Biomedical subjects

Dong Ki Kim

Publications and source records attributed to Dong Ki Kim.

7 recordsLinked to original sources

PubMed2026

Development and external validation of an explainable machine learning model for predicting chronic kidney disease progression in the Korean population.

BACKGROUND: Current risk stratification models, such as the Kidney Failure Risk Equation (KFRE), exhibit variable performance across ethnic groups and fail to capture dynamic clinical trajectories. This study aimed to develop and validate a Korean-specific machine learning (ML) model for predicting chronic kidney disease (CKD) progression using an ensemble approach. METHODS: We used electronic health records from Seoul National University Hospital for model development (n = 28,209) and the Korean Genome and Epidemiology Study (KoGES) CKD cohort for external validation (n = 3,960). The primary outcome was a composite of ≥40% decline in estimated glomerular filtration rate (eGFR) or progression to end-stage renal disease within 2 years. A soft-voting ensemble of four ML algorithms (XGBoost, LightGBM, CatBoost, and Random Forest) was developed. RESULTS: The ensemble model demonstrated robust discrimination in internal validation (area under the receiver operating characteristic curve [AUROC], 0.939; 95% confidence interval [CI], 0.934-0.944), significantly exceeding the KFRE (AUROC, 0.879-0.884). External validation in the KoGES cohort showed comparable discrimination (AUROC, 0.859; 95% CI, 0.798-0.914) versus KFRE (four-variable AUROC, 0.882; 95% CI, 0.818-0.935). Shapley Additive exPlanations (SHAP) analysis identified baseline eGFR, serum creatinine, eGFR slope, albumin, and hemoglobin as key prognostic features, supporting a complementary framework using KFRE for community screening and the ML model for hospital-based risk stratification. CONCLUSION: The ensemble ML model accurately predicts short-term CKD progression in Korean patients. By incorporating longitudinal features and ensemble learning, it provides a precise alternative to Western-derived equations, particularly in tertiary care settings.

Chronic kidney failure↗

PubMed2026

Systemic Proteome Profiling to Differentiate Primary Glomerular Diseases.

KEY POINTS: Plasma proteome profiling identified distinct signatures across biopsy-proven primary glomerular disease subtypes. An elastic net model using 93 proteins classified primary glomerular disease subtypes and controls, with external validation. Integrating proteomics with machine learning yields biologically interpretable insights in primary glomerular diseases. BACKGROUND: Primary GN is a heterogeneous group of kidney disorders where understanding of their pathophysiology remains incomplete. Despite the diagnostic potential of high-throughput proteomics, constrained proteomic depth and a reliance on binary comparisons have left the feasibility of using systemic signatures to differentiate multiple GN subtypes largely unexplored. METHODS: To identify protein signatures that noninvasively differentiate major primary glomerular disease subtypes and provide mechanistic insights, we performed large-scale systemic proteome profiling of 5416 plasma proteins via Olink Explore HT in a discovery cohort ( n =147) and an external validation cohort ( n =85) of Korean participants (mean age, 41±13 years; 46% female). The study population included patients with four GN subtypes-focal segmental glomerulosclerosis, IgA nephropathy, minimal change disease, and membranous nephropathy-alongside healthy controls. We developed a machine learning (ML) model using logistic regression with elastic net regularization to classify disease groups based on proteomic profiles and evaluated its performance in the independent validation cohort. RESULTS: Plasma proteome profiles were distinct among disease subtypes, emerging as a significant source of data variation independent of conventional markers such as eGFR or proteinuria levels. The ML model performed robustly in both the discovery and validation cohorts, achieving an area under the receiver operating characteristic curve >0.8 for differentiating minimal change disease, membranous nephropathy, and IgA nephropathy. The model, even without clinical information, correctly identified 93% of minimal change disease cases (14 of 15) and 63% of IgA nephropathy cases (20 of 32), but its performance was limited for focal segmental glomerulosclerosis, with only 21% of cases (three of 14) correctly classified. Functional analysis of key proteins highlighted distinct biologic pathways, such as hemostasis in minimal change disease. CONCLUSIONS: We identified distinct systemic proteome signatures for primary glomerular diseases, where disease subtype served as a major determinant of proteomic variance alongside conventional clinical markers. ML models demonstrated robust discriminatory performance for minimal change disease, membranous nephropathy, and IgA nephropathy, underscoring the potential for proteome-based classification.

Humans↗

PubMed2006

Anti-apoptotic function of thymosin-beta in developing chick spinal motoneurons.

Thymosin-betas (Tbetas) are water-soluble peptides abundantly present in the cytoplasm and extracellular compartment. The functions of Tbetas appear to be pleiotrophic, including actin-remodeling, wound healing, angiogenesis, etc. In the present study, we present the evidence that Tbetas have anti-apoptotic activity on developing chick motoneurons (MNs) in vivo. Using in ovo electroporation, we introduced three isoforms of Tbeta (Tbeta4, Tbeta10, and Tbeta15) and found the significantly diminished normal and limb bud removal (LBR)-induced programmed cell death. Such anti-apoptotic activity is independent of Tbeta's actin remodeling activity. On the other hand, overexpression of Tbetas substantially reduced early cell death initiation signal, such as phosphorylation of c-Jun. Collectively, these results suggest that Tbetas may prevent apoptosis of neurons via blockade of early apoptogenic signals independent of actin remodeling action.

Actins↗

PubMed2006

[Natural history of HBeAg negative chronic hepatitis B virus infection: a cohort study].

BACKGROUND/AIMS: The long-term virologic and biochemical changes in patients with HBeAg negative HBV infection, especially in Asia, remain unclear. To address this issue, we conducted a 3 year- retrospective, cohort study. METHODS: A total of 157 patients with HBeAg negative HBV infection who were monitored without treatment were reviewed between January 1999 and March 2004. Those patients were followed up every 3 months with liver function tests and serologic tests. All patients were stratified into 3 groups; inactive carrier (IC), viremic carrier (VC) and chronic hepatitis (CH). Serum HBV DNA was measured by a hybridization assay (sensitivity: 1.4 x 10(5)) genomes/mL, Digene Diagnostics, Silver Spring, USA). RESULTS: The median age of enrolled patients was 42.7 years (M:F=2.3:1). By single time-point observations, the 3 year-cohort prevalence of HBeAg negative CH varied from 12.7 to 35.8% (median 20.7%) HBeAg negative CH was accumulated over time (P=0.002) and transition rates among three groups after 3 years of follow-up are as follows: IC to CH, 6.0%; IC to VC, 4.1%; VC to CH, 23.2%. VC seems to be a disease state in the middle of transition from IC to CH. CONCLUSIONS: We demonstrated the dynamic changing patterns of HBeAg negative CH with time, of which the change from IC or VC to CH was dominant.

Adult↗

PubMed2004

Differential regulation of metallothionein-I and metallothionein-II mRNA expression in the rat brain following traumatic brain injury.

In this study, we investigated the expression of metallothionein (MT)-I and MT-II in the rat brain following traumatic brain injury (TBI). In the early stage, significant induction of MT-I and MT-II were observed in various regions including ventricle walls, pia mater, and dentate gyrus. At 12-24 h after TBI, strong induction of MT-I mRNA was observed in cerebral cortical layer II/III, amygdala, and piriform cortex where neurons reside. On the other hand, MT-II appeared to be expressed mainly in glial cells localized in the cerebral cortex and hippocampal formation. Three days after TBI, MTs were observed in the vimentin-positive astrocytes in the penumbra as revealed by double immunohistochemistry. The differences in expression of MT-I and MT-II in different brain regions and cell types (neuron vs. glial cells) suggests that multiple regulatory mechanisms are involved in the control of MT expression following brain injury.

Animals↗

PubMed2003

Initial dose cascade of TTS fentanyl with proper adjuvant medications in cancer pain.

According to the three step-ladder analgesics in patients with cancer pain, adjuvant drugs are required for pain relief according to the pain character and also to reduce side effects of opioids. Pain clinicians sometimes want to decide to jump directly from naive and mild opioid to transdermal therapeutic system (TTS) fentanyl with less side effects. We investigated the safety, efficacy, and satisfaction of the patients of TTS fentanyl converting from opioid-naive and mild-opioid with adjuvant drug medications in related to dose cascade of TTS fentanyl. Both opioid-naive (n=3) and opioid-using (n=34) patients started with TTS fentanyl in the lowest available delivery rate (25 microg/hr) with rescue medication. A numeric rating scale (NRS, from 0=no pain to 10=worst pain imaginable), satisfaction of the patients with the transdermal therapy and side effects were recorded everyday during 29 days. Average reductions of NRS scores were 1.79 and 2.77, and the mean doses were 35.14 and 44.12 microg/hr on the 15th and 29th day, respectively. Reported level of satisfaction with the transdermal patch and generalized pain management were 'completely satisfied' and 'satisfied'. Frequent side effects were nausea, vomiting, and constipation. In conclusion, initial application of TTS fentanyl with proper adjuvant medications is effective, safe, and well tolerated.

Administration, Cutaneous↗

PubMedDate not supplied

Changes in causative organisms and their antimicrobial susceptibilities in CAPD peritonitis: a single center's experience over one decade.

BACKGROUND: In recent years, the rate of peritonitis during continuous ambulatory peritoneal dialysis (CAPD) has been significantly reduced. However, peritonitis remains a major complication of CAPD, accounting for considerable mortality and hospitalization among CAPD patients. OBJECTIVE: To generate a "center tailored" treatment protocol for CAPD peritonitis by examining the changes of causative organisms and their susceptibilities to antimicrobial agents over the past 10 years. METHOD: Retrospective review of the medical records of 1015 CAPD patients (1108 episodes of peritonitis) who were followed up from 1992 through 2001. RESULTS: The overall incidence of peritonitis was 0.40 episodes/patient-year. The annual rate of peritonitis and the incidence of peritonitis caused by a single gram-positive organism were significantly higher in 1992 and 1993 compared with those in the rest of the years (p < 0.05). The incidence of peritonitis due to coagulase-negative staphylococcus (CoNS) decreased significantly over time, whereas there was no significant change in the incidence of Staphylococcus aureus (SA)-induced peritonitis. Among CoNS, resistance to methicillin increased from 18.4% in 1992-1993 to 41.7% in 2000-2001 (p < 0.05). In contrast, the incidence of methicillin-resistant SA was not different according to the calendar year. Catheter removal rates were significantly higher in peritonitis due to a single gram-negative organism (16.6%) compared with gram-positive peritonitis (4.8%, p < 0.005). The mortality associated with peritonitis was also higher in gram-negative (3.7%) compared with gram-positive peritonitis (1.4%), but there was no statistical significance. Among single gram-positive organism-induced peritonitis, catheter removal rates were significantly higher in SA (9.3%) than those in CoNS (2.9%, p < 0.01) and other gram-positive organisms (2.9%, p < 0.05). In peritonitis caused by CoNS, the methicillin-resistant group showed significantly higher removal rates than the methicillin-susceptible group (8.2% vs 1.0%, p < 0.01). CONCLUSION: The incidence of peritonitis for 2001 decreased to less than half that for 1992, due mainly to a significant decrease in CoNS-induced peritonitis, whereas the proportions of peritonitis due to a single gram-negative organism and methicillin-resistant CoNS increased. These findings suggest that it is necessary to prepare new center-based guidelines for the initial empirical treatment of CAPD peritonitis.

Female↗