Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
 
Articles by Y. S Lee
Total Records ( 12 ) for Y. S Lee
  H. O Byun , N. K Han , H. J Lee , K. B Kim , Y. G Ko , G Yoon , Y. S Lee , S. I Hong and J. S. Lee
 

Induction of premature senescence may be a promising strategy for cancer treatment. However, biomarkers for senescent cancer cells are lacking. To identify such biomarkers, we performed comparative proteomic analysis of MCF7 human breast cancer cells undergoing cellular senescence in response to ionizing radiation (IR). IR-induced senescence was associated with up-regulation of cathepsin D (CD) and down-regulation of eukaryotic translation elongation factor 1β2 (eEF1B2), as confirmed by Western blot. The other elongation factor, eukaryotic translation elongation factor 11 (eEF1A1), was also down-regulated. IR-induced senescence was associated with similar changes of CD and eEF1 (eEF1A1 and eEF1B2) levels in the HCT116 colon cancer cell line and the H460 lung cancer cell line. Up-regulation of CD and down-regulation of eEF1 seemed to be specific to senescence, as they were observed during cellular senescence induced by hydrogen peroxide or anticancer drugs (camptothecin, etoposide, or 50 ng doxorubicin) but not during apoptosis induced by Taxol or 10 µg doxorubicin or autophagy induced by tamoxifen. The same alterations in CD and eEF1A1 levels were observed during replicative senescence and Ras oncogene-induced senescence. Transient cell cycle arrest did not alter levels of eEF1 or CD. Chemical inhibition of CD (pepstatin A) and small interfering RNA–mediated knockdown of CD and eEF1 revealed that these factors participate in cell proliferation. Finally, the senescence-associated alteration in CD and eEF1 levels observed in cell lines was also observed in IR-exposed xenografted tumors. These findings show that CD and eEF1 are promising markers for the detection of cellular senescence induced by a variety of treatments. [Cancer Res 2009;69(11):4638–47]

  Y. S Park , J. H Park , S. H Kim , M. H Lee , Y. S Lee , S. C Yang and J. S. Kang
 

Limaprost, a prostaglandin E1 analogue, with a strong vasodilatory and antiplatelet activity has been used to release from the symptoms of thromboangiitis obliterans (TAO), which is more prevalent in Korea and Japan, and lumbar spinal canal stenosis (LSCS). In spite of many uses of limaprost, the pharmacokinetics (PK) of it has not been studied in the Korean population. Therefore, a preliminary PK study was designed at a clinical oral dosage of 30-µg limaprost in 5 healthy Korean volunteers. Blood samples were obtained at 14 consecutive time points for 12 hours after dosing and analyzed by liquid chromatography—tandem mass spectrometry with electrospray ionization (LC-ESI/MS/ MS) at a very low detection limit of 0.5 pg/mL of limaprost in human plasma with considerably short run time (18 minutes). Pharmacokinetic characteristics resulted in ‘‘time for maximal concentrations (Tmax 0.5 hour),’’ ‘‘elimination half-life (T1/2 1.64 hours),’’ ‘‘maximal concentration (Cmax 13.37 pg/mL),’’ ‘‘area under the curve (AUC12 hours 18.60 pg · h/mL),’’ ‘‘AUC extrapolated to infinity (AUCinfinity 22.98 pg · h/mL),’’ ‘‘extrapolation (AUCinfinity — 12 hours/AUCinfinity 0.15%),’’ ‘‘elimination rate constant (ke 0.68 h—1),’’ ‘‘systemic clearance (CL 1.77 L/h),’’ and ‘‘mean residence time (MRT 1.74 hours).’’ These results showed that orally administered 30-µg limaprost was rapidly and highly absorbed, and it was considerably eliminated fast from the blood stream in the healthy Korean volunteers.

  Y. S Lee , K. S Kim and S. G. Chang
  No Description
  Y. S Lee , Y Shibata , A Malhotra and A. Dutta
 

New types of small RNAs distinct from microRNAs (miRNAs) are progressively being discovered in various organisms. In order to discover such novel small RNAs, a library of 17- to 26-base-long RNAs was created from prostate cancer cell lines and sequenced by ultra-high-throughput sequencing. A significant number of the sequences are derived from precise processing at the 5' or 3' end of mature or precursor tRNAs to form three series of tRFs (tRNA-derived RNA fragments): the tRF-5, tRF-3, and tRF-1 series. These sequences constitute a class of short RNAs that are second most abundant to miRNAs. Northern hybridization, quantitative RT–PCR, and splinted ligation assays independently measured the levels of at least 17 tRFs. To demonstrate the biological importance of tRFs, we further investigated tRF-1001, derived from the 3' end of a Ser-TGA tRNA precursor transcript that is not retained in the mature tRNA. tRF-1001 is expressed highly in a wide range of cancer cell lines but much less in tissues, and its expression in cell lines was tightly correlated with cell proliferation. siRNA-mediated knockdown of tRF-1001 impaired cell proliferation with the specific accumulation of cells in G2, phenotypes that were reversed specifically by cointroducing a synthetic 2'-O-methyl tRF-1001 oligoribonucleotide resistant to the siRNA. tRF-1001 is generated in the cytoplasm by tRNA 3'-endonuclease ELAC2, a prostate cancer susceptibility gene. Our data suggest that tRFs are not random by-products of tRNA degradation or biogenesis, but an abundant and novel class of short RNAs with precise sequence structure that have specific expression patterns and specific biological roles.

  S. M Ahn , T. H Kim , S Lee , D Kim , H Ghang , D. S Kim , B. C Kim , S. Y Kim , W. Y Kim , C Kim , D Park , Y. S Lee , S Kim , R Reja , S Jho , C. G Kim , J. Y Cha , K. H Kim , B Lee , J Bhak and S. J. Kim
 

We present the first Korean individual genome sequence (SJK) and analysis results. The diploid genome of a Korean male was sequenced to 28.95-fold redundancy using the Illumina paired-end sequencing method. SJK covered 99.9% of the NCBI human reference genome. We identified 420,083 novel single nucleotide polymorphisms (SNPs) that are not in the dbSNP database. Despite a close similarity, significant differences were observed between the Chinese genome (YH), the only other Asian genome available, and SJK: (1) 39.87% (1,371,239 out of 3,439,107) SNPs were SJK-specific (49.51% against Venter's, 46.94% against Watson's, and 44.17% against the Yoruba genomes); (2) 99.5% (22,495 out of 22,605) of short indels (< 4 bp) discovered on the same loci had the same size and type as YH; and (3) 11.3% (331 out of 2920) deletion structural variants were SJK-specific. Even after attempting to map unmapped reads of SJK to unanchored NCBI scaffolds, HGSV, and available personal genomes, there were still 5.77% SJK reads that could not be mapped. All these findings indicate that the overall genetic differences among individuals from closely related ethnic groups may be significant. Hence, constructing reference genomes for minor socio-ethnic groups will be useful for massive individual genome sequencing.

  A. Y Kim , Y. S Lee , K. H Kim , J. H Lee , H. K Lee , S. H Jang , S. E Kim , G. Y Lee , J. W Lee , S. A Jung , H. Y Chung , S Jeong and J. B. Kim
 

In obesity, dysregulation of adipocytokines is involved in several pathological conditions including diabetes and certain cancers. As a member of the adipocytokines, adiponectin plays crucial roles in whole-body energy homeostasis. Recently, it has been reported that the level of plasma adiponectin is reduced in several types of cancer patients. However, it is largely unknown whether and how adiponectin affects colon cancer cell growth. Here, we show that adiponectin suppresses the proliferation of colon cancer cells including HCT116, HT29, and LoVo. In colon cancer cells, adiponectin attenuated cell cycle progression at the G1/S boundary and concurrently increased expression of cyclin-dependent kinase inhibitors such as p21 and p27. Adiponectin stimulated AMP-activated protein kinase (AMPK) phosphorylation whereas inhibition of AMPK activity blunted the effect of adiponectin on the proliferation of colon cancer cells. Furthermore, knockdown of adiponectin receptors such as AdipoR1 and AdipoR2 relieved the suppressive effect of adiponectin on the growth of colon cancer cells. In addition, adiponectin repressed the expression of sterol regulatory element binding protein-1c, which is a key lipogenic transcription factor associated with colon cancers. These results suggest that adiponectin could inhibit the growth of colon cancer cells through stimulating AMPK activity.

  S. J Lee , Y. S Lee , T. A Zimmers , A Soleimani , M. M Matzuk , K Tsuchida , R. D Cohn and E. R. Barton
 

Myostatin is a TGF-β family member that normally acts to limit skeletal muscle mass. Follistatin is a myostatin-binding protein that can inhibit myostatin activity in vitro and promote muscle growth in vivo. Mice homozygous for a mutation in the Fst gene have been shown to die immediately after birth but have a reduced amount of muscle tissue, consistent with a role for follistatin in regulating myogenesis. Here, we show that Fst mutant mice exhibit haploinsufficiency, with muscles of Fst heterozygotes having significantly reduced size, a shift toward more oxidative fiber types, an impairment of muscle remodeling in response to cardiotoxin-induced injury, and a reduction in tetanic force production yet a maintenance of specific force. We show that the effect of heterozygous loss of Fst is at least partially retained in a Mstn-null background, implying that follistatin normally acts to inhibit other TGF-β family members in addition to myostatin to regulate muscle size. Finally, we present genetic evidence suggesting that activin A may be one of the ligands that is regulated by follistatin and that functions with myostatin to limit muscle mass. These findings potentially have important implications with respect to the development of therapeutics targeting this signaling pathway to preserve muscle mass and prevent muscle atrophy in a variety of inherited and acquired forms of muscle degeneration.

  J. H Ahn , Y. S Lee , H. C Ha , J. S Shim and K. S. Lim
  Background

In the symptomatic discoid lateral meniscus, the effectiveness of preoperative magnetic resonance imaging (MRI) is not well documented.

Hypothesis

Magnetic resonance imaging classification will provide more information to the surgeon in choosing the appropriate treatment methods with the help of arthroscopic findings.

Study design

Cohort study (diagnosis); Level of evidence, 2.

Methods

Sixty-seven patients (82 knees) were reviewed. The preoperative MRI was checked in 76 of 82 knees. The Lysholm and Ikeuchi grading scales were evaluated. Images were analyzed from MRI, and findings were classified into 4 categories: no shift, anterocentral shift, posterocentral shift, and central shift. Tear pattern classifications were based on arthroscopic findings: horizontal tear, peripheral tear, horizontal and peripheral tear, posterolateral corner loss, and others. The correlations between MRI classification tear patterns and surgical methods were analyzed using the chi-square test or the Fisher exact test. The sensitivity, specificity, and accuracy of shift in preoperative MRI—according to the existence of peripheral tear when corroborated with arthroscopy—were also analyzed with the chi-square test. Inter- and intraobserver reliability was statistically analyzed by producing the inter- and intraclass correlation coefficient.

Results

The mean preoperative Lysholm score was 77.3 (range, 43–97), and the last follow-up Lysholm score had increased to 96.8 (range, 84–100; P < .001). At last follow-up (100% follow-up), the Ikeuchi grading scale scored 48 knees as excellent, 30 as good, and 4 as fair. According to the MRI classification, 43 knees were no shift; 6, anterocentral shift; 15, posterocentral shift; and 12, central shift. Shift-type knees had a significantly larger number of peripheral tears, and repairs were performed in the shift-type knees (55%) more frequently than in the no-shift-type knees (28%). Among 82 knees, 31 were repaired simultaneously after a central partial meniscectomy.

Conclusion

Magnetic resonance imaging classification provides more information to surgeons in choosing the appropriate treatment methods, although the final decision regarding procedure is made during arthroscopy after thorough analysis of the tear.

  B. O Lim , Y. S Lee , J. G Kim , K. O An , J Yoo and Y. H. Kwon
  Background

Female athletes have a higher risk of anterior cruciate ligament injury than their male counterparts who play at similar levels in sports involving pivoting and landing.

Hypothesis

The competitive female basketball players who participated in a sports injury prevention training program would show better muscle strength and flexibility and improved biomechanical properties associated with anterior cruciate ligament injury than during the pretraining period and than posttraining parameters in a control group.

Study Design

Controlled laboratory study.

Methods

A total of 22 high school female basketball players were recruited and randomly divided into 2 groups (the experimental group and the control group, 11 participants each). The experimental group was instructed in the 6 parts of the sports injury prevention training program and performed it during the first 20 minutes of team practice for the next 8 weeks, while the control group performed their regular training program. Both groups were tested with a rebound-jump task before and after the 8-week period. A total of 21 reflective markers were placed in preassigned positions. In this controlled laboratory study, a 2-way analysis of variance (2 x 2) experimental design was used for the statistical analysis (P < .05) using the experimental group and a testing session as within and between factors, respectively. Post hoc tests with Sidak correction were used when significant factor effects and/or interactions were observed.

Results

A comparison of the experimental group’s pretraining and posttraining results identified training effects on all strength parameters (P = .004 to .043) and on knee flexion, which reflects increased flexibility (P = .022). The experimental group showed higher knee flexion angles (P = .024), greater interknee distances (P = .004), lower hamstring-quadriceps ratios (P = .023), and lower maximum knee extension torques (P = .043) after training. In the control group, no statistical differences were observed between pretraining and posttraining findings (P = .084 to .873). At pretraining, no significant differences were observed between the 2 groups for any parameter (P = .067 to .784). However, a comparison of the 2 groups after training revealed that the experimental group had significantly higher knee flexion angles (P = .023), greater knee distances (P = .005), lower hamstring-quadriceps ratios (P = .021), lower maximum knee extension torques (P = .124), and higher maximum knee abduction torques P (= .043) than the control group.

Conclusion

The sports injury prevention training program improved the strength and flexibility of the competitive female basketball players tested and biomechanical properties associated with anterior cruciate ligament injury as compared with pretraining parameters and with posttraining parameters in the control group.

Clinical Relevance

This injury prevention program could potentially modify the flexibility, strength, and biomechanical properties associated with ACL injury and lower the athlete’s risk for injury.

  J. H Ahn , J. H Bae , Y. S Lee , K Choi , T. S Bae and J. H. Wang
  Background

An anterolateral approach to the tibial tunnel of posterior cruciate ligament reconstruction is used to reduce the sharpness of the graft-tunnel angle, the so-called killer turn effect. However, with the anterolateral approach, the tunnel might be widened into an ovoid shape because of the small angle between the tunnel and the anterolateral cortex.

Hypothesis

The fixation strength of the posterior cruciate ligament graft in the tibial tunnel will be weaker in the anterolateral approach compared with the anteromedial approach.

Study Design

Controlled laboratory study.

Methods

Twenty paired cadaveric tibias were used. Tibial tunnels were made using following approaches: an anteromedial approach for 10 tibias and an anterolateral approach for 10 tibias. The anterior cortex-tunnel angle and the diameter of the tunnel entrance were measured by 2-dimensional computed tomographic scans. After fixation of the Achilles tendon allograft with a biodegradable screw, the maximal strength of the graft at failure was measured using a materials testing machine.

Results

The mean cortex-tunnel angle was 47.5° ± 9.3° in the anteromedial approach group and 28.3° ± 7.4° in the anterolateral approach group. The mean long diameter of the tunnels in the anteromedial approach group was 10.6 ± 1.0 mm and in the anterolateral approach group it was 14.0 ± 1.5 mm. These two parameters showed statistically significant differences between the 2 groups (P < .01). The mean maximum load at failure for the anteromedial approach group was 385.4 ± 139.7 N, and for the anterolateral approach group it was 225.1 ± 144.1 N. This difference was statistically significant (P = .021).

Conclusion

The anterolateral approach resulted in a tunnel with a wider entrance, a more acute cortex-tunnel angle, and a lower maximal load at failure compared with tunnels created using the anteromedial approach.

Clinical Relevance

The use of additional fixation methods, such as post ties or ligament washers and screws, should be considered when using an anterolateral approach for tibial tunnel of posterior cruciate ligament reconstruction.

  J. H Ahn , Y. S Lee , J. C Yoo , M. J Chang , K. H Koh and M. H. Kim
  Background

Tears of the medial meniscus posterior horn (MMPH) are frequently found in knees with deficient anterior cruciate ligaments (ACLs). There are few studies that have evaluated healing of the menisci and the factors associated with healing.

Hypothesis

The repaired menisci would show good healing in the knees with reconstructed ACLs, and the healing capacity of the menisci would differ according to the size, type, and location of the tear as well as the age and gender.

Study Design

Case series; Level of evidence, 4.

Methods

From August 1997 to February 2007, 311 knees underwent MMPH repair using either a modified all-inside or inside-out technique with concomitant ACL reconstruction. Among these patients, a second-look arthroscopy was performed at a mean of 37.7 months postoperatively (range, 12–128 months) in 140 patients. Clinical parameters and outcomes were evaluated. The repaired menisci were divided into complete, incomplete, and failure-to-heal groups. The factors associated with meniscal healing were statistically assessed.

Results

Among 140 patients, 118 (84.3%) showed complete healing, 17 (12.1%) had incomplete healing, and 5 (3.6%) failed to heal. The clinical success rate was 96.4% (135/140) because patients in the incomplete group showed no clinical symptoms associated with meniscal tears. Healing was associated with the tear location (P <.001) and type of tear (P =.0237) on the univariate analysis and the location (P =.0401) only on the multivariate analysis.

Conclusion

Repaired MMPH tears in knees with reconstructed ACLs healed without complications and had satisfactory clinical results. The tear location and type were factors associated with healing on the univariate analysis and location only on the multivariate analysis.

  J. K Ha , J. C Shim , D. W Kim , Y. S Lee , H. J Ra and J. G. Kim
 

Background: Meniscus allograft transplantation (MAT) is useful for meniscus-deficient knees. Although meniscal extrusion is common after MAT, there is no consensus regarding the criteria for normal meniscal extrusion or the relationship between clinical and radiologic results.

Hypothesis: Meniscal extrusion after MAT results in poor clinical, radiologic, and arthroscopic outcomes.

Study Design: Case series; Level of evidence, 4.

Methods: Thirty-six of 60 patients undergoing MAT from September 2002 to June 2007 who were available for follow-up evaluation for more than 2 years were evaluated. The study population (31 men, 5 women) consisted of 15 and 21 cases of medial and lateral meniscus transplant, respectively. Knee status was evaluated by Lysholm score, plain radiography, and magnetic resonance imaging preoperatively and postoperatively. Second-look examinations were performed in 18 cases.

Results: Mean follow-up was 31.4 months (range, 24-36). Lysholm knee score increased significantly (mean, 88.2; range, 70-100) on final visit versus the preoperative value (mean, 61.2; range, 26-83; P < .001). Joint-space narrowing was 0.08 mm (range, –2.58 to 1.92) in extension AP and –0.09 mm (range, –2.3 to 1.8) in Rosenberg view. Kellgren-Lawrence arthrosis grade did not change in 28 knees (77.8%) and progressed by 1 grade in 8 knees. Meniscal extrusion extent was 3.87 ± 1.94 mm and relative percentage extrusion was 42.1% ± 17.7%. Seven cases (19.4%) showed minor extrusion (<3 mm), 27 (75%) showed major extrusion (>3 mm), and 2 (5.6%) showed no extrusion. Further degeneration was absent in 28 knees (77.8%) on magnetic resonance imaging. In second-look arthroscopic examinations at an average of 26.3 months, 11 of 18 (63.6%) cases showed no progression of cartilage degeneration. There was no significant correlation between meniscal extrusion and other parameters.

Conclusion: This study indicated that MAT can improve the clinical status of the meniscectomized knee. Although meniscal extrusion occurred after surgery in most cases, there was no significant correlation with various clinical, radiologic, or arthroscopic outcomes. Further studies are required to evaluate long-term effects of meniscal extrusion.

 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility