Propolis, the resinous hive product collected by bees, is important in the defense of the hive. The effects of propolis on growth and glucosyltransferase activity of Streptococcus sobrinus 6715, Streptococcus mutans PS14 and Streptococcus cricetus OMZ61 in vitro, and on dental caries in rats infected with S. sobrinus 6715 were investigated. Propolis had antimicrobial activity against S. sobrinus, S. mutans and S. cricetus, and inhibited both water-insoluble glucan synthesis and glucosyltransferase activity. In rats inoculated with S. sobrinus, about half of their fissures were carious, while dental caries was significantly less (p = 0.01) in rats given propolis. Dental caries was markedly decreased by the multiple actions of propolis which had antimicrobial activity, inhibited water-insoluble glucan synthesis, and inhibited glucosyltransferase activity. No toxic effects of propolis on the growth of rats were observed under experimental conditions in this study. These results suggest that propolis can control dental caries in the rat model system.

Both tooth enamel ESR and lymphocyte cytogenetics are useful measures for individual biodosimetry of acute radiation exposure, even half a century after the exposure occurred.

No abstract

The method of electron paramagnetic resonance (EPR) dosimetry was applied to the enamel of the teeth extracted from the residents of the Dolon and Bodene settlements of the Beskaragay district, which is the area adjacent to the radioactive fallout of the most contaminating nuclear test of 1949. The individual accidental radiation doses due to the fallout were obtained from the amplitude of the radiation induced EPR signal from the CO2- radical using the calibration method, after determining the parameters of EPR measurements to obtain the best reproducibility of the signal intensities. It was shown that after subtracting the natural background dose from the total absorbed dose obtained by EPR the residents of Dolon and Bodene received accidental radiation doses up to 356 mGy with an average value of 74.1+/-45.5 mGy before 1949 while the younger population received up to about 100 mGy with an average value of 11.5+/-37.7 mGy.

The objective of the Third International Intercomparison on EPR Tooth Dosimetry was to evaluate laboratories performing tooth enamel dosimetry <300 mGy. Final analysis of results included a correlation analysis between features of laboratory dose reconstruction protocols and dosimetry performance. Applicability of electron paramagnetic resonance (EPR) tooth dosimetry at low dose was shown at two applied dose levels of 79 and 176 mGy. Most (9 of 12) laboratories reported the dose to be within 50 mGy of the delivered dose of 79 mGy, and 10 of 12 laboratories reported the dose to be within 100 mGy of the delivered dose of 176 mGy. At the high-dose tested (704 mGy) agreement within 25% of the delivered dose was found in 10 laboratories. Features of EPR dose reconstruction protocols that affect dosimetry performance were found to be magnetic field modulation amplitude in EPR spectrum recording, EPR signal model in spectrum deconvolution and duration of latency period for tooth enamel samples after preparation.