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Featured researches published by Sunhwa Hong.


Cell Biology and Toxicology | 2002

Degradation of IκBα in Activated RAW264.7 Cells is Blocked by the Phosphatidylinositol 3-Kinase Inhibitor LY294002

Seong-Hoon Park; Si-Woo Lee; Sunhwa Hong; H.M. Kim

The mechanism by which lipopolysaccharide (LPS) or phorbol 12-myristate 13-acetate (PMA) induces production of proinflammatory cytokines in murine macrophages, and the role of phosphatidylinositol 3-kinase (PI3-kinase) have not been well investigated. Activation of nuclear factor κB (NF-κB) is initiated by the phosphorylation of the inhibitory subunit, IκB, which targets IκB for degradation and leads to the release of active NF-κB. In this study we demonstrate that 2- (4-morpholinyl)-8-phenylchromone (LY294002), which inhibits PI3-kinase, specifically inhibited degradation of IκBα in RAW264.7 cells stimulated with interferon-γ (IFN-γ) plus LPS or IFN-γ plus PMA. To elucidate the importance of this activity in RAW264.7 cells, we examined tumor necrosis factor-α (TNF-α) and interleukin IL)-6 production in the activated cells. Pretreatment of the cells with LY294002 resulted in the inhibition of TNF-α and IL-6 production in RAW264.7 cells stimulated with IFN-γ plus LPS or IFN-γ plus PMA. Furthermore, LY294002 inhibited the production of nitric oxide NO) in RAW264.7 cells stimulated with IFN-γ plus LPS or IFN-γ plus PMA. LY294002 also inhibited inducible NO synthase (iNOS) mRNA expression in the activated RAW264.7 cells. In conclusion, the present results suggest that PI3-kinase is involved in the signal transduction pathway responsible for LPS- or PMA-mediated TNF-α and IL-6 production, and that LY294002 inhibits NO generation through blocking the degradation of IκBα in activated RAW264.7 cells.


Laboratory Animal Research | 2012

Molecular identification of Mycoplasma cynos from laboratory beagle dogs with respiratory disease.

Sunhwa Hong; Okjin Kim

In this study, we examined a colony of 20 beagle dogs in a laboratory animal facility. Mycoplasma was detected by consensus PCR assay in 1 dog with respiratory and constitutional symptoms. None of the other dogs were affected. The dog was euthanized and necropsied. In postmortem examinations, gray or plum-colored gross lesions were found on the lung, most commonly in the apical and cardiac lobes. Some lesions showed clear demarcation and consolidation. Microscopic examination showed peribronchiolar lymphoid hyperplasia and interstitial thickening, lesions pathognomonic for mycoplasma pneumonia. To identify canine Mycoplasma species, we used species-specific PCR reactions for M. arginini, M. canis, M. cynos, M. edwardii, M. felis, M. gateae, M. maculosum, M. molare, M. opalescens, M. spumans, Mycoplasma sp. HRC 689, and M. collis. As the result, we identified Mycoplasma cynos by amplification of DNA extracted from lung tissue of the laboratory beagle dog with respiratory disease.


Laboratory Animal Research | 2011

Sensitive and Specific Detection of Mycoplasma species by Consensus Polymerase Chain Reaction and Dot Blot Hybridization

Sunhwa Hong; Hyun-A Lee; Sang-Ho Park; Okjin Kim

Mycoplasmas are highly fastidious bacteria, difficult to culture and slow growing. Many species of mycoplasmas are important pathogens that cause respiratory infection in laboratory animals and that are known to affect experimental results obtained with contaminated animals. The aim of the present study was to develop a sensitive and specific assay for the detection of mycoplasma species. To this end, we developed a polymerase chain reaction and dot blot hybridization assay (PCR/DBH) for detecting mycoplasma DNA and evaluated it for its sensitivity and specificity. Mycoplasma consensus primer pairs were used for the amplification of target DNA. When PCR product was visually detected, the limit of detection of the PCR test was 102 pg of mycoplasma purified DNA. For DBH, the amplified DNA was labeled by incorporation of digoxigenin (DIG). This DIG-labeled probe was capable of detecting 104 pg of purified mycoplasma DNA by DBH. PCR/DBH was more sensitive than PCR or DBH alone and was also very specific. Our PCR/DBH assay can be applied efficiently to confirm the presence of mycoplasma species on clinical samples and to differentiate between mycoplasma species infection and other bacterial infections.


Laboratory Animal Research | 2011

Cronobacter sakazakii Infection Induced Fatal Clinical Sequels Including Meningitis in Neonatal ICR Mice

Hyun-A Lee; Sunhwa Hong; Hyoseok Park; Hoikyung Kim; Okjin Kim

Cronobacter sakazakii (C. sakazakii), formerly Enterobacter sakazakii, is an emerging pathogen associated with the ingestion of contaminated reconstituted formula that causes serious illnesses such as bacteremia, septicemia, necrotizing enterocolitis, meningitis and death in low-birth-weight preterm neonatal infants. The objective of this study was to develop an animal model for human neonatal C. sakazakii infections. We acquired timed-pregnant ICR mice and allowed them to give birth naturally. On postnatal day 3.5, each pup was administered orally a total dose of approximately 107 CFU C. sakazakii strain 3439. Mice were observed twice daily for morbidity and mortality. At postnatal day 10.5, the remaining pups were euthanized, and brain, liver, and cecum were excised and analyzed for the presence of C. sakazakii. C. sakazakii was isolated from cecum and other tissues in inoculated mice. In the tissues of C. sakazakii infected mice, meningitis and gliosis were detected in brain. In this study, we confirmed the neonatal ICR mice may be used a very effective animal model for human neonatal C. sakazakii infections.


Laboratory Animal Research | 2011

Sensitive and specific identification by polymerase chain reaction of Eimeria tenella and Eimeria maxima, important protozoan pathogens in laboratory avian facilities.

Hyun-A Lee; Sunhwa Hong; Yung-Ho Chung; Okjin Kim

Eimeria tenella and Eimeria maxima are important pathogens causing intracellular protozoa infections in laboratory avian animals and are known to affect experimental results obtained from contaminated animals. This study aimed to find a fast, sensitive, and efficient protocol for the molecular identification of E. tenella and E. maxima in experimental samples using chickens as laboratory avian animals. DNA was extracted from fecal samples collected from chickens and polymerase chain reaction (PCR) analysis was employed to detect E. tenella and E. maxima from the extracted DNA. The target nucleic acid fragments were specifically amplified by PCR. Feces secreting E. tenella and E. maxima were detected by a positive PCR reaction. In this study, we were able to successfully detect E. tenella and E. maxima using the molecular diagnostic method of PCR. As such, we recommended PCR for monitoring E. tenella and E. maxima in laboratory avian facilities.


Laboratory Animal Research | 2011

Uterine adenocarcinoma with feline leukemia virus infection

Sung-Jin Cho; Hyun-A Lee; Sunhwa Hong; Okjin Kim

Feline endometrial adenocarcinomas are uncommon malignant neoplasms that have been poorly characterized to date. In this study, we describe a uterine adenocarcinoma in a Persian cat with feline leukemia virus infection. At the time of presentation, the cat, a female Persian chinchilla, was 2 years old. The cat underwent surgical ovariohystectomy. A cross-section of the uterine wall revealed a thickened uterine horn. The cat tested positive for feline leukemia virus as detected by polymerase chain reaction. Histopathological examination revealed uterine adenocarcinoma that had metastasized to the omentum, resulting in thickening and the formation of inflammatory lesions. Based on the histopathological findings, this case was diagnosed as a uterine adenocarcinoma with abdominal metastasis. To the best of our knowledge, this is the first report of a uterine adenocarcinoma with feline leukemia virus infection.


Laboratory Animal Research | 2011

Spontaneous osteosarcoma of the femur in a non-obese diabetic mouse.

Sunhwa Hong; Hyun-A Lee; Ohmok Choe; Youngho Chung; Okjin Kim

An abnormal swelling was identified in the distal portion of the right femur in a 1-year-old non-obese diabetic (NOD) mouse. Grossly, a large mass of the distal femur was observed in the right femur. Lesions were poorly marginated, associated with destruction of the cancellous and cortical elements of the bone, and showed ossification within the soft tissue component. Histologically, the tumor was identified as a poorly differentiated sarcoma. Histopathologic examination of the bone masses revealed invasive proliferation of poorly differentiated neoplastic mesenchymal cells forming streams, bundles, and nests, which resulted in destruction of normal bone. Neoplastic cells exhibited random variation in cellular appearance and arrangement, as well as matrix composition and abundance. Haphazard and often intermingling patterns of osteogenic, chondroblastic, lipoblastic, and angiogenic tissues were present. Larger areas of neoplastic bone and hyaline cartilage contained multiple large areas of hemorrhage and necrosis bordered by neoplastic cells. The mass was diagnosed as an osteosarcoma. To our knowledge, this is the first spontaneous osteosarcoma in an NOD mouse.


Laboratory Animal Research | 2013

Usefulness of a Helicobacter pylori stool antigen test for diagnosing H. pylori infected C57BL/6 mice

Dae-In Moon; Eun-Hye Shin; Hong-Geun Oh; Jinsik Oh; Sunhwa Hong; Yung-Ho Chung; Okjin Kim

Among several diagnostic tests, a Helicobacter pylori stool antigen (HpSA) test may offer a useful noninvasive method for diagnosing infection without sacrificing animals. In this study, male C57BL/6 mice (n=6) were infected with H. pylori ATCC 49503 (1×108 CFU/mouse) by intragastric inoculation three times at 2-day intervals, and H. pylori infected stool specimens were collected 1, 3, 5, 7, 14, 21 days after infection to assess reliability of the HpSA test. Five of six specimens were positive at 5-21 days after infection, and the sensitivity of the HpSA test was 83.33%. The presence of H. pylori infection was confirmed by the rapid urease test and genomic DNA polymerase chain reaction (PCR), and showed the same results as the HpSA. However, the rapid urease test and genomic DNA PCR are invasive tests and require animal sacrifice to detect H. pylori in gastric biopsy samples. We suggest that an HpSA test kit would be useful and effective for monitoring H. pylori in various laboratory animals, as H. pylori can be easily monitored without sacrificing animals.


Laboratory Animal Research | 2011

Mural folliculitis and alopecia with cutaneous candidiasis in a beagle dog.

Hyun-A Lee; Sunhwa Hong; Ohmok Choe; Okjin Kim

A one-year-old male Beagle dog showed dermatitis, alopecia and scales. Examination of the affected dog revealed generalized alopecia, patchy erythema, and superficial erosions with histological evidence of mural folliculitis. External tests for parasites in scraped skin samples were negative. However, fungal culture tests and polymerase chain reaction revealed the existence of Candida in the lesion. These results suggest that cutaneous candidiasis may induce mural folliculitis and alopecia in dogs.


Laboratory Animal Research | 2011

Spontaneous Sertoli Cell Tumor with Cryptorchism in a Beagle Dog

Sunhwa Hong; Hyun-A Lee; Sang-Jun Han; Okjin Kim

A male one year-old beagle dog with unilateral cryptorchism was presented for investigation of reduced appetite. Abdominal sonography and radiography demonstrated abnormal enlargement of the left testicle in the abdominal cavity. Both the retroperitoneal cryptorchid testicle and the other contralateral testicle were removed surgically. The retroperitoneal cryptorchid testicle was an enlarged, firm and bulging sphere mass. The cut surface revealed a homogeneous white color. The contralateral testicle in the scrotum showed an almost normal appearance. Histopathologically, the retroperitoneal cryptorchid testicle was diagnosed as a Sertoli cell tumor. This report describes a case of Sertoli cell tumor with cryptorchism in a beagle dog.

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Okjin Kim

Seoul National University

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Sang-Ho Park

Soonchunhyang University

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Min Sun Kim

Chonbuk National University

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Hak-Yong Lee

Chonbuk National University

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