Bone formation on calcium phosphate bone substitute materials

A large number of bone substitute materials are available; for which some authors claim osteoconductivity and some osteoinductivity. In order to rank these materials an in vivo analysis was carried out. These materials were chosen based on their availability and claimed mode of action. Silicon substituted Hydroxyapatite (SiHA), Hydroxyapatite (HA), Resorbable Calcium Phosphate Silicon, Skelite [siliconstabilized tricalcium phosphate-based bone substitute], Pro Osteon 500R [coralline HA], BiIonic [Yttrium stabilized SiHA] and two non-calcium phosphate, Dimeneralised Bone Matrix (DBM) based biomaterials: Accell Connexus DBM putty and Grafton crunch DBM were implanted in sheep femoral condyle defects for 6 weeks. Implanted calcium phosphate (CaP) based biomaterials demonstrated superior bone formation in comparison with the DBM samples. Silicon within CaPs increased the rate of bone formation in vivo. Silicon substituted HA showed increased proliferation rate (P<0.05) of human marrow stromal cells compared to pure HA in vitro. Expression of osteoblastic marker genes RUNX2, Osterix and Osteopontin within the hMSCs indicated the differentiation of preosteoblasts into osteoblasts, and osteogenic development on both HA and SiHA. Expression of osteocalcin and bone sialoprotein genes on HA and SiHA samples indicated the activation of mineralisation process. Differentiation of hMSCs into osteoblasts in vitro suggested a role in promotion of osteoinduction by both HA and SiHA. Implantation of porous SiHA and HA in paraspinous muscle of sheep, exhibited new bone formation through osteoinduction. SiHA indicated significantly higher new bone formation (P<0.01) compared to HA. SiHA and HA biomaterials with higher strut porosity (30%) indicated greater bone formation (P<0.05). In conclusion, CaP based biomaterials demonstrate superior bone formation in comparison with DBM biomaterials. Silicon substitution within HA enhances the cellular activity of hMSCs. Osteoinduction was greatest on SiHA with higher strut porosity. This result is believed to be due to a combination of the effect of interconnected porosity and chemical composition of the bone substitute

Intrinsic Osteoinductivity of Porous Titanium Scaffold for Bone Tissue Engineering

Large bone defects and nonunions are serious complications that are caused by extensive trauma or tumour. As traditional therapies fail to repair these critical-sized defects, tissue engineering scaffolds can be used to regenerate the damaged tissue. Highly porous titanium scaffolds, produced by selective laser sintering with mechanical properties in range of trabecular bone (compressive strength 35 MPa and modulus 73 MPa), can be used in these orthopaedic applications, if a stable mechanical fixation is provided. Hydroxyapatite coatings are generally considered essential and/or beneficial for bone formation; however, debonding of the coatings is one of the main concerns. We hypothesised that the titanium scaffolds have an intrinsic potential to induce bone formation without the need for a hydroxyapatite coating. In this paper, titanium scaffolds coated with hydroxyapatite using electrochemical method were fabricated and osteoinductivity of coated and noncoated scaffolds was compared in vitro. Alizarin Red quantification confirmed osteogenesis independent of coating. Bone formation and ingrowth into the titanium scaffolds were evaluated in sheep stifle joints. The examinations after 3 months revealed 70% bone ingrowth into the scaffold confirming its osteoinductive capacity. It is shown that the developed titanium scaffold has an intrinsic capacity for bone formation and is a suitable scaffold for bone tissue engineering

The effect of an alginate carrier on bone formation in a hydroxyapatite scaffold.

This study investigated the osteoconductive properties of a porous hydroxyapatite (HA) scaffold manufactured using a novel technique similar to the bread-making process, alone and in combination with an alginate polysaccharide fiber gel (HA/APFG putty) and autologous bone marrow aspirate (BMA). The hypothesis was that the HA/APFG putty would be as osteoconductive as granular HA and that the presence of BMA would further enhance bone formation in an ovine femoral condyle critical defect model. Thirty-six defects were created and either (1) porous HA granules, (2) HA/APFG putty, or (3) HA/APFG putty + BMA were implanted. After retrieval at 6 and 12 weeks, image analysis techniques were used to quantify bone apposition rates, new bone area, bone-HA scaffold contact, and implant resorption. At 6 weeks postsurgery, significantly lower bone apposition rates were observed in the HA/APFG putty group when compared to the HA (p = 0.014) and HA/APFG putty + BMA (p = 0.014) groups. At 12 weeks, significantly increased amounts of new bone formation were measured within the HA scaffold (33.56 ± 3.53%) when compared to both the HA/APFG putty (16.69 ± 2.7%; p = 0.043) and the defects containing HA/APFG putty + BMA (19.31 ± 3.8%; p = 0.043). The use of an APFG gel as a carrier for injectable CaP bone substitute materials delayed bone formation in this model compared to HA granules alone which enhanced bone formation especially within the interconnected smaller pores. Our results also showed that the addition of autologous BMA did not further enhance its osteoconductive properties. Further study is required to optimize the degradation rate of this APFG binding agent before using as a directly injectable material for repair of bone defect. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2015

Bone formation on calcium phosphate bone substitute materials.

A large number of bone substitute materials are available; for which some authors claim osteoconductivity and some osteoinductivity. In order to rank these materials an in vivo analysis was carried out. These materials were chosen based on their availability and claimed mode of action. Silicon substituted Hydroxyapatite (SiHA), Hydroxyapatite (HA), Resorbable Calcium Phosphate Silicon, Skelite [siliconstabilized tricalcium phosphate-based bone substitute], Pro Osteon 500R [coralline HA], BiIonic [Yttrium stabilized SiHA] and two non-calcium phosphate, Dimeneralised Bone Matrix (DBM) based biomaterials: Accell Connexus DBM putty and Grafton crunch DBM were implanted in sheep femoral condyle defects for 6 weeks. Implanted calcium phosphate (CaP) based biomaterials demonstrated superior bone formation in comparison with the DBM samples. Silicon within CaPs increased the rate of bone formation in vivo. Silicon substituted HA showed increased proliferation rate (P<0.05) of human marrow stromal cells compared to pure HA in vitro. Expression of osteoblastic marker genes RUNX2, Osterix and Osteopontin within the hMSCs indicated the differentiation of preosteoblasts into osteoblasts, and osteogenic development on both HA and SiHA. Expression of osteocalcin and bone sialoprotein genes on HA and SiHA samples indicated the activation of mineralisation process. Differentiation of hMSCs into osteoblasts in vitro suggested a role in promotion of osteoinduction by both HA and SiHA. Implantation of porous SiHA and HA in paraspinous muscle of sheep, exhibited new bone formation through osteoinduction. SiHA indicated significantly higher new bone formation (P<0.01) compared to HA. SiHA and HA biomaterials with higher strut porosity (30%) indicated greater bone formation (P<0.05). In conclusion, CaP based biomaterials demonstrate superior bone formation in comparison with DBM biomaterials. Silicon substitution within HA enhances the cellular activity of hMSCs. Osteoinduction was greatest on SiHA with higher strut porosity. This result is believed to be due to a combination of the effect of interconnected porosity and chemical composition of the bone substitute.

Customer Retention Based on the Number of Purchase: A Data Mining Approach

ABSTRACT Purpose: this paper aimed at finding the relationship between the numbers of purchase and the customer&apos;s income. The data mining tools were applied in the study to find those customers who bought more than one life insurance policy and represented the signs of good payments at the same time. Design/ methodology/ approach: in the present research the data mining tools were employed based on CRISP-DM methodology. The K-means algorithm was used for classification and the prediction was based on a proposed formula in Excel worksheet. Findings: the researcher extracted some simple rules to predict customers&apos; clusters through selecting the customers who bought more than one policy and filtering the income-bringer customers as the companies would be able to use this prediction to change their strategies in relation to different customers. Originality/value: Utilizing data mining tools to classify different customers in life insurance and prediction based on the classification were new approaches of the study. There was not enough research and implementation in relation to the CRM and data mining in the insurance industry in Iran. Especially CRISP-DM methodology was not used extensively enough in a life insurance investigation

Botulinum neurotoxin formulations: overcoming the confusion [Corrigendum]

Samizadeh S, De Boulle K. Clin Cosmet Investig Dermatol. 2018;11:273&ndash;287.On page 273, Introduction section, line 5, the sentence &ldquo;The human nervous system is susceptible to BoNT-A, B, C, E, F, and G and unaffected by D.1,4&ndash;6&rdquo; should be changed to &ldquo;The human nervous system is susceptible to BoNT-A, B, C, E, F, and G and almost unaffected by D.1,4&ndash;6,131&rdquo;. On page 273, Introduction section, line 11, &ldquo;BoNTs&rdquo; should be changed to &ldquo;botulinum toxins&rdquo;. On page 276, Table 2, Storage conditions column, &ldquo;Below 8&deg;C&rdquo; should be changed to &ldquo;2&deg;C&ndash;8&deg;C&rdquo;. &nbsp;Read the original articl