• Nutrition Research and Practice
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• v.9 no.2
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• pp.117-122
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• 2015

BACKGROUND/OBJECTIVES: Curcumin, a major component of the Curcuma species, contains antioxidant and anti-inflammatory properties. Although it was found to induce apoptosis in cancer cells, the functional role of curcumin as well as its molecular mechanism in anti-inflammatory response, particularly in intestinal cells, has been less investigated. The intestine epithelial barrier is the first barrier and the most important location for the substrate coming from the lumen of the gut. SUBJECTS/METHODS: We administered curcumin treatment in the human intestinal epithelial cell lines, T84 and Caco-2. We examined endoplasmic reticulum (ER) stress response by thapsigargin, qPCR of XBP1 and BiP, electrophysiology by wild-type cholera toxin in the cells. RESULTS: In this study, we showed that curcumin treatment reduces ER stress and thereby decreases inflammatory response in human intestinal epithelial cells. In addition, curcumin confers protection without damaging the membrane tight junction or actin skeleton change in intestine epithelial cells. Therefore, curcumin treatment protects the gut from bacterial invasion via reduction of ER stress and anti-inflammatory response in intestinal epithelial cells. CONCLUSIONS: Taken together, our data demonstrate the important role of curcumin in protecting the intestine by modulating ER stress and inflammatory response post intoxication.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.1
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• pp.51-56
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• 1999

This paper presents a new transient overvoltage blocking device (TOBD) for info-communication facilities with low power and high frequency bandwidth. Conventional protection devices have some problems such as low frequency bandwidth, low energy capacity and high remnant voltage. In order to improve these limitations, thehybrid type TOBD, which consists of a gas tube, avalanche diodes and junction typefield effect transistors (JFETs), was designed and fabricated. The TOBD differs from the conventional protection devices in configuration, and JFETs were used as an active non-linear element and a high speed switching diode with low capacitance limits high current. Therefore the avalanche dilde with low energy capacity are protected fromthe high current, and the TOBD has a very small input capacitance. From the performance test using combination surge generator, which can produce $1.2/50\mus\;4.2kV_{max}\; 8/20\mus\; 2.1kA_{max}$, it is confirmed that proposed TOBD has an excellent protection performance in tight clamping voltage and limiting current characteristics.

• Reproductive and Developmental Biology
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• v.40 no.2
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• pp.23-26
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• 2016

Transcription factor called activating enhancer binding protein 2C (AP2-gamma) is found in a variety of species and expressed from oocyte stage onwards, particularly restricted to the trophectoderm. Recent studies demonstrated that ablation of Tfap2c led to failure of tight junction biogenesis, particularly the knock-down embryos of Tfap2c did not form cavity from morula to blastocyst in mouse and pig. We speculated that the Tfa2pc may also be involved in desmosome biogenesis because blastocoel formation is coincident with the establishment of desmosome. To determine this, we depleted Tfap2c injecting siRNA into one-cell zygote and analysed the expression levels of genes that are required for desmosome complex such as PkP2, Pkp3, Dsc2, and Dsg2. We found only Pkp3 was up-regulated in the knockdowned morula embryos. Interestingly, upstream region of Pkp3 had putative Tfap2c binding sites. In conclusion, our results suggest that Tfap2c is not a crucial factor but somehow it might be involved in desmosome biogenesis directly or indirectly via Pkp3.

• Korean Journal of Veterinary Research
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• v.56 no.2
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• pp.57-66
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• 2016

The gut epithelial barrier, which is composed of the mucosal layer and the intestinal epithelium, has multiple defense mechanisms and interconnected regulatory mechanisms against enteric microbial pathogens. However, many bacterial pathogens have highly evolved infectious stratagems that manipulate mucin production, epithelial cell-cell junctions, cell death, and cell turnover to promote their replication and pathogenicity in the gut epithelial barrier. In this review, we focus on current knowledge about how bacterial pathogens regulate mucin levels to circumvent the epithelial mucus barrier and target cell-cell junctions to invade deeper tissues and increase their colonization. We also describe how bacterial pathogens manipulate various modes of epithelial cell death to facilitate bacterial dissemination and virulence effects. Finally, we discuss recent investigating how bacterial pathogens regulate epithelial cell turnover and intestinal stem cell populations to modulate intestinal epithelium homeostasis.

• Development and Reproduction
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• v.25 no.1
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• pp.1-14
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• 2021

The Syrian (golden) hamsters are seasonal breeders whose reproductive functions are active in summer and inactive in winter. In experimental facility mimicking winter climate, short photoperiod (SP) induces gonadal regression. The blood-testis barrier (BTB) of the sexually involuted animals have been reported to be permeable, allowing developing germ cells to be engulfed or sloughed off the epithelium of the seminiferous tubules. The expressions of genes related to the tight junction composing of BTB were investigated in the reproductive active and inactive testes. Claudin-11, occludin, and junctional adhesion molecule (JAM) were definitely expressed in the active testes but not discernably detected in the inactive testes. And spermatozoa (sperm) were observed in the whole lengths of epididymides in the active testes. They were witnessed in only cauda region of the epididymides but not in caput and corpus regions in animals with the inactive testes. The results imply that the disorganization of BTB is associated with the testicular regression. The developing germ cells are swallowed into the Sertoli cells or travel into the lumen, as supported by the presence of the sperm delayed in the last region of the epididymis. These outcomes suggest that both apoptosis and desquamation are the processes that eliminate the germ cells during the regressing stage in the Syrian hamsters.

• Journal of Microbiology and Biotechnology
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• v.31 no.11
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• pp.1568-1575
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• 2021

Obesity and related metabolic diseases are major problems worldwide. Some probiotics are currently considered potential therapeutic strategies for obesity. We aimed to investigate the anti-obesity efficacy of Latilactobacillus sakei WIKIM31 in obese mice induced by a high fat diet. The administration of a high-fat diet with L. sakei WIKIM31 reduced body weight gain, epididymal fat mass, triglyceride and total cholesterol levels in the blood, and remarkably decreased the expression of lipogenesis-related genes in the epididymal adipose tissue and liver. Interestingly, intake of L. sakei WIKIM31 improved gut barrier function by increasing the gene expression of tight junction proteins and suppressing the inflammatory responses. Additionally, L. sakei WIKIM31 enhanced the production of short-chain fatty acids, such as butyrate and propionate, in the intestinal tract. These results showed that L. sakei WIKIM31 can be used as a potential therapeutic probiotic for obesity.

• Applied Microscopy
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• v.16 no.2
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• pp.1-13
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• 1986

The purpose of this study was to investigate the morphology and intercellular junctions of the odontoblast of dental pulp in the rat incisor by means of the freeze fracture electron microscopy. Twenty male Sprague-Dawley rats weighing $150{\sim}200g$ were used. After being anesthetized by an intraperitoneal injection of 0.5 ml sodium pentobarbital per kg in body weight(60 mg/ml) the animals were perfused with 2.5% glutaraldehyde-2% paraformaldehyde fixative in 0.1 M cacodylate buffer, pH 7.2 through the ascending aorta for one hour. The incisors were carefully extracted from the jaws and demineralized by suspending them in 0.1 M EDTA in 3% glutaraldehyde (pH 7.2) for two weeks. After demineralization, the specimens were obtained from the portion divided into five equal parts. For freeze-fracture replication, demineralized tissues were infiltrated for several hours with 10%, 25% glycerol in 0.1M cacodylate buffer as a cryoprotectant and then frozen in liquid Freon 22 and stored in liquid nitrogen. Fracturing and replication were done in Balzers BAF 400D high-vacuum freeze-fracture apparatus at $-120^{\circ}C$ under routine $5X10^{-7}$ Torr vacuum. The tissue was immediately replicated with platinum unidirectionally at $45^{\circ}$ angle and reinforced with carbon at $90^{\circ}$ angle unidirectionally or by using a rotary stage. The replication process was monitored by a quartz-crystal device. The replicas were immersed in 100% methanol overnight. The tissue was then digested from the replica by clorox (laundry bleach), placed into 5% EDTA, and washed repeatedly with distilled water. The replicas were picked up on 0.3% formvar-coated 75 mesh grids and examined in the JEOL 100B electron microscope. The results were as follows; 1. Both in thin sections and freeze-fracture replicas, three types of intercellular junctions were recognizable in the plasma membrane of odontoblast: gap junction, tight junction and desmosome-like junction. 2. The nuclear pores were evenly distributed over the nuclear envelope. The pore complex formed a ring about 70 nm in diameter. 3. Gap junctions were found between odontoblasts as well as odontoblasts and neighbouring pulp cells (fibroblast, subodontoblastic cell process, nerve-like fibre). Gap junctions, which were round, ellipsoid and pear-shaped and 600 nm in diameter, were observed in the odontoblast. 4. Numerous round and ellipsoid gap junctions could be frequently seen on the plasma membranes in cell body and apical part of the odontoblasts. On the P face, the junctions were recognized as a cluster of closely packed particles, measuring about 9 nm in diameter, and on the E face, the junctions were recognized as a shallow grooves.

• Applied Microscopy
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• v.31 no.2
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• pp.157-165
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• 2001

Sertoli cells in the normal adult testis are nondividing cells, which are relatively inconspicuous on cross section of the seminiferous tubule and comprise about 10% to 15% of the tubular cellular elements. Ultrastructurally, Sertoli cells have characteristic nucleoli, plasma membrane, and cytoplasmic components. The plasma membrane has two types of intercellular junctions which are developed at puberty: junctions between adjacent Sertoli cells and Sertoli cell-germ ceil junction. However, the ultrastructural findings of Sertoli cells in human fetus is not fully elucidate yet. In the present study, human fetal testes ($14\sim27$ weeks) obtained from artificially induced abortions legally without gross malformation were studied using transmission electron microscopy to make clear the differentiation process of Sertoli cells in human. In human fetal testes from 14 weeks to 27 weeks, the cell junctions of Sertoli-germ cells and Sertoli-Sertoli cells are desmosome like structure and not tight junction or desmosome. The Overall intracytoplasmic organelles of Sertoli cells are relatively sparse. The mitochondrias are relatively abundant but no developed cristae. And the rough endoplasmic reticuli are abundant and smooth endoplasmic reticuli are sparse. The amount of lipid droplets are regularly observed in human fetal Sertoli cells. No microfilaments or Charcot-Bottcher's crystalloids are present. From the results, Sertoli cells in human fetal testes are somewhat different ultrastructural findings with puberty or adult. However, to make clear the differentiation process of Sertoli cells in human, further study for 28 weeks to puberty is required.

• Journal of Gastric Cancer
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• v.20 no.4
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• pp.408-420
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• 2020

Purpose: Isoform 2 of tight junction protein claudin-18 (CLDN18.2) is a potential target for gastric cancer treatment. A treatment targeting CLDN18.2 has shown promising results in gastric cancer. We investigated the clinical significance of CLDN18.2 and other cell-adherens junction molecules (Rho GTPase-activating protein [RhoGAP] and E-cadherin) in metastatic diffuse-type gastric cancer (mDGC). Materials and Methods: We evaluated CLDN18.2, RhoGAP, and E-cadherin expression using two-plex immunofluorescence and quantitative data analysis of H-scores of 77 consecutive mDGC patients who received first-line platinum-based chemotherapy between March 2015 and February 2017. Results: CLDN18.2 and E-cadherin expression was significantly lower in patients with peritoneal metastasis (PM) than those without PM at the time of diagnosis (P=0.010 and 0.013, respectively), whereas it was significantly higher in patients who never developed PM from diagnosis to death than in those who did (P=0.001 and 0.003, respectively). Meanwhile, CLDN18.2 and E-cadherin expression levels were significantly higher in patients with bone metastasis than in those without bone metastasis (P=0.010 and 0.001, respectively). Moreover, we identified a positive correlation between the expression of CLDN18.2 and E-cadherin (P<0.001), RhoGAP and CLDN18.2 (P=0.004), and RhoGAP and E-cadherin (P=0.001). Conversely, CLDN18.2, RhoGAP, and E-cadherin expression was not associated with chemotherapy response and survival. Conclusions: CLDN18.2 expression was reduced in patients with PM but significantly intact in those with bone metastasis. Furthermore, CLDN18.2 expression was positively correlated with other adherens junction molecules, which is clinically associated with mDGC and PM pathogenesis.

• The Journal of Internal Korean Medicine
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• v.37 no.1
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• pp.65-76
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• 2016

Objectives: The purpose of this study was to identify the inhibitory effects of Hwangheuk-san (HHS), a Korean multi-herb formula comprising four medicinal herbs, on cell migration and invasion, two critical cellular processes that are often deregulated during metastasis, using the human bladder cancer 5637 cell line.Methods: Cell viability, motility, and invasion were assessed by 3-(4,5-dimethyl-2 thiazolyl)-2,5-diphnyl-2H-tetrazolium bromide (MTT), wound healing migration, and Transwell assays, respectively. Gene expression was detected by Western blot analysis. In addition, the activities of matrix metalloproteinases (MMPs) and the values for transepithelial electrical resistance (TER) were analyzed using a Gelatinase Activity Assay Kit and an Epithelial Tissue Voltohmmeter, respectively.Results: Our data indicated that within the concentration range that was not cytotoxic, HHS effectively inhibited the cell motility and invasiveness of 5637 cells. HHS markedly decreased the expression and activity of MMP-2 and MMP-9, which was associated with unregulation of tissue inhibitors of metalloproteinase (TIMP)-1 and TIMP-2. Further investigation revealed that phosphorylation of phosphatidylinositol 3-kinase (PI3K) and AKT was decreased in HHS-treated 5637 cells, and a PI3K/AKT inhibitor synergistically reduced the inhibition of migration and invasion and also inactivated MMP-2 and MMP-9. Moreover, HHS increased the tightening of tight junctions (TJs), which was demonstrated by an increase in the TER, and reduced the expression the levels of claudin family members (claudin-3 and -4), which are major components involved in the tightening of TJs.Conclusions: The present findings demonstrated that HHS attenuated the migration and invasion of bladder cancer 5637 cells by modulating the activity of the PI3K/Akt signaling pathway and also through TJ tightening.