Do Yeon Kim

Prediction of Stroke Subtype and Recanalization Using Susceptibility Vessel Sign on Susceptibility-Weighted Magnetic Resonance Imaging

Background and Purpose— The susceptibility vessel sign (SVS) is a hypointense signal visualized because of the susceptibility effect of thrombi, sensitively detected on susceptibility-weighted magnetic resonance imaging. The relationship of SVS parameters with the stroke subtype and recanalization status after endovascular treatment remains uncertain. Methods— The data from 89 patients with acute stroke caused by anterior circulation infarcts who underwent susceptibility-weighted magnetic resonance imaging before endovascular treatment were examined. Independent reviewers, blinded to the stroke subtype and recanalization status, measured the SVS diameter, length, and estimated volume. The intra- and interrater agreements of the SVS parameters were assessed. Results— The SVS was identified in 78% of the patients. SVS was more commonly associated with cardioembolism than with noncardioembolism (P=0.01). The SVS diameter (P<0.01) and length (P=0.01) were larger in the cardioembolism group. The SVS diameter was larger in the recanalization group (thrombolysis in cerebral infarction ≥2b) than in the nonrecanalization group (P=0.04). Multivariable analysis revealed that the SVS diameter was an independent predictor of cardioembolism (adjusted odds ratio, 1.97; 95% confidence interval, 1.34–2.90; P<0.01). There was no significant association between the SVS volume and the recanalization status (adjusted odds ratio, 1.003; 95% confidence interval, 0.999–1.006; P=0.12). The optimal cutoff value of the SVS diameter for the cardioembolism was 5.5 mm (sensitivity, 45.6%; specificity, 93.8%). Conclusions— Increased SVS diameter on susceptibility-weighted magnetic resonance imaging may predict cardioembolism. No clear association was found between SVS volume and endovascular recanalization.

Ceria–Zirconia Nanoparticles as an Enhanced Multi‐Antioxidant for Sepsis Treatment

The two oxidation states of ceria nanoparticles, Ce3+ and Ce4+ , play a pivotal role in scavenging reactive oxygen species (ROS). In particular, Ce3+ is largely responsible for removing O2- and . OH that are associated with inflammatory response and cell death. The synthesis is reported of 2u2005nm ceria-zirconia nanoparticles (CZ NPs) that possess a higher Ce3+ /Ce4+ ratio and faster conversion from Ce4+ to Ce3+ than those exhibited by ceria nanoparticles. The obtained Ce0.7 Zr0.3 O2 (7CZ) NPs greatly improve ROS scavenging performance, thus regulating inflammatory cells in a very low dose. Moreover, 7CZ NPs are demonstrated to be effective in reducing mortality and systemic inflammation in two representative sepsis models. These findings suggest that 7CZ NPs have the potential as a therapeutic nanomedicine for treating ROS-related inflammatory diseases.

Biocompatible custom ceria nanoparticles against reactive oxygen species resolve acute inflammatory reaction after intracerebral hemorrhage

Intracerebral hemorrhage (ICH) is a devastating subtype of stroke with a high mortality rate, for which there currently is no effective treatment. A perihematomal edema caused by an intense inflammatory reaction is more deleterious than the hematoma itself and can result in neurological deterioration and death. Ceria nanoparticles (CeNPs) are potent free radical scavengers with potential for biomedical applications. As oxidative stress plays a major role in post-ICH inflammation, we hypothesized that CeNPs might protect against ICH. To test this hypothesis, core CeNPs were synthesized using a modified reverse micelle method and covered with phospholipid-polyethylene glycol (PEG) to achieve biocompatibility. We investigated whether our custom-made biocompatible CeNPs have protective effects against ICH. The CeNPs reduced oxidative stress, hemin-induced cytotoxicity, and inflammation in vitro. In a rodent ICH model, intravenously administered CeNPs were mainly distributed in the hemorrhagic hemisphere, suggesting that they could diffuse through the damaged blood–brain barrier. Moreover, CeNPs attenuated microglia/macrophage recruitment around the hemorrhagic lesion and inflammatory protein expression. Finally, CeNP treatment reduced the brain edema by 68.4% as compared to the control. These results reveal the great potential of CeNPs as a novel therapeutic agent for patients with ICH.

Customized lipid-coated magnetic mesoporous silica nanoparticle doped with ceria nanoparticles for theragnosis of intracerebral hemorrhage

Intracerebral hemorrhage (ICH), caused by the sudden rupture of an artery within the brain, is a devastating subtype of stroke, which currently has no effective treatment. Intense inflammatory reactions that occur in the peri-hematomal area after ICH are more deleterious than the hematoma itself, resulting in subsequent brain edema and neurologic deterioration. Thus, we developed lipid-coated magnetic mesoporous silica nanoparticles doped with ceria nanoparticles (CeNPs), abbreviated as LMCs, which have both potent anti-inflammatory therapeutic effects via scavenging reactive oxygen species and help in increasing the efficacy of magnetic resonance imaging enhancement in the peri-hematomal area. LMCs consist of mesoporous silica nanoparticle-supported lipid bilayers, which are loaded with large amounts of CeNPs for scavenging of reactive oxygen species, and iron oxide nanoparticles for magnetic resonance imaging contrast. LMCs loaded with CeNPs exhibited strong anti-oxidative and anti-inflammatory activities in vitro. In the rodent ICH model, intracerebrally injected LMCs reached the peri-hematomal area and were engulfed by macrophages, which were clearly visualized by magnetic resonance imaging of the brain. Moreover, LMCs reduced inflammatory macrophage infiltration, and thus significantly reduced brain edema. Finally, LMC treatment markedly improved neurologic outcomes of the animals with ICH. Thus, LMC is the first nanobiomaterial that successfully showed theragnostic effects in ICH.

Physical Activity Frequency and the Risk of Stroke: A Nationwide Cohort Study in Korea

Background The current guideline recommends moderate‐ to vigorous‐intensity physical activity (PA) at least 40 min/day for 3 to 4 days/week. Although recent evidence has demonstrated that low‐dose PA could reduce cardiovascular mortality, the relationship between low‐dose PA and the risk of stroke remains uncertain. Methods and Results Using data from a nation‐wide sample cohort in Korea, we examined 336 326 individuals who received a general health examination between 2009 and 2010. Level of PA was assessed using a questionnaire for weekly PA frequencies regarding 3 intensity categories: light, moderate, and vigorous. Moderate‐ to vigorous‐intensity PA (MVPA) was classified into 4 frequency categories: none, 1 to 2, 3 to 4, or ≥5 times/week. Cox proportional hazard models were constructed to estimate the risk of stroke. During the average follow‐up of 3.6 years, 2213 stroke cases occurred. MVPA was none in 50%, 1 to 2 times/week in 20%, 3 to 4 times/week in 13%, and ≥5 times/week in 18% of the cohort. Individuals with MVPA 1 to 2 times/week had a 16% reduced risk of stroke (adjusted hazard ratio, 0.84; 95% confidence interval, 0.73–0.96) compared with those with no MVPA. The population attributable fraction of no MVPA was 12%, which was the second most important risk factor for a stroke after hypertension. Conclusions Even 1 to 2 times a week of MVPA might be beneficial to prevent a first‐ever stroke in the general population, although a quantitative validation of the questionnaire is needed. From a public health perspective, we need to encourage inactive people to start exercising with more‐achievable goals.

Gamma-glutamyl transferase predicts future stroke: A Korean nationwide study: GGT Predicts Future Stroke

Although gamma‐glutamyl transferase (GGT) is generally regarded as an alternative biomarker for alcohol consumption, its independent role in vascular diseases emerged recently. However, its role in stroke remains unknown. The aim of this study is to clarify the impact of GGT on stroke in a large‐sized, national, standardized population cohort in Korea.

Branch-duct intraductal papillary mucinous neoplasm and embolic stroke of unknown cause.

BACKGROUNDnIn many embolic strokes, the specific embolic source might be uncertain. When we found asymptomatic branch-duct intraductal papillary mucinous neoplasms (BD-IPMNs) in patients with ischemic stroke of unknown cause, most of gastroenterologists might undervalue it as a potential thromboembolic sources.nnnMETHODSnWe report 4 patients with embolic stroke of unknown cause and incidental BD-IPMNs.nnnRESULTSnMagnetic resonance imaging revealed multiple embolic infarctions. Recommended cardiac examinations, such as 24-hour Holter monitoring and transthoracic and transesophageal echocardiography, were normal. Other cancer markers and molecular markers of hypercoagulopathy were normal. On abdominal computed tomography scan, performed to detect hidden malignancy, a low attenuated lesion with a diameter of less than 3xa0cm was observed in the pancreas.nnnCONCLUSIONnAlthough BD-IPMNs are associated with a lower rate of malignancy than main-duct IPMNs, the BD-IPMNs had some malignant potential and frequently coexist with extrapancreatic or intrapancreatic cancers. Therefore, we suggest that, in some cases, the BD-IPMNs might be considered as a thromboembolic source.