• Korean Journal of Radiology
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• v.20 no.1
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• pp.83-93
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• 2019

Objective: The purpose of this study was to prospectively investigate the value of the myocardial extracellular volume fraction (ECV) in predicting myocardial functional outcome after revascularization of coronary chronic total occlusion (CTO). Materials and Methods: Thirty patients with CTO underwent cardiovascular magnetic resonance (CMR) before and 6 months after revascularization. Three baseline markers of functional outcome were evaluated in the dysfunctional segments assigned to the CTO vessels: ECV, transmural extent of infarction (TEI), and unenhanced rim thickness (RIM). At the global level, the ECV values of the whole myocardium with and without a hyperenhanced region (global and remote ECV) were respectively measured. Results: In per-segment analysis, ECV was superior to TEI and RIM in predicting functional recovery (area under receiver operating characteristic curve [AUC]: 0.86 vs. 0.75 and 0.73, all p values < 0.010), and it emerged as the only independent predictor of regional functional outcome (odds ratio [OR] = 0.83, 95% confidence interval [CI]: 0.77-0.89; p < 0.001) independent of collateral circulation. In per-patient analysis, global baseline ECV was indicative of ejection fraction (EF) at the follow-up examination (β = -0.61, p < 0.001) and changes in EF (β = -0.57, p = 0.001) in multivariate regression analysis. A patient with global baseline ECV less than 30.0% (AUC, 0.93; sensitivity 94%, specificity 80%) was more likely to demonstrate significant EF improvement (OR: 0.38; 95% CI: 0.17-0.85; p = 0.019). Conclusion: Extracellular volume fraction obtained by CMR may provide incremental value for the prediction of functional recovery both at the segmental and global levels in CTO patients, and may facilitate the identification of patients who can benefit from revascularization.

• Journal of the Korean Society of Radiology
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• v.82 no.2
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• pp.429-434
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• 2021

Amyloidosis is a multisystemic disease characterized by the accumulation of abnormal proteins in extracellular spaces in various organs, with frequent involvement of the myocardium. We report a case of a patient who had cardiac amyloidosis with a trend of reduction in native T1 and T2 values and extracellular volume fraction on serial cardiac magnetic resonance imaging after chemotherapy and stem cell transplantation. The native T1 value and the extracellular volume fraction are closely associated with tissue amyloid burden in amyloidosis patients. This case demonstrated that cardiac magnetic resonance imaging may be used as a non-invasive and quantitative biomarker in the treatment monitoring of amyloidosis.

• Korean Journal of Radiology
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• v.23 no.12
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• pp.1251-1259
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• 2022

Objective: T1 mapping provides valuable information regarding cardiomyopathies. Manual drawing is time consuming and prone to subjective errors. Therefore, this study aimed to test a DL algorithm for the automated measurement of native T1 and extracellular volume (ECV) fractions in cardiac magnetic resonance (CMR) imaging with a temporally separated dataset. Materials and Methods: CMR images obtained for 95 participants (mean age ± standard deviation, 54.5 ± 15.2 years), including 36 left ventricular hypertrophy (12 hypertrophic cardiomyopathy, 12 Fabry disease, and 12 amyloidosis), 32 dilated cardiomyopathy, and 27 healthy volunteers, were included. A commercial deep learning (DL) algorithm based on 2D U-net (Myomics-T1 software, version 1.0.0) was used for the automated analysis of T1 maps. Four radiologists, as study readers, performed manual analysis. The reference standard was the consensus result of the manual analysis by two additional expert readers. The segmentation performance of the DL algorithm and the correlation and agreement between the automated measurement and the reference standard were assessed. Interobserver agreement among the four radiologists was analyzed. Results: DL successfully segmented the myocardium in 99.3% of slices in the native T1 map and 89.8% of slices in the post-T1 map with Dice similarity coefficients of 0.86 ± 0.05 and 0.74 ± 0.17, respectively. Native T1 and ECV showed strong correlation and agreement between DL and the reference: for T1, r = 0.967 (95% confidence interval [CI], 0.951-0.978) and bias of 9.5 msec (95% limits of agreement [LOA], -23.6-42.6 msec); for ECV, r = 0.987 (95% CI, 0.980-0.991) and bias of 0.7% (95% LOA, -2.8%-4.2%) on per-subject basis. Agreements between DL and each of the four radiologists were excellent (intraclass correlation coefficient [ICC] of 0.98-0.99 for both native T1 and ECV), comparable to the pairwise agreement between the radiologists (ICC of 0.97-1.00 and 0.99-1.00 for native T1 and ECV, respectively). Conclusion: The DL algorithm allowed automated T1 and ECV measurements comparable to those of radiologists.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.6
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• pp.494-499
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• 2005

The chemical, physical, and emulsifying properties of BSF-1, which is an extracellular lipopolysaccharide biosurfactant produced by Klebsiella oxytoca strain BSF-1, were studied. BSF-1 was found to be composed mainly of carbohydrate and fatty acids. The average molecular weight was $1,700{\sim}2,000 kDa$. The polysaccharide fraction contained L-rhamnose, D-galactose, D-glucose, and D-glucuronic acid at a molar ratio of 3:1: 1:1. The fatty acid content was 1.1 % (w/w) and consisted mainly of palmitic acid (C16:0), 3-hydroxylauric acid (3-OH-C12:0), and lauric acid (C12:0). In terms of thermal properties, BSF-1 was revealed to have inter- and intra-molecular hydrogen bonds. The hydrodynamic volume (intrinsic viscosity) of BSF-1 was 22.8dL/g. BSF-1 could be maintained as a stable emulsion for 48 h through a low-level reduction in surface tension. The optimal emulsification temperature was $30^{\circ}C$. Emulsification by BSF-1 was efficient at both acidic and neutral pH values.

• Korean Journal of Microbiology
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• v.39 no.3
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• pp.148-154
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• 2003

Moraxella sp. CK-l is known to inhibits the growth of Anabaena cylindrica, a cyanobacterium. It has been documented that the ability of this growth inhibition of Anabaena cylindrica was attributed to extracellular autolysin from Moraxella sp. CK-l. However, it remains to be elucidated identification and characterization of autolysin have yet been elucidated. In this study, we tried to purify and identify autolysin secreted from Moraxella sp. CK-l. Cells were grown in a complex liquid medium (BGC-11) and culture supernatants were collected, followed by ammonium sulfate fractionation. Fractions were further separated with anion exchange column, Mono-Q, in FPLC system and analyzed by SDS/PAGE. The fraction containing high autolysin activity showed a single distinct protein peak in anion column and molecular mass of about 17 kDa in SDS/PAGE. Nterminal amino acid sequencing of the protein was analyzed, of which result showed the homology with some proteases, including extracellular serine protease, Dichelobacter nodosus.

• Investigative Magnetic Resonance Imaging
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• v.20 no.2
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• pp.114-119
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• 2016

We report a case of vegetation in a 4-year-old female with infective endocarditis, diagnosed by late gadolinium-enhanced (LGE) cardiovascular magnetic resonance (CMR) imaging. The patient had a history of primary closure for ventricular septal defect and presented with mild febrile sensation. No remarkable clinical symptoms or laboratory findings were noted; however, transthoracic echocardiography demonstrated a 14 mm highly mobile homogeneous mass in the right ventricle. On LGE CMR imaging, the mass showed marginal rim enhancement, which suggested the diagnosis of vegetation rather than thrombus. The extracellular volume fraction (${\geq}42%$) of the lesion was higher than that of normal myocardium. Based on the patient's clinical history of congenital heart disease and pathologic confirmation of the lesion, a diagnosis of infective endocarditis with vegetation was made.

• YAKHAK HOEJI
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• v.41 no.2
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• pp.247-254
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• 1997

The proteinase-activated receptor (PAR-2) belongs to the family of seven transmembrane region receptors, like the thrombin receptor, it is activated by specific proteolytic clea vage of its extracellular amino terminus and a synthetic peptide (SLIGRL). The earthworm protein fraction (EPF) extracted from Lumbricus rubellus elicted dose- and endothelium-dependent relaxations in phenylephrine-contracted rat thoracic aorta, whereas heat inactivated EPF (0.5 ${\mu}g$ /ml) had no effect. In the presence of the nitric oxide synthase inhibitor NG-methyl-L-arginine (1.8 micro M), EPF (0.5 ${\mu}g$ /ml)-induced relaxations were partially inhibited. Furthermore, EPF (0.5 ${\mu}g$ /ml) dramatically caused relaxation of thrombin-desenstized rat thoracic aorta. These results indicate that EPF activates PAR-2 in vascular endothelial cell. Intravenous injection of EPF (20 mg/kg, bolus) into anesthetized rats produced a marked depressor response. EPF (0 ~ 80 ${\mu}g$ /ml, gradient) was very effective on increasing of perfusion volume in rabbit ear vessel preparations. These results imply the usefulness of EPF as a vascular smooth muscle relaxant and indicate that the activation of PAR-2 may be a mechanism of EPF on hemokinetic improvement.

• The Korean Journal of Physiology
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• v.20 no.1
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• pp.103-124
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• 1986

Since it has been suggested that atrial receptor may be involved in the mechanism of extracellular volume regulation, it was shown that the granularity of atrial cardiocytes can be changed by water and salt depletion, and that an extract of cardiac atrial tissue, when injected intravenously into anesthetized rats, was shown to cause a large and rapid increase in renal excretion of sodium. Various natriuretic peptides were isolated and synthetized, and the effects were investigated by many workers. Most studies, however, have been carried out under anesthesia and there have teen some controversies over direct effect of the factor on the renal function. Therefore, it was attempted in this study to access the effects of an atrial extract and a synthetic natriuretic factor in unanesthetized rabbits. Intrarenal arterial infusion of atrial extract caused a rapid increase of urinary volume and excretion of sodium. Glomerular filtration rate and renal plasma flow were both increased with no change in filtration fraction. The ventricular extract produced no change in urinary excretion of electrolytes, nor in renal hemodynamics. Intrarenal infusion of synthetic atrial natriuretic factor caused increases of renal excretory rate of sodium, chloride and potassium, and $FE_{Na}$. Glomerular filtration rate, renal plasma flow increased. And free water clearance also increased. Accentuated excretory function correlated well with increased glomerular filtration rate and renal plasma flow during infusion and for 10 minutes following the cessation of the infusion. Renin secretion rate decreased during constant infusion of atrial natriuretic factor. However, no correlation was found with the changes in glomerular filtration rate, renal plasma flow, or urinary excretion of sodium. These results suggest that atrial extract or atrial natriuretic factor induces changes in renal hemodynamics, as in excretion of electrolytes either indirectly through hemodynamic changes or directly by inhibiting tubular reabsorption. At the same time, renin secretory function is affected by the factor possibly through an unknown mechanism.

• Investigative Magnetic Resonance Imaging
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• v.18 no.1
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• pp.25-33
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• 2014

Purpose : To investigate whether quantitative parameters derived from Diffusion-weighted magnetic resonance imaging (DW-MRI) correlate with those of Dynamic contrast-enhanced MRI (DCE-MRI). Materials and Methods: Thirteen patients with pathologically or clinically proven bony metastasis who had undergone MRI prior to treatment were included. The voxel size was $1.367{\times}1.367{\times}5mm$. A dominant tumor was selected and the apparent diffusion coefficient (ADC) value and DCE-MRI parameters were obtained by matching voxels. DCE-MRI data were analyzed yielding estimates of $K^{trans}$ (volume transfer constant) and $v_e$. (extravascular extracellular volume fraction). Statistical analysis of ADC, $K^{trans}$, and $v_e$ value was conducted using Pearson correlation analyses. Results: Fifteen lesions in pelvic bones were evaluated. Of these, 11 showed a statistically significant correlation (P<0.05) between ADC and $K^{trans}$. The ADC and $K^{trans}$ were inversely related in 7 lesions and positively related in 4 lesions. This did not depend on the primary cancer or site of metastasis. The ADC and $v_e$ of 9 lesions correlated significantly. Of these, 4 lesions were inversely related and 5 lesions were positively related. Conclusion: Unlike our theoretic hypothesis, there was no consistent correlation between ADC values and $K^{trans}$ or between ADC values and $v_e$ in metastatic bone tumors.

• Korean Journal of Radiology
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• v.21 no.6
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• pp.707-716
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• 2020

Objective: To evaluate pharmacokinetic variables from contrast-enhancing lesions (CELs) and non-enhancing T2 high signal intensity lesions (NE-T2HSILs) on dynamic contrast-enhanced (DCE) magnetic resonance (MR) imaging for predicting progression-free survival (PFS) in glioblastoma (GBM) patients. Materials and Methods: Sixty-four GBM patients who had undergone preoperative DCE MR imaging and received standard treatment were retrospectively included. We analyzed the pharmacokinetic variables of the volume transfer constant (Ktrans) and volume fraction of extravascular extracellular space within the CEL and NE-T2HSIL of the entire tumor. Univariate and multivariate Cox regression analyses were performed using preoperative clinical characteristics, pharmacokinetic variables of DCE MR imaging, and postoperative molecular biomarkers to predict PFS. Results: The increased mean Ktrans of the CEL, increased 95th percentile Ktrans of the CELs, and absence of methylated O⁶-methylguanine-DNA methyltransferase promoter were relevant adverse variables for PFS in the univariate analysis (p = 0.041, p = 0.032, and p = 0.083, respectively). The Kaplan-Meier survival curves demonstrated that PFS was significantly shorter in patients with a mean Ktrans of the CEL > 0.068 and 95th percentile Ktrans of the CEL > 0.223 (log-rank p = 0.038 and p = 0.041, respectively). However, only mean Ktrans of the CEL was significantly associated with PFS (p = 0.024; hazard ratio, 553.08; 95% confidence interval, 2.27-134756.74) in the multivariate Cox proportional hazard analysis. None of the pharmacokinetic variables from NE-T2HSILs were significantly related to PFS. Conclusion: Among the pharmacokinetic variables extracted from CELs and NE-T2HSILs on preoperative DCE MR imaging, the mean Ktrans of CELs exhibits potential as a useful imaging predictor of PFS in GBM patients.