Effect of thimerosal on vaccine antigen activity and its mechanism / 中国生物制品学杂志

@#Abstract： Thimerosal is commonly used as a preservative in biological products，especially in vaccines. Although it has been removed from single ⁃ dose vaccines in most countries，thimerosal is still widely used in multi ⁃ dose vaccines at present. Thimerosal，as a component in vaccine preparation，should be compatible with other components，especially should not damage the activity of antigen. However，in recent years，many studies have reported that thiomersal can reduce the antigenicity and immunogenicity of vaccine antigens，especially protein antigens containing or rich in cysteine（Cys）， suggesting that the effect of thimerosal on vaccine antigen activity should be fully evaluated when it is used as a vaccine preservative. In this paper，the effects of thimerosal on antigenicity and immunogenicity of two inactivated vaccines and three recombinant protein vaccines and the possible mechanisms were reviewed，in order to provide reference for rational selection of vaccine preservatives.

Investigation on periodontal status of senior high school students in Dongcheng district of Beijing / 口腔疾病防治

Objective@#The aim of this study is to investigate the periodontal status of senior high school students in Dongcheng District, Beijing. @*Methods @#750 Beijing senior high school students were recruited in this study. The periodontal examination assessed the calculus, bleeding on probing, probing depth, and clinical attachment loss. The prevalences of gingivitis and periodontitis were assessed. @*Results @#A total of 73.5% of the subjects had gingivitis, the prevalences of gingivitis in male and female were 76.7% and 69.2% respectively. The prevalence of periodontitis was 10.9% in total, with 11.8% in male and 9.8% in female respectively.@*Conclusion @#The prevalence of gingivitis was high in senior high school students, and significantly higher in male. The prevalence of periodontitis was relatively low, and there was no difference in gender.

The effects of 240 g/L EDTA gel on the attachment and proliferation of human periodontal ligment cells onto the root surface of teeth with periodontitis / 实用口腔医学杂志

Objective:To study attachment and proliferation of human periodontal ligment cells(HPDLCs) on demineralized root surface of teeth with periodontitis following EDTA gel application. Methods:44 single-rooted teeth extracted because of severe periodontitis were treated by scaling and root planing(SRP). Then the fragments(5 mm?4 mm) of experimental surfaces were prepared. The fragments were randomly divided into four groups.The root surfaces in group 1,2,3 and 4 were treated by 240 g/L of EDTA gel for 2,3 and 4 min respectively or without treatment(control). Then 1?104 cells were seeded on the surface of each fragment and routinely cultured for 1,3 and 5 days respectively after seeding, the specimens were prepared for microscopic observasion, the cells on the root surfaces were counted. Moreover the other eight fragments were prepared for SEM observasion. Results:HPDLCs attached to and proliferated on all treated surfaces.Group 1, 2 and 3 presented significantly more cells on the root surfaces than the control group did at day 1,3 and 5. The cells on the root surfaces in group 2 and 3 were more than those in group 1 at day 1, 3 and 5. There was no evident difference between group 2 and 3 at any time. The root surfaces in group 2 and 3 had a fibrillar texture associated with an increased diameter of the exposed dentinal tubule openings.Smear layer were observed on root surfaces in group 1. Conclusion:EDTA gel(at 240 g/L) application may enhance attachment and proliferation on root surface of HPDLCs.