Human embryonic stem cells and therapeutic cloning

The remarkable potential of embryonic stem (ES) cells is their ability to develop into many different cell types. ES cells make it possible to treat patients by transplanting specialized healthy cells derived from them to repair damaged and diseased cells or tissues, known as "stem cell therapy". However, the issue of immunocompatibility is one of considerable significance in ES cell transplantation. One approach to overcome transplant rejection of human ES (hES) cells is to derive hES cells from nuclear transfer of the patient's own cells. This concept is known as "therapeutic cloning". In this review, we describe the derivations of ES cells and cloned ES cells by somatic cell nuclear transfer, and their potential applications in transplantation medicine.

Successful surgical correction of anal atresia in a transgenic cloned piglet

Inbred strains of pig become indispensable for a wide range of biological studies. In biomedical science, it is generally accepted that somatic cell nuclear transfer(SCNT)technology with inbreed strain of pig is essential for xenotransplantation. In this study, we observed the anal atresia in a cloned pig which was derived from fetal fibroblast of inbreed miniature pig. A presumptive anal site of the cloned pig was excised and the rectum was sutured to apposed skin for treatment. This cloned piglet seemed to be normal with healthy status after surgery. This report can be useful for the treatment of anal atresia of cloned piglets.

Effect of beta-mercaptoethanol or epidermal growth factor supplementation on in vitro maturation of canine oocytes collected from dogs with different stages of the estrus cycle

Supplementation of beta-mercaptoethanol (beta-ME) in in vitro maturation (IVM) medium was shown to improve embryo development and quality in several species. Epidermal growth factor (EGF) was also shown to improve IVM of human oocyte and embryo development after in vitro fertilization (IVF). The effect of these two compounds were suggested to be mediated through the synthesis of glutathione (GSH) which is known to play an important role in protecting the cell or embryos from oxidative damage. Thus, it is suggested that supplementation of canine IVM medium with beta-ME or EGF may be of benefit due to its positive role in IVM of various mammalian oocytes and embryo development, including cattle, pigs, rodents and humans. This study investigates the effect of ovarian estrus stage on canine oocyte quality and supplementation of medium with beta-ME or EGF on IVM of canine oocytes. As results, a significantly higher percentage of oocytes progressed to metaphase II (MII) stage in 50 or 100 microM of beta-ME supplemented oocytes collected from the follicular stage. The maturation rate to metaphase I (MI) stage was also significantly higher in oocytes collected from follicular stage and cultured with 25 or 100 microM compared to other experimental groups. After IVM culture, oocytes recovered from dogs with the follicular stage and matured in TCM-199 supplemented with 20 ng/ml EGF yielded better oocyte maturation to MII phase compared to other groups. Taken together, supplementation of beta-ME (50 or 100 microM) or EGF (20 ng/ml) improved IVM of canine oocytes to MII stage.

The Past, Present, and Future of Xenotransplantation

No abstract available.

Effects of Protein Source and Energy Substrates on the In Vitro Development of Bovine Embryos in a Two-step Culture System

In this study, we examined the effects of a two-step culture system, which involves the use of different culture media for early cleavage and later stage embryos, on the in vitro development of bovine embryos. We also investigated the effect of glucose, phosphate and citrate on the in vitro early developmental period of bovine embryos in a two-step culture system. Moreover, the supplementation of different protein sources (BSA-V, BSA-FAF and FBS) during IVC did not affect the frequency of blastocyst development. Using two-step culture, embryos were cultured in protein-free media for an initial 5 days. This was then followed by the same culture media or an FBS supplemented media. The developmental rates of blastocysts in the FBS containing group were significantly higher than in the replaced with no serum containing group. Embryos cultured in mSOF supplemented with 1.5 mM glucose plus 1.2 mM phosphate were significantly inhibited. The inhibition of developmental competence by glucose plus phosphate was consistent with the existence of 0.5 mM sodium citrate. This study indicates that a two-step culture system, which applies different conditions for early cleavage embryos, i.e., serum-free media, vs. later stage embryos, with serum containing media, may be effective for in vitro production systems. In addition, the developmental competence of bovine embryos was depressed in the presence of glucose plus phosphate as compared to either alone or the absence of both. Therefore, the avoidance of this negative effect should allow more optimal conditions to be developed for in vitro production.

Seroprevalence of antibodies to Neospora caninum in dogs and raccoon dogs in Korea

Neospora caninum is an important cause of abortion in cattle, and dogs are its only known definitive host. Its seroprevalence among domestic urban and rural dogs and feral raccoon dogs (Nyctereutes procyonoides koreensis) in Korea was studied by indirect fluorescent antibody test (IFAT) and by the neospora agglutination test (NAT), respectively. Antibodies to N. caninum were found in 8.3% of urban dogs and in 21.6% of dogs at dairy farms. Antibody titers ranged from 1: 50 to 1: 400. Antibodies to N. caninum were found in six (23%) of 26 raccoon dogs. However, the potential role of raccoon dogs as a source of horizontal transmission of bovine neosporosis needs further investigation. The results of this study suggest that there is a close relationship between N. caninum infection among dairy farm dogs and cattle in Korea. This study reports for the first time upon the seroprevalence of N. caninum infection in raccoon dogs in Korea.

Effect of IP3 and ryanodine treatments on the development of bovine parthenogenetic and reconstructed embryos

For parthenogenetic activation as a model system of nuclear transfer, microinjection and electroporation as activation treatments in bovine metaphase II oocytes were administered to each of three groups as follows: control group (treatments with Ca2+, Mg2+ -free PBS+100 micro M EGTA), IP3 group (control+25 micro M IP3) and IP3+ ryanodine group (control+25 micro M IP3+10 mM ryanodine). In experiments using microinjection, no significant differences were observed between any of the developmental stages of the electroporation experiment. For electroporation, cleavage rates were significantly higher in the IP3+ryanodine group than in the IP3 or control group (85.6% vs 73.7% or 67.6%, respectively). In the subsequent stages of embryonic development, such as morula and blastocyst formation, the IP3 and ryanodine group exhibited significantly higher rates of morula fomation than the IP3 or control groups (40.6% vs 24.2% or 16.7%, respectively). Similarly, the rate of blastocyst formation in the IP3+ryanodine group was significantly higher than the control group (16.3% vs 6.9%) but did not differ significantly from the IP3 group (16.3% vs 9.5%). In nuclear transfer, activation was performed at 30 hpm by microinjection and elecroporation with 25 micro M IP3+ 10 mM ryanodine followed by 6-DMAP treatment. No significant differences were observed at any stage of embryonic development and none of the embryos activated by electroporation reached either the morula or blastocyst stage. However, 3.8% and 1.9% of embryos activated by microinjection sucessfully developed to the morula and blastocyst stages, respectively. In conclusion, activation treatments using IP3 and ryanodine are able to support the development of bovine parthenogenetic and reconstructed embryos.

The Role of Gonadotropin: Releasing Hormone ( GnRH ) and Its Receptor in the Extrapituitary Tissues / 대한내분비학회지

No abstract available.