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        검색결과 9,514

        5109.
        2011.10 구독 인증기관·개인회원 무료
        5111.
        2011.10 구독 인증기관·개인회원 무료
        5116.
        2011.10 구독 인증기관·개인회원 무료
        Pig parthenotes were able to develop in vivo for 30 days with normal morphology. In pig, during blastocyst elongation between day 10 and 12 of gestation, estrogen production and secretion by conceptus increases, serving not only as the signal for maternal recognition of pregnancy, but also as a stimulus for the production of proteins and growth factors within the uterine environment that initiate implantation. Cloning efficiency is still very low regardless of species. To increase the productive efficiency of (transgenic, TG) clones, an advanced somatic cell nuclear transfer (SCNT) method may need. Here we report the productions of transgenic cloned pigs using cloned embryos and parthenotes simultaneously. Fibroblasts were isolated from an ear skin of a 10‐day‐old NIH miniature pig. The ear fibroblast cells were transfected with the alpha1,3‐ Galactosyltransferase knock‐out/human CD46 knock‐in (GalT KO/hCD46 KI). For SCNT, the TG somatic cells were used as donor cells. Immediately after fusion confirmation, the TG cloned embryos and parthenotes were transferred into both oviducts of surrogates. The mean number of TG cloned embryos and parthenotes was 137 (±15.2) and 123(±27.1), respectively. The pregnancy and delivery rate was (55.6%, 10/ 18) (44.4%, 8/18), respectively. Totally 19 GalT KO/hCD46 KI cloned piglets were delivered. Among them, 11 piglets were survived and 8 piglets were born stillbirth. The healthy 5 piglets are still survived.
        5117.
        2011.10 구독 인증기관·개인회원 무료
        Urokinas type plasminogen activator (uPA) has been used as a therapeutic agent for treating human diseases such as thrombosis. Attempts to transgenically overexpress the uPA in animal bioreactors have been hampered due to side effects associated with this functional protein hormone on homeostasis. Recently, chicken has been emerged as a potential candidate for use as bioreactor to produce proteins of pharmaceutical importance. Since this species has low homology uPA sequence with mammals, we hypothesized that chicken could be used as a potential bioreactor for production of human uPA. In this study, using replication‐defective Murine Leukemia Virus (MLV)‐based retrovirus vectors encapsidated with Vesicular Stomatitis Virus G Glycoprotein (VSV‐G), we attempted to make transgenic chicken expressing human uPA (huPA). The recombinant retrovirus was injected beneath the blastoderm of non‐incubated chicken embryos (stage X, at laying). After 21 days of incubation (at hatching), all of the 38 living chicks that assayed, were found to express the vector‐encoded huPA gene in various organs and tissues, which was under the control of the Rous Sarcoma Virus (RSV) or Cytomegalovirus (CMV) promoter. Using specific primer set for huPA, PCR and RTPCR analyses of gDNA isolated from these samples demonstrated these chickens were transgenic for huPA. Furthermore, successful germ line transmission of huPA transgene was confirmed and next generation whole body huPA transgenic chickens were also produced. We also assayed huPA protein titer in blood (17.1 IU/ml) and eggs (4.4 IU/ml) of whole body huPA transgenic chicken. Thus, our results demonstrated that chicken could be used as bioreactors to produce huPA.
        5118.
        2011.10 구독 인증기관·개인회원 무료
        The production of transgenic animals using somatic cell nuclear transfer (SCNT) has been widely described. A critical problem in the production of transgenic animals is the uncontrolled constitutive expression of the foreign gene which occasionally results in serious physiological disorders in the transgenic animal. In this study, we designed three different expression vectors that express the hEPO gene. hEPO is a hormone produced by the kidney that promotes the formation of red blood cells by the bone marrow. For the in vitro production of transgenic embryos, the different expression vectors were transduced into holstein ear fibroblast cells, respectively, and GFP expressed donor cells were transferred into enucleated oocytes, and then the reconstructed SCNT embryos were developed into pre-implantation stage. From three replicates, GFP expressed 112 transgenic SCNT embryos were produced. When their cleavage rate and blastocyst rate were compared with non-transgenic SCNT embryos, the results were presented into 73.2% vs. 76.9% and 26.8% vs. 30.6%, respectively, there were no differences. Also, total cell number and ICM cell numbers of day 8 blastocysts were statistically not different between the transgenic SCNT groups (120.6±7.9 and 31.4±8.2) and control SCNT group (128.3±4.8 and 35.3±4.0). The GFP expression levels were presented consecutively high during the culture of transgenic SCNT embryos. By analysis of semi-quantitative RT-PCR, the relative expression levels of hEPO mRNA and pluripotent gene were determined. These results demonstrated that the hEPO expressed transgenic bovine embryos can be efficiently produced in vitro by SCNT technique, while their potential of cloned animal production have to be examined in further study.
        5119.
        2011.10 구독 인증기관·개인회원 무료
        Despite of the absence of hyperacute rejection and acute humoral xenograft rejection, the organ graft of the a1,3-galactosyltransferase (GalT) gene knockouted (KO) and complement regulatory protein (CRP) expressing pig into a nonhuman primate is rejected by development of a thrombotic microangiopathy and/or a consumptive coagulopathy. Thus further introduction of genes to overcome the coagulation incompatibilities between pig and primate under GalT KO/CRP genetic background has been strongly suggested. CD73 (ecto-5'-nucelotidase) is an enzyme attached via a glycosyl phosphoinositol anchor to the extracellular membrane of endothelial cells, which catalyses the hydrolysis of adenosine triphosphate to adenosine. Loss of activity of CD73 results in activation and aggregation of platelets by a reduced capacity to convert nucleotides to adenosine. In previous study, we reported generation of GalT KO fibroblasts concurrently expressing membrane cofactor protein and produced cloned pigs by nuclear transfer of the fibroblast cells (1). In this study, we constructed a vector for expression of human CD73 under control of promoter of pig Icam2 gene expressed specifically at endothelial cells. This vector was introduced into porcine fibroblasts using the nucleofection technology, by which we had forty three fibroblasts clones carrying pIcam2- CD73 vector. Somatic cell nuclear transfer resulted in generation of two transgenic piglets survived.
        5120.
        2011.10 구독 인증기관·개인회원 무료
        Stem cell therapy is undoubtedly the most promising therapeutic approach for neurological disorders. Adipose tissue is ubiquitous and it can be easily harvested in large quantities under local anesthesia with little patient discomfort, making adipose tissue into the ideal large-scale source for research on clinical applications. In this study we monitored the neuronal cell differentiation potential of human adipocyte in the following condition; i) N2 medium containing 200 uM ascorbic acid (AA) and/or 10 uM flavonoid (F) and ⅱ) N2 medium containing AA and/or 10 ng/ml brain derived neurotrophic factor (BDNF) and/or, 200 ng/ml sonic hedgehog (SHH) plus 100 ng/ml fibroblast growth factor (FGF) 8. Adipose stem cells were cultured in above described differentiation condition for three weeks. RT-PCR analysis demonstrated that the mRNA levels of neuronal cell markers in differentiated adipose stem cells. Under the culture condition using N2 medium containing AA, the expression level of nestin (neural progenitor marker) m- RNA was high in all groups, while those of Neuro D, and LEP and FABP4 (adipocyte marker) mRNA were significantly decreased. Also, the addition of BDNF or SHH+FGF8 in N2 medium containing AA enhanced the neural cell differentiation from adipose stem cells, the expression level of Map2 (mature neuron) mRNA was increased, and that of TH (dopaminergic neuron marker) mRNA was high. In addition, we confirmed that the flavonoid addition has effect on the increase of Map2 expression. These results demonstrate that our designed culture condition has effect on the neural cell differentiation of adipose stem cells and this stimulatory effect may be further enhanced by transplantation.