Browsing by Author "Fernandes, R."
Now showing 1 - 2 of 2
Results Per Page
Sort Options
- A novel semi-solid pill for stress-free voluntary oral drug administration in experimental rodentsPublication . Viana, Sofia; Martins, B.; Nunes, S.; Palavra, F.; Preguiça, I.; Alves, A.; Nóbrega, C.; Fernandes, R.; Silva, S.; Barbosa Moreira, Zélia; Lima, D.L.D.; Fontes-Ribeiro, Carlos; Reis, FlávioDuring compound screening and drug development, long-term oral drug administration to experimental rodents is often required. Oral gavage, a straightforward drug dosing technique, is not suitable for extended treatments considering the recurrent traumatic complications (gastroesophageal injury) and physiological distress (corticosterone levels alterations) that frequently bias experimental design outcomes. These reasons create a challenge for preclinical drug assays and stress-free/metabolic-inert alternatives of oral drug administration are warranted. Herein, it is presented an innovative semi-solid pill optimized to overcome aforementioned drawbacks. After a brief training period, C57BL/6 mice submitted to a chronic oral administration protocol (50 days) displayed a high index of voluntary acceptance of emptyand drug- (e.g. sitagliptin) incorporated vehicle in both healthy and CNS-diseased states. This protocol operates in a pair-housed animal housing fashion, allowing animal socialization throughout entire protocol. At the end of experiments, a normal neurobehavioral phenotype (anxiolytic, memory, locomotion parameters) was recorded. Moreover, this new methodology proved to be safe, preserving serum metabolic (glucose, triglycerides, total cholesterol), hepatic (albumin, total proteins) and renal (urea, creatinine, uric acid) parameters along with normal ileum contractility. Remarkably, coherent sitagliptin ( 10 mg/ml) plasma levels were detected, along with a robust decrease ( 80%) on the activity of its target (dipeptidyl peptidase- 4), unequivocally proving in vivo drug efficacy. Overall, this innovative approach may enclose a breakthrough advance for translational studies in scientific and pharmaceutical fields, providing a reproducible, efficient, metabolic inert and stress-free alternative for voluntary oral drug administration, with expected improvement on the data feasibility.
- Suitability of 3D printed pieces of nanocrystalline zirconia for dental applicationsPublication . Branco, A. C.; Silva, R.; Santos, T.; Jorge, H.; Rodrigues, A. R.; Fernandes, R.; Bandarra, S.; Barahona, I.; Matos, A. P. A.; Lorenz, K.; Polido, M.; Colaço, R.; Serro, A. P.; Figueiredo-Pina, C. G.Objectives: The main goal of this work is to evaluate the suitability of nanostructured zirconia pieces obtained by robocasting additive manufacturing (AM), for dental applications. Methods: The density, crystalline structure, morphology/porosity, surface roughness, hardness, toughness, wettability and biocompatibility of the produced samples were compared with those of samples obtained by conventional subtractive manufacturing (SM) of a similar commercial zirconia material. Chewing simulation studies were carried out against dental human cusps in artificial saliva. The wear of the material was quantified and the wear mechanisms investigated, as well as the influence of glaze coating. Results: AM samples, that revealed to be biocompatible, are slightly less dense and more porous than SM samples, showing lower hardness, toughness and wettability than SM samples. After chewing tests, no wear was found both on AM and SM samples. However, the dental wear was significantly lower when AM samples were used as counterbody. Concerning the glazed samples, both coated surfaces and dental cusps suffered wear, being the cusps’ wear higher than that found for unglazed samples. More, cusps tested against AM coated samples suffered less wear comparatively to those opposed to SM coated samples. Significance. Overall, the results presented in this paper show that AM processed nanostructured zirconia can be used in dental restorations, with important advantages from the point of view of processing and tribological performance. Moreover, the option for glaze finishing should be carefully considered both in SM and AM processed specimens.