Sooyoung Kim

Increased oxidative stress in normal-weight postmenopausal women with metabolic syndrome compared with metabolically healthy overweight/obese individuals

OBJECTIVE The purpose of this study was to assess whether the metabolically healthy overweight/obese phenotype is associated with decreased oxidative stress compared with normal-weight individuals with metabolic syndrome (MetS). MATERIALS/METHODS Plasma oxidized LDL (ox-LDL) and urinary 8-epi-prostaglandin F2α (8-epi-PGF2α) were analyzed in a cross-sectional study of 1846 healthy postmenopausal women. Participants were classified by presence (n=569) or absence (n=1277) of MetS and by BMI (18.5-24.9kg/m(2)=normal weight, n=1254; ≥25kg/m(2)=overweight/obese, n=592). MetS was diagnosed with the modified National Cholesterol Education Program Adult Treatment Panel III criteria. RESULTS Compared to normal weight women with MetS (n=296), metabolically healthy overweight/obese women (n=319) showed lower blood pressure, triglyceride, and glucose and higher HDL cholesterol, adiponectin, and LDL particle size. Ox-LDL was higher in overweight/obese women without MetS than in normal weight women without MetS (n=958) but was lower than in women with MetS. Urinary 8-epi-PGF2α level was about 11% lower in women without MetS than in women with MetS. Normal weight women with MetS had greater odds of having ox-LDL (multivariate odds ratio [OR] 2.42, 95% CI: 1.65-3.55) and 8-epi-PGF2α (OR 1.49; CI: 1.03-2.14) levels in the top quartile compared to normal weight women without MetS after adjusting for age, drinking, smoking, total- and LDL-cholesterol, and high sensitivity C-reactive protein. Additionally, there was no significant correlation between ox-LDL and 8-epi-PGF2α. CONCLUSIONS The metabolically healthy overweight/obese phenotype was associated with a better overall metabolic profile and less oxidative stress than that observed in normal weight individuals with MetS. Furthermore, there was a lack of association between ox-LDL and 8-epi-PGF2α.

Nonlinear Color-Metallicity Relations of Globular Clusters. III. On the Discrepancy in Metallicity between Globular Cluster Systems and Their Parent Elliptical Galaxies

One of the conundrums in extragalactic astronomy is the discrepancy in observed metallicity distribution functions (MDFs) between the two prime stellar components of early-type galaxies—globular clusters (GCs) and halo field stars. This is generally taken as evidence of highly decoupled evolutionary histories between GC systems and their parent galaxies. Here we show, however, that new developments in linking the observed GC colors to their intrinsic metallicities suggest nonlinear color-to-metallicity conversions, which translate observed color distributions into strongly peaked, unimodal MDFs with broad metal-poor tails. Remarkably, the inferred GC MDFs are similar to the MDFs of resolved field stars in nearby elliptical galaxies and those produced by chemical evolution models of galaxies. The GC MDF shape, characterized by a sharp peak with a metal-poor tail, indicates a virtually continuous chemical enrichment with a relatively short timescale. The characteristic shape emerges across three orders of magnitude in the host galaxy mass, suggesting a universal process of chemical enrichment among various GC systems. Given that GCs are bluer than field stars within the same galaxy, it is plausible that the chemical enrichment processes of GCs ceased somewhat earlier than that of the field stellar population, and if so, GCs preferentially trace the major, vigorous mode of star formation events in galactic formation. We further suggest a possible systematic age difference among GC systems, in that the GC systems in more luminous galaxies are older. This is consistent with the downsizing paradigm whereby stars of brighter galaxies, on average, formed earlier than those of dimmer galaxies; this additionally supports the similar nature shared by GCs and field stars. Although the sample used in this study (the Hubble Space Telescope Advanced Camera for Surveys/Wide Field Channel, WFPC2, and WFC3 photometry for the GC systems in the Virgo galaxy cluster) confines our discussion to R Re for giant ellipticals and 10 Re for normal ellipticals, our findings suggest that GC systems and their parent galaxies have shared a more common origin than previously thought, and hence greatly simplify theories of galaxy formation.

Determining Photosensor Conditions of a Daylight Dimming Control System Using Different Double-skin Envelope Configurations

Daylight responsive dimming control systems are analysed in a small office with a double-skin envelope to recommend better control alternatives for achieving target illuminance and better energy savings. Computer simulations are performed for photosensors positioned at three different locations in three different shielding conditions. These are applied in both northwards and southwards facing rooms. Daylight conditions included three sky types at different times of the day and year. Shading device conditions are: a horizontal blind on the external envelope, a combination of a horizontal blind on an external envelope and a retractable shading device on an internal envelope. A partially-shielded condition generally achieved good dimming performance under clear and intermediate cloudy skies. Regardless of position, the unshielded photosensors generally fails to achieve target illuminance, providing excessive dimming levels for all tested daylight conditions. Reasonable lighting energy savings are achieved. The savings were not critically influenced by the photosensor positions, but rather are impacted significantly by the sky conditions. Linear prediction models are studied to determine the relationship between photosensor signals and workplane illuminance according to photosensor conditions. The models are acceptable with low significance levels. The linear correlation is best for the partially-shielded condition, but the correlation is weaker for the fully-shielded photosensor.

Red blood cell distribution width predicts early mortality in patients with acute dyspnea.

BACKGROUND Red blood cell distribution width (RDW) has been shown to predict clinical outcomes in cardiovascular diseases. We studied whether RDW is useful to predict early mortality in patients with acute dyspnea at an emergency department (ED). METHODS We retrospectively analyzed 907 patients with acute dyspnea who visited the ED from January 2009 to May 2009. Primary outcome was 30-day mortality. RESULTS Acute decompensated heart failure (29.9%) was the most common adjudicated discharge diagnosis followed by cancer (14.8%) and pneumonia (12.5%). There was a stepwise increase of 30-day mortality risk from lowest (RDW<12.9%) to highest (RDW>14.3%) RDW tertiles (1.4% vs. 8.3% vs. 18.3%; log-rank P<0.001). In multivariate Cox hazard analysis, RDW was an independent predictor of 30-day mortality after adjusting for other risk factors (HR 1.23; 95% CI 1.11-1.36; P<0.001). Adding RDW to conventional clinical predictors significantly improved prediction for 30-day mortality as measured by the area under the ROC curve (AUC, from 0.873 to 0.885; P=0.023) and the net reclassification improvement (NRI=14.1%; P<0.001)/integrated discrimination improvement (IDI=0.038; P=0.006). CONCLUSIONS Our findings suggest that RDW measured at ED is an independent and additive predictor of early mortality in patients with acute dyspnea.

The benefit of microsatellite instability is attenuated by chemotherapy in stage II and stage III gastric cancer: Results from a large cohort with subgroup analyses

We previously reported that the prognosis of microsatellite instability high (MSI‐H) gastric cancer is similar to that of MSI‐low/microsatellite stable (MSI‐L/MSS) gastric cancer. The reason for this seemed to be related to the effects of chemotherapy. To verify this hypothesis, we expanded the study population and reanalyzed the prognosis of MSI‐H gastric cancer. Data from 1,276 patients with Stage II and III gastric cancer who underwent gastrectomy with curative intent between January 2005 and June 2010 were reviewed. The prognosis of MSI‐H tumors in comparison with MSI‐L/MSS tumors was analyzed, according to the administration of chemotherapy and other clinicopathologic features. A total of 361 (28.3%) patients did not receive chemotherapy (MSI‐H = 47 and MSI‐L/MSS = 314), whereas 915 (71.7%) patients did receive chemotherapy (MSI‐H = 58 and MSI‐L/MSS = 857). The hazard ratio of MSI‐H versus MSI‐L/MSS was 0.49 (95% confidence interval: 0.26–0.94, p = 0.031) when chemotherapy was not received and 1.16 (95% confidence interval: 0.78–1.71, p = 0.466) when chemotherapy was received. In subgroup analyses, the prognosis of MSI‐H was better in Stage III, women, with lymph node metastasis, and undifferentiated histology subgroups when chemotherapy was not received. However, in patients treated with chemotherapy, prognosis was worse for MSI‐H tumors in Stage III, undifferentiated histology, and diffuse type subgroups of gastric cancer. In conclusion, MSI‐H tumors were associated with a good prognosis in Stage II and III gastric cancer when patients were treated by surgery alone, and the benefits of MSI‐H status were attenuated by chemotherapy.

Vascular Endothelial Growth Factor, Soluble Fms-Like Tyrosine Kinase 1, and the Severity of Coronary Artery Disease

Background: The association between vascular endothelial growth factor (VEGF), soluble fms-like tyrosine kinase 1 (sFlt-1), and coronary artery disease (CAD) was investigated. Methods: We enrolled 112 hypertensive patients with proven CAD and 112 hypertensive controls matched for age and gender. The severity of CAD was assessed by the most severe clinical presentation of CAD in patients’ history and by the number of diseased vessels. Results: Vascular endothelial growth factor level was lower, whereas sFlt-1 level was higher in the CAD group compared to the controls. Diabetes mellitus (P = .001), smoking (P = .004), and higher sFlt-1 level (P = .01) were independently associated with CAD. Younger age (P = .02), smoking (P = .049), and higher VEGF levels (P = .02) were independently associated with a history of myocardial infarction (MI), whereas higher sFlt-1 level (P = .01) was independently associated with multivessel disease. Conclusion: Plasma sFlt-1 levels are positively associated with the presence of CAD and are associated with angiographical severity of CAD.

C-reactive protein induces p53-mediated cell cycle arrest in H9c2 cardiac myocytes

C-reactive protein (CRP) is one of the most important biomarker for cardiovascular diseases. Recent studies have shown that CRP affects cell survival, differentiation and apoptosis. However, the effect of CRP on the cell cycle has not been studied yet. We investigated the cell cycle alterations and cellular mechanisms induced by CRP in H9c2 cardiac myocytes. Flow cytometry analysis showed that CRP-treated H9c2 cells displayed cell cycle arrest in G0/G1 phase. CRP treatment resulted in a significant reduction in the levels of CDK4, CDK6 and cyclin D1 in a concentration-dependent manner. Interestingly, CRP caused an increase in the p53 accumulation and its phosphorylation on Ser15, leading to induce p21 upregulation. Treatment with a specific p53 inhibitor, PFT-α restored the levels of CDK4 and CDK6. A significant increase of ERK1/2 phosphorylation level was detected in CRP-treated cells. Furthermore, pretreatment of a specific ERK inhibitor resulted in decreased p53 phosphorylation and p21 induction. ERK inhibitor pretreatment induced significant restoration of protein levels of CDK4 and CDK6, leading to re-entry into the cell cycle. In addition, increased phosphorylation of p53 and ERK induced by CRP was considerably reversed by Fc gamma receptor IIIa (FcγRIIIa) knock-down using siRNA. FcγRIIIa siRNA transfection also restored the levels of cell cycle proteins. Our study has provided the first proposal on the novel insights into how CRP directly affects cell cycle in cells.

Takotsubo-like severe left ventricular dysfunction after cesarean delivery in a 28-year old woman.

Takotsubo cardiomyopathy typically affects post-menopausal women who experience severe psychological or physical stress. It can also develop after medical procedures or surgery. Although the underlying mechanism has not been clearly elucidated, catecholamine overload is one of the most plausible etiologies. Herein we report a case of takotsubo-like left ventricular (LV) dysfunction in a 28-year old woman who underwent Cesarean delivery. She presented with acute heart failure and pulmonary edema immediately after the delivery. Her echocardiography showed severe LV dysfunction and apical ballooning. This case is clinically and pathophysiologically similar to peripartum cardiomyopathy.

Nonlinear Color-Metallicity Relations of Globular Clusters. V. Nonlinear Absorption-line Index versus Metallicity Relations and Bimodal Index Distributions of M31 Globular Clusters

Recent spectroscopy on the globular cluster (GC) system of M31 with unprecedented precision witnessed a clear bimodality in absorption-line index distributions of old GCs. Such division of extragalactic GCs, so far asserted mainly by photometric color bimodality, has been viewed as the presence of merely two distinct metallicity subgroups within individual galaxies and forms a critical backbone of various galaxy formation theories. Given that spectroscopy is a more detailed probe into stellar population than photometry, the discovery of index bimodality may point to the very existence of dual GC populations. However, here we show that the observed spectroscopic dichotomy of M31 GCs emerges due to the nonlinear nature of metallicity-to-index conversion and thus one does not necessarily have to invoke two separate GC subsystems. We take this as a close analogy to the recent view that metallicity-color nonlinearity is primarily responsible for observed GC color bimodality. We also demonstrate that the metallicity-sensitive magnesium line displays non-negligible metallicity-index nonlinearity and Balmer lines show rather strong nonlinearity. This gives rise to bimodal index distributions, which are routinely interpreted as bimodal metallicity distributions, not considering metallicity-index nonlinearity. Our findings give a new insight into the constitution of M31s GC system, which could change much of the current thought on the formation of GC systems and their host galaxies.

Improvement of indoor living environment by occupants' preferences for heat recovery ventilators in high-rise residential buildings

This study examined the influence of heat recovery ventilators (HRVs) on energy savings and indoor air quality (IAQ) in high-rise residential buildings. Field measurements were performed in four residential units, which were validated by computer simulations and estimated the total annual energy consumption. The operation schedules for HRVs were determined by a survey of residents. Field measurement results indicate that HRVs could effectively improve IAQ and afford effective energy savings. The indoor concentrations of formaldehyde were reduced by 54.6% after HRVs were operated for 24 h. The initial concentration was reduced by 82% after 168 h. Toluene was the dominant volatile organic compounds (VOCs) in the indoor air. Its initial concentration was reduced by 50% and other VOCs were also reduced by 40.1% to 53.1% after HRVs were operated. Annual energy savings of up to 20.26% were predicted when HRVs were operated for 24 h continuously, exchanging sensible and latent heat. HRVs could save energy more effectively in winter than in summer due to the greater temperature difference between outdoor and indoor air. Based on the preferred operation schedules of homes surveyed, an annual energy savings could be as high as 8.52%.