S C Lee

Sunchon National University, Sunchun, South Jeolla, South Korea

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Publications (34)68.41 Total impact

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    ABSTRACT: A cryopreservation protocol has been developed for embryogenic callus cultures of castor aralia (Kalopanax septemlobus), a deciduous tree which is widely used in oriental medicine and in landscape design. Three preculture treatments, four loading and six vitrification solutions were tested in a vitrification procedure. Preculture of embryogenic callus (EC) with high sucrose concentrations (up to 0.7 M) showed no effect on regrowth after cryopreservation. Loading for 20 min at ambient temperature improved regrowth of cryopreserved EC by 70-75 percent compared with non-loaded samples, regardless of the composition of the loading solution. Among vitrification solutions, the highest regrowth of 95-100 percent after cryopreservation was obtained after incubation of EC in a vitrification solution A3-80 percent comprising (w/v) 33.3 percent glycerol + 13.3 percent DMSO + 13.3 percent EG + 20.1 percent sucrose for 40 min at 0°C. Profiling of crystallization and recrystallization events using differential scanning calorimetry (DSC) confirmed that freezing injury was minimized in samples after loading and cryoprotection with this vitrification solution. Unlike many other papers, the droplet-vitrification protocol did not produce higher post-cryopreservation regrowth of Kalopanax EC, compared with the vitrification procedure. When samples are sufficiently cryoprotected during VS treatment, vitrification using cryovials may be preferred, since droplet-vitrification is more complex and requires skilled personnel. Cryopreserved callus grew rapidly and produced numerous somatic embryos, which developed similarly to embryos obtained from non-cryopreserved samples.
    Cryo letters 09/2012; 33(5):402-10. · 0.64 Impact Factor
  • H H Kim, S C Lee
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    ABSTRACT: Although an appropriate cryopreservation protocol is a prerequisite for basic studies and large-scale implementation as well as further cryopreservation studies, the process relies on trial and error. Among the vitrification-based cryopreservation techniques, droplet-vitrification produces high post-cryopreservation recovery. However, the protocol itself cannot solve the problems engaged in plant cryopreservation, prominently due to dehydration with cytotoxic vitrification solutions. This paper proposes a set of treatments to develop droplet-vitrification using a standard procedure associated with additional treatments and alternative vitrification solutions. The proposed standard protocol consists of a progressive preculture with 0.3 M sucrose for 31 h and with 0.7 M for 17 h, loading with vitrification solution C4-35% (17.5 percent glycerol + 17.5 percent sucrose, w/v) for 20 to 40 min, dehydration with vitrification solutions A3-90 percent (37.5 percent glycerol + 15% DMSO + 15 percent EG + 22.5 percent sucrose) for 10 to 30 min or B1-100 percent (PVS3) for 40 to 120 min at room temperature, cooling the samples using aluminum foil strips, rewarming by plunging into pre-heated (40 degree C) unloading solution (0.8 M sucrose) and further unloading for 20 to 60 min, depending on size and permeability of the materials. Using this systematic approach we can identify whether the material is tolerant or sensitive to chemical toxicity and to the osmotic stress of dehydration with vitrification solutions, thus revealing which is the main barrier in solution-based vitrification methods. Based on the sensitivity of samples we can design a droplet-vitrification procedure, i.e. preculture, loading, dehydration with vitrification solutions, cooling and rewarming. Using this approach, the development of appropriate droplet-vitrification protocol is facilitated.
    Cryo letters 01/2012; 33(4):271-9. · 0.64 Impact Factor
  • Biology of Blood and Marrow Transplantation 02/2011; 17(2). · 3.35 Impact Factor
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    ABSTRACT: To evaluate the relationship of axial length (AXL), intraoperatively assessed posterior vitreous detachment (PVD) status, and surgical outcomes of diabetic vitrectomy. Retrospective, consecutive case series. Clinical records were reviewed for 115 eyes (50 males, 65 females) with more than a 6-month follow-up who underwent diabetic vitrectomy from a single surgeon. Thirty-three eyes had vitreous haemorrhage, 37 had tractional retinal detachment (TRD) threatening the macula, 43 had TRD involving the macula, and two had neovascular glaucoma. AXL was measured preoperatively by ultrasonography, and PVD status was classified intraoperatively: broad vitreo-retinal adhesion as no PVD, PVD at the macular area with attachment at the disc as incomplete PVD, and complete PVD. Forty-four eyes had no PVD, 23 had incomplete PVD, and 48 had complete PVD. A majority of the no PVD group had macula off TRD (97.7%), whereas vitreous haemorrhage (68.7%) predominated in the complete PVD group. Longer AXLs were noted in the complete PVD group compared with the no PVD and incomplete PVD groups (ANOVA in three groups P=0.0001). Univariate analysis showed that AXL had an influence on anatomical success (P=0.02). Multiple logistic regression analysis yielded that PVD status is a significant predictor of the final best corrected visual acuity (BCVA)>20/100, and BCVA>20/40 (P=0.01, P=0.02). Intraoperatively assessed PVD status is a prognostic factor for functional outcomes of diabetic vitrectomy. Shorter AXL was associated with lesser PVD. In eyes with a lack of PVD, careful timing and decision of surgery are mandatory.
    Eye (London, England) 07/2010; 24(7):1273-8. · 1.97 Impact Factor
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    ABSTRACT: Anesthetic titration using spectral entropy monitoring reduces anesthetic requirements and shortens recovery in adult surgical patients. This study was performed to evaluate the effect of entropy monitoring on end-tidal sevoflurane concentration and recovery characteristics in pediatric patients undergoing sevoflurane anesthesia. Seventy-eight children (aged 3-12 years) scheduled for a tonsillectomy and/or an adenoidectomy were randomly divided into one of two groups: standard practice (Standard) or entropy-guided (Entropy). In the Standard group, sevoflurane was adjusted to maintain the heart rate and systolic blood pressure (BP) within 20% of the baseline values. In the Entropy group, sevoflurane was adjusted to achieve a state entropy of 40-50. We compared the entropy values, end-tidal sevoflurane concentration and recovery times between groups. During maintenance of anesthesia, the entropy and BP values were higher in the Entropy group (P<0.05). The end-tidal sevoflurane concentration during maintenance was lower in the Entropy group (2.2 (0.3) vol%) compared with the Standard group (2.6 (0.4) vol%) (P<0.05). Recovery times were faster in the Entropy group (P<0.05). Compared with standard practice, we found that entropy-guided anesthetic administration was associated with a reduced sevoflurane concentration and a slightly faster emergence and recovery in 3-12-year-old children.
    Acta Anaesthesiologica Scandinavica 02/2010; 54(7):859-62. · 2.36 Impact Factor
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    ABSTRACT: Low serum nerve growth factor (NGF) levels have been reported in patients with diabetic peripheral neuropathy (DPN), but the role of NGF in the development of neuropathy is unclear. Thus, we investigated the associations of serum NGF level and NGF receptor activity with the presence and severity of DPN. One hundred and thirty-six patients with Type 2 diabetes were included in this cross-sectional study. Serum NGF levels were measured by ELISA. Expressions of NGF receptors (TrkA and p75(NTR)) were measured by immunohistochemical staining. The presence and severity of DPN were assessed by neuropathy disability score (NDS) and by corneal nerve fibre length (cNFL) and nerve branch density (cNBD) using in vivo confocal microscopy. Patients with DPN had higher serum NGF levels (56-451 pg/ml) than patients without DPN (4-54 pg/ml). However, in DPN patients, serum NGF was negatively associated with neuropathy severity (mild 222 +/- 64 pg/ml; moderate 114 +/- 17 pg/ml; severe 89 +/- 20 pg/ml). This negative association was consistent in all severity indices (NDS, P < 0.001; cNFL, P < 0.001; cNBD P = 0.010) even after adjustment for age, sex, diabetes duration, insulin use, fasting glucose and glycated haemoglobin. Although NGF receptor activities had significantly (P < 0.05) negative associations with the presence and severity of neuropathy, these associations were not significant when adjusted for other factors. Serum NGF level was positively associated with the presence of DPN but negatively associated with neuropathy severity in DPN patients. The change in serum NGF might be a consequence of, rather than a contributor to, the early development of DPN.
    Diabetic Medicine 12/2009; 26(12):1228-34. · 3.24 Impact Factor
  • Source
    J H Bae, S C Lee
    Eye (London, England) 07/2009; 24(4):735. · 1.97 Impact Factor
  • The British journal of ophthalmology 07/2009; 93(6):836-7. · 2.92 Impact Factor
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    ABSTRACT: In plant vitrification protocols, the loading treatment, which involves treating the explants with a moderately concentrated cryoprotectant solution, precedes dehydration of explants with highly concentrated vitrification solutions in order to reduce the toxicity which can be induced by their direct exposure to such highly concentrated solutions. This study aimed at developing alternative loading solutions composed of mixtures of glycerol and sucrose at various concentrations. Differential scanning calorimetry runs of loading solutions and of loaded and dehydrated explants were performed to assay thermal events occurring during cooling and warming. These loading solutions were applied to two model species, viz. garlic and chrysanthemum which were cryopreserved using a droplet-vitrification procedure. The loading treatment proved to be beneficial to both garlic and chrysanthemum and increased recovery of cryopreserved explants. However, response to the loading solutions tested varied between the two model species employed: with garlic, all the loading solutions had a similar effect, whereas survival of chrysanthemum shoot tips was significantly influenced by the composition of the loading solution employed. A loading solution comprising 1.9 M glycerol and 0.5 M sucrose was the most effective. The loading treatment may thus act as an osmotic stress neutralizer and/or induce the physiological adaptation of tissues and cells, including membranes, to both dehydration and freezing.
    Cryo letters 01/2009; 30(4):291-9. · 0.64 Impact Factor
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    W K Song, W I Yang, S C Lee
    Eye (London, England) 08/2008; 23(6):1486-8. · 1.97 Impact Factor
  • European Journal of Anaesthesiology 01/2007; 24. · 3.01 Impact Factor
  • European Journal of Anaesthesiology 01/2007; 24. · 3.01 Impact Factor
  • European Journal of Anaesthesiology 01/2006; 23. · 3.01 Impact Factor
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    Eye 08/2004; 18(7):745-6. · 1.90 Impact Factor
  • European Journal of Anaesthesiology 01/2004; 21. · 3.01 Impact Factor
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    ABSTRACT: Modification of thermo-mechanical properties of simulated (SiC) silicon carbide-, (ZrO2) zirconia- and (MgAl2O4) spinel-based inert matrix nuclear fuels after cyclic thermal shock was analyzed in terms of Vickers hardness (HV), fracture toughness (KIC) and thermal conductivity. Three different simulated specimens were used for the experiment; a solid solution of yttria-stabilized zirconia and ceria (composition: Er0.07Y0.10Ce0.15Zr0.68O1.915, 92.0% TD, specimen hereafter called Ce–ZrO2), a CeO2-dispersed Mg-spinel (composition: 15wt%CeO2–MgAl2O4, 93.7% TD, specimen hereafter called Ce-spinel) and a CeO2-dispersed silicon carbide (composition: 80.8 wt% SiC, 6.9 wt% Al2O3, 5.1 wt% Y2O3 and 5.0 wt% CeO2, specimen hereafter called Ce–SiC), CeO2 being surrogate materials for PuO2. Cyclic thermal shock experiment and thermal conductivity measurements were simultaneously carried out by heating disc-shaped specimens up to maximum temperature ranging from 1073 to 1673 K and then cooling down to 343 K with Ar gas during 20–25 min. The Vickers hardness of the three different thermally shocked specimens showed nearly constant values with increasing number of cycles, except for the specimen heated at 1673 K. The KIC values of the corresponding specimens increased with the increasing number of cyclic thermal shock at 1673 K. For Ce–ZrO2 heated at 1673 K, however, it decreases considerably due to the combined effects of formation of second phase and modification of the matrix composition thereby. The calculated thermal conductivity of Ce-spinel decreases as the number of cycles in thermal shock increases in the temperature range between 1073 and 1673 K, and Ce–SiC slightly decreased with the number of cycles in cyclic thermal shock and the variations in thermal conductivity are almost the same for the temperature increases of 1073 and 1373 K, whereas, in Ce–ZrO2, it remains nearly constant.
    Journal of Nuclear Materials 01/2003; 319:15-23. · 2.02 Impact Factor
  • Advanced Engineering Materials 08/2002; 4(8):584-589. · 1.51 Impact Factor
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    ABSTRACT: All-trans-retinoic acid (atRA) is a promising anticancer and antiwrinkle drug. However, its clinical application is limited because it is rapidly metabolized by the induced cytochrome P450 (P450). In this study, farnesol derivatives are proposed as new inhibitors to prevent P450-mediated metabolism. The farnesol derivatives were suc-farnesol and mal-farnesol, which were synthesized by the chemical conjugation of farnesol with succinic anhydride and maleic anhydride, respectively. The inhibition effects of farnesol, farnesoic acid, and farnesol derivatives on the atRA metabolism were evaluated in microsome and in AMC-HN-6 cells. In the microsome experiment, suc-farnesol and mal-farnesol strongly inhibited atRA metabolism at 10(minus;4) mol/L concentration by as much as 61% and 77%, respectively. In the cell experiment, the inhibition effects of farnesol derivatives on the atRA metabolism showed similar tendency as the results in the microsome experiment, even if the effect was somewhat decreased. Effects of farnesoic acid and farnesol, however, were not significant. This research suggests that carboxylic end groups, such as atRA and hydrophobicity, might be important factors causing the higher inhibition effect, and that derivatization of farnesol can be 1 method to develop new inhibitors of atRA metabolism.
    Metabolism 12/2001; 50(11):1356-60. · 3.61 Impact Factor
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    ABSTRACT: Retinal pigment epithelium (RPE) cells of the proliferative vitreoretinopathy (PVR) membrane take on the shape of fibroblasts and participate in fibrosis, thus deviating from the character of epithelial cells. This study was undertaken to evaluate RPE cell transdifferentiation in vitro. During the culture of porcine RPE cells, primary and 10th-passaged RPE cells were investigated for cell growth in response to transforming growth factor (TGF) beta(2), change of phenotype and amount in collagen synthesis as well as expression of alpha-smooth-muscle actin (alpha-SMA). TGF-beta(2) inhibited the proliferation of the primary cultures of RPE cells in a dose-dependent manner, while the spindle-shaped 10th-passaged RPE cells were not inhibited by TGF-beta(2). The 10th-subcultured cells did not show much difference in the quality of collagen synthesis, other than type VIII collagen which was not produced. Collagen synthesis was dose-dependently stimulated by TGF-beta(2). The stimulation by TGF-beta(2) in the 10th-passaged RPE cells was much greater than in primary RPE cells. The 10th-subcultured RPE cells produced substantial alpha-SMA compared to alpha-SMA production by primary RPE cells. These results were also observed by confocal laser microscopy. These findings indicated that RPE metaplasia resulting in a change of biological cell behavior might be a necessary predisposing step in the development of PVR.
    Ophthalmic Research 01/2001; 33(2):80-6. · 1.38 Impact Factor
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    ABSTRACT: The Vickers micro-hardness (HV) was measured by an indentation technique of simulated ZrO2-based Inert Matrix Fuel (IMF) material with a composition of Er0.07Y0.10Ce0.15Zr0.68O1.915 in two different densities on sintered specimens and specimens thermally shocked with the quenching temperature differences (ΔTs) between 473 and 1673 K and compared with those of simulated MOX, namely, U0.92Ce0.08O2. The HV values obtained for two IMF materials were found higher, ranging from 6.37 GPa to about 7.84 GPa, depending on ΔT and the sintered density, than those obtained for the simulated MOX which are quasi-constant in the same range of ΔT with a mean value of 6.37 GPa. The fracture toughness (KIC) was calculated from the measured HV and the crack length, and it was found to exhibit a slight increase with increasing ΔT, ranging between 1.4 and 2.0 MPa m, while that of simulated MOX specimen is ranging between 0.8 and 1.1 MPa m. The thermally shocked specimens were observed with an optical microscope and analyzed in terms of microstructural changes and cracking patterns.
    Progress in Nuclear Energy 01/2001; 38(s 3–4):231–236. · 0.88 Impact Factor

Publication Stats

192 Citations
68.41 Total Impact Points


  • 2012
    • Sunchon National University
      • Department of Well-being Resources
      Sunchun, South Jeolla, South Korea
  • 2010
    • Dong-A University
      Tsau-liang-hai, Busan, South Korea
  • 1999–2010
    • Yonsei University Hospital
      • Department of Internal Medicine
      Sŏul, Seoul, South Korea
  • 2001–2003
    • Korea Atomic Energy Research Institute (KAERI)
      Daiden, Daejeon, South Korea
  • 2000–2002
    • Yonsei University
      • Department of Ophthalmology
      Sŏul, Seoul, South Korea
  • 1998
    • University of Southern California
      • Doheny Eye Institute
      Los Angeles, CA, United States
  • 1988
    • Seoul National University
      Sŏul, Seoul, South Korea