The Effectiveness of Collaborative Augmented Reality in Gross Anatomy Teaching: A Quantitative and Qualitative Pilot Study.

In the context of gross anatomy education, novel augmented reality (AR) systems have the potential to serve as complementary pedagogical tools and facilitate interactive, student-centered learning. However, there is a lack of AR systems that enable multiple students to engage in collaborative, team-based learning environments. This article presents the results of a pilot study in which first-year medical students (n = 16) had the opportunity to work with such a collaborative AR system during a full-day gross anatomy seminar. Student performance in an anatomy knowledge test, conducted after an extensive group learning session, increased significantly compared to a pre-test in both the experimental group working with the collaborative AR system (P < 0.01) and in the control group working with traditional anatomy atlases and three-dimensional (3D) models (P < 0.01). However, no significant differences were found between the test results of both groups. While the experienced mental effort during the collaborative learning session was considered rather high (5.13 ± 2.45 on a seven-point Likert scale), both qualitative and quantitative feedback during a survey as well as the results of a System Usability Scale (SUS) questionnaire (80.00 ± 13.90) outlined the potential of the collaborative AR system for increasing students' 3D understanding of topographic anatomy and its advantages over comparable AR systems for single-user experiences. Overall, these outcomes show that collaborative AR systems such as the one evaluated within this work stimulate interactive, student-centered learning in teams and have the potential to become an integral part of a modern, multi-modal anatomy curriculum.

The effects of crosslinkers on physical, mechanical, and cytotoxic properties of gelatin sponge prepared via in-situ gas foaming method as a tissue engineering scaffold.

In this study porous gelatin scaffolds were prepared using in-situ gas foaming, and four crosslinking agents were used to determine a biocompatible and effective crosslinker that is suitable for such a method. Crosslinkers used in this study included: hexamethylene diisocyanate (HMDI), poly(ethylene glycol) diglycidyl ether (epoxy), glutaraldehyde (GTA), and genipin. The prepared porous structures were analyzed using Fourier Transform Infrared Spectroscopy (FT-IR), thermal and mechanical analysis as well as water absorption analysis. The microstructures of the prepared samples were analyzed using Scanning Electron Microscopy (SEM). The effects of the crosslinking agents were studied on the cytotoxicity of the porous structure indirectly using MTT analysis. The affinity of L929 mouse fibroblast cells for attachment on the scaffold surfaces was investigated by direct cell seeding and DAPI-staining technique. It was shown that while all of the studied crosslinking agents were capable of stabilizing prepared gelatin scaffolds, there are noticeable differences among physical and mechanical properties of samples based on the crosslinker type. Epoxy-crosslinked scaffolds showed a higher capacity for water absorption and more uniform microstructures than the rest of crosslinked samples, whereas genipin and GTA-crosslinked scaffolds demonstrated higher mechanical strength. Cytotoxicity analysis showed the superior biocompatibility of the naturally occurring genipin in comparison with other synthetic crosslinking agents, in particular relative to GTA-crosslinked samples.

Gelatin porous scaffolds fabricated using a modified gas foaming technique: characterisation and cytotoxicity assessment.

The current study presents an effective and simple strategy to obtain stable porous scaffolds from gelatin via a gas foaming method. The technique exploits the intrinsic foaming ability of gelatin in the presence of CO2 to obtain a porous structure stabilised with glutaraldehyde. The produced scaffolds were characterised using physical and mechanical characterisation methods. The results showed that gas foaming may allow the tailoring of the 3-dimensional structure of the scaffolds with an interconnected porous structure. To assess the effectiveness of the preparation method in mitigating the potential cytotoxicity risk of using glutaraldehyde as a crosslinker, direct and in-direct cytotoxicity assays were performed at different concentrations of glutaraldehyde. The results indicate the potential of the gas foaming method, in the preparation of viable tissue engineering scaffolds.

Mitochondrial Respiration Is Decreased in Rat Kidney Following Fetal Exposure to a MaternalLow-ProteinDiet.

Maternal protein restriction in rat pregnancy is associated with impaired renal development and age-related loss of renal function in the resulting offspring. Pregnant rats were fed either control or low-protein (LP) diets, and kidneys from their male offspring were collected at 4, 13, or 16 weeks of age. Mitochondrial state 3 and state 4 respiratory rates were decreased by a third in the LP exposed adults. The reduction in mitochondrial function was not explained by complex IV deficiency or altered expression of the complex I subunits that are typically associated with mitochondrial dysfunction. Similarly, there was no evidence that LP-exposure resulted in greater oxidative damage to the kidney, differential expression of ATP synthetase ß-subunit, and ATP-ADP translocase 1. mRNA expression of uncoupling protein 2 was increased in adult rats exposed to LP in utero, but there was no evidence of differential expression at the protein level. Exposure to maternal undernutrition is associated with a decrease in mitochondrial respiration in kidneys of adult rats. In the absence of gross disturbances in respiratory chain protein expression, programming of coupling efficiency may explain the long-term impact of the maternal diet.

An interaction between two RNA binding proteins, Nab2 and Pub1, links mRNA processing/export and mRNA stability.

mRNA stability is modulated by elements in the mRNA transcript and their cognate RNA binding proteins. Poly(U) binding protein 1 (Pub1) is a cytoplasmic Saccharomyces cerevisiae mRNA binding protein that stabilizes transcripts containing AU-rich elements (AREs) or stabilizer elements (STEs). In a yeast two-hybrid screen, we identified nuclear poly(A) binding protein 2 (Nab2) as being a Pub1-interacting protein. Nab2 is an essential nucleocytoplasmic shuttling mRNA binding protein that regulates poly(A) tail length and mRNA export. The interaction between Pub1 and Nab2 was confirmed by copurification and in vitro binding assays. The interaction is mediated by the Nab2 zinc finger domain. Analysis of the functional link between these proteins reveals that Nab2, like Pub1, can modulate the stability of specific mRNA transcripts. The half-life of the RPS16B transcript, an ARE-like sequence-containing Pub1 target, is decreased in both nab2-1 and nab2-67 mutants. In contrast, GCN4, an STE-containing Pub1 target, is not affected. Similar results were obtained for other ARE- and STE-containing Pub1 target transcripts. Further analysis reveals that the ARE-like sequence is necessary for Nab2-mediated transcript stabilization. These results suggest that Nab2 functions together with Pub1 to modulate mRNA stability and strengthen a model where nuclear events are coupled to the control of mRNA turnover in the cytoplasm.

Oxidative inactivation of paraoxonase--implications in diabetes mellitus and atherosclerosis.

Human serum paraoxonase (PON1) has been implicated to play an important role in cardiovascular disease and diabetes. Studies in the literature indicate that PON1 has two different enzyme activities, i.e., esterase and hydroperoxide reducing activities. The objective of this study was to establish the importance of these two activities and to distinguish between them. As the addition of copper immediately inactivated the enzyme, we used auto-oxidation as the model system. Auto-oxidation of HDL resulted in more than 80% reduction of the esterolytic activity, which was protected by antioxidants, Vitamin E (50%) and PDTC (95%) and completely by 1 M glucose. In contrast, the hydroperoxide reducing activity, using unesterified hydroperoxides remained unaffected with time. We also used pNPHPODE (novel substrate) to establish that hydrolysis might be a prerequisite for the enzyme to act on the esterified hydroperoxide. The results indicated that the hydrolysis of the substrate was inhibited under oxidizing conditions with no reduction of the hydroperoxide. Overall, our findings suggest that protecting the esterolytic activity of PON1 by antioxidants might be important in preserving its action on phospholipid peroxides and a concerted reaction involving the esterolytic and hydroperoxide reducing activities might be suggested for the action of PON1.

Comparison of debridement versus suture in large rotator cuff tears: long-term study of 64 shoulders.

INTRODUCTION: The goal of this study is to determine whether suturing is superior to non-closure in terms of the subjective long-term outcome in large rotator cuff tears. MATERIALS AND METHODS: A total of 64 shoulders with rotator cuff tears of at least 3 cm diameter and followed up for a mean period of 5 years and 8 months were retrospectively examined. The patients' medical history, clinical findings, radiographs and Constant scores were studied. Patients whose tears had been closed with an open suture (n=33) were compared with those whose tears had not been closed (n=31). RESULTS: Neither the comparison between open suturing and debridement nor that between open and arthroscopic debridement reveal a significant difference with regard to the overall Constant score or the individual parameters. CONCLUSION: These results suggest that in the long-term, suturing of large rotator cuff tears is not superior to debridement.

Biology and biomechanics.

Increased participation by the general population in athletic activities leads to increased trauma to bones, joint surfaces, and soft tissues. Management and treatment of these injuries has significantly improved over the past few decades. The application of knowledge gained from basic science research in biology and biomechanics has continuously contributed to that. Biological advances have been made in the field of gene therapy, cell therapy, and tissue engineering. Certainly, the greatest focus is bone and cartilage research that will lead to improved fracture repair in the traumatic injured population, as well as prevention of early osteoarthritic changes in the injured athletic population. In biomechanical research, contributions have been made to further understand kinematic behavior of joints that will lead to improved ligament reconstruction techniques and rehabilitation regimens. Various fixation techniques and several different ligament reconstruction techniques have been studied and validated. In the future, improved understanding of ligament healing, graft incorporation, and revascularization will lead to improved outcome of surgical reconstruction techniques in orthopaedic sports medicine. Exciting research has been performed over the past years and will be reviewed in this article.