Carbonate Apatite Research Articles

MP16-11 CARBONATE APATITE NEPHROLITHIASIS

You have accessJournal of UrologyCME1 Apr 2023MP16-11 CARBONATE APATITE NEPHROLITHIASIS Nick Dean, Jenny Guo, and Amy Krambeck Nick DeanNick Dean More articles by this author , Jenny GuoJenny Guo More articles by this author , and Amy KrambeckAmy Krambeck More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003236.11AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Carbonate apatite (CA) stones are commonly referred to as infection stones given their formation in the presence of bacterial infection and their association with positive urine and stone cultures. Anecdotally at our institution, we observed patients who were found to have CA stones on post-operative stone analysis without positive stone cultures, positive pre-operative urine cultures, or a history of urinary tract infections (UTIs). The aim of our study is to characterize patients with CA stones, with and without evidence of infection, and examine their clinical outcomes. METHODS: We retrospectively identified patients in our prospectively maintained stone database who had undergone surgical treatment for calculi containing CA on final stone analysis. SPSS was used to perform descriptive statistics and two-tailed T tests (p<0.05). RESULTS: We identified 53 patients with CA stones from our database. Most patients were female (n=35, 66.0%) and had undergone percutaneous nephrolithomy (PCNL) (n=44, 83.0%). Mean follow-up was 13.8 months. Almost all patients with CA stones had a documented vitamin D deficiency (n=47, 88.7%) and were prescribed vitamin D supplementation (n=46, 86.8%). Patients had a mean pre-operative stone burden of 2.8 cm (range 0.5-20 cm) and over half of the patients had a positive pre-operative urine culture, post-operative stone culture, or history of UTIs (n=28, 52.8%). Patients with evidence of infection (infection stones) were more likely to have a GU anatomical abnormality (39% vs 4%, p<0.002), greater proportion of CA on stone analysis (51% vs 32%, p=0.037), hypocitraturia on 24-hour urine collection (85% vs 50%, p=0.06), and lower rates of freedom from next stone procedure (82% vs 96%, p=0.12). Patients with infection CA stones did not have longer lengths of stay, worse stone free rates, greater rates of ER presentations, or re-admission rates (all p>0.05) compared to patients without evidence of infection. CONCLUSIONS: Patients with CA stones have a high prevalence of vitamin D deficiency and prescribed vitamin D replacement. Patients with CA stones and evidence of infection tend to have higher proportions of CA on stone analysis, greater rates of hypocitraturia on 24-hour urine collections, and may have lower rates of freedom from subsequent stone treatment compared to patients without evidence of infection. Source of Funding: None © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e206 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Nick Dean More articles by this author Jenny Guo More articles by this author Amy Krambeck More articles by this author Expand All Advertisement PDF downloadLoading ...

LBA01-16 COMPARATIVE ANALYSES AND ABLATION EFFICACY OF THULIUM FIBER LASER BY STONE COMPOSITION

You have accessJournal of UrologyCME1 Apr 2023LBA01-16 COMPARATIVE ANALYSES AND ABLATION EFFICACY OF THULIUM FIBER LASER BY STONE COMPOSITION Jeffrey Johnson, Miyad Movassaghi, David Han, Srinath-Reddi Pingle, Justin Lee, Prakash Gorroochurn, James Williams, Michael Schulster, and Ojas Shah Jeffrey JohnsonJeffrey Johnson More articles by this author , Miyad MovassaghiMiyad Movassaghi More articles by this author , David HanDavid Han More articles by this author , Srinath-Reddi PingleSrinath-Reddi Pingle More articles by this author , Justin LeeJustin Lee More articles by this author , Prakash GorroochurnPrakash Gorroochurn More articles by this author , James WilliamsJames Williams More articles by this author , Michael SchulsterMichael Schulster More articles by this author , and Ojas ShahOjas Shah More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000003360.16AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: There is limited data on the ablation settings and photothermal effects of thulium fiber laser (TFL) lithotripsy across various stone compositions. We aim to identify settings by stone type that optimize efficiency and avoid undesirable effects (i.e. charring) during TFL lithotripsy. METHODS: Specimens of calcium oxalate monohydrate, calcium oxalate dihydrate, uric acid, struvite, cystine, carbonate apatite and brushite stones were ablated to ≤1mm residual fragments using 13 settings with the Coloplast© TFL Drive. Pre-ablation mass, post-ablation mass, ablation time and total energy were recorded. Samples were analyzed using FTIR spectroscopy and electron microscopy. RESULTS: Pulse duration impacted ablation effectiveness greatly with 75% of inadequate ablations occurring in medium or long pulse settings. Calcium oxalate dihydrate, cystine, and struvite ablated most efficiently with 0.2J×100Hz, short pulse. Calcium oxalate monohydrate ablated most efficiently with 0.4J×40Hz, short pulse. The average percent of mass lost during ablation was 57%; cystine averaged the highest at 71%. Charring was seen in 40% of stones, mostly in uric acid, cystine, and brushite stones. Electron microscopy of char demonstrated a porous melting effect. FTIR spectroscopy of brushite char demonstrated a chemical composition change to amorphous calcium phosphate. CONCLUSIONS: Our trial is the first in vitro trial on stone ablation efficacy by stone composition. Across all settings and stone types 0.05J×1000Hz was the most effective ablation setting, however this is above our clinically recommended power of <=20 W. When operating in the kidney and using clinically acceptable TFL settings to minimize the risk of thermal injury, we recommend starting with short pulse 0.2J×100Hz and 0.4J×40Hz to cover most stone types, and adjusting the settings based on visual ablation effects intraoperatively and the clinical scenario (e.g. limited irrigation flow, narrow infundibulum). Further investigation is needed to continue to optimize TFL stone treatment settings. Source of Funding: Coloplast © 2023 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 209Issue Supplement 4April 2023Page: e1183 Advertisement Copyright & Permissions© 2023 by American Urological Association Education and Research, Inc.MetricsAuthor Information Jeffrey Johnson More articles by this author Miyad Movassaghi More articles by this author David Han More articles by this author Srinath-Reddi Pingle More articles by this author Justin Lee More articles by this author Prakash Gorroochurn More articles by this author James Williams More articles by this author Michael Schulster More articles by this author Ojas Shah More articles by this author Expand All Advertisement PDF downloadLoading ...

A short note on bioglass in Periodontics.

Bone augmentation grafts may act as space-maintaining devices to allow coronal migration of periodontal progenitor cells. The ideal bone replacement graft should be able to trigger osteogenesis, cementogenesis and formation of a functional periodontal ligament. It has been theorized that bioactive glass, which is a ceramic has bioactive properties that guide and promote osteogenesis allowing rapid formation of bone. Bioactive glass consists of sodium and calcium salts, phosphates and silicon dioxide for dental applications. When this material comes into contact with tissue fluids, the surface of the particles becomes coated with hydroxy carbonate apatite, incorporates organic ground proteins such as chondroitin sulfate and glycosaminoglycans and attracts osteoblasts that rapidly form bone.

Evaluation of carbonate apatite as a bone substitute in rat extraction sockets from the perspective of mesenchymal stem cells.

Carbonate apatite (CO3Ap) is a major inorganic bone component and an effective bone substitute. To clarify the function of CO3Ap, we compared differences among CO3Ap, hydroxyapatite (HAp), and β-tricalcium phosphate (β-TCP) by focusing on mesenchymal stem cells (MSCs) that have a role in wound healing. For in vivo experiments, maxillary molars were removed and the bone substitute was inserted. MSC accumulation around extraction sockets was significantly promoted in CO3Ap and β-TCP groups. For in vitro experiments, MSCs were cultured with bone substitutes. The differentiation potential and amount of calcium deposition were significantly lower in CO3Ap and HAp groups than in the β-TCP group. Increases in insulin-like growth factor-I and vascular endothelial growth factor were found only in the CO3Ap group. CO3Ap-filled extraction sockets accumulated MSCs, and MSCs cultured in the presence of CO3Ap produced large amounts of growth factors. These results suggest that CO3Ap promotes healing of tooth extraction sockets.

Remineralization Potential of Three Restorative Glass Ionomer Cements: An In Vitro Study.

The aim of this in vitro study was to evaluate the remineralizing ability of three glass ionomers on demineralized dentin with different thicknesses and time periods. Fifty third molars were obtained and were sectioned into 1-, 2-, and 3-mm thick slices (n = 36 for each thickness). The specimens were demineralized with 18% EDTA for 2 h. From the glass ionomer cements (GICs) under study (Ketac Molar Aplicap, Equia Forte, or Riva Light Cure), 1 mm was placed over each slice, set, and preserved in PBS until observation after 1, 7, 14, and 28 days after placement. For each material, thickness, and time, three samples were prepared. Using Fourier Transform Infrared Spectrometry (FTIR), apatite formation was determined on the side opposite to that on which the material had been placed. By means of Energy Dispersive Spectroscopy (EDX), the changes in the Calcium/Phosphate (Ca/P) ratio were evaluated. These changes were compared between the different materials by means of a two-way ANOVA test, considering time and dentin thickness, for a significance level of p < 0.05. Results: FTIR showed a peak at 1420 cm-1, evidencing the presence of carbonated hydroxyapatite in all the materials after 14 days, which indicates that a remineralization process occurred. Riva Light Cure showed the most homogeneous results at all depths at 28 days. The Ca/P ratio was maximum at 7 days in 2 mm of dentin for Riva Light Cure and Equia Forte HT (3.16 and 3.07; respectively) and for Ketac Molar at 14 days in 1 mm (3.67). All materials induced remineralization. Equia Forte achieved the greatest effect at 2 mm and Ketac Molar at 1 mm, whereas Riva Light Cure showed similar results at all depths. In terms of Ca/P ratio, Equia Forte and Riva Light Cure remineralized best at 2 mm, whereas for Ketac Molar, it was 1 mm. Carbonate apatite formation was higher at 24 h and 7 days for Ketac Molar, whereas it decreased at 14 days for Ketac Molar and peaked in Riva Light Cure and Equia Forte.

Enhanced effect of a novel bioactive glass-ceramic for dental application.

Dental caries is the most common chronic disease in humans, caused by the acid produced by the microflora in the mouth that dissolves the enamel minerals. Bioactive glass (BAG) has been used in various clinical applications due to its unique bioactive properties, such as bone graft substitutes and dental restorative composites. In this study, we introduce a novel bioactive glass-ceramic (NBGC) prepared through a sol-gel process under a water-free condition. The anti-demineralization and remineralization effects of NBGC were evaluated by comparing the measurements of bovine enamel surface morphology, surface roughness, surface micro-hardness, enamel elements, and mineral content before and after related treatments with a commercial BAG. The antibacterial effect was characterized by minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC). Results showed that NBGC had greater acid resistance and remineralization potential compared to commercial BAG. The fast formation of a hydroxy carbonate apatite (HCA) layer suggests efficient bioactivity. In addition to its antibacterial properties, NBGC shows promise as an ingredient in oral care products that can prevent demineralization and restore enamel.

Bioactive Carbonate Apatite Cement with Enhanced Compressive Strength via Incorporation of Silica Calcium Phosphate Composites and Calcium Hydroxide.

Carbonate apatite (CO3Ap) is a bioceramic material with excellent properties for bone and dentin regeneration. To enhance its mechanical strength and bioactivity, silica calcium phosphate composites (Si-CaP) and calcium hydroxide (Ca(OH)2) were added to CO3Ap cement. The aim of this study was to investigate the effect of Si-CaP and Ca(OH)2 on the mechanical properties in terms of the compressive strength and biological characteristics of CO3Ap cement, specifically the formation of an apatite layer and the exchange of Ca, P, and Si elements. Five groups were prepared by mixing CO3Ap powder consisting of dicalcium phosphate anhydrous and vaterite powder added by varying ratios of Si-CaP and Ca(OH)2 and 0.2 mol/L Na2HPO4 as a liquid. All groups underwent compressive strength testing, and the group with the highest strength was evaluated for bioactivity by soaking it in simulated body fluid (SBF) for one, seven, 14, and 21 days. The group that added 3% Si-CaP and 7% Ca(OH)2 had the highest compressive strength among the groups. SEM analysis revealed the formation of needle-like apatite crystals from the first day of SBF soaking, and EDS analysis indicated an increase in Ca, P, and Si elements. XRD and FTIR analyses confirmed the presence of apatite. This combination of additives improved the compressive strength and showed the good bioactivity performance of CO3Ap cement, making it a potential biomaterial for bone and dental engineering applications.

Preclinical evaluation of the effect of periodontal regeneration by carbonate apatite in a canine one-wall intrabony defect model.

This study aimed to histologically compare periodontal regeneration of one-wall intrabony defects treated with open flap debridement, β-tricalcium phosphate (β-TCP), and carbonate apatite (CO3Ap) in dogs. The mandibular third premolars of four beagle dogs were extracted. Twelve weeks after the extraction, a one-wall bone defect of 4mm×5mm (mesio-distal width×depth) was created on the distal side of the mandibular second premolar and mesial side of the fourth premolar. Each defect was randomly allocated to open flap debridement (control group), periodontal regeneration utilizing β-TCP, or CO3Ap. Eight weeks after the surgery, histologic and histometric analyses were performed. No ankylosis, infection, or acute inflammation was observed at any of the experimental sites. Newly formed bone and cementum were observed in all experimental groups. The mineral apposition rate of the alveolar bone crest was higher in the CO3Ap group than in the control and β-TCP groups. The ratio of the new bone area was significantly higher in the CO3Ap group than in the control group (P<0.05). The bone contact percentage of the residual granules was significantly higher in the CO3Ap group than in the β-TCP group (P<0.05). Although this study has limitations, the findings revealed the safety and efficacy of CO3Ap for periodontal regeneration in one-wall intrabony defects in dogs, and CO3Ap has a better ability to integrate with bone than β-TCP.

Elemental concentration in renal stones by wavelength dispersive X‐ray fluorescence spectrometry

AbstractRenal stone formation inside the kidney is one of the major causes of renal failure all over the world. To create preventative measures, it is crucial to examine renal stone's composition and identify the minerals that are responsible for their pathogenesis. Various concerns regarding the pathophysiology of renal stones remain unresolved and have been put forward. However, till date, the complete information is still unclear. In recent years, spectroscopic studies have gained much attention in identifying the chemical compositions that lead to the formation and growth of renal stones. This work employed wavelength‐dispersive X‐ray fluorescence (WDXRF) and Fourier transform infrared (FTIR) spectroscopy to study renal stones. WDXRF results of renal stone samples give the presence of numerous heavy and trace elements. Different elemental constituents like zinc (Zn), copper (Cu), iron (Fe), molybdenum (Mo), nickel (Ni), strontium (Sr), chromium (Cr), zirconium (Zr), palladium (Pd), bromine (Br), ruthenium (Ru), lead (Pb), and arsenic (As) were detected and quantified in the renal stones. Vibrational spectroscopic studies were carried out to know the chemical compositions of renal stones such as calcium oxalate monohydrate (COM), uric acid (UA), and carbonate apatite (CA). Quantitative results of WDXRF have been compared with the results from atomic absorption spectroscopy (AAS) of these stone samples. The available clinical details of the patients were correlated with the spectroscopic results obtained using WDXRF and FTIR spectroscopy.

Effect of L-Glutamic Acid on the Composition and Morphology of Nanostructured Calcium Phosphate as Biomaterial.

Calcium phosphate (CaP) with several chemical compositions and morphologies was prepared by precipitation using aqueous solutions of L-Glutamic acid (H2G) and calcium hydroxide, both mixed together with an aqueous solution (0.15 M) of phosphoric acid. Plate-shaped dicalcium phosphate dihydrate (brushite) particles were obtained and identified at a lower concentration of the solution of the reactants. The Ca/P ratio deduced by EDS was ~1, as expected. The nanoscale dimension of carbonate apatite and amorphous calcium phosphate, with variable Ca/P ratios, were revealed by X-ray diffraction (XRD) and scanning electron microscopy and energy dispersive X-ray spectroscopy analysis (SEM-EDS). They were characterized in medium and high concentrations of calcium hydroxide (0.15 M and 0.20 M). The equilibria involved in all the reactions in aqueous solution were determined. The thermodynamic calculations showed a decrease in the amount of chelate complexes with an increase in pH, being the opposite of [CaPO4-] and [CaHG+]. This fluctuation showed an evident influence on the morphology and polymorphism of CaP particles obtained under the present experimental conditions, with potential use as a biomaterial.

Comparison of bioresorbable bone substitutes, carbonate apatite and β‐tricalcium phosphate, for alveolar bone augmentation with simultaneous implant placement

AbstractAimThis study histologically compared two bioresorbable bone substitutes with different composition, carbonate apatite (CO3Ap) and beta‐tricalcium phosphate (β‐TCP), through alveolar bone augmentation with simultaneous titanium implant placement in beagle dogs.MethodsBone defects (length 7 mm, width 2 mm, and depth 6 mm) were created bilaterally at mandibular premolar sites and augmented with either CO3Ap or β‐TCP granules after titanium implant installation. The specimens with the surrounding tissue were harvested from the mandible at 4, 12, and 24 weeks postoperatively, and histological evaluation was performed.ResultsMost β‐TCP granules dissolved in early stages postoperatively, resulting in a lower volume of alveolar bone surrounding the titanium implant. By contrast, in the case of CO3Ap group, the alveolar ridge was reconstructed without reducing the alveolar bone height, and almost all implant threads were covered with new bone by at least 12 weeks postoperatively. Quantitatively, the CO3Ap group showed a significantly higher percentage of new bone formation in the alveolar ridge portion at all follow‐ups. Additionally, it demonstrated a significantly higher bone‐to‐implant contact ratio than that of the β‐TCP group at 12 and 24 weeks after implantation (70.8 ± 5.6% vs. 29.3 ± 16.4% and 54.8 ± 6.9% vs. 41.8 ± 2.2%, respectively).ConclusionIn conclusion, based on the superior outcomes noted in this study, CO3Ap is useful for clinical use in alveolar bone augmentation with simultaneous implant placement.

Retarding breast tumor growth with nanoparticle-facilitated intravenous delivery of BRCA1 and BRCA2 tumor suppressor genes

Gene augmentation therapy entails replacement of the abnormal tumor suppressor genes in cancer cells. In this study, we performed gene augmentation for BRCA1/2 tumor suppressors in order to retard tumor development in breast cancer mouse model. We formulated inorganic carbonate apatite (CA) nanoparticles (NPs) to carry and deliver the purified BRCA1/2 gene- bearing plasmid DNA both in vitro and in vivo. The outcome of BRCA1/2 plasmid-loaded NPs delivery on cellular viability of three breast cancer cell lines such as MCF-7, MDA-MB-231 and 4T1 were evaluated by MTT assay. The result in MCF-7 cell line exhibited that transfection of BRCA 1/2 plasmids with CA NPs significantly reduced cancer cell growth in comparison to control group. Moreover, we noticed a likely pattern of cellular cytotoxicity in 4T1 murine cancer cell line. Following transfection with BRCA1 plasmid-loaded NPs, and Western blot analysis, a notable reduction in the phospho-MAPK protein of MAPK signaling pathway was detected, revealing reduced growth signal. Furthermore, in vivo study in 4T1 induced breast cancer mouse model showed that the tumor growth rate and final volume were decreased significantly in the mouse group treated intravenously with BRCA1 + NPs and BRCA2 + NPs formulations. Our results established that BRCA1/2 plasmids incorporated into CA NPs mitigated breast tumor growth, signifying their application in the therapy for breast cancer.

Periodontal Tissue Regeneration by Transplantation of Autologous Adipose Tissue-Derived Multi-Lineage Progenitor Cells With Carbonate Apatite

We have developed an autologous transplantation method using adipose tissue-derived multi-lineage progenitor cells (ADMPCs) as a method of periodontal tissue regeneration that can be adapted to severe periodontal disease. Our previous clinical study confirmed the safety of autologous transplantation of ADMPCs and demonstrated its usefulness in the treatment of severe periodontal disease. However, in the same clinical study, we found that the fibrin gel used as the scaffold material might have caused gingival recession and impaired tissue regeneration in some patients. Carbonate apatite has a high space-making capacity and has been approved in Japan for periodontal tissue regeneration. In this study, we selected carbonate apatite as a candidate scaffold material for ADMPCs and conducted an in vitro examination of its effect on the cellular function of ADMPCs. We further performed autologous ADMPC transplantation with carbonate apatite as the scaffold material in a model of one-wall bone defects in beagles and then analyzed the effect on periodontal tissue regeneration. The findings showed that carbonate apatite did not affect the cell morphology of ADMPCs and that it promoted proliferation. Moreover, no effect on secretor factor transcription was found. The results of the in vivo analysis confirmed the space-making capacity of carbonate apatite, and the acquisition of significant new attachment was observed in the group involving ADMPC transplantation with carbonate apatite compared with the group involving carbonate apatite application alone. Our results demonstrate the usefulness of carbonate apatite as a scaffold material for ADMPC transplantation.

Gear-shaped carbonate apatite granules with a hexagonal macropore for rapid bone regeneration

Synthetic bone grafts are in high demand owing to increased age-related bone disorders in the global aging population. Here, we report fabrication of gear-shaped granules (G-GRNs) for rapid bone healing. G-GRNs possessed six protrusions and a hexagonal macropore in the granular center. These were composed of carbonate apatite, i.e., bone mineral, microspheres with ∼1-μm micropores in the spaces between the microspheres. G-GRNs formed new bone and blood vessels (both on the granular surface and within the macropores) 4 weeks after implantation in the rabbit femur defects. The formed bone structure was similar to that of cancellous bone. The bone percentage in the defect recovered to that in a normal rabbit femur at week-4 post-implantation, and the bone percentage remained constant for the following 8 weeks. Throughout the entire period, the bone percentage in the G-GRN-implanted group was ∼10% higher than that of the group implanted with conventional carbonate apatite granules. Furthermore, a portion of the G-GRNs resorbed at week-4, and resorption continued for the following 8 weeks. Thus, G-GRNs are involved in bone remodeling and are gradually replaced with new bone while maintaining a suitable bone level. These findings provide a basis for the design and fabrication of synthetic bone grafts for achieving rapid bone regeneration.

Novel Synthetic Carbonate Apatite as a Bone Substitute in Implant Treatments: Case Reports.

Bone graft materials are often used in implant treatment to optimize functional and esthetic outcomes. The requirements for bone grafting materials are the ability to maintain space for bone regeneration to occur and the capability of being resorbed by osteoclasts and replaced with new bone tissue occurring in passive chemolysis and bone remodeling. Carbonate apatite (CO3Ap) granules (Cytrans Granules, GC) are a chemically synthetic bone graft material similar to autogenous bone minerals and more biocompatible than allografts and xenografts. The aim of this report is to evaluate the efficacy of CO3Ap granules in implant treatments when used alone or in combination with autogenous bone. The clinical findings and the radiographic and histologic assessments in three cases of immediate implant placement and lateral and vertical guided bone regeneration are reported. Despite the short-term follow-ups, histologic findings showed that CO3Ap granules were efficiently resorbed and replaced bone in clinical use. Furthermore, the clinical findings showed that CO3Ap granules maintained their morphology around the implant. This limited short-term case report suggests that this bone substitute is effective. However, further clinical studies and long-term reports of this new biomaterial are needed.

Tetrasodium EDTA for the prevention of urinary catheter infections and blockages.

Long-term catheterised individuals are at significant risk of developing catheter-associated urinary tract infections (CAUTIs), with up to 50% of patients experiencing recurrent episodes of catheter encrustation and blockage. Catheter blockage is a result of accumulation of carbonate apatite and struvite formed upon precipitation of ions within urine due to an infection-induced rise in pH. The aim of this study was to investigate the antimicrobial and anti-encrustation activities of tetrasodium ethylenediaminetetraacetic acid (tEDTA) to evaluate its potential efficacy in preventing CAUTIs and catheter blockages. The antimicrobial activity of tEDTA against uropathogens was assessed using time kill assays performed in artificial urine (AU). Crystallisation studies and in vitro bladder model assays were conducted to investigate the effect of tEDTA on struvite crystallisation and catheter blockage. tEDTA displayed bacteriostatic activity against Proteus mirabilis and prevented precipitation of ions in the AU. Crystallisation studies confirmed tEDTA inhibits struvite nucleation and growth via Mg2+ chelation with 7.63 mM tEDTA, equimolar to the concentration of divalent cations in AU, preventing the formation of crystalline deposits and blockage of Foley catheters for ≥168 h. The promising chelating abilities of low tEDTA concentrations could be exploited to inhibit encrustation and blockage of indwelling catheters. The fundamental research presented will inform our future development of an effective tEDTA-eluting catheter coating aimed at preventing catheter encrustation.

Reconstruction of rabbit mandibular bone defects using carbonate apatite honeycomb blocks with an interconnected porous structure

Carbonate apatite (CO3Ap) granules are useful as a bone substitute because they can be remodeled to new natural bone in a manner that conforms to the bone remodeling process. However, reconstructing large bone defects using CO3Ap granules is difficult because of their granular shape. Therefore, we fabricated CO3Ap honeycomb blocks (HCBs) with continuous unidirectional pores. We aimed to elucidate the tissue response and availability of CO3Ap HCBs in the reconstruction of rabbit mandibular bone defects after marginal mandibulectomy. The percentages of the remaining CO3Ap area and calcified bone area (newly formed bone) were estimated from the histological images. CO3Ap area was 49.1 ± 4.9%, 30.3 ± 3.5%, and 25.5 ± 8.8%, whereas newly formed bone area was 3.0 ± 0.6%, 24.3 ± 3.3%, and 34.7 ± 4.8% at 4, 8, and 12 weeks, respectively, after implantation. Thus, CO3Ap HCBs were gradually resorbed and replaced by new bone. The newly formed bone penetrated most of the pores in the CO3Ap HCBs at 12 weeks after implantation. By contrast, the granulation tissue scarcely invaded the CO3Ap HCBs. Some osteoclasts invaded the wall of CO3Ap HCBs, making resorption pits. Furthermore, many osteoblasts were found on the newly formed bone, indicating ongoing bone remodeling. Blood vessels were also formed inside most of the pores in the CO3Ap HCBs. These findings suggest that CO3Ap HCBs have good osteoconductivity and can be used for the reconstruction of large mandibular bone defects.Graphical The CO3Ap HCB were gradually resorbed and replaced by newly formed bone.

Endowing osseointegration ability to bioinert alumina by carbonate apatite coating

The main reason for revision arthroplasty with an alumina-based prosthesis is aseptic loosening of the prosthesis. To prevent loosening of the prosthesis, endowing bioinert alumina with osteogenic ability is deemed an effective approach. Hence, we developed an alumina substrate with carbonate apatite and evaluated its effectiveness for early binding to the bone. Alumina substrates were coated with carbonate apatite using the following procedures: (1) etching the alumina substrate by alkaline hydrothermal treatment; (2) calcium carbonate coating of the etched alumina substrate; and (3) composition conversion of calcium carbonate coating into carbonate apatite by phosphatization. The tensile bond strength of carbonate apatite coating to alumina substrate was 17.6 MPa, which satisfied the criteria defined by the International Organization for Standardization. Contrary to the results of etched alumina substrates, the carbonate apatite-coated alumina substrates promoted the proliferation and osteogenic differentiation of mesenchymal stem cells and induced mineralization. Furthermore, the carbonate apatite-coated alumina substrates strongly adhered to the rabbit tibia 4 weeks after implantation compared to the etched alumina substrates. The contact area and adhesion strength of carbonate apatite-coated alumina substrates to bone were approximately 19- and 6-fold higher than those of etched alumina substrates, respectively. Thus, carbonate apatite coating may contribute to preventing the loosening of alumina prostheses.

Formation and composition of crust in the nephrostomy tube of patients undergoing percutaneous nephrostomy

To investigate the formation and composition of crust in the nephrostomy tube (NT) of patients undergoing percutaneous nephrostomy (PCN). Consecutive patients undergoing PCN for the treatment of obstructive nephropathy who then underwent NT exchange between January 2020 and May 2022 were included in the study. The composition of crust in NTs was analyzed using infrared spectrum automatic analysis system. A total of 46 NTs were collected from 46 consecutive patients (19 men, 27 women; mean age, 68.5 ± 13.4 years) who underwent PCN. The median indwelling time of NTs was 96 days (Q1, 90 days; Q3, 140 days). Among the 46 NTs, 20 (43.5%) were positive for the presence of crust. The mean indwelling time was significantly longer in NTs positive for crust than in those negative for crust (169.7 ± 55.7 days vs 86.5 ± 15.0 days; P < .01). In the NTs positive for crust, the crust was composed of mixed components (apatite carbonate and magnesium ammonium phosphate hexahydrate, n = 7; apatite carbonate and calcium oxalate monohydrate, n = 4) in 11 NTs and a single component (apatite carbonate, n = 5; anhydrous uric acid, n = 2; calcium oxalate monohydrate, n = 2) in 9 NTs. When the NT indwelling time was longer than 3 months, the incidence of crust formation in the NT was significantly increased. Crust was most commonly composed of mixed components. In light of these findings, we suggest that NTs should be exchanged every 3 to 4 months to prevent the formation of crust and thus prevent obstruction of the NT.

РАСПРОСТРАНЕНИЕ ТИПОВ МОЧЕВЫХ КАМНЕЙ У ДЕТЕЙ И ПОДРОСТКОВ В РОССИЙСКОЙ ФЕДЕРАЦИИ

The incidence of urolithiasis among children is rapidly increasing worldwide. Children with nephrolithiasis are at high risk of developing kidney stone recurrence. The prevalence of various types of urinary stones can vary significantly in different regions of the world. The knowledge of the composition of urinary stones is the most important stage in the examination of a patient with urolithiasis to assess changes in metabolism and prescribe effective metaphylactic treatment. The purpose of the study was to assess the prevalence of urinary stone types in Russia among children and adolescents under 25 years old. Research materials and methods: data on the composition of the urinary stones are presented by “INVITRO,” LLC in anonymized form for the period 2018 to 2021. All urinary stone analyzes were performed in different Russia regions using infrared spectroscopy and/or X-ray diffraction. Results: the prevalence of one-, two-, three- and more multicomponent urinary stones among the Russian children's population was assessed. The research studied the chemical composition of 538 urinary stones, of which single-component composition was found in only 28 cases (5.2%), two-component stones - in 298 studies (55.4%), and three- or more-component stones - in 212 (39.4 %) cases. Single-component calcium-containing stones were detected in 50% of girls and 80% of boys (p&lt;0.001). They are predominantly represented by calcium oxalate monohydrate (COM) both among girls and boys. Attention is drawn to the high frequency of detection of infectious stones from struvite and ammonium urate in girls (100%). Among the two-component stones, the most common stones were those from COM + COD (n=187), which were detected in approximately equal proportions among boys and girls. Stones from COM + struvite and carbonate apatite + struvite were statistically significantly more common in girls (p&lt;0.001). The most common multicomponent stone is a mixture of COM + COD and carbonate apatite (88.2%, n=187), almost evenly distributed among boys and girls. The second most common were stones from a mixture of COM + COD and struvite, statistically significantly more common in girls - 61.9% versus 38.1% in boys (p&lt;0.001). Conclusion: the urinary stone composition analysis has a significant role in the assessment of metabolic disorders and determination of the mechanism of initiation of stone formation. In accordance with the clinical guidelines of the Russian Society of Urology for urolithiasis, approved by the Russian Healthcare Ministry, the study of urinary stones is mandatory. It is necessary to increase the volume of studies of urinary stone composition in children from all the Russia regions.