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Purpose: To evaluate the effectiveness of CO3Ap granules in the mandibular bone defects by using computed tomography (CT) images. Methods: This study was retrospective case series of mandibular bone defect reconstruction using CO3Ap granules. Six patients with jawbone cysts treated by simultaneous grafting CO3Ap granules after cyst enucleation were enrolled. Patients without grafting CO3Ap granules were excluded. Mandibular bone height including buccolingual bone height, the change of perpendicular distance between the buccolingual line to the alveolar ridge, and the three-dimensional volume of remaining CO3Ap granules were analyzed using CT images obtained at 3, 6, 12, 18, and 24 months postoperatively. Results: Postoperative CT images showed that cortical and cancellous bone-like structures were formed on the grafting area periphery and inside the defect, respectively, with gradual resorption of the CO3Ap granules. Furthermore, there was no evidence of leaving bone defect even at the center of the lesion when the defect was successfully reconstructed by filling it with CO3Ap granules. The percentage volume of remaining CO3Ap granules to the volume at 3 months postoperatively were 76.1 ± 13.1%, 35.8 ± 22.5%, 25.0 ± 13.0%, and 9.9 ± 6.4% at 6, 12, 18, and 24 months postoperatively, and the volume reduction rate increased significantly within 12 months postoperatively. Conclusion: Grafting CO3Ap granules after the enucleation of a jawbone cyst is a good reconstructive treatment option for postoperative prosthetic treatment because CO3Ap granules are gradually replaced by new bone while preserving the contour of the mandibular bone. Clinical trial number: Not applicable. [ABSTRACT FROM AUTHOR]

Background Artemisinin-resistant Plasmodium falciparum is spreading in Southeast Asia and Africa. In vivo susceptibility to artemisinin is studied by looking at the rate of decline of peripheral parasitemia (parasite clearance half-life). However, parasites that are adhered/sequestered to the endothelium and undetectable in the peripheral blood are not considered in the estimation of parasite clearance. Here, we evaluated the influence of sequestration on in vivo artemisinin efficacy in Uganda, where artemisinin resistance is spreading. Methods We analyzed 133 patients with P. falciparum malaria included in an in vivo study on artemisinin efficacy in northern Uganda in 2018 and 2019. The parasite clearance half-life was estimated from peripheral parasitemia after artemisinin monotherapy. P. falciparum histidine-rich protein 2 (PfHRP2) was measured in pretreatment plasma. The number of sequestered parasites was estimated from PfHRP2 concentration and peripheral parasitemia. Results The estimated number of sequestered parasites per plasma volume ranged from 0 to 2 564 000/μL. Inflammation, thrombocytopenia, and dyslipidemia were significantly associated with sequestration independent of peripheral parasitemia. The median parasite clearance half-lives were 1.65 hours in patients infected with Pfkelch13 wild-type parasites (n = 104) and 3.95 hours in those with A675V artemisinin-resistant mutant (n = 18). In the multivariable model for the wild-type population, 1 000 000/μL of sequestered parasites were estimated to delay parasite clearance by 16.8% (95% confidence interval, 5.1%–28.5%), although it was not clear in the A675V population. Conclusions In patients with P. falciparum malaria without artemisinin-resistant mutations, intensive sequestration delays parasite clearance after treatment, which may contribute to reduced artemisinin efficacy. [ABSTRACT FROM AUTHOR]

Carbonate apatite (CO3Ap) granules are known to show good osteoconductivity and replaced to new bone. On the other hand, it is well known that a porous structure allows bone tissue to penetrate its pores, and the optimal pore size for bone ingrowth is dependent on the composition and structure of the scaffold material. Therefore, the aim of this study was to fabricate various porous CO3Ap granules through a two‐step dissolution–precipitation reaction using CaSO4 as a precursor and 30‐, 50‐, 120‐, and 205‐μm diameter microfibers as porogen and to find the optimal pore size of CO3Ap. Porous CO3Ap granules were successfully fabricated with pore size 8.2–18.7% smaller than the size of the original fiber porogen. Two weeks after the reconstruction of rabbit calvarial bone defects using porous CO3Ap granules, the largest amount of mature bone was seen to be formed inside the pores of CO3Ap (120) [porous CO3Ap granules made using 120‐μm microfiber] followed by CO3Ap (50) and CO3Ap (30). At 4 and 8 weeks, no statistically significant difference was observed based on the pore size, even though largest amount of mature bone was formed in case of CO3Ap (120). It is concluded, therefore, that the optimal pore size of the CO3Ap is that of CO3Ap (120), which is 85 μm. [ABSTRACT FROM AUTHOR]

Beta‐tricalcium phosphate granular cement (β‐TCP GC), consisting of β‐TCP granules and an acidic calcium phosphate (Ca‐P) solution, shows promise in the reconstruction of bone defects as it sets to form interconnected porous structures, that is, β‐TCP granules are bridged with dicalcium phosphate dihydrate (DCPD) crystals. In this study, the effects of acidic Ca‐P solution concentration (0–600 mmol/L) on the setting reaction and tissue response to β‐TCP GC were investigated. The β‐TCP GC set upon mixing with its liquid phase, based on the formation of DCPD crystals, which bridged β‐TCP granules to one another. Diametral tensile strength of the set β‐TCP GC was relatively the same, at ∼0.6 MPa, when the Ca‐P concentration was 20–600 mmol/L. Due to the setting ability, reconstruction of the rat's calvarial bone defect using β‐TCP GC with 20, 200, and 600 mmol/L Ca‐P solution was much easier compared to that with β‐TCP granules without setting ability. Four weeks after the reconstruction, the amount of new bone was the same, ∼17% in both β‐TCP GC and β‐TCP granules groups. Cellular response to β‐TCP granules and β‐TCP GC using the 20 mmol/L acidic Ca‐P solution was almost the same. However, β‐TCP GC using the 200 and 600 mmol/L acidic Ca‐P solution showed a more severe inflammatory reaction. It is concluded, therefore, that β‐TCP GC, using the 20 mmol/L acidic Ca‐P solution, is recommended as this concentration allows surgical techniques to be performed easily and provides good mechanical strength, and the similar cellular response to β‐TCP granules. © 2019 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 108B:22–29, 2020. [ABSTRACT FROM AUTHOR]

Poly(ether ether ketone) (PEEK) has emerged as a candidate to replace metal implants because of its satisfactory mechanical properties, radiolucency, and lack of metal allergy. However, PEEK lacks osseointegration ability limiting its clinical applications. To overcome this problem, we prepared PEEK with a micro-rough surface using the sandblast method to modulate its osseointegration property; the sandblast method is simple, cost-effective, and is already applied to clinical metal implants. The surface roughness of the sandblasted PEEK was about 2.3 µm, whereas that of mirror-polished PEEK was 0.06 µm. Rat bone marrow-derived mesenchymal stem cells (RMSCs) showed higher proliferation, osteocalcin (OC) expression and bone-like nodule formation on micro-roughened PEEK compared with those cultured on mirror-polished PEEK, suggesting that micro-roughening facilitated RMSCs proliferation and differentiation. The micro-roughened surface slightly mitigated secretion of inflammatory C-C motif chemokine 2 (CCL-2) from lipopolysaccharide (LPS)-stimulated macrophages, but not of tumor necrosis factor a (TNFa) and interleukin-6 (IL-6). Finally, to compare osseointegration, specimens were implanted in rat femur bone marrow cavities, and then the pull-out force was measured. The pull-out force of micro-roughened PEEK was about four times higher than that of the mirror-polished PEEK. These results showed that micro-roughening of PEEK using the sandblast method was able to improve osseointegration, partly through elevating proliferation and differentiation of RMSCs. [ABSTRACT FROM AUTHOR]

Bone defect reconstruction would be greatly improved if β-tricalcium phosphate (β-TCP) granules had the ability to self-set without sacrificing their osteoconductivity potential. This study aimed to identify a method to permit β-TCP self-setting whilst maintaining good osteoconductivity. When mixed with acidic calcium phosphate solution, β-TCP granules were found to readily set, forming a fully interconnected porous structure. On mixing, dicalcium phosphate dihydrate crystals formed on the surface of β-TCP granules, bridging the granules and resulting in the setting reaction. The setting time of the β-TCP granular cement (β-TCP GC) was approximately 1 min and its mechanical strength, in terms of diametral tensile strength, was approximately 0.8 MPa. The β-TCP GC and β-TCP granules both showed the same level of osteoconductivity within rat calvaria bone defects. At 2 and 4 weeks post-implantation, new bone formation was comparable between the two β-TCP based bone substitutes. We conclude that β-TCP GC has excellent potential for use as a cement in bone defect reconstruction. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 800-807, 2018. [ABSTRACT FROM AUTHOR]