ABSTRACT
OBJECTIVE: To explore the effect of~(56)Fe~(17+)heavy ion on the expression of phosphorylated histone H2AX( γH2AX) of human lymphccytes. METHODS: The Epstein-Barr virus transformed human B lymphocyte cell lines( PengEBV) were selected and exposed to~(56)Fe~(17+)heavy ion at irradiation dose of 0. 0( control group),0. 1,0. 3,0. 5,0. 7,1. 0 and 2. 0 Gy,respectively,with the dosing rate of 0. 23-0. 55 Gy / min. Flow-cytometry was used to detect the changes of expression of γH2AX at time points of 0,2,4,8,48 and 72 hours after irradiation. RESULTS: The expression of γH2AX showed interaction existed between radiation dose and the treatment time after radiation( P < 0. 01). Compared with the control at the same time points,the expression of γH2AX increased at the dose of 0. 3-2. 0 Gy and the time points of 2-72hours( P < 0. 05). The expression of γH2AX at the dose of 0. 3-2. 0 Gy and time points of 8-72 hours was lower than those at the same dose and time points of 2 and 4 hours( P < 0. 05). When the dose was at 0. 5,1. 0 or 2. 0 Gy,the expression of γH2AX decreased with the increasing time of exposure in 72 hours( P < 0. 05). At the dose of 0. 0-1. 0 Gy and the time points of 2-4 hours,the expression of γH2AX increased with the increasing dose of irradiation( P < 0. 01). CONCLUSION: The expression of γH2AX in Peng-EBV cells shows a dose-response relationship within 2-4 hours after 0. 0-1. 0 Gy irradiation of~(56)Fe~(17+).
ABSTRACT
Objective To use high frequency ultrasound for scanning the lower uterine segment during the third trimester of scar uterus pregnancy cases were selected. Transabdominal ultrasound scan was done for the fetus between 36th and 40th week of pregnancy, and then the transducer was switched to a high frequency of 7.5-12 MHz to observe the lower uterine segment. The scan results were compared with the obserbations of in complete rupture of lower uterine segment and defective scars in the repeated caesarean section. Results Three types of high frequency ultrasound images were found for the lower uterine segment during the third trimester of scar uterus pregnancy: efficacies of truncation sign (608%,8/118), rat tail sign (44.1%,52/118), and homogeneous echoes (49.1%.58/118). The diagnosis efficacies of truncation sign for incomplete rupture of uterus, rat tail sign for defective scars, and homogeneous echoes for intact cadsarean scars were significantly higher than those of the other two types (X2 valued 20.42, 19.03, and 33.08, respectively, P<0.001). The diagnostic sensitivity, positive predictive value and negative predictive value of the truncation sign were 80.0%, 96.5%, 50.0%, and 99.0%; those of the rat tail sign were 70.0%, 73.8%, 67.3%, and 76.2%; and those of homogeneous echoes were 72.9%, 74.1%, 74.1%, and 73.3%, respectively. Conclusion High frequency ultrasound scan can display the changes of the scars on the lower uterine segment, and may serve as an effective method to diagnose incomplete rupture of uterus, defective and intact scars in the third trimester pregnancy of a caesarean-scarred uterus. To avoid uterine rupture, vaginal trail of labor should be carefully chosen for patients shoeing truncation sign or rat tail sign.