Electron beam melting (EBM) is a three-dimensional (3D) printing technique for the production of metal structures where complex geometries with interconnected porosities can be built. Incorporation of as little as 0.04% Zr into the CoCr alloy can significantly improve the biomechanical anchorage of constructs fabricated by EBM. Here we investigate bone material properties, including microstructure and composition, adjacent to 3D printed CoCr implants with and without addition of 0.04% Zr, after 8 weeks of healing in the rabbit femur. In low amounts, zirconium addition does not alter the microstructure and extracellular matrix composition of bone formed adjacent to the surface of EBM manufactured implants. Bone ingrowth into surface irregularities of 3D printed CoCr and CoCr + Zr implants is seen. Extensive remodeling is also evident. Osteocytes attach directly on to the implant surface. The interfacial tissue at CoCr and CoCr + Zr has similar mineral crystallinity, apatite-to-collagen ratio, carbonate-to-phosphate ratio, Ca/P ratio, bone-implant contact, percentage porosity, and osteocyte density (N.Ot/B.Ar). Compared to the native bone, the mineral crystallinity of the interfacial tissue was lower while N.Ot/B.Ar was higher for both CoCr and CoCr + Zr. Overall, the results indicate that bone tissue adjacent to CoCr and CoCr + Zr implants is highly mature and exhibits comparable healing kinetics. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1655-1663, 2018.
Background: The preoperative prediction of whether melanomas are invasive or in situ can influence initial management. Objectives: This study evaluated the accuracy rate, interobserver concordance, sensitivity and specificity in determining if a melanoma is invasive or in situ, as well as the ability to predict invasive melanoma thickness based on clinical and dermoscopic images. Methods: In this retrospective, single-center investigation, 7 dermatologists independently reviewed clinical and dermoscopic images of melanomas to predict if they were invasive or in situ and, if invasive, their Breslow thickness. Fleiss’ and Cohen’s kappa (κ) were used for interobserver concordance and agreement with histopathological diagnosis. Results: We included 184 melanomas (110 invasive and 74 in situ). Diagnostic accuracy ranged from 67.4% to 76.1%. Accuracy rates for in situ and invasive melanomas were 57.5% (95% confidence interval [CI], 53.1%-61.8%) and 81.7% (95% CI, 78.8%-84.4%), respectively. Interobserver concordance was moderate (κ = 0.47; 95% CI, 0.44-0.51). Sensitivity for predicting invasiveness ranged from 63.6% to 91.8% for 7 observers, while specificity was 32.4%-82.4%. For all correctly predicted invasive melanomas, agreement between predictions and correct thickness over or under 1.0 mm was moderate (κ = 0.52; 95% CI, 0.45-0.58). All invasive melanomas incorrectly predicted by any observer as in situ had a thickness <1.0 mm. All 32 melanomas >1.0 mm were correctly predicted to be invasive by all observers. Conclusions: Accuracy rates for predicting thick melanomas were excellent, melanomas inaccurately predicted as in situ were all thin, and interobserver concordance for predicting in situ or invasive melanomas was moderate. Preoperative dermoscopy of suspected melanomas is recommended for choosing appropriate surgical margins.
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