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Articles by D. S Lee
Total Records ( 6 ) for D. S Lee
  I. S Song , S. U Kim , N. S Oh , J Kim , D. Y Yu , S. M Huang , J. M Kim , D. S Lee and N. S. Kim
 

Reactive oxygen species (ROS) have been implicated in tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) resistance of many cancers. We evaluated the role of peroxiredoxin (Prx) I in TRAIL resistance governed by coupling of nicotinamide adenosine dinucleotide phosphate oxidase (Nox)-derived ROS signaling with the p38 mitogen-activated protein kinase (MAPK)/caspase-signaling cascade in liver cancer cells. Upregulated Prx I expression was found in neoplastic regions of human patient liver, and Prx I knockdown resulted in accelerated TRAIL-induced cell death in SK-Hep-1 human hepatoma cells. The TRAIL cytotoxicity by Prx I knockdown was dependent on activation of caspase-8/3 cascades, which was ablated by addition of inhibitors for p38 MAPK, ROS or Nox, suggesting the association with Nox-driven redox signaling. Furthermore, we found that Nox4 was constitutively expressed in both SK-Hep-1 cells and tumor regions of patient livers, knockdown of Nox4 expression could alleviate ROS generation and TRAIL-mediated cytotoxicity. In accordance with previous findings, increased activation of both p38 MAPK and caspase cascades by Prx I knockdown was inhibited by either Nox4 knockdown or SB203580 addition. Collectively, these data suggest that Prx I functions to block propagation of Nox-derived ROS signaling to the p38 MAPK/caspase/cell death cascade during TRAIL treatment and also provides a molecular mechanism by which Prx I contributes to TRAIL resistance in liver cancers.

  D. S Lee , P Gona , R. S Vasan , M. G Larson , E. J Benjamin , T. J Wang , J. V Tu and D. Levy
 

Background— The contributions of risk factors and disease pathogenesis to heart failure with preserved ejection fraction (HFPEF) versus heart failure with reduced ejection fraction (HFREF) have not been fully explored.

Methods and Results— We examined clinical characteristics and risk factors at time of heart failure onset and long-term survival in Framingham Heart Study participants according to left ventricular ejection fraction ≤45% (n=314; 59%) versus >45% (n=220; 41%) and hierarchical causal classification. Heart failure was attributed to coronary heart disease in 278 participants (52%), valvular heart disease in 42 (8%), hypertension in 140 (26%), or other/unknown causes in 74 (14%). Multivariable predictors of HFPEF (versus HFREF) included elevated systolic blood pressure (odds ratio [OR]=1.13 per 10 mm Hg; 95% confidence interval [CI], 1.04 to 1.22), atrial fibrillation (OR=4.23; 95% CI, 2.38 to 7.52), and female sex (OR=2.29; 95% CI, 1.35 to 3.90). Conversely, prior myocardial infarction (OR=0.32; 95% CI, 0.19 to 0.53) and left bundle-branch block QRS morphology (OR=0.21; 95% CI, 0.10 to 0.46) reduced the odds of HFPEF. Long-term prognosis was grim, with a median survival of 2.1 years (5-year mortality rate, 74%), and was equally poor in men and women with HFREF or HFPEF.

Conclusions— Among community patients with new-onset heart failure, there are differences in causes and time-of-onset clinical characteristics between those with HFPEF versus HFREF. In people with HFREF, mortality is increased when coronary heart disease is the underlying cause. These findings suggest that heart failure with reduced left ventricular systolic function and heart failure with preserved left ventricular systolic function are partially distinct entities, with potentially different approaches to early detection and prevention.

  M. S Kim , C. S Lee , J Hur , H. J Cho , S. I Jun , T. Y Kim , S. W Lee , J. W Suh , K. W Park , H. Y Lee , H. J Kang , D. S Lee , G. Y Koh , H Nakagami , R Morishita , Y. B Park and H. S. Kim
 

Background— The low engraftment rate of stem/progenitor cells infused via the intracoronary route to the ischemic myocardium is one of the most important factors limiting the efficacy of cell therapy. We investigated the concept of priming peripheral blood stem cells enriched by granulocyte colony-stimulating factor mobilization and apheresis (mobPBSCs) with angiopoietin-1 (Ang1), to enhance the engraftment into the ischemic tissue and neovasculogenic potential.

Methods and Results— The expression of Tie2, the Ang1 receptor, was significantly higher in mobPBSCs than naïve peripheral blood mononuclear cells (19.2±3.0% versus 1.2±0.8% versus 1.2±0.2%; P<0.001 for mobPBSCs from acute myocardial infarction (AMI) patients with granulocyte colony-stimulating factor treatment for 3 days versus peripheral blood mononuclear cells from AMI patients versus peripheral blood mononuclear cells from stable angina patients). After 4 hours of cartilage oligomeric matrix protein (COMP)-Ang1 stimulation, mobPBSCs committed to the endothelial lineage with the induction of CD31 and VE-cadherin expression, mediated by Tie2/Ets-1 pathway. Priming of mobPBSCs with COMP-Ang1 induced the expression of 4β1 and 5β1 integrins, which are also Ets-1 downstream molecules, leading to enhanced adhesion to endothelial cells or fibronectin. In a rabbit ear ischemia/reperfusion model, priming of mobPBSCs with COMP-Ang1 improved first-pass engraftment to the distal vascular bed after intraarterial delivery. In a murine ischemic hind-limb model, intravascular delivery of primed mobPBSCs enhanced both engraftment and neovascularization.

Conclusions— The short-term priming with COMP-Ang1 may be a feasible and promising option to activate mobPBSCs by enhancing differentiation and adhesiveness and to improve the efficacy of cell therapy for ischemic diseases.

  D. S Lee , N Ghosh , J. S Floras , G. E Newton , P. C Austin , X Wang , P. P Liu , T. A Stukel and J. V. Tu
 

Background— Higher blood pressure in acute heart failure has been associated with improved survival; however, the relationship between blood pressure and survival in stabilized patients at hospital discharge has not been established.

Methods and Results— In 7448 patients with heart failure (75.2±11.5 years; 49.9% men) discharged from the hospital in Ontario, Canada, we examined the association of systolic blood pressure (SBP) and diastolic blood pressure with long-term survival. Parametric survival analysis was performed, and survival time ratios were determined according to discharge blood pressure group. A total of 25 427 person-years of follow-up were examined. In those with left ventricular ejection fraction ≤40%, median survival was decreased by 17% (survival time ratio, 0.83; 95% CI, 0.71 to 0.98; P=0.029) when discharge SBP was 100 to 119 mm Hg and decreased by 23% (survival time ratio, 0.77; 95% CI, 0.62 to 0.97; P=0.024) when discharge SBP was <100 mm Hg, compared with those in the reference range of 120 to 139 mm Hg. Survival time ratios were 0.75 (95% CI, 0.60 to 0.92; P=0.007) and 0.75 (95% CI, 0.53 to 1.07; P=0.12) when discharge SBPs were 140 to 159 and ≥160 mm Hg, respectively. In those with left ventricular ejection fraction >40%, survival time ratios were 0.69 (95% CI, 0.51 to 0.93), 0.83 (95% CI, 0.71 to 0.99), 0.95 (95% CI, 0.80 to 1.14), and 0.76 (95% CI, 0.61 to 0.95) for discharge SBPs <100, 100 to 119, 140 to 159, and ≥160 mm Hg, respectively.

Conclusions— In this long-term population-based study of patients with heart failure, the association of discharge SBP with mortality followed a U-shaped distribution. Survival was shortened in those with reduced or increased values of discharge SBP.

  D. S Lee , M. J Schull , D. A Alter , P. C Austin , A Laupacis , A Chong , J. V Tu and T. A. Stukel
 

Background— Although approximately one third of patients with heart failure (HF) visiting the emergency department (ED) are discharged home, little is known about their care and outcomes.

Methods and Results— We examined the acute care and early outcomes of patients with HF who visited an ED and were discharged without hospital admission in Ontario, Canada, from April 2004 to March 2007. Among 50 816 patients (age, 76.4±11.6 years; 49.4% men) visiting an ED for HF, 16 094 (31.7%) were discharged without hospital admission. A total of 4.0% died within 30 days from admission, and 1.3% died within 7 days of discharge from the ED. Although multiple (≥2) previous HF admissions (odds ratio [OR], 1.64; 95% CI, 1.14 to 2.31), valvular heart disease (OR, 1.37; 95% CI, 1.00 to 1.84), peripheral vascular disease (OR, 1.41; 95% CI, 1.00 to 1.93), and respiratory disease (OR, 1.33; 95% CI, 1.08 to 1.63) increased the risk of 30-day death among those discharged from the ED, presence of these conditions did not increase the likelihood of admission. Patients were more likely to be admitted if they were older (OR, 1.08; 95% CI, 1.06 to 1.10 per decade), arrived by ambulance (OR, 2.02; 95% CI, 1.93 to 2.12), had a higher triage acuity score (OR, 4.12; 95% CI, 3.84 to 4.42), or received resuscitation in the ED (OR, 2.85; 95% CI, 2.68 to 3.04). In those with comparable predicted risks of death, subsequent 90-day mortality rates were higher among discharged than admitted patients (11.9% versus 9.5%; log-rank P=0.016).

Conclusions— Patients with HF who are discharged from the ED have substantial risks of early death, which, in some cases, may exceed that of hospitalized patients.

  Y Koh , I Kim , J. Y Bae , E. Y Song , H. K Kim , S. S Yoon , D. S Lee , S. S Park , M. H Park , S Park and B. K. Kim
  Background

Differences in the clinical course of secondary acute myeloid leukemia according to the type of the preceding disorders are not defined. We compared the outcomes of therapy-related acute myeloid leukemia, acute myeloid leukemia following myelodysplastic syndrome and acute myeloiod leukemia following myeloproliferative neoplasm. We also intended to find prognostic factors in secondary acute myeloid leukemia overall.

Methods

Retrospective medical record review at Seoul National University Hospital was performed. We assessed response to induction chemotherapy and overall survival.

Results

Ninety-five secondary acute myeloid leukemia patients (median age of 56.4 years) were analyzed. Twenty-six, 57 and 12 patients had therapy-related leukemia, leukemia following myelodysplastic syndrome and myeloproliferative neoplasm, respectively. For patients receiving induction chemotherapy, complete remission rate was 47.5% and complete remission rate was different according to the type of the preceding disorders (P = 0.004). Compared to therapy-related leukemia (P = 0.027) and leukemia following myelodysplastic syndrome (P = 0.050), leukemia following myeloproliferative neoplasm had shorter overall survival. In secondary leukemia, presence of trisomy 8 had a prognostic impact (P = 0.003) along with cytogenetic risk group (P = 0.016). In multivariate analysis, the type of the preceding disorders (P = 0.026), 5q deletion (P = 0.015) and trisomy 8 (P = 0.040) were independent prognostic factors.

Conclusions

Prognosis of secondary acute myeloid leukemia was different according to the type of the preceding disorders with the worst prognosis in leukemia following myeloprolfierative neoplasm. Along with cytogenetic risk grouping, trisomy 8 had a poor prognostic impact in secondary acute myeloid leukemia.

 
 
 
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