Objective:To explore the difference between the growth inhibition effect of arsenic trioxide(As_2O_3)on the human breast cancer MCF-7 and multidrug resistance MCF-7/ADR cell line.Methods:MCF-7 and MCF-7/ADR cell was cultured with 0.5?mol/L～16?mol/L arsenic trioxide in vitro.MTT test was adopted to detect the growth suppression effect of As_2O_3 in the two cell lines.Apoptosis morphology was studied with light microscope and electron microscope.Apoptosis ratio was analysed with flow cytometry.Results:As_2O_3 could inhibit the proliferation of the MCF-7 and MCF-7/ADR cell line,especially that of 2?mol/L～16?mol/L,and the effect was dose-and-time dependent.The IC_(50) at 96h was 3.0?mol/L for MCF-7 and 12.8?mol/L for MCF-7/ADR.Cell morphology and flow cytometry revealed the growth suppression was caused mainly by apoptosis rather than necrosis;however,to obtain the same inhibitory level,MCF-7/ADR cell required higher concentration of As2O3 and longer processing time.Conclusion:As_2O_3 can inhibit the proliferation in MCF-7/ADR cell as well as MCF-7 cell,though MCF-7/ADR cell is tolerant to As_2O_3,but the tolerance is at a low level.

Objective To explore the basic medical mechanism of XinBao pill on electrophysiological characteristics of hyperpolarization-activated cyclic nucleotide-gated channel 4 (HCN4), and illustrate the mechanism of its therapeutical effect on bradycardia.Methods Human HCN4 mRNA was injected into the Xenopus laevis oocytes, after incubated for 2 ~3 days, channel current properties of HCN4 perfused with 40 mg/L XinBao Pill were observed by double electrode voltage clamp technique.Results At-90mV test potential, compared with control group (no XinBao pill), HCN4 channel peak current and tail current in 40 mg/L XinBao pill group had obvious changes, and V1/2 from ( -103.61 ±3.57)mV to ( -106.42 ±5.33)mV in XinBao pill group, from( -81.11 ±4.26)mV to( -86.36 ±7.44)mV in control group.The values of k from (15.15 ±2.23)mV to (17.33 ±3.58) mV in XinBao pill group, from(11.78 ±0.85)mV to(12.39 ±1.51)mV in control group(n=10).At test potential -90 mV, 40 mg/L XinBao pill perfusion fluid decreased the instantaneous current of(0.15 ±0.24)%, the EC50 was (30.8 ±4.8)mg/L (n=8).At test potential-140 mV~-100 mV level, 40 mg/L XinBao pill group increased the channel activation time constant compared with control group[(226.73 ±31.36)ms vs(143.67 ± 21.44)ms;-140 mV,n=10,P<0.05].40 mg/L XinBao pill group increased the channel deactivation time constant compared with control group [(1293.53 ±95.02)ms vs (647.12 ±61.35)ms;-140 mV,n=10,P<0.05].Conclusion The XinBao pill enhances the instantaneous current of HCN4 in a concentration-dependent manner, and extents channel activation and deactivation processes.

ObjectiveTo evaluate the effectiveness of PBL teaching model for medical students in surgery bed side teaching.MethodsThe method of meta-analysis.ResultsFinally,twenty-six documents met the requirement.The resuhs of Meta-analysis showed that,in the aspect of theory improvement for medical students,WMD=6.46,95 ％ CI 为 2.56 ～ 10.36,P＜0.01 ; in the aspect of skill ability improvement,WMD=5.32,95 ％ CI 为 2.47 ～ 8.16,P ＜0.01.ConclusionThe model of PBL teaching could significantly improve the effectiveness in theoretical knowledge and skill ability.

Objective To elucidate the inhibitory effect of 131I-fulvestrant on the growth of human breast cancer cells and the effect on the important organs.Methods MTT assay was used to clarify the difference in killing effects of the 131I-fulvestranton on MCF-7 cells and MDA-MB-231 cells.Breast cancer MCF-7 cell xenografts in nude mice was establishied,and two different administration methods of the 131I-fulvestrant in the MCF-7 cell to nude mice were given respectively.Organs and tumours of nude mice were observed.Results MTT assay demonstrated that 131I-fulvestrant had similar cytotoxicity against MCF-7 cells and MDA-MB-231 cells,and the former was slightly stronger.Transient contact experiments showed that 131I-fulvestrant could play a tumor suppressor effect on MCF-7 cells continually,but MDA-MB-231 cells wasn't.After the injection of 131I-fulvestrant via caudal vein,the radioactivity concentration on tumor site accounted for (4.33 ± 0.28)％ of the total injection,and the volume of the tumor reduced before gradually increasing again.Radioactivity in the blood accounted for (20.76 ± 2.54)％ of the total injection.Qrgans like liver and kidney also showed radioaction distribution.Its distribution was accorded with the distribution of estrogen receptor.Local injection of 131I-fulvestrant got powerful killing effect on the tumor,and the distribution of the radioaction was mainly confined within the tumor.Conclusion 131I-fulvestrant has a good inhibitory effect on MCF-7 breast cancer cells,which is a superposition of radiotherapy and endocrine therapy,and it is controllable on the general condition and important organs of nude mice.

Objective To dectect the expression of CD54 in thyroid tissue of Hashimotos thyroiditis patients,and expression changes of CD54 on thyroid cells interferred by different agents.Methods The thyroid tissues from 41 cases of Hashimotos thyroiditis were collected and 26 normal thyroid tissues served as normal controls.All thyroid tissues were identified by pathological examination.The positive expression rate and area of CD54 were investigated by immunohistochemical method and quantitative analysis of image analysis system in all thyroid tissues.The expression changes of CD54 in the isolated thyroid cells interferred by 100,500,1 000 pg/ml IL-1? or 10 mg/L NaI or 1 000 pg/ml IL-1? and 10 mg/L NaI for 48 h were detected by flow cytometry.Results The positive expression rate of CD54 in Hashimotos thyroiditis tissues was much more than that of control tissues(P

The rapid mutation and widely spread of duck hepatitis A virus (DHAV) lead to the vast economic loss of the duck industry. To prepare and evaluate bivalent inactivated vaccine laboratory products of DHAV, 6 strains were screened from 201 DHAV-1 strains and 38 DHAV-3 strains by using serotype epidemiological analysis in most of the duck factory. Vaccine candidate strains were selected by ELD50 and LD50 tests in the 6 strains. Continuously passaged, the 5th passaged duck embryos bodies grinding fluid was selected as vaccine virus seeds. The virus seeds were treated with formaldehyde and water in oil in water (W/O/W) emulsions, making into three batches of two bivalent inactivated vaccine laboratory products. The safety test, antibody neutralization test, challenged protection and cross immune protection experiment suggested that the vaccines possessed good safety, and neutralizing antibodies were detected at 7th day and the challenged protection rate reached 90% to 100% at the 14th and 21st day. Moreover, immune duration of ducklings lasted more than five weeks. However, cross-immunity protection experiments with DHAV-SH and DHAV-FS only had 20%-30%. The two bivalent inactivated vaccine laboratory products of duck viral hepatitis were effective and reliable, providing a new method as well as a new product for DHAV prevention and control.
Animals ; Antibodies, Neutralizing ; blood ; Ducks ; virology ; Hepatitis Virus, Duck ; Hepatitis, Viral, Animal ; prevention & control ; virology ; Neutralization Tests ; Picornaviridae Infections ; prevention & control ; veterinary ; Poultry Diseases ; prevention & control ; virology ; Vaccines, Inactivated ; immunology ; Viral Hepatitis Vaccines ; immunology

Background Welders in automobile manufacturers are prone to hand/wrist musculoskeletal disorders (MSDs), which seriously affect workers' physical and mental health. Objective To investigate the factors influencing hand/wrist MSDs of welders in an automobile factory and the population attributable risk percentage (PARP). Methods Five branches of an automobile factory were selected by convenient sampling method, and all qualified welders in the selected branches were enrolled as research participants. The Chinese Musculoskeletal Disorders Questionnaire was used to collect information such as general characteristics of welders, presentation of MSDs in the wrists and hands, and selected ergonomic factors. Log-binomial model in the SAS program was used to calculate the prevalence ratio (PR) of each influencing factor and PARP. Results The prevalence rate of MSDs in the hands/wrists of welders in the automobile factory was 44.1% (345/782). The results of multiple analysis showed that female (PR=1.25, 95%CI: 1.10-1.44), being very tired after work (versus not tired, PR=2.22, 95%CI: 1.16-4.25), twisting wrists (PR=1.44, 95%CI: 1.19-1.74), insufficient operating space (PR=1.22, 95%CI: 1.07-1.40), and holding or pinching objects by hands (PR=1.58, 95%CI: 1.18-2.12) increased the risk of reporting hand/wrist MSDs symptoms. The PARP of major occupational risk factors was: holding or pinching objects by hands, 32.46%; twisting wrists, 21.50%; being very tired after work, 15.28%; and insufficient operating space, 8.18%. Conclusion The prevalence of MSDs symptoms in hands/wrists of welders in this automobile factory is high. Gender, holding or pinching objects by hands, twisting wrists, being very tired after work, and insufficient operating space are the factors affecting hand/wrist MSDs, among which holding or pinching objects by hands and twisting wrists are the priority intervention factors.

Objective To investigate the influence of individual factors and labor organization factors on work-related musculoskeletal disorders (WMSDs) in automobile manufacturing workers, and to provide a scientific basis for the prevention and treatment of WMSDs in automobile manufacturing workers. Methods In April 2020, 5564 workers in an automobile factory were selected by cluster sampling method. The prevalence of WMSDs was investigated by using the Musculoskeletal Disorders Questionnaire, and the influence of individual factors and labor organization factors on WMSDs was investigated by using generalized estimation equation. Results The prevalence rate of WMSDs was 79.00% (4396/5564), and the prevalence rate of multisite WMSDs was 67.95% (3781/5564). The analysis of generalized estimation equation showed that doing the same job every day (OR= 1.478, P < 0.05), age ≥40 years (OR=1.416, P< 0.05), personnel shortage (OR= 1.356, P < 0.05), and work length of 6～10 years and 11～15 years (OR= 1.349, P< 0.05) were the main risk factors for WMSDs in automobile manufacturing workers. Shift work and working time > 40 hours per week increased the risk of WMSDs (P< 0.05). Male and adequate rest time were protective factors for WMSDs. The job correlation matrix showed that WMSDs in most parts had a positive correlation. Conclusions The prevalence of multisite WMSDs of workers in automobile manufacturing industry is high, and unreasonable labor organization is the main risk factor of WMSDs. Appropriate work breaks can effectively reduce the risk of WMSDs, and effective intervention measures should be carried out to prevent the occurrence of WMSDs in workers in automobile manufacturing industry. The generalized estimation equation can better analyze the influencing factors of WMSDs.