A comparative study on the Cs adsorption/desorption and structural changes in different clay minerals.

We investigated the structural changes in clay minerals after Cs adsorption and understood their low desorption efficiency using an ion-exchanger. We focused on the role of interlayers in Cs adsorption and desorption in 2:1 clay minerals, namely illite, hydrobiotite, and montmorillonite, using batch experiments and XRD and EXAFS analyses. The adsorption characteristics of the clay minerals were analyzed using cation exchange capacity (CEC), maximum adsorption isotherms (Qmax), and radiocesium interception potential (RIP) experiments. Although illite showed a low CEC value, it exhibited high selectivity for Cs with a relatively high RIP/CEC ratio. The Cs desorption efficiency after treatment with a NaCl ion exchanger was the highest for illite (74.3%), followed by hydrobiotite (45.5%) and montmorillonite (30.3%); thus, Cs adsorbed onto planar sites, rather than on interlayers or frayed edge sites (FESs), is easily desorbed. After NaCl treatment, XRD analysis showed that the low desorption efficiency was due to the collapse of the interlayer-fixed Cs, which tightly narrowed the interlayers' hydrobiotite due to the ion exchange of divalent cations (Mg2+ or Ca2+) into the monovalent cation (Na+). Moreover, EXAFS analysis showed that hydrobiotite formed inner-sphere structures after NaCl desorption, indicating that it was difficult to remove Cs from NaCl desorption due to the collapsed hydrobiotite and montmorillonite interlayers as well as the strong bonding in FESs of illite. In contrast, chelation desorption using oxalic acid effectively dissolved the narrowed interlayers of hydrobiotite (98%) and montmorillonite (85.26%), enhancing the desorption efficiency. Therefore, low desorption efficiency for Cs clays using an ion exchanger was caused by the collapsed interlayer due to the exchange between monovalent cation and divalent cation.

Designer biochar with enhanced functionality for efficient removal of radioactive cesium and strontium from water.

Radioactive elements released into the environment by accidental discharge constitute serious health hazards to humans and other organisms. In this study, three gasified biochars prepared from feedstock mixtures of wood, chicken manure, and food waste, and a KOH-activated biochar (40% food waste + 60% wood biochar (WFWK)) were used to remove cesium (Cs+) and strontium (Sr2+) ions from water. The physicochemical properties of the biochars before and after adsorbing Cs+ and Sr2+ were determined using X-ray diffraction (XRD), Fourier-transform infrared (FT-IR) spectroscopy, extended X-Ray absorption fine structure (EXAFS) spectroscopy, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDX). The WFWK exhibited the highest adsorption capacity for Cs+ (62.7 mg/g) and Sr2+ (43.0 mg/g) among the biochars tested herein. The removal of radioactive 137Cs and 90Sr exceeded 80% and 47%, respectively, in the presence of competing ions like Na+ and Ca2+. The functional groups present in biochar, including -OH, -NH2, and -COOH, facilitated the adsorption of Cs+ and Sr2+. The Cs K-edge EXAFS spectra revealed that a single coordination shell was assigned to the Cs-O bonding at 3.11 Å, corresponding to an outer-sphere complex formed between Cs and the biochar. The designer biochar WFWK may be used as an effective adsorbent to treat radioactive 137Cs- and 90Sr-contaminated water generated during the operation of nuclear power plants and/or unintentional release, owing to the enrichment effect of the functional groups in biochar via alkaline activation.

Characteristic and remediation of radioactive soil in nuclear facility sites: a critical review.

A huge amount of radioactive soil has been generated through decommissioning of nuclear facilities around the world. This review focuses on the difficulties and complexities associated with the remediation of radioactive soils at the site level; therefore, laboratory studies were excluded from this review. The problems faced while remediating radioactive soils using techniques based on strategies such as dry separation, soil washing, flotation separation, thermal desorption, electrokinetic remediation, and phytoremediation are discussed, along with appropriate examples. Various factors such as soil type, particle size, the fraction of fine particles, and radionuclide characteristics that strongly influence radioactive soil decontamination processes are highlighted. In this review, we also survey and compare the pool of available technologies currently being used for the remediation of radionuclide-contaminated soils, as well as the economic aspects of soil remediation using different techniques. This review demonstrates the importance of the integrated role of various factors in determining the effectiveness of the radioactive soil decontamination process.

Experimental Demonstration of 3 × 3 MIMO LED-to-LED Communication Using RGB Colors.

Optical wireless communication (OWC) is one of the promising candidates for beyond fifth-generation communication (B5G). Depending on the type of transmitters, receivers, and information carriers applied in the system, OWC can be categorized into visible light communication, light fidelity, free-space optical communication, optical camera communication, etc. In addition to these OWC subcategories, this paper proposes light-emitting diode (LED)-to-LED communication as another subcategory of OWC technique. Furthermore, we show an experimental demonstration of the multiple-input multiple-output (MIMO) LED-to-LED communication system using red, green, and blue colored LEDs. We believe that LED-to-LED communication is an effective solution to resolve the communication burden arising from massive connectivity in B5G internet of things. Along with the measurement results of the transmitter LED, receiver LED, and the channel properties, it is shown that the MIMO LED-to-LED system is able to successfully recover the transmitted signal with low inter-channel interferences due to the receiver LED's unique characteristics. Finally, the bit error rate (BER) performance of the MIMO LED-to-LED system is shown in comparison with the BER performance of the single-input single-output (SISO) LED-to-LED system. We successfully implemented the 3 × 3 MIMO LED-to-LED communication system using RGB colors at a data rate of 30.62 kbps over a 10 cm transmission distance along with direct current biased optical orthogonal frequency division multiplexing (DCO-OFDM) modulation and zero-forcing (ZF) equalizer.

Sorption behavior of cesium on silt and clay soil fractions.

The effect of clay mineral composition on Cs adsorption behavior of silt and clay fractions (SC-fractions) of soil was investigated. Surface soil samples were collected within 2 km of Kori and Wolsong nuclear power plants in South Korea, and SC-fractions (<20 µm) were separated. The physicochemical properties of SC-fractions and types of clay minerals contained in the SC-fractions were analyzed. The cesium adsorption capacity of the SC-fractions, and affinity between the SC-fractions and Cs, were investigated by isothermal adsorption analysis using the dual-site Langmuir adsorption model. To understand selective adsorption of Cs, the radiocesium interception potential and distribution coefficient of the SC-fractions were analyzed in the presence or absence of competing ions. The radiocesium distribution coefficient of the SC-fractions showed a trend similar to that of the Langmuir sorption coefficient of high-affinity binding sites for Cs in the SC-fractions. The SC-fractions of Kori soils that contain only non-expandable clay minerals including highly weathered mica had low Cs adsorption capacity. However, the SC-fractions of Kori soils showed higher Cs adsorption selectivity compared to the SC-fractions of Wolsong soils containing expandable clay minerals and micaceous mineral with a low degree of weathering. It is predicted that the highly weathered micas have high affinity to Cs, and such clay minerals contribute the most to the adsorption process in dilute solutions.

Biflavonoid-rich fraction from Daphne pseudomezereum var. koreana Hamaya exerts anti-inflammatory effect in an experimental animal model of allergic asthma.

ETHNOPHARMACOLOGICAL RELEVANCE: Daphne pseudomezereum var. koreana Hamaya is distributed in the Gangwon-do of South Korea and is traditionally used to treat chronic inflammatory diseases, including rheumatoid arthritis. AIM OF THE STUDY: We investigated the anti-inflammatory effect of biflavonoid-rich fraction (BF) obtained from an extract of D. pseudomezereum leaves on lipopolysaccharide (LPS)-stimulated RAW264.7 macrophages and mouse model of ovalbumin (OVA)-induced allergic asthma. MATERIALS AND METHODS: Neochamaejasmin B (NB) and chamaejasmin D (CD) were spectroscopically characterized as major components of BF obtained from the leaves of D. pseudomezereum. RAW264.7 cells pretreated with NB, CD and BF and activated by LPS (500 ng/ml) were used to assess the anti-inflammatory effects of these materials in vitro. To evaluate the protective effect of BF on allergic asthma, female BALB/c mice were sensitized to OVA by intraperitoneal (i.p.) injection and treated with BF by oral administration (15 or 30 mg/kg). RESULTS: Pretreatment with BF inhibited LPS-stimulated nitric oxide (NO), TNF-α and IL-6, and led to upregulation of heme oxygenase-1 (HO-1) in RAW264.7 macrophages. Orally administered BF significantly inhibited the recruitment of eosinophils and the production of IL-5, IL-6, IL-13 and MCP-1 as judged by the analysis of BALF from OVA-induced asthma animal model. BF also decreased the levels of IgE in the serum of asthmatic mice. BF suppressed the influx of inflammatory cells into nearby airways and the hypersecretion of mucus by the airway epithelium of asthmatic mice. In addition, the increase in Penh in asthmatic mice was reduced by BF administration. Furthermore, BF led to Nrf2 activation and HO-1 induction in the lungs of mice. CONCLUSIONS: These data have shown the anti-asthmatic effects of BF, and therefore we expect that BF may be a potential candidate as a natural drug/nutraceutical for the prevention and treatment of allergic asthma.

Cs desorption behavior during hydrothermal treatment of illite with oxalic acid.

The desorption of radioactive cesium (Cs) in soil is influenced by the clay mineral type, adsorption site, and concentration of Cs. In this study, experiments to detect desorption of non-radioactive and radioactive Cs from illite using oxalic acid were performed for 2 days at 70 °C in hydrothermal conditions. The results showed that the 133Cs removal efficiency by oxalic acid and inorganic acid treatment was similar at high concentration (22.86 mmol/kg) of non-radioactive 133Cs. In the radioactive 137Cs experiment, the removal efficiency by oxalic acid was higher than that by inorganic acid at low concentration (0.79 × 10-6 mmol/kg) of radioactive 137Cs. Based on the illite hypothetical frayed edge site (FES) concentration of 0.612 mmol/kg, the results suggested that 137Cs was preferentially adsorbed to FES on illite. The 137Cs at low concentration was difficult to remove because it was irreversible adsorption to FES, while the non-radioactive Cs at high concentration was mainly adsorbed to planar sites, and so was easy to desorb by ion exchange. Based on the results of NMR, FTIR, and XPS analyses, we concluded that the higher efficiency of 137Cs removal at low concentration by oxalic acid treatment than by treatment with inorganic acid was because of chelation effects associated with the complexation of oxalic acid (ligands) and metal ions in irreversible site (FES).

Application of polyethylenimine-coated magnetic nanocomposites for the selective separation of Cs-enriched clay particles from radioactive soil.

The separation of Cs-enriched fine particles is a highly effective way to reduce the volume and radioactivity of contaminated soil. This work demonstrated the application of polyethylenimine (PEI)-coated Fe3O4 nanocomposites and a mesh filter for the selective separation of clay particles from Cs-contaminated soil. The PEI coating on the Fe3O4 nanoparticles enhanced the binding force between the magnetic nanoparticles and clay minerals via electrostatic attraction; thus, approximately 100% of the clay particles were magnetically separated from solution by Fe3O4-PEI nanocomposites at a low dose (0.04 g-nanocomposite per g-clay). In separation experiments with soil mixtures, clay- and silt-sized fine particles that had been magnetized by Fe3O4-PEI nanocomposites were selectively separated, and the separation efficiency improved when a mesh filter was added to exclude physically large particles. The combination of magnetic and sieving separation thoroughly separated fine particles from soil by reducing the volume of the magnetic fraction. We also evaluated the magnetic-sieving separation method for the selective removal of clay particles from 137Cs-contaminated soil. The decrease in radioactivity in the treated nonmagnetic fraction, which accounted for 87.5% of the total soil, corresponded to a high decontamination efficiency of approximately 90%. The developed separation technology offers great potential for the efficient remediation of radioactive soil.

Desorption of cesium from hydrobiotite by hydrogen peroxide with divalent cations.

In this study, hydrogen peroxide (H2O2) was used to enhance the cation-exchange treatment for Cs+ desorption from clay minerals. Among various investigated clay minerals, hydrobiotite (HBT), which has interstratified layers of vermiculite and biotite, exhibited the highest Cs+ sorption capacity and the most favorable H2O2 activation because of its high Fe content. In X-ray diffraction analysis, HBT treated with H2O2 and 0.1 M Mg2+ showed substantial changes in its basal spacing, indicating expansion of the interlayer region induced by treatment of H2O2 and strongly hydrated divalent cations. In addition, more than 80% of the Cs+ was readily desorbed from HBT with 35% H2O2 solution and 0.1 M Mg2+ at room temperature. After three cycles under the same treatment conditions (35% H2O2 solution and 0.1 M Mg2+), approximately 99% removal of radioactive Cs+ was achieved. These results suggested that H2O2 treatment with solvated Mg2+ enhanced Cs+ desorption from HBT by altering the interlayer region through intercalation of hydrated divalent cations in conjunction with the H2O2 decomposition reaction.

Selective separation of Cs-contaminated clay from soil using polyethylenimine-coated magnetic nanoparticles.

We evaluated the feasibility of using magnetic nanoparticles (MNPs) coated with polyethylenimine (PEI), a cationic polymer, to remediate radioactive contaminated soil by separating Cs-contaminated clay from the soil. The influences of the solution pH, PEI-to-MNPs mass ratio, and the PEI-MNPs dose on the magnetic separation performance were systematically examined. The highest SE% of illite from solution through electrostatic attraction was approximately 100% at a mass ratio of 0.04 g-PEI-MNPs/g-clay. The PEI coating clearly enhanced the adhesion between MNPs and clay minerals by increasing the quantity of functional amine groups available for adsorbing negatively charged clay minerals. In separation experiments using a soil mixture, the PEI-coated MNPs selectively separated clay- and silt-sized fine particles smaller than 0.038 mm even in the presence of a large amount of sand when used at a low dose (mass ratio of 0.05 g-PEI-MNPs/g-clay) and without pH control. We also used the PEI-MNPs to separate 137Cs-contaminated illite from soil under an external magnetic field. After magnetic separation, the highest removal efficiency achieved for 137Cs removal from the treated soil was 81.7% at a low nanoparticle dosage, which resulted in satisfying the reduction of radioactivity and waste volume. The results clearly demonstrate that the selective separation of Cs-contaminated clay using PEI-coated MNPs is a promising technique for remediating radioactive soil.

Retraction: Engineering of extracellular vesicles as drug delivery vehicles.

[This retracts the article DOI: 10.21037/sci.2017.08.07.].

C-C motif chemokine ligand 2 regulates lps-induced inflammation and ER stress to enhance proliferation of bovine endometrial epithelial cells.

Chemokines play an important role in regulating the complex immune system at the maternal-fetal interface during pregnancy. Among various chemokines, CC motif chemokine ligand 2 (CCL2) plays a role in the recruitment of immune regulatory cells to implantation sites within the endometrium. In cattle, CCL2 is abundantly expressed in the uterine endometrium. However, its intracellular signaling has not been identified. In this study, we examined the effects of CCL2 on bovine endometrial (BEND) cell proliferation. CCL2 stimulated BEND cell proliferation by abundant expression of PCNA, accumulation of cells in the G2/M phase, and activation of the PI3 K/AKT and MAPK signaling pathways. Moreover, CCL2 reduced endoplasmic reticulum stress and restored the inflammation-induced reduction in BEND cell proliferation by regulating the unfolded protein response genes and cytokines. Collectively, these results demonstrated that CCL2 plays a pivotal role in reproductive tissues and may support maternal-fetal interface to improve efficiency of pregnancy.

Chrysin attenuates progression of ovarian cancer cells by regulating signaling cascades and mitochondrial dysfunction.

Chrysin is mainly found in passion flowers, honey, and propolis acts as a potential therapeutic and preventive agent to inhibit proliferation and invasion of various human cancer cells. Although chrysin has anti-carcinogenic effects in several cancers, little is known about its functional roles in ovarian cancer which shows poor prognosis and chemoresistance to traditional therapeutic agents. In the present study, we investigated functional roles of chrysin in progression of ovarian cancer cells using ES2 and OV90 (clear cell and serous carcinoma, respectively) cell lines. Results of the current study demonstrated that chrysin inhibited ovarian cancer cell proliferation and induced cell death by increasing reactive oxygen species (ROS) production and cytoplasmic Ca2+ levels as well as inducing loss of mitochondrial membrane potential (MMP). Moreover, chrysin activated mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K)/AKT pathways in ES2 and OV90 cells in concentration-response experiments. Collectively, our results led us to propose that chrysin-induced apoptotic events are mediated by the activation of PI3K and MAPK pathways in human ovarian cancer cells.

Engineering of extracellular vesicles as drug delivery vehicles.

Extracellular vesicles (EVs) are secreted membrane-enclosed nano-sized particles (40-1,000 nm) that deliver biological information between cells. The molecular composition of these subcellular particles includes growth factor receptors, ligands adhesion proteins, mRNA, miRNAs, lncRNA and lipids that are derived from donor cells. A number of studies demonstrated that stem cell-derived EVs are the key mediator of tissue repair and regeneration in multiple animal disease models. In addition, the composition of these particles is known to be altered in cancer and disease pathology suggesting them for useful in diagnostic and therapeutic purposes. Their endogenous origin and biological properties offer benefits over conventional drug delivery systems (DDS), such as liposome, synthetic nanoparticles and prompted the further application of EVs as drug delivery vehicles for chemical drugs, genetic materials and proteins. The contents of EVs can be efficiently modified by chemical, biological or physical means. Thus, EVs can be an innovative DDS as it can overcome physical and biological barriers and safely deliver therapeutic drugs to target tissues. In this minireview, we summarized current progress on the strategies of drug loading onto EVs; ex vivo and in vivo loading.

MicroRNA-761 inhibits Angiotensin II-induced vascular smooth muscle cell proliferation and migration by targeting mammalian target of rapamycin.

Aberrant vascular smooth muscle cell (VSMC) proliferation and migration are a major pathological phenomenon in vascular disease characterized by intimal thickening. The important role of the mammalian target of rapamycin (mTOR) signaling in VSMC proliferation has been previously reported. Consequently, down-regulation of mTOR pathway may be an effective way of controlling excessive VSMC proliferation. Since microRNAs (miRNA) are newly emerging regulators of virtually all the biological processes including cellular proliferation, miRNAs targeting mTOR pathway may be utilized to suppress aberrant VSMC proliferation during pathologic conditions. Thus, in the present study, we screened miRNAs targeting mTOR, and we identified miR-761 as a new mTOR targeting miRNA. Luciferase assay using luciferase vector containing 3'UTR of mTOR indicated that miR-761 directly targets mTOR mRNA leading to suppression of mTOR protein expression. Our data also indicate that miR-761 expression decreases during angiotensin II (AngII)-induced proliferation of VSMCs, and exogenous miR-761 delivery effectively inhibit the AngII-induced VSMC proliferation. Additionally, the results of migration tests demonstrate that down-regulation of mTOR using exogenous miR-761 suppresses AngII-induced migration of VSMCs as well. Taken together, the present study provided evidence that miR-761 can be a potent anti-proliferative agent for vascular diseases such as atherosclerosis and restenosis, and warrants further studies to validate the effectiveness of miR-761 in vivo.

MicroRNAs as mediators of cardiovascular disease: Targets to be manipulated.

Cardiovascular disease has been the leading cause of death worldwide for the last few decades. Even with the rapid progression of the biomedical field, conquering/managing cardiovascular disease is not an easy task because it is multifactorial disease. One of the key players of the development and progression of numerous diseases is microRNA (miRNA). These small, non-coding RNAs bind to target mRNAs to inhibit translations of and/or degrade the target mRNAs, thus acting as negative regulators of gene expressions. Accumulating evidence indicates that non-physiological expressions of miRNAs contribute to both development and progression of cardiovascular diseases. Since even a single miRNA can have multiple targets, dysregulation of miRNAs can lead to catastrophic changes of proteins that may be important for maintaining physiologic conditions of cells, tissues, and organs. Current knowledge on the role of miRNAs in cardiovascular disease is mostly based on the observational data such as microarray of miRNAs in animal disease models, thus relatively lacking insight of how such dysregulation of miRNAs is initiated and regulated. Consequently, future research should aim to elucidate the more comprehensive mechanisms of miRNA dysregulation during pathogenesis of the cardiovascular system so that appropriate counter-measures to prevent/manage cardiovascular disease can be developed.

Na(+)-Ca(2+) exchanger targeting miR-132 prevents apoptosis of cardiomyocytes under hypoxic condition by suppressing Ca(2+) overload.

During ischemia-reperfusion (IR) injury of the heart, Ca(2+) overload occurs, leading to cardiomyocyte dysfunction and eventual cell death by apoptosis. Since preventing Ca(2+) overload during IR injury has been reported to protect cardiomyocytes, interrupting Ca(2+) signaling cascades leading to Ca(2+) overload may exert protective effect on cardiomyocytes under hypoxic condition. One of the key regulators of the intracellular Ca(2+) level during IR injury is Na(+)-Ca(2+) exchanger 1 (NCX1), whose down-regulation during IR injury conferred protection of heart. In the present study, we examined whether down-regulation of NCX1 using exogenous microRNA ameliorates apoptosis of cardiomyocytes under hypoxic condition. Here, we identified miR-132 as a novel microRNA targeting the NCX1, whose expression increased during hypoxia. Delivery of miR-132 suppressed the increase of intracellular Ca(2+) in cardiomyocytes under hypoxia, and the expressions of apoptotic molecules, such as Bax, cytochrome C, and caspase 3, and the number of apoptotic cells were also decreased by exogenous miR-132 treatment. These results suggest the potential of miR-132 as an effective therapeutic agent against IR damage to heart by preventing Ca(2+) overload during hypoxic condition and warrant further studies to validate its anti-apoptotic effect in vivo.

Co-Culture of α TC-6 Cells and ß TC-1 Cells: Morphology and Function.

BACKGROUND: In vitro experiments using only ß-cell lines instead of islets are limited because pancreatic islets are composed of four different types of endocrine cells. Several recent studies have focused on cellular interactions among these cell types, especially α- and ß-cells. Because islet isolation needs time and experience, we tested a simple co-culture system with α- and ß-cells. Their morphology and function were assessed by comparison to each single cell culture and pancreatic islets. METHODS: α TC-6 cells and ß TC-1 cells were maintained in Dulbecco's Minimal Essential Medium containing 5 mM glucose and 10% fetal bovine serum. Cells were mixed at a 1:1 ratio (5×105) in 6-well plates and cultured for 24, 48, and 72 hours. After culture, cells were used for insulin and glucagon immunoassays and tested for glucose-stimulated insulin secretion (GSIS). RESULTS: α TC-6 and ß TC-1 cells became condensed by 24 hours and were more strongly compacted after 48 hours. ß TC-1 cells showed both ß-ß and ß-α cell contacts. GSIS increased with increasing glucose concentration in co-cultured cells, which showed lower secreted insulin levels than ß TC-1 cells alone. The increase in the secreted insulin/insulin content ratio was significantly lower for co-cultured cells than for ß-cells alone (P=0.04). Compared to islets, the α-/ß-cell co-culture showed a higher ratio of GSIS to insulin content, but the difference was not statistically significant (P=0.09). CONCLUSION: α TC-6 and ß TC-1 cells in the co-culture system showed cell-to-cell contacts and a similar stimulated insulin secretion pattern to islets. The co-culture system may be used to better mimic pancreatic islets in in vitro assessments.

Effect of the TiN content in the Pd-TiN seed layer on the microstructure and magnetic properties of Co∕Pd multilayered media.

[Co(0.2 nm)∕Pd(0.8 nm)](20) multilayered films on 15 nm Pd-TiN seed layers were fabricated by dc magnetron sputtering without heating the substrate. The effects of TiN content on microstructure and magnetic properties of the [Co∕Pd] multilayered media were studied. By increasing the TiN content in the Pd-TiN seed layer to an optimum level, coercivity of the [Co∕Pd] multilayered media increased to 6.7 kOe. However, further increase of TiN content beyond 22 vol % reduced coercivity (Hc), implying that there exists a critical TiN concentration to enhance the magnetic property of the [Co∕Pd] multilayered media. Transmission electron microscopic observations revealed that well-isolated [Co∕Pd] multilayered grains with apparent grain boundaries were achieved by controlling the TiN content in the Pd-TiN seed layer. The average grain diameter was 8 nm with a dispersion of 11.2%, grown on the Pd-TiN seed layer with TiN content of 22 vol %.

Two-year outcomes of the sirolimus-eluting stent according to unprotected left main lesion.

BACKGROUND: The data of long-term outcomes of sirolimus-eluting stent (SES) according to lesion location of unprotected left main coronary artery (LMCA) is scarce. HYPOTHESIS: The purpose of this study was to evaluate the long-term outcomes after implantation of the SES in LMCA. METHODS: A total of 84 patients (51 males) who had undergone SES implantation for the treatment of native LMCA stenosis were enrolled. The patients were divided into 2 groups based on angiographic lesion location: those with significant stenosis in the ostium and/or body (group 1; n = 39) and those involving bifurcation (group 2; n = 45). RESULTS: All of the group 1 patients were treated with simple lesion coverage while different stenting techniques were used in group 2 (cross-over: 44.8%, T: 6.7%, kissing: 37.8%, and crush techniques: 11.1%). The 8-month quantitative angiographic findings and in-hospital and 2 year rates of major adverse cardiac events (MACE) were compared between the 2 groups. Although angiographic success and in-hospital MACE rates were similar in both groups with 1 cardiac death due to acute stent thrombosis in group 2, at 2-year follow-up, the MACE rate was significantly higher in group 2 than in group 1 at 2 years (22.2% vs 2.6%, respectively, P = 0.008). Coronary angiography revealed a significantly higher binary restenosis rate in group 2 compared with group 1 (20% vs 0%, respectively, P = 0.003). CONCLUSIONS: Interventional treatment using SES in left main lesions showed favorable short-term and long-term outcomes in selected patients with lesion location being an important determinant of clinical and angiographic outcomes.