Enhancement of the Biological and Mechanical Performances of Sintered Hydroxyapatite by Multiple Ions Doping

In the present work, hydroxyapatite (HA) nanoparticles doped with Mg2+, Sr2+, and Zn2+ ions are developed by wet neutralization method and then sintered at 1,250°C to obtain bulk consolidated materials. Physicochemical and microstructural analyses show that the presence of doping ions in the HA structure induced the formation of βTCP as secondary phase, during the sintering process, and we found that this effect is depending on the stability of the various doping ions in the hydroxyapatite lattice itself. We also found that the formation of βTCP as secondary phase, in turn, confines the grain growth of HA induced by the high-temperature sintering process, thus leading to a strong increase of the flexural strength of the bulk materials, according to Hall-Petch-like law. Furthermore, we found that the doping ions enter also in the structure of the βTCP phase; besides the grain growth confinement, also the solubility and ion release ability of the final materials were enhanced. In addition to ameliorate the mechanical performance, the described phenomena also activate multiple biofunctionalities: (i) ability to upregulate various genes involved in the osteogenesis, as obtained by human adipose stem cells culture and evaluated by array technology; (ii) enhanced resistance to the adhesion and proliferation of Gram+ and Gram– bacterial strains. Hence, our results open a perspective for the use of sintered multiple ion-doped HA to develop ceramic biodevices, such as plates, screws, or other osteosynthesis media, with enhanced strength, osteointegrability, and the ability to prevent post-surgical infections

Svelare i fattori di rischio che sottendono la chirurgia laringea negli anziani

I pazienti anziani non sono generalmente considerati buoni candidati per trattamenti terapeutici impegnativi, quali ad esempio la chirurgia molto invasiva e i complessi trattamenti radio-chemioterapici. Ma la loro esclusione dalle opzioni terapeutiche standard non sembrerebbe essere del tutto giustificabile. Nel presente lavoro abbiamo esaminato 212 pazienti di età ≥ 70 anni, affetti da carcinoma squamoso della laringe, trattati chirurgicamente con diverse opzioni terapeutiche: laserchirurgia transorale o chirurgia a cielo aperto (laringectomia parziale e/o totale). L’obiettivo principale era quello di confrontare i risultati, al fine di identificare fattori predittivi utili al chirurgo per scegliere la modalità di trattamento più opportuna. Nella presente coorte, i pazienti affetti da tumore più avanzato e quindi sottoposti a interventi chirurgici a cielo aperto (soprattutto laringectomia totale) risultano maggiormente inclini a sviluppare complicanze, andando incontro a esito fatale, rispetto a quelli con malattia precoce trattati con microchirurgia laser indipendentemente dall’ età al tempo dell’intervento chirurgico. In conclusione, i pazienti anziani affetti da cancro della laringe possono essere trattati come i pazienti più giovani, tenendo presente che interventi chirurgici più invasivi determinano un maggior rischio di complicanze. I vantaggi della chirurgia mininvasiva in termini di basso numero di complicanze tendono a renderla interessante come possibile trattamento di prima scelta nei pazienti molto anziani e fragili, anche in casi più avanzati. Infine le comorbidità, di per sé, non rappresentano una giustificazione per sottoporre gli anziani a trattamenti differenti da quelli standard

A Graded Multifunctional Hybrid Scaffold with Superparamagnetic Ability for Periodontal Regeneration

The regeneration of dental tissues is a still an unmet clinical need; in fact, no therapies have been completely successful in regenerating dental tissue complexes such as periodontium, which is also due to the lack of scaffolds that are able to guide and direct cell fate towards the reconstruction of different mineralized and non-mineralized dental tissues. In this respect, the present work develops a novel multifunctional hybrid scaffold recapitulating the different features of alveolar bone, periodontal ligament, and cementum by integrating the biomineralization process, and tape casting and electrospinning techniques. The scaffold is endowed with a superparamagnetic ability, thanks to the use of a biocompatible, bioactive superparamagnetic apatite phase, as a mineral component that is able to promote osteogenesis and to be activated by remote magnetic signals. The periodontal scaffold was obtained by engineering three different layers, recapitulating the relevant compositional and microstructural features of the target tissues, into a monolithic multifunctional graded device. Physico-chemical, morphological, and ultrastructural analyses, in association with preliminary in vitro investigations carried out with mesenchymal stem cells, confirm that the final scaffold exhibits a good mimicry of the periodontal tissue complex, with excellent cytocompatibility and cell viability, making it very promising for regenerative applications in dentistry. View Full-Tex

Chemical characterization of some substituted hydroxyapatites

Synthetic multi-substituted hydroxyapatite nano powders containing silicon and or carbonate prepared by a wet chemical method. The process parameters are set up to allow the simultaneous substitution of carbonate and silicon ions in the place of phosphorus. The chemical and structural characterizations of the prepared powders are determined with the aid of; XRF, ICP, XRD and FTIR. The results show that, the ion substitution in the crystal lattice of HA caused a change in the unit cell dimensions and affected the degree of crystallization of the produced powders. The apatite formation abilityy of the prepared discs from the synthesized powders is determined by immersing in SBF solution for different periods. The degree of ion release was determined in the obtained solutions. The examined surface of the immersed discs under SEM and analyzed by CDS showed a more dense HA layer than those of un-substituted ones. The HA with the substituted silicon and carbonate ions, showed the highest solubility with greater rate of ion release, compared with carbonate-free powder. All prepared powders took sodium ion from the SBF solution during immersion, which was not recorded before

Digital Food and foodways. How online food practices and narratives shape the Italian diaspora

The article discusses the role of online food practices and narratives in the formation of transnational identities and communities. Data has been collected in the framework of a doctoral research project undertaken by the author between 2009 and 2012 with a follow-up in 2014. The working hypothesis of this article is that the way Italians talk about food online and offline, the importance they give to ‘authentic’ food, and the way they share their love for Italian food with other members of the same diaspora reveal original insights into migrants’ personal and collective identities, their sense of belonging to the transnational community and processes of adjustment to a new place. Findings suggest that online culinary narratives and practices shape the Italian diaspora in unique ways, through the development of forms of virtual commensality and online mealtime socialization on Skype and by affecting intra and out-group relationships, thus working as elements of cultural identification and differentiation

Human osteoblast behaviour on as-synthesized SiO4 and B-CO3 co-substituted apatite

The functional behavior of synthetic apatite, commonly used as fillers or scaffolds, depends on physical and chemical parameters, which vary in response to chemical substitutions and to thermal treatments. The effect of silicon co-substituting with carbonate ions in the apatite lattice on the properties of the as-synthesized powder and finally on human osteoblast in vitro behavior was investigated. Dose-response curves of Si-free and Si-substituted carbonated apatites (namely CHA and SiCHA-1 and SiCHA-2 with 0.88 and 0.55 wt % of Si, respectively) showed that SiCHA-1 had toxic effect, whereas CHA and SiCHA-2, at worst, hindered osteoblast proliferation, but no toxicity occurred. Subsequent experiments compared the effects of CHA and SiCHA-2 used at the doses of 0.3 and 1 mg/mL. After 7 days of treatment, both the powders stimulated cell proliferation and protein content and inhibited alkaline phosphatase activity. However, SiCHA-2 slightly stimulated osteoblast differentiation, as shown by higher calcium deposition, compared with CHA. The cell behaviors were linked to the peculiar powder characteristics. The as-synthesized powder represents the most critical system in terms of reactivity toward cells and can inform on the limits for positively exploiting the characteristics of SiCHA powders in making bone fillers or scaffolds, using no thermal treatment