Evaluation of the Effect of the Microscopic Glass Surface Protonation on the Hard Tissue Thin Section Preparation

In this study, a new procedure for mounting tissue blocks was described while cutting and grinding the section remains tightly bound to the inert glass surface both chemically and micro mechanically allowing good quality specimens for staining and microscopic analysis. The micromechanical interlocking was achieved by using of frosted glass, the chemical binding was made with 10-methacryloyloxydecyl dihydrogen phosphate monomer (10-MDP) containing bond material. The glass surface activation was achieved by nitric acid etching and the surface was characterized by zeta potential, X-ray photoelectron spectroscopy (XPS), and contact angle measurements. Cylindrical samples were prepared from epoxy embedding materials, cortical bovine bone, and dental titanium to investigate the shear bond strengths (SBS) to microscopic glass slide compared to a routinely used thermoplastic adhesive. Based on the experiments it was found that the micromechanical retention combined with MDP containing bond material improved the SBS data compared to the thermoplastic adhesive. The acid etched glass became positively charged that significantly increased the SBS data of bone and titanium compared with the uncharged version. Therefore, the thickness of the undecalcified bone section with metal can safely reduce to improve histological microscopic analysis.

Viability of Bos taurus scapulae as a flat bone proxy for ballistic testing

BackgroundHandguns and rifles are often involved in violent deaths such as homicide and suicide. Consequently, forensic investigations are important to clarify the nature of ballistic trauma.MethodsThis study investigated the differences in entrance and exit wound morphology with Bos taurus (bovine) scapulae that have two cortical layers surrounding a central cancellous bone section which are comparable with human flat bones, with a series of experiments using six different calibres (0.22 Long Rifle, 9×19 mm North Atlantic Treaty Organization, 0.40 Smith & Wesson, 0.45 Automatic Colt Pistol, 5.56×45 mm and 7.62×51 mm). B. taurus (bovine) scapulae were used for closed range 30 cm simulated executions.ResultsThe ballistic experiments presented similarities in entrance wound morphology and exit wound bevelling with that of recognised forensic cases. As muzzle velocity increased, bevelling increased. Circumferential delamination is clearly visible with full metal jacket rounds, yielding similar bone damage morphology as human crania.ConclusionBovine scapulae seem appropriate for ballistic simulations of flat bone injuries on the macroscopic level, if the correct portion of the scapulae is deployed. More research is needed to further substantiate these interpretations.

Method for the prevention of inflammatory processes in the bone part of the external auditory canal accompanied by the growth of connective tissue

Otosurgery plays an important role in the rehabilitation of patients with hearing loss. Any operation can be accompanied by a long inflammatory process with excessive development of connective tissue, forming atresia or stenosis of the external auditory canal. Formed scars in the external auditory canal reduce the effectiveness of treatment and can lead to reoperation. In the treatment of scars, the use of injections of a suspension of prolonged steroids directly into the developing connective tissue is effective. We have developed a method of injecting drugs into the scar tissue of the bone section of the external auditory canal, which allows the use of such therapy in patients after otosurgery. 12 people were treated with the proposed technique. All patients had an inflammatory process in the external auditory canal with undesirable growth of connective tissue. Previous local therapy did not bring a satisfactory result. Patients received injections of a suspension of steroids into developing scar tissue. The treatment period was 1-8 weeks, for which 1 to 4 sessions of injections were performed. As a result of treatment according to the developed method, in all cases a cessation of the pathological inflammatory process was observed. Timely therapy made it possible to completely eliminate the excess granulation tissue (100%), to stop the growth of the scar, or even to cause a significant decrease (33%). The developed method allows to use of a small dose of a substance (0,1–0,5 ml) for injection to achieve the desired therapeutic effect.

Patient-Specific Bone Multiscale Modelling, Fracture Simulation and Risk Analysis—A Survey

This paper provides a starting point for researchers and practitioners from biology, medicine, physics and engineering who can benefit from an up-to-date literature survey on patient-specific bone fracture modelling, simulation and risk analysis. This survey hints at a framework for devising realistic patient-specific bone fracture simulations. This paper has 18 sections: Section 1 presents the main interested parties; Section 2 explains the organzation of the text; Section 3 motivates further work on patient-specific bone fracture simulation; Section 4 motivates this survey; Section 5 concerns the collection of bibliographical references; Section 6 motivates the physico-mathematical approach to bone fracture; Section 7 presents the modelling of bone as a continuum; Section 8 categorizes the surveyed literature into a continuum mechanics framework; Section 9 concerns the computational modelling of bone geometry; Section 10 concerns the estimation of bone mechanical properties; Section 11 concerns the selection of boundary conditions representative of bone trauma; Section 12 concerns bone fracture simulation; Section 13 presents the multiscale structure of bone; Section 14 concerns the multiscale mathematical modelling of bone; Section 15 concerns the experimental validation of bone fracture simulations; Section 16 concerns bone fracture risk assessment. Lastly, glossaries for symbols, acronyms, and physico-mathematical terms are provided.

Protein and bone health across the lifespan

Bone health is determined by the rate of accrual in early life, followed by the rate of age-associated bone loss. Dietary protein intake might have a role in bone health across both of these phases via pleiotropic mechanistic pathways. Herein we summarise the pathways through which protein may exert either a positive or negative influence on bone. In the introduction, we describe the acid-ash hypothesis, which states that a high-protein intake may lead to an acidic residue that must be neutralised through the leaching of calcium and other minerals from the bone, subsequently leading to demineralisation and bone weakening. Conversely, and as described in the ‘Against: mechanisms through which protein may negatively impact bone’ section, protein intake may act to strengthen the bone by stimulating the activity of various anabolic hormones and growth factors, or by optimising muscle mass and functionality, which itself has an osteogenic influence. The net effect of these contrasting pathways is described in the ‘For: mechanisms through which protein may positively impact bone’ section, where a number of meta-analyses have demonstrated that higher protein intakes have a small positive impact on bone mass and fracture risk. Sometimes higher than recommended protein intakes are advised, e.g. during the earlier and later phases of the lifespan or during reduced energy availability. We conclude that protein is an essential nutrient for bone health, although further research is required to clarify the mechanistic pathways through which it exerts its influence, along with the clarification of the quantities, food sources and timing to allow for the optimisation of this protective influence and ultimately a reduction in fracture risk.

New dental implant selection criterion based on implant design

ABSTRACT Objective: A comparative study between threaded and plain dental implant designs was performed to find out a new criterion for dental implant selection. Materials and Methods: Several dental implant designs with a systematic increase in diameter and length were positioned in a cylindrical-shaped bone section and analyzed using finite element method. Four loading types were tested on different dental implant designs; tension of 50 N, compression of 100 N, bending of 20 N, and torque of 2 Nm, to derive design curves. Results: Better stress distribution on both spongy and cortical bone was noted with an increase in dental implant diameter and length. With the increase in dental implant side area, a stress reduction in the surrounding bones was observed, where threaded dental implants showed better behavior over the plain ones. Conclusions: Increasing value of ratio between dental implant side area and its cross-sectional area reduces stresses transferred to cortical and spongy bones. The use of implants with higher ratio of side area to cross-section area, especially with weak jaw bone, is recommended.

Investigation of elemental distribution in cat femoral head by nuclear microprobe and SEM for Paget disease of bone studies

Paget Disease of Bone is a disorder characterized by abnormal bone remodeling, associated with morphological and functional abnormalities of osteoclasts although its etiology remains unproven. Ion beam analysis (IBA) techniques may be useful to characterize the abnormal distribution and concentration of the major and trace elements that can be associated topagetic bone condition. In order to access the viability of this approach, healthy femoral head of cat has been investigated by Particle Induced X-Ray Emission (PIXE),Rutherford Backscattering Spectrometry (RBS) and Scanning Electron Microscopy (SEM).The bone section was irradiated, under vacuum conditions, with a 2.0 MeV alpha particle beam produced by the 2.5 MV Van de Graaff Accelerator of CTN/IST (Lisbon, Portugal). An Oxford Microbeams-type nuclear microprobe was used (OM150 triplet system), which allowed the proton beam to be focused on the bone section with a spatial resolution of 3x4 µm2 and a mean beam current of ~90pA. The X-rays generated by the bone were recorded using an 80 mm2 Link X-ray detector (with a 145 eV energy resolution), that is positioned at 135º to the beam direction. The backscattered particles were collected by a 200 mm2 silicon surface barrier radiation detector with a 15 keV energy resolution that is positioned at 40º to the beam direction in a cornell geometry. SEM observations have been carried out with backscattered electrons (BSE) using a JEOL JSM 7001F microscope equipped with an INCA Oxford Instruments EDS spectrometer for point analyses and X-ray mapping. Standard petrographic procedures have been employed to prepare the samples for SEM observation: the specimens were partly encapsulated in epoxy resin, ground with 800 and 1000-grit SiC paper, polished with 6 μm and 1 μm diamond suspensions and coated with carbon.A selected area of the sample has been scanned with the proton beam, allowing to generateelemental distribution maps for Ca and P (Figure 1). From X-line scans it was possible to extractline profiles of these elements. RBS and PIXE were used to determine the matrix and trace element composition in order to normalize the elemental concentrations. The results are shown in Table 1.Structural information on the Haversian Systems, includingbone lacunaeandosteocytes localization have been obtained by SEM (Figure 2).The combination of these techniques proved to be a viable approach for the Pagetic bone characterization and will be used to analyze the structure of trabecular and cortical bones as well as the distribution and morphology of the pagetic bone cells, which can contribute to clarify the differences between pagetic and healthy bone.V. Corregidor acknowledges the support from FCT-Ciência program. The work was also supported by FCT PEST-OE/CTM-UI0084/2011 grant.