The study was conducted in vitro with human breast cancer cells BCaP-37, to determine the effects of selenium, vitamin A, vitamin E and a combination of these three nutrients on cell proliferation and cellular nucleic acid content. Selenium as sodium selenite had two phases of effect on cancer cell proliferation: the low concentrations of selenium (less than 5 ?M) stimulated cell growth and increased the cellular nucleic acid content; the high concentrations (more than 5 ?M) depressed cell growth and reduced the cellular nucleic acid content with dose-dependence. Vitamin A acetate inhibited cancer cell growth significantly, but vitamin A acid inhibited to some extent, and was less effective than vitamin A acetate. Vitamin E had less inhibitory effect compared to vitamin A acetate and the inhibitory percentages were lower than 40% in all treatment groups. Combination of selenium (5 ?M) and vitamin E (20mg/L) or selenium and vitamin A acetate (2mg/L), no synergism for the reduction of the contents of cellular nucleic acids (DNA and RNA) were observed. The combination of selenium, vitamin A acetate and vitamin E at such levels reduced cellular DNA and RNA contents obviously; RNA content was significantly lower than any other treatment group and was reduced synergis-tically. It was indicated that the combination of selenium, vitamin A acetate, vitamin E was synergistic for inhibition of cell proliferation. Results also showed the reversible tendency in the inhibition of cell proliferation by combination of these three nutrients. It was suggested that combination of selenium, vitamin A and E might be benificial for the prevention and adjuvant treatment of human breast cancer.

BACKGROUND:In clinical application,the therapeutic effect of transcranial magnetic stimulation depends on the ability to accurately target the areas of the brain that need to be stimulated.In recent years,with the development of neuronavigation systems,mobile augmented reality technology,and the new methods of processing magnetic resonance imaging(MRI)data,the accuracy of stimulus target localization and the optimization of target selection are expected to improve further. OBJECTIVE:To review the principle of MRI-based image navigation and its application in transcranial magnetic stimulation and summarize the roles of different modal MRI data analyses in guiding the selection of target areas for transcranial magnetic stimulation. METHODS:An online computer search for relevant literature was performed in PubMed,CNKI database and WanFang database,with the keywords"transcranial magnetic stimulation,coil positioning,neuronavigation,augmented reality,magnetic resonance,theory."Finally,63 documents were included for review. RESULTS AND CONCLUSION:Among the traditional methods of positioning transcranial magnetic stimulation coils,the"5 cm rule"and the international electroencephalogram 10-20 positioning method are the most commonly used.These methods have the advantages of simplicity and economy,but they rely too much on the operator's experience and there were technical differences between operators.The neuronavigation system,which is based on stereotactic technology,is the guiding method for positioning transcranial magnetic stimulation coils with the highest visual degree and accuracy.It achieves visual positioning through MRI data acquisition,3D brain reconstruction,head model registration and stereogeometric positioning.It has high application value in clinical treatment and scientific research,but it cannot be promoted in medical institutions due to its high cost.For various medical institutions,mobile augmented reality is a cost-effective and efficient alternative to the neuronavigation system,which achieves visual positioning of brain tissue under the scalp through MRI data acquisition,2D/3D image construction,virtual image and real brain image superposition.It has the advantages of directly visualization and low cost,and is expected to be popularized and applied in primary medical units.Although the superiority of clinical efficacy of visual coil positioning over the electroencephalogram 10-20 localization strategy has not yet been fully demonstrated,with the progress of brain MRI data analysis,visual positioning is expected to further optimize the target selection strategy of transcranial magnetic stimulation therapy and to improve the response rate and individuation degree of transcranial magnetic stimulation treatment.This is a promising and challenging research direction in the future.