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1.
Front Psychol ; 12: 704724, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34539506

RESUMO

Cognitive diagnostic test design (CDTD) has a direct impact on the pattern match ratio (PMR) of the classification of examinees. It is more helpful to know the quality of a test during the stage of the test design than after the examination is taken. The theoretical construct validity (TCV) is an index of the test quality that can be calculated without testing, and the relationship between the PMR and the TCV will be revealed. The TCV captures the three aspects of the appeal of the test design as follows: (1) the TCV is a measure of test construct validity, and this index will navigate the processes of item construction and test design toward achieving the goal of measuring the intended objectives, (2) it is the upper bound of the PMR of the knowledge states of examinees, so it can predict the PMR, and (3) it can detect the defects of test design, revise the test in time, improve the efficiency of test design, and save the cost of test design. Furthermore, the TCV is related to the distribution of knowledge states and item categories and has nothing to do with the number of items.

2.
Exp Physiol ; 106(10): 2124-2132, 2021 10.
Artigo em Inglês | MEDLINE | ID: mdl-34347918

RESUMO

NEW FINDINGS: What is the central question of this study? Massive infusion can destroy the endothelial glycocalyx. We compared the serum concentrations of endothelial glycocalyx components and atrial natriuretic peptide and the outcomes of patients with different levels of stroke volume variation (SVV). What is the main finding and its importance? With a decrease in SVV, the serum concentrations of endothelial glycocalyx components and atrial natriuretic peptide increased, whereas the oxygenation index decreased. When the intraoperative SVV was maintained at 7-10%, the patients had better postoperative recovery and shorter postoperative hospital stays. Therefore, it is advisable to maintain the SVV between 7 and 10%. ABSTRACT: Dynamic haemodynamic parameters, such as stroke volume variation (SVV), can be used for blood volume monitoring. However, studies have determined the SVV threshold but not the optimal level. The endothelial glycocalyx (EG) plays an important role in maintaining vascular permeability. Moreover, rapid and massive infusion can lead to the degradation, shedding and destruction of the EG. We aimed to explore the effects of different SVV values (11-14, 7-10 or 3-6%) on the EG in 54 patients who were scheduled for elective colorectal tumour surgery and to identify the optimal peri-operative fluid therapy strategy. The concentrations of EG degradation products (heparin sulphate, hyaluronic acid and syndecan-1) and atrial natriuretic peptide were higher when the SVV was maintained between 3 and 6% after fluid therapy compared with pre-infusion (P < 0.05). Comparison of postoperative complications and hospitalization time among the three SVV levels was not statistically significant (P > 0.05). The postoperative hospitalization time in patients with SVV of 7-10% was shorter than that in patients with SVV of 3-6%. Infusion of a large volume of fluid, with increasing EG degeneration and atrial natriuretic peptide concentrations, might be related to postoperative outcomes.


Assuntos
Cirurgia Colorretal , Glicocálix , Volume Sanguíneo , Hidratação , Glicocálix/metabolismo , Humanos , Volume Sistólico
3.
Front Mol Biosci ; 8: 681669, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34222336

RESUMO

The application of transbronchial lung cryobiopsy (TBLC) and uniportal and tubeless video-assisted thoracic surgery (UT-VATS) in the multidisciplinary diagnosis of interstitial lung disease (ILD) has not been demonstrated in real-world clinical practice. This prospective study included 137 patients with no definitive diagnosis who were the subject of two multidisciplinary discussion (MDD) sessions. As indicated in the first MDD, 67 patients underwent UT-VATS and 70 underwent TBLC. The specificity of biopsy information and its contribution to final MDD diagnosis were evaluated in the second MDD. The post-operative complications and hospitalization costs associated with the two biopsy methods were compared. UT-VATS was favored for patients initially diagnosed with idiopathic pulmonary fibrosis (IPF), bronchiolitis-associated interstitial lung disease (RB-ILD)/desquamative interstitial pneumonia (DIP) and undefined idiopathic interstitial pneumonia (UIIP), while TBLC was preferred for pulmonary lymphangioleiomyomatosis (PLAM) and pulmonary alveolar proteinosis (PAP). The spirometry parameters were better in patients who underwent UT-VATS than those who underwent TBLC. UT-VATS provided more specific pathological results than TBLC (85.7 vs 73.7%, p = 0.06). In patients initially diagnosed with UIIP, pathological information from UT-VATS was more clinically useful than that obtained from TBLC, although both tests contributed similarly to cases initially diagnosed as interstitial pneumonia with auto-immune features (IPAF)/connective tissue disease-related ILD (CTD-ILD). The safety of UT-VATS was comparable with TBLC although TBLC was cheaper during hospitalization (US$4,855.7 vs US$3,590.9, p < 0.001). multidisciplinary discussion decisions about biopsies were driven by current knowledge of sampling and diagnosis capacity as well as potential risks of different biopsy methods. The current MDD considered UT-VATS more informative than TBLC in cases initially diagnosed as UIIP although they were equally valuable in patients initially diagnosed with IPAF/CTD-ILD.

4.
J Cell Mol Med ; 2021 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-34132029

RESUMO

Vascular smooth muscle cells (VSMCs) senescence contributes to abdominal aortic aneurysm (AAA) formation although the underlying mechanisms remain unclear. This study aimed to investigate the role of miR-199a-5p in regulating VSMC senescence in AAA. VSMC senescence was determined by a senescence-associated ß-galactosidase (SA-ß-gal) assay. RT-PCR and Western blotting were performed to measure miRNA and protein level, respectively. The generation of reactive oxygen species (ROS) was evaluated by H2DCFDA staining. Dual-luciferase reporter assay was used to validate the target gene of miR-199a-5p. VSMCs exhibited increased senescence in AAA tissue relative to healthy aortic tissue from control donors. Compared with VSMCs isolated from control donors (control-VSMCs), those derived from patients with AAA (AAA-VSMCs) exhibited increased cellular senescence and ROS production. Angiotensin II (Ang II) induced VSMC senescence by promoting ROS generation. The level of miR-199a-5p expression was upregulated in the plasma from AAA patients and Ang II-treated VSMCs. Mechanistically, Ang II treatment significantly elevated miR-199a-5p level, thereby stimulating ROS generation by repressing Sirt1 and consequent VSMC senescence. Nevertheless, Ang II-induced VSMC senescence was partially attenuated by a miR-199a-5p inhibitor or Sirt1 activator. Our study revealed that miR-199a-5p aggravates Ang II-induced VSMC senescence by targeting Sirt1 and that miR-199a-5p is a potential therapeutic target for AAA.

5.
Front Bioeng Biotechnol ; 9: 643557, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33816454

RESUMO

In recent years, strontium-substituted calcium phosphate bone cement (Sr-CPC) has attracted more and more attentions in the field of bone tissue repair due to its comprehensive advantages of both traditional CPC and Sr ions. In this study, a crucial Sr-containing α-Ca3 - x Sr x (PO4)2 salt has been synthesized using a simplified one-step method at lower synthesis temperature. A novel Sr-CPC has been developed based on the simple binary Sr-containing α-Ca3 - x Sr x (PO4)2/Ca4(PO4)2O cement powder. The physicochemical properties and hydration mechanism of this Sr-CPC at various Sr contents were intensively investigated. The setting product of this Sr-CPC after a set for 72 h is a single-phase Sr-containing hydroxyapatite, and its compressive strength slightly decreased and its setting time extended with the increase of Sr content. The hydration process included the initial formation of the medium product CaHPO4⋅2H2O (30 min∼1 h), the following complete hydration of Ca4(PO4)2O and the initially formed CaHPO4⋅2H2O (2∼6 h), and the final self-setting of α-Ca3 - x Sr x (PO4)2 (6 h∼). The compressive strength of Sr-CPC, which was closely related to the transformation rate of Sr-containing hydroxyapatite, tended to increase with the extension of hydration time. In addition, Sr-CPC possessed favorable cytocompatibility and the effect of Sr ions on cytocompatibility of Sr-CPC was not obvious at low Sr contents. The present study suggests α-Ca3 - x Sr x (PO4)2 is a kind of vital Sr-containing salt source which is useful to develop some novel Sr-containing biomaterials. In addition, the new Sr-containing cement system based on this simple binary α-Ca3 - x Sr x (PO4)2/Ca4(PO4)2O cement powder displayed an attractive clinical application potential in orthopedics.

6.
Stem Cell Res Ther ; 12(1): 147, 2021 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-33632305

RESUMO

BACKGROUND: Idiopathic pulmonary fibrosis (IPF) is an age-related disease with no cure. Mesenchymal stem cell (MSC)-based therapy has emerged as a novel strategy for IPF treatment. Nevertheless, MSCs derived from patients with IPF (IPF-MSCs) become senescent, thereby reducing their beneficial effects in IPF. MicroRNAs (miRNAs) mediate the senescence of MSCs, but the underlying mechanisms are not fully understood. We investigated the mechanisms by which miR-199a-5p regulates IPF-MSC senescence and whether its inhibition could rejuvenate IPF-MSCs and enhance their therapeutic efficacy. METHODS: Control-MSCs and IPF-MSCs were isolated from the adipose tissue of age-matched healthy and IPF donors, respectively. Cell senescence was examined by senescence-associated ß-galactosidase (SA-ß-gal) staining. The level of miR-199a-5p was measured by RT-PCR. Autophagy was determined using a transmission electron microscope (TEM). The therapeutic efficacy of anti-miR-199a-5p-IPF-MSCs was assessed using a mouse model of bleomycin-induced lung fibrosis. RESULTS: Despite similar surface makers, IPF-MSCs exhibited increased cellular senescence and decreased proliferative capacity compared with control-MSCs. The expression of miR-199a-5p was significantly enhanced in the serum of IPF patients and IPF-MSCs compared with that of healthy donors and control-MSCs. The upregulation of miR-199a-5p induced senescence of control-MSCs, whereas the downregulation rescued IPF-MSC senescence. Mechanistically, miR-155-5p suppressed autophagy of MSCs via the AMPK signaling pathway by downregulating the expression of Sirtuin 1(Sirt1), resulting in cellular senescence. Accordingly, miR-155-5p inhibition promoted autophagy and ameliorated IPF-MSC senescence by activating the Sirt1/AMPK signaling pathway. Compared with IPF-MSCs, the transplantation of anti-miR-199a-5p-IPF-MSCs increased the ability to prevent progression of pulmonary fibrosis in bleomycin-treated mice. CONCLUSIONS: Our study shows that miR-199a-5p regulates MSC senescence in patients with IPF by regulating the Sirt1/AMPK signaling pathway and miR-199a-5p is a novel target to rejuvenate IPF-MSCs and enhance their beneficial effects.


Assuntos
Fibrose Pulmonar Idiopática , Células-Tronco Mesenquimais , MicroRNAs , Idoso , Senescência Celular , Humanos , Fibrose Pulmonar Idiopática/genética , Fibrose Pulmonar Idiopática/terapia , MicroRNAs/genética , Sirtuína 1
7.
Front Mol Biosci ; 8: 800747, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-35174208

RESUMO

Background and objective: Idiopathic pulmonary fibrosis (IPF) is an aggressive fibrotic pulmonary disease with spatially and temporally heterogeneous alveolar lesions. There are no early diagnostic biomarkers, limiting our understanding of IPF pathogenesis. Methods: Lung tissue from surgical lung biopsy of patients with early-stage IPF (n = 7), transplant-stage IPF (n = 2), and healthy controls (n = 6) were subjected to mRNA sequencing and verified by real-time quantitative PCR (RT-qPCR), immunohistochemistry, Western blot, and single-cell RNA sequencing (scRNA-Seq). Results: Three hundred eighty differentially expressed transcripts (DETs) were identified in IPF that were principally involved in extracellular matrix (ECM) remodeling, lipid metabolism, and immune effect. Of these DETs, 21 (DMD, MMP7, POSTN, ECM2, MMP13, FASN, FADS1, SDR16C5, ACAT2, ACSL1, CYP1A1, UGT1A6, CXCL13, CXCL5, CXCL14, IL5RA, TNFRSF19, CSF3R, S100A9, S100A8, and S100A12) were selected and verified by RT-qPCR. Differences in DMD, FASN, and MMP7 were also confirmed at a protein level. Analysis of scRNA-Seq was used to trace their cellular origin to determine which lung cells regulated them. The principal cell sources of DMD were ciliated cells, alveolar type I/II epithelial cells (AT cells), club cells, and alveolar macrophages (AMs); MMP7 derives from AT cells, club cells, and AMs, while FASN originates from AT cells, ciliated cells, and AMs. Conclusion: Our data revealed a comprehensive transcriptional mRNA profile of IPF and demonstrated that ECM remodeling, lipid metabolism, and immune effect were collaboratively involved in the early development of IPF.

8.
Respir Med ; 172: 105983, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-33032789

RESUMO

OBJECTIVES: To evaluate the efficacy and safety of ultra-low dose (100 mg) rituximab (RTX) administration in anti-melanoma differentiation-associated gene 5 (MDA5) positive patients with polymyositis/dermatomyositis (PM/DM) associated interstitial lung disease. METHODS: This retrospective study included anti-MDA5 antibody positive ILD subjects in the First Affiliated Hospital of Guangzhou Medical University from November 2017 to March 2019. Independent predictors for 180-day mortality were measured by Cox regression analysis. Patients were divided into 3 groups: Group 1 (non-cyclophosphamide (CTX)/RTX) (n = 10), Group 2 (CTX only) (n = 19) and Group 3 (RTX with/without CTX) (n = 11). The 180-day mortality was compared among 3 groups with Kaplan-Meier analysis. Post-RTX serological parameters as well as adverse events were evaluated. RESULTS: Forty patients were included with the mean age of 51.3 years. Elevated IL-10 level and CD4+/8+ ratio were considered as risk factors of 180-day mortality. Kaplan-Meier analysis showed a trend toward decrease, albeit non-significant, in 180-day mortality in Group 3 (P = 0.26). The administration of 100 mg RTX brought down B cell within 7 days that lasted for 180 days. There were 7 and 6 infection events observed within 2 months of CTX/RTX treatment in Group 2 and 3, with 5 and 2 fatal cases respectively. Cytomegalovirus infection accounted for half infection events in Group 3. CONCLUSION: We found a pronounced and prolonged B cell depletion following 100 mg RTX infusion and RTX add-on may be effective in anti-MDA5 positive ILD patients. However, infection, especially opportunistic infection, should be concerned during the treatment.


Assuntos
Autoanticorpos , Dermatomiosite/tratamento farmacológico , Dermatomiosite/imunologia , Helicase IFIH1 Induzida por Interferon/imunologia , Doenças Pulmonares Intersticiais/tratamento farmacológico , Doenças Pulmonares Intersticiais/imunologia , Polimiosite/tratamento farmacológico , Polimiosite/imunologia , Rituximab/administração & dosagem , Ciclofosfamida/administração & dosagem , Infecções por Citomegalovirus/complicações , Dermatomiosite/complicações , Dermatomiosite/mortalidade , Feminino , Humanos , Doenças Pulmonares Intersticiais/etiologia , Doenças Pulmonares Intersticiais/mortalidade , Masculino , Pessoa de Meia-Idade , Infecções Oportunistas/complicações , Polimiosite/complicações , Polimiosite/mortalidade , Estudos Retrospectivos , Fatores de Tempo , Resultado do Tratamento
9.
J Thorac Dis ; 12(7): 3688-3696, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32802448

RESUMO

BACKGROUND: Reported data on the disease spectrum of interstitial lung diseases (ILDs) of China are sparse and varied. We aimed to investigate the spectrum of ILDs and the distribution of diagnostic methods under a uniform diagnosis. METHODS: This retrospective study enrolled ILDs cases from Guangzhou Institute of Respiratory Health (GIRH). All cases were classified into specific subgroups of ILDs according to updated guidelines. RESULTS: A total of 1,945 subjects were enrolled from January 2012 to December 2017. The mean age was 57.9 years, and 1,080 (55.5%) patients were male. The most common subtype of ILDs was idiopathic pulmonary fibrosis (IPF, 20.3%), followed by interstitial pneumonia with autoimmune features (IPAF, 17.9%), connective tissue disease associated ILD (CTD-ILD, 18.3%) and unclassifiable idiopathic interstitial pneumonia (UIIP, 14.7%). A total of 818 (42.1%) patients underwent lung biopsy in order to obtain a histological diagnose. TBLB was performed in 565 (29.0%) patients, eleven of whom underwent SLB because TBLB failed to obtain lung samples. SLB was performed in 213 (11.0%) patients and TBCB was performed in 51 (2.6%) patients. Among them, histological results were considered clinically helpful in 722 (88.3%) cases, and provided definitive histopathological diagnoses in 368 cases. Surgical lung biopsy (SLB) was performed in 213 (10.9%) subjects, while 115 (54.0%) cases were performed among the idiopathic interstitial pneumonia (IIP). Among SLB cases in IIP, the highest rate of SLB was desquamative interstitial pneumonia/respiratory bronchiolitis-interstitial lung disease (DIP/RB-ILD, 10/10), lymphoid interstitial pneumonia (LIP, 9/9), followed by cryptogenic organizing (COP, 18/26), nonspecific interstitial pneumonia (NSIP, 22/53), IPF (43/395), UIIP (13/285). CONCLUSIONS: IPF was the most common ILDs in our ILD center, followed by IPAF, CTD-ILD and UIIP. Histological information may help to establish diagnostic algorithm in ILD.

10.
Oxid Med Cell Longev ; 2019: 1305049, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31885770

RESUMO

Mesenchymal stem cells (MSCs) have shown beneficial effects in the treatment of abdominal aortic aneurysm (AAA). Nonetheless, the biological properties of adipose-derived MSCs (ASCs) from patients with AAA (AAA-ASCs) remain unclear. This study is aimed at investigating the properties of cell phenotype and function of AAA-ASCs compared with ASCs from age-matched healthy donors (H-ASCs). H-ASCs and AAA-ASCs were studied for cell phenotype, differentiation capacity, senescence, and mitochondrial and autophagic functions. Cellular senescence was examined by senescence-associated ß-galactosidase (SA-ß-gal) staining. Mitochondrial morphology was determined by MitoTracker staining. Despite the similar surface markers of AAA-ASCs and H-ASCs, AAA-ASCs exhibited altered multidifferentiation potential. Compared with H-ASCs, AAA-ASCs displayed enhanced senescence manifested by increased SA-ß-gal activity and decreased proliferation and migration ability. Furthermore, AAA-ASCs showed increased mitochondrial fusion, reactive oxygen species (ROS) production, and decreased mitochondrial membrane potential. In addition, AAA-ASCs exhibited decreased autophagy level, upregulation of IL-6 and TNF-α secretion, and downregulation of IL-10 secretion compared with H-ASCs. Nonetheless, treatment of AAA-ASCs with rapamycin (an autophagy activator) dramatically reduced secretion of IL-6 and TNF-α and enhanced secretion of IL-10. In conclusion, our study showed that AAA-ASCs exhibit senescence phenomena and decreased cell function. Understanding the specific alterations in AAA-ASCs will help explore novel strategies to restore cell function for AAA treatment.


Assuntos
Aneurisma da Aorta Abdominal/patologia , Senescência Celular , Tecido Adiposo/citologia , Idoso , Aneurisma da Aorta Abdominal/metabolismo , Autofagia , Estudos de Casos e Controles , Movimento Celular , Proliferação de Células , Dano ao DNA , Feminino , Humanos , Masculino , Potencial da Membrana Mitocondrial , Células-Tronco Mesenquimais/citologia , Células-Tronco Mesenquimais/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , Pessoa de Meia-Idade , Mitocôndrias/metabolismo , Mitocôndrias/patologia , Espécies Reativas de Oxigênio/metabolismo
11.
Sci Rep ; 9(1): 6452, 2019 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-31015608

RESUMO

We aimed to evaluate the alteration of diagnosis of individual expert and multidisciplinary discussion (MDD) team in the longitudinal diagnostic assessment of idiopathic interstitial pneumonia (IIP). The retrospective analysis included 56 patients diagnosed as IIP by The First Affiliated Hospital of Guangzhou Medical University with follow-up visits during Jan 1st to Aug 31st 2014. Each expert was provided information in a sequential manner and was asked to assign an individual diagnosis and an MDD diagnosis after group discussion. The level of agreement among individual experts and between different visits was calculated by kappa and the agreement between individual specialist and MDD team with different consensus levels was measured by weighted-kappa coefficients. Follow-up data changed the original clinical diagnosis and MDD diagnosis in 24.1% and 10.7% of all cases, respectively, and clinician and MDD consensus level in 55.4% and 25.0%, respectively. The diagnostic performance of individual clinicians or radiologist was closer to that of the MDD compared with the pathologist, and follow-up further increased the agreement. The longitudinal evaluation of patients with IIP improved the inter-observer agreement in a multidisciplinary team. The performance of individual clinicians or radiologist was approaching the accuracy of multidisciplinary team when provided with follow-up data.


Assuntos
Algoritmos , Pneumonias Intersticiais Idiopáticas/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Idoso , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
12.
Inorg Chem ; 54(18): 9033-9, 2015 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-26355012

RESUMO

In this study, we demonstrate a facile and novel dual-ion-exchange method together with subsequent visible-light induced reduction for synthesis of mesoporous BiVO4/Ag/AgCl ternary heterostructured microspheres (HSMSs) with uniform size distribution. Using flower-like BiOCl microspheres as the starting material, and introducing NaVO3 and AgNO3 by a facile impregnation method, mesoporous BiVO4/AgCl HSMSs have been obtained through solid-phase dual-ion-exchange reactions at 400 °C for 2 h. Interestingly, it has been found that Ag(+) ions play an indispensable role on the dual-ion-exchange reactions, and then the BiVO4/AgCl HSMSs are converted into BiVO4/Ag/AgCl ternary HSMSs by a facile visible-light illumination for 2 h. The as-prepared mesoporous BiVO4/Ag/AgCl ternary HSMSs manifest high photocatalytic activity in degrading methyl orange (MO) and phenol under visible-light illumination, and a possible Z-scheme photocatalytic mechanism is proposed to understand the enhanced photochemical properties.

13.
PLoS One ; 7(8): e42525, 2012.
Artigo em Inglês | MEDLINE | ID: mdl-22905143

RESUMO

BACKGROUND: Polymethylmethacrylate bone cement cannot provide an adhesive chemical bonding to form a stable cement-bone interface. Bioactive bone cements show bone bonding ability, but their clinical application is limited because bone resorption is observed after implantation. Porous polymethylmethacrylate can be achieved with the addition of carboxymethylcellulose, alginate and gelatin microparticles to promote bone ingrowth, but the mechanical properties are too low to be used in orthopedic applications. Bone ingrowth into cement could decrease the possibility of bone resorption and promote the formation of a stable interface. However, scarce literature is reported on bioactive bone cements that allow bone ingrowth. In this paper, we reported a porous surface modified bioactive bone cement with desired mechanical properties, which could allow for bone ingrowth. MATERIALS AND METHODS: The porous surface modified bioactive bone cement was evaluated to determine its handling characteristics, mechanical properties and behavior in a simulated body fluid. The in vitro cellular responses of the samples were also investigated in terms of cell attachment, proliferation, and osteoblastic differentiation. Furthermore, bone ingrowth was examined in a rabbit femoral condyle defect model by using micro-CT imaging and histological analysis. The strength of the implant-bone interface was also investigated by push-out tests. RESULTS: The modified bone cement with a low content of bioactive fillers resulted in proper handling characteristics and adequate mechanical properties, but slightly affected its bioactivity. Moreover, the degree of attachment, proliferation and osteogenic differentiation of preosteoblast cells was also increased. The results of the push-out test revealed that higher interfacial bonding strength was achieved with the modified bone cement because of the formation of the apatite layer and the osseointegration after implantation in the bony defect. CONCLUSIONS: Our findings suggested a new bioactive bone cement for prosthetic fixation in total joint replacement.


Assuntos
Cimentos Ósseos , Células 3T3 , Alginatos/química , Animais , Reabsorção Óssea , Osso e Ossos/metabolismo , Carboximetilcelulose Sódica/química , Adesão Celular , Diferenciação Celular , Proliferação de Células , Força Compressiva , Feminino , Gelatina/química , Ácido Glucurônico/química , Ácidos Hexurônicos/química , Teste de Materiais , Camundongos , Microscopia Eletrônica de Varredura/métodos , Osteoblastos/citologia , Polimetil Metacrilato/química , Porosidade , Coelhos , Estresse Mecânico , Propriedades de Superfície
14.
J Mater Sci Mater Med ; 22(12): 2631-40, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21979165

RESUMO

Sr-contained calcium hydroxyapatite (SrCaHA) cement is a potential biomaterial for in vivo bone repair and surgery fixation due to its excellent biodegradability, bioactivity, biocompatibility, easily shaping and self-hardening. We had ever reported the in vitro physiochemical properties, biocompatibility and in vivo degradability of the SrCaHA cement obtained by mixing a cement powder of Ca(4)(PO(4))(2)O/CaHPO(4)/SrHPO(4) and a cement liquid of diluted H(3)PO(4) aqueous solution. In the present study, we intensively studied the influences of both Sr content and H(3)PO(4) concentration in diluted phosphoric acid aqueous solution on the setting time, hydration heat-liberation behaviours, and real-time microstructure and phase evolutions of the SrCaHA cement. The results show that both PO(4)(3-) and H(+) ions in PA solution attended the hydration reaction as reactants, and thus the increase of the PA concentration not only promoted the dissolution of Ca(4)(PO(4))(2)O but also pushed the hydration progress of SrCaHA bone cement. Sr content exhibits a remarkable retardation role on the apatite transformation of the SrCaHA cement pastes which probably attributed to its higher degree of supersaturation for yielding apatite crystals and lower transformation rate when exposed to the Sr(2+)-containing hydration system. This present results contribute to a better understanding on the hydration mechanism of the new SrCaHA cement and help to the more precisely controlling of its hydration process.


Assuntos
Materiais Biocompatíveis/química , Cimentos Ósseos/química , Durapatita/química , Ácidos Fosfóricos/química , Estrôncio/química , Implantes Absorvíveis , Cristalização , Temperatura Alta , Íons , Teste de Materiais , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Pós , Propriedades de Superfície , Difração de Raios X
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