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International Journal of Molecular... Aug 2021Kidney stone disease is one of the oldest diseases known to medicine; however, the mechanisms of stone formation and development remain largely unclear. Over the past... (Review)
Review
Kidney stone disease is one of the oldest diseases known to medicine; however, the mechanisms of stone formation and development remain largely unclear. Over the past decades, a variety of theories and strategies have been developed and utilized in the surgical management of kidney stones, as a result of recent technological advances. Observations from the authors and other research groups suggest that there are five entirely different main mechanisms for kidney stone formation. Urinary supersaturation and crystallization are the driving force for intrarenal crystal precipitation. Randall's plaques are recognized as the origin of calcium oxalate stone formation. Sex hormones may be key players in the development of nephrolithiasis and may thus be potential targets for new drugs to suppress kidney stone formation. The microbiome, including urease‑producing bacteria, nanobacteria and intestinal microbiota, is likely to have a profound effect on urological health, both positive and negative, owing to its metabolic output and other contributions. Lastly, the immune response, and particularly macrophage differentiation, play crucial roles in renal calcium oxalate crystal formation. In the present study, the current knowledge for each of these five aspects of kidney stone formation is reviewed. This knowledge may be used to explore novel research opportunities and improve the understanding of the initiation and development of kidney stones for urologists, nephrologists and primary care.
Topics: Apatites; Calcinosis; Calcium Oxalate; Calcium Phosphates; Gastrointestinal Microbiome; Humans; Kidney; Kidney Calculi; Struvite; Uric Acid; Urolithiasis
PubMed: 34132361
DOI: 10.3892/ijmm.2021.4982 -
Nature Reviews. Nephrology Sep 2016The most common presentation of nephrolithiasis is idiopathic calcium stones in patients without systemic disease. Most stones are primarily composed of calcium oxalate... (Review)
Review
The most common presentation of nephrolithiasis is idiopathic calcium stones in patients without systemic disease. Most stones are primarily composed of calcium oxalate and form on a base of interstitial apatite deposits, known as Randall's plaque. By contrast some stones are composed largely of calcium phosphate, as either hydroxyapatite or brushite (calcium monohydrogen phosphate), and are usually accompanied by deposits of calcium phosphate in the Bellini ducts. These deposits result in local tissue damage and might serve as a site of mineral overgrowth. Stone formation is driven by supersaturation of urine with calcium oxalate and brushite. The level of supersaturation is related to fluid intake as well as to the levels of urinary citrate and calcium. Risk of stone formation is increased when urine citrate excretion is <400 mg per day, and treatment with potassium citrate has been used to prevent stones. Urine calcium levels >200 mg per day also increase stone risk and often result in negative calcium balance. Reduced renal calcium reabsorption has a role in idiopathic hypercalciuria. Low sodium diets and thiazide-type diuretics lower urine calcium levels and potentially reduce the risk of stone recurrence and bone disease.
Topics: Apatites; Calcium; Humans; Hypercalciuria; Kidney Calculi
PubMed: 27452364
DOI: 10.1038/nrneph.2016.101 -
Joint Bone Spine Dec 2018Calcific tendonitis of the rotator cuff is due to apatite deposits in the shoulder tendons. Patients affected by calcific tendonitis have chronic shoulder pain and... (Review)
Review
Calcific tendonitis of the rotator cuff is due to apatite deposits in the shoulder tendons. Patients affected by calcific tendonitis have chronic shoulder pain and disability. Although the disease is frequent, about 10 to 42% of painful shoulders, mechanisms leading to this pathological mineralization are still largely unknown. Research reported in the 1990s suggested that the formation of calcific deposits is linked to cells looking like chondrocytes identified around calcium deposits within a fibrocartilage area. They were considered to be derived from tenocytes but more recently, tendon stem cells, able to differentiate into chondrocytes, were isolated. The pro-mineralizing properties of these chondrocytes-like cells, especially the role of alkaline phosphatase, are not currently clarified. The calcium deposits contain poorly crystalline carbonated apatite associated with protein. Among these proteins, only osteopontin has been consistently identified as a potential regulating factor. During the disease, spontaneous resorption can occur with migration of apatite crystals into the subacromial bursa causing severe pain and restriction of movement. In in vivo and in vitro experiments, apatite crystals were able to induce an influx of leucocytes and a release of IL-1β and IL-18 through the activation of the NLRP3 inflammasome. However, mechanisms leading to spontaneous resolution of this inflammation and disappearance of the calcification still need to be elucidated.
Topics: Apatites; Calcinosis; Humans; Rotator Cuff; Shoulder Joint; Tendinopathy; Tendons
PubMed: 29195923
DOI: 10.1016/j.jbspin.2017.10.004 -
International Journal of Molecular... Nov 2022The aim of the study was to analyze the chemical−physical properties and bioactivity (apatite-forming ability) of three recently introduced premixed bioceramic root...
The aim of the study was to analyze the chemical−physical properties and bioactivity (apatite-forming ability) of three recently introduced premixed bioceramic root canal sealers containing varied amounts of different calcium silicates (CaSi): a dicalcium and tricalcium silicate (1−10% and 20−30%)-containing sealer with zirconium dioxide and tricalcium aluminate (CERASEAL); a tricalcium silicate (5−15%)-containing sealer with zirconium dioxide, dimethyl sulfoxide and lithium carbonate (AH PLUS BIOCERAMIC) and a dicalcium and tricalcium silicate (10% and 25%)-containing sealer with calcium aluminate, tricalcium aluminate and tantalite (NEOSEALER FLO). An epoxy resin-based sealer (AH PLUS) was used as control. The initial and final setting times, radiopacity, flowability, film thickness, open pore volume, water absorption, solubility, calcium release and alkalizing activity were tested. The nucleation of calcium phosphates and/or apatite after 28 days aging in Hanks balanced salt solution (HBSS) was evaluated by ESEM-EDX, vibrational IR and micro-Raman spectroscopy. The analyses showed for NeoSealer Flo and AH Plus the longest final setting times (1344 ± 60 and 1300 ± 60 min, respectively), while shorter times for AH Plus Bioceramic and Ceraseal (660 ± 60 and 720 ± 60 min, respectively). Radiopacity, flowability and film thickness complied with ISO 6876/12 for all tested materials. A significantly higher open pore volume was observed for NeoSealer Flo, AH Plus Bioceramic and Ceraseal when compared to AH Plus (p < 0.05), significantly higher values were observed for NeoSealer Flo and AH Plus Bioceramic (p < 0.05). Ceraseal and AH Plus revealed the lowest solubility. All CaSi-containing sealers released calcium and alkalized the soaking water. After 28 days immersion in HBSS, ESEM-EDX analyses revealed the formation of a mineral layer that covered the surface of all bioceramic sealers, with a lower detection of radiopacifiers (Zirconium for Ceraseal and AH Plus Bioceramic, Tantalum for NeoSealer Flo) and an increase in calcium, phosphorous and carbon. The calcium phosphate (CaP) layer was more evident on NeoSealer Flo and AH Plus Bioceramic. IR and micro-Raman revealed the formation of calcium carbonate on the surface of all set materials. A thin layer of a CaP phase was detected only on AH Plus Bioceramic and NeoSealer Flo. Ceraseal did not show CaP deposit despite its highest calcium release among all the tested CaSi-containing sealers. In conclusion, CaSi-containing sealers met the required chemical and physical standards and released biologically relevant ions. Slight/limited apatite nucleation was observed in relation to the high carbonation processes.
Topics: Root Canal Filling Materials; Calcium; Dental Pulp Cavity; Silicates; Water; Apatites
PubMed: 36430393
DOI: 10.3390/ijms232213914 -
Canadian Journal of Dental Hygiene :... Oct 2021Dental caries is still one of the most prevalent diseases worldwide. Research has shown that fluoride has a role in caries prevention. For many reasons there are... (Meta-Analysis)
Meta-Analysis
UNLABELLED
Dental caries is still one of the most prevalent diseases worldwide. Research has shown that fluoride has a role in caries prevention. For many reasons there are concerns about young children using fluoride-containing oral care products. Consequently, there is a need to identify effective fluoride-free products. A large body of literature now exists on the use of biomimetic hydroxyapatite (HAP) as an active ingredient in oral care products to combat caries.
AIM
To conduct a systematic review of the clinical evidence of the effects of HAP-based fluoride-free oral care products in caries reduction and conduct a meta-analysis of available randomized clinical trials (RCTs).
METHODS
Using the PICO question "In individuals of all ages (P), do fluoride-free oral care products containing HAP as the anti-caries agent (I), compared to products with fluoride or without caries control products (C), reduce the risk of dental caries (O)?" Ovid MEDLINE (PubMed), Scopus, EMBASE, and Web of Science databases were searched using the following keywords: apatite, hydroxyapatite, caries, dental decay, dentin(e), enamel, toothpaste, dentifrice, mouthwash, gels, biofilm, (dental) plaque, ero(de, ded, sion), (de, re)mineral(ise, ized, ised, ization, isation). Reviews, tooth whitening, tooth sensitivity, and in vitro studies were excluded. PRISMA was used for the search and GRADE was used to assess quality. Clinical trials were subjected to the Cochrane Risk of Bias assessment followed by meta-analysis.
RESULTS
291 studies were retrieved; 22 were suitable for systematic review, 5 were clinical caries trials and 4 were RCTs. A meta-analysis of 3 RCTs was possible showing HAP provided 17% protection against caries. The other 17 trials had simpler proxy outcomes for anticaries effects. Some trials showed non-inferior performance of HAP products compared to those with fluoride.
CONCLUSION
There is good evidence that hydroxyapatite in oral care products in the absence of fluoride effectively reduces caries.
Topics: Biomimetics; Child; Child, Preschool; Dental Caries; Dental Caries Susceptibility; Durapatite; Fluorides; Humans
PubMed: 34925515
DOI: No ID Found -
International Journal of Molecular... Aug 2022Apatites are one of the most intensively studied materials for possible biomedical applications. New perspectives of possible application of apatites correspond with the...
Apatites are one of the most intensively studied materials for possible biomedical applications. New perspectives of possible application of apatites correspond with the development of nanomaterials and nanocompounds. Here, an effort to systematize different kinds of human bioapatites forming bones, dentin, and enamel was undertaken. The precursors of bioapatites and hydroxyapatite were also considered. The rigorous consideration of compositions and stoichiometry of bioapatites allowed us to establish an order in their mutual sequence. The chemical reactions describing potential transformations of biomaterials from octacalcium phosphate into hydroxyapatite via all intermediate stages were postulated. Regardless of whether the reactions occur in reality, all apatite biomaterials behave as if they participate in them. To conserve the charge, additional free charges were introduced, with an assumed meaning to be joined with the defects. The distribution of defects was coupled with the values of crystallographic parameters "" and "". The energetic balances of bioapatite transformations were calculated. The apatite biomaterials are surprisingly regular structures with non-integer stoichiometric coefficients. The results presented here will be helpful for the further design and development of nanomaterials.
Topics: Apatites; Biocompatible Materials; Bone and Bones; Crystallography; Durapatite; Humans
PubMed: 36076932
DOI: 10.3390/ijms23179537 -
Journal of Dental Research Jun 2015Enamel is unique. It is the only epithelial-derived mineralized tissue in mammals and has a distinct micro- and nanostructure with nanofibrous apatite crystals as... (Review)
Review
Enamel is unique. It is the only epithelial-derived mineralized tissue in mammals and has a distinct micro- and nanostructure with nanofibrous apatite crystals as building blocks. It is synthesized by a highly specialized cell, the ameloblast, which secretes matrix proteins with little homology to any other known amino acid sequence, but which is composed of a primary structure that makes it competent to self-assemble and control apatite crystal growth at the nanometer scale. The end-product of ameloblast activity is a marvel of structural engineering: a material optimized to provide the tooth with maximum biting force, withstanding millions of cycles of loads without catastrophic failure, while also protecting the dental pulp from bacterial attack. This review attempts to bring into context the mechanical behavior of enamel with the developmental process of amelogenesis and structural development, since they are linked to tissue function, and the importance of controlling calcium phosphate mineralization at the nanometer scale. The origins of apatite nanofibers, the development of a stiffness gradient, and the biological processes responsible for the synthesis of a hard and fracture-resistant dental tissue are discussed with reference to the evolution of enamel from a fibrous composite to a complex, tough, and damage-tolerant coating on dentin.
Topics: Ameloblasts; Amelogenesis; Apatites; Biomechanical Phenomena; Calcium Phosphates; Crystallization; Dental Enamel; Dental Enamel Proteins; Humans; Nanofibers; Tooth Calcification
PubMed: 25800708
DOI: 10.1177/0022034515577963 -
Journal of Nanobiotechnology Jan 2019Dental caries is a recognized worldwide public health problem. Despite being one of the most effective strategies against dental caries, the excessive use of fluorine... (Comparative Study)
Comparative Study
BACKGROUND
Dental caries is a recognized worldwide public health problem. Despite being one of the most effective strategies against dental caries, the excessive use of fluorine may result in a potential risk of developing dental fluorosis especially in children under age of six. The purpose of this work is to analyze a fluorine-free toothpaste containing Biomimetic Hydroxyapatite to assess enamel re-mineralizing and repairing properties.
RESULTS
The study was performed in vitro and in vivo, comparing the hydroxyapatite toothpaste with two others toothpaste containing different fluorine concentrations. The coating effect of the micro-structured Hydroxyapatite nanoparticles reintegrates the enamel with a biomimetic film reproducing the structure and the morphology of the biologic Hydroxyapatite of the enamel. As demonstrated, the coating is due to the deposit of a new layer of apatite, which presents fewer particles than the natural enamel, not based on the chemical-physical changes occurring in fluorinated toothpastes. Moreover, it shows resistance to brushing as a consequence of chemical bonds between the synthetic and natural crystals of the enamel.
CONCLUSIONS
The use of Biomimetic Hydroxyapatite toothpastes has proven to be a valuable prevention measure against dental caries in primary dentition since it prevents the risk of fluorosis.
Topics: Biomimetics; Child; Coated Materials, Biocompatible; Dental Caries; Dental Enamel; Durapatite; Fluorides; Humans; Streptococcus mutans; Tooth Remineralization; Tooth, Deciduous; Toothpastes
PubMed: 30683113
DOI: 10.1186/s12951-019-0454-6 -
Atencion Primaria 2019
Topics: Adult; Apatites; Female; Humans; Kidney Calculi; Low Back Pain; Proteus mirabilis; Struvite; Tomography, X-Ray Computed
PubMed: 30732968
DOI: 10.1016/j.aprim.2018.09.014 -
Dental Materials : Official Publication... Nov 2022The aim of this study was to investigate the degradation of inert glass fillers which are commonly used in conventional resin-based composites to provide radiopacity,...
OBJECTIVES
The aim of this study was to investigate the degradation of inert glass fillers which are commonly used in conventional resin-based composites to provide radiopacity, reduce the polymerization shrinkage and improve the mechanical properties.
METHODS
75 mg of five different glass powders (1 µm) was immersed separately into 50 mL of acetic acid (pH 4) and tris buffer (pH 7.4) for up to 4 weeks. At each time point the glass powder was filtered and dried for characterization using ATR-FTIR and XRD to assess the degradation behavior and crystallization. ICP-OES, ISE and pH measurements were performed on the supernatant solutions to monitor the pH and ion release.
RESULTS
Although FTIR and XRD analysis showed no significant glass degradation or crystallization upon immersion, there was a substantial release of ions from the inert fillers, especially from BABFG and CDL. Barium release for these fillers were 270 and 165 ppm respectively. G018-373 glass presented the lowest ion release followed by GM27884 and BABG. The ion release was more pronounced in acidic conditions compared to neutral conditions apart from the fluoride release.
SIGNIFICANCE
Inert glasses are not as inert as previously thought. This may result in leaching of ions, potentially causing toxicity, reduction in mechanical properties, increased wear and subsequent failure of the composite material. The ions released from the inert glass may interfere with other glass fillers such as bioactive glass fillers, inhibiting degradation of the bioactive glass, beneficial ion release from the bioactive glass, pH neutralization and apatite formation.
Topics: Apatites; Barium; Fluorides; Glass; Materials Testing; Powders; Tromethamine
PubMed: 36154969
DOI: 10.1016/j.dental.2022.09.004