Time warping of evolutionary distant temporal gene expression data based on noise suppression

<p>Abstract</p> <p>Background</p> <p>Comparative analysis of genome wide temporal gene expression data has a broad potential area of application, including evolutionary biology, developmental biology, and medicine. However, at large evolutionary distances, the construction of global alignments and the consequent comparison of the time-series data are difficult. The main reason is the accumulation of variability in expression profiles of orthologous genes, in the course of evolution.</p> <p>Results</p> <p>We applied Pearson distance matrices, in combination with other noise-suppression techniques and data filtering to improve alignments. This novel framework enhanced the capacity to capture the similarities between the temporal gene expression datasets separated by large evolutionary distances. We aligned and compared the temporal gene expression data in budding (<it>Saccharomyces cerevisiae</it>) and fission (<it>Schizosaccharomyces pombe</it>) yeast, which are separated by more then ~400 myr of evolution. We found that the global alignment (time warping) properly matched the duration of cell cycle phases in these distant organisms, which was measured in prior studies. At the same time, when applied to individual ortholog pairs, this alignment procedure revealed groups of genes with distinct alignments, different from the global alignment.</p> <p>Conclusion</p> <p>Our alignment-based predictions of differences in the cell cycle phases between the two yeast species were in a good agreement with the existing data, thus supporting the computational strategy adopted in this study. We propose that the existence of the alternative alignments, specific to distinct groups of genes, suggests presence of different synchronization modes between the two organisms and possible functional decoupling of particular physiological gene networks in the course of evolution.</p

Survival and Factors Associated with Failure of Pulpectomies Performed in Primary Teeth by Dental Students

Abstract Although endodontic treatment is widely recommended for compromised dental pulp, there is no information regarding the factors associated with failures in primary teeth. The aim of this study was to evaluate the survival and factors associated with failure of pulpectomies performed in primary teeth by dental students. The sample comprised patients treated at a University Dental Service and required endodontic treatment in primary teeth. The study investigated treatment-related variables and patient factors potentially associated with treatment failure. Pulpectomy survival was analyzed by Kaplan-Meier estimator followed by log-rank test (p<0.05). The analysis included 81 pulpectomies performed in 62 children (5.6±1.5 years). The survival reached 62.9% up to 12 months follow-up. Most failures occurred in the first 3 months (p<0.001). Teeth with carious lesions at the start of treatment presented more failures than those with restorations or history of trauma (p=0.002). The survival of endodontically treated teeth restored with composite was higher than the ones filled with GIC (p=0.006). Pulpectomy performed in two or more sessions resulted in more failures (p=0.028). Patients presenting gingivitis had more failures in the endodontic treatment (p=0.022). The failures of root canal treatment in primary teeth were more prone to occur in a short time and when the treatment was performed in teeth presenting carious lesions. The use of composite instead of GIC increased the survival of pulpectomies. Repeated sessions for endodontic treatment and lack of oral hygiene habits had a negative effect on the results