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1.  Validation of a New Food Frequency Questionnaire for Assessment of Calcium and Vitamin D Intake in Korean Women 
Journal of Bone Metabolism  2013;20(2):67-74.
Validated simple calcium questionnaires are available to assess the intake of calcium and vitamin D in western countries, but they are not appropriate for Koreans since dairy products are not the major source of calcium and vitamin D in Korea. Thus, the objective of the present study was to develop and validate a simple and easy food frequency questionnaire (FFQ) of calcium and vitamin D for Korean.
Two hundred and fifty-six women were asked to complete the validated FFQ used by the Korean National Health and Nutrition Examination Survey (KNHANES) and a newly developed FFQ, the Korean Calcium Assessment Tool (KCAT), which contain the 7 food groups with 24 categories of 45 food items that are consumed frequently by Koreans.
Calcium intake was not significantly different between the two methods; Pearson's correlation coefficient of 0.98 indicated a positive correlation, and Cohen's kappa coefficient of 0.78 indicated the subjects were correctly classified. Bland-Altman plot also showed that the mean differences of the calcium intake as assessed by the two methods were in high agreement. However, the vitamin D intake assessed by KCAT was significantly higher than that assessed by the FFQ used in KNHANES. The vitamin D intakes as assessed by the two methods were positively correlated but the two methods were in moderate agreement.
The results suggested that the newly developed KCAT was a valid tool for assessing the calcium intake in Korean women, but it might overestimate the vitamin D intake.
PMCID: PMC3910312  PMID: 24524060
Calcium; Diet surveys; Korean women; Vitamin D; Questionnaires
2.  Activation of a plant nucleotide binding-leucine rich repeat disease resistance protein by a modified self protein 
Cellular Microbiology  2012;14(7):1071-1084.
Nucleotide binding-leucine rich repeat (NB-LRR) proteins function as intracellular receptors for the detection of pathogens in both plants and animals. Despite their central role in innate immunity, the molecular mechanisms that govern NB-LRR activation are poorly understood. The Arabidopsis NB-LRR protein RPS5 detects the presence of the Pseudomonas syringae effector protein AvrPphB by monitoring the status of the Arabidopsis protein kinase PBS1. AvrPphB is a cysteine protease that targets PBS1 for cleavage at a single site within the activation loop of PBS1. Using a transient expression system in the plant Nicotiana benthamiana and stable transgenic Arabidopsis plants we found that both PBS1 cleavage products are required to activate RPS5 and can do so in the absence of AvrPphB. We also found, however, that the requirement for cleavage of PBS1 could be bypassed simply by inserting five amino acids at the PBS1 cleavage site, which is located at the apex of the activation loop of PBS1. Activation of RPS5 did not require PBS1kinase function, thus RPS5 appears to sense a subtle conformational change in PBS1, rather than cleavage. This finding suggests that NB-LRR proteins may function as fine-tuned sensors of alterations in the structures of effector targets.
PMCID: PMC3371279  PMID: 22372664
3.  The Pleiohomeotic Functions as a Negative Regulator of Drosophila even-skipped Gene during Embryogenesis 
Molecules and Cells  2011;32(6):549-554.
Polycomb group (PcG) proteins maintain the spatial expression patterns of genes that are involved in cell-fate specification along the anterior-posterior (A/P) axis. This repression requires cis-acting silencers, which are called PcG response elements (PREs). One of the PcG proteins, Pleiohomeotic (Pho), which has a zinc finger DNA binding protein, plays a critical role in recruiting other PcG proteins to bind to PREs. In this study, we characterized the effects of a pho mutation on embryonic segmentation. pho maternal mutant embryos showed various segmental defects including pair-rule gene mutant patterns. Our results indicated that engrailed and even-skipped genes were misexpressed in pho mutant embryos, which caused embryonic segment defects.
PMCID: PMC3887676  PMID: 22080372
eve; Drosophila melanogaster; GAGA; pleiohomeotic; Polycomb group genes; PRE; segmentation genes
4.  The Arabidopsis Resistance-Like Gene SNC1 Is Activated by Mutations in SRFR1 and Contributes to Resistance to the Bacterial Effector AvrRps4 
PLoS Pathogens  2010;6(11):e1001172.
The SUPPRESSOR OF rps4-RLD1 (SRFR1) gene was identified based on enhanced AvrRps4-triggered resistance in the naturally susceptible Arabidopsis accession RLD. No other phenotypic effects were recorded, and the extent of SRFR1 involvement in regulating effector-triggered immunity was unknown. Here we show that mutations in SRFR1 in the accession Columbia-0 (Col-0) lead to severe stunting and constitutive expression of the defense gene PR1. These phenotypes were temperature-dependent. A cross between srfr1-1 (RLD background) and srfr1-4 (Col-0) showed that stunting was caused by a recessive locus in Col-0. Mapping and targeted crosses identified the Col-0-specific resistance gene SNC1 as the locus that causes stunting. SRFR1 was proposed to function as a transcriptional repressor, and SNC1 is indeed overexpressed in srfr1-4. Interestingly, co-regulated genes in the SNC1 cluster are also upregulated in the srfr1-4 snc1-11 double mutant, indicating that the overexpression of SNC1 is not a secondary effect of constitutive defense activation. In addition, a Col-0 RPS4 mutant showed full susceptibility to bacteria expressing avrRps4 at 24°C but not at 22°C, while RLD susceptibility was not temperature-dependent. The rps4-2 snc1-11 double mutant showed increased, but not full, susceptibility at 22°C, indicating that additional cross-talk between resistance pathways may exist. Intriguingly, when transiently expressed in Nicotiana benthamiana, SRFR1, RPS4 and SNC1 are in a common protein complex in a cytoplasmic microsomal compartment. Our results highlight SRFR1 as a convergence point in at least a subset of TIR-NBS-LRR protein-mediated immunity in Arabidopsis. Based on the cross-talk evident from our results, they also suggest that reports of constitutive resistance phenotypes in Col-0 need to consider the possible involvement of SNC1.
Author Summary
Plants, like humans, have an immune system to defend against disease. This immune system seeks out the presence of disease-causing microbes and other invaders by detecting non-plant molecules and proteins. Plants rely on this surveillance to activate an antimicrobial response of appropriate strength at the right time; as with humans, an overactive immune system can be harmful to plants. We study how plants achieve an appropriate balance, using genetics and the interaction between the reference plant Arabidopsis thaliana and the bacterial plant pathogen Pseudomonas syringae. So-called plant resistance proteins are important activators of immunity that directly or indirectly intercept foreign proteins deployed by pathogens. Resistance proteins are generally thought to be highly specific detectors that only respond to a single pathogen protein. However, while working with a negative regulator of plant immunity called SRFR1, we discovered a surprising level of cross-talk between different resistance proteins that becomes evident only under certain environmental conditions such as low temperature. We also show that SRFR1 and these resistance proteins bind to each other, possibly explaining the observed cross-talk. Our work thus highlights linkages between resistance pathways and provides insight into the molecular architecture of the plant innate immune response.
PMCID: PMC2973837  PMID: 21079790
5.  Regulation of defense gene expression by Arabidopsis SRFR1 
Plant Signaling & Behavior  2009;4(2):149-150.
Reduced growth and viability is a common phenotype of plants with constitutively activated pathogen defenses. One branch of the plant innate immunity system, effector-triggered immunity, is especially potent and requires tight control to enable normal plant development. While some facets of this control that directly regulate resistance protein abundance or activity have been documented, general control of effector-triggered signaling sensitivity is poorly understood. We recently identified SUPPRESSOR OF rps4-RLD 1 (SRFR1), a novel negative regulator of avrRps4-triggered immunity. Mutations in SRFR1 were previously shown not to induce constitutive high expression of the defense gene PR1, and to be fully susceptible to the virulent Pseudomonas syringae pv. tomato strain DC3000. SRFR1 encodes a tetratricopeptide repeat-containing protein with weak similarity to transcriptional repressors in other organisms. By transient expression in Nicotiana benthamiana, SRFR1 was localized to the nucleus. Here we investigate more carefully whether expression of defense genes is misregulated in srfr1 mutant plants. Consistent with the hypothesized function of SRFR1 as a negative transcriptional regulator, we find that mRNA levels of several defense genes are upregulated in srfr1 mutants.
PMCID: PMC2637506  PMID: 19649196
Arabidopsis thaliana; Pseudomonas syringae; disease resistance; avrRps4; RPS4; transcriptional repressor
6.  EC-18, a Synthetic Monoacetyldiacylglyceride, Inhibits Hematogenous Metastasis of KIGB-5 Biliary Cancer Cell in Hamster Model 
Journal of Korean Medical Science  2009;24(3):474-480.
EC-18 (monoacetyldiacylglyceride) stimulates T cell production of IL-2, IL-4, IL-12, IFN-γ, and GM-CSF in vitro. To study the effects of these cytokines stimulated by EC-18 on cancer cells, we applied hamster biliary cancer model, a difficult cancer to treat. Cancer (KIGB-5) cells were given intravenously to produce hematogenous metastatic lung lesions which were treated with EC-18 at 10, 25, and 50 mg/kg/day respectively. The fourth group was untreated control. At 4th, 8th, and 12th week the lungs were examined. EC-18 treated groups showed only a few microscopic lung lesions and no evidence of metastatic lesion with highest dose whereas widespread gross lung lesions were observed in untreated control. To investigate whether the anti-tumor effect of EC-18 is associated with suppression of tumor cell Toll-like receptor 4 (TLR-4) expression in addition to stimulation of the immune cells, KIGB-5 cells were exposed to LPS with or without EC-18. TLR-4 mRNA and protein expression, measured by reverse transcriptase PCR (RT-PCR), real-time quantitative PCR and western blot analysis, showed suppression of TLR-4 expression in KIGB-5 cells treated with EC-18 compared with control. In conclusion, EC-18 has a significant anti-tumor effect in this experimental model of biliary cancer suggesting potential for clinical application to this difficult cancer.
PMCID: PMC2698195  PMID: 19543512
EC-18; Anti-Tumor Effect; TLR-4; Biliary Cancer
7.  Cotransplanted Bone Marrow Derived Mesenchymal Stem Cells (MSC) Enhanced Engraftment of Hematopoietic Stem Cells in a MSC-dose Dependent Manner in NOD/SCID Mice 
Journal of Korean Medical Science  2006;21(6):1000-1004.
Transplantation of marrow-derived mesenchymal stem cells (MSCs), expanded by culture in addition to whole bone marrow, has been shown to enhance engraftment of human hematopoietic stem cells (HSCs). Our hypothesis was that there might be an optimum ratio range that could enhance engraftment. We examined the percent donor chimerism according to the ratio of HSCs to MSCs in non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice. We tested a series of ratios of co-transplanted CD34+-selected bone marrow cells, and marrow-derived MSCs into sublethally irradiated NOD/SCID mice. In all experiments, 1×105 bone marrow derived human CD34+ cells were administered to each mouse and human MSCs from different donors were infused concomitantly. We repeated the procedure three times and evaluated engraftment with flow cytometry four weeks after each transplantation. Serial ratios of HSCs to MSCs were 1:0, 1:1, 1:2 and 1:4, in the first experiment, 1:0, 1:1, 1:2, 1:4 and 1:8 in the second and 1:0, 1:1, 1:4, 1:8 and 1:16 in the third. Cotransplantation of HSCs and MSCs enhanced engraftment as the dose of MSCs increased. Our results suggest that the optimal ratio of HSCs and MSCs for cotransplantation might be in the range of 1:8-1:16; whereas, an excessive dose of MSCs might decrease engraftment efficiency.
PMCID: PMC2721918  PMID: 17179676
Hematopoietic Stem Cells; Mesenchymal Stem Cells; Transplantation; Mice, SCID; Engraftment
8.  Prognostic Factors in Non-Hodgkin's Lymphoma Patients Treated by Autologous Stem Cell Transplantation: A Single Center Experience 
Autologous stem cell transplantation (ASCT) is increasingly used in patients with non-Hodgkin's lymphoma (NHL). Various clinical parameters-were evaluated to obtain significant predictors of the outcome following ASCT in patients with NHL.
Materials and Methods
Between April 1994 and December 2003, ASCT was performed on 80 patients with NHL at the Asan Medical Center.
Patients had various histological subtypes and disease status. The two year progression free survival (PFS) and overall survival for all patients were 34 and 31%, respectively. A univariate analysis showed the performance status, stage, modified extranodal involvement category, International Prognostic Index (IPI) at mobilization, disease status at mobilization, and history of radiation prior to mobilization as significant predictors of the outcome following ASCT. Four risk groups, with different 2 year PFS, were identified by the age adjusted IPI at mobilization (mAAIPI): low risk 44%; low intermediate risk 40%; high intermediate risk 19%; and high risk 0% (p=.0003). A multivariate analysis revealed 3 significant factors for the PFS: disease status, prior RT and mAAIPI.
The mAAIPI was found to be an independent predictor of the outcome of NHL patients undergoing ASCT. This powerful prognostic tool should be used to evaluate potential candidates for ASCT.
PMCID: PMC2785926  PMID: 19956530
Non-Hodgkin's lymphoma; Autologous peripheral blood stem cell transplantation; Prognosis; Hematopoietic stem cell mobilization
9.  High-Dose Chemotherapy of Cyclophosphamide, Thiotepa and Carboplatin (CTCb) followed by Autologous Stem-Cell Transplantation as a Consolidation for Breast Cancer Patients with 10 or more Positive Lymph Nodes: a 5-Year follow-Up Results 
The benefit of consolidation high-dose chemotherapy (HDC) for high-risk primary breast cancer is controversial. We evaluated the efficacy and safety of consolidation HDC with cyclophosphamide, thiotepa and carboplatin (CTCb) followed by autologous stem-cell transplantation (ASCT) in resected breast cancer patients with 10 or more positive lymph nodes.
Materials and Methods
Between December 1994 and April 2000, 22 patients were enrolled. All patients received 2 to 6 cycles of adjuvant chemotherapy after surgery for breast cancer. The HDC regimen consisted of cyclophosphamide 1,500 mg/m2/day, thiotepa 125 mg/m2/day and carboplatin 200 mg/m2/day intravenous for 4 consecutive days.
With a median follow-up of 58 months, 11 patients recurred and died. The median disease-free survival (DFS) and median overall survival (OS) were 49 and 69 months, respectively. The 5-year DFS and OS rates were 50% and 58%, respectively. The 12 patients with 10 to 18 involved nodes had better 5-year DFS (67%) and OS (75%) than 10 patients with more than 18 involved nodes (30% and 38%, respectively). The most common grade 3 or 4 nonhematologic toxicity was diarrhea, which occurred in 5 patients (23%). No treatment-related death was observed.
Consolidation HDC with CTCb followed by ASCT for resected breast cancer with more than 10 positive nodes had an acceptable toxicity but does not show promising survival.
PMCID: PMC2785413  PMID: 19956494
Breast Neoplasms; Peripheral blood stem cell transplantation; Cyclophosphamide; Thiotepa; Carboplatin; Consolidation
10.  High-Dose Chemotherapy of Cyclophosphamide, Thiotepa, and Carboplatin (CTCb) Followed by Autologous Stem-Cell Transplantation for Metastatic Breast Cancer Patients: A 6-Year Follow-Up Result 
The benefit of high-dose chemotherapy (HDC) for metastatic breast cancer (MBC) is controversial. We evaluated the efficacy and safety of HDC with cyclophosphamide, thiotepa, and carboplatin (CTCb) followed by autologous stem-cell transplantation (ASCT) for MBC patients.
Materials and Methods
From September 1994 to December 1999, 23 MBC patients were enrolled. All the patients received 2 to 10 cycles of induction chemotherapy. Before transplantation, 12 patients were in complete response (CR), nine were in partial response (PR), and two had progressive disease (PD). The HDC regimen consisted of cyclophosphamide 1,500 mg/m2/day, thiotepa 125 mg/m2/day and carboplatin 200 mg/m2/day intravenously for 4 consecutive days.
After ASCT, 13 patients (56%) had a CR, five (22%) had a PR, three (13%) had no change, while two (9%) showed a PD. Seventeen patients relapsed or progressed during the median follow-up of 78 months. The median progression-free survival (PFS) time was 11 months and the median overall survival (OS) time was 23 months. The 5-year PFS and OS rates were 22% and 25%, respectively. On the multivariate analyses, less than 4 involved lymph nodes was predictive of a better PFS and OS.
HDC with CTCb for MBC has acceptable toxicity; however, this treatment does not show a survival benefit.
PMCID: PMC2785419  PMID: 19956506
Metastatic breast neoplasms; High-dose chemotherapy; Cyclophosphamide; Thiotepa; Carboplatin
11.  Activity of Green Tea Polyphenol Epigallocatechin-3-gallate Against Ovarian Carcinoma Cell Lines 
A constituent of green tea, (-)-epigallocatechin-3-gallate (EGCG), is known to possess anti-cancer properties. In this study, the time-course of the anticancer effects of EGCG on human ovarian cancer cells were investigated to provide insights into the molecular-level understanding of the growth suppression mechanism involved in EGCG-mediated apoptosis and cell cycle arrest.
Materials and Methods
Three human ovarian cancer cell lines (p53 negative, SKOV-3 cells; mutant type p53, OVCAR-3 cells; and wild type p53, PA-1 cells) were used. The effect of EGCG treatment was studied via a cell count assay, cell cycle analysis, FACS, Western blot and macroarray assay.
EGCG exerts a significant role in suppressing ovarian cancer cell growth, showed dose dependent growth inhibitory effects in each cell line and induced apoptosis and cell cycle arrest. The cell cycle was arrested at the G1 phase by EGCG in SKOV-3 and OVCAR-3 cells.
In contrast, the cell cycle was arrested in the G1/S phase in PA-1 cells. EGCG differentially regulated the expression of genes and proteins (Bax, p21, Retinoblastoma, cyclin D1, CDK4 and Bcl-XL) more than 2 fold, showing a possible gene regulatory role for EGCG. The continual expression in p21WAF1 suggests that EGCG acts in the same way with p53 proteins to facilitate apoptosis after EGCG treatment. Bax, PCNA and Bcl-X are also important in EGCG-mediated apoptosis. In contrast, CDK4 and Rb are not important in ovarian cancer cell growth inhibition.
EGCG can inhibit ovarian cancer cell growth through the induction of apoptosis and cell cycle arrest, as well as in the regulation of cell cycle related proteins. Therefore, EGCG-mediated apoptosis could be applied to an advanced strategy in the development of a potential drug against ovarian cancer.
PMCID: PMC2843866  PMID: 20368822
(-)-epigallocatechin-3-gallate (EGCG); Ovarian Cancer; Apoptosis; Cell Cycle
12.  Active immunization using dendritic cells mixed with tumor cells inhibits the growth of lymphomas. 
Journal of Korean Medical Science  2003;18(3):372-380.
Dendritic cells (DCs) are potent antigen-presenting cells for the induction and activation of cytotoxic T lymphocytes. We tested whether bone marrow-derived DCs are capable of inducing protective immunity against a murine lymphoma (A20). DCs were grown from tumor-bearing BALB/c mice by culturing bone marrow cells. BALB/c mice were injected (sc) with A20 cells on day 0. Intraperitoneal immunization with DCs mixed with lethally irradiated A20 cells were started when the tumor reached ca. 4-5 mm in diameter (Group A) or on day -7 (Group B). Booster immunizations were given every 3-4 days for four weeks. By 31 days in group A, there was a significant reduction in tumor growth in the mice immunized with DCs mixed with irradiated A20 cells as compared with the control groups (p=0.016). In group B, tumor growth was completely inhibited and there was no tumor growth following extended observations after completion of immunization. Thus, DCs mixed with irradiated tumor cells can induce an antitumor effect. This provides a rationale for the use of DCs mixed with irradiated tumor cells in immunotherapy for minimal residual disease of lymphomas.
PMCID: PMC3055039  PMID: 12808324
13.  A case of treatment-related myelodysplastic syndrome and acute myelogenous leukemia following high-dose chemotherapy with autologous stem cell transplantation for non-Hodgkin's lymphoma. 
Journal of Korean Medical Science  2002;17(4):555-559.
Treatment-related myelodysplastic syndrome (t-MDS) and acute myelogenous leukemia (t-AML) are now well established as complications of cytotoxic chemotherapy. We experienced a 28-yr-old female patient who developed t-MDS/t-AML with characteristic chromosomal abnormalities including 11q23 chromosomal rearrangement following high-dose chemotherapy with autologous stem cell transplantation (ASCT) for non-Hodgkin's lymphoma. The patient was admitted with bulky abdominal masses of B cell lineage non-Hodgkin's lymphoma. After 2 cycles of systemic chemotherapy of the Vanderbilt regimen, the patient underwent ASCT with high dose chemotherapy of the BEAC regimen. She also received radiation of 48 Gy for the residual periportal lymphadenopathy. The initial cytogenetic analysis of the infused mononuclear cells revealed a normal karyotype. Twenty two months after the ASCT, pancytopenia was noted and her bone marrow aspirate showed dysplastic hemopoiesis with myeloblasts up to 12% of nonerythroid nucleated cells. The patient was diagnosed as t-MDS (refractory anemia with an excess of blasts). Cytogenetic analysis showed complex chromosomal abnormalities including 11q23 rearrangement, which is frequently found in topoisomerase II inhibitor-related hematologic malignancies. Four months later, it was noted that the t-MDS had evolved into an overt t-AML. Cytogenetic analysis showed an evolving pattern with more complex abnormalities. The patient was treated with combination chemotherapy, but her leukemic cells were resistant to the therapy.
PMCID: PMC3054920  PMID: 12172056
14.  Double Autologous Stem Cell Transplantation for Multiple Myeloma: A Korean Single Center Study 
Although high dose chemotherapy coupled with an autologous stem cell transplantation (ASCT) is widely accepted as effective therapy for multiple myeloma (MM), few reports are available in Korea, especially in the area of double ASCT. We present the results of an institutional retrospective study of 12 patients with MM treated by double ASCT.
Eligible patients received induction therapy using vincristine, adriamycin, dexamethasone (VAD), and mobilization was performed using cyclophosphamide plus lenograstim. High-dose melphalan (total 200 mg/m2) was used to condition the ASCT.
The median interval from diagnosis to ASCT was 6 months (range, 1.8-15.3 months). The median interval between the 1st and 2nd ASCT was 4.4 months (range 2.1-48.7 months). The median follow up was 18.3 months (range 8.1-50.5 months) for the nine surviving patients. No therapy-related mortality occurred. Following induction chemotherapy, two patients experienced CR. Following double ASCT, eight patients experienced CR. The 5 year OS was 59%. The median duration of event free survival was 2.13 years (95% CI, 0.84-3.42).
Although the results of study did not demonstrate the advantage of double ASCT, this is the first report to outline the outcome of double ASCT for Korean MM patients.
PMCID: PMC3891159  PMID: 16295783
Multiple myeloma; Autologous; Stem cell transplantation

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