Longitudinal study on the effect of oral hygiene measures on the salivary count of microbial species with cariogenic potential

The effect of oral hygiene education measures and professional tooth cleaning on the salivary levels of microbial species with high cariogenic potential (i.e. Streptococcus mutans, Lactobacillus spp. and Candida albicans) was evaluated at different time points. At time 0, high salivary carriage rates were recorded in the study group (n=30). Fifty percent of the subjects harbored all three species in their saliva, 27% harbored 2 species, and 23% only one species. At 3 months after oral hygiene measures, a statistically significant reduction was observed in salivary count of S. mutans and Lactobacillus spp. The percentage of subjects harboring all three species was also highly reduced, along with an overall improvement of clinical and risk factors parameters. At 8 months after oral hygiene measures, S. mutans and Lactobacillus spp. load was still statistically lower than that recorded at time 0, although an increment in bacterial load and a partial worsening of clinical and risk factors parameters were observed. S. mutans count in saliva inversely correlated with salivary pH, while it positively correlated with C. albicans salivary levels. The results obtained suggest that strengthening of the motivation and administration of oral hygiene instructions and professional tooth cleaning every 6-8 months, might be necessary to control salivary levels of cariogenic species.

A 12 000-rad whole-genome radiation hybrid panel in sheep: application to the study of the ovine chromosome 18 region containing a QTL for scrapie susceptibility

Whole-genome radiation hybrid (RH) panels have been constructed for several species, including cattle. RH panels have proven to be an extremely powerful tool to construct high-density maps, which is an essential step in the identification of genes controlling important traits, and they can be used to establish high-resolution comparative maps. Although bovine RH panels can be used with ovine markers to construct sheep RH maps based on bovine genome organization, only some (c. 50%) of the markers available in sheep can be successfully mapped in the bovine genome. So, with the development of genomics and genome sequencing projects, there is a need for a high-resolution RH panel in sheep to map ovine markers. Consequently, we have constructed a 12 000-rad ovine whole-genome RH panel. Two hundred and eight hybrid clones were produced, of which 90 were selected based on their retention frequency. The final panel had an average marker retention frequency of 31.8%. The resolution of this 12 000-rad panel (SheepRH) was estimated by constructing an RH framework map for a 23-Mb region of sheep chromosome 18 (OAR18) that contains a QTL for scrapie susceptibility.