The knowledge of occupational health and occupational medicine is the basis for students of preventive medicine in the future work.The paper expatiates on how to make students build up their thought of preventive medicine during the teaching course,and raise their interest in it and cultivate their comprehensive capability.The purpose of the paper is to enhance the teaching result and quality.

Objective To evaluate the distribution of Pneumoconiosis and provide scientific basis for preventing the occur-rence of Pneumoconiosis and improving the life quality of patients for the workers in coal mine of Songzao.Methods Retrospective epidemiological research and chi-square test were used for all collected Pneumoconiosis cases in Songzao coal mine of Chongqing from 2010 to 2012.Results From 2010 to 2012,the incidence was significantly different(χ2 =25.048,P <0.05),and the prevalence was significantly different(χ2 = 11.223,P <0.05).Besides,the mean duration of dust exposure was(20.50± 5.45)years.Mean-while,the difference of proportion between stageⅠand stageⅡ、stage Ⅲ show statistical significance(χ2 =9.162,P <0.05).What′s more,the rate of complicated pulmonary tuberculosis with pneumoconiosis was 2.94%.From 1979 to 2012,the difference in propor-tion of different stage′s fatality was significantly different(χ2 = 174.101,P <0.05).Conclusion Nearly three years,although the incidence and prevalence were all decreasing,but the situation was not optimistic.Pneumoconiosis are mainly in stageⅠ,and the le-thality of Ⅲ period is far stronger than the other two.Prevention of complication should be paid high attention.

Objective To observe changes of the ultrastructure and the cell cycle of hepatoma cells exposed to ultrasound-mediated disruption. Methods Suspensions of Walker-256 hepatoma in vitro exposed to ultrasound disruption with the acoustic power output 0 22 W and the ultrasound frequency 42 kHz were observed by the scanning electron microscopy, the transmission electron microscopy and the flow cytometric analysis of DNA content. Results Cells after ultrasound disruption revealed by scanning electron microscopy exhibited ruptured membrance, disordered organellae and disrupted nucleus, showing typical severe destruction of the cells. Flow cytometric analysis of DNA content demonstrated an increased in the population of cells in the G 2 and M phases of the cell cycle but a decrease in number of cells in the S phase, suggesting an inhibition of the cell synthese and an increased sensitivity to radiation. Conclusions Ultrasound disruption can destroy tumor cells effectively at the cellular level.

To improve the quality of experimental teaching,investigating the independent design experiments are carrying out in preventive medicine by public health experimental teaching center in our school.We take preventive medicine professional as an example,and besides the classical basis experiments,some experiments are verification project at present,in which students are not strongly interested.On the basis of the integration of the classic experiments,according to the national standard of the experimental method,we are trying to carry out part of the independent design experiments to meet the needs of students learning.The effect of those independent design experiments shows that it is appropriate carrying out independent design experiments on the basis of the existing classical experimental project in preventive medicine experimental teaching,to a certain extent,which will stimulate students' learning interest and enhance their sense of achievement.This study is conducive to the cultivation of medical students' innovation,independent thinking,analysis and problem-solving ability,practical ability and teamwork spirit.

Objective To examine the expression of scinderin in primary hepatocellular carcinoma (HCC) and its paired portal vein tumor thrombus (PVTT) tissues; and to explore its role in the development of HCC and its relationship with prognosis of HCC.Methods Immunohistochemistry was used to detect the expressions of scinderin in tumor-adjacent normal liver tissues,HCC tissues and PVTT tissues from 33 patients.Results The positive expression rates of scinderin in tumor-adjacent normal tissues,HCC tissues and PVTT tissues were 69.7％ (23/33),45.5％ (15/33) and 24.2％ (8/33) respectively.A significantly lower scinderin expression was found in HCC tissues when compared with tumor-adjacent normal tissues (P ＜ 0.05).Also,the expression of scinderin in PVTT tissues was significantly lower than in HCC tissues (P ＜ 0.05).The expression of scinderin in HCC tissues significantly correlated with tumor size,absence of tumor capsule and serum AFP (P ＜0.05).The recurrence-free survival (RFS) and overall survival (OS) of Scinderin-positive patients were significantly longer than Scinderin-negative patients (P ＜ 0.05).Multivariate analysis revealed scinderin expression level to be an independent risk factor affecting RFS and OS after curative resection.Conclusions Scinderin was down-regulated in HCC tissues and PVTT tissues when compared with its paired tumor-adjacent normal liver tissues.The expression level of scinderin correlated with HCC recurrence and prognosis.Scinderin can be used as an indicator of prognosis of HCC patients with PVTT.

Objective To investigate the safety and clinical effect of endovascular radiofrequency ablation (RFA) catheter, the HabibTM VesOpen, in treating portal vein tumor thrombus. Methods Fifteen patients of hepatocellular carcinoma associated with portal vein thrombus causing obstruction of blood flow were enrolled in this study. Guided by ultrasound percutaneous portal catheter implantation was performed, then, under DSA guidance RFA catheter was placed at portal vein tumor thrombus. RF generator (RITA) was connected to the electrodes, the power was set at 10 W for 2 - 10 minutes. The technical success rate, the postoperative complications, the hepatic and renal functions as well as routine blood tests, portal vein blood flow and the ablation extent of portal vein tumor thrombus were evaluated, and the results were analyzed. Results The procedure was successfully accomplished in all patients. No technique-related complications, such as hemorrhage, vessel perforation, bile leak complicated by infection, liver abscess, abdominal bleeding occurred. Direct portography performed immediately after RFA showed that the portal vein was re-opened. Laboratory examinations performed 4 weeks after RFA showed that no obvious changes in hepatic functions and routine blood tests were observed. Doppler ultrasound examinations revealed that flowing blood was obviously displayed within previously obstructed portal vein. CT scanning was carried out in some patients with portal vein thrombus, and it indicated that the portal vein tumor thrombus was reduced in size or even disappeared. Conclusion For the treatment of portal vein tumor thrombus in patients with hepatocellular carcinoma, endovascular radiofrequency ablation is technically feasible, and the initial results indicate that this technique is an effective treatment.

Objective To investigate the effect and mechanism of DADS in inhibiting the proliferation and inducing apoptosis of gastro-esophageal cancer cells in vitro.Methods The gastro-esophageal adenocarcinoma cells OE1 9 were treated by DADS of different concentrations in vitro.Morphologic changes were observed by the microscope and MTT assay was performed to test the growth-inhibitory effect of DADS on OE1 9 cells.Apoptosis rate of OE1 9 treated with different concentrations of DADS was measured by flow cytometry.Real-time PCR was used to detect DADS-induced effects on mRNA expressions of Caspase-3 ,Caspase-9 ,Bcl-2 ,Bax and NF-κB in OE1 9 cells.Results DADS inhibited the proliferation of OE19 cells in a dose-dependent manner.The apoptosis rate of OE19 cells was 14.0%,25.4% and 19.0% and 27.2%,respectively,when treated with 40 and 80μg/mL DADS for 24 h and 48 h.Real-time PCR assay showed that DADS could enhance mRNA expression levels of Caspase-3 and Caspase-9 and significantly decrease the mRNA expression levels of NF-κB and Bcl-2 and the ratio of Bcl-2/Bax. Conclusion DADS can significantly inhibit the proliferation and induce the apoptosis of gastro-esophageal adenocarcinoma cells via mitochondria-dependent pathways,which may be related to NF-κB and Bcl-2 families.

The incidence of hepatocellular carcinoma (HCC) with portal vein tumor thrombosis (PVTT) is very high,and the prognosis is often unsatisfactory.Currently,some therapy such as radiotherapy or radiation combined with interventional therapy are effective and worth attention.Radiation therapy was divided into external beam radiation therapy and internal beam radiation therapy according to different administration pathway.This article summarized the current situation and prospect of radiotherapy.

Objective To study on imagination features of tumor thrombi in the portal vein of primary liver cancer (PLC). Methods We established a new type system of tumor thrombi, with Ⅰ 0 to Ⅳ, a total of 5 types and 8 sub-types in the portal vein of PLC based on normal intrahepatic portal vein anatomy and growing features of the tumor thrombi. The relationship between the types and the imaging diagnosis of 130 PLC cases with tumor thrombi in the portal vein was studied. Results 85%(110/130) cases of PLC with tumor thrombi in the portal vein belongs to type Ⅱ or Ⅲ when being first diagnosed in the hospital. The resectability rates for type Ⅰ, Ⅱ, Ⅲ, Ⅳ were 62%(5/8), 16%(10/62), 10%(5/48), 0 (0/12), respectively, and chemoembolization therapy (TACE) was given in 38%(3/8), 40%(25/62), 27%(13/48), 16%(2/12), respectively. Conclusions The new types of tumor thrombi are helpful for diagnosis and treatment of PLC with tumor thrombi in the portal vein.

Objective To study the relationship between gastroesophageal varices and bleeding and portal venous tumor thrombi in patients with hepatocellular carcinoma(HCC). Methods From Jan. 2000 to Jan. 2003, 84 HCC patients with portal vein tumor thrombi were divided into Ⅰ～Ⅳ groups according to Ⅰ～Ⅳ types of tumor thrombi. The grade of gastroesophageal varices, the median survival time and the death cause for group Ⅰ～Ⅳ were retrospectively analyzed. Results Mild grade of gastroesophageal varices accounted for 64.7%, 6.0%, 85.7%,100%, respectively in group Ⅰ(n=17), Ⅱ(n=26),Ⅲ( n=35) and group Ⅳ(n=6),respectively. Severe varices were found in less than 5% in all four groups. The median survival periods were 10.1, 7.2, 5.7 and 3.0 months, respectively (P=0.0001). Most cases died from esophageal and gastric variceal bleeding and hepatic failure, with each accounting for about 50% of the mortality in all the 4 groups. Conclusions Portal venous tumor thrombi of HCC patients was not the major cause leading to esophageal and gastric varices and bleeding.