Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Struvite”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1994

Glycosaminoglycans and struvite calculi.

Glycosaminoglycans (GAGs) are suspended in urine and are present on tissue surfaces in the urinary tract. Consequently, they have the potential to influence any pathological disorder in this environment, including urinary tract infections by Proteus mirabilis and struvite (NH4MgPO4.6H2(0)) urolithiasis. Although GAGs, suspended in urine, may inhibit the formation of other types of calculus minerals, no such effect has been reported in struvite calculi. Nevertheless, GAGs are a major component of the organic matrix of all types of urinary calculi. In contrast, there is evidence that the GAG layer on the bladder surface may act as a defence mechanism against infection by inhibiting bacterial adhesion. More studies are needed to elucidate fully the role of GAGs in urinary infections and struvite urolithiasis.

Glycosaminoglycans↗
PubMed1987

Food intake and struvite crystalluria in ferrets.

Four adult, castrated, male ferrets were studied in two similar trials for effects of food intake on variables hypothesized to promote struvite (ammonium, magnesium, phosphate hexahydrate) crystal formation in urine. Struvite crystalluria occurred in three of the four ferrets. Urine pH (UpH) averaged 6.6 for these ferrets. UpH in the ferret without crystalluria was 6.0. By simple linear regression analysis, no relationship was found between the amount of food ingested and the urinary concentration and excretion of magnesium and phosphorous. However, urine osmolality and excretion of both protein and ammonium were correlated to food intake (P less than .05). Ways in which these effects could promote struvite crystal formation are discussed.

Animals↗
PubMed1989

Struvite crystal precipitation by different phenotypes of Yersinia.

Extracellular formation of struvite crystals by Yersinia enterocolitica, Y. frederiksenii, Y. kristensenii and Y intermedia strains was investigated. Precipitation of crystalline structures was found with 19 of the 187 strains tested, its formation being more frequently observed at 25 degrees C than at 37 degrees C. Production of struvite was greater in Y. enterocolitica strains belonging to biotype 1, serogroup 0:7,8 and lysotype Xz, than observed in other phenotypes. Quantitative assay in a liquid medium showed that struvite formation began after 3 d of incubation; production of these crystals increased up to 15 d. Crystalline structures were examined using electron microscopy and their extracellular formation was observed.

Crystallization↗
PubMed2001

Unusual facet cyst containing struvite and hydroxyapatite.

This case report describes a patient with severe back pain and radiculopathy. She was found to have a facet cyst within the lumbar spine that appeared to contain calcium on MRI and CT. Upon aspiration the cyst was found to contain calcium ammonium phosphate (struvite) and calcium phosphate (hydroxyapatite). Ammonia production in the presence of urease-producing bacteria is responsible for the production of struvite in the human body. We postulate that there was a prior infection of the facet with urease-producing bacteria, thus accounting for the production of the struvite within the facet cyst.

Durapatite↗
PubMed2026

Organic Molecules are Involved in Ni-Struvite Biomineralization by Streptomyces mirabilis.

The Gram-positive, filamentous soil bacterium Streptomyces mirabilis P16B-1 has been shown to tolerate high environmental concentrations of Ni. The extremely high metal tolerance is partly provided through biomineralization, observed for both Mg bearing struvite and Ni-struvite where Ni ions replace Mg in the mineral lattice. The minerals showed different morphologies. This led us to assume that excreted substances may have the capacity to influence the mineral formation process that occurs at a distance to the cells. Here, we could show with metabolomics and proteomics studies that 23 metabolites as well as 18 proteins potentially co-precipitate with the minerals. Secreted secondary metabolites reduced in the supernatant after mineralization were identified as ergothioneine, diacetyllegionaminic acid, nevaltophin F, and diaminonaphthalene. The compounds phenylacetaldehyde and margaric acid also reduced after mineral precipitation did not alter mineral macromorphology. In addition, ten proteins that co-precipitated with statistical significance were predicted to be secreted. Among those, a specific nickel binding protein, NikA, was reduced in high amounts from the supernatant upon crystal formation. The potential of secreted organic molecules and proteins to bind specific surfaces of the mineral thereby redirecting crystal growth in a microbially influenced biomineralization process. Implications for biotechnological metal-struvite use are discussed.

Nickel↗
PubMed2006

Removal of ammonia as struvite from anaerobic digester effluents and recycling of magnesium and phosphate.

A second order kinetic model was developed to predict the rate and extent of NH(4)(+) removal as struvite from anaerobic digester effluents. Alternative to this, NH(4)(+) can be recovered from struvite and the remaining Mg(2+) and PO(4)(3-) can be recycled back to the wastewater to fix more NH(4)(+). The NH(4)(+) solution was retained and the remaining Mg(2+) and PO(4)(3-) were returned back to be mixed with wastewater. In a five-step process, NH(4)(+) recovery was initially 92% and progressively decreased to 77% in the fifth stage, due to loss of Mg(2+) and PO(4)(3-) at each step in the supernatant. Finally, economic analysis of recycling nutrients was performed and compared to the one step process. The cost of NH(4)(+) recovery was calculated as $0.36/kgNH(4)-N which is lower than $7.7/kgNH(4)-N the cost of one step process without considering the market value of struvite obtained in one step process.

Anaerobiosis↗
PubMed2005

Raman spectroscopy of newberyite, hannayite and struvite.

The phosphate minerals hannayite, newberyite and struvite have been studied by Raman spectroscopy using a thermal stage. Hannayite and newberyite are characterised by an intense band at around 980cm(-1) assigned to the v(1) symmetric stretching vibration of the HPO(4) units. In contrast the symmetric stretching mode is observed at 942cm(-1) for struvite. The Raman spectra are characterised by multiple v(3) anti-symmetric stretching bands and v(2) and v(4) bending modes indicating strong distortion of the HPO(4) and PO(4) units. Hannayite and newberyite are defined by bands at 3382 and 3350cm(-1) attributed to HOPO(3) vibrations and hannayite and struvite by bands at 2990, 2973 and 2874 assigned to NH(4)(+) bands. Raman spectroscopy has proven most useful for the analysis of these 'cave' minerals where complex paragenetic relationships exist between the minerals.

Magnesium Compounds↗
PubMed2001

Gastric patch pyeloplasty: development of an animal model to produce upper tract urinary acidification for treating struvite urinary calculi.

PURPOSE: Struvite calculi form in an alkaline environment created by urease producing uropathogens. We developed a viable upper tract urinary acidification model by performing gastric patch pyeloplasty in the rabbit. This model produces urinary acidification sufficient for the treatment and prevention of struvite renal calculi. We evaluated the physiological, metabolic and surgical outcomes. MATERIALS AND METHODS: gastric segment was harvested based on branches of the left gastro-epiploic artery. The flap was folded along the transverse axis and the adjacent edges were closed. The mouth of this reconfigured pouch provided optimal dimensions for anastomosis with the diminutive renal pelvis. Half of the rabbits were treated with internal stenting and H-2 blockade. Urinary pH was assessed by weekly cage collection and direct collection from the cannulated ureters. Urine culture was done, and serum gastrin and electrolytes were assessed at regular intervals. The rabbits were sacrificed at 3 to 26 weeks. Histological examination was routinely performed. RESULTS: A total of 15 rabbits were available for complete assessment. Sustained urinary acidification was produced in 7 animals (47%) with a mean pH decrease of 2.27. In another 2 rabbits (13%) the urine was initially acidic but subsequently became alkaline due to ureteral obstruction. Electrolytes and gastrin were unchanged in these rabbits and urine culture was positive in 2. Histological testing revealed nonspecific inflammatory changes of the renal pelvis. Anastomotic complications were the most common surgical complication and the most common cause of failed acidification. The cohort treated without stents and H-2 blockade was at significantly greater risk for anastomotic leakage. CONCLUSIONS: Gastric patch pyeloplasty may significantly increase urinary acidity in the rabbit model without altering the serum electrolyte balance or gastrin level. The procedure utilizes common techniques of reconstructive urology and may be possible with laparoscopy. Further study is required to assess the in vivo effect of this procedure for treating and preventing upper tract struvite calculi.

Animals↗
PubMed1992

Struvite stone formation by Corynebacterium group F1: a case report.

Struvite stones are caused by urea-splitting, usually gram-negative, organisms. A case of aggressive struvite stone production caused by Corynebacterium group F1 is reported that responded to the appropriate antibiotic treatment. To our knowledge this organism has never been associated previously with struvite stone formation.

Adult↗
PubMed2002

Struvite formation, control and recovery.

Recent legislation on the removal of nutrients from wastewater has led to a number of operation problems with struvite scaling. Struvite is MgNH4PO4 x 6H2O and this paper reviews the formation, control and recovery of struvite from primarily municipal wastewater and other waste streams. Treatment options for control and technologies for recovery are discussed.

Chemical Precipitation↗
PubMed2002

Struvite formation and the fouling propensity of different materials.

Struvite (MgNH4PO4 x 6H2O) fouling was investigated to identify the impact supersaturation and material had on scaling rates. Tests were undertaken at three supersaturation ratios and with three different materials: stainless steel, teflon and acrylic. Impellers consisting of a clasp unit and two corrosion coupons that could be attached were used to mix centrate liquor and precipitation was initiated by the change in pH caused by degassing. Increasing the supersaturation ratio from 1.7 to 5.3 led to a doubling in the scaling rate of stainless-steel coupons. Experiments with acrylic and teflon coupons showed the influence of surface roughness upon scaling propensity. Coarsely roughened coupons following 40 h of mixing had a mass of 413 mg of struvite attached compared to smooth coupons that had a mass of 240 mg attached. Material did have an influence upon struvite fouling but this influence diminished with increasing surface roughness.

Hydrogen-Ion Concentration↗
PubMed2000

Effect of culture conditions on the formation of struvite by Myxococcus xanthus.

The amount of struvite (MgNH4PO4 x 6H2O) produced by Myxococcus xanthus as well as the culture parameter values (pH, total phosphorus, total Kjeldahl nitrogen) were dependent on the culture medium used. Struvite formation started during the exponential phase and the maximum concentration was observed at the beginning of stationary growth phase. The addition of each medium component to the liquid culture influenced the amount of crystal produced. This amount did not depend on the pH increase during the culture period. The moment of the bacterial growth phase, at which each medium component was added, influenced the struvite formation.

Bacteriological Techniques↗
PubMed2004

Use of a byproduct of magnesium oxide production to precipitate phosphorus and nitrogen as struvite from wastewater treatment liquors.

This paper describes a series of experiments designed to recover phosphorus and nitrogen from sewage in the form of struvite (MgNH(4)PO(4).6H(2)O), a potential fertilizer. Nitrogen and phosphate were recovered from a filtrate of digested sludge dewatered at the Arroyo del Soto Waste Water Treatment Plant (WWTP) (Madrid, Spain). A byproduct of the Spanish magnesite mining and MgO production industry was used as the magnesium source. The precipitating performance of this byproduct was compared to that of conventional chemical reagents such as pure MgO. The precipitates obtained were subjected to chemical, light microscopy, and X-ray diffraction analysis. The findings indicate the precipitate recovered using this byproduct contains several minerals with a predominance of struvite. Optimal purity ( approximately 80% struvite) was achieved using the sieved <0.04 mm grain size fraction of the byproduct at doses corresponding to a molar Mg:P ratio of 1.6.

Chemical Precipitation↗
PubMed1984

A randomized double-blind study of acetohydroxamic acid in struvite nephrolithiasis.

We studied the effects of the bacterial urease inhibitor acetohydroxamic acid on the growth of struvite stones in the urinary tract. Eighteen patients who received acetohydroxamic acid (15 mg per kilogram of body weight per day, in divided oral doses) for a mean of 15.8 months were compared in a randomized double-blind study with 19 patients who received placebo for a mean of 19.6 months. Seven patients given placebo reached a pre-determined end point: a 100 per cent increase in the two-dimensional surface area of their stones. No patient who received acetohydroxamic acid had a doubling of stone size (P less than 0.01). Nine patients receiving the drug and one patient receiving placebo required a decrease in dosage or cessation of treatment because of adverse effects (P less than 0.01). Episodes of tremulousness (n = 5, P less than 0.05), which reversed with a decrease in drug dose, and phlebothrombosis (n = 3, P not significant) were limited to the group given acetohydroxamic acid. We conclude that acetohydroxamic acid effectively inhibits the growth of struvite stones in the short term in patients infected with urea-splitting bacteria, but the prevalence of adverse reactions appears to be high and the toxicity and effectiveness of long-term therapy for struvite nephrolithiasis remain to be defined.

Adult↗
PubMed2004

Laboratory studies on recovery of N and P from human urine through struvite crystallisation and zeolite adsorption.

Struvite [Mg (K, NH4)(PO4) x 6H2O] crystallisation and adsorption to zeolite have been proposed as a method for nutrient recovery from human urine collected with urine separating toilets. The aim of the present study was to optimise the use of MgO (to precipitate struvite) and zeolite (to adsorb ammonia) in this process. The experiments were performed with fresh urine, to which various amounts of MgO and zeolite were added. After repeated stirring and settling for 3 days the supernatant was analysed for pH, total-N, total-P and acute toxicity for Daphnia magna (24- and 48-h EC50). The results show that addition of MgO reduced P and addition of zeolite reduced N in the supernatant, as expected. The required concentration of MgO added was less than expected from the stoichiometric Mg-P-ratio for struvite. In combination with zeolite the requirement for MgO was reduced even further. Zeolite was effective in reducing total-N, but because of its interaction with MgO the effect of zeolite on N as well as P reduction was rather complicated. The optimal combination of MgO and zeolite for combined N and P recovery was found to be around 0.5 MgO per litre urine and 15 g zeolite per litre urine. These additions reduced supernatant P from about 1300 mg l(-1) to 10 mg l(-1) and N from 8000 mg l(-1) to 1000 mg l(-1). The 24-h EC50 for D. magna was not significantly affected by these additions. The expected recovery potentials for P and N by addition of MgO and zeolite are, thus, about 99% for P and 90% for N. However, these figures need to be verified, and pilot plant experiments at a science centre with urine separation wastewater treatment (www.universeum.se) are in progress.

Adsorption↗
PubMed2001

Three years experience of operating and selling recovered struvite from full-scale plant.

The adoption of phosphorus removal at sewage treatment works (STW) creates two main problems. Firstly large amounts of sludge are produced and secondly the quantity of the effluent deteriorates due to the increase in the phosphorus load of the sidestream. Furthermore, these processes do not remove phosphorus in a form that would enable it to be recycled. Therefore in order to control these process difficulties and produce a recyclable phosphorus product a sidestream struvite crystallisation reactor was developed. The struvite was produced in a fluidised bed reactor using dewatered filtrate from anaerobic sludge digestion. Magnesium hydroxide was added in a magnesium to phosphate ratio of 1:1 and the pH was adjusted to between 8.2-8.8 with the addition of sodium hydroxide. A retention time of 10 days alowed the growth of pellets between 0.5-1.0 mm in size. The recovered struvite contained only minute traces of toxic substances and was sold to fertiliser companies for 27,000 yen tonne(-1). It is used to enhance existing fertilisers, which are widely used on paddy rice, vegetables and flowers.

Agriculture↗
PubMed1999

Struvite stones.

Struvite stones constitute only about 2-3% of the stones reaching the laboratory for analysis, but the clinical problems they create including sepsis and even renal demise are greater than with any other stone type. This article reviews the evidence that bacterial urease, usually from a Proteus species, is responsible for the chemical changes in urine which result in struvite formation. Available urease inhibitors and other forms of medical management of patients with these stones are discussed. A patient with struvite stones should be assumed to have a progressive disease which cannot be ignored. Even after seemingly successful elimination of stones with lithotripsy and/or percutaneous nephrolithotomy, careful medical follow-up is critical. The medical profession is probably underutilizing postprocedure hemiacidrin irrigation because of shortsighted financial considerations. Primary-care physicians need to be educated in the importance of aggressive management of Proteus and other urea-splitting infections.

Adult↗
PubMed2006

Application of a fuzzy algorithm for pH control in a struvite crystallisation reactor.

A struvite crystallisation process is highly dependent on pH. To achieve a high phosphorus recovery as struvite it is important to have an accurate control of pH in the reactor. The high non-linear response of pH value makes manual pH control difficult. Therefore, a software based on fuzzy logic control (FLC) has been developed to maintain the pH at a set value in a stirred reactor to crystallise struvite. The FLC developed has been based on Larsen's inference. In order to confirm the improvement of the pH stability using FLC software, different experiments have been carried out with manual control of the pH value, and with the FLC software. It has been demonstrated that using FLC software allows a precise control of pH with high stability, optimises the process, and minimises the operator intervention.

Algorithms↗