• Journal of Life Science
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• v.32 no.1
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• pp.11-22
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• 2022

N-methyl-D-aspartate (NMDA) receptors have received considerable attention regarding their involvement in glutamate-induced neuronal excitotoxicity. Resveratrol has been shown to exhibit neuroprotective effects against this kind of overactivation, but the underlying cellular mechanisms are not yet clearly understood. In this study, HT-22 neuronal cells were treated with NMDA in Mg²⁺-free buffer and subsequently used as an experimental model of glutamate excitotoxicity to elucidate the mechanisms of resveratrol-induced neuroprotection. We found that NMDA treatment causes a drop in MTT reduction ability, disrupts inside-negative transmembrane potential of mitochondria, depletes cellular ATP levels, and stimulates intracellular ROS production. Double fluorescence imaging studies demonstrated an increased formation of mitochondrial permeability transition (MPT) pores accompanied by apoptotic cell death, while cobalt protoporphyrin and bilirubin showed protective effects against NMDA-induced mitochondrial injury. On the other hand, zinc protoporphyrin IX significantly attenuated the protective effects of resveratrol which was itself shown to enhance heme oxygenase-1 (HO-1) mRNA and protein expression levels. In cells transfected with HO-1 small interfering RNA, resveratrol failed to suppress the NMDA-induced effects on MTT reduction ability and MPT pore formation. The present study suggests that resveratrol may prevent mitochondrial injury in NMDA- treated HT-22 cells and that enhanced expression of HO-1 is involved in the underlying cellular mechanism.

• Applied Microscopy
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• v.39 no.2
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• pp.117-124
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• 2009

Clonorchis sinensis is the most important widely distributed parasite of the human bile duct in East Asia and the most prevalent parasitic helminth in Korea. The prevalence rate of human clonorchiasis has remained at about 2.9% in Korea. C. sinensis induces dilatation of the duct, hyperplasia of the mucosa, metaplasia or neoplasia of the mucosal epithelium, periductal inflammation and fibrosis, and thickening of the ductal wall. Fibroblast are the most common cells in connective tissue and are responsible for the synthesis of extracellular matrix components. The fibrosis associated with chronic inflammation and injury may also contribute to cholangiocarcinoma pathogenesis, particularly through an increase in extracellular matrix components, which participate in the regulation of bile duct differentiation during development. In this study, ultrastructural changes, the distribution of lectin receptors and actin protein in cultured SD rat bile duct fibroblast after infection of C. sinensis were observed. Experimental group had been divided into four groups: normal bile duct fibroblast cultured in basal media (G1); C. sinensis infected bile duct fibroblast cultured in basal media (G2); normal bile duct fibroblast cultured in basal media containing excretory-secretory product (ESP) (G1-1); C. sinensis infected bile duct fibroblast cultured in basal media containing ESP (G2-1). Overall, once a host is infected by C. sinensis, it affects the host to the extent that sialic acid of ductal fibroblast is increased. Number of cytoplasmic process of SD rat bile duct fibroblast was increased. Actin protein and sialic acid were located in cell surface. Fibroblast induced by C. sinensis was not recovered to normal fibroblast. The cytoplasm bulk and cytoplasmic process were increased whereas the growth rate of the fibroblast of infected SD rat was reduced rather than that of normal fibroblast. In result, it inhibits fibroblast proliferation and increases actin protein on fibroblast cytoplasm, and so causes fibroblast metamorphosis and cellular mutation.

• Tuberculosis and Respiratory Diseases
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• v.48 no.4
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• pp.478-486
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• 2000

Background : In acute lung injury, alveolar macrophages play a pivotal role in the inflammatory process during the initiation phase and in the reconstruction and fibrosis process during the later phase. Recently, it has been proven that alveolar macrophages are constituted by morphologically, biochemically and immunologically heterogenous cell subpopulations. The possibility of alterations to these characteristics of the alveolar macrophage population during lung disease has been raised. To investigate such a possibility a hyperoxic rat lung model was made to check the distributional and morphological changes of rat alveolar macrophage subpopulation in acute hyperoxic lung injury. Method : Alveolar macrophage were lavaged from normal and hyperoxic lung injury rats and separated by discontinuous gradients of percoll. After cell counts of each density fraction were accessed, the morphomeric analysis of alveolar macrophages was performed on cytocentrifuged preparations by transmission electron micrograph. Result : 1. The total alveolar macrophage cell count significantly increased up to 24 hours after hyperoxic challenge (normal control group $171.6{\pm}24.1{\times}10^5$, 12 hour group $194.8{\pm}17.9{\times}10^5$, 24 hour group $207.6{\pm}27.1{\times}10^5$, p<0.05). oHoHH However the 48 hour group ($200.0{\pm}77.8{\times}10^5$) did not show a significant difference. 2. Alveolar septal thickness significantly increased up to 24 hours after hyperoxic challenge(normal control group $0.7{\pm}0.2{\mu}m$, 12 hour group $1.5{\pm}0.4{\mu}m$, 24 hour group $2.3{\pm}0.4{\mu}m$, p<0.05). However the 48 hour group did not show further change ($2.5{\pm}0.4{\mu}m$). Number of interstitial macrophage markedly increased at 24 hour group. 3. Hypodense fraction(fraction 1 and fraction 2) of alveolar macrophage showed a significant increase following hyperoxic challenge ($\beta=0.379$.$\beta=0.694$. p<0.05) ; however, fraction 3 was rather decreased following the hyperoxic challenge($\beta=0.815$. p<0.05), and fraction 4 showed an irregular pattern. 4. Electron microscopic observation of alveolar macrophage from each fraction revealed considerable morphologic heterogeneity. Cells of the most dense subfraction(fraction 4) were small, round, and typically highly ruffled with small membrane pseudopods. Cells of the least dense fraction (fraction 1) were large and showed irregular eccentric nucleus and high number of heterogenous inclusions. Conclusion : In conclusion, these results suggest that specific hypodense alveolar macrophage subpopulation may play a an important role in an acute hyperoxic lung injury model But further study, including biochemical and immunological function of these subpopulations, is needed.

• The korean journal of orthodontics
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• v.37 no.2 s.121
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• pp.89-97
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• 2007

Objective: The purpose of this study was to measure the insertion torque of orthodontic miniscrews regarding changes in their shape, diameter, and length. Methods: Torque values were measured during continuous insertion of the miniscrews into solid rigid polyurethane foam, using a torque tester of driving motor type with a regular speed of 3 rpm. Orthodontic miniscrews (Biomaterials Korea, Seoul, Korea) of cylindrical type and taper type were used. Results: Increasing the length and diameter of the miniscrews increased the maximum insertion torque value in both cylindrical and taper type screws. Insertion torque was increased at the incomplete head of the cylindrical type screw, and at the tapered part of the taper type screw. The insertion torque value of miniscrews was influenced most by diameter, then shape and length. As a result, it was shown that the diameter of the screw had the most influence on insertion torque, and the taper type screw had a higher torque value than the cylindrical type screw. Conclusion: Therefore, a large diameter or taper type screw are adequate for areas of thin cortical bone with a large interdental space, and a small diameter or cylindrical type screw are adequate in the mandibular molar area or the midpalatal area having thick cortical bone.

• Journal of the korean academy of Pediatric Dentistry
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• v.33 no.1
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• pp.91-98
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• 2006

Supernumerary teeth are teeth which result from the continued budding of the enamel organ of the preceding tooth or from excessive proliferation of cells. They are most often found in the maxillary anterior region. And they can be responsible for a variey of irregularities in the primary and transitional dentition. There are two morphological types of supernumerary teeth, supplemental and rudimentary. Supplemental teeth have normal shape and size. In contrast, rudimental teeth have abnormal shape and smaller size. Supplemental supernumerary teeth are most common in permanent lateral incisor area. Its extraction must be decided more carefully with differential diagnosis between normal teeth, because it has normal shape and size. We reports 3 cases of the normal incisor shaped teeth in the maxillary anterior region. In all cases, we used the 3D Dental-CT as well as the conventional plain film such as periapical, occlusal, and panoramic radiograph. Consequently, 3B Dental-CT was valualble to figure out the exact position and morphology of supernumerary teeth, to do more conservative surgery and to reduce surgery stress and time.

• Applied Microscopy
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• v.37 no.4
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• pp.219-230
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• 2007

The morphological effects of intranasal zinc sulfate(5% solution) irrigation on the mouse olfactory epithelium and the regeneration process of olfactory receptor cells following nasal irrigation were studied with scanning and transmission electron microscope. The results were as follows: 1. The septal epithelium except some basal cells was wholly detached from the basement membrane, during the first 6 to 24 hours after 5% zinc sulfate irrigation. 2. 3 days after $ZnSO_4$ treatment, two layered septal epithelium was formed from basal cells. And microvilli were observed in the apical epithelium of newly formed olfactory epithelial cells. 3. 5 days after treatment, a lot of centrosomes and basal bodies were observed in the olfactory receptor cells, and cilia were lined up between microvilli on the apical membrane of olfactory receptor cells. And immature olfactory knob was first observed in the newly formed olfactory receptor cells. Mature olfactory knob was observed 1 week after treatment. 4. There are very many mature olfactory knobs in the olfactory receptor cells 2 weeks after intranasal zinc sulfate irrigation. These results support that treatment with 5% zinc sulfate is a good experimental model for the regeneration of mammalian nervous tissues because this method could thoroughly detach the septal epithelium. During the regeneration of olfactory receptor cells, the surface membrane of the olfactory receptor cells widen the surface with the microvilli. Then cilia, which arranged in a line, substituted for the microvilli. The part of the surface membrane with cilia protruded and finally formed the olfactory vesicle.

• Ocean and Polar Research
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• v.34 no.2
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• pp.137-149
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• 2012

Hemocyte parameters of the wild Pacific oyster Crassostrea gigas inhabiting intertidal zones in small bays (Gwangyang and Jinhae Bay) on the southern coast of Korea were evaluated using flow cytometry and neutral red retention (NRR) assay. Morphological features, cell count, mortality, DNA damage, phagocytosis, and lysosomal membrane stability of hemocytes were analyzed. Three types of hemocytes were identified in the oyster hemolymph: granulocytes, hyalinocytes, and blast-like cells. Immune related functions of hemocyte including phagocytosis and lysosomal membrane stability were significantly different among the study areas (P<0.05), while cell count, mortality, and DNA damage of hemocytes were not significantly different. In Gwangyang Bay, phagocytosis of granulocytes and lysosomal membrane stability of oyster hemocytes inhabiting inside bay were significantly lower than those of oyster hemocytes in outside bay (P<0.05), indicating that oysters in inside bay of Gwangyang were relatively suppressed the immunological function in hemocytes. Contrary to Gwangyang Bay, immune parameters of oyster hemocytes in Jinhae Bay not showed the difference between sampling sites. In conclusion, flow cytometry and NRR assay using oyster hemocyte has a powerful tool to investigate the cell level in a short time due to no-preprocessing of material.

• The Korean Journal of Food And Nutrition
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• v.23 no.1
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• pp.30-38
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• 2010

This study was conducted to determine the effects of vitamin C on the activity of liver function enzymes and electromicrographic changes in white rats treated with aflatoxin $B_1(AFB_1)$ or X-ray and $AFB_1$. Six week-old male Sprague-Dawley rats were randomly divided into five groups: a control group, $AFB_1$ treated group, $AFB_1$ treated group with vitamin C, X-ray and $AFB_1$ co-treated group, X-ray and $AFB_1$ co-treated group with vitamin C. On the first day of the experiment, only one dose of X-rays was exposed to the entire liver at 1,500 cGy. Next, vitamin C was injected at 10 mg/kg body weight by intraperitoneal injection, followed 1 hr later by the administration of 0.4 mg/kg of $AFB_1$ by intraperitoneal injection. These treatments were then administered every three days over a period of 15 days. On the 16th day of treatments, the animals were sacrificed. Analysis of the activity of the liver function enzymes, GOT, ALK phatase and LDH, in the sera of rats revealed that they were somewhat increased by $AFB_1$ treatment, X-ray and $AFB_1$ co-treatment when compared to the control group. Furthermore, the activity of these enzymes decreased in response to administration of vitamin C. Especially, the levels of GOT were remarkably decreased in the $AFB_1$ treated group treated with vitamin C when compared to the group treated with $AFB_1$ alone(p<0.001). Electromicrographic analysis revealed cloudy swelling, necrosis, vesicular degeneration and fat accumulation of hepatocytes in response to treatment with $AFB_1$ or co-treatment with X-ray and $AFB_1$. However, the destruction of hepatic cells was considerably lower in the vitamin C-treated group. These results indicate that vitamin C had ameliorating effects on the hepatic cell damage.

• Journal of Chest Surgery
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• v.43 no.2
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• pp.194-198
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• 2010

Intramural hematoma of the aorta (IMH) is the precursor or a variant of a classic aortic dissection where hemorrhage occurs within the aorta wall in the absence of an initial intimal tear. IMH has a high rate of mortality and morbidity. The optimal therapy for IMH is uncertain, yet the involvement of the ascending aorta is usually considered as an indication for surgery due to the associated risk of rupture or cardiac tamponade. We report here on a case of a 71-year-old man who presented with syncope. Because of misdiagnosis, he underwent computed tomography (CT) after 5 hrs from arriving to the ER. Computed tomography of the aorta revealed intramural hematoma of the ascending aorta with cardiac tamponade. He also had vascular complications such as acute renal failure and visceral ischemia. We performed emergency graft replacement of the total arch and ascending aorta. He was discharged without complication on postoperative day 14.

• Journal of Life Science
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• v.24 no.1
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• pp.98-103
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• 2014

NAD(P)H quinone oxidoreductase 1 (NQO1) is a flavoprotein that catalyzes the two electron reduction of diverse substrates, including quinones. It uses NADH or NADPH as a cofactor for enzymatic machinery. In the metabolism of quinones, NQO1 has two conflicting functions because of the different stability of converted hydroquinones. The stable form of hydroquinone is excreted from cells by conjugation with glutathione or glucuronic acid. The unstable form of hydroquinone induces cell death by induction of oxidative stress and DNA damage. Certain quinones known as bio-reductive agents have a cytotoxic function following reduction by NQO1. Bio-reductive agents, such as ${\beta}$-lapachone or mitomycin C, induce the depletion of NAD(P)H and the generation of oxidative stress in an NQO1-dependent manner. NQO1 is highly expressed in several cancer tissues. Therefore, NQO1 is a good therapeutic target for cancer treatment with bio-reductive agents.