Kidney stones probably grow during crystalluria by crystal sedimentation and aggregation (AGN) on stone surfaces. This process has to occur within urinary transit time (UT) through the kidney before crystals are washed out by diuresis. To get more information, we studied by spectrophotometry the formation and AGN of Ca oxalate (Ca Ox) crystals which were directly produced in urine of 30 stone patients and 30 controls by an oxalate (Ox) titration. Some tests were also performed after removing urinary macromolecules (UMs) by ultrafiltration. To induce rapid crystallization, high Ox additions (0.5-0.8 mM) were necessary. The most important finding was retardation of crystal AGN by UM. In urine of 63% of controls but only 33% of patients, no AGN was observed during an observation of 60 minutes (P < 0.05). Also growth and sedimentation rate of crystals were significantly reduced by UM. For stone metaphylaxis, especially for posttreatment residuals, avoiding dietary Ox excesses to prevent crystal formation in the kidney and increasing diuresis to wash out crystals before they aggregate are recommended.
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http://dx.doi.org/10.1155/2012/175843 | DOI Listing |
J Am Chem Soc
January 2025
Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States.
Here we demonstrate how a biologically relevant molecule, riboflavin (vitamin B2), operates by a dual mode of action to effectively control crystallization of ammonium urate (NHHU), which is associated with cetacean kidney stones. In situ microfluidics and atomic force microscopy experiments confirm a strong interaction between riboflavin and NHHU crystal surfaces that substantially inhibits layer nucleation and spreading by kinetic mechanisms of step pinning and kink blocking. Riboflavin does not alter the distribution of tautomeric urate isomers, but its adsorption on NHHU crystal surfaces does interfere with the effects of minor urate tautomer by limiting its ability to induce NHHU crystal defects while also suppressing NHHU nucleation and inhibiting crystal growth by 80% at an uncharacteristically low modifier concentration.
View Article and Find Full Text PDFGut Microbes
December 2025
Department of Urology, The Second Affiliated Hospital of Guangzhou Medical University, Guangzhou, Guangdong, China.
Hyperoxaluria, including primary and secondary hyperoxaluria, is a disorder characterized by increased urinary oxalate excretion and could lead to recurrent calcium oxalate kidney stones, nephrocalcinosis and eventually end stage renal disease. For secondary hyperoxaluria, high dietary oxalate (HDOx) or its precursors intake is a key reason. Recently, accumulated studies highlight the important role of gut microbiota in the regulation of oxalate homeostasis.
View Article and Find Full Text PDFPediatr Nephrol
January 2025
University Medical Center Hamburg-Eppendorf, University Children's Hospital, Martinistrasse 52, Hamburg, 20246, Germany.
Background: Primary hyperoxaluria type 1 (PH 1) is a rare genetic condition due to mutations in the AGXT gene. This leads to an overproduction of oxalate in the liver. Hyperoxaluria often causes kidney stones, nephrocalcinosis, and chronic kidney disease.
View Article and Find Full Text PDFFront Bioeng Biotechnol
January 2025
Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Potsdam, Germany.
Background: Bacteria in physiological environments can generate mineralizing biofilms, which are associated with diseases like periodontitis or kidney stones. Modelling complex environments presents a challenge for the study of mineralization in biofilms. Here, we developed an experimental setup which could be applied to study the fundamental principles behind biofilm mineralization on rigid substrates, using a model organism and in a tailored bioreactor that mimics a humid environment.
View Article and Find Full Text PDFCureus
December 2024
Urology, Hospital General Dr. Agustín O'Horán, Mérida, MEX.
A supernumerary kidney is a rare birth defect where an extra kidney is present. This extra kidney has its own separate outer covering, blood supply, and collection system. Normally, percutaneous nephrolithotomy (PCNL) is the treatment of choice for large kidney stones, but its ideal use for supernumerary kidneys is unknown.
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