Mineral Component Of Bone Tissue Research Articles

Determination of rare earth elements in synthetic calcium phosphates by high-resolution continuum source electrothermal atomic absorption spectrometry

Ceramic, cement and composite biomaterials have been developed based on hydroxyapatites (HA) and tricalcium phosphates (TCP), which are analogous in phase and chemical composition to the mineral component of bone tissue. The crystal structures of HA and TCP are arranged in isomorphic substitutions. Recently, research has focused on the modification of HA and TCP structures with ions of various metals, including rare earth ions (REEs), with the aim of creating materials with a range of beneficial properties for medical applications. REEs are known to have a number of useful properties, including antibacterial, antitumour, catalytic, magnetic and luminescent properties. The replacement of some of the Ca ions in the structures of HA and TCP with REE ions therefore makes it possible to obtain a material with biocompatibility and biological activity, giving it the required properties depending on the REE used and its concentration. In order to achieve the specified properties, it is necessary to control not only the structure (phase composition, lattice parameters of the powders) and the presence of characteristic functional groups, but also the chemical elemental composition. Modifications of hydroxyapatites and tricalcium phosphates containing from one to several different alloying elements are currently being developed. Various analytical methods are used for this purpose, including X-ray, atomic emission and a number of others. This article is devoted to the study of the analytical capabilities of the method of atomic absorption spectrometry with electrothermal atomization and a continuous spectrum source in relation to the determination of Eu and Yb in hydroxyapatites and tricalcium phosphates. The article considers the optimal conditions and modes of analysis, including temperature-time programs, the use of modifiers, the construction of calibration curves, and other factors that can be adjusted for more precise results. The results demonstrated the possibility of simultaneous determination of both Eu and Yb in the concentration range of 0.09 to 2 wt.%, with a relative standard deviation of less than 6 rel.%.

Hydroxylapatite of bone tissue: dynamics of crystallochemical alterations upon osteoporosis

Bone tissue is a physiogenic organomineral aggregate consisting of organic (collagen, fats, sugars) and mineral (hydroxlyapatite) components. Osteoporosis is one of the most common bone diseases leading to disruption of bone tissue mineralization processes. To study the dynamics of changes in
 hydroxylapatite during osteoporosis, an experiment was conducted on laboratory animals with the simulation of systemic osteoporosis using ovariectomy (the surgical removal of an ovary or ovaries). The chemical composition of the mineral component of bone tissue was studied using electron microprobe analysis with further statistical processing of the results. The osteoporosis of bone tissue results in an increase in the content of isomorphic Mg, Al, and K in hydroxylapatite. A signifcant role of Al in the development of the disease was established using multivariate statistics methods. The X-ray diffraction revealed the increase in the unit cell parameters of hydroxylapatite with the osteoporosis progression. The results of IR spectroscopy showed the presence of a carbonate group in hydroxylapatite, the content of which decreases with disease.

Evaluation of osteogenesis processes against the background of experimental osteoporosis therapy

Background. Osteoporosis is a problem all over the world with important clinical and economic consequences. A significant contribution to solving the problem of the spread of osteoporosis can be the creation of drugs based on unique biologically active compounds.
 The aim was to evaluate the processes of osteogenesis, according to the formation of an organic matrix of bone tissue, as well as to evaluate markers of bone remodeling in blood serum at the stages of anti-osteoporosis therapy.
 Materials and methods. The study was performed on an experimental model of osteoporosis using biochemical methods for analyzing markers of osteoporosis in blood serum, as well as atomic absorption spectroscopy and X-ray densitometry.
 Results. According to the results of the study, the specific anti-osteoporotic activity of the new drug based on succinic acid salts was proved - a significant increase in the organic component the total collagen in bone tissue and the mineral component - the main elements in bone tissue in both young and old senile animals. Evaluation of the dynamics of the content of markers of bone remodeling showed the high effectiveness of the new drug in monotherapy, and in combination with vitamin D3 in the activation of osteogenesis processes in experimental osteoporosis.
 Conclusion. The effectiveness of the proposed anti-osteoporotic agent is shown, which is more pronounced in senile rats and is due to a proportional increase in the organic and mineral components of bone tissue.

Osteocalcin role in the development and progression of cardiovascular diseases

Cardiovascular diseases have been the leading cause of death worldwide for a long time. Despite numerous studies on the pathogenetic mechanisms of cardiovascular diseases, there are many debatable issues. In recent years, an increasing number of scientific reports have appeared regarding the presence of common mechanisms in the deve­lopment of bone tissue and arterial calcification. One of the connecting links in this interaction is considered to be the impact of osteocalcin. Osteocalcin is a vitamin K-dependent protein of the bone matrix, synthesized by osteoblasts. The main function of osteocalcin is the synthesis of hydroxyapatites as main mineral component of bone tissue. In addition, osteocalcin has a wide range of extraosseous effects, the most studied is participation in the regulation of glycolipid and ener­gy metabolism. Research on the osteocalcin role in the development and progression of cardiovascular diseases are scarce, the available data is contradictory. For a deeper understanding of this problem, we conducted a systematic analysis of modern literature based on data from the scientific databases Medline (Pubmed), Scopus, Web of Science, Google Scholar, and Cochrane Library for 2013–2023. According to its results, osteocalcin is a potential biomarker of cardiovascular status, its increased values are associated with a potentially protective mechanism against the development of cardiovascular diseases. Contradictory views on the understanding of the pathogenetic mechanism of influence of general osteocalcin and its forms on the course of cardiovascular diseases necessitate conduction of further research.

CHANGES IN THE DENSITY AND COMPOSITION OF BONE TISSUE AND ALVEOLAR BONE ATROPHY IN RATS WITH HYPOTHIREOSIS AND CORRECTION WITH A COMPLEX OF MINERALS AND VITAMINS

Problem. For diseases of the thyroid gland, it is advisable to use hormone replacement therapy. However, numerous consequences of an overdose of L‑thyroxine drugs are known. The use of a preventive complex based on minerals, vitamins and quercetin can be an alternative to replacement therapy for correcting the consequences of disorders of the musculoskeletal system in thyroid diseases. Goal. The purpose of the work is an experimental study of the osteoprotective effectiveness of a complex of vitamins and minerals in rats with hypothyroidism. Method. In the experiment, 36 rats were used, which were divided into three groups: 12 intact, 12 animals that were simulated with hypothyroidism, and 12 rats that, against the background of hypothyroidism, were administered a preventive complex daily. The experiment on modeling hypothyroidism and its prevention lasted 4 months. Mandibles, lumbar vertebrae and femurs of rats of both sexes were isolated. Morphometric parameters were studied in vertebrae and femurs: density, content of mineral and organic components of bone tissue. The degree of atrophy of the alveolar process was determined in the jaws of the animals. Main results. Modeling hypothyroidism in rats caused a significant decrease in femoral bone density in males by 2.2% and in females by 1.7%, had no effect on lumbar vertebral density, and significantly increased alveolar process atrophy in males by 22.2% and in females by 15. 8%. The decrease in the density of the femur bone was due to a decrease in the content of the mineral component of bone tissue by 4.5–7.2%. The use of a preventive complex containing vitamins, minerals and quercetin led to an increase in the density of femurs to the level of healthy animals, increased the density of the lumbar vertebrae by 2.2–3.1%, and reduced atrophy of the alveolar process of the jaws in females by 21.5% and in males by 31.4%. Deterioration of the quality of bone tissue in thyroid insufficiency, as well as the osteotropic effectiveness of the prophylactic complex in conditions of hypothyroidism, were more pronounced in males. Conclusions. The conducted studies showed the development of dystrophic processes in the jaws and femurs of rats against the background of a deficiency of thyroid hormones and the positive effect of a complex of vitamins and minerals, which effectively stopped the atrophy of the alveolar process of the jaws and the decrease in the density of the femurs, and also increased the density of the lumbar vertebrae of rats with hypothyroidism.

FEATURES OF THE PREVENTION OF CARIES OF TEMPORARY TEETH IN CHILDREN IN THE MOUNTAIN REGIONS OF THE TRANSCARPATHIAN REGION

The aim of the study. Rationale for early prevention of caries of temporary teeth in children who have been living in the mountainous regions of Zakarpattia region for a long time.
 High indicators of the expansion and intensity of the caries process among children are associated with polyetiological caries, among which the leading place is occupied by the endemicity of the territory of residence, which in its course affects the changes in the morphological characteristics of the population and the metric parameters of the dentin and pulp of the temporary teeth of children who live permanently in the mountainous zone of the Transcarpathian region, which was confirmed by the conducted research.
 The mineral composition of the human body is a constant, especially in childhood, which directly depends on the intake of microand macroelements with food and drinking water. At the same time, the role of microand macroelements plays an important role for the full functioning of all organs and systems.
 The stability of the body's chemical composition is one of the most important and mandatory conditions for its normal functioning. Deviations of indicators of chemical elements from the norm, caused by environmental, professional, climate-geographical factors or diseases, lead to a wide range of violations of the health of the body. For example, out of 92 chemical elements found in nature, 81 are found in the human body.
 It is important to remember that today iodine deficiency diseases are an important medical and social problem, which is connected with biogeochemical indicators peculiar to the territory of Ukraine. And with diseases of the thyroid gland, all types of metabolism are disturbed, as a result of which metabolic changes are observed in the tissues of the teeth.
 It is generally accepted that the insufficient intake of fluorine and iodine in the human body leads to an imbalance in the processes of deand remineralization of enamel, and accordingly, reduces the level of caries resistance of tooth enamel, which leads to the destruction of the crystal lattice of enamel and the appearance of defects in the hard tissues of teeth.
 Based on this, such elements as fluorine and iodine play an important role in the formation of dental status, since iodine is involved in the synthesis of a number of hormones, which, in turn, determine the quality of the metabolism of a number of vitamins, affects the speed of biochemical reactions. And fluorine is the most important active substance in the prevention of caries and remineralization of enamel, the mechanism of action of which is that when it interacts with the mineral components of bone tissue and teeth, difficult-to-dissolve compounds are formed.
 It is worth remembering that fluorine also contributes to the precipitation of calcium phosphate from saliva, which determines the processes of remineralization during the initial carious process. The fact that it affects the enzymatic systems of dental plaque and saliva bacteria also plays a role in the mechanism of the anti-caries effect of fluoride.
 Caries prevention in such regions is, first of all, based on ensuring individual oral hygiene, rational nutrition with daily requirements of the necessary microand macroelements to maintain the mineralization of teeth, as well as implementation of remineralization therapy and deep fluoridation in order to enrich hydroxyapatites with fluorine and calcium molecules to suppress the progression of demineralization processes in the hard tissues of the teeth.

One-step fabrication of single-phase hydroxyapatite coatings on Ti-alloy implants by electrostatic spray deposition: From microstructural investigation to in vitro studies

The intrinsic characteristics of calcium phosphate-based ceramics (composition, crystallinity , morphology) enable them to be successfully used as osseoconductive coatings on load-bearing implants. Among these compounds, hydroxyapatite (HAP) is the leading material owing to its similarity with the mineral component of bone tissue. In this work, electrostatic spray deposition (ESD) using an organic phosphorus precursor was employed as a suitable one-step coating technique that might overcome the drawbacks of the widely used plasma-spraying process related to extremely high processing temperatures, such as unpredictable phase changes of the feedstock , particle release and delamination . The key ESD parameters (type of the solvent(s), total reagent concentration, nominal Ca/P ratio in the precursor solution, solution flow-rate, substrate temperature, and nozzle-to-substrate distance) were systematically studied to tune, precisely, the microstructure and the crystallite size of single-phase HAP coatings on Ti6Al4V substrates. In vitro studies with MG-63 osteoblast-like cells were performed during 24 h exposure to selected ESD-derived HAP coatings. All coatings were found to support cell viability. Moreover, the coating properties, i.e. , crystallite size and microstructure, played an extremely important role in the behavior of osteoblast-like cells. A higher cellular response was observed when low crystalline HAP coatings were employed. • HAP coatings fabricated in one-step on Ti6Al4V by electrostatic spray deposition. • In-depth study of ESD processing parameters to control HAP coating microstructure. • Independently tuning of the coating microstructure and the crystallite size of HAP. • Fabrication from thin dense HAP films to highly porous hierarchical structures. • Low crystalline HAP ESD films present a high in vitro MG-63 cytocompatibility.

АНАЛІЗ ДИНАМІКИ МІНЕРАЛЬНОГО СКЛАДУ КІСТКОВОЇ ТКАНИНИ НА ТЛІ ОПІОЇДНОГО ВПЛИВУ

Introduction. The modern scientific medical literature contains numerous data on the peculiarities of structural transformation of bone tissue and the dynamics of its mineral composition in the age aspect, as well as under the influence of various exo- and endogenous factors. However, data on changes in the mineral component of bone tissue under conditions of long-term opioid exposure have not been identified in the available literature, although the widespread use of opioids in the clinic as drugs with analgesic effect makes this issue especially relevant. The aim of our research was to study the dynamics of mineral composition of rat bone tissue with prolonged exposure to opioids. Materials and methods. The study was carried out on 40 sexually mature outbred male rats with a body weight of 180-200 g and aged 3.5 months. Opioid addiction was modeled by the daily (once a day with identical intervals) injection of an opioid pain reliever nalbuphine. Nalbuphine was injected intramuscularly using to the following pattern: 1st week - 8 mg/kg, 2nd week - 15 mg/kg, 3rd week - 20 mg/kg, 4th week - 25 mg/kg, 5th week - 30 mg/kg, 6th week - 35 mg/kg. To determine the mineral composition of the bone tissue of rat's mandible, the method of atomic absorption spectral analysis (AASA) was used, which made it possible to detect eight mineral elements (calcium, phosphorus, magnesium, sodium, potassium, iron, strontium, zinc) in the studied samples. The concentration of researched elements in bone tissue samples was specified in mg/g. The research of mineral composition of the mandible was performed weekly in the span of 7 weeks of the experiment - 6 weeks of nalbuphine consumption, and then one week after its cessation (5 animals per each experiment period); 5 other animals were attributed to the control group. Results. The results of this study allowed to determine the quantitative content of all investigated elements in the bone tissue at each stage of the experiment and indicate the presence of their expressed dynamics. Results of the atomic absorption spectral analysis of bone tissue of the rat's mandible body allowed to determine the quantitative content of four macro-elements (Ca, P, Mg, Na) and four microelements (K, Fe, Sr, Zn) and their specific shares in the mineral content of bone tissue in intact animals against the background of nalbuphine consumption and after its cessation. Against the background of nalbuphine consumption and after its cessation, specific shares of the studied macro-and microelements in the mineral component of bone tissue of the rat’s mandible have expressed dynamics - shares of calcium, iron, strontium, and zinc grow and remain higher than normal, and after nalbuphine is no longer administered, while specific shares of phosphorus, sodium, magnesium, and potassium are lower than in intact animals during seven weeks of the experiment. The dynamics of absolute indices of the researched mineral elements against the background of nalbuphine consumption and after its cessation differs from the dynamics of their specific shares. During six weeks of nalbuphine consumption, absolute levels of calcium, phosphorus, magnesium, sodium, zinc, and iron increase, remaining above the norm after its cessation; the amount of potassium decreases and remains lower than normal after nalbuphine withdrawal, while the amount of strontium decreases, though in the minimum, and after nalbuphine is no longer administered, it returns to the same value as in intact animals. Conclusions. Results of the study allowed to determine the absolute quantitative content of all researched elements and their specific shares in the mandible bone tissue at each stage of the experiment and showed evident dynamics, which is different for each of the researched indices.

Заживление оскольчатых переломов костей голени при использовании комплекса минералов «Мицеллат» (экспериментальное исследование)

Purpose Experimental study of the effect of Micellate on the processes of reparative regeneration on the model of comminuted tibial fractures. Materials and methods The paper analyzes the results of studies carried out on 20 mongrel dogs in whom comminuted tibial fractures were modeled. To stimulate osteogenesis, a complex of minerals called Micellate was used. Results It was found that Micellate acts selectively and restores the lack of the bone tissue mineral component. The regenerate remodels into an organotypic bone in a shorter time. Conclusion After a detailed study of the mechanisms of action and clinical trials, the preparation might find application both in the correction of osteopenia and osteoporosis that develop in the process of fracture consolidation, and for the prevention of fractures caused by the loss of the mineral component of bone tissue as a result of metabolic disturbances.

PHOTOCATALYTIC AND ANTIBACTERIAL ACTIVITY OF TITANIUM, FLUORINE AND SILVER CO-SUBSTITUTED HYDROXYAPATITE

Synthetic hydroxyapatite (HA), an analogue of the mineral component of bone tissue has been widely used in medicine as bone replacing material. To impart specific properties, HA can be chemically modified by anionic and cationic substitutions during synthesis. Thus the present study was focused in synthesizing nanocrystalline Ti , Ag and F co-substituted HA by microwave synthesis. The prepared powders were characterized by XRD and FTIR for their crystal size, cystallinity and functional groups respectively. XRD spectra reveal that crystal size of prepared powders was in the range of 21–25 nm in as synthesized condition and 45–51 nm in 900 ˚C heat-treated condition. Complete decomposition of HA to tri calcium phosphate was observed for Ti substituted HA powder after heat-treatment. Addition of F improved the thermal stability of Ti substituted HA as indicated by predominant phase of HA after heat-treatment. The photocatalytic activity of co-substituted HA powders was examined by degradation of methylene blue (5 × 10−5 M concentration) under visible light irradiation and the results were compared with pure HA . The degradation efficiency of co-substituted HA with respect to methylene blue was twice as high as that of pure HA. Ti and Ag has improved the visible light photocatalytic activity of HA, further F co-substitution has not affected the photocatalytic activity of substituted HA. The antibacterial effect of prepared powders was observed against 1 × 105 cells/mL of Escherichia coli using spread plate method at 24 h incubation period. Ag co-substituted HA showed complete inhibition of growth of Escherichia coli. Thus, among Ti , Ti-F , Ti-F-Ag substituted HA powders, Ti-F-Ag co-substituted HA with excellent visible light photocatalytic activity and anti-bacterial property is expected to be a potential candidate for biomedical applications.

Respective roles of organic and mineral components of bone tissue in micromechanical behavior of human cortical bone

Respective roles of organic and mineral components of bone tissue in micromechanical behavior of human cortical bone

Recent Progress on Hydroxyapatite-Based Dense Biomaterials for Load Bearing Bone Substitutes

Hydroxyapatite (HA) is the main mineral component of bone tissue, representing ca. 69 vol% in bone and up to 98 vol% in dental enamel. Its chemical composition close to the mineral phase of bone is the origin of its excellent biocompatibility to tissue bone. Hydroxyapatite has been applied in orthopaedics as block implants, porous, granules and coating material, either dense or porous. However, the application is restricted to non-load bearing application due to its brittleness and low toughness and flexural strength. With this, the development of bioactive dense HA is necessary as it has promising potential in application of load bearing bone implant. Few efforts have been made in developing many methods to produce dense HA. Some of the methods have been combined to prepare dense HA with improved properties. This paper will be discussing the recent progress on efforts which have been done in improving mechanical properties of hydroxyapatite-based dense type biomaterials for load bearing bone substitutes applications. Some recent patents related to dense calcium phosphate are also reviewed.

Synthesis of composite biomaterials in the hydroxyapatite-calcite system

New medical engineering processes for repair of human bone tissue damaged upon diseases or injury are based on implanting porous scaffolds made of bio� compatible materials with cultivated osteoforming cells into the defect site [1–5]. With time, this struc� ture is replaced by bone tissue formed de novo. Apart from biocompatibility with the body, the requirements to the scaffold material include also time coherence between the resorption and the formation of a new bone tissue. Materials based on calcium phosphates, especially hydroxyapatite (HA), which is analogous in the chemical and phase composition to the mineral component of bone tissue, is best suited for this pur� pose. However, HA is the calcium phosphate most resistant to resorption. The resorption kinetics can be controlled by introducing a second, more soluble phase to the HA. To this end, composite materials in the HA–tricalcium phosphate system were developed [4, 5]; however, these materials still suffer from a num�

The importance for growth of dietary intake of calcium and vitamin D

To investigate the role of dietary calcium and vitamin D in the process of growth and development of children and adolescents, focusing in particular on the prevention and treatment of delayed growth caused by nutritional deficiency. Information was gathered from articles published in the last 2 decades, from searches on the databases SciELO, PubMed and Medline, technical books and publications of international organizations. Growth is influenced by intrinsic (genetic and metabolic) and extrinsic factors (environmental factors such as diet, health, hygiene, housing and access to health services). Among the nutritional factors are vitamin and oligoelement deficiencies which may be associated with malnutrition or caused by insufficient absorption. Since calcium is one of the main mineral components of bone tissue, it is essential for adequate bone formation and, considering that vitamin D plays an important role in calcium metabolism, a diet with insufficient quantities of these nutrients can impact on the formation of the skeleton and on the process of growth and development. In children and adolescents, low intake or low absorption of calcium and vitamin D may limit their statural growth, and it is necessary to supply sufficient quantities of both during the critical growth phases.

Stabilization of Carbonate Hydroxyapatite by Isomorphic Substitutions of Sodium for Calcium

Carbonate hydroxyapatite (CHA) is an analogue of the mineral component of bone tissue. Synthetic CHA is thermally unstable: it readily decomposes with carbon oxide evolution when sintered to ceramics. Its thermal stability has been studied as affected by partial isomorphic substitution of sodium for calcium intended to compensate a possible charge imbalance induced by CO32− groups. Investigative tools were thermogravimetry and FTIR spectroscopy of the condensed vapor produced by heating CHA samples doped with 0.4 and 0.8 wt % sodium. Sodium does not improve the thermal stability of CHA: weight loss on heating increases with increasing sodium level; evolution of carbon oxides occurs at lower temperatures and more intensively. Sodium enhances the generation of B-type defects (CO32− → PO43− substitutions); these defects are thermodynamically less stable than AB-type defects (2CO32− → PO43−, OH− substitutions), which are characteristic of sodium-free CHA.

Effect of smoking on resorption of residual alveolar ridges in complete denture wearers

Based on literature data it is obvious that there is a connection between smoking and periodontal diseases. Alveolar bone loss increases with smoking. Tobacco smoking affects the proportion of subgingival bacterial flora by influencing oxidoreduction potential of dental plaque and thus making conditions for development of anaerobic bacteria. According to some researchers, smoking affects the mineral component of bone tissue. Orthopantomograms show higher level of alveolar bone loss in smokers than in nonsmokers with the same level of oral hygiene. The aim of this study was to establish if smoking affects alveolar bone loss in complete denture wearers. Our clinical investigation included 60 patients of both sexes (30 smokers and 30 nonsmokers) all complete dentures wearers. All patients met study criteria: jaw relation and smokers who smoke over 20 cigarettes per day. All subjects were interviewed, and after that orthopantomograms were made. They were used to calculate the degree of alveolar bone loss. The examined subjects were approximately of the same age. Mean age of smokers was 59.9 and nonsmokers 61.8. It was established that differences regarding resorption in men were not significant. The degree of resorption in women smokers and women non-smokers was different, but differences were not significant. It has been proven that the number of cigarettes smoked per day is very important. It is considered that the risk of oral epithelial dysplasia increases when smoking more than 20 cigarettes per day. Considering our results regarding resorption of edentulous alveolar ridge in smokers and nonsmokers, we concluded that there were no significant differences. There are opinions in literature that smoking is not an etiological factor in resorption, but there are some opinions that smoking is connected with the degree of resorption in periodontium. The analyses of resorptive changes in edentuolous smokers were done only around implants and it was estimated that smoking has more influence than other clinical risk factors. On the bases of our research we may conclude that smoking does not directly affect the degree of resorption of edentulous alveolar ridge with complete denture wearers.

Effect of compression on bone tissue crystals

The effect of compressive forces on the mineral components of bone tissue was studied. On the basis of x-ray diffraction analysis and the observed electrical and recrystallization effects, it is proposed that compression has a direct effect on the formation of callus through a definite means of compression osteosynthesis.

Effect of thyrocalcitonin on the mineral component of regenerating bone during healing of fractures

Changes in the state of the mineral component of bone tissue (hydroxyapatite) during reparative regeneration of bone after administration of thyrocalcitonin (TCT) were studied in experiments on rabbits. Methods of histology, quantitative microroentgenography, and x-ray diffraction were used. TCT has no marked stimulant effect on normal osteogenesis and mineralization of newly formed bone tissue. However, mineralization of the callus follows an optimal course and osteoporosis of the fragments is much less marked than in animals not receiving TCT.