Struvite (Total 1008 Papers Found)

The most important phosphates involved in urinary stone disease are carbonate apatite, brushite, and struvite. Overall, phosphate stones account for 12–20% of all stones, with a downward trend for struvite and an increase in carbonate apatite being observed in the last decade. The physicochemical basis for the formation of phosphate calculi is supersaturation. Once the solubility product has been exceeded, a metastable process of supersaturation begins, with slow crystalline growth. If a criti ...
Hydroxyurea is a well known enzyme urease inhibitor. Bacteria strains producers of enzyme urease can be the cause of struvite calculosis. Clinical studies have shown that treatment with hydroxyurea can produce acid urine in patients suffering from struvite calculosis. In this work antiurease and antibacterial activity of hydroxyurea was valued in vitro against Proteus mirabilis strains. Our results seem not to agree with the ones obtained in vivo. ...
Mineral solids precipitation is important in wastewater treatment. However approaches to minerals precipitation modelling are varied, often empirical, and mostly focused on single precipitate classes. A common approach, applicable to multi-species precipitates, is needed to integrate into existing wastewater treatment models. The present study systematically tested a semi-mechanistic modelling approach, using various experimental platforms with multiple minerals precipitation. Experiments includ ...
OBJECTIVES To examine the significance of the carbonation rate (CR) in carbonated apatite (carbapatite [CA]) stones and its relationships with the morphologic characteristics of CA and etiology. CA stones without struvite can result from metabolic disorders or urinary tract infection, but the latter etiology is still debated. Infection stones caused by urea-splitting bacteria are made of CA admixed with struvite and exhibit a high CO(3)(2-)/PO(4)(3-) ratio (CR). However, little is known as to th ...
INTRODUCTION We analyzed urinary calculi composition and its relationship with gender, age, calculus weight, color, and location. MATERIALS AND METHODS Two hundred and forty one patients with urinary calculus, who had undergone open lithotomy from June 1999 to April 2001, were enrolled in this prospective study which was performed by Tehran and Oroomieh Medical Sciences Universities. The calculi compositions were analyzed by infrared spectroscopy in Bonn University. Statistical analyses were m ...
OBJECTIVE To determine outcome of renal transplantation in cats with renal failure associated with calcium oxalate urolithiasis. DESIGN Retrospective case series. ANIMALS 19 cats. PROCEDURE Medical records were reviewed for evaluation of signalment, preoperative clinical signs, physical examination results, dietary history, clinicopathologic data, abdominal imaging, postoperative diet, complications, and long-term outcome. RESULTS The domestic shorthair was the most common breed represen ...
As phosphorus (P) resources are diminishing, the recovery of this essential nutrient from wastewaters becomes an increasingly interesting option. P-recovery through the controlled crystallization of struvite (MgNH4PO4·6H2O), a potential slow-release fertilizer, is highly attractive, but costly if large amounts of Mg have to be added. In this context, natural Mg-minerals like brucite (Mg(OH)2) could provide more cost-effective Mg-sources compared to high-grade Mg-compounds such as MgCl2. Here we ...
Uroliths obtained from 839 dogs were evaluated by quantitative methods. Struvite was the most prevalent mineral detected; newberyite, calcium oxalate, calcium phosphate, uric acid, sodium and ammonium urate, cystine, and silica were detected much less frequently. Seven per cent of the uroliths had an identifiable nucleus and one or more surrounding layers of different mineral types. Although uroliths were found in all parts of the urinary tract, the urinary bladder was most common. Uroliths of d ...
Crystallization of struvite and calcium phosphates was studied in vitro as encrustations on glass rods immersed in synthetic urine, to evaluate the crystallization capacity of Ureaplasma urealyticum and compare it with that of known urease and non-urease-producing bacteria. Inoculation of the synthetic urine with Ureaplasma urealyticum resulted in alkalinization of the synthetic urine and crystallization of struvite and brushite. Inoculation with Proteus mirabilis caused a faster and more pronou ...
In a series of 264 inpatients with nephrolithiasis and chronic renal insufficiency, 159 received follow-up care between 1 and 14 years (4.3 years on the average) after primary hospitalization. 59 of these 159 patients had to undergo nephrectomy in the course of calculus disease. Follow-up examinations showed no deterioration in 60 patients and a further 64 showed clear symptoms of improved renal function. In 23 patients renal function deteriorated and 11 of them had to be accepted in chronic dia ...
This paper presents a study of ammoniacal nitrogen removal by chemical precipitation resulting in the formation of ammonium and magnesium phosphat (MgNH4PO4∙6H2O), known as struvite, from the leachate in the Delta A landfill, located in the city of Campinas, São Paulo, Brazil. After the addition of a magnesium source (MgCl2∙6H2O), and phosphorus (Na2HPO4∙12H2O), ammoniacal nitrogen was precipitated as highly insoluble salt. The removal of ammoniacal nitrogen from the leachate exceeded 85% ...
Concurrent hydrogen (H2) production and phosphorus (P) recovery were investigated in dual chamber microbial electrolysis cells (MECs). The aim of the study was to explore and understand the influence of applied voltage and influent COD concentration on concurrent H2 production and P recovery in MEC. P was efficiently precipitated at the cathode chamber and the precipitated crystals were verified as struvite, using X-ray diffraction and scanning electron microscopy analysis. The maximum P precipi ...
A new chemolytic therapy with amino acid preparation was tried for use on struvite renal stones in two dogs, which were admitted to Azabu University Veterinary Teaching Hospital. No other special diet, for the purpose of dissolving the stones, was fed during the treatment. Dissolution of the stones began at week 1, and no stone was detected on radiography at week 4 in both cases. The amino acid preparation thereafter has been administered every 2-3 days to prevent formation of the stones. After ...
Recent studies have found that certain urinary proteins can efficiently inhibit stone formation. These discoveries are significant for developing effective therapies for stone disease, but the inhibition mechanism of crystallization remains elusive. In the present study, polyaspartic acid (PASP) was employed as a model peptide to investigate the effect of urinary proteins on the crystallization and morphological evolution of struvite. The results demonstrate that selective adsorption/binding of ...
Precipitation strategy of struvite-family crystals is presented in this paper to recover phosphate and potassium from a synthetic wastewater in the presence of citric acid at elevated temperature. The crystal-forming solutions were prepared from crystals of MgCl2 and NH4H2PO4 with a molar ratio of 1:1:1 for Mg+2, [Formula: see text], and [Formula: see text], and the citric acid (C6H8O7) was prepared (1.00 and 20.00 ppm) from citric acid crystals. The Rietveld analysis of X-ray powder diffracti ...
Re-thinking our approach to dealing with waste is one of the major challenges in achieving a more sustainable society. However, it could also generate numerous opportunities. Specifically, in the context of wastewater, nutrients, energy and water could be mined from it. Because of its exceptionally high nitrogen (N) and phosphorous (P) concentration, human urine is particularly suitable to be processed for fertiliser production. In the present study, forward osmosis (FO) was employed to mine the ...
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 distorti ...
Experiments were conducted to measure the behaviour of eight pharmaceuticals during urine treatment as part of the project 'SANIRESCH - Sustainable sanitary recycling Eschborn'. Urine was collected from 200 people in a public building via waterless urinals and NoMix toilets. It was then stored at room temperature at different pH values to analyse the extent to which bacteria and pharmaceuticals are eliminated over time. Although a partial elimination of pharmaceuticals could be detected, the sto ...
Understanding urolith trends and risk factors is important for understanding urolithiasis, which is a common problem in dogs. This study evaluated 75 674 canine cystolith submissions to the Canadian Veterinary Urolith Centre between 1998 and 2014. Struvite and calcium oxalate uroliths comprised 80.8% of all uroliths, with calcium oxalate outnumbering struvite. There were significant increases in the proportions of calcium oxalate, mixed and cystine uroliths, and significant decreases in struvite ...
The environmental benefits and burdens of phosphorus recovery in four centralized and two decentralized municipal wastewater systems were compared using life cycle assessment (LCA). In centralized systems, phosphorus recovered as struvite from the solids dewatering liquid resulted in an environmental benefit except for the terrestrial ecotoxicity and freshwater eutrophication impact categories, with power and chemical use offset by operational savings and avoided fertilizer production. Chemical- ...
A 66-year-old man was referred to the nephrologist because of recurrent episodes of afebrile low back pain, voiding-associated pain, and milky urine. Past history was positive for urolithiasis due to calcium oxalate stones, managed with hydrochlorothiazide 12.5 mg/day for the last 3 years. Chemistries revealed normal renal function and a urinalysis as described: density 1010; pH 7.5; proteinuria 0.6 g/l; leukocytes 20–30 per highpower field; pyocytes 10 per high-power field; abundant struvite ...
Cattle paunch is comprised of partially digested cattle feed, containing mainly grass and grain and is a major waste produced at cattle slaughterhouses contributing 20-30% of organic matter and 40-50% of P waste produced on-site. In this work, Temperature Phased Anaerobic Digestion (TPAD) and struvite crystallization processes were developed at pilot-scale to recover methane energy and nutrients from paunch solid waste. The TPAD plant achieved a maximum sustainable organic loading rate of 1-1.5k ...
Recent population studies have found symptomatic kidney stone formers to be at increased risk for chronic kidney disease (CKD). Although kidney stones are not commonly identified as the primary cause of ESRD, they still may be important contributing factors. Paradoxically, CKD can be protective against forming kidney stones because of the substantial reduction in urine calcium excretion. Among stone formers, those with rare hereditary diseases (cystinuria, primary hyperoxaluria, Dent disease, an ...
PURPOSE Percutaneous treatment of patients with calculi in a horseshoe kidney can be challenging due to the altered anatomical relationship in the retroperitoneum. Therefore, we performed a multi-institutional review to assess the safety and efficacy of this minimally invasive technique. MATERIALS AND METHODS Of 37 patients identified with calculi in a horseshoe kidney at 3 institutions 24 (65%) underwent percutaneous nephrolithotripsy as primary treatment. Average patient age was 48.4 years a ...
Struvite calculi occurring in patients with chronic urinary tract infections consist of an inorganic component of magnesium ammonium phosphate crystals and an underlying organic mucopolysaccharide matrix. Shock waves used to destroy these stones during extracorporeal shock wave lithotripsy (ESWL) therapy may affect the inorganic and organic components of the stone differently. In a 26-year-old woman, renal obstruction resulted from retained struvite stone matrix after ESWL therapy. ...
Struvite accumulation is a costly problem in many water resource recovery facilities (WRRFs) that use anaerobic digestion, causing significant labor and equipment costs and potentially impacting facility performance and permit compliance. A comprehensive study was undertaken to evaluate possible solutions to struvite control at two similar Miami-Dade County, Florida, WRRFs. Alternatives analyzed included periodic cleaning and repair of damaged piping and equipment; optimum ferric salt dosing, us ...
Analytical techniques have been used to determine constituents of urinary stones of different breeds of dogs obtained from the College of Veterinary Science and Animal Husbandry, Anand Agricultural University, India. Analysis by powder XRD, FTIR and TGA suggests the presence of pure phases such as calcium oxalate monohydrate, struvite and calcium carbonate, and also mixed phases containing calcium oxalate hydrate, struvite, whewellite and weddellite in the urinary calculi. The morphology of the ...
Chemical precipitation, in combination with a sequencing batch reactor (SBR) process, was employed to remove pollutants from anaerobic digester effluents of nylon wastewater. The effects of the chemicals along with various Mg:N:P ratios on the chemical precipitation (struvite precipitation) were investigated. When brucite and H(3)PO(4) were applied at an Mg:N:P molar ratio of 3:1:1, an ammonia-removal rate of 81% was achieved, which was slightly more than that (80%) obtained with MgSO(4)·7H(2)O ...
Urease is an important virulence factor for Helicobacter pylori and Proteus mirabilis as well as in environmental transformations of certain nitrogenous compounds. Urea hydrolysis caused by these microorganisms leads to increased pH and ammonia toxicity and enables bacterial colonization of the human gastric mucosa and urinary tract formation of struvite and carbonate-apatite stones. Due to the possibility of medical applications the development of novel, selective and efficient classes of ureas ...
Changes in stone composition according to time are commonly reported. Up to now, calcium oxalate nephrolithiasis was found constantly increasing in industrialized countries. In France, over the past two decades, we found that calcium oxalate tend to a plateau in males with a significant decrease of weddellite stones while the occurrence of uric acid calculi was increasing, in touch with the spread of obesity and type 2 diabetes. In parallel, an increase in brushite stones was observed in females ...
Microwave digestion of liquid dairy manure was tested for the release of nutrients, such as orthophosphates, ammonia-nitrogen, magnesium, calcium and potassium, both with and without the aid of an oxidizing agent (hydrogen peroxide). The orthophosphate to total phosphorus ratio of the manure increased from 21% to greater than 80% with 5 minutes of microwave treatment. More than 36% of total chemical oxygen demand (t-COD) of the manure was reduced when microwave digestion was assisted with peroxi ...
In this study, the effects of the combination of acid hydrolysis and Donnan dialysis on the high-quality struvite production from digested sewage sludge were examined. The Box-Behnken design was applied in the hydrolysis using oxalic acid for the optimization of the conditions that affect the nutrients and metal release from digested sludge. An optimal condition was obtained at oxalic acid 0.5 M, acid/sludge ratio (mL/g) 10/1, and reaction time 60 min. The separation of the metals from hydrolyze ...
A group of patients with struvite staghorn calculi were treated by combining percutaneous ultrasonic lithotripsy (PUL) and extracorporeal shock wave lithotripsy. Stone free rates at a mean follow-up of six months were only 23%. Far superior results have been achieved with PUL above. The primary treatment of struvite staghorn should be with PUL. Shock wave lithotripsy should be reserved for fragments difficult or dangerous to access. ...
The main objective of this study was to investigate the feasibility of coagulation as a post-treatment method of anaerobically treated primary municipal wastewater. Both mesophilic and ambient (20 degrees C) temperature conditions were investigated in a laboratory-scale upflow anaerobic sludge bed (UASB) reactor. In addition, optimization of the coagulant, both in terms of type and dose, was performed. Finally, phosphorus removal by means of aluminum and iron coagulation and phosphorus and ammon ...
The precipitation of magnesium phosphates in the system MgCl2-NH4H2PO4-NaOH-H2O was studied at a wide range of reactant concentrations at 37°C and an initial pHi of 7.4. Precipitates were aged for 24 h and characterized by means of optical and scanning electron microscopy, x-ray diffractometry, FT-IR spectroscopy and thermogravimetry. Struvite was found to precipitate in nearly the whole concentration region investigated. Pure newberyite and a mixture of struvite and newberyite were obtained i ...
The identification of calcium-binding proteins in urine and kidney stones has led to a closer look at the role of matrix proteins in urolithiasis. We analyzed five struvite stones for protein content and identified two bands (8 and 14 KDa) that were confirmed by gel electrophoresis and amino acid sequencing to be calgranulin. This protein, which is known by several other names, has bacteriostatic antifungal activity. Its role in the formation of struvite stones warrants further investigation. ...
Staghorn calculi are infrequent and generally are infected stones. Struvite or apatite calculi are embedded with gram-negative bacteria, which can produce endotoxin. Sepsis syndrome may occur after surgical therapy or endoscopic manipulation of infected or staghorn calculi. Sepsis, which can occur despite perioperative antibiotic use, may be due to bacteremia or endotoxemia. We present a child with an infected staghorn calculus who developed overwhelming sepsis and died after percutaneous stone ...
An overall treatment process for the removal of nitrogen, methane production and obtention of valuable fertilizers from dairy manure has been investigated in laboratory scale. Solid and liquid fractions were separated by flocculation and screening. The solid fraction contained 81.6%, 84.4%, 58.6% and 85.2% of TS, VS, TKN-N and P(T) originally present in manure. Batch anaerobic digestion of this solid fraction at 50°C resulted in methane production of 29.0 L CH(4)/kg. The liquid fraction, free o ...
Cement stabilization is used extensively to remediate soils contaminated with heavy metals. However, previous studies suggest that the elevated zinc (Zn) and lead (Pb) concentrations in the contaminated soils would substantially retard the cement hydration, leading to the deterioration of the performance of cement stabilized soils. This study presents a new binder, KMP, composed of oxalic acid-activated phosphate rock, monopotassium phosphate and reactive magnesia. The effectiveness of stabiliza ...
Brattleboro strain rats homozygous for hypothalamic diabetes insipidus (DI rat) excrete nearly their body weight per day in dilute urine and yet can form bladders stones composed of struvite and apatite. Studies were undertaken to investigate this apparent paradox. The results show that DI rat urine is indeed undersaturated with respect to struvite and apatite. However, chronic infection of DI rat urine with a urease-containing organism (Proteus mirabilis) results in the rapid formation of large ...
BACKGROUND AND PURPOSE Renal calculi may contain bacteria that can remain active inside the stone and produce bacteremia and/or endotoxemia after lithotripsy. Urinary tract infection associated with urinary stones represents high morbidity. The purpose of this research was to use novel artificial struvite stones inoculated with living bacteria and to study the effect of four different intracorporeal lithotripters on bacterial inactivation after in vitro lithotripsy. MATERIALS AND METHODS Two t ...
The technique and results of a recently developed surgical procedure for the relief of feline urethral obstruction are described. The method involves implanting a silicone shunt of comparable diameter into the pelvic urethra. Urine and struvite crystals are passed through the wide bore tube. The possibility of crystal accumulation and subsequent obstruction is thus avoided. ...
BACKGROUND AND PURPOSE Over the last 50 years, chemolysis as a primary or adjuvant treatment for urinary stones has fallen in and out of favor. We review the literature for a historical perspective on the origins and chronology of Renacidin therapy, focusing on landmark studies and impracticalities that have seemingly condemned it to history. MATERIALS AND METHODS A MEDLINE search was performed on the topic of chemolysis of urinary calculi. Historical literature was reviewed with regard to sto ...
Stone formation is an uncommon complication in renal allograft recipients. We report a 61-year-old woman who had undergone cadaveric renal transplantation in 1982 because of chronic renal failure due to polycystic kidney disease. Since 1985 she has developed recurrent urinary tract infections with Proteus mirabilis, and persistent microhematuria was detectable from 1988 on. Since renal function remained stable, she was repeatedly treated with antibiotics. Following a septicemia with P mirabilis, ...
Lowering supersaturation with respect to struvite and carbonate apatite is the most important prophylactic measure in patients with infection-induced kidney stone disease. This is best achieved by combining culture-specific antibiotics with urinary acidification. Urinary infection with non-urease-producing Escherichia coli, probably promoting struvite particle formation, must be eradicated. Possible measures for improving urothelial anti-adherence properties or reducing bacterial adherence are d ...
Sulphides are present in many wastewater streams; their removal is important due to corrosiveness, toxicity and unpleasant odour, and can be carried out by anaerobic biological treatment. This study focuses on the temperature effect (25-10 °C) on an expanded granular sludge bed (EGSB) reactor for sulphide removal using nitrate as electron acceptor. The reactor was run at a NO3-/HS- molar ratio of 0.35 and pH of 8.5-9.0. Samples were analysed by ion chromatography (NO3-, SO42- and S2O32-), spect ...
In some renal calculi whose structure was studied in thin sections, we have found large numbers of rods of the size and shape of bacteria, included in a material consisting of defective apatite calcium phosphates and organic matter. Electron transmission microscopy showed patterns of partially calcified bacteria. With the scanning electron microscopy we obtained only images of bacterial impressions. In struvite stones bacteria are rarely found in thin sections. Extremely high ammonium alkalinisa ...
Infektsteine sind mit ca. 15% an einem Gesamtharnsteinkollektiv (Industrieländer im Gegensatz zu Entwicklungsländern) beteiligt und stellen somit eine wichtige Gruppe dar. Sie bestehen meist aus Struvit und/oder Karbonatapatit. Grundvoraussetzung für die Bildung von Infektsteinen ist ein ureasepositiver Harnwegsinfekt (HWI). Urease setzt aus Harnstoff Ammoniak und CO2 frei. Die gebildeten Ammoniumionen und der infolge des Prozesses entstehende alkalische Urin sind Voraussetzungen für die Bi ...
The epidemiology of renal stones has changed all over the world toward a predominance of calcium oxalate stones. However, studies evaluating the influence of age and gender on the distribution of the various types of urinary calculi are scarce. We will present the results of a study based on 205 calculi (from 122 boys and 83 girls) analyzed by infrared spectroscopy between 1993 and 2007. 90% of stones were collected by surgery, whereas only 6% by spontaneous passage. The biological exploration w ...
We present a case of a giant bladder stone, 7.5 cm in diameter, found in the pelvis of a 19th-century natural mummy from Borgo Cerreto (central Italy). We used microchemical energy-dispersive x-ray spectroscopy analysis and x-ray diffraction to define the mineral composition of the stone and obtain information about its internal structure. Chemical analysis showed a mixed composition. The internal layers contained mostly ammonium acid urate, whereas the external layers were composed of magnesium ...