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Hamilton AM, Lambert JT, Parajuli LK, Vivas O, Park DK, Stein IS, Jahncke JN, Greenberg ME, Margolis SS, Zito K. A dual role for the RhoGEF Ephexin5 in regulation of dendritic spine outgrowth. Mol Cell Neurosci 2017; 80:66-74. [PMID: 28185854 DOI: 10.1016/j.mcn.2017.02.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 02/01/2017] [Accepted: 02/04/2017] [Indexed: 12/28/2022] Open
Abstract
The outgrowth of new dendritic spines is closely linked to the formation of new synapses, and is thought to be a vital component of the experience-dependent circuit plasticity that supports learning. Here, we examined the role of the RhoGEF Ephexin5 in driving activity-dependent spine outgrowth. We found that reducing Ephexin5 levels increased spine outgrowth, and increasing Ephexin5 levels decreased spine outgrowth in a GEF-dependent manner, suggesting that Ephexin5 acts as an inhibitor of spine outgrowth. Notably, we found that increased neural activity led to a proteasome-dependent reduction in the levels of Ephexin5 in neuronal dendrites, which could facilitate the enhanced spine outgrowth observed following increased neural activity. Surprisingly, we also found that Ephexin5-GFP levels were elevated on the dendrite at sites of future new spines, prior to new spine outgrowth. Moreover, lowering neuronal Ephexin5 levels inhibited new spine outgrowth in response to both global increases in neural activity and local glutamatergic stimulation of the dendrite, suggesting that Ephexin5 is necessary for activity-dependent spine outgrowth. Our data support a model in which Ephexin5 serves a dual role in spinogenesis, acting both as a brake on overall spine outgrowth and as a necessary component in the site-specific formation of new spines.
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Affiliation(s)
- A M Hamilton
- Center for Neuroscience, University of California Davis, Davis, CA 95618, USA
| | - J T Lambert
- Center for Neuroscience, University of California Davis, Davis, CA 95618, USA
| | - L K Parajuli
- Center for Neuroscience, University of California Davis, Davis, CA 95618, USA
| | - O Vivas
- Center for Neuroscience, University of California Davis, Davis, CA 95618, USA
| | - D K Park
- Center for Neuroscience, University of California Davis, Davis, CA 95618, USA
| | - I S Stein
- Center for Neuroscience, University of California Davis, Davis, CA 95618, USA
| | - J N Jahncke
- Center for Neuroscience, University of California Davis, Davis, CA 95618, USA
| | - M E Greenberg
- Department of Neurobiology, Harvard Medical School, Boston, MA 02115, USA
| | - S S Margolis
- Department of Biological Chemistry, Johns Hopkins School of Medicine, Baltimore, MD 21205, USA
| | - K Zito
- Center for Neuroscience, University of California Davis, Davis, CA 95618, USA.
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Kim EK, Cho JH, Jeong AR, Kim EJ, Park DK, Kwon KA, Chung JW, Kim KO, Kim JH, Kim JH, Kim YJ. Anti-inflammatory effects of simvastatin in nonsteroidal anti-inflammatory drugs-induced small bowel injury. J Physiol Pharmacol 2017; 68:69-77. [PMID: 28456771] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Received: 08/17/2016] [Accepted: 02/24/2017] [Indexed: 06/07/2023]
Abstract
Small bowel injury can occur as the result of a multifaceted process that includes increased acid secretion, generation of reactive oxygen species, and cyclooxygenase inhibition. However, no effective medication for small bowel ulceration is available. Simvastatin is an important lipid-lowering agent with anti-inflammatory activity. We aimed to validate the effects of simvastatin in vitro and in vivo. In presence or absence of simvastatin, IEC-6 small bowel cell line with 50 ng/ml of tumor nectosis factor α (TNF-α) was investigated by western blotting, qRT-PCR, and DCF-DA assay. In addition, an in vivo study of nonsteroidal anti-inflammatory drugs (NSAID)-induced small bowel inflammation was performed using 7-week-old specific-pathogen-free (SPF) male C57BL/6 mice. Simvastatin treatment reduced the mRNA levels of interleukin-6 and interleukin-8 by approximately 50% in TNF-α-stimulated IEC-6 cells. Treatment with a combination of 50 ng/ml TNF-α and μM simvastatin decreased activation of Akt, IκBα, and nuclear factor-κB p65 level in IEC-6 cells. By DCF-DA staining, intracellular reactive oxygen species (ROS) production was increased in TNF-α-stimulated cells, and treatment with simvastatin decreased the level of ROS. In addition, in vivo mouse model of NSAID-induced small bowel inflammation, the administration of simvastatin reduced the number of small bowel hemorrhagic lesions and the level of ROS production as determined by gross examination and 8-hydroxydeoxyguanosine immunohistochemistry of small bowel tissue, respectively. Simvastatin reduced NSAID-induced injuries by both suppression of ROS generation and modulation of inflammatory cytokines in vitro and in vivo. Therefore, simvastatin, an HMG-CoA reductase inhibitor, has potential as a prophylactic and therapeutic agent for NSAID-induced small bowel injury.
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Affiliation(s)
- E K Kim
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea.
- Gachon Medical Research Institute, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - J H Cho
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - A R Jeong
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - E J Kim
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - D K Park
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - K A Kwon
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - J W Chung
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - K O Kim
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - J H Kim
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - J H Kim
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
| | - Y J Kim
- Division of Gastroenterology, Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, Republic of Korea
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Affiliation(s)
- C S Jang
- Department of Gastroenterology and Hepatology, Gachon University Gil Medical Center, Incheon, South Korea
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Kwon SY, Kim SS, Kwon OS, Kwon KA, Chung MG, Park DK, Kim YS, Koo YS, Kim YK, Choi DJ, Kim JH. Prognostic significance of glycaemic control in patients with HBV and HCV-related cirrhosis and diabetes mellitus. Diabet Med 2005; 22:1530-5. [PMID: 16241918 DOI: 10.1111/j.1464-5491.2005.01687.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
AIMS Diabetes mellitus (DM) is frequently observed in patients with cirrhosis, particularly that due to hepatitis C virus (HCV) infection. However, no studies have focused on the clinical significance of glycaemic control in cirrhotic patients because of their short life expectancy and poor hepatic function. The aim of this study was to evaluate the prognostic impact of glycaemic control in patients with hepatitis B virus (HBV) and HCV-related cirrhosis and DM. METHODS A total of 434 patients with HCV-related (HCV group, n = 88) or HBV-related (HBV group, n = 346) cirrhosis were studied retrospectively. We determined the prevalence of DM and treatment methods for hyperglycaemia and status of glycaemic control, and the patients' outcome. RESULTS The prevalence of DM was 43.2% (38/88) in the HCV group and 19.7% (68/346) in the HBV group. Patients in the HCV group were older with a female preponderance. DM was detected before the diagnosis of cirrhosis or simultaneously in 92% and 79% in the HCV and HBV groups, respectively. Most patients were treated with insulin or oral hypoglycaemic agents. However, blood glucose levels were maintained within the normal range in 34.2% of the HCV group and in 23.5% of the HBV group. Forty-six patients died during the observation period in both groups. Hepatic failure was the most common cause of death, and sepsis and variceal bleeding were more frequent in the HCV group than in the HBV group. Multivariate analysis showed that Child-Pugh class was the most important factor for survival in both groups. In the HCV group, the status of glycaemic control was a significant independent factor of survival (P = 0.018). In the HBV group, age and the development of spontaneous bacterial peritonitis were significant. CONCLUSION DM is more frequent in patients with HCV-related cirrhosis than in patients with HBV. Strict control of blood glucose levels could improve survival in HCV patients. A precise assessment of the risks and benefits of glycaemic control is required to reduce the mortality and morbidity of patients with cirrhosis and DM.
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Affiliation(s)
- S Y Kwon
- Gil MerDepartment of Internal Medicine, Division of Gastroenterology and Hepatology, Gachon Medical School, Gil Medical Centre, 1198 Guwal-dong, Namdong-gu, Inchon 405-760, Korea.
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Park DK, Ryan CW, Dolan ME, Vogelzang NJ, Stadler WM. A phase II trial of oral temozolomide in patients with metastatic renal cell cancer. Cancer Chemother Pharmacol 2002; 50:160-2. [PMID: 12172983 DOI: 10.1007/s00280-002-0473-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2002] [Accepted: 04/23/2002] [Indexed: 11/25/2022]
Abstract
PURPOSE To determine the activity of temozolomide, an oral imidazotetrazine alkylating agent that has exhibited broad antitumor activity in preclinical studies, in renal cell cancer (RCC) patients. METHODS. Metastatic RCC patients were treated with temozolomide, 200 mg/m(2) per day orally, and traditional radiologic response endpoints were assessed. O(6)-Alkylguanine-DNA alkyltransferase (AGT) activity was measured in four pretreatment biopsies. RESULTS Among 12 patients, there were no responses. High AGT activity was observed in all four biopsies analyzed. CONCLUSIONS Temozolomide is not active against RCC and this clinical observation may be due to high levels of AGT in this tumor.
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Affiliation(s)
- D K Park
- Department of Medicine, University of Chicago, Chicago, IL 60637, USA
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Kwon OS, Lee HS, Koh DW, Cho YJ, Park YH, Park DK, Oh YL, Seo JH, Chun HJ, Um SH, Lee SW, Choi JH, Kim CD, Ryu HS, Hyun JH, Kim AR, Kim YS. A case of primary adenosquamous carcinoma of the liver presented with liver abscess. Korean J Intern Med 2001; 16:270-3. [PMID: 11855159 PMCID: PMC4578056 DOI: 10.3904/kjim.2001.16.4.270] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Primary adenosquamous carcinoma of the liver is a very rare type of cholangiocarcinoma and is defined as a cancer containing both squamous and adenomatous components in the same lesion. Recently, we experienced a primary adenosquamous carcinoma of the liver presented as liver abscess. A 63-year-old man was presented with a 4-day history of fever and chill. The radiologic study showed a 4 cm-sized, central hypoattenuated mass with peripheral rim enhancement in the left lobe of the liver. Ultrasonography-guided aspiration and biopsy suggested an adenocarcinoma with abscess in the liver. At laparotomy, the tumor occupied the left lobe of the liver and invaded the right diaphragm. An extended left lobectomy and a partial excision of the involved diaphragm were done. Grossly, the tumor was 6 x 5 x 5 cm in size and had an eccentric necrosis. Microscopically, the tumor was composed of adenocarcinoma and squamous cell carcinoma with a transitional area.
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Affiliation(s)
- O S Kwon
- Department of Internal Medicine, Korea University, Ansan Hospital, 516 Kojan-Dong, Ansan City, Kyungki-Do, 425-020, Korea
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Chung MG, Kang DH, Park DK, Park JJ, Park HC, Kim JH. Successful treatment of Boerhaave's syndrome with endoscopic insertion of a self-expandable metallic stent: report of three cases and a review of the literature. Endoscopy 2001; 33:894-7. [PMID: 11571689 DOI: 10.1055/s-2001-17325] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/10/2022]
Abstract
Boerhaave's syndrome is a rare but life-threatening condition which presents a diagnostic as well as therapeutic challenge. Early diagnosis and prompt surgical repair are critical for survival; however late recognition of esophageal rupture is not unusual. A variety of nonsurgical approaches have been proposed, particularly in the case of delayed diagnosis. In recent years, the insertion of a metallic stent has been described as a promising modality in the treatment of spontaneous esophageal rupture. We report three cases of Boerhaave's syndrome treated with self-expandable metallic stents and review previously published cases.
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Affiliation(s)
- M G Chung
- Department of Internal Medicine, Gachon Medical School, Inchon, Korea
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Yang YS, Park DK, Kim HC, Choi MH, Chai JY. Automatic identification of human helminth eggs on microscopic fecal specimens using digital image processing and an artificial neural network. IEEE Trans Biomed Eng 2001; 48:718-30. [PMID: 11396601 DOI: 10.1109/10.923789] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
In order to automate routine fecal examination for parasitic diseases, we propose in this study a computer processing algorithm using digital image processing techniques and an artificial neural network (ANN) classifier. The morphometric characteristics of eggs of human parasites in fecal specimens were extracted from microscopic images through digital image processing. An ANN then identified the parasite species based on those characteristics. We selected four morphometric features based on three morphological characteristics representing shape, shell smoothness, and size. A total of 82 microscopic images containing seven common human helminth eggs were used. The first stage (ANN-1) of the proposed ANN classification system isolated eggs from confusing artifacts. The second stage (ANN-2) classified eggs by species. The performance of ANN was evaluated by the tenfold cross-validation method to obviate the dependency on the selection of training samples. Cross-validation results showed 86.1% average correct classification ratio for ANN-1 and 90.3% for ANN-2 with small variances of 46.0 and 39.0, respectively. The algorithm developed will be an essential part of a completely automated fecal examination system.
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Affiliation(s)
- Y S Yang
- Interdisciplinary Program Biomedical Engineering Major, Seoul National University, Korea
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Abstract
Dietary restriction (DR) increases life span and decreases age-related diseases in experimental animals. It has received a great deal of attention in connection with the relationship between aging, nutrition, and oxidative stress because oxidative injury in several organ systems is a prominent feature in aging. We investigated the possibility that DR can protect vulnerable liver lipids against age-related increases of peroxidation. Male Fischer 344 rats fed ad libitum (AL) or dietarily restricted (maintained on 60% of AL food intake) were killed by decapitation at 4 (young) or 12 mon (adult) of age. Phosphatidylcholine hydroperoxide (PCOOH) concentration of liver was determined using a chemiluminescent high-performance liquid chromatographic method. Liver PCOOH increased with age in adult rats, but less of an increase of PCOOH was seen in DR rats, which is consistent with results on production of thiobarbituric acid-reactive substances and oxygen-derived free radicals. No significant differences were found in liver superoxide dismutase and catalase activity between AL and DR groups of young and adult rats. Liver triglyceride and cholesterol contents were lower in DR than AL rats at 12 mon. Fatty acid compositions of phosphatidylcholine and phosphatidylethanolamine indicated that the ratio of (20:3n-6 + 20:4n-6)/18:2n-6, an index of linoleic acid (18:2n-6) desaturation, was lower in DR than in AL rats. We concluded that DR suppresses age-related oxidative damage in liver by modulating the amount of lipid as well as fatty acid composition.
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Affiliation(s)
- T I Jeon
- Department of Applied Biology and Chemistry, Konkuk University, Seoul, Korea
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Kim EA, Kang DH, Cho HS, Park DK, Kim YK, Park HC, Kim JH. Acid secretion from a heterotopic gastric mucosa in the upper esophagus demonstrated by dual probe 24-hour ambulatory pH monitoring. Korean J Intern Med 2001; 16:14-7. [PMID: 11417299 PMCID: PMC4531699 DOI: 10.3904/kjim.2001.16.1.14] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Heterotopic gastric mucosa in the upper esophagus is frequently found during endoscopic examination. Although most patients with heterotopic gastric mucosa of the upper esophagus, referred as inlet patch, are asymptomatic, symptomatic patients with complications resulting from this ectopic mucosa have also been reported. Acid secretion by the inlet patch has been suggested in some reports. We report a case of heterotopic gastric mucosa in the upper esophagus, with secretion of acid, demonstrated by continuous ambulatory pH monitoring, and the improvement of pharyngeal symptoms after the use of a proton pump inhibitor.
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Affiliation(s)
- E A Kim
- Department of Internal Medicine, Gachon Medical School, Inchon, Korea
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Abstract
The role of ascorbic acid on dopamine (DA) oxidation-mediated cytotoxicity was studied using the PC12 cell line. DA cytotoxicity was slightly attenuated by ascorbic acid, whereas the cytotoxicity of 6-hydroxydopamine (6-OHDA), a DA oxidation product, was markedly potentiated. To elucidate the relationship between the ascorbic acid effect and the degree of DA oxidation, ascorbic acid was added in a time-dependent fashion after DA treatment. We found greater cell death the later ascorbic acid was applied. Treatment of cells with glutathione alleviated DA- and 6-OHDA-induced cell death, while L-buthionine sulfoximine potentiated DA and 6-OHDA cytotoxicity. Ascorbic acid combined with glutathione eliminated the toxicity of DA and 6-OHDA. These results suggest that the interaction between DA and ascorbic acid is dependent upon the degree of DA oxidation and glutathione availability.
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Affiliation(s)
- H Y Choi
- Department of Physiology, Queen's University, Kingston, K7L 3N6, Ontario, Canada
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Cho JH, Roe IH, Lim CY, Park DK, Kim WH, Kim YI. Topographic expression of p21WAF1/SDI1/CIP1, bcl2, and p53 is altered at the early stage of colorectal carcinogenesis. J Korean Med Sci 2000; 15:667-74. [PMID: 11194193 PMCID: PMC3054698 DOI: 10.3346/jkms.2000.15.6.667] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We analyzed the expression of p21, bcl2, and p53 in normal and different pathologic mucosa of the human colorectum using immunohistochemistry and cold polymerase chain reaction-single strand conformation polymorphism. The topography of normal mucosa showed; bcl2 and p53 expression restricted to basal epithelial cells and p21 expressed only in superficial epithelial cells. This topographic expression was altered in hyperplastic polyps and adenomas. Hyperplastic polyps revealed absence of or weak bcl2 expression and strong p21 expression without topography. In adenomas, whereas bcl2 expression increased and extended to parabasal and superficial dysplastic epithelium, the increase of p21 expression was limited to surface dysplastic epithelium. p53 was weakly expressed throughout the full thickness of dysplastic epithelium. Bcl2 expression in adenomas was stronger than in carcinomas; p53 expression was converse and p21 expression was variable. In carcinomas, this topographic expression was largely abrogated but p53 mutation (36%) was more frequent than in adenomas (2%). In carcinomas, p21 and p53 expression correlated inversely, but there was no relationship with bcl2. These results suggest that there is precisely ordered topographic pattern of p21, bcl2, and wild p53 expression in normal colorectal cells, but this becomes disordered during the early stage of colorectal carcinogenesis.
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Affiliation(s)
- J H Cho
- Molecular Pathology, University of Texas, MD Anderson Cancer Center, Houston 77030, USA.
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Abstract
The development of cholinergic cells in the rat retina has been examined with immunocytochemistry by using antisera against choline acetyltransferase (ChAT). ChAT-immunoreactive (IR) cells were first detected at embryonic day 17 (E17) in the transitional zone between the neuroblastic layer (NBL) and ganglion cell layer (GCL). At E20, ChAT-IR cells are located exclusively in the GCL. At postnatal day 0 (P0), ChAT immunoreactivity appeared for the first time in cells at the distal margin of the NBL. Two prominent bands of labeled processes were first visible at P3, and by P15, these two bands resembled those of the adult retina. In addition, ChAT immunoreactivity appeared transiently in horizontal cells from P5 to P10. The number of ChAT-IR cells increased steadily up to P15. This resulted in a 93.8-fold increase between E17 and P15 (680-63,800 cells). However, after P15, the number declined by 19% from 63,800 cells at P15 to 51,800 in the adult. At all ages, the spatial density of each ChAT-IR cell population in the central retina was higher than in the periphery. In both central and peripheral regions, the peak density of ChAT-IR cells in the GCL was attained at E20. However, in the INL, the peak densities occurred at P3 in the central region and at P5 in the peripheral region. Up to P15, the soma diameter of ChAT-IR cells in the INL and GCL in each region increased continuously, reaching peak values at P15. Our results demonstrate that ChAT immunoreactivity is expressed in early developmental stages in the rat retina, as in other mammals, and that acetylcholine released from ChAT-IR cells may have neurotrophic functions in retinal maturation.
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Affiliation(s)
- I B Kim
- Department of Anatomy, College of Medicine, The Catholic University of Korea, Seoul 137-701, Korea
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Ju WK, Kim KY, Park SJ, Park DK, Park CB, Oh SJ, Chung JW, Chun MH. Nitric oxide is involved in sustained and delayed cell death of rat retina following transient ischemia. Brain Res 2000; 881:231-6. [PMID: 11036166 DOI: 10.1016/s0006-8993(00)02816-x] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We have investigated the role of nitric oxide (NO) in the rat retina following ischemic injury induced by transient increase of intraocular pressure. The thickness of both the inner plexiform layer and inner nuclear layer decreased during early postischemic stages (up to 1 week). In late postischemic stages (2-4 weeks), the thickness of the outer nuclear layer (ONL) decreased markedly. Thus, mechanisms other than excitotoxic ones may contribute to postischemic retinal cell death. Treatment of rats with N(G)-nitro-L-arginine methyl ester, a nitric oxide synthase (NOS) inhibitor, significantly reduced ischemic damage. Our findings suggest that NO is involved in the mechanism of ischemic injury, and plays a key role in the delayed and sustained cell death in the ONL following transient retinal ischemia.
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Affiliation(s)
- W K Ju
- Department of Anatomy, College of Medicine, The Catholic University of Korea, 505 Banpo-dong, Socho-gu, 137-701, Seoul, South Korea
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Abstract
Chemiluminescence (CL) was observed during the oxidation of luminol (2 mg/L). mediated by 0.06% hydrogen peroxide (H(2)O(2)) and cytochrome c (10 mg/L). CL intensity was decreased by the presence of radical scavengers and the reduction was linearly proportional to the concentration and ability of scavengers; butylated hydroxytoluene (BHT), caffeic acid and gallic acid. The order of effectiveness as radical scavengers was gallic acid > caffeic acid > BHT, which shows that the number of hydroxyl groups (OH) in the B-ring of flavonoids plays a key role in a good radical scavenging activity. Of eight catechins obtained from green tea extracts, (-)-catechin was the least effective and (-)-epigallocatechin gallate (EGCg) showed the strongest activity. This result indicates that the stereoscopic structure between the C-3 group and the B ring of flavonoids as well as substituents at the C-3 position make a contribution to radical scavenging activity. Of the tested Chinese herbal ingredients, five species of ingredients represented more than 90% of the radical scavenging activity.
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Affiliation(s)
- H Y Choi
- Department of Biochemistry, Konkuk University, Chungju, Chungbuk, Korea, 380-701
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Abstract
The antioxidative effect of ganhuangenin (GHG), isolated from Scutellaria baicalensis Georgi, was examined by measuring its ability to suppress the formation of phospatidylcholine hydroperoxide (PCOOH). The results show that a pretreatment with GHG effectively suppressed PCOOH formation, which was initiated by the peroxyl-generating oxidant, AAPH (2,2'-azobis-2-aminopropane hydrochloride). The protective action of GHG against the formation of the PCOOH was observed in liver, lung, and kidney. When compared with other known antioxidants, we found the antioxidative potency of GHG to be greater than that of alpha-tocopherol. Our data strongly indicate that GHG is a powerful antioxidant against lipid peroxidation and is, therefore, responsible for this prophylactic effect.
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Affiliation(s)
- B O Lim
- Department of Physiology, The University of Texas Health Science Center, San Antonio, Texas, 78284-7756, USA
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Park DK. Australian uprighting spring for partially impacted second molars. J Clin Orthod 1999; 33:404-5. [PMID: 10535023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/14/2023]
Affiliation(s)
- D K Park
- School of Medicine, Inje University, Korea
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Affiliation(s)
- H Y Choi
- Department of Biochemistry, Kon-Kuk University, Chungju, Korea
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Kim IB, Park DK, Oh SJ, Chun MH. Horizontal cells of the rat retina show choline acetyltransferase- and vesicular acetylcholine transporter-like immunoreactivities during early postnatal developmental stages. Neurosci Lett 1998; 253:83-6. [PMID: 9774155 DOI: 10.1016/s0304-3940(98)00605-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
We examined cholinergic neurons in the developing rat retina; an antiserum against choline acetyltransferase (ChAT) and an antiserum against vesicular acetylcholine transporter (VAChT) were used. From postnatal day 4 (P4) to P10, ChAT- and VAChT-like immunoreactivities were seen in cells which were located in the outer part of the inner nuclear layer. These cells had relatively large cell bodies and extended several transversely oriented processes. Double fluorescence immunohistochemistry using an antiserum against calbindin D-28K, a specific marker for the horizontal cells, revealed that all of ChAT- or VAChT-labeled cells showed calbindin D-28K-like immunoreactivity. These cells were no longer immunostained after P11. Thus, acetylcholine was considered to be transiently synthesized in the horizontal cells during early postnatal developmental stages in the rat retina.
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Affiliation(s)
- I B Kim
- Department of Anatomy, Catholic University Medical College, Seoul, South Korea
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Nakagawa K, Kang SD, Park DK, Handelman GJ, Miyazawa T. Inhibition of beta-carotene and astaxanthin of NADPH-dependent microsomal phospholipid peroxidation. J Nutr Sci Vitaminol (Tokyo) 1997; 43:345-55. [PMID: 9268922 DOI: 10.3177/jnsv.43.345] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
To evaluate the antioxidant effects of beta-carotene and astaxanthin, rat liver microsomes were exposed to a mixture of chelated iron (Fe3+/ADP) and NADPH. The carotenoids (190 pmol/mg protein) were incorporated into some of these microsomal membranes, and phospholipid hydroperoxides (PLOOH), thiobarbituric acid reactive substances (TBARS) and endogenous alpha-tocopherol content were measured over time after the initiation of oxidant stress. In control microsomes, oxidant stress led to accumulation of 1,865 (+/- 371) pmol PLOOH/mg protein during the initial 10-min peroxidation reaction, followed by a more gradual decrease during the subsequent 20-min of reaction. PLOOH accumulation during the initial 10-min reaction period was reduced to 588 (+/- 169) pmol/mg protein with beta-carotene present and 800 (+/- 288) pmol/mg protein with astaxanthin present. During the following 20-min of incubation, PLOOH levels declined in the carotenoid-supplemented microsomes but continued to increase at a slower rate in control preparations. TBARS did not show such large accumulation as observed in PLOOH during the initial 10-min incubation in any microsomal sample. The presence of carotenoids in the microsomal membrane partially inhibited the loss of alpha-tocopherol, especially during the later phase of oxidant stress. When lipid peroxidation is generated by membrane-bound cyt-P450, the specific measurement of PLOOH clearly demonstrates that the presence of carotenoids provides antioxidant protection.
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Affiliation(s)
- K Nakagawa
- Department of Applied Biological Chemistry, Tohoku University, Sendai, Japan
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Abstract
We report two cases of lipoma of the parotid gland which present as a non-tender, freely movable and intraparotid mass. Lipomas are common soft tissue neoplasms but found very rarely in the parotid gland, and so are often not considered in the initial differential diagnosis of parotid gland tumor. We believe that these tumors are cured by simple excision, and thus superficial parotidectomy is enough for treatment.
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Affiliation(s)
- J W Ryu
- Department of General Surgery, College of Medicine, Dankook University, Chung-cheong Nam Do, Korea
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Widmalm SE, Williams WJ, Christiansen RL, Gunn SM, Park DK. Classification of temporomandibular joint sounds based upon their reduced interference distribution. J Oral Rehabil 1996; 23:35-43. [PMID: 8850159 DOI: 10.1111/j.1365-2842.1996.tb00809.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Temporomandibular joint (TMJ) sounds were recorded in 98 orthodontic retention patients, mean age 19 +/- 8.6 (s.d.) years, by interview, auscultation and electronic recording. Sounds were found by auscultation in 41% and by interview in 32% of the subjects, more often in females than in males (P < 0.05). A new method for time-frequency analysis, the reduced interference distribution (RID), was used to classify the electronic sound recordings into five subclasses, RID types 1-5, based upon location and number of their energy peaks. RID types 1-3 had a few energy peaks close in time. RID types 4-5, typical of subjects with crepitation, had multiple energy peaks occurring close in time for a period of 20-300 ms. RID type 1, found in 45% of the subjects, typical of patients with clicking, had its dominant energy peak located in a frequency range < 600 Hz and was significantly more common in the female than in the male subjects (P < 0.01). RID type 2, found in 68% of the subjects, with the dominant peak in the range 600-1200 Hz, and RID type 3, found in 38% of the subjects, with the peak in the frequency range > 1200 Hz, were found to have a similar gender distribution. RID type 4, found in 49% of the subjects, had the energy peaks distributed in the frequency range < 600 Hz. RID type 5, found in 43% of the subjects, more often in females than in males (P < 0.05), had the peaks distributed over the whole frequency range from about 30 Hz up to about 3000 Hz. In conclusion, a more detailed classification could be made of the TMJ sounds by displaying the RIDs than by auscultation. This suggests that RID classification methods may provide a means for differentiating sounds indicating different types of pathology.
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Affiliation(s)
- S E Widmalm
- Department of Biologic & Materials Sciences, University of Michigan, Ann Arbor, USA
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26
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Park DK. Propagators on the two-dimensional light cone. Phys Rev D Part Fields 1995; 52:6192-6194. [PMID: 10019151 DOI: 10.1103/physrevd.52.6192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Lee YS, Park DK, Kim YB, Seo JW, Lee KB, Min BG. Endothelial cell seeding onto the extracellular matrix of fibroblasts for the development of a small diameter polyurethane vessel. ASAIO J 1993; 39:M740-5. [PMID: 8268636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
A variety of experiments of endothelial cell seeding on artificial vessels have been performed. To improve endothelialization, one or two extracellular matrix components have been used as an underlying matrix. Although these methods have succeeded in in vitro experiments, they have not performed well in vivo. In this study, the authors used the whole extracellular matrix (ECM) excreted from fibroblasts as an underlying matrix. Fetal human fibroblasts were cultured on a polyurethane (PU) sheet. After confluence was attained, the cytoskeleton and the nuclei of the fibroblasts were destroyed using Triton-X, mitomycin, and irradiation. Omental microvascular endothelial cells from adult humans were seeded on various supports. After 12 days in culture, the cells were counted. The authors found that the ECM treated by irradiation had the highest cell number. In addition, the cells on this support exhibited the best morphologic appearance. Finally, the authors performed preliminary animal experiments. The PU vessels (inner diameter: 1.5 mm) treated with ECM were implanted in the arteries of rats. After the vessels had been implanted for 5 weeks, the authors found that the surface of the PU vessels were completely covered with endothelial cells. On the basis of these results, the authors conclude that the whole ECM makes a better underlying substrate for the endothelialization of small diameter artificial vessels.
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Affiliation(s)
- Y S Lee
- Department of Biomedical Engineering, Seoul National University Hospital, Korea
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Jang JS, Park DK, Chun M, Byun SM. Identification of autoproteolytic cleavage site in the Asp-49 mutant subtilisin J by site-directed mutagenesis. Biochim Biophys Acta 1993; 1162:233-5. [PMID: 8448190 DOI: 10.1016/0167-4838(93)90154-j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Ser-49 located at the exposed surface loop of subtilisin J was replaced with Asp and Arg. Proteinase activity of the Asp-49 mutant was similar to that of wild-type, but the Arg mutant was inactivated. At 37 degrees C, mature subtilisin J protein of the Asp-49 mutant rapidly degraded, and specific breakdown products were accumulated. These proteins were analyzed by SDS-PAGE, and the N-terminal sequences were determined for the mature and deleted protein. We identified the autoproteolytic cleavage site in the mature Asp-49 mutant protein from sequencing data.
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Affiliation(s)
- J S Jang
- Department of Agricultural Chemistry, Korea University, Seoul
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Park DK. Gauge-invariant formulation of chiral bosonization. Phys Rev D Part Fields 1990; 42:2841-2845. [PMID: 10013155 DOI: 10.1103/physrevd.42.2841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Kim WT, Park DK, Cho BH. BRS analysis of the non-Abelian chiral Schwinger model. Phys Rev D Part Fields 1988; 38:2586-2590. [PMID: 9959422 DOI: 10.1103/physrevd.38.2586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Park DK, Yi SH, Cho BH, Myung YS. Becchi-Rouet-Stora analysis of the bosonized chiral Schwinger model. Phys Rev D Part Fields 1987; 36:2481-2483. [PMID: 9958457 DOI: 10.1103/physrevd.36.2481] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Ro KK, Cho NH, Park DK. [Population change and economic development in Korea (author's transl)]. Ingu Pogon Nonjip 1983; 3:3-34. [PMID: 12339137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/26/2023]
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36
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Rhim JS, Park DK, Arnstein P, Nelson-Rees WA. Neoplastic transformation of canine embryo cells in vitro by N-methyl-N'-nitro-N-nitrosoguanidine. Int J Cancer 1978; 22:441-6. [PMID: 700899 DOI: 10.1002/ijc.2910220412] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
A cell line derived from a normal beagle embryo was treated in vitro with various levels of N-methyl-N'-nitro-N-nitrosoguanidine or dimethyl sulfoxide (control). Cells treated only with the carcinogen underwent morphologic alteration in vitro, and one of these altered cell lines produced tumors subcutaneously when injected into NIH nude mice. The tumorigenic transformed line formed larger cell aggregates and grew in this aggregate form when suspended in liquid growth medium above an agar base.
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Rhim JS, Park DK, Vernon ML. "Nonproductive" mouse sarcoma virus transformed gorilla cells which contain noninfectious type C virus particles. Exp Biol Med (Maywood) 1978; 158:304-9. [PMID: 210462 DOI: 10.3181/00379727-158-40193] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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Putman DL, Park DK, Rhim JS, Steuer AF, Ting RC. Correlation of cellular aggregation of transformed cells with their growth in soft agar and tumorigenic potential. Exp Biol Med (Maywood) 1977; 155:487-94. [PMID: 197535 DOI: 10.3181/00379727-155-39836] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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39
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Rhim JS, Park DK, Arnstein P, Huebner RJ, Weisburger EK, Nelson-Rees WA. Transformation of human cells in culture by N-methyl-N'-nitro-N-nitrosoguanidine. Nature 1975; 256:751-3. [PMID: 1057046 DOI: 10.1038/256751a0] [Citation(s) in RCA: 81] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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40
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Rhim JS, Park DK, Weisburger EK, Weisburger JH. Evaluation of an in vitro assay system for carcinogens based on prior infection of rodent cells with nontransforming RNA tumor virus. J Natl Cancer Inst 1974; 52:1167-73. [PMID: 4363703 DOI: 10.1093/jnci/52.4.1167] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
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