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

BACKGROUND: 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. MATERIAL AND METHODS: 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). RESULTS: 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. CONCLUSION: 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.

Mutual information content of homologous DNA sequences

The necessary information to reproduce and keep an organism is codified in acid nucleic molecules. Deepening the knowledge about how the information is stored in these bio-sequences can lead to more efficient methods of comparing genomic sequences. In the present study, we analyzed the quantity of information contained in a DNA sequence that can be useful to identify sequences homologous to it. To reach it, we used signal processing techniques, specially spectral analysis and information theory.