• Clinical and Experimental Reproductive Medicine
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• v.43 no.3
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• pp.181-184
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• 2016

The aim was to report a healthy live birth using re-vitrified-warmed cleavage-stage embryos derived from supernumerary warmed embryos after frozen embryo transfer (ET) in a patient with recurrent implantation failure (RIF). The case was a 39-year-old female with a history of polycystic ovarian syndrome and adenomyosis, along with RIF. After ovarian hyperstimulation, 33 cumulus-oocyte complexes were retrieved and fertilized with conventional in vitro fertilization and intracytoplasmic sperm injection. Because of the risk of ovarian hyperstimulation syndrome, 16 grade B and C embryos were vitrified. After 3 and 6 months, 3 and 4 B-C warmed embryos were transferred to the uterus, respectively. However, implantation did not take place. Ten months later, four embryos were warmed, two grade B 8-cell embryos were transferred, and two embryos were re-vitrified. One year later, the two re-vitrified cleavage-stage embryos were warmed, which resulted in a successful live birth. This finding showed that following first warming, it is feasible to refreeze supernumerary warmed embryos for subsequent ET in patients with a history of RIF.

• BMB Reports
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• v.50 no.9
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• pp.478-483
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• 2017

Budding yeast has dozens of prions, which are mutually dependent on each other for the de novo prion formation. In addition to the interactions among prions, transmissions of prions are strictly dependent on two chaperone systems: the Hsp104 and the Hsp70/Hsp40 (J-protein) systems, both of which cooperatively remodel the prion aggregates to ensure the multiplication of prion entities. Since it has been postulated that prions and the remodeling factors constitute complex networks in cells, a quantitative approach to describe the interactions in live cells would be required. Here, the researchers applied dual-color fluorescence cross-correlation spectroscopy to investigate the molecular network of interaction in single live cells. The findings demonstrate that yeast prions and remodeling factors constitute a network through heterogeneous protein-protein interactions.

• Pediatric Infection and Vaccine
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• v.15 no.2
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• pp.108-114
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• 2008

Japanese encephalitis is the leading cause of viral encephalitis in Asia, where it accounts for up to 50,000 cases. Approximately 20% of affected patients die, and 30-50% of survivors have significant neurological sequelae. Inactivated mouse-brain derived Japanese encephalitis vaccines has been effectively implemented to control the disease effectively in Korea and several other Asian countries. However, the vaccine is expensive and difficult to produce, requires multiple doses, and has been associated with hypersensitivity reactions and rare adverse neurologicale events. The live-attenuated SA14-14-2 vaccine derived from primary hamster kidney (PHK) cells was developed in China and has been used there since 1988. Outside China, it has been licensed and used in Korea and several other Asian countries. This vaccine is effective and inexpensive. However, the lack of precedence for using a PHK cell substrate in a live-attenuated vaccine is a special issue of concern. The WHO working group has recommended additional safety studies in selected high-risk groups, as well as ongoing post-marketing studies to ensure long-term safety. Recently, a new inactivated vaccine and live-attenuated chimeric vaccine have been developed from vero cells. With this background, this article summarized the current status of Japanese encephalitis vaccination worldwide and in Korea.

• Parasites, Hosts and Diseases
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• v.52 no.6
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• pp.595-603
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• 2014

Trichomonas vaginalis secretes a number of proteases which are suspected to be the cause of pathogenesis; however, little is understood how they manipulate host cells. The mammalian target of rapamycin (mTOR) regulates cell growth, cell proliferation, cell motility, cell survival, protein synthesis, and transcription. We detected various types of metalloproteinases including GP63 protein from T. vaginalis trophozoites, and T. vaginalis GP63 metalloproteinase was confirmed by sequencing and western blot. When SiHa cells were stimulated with live T. vaginalis, T. vaginalis excretory-secretory products (ESP) or T. vaginalis lysate, live T. vaginalis and T. vaginalis ESP induced the mTOR cleavage in both time-and parasite load-dependent manner, but T. vaginalis lysate did not. Pretreatment of T. vaginalis with a metalloproteinase inhibitor, 1,10-phenanthroline, completely disappeared the mTOR cleavage in SiHa cells. Collectively, T. vaginalis metallopeptidase induces host cell mTOR cleavage, which may be related to survival of the parasite.

• Journal of Embryo Transfer
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• v.6 no.2
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• pp.47-51
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• 1991

This study investigated full-term development potential of ultrarap idly frozen and thawed mouse 2-cell embryos. Mouse 2-cell embryos, dehydrated by exposure to freezing medium, were directly immersed into liquid nitrogen and thawed in 37$^{\circ}C$ water. The embryos that were frozen and thawed were cultured in uitro and transferred to foster mothers to examine there developmental potential. As a result, the frozen-thawed 2-cell embryos developed to blastocysts in vitro as a similar rate as control 2-cell embryos did(in vitro 2-cell, 86.4%; in vivo 2-cell, 90.9%; solution control, 89.9%; control, 89.7%). Normal live young were obtained from transfer of frozen-thawed embryos to the oviduct and uterus of pseudopregnant recipients (3l.4~56.7%).

• Proceedings of the Korean Society for Agricultural Machinery Conference
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• 2017.04a
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• pp.107-107
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• 2017

3D bioprinting is a technology to produce complex tissue constructs through printing living cells with hydrogel in a layer-by-layer process. To produce more stable 3D cell-laden structures, various materials have been developed such as alginate, fibrin and gelatin. However, most of these hydrogels are chemically bound using crosslinkers which can cause some problems in cytotoxicity and cell viability. On the other hand, thermosensitive hydrogels are physically cross-linked by non-covalent interaction without crosslinker, facilitating stable cytotoxicity and cell viability. The examples of currently reported thermosensitive hydrogels are poly(ethylene glycol)/poly(propylene glycol)/poly(ethylene glycol) (PEG-PPG-PEG) and poly(ethylene glycol)/poly(lactic acid-co-glycolic acid) (PEG/PLGA). Chitosan, which have been widely used in tissue engineering due to its biocompatibility and osteoconductivity, can be used as thermosensitive hydrogels. However, despite the many advantages, chitosan hydrogel has not yet been used as a bioink. The purpose of this study was to develop a bioink by chitosan hydrogel for 3D bioprinting and to evaluate the suitability and potential ability of the developed chitosan hydrogel as a bioink. To prepare the chitosan hydrogel solution, ${\beta}-glycerolphosphate$ solution was added to the chitosan solution at the final pH ranged from 6.9 to 7.1. Gelation time decreased exponentially with increasing temperature. Scanning electron microscopy (SEM) image showed that chitosan hydrogel had irregular porous structure. From the water soluble tetrazolium salt (WST) and live and dead assay data, it was proven that there was no significant cytotoxicity and that cells were well dispersed. The chitosan hydrogel was well printed under temperature-controlled condition, and cells were well laden inside gel. The cytotoxicity of laden cells was evaluated by live and dead assay. In conclusion, chitosan bioink can be a candidate for 3D bioprinting.

• Composites Research
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• v.35 no.3
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• pp.153-160
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• 2022

Cellulose nanofibrils (CNF) based on wood pulp fibers are gained much attention as part of biocompatible hydrogels for biomedical applications such as tissue engineering scaffolds, biomedicine, and drug carrier. However, CNF hydrogels have relatively poor mechanical properties, impeding their applications requiring high mechanical integrity. In this work, we prepare 2,2,6,6-tetramethylipiperidin-oxyl (TEMPO) oxidated cellulose nanofibrils hydrogels mediated with metal cations, which form the metal-carboxylate coordination bonds for enhanced mechanical strength and toughness. We conduct the large amplitude oscillatory shear (LAOS) test and Live/dead cell assay for obtaining nonlinear viscoelastic parameters and cell viability, respectively. In particular, the cell proliferation and viability change depending on the type of metal salt, which also affected the rheological properties of the hydrogels.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.526-526
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• 2013

Plasma technology isbeing developed for a range of medical applications including wound healing. However, the effect of plasma on many cells and tissues is unclear. Cell migration and cell proliferation are very important biological processes which are affected by plasma exposure and might be a potential target for plasma therapy during wound healing treatment. In this study, we confirmed the plasma exposure time and incubation time after plasma treatment in skin fibroblast (L-929 cells) to evaluate the optimal conditions forplasma exposure to the cell in-vitro. In addition, we used a scratch method to generate artificial wound for evaluating the cell migration by plasma treatment. Where, the cells were treated with plasma and migration rate was observed by live-cell imaging device. To find the cell proliferation, cell viability assay was executed. The results of this study indicate the increased cell proliferation and migration on mild plasma treatment. The mechanisms for cell migration and cell proliferation after plasma treatment for future studies will be discussed.

• Asian-Australasian Journal of Animal Sciences
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• v.16 no.4
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• pp.541-548
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• 2003

The Immunoglobulin $IgG_1$ and $IgG_2$ isotype immune responses of domestic ruminants and mice to Cowdria. ruminantium live infection or by immunization with inactivated organisms were determined by the enzyme linked immunosorbent assay and Western blotting. Immunization of goats with inactivated elementary bodies (IEBs) led to a predominant $IgG_1$ isotype response. This indicated that a Th2 response was induced. After challenge, the IgG isotype responses were mixed whereby both $IgG_1$ and $IgG_2$ antibodies were detected. Two goats that survived virulent challenge had a predominant $IgG_2$ isotype response. In cattle live infection by natur l challenge or experiment led to a predominant $IgG_1$ isotype response. Immunization of cattle with IEBs however led to mixed IgG responses characterized by similar $IgG_1$ and $IgG_2$ ratios. In the mouse live infection led to a predominant $IgG_2$ isotype response. This indicated the mouse developed a true Th1 type cell mediated immune response when inoculated with live organisms. Immunization with inactivated organisms on the other hand led to a dominant $IgG_1$ response. It is evident from this work that the immune responses of ruminants and mice to C. ruminantium are different and that using mice as the experimental model for immune responses to Cowdria ruminantium. is not the appropriate.

• International Journal of Stem Cells
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• v.16 no.1
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• pp.117-122
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• 2023

Background and Objectives: mRNA-based protein expression technology has been used to express functional proteins. We have previously generated dopamine neurons from rat-embryo derived neural precursor cells (NPCs) through repeated transfection of synthetic transcription factor mRNA encoding dopamine-inducible genes. However, NPCs began to die approximately 10 d post-transfection. In this study, we examined a long-term transfection protocol that did not affect cell viability. Methods and Results: Experiments were performed in eight groups sorted according to the start date of mRNA transfection. mRNA was transfected into NPCs daily for 21 d and live cell images of each group were recorded. NPCs which were differentiated for more than five days showed sustained gene expression and appreciable viability despite daily mRNA transfection for 21 d. Conclusions: Repeated mRNA transfection requires cells with a sufficient differentiation period.