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1.  Alu and LINE-1 Hypomethylation Is Associated with HER2 Enriched Subtype of Breast Cancer 
PLoS ONE  2014;9(6):e100429.
The changes in DNA methylation status in cancer cells are characterized by hypermethylation of promoter CpG islands and diffuse genomic hypomethylation. Alu and long interspersed nucleotide element-1 (LINE-1) are non-coding genomic repetitive sequences and methylation of these elements can be used as a surrogate marker for genome-wide methylation status. This study was designed to evaluate the changes of Alu and LINE-1 hypomethylation during breast cancer progression from normal to pre-invasive lesions and invasive breast cancer (IBC), and their relationship with characteristics of IBC. We analyzed the methylation status of Alu and LINE-1 in 145 cases of breast samples including normal breast tissue, atypical ductal hyperplasia/flat epithelial atypia (ADH/FEA), ductal carcinoma in situ (DCIS) and IBC, and another set of 129 cases of IBC by pyrosequencing. Alu methylation showed no significant changes during multistep progression of breast cancer, although it tended to decrease during the transition from DCIS to IBC. In contrast, LINE-1 methylation significantly decreased from normal to ADH/FEA, while it was similar in ADH/FEA, DCIS and IBC. In IBC, Alu hypomethylation correlated with negative estrogen receptor (ER) status, and LINE-1 hypomethylation was associated with negative ER status, ERBB2 (HER2) amplification and p53 overexpression. Alu and LINE-1 methylation status was significantly different between breast cancer subtypes, and the HER2 enriched subtype had lowest methylation levels. In survival analyses, low Alu methylation status tended to be associated with poor disease-free survival of the patients. Our findings suggest that LINE-1 hypomethylation is an early event and Alu hypomethylation is probably a late event during breast cancer progression, and prominent hypomethylation of Alu and LINE-1 in HER2 enriched subtype may be related to chromosomal instability of this specific subtype.
PMCID: PMC4074093  PMID: 24971511
2.  The Stimulatory Effect of Essential Fatty Acids on Glucose Uptake Involves Both Akt and AMPK Activation in C2C12 Skeletal Muscle Cells 
Essential fatty acid (EFA) is known to be required for the body to function normally and healthily. However, the effect of EFA on glucose uptake in skeletal muscle has not yet been fully investigated. In this study, we examined the effect of two EFAs, linoleic acid (LA) and α-linolenic acid (ALA), on glucose uptake of C2C12 skeletal muscle cells and investigated the mechanism underlying the stimulatory effect of polyunsaturated EFAs in comparison with monounsaturated oleic acid (OA). In palmitic acid (PA)-induced insulin resistant cells, the co-treatment of EFAs and OA with PA almost restored the PA-induced decrease in the basal and insulin-stimulated 2-NBDG (fluorescent D-glucose analogue) uptake, respectively. Two EFAs and OA significantly protected PA-induced suppression of insulin signaling, respectively, which was confirmed by the increased levels of Akt phosphorylation and serine/threonine kinases (PKCθ and JNK) dephosphorylation in the western blot analysis. In PA-untreated, control cells, the treatment of 500 µM EFA significantly stimulated 2-NBDG uptake, whereas OA did not. Phosphorylation of AMP-activated protein kinase (AMPK) and one of its downstream molecules, acetyl-CoA carboxylase (ACC) was markedly induced by EFA, but not OA. In addition, EFA-stimulated 2-NBDG uptake was significantly inhibited by the pre-treatment of a specific AMPK inhibitor, adenine 9-β-D-arabinofuranoside (araA). These data suggest that the restoration of suppressed insulin signaling at PA-induced insulin resistant condition and AMPK activation are involved at least in the stimulatory effect of EFA on glucose uptake in C2C12 skeletal muscle cells.
PMCID: PMC4071179  PMID: 24976766
AMPK; C2C12 cells; Essential fatty acid; Glucose uptake; Insulin signaling
3.  Seasonal variation of effect of air pollution on blood pressure 
Many studies have shown a consistent association between ambient air pollution and an increase in death due to cardiovascular causes. An increase in blood pressure is a common risk factor for a variety of cardiovascular diseases. However, the association between air pollution and blood pressure has not been evaluated extensively.
In this cross‐sectional study, we measured blood pressure in 10 459 subjects who had a health examination from 2001 to 2003, and calculated individual's exposure to ambient levels of air pollutants. To evaluate the relationship between exposure to air pollutants and blood pressure with respect to season, we performed a multiple regression analysis, separately, according to season, controlling for individual characteristics and meteorological variables.
In the warm‐weather season (July–September), particulate air pollutant of <10 μm (PM10) and nitrogen dioxide (NO2) concentrations were significantly associated with measures of blood pressure. During cold weather (October–December), blood pressure was significantly associated with sulphur dioxide (SO2) and ozone (O3) concentrations. The significant association between PM10 or NO2 and blood pressure disappeared during the cold‐weather season.
We found a seasonal variation for the association between ambient air‐pollutant concentrations and blood pressure.
PMCID: PMC2652940  PMID: 17372291
4.  Disease specific characteristics of fetal epigenetic markers for non-invasive prenatal testing of trisomy 21 
Non-invasive prenatal testing of trisomy 21 (T21) is being actively investigated using fetal-specific epigenetic markers (EPs) that are present in maternal plasma. Recently, 12 EPs on chromosome 21 were identified based on tissue-specific epigenetic characteristics between placenta and blood, and demonstrated excellent clinical performance in the non-invasive detection of fetal T21. However, the disease-specific epigenetic characteristics of the EPs have not been established. Therefore, we validated the disease-specific epigenetic characteristics of these EPs for use in non-invasive detection of fetal T21.
We performed a high-resolution tiling array analysis of human chromosome 21 using a methyl-CpG binding domain-based protein (MBD) method with whole blood samples from non-pregnant normal women, whole blood samples from pregnant normal women, placenta samples of normal fetuses, and placenta samples of T21 fetuses. Tiling array results were validated by bisulfite direct sequencing and qPCR.
Among 12 EPs, only four EPs were confirmed to be hypermethylated in normal placenta and hypomethylated in blood. One of these four showed a severe discrepancy in the methylation patterns of T21 placenta samples, and another was located within a region of copy number variations. Thus, two EPs were confirmed to be potential fetal-specific markers based on their disease-specific epigenetic characteristics. The array results of these EPs were consisted with the results obtained by bisulfite direct sequencing and qPCR. Moreover, the two EPs were detected in maternal plasma.
We validated that two EPs have the potential to be fetal-specific EPs which is consistent with their disease-specific epigenetic characteristics. The findings of this study suggest that disease-specific epigenetic characteristics should be considered in the development of fetal-specific EPs for non-invasive prenatal testing of T21.
PMCID: PMC3892082  PMID: 24397966
Trisomy 21; Non-invasive prenatal testing; Epigenetic markers
5.  Three cases of glycogenic hepatopathy mimicking acute and relapsing hepatitis in type I diabetes mellitus 
Clinical and molecular hepatology  2013;19(4):421-425.
Glycogenic hepatopathy (GH) is an uncommon cause of serum transaminase elevation in type I diabetes mellitus (DM). The clinical signs and symptoms of GH are nonspecific, and include abdominal discomfort, mild hepatomegaly, and transaminase elevation. In this report we describe three cases of patients presenting serum transaminase elevation and hepatomegaly with a history of poorly controlled type I DM. All of the cases showed sudden elevation of transaminase to more than 30 times the upper normal range (like in acute hepatitis) followed by sustained fluctuation (like in relapsing hepatitis). However, the patients did not show any symptom or sign of acute hepatitis. We therefore performed a liver biopsy to confirm the cause of liver enzyme elevation, which revealed GH. Clinicians should be aware of GH so as to prevent diagnostic delay and misdiagnosis, and have sufficient insight into GH; this will be aided by the present report of three cases along with a literature review.
PMCID: PMC3894443  PMID: 24459648
Glycogen hepatopathy; Transaminase; Type I diabetes mellitus
6.  Non-Invasive Prenatal Testing of Trisomy 18 by an Epigenetic Marker in First Trimester Maternal Plasma 
PLoS ONE  2013;8(11):e78136.
Quantification of cell-free fetal DNA by methylation-based DNA discrimination has been used in non-invasive prenatal testing of fetal chromosomal aneuploidy. The maspin (Serpin peptidase inhibitor, clade B (ovalbumin), member 5; SERPINB5) gene, located on chromosome 18q21.33, is hypomethylated in the placenta and completely methylated in maternal blood cells. The objective of this study was to evaluate the accuracy of non-invasive detection of fetal trisomy 18 using the unmethylated-maspin (U-maspin) gene as a cell-free fetal DNA marker and the methylated-maspin (M-maspin) gene as a cell-free total DNA marker in the first trimester of pregnancy.
Methodology/Principal Findings
A nested case-control study was conducted using maternal plasma collected from 66 pregnant women, 11 carrying fetuses with trisomy 18 and 55 carrying normal fetuses. Median U-maspin concentrations were significantly elevated in women with trisomy 18 fetuses compared with controls (27.2 vs. 6.7 copies/mL; P<0.001). Median M-maspin concentrations were also significantly higher in women with trisomy 18 fetuses than in controls (96.9 vs. 19.5 copies/mL, P<0.001). The specificities of U-maspin and M-maspin concentrations for non-invasive fetal trisomy 18 detection were 96.4% and 74.5%, respectively, with a sensitivity of 90.9%.
Our results suggest that U-maspin and M-maspin concentrations may be useful as potential biomarkers for non-invasive detection of fetal trisomy 18 in the first trimester of pregnancy, irrespective of the sex and genetic variations of the fetus.
PMCID: PMC3815335  PMID: 24223769
7.  Targeting the Transforming Growth Factor-β Signaling in Cancer Therapy 
Biomolecules & Therapeutics  2013;21(5):323-331.
TGF-β pathway is being extensively evaluated as a potential therapeutic target. The transforming growth factor-β (TGF-β) signaling pathway has the dual role in both tumor suppression and tumor promotion. To design cancer therapeutics successfully, it is important to understand TGF-β related functional contexts. This review discusses the molecular mechanism of the TGF-β pathway and describes the different ways of tumor suppression and promotion by TGF-β. In the last part of the review, the data on targeting TGF-β pathway for cancer treatment is assessed. The TGF-β inhibitors in pre-clinical studies, and Phase I and II clinical trials are updated.
PMCID: PMC3825194  PMID: 24244818
Transforming growth factor-β (TGF-β); EW-7197; ALK5; Breast cancer; Metastasis
8.  Evolutionary Pathways in BRCA1-Associated Breast Tumors 
Cancer discovery  2012;2(6):503-511.
BRCA1-associated breast tumors display loss of BRCA1 and frequent somatic mutations of PTEN and TP53. Here we describe the analysis of BRCA1, PTEN, and p53 at the single cell level in 55 BRCA1-associated breast tumors and computational methods to predict the relative temporal order of somatic events, on the basis of the frequency of cells with single or combined alterations. Although there is no obligatory order of events, we found that loss of PTEN is the most common first event and is associated with basal-like subtype, whereas in the majority of luminal tumors, mutation of TP53 occurs first and mutant PIK3CA is rarely detected. We also observed intratumor heterogeneity for the loss of wild-type BRCA1 and increased cell proliferation and centrosome amplification in the normal breast epithelium of BRCA1 mutation carriers. Our results have important implications for the design of chemopreventive and therapeutic interventions in this high-risk patient population.
Defining the temporal order of tumor-driving somatic events is critical for early detection, risk stratification, and the design of chemopreventive therapies. Our combined experimental and computational approach reveal that the loss of wild-type BRCA1 may not be the first event in the majority of BRCA1-associated breast tumors and may not be present in all cancer cells within tumors.
PMCID: PMC3738298  PMID: 22628410
9.  First Imported Case of Skin Infection Caused by PVL-positive ST30 Community-Associated Methicillin-Resistant Staphylococcus aureus Clone in a Returning Korean Traveler from the Philippines 
Journal of Korean Medical Science  2013;28(7):1100-1102.
Although pandemic community-associated (CA-) methicillin-resistant Staphylococcus aureus (MRSA) ST30 clone has successfully spread into many Asian countries, there has been no case in Korea. We report the first imported case of infection caused by this clone in a Korean traveler returning from the Philippines. A previously healthy 30-yr-old Korean woman developed a buttock carbuncle while traveling in the Philippines. After coming back to Korea, oral cephalosporin was given by a primary physician without any improvement. Abscess was drained and MRSA strain isolated from her carbuncle was molecularly characterized and it was confirmed as ST30-MRSA-IV. She was successfully treated with vancomycin and surgery. Frequent international travel and migration have increased the risk of international spread of CA-MRSA clones. The efforts to understand the changing epidemiology of CA-MRSA should be continued, and we should raise suspicion of CA-MRSA infection in travelers with skin infections returning from CA-MRSA-endemic countries.
PMCID: PMC3708085  PMID: 23853497
Staphylococcus aureus; Methicillin Resistance; Community-Acquired Infections; Carbuncle; Travel
10.  Molecular and cytogenetic studies of 101 infertile men with microdeletions of Y chromosome in 1,306 infertile Korean men 
To determine the prevalence of Y chromosome microdeletions in infertile Korean men with abnormal sperm counts and to assess the clinical features and frequency of chromosomal abnormalities in Korean patients with microdeletions.
A total of 1,306 infertile men were screened for Y chromosome microdeletions, and 101 of them had microdeletions. These 101 men were then retrospectively studied for cytogenetic evaluation, testicular biopsy and outcomes of IVF and ICSI.
The overall prevalence of Y chromosome microdeletions in infertile men was 7.7 % (101/1,306). Most microdeletions were in the AZFc region (87.1 %), including deletions of AZFbc (24.7 %) and AZFabc (8.9 %). All patients with AZFa, AZFbc and AZFabc deletions had azoospermia, whereas patients with an AZFc deletion usually had low levels of sperm in the ejaculate or in the testis tissues. Chromosomal studies were performed in 99 men with microdeletions, 36 (36.4 %) of whom had chromosomal abnormalities. Among the infertile men with Y chromosome microdeletions in this study, the incidence of chromosomal abnormality was 48.6 % in the azoospermic group and 3.7 % in the oligozoospermic group. Among the 69 patients with microdeletions and available histological results, 100.0 % of the azoospermic group and 85.7 % of the oligozoospermic group had histological abnormalities. The frequency of both chromosomal abnormalities and histological abnormalities was higher in the azoospermic group compared to the oligozoospermic group. Thirty-four ICSI cycles with either testicular (n = 14) or ejaculated spermatozoa (n = 20) were performed in 23 couples with men with AZFc microdeletion. Thirteen clinical pregnancies (39.4 %) were obtained, leading to the birth of 13 babies.
The study results revealed a close relationship between microdeletions and spermatogenesis, although IVF outcome was not significantly affected by the presence of the AZFc microdeletion. Nevertheless, Y chromosome microdeletions have the potential risk of being transmitted from infertile fathers to their offspring by ICSI. Therefore, before using ICSI in infertile patients with severe spermatogenic defects, careful evaluations of chromosomal abnormalities and Y chromosome microdeletions screening should be performed and genetic counseling should be provided before IVF-ET.
PMCID: PMC3370041  PMID: 22456825
Y chromosome microdeletion; Chromosomal abnormality; Azoospermia factor (AZF); Intracytoplasmic sperm injection (ICSI)
11.  A case of mediastinal ectopic thyroid presenting with a paratracheal mass 
Mediastinal ectopic thyroid is a very rare condition, with few reported cases in the literature and no reported cases in Korea. This report describes an asymptomatic 65-year-old man with a right paratracheal mass compressing the superior vena. Additionally, the epidemiology, clinical manifestation, diagnosis, and management of mediastinal ectopic thyroids are discussed. A mediastinal ectopic thyroid should be considered in the differential diagnosis of all mediastinal masses. Surgical excision is recommended for both the diagnosis and treatment of this condition, because of its potential for malignancy and compression of mediastinal structures. This case demonstrates the clinical importance of mediastinal etopic thyroid.
PMCID: PMC3654136  PMID: 23682232
Thyroid dysgenesis; Mediastinum
12.  Klinefelter Syndrome Diagnosed by Prenatal Screening Tests in High-Risk Groups 
Korean Journal of Urology  2013;54(4):263-265.
Klinefelter syndrome is a chromosomal disorder present in 1 out of 400 to 1,000 male newborns in Western populations. Two-thirds of affected newborns show a karyotype of 47,XXY. Few studies have examined the incidence of Klinefelter syndrome in Korea. The aim of this study was to investigate the incidence of Klinefelter syndrome by use of prenatal screening tests.
Materials and Methods
From January 2001 to December 2010, 18,049 pregnant women who had undergone a chromosomal study for fetal anomalies were included. For fetuses that were diagnosed as having Klinefelter syndrome, the patients' medical records were retrospectively reviewed. Both parents' ages, the reason for the chromosomal studies, and karyotypes were investigated.
We found that 22 of 18,049 (0.12%) fetuses were diagnosed with Klinefelter syndrome. The incidence of this disorder in male fetuses was 22 of 9,387 (0.23%). Also, 19 of the newborns (86.4%) showed a karyotype of 47,XXY; the other newborns showed karyotypes of 48,XXY,+21; 48,XXY,+12[12]/46,XY[54]; and 47,XXY[6]/45,X[1]/46,XY[95]. The mean age of the mothers was 36.1 years, and 2 women had a past history of a Down syndrome pregnancy. Nine mothers had a normal spontaneous delivery, 9 mothers underwent artificial abortion, and 2 fetuses were spontaneously aborted.
The incidence of Klinefelter syndrome as reported in this study is higher than in previous studies. Further studies with a broader population should be considered to confirm these results.
PMCID: PMC3630347  PMID: 23614065
Karyotype; Klinefelter syndrome; Male infertility
13.  MRI-Guided Intervention for Breast Lesions Using the Freehand Technique in a 3.0-T Closed-Bore MRI Scanner: Feasibility and Initial Results 
Korean Journal of Radiology  2013;14(2):171-178.
To report the feasibility of magnetic resonance imaging (MRI)-guided intervention for diagnosing suspicious breast lesions detectable by MRI only, using the freehand technique with a 3.0-T closed-bore MRI scanner.
Materials and Methods
Five women with 5 consecutive MRI-only breast lesions underwent MRI-guided intervention: 3 underwent MRI-guided needle localization and 2, MRI-guided vacuum-assisted biopsy. The interventions were performed in a 3.0-T closed-bore MRI system using a dedicated phased-array breast coil with the patients in the prone position; the freehand technique was used. Technical success and histopathologic outcome were analyzed.
MRI showed that four lesions were masses (mean size, 11.5 mm; range, 7-18 mm); and 1, a nonmass-like enhancement (maximum diameter, 21 mm). The locations of the lesions with respect to the breast with index cancer were as follows: different quadrant, same breast - 3 cases; same quadrant, same breast - 1 case; and contralateral breast - 1 case. Histopathologic evaluation of the lesions treated with needle localization disclosed perilobular hemangioma, fibrocystic change, and fibroadenomatous change. The lesions treated with vacuum-assisted biopsy demonstrated a radial scar and atypical apocrine hyperplasia. Follow-up MRI after 2-7 months (mean, 4.6 months) confirmed complete lesion removal in all cases.
MRI-guided intervention for breast lesions using the freehand technique with a 3.0-T closed-bore MRI scanner is feasible and accurate for diagnosing MRI-only lesions.
PMCID: PMC3590327  PMID: 23482868
Breast neoplasms; Magnetic resonance imaging; Biopsy; High field; Freehand technique; Needle localization
14.  The Unusual Ultrasound Features of a Breast Cholesterol Granuloma Manifesting as an Intracystic Mass: Case Report and Literature Review 
Korean Journal of Radiology  2013;14(2):179-182.
Cholesterol granuloma of the breast is a rare, benign disease. Here, we present the unique ultrasonographic findings of breast cholesterol granuloma manifesting as an intracystic mass. The findings of this case report may help expand existing knowledge regarding differential diagnosis of intracystic breast masses, which are found on ultrasonographic examination.
PMCID: PMC3590328  PMID: 23482884
Breast; Cholesterol granuloma; Ultrasonography
15.  Non-invasive prenatal diagnosis of fetal trisomy 21 using cell-free fetal DNA in maternal blood 
Since the existence of cell-free fetal DNA (cff-DNA) in maternal circulation was discovered, it has been identified as a promising source of fetal genetic material in the development of reliable methods for non-invasive prenatal diagnosis (NIPD) of fetal trisomy 21 (T21). Currently, a prenatal diagnosis of fetal T21 is achieved through invasive techniques, such as chorionic villus sampling or amniocentesis. However, such invasive diagnostic tests are expensive, require expert technicians, and have a miscarriage risk approximately 1%. Therefore, NIPD using cff-DNA in the detection of fetal T21 is significant in prenatal care. Recently, the application of new techniques using single-molecular counting methods and the development of fetal-specific epigenetic markers has opened up new possibilities in the NIPD of fetal T21 using cff-DNA. These new technologies will facilitate safer, more sensitive and accurate prenatal tests in the near future. In this review, we investigate the recent methods for the NIPD of fetal T21 and discuss their implications in future clinical practice.
PMCID: PMC3784100  PMID: 24327983
Cell-free fetal DNA; Noninvasive prenatal diagnosis; Trisomy 21
16.  Cell-Free Fetal DNA and Cell-Free Total DNA Levels in Spontaneous Abortion with Fetal Chromosomal Aneuploidy 
PLoS ONE  2013;8(2):e56787.
Cell-free fetal DNA and cell-free total DNA in maternal circulation have been proposed as potential markers for noninvasive monitoring of the placental condition during the pregnancy. However, the correlation of and change in cell-free fetal DNA and cell-free total DNA in spontaneous abortion (SA) with fetal chromosomal aneuploidy have not yet been reported. Therefore, we investigated cell-free fetal DNA and cell-free total DNA levels in SA women with fetal chromosomal aneuploidy.
Methodology/Principal Findings
A nested case-control study was conducted with maternal plasma collected from 268 women in their first trimester of pregnancy. Subjects included 41 SA with normal fetal karyotype, 26 SA with fetal chromosomal aneuploidy, and 201 normal controls. The unmethylated PDE9A gene was used to measure the maternal plasma levels of cell-free fetal DNA. The GAPDH gene was used to measure the maternal plasma levels of cell-free total DNA. The diagnostic accuracy was measured using receiver-operating characteristic (ROC) curves. Levels of cell-free fetal DNA and cell-free total DNA were significantly higher in both SA women with normal fetal karyotype and SA women with fetal chromosomal aneuploidy in comparison with the normal controls (P<0.001 in both). The correlation between cell-free fetal DNA and cell-free total DNA levels was stronger in the normal controls (r = 0.843, P<0.001) than in SA women with normal karyotype (r = 0.465, P = 0.002) and SA women with fetal chromosomal aneuploidy (r = 0.412, P = 0.037). The area under the ROC curve for cell-free fetal DNA and cell-free total DNA was 0.898 (95% CI, 0.852–0.945) and 0.939 (95% CI, 0.903–0.975), respectively.
Significantly high levels of cell-free fetal DNA and cell-free total DNA were found in SA women with fetal chromosomal aneuploidy. Our findings suggest that cell-free fetal DNA and cell-free total DNA may be useful biomarkers for the prediction of SA with fetal chromosomal aneuploidy, regardless of fetal gender.
PMCID: PMC3574115  PMID: 23457614
17.  Prosthetic Valve Endocarditis Due to Neisseria skkuensis, a Novel Neisseria Species 
Journal of Clinical Microbiology  2012;50(8):2820-2822.
We describe the first reported case of endocarditis due to Neisseria skkuensis. The organism from the blood cultures taken on admission day was identified initially as unidentified Gram-negative cocci by Vitek2. Finally, it was identified as Neisseria skkuensis by 16 rRNA gene sequence analysis.
PMCID: PMC3421520  PMID: 22675133
18.  Predictive factors affecting cecal intubation failure in colonoscopy trainees 
Successful cecal intubation (SCI) is not only a quality indicator but also an important marker in a colonoscopy trainee’s progress. We conducted this study to determine factors predicting SCI in colonoscopy trainees, and to compare these factors before and after trainees achieve technical competence.
Design of this study was a cross-sectional studies of two time series design for one year at a single center. From March 2011 to February 2012, a total 2,050 subjects who underwent colonoscopy by four first-year gastrointestinal fellows were enrolled at Christian hospital, Wonju, Republic of Korea. Four gastrointestinal fellows have filled out the colonoscopic documentation. Main outcome measurement was predictive factors affecting cecal intubation failure and learning curves.
Colonoscopy was successfully completed to the cecum in 1,720 patients (83.9%). Success rates gradually increased as trainees performed more colonoscopies: the rate of SCI was 62% in the first 50 cases, and grew to 93% by the 250th case. Logistic regression analysis of factors affecting cecal intubation failure showed that female gender, low BMI (BMI < 18.5 kg/m2), poor bowel preparation, and past history of stomach surgery were more often associated with cecal intubation failure, particularly before the trainees achieved technical competence.
Several patient characteristics were identified that may predict difficulty of cecal intubation in colonoscopy trainees. Particularly, low BMI, inadequate bowel cleansing, and previous stomach operation were predictors of cecal intubation failure before the trainees have reached technical competency. The results could be informative so that trainees enhance the success rate regarding better colonoscopy training programs.
PMCID: PMC3560110  PMID: 23331720
19.  Role of MYH9 and APOL1 in African and non-African populations with Lupus Nephritis 
Genes and Immunity  2011;13(3):232-238.
Systemic lupus erythematosus (SLE) is a complex autoimmune disease characterized by autoantibody production and organ damage. Lupus nephritis (LN) is one of the most severe manifestations of SLE. Multiple studies reported associations between renal diseases and variants in the non-muscle myosin heavy chain 9 (MYH9) and the neighboring apolipoprotein L 1 (APOL1) genes. We evaluated 167 variants spanning MYH9 for association with LN in a multiethnic sample. The two previously identified risk variants in APOL1 were also tested for association with LN in European-Americans (EAs) (N = 579) and African-Americans (AAs) (N = 407). Multiple peaks of association exceeding a Bonferroni corrected p-value of p < 2.03 × 10−3 were observed between LN and MYH9 in EAs (N=4620), with the most pronounced association at rs2157257 (p = 4.7 × 10−4; odds ratio [OR]=1.205). A modest effect with MYH9 was also detected in Gullah (rs8136069, p = 0.0019, OR = 2.304). No association between LN and MYH9 was found in AAs, Asians, Amerindians or Hispanics. This study provides the first investigation of MYH9 in LN in non-Africans and of APOL1 in LN in any population and presents novel insight into the potential role of MYH9 in LN in EAs.
PMCID: PMC3330160  PMID: 22189356
MYH9; APOL1; lupus nephritis; systemic lupus erythematosus; multiethnic association study
20.  Invasive Cribriform Carcinoma Arising in Malignant Phyllodes Tumor of Breast: A Case Report 
Korean Journal of Pathology  2012;46(2):205-209.
Phyllodes tumor is an uncommon fibroepithelial neoplasm of the breast. And it is characterized by expanded stroma with increased cellularity and elongated epithelium-lined clefts. Mammary carcinomas within phyllodes tumors have been rarely reported. To date, however, no reports have described the invasive cribriform carcinoma arising in malignant phyllodes tumor. Here, we report a 62-year-old woman who presented with a large breast mass. Microscopically, the mass was a typical malignant phyllodes tumor showing well developed leaf-like architecture and stromal overgrowth with high cellularity and nuclear pleomorphism. In a portion of the tumor, however, the epithelial component showed a cribriform pattern of proliferation in the absence of myoepithelial cells, suggestive of the invasive cribriform carcinoma. To our knowledge, this is rare and it is difficult to make a differential diagnosis of it. Here, we report our case with a review of literatures.
PMCID: PMC3479779  PMID: 23110003
Invasive carcinoma; Phyllodes tumor; Breast; Cribriform
21.  Liquid-Based Cytology of Villoglandular Adenocarcinoma of the Cervix: A Report of 3 Cases 
Korean Journal of Pathology  2012;46(2):215-220.
Villoglandular adenocarcinoma (VGA) is a rare subtype of cervical adenocarcinoma with a more favorable prognosis compared to conventional adenocarcinomas. Although the tumors are usually recognized on colposcopic examination due to the mainly exophytic growth pattern, they may be underdiagnosed as benign lesions by cytology because of their minimal cytologic atypia. We report the liquid-based cytology (LBC) findings of three histologically confirmed VGAs which we have recently identified. They were characterized by hypercellular smears on low-power examination with smooth-bordered three-dimensional papillary fragments. The nuclei were relatively uniform with irregular nuclear membranes. Nucleoli were small but distinct and macronucleoli were also seen. The abnormal architectural patterns such as papillary structures and nuclear overlapping and nuclear hyperchromasia are important clues to the diagnosis of VGA. In addition, nuclear membrane irregularity and prominent nucleoli can be recognized on LBC specimens, further facilitating its diagnosis.
PMCID: PMC3479784  PMID: 23110005
Villoglandular adenocarcinoma; Uterine cervical neoplasms; Liquid-based cytology
22.  A Case of Non-Hodgkin's Lymphoma in Patient with Coombs' Negative Hemolytic Anemia and Idiopathic Thrombocytopenic Purpura 
Coombs' negative autoimmune hemolytic anemia (AIHA) is a rare disease which shares similar clinical and hematological features with Coombs' positive AIHA, but its exact frequency remains unknown. There have been few reports of idiopathic thrombocytopenic purpura (ITP) and Coombs' negative AIHA associated with other lymphoproliferative disorders (LPDs). Since there is a well known association between LPDs and autoimmune phenomena, it is important to investigate the possibility of an underlying malignancy. We report a case of ITP and Coombs' negative AIHA associated with diffuse large B-cell lymphoma.
PMCID: PMC3322204  PMID: 22500164
Lymphoma; Hemolytic anemia; Coombs' test; Idiopathic thrombocytopenic purpura
23.  Non-invasive prenatal detection of achondroplasia using circulating fetal DNA in maternal plasma 
To perform a reliable non-invasive detection of the fetal achondroplasia using maternal plasma.
We developed a quantitative fluorescent-polymerase chain reaction (QF-PCR) method suitable for detection of the FGFR3 mutation (G1138A) causing achondroplasia. This method was applied in a non-invasive detection of the fetal achondroplasia using circulating fetal-DNA (cf-DNA) in maternal plasma. Maternal plasmas were obtained at 27 weeks of gestational age from women carrying an achondroplasia fetus or a normal fetus.
Two percent or less achondroplasia DNA was reliably detected by QF-PCR. In a woman carrying a normal fetus, analysis of cf-DNA showed only one peak of the wild-type G allele. In a woman expected an achondroplasia fetus, analysis of cf-DNA showed the two peaks of wild-type G allele and mutant-type A allele and accurately detected the fetal achondroplasia.
The non-invasive method using maternal plasma and QF-PCR may be useful for diagnosis of the fetal achondroplasia.
PMCID: PMC3059531  PMID: 20963478
Achondroplasia; Non-invasive prenatal diagnosis; Maternal plasma; QF-PCR
24.  Association between genetic polymorphisms in androgen receptor gene and the risk of preeclampsia in Korean women 
To investigate associations between the androgen receptor (AR) polymorphisms as CAG repeats, GGC repeats and c.211G>A polymorphism and the risk of preeclampsia.
The AR polymorphisms were experienced in 184 preeclamptic patients and 190 normal pregnancies and analyzed by multiple logistic regression.
Women with GGC repeats>16 were more frequently observed in preeclampsia, compared to those with GGC repeats≤16 [adjOR (95% CI): 3.64 (1.71–6.23)]. However, no significant differences were observed between the two groups with respect to CAG repeats. The genotypic and allelic frequencies of c.211G>A variant were significantly higher in cases than in controls (P < 0.05 for both). In the combined distribution of these polymorphisms, the highest risk of preeclampsia was found among women with the haplotype as CAG > 20/GA/GGC>16 [adjOR (95% CI): 4.26 (1.92–12.23)].
Our findings suggest that longer GGC repeats and c.211G>A variant in the AR gene are associated with increased susceptibility to the risk of preeclampsia.
PMCID: PMC3045487  PMID: 20922474
Androgen receptor; CAG repeats; GGC repeats; c.211G>A polymorphism; Preeclampsia
25.  Diffusion-Weighted Imaging of a Prostate Cancer Xenograft Model Seen on a 7 Tesla Animal MR Scanner: Comparison of ADC Values and Pathologic Findings 
Korean Journal of Radiology  2011;13(1):82-89.
To assess the relationship between apparent diffusion coefficient (ADC) values on diffusion-weighted magnetic resonance (MR) imaging and pathologic measures of a tumor using a prostate cancer xenograft model.
Materials and Methods
Eighteen athymic nude mice with 36 PC-3-induced tumors were sacrificed to obtain specimens immediately after MR imaging in order to compare the findings on MR images with those seen on pathological specimens. Using a high-field small-animal MR scanner, T1- and T2-weighted imaging and DW MR imaging was performed. Tumors were then processed for Hematoxylin and Eosin staining to evaluate tumor cellularity, intratumoral necrosis and immunostaining using antibodies directed against CD31 and vascular endothelial growth factor (VEGF) to determine the levels of microvessel density (MVD). Mean ADC values that were measured on the solid portion within each tumor were compared with tumor volume, cellularity, degree of necrosis, VEGF expression, and MVD in the corresponding section of the pathological specimen.
Mean ADC values of the solid portion within the PC-3-induced high-grade tumors were significantly correlated with the degree of intratumoral necrosis (r = 0.63, p < 0.0001) and MVD (r = -0.44, p = 0.008) on pathologic slides. The ADC values were not significantly correlated with tumor cellularity, VEGF expression, or tumor volume in high-grade prostate cancer tissues.
In the xenografted prostate cancer model, the ADC values of the solid portion of the tumors are significantly correlated with tumor necrosis and MVD of the pathologic specimens. The ADC values may be utilized as surrogate markers for the noninvasive assessment of tumor necrosis and MVD in high-grade prostate cancer.
PMCID: PMC3253407  PMID: 22247640
PC3; Prostate; Diffusion weighted imaging; MR; Necrosis; MVD

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