Yongquan Tian

Radiotherapy is the primary treatment for nasopharyngeal carcinoma while radioresistance can hinder efficient treatment. To explore the role of annexin A1 and its potential mechanisms in radioresistance of nasopharyngeal carcinoma, human nasopharyngeal carcinoma cell line CNE2-sh annexin A1 (knockdown of annexin A1) and the control cell line CNE2-pLKO.1 were constituted and CNE2-sh annexin A1 xenograft mouse model was generated. The effect of annexin A1 knockdown on the growth of xenograft tumor after irradiation and radiation-induced DNA damage and repair was analyzed. The results of immunohistochemistry assays and Western blotting showed that the level of annexin A1 was significantly downregulated in the radioresistant nasopharyngeal carcinoma tissues or cell line compared to the radiosensitive nasopharyngeal carcinoma tissues or cell line. Knockdown of annexin A1 significantly promoted CNE2-sh annexin A1 xenograft tumor growth compared to the control groups after irradiation. Moreover, the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assays revealed that knockdown of annexin A1 significantly inhibited apoptosis in vivo compared to the control groups. We assessed the intracellular reactive oxygen species levels and the extent of radiation-induced DNA damage and repair using reactive oxygen species assay, comet assays, and immunohistochemistry assay. The results showed that knockdown of annexin A1 remarkedly reduced the intracellular reactive oxygen species levels, level of DNA double-strand breaks, and the phosphorylation level of H2AX and increased the accumulation of DNA-dependent protein kinase in nasopharyngeal carcinoma cells after irradiation. The findings suggest that knockdown of annexin A1 inhibits DNA damage via decreasing the generation of intracellular reactive oxygen species and the formation of γ-H2AX and promotes DNA repair via increasing DNA-dependent protein kinase activity and therefore improves the radioresistance in nasopharyngeal carcinoma cells. Together, our findings suggest that knockdown of annexin A1 promotes radioresistance in nasopharyngeal carcinoma and provides insights into therapeutic targets for nasopharyngeal carcinoma radiotherapy.

Background: This study is one part of a five-year tobacco-control project in China, which aimed to gain insight into the smoking behavior, knowledge, and attitudes among medical teachers in China. Methods: In May 2010, a cross-sectional survey was conducted among medical teachers of Xiangya Medical School, Central South University, China. Results: A total number of 682 medical teachers completed the surveys. Latent class analysis indicated the sample of smoking patterns was best represented by three latent subgroups of smoking consumption severity levels. Most respondents were informed of smoking related knowledge, but lack of knowledge on smoking cessation. Most of them held a supportive attitude towards their responsibilities among tobacco control, as well as the social significance of smoking. However, both smoking related knowledge and attitude were not correlated with severity of smoking consumption among medical teachers. Conclusion: The smoking prevalence among medical teachers in China remains high. Programs on smoking cessation training are required. Future study should also develop targeted interventions for subgroups of smokers based on smoking consumption. Persistent and effective anti-tobacco efforts are needed to achieve the goals of creating smoke-free campuses and hospitals.

To investigate the prevalence of nosocomial infections, the distribution of nosocomial infection sites, the use of antibiotic and the situation of detected nosocomial infection pathogens in the Inner Mongolia Autonomous Region of China from 2012 to 2014, to grasp the current conditions of regional nosocomial infections in timely, for the development of infection prevention and control measures to provide a basis for effective hospital. A survey of the prevalence of nosocomial infections was conducted in target hospitals using the combination of a bedside survey and medical record review. In total, 101,907 inpatients were surveyed from 2012 to 2014. There were 1,997 cases of nosocomial infections, accounting for an average prevalence of 1.96%. The infection site was mainly the lower respiratory tract. Higher prevalence of nosocomial infections occurred in the comprehensive intensive care unit (ICU), Neurosurgery Department, and Hematology Department. The average rate of antibiotic use was 33.72%, and the average submission rate for bacterial cultures for patients who received therapeutic treatment with antibiotics was 28.26%. The most common pathogens associated with nosocomial infections were Gram-negative (G−) bacteria, and frequently detected bacterial pathogens included Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae, Acinetobacter baumannii, and Staphylococcus aureus. The survey of the prevalence of nosocomial infections helped to identify problems in the control process of nosocomial infections and to develop targeted measures for the prevention and control of these infections accordingly.

Previous neuropathological studies regarding traumatic brain injury have primarily focused on changes in large structures, for example, the clinical prognosis after cerebral contusion, intracerebral hematoma, and epidural and subdural hematoma. In fact, many smaller injuries can also lead to severe neurological disorders. For example, cerebral microbleeds result in the dysfunction of adjacent neurons and the disassociation between cortex and subcortical structures. These tiny changes cannot be adequately visualized on CT or conventional MRI. In contrast, gradient echo sequence-based susceptibility-weighted imaging is very sensitive to blood metabolites and microbleeds, and can be used to evaluate traumatic cerebral microbleeds with high sensitivity and accuracy. Cerebral microbleed can be considered as an important imaging marker for diffuse axonal injury with potential relevance for prognosis. For this reason, based on experimental and clinical studies, this study reviews the role of imaging data showing traumatic cerebral microbleeds in the evaluation of cerebral neuronal injury and neurofunctional loss.