[Rasch analysis of the Chinese Version of the Low Vision Quality of Life Questionnaire]

Objective: To investigate the unidimensionality, reliability and validity of the Chinese version of the Low Vision Quality of Life Questionnaire (CLVQOL) on the basis of Rasch analysis. Methods: All participants completed the CLVQOL. The psychometric properties of the CLVQOL were tested using Rasch analysis,including the unidimensionality,person separation index (PSI),person reliability (PR), infit mean square MNSQ and differential item functioning (DIF). Results: One hundred and forty seven residents,including 58 males (39.46%) and 89 females (60.54%),were enrolled. The mean age of the participants was (67±10) years old. The CLVQOL had 4 original scales. The first scale was found to be multidimensional and was subsequently divided into 2 scales. A new 5-scale CLVQOL was then developed, and all 5 scales were shown to be unidimensional. All PSIs exceeded 2,and all PRs exceeded 0.8,indicating the favorable discriminant ability of the questionnaire. Notable DIF was not found for any item across different age or gender subgroups. Conclusions: A Rasch model can be used in improving the rating questionnaires for evaluating vision-related quality of life (VRQoL). All 25 items demonstrated an acceptable fit in Rasch analysis,and a new 5-scale CLVQOL was developed.(Chin J Ophthalmol, 2019, 55: 582-588).

The cell death and DNA damages caused by the Tet-On regulating HSV-tk/GCV suicide gene system in MCF-7 cells

Ganciclovir (GCV) affects the molecular mechanism of cell death and DNA damage by the rAAV (recombinant adeno-associated virus)-mediated Tet-On/HSV-tk/GCV suicide gene system in human breast cancer cell line MCF-7. A rAAV/TRE/Tet-On/HSV-tk combining a Tet-On regulating system and a suicide gene HSV-tk was used to transfect human breast cancer cell line MCF-7, and therapeutic effects on this system were studied. Afterwards, we used RT-PCR, western blotting, and a modified comet-assay to explore the potential mechanism of the HSV-tk/GCV suicide gene system in breast cancer treatments. MTT assay has shown that the cell number of GCV+rAAV+Dox group was significantly decreased compared with that of other groups after treatment and flow cytometric analysis detected that there was a substantial increase of S phase cells in this group, which means the HSV-tk/GCV suicide gene system probably works on the cell cycle. RT-PCR detected the expression level of p21 increased and PCNA had an opposite trend. Western blotting detected the protein expression of p21 and p53 increased and PCNA, CDK1, cyclin B decreased in GCV+rAAV+Dox group. The modified comet-assay shown that the very small extra fragments generated by the GCV+rAAV+Dox group treatment are visible as a small cloud extending from the comet in the direction of electrophoresis. The therapeutic mechanism of the HSV-tk/GCV suicide gene system on human breast cancer cell line MCF-7 is probably by upregulating the expression of p21 through a p53-dependent DNA damage signalling pathway, leading the decrease of protein expression of PCNA, cyclin B, CDK1 in MCF-7 cells and promoting the cell cycle arrest at G1/S phase. In summary, the HSV-tk/GCV suicide gene system arouses the death of MCF-7 cells from blocking the cell cycle and DNA damage.