INJECTABLE HYBRID SYSTEM FOR STRONTIUM LOCAL DELIVERY TO PROMOTE BONE REGENERATION

In bone tissue regeneration strategies, injectable bone substitutes are very attractive since they can be applied with minimally invasive surgical procedures and can perfectly fill irregular defects created in cases of trauma, infection or tumor resection. These materials must combine adequate mechanical properties with the ability to induce new bone formation. Incorporating strontium (Sr) in bone substitute biomaterials may be a strategy to achieve high Sr concentrations, not in a systemic but in a local environment, taking advantage of the osteoanabolic and anti-osteoclastic activity of Sr, for the enhancement of new bone formation. In this context, the aim of the present work was to evaluate the response of a Sr-hybrid injectable system for bone regeneration, designed by our group, consisting of hydroxyapatite microspheres doped with Sr and an alginate vehicle crosslinked in situ with Sr, in an in vivo scenario. Two different animal models were used, rat (Wistar) and sheep (Merino Branco) critical sized bone defect. Non Sr-doped similar materials (Ca-hybrid) or empty defects were used as control. Sr-hybrid system led to an increased bone formation in both center and periphery of a rat critical sized defect compared to a non Sr–doped similar system, where new bone formation was restricted to the periphery. Moreover newly formed bone was identified as early as one week after its implantation in a sheep model. After eight weeks, the bone surrounded the microspheres, both in the periphery and in the center of the defect. Most importantly, the hybrid system provided a scaffold for cell migration and tissue ingrowth and offered structural support, as observed in both models. The effective improvement of local bone formation suggests that this might be a promising approach for bone regeneration, especially in osteoporotic conditions

IN VIVO STUDY OF THE EFFECT OF A STRONTIUM-­‐RICH INJECTABLE SYSTEM ON BONE REGENERATION, USING A SHEEP MODEL

Bone has the capacity to regenerate as part of the repair process,being newly formed boné indistinguishable from the adjacente uninjured bone. However,there are cases in which boné regeneration is required in large quantity, beyond the normal potential for self-­‐healing, such as for lesions caused by trauma, infection, tumour resection or cases in which the regenerative process is compromised such as avascular necrosis and osteoporosis. Biomaterials such as alginate are very promising due to its ability to form hydrogels in situ under mild conditions in the presence of divalente cations. The combination with ceramic microspheres results in a mechanically improved injectable system, adequate for minimally invasive procedures. Moreover, the combination with chemical elements such as strontium, described as promoter of boné formation, inhibiting boné resorption provides ion Exchange between the implanted biomaterial and surrounding tissue, enhancing boné regeneration. Our goal is to study in na invivo sheep model, the effect of na injectable system composed of strontium doped hydroxyapatite microspheres, delivered in na alginate vehicle, crosslinked with strontium

Boundary critical behavior at m-axial Lifshitz points for a boundary plane parallel to the modulation axes

The critical behavior of semi-infinite $d$-dimensional systems with $n$-component order parameter $\bm{\phi}$ and short-range interactions is investigated at an $m$-axial bulk Lifshitz point whose wave-vector instability is isotropic in an $m$-dimensional subspace of $\mathbb{R}^d$. The associated $m$ modulation axes are presumed to be parallel to the surface, where $0\le m\le d-1$. An appropriate semi-infinite $|\bm{\phi}|^4$ model representing the corresponding universality classes of surface critical behavior is introduced. It is shown that the usual O(n) symmetric boundary term $\propto \bm{\phi}^2$ of the Hamiltonian must be supplemented by one of the form $\mathring{\lambda} \sum_{\alpha=1}^m(\partial\bm{\phi}/\partial x_\alpha)^2$ involving a dimensionless (renormalized) coupling constant $\lambda$. The implied boundary conditions are given, and the general form of the field-theoretic renormalization of the model below the upper critical dimension $d^*(m)=4+{m}/{2}$ is clarified. Fixed points describing the ordinary, special, and extraordinary transitions are identified and shown to be located at a nontrivial value $\lambda^*$ if $\epsilon\equiv d^*(m)-d>0$. The surface critical exponents of the ordinary transition are determined to second order in $\epsilon$. Extrapolations of these $\epsilon$ expansions yield values of these exponents for $d=3$ in good agreement with recent Monte Carlo results for the case of a uniaxial ($m=1$) Lifshitz point. The scaling dimension of the surface energy density is shown to be given exactly by $d+m (\theta-1)$, where $\theta=\nu_{l4}/\nu_{l2}$ is the anisotropy exponent.Comment: revtex4, 31 pages with eps-files for figures, uses texdraw to generate some graphs; to appear in PRB; v2: some references and additional remarks added, labeling in figure 1 and some typos correcte

Symmetric Hyperbolic System in the Self-dual Teleparallel Gravity

In order to discuss the well-posed initial value formulation of the teleparallel gravity and apply it to numerical relativity a symmetric hyperbolic system in the self-dual teleparallel gravity which is equivalent to the Ashtekar formulation is posed. This system is different from the ones in other works by that the reality condition of the spatial metric is included in the symmetric hyperbolicity and then is no longer an independent condition. In addition the constraint equations of this system are rather simpler than the ones in other works.Comment: 8 pages, no figure

Clinical, ultrasonographic and pathological aspects of iatrogenic thrombophlebitis in a mare - case report

ABSTRACT A 7-year-old quarter horse mare showed swelling of the tongue, head and neck region, dyspnea, and red urine after eight days of administration of intravenous medications by the animal's handler. The horse was referred to the University Veterinary Hospital of the Federal University of Pará and, at the clinical examination, showed apathy, edema in the head, neck, and tongue region, which was slightly cyanotic and with loss of epithelium in the dorsal region. The maxillary, linguofacial and external jugular veins were bilaterally engorged, firm to palpation and with cord-shaped appearance, with extension of the head to the entrance to the thoracic cavity. Ultrasound examination showed a thrombi with a hyperechoic and heterogeneous appearance that completely obstructed the vessel. The horse died five days after entering the Hospital and at necropsy it was observed: maxillary, linguofacial and external jugular veins bilaterally filled with firm, dark red to blackish thrombi; ulcerated areas in the final third of the esophagus and the stomach; lighter areas on the surface of the kidneys and dark areas at the corticomedullary junction. Based on clinical, ultrasonographic and necropsy findings, iatrogenic thrombophlebitis was diagnosed, associated with repeated injections of drugs administered intravenously

Calcium phosphate-alginate microspheres as enzyme delivery matrices

The present study concerns the preparation and initial characterisation of novel calcium titanium phosphate-alginate (CTPalginate) and hydroxyapatite-alginate (HAp-alginate) microspheres, which are intended to be used as enzyme delivery matrices and bone regeneration templates. Microspheres were prepared using different concentrations of polymer solution (1% and 3% w/v) and different ceramic-to-polymer solution ratios (0.1, 0.2 and 0.4 w/w). Ceramic powders were characterised using X-ray diffraction, laser granulometry, Brunauer, Emmel and Teller (BET) method for the determination of surface area, zeta potential and Fourier transform infrared spectroscopy (FT-IR). Alginate was characterised using high performance size exclusion chromatography. The methodology followed in this investigation enabled the preparation of homogeneous microspheres with a uniform size. Studies on the immobilisation and release of the therapeutic enzyme glucocerebrosidase, employed in the treatment of Gaucher disease, were also performed. The enzyme was incorporated into the ceramic-alginate matrix before gel formation in two different ways: preadsorbed onto the ceramic particles or dispersed in the polymeric matrix. The two strategies resulted in distinct release profiles. Slow release was obtained after adsorption of the enzyme to the ceramic powders, prior to preparation of the microspheres. An initial fast release was achieved when the enzyme and the ceramic particles were dispersed in the alginate solution before producing the microspheres. The latter profile is very similar to that of alginate microspheres. The different patterns of enzyme release increase the range of possible applications of the system investigated in this work.info:eu-repo/semantics/publishedVersio

Aspectos sociales, sobrecarga y calidad de vida de las madres de niños con microcefalia

Introducción: Cuidar completamente de niños con microcefalia es un gran desafío para sus cuidadores. La situación de vulnerabilidad social junto con la complejidad de la atención puede llevar a sobrecarga con pérdida de la calidad de vida. Objetivo: Analizar la relación entre aspectos socioeconómicos, dominio social de la calidad de vida y la sobrecarga de madres cuidadoras de niños con microcefalia. Metodología: Estudio transversal con 105 participantes, mediante aplicación de cuestionarios sociodemográficos, WHOQOL-BREF, sobrecarga del cuidador. Se utilizaron pruebas ANOVA, t de Student, correlación Pearson (r). Resultados: Población de madres mestizas (65.7 %), desempleadas (88.6 %), dependientes de la prestación social (76.2 %), bajo nivel educativo (50.5 %) e insuficiencia financiera (90.5 %). El promedio del dominio social se consideró bajo (51.11). Hubo asociación entre beneficio social y puntaje de calidad de vida total (p= 0.046). Las madres sufren sobrecarga severa (39 %) e intensa (30.4 %). Se encontró asociación entre niveles de sobrecarga y variables etnia (p= 0.027), ocupación (p= 0.043) y medios de transporte (p <0.0001). La sobrecarga tiene impacto negativo en la calidad de vida (r= -.463, p <0.0001), percepción de la calidad de vida (r= -.476, p= <0.0001), calidad de vida total (r= -.576, p= <0.0010). Conclusiones: Las madres cuidadoras manifiestan sobrecarga con pérdida de calidad de vida. Los aspectos sociales influyen directamente y pueden potenciar la sobrecarga del cuidado. El personal de enfermería tiene un papel fundamental para crear e implementar líneas de atención con énfasis en promover la salud y alivio de la sobrecarga en el cuidador

Novas perspectivas na reconstituição do modo de vida dos sambaquieiros: uma abordagem multidisciplinar

A reunião de dados originais e de revisões da literatura, numa abordagem multidisciplinar praticamente inédita na arqueologia brasileira, forneceu subsídios para um melhor conhecimento da sociedade sambaquieira. Análises antracológicas permitiram a reconstrução paleoecológica do ambiente costeiro, além de prover informações sobre a economia do combustível nesta sociedade e sua dieta. Análises paleopatológicas revelaram aspectos importantes do modo de vida dos sambaquieiros e de sua relação com o meio ambiente. A combinação dos resultados destas duas disciplinas, associadas a análises líticas, apontou para um espectro econômico e de subsistência bem mais amplo do que se supunha anteriormente, confirmou a importância das plantas para esta sociedade e forneceu bases mais sólidas para o debate a respeito de manejo e cultivo de vegetais