OBJECTIVE: To study the preparation and properties of the hyaluronic acid (HA)/α-calcium sulfate hemihydrate (α-CSH)/β-tricalcium phosphate (β-TCP) material (hereinafter referred to as composite material). METHODS: Firstly, the α-CSH was prepared from calcium sulfate dihydrate by hydrothermal method, and the β-TCP was prepared by wet reaction of soluble calcium salt and phosphate. Secondly, the α-CSH and β-TCP were mixed in different proportions (10∶0, 9∶1, 8∶2, 7∶3, 5∶5, and 3∶7), and then mixed with HA solutions with concentrations of 0.1%, 0.25%, 0.5%, 1.0%, and 2.0%, respectively, at a liquid-solid ratio of 0.30 and 0.35 respectively to prepare HA/α-CSH/ β-TCP composite material. The α-CSH/β-TCP composite material prepared with α-CSH, β-TCP, and deionized water was used as the control. The composite material was analyzed by scanning electron microscope, X-ray diffraction analysis, initial/final setting time, degradation, compressive strength, dispersion, injectability, and cytotoxicity. RESULTS: The HA/α-CSH/β-TCP composite material was prepared successfully. The composite material has rough surface, densely packed irregular block particles and strip particles, and microporous structures, with the pore size mainly between 5 and 15 μm. When the content of β-TCP increased, the initial/final setting time of composite material increased, the degradation rate decreased, and the compressive strength showed a trend of first increasing and then weakening; there were significant differences between the composite materials with different α-CSH/β-TCP proportion ( P<0.05). Adding HA improved the injectable property of the composite material, and it showed an increasing trend with the increase of concentration ( P<0.05), but it has no obvious effect on the setting time of composite material ( P>0.05). The cytotoxicity level of HA/α-CSH/β-TCP composite material ranged from 0 to 1, without cytotoxicity. CONCLUSION The HA/α-CSH/β-TCP composite materials have good biocompatibility. Theoretically, it can meet the clinical needs of bone defect repairing, and may be a new artificial bone material with potential clinical application prospect.
Calcium Phosphates ; Bone and Bones ; Phosphates

Bone Cements ; Calcium ; Calcium Phosphates ; Materials Testing

BACKGROUND: High-density calcifications on CT images can appear as high signals on T1-weighted MR images, but with differing extents and degrees. This study investigated CT and MR images of calcifications of various types and concentrations. METHODS: We analyzed CT and MR images of two cases of bilateral basal ganglia calcifications and experimental suspensions of calcifications of different types and concentrations. RESULTS: The density of CT calcifications increased in proportion to their concentration regardless of their type. However, the MR signals differed with the types and concentrations of calcification. A high signal was one of the most noticeable signs on T1-weighted MR images for calcium phosphate, and it increased for concentrations up to 0.2 g/mL before leveling off. The signal for all types of calcification decreased on T2-weighted and especially fluid-attenuated inversion recovery (FLAIR) images. CONCLUSIONS: High signals are characteristic of calcification on T1-weighted MR images, and are often stronger than those on CT images. A low signal appears consistently on FLAIR MR images regardless of the calcification type. These findings might be helpful in evaluating calcifications apparent in MR images.
Basal Ganglia ; Brain ; Calcium ; Calcium Phosphates ; Magnetic Resonance Spectroscopy ; Suspensions

PURPOSE: The objective of this study was to investigate the effects of calcium phosphate coated titanium implant surface on bone response and implant stability at early stage of healing period of 3 weeks and later healing period of 6 weeks. MATERIAL AND METHODS: A total of 24 machined, screw-shaped implants (Dentium Co., Ltd., Seoul, Korea) which dimensions were 3.3 mm in diameter and 5.0 mm in length, were used in this research. All implants (n = 24), made of commercially pure (grade IV) titanium, were divided into 2 groups. Twelve implants (n = 12) were machined without any surface modification (control). The test implants (n = 12) were anodized and coated with thin film (150 nm) of calcium phosphate by electron-beam deposition. The implants were placed on the proximal surface of the rabbit tibiae. The bone to implant contact (BIC) ratios was evaluated after 3 and 6 weeks of implant insertion. RESULTS: The BIC percentage of calcium phosphate coated implants (70.8 +/- 18.9%) was significantly higher than that of machined implants (44.1 +/- 16.5%) 3 weeks after implant insertion (P = 0.0264). However, there was no significant difference between the groups after 6 weeks of healing (P > .05). CONCLUSION: The histomorphometric evaluation of implant surface revealed that: 1. After 3 weeks early healing period, bone to implant contact (BIC) percentage of calcium phosphate coated implants (70.8%) was much greater than that of surface untreated machined implants (44.1%) with P = 0.0264. 2. After 6 weeks healing period, however, BIC percentage of calcium phosphate coated implants group (79.0%) was similar to the machined only implant group (78.6%). There was no statistical difference between two groups (P = 0.8074). 3. We found the significant deference between the control group and experimental group during the early healing period of 3 weeks. But no statistical difference was found between two groups during the later of 6 weeks.
Calcium ; Calcium Phosphates ; Nitrogen Mustard Compounds ; Tibia ; Titanium

OBJECTIVE: To evaluate the biocompatibility and osteogenic effect of new calcium phosphate cement (CPC) in vivo and to provide experimental basis for its further clinical application. METHODS: Thirty New Zealand white rabbits were randomly divided into four groups: CPC group, CPC+Bio-Oss group, Bio-Oss group and blank control group. Bone defect models of 6 mm in diameter and 7 mm in depth were made on the lateral condyle of bilateral hind legs of the rabbits. CPC, Bio-Oss and CPC+Bio-Oss mixture were implanted into the bone defect according to the group, and the mass ratio of CPC and Bio-Oss was 4 ∶ 1. The experimental animals were sacrificed the 4th, 12th and 24th week after operation. The tissue around the bone defect was taken for histological evaluation by H&E staining. Bone ingrowth fraction (BIF) was calculated. The expression of BMP-2 and COL-Ⅰ was detected by immunohis- tochemical staining by calculating the mean optical density (MOD) of the positive area the 4th week after operation, and the bone healing of each group was evaluated at different time points. The measurement data were analyzed by one-way ANOVA and LSD test was used for multiple comparison of the differences between the means by SPSS 19.0. P < 0.05 was considered to be statistically significant. RESULTS: The results of H&E staining showed that the BIF values of CPC group, CPC + Bio-Oss group and Bio-Oss group were significantly higher than those of blank control group at the same time point (P < 0.01). The BIF values of CPC group were lower than those of Bio-Oss group and CPC + Bio-Oss group (P < 0.01). There was no significant difference between CPC + Bio-Oss group and Bio-Oss group. Immunohistochemical staining showed that the MOD values of BMP-2 and COL-Ⅰ in CPC group were higher than those in blank control group, but lower than those in Bio-Oss group and CPC+Bio-Oss group (P < 0.01). There was no significant difference between BMP-2 and COL-Ⅰ in CPC+Bio-Oss group and Bio-Oss group. CONCLUSION The new calcium phosphate cement has good biocompatibility and can promote early osteogenesis with stable and long-term effect.
Animals ; Bone Cements ; Calcium ; Calcium Phosphates ; Osteogenesis ; Rabbits ; Strontium

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.
Calcium ; Calcium Phosphates ; Craniotomy ; Depression ; Dinucleoside Phosphates ; Follow-Up Studies ; Humans ; Inflammation ; Physical Examination

Nephrocalcinosis is described as the deposition of calcium crystals in the renal parenchyma that result from prolonged states of hypercalcemia. Recently recognized is the deposition of calcium phosphate in the renal tubular injury by using sodium phosphate cathartics commonly used for the colonic cleansing. This phenomenon was termed phosphate nephropathy. Acute renal failure secondary to phosphate nephropathy has been increasingly recognized as a complication after the administration of sodium phosphate solution for colonoscopy. We report a case of acute phosphate nephropathy following oral sodium phosphate solution to cleanse the bowel for colonoscopy. A renal biopsy showed diffuse tubular calcium deposition.
Acute Kidney Injury ; Biopsy ; Calcium ; Calcium Phosphates ; Cathartics ; Colon ; Colonoscopy ; Hypercalcemia ; Nephrocalcinosis ; Phosphates ; Renal Insufficiency ; Sodium

OBJECTIVETo establish an in vitro model for the apatite crystal mineralization. To evaluate the influences of bovine serum albumin (BSA) and fluoride to the mineralization of apatite crystal.

METHODSThe model was constructed using cation selective membrane (CMV) and dialysis membrane. Double distilled water (DDW), BSA, 5, 20, 100 mg x L(-1) fluoride were added into the reaction space of the model. Reaction was carried out at 37 degrees C for 3 days under gentle stirring. The crystals were identified by scanning electron microscope (SEM) and X-ray diffraction (XRD).

RESULTSThe model was established successfully. When DDW and BSA were added respectively, the main component of the deposit was octacalcium phosphate (OCP), but the shape and size of the crystals differs from each other. When fluoride with different concentration were added, the main component of the crystal turned to rod-like and prism-like fluoroapatite (FAP) crystal. The size and crystallinity of the FAP increased with the increase of the fluoride concentration.

CONCLUSIONIt is an effective way to evaluate the influence factors of the apatite crystal mineralization by using the in vitro model.

Bone-like apatite formation on the surface of calcium phosphate ceramics has been believed to be the prerequisite of new bone growth on ceramics and to be related to the osteoinductivity of the material. The research of the factors effecting bone-like apatite formation is a great help in understanding the mechanism of osteoinduction. This paper is aimed to a comparative study of in vitro formation of bone-like apatite on the surface of dense and rough calcium phosphate ceramics with SBF flowing at different rates. The results showed that the rough surface was beneficial to the formation of bone-like apatite, and the apatite formed faster in 1.5 SBF than in SBF. Rough surface, namely, larger surface area, increased the dissolution of Ca2+ and HPO4(2-) and higher concentration of Ca2+ and HPO4(2-) ions of SBF and was in turn advantageous to the accumulation of Ca2+, HPO4(2-), PO4(3-) near the ceramic surface. Local supersaturating concentration of Ca2+, HPO4(2-), PO4(3-) near sample surface was essential to nucleation of apatite on the surface of sample.
Apatites ; Biocompatible Materials ; Calcium Phosphates ; Ceramics ; Materials Testing ; Surface Properties

OBJECTIVE: The Purpose of the study was to investigate the bone morphogenic protein expression of rhBMP-2(recombinant human bone morphogenic protein-2) as singnaling molecule and beta-TCP(Tricalcium phosphate) as a bone substitute and carrier medium of rhBMP-2. MATERIALS AND METHODS: 16 rabbits divided into 2 group of each 8 rabbit. Two standardized bone defect, round bilateral defect was made in the cranium of the 8 rabbit of first group, and was grafted with 150~500micrometer diameter beta-TCP 0.25g in one side, which was soaked with rhBMP-2, and autogenous bone was grafted on another side as a positive control. Second group of 8 rabbit, only beta-TCP was grafted with same size and same manner. After 2, 4, 8, and 12 weeks, specimen was taken for microscopic immunohiostochemical and histomorphometric analysis. RESULT: Grafting beta-TCP with rhBMP show the early formation of the bone regenerative factor (BMP-4) and more quantity of new bone formation than only use of beta-TCP (8,12 week), even show less new bone formation than autogenous bone. CONCLUSION: The experimental study result that beta-TCP graft combination with rhBMP-2 as a delivery system is an effective with osteoinductive capacity and biodegradable properties, so that provide clinical availibility of composite use in reconstruction of bony defect.
Bone Substitutes ; Calcium Phosphates ; Humans ; Immunohistochemistry ; Osteogenesis ; Rabbits ; Skull ; Transplants