Publications by authors named "Kyu Sung Choi"

24 Publications

  • Page 1 of 1

A deep learning model for diagnosing gastric mucosal lesions using endoscopic images: development, validation, and method comparison.

Gastrointest Endosc 2021 Sep 4. Epub 2021 Sep 4.

Department of Internal Medicine and Liver Research Institute, Seoul National University College of Medicine, Seoul, Korea. Electronic address:

Background And Aims: Endoscopic differential diagnoses of gastric mucosal lesions (benign gastric ulcer, early gastric cancer [EGC], and advanced gastric cancer) remain challenging. We aimed to develop and validate convolutional neural network-based artificial intelligence (AI) models: lesion detection (AI-LD), differential diagnosis (AI-DDx), and invasion-depth (AI-ID, pT1a vs. pT1b among EGC) models.

Methods: This study included 1,366 consecutive patients with gastric mucosal lesions from 2 referral centers in Korea. One representative endoscopic image from each patient was used. Histological diagnoses were set as the criterion standard. The performances of the AI-DDx (training/internal/external validation set, n=1009/112/245) and AI-ID (training/internal/external validation set, n=620/68/155) were compared with visual diagnoses by independent endoscopists (stratified by novice [<1 year of experience], intermediate [2-3 years of experience], and expert [>5 years of experience]) and endoscopic ultrasonography (EUS) results, respectively.

Results: The AI-DDx showed good diagnostic performance for both internal (area under of the receiver operating characteristic curve [AUROC]=0.86) and external validation (AUROC=0.86). The performance of the AI-DDx was better than that of the novice (AUROC=0.82, P=0.01) and intermediate endoscopists (AUROC=0.84, P=0.02), but was comparable to the experts (AUROC=0.89, P=0.12) in the external validation set. The AI-ID showed fair performances in both internal (AUROC=0.78) and external validation sets (AUROC=0.73), which were significantly better than EUS results performed by experts (internal validation: AUROC=0.62, external validation: AUROC=0.56; both P <0.001).

Conclusion: The AI-DDx was comparable with experts and outperformed novice and intermediate endoscopists for the differential diagnosis of gastric mucosal lesion. The AI-ID performed better than EUS for the invasion-depth evaluation (https://aiscopeseoul.com/).
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.gie.2021.08.022DOI Listing
September 2021

Deep Learning for Detection of Pulmonary Metastasis on Chest Radiographs.

Radiology 2021 Aug 31:210578. Epub 2021 Aug 31.

From the Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea (E.J.H., J.S.L., J.H.L., W.H.L., J.H.K., K.S.C., T.W.C., T.H.K., J.M.G., C.M.P.); Department of Radiology, Namwon Medical Center, Namwon, Korea (W.H.L.); Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea (K.S.C.); and Department of Radiology, Naval Pohang Hospital, Pohang, Korea (T.H.K.).

Background A computer-aided detection (CAD) system may help surveillance for pulmonary metastasis at chest radiography in situations where there is limited access to CT. Purpose To evaluate whether a deep learning (DL)-based CAD system can improve diagnostic yield for newly visible lung metastasis on chest radiographs in patients with cancer. Materials and Methods A regulatory-approved CAD system for lung nodules was implemented to interpret chest radiographs from patients referred by the medical oncology department in clinical practice. In this retrospective diagnostic cohort study, chest radiographs interpreted with assistance from a CAD system after the implementation (January to April 2019, CAD-assisted interpretation group) and those interpreted before the implementation (September to December 2018, conventional interpretation group) of the CAD system were consecutively included. The diagnostic yield (frequency of true-positive detections) and false-referral rate (frequency of false-positive detections) of formal reports of chest radiographs for newly visible lung metastasis were compared between the two groups using generalized estimating equations. Propensity score matching was performed between the two groups for age, sex, and primary cancer. Results A total of 2916 chest radiographs from 1521 patients (1546 men, 1370 women; mean age, 62 years) and 5681 chest radiographs from 3456 patients (2941 men, 2740 women; mean age, 62 years) were analyzed in the CAD-assisted interpretation and conventional interpretation groups, respectively. The diagnostic yield for newly visible metastasis was higher in the CAD-assisted interpretation group (0.86%, 25 of 2916 [95% CI: 0.58, 1.3] vs 0.32%, 18 of 568 [95% CI: 0.20, 0.50%]; 004). The false-referral rate in the CAD-assisted interpretation group (0.34%, 10 of 2916 [95% CI: 0.19, 0.64]) was not inferior to that in the conventional interpretation group (0.25%, 14 of 5681 [95% CI: 0.15, 0.42]) at the noninferiority margin of 0.5% (95% CI of difference: -0.15, 0.35). Conclusion A deep learning-based computer-aided detection system improved the diagnostic yield for newly visible metastasis on chest radiographs in patients with cancer with a similar false-referral rate. © RSNA, 2021
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1148/radiol.2021210578DOI Listing
August 2021

Deep Learning for Detection of Pulmonary Metastasis on Chest Radiographs.

Radiology 2021 Aug 31:210578. Epub 2021 Aug 31.

From the Department of Radiology, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul 03080, Korea (E.J.H., J.S.L., J.H.L., W.H.L., J.H.K., K.S.C., T.W.C., T.H.K., J.M.G., C.M.P.); Department of Radiology, Namwon Medical Center, Namwon, Korea (W.H.L.); Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology, Daejeon, Korea (K.S.C.); and Department of Radiology, Naval Pohang Hospital, Pohang, Korea (T.H.K.).

Background A computer-aided detection (CAD) system may help surveillance for pulmonary metastasis at chest radiography in situations where there is limited access to CT. Purpose To evaluate whether a deep learning (DL)-based CAD system can improve diagnostic yield for newly visible lung metastasis on chest radiographs in patients with cancer. Materials and Methods A regulatory-approved CAD system for lung nodules was implemented to interpret chest radiographs from patients referred by the medical oncology department in clinical practice. In this retrospective diagnostic cohort study, chest radiographs interpreted with assistance from a CAD system after the implementation (January to April 2019, CAD-assisted interpretation group) and those interpreted before the implementation (September to December 2018, conventional interpretation group) of the CAD system were consecutively included. The diagnostic yield (frequency of true-positive detections) and false-referral rate (frequency of false-positive detections) of formal reports of chest radiographs for newly visible lung metastasis were compared between the two groups using generalized estimating equations. Propensity score matching was performed between the two groups for age, sex, and primary cancer. Results A total of 2916 chest radiographs from 1521 patients (1546 men, 1370 women; mean age, 62 years) and 5681 chest radiographs from 3456 patients (2941 men, 2740 women; mean age, 62 years) were analyzed in the CAD-assisted interpretation and conventional interpretation groups, respectively. The diagnostic yield for newly visible metastasis was higher in the CAD-assisted interpretation group (0.86%, 25 of 2916 [95% CI: 0.58, 1.3] vs 0.32%, 18 of 568 [95% CI: 0.20, 0.50%]; 004). The false-referral rate in the CAD-assisted interpretation group (0.34%, 10 of 2916 [95% CI: 0.19, 0.64]) was not inferior to that in the conventional interpretation group (0.25%, 14 of 5681 [95% CI: 0.15, 0.42]) at the noninferiority margin of 0.5% (95% CI of difference: -0.15, 0.35). Conclusion A deep learning-based computer-aided detection system improved the diagnostic yield for newly visible metastasis on chest radiographs in patients with cancer with a similar false-referral rate. © RSNA, 2021
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1148/radiol.2021210578DOI Listing
August 2021

Prediction of Prognosis in Glioblastoma Using Radiomics Features of Dynamic Contrast-Enhanced MRI.

Korean J Radiol 2021 Sep 14;22(9):1514-1524. Epub 2021 Jul 14.

Department of Radiology, Seoul National University Hospital, Seoul, Korea.

Objective: To develop a radiomics risk score based on dynamic contrast-enhanced (DCE) MRI for prognosis prediction in patients with glioblastoma.

Materials And Methods: One hundred and fifty patients (92 male [61.3%]; mean age ± standard deviation, 60.5 ± 13.5 years) with glioblastoma who underwent preoperative MRI were enrolled in the study. Six hundred and forty-two radiomic features were extracted from volume transfer constant (K), fractional volume of vascular plasma space (V), and fractional volume of extravascular extracellular space (V) maps of DCE MRI, wherein the regions of interest were based on both T1-weighted contrast-enhancing areas and non-enhancing T2 hyperintense areas. Using feature selection algorithms, salient radiomic features were selected from the 642 features. Next, a radiomics risk score was developed using a weighted combination of the selected features in the discovery set (n = 105); the risk score was validated in the validation set (n = 45) by investigating the difference in prognosis between the "radiomics risk score" groups. Finally, multivariable Cox regression analysis for progression-free survival was performed using the radiomics risk score and clinical variables as covariates.

Results: 16 radiomic features obtained from non-enhancing T2 hyperintense areas were selected among the 642 features identified. The radiomics risk score was used to stratify high- and low-risk groups in both the discovery and validation sets (both < 0.001 by the log-rank test). The radiomics risk score and presence of isocitrate dehydrogenase (IDH) mutation showed independent associations with progression-free survival in opposite directions (hazard ratio, 3.56; = 0.004 and hazard ratio, 0.34; = 0.022, respectively).

Conclusion: We developed and validated the "radiomics risk score" from the features of DCE MRI based on non-enhancing T2 hyperintense areas for risk stratification of patients with glioblastoma. It was associated with progression-free survival independently of IDH mutation status.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3348/kjr.2020.1433DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8390822PMC
September 2021

Radiomics-based neural network predicts recurrence patterns in glioblastoma using dynamic susceptibility contrast-enhanced MRI.

Sci Rep 2021 May 11;11(1):9974. Epub 2021 May 11.

Seoul National University College of Medicine, Seoul, Republic of Korea.

Glioblastoma remains the most devastating brain tumor despite optimal treatment, because of the high rate of recurrence. Distant recurrence has distinct genomic alterations compared to local recurrence, which requires different treatment planning both in clinical practice and trials. To date, perfusion-weighted MRI has revealed that perfusional characteristics of tumor are associated with prognosis. However, not much research has focused on recurrence patterns in glioblastoma: namely, local and distant recurrence. Here, we propose two different neural network models to predict the recurrence patterns in glioblastoma that utilizes high-dimensional radiomic profiles based on perfusion MRI: area under the curve (AUC) (95% confidence interval), 0.969 (0.903-1.000) for local recurrence; 0.864 (0.726-0.976) for distant recurrence for each patient in the validation set. This creates an opportunity to provide personalized medicine in contrast to studies investigating only group differences. Moreover, interpretable deep learning identified that salient radiomic features for each recurrence pattern are related to perfusional intratumoral heterogeneity. We also demonstrated that the combined salient radiomic features, or "radiomic risk score", increased risk of recurrence/progression (hazard ratio, 1.61; p = 0.03) in multivariate Cox regression on progression-free survival.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/s41598-021-89218-zDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8113258PMC
May 2021

Absolute quantification of tumor-infiltrating immune cells in high-grade glioma identifies prognostic and radiomics values.

Cancer Immunol Immunother 2021 Jul 8;70(7):1995-2008. Epub 2021 Jan 8.

Department of Neurosurgery, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Korea.

Purpose: To understand the tumor immune microenvironment precisely, it is important to secure the quantified data of tumor-infiltrating immune cells, since the immune cells are true working unit. We analyzed unit immune cell number per unit volume of core tumor tissue of high-grade gliomas (HGG) to correlate their immune microenvironment characteristics with clinical prognosis and radiomic signatures.

Methods: The number of tumor-infiltrating immune cells from 64 HGG core tissue were analyzed using flow cytometry and standardized. After sorting out patient groups according to diverse immune characteristics, the groups were tested if they have any clinical prognostic relevance and specific radiomic signature relationships. Sparse partial least square with discriminant analysis using multimodal magnetic resonance images was employed for all radiomic classifications.

Results: The median number of CD45 + cells per one gram of HGG core tissue counted 865,770 cells which was equivalent to 8.0% of total cells including tumor cells. There was heterogeneity in the distribution of immune cell subpopulations among patients. Overall survival was significantly better in T cell-deficient group than T cell-enriched group (p = 0.019), and T8 dominant group than T4 dominant group (p = 0.023). The number of tumor-associated macrophages (TAM) and M2-TAM was significantly decreased in isocitrate dehydrogenase mutated HGG. Radiomic signature classification showed good performance in predicting immune phenotypes especially with features extracted from apparent diffusion coefficient maps.

Conclusions: Absolute quantification of tumor-infiltrating immune cells confirmed the heterogeneity of immune microenvironment in HGG which harbors prognostic impact. This immune microenvironment could be predicted by radiomic signatures non-invasively.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00262-020-02836-wDOI Listing
July 2021

Improving the Reliability of Pharmacokinetic Parameters at Dynamic Contrast-enhanced MRI in Astrocytomas: A Deep Learning Approach.

Radiology 2020 10 4;297(1):178-188. Epub 2020 Aug 4.

From the Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Republic of Korea (K.S.C., B.J.); Department of Radiology, Korea University College of Medicine, Anam Hospital, Seoul, Republic of Korea (S.H.Y.); Bio Imaging and Signal Processing Laboratory, Department of Bio and Brain Engineering, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Republic of Korea (Y.H., J.C.Y.); Department of Radiology, Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Republic of Korea (S.H.C.); Department of Radiology, Seoul National University College of Medicine, Seoul, Republic of Korea (S.H.C.); Center for Nanoparticle Research, Institute for Basic Science (IBS), Seoul, Republic of Korea (S.H.C.); KAIST Institute for Health Science and Technology, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Republic of Korea (B.J.); and KAIST Institute for Artificial Intelligence, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Republic of Korea (B.J.).

Background Pharmacokinetic (PK) parameters obtained from dynamic contrast agent-enhanced (DCE) MRI evaluates the microcirculation permeability of astrocytomas, but the unreliability from arterial input function (AIF) remains a challenge. Purpose To develop a deep learning model that improves the reliability of AIF for DCE MRI and to validate the reliability and diagnostic performance of PK parameters by using improved AIF in grading astrocytomas. Materials and Methods This retrospective study included 386 patients (mean age, 52 years ± 16 [standard deviation]; 226 men) with astrocytomas diagnosed with histopathologic analysis who underwent dynamic susceptibility contrast (DSC)-enhanced and DCE MRI preoperatively from April 2010 to January 2018. The AIF was obtained from each sequence: AIF obtained from DSC-enhanced MRI (AIF) and AIF measured at DCE MRI (AIF). The model was trained to translate AIF into AIF, and after training, outputted neural-network-generated AIF (AIF) with input AIF. By using the three different AIFs, volume transfer constant (), fractional volume of extravascular extracellular space (V), and vascular plasma space (V) were averaged from the tumor areas in the DCE MRI. To validate the model, intraclass correlation coefficients and areas under the receiver operating characteristic curve (AUCs) of the PK parameters in grading astrocytomas were compared by using different AIFs. Results The AIF-generated, DSC-derived PK parameters showed higher AUCs in grading astrocytomas than those derived from AIF (mean , 0.88 [95% confidence interval {CI}: 0.81, 0.93] vs 0.72 [95% CI: 0.63, 0.79], = .04; mean V, 0.87 [95% CI: 0.79, 0.92] vs 0.70 [95% CI: 0.61, 0.77], = .049, respectively). and V showed higher intraclass correlation coefficients for AIF than for AIF (0.91 vs 0.38, < .001; and 0.86 vs 0.60, < .001, respectively). In AIF analysis, baseline signal intensity (SI), maximal SI, and wash-in slope showed higher intraclass correlation coefficients with AIF than AIF (0.77 vs 0.29, < .001; 0.68 vs 0.42, = .003; and 0.66 vs 0.45, = .01, respectively. Conclusion A deep learning algorithm improved both reliability and diagnostic performance of MRI pharmacokinetic parameters for differentiating astrocytoma grades. © RSNA, 2020
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1148/radiol.2020192763DOI Listing
October 2020

Reproducibility of calcium scoring of the coronary arteries: comparison between different vendors and iterative reconstructions.

Acta Radiol Open 2020 Apr 28;9(4):2058460120922147. Epub 2020 Apr 28.

Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.

Background: The coronary artery calcium scoring (CCS) has been widely used for cardiac risk stratification for asymptomatic patients.

Purpose: To assess the reproducibility of CCS performed on four different computed tomography (CT) scanners, and compare the variability between two reconstruction algorithms, filtered back projection (FBP), and iterative reconstruction (IR).

Material And Methods: A CCS phantom was made from agar and contained 23 pieces of chicken bones. The phantom was repeatedly scanned using four different CT scanners: Toshiba; GE; Philips; and Siemens. Images were reconstructed using FBP and IR. Agatston and volume scores of total bone fragments were calculated and the overall differences between the instruments were evaluated using the Friedman test. Comparison of the Agatston and volume scores between the two reconstruction algorithms, for each instrument, was evaluated using the Wilcoxon signed rank test.

Results: The difference in the Agatston scores was significantly different between the four machines ( = 0.001). The Toshiba scanner yielded the highest score followed by Philips, GE, and Siemens scanners. There was no difference in the CCS evaluated using the two reconstruction algorithms, except in case of the Siemens scanner ( = 0.032).

Conclusion: CCS performed on different scanners varied significantly. In the Toshiba, Philips, and GE scanners, there was no significant difference in the CCS determined using either an IR or the FBP algorithm. In the Siemens scanner, applying the IR algorithm resulted in a slightly different scores, which might not be clinically significant.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/2058460120922147DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7218275PMC
April 2020

Application of T1-weighted BLADE sequence to abdominal magnetic resonance imaging of young children: a comparison with turbo spin echo sequence.

Acta Radiol 2020 Oct 24;61(10):1406-1413. Epub 2020 Jan 24.

Department of Radiology, Seoul National University Hospital, Seoul, Republic of Korea.

Background: The image quality of abdominal magnetic resonance imaging (MRI) in children who cannot hold their breath has been severely impaired by motion artifacts.

Purpose: To evaluate the usefulness of T1-weighted (T1W) BLADE MRI for axial abdominal imaging in children who cannot hold their breath.

Material And Methods: Two different BLADE sequences, with and without an inversion recovery (IR-BLADE), were compared to conventional turbo-spin echo (TSE) with a high number of excitations in 18 consecutive patients who cannot hold their breath. Overall image quality, motion artifact, radial artifact, hepatic vessel sharpness, renal corticomedullary differentiation, and lesion conspicuity were retrospectively assessed by two radiologists, using 4- or 5-point scoring systems. Signal variations of each sequence were measured for a quantitative comparison. The acquisition times of the three sequences were compared.

Results: IR-BLADE and BLADE showed significantly improved overall image quality and reduced motion artifact compared with TSE. IR-BLADE showed significantly better hepatic vessel sharpness and corticomedullary differentiation compared to both BLADE and TSE. Radial artifacts were only observed on IR-BLADE and BLADE. In nine patients with lesions, there were no significant differences in lesion conspicuity among three sequences. Compared to TSE, both IR-BLADE and BLADE showed decreased signal variations in the liver and muscle, and an increased signal variation through air. The mean acquisition times for IR-BLADE, BLADE, and TSE were comparable.

Conclusion: Compared to the TSE sequence, T1W IR-BLADE for pediatric abdominal MRI resulted in improved image quality, tissue contrast with a diminished respiratory motion artifact, and a comparable acquisition time.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0284185120901512DOI Listing
October 2020

Glucose Transport and Transporters in the Endomembranes.

Int J Mol Sci 2019 Nov 24;20(23). Epub 2019 Nov 24.

Institute of Translational Medicine, Semmelweis University, 1094 Budapest, Hungary.

Glucose is a basic nutrient in most of the creatures; its transport through biological membranes is an absolute requirement of life. This role is fulfilled by glucose transporters, mediating the transport of glucose by facilitated diffusion or by secondary active transport. GLUT (glucose transporter) or SLC2A (Solute carrier 2A) families represent the main glucose transporters in mammalian cells, originally described as plasma membrane transporters. Glucose transport through intracellular membranes has not been elucidated yet; however, glucose is formed in the lumen of various organelles. The glucose-6-phosphatase system catalyzing the last common step of gluconeogenesis and glycogenolysis generates glucose within the lumen of the endoplasmic reticulum. Posttranslational processing of the oligosaccharide moiety of glycoproteins also results in intraluminal glucose formation in the endoplasmic reticulum (ER) and Golgi. Autophagic degradation of polysaccharides, glycoproteins, and glycolipids leads to glucose accumulation in lysosomes. Despite the obvious necessity, the mechanism of glucose transport and the molecular nature of mediating proteins in the endomembranes have been hardly elucidated for the last few years. However, recent studies revealed the intracellular localization and functional features of some glucose transporters; the aim of the present paper was to summarize the collected knowledge.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3390/ijms20235898DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6929180PMC
November 2019

Prediction of IDH genotype in gliomas with dynamic susceptibility contrast perfusion MR imaging using an explainable recurrent neural network.

Neuro Oncol 2019 09;21(9):1197-1209

Graduate School of Medical Science and Engineering, Korea Advanced Institute for Science and Technology (KAIST), Daejeon, Republic of Korea.

Background: The aim of this study was to predict isocitrate dehydrogenase (IDH) genotypes of gliomas using an interpretable deep learning application for dynamic susceptibility contrast (DSC) perfusion MRI.

Methods: Four hundred sixty-three patients with gliomas who underwent preoperative MRI were enrolled in the study. All the patients had immunohistopathologic diagnoses of either IDH-wildtype or IDH-mutant gliomas. Tumor subregions were segmented using a convolutional neural network followed by manual correction. DSC perfusion MRI was performed to obtain T2* susceptibility signal intensity-time curves from each subregion of the tumors: enhancing tumor, non-enhancing tumor, peritumoral edema, and whole tumor. These, with arterial input functions, were fed into a neural network as multidimensional inputs. A convolutional long short-term memory model with an attention mechanism was developed to predict IDH genotypes. Receiver operating characteristics analysis was performed to evaluate the model.

Results: The IDH genotype predictions had an accuracy, sensitivity, and specificity of 92.8%, 92.6%, and 93.1%, respectively, in the validation set (area under the curve [AUC], 0.98; 95% confidence interval [CI], 0.969-0.991) and 91.7%, 92.1%, and 91.5%, respectively, in the test set (AUC, 0.95; 95% CI, 0.898-0.982). In temporal feature analysis, T2* susceptibility signal intensity-time curves obtained from DSC perfusion MRI with attention weights demonstrated high attention on the combination of the end of the pre-contrast baseline, up/downslopes of signal drops, and/or post-bolus plateaus for the curves used to predict IDH genotype.

Conclusions: We developed an explainable recurrent neural network model based on DSC perfusion MRI to predict IDH genotypes in gliomas.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/neuonc/noz095DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7594560PMC
September 2019

Integrative analysis of DNA methylation and mRNA expression during differentiation of umbilical cord blood derived mononuclear cells to endothelial cells.

Gene 2017 Nov 6;635:48-60. Epub 2017 Sep 6.

Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea. Electronic address:

Differentiation of umbilical cord blood derived mononuclear cells to endothelial cells is accompanied by massive changes in gene expression. Although methylation and demethylation of DNA likely play crucial roles in regulating gene expression, their interplay during differentiation remains elusive. To address this question, we performed deep sequencing of DNA methylation and mRNA expression to profile global changes in promoter methylation and gene expression during differentiation from mononuclear cells to outgrowing cells. We identified 61 downregulated genes with hypermethylation, including CD74, VAV1, TLR8, and NCF4, as well as 21 upregulated genes with hypomethylation, including ECSCR, MCAM, PGF, and ARHGEF15. Interestingly, gene ontology analysis showed that downregulated genes with hypermethylation were enriched in immune-related functions, and upregulated genes with hypomethylation were enriched in the developmental process and angiogenesis, indicating the important roles of DNA methylation in regulating differentiation. We performed polymerase chain reaction analyses and bisulfite sequencing of representative genes (CD74, VAV1, ECSCR, and MCAM) to verify the negative correlation between DNA methylation and gene expression. Further, inhibition of DNA methyltransferase and demethylase activities using 5'-aza-dc and shRNAs, specific for TET1 and TET2 mRNAs, respectively, revealed that DNA methylation was the main regulator of the reversible expression of functionally important genes. Collectively, our findings implicate DNA methylation as a critical regulator of gene expression during umbilical cord blood derived mononuclear cells to endothelial cell differentiation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.gene.2017.09.006DOI Listing
November 2017

Sac-1004, a vascular leakage blocker, reduces cerebral ischemia-reperfusion injury by suppressing blood-brain barrier disruption and inflammation.

J Neuroinflammation 2017 06 23;14(1):122. Epub 2017 Jun 23.

Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul, 120-749, South Korea.

Background: Blood-brain barrier (BBB) breakdown and inflammation are critical events in ischemic stroke, contributing to aggravated brain damage. The BBB mainly consists of microvascular endothelial cells sealed by tight junctions to protect the brain from blood-borne substances. Thus, the maintenance of BBB integrity may be a potential target for neuroprotection. Sac-1004, a pseudo-sugar derivative of cholesterol, enhances the endothelial barrier by the stabilization of the cortical actin ring.

Results: Here, we report on the protective effects of Sac-1004 on cerebral ischemia-reperfusion (I/R) injury. Treatment with Sac-1004 significantly blocked the interleukin-1β-induced monolayer hyperpermeability of human brain microvascular endothelial cells (HBMECs), loss of tight junctions, and formation of actin stress fiber. Sac-1004 suppressed the expression of adhesion molecules, adhesion of U937 cells, and activation of nuclear factor-κB in HBMECs. Using a rat model of transient focal cerebral ischemia, it was shown that Sac-1004 effectively ameliorated neurological deficits and ischemic damage. In addition, Sac-1004 decreased BBB leakage and rescued tight junction-related proteins. Moreover, the staining of CD11b and glial fibrillary acidic protein showed that Sac-1004 inhibited glial activation.

Conclusions: Taken together, these results demonstrate that Sac-1004 has neuroprotective activities through maintaining BBB integrity, suggesting that it is a great therapeutic candidate for stroke.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1186/s12974-017-0897-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5481915PMC
June 2017

Extremely Small Pseudoparamagnetic Iron Oxide Nanoparticle as a Novel Blood Pool T1 Magnetic Resonance Contrast Agent for 3 T Whole-Heart Coronary Angiography in Canines: Comparison With Gadoterate Meglumine.

Invest Radiol 2017 02;52(2):128-133

From the *Department of Radiology and the Institute of Radiation Medicine, Seoul National University Hospital; †Department of Radiology, Seoul National University Boramae Hospital; ‡Department of Nuclear Medicine, Seoul National University College of Medicine; §Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, and College of Medicine or College of Pharmacy, Seoul National University, Seoul; and ∥Research and Development Center, Hanwha Chemical Corp, Daejeon, Yuseong-gu, South Korea.

Objective: The aim of this study was to evaluate an extremely small pseudoparamagnetic iron oxide nanoparticle (ESPIO), KEG3, as a potential blood pool agent in 3 T coronary magnetic resonance angiography (MRA) in canine models and compare its efficacy to that of a gadolinium-based contrast agent.

Materials And Methods: Nine mongrel dogs were subjected to whole-heart coronary MRA in 2 separate sessions at 7-day intervals with a 3 T scanner using the FLASH sequence with either gadoterate meglumine (Gd-DOTA) or the ESPIO (KEG3). Coronary MRA was performed twice at each MR examination: the first scan during the administration of the contrast agent and the subsequent second scan at 15 minutes after contrast injection. Objective measurements of the Gd-DOTA and ESPIO images, including the signal-to-noise ratios (SNRs) for the coronary arteries and cardiac veins, contrast-to-noise ratios (CNRs) between the vessels and fat (CNRfat) and the vessels and the myocardium (CNRmyocardium), and subjective image quality scores on a 4-point scale were evaluated and compared.

Results: The mean SNRs and CNRs of all vascular regions in the ESPIO images were similar to those of the corresponding regions in the Gd-DOTA images in the first scan (98.1 ± 32.5 vs 79.1 ± 38.4 for SNR of coronary arteries, P = 0.3; 74.2 ± 30.1 vs 61.4 ± 38.5 for CNR, P = 0.7) and more than 2 times higher than the latter in the second scan (95.2 ± 31.3 vs 32.1 ± 8.1 for SNR of coronary arteries, P = 0.008; 76.1 ± 35.8 vs 17.6 ± 19.2 for CNR, P 0.008). Similarly, the mean values of the subjective measurements of the ESPIO images were similar to those of the Gd-DOTA images (3.9 ± 0.3 vs 3.3 ± 0.8 for coronary arteries, P = 0.1) in the first scan and significantly better than the latter in the second scan (3.9 ± 0.2 vs 2.1 ± 0.6 for coronary arteries, P = 0.007).

Conclusions: The experimental blood pool agent KEG3 offers equivalent image quality for whole-heart coronary MRA at 3 T upon contrast administration and persistent better quality in the subsequent scans, compared with a traditional extracellular gadolinium-based contrast agent.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/RLI.0000000000000321DOI Listing
February 2017

Early Gastric Cancers: Is CT Surveillance Necessary after Curative Endoscopic Submucosal Resection for Cancers That Meet the Expanded Criteria?

Radiology 2016 Nov 25;281(2):444-453. Epub 2016 May 25.

From the Departments of Radiology (K.S.C., S.H.K., J.K.H.) and Internal Medicine (S.G.K.), Seoul National University Hospital, 101 Daehangno, Jongno-gu, Seoul 110-744, Korea; Department of Radiology, Seoul National University College of Medicine, Seoul, Korea (S.H.K., J.K.H.); and Institute of Radiation Medicine, Seoul National University Medical Research Center, Seoul, Korea (J.K.H.).

Purpose To determine the yield of follow-up abdominopelvic computed tomography (CT) in detecting extragastric recurrence after curative endoscopic submucosal dissection (ESD) for early gastric cancers (EGCs) that meet the expanded criteria. Materials and Methods Institutional review board approval was obtained for this retrospective study, and the requirement to obtain informed consent was waived. Patients who underwent curative ESD for EGCs that met the expanded criteria between November 2005 and December 2009 and who underwent post-ESD CT and endoscopy were included. The final cohort comprised 415 EGCs in 404 patients (261 EGCs in 251 patients met the conventional criteria, and 154 EGCs in 153 patients met the expanded criteria). The primary outcome was post-ESD CT discovery of extragastric recurrence (ie, lymph node or distant metastasis) not detected with endoscopy. The mean radiation dose from each CT examination was calculated. The incidence of gastric recurrence detected with endoscopy and/or CT was also analyzed. The cumulative incidence of gastric recurrence during the post-ESD follow-up period was analyzed with the Kaplan-Meier method. Results From a total of 2182 post-ESD CT examinations, extragastric recurrence (lymph node metastasis) was detected in only two patients (one with EGC that met conventional criteria and one with EGC that met expanded criteria). The mean (±standard deviation) volume CT dose index, dose-length product, and size-specific dose estimate per CT examination was 28.95 mGy ± 8.44, 876.80 mGy · cm ± 161.86, and 43.78 mGy ± 11.54, respectively. From a total of 3262 post-ESD endoscopic examinations, 41 gastric recurrences were detected (11 local recurrences and five synchronous and 25 metachronous gastric cancers). Among them, eight gastric recurrences were also detected with CT. The cumulative incidences of gastric recurrence 1, 3, and 5 years after ESD were 1.7% (two of 404 patients), 3.2% (13 of 404 patients), and 7.4% (30 of 404 patients), respectively. Conclusion When EGC meets the expanded criteria, surveillance CT after curative ESD rarely depicts extragastric recurrence during 5-year post-ESD follow-up. RSNA, 2016 Online supplemental material is available for this article.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1148/radiol.2016152866DOI Listing
November 2016

Intestinal malrotation in patients with situs anomaly: Implication of the relative positions of the superior mesenteric artery and vein.

Eur J Radiol 2016 Oct 20;85(10):1695-1700. Epub 2016 Jul 20.

Department of Radiology, Seoul National University Hospital, Republic of Korea; Department of Radiology, Seoul National University College of Medicine, Republic of Korea; Institute of Radiation Medicine, Seoul National University Medical Research Center, Republic of Korea.

Purpose: To assess the usefulness of the relative position of the superior mesenteric artery (SMA) and superior mesenteric vein (SMV) in diagnosing intestinal malrotation in situs anomaly.

Materials And Methods: From January 2004 to April 2015, 33 patients with situs anomalies were enrolled in this study who underwent abdominal USG, CT or MRI as well as upper gastrointestinal series (UGIS) or surgery: situs inversus (n=16), left isomerism (n=10), and right isomerism (n=7); age 21.2±23.2years (mean±standard deviation), range 0-72 years. The intestinal malrotation was confirmed with UGIS and/or operation in 16 patients. Relative positions of the SMV to the SMA were classified into four groups by reviewing abdominal USG, CT, or MRI: right sided, left sided, ventral sided, and dorsal sided. The incidence of malrotation was analyzed for each group.

Results: In 16 patients with situs inversus, there was reversed SMA-SMV relationship: left sided (n=11) or ventral sided (n=5). One situs inversus patient with ventral sided SMV had intestinal malrotation (6.25%). 17 patients with situs ambiguus showed various SMA-SMV relationships (ventral sided, n=7; left sided, n=5; right sided, n=4; dorsal sided, n=1). Among them, 15 patients (88.2%) had intestinal malrotation. Two patients with normal rotation had either right sided or dorsal sided SMV.

Conclusion: Situs ambiguus was commonly associated with intestinal malrotation with a variable SMA-SMV relationship. Reversal of the mesenteric vascular relationship was observed in situs inversus with normal rotation, not excluding the possibility of intestinal malrotation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ejrad.2016.07.013DOI Listing
October 2016

The endothelial E3 ligase HECW2 promotes endothelial cell junctions by increasing AMOTL1 protein stability via K63-linked ubiquitination.

Cell Signal 2016 11 4;28(11):1642-51. Epub 2016 Aug 4.

Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 03722, Republic of Korea. Electronic address:

Cell-to-cell junctions are critical for the formation of endothelial barriers, and its disorganization is required for sprouting angiogenesis. Members of the angiomotin (AMOT) family have emerged as key regulators in the control of endothelial cell (EC) junction stability and permeability. However, the underlying mechanism by which the AMOT family is regulated in ECs remains unclear. Here we report that HECW2, a novel EC ubiquitin E3 ligase, plays a critical role in stabilizing endothelial cell-to-cell junctions by regulating AMOT-like 1 (AMOTL1) stability. HECW2 physically interacts with AMOTL1 and enhances its stability via lysine 63-linked ubiquitination. HECW2 depletion in human ECs decreases AMOTL1 stability, loosening the cell-to-cell junctions and altering subcellular localization of yes-associated protein (YAP) from cytoplasm into the nucleus. Knockdown of HECW2 also results in increased angiogenic sprouting, and this effect is blocked by depletion of ANG-2, a potential target of YAP. These results demonstrate that HECW2 is a novel regulator of angiogenesis and provide new insights into the mechanisms coordinating junction stability and angiogenic activation in ECs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.cellsig.2016.07.015DOI Listing
November 2016

Long-term results of oncoplastic breast surgery with latissimus dorsi flap reconstruction: a pilot study of the objective cosmetic results and patient reported outcome.

Ann Surg Treat Res 2016 Mar 26;90(3):117-23. Epub 2016 Feb 26.

Department of Surgery, Soonchunhyang University Bucheon Hospital, Bucheon, Korea.

Purpose: The goal of oncoplastic breast surgery is to restore the appearance of the breast and improve patient satisfaction. Thus, the assessment of cosmetic results and patient-reported outcomes (PROs) using appropriately constructed and validated instruments is essential. The aim of the present study was to assess the long-term objective cosmetic results and corresponding PROs after oncoplastic breast surgery.

Methods: Cosmetic results were assessed by the patients, a medical panel, and a computer program (BCCT.core). PROs were assessed using BREAST-Q, a questionnaire that measures the perception of patients having breast surgery. The cosmetic results and PROs were analyzed in patients who underwent quadrantectomy and partial breast reconstruction utilizing the latissimus dorsi flap.

Results: The mean duration of the follow-up period was 91.6 months (range, 33.3-171.0 months), and mean age of the patients was 51 years old (range, 33-72 years). The mean tumor size was 2.1 cm (range, 0.9-5.5 cm). There was fair agreement between the medical panel and BCCT.core score (K = 0.32, P < 0.001), and a statistically significant correlation between the BCCT.core score and medical panel cosmetic results was identified (r = 0.606, P < 0.001). A better BCCT.core result was related to a higher PRO of each BREAST-Q domain-satisfaction with breasts (R(2) = 0.070, P = 0.039), satisfaction with outcome (R(2) = 0.087, P = 0.021), psychosocial well-being (R(2) = 0.085, P = 0.023), sexual well-being (R(2) = 0.082, P = 0.029), and satisfaction with information (R(2) = 0.064, P = 0.049).

Conclusion: Our long-term results of oncoplastic surgery achieved a high level of patient satisfaction with good cosmetic results. The medical panel and BCCT.core results correlated well with the PROs of the patients using valid, reliable, and procedure-specific measures.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4174/astr.2016.90.3.117DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4773455PMC
March 2016

Evaluation of Perihilar Biliary Strictures: Does DWI Provide Additional Value to Conventional MRI?

AJR Am J Roentgenol 2015 Oct 23;205(4):789-96. Epub 2015 Jul 23.

1 Department of Radiology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul 110-744, Korea.

Objective: The purpose of this study is to evaluate whether DWI provides additional value to conventional MRI with MRCP (MRI-MRCP) in the characterization of perihilar biliary strictures and in the evaluation of the longitudinal extent of perihilar cholangiocarcinomas.

Materials And Methods: One hundred fourteen patients with perihilar strictures (81 malignant and 33 benign) underwent gadobutrol-enhanced MRI-MRCP and DWI using 10 b values (0-1000 s/mm(2)). Two readers independently reviewed a conventional set of MRI-MRCP images and a combined set of MRI-MRCP and DW images and scored the likelihoods of malignancy for perihilar strictures and involvement of the bilateral secondary confluence in malignant cases on a 5-point scale. The diagnostic performance of the two imaging sets was compared using ROC analysis.

Results: In the characterization of 114 perihilar strictures, the addition of DWI showed no statistically significant improvement in diagnostic performance (reader 1, area under the ROC curve (Az) = 0.947 vs 0.923; reader 2, Az = 0.930 vs 0.905; all p > 0.05) with an interobserver agreement of κ = 0.763-0.818. In determining bilateral secondary confluence involvement for the 81 surgically confirmed malignant strictures, the conventional and combined sets showed no statistically significant difference in diagnostic performance (reader 1, Az = 0.820 vs 0.868; reader 2, Az = 0.826 vs 0.829; all p > 0.05), with κ = 0.564-0.588.

Conclusion: The addition of DWI to conventional MRI-MRCP did not improve diagnostic performance in the characterization of perihilar strictures or in determining whether the bilateral secondary biliary confluence was involved in perihilar cholangiocarcinomas.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.2214/AJR.14.14089DOI Listing
October 2015

Percutaneous Aspiration Embolectomy Using Guiding Catheter for the Superior Mesenteric Artery Embolism.

Korean J Radiol 2015 Jul-Aug;16(4):736-43. Epub 2015 Jul 1.

Department of Radiology, Seoul National University College of Medicine, Institute of Radiation Medicine, Seoul National University Medical Research Center, and Clinical Research Institute, Seoul National University Hospital, Seoul 110-744, Korea.

Objective: To evaluate the technical feasibility and clinical outcome of percutaneous aspiration embolectomy for embolic occlusion of the superior mesenteric artery (SMA).

Materials And Methods: Between January 2010 and December 2013, 9 patients with embolic occlusion of the SMA were treated by percutaneous aspiration embolectomy in 2 academic teaching hospitals. The aspiration embolectomy procedure was performed with the 6-Fr and 7-Fr guiding catheter. Thrombolysis was performed with urokinase using a multiple-sidehole infusion catheter. The clinical outcome was investigated retrospectively.

Results: Superior mesenteric artery occlusion was initially diagnosed by computed tomography (CT) in all patients, and all patients had no obvious evidence of bowel infarction on CT scan. Percutaneous aspiration embolectomy was primarily performed in 6 patients, and thrombolysis was initially performed in 3 patients. In 3 patients who received primary thrombolysis, percutaneous aspiration was undertaken because the emboli were resistant to urokinase. Complete angiographic success was achieved in 6 patients and partial angiographic success was accomplished in 3 patients. One patient underwent bowel resection. One patient died of whole bowel necrosis and sepsis, and 8 patients survived without complications.

Conclusion: Percutaneous aspiration embolectomy is a useful tool in recanalization of embolic occlusion of the SMA in select patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3348/kjr.2015.16.4.736DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4499537PMC
February 2016

Yes-associated protein regulates endothelial cell contact-mediated expression of angiopoietin-2.

Nat Commun 2015 May 12;6:6943. Epub 2015 May 12.

Department of Biochemistry, College of Life Science and Biotechnology, Yonsei University, Seoul 120-749, Republic of Korea.

Angiogenesis is regulated by the dynamic interaction between endothelial cells (ECs). Hippo-Yes-associated protein (YAP) signalling has emerged as a key pathway that controls organ size and tissue growth by mediating cell contact inhibition. However, the role of YAP in EC has not been defined yet. Here, we show expression of YAP in the developing front of mouse retinal vessels. YAP subcellular localization, phosphorylation and activity are regulated by VE-cadherin-mediated-EC contacts. This VE-cadherin-dependent YAP phosphorylation requires phosphoinositide 3-kinase-Akt activation. We further identify angiopoietin-2 (ANG-2) as a potential transcriptional target of YAP in regulating angiogenic activity of EC in vitro and in vivo. Overexpression of YAP-active form in EC enhances angiogenic sprouting, and this effect is blocked by ANG-2 depletion or soluble Tie-2 treatment. These findings implicate YAP as a critical regulator in angiogenesis and provide new insights into the mechanism coordinating junctional stability and angiogenic activation of ECs.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1038/ncomms7943DOI Listing
May 2015

Feasibility and outcomes of laparoscopic enucleation for pancreatic neoplasms.

Ann Surg Treat Res 2014 Dec 28;87(6):285-9. Epub 2014 Nov 28.

Department of Surgery, Soonchunhyang University Bucheon Hospital, Soonchunhyang University College of Medicine, Bucheon, Korea.

Purpose: With the advancement of laparoscopic techniques and instruments, laparoscopic approach for pancreatic lesions has become an increasingly used procedure. But, there are few and limited studies about laparoscopic enuleation (LE) for pancreatic lesions. Therefore, the purpose of this study was to present our experience and to evaluate the clinical outcome of LE for pancreatic benign or borderline malignant tumors.

Methods: Between May 2005 and December 2011, 11 patients who underwent LE were analyzed. Candidates for LE met the following criteria: benign or borderline malignant pancreatic tumor, no involvement of main pancreatic duct, and outwardly growing tumor with small tumor bed.

Results: All 11 patients (10 women and 1 man with a mean age of 43.1 ± 11.9 years) who underwent LE were completed laparoscopically without conversion. The mean diameter of tumor was 4.0 ± 3.3 cm and all cases had benign tumors at the final pathologic diagnosis. One patient (9%) developed pancreatic fistula and mean postoperative hospital stay was 5.5 ± 1.7 days. During follow-up period (mean, 44.3 ± 23.9 months), all patients were alive with no recurrence or new onset of diabetes.

Conclusion: LE is a safe and effective procedure, and should be considered as a treatment option for pancreatic lesions that do not involve the main pancratic duct and have an outgrowing aspect with small tumor bed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.4174/astr.2014.87.6.285DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4255549PMC
December 2014

TIS21(/BTG2/PC3) accelerates the repair of DNA double strand breaks by enhancing Mre11 methylation and blocking damage signal transfer to the Chk2(T68)-p53(S20) pathway.

DNA Repair (Amst) 2012 Dec 22;11(12):965-75. Epub 2012 Oct 22.

Department of Biochemistry and Molecular Biology, Brain Korea 21 Division of Cell Transformation and Restoration, Ajou University, School of Medicine, Suwon 443-721, Republic of Korea.

DNA double strand breaks (DSBs) occur more frequently in TIS21(-/-) mouse embryo fibroblasts than that in wild type MEFs (wt-MEFs). Therefore, the role TIS21 plays in the DNA damage response was investigated. Adenoviral transduction of Huh7 tumor cells with the TIS21 gene accelerated the repair of DSBs induced by etoposide treatment as evaluated by clearance of γH2AX foci and the Comet assay. TIS21 increased methylation of Mre11 and protein arginine methyltransferase 1 (PRMT1) activity, leading to Mre11 activation in vitro and in vivo, as determined by immunoprecipitation and radiolabeling analyses. When downstream DNA damage response mediators were evaluated in various human cancer cells lines, TIS21 was found to strongly inhibit Chk2(T68) and p53(S20) phosphorylation by p-ATM(S1981) but not p53(S15). The loss of Chk2 activation after etoposide treatment reduced apoptosis in the cells by downregulating the expression of E2F1 and Bax. These data suggest that TIS21 regulates DSB repair and apoptosis. Expression of TIS21 promoted the repair of DSBs and reduced apoptosis by blocking the damage signal from p-ATM(S1981) to Chk2(T68)-p53(S20)via the activation of Mre11 and PRMT1.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.dnarep.2012.09.009DOI Listing
December 2012

Comparative study on the toxic effects of red tide flagellates Heterocapsa circularisquama and Chattonella marina on the short-necked clam (Ruditapes philippinarum).

Biosci Biotechnol Biochem 2011 7;75(10):2052-5. Epub 2011 Oct 7.

Jeju Center, Korea Basic Science Institute (KBSI), Jeju-Si, Jeju Special Self-Governing Province, Korea.

Heterocapsa circularisquama showed much higher toxic effects on short-necked clams than Chattonella marina. Clams exposed to H. circularisquama exhibited morphological changes concomitant with an accumulation of mucus-like substances in the gills, a profound reduction in filtration activity, and lysosomal destabilization in hemocytes. Chattonella marina was less effective than H. circularisquama, and Heterocapsa triquetra was almost harmless in all these criteria. These results suggest that H. circularisquama exerted its lethal effect on short-necked clams through gill tissue damage and subsequent induction of physiological stress.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1271/bbb.110382DOI Listing
February 2012
-->