Study on reconstruction of rabbit alveolar bone defect with strontium-containing brushite bone ce-ments / 实用医学杂志

Objective To investigate whether 5% strontium-containing brushite bone cements(DCPD) has repair effect on alveolar bone defects in osteoporotic rabbits. Methods Eighteen healthy adult female rabbits were used to establish osteoporosis models and were randomly divided into three groups:the blank control group, DCPD group,doped 5%DCPD group(5%strontium),with 6 rats in each group.In addition to the blank group, rats the other groups were filled with the corresponding bone cements in the bilateral alveolar bone defects. At 4 weeks and 8 weeks after operation,3 rats in each group were killed and given shooting the defect area X-ray.The expression of b-FGF was detected by immunohistochemistry. Results X-ray results showed that the defected of doped 5% DCPD group have been nearly completedat the 8 week,DCPD group partially completed repair,but blank group was not fully repaired. The results of immunohistochemistry showed that the expression of b-FGF was the highest at 4 weeks and decreased at 8 weeks after operation.Expression of b-FGF was significantly different at 4 weeks and 8 weeks among the three groups.Conclusion The 5%strontium-containing brushite bone cements can repair bone defect in osteoporotic rabbits.

Síntesis de monetita pura por reacción heterogénea ácido-base / Synthesis of pure monetite by heterogeneous acid-base reaction / Síntese de monetita pura por reação heterogênea ácido-base

Resumen Se estudiaron cinco variaciones del procedimiento de síntesis de monetita modificando la agitación, la velocidad de adición de acido fosfórico, la homogenización y la temperatura de secado. Los productos se caracterizaron por difracción de rayos X (DRX), microscopia electrónica de barrido (SEM-EDS), relación Ca/P (por titulación de calcio con permanganato de potasio y valoración colorimétrica de fósforo por la formación del complejo azul de molibdeno) y espectroscopia infrarroja con transformada de Fourier (FTIR). Los resultados de DRX, espectroscopia infrarroja y la relación Ca/P señalan que el fosfato sintetizado corresponde a monetita pura. Se encontró que los factores de síntesis que más afectan las propiedades de composición, estructura cristalina, relación Ca/P y forma y tamaño de grano de los fosfatos sintetizados son la relación estequiométrica de los reactantes y la mecanoactivación de sólido con sobrenadante.

Abstract Five variations of the monetite (M) synthesis were evaluated modifying the stirring, the phosphoric acid addition rate, the homogeneity and the drying temperature. Products were assessed by means of XRD, FTIR, SEM-EDS analysis and chemical assay of Ca/P (calcium by titration with potassium permanganate and phosphorus by colorimetric assessment of the molybdenum blue complex). X-ray diffraction, infrared spectroscopy and Ca/P ratio indicate that the synthesized phosphate corresponds to pure monetite. It was found that the most influential factors affecting grain composition, crystal size, shape and structure as well as Ca/P molar ratio of synthesized phosphates were stoichiometry and ballmilling mechanoactivation.

Resumo Foram estudadas cinco variações do método de síntese de monetita (M) modificando a agitação, a velocidade de adicáo do acido fosfórico, a homogeneização e a temperatura de secagem. Os produtos foram caracterizados por difratometria de raios X (DRX), microscopia eletrônica de varredura (SEM-EDS), relação Ca/P (Titulação de cálcio com permanganatode potassio e titulação de fósforo pela avaliação colorimetrica do complexo azul de molibdenio), e espectrometria no infra-vermelho com transformada de Fourier (FTIR). Os resultados de DRX, FTIR e relação Ca/P indicam que o fosfato sintetizado corresponde a monetita pura. Foi encontrado que os fatores de sintese que mais afeitam as propriedades da composição, estrutura cristalina, relação Ca/P e a forma e tamanho de grão dos fosfatos sintetizados são a proporção estequiométrica e a mecânoativação do solido com o sobrenadante.

The effects of brushite coating extract with strontium on the osteoblast-related factor expression of MC3T3-E1 cells / 实用口腔医学杂志

Objective:To study the effects of brushite coating with strontium on the osteoblast-related factor expression of MC3T3-E1 cells.Methods:Brushite coating on tinanium surface was prepared by electrochemical deposition and the extract of the coating with stronium at 0.1%,0.5% and 1% were prepared respectively.MC3T3-E1 cells were cultured with the extracts,cell prolifera-tion,ALP activity,bFGF and VEGF mRNA were examined by MTT assay,ALP staining and RT-PCR respectively.Results:Stronti-um containing extracts promoted the proliferation,increased the ALP activity and mRNA expression of bFGF and VEGF(P <0.05)of MC3T3 cells.Conclusion:Brushite extract containing strontium may promote osteogenic function of MC3T3-E1 cells.

Effect of biomolecules from human renal matrix of calcium oxalate monohydrate (CaOx) stones on in vitro calcium phosphate crystallization

PURPOSE: Investigate the activity of high and low molecular weight biomolecules present in the matrix of human calcium oxalate (CaOx) stones not only on the initial mineral phase formation of calcium and phosphate (CaP) but also on its growth and demineralization of the preformed mineral phase. MATERIALS AND METHODS: Surgically removed renal stones were analyzed by Fourier Transform Infra Red (FTIR) spectroscopy and only CaOx stones were extracted with 0.05M EGTA, 1 mM PMSF and 1 percent ß-mercaptoethanol. Renal CaOx stone extract was separated into > 10 kDa and < 10 kDa fractions by dialysis. Activity of both the fractions along with whole extract was studied on the three mineral phases of CaP assay system. RESULTS: It was interesting to observe that both high and low molecular weight biomolecules extracted from human renal matrix of calcium oxalate (CaOx) stones exhibited different roles in the three mineral phases of CaP. Whole extract exhibited inhibitory activity in all the three assay systems; however, mixed (stimulatory and inhibitory) activity was exhibited by the > 10 kDa and < 10 kDa fractions. SDS-PAGE analysis showed bands of 66 kDa, 80 kDa, 42 kDa in whole EGTA extract lane and > 10 kDa fraction lane. CONCLUSION: Both high and low molecular weight biomolecules extracted from human renal matrix of calcium oxalate (CaOx) stones have a significant influence on calcium and phosphate (CaP) crystallization.

Clinical Experience of the Brushite Calcium Phosphate Cement for the Repair and Augmentation of Surgically Induced Cranial Defects Following the Pterional Craniotomy

OBJECTIVE: To prevent temporal depression after the pterional craniotomy, this study was designed to examine the safety and aesthetic efficacy of the brushite calcium phosphate cement (CPC) in the repair and augmentation of bone defects following the pterional craniotomy. METHODS: The brushite CPC was used for the repair of surgically induced cranial defects, with or without augmentation, in 17 cases of pterional approach between March, 2005 and December, 2006. The average follow-up month was 20 with range of 12-36 months. In the first 5 cases, bone defects were repaired with only brushite CPC following the contour of the original bone. In the next 12 cases, bone defects were augmented with the brushite CPC rather than original bone contour. For a stability monitoring of the implanted brushite CPC, post-implantation evaluations including serial X-ray, repeated physical examination for aesthetic efficacy, and three-dimensional computed tomography (3D-CT) were taken 1 year after the implantation. RESULTS: The brushite CPC paste provided precise and easy contouring in restoration of the bony defect site. No adverse effects such as infection or inflammation were noticed during the follow-up periods from all patients. 3D-CT was taken 1 year subsequent to implantation showed good preservation of the brushite CPC restoration material. In the cases of the augmentation group, aesthetic outcomes were superior compared to the simple repair group. CONCLUSION: The results of this clinical study indicate that the brushite CPC is a biocompatible alloplastic material, which is useful for prevention of temporal depression after pterional craniotomy. Additional study is required to determine the long-term stability and effectiveness of the brushite calcium phosphate cement for the replacement of bone.