Development and Application of E-Learning Human Anatomy Content for Undergraduate Students in Health Allied Science / 체질인류학회지

This study aimed to develop and implement a progressive e-learning teaching method in the teaching of human anatomy. For analysis of the effect of new teaching methods, we made a survey of user satisfaction, content difficulty, and course management. The e-learning content was developed by the authors and implemented to class, practice, and tests, for 16 weeks. The survey was conducted on sophomores of nursing science (NS, n=42) and sports science (SS, n=26), at Kangwon National University. These two groups of students filled out a questionnaire related to effectiveness of e-learning content and tool in learning human anatomy. The results were compared between two groups. The majority of the students were satisfied with the content, difficulty level, and management of the e-learning course. Through the board of virtual classroom, all of the students played positive manners in communication and activity. Students pointed out 'reinforcement of multimedia data', 'improvement of technical service' and 'addition of broad information' as the most notable improvements of content. Therefore, we conclude that an e-learning course for undergraduate nursing science and sports science students can provide an effective learning model.

CD98 activation increases surface expression and clusteringof beta 1 integrins in MCF-7 cells through FAK/Src- and cytoskeleton-independent mechanisms

CD98, a disulfide-linked 125-kDa heterodimeric type II transmembrane glycoprotein, regulates beta 1 integrin- mediated cell adhesion. However, the molecular mechanisms underlying CD98-mediated activation of beta 1 integrin are presently unclear. In this study, the effects of CD98 signaling on the expression and clustering of beta 1 integrin were investigated. Activation of CD98 augmented surface expression of beta 1 integrin on MCF-7 cells. Cross-linking CD98 induced clustering of beta 1 integrins. Inhibition of phosphorylation of focal adhesion kimase (FAK) by PP2, an inhibitor of Src family kinase, reduced cell-extracellular matrix adhesion, but not surface expression and clustering of beta1 integrin on MCF-7 cells. This result was confirmed by over-expression of dominant negative forms of FAK. In addition, phalloidin or cytochalasin D inhibited CD98-mediated induction of cell-ECM adhesion, but not surface expression and clustering of b1 integrins. The inhibitory effects of PP2, cytochalasin D or phalloidin on CD98-stimulated cell adhesion were diminished by pretreatment of cells with Mn2+, which is shown to induce conformational change of integrins. These results provide the first evidence that CD98 activation increases not only beta1 integrin affinity but also its surface expression and clustering and the latter is independent of FAK/Src and cytoskeleton.

CD36 signaling inhibits the translation of heat shock protein 70 induced by oxidized low density lipoprotein through activation of peroxisome proliferators-activated receptor gamma

Oxidized LDL (OxLDL), a causal factor in atherosclerosis, induces the expression of heat shock proteins (Hsp) in a variety of cells. In this study, we investigated the role of CD36, an OxLDL receptor, and peroxisome proliferator-activated receptor gamma (PPAR gamma) in OxLDL-induced Hsp70 expression. Overexpression of dominant-negative forms of CD36 or knockdown of CD36 by siRNA transfection increased OxLDL-induced Hsp70 protein expression in human monocytic U937 cells, suggesting that CD36 signaling inhibits Hsp70 expression. Similar results were obtained by the inhibition of PPAR gamma activity or knockdown of PPAR gamma expression. In contrast, overexpression of CD36, which is induced by treatment of MCF-7 cells with troglitazone, decreased Hsp70 protein expression induced by OxLDL. Interestingly, activation of PPAR gamma through a synthetic ligand, ciglitazone or troglitazone, decreased the expression levels of Hsp70 protein in OxLDL-treated U937 cells. However, major changes in Hsp70 mRNA levels were not observed. Cycloheximide studies demonstrate that troglitazone attenuates Hsp70 translation but not Hsp70 protein stability. PPAR gamma siRNA transfection reversed the inhibitory effects of troglitazone on Hsp70 translation. These results suggest that CD36 signaling may inhibit stress- induced gene expression by suppressing translation via activation of PPAR gamma in monocytes. These findings reveal a new molecular basis for the anti-inflammatory effects of PPAR gamma.

Tissue Transglutaminase Activates NF-kappaB Pathway in the Atherosclerotic Coronary Artery / 체질인류학회지

Molecular mechanism of nuclear factor-kappaB(NF-kappaB) in the atherosclerosis has been unclear. Recently, NF-kappaB activating function of tissue transglutaminase (tTGase), multifunctional calcium-dependent transamidation enzyme, have been reported in the various tissues like neuroglia. In this report, we investigated the immunoreactivity of tTGase at the human atherosclerotic coronary artery, and examined the effect of tTGase on the well-known proatherogenic NF-kappaB pathway using tTGase-overexpressed cells. Immunohistochemical studies on autopsy samples showed that immunoreactivity of tTGase was markedly elevated in the neointimal tissues of atherosclerotic coronary arteries with progression of disease. Immunohistochemical staining also demonstrated that phosphorylated I-kappaB was activated in the atherosclerotic vessel wall. In vitro study using rat cardiomyoblast (H9c2) and tTGase-overexpressed H9c2 showed that activated tTGase enhanced the phosphorylation of I-kappaB, and this activation was inhibited by tTGase specific inhibitors. These findings suggest that cytosolic tTGase may serve as an activator of NF-kappaB.

Application of Integrative Lecturing to Basic Medicine Courses for Undergraduate Health Allied Sciences Students / 한국의학교육

PURPOSE: In spite of the rapidly expanding importance of the basic sciences, the number of professors teaching basic sciences in medicine has not changed in the last decade. Thus, the need for new methods of teaching and learning has increased. The purpose of this study was to develop and assess integrative lecturing in the basic sciences for undergraduate allied health sciences students. METHODS: We developed an alternate form of lecturing in anatomy, physiology, microbiology, and pathology, focusing on the gastrointestinal system. We tested several teaching strategies including E-learning, face-to-face, and practice. Students majoring in nursing (n=43), sports science (n=26), and emergency medical technology (n=35) participated and were asked to complete an anonymous survey. RESULTS: The majority of the students were satisfied with the new lecture style (86.6%). They preferred integrative lectures to traditional lectures. The degree of satisfaction with E-learning and practice were much higher than with face-to-face. Most of the students identified the knowledge of interdisciplinary relationship and participating in cadaveric dissections as the important effects of this lecture style. CONCLUSION: From this study, it can be suggested that integrative lecturing in basic sciences for public health- / medicine- related courses is effective in teaching and learning. Further studies for the development of integrative contents and system are needed.

CD98 Activation Increases the Invasion of Human Breast Carcinoma MCF-7 Cells / 체질인류학회지

CD98, a disulfide-linked 125-kDa heterodimeric type II transmembrane glycoprotein, regulates the func-tions of beta1 integrin, suggesting that it may play a role in tumor cell invasion. In this study, the effects of CD98 signaling on the adhesion and invasion of tumor cells were investigated. The expression of CD98 on MCF-7 human breast carcinoma cells was confirmed by immunohistochemistry. The effects of CD98 activation on the adhesion to extracellular matrix (ECM) and invasion of MCF-7 cells were determined by adhesion assay and cell invasion assay. Dominant negative forms of focal adhesion kinase (FAK) were transiently transfected into MCF-7 cells using liposome reagents. CD98 stimulation increased the adhesion of MCF-7 cells to fibronectin, laminin and collagen IV. Activation of CD98 augmented the invasion rate of MCF-7 cells through ECM. EDTA or a function-blocking anti-beta1 integrin mAb suppressed the effect of CD98 on invasiveness. Inhibition of phosphorylation of FAK by PP2, an inhibitor of Src family kinase, reduced CD98-induced invasion of MCF-7 cells. This result was confirmed by over-expression of dominant negative forms of FAK. In addition, cytochalasin D or phalloidin inhibited CD98-mediated induction of tumor cell invasion. Inhibitory effects of PP2, cytochalasin D or phalloidin on CD98-stimulated invasion of MCF-7 cells were diminished by pretreatment of cells with Mn++, which is shown to induce conformational change of beta1 intgerin. These results provide the first evidence that CD98 activation increases tumor cell invasion by activating beta1 integrin affinity, and that FAK phosphorylation and subsequent cytoskeletal reorganization may be essential for CD98-mediated regulation of cell motility.

Relationship of Angiopoietin-2 Expression to Atherosclerosis in Middle Cerebral and Coronary Arteries / 대한해부학회지

Atherosclerosis is a systemic and multifactorial disease, its incidence is raised recently. Cerebral and coronary atherosclerosis have some similar pathogenesis, but their relationship and mechanisms are still remain unclear. Intimal neovascularization in the atherosclerotic plaque was focused with respect to its pathological roles, intimal thickening and atherosclerotic progression. Ang-2, which is an angiogenesis regulating factor, provides a destabilizing signal for endothelial cells, leading to vessel regression or sprouting. However the role and distribution of Ang-2 in atherosclerotic coronary and cerebral arteries are still not well known. Thus, we analyzed 1) atherosclerotic lesion progression 2) relationship of atherosclerosis to Ang-2 expression in human middle cerebral and coronary artery. Paraffin sections from 25 human coronary (COA) and 36 middle cerebral arteries (MCA) were characterized according to AHA classification. In the same person, the score of atherosclerosis progression in COA was higher than that of MCA. In the two kinds of arteries having same atherosclerotic progression, the degree of intimal proliferation and luminal stenosis in COA was higher than that of MCA. Expression of Ang-2 was not shown in normal artery but localized in lumen-lining endothelium, macrophage in preatheroma, atheroma and complicated lesion. Ang-2 expression and infiltration of macrophages were rich in COA than MCA. Our result indicated that cerebral atherosclerosis has some different pathogenic mechanisms with coronary atherosclerosis according to difference of progression and angiogenic factor Ang-2 expression. Thus this is a fundamental study for understanding the progression of atherosclerosis in different vascular beds.

Activation of Nuclear Factor-kappaB in the Atherosclerotic Human Coronary Artery / 대한해부학회지

Paraffin sections of atherosclerotic vessels were classified into initial lesion, preatheroma and complicated severe lesion by classification method from American Heart Association. Activation of NF-kappaB was hardly detectable in the initial atherosclerotic lesion. In the preatheroma, activated NF-kappaB was enhanced in the neointimal smooth muscle cells and macrophages in the lipid core. In contrast, activated NF-kappaB increased markedly in the neointimal and medial smooth muscle cells in the severe atherosclerotic vessel wall. However, in the severe lesion, NF-kappaB activation was diminished in the macrophages of lipid core. Our findings show that NF-kappaB was activated in the smooth muscle cells with the progression of atherosclerosis in the human coronary artery.

Release of heat shock protein 70 (Hsp70) and the effects of extracellular Hsp70 on matric metalloproteinase-9 expression in human monocytic U937 cells

Heat shock protein 70 (Hsp70) release and its effects on pro-inflammatory cytokine production have been controversial. In this study, we investigated whether Hsp70 could be released from monocytes and activates matrix metalloproteinase-9 (MMP-9) gene expression. Hsp70 overexpression in human monocytic cell line U937 was found to increase PMA- induced MMP-9 expression and enhance cell motility. Hsp70 cDNA transfectants released Hsp70 protein into culture supernatants, and a part of released Hsp70 subsequently was bound to the surface of U937 cells. Addition of culture medium containing the extracelluar Hsp70 led to an increase not only in proMMP-9 secretion, but also the invasiveness of U937 cells through Matrigel or human umbilical vascular endothelial cells (HUVEC) in vitro. Immunodepletion of Hsp70 abolished its effect on MMP-9 expression. The released Hsp70 activated nuclear factor kappa B (NF-kappa B) and activating protein-1 (AP-1), which led to the activation of MMP-9 transcription. Taken together, these results suggest that extracellular Hsp70 induces the expression of MMP-9 gene through activation of NF-kappa B and AP-1.

Pathophysiological Role of Angiopoietin-2 in Human Coronary Atherosclerosis / 대한해부학회지

Neovascularization is well known to occur in human atherosclerotic plaques; however, its pathophysiological roles, mechanism, and stimuli still remain unclear. Angiopoietin-1 and -2 belong to another vascular-specific growth factor family and regulate angiogenesis. Angiopoietin-2 (Ang-2) provides a destabilizing signal for endothelial cells, leading to vessel regression or sprouting depending on the presence of other angiogenic factor. But role and distribution of Ang-2 in atherosclerosis are not well known. Thus, we studied 1) the distribution and amount of Ang-2 2) the relationship between Ang-2 expression and vascular morphometrical change 3) the relationship between Ang-2 expression and neovascularization in atherosclerotic lesions. Paraffin sections from 36 human coronary arterial segments were characterized as normal, preatheroma, atheroma, fibroatheroma and complicated lesion according to American heart association classification. Expression of Ang-2 and related factors were examined using immunohistochemistry and western blotting with antibodies against Ang-2, CD31 (endothelial cells), alpha-actin (vascular smooth muscle cells), CD36 (monocyte & macrophage), Tie-2 and VEGF. Expression of Ang-2 was not shown in normal arterial segment. Ang-2 were localized in lumen-lining endothelium, macrophage, some SMCs of atheromatous plaque in advanced lesion. Amount of Ang-2 was increased according to progression of atherosclerosis. Intraplaque microvessels had Ang-2 and VEGF positive endothelial cells and number of those in plaque increased according to progression of disease. Intimal neovascularization is correlated with intimal thickening in atherosclerotic lesion (R2 = 0.7424). Therefore, they suggest that Ang-2 has an important role in the progression of human coronary atherosclerosis, as well as in neovascularization. This study implicates Ang-2 as an important potential therapeutic target in vascular disease

Ox-LDL suppresses PMA-induced MMP-9 expression and activity through CD36-mediated activation of PPAR-gamma

During chronic inflammatory response, mono- cytes/macrophages produce 92-kDa matrix metalloproteinase-9 (MMP-9), which may contribute to their extravasation, migration and tissue remodeling. Activation of peroxisome proliferator- activated factor receptor-gamma (PPAR-gamma) has been shown to inhibit MMP-9 activity. To evaluate whether ox-LDL, a PPAR-gamma activator, inhibits PMA-induced MMP-9 expression and activity, and if so, whether CD36 and PPAR-gamma are involved in this process, we investigated the effect of ox-LDL on MMP-9 expression and activity in PMA-activated human monocytic cell line U937. PMA-induced MMP-9 expression and activity were suppressed by the treatment with ox-LDL (50 micrigram/ml) or PPAR-gamma activators such as troglitazone (5 micrometer), ciglitazone (5 micrometer), and 15d- PGJ2 (1 micrometer) for 24 h. This ox-LDL or PPAR-gamma activator-mediated inhibition of micrometer P-9 activity was diminished by the pre-treatment of cells with a blocking antibody to CD36, or PGF2a (0.3 micrometer), which is a PPAR-gamma inhibitor, as well as overexpression of a dominant-negative form of CD36. Taken together, these results suggest that ox-LDL suppresses PMA-induced MMP-9 expression and activity through CD36-mediated activation of PPAR-gamma.

Role of Cardiac Transcription Factor Nkx2.5 on Cardiomyoplasty Model in vitro / 대한해부학회지

Despite therapeutic advance, the prevalence of ischemic heart disease continues to increase. Recently, cell transplantation of stem cell has been proposed as a strategy for cardiac repair following myocardial damage. However, low differentiation efficiency into cardiomyocyte and poor cell viability associated with transplantation have limited the reparative capacity of these cell. In this study, we engineered P19 embryonal carcinoma cells using plasmid vector to overexpress the transcription factor MEF2c, Nkx2.5 involved in cardiomyogenesis. We investigated 1) formation of intercellular junction of P19 in mono-culture and co-culture with cardiomyocyte for functional and structural synchronous contraction after transplantation, 2) differentiation into cardiomyocyte, 3) resistance to hypoxic condition. An P19 embryonal carcinoma cell line expressing GFP, MEF2c, Nkx2.5 was generated by gene transfection and clonal selection. Nkx2.5 overexpression induced connexin43 expression level decrease. Electron microscopy revealed myofibril organization and immunostaining with cTnT showed positive staining in P19-Nkx2.5, consistent with early stage cardiomyocyte. Connexin43 and N-cadherin was expressed between P19-MEF2c and cardiomyocyte, P19- Nkx2.5 and cardiomyocyte in co-culture. And beating rate of cardiomyocyte co-cultured with P19-Nkx2.5 increased much more than other group, even if P19-Nkx2.5 did not have synchronous contraction with cardiomyocyte. Additionally, P19-Nkx2.5 had a resistance against hypoxia. These result suggest that overexpression of Nkx2.5 induced differentiation of P19 into cardiomyocyte and would be electro-mechanical coupling with cardiomyocyte after transplantation. Futhermore, Nkx2.5 overexpression had protection potential to hypoxic injury. Therefore, P19 cell overexpressed Nkx2.5 would be promising cell source for further study of new therapy of myocardial disease and building up in vitro model.

Formation of Intercellular Junction between Cardiomyocyte and H9c2 Cell Line in Co-Culture / 체질인류학회지

Recently, new treatments for human heart disease such as ischemia, infarction, cardiomyopathy, coronary heart disease have been developed. transplantation various kinds of cells from skeletal muscle, endothelium, mesenchyme, hemopoietic tissue to injured area after infarction were challenged. It's so called 'Cell Transplantation'. This therapeutic strategy already adopted and got a good result in clinical trial. But several limitations are still remained, including ethics, donor cell numbers, side effects, therapeutic efficiency. In this research, we investigated the formation of intercellular junction and synchronous contraction between cardiomyocyte and H9c2 cell line in co-culture to establish experimental model in vitro for cell transplantation. For this purpose, two kinds of cells, primary cultured cardiomyocyte and H9c2 (cardiomyoblast cell line) were used. Cultured cardiomyocytes had repetitive contraction-relaxation pattern along longitudinal axis both in single and coculture. But their contractions were slower, less regular, less strong in co-culture than in cardiomyocyte culture only. H9c2 cells did not contracted actively themselves, but moved toward cardiomyocyte passively coincided with contraction. In contact region between two kinds of cells, there was no signal after immunocytochemical staining labeled with connexin43 (gap junction), desmoplakin (desmosome), N-cadherin (adherent junction) even though they had membrane contact. Moreover, F-actin and striation were less developed. These results suggested that co-culture system interfere with remodelling of contractile apparatus, intercellular junction formation as well as contraction-relaxation. Furthermore cardiomyocyte could not induce H9c2 cells differentiation into cardiomyocyte. Therefore, much more research would be essential for clinical application of cell transplantation and this study would be the basic source for further study of new therapy of myocardial disease and building up in vitro model.

Metastasis-suppressor KAI1/CD82 induces homotypic aggregation of human prostate cancer cells through Src-dependent pathway

To investigate the functional role of KAI1/CD82, a metastasis suppressor for human prostate cancer, in the regulation of homotypic cell adhesion, we transfected KAI1 cDNA into DU 145 human prostate cancer cells and established stable transfectant clones with high KAI1/CD82 expression. The KAI1 transfectant cells exhibited significantly increased homotypic cell aggregation in comparison with the control transfectant cells. This aggregation of the KAI1 transfectants was further enhanced upon exposure to anti-CD82 antibody, suggesting that KAI1/CD82 may be involved in the intracellular signaling for the cell adhesion. Among several signal pathway inhibitors tested, PP1, an inhibitor of Src family kinases, significantly suppressed homotypic aggregation of the KAI1 transfectant cells. Ligation of KAI1/CD82 with anti-CD82 antibody increased endogenous Src kinase activity of the KAI1 transfectant cells. When different types of src expression constructs were retransfected into the KAI1-transfected DU 145 cells, kinase-negative mutant src transfectant cells exhibited much lower homotypic aggregation than the mock cells transfected with an empty vector. Moreover, homotypic aggregation of the mutant src transfectant cells was not enhanced by KAI1/CD82 ligation with anti- CD82 antibody. These results suggest that Src mediates the intracellular signaling pathway of KAI1/CD82 for the induction of homotypic adhesion of human prostate cancer cells.

Functional involvement of src and focal adhesion kinase in a CD99 splice variant-induced motility of human breast cancer cells

Earlier report showed that expression of a splice variant of CD99 transmembrane protein increases invasive ability of human breast cancer cells. Cell motility was also significantly enhanced by the CD99 splice variant expression. In an effort to identify the cellular components that mediate a signal transduction pathway triggered by the CD99 splice variant, known signal path inhibitors were examined for their effects on the motility of the CD99 splice variant-transfected MDA-MB-231 breast cancer cells. Phenylarsine oxide, an inhibitor of phosphatase specific for focal adhesion kinase, and PP1, an inhibitor of src kinase family, significantly suppressed motility of the cells. Among different types of src transfectant clones generated, kinase-negative mutant src transfectant cells were 80% less motile than the mock cells transfected with an empty-vector, while v-src and c-src transfectants exhibited cell motility levels at or slightly above the mock transfectant. These results suggest that src and focal adhesion kinase mediate the intracellular signaling pathway of a CD99 splice variant for the induction of motility of human breast cancer cells.

Immunoreactivity of CD99 in Stomach Cancer

CD99 is characteristically expressed in Ewing's sarcoma/primitive neuroectodermal tumor. Recently its immunoreactivity has also been reported in other tumors. However, the significance of CD99 isoforms expressed in these tumors has not been elucidated. In this study, we evaluated the expression of CD99 isoforms and its relationship with histopathologic parameters in gastric adenocarcinomas. Paraffin sections of 46 gastric adenocarcinomas were stained with an anti-CD99 monoclonal antibody, YG32. Twelve (26.1%) cases of 46 gastric adenocarcinomas showed immunoreactivity to YG32. The CD99 expression was also seen both in non-neoplastic foveolar epithelial cells and infiltrating lymphocytes. In addition, Western blot and RT-PCR analyses revealed that the type I is the predominant isoform of CD99 in non-neoplastic and neoplastic gastric tissues. The CD99 expression was usually seen in the intestinal type adenocarcinoma, while rarely in the diffuse type. The CD99 immunoreactivity decreased in MMP-2-overexpressing adenocarcinomas (p=0.028). Our results suggest that the type I is the major isoform of CD99 expressed in non-neoplastic gastric mucosa and gastric adenocarcinomas and its downregulation in gastric adenocarcinoma may be associated with cellular dedifferentiation and/or MMP-2 overexpression.

Regulation of homotypic aggregation of myeloma-derived cell line IM-9 by CD82 / 대한해부학회지

Although reduced expression of CD82 transmembrane protein facilitates metastasis of cancer cells, little is known about its biological function. Here we have investigated the role of CD82 in B cell lymphocyte adhesion. When IM-9 cells were engaged with anti-CD82 monoclonal antibody, they formed homotypic aggregates in a short time. This adhesion was inhibited by anti-CD11a monoclonal antibody that has been known to block LFA-1-mediated cell adhesion. The cell surface expression of LFA-1 has not been changed by CD82 engagement. Homotypic aggregation was decreased in the cells in which the level of CD82 expression was low, and it was not recovered by anti-CD99 monoclonal antibody or PMA that has been known to stimulate cell adhesion. In addition, it was recovered by Mg++ treatment that induces conformational change of LFA-1 moleucles, but not by Ca++ treatment that leads to clustering of LFA-1 on the cell surface. CD82-induced cell aggregation was dramatically abrogated by addition of the phos-phatidylinositol 3-kinase (PI3-K) inhibitor LY294002 or p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. Taken together, these results suggest that CD82 molecule may fascilitate adhesion of lymphocytes by inducing conformational change of LFA-1 to pro-adhesive structure through PI3-K or p38 MAPK signal pathway.

The Effect of Green Tea Catechin on Epithelial Cancer Cell Lines / 대한해부학회지

Catechin is main component of polyphenol extracts from green tea, it is associated with prevention of hypertension and atherosclerosis, anti-diabetic effect, antioxidant, antitumor. The purpose of this research is to investigate the effect and its mechanism of green tea catechin on epithelial cancer cell lines in various concentrations and durations. For this study, epithelial cancer cell lines, A549 (lung cancer), EATC (Ehrlich-Lettre ascites tumor cell) were used. Inverted, light, confocal and electron microscopes were applied to find morphological changes. MTT assay, flowcytometric analysis, gel electrophoresis were used to compare severity of cellular damages to control after exposure to 1, 10, 100 and 500 microgram/ml catechin for 48 hours. In the A549 cells, after 1 microgram/ml and 10 microgram/ml catechin treatments, there was no notable changes. However, exposure to 100 microgram/ml catechin induced increase of cytoplasmic granules, destruction of lamellar body, inhibition of cell cycle, especially G0/G1. In the early phase of 500 microgram/ml catechin administration, decrease of cell population, severe destruction of lamellar bodies and mitochondria, derangement of cell cycle were shown. In the EATC, such as those effects occurred after exposure to lower concentration of catechin than in that of A549 cells. After exposure of 10 microgram/ml catechin, rounded-up cells and necrotic cells were found. Whereas, most of cells were under apoptotic changes-cytoplasmic condensation, nuclear fragmentation, cellular shrinkage, ladder pattern in the electrophoresis, when administrated 100 microgram/ml catechin. These results suggested that exposure of catechin induced severe cellular damage and growth inhibition in dose- and time-dependent manner. And we confirmed that these effects of catechin were involved with apoptosis, necrosis and cell cycle arrest and were quite different according to cancer type. Therefore, much more research would be demanded before clinical application of catechin to human cancer therapy and this study would be the basic source for further study of green tea.

The Delayed Phase of Protection in Heat-Induced Preconditioning: Role of the Heat Shock Protein associated with cytoskeleton

BACKGROUND AND OBJECTIVES: We investigated the ability of a brief heat shock on day one to provide delayed protection against lethal heat stress on day two in a rat-derived H9c2 cardiomyoblast cell line with reference to the role of heat shock protein 25/27, 70i and the p38MAPK signalling pathway. MATERIALS, METHODS AND RESULTS: Heat preconditioning(Heat P; 20min at 42+/-0.1degrees C) and adenosine(ADO) administered on day 1 protected against cell death under lethal heat challenge (75min at 42+/-0.1degrees C) on day 2 as measured by MTT test: ( % cell viability: Heat P: 79.9+/-3.23%, ADO: 71.9+/-4.10% vs. control: 52.7+/-1.65% respectively ). This protection was abolished by treatment with SB203580 or cytochalasine D prior to the protective stimulus on day 1( SB203580: 64.1+/-4.37%, cytochalasine D: 73.1+/-4.33% vs. Heat P ). Western blotting analysis indicated a significant accumulation of hsp70i in Heat P and SB203580-treated Heat P cells compared to control and adenosine-, SB203580-treated cells. Phosphorylation of hsp25 was significantly increased in Heat P cells compared to control cells. We also observed fragmentation of F-actin and formation of F-actin aggregates in cells exposed to lethal heat challenge. In contrast, the delayed cytoprotection preserved the F-actin bundles under lethal heat challenge. Hsp27-overexpressed, stable clones were more resistant to lethal heat shock when compared to control cells transfected with the vector alone. CONCLUSION: These data suggest an important role for p38MAPK/hsp25/27 pathway as a potential distal effector of heat-induced delayed protection.

Role of adenosine in the cardioprotective effect of ischemic preconditioning in the isolated rabbit hearts / 대한해부학회지

This study was designed to provide a evidence that adenosine-mediated activation of protein kinase C and K(ATP) channel was a important step on the cardioprotection mechanism of ischemic preconditioning (IP). Isolated Langendorff-perfused New Zealand White rabbit hearts were subjected to 45 min of global ischemia (I) and 120 min reperfusion (R) with or without IP. IP was induced by a single dose of 5 min I and 10 min R. Part of the IP hearts was treated with non-specific adenosine receptor blocker 8-sulfophenyltheophylline (SPT; 100 micromol) and K(ATP) channel blocker glibenclamide (10 micromol) 5min before IP, respectively. To determine the effect of IP, we measured the left ventricular function, infarct size, adenosine concentration in the coronary flow and total protein kinase C activity. PKC activity was determined by (32)P-gamma-ATP incorporation into PKC specific peptide. IP enhanced improvement of functional recovery and caused a decrease in the infarct size from 19.9+/-0.05% in the ischemic-control group to 5.5+/-1.39% in the IP group (p<0.05). In the SPT- and glibenclamid-treated hearts, however, these anti-ischemic effect was disappeared. Adenosine release from the cardiac tissue was abruptly increased to 10~20 folds baseline just after IP. Cytosolic PKC activity decreased significantly in the IP hearts, while in the membrane fraction, activity was increased (45 min I, p<0.05; 120 min R, p<0.01). In the SPT-treated hearts, IP did not make those activity changes of PKC. These data suggest that adenosine induced the anti-ischemic effect via PKC activation. And it also show that K(ATP) channel may work on the protection as a final effector.