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Determination of Noise Threshold from Signal Histogram in the Wavelet Domain
Kim, Eunseo,Lee, Kamin,Yang, Sejung,Lee, Byung-Uk The Institute of Electronics and Information Engin 2014 전자공학회논문지 Vol.51 No.2
Thresholding in frequency domain is a simple and effective noise reduction technique. Determination of the threshold is critical to the image quality. The optimal threshold minimizing the Mean Square Error (MSE) is chosen adaptively in the wavelet domain; we utilize an equation of the MSE for the soft-thresholded signal and the histogram of wavelet coefficients of the original image and noisy image. The histogram of the original signal is estimated through the deconvolution assuming that the probability density functions (pdfs) of the original signal and the noise are statistically independent. The proposed method is quite general in that it does not assume any prior for the source pdf.
Steroidogenic cytochrome P450 enzymes as drug target
Kim Changmin,Jeong Eunseo,Lee Yoo-bin,Kim Donghak 한국독성학회 2024 Toxicological Research Vol.40 No.3
Human cytochrome P450 (CYP) enzymes are composed of 57 individual enzymes that perform monooxygenase activities. They have diverse physiological roles in metabolizing xenobiotics and producing important endogenous compounds, such as steroid hormones and vitamins. At least seven CYP enzymes are involved in steroid biosynthesis. Steroidogenesis primarily occurs in the adrenal glands and gonads, connecting each reaction to substrates and products. Steroids are essential for maintaining life and significantly contribute to sexual differentiation and reproductive functions within the body. Disorders in steroid biosynthesis can frequently cause serious health problems and lead to the development of diseases, such as prostate cancer, breast cancer, and Cushing’s syndrome. In this review, we provide current updated knowledge on the major CYP enzymes involved in the biosynthetic process of steroids, with respect to their enzymatic mechanisms and clinical implications for the development of new drug candidates.
( Eunseo Lee ),( Sunghwan Yoo ),( Sukhyeon Jeong ),( In-jung Kim ),( Sora Kim ),( Hye Young Chang ),( Jung Il Lee ),( Kwan Sik Lee ),( Hyun Woong Lee ) 대한간학회 2020 춘·추계 학술대회 (KASL) Vol.2020 No.1
Aims: Some studies have shown a poor prognosis for hepatocellular carcinoma (HCC) patients whose etiology is viral. This study is to evaluate the outcomes of the patients diagnosed to resectable HCC, according to the etiology of the disease due to the differences in prognosis between viral and non-alcoholic fatty liver disease (NAFLD). Methods: A total of 264 patients who received hepatectomy for the treatment of HCC between 2005 and 2019 were performed a review of medical records. They were divided into groups according to the cause of liver disease, followed by overall and disease-free survival analysis for comparison. Results: The cause of HCC consisted of 222 hepatitis B virus (HBV) (69.4%), 14 hepatitis C virus (HCV) (4.4%), and 28 non-alcoholic steatohepatitis (NASH) (7.9%). There was no statistically significant difference in the sex, tumor stage (BCLC and AJCC 7th) of the groups of patients divided according to the etiology of HCC. However, the mean age was higher in NAFLD (NAFLD 72 years, vs. HBV 62 years, HCV 68 years, P<0.001). The presence of liver cirrhosis was lower in NAFLD (NAFLD 14.3%, vs. HBV 51.8%, HCV 50%, P=0.001). Overall survival (OS) at five years of the patients with HBV, HCV and NAFLD were 88.2%, 74.1%, and 74.6%, respectively (P=0.031). Disease-free survival at five years of patients with HBV, HCV and NAFLD were 72.5%, 69.3%, and 77.9%, respectively (P=0.370). In multivariate analysis, age and baseline AFP were the significant prognostic factors of OS (hazard ratio [HR] for age; 0.938, confidential interval; 0.886-0.994, P=0.03, HR for AFP; 1.000; 1.000-1.000, P=0.001). Conclusions: Baseline age and AFP levels showed significant prognostic differences among the groups of HCC patients of the various etiologies. NAFLD induced HCC had shown slightly lower OS at five years than viral induced HCC.
Structural Insights into the Interaction of Terpenoids with Streptomyces avermitilis CYP107P2
( Eunseo Jeong ),( Vitchan Kim ),( Changmin Kim ),( Yoo-bin Lee ),( Donghak Kim ) 한국응용약물학회 2024 Biomolecules & Therapeutics(구 응용약물학회지) Vol.32 No.4
Streptomyces avermitilis genome includes 33 genes encoding monooxygenation-catalyzing cytochrome P450 enzymes. We investigated the structure of CYP107P2 and its interactions with terpenoid compounds. The recombinant CYP107P2 protein was expressed in Escherichia coli and the purified enzyme exhibited a typical P450 spectrum upon CO-binding in its reduced state. Type-I substrate-binding spectral titrations were observed with various terpenoid compounds, including α-pinene, β-pinene, α-terpinyl acetate, and (+)-3-carene. The calculated binding affinities (Kd) ranged from 15.9 to 50.8 μM. The X-ray crystal structure of CYP107P2 was determined at 1.99 Å resolution, with a well-conserved overall P450 folding conformation. The terpenoid compound docking models illustrated that the structural interaction between monoterpenes and CYP107P2, with the distance between heme and terpenes ranging from 3.4 to 5.4 Å, indicates potential substrate binding for P450 enzyme. This study suggests that CYP107P2 is a Streptomyces P450 enzyme capable of catalyzing terpenes as substrates, signifying noteworthy advancements in comprehending a novel P450 enzyme’s involvement in terpene reactions.