The goal of these experiments was to investigate further the relationship between DNA double-strand breaks and cell killing in human tumor cells, first by comparing different cell lines, and second by radiomodification studies. Field-inversion gel electrophoresis was used to quantify double-strand breaks. Two subclones of the radioresistant human squamous cell carcinoma line SQ20B (SQD9 and SQG6) were compared. These subclones differed in DNA index by a factor of 1.7 but showed the same resistance to radiation as cells of the parental cell line. It was found that, although induction of DSBs was not significantly different in the two cell lines, the t1/2 of the fast component of repair was significantly shorter for SQD9 cells, leading to greater overall repair which was not reflected in increased survival. Caffeine and cysteamine were tested as modifiers of radiosensitivity, using the radioresistant SQ20B line and the radiosensitive SCC61 cell line. No effect of caffeine was seen when the drug was present only during irradiation. Postirradiation incubations with caffeine, however, resulted in a dose reduction factor greater than 2.0 in cell survival for both cell lines. In contrast, induction of DSBs was reduced by caffeine, and no effect on DSB repair was observed. Cysteamine led to a dose protection factor greater than 1.8 in cell survival in both cell lines. A reduction in induced DSBs was found at high doses corresponding approximately with the increase in cell survival. Over the same (low) dose range, however, the correlation between DSB induction and cell killing was poor. These data indicate that DSB induction does not correlate well with cell killing either for different cell lines, for radiochemical modification (cysteamine) or for some other types of modification (caffeine).
Objective
To compare the management of large ureteric stones (>10 mm) with ureterorenoscopy (URS) and laser or pneumatic lithotripsy, and their associated costs.
Patients and methods
Our prospective study followed the tenets of the Declaration of Helsinki and included 101 patients with large mid-ureteric stones eligible for URS and lithotripsy, and was conducted between January 2018 and August 2019. Patients were randomly divided into two groups: Group 1 had laser lithotripsy, while the Group 2 had lithotripsy using a pneumatic energy source.
Results
Operative time was significantly longer in cases using pneumatic lithotripsy (
P
< 0.001). The stone-free rate (SFR) on the first postoperative day was 94% and 92.5% for laser and pneumatic lithotripsy respectively, and there were no statistically significant differences in terms of early (day 1) or late (day 30) SFRs between the groups. Complications were classified according to the Clavien–Dindo Grading System, all complications were Grade
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