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Abstract: The objective of the current study is to prepare a biomimetic collagen–apatite scaffold for improved bone repair and regeneration. A novel bottom–up approach has been developed, which combines a biomimetic self-assembly method with a controllable freeze-casting technology. In this study, the mineralized collagen fibers were generated using a simple one-step co-precipitation method which involved collagen self-assembly and in situ apatite precipitation in a collagen-containing modified simulated body fluid (m-SBF). The precipitates were then subjected to controllable freeze casting, forming scaffolds with either an isotropic equiaxed structure or a unidirectional lamellar structure. These scaffolds were comprised of collagen fibers and poorly crystalline bone-like carbonated apatite nanoparticles. The mineral content in the scaffold could be tailored in the range 0–54wt.% by simply adjusting the collagen content in the m-SBF. Further, the mechanisms of the formation of both the equiaxed and the lamellar scaffolds were investigated, and freezing regimes for equiaxed and lamellar solidification were established. Finally, the bone-forming capability of such prepared scaffolds was evaluated in vivo in a mouse calvarial defect model. It was confirmed that the scaffolds well support new bone formation. [Copyright &y& Elsevier]

Objective: The purpose of this study was to evaluate patients undergoing elective repair of infrarenal abdominal aortic aneurysms (AAAs) and the longitudinal trends in surgical management (open repair vs endovascular aneurysm repair [EVAR]), factors associated with the choice of surgical technique, and differences in the rate of in-hospital mortality at a single large-volume Canadian center. Methods: This retrospective cohort study used data from a prospectively collected vascular surgery database and reviewed all patients undergoing elective repair of an infrarenal AAA over a recent 10-year period (June 2000-May 2010). Information was reviewed regarding surgical techniques, patient demographics, and short-term outcomes. Subsequent analysis included univariate statistics and multivariable logistic regression with data presented as odds ratios (ORs) and 95% confidence intervals (CIs). Results: A total of 1942 patients underwent elective AAA repair over this 10-year study period, 1067 (54.9%) via open repair and 875 (45.1%) via EVAR. The proportion of patients undergoing EVAR was significantly higher in the latter half of the study period compared to the first half (55.8% vs 33.9%; P < .01). Older patients (75 vs 71; P < .01) and those with higher American Society of Anesthesiologists classifications (P < .01) were more likely to receive endovascular repair than open repair. The overall in-hospital mortality rate in the entire cohort was low (2.3% for EVAR and 3.9% for open repair), and after multivariable logistic regression and adjustment for preoperative factors, in-hospital mortality was significantly higher in patients with open AAA repair (OR, 1.8; 95% CI, 1.04-3.13; P = .04). Conclusions: This 10-year analysis shows a significant shift toward an endovascular approach in the repair of infrarenal AAAs at our Canadian center. Similar to other jurisdictions, higher risk and older patients are more likely to be treated with an endovascular repair resulting in a survival advantage in these patients compared to standard open repair. [Copyright &y& Elsevier]

Background: Traditional limitations of cardiac CT are related to image noise, blooming artifacts from calcifications and stents, and radiation exposure. We evaluated whether these limitations can be ameliorated by the use of iterative reconstruction in image space (IRIS) instead of traditional filtered back projection (FBP) image reconstruction techniques. Methods: We compared image reconstruction with the use of IRIS with traditional FBP for their effect on image quality, noise, volume of heavy coronary artery calcifications, and stents as a measure of “blooming” artifacts, and radiation dose at cardiac CT. The radiation dose comparison was performed as a matched pair analysis, whereas all other comparisons were performed within the same group of patients. Results: The subjective image quality of IRIS reconstructions was rated higher than FBP reconstructions. Image noise was lower with IRIS than with FBP. The volume of stents and heavy coronary artery calcifications measured lower in IRIS reconstructed series compared with FBP. Similar levels of image noise were achieved with 80/100 kVp of tube voltage with IRIS compared with 120 kVp and FBP, resulting in a 62% reduction in effective dose. Conclusion: Our preliminary experiences suggest that IRIS incrementally improves the CT evaluation of coronary arteries, especially in challenging scenarios. Substantial radiation reduction seems feasible without associated increases in image noise. [ABSTRACT FROM AUTHOR]