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PubMedDate not supplied

New drug therapy for kidney stones: a review of cellulose sodium phosphate, acetohydroxamic acid, and potassium citrate.

Kidney stones have an overall incidence of two to three percent in western countries. In many patients, the disease process is difficult to control and recurrence rates are high: 20 to 50 percent over the subsequent ten years. The pathogenesis and standard methods of treatment for the five major types of stones (i.e., calcium oxalate, struvite, calcium phosphate, uric acid, and cystine) are reviewed. Three new drugs are reviewed in the context of their roles in the selective treatment of kidney stones. Cellulose sodium phosphate (Calcibind) is a nonabsorbable ion-exchange resin with a limited indication for the treatment of calcium stones associated with absorptive hypercalciuria Type I. Acetohydroxamic acid (Lithostat) is an urease-inhibitor that is indicated as adjunctive therapy in patients with chronic urea-splitting urinary tract infections and struvite stones. Potassium citrate (Urocit) is an investigational agent that has clinical efficacy in patients with calcium oxalate and calcium phosphate stones who are hypocitraturic. In addition, potassium citrate is an alkalinizing agent that can be used in patients with uric acid stones.

Adult↗
PubMedDate not supplied

The efficacy of non-contrast helical computed tomography in the prediction of urinary stone composition in vivo.

The composition of urinary stones was predicted on the basis of the differences in their Hounsfield unit (HU) densities as detected by in vivo non-contrast helical computed tomography (NCHCT). A total of 87 stones, which had been obtained from patients admitted to the emergency department with acute flank pain, were analysed biochemically. These stones had been visualized by NCHCT before spontaneous passage, ureteroscopic extraction or surgical removal, and their HU densities had been recorded. The HU densities of the stones were compared with the results of biochemical analysis. The mean HU densities of the stones composed of calcium oxalate (n = 54), struvite (n = 19) and uric acid (n = 14) were 812 +/- 135, 614 +/- 121 and 413 +/- 143, respectively. The differences between the mean HU densities of these three stone types were statistically significant. This initial clinical study demonstrated that in vivo NCHCT analysis may be used to predict the composition of urinary stones.

Calcium Oxalate↗
PubMed2006

Renal lithiasis and nutrition.

Renal lithiasis is a multifactorial disease. An important number of etiologic factors can be adequately modified through diet, since it must be considered that the urine composition is directly related to diet. In fact, the change of inappropriate habitual diet patterns should be the main measure to prevent kidney stones. In this paper, the relation between different dietary factors (liquid intake, pH, calcium, phosphate, oxalate, citrate, phytate, urate and vitamins) and each type of renal stone (calcium oxalate monohydrate papillary, calcium oxalate monohydrate unattached, calcium oxalate dihydrate, calcium oxalate dihydrate/hydroxyapatite, hydroxyapatite, struvite infectious, brushite, uric acid, calcium oxalate/uric acid and cystine) is discussed.

Calcium Oxalate↗
PubMed1997

A modified semi-automated technique for in vitro assessment of encrustation of materials.

In vitro study of encrustation is an important part of assessment of materials as potential alloplasts or devices in the urinary tract. This modified semi-automated technique comprises a circular reaction chamber with an encrustation mixture, the level of which is controlled by a float switch which operates the exit peristaltic pump. The composition of the reactants used simulates infected urine with alkaline pH. Results of a preliminary study of the deposits by scanning electron micrography (SEM) and energy dispersive X-ray (EDX) microanalysis are consistent with struvite and hydroxyapatite, similar to the main minerals deposited on urinary catheters. It is a relatively simple, effective and inexpensive set-up for study of encrustation on materials.

Biocompatible Materials↗
PubMed2002

The influence of ligand side chain on the enantioselectivity of Lewis acid catalyzed Diels-Alder reactions.

The enantioselective Lewis acid-catalyzed Diels-Alder reaction of 3-(2-propenoyl)-1,3-oxazolidin-2-one 8 with cyclopentadiene was examined using a series of chiral mox ligands 2-6, deferring in the side chain at 2-position of the chiral oxazoline and in the nature of the substituent at the chiral center (4-position) of the oxazoline ring, and a combination of N-[(1R)-2-chloro-1-phenylethyl]-2-[(4R)-4-phenyl-4,5-dihydrooxazol-2-yl]butyramide 2-MgI(2)-I(2) was the most efficient catalyst.

Catalysis↗
PubMed2003

The first example of alpha-thiomagnesiums generated from dithioacetal monoxides with Grignard reagent; their properties and some synthetic applications.

Dithioacetal monoxides were synthesized from aldehydes and cyclohexanone, and reaction of the dithioacetal monoxides with Grignard reagents was investigated. The dithioacetal monoxide synthesized from alkylaldehyde and 4-chlorobenzenethiol reacted with i-PrMgCl to afford the desired alpha-thiomagnesium in high yield. The generated alpha-thiomagnesium was found to be stable at room temperature and to be useful in organic synthesis. In contrast to this, the dithioacetal monoxides derived from benzaldehyde and cyclohexanone did not give satisfactory results.

Acetals↗
PubMed2006

Evaluation of binders in the preparation of medicinal carbon tablets by wet granule compression.

Medicinal carbon (MC) tablets were prepared to obtain an oral dosage form that can be easily taken. The MC tablets were made by the wet granule compression method, in which hydroxypropyl cellulose (HPC), carboxymethyl cellulose sodium (CMC-Na) and maltitol (MT) were applied as binders. Brilliant Blue FCF (BB) was used as a model drug. The binders were evaluated in terms of formability of the granules and tablets, their strength, disintegration of the tablets, and their effect on the adsorption potential of MC. HPC and CMC-Na gave the strong granules at a fairly low concentration, but more MT was needed to obtain the strong granules. The tablets could be formed only when using MT at 120% (w/w) of the MC amount. The tablet displayed good hardness and rapid disintegration. The adsorption potential was not affected by CMC-Na, and slightly prevented by MT. However, the adsorption ability of MC was lowered more with the increase in HPC. The granules and tablets exhibited similar adsorption potentials, which were a little lower than that of MC suspended in MT aqueous solution. Similar adsorption characteristics were also observed in a real drug, acetaminophen. It is suggested that the MC tablets prepared by the wet granule compression using MT as a binder should be useful as a compact dosage form of MC.

Adjuvants, Pharmaceutic↗
PubMed1992

Struvite urolithiasis in a B6C3F1 mouse.

In a 2 year carcinogenicity bioassay using B6C3F1 mice, one male mouse developed clinical signs near termination of the study, comprising skin sores around the prepuce, penile prolapse and urine scalding. The predominant finding at necropsy was a markedly distended urinary bladder filled with numerous crystallized particles. Microscopically, there was subacute cystitis with marked hyperplasia of the transitional epithelium. X-ray diffraction analysis of the crystals showed a diffraction pattern characteristic of struvite (ammonium magnesium phosphate). The implications of the spontaneous occurrence of bladder stones in rodents on long-term toxicology studies are discussed.

Animals↗
PubMed1998

The absorption of iron, calcium, phosphorus, magnesium, copper and zinc in the jejunum-ileum of control and iron-deficient rats.

The effects of iron deficiency on the absorption of different dietary sources of iron were studied, together with the interactions between iron, calcium, phosphorus, magnesium, copper and zinc in the jejunum-ileum of control and iron-deficient rats. In this study, three perfusion solutions containing different iron sources: ferric citrate, haemoglobin, and equal parts of ferric citrate and haemoglobin were used. In addition, the same perfusion solutions were used with and without 2,4-dinitrophenol, an inhibitor of oxidative phosphorylation. Iron absorption in anaemic rats was greater than in the controls, except after perfusion with solutions containing haemoglobin. The absorption of calcium, copper and zinc in iron-deficient animals was not significantly affected, while the absorption of phosphorus and magnesium increased, with respect to animals in the control group. After perfusion with solutions containing haemoglobin, the absorption values of calcium, copper and zinc were lower than after ferric citrate in both groups (control and iron-deficient rats).

2,4-Dinitrophenol↗
PubMed2005

The low energy X-ray response of the LiF:Mg:Cu:P thermoluminescent dosemeter: a comparison with LiF:Mg:Ti.

LiF:Mg:Cu:P thermoluminescent dosemeters (TLD) can be used for the same X-ray dosimetry applications as LiF:Mg:Ti, with each type having the disadvantage of a response dependent on energy, particularly at low energies. Measurements were made of the response per unit air kerma of LiF:Mg:Cu:P and LiF:Mg:Ti to nine quasi-monoenergetic X-ray beams with mean energies from 12 keV to 208 keV. Each measurement was normalized to the value produced by 6 MV X-rays. LiF:Mg:Cu:P was found to under-respond to a majority of these radiations whereas LiF:Mg:Ti over-responded to a majority. Their smallest relative measured response was produced by the lowest energy beam, and the maximum measured relative response of 1.15+/-0.07 and 1.21+/-0.07 for LiF:Mg:Cu:P and LiF:Mg:Ti, respectively, occurred at 33 keV. Energy response coefficients were derived from these measurements to estimate the error introduced by using either type of TLD to measure the dose from an X-ray spectrum different to that used for its absolute response calibration. It was calculated that if the response of either type of TLD was calibrated at 100 kVp, then an error of no more than +/-2% would be introduced into measurements of tube output at potentials of 50-130 kVp. LiF:Mg:Cu:P was found to introduce a larger error (up to 30%) into the measurement of body exit dose than LiF:Mg:Ti at tube potentials of 40-150 kVp, if its absolute response was calibrated using the corresponding body entrance beam. The method should allow this type of error to be estimated in other dosimetry applications for either type of TLD.

Copper↗
PubMed2000

Medical dissolution of struvite nephrolithiasis using amino acid preparation in dogs.

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 6 months from treatment, complete dissolution was confirmed, and no relapse has been observed. Therefore, it is concluded that chemolytic therapy with amino acid preparation might be useful for the treatment of nephrolithiasis with struvite renal stones in dogs.

Animals↗
PubMed2001

Effect of supplementation of dry cat food with D,L-methionine and ammonium chloride on struvite activity product and sediment in urine.

Feeding dry foods supplemented with urine acidifier (D,L-methionine (Met) or ammonium chloride) decreased urinary pH and struvite activity product in clinically normal cats. As a result, the number of struvite crystals in urine was greatly reduced. Supplementation with 3% Met but not 1% Met caused decrease in the urinary concentration of sediment, which resulted from a reduction in the HCl-soluble fraction. The concentration of HCl-insoluble sediment was not affected by supplementation with the urine acidifier.

Ammonium Chloride↗
PubMed2004

Surface plasmon spectral fingerprinting of adsorbed magnesium phthalocyanine by angle and wavelength modulation.

A novel instrumental method for angle and wavelength modulated surface plasmon resonance (SPR) spectroscopy is applied to the problem of spectral selectivity in SPR experiments. For transparent analytes, SPR reflectivity data are reduced to a two-dimensional (2D) spectrum of resonance wavelength versus incident angle, lambdaSPR(theta). This spectrum encodes the refractive index (RI) dispersion of the analyte and illustrates the increased SPR spectral shift per unit RI change at longer wavelengths (lower angle). For the absorbing analyte magnesium phthalocyanine (MgPc), the 2D data reduction method is complicated by the way the SPR and MgPc-based spectral peaks mix. Fresnel reflectivity models support experimental observations of spectral branching and qualitative fingerprints in the form of branched spectra, and difference reflectivity deltaR(lambda, theta) contour plots are presented.

Adsorption↗
PubMed2006

Experimental and computer modelling speciation studies of the effect of pH and phosphate on the precipitation of calcium and magnesium salts in urine.

BACKGROUND: pH and phosphate concentration are the major determinants of precipitation in urine of the salts of calcium and magnesium. This study aims to model the process of salt precipitation and establish whether the acidification of urine samples is necessary for the accurate measurement of calcium and magnesium in a clinical laboratory setting. METHODS: Urine samples were collected from 21 patients, aliquots were taken from each patient sample and the pH was adjusted to cover the range 2.0-10.0. The analytical and biological variation for each analyte was established and used to calculate percentage changes and critical differences. The critical difference was used to assess whether there was a significant difference between acidified and un-acidified samples. The JESS (Joint Expert Speciation System) thermodynamic computer-modelling program was used to predict the distribution of salt species formed with varying pH values and phosphate levels in simulated urine. RESULTS: The results showed that at a pH greater than 6.5, measured calcium, magnesium and phosphate significantly decreased as a result of precipitation (p<0.0001), although the critical difference was generally not exceeded. Computer modelling showed that both pH and phosphate concentration affected the distribution of salt species formed, as well as the precipitation patterns of calcium and magnesium phosphates. Overall, calcium phosphate precipitation tends to predominate at lower phosphate concentrations and at pH values below about 6.5, while both calcium and magnesium phosphate precipitation occur at higher phosphate concentrations and pH values greater than 6.5. CONCLUSIONS: For accurate analysis of these analytes in urine, the pH should be routinely measured and acidification should be undertaken prior to analysis if the pH is greater than 6.5. Based on the findings of this study, acidification or the lack of it does not result in a clinically significant change in calcium, magnesium and phosphate measured in urine. This study also predicted the likely salt species formed at varying urinary pH values and phosphate concentrations.

Calcium↗
PubMed2000

Encrusted pyelitis of native kidneys.

This study reports the first four cases of encrusted pyelitis involving native kidneys. The clinical features, management, and outcome of these patients were analyzed. Predisposing factors were underlying urologic disease and/or urologic manipulations, debilitating diseases, hospitalization, and prolonged antibiotic therapies. Presenting symptoms were renal failure in three patients with ureteroileal urinary diversion and manifestations of cystitis in one patient. Computed tomography scan of the urinary tract was critical for diagnosis. Presence of struvite was demonstrated by crystalluria and infrared spectrophotometry analysis of the encrusted material. Corynebacterium urealyticum urinary infection was identified in one case. Surgery (one patient) and palliative ureteral diversion (one patient), respectively, led to death and end-stage renal failure. Successful dissolution of encrusted pyelitis was obtained in two patients treated with intravenous vancomycin and local acidification of the renal collecting system. Clinical observation shows that encrusted pyelitis is a threatening disorder that destroys the native kidneys and may lead to end-stage renal failure. Successful treatment of the disease by chemolysis and antibiotics depends on correct and early diagnosis. Diagnosis required recognition of the predisposing factors, computed tomography imaging of the urinary tract, crystalluria, and identification of urea-splitting bacteria with prolonged culture on selective medium.

Aged↗
PubMed1998

Nephrolithiasis.

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Calcium↗