whewellite and weddellite

Topics: Apatites; Calcium Compounds; Calcium Oxalate; Calcium Phosphates; History, 18th Century; History, 19th Century; History, 20th Century; Humans; Magnesium Compounds; Minerals; Names; Phosphates; Struvite; Urinary Calculi

To assess the potential of automated machine-learning methods for recognizing urinary stones in endoscopy.. Surface and section images of 123 urinary calculi (109 ex vivo and 14 in vivo stones) were acquired using ureteroscopes. The stones were more than 85% 'pure'. Six classes of urolithiasis were represented: Groups I (calcium oxalate monohydrate, whewellite), II (calcium oxalate dihydrate, weddellite), III (uric acid), IV (brushite and struvite stones), and V (cystine). The automated stone recognition methods that were developed for this study followed two types of approach: shallow classification methods and deep-learning-based methods. Their sensitivity, specificity and positive predictive value (PPV) were evaluated by simultaneously using stone surface and section images to classify them into one of the main morphological groups (subgroups were not considered in this study).. Using shallow methods (based on texture and colour criteria), relatively high sensitivity, specificity and PPV for the six classes were attained: 91%, 90% and 89%, respectively, for whewellite; 99%, 98% and 99% for weddellite; 88%, 89% and 88% for uric acid; 91%, 89% and 90% for struvite; 99%, 99% and 99% for cystine; and 94%, 98% and 99% for brushite. Using deep-learning methods, the sensitivity, specificity and PPV for each of the classes were as follows: 99%, 98% and 97% for whewellite; 98%, 98% and 98% for weddellite; 97%, 98% and 98% for uric acid; 97%, 97% and 96% for struvite; 99%, 99% and 99% for cystine; and 94%, 97% and 98% for brushite.. Endoscopic stone recognition is challenging, and few urologists have sufficient expertise to achieve a diagnosis performance comparable to morpho-constitutional analysis. This work is a proof of concept that artificial intelligence could be a solution, with promising results achieved for pure stones. Further studies on a larger panel of stones (pure and mixed) are needed to further develop these methods.

Topics: Artificial Intelligence; Cystine; Humans; Struvite; Uric Acid; Urinary Calculi

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

In order to understand the processes of stone formation, compositional, spectroscopic, mineralogical and crystallographic characteristics of human urinary stones collected from patients in Sri Lanka were investigated in detail. The data showed that the majority of urinary calculi were calcium oxalate, either whewellite or weddellite. Other solid phases of stones were composed of struvite, uricite and hydroxylapatite. However, mixed compositions were common except for whewellite stones which occur frequently in pure form. Scanning electron microscope observations and associated energy-dispersive X-ray analyses revealed that whewellite or weddellite was well crystalized compared to other stones types, while phosphate stones were mostly cryptocrystalline. The average δ

Topics: Calcium Oxalate; Female; Humans; Isotopes; Male; Minerals; Phosphates; Sri Lanka; Urinary Calculi

This study reports on a retrospective evaluation of epidemiological data from calcium oxalate stones in dogs differentiated into calcium oxalate monohydrate (Whewellite, Wh) and calcium oxalate dihydrate (Weddellite, Wd). Of the 22 456 uroliths submitted from 1979 to 2015, 6690 (29.8%) were composed of > 70% calcium oxalate. During the observation period, the proportion of calcium oxalate stones rose from 4% (1979) to 46% (2015). Of all the calcium oxalate stones, 31.0% were Wh and 49.4% Wd, while 19.6% were a mixture of Wh and Wd. The dogs with Wh stones were significantly older than the dogs with Wd stones. Several breeds have increased odds ratios (OR) for either Wh (5 highest OR: Norwich terrier, keeshond, Norfolk terrier, fox terrier, sheltie) or Wd (Pomeranian, borzoi, Japanese spitz, Finnish lapphund, bichon frise). Analytical differentiation of the calcium oxalate stones into Wh and Wd is important for understanding the cause and possible treatment and prevention of the uroliths.

Topics: Age Factors; Animals; Calcium Oxalate; Dog Diseases; Dogs; Female; Male; Nephrolithiasis; Retrospective Studies; Sex Factors; 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

Calcium oxalate is found in nature in three different crystalline states determined by the number of H2O in the unit formula (whewellite CaC2O4·H2O, COM; weddellite CaC2O4·(2+x)H2O, COD and caoxite CaC2O4·3H2O, COT). The properties of these materials are relevant in the field of biomedicine, cultural heritage and mineralogy. In two previous papers, we have used X-ray diffraction and vibrational spectroscopy (infrared and Raman) to derive information on crystal and molecular structures of COM and COD. In this paper, we complete the synthesis and analysis on the third form, COT, and present a comparative study of the data collected from the three crystalline states. The experiments clearly highlight the role played by the H2O molecules linked within the structure by different kinds of hydrogen bonds. The vibrational assignment of the infrared and Raman bands are critically proposed. The fact relevant for the work in biomedicine, cultural heritage and crystallography is that a simple examination of the spectra allows quickly to determine the chemical nature of the material in an unknown sample even in a minute quantity or in awkward experimental conditions.

Topics: Calcium Oxalate; Crystallization; Models, Molecular; Spectrophotometry, Infrared; Spectrum Analysis, Raman; Synchrotrons; X-Ray Diffraction

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

In this work 85337 urinary stones were analysed by X-ray diffraction in regard of their qualitative and quantitative composition. Urological practitioners and hospitals from all areas of the former FRG sent urinary stones to the Institute of Mineralogy in Bonn and to the Urology Department of the St Josef-Hospital in Troisdorf up to December 31st, 1994. The evaluations were carried out with special regard to the frequency of occurrence and to the quantity portions. The frequency of occurrence of one component describes the percentage of the urinary stones which contain this component. The quantity portion describes the average amount of one component in regard to all urinary stones which contain this component as well. The frequency of occurrence of whewellite was 75.77% and of wheddellite 46.41%. 34.25% of all calculi were monomineralic and 55.3% were bimineralic.

Topics: Adolescent; Adult; Age Factors; Aged; Apatites; Calcium Oxalate; Child; Child, Preschool; Cross-Sectional Studies; Crystallography, X-Ray; Female; Germany; Humans; Infant; Magnesium Compounds; Male; Middle Aged; Phosphates; Sex Factors; Struvite; Uric Acid; Urinary Calculi

We have extended our previous observation that the percent occurrence of calcium oxalate stones decreased while that of calcium phosphate stones increased with each new stone event.. The National VA Crystal Identification Center has analyzed veteran patient urinary tract stones from VA hospitals throughout the United States since 1983. We reviewed the composition of 33,198 stones with emphasis on the changes in composition. More than 11,786 stones came from 5,088 recurrent stone formers. Stones were analyzed using high resolution x-ray powder diffraction and Fourier transform infrared spectroscopic techniques. When the stones were investigated as a function of time, it was determined that there was greater variability when samples were more than 30 days apart.. The percent occurrence of whewellite, weddelite, apatite, brushite and uric acid in stones increased between 1.0% and 5.9% since our previous study. The percent occurrence of struvite decreased by 2.6%. The percent of calcium oxalate stones decreased while that of calcium phosphate stones increased with each new event. However, the total percent occurrence of all calcium containing stones did not significantly change with recurrent stone events.. Our study suggests a strong trend for the conversion of stone disease from calcium oxalate to calcium phosphate containing stones, which could influence the progression and severity of disease.

Topics: Apatites; Calcium Oxalate; Calcium Phosphates; Humans; Magnesium Compounds; Phosphates; Recurrence; Spectroscopy, Fourier Transform Infrared; Struvite; Uric Acid; Urinary Calculi; X-Ray Diffraction

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

Topics: Argentina; Cactaceae; Calcium Oxalate; Crystallization; Microscopy, Electron, Scanning; Minerals; Molecular Conformation; Opuntia; Spectroscopy, Near-Infrared

The aim of the present study, performed on typical Argiudolls in a natural reserve with little or no anthropic impact, was to characterize the fungous biomineralizing process of calcium oxalate crystals in organic horizons of the soil. The chosen sites possessed different plant cover, identified as acacia woods and grassy meadows with particular micro environmental conditions that have differing effects in the process of biomineralization. The contribution of the plant material in the soil is a key factor since 1) it generates the particular composition of the organic horizons, 2) it determines the nature of decomposing organisms, and 3) it affects the presence, composition and development of biominerals. According to the results obtained, the acacia woods prove to be a site comparatively more favorable to the fungous biomineralizing process. This makes itself manifest in the greater abundance and development of crystals in the organic horizons of the soil, resulting in whewellite (CaC2O4.H2O) and weddellite (CaC2O4.(2+x) H2O) regarding biomineral species developed, the latter being the major component. The observation of both species of biominerals is noteworthy since it represents the first cited in the country. The isolated fungous organisms were Trichoderma koningii, and Absidia corymbifera. T. koningii was identified as the most active biomineralizing organism thus constituting the first reference to indicate this species as a biomineral producing agent.

Topics: Acacia; Argentina; Calcium Oxalate; Crystallization; Fresh Water; Soil Microbiology; Trees; Trichoderma

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

Quantitative assessment of urinary calculus (renal stone) constituents by infrared analysis (IR) is hampered by the need of expert knowledge for spectrum interpretation. Our laboratory performed a computerized search of several libraries, containing 235 reference spectra from various mixtures with different proportions. Library search was followed by visual interpretation of band intensities for more precise semiquantitative determination of the composition. We tested partial least-squares (PLS) regression for the most frequently occurring compositions of urinary calculi. Using a constrained mixture design, we prepared various samples containing whewellite, weddellite, and carbonate apatite and used these as a calibration set for PLS regression. The value of PLS analysis was investigated by the assay of known artificial mixtures and selected patients' samples for which the semiquantitative compositions were determined by computerized library search followed by visual interpretation. Compared with that method, PLS analysis was superior with respect to accuracy and necessity of expert knowledge. Apart from some practical limitations in data-handling facilities, we believe that PLS regression offers a promising tool for routine quantification, not only for whewellite, weddellite, and carbonate apatite, but also for other compositions of the urinary calculus.

Topics: Apatites; Calcium Oxalate; Fourier Analysis; Humans; Quality Control; Regression Analysis; Retrospective Studies; Spectrophotometry, Infrared; Urinary Calculi

The internal-standard method and the powder diffractometer have been applied here to the quantitative determination of urinary stone constituents by x-ray diffraction (XRD). Reference intensity ratios determined for six stone substances were used in the reduction of intensity data. Constituent concentrations calculated for 21 stones were compared with values obtained from an element-sensitive technique. We conclude that XRD analysis alone cannot be regarded as a routine technique for the quantitative characterization of uroliths, but that semiquantitative XRD analysis supplemented by accurate quantitative elemental data is more suitable for the precise determination of true stone composition.

Topics: Calcium Oxalate; Calcium Phosphates; Durapatite; Humans; Hydroxyapatites; Magnesium; Magnesium Compounds; Phosphates; Struvite; Uric Acid; Urinary Calculi; X-Ray Diffraction

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

Topics: Calcium Oxalate; Humans; Hydrogen-Ion Concentration; Spectrophotometry, Infrared; Urinary Calculi

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

Topics: Calcium Oxalate; Humans; In Vitro Techniques; Spectrophotometry, Infrared; Urinary Calculi

Topics: Apatites; Calcium Oxalate; Differential Thermal Analysis; Humans; Urinary Calculi; X-Ray Diffraction

The occurrence of different hydrate forms derived from a single chemical compound results from the selective conditions of crystallization. Identification of the crystalline phases and the structural types of stones may provide the physician with important data concerning the etiopathogenesis of the complaint. The authors have studied the crystallization of calcium oxalate in an aqueous solution and the process of spontaneous crystalluria. They noted that whewellite resulted, in many cases, from a concentration of oxalate, and weddellite from a concentration of calcium. This article discusses the correlations between morphological types of oxalate stones, the localization of the stones in the urinary tract, the biological disorders noted, and the sex of the patients.

Topics: Calcium Oxalate; Crystallization; Humans; In Vitro Techniques; Structure-Activity Relationship; Urinary Calculi

Topics: Adult; Aged; Calcium Oxalate; Calcium Phosphates; Female; Humans; Hydroxyapatites; Magnesium; Magnesium Compounds; Male; Middle Aged; Phosphates; Struvite; Urinary Calculi; X-Ray Diffraction

Within the scope of the investigation of more than 1,500 urinary calculi by scanning electron microscopy (SEM), some peculiarities arose concerning secondary phase transitions and morphology of some of the crystalline phases present. There is evidence for a phase transition from Ca-oxalate dihydrate to the monohydrate form in oxalate rich stones. This is characterized by a transitional zone, in which often relatively large monocrystals of newly formed whewellite are found, sticking within weddellite crystals with typical dissolution signs. We conclude that the phase transformation is regulated by dissolution and recrystallization. In mixed uric acid / uric acid dihydrate stones, occasionally parallel growth of apparently two different kinds of crystals upon each other can be observed, which possibly are uric acid crystals grown epitaxially on uric acid dihydrate. A few nearly pure whewellite stones with little Ca-phosphate at the central core show tubules which obviously had been part of a calcified renal papilla and so had been acting as a nidus for stone formation. Bacterial footprints as well as calcified bacteria have only been found in apatite containing stones of patients with urinary tract infections by Escherichia coli. These bacteria are likely responsible for the origin of these footprints.

Topics: Calcinosis; Calcium Oxalate; Humans; Kidney Medulla; Microscopy, Electron, Scanning; Uric Acid; Urinary Calculi; 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

Texture examinations were made on 416 thin section and on 1,000 grain preparations of calcium oxalate calculi. The frequency of occurrence of four basic texture types in relation to pathological urine parameters, age and sex of the patients as well as types of stone removal are discussed. Percentage share of texture type I that correlates to hyperuricosuria shows a steady increase with increasing age. The proportions of types III and IV that are linked to hypercalciuria decrease with increasing age. The examinations show the feasibility of texture-type determinations within routine stone analysis and create the precondition for texture types to be included in metaphylaxis of calcium oxalate lithiasis.

Topics: Adult; Aged; Calcium Oxalate; Female; Humans; Male; Middle Aged; Urinary Calculi

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

X-ray powder diffraction, infrared spectroscopy and thermal analysis were used to study 108 stones that had been passed spontaneously from the upper urinary tract. The presence of apatite in pure calcium oxalate stones classified by x-ray diffraction was confirmed by infrared analysis of the ignited product. Consequently, 102 of 108 stones were found to be composed of weddellite and/or whewellite, and apatite. Besides the contents of weddellite, whewellite and apatite, the content of organic matrix also was estimated by thermal analysis in 102 stones, ranging from 1.1 to 17.2 per cent. The stones then were divided into 3 groups according to the principal constituent: 1) weddellite, 2) whewellite and 3) apatite. Weddellite stones were significantly heavier and significantly higher in apatite content than whewellite stones. It is suggested that weddellite calculi tend to become larger than whewellite stones. The apatite content was correlated with the ratio of weddellite to weddellite plus whewellite ( r equals 0.528), and the content of organic matrix was correlated with the whewellite content (r equals 0.708). Thus, it is considered that the weddellite-apatite and whewellite-organic matrix associations have important roles in the development and growth of weddellite and whewellite calculi, respectively.

Topics: Apatites; Calcium Oxalate; Cystine; Humans; In Vitro Techniques; Spectrophotometry, Infrared; Thermogravimetry; Uric Acid; Urinary Calculi; X-Ray Diffraction

Separate core and shell examinations were made on 10,000 urinary stones using a combined crystal-optical X-ray diffractometric method of analysis. 29.5% of these concrements showed differences in qualitative phases between central and peripheral stone parts. All the more frequent stone components were found in core and shell to the same extent. Only weddellite and uric acid dihydrate show a clear preference of the shell. Our method of analysis showed cores to be mostly monomineralic and peripheral stone parts mostly bimineralic. Consequences of this topographic stone analysis for metaphylaxis of urolithiasis are pointed out.

Topics: Apatites; Calcium Oxalate; Humans; Microscopy, Polarization; Minerals; Uric Acid; Urinary Calculi; X-Ray Diffraction

We studied the growth of calcium oxalate monohydrate (COM) crystals in stirred suspensions by following the changes in ionic conductivity of supersaturated solutions at 25 +/- 0.02C. At a pH of 6.9-7.2, in the presence of polyphosphate ion, crystallization proceeded by an initial rapid step followed by a markedly reduced growth rate as compared with that in pure supersaturated solution. The initial surge was reduced as the polyphosphate concentration reached 1.6 X 10(-6) M, which can be interpreted as evidence of either surface nucleation or the incomplete adsorption of inhibitor at the active growth sites. In spontaneous precipitation experiments made in the presence of polyphosphate ions, the formation of calcium oxalate dihydrate and trihydrate is favored together with appreciable coprecipitation of additive ions.

Topics: Adsorption; Calcium Oxalate; Chemical Phenomena; Chemistry; Crystallization; Polyphosphates

The influence of magnesium ions on the solubility and formation of calcium oxalate was studied. Both calcium oxalate mineral constituents of urinary calculi (whewellite and weddellite) were prepared in the presence of Mg2+ions. For preparation, a gel growth technique and precipitation in aqueous solutions were used. The metastable weddellite formed only when Mg2+ concentration, reaction, temperature and precipitation velocity (see text) were combined in the proper way. It is concluded that mg2+ions may induce an increase of solubility of calcium oxalate but in contrast also broaden the Ostwald Miers range, thus favouring the formation of larger crystals.

Topics: Calcium Oxalate; Crystallization; Ions; Magnesium; Urinary Calculi

Topics: Calcium Oxalate; Crystallization; Crystallography; Humans; Urinary Calculi

Apatite in some samples of common urinary calculi consisting mainly of apatite or of calcium oxalate and apatite was subjected to X-ray and thermal analysis and electron microscopic investigation. The X-ray analysis has determined the lattice parameters agreeing with hydroxyapatite, and the mean crystallite size normal to the basal plane in a range of 200-800 A. The thermal analysis is given by differential thermal analysis (DTA) and thermogravimetric (TG) curves. From the TG curve of a mixed apatite-calcium oxalate calculus, an approach is given to estimate the proportions of the constituent materials; the result is as follows: whewellite, 51.7%; weddellite, 16.6%; apatite, 19.1%; and organic materials, 12.6%. Analysis with the scanning electron microscope with energy dispersive X-ray spectrometer has shown that apatite is found as tiny spherules (5-10 micrometer in diameter) with fluffy surfaces resulting from projecting fine fibers or needles (about 0.5 micrometers in length). The fibers are considered to be mosaic aggregates of crystallites. The spherules fill interspaces of well-formed oxalate crystals or are included sporadically in individual crystals. Occasionally well-formed crystal-shaped oxalates are bordered with narrow bands consisting of apatite spherules (often as hemispheres) linked in a row.

Topics: Apatites; Calcium Oxalate; Crystallography; Hot Temperature; Humans; Microscopy, Electron; Surface Properties; Thermogravimetry; Urinary Calculi; X-Ray Diffraction

Postmortem scanning electron microscopy of human phalanges in a chronic uremic hemodialysis patient with hyperparathyroidism showed the presence of confluence abnormal rounded formations with a radial rosette-like crystalline pattern in the diaphysis as well as in the epiphyseal part of the bones. These fan-shaped configurations were found either as individual formations within bone trabeculae or as numerous aggregated crystalline deposits replacing large parts of the bone structure. The microdissected content of such large areas submitted to X-ray diffraction analysis revealed the predominant presence of calcium oxalate monohydrate or whewellite with some traces of hydroxyapatite. Oxalate titration analysis indicated the presence of 25% of oxalate, corresponding to 45% in weight of whewellite.

Topics: Adult; Calcium Oxalate; Chronic Kidney Disease-Mineral and Bone Disorder; Crystallography; Female; Fingers; Humans; Hydroxyapatites; Male; Microscopy, Electron, Scanning; Uremia; X-Ray Diffraction

We studied the growth of calcium oxalate dihydrate crystals (weddellite) in simulated urine and its transformation into the more stable monohydrate (whewellite). Sodium copper chlorophyllin in a concentration of 100 microgram per ml inhibited the growth of calcium oxalate dihydrate crystals in simulated urine. The size distribution parameters of the dihydrate crystals in the presence and absence of chlorophyllin suggest that soluble chlorophyllin could be of clinical significance in calcium oxalate urolithiasis.

Topics: Calcium Oxalate; Chlorophyll; Chlorophyllides; Crystallization; In Vitro Techniques; Microscopy, Electron, Scanning; Urinary Calculi

Scanning electron microscopy of calcium oxalate stones indicates a zonary structure of the Weddellite crystals of urine concrements which is due to concentration-dependent growth oscillations representing the precipitation of various calcium oxalate hydrates. In addition to the phenomenological demonstration of Weddellite crystal shapes, incubation experiments with different solutions give rise to the postulation of a dehydration process of primary Weddellite crystals via dissolution and recrystallization to Whewellite. The solvent attack starts at energetically preferred corners, edges and lattice disorders of the Weddellite crystals. The Weddellite-stabilizing role of urinary Mg ions is emphasized.

Topics: Calcium Oxalate; Crystallization; Humans; Microscopy, Electron, Scanning; Urinary 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