (CKD) patients receiving hemodialysis (HD). Oxalic acid is a uremic retention molecule that has been extensively studied in the pathogenesis of calcium-oxalate stones. Oxalobacter formigenes (O. formigenes), a component of the colonic microbiota, plays an important role in oxalate homeostasis. Little is known regarding the colonization of HD patients by O. formigenes and the exact role of this bacterial species in oxalic acid metabolism in these patients. We hypothesized that oxalic acid may be insufficiently degraded in HD patients due to under colonization of the colon by O. formigenes in these patients. To test this hypothesis, we sought to quantitatively measure fecal O. formigenes levels and serum oxalic acid levels in HD patients. We also suggest that increased oxalic acid levels may be associated with endothelial dysfunction and aortic stiffness, both of which are commonly observed in HD patients. Increased colonization with O. formigenes via the ingestion of prebiotics and probiotics could potentially decrease serum oxalic acid levels and improve cardiovascular outcomes in HD patients.

  5. Chaga mushroom-induced oxalate nephropathy.

    PubMed

    Kikuchi, Yuko; Seta, Koichi; Ogawa, Yayoi; Takayama, Tatsuya; Nagata, Masao; Taguchi, Takashi; Yahata, Kensei

    2014-06-01

    Chaga mushrooms have been used in folk and botanical medicine as a remedy for cancer, gastritis, ulcers, and tuberculosis of the bones. A 72-year-old Japanese female had been diagnosed with liver cancer 1 year prior to presenting at our department. She underwent hepatectomy of the left lobe 3 months later. Chaga mushroom powder (4 - 5 teaspoons per day) had been ingested for the past 6 months for liver cancer. Renal function decreased and hemodialysis was initiated. Renal biopsy specimens showed diffuse tubular atrophy and interstitial fibrosis. Oxalate crystals were detected in the tubular lumina and urinary sediment and oxalate nephropathy was diagnosed. Chaga mushrooms contain extremely high oxalate concentrations. This is the first report of a case of oxalate nephropathy associated with ingestion of Chaga mushrooms.

  6. Chemical modification of oxalate decarboxylase to improve adsorption capacity.

    PubMed

    Lin, Rihui; He, Junbin; Wu, Jia; Cai, Xinghua; Long, Han; Chen, Shengfeng; Liu, Haiqian

    2017-02-03

    In order to enhance the adsorption capacity of oxalate decarboxylase (Oxdc) on calcium oxalate monohydrate crystals and improve the application performance of Oxdc, chemical modification of Oxdc with ethylenediaminetetraacetic dianhydride (EDTAD) was investigated in this work. The sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and liquid chromatography tandem mass spectrometry (LC/MS) analysis results demonstrated that Oxdc and EDTAD have been covalently bound, and suggested that the chemical modification occurred at the free amino of the side chain and the α-amine of the N-terminus of Oxdc. Fluorescene and circular dichroic measurement showed that the structure and conformation of Oxdc were tinily altered after modification by EDTAD. The optimum pH of EDTAD-modified Oxdc was shifted to the alkaline side about 1.5 unit and it has a higher thermostability. The analysis of kinetic parameters indicated that the EDTAD-modified Oxdc showed a higher affinity towards the substrate. Through modification the adsorption capacity of Oxdc onto CaOx monohydrate crystals was increased by 42.42%.

  7. Acute oxalate nephropathy following kidney transplantation: Report of three cases

    PubMed Central

    Taheri, Diana; Gheissari, Alaleh; Shaabani, Pooria; Tabibian, Seyed Reza; Mortazavi, Mojgan; Seirafian, Shiva; Merrikhi, Alireza; Fesharakizadeh, Mehdi; Dolatkhah, Shahaboddin

    2015-01-01

    Calcium oxalate (CaOx) crystal deposition is a common finding immediately after kidney transplantation. However, small depositions of CaOx could be benign while extensive depositions lead to poor graft outcome. Here we report three cases with end-stage renal disease (ESRD), bilateral nephrolithiasis, and unknown diagnosis of primary hyperoxaluria (PH) who underwent a renal transplant and experienced an early-onset graft failure. Although an acute rejection was suspected, renal allograft biopsies and subsequent allograft nephrectomies showed extensive CaOx deposition, which raised a suspicion of PH. Even though increased urinary excretion of CaOx was found in all patients, this diagnosis could be confirmed with further tests including genetic study and metabolic assay. In conclusion, massive CaOx deposition in kidney allograft is an important cause of poor allograft survival and needs special management. Furthermore, our cases suggest patients with ESRD and a history of nephrolithiasis should be screened for elevated urinary oxalate excretion and rule out of PH. PMID:26664431

  8. Oxalate Blockage of Calcium and Iron: A Student Learning Activity.

    ERIC Educational Resources Information Center

    Walker, Noojin

    1988-01-01

    Describes a student learning activity used to teach the meaning of percentage composition, mole concept, selective precipitation, and limiting factors. Presents two word problems and their solutions. (CW)

  9. Evaluation of Antibiotic-loaded Calcium Phosphate Bone Cement in a Cranium-infected Experimental Model

    PubMed Central

    SAKAMOTO, Yoshiaki; OCHIAI, Hiroko; OHSUGI, Ikuko; INOUE, Yoshikazu; YOSHIMURA, Yoko; KISHI, Kazuo

    2014-01-01

    Treatment of calvarial defects has remained a challenge in reconstruction surgery, especially because of infection at these sites. We produced a bactericidal biomaterial for treating infected bone defects by using calcium phosphate bone cement mixed with antibiotics. We evaluated the usefulness of this material mixed with the antibiotic vancomycin in a cranium-infected rat model. The concentration of vancomycin used was 5.0 wt%, as reported in our previous study. In order to establish the rat model, a cranium defect (diameter, 5 mm) was made that was infected with methicillin-resistant Staphylococcus aureus (MRSA). Thirty-six rats were divided into 6 groups depending on whether an autologous graft or bone cement with or without antibiotic was used for the defect. After 1 and 4 weeks, abscess formation was checked, tissue bacterial counts were determined, and pathological examination was performed. At both 1 and 4 weeks, no MRSA was detected on tissue bacterial culture or pathological examination in groups that received bone cement with antibiotics. In groups that received bone cement without antibiotic, MRSA was detected, and the bone cement had compromised and disintegrated into several slices. In conclusion, bone cement that contains antibiotics appears to be effective not only for reconstruction in cases of cranial defect, but also in terms of preventing infection. PMID:24670313

  10. Treatment of calcium nephrolithiasis in the patient with hyperuricosuria.

    PubMed

    Arowojolu, Omotayo; Goldfarb, David S

    2014-12-01

    Nearly one-third of patients with calcium stones have hyperuricosuria. In vitro studies and clinical trials have investigated the relationship between uric acid and calcium stones, but the association between hyperuricosuria and calcium stone formation in patients is still being debated. Uric acid appears to cause salting out of calcium oxalate in human urine. However, the importance of this in vitro phenomenon to the proposed association is not supported in cross-sectional observational studies. A small placebo-controlled randomized clinical trial showed that allopurinol decreased the rate of recurrent calcium oxalate calculi in patients with hyperuricosuria and normocalciuria. An assessment of the effect of combination therapy of allopurinol with indapamide showed no additive effect. Allopurinol may have antioxidant effects that are responsible for its reducing calcium stone formation, which are independent of xanthine oxidase inhibition. In addition, a newer xanthine oxidoreductase inhibitor, febuxostat, may also be effective in the prevention of calcium stones, as it reduces urinary uric acid excretion.

  11. REMOVING SLUDGE HEELS FROM SAVANNAH RIVER SITE WASTE TANKS BY OXALIC ACID DISSOLUTION

    SciTech Connect

    Poirier, M; David Herman, D; Fernando Fondeur, F; John Pareizs, J; Michael Hay, M; Bruce Wiersma, B; Kim Crapse, K; Thomas Peters, T; Samuel Fink, S; Donald Thaxton, D

    2009-03-01

    The Savannah River Site (SRS) will remove sludge as part of waste tank closure operations. Typically the bulk sludge is removed by mixing it with supernate to produce a slurry, and transporting the slurry to a downstream tank for processing. Experience shows that a residual heel may remain in the tank that cannot be removed by this conventional technique. In the past, SRS used oxalic acid solutions to disperse or dissolve the sludge heel to complete the waste removal. To better understand the actual conditions of oxalic acid cleaning of waste from carbon steel tanks, the authors developed and conducted an experimental program to determine its effectiveness in dissolving sludge, the hydrogen generation rate, the generation rate of other gases, the carbon steel corrosion rate, the impact of mixing on chemical cleaning, the impact of temperature, and the types of precipitates formed during the neutralization process. The test samples included actual SRS sludge and simulated SRS sludge. The authors performed the simulated waste tests at 25, 50, and 75 C by adding 8 wt % oxalic acid to the sludge over seven days. They conducted the actual waste tests at 50 and 75 C by adding 8 wt % oxalic acid to the sludge as a single batch. Following the testing, SRS conducted chemical cleaning with oxalic acid in two waste tanks. In Tank 5F, the oxalic acid (8 wt %) addition occurred over seven days, followed by inhibited water to ensure the tank contained enough liquid to operate the mixer pumps. The tank temperature during oxalic acid addition and dissolution was approximately 45 C. The authors analyzed samples from the chemical cleaning process and compared it with test data. The conclusions from the work are: (1) Oxalic acid addition proved effective in dissolving sludge heels in the simulant demonstration, the actual waste demonstration, and in SRS Tank 5F. (2) The oxalic acid dissolved {approx} 100% of the uranium, {approx} 100% of the iron, and {approx} 40% of the manganese

  12. Probiotics and Other Key Determinants of Dietary Oxalate Absorption1

    PubMed Central

    Liebman, Michael; Al-Wahsh, Ismail A.

    2011-01-01

    Oxalate is a common component of many foods of plant origin, including nuts, fruits, vegetables, grains, and legumes, and is typically present as a salt of oxalic acid. Because virtually all absorbed oxalic acid is excreted in the urine and hyperoxaluria is known to be a considerable risk factor for urolithiasis, it is important to understand the factors that have the potential to alter the efficiency of oxalate absorption. Oxalate bioavailability, a term that has been used to refer to that portion of food-derived oxalate that is absorbed from the gastrointestinal tract (GIT), is estimated to range from 2 to 15% for different foods. Oxalate bioavailability appears to be decreased by concomitant food ingestion due to interactions between oxalate and coingested food components that likely result in less oxalic acid remaining in a soluble form. There is a lack of consensus in the literature as to whether efficiency of oxalate absorption is dependent on the proportion of total dietary oxalate that is in a soluble form. However, studies that directly compared foods of varying soluble oxalate contents have generally supported the proposition that the amount of soluble oxalate in food is an important determinant of oxalate bioavailability. Oxalate degradation by oxalate-degrading bacteria within the GIT is another key factor that could affect oxalate absorption and degree of oxaluria. Studies that have assessed the efficacy of oral ingestion of probiotics that provide bacteria with oxalate-degrading capacity have led to promising but generally mixed results, and this remains a fertile area for future studies. PMID:22332057

  13. Response to Dietary Oxalate after Bariatric Surgery

    PubMed Central

    Froeder, Leila; Arasaki, Carlos Haruo; Malheiros, Carlos Alberto; Baxmann, Alessandra Calábria

    2012-01-01

    Summary Background and objectives Bariatric surgery (BS) may be associated with increased oxalate excretion and a higher risk of nephrolithiasis. This study aimed to investigate urinary abnormalities and responses to an acute oxalate load as an indirect assessment of the intestinal absorption of oxalate in this population. Design, setting, participants, & measurements Twenty-four–hour urine specimens were collected from 61 patients a median of 48 months after BS (post-BS) as well as from 30 morbidly obese (MO) participants; dietary information was obtained through 24-hour food recalls. An oral oxalate load test (OLT), consisting of 2-hour urine samples after overnight fasting and 2, 4, and 6 hours after consuming 375 mg of oxalate (spinach juice), was performed on 21 MO and 22 post-BS patients 12 months after BS. Ten post-BS patients also underwent OLT before surgery (pre-BS). Results There was a higher percentage of low urinary volume (<1.5 L/d) in post-BS versus MO (P<0.001). Hypocitraturia and hyperoxaluria (P=0.13 and P=0.36, respectively) were more frequent in BS versus MO patients. The OLT showed intragroup (P<0.001 for all periods versus baseline) and intergroup differences (P<0.001 for post-BS versus MO; P=0.03for post-BS versus pre-BS). The total mean increment in oxaluria after 6 hours of load, expressed as area under the curve, was higher in both post-BS versus MO and in post-BS versus pre-BS participants (P<0.001 for both). Conclusions The mean oxaluric response to an oxalate load is markedly elevated in post-bariatric surgery patients, suggesting that increased intestinal absorption of dietary oxalate is a predisposing mechanism for enteric hyperoxaluria. PMID:23024163

  14. Improvement of the chromatographic separation of several 1,4-dihydropyridines calcium channel antagonist drugs by experimental design.

    PubMed

    Baranda, Ana B; Etxebarria, Nestor; Jiménez, Rosa M; Alonso, Rosa M

    2005-01-01

    A high-performance liquid chromatographic method with diode array detection has been developed and optimized for the separation of five calcium channel blockers belonging to the 1,4-dihydropyridine subgroup (nifedipine and related drugs). The possibility of the simultaneous drug analysis allows a decrease of time during the assay as well as a saving of reagents and solvents. In this work, the effect of four experimental parameters (organic modifier percentage, pH value, concentration of the buffer in the mobile phase, and column temperature) on the chromatographic resolution are investigated by experimental design in order to optimize the chromatographic separation of five 1,4-dihydropyridines (amlodipine, nitrendipine, felodipine, lacidipine, and lercanidipine). Fractional factorial design, central composite design, and finally the Multisimplex program are used to establish the optimal conditions in terms of resolution and minimum analysis time. Optimal separation of the five compounds under study is achieved in less than 12 min using a Sulpecosil LC-ABZ+Plus C18 column, a composition of mobile phase of acetonitrile-10mM acetic acid acetate buffer pH 5 (72:28, v/v) at a flow rate of 1 mL/min, a column temperature of 30 degrees C +/- 0.1 degrees C, and a detection wavelength of 238 nm.

  15. ADVANCED OXIDATION: OXALATE DECOMPOSITION TESTING WITH OZONE

    SciTech Connect

    Ketusky, E.; Subramanian, K.

    2012-02-29

    At the Savannah River Site (SRS), oxalic acid is currently considered the preferred agent for chemically cleaning the large underground Liquid Radioactive Waste Tanks. It is applied only in the final stages of emptying a tank when generally less than 5,000 kg of waste solids remain, and slurrying based removal methods are no-longer effective. The use of oxalic acid is preferred because of its combined dissolution and chelating properties, as well as the fact that corrosion to the carbon steel tank walls can be controlled. Although oxalic acid is the preferred agent, there are significant potential downstream impacts. Impacts include: (1) Degraded evaporator operation; (2) Resultant oxalate precipitates taking away critically needed operating volume; and (3) Eventual creation of significant volumes of additional feed to salt processing. As an alternative to dealing with the downstream impacts, oxalate decomposition using variations of ozone based Advanced Oxidation Process (AOP) were investigated. In general AOPs use ozone or peroxide and a catalyst to create hydroxyl radicals. Hydroxyl radicals have among the highest oxidation potentials, and are commonly used to decompose organics. Although oxalate is considered among the most difficult organic to decompose, the ability of hydroxyl radicals to decompose oxalate is considered to be well demonstrated. In addition, as AOPs are considered to be 'green' their use enables any net chemical additions to the waste to be minimized. In order to test the ability to decompose the oxalate and determine the decomposition rates, a test rig was designed, where 10 vol% ozone would be educted into a spent oxalic acid decomposition loop, with the loop maintained at 70 C and recirculated at 40L/min. Each of the spent oxalic acid streams would be created from three oxalic acid strikes of an F-area simulant (i.e., Purex = high Fe/Al concentration) and H-area simulant (i.e., H area modified Purex = high Al/Fe concentration) after nearing

  16. Global impacts of multiphase oxalate production

    NASA Astrophysics Data System (ADS)

    Tost, Holger; Taraborrelli, Domenico

    2013-04-01

    Fine mode atmospheric aerosols are dominated by the organic fraction. A large fraction of these organic compounds consists of oxalates and carboxylic acids. Some of these compounds are produced in the gas phase and then subsequently partition into aerosol particles whereas others are produced directly in the aqueous phase in either cloud droplets or deliquesced aerosol particles. In this study we investigate the contribution of oxalates to the global organic aerosol burden using a comprehensive atmospheric chemistry general circulation model including explicit multiphase chemistry schemes for clouds and aerosols. For that purpose the aqueous phase chemistry has been augmented by a mechanism for oxalates, combined with a consistent gas phase chemistry of corresponding oxidation products from isoprene degradation. Using these tools we will present an analysis of both budget and transport estimates which provide indications for the climate impact of these compounds.

  17. The adsorption and photo-degradation of oxalic acid at the TiO2 surface.

    NASA Astrophysics Data System (ADS)

    Mendive, Cecilia; Blesa, Miguel; Bahnemann, Detlef

    2006-03-01

    Oxalic acid is the simplest model compound to study the heterogeneous photocatalytic oxidation of pollutants on TiO2 containing more than one carboxylate group. We have carried out a study of a system of an oxalic acid solution in contact with a thin film of TiO2 particles employing ATR - FTIR in combination with quantum chemical calculations. Thus, possible adsorption structures have been identified and molecular dynamic simulations have been used to compare their predictions with the experimental data. It was found that the adsorption of oxalic acid on TiO2 in the dark can be explained in terms of two surface complexation modes for the anatase phase and only one surface complexation mode for the rutile phase. We have found that under illumination one of the complexes on the anatase phase preferably undergoes photo-degradation. At the same time water molecules are desorbed from the TiO2 surface by a thermal mechanism induced by the absorption of photons. Both processes favor the adsorption of more molecules of oxalic acid at the TiO2 surface which is thus enriched in the second complexation mode. A similar mechanism was found to occur on the rutile phase. The only complexation mode appears not to be photo-sensitive but the TiO2 surface is enriched in oxalic acid under illumination due to the replacement of photo-desorbed water molecules.

  18. Tungsten carbide nanotubes supported platinum nanoparticles as a potential sensing platform for oxalic acid.

    PubMed

    Maiyalagan, Thandavarayan; Kannan, Palanisamy; Jönsson-Niedziolka, Martin; Niedziolka-Jönsson, Joanna

    2014-08-05

    Supported tungsten carbide is an efficient and vital nanomaterial for the development of high-performance, sensitive, and selective electrochemical sensors. In this work, tungsten carbide with tube-like nanostructures (WC NTs) supported platinum nanoparticles (PtNPs) are synthesized and explored as an efficient catalyst toward electrochemical oxidation of oxalic acid for the first the time. The WC NTs supported PtNPs modified glassy carbon (GC) electrode is highly sensitive toward the electrochemical oxidation of oxalic acid. A large decrease in the oxidation overpotential (220 mV) and significant enhancement in the peak current compared to unmodified and Pt/C modified GC electrodes have been observed without using any redox mediator. Moreover, WC NTs supported PtNPs modified electrode possessed wide linear concentration ranges from 0 to 125 nM and a higher sensitivity toward the oxidation of oxalic acid (80 nA/nM) achieved by the amperometry method. The present modified electrode showed an experimentally determined lowest detection limit (LOD) of 12 nM (S/N = 3). Further, WC NTs supported PtNPs electrode can be demonstrated to have an excellent selectivity toward the detection of oxalic acid in the presence of a 200-fold excess of major important interferents. The practical application of WC NTs supported PtNPs has also been demonstrated in the detection of oxalic acid in tomato fruit sample, by differential pulse voltammetry under optimized conditions.

  19. Physical simulation of precipitation of radioactive element oxalates by using the harmless neodymium oxalate for studying the agglomeration phenomena

    NASA Astrophysics Data System (ADS)

    Lalleman, Sophie; Bertrand, Murielle; Plasari, Edouard

    2012-03-01

    Oxalic precipitation is usually applied in nuclear industry to process radioactive wastes or to recover actinides from a multicomponent solution. This paper deals with the development of methods adapted to a nuclear environment in order to study the agglomeration phenomena during actinide oxalic precipitation. These methods are previously setup with harmless elements that simulate the actinide behaviour: the lanthanides. A parametric study is carried out to quantify the influence of operating parameters on the agglomeration kernel and to determine a kinetic law for this mechanism. The experimental study is performed in a continuous-MSMPR precipitator at steady-state. The method is based on the resolution of two population balances using the moment approach, one for elementary crystals and the other for agglomerates. Provided that the kinetic rates of nucleation and growth are known, the agglomeration kernel can be obtained from a mathematical treatment of the experimental particle size distributions. Results point out that experimental crystal sizes are consistent with an independent kernel. It appears that the agglomeration kernel is directly proportional to supersaturation, increases with temperature but is limited by ionic strength and shear rate.

  20. Calcium supplements

    MedlinePlus

    ... TYPES OF CALCIUM SUPPLEMENTS Forms of calcium include: Calcium carbonate: Over-the-counter (OTC) antacid products, such as Tums and Rolaids, contain calcium carbonate. These sources of calcium do not cost much. ...

  1. 40 CFR 721.10628 - Mixed metal oxalate (generic).

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Mixed metal oxalate (generic). 721... Substances § 721.10628 Mixed metal oxalate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as mixed metal oxalate (PMN...

  2. 40 CFR 721.10628 - Mixed metal oxalate (generic).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Mixed metal oxalate (generic). 721... Substances § 721.10628 Mixed metal oxalate (generic). (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified generically as mixed metal oxalate (PMN...

  3. Experimental and theoretical study of molecular structure of beryllium, magnesium, calcium, strontium and barium 4-nitrobenzoates.

    PubMed

    Samsonowicz, M; Regulska, E; Świsłocka, R; Lewandowski, W

    2013-02-15

    The influence of alkaline earth metal ions on the electronic system of 4-nitrobenzoic acid was studied in this paper. The vibrational (FT-IR) and NMR ((1)H and (13)C) spectra were recorded for 4-nitrobenzoic acid (4-nba) and its salts (4-nb). The assignment of vibrational spectra was done. Some shifts of band wavenumbers in alkaline earth metal 4-nitrobenzoates spectra were observed in the series from magnesium to barium salts. Good correlations between wavenumbers of the vibrational bands in the IR spectra of studied salts and ionic potential, electronegativity, inverse of atomic mass, ionic radius and ionization energy of studied metals were found. The regular changes in the chemical shifts of protons ((1)H NMR) and carbons ((13)C NMR) in the series of studied salts were also observed. Optimized geometrical structures of studied compounds were calculated by B3LYP method using 6-311++G(**) as well as LANL2DZ basis sets. Theoretical wavenumbers and intensities in IR and chemical shifts in NMR spectra were also obtained. The calculated parameters were compared with experimental data of studied compounds.

  4. Calcium and Mitosis

    NASA Technical Reports Server (NTRS)

    Hepler, P.

    1983-01-01

    Although the mechanism of calcium regulation is not understood, there is evidence that calcium plays a role in mitosis. Experiments conducted show that: (1) the spindle apparatus contains a highly developed membrane system that has many characteristics of sarcoplasmic reticulum of muscle; (2) this membrane system contains calcium; and (3) there are ionic fluxes occurring during mitosis which can be seen by a variety of fluorescence probes. Whether the process of mitosis can be modulated by experimentally modulating calcium is discussed.

  5. Comparison of the hemostatic effects of oxidized cellulose and calcium alginate in an experimental animal model of hepatic parenchymal bleeding

    PubMed Central

    Dorterler, Mustafa Erman; Ayangil, Harun Resit; Turan, Cüneyt; Deniz, Kemal

    2016-01-01

    Background: Despite all recent developments, bleeding is still one of the main causes of increasing morbidity and mortality following both trauma and elective hepatic surgery. The main goal of treatment is stop the bleeding immediately. In this study, the hemostatic and histopathological effects of Ankaferd blood stopper (ABS), oxidized cellulose (OC), and calcium alginate (CA) were compared in an experimental liver injury. Materials and Methods: Forty Wistar albino rats were randomly divided into four groups of ten animals each, receiving 0.9% NaCl, CA, OC, or ABS following liver resection. After 5 days, the samples from the resection site were acquired for histopathological evaluation. The efficacy of the agents was assessed using the hematocrit level and histopathological examination. Statistical analyses were applied. Results: The amount of bleeding was lowest in ABS–treated rats, followed by those treated with OC, CA, and NaCl, respectively. The difference among the groups was statistically significant (P < 0.001). ABS–treated rats also had significantly less necrosis than those receiving OC; other differences in this regard were not significant. Inflammatory status was significantly different between OC- and CA–treated rats (P < 0.05) but not among the other groups (P > 0.05). No significant difference was determined between the groups regarding granulation (P > 0.05). Conclusion: ABS reduced the volume of bleeding in liver surgery and partial liver resection. The hemostatic effect of CA was limited. PMID:28149820

  6. The Relationship between Serum Oxalic Acid, Central Hemodynamic Parameters and Colonization by Oxalobacter formigenes in Hemodialysis Patients

    PubMed Central

    Gulhan, Baris; Turkmen, Kultigin; Aydin, Merve; Gunay, Murat; Cıkman, Aytekin; Kara, Murat

    2015-01-01

    Background/Objective Elevated pulse wave velocity (PWV) and central aortic blood pressures are independent predictors of increased cardiovascular morbidity and mortality in hemodialysis (HD) patients. Oxalic acid is a uremic retention molecule that is extensively studied in the pathogenesis of calcium oxalate stones. Oxalobacter formigenes, a member of the colon microbiota, has important roles in oxalate homeostasis. Data regarding the colonization by and the exact role of O. formigenes in the pathogenesis of oxalic acid metabolism in HD patients are scant. Hence, we aimed to determine the relationship between fecal O. formigenes colonization, serum oxalic acid and hemodynamic parameters in HD patients with regard to the colo-reno-cardiac axis. Methods Fifty HD patients were enrolled in this study. PWV and central aortic systolic (cASBP) and diastolic blood pressures (cADBP) were measured with a Mobil-O-Graph (I.E.M. GmbH, Stolberg, Germany). Serum oxalic acid levels were assessed by ELISA, and fecal O. formigenes DNA levels were isolated and measured by real-time PCR. Results Isolation of fecal O. formigenes was found in only 2 HD patients. One of them had 113,609 copies/ml, the other one had 1,056 copies/ml. Serum oxalic acid levels were found to be positively correlated with PWV (r = 0.29, p = 0.03), cASBP (r = 0.33, p = 0.001) and cADBP (r = 0.42, p = 0.002) and negatively correlated with LDL (r = −0.30, p = 0.03). In multivariate linear regression analysis, PWV was independently predicted by oxalic acid, glucose and triglyceride. Conclusions This is the first study that demonstrates the absence of O. formigenes as well as a relation between serum oxalic acid and cASBP, cADBP and PWV in HD patients. Replacement of O. formigenes with pre- and probiotics might decrease serum oxalic acid levels and improve cardiovascular outcomes in HD patients. PMID:26195968

  7. An Investigational RNAi Therapeutic Targeting Glycolate Oxidase Reduces Oxalate Production in Models of Primary Hyperoxaluria.

    PubMed

    Liebow, Abigail; Li, Xingsheng; Racie, Timothy; Hettinger, Julia; Bettencourt, Brian R; Najafian, Nader; Haslett, Patrick; Fitzgerald, Kevin; Holmes, Ross P; Erbe, David; Querbes, William; Knight, John

    2017-02-01

    Primary hyperoxaluria type 1 (PH1), an inherited rare disease of glyoxylate metabolism, arises from mutations in the enzyme alanine-glyoxylate aminotransferase. The resulting deficiency in this enzyme leads to abnormally high oxalate production resulting in calcium oxalate crystal formation and deposition in the kidney and many other tissues, with systemic oxalosis and ESRD being a common outcome. Although a small subset of patients manages the disease with vitamin B6 treatments, the only effective treatment for most is a combined liver-kidney transplant, which requires life-long immune suppression and carries significant mortality risk. In this report, we discuss the development of ALN-GO1, an investigational RNA interference (RNAi) therapeutic targeting glycolate oxidase, to deplete the substrate for oxalate synthesis. Subcutaneous administration of ALN-GO1 resulted in potent, dose-dependent, and durable silencing of the mRNA encoding glycolate oxidase and increased serum glycolate concentrations in wild-type mice, rats, and nonhuman primates. ALN-GO1 also increased urinary glycolate concentrations in normal nonhuman primates and in a genetic mouse model of PH1. Notably, ALN-GO1 reduced urinary oxalate concentration up to 50% after a single dose in the genetic mouse model of PH1, and up to 98% after multiple doses in a rat model of hyperoxaluria. These data demonstrate the ability of ALN-GO1 to reduce oxalate production in preclinical models of PH1 across multiple species and provide a clear rationale for clinical trials with this compound.

  8. Calcium bioavailability and its relation to osteoporosis.

    PubMed

    Weaver, C M

    1992-06-01

    The balance of data suggests that calcium intake has a positive influence on bone mass in premenopausal women and has a preventive effect on the rate of bone loss in postmenopausal women. Even small advantages in bone mass provide great reductions in fracture rates. However, the majority of studies have tested the relationship of calcium intake and bone mass using calcium supplements. Few intervention studies have manipulated calcium intake through foods. Calcium is only useful to the skeleton once it is absorbed. Therefore, the bioavailability of dietary calcium becomes important in the prevention and treatment of osteoporosis. Isotopic tracer techniques have only recently been employed in the labeling of foods with calcium isotopes for evaluation of calcium absorption. Milk calcium is usually the referent food which is typically absorbed at 20-40% depending on the calcium status of the subject. The absorptive efficiency of most vegetable sources is as good or better than for dairy foods, unless they have high concentrations of oxalic acid (spinach, for example) or phytic acid (wheat bran cereal, for example). Few vegetable sources are concentrated sources of calcium. Therefore, it would be difficult to obtain adequate intakes of calcium to protect against osteoporosis without liberal use of dairy products in the diet. Alternately, calcium supplements provide concentrated amounts of absorbable calcium, but they do not provide other nutrients necessary for skeletal growth and maintenance.

  9. Oxalic acid degradation by a novel fungal oxalate oxidase from Abortiporus biennis.

    PubMed

    Grąz, Marcin; Rachwał, Kamila; Zan, Radosław; Jarosz-Wilkołazka, Anna

    2016-01-01

    Oxalate oxidase was identified in mycelial extracts of a basidiomycete Abortiporus biennis strain. Intracellular enzyme activity was detected only after prior lowering of the pH value of the fungal cultures by using oxalic or hydrochloric acids. This enzyme was purified using size exclusion chromatography (Sephadex G-25) and ion-exchange chromatography (DEAE-Sepharose). This enzyme exhibited optimum activity at pH 2 when incubated at 40°C, and the optimum temperature was established at 60°C. Among the tested organic acids, this enzyme exhibited specificity only towards oxalic acid. Molecular mass was calculated as 58 kDa. The values of Km for oxalate and Vmax for the enzyme reaction were 0.015 M and 30 mmol min(-1), respectively.

  10. The importance of meeting calcium needs with foods.

    PubMed

    Miller, G D; Jarvis, J K; McBean, L D

    2001-04-01

    Calcium can be obtained from foods naturally rich in calcium such as dairy foods, from calcium-fortified foods and beverages, from supplements or from a combination of these. Recognition of calcium's many health benefits, along with Americans' low calcium intake, has led to interest in how best to meet calcium needs. Foods are the preferred source of calcium. Milk and other dairy foods are the major source of calcium in the U.S. In addition, these foods provide substantial amounts of other essential nutrients. Consequently, intake of dairy foods improves the overall nutritional quality of the diet. Other foods such as some green leafy vegetables, legumes and cereals provide calcium, but generally in lower amounts per serving than do dairy foods. Also, some components such as phytates in cereals and oxalates in spinach reduce the bioavailability of calcium. Calcium-fortified foods and calcium supplements are an option for individuals who cannot meet their calcium needs from foods naturally containing this mineral. However, their intake cannot correct poor dietary patterns of food selection which underlie Americans' low calcium intake. Considering the adverse health and economic effects of low calcium intakes, strategies are needed to optimize calcium intake. A first step is to recognize factors influencing dietary calcium consumption. Substituting soft drinks for milk and eating away from home are among the barriers to adequate calcium intake. The American public needs to understand why consuming foods containing calcium is the best way to meet calcium needs and learn how to accomplish this objective.

  11. Why oral calcium supplements may reduce renal stone disease: report of a clinical pilot study

    PubMed Central

    Williams, C; Child, D; Hudson, P; Davies, G; Davies, M; John, R; Anandaram, P; De Bolla, A R

    2001-01-01

    Aims—To investigate whether increasing the daily baseline of gut calcium can cause a gradual downregulation of the active intestinal transport of calcium via reduced parathyroid hormone (PTH) mediated activation of vitamin D, and to discuss why such a mechanism might prevent calcium oxalate rich stones. To demonstrate the importance of seasonal effects upon the evaluation of such data. Methods—Within an intensive 24 hour urine collection regimen, daily calcium supplementation (500 mg) was given to five stone formers for a 10 week period during a six month crossover study. In a further population of patients on follow up for previous renal stone disease, observations were made on 1066 24 hour urine samples collected over five years in respect of seasonal effects relevant to the interpretation of the study. Results—In the group of patients on calcium supplements the following results were found. During calcium supplementation, the proportion of urine calcium to oxalate was higher (increased calcium to oxalate molar ratio), the 24 hour urine product of calcium and oxalate did not rise, and urine oxalate was lower during the first six weeks of supplementation. Twenty four hour urine calcium was 10.2% higher than baseline in the final four weeks of the 10 weeks of supplementation. Twenty four hour urine phosphate was 11.4% lower during the first six weeks of supplementation, but then rose while the patients were still on supplementation; renal tubular reabsorption of phosphate (TmP/GFR) mirrored the urine phosphate changes inversely. PTH was higher after stopping supplementation, but 1,25-(OH)2-cholecalciferol changes were not detected. In the 1066 urine samples collected over five years the following results were found. Calcium and oxalate excretion correlated positively and not inversely. Urine calcium and phosphate excretion were 5.5% and 2.5% higher, respectively, in "light" months of the year compared with "dark" months. A post summer decline in both urine

  12. Gas chromatographic determination of oxalic acid in foods.

    PubMed

    Ohkawa, H

    1985-01-01

    A new quantitative gas chromatographic (GC) method has been developed for the determination of oxalic acid in foods. Solid sample is extracted with water (soluble oxalic acid) or 2N hydrochloric acid (total oxalic acid) at room temperature. An aliquot of sample extract is evaporated to dryness, and the oxalic acid in the residue is methylated with 7% hydrochloric acid-methanol. The reaction mixture is extracted with chloroform, and dimethyl oxalate is quantitated by GC. Recovery of oxalic acid added to liquid samples averaged 100.6%; recoveries from extracts of solid samples were 96.2-99.5 and 97.2-100.1% for water and hydrochloric acid extractions, respectively. Results are shown for determination of oxalic acid in spinach and beverages. The technique is simple, rapid, and accurate, and small samples may be used. The limit of determination is 20 micrograms.

  13. Oxalate Nephropathy After Continuous Infusion of High-Dose Vitamin C as an Adjunct to Burn Resuscitation

    PubMed Central

    Pamplin, Jeremy; Studer, Lynette; Hughes, Rhome L.; King, Booker T.; Graybill, John C.; Chung, Kevin K.

    2016-01-01

    Fluid resuscitation is the foundation of management in burn patients and is the topic of considerable research. One adjunct in burn resuscitation is continuous, high-dose vitamin C (ascorbic acid) infusion, which may reduce fluid requirements and thus decrease the risk for over resuscitation. Research in preclinical studies and clinical trials has shown continuous infusions of high-dose vitamin C to be beneficial with decrease in resuscitative volumes and limited adverse effects. However, high-dose and low-dose vitamin C supplementation has been shown to cause secondary calcium oxalate nephropathy, worsen acute kidney injury, and delay renal recovery in non-burn patients. To the best of our knowledge, the authors present the first case series in burn patients in whom calcium oxalate nephropathy has been identified after high-dose vitamin C therapy. PMID:25812044

  14. Separation of americium, curium, and rare earths from high-level wastes by oxalate precipitation: experiments with synthetic waste solutions

    SciTech Connect

    Forsberg, C.W.

    1980-01-01

    The separation of trivalent actinides and rare earths from other fission products in high-level nuclear wastes by oxalate precipitation followed by ion exchange (OPIX) was experimentally investigated using synthetic wastes and a small-scale, continuous-flow oxalic acid precipitation and solid-liquid separation system. Trivalent actinide and rare earth oxalates are relatively insoluble in 0.5 to 1.0 M HNO/sub 3/ whereas other fission product oxalates are not. The continuous-flow system consisted of one or two stirred-tank reactors in series for crystal growth. Oxalic acid and waste solutions were mixed in the first tank, with the product solid-liquid slurry leaving the second tank. Solid-liquid separation was tested by filters and by a gravity settler. The experiments determined the fraction of rare earths precipitated and separated from synthetic waste streams as a function of number of reactors, system temperature, oxalic acid concentration, liquid residence time in the process, power input to the stirred-tank reactors, and method of solid-liquid separation. The crystalline precipitate was characterized with respect to form, size, and chemical composition. These experiments are only the first step in converting a proposed chemical flowsheet into a process flowsheet suitable for large-scale remote operations at high activity levels.

  15. Ultrafine calcium aerosol: Generation and use as a sorbent for sulfur in coal combustion. Volume 1, Experimental work: Final report, August 1, 1988--October 31, 1991

    SciTech Connect

    Alam, M.K.; Nahar, N.U.; Stewart, G.D.; Prudich, M.E.

    1991-11-01

    Studies conducted at Ohio University and elsewhere have demonstrated that ultrafine aerosols, which have the highest surface area per unit mass, have enhanced potential to efficiently remove sulfur dioxide form combustion gases. Therefore it is proposed to generate a very fine aerosol calcium-rich sorbent (or similar aerosols) for gas conditioning. The aerosol will be generated by vaporization of the sorbent compound and subsequent homogeneous nucleation. In experimental studies liquids as well as solids will be converted into ultrafine aerosols by using suitable aerosol generator. The aerosol generator could be a simple bubbler or a flame spray jet using powders of calcium ``Compounds. Studies will then be carried out, to determine the dynamics of sulfur dioxide capture by the ultrafine aerosol. The primary objective of this research was to generate fine aerosols and to use them for coal combustion SO{sub 2}/NO{sub x} gas removal purposes. From the background study on the dry scrubbing system, it can be concluded that the most important experimental parameters are addition ratio, reactor temperature, residence time, total inlet flow rate and inlet SO{sub 2} concentration. Addition ratio is the inlet molar ratio of calcium to sulfur. Before any experimentation, it was necessary to decide and investigate the values of each of the parameters. Each of these parameters were investigated individually and the effects on SO{sub 2} removal were determined.

  16. OXALATE MASS BALANCE DURING CHEMICAL CLEANING IN TANK 6F

    SciTech Connect

    Poirier, M.; Fink, S.

    2011-07-22

    The Savannah River Remediation (SRR) is preparing Tank 6F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRR personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 6F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate. Some conclusions from this work are: (1) Approximately 65% of the oxalate added as oxalic acid was removed with the decanted liquid. (2) Approximately 1% of the oxalate (added to the tank as oxalic acid) formed precipitates with compounds such as nickel, manganese, sodium, and iron (II), and was dissolved with nitric acid. (3) As much as 30% of the oxalate may have decomposed forming carbon dioxide. The balance does not fully account for all the oxalate added. The offset represents the combined uncertainty in the analyses and sampling.

  17. Bis(tetra-ethyl-ammonium) oxalate dihydrate.

    PubMed

    McNeese, Timothy J; Pike, Robert D

    2012-08-01

    The title compound, 2C(8)H(20)N(+)·C(2)O(4) (2-)·2H(2)O, synthesized by neutralizing H(2)C(2)O(4)·2H(2)O with (C(2)H(5))(4)NOH in a 1:2 molar ratio, is a deliquescent solid. The oxalate ion is nonplanar, with a dihedral angle between carboxyl-ate groups of 64.37 (2)°. O-H⋯O hydrogen bonds of moderate strength link the O atoms of the water mol-ecules and the oxalate ions into rings parallel to the c axis. The rings exhibit the graph-set motif R(4) (4)(12). In addition, there are weak C-H⋯O inter-actions in the crystal structure.

  18. Red facts: Oxalic acid. Fact sheet

    SciTech Connect

    Not Available

    1992-12-01

    All pesticides sold or used in the United States must be registered by EPA, based on scientific studies showing that they can be used without posing unreasonable risks to people or the environment. Because of advances in scientific knowledge, the law requires that pesticides which were first registered years ago be reregistered to ensure that they meet today's more stringent standards. Oxalic acid is registered for use as a disinfectant to control bacteria and germs, and as a sanitizer, in toilet bowls, urinals and bathroom premises. Oxalic acid also has many diverse, non-pesticidal, manufacturing and industrial uses including use in fabric printing and dyeing; bleaching straw hats; removing paint, varnish, rust or ink stains; and cleaning wood.

  19. Oxalic acid mineralization by electrochemical oxidation processes.

    PubMed

    Huang, Yao-Hui; Shih, Yu-Jen; Liu, Cheng-Hong

    2011-04-15

    In this study, two electrochemical oxidation processes were utilized to mineralize oxalic acid which was a major intermediate compound in the oxidation of phenols and other aromatic compounds. The anode rod and cathode net were made of a titanium coated with RuO(2)/IrO(2) (Ti-DSA) and stainless steel (S.S. net, SUS304), respectively. First, the Fered-Fenton process, which used H(2)O(2) and Fe(2+) as additive reagents, achieved 85% of TOC removal. It proceeded with ligand-to-metal charge-transfer (LMCT), which was evidenced by the accumulation of metallic foil on the selected cathode. However, in the absence of H(2)O(2)/Fe(2+), it showed a higher TOC removal efficiency while using Cl(-) only as an additive reagent due to the formation of hypochlorite on the anode. It was also found that the mineralization of oxalic acid by electrolysis generated hypochlorite better than the dosage of commercial hypochlorite without electricity. Also, pH value was a major factor that affected the mineralization efficiency of the oxalic acid due to the chlorine chemistry. 99% TOC removal could be obtained by Cl(-) electrolysis in an acidic environment.

  20. Urinary oxalate excretion in urolithiasis and nephrocalcinosis

    PubMed Central

    Neuhaus, T.; Belzer, T.; Blau, N.; Hoppe, B.; Sidhu, H.; Leumann, E.

    2000-01-01

    AIMS—To investigate urinary oxalate excretion in children with urolithiasis and/or nephrocalcinosis and to classify hyperoxaluria (HyOx).
METHODS—A total of 106 patients were screened. In those in whom the oxalate: creatinine ratio was increased, 24 hour urinary oxalate excretion was measured. Liver biopsy and/or genomic analysis was performed if primary hyperoxaluria (PH) was suspected. Stool specimens were examined for Oxalobacter formigenes in HyOx not related to PH type 1 or 2 (PH1, PH2) and in controls.
RESULTS—A total of 21 patients screened had HyOx (>0.5 mmol/24 h per 1.73 m2); they were classified into five groups. Eleven had PH (PH1 in nine and neither PH1 nor PH2 in two). Six had secondary HyOx: two enteric and four dietary. Four could not be classified. Seven patients had concomitant hypercalciuria. Only one of 12 patients was colonised with O formigenes compared to six of 13controls.
CONCLUSIONS—HyOx is an important risk factor for urolithiasis and nephrocalcinosis in children, and can coexist with hypercalciuria. A novel type of PH is proposed. Absence of O formigenes may contribute to HyOx not related to PH1.

 PMID:10735843

  1. Isolation of oxalic acid tolerating fungi and decipherization of its potential to control Sclerotinia sclerotiorum through oxalate oxidase like protein.

    PubMed

    Yadav, Shivani; Srivastava, Alok K; Singh, Dhanajay P; Arora, Dilip K

    2012-11-01

    Oxalic acid plays major role in the pathogenesis by Sclerotinia sclerotiorum; it lowers the pH of nearby environment and creates the favorable condition for the infection. In this study we examined the degradation of oxalic acid through oxalate oxidase and biocontrol of Sclerotinia sclerotiorum. A survey was conducted to collect the rhizospheric soil samples from Indo-Gangetic Plains of India to isolate the efficient fungal strains able to tolerate oxalic acid. A total of 120 fungal strains were isolated from root adhering soils of different vegetable crops. Out of 120 strains a total of 80 isolates were able to grow at 10 mM of oxalic acid whereas only 15 isolates were grow at 50 mM of oxalic acid concentration. Then we examined the antagonistic activity of the 15 isolates against Sclerotinia sclerotiorum. These strains potentially inhibit the growth of the test pathogen. A total of three potential strains and two standard cultures of fungi were tested for the oxalate oxidase activity. Strains S7 showed the maximum degradation of oxalic acid (23 %) after 60 min of incubation with fungal extract having oxalate oxidase activity. Microscopic observation and ITS (internally transcribed spacers) sequencing categorized the potential fungal strains into the Aspergillus, Fusarium and Trichoderma. Trichoderma sp. are well studied biocontrol agent and interestingly we also found the oxalate oxidase type activity in these strains which further strengthens the potentiality of these biocontrol agents.

  2. Urinary metabolic phenotyping the slc26a6 (chloride-oxalate exchanger) null mouse model.

    PubMed

    Garcia-Perez, Isabel; Villaseñor, Alma; Wijeyesekera, Anisha; Posma, Joram M; Jiang, Zhirong; Stamler, Jeremiah; Aronson, Peter; Unwin, Robert; Barbas, Coral; Elliott, Paul; Nicholson, Jeremy; Holmes, Elaine

    2012-09-07

    The prevalence of renal stone disease is increasing, although it remains higher in men than in women when matched for age. While still somewhat controversial, several studies have reported an association between renal stone disease and hypertension, but this may be confounded by a shared link with obesity. However, independent of obesity, hyperoxaluria has been shown to be associated with hypertension in stone-formers, and the most common type of renal stone is composed of calcium oxalate. The chloride-oxalate exchanger slc26a6 (also known as CFEX or PAT-1), located in the renal proximal tubule, was originally thought to have an important role in sodium homeostasis and thereby blood pressure control, but it has recently been shown to have a key function in oxalate balance by mediating oxalate secretion in the gut. We have applied two orthogonal analytical platforms (NMR spectroscopy and capillary electrophoresis with UV detection) in parallel to characterize the urinary metabolic signatures related to the loss of the renal chloride-oxalate exchanger in slc26a6 null mice. Clear metabolic differentiation between the urinary profiles of the slc26a6 null and the wild type mice were observed using both methods, with the combination of NMR and CE-UV providing extensive coverage of the urinary metabolome. Key discriminating metabolites included oxalate, m-hydroxyphenylpropionylsulfate (m-HPPS), trimethylamine-N-oxide, glycolate and scyllo-inositol (higher in slc26a6 null mice) and hippurate, taurine, trimethylamine, and citrate (lower in slc26a6 null mice). In addition to the reduced efficiency of anion transport, several of these metabolites (hippurate, m-HPPS, methylamines) reflect alteration in gut microbial cometabolic activities. Gender-related metabotypes were also observed in both wild type and slc26a6 null groups. Urinary metabolites that showed a sex-specific pattern included trimethylamine, trimethylamine-N-oxide, citrate, spermidine, guanidinoacetate, and 2

  3. Experimental study of fouling and cleaning of sintered stainless steel membrane in electro-microfiltration of calcium salt particles.

    PubMed

    Qin, Frank G F; Mawson, John; Zeng, Xin An

    2011-05-30

    Sintered stainless steel (SSS) microfiltration membranes, which served as electrode directly, were used for the experiment of separating Alamin, a calcium salt and protein containing particles, found in dairy processing. Fouling and cleaning of the SSS membranes under the application of an external electric field were studied. The imposed electric field was found, diverging the pH of permeate and retentate. This in turn altered the solubility of the calcium salt and impacted the performance of electro microfiltration membrane. Using electric field as an enhanced cleaning-in-place (CIP) method in back flushing SSS membrane was also studied.

  4. Biodegradation of oxalic acid from spinach using cereal radicles.

    PubMed

    Betsche, Thomas; Fretzdorff, Barbara

    2005-12-14

    A high level of oxalate intake constitutes a health risk for infants and metabolically disposed adults. Spinach, acclaimed for its many health benefits, is among the vegetables richest in oxalate. Blanching reduces oxalate unsatisfactorily and unspecifically. An alternative, biological method is proposed on the basis of rye seedlings or radicles (also barley and wheat) containing an oxalate-specific oxalate oxidase by nature. Dissolved oxalate (0.25 mM) was rapidly degraded in the presence of radicles (e.g., 70% within 100 min). With commercial deep-frozen spinach, near-complete degradation of soluble oxalate was achieved at pH 3.5. The total level of oxalate was reduced by half. Similarly high rates occurred from 18 to 35 degrees C. Even at 55 degrees C appreciable rates were observed. The seedling as a whole is effective, too, and enrichment with cereal-specific healthy components would occur. Removal of oxalate from other vegetables, juices, cycled process waters, or feeds is conceivable with fresh or heat-dried cereal seedlings or radicles.

  5. Characterization of oxalic acid pretreatment on lignocellulosic biomass using oxalic acid recovered by electrodialysis.

    PubMed

    Lee, Hong-Joo; Seo, Young-Jun; Lee, Jae-Won

    2013-04-01

    The properties of pretreated biomass and hydrolysate obtained by oxalic acid pretreatment using oxalic acid recovered through electrodialysis (ED) were investigated. Most of the oxalic acid was recovered and some of the fermentation inhibitors were removed by ED. For the original hydrolysate, the ethanol production was very low and fermentable sugars were not completely consumed by Pichia stipitis during fermentation. Ethanol yield was less than 0.12 g/g in all stage. For the ED-treated hydrolysate, ethanol production was increased by up to two times in all stages compared to the original hydrolysate. The highest ethanol production was 19.38 g/l after 72 h which correspond to the ethanol yield of 0.33 g/g. Enzymatic conversion of the cellulose to glucose for all the pretreated biomass was in the range of 76.03 and 77.63%. The hydrolysis rate on each pretreated biomass was not significantly changed when oxalic acid recovered by ED was used for pretreatment.

  6. Experimental evidence for 60 Hz magnetic fields operating through the signal transduction cascade. Effects on calcium influx and c-MYC mRNA induction.

    PubMed

    Liburdy, R P; Callahan, D E; Harland, J; Dunham, E; Sloma, T R; Yaswen, P

    1993-11-22

    We tested the hypothesis that early alterations in calcium influx induced by an imposed 60 Hz magnetic field are propagated down the signal transduction (ST) cascade to alter c-MYC mRNa induction. To test this we measured both ST parameters in the same cells following 60 Hz magnetic field exposures in a specialized annular ring device (220 G (22 mT), 1.7 mV/cm maximal E(induced), 37 degrees C, 60 min). Ca2+ influx is a very early ST marker that precedes the specific induction of mRNA transcripts for the proto-oncogene c-MYC, an immediate early response gene. In three experiments influx of 45Ca2+ in the absence of mitogen was similar to that in cells treated with suboptimal levels of Con-A (1 micrograms/ml). However, calcium influx was elevated 1.5-fold when lymphocytes were exposed to Con-A plus magnetic fields; this co-stimulatory effect is consistent with previous reports from our laboratory [FEBS Lett. 301 (1992) 53-59; FEBS Lett. 271 (1990) 157-160; Ann. N.Y. Acad. Sci. 649 (1992) 74-95]. The level of c-MYC mRNA transcript copies in non-activated cells and in suboptimally-activated cells was also similar, which is consistent with the above calcium influx findings. Significantly, lymphocytes exposed to the combination of magnetic fields plus suboptimal Con-A responded with an approximate 3.0-fold increase in band intensity of c-MYC mRNA transcripts. Importantly, transcripts for the housekeeping gene GAPDH were not influenced by mitogen or magnetic fields. We also observed that lymphocytes that failed to exhibit increased calcium influx in response to magnetic fields plus Con-A, also failed to exhibit an increase in total copies of c-MYC mRNA. Thus, calcium influx and c-MYC mRNA expression, which are sequentially linked via the signal transduction cascade in contrast to GAPDH, were both increased by magnetic fields. These findings support the above ST hypothesis and provide experimental evidence for a general biological framework for understanding magnetic field

  7. Reregistration eligibility document (RED): Oxalic acid

    SciTech Connect

    Not Available

    1992-12-01

    EPA is directed by the Federal Insecticide, Fungicide, and Rodenticide Act as amended in 1988 (FIFRA '88) to review all pesticide products containing active ingredients initially registered before November 1, 1984, and to reregister those products that have a substantially complete data base and do not pose unreasonable adverse effects to people or the environment. This pesticide reregistration program is to be completed by the late 1990's. The Reregistration Eligibility Document (or RED) for oxalic acid discusses the scientific data and other information supporting EPA's regulatory conclusion that products containing a pesticide do not pose unreasonable risks when used as directed by Agency-approved labeling, and are eligible for reregistration.

  8. Biocompatibility of Ricinus communis polymer with addition of calcium carbonate compared to titanium. Experimental study in guinea pigs

    PubMed Central

    Graça, Yorgos Luiz Santos De Salles; Opolski, Ana Cristina; Barboza, Barbara Evelin Gonçalves; Erbano, Bruna Olandoski; Mazzaro, Caroline Cantalejo; Klostermann, Flávia Caroline; Sucharski, Enéas Eduardo; Kubrusly, Luiz Fernando

    2014-01-01

    Objective The aim of the present investigation was to determine whether the difference in inflammatory tissue reaction between the Riccinus communis (castor) polymer with calcium carbonate and the titanium implant is statistically significant. Methods Thirty-two Cavia porcellus were allocated into four groups of eight animals each. We implanted the two types of materials in the retroperitoneal space of all the animals. They were euthanized at 7, 20, 30 and 40 days after surgery, and an histological study of the samples was conducted. Results All implants showed characteristics of chronic inflammation regardless of the material and timepoint of evaluation. There was no statistically significant difference between Pm+CaCO3 and Ti with regard to the presence of granulation tissue, tissue congestion, histiocytes, lymphocytes, neutrophils, giant cells, and fibrosis (P> 0.05). Conclusion The castor oil polymer plus calcium carbonate implant was not statistically different from the titanium implant regarding inflammatory tissue reaction. PMID:25140479

  9. [Formation of oxalate in oxaliplatin injection diluted with infusion solutions].

    PubMed

    Eto, Seiji; Yamamoto, Kie; Shimazu, Kounosuke; Sugiura, Toshimune; Baba, Kaori; Sato, Ayaka; Goromaru, Takeshi; Hagiwara, Yoshiaki; Hara, Keiko; Shinohara, Yoshitake; Takahashi, Kojiro

    2014-01-01

    Oxaliplatin use can cause acute peripheral neuropathy characterized by sensory paresthesias, which are markedly exacerbated by exposure to cold temperatures, and is a dose-limiting factor in the treatment of colorectal cancer.Oxalate is eliminated in a series of nonenzymatic conversions of oxaliplatin in infusion solutions or biological fluids.Elimination of oxalate from oxaliplatin has been suggested as one of the reasons for the development of acute neuropathy.In this study, we developed a high-performance liquid chromatography(HPLC)-based method to detect oxalate formation, and investigated the time dependent formation of oxalate in oxaliplatin diluted with infusion solutions.The results obtained showed that the amount of oxalate in the solution corresponded to 1.6% of oxaliplatin 8 h after oxaliplatin dilution with a 5% glucose solution. On the other hand, oxalate formation from oxaliplatin diluted with a saline solution was ten-fold higher than that from oxaliplatin diluted with the 5% glucose solution.Most patients who were intravenously injected with oxaliplatin experienced venous pain.As a preventive measure against venous pain, dexamethasone was added to the oxaliplatin injection.We measured the amount of oxalate formed in the dexamethasone-containing oxaliplatin injection diluted with a 5% glucose solution.The amount of oxalate formed when dexamethasone was added did not differ significantly from that formed when dexamethasone was not added.Thus, there are no clinical problems associated with the stability of oxaliplatin solutions.

  10. Total and soluble oxalate content of some Indian spices.

    PubMed

    Ghosh Das, Sumana; Savage, G P

    2012-06-01

    Spices, such as cinnamon, cloves, cardamom, garlic, ginger, cumin, coriander and turmeric are used all over the world as flavouring and colouring ingredients in Indian foods. Previous studies have shown that spices contain variable amounts of total oxalates but there are few reports of soluble oxalate contents. In this study, the total, soluble and insoluble oxalate contents of ten different spices commonly used in Indian cuisine were measured. Total oxalate content ranged from 194 (nutmeg) to 4,014 (green cardamom) mg/100 g DM, while the soluble oxalate contents ranged from 41 (nutmeg) to 3,977 (green cardamom) mg/100 g DM. Overall, the percentage of soluble oxalate content of the spices ranged from 4.7 to 99.1% of the total oxalate content which suggests that some spices present no risk to people liable to kidney stone formation, while other spices can supply significant amounts of soluble oxalates and therefore should be used in moderation.

  11. Determination of oxalate in black liquor by headspace gas chromatography.

    PubMed

    Li, Hailong; Chai, Xin-Sheng; DeMartini, Nikolai; Zhan, Huaiyu; Fu, Shiyu

    2008-05-30

    This study demonstrated a headspace gas chromatographic method (HS-GC) for the determination of oxalate content in black liquor (alkaline aqueous solution of inorganic chemicals and dissolved wood species from the alkaline pulping of wood). The method described in this paper is based on the reaction between oxalic and manganese dioxide in an acidic medium, in which oxalic acid is converted to carbon dioxide that is measured with a GC using a thermal conductivity detector. The challenge in developing this method was ensuring complete conversion of oxalic acid while minimizing the contribution of side reactions between carbohydrates, lignin and manganese dioxide to the carbon dioxide measured. It was found that a complete conversion of oxalate to carbon dioxide can be achieved within 3 min at a temperature of 70 degrees C; a MnO(2):C(oxalate) (concentration of H(2)C(2)O(4)+HC(2)O(4)(-)+C(2)O(4)(2-)) mole ratio of 60 and H(2)SO(4) concentration of 0.005-0.01 mol/L in the headspace vial. The method can detect concentrations as low as 0.39 microg of oxalate. The standard deviation was found to be 7% while recovery experiments with black liquor showed recoveries of 93-108% which were deemed acceptable for analysis of oxalate in an industrial sample such as black liquor.

  12. Production of oxalic acid by some fungi infected tubers.

    PubMed

    Faboya, O; Ikotun, T; Fatoki, O S

    1983-01-01

    Oxalic acid (as oxalate) was detected in four tubers commonly used for food in Nigeria-Dioscorea rotundata (White yam), Solanum tuberosum (Irish potato), Ipomoea batatas (Sweet potato), and Manihot esculenta (cassava). Whereas healthy I. batata had the highest oxalic acid content, healthy M. esculenta contained the lowest. When all tubers were artifically inoculated with four fungi-Penicillium oxalicum CURIE and THOM, Aspergillus niger VAN TIEGH, A. flavus and A. tamarii KITA, there was an increase in oxalate content/g of tuber tissue. The greatest amount of oxalate was produced by P. oxalicum in D. rotundata tuber. Consistently higher amounts of oxalate were produced by the four fungi in infected sweet potato tuber than in any other tuber and consistently lower amounts of oxalate were produced by the four fungi in Irish potato tuber. Differences in the carbohydrate type present in the tubers and in the biosynthesis pathway are thought to be responsible for variation in the production of oxalate in the different tubers by the four fungi used.

  13. [Current status of prevention and therapy of urinary calculi and peroral chemo-litholysis with special attention to the relationship of increased excretion of uric acid in oxalate lithiasis].

    PubMed

    Leskovar, P

    1980-03-01

    A survey shall be given of the present state of prevention and therapy of urolithiasis as well as of the up to now much restricted possibilities of the chemolitholysis. Particular attention is paid to calcium on account of its participation in the development of oxalate and phosphate calculi which together might be 70--80% of all calculi as well as to the rather limited possibilities of the reduction of the oxalate secretion in the urine. The encouragement of the oxalate lithiasis by increased uric acid in the urine as well as the reduction of the frequency of relapses not only of the concrements of the uric acid but also of the oxalate concrements by the uricostatic Allopurinol (e.g. zyloric) is dealt with.

  14. The influence of dicarboxylic acids: Oxalic acid and tartaric acid on the compressive strength of glass ionomer cements

    NASA Astrophysics Data System (ADS)

    Permana, Ahmadi Jaya; Setyawati, Harsasi; Hamami, Murwani, Irmina Kris

    2016-03-01

    Glass ionomer cement (GIC) has limitation on the mechanical properties especially compressive strength. The change of compressive strength of GIC by adding oxalic acid and tartaric acid has been investigated. Oxalic acid and tartaric acid was added to the liquid components at concentrations of 0 - 15% (w/w). Powder component of GIC was made from optimum experimental powder glass SiO2-Al2O3-CaF2. GIC was characterized by compressive strength test, SEM-EDX and FTIR. The addition of tartaric acid to GIC has greater improvement than addition of oxalic acid. The addition of tartaric acid at 10 % (w/w) to GIC has greatest value of compressive strength.

  15. Efficient electron-induced removal of oxalate ions and formation of copper nanoparticles from copper(II) oxalate precursor layers

    PubMed Central

    Rückriem, Kai; Grotheer, Sarah; Vieker, Henning; Penner, Paul; Beyer, André; Gölzhäuser, Armin

    2016-01-01

    Summary Copper(II) oxalate grown on carboxy-terminated self-assembled monolayers (SAM) using a step-by-step approach was used as precursor for the electron-induced synthesis of surface-supported copper nanoparticles. The precursor material was deposited by dipping the surfaces alternately in ethanolic solutions of copper(II) acetate and oxalic acid with intermediate thorough rinsing steps. The deposition of copper(II) oxalate and the efficient electron-induced removal of the oxalate ions was monitored by reflection absorption infrared spectroscopy (RAIRS). Helium ion microscopy (HIM) reveals the formation of spherical nanoparticles with well-defined size and X-ray photoelectron spectroscopy (XPS) confirms their metallic nature. Continued irradiation after depletion of oxalate does not lead to further particle growth giving evidence that nanoparticle formation is primarily controlled by the available amount of precursor. PMID:27547602

  16. A test of the hypothesis that oxalate secretion produces proximal tubule crystallization in primary hyperoxaluria type I.

    PubMed

    Worcester, Elaine M; Evan, Andrew P; Coe, Fredric L; Lingeman, James E; Krambeck, Amy; Sommers, Andre; Phillips, Carrie L; Milliner, Dawn

    2013-12-01

    The sequence of events by which primary hyperoxaluria type 1 (PH1) causes renal failure is unclear. We hypothesize that proximal tubule (PT) is vulnerable because oxalate secretion raises calcium oxalate (CaOx) supersaturation (SS) there, leading to crystal formation and cellular injury. We studied cortical and papillary biopsies from two PH1 patients with preserved renal function, and seven native kidneys removed from four patients at the time of transplant, after short-term (2) or longer term (2) dialysis. In these patients, and another five PH1 patients without renal failure, we calculated oxalate secretion, and estimated PT CaOx SS. Plasma oxalate was elevated in all PH1 patients and inverse to creatinine clearance. Renal secretion of oxalate was present in all PH1 but rare in controls. PT CaOx SS was >1 in all nonpyridoxine-responsive PH1 before transplant and most marked in patients who developed end stage renal disease (ESRD). PT from PH1 with preserved renal function had birefringent crystals, confirming the presence of CaOx SS, but had no evidence of cortical inflammation or scarring by histopathology or hyaluronan staining. PH1 with short ESRD showed CaOx deposition and hyaluronan staining particularly at the corticomedullary junction in distal PT while cortical collecting ducts were spared. Longer ESRD showed widespread cortical CaOx, and in both groups papillary tissue had marked intratubular CaOx deposits and fibrosis. CaOx SS in PT causes CaOx crystal formation, and CaOx deposition in distal PT appears to be associated with ESRD. Minimizing PT CaOx SS may be important for preserving renal function in PH1.

  17. Non-invasive identification of metal-oxalate complexes on polychrome artwork surfaces by reflection mid-infrared spectroscopy.

    PubMed

    Monico, Letizia; Rosi, Francesca; Miliani, Costanza; Daveri, Alessia; Brunetti, Brunetto G

    2013-12-01

    In this work a reflection mid-infrared spectroscopy study of twelve metal-oxalate complexes, of interest in art conservation science as alteration compounds, was performed. Spectra of the reference materials highlighted the presence of derivative-like and/or inverted features for the fundamental vibrational modes as result of the main contribution from the surface component of the reflected light. In order to provide insights in the interpretation of theses spectral distortions, reflection spectra were compared with conventional transmission ones. The Kramers-Kronig (KK) algorithm, employed to correct for the surface reflection distortions, worked properly only for the derivative-like bands. Therefore, to pay attention to the use of this algorithm when interpreting the reflection spectra is recommended. The outcome of this investigation was exploited to discriminate among different oxalates on thirteen polychrome artworks analyzed in situ by reflection mid-infrared spectroscopy. The visualization of the νs(CO) modes (1400-1200 cm(-1)) and low wavenumber bands (below 900 cm(-1)) in the raw reflection profiles allowed Ca, Cu and Zn oxalates to be identified. Further information about the speciation of different hydration forms of calcium oxalates were obtained by using the KK transform. The work proves reflection mid-infrared spectroscopy to be a reliable and sensitive spectro-analytical method for identifying and mapping different metal-oxalate alteration compounds on the surface of artworks, thus providing conservation scientists with a non-invasive tool to obtain information on the state of conservation and causes of alteration of artworks.

  18. The Structure and Function of OxlT, the Oxalate Transporter of Oxalobacter formigenes.

    PubMed

    Iyalomhe, Osigbemhe; Khantwal, Chandra M; Kang, Di Cody

    2015-08-01

    OxlT, the oxalate transporter of Oxalobacter formigenes, is a member of the Major Facilitator Superfamily of transporters (MFS), one of the largest groups of membrane proteins with substantial relevance to solute transport physiology, pharmacology, and possible drug development. MFS proteins transport a wide range of substrates such as organic and inorganic anions, sugars, drugs, and neurotransmitters. This review succinctly summarizes experimental work on a model MFS protein, OxlT, beginning with its identification as an electrogenic oxalate/formate exchanger, its three-dimensional structure, and discussion of biochemical and biophysical data that have shed further light on its structure and function. We also discuss the structure and function of OxlT in relation to notable MFS carriers such as LacY and GlpT.

  19. Deuterium MAS NMR studies of dynamics on multiple timescales: histidine and oxalic acid.

    PubMed

    Chan-Huot, Monique; Wimperis, Stephen; Gervais, Christel; Bodenhausen, Geoffrey; Duma, Luminita

    2015-01-12

    Deuterium ((2) H) magic-angle spinning (MAS) nuclear magnetic resonance is applied to monitor the dynamics of the exchanging labile deuterons of polycrystalline L-histidine hydrochloride monohydrate-d7 and α-oxalic acid dihydrate-d6 . Direct experimental evidence of fast dynamics is obtained from T1Z and T1Q measurements. Further motional information is extracted from two-dimensional single-quantum (SQ) and double-quantum (DQ) MAS spectra. Differences between the SQ and DQ linewidths clearly indicate the presence of motions on intermediate timescales for the carboxylic moiety and the D2 O in α-oxalic acid dihydrate, and for the amine group and the D2 O in L-histidine hydrochloride monohydrate. Comparison of the relaxation rate constants of Zeeman and quadrupolar order with the relaxation rate constants of the DQ coherences suggests the co-existence of fast and slow motional processes.

  20. The effects of the hydroalcohol extract of Rosa canina L. fruit on experimentally nephrolithiasic Wistar rats.

    PubMed

    Tayefi-Nasrabadi, Hossein; Sadigh-Eteghad, Saeed; Aghdam, Zahra

    2012-01-01

    This research evaluated the possible therapeutic potential of Rosa canina (RC) as a preventive agent in experimentally induced calcium oxalate (CaOx) nephrolithiasis with ethylene glycol (1% EG) in rats. In this experiment, 50 Wistar rats were divided randomly into five groups (n = 10). These groups received tap drinking water (group I), 1% EG (group II), 250 mg/kg RC + 1% EG (group III), 500 mg/kg RC + 1% EG (group IV), or 2.5 g/kg potassium citrate + 1% EG (group V) for a period of 30 days. Blood and urine were collected for biochemical analysis, and the liver and kidneys were prepared for total lipid peroxides, calcium content and histological evaluation. The extract was analysed for total phenolics, flavonoids, ascorbic acid, citric acid and radical scavenger activity. The supplementation of the hydromethanol RC extract contributed to reducing the kidney and liver lipid peroxides to optimum levels in rats that had been treated with EG-induced CaOx lithiasis. The extract also decreased renal and urinary calcium contents, decreased the size and number of CaOx calculi in the kidneys, and significantly increased citrate excretion without changing the volume, pH, or urinary concentrations of oxalate in comparison with the control group. According to these results, RC can be useful as a preventive agent against the formation of CaOx kidney stones.

  1. Citrate, oxalate, sodium, and magnesium levels in fresh juices of three different types of tomatoes: evaluation in the light of the results of studies on orange and lemon juices.

    PubMed

    Yilmaz, Erdal; Batislam, Ertan; Kacmaz, Murat; Erguder, Imge

    2010-06-01

    Fruit and vegetable juices containing citrate may be recommended as an alternative in mild to moderate level hypocitraturic calcium stone formers who cannot tolerate pharmacological treatment. Tomato has been proved a citrate-rich vegetable. Tomato juice usage as citrate sources in hypocitraturic recurrent stone formers were evaluated in the light of the results of studies on orange and lemon juices. Ten 100 ml samples were prepared from three different tomato types processed through a blender. These samples were examined in terms of citrate, oxalate, calcium, magnesium, and sodium contents. No difference was detected between the parameters tested in three different tomato juices. Fresh tomato juice may be useful in hypocitraturic recurrent stone formers due to its high content of citrate and magnesium, and low content of sodium and oxalate. As the three different types of tomatoes did not differ in terms of citrate, magnesium, sodium, and oxalate content, they may be useful for clinical use if also supported by clinical studies.

  2. Immobilization of oxalate-degrading enzymes into p(HEMA) for inhibiting encrustation on ureteral stents

    NASA Astrophysics Data System (ADS)

    Mellman, James Kenneth

    Ureteral stents develop calcium-bearing deposits, called encrustation, that diminish their biocompatibility due to complications, such as chronic abrasion to the lumen of the ureter wall and subsequent infection. A reduction of encrustation, namely calcium oxalate, will improve the lifetime, health care costs, and infection resistance of such devices. The purpose of this research project is to study oxalate-degrading enzymes entrapped into a coating material that will control the interface to the urinary environment for ureteral stents. The coating material was a lightly crosslinked poly(2-hydroxyethyl methacrylate) (p(HEMA)) matrix in which the active enzymes were entrapped within the bulk material's free volume. The swelling of p(HEMA) films was comparable in ddH2O and urine. This hydrophilic matrix allows oxalate anions to diffuse into the bulk so that enzyme activity against oxalate can lower its local concentration, and thereby reduce the supersaturation of calcium oxalate. Oxalate oxidase (OxO) and oxalate decarboxylase (OxDc) were the oxalate-degrading enzymes examined herein. Michaelis Menten kinetic models were applied to free and immobilized enzyme activity. A substrate inhibition model was applied to OxO. The free form of OxO had a Vmax of 1.8 +/- 0.1 muM/min-mug, a km of 1.8 +/- 0.1 mM, and a ks of 35.4 +/- 3.7 mM while the immobilized form had a Vmax of 1.2 +/- 0.2 muM/min-mug, a km of 4.1 +/- 0.6 mM, and a ks of 660 +/- 140 mM. The free form of OxDc had a Vmax of 23.5 +/- 1.4 muM/min-mug and a km of 0.5 +/- 0.1 mM while the immobilized form had a Vmax of 5.0 +/- 1.9 muM/min-mug and km of 23.2 +/- 9.1 mM. The enzyme activity was measured to indicate viable application conditions for the coating, such as storing the films in urine over time. The maximum activity was shown at pH 4.2 to 4.5 and activity drops to be negligible by pH 7.0. Storing the enzyme at pH 6.1 exhibited a larger retained activity than storing at pH 4.2, yet storing in urine showed

  3. Oxalic acid excretion after intravenous ascorbic acid administration.

    PubMed

    Robitaille, Line; Mamer, Orval A; Miller, Wilson H; Levine, Mark; Assouline, Sarit; Melnychuk, David; Rousseau, Caroline; Hoffer, L John

    2009-02-01

    Ascorbic acid is frequently administered intravenously by alternative health practitioners and, occasionally, by mainstream physicians. Intravenous administration can greatly increase the amount of ascorbic acid that reaches the circulation, potentially increasing the risk of oxalate crystallization in the urinary space. To investigate this possibility, we developed gas chromatography mass spectrometry methodology and sampling and storage procedures for oxalic acid analysis without interference from ascorbic acid and measured urinary oxalic acid excretion in people administered intravenous ascorbic acid in doses ranging from 0.2 to 1.5 g/kg body weight. In vitro oxidation of ascorbic acid to oxalic acid did not occur when urine samples were brought immediately to pH less than 2 and stored at -30 degrees C within 6 hours. Even very high ascorbic acid concentrations did not interfere with the analysis when oxalic acid extraction was carried out at pH 1. As measured during and over the 6 hours after ascorbic acid infusions, urinary oxalic acid excretion increased with increasing doses, reaching approximately 80 mg at a dose of approximately 100 g. We conclude that, when studied using correct procedures for sample handling, storage, and analysis, less than 0.5% of a very large intravenous dose of ascorbic acid is recovered as urinary oxalic acid in people with normal renal function.

  4. Oxalic acid and sclerotial differentiation of Polyporus umbellatus.

    PubMed

    Xing, Yong-Mei; Yin, Wan-Qiang; Liu, Meng-Meng; Wang, Chun-Lan; Guo, Shun-Xing

    2015-06-01

    The present investigation aimed to uncover the effects of exogenous oxalic acid during the sclerotial formation of Polyporus umbellatus, with an emphasis on determining the content of the endogenic oxalic acid in the fungus. To this end, the oxalic acid content of the vegetative mycelia, sclerotia, culture mediums and sclerotial exudate were measured using High Performance Liquid Chromatography (HPLC). Furthermore, the lipid peroxidation was estimated by detecting thiobarbituric bituric acid reactive substances (TBARS). The results showed that the exogenous oxalic acid caused a delay in sclerotial differentiation (of up to 9 or more days), suppressed the sclerotial biomass and decreased the lipid peroxidation significantly in a concentration-dependent manner. Oxalic acid was found at very low levels in the mycelia and the maltose medium, whereas it was found at high levels in the mycelia and sucrose medium. After sclerotial differentiation, oxalic acid accumulated at high levels in both the sclerotia and the sclerotial exudate. Oxalic acid was therefore found to inhibit P. umbellatus sclerotial formation.

  5. Calcium-activated K+ channels of mouse beta-cells are controlled by both store and cytoplasmic Ca2+: experimental and theoretical studies.

    PubMed

    Goforth, P B; Bertram, R; Khan, F A; Zhang, M; Sherman, A; Satin, L S

    2002-09-01

    A novel calcium-dependent potassium current (K(slow)) that slowly activates in response to a simulated islet burst was identified recently in mouse pancreatic beta-cells (Göpel, S.O., T. Kanno, S. Barg, L. Eliasson, J. Galvanovskis, E. Renström, and P. Rorsman. 1999. J. Gen. Physiol. 114:759-769). K(slow) activation may help terminate the cyclic bursts of Ca(2+)-dependent action potentials that drive Ca(2+) influx and insulin secretion in beta-cells. Here, we report that when [Ca(2+)](i) handling was disrupted by blocking Ca(2+) uptake into the ER with two separate agents reported to block the sarco/endoplasmic calcium ATPase (SERCA), thapsigargin (1-5 microM) or insulin (200 nM), K(slow) was transiently potentiated and then inhibited. K(slow) amplitude could also be inhibited by increasing extracellular glucose concentration from 5 to 10 mM. The biphasic modulation of K(slow) by SERCA blockers could not be explained by a minimal mathematical model in which [Ca(2+)](i) is divided between two compartments, the cytosol and the ER, and K(slow) activation mirrors changes in cytosolic calcium induced by the burst protocol. However, the experimental findings were reproduced by a model in which K(slow) activation is mediated by a localized pool of [Ca(2+)] in a subspace located between the ER and the plasma membrane. In this model, the subspace [Ca(2+)] follows changes in cytosolic [Ca(2+)] but with a gradient that reflects Ca(2+) efflux from the ER. Slow modulation of this gradient as the ER empties and fills may enhance the role of K(slow) and [Ca(2+)] handling in influencing beta-cell electrical activity and insulin secretion.

  6. Oxalic acid is available as a natural antioxidant in some systems.

    PubMed

    Kayashima, Tomoko; Katayama, Tetsuyuki

    2002-10-10

    Oxalic acid is found in a wide variety of plants. This study showed that oxalic acid suppressed in vitro lipid peroxidation in a concentration-dependent manner. Furthermore, oxalic acid reduced the rate of ascorbic acid oxidation in the presence of hydrogen peroxide and Cu(2+). These results suggest that oxalic acid is available as a natural antioxidant.

  7. The bioavailability of magnesium in spinach and the effect of oxalic acid on magnesium utilization examined in diets of magnesium-deficient rats.

    PubMed

    Kikunaga, S; Ishii, H; Takahashi, M

    1995-12-01

    Spinach was evaluated for its bioavailability of magnesium in the experiment with magnesium-deficient rats. The effect of oxalic acid on absorption of dietary magnesium was also examined in the same experiment. After there were significant differences in the body weight of the rats between the control group and the magnesium-deficient group, and after the number of dead rats increased, the magnesium-deficient rats were divided into six groups. They were pair-fed for 8 days on the magnesium-deficient diet, magnesium-deficient diet supplemented with raw powdered spinach (R-sp), boiled powdered spinach (B-sp), or fried powdered spinach (F-sp), control diet supplemented with oxalic acid (Ox-C), and control diet (+Mg). On the 10th day, there was no significant difference in the food intake of the rats between the control group and magnesium-deficient group. However, the body weight, and body weight gain of the rats increased more significantly in the control group than in those of the magnesium-deficient group. Also, the contents of calcium and phosphorus in the liver and kidneys, and serum calcium content increased significantly in the magnesium-deficient rats compared with those of the control rats. However, the serum magnesium content decreased significantly in the magnesium-deficient rats. An especially large amount of calcium was accumulated in the kidneys of the magnesium-deficient rats. At the end of the experimental period, there were no significant differences in the food intake, body weight and body weight gain of the rats among the control group and each of the spinach-added groups. The body weight and body weight gain of the Ox-C rats decreased significantly in comparison with those of the control group and each of the spinach-added groups. Although, there were no significant differences in the concentrations of serum minerals (Mg, Ca and P) among each of the groups, kidney magnesium, calcium and phosphorus, and liver magnesium and phosphorus were

  8. Species differences in Cl- affinity and in electrogenicity of SLC26A6-mediated oxalate/Cl- exchange correlate with the distinct human and mouse susceptibilities to nephrolithiasis.

    PubMed

    Clark, Jeffrey S; Vandorpe, David H; Chernova, Marina N; Heneghan, John F; Stewart, Andrew K; Alper, Seth L

    2008-03-01

    The mouse is refractory to lithogenic agents active in rats and humans, and so has been traditionally considered a poor experimental model for nephrolithiasis. However, recent studies have identified slc26a6 as an oxalate nephrolithiasis gene in the mouse. Here we extend our earlier demonstration of different anion selectivities of the orthologous mouse and human SLC26A6 polypeptides to investigate the correlation between species-specific differences in SLC26A6 oxalate/anion exchange properties as expressed in Xenopus oocytes and in reported nephrolithiasis susceptibility. We find that human SLC26A6 mediates minimal rates of Cl(-) exchange for Cl(-), sulphate or formate, but rates of oxalate/Cl(-) exchange roughly equivalent to those of mouse slc2a6. Both transporters exhibit highly cooperative dependence of oxalate efflux rate on extracellular [Cl(-)], but whereas the K(1/2) for extracellular [Cl(-)] is only 8 mM for mouse slc26a6, that for human SLC26A6 is 62 mM. This latter value approximates the reported mean luminal [Cl(-)] of postprandial human jejunal chyme, and reflects contributions from both transmembrane and C-terminal cytoplasmic domains of human SLC26A6. Human SLC26A6 variant V185M exhibits altered [Cl(-)] dependence and reduced rates of oxalate/Cl(-) exchange. Whereas mouse slc26a6 mediates bidirectional electrogenic oxalate/Cl(-) exchange, human SLC26A6-mediated oxalate transport appears to be electroneutral. We hypothesize that the low extracellular Cl(-) affinity and apparent electroneutrality of oxalate efflux characterizing human SLC26A6 may partially explain the high human susceptibility to nephrolithiasis relative to that of mouse. SLC26A6 sequence variant(s) are candidate risk modifiers for nephrolithiasis.

  9. A ferrous oxalate mediated photo-Fenton system: toward an increased biodegradability of indigo dyed wastewaters.

    PubMed

    Vedrenne, Michel; Vasquez-Medrano, Ruben; Prato-Garcia, Dorian; Frontana-Uribe, Bernardo A; Hernandez-Esparza, Margarita; de Andrés, Juan Manuel

    2012-12-01

    This study assessed the applicability of a ferrous oxalate mediated photo-Fenton pretreatment for indigo-dyed wastewaters as to produce a biodegradable enough effluent, likely of being derived to conventional biological processes. The photochemical treatment was performed with ferrous oxalate and hydrogen peroxide in a Compound Parabolic Concentrator (CPC) under batch operation conditions. The reaction was studied at natural pH conditions (5-6) with indigo concentrations in the range of 6.67-33.33 mg L(-1), using a fixed oxalate-to-iron mass ratio (C(2)O(4)(2-)/Fe(2+)=35) and assessing the system's biodegradability at low (257 mg L(-1)) and high (1280 mg L(-1)) H(2)O(2) concentrations. In order to seek the optimal conditions for the treatment of indigo dyed wastewaters, an experimental design consisting in a statistical surface response approach was carried out. This analysis revealed that the best removal efficiencies for Total Organic Carbon (TOC) were obtained for low peroxide doses. In general it was observed that after 20 kJ L(-1), almost every treated effluent increased its biodegradability from a BOD(5)/COD value of 0.4. This increase in the biodegradability was confirmed by the presence of short chain carboxylic acids as intermediate products and by the mineralization of organic nitrogen into nitrate. Finally, an overall decrease in the LC(50) for Artemia salina indicated a successful detoxification of the effluent.

  10. Kinetic challenges facing oxalate, malonate, acetoacetate, and oxaloacetate decarboxylases.

    PubMed

    Wolfenden, Richard; Lewis, Charles A; Yuan, Yang

    2011-04-20

    To compare the powers of the corresponding enzymes as catalysts, the rates of uncatalyzed decarboxylation of several aliphatic acids (oxalate, malonate, acetoacetate, and oxaloacetate) were determined at elevated temperatures and extrapolated to 25 °C. In the extreme case of oxalate, the rate of the uncatalyzed reaction at pH 4.2 was 1.1 × 10(-12) s(-1), implying a 2.5 × 10(13)-fold rate enhancement by oxalate decarboxylase. Whereas the enzymatic decarboxylation of oxalate requires O(2) and Mn(II), the uncatalyzed reaction is unaffected by the presence of these cofactors and appears to proceed by heterolytic elimination of CO(2).

  11. Structure and chemical composition of an experimentally formed apical barrier after the application of calcium-glycerophosphate.

    PubMed

    Viloria, I L; Yanagiguchi, K; Hayashi, Y

    2000-10-01

    Transformation in the structure and composition of calcium-glycerophosphate (Ca-GP) was investigated using a scanning electron microscope fitted with an energy dispersive X-ray microanalysis (EDX) system. Ca-GP was packed inside roots that were subsequently implanted into the mandibles of rats to stimulate the formation of an apical barrier. Scanning electron microscopic observations of packed Ca-GP revealed three types of structures: globular aggregates, plate or flake-like aggregates, and granular aggregates. The average Ca/P molar ratios of EDX by area mode--postoperatively obtained at days 1, 3, 5, and 7--were 1.300, 1.533, 1.472, and 1.495 (analytic area: 0.01 to 0.03 mm2) and those of EDX by point mode were 1.220, 1.451, 1.487, and 1.467 (analytic point: 0.05 micron 2). The magnesium (Mg) weight percentage was found to be approximately 1.9 at days 3, 5, and 7, similar to Mg-substituted whitlockite. These findings suggest that Ca-GP are transformed, over a period of 3 days into Mg-substituted whitlockite as a result of being hydrolyzed by tissue fluid.

  12. Production and Degradation of Oxalic Acid by Brown Rot Fungi

    PubMed Central

    Espejo, Eduardo; Agosin, Eduardo

    1991-01-01

    Our results show that all of the brown rot fungi tested produce oxalic acid in liquid as well as in semisolid cultures. Gloeophyllum trabeum, which accumulates the lowest amount of oxalic acid during decay of pine holocellulose, showed the highest polysaccharide-depolymerizing activity. Semisolid cultures inoculated with this fungus rapidly converted 14C-labeled oxalic acid to CO2 during cellulose depolymerization. The other brown rot fungi also oxidized 14C-labeled oxalic acid, although less rapidly. In contrast, semisolid cultures inoculated with the white rot fungus Coriolus versicolor did not significantly catabolize the acid and did not depolymerize the holocellulose during decay. Semisolid cultures of G. trabeum amended with desferrioxamine, a specific iron-chelating agent, were unable to lower the degree of polymerization of cellulose or to oxidize 14C-labeled oxalic acid to the extent or at the rate that control cultures did. These results suggest that both iron and oxalic acid are involved in cellulose depolymerization by brown rot fungi. PMID:16348522

  13. Acute oxalate nephropathy after ingestion of star fruit.

    PubMed

    Chen, C L; Fang, H C; Chou, K J; Wang, J S; Chung, H M

    2001-02-01

    Acute oxalate nephropathy associated with ingestion of star fruit (carambola) has not been reported before. We report the first two cases. These patients developed nausea, vomiting, abdominal pain, and backache within hours of ingesting large quantities of sour carambola juice; then acute renal failure followed. Both patients needed hemodialysis for oliguric acute renal failure, and pathologic examinations showed typical changes of acute oxalate nephropathy. The renal function recovered 4 weeks later without specific treatment. Sour carambola juice is a popular beverage in Taiwan. The popularity of star fruit juice is not compatible with the rare discovery of star fruit-associated acute oxalate nephropathy. Commercial carambola juice usually is prepared by pickling and dilution processes that reduce oxalate content markedly, whereas pure fresh juice or mild diluted postpickled juice for traditional remedies, as used in our cases, contain high quantities of oxalate. An empty stomach and dehydrated state may pose an additional risk for development of renal injury. To avoid acute oxalate nephropathy, pure sour carambola juice or mild diluted postpickled juice should not be consumed in large amounts, especially on an empty stomach or in a dehydrated state.

  14. Protective effect of Urtica dioica methanol extract against experimentally induced urinary calculi in rats.

    PubMed

    Zhang, Haiying; Li, Ning; Li, Kun; Li, Peng

    2014-12-01

    Renal calculi formation is one of the most common urological disorders. Urinary stone disease is a common disease, which affects 10‑12% of the population in industrialized countries. In males, the highest prevalence of the disease occurs between the age of 20 and 40 years, while in females, the highest incidence of the disease occurs later. Previous studies have shown that long‑term exposure to oxalate is toxic to renal epithelial cells and results in oxidative stress. In the present study, a methanolic extract of aerial parts of Urtica dioica was screened for antiurolithiatic activity against ethylene glycol and ammonium chloride‑induced calcium oxalate renal stones in male rats. In the control rats, ethylene glycol and ammonium chloride administration was observed to cause an increase in urinary calcium, oxalate and creatinine levels, as well as an increase in renal calcium and oxalate deposition. Histopathological observations revealed calcium oxalate microcrystal deposits in the kidney sections of the rats treated with ethylene glycol and ammonium chloride, indicating the induction of lithiasis. In the test rats, treatment with the methanolic extract of Urtica dioica was found to decrease the elevated levels of urinary calcium, oxalate and creatinine, and significantly decrease the renal deposition of calcium and oxalate. Furthermore, renal histological observations revealed a significant reduction in calcium oxalate crystal deposition in the test rats. Phytochemical analysis of the Urtica dioica extract was also performed using liquid chromatography‑electrospray ionization tandem mass spectrometry and high-performance liquid chromatography with photodiode array detection, to determine the chemical composition of the extract. The eight chemical constituents identified in the extract were protocatechuic acid, salicylic acid, luteolin, gossypetin, rutin, kaempferol‑3‑O‑rutinoside, kaempferol‑3‑O‑glucoside and chlorogenic acid. In conclusion

  15. Calcium - urine

    MedlinePlus

    ... into the urine, which causes calcium kidney stones Sarcoidosis Taking too much calcium Too much production of ... Milk-alkali syndrome Proximal renal tubular acidosis Rickets Sarcoidosis Vitamin D Review Date 5/3/2015 Updated ...

  16. Enteric oxalate elimination is induced and oxalate is normalized in a mouse model of primary hyperoxaluria following intestinal colonization with Oxalobacter.

    PubMed

    Hatch, Marguerite; Gjymishka, Altin; Salido, Eduardo C; Allison, Milton J; Freel, Robert W

    2011-03-01

    Oxalobacter colonization of rat intestine was previously shown to promote enteric oxalate secretion and elimination, leading to significant reductions in urinary oxalate excretion (Hatch et al. Kidney Int 69: 691-698, 2006). The main goal of the present study, using a mouse model of primary hyperoxaluria type 1 (PH1), was to test the hypothesis that colonization of the mouse gut by Oxalobacter formigenes could enhance enteric oxalate secretion and effectively reduce the hyperoxaluria associated with this genetic disease. Wild-type (WT) mice and mice deficient in liver alanine-glyoxylate aminotransferase (Agxt) exhibiting hyperoxalemia and hyperoxaluria were used in these studies. We compared the unidirectional and net fluxes of oxalate across isolated, short-circuited large intestine of artificially colonized and noncolonized mice. In addition, plasma and urinary oxalate was determined. Our results demonstrate that the cecum and distal colon contribute significantly to enteric oxalate excretion in Oxalobacter-colonized Agxt and WT mice. In colonized Agxt mice, urinary oxalate excretion was reduced 50% (to within the normal range observed for WT mice). Moreover, plasma oxalate concentrations in Agxt mice were also normalized (reduced 50%). Colonization of WT mice was also associated with marked (up to 95%) reductions in urinary oxalate excretion. We conclude that segment-specific effects of Oxalobacter on intestinal oxalate transport in the PH1 mouse model are associated with a normalization of plasma oxalate and urinary oxalate excretion in otherwise hyperoxalemic and hyperoxaluric animals.

  17. HIGH-TEMPERATURE, SHORT-TIME SULFATION OF CALCIUM- BASED SORBENTS. 2. EXPERIMENTAL DATA AND THEORETICAL MODEL PREDICTIONS

    EPA Science Inventory

    The fundamental processes for injection of CaCO3 and Ca(OH)2 for the removal of SO2 from combustion gases of coal-fired boilers are analyzed on the basis of experimental data and a comprehensive theoretical model. Sulfation data were obtained in a 30-kW isothermal gas-particle t...

  18. Preclinical Evaluation of Antiurolithiatic Activity of Viburnum opulus L. on Sodium Oxalate-Induced Urolithiasis Rat Model

    PubMed Central

    İlhan, Mert; Ergene, Burçin; Süntar, Ipek; Özbilgin, Serkan; Saltan Çitoğlu, Gülçin; Demirel, M. Ayşe; Keleş, Hikmet; Altun, Levent; Küpeli Akkol, Esra

    2014-01-01

    The aim of the present research is to evaluate the antiurolithiatic effect of the various extracts prepared from the fruits of Viburnum opulus L., in regard to its ethnobotanical record. To induce urolithiasis, 70 mg/kg sodium oxalate was injected to the rats which were housed individually in metabolic cages. The test materials were applied during 7 days. Biochemical (urine and serum parameters), histopathological and antioxidant (TBARs, TSH and GSH) assays were conducted. The urine samples were examined by light microscope for the determination of the calcium oxalate crystals. Lyophilized juice of V. opulus (LJVO) and lyophilized commercial juice of V. opulus (LCJVO) exerted potential antiurolithiatic activity which was attributed to its diuretic effect along with the inhibitory action on the oxalate levels and free radical production. We also determined the chlorogenic acid content of the LJVO by high-performance liquid chromatography (HPLC). Chlorogenic acid was determined by using Supelcosil LC-18 (250 × 4.6 mm, 5 µm) column and acetonitrile: water: 0.2% o-phosphoric acid as a mobile phase. The chlorogenic acid content of V. opulus was found to be 0.3227 mg/mL in fruit juice. The results obtained in this study have provided a scientific evidence for the traditional usage of V. opulus on passing kidney stones in Turkish folk medicine. PMID:25165481

  19. Oxalic acid enhances Cr tolerance in the accumulating plant Leersia hexandra Swartz.

    PubMed

    Wang, Dunqiu; Zhang, Xuehong; Liu, Jie; Zhu, Yinian; Zhang, Hui; Zhang, Aili; Jin, Xiaodan

    2012-12-01

    This study examined the relationship between oxalic acid and Cr tolerance in an accumulating plant Leersia hexandra Swartz. The plants grown in hydroponics were exposed to Cr at 0, 5, 30, and 60 mg/L (without oxalate), and 0, 40, and 80 mg/L concentrations of Cr (with 70 mg/L oxalate or without oxalate). The results showed that more than 50% of Cr in shoots was found in HCl-extracted fraction (chromium oxalate) when the plants were exposed to Cr. Cr supply significantly increased oxalate concentration in shoots of L. hexandra (p < 0.05), but did not increase oxalate concentration in roots. Under 80 mg/L Cr stress, electrolyte leakages from roots and shoots with oxalate treatment were both significantly lower than those without oxalate treatment (p < 0.05), indicating exogenous oxalate supply alleviated Cr-induced membrane damage. Oxalate added to growth solution ameliorated reduction of biomass and inhibition of root growth induced by Cr, which demonstrated that application of oxalate helped L. hexandra tolerate Cr stress. However, oxalate supply did not affect the Cr concentrations both in roots and shoots of L. hexandra. These results suggest that oxalic acid may act as an important chelator and takes part in detoxifying chromium in internal process of L. hexandra.

  20. Calcium addition at the Hubbard Brook Experimental Forest increases sugar storage, antioxidant activity and cold tolerance in native red spruce (Picea rubens).

    PubMed

    Halman, Joshua M; Schaberg, Paul G; Hawley, Gary J; Eagar, Christopher

    2008-06-01

    In fall (November 2005) and winter (February 2006), we collected current-year foliage of native red spruce (Picea rubens Sarg.) growing in a reference watershed and in a watershed treated in 1999 with wollastonite (CaSiO(3), a slow-release calcium source) to simulate preindustrial soil calcium concentrations (Ca-addition watershed) at the Hubbard Brook Experimental Forest (Thornton, NH). We analyzed nutrition, soluble sugar concentrations, ascorbate peroxidase (APX) activity and cold tolerance, to evaluate the basis of recent (2003) differences between watersheds in red spruce foliar winter injury. Foliar Ca and total sugar concentrations were significantly higher in trees in the Ca-addition watershed than in trees in the reference watershed during both fall (P=0.037 and 0.035, respectively) and winter (P=0.055 and 0.036, respectively). The Ca-addition treatment significantly increased foliar fructose and glucose concentrations in November (P=0.013 and 0.007, respectively) and foliar sucrose concentrations in winter (P=0.040). Foliar APX activity was similar in trees in both watersheds during fall (P=0.28), but higher in trees in the Ca-addition watershed during winter (P=0.063). Cold tolerance of foliage was significantly greater in trees in the Ca-addition watershed than in trees in the reference watershed (P<0.001). Our results suggest that low foliar sugar concentrations and APX activity, and reduced cold tolerance in trees in the reference watershed contributed to their high vulnerability to winter injury in 2003. Because the reference watershed reflects forest conditions in the region, the consequences of impaired physiological function caused by soil Ca depletion may have widespread implications for forest health.

  1. EPR Spin Trapping of an Oxalate-Derived Free Radical in the Oxalate Decarboxylase Reaction

    PubMed Central

    Imaram, Witcha; Saylor, Benjamin T.; Centonze, Christopher P.; Richards, Nigel G. J.; Angerhofer, Alexander

    2011-01-01

    EPR spin trapping experiments on bacterial oxalate decarboxylase from Bacillus subtilis under turn-over conditions are described. The use of doubly 13C-labeled oxalate leads to a characteristic splitting of the observed radical adducts using the spin trap N-tert-butyl-α-phenylnitrone linking them directly to the substrate. The radical was identified as the carbon dioxide radical anion which is a key intermediate in the hypothetical reaction mechanism of both decarboxylase and oxidase activities. X-ray crystallography had identified a flexible loop, SENS161-4, which acts as a lid to the putative active site. Site directed mutagenesis of the hinge amino acids, S161 and T165 was explored and showed increased radical trapping yields compared to the wild type. In particular, T165V shows approximately ten times higher radical yields while at the same time its decarboxylase activity was reduced by about a factor of ten. This mutant lacks a critical H-bond between T165 and R92 resulting in compromised control over its radical chemistry allowing the radical intermediate to leak into the surrounding solution. PMID:21277974

  2. P2X7 receptor-mediated calcium dynamics in HEK293 cells: experimental characterization and modelling approach

    NASA Astrophysics Data System (ADS)

    Di Garbo, A.; Alloisio, S.; Nobile, M.

    2012-04-01

    The P2X7 receptor (P2X7R) induces ionotropic Ca2 + signalling in different cell types. It plays an important role in the immune response and in the nervous system. Here, the mechanisms underlying intracellular Ca2 + variations evoked by 3‧-O-(4-benzoyl)benzoyl-ATP (BzATP), a potent agonist of the P2X7R, in transfected HEK293 cells, are investigated both experimentally and theoretically. We propose a minimal model of P2X7R that is capable of reproducing, qualitatively and quantitatively, the experimental data. This approach was also adopted for the P2X7R variant, which lacks the entire C-terminus tail (trP2X7R). Then we introduce a biophysical model describing the Ca2 + dynamics in HEK293. Our model gives an account of the ionotropic Ca2 + influx evoked by BzATP on the basis of the kinetics model of P2X7R. To explain the complex Ca2 + responses evoked by BzATP, the model predicted that an impairment in Ca2 + extrusion flux through the plasma membrane is a key factor for Ca2 + homeostasis in HEK293 cells.

  3. Communication: Remarkable electrophilicity of the oxalic acid monomer: an anion photoelectron spectroscopy and theoretical study.

    PubMed

    Buonaugurio, Angela; Graham, Jacob; Buytendyk, Allyson; Bowen, Kit H; Ryder, Matthew R; Keolopile, Zibo G; Haranczyk, Maciej; Gutowski, Maciej

    2014-06-14

    Our experimental and computational results demonstrate an unusual electrophilicity of oxalic acid, the simplest dicarboxylic acid. The monomer is characterized by an adiabatic electron affinity and electron vertical detachment energy of 0.72 and 1.08 eV (±0.05 eV), respectively. The electrophilicity results primarily from the bonding carbon-carbon interaction in the singly occupied molecular orbital of the anion, but it is further enhanced by intramolecular hydrogen bonds. The well-resolved structure in the photoelectron spectrum is reproduced theoretically, based on Franck-Condon factors for the vibronic anion → neutral transitions.

  4. Means for reducing oxalic acid to a product

    SciTech Connect

    Morduchowitz, A.; Sammells, A.F.

    1988-12-06

    This patent describes an apparatus for reducing oxalic acid to a product comprising: a cell including a separator for separating the cell into two chambers, a catholyte chamber and an anolyte chamber, each chamber having an inlet and an outlet; a porous anode arranged within the anolyte section in a manner so that an electrolyte entering through the inlet of the anolyte section will pass through the anode and exit through the outlet of the anolyte section; means for providing an electrolyte to the inlet of the anolyte chamber in a manner so that it will exit through the outlet of the anolyte chamber; means for providing a mixture of oxalic acid and an electrolyte to the inlet of the catholyte chamber; porous cathode means located in the catholyte chamber for reducing the oxalic acid in the oxalic acid-electrolyte mixture to the product within the cathode means when a d.c. voltage provided across the anode and the cathode means, the product exiting the cell by way of the catholyte chamber's outlet; and means for providing a d.c. voltage across the cathode means and the anode so as to cooperate in the reduction of the oxalic acid; and in which the cathode means includes a porous cathode having discrete sites of platinum and mercury as catalysts and the product is ethylene glycol.

  5. [Study of the diuretic efficacy and tolerability of therapy with Rocchetta mineral water in patients with recurrent calcium kidney stones].

    PubMed

    Trinchieri, A; Boccafoschi, C; Chisena, S; De Angelis, M; Seveso, M

    1999-04-01

    The diluition of urine decreases the risk of stone formation by lowering the concentration of calcium, oxalate and uric acid, but involves a simultaneous decrease of the concentration of the inhibitors of crystallization. On the other hand the ion content of the drinking water used for stone prevention could by itself modify urine composition. We tested the effect of the administration of a mild-calcium high-bicarbonate content water on urine composition of a group of calcium renal stone formers. A group of 40 calcium renal stone formers was instructed to drink 3 l/day of a mild-calcium (57 mg/l) and high-bicarbonate (180 mg/l) content water (Rocchetta) for a 7 day period. A 24-h collection was obtained before and after water administration for analyses of calcium, magnesium, oxalate and citrate. Urine volume was significantly increased after water administration (1601 +/- 357 vs 1878 +/- 339). Daily urinary calcium, magnesium and citrate were significantly increased, whereas daily urinary oxalate was unchanged after water administration. In conclusion the mild-calcium high-bicarbonate content water administration seems suitable for stone prevention because of the increased excretion of urinary inhibitors counterbalancing increased urinary calcium excretion.

  6. Oxalate Content of the Herb Good-King-Henry, Blitum Bonus-Henricus.

    PubMed

    Li, Wanying; Savage, Geoffrey P

    2015-05-12

    The total, soluble and insoluble oxalate contents of the leaves, stems and buds of Good-King-Henry (Blitum Bonus-Henricus) were extracted and measured using HPLC chromatography. The large, mature leaves contained 42% more total oxalate than in the small leaves and the soluble oxalate content of the large leaves was 33% higher than the smaller leaves. Cooking the mixed leaves, stems and buds in boiling water for two minutes significantly (p < 0.05) reduced the total oxalate when compared to the raw plant parts. Pesto sauce made from mixed leaves contained 257 mg total oxalate/100 g fresh weight; this was largely made up of insoluble oxalates (85% of the total oxalate content). Soup made from mixed leaves contained lower levels of total oxalates (44.26 ± 0.49 mg total oxalate/100 g fresh weight) and insoluble oxalate made up 49% of the oxalate contents. The levels of oxalates in the Good-King-Henry leaves were high, suggesting that the leaves should be consumed occasionally as a delicacy because of their unique taste rather than as a significant part of the diet. However, the products made from Good-King-Henry leaves indicated that larger amounts could be consumed as the oxalate levels were reduced by dilution and processing.

  7. Oxalate Content of the Herb Good-King-Henry, Blitum Bonus-Henricus

    PubMed Central

    Li, Wanying; Savage, Geoffrey P.

    2015-01-01

    The total, soluble and insoluble oxalate contents of the leaves, stems and buds of Good-King-Henry (Blitum Bonus-Henricus) were extracted and measured using HPLC chromatography. The large, mature leaves contained 42% more total oxalate than in the small leaves and the soluble oxalate content of the large leaves was 33% higher than the smaller leaves. Cooking the mixed leaves, stems and buds in boiling water for two minutes significantly (p < 0.05) reduced the total oxalate when compared to the raw plant parts. Pesto sauce made from mixed leaves contained 257 mg total oxalate/100 g fresh weight; this was largely made up of insoluble oxalates (85% of the total oxalate content). Soup made from mixed leaves contained lower levels of total oxalates (44.26 ± 0.49 mg total oxalate/100 g fresh weight) and insoluble oxalate made up 49% of the oxalate contents. The levels of oxalates in the Good-King-Henry leaves were high, suggesting that the leaves should be consumed occasionally as a delicacy because of their unique taste rather than as a significant part of the diet. However, the products made from Good-King-Henry leaves indicated that larger amounts could be consumed as the oxalate levels were reduced by dilution and processing. PMID:28231194

  8. Effects of mineral composition of drinking water on risk for stone formation and bone metabolism in idiopathic calcium nephrolithiasis.

    PubMed

    Marangella, M; Vitale, C; Petrarulo, M; Rovera, L; Dutto, F

    1996-09-01

    1. To assess whether the mineral content of drinking water influences both risk of stone formation and bone metabolism in idiopathic calcium nephrolithiasis, 21 patients were switched from their usual home diets to a 10 mmol calcium, low-oxalate, protein-controlled diet, supplemented with 21 of three different types of mineral water. Drinking water added 1, 6 and 20 mmol of calcium and 0.5, 10 and 50 mmol of bicarbonate respectively to the controlled diet. 2. The three controlled study periods lasted 1 month each and were separated by a 20 day washout interval. Blood and urine chemistries, including intact parathyroid hormone, calcitriol and two markers of bone resorption, were performed at the end of each study period. The stone-forming risk was assessed by calculating urine saturation with calcium oxalate (beta CaOx), calcium phosphate (beta bsh) and uric acid (beta UA). 3. The addition of any mineral water produced the expected increase in urine output and was associated with similar decreases in beta CaOx and beta UA, whereas beta bsh varied marginally. These equal decreases in beta CaOx, however, resulted from peculiar changes in calcium, oxalate and citrate excretion during each study period. The increase in overall calcium intake due to different drinking water induced modest increases in calcium excretion, whereas oxalate excretion tended to decrease. The changes in oxalate excretion during any one study period compared with another were significantly related to those in calcium intake. Citrate excretion was significantly higher with the high-calcium, alkaline water. 4. Parathyroid hormone, calcitriol and markers of bone resorption increased when patients were changed from the high-calcium, alkaline to the low-calcium drinking water. 5. We suggest that overall calcium intake may be tailored by supplying calcium in drinking water. Adverse effects on bone turnover with low-calcium diets can be prevented by giving high-calcium, alkaline drinking water, and the

  9. Vibrational dynamics of a non-degenerate ultrafast rotor: The (C12,C13)-oxalate ion

    PubMed Central

    Kuroda, Daniel G.; Abdo, Mohannad; Chuntonov, Lev; Smith, Amos B.; Hochstrasser, Robin M.

    2013-01-01

    Molecular ions undergoing ultrafast conformational changes on the same time scale of water motions are of significant importance in condensed phase dynamics. However, the characterization of systems with fast molecular motions has proven to be both experimentally and theoretically challenging. Here, we report the vibrational dynamics of the non-degenerate (C12,C13)-oxalate anion, an ultrafast rotor, in aqueous solution. The infrared absorption spectrum of the (C12,C13)-oxalate ion in solution reveals two vibrational transitions separated by approximately 40 cm−1 in the 1500–1600 cm−1 region. These two transitions are assigned to vibrational modes mainly localized in each of the carboxylate asymmetric stretch of the ion. Two-dimensional infrared spectra reveal the presence and growth of cross-peaks between these two transitions which are indicative of coupling and population transfer, respectively. A characteristic time of sub-picosecond cross-peaks growth is observed. Ultrafast pump-probe anisotropy studies reveal essentially the same characteristic time for the dipole reorientation. All the experimental data are well modeled in terms of a system undergoing ultrafast population transfer between localized states. Comparison of the experimental observations with simulations reveal a reasonable agreement, although a mechanism including only the fluctuations of the coupling caused by the changes in the dihedral angle of the rotor, is not sufficient to explain the observed ultrafast population transfer. PMID:24182056

  10. Calcium citrate for vulvar vestibulitis. A case report.

    PubMed

    Solomons, C C; Melmed, M H; Heitler, S M

    1991-12-01

    A woman had suffered from vulvar vestibulitis (vulvodynia) for four years. Pain from the disorder had disrupted her ability to function at work and home as well as sexually. An initial full range of treatments, including multiple operations, had produced no relief. Examination of the urine for evidence of excess oxalate, which has been shown to cause epithelial reactions similar to those found in vulvodynia, showed periodic hyperoxaluria and pH elevations related to the symptoms. Calcium citrate was given to modify the oxalate crystalluria. The symptoms were significantly reduced in three months, and the patient was pain free after one year. She was able to resume normal work, family, sexual and recreational activities. Withdrawal of the calcium citrate resulted in a return of the symptoms; reinstitution alleviated them. These findings suggest that further study of individualized metabolic factors that may underlie vulvodynia is warranted.

  11. Characterization of wheat germin (oxalate oxidase) expressed by Pichia pastoris

    SciTech Connect

    Pan, Heng-Yen; Whittaker, Mei M.; Bouveret, Romaric; Berna, Anne; Bernier, Francois; Whittaker, James W. . E-mail: jim@ebs.ogi.edu

    2007-05-18

    High-level secretory expression of wheat (Triticum aestivum) germin/oxalate oxidase was achieved in Pichia pastoris fermentation cultures as an {alpha}-mating factor signal peptide fusion, based on the native wheat cDNA coding sequence. The oxalate oxidase activity of the recombinant enzyme is substantially increased (7-fold) by treatment with sodium periodate, followed by ascorbate reduction. Using these methods, approximately 1 g (4 x 10{sup 4} U) of purified, activated enzyme was obtained following eight days of induction of a high density Pichia fermentation culture, demonstrating suitability for large-scale production of oxalate oxidase for biotechnological applications. Characterization of the recombinant protein shows that it is glycosylated, with N-linked glycan attached at Asn47. For potential biomedical applications, a nonglycosylated (S49A) variant was also prepared which retains essentially full enzyme activity, but exhibits altered protein-protein interactions.

  12. Sonolysis of an oxalic acid solution under xenon lamp irradiation.

    PubMed

    Tanaka, Hisashi; Harada, Hisashi

    2010-06-01

    The photosonolysis of oxalic acid was carried out in an Ar atmosphere. The detectable products of sonolysis were CO(2), CO, H(2), and H(2)O(2). The yield of CO(2) was higher than that for the sum of sonolysis and photolysis reactions. Namely, a synergistic effect was observed during simultaneous irradiations of 200 kHz ultrasound and Xe lamp. The degradation of oxalic acid was promoted by active species such as H(2)O(2) produced from water by sonolysis. An oxalic acid-H(2)O(2) complex is likely to be present in the solution, but could not be detected. The effects of not only the photo-irradiation but also the thermal or incident energy during Xe lamp illumination were also considered.

  13. Characterization of wheat germin (oxalate oxidase) expressed by Pichia pastoris

    PubMed Central

    Pan, Heng-Yen; Whittaker, Mei M.; Bouveret, Romaric; Berna, Anne; Bernier, François; Whittaker, James W.

    2007-01-01

    High-level secretory expression of wheat (Triticum aestivum) germin/oxalate oxidase was achieved in Pichia pastoris fermentation cultures as an α-mating factor signal peptide fusion, based on the native wheat cDNA coding sequence. The oxalate oxidase activity of the recombinant enzyme is substantially increased (7-fold) by treatment with sodium periodate, followed by ascorbate reduction. Using these methods, approximately 1 g (4×104 U) of purified, activated enzyme was obtained following eight days of induction of a high density Pichia fermentation culture, demonstrating suitability for large-scale production of oxalate oxidase for biotechnological applications. Characterization of the recombinant protein shows that it is glycosylated, with N-linked glycan attached at Asn47. For potential biomedical applications, a nonglycosylated (S49A) variant was also prepared which retains essentially full enzyme activity, but exhibits altered protein-protein interactions. PMID:17399681

  14. Oxalic acid adsorption states on the clean Cu(110) surface

    NASA Astrophysics Data System (ADS)

    Fortuna, Sara

    2016-11-01

    Carboxylic acids are known to assume a variety of configurations on metallic surfaces. In particular oxalic acid on the Cu(110) surface has been proposed to assume a number of upright configurations. Here we explore with DFT calculations the possible structures that oxalic acid can form on copper 110 at different protonation states, with particular attention at the possibility of forming structures composed of vertically standing molecules. In its fully protonated form it is capable of anchoring itself on the surface thanks to one of its hydrogen-free oxygens. We show the monodeprotonated upright molecule with two oxygens anchoring it on the surface to be the lowest energy conformation of a single oxalic molecules on the Cu(110) surface. We further show that it is possible for this configuration to form dense hexagonally arranged patterns in the unlikely scenario in which adatoms are not involved.

  15. Crystal structure of di­methyl­ammonium hydrogen oxalate hemi(oxalic acid)

    PubMed Central

    Diallo, Waly; Gueye, Ndongo; Crochet, Aurélien; Plasseraud, Laurent; Cattey, Hélène

    2015-01-01

    Single crystals of the title salt, Me2NH2 +·HC2O4 −·0.5H2C2O4, were isolated as a side product from the reaction involving Me2NH, H2C2O4 and Sn(n-Bu)3Cl in a 1:2 ratio in methanol or by the reaction of the (Me2NH2)2C2O4 salt and Sn(CH3)3Cl in a 2:1 ratio in ethanol. The asymmetric unit comprises a di­methyl­ammonium cation (Me2NH2 +), an hydrogenoxalate anion (HC2O4 −), and half a mol­ecule of oxalic acid (H2C2O4) situated about an inversion center. From a supra­molecular point of view, the three components inter­act together via hydrogen bonding. The Me2NH2 + cations and the HC2O4 − anions are in close proximity through bifurcated N—H⋯(O,O) hydrogen bonds, while the HC2O4 − anions are organized into infinite chains via O—H⋯O hydrogen bonds, propagating along the a-axis direction. In addition, the oxalic acid (H2C2O4) mol­ecules play the role of connectors between these chains. Both the carbonyl and hydroxyl groups of each diacid are involved in four inter­molecular inter­actions with two Me2NH2 + and two HC2O4 − ions of four distinct polymeric chains, via two N—H⋯O and two O—H⋯O hydrogen bonds, respectively. The resulting mol­ecular assembly can be viewed as a two-dimensional bilayer-like arrangement lying parallel to (010), and reinforced by a C—H⋯O hydrogen bond. PMID:25995858

  16. THORIUM OXALATE-URANYL ACETATE COUPLED PROCEDURE FOR THE SEPARATION OF RADIOACTIVE MATERIALS

    DOEpatents

    Gofman, J.W.

    1959-08-11

    The recovery of fission products from neutronirradiated uranium is described. The neutron-irradiated uranium is dissolved in acid and thorium oxalate is precipitated in ihe solution formed, whereby the fission products are carried on the thorium oxalate. The separated thorium oxalate precipitate is then dissolved in an aqueous oxalate solution and the solution formed is acidified, limiting ihe excess acidity to a maximum of 2 N, whereby thorium oxalate precipitates and carries lanthanum-rareearth- and alkaline-earth-metal fission products while the zirconium-fission-product remains in solution. This precipitate, too, is dissolved in an aqaeous oxalate solution at elevated temperature, and lanthanum-rare-earth ions are added to the solution whereby lanthanum-rare-earth oxalate forms and the lanthanum-rare-earth-type and alkalineearth-metal-type fission products are carried on the oxalate. The precipitate is separated from the solution.

  17. Plutonium oxalate precipitation for trace elemental determination in plutonium materials

    DOE PAGES

    Xu, Ning; Gallimore, David; Lujan, Elmer; ...

    2015-05-26

    In this study, an analytical chemistry method has been developed that removes the plutonium (Pu) matrix from the dissolved Pu metal or oxide solution prior to the determination of trace impurities that are present in the metal or oxide. In this study, a Pu oxalate approach was employed to separate Pu from trace impurities. After Pu(III) was precipitated with oxalic acid and separated by centrifugation, trace elemental constituents in the supernatant were analyzed by inductively coupled plasma-optical emission spectroscopy with minimized spectral interferences from the sample matrix.

  18. Dissolution of kaolinite induced by citric, oxalic, and malic acids.

    PubMed

    Wang, Xingxiang; Li, Qingman; Hu, Huafeng; Zhang, Taolin; Zhou, Yiyong

    2005-10-15

    Kaolinite is a dominant clay mineral in the soils in tropical and subtropical regions, and its dissolution has an influence on a variety of soil properties. In this work, kaolinite dissolution induced by three kinds of low-molecular-weight organic acid, i.e., citric, oxalic, and malic acids, was evaluated under far-from-equilibrium conditions. The rates of kaolinite dissolution depended on the kind and concentration of organic acids, with the sequence R(oxalate)>R(citrate)>R(malate). Chemical calculation showed the change in concentration of organic ligand relative to change in concentration of organic acid in suspensions of kaolinite and organic acid. The effect of organic acid on kaolinite dissolution was modeled by species of organic anionic ligand. For oxalic acid, L(2-)(oxalic) and HL(-)(oxalic) jointly enhanced the dissolution of kaolinite, but for malic and citric acids, HL(-)(malic) and H2L-(citric) made a higher contribution to the total dissolution rate of kaolinite than L(2-)(malic) and L(3-)(citric), respectively. For oxalic acid, the proposed model was R(Si)=1.89x10(-12)x[(25x)/(1+25x)]+1.93x10(-12)x[(1990x1)/(1+1990x1)] (R2=0.9763), where x and x1 denote the concentrations of HL(oxalic) and L(oxalic), respectively, and x1=10(-3.81)xx/[H+]. For malic acid, the model was R(Si)=4.79x10(-12)x[(328x)/(1+328x)]+1.67x10(-13)x[(1149x1)/(1+1149x1)] (R2=0.9452), where x and x1 denote the concentrations of HL(malic) and L(malic), respectively, and x1=10(-5.11)xx/[H+], and for citric acid, the model was R(Si)=4.73x10(-12)x[(845x)/(1+845x)]+4.68x10(-12)x[(2855x1)/(1+2855x1)] (R2=0.9682), where x and x1 denote the concentrations of H2L(citric) and L(citric), respectively, and [Formula: see text] .

  19. Investigation of the Decomposition Mechanism of Lithium Bis(oxalate)borate (LiBOB) Salt in the Electrolyte of an Aprotic Li–O2 Battery

    SciTech Connect

    Lau, Kah Chun; Lu, Jun; Low, John; Peng, Du; Wu, Huiming; Albishri, Hassan M.; Al-Hady, D. Abd; Curtiss, Larry A.; Amine, Khalil

    2014-03-13

    The stability of the lithium bis(oxalate) borate (LiBOB) salt against lithium peroxide (Li2O2) formation in an aprotic Li–O2 (Li–air) battery is investigated. From theoretical and experimental findings, we find that the chemical decomposition of LiBOB in electrolytes leads to the formation lithium oxalate during the discharge of a Li–O2 cell. According to density functional theory (DFT) calculations, the formation of lithium oxalate as the reaction product is exothermic and therefore is thermodynamically feasible. This reaction seems to be independent of solvents used in the Li–O2 cell, and therefore LiBOB is probably not suitable to be used as the salt in Li–O2 cell electrolytes.

  20. Determining the Structure of Oxalate Anion Using Infrared and Raman Spectroscopy Coupled with Gaussian Calculations

    ERIC Educational Resources Information Center

    Peterson, Karen I.; Pullman, David P.

    2016-01-01

    A laboratory project for the upper-division physical chemistry laboratory is described, and it combines IR and Raman spectroscopies with Gaussian electronic structure calculations to determine the structure of the oxalate anion in solid alkali oxalates and in aqueous solution. The oxalate anion has two limiting structures whose vibrational spectra…

  1. PREPARATION OF OXALATES OF METALS OF ATOMIC NUMBER GREATER THAN 88

    DOEpatents

    Duffield, R.B.

    1959-02-01

    A method is presented for the preparation of oxalates of metals of atomic number greater than 88. A solid peroxide of the heavy metal is contacted with an aqueous oxalic acid solution ai a temperature of about 50 C for a period of time sufficient to form the insoluble metal oxalate which is subsequentiy recovered as a pures crystalline compound.

  2. Metal accumulation without enhanced oxalate secretion in wood degraded by brown rot fungi.

    PubMed

    Schilling, Jonathan S; Jellison, Jody

    2006-08-01

    Brown rot fungi were incubated in agar and agar-wood microcosms containing metallic or hydroxide forms of Al, Cu, and Fe. Metal dissolution was associated with elevated oxalate concentrations in agar, but metals translocated into wood did not affect oxalate accumulation, crystal production, or decay rate, demonstrating a substrate-dependent oxalate dynamic.

  3. Genomic evaluation of oxalate-degrading transgenic soybean in response to Sclerotinia sclerotiorum infection

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxalate oxidases catalyze the degradation of oxalic acid (OA). Highly resistant transgenic soybean carrying an oxalate oxidase (OxO) gene and its susceptible parent soybean line, AC Colibri, were tested for genome-wide gene expression in response to the necrotrophic, OA producing pathogen Sclerotini...

  4. The abiotic degradation of soil organic matter to oxalic acid

    NASA Astrophysics Data System (ADS)

    Studenroth, Sabine; Huber, Stefan; Schöler, H. F.

    2010-05-01

    The abiotic degradation of soil organic matter to volatile organic compounds was studied intensely over the last years (Keppler et al., 2000; Huber et al., 2009). It was shown that soil organic matter is oxidised due to the presence of iron (III), hydrogen peroxide and chloride and thereby produces diverse alkyl halides, which are emitted into the atmosphere. The formation of polar halogenated compounds like chlorinated acetic acids which are relevant toxic environmental substances was also found in soils and sediments (Kilian et al., 2002). The investigation of the formation of other polar halogenated and non-halogenated compounds like diverse mono- and dicarboxylic acids is going to attain more and more importance. Due to its high acidity oxalic acid might have impacts on the environment e.g., nutrient leaching, plant diseases and negative influence on microbial growth. In this study, the abiotic formation of oxalic acid in soil is examined. For a better understanding of natural degradation processes mechanistic studies were conducted using the model compound catechol as representative for structural elements of the humic substances and its reaction with iron (III) and hydrogen peroxide. Iron is one of the most abundant elements on earth and hydrogen peroxide is produced by bacteria or through incomplete reduction of oxygen. To find suitable parameters for an optimal reaction and a qualitative and quantitative analysis method the following reaction parameters are varied: concentration of iron (III) and hydrogen peroxide, time dependence, pH-value and influence of chloride. Analysis of oxalic acid was performed employing an ion chromatograph equipped with a conductivity detector. The time dependent reaction shows a relatively fast formation of oxalic acid, the optimum yield is achieved after 60 minutes. Compared to the concentration of catechol an excess of hydrogen peroxide as well as a low concentration of iron (III) are required. In absence of chloride the

  5. Does the Use of Chitosan Contribute to Oxalate Kidney Stone Formation?

    PubMed Central

    Queiroz, Moacir Fernandes; Teodosio Melo, Karoline Rachel; Sabry, Diego Araujo; Sassaki, Guilherme Lanzi; Rocha, Hugo Alexandre Oliveira

    2014-01-01

    Chitosan is widely used in the biomedical field due its chemical and pharmacological properties. However, intake of chitosan results in renal tissue accumulation of chitosan and promotes an increase in calcium excretion. On the other hand, the effect of chitosan on the formation of calcium oxalate crystals (CaOx) has not been described. In this work, we evaluated the antioxidant capacity of chitosan and its interference in the formation of CaOx crystals in vitro. Here, the chitosan obtained commercially had its identity confirmed by nuclear magnetic resonance and infrared spectroscopy. In several tests, this chitosan showed low or no antioxidant activity. However, it also showed excellent copper-chelating activity. In vitro, chitosan acted as an inducer mainly of monohydrate CaOx crystal formation, which is more prevalent in patients with urolithiasis. We also observed that chitosan modifies the morphology and size of these crystals, as well as changes the surface charge of the crystals, making them even more positive, which can facilitate the interaction of these crystals with renal cells. Chitosan greatly influences the formation of crystals in vitro, and in vivo analyses should be conducted to assess the risk of using chitosan. PMID:25551781

  6. Preparation of Bi-Pb-Sr-Ca-Cu-O high T c superconducting material via oxalate route at various pH values

    NASA Astrophysics Data System (ADS)

    Hagberg, J.; Uusimäki, A.; Levoska, J.; Leppävuori, S.

    1989-09-01

    A method for coprecipitation of Bi-Pb-Sr-Ca-Cu-O superconducting material via the oxalate route is presented. Bismuth, lead, strontium, calcium and copper nitrates and oxalic acid are used as starting materials. The precipitation of precursor from these materials is studied at different pH values The compositions of the coprecipitated powders are determined by direct current plasma atomic emission spectrometry. Two useful pH regions for precipitation are found. The first is a low pH region between 2 to 4 and the second is a high pH region of over 10. The precursors and sintered bulk samples are investigated by TEM, SEM/EDS and XRD. Resistivity measurements are carried out. The composition of the decomposed precursor is found to be homogeneous. The decomposed precursor has a particle size of around 300 nm. The sintered material consists of approximately 50% of the high Tc phase and shows zero resistance at 104 K.

  7. A model of propagating calcium-induced calcium release mediated by calcium diffusion

    PubMed Central

    1989-01-01

    The effect of sudden local fluctuations of the free sarcoplasmic [Ca++]i in cardiac cells on calcium release and calcium uptake by the sarcoplasmic reticulum (SR) was calculated with the aid of a simplified model of SR calcium handling. The model was used to evaluate whether propagation of calcium transients and the range of propagation velocities observed experimentally (0.05-15 mm s(-1)) could be predicted. Calcium fluctuations propagate by virtue of focal calcium release from the SR, diffusion through the cytosol (which is modulated by binding to troponin and calmodulin and sequestration by the SR), and subsequently induce calcium release from adjacent release sites of the SR. The minimal and maximal velocities derived from the simulation were 0.09 and 15 mm s(-1) respectively. The method of solution involved writing the diffusion equation as a difference equation in the spatial coordinates. Thus, coupled ordinary differential equations in time with banded coefficients were generated. The coupled equations were solved using Gear's sixth order predictor-corrector algorithm for stiff equations with reflective boundaries. The most important determinants of the velocity of propagation of the calcium waves were the diastolic [Ca++]i, the rate of rise of the release, and the amount of calcium released from the SR. The results are consistent with the assumptions that calcium loading causes an increase in intracellular calcium and calcium in the SR, and an increase in the amount and rate of calcium released. These two effects combine to increase the propagation velocity at higher levels of calcium loading. PMID:2738577

  8. Production of battery grade materials via an oxalate method

    SciTech Connect

    Belharouak, Ilias; Amine, Khalil

    2014-04-29

    An active electrode material for electrochemical devices such as lithium ion batteries includes a lithium transition metal oxide which is free of sodium and sulfur contaminants. The lithium transition metal oxide is prepared by calcining a mixture of a lithium precursor and a transition metal oxalate. Electrochemical devices use such active electrodes.

  9. Acute Oxalate Nephropathy following Ingestion of Averrhoa bilimbi Juice

    PubMed Central

    George, Jacob; Kumar, Sajeev; Gracious, Noble

    2014-01-01

    Plant toxins are known to cause acute kidney injury in tropical countries. We report two cases of acute kidney injury with tubular oxalate deposition following ingestion of Averrhoa bilimbi fruit juice. Both patients had complete renal recovery though one required dialytic support. PMID:24995136

  10. Production of battery grade materials via an oxalate method

    SciTech Connect

    Belharouak, Ilias; Amine, Khalil

    2016-05-17

    An active electrode material for electrochemical devices such as lithium ion batteries includes a lithium transition metal oxide which is free of sodium and sulfur contaminants. The lithium transition metal oxide is prepared by calcining a mixture of a lithium precursor and a transition metal oxalate. Electrochemical devices use such active electrodes.

  11. Crystal growth methods dedicated to low solubility actinide oxalates

    NASA Astrophysics Data System (ADS)

    Tamain, C.; Arab-Chapelet, B.; Rivenet, M.; Grandjean, S.; Abraham, F.

    2016-04-01

    Two novel crystal growth syntheses dedicated to low solubility actinide-oxalate systems and adapted to glove box handling are described. These methods based on the use of precursors of either actinide metal or oxalic acid have been optimized on lanthanide systems (analogue of actinides(III)) and then assessed on real actinide systems. They allow the synthesis of several actinide oxalate single crystals, Am2(C2O4)3(H2O)3·xH2O, Th(C2O4)2·6H2O, M2+x[PuIV2-xPuIIIx(C2O4)5]·nH2O and M1-x[PuIII1-xPuIVx(C2O4)2·H2O]·nH2O. It is the first time that these well-known compounds are formed by crystal growth methods, thus enabling direct structural studies on transuranic element systems and acquisition of basic data beyond deductions from isomorphic (or not) lanthanide compounds. Characterizations by X-ray diffraction, UV-visible solid spectroscopy, demonstrate the potentialities of these two crystal growth methods to obtain oxalate compounds.

  12. Oxalate Mass Balance During Chemical Cleaning in Tank 5F

    SciTech Connect

    Poirier, M.; Fink, S.

    2011-07-08

    The Savannah River Site (SRS) is preparing Tank 5F for closure. The first step in preparing the tank for closure is mechanical sludge removal. Following mechanical sludge removal, SRS performed chemical cleaning with oxalic acid to remove the sludge heel. Personnel are currently assessing the effectiveness of the chemical cleaning to determine whether the tank is ready for closure. SRS personnel collected liquid samples during chemical cleaning and submitted them to Savannah River National Laboratory (SRNL) for analysis. Following chemical cleaning, they collected a solid sample (also known as 'process sample') and submitted it to SRNL for analysis. The authors analyzed these samples to assess the effectiveness of the chemical cleaning process. Analysis of the anions showed the measured oxalate removed from Tank 5F to be approximately 50% of the amount added in the oxalic acid. To close the oxalate mass balance, the author collected solid samples, leached them with nitric acid, and measured the concentration of cations and anions in the leachate.

  13. Formation of solid solutions between racemic and enantiomeric citalopram oxalate.

    PubMed

    de Diego, Heidi Lopez; Bond, Andrew D; Dancer, Robert James

    2011-05-01

    The X-ray powder diffractograms of racemic citalopram oxalate and (S)-citalopram oxalate are very similar, but the melting point of the racemate is higher than that of the pure enantiomer. The higher melting point indicates that the racemate is a racemic compound, rather than a conglomerate. The crystal structure of the enantiomer contains two molecules of (S)-citalopram in the asymmetric unit. The conformation of the two molecules is different but they approximate mirror images of each other if the aromatic groups are interchanged. The crystal structure of the racemate is essentially isostructural with that of the enantiomer, having almost the same cell parameters but containing a crystallographic inversion centre that is not retained in the enantiomer structure. The closely-comparable crystal structures permit solid solutions to be formed between racemic and enantiomeric citalopram oxalate. Phase diagrams of the (R)-citalopram and (S)-citalopram oxalate system are constructed, and they show that solid solutions are formed at all ratios of the two enantiomers.

  14. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R.

    2012-02-22

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. For 6 M HNO{sub 3}, 10.5 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2 g/L and 0.25 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}.

  15. The effects of a whole-watershed calcium addition on the chemistry of stream storm events at the Hubbard Brook Experimental Forest in NH, USA.

    PubMed

    Cho, Youngil; Driscoll, Charles T; Blum, Joel D

    2009-10-01

    Patterns of storm runoff chemistry from a wollastonite (calcium-silicate mineral, CaSiO(3)) treated watershed (W1) were compared with a reference watershed (W6) at the Hubbard Brook Experimental Forest (HBEF) in New Hampshire (NH), USA to investigate the role of Ca(2+) supply in the acid-base status of stream chemistry. In the summer of 2003, six storm events were studied in W1 and W6 to evaluate the effects of the wollastonite treatment on the episodic acidification of stream waters. Although mean values of Ca(2+) concentrations decreased slightly from 33.8 to 31.7 mumol/L with increasing stream discharge in W1 during the events, the mean value of acid neutralizing capacity (ANC) was positive (1.2 mueq/L) during storm events, compared to negative values (-0.2 mueq/L) in W6. This pattern is presumably due to enhanced Ca(2+) supply in W1 (20.7 to 29.0% of dissolved Ca(2+) derived from the added wollastonite) to stream water as a result of interflow along shallow flowpaths. In addition, the application of wollastonite increased pH and dissolved silica (H(4)SiO(4)) concentrations, and decreased the concentration of inorganic monomeric Al (Al(i)) in W1 in comparison with W6 during storm events. Despite an increase in SO(4)(2-) concentration, likely due to desorption of sulfate from soil after the treatment, the watershed showed an increase in ANC compared to the reference watershed, serving to mitigate episodic acidification.

  16. Observation of calcium phosphate powder mixed with an adhesive monomer experimentally developed for direct pulp capping and as a bonding agent.

    PubMed

    Katoh, Yoshiroh; Suzuki, Masaya; Kato, Chikage; Shinkai, Koichi; Ogawa, Masaaki; Yamauchi, Junichi

    2010-01-01

    In this study, morphological shape, elemental distribution and elution properties of Ca, P, Mg in four types of calcium phosphate powder were investigated using SEM, EPMA and ICP-AES. Calcium phosphate powder: OHAp, DCPD, beta-TCP and OCP were observed in the white powder form and in the photopolymerized adhesive monomer they scattered like dispersed fillers in resin composite. In elemental analysis, CaKalpha showed a relatively high concentration in relation to PKalpha. In elution analysis, each calcium phosphate showed different elution of Ca and P. But Mg was almost equal to the detection limit of ICP-AES. Namely it was suggested that reparative dentin formation was effectively promoted under the following conditions: a calcification promoting effect by direct contact of the calcium phosphate powder, an ionic effect of Ca and P eluted from the powder located in the vicinity of the exposed pulp and environmental pH change of the surface in exposed pulp.

  17. Calcium in diet

    MedlinePlus

    ... of calcium dietary supplements include calcium citrate and calcium carbonate. Calcium citrate is the more expensive form of ... the body on a full or empty stomach. Calcium carbonate is less expensive. It is absorbed better by ...

  18. Cloning and sequencing of two Ceriporiopsis subvermispora bicupin oxalate oxidase allelic isoforms: implications for the reaction specificity of oxalate oxidases and decarboxylases.

    PubMed

    Escutia, Marta R; Bowater, Laura; Edwards, Anne; Bottrill, Andrew R; Burrell, Matthew R; Polanco, Rubén; Vicuña, Rafael; Bornemann, Stephen

    2005-07-01

    Oxalate oxidase is thought to be involved in the production of hydrogen peroxide for lignin degradation by the dikaryotic white rot fungus Ceriporiopsis subvermispora. This enzyme was purified, and after digestion with trypsin, peptide fragments of the enzyme were sequenced using quadrupole time-of-flight mass spectrometry. Starting with degenerate primers based on the peptide sequences, two genes encoding isoforms of the enzyme were cloned, sequenced, and shown to be allelic. Both genes contained 14 introns. The sequences of the isoforms revealed that they were both bicupins that unexpectedly shared the greatest similarity to microbial bicupin oxalate decarboxylases rather than monocupin plant oxalate oxidases (also known as germins). We have shown that both fungal isoforms, one of which was heterologously expressed in Escherichia coli, are indeed oxalate oxidases that possess < or =0.2% oxalate decarboxylase activity and that the organism is capable of rapidly degrading exogenously supplied oxalate. They are therefore the first bicupin oxalate oxidases to have been described. Heterologous expression of active enzyme was dependent on the addition of manganese salts to the growth medium. Molecular modeling provides new and independent evidence for the identity of the catalytic site and the key amino acid involved in defining the reaction specificities of oxalate oxidases and oxalate decarboxylases.

  19. The effects of oxalate-containing products on the exposed dentine surface: an SEM investigation.

    PubMed

    Gillam, D G; Mordan, N J; Sinodinou, A D; Tang, J Y; Knowles, J C; Gibson, I R

    2001-11-01

    In-office products containing oxalates have been claimed to be clinically effective in reducing dentine sensitivity, although there has been limited supporting clinical data. The rationale for their use appears to be based on their potential to act as occluding and/or nerve desensitizing agents. Four commercially available oxalate-containing products were applied to etched dentine discs and the extent of tubule occlusion was observed by scanning electron microscopy. Tenure Quick (aluminium oxalate), Sensodyne Sealant (ferric oxalate) and MS Coat (oxalic acid) covered the dentine surface and occluded the tubules. However, Butler Protect (potassium oxalate) did not cover the surface to any great extent but provided some occlusion. The presence of oxalates after application to glass slides and dentine discs was examined using thin film X-ray diffraction. From samples on glass, only potassium oxalate could be clearly identified (JCPDS 14-0845). No oxalate was detected on dentine discs in either thin film geometry or standard theta two theta mode. We have demonstrated that professionally applied in-office products containing oxalate are capable of covering the dentine surface and/or occluding the tubules to varying degrees. However, X-ray diffraction analysis was unable to confirm the oxalate profile for all products as described in the available commercial literature.

  20. Method of forming yttria-gadolinia ceramic scintillator from ammonium dispersed oxalate precipitates

    SciTech Connect

    Dole, S.L.; Greskovich, C.D.

    1992-03-31

    This patent describes a method of forming a polycrystalline translucent-to-transparent yttria-gadolinia composition scintillator that does not require milling. It comprises: coprecipitating oxalates of the yttria-gadolinia composition, drying the oxalates at about 75{degrees} to 125{degrees}C.; dispersing the oxalates by agitating an admixture of an aqueous suspension of the oxalates, and an effective amount of an ammonium hydroxide solution to disperse agglomerations of the oxalates; calcining the oxalates to substantially fully oxidize the oxalates and form a powder of the yttria-gadolinia composition; cold pressing the powder to form a compact; and sintering the compact in a reducing atmosphere or vacuum to form the polycrystalline translucent-to-transparent yttria-gadolinia scintillator.

  1. Subcellular localization of calcium deposits during zebrafish (Danio rerio) oogenesis.

    PubMed

    Golpour, Amin; Pšenička, Martin; Niksirat, Hamid

    2016-01-01

    Calcium plays prominent roles in regulating a broad range of physiological events in reproduction. The aim of this study was to describe the subcellular distribution of calcium deposits during stages of oogenesis in zebrafish using a combined oxalate-pyroantimonate technique. The oocyte development of zebrafish was categorized into four stages: primary growth, cortical-alveolus, vitellogenic, and maturation, based on morphological criteria. Calcium deposits in the primary growth stage were detected in the cytoplasm, mitochondria, nucleus, and follicular cells. At the cortical-alveolus stage, calcium particles were transported from follicular cells and deposited in the cortical alveoli. In the vitellogenic stage, some cortical alveoli were compacted and transformed from flocculent electron-lucent to electron-dense objects with the progression of the stage. Calcium deposits were transformed from larger to smaller particles, coinciding with compaction of cortical alveoli. In the maturation stage, calcium deposits in all oocyte compartments decreased, with the exception of those in mitochondria. The proportion of area covered by calcium deposits in the mitochondria and cortical alveoli of oocytes at different stages of development was significantly different (p<0.05). The extent of calcium deposits in the cortical alveoli of mature oocytes was substantially lower than in earlier stages. Basic information about calcium distribution during zebrafish oogenesis may contribute to better understanding of its role in oogenesis.

  2. Calcium - ionized

    MedlinePlus

    ... 245. Read More Acute kidney failure Albumin - blood (serum) test Bone tumor Calcium blood test Hyperparathyroidism Hypoparathyroidism Malabsorption Milk-alkali syndrome Multiple myeloma Osteomalacia Paget disease of the bone Rickets Sarcoidosis Vitamin D Review ...

  3. Calcium Carbonate.

    PubMed

    Al Omari, M M H; Rashid, I S; Qinna, N A; Jaber, A M; Badwan, A A

    2016-01-01

    Calcium carbonate is a chemical compound with the formula CaCO3 formed by three main elements: carbon, oxygen, and calcium. It is a common substance found in rocks in all parts of the world (most notably as limestone), and is the main component of shells of marine organisms, snails, coal balls, pearls, and eggshells. CaCO3 exists in different polymorphs, each with specific stability that depends on a diversity of variables.

  4. GADOLINIUM OXALATE SOLUBILITY MEASUREMENTS IN NITRIC ACID SOLUTIONS

    SciTech Connect

    Pierce, R. A.

    2012-03-12

    HB-Line will begin processing Pu solutions during FY2012 that will involve the recovery of Pu using oxalate precipitation and filtration. After the precipitation and filtration processes, the filtrate solution will be transferred from HB-Line to H-Canyon. The presence of excess oxalate and unfiltered Pu oxalate solids in these solutions create a criticality safety issue if they are sent to H-Canyon without controls in H-Canyon. One approach involves H-Canyon receiving the filtrate solution into a tank that is poisoned with soluble gadolinium (Gd). Decomposition of the oxalate will occur within a subsequent H-Canyon vessel. The receipt of excess oxalate into the H-Canyon receipt tanks has the potential to precipitate a portion of the Gd poison in the receipt tanks. Because the amount of Gd in solution determines the maximum amount of Pu solids that H-Canyon can receive, H-Canyon Engineering requested that SRNL determine the solubility of Gd in aqueous solutions of 4-10 M nitric acid (HNO{sub 3}), 4-12 g/L Gd, and 0.15-0.25 M oxalic acid (H{sub 2}C{sub 2}O{sub 4}) at 25 °C. The target soluble Gd concentration is 6 g/L. The data indicate that the target can be achieved above 6 M HNO{sub 3} and below 0.25 M H{sub 2}C{sub 2}O{sub 4}. At 25 °C, for 6 M HNO{sub 3}, 11 g/L and 7 g/L Gd are soluble in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. In 4 M HNO{sub 3}, the Gd solubility drops significantly to 2.5 g/L and 0.8 g/L in 0.15 M and 0.25 M H{sub 2}C{sub 2}O{sub 4}, respectively. The solubility of Gd at 8-10 M HNO{sub 3} exceeds the solubility at 6 M HNO{sub 3}. The data for 4 M HNO{sub 3} showed good agreement with data in the literature. To achieve a target of 6 g/L soluble Gd in solution in the presence of 0.15-0.25 M oxalate, the HNO{sub 3} concentration must be maintained at or above 6 M HNO{sub 3}. The solubility of Gd in 4 M HNO{sub 3} with 0.15 M oxalate at 10 °C is about 1.5 g/L. For 6 M HNO{sub 3} with 0.15 M oxalate, the solubility of Gd at 10

  5. Calcium Hydroxylapatite

    PubMed Central

    Yutskovskaya, Yana Alexandrovna; Philip Werschler, WM.

    2015-01-01

    Background: Calcium hydroxylapatite is one of the most well-studied dermal fillers worldwide and has been extensively used for the correction of moderate-to-severe facial lines and folds and to replenish lost volume. Objectives: To mark the milestone of 10 years of use in the aesthetic field, this review will consider the evolution of calcium hydroxylapatite in aesthetic medicine, provide a detailed injection protocol for a global facial approach, and examine how the unique properties of calcium hydroxylapatite provide it with an important place in today’s market. Methods: This article is an up-to-date review of calcium hydroxylapatite in aesthetic medicine along with procedures for its use, including a detailed injection protocol for a global facial approach by three expert injectors. Conclusion: Calcium hydroxylapatite is a very effective agent for many areas of facial soft tissue augmentation and is associated with a high and well-established safety profile. Calcium hydroxylapatite combines high elasticity and viscosity with an ability to induce long-term collagen formation making it an ideal agent for a global facial approach. PMID:25610523

  6. Calcium orthophosphates

    PubMed Central

    Dorozhkin, Sergey V.

    2011-01-01

    The present overview is intended to point the readers’ attention to the important subject of calcium orthophosphates. This type of materials is of special significance for human beings, because they represent the inorganic part of major normal (bones, teeth and antlers) and pathological (i.e., those appearing due to various diseases) calcified tissues of mammals. For example, atherosclerosis results in blood vessel blockage caused by a solid composite of cholesterol with calcium orthophosphates, while dental caries and osteoporosis mean a partial decalcification of teeth and bones, respectively, that results in replacement of a less soluble and harder biological apatite by more soluble and softer calcium hydrogenphosphates. Therefore, the processes of both normal and pathological calcifications are just an in vivo crystallization of calcium orthophosphates. Similarly, dental caries and osteoporosis might be considered an in vivo dissolution of calcium orthophosphates. Thus, calcium orthophosphates hold a great significance for humankind, and in this paper, an overview on the current knowledge on this subject is provided. PMID:23507744

  7. Ammonium reduces oxalate accumulation in different spinach (Spinacia oleracea L.) genotypes by inhibiting root uptake of nitrate.

    PubMed

    Liu, Xiaoxia; Lu, Lingli; Chen, Qiuhui; Ding, Wenya; Dai, Peibin; Hu, Yan; Yu, Yan; Jin, Chongwei; Lin, Xianyong

    2015-11-01

    Excessive accumulation of oxalate negatively affects nutritional value of many vegetables, such as spinach (Spinacia oleracea L.). Mixed solution of ammonium and nitrate could effectively reduce oxalate accumulation, while the mechanism involved remains unknown. High (Heizhenzhu) and low (Weilv) oxalate-accumulated spinach genotypes were used in this study to investigate the association of oxalate accumulation and root uptake of nitrogen. Exposure of increasing nitrate or mixed-nitrogen (nitrate:ammonium = 1:1) significantly increased leaf total and soluble oxalate contents. In contrast, increasing ammonium did not result in elevation of leaf oxalate. Correlation analysis confirmed that leaf oxalate accumulation was positively associated with root uptake of nitrate but not ammonium. Moreover, addition of ammonium significantly reduced nitrate uptake rate, and subsequently decreased leaf oxalate accumulation. The results suggest that oxalate synthesis in spinach leaves is associated with its root uptake of nitrate, and ammonium is able to reduce oxalate accumulation by inhibiting uptake of nitrate.

  8. Theoretical aspects of calcium signaling

    NASA Astrophysics Data System (ADS)

    Pencea, Corneliu Stefan

    2001-08-01

    Experiments investigating intracellular calcium dynamics have revealed that calcium signals differentially affect a variety of intracellular processes, from fertilization and cell development and differentiation to subsequent cellular activity, ending with cell death. As an intracellular messenger, calcium transmits information within and between cells, thus regulating their activity. To control such a variety of processes, calcium signals have to be very flexible and also precisely regulated. The cell uses a calcium signaling ``toolkit'', where calcium ions can act in different contexts of space, amplitude and time. For different tasks, the cell selects the particular signal, or combination of signals, that triggers the appropriate physiological response. The physical foundations of such a versatile cellular signaling toolkit involving calcium are not completely understood, despite important experimental and theoretical progress made recently. The declared goal of this work is to investigate physical mechanisms on which the propagation of differential signals can be based. The dynamics of calcium near a cluster of inositol trisphosphate (IP3) activated calcium channels has been investigated analytically and numerically. Our work has demonstrated that clusters of different IP3 receptors can show similar bistable behavior, but differ in both the transient and long term dynamics. We have also investigated the conditions under which a calcium signal propagates between a pair of localized stores. We have shown that the propagation of the signal across a random distribution of such stores shows a percolation transition manifested in the shape of the wave front. More importantly, our work indicates that specific distribution of stores can be interpreted as calcium circuits that can perform important signal analyzing task, from unidirectional propagation and coincidence detection to a complete set of logic gates. We believe that phenomena like the ones described are

  9. Effect of Dietary Oxalate on the Gut Microbiota of the Mammalian Herbivore Neotoma albigula

    PubMed Central

    Oakeson, Kelly F.; Dale, Colin; Dearing, M. Denise

    2016-01-01

    Diet is one of the primary drivers that sculpts the form and function of the mammalian gut microbiota. However, the enormous taxonomic and metabolic diversity held within the gut microbiota makes it difficult to isolate specific diet-microbe interactions. The objective of the current study was to elucidate interactions between the gut microbiota of the mammalian herbivore Neotoma albigula and dietary oxalate, a plant secondary compound (PSC) degraded exclusively by the gut microbiota. We quantified oxalate degradation in N. albigula fed increasing amounts of oxalate over time and tracked the response of the fecal microbiota using high-throughput sequencing. The amount of oxalate degraded in vivo was linearly correlated with the amount of oxalate consumed. The addition of dietary oxalate was found to impact microbial species diversity by increasing the representation of certain taxa, some of which are known to be capable of degrading oxalate (e.g., Oxalobacter spp.). Furthermore, the relative abundances of 117 operational taxonomic units (OTU) exhibited a significant correlation with oxalate consumption. The results of this study indicate that dietary oxalate induces complex interactions within the gut microbiota that include an increase in the relative abundance of a community of bacteria that may contribute either directly or indirectly to oxalate degradation in mammalian herbivores. PMID:26896138

  10. The Metabolic and Ecological Interactions of Oxalate-Degrading Bacteria in the Mammalian Gut

    PubMed Central

    Miller, Aaron W.; Dearing, Denise

    2013-01-01

    Oxalate-degrading bacteria comprise a functional group of microorganisms, commonly found in the gastrointestinal tract of mammals. Oxalate is a plant secondary compound (PSC) widely produced by all major taxa of plants and as a terminal metabolite by the mammalian liver. As a toxin, oxalate can have a significant impact on the health of mammals, including humans. Mammals do not have the enzymes required to metabolize oxalate and rely on their gut microbiota for this function. Thus, significant metabolic interactions between the mammalian host and a complex gut microbiota maintain the balance of oxalate in the body. Over a dozen species of gut bacteria are now known to degrade oxalate. This review focuses on the host-microbe and microbe-microbe interactions that regulate the degradation of oxalate by the gut microbiota. We discuss the pathways of oxalate throughout the body and the mammalian gut as a series of differentiated ecosystems that facilitate oxalate degradation. We also explore the mechanisms and functions of microbial oxalate degradation along with the implications for the ecological and evolutionary interactions within the microbiota and for mammalian hosts. Throughout, we consider questions that remain, as well as recent technological advances that can be employed to answer them. PMID:25437337

  11. Microbial Community Transplant Results in Increased and Long-Term Oxalate Degradation

    PubMed Central

    Miller, Aaron W.; Oakeson, Kelly F.; Dale, Colin; Dearing, M. Denise

    2016-01-01

    Gut microbes are essential for the degradation of dietary oxalate, and this function may play a role in decreasing the incidence of kidney stones. However, many oxalate-degrading bacteria are susceptible to antibiotics and the use of oxalate-degrading probiotics has only led to an ephemeral reduction in urinary oxalate. The objective of the current study was to determine the efficacy of using whole-community microbial transplants from a wild mammalian herbivore, Neotoma albigula, to increase oxalate degradation over the long term in the laboratory rat, Rattus norvegicus. We quantified the change in total oxalate degradation in lab rats immediately after microbial transplants and at 2- and 9-month intervals following microbial transplants. Additionally, we tracked the fecal microbiota of the lab rats, with and without microbial transplants, using high-throughput Illumina sequencing of a hyper-variable region of the 16S rRNA gene. Microbial transplants resulted in a significant increase in oxalate degradation, an effect that persisted 9 months after the initial transplants. Functional persistence was corroborated by the transfer, and persistence of a group of bacteria previously correlated with oxalate consumption in N. albigula, including an anaerobic bacterium from the genus Oxalobacter known for its ability to use oxalate as a sole carbon source. The results of this study indicate that whole-community microbial transplants are an effective means for the persistent colonization of oxalate-degrading bacteria in the mammalian gut. PMID:27312892

  12. Natural abiotic formation of oxalic acid in soils: results from aromatic model compounds and soil samples.

    PubMed

    Studenroth, Sabine; Huber, Stefan G; Kotte, Karsten; Schöler, Heinz F

    2013-02-05

    Oxalic acid is the smallest dicarboxylic acid and plays an important role in soil processes (e.g., mineral weathering and metal detoxification in plants). We have first proven its abiotic formation in soils and investigated natural abiotic degradation processes based on the oxidation of soil organic matter, enhanced by Fe(3+) and H(2)O(2) as hydroxyl radical suppliers. Experiments with the model compound catechol and further hydroxylated benzenes were performed to examine a common degradation pathway and to presume a general formation mechanism of oxalic acid. Two soil samples were tested for the release of oxalic acid and the potential effects of various soil parameters on oxalic acid formation. Additionally, the soil samples were treated with different soil sterilization methods to prove the oxalic acid formation under abiotic soil conditions. Different series of model experiments were conducted to determine a range of factors including Fe(3+), H(2)O(2), reaction time, pH, and chloride concentration on oxalic acid formation. Under certain conditions, catechol is degraded up to 65.6% to oxalic acid referring to carbon. In serial experiments with two soil samples, oxalic acid was produced, and the obtained results are suggestive of an abiotic degradation process. In conclusion, Fenton-like conditions with low Fe(3+) concentrations and an excess of H(2)O(2) as well as acidic conditions were required for an optimal oxalic acid formation. The presence of chloride reduced oxalic acid formation.

  13. Bis(tetra­ethyl­ammonium) oxalate dihydrate

    PubMed Central

    McNeese, Timothy J.; Pike, Robert D.

    2012-01-01

    The title compound, 2C8H20N+·C2O4 2−·2H2O, synthesized by neutralizing H2C2O4·2H2O with (C2H5)4NOH in a 1:2 molar ratio, is a deliquescent solid. The oxalate ion is nonplanar, with a dihedral angle between carboxyl­ate groups of 64.37 (2)°. O—H⋯O hydrogen bonds of moderate strength link the O atoms of the water mol­ecules and the oxalate ions into rings parallel to the c axis. The rings exhibit the graph-set motif R 4 4(12). In addition, there are weak C—H⋯O inter­actions in the crystal structure. PMID:22904842

  14. Purification of 238Pu Oxide using the Pu Oxalate Process

    SciTech Connect

    Mew, D A; Krikorian, O H; Dodson, K E; Schmitz, J A

    2001-11-28

    The Pu oxalate process is used to remove {sup 234}U from aged {sup 238}Pu-enriched PuO{sub 2} ({sup 234}U grows into the PuO{sub 2} material with time from a-decay of {sup 238}Pu). The Pu oxalate process was first used on a mixture of weapons grade PuO{sub 2} with UO{sub 2} to work out the processing parameters. It was then applied to aged {sup 238}Pu-enriched PuO{sub 2} ({sup 238}PuO{sub 2}). The {sup 234}U content of the {sup 238}PuO{sub 2} was reduced from 13.2 wt% to 0.0254 wt%, and the Pu recovery yield was 78.5%. The process is complex and is complicated by radiolysis problems when working with {sup 238}Pu. Details of the experiments are described.

  15. Isolation and characterizations of oxalate-binding proteins in the kidney

    SciTech Connect

    Roop-ngam, Piyachat; Chaiyarit, Sakdithep; Pongsakul, Nutkridta; Thongboonkerd, Visith

    2012-08-03

    Highlights: Black-Right-Pointing-Pointer The first large-scale characterizations of oxalate-binding kidney proteins. Black-Right-Pointing-Pointer The recently developed oxalate-conjugated EAH Sepharose 4B beads were applied. Black-Right-Pointing-Pointer 38 forms of 26 unique oxalate-binding kidney proteins were identified. Black-Right-Pointing-Pointer 25/26 (96%) of identified proteins had 'L-x(3,5)-R-x(2)-[AGILPV]' domain. -- Abstract: Oxalate-binding proteins are thought to serve as potential modulators of kidney stone formation. However, only few oxalate-binding proteins have been identified from previous studies. Our present study, therefore, aimed for large-scale identification of oxalate-binding proteins in porcine kidney using an oxalate-affinity column containing oxalate-conjugated EAH Sepharose 4B beads for purification followed by two-dimensional gel electrophoresis (2-DE) to resolve the recovered proteins. Comparing with those obtained from the controlled column containing uncoupled EAH-Sepharose 4B (to subtract the background of non-specific bindings), a total of 38 protein spots were defined as oxalate-binding proteins. These protein spots were successfully identified by quadrupole time-of-flight mass spectrometry (MS) and/or tandem MS (MS/MS) as 26 unique proteins, including several nuclear proteins, mitochondrial proteins, oxidative stress regulatory proteins, metabolic enzymes and others. Identification of oxalate-binding domain using the PRATT tool revealed 'L-x(3,5)-R-x(2)-[AGILPV]' as a functional domain responsible for oxalate-binding in 25 of 26 (96%) unique identified proteins. We report herein, for the first time, large-scale identification and characterizations of oxalate-binding proteins in the kidney. The presence of positively charged arginine residue in the middle of this functional domain suggested its significance for binding to the negatively charged oxalate. These data will enhance future stone research, particularly on stone

  16. Effect of Macerase, Oxalic Acid, and EGTA on Deep Supercooling and Pit Membrane Structure of Xylem Parenchyma of Peach

    PubMed Central

    Wisniewski, Michael; Davis, Glen; Arora, Rajeev

    1991-01-01

    The object of this study was to determine if calcium cross-linking of pectin in the pit membrane of xylem parenchyma restricts water movement which results in deep supercooling. Current year shoots of `Loring' peach (Prunus persica) were infiltrated with oxalic acid or EGTA solutions for 24 or 48 hours and then either prepared for ultrastructural analysis or subjected to differential thermal analysis. The effect of 0.25 to 1.0% pectinase (weight/volume) on deep supercooling was also investigated. The use of 5 to 50 millimolar oxalic acid and pectinase resulted in a significant reduction (flattening) of the low temperature exotherm and a distinct swelling and partial degradation of the pit membrane. EGTA (10 millimolar) for 24 or 48 hours shifted the low temperature exotherm to warmer temperatures and effected the outermost layer of the pit membrane. A hypothesis is presented on pectin-mediated regulation of deep supercooling of xylem parenchyma. ImagesFigure 3Figure 4Figure 5Figure 6Figure 7Figure 8 PMID:16668341

  17. Equilibrium studies of oxalate and aluminum containing solutions

    SciTech Connect

    Hay, M. S.; King, W. D.; Peters, T. B.; Jones, D. H.

    2015-11-01

    The Savannah River National Laboratory (SRNL) was tasked to develop data on the solubility and conditions leading to precipitation of sodium oxalate, sodium nitrate, Bayerite (a polymorph of gibbsite, Al(OH)3), and sodium aluminosilicate solids recently found in the Modular Caustic Side Solvent Extraction Unit (MCU). The data generated will be used to improve the OLI Systems thermodynamic database for these compounds allowing better prediction of solids formation by the modeling software in the future.

  18. Oxalate oxidases and differentiating surface structure in wheat: germins.

    PubMed Central

    Lane, B G

    2000-01-01

    Oxalate oxidases (OXOs) have been found to be concentrated in the surface tissues of wheat embryos and grains: germin is concentrated in root and leaf sheaths that surround germinated embryos; pseudogermin (OXO-psi) is concentrated in the epidermis and bracts that 'encircle' mature grains. Most strikingly, the epidermal accumulation of OXO-psi was found to presage the transition of a delicate 'skin', similar to the fragile epidermis of human skin, into the tough shell (the miller's 'beeswing') that is typical of mature wheat grains. A narrow range of oxalate concentration (1--2 mM) in the hydrated tissues of major crop cereals (barley, maize, oat, rice, rye and wheat) contrasted with wide variations in their OXO expression, e.g. cold-tolerant and cold-sensitive varieties of maize have similar oxalate contents but the former was found to contain approx. 20-fold more germin than did the latter. Well-known OXOs in sorghum, a minor cereal, and beet, a dicotyledon, were found to have little antigenic relatedness to the germins, but the beet enzyme did share some of the unique stability properties that are peculiar to the germin-like OXOs that are found only in the major crop cereals. Their concentration in surface structures of domesticated wheat suggests a biochemical role for germin-like OXOs: programmed cell death in surface tissues might be a constitutive as well as an adaptive form of differentiation that helps to produce refractory barriers against tissue invasion by predators. Incidental to the principal investigation, and using an OXO assay (oxalate-dependent release of CO(2)) that did not rely on detecting H(2)O(2), which is often fully degraded in cell extracts, it was found that OXO activity in soluble extracts of wheat was manifested only in standard solution assays if the extract was pretreated in a variety of ways, which included preincubation with pepsin or highly substituted glucuronogalactoarabinoxylans (cell-wall polysaccharides). PMID:10861243

  19. Autogenous vein graft thrombosis following exposure to calcium-free solutions (calcium paradox).

    PubMed

    Nozick, J H; Farnsworth, P; Montefusco, C M; Parsonnet, V; Ruigrok, T J; Zimmerman, A N

    1981-01-01

    The morphological and functional effects of calcium-free and calcium-containing solutions on canine jugular vein intima were examined under conditions which closely resemble those techniques currently employed in peripheral vascular and aortocoronary bypass surgery. Veins that had been exposed only to calcium-containing solutions remained patent for the duration of the experimental period. Vein perfusion with a calcium-free solution, however, resulted in disruption of the jugular vein intima once calcium ions were reintroduced. Autogenous as a femoral arterial graft became thrombosed within 60 minutes. It is therefore suggested that vein grafts of autogenous origin be irrigated with calcium-containing solutions to prevent intimal damage and thrombosis.

  20. Some acid-base balance-dependent urinary parameters and calcium-binding anions in stone formers.

    PubMed

    Vogel, E; Leskovar, P; Schütz, W

    1984-01-01

    Urinary organic acids were determined by gradual titration of portioned urine samples of moderately and severely recurrent stone patients and compared to those found in healthy controls. An essential deficit of organic acids was found in patients with a high recurrence rate. According to the results, the lack of organic acids in the urine of urolithiasis patients, accompanied by a reduced inhibition of the calcium-oxalate and calcium-phosphate crystallization might be causatively involved in the stone formation.

  1. Pseudomonas fluorescens ATCC 13525 containing an artificial oxalate operon and Vitreoscilla hemoglobin secretes oxalic acid and solubilizes rock phosphate in acidic alfisols.

    PubMed

    Yadav, Kavita; Kumar, Chanchal; Archana, G; Naresh Kumar, G

    2014-01-01

    Oxalate secretion was achieved in Pseudomonas fluorescens ATCC 13525 by incorporation of genes encoding Aspergillus niger oxaloacetate acetyl hydrolase (oah), Fomitopsis plaustris oxalate transporter (FpOAR) and Vitreoscilla hemoglobin (vgb) in various combinations. Pf (pKCN2) transformant containing oah alone accumulated 19 mM oxalic acid intracellularly but secreted 1.2 mM. However, in the presence of an artificial oxalate operon containing oah and FpOAR genes in plasmid pKCN4, Pf (pKCN4) secreted 13.6 mM oxalate in the medium while 3.6 mM remained inside. This transformant solubilized 509 μM of phosphorus from rock phosphate in alfisol which is 4.5 fold higher than the Pf (pKCN2) transformant. Genomic integrants of P. fluorescens (Pf int1 and Pf int2) containing artificial oxalate operon (plac-FpOAR-oah) and artificial oxalate gene cluster (plac-FpOAR-oah, vgb, egfp) secreted 4.8 mM and 5.4 mM oxalic acid, released 329 μM and 351 μM P, respectively, in alfisol. The integrants showed enhanced root colonization, improved growth and increased P content of Vigna radiata plants. This study demonstrates oxalic acid secretion in P. fluorescens by incorporation of an artificial operon constituted of genes for oxalate synthesis and transport, which imparts mineral phosphate solubilizing ability to the organism leading to enhanced growth and P content of V. radiata in alfisol soil.

  2. Antioxidant Pre-Treatment Reduces the Toxic Effects of Oxalate on Renal Epithelial Cells in a Cell Culture Model of Urolithiasis

    PubMed Central

    Kizivat, Tomislav; Smolić, Martina; Marić, Ivana; Tolušić Levak, Maja; Smolić, Robert; Bilić Čurčić, Ines; Kuna, Lucija; Mihaljević, Ivan; Včev, Aleksandar; Tucak-Zorić, Sandra

    2017-01-01

    Urolithiasis is characterized by the formation and retention of solid crystals within the urinary tract. Kidney stones are mostly composed of calcium oxalate, which predominantly generates free radicals that are toxic to renal tubular cells. The aim of the study is to explore possible effects of antioxidant pre-treatment on inhibition of oxidative stress. Three cell lines were used as in vitro model of urolithiasis: MDCK I, MDCK II and LLC-PK1. Oxidative stress was induced by exposure of cells to sodium oxalate in concentration of 8 mM. In order to prevent oxidative stress, cells were pre-treated with three different concentrations of l-arginine and vitamin E. Oxidative stress was evaluated by determining the expression of superoxide dismutase (SOD), osteopontin (OPN), and by the concentration of glutathione (GSH). In all three cell lines, pre-treatment of antioxidants increased cell survival. Positive correlation of SOD and OPN expression as well as GSH concentration was observed in all groups of cells. Our results indicate that an antioxidant pre-treatment with l-arginine and vitamin E is able to hamper oxalate-induced oxidative stress in kidney epithelial cells and as such could play a role in prevention of urolithiasis. PMID:28125004

  3. Novel Peptide with Specific Calcium-Binding Capacity from Schizochytrium sp. Protein Hydrolysates and Calcium Bioavailability in Caco-2 Cells

    PubMed Central

    Cai, Xixi; Lin, Jiaping; Wang, Shaoyun

    2016-01-01

    Peptide-calcium can probably be a suitable supplement to improve calcium absorption in the human body. In this study, a specific peptide Phe-Tyr (FY) with calcium-binding capacity was purified from Schizochytrium sp. protein hydrolysates through gel filtration chromatography and reversed phase HPLC. The calcium-binding capacity of FY reached 128.77 ± 2.57 μg/mg. Results of ultraviolet spectroscopy, fluorescence spectroscopy, and infrared spectroscopy showed that carboxyl groups, amino groups, and amido groups were the major chelating sites. FY-Ca exhibited excellent thermal stability and solubility, which were beneficial to be absorbed and transported in the basic intestinal tract of the human body. Moreover, the calcium bioavailability in Caco-2 cells showed that FY-Ca could enhance calcium uptake efficiency by more than three times when compared with CaCl2, and protect calcium ions against dietary inhibitors, such as tannic acid, oxalate, phytate, and Zn2+. Our findings further the progress of algae-based peptide-calcium, suggesting that FY-Ca has the potential to be developed as functionally nutraceutical additives. PMID:28036002

  4. Evidence for a cytoplasmic pathway of oxalate biosynthesis in Aspergillus niger.

    PubMed Central

    Kubicek, C P; Schreferl-Kunar, G; Wöhrer, W; Röhr, M

    1988-01-01

    Oxalate accumulation of up to 8 g/liter was induced in Aspergillus niger by shifting the pH from 6 to 8. This required the presence of Pi and a nitrogen source and was inhibited by the protein synthesis inhibitor cycloheximide. Exogenously added 14CO2 was not incorporated into oxalate, but was incorporated into acetate and malate, thus indicating the biosynthesis of oxalate by hydrolytic cleavage of oxaloacetate. Inhibition of mitochondrial citrate metabolism by fluorocitrate did not significantly decrease the oxalate yield. The putative enzyme that was responsible for this was oxaloacetate hydrolase (EC 3.7.1.1), which was induced de novo during the pH shift. Subcellular fractionation of oxalic acid-forming mycelia of A. niger showed that this enzyme is located in the cytoplasm of A. niger. The results are consistent with a cytoplasmic pathway of oxalate formation which does not involve the tricarboxylic acid cycle. PMID:3132096

  5. Calcium homeostasis in diabetes mellitus.

    PubMed

    Heath, H; Lambert, P W; Service, F J; Arnaud, S B

    1979-09-01

    Experimentally diabetic rats have low serum 1,25-dihydroxyvitamin D, intestinal malabsorption of calcium, secondary hyperparathyroidism, and bone loss. To examine the hypothesis that abnormalities similar to those in the diabetic rat might explain human diabetic osteopenia, we studied calcium metabolism in 40 healthy control and 82 diabetic patients aged 18--75 yr [47 untreated: fasting plasma glucose (mean +/- SE), 267 +/- 8 mg/dl; 19 treated but hyperglycemic: glucose 305 +/- 24 mg/dl; 16 treated and in better control: glucose, 146 +/- 8 mg/dl]. Serum total calcium, ionic calcium, immunoreactive parathyroid hormone (Arnaud method, GP-1M and CH-12M antisera), 25-hydroxyvitamin D (Haddad method), and 1,25-dihydroxyvitamin D (Lambert method) concentrations were normal in all 3 groups of diabetics and were not significantly different from values in the control group. We determined absorption of calcium from the intestine by a double isotope method (100 mg Ca carrier; normal range, 40--80%) in 11 control and 13 untreated, uncontrolled diabetics (mean plasma glucose, 285 +/- 17 mg/dl). Absorption of calcium in controls was 60 +/- 3% and in diabetics was 56 +/- 3% (not significantly different). We have found no derangement of calcium metabolism in adults with insulin-requiring juvenile- and adult-onset diabetes regardless of treatment status. The experimental diabetic rat model does not appear to be useful for determining the pathogenesis of adult human diabetic osteopenia.

  6. Field Assessment of Yeast- and Oxalic Acid-generated Carbon Dioxide for Mosquito Surveillance

    DTIC Science & Technology

    2014-12-01

    FIELD ASSESSMENT OF YEAST- AND OXALIC ACID –GENERATED CARBON DIOXIDE FOR MOSQUITO SURVEILLANCE1 JAMES F. HARWOOD, ALEC G. RICHARDSON, JENNIFER A...were evaluated in order to address this capability gap: 1) an electrolyzer that converts solid oxalic acid into CO2 gas, and 2) CO2 produced by yeast...surveillance was compared to dry ice and compressed gas in Jacksonville, FL. The electrolyzed oxalic acid only slightly increased the number of

  7. Calcium Test

    MedlinePlus

    ... if a person has symptoms of a parathyroid disorder , malabsorption , or an overactive thyroid. A total calcium level is often measured as part of a routine health screening. It is included in the comprehensive metabolic panel (CMP) and the basic metabolic panel (BMP) , ...

  8. Calcium cyanide

    Integrated Risk Information System (IRIS)

    Jump to main content . Integrated Risk Information System Recent Additions | Contact Us Search : All EPA IRIS • You are here : EPA Home • Research • Environmental Assessment • IRIS • IRIS Summaries Redirect Page As of September 28 , 2010 , the assessment summary for calcium cyanide is included in th

  9. Rare calcium oxalate monohydrate calculus attached to the wall of the renal pelvis.

    PubMed

    Grases, Felix; Costa-Bauza, Antonia; Prieto, Rafael M; Saus, Carlos; Servera, Antonio; García-Miralles, Reyes; Benejam, Joan

    2011-04-01

    Most renal calculi can be classified using well-established criteria in a manner that reflects both composition and fine structure under specific pathophysiological conditions. However, when a large patient population is considered, rare renal calculi invariably appear, some of which have never been classified; careful study is required to establish stone etiology in such cases. The patient in the present case report formed two types of calculi. One was attached on the wall of the renal pelvis near the ureter and part of the calculus was embedded inside pelvic renal tissue. The calculus developed on an ossified calcification located in the pelvis tissue. Current knowledge on the development of calcification in soft tissues suggests a pre-existing injury as an inducer of its development. A mechanism of calculus formation is proposed. The second stone was a typical jack-stone calculus.

  10. Some measurements of calcium oxalate nucleation and growth rates in urine-like liquors

    NASA Astrophysics Data System (ADS)

    Randolph, A. D.; Drach, G. W.

    1981-05-01

    Development of the MSMPR crystallizer for study of CaOx crystallization kinetics was traced from its beginning to current versions having in situ particle size measurements with on-line minicomputer data regression. MSMPR studies of COD crystallization kinetics in a synthetic urine liqour, with or without a component of human urine, were summarized. These results were extended by the data of this study which show the effects of osmolarity, Ox feed concentration, urea and magnesium as they effect COD nucleation and growth rates. Although consistent variations in COD crystallization kinetics were observed with the above variables, such variations (with the exception of Ox in feed) are small compared with effects due to urinary macromolecules.

  11. The effects of oxalate treatment on the smear layer of ground surfaces of human dentine.

    PubMed

    Pashley, D H; Galloway, S E

    1985-01-01

    The layer was evaluated by scanning electron microscopy and by measurement of hydraulic conductance before and after 2-min topical treatment with potassium chloride, neutral potassium oxalate, half-neutralized oxalic acid or both neutral and acidic oxalates. The treated smear layers were then re-evaluated microscopically and functionally both before and after acid challenge. The layers treated with KCl were not altered either microscopically or functionally and were susceptible to acid etching. Dentine surfaces treated with either oxalate solutions became less permeable and were acid-resistant.

  12. Old acid, new chemistry. Negative metal anions generated from alkali metal oxalates and others.

    PubMed

    Curtis, Sharon; Renaud, Justin; Holmes, John L; Mayer, Paul M

    2010-11-01

    A brief search in Sci Finder for oxalic acid and oxalates will reward the researcher with a staggering 129,280 hits. However, the generation of alkali metal and silver anions via collision-induced dissociation of the metal oxalate anion has not been previously been reported, though Tian and coworkers recently investigated the dissociation of lithium oxalate. The exothermic decomposition of alkali metal oxalate anion to carbon dioxide in the collision cell of a triple quadrupole mass spectrometer leaves no place for the electron to reside, resulting in a double electron-transfer reaction to produce an alkali metal anion. This reaction is facilitated by the negative electron affinity of carbon dioxide and, as such, the authors believe that metal oxalates are potentially unique in this respect. The observed dissociation reactions for collision with argon gas (1.7-1.8 × 10(-3) mbar) for oxalic acid and various alkali metal oxalates are discussed and summarized. Silver oxalate is also included to demonstrate the propensity of this system to generate transition-metal anions, as well.

  13. Availability to rats of iron from spinach: Effects of oxalic acid.

    PubMed

    Van Campen, D R; Welch, R M

    1980-08-01

    The availability to rats of iron from two varieties of spinach was determined. Also, the absorption of Fe was compared between FeCl3 and Fe-oxalate and the effects of adding 0.75% oxalate to the diet were determined. Absorption of iron from both varieties of spinach was comparable to that from FeCl3 and the iron was equally available from Fe-oxalate and FeCl3. The addition of 0.75% oxalic acid to the diet did not depress iron absorption and, if anything, appeared to enhance iron utilization by rats.

  14. Effects of oxalate on IMCD cells: a line of mouse inner medullary collecting duct cells.

    PubMed

    Maroni, Paul D; Koul, Sweaty; Meacham, Randall B; Chandhoke, Paramjit S; Koul, Hari K

    2004-12-01

    Oxalate, a metabolic end product and a major constituent of the majority of renal stones, has been shown to be toxic to renal epithelial cells of cortical origin. However, it is unknown whether inner medullary collecting duct (IMCD) cells that are physiologically exposed to higher concentrations of oxalate also behave in a similar manner. In the present study, we examined the effects of oxalate on IMCD cells. IMCD cells from the mouse were maintained in DMEM/F12 media supplemented with fetal bovine serum and antibiotics. Exposure of IMCD cells to oxalate produced time- and concentration-dependent changes in the light microscopic appearance of the cells. Long-term exposure to oxalate resulted in alterations in cell viability, with net cell loss after exposure to concentrations of 2 mM or greater. The production of free radicals was directly related to the exposure time and the concentration of oxalate. Crystal formation occurred in less than 1 h and cells in proximity to crystals would lose membrane integrity. Compared with IMCD cells, LLC-PK1 cells as well as HK-2 cells showed significant toxicity starting at lower oxalate concentrations (0.4 mM or greater). These results provide the first direct demonstration of toxic effects of oxalate in IMCD cells, a line of renal epithelial cells of the inner medullary collecting duct, and suggest that the cells lining the collecting duct are relatively resistant to oxalate toxicity.

  15. Identification and characterization of oxalate oxidoreductase, a novel thiamine pyrophosphate-dependent 2-oxoacid oxidoreductase that enables anaerobic growth on oxalate.

    PubMed

    Pierce, Elizabeth; Becker, Donald F; Ragsdale, Stephen W

    2010-12-24

    Moorella thermoacetica is an anaerobic acetogen, a class of bacteria that is found in the soil, the animal gastrointestinal tract, and the rumen. This organism engages the Wood-Ljungdahl pathway of anaerobic CO(2) fixation for heterotrophic or autotrophic growth. This paper describes a novel enzyme, oxalate oxidoreductase (OOR), that enables M. thermoacetica to grow on oxalate, which is produced in soil and is a common component of kidney stones. Exposure to oxalate leads to the induction of three proteins that are subunits of OOR, which oxidizes oxalate coupled to the production of two electrons and CO(2) or bicarbonate. Like other members of the 2-oxoacid:ferredoxin oxidoreductase family, OOR contains thiamine pyrophosphate and three [Fe(4)S(4)] clusters. However, unlike previously characterized members of this family, OOR does not use coenzyme A as a substrate. Oxalate is oxidized with a k(cat) of 0.09 s(-1) and a K(m) of 58 μM at pH 8. OOR also oxidizes a few other 2-oxoacids (which do not induce OOR) also without any requirement for CoA. The enzyme transfers its reducing equivalents to a broad range of electron acceptors, including ferredoxin and the nickel-dependent carbon monoxide dehydrogenase. In conjunction with the well characterized Wood-Ljungdahl pathway, OOR should be sufficient for oxalate metabolism by M. thermoacetica, and it constitutes a novel pathway for oxalate metabolism.

  16. The Influence of Dentine on the pH of Calcium Hydroxide, Chlorhexidine Gel, and Experimental Bioactive Glass-Based Root Canal Medicament

    PubMed Central

    Nunes Carvalho, Ceci; Gonzales Freire, Laila; Pinheiro Lima de Carvalho, Alexandre; Luiz Siqueira, Evandro; Bauer, José; Cunha Gritti, Giovana; Pereira de Souza, Juliana; Gavini, Giulio

    2015-01-01

    Objectives. To evaluate the influence of dentine on the pH of different medications in standardized simulated canals. Materials and Methods. Forty resin blocks were divided into groups with and without dentine powder, as follows: 2% chlorhexidine gel; 2% chlorhexidine gel associated with calcium hydroxide PA; calcium hydroxide PA delivered in propylene glycol 600; and NPG delivered in distilled water. The dentine powder was obtained from the root dentine of bovine teeth and added to the medications. The simulated canals were placed in containers with 1.5 mL of deionized water and pH was monitored in multiple intervals, up to 30 days. The mean pH values were calculated and submitted to statistical analysis using paired Student's t-test and ANOVA complemented by the Tukey test (p < 0.05). Results. There was no statistical difference between the groups with and without dentine powder (p > 0.05). The pH values of calcium hydroxide were significantly higher than those of NPG in the first 24 hours (p < 0.05). After 7 days, both behaved in a similar manner. Conclusion. The addition of dentine powder to the medications evaluated did not alter the pH of the external solution in any of the time points tested. PMID:26347249

  17. Acute calcium homeostasis in MHS swine.

    PubMed

    Harrison, G G; Morrell, D F; Brain, V; Jaros, G G

    1987-07-01

    To elucidate a pathogenesis for the reduction in bone calcium content observed in MHS individuals, we studied the acute calcium homeostasis of MHS swine. This was achieved by the serial measurement, with a calcium selective electrode, of calcium transients in Landrace MHS (five) and control Landrace/large white cross MH negative (five) swine following IV bolus injection of calcium gluconate 0.1 mmol X kg-1--a dose which induced an acute 45 per cent increase in plasma ionised calcium. Experimental animals were anaesthetised with ketamine 10 mg X kg-1 IM, thiopentone (intermittent divided doses) 15-25 mg X kg-1 (total) IV and N2O/O2 (FIO2 0.3) by IPPV to maintain a normal blood gas, acid/base state. The plasma ionised calcium decay curve observed in MHS swine did not differ from that of control normal swine. Further it was noted that the induced acute rise in plasma ionised calcium failed to trigger the MH syndrome in any MHS swine. It is concluded that the mechanisms of acute calcium homeostasis in MHS swine are normal. An explanation for the reduction in bone calcium content observed in MHS individuals must be sought, therefore, through study of the slow long-term component of the calcium regulatory process. In addition, the conventional strictures placed on the use, in MHS patients, of calcium gluconate are called in question.

  18. Study on the Equilibrium Between Liquid Iron and Calcium Vapor

    NASA Astrophysics Data System (ADS)

    Berg, Martin; Lee, Jaewoo; Sichen, Du

    2017-02-01

    The solubility of calcium in liquid iron at 1823 K and 1873 K (1550 °C and 1600 °C) as a function of calcium potential was studied experimentally. The measurements were performed using a closed molybdenum holder in which liquid calcium and liquid iron were held at different temperatures. The results indicate a linear relationship between the activity of calcium, relative to pure liquid calcium, and the mole fraction of dissolved calcium in liquid iron, with a negligible temperature dependency in the ranges studied. The activity coefficient of calcium in liquid iron at infinite dilution, γ_{Ca}({l}^°, was calculated as 1551.

  19. Concentration and size distribution of particulate oxalate in marine and coastal atmospheres - Implication for the increased importance of oxalate in nanometer atmospheric particles

    NASA Astrophysics Data System (ADS)

    Guo, Tianfeng; Li, Kai; Zhu, Yujiao; Gao, Huiwang; Yao, Xiaohong

    2016-10-01

    In literature, particulate oxalate has been widely studied in the total suspended particles (TSP), particles <10 μm or 2.5 μm (PM10 and PM2.5) and size-segregated particles >100 nm. In this article, we measured oxalate's concentrations in size-segregated atmospheric particles down to 10 nm or 56 nm during eight campaigns performed at a semi-urban coastal site, over the marginal seas of China and from the marginal seas to the northwest Pacific Ocean (NWPO) in 2012-2015. When the sum of the oxalate's concentration in particles <10 μm was used for intercomparison, the lowest average values of 0.05-0.06 μg m-3 were observed during the two campaigns performed at NWPO. The highest average value of 0.38 μg m-3 was observed at the coastal site during a heavy pollution event. Mode analysis results of particulate oxalate and the correlation between oxalate and sulfate suggested that the elevated concentrations of oxalate in PM10 were mainly related to enhanced in-cloud formation of oxalate via anthropogenic precursors. Size distribution data in the total of 136 sets of samples also showed approximately 80% of particulate oxalate's mass existing in atmospheric particles >100 nm. Consistent with previous studies, particulate oxalate in particles >100 nm was a negligible ionic component when comparing to particulate SO42- in the same size range. However, the mole ratios of oxalate/sulfate in particles <100 nm were generally increased by 1-2 orders of magnitude. In approximately 30% of the samples, the mole ratios in atmospheric particles <56 nm were larger than 0.5. Moreover, during Campaign 5, the oxalate's concentrations in <56 nm particles were substantially increased on the days in presence of new particle formation events. These results strongly imply the importance of oxalate in nanometer atmospheric particles, but not in >100 nm atmospheric particles such as PM2.5, PM10, TSP, etc.

  20. Metal oxyhydroxide dissolution as promoted by structurally diverse siderophores and oxalate

    NASA Astrophysics Data System (ADS)

    Akafia, Martin M.; Harrington, James M.; Bargar, John R.; Duckworth, Owen W.

    2014-09-01

    Siderophores, a class of biogenic ligands with high affinities for Fe(III), promote the dissolution of metal ions from sparingly soluble mineral phases. However, most geochemical studies have focused on quantifying the reactivity of DFOB, a model trishydroxamate siderophore. This study utilized three different siderophores, desferrioxamine B, rhizoferrin, and protochelin, with structures that contain the most commonly observed binding moieties of microbial siderophores to examine the siderophore-promoted dissolution rates of FeOOH, CoOOH, and MnOOH in the absence and presence of the ubiquitous low molecular mass organic acid oxalate by utilizing batch dissolution experiments at pH = 5-9. Metal-siderophore complex and total dissolved metal concentrations were monitored for durations of one hour to fourteen days, depending on the metal oxyhydroxide identity and solution pH. The results demonstrate that MnOOH and CoOOH generally dissolve more quickly in the presence of siderophores than FeOOH. Whereas FeOOH dissolved exclusively by a ligand-promoted dissolution mechanism, MnOOH and CoOOH dissolved predominantly by a reductive dissolution mechanism under most experimental conditions. For FeOOH, siderophore-promoted dissolution rates trended with the stability constant of the corresponding aqueous Fe(III) complex. In the presence of oxalate, measured siderophore-promoted dissolution rates were found to increase, decrease, or remain unchanged as compared to the observed rates in single-ligand systems, depending on the pH of the system, the siderophore present, and the identity of the metal oxyhydroxide. Increases in observed dissolution rates in the presence of oxalate were generally greater for FeOOH than for MnOOH or CoOOH. These results elucidate potential dissolution mechanisms of both ferric and non-ferric oxyhydroxide minerals by siderophores in the environment, and may provide further insights into the biological strategies of metal acquisition facilitated by

  1. Solubility of Plutonium (IV) Oxalate During Americium/Curium Pretreatment

    SciTech Connect

    Rudisill, T.S.

    1999-08-11

    Approximately 15,000 L of solution containing isotopes of americium and curium (Am/Cm) will undergo stabilization by vitrification at the Savannah River Site (SRS). Prior to vitrification, an in-tank pretreatment will be used to remove metal impurities from the solution using an oxalate precipitation process. Material balance calculations for this process, based on solubility data in pure nitric acid, predict approximately 80 percent of the plutonium in the solution will be lost to waste. Due to the uncertainty associated with the plutonium losses during processing, solubility experiments were performed to measure the recovery of plutonium during pretreatment and a subsequent precipitation process to prepare a slurry feed for a batch melter. A good estimate of the plutonium content of the glass is required for planning the shipment of the vitrified Am/Cm product to Oak Ridge National Laboratory (ORNL).The plutonium solubility in the oxalate precipitation supernate during pretreatment was 10 mg/mL at 35 degrees C. In two subsequent washes with a 0.25M oxalic acid/0.5M nitric acid solution, the solubility dropped to less than 5 mg/mL. During the precipitation and washing steps, lanthanide fission products in the solution were mostly insoluble. Uranium, and alkali, alkaline earth, and transition metal impurities were soluble as expected. An elemental material balance for plutonium showed that greater than 94 percent of the plutonium was recovered in the dissolved precipitate. The recovery of the lanthanide elements was generally 94 percent or higher except for the more soluble lanthanum. The recovery of soluble metal impurities from the precipitate slurry ranged from 15 to 22 percent. Theoretically, 16 percent of the soluble oxalates should have been present in the dissolved slurry based on the dilution effects and volumes of supernate and wash solutions removed. A trace level material balance showed greater than 97 percent recovery of americium-241 (from the beta dec

  2. Calcium and bone disease

    PubMed Central

    Blair, Harry C.; Robinson, Lisa J.; Huang, Christopher L.-H.; Sun, Li; Friedman, Peter A.; Schlesinger, Paul H.; Zaidi, Mone

    2013-01-01

    Calcium transport and calcium signaling are of basic importance in bone cells. Bone is the major store of calcium and a key regulatory organ for calcium homeostasis. Bone, in major part, responds to calcium-dependent signals from the parathyroids and via vitamin D metabolites, although bone retains direct response to extracellular calcium if parathyroid regulation is lost. Improved understanding of calcium transporters and calcium-regulated cellular processes has resulted from analysis of genetic defects, including several defects with low or high bone mass. Osteoblasts deposit calcium by mechanisms including phosphate and calcium transport with alkalinization to absorb acid created by mineral deposition; cartilage calcium mineralization occurs by passive diffusion and phosphate production. Calcium mobilization by osteoclasts is mediated by acid secretion. Both bone forming and bone resorbing cells use calcium signals as regulators of differentiation and activity. This has been studied in more detail in osteoclasts, where both osteoclast differentiation and motility are regulated by calcium. PMID:21674636

  3. Contrasting calcium localization and speciation in leaves of Medicago truncatula mutant COD5 analyzed via synchrotron X-ray techniques

    PubMed Central

    Punshon, Tracy; Tappero, Ryan; Ricachenevsky, Felipe K.; Hirschi, Kendal; Nakata, Paul A.

    2014-01-01

    SUMMARY Oxalate-producing plants accumulate calcium oxalate crystals (CaOx(c)) in the range of 3–80%(w/w) of their dry weight, reducing calcium (Ca) bioavailability. The calcium oxalate deficient 5 (cod5) mutant of Medicago truncatula has been previously shown to contain similar Ca, but lower oxalate and CaOx(c) concentrations than wild type (WT) plants. We imaged the Ca distribution in WT and cod5 leaflets via synchrotron X-ray fluorescence mapping (SXRF). We observed a contrast in the Ca distribution between cod5 and WT leaflets, manifested as an abundance of Ca in the interveinal areas and a lack of Ca along the secondary veins in cod5, the opposite of WT. X-ray microdiffraction (µXRD) of M. truncatula leaves confirmed crystalline CaOx(c) (whewellite; CaC2O4•H2O) was present in WT only, in cells sheathing the secondary veins. Together with µXRD, microbeam Ca K-edge X-ray absorption near-edge structure spectroscopy (µXANES) indicated that among the forms of CaOx – namely crystalline or amorphous – only amorphous CaOx was present in cod5. These results demonstrate that deletion of COD5 changes both Ca localization and the form of CaOx within leaflets. PMID:24033783

  4. Catalytic kinetic spectrophotometry for the determination of trace amount of oxalic acid in biological samples with oxalic acid-rhodamine B-potassium dichromate system

    NASA Astrophysics Data System (ADS)

    Zhai, Qing-Zhou; Zhang, Xiao-Xia; Liu, Qing-Zhou

    2006-09-01

    A new catalytic kinetic spectrophotometric method was proposed for determining trace oxalic acid based on the catalytic effect of oxalate on the oxidation of potassium dichromate with rhodamin B in 0.10 M of sulfuric acid. Good linearity is obtained over the concentration range 0.40-6.0 μg/mL of oxalic acid. After the reactions of the catalytic and non-catalytic systems were terminated by using 2.00 mL of 4 M sodium hydroxide solution, they can be stable for 3 h at room temperature. The apparent activation energy of the catalytic reaction is 12.44 kJ/mol. The effect of 50 coexisting substances was observed. The method was used to determine trace oxalic acid in tea, spinach and urine samples with satisfactory results.

  5. Catalytic kinetic spectrophotometry for the determination of trace amount of oxalic acid in biological samples with oxalic acid-rhodamine B-potassium dichromate system.

    PubMed

    Zhai, Qing-Zhou; Zhang, Xiao-Xia; Liu, Qing-Zhou

    2006-09-01

    A new catalytic kinetic spectrophotometric method was proposed for determining trace oxalic acid based on the catalytic effect of oxalate on the oxidation of potassium dichromate with rhodamin B in 0.10 M of sulfuric acid. Good linearity is obtained over the concentration range 0.40-6.0 microg/mL of oxalic acid. After the reactions of the catalytic and non-catalytic systems were terminated by using 2.00 mL of 4 M sodium hydroxide solution, they can be stable for 3 h at room temperature. The apparent activation energy of the catalytic reaction is 12.44 kJ/mol. The effect of 50 coexisting substances was observed. The method was used to determine trace oxalic acid in tea, spinach and urine samples with satisfactory results.

  6. Oxalic acid biosynthesis is encoded by an operon in Burkholderia glumae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although the biosynthesis of oxalic acid is known to occur in a number of bacteria, the mechanism(s) regulating its production remains largely unknown. To date, there is no report on the identification of an oxalic acid biosynthetic pathway gene from bacteria. In an attempt to identify such a gene...

  7. An oxalyl-CoA synthetase is important for oxalate metabolism in Saccharomyces cerevisiae

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although oxalic acid is common in nature, our understanding of the mechanism(s) regulating its turnover remains incomplete. In this study we identify Saccharomyces cerevisiae acyl-activating enzyme 3 (ScAAE3) as an enzyme capable of catalyzing the conversion of oxalate to oxalyl-CoA. Based on our fi...

  8. Complete genome sequence of oxalate-degrading bacterium Pandoraea vervacti DSM 23571(T).

    PubMed

    Ee, Robson; Yong, Delicia; Lim, Yan Lue; Yin, Wai-Fong; Chan, Kok-Gan

    2015-06-20

    Pandoraea vervacti DSM 23571(T) is an oxalate metabolizing bacterium isolated from an uncultivated field soil in Mugla, Turkey. Here, we present the first complete genome sequence of P. vervacti DSM 23571(T). A complete pathway for degradation of oxalate was revealed from the genome analysis. These data are important to path new opportunities for genetic engineering in the field of biotechnology.

  9. Stimulation of Mn peroxidase activity: A possible role for oxalate in lignin biodegradation

    SciTech Connect

    Kuan, Iching; Tien, Ming )

    1993-02-15

    Oxalate is produced by numerous wood-degrading fungi. Our studies here show that the white-rot fungus Phaerochaete chrysosporium produces extracellular exalate under conditions that induce synthesis of the ligninolytic system. Little or no oxalate was detected in cultures grown under high nutrient nitrogen or carbon. This extracellular exalate was identified and quantitated by HPLC. Its identity was further substaintiated by its decomposition by the enzyme oxalate oxidase. The oxalate content of the extracellular fluid (peaking at 60 [mu]M) paralleled the extracellular activity of the lignin-degrading enzyme, Mn peroxidase. Significantly, we demonstrated that oxalate, at physiological concentrations, substantially stimulated Mn perosidase-catalyzed phenol red oxidation, presumably by its ability to chelate Mn. Stopped flow studies also indicate that oxalate accelerates the turnover of Mn peroxidase. Furthermore, we discovered that oxalate can support Mn peroxidase-catalyzed oxidations in the absence of exogenous H[sub 2]O[sub 2] and in the presence of dioxygen. These results allow us to propose an important role for oxalate, a ubiquitous compound produced by wood-destroying fungi, in lignin biodegradation. 27 refs., 5 figs.

  10. Determining the biochemical properties of the Oxalate Biosynthetic Component (Obc)1 from Burkholderia mallei

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxalic acid is produced by a variety of organisms ranging from simple microbes to complex animals. This acid has been proposed to fulfill various physiological and pathological functions which vary between organisms. In bacteria from the Burkholderia genus, oxalate secretion has been shown to be quo...

  11. The oxalic acid biosynthetic activity of Burkholderia mallei is encoded by a single locus

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although it is known that oxalic acid provides a selective advantage to the secreting microbe, our understanding of how this acid is biosynthesized remains incomplete. This study reports the identification, cloning, and partial characterization of the oxalic acid biosynthetic enzyme from the animal ...

  12. Effect of oxalic acid treatment on sediment arsenic concentrations and lability under reducing conditions.

    PubMed

    Sun, Jing; Bostick, Benjamin C; Mailloux, Brian J; Ross, James M; Chillrud, Steven N

    2016-07-05

    Oxalic acid enhances arsenic (As) mobilization by dissolving As host minerals and competing for sorption sites. Oxalic acid amendments thus could potentially improve the efficiency of widely used pump-and-treat (P&T) remediation. This study investigates the effectiveness of oxalic acid on As mobilization from contaminated sediments with different As input sources and redox conditions, and examines whether residual sediment As after oxalic acid treatment can still be reductively mobilized. Batch extraction, column, and microcosm experiments were performed in the laboratory using sediments from the Dover Municipal Landfill and the Vineland Chemical Company Superfund sites. Oxalic acid mobilized As from both Dover and Vineland sediments, although the efficiency rates were different. The residual As in both Dover and Vineland sediments after oxalic acid treatment was less vulnerable to microbial reduction than before the treatment. Oxalic acid could thus improve the efficiency of P&T. X-ray absorption spectroscopy analysis indicated that the Vineland sediment samples still contained reactive Fe(III) minerals after oxalic acid treatment, and thus released more As into solution under reducing conditions than the treated Dover samples. Therefore, the efficacy of enhanced P&T must consider sediment Fe mineralogy when evaluating its overall potential for remediating groundwater As.

  13. Total, Soluble and Insoluble Oxalate Contents of Ripe Green and Golden Kiwifruit

    PubMed Central

    Nguyễn, Hà Vũ Hồng; Savage, Geoffrey P.

    2013-01-01

    Three bulk samples of two different cultivars of kiwifruit, green (Actinidia deliciosa L.) and golden (Actinidia chinensis L.) were bought ripe, ready to eat from a local market. The aim of the study was to determine the oxalate composition of each of the three fractions of kiwifruit, namely skin, pulp and seeds. The pulp consisted of 90.4% of the edible portion of the two cultivars while the skin and seeds made up a mean of 8.0% and 1.6% respectively. Total oxalate was extracted with 2.0 M HCL at 21 °C for 15 min and soluble oxalates extracted at 21 °C in water for 15 min from each fraction. The total and soluble oxalate compositions of each fraction were determined using ion exchange HPLC chromatography. The pulp of golden kiwifruit contained lower amounts of total oxalates (15.7 vs. 19.3 mg/100 g FW) and higher amounts of soluble oxalates (8.5 vs. 7.6 mg/100 g FW) when compared to the green cultivar. The skin of the green cultivar contained lower levels of insoluble oxalates (36.9 vs. 43.6 mg/100 g FW), while the seeds of the green cultivar contained higher levels of insoluble oxalates 106.7 vs. 84.7 mg/100 g FW.

  14. Reflectance spectroscopy of oxalate minerals and relevance to Solar System carbon inventories

    NASA Astrophysics Data System (ADS)

    Applin, Daniel M.; Izawa, Matthew R. M.; Cloutis, Edward A.

    2016-11-01

    The diversity of oxalate formation mechanisms suggests that significant concentrations of oxalic acid and oxalate minerals could be widely distributed in the Solar System. We have carried out a systematic study of the reflectance spectra of oxalate minerals and oxalic acid, covering the 0.2-16 μm wavelength region. Our analyses show that oxalates exhibit unique spectral features that enable discrimination between oxalate phases and from other commonly occurring compounds, including carbonates, in all regions of the spectrum except for the visible. Using these spectral data, we consider the possible contribution of oxalate minerals to previously observed reflectance spectra of many objects throughout the Solar System, including satellites, comets, and asteroids. We find that polycarboxylic acid dimers and their salts may explain the reflectance spectra of many carbonaceous asteroids in the 3 μm spectral region. We suggest surface concentration of these compounds may be a type of space weathering from the photochemical and oxidative decomposition of the organic macromolecular material found in carbonaceous chondrites. The stability and ubiquity of these minerals on Earth, in extraterrestrial materials, and in association with biological processes make them useful for many applications in Earth and planetary sciences.

  15. Oxalic acid biosynthesis is encoded by an operon in Burkholderia glumae.

    PubMed

    Nakata, Paul A; He, Cixin

    2010-03-01

    Although the biosynthesis of oxalic acid is known to occur in a number of bacteria, the mechanism(s) regulating its production remains largely unknown. To date, there is no report on the identification of an oxalic acid biosynthetic pathway gene from bacteria. In an attempt to identify such a gene(s), a mutant screen was conducted using the simple oxalic acid-producing phytopathogenic bacterium, Burkholderia glumae. Four mutants that failed to produce oxalic acid were isolated from a transposon-mutagenized B. glumae library and named Burkholderia oxalate defective (Bod)1. DNA sequence analysis revealed that each mutant contained an insertion event at different sites in the same ORF, which we referred to as the oxalate biosynthetic component (obc)A locus. Complementation of the Bod1 mutant with the obcA gene, however, resulted only in a partial restoration of the oxalic acid-producing phenotype. Further complementation studies utilizing a larger DNA fragment encompassing the obcA locus coupled with deletion mutagenesis led to the identification of another ORF that we named the obcB locus, which was essential for higher levels of oxalic acid production. Transcript analysis indicated that both obcA and obcB are coexpressed and encoded on a single polycistron message.

  16. Desalted duck egg white peptides promote calcium uptake by counteracting the adverse effects of phytic acid.

    PubMed

    Hou, Tao; Liu, Weiwei; Shi, Wen; Ma, Zhili; He, Hui

    2017-03-15

    The structure of the desalted duck egg white peptides-calcium chelate was characterized by fluorescence spectroscopy, fourier transform infrared spectroscopy, and dynamic light scattering. Characterization results showed structural folding and aggregation of amino acids or oligopeptides during the chelation process. Desalted duck egg white peptides enhanced the calcium uptake in the presence of oxalate, phosphate and zinc ions in Caco-2 monolayers. Animal model indicated that desalted duck egg white peptides effectively enhanced the mineral absorption and counteracted the deleterious effects of phytic acid. These findings suggested that desalted duck egg white peptides might promote calcium uptake in three pathways: 1) desalted duck egg white peptides bind with calcium to form soluble chelate and avoid precipitate; 2) the chelate is absorbed as small peptides by enterocyte; and 3) desalted duck egg white peptides regulate the proliferation and differentiation of enterocytes through the interaction with transient receptor potential vanilloid 6 calcium channel.

  17. Equilibrium aluminium hydroxo-oxalate phases during initial clay formation; H +-Al 3+-oxalic acid-Na + system

    NASA Astrophysics Data System (ADS)

    Bilinski, Halka; Horvath, Laszlo; Ingri, Nils; Sjöberg, Staffan

    1986-09-01

    The conditions necessary for initial clay formation have been studied in different model systems comprising different organic acids besides Si and Al. In the present paper the solid phases and the precipitation boundary characterizing the subsystem H +-Al 3+-oxalic acid (H 2L) are discussed. pH and tyndallometric measurements were performed in an ionic medium of 0.6 M Na(Cl) at 25 °C. The two phases Al 3(OH) 7(C 2O 4) · 3H 2O (phase I) and NaAl(OH) 2(C 2O 4) · 3H 2O (phase II) determine the precipitation boundary. The following formation constants for the two phases were deduced: lgβ1 = lg([ Al3+] -3[ H2C2O4] -1[ H+] 9 = -21.87 ± 0.08 and lgβ11 = lg([ Al3+] -1[ H2C2O4] -1[ H+] 4 = -5.61 ± 0.06. Phase I exists in the range [ Al] tot≥ 10 -4.4moldm-3,[ H2C2O4] tot ≥ 10 -4.9moldm-3 and at pH < 6.8, thus being a possible precipitate in oxalic-rich natural waters. The more soluble sodium phase is unlikely to exist in natural waters. The two phases are metastable relative to crystalline gibbsite and may be considered as the first precipitation step in the transition from aqueous Al oxalates down to stable Al hydroxide. Model calculations illustrating these competing hydrolysis-complexation reactions are discussed in terms of predominance and speciation diagrams. The solid phases have been characterized by X-ray analysis of powders, TGA and IR spectra, and tentative structures are proposed. Phase I seems to be an octahedral layer structure, in which 3/5 of the octahedral sites between two close packed oxygen sheets are occupied by Al 3+ and the oxalate ion acts as a bridge ligand between two aluminium atoms. Phase II forms a more open sheet structure and has ion exchange properties. Powder data for a phase crystallized from the studied solution after a year are also presented. This phase, Na 4Al 2(OH) 2(C 2O 4) 4 · 10H 2O, supports the results from the equilibrium analysis of recent solution data by SJöBERG and ÖHMAN (1985), who have found the dinuclear

  18. Effect of oxalic acid on Nosema ceranae infection.

    PubMed

    Nanetti, Antonio; Rodriguez-García, Cristina; Meana, Aránzazu; Martín-Hernández, Raquel; Higes, Mariano

    2015-10-01

    Nosema ceranae is a honey bee pathogen parasitizing the ventricular epithelium and potentially causing colony death. The effect of 0.25 M oxalic acid solution administered to the bees in the form of sugar syrup was determined in laboratory and field trials. The spore numbers in an 8-day laboratory experiment were significantly lower when AO was administered (treated: 11.86 ± 0.94 s.e. × 10^6; untreated: 30.64 ± 0.31 s.e.x10^6). When administered in autumn to free flying colonies twice, 3 weeks apart, the infection prevalence decreased in young (relative reduction of 53.8% ± 6.5 s.e.) and old bees (relative reduction of 44.4% ± 6.0 s.e.). Meanwhile increased prevalence in all the controls was detected (young and old bees: relative increase of 45.7% ± 22.8 s.e. and 10.2% ± 5.9 s.e., respectively). While all the treated colonies overwintered correctly, the untreated ones did not (3 out of 5 were dead). In the absence of commercial products approved in several countries to control nosemosis, oxalic acid syrup appears promising in the development of alternative management strategies.

  19. Facile fabrication of cobalt oxalate nanostructures with superior specific capacitance and super-long cycling stability

    NASA Astrophysics Data System (ADS)

    Cheng, Guanhua; Si, Conghui; Zhang, Jie; Wang, Ying; Yang, Wanfeng; Dong, Chaoqun; Zhang, Zhonghua

    2016-04-01

    Transition metal oxalate materials have shown huge competitive advantages for applications in supercapacitors. Herein, nanostructured cobalt oxalate supported on cobalt foils has been facilely fabricated by anodization, and could directly serve as additive/binder-free electrodes for supercapacitors. The as-prepared cobalt oxalate electrodes present superior specific capacitance of 1269 F g-1 at the current density of 6 A g-1 in the galvanostatic charge/discharge test. Moreover, the retained capacitance is as high as 87.2% as the current density increases from 6 A g-1 to 30 A g-1. More importantly, the specific capacitance of cobalt oxalate retains 91.9% even after super-long cycling of 100,000 cycles. In addition, an asymmetric supercapacitor assembled with cobalt oxalate (positive electrode) and activated carbon (negative electrode) demonstrates excellent capacitive performance with high energy density and power density.

  20. Infrared, Polarized Raman, and SERS Spectra of Betaine Hydrogen Oxalate Monohydrate

    NASA Astrophysics Data System (ADS)

    Philip, Daizy; Aruldhas, G.

    1995-01-01

    Infrared and polarized Raman spectra of betaine hydrogen oxalate monohydrate are recorded and analyzed. The observed bands are assigned on the basis of vibrations due to oxalic acid, betaine, and water molecules. In the crystal it is found that oxalic acid molecules occupy a lower site and that betaine exists in zwitterionic form. Oxalic acid and water molecules are involved in strong hydrogen bending. Band assignments are confirmed by deuteration. Surface enhanced Raman scattering (SERS) spectra recorded in two silver colloids reveal chemisorption through different adsorption sites. The observed SERS spectra are interpreted on the basis of different adsorption sites, geometries, and adsorbate conformation/orientation. The change of the SERS spectrum with time is due to the different stabilities of the adsorbed states. The oxalic acid molecules of the compound are likely to be in a tilted orientation with respect to the silver surface.

  1. Calcium and Vitamin D

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Calcium is required for the bone formation phase of bone remodeling. Typically about 5 nmol (200 mg) of calcium is removed from the adult skeleton and replaced each day. To supply this amount, one would need to consume about 600 mg of calcium, since calcium is not very efficiently absorbed. Calcium ...

  2. A ratiometric fluorescent probe for oxalate based on alkyne-conjugated carboxamidoquinolines in aqueous solution and imaging in living cells.

    PubMed

    He, Chunsheng; Qian, Xuhong; Xu, Yufang; Yang, Chunmei; Yin, Liyan; Zhu, Weiping

    2011-02-07

    A novel ratiometric fluorescent probe for oxalic acid was designed and synthesized, based on the zinc-containing [DAQZ@2Zn(2+)] complex. It shows highly selective "on-off" fluorescence changes with a more than 20 nm blue shift in wavelength for oxalic acids in aqueous solution. Moreover, it can fluorescently respond to oxalic acid in living cells.

  3. An antagonist treatment in combination with tracer experiments revealed isocitrate pathway dominant to oxalate biosynthesis in Rumex obtusifolius L

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Oxalate accumulates in leaves of certain plants such as Rumex species (Polygonaceae). Oxalate plays important roles in defense to predator, detoxification of metallic ions, and in hydroxyl peroxide formation upon wounding/senescence. However, biosynthetic pathways of soluble oxalate are largely unkn...

  4. Molecular mechanisms of crystallization impacting calcium phosphate cements

    PubMed Central

    Giocondi, Jennifer L.; El-Dasher, Bassem S.; Nancollas, George H.; Orme, Christine A.

    2010-01-01

    The biomineral calcium hydrogen phosphate dihydrate (CaHPO4·2H2O), known as brushite, is a malleable material that both grows and dissolves faster than most other calcium minerals, including other calcium phosphate phases, calcium carbonates and calcium oxalates. Within the body, this ready formation and dissolution can play a role in certain diseases, such as kidney stone and plaque formation. However, these same properties, along with brushite’s excellent biocompatibility, can be used to great benefit in making resorbable biomedical cements. To optimize cements, additives are commonly used to control crystallization kinetics and phase transformation. This paper describes the use of in situ scanning probe microscopy to investigate the role of several solution parameters and additives in brushite atomic step motion. Surprisingly, this work demonstrates that the activation barrier for phosphate (rather than calcium) incorporation limits growth kinetics and that additives such as magnesium, citrate and bisphosphonates each influence step motion in distinctly different ways. Our findings provide details of how, and where, molecules inhibit or accelerate kinetics. These insights have the potential to aid in designing molecules to target specific steps and to guide synergistic combinations of additives. PMID:20308110

  5. Light-induced multiphase chemistry of gas phase ozone on aqueous pyruvic and oxalic acids: Aerosol chamber study

    NASA Astrophysics Data System (ADS)

    Gligorovski, S.; Grgic, I.; Net, S.; Böge, O.; Iinuma, Y.; Kahnt, A.; Scheinhardt, S.; Herrmann, H.; Wortham, H.

    2010-12-01

    The light-absorbing organic compounds present in and on condensed aerosol particles interacting with trace gases such as ozone can initiate a new and potentially important photo-induced multiphase chemistry. However, investigations of light induced multiphase processes are very scarce at present. We have launched the idea of pyruvic acid (PA) acting as a photosensitizer in the multiphase reactions between gas-phase ozone and aqueous oxalic acid (OA). The performed photochemical batch experiments yielded a complex suite of organic molecules which resulted primarily from the oligomerization of OA/PA and subsequent reactions, including decarboxylation and cycloadition (Grgic et al., 2010). In the atmosphere, pyruvic acid will always be accompanied by other carboxylic acids (and also other organics) which are constituents of either aerosol particles or aqueous droplets the effects of a possible photochemistry triggered by pyruvic acid should be experimentally studied in depth and under natural conditions as far as possible. Hence, in a very recent study experiments in the aerosol chamber facility LEAK at IFT, Leipzig, were performed to verify the influence of pyruvic on the multiphase (photo)oxidation of oxalic acid. The aim of these experiments was to study the multiphase photo-induced oxidation reactions with airborne deliquescent particles to demonstrate the applicability of the reactions mentioned above under more realistic conditions than in a batch reactor. State of the art sampling and analytical tools were applied for the analysis of the ongoing chamber runs and the formed particulate products which include denuder sampling, carbonyl compound derivatisation, PTR-MS measurements, GC-MS measurements and HPLC-MS and CE-MS for the particle phase. First results from these joint complex chamber experiments will be presented and discussed. Reference: Grgić I., Nieto-Gligorovski L.I., Net S., Temime-Roussel B., Gligorovski S., Wortham H. Light induced multiphase

  6. In vitro formation of Ca-oxalates and the mineral glushinskite by fungal interaction with carbonate substrates and seawater

    NASA Astrophysics Data System (ADS)

    Kolo, K.; Claeys, Ph.

    2005-04-01

    This study investigates the in vitro formation of Ca-oxalates and glushinskite through fungal interaction with carbonate substrates and seawater. In the first experiment, thin-sections prepared from dolomitic rock samples of Terwagne Formation (Carboniferous, Viséan, northern France) served as substrates. The thin sections placed in Petri dishes were exposed to fungi grown from naturally existing airborne spores. In the second experiment, fungal growth and mineral formation was monitored using only standard seawater (SSW) as substrate. Fungal growth media consisted of a high protein/carbohydrates and sugar diet with demineralised water for irrigation. Fungal growth process reached completion under uncontrolled laboratory conditions. The fungal interaction and attack on the carbonate substrates resulted in the formation of Ca-oxalates (weddellite CaC2O4·2(H2O), whewellite (CaC2O4·(H2O)) and glushinskite MgC2O4·2(H2O) associated with the destruction of the original substrate and its replacement by the new minerals. The seawater substrate resulted also in the formation of glushinskite and Ca-oxalates. Both of Ca and Mg were mobilized from the experimental substrates by fungi. The newly formed minerals and textural changes caused by fungal attack on the carbonate substrate were investigated using light and scanning electron microscopy (SEM-EDX), x-ray diffraction (XRD) and Raman spectroscopy. The results document the role of microorganisms in biomineralization, neo-mineral formation and sediment diagenesis. They also reveal the capacity of living fungi to interact with liquid substrates and precipitate new minerals. This work is the first report on the in vitro formation of the mineral glushinskite through fungal-carbonate and sea water substrates interactions processes.

  7. Investigation of mechanism of bone regeneration in a porous biodegradable calcium phosphate (CaP) scaffold by a combination of a multi-scale agent-based model and experimental optimization/validation

    NASA Astrophysics Data System (ADS)

    Zhang, Le; Qiao, Minna; Gao, Hongjie; Hu, Bin; Tan, Hua; Zhou, Xiaobo; Li, Chang Ming

    2016-08-01

    Herein, we have developed a novel approach to investigate the mechanism of bone regeneration in a porous biodegradable calcium phosphate (CaP) scaffold by a combination of a multi-scale agent-based model, experimental optimization of key parameters and experimental data validation of the predictive power of the model. The advantages of this study are that the impact of mechanical stimulation on bone regeneration in a porous biodegradable CaP scaffold is considered, experimental design is used to investigate the optimal combination of growth factors loaded on the porous biodegradable CaP scaffold to promote bone regeneration and the training, testing and analysis of the model are carried out by using experimental data, a data-mining algorithm and related sensitivity analysis. The results reveal that mechanical stimulation has a great impact on bone regeneration in a porous biodegradable CaP scaffold and the optimal combination of growth factors that are encapsulated in nanospheres and loaded into porous biodegradable CaP scaffolds layer-by-layer can effectively promote bone regeneration. Furthermore, the model is robust and able to predict the development of bone regeneration under specified conditions.

  8. Investigation of mechanism of bone regeneration in a porous biodegradable calcium phosphate (CaP) scaffold by a combination of a multi-scale agent-based model and experimental optimization/validation.

    PubMed

    Zhang, Le; Qiao, Minna; Gao, Hongjie; Hu, Bin; Tan, Hua; Zhou, Xiaobo; Li, Chang Ming

    2016-08-21

    Herein, we have developed a novel approach to investigate the mechanism of bone regeneration in a porous biodegradable calcium phosphate (CaP) scaffold by a combination of a multi-scale agent-based model, experimental optimization of key parameters and experimental data validation of the predictive power of the model. The advantages of this study are that the impact of mechanical stimulation on bone regeneration in a porous biodegradable CaP scaffold is considered, experimental design is used to investigate the optimal combination of growth factors loaded on the porous biodegradable CaP scaffold to promote bone regeneration and the training, testing and analysis of the model are carried out by using experimental data, a data-mining algorithm and related sensitivity analysis. The results reveal that mechanical stimulation has a great impact on bone regeneration in a porous biodegradable CaP scaffold and the optimal combination of growth factors that are encapsulated in nanospheres and loaded into porous biodegradable CaP scaffolds layer-by-layer can effectively promote bone regeneration. Furthermore, the model is robust and able to predict the development of bone regeneration under specified conditions.

  9. Calcium and Vitamin D

    MedlinePlus

    ... A calcium-rich diet (including dairy, nuts, leafy greens and fish) helps to build and protect your ... yogurt and cheese are high in calcium. Certain green vegetables and other foods contain calcium in smaller ...

  10. Coronary Calcium Scan

    MedlinePlus

    ... Scan Coronary Calcium Scan Related Topics Angina Atherosclerosis Coronary Heart Disease Electrocardiogram Heart Attack Send a link to NHLBI ... calcium, or calcifications, are a sign of atherosclerosis, coronary heart disease, or coronary microvascular disease. A coronary calcium scan ...

  11. Calcium uptake and release by isolated cortices and microsomes from the unfertilized egg of the sea urchin strongylocentrotus droebachiensis

    SciTech Connect

    Oberdorf, J.A.

    1986-01-01

    Two subcellular fractions of the sea urchin egg were studied for their potential role in regulating the transient rise in cytosolic calcium that accompanies fertilization. Isolated cortices from unfertilized sea urchin eggs sequester calcium in an ATP dependent manner when incubated in a medium containing free calcium levels characteristic of the resting cell. This ATP dependent calcium uptake activity, measured in the presence of 5mM Na Azide to prevent mitochondrial accumulation, was increased by oxalate, and was blocked by 150 ..mu..M quercetin and 50 ..mu..M vanadate. Cortices preloaded with /sup 45/Ca in the presence of ATP dramatically increased their rate of calcium efflux upon the addition of (1) the calcium ionophore A23187 (10 ..mu..M), (2) trifluoperazine (200 ..mu..M), (3) concentrations of free calcium that activated cortical granule exocytosis, and (4) the calcium mobilizing agent inositol trisphosphate (IP3). This pool of calcium is most likely sequestered in the portion of the egg's endoplasmic reticulum (ER) that remains associated with the cortical region during its isolation. They have developed a method for obtaining a high yield of purified microsomal vesicles from