Sun-Young Kim

Association of Body Size Measurements and Mammographic Density in Korean Women: The Healthy Twin Study

Background: Both greater body size and higher mammographic density seem to be associated with a risk of breast cancer. To understand a mechanism through which body size confers a higher risk of breast cancer, associations between mammographic measures and various measures of body size were examined. Method: Study subjects were 730 Korean women selected from the Healthy Twin study. Body size measurements were completed according to standard protocol. Mammographic density was measured from digital mammograms using a computer-assisted method from which the total area and the dense area of the breast were calculated, and nondense area and percent of dense area were straightforwardly derived. Linear mixed models considering familial correlations were used for analyses. Results: Total and nondense areas were positively associated with current body mass index (BMI), BMI at 35 years, total fat percent, waist circumference, and waist-hip ratio, whereas percent dense area was inversely associated with these characteristics in both premenopausal and postmenopausal women. Height was not associated with any mammographic measure. Total and nondense areas had strong positive genetic correlations with current BMI, total fat percent, waist circumference, and waist-hip ratio, whereas percent dense area had strong inverse genetic correlations with these body size measurements. Conclusion: Mammographic density and obesity are inversely associated with each other possibly from common genetic influences that have opposite effects on mammographic density and obesity in Korean women. Impact: The association between obesity and breast cancer does not seem to be mediated through mammographic density. Cancer Epidemiol Biomarkers Prev; 19(6); 1523–31. ©2010 AACR.

Multivalent Polymer Nanocomplex Targeting Endosomal Receptor of Immune Cells for Enhanced Antitumor and Systemic Memory Response

We have designed and synthesized linear polymer-based nanoconjugates and nanocomplexes bearing multivalent immunostimulatory ligands and also demonstrated that the synthetic multivalent nanocomplexes led to an enhanced stimulation of immune cells inu2005vitro and antitumor and systemic immune memory response inu2005vivo. We have developed hyaluronic acid (HA)-based multivalent nanoconjugates and nanocomplexes for enhanced immunostimulation through the combination of multivalent immune adjuvants with CpG ODNs (as a TLR9 ligand) and cationic poly(L-lysine) (PLL; for the enhancement of cellular uptake). The multivalent HA-CpG nanoconjugate efficiently stimulated the antigen-presenting cells and the multivalent PLL/HA-CpG nanocomplex also led to an enhanced cellular uptake as well as continuous stimulation of endosomal TLR9. The mice vaccinated with dendritic cells treated with the multivalent nanocomplex exhibited tumor growth inhibition as well as a strong antitumor memory response.

Synthetic vaccine nanoparticles target to lymph node triggering enhanced innate and adaptive antitumor immunity

In this study, synthetic vaccine nanoparticles (SVNPs) that efficiently targeted lymph nodes, where immune responses against foreign antigens are primed, were developed to enhance antitumor immunity. The size (20-70xa0nm) and surface character (amination) of poly(γ-glutamic acid)-based SVNPs were selected for effective loading and delivery (i.e., migration and retention) of model tumor antigen (OVA) and toll-like receptor 3 agonist (poly (I:C)) to immune cells in lymph nodes. Antigen-presenting cells treated with SVNP-OVA and SVNP-IC showed higher uptake of OVA and poly (I:C) and higher secretion of inflammatory cytokines (TNF-α, IL-6) and type I interferon (IFN-α, IFN-β) than those treated with OVA and poly (I:C) alone. Inxa0vivo analysis revealed higher levels of activation markers, inflammatory cytokines, and type I IFNs in the lymph nodes of mice immunized with SVNP-IC compared to those of mice in other groups. SVNP-IC-treated mice showed significantly greater inxa0vivo natural killer cell expansion/activation (NK1.1+ cells) and CD8+ T cell response (CD8+ INF-γ+ cells) in innate and adaptive immunity, respectively. Both preventive and therapeutic vaccination of EG7-OVA tumor-bearing mice using the simultaneous injection of both SVNP-OVA and SVNP-IC induced higher antitumor immunity and inhibited tumor growth.

High-Density Lipoprotein Cholesterol, Obesity, and Mammographic Density in Korean Women : The Healthy Twin Study

Background High-density lipoprotein cholesterol (HDL-C) is reported to be associated with breast cancer risk. To better understand this association, we examined the relationship between HDL-C and mammographic density, a putative intermediate risk factor for breast cancer. Methods The study subjects were 711 Korean women from the Healthy Twin study. Lipid parameters were assayed enzymatically in fresh sera, and percent dense area (PDA) and absolute dense area were measured from digital mammograms using a computer-assisted method. Results PDA was positively associated with HDL-C in both premenopausal and postmenopausal women in a multivariable-adjusted linear mixed model, but the association did not persist when the model was additionally adjusted for body mass index (BMI). BMI was inversely associated with PDA, and this association did not change after additional adjustment for any lipid parameter. Multivariable-adjusted analysis showed that there were significant additive genetic cross-trait correlations between PDA and both HDL-C (coefficient, 0.175) and triglyceride (coefficient, −0.262). However, those correlations disappeared after additional adjustment for BMI. Conclusions HDL-C alone is unlikely to increase the risk of breast cancer in Korean women, particularly through changes in breast parenchyma that are apparent in mammographic density. BMI should be included in studies using analytical models where mammographic density is used as an intermediate risk factor for breast cancer.

Synthesis of conjugated polymer nanoparticles with core-shell structure for cell imaging and photodynamic cancer therapy

Conjugated polymer nanoparticles were successfully capped with a commercially available triblock copolymer Pluronic F127® to form stable nanoparticles with the potential for photodynamic therapy (PDT) of cancer cells. PDT is known as an effective, simple treatment method without the need for surgery. Investigations on the particle structure revealed that the nanoparticles were fabricated with a core-shell structure of ~192 nm. The PDT effects of the nanoparticles on HeLa cancer cells were investigated via cell imaging and cytotoxicity tests. The nanoparticles were biocompatible and were easily internalized by HeLa cells. Moreover, the nanoparticles efficiently generated reactive oxygen species to kill cancer cells under UV irradiation. Therefore, the nanoparticles have promising applications for cancer cell imaging and therapy.

Aminated nanomicelles as a designer vaccine adjuvant to trigger inflammasomes and multiple arms of the innate immune response in lymph nodes

In this study, we suggest a designer vaccine adjuvant that can mimic the drainage of pathogens into lymph nodes and activate innate immune response in lymph nodes. By the amination of multivalent carboxyl groups in poly-(γ-glutamic acid) (γ-PGA) nanomicelles, the size was reduced for rapid entry into lymphatic vessels, and the immunologically inert nanomicelles were turned into potential activators of inflammasomes. Aminated γ-PGA nanomicelles (aPNMs) induced NLRP3 inflammasome activation and the subsequent release of proinflammatory IL-1β. The NLRP3-dependent inflammasome induction mechanism was confirmed through enzyme (cathepsin B and caspase-1) inhibitors and NLRP3 knockout mice model. After the aPNMs were combined with a clinically evaluated TLR3 agonist, polyinosinic–polycytidylic acid sodium salt (aPNM-IC), they triggered multiple arms of the innate immune response, including the secretion of pro-inflammatory cytokines by both inflammasomes and an inflammasome-independent pathway and the included type I interferons.

Results of a Survey of Residents Who Experience Pregnancy and Delivery

PURPOSEnA growing number of residents bear children during residency training. This study was conducted to examine the pregnancy and maternity leave experiences of women who delivered infants during their residency training.nnnMETHODSnFrom March 2007 through June 2007, we surveyed 94 women who had given birth during their residency training during the past 5 years from the survey date. Participants were recruited using snowball sampling.nnnRESULTSnMost of the respondents (70.2%) delivered in the 3rd and 4th year of residency. The average length of leave was 68.9 days, and more than half (54.3%) of the women expressed that a maternity leave policy was not formally established in the department. In general, participants believed that having a child during residency was difficult (mean=4.18 in 5-point Likert scale), and this perception was inversely related with systematic departmental support.nnnCONCLUSIONnPregnancy is a special challenge for residents, with regard to not only physical overexertion but also psychosocial impacts on pregnant residents and their colleagues. However, most current residency programs do not have written policies on pregnancy. A formal policy and more flexible curriculum can help both the training program and the pregnant resident.

Association between physical activity and depressive symptoms in general adult populations: An analysis of the dose-response relationship

This study investigated the dose-response relationship between physical activity and depression. We collected data from 99,846 participants who had no medical contraindications to exercise. Using the short-form Korean version of the International Physical Activity Questionnaire, total physical activity was computed in metabolic equivalents (METs). We used the Center for Epidemiologic Studies Rating Scale for Depression to assess depressive symptoms and set a cut off score of 21. Logistic regression analyses were used to determine any relationships. To assess the effect of sex difference on the association between physical activity and depression, we stratified our data by sex. Compared with the sedentary group (0-600 METs-min/week), 1-15 times the recommended minimum physical activity was associated with a significantly lower risk of depression in all adults. The optimal range for a lower risk of depression was 2-3 times the recommended minimum. After stratifying our data by sex, we found that optimal ranges were 10-15 times the recommended minimum physical activity in men and 3-5 times in women. This study established a U-shaped dose-response relationship between physical activity and depression. The optimal range and upper threshold for anti-depression effect of physical activity were higher in men than in women.

Impaired facial expression recognition in patients with social anxiety disorder: a case-control study

ABSTRACT Introduction: The aim of this study was to investigate whether social anxiety disorder (SAD) patients have low emotion recognition accuracy, take longer for emotion recognition and tended to interpret a stimulus more negatively than controls. Methods: Fifty-six SAD patients and 56 healthy controls were participated in this study. We evaluated facial emotion recognition using a computer program in which participants chose one of seven emotions as displayed in each of 55 photographs of faces. We compared the accuracy and reaction times of the patients and controls. We further analysed which emotions were selected in the incorrect answers. Results: SAD patients showed delayed reaction times for all emotions except anger and lower accuracy for fear, surprise, neutrality and happiness compared to controls. After applying Bonferroni correction, only delayed reaction time for surprise and happiness were remain significant. Neutrality was not mistaken for a negative emotion at a higher rate by SAD patients than by controls. Conclusion: This result suggests that the alterations of reaction time and accuracy of emotion recognition of SAD patients, especially in emotions with positive valence, play a more important role than negative bias in the cognitive aspects of SAD.