The elementome of calcium-based urinary stones and its role in urolithiasis

The key role of major and trace elements in the formation of five common urinary stones

BACKGROUND

Urolithiasis has emerged as a global affliction, recognized as one of the most excruciating medical issues. The elemental composition of stones provides crucial information, aiding in understanding the causes, mechanisms, and individual variations in stone formation. By understanding the interactions between elements in various types of stones and exploring the key role of elements in stone formation, insights are provided for the prevention and treatment of urinary stone disease.

METHODS

This study collected urinary stone samples from 80 patients in Beijing. The chemical compositions of urinary stones were identified using an infrared spectrometer. The concentrations of major and trace elements in the urinary stones were determined using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma Mass Spectrometry (ICP-MS), respectively. The data were processed using correlation analysis and Principal Component Analysis (PCA) methods.

RESULTS

Urinary stones are categorized into five types: the calcium oxalate (CO) stone, carbonate apatite (CA) stone, uric acid (UA) stone, mixed CO and CA stone, and mixed CO and UA stone. Ca is the predominant element, with an average content ranging from 2.64 to 27.68% across the five stone groups. Based on geochemical analysis, the high-content elements follow this order: Ca > Mg > Na > K > Zn > Sr. Correlation analysis and PCA suggested significant variations in the interactions between elements for different types of urinary stones. Trace elements with charges and ionic structures similar to Ca may substitute for Ca during the process of stone formation, such as Sr and Pb affecting the Ca in most stone types except mixed stone types. Moreover, the Mg, Zn and Ba can substitute for Ca in the mixed stone types, showing element behavior dependents on the stone types.

CONCLUSION

This study primarily reveals distinct elemental features associated with five types of urinary stones. Additionally, the analysis of these elements indicates that substitutions of trace elements with charges and ion structures similar to Ca (such as Sr and Pb) impact most stone types. This suggests a dependence of stone composition on elemental behavior. The findings of this study will enhance our ability to address the challenges posed by urinary stones to global health and improve the precision of interventions for individuals with different stone compositions.

Nickel as a modifier of calcium oxalate: an in situ liquid cell TEM investigation of nucleation and growth

Despite extensive research on the nucleation and growth of calcium oxalate (CaOx) crystals, there are still several challenges and unknowns that remain. In particular, the role of trace metal elements in the promotion or inhibition of CaOx crystals is not well understood. In the present study, in situ graphene liquid cell transmission electron microscopy (in situ GLC TEM) was used to observe real-time, nanoscale transformations of CaOx crystals in the presence of nickel ions (Ni2+). The results showed that Ni2+ form Ni-water complexes, acting as a shape-directing species, generating a unique morphology and altering growth kinetics. Transient adsorption of Ni-water complexes resulted in a metastable phase formation of calcium oxalate trihydrate. Atomistic molecular dynamics simulations confirmed that Ni2+ acts as a weak inhibitor which slows down the CaOx crystallization, elucidating that Ni2+ impacts small-sized CaOx clusters by bringing more water into the clusters. This work highlighted the intricacies behind the effect of Ni2+ on CaOx biomineralization that were made possible to discern using in situ GLC TEM.

Assessment of the incidence and risk factors of postoperative urosepsis in patients undergoing ureteroscopic lithotripsy

Introduction

Ureteroscopic lithotripsy (URSL) is an approved, minimally invasive, low-risk procedure for urolithiasis treatment. However, some patients may develop urinary tract infection (UTI) post-procedure, eventually leading to urosepsis. Determining the predictors of infection after URSL would help identify patients at a high risk of urosepsis, thereby enabling the early implementation of effective treatment. Therefore, we aimed to establish the incidence and predictors of urosepsis after URSL.

Material and methods

We assessed 231 patients who underwent URSL using a holmium laser. The incidence of urosepsis during the 30-day post-treatment period was analysed, and potential predictors of urosepsis, including patient characteristics and individual clinical factors, were examined.

Results

Statistical analysis revealed that 16.88% of patients had a confirmed positive urine culture before the procedure. Post-procedure urosepsis occurred in 4.76% of patients. Univariable analysis revealed that 3 factors were significantly associated with the risk of postoperative urosepsis: double-J stent insertion before URSL, pre-operative positive urine culture, and MDR pathogen found preoperatively. In multivariable analysis, only positive urine culture remained significantly associated with the risk of urosepsis after URSL.

Conclusions

Patients with positive urine culture before URSL are at significantly higher risk of urosepsis in the postoperative period. Hence, urine culture should be routinely performed before planned endoscopic urolithiasis treatment.

A Simple Laser-Induced Breakdown Spectroscopy Method for Quantification and Classification of Edible Sea Salts Assisted by Surface-Hydrophilicity-Enhanced Silicon Wafer Substrates

Salt, one of the most commonly consumed food additives worldwide, is produced in many countries. The chemical composition of edible salts is essential information for quality assessment and origin distinction. In this work, a simple laser-induced breakdown spectroscopy instrument was assembled with a diode-pumped solid-state laser and a miniature spectrometer. Its performances in analyzing Mg and Ca in six popular edible sea salts consumed in South Korea and classification of the products were investigated. Each salt was dissolved in water and a tiny amount of the solution was dropped and dried on the hydrophilicity-enhanced silicon wafer substrate, providing homogeneous distribution of salt crystals. Strong Mg II and Ca II emissions were chosen for both quantification and classification. Calibration curves could be constructed with limits-of-detection of 87 mg/kg for Mg and 45 mg/kg for Ca. Also, the Mg II and Ca II emission peak intensities were used in a k-nearest neighbors model providing 98.6% classification accuracy. In both quantification and classification, intensity normalization using a Na I emission line as a reference signal was effective. A concept of interclass distance was introduced, and the increase in the classification accuracy due to the intensity normalization was rationalized based on it. Our methodology will be useful for analyzing major mineral nutrients in various food materials in liquid phase or soluble in water, including salts.

A simple assessment of the effect of strontium on the urinary excretion of calcium in Sprague Dawley rats

This study was aimed at investigating the impact of varying concentrations of strontium (Sr) on calcium (Ca) excretion via the urine and determine its impact on kidney stone formation. Twenty adult male Sprague Dawley rats weighing between 200 and 300 g were selected. The rats were randomly divided into four groups of five. One group was used as a control group while the other three groups were experimental. The diet of the rats was modulated over a 12 week period to investigate the impact of Sr on the urinary excretion of Ca. Urinary samples were collected every 2 weeks from the rats. The rats were fed water ad libitum. After the study the rats were euthanised and their kidneys harvested. Urine and kidney samples from the rats were analysed using Total Reflection X-Ray Fluorescence (TXRF). In the urine excretion of Ca increased with increased intake of Sr in the diet. Sr excretion via the urine also increased with increased dietary intake. There was a correlation of 0.835 at the significance level of 0.01 between Ca and Sr in the urine. However, for the kidneys, the varying concentration of Sr did not impact the retention of Ca in the kidneys. There was increased retention of Sr in the kidneys with increased dietary intake. In this study an increase of Sr in the diet resulted in an increase in urinary excretion of Ca.

Detection of Cadmium and Lead in Kidney Stones. Associations with Patient Demographics, Stone Composition, and Smoking

BACKGROUND

Kidney stones are a highly prevalent disease worldwide. Additionally, both environmental and occupational exposure to Pb and Cd continue to be prevalent globally and can result in renal toxicity. The objective of this study was to examine the potential presence of Pb and Cd in kidney stones, and to assess for correlation with demographic factors including smoking, gender, age, and kidney stone matrix composition.

METHODS

Patient kidney stones (n = 96) were analyzed using Fourier transform infrared spectroscopy to identify the stone constituents. Cd and Pb concentrations (µg/g) were determined by inductively coupled plasma mass spectrometry. Cd and Pb concentrations were correlated using bivariable and multivariable statistical analysis with demographic factors (age, gender, smoking status), and kidney stone composition.

RESULTS

Kidney stone Cd (median 0.092 µg/g, range 0.014 to 2.46) and Pb concentrations (median 0.95 µg/g, range 0.060 to 15.4) were moderately correlated (r = 0.56, P < 0.0001). Cd concentrations were positively associated with patient history of smoking, patient age, and calcium oxalate monohydrate levels while negatively associated with struvite and uric acid/uric acid dihydrate. Pb concentrations were positively associated with females and apatite levels while negatively associated with uric acid/uric acid dihydrate. After holding constant other stone type composition levels, smoking status, and age, both Pb and Cd were positively associated with apatite and negatively associated with uric acid/uric acid dihydrate, struvite, and calcium carbonate.

CONCLUSIONS

Cd and Pb kidney stone concentrations are associated with specific kidney stone types. Cd and Pb kidney stone concentrations are both associated with smoking.

Did the COVID-19 Pandemic Restrict Access to Emergency Urological Services: Assessment of Reorganisation Effectiveness for Hospital Treatment

Urolithiasis derived renal colic is a common urological condition. If treated properly, the disease resolves without complications; if not treated, it causes infection and renal failure. The COVID-19 restrictions impacted hospitalised treatment of diseases. We analysed the impact of COVID-19 on renal colic treatment at a hospital in Poland. Clinical and demographic data of patients treated during the COVID-19 era were compared with those treated before this pandemic. During the COVID-19 restrictions, renal colic patient hospital admissions fell significantly. However, more patients presented with chronic renal colic symptoms and urinary tract infections. Nevertheless, the degree of hydronephrosis and the number and location of stones did not differ between the two groups. No marked changes were observed in the chosen treatment options. The observed decrease in emergency admissions of patients with acute renal colic with a simultaneous increase in the rate of infectious stones might indicate that some patients requiring urgent medical help did not report to the emergency department or came later than they would before the pandemic, reporting more serious symptoms. One plausible explanation for this may be that the reorganisation of the healthcare system restricted access to urological care. Moreover, some patients may have delayed their visit to the hospital due to the fear of contracting the SARS-CoV-2 coronavirus.

Prevalence and Risk Factors of Urolithiasis Among the Population of Hail, Saudi Arabia

Background Urolithiasis is the formation of calculi in the urinary system. It is a public health concern worldwide that can lead to serious long-term consequences. Age, gender, dietary habits, and physical activity levels are all factors that increase the risk of urolithiasis formation. Furthermore, the presence of comorbid medical conditions such as diabetes and hypertension are other major risk factors. Among the most prominent determinants that raise the likelihood of acquiring urolithiasis is exposure to high temperatures, especially in middle-aged men. Consequently, Saudi residents are two and a half times more prone than the global average to develop urolithiasis, especially those in the Kingdom's hottest regions. Methodology This cross-sectional study assessed the self-reported prevalence and non-nutritional risk factors of urolithiasis among the population of Hail, Saudi Arabia, through an electronic questionnaire. The questionnaire contained 16 questions divided into three categories. Participants' permission was obtained before completing the questionnaire. The Statistical Package for Social Sciences (SPSS) version 22 (IBM Corp., Armonk, NY, USA) was used to analyze the data. Results Of the 1150 participants with a mean age of 26.3 ± 12.8 years old, nearly half were males (50.9%). Urolithiasis was detected among 158 (13.7%) participants. The following factors showed significant relation with having urolithiasis: increased age, male gender, a low level of education, diabetes, hypertension, and hyperthyroidism. A family history of renal stones was also associated with double the risk of having urolithiasis. Conclusion The results showed a high prevalence of urolithiasis in the Hail region, with many risk factors associated with it. It is important to support and promote awareness campaigns that address the critical risk factors of urolithiasis. Further studies should be conducted to arrive at a better understanding of the association between non-nutritional risk factors and developing urolithiasis.

Prediction of the composition of urinary stones using deep learning

PURPOSE

This study aimed to predict the composition of urolithiasis using deep learning from urinary stone images.

MATERIALS AND METHODS

We classified 1,332 stones into 31 classes according to the stone composition. The top 4 classes with a frequency of 110 or more (class 1: calcium oxalate monohydrate [COM] 100%, class 2: COM 80%+struvite 20%, class 3: COM 60%+calcium oxalate dihydrate [COD] 40%, class 4: uric acid 100%) were selected. With the 965 stone images of the top 4 classes, we used the seven convolutional neural networks (CNN) to classify urinary stones and compared their classification performances.

RESULTS

Among the seven models, Xception_Ir0.001 showed the highest accuracy, precision, and recall and was selected as the CNN model to predict the stone composition. The sensitivity and specificity for the 4 classes by Xception_Ir0.001 were as follows: class 1 (94.24%, 91.73%), class 2 (85.42%, 96.14%), class 3 (86.86%, 99.59%), and class 4 (94.96%, 98.82%). The sensitivity and specificity of the individual components of the stones were as follows. COM (98.82%, 94.96%), COD (86.86%, 99.64%), struvite (85.42%, 95.59%), and uric acid (94.96%, 98.82%). The area under the curves for class 1, 2, 3, and 4 were 0.98, 0.97, 1.00, and 1.00, respectively.

CONCLUSIONS

This study showed the feasibility of deep learning for the diagnostic ability to assess urinary stone composition from images. It can be an alternative tool for conventional stone analysis and provide decision support to urologists, improving the effectiveness of diagnosis and treatment.

Quantitative phase analysis and microstructural characterization of urinary tract calculi with X-ray diffraction Rietveld analysis on a Caribbean island

In the twin-island state of Trinidad and Tobago, urinary stone analysis is not routinely performed. This study investigates, via powder X-ray diffraction, 52 urinary tract calculi collected from hospitals in Trinidad. Of these, 46 stones were analysed with Rietveld refinement for quantitative analysis and materials characterization. Refined unit-cell, microstructural and weight fraction parameters were obtained, with the last being used for stone classification. The results revealed seven distinct mineralogical phases of varying frequency: calcium oxalate monohydrate (COM, 58%), calcium oxalate dihydrate (COD, 23%), carbonated apatite (APA, 48%), brushite (BRU, 6%), struvite (STR, 42%), uric acid (UA, 23%) and ammonium acid urate (AAU, 19%). The average refined crystallite sizes were 1352 ± 90 Å (COM), 1921 ± 285 Å (COD), 83 ± 5 Å (APA), 1172 ± 9 Å (BRU), 1843 ± 138 Å (STR), 981 ± 87 Å (UA) and 292 ± 83 Å (AAU). Subsequently, 36.5% of stones were categorized as phosphates, 34.6% as oxalates, 13.5% as uric acid/urates and 15.4% as mixed compositions. The study findings highlight the importance of stone analysis as a necessary step towards disease management of local patients, and endorse the application of Rietveld refinement as a natural extension to diffraction-based kidney stone investigations.

Spectroscopic Characterization of Urinary Stones Richening with Calcium Oxalate

Intact and non-intact urinary stones richening with calcium oxalate were collected and characterized. The elemental analysis, phase quantifications, and function groups were determined by different spectroscopic techniques, namely: energy-dispersive X-ray fluorescence (EDXRF), the synchrotron radiation X-ray diffraction (SR-XRD), and attenuated total reflection Fourier transform infrared (ATR-FTIR). The quantitative analysis of twenty elements was demonstrated in the most of the urinary stones and these elements are: Ca, Na, P, S, Mg, Cl, Zn, K, Ti, Sr, Ni, Co, Fe, Cu, Cd, Br, Pb, Se, I, and Mn. Using the Rietveld method, the diffraction phase quantification was illustrated. The main found phases are calcium oxalate (monohydrate and dihydrate) and hydroxyapatite phase. The FTIR outcomes reveal that the functional groups of O-H, N-H, C=O, and C-O indicate to the calcium oxalate whereas the P-O and O-P-O, and PO₄^3- groups indicate to the calcium phosphates in the hydroxyapatite. A considerable correlations between the oxalate urinary stones and the group of elements were found. These elements are Zn, Sr, Ni, and Fe. These correlations could lead to new therapeutic approaches. Furthermore, the elements of sodium and chlorine have no vital role in the formation of calcium oxalate urinary stones.

Heavy metals in urinary stones in the Democratic Republic of Congo

Background

The Democratic Republic of Congo has been a country of intensive mining activities for centuries, but the data on the presence of heavy metals in stones are lacking. This study aimed to identify different heavy metals in urinary tract stones and to investigate their association with the main components of urinary stones.

Methods

Thirty-six stones from urolithiasis patients (n = 36) followed in 10 hospitals in the Democratic Republic of Congo between January 2016 and September 2019 were analyzed by Fourier transform infrared spectrophotometry. Further analysis using X-ray fluorescence was conducted at the Laboratory of Solids Physics.

Results

Eight heavy metals were detected in all the stones analyzed. The average (SD) number of heavy metals detected by stone was 5 (1.2). Iron and strontium were detected in all the stones analyzed. Other heavy metals detected included zinc, copper, bromine, rubidium, lead and nickel. Rubidium had the highest concentration in the stones regardless of the sampling site. There was no statistically significant association between the content of heavy metals at the center level and at the crown level of the stones. Rubidium had more affinity with phosphates and purines (p ˂ 0.001). Iron and strontium exhibited a high affinity with weddellite than with whewellite.

Conclusion

Iron and Strontium were present in all stones analyzed. The presence of heavy metals in stones analyzed might suggest environmental pollution rather than crystalline induction factors.

Omics in urology: An overview on concepts, current status and future perspectives

Recent technological advances in molecular biology have led to great progress in the knowledge of structure and function of cells and their main constituents. In this setting, 'omics' is standing out in order to significantly improve the understanding of etiopathogenetic mechanisms of disease and contribute to the development of new biochemical diagnostics and therapeutic tools. 'Omics' indicates the scientific branches investigating every aspect of cell's biology, including structures, functions and dynamics pathways. The main 'omics' are genomics, epigenomics, proteomics, transcriptomics, metabolomics and radiomics. Their diffusion, success and proliferation, addressed to many research fields, has led to many important acquisitions, even in Urology. Aim of this narrative review is to define the state of art of 'omics' application in Urology, describing the most recent and relevant findings, in both oncological and non-oncological diseases, focusing the attention on urinary tract infectious, interstitial cystitis, urolithiasis, prostate cancer, bladder cancer and renal cell carcinoma. In Urology the majority of 'omics' applications regard the pathogenesis and diagnosis of the investigated diseases. In future, its role should be implemented in order to develop specific predictors and tailored treatments.

Study of risk factor of urinary calculi according to the association between stone composition with urine component

Urolithiasis is a common urinary disease with high recurrence. The risk factor for the recurrence of calculi is not very clear. The object of the present study was to evaluate the association between calculi composition and urine component and analyse the risk factor for the recurrence of urolithiasis. In this study, a total of 223 patients with calculi and healthy control were enrolled, and the components of the calculi and urina sanguinis collected before surgery were analysed. Of the 223 patients, 157 were males and 66 were females. According to the stone composition, the case group was subdivided into three groups. 129 patients had single calcium oxalate stones, 72 had calcium oxalate stones mixed with other stones and 22 had other type of stones excluding calcium oxalate stones. Urine biochemicals were analysed and the associations were found between the chemicals in each group. Multivariate logistic analysis demonstrated that reduced urinary magnesium and uric oxalic acid were independent risk factors when comparing all cases with normal controls. Only decreased urinary magnesium was found to be a risk factor comparing the single calcium oxalate group with normal control group. Low level of urinary magnesium and uric oxalic acid were found to be risk factors comparing the mixed calcium oxalate group with normal control group. No risk factor was found comparing the other stone group with normal control group. In conclusion, there were clear relationships between stone components and urine chemicals. Urine chemicals might be risk factors to predicate the occurrence of urolithiasis.

Comparative analysis of Rhipicephalus tick salivary gland and cement elementome

Rhipicephalus spp. (Acari: Ixodidae) ticks are obligate hematophagous arthropods, which constitute a model for the study of vector-host interactions. The chemical composition or elementome of salivary glands (SG) and cement provides information relevant for the study of protein-based complex multifunctional tissues with a key role in tick biology. In this study, we characterized the elementome of cement cones in Rhipicephalus sanguineus collected from naturally infested dogs and in SG and cement of R. bursa collected from experimentally infested rabbits at different feeding stages. The elementome was characterized using scanning electron microscopy (SEM) combined with energy dispersive X-ray spectroscopy (EDS). The results showed the identification of up to 14 chemical elements in the cement, and suggested tick/host-driven differences in the cement elementome between tick species and between SG and cement within the same species. By still unknown mechanisms, ticks may regulate cement elementome during feeding to affect various biological processes. Although these analyses are preliminary, the results suggested that N is a key component of the cement elementome with a likely origin in SG/salivary proteins (i.e., Glycine (C2H5NO2)-rich superfamily member proteins; GRPs) and other tick/host-derived components (i.e. NAPDH). Future research should be focused on tick elementome and its functional implications to better understand cement structure and function.

Medical evaluation and pharmacotherapeutical strategies in management of urolithiasis

Treatment of urolithiasis depends on several important factors which include stone location, size, composition, and patient symptoms. Although significant advancements have been made in the surgical management of urolithiasis in the last decade, pharmacotherapy which can prevent the formation of new stones and decrease the recurrence of urolithiasis has not experienced the same level of success. Currently, urolithiasis is regarded as a complicated syndrome that is determined by numerous factors, and any treatment plan for urolithiasis should be individualized while considering any potential damage arising from stone-forming factors. This review introduces the most popular methods currently used to evaluate urolithiasis and the pharmacotherapy of urolithiasis based on patient-specific factors.

Identification of Novel Human Serum Albumin (SA) Inhibitors from Scoparia Dulsis for Urolithiasis

Background::

Urolithiasis is the process of forming stones in the kidney, bladder, and/or urinary tract. It has been reported that kidney stones are the third most common disorder among urinary diseases. At present, surgical procedures and Extracorporeal Shock Wave Lithotripsy (ESWL) are commonly employed for the treatment of Urolithiasis. The major drawback of these procedures is the recurrence of stones.

Methods:

This study aimed to identify potential natural inhibitors against human Serum Albumin (SA) from the plant Scoparia Dulsis for Urolithiasis. As protein-ligand interactions play a key role in structure- based drug design, this study screened 26 compounds from Scoparia Dulsis and investigated their binding affinity against SA by using molecular docking. The three dimensional (3D) structure of SA was retrieved from Protein Data Bank (PDB) and docked with PubChem structures of 26 compounds using PyRX docking tool through Autodock Vina. Moreover, a 3D similarity search on the PubChem database was performed to find the analogs of best scored compound and docking studies were performed. Drug-likeness studies were made using Swiss ADME and Lipinski’s rule of five was performed for the compounds to evaluate their anti-urolithiatic activity.

Results:

The results showed that citrusin c (Eugenyl beta-D-glucopyranoside) exhibited best binding energy of -8.1 kcal/mol with SA followed by aphidicolin, apigenin, luteolin and scutellarein. Two compounds (PubChem CID 46186820, PubChem CID 21579141) analogous to citrusin c were selected based on the lowest binding energy.

Conclusion:

This study, therefore, reveals that these compounds could be promising candidates for further evaluation for Urolithiasis prevention or management.

Analysis of stones formed in the human gall bladder and kidney using advanced spectroscopic techniques

Stone diseases (gallstones and kidney stones) are extremely painful and often cause death. The prime aim of biomedical research in this area has been determination of factors resulting in stone formation inside the gallbladder and urinary tract. Many theories have been put forward to explain the mechanism of stone formation and their growth; however, their complete cycle of pathogenesis is still under debate. Several factors are responsible for stone formation; however, much emphasis is placed on the determination of elemental and molecular composition of the stones. In the present review article, we describe different kinds of spectroscopic techniques such as Fourier transform infrared spectroscopy (FTIR), X-ray fluorescence (XRF) spectroscopy, time-of-flight secondary ion mass spectrometry (TOF-SIMS), and laser-induced breakdown spectroscopy (LIBS) and highlight their use in the analysis of stone diseases. We have summarized work done on gallstones and kidney stones using these advanced techniques particularly over the last 10 years. We have also briefly elaborated the basics of stone formations inside the human body and their complications for a better understanding of the subject.

Urolithiasis: Prevalence, risk factors, and public awareness regarding dietary and lifestyle habits in Jeddah, Saudi Arabia in 2017

Introduction:

Urolithiasis is a public health concern, yet there are limited studies in our community. This study aimed to provide a current estimate of the prevalence of urolithiasis and to evaluate the public's awareness about dietary and lifestyle habits that impact on urolithiasis among the Jeddah population in 2017.

Methods:

This is an observational cross-sectional study design where a self-administered questionnaire was distributed in two major malls in Jeddah. The total number of participants was 2173, who were Saudis and non-Saudis aged 18 years and above. The questionnaire includes five sections: demographics, general information related to urolithiasis, dietary information related to urolithiasis, lifestyle habits, and medical conditions.

Results:

The overall prevalence of urolithiasis was 11.2%, 48.8% of which had a family history with a first-degree relative. The odds of urolithiasis among males was 1.8 times higher than in females (odds ratio [OR] =1.8, 95% confidence interval [CI], 1.4–2.4). The median age of stone disease was 33 years (25%–75%: 26–42 years). Diabetic individuals were 3.2 times more likely to have urolithiasis when compared to nondiabetic individuals (OR = 3.2, 95% CI, 2.1–4.9). Low level of awareness was observed in this cohort group with a mean score of 37.7%; 64.1% of the population were in the low awareness level, 35.3% were in the medium level, and only 0.6% participants were in the high level of awareness.

Conclusion:

This study highlights the lack of public awareness about urolithiasis and knowledge about its causation despite the high prevalence. There is a clear need to inform and educate the public on matters relating to the known risk factors associated with urolithiasis.

Feasibility of Quantitative Analysis of Magnesium and Calcium in Edible Salts Using a Simple Laser-Induced Breakdown Spectroscopy Device

Feasibility of a simple laser-induced breakdown spectroscopy (LIBS) device has been investigated for the analysis of Mg and Ca in edible salts. The LIBS spectrometer was assembled with a compact low-power diode-pumped solid-state laser (DPSSL) and a non-gated low-resolution handheld spectrometer. A simple sampling process was employed for on-site application. A piece of filter paper was dipped in the aqueous solution of a sample salt and dried for analysis using LIBS. Maintaining the sample surface height at the optimum position was critical to generate plasmas persistently due to the low pulse energy of the DPSSL. The varying height of the filter paper surface was monitored and compensated, while the sample stage was translated to collect spectra from different positions. The variation of line intensities of Mg and Ca could be attributed to the inhomogeneous distribution of dry residues. To correct this, the peak that consists of the Na(I) and C(II) lines at 568 nm was employed as a reference signal for intensity normalization of the analyte Mg(II) and Ca(II) lines. For edible salt products, the normalized Mg(II) and Ca(II) line intensities could be well correlated with the concentrations of Mg and Ca determined using inductively coupled plasma optical emission spectroscopy. Our results indicate that a simple LIBS device in combination with the simple sampling method is promising as an on-site salt quality assessment methodology.

A Short Review on the Relationships Between Nephrolithiasis and Myocardial Infarction

The interaction between organs is a crucial part of modern medicine. As a very prerequisite to manage a disease, practitioners should have a full awareness of the related organs. Kidney and heart are two vital organs that are closely interconnected in various fields. These two organs have a lot of common risk factors for making a person unhealthy; therefore, if you prevent the disease in one of them, the other's morbidity might be alleviated as well. Among them, nephrolithiasis and myocardial infarction (MI) have more risk factors in common, and both could be fatal. Also, these two diseases are important regarding the prevalence, incidence, and burden of disease. Some studies confirm the relationship between MI and nephrolithiasis; however, further researches are needed to discover the exact direction of their relationship. The present review aims to explain the mechanism of MI and nephrolithiasis; clarify the relationship between these two disease based on physiological, pathological, and clinical studies; and propose some solutions for the prevention and treatment of such diseases.

Composition and spatial distribution of elements and isotopes of a giant human bladder stone and environmental implications

The composition and spatial distribution of minerals, trace elements, as well as carbon and nitrogen isotopes from the outer crust to inner nucleus of a 20-year old giant human bladder stone comprising thirteen layers were intensively investigated. Calcium oxalate monohydrate (COM) was found to concentrate in the inner and middle layers, struvite was concentrated in middle and outer layers, and fluorapatite occurred in almost all layers. The spatial distribution of minerals has the potential to provide preliminary knowledge regarding the long-term urine composition, or even the physiological condition of the patient. The stable carbon isotope ratio (δ¹³C) and stable nitrogen isotope ratio (δ¹⁵N) were measured in each layer and significant correlation was found between δ¹³C with calcium oxalate monohydrate content and between δ¹⁵N and struvite content. Nearly constant values of -23.2‰ and 7.1‰ for δ¹³C and δ¹⁵N, respectively, were found in the organic components of the stone. Both isotope ratios indicate a long-term fixed diet consisting mainly of C3 plants, such as rice and wheat, for the 20-year time period of the stone formation. In addition, eighteen elements (Ca, P, Mg, K, Na, Al, Fe, Zn, Pb, Cu, Sr, Ba, Ti, V, Cr, Ni, Mn and Co) were measured in all the layers. The trace elements Al, Fe, Cu, Zn, Pb, Sr, Ba and Ti showed a similar spatial distribution pattern from the outer crust to the inner core. Although there were complex correlations between elements and minerals, Factor Analysis suggests that the occurrence of these elements in stones may be mainly the result of environmental exposure to metals during the formation of the stone, indicating that urinary stones may serve as potential long-term biomonitors. In particular, Ni and Cr showed a distinct distribution pattern in the stone, which may relate to human metabolic activities.

Architecture-Guided Fluid Flow Directs Renal Biomineralization

Nephrocalcinosis often begins on a calcium phosphate deposit, at the tip of the medullo-papillary complex (MPC) known as Randall’s plaque (RP). Contextualizing proximally observed biominerals within the MPC has led us to postulate a mechanobiological switch that can trigger interstitial biomineralization at the MPC tip, remote from the intratubular biominerals. Micro X-ray computed tomography scans of human MPCs correlated with transmission and scanning electron micrographs, and X-ray energy dispersive spectrometry demonstrated novel findings about anatomically-specific biominerals. An abundance of proximal intratubular biominerals were associated with emergence of distal interstitial RP. The fundamental architecture of the MPC and mineral densities at the proximal and distal locations of the MPC differed markedly. A predominance of plate-like minerals or radially oriented plate-like crystallites within spheroidal minerals in the proximal intratubular locations, and core-shell type crystallites within spheroidal minerals in distal interstitial locations were observed. Based on the MPC anatomic location of structure-specific biominerals, a biological switch within the mineral-free zone occurring between the proximal and distal locations is postulated. The “on” and “off” switch is dependent on changes in the pressure differential resulting from changes in tubule diameters; the “Venturi effect” changes the “circumferential strain” and culminates in interstitial crystal deposits in the distal tubule wall in response to proximal tubular obstruction. These distal interstitial mineralizations can emerge into the collecting system of the kidney linking nephrocalcinosis with nephrolithiasis.

Nanocomposite Porous Microcarriers Based on Strontium-Substituted HA- g-Poly(γ-benzyl-l-glutamate) for Bone Tissue Engineering

Porous microcarriers have aroused increasing attention recently, which can create a protected environment for sufficient cell seeding density, facilitate oxygen and nutrient transfer, and well support the cell attachment and growth. In this study, porous microcarriers fabricated from the strontium-substituted hydroxyapatite- graft-poly(γ-benzyl-l-glutamate) (Sr10-HA- g-PBLG) hybrid nanocomposite were developed. The surface grating of PBLG, the micromorphology and element distribution, mechanical strength, in vitro degradation, and Sr²⁺ ion release of the obtained Sr10-HA- g-PBLG porous microcarriers were investigated, respectively. The grafting ratio and the molecular weight of the grafted PBLG of Sr10-HA- g-PBLG could be effectively controlled by varying the initial ratio of BLG-NCA to Sr10-HA-NH₂. The microcarriers exhibited a highly porous and interconnected microstructure with the porosity of about 90% and overall density of 1.03-1.06 g/cm³. Also, the degradation rate of Sr10-HA-PBLG microcarriers could be effectively controlled and long-term Sr²⁺ release was obtained. The Sr10-HA-PBLG microcarriers allowed cells adhesion, infiltration, and proliferation and promoted the osteogenic differentiation of rabbit adipose-derived stem cells (ADSCs). Successful healing of femoral bone defect was proved by injection of the ADSCs-seeded Sr10-HA-PBLG microcarriers in a rabbit model.

Electron probe micro-analysis reveals the complexity of mineral deposition mechanisms in urinary stones

Urinary stones are complex mineralogical formations in the urinary system often impairing the kidney function. Several studies have attempted to understand the mechanisms of stone formation and growth; however, it remains to be fully explored. Here, we present a detailed investigation on the morphological and mineralogical characterizations of urinary stones. Structural properties of different types of urinary stones were done by X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and field-emission scanning electron microscope (FE-SEM) analyses. X-ray maps of major and the trace elements were obtained using electron microprobe (EPMA) technique. Basic metabolic panel and urinary parameters of the patients were used for comparing mineral compositions among stone types. The study included five major types of stones identified based on the FTIR spectra. FTIR and XRD helped in identifying the major components of these stones. FE-SEM images revealed distinct microstructure and morphology of the stones among the stone types. EPMA analysis showed the presence of many metals other than calcium and certain non-metals within the urinary stone matrix at measurable levels, sometimes with distinct distribution patterns. The study demonstrates the characteristic micro-structure, morphology, distribution, and composition of elements in different stone types. Findings of the study provide scope for understanding the complex mechanisms involved in the urolithogenesis and association of trace elements in it.

Intake of Trace Metals and the Risk of Incident Kidney Stones

PURPOSE

The association between the intake of trace metals and the risk of incident stones has not been longitudinally investigated.

MATERIALS AND METHODS

We performed a prospective analysis of 193,551 participants in the Health Professionals Follow-up Study, and the Nurses' Health Study I and II. During a followup of 3,316,580 person-years there was a total of 6,576 incident stones. We used multivariate regression models to identify associations of the intake of zinc, iron, copper and manganese with the risk of stones. In a subset of participants with 24-hour urine collections we examined the association between the intake of trace metals and urine composition.

RESULTS

After multivariate adjustment total and dietary intakes of zinc and iron were not significantly associated with incident stones. A higher intake of manganese was associated with a lower risk of stones. The pooled HR of the highest quintile of total manganese intake compared with the lowest intake was 0.82 (95% CI 0.68-0.98, p = 0.02). Total but not dietary copper intake was marginally associated with a higher risk of stones (pooled HR 1.14, 95% CI 1.02-1.28, p = 0.01). There were no statistically significant associations of the total intake of manganese and copper with urinary supersaturation.

CONCLUSIONS

Zinc and iron intake was not associated with a risk of stones. Copper intake may be associated with a higher risk in some individuals. Higher total manganese intake was associated with a lower risk of stones but not with traditional 24-hour urinary composite markers of stone risk. Further research is needed to elucidate the mechanisms by which manganese may reduce kidney stone formation.

Dietary Zinc and Incident Calcium Kidney Stones in Adolescence

PURPOSE

We determined the association between dietary zinc intake and incident calcium kidney stones in adolescents. We also examined the relationship between dietary zinc intake and urinary zinc excretion between cases and controls.

MATERIALS AND METHODS

We conducted a nested case-control study within a large pediatric health care system. Three 24-hour dietary recalls and spot urine chemistry analyses were obtained for 30 participants 12 to 18 years old with a first idiopathic calcium based kidney stone and 30 healthy controls matched for age, sex, race and month of enrollment. Conditional logistic regression models were used to estimate the association between daily zinc intake and incident calcium kidney stones, adjusting for dietary phytate, protein, calcium, sodium and oxalate. Multivariable linear regression was used to estimate the association between dietary and urine zinc, adjusting for urine creatinine and dietary phytate and calcium.

RESULTS

Cases had lower daily zinc intake (8.1 mg) than controls (10 mg, p = 0.029). Daily zinc intake of boys and girls with calcium stones was 2 mg and 1.2 mg less, respectively, than the daily intake recommended by the Institute of Medicine. Odds of incident stones were reduced by 13% for every 1 mg increase in daily zinc intake (OR 0.87, 95% CI 0.75-0.99). There was an estimated 4.5 μg/dl increase in urine zinc for every 1 mg increase in dietary zinc (p = 0.009), with weak evidence of a smaller increase in urine zinc in cases than in controls (interaction p = 0.08).

CONCLUSIONS

Decreased dietary zinc intake was independently associated with incident calcium nephrolithiasis in this population of adolescents.

The systematic classification of urinary stones combine-using FTIR and SEM-EDAX

BACKGROUND

To explore underlying mechanism of urinary stones formation, the composition and microstructure of urinary stones were analyzed systematically with a large sample study from China.

MATERIALS AND METHODS

A total of 2437 urinary stones were obtained from the urology department at our Hospital. The composition of the stones was analyzed by Fourier transform infrared spectroscopy (FTIR). Meanwhile, the microstructure and element distribution were observed with scanning electron microscopy combined with element distribution analysis (SEM-EDAX).

RESULTS

Urinary stones were classified into eight types, that were consisted of calcium oxalate stones (1301/2437, 53.39%), calcium phosphate stones (131/2437, 5.38%), anhydrous uric acid stones (434/2437, 17.81%), magnesium ammonium phosphate stones (12/2437, 0.49%), sodium urate stones (5/2437, 0.21%), brushite stones (4/2437, 0.16%), cystine stones (3/2437, 0.12%) and mixed stones (547/2437, 22.45%, ten subtypes were included). Under SEM, they displayed distinct microstructures: plank-like, brick-like, polyhedron or paliform crystals for calcium oxalate stones, similar sized echin-sphere or rough bulbiform or tree bark-like crystals for calcium phosphate stones, rotten-wood-like or petrous crystals for anhydrous uric acid stones, globular or gallet-like crystals for magnesium ammonium phosphate stones, sawdust-like crystals for sodium urate stones, broken-wood-like crystals for brushite stones, stacking hexagonal cystine crystals for cystine stones, and two or more of the above crystals for mixed stones. Meanwhile, they also presented distinct elemental composition and distribution by EDAX.

CONCLUSIONS

Urinary stones can be classified into eight types, and exhibit a diversity of microstructure and elemental compositions in China. The formation process of different types of urinary stones may be diverse.

Effects of plant polysaccharides with different carboxyl group contents on calcium oxalate crystal growth

The effects of five plant polysaccharides (PPSs) with molecular weights of ∼4000 Da and different carboxylic group (–COOH) contents on the crystal growth of calcium oxalate (CaOx) were comparatively studied.

[The role of physicochemistry in urology and nephrology, selected results obtained during the last ten years]

INTRODUCTION

The presence of pathological calcifications, which can be either concretions or ectopic call for physicochemical characterisation techniques in order to define a significant diagnosis. The aim of this review is to present a set of characterisation techniques able to describe at the micrometer scale their structural and chemical characteristics and show their place at the hospital.

METHOD

Results already published in the last ten years based on characterisation techniques present in laboratories or specific to large-scale instruments are presented. Their usefulness for the clinician is discussed.

RESULTS

The presence and role of heavy metals in urinary stones through data collected through μX-ray fluorescence is debated. If these data suggest a simple substitution process of calcium, recent data suggest that weddellite is associated to a Zn-rich environment, partly favoured by an inflammation process. Investigation on the chemistry and the structure of unusual deposits in kidney biopsies show a great chemical diversity of ectopic calcifications. Such diversity shows that staining procedures to characterize such deposits are obsolete. Finally, several diseases which can be assessed through techniques specific to large-scale instruments and defined by the clinician are presented.

CONCLUSION

The chemical and structural complexity of pathological calcifications call for a characterization through physicochemical techniques. Only such approach allows the clinician to define a significant diagnosis and to care the patient.