Self-Photopolymerizable Hydrogel-Ceramic Composites with Scavenger Properties.

The photocatalytic behaviours of semiconductive ceramic nanoparticles such as TiO2, ZnO, Fe2O3, and Fe3O4, have been extensively studied in photocatalysis and photopolymerization, due to their ability to produce radical species under ultraviolet-visible light, and even in dark conditions. In addition, in the form of microparticles, TiO2 and its Magnéli phases are capable of neutralizing radical species, and a heterogeneous catalytic process has been suggested to explain this property, as it is well known as scavenging activity. Thus, in this study, we demonstrate that these ceramic powders, in the form of microparticles, could be used as photoinitiators in UV polymerization in order to synthesize a hydrogel matrix. Them, embedded ceramic powders could be able to neutralize radical species of physiological media once implanted. The hydrogel matrix would regulate the exchange of free radicals in any media, while the ceramic particles would neutralize the reactive species. Therefore, in this work, the scavenger activities of TiO2, ZnO, Fe2O3, and Fe3O4 microparticles, along with their photoinitiation yield, were evaluated. After photopolymerization, the gel fraction and swelling behaviour were evaluated for each hydrogel produced with different ceramic initiators. Gel fractions were higher than 60%, exhibiting variation in their scavenging activity. Therefore, we demonstrate that ceramic photoinitiators of TiO2, ZnO, Fe2O3, and Fe3O4 can be used to fabricate implantable devices with scavenger properties in order to neutralize radical species involved in inflammatory processes and degenerative diseases.

Novel Osteoinductive and Osteogenic Scaffolds of Monetite, Amorphous Calcium Phosphate, Hydroxyapatite, and Silica Gel: Influence of the Hydroxyapatite/Monetite Ratio on Their In Vivo Behavior and on Their Physical and Chemical Properties.

In this work, a new family of multiphasic materials composed of the same amount of silica gel and variable amount of three calcium phosphates with very different solubilities, monetite > amorphous calcium phosphate > hydroxyapatite (HAp), was studied. Silicon was added to calcium phosphate to increase bioactivity and osteinductivity. The influence of the HAp/monetite ratio on the material resorption and bone regeneration was investigated in critical bone defects in sheep and was related to their chemical and physical properties. It was concluded that a minimum rate of HAp/monetite is necessary to achieve an appropriate compromise between material resorption and bone regeneration. Above this minimum rate, bone regeneration and material resorbtion did not change significantly. Physical properties such as particle size, specific surface area, porosity, and granulate cohesion played a more critical role on material resorption than the solubility of their components. A huge difference between in vitro solubility and in vivo resorption was observed. It was related to the fastest cellular-mediated resorption of monetite compared to the other components. Computerized axial tomography, histology, histomorphometric, and multiple fluorochrome labeling studies showed a very advanced bone regeneration of the defects when materials with the highest HAp/monetite rate were implanted. It was also demonstrated that all materials induce bone formation and vascularization.

Management of purpura fulminans skin lesions in a premature neonate with sepsis: a case study.

Purpura fulminans is a severe and rapidly progressive septic process characterised by the development of haemorrhagic and ecchymotic lesions and skin necrosis. It can appear on any part of the body but predominantly affects the limbs. Purpura fulminans is a rare but possible complication in paediatric patients, especially neonates. It can increase their risk of morbidity and mortality if not treated early and cause a severe long-term condition in survivors of the infectious episode, including amputation. For professionals involved in wound healing, purpura fulminans poses a major challenge. This report describes the case of a premature neonate with extensive purpura fulminans of the legs and arms. Topical treatment of the limbs and purpuric areas with hyperoxygenated fatty acids (HOFAs) every two hours produced an improvement in the lesions. Complete healing was achieved using moist wound healing products. Early topical application of HOFAs appears to be a safe treatment that improves tissue microcirculation in paediatric patients with Purpura fulminans, minimising sepsis-related skin damage.

External and internal ontogenetic changes in the first rib.

OBJECTIVES: First ribs bear information about thorax morphology and are usually well preserved, compared to other ribs, in bone/fossil samples. Several studies have addressed ontogeny of the first rib by studying changes in bone microanatomy and rib morphology separately, but no studies have combined both approaches to study how internal and external changes covary during ontogeny. The aim of this project is to fill this gap in our knowledge. MATERIALS AND METHODS: We applied 3D geometric morphometrics of sliding semilandmarks to 14 first ribs of Homo sapiens to quantify rib curvature and mid-shaft cross-section outline. Ontogenetic variation was addressed throughout a principal component analysis (PCA). Additionally, we made histological sections at the mid-shaft of the same ribs and studied tissue matrix composition and compartmentalization. Finally, we performed partial least squares (PLS) and regression analyses to study covariation between rib morphology and compartmentalization variables. RESULTS: PCA shows that first ribs increase their curvature over the course of ontogeny and the rib midshaft becomes less rounded during ontogeny. In addition, the sternal end becomes more medially oriented during ontogeny and the relative head-tubercle distance becomes longer. Compartmentalization shows a decrease in the area occupied by mineralized tissues and an increase in the area occupied by non-mineralized tissues over the course of ontogeny, which covaries with mid-shaft cross-section shape. CONCLUSIONS: Our results show detailed variation in rib morphology along with histological changes in bone tissue compartmentalization and, for the first time, the correlation between the two. This could be related to muscle attachments on the 1st rib and also to changes in breathing mode, from diaphragmatic in perinatals to pulmonary in adults, which could also have implications for understanding thorax evolution.

Targeting neural stem cells with titanium dioxide nanoparticles coupled to specific monoclonal antibodies.

Aiming to characterize the use of biomaterials in cancer therapy, we took advantage of the n-type semiconductor properties, which upon irradiation excite their electrons into the conduction band to induce photoelectrochemical reactions generating oxygen reactive species (ROS). Indeed, photoactivated TiO(2) nanoparticles have been shown to kill in vitro either bacteria or tumor cells in culture following UV irradiation, as a consequence of the ROS levels generated; the killing was highly effective although devoid of specificity. In this report, we have directed the TiO(2) nanoparticles to particular targets by coupling them to the monoclonal antibody (mAb) Nilo1, recognizing a surface antigen in neural stem cells within a cell culture, to explore the possibility of making this process specific. TiO(2) nanoparticles generated with particular rutile/anatase ratios were coupled to Nilo1 antibody and the complexes formed were highly stable. The coupled antibody retained the ability to identify neural stem cells and upon UV irradiation, the TiO(2) nanoparticles were activated, inducing the selective photokilling of the antibody-targeted cells. Thus, these data indicate that antibody-TiO(2) complexes could be used to specifically remove target cell subpopulations, as demonstrated with neural stem cells. The possible applications in cancer therapy are discussed.