Objective To determine the optimized fractionated radiation schedule by comparing the dose-response relationship between different fractionated radiation schedules with a total dose of 40 Gy or 60 Gy in subclinical breast tumor.Methods Balb/c nude mice bearing subclinical human breast cancer (injected subcutaneously into the hind legs with 1.5 × 105 or 3.1 × 105 exponentially growing MCF-7 cells) were assigned randomly to blank control group (without radiation),conventionally fractionated radiation group (200 cGy,once daily,10 times/week),hyperfractionated radiation group (160 cGy,twice daily with an interval of 6 h,5 times/week),first hypofractionated radiation group (300 cGy,once daily,5 times/ week),and second hypofractionated radiation group (400 cGy,once every other day,3 times/week) ;the total dose was 40 Gy or 60 Gy.The measurement indices were tumor formation rate,short-term tumor control rate,long-term tumor control rate,the time of tumor recurrence,and the maximum diameter of the bottom of tumor.The observation lasted 24 weeks.Data were compared between these groups by chi-square test.Results With a total dose of 40 Gy (the number of injected cells was 1.5 × 105,the tumor formation rate of the blank control group was 2/8),hyperfractionated radiation was the optimized schedule.With a total dose of 60 Gy (the number of injected cells was 3.1 × 105,the tumor formation rate of the blank control group was 11/11),the first hypofractionated radiation (300 cGy,once daily,5 times/week) was the optimized schedule (P =0.001);the short-term and long-term tumor control rates of the conventionally fractionated radiation group,hyperfractionated radiation group,second hypofractionated radiation group,and first hypofractionated radiation group were 0/0 (tumor formation rates:8/8 and 8/8),50％/25％ (tumor formation rates:4/8 and 6/8),25 ％/25 ％ (tumor formation rates:6/8 and 6/8)),and 67 ％/67 ％ (tumor formation rates:4/12 and 4/12),respectively.Conclusions The optimized fractionated radiation schedule for subclinical breast cancer and its total dose vary with the number of injected tumor cells.When the tumor formation rate is 100％,hypofractionated radiation (300 cGy,once daily,5 times/week) is the optimized schedule in terms of long-term tumor control.

Objective To investigate the serum vitamin and trace element levels in children with short stature and their correlation with bone age. Methods Levels of serum VA and VD, and trace elements Ca, Fe, Zn, Mg, Cu, Pb and Cd were measured in 322 children who were referred for height consultation. Bone ages were evaluated and the correlation between bone age and serum vitamin and trace element levels was analyzed. Results The VA and VD deficiency rates of these 322 children were 22.05% and 34.16%, respectively. The deficiency rates of trace elements Ca, Fe and Zn were14.29%, 21.43% and 6.83%, respectively. The Pb excess rate was as high as 42.55%. The rates of bone age (BA) retardation in Group Ⅰ (short) and Group Ⅱ (slightly short) were 49.38% and 37.57%, respectively, which was significantly higher than that of Group Ⅲ (normal). The Ca level of BA retardation children was lower than that of the normal BA children in Group I. The VD level of BA retardation children was lower than that of the normal BA children in Group Ⅱ. BA was negatively correlated with VD, Ca, and Cu levels in children (r=-0.241; r=-0.136; r=-0.162), and positively correlated with Fe (r=0.286) . Conclusion There were significant abnormalities of vitamins and trace elements in short children. Children's bone age had a certain correlation with serum vitamin D, calcium, copper, and iron levels. Serum vitamin and trace element levels in children should be monitored to guide a reasonable diet to better promote child growth and development.