Calcium Phosphate Crystals Research Articles

Influence of Additives on Crystallization of Calcium Phosphates from Prototypes of Blood Plasma

The paper presents the results of studies on the effect of additives on crystallization in solutions simulating the composition of human blood plasma. Synthesis from prototypes of human blood plasma in the presence of organic and inorganic additives was carried out, and it was found that the obtained solid phases consisted of octacalcium phosphate, B-type carbonate hydroxyapatite, and vitlocite. The effect of additives (magnesium ions, alanine, and glycine) on the crystallization of calcium phosphates was studied. It was found that the presence of additives in the model solution reduces the crystallite size and the fraction of carbonate hydroxyapatite in the solid phase. The bioactivity of synthetic samples was studied, and kinetic characteristics were established. A study of thermal transformations.

Phosphate pre-concentration from wastewater by a continuous flow bench-scale forward osmosis membrane: A circular economy approach on nutrient recovery

Phosphate is a vital element necessary for the growth and development of plants, making it a crucial element in agricultural fertilizers. Extracting phosphate from wastewater for recovery aligns with the principles of a circular economy by closing the loop on nutrient cycles. Instead of viewing wastewater as a waste product, treating it as a resource for recovering valuable nutrients like phosphate promotes a more sustainable and efficient use of resources. In this study, the phosphate from synthetic wastewater was pre-concentrated by a continuous flow forward osmosis membrane system to facilitate effective precipitation. The pre-concentration feasibility of forward osmosis was studied by changing the draw concentration, feed concentration, feed pH, and flow rate of the feed solution. With the optimum operational parameters in batch mode such as pH of 7, the draw solute concentration of 0.4 M MgSO4, the feed and draw flowrate of 0.7 L/min and 0.3 L/min, the phosphate concentration was increased from 30 mg/L to 525 mg/L after 60 min, the average osmotic flux and reverse solute flux was 2.7 L/m2/h and 0.43 g/m2/h, respectively. As operated with continuous mode, the final phosphate concentration was increased four times, the average osmotic flux was higher with 8.1 L/m2/h and the reverse solute flux was 0.86 g/m2/h, which could improve the efficiency of calcium phosphate crystallization in precipitation/ crystallization reactors. This integrated system, which includes forward osmosis as a pretreatment method followed by a precipitation process, is technically possible for application on a larger scale as a circular economy approach.

Pseudocalcinosis Tumorale (Teutschlander Disease) in Chronic Hemodialysis Patients

Pseudotumoral calcinosis (CPT) is a condition characterized by the deposition of calcium phosphate crystals in the periarticular tissues, forming large calcified masses. Although the pathophysiology of CPT is not fully understood, an increase in the calcium-phosphate product beyond the precipitation threshold and severe hyperparathyroidism appear to play a significant role. Treatment remains controversial, with surgical excision often recommended. We report a case of CPT in a 74-year-old diabetic patient undergoing chronic hemodialysis who experienced progressively worsening pain in the left hip for six months, along with mobility difficulties. A CT scan revealed a calcified mass on the posterior thigh, likely explaining the electric shock-like pain, as well as compression of the superficial femoral artery causing decubitus pain resembling critical limb ischemia. The biological assessment showed elevated calcium-phosphate levels and hyperparathyroidism. Surgical excision is not indicated due to the mass’s proximity to vascular and nerve structures. This case highlights the diagnostic and therapeutic challenges of CPT, emphasizing the need for iterative angioplasties, considering that this condition is rare in chronic hemodialysis patients with calcified periarticular masses.

Essential oil release from zein particles as modulated by inorganic coating and biopolymeric networking

Zein particles (ZPs) have emerged as a popular delivery carrier for hydrophobic bioactive substances. However, some lipophilic compounds are easily released from ZPs because of the low polarity compatibility between zein and the compounds. The loss of encapsulated substances is particularly evident for citrus essential oil (CEO), an extremely hydrophobic ingredient. The premature release of CEO from ZPs was mitigated by developing a modification approach using ZPs coated with calcium phosphate (CaP) and networked with Ca2+-alginate gel (CaAlg). The approach involved the preparation of ZPs (through the antisolvent addition procedure) in phosphate buffer, and supplementation of the particles consecutively with sodium alginate and Ca2+ ions (as CaCl2). This procedure resulted in retention of up to 28% of CEO within ZPs after the accelerated storage experiment. Under in vitro gastric and intestinal digestion condition, the CaP-coated and CaAlg-networked ZPs had a significantly lower release of CEO compared to their non-coated and non-networked counterparts. The morphology of the particles was investigated by scanning (SEM) and transmission (TEM) electron microscopies, as well as confocal laser scanning microscopy. SEM imaging showed that sodium alginate could facilitate the formation of CaP coating through preventing CaP crystallization. CaP coating also decreased the ZPs fusion/aggregation as evidenced by comparing the ζ-potential and microscopic morphology of the particles. Examination of the infrared spectra of the particles revealed that the formation of CaP coating occurred at Ca2+ ion concentrations ≥ 10 mM.

Morphological study of remineralization of the eroded enamel lesions by tyrosine-rich amelogenin peptide

BackgroundTyrosine-rich amelogenin peptide (TRAP) is the main amelogenin digestion product in the developmental enamel matrix. It has been shown to promote remineralization of demineralized enamel in our previous study. However, direct evidence of the effect of TRAP on the morphology and nanostructure of crystal growth on an enamel surface has not been reported. This study aimed to examine the effect of TRAP on the morphology of calcium phosphate crystals grown on early enamel erosion using a pH-cycling model.MethodsEroded lesions were produced in human premolars by 30-second immersion in 37% phosphoric acid. Forty-five samples of eroded human premolar enamel blocks were selected and randomly divided into 3 groups: deionized water (DDW, negative control); 100 µg/mL TRAP, and 2 ppm sodium fluoride (NaF, positive control group). For 14 days, the specimens were exposed to a pH-cycling model. Using scanning electron microscopy (SEM) and atomic force microscopy (AFM) methods, the surface morphology, calcium-phosphorus ratio, and enamel surface roughness were examined. X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to assess crystal characteristics.ResultsAfter pH-cycling, compared to the two control groups, the surface of the eroded enamel of the peptide TRAP group shows a large number of new, densely arranged rod-like crystals, parallel to each other, regularly arranged, forming an ordered structure, with crystal morphology similar to that of natural enamel. The crystals are mostly hydroxyapatite (HA).ConclusionThis study demonstrates that the peptide TRAP modulates the formation of hydroxyapatite in eroded enamel and that the newly formed crystals resemble natural enamel crystals and promote the remineralization of enamel, providing a promising biomaterial for remineralization treatment of enamel lesions.

Branched Polymeric Prenucleation Assemblies Initiate Calcium Phosphate Precipitation.

The formation of crystalline calcium phosphate (CaP) has recently gained ample attention as it does not follow the classic nucleation-and-growth mechanism of solid formation. Instead, the precipitation mechanisms can involve numerous intermediates, including soluble prenucleation species. However, structural features, stability, and transformation of such solution-state precursors remain largely undisclosed. Herein, we report a detailed and comprehensive characterization of the sequential events involved in calcium phosphate crystallization starting from the very early prenucleation stage. We integrated an extensive set of time-resolved methods, including NMR, turbidimetry, SAXS, cryo-TEM, and calcium-potentiometry to show that CaP nucleation is initiated by the transformation of "branched" polymeric prenucleation assemblies into amorphous calcium phosphate spheres. Such a mineralization process starts with the spontaneous formation of so-called nanometric prenucleation clusters (PNCs) that later assemble into those branched polymeric assemblies without calcium ion uptake from the solution. Importantly, the branched macromolecular species are invisible to many techniques (NMR, turbidity, calcium-potentiometry) but can readily be evidenced by time-resolved SAXS. We find that these polymeric assemblies constitute the origin of amorphous calcium phosphate (ACP) precipitation through an unexpected process: spontaneous dissolution is followed by local densification of 100-200 nm wide domains leading to ACP spheres of similar size. Finally, we demonstrate that the timing of the successive events involved in the CaP mineralization pathway can be kinetically controlled by the Ca2+/Pi molar ratio, such that the lifetime of the soluble transient species can be increased up to hours when decreasing it.

Osteogenic-Like Microenvironment of Renal Interstitium Induced by Osteomodulin Contributes to Randall's Plaque Formation.

Calcium oxalate (CaOx) kidney stones are common and recurrent, lacking pharmacological prevention. Randall's plaques (RPs), calcium deposits in renal papillae, serve as niduses for some CaOx stones. This study exploresthe role of osteogenic-like cells in RP formation resembling ossification. CaP crystals deposit around renal tubules, interstitium, and blood vessels in RP tissues. Human renal interstitial fibroblasts (hRIFs) exhibit the highest osteogenic-like differentiation potential compared to chloride voltage-gated channel Ka positive tubular epithelial cells, aquaporin 2 positive collecting duct cells, and vascular endothelial cells, echoing the upregulated osteogenic markers primarily in hRIFs within RP tissues. Utilizing RNA-seq, osteomodulin (OMD) is found to be upregulated in hRIFs within RP tissues and hRIFs following osteogenic induction. Furthermore, OMD colocalizes with CaP crystals and calcium vesicles within RP tissues. OMD can enhance osteogenic-like differentiation of hRIFs in vitro and in vivo. Additionally, crystal deposits are attenuated in mice with Omd deletion in renal interstitial fibroblasts following CaOx nephrocalcinosis induction. Mechanically, a positive feedback loop of OMD/BMP2/BMPR1A/RUNX2/OMD drives hRIFs to adopt osteogenic-like fates, by which OMD induces osteogenic-like microenvironment of renal interstitium to participate in RP formation. Weidentify OMD upregulation as a pathological feature of RP, paving the way for preventing CaOx stones.

Converging Mechanisms of Vascular and Cartilaginous Calcification.

Physiological calcification occurs in bones and epiphyseal cartilage as they grow, whereas ectopic calcification occurs in blood vessels, cartilage, and soft tissues. Although it was formerly thought to be a passive and degenerative process associated with aging, ectopic calcification has been identified as an active cell-mediated process resembling osteogenesis, and an increasing number of studies have provided evidence for this paradigm shift. A significant association between vascular calcification and cardiovascular risk has been demonstrated by various studies, which have shown that arterial calcification has predictive value for future coronary events. With respect to cartilaginous calcification, calcium phosphate or hydroxyapatite crystals can form asymptomatic deposits in joints or periarticular tissues, contributing to the pathophysiology of osteoarthritis, rheumatoid arthritis, ankylosing spondylitis, tendinitis, and bursitis. The risk factors and sequence of events that initiate ectopic calcification, as well as the mechanisms that prevent the development of this pathology, are still topics of debate. Consequently, in this review, we focus on the nexus of the mechanisms underlying vascular and cartilaginous calcifications, trying to circumscribe the similarities and disparities between them to provide more clarity in this regard.

The influence of strontium doping on the crystal morphology of synthetic calcium phosphates

Calcium phosphate crystals were synthesized via chemical precipitation with strontium (Sr) ionic doping, and starting solutions with at.% Sr 19 % (A), 40 % (B), and 53 % (C) in an acid environment (pH 6.0), resulting in the crystal without Sr with plate morphologies, sample A: Sr ∼7.8 % and Ca ∼92,2 % with plate+petaloid crystals, sample B showed two morphological groups: Sr ∼12,5 % and Ca ∼87,5 % (B1) with plate+petaloid crystals and with Sr ∼32,5 % and Ca ∼67,9 % (B2) with petaloid+pseudo-hexagons crystals, and sample C: Sr ∼48,8 % and Ca ∼51,2 % with higher symmetric hexagonal crystals. The samples were characterized by X-ray diffraction, SEM, and EDS. The calcium phosphate crystallographic phase family (Ca-P) includes brushite (DCPD), monetite (DCPA), and hydroxyapatite (HAP) surrounding the nucleating crystals that had plate, petaloid, and pseudo-hexagonal or hexagonal morphologies. Crystal growth nucleation by Sr inclusion ions induces preferential orientation with overlapping layer plates forming pseudo-hexagonal or hexagonal crystals with high symmetry when there is ion equilibrium between Ca and Sr. This result indicates biomimicry crystals found in nature (abalone gastropod shell), resulting in promising materials for further advances in mechanical properties and performance.

Calcium phosphate controls nucleation and growth of calcium oxalate crystal phases in kidney stones.

Kidney stone disease is a serious disease due to the severe pain it causes, high morbidity, and high recurrence rate. Notably, calcium oxalate stones are the most common type of kidney stone. Calcium oxalate appears in two forms in kidney stones: the stable phase, monohydrate (COM), and the metastable phase, dihydrate (COD). Particularly, COM stones with concentric structures are hard and difficult to treat. However, the factor determining the growth of either COM or COD crystals in the urine, which is supersaturated for both phases, remains unclear. This study shows that calcium phosphate ingredients preferentially induce COM crystal nucleation and growth, by observing and analyzing kidney stones containing both COM and COD crystals. The forms of calcium phosphate are not limited to Randall's plaques (1-2 mm size aggregates, which contain calcium phosphate nanoparticles and proteins, and form in the renal papilla). For example, aggregates of strip-shaped calcium phosphate crystals and fields of dispersed calcium phosphate microcrystals (nano to micrometer order) also promote the growth of concentric COM structures. This suggests that patients who excrete urine with a higher quantity of calcium phosphate crystals may be more prone to forming hard and troublesome COM stones.

Smart gradient coating suitable for bone growth prepared on plasma-electrolytically oxidised Mg and its sequential degradation behaviour

A gradient coating containing collagen and inorganic strontium/calcium phosphate (Sr/CaP) was fabricated on plasma-electrolytically oxidised magnesium via one-step cathodic electrodeposition. First, Sr-doped dicalcium phosphate dihydrate and hydroxyapatite (DCPD and HA) was deposited, followed by a collagen/CaP layer. The morphological evolution, sequential degradation behaviour, and in vitro bio-properties of the coatings were investigated. The incorporation of collagen remarkably refined the morphology of the CaP, and a more aggregated nano-spherical morphology was observed with increasing collagen concentration. Sr could partially replace Ca in the CaP crystals. Collagen combined with CaP formed a relatively stable skeletal frame, which provided sufficient barrier properties and more sites for the re-precipitation of bone tissue, as well as a more promising proliferation and differentiation ability of osteoblasts. A gradient coating that matches the requirements of bone growth at various periods is suggested for implantation.

Bioinspired poly-dopamine/nano-hydroxyapatite: an upgrading biocompatible coat for 3D-printed polylactic acid scaffold for bone regeneration.

Poly-lactic acid (PLA) has been proposed in dentistry for several regenerative procedures owing to its biocompatibility and biodegradability. However, the presence of methyl groups renders PLA hydrophobic, making the surface less ideal for cell attachment, and it does not promote tissue regeneration. Upgrading PLA with inductive biomaterial is a crucial step to increase the bioactivity of the PLA and allow cellular adhesion. Our purpose is to evaluate biocompatibility, bioactivity, cellular adhesion, and mechanical properties of 3D-printed PLA scaffold coated with poly-dopamine (PDA) and nano-hydroxyapatite (n-HA) versus PLA and PLA/n-HA scaffolds. The fused deposition modelling technique was used to print PLA, PLA with embedded n-HA particles, and PLA scaffold coated with PDA/n-HA by immersion. After matrices characterization for their chemical composition and surface properties, testing the compressive strength was pursued using a universal testing machine. The bioactivity of scaffolds was evaluated by monitoring the formation of calcium phosphate compounds after simulated body fluid immersion. The PLA/PDA/n-HA scaffold showed the highest compressive strength which was 29.11 ± 7.58 MPa with enhancing calcium phosphate crystals deposition with a specific calcium polyphosphate phase formed exclusively on PLA/PDA/n-HA. With cell viability assay, the PDA/n-HA-coated matrix was biocompatible with increase in the IC50, reaching ⁓176.8 at 72 without cytotoxic effect on the mesenchymal stem cells, promoting their adhesion and proliferation evaluated by confocal microscopy. The study explored the biocompatibility, bioactivity, and the cell adhesion ability of PDA/n-HA coat on a 3D-printed PLA scaffold that qualifies its use as a promising regenerative material.

Antiurolithiatic activity of Indian medicinal plant: Ocimum kilimandscharicum Gurke (Lamiaceae)

Urolithiasis is the most prevalent condition of the urinary system, characterized by the formation of stones inside the urinary tract. It is urgent to look for a natural urolithiasis therapy due to the serious side effects of conventional medications. Hydro-alcoholic (80% v/v) extract of the aerial parts of Ocimum kilimandscharicum (OK) and its ethyl acetate, chloroform, n-butanol, aqueous, and n-hexane fractions were subjected to in vitro antiurolithiatic screening as well as preliminary screening of phytochemicals. The in vitro antiurolithiatic activity of O. kilimandscharicum was studied using its hydroalcoholic extract (HAEOK). Calcium phosphate test using a colorimetric approach and calcium oxalate assay using a titrimetric model were used to determine the proportion of calcium oxalate crystals that dissolved. Total phenolic content (TPC) and total flavonoid content (TFC) were measured for the extract and fractions of OK. Ethyl acetate fraction (EAFOK) had a greater capacity to suppress crystal formation in both the calcium phosphate and calcium oxalate assays. The percent dissolution of calcium oxalate by HAEOK and EAFOK (31.48 ± 0.920% and 39.21 ± 0.903%) and calcium phosphate crystals by HAEOK and EAFOK (59.03 ± 0.820% and 66.62 ± 0.468%) was determined, respectively. At p < 0.05 and p < 0.01, differences between the results were regarded as significant. Cystone was employed as a standard drug. This study revealed that EAFOK showed significant antiurolithiatic activity. The antiurolithiatic activity of the extract/fraction was attributed to the steroids, triterpenoids, and flavonoid content of OK.

Phosphate Recovery Mechanism from Low P-Containing Wastewaters via CaP Crystallization Using Apatite as Seed: Seed Adsorption, Surface-Induced Crystallization, or Ion Clusters Aggregation?

Low P-containing wastewaters (LPWs) exhibit huge P recovery potential, considering their larger volume. P recovery via CaP crystallization using apatite as seed is documented as being potentially well suited for LPWs. However, its responsible mechanisms remain a subject for debate. Taking hydroxyapatite (HAP) as the seed of LPWs, this paper conducted HAP adsorption/dissolution experiments, titration experiments, and P recovery experiments to distinguish the primary responsible mechanism. Results showed that it was HAP dissolution, not P adsorption, that occurred when the initial P concentration was no higher than 5 mg/L, ruling out adsorption mechanism of P recovery from LPWs using HAP as the seed. Significant OH− consumption and rapid P recovery occurred simultaneously within the first 60 s in titration experiments, suggesting CaP crystallization should be responsible for P recovery. Moreover, the continuous increase in P recovery efficiency with seed dosages observed in P recovery experiments seemed to follow well the mechanism of pre-nucleation ion clusters (PNCs) aggregation. During PNCs aggregation, P aggregates with Ca2+ quickly, generating CaP PNCs; then, CaP PNCs aggregate with seed particles, followed by CaP PNCs fusion, and ultimately transform into fines attached to the seed surface. PNCs’ aggregation mechanism was further supported by a comparison of seed SEM images before and after P recovery, since denser and smaller rod-shaped fines were observed on the seed surface after P recovery. This study suggests that PNCs’ aggregation is the dominant mechanism responsible for the recovery of P from LPWs via CaP crystallization using HAP as the seed.

The Rise in Tubular pH during Hypercalciuria Exacerbates Calcium Stone Formation.

In calcium nephrolithiasis (CaNL), most calcium kidney stones are identified as calcium oxalate (CaOx) with variable amounts of calcium phosphate (CaP), where CaP is found as the core component. The nucleation of CaP could be the first step of CaP+CaOx (mixed) stone formation. High urinary supersaturation of CaP due to hypercalciuria and an elevated urine pH have been described as the two main factors in the nucleation of CaP crystals. Our previous in vivo findings (in mice) show that transient receptor potential canonical type 3 (TRPC3)-mediated Ca2+ entry triggers a transepithelial Ca2+ flux to regulate proximal tubular (PT) luminal [Ca2+], and TRPC3-knockout (KO; -/-) mice exhibited moderate hypercalciuria and microcrystal formation at the loop of Henle (LOH). Therefore, we utilized TRPC3 KO mice and exposed them to both hypercalciuric [2% calcium gluconate (CaG) treatment] and alkalineuric conditions [0.08% acetazolamide (ACZ) treatment] to generate a CaNL phenotype. Our results revealed a significant CaP and mixed crystal formation in those treated KO mice (KOT) compared to their WT counterparts (WTT). Importantly, prolonged exposure to CaG and ACZ resulted in a further increase in crystal size for both treated groups (WTT and KOT), but the KOT mice crystal sizes were markedly larger. Moreover, kidney tissue sections of the KOT mice displayed a greater CaP and mixed microcrystal formation than the kidney sections of the WTT group, specifically in the outer and inner medullary and calyceal region; thus, a higher degree of calcifications and mixed calcium lithiasis in the kidneys of the KOT group was displayed. In our effort to find the Ca2+ signaling pathophysiology of PT cells, we found that PT cells from both treated groups (WTT and KOT) elicited a larger Ca2+ entry compared to the WT counterparts because of significant inhibition by the store-operated Ca2+ entry (SOCE) inhibitor, Pyr6. In the presence of both SOCE (Pyr6) and ROCE (receptor-operated Ca2+ entry) inhibitors (Pyr10), Ca2+ entry by WTT cells was moderately inhibited, suggesting that the Ca2+ and pH levels exerted sensitivity changes in response to ROCE and SOCE. An assessment of the gene expression profiles in the PT cells of WTT and KOT mice revealed a safeguarding effect of TRPC3 against detrimental processes (calcification, fibrosis, inflammation, and apoptosis) in the presence of higher pH and hypercalciuric conditions in mice. Together, these findings show that compromise in both the ROCE and SOCE mechanisms in the absence of TRPC3 under hypercalciuric plus higher tubular pH conditions results in higher CaP and mixed crystal formation and that TRPC3 is protective against those adverse effects.

β,γ-Methylene-ATP and its metabolite medronic acid affect both arterial media calcification and bone mineralization in non-CKD and CKD rats.

Arterial media calcification or pathological deposition of calcium-phosphate crystals in the vessel wall contributes significantly to the high mortality rate observed in patients with CKD. Extracellular nucleotides (ie, ATP or UTP) regulate the arterial calcification process by interacting with (1) purinergic receptors and (2) breakdown via ecto-nucleotidases, such as ectonucleotide pyrophosphatase/phosphodiesterase NPP1 or NPP3, affecting the local levels of calcification inhibitor, pyrophosphate, and stimulator inorganic phosphate (PPi/Pi ratio). Also, it has been shown that ATP analogs (ie, β,γ-methylene-ATP [β,γ-meATP]) inhibit vascular smooth muscle cell calcification in vitro. In the first experiment, daily dosing of β,γ-meATP (2mg/kg) was investigated in rats fed a warfarin diet to trigger the development of non-CKD-related arterial medial calcifications. This study showed that β,γ-meATP significantly lowered the calcium scores in the aorta and peripheral vessels in warfarin-exposed rats. In a second experiment, daily dosing of 4mg/kg β,γ-meATP and its metabolite medronic acid (MDP) was analyzed in rats fed an adenine diet to promote the development of CKD-related arterial medial calcification. Administration of β,γ-meATP and MDP did not significantly decrease aortic calcification scores in this model. Moreover, both compounds induced deleterious effects on physiological bone mineralization, causing an imminent risk for worsening the already compromised bone status in CKD. Due to this, it was not possible to raise the dosage of both compounds to tackle CKD-related arterial calcification. Again, this points out the difficult task of targeting solely ectopic calcifications without negatively affecting physiological bone mineralization. On the other hand, aortic mRNA expression of Enpp1 and Enpp3 was significantly and positively associated with aortic calcification scores, suggesting that normalizing the aortic NPP1/3 activity to control values might be a possible target to treat (CKD-induced) arterial media calcifications.

Stratified control of chemical crystallization in a pellet fluidized bed for pH-Adjusted fluoride and phosphate reduction: An experimental study

Chemical crystallization granulation in a fluidized bed offers an environmentally friendly technology with significant promise for fluoride removal. This study investigates the impact of stratified pH control in a crystallization granulation fluidized bed for the removal of fluoride and phosphate on a pilot scale. The results indicate that using dolomite as a seed crystal, employing sodium dihydrogen phosphate (SDP) and calcium chloride as crystallizing agents, and controlling the molar ratio n(F):n(P):n(Ca) = 1:5:10 with an upflow velocity of 7.52 m/h, effectively removes fluoride and phosphate. Stratified pH control—maintaining weakly acidic conditions (pH = 6–7) at the bottom and weakly alkaline conditions (pH = 7–8) at the top—facilitates the induction of fluoroapatite (FAP) and calcium phosphate crystallization. This approach reduces groundwater fluoride levels from 9.5 mg/L to 0.2–0.6 mg/L and phosphate levels to 0.1–0.2 mg/L. Particle size analysis, scanning electron microscopy–energy-dispersive X-ray spectroscopy, and X-ray diffraction physical characterizations reveal significant differences in crystal morphology between the top and bottom layers, with the lower layer primarily generating high-purity FAP crystals. Further analysis shows that dolomite-induced FAP crystallization offers distinct advantages. SDP not only dissolves on the dolomite surface to provide active sites for crystallization but also, under weakly acidic conditions, renders both dolomite and FAP surfaces negatively charged. This allows for the effective adsorption of PO43−, HPO42−, and F− anions onto the crystal surfaces. This study provides supporting data for the removal of fluoride from groundwater through induced FAP crystallization in a chemical crystallization pellet fluidized bed.

Calcium Pyrophosphate and Basic Calcium Phosphate Crystal Arthritis: 2023 in Review

Calcium-containing crystal deposition diseases are extremely common in rheumatology. However, they are under-explored compared to gout or other inflammatory rheumatic diseases. Major advances have been made in 2023 that will undoubtedly stimulate and facilitate research in the field of calcium pyrophosphate (CPP) deposition disease (CPPD): the ACR/EULAR classification criteria for CPPD and a semi-quantitative OMERACT score for ultrasound assessment of the extent of CPP deposition have been validated and published. A large randomized controlled trial compared the efficacy and safety of colchicine and prednisone in acute CPP arthritis. Preclinical studies have elucidated the pro-inflammatory and anti-catabolic effects of basic calcium phosphate (BCP) crystals on mononuclear cells and chondrocytes. The association between osteoarthritis (OA) and IA calcifications has been the subject of several epidemiological publications, suggesting that calcium crystals are associated with a greater risk of progression of knee OA. Research in the field of calcium crystal deposition diseases is active: the areas of investigation for the coming years are broad and promising.

Radiometry in a comprehensive assessment of the effectiveness of extracorporeal shock wave therapy of calcifying tendinobursopathy of the shoulder

Introduction. Uncomfortable working conditions and excessive professional loads on the shoulder joints cause a high prevalence of degenerative-dystrophic changes in the periarticular tissues. Calcifying tendinitis and bursitis occupy a special place, characterized by multifocal accumulation of calcium phosphate crystals in tendons, mucous bags and muscles. The study is devoted to solving the problem of optimizing the X-ray diagnostics of the evolution of calcifying tendinobursopathy of the shoulder (CTS) in the dynamic assessment of the effectiveness of extracorporeal shock wave therapy.
 The aims of the study to optimize the X–ray diagnosis of calcifying tendinobursopathy of the shoulder in people working under the influence of adverse production factors.
 Materials and methods. The authors conducted a comparative retrospective analysis of the results of a comprehensive dynamic clinical and X-ray examination of 155 able-bodied men aged 35-57 years with an average work experience of 14.5±2.7 years (miners, loaders, bricklayers) examined for pain syndrome and dysfunction in the shoulder joint. The main group (65 people) are patients with CTS clinic, the presence of calcifications in the periaricular tissues of the rotator cuff and in the biceps muscle of the shoulder, evaluated in dynamics after shock wave therapy (SWT) of the shoulder in the phases of rest, resorption and recovery. The comparison group (90 people) consisted of patients with the absence of instrumentally detectable signs of multifocal accumulation of calcium phosphate crystals in the periarticular tissues of the shoulder. The study included patients whose routine conservative treatment proved ineffective. The following criteria for the effectiveness of therapy were identified: pain at rest, measured using a visual analog scale (VAS); dimensions (calcification area (in mm2)); optical density and calcification density gradient. Specialists evaluated the data at the initial stage of the study before the use of therapy, immediately after treatment and 12 months after the final SWT session.
 Results. In patients of the main group with the presence of CTS, the main manifestations of shoulder-scapular periarthritis (SSP) both in the main group and in the comparison group were moderately pronounced, however, the frequency of detection of the main SSP syndromes, primarily rotator cuff lesion, as well as background pathology (arthrosis of the shoulder joint) and acromioclavicular joint) were significantly higher in the main group. The effectiveness of SWT was demonstrated by regression of pain syndrome and positive dynamics of density characteristics of periarticular tissues of shoulder joints in areas of interest (in anatomotopographic projections of localization of tendons, mucous bags and muscles). In all patients of the main group, the decalcification process was characterized by both a visually perceptible pattern of disintegration and a decrease in its area, and a decrease in optical density immediately after the end of treatment. In 36.9% of patients, 12 months after the start of SWT, the X-ray and X-ray densitometric picture confirmed the prolongation of the decalcification process up to complete lysis of foci and calcification sites.
 Conclusions. In a comprehensive assessment of the effectiveness of CTS therapy, along with traditional X-ray diagnostics, special methodological techniques of radiometry (X-ray diffraction and X-ray densitometry in areas of interest) can be used, allowing for more accurate and more objective reflection of the direction of the dynamics of changes.
 The use of X-ray calcifications in the arsenal of methodological techniques, such as area, optical density and optical density gradient, can significantly improve the quality of diagnosis and avoid the use of computed tomography and an increase in radiation exposure to the patient.
 High-energy extracorporeal shockwave therapy is largely able to solve the problem of treating resistant forms of calcifying tendinobursopathy of the shoulder.

In Vitro evaluation of anti-urolithiatic activity of Piper betle L.

Urolithiasis or kidney stone is the most frequently occurring urinary disorders seen all over the world. They are saturated crystals formed due to the minerals present in the urine. It majorly comprises calcium oxalate, uric acid and phosphate crystals. The phosphate crystals, known as struvite, are formed due to the urinary tract infections. Although there are various synthetic medications, the use of traditional medicines / plants has been a promising method to treat kidney stones. To investigate the antiurolithiatic potential of traditional plant - Piper betle, the aqueous extract of Piper betle leaves was used. This extract was tested on two different crystals, first onto the raphides present in Colocasia esculenta leaf which is analogous to the calcium oxalate crystals. Second on the struvite crystals prepared from the crystallization method. The study showed there was a considerable decrease in the amount of raphides present in Colocasia esculenta and the same effect was seen on struvite crystals, which reveals that the leaves of Piper betle have an effect in dissolving and/or minimising the size of both crystals, thus substantiating the traditional claim. It is concluded that the leaves of Piper betle have beneficial inhibitory effect on in vitro crystallization of calcium oxalate and struvite crystals.