Human Stones Research Articles

Optimization of Plant Oxalate Quantification and Generation of Low-Oxalate Maize (Zea mays L.) through O7 Overexpression.

Oxalate, the simplest dicarboxylic acid, is a prevalent antinutrient that chelates with various metals and can lead to the formation of kidney stones in humans. The accurate detection of the oxalate concentration in food and the cultivation of low-oxalate crops are important for enhancing public health. In this study, we established a high-throughput and highly sensitive technique for oxalate detection using ultra-high-performance liquid chromatographic-triple quadrupole tandem mass spectrometry (UPLC-QqQ-MS/MS). Additionally, we overexpressed the gene O7, which encodes oxalyl-CoA synthetase in the maize oxalate degradation pathway, resulting in O7-OE lines. By employing the UPLC-QqQ-MS/MS method to measure oxalate levels in these transgenic lines, we observed that the oxalate content in the kernels of O7-OE lines was reduced by approximately 43%, with a concurrent increase in some micronutrients such as zinc. Importantly, the transgenic maize showed normal seed storage compound accumulation or other agronomic characteristics. In summary, we developed a high-throughput detection method that advances oxalate measurement. Furthermore, by generating new maize germplasm with diminished oxalate, our work offers potential health advantages to consumers.

Comparison of cat stone matrix and cat urine proteomes to human calcium oxalate stone matrix and urine proteomes.

Cat calcium oxalate monohydrate kidney stone matrix proteome showed great similarity to human calcium oxalate monohydrate stone matrix proteome, but inference of mechanistic similarity was limited by the absence of cat urine proteomic data. In this study, urine proteome distributions were measured by the same methods in 7 healthy cats for comparison to both the published human urine and cat calcium oxalate stone matrix proteomes to assess for similar enrichment patterns in both species. Furthermore, proteomic distributions were determined in cat struvite stone matrix to test for similarity to calcium oxalate monohydrate stone matrix and urine proteomes. Cat urine proteins demonstrated a similar distribution of abundance as a function of isoelectric points or net charge to human urine samples, and consequently the similarly altered patterns of protein distributions seen in calcium oxalate monohydrate stone matrix seen from both cat and human stones likely derives from the same preferential adsorption mechanism. Furthermore, the fact that protein abundance patterns seen in cat struvite stone matrix samples differ from both urine and calcium oxalate monohydrate stone matrix proteomes in systematic ways suggests that a combination of protein-protein and protein crystal interactions underly the formation of the crystal aggregates that comprise stones.

Past human decision-making based on stone tool performance: Experiments to test the influence of raw material variability and edge angle design on tool function

One of the main interests in the interpretation of the archaeological record and its variability within and through time and space is the production and use of past human stone tool technologies. Tool design and function are inevitably intertwined and strongly related to tool use. Understanding tool design provides information about early human technological adaptations and reflects human behaviour in the sense of conscious or unconscious decision-making. Nevertheless, the reason for major changes (including novelties, innovations, and loss) in past human stone tool technology is still poorly understood. A comprehensive approach focusing on tool function (What was the tool meant for?) and use (What was the tool used for?) can help to overcome this gap. While tool function (including performance) can be investigated experimentally, tool use can be addressed with use-wear analyses. These questions can be best investigated on technological systems showing little tool variability but strong evidence of maintenance and long-term use, such as Middle Palaeolithic industries.The Late Middle Palaeolithic record of Central and Eastern Europe is marked by the emergence of an asymmetric tool-type called Keilmesser (bifacial backed knives). Due to their sophisticated morphology, Keilmesser as a case study offer the potential to address aspects of raw material selection, tool production, maintenance, and reworking.This paper presents the results of an experiment designed to study the tool performance of Keilmesser from three archaeological sites, namely Balver Höhle, the Upper site of Buhlen and Grotte de Ramioul by testing raw material, edge angle and movement as independent variables. A highly controlled, sequential experiment was conducted using a mechanical device performing unidirectional cutting and carving movements on hard contact material. Results demonstrate the possibility to perform the mentioned task with 35° and 45° edge angles, maintaining function, albeit at differing levels of efficiency. The data has a direct impact on the interpretation of the archaeological assemblages regarding aspects such as stone tool morphology and resharpening. At the same time, the study highlights the importance of raw material analysis to understand the variability in the archaeological record and the implications on past human decision-making strategies.

Proof-of-concept for a novel nanotechnology-based treatment for urolithiasis

Proof-of-concept of photonic lithotripsy in an in vitro setting and its ability to fragment the most common stone types is demonstrated. Effectiveness of different classes of photonic nanoparticles in fragmenting human stones is assessed. De-identified human stones were collected after institutional approval. Stones of a size range between 2–4 mm were rehydrated in simulated urine for 24 h. Stones were then coated with a solution of nanoparticles prior to activation with either a 785 nm or 1320 nm near-infrared energy source. Photonic lithotripsy achieved greater than 70% success rate in fragmentating calcium oxalate monohydrate stones using carbon-based nanoparticles for both near-infrared wavelengths. For gold-based nanoparticles, there was a similar success rate with the 785 nm wavelength but a significant decrease when using the 1320 nm wavelength energy source. All stones fragmented with the energy source at a distance ≥ 20 mm from the stone’s surface. Limitations include the use of mixed-composition stones, a lack of complete stone immersion in liquid during treatment, and smaller stone size. Different classes of nanoparticles when excited with a near-infrared energy source can fragment common stone types in vitro. This technology has the potential to change the way we approach and treat patients with urolithiasis in a clinical setting.

Petrified

Set in a rural mining town in nineteenth-century Spain, Benito Pérez Galdós’s novel Marianela enfolds a complex mediation on the relationship between humans ( bios ) and stones ( geos ) in the wake of industrial modernization. At the heart of this natural world are Marianela, an unsightly lumpen-proletariat, her blind bourgeois companion Pablo, and Celipín, a child miner, all raised in proximity to a zinc sulfate mine and all compared to the geological matter of the earth. Working at the intersection of disability studies, ecocriticism, and theories of biopolitics, the article examines the relationship between disability and rurality. The novel’s unconventional treatment of disabled and socially marginalized characters as human stone sheds light on a process the article terms petrification: the mutual debilitation of the bodies of nature and human bodies, exploited by capitalism and ableism alike.

How much energy do we need to ablate 1 cubic millimeter of stone during Thulium Fiber Laser lithotripsy? An in vitro study.

Both Holmium:yttrium-aluminium-garnet (Ho:YAG) laser and Thulium Fiber Laser (TFL) can effectively treat all urinary stone types. This in vitro study evaluated the ablation volume per pulse (AVP) and required energy needed to ablate 1mm3 (RE, J/mm3) of various stone types at different laser settings with TFL. 272-µm core-diameter laser fibers (Boston Scientific©) were connected to a 50Watts TFL generator (IPG®). An experimental setup immerged human stones of calcium oxalate monohydrate (COM), uric acid (UA), and cystine (CYS) with a single pulse lasing emission (0.5/0.8/1J), in contact mode. Stones were dried out before three-dimensional scanning to measure AVP and deduce from the pulse energy (PE) and AVP the RE. A direct comparison with known Ho:YAG's AVP and RE was then carried out. AVP for COM stones was significantly greater than those for CYS stones and similar to UA stones (p = 0.02 and p = 0.06, respectively). If AVP increased with PE against COM and UA stones, AVP decreased against CYS stones. 1J PE resulted in a threefold lower RE compared with other PE for COM stones. On the contrary, RE for CYS increased with PE, whereas PE did not had influence on RE for UA. TFL was associated with greater AVP for COM, but lower for UA and CYS stones compared to Ho:YAG laser. This in vitro study firstly describes the ablation volume per pulse and required energy to treat a cubic millimeter of three frequent human stone types, and suggest TFL could not be suited for cystine. Therefore, stone composition could be considered when choosing the laser source for lithotripsy.

Using the overall variation trend and fitting of Na-feldspar crystal plane spacing after chemical corrosion to prevent rock disasters

Sulfuric acid pollution, caused by acid rain, acidic wastewater, and natural acidic wastewater from mines, poses a significant risk to the stability of natural stone slopes and human stone structures. This study aims to develop a non-mechanical testing method for assessing the degree of acid corrosion in rocks, facilitating early intervention by safety engineers. The proposed method involves using XRD to measure the crystal plane spacing of Na-feldspar corroded by different concentrations of sulfuric acid, followed by mathematical analysis to determine the overall deviation degree of the crystal plane spacing. Four Deviation indices were defined to characterize the degree of acid corrosion, and all four indices increased with increasing acidity. By comparing trend charts, an optimized number of crystal planes for analysis was identified. Selecting the 100 sets of data with the largest spacing yielded similar trend results as selecting all the data. In addition, five different fitting methods were compared, and the power function fitting of Weighted Sum of squares of cumulative errors (WSSCE) was found to provide the optimal empirical formula, with a correlation coefficient exceeding 0.98.

Microbial Degradation Of Calcium Oxalate And Its Potential Application

Calcium oxalate is a naturally occurring compound found in various plants and minerals, and its accumulation in the kidney leads to the formation of kidney stones in humans. One of the main causes of kidney stone formation is a decrease in the number of intestinal microbiota which are capable of degrading calcium oxalate. This study focuses on bacterial degradation of calcium oxalate accumulated in humans. Searching for Calcium oxalate degrading strain with high degrading activity has become one of the priorities from the context of research. The study aimed to isolate and characterize microorganisms which are capable of degrading calcium oxalate. Calcium oxalate degrading microorganisms were isolated from faecal samples by using MRS-calcium oxalate medium. Calcium oxalate degrading bacteria were identified on the basis of colour reduction on calcium oxalate medium plate after the incubation period. The morphological and biochemical characterization of isolates were studied. Quantitative determination of degradation was performed by using an indole assay. The activity of isolates was observed by the degradation of kidney stones. Isolates showed better results for degradation of kidney stones after 2 weeks of the incubation period.

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.

Influences of changes in pH, temperature, and particle size on surface reaction resistance and diffusion resistance in the struvite dissolution process

Struvite (MgNH4PO4·6 H2O，MAP), a type of high-quality, slow-release fertilizer, is the main component of urinary stones in animals and humans and causes scale formation in industrial pipes. Therefore, MAP dissolution is an important research topic. Herein, MAP dissolution experiments are performed and a thermodynamic model is developed to evaluate the influences of pH, temperature (T), and particle size (Ps) on surface reaction resistance (1/ks) and diffusion resistance (1/kd). The results show that MAP solubility decreases with an increase in pH and the effects of pH change are more obvious than those of T or Ps. The total resistance (1/kT) of MAP dissolution increases with pH increase, Ps growth, or T reduction. The comparison of 1/ks and1/kd reveals surface reaction as the MAP dissolution control step and indicates a linear relation among 1/ks, 1/kd, and the natural logarithm of Ps at pH 7.0.

Ablation rates with Holmium:YAG and Thulium Fiber Laser: Influence of the stone phantom homogeneity. An in vitro study.

The lithotripsy efficiency (LE) in vitro study requires artificial or human stone samples (AS, HS). With the development of dusting lithotripsy, less ex vivo HS are available. We aimed to compare Thulium Fiber Laser (TFL) and Holmium:YAG (Ho:YAG)'s LE and define the most accurate LE parameter. Hard and soft homogenous- and heterogenous-AS (Ho-AS, He-AS) were made to reproduce calcium-oxalate monohydrate and uric acid stones, respectively by a rapid or slow brewing of BegostonePlus (Bego) and distilled water. One hundred and fifty and 272μm-laser fibers, connected to 50W-TFL and 30W-HoYAG generators, compared three settings for TFL (FD: 0.15J/100Hz; D: 0.5J/30Hz; Fr: 1J/15Hz) and two for Ho:YAG (D-Fr). An experimental setup consisted in immerged 10mm cubic stone phantoms with a 20 seconds' lasing spiral, in contact mode, repeated four times. Stones were dried, weighted and μ-scanned (ablation weight and volume [AW and AV]). With He-AS, dusting AV were four- and three-fold higher with TFL compared to Ho:YAG against hard and soft (P<0.05). In fragmentation, AV were two-fold higher with TFL compared to Ho:YAG against hard (P<0.05) and soft (P<0.05). Experiments with Ho-AS were associated with non-significant differences when comparing TFL-150μm and TFL-272μm. The ablation weight-volume correlation coefficients was higher with Ho-AS than with He-AS (P<0.0001), and with hard than soft AS. If the LE can be estimated by the AW with hard AS, this approximation is not consistent for soft AS. TFL presented higher ablation rates than Ho:YAG, significant with He-AS. If the AW is acceptable and less expensive for hard Ho-AS, AV are more accurate for He-AS, which are suggested to imitate closely HS.

English

The influence of aqueous extract of millet on the crystallization and the dissolution of calcium oxalate (CaOx) crystals were investigated in detail under supersaturated and artificial urinary circumstances in order to understand the effect of the water-soluble components of millet on CaOx kidney stones in humans. To investigate the inhibition effect, different volumes of millet extract were added separately to the combined supersaturated and artificial urinary solutions while the crystal deposition process was monitored by UV-Vis and conductivity measurements. The harvested crystals were characterized by FT-IR, SEM, TGA, XRD and redox titrations so as to determine the structure and the morphology of CaOx crystals formed. Our findings indicate that the crystals obtained from inhibition and dissolution experiments were mainly calcium oxalate monohydrate (COM), the thermodynamically more stable phase. Furthermore, the results show that the millet extract has a promising inhibition effect in the supersaturated solution and in artificial urinary circumstances showing ~34 and ~26% decrease in crystal deposition, respectively, with 50 mL of millet extract compared to control experiments. The dissolution effect of millet extract is far superior to that of the inhibition effect. One gram of COM crystals completely disappeared when the crystals were washed ten times with 300 mL millet extracts. Under the same conditions, the control experiment showed only ~44% dissolution of COM crystals. Further investigations conducted with actual kidney stones under artificial urinary circumstances showed approximately 20% dissolution when washings were carried out using 300-mL portions of millet over one week. This novel finding may shed the light on the possible use of millet as a potential natural antiurolithic remedy to treat CaOx kidney stones in humans. Key words: Calcium oxalate, kidney stones, millet, inhibition, dissolution effect.

New perspectives on an old grouping: The genomic and phenotypic variability of Oxalobacter formigenes and the implications for calcium oxalate stone prevention.

Oxalobacter formigenes is a unique bacterium with the ability to metabolize oxalate as a primary carbon source. Most kidney stones in humans are composed of calcium and oxalate. Therefore, supplementation with an oxalate-degrading bacterium may reduce stone burden in patients suffering from recurrent calcium oxalate-based urolithiasis. Strains of O. formigenes are divided into two groups: group I and group II. However, the differences between strains from each group remain unclear and elucidating these distinctions will provide a better understanding of their physiology and potential clinical applications. Here, genomes from multiple O. formigenes strains underwent whole genome sequencing followed by phylogenetic and functional analyses. Genetic differences suggest that the O. formigenes taxon should be divided into an additional three species: Oxalobacter aliiformigenes sp. nov, Oxalobacter paeniformigenes sp. nov, and Oxalobacter paraformigenes sp. nov. Despite the similarities in the oxalyl-CoA gene (oxc), which is essential for oxalate degradation, these strains have multiple unique genetic features that may be potential exploited for clinical use. Further investigation into the growth of these strains in a simulated fecal environment revealed that O. aliiformigenes strains are capable of thriving within the human gut microbiota. O. aliiformigenes may be a better therapeutic candidate than current group I strains (retaining the name O. formigenes), which have been previously tested and shown to be ineffective as an oral supplement to mitigate stone disease. By performing genomic analyses and identifying these novel characteristics, Oxalobacter strains better suited to mitigation of calcium oxalate-based urolithiasis may be identified in the future.

The assistant effects of porcine fibrin sealant in improving stone clearance rate in flexible ureteroscopy lithotripsy in ex vivo porcine kidney model

Objectives: To investigate the feasibility of using a porcine fibrin sealant to wrap and remove kidney calculi fragments through an isolated porcine kidney model. Methods: In the isolated porcine kidney stone model (implanted with 100 mg, air dried, ≤1 mm human stone fragments, n=6;implanted with 100 mg, air dried, ≤3 mm human stone fragments, n=6), the ureteral soft mirror combined with the 12/14Fr UAS was used to test the effect of stone extraction using only two stone extraction methods: basket extraction (control group, ≤1 mm stone fragments, n=3; ≤3 mm stone fragments, n=3) and basket-sealant extraction (test group, ≤1 mm stone fragments, n=3; ≤3 mm stone fragments, n=3). Compare the stone removal rate and operation time of the two stone retrieval methods. The sealant was put into urine of normal human and observed. Results: Porcine Fibrin Sealant can form a gel in saline and urine and adhere and wrap stone fragments. The time of procedures of test (basket-sealant) and control (basket) group in kidneys implanted with ≤ 1 mm stone fragments were (14.0±4.2) and (29.0±0.7)min (P<0.05) stone clearance rates were (90.9±1.4)% and (48.4±15.7)% (P<0.05), respectively. In kidneys implanted with ≤ 3 mm fragments, time of procedures were (12.8±4.0) and (30.0±0)min (P<0.05) Stone clearance rates were (91.1±5.0)% and (20.7±8.0)% (P<0.05). The Sealant dissolves by itself in normal human urine and normal saline at 37 ℃ for 24 hours. Conclusion: The appropriate concentration of Porcine Fibrin Sealant assisted stone retrieval may become a new method for removing small stone fragments in retrograde intrarenal surgery.

MP14-10 MECHANISMS OF PULSE MODULATED HOLMIUM:YAG LITHOTRIPSY: PULSE TRANSMISSION AND SHOCK WAVE PRESSURE

You have accessJournal of UrologyCME1 May 2022MP14-10 MECHANISMS OF PULSE MODULATED HOLMIUM:YAG LITHOTRIPSY: PULSE TRANSMISSION AND SHOCK WAVE PRESSURE Jason King, Nitesh Katta, Joel Teichman, James Tunnell, and Thomas Milner Jason KingJason King More articles by this author , Nitesh KattaNitesh Katta More articles by this author , Joel TeichmanJoel Teichman More articles by this author , James TunnellJames Tunnell More articles by this author , and Thomas MilnerThomas Milner More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002543.10AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Previous Ho:YAG lithotripsy studies suggest that the dominant mechanism is photothermal. Recent studies have highlighted ablation through water jet impingement or by cavitation induced shock waves. If the photothermal mechanism is dominant, an optimized pulse mode would deliver the most photons into the stone for lithotripsy. If the photoacoustic mechanism is dominant, then an optimized pulse mode would produce a high-pressure cavitation induced shock wave. In this study we compared the photon transmission through a 1 mm water layer and the peak pressures for a variety of Ho:YAG temporal pulse modes. Results are compared to experimentally measured ablation volumes to better understand the mechanisms in Ho:YAG lithotripsy. METHODS: Five pulse modes from a clinical Ho:YAG laser (MOSES Pulse 120H, Lumenis) were compared, each with a pulse energy of 1J: short (SP), medium (MP), and long (LP) pulse durations, Moses Distance (MD), and Moses Contact (MC). A 230 µm optical fiber was placed 1 mm from a glass surface at normal incidence. A power meter (PM10, Coherent) directly behind the glass surface measured the average power for a train of pulses. The average pulse energy transmitted through 1 mm water was calculated by correcting for glass absorption and reflection loss. Measurements were repeated 5 times for each pulse mode. Next, the fiber was placed 5 mm above a pressure sensor (112A21, PCB Piezotronics) at normal incidence. Pressure transients were recorded and corrected for a separation distance of 1 mm. Results were compared with ablation crater volume data from BegoStone phantoms and human stones with single 1J short and 1J MD pulses per location with a fiber separation distance of 1 mm. RESULTS: Transmitted pulse energy and peak pressures are shown in Table 1. Ablation volume results in water show significantly larger crater volumes for MD vs. SP for Begstone and struvite stones. No statistical significance was observed between MD and SP volumes for COM or uric acid stones. CONCLUSIONS: Experimental data suggests stone ablation is primarily photothermal. SP pulse mode delivery resulted in similar photon transmission and 5.5X greater peak pressure compared to MD and resulted in similar or smaller ablation craters. Enhanced ablation from the tested pulse modulation is composition specific and requires further experimentation with human stones. Source of Funding: Work was partially funded by Lumenis © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e235 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jason King More articles by this author Nitesh Katta More articles by this author Joel Teichman More articles by this author James Tunnell More articles by this author Thomas Milner More articles by this author Expand All Advertisement PDF DownloadLoading ...

Evaluation of antiurolithiatic and antioxidant activity of the Egyptian Pluchea dioscoridis L. leaves extracts in vitro

Bioactive compounds in medicinal plants are believed to be an important in the folk of medicine. Many efforts have been done to discover the safe medical treatment instead of chemical drugs which have a harmful effect on the human body. In the present study the crude extracts of Pluchea dioscoridis were tested to evaluate their bioactive compounds (total phenolic and flavonoid compounds) and their effects as antiurolithiasis of human stones (calcium triphosphate (CTP), cholesterol and calcium oxalate monohydrate (COM) besides, their antioxidant activities. The measured total phenolic compounds content in the methanol, ethyl acetate, and water extracts of Pluchea dioscoridiswere found to be equal to 11.842, 9.047, and 8.126 mg/g, respectively. Also, the contents of the total flavonoid compounds (total phenol) were 19.018, 15.312, and 14.022mg/g for methanol, ethyl acetate, and aqueous extracts of P.dioscoridis, respectively. The results showed that all extracts of P. dioscoridis have a significant inhibitory effect on the dissolution of the three investigated types of formed stones (CTP, cholesterol, and COM). The inhibition effect was in the order methanol > ethyl acetate > water extract. Also, it was found that all extracts for P.dioscoridis were exhibited 2, 2, diphenyl-1-picryl hydrazil (DPPH) radical, reducing power, ABTS∙+ radical, Nitric oxide radical scavenging activity. Methanol extract of P. dioscoridis exhibited the highest scavenging activity compared to ethyl acetate and water extracts. Refaat Ahmed Saber

First fragmentation of stones in humans by burst wave lithotripsy

We report stone comminution in the first 18 human subjects by burst wave lithotripsy (BWL). Subjects undergoing clinical ureteroscopy (URS) for at least one stone ≤12 mm on computed tomography (CT) are recruited. During the planned URS, either before or after ureteroscope insertion, BWL is administered with a handheld probe for 10 min, and any stone fragmentation and tissue injury are observed. The primary effectiveness outcome is the volume percent comminution of the stone into fragments ≤2 mm, where fragment volume is determined by μCT of basketed fragments or image processing of the URS video using the laser fiber as a size reference. The primary safety outcome is independent, blinded grading of tissue injury from the URS video. Overall, 10 of 22 stones (45%) fragmented completely in 10 min. 64% and 73% were projected to fragment completely in 15 and 40 min, respectively. For reference, shock wave lithotripsy success is about 65% to fragments ≤4 mm in 40 min. Of the other six stones, one was larger than the beamwidth, two were smaller than the wavelength, and the ureteroscope introduced air bubbles around another. Only mild reddening with some hematuria was observed ureteroscopically. [Work supported by NIH-P01-DK04331.]

Effect of antibiotic treatment on Oxalobacter formigenes colonization of the gut microbiome and urinary oxalate excretion

The incidence of kidney stones is increasing in the US population. Oxalate, a major factor for stone formation, is degraded by gut bacteria reducing its intestinal absorption. Intestinal O. formigenes colonization has been associated with a lower risk for recurrent kidney stones in humans. In the current study, we used a clinical trial of the eradication of Helicobacter pylori to assess the effects of an antibiotic course on O. formigenes colonization, urine electrolytes, and the composition of the intestinal microbiome. Of 69 healthy adult subjects recruited, 19 received antibiotics for H. pylori eradication, while 46 were followed as controls. Serial fecal samples were examined for O. formigenes presence and microbiota characteristics. Urine, collected serially fasting and following a standard meal, was tested for oxalate and electrolyte concentrations. O. formigenes prevalence was 50%. Colonization was significantly and persistently suppressed in antibiotic-exposed subjects but remained stable in controls. Urinary pH increased after antibiotics, but urinary oxalate did not differ between the control and treatment groups. In subjects not on antibiotics, the O. formigenes-positive samples had higher alpha-diversity and significantly differed in Beta-diversity from the O. formigenes-negative samples. Specific taxa varied in abundance in relation to urinary oxalate levels. These studies identified significant antibiotic effects on O. formigenes colonization and urinary electrolytes and showed that overall microbiome structure differed in subjects according to O. formigenes presence. Identifying a consortium of bacterial taxa associated with urinary oxalate may provide clues for the primary prevention of kidney stones in healthy adults.

Analysis of Human Urinary Stones and Gallstones by Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy

Analysis of Human Urinary Stones and Gallstones by Fourier Transform Infrared Attenuated Total Reflectance Spectroscopy

Animal models of naturally occurring stone disease.

The prevalence of urolithiasis in humans is increasing worldwide; however, non-surgical treatment and prevention options remain limited despite decades of investigation. Most existing laboratory animal models for urolithiasis rely on highly artificial methods of stone induction and, as a result, might not be fully applicable to the study of natural stone initiation and growth. Animal models that naturally and spontaneously form uroliths are an underused resource in the study of human stone disease and offer many potential opportunities for improving insight into stone pathogenesis. These models include domestic dogs and cats, as well as a variety of other captive and wild species, such as otters, dolphins and ferrets, that form calcium oxalate, struvite, uric acid, cystine and other stone types. Improved collaboration between urologists, basic scientists and veterinarians is warranted to further our understanding of how stones form and to consider possible new preventive and therapeutic treatment options.