OBJECTIVE:To probe into the incidence,latency,clinical features and prevention of the antibiotic-associated diarrhea (AAD). METHODS:968 patients with chronic obstructive pulmonary diseases (COPD) treated with antibiotics in the respiratory department of our hospital were prospectively followed for 30 days immediately after administration of antibiotics. RESULTS:The incidence of AAD was 8.47% (82/968) and the latency of AAD was (8.35?5.19) days. 84.15%(69/82)of the AAD cases manifested as simple diarrhea. The AAD was chiefly induced by cephalosporins (42.68%) and penicillins (23.17%). The incidence of AAD increased markedly if the length of the antibiotic treatment was ≥7 days or if at least 3 kinds of the antibiotics were used concomitantly. After discontinuation or alteration of the antibiotics or administration of microbial ecological agents,metronidazole or vancomycin,71(86.59%) of the total 82 AAD cases were cured,10(12.20%) improved and 1 (1.21%) showed no response. CONCLUSION:AAD is a frequent complication of antibiotic therapy. A powerful measure to prevent AAD is rational use of antibiotics.

Objective:To explore the difference in the complexity of different treatment planning systems, multi-leaf collimator (MLC) types and treatment sites of volume-modulated arc therapy (VMAT), and propose a complexity score for plan quality control.Methods:Statistical analysis of 12 complexity metrics including Monaco and Eclipse, Agility, Millennium and High-definition MLC, nasopharyngeal, lung and cervical cancer was performed. Spearman correlation coefficient between complexity metrics was calculated. Principal component analysis was conducted to reduce the dimensionality of the original data set to the first two principal components and explain its physical meaning. Complexity score based on the principal components was calculated to establish warning and action thresholds for plan quality control. The correlation between complexity metrics and γ pass rate was analyzed.Results:Except cervical cancer aperture sub-regions metric, other metrics had significant differences between Monaco and Eclipse. Monaco MLC had a more regular field but higher MU, smaller leaf gap, and longer leaf travel distance. High-definition MLC with smaller leaf width significantly added MLC aperture-related metrics. The first two principal components explained over 80% of the total variance of the original dataset, complexity score was weighted average of first two principal components. The distribution of complexity score for different equipment and sites was different. The warning threshold was expressed as the average plus standard deviation, and the action threshold was expressed as the average plus 2 standard deviations. Complexity metrics and complexity scores had small correlation with γ pass rate, showing weak or irrelevant but statistically significant. Conclusions:Different planning systems, MLC types, and treatment site complexity metrics are significantly different. The complexity score is a useful tool for plan quality control.

Objective:To evaluate the multi-leaf collimator (MLC) performance of TrueBeam accelerator using trajectory log files.Methods:All tests were performed 5 times under different gantry-collimator angle combination. The 1 mm picket fences were constructed by static or dynamic MLC. The control ability for small-field accuracy of accelerator was evaluated. Repeatability was assessed by MLC repeat motion. The movement performance of difference velocities along one direction and the opposite direction were evaluated via a 1 cm picket fences which slipped from -7 cm to 7 cm with a uniform velocity and stopped or immediately back at 7 cm. The MLC performance in a complex program was evaluated by a cross movement test.Results:Both the static and the dynamic picket fences yielded high accuracy. The deviation spectrums of MLC in different gantry angle were consistent, however, an absolute difference of 0.001 1 mm was found. For uniform velocity movement tests with 0°gantry, the RMSE of MLC was increased from 0.015 0 mm to 0.059 8 mm when the speed was accelerated from 5 mm/s to 25 mm/s. Similar results were obtained in non-zero gantry angle. The "overspeed" effect caused by the direction change movement of MLC was less obvious than that caused by speed changed from zero to a uniform velocity movement state. There was no significant change in speed before and after the MLC crossing. The MLC speed fluctuated around the set value, which was independent of the gantry angle.Conclusion:A method for evaluating the performance of MLC using trajectory log files is established, which can evaluate the MLC performance of TrueBeam accelerator and be used for MLC rapid quality control in clinical practice.

BACKGROUND:Inherited heart disease has a high prevalence and mortality rate,but its pathogenesis has not yet been clarified.Although relevant animal models have been established to provide a foundation for the pathogenesis research of inherited heart disease,the value of these research results has been significantly reduced due to differences among species.Therefore,a new model is needed to explore its occurrence and development. OBJECTIVE:To review the current role of induced pluripotent stem cells in disease modeling and potential application prospects in various inherited heart diseases. METHODS:The first author searched the relevant articles published nearly 13 years in PubMed from January to March 2023.The search terms were"induced pluripotent stem cell,inherited heart disease,congenital heart disease".Finally,76 articles were included for analysis. RESULTS AND CONCLUSION:Since 2007,when induced pluripotent stem cells were induced from human somatic cells,many studies have been reported on disease-specific induced pluripotent stem cells.Due to the ability of disease-specific induced pluripotent stem cells to reproduce disease phenotypes,they are expected to become a new research tool for in vitro disease modeling,used to analyze pathogenesis and develop auxiliary drugs.In the research of cardiovascular genetic diseases,cardiomyocytes derived from patient-specific induced pluripotent stem cells contain gene mutations that are involved in cardiac dysplasia.Therefore,it can be used as a new tool to study the potential mechanisms of inherited heart disease.Up to now,induced pluripotent stem cells-derived cardiomyocytes have been widely used to study the molecular mechanisms of various genetic heart diseases,such as cardiac electrophysiological diseases,cardiomyopathy,and some syndromic inherited heart diseases.