Stone Composition Research Articles

Performance of brushite plaster as kidney stone phantoms for laser lithotripsy.

Artificial phantoms used in photothermal near-infrared laser lithotripsy research generally fail to mimic both the chemical and the physical properties of human stones. Though high-energy, 1J pulses are capable of fracturing hard human stones into several large fragments along natural boundaries, similar behavior has not been observed in commonly used gypsum plasters like BegoStone. We developed a new brushite-based plaster formulation composed of ≈90% brushite that undergoes rapid fracture in the manner of human stones under fragmentation pulse regimes. Single-pulse (1J) ablation crater volumes for phantoms were not significantly different from those of pure brushite stones. Control over crater volumes was demonstrated by varying phosphorous acid concentration in the plaster formulation. Fragmentation of cylindrical brushite phantoms was filmed using a high-speed camera which demonstrated rapid fragmentation in < 100µs during the bubble expansion phase of a short pulse from a high-powered Ho:YAG laser (Lumenis Pulse 120H). The rapid nature of observed fracture suggests increasing laser pulse energy by increasing laser pulse duration will not improve fragmentation performance of laser lithotripters. Brushite plaster phantoms are a superior alternative to gypsum plasters for laser lithotripsy research due to their better mimicry of stone composition, controllable single-pulse crater volumes, and fragmentation behavior.

Diagnostic performance and feasibility of dual-layer detector dual-energy CT for characterization of urinary stones in patients of different sizes.

Urinary stones are frequently encountered in urology and are typically identified using non-contrast CT scans. Dual-energy CT (DECT) is a valuable imaging technique that produces material-specific images and allows for precise assessment of stone composition by estimating the effective atomic number (Zeff), a capability not achievable with the conventional single-energy CT's attenuation measurement method. To investigate the diagnostic performance and image quality of dual-layer detector DECT (dlDECT) in characterizing urinary stones in patients of different sizes. All consecutive dlDECT examinations with stone protocol and presence of urinary stones between July 2018 and November 2019 were retrospectively evaluated. Two radiologists independently reviewed 120 kVp and color-overlay Zeff images to determine stone composition (reference standard = crystallography) and image quality. The objective analysis included image noise and Zeff values measurement. A total of 739 urinary stones (median size 3.7 mm, range 1-35 mm) were identified on 177 CT examinations from 155 adults (mean age, 57 ± 15 years, 80 men, median weight 82.6 kg, range 42.6-186.9 kg). Using color-overlay Zeff images, the radiologists could subjectively interpret the composition in all stones ≥ 3 mm (n = 491). For stones with available reference standards (n = 74), dlDECT yielded a sensitivity of 80% (95%CI 44-98%) and a specificity of 98% (95%CI 92-100%) in visually discriminating uric acid from non-uric acid stones. Patients weighing > 90 kg and ≤ 90 kg had similar stone characterizability (p = 0.20), with 86% of stones characterized in the > 90 kg group and 87% in the ≤ 90 kg group. All examinations throughout various patients' weights revealed acceptable image quality. A Zeff cutoff of 7.66 accurately distinguished uric acid from non-uric acid stones (AUC = 1.00). Zeff analysis revealed AUCs of 0.78 and 0.91 for differentiating calcium-based stones from other non-uric stones and all stone types, respectively. dlDECT allowed accurate differentiation of uric acid and non-uric acid stones among patients with different body sizes with acceptable image quality. The ability to accurately differentiate uric acid stones from non-uric acid stones using color-overlay Zeff images allows for better tailored treatment strategies, helping to choose appropriate interventions and prevent potential complications related to urinary stones in patient care.

Radiological investigations in nephrolithiasis and: a narrative review

Nephrolithiasis and ureterolithiasis are increasing in incidence and prevalence worldwide, which are significant clinical challenges in management. Radiological assessments are vital in early diagnosis and effective management to decrease morbidity and healthcare costs. This narrative review explores the role of various radiological investigations in nephrolithiasis and ureterolithiasis, focusing on their clinical implications and limitations. Plain X-ray of the kidney, ureter, and bladder (X-ray KUB) is a widely available, relatively inexpensive modality with limited sensitivity, mainly for smaller stones. However, it is most beneficial when assessing follow-up patients diagnosed with renal or ureteric calculi, but it is less effective in acute ureteric colic. Intravenous Urogram/Intravenous Pyelography (IVU/IVP) is an obsolete investigation and has largely been replaced by newer modalities due to numerous drawbacks. Ultrasonography (USG) is a widely available, relatively lowcost, non-invasive radiological modality without ionising radiation, considered first-line for children and pregnant patients. However, its sensitivity and specificity are traditionally lower than computed tomography and largely depend on the operator and patient factors. Computed tomography kidney, ureter, and bladder (CT-KUB) is the gold standard for diagnosing urolithiasis. It offers high sensitivity, specificity, and the ability to calculate the exact size and stone composition, but it comes with substantial radiation exposure. However, low-dose and ultralow-dose CT (LDCTKUB) protocols reduce radiation to the patient significantly, compromising image clarity. Magnetic Resonance Urography (MRU) is a second-line investigation in obstructive uropathy, particularly in pregnancy and children. It provides vital anatomical and functional information without ionising radiation. Urology and radiology professionals should collaborate to identify individualised and optimal radiological investigations, considering the risks and benefits associated with each modality.

The first epidemiology of urolithiasis in Northern Vietnam: Urinary stone composition, age, gender, season, and clinical features study.

The aim of this study is to analyze the compositions of urinary stones and investigate their distributions in different ages, genders, seasons, and clinical features of Northern Vietnamese patients. A total of 231 patients with urinary stones from Northern Vietnam were collected and analyzed composition from 1/2021-12/2022. For all patients, age, sex, stone location, stone side, urine pH, and hospitalized date (month) were collected. Kidney stones are more frequently found in men than women with the male: female urinary stones ratio in this study being 1.96:1. The highest stone prevalence appeared between 60 and 69 years old. The most common stone composition was calcium oxalate, followed by calcium phosphate, uric acid, struvite, and cysteine. Mix stones of CaOx and CaP were more prevalent than pure stones. Males submitted more CaOx, CaP, and UA stones, whereas females were susceptible to infectious stones. Stones were more frequently found on the left side of the upper urinary tract (51.9%) than on the right side (27.3%) and lower urinary tract (7.8%). Cultural tendency leads to a smaller number of stones during the Lunar new year (February), and Ghost month (August).

Vascular Calcification in Kidney Stone Formers: The Impact of Age and Stone Composition

Vascular Calcification in Kidney Stone Formers: The Impact of Age and Stone Composition

Machine Learning Models for the Prediction of Kidney Stone Composition and Recurrence

Machine Learning Models for the Prediction of Kidney Stone Composition and Recurrence

Automatic Kidney Stone Composition Analysis Method Based on Dual-energy CT.

The composition of kidney stones is related to the hardness of the stones. Knowing the composition of the stones before surgery can help plan the laser power and operation time of percutaneous nephroscopic surgery. Moreover, patients can be treated with medications if the kidney stone is compounded by uric acid before treatment, which can relieve the patients of the pain of surgery. However, although the literature generally reports the kidney stone composition analysis method base on dual-energy CT images, the accuracy of these methods is not enough; they need manual delineation of the kidney stone location, and these methods cannot analyze mixed composition kidney stones. This study aimed to overcome the problem related to identifying kidney stone composition; we need an accurate method to analyze the composition of kidney stones. In this paper, we proposed the automatic kidney stone composition analysis algorithm based on a dual-energy CT image. The algorithm first segmented the kidney stone mask by deep learning model, then analyzed the composition of each stone by machine learning model. The experimental results indicate that the proposed algorithm can segment kidney stones accurately (AUC=0.96) and predict kidney stone composition accurately (mean Acc=0.86, mean Se=0.75, mean Sp=0.9, mean F1=0.75, mean AUC=0.83, MR (Exact match ratio)=0.6). The proposed method can predict the composition and location of kidney stones, which can guide its treatment. Experimental results show that the weighting strategy can improve kidney stone segmentation performance. In addition, the multi-label classification model can predict kidney stone composition precisely, including the mixed composition kidney stones.

In focus: perplexing increase of urinary stone disease in children, adolescent and young adult women and its economic impact.

Urinary stone disease (USD) historically has affected older men, but studies suggest recent increases in women, leading to a near identical sex incidence ratio. USD incidence has doubled every 10 years, with disproportionate increases amongst children, adolescent, and young adult (AYA) women. USD stone composition in women is frequently apatite (calcium phosphate), which forms in a higher urine pH, low urinary citrate, and an abundance of urinary uric acid, while men produce more calcium oxalate stones. The reasons for this epidemiological trend are unknown. This perspective presents the extent of USD with data from a Canadian Province and a North American institution, explanations for these findings and offers potential solutions to decrease this trend. We describe the economic impact of USD. There was a significant increase of 46% in overall surgical interventions for USD in Ontario. The incidence rose from 47.0/100,000 in 2002 to 68.7/100,000 population in 2016. In a single United States institution, the overall USD annual unique patient count rose from 10,612 to 17,706 from 2015 to 2019, and the proportion of women with USD was much higher than expected. In the 10-17-year-old patients, 50.1% were girls; with 57.5% in the 18-34 age group and 53.6% in the 35-44 age group. The roles of obesity, diet, hormones, environmental factors, infections, and antibiotics, as well as the economic impact, are discussed. We confirm the significant increase in USD among women. We offer potential explanations for this sex disparity, including microbiological and pathophysiological aspects. We also outline innovative solutions - that may require steps beyond typical preventive and treatment recommendations.

Increased risk of chronic kidney disease in uric acid stone formers with high neutrophil-to-lymphocyte ratio

Urolithiasis is associated with an increased risk of chronic kidney disease (CKD), irrespective of stone compositions. Chronic inflammation is an important factor for CKD progression. Neutrophil-to-lymphocyte ratio (NLR) has been recognized as a reliable biomarker of inflammation, yet its use in predicting renal deterioration in patients with urolithiasis remains limited. We aimed to explore whether the combination of stone composition and NLR could be useful as a predictor for CKD risk. A total of 336 stone formers with at least one stone submission for analysis were enrolled in the retrospective study. Stones were classified into uric acid and calcium groups. Renal functions were assessed at least one month after stone treatment. Uric acid stone formers had significantly lower estimated glomerular filtration rate (eGFR) compared with calcium stone formers (p < 0.001). NLR was significantly higher in uric acid stone formers (p = 0.005), and a significantly negative correlation (p < 0.001) between NLR and eGFR had been observed only in uric acid stone group. Univariate and multivariate logistic regression analyses showed that higher proportion of uric acid stone composition and higher NLR were both significantly associated with CKD risks. A nomogram integrating independent predictors was generated for CKD prediction, yielding an AUC of 0.811 (0.764–0.858). In conclusion, our study demonstrated that stone formers with higher proportion of uric acid composition and higher NLR levels were associated with higher CKD risk.

The Impact of Metabolic Factors and Lipid-Lowering Drugs on Common Bile Duct Stone Recurrence after Endoscopic Sphincterotomy with Following Cholecystectomy.

Recurrent common bile duct stone after endoscopic retrograde cholangiopancreatography is an undesirable problem, even when a following cholecystectomy is carried out. Important factors are the composition and properties of stones; the most significant etiology among these is the lipid level. While numerous studies have established the association between serum lipid levels and gallstones, no study has previously reported on recurrent common bile duct stones after endoscopic sphincterotomy with following cholecystectomy. We retrospectively collected 2016 patients underwent endoscopic sphincterotomy from 1 January 2015 to 31 December 2017 in Linkou Chang Gung Memorial Hospital. Finally, 303 patients whose serum lipid levels had been checked following a cholecystectomy after ERCP were included for analysis. We evaluated if metabolic factors including body weight, BMI, HbA1C, serum lipid profile, and lipid-lowering drugs may impact the rate of common bile duct stone recurrence. Furthermore, we tried to find if there is any factor that may impact time to recurrence. A serum HDL level ≥ 40 (p = 0.000, OR = 0.207, 95% CI = 0.114-0.376) is a protective factor, and a total cholesterol level ≥ 200 (p = 0.004, OR = 4.558, 95% CI = 1.625-12.787) is a risk factor of recurrent common bile duct stones after endoscopic sphincterotomy with cholecystectomy. Lipid-lowering drugs, specifically statins, have been shown to reduce the risk of recurrence significantly (p = 0.003, OR = 0.297, 95% CI = 0.132-0.665). No factors were found to impact the time to recurrence in this study. The serum lipid level could influence the recurrence of common bile duct stones after endoscopic sphincterotomy followed by cholecystectomy, and it appears that statins can reduce the risk of recurrence.

Pulsed Thulium:YAG laser – What is the lithotripsy ablation efficiency for stone dust from human urinary stones? Results from an in vitro PEARLS study

BackgroundThe novel pulsed thulium:yttrium–aluminum–garnet (p-Tm:YAG) laser was recently introduced. Current studies present promising p-Tm:YAG ablation efficiency, although all are based on non-human stone models or with unknown stone composition. The present study aimed to evaluate p-Tm:YAG ablation efficiency for stone dust from human urinary stones of known compositions.MethodsCalcium oxalate monohydrate (COM) and uric acid (UA) stones were subjected to lithotripsy in vitro using a p-Tm:YAG laser generator (Thulio®, Dornier MedTech GmbH, Germany). 200 J was applied at 0.1 J × 100 Hz, 0.4 J × 25 Hz or 2.0 J × 5 Hz (average 10W). Ablated stone dust mass was calculated from weight difference between pre-lithotripsy stone and post-lithotripsy fragments > 250 µm. Estimated ablated volume was calculated using prior known stone densities (COM: 2.04 mg/mm3, UA: 1.55 mg/mm3).ResultsMean ablation mass efficiency was 0.04, 0.06, 0.07 mg/J (COM) and 0.04, 0.05, 0.06 mg/J (UA) for each laser setting, respectively. This translated to 0.021, 0.029, 0.034 mm3/J (COM) and 0.026, 0.030, 0.039 mm3/J (UA). Mean energy consumption was 26, 18, 17 J/mg (COM) and 32, 23, 17 J/mg (UA). This translated to 53, 37, 34 J/mm3 (COM) and 50, 36, 26 J/mm3 (UA). There were no statistically significant differences for laser settings or stone types (all p > 0.05).ConclusionTo our knowledge, this is the first study showing ablation efficiency of the p-Tm:YAG laser for stone dust from human urinary stones of known compositions. The p-Tm:YAG seems to ablate COM and UA equally well, with no statistically significant differences between differing laser settings.

Distinguishing characteristics of pediatric patients with primary hyperoxaluria type 1 in PEDSnet

Primary hyperoxaluria type 1 (PH1) is an autosomal recessive inborn error of metabolism that causes oxalate deposition, leading to recurrent calcium oxalate kidney stones, chronic kidney disease and systemic oxalosis, which produces a broad range of serious life-threatening complications. Patients with PH1 have delayed diagnosis due to the rarity of the disease and the overlap with early-onset kidney stone disease not due to primary hyperoxaluria. The objective of this study was to determine the clinical features of individuals <21 years of age with PH1 that precede its diagnosis. We hypothesized that a parsimonious set of features could be identified that differentiate patients with PH1 from patients with non-primary hyperoxaluria-associated causes of early-onset kidney stone disease. We determined the association between clinical characteristics and PH1 diagnosis in a case-control study conducted between 2009 and 2021 in PEDSnet, a clinical research network of eight US pediatric health systems. Each patient with genetically confirmed PH1 was matched by sex and PEDSnet institution to up to 4 control patients with kidney stones without PH of any type. We obtained patient characteristics and diagnostic test results occurring before to less than 6 months after study entrance from a centralized database query and from manual chart review. Differences were examined using standardized differences and multivariable regression. The study sample included 37 patients with PH1 and 147 controls. Patients with PH1 were younger at diagnosis (median age of 3 vs 13.5 years); 75% of children with PH1 were less than 8 years-old. Patients with PH1 were more likely to have combinations of nephrocalcinosis on ultrasound or CT (43% vs 3%), lower eGFR at diagnosis (median=52mL/min/1.73m2 vs 114mL/min/1.73m2), and have normal mobility. Patients with PH1 had higher proportion of calcium oxalate monohydrate kidney stones than controls (median=100% vs 10%). There were no differences in diagnosis of failure to thrive, stone size, or echocardiography results. Children with PH1 are characterized by presentation before adolescence, nephrocalcinosis, decreased eGFR at diagnosis, and calcium oxalate monohydrate stone composition. If externally validated, these characteristics could facilitate earlier diagnosis and treatment of children with PH1.

Endoscopic Stone Composition Identification: Is Accuracy Improved by Stone Appearance During Laser Lithotripsy?

To evaluate if videos during laser lithotripsy increase accuracy and confidence of stone identification by urologists compared to still pictures. We obtained representative pictures and videos of 4 major stone types from 8 different patients during ureteroscopy with holmium laser lithotripsy. A REDCap survey was created and emailed to members of the Endourological Society. The survey included a picture followed by the corresponding video of each stone undergoing laser lithotripsy and additional clinical information. Each picture and video included multiple-choice questions about stone composition and response confidence level. Accuracy, confidence levels, and rates of rectification (change from incorrect to correct answer) or confounding (correct to incorrect) after watching videos were analyzed. One hundred eighty-seven urologists responded to the survey. The accuracy rate of stone identification with pictures was 43.8% vs 46.1% with videos (P=.27). Accuracy for individual stones was low and highly variable. Video only improved accuracy for 1 cystine stone. After viewing videos, participants were more likely to rectify vs confound their answers. Urologists were more likely to be confident with videos than pictures alone (65.4% vs 53.7%, respectively; P<.001); however, confident answers were not more likely to yield accurate predictions with videos vs still pictures. Stone identification by urologists is marginally improved with videos vs pictures alone. Overall, accuracy in stone identification is low irrespective of confidence level, picture, and lithotripsy video visualization. Urologists should be cautious in using endoscopic stone appearance to direct metabolic management.

The value of dual-energy computed tomography (DECT) in the diagnosis of urinary calculi: a systematic review and meta-analysis of retrospective studies.

Dual-energy computed tomography (DECT) imaging technology opens a new idea and method for analyzing stone composition, which can obtain several quantitative parameters reflecting tissue-related information and energy images different from traditional images. However, the application of DECT in diagnosing urinary calculi remains unknown. This study aims to evaluate the value of DECT in diagnosing urinary calculi by meta-analysis. PubMed, EMBASE, Web of Science, and the Cochrane Library were searched to articles published from the establishment of the databases to April 18, 2023. We reviewed the articles on the diagnosis of urinary calculi detected by DECT, established standards, screened the articles, and extracted data. Two researchers carried out data extraction and the Cohen's unweighted kappa was estimated for inter-investigator reliability. The quality of the literature was evaluated by the diagnostic test accuracy quality evaluation tool (QUADAS-2). The heterogeneity and threshold effects were analyzed by Meta-Disc 1.4 software, and the combined sensitivity, specificity, positive likelihood ratio, negative likelihood ratio, and diagnostic ratio were calculated. The combined receiver-operating characteristic (ROC) curve was drawn, and the value of DECT in the diagnosis of urinary calculi was evaluated by the area under the curve (AUC). The meta-analysis was registered at PROSPERO (CRD42023418204). One thousand and twenty-seven stones were detected in 1,223 samples from 10 diagnostic tests. The analyzed kappa alternated between 0.78-0.85 for the document's retrieval and detection procedure. The sensitivity of DECT in the diagnosis of urinary calculi was 0.94 (95% CI [0.92-0.96]). The positive likelihood ratio (PLR) of DECT in the diagnosis of urinary stones was 0.91 (95% CI [0.88-0.94]), and the negative likelihood ratio (NLR) was 0.08 (95% CI [0.05-0.11]). The specificity of DECT for detecting urinary calculi was 0.91 (95% CI [0.88-0.94]). The area under the curve of the summary receiver operator characteristic (SROC) was 0.9875. The sensitivity of dual-energy CT in the diagnosis of urinary calculi diameter <3 mm was 0.94 (95% CI [0.91-0.96]). The PLR of DECT in the diagnosis of urinary stones diameter <3 mm was 10.79 (95% CI [5.25 to 22.17]), and the NLR was 0.08 (95% CI [0.05-0.13]). The specificity of DECT for detecting urinary calculi <3 mm was 0.91 (95% CI [0.87-0.94]). The SROC was 0.9772. The DECT has noble application value in detecting urinary calculi.

Kidney stone twinkling power in elevated oxygen, carbon dioxide, and nitrogen environments

Clinically, ∼66% of kidney stones exhibit the Doppler ultrasound twinkling artifact. Previous studies show breathing pure oxygen at elevated pressures increases twinkling compared to ambient air. Here, we investigate how different gases influence twinkling on ex vivo and in vivo human kidney stones. 38 kidney stones were imaged with a research ultrasound system and ATL L7-4 transducer in elevated oxygen, carbon dioxide, and nitrogen environments. In vivo stones were imaged with the same ultrasound system and ATL C5-2 transducer in 25 human subjects before and after breathing pure oxygen for 15 min. IQ data were processed by calculating the average Doppler power, or twinkling, for a region of interest containing the stone. In the lab, increasing oxygen by 55%, carbon dioxide by 100%, and nitrogen by 17% increased twinkling power an average of 70 ± 28%, 137 ± 53%, and 79 ± 31%, respectively. In human subjects, breathing oxygen increased twinkling power an average of 27 ± 58%, with seven subjects showing a strong increase (&amp;gt;30%); stone composition and patient age influenced twinkling in patients breathing oxygen. These results suggest that varying ambient gases may be leveraged to increase the consistency of twinkling and improve kidney stone detection with ultrasound. [Work supported by the PSU Center for Biodevices.]

B-122 Estimated Improvement of Sigma Error Metrics Associated with Manual Secondary Result Review, and Subsequent Artificial Intelligence Driven Quality Assurance

Abstract Background Analytical and post-analytical errors are a persistent problem, which can be benchmarked using sigma metrics. Manual processes are associated with error rates of 3–4 sigma. Secondary review of manual reporting is meant to reduce/eliminate errors and is widely used, yet the true efficacy of manual secondary review is difficult to assess. Kidney stone analysis is a manually intensive process, requiring personnel to identify stone composition from spectra and to transcribe stone percent composition into an LIS system. Recently, we developed an AI program that allows for quantitative determination of kidney stone composition from spectra. This allows for a unique opportunity to estimate error rates associated with manual reporting and those following secondary review by means of subsequent AI quality assurance analysis. Methods Experienced technologists assessed stone composition and estimated the percent of each component (± 10%), based on Fourier transform infrared (FTIR) spectroscopy. These manual spectral composition assessments are secondarily reviewed by other experienced technologists for identity and percentage composition accuracy. The recently described Kidney stone AI spectral analysis (RokkStar) was implemented to assess reported stone composition identity and percent composition for agreement following secondary review in 159 334 stone reports. AI flagged discrepant reports were reviewed by personnel and reports were revised when appropriate. Secondary reviewer error detection rate was obtained by monitoring detection in a subset of 7440 kidney stones, and was that rate was extrapolated to establish secondary review error detection rate over the entire data set. The sum (total error) of estimated secondary reviewer error detection, and well as AI-mediated error detection, and all client reported errors were used to determine error rates in sigma following manual reporting, secondary review, and AI quality assurance. Results Manual entry led to an estimated 2060 errors in 159 334 stone reports, yielding an initial sigma value of 3.73. Secondary manual review resulted in an estimated 1909 (error detection rate of 92.5%) of these errors being detected over the entire report set, improving the sigma value to 4.61. Post-verification AI caught an additional 138 errors, leading to an improved post-AI sigma value of 5.27. Post-AI quality assurance, there were 13 remaining errors, 9 of which were manual reporting process deviations subsequently caught by laboratory staff, and 4 were reporting errors observed by client physicians. All 13 of these errors involved usual stone constituents or typographical errors that were not assessed by the current AI quality assurance version. Conclusion This study represents a unique large-scale estimate of efficacy of secondary result review by means of AI quality assurance review. While the presence of undetected errors cannot be completely ruled out, in this case the relative paucity of client reported errors, as well the alignment of the estimated rate of manual errors with previous reports may indicate that most errors were detected in this system. Importantly, manual secondary review improved errors rates by ∼0.9 sigma, and the use of AI further improved estimated overall sigma metric by ∼0.7, leading to a “world class” 5+ sigma level for this complex reporting process.

Кристаллообразующая активность мочи и методы ее измерения.

ntroduction. Diagnosis and determination of treatment tactics in patients with urolithiasis are based on determining the causes of lithogenesis. At the moment, the standard of examination in patients at high risk of recurrence of urolithiasis is the detection of metabolic disorders based on the results of a biochemical analysis of blood and daily urine, as well as an assessment of the chemical composition of the urinary stone. The violations determined using this approach are a manifestation of the physico-chemical processes of stone formation, the assessment of which is currently practically not performed by urologists, due to the lack of simple diagnostic methods and tools. Materials and methods. The review was conducted on the basis of data published in PubMed databases (https://www.ncbi.nlm.nih.gov/pubmed) and Scientific Electronic Library еLibrary.ru (https://elibrary.ru/), and was limited only to articles in scientific peer-reviewed journals. The search was devoted to the study of the crystal-forming activity of urine, factors affecting the lithogenic properties of urine, as well as methods for assessing the risk of stone formation in the most common metabolic types of urolithiasis. We found 189 sources no older than 10 years (published after 2012) that were relevant to the topic of the review. Conference abstracts, short messages, duplicate publications wereexcluded from them. After that, based on the relevance of the data, reliability of sources, impact factors of journals and the sequence of presentation of the material in the manuscript, 41 articles were selected directly for citation in the review. Also, when writing the review, original articles published before 2012 were used. Results. The analyzed literature sources demonstrated a large number of methods for determining the crystallization properties of urine. However, none of them, in view of the complexity, as well as the ambiguity of the results obtained, have not been widely introduced into clinical practice. In view of this, it is required to develop a simple and informative method for diagnosing the crystal-forming properties of urine, which will increase the percentage of non-reactive urolithiasis. Conclusions. The methods available to doctors for determining the crystal-forming properties of urine are extremely laborious. The development of an easy-to-use and sufficiently accurate real-time determination of the crystallization and anti-crystallization properties of urine, will significantly improve the diagnosis, treatment and metaphylaxis of urolithiasis.

The Stonehenge Altar Stone was probably not sourced from the Old Red Sandstone of the Anglo-Welsh Basin: Time to broaden our geographic and stratigraphic horizons?

Stone 80, the recumbent Altar Stone, is the largest of the Stonehenge foreign “bluestones”, mainly igneous rocks forming the inner Stonehenge circle. The Altar Stone’s anomalous lithology, a sandstone of continental origin, led to the previous suggestion of a provenance from the Old Red Sandstone (ORS) of west Wales, close to where the majority of the bluestones have been sourced (viz. the Mynydd Preseli area in west Wales) some 225 km west of Stonehenge. Building upon earlier investigations we have examined new samples from the Old Red Sandstone (ORS) within the Anglo-Welsh Basin (covering south Wales, the Welsh Borderland, the West Midlands and Somerset) using traditional optical petrography but additionally portable XRF, automated SEM-EDS and Raman Spectroscopic techniques. One of the key characteristics of the Altar Stone is its unusually high Ba content (all except one of 106 analyses have Ba > 1025 ppm), reflecting high modal baryte. Of the 58 ORS samples analysed to date from the Anglo-Welsh Basin, only four show analyses where Ba exceeds 1000 ppm, similar to the lower range of the Altar Stone composition. However, because of their contrasting mineralogies, combined with data collected from new automated SEM-EDS and Raman Spectroscopic analyses these four samples must be discounted as being from the source of the Altar Stone. It now seems ever more likely that the Altar Stone was not derived from the ORS of the Anglo-Welsh Basin, and therefore it is time to broaden our horizons, both geographically and stratigraphically into northern Britain and also to consider continental sandstones of a younger age. There is no doubt that considering the Altar Stone as a ‘bluestone’ has influenced thinking regarding the long-held view to a source in Wales. We therefore propose that the Altar Stone should be ‘de-classified’ as a bluestone, breaking a link to the essentially Mynydd Preseli-derived bluestones.

Spectral characterization of renal calculi collected from population in downtown Madrid (Spain)

This paper reports on a comprehensive approach to characterize a set of kidney stones through various analytical techniques including ESEM-EDS, XRD, Raman, and CL spectroscopy, linked to an assessment of the patient's lifestyle and dietary habits. The use of these techniques can provide valuable insights into the underlying causes of stone formation and guide strategies for prevention and treatment. ESEM-EDS and XRD are commonly used techniques for kidney stone characterization due to their complementary nature, enabling the identification of a wide range of renal calculi. However, these techniques may not be sensitive enough to determine the detailed composition of the samples. In such cases, Raman and CL techniques can be used to provide more precise information about the chemical and structural composition of the stones. Raman spectroscopy, for example, can identify molecular phases observed under an optical microscope characterizing chemical compositions through vibrational modes associated with specific bonds. The CL spectral emission within the 250–850 nm range can also yield valuable information about the mineral phases, including the identification of structural crystallinity, hydrated molecules, Ca-OH bonds, and oxygen defects. By correlating spectral analyses with patient habits, this study identifies potential exogenous factors contributing to stone formation, including excess protein consumption, urinary bacterial infections, and oxalate-rich diets. This comprehensive approach provides a more complete understanding of the composition of kidney stones helping to personalized prevention and treatment strategies.

Correlation of serum biochemical characteristics and ABCG8 genetic variant (rs 11887534) with gall stone compositions and risk of gallstone disease in a group of Egyptian patients.

The overexpression of the cholesterol transporter: ATP-binding cassette transporter (ABCG8) due to the effect of ABCG8 genetic variant (rs11887534) leads to the precipitation of cholesterol crystals and gallstone disease (GSD). To evaluate the chemical composition of gallstones and the role of ABCG8 (rs11887534) in the susceptibility to GSD. We enrolled 77 patients with GSD treated with standard laparoscopic or open cholecystectomy and 75 age and sex-matched healthy controls. Chemical analysis of the extracted gallstones was performed. Analysis of the rs11887534 was performed by real-time PCR TaqMan technique for both cases and controls. Pure cholesterol stones were the main type of stones in GSD patients. The CC genotype carriers of rs11887534 were more prone to gallstone formation than other genotypes. The CC genotype carriers were 100 folds at increased risk to develop pure cholesterol stones. The most prevalent type of gallbladder stones is pure cholesterol stone. ABCG8 (rs11887534) could be associated with increased risk for cholesterol gallstones formation, this risk was more pronounced in female patients.