6.Central N omega-nitro-L-arginine Methyl Ester Does not Influence Lithium-induced c-Fos and Conditioned Taste Aversion.
Jeong Won JAHNG ; Si Ho CHOI ; Dong Goo KIM ; Thomas A HOUPT
Yonsei Medical Journal 2003;44(5):869-874
LiCl at doses sufficient to induce conditioned taste aversion (CTA) causes c-Fos expression in the brain regions implicated in CTA formation. It has been reported that nitric oxide (NO) may play a role in CTA learning and LiCl increases both the synthesis and activity of NO synthase (NOS) in the brain. In this study, we examined the effect of central N omega-nitro-L- arginine methyl ester (L-NAME) on the brain c-Fos expression and CTA learning induced by lithium in rats. In the results, intracerebroventricular L-NAME given prior to lithium did not change either the lithium-induced CTA or c-Fos in the relevant brain regions. This suggests that the brain NO system may not be involved in the neuronal activation during lithium-induced CTA formation.
Animals
;
Avoidance Learning/*drug effects/physiology
;
Brain/*physiology
;
Conditioning (Psychology) /*drug effects/physiology
;
Immunohistochemistry
;
Injections, Intraventricular
;
Lithium/*pharmacology
;
Male
;
NG-Nitroarginine Methyl Ester/*pharmacology
;
Nitric Oxide/physiology
;
Proto-Oncogene Proteins c-fos/*analysis
;
Rats
;
Rats, Sprague-Dawley
;
Support, Non-U.S. Gov't
;
Taste/*drug effects/physiology
7.Bone morphogenetic protein 4 stimulates neuronal differentiation of neuronal stem cells through the ERK pathway.
Byoung San MOON ; Ju Yong YOON ; Mi Yeon KIM ; Sang Hun LEE ; Thomas CHOI ; Kang Yell CHOI
Experimental & Molecular Medicine 2009;41(2):116-125
Bone morphogenic protein 4 (BMP4), a member of the TGF-beta superfamily, induced neural differentiation of neural stem cells (NSCs) grown in a medium containing basic fibroblast growth factor (bFGF). The Ras protein level and the activities of the downstream ERKs were increased by transfection of BMP4 or treatment with recombinant BMP4. The effects of BMP4, including activation of the Ras-ERK pathway and induction of the neuron marker beta-tubulin type III (Tuj1), were blocked by co-treatment of the BMP4 antagonist, noggin. The roles of the Ras-ERK pathway in neuronal differentiation by BMP4 were revealed by measuring the effect of the ERK pathway inhibition by dominant negative Ras or PD98059, the MEK specific inhibitor. BMP4 is a transcriptional target of Wnt/beta-catenin signaling, and both the mRNA and protein levels of BMP4 were increased by treatment of valproic acid (VPA), a chemical inhibitor of glycogen synthase kinase 3beta (GSK3beta) activating the Wnt/beta-catenin pathway. The BMP4- mimicking effects of VPA, activation of the Ras-ERK pathway and induction of Tuj1, also were blocked by noggin. These results indicate the potential therapeutic usage of VPA as a replacement for BMP4.
Animals
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Bone Morphogenetic Protein 4/genetics/*metabolism
;
Cell Differentiation/drug effects
;
Cells, Cultured
;
Cerebral Cortex/cytology/embryology
;
Extracellular Signal-Regulated MAP Kinases/*metabolism
;
Neurons/*cytology
;
Rats
;
Rats, Sprague-Dawley
;
Stem Cells/*cytology
;
Up-Regulation/drug effects
;
Valproic Acid/pharmacology
;
beta Catenin/metabolism
;
ras Proteins/genetics/metabolism
8.Tumor-specific Gene Therapy for Renal Cell Carcinoma Using MN/CA9-directed Replication-competent Adenovirus.
Se Joong KIM ; Miwon AHN ; Ho Yeong LIM ; Cheol Hyun CHUNG ; Thomas A GARDNER ; Chinghai KAO ; Sang Jin LEE ; Min Kyu CHOI ; Young Soo KIM
Korean Journal of Urology 2004;45(5):456-462
PURPOSE: A new therapeutic approach is needed in patients with metastatic renal cell carcinoma (RCC) because of a dismal prognosis. MN/CA9 is a transmembrane glycoprotein that was first identified in the human cervical carcinoma cell line, HeLa. Since MN/CA9 protein is highly expressed in RCC tissues, but not in normal kidney, we constructed a tumor-specific replication-competent adenoviral vector utilizing MN/CA9 promoter (Ad-MN/CA9-E1a) and demonstrated its selective cytotoxicity toward MN/CA9-expressing RCC cells in vitro. MATERIALS AND METHODS: MN/CA9-positive (HeLa, SK-RC-52) and MN/ CA9-negative (SK-RC-29) cells were used. RT-PCR assay for MN/CA9 mRNA was performed in each cells. Ad5 E1a protein production in each cells after infection with Ad-MN/CA9-E1a was determined by western blot analysis. In vitro cytotoxicity assay was performed for assessing the selective cytotoxicity of Ad-MN/CA9-E1a to MN/CA9-expressing cells. RESULTS: RT-PCR assay showed that a distinct 255-bp fragment corresponding to the sequence within MN/CA9 cDNA was detected in HeLa and SK-RC-52 cells, but SK-RC-29 cells did not have MN/CA9 transcripts. Western blot analysis demonstrated that HeLa and SK-RC-52 cells showed much stronger Ad5 E1a protein expressions compared with SK-RC-29. In vitro cytotoxicity assay revealed that the growth of MN/CA9-positive cells was significantly inhibited with 0.1-1MOI of Ad-MN/CA9-E1a, but the growth of MN/CA9-negative cells (SK-RC-29) could only be inhibited by as many as 100MOI. CONCLUSIONS: These results suggest that a novel replication-competent adenoviral vector mediated by MN/CA9 promoter, Ad-MN/CA9-E1a, can selectively replicate in MN/CA9-expressing cancer cells with cytotoxic effects and may be utilized for the treatment of RCC.
Adenoviridae*
;
Blotting, Western
;
Carcinoma, Renal Cell*
;
Cell Line
;
DNA, Complementary
;
Genetic Therapy*
;
Glycoproteins
;
Humans
;
Kidney
;
Prognosis
;
RNA, Messenger
;
Virus Replication
9.Inhibition of expression of P-selectin by antioxidant in cholesterol-fed rats.
Choong Sik LEE ; Jeung Mok CHOI ; Dae Hyun PARK ; Dae Young KANG ; Thomas C REGISTER ; Michael R ADAMS
Journal of Korean Medical Science 1999;14(1):8-14
Butylated hydroxytoluene (BHT) can inhibit experimental atherosclerosis in animals. Although the agent is an antioxidant, the exact mechanism of the reaction in atherosclerosis is still unknown. To investigate the effects of BHT on expression of P-selectin (PADGEM, GMP-140), intercellular adhesion molecule-1 (ICAM-1) and class II MHC (Ia) antigen, we proposed an experiment on rats. Male rats (n=18 per group) were fed either a normal cholesterol control diet, a normal cholesterol diet containing 0.5% BHT (BD), a high cholesterol diet containing 1.5% cholesterol and 0.1% sodium cholate (CD), or the CD diet containing 0.5% BHT (BCD). Rats were sacrificed after 3 days, and after 1, 2, 4, 10, and 17 weeks of dietary treatment. Although there was no gross or light microscopic atherosclerotic lesions, scanning electron microscopy revealed monocytic adhesion to aortic endothelium and mild endothelial injuries in CD and BCD groups. Immunohistochemically, the addition of BHT to a high cholesterol diet inhibited P-selectin expression but not in ICAM-1 and Ia antigen. These findings suggest that in rats, high cholesterol diets induce expression of ICAM-1, P-selectin and Ia antigen. In addition, the antiatherogenic effect of BHT may play a role in the inhibition of P-selectin.
Animal
;
Antioxidants/pharmacology
;
Antioxidants/metabolism*
;
Aorta, Abdominal/ultrastructure
;
Aorta, Abdominal/pathology
;
Aorta, Thoracic/ultrastructure
;
Aorta, Thoracic/pathology
;
Butylated Hydroxytoluene/pharmacology
;
Butylated Hydroxytoluene/metabolism*
;
Cholesterol/metabolism
;
Cholesterol, Dietary/metabolism*
;
Male
;
Microscopy, Electron, Scanning
;
P-Selectin/biosynthesis*
;
Rats
;
Rats, Sprague-Dawley
10.Deep Learning-Accelerated Non-Contrast Abbreviated Liver MRI for Detecting Malignant Focal Hepatic Lesions: Dual-Center Validation
So Hyun PARK ; Moon Hyung CHOI ; Bohyun KIM ; Hyun-Soo LEE ; Sungjin YOON ; Young Joon LEE ; Dominik NICKEL ; Thomas BENKERT
Korean Journal of Radiology 2025;26(4):333-345
Objective:
To compare a deep learning (DL)-accelerated non-enhanced abbreviated MRI (AMRI DL) protocol with standard AMRI (AMRI STD) of the liver in terms of image quality and malignant focal lesion detection.
Materials and Methods:
This retrospective study included 155 consecutive patients (110 male; mean age 62.4 ± 11 years) from two sites who underwent standard liver MRI and additional AMRIDL sequences, specifically DL-accelerated single-shot fast-spin echo (SSFSE DL) and DL-accelerated diffusion-weighted imaging (DWIDL). Additional MRI phantom experiments assessed signal-to-noise ratio (SNR), contrast-to-noise ratio (CNR), and apparent diffusion coefficient (ADC) values. Three reviewers evaluated AMRIDL and AMRI STD protocols for image quality using a five-point Likert scale and identified malignant hepatic lesions. Image quality scores and per-lesion sensitivities were compared between AMRIDL and AMRI STD using the Wilcoxon signed-rank test and logistic regression with generalized estimating equations, respectively.
Results:
Phantom experiments demonstrated comparable SNR and higher CNR for SSFSE DL compared to SSFSE STD, with similar ADC values for DWIDL and DWI STD. Among the 155 patients, 130 (83.9%) had chronic liver disease or a history of intra- or extrahepatic malignancy. Of 104 malignant focal lesions in 64 patients, 58 (55.8%) were hepatocellular carcinomas (HCCs), 38 (36.5%) were metastases, four (3.8%) were cholangiocarcinomas, and four (3.8%) were lymphomas. The pooled per-lesion sensitivity across three readers was 97.6% for AMRIDL, comparable to 97.6% for AMRI STD. Compared with AMRI STD, AMRIDL demonstrated superior image quality regarding structural sharpness, artifacts, and noise (all P < 0.001) and reduced the average scan time by approximately 50% (2 min 29 sec vs. 4 min 11 sec). In patients with chronic liver disease, AMRIDL achieved a 96.6% per-lesion sensitivity for HCC detection, similar to 96.5% for AMRI STD (P > 0.05).
Conclusion
The AMRIDL protocol offers comparable sensitivity for detecting malignant focal lesions, including HCC while significantly enhancing image quality and reducing scan time by approximately 50% compared to AMRI STD.