whewellite and Urinary-Calculi

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

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

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

Incidence of pediatric urolithiasis is decreasing in most developing countries where endemic bladder stones are less prevalent than in the past years. In parallel, stone composition has changed. Only few data are available in North Africa, except for Tunisia. We report stone composition in the Moroccan pediatric population.. Composition of 432 stones from children (302 boys, 130 girls) was determined by infrared spectroscopy. The samples were collected during the period 1999-2016. Stone morphology, which is an important aspect for etiology was determined by examination of each stone under a stereomicroscope. Stone composition was compared to patients' age and gender.. The global male-to-female ratio was 2.32. Regarding stone composition, calcium oxalate was the main component in 51.6% of the stones, followed by struvite (18.1%), ammonium urate (9.5%) and carbapatite (9%). Significant differences were found between males and females: calcium oxalate accounted for 72.3% of stones in girls and 42.7% in boys (P<10. This is the largest series of pediatric stones in Morocco studied by infrared analysis and morphological examination.. 3.

Topics: Adolescent; Age Factors; Apatites; Calcium Oxalate; Child; Child, Preschool; Female; Humans; Incidence; Infant; Male; Morocco; Sex Factors; Spectrophotometry, Infrared; Struvite; Urinary Calculi; Urolithiasis

Urolithiasis is a frequent and in many cases serious disease. Proper analysis of kidney stone composition is crucial for appropriate treatment and prevention of disease recurrence. In this work, scanning electron microscopy (SEM) coupled with energy-dispersive spectroscopy was applied for a study of 30 samples covering the most common types of human kidney stones. The results are analyzed and evaluated in terms of applicability of the method for both routine kidney stone analysis as well as collecting of specific data. The method provides complex information about studied samples including morphology of the stones and of the present crystals or their aggregates. It also brings information on elemental composition of the phases. After application of standardization, quantitative microanalysis with detection limits of 400 ppm (Mg, P, S, Cl, K, Ca), 500 ppm (Na) and 1200 ppm (F) was obtained. Compositional mapping with EDS shows the elemental distribution within a sample. This study demonstrated that information on morphology and chemistry acquired by these methods was highly reliable for identification of phases, even when present in small amounts. It provided information on kidney stone structure, relationships between phases, major and minor element content, and variations in chemical composition related to the growth of the stones. SEM represents a powerful tool in urinary stone analysis, since a single facility can produce a wide spectrum of information. It can be suggested as a basic method used for routine urinary stone identification, whilst bringing additional detailed information that cannot be obtained by other methods.

Topics: Apatites; Calcium Oxalate; Calcium Phosphates; Humans; Microscopy, Electron, Scanning; Spectrometry, X-Ray Emission; 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

Monitoring of body burden of toxic elements is usually based on analysis of concentration of particular elements in blood, urine and/or hair. Analysis of these matrices, however, predominantly reflects short- or medium-term exposure to trace elements or pollutants. In this work, urinary stones were investigated as a matrix for monitoring long-term exposure to toxic and essential elements. A total of 431 samples of urinary calculi were subjected to mineralogical and elemental analysis by infrared spectroscopy and inductively coupled plasma mass spectrometry. The effect of mineralogical composition of the stones and other parameters such as sex, age and geographical location on contents of trace and minor elements is presented. Our results demonstrate the applicability of such approach and confirm that the analysis of urinary calculi can be helpful in providing complementary information on human exposure to trace metals and their excretion. Analysis of whewellite stones (calcium oxalate monohydrate) with content of phosphorus <0.6 % has been proved to be a promising tool for biomonitoring of trace and minor elements.

Topics: Adult; Age Factors; Aged; Aged, 80 and over; Calcium Oxalate; Czech Republic; Environmental Monitoring; Female; Geography; Humans; Male; Middle Aged; Sex Factors; Trace Elements; Urinary Calculi

The primary type 1 hyperoxaluria (HP1) is the most frequent and severe form of the primary hyperoxaluriae. It is related to an enzymatic deficit in alanine glyoxylate aminotransferase (AGT). It is a recessive autosomic disease. Rare in Europe, it is responsible for 13% of the end stage renal failure in the Tunisian child.. The aim of this work is to evaluate the biological and molecular examinations contributing with the early diagnosis and the follow-up of the HP1 patients and to test their response to pyridoxin.. A prospective study of 15 children who have oxaluria lower than 500 μmol/l and normal renal function is carried out. The cristalluria study, oxaluria and the glycolate-glycerate urinary ratio were carried out on all the patients. The so-called mutation maghrebean T853 (Ile244 Thr) was detected by direct sequencing of the exon 7 gene AGXT. The response to pyridoxin was tested among 13 patients.. The oxaluria concentration was greater or equal to 1000 μmol/l in nine cases (60%) and ranging between 600 and 1000 μmol/l in the remaining cases. The oxaluria flow was significantly high depending on the age. The glycolaturia was high among eight patients (57%). In 61,5% of the cases, the most frequent crystalline species was whewellite (C1). The "maghrebin" mutation was identified in nine patients at the heterozygous state, showing 25% allelic frequency. The response to pyridoxin was observed in the 13 tested cases.. The HP1 is frequent in our country from where the need for an early diagnosis. The use of simple biochemical tools such as the study of the cristalluria, the morphological analysis of stones and the oxaluria allow to direct the diagnosis towards a HP1, confirmed by the glycolaturia determination. The molecular biology is required in the atypical forms.

Topics: Adolescent; Calcium; Calcium Oxalate; Child; Child, Preschool; Consanguinity; Crystallization; Female; Gene Frequency; Humans; Hyperoxaluria, Primary; Infant; Male; Mutation; Oxalic Acid; Transaminases; Tunisia; Urinary Calculi

Primary hyperparathyroidism (HPT) is a common cause of urolithiasis. Only a few data are available on stone composition and morphology in HPT patients.. We compared the composition and morphology of stones from 264 HPT patients (143 males and 121 females) and 24 567 non-HPT stone formers (16 918 males and 7649 females) including a subgroup of 1356 patients with idiopathic hypercalciuria (IH) (1049 males and 307 females). We excluded uric acid and infection stones containing struvite.. Calcium oxalate (CaOx) was the most prevalent crystalline species among the main components of stones in all groups. However, CaOx stones were significantly less frequent in patients with vs without HPT (51.9% vs 82.2%; P<0.0001). An inversion of CaOx crystalline phases was observed in HPT and IH patients: whewellite was predominant in 16.3% and 30.2% of cases, respectively, vs 57.4% in the non-HPT group (P<0.001), whereas weddellite was predominant in 35.6% of HPT and 49.5% of IH vs 24.8% of non-HPT stones (P<0.0001). Among calcium phosphates, brushite was 7-fold more frequent in HPT than in non-HPT patients (14.0% vs 2.2%; P<0.0001) and almost three times as frequent as in IH patients (4.9%, P<0.0001). Carbapatite was significantly more frequent in male patients with HPT vs non-HPT or IH patients (23.1% vs 8.3% and 9.9%, P<0.0001). Morphological data showed that pure type I calculi were markedly less frequent in HPT patients (1.1% vs 25.3% in non-HPT group, P<0.0001, and 9.1% in IH subgroup, P<0.001). A high occurrence of IVd calculi and of the association of types IVa and II was observed in HPT vs non-HPT and IH patients (14.4%, 2.3% and 6.3%, P<0.0001 and 58.3%, 17.2% and 29.9%, P<0.0001, respectively).. Our data highlight a striking increase in the proportion of calcium-dependent crystalline species, especially brushite in HPT patients, with particular morphological associations in both genders which were more marked than in IH patients.

Topics: Adult; Apatites; Calcium Oxalate; Calcium Phosphates; Female; Humans; Hyperparathyroidism, Primary; Male; Middle Aged; Predictive Value of Tests; Urinary Calculi

Several modalities of stone analysis are utilised in different laboratories. However, the treating clinician finds it hard to assess the initiation and progression of stone formation. The pathogenesis of calculogenesis still remains a mystery. The purpose of this paper is to assess the pathological mechanisms of stone nucleation and growth by observing the ultra microscopic morphology of the different layers of laminated stones; 130 fragments from 28 randomly selected laminated stones of more than 10-mm diameter were analysed. Wet chemical analysis of the stones was performed. Surface and cross-sectional morphology of the entire stones and the individual fragments was assessed using optical microscopy and images were recorded using ordinary camera. They were further analysed using FTIR for confirmation. By morphological analysis, whewellite, weddellite, uric acid, and phosphate were the main minerals identified. Mixtures of these minerals were also found. Concentric lamination, radial striation, frond formation, and amorphous pattern were the main cross-sectional morphologies obtained. The calculi analysed had differences in their outer and inner portions. This was more pronounced in stones containing predominantly whewellite and uric acid. Whewellite was the outer component in most mixed stones. Uric acid was more in the inner layers of mixed stones than the surface.

Topics: Calcium Oxalate; Humans; Microscopy; Spectroscopy, Fourier Transform Infrared; Uric Acid; Urinary Calculi

Stone analysis is incompletely done in many clinical centers. Identification of the stone component is essential for deciding future prophylaxis. X-ray diffraction, Fourier transform infrared spectroscopy, and scanning electron microscopy (SEM) still remains a distant dream for routine hospital work. It is in this context that optical microscopy is suggested as an alternate procedure. The objective of this article was to assess the utility of an optical microscope which gives magnification of up to 40x and gives clear picture of the surface of the stones. In order to authenticate the morphological analysis of urinary stones, SEM and elemental distribution analysis were performed. A total of 250 urinary stones of different compositions were collected from stone clinic, photographed, observed under an optical microscope, and optical photographs were taken at different angles. Twenty-five representative samples among these were gold sputtered to make them conductive and were fed into the SEM machine. Photographs of the samples were taken at different angles at magnifications up to 4,000. Elemental distribution analysis (EDAX) was done to confirm the composition. The observations of the two studies were compared. The different appearances of the stones under optical illuminated microscopy were mostly standardized appearances, namely bosselations of pure whewellite, spiculations of weddellite, bright yellow colored appearance of uric acid, and dirty white amorphous appearance of phosphates. SEM and EDAX gave clearer pictures and gave added confirmation of the stone composition. From the references thus obtained, it was possible to confirm the composition by studying the optical microscopic pictures. Higher magnification capacity of the SEM and the EDAX patterns are useful to give reference support for performing optical microscopy work. After standardization, routine analysis can be performed with optical microscopy. The advantage of the optical microscope is that, it is easy to use and samples can be analyzed in natural color.

Topics: Calcium Oxalate; Calcium Phosphates; Chemistry Techniques, Analytical; Humans; Microscopy; Microscopy, Electron, Scanning; Uric Acid; Urinary Calculi; Urolithiasis

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

The Rietveld method is one of the most innovative and most important applications in x-ray diffraction and has now, for the first time, been applied to standard-free precise quantitative crystallographic analysis of urinary stones.. The capability of the Rietveld method was demonstrated by analysis of a synthetic mixture of five typical urinary stones: whewellite, hydroxylapatite, brushite, struvite, and uric acid, with 20 weight % for each pure component.. The quantitative phase analysis (Rietveld method) yielded a mean absolute error of only 1.6% for the weight fractions of the single urinary stone components. The largest error in weight fraction, 2.3%, occurred with hydroxylapatite, caused by the typical insufficient crystallinity.. Crystallographic analysis of complex urinary stones with the aid of x-ray diffraction, in combination with a Rietveld structure refinement, is the method of first choice for qualitative and quantitative phase analysis. With this tool, significant changes in weight fractions for recurrent urinary stones can be precisely detected, with therapeutic consequences.

Topics: Calcium Oxalate; Calcium Phosphates; Crystallography, X-Ray; Durapatite; Humans; Magnesium Compounds; Phosphates; Predictive Value of Tests; Recurrence; Risk Factors; Struvite; Uric Acid; Urinary Calculi

For this study, 25 samples of urinary stones were chosen from different provinces in Iraq as representative sampling localities. These samples of urinary stones were collected to represent kidney, urate, and bladder stones. The main objectives of this study are to try to shed some light on the possibilities of tracking down the effective environmental factors that determine the mineralogical and chemical composition of these stones. The stones were examined using several techniques, the most important of which was the use of the X-ray diffraction (XRD) technique to determine the mineralogical composition of these stones. A scanning electron microscopy (SEM) test was conducted to determine the crystallographic forms and structures for the minerals forming these stones. Optical properties of these minerals were studied using a polarizing microscope. All these techniques revealed that the calcium oxalate, represented in Whewellite mineral, is the most dominant type of these stones, in addition to other minerals such as Hydroxy apatite, Struvite, and Uricite. Dittmarite was pointed out for the first time ever in some samples. This mineral has not been determined in any previous study worldwide. Considering the results of mineralogical and chemical examinations of the urinary stones in question, and the statistical information gathered from the Iraqi Health Ministry, statistical analyses were applied. The ratio of male-female cases in this study happened to be 4:1, which was higher than the ratio in the years 1988-1989 and 1993-1994, 2:1; 3:1 respectively. The highest percentage of the cases was in the 15-50 age group, which is considered as the most productive years of human lifetime. This study showed that one of the most significant factors was that the mineralogical variation of urinary stones in some Iraqi provinces was due to geographical differences, which reflect the variation in lithogenic factors and also climatological factors. Other factors may be socioeconomic, genetic, physiological, and pathological, which remain the important factors in forming urinary stones.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Apatites; Calcium Oxalate; Climate; Female; Humans; Iraq; Magnesium Compounds; Male; Microscopy, Electron, Scanning; Middle Aged; Minerals; Phosphates; Socioeconomic Factors; Struvite; Uric Acid; Urinary Calculi; X-Ray Diffraction

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

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

19 idiopathic recurrent calcium stone formers were examined on a constant diet supplemented with mineral water of high (386 mg/l) and low (10 mg/l) calcium content. The effects of calcium and oxalate loading were studied separately. Ingestion of mineral water with high calcium content lead to an increase of urinary calcium and a decrease of urinary oxalate compared to mineral water with low calcium content. On the calcium-rich mineral water, urinary saturation with Whewellite was lower and it hardly reached the critical level for calcium oxalate crystallization after oxalate loading, which was in contrast to the results on low calcium mineral water. Urinary Brushite saturation was generally low and showed no significant differences between the two mineral waters.

Topics: Adult; Calcium; Calcium Oxalate; Calcium Phosphates; Calcium, Dietary; Crystallization; Female; Fluid Therapy; Humans; Male; Middle Aged; Mineral Waters; Urinary Calculi

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

Variations of urinary pH and concentrations of calcium, phosphate, oxalate, magnesium and citrate have been produced by 4 different diets given to 19 idiopathic calcium stone formers. The state of saturation towards whewellite and brushite was directly measured in the 76 urine samples by equilibration with the corresponding salts and was compared to chemical constituents by regression analyses. The state of saturation towards calcium oxalate monohydrate was significantly governed only by the urinary oxalate concentration, and a soluble oxalate fraction not contributing to calcium oxalate chelation was demonstrated. The state of saturation towards brushite was exclusively determined by urinary calcium and pH, the latter below 5.5 showing a high influence on brushite solubility.

Topics: Adolescent; Calcium Oxalate; Calcium Phosphates; Child; Child, Preschool; Female; Humans; Hydrogen-Ion Concentration; Male; Urinary Calculi

A patient who repeatedly produced urinary calculi, had consumed about 3 g of cristobalite (SiO2) per day for many years. Investigations using scanning electron microscopy revealed minute particles containing silicon in the core of the stone as well as in urine sediment. A mechanism similar to that proposed for the effect of silicon-containing drugs against gastric ulcer, may play a role in this formation of silicon-containing urinary stones.

Topics: Apatites; Calcium Oxalate; Female; Humans; Microscopy, Electron, Scanning; Middle Aged; Silicon Dioxide; Urinary Calculi

A clay film was made of the stone powder and water drops on a slide glass and dried at 100 to 110 degrees C or at room temperature in the horizontal position for 20 calcium oxalate stones which had been received between April, 1978 and August 1980. Each clay film was scanned with an X-ray diffractometer using CuK alpha radiation, stored at room temperature in a wooden sample case and analysed again by X-ray five to seven years after the first X-ray analysis. Then the recent diffractograms of 20 powder samples were compared with the previous ones regarding the peak heights at 14.2 degrees, 14.8 degrees and 25.8 degrees (2 theta), which were considered representative of weddellite, whewellite and apatite contents and designated as Iwe, Iwh and Iap, respectively. Since there was a good correlation between Iwe/Iwe + Iwh + Iap and weddellite/weddellite + whewellite + apatite that was determined by thermogravimetry (Fig. 1), the transformation rate of weddellite to whewellite can be expressed as the change of Iwe/Iwe + Iwh + Iap. One sample Iwe/Iwe + Iwh + Iap of which decreased by 48% in seven years (Fig. 3) and another sample Iwe/Iwe + Iwh + Iap of which increased by 10% in five years (Table) were excluded from this study because the clay films of these samples might have been overheated or incompletely dried before the first X-ray analysis.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Calcium Oxalate; Humans; Urinary Calculi; X-Ray Diffraction

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

Brushite and uric acid calculi were studied by means of scanning electron microscopy with the partial dissolution method and transmission electron microscopy. Brushite calculi consist of radially oriented columnar crystals which have sheet-like substructure. The organic matrix is identified chiefly at the outside of the crystals but partly included between the substructure. The concentric matrix bands are often dislocated between the neighbouring crystals. Uric acid calculi also consist of radially oriented columnar crystals, and a fine meshwork of the organic matrix is incorporated within the crystals. The concentric matrix layers of different density are angled according to the crystal lattice. These findings indicate that the organic matrix arose from a mucinous surface coat, at least in the radially striated calculi. The crystals continued to grow in this gel-state milieu, either thrusting the matrix aside or incorporating it within the crystals.

Topics: Calcium Oxalate; Calcium Phosphates; Crystallography; Humans; Microscopy, Electron; Microscopy, Electron, Scanning; Spectrophotometry, Infrared; Uric Acid; Urinary Calculi

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

Within 12 years, 165 cases of urolithiasis were observed at the Children's University Hospital of Teheran. The incidence of urolithiasis amounts to 1 case in 300 paediatric hospitalizations. 160 calculi from 121 children were analysed by various methods: semiquantitative chemical analysis (Mercognost), x-ray diffraction, polarising microscopy on thin sections. In about 25% of the cases metabolic disorders or malformations were found responsible for urolithiasis. In 100 cases, stone formation was attributed to the upper and in 21 cases to the lower urinary tract. Calcium oxalates are the most frequent constituents, followed by ammonium acid urate. The core of the stones in the upper tract was mostly composed of calcium oxalate. Ammonium acid urate was the second important core component, but occurred especially enriched in the lower urinary tract. On the basis of these and literature data, the lack of ammonium acid urate in juvenile stones in Europe and the USA seems surprising. Thus, it must be assumed therefore, that ammonium acid urate is a key to understanding the formation of endemic calculi. The cases studied support that with increasing standard of living, the incidence of bladder stones decreases.

Topics: Adolescent; Calcium Oxalate; Child; Child, Preschool; Developing Countries; Female; Humans; India; Infant; Iran; Male; Thailand; Turkey; United Kingdom; United States; Uric Acid; Urinary Calculi

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

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

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

Three hundred urinary calculi were collected in the Durban area during the period August 1979--August 1980. Analysis by the X-ray diffraction method showed that their composition is generally similar to that found in the USA and UK. The incidence of uric acid, present in 17% of the calculi, is higher than that found overseas. There is a significantly higher incidence of calcium oxalate in calculi from Indians (83% v. 70% in Whites) while there is a significantly higher incidence of urinary apatite in Whites (35% v. 21% in Indians).

Topics: Black or African American; Black People; Calcium; Calcium Oxalate; Cystine; Female; Humans; India; Magnesium; Male; Oxalates; Phosphates; Quaternary Ammonium Compounds; South Africa; Uric Acid; Urinary Calculi; White People; X-Ray Diffraction; Xanthine; Xanthines

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

Both dried and freshly extracted samples of whewellite stones were examined by light, scanning, and transmission electron microscopy to determine the spatial distribution of the organic (matrix) and inorganic (crystal) phases. The crystalline phase was determined to occur in oriented clusters within which the crystals were stacked with their broad faces parallel. Phase contrast TEM imaging revealed gaps of the order of 100 A between all crystals, and the result of dark field TEM imaging showed that these gaps contain the amorphous phase. Thus, the indications are that the matrix is sandwiched between the crystals and may, therefore, be responsible for cohesion in these stones.

Topics: Calcium Oxalate; Crystallography; Humans; Microscopy, Electron; Microscopy, Electron, Scanning; 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

Urolithiasis is a rare complication following kidney transplantation. Experience with this complication in 6 of 426 transplantations performed from 1968 to 1979 is reviewed. The clinical symptoms are different from the disease in non-transplant patients. Three major predisposing causes for the development of calculi after kidney transplantation were found in our patients--urodynamic disorders following complications of the ureterovesical anastomosis, persistent bacteriuria and renal tubular acidosis and, less importantly, the presence of hypercalcemia and hypercalciuria as a result of secondary hyperparathyroidism. Crystal-optical and x-ray-diffraction studies contributed to the interpretation of the constituents and texture of the calculi and of the aetiological factors concerned.

Topics: Adolescent; Adult; Apatites; Calcium Oxalate; Carbonates; Female; Humans; Kidney Transplantation; Magnesium; Magnesium Compounds; Male; Phosphates; Postoperative Complications; Quaternary Ammonium Compounds; Struvite; Transplantation, Homologous; Uric Acid; Urinary Calculi

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