Backward masking and the central performance drop

AbstractKehrer [Spatial Vision 2 (1987) 247] found that texture discrimination performance sometimes peaks in the parafovea rather than at the fovea, and he referred to this phenomenon as the central performance drop (CPD). Kehrer used a backward mask to limit performance and Morikawa [Vision Res. 40 (2000) 3517] argued that in some cases the temporal aspects of the backward mask may be critical to the emergence of the CPD. In one experiment Morikawa showed that the CPD does not emerge when a simultaneous noise-mask (different from the mask used by Kehrer) is used to limit performance. In another experiment Morikawa showed that unmasked texture displays comprising short lines do not elicit the CPD. In both cases, changes in the temporal aspects of the texture displays were accompanied by changes in the spatial structure of the mask or stimulus. For the spatio-temporal theory of the CPD to be sustained one would have to show that noise masks elicit a CPD when used as backward masks and that the short-line textures elicit a CPD when followed by backward masks. Our evidence provides little if any support for either of these predictions. Furthermore, an analysis of a simple filter-rectify-filter model of texture segmentation shows that a greatly attenuated CPD is to be expected when a noise mask is used as a source of spatial noise

Relationship between -889 C/T polymorphism in interleukin-1A gene and risk of chronic periodontitis : evidence from a meta-analysis with new published findings

Periodontitis results from an inflammatory response caused by accumulative microorganisms in periodontal sites. Several factors are involved in pathogenesis of periodontitis, for example the -889 C/T polymorphism in interleukin-1A gene. This study aimed to evaluate the relationship between this polymorphism and risk of development of chronic periodontitis by a meta-analysis based in new published findings. Thereunto a review in literature was performed in the electronic biomedical and education databases (Cochrane Library, Google Scholar, MEDLINE and PubMed) to studies published before August 2, 2015, the abstracts were evaluated and the data extraction performed by two calibrated examiners. The calculations of the meta-analysis were obtained through statistical software Review Manager version 5.2 with calculation of Odds Ratio (OR), heterogeneity (I²) and Funnel plots with P <0.05. In overall, twenty-one case/control studies were selected with 2,174 patients with chronic periodontitis and 1, 756 controls. The meta-analysis showed T allele was associated with chronic periodontitis (OR = 1.22, 95% CI: 1.09, 1.36, P = 0.0004) with decreased value to heterogeneity (I² = 15%, P = 0.28). TT genotype was associated to patients with chronic periodontitis (OR = 1.40, 95% CI: 1.07, 1.83, P = 0.01). No publication bias was found in this meta-analysis by asymmetry in Funnel plots. This meta-analysis with 2,174 patients with chronic periodontitis and 1, 756 controls evidenced the -889 C/T polymorphism is associated to risk of development of chronic periodontitis with no significant value to heterogeneity to allelic evaluation

One or two ligatures inducing periodontitis are sufficient to cause fatty liver

Periodontitis is a chronic disease that due to an intense inflammatory response triggers systemic changes such as hepatic alterations. This study aimed to compare hepatic damage in rats that received experimental periodontitis at one or two periodontal sites with ligatures. Eighteen rats were separated into three groups: control, without ligature; periodontitis 1, with one ligature; and periodontitis 2, with two ligatures. The following parameters were assessed: gingival bleeding index, probing pocket depth, tooth mobility, alveolar bone loss, malondialdehyde (MDA) and myeloperoxidase (MPO) activity in periodontal tissue; histopathological evaluation of hepatic tissue (steatosis score); glutathione levels (GSH), MDA, MPO, cholesterol and triglycerides in the liver; and serum levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST). Periodontal evaluation data showed that the periodontitis model worked well. The groups with periodontitis did not differ significantly in relation to MPO activity and MDA levels in the gingival samples, but they were significantly different when compared with the control group. Steatosis was observed in the histological analysis of the groups with periodontitis, but between the periodontitis groups, two ligatures did not cause increase in steatosis score. The levels of GSH, MDA, total cholesterol and triglycerides in the hepatic tissue were not altered between groups with periodontitis, but they showed significant differences in comparison with the control group. The activity of MPO in hepatic tissue and serum levels of AST and ALT did not present significant difference among the three groups. In conclusion, our results demonstrated that one or two ligatures inducing periodontitis were both sufficient to cause fatty liver. Steatosis caused by two ligatures did not present larger extension and severity than steatosis caused by one ligature

Biological Effects of Medicinal Plants on Induced Periodontitis: A Systematic Review

Objective. The aim of this systematic review was to investigate the advances in the study of medicinal plants and their biologic effects on periodontitis in animal models. Study Design. A systematic search was conducted by three independent researchers, who screened articles published up to March/2016, to identify the studies that contained sufficient and clear information on the association of the medicinal plants and periodontitis in murine models. The searches were performed using PubMed, Cochrane, and Science Direct databases. Results. After a critical analysis of titles and abstracts, 30 studies were finally eligible for analysis. The studies presented a great diversity of the experiment designed regarding the methods of induced periodontitis and the evaluation of the medicinal plants efficacy. None of the studies described the possible toxic effects associated with the administration of the plant material to animals and whether they could prevent damage to organs caused by systemic effect of induced periodontitis. Gel-based formulations containing plant substances are seen as an interesting strategy to treat periodontitis. Conclusions. In this systematic review, the state-of-the-art knowledge on the medicinal plants and the induced periodontitis was critically evaluated and discussed from the experiment designed to the possible clinical application

Periodontitis causes abnormalities in the liver of rats

Periodontitis not only causes injury to the periodontium, but also damages other tissues such as: articulate, renal, cardiac, and hepatic. The objective of this study was to investigate periodontitis induced alterations in liver function and structure using an experimental model.Twenty female rats (Rattus norvegicus) were allocated into two groups: control and periodontitis. Gingival bleeding index and oxidative stress parameters and specific circulating biomarkers were measured. Immunohistochemistry was carried out using alkaline phosphatase (AlkP) staining of the liver. Hepatic tissues, cytokines, and lipid contents were measured. Histopathologic evaluation of the liver was carried out using light and electron microscopy.Liver histopathologic and immunohistochemistry assessment showed increase in steatosis score, and presence of binucleate hepatocytes and positive cells for AlkP in periodontitis versus control group. Ultrastructural evaluation showed significant increase in size and number of lipid droplets (LD), distance between the cisterns of rough endoplasmic reticulum (RER), mitochondria size, foamy cytoplasm, and glycogen accumulation in the liver of the periodontitis group compared with the control group. In addition, plasma levels of AlkP, high‐density lipoprotein (HDL), triglycerides, and total cholesterol were also changed.Experimental periodontitis caused immunohistochemistry, histopathologic, ultrastructural, oxidative, and biochemical changes in the liver of rats.903295305CAPES - Coordenação de Aperfeiçoamento de Pessoal e Nível SuperiorCNPQ - Conselho Nacional de Desenvolvimento Científico e Tecnológico455104/2014-0Não te