HDAC1/2-Dependent P0 Expression Maintains Paranodal and Nodal Integrity Independently of Myelin Stability through Interactions with Neurofascins.

The pathogenesis of peripheral neuropathies in adults is linked to maintenance mechanisms that are not well understood. Here, we elucidate a novel critical maintenance mechanism for Schwann cell (SC)-axon interaction. Using mouse genetics, ablation of the transcriptional regulators histone deacetylases 1 and 2 (HDAC1/2) in adult SCs severely affected paranodal and nodal integrity and led to demyelination/remyelination. Expression levels of the HDAC1/2 target gene myelin protein zero (P0) were reduced by half, accompanied by altered localization and stability of neurofascin (NFasc)155, NFasc186, and loss of Caspr and septate-like junctions. We identify P0 as a novel binding partner of NFasc155 and NFasc186, both in vivo and by in vitro adhesion assay. Furthermore, we demonstrate that HDAC1/2-dependent P0 expression is crucial for the maintenance of paranodal/nodal integrity and axonal function through interaction of P0 with neurofascins. In addition, we show that the latter mechanism is impaired by some P0 mutations that lead to late onset Charcot-Marie-Tooth disease.

Osteoarticular vascular corrosion casting using industrial polyurethane for the 3D representation of the vascular tree on human knee.

Vascular casting is a widely used method for the representation of body vascularization. Many different injection materials have been described throughout the time to enhance the arterial vascular supply within a specifically defined anatomical location. The use of industrial polyurethane has been recently evaluated and applied to animal and human anatomy. The aim of this study was to confirm the safe and reliable use of industrial polyurethane in knee specimen in order to obtain a three-dimensional vascular tree of the distal femur. 10 fresh-frozen knees (mid-thigh to mid tibia) were used to assess the vascularity around the femoral condyles. Industrial polyurethane foam (Soudal™ foam) was diluted with acetone in order to obtain a runny fluid, easy to inject. After injection, the knees were bathed in a 10% NaOH solution, heated at 30°. The corrosion process took from 20 to 24h and allowed all the soft tissue surrounding the knee to be subsided, leaving only the bone with polyurethane vascular architecture. After soft tissue corrosion, the vascular network around the knees was easily identified underlying the relation of the vessels to the bone. Even small arterioles (diameter<1mm) were distinguished with a good resistance to breakage. Corrosion casting remains an easy and reliable alternative to dissection for the understanding of tissue perfusion as the handling of the polyurethane is easy and has low costs. The described author's method can be used osteo-articular specimen as well as in other organs. The protocol of injection and corrosion needs however to be adapted to the different specimen and anatomical location. Polyurethane associated to acetone can safely be used as injection material in order to demonstrate the vascularity of a specimen and remains easy to use.

Culture and differentiation of osteoblasts on coral scaffold from human bone marrow mesenchymal stem cells.

In this paper we describe an approach that aims to provide fundamental information towards a scientific, biomechanical basis for the use of natural coral scaffolds to initiate mesenchymal stem cells into osteogenic differentiation for transplant purposes. Biomaterial, such as corals, is an osteoconductive material that can be used to home human derived stem cells for clinical regenerative purposes. In bone transplantation, the use of biomaterials may be a solution to bypass two main critical obstacles, the shortage of donor sites for autografts and the risk of rejection with allograft procedures. Bone regeneration is often needed for multiple clinical purposes for instance, in aesthetic reconstruction and regenerative procedures. Coral graft Porites lutea has been used by our team for a decade in clinical applications on over a thousand patients with different bone pathologies including spinal stenosis and mandibular reconstruction. It is well accepted that human bone marrow (hBM) is an exceptional source of mesenchymal stem cells (MSCs), which may differentiate into different cell phenotypes such as osteoblasts, chondrocytes, adipocytes, myocytes, cardiomyocytes and neurons. Isolated MSCs from human bone marrow were induced into osteoblasts using an osteogenic medium enriched with two specific growth factors, FGF9 and vitamin D2. Part of the cultured MSCs were directly transferred and seeded onto coral scaffolds (Porites Lutea) and induced to differentiate into osteoblasts and part were cultured in flasks for osteocell culture. The data support the concept that hBM is a reliable source of MSCs which may be easily differentiated into osteoblasts and seeded into coral as an optimal device for clinical application. Within this project we have also discussed the biological nature of MSCs, their potential application for clinical transplantation and the prospect of their use in gene therapy.

Experience from an optional dissection course in a clinically-orientated concept to complement system-based anatomy in a reformed curriculum.

Profound anatomical knowledge is the basis for modern demands in medicine and surgery, but many countries worldwide including Australia and New Zealand have discontinued offering dissection courses to medical and dental students during the past decades. This educational project done in Australia aimed at enhancing basic and advanced anatomy teaching by engaging a sub-group of second-year undergraduate students of a compulsory prosection- and model-based anatomy course (n = 54/170) in an optional multimodal course, which should easily articulate with a vertical curriculum. With topographical cadaver dissections as core, peer student-teams prepared and peer-assessed anatomy lectures based on clinical topics, which were rated highly by the peers and teachers. Anatomical knowledge was tested by quizzes and a multiple-choice examination. Individual dissection skills were self- and teacher-assessed. A final course grade was assigned based on these assessments. The grades in the system-based compulsory course achieved by the attendees of the paralleling dissection course were compared with their peers attending other optional courses. After beginning of the semester, the students in the dissection course performed similar, significantly (P < 0.005) improved during the semester (78.5% vs. 69.9%, 70.1% vs. 64.1%), but in the integrated (including anatomy, biochemistry, physiology) final examination at the end of the year only tended to higher scores. As assessed through interviews and a voluntary questionnaire, all students of the optional dissection course liked these activities, which enhanced their learning experience. Thus, this concept elegantly integrates anatomical dissection with modern teaching demands and is feasible for implementation in modernized curricula. Anat Sci Educ 11: 32-43. © 2017 American Association of Anatomists.

Microfluidic fabrication of cationic curcumin nanoparticles as an anti-cancer agent.

Curcumin nanoparticles of less than 50 nm in diameter are accessible using a continuous flow microfluidic rotating tube processor (RTP) under scalable conditions, at room temperature. A mixture of DDAB and Pluronic F127 renders higher stability of the curcumin nanoparticles in physiological pH 7.4 for up to eight hours. The nanoparticles have enhanced cytotoxicity in estrogens receptor negative and positive breast cancer cell lines compared with free curcumin.

Bio-corrosion of stainless steel by osteoclasts--in vitro evidence.

Most metals in contact with biological systems undergo corrosion by an electrochemical process. This study investigated whether human osteoclasts (OC) are able to grow on stainless steel (SS) and directly corrode the metal alloy leading to the formation of corresponding metal ions, which may cause inflammatory reactions and activate the immune system. Scanning electron microscopy analysis demonstrated long-term viable OC cultures and evident resorption features on the surface of SS discs on which OC were cultured for 21 days. The findings were confirmed by atomic emission spectrometry investigations showing significantly increased levels of chromium, nickel, and manganese in the supernatant of OC cultures. Furthermore, significant levels of pro-inflammatory cytokines IL-1beta, IL-6, and TNF-alpha, which are considered to be major mediators of osteolysis, were revealed in the same cultures by cytometric bead array analysis. Within the present study, it was shown that human osteoclast precursors are able to grow and differentiate towards mature OC on SS. The mature cells are able to directly corrode the metal surface and release corresponding metal ions, which induce the secretion of pro-inflammatory cytokines that are known to enhance osteoclast differentiation, activation, and survival. Enhanced corrosion and the subsequently released metal ions may therefore result in enhanced osteolytic lesions in the peri-prosthetic bone, contributing to the aseptic loosening of the implant.

Titanium IV ions induced human osteoclast differentiation and enhanced bone resorption in vitro.

There is increasing evidence that titanium (Ti) ions are released from orthopedic implants, with concentrations in the range of 1 microM in tissue and blood, and may play a role in aseptic loosening of orthopedic implants. This study investigated whether Ti(IV) ions induce differentiation of monocytic osteoclast precursors into osteo-resorptive multinucleated cells and influence the activation and function of in vitro generated osteoclasts. Human monocytes and in vitro generated osteoclasts were exposed to 1 microM Ti(IV) ions for 10 days. Thereafter, osteoclast differentiation, activation, and function were evaluated. Transcription of specific osteoclastic genes was measured using quantitative reverse transcription polymerase chain reactions, which showed increased expression of tartrate-resistant acid phosphatase (TRAP) in approximately 20% of Ti(IV)-treated monocytes. Detection and quantification of intracellular TRAP activity using ELF97 as a fluorescent substrate revealed a significant increase of TRAP-positive cells in Ti(IV)-treated monocytes. Additionally, as demonstrated on dentin slide cultures, Ti(IV)-treated monocytes became functional bone resorbing cells, significantly increasing their osteo-resorptive activity to similar levels as osteoclasts in vitro. These results suggest that Ti(IV) ions released by biocorrosion from orthopedic implants induce differentiation of monocytes toward mature, functional osteoclasts, which may well contribute the pathomechanism of aseptic loosening.