Role of interfibrillar proteoglycans in tendon elastic recoil

Force transmission and elastic recoil in tendon are related to fibre and fibrillar crimps. Tendon fibrils arrange in a network system in which forces are also laterally transferred between neighbouring fibrils through interfibrillar proteoglycans. The interfibrillar proteoglycan decorin with a dermatansulphate chain (DS) represents the 90% of tendon proteoglycans and seems to transfer forces between fibrils during tendon stretching. DS  in decorin and biglycan may also play a role in packing fibrils forming crimps. Aim of this study was to investigate whether decorin and biglycan DS affects the microstructure/function of fibrillar crimps in tendon elastic recoil. Four relaxed Achilles tendons of 8 rats (group I) were immediately immersed for 6 hours in Chondroitinase-B solution, fixed, dehydrated and prepared for SEM. Other 4 tendons (group II) were fixed in a clamp, stretched 5 - 6 % in Chondroitinase-B solution, fixed in Karnovsky solution under stretching and processed as group I. Other 4 tendons (group III) were clamped, stretched in Chondroitinase-B solution for 6 hours, removed from the clamps to allow relaxation, fixed and processed as above. Other 4 tendons (group IV) were immersed in  saline solution and mechanically disrupted to obtain isolated fibrils for TEM. Both enzymatic and mechanical removal of DS in relaxed tendons of group I and IV didn’t affect the morphology of fibre and fibrillar crimps. All collagen fibrils of group I showed crimped fibres showing particular knots or fibrillar crimps at the top of each fibre crimp: fibrils twisted leftwards first, changing their plane of running, and then sharply bent, changing their course on the new plane. Stretched tendons in Chondroitinase-B solution (group II) showed flattened crimps but regular fibrillar crimps were still present. Stretched tendons immersed in Chondroitinase-B solution, relaxed and fixed (group III) showed both regular fibre and fibrillar crimps: a fibril local leftward twisting and bending in the fibrillar crimp regions was observable like in group I. These data demonstrate that structure/function of fibrillar crimps in recoiling fibrils/fibres in tendon does not depend on DS, but seems to be related to the hierarchical alternating handedness of collagen structures

Early Healing Events around Titanium Implant Devices with Different Surface Microtopography: A Pilot Study in an In Vivo Rabbit Model

In the present pilot study, the authors morphologically investigated sandblasted, acid-etched surfaces (SLA) at very early experimental times. The tested devices were titanium plate-like implants with flattened wide lateral sides and jagged narrow sides. Because of these implant shape and placement site, the device gained a firm mechanical stability but the largest portion of the implant surface lacked direct contact with host bone and faced a wide peri-implant space rich in marrow tissue, intentionally created in order to study the interfacial interaction between metal surface and biological microenvironment. The insertion of titanium devices into the proximal tibia elicited a sequence of healing events. Newly formed bone proceeded through an early distance osteogenesis, common to both surfaces, and a delayed contact osteogenesis which seemed to follow different patterns at the two surfaces. In fact, SLA devices showed a more osteoconductive behavior retaining a less dense blood clot, which might be earlier and more easily replaced, and leading to a surface-conditioning layer which promotes osteogenic cell differentiation and appositional new bone deposition at the titanium surface. This model system is expected to provide a starting point for further investigations which clarify the early cellular and biomolecular events occurring at the metal surface

Multi-layer spiral CT with 2D, 3D and 4D volume rendered electronic reconstructions of wax models and natural bone made by Giuseppe Astorri kept at “Luigi Cattaneo” Museum in Bologna

The Museum’s collection of normal and pathological wax anatomical models provides a clear understanding of the developments in medical knowledge that took place during the 18th and 19th centuries. In this period the interest of the anatomists began to move from normal anatomy to pathological anatomy. The wax modelers made both types of wax anatomical models: normal and pathological. Our study investigates through the works of Giuseppe Astorri the differences between these two types of models, revealing hidden structures and materials used in a completely non-invasive way. The Computer Tomography (CT) analysis was carried out using an experimental CT system specifically designed for the analysis of Cultural Heritage materials, developed by the X-ray imaging research group at the Physics and Astronomy Department of the University of Bologna. The results of this project can also be shown through a dynamic 3D (i.e. 4D) virtual projection using a device capable of emulating a holographic representation

PEERS’ ANATOMY: teaching among students as an original approach to learning anatomy – a project made in Alma Mater

Anatomy is an ancient discipline which benefited greatly from technological improvements. Those very same technologies, along with a shift towards more clinically relevant topics, might be endangering anatomy’s central role as a cornerstone of medical education. A review of local realities showed anatomy to be quite uniformly taught by means of lectures alone. On the basis of our own experience, and comforted by references in literature (Day et al. [1]), we propose a revaluation of the teaching approach to anatomy, which includes an integration between different available resources and, above all, introduces peer-to-peer activity. Over the course of the last decade, based on a proposal from the Anatomy Department, more and more medical students took part to gross anatomy workshops abroad, thus consolidating what today is a large group of tutors. Working in parallel with the lectures, back home these students organize activities where notions are not a mere tool to pass the exam, but are aimed at giving younger students solid foundations on which to build their future competence. On the grounds of the experiences acquired in these years, we managed to divide the tutoring activities into six areas: surface and topographic anatomy, muscles and skeleton, heart and thorax, neuroanatomy, abdomen and pelvis, didactic coordination. Each group is based on the equal division of tasks and on respecting each tutor’s expertise, attitudes and skills. These workshops have proved to be highly effective both for students, as a chance to experience anatomy “hands-on”, and for tutors, as an opportunity of mastering the subject. Being appointed a tutor outlines a shift from a deductive learning method, typical of the pre-exam phase, to an inductive one, more useful in the future as medicine doctors. To sum up, the availability of adequate facilities for cadaveric dissection certainly enhances the teaching of anatomy; what our experience shows, however, is that only direct involvement of students as tutors brings out the full potential of these activities. We therefore propose abandoning a pure “learning-to-do” approach, in favour of a more effective “learning-by- doing” strategy

Osteogenesis and Morphology of the Peri-Implant Bone Facing Dental Implants

This study investigated the influence of different implant surfaces on peri-implant osteogenesis and implant face morphology of peri-implant tissues during the early (2 weeks) and complete healing period (3 months). Thirty endosseous titanium implants (conic screws) with differently treated surfaces (smooth titanium = SS, titanium plasma sprayed = TPS, sand-blasted zirconium oxide = Zr-SLA) were implanted in femur and tibiae diaphyses of two mongrel sheep. Histological sections of the implants and surrounding tissues obtained by sawing and grinding techniques were observed under light microscopy (LM). The peri-implant tissues of other samples were mechanically detached from the corresponding implants to be processed for SEM observation. Two weeks after implantation, we observed osteogenesis (new bone trabeculae) around all implant surfaces only where a gap was present at the host bone-metal interface. No evident bone deposition was detectable where threads of the screws were in direct contact with the compact host bone. Distance osteogenesis predominated in SS implants, while around rough surfaces (TPS and Zr-SLA), both distance and contact osteogenesis were present. At SEM analysis 2 weeks after implantation, the implant face of SS peri-implant tissue showed few, thin, newly formed, bone trabeculae immersed in large, loose, marrow tissue with blood vessels. Around the TPS screws, the implant face of the peri-implant tissue was rather irregular because of the rougher metal surface. Zr-SLA screws showed more numerous, newly formed bone trabeculae crossing marrow spaces and also needle-like crystals in bone nodules indicating an active mineralising process. After 3 months, all the screws appeared osseointegrated, being almost completely covered by a compact, mature, newly formed bone. However, some marrow spaces rich in blood vessels and undifferentiated cells were in contact with the metal surface. By SEM analysis, the implant face of the peri-implant tissue showed different results. Around the SS screws, the compact bone with areas of different mineralisation rate appeared very smooth, while around the rougher TPS screws, the bone still showed an irregular surface corresponding to the implant macro/microroughness. Around the Zr-SLA screws, a more regular implant-bone surface and sparse, calcified marrow spaces were detectable.Results from this research suggest that 2 weeks after implantation, trabecular bone represents the calcified healing tissue, which supports the early biological fixation of the implants. The peri-implant marrow spaces, rich in undifferentiated cells and blood vasculature, observed both 2 weeks and 3 months after surgery, favour the biological turnover of both early and mature peri-implant bone. The implant surface morphology strongly influences the rate and the modality of peri-implant osteogenesis, as do the morphology and arrangement of the implant face in peri-implant bone both during early healing (after 2 weeks) and when the implant is just osseointegrated; rough surfaces, and in particular Zr-SLA, seem to better favour bone deposition on the metal surface

Differential activation of nuclear inositide-dependent signalling pathways during erythropoiesis and myelopoiesis induced by lenalidomide and azacitidine in myelodysplastic syndromes (MDS)

Inositide-dependent signalling pathways regulated by phosphoinositide-specific phospholi- pase C (PI-PLC) beta1 have been demonstrated to play important roles in MDS pathogenesis and in cell differentiation (1). Moreover, the MDS therapy aims at inducing myeloid and/or erythroid differentiation of MDS stem cells. Indeed, azacitidine is a demethylating agent that can induce myeloid differentiation. On the other hand, lenalidomide may restore a normal erythropoiesis. The exact molecular mechanisms underlying the effect of azacitidine and lenalidomide in MDS cells are still unclear, although it is clear that these therapies regulate stem cell proliferation, differentiation and apoptosis (2). The combination of azacitidine and lenalidomide in MDS therapy is now under considera- tion, given the capability of both drugs to balance proliferation and differentiation processes (3). In this study we analyzed the molecular effect of this combination therapy on PI-PLC isoenzymes, not only studying PI-PLCbeta1, but also PI-PLCgamma1, that can be associated with erythropoiesis. We analyzed 44 patients diagnosed with high-risk MDS who were given azacitidine and lenalidomide. Given the limited number of cells, we quantified the expression of these molecules by Real-Time PCR analyses and immunocytochemical experiments. Moreover, we carried out cell cycle analyses and studied both PI-PLCbeta1 methylation status and the expression of Globin genes. In our case series, 28/44 patients were evaluable, with an overall response rate of 78.6% (22/28 cases). At a molecular level, a significant increase of PI-PLCbeta1 and/or PI-PLCgamma1 expression was associated with a favourable clinical response to the combination therapy. Responder cases also showed an increase of Beta-globin expression, hinting at a specific contri- bution of lenalidomide on erythroid activation, whilst the frequent demethylation of PI-PLCbeta1 promoter could be specifically linked to azacitidine. Taken together, our results show that the combination of azacitidine and lenalidomide can be important for activating PI-PLC isoenzymes, therefore regulating myeloid and erythroid dif- ferentiation in MDS cells

Hypo and retrotympanum: the importance of anatomical variants

The hypo- and retrotympanum host a variety of crucial anatomical structures1, characterized by high variability, which are poorly been described. The aim of our study is to describe and classify the anatomical variants of the hypo- and retrotympanum by the means of transcanal endoscopy2. We hypothesize that the retro- and hypotympanum are subject to more anatomical variability than actually thought. Moreover, the configuration as bridge variants and variably shaped sinus interconnects the different subregions. A total of 125 middle ears (83 cadaveric dissections) were explored by the means of 3mm straight and angled scopes. The variants were documented photographically and tabularized. The bony crests ponticulus, subiculum and finiculus1 were most frequently represented as ridges. The ponticulus showed the highest variability with 38% ridge, 35% bridge and 27% incomplete presentation. The subiculum was bridge - shaped only in 8% of the cases, while the finiculus in 17%. The sinus tympani had a normal shape in 66% of the cases. A subcochlear canaliculus was observed in 50%. The retro- and hypotympanum were classified respectively to the present bony crests and sinus in chambers type I to IV. In our opinion, the retro- and hypotympanum have to be considered as a tightly coherent region of the middle ear. For this purpose, we propose a straightforward classification, according to the presence of the different bony crests and sinus forming the different chambers of the retro- and hypotympanum. The introduced classification may also serve as intraoperative assessment, to be aware of the different anatomical subregions. The hidden areas of the retro- and hypotampanum are difficult to access and therefore represent a region of risk for residual cholesteatomatous disease after surgical treatment. The extension below a bridge bony crest or into a deep sinus demands thorough exploration; therefore, exact anatomical knowledge and an effective technique to visualize the whole middle ear are required