Cellular prion protein regulates the motor behaviour performance and anxiety-induced responses in genetically modified mice

The cellular prion protein (PrP(C)) is a sialoglycoprotein involved in neuroplasticity processes and synaptic transmission. This study investigated behavioural responses (balance in the rota-rod test at 24 rpm, motility in the open-field test, anxiety in the elevated plus-maze test) in Zurich developed wild-type adult mice (WT, controls of normal PrP(C) expression), in knockout (KO) mice (Prnp(0/0), with no PrP(C) expression), and in PrP(C) overexpressing Tg-20 mice. After 8 min in the rota-rod test, Tg-20 animals presented significantly fewer falls (1.08+/-1.56 falls) than both WT (7.27+/-4.36) and KO (7.6+/-6.15) mice (p<0.01). In the open field test, Tg-20 animals showed significantly increased motility [rearing=23.4+/-7.85, crossing=97.30+/-32.11) when compared with KO mice (rearing=5.45+/-3.69 and crossing=59.73+/-15.43) or WT mice (rearing=6.5+/-20.23 and crossing=45.18+/-20.33) (p<0.01). In the elevated plus-maze test, Tg-20 mice showed less anxiety (head projections=7.3+/-1.62) when compared with WT animals (3.38+/-0.67) (p<0.05). Moreover, KO mice spent more time in the centre of the plus maze (37.80+/-5.57 s) than did WT mice (22.57+/-3.82) (p<0.05). PrP(C) overexpressing mice evoked increased motility, less anxiety, and increased equilibrium when compared with WT control animals in the behavioural protocols used. KO animals also tended to evoke fewer anxiety-related responses in the elevated plus-maze test. These findings indicate that the levels of PrP(C) in adult life are associated with possible changes in motility, anxiety, and equilibrium.     

Impact of immediate and delayed light activation on self-polymerization of dual-cured dental resin luting agents

This study investigated the impact of immediate and delayed light activation on self-polymerization of a model dual-cured luting agent. The material presented the following components: base paste – 2,2-bis[4-(2-hydroxy-3-methacryloxyprop-1-oxy)phenyl]propane/triethylene glycol dimethacrylate (TEGDMA), camphorquinone, dimethyl-p-toluidine, butylated hydroxytoluene (BHT), glass fillers; catalyst paste – bisphenol-A ethoxylated dimethacrylate/TEGDMA, benzoyl peroxide, BHT, fillers. The pastes were mixed and seven polymerization scenarios tested: immediate light activation using low (5 J cm^?2) or high (20 J cm^?2) energy dose; delayed light activation (after 2 min – short delay) using low or high dose; delayed light activation (after 10 min – long delay) using low or high dose; and self-polymerization only. The degree of conversion (DC) and rate of polymerization (R_p) were evaluated for 30 min by real-time infrared spectroscopy. The lowest DC was detected for the self-polymerized and immediate–low dose groups, whereas the immediate–high dose and short delay–high dose groups showed the highest values. For the self-polymerized and immediate–high dose samples, R_p^max was detected after approximately 7 s, whereas this took approximately 14 s for the immediate–low dose group. R_p^max for the immediate–high dose group was higher than for the self-polymerized sample, which in turn was higher than for the immediate–low dose group. R_p^max for the short delay groups was higher than for the long delay groups. In conclusion, the extent of self-polymerization was influenced by the light dose reaching the material, which was dependent on high radiant exposure for optimal polymerization and the moment at which the light was applied; the short delay increased the DC for lower doses, while also generally decreasing the R_p for all scenarios.     

Clonality analysis of giant cell lesions of the jaws

Despite the importance of clonality to understand the pathogenesis and progression of tumors, it has not been investigated yet in giant cell lesions of the jaws. The aim of this study was to analyze the clonality of peripheral giant cell lesions (PGCL) and central giant cell lesions (CGCL) of the jaws. Six samples of PGCL and 5 samples of CGCL were analyzed in this study using the polymorphic human androgen receptor locus (HUMARA) assay. Three out of the 5 samples of the CGCL and 3 out of 6 samples of PGCL exhibited a monoclonal pattern. Our findings demonstrate that some giant cell lesions of the jaws are clonal, which indicate that these lesions may have a common genetic mechanism of development. Further studies are necessary to better elucidate the molecular mechanisms involved in the pathogenesis of such lesions.     

E-cadherin abnormalities resulting from CPG methylation promoter in metastatic and nonmetastatic oral cancer

BACKGROUND: This study aims to compare the alterations in the methylation profiles of E-cadherin in oral cancer, especially in tumors with lowest metatastic potential. METHODS: Nine oral verrucous carcinomas (VCs), 20 oral well-differentiated squamous cell carcinomas without lymph node involvement (SCC-pN0), and 17 with lymph node involvement (SCC-pN+) were analyzed using methylation-specific polymerase chain reaction and immunohistochemical expression of E-cadherin gene. RESULTS: The immunohistochemical expression of E-cadherin in VC was significantly higher (p = .016) when compared with SCC-pN0 and SCC-pN+ groups. The E-cadherin gene methylation was not correlated with its abnormal immunohistochemical expression in VC and SCC-pN0. All tumors of the SCC-pN+ group with unmethylated E-cadherin gene showed significant loss of E-cadherin immunoexpression (p = .044). CONCLUSIONS: The E-cadherin gene methylation presence in tumors with lowest invasive and metastatic potential, such as VC, suggests the early involvement of this epigenetic event in the multistep progression of the oral carcinogenesis.     

Adhesive performance of dentin bonding agents applied in vivo and in vitro. Effect of intrapulpal pressure and dentin depth

The purpose of this study was to evaluate the influence of intrapulpal pressure and dentin depth on bond strengths of an etch-and-rinse and a self-etching bonding agent to dentin in vitro and in vivo. Twenty-four pairs of premolars were randomly divided into four groups (n = 6) according to the dentin bonding agent, Single Bond and Clearfil SE Bond, and intrapulpal pressure, null or positive. Each tooth of the pair was further designated to be treated in vivo or in vitro. The intrapulpal pressure was controlled in vivo by the delivery of local anesthetics containing or not a vasoconstrictor, while in vitro, it was achieved by keeping the teeth under hydrostatic pressure. Class I cavities were prepared and the dentin bonding agents were applied followed by incremental resin restoration. For the teeth treated in vitro, the same restorative procedures were performed after a 6 month-storage period. Beams with 1 mm(2) cross-sectional area were prepared and microtensile tested. Clearfil SE Bond was not influenced by any of the variables of the study, while bond strengths produced in vitro were significantly higher for Single Bond. Overall, lower bond strengths were produced in deep dentin, which reached statistical significance when Single Bond was applied under physiological or simulated intrapulpal pressure. In conclusion, in vitro bonding may overestimate the immediate adhesive performance of more technique-sensitive dentin bonding systems. The impact of intrapulpal pressure on bond strength seems to be more adhesive dependent than dentin morphological characteristics related to depth.     

Effect of indomethacin-loaded nanocapsules incorporation in a dentin adhesive resin

Clinical Oral Investigations - The aim of this study was to produce indomethacin-loaded nanocapsules (IndOH-NCs) and evaluate the influence of their incorporation into an adhesive resin....