Ana Portela

An in vitro and in vivo investigation of the biological behavior of a ferrimagnetic cement for highly focalized thermotherapy

The cancer treatment by local hyperthermia, using a high frequency electromagnetic field is an extensively studied subject. For this propose it was developed a ferrimagnetic cement (FC) to be injected directly into the tumor. In this study it was determined the FC injectability, its capability to generate heat when placed within a magnetic field and its interaction with a modified simulated body fluid using SEM/EDS and XRD. The FC biological response was assessed by the intramuscular implantation in rats and histological analysis of the surrounding tissues. The results suggest that FC can be injected directly into the tumor, its temperature can be increased when exposed to a magnetic field and the surface of the immersed samples quickly becomes coated with precipitate denoting its ionic change with the surrounding medium. The histological analysis revealed a transient local inflammatory reaction, similar to the control material, only slightly more abundant during the first weeks, with a gradual decrease over the implantation time. Based on these results, we concluded that FC might be useful for highly focalized thermotherapy, with a good potential for clinical use.

Highly focalised thermotherapy using a ferrimagnetic cement in the treatment of a melanoma mouse model by low temperature hyperthermia

Purpose: Evaluation of the effectiveness of highly focalised thermotherapy (HFT) in a melanoma mouse model, using a ferrimagnetic cement (FC) and repeated low hyperthermia treatments. Materials and methods: A melanoma mouse model was induced with B16F10 cells in C57BL6 mice. The FC, injected into the tumour, was used as the magnetic vehicle for HFT. FC location within the tumour was assessed by radiography and its capability to generate heat, when exposed to an external high frequency magnetic field (HFMF), monitored by thermal camera. The HFT treatment consisted of three HFMF exposures, with 48-h intervals, each one lasting 30 min, with a 5–6°C tumour temperature increase. At the end of the experiment, FC samples were characterised by scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS). The presence of iron contents was analysed in the tumour, lungs, liver and spleen. Histological evaluation and immunohistochemical staining for caspase-3 were performed. Tumour growth was monitored during the experiment. Results: Surface analysis showed FC stabilisation within the tumour, and iron was absent. The thermal camera confirmed the localised temperature increase in the tumour. HFT treatments inhibited the tumour growth by ∼70% compared to controls. This was due to cell destruction by necrosis and apoptosis. Conclusions: The HFT, using the FC, proved to be a minimally invasive technique that statistically inhibited tumour growth. Results suggested that this methodology seems to be a promising technique for the treatment of solid tumours, allowing repeated low hyperthermia treatments, which can be easier and less traumatic than other hyperthermia techniques.

Bryophyte communities of Mediterranean Europe: a first approach to model their potential distribution in highly seasonal rivers

Abstract Mediterranean watercourses are among the most threatened ecosystems worldwide, being increasingly important to understand environmental drivers of biotic assemblages. Our aim was to provide a comprehensive picture of bryophyte communities in Mediterranean rivers and to determine the environmental factors that influence their distribution. We used floristic data collected for inter-calibration purposes under the European Water Framework Directive and River Habitat Survey, from 474 river reaches in six countries of the European Mediterranean basin. We analysed data through classification, ordination and environmental niche modelling techniques, and classified taxa according to biogeographic and aquatic habitat frameworks developed specifically for bryophytes. These analyses revealed four types of communities influenced by spatio-temporal precipitation patterns, altitude and water chemistry factors, most notably calcium and manganese. Community types are compositionally differentiated, although they share some core taxa and show an overall tendency to have several temperate and exclusively aquatic taxa despite the intermittent nature of water flow in highly seasonal Mediterranean rivers. The modelling approach can be improved at a more local scale when more bryological data and higher-resolution environmental information become available. Given future scenarios of climate change and human alteration of hydrological regimes, broader scales studies are needed to monitor shifts in bryophyte communities.

The interplay between total mercury, methylmercury and dissolved organic matter in fluvial systems: A latitudinal study across Europe

Large-scale studies are needed to identify the drivers of total mercury (THg) and monomethyl-mercury (MeHg) concentrations in aquatic ecosystems. Studies attempting to link dissolved organic matter (DOM) to levels of THg or MeHg are few and geographically constrained. Additionally, stream and river systems have been understudied as compared to lakes. Hence, the aim of this study was to examine the influence of DOM concentration and composition, morphological descriptors, land uses and water chemistry on THg and MeHg concentrations and the percentage of THg as MeHg (%MeHg) in 29 streams across Europe spanning from 41°N to 64 °N. THg concentrations (0.06-2.78 ng L-1) were highest in streams characterized by DOM with a high terrestrial soil signature and low nutrient content. MeHg concentrations (7.8-159 pg L-1) varied non-systematically across systems. Relationships between DOM bulk characteristics and THg and MeHg suggest that while soil derived DOM inputs control THg concentrations, autochthonous DOM (aquatically produced) and the availability of electron acceptors for Hg methylating microorganisms (e.g. sulfate) drive %MeHg and potentially MeHg concentration. Overall, these results highlight the large spatial variability in THg and MeHg concentrations at the European scale, and underscore the importance of DOM composition on mercury cycling in fluvial systems.

Dental stem cells Characterization and Bone Regenerative Potential in oral Medicine

C l i n M e d International Library Citation: Rodrigues R, Viana B, Vieira I, Tavares J, Lobo R, et al. (2015) Dental Stem Cells Characterization and Bone Regenerative Potential in Oral Medicine. Int J Stem Cell Res Ther 2:009 Received: April 30, 2015: Accepted: May 31, 2015: Published: June 02, 2015 Copyright:

The effect of a biphasic calcium phosphate on bone healing: a pilot study in rats.

PURPOSE The primary objective of this pilot study was to evaluate the effectiveness of biphasic calcium phosphate (BCP) covered with a polyethylene glycol (PEG) membrane in the regeneration of 5-mm-diameter defects created in the calvaria of Wistar rats and compare this with the regeneration of defects covered only with the PEG membrane. MATERIALS AND METHODS Two 5-mm-diameter parietal defects were created in seven Wistar rats. The control defect in the left parietal bone was covered with an experimental PEG membrane (Straumann MembraGel); the test defect in the right parietal bone was filled with BCP (Straumann BoneCeramic) and covered with the same membrane. After a healing period of 2 months, the animals were sacrificed, and the samples were processed for histologic and histomorphometric analysis. RESULTS The test defects regenerated with BCP and covered with the PEG membrane had a percentage of new bone formation area of 61.7% ± 14.6%, and the control defects obtained mean new bone area of 57.3% ± 21.8%. The difference between groups was not statistically significant. The BCP did not reveal osteoconductive properties, and few particles were fully incorporated into the newly formed bone. The BCP maintained the space, and there was extremely low particle resorption during the healing period. The PEG membrane remained intact. CONCLUSION There were no statistically significant differences between the test and control groups. BCP did not exhibit osteoconductive properties.

Thermographic Evaluation of the Saxophonists’ Embouchure

The orofacial complex is the primarily link between the instrument and the instrumentalist when performing the musician’s embouchure. The contact point is established between the saxophonist lower lip, the upper maxillary dentition and the mouthpiece. The functional demands of the saxophone player and consequent application of forces with an excessive pressure can significantly influence the orofacial structures. A thermographic evaluation was performed to an anatomical zone vital for the embouchure, such as the lip of the saxophonist. Substantial temperature changes occurred before and after playing saxophone. The specificity of the embouchure regarding the position of the lower lip inside the oral cavity, the anatomy and position of the central lower incisors can be some of the factors involved in the origin of the existing temperature differences on the thermographic evaluation.