Ki Hak Song

Dr. Ki Hak Song


Research Focus & Metrics

Academic Career Length

16Years (2011-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 July 2020 in BMC Urology
Verified
Journal Article
Open access
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SYSeung Woo Yang
Seung Woo Yang
YHYun Kyung Hyon
Yun Kyung Hyon
HNHyun Seok Na
Hyun Seok Na
LJLong Jin
Long Jin
JLJae Geun Lee
Jae Geun Lee
KSKi Hak Song
Ki Hak Song
The aims of this study were to determine the predictive value of decision support analysis for the shock wave lithotripsy (SWL) success rate and to analyze the data obtained from patients who underwent SWL to assess the factors influencing the outcome by using machine learning methods. We retrospectively reviewed the medical records of 358 patients who underwent SWL for urinary stone (kidney and upper-ureter stone) between 2015 and 2018 and evaluated the possible prognostic features, including patient population characteristics, urinary stone characteristics on a non-contrast, computed tomographic image. We performed 80% training set and 20% test set for the predictions of success and mainly used decision tree-based machine learning algorithms, such as random forest (RF), extreme gradient boosting trees (XGBoost), and light gradient boosting method (LightGBM). In machine learning analysis, the prediction accuracies for stone-free were 86.0, 87.5, and 87.9%, and those for one-session success were 78.0, 77.4, and 77.0% using RF, XGBoost, and LightGBM, respectively. In predictions for stone-free, LightGBM yielded the best accuracy and RF yielded the best one in those for one-session success among those methods. The sensitivity and specificity values for machine learning analytics are (0.74 to 0.78 and 0.92 to 0.93) for stone-free and (0.79 to 0.81 and 0.74 to 0.75) for one-session success, respectively. The area under curve (AUC) values for machine learning analytics are (0.84 to 0.85) for stone-free and (0.77 to 0.78) for one-session success and their 95% confidence intervals (CIs) are (0.730 to 0.933) and (0.673 to 0.866) in average of methods, respectively. We applied a selected machine learning analysis to predict the result after treatment of SWL for urinary stone. About 88% accurate machine learning based predictive model was evaluated. The importance of machine learning algorithm can give matched insights to domain knowledge on effective and influential factors for SWL success outcomes.

1 February 2013 in BMC Cancer
Verified
Journal Article
Open access
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HCHong Chung
Hong Chung
BKBokyung Kim
Bokyung Kim
SJSeung-Hyo Jung
Seung-Hyo Jung
KWKyung Jong Won
Kyung Jong Won
XJXiaowen Jiang
Xiaowen Jiang
HKHong Sup Kim
Hong Sup Kim
Background: We determined the differently expressed protein profiles and their functions in bladder cancer tissues with the aim of identifying possible target proteins and underlying molecular mechanisms for taking part in their progression. Methods: We examined the expression of proteins by proteomic analysis and western blot in normal urothelium, non-muscle-invasive bladder cancers (NMIBCs), and muscle-invasive bladder cancers (MIBCs). The function of cofilin was analyzed using T24 human bladder cancer cells. Results: The expression levels of 12 proteins were altered between bladder cancers and normal bladder tissues. Of these proteins, 14-3-3σ was upregulated in both NMIBCs and MIBCs compared with controls. On the other hand, myosin regulatory light chain 2, galectin-1, lipid-binding AI, annexin V, transthyretin, CARD-inhibitor of NF-κB-activating ligand, and actin prepeptide were downregulated in cancer samples. Cofilin, an actin-depolymerizing factor, was prominent in both NMIBCs and MIBCs compared with normal bladder tissues. Furthermore, we confirmed that cofilin phosphorylation was more prominent in MIBCs than in NMIBCs using immunoblotting and immunohistochemcal analyses. Epidermal growth factor (EGF) increased the phosphorylation of cofilin and elevated the migration in T24 cells. Knockdown of cofilin expression with small interfering RNA attenuated the T24 cell migration in response to EGF. Conclusions: These results demonstrate that the increased expression and phosphorylation of cofilin might play a role in the occurrence and invasiveness of bladder cancer. We suspected that changes in cofilin expression may participate in the progression of the bladder cancer.

27 June 2019 in Clinical and Experimental Pharmacology and Physiology
Verified
Journal Article
Closed access
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TJTae Woo Jung
Tae Woo Jung
SASung Ho Ahn
Sung Ho Ahn
JSJong Wook Shin
Jong Wook Shin
HKHyoung-Chun Kim
Hyoung-Chun Kim
EPEon Sub Park
Eon Sub Park
JJJi Hoon Jeong
Ji Hoon Jeong

28 April 2021 in BMC Cancer
Verified
Journal Article
Open access
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JLJaegeun Lee
Jaegeun Lee
SYSeung Woo Yang
Seung Woo Yang
LJLong Jin
Long Jin
CLChung Lyul Lee
Chung Lyul Lee
JLJi Yong Lee
Ji Yong Lee
KSKi Hak Song
Ki Hak Song
Background: Serum prostate-specific antigen (PSA) is widely used in screening tests for prostate cancer. As the low specificity of PSA results in unnecessary and invasive prostate biopsies, we evaluated the clinical significance of various PSAs and PSA density (PSAD) related to peripheral zones in patients with gray zone PSA level (4–10 ng/mL). Methods: A total of 1300 patients underwent transrectal ultrasonography-guided prostate biopsy from 2014 to 2019. Among them, 545 patients in the gray zone were divided into the prostate cancer diagnosis group and the non-prostate cancer diagnosis group, and PSA, relative extra transitional zone PSA (RETzPSA), estimated post holmium laser enucleation of the prostate PSA (EPHPSA), PSAD, peripheral zone PSA density (PZPSAD) and extra-transitional zone density (ETzD) were compared and analyzed using receiver-operating characteristics (ROC) analysis after 1:1 matching using propensity score. Results: Area under the ROC curve values of PSA, EPHPSA, RETzPSA, PSA density, ETzD, and PZPSAD were 0.553 (95% CI: 0.495–0.610), 0.611 (95% CI: 0.554–0.666), 0.673 (95% CI: 0.617–0.725), 0.745 (95% CI: 0.693–0.793), 0.731 (95% CI: 0.677–0.780) and 0.677 (95% CI: 0.611–0.719), respectively. PSAD had 67.11% sensitivity, 71.71% specificity, and 70.34% positive predictive rate at 0.18 ng/mL/cc. ETzD had 69.08% sensitivity, 64.47% specificity, and 66.04% positive predictive rate at 0.04 ng/mL/cc. When the cut-off value of PSAD was increased to 0.18 ng/mL/cc, the best results were obtained with an odds ratio of 5.171 (95% CI: 3.171–8.432), followed by ETzD with 4.054 (95% CI: 2.513–6.540). Conclusions: These results suggested that volume-adjusted parameters (ETzD and PSAD) might be more sensitive and accurate than various PSA in gray zone patients who required prostate biopsy to reduce unnecessary biopsy.

31 December 2021 in International Neurourology Journal
Verified
Journal Article
Open access
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JPJong Mok Park
Jong Mok Park
JSJu Hyun Shin
Ju Hyun Shin
SYSeung Woo Yang
Seung Woo Yang
JLJi Lee
Ji Lee
CLChung Lyul Lee
Chung Lyul Lee
YNYong Gil Na
Yong Gil Na
Purpose: Although metformin and sildenafil can protect various organs against ischemia/reperfusion (I/R) injuries, their effects and mechanisms of action in bladder I/R injuries remain unknown. This study investigated the effects and mechanisms of action of metformin and sildenafil against bladder I/R insults in rats.Methods: One hundred male Sprague-Dawley rats were randomly divided into 5 groups, each of which contained 20 rats: a sham-operated group, a bladder I/R group, and bladder I/R groups treated with metformin, sildenafil, or both agents. Ischemia was induced by clamping the bilateral common iliac arteries with atraumatic vascular clamps for 2 hours, followed by reperfusion for 7 days. During this period, rats were injected once daily with 4-mg/kg metformin and/or 1-mg/kg sildenafil.Results: I/R injuries induced increased malondialdehyde levels and myeloperoxidase activity and decreased superoxide dismutase activity. These changes were attenuated by treatment with metformin and/or sildenafil. The I/R group had significantly higher Jun N-terminal kinase, p38 mitogen-activated protein kinase (MAPK), Bax, caspase-3, and nuclear factor-kappa B (NF-κB) levels, and lower extracellular signal-regulated kinase, and Bcl-2 levels in the bladder than the sham-operated group; these changes were significantly ameliorated by metformin and/or sildenafil treatment. No differences in the levels of these markers were observed between rats coadministered metformin and sildenafil and those treated with either agent alone.Conclusions: Metformin and sildenafil protected the rat bladder against I/R injuries. This effect may have been due to the inhibition of reactive oxygen species production through MAPK, Bax, and Bcl-2 activation, and the restoration of inflammation through NF-κB inhibition. However, the combination of metformin and sildenafil was not more effective than either agent alone.

16 March 2022 in International Journal of Urology
Verified
Journal Article
Open access
CLChung Lyul Lee
Chung Lyul Lee
HSHyeun-Kyoo Shin
Hyeun-Kyoo Shin
JLJi Lee
Ji Lee
OKOJin Kwon
OJin Kwon
CSChangseob Seo
Changseob Seo
JSJu Hyun Shin
Ju Hyun Shin
Objectives: To evaluate the efficacy and safety of tamsulosin and Hachimijiogan or Ryutanshakanto in patients with lower urinary tract symptoms due to benign prostatic hyperplasia.Methods: A prospective, randomized, double‐blind method was used to determine the efficacy and safety of the combination or placebo at baseline and 4, 8, and 12 weeks of study. The International Prostate Symptom Score, quality of life index, complete voiding diary, and National Institutes of Health‐Chronic Prostatitis Symptom Index were studied. Uroflowmetery and postvoid residual urine volume were measured and compared. Laboratory tests including prostate‐specific antigen were performed.Results: In all groups, International Prostate Symptom Score and quality of life showed improvement, but no significant differences were shown among the groups. Prostate volume increased after treatment, and uroflowmetric parameters showed improvements after treatment without significance among the three groups. The total score of the National Institutes of Health‐Chronic Prostatitis Symptom Index showed a significant improvement in all groups, without significant differences among the groups. Only the pain sub‐score of the National Institutes of Health‐Chronic Prostatitis Symptom Index showed a significant decrease in the tamsulosin with Ryutanshakanto group compared to the control group. A total of 11 adverse reactions occurred, but they were mild and not related to the study drugs.Conclusion: Ryutanshakanto can provide pain relief in patients with chronic prostatitis and chronic pelvic pain syndrome. If more research is conducted, Hachimijiogan and Ryutanshakanto may be applied as add‐on treatments in patients with storage symptoms with alpha‐blocker monotherapy.