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@#Objective To compare and analyze the occupational exposure limit（OEL）of hexavalent chromium compounds in China and foreign countries. Methods The OEL and background information of hexavalent chromium compounds released by nine official and unofficial organizations in seven countries/regions were collected and sorted. The classification，limit levels， formulation principles and compound characteristics labeling of OEL were compared. Results The OEL values published by nine organizations ranged from 0.000 02 to 0.050 00 mg/m3 . Among them，the limits of seven organizations（including China） did not clearly distinguish the soluble types of hexavalent chromium compounds；the limits of eight organizations（including China）were calculated in terms of chromium；seven organizations（including China）have only developed OEL for long-term exposure. The OEL of hexavalent chromium in China was 0.050 00 mg/m3 which is relatively loose. Its carcinogenicity label was consistent with international standards，its sensitization label was consistent with some countries，and its percutaneous absorption label had not been included in the characteristic labeling of limit values. Conclusion It is suggested that the OEL of hexavalent chromium in China should be revised timely，and the systemic adverse effects caused by percutaneous absorption of hexavalent chromium compounds should be focused on. At the same time，it is recommended to systematically adjust the management concepts and principles of all carcinogens.
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@#Objective: To explore the difference in the proliferation inhibition of doxorubicin and dual specific oncolytic adenoviruses (Ad-VT, Ad-T, Ad-VP3 and d-Mock) on breast cancer cells and normal mammary cells. Methods: The proliferation inhibition rates of doxorubicin and recombinant adenovirus(Ad-VT, Ad-T, Ad-VP3and Mock) on breast cancer cells were detected through WST-1 experiment, and the effects of two drugs on the inhibitory rates of normal mammary epithelial cells were also detected. Moreover, the apoptosis rates of doxorubicin and oncolytic adenoviruses on breast cancer cells and normal mammary epithelial cells were evaluated by Annexin V flow cytometry, Hoechst and JC-1 staining, and the difference in the apoptosis rates were also compared. Results: All the recombinant adenovirus could effectively suppress the proliferation of breast cancer cells (P<0.05 or P<0.01), the inhibition effects followed the order ofAd-VT>Ad-T>Ad-VP3>Ad-MOCK, and the inhibition effect was positively correlated with time. Doxorubicin could also effectively suppress the proliferation of breast cancer cells (P<0.05 or P<0.01), and the inhibition effect was markedly enhanced with the increases in does and time. However, doxorubicin also showed strong inhibition effect on the normal mammary epithelial cells, and the inhibition rate achieved 80% under 72 h and 5 ug/ml doxorubicin, while that of oncolytic adenovirus Ad-VT on MCF-10A was 20% at 72 h. The apoptosis effects of oncolytic adenoviruses-induced breast cancer cellwere increased with time, and the apoptosis rate efficiency followed the order of Ad-VT>Ad-T>Ad-VP3>Ad-MOCK, but they displayed low ability to induce normal mammary cell apoptosis. The apoptosis effects of doxorubicin-induced breast cancer cell were similar to that of the normal mammary epithelial cell (P <0.05 or P<0.01), which followed the dose of 0.05<0.5<5 μg/ml. Conclusion: Dual specific oncolytic adenoviruses can effectively suppress the proliferation of breast cancer cells, but they have low inhibition on normal mammary cells, which have displayed superior safety and provide a new method for the biotherapy of tumor.
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@# Objective: To investigate the inhibitory effect of recombinant oncolytic adenovirusAd-Apoptin-hTERTp-E1A(ATV) on luciferase-labeled human lung cancer cells (A549-luc) and human lung cancerA549 cells, and to compare the differences in the inhibitory effect on two cell lines. Methods:ATV was used to infectA549-luc cells andA549 cells respectively. WST-1 and crystal violet staining were used to determine the difference in the inhibitory effect of ATV. Hoechst and Annexin V-FITC/PI staining were used to verify the inhibition mode ofATV. Results: WST-1 and crystal violet staining showed thatATV had significant inhibitory effect on bothA549-luc and A549 cells ( P <0.05). ATV showed significant inhibitory effect on both cells at 24, 48 and 72 h ( P <0.05 or P <0.01), and reached the peak at 72 h; ATV at concentrations of 1, 10 and 100 MOI all showed inhibitory effect on both cells, and reached the peak at 100 MOI. Hoechst staining showed that A549-luc cells and A549 cells infected with ATV showed typical nuclear fragmentation and marginal set. The results of Annexin V-FITC/PI Flow cytometry showed that ATV infection resulted in apoptosis of A549-luc and A549 cells, which was in a time-dependent manner and reached the peak at 72 h( P <0.05 or P <0.01). Conclusion: Insertion of luciferase didn’t significantly change the inhibitory effect and inhibitory mode ofATV onA549-luc cells.ATV exerted its in vitro inhibitory effect onA549-luc and A549 cells by inducing cell apoptosis.