ABSTRACT
In order to study the regularity of shedding virus from infected SPF chickens and the formation of aerosol of H9N2 subtype AIV, SPF chickens were bred in a positive and negative pressure isolator. Aerosol samples were collected by AGI-30 (All Glass Impinger-30) extractor, and simultaneously trachea and cloaca samples were collected by tracheal swabs and cloacal swabs in different periods after challenged with vi- ruses. The above-mentioned samples were detected by HI, Dot-ELISA and RT-PCR methods. The results in- dicated that aerosols were isolated from the 4 days to the 43 days after inoculation. It was proved that H9N2 subtype AIV could copy themselves in respiratory passage and cloaca, and then could formation of aerosols. AIV H9N2 subtype could be isolated from cloacal and tracheal swabs 3 days after inoculation and lasted for 45 days, viruses were detected from all infected SPF chickens on 7 days.
ABSTRACT
Objective To study the effects of 50 Hz magnetic fields on the in vitro proliferation of human osteosareoma cell line MG-63 with different cell densities.Methods Four different magnetic intensities(1 mT, 2 mT,3 roT,4 mT)were used to stimulate the cells,and the experiment was repeated with different cell densities. The method of MTT was employed to evaluate the level of proliferation.Results Fifty Hz magnetic fields signifi- cantly affected the level of proliferation of human osteosareoma cell line MG-63,and the 2 mT intensity exerted the greatest influence on it.The effects of the magnetic field differed with different cell densities.Conclusion The effect of 50 Hz magnetic fields on the in vitro proliferation of human osteosarcoma cell line MG-63 was not only relat- ed to the magnetic intensity,but also the cell density,