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1.
Pan Afr Med J ; 38: 408, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34381552

RESUMO

Hydroxyapatite crystal deposition disease (HADD) of the hand and wrist is rare but can cause acute inflammatory syndromes that mimic infectious arthritis. These symptoms, which rapidly resolve with systemic anti-inflammatory drugs, are a source of diagnostic errors and inappropriate treatment. It is of crucial importance to make the diagnosis in order to avoid iatrogenic surgical management. The aim of this study was to determine the clinical and radiographic signs and the key features on which diagnosis depends. Treatment effectiveness and the course of the disease were also examined. Between 1992 and 2008, 12 patients consulted for an isolated acute local inflammatory syndrome of the hand or wrist, which was accompanied by a unique radiographic picture of calcific density. All patients were reassessed clinically and radiographically with a minimum follow-up of 2 years. All patients had presented with acute local inflammatory syndromes. Nine patients had edema and 8 had swelling and erythema. No patient had fever. The course was favorable in 11 patients and one patient required surgery. No patient had a recurrence at the mean final follow-up of 90 ± 64 months. The symptoms associated with hydroxyapatite crystal deposits suggest septic arthritis with acute joint inflammation. The radiological appearance is characteristic and corrects the diagnosis. Oral anti-inflammatory treatment gives more rapid spontaneous improvement, with complete and long-lasting resolution.


Assuntos
Calcinose/diagnóstico por imagem , Durapatita/metabolismo , Mãos/diagnóstico por imagem , Punho/diagnóstico por imagem , Adulto , Idoso , Anti-Inflamatórios/administração & dosagem , Artrite Infecciosa/diagnóstico , Calcinose/patologia , Calcinose/terapia , Edema/etiologia , Feminino , Seguimentos , Mãos/patologia , Humanos , Inflamação/diagnóstico por imagem , Inflamação/patologia , Masculino , Pessoa de Meia-Idade , Radiografia , Estudos Retrospectivos , Punho/patologia
2.
Biomolecules ; 11(8)2021 08 02.
Artigo em Inglês | MEDLINE | ID: mdl-34439803

RESUMO

Developing multifunctional systems for the biomimetic remineralization of human enamel is a challenging task, since hydroxyapatite (HAP) rod structures of tooth enamel are difficult to replicate artificially. The paper presents the first report on the simultaneous use of chitosan (CS) and agarose (A) in a biopolymer-based hydrogel for the biomimetic remineralization of an acid-etched native enamel surface during 4-10-day immersion in artificial saliva with or without (control group) fluoride. Scanning electron microscopy coupled with energy-dispersive X-ray spectrometry, Fourier transform infrared and Raman spectroscopies, X-ray diffraction, and microhardness tests were applied to investigate the properties of the acid-etched and remineralized dental enamel layers under A and CS-A hydrogels. The results show that all biomimetic epitaxial reconstructed layers consist mostly of a similar hierarchical HAP structure to the native enamel from nano- to microscale. An analogous Ca/P ratio (1.64) to natural tooth enamel and microhardness recovery of 77.4% of the enamel-like layer are obtained by a 7-day remineralization process in artificial saliva under CS-A hydrogels. The CS component reduced carbonation and moderated the formation of HAP nanorods in addition to providing an extracellular matrix to support growing enamel-like structures. Such activity lacked in samples exposed to A-hydrogel only. These data suggest the potential of the CS-A hydrogel in guiding the formation of hard tissues as dental enamel.


Assuntos
Materiais Biomiméticos/farmacologia , Quitosana/farmacologia , Esmalte Dentário/efeitos dos fármacos , Durapatita/química , Sefarose/farmacologia , Remineralização Dentária/métodos , Condicionamento Ácido do Dente/métodos , Materiais Biomiméticos/química , Tampões (Química) , Quitosana/química , Esmalte Dentário/fisiologia , Esmalte Dentário/ultraestrutura , Durapatita/metabolismo , Humanos , Hidrogéis/química , Hidrogéis/farmacologia , Teste de Materiais/métodos , Dente Molar/cirurgia , Saliva/química , Sefarose/química , Extração Dentária
3.
ACS Appl Mater Interfaces ; 13(33): 39142-39156, 2021 Aug 25.
Artigo em Inglês | MEDLINE | ID: mdl-34433244

RESUMO

The reconstruction of the intra/interfibrillar mineralized collagen microstructure is extremely important in biomaterial science and regeneration medicine. However, certain problems, such as low efficiency and long period of mineralization, are apparent, and the mechanism of interfibrillar mineralization is often neglected in the present literature. Thus, we propose a novel model of biomimetic collagen mineralization that uses molecules with the dual function of cross-linking collagen and regulating collagen mineralization to construct the intrafibrillar and interfibrillar collagen mineralization of the structure of mineralized collagen hard tissues. In the present study completed in vitro, N-2-(3,4-dihydroxyphenyl) acrylamide (DAA) is used to bind and cross-link collagen molecules and further stabilize the self-assembled collagen fibers. The DAA-collagen complex provides more affinity with calcium and phosphate ions, which can reduce the calcium phosphate/collagen interfacial energy to promote hydroxyapatite (HA) nucleation and accelerate the rate of collagen fiber mineralization. Besides inducing intrafibrillar mineralization, the DAA-collagen complex mineralization template can realize interfibrillar mineralization with the c-axis of the HA crystal on the surface of collagen fibers and between fibers that are parallel to the long axis of collagen fibers. The DAA-collagen complex, as a new type of mineralization template, may provide a new collagen mineralization strategy to produce a mineralized scaffold material for tissue engineering or develop bone-like materials.


Assuntos
Acrilamida/química , Materiais Biomiméticos/química , Colágeno/química , Dopamina/química , Osso e Ossos , Cálcio/química , Cálcio/metabolismo , Fosfatos de Cálcio/química , Reagentes para Ligações Cruzadas/química , Cristalização , Durapatita/química , Durapatita/metabolismo , Matriz Extracelular/metabolismo , Humanos , Simulação de Dinâmica Molecular , Polimerização , Medicina Regenerativa , Propriedades de Superfície , Engenharia Tecidual
4.
Sci Rep ; 11(1): 8290, 2021 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-33859236

RESUMO

Free heme is a highly toxic molecule for a living organism and its detoxification is a very important process, especially for carnivorous animals. Here we report the discovery of a previously unknown process for neutralizing free heme in the digestive tract of domestic cats. The cornerstone of this process is the encapsulation of heme into carbonated hydroxyapatite nanoparticles, followed by their excretion with faeces. This way of heme neutralization resembles the formation of insoluble heme-containing particles in the digestive tracts of other hematophagous species (for example, the formation of insoluble hemozoin crystals in malaria-causing Plasmodium parasites). Our findings suggest that the encapsulation of heme molecules into a hydroxyapatite matrix occurs during the transition from the acidic gastric juice to the small intestine with neutral conditions. The formation of these particles and their efficiency to include heme depends on the bone content in a cat's diet. In vitro experiments with heme-hydroxyapatite nanoparticles confirm the proposed scenario.


Assuntos
Trato Gastrointestinal/metabolismo , Heme/metabolismo , Ração Animal/análise , Animais , Gatos , Dieta/veterinária , Durapatita/metabolismo , Fezes , Suco Gástrico/metabolismo , Inativação Metabólica , Nanopartículas
5.
Food Funct ; 12(6): 2760-2771, 2021 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-33683238

RESUMO

This study investigated the behavior of nano-sized particles of hydroxyapatite (nHA) during dynamic in vitro gastrointestinal digestion, alone or dispersed within skim milk. The dissolution and the structural changes of nHA were investigated by analyzing the dissolution of calcium and using transmission electron microscopy and X-ray diffraction. The dissolution of nHA during gastric digestion involved a rapid early stage and a much slower later stage. It was incomplete by the end of gastric digestion, both with and without milk. However, there was no sign of nHA recrystallization in the intestinal phase. X-ray diffraction analysis of digesta showed the breakdown of the crystalline structure of nHA and the formation of potentially new calcium phosphate phases during digestion. Skim milk formed a structural clot and significantly retarded the dissolution of nHA during gastric digestion. Possible mechanisms leading to the incomplete dissolution of nHA and the matrix effect of milk are discussed.


Assuntos
Digestão/fisiologia , Durapatita , Leite , Nanopartículas , Animais , Cálcio/metabolismo , Durapatita/química , Durapatita/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Leite/química , Leite/metabolismo , Modelos Biológicos , Nanopartículas/química , Nanopartículas/metabolismo , Estômago/fisiologia
6.
Br J Radiol ; 94(1119): 20200234, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33417486

RESUMO

OBJECTIVES: To analyze vertebral fractures risk in patients with chest scans by evaluating vertebral hydroxyapatite concentration measured on spectral CT compared to trabecular attenuation value measured on conventional CT. METHODS: Our retrospective study reviewed CT of 216 patients. Analysis of vertebral (T11 - L1) hydroxyapatite concentration by spectral imaging and trabecular attenuation value by conventional CT imaging were performed in patients with chest CT examinations. Specificity, sensitivity, negative predictive value (NPV), and positive predictive value (PPV) were performed by using receiver operating characteristic (ROC) curves in patients with and without vertebral fractures. RESULTS: In male patients, vertebral hydroxyapatite concentration had high area under the ROC curve (0.916), by using the optimal threshold of 72.27 mg/cm3, specificity, sensitivity, NPV, and PPV were 91.7, 80.2, 36.7, and 98.7%, respectively. In female patients, vertebral hydroxyapatite concentration also had high area under the ROC curve (0.870), by using the optimal threshold of 74.79 mg/cm3, specificity, sensitivity, NPV, and PPV were 100.0, 77.8, 47.4, and 100.0%, respectively. Area under the ROC curve was significantly different between spectral CT-measured bone hydroxyapatite concentration and conventional CT-measured attenuation value in distinguishing vertebral fractures (p = 0.007 for males; p = 0.005 for females). CONCLUSIONS: Quantitative assessment with spectral CT may appear as higher accuracy than that of conventional CT imaging to analyze risk of vertebral fractures. Hydroxyapatite concentration measured with chest spectral CT may be used to evaluate risk of bone fractures. ADVANCES IN KNOWLEDGE: Hydroxyapatite concentration measured with chest spectral CT may be used to evaluate risk of bone fractures.


Assuntos
Durapatita/metabolismo , Radiografia Torácica/métodos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Idoso , Feminino , Humanos , Vértebras Lombares/diagnóstico por imagem , Vértebras Lombares/lesões , Vértebras Lombares/metabolismo , Masculino , Reprodutibilidade dos Testes , Estudos Retrospectivos , Medição de Risco , Sensibilidade e Especificidade , Fatores Sexuais , Fraturas da Coluna Vertebral/metabolismo , Vértebras Torácicas/diagnóstico por imagem , Vértebras Torácicas/lesões
7.
Chem Res Toxicol ; 34(3): 880-891, 2021 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-33507734

RESUMO

Uranium-238 (238U), a long-lived radiometal, is widespread in the environment because of both naturally occurring processes and anthropogenic processes. The ingestion or inhalation of large amounts of U is a major threat to humans, and its toxicity is considered mostly chemical rather than radiological. Therefore, a way to remove uranium ingested by humans from uranium-contaminated water or from the air is critically needed. This study investigated the uranium uptake by hydroxyapatite (HAP), a compound found in human bone and teeth. The uptake of U by teeth is a result of U transport as dissolved uranyl (UO22+) in contaminated water, and U adsorption has been linked to delays in both tooth eruption and development. In this present work, the influence of pH, contact time, initial U concentration, and buffer solution on the uptake and removal of U in synthetic HAP was investigated and modeled. The influence of pH (pH of human saliva, 6.7-7.4) on the uptake of uranyl was negligible. Furthermore, the kinetics were extremely fast; in one second of exposure, 98% of uranyl was uptaken by HAP. The uptake followed pseudo-second-order kinetics and a Freundlich isotherm model. A 0.2 M sodium carbonate solution removed all the uranyl from HAP after 1 h. Another series of in vitro tests were performed with real teeth as targets. We found that, for a 50 mg/L U in PBS solution adjusted to physiological pH, ∼35% of the uranyl was uptaken by the tooth after 1 h, following pseudo-first-order kinetics. Among several washing solutions tested, a commercially available carbonate, as well as a commercially available fluoride solution, enabled removal of all the uranyl taken up by the teeth.


Assuntos
Dente/metabolismo , Urânio/metabolismo , Durapatita/química , Durapatita/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Dente/química , Urânio/química , Urânio/isolamento & purificação
8.
J Cell Physiol ; 236(2): 1432-1444, 2021 02.
Artigo em Inglês | MEDLINE | ID: mdl-32853427

RESUMO

Revision operations have become a new issue after successful artificial joint replacements, and periprosthetic osteolysis leading to prosthetic loosening is the main cause of why the overactivation of osteoclasts (OCs) plays an important role. The effect of biochanin A (BCA) has been examined in osteoporosis, but no study on the role of BCA in prosthetic loosening osteolysis has been conducted yet. In this study, we utilised enzyme-linked immunosorbent assay, computed tomography imaging, and histological analysis. Results showed that BCA downregulated the secretion levels of tumor necrosis factor-α, interleukin-1α (IL-1α), and IL-1ß to suppress inflammatory responses. The secretion levels of receptor-activated nuclear factor-κB ligand, CTX-1, and osteoclast-associated receptor as well as Ti-induced osteolysis were also reduced. BCA effectively inhibited osteoclastogenesis and suppressed hydroxyapatite resorption by downregulating OC-related genes in vitro. Analysis of mechanisms indicated that BCA inhibited the signalling pathways of mitogen-activated protein kinase (P38, extracellular signal-regulated kinase, and c-JUN N-terminal kinase) and nuclear factor-κB (inhibitor κB-α and P65), thereby downregulating the expression of nuclear factor of activated T cell 1 and c-Fos. In conclusion, BCA may be an alternative choice for the prevention of prosthetic loosening caused by OCs.


Assuntos
Reabsorção Óssea/genética , Genisteína/farmacologia , Inflamação/genética , Osteogênese/genética , Osteoporose/genética , Animais , Artroplastia de Substituição/efeitos adversos , Reabsorção Óssea/induzido quimicamente , Reabsorção Óssea/patologia , Reabsorção Óssea/prevenção & controle , Linhagem Celular , Durapatita/química , Durapatita/metabolismo , MAP Quinases Reguladas por Sinal Extracelular/genética , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Humanos , Inflamação/induzido quimicamente , Inflamação/patologia , Inflamação/prevenção & controle , Interleucina-1alfa/genética , Interleucina-1beta/genética , Camundongos , NF-kappa B/genética , Osteoclastos/efeitos dos fármacos , Osteoclastos/patologia , Osteólise/genética , Osteólise/patologia , Osteólise/prevenção & controle , Osteoporose/induzido quimicamente , Osteoporose/patologia , Osteoporose/prevenção & controle , Próteses e Implantes/efeitos adversos , Transdução de Sinais/efeitos dos fármacos , Titânio/toxicidade , Fator de Necrose Tumoral alfa/genética
9.
Ned Tijdschr Geneeskd ; 1642020 12 02.
Artigo em Holandês | MEDLINE | ID: mdl-33332058

RESUMO

This case concerns a 62-year-old lady with persistent right knee pain. A conventional radiograph and additional MRI scan showed Hydroxyapatite crystal deposition disease (HADD) of the medial head of the gastrocnemius muscle. This was treated with a course of NSAIDs and functional weight-bearing mobilisation.


Assuntos
Biomineralização , Calcinose/diagnóstico , Joelho/fisiopatologia , Músculo Esquelético/metabolismo , Dor Musculoesquelética/diagnóstico , Anti-Inflamatórios não Esteroides/uso terapêutico , Calcinose/complicações , Durapatita/metabolismo , Feminino , Humanos , Imageamento por Ressonância Magnética , Pessoa de Meia-Idade , Dor Musculoesquelética/etiologia , Radiografia , Suporte de Carga
10.
ACS Synth Biol ; 9(12): 3334-3343, 2020 12 18.
Artigo em Inglês | MEDLINE | ID: mdl-33237760

RESUMO

Nanostructures formed by self-assembled peptides have been increasingly exploited as functional materials for a wide variety of applications, from biotechnology to energy. However, it is sometimes challenging to assemble free short peptides into functional supramolecular structures, since not all peptides have the ability to self-assemble. Here, we report a self-assembly mechanism for short functional peptides that we derived from a class of fiber-forming amyloid proteins called curli. CsgA, the major subunit of curli fibers, is a self-assembling ß-helical subunit composed of five pseudorepeats (R1-R5). We first deleted the internal repeats (R2, R3, R4), known to be less essential for the aggregation of CsgA monomers into fibers, forming a truncated CsgA variant (R1/R5). As a proof-of-concept to introduce functionality in the fibers, we then genetically substituted the internal repeats by a hydroxyapatite (HAP)-binding peptide, resulting in a R1/HAP/R5 construct. Our method thus utilizes the R1/R5-driven self-assembly mechanism to assemble the HAP-binding peptide and form hydrogel-like materials in macroscopic quantities suitable for biomineralization. We confirmed the expression and fibrillar morphology of the truncated and HAP-containing curli-like amyloid fibers. X-ray diffraction and TEM showed the functionality of the HAP-binding peptide for mineralization and formation of nanocrystalline HAP. Overall, we show that fusion to the R1 and R5 repeats of CsgA enables the self-assembly of functional peptides into micron long fibers. Further, the mineral-templating ability that the R1/HAP/R5 fibers possesses opens up broader applications for curli proteins in the tissue engineering and biomaterials fields.


Assuntos
Durapatita/metabolismo , Proteínas de Escherichia coli/metabolismo , Peptídeos/metabolismo , Durapatita/química , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Nanoestruturas/química , Peptídeos/genética , Plasmídeos/genética , Plasmídeos/metabolismo , Agregados Proteicos , Subunidades Proteicas/genética , Subunidades Proteicas/metabolismo
11.
Sci Rep ; 10(1): 20172, 2020 11 19.
Artigo em Inglês | MEDLINE | ID: mdl-33214599

RESUMO

Early microcalcification is a feature of coronary plaques with an increased propensity to rupture and to cause acute coronary syndromes. In this ex vivo imaging study of coronary artery specimens, the non-invasive imaging radiotracer, 18F-fluoride, was highly selective for hydroxyapatite deposition in atherosclerotic coronary plaque. Specifically, coronary 18F-fluoride uptake had a high signal to noise ratio compared with surrounding myocardium that makes it feasible to identify coronary mineralisation activity. Areas of 18F-fluoride uptake are associated with osteopontin, an inflammation-associated glycophosphoprotein that mediates tissue mineralisation, and Runt-related transcription factor 2, a nuclear protein involved in osteoblastic differentiation. These results suggest that 18F-fluoride is a non-invasive imaging biomarker of active coronary atherosclerotic mineralisation.


Assuntos
Doença da Artéria Coronariana/diagnóstico por imagem , Doença da Artéria Coronariana/metabolismo , Durapatita/metabolismo , Radioisótopos de Flúor/farmacocinética , Adulto , Idoso , Cadáver , Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Doença da Artéria Coronariana/fisiopatologia , Feminino , Radioisótopos de Flúor/metabolismo , Humanos , Masculino , Pessoa de Meia-Idade , Técnicas de Cultura de Órgãos , Osteogênese/fisiologia , Osteopontina/metabolismo , Placa Aterosclerótica/diagnóstico por imagem , Placa Aterosclerótica/metabolismo , Placa Aterosclerótica/patologia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Análise Espectral Raman , Microtomografia por Raio-X/métodos
12.
J Mater Chem B ; 8(45): 10373-10383, 2020 12 07.
Artigo em Inglês | MEDLINE | ID: mdl-33112349

RESUMO

Amelogenin and its various derived peptides play important roles in promoting biomimetic mineralization of enamel. Previously, an amelogenin-derived peptide named QP5 was proved to be able to repair demineralized enamel. The objective here was to interpret the mechanism of QP5 by elucidating the specific function of each domain for further sequence and efficacy improvement. Peptide QP5 was separated into domains (QPX)5 and C-tail. (QPX)3 was also synthesized to investigate how QPX repeats affect the mineralization process. Circular dichroism spectroscopy showed that two (QPX) repeats adopted a ß-sheet structure, while C-tail exhibited a disordered structure. (QPX)5 showed more absorption in confocal laser scanning microscopy observation and a higher K value in Langmuir adsorption isotherms compared to C-tail, while (QPX)3 with better hydropathy had greater adsorption capability than (QPX)5. Meanwhile, calcium consumption kinetics, transmission electron microscopy and selected area electron diffraction indicated that (QPX)5, C-tail and (QPX)3 had similar inhibitory effects on the spontaneous calcium consumption and the morphology of their nucleation products were alike, while QP5 had a greater inhibitory effect than them and induced elongated plate-like crystals. X-Ray diffraction further showed that both C-tail and (QPX)3 had greater potential in improving the apatite crystal orientation degree. In conclusion, (QPX)5 was the major adsorption region, both (QPX)5 and C-tail inhibited the nucleation, and C-tail contributed more to improve the HAP orientation degree, so QP5 could exert a significant remineralization effect. By reducing two repeats, (QPX)3 showed higher hydropathicity than (QPX)5 and achieved higher binding affinity, and it was more potential in improving the HAP orientation degree with lower economic cost.


Assuntos
Amelogenina/química , Amelogenina/farmacologia , Durapatita/metabolismo , Fragmentos de Peptídeos/química , Fragmentos de Peptídeos/farmacologia , Amelogenina/síntese química , Sequência de Aminoácidos , Calcificação Fisiológica/efeitos dos fármacos , Esmalte Dentário/metabolismo , Humanos , Fragmentos de Peptídeos/síntese química
13.
Int J Mol Sci ; 21(18)2020 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-32906793

RESUMO

In the field of tissue engineering, there are several issues to consider when designing biomaterials for implants, including cellular interaction, good biocompatibility, and biochemical activity. Biomimetic mineralization has gained considerable attention as an emerging approach for the synthesis of biocompatible materials with complex shapes, categorized organization, controlled shape, and size in aqueous environments. Understanding biomineralization strategies could enhance opportunities for novel biomimetic mineralization approaches. In this regard, mussel-inspired biomaterials have recently attracted many researchers due to appealing features, such as strong adhesive properties on moist surfaces, improved cell adhesion, and immobilization of bioactive molecules via catechol chemistry. This molecular designed approach has been a key point in combining new functionalities into accessible biomaterials for biomedical applications. Polydopamine (PDA) has emerged as a promising material for biomaterial functionalization, considering its simple molecular structure, independence of target materials, cell interactions for adhesion, and robust reactivity for resulting functionalization. In this review, we highlight the strategies for using PDA to induce the biomineralization of hydroxyapatite (HA) on the surface of various implant materials with good mechanical strength and corrosion resistance. We also discuss the interactions between the PDA-HA coating, and several cell types that are intricate in many biomedical applications, involving bone defect repair, bone regeneration, cell attachment, and antibacterial activity.


Assuntos
Biomineralização/efeitos dos fármacos , Indóis/farmacologia , Polímeros/farmacologia , Engenharia Tecidual/métodos , Animais , Biomimética/métodos , Regeneração Óssea/efeitos dos fármacos , Osso e Ossos/efeitos dos fármacos , Osso e Ossos/metabolismo , Adesão Celular/efeitos dos fármacos , Materiais Revestidos Biocompatíveis/química , Durapatita/química , Durapatita/metabolismo , Humanos , Indóis/metabolismo , Osteogênese/efeitos dos fármacos , Polímeros/metabolismo , Engenharia Tecidual/tendências
14.
Microbiol Immunol ; 64(11): 719-729, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32918493

RESUMO

Abiotrophia defectiva is a species of nutritionally variant streptococci that is found in human saliva and dental plaques and that has been associated with infective endocarditis. In our previous study, it was found that A. defectiva could bind specifically to saliva-coated hydroxyapatite beads (SHA). This study identified a cell surface component of A. defectiva that promotes adherence to SHA beads. The binding of A. defectiva to SHA was reduced in the presence of antibodies against human proline-rich protein (PRP); these results suggested that PRP may be a critical component mediating interactions between A. defectiva and the salivary pellicle. Two-dimensional gel electrophoresis of whole A. defectiva cells followed by Far-Western blotting was conducted by probing with synthetic peptides analogous to the binding region of PRP known as PRP-C. The results indicate that an A. defectiva protein of 37 kDa interacts with PRP-C. The results of amino-terminal sequencing of the adhesive A. defectiva protein revealed significant similarity to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Recombinant GAPDH bound to immobilized PRP-C in a dose-dependent manner and binding of A. defectiva to SHA or to PRP was reduced in the presence of anti-GAPDH antiserum. Western blotting or electron immunomicroscopic observations with anti-GAPDH antiserum revealed that this protein was expressed in both cytosolic and cell wall fractions. These results suggest that A. defectiva could specifically bind to PRP via interactions with cell surface GAPDH; the findings suggest a mechanism underlying A. defectiva-mediated adherence to saliva-coated tooth surfaces.


Assuntos
Abiotrophia/metabolismo , Aderência Bacteriana , Durapatita/metabolismo , Gliceraldeído-3-Fosfato Desidrogenases/metabolismo , Saliva/microbiologia , Proteínas Salivares Ricas em Prolina/metabolismo , Abiotrophia/genética , Sequência de Aminoácidos , Escherichia coli/genética , Gliceraldeído-3-Fosfato Desidrogenases/química , Gliceraldeído-3-Fosfato Desidrogenases/genética , Humanos , Peptídeos , Prolina , Streptococcus/metabolismo
15.
Arch Anim Nutr ; 74(5): 343-361, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32940083

RESUMO

Intensive selection in modern lines of fast-growing chickens has caused several skeletal disorders. Therefore, current research is focused on methods to improve the bones of birds. A new potential solution is in ovo technology using nanoparticles with a high specificity for the bone tissue. Thus, the objective of the present study was to evaluate the effect of in ovo application of hydroxyapatite nanoparticles (HA-NP) in different concentrations (50, 100 and 500 µg/ml colloids) on chicken embryo development, with a particular focus on the oxidative status and bone characteristics of the embryo. The results showed that in ovo treatment with HA-NP did not negatively affect hatchability and body weight. However, bone weight was reduced in 500 µg/ml group. The concentrations of calcium, phosphorus and crude ash were not affected. The modulatory effect of HA-NP was observed on the basis of antioxidative markers - superoxide dismutase, total antioxidant status, malondialdehyde in serum and selected tissues. Glutathione concentration in serum suggested higher metabolic stress. Among bone turnover markers, the concentration of osteocalcin was found to be significantly affected by HA-NP injection. Thus, the in ovo application of HA-NP could modify the molecular responses at the stage of embryogenesis but these changes were not reflected in embryo growth and even slowed down bone development. Nevertheless, the question for the follow-up research is whether in ovo administration of HA-NP would affect the antioxidative status and bone turnover resulting in improved bone conditions and body gain in post hatch chickens.


Assuntos
Calcificação Fisiológica/efeitos dos fármacos , Embrião de Galinha/efeitos dos fármacos , Durapatita/metabolismo , Nanopartículas/metabolismo , Óvulo/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Fenômenos Fisiológicos da Nutrição Animal , Animais , Embrião de Galinha/crescimento & desenvolvimento , Relação Dose-Resposta a Droga , Durapatita/administração & dosagem , Injeções/veterinária , Nanopartículas/administração & dosagem , Distribuição Aleatória
16.
J Orthop Surg Res ; 15(1): 406, 2020 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-32928246

RESUMO

BACKGROUND: Porous titanium alloy scaffold fabricated by 3D printing technology could induce osseointegration well to repair bone defect during early postoperative period. However, trabecular histomorphological features and chemical compositions of ingrowth bone in the long term after surgery still lacked in-depth research. METHODS: Fourteen New Zealand rabbits were divided into two groups (7 rabbits in surgery group and 7 rabbits in control group). A 3D-printed porous titanium alloy scaffold was implanted into right femoral condyle of each rabbit in the surgery group. Preload was produced at the surface between bone tissue and scaffold through interference assembly during implantation process. Rabbits in the control group were feed free. All rabbits were sacrificed to extract femoral condyles at week 12 after surgery. All right femoral condyles were performed micro-CT scanning to test bone mineral density (BMD) and trabecular histomorphological parameters, including bone volume fraction (BV/TV), bone surface/volume ratio (BS/BV), bone surface density (BS/TV), structure model index (SMI), trabecular thickness (Tb.Th), trabecular number (Tb.N), trabecular separation (Tb.Sp), porosity (PO), connectivity density (Conn.Dn), and degree of anisotropy (DA). Scanning electron microscope was used to observe osteogenesis peri-scaffold. Fourier transform infrared spectroscopy (FTIR) scanning was performed to analyze chemical compositions of peri-scaffold trabeculae. All trabecular morphological parameters and BMDs were statistically analyzed between surgery group and control group. RESULTS: The pores of scaffold were filled with ingrowth bone tissues after 12 weeks osseointegration. However, the mean BMD peri-scaffold in surgery group was 800 ± 20 mg/cm3, which was 18.37% lower than that in the control group. There was a significant decrease in BV/TV, Tb.N, and BS/TV, and there was a significant increase in Tb.Sp and PO between the surgery group and control group (p < 0.05). There were no significant differences in Tb.Th, SMI, Conn.Dn, BS/BV, and DA. Although ingrowth of bone tissue was very effective, some fragmented connective tissues were still found instead of bone tissues on the partial beams of scaffolds through SEM images. It was found from FTIR that there was no significant hydroxyapatite peak signal in surgery group. Collagen in the control group mainly existed as cross-link structure, while non-cross-link structure in the surgery group. CONCLUSIONS: Preload could promote the same good osseointegration ability as chemical surface modification method in the early term after surgery, and better osseointegration effect than chemical surface modification method in the mid-long term after surgery. However, histomorphological features of peri-scaffold trabeculae were still in deterioration and low collagen maturity caused by stress shielding. It was suggested from this study that extra physical training should be taken to stimulate the bone remodeling process for recovering to a healthy level.


Assuntos
Osso Esponjoso/metabolismo , Osso Esponjoso/fisiopatologia , Regiões de Interação com a Matriz/fisiologia , Osseointegração/fisiologia , Tecidos Suporte , Ligas , Animais , Densidade Óssea , Osso Esponjoso/diagnóstico por imagem , Osso Esponjoso/patologia , Colágeno/metabolismo , Durapatita/metabolismo , Tamanho do Órgão , Porosidade , Período Pós-Operatório , Impressão Tridimensional , Coelhos , Titânio , Microtomografia por Raio-X
17.
J Struct Biol ; 212(1): 107592, 2020 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-32736073

RESUMO

The mineralized extracellular matrix of bone is an organic-inorganic nanocomposite consisting primarily of carbonated hydroxyapatite, fibrous type I collagen, noncollagenous proteins, proteoglycans, and diverse biomolecules such as pyrophosphate and citrate. While much is now known about the mineralization-regulating role of pyrophosphate, less is known about the function of citrate. In order to assess the effect of negatively charged citrate on collagen mineralization, citrate-functionalized, bone osteoid-mimicking dense collagen gels were exposed to simulated body fluid for up to 7 days to examine the multiscale evolution of intra- and interfibrillar collagen mineralization. Here, we show by increases in methylene blue staining that the net negative charge of collagen can be substantially augmented through citrate functionalization. Structural and compositional analyses by transmission and scanning electron microscopy (including X-ray microanalysis and electron diffraction), and atomic force microscopy, all demonstrated that citrate-functionalized collagen fibrils underwent extensive intrafibrillar mineralization within 12 h in simulated body fluid. Time-resolved, high-resolution transmission electron microscopy confirmed the temporal evolution of intrafibrillar mineralization of single collagen fibrils. Longer exposure to simulated body fluid resulted in additional interfibrillar mineralization, all through an amorphous-to-crystalline transformation towards apatite (assessed by X-ray diffraction and attenuated total reflection-Fourier-transform infrared spectroscopy). Calcium deposition assays indicated a citrate concentration-dependent temporal increase in mineralization, and micro-computed tomography confirmed that >80 vol% of the collagen in the gels was mineralized by day 7. In conclusion, citrate effectively induces mesoscale intra- and interfibrillar collagen mineralization, a finding that advances our understanding of the role of citrate in mineralized tissues.


Assuntos
Calcificação Fisiológica/fisiologia , Ácido Cítrico/metabolismo , Colágeno Tipo I/metabolismo , Géis/metabolismo , Animais , Apatitas/metabolismo , Biomimética/métodos , Osso e Ossos/metabolismo , Durapatita/metabolismo , Matriz Extracelular/metabolismo , Microscopia Eletrônica de Varredura/métodos , Ratos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Difração de Raios X/métodos , Microtomografia por Raio-X/métodos
18.
Int J Mol Sci ; 21(16)2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32784986

RESUMO

This study aimed to develop polyvinyl alcohol (PVA) -based scaffold enriched with hyaluronic acid (HA) and hydroxyapatite (HAp) using physical crosslinking by freezing-thawing method. We accomplished biological evaluation of scaffolds, swelling degree, bioactivity assessment, and hemolytic test. The results showed that all types of scaffolds should be safe for use in the human body. The culturing of human osteoblast-like cells MG-63 and their proliferation showed better adhesion of cells due to the presence of HA and confirmed better proliferation depending on the amount of HAp. This paper gives the optimal composition of the scaffold and the optimal amount of the particular components of the scaffold. Based on our results we concluded that the best PVA/HA/HAp combination is in the ratio 3:1:2.


Assuntos
Materiais Biocompatíveis/metabolismo , Durapatita/metabolismo , Ácido Hialurônico/metabolismo , Osteoblastos/metabolismo , Álcool de Polivinil/metabolismo , Engenharia Tecidual/métodos , Tecidos Suporte/química , Materiais Biocompatíveis/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Durapatita/farmacologia , Humanos , Ácido Hialurônico/farmacologia , Hidrogéis/química , Teste de Materiais/métodos , Álcool de Polivinil/farmacologia
19.
PLoS One ; 15(8): e0237726, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32813737

RESUMO

In this in vitro study, spherical mesoporous bioactive glass nanoparticle (MBGN) and non-porous bioactive glass nanoparticle (BGN) were fabricated. The impact of mesopores on dentinal tubule occlusion and bioactivity was compared to examine the potential of these materials in alleviating dentine hypersensitivity (DH). MBGN, dense BGN were synthesized by sol-gel methods and characterized. Bioactivity and ion dissolution ability were analyzed. Twenty-four simulated sensitive dentin discs were prepared and randomly divided into three groups (n = 8 each); Group 1, no treatment; Group 2, Dense BGN; Group 3, MBGN. Then, four discs per group were treated with 6wt.% citric acid challenge to determine the acidic resistance. The effects on dentinal tubule occlusion were observed by FESEM. The microtensile bond strength (MTBS) was also measured. Cytotoxicity was examined using the MTT assay. According to the results, dense BGN without mesopore and MBGN with mesopore were successfully fabricated. Dense BGN and MBGN occluded the dentinal tubule before and after acid challenge. However, only MBGN formed a membrane-like layer and showed hydroxyapatite formation after soaking SBF solution. There were no significant differences in MTBS among dense BGN, MBGN (P>0.05). The cell viability was above 72% of both materials. The higher bioactivity of MBGN compared with that of dense BGN arises from the structural difference and it is anticipated to facilitate dentin remineralization by inducing hydroxyapatite deposition within the dentinal tubule.


Assuntos
Dessensibilizantes Dentinários/administração & dosagem , Sensibilidade da Dentina/terapia , Dentina/efeitos dos fármacos , Vidro/química , Nanopartículas/administração & dosagem , Dente Pré-Molar , Dentina/metabolismo , Dessensibilizantes Dentinários/química , Dessensibilizantes Dentinários/farmacocinética , Permeabilidade da Dentina/efeitos dos fármacos , Sensibilidade da Dentina/patologia , Liberação Controlada de Fármacos , Durapatita/metabolismo , Humanos , Teste de Materiais , Microscopia Eletrônica de Varredura , Nanopartículas/química , Nanopartículas/ultraestrutura , Porosidade , Propriedades de Superfície , Resistência à Tração , Remineralização Dentária/métodos , Difração de Raios X
20.
Sci Rep ; 10(1): 10576, 2020 06 29.
Artigo em Inglês | MEDLINE | ID: mdl-32601412

RESUMO

The global burden of bone-related diseases is increasing in the aging society; thus, improved bone targeted imaging for their early identification and treatment are needed. In this study, we screened novel peptide ligands for hydroxyapatite, a major inorganic component of teeth and bones, and identified a peptide enabling in vivo bone targeting and real-time fluorescence bone detection. To isolate peptides highly specific for hydroxyapatite, we used negative and positive selection from a randomized 8-mer peptide phage library and identified hydroxyapatite-specific peptides (HA-pep2, HA-pep3, and HA-pep7). Among these three peptides, HA-pep3 showed the highest binding capacity and superior dissociation constant towards hydroxyapatite surfaces over time (~ 88.3% retained on hydroxyapatite after two weeks). Furthermore, HA-pep3 was highly specific for hydroxyapatite compared to other calcium salt-based materials. Using this superior specificity, HA-pep3 showed higher accumulation in skull, spine, and joints in comparison with scrambled control peptide during real-time whole-body imaging. Ex vivo analysis of the major organs and bone from mice demonstrated that the fluorescence intensity in bone was about 3.32 folds higher in the case of HA-pep3 than the one exhibited by the scrambled control peptide. Our study identified a novel approach for targeting ligands for bone specific imaging and can be useful for drug delivery applications.


Assuntos
Osso e Ossos/diagnóstico por imagem , Osso e Ossos/metabolismo , Durapatita/química , Sequência de Aminoácidos/genética , Animais , Sistemas de Liberação de Medicamentos , Durapatita/metabolismo , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Imagem Óptica/métodos , Biblioteca de Peptídeos , Peptídeos/genética , Peptídeos/metabolismo , Tomografia Computadorizada por Raios X/métodos
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