Objective: To investigate the feasibility of using a deep learning-based analysis of auscultation... more Objective: To investigate the feasibility of using a deep learning-based analysis of auscultation data to predict significant stenosis of arteriovenous fistulas (AVF) in patients undergoing hemodialysis requiring percutaneous transluminal angioplasty (PTA). Materials and Methods: Forty patients (24 male and 16 female; median age, 62.5 years) with dysfunctional native AVF were prospectively recruited. Digital sounds from the AVF shunt were recorded using a wireless electronic stethoscope before (pre-PTA) and after PTA (post-PTA), and the audio files were subsequently converted to mel spectrograms, which were used to construct various deep convolutional neural network (DCNN) models (DenseNet201, EfficientNetB5, and ResNet50). The performance of these models for diagnosing ≥ 50% AVF stenosis was assessed and compared. The ground truth for the presence of ≥ 50% AVF stenosis was obtained using digital subtraction angiography. Gradient-weighted class activation mapping (Grad-CAM) was used to produce visual explanations for DCNN model decisions. Results: Eighty audio files were obtained from the 40 recruited patients and pooled for the study. Mel spectrograms of "pre-PTA" shunt sounds showed patterns corresponding to abnormal high-pitched bruits with systolic accentuation observed in patients with stenotic AVF. The ResNet50 and EfficientNetB5 models yielded an area under the receiver operating characteristic curve of 0.99 and 0.98, respectively, at optimized epochs for predicting ≥ 50% AVF stenosis. However, Grad-CAM heatmaps revealed that only ResNet50 highlighted areas relevant to AVF stenosis in the mel spectrogram. Conclusion: Mel spectrogram-based DCNN models, particularly ResNet50, successfully predicted the presence of significant AVF stenosis requiring PTA in this feasibility study and may potentially be used in AVF surveillance.
IntroductionEndothelial dysfunction commonly occurs in chronic kidney disease (CKD) patients and ... more IntroductionEndothelial dysfunction commonly occurs in chronic kidney disease (CKD) patients and increases the risk for cardiovascular disease. Among CKD patients, biomarkers involved in the pathogenesis of CKD-mineral bone disorder (CKD-MBD), such as phosphorus, parathyroid hormone, and fibroblast growth factor 23, are associated with endothelial dysfunction. We investigated whether these biomarkers induce endothelial dysfunction in CKD patients with normal phosphorus levels.MethodsThis cross-sectional study examined CKD patients with normal phosphorus levels; patients with an estimated glomerular filtration rate (eGFR) <15 or who were under dialysis were excluded. Iontophoresis with laser doppler flowmetry (ILDF) and peripheral arterial tonometry were performed to assess endothelial function in 85 patients. Pearson's correlation coefficient, multiple regression, and mediation analyses were performed to examine the association between CKD-MBD biomarkers and endothelial dysfu...
Background Early fluid management is considered a key element affecting mortality in critically i... more Background Early fluid management is considered a key element affecting mortality in critically ill patients requiring continuous renal replacement therapy (CRRT). Most studies have primarily focused on patients with intrinsic acute kidney injury requiring CRRT, although end-stage kidney disease (ESKD) patients generally exhibit greater vulnerability. We investigated the association between fluid balance and short-term mortality outcomes in ESKD patients undergoing chronic hemodialysis and requiring CRRT. Methods This retrospective study included 110 chronic hemodialysis patients who received CRRT between 2017 and 2019 at Ewha Womans University Mokdong Hospital. The amounts of daily input and output, and cumulative 3-day and 7-day input and output, were assessed from the initiation of CRRT. The participants were classified into two groups based on 7-day and 14-day mortalities. Cox regression analyses were carried out on the basis of the amounts of daily input and output, cumulative ...
Kaplan Kaplan–Meier event-free survival curves and comparisons between patients with and without ... more Kaplan Kaplan–Meier event-free survival curves and comparisons between patients with and without dementia by log-rank test in propensity score-matched patients (N = 756). (A) The incidence of MACCE was significantly higher in patients with dementia than those without dementia (P = 0.0304). (B) Patients without dementia showed better survival rate compared to patients with dementia (P = 0.0348). (C-E) There were no significant differences in event-free survival rates of nonfatal acute myocardial infarction, target vessel revascularization, and nonfatal hemorrhagic stroke (P = 0.31, P = 0.133, and P = 0.402, respectively). (F) However, the incidence of nonfatal ischemic stroke was significantly higher in patients with dementia than those without dementia (P = 0.0492). Abbreviations: MACCE, major adverse cardiac and cerebrovascular event. (TIF 476 kb)
Results of the Cox proportional hazards analysis for MACCE in all patients (N = 10,171). Table S2... more Results of the Cox proportional hazards analysis for MACCE in all patients (N = 10,171). Table S2. Results of the Cox proportional hazards analysis for MACCE in propensity score-matched patients (N = 756). Abbreviations: MACCE, major adverse cardiac and cerebrovascular event. (DOCX 23 kb)
Additional file 1: Figure S1. Flow diagram for patient enrollment. Table S1. Clinical parameters ... more Additional file 1: Figure S1. Flow diagram for patient enrollment. Table S1. Clinical parameters at 24-hr after initiation of continuous renal replacement therapy. Table S2. Clinical parameters at 72-hr after initiation of continuous renal replacement therapy. Table S3. Comparison of patientâ s characteristics according to amount of input or output at 24-hr and 72-hr assessment after CRRT initiation. Table S4. Power analysis to assess validity of the study sample size.
Background This study examined the effect of serum uric acid (SUA) level and urinary sodium excre... more Background This study examined the effect of serum uric acid (SUA) level and urinary sodium excretion on blood pressure as well as their combined effect on prehypertension in a Korean population. Method Data from the 7th Korea National Health and Nutrition Examination Survey for adults (≥ 19 years of age) were used. The participants were classified into two groups, normotension and prehypertension, according to the JNC-7 definition. Logistic regression was carried out and adjusted for traditionally regarded confounders of blood pressure. All analyses considered a complex sampling design. A multivariate analysis was performed on subgroups defined according to their SUA level and urinary sodium excretion. Results The 4200 participants were divided into normotension (n = 2646) and prehypertension (n = 1554) groups. In the univariate analysis, patient age, male sex, concurrent comorbidity (diabetes mellitus, cardiovascular disease, stroke, dyslipidemia, and chronic kidney disease), uric...
Background The interactive effect of cumulative input and output on achieving optimal fluid balan... more Background The interactive effect of cumulative input and output on achieving optimal fluid balance has not been well elucidated in patients with acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT). This study evaluated the interrelation of fluid components with mortality in patients with AKI requiring CRRT. Methods This is a retrospective observational study conducted with a total of 258 patients who were treated with CRRT due to AKI between 2016 and 2018 in the intensive care unit of Ewha Womans University Mokdong Hospital. The amounts of fluid input and output were assessed at 24-h and 72-h from the initiation of CRRT. The study endpoints were 7- and 28-day all-cause mortality. Results The mean patient age was 64.7 ± 15.8 years, and 165 (64.0%) patients were male. During the follow-up, 7- and 28-day mortalities were observed in 120 (46.5%) and 157 (60.9%) cases. The patients were stratified into two groups (28-day survivors vs. non-survivors), and the ...
Recent data suggested a causative role of uric acid (UA) in the development of renal disease, in ... more Recent data suggested a causative role of uric acid (UA) in the development of renal disease, in which endothelial dysfunction is regarded as the key mechanism. Endothelial-to-mesenchymal transition (EndoMT) and shedding of the glycocalyx are early changes of endothelial dysfunction. We investigated whether UA induced EndoMT in HUVECs and an animal model of hyperuricemia fed with 2% oxonic acid for 4 wk. UA induced EndoMT in HUVECs with a generation of reactive oxygen species via the activation of membranous NADPH oxidase (from 15 min) and mitochondria (from 6 h) along with glycocalyx shedding (from 6 h), which were blocked by probenecid. GM6001, an inhibitor of matrix metalloproteinase, alleviated UA-induced glycocalyx shedding and EndoMT. Antioxidants including N-acetyl cysteine, apocynin, and mitotempo ameliorated EndoMT; however, they did not change glycocalyx shedding in HUVECs. In the kidney of hyperuricemic rats, endothelial staining in peritubular capillaries (PTCs) was substantially decreased with a de novo expression of a-smooth muscle actin in PTCs. Plasma level of syndecan-1 was increased in hyperuricemic rats, which was ameliorated by allopurinol. UA caused a phenotypic transition of endothelial cells via induction of oxidative stress with glycocalyx shedding, which could be one of the mechanisms of UA-induced endothelial dysfunction and kidney disease.
Idiopathic membranous nephropathy (MN) is the most common glomerulonephritis in elderly patients ... more Idiopathic membranous nephropathy (MN) is the most common glomerulonephritis in elderly patients showing nephrotic syndrome. However, little is known about its treatment options and outcomes in elderly MN patients at long term follow-up. We retrospectively enrolled patients with biopsy-proven MN between April 1990 and December 2015 from eight tertiary hospitals in Korea. Among them, we excluded patients who had secondary causes of MN and subnephrotic-range proteinuria. We evaluated the presenting features and clinical outcomes and analyzed the all-cause mortality, renal outcomes, infection, and remission with respect to age. During the median follow-up at 77.2 months, 198 younger patients (<65 years) and 133 elderly patients (≥65 years) were enrolled. Age was an independent risk factor for all-cause mortality, renal outcome, and infection (for all P < 0.05) except remission. In elderly patients, there was no significant factor associated with mortality rate. The use of angiote...
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2002
The aim of this study is to investigate the influences of annealing temperature on initial device... more The aim of this study is to investigate the influences of annealing temperature on initial device characteristics and their correlations with ultraviolet (UV) radiation sensitivity of n-type zinc oxide/p-silicon (n-ZnO/p-Si) heterojunction photodiodes. Evolutions on the crystalline structure, surface morphology, ideality factor, barrier potential, interface state density, and donor concentration were systematically analyzed during the initial device characterizations before testing the UV sensitivities of the photonic devices. The results demonstrate that the sensitivity of each n-ZnO/p-Si photodiode annealed at various temperatures was linearly correlated with different UV illumination intensities. The devices annealed at 750 • C and 550 • C exhibit more sensitive performance than devices annealed at 150 • C and 350 • C owing to lower dark currents and good oxide quality. However, the presence of an interfacial suboxide or silicate oxide layer significantly decreased the responsivity of the photodiodes annealed at 750 • C. The maximum responsivity value was 126 mA/W for the photodiode annealed at 550 • C. It can be concluded that the photodiode annealed at 550 • C exhibits promising performance for UV sensing applications.
Hypoxia-inducible factor (HIF) is a key transcriptional factor in the response to hypoxia. Althou... more Hypoxia-inducible factor (HIF) is a key transcriptional factor in the response to hypoxia. Although the effect of HIF activation in chronic kidney disease (CKD) has been widely evaluated, the results have been inconsistent until now. This study aimed to investigate the effects of HIF-2α activation on renal fibrosis according to the activation timing in inducible tubule-specific transgenic mice with non-diabetic CKD. HIF-2α activation in renal tubular cells upregulated mRNA and protein expressions of fibronectin and type 1 collagen associated with the activation of p38 mitogen-activated protein kinase. In CKD mice, activation of HIF-2α at the beginning of CKD significantly aggravated renal fibrosis, whereas it did not lead to renal dysfunction. However, activation at a late-stage of CKD abrogated both renal dysfunction and fibrosis, which was associated with restoration of renal vasculature and amelioration of hypoxia through increased renal tubular expression of VEGF and its isoform...
Dementia is common in end-stage renal disease (ESRD) patients on hemodialysis (HD) and is associa... more Dementia is common in end-stage renal disease (ESRD) patients on hemodialysis (HD) and is associated with worse outcomes. This study aimed to investigate the risk of major adverse cardiac and cerebrovascular event (MACCE) in elderly patients with dementia initiating HD. Using the database from the Health Insurance Review & Assessment Service, we analyzed 10,171 patients aged 65 years or older who had initiated dialysis from 2005 to 2008. MACCE was defined as a composite outcome of all-cause mortality, nonfatal acute myocardial infarction, target vessel revascularization, and nonfatal ischemic and hemorrhagic stroke. The Kaplan-Meier method and Cox proportional hazards model were used, and further comparisons using propensity-score matching at 1:2 ratio were also performed. A total of 303 elderly patients (3.0%) had dementia at initiating HD. During follow-up, dementia was a significant predictor of MACCE after adjustment for confounding variables. In addition, further analyzed in th...
Background: Technique failure is an important issue for peritoneal dialysis (PD) patients. In thi... more Background: Technique failure is an important issue for peritoneal dialysis (PD) patients. In this study, we aimed to analyze technique failure rate in detail and to determine the predictors for technique failure in Korea. Methods: We identified all patients who had started dialysis between January 1, 2005, and December 31, 2008, in Korea, using the Korean Health Insurance Review and Assessment Service database. A total of 7,614 PD patients were included, and the median follow-up was 24.9 months. Results: The crude incidence rates of technique failure in PD patients were 54.1 per 1,000 patient-years. The cumulative 1-, 2-, and 3-year technique failure rates of PD patients were 4.9%, 10.3%, and 15.6%, respectively. However, those technique failure rates by KaplaneMeier analysis were overestimated compared with the values by competing risks analysis, and the differences increased with the follow-up period. In multivariate analyses, diabetes mellitus and Medical Aid as a crude reflection of low socioeconomic status were independent risk factors in both the Cox proportional hazard model and Fine and Gray subdistribution model. In addition, cancer was independently associated with a lower risk of technique failure in the Fine and Gray model. Conclusion: Technique failure was a major concern in patients initiating PD in Korea, especially in diabetic patients and Medical Aid beneficiaries. The results of our study offer a basis for risk stratification for technique failure.
Dialysis patients are at high risk for cardiovascular diseases, but until now there have been no ... more Dialysis patients are at high risk for cardiovascular diseases, but until now there have been no detailed analyses of the incidences among Asian patients initiating dialysis. The aims of this study were to determine the incidence rates of major adverse cardiac and cerebrovascular events (MACCE) and to compare them between incident HD patients and PD patients. We included all patients who had started dialysis between January 1, 2005 and December 31, 2008 in Korea, and analyzed 30,279 eligible patients [22,892 hemodialysis (HD) patients and 7387 peritoneal dialysis (PD) patients] by intention-to-treat. Median follow-up was 21.5months. The crude incidence rates were as follows: MACCE, 182 per 1000patient-years (PY); major adverse cardiac events (MACE), 138/1000PY; all-cause mortality, 116/1000PY; non-fatal acute myocardial infarction (AMI), 18/1000PY; target vessel revascularization (TVR), 17/1000PY; and non-fatal stroke, 60/1000PY. When comparing all baseline covariate-adjusted relati...
The aim of this study was to investigate whether the survival rate among Korean dialysis patients... more The aim of this study was to investigate whether the survival rate among Korean dialysis patients changed during the period between 2005 and 2008 in Korea. A total of 32357 patients who began dialysis between January 1, 2005 and December 31, 2008 were eligible for analysis. Baseline demographics, comorbidities, and mortality data were obtained from the database of the Health Insurance Review & Assessment Service. Kaplan-Meier curves according to the year of dialysis initiation showed that the survival rate was significantly different (log-rank test, p=0.005), most notably among peritoneal dialysis (PD) patients (p<0.001), although not among hemodialysis (HD) patients (p=0.497). In multivariate analysis, however, patients initiating either HD or PD in 2008 also had a significantly lower risk of mortality compared to those who began dialysis in 2005. Subgroup survival analysis among patients initiating dialysis in 2008 revealed that the survival rate of PD patients was significantl...
The causes of pyogenic liver abscess has been known as biliary tract disease or intrabadominal in... more The causes of pyogenic liver abscess has been known as biliary tract disease or intrabadominal infection but the large proportions of the patients has no apparent underlying disorders. Recently colonic mucosal lesions were reported in patients with cryptogenic liver abscess and it has been suggested that colonic mucosal break may play a role in developing liver abscess in otherwise healthy patients. We experienced a patient of severe recurrent liver abscess complicated with endophthalmitis only 3 months after successful treatment of initial cryptogenic liver abscess and a polypoid colon cancer was discovered by chance. It seems prudent to proceed colonoscopic examination in patients with cryptogenic liver abscess especially when it is recurrent. (Ewha Med J 2011;34(2):60-63
Objective: To investigate the feasibility of using a deep learning-based analysis of auscultation... more Objective: To investigate the feasibility of using a deep learning-based analysis of auscultation data to predict significant stenosis of arteriovenous fistulas (AVF) in patients undergoing hemodialysis requiring percutaneous transluminal angioplasty (PTA). Materials and Methods: Forty patients (24 male and 16 female; median age, 62.5 years) with dysfunctional native AVF were prospectively recruited. Digital sounds from the AVF shunt were recorded using a wireless electronic stethoscope before (pre-PTA) and after PTA (post-PTA), and the audio files were subsequently converted to mel spectrograms, which were used to construct various deep convolutional neural network (DCNN) models (DenseNet201, EfficientNetB5, and ResNet50). The performance of these models for diagnosing ≥ 50% AVF stenosis was assessed and compared. The ground truth for the presence of ≥ 50% AVF stenosis was obtained using digital subtraction angiography. Gradient-weighted class activation mapping (Grad-CAM) was used to produce visual explanations for DCNN model decisions. Results: Eighty audio files were obtained from the 40 recruited patients and pooled for the study. Mel spectrograms of "pre-PTA" shunt sounds showed patterns corresponding to abnormal high-pitched bruits with systolic accentuation observed in patients with stenotic AVF. The ResNet50 and EfficientNetB5 models yielded an area under the receiver operating characteristic curve of 0.99 and 0.98, respectively, at optimized epochs for predicting ≥ 50% AVF stenosis. However, Grad-CAM heatmaps revealed that only ResNet50 highlighted areas relevant to AVF stenosis in the mel spectrogram. Conclusion: Mel spectrogram-based DCNN models, particularly ResNet50, successfully predicted the presence of significant AVF stenosis requiring PTA in this feasibility study and may potentially be used in AVF surveillance.
IntroductionEndothelial dysfunction commonly occurs in chronic kidney disease (CKD) patients and ... more IntroductionEndothelial dysfunction commonly occurs in chronic kidney disease (CKD) patients and increases the risk for cardiovascular disease. Among CKD patients, biomarkers involved in the pathogenesis of CKD-mineral bone disorder (CKD-MBD), such as phosphorus, parathyroid hormone, and fibroblast growth factor 23, are associated with endothelial dysfunction. We investigated whether these biomarkers induce endothelial dysfunction in CKD patients with normal phosphorus levels.MethodsThis cross-sectional study examined CKD patients with normal phosphorus levels; patients with an estimated glomerular filtration rate (eGFR) <15 or who were under dialysis were excluded. Iontophoresis with laser doppler flowmetry (ILDF) and peripheral arterial tonometry were performed to assess endothelial function in 85 patients. Pearson's correlation coefficient, multiple regression, and mediation analyses were performed to examine the association between CKD-MBD biomarkers and endothelial dysfu...
Background Early fluid management is considered a key element affecting mortality in critically i... more Background Early fluid management is considered a key element affecting mortality in critically ill patients requiring continuous renal replacement therapy (CRRT). Most studies have primarily focused on patients with intrinsic acute kidney injury requiring CRRT, although end-stage kidney disease (ESKD) patients generally exhibit greater vulnerability. We investigated the association between fluid balance and short-term mortality outcomes in ESKD patients undergoing chronic hemodialysis and requiring CRRT. Methods This retrospective study included 110 chronic hemodialysis patients who received CRRT between 2017 and 2019 at Ewha Womans University Mokdong Hospital. The amounts of daily input and output, and cumulative 3-day and 7-day input and output, were assessed from the initiation of CRRT. The participants were classified into two groups based on 7-day and 14-day mortalities. Cox regression analyses were carried out on the basis of the amounts of daily input and output, cumulative ...
Kaplan Kaplan–Meier event-free survival curves and comparisons between patients with and without ... more Kaplan Kaplan–Meier event-free survival curves and comparisons between patients with and without dementia by log-rank test in propensity score-matched patients (N = 756). (A) The incidence of MACCE was significantly higher in patients with dementia than those without dementia (P = 0.0304). (B) Patients without dementia showed better survival rate compared to patients with dementia (P = 0.0348). (C-E) There were no significant differences in event-free survival rates of nonfatal acute myocardial infarction, target vessel revascularization, and nonfatal hemorrhagic stroke (P = 0.31, P = 0.133, and P = 0.402, respectively). (F) However, the incidence of nonfatal ischemic stroke was significantly higher in patients with dementia than those without dementia (P = 0.0492). Abbreviations: MACCE, major adverse cardiac and cerebrovascular event. (TIF 476 kb)
Results of the Cox proportional hazards analysis for MACCE in all patients (N = 10,171). Table S2... more Results of the Cox proportional hazards analysis for MACCE in all patients (N = 10,171). Table S2. Results of the Cox proportional hazards analysis for MACCE in propensity score-matched patients (N = 756). Abbreviations: MACCE, major adverse cardiac and cerebrovascular event. (DOCX 23 kb)
Additional file 1: Figure S1. Flow diagram for patient enrollment. Table S1. Clinical parameters ... more Additional file 1: Figure S1. Flow diagram for patient enrollment. Table S1. Clinical parameters at 24-hr after initiation of continuous renal replacement therapy. Table S2. Clinical parameters at 72-hr after initiation of continuous renal replacement therapy. Table S3. Comparison of patientâ s characteristics according to amount of input or output at 24-hr and 72-hr assessment after CRRT initiation. Table S4. Power analysis to assess validity of the study sample size.
Background This study examined the effect of serum uric acid (SUA) level and urinary sodium excre... more Background This study examined the effect of serum uric acid (SUA) level and urinary sodium excretion on blood pressure as well as their combined effect on prehypertension in a Korean population. Method Data from the 7th Korea National Health and Nutrition Examination Survey for adults (≥ 19 years of age) were used. The participants were classified into two groups, normotension and prehypertension, according to the JNC-7 definition. Logistic regression was carried out and adjusted for traditionally regarded confounders of blood pressure. All analyses considered a complex sampling design. A multivariate analysis was performed on subgroups defined according to their SUA level and urinary sodium excretion. Results The 4200 participants were divided into normotension (n = 2646) and prehypertension (n = 1554) groups. In the univariate analysis, patient age, male sex, concurrent comorbidity (diabetes mellitus, cardiovascular disease, stroke, dyslipidemia, and chronic kidney disease), uric...
Background The interactive effect of cumulative input and output on achieving optimal fluid balan... more Background The interactive effect of cumulative input and output on achieving optimal fluid balance has not been well elucidated in patients with acute kidney injury (AKI) requiring continuous renal replacement therapy (CRRT). This study evaluated the interrelation of fluid components with mortality in patients with AKI requiring CRRT. Methods This is a retrospective observational study conducted with a total of 258 patients who were treated with CRRT due to AKI between 2016 and 2018 in the intensive care unit of Ewha Womans University Mokdong Hospital. The amounts of fluid input and output were assessed at 24-h and 72-h from the initiation of CRRT. The study endpoints were 7- and 28-day all-cause mortality. Results The mean patient age was 64.7 ± 15.8 years, and 165 (64.0%) patients were male. During the follow-up, 7- and 28-day mortalities were observed in 120 (46.5%) and 157 (60.9%) cases. The patients were stratified into two groups (28-day survivors vs. non-survivors), and the ...
Recent data suggested a causative role of uric acid (UA) in the development of renal disease, in ... more Recent data suggested a causative role of uric acid (UA) in the development of renal disease, in which endothelial dysfunction is regarded as the key mechanism. Endothelial-to-mesenchymal transition (EndoMT) and shedding of the glycocalyx are early changes of endothelial dysfunction. We investigated whether UA induced EndoMT in HUVECs and an animal model of hyperuricemia fed with 2% oxonic acid for 4 wk. UA induced EndoMT in HUVECs with a generation of reactive oxygen species via the activation of membranous NADPH oxidase (from 15 min) and mitochondria (from 6 h) along with glycocalyx shedding (from 6 h), which were blocked by probenecid. GM6001, an inhibitor of matrix metalloproteinase, alleviated UA-induced glycocalyx shedding and EndoMT. Antioxidants including N-acetyl cysteine, apocynin, and mitotempo ameliorated EndoMT; however, they did not change glycocalyx shedding in HUVECs. In the kidney of hyperuricemic rats, endothelial staining in peritubular capillaries (PTCs) was substantially decreased with a de novo expression of a-smooth muscle actin in PTCs. Plasma level of syndecan-1 was increased in hyperuricemic rats, which was ameliorated by allopurinol. UA caused a phenotypic transition of endothelial cells via induction of oxidative stress with glycocalyx shedding, which could be one of the mechanisms of UA-induced endothelial dysfunction and kidney disease.
Idiopathic membranous nephropathy (MN) is the most common glomerulonephritis in elderly patients ... more Idiopathic membranous nephropathy (MN) is the most common glomerulonephritis in elderly patients showing nephrotic syndrome. However, little is known about its treatment options and outcomes in elderly MN patients at long term follow-up. We retrospectively enrolled patients with biopsy-proven MN between April 1990 and December 2015 from eight tertiary hospitals in Korea. Among them, we excluded patients who had secondary causes of MN and subnephrotic-range proteinuria. We evaluated the presenting features and clinical outcomes and analyzed the all-cause mortality, renal outcomes, infection, and remission with respect to age. During the median follow-up at 77.2 months, 198 younger patients (<65 years) and 133 elderly patients (≥65 years) were enrolled. Age was an independent risk factor for all-cause mortality, renal outcome, and infection (for all P < 0.05) except remission. In elderly patients, there was no significant factor associated with mortality rate. The use of angiote...
Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures, 2002
The aim of this study is to investigate the influences of annealing temperature on initial device... more The aim of this study is to investigate the influences of annealing temperature on initial device characteristics and their correlations with ultraviolet (UV) radiation sensitivity of n-type zinc oxide/p-silicon (n-ZnO/p-Si) heterojunction photodiodes. Evolutions on the crystalline structure, surface morphology, ideality factor, barrier potential, interface state density, and donor concentration were systematically analyzed during the initial device characterizations before testing the UV sensitivities of the photonic devices. The results demonstrate that the sensitivity of each n-ZnO/p-Si photodiode annealed at various temperatures was linearly correlated with different UV illumination intensities. The devices annealed at 750 • C and 550 • C exhibit more sensitive performance than devices annealed at 150 • C and 350 • C owing to lower dark currents and good oxide quality. However, the presence of an interfacial suboxide or silicate oxide layer significantly decreased the responsivity of the photodiodes annealed at 750 • C. The maximum responsivity value was 126 mA/W for the photodiode annealed at 550 • C. It can be concluded that the photodiode annealed at 550 • C exhibits promising performance for UV sensing applications.
Hypoxia-inducible factor (HIF) is a key transcriptional factor in the response to hypoxia. Althou... more Hypoxia-inducible factor (HIF) is a key transcriptional factor in the response to hypoxia. Although the effect of HIF activation in chronic kidney disease (CKD) has been widely evaluated, the results have been inconsistent until now. This study aimed to investigate the effects of HIF-2α activation on renal fibrosis according to the activation timing in inducible tubule-specific transgenic mice with non-diabetic CKD. HIF-2α activation in renal tubular cells upregulated mRNA and protein expressions of fibronectin and type 1 collagen associated with the activation of p38 mitogen-activated protein kinase. In CKD mice, activation of HIF-2α at the beginning of CKD significantly aggravated renal fibrosis, whereas it did not lead to renal dysfunction. However, activation at a late-stage of CKD abrogated both renal dysfunction and fibrosis, which was associated with restoration of renal vasculature and amelioration of hypoxia through increased renal tubular expression of VEGF and its isoform...
Dementia is common in end-stage renal disease (ESRD) patients on hemodialysis (HD) and is associa... more Dementia is common in end-stage renal disease (ESRD) patients on hemodialysis (HD) and is associated with worse outcomes. This study aimed to investigate the risk of major adverse cardiac and cerebrovascular event (MACCE) in elderly patients with dementia initiating HD. Using the database from the Health Insurance Review & Assessment Service, we analyzed 10,171 patients aged 65 years or older who had initiated dialysis from 2005 to 2008. MACCE was defined as a composite outcome of all-cause mortality, nonfatal acute myocardial infarction, target vessel revascularization, and nonfatal ischemic and hemorrhagic stroke. The Kaplan-Meier method and Cox proportional hazards model were used, and further comparisons using propensity-score matching at 1:2 ratio were also performed. A total of 303 elderly patients (3.0%) had dementia at initiating HD. During follow-up, dementia was a significant predictor of MACCE after adjustment for confounding variables. In addition, further analyzed in th...
Background: Technique failure is an important issue for peritoneal dialysis (PD) patients. In thi... more Background: Technique failure is an important issue for peritoneal dialysis (PD) patients. In this study, we aimed to analyze technique failure rate in detail and to determine the predictors for technique failure in Korea. Methods: We identified all patients who had started dialysis between January 1, 2005, and December 31, 2008, in Korea, using the Korean Health Insurance Review and Assessment Service database. A total of 7,614 PD patients were included, and the median follow-up was 24.9 months. Results: The crude incidence rates of technique failure in PD patients were 54.1 per 1,000 patient-years. The cumulative 1-, 2-, and 3-year technique failure rates of PD patients were 4.9%, 10.3%, and 15.6%, respectively. However, those technique failure rates by KaplaneMeier analysis were overestimated compared with the values by competing risks analysis, and the differences increased with the follow-up period. In multivariate analyses, diabetes mellitus and Medical Aid as a crude reflection of low socioeconomic status were independent risk factors in both the Cox proportional hazard model and Fine and Gray subdistribution model. In addition, cancer was independently associated with a lower risk of technique failure in the Fine and Gray model. Conclusion: Technique failure was a major concern in patients initiating PD in Korea, especially in diabetic patients and Medical Aid beneficiaries. The results of our study offer a basis for risk stratification for technique failure.
Dialysis patients are at high risk for cardiovascular diseases, but until now there have been no ... more Dialysis patients are at high risk for cardiovascular diseases, but until now there have been no detailed analyses of the incidences among Asian patients initiating dialysis. The aims of this study were to determine the incidence rates of major adverse cardiac and cerebrovascular events (MACCE) and to compare them between incident HD patients and PD patients. We included all patients who had started dialysis between January 1, 2005 and December 31, 2008 in Korea, and analyzed 30,279 eligible patients [22,892 hemodialysis (HD) patients and 7387 peritoneal dialysis (PD) patients] by intention-to-treat. Median follow-up was 21.5months. The crude incidence rates were as follows: MACCE, 182 per 1000patient-years (PY); major adverse cardiac events (MACE), 138/1000PY; all-cause mortality, 116/1000PY; non-fatal acute myocardial infarction (AMI), 18/1000PY; target vessel revascularization (TVR), 17/1000PY; and non-fatal stroke, 60/1000PY. When comparing all baseline covariate-adjusted relati...
The aim of this study was to investigate whether the survival rate among Korean dialysis patients... more The aim of this study was to investigate whether the survival rate among Korean dialysis patients changed during the period between 2005 and 2008 in Korea. A total of 32357 patients who began dialysis between January 1, 2005 and December 31, 2008 were eligible for analysis. Baseline demographics, comorbidities, and mortality data were obtained from the database of the Health Insurance Review & Assessment Service. Kaplan-Meier curves according to the year of dialysis initiation showed that the survival rate was significantly different (log-rank test, p=0.005), most notably among peritoneal dialysis (PD) patients (p<0.001), although not among hemodialysis (HD) patients (p=0.497). In multivariate analysis, however, patients initiating either HD or PD in 2008 also had a significantly lower risk of mortality compared to those who began dialysis in 2005. Subgroup survival analysis among patients initiating dialysis in 2008 revealed that the survival rate of PD patients was significantl...
The causes of pyogenic liver abscess has been known as biliary tract disease or intrabadominal in... more The causes of pyogenic liver abscess has been known as biliary tract disease or intrabadominal infection but the large proportions of the patients has no apparent underlying disorders. Recently colonic mucosal lesions were reported in patients with cryptogenic liver abscess and it has been suggested that colonic mucosal break may play a role in developing liver abscess in otherwise healthy patients. We experienced a patient of severe recurrent liver abscess complicated with endophthalmitis only 3 months after successful treatment of initial cryptogenic liver abscess and a polypoid colon cancer was discovered by chance. It seems prudent to proceed colonoscopic examination in patients with cryptogenic liver abscess especially when it is recurrent. (Ewha Med J 2011;34(2):60-63
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