Objective:To investigate the impacts of the radiosensitivity of cell lines on a microdosimetric kinetic model (MKM) used in carbon-ion radiotherapy.Methods:The saturation-corrected specific energy ( ) of monoenergetic carbon ions was calculated using the Kiefer-Chatterjee (K-C) track structure model. Correction curve f(LET) was derived from experimental data on relative biological effectiveness (RBE) (RBE DSB-LET) defined based on the double-strand DNA break of the Chinese hamster ovary (CHO) and Fibroblast cell lines irradiated using carbon ions with varying linear energy transfer (LET) values. Then, based on the MKM, the D10-LET curves, as well as α and β databases, of the CHO and Fibroblast cell lines with varying radiosensitivity were determined. Results:Compared to the clinically applied MKM, the predicted D10 after correction while accounting for cell line radiosensitivity agreed better with experimental D10 values of the CHO and Fibroblast cell lines. Specifically, compared to experimental values in the literature, the D10 values calculated in the study and determined using the MKM showed mean squared errors (MSEs) of 0.04 and 0.71, for the CHO cell line and 0.35 and 0.55, respectively, for the Fibroblast cell line. For monoenergetic carbon ions with varying LET values, the calculated α and β values generally increased with cellular radiosensitivity. Conclusions:Incorporating cellular radiosensitivity into the MKM framework serves as a more specific method for RBE assessment while also providing a reference for advancing MKM applications and achieving the fine-scale calculations of RBE in carbon-ion radiotherapy.

Objective:To evaluate the feasibility and efficacy of our self-designed intelligent robot-assisted reduction system for fresh subtrochanteric fractures of the femur.Methods:A retrospective cohort study was conducted to include 10 patients with fresh subtrochanteric fracture of the femur who had been admitted to Department of Orthopedic Trauma, Beijing Jishuitan Hospital from January 2024 to July 2024. There were 7 males and 3 females with an age of (45.0±14.3) years and an interval from injury to surgery of (7.9±3.7) d. All the patients were treated by minimally invasive reduction which was assisted by our self-designed intelligent robot, and internal fixation with intramedullary nails. The operation duration, intraoperative reduction duration, intraoperative blood loss, and intraoperative fluoroscopy frequency were recorded. The reduction effect was evaluated by calculating the differences between preoperative planning and postoperative CT reconstruction (i.e., the differences in femoral shaft length and in rotation angle). The hip functional recovery was assessed by Harris hip function Scoring.Results:The mean operation time was 200.0 (161.3, 217.5) min, the reduction time (83.0±35.5) min, the intraoperative blood loss (290.0±110.1) mL, and the intraoperative fluoroscopy 18.5 (9.0, 19.3) times. In all patients, the difference in femoral shaft length was (2.4±1.4) mm, and the difference in rotation angle 5.1°±3.0°. All patients were followed up for (8.2±2.0)months. All the fractures got united at the last follow-up. Their Harris hip function score was (83.3±4.1) points.Conclusion:Our self-designed intelligent robot-assisted reduction system is feasible and effective in the surgery of fresh subtrochanteric fracture of the femur, because the robot system can complete the autonomous planning of reduction approaches before surgery and assist fracture reduction under real-time monitoring with three-dimensional images, leading to fine outcomes.

Objective:To investigate the impacts of the radiosensitivity of cell lines on a microdosimetric kinetic model (MKM) used in carbon-ion radiotherapy.Methods:The saturation-corrected specific energy ( ) of monoenergetic carbon ions was calculated using the Kiefer-Chatterjee (K-C) track structure model. Correction curve f(LET) was derived from experimental data on relative biological effectiveness (RBE) (RBE DSB-LET) defined based on the double-strand DNA break of the Chinese hamster ovary (CHO) and Fibroblast cell lines irradiated using carbon ions with varying linear energy transfer (LET) values. Then, based on the MKM, the D10-LET curves, as well as α and β databases, of the CHO and Fibroblast cell lines with varying radiosensitivity were determined. Results:Compared to the clinically applied MKM, the predicted D10 after correction while accounting for cell line radiosensitivity agreed better with experimental D10 values of the CHO and Fibroblast cell lines. Specifically, compared to experimental values in the literature, the D10 values calculated in the study and determined using the MKM showed mean squared errors (MSEs) of 0.04 and 0.71, for the CHO cell line and 0.35 and 0.55, respectively, for the Fibroblast cell line. For monoenergetic carbon ions with varying LET values, the calculated α and β values generally increased with cellular radiosensitivity. Conclusions:Incorporating cellular radiosensitivity into the MKM framework serves as a more specific method for RBE assessment while also providing a reference for advancing MKM applications and achieving the fine-scale calculations of RBE in carbon-ion radiotherapy.

Objective:To evaluate the feasibility and efficacy of our self-designed intelligent robot-assisted reduction system for fresh subtrochanteric fractures of the femur.Methods:A retrospective cohort study was conducted to include 10 patients with fresh subtrochanteric fracture of the femur who had been admitted to Department of Orthopedic Trauma, Beijing Jishuitan Hospital from January 2024 to July 2024. There were 7 males and 3 females with an age of (45.0±14.3) years and an interval from injury to surgery of (7.9±3.7) d. All the patients were treated by minimally invasive reduction which was assisted by our self-designed intelligent robot, and internal fixation with intramedullary nails. The operation duration, intraoperative reduction duration, intraoperative blood loss, and intraoperative fluoroscopy frequency were recorded. The reduction effect was evaluated by calculating the differences between preoperative planning and postoperative CT reconstruction (i.e., the differences in femoral shaft length and in rotation angle). The hip functional recovery was assessed by Harris hip function Scoring.Results:The mean operation time was 200.0 (161.3, 217.5) min, the reduction time (83.0±35.5) min, the intraoperative blood loss (290.0±110.1) mL, and the intraoperative fluoroscopy 18.5 (9.0, 19.3) times. In all patients, the difference in femoral shaft length was (2.4±1.4) mm, and the difference in rotation angle 5.1°±3.0°. All patients were followed up for (8.2±2.0)months. All the fractures got united at the last follow-up. Their Harris hip function score was (83.3±4.1) points.Conclusion:Our self-designed intelligent robot-assisted reduction system is feasible and effective in the surgery of fresh subtrochanteric fracture of the femur, because the robot system can complete the autonomous planning of reduction approaches before surgery and assist fracture reduction under real-time monitoring with three-dimensional images, leading to fine outcomes.

Objective To study the relationship between the expression of cytochrome c ( Cyt c) and programmed cell death 4 (PDCD4) in pancreatic cancer, and investigate the pathway of PDCD4 inducing the apoptosis of pancreatic cancer cells. Methods Pancreatic cancer specimens from 69 patients who received pancreatic resection from 1990 to 2002 in First Affiliated Hospital of China Medical University were collected. The expression of Cyt c in the 69 paraffin specimens of pancreatic cancer was detected by immunohistochemistry, and the expression of Cyt c in 8 samples of cold-preserved fresh pancreatic cancer and normal pancreatic tissues were detected by Western blot. The expression of PDCD4 and Cyt c in pancreatic cancer was analyzed by paired t test and chi-square test. Results Compared with normal pancreatic tissues, the expression of Cyt c in pancreatic cancer was significantly decreased. The positive expression rate of Cyt c in 69 samples of pancreatic cancer was 41% (28/69). The expression of Cyt c was positive in most patients with positive expression of PDCD4, and the expression of PDCD4 was negative in most patients with negative expression of Cyt c. The expression of PDCD4 and Cyt c was closely correlated with each other (χ2= 10.52, P < 0.05). Conclusions There is a close relationship between the expression of PDCD4 and Cyt c in pancreatic cancer. PDCD4 may induce the apoptosis of pancreatic cancer cells through mitochondrial pathway.