• Journal of Korean Neurosurgical Society
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• 제61권6호
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• pp.680-688
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• 2018

Objective : To mitigate the risk of iatrogenic instability, new posterior decompression techniques able to preserve musculoskeletal structures have been introduced but never extensively investigated from a biomechanical point of view. This study was aimed to investigate the impact on spinal flexibility caused by a unilateral laminotomy for bilateral decompression, in comparison to the intact condition and a laminectomy with preservation of a bony bridge at the vertebral arch. Secondary aims were to investigate the biomechanical effects of two-level decompression and the quantification of the restoration of stability after posterior fixation. Methods : A universal spine tester was used to measure the flexibility of six L2-L5 human spine specimens in intact conditions and after decompression and fixation surgeries. An incremental damage protocol was applied : 1) unilateral laminotomy for bilateral decompression at L3-L4; 2) on three specimens, the unilateral laminotomy was extended to L4-L5; 3) laminectomy with preservation of a bony bridge at the vertebral arch (at L3-L4 in the first three specimens and at L4-L5 in the rest); and 4) pedicle screw fixation at the involved levels. Results : Unilateral laminotomy for bilateral decompression had a minor influence on the lumbar flexibility. In flexion-extension, the median range of motion increased by 8%. The bone-preserving laminectomy did not cause major changes in spinal flexibility. Two-level decompression approximately induced a twofold destabilization compared to the single-level treatment, with greater effect on the lower level. Posterior fixation reduced the flexibility to values lower than in the intact conditions in all cases. Conclusion : In vitro testing of human lumbar specimens revealed that unilateral laminotomy for bilateral decompression and bone-preserving laminectomy induced a minor destabilization at the operated level. In absence of other pathological factors (e.g., clinical instability, spondylolisthesis), both techniques appear to be safe from a biomechanical point of view.

• 생명과학회지
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• 제33권8호
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• pp.612-622
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• 2023

생체 면역조직에서는 면역세포의 성장, 분화에 있어서 매우 중요한 역할을 수행하는 면역조직 기질세포가 존재하며, 이들은 서로 연결된 3차원적인 그물구조를 형성하면서 그 사이의 공간에 위치한 면역세포와의 상호작용을 통해 다양한 면역반응을 수행한다. 따라서 생체환경을 모사한 면역세포의 배양이 이루어지기 위해서는 면역세포들이 상호작용할 수 있는 3차원적 면역조직 기질세포 뼈대의 구축이 매우 중요한 의의를 지닌다. 특히 면역반응에서 핵심적인 기능을 수행하는 T세포의 생존, 성장 및 분화에 있어서 필수적인 역할을 하는 흉선상피세포에 대한 3차원적 배양은 T세포의 연구에 필수적으로 요구되지만, 아직 이에 관한 연구가 거의 이루어지지 않은 실정이다. 본 연구에서 흉선상피세포는 폴리도파민으로 코팅된 PCL 및 PCL/PLGA 지지체에서 비코팅군에 비해 부착 및 성장이 촉진되었다. 또한 폴리도파민으로 코팅된 지지체에서 흉선상피세포를 배양하였을 때 2차원 배양군에 비해 흉선세포형성촉진인자의 유전자 발현이 더 증가하였다. 따라서 본 연구는 면역조직 기질세포의 3차원 배양 기술의 개발에 크게 기여할 수 있을 것으로 사료된다.

• Clinical and Experimental Reproductive Medicine
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• 제43권1호
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• pp.38-43
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• 2016

Objective: The number of assisted reproductive technology (ART) clinics, ART cycles, clinical pregnancy rate (CPR), and number of newborns conceived using ART have steadily increased in South Korea. This aim of this study was to describe the status of ART in South Korea between January 1 and December 31, 2011. Methods: A localized online survey was created and sent to all available ART centers via email in 2015. Fresh embryo transfer (FET) cases were categorized depending on whether standard in vitro fertilization, intracytoplasmic sperm injection (ICSI), or half-ICSI procedures were used. Thawed embryo transfer (TET) and other related procedures were surveyed. Results: Data from 36,990 ART procedures were provided by 74 clinics. Of the 30,410 cycles in which oocytes were retrieved, a complete transfer was performed in 91.0% (n=27,683). In addition, 9,197 cycles were confirmed to be clinical pregnancies in the FET cycles, representing a pregnancy rate of 30.2% per oocyte pick-up and 33.2% per ET. The most common number of embryos transferred in the FET procedures was three (38.1%), followed by two (34.7%) and one (14.3%). Of the 8,826 TET cycles, 3,137 clinical pregnancies (31.1%) were confirmed by ultrasonography. Conclusion: While the overall clinical pregnancy rate for the TET cycles performed was lower than the rate reported in 2010 (31.1% vs. 35.4%), the overall CPR for the FET cycles was higher than in 2010 (33.2% in 2011 and 32.9% in 2010). The most common number of embryos transferred in FET cycles was three, as was the case in 2010.

• Clinical and Experimental Reproductive Medicine
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• 제44권1호
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• pp.47-51
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• 2017

Objective: This study was designed to report the status of assisted reproductive technology (ART) therapy in South Korea between January 1, 2012 and December 31, 2012. Methods: A localized online survey, originally developed by the International Committee Monitoring Assisted Reproductive Technologies, was first launched and provided to all available ART centers via email in 2015. Fresh embryo transfer (FET) cases were categorized as standard in vitro fertilization, intracytoplasmic sperm injection (ICSI), or half-ICSI. Thawed embryo transfer (TET) and other related procedures, including surgical sperm retrieval, were surveyed. Results: Data from 33,956 ovum pick-up procedures were provided by 75 clinics in 2012. Of the 33,088 cycles in which ovums were retrieved, a complete transfer was performed in 90.5% (29,932 cycles). In addition, 10,079 FET cycles were confirmed to have resulted in clinical pregnancy, representing a pregnancy rate of 30.5% per ovum pick-up and 33.7% per ET. The most common number of embryos transferred in FET was 2 (41.6%), followed by 3 (34.0%), and non-elective single ETs (10.0%). Of the 10,404 TET cycles in which transfer was completed, 3,760 clinical pregnancies (36.1%) were confirmed by ultrasonography. Conclusion: The overall clinical pregnancy rate for FET and TET cycles in 2012 was higher than in 2011 (33.7% vs. 33.2% and 36.1% vs. 31.1%, respectively). The most common number of embryos transferred in FET cycles was 2, unlike in 2011.

• 한국수정란이식학회지
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• 제12권1호
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• pp.37-48
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• 1997

I. The Factors Influencing In Vivo Embryo Production by Condition of Superovulation Treatment These studies were carried out to establish an effective and practical system for comrnercialization of embryo production techniques by analyzing several factors influencing in vivo embryo production on superovulation treatment in Korean native cattle. In vivo embryos were flushed 226 times from 128 donors.The results obtained from the studies on the factors influencing in vivo embryo production by superovulation treatment were as follows : FSH-P had a significiant advantage(83.0%) over SUPER-OV in the percentage of fertilized embryos(P<0.01). No difference was found loetween FSH-P and SUPER-OV in the percentage of transferable and freezable embryos.2. The response of superovulation by SUPER-OV was greater than that of FSH-P The donors having 8~9 and more than 10 of corpora lutea(CL) derived by FSH-P were 40.0%(most frequent) and 33%, respectively. The donors having more than 12 and 10 CL derived by SUPER -OV were 33.3% (most frequent) and 56.6%, respectively.3. Embryo production after treatment of repeated superovulation was remarkablely decreased at 3rd time by FSH-P but did not differ among 1, 2 and 3rd times by SUPER-OV. Embryo production on intervals of repeated superovulation was significantly different for the number and percentage of fertilized, transferable and free-zable' embryos in FSH-P (P<0.01) and rernarkablely decreased in repeated superovulation of 81~120 interval days. The SUPER-OV showed no differences in interval days of repeated superovulation and was found better than FSH-P in the response of repeated superovulation. (Key words : in Vivo embryo, superovulation, FSH -P, SUPER-OV)

• 한국수정란이식학회:학술대회논문집
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• 한국수정란이식학회 2002년도 국제심포지엄
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• pp.73-73
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• 2002

Nuclear transfer (NT) techniques have advanced in the last years, and cloned animals have been produced by using somatic cells in several species including pig. However, it is difficult that the nuclear transfer porcine embryos development to blastocyst stage overcoming the cell block in vitro. Abnormal segregation of chromosomes in nuclear transferred embryos on genome activation stage bring about embryo degeneration, abnormal blastocyst, delayed and low embryo development. Thus, we are evaluated that the correlations of the frequency of embryo developmental rates and chromosome aberration in NT and In viかo fertilization (IVF) derived embryo. We are used for ear-skin-fibroblast cell in NT. If only karyotyping of embryonic cells are chromosomally abnormal, they may difficultly remain undetected. Then, we evaluate the chromosome aberrations, fluorescent in situ hybridization (FISH) with porcine chromosome 1 submetacentric specific DNA probe were excuted. In normal diploid cell nucleus, two hybridization signal was detected. In contrast, abnormal cell figured one or three over signals. The developmental rates of NT and IVF embryos were 55% vs 63%, 32% vs 33% and 13% vs 17% in 2 cell, 8 cell and blastocyst, respectively. When looking at the types of chromosome aberration, the detection of aneuploidy at Day 3 on the embryo culture. The percentage of chromosome aneuploidy of NT and IVF at 4-cell stage 40.0%, 31.3%, respectively. This result indicate that chromosomal abnormalities are associated with low developmental rate in porcine NT embryo. It is also suggest that abnormal porcine embryos produced by NT associated with lower implantation rate, increase abortion rate and production of abnormal fetuses.

• Asian-Australasian Journal of Animal Sciences
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• 제17권5호
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• pp.588-593
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• 2004

The gene expression of porcine adiponectin and stearoyl coenzyme A desaturase (SCD) was investigated in this study. The partial gene sequences for adiponectin and SCD were amplified by RT-PCR from subcutaneous adipose tissue and cloned by TA cloning techniques. Sequences of these genes were determined and found to be highly homologous to that of other species, suggesting similar function of these genes as in other species. The transcripts of these adipocyte-related genes in pig tissues were measured by Northern analysis. The transcripts for adiponectin and SCD were highly expressed in porcine subcutaneous adipose tissue; the transcripts for SCD were also barely detected in the liver, but the greatest concentrations were in the adipose tissue. In porcine stromalvascular cells (S/V cells) cultured in vitro, transcripts for adiponectin and SCD increased gradually during adipocyte differentiation. The level of adipocyte adiponectin mRNA was associated with late adipocyte differentiation, indicating the gene may not be involved in adipocyte differentiation but has great importance in porcine adipocyte functions. The SCD transcripts were not detectable until 2 d after induction of adipocyte differentiation. It was highly expressed in differentiating porcine adipocytes (2 to 10 d after the induction of adipocyte differentiation), indicating a significant role of SCD in adipocytes.

• Journal of Periodontal and Implant Science
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• 제52권5호
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• pp.411-421
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• 2022

Purpose: In this study, we aimed to evaluate the degree of heat generation when a novel drill design with an irrigation slot was used with metal sleeve-free (MF) and metal sleeve-incorporated (MI) surgical guides in an environment similar to that of the actual oral cavity. Methods: A typodont with a missing mandibular right first molar and 21 bovine rib blocks were used. Three-dimensional-printed MF and MI surgical guides, designed for the placement of internal tapered implant fixtures, were used with slot and non-slot drills. The following groups were compared: group 1, MI surgical guide with slot drill; group 2, MI surgical guide with a non-slot drill; and group 3, MF surgical guide with a slot drill. A constant-temperature water bath at 36℃ was used. The drilling was performed in 6 stages, and the initial, highest, and lowest temperatures of the cortical bone were measured at each stage using a non-contact infrared thermometer. Results: There were no temperature increases above the initial temperature in any drilling procedure. The only significant difference between the non-slot and slot groups was observed with the use of the first drill in the MI group, with a higher temperature in the non-slot group (P=0.012). When the heat generation during the first and the second drilling was compared in the non-slot group, the heat generation during the first drilling was significantly higher (P<0.001), and there was no significant difference in heat generation between the drills in the slot group. Conclusions: Within the limitations of this study, implant-site preparation with the surgical guide showed no critical increase in the temperature of the cortical bone, regardless of whether there was a slot in the drill. In particular, the slotted drill had a cooling effect during the initial drilling.

• Journal of Pharmaceutical Investigation
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• 제40권3호
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• pp.139-153
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• 2010

Nitrosative stress is defined as pathophysiological conditions that are related to covalent modifications of proteins by nitration/nitrosylation by forms of nitrogen oxide ($NO_x$), leading to DNA damage, ultimately, cell death. This type of stress condition appears to be associated with a number of disease states, including diabetes, inflammation and neurodegenerative diseases. Since these pathological conditions are frequently chronic in nature and, thus, require long-term treatment, changes in pharmacokinetics are likely to affect the therapy. Transporters are membrane proteins that facilitate the movement of substrates, including drugs, across plasma membranes of epithelial / endothelial cells. Since it is now increasingly evident that transporters are pharmacokinetically significant, functional alteration of transporters by this stress condition may have therapeutic relevance. In this review, experimental techniques that are used to study both in vivo and in vitro nitrosative stress are summarized and discussed, along with available literature information on the functional implication of transporters under conditions of nitrosative stress conditions. In the literature, both functional induction and impa irment were apparently present for both drug transporter families [i.e., ATP-binding cassette (ABC) and solute carrier families (SLC)]. Furthermore, a change in the function of a certain transporter appears to have temporal dependency by impairment in the early phase of nitrosative stress and induction thereafter, suggesting that the role of nitrosative stress is complex in terms of functional implications of the transporters. Although the underlying mechanisms for these alterations are not fully understood, protein nitration/nitrosylation appears to be involved in the functional impairment whereas transcript factor(s) activated by nitrosative stress may play a role, at least in part, in functional induction. Interestingly, functional induction under conditions of nitrosative stress has not been observed for SLC transporters while such impairment has been documented for both ABC and SLC transporters. Further investigations appear to be necessary to fully delineate the underlying reasons for these differences on the impact and importance of nitrosative stress conditions.

• 한국동물생명공학회지
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• 제37권2호
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• pp.67-79
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• 2022

Currently, there is no treatment to reverse or cure heart failure caused by ischemic heart disease and myocardial infarction despite the remarkable advances in modern medicine. In addition, there is a lack of evidence regarding the existence of stem cells involved in the proliferation and regeneration of cardiomyocytes in adult hearts. As an alternative solution to overcome this problem, protocols for differentiating human pluripotent stem cell (hPSC) into cardiomyocyte have been established, which further led to the development of cell therapy in major leading countries in this field. Recently, clinical studies have confirmed the safety of hPSC-derived cardiac progenitor cells (CPCs). Although several institutions have shown progress in their research on cell therapy using hPSC-derived cardiomyocytes, the functions of cardiomyocytes used for transplantation remain to be those of immature cardiomyocytes, which poses a risk of graft-induced arrhythmias in the early stage of transplantation. Over the last decade, research aimed at achieving maturation of immature cardiomyocytes, showing same characteristics as those of mature cardiomyocytes, has been actively conducted using various approaches at leading research institutes worldwide. However, challenges remain in technological development for effective generation of mature cardiomyocytes with the same properties as those present in the adult hearts. Therefore, in this review, we provide an overview of the technological development status for maturation methods of hPSC-derived cardiomyocytes and present a direction for future development of maturation techniques.