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        검색결과 7

        1.
        2014.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The aim of this study was to investigate the prevalence of antimicrobial resistance in Escherichia coli isolated from pigs and their farmhouse environment in Korea. A total of 585 E. coli were isolated in this study during 2006 2007: 426 isolates from 492 pigs and 159 isolates from 312 farmhouse environment samples from 16 different pig farms. The most frequently observed resistance in pig fecal samples was antimicrobials such as tetracycline, streptomycin, and ampicillin. However, resistance to cephalosproins, β-lactam / β-lactam inhibitor combination, and colistin was low. We found an inverse relationship between prevalence of resistant E. coli and animal age. Resistance rate and multi-drug resistance (MDR) was greater in young pigs (piglet and nursery) than for those from adult pigs (grower-finish and sow). Resistance of E. coli from farm environment such as floor, Iron partition, and ventilation was similar with those from pig fecal samples. Farm environment contaminated with MDR bacteria might be a possible source of infections to pigs. Thus, to control and reduce the antimicrobial resistance in pigs, we must also pay attention to the environment.
        4,000원
        2.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porcine has been known to have a great impact on the studies of organ transplantation, biomaterial production and specific biomodel development such as transgenic animals. To achieve such therapeutic purposes, establishment of porcine embryonic stem cells (pESCs) will be needed. Especially, in vitro differentiation toward neural cells from pESCs can be a useful tool for the study of early neural development and neurodegenerative disorders. In addition, these cells can also be used in cell replacement therapies and drug development for neuroprotective and/or neurotoxic reagents. Although several studies reported the successful isolation of pES-like cells, it has been a big challenge to determine optimal conditions to generate pESCs without loss of pluripotency for a long time. The present study was performed for generation and characterization of putative pESCs, and differentiation into neurons and astrocytes. In this study, porcine blastocysts were produced by parthenogenetically activated oocytes. The putative pESCs were cultured in pESC growth media supplemented with a growth factor and cytokines (bFGF, LIF and SCF). Subculture of pESCs was conducted by mechanical dissociation using syringe needles after 4-5 days of incubation. As results, six putative pESC lines were maintained over thirty passages. The putative pESCs were compact, round, flat, and single layered, which were similar to human embryonic stem cell morphologically. Six pES-like cells were positive for alkaline phosphatase activity at every three passages. Furthermore, Oct-3/4, Sox-2, Nanog and SSEA-4 were shown to be expressed in those cells. Also, normal karyotypes of pESCs were observed by Giemsa-staining. Differentiation potential into the three germ layers of the putative pESCs was demonstrated by the formation of embryoid bodies (EB). Besides, the study of ESC is very important in aspect of its application to not only the cell-based replacement therapies but also cellular differentiation research. Our results also showed that RA and N2 supplements activated the neural differentiation in pESC5. Neurofilament-l60 were expressed in neural precursor cells. The expression of markers for specific neural lineages, such as Microtubule-associated protein-2 expressed in matured neuron, was also induced from embryonic neural progenitors. In summary, the pESCs were generated from the parthenogenetically activated blastocysts and the typical characteristics of the cells were maintained for the long term culture. Furthermore, it was successful to differentiate the pESCs into various neural lineages through in vitro neurogenesis system. Eventually, pESCs will be excellent biomedicine in incurable and/or zoonotic diseases by regenerating the damaged tissue.
        4,000원