OBJECTIVE To establish an modified model of osteonecrosis in the rat and observe the clinical, pathological and imaging manifestations dynamically. METHODS Healthy male SD rats were divided into 5 groups randomly, including the control group (N, 8 rats), and radiation groups (a, b, c and d, 6 rats each group). For radiation groups, the left mandible of each rat was irradiated at doses of 7.0 Gy for 5 fractions, other rats were sham irradiated, serving as control groups.7 days after irradiation, the left mandibular molars of all rats were extracted. The radiation groups rats were sacrificed at 7, 14, 21, 28 days after irradiation randomly, the 2 rats in control group were sacrificed respectively. All the rats' mandibles were taken and examined by clinical manifestation and Micro-CT and histology methods. The data was analyzed with SPSS 18.0 software package. RESULTS In clinical observation, ulcers were seen in the irradiated site at the 7th day, after then, alopecia, occlusion disorder, and pus discharged from buccal side were seen. Weight loss rightly after radiation and weight gain were seen at the 14th day. In pathological observation, marrow cavity changed first. Many adipose cell was first seen at the 7th day, and inflammations, necrosis, and fibrosis were found in medulla in the irradiated groups after that. Significant increment of empty lacunae and decrement of osteocytes were observed in all irradiated groups at the 7th day. Necrotic bone of the irradiated mandible was only found at the 28th day. Lack of new bone formation within the socket was seen in the Micro-CT three-dimensional at 28th day, and there are no more changes at the early-stage in this model. CONCLUSION An modified rat model of osteoradionecrosis was successfully established, which can shorten experimental period, and this model early stage and deserved to be further researched. Can be used to observe clinical, pathological and imaging magnification, which play a basic role in the protection in early stage and deserved to be further researched.

Objective To investigate the current status of prevalence, prevention and management of chronic obstructive pulmonary disease(COPD) in rural area in China. Methods A cross-sectional survey of COPD was conducted in Beijing city, Shanghai city, Guangdong province, Liaoning province,Tianjin city, Chongqing province and Shanxi province. A population-based cluster sample was randomly selected from each rural area. In the selected community,all residents at least 40 years old were recruited,and interviewed with a modified standardized questionnaire from the international burden of obstructive lung diseases (BOLD) study. All participants were tested with spirometry. Those with airflow limitation were performed on post-bronchedilator spirometry. The post-bronchedilator a ratio of forced expiratory volume in one second to forced vital capacity (FEV1/FVC) less than 70% was defined as the diagnostic criteria of COPD. Results (1) Data of 9434 participants was valid for analysis, with a valid response rate of 83. 6% ;the prevalence of COPD in rural was 8. 8% (830/9434), 12. 8% in male and 5.4% in female. (2)The percentage of smoking and the exposure to biomass smoke in rural was 43. 0% (4059/9434) and 83. 1% (7835/9434) respectively; cigarettes cessation rate was 17.5% ; only 12. 4% ( 502/4059 ) of smokers had received advice to quit smoking. (3) Among COPD patients, only 30. 0% (249/830) had ever been diagnosed as COPD, bronchitis, emphysema, or asthma, 2. 4% (20/830) had ever received spirometric tests, and 74. 5% were current smokers; only 7.9% (50/634)COPD patients in stage two or over had received regular drug treatment. Conclusion There was high prevalence and poor prevention and management for COPD in rural areas. Therefore, an enforced prevention and management for COPD are urgent.