Investigation on validity period of glassware containing sterilized oral small instruments after disinfection unsealing / 重庆医学

Objective To study the validity period of glassware containing sterilized oral instruments after disinfection unsea‐ling .Methods Fifteen stomatology consulting rooms were selected on the normal working day by using the convenience sampling method .2 sterilized glass containers (filled with sterilized instruments) were selected in each room .The samples were collected at 4 ,8 ,24 ,48 ,72 ,96 ,120 ,144 ,168 h during the use process after unsealing the containers and the growth situation of bacteria was carefully observed .Results Thirty glasswares had no bacterial growth at 4 ,8 ,24 ,48 h during the use process after unsealing ,only 3 bacteria grew in the sampling culture at 72 h ,the differences had no statistical significance compared with at 4 ,8 ,24 ,48 h (P>0 .05);10 bacteria grew in the sampling culture at 96 h ,the differences had statistical significance compared with at 4 ,8 ,24 ,48 h (P<0 .05) .The validity period of glassware containing sterilized oral instruments after disinfection unsealing was 48 h .Conclusion The validity period of glassware containing sterilized oral instruments is 48 h after disinfection unsealing ,the extension of validity period can decrease the sterilization times ,reduce the equipment wastage and prolong the equipment service life .

Probe binding to host proteins: a cause for false positive signals in viroid detection by tissue hybridization.

Molecular hybridization assay, especially involving the use of tissues directly, has been developed as a rapid, simple and important technique for plant pathogen detection and/or gene expression analysis on a large scale. In theory, this method relies on the specific binding of a labeled probe to a target nucleotide sequence. However, occasional false positive reactions can pose a problem in its application and the cause is often not well understood. Here, we show that in tissue-printing hybridization to detect Peach latent mosaic viroid (PLMVd) strong signals could arise by interactions between the viroid probe and plant proteins. Such probe-protein interactions made it difficult to show significant correlations between viroid infection and the level of hybridization signals. These results challenge the traditional view that proteins may hamper PCR reactions but have no influence on molecular hybridization. They further demonstrate that such probe-protein interactions in a plant could compromise the quality of molecular hybridization assays for viroid detection. Our results uncovered an important source of false positive reactions in tissue-printing hybridization and suggest that specificity can be improved by removing proteins.