whewellite and Kidney-Calculi

This study describes the primary characteristics of the selected kidney stones surgically removed from the patients at the Mersin University Hospital in the southern Turkey and interprets their formation via petrographic, geochemical, XRD, SEM-EDX, and ICP-MS/OES analyses. The analytical results revealed that the kidney stones are composed of the minerals whewellite, struvite, hydroxyapatite, and uric acid alone or in different combinations. The samples occur in staghorn, bean-shaped composite, and individual rounded particle shapes, which are controlled by the shape of the nucleus and the site of stone formation. The cross-section of the samples shows concentric growth layers due to variations in saturation, characterizing the metastable phase. Kidney stone formation includes two main stages: (i) nucleation and (ii) aggregation and/or growth. Nucleation was either Randall plaque of hydroxyapatite in tissue on the surface of the papilla or a coating of whewellite on the plaque, or crystallization as free particles in the urine. Subsequently, aggregation or growth occurs by precipitation of stone-forming materials around the plaque or coating carried into the urine, or around the nucleus formed in situ in the urine. Urinary supersaturation is the main driving force of crystallization processes; and is controlled by many factors including bacterially induced supersaturation.

Topics: Humans; Hydroxyapatites; Kidney Calculi; Turkey; Urolithiasis

To predict the main component of pure and mixed kidney stones using dual-energy computed tomography and machine learning.. 200 kidney stones with a known composition as determined by infrared spectroscopy were examined using a non-anthropomorphic phantom on a spectral detector computed tomography scanner. Stones were of either pure (monocrystalline, n = 116) or compound (dicrystalline, n = 84) composition. Image acquisition was repeated twice using both, normal and low-dose protocols, respectively (ND/LD). Conventional images and low and high keV virtual monoenergetic images were reconstructed. Stones were semi-automatically segmented. A shallow neural network was trained using data from ND1 acquisition split into training (70%), testing (15%) and validation-datasets (15%). Performance for ND2 and both LD acquisitions was tested. Accuracy on a per-voxel and a per-stone basis was calculated.. Main components were: Whewellite (n = 80), weddellite (n = 21), Ca-phosphate (n = 39), cysteine (n = 20), struvite (n = 13), uric acid (n = 18) and xanthine stones (n = 9). Stone size ranged from 3 to 18 mm. Overall accuracy for predicting the main component on a per-voxel basis attained by ND testing dataset was 91.1%. On independently tested acquisitions, accuracy was 87.1-90.4%.. Even in compound stones, the main component can be reliably determined using dual energy CT and machine learning, irrespective of dose protocol.. • Spectral Detector Dual Energy CT and Machine Learning allow for an accurate prediction of stone composition. • Ex-vivo study demonstrates the dose independent assessment of pure and compound stones. • Lowest accuracy is reported for compound stones with struvite as main component.

Topics: Algorithms; Calcium Oxalate; Calcium Phosphates; Cysteine; Humans; Kidney Calculi; Machine Learning; Neural Networks, Computer; Phantoms, Imaging; Struvite; Tomography Scanners, X-Ray Computed; Tomography, X-Ray Computed; Uric Acid; Urinary Calculi; Xanthine

Previous studies have shown that split-bolus protocols in virtual non-contrast (VNC) reconstructions of dual-energy computed tomography (DE-CT) significantly decrease radiation dose in patients with urinary stone disease. To evaluate the impact on kidney stone detection rate of stone composition, size, tube voltage, and iodine concentration for VNC reconstructions of DE-CT.. In this prospective study, 16 kidney stones of different sizes (1.2-4.5 mm) and compositions (struvite, cystine, whewellite, brushite) were placed within a kidney phantom. Seventy-two scans with nine different iodine contrast agents/saline solutions with increasing attenuation (0-1400 HU) and different kilovoltage settings (70 kV/150 kV; 80 kV/150 kV; 90 kV/150 kV; 100 kV/150 kV) were performed. Two experienced radiologists independently rated the images for the presence and absence of stones. Multivariate classification tree analysis and descriptive statistics were used to evaluate the diagnostic performance.. Classification tree analysis revealed a higher detection rate of renal calculi > 2 mm in size compared with that of renal calculi < 2 mm (84.7%; 12.7%; p < 0.001). For stones with a diameter > 2 mm, the best results were found at 70 kV/Sn 150 kV and 80 kV/Sn 150 kV in scans with contrast media attenuation of 600 HU or less, with sensitivity of 99.6% and 96.0%, respectively. A higher luminal attenuation (> 600 HU) resulted in a significantly decreased detection rate (91.8%, 0-600 HU; 70.7%, 900-1400 HU; p < 0.001). In our study setup, the detection rates were best for cystine stones.. Scan protocols in DE-CT with lower tube current and lower contrast medium attenuation show excellent results in VNC for stones larger than 2 mm but have limitations for small stones.. • The detection rate of virtual non-contrast reconstructions is highly dependent on the surrounding contrast medium attenuation at the renal pelvis and should be kept as low as possible, as at an attenuation higher than 600 HU the VNC reconstructions are susceptible to masking ureteral stones. • Protocols with lower tube voltages (70 kV/Sn 150 kV and 80 kV/Sn 150 kV) improve the detection rate of kidney stones in VNC reconstructions. • The visibility of renal stones in virtual non-contrast of dual-energy CT is highly associated with the size, and results in a significantly lower detection rate in stones below 2 mm.

Topics: Calcium Oxalate; Calcium Phosphates; Contrast Media; Cystine; Humans; Image Processing, Computer-Assisted; Iodine; Kidney Calculi; Phantoms, Imaging; Prospective Studies; Radiation Dosage; Struvite; Tomography, X-Ray Computed; Urinary Calculi

We present in this paper accurate and reliable Raman and IR spectral identification of mineral constituents in nine samples of renal calculi (kidney stones) removed from patients suffering from nephrolithiasis. The identified mineral components include Calcium Oxalate Monohydrate (COM, whewellite), Calcium Oxalate Dihydrate (COD, weddellite), Magnesium Ammonium Phosphate Hexahydrate (MAPH, struvite), Calcium Hydrogen Phosphate Dihydrate (CHPD, brushite), Pentacalcium Hydroxy Triphosphate (PCHT, hydroxyapatite) and Uric Acid (UA). The identification is based on a satisfactory assignment of all the observed IR and Raman bands (3500-400c m(-1)) to chemical functional groups of mineral components in the samples, aided by spectral analysis of pure materials of COM, MAPH, CHPD and UA. It is found that the eight samples are composed of COM as the common component, the other mineral species as common components are: MAPH in five samples, PCHT in three samples, COD in three samples, UA in three samples and CHPD in two samples. One sample is wholly composed of UA as a single component; this inference is supported by the good agreement between ab initio density functional theoretical spectra and experimental spectral measurements of both sample and pure material. A combined application of Raman and IR techniques has shown that, where the IR is ambiguous, the Raman analysis can differentiate COD from COM and PCHT from MAPH.

Topics: Calcium Oxalate; Calcium Phosphates; Durapatite; Humans; Kidney Calculi; Magnesium Compounds; Phosphates; Spectroscopy, Fourier Transform Infrared; Spectrum Analysis, Raman; Struvite; Uric Acid

Determine stones composition of the upper urinary tract in the eastern region of Algeria.. Our study focuses on a set of 359 stones of the upper urinary tract collected between January 2007 and December 2012 at hospitals in the eastern region of Algeria and analyzed by Fourier transform infrared spectroscopy.. The male/female ratio was only 1.32. Calcium oxalate prevailed in 68.5% of stones and 49.3% of nuclei, mainly as whewellite (51.8% of stones and 37.9% of nuclei vs 16.7% and 11.4% respectively for weddellite). Carbapatite prevailed in 15% of stones and 29.8% of nuclei. The struvite, identified in 11.1% of calculi, prevailed in 3.9% of stones and 3.1% of nuclei. Among purines, uric acid prevailed with frequencies quite close to 8.9% and 7% respectively in the stone and in the nucleus while the ammonium urate prevailed in only 0.3% of stones and 3.3% of nuclei. The cystine frequency was 3.6% in both stone and nucleus. The frequency of stone with umbilication was 26.2%. Whewellite was the main component of umbilicated stones with Randall's plaque.. Our results suggest that stones of the urinary tract in the Algerian east region resemble those observed in industrialized countries. Some features such as stones location, the whewellite prevalence, the frequencies of main components in both the stone and the nucleus as well as the formation of stones on renal papilla confirm this trend.. 4.

Topics: Adult; Aged; Algeria; Antioxidants; Apatites; Calcium Oxalate; Female; Hemostatics; Hospitals; Humans; Kidney Calculi; Magnesium Compounds; Male; Middle Aged; Phosphates; Prevalence; Retrospective Studies; Risk Factors; Sex Distribution; Spectroscopy, Fourier Transform Infrared; Struvite; Uric Acid

The outpatient forensic aftercare department of the Charité Berlin treated 32 paraphilic sex offenders with GnRH analogues within the past 5 years. Out of those patients, three men suffered from urolithiasis and were in need of treatment. All 3 patients had previously developed osteopenia/osteoporosis while on antiandrogen treatment.This article describes these 3 cases and suggests an intense consideration of the possible occurrence of urolithiasis in sex offenders on antiandrogen treatment.

Topics: Adult; Calcium Oxalate; Cyproterone Acetate; Delayed-Action Preparations; Follow-Up Studies; Gonadotropin-Releasing Hormone; Humans; Kidney Calculi; Leuprolide; Long-Term Care; Male; Middle Aged; Paraphilic Disorders; Recurrence; Triptorelin Pamoate; Ureteral Calculi; Urolithiasis

This study aimed to assess the accuracy of low-dose dual-energy computed tomography (DECT) in predicting the composition of urinary calculi.. A total of 52 patients with urinary calculi were scanned with a 128-slice dual-source DECT scanner by use of a low-dose protocol. Dual-energy (DE) ratio, weighted average Hounsfield unit (HU) of calculi, radiation dose, and image noise levels were recorded. Two radiologists independently rated study quality. Stone composition was assessed after extraction by Fourier transform infrared spectroscopy (FTIRS). Analysis of variance was used to determine if the differences in HU values and DE ratios between the various calculus groups were significant. Threshold cutoff values to classify the calculi into separate groups were identified by receiver operating characteristic curve analysis.. A total of 137 calculi were detected. FTIRS analysis differentiated the calculi into five groups: uric acid (n=17), struvite (n=3), calcium oxalate monohydrate and dihydrate (COM-COD, n=84), calcium oxalate monohydrate (COM, n=28), and carbonate apatite (n=5). The HU value could differentiate only uric acid calculi from calcified calculi (p<0.001). The DE ratio could confidently differentiate uric acid, struvite, calcium oxalate, and carbonate apatite calculi (p<0.001) with cutoff values of 1.12, 1.34, and 1.66, respectively, giving >80% sensitivity and specificity to differentiate them. The DE ratio could not differentiate COM from COM-COD calculi. No study was rated poor in quality by either of the observers. The mean radiation dose was 1.8 mSv.. Low-dose DECT accurately predicts urinary calculus composition in vivo while simultaneously reducing radiation exposure without compromising study quality.

Topics: Adult; Apatites; Calcium Oxalate; Female; Humans; Image Interpretation, Computer-Assisted; Kidney Calculi; Magnesium Compounds; Male; Middle Aged; Phosphates; Prospective Studies; Radiation Dosage; Struvite; Tomography, X-Ray Computed; Ureteral Calculi; Uric Acid; Waist Circumference; Young Adult

Studies that evaluate the effect of age and gender on the stone composition are scarce. The aim of this study is to highlight the modification of epidemiological characteristics of this pathology according to patients' sex and age.. We studied 1269 urolithiasic patients ranging from 6 months to 92 years old and known as having urinary stones (752 males and 517 females). Stone analysis was performed respectively using a stereomicroscope and infrared spectroscopy to determine, respectively, the morphological type and molecular composition of each.. The annual average incidence of new stone formation was 30.25 per 100,000 inhabitants. In 1041 patients (81%), calculi were located in the upper urinary tract. Children and old man were more affected by bladder stone. Calcium oxalate monohydrate remains the most frequent stone component even if its frequency fell according to age (63.2% in teenagers and 40.6% in elderly [p<0.05]) in favour of the increase of uric acid stones (3,5% in teenagers and 41.5% in elderly [p<0.05]). Struvite stones were rare (3.5%) and more frequent in children.. The analysis of these data shows that urinary stones in Tunisia are tending to evolve in the same direction as in industrialized countries.

Topics: Adolescent; Adult; Age Distribution; Age of Onset; Aged; Aged, 80 and over; Calcium Oxalate; Child; Child, Preschool; Developing Countries; Female; Humans; Incidence; Infant; Kidney Calculi; Magnesium Compounds; Male; Middle Aged; Phosphates; Retrospective Studies; Sex Distribution; Social Change; Spectrophotometry, Infrared; Struvite; Tunisia; Uric Acid; Young Adult

Cystine stones are produced by an inherited disorder of the transport of amino acid cystine that results in excess of cystine in the urine (cystinuria). Cystine calculi in urinary tract present a significant problem in patients. We have recorded that cystine calculi are very uncommon in our region. Cystine crystals are unusually identified in the urinary deposits. The problem of recognizing cystine by FTIR as a component in mixture of stones is significant. The problem is compounded by the similarity of wavelengths of cystine with that of whewellite and uric acid. The objective of this paper is to elucidate the problems of identifying cystine in stone analysis and identifying a solution to get over this deficiency. Out of 1,300 urinary stones analysed by ordinary wet chemical methods and infrared spectroscopy, 30 stone samples, which were reported to have cystine peaks in significant numbers, were selected. These samples were powdered, mixed with potassium bromide, pelletized and taken up for FTIR analysis. The wavelength patterns were scrutinized by comparing with the peaks obtained by the reference standards of cystine. Spectra were also obtained from pure cystine. Comparison of spectra with those of whewellite and uric acid was performed. Then the samples were taken for Scanning electron microscopy with elemental distribution analysis X-ray (SEM-EDAX). The samples were made conductive by gold sputtering and were fed into JEOL JSM 35 C SEM machine. Morphology was recorded by taking photographs. Further elemental distribution analysis (EDAX) was carried out to identify the elemental composition. Of the 30 samples taken up for FTIR analysis, all showed spectra identifiable with the reference peaks for cystine. However, when these peaks were compared with those of whewellite and uric acid, all the stone samples showed duplication of peaks for whewellite and uric acid and whewellite. The pure cystine spectra showed identifiable peaks are in the range of 3026, 1618.28, 1485, 846.75 cm(-1), etc. (from the standard spectrum of pure cystine). All the analysis findings were correlated with EDAX findings. On doing EDAX, we could separately find out the components present in a mixture. Three stones contained elemental pattern to fit with those of cystine. Even though it is difficult to find out the presence of cystine molecule in FTIR, it is possible to recognize it through EDAX and will be possible to confirm the presence of cystine in mixed urinary stones.

Topics: Calcium Oxalate; Cysteine; Humans; Kidney Calculi; Spectroscopy, Fourier Transform Infrared; Uric Acid

Calculi from 45 Moroccan children aged between 2 and 15 years underwent morphological and infrared spectrometric analysis. The stones were three times more frequent in males than females (M/F = 3.09). Whewellite was the main component in 51.1% of cases and in 44.4% of stone nuclei, wheddellite in 8.9% of stones and nuclei, carbapatite in 6.7% of stones and 8.9% of nuclei, struvite in 15.6% of stones and 11.1% of nuclei. Ammonium hydrogen urate and uric acid were predominant respectively in 8.9% and 6.7% of stones and in 15.6% and 11.1% of nuclei. In addition to whewellite, struvite and ammonium hydrogen urate were the main components of bladder stones from both sexes. With respect to their calculi, whewellite was present in 84.4% of cases and wheddellite in 26.7%. Purines were present in 46% of calculi, especially as ammonium urate (28.9%) and uric acid (15.6%). Calcium phosphates as the main components were infrequent. In contrast, they were frequently identified in urinary calculi from children, respectively 64.4% and 40% for carbapatite and amorphous carbonated calcium phosphate.

Topics: Adolescent; Calcium Oxalate; Child; Child, Preschool; Female; Humans; Kidney Calculi; Male; Morocco; Purines; Quaternary Ammonium Compounds; Sex Factors; Spectroscopy, Near-Infrared; Uric Acid

In regard to identify the compositions of urinary stones, the infrared spectra is a contemporary routine method. However, it is difficult to detect the absorption of carbonate in struvite stone by infrared spectra, because NH4 absorption of magnesium ammonium phosphate overlaps CO3 absorption of carbonate at 1420-1435 cm-1. With the purpose of demonstrating the existence of carbonate in struvite stones, the analysis of these stones by means of Raman spectra has been tried.. Forty urinary stones, the chemical compositions of which were previously determined by infrared spectroscopy, were submitted to Raman spectrum analysis, and subsequently to analysis by x-ray diffraction.. Thirty of 40 urinary stones were found to be composed of struvite and of mixed struvite-calcium oxalate by infrared analysis. Twelve of these stones were shown to have Raman spectra of magnesium ammonium phosphate, and the other stones to have spectra of apatite. By x-ray diffraction magnesium ammonium phosphate crystals were detected in 25 of these struvite stones and hydroxyl-apatite in another 3, and 2 cases were undeterminable. For other components, such as calcium oxalate, uric acid and cystine, the analytical results of infrared spectra coincided with those of Raman spectra and x-ray diffraction. Carbonate was detected in only a part of one struvite stone by Raman spectra.. Above-mentioned results may indicate that carbonate is only a minor component of urinary stones. Therefore, most of 1420-1435 cm-1 bands on the infrared spectra of struvite stones do not indicate CO3 absorption of carbonate, but NH(4) absorption of magnesium ammonium phosphate.

Topics: Calcium Oxalate; Carbonates; Female; Hemostatics; Humans; Kidney Calculi; Magnesium Compounds; Male; Phosphates; Spectrophotometry, Infrared; Spectrum Analysis, Raman; Struvite; Urinary Calculi; X-Ray Diffraction

The morphological and constitutional analysis of renal stone fragments expelled after extracorporeal shock wave lithotripsy enables the structure and morphological type of stones to be reconstructed in 92.8 per cent of the cases as regards surface and section and in 74.5 per cent of the cases down to the core. A study of the molecular and crystalline composition of such fragments demonstrated the preponderance of whewellite in both sexes (men 85.4 per cent; women 72.4 per cent). The frequency of weddellite was 1.6 times higher in men (73.8 per cent) than in women (44.8 per cent), and the frequencies of struvite and ammonium urate were 2.8 and 2.6 times respectively higher in women than in men, despite a significant fall in frequency as compared to a previous series. Correlations between morphological type of stone and biochemical data (when available) could be established in 84 per cent of the cases. This made it possible to initiate treatments aimed at preventing recurrences, the cost of these treatments in the long term being lower than that of the curative urological treatments, including extracorporeal shock wave lithotripsy.

Topics: Adult; Calcium Oxalate; Female; Hemostatics; Humans; Kidney Calculi; Lithotripsy; Magnesium; Magnesium Compounds; Male; Middle Aged; Phosphates; Struvite; Uric Acid

Piridoxilate is an association of glyoxylic acid and pyridoxine in which pyridoxine is supposed to facilitate in vivo transformation of glyoxylic acid to glycine rather than to oxalic acid. However, it has recently been shown that long-term treatment with piridoxilate may result in overproduction of oxalic acid and in calcium oxalate nephrolithiasis. We report a patient in whom piridoxilate induced both oxalate nephrolithiasis and chronic oxalate nephropathy with renal insufficiency, an association that has not been previously described. Therefore, piridoxilate should be added to the list of chemicals responsible for chronic oxalate nephropathy.

Topics: Aged; Calcium Oxalate; Glyoxylates; Humans; Kidney Calculi; Male; Nephrocalcinosis; Pyridoxine

One thousand and two calculi, which occurred in both black and white patients during a 15-year period, have been analysed by the X-ray diffraction technique. Calcium oxalate calculi were the most common irrespective of race. Whewellite calculi were equally distributed in both race groups, while weddelite stones appeared to be much less common amongst blacks; the opposite applied for struvite and the rare ammonium acid urate stones. The other calculi were approximately equally distributed between the two race groups. A statistically significant rising trend in the prevalence of renal stones in blacks, accompanied by changes in the ratios of the major stone forming constituents, have been a prominent feature of this survey. However, the aforementioned remained unchanged in white patients. Contrary to previous impressions, total urates exceed phosphates in whites as a major stone forming constituent. The composition of upper urinary tract stones in blacks, during the 3-year period 1981 to 1983, was very similar to the composition previously reported for the Sudanese. The profile of renal stones in blacks over the last 3 years, however, is now becoming substantially different from that of the other previously reported surveys and may be approaching that of their white compatriots. A change in the dietary patterns in blacks is occurring which is also reflected in an increasing incidence of ischaemic heart disease and which may also be responsible for the observed changes in renal stones.

Topics: Black or African American; Black People; Calcium Oxalate; Humans; Kidney Calculi; Phosphates; South Africa; Uric Acid

During the last 4 years we collected 27 specimens of calcium oxalate nephrolithiasis in patients receiving long-term treatment with piridoxilate, a drug composed of an equimolar combination of glyoxylate and pyridoxine. The mean duration of treatment was 3.6 years (range 4 months to 10 years) and the mean daily dose was 580 mg. piridoxilate, which contained 160 mg. glyoxylate. Calculi often recurred, with an average number of 9.9 per patient, and an open operation, shock wave lithotripsy or percutaneous nephrolithotomy was required in 22 patients (81 per cent). Oxalate excretion was 727 +/- 246 mumol. per day while on the drug and 382 +/- 201 mumol. per day after the drug was withdrawn. Whewellite was the major component of calculi in all cases but the stones exhibited a peculiar morphological arrangement, with multiple small indentations and a fine mamillary structure. Freshly voided urine specimens contained unusual crystals, which on infrared spectroscopy were composed of calcium oxalate trihydrate, a variety of crystal never observed previously in human urine. Piridoxilate-induced calcium oxalate nephrolithiasis is a new variety of metabolic drug-induced nephrolithiasis. Our observations suggest that even large doses of pyridoxine may be unable to prevent the excessive production of oxalate from glyoxylate.

Topics: Adult; Aged; Calcium Oxalate; Coronary Disease; Female; Humans; Hyperoxaluria; Kidney Calculi; Male; Middle Aged; Pyridoxine; Time Factors

In 43 healthy reference persons and 54 patients with relapsing calcium oxalate nephrolithiasis the absorption of oxalic acid was measured by means of 14C-oxalic acid. In patients with oxalate calculi the absorption of oxalic acid is totally increased and also in such ones with Whewellite-calculi. It is decreased in carriers of Weddelite calculi. The increase of the absorption of oxalic acid in patients with mixed calculi is not significant.

Topics: Adult; Calcium; Calcium Oxalate; Female; Humans; Kidney Calculi; Kidney Tubules; Magnesium; Male; Middle Aged; Oxalates; Oxalic Acid; Recurrence

The effects of synthetic urine environments of pH 4, 6, and 9.5 on the microhardness of renal calculi have been investigated. Tests were made, using both Vickers and Knoop indenters, on three compositions of calculi: 100% calcium oxalate monohydrate (whewellite), 100% uric acid, and 98% magnesium ammonium phosphate hexahydrate (struvite) mixed with 2% carbonate apatite. Whewellite calculi hardness was lowered, relative to (dry) values by 45-55% when saturated with a solution of pH 9.5. Exposure to lower pH conditions was not as effective in lowering hardness in this case. Struvite calculi hardness was lowered by 41-52% compared to the dry hardness and uric acid calculi hardness decreased by 25-36%, compared to dry hardnesses. For uric acid stones the reduction in hardness did not depend on pH within the range of pH values investigated. For struvite stones, acid pH conditions appear to give an increased softening, compared to other pH values.

Topics: Biomechanical Phenomena; Calcium Oxalate; Humans; Hydrogen-Ion Concentration; In Vitro Techniques; Kidney Calculi; Magnesium; Magnesium Compounds; Phosphates; Struvite; Uric Acid

A total of twelve human kidney stones, composed almost exclusively of uric acid, whewellite and organic matrix were initially studied by x-ray (powder; single crystal), scanning and transmission electron diffraction techniques prior to as well as after exposure to 0.25 M EDTA solutions (96 hours; pH 7.1). Subsequent high-resolution scanning ion probe analyses eventually detected a phosphate phase not resolved by any of those techniques. Templates of organic matter lay above and in between the radial striations of whewellite. Often juxtaposing sets of striations are not in correct register with respect to one another. A sharp transition exists in the cores of the stones and separates an area characterized by the random deposition of whewellite from one in which the latter commences to grow in the form of radial striations. This transition is expected to be mediated by a physico-chemical and/or structural control. In laminae of organic matrix sectioned from EDTA-untreated cores well developed spherules are detected. Those superimpose on a substrate characterized by a considerable degree of crosslinking. Maximum spherule width is of the order of 0.8 micron. There is evidence of deposition in between the spherules. That deposition pattern appears to be controlled by the morphology and location of the spherules, thus suggesting that it is secondary to spherule formation.

Topics: Calcium Oxalate; Edetic Acid; Humans; Kidney Calculi; Microscopy, Electron; Uric Acid; Urinary Bladder Calculi; X-Ray Diffraction

The investigation of the degree of interpenetration between the two component phases of whewellite kidney stones, the protein matrix and calcium oxalate monohydrate crystallites, is extended by a technique of microchemical analysis, employing X-ray photoelectron spectroscopy (XPS). The technique involves determining the surface elemental (hence chemical) composition of fractured whewellite stones. Comparison with the bulk composition of about 95% COM and 5% matrix yielded information on the fracture path, hence on the spatial distribution of the two phases. The results showed large increases in matrix signal upon fracture, confirming that the minor phase, matrix, which is expected to provide an easy path for fracture, pervades the structure down to the level of individual crystallites.

Topics: Calcium Oxalate; Crystallization; Electron Probe Microanalysis; Humans; Kidney Calculi; Microscopy, Electron; Spectrophotometry, Infrared; Surface Properties

Human kidney stones, composed almost exclusively of uric acid and whewellite, were studied using x-ray (powder and single-crystal) as well as scanning electron-diffraction techniques. Whewellite--showing as a concentric aggregate characteristically marked by radial striations--is enclosed within a mass of uric acid, the crystallites of which grow with their b axis parallel to the radial direction of the striations. That axis corresponds to b (2 X 7.294 A) and tends to systematically superimpose over its uric acid counterpart (b = 7.40 A). Nonetheless no other such dimensional match was found for the other set of periodicities that characterize the uric acid whewellite interfaces, raising questions that a systematic epitaxial interaction could there take place. Selected uric acid-whewellite contacts and the crucial role of the "matrix" were also investigated.

Topics: Calcium Oxalate; Crystallization; Humans; Kidney Calculi; Microscopy, Electron, Scanning; Uric Acid; X-Ray Diffraction

From 3000 urinary calculi analysis, a morphological classification allowed us to appoint 7 structural types of oxalate stones, dependent on whewellite or/and weddellite. We observed evidence for correlations between biological data and these structural types, mainly between types I and hyperoxaluria, types II and hypercalciuria, types II + IV or IV and hyperparathyroïdism, as well as between whewellite and hyperuricuria. We determined in vitro calcium and oxalate concentrations ranges to crystallize various hydrate forms of calcium oxalate and we observed that whewellite form is almost the only one fitted for crystallizing in renal papilla. From this various data, it results that, in vivo, whewellite is dependent on oxalate concentration whereas weddellite is rather dependent on calcium concentration. Otherwise, differences in occurrence of morphological types of oxalate calculi were observed as a function of the patient' sex, the urinary tract localisation of calculi, or the crystalluria.

Topics: Calcium; Calcium Oxalate; Crystallization; Humans; Hyperparathyroidism; Kidney Calculi; Kidney Medulla; Oxalates; Uric Acid

The mineral composition of 103 stones from Iran was determined by a polarisation microscope and infrared spectroscopy. The commonest components were whewellite (81.5%), weddellite (40.7%), apatite (69%) and ammonium acid urate (24.4%). Ectopic cossification in the nuclei was found in three renal calculi (2.9%). Twenty-five stones were from children, where one of the most frequent patterns was formed by both ammonium acid urate and calcium oxalate. This suggests that a high proportion of the children from Iran with urolithiasis have nutritional disorders.

Topics: Adult; Calcium Oxalate; Calcium Phosphates; Child; Female; Humans; Hydroxyapatites; Iran; Kidney Calculi; Magnesium; Magnesium Compounds; Male; Microscopy, Polarization; Minerals; Phosphates; Spectrophotometry, Infrared; Struvite; Uric Acid; Urinary Bladder Calculi

A large number of trace elements has been found in calcium stones (whewellite, weddellite, and apatite) and in struvite. Significantly fewer elements, with lower abundances, are found in uric acid and cystine. With the exception of four trace elements (lead, silicon, strontium, and zine), the trace element assemblages are identical in the oxalates (whewellite and weddellite); struvite is also similar but with notable exceptions. In general, apatite contains approximately twice the level of trace element abundances as do the oxalates. This study is based on the distribution of 20 elements in 186 mimeralogically identified urinary calculi from three generalized areas of the United States (northeast, southeast, and midwest). In general, there is no statistical difference in the trace element assemblages of mineralogically identical stones from the three areas.

Topics: Aluminum; Apatites; Calcium; Calcium Oxalate; Cystine; Humans; Kidney Calculi; Magnesium; Oxalates; Phosphates; Quaternary Ammonium Compounds; Silicon; Trace Elements; United States; Uric Acid; Zinc