Polycaprolactone Microfibrous Scaffolds to Navigate Neural Stem Cells

Fibrous scaffolds have shown promise in tissue engineering due to their ability to improve cell alignment and migration. In this paper, poly(ε-caprolactone) (PCL) fibers are fabricated in different sizes using a microfluidic platform. By using this approach, we demonstrated considerable flexibility in ability to control the size of the fibers. It was shown that the average diameter of the fibers was obtained in the range of 2.6–36.5 μm by selecting the PCL solution flow rate from 1 to 5 μL min–1 and the sheath flow rate from 20 to 400 μL min–1 in the microfluidic channel. The microfibers were used to create 3D microenvironments in order to investigate growth and differentiation of adult hippocampal stem/progenitor cells (AHPCs) in vitro. The results indicated that the 3D topography of the PCL substrates, along with chemical (extracellular matrix) guidance cues supported the adhesion, survival, and differentiation of the AHPCs. Additionally, it was found that the cell deviation angle for 44–66% of cells on different types of fibers was less than 10°. This reveals the functionality of PCL fibrous scaffolds for cell alignment important in applications such as reconnecting serious nerve injuries and guiding the direction of axon growth as well as regenerating blood vessels, tendons, and muscle tissue

Obturating the pink tooth: An in vitro comparative evaluation of different materials

Aim: The aim is to evaluate the obturating potential of thermoplasticized gutta-percha, mineral trioxide aggregate (MTA), and Biodentine in simulated internal resorption cavities. Materials and Methods: Thirty human extracted teeth with single canal and mature apex were collected for the study. Access cavity was prepared in each. For all the teeth, standardized instrumentation was done to apical size of ISO #50 K stainless steel hand file. Following instrumentation, at the length of 6 mm short of working length, internal resorption cavity was simulated using Gates–Glidden drill, as the canal of the selected teeth was wide enough and thus widening of the canal occurred only at the desired working length. The teeth were radiographed to check internal resorption cavity. The teeth were randomly divided into three groups; ten teeth in each group. Samples were obturated as follows: Group 1 – thermoplasticized gutta-percha, Group 2 – MTA, and Group 3 – Biodentine. Samples were stored at room temperature for 48 h. After 48 h, samples were evaluated radiographically and microscopically using Dental Operating Microscope. Statistical analysis of the results was performed using Kruskal–Wallis test. Results: Results obtained were statistically significant. Conclusion: MTA and Biodentine showed better sealing than thermoplasticized gutta-percha

Contrast Enhanced Spectral Mammography:A Review

Contrast-enhanced spectral mammography (CESM) provides low-energy 2D mammographic images comparable to standard digital mammography and a post-contrast recombined image to assess tumor neovascularity similar to magnetic resonance imaging (MRI). The utilization of CESM in the United States is currently low but could increase rapidly given many potential indications for clinical use. This article discusses historical background and literature review of indications and diagnostic accuracy of CESM to date. CESM is a growing technique for breast cancer detection and diagnosis that has levels of sensitivity and specificity on par with contrast-enhanced breast MRI. Because of its similar performance and ease of implementation, CESM is being adopted for multiple indications previously reserved for MRI, such as problem-solving, disease extent in newly diagnosed patients, and evaluating the treatment response of neoadjuvant chemotherapy. (C) 2018 Elsevier Inc. All rights reserved

Heterogeneity in Intratumoral Regions with Rapid Gadolinium Washout Correlates with Estrogen Receptor Status and Nodal Metastasis

Purpose: To evaluate heterogeneity within tumor subregions or “habitats” via textural kinetic analysis on breast dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) for the classification of two clinical prognostic features; 1) estrogen receptor (ER)-positive from ER-negative tumors, and 2) tumors with four or more viable lymph node metastases after neoadjuvant chemotherapy from tumors without nodal metastases. Materials and Methods: Two separate volumetric DCE-MRI datasets were obtained at 1.5T, comprised of bilateral axial dynamic 3D T1-weighted fat suppressed gradient recalled echo-pulse sequences obtained before and after gadolinium-based contrast administration. Representative image slices of breast tumors from 38 and 34 patients were used for ER status and lymph node classification, respectively. Four tumor habitats were defined based on their kinetic contrast enhancement characteristics. The heterogeneity within each habitat was quantified using textural kinetic features, which were evaluated using two feature selectors and three classifiers. Results: Textural kinetic features from the habitat with rapid delayed washout yielded classification accuracies of 84.44% (area under the curve [AUC] 0.83) for ER and 88.89% (AUC 0.88) for lymph node status. The texture feature, information measure of correlation, most often chosen in cross-validations, measures heterogeneity and provides accuracy approximately the same as with the best feature set. Conclusion: Heterogeneity within habitats with rapid washout is highly predictive of molecular tumor characteristics and clinical behavior. J. Magn. Reson. Imaging 2015;42:1421–1430