Carcinosarcoma (True Malignant Mixed Tumor) of the Parotid Gland: A Report of a Case with Small Cell Carcinoma as the Carcinoma Component

True malignant mixed tumor (carcinosarcoma) of the salivary gland is an extremely rare tumor. By definition, it is a heterologous neoplasm that's composed of both malignant epithelial and mesenchymal components. We report here on a case of an 83 year old female patient with a parotid gland mass. Histologic examination showed a biphasic pattern of growth with both a poorly differentiated epithelial component and a sarcomatous spindle cell background. The immunohistochemical and ultrastructural findings support the diagnosis of a small cell neuroendocrine epithelial tumor and an undifferentiated malignant mesenchymal features. The histologic and ultrastructural features along with the immunohistochemical findings are presented. We also review the literature and we discuss the different opinions on the exact histogenesis of the true malignant mixed tumor of the salivary gland. To the best of our knowledge, this histological pattern has not been previously reported in the English medical literature.

Screening of Low Molecular Metabolite, FS390 as an Inhibitor of Neurotransmitter Release from PC12 Cells / 대한해부학회지

We established an in vitro experimental system using the following procedure. We first introduced tritium-labeled norepinephrine ([3H]-NE) into PC12 cells. The [3H]-NE incorporated-PC12 cells were stimulated by a high concentration (60 mM) of K+ buffer during 12 minutes. Then, we collected 100 microliter supernatant and counted the amount of [3H]-NE release from PC12 cells with a scintillation counter. After screening fungal, Streptomyces spp. or bacterial product using this experimental sytem, we obtained FS390 from Streptomyces spp. which inhibited [3H]-NE release from PC12 cells. FS390 also inhibits the release of ATP as a neurotransmitter of PC12 cells and rat cortical neurons. The inhibitory effect was seen even when the PC12 cells were treated with low K+ buffer containing ionomycin (1 micrometer) as an ionopore. This result suggests that the inhibitory action of FS390 on neurotransmitter release appeared after the influx of Ca2+.

Rebamipide Protects TNBS Induced Colonic Damage Through Down-regulation of NF-kappaB Activation and Induction of Heme Oxygenase -1 Expression / 대한해부학회지

Crohn 's disease is characterized by a chronic relapsing inflammation of the bowel in which pro-inflammatory cytokines play an important role. Rebamipide is an anti-gastric ulcer drug with anti-inflammatory properties in vivo and in vitro. The effects of rebamipide on Crohn 's disease have not been carefully evaluated. This study investigated the potential of rebamipide to protect Crohn 's disease using a murine model of colitis induced by trinitrobenzene sulfonic acid (TNBS). Rebamipide dramatically improved histopathological symptom involving myeloperoxidase (MPO)activation and increase of microscopic damage score in TNBS induced colitis. Rebamipide suppressed IL-8 secretion, ICAM-1 induction and nuclear factor-kappaB (NF-kappaB) activation by TNF-alpha and induced heme oxygenase-1(HO-1)in HT-29 cells. HO-1 inducer cobalt protoporphyrin IX (CoPPIX)suppressed NF-kappaB activation by TNF-alpha in HT-29 cells like rebamipide, and mimicked the protective effects of rebamipide on TNBS induced colitis. This suggests that rebamipide exerts anti-inflammatory effects by down-regulating NF-kappaB activity via inducting HO-1 expression. In conclusion, this study suggests that rebamipide represents a potential therapeutic agent and HO-1 is an important therapeutic target for the treatment of Crohn's disease.

Rebamipide Protects Colonic Damage Induced by Trinitrobenzene Sulfonic Acid (TNBS) via Down-Regulation of TNF-alpha IL-1beta and ICAM-1 / 대한해부학회지

During inflammation of the colon, cells of the gut mucosa produce or express numerous inflammatory mediators, such as tumor necrosis factor-alpha (TNF-alpha), interleukin-1beta (IL-1 beta), and intercellular adhesion molecule 1 (ICAM-1). These mediators have been implicated as contributory factors to the inflammatory process, which results in colitis during inflammatory bowel disease (IBD). Rebamipide is an anti-gastric ulcer drug with anti-inflammatory properties in vivo and in vitro. The effects of Rebamipide on IBD have not been largely evaluated. Therefore, this study investigated the potential of Rebamipide to regulate the production of inflammatory mediators such as TNF-alpha, IL-1beta, and ICAM-1. Mice with trinitrobenzene sulfonic acid (TNBS)-induced colitis (IBD animal model), were treated intrarectally with 2 mM Rebamipide. Body weight, macro- and micro-histological scores, and activity were evaluated. As an index of tissue edema, the thickness of the colonic wall was measured between the serosal surface and the luminal surface of the mucosa. TNF-alpha, IL-1 beta, and ICAM-1 were detected by immunohistochemical staining. Rebamipide treatment of mice exhibiting TNBS-induced colitis dramatically improved the clinical and histopathological findings of inflammation. In addition, Rebamipide suppressed TNF-alpha, IL-1 beta, and ICAM-1 expression in TNBS-treated animals. Taken together, these findings suggest that Rebamipide is a potential therapeutic agent for treating patients with IBD.

Effects of Sulphasalazine and Glucocorticoid on the Regulation of CCL20 Gene Expression in the Peripheral Blood Cells of Korean Patients with Ulcerative Colitis / 대한해부학회지

Discovery of Nod2 has brought to light the significance of mononuclear cells as well as epithelial cells in inflammatory bowel disease (IBD) pathogenesis. Similarly, CCL20 is expressed in both mononuclear cells and epithelial cells and is likely to link innate and acquired immunity. We therefore asked whether CCL20 expression is altered in the peripheral blood mononuclear cells (PBMCs) from patients with ulcerative colitis (UC), a major type of IBD in Korea, and is correlated with the disease activity. The expression levels of CCL20 mRNA were significantly high in the PBMCs from the patients with UC. CCL20 protein expression was also up-regulated in the mucosal epithelium in UC but not in normal controls. Interestingly, however, disease activity index (DAI) revealed that untreated UC groups express higher expression levels of CCL20 mRNA than treated UC groups, implying that CCL20 may be a potential target for the anti-inflammatory treatments. In an agreement with this, three months follow up study revealed that the UC patients who were treated with 5-amino salicylic acid (5-ASA) and glucocorticoid showed dramatic decrease in their CCL20 mRNA levels as compared to untreated ones. Moreover, TNF-alpha-or IL-1beta-induced CCL20 secretion in human epithelial HT-29 cells was significantly diminished by the treatment with 5-ASA and/or dexamethasone, suggesting that CCL20 may be one of the central targets of the anti-inflammatory drugs. Collectively, these results suggest that CCL20 expression in UC may be associated with altered immune and inflammatory responses in the blood as well as the intestinal mucosa and further implied a potential for CCL20 as an important diagnostic marker for UC.

Heme Oxygenase-1 is Involved in the Down-regulation of Nuclear Transcription Factor kappa B Activation in the Colonic Epithelium During Inflammation / 대한해부학회지

Heme oxygenase-1 (HO-1) is a stress-inducible enzyme with anti-inflammatory activity, but the mechanisms underlying this activity are incompletely understood. Nuclear transcription factor kappa B (NF-kappa B) activation is an important factor in the pathogenesis of inflammatory bowel disease (IBD). We investigated the suppressive effects of HO-1 on the activation of NF-kappa B by pro-inflammatory cytokines in cultured colonic epithelial cells and by trinitrobenzene sulfonic acid (TNBS) in the colon of mice. The expression level of HO-1 in the colonic epithelium of a patient with inflammatory bowel disease and pseudo-membranous colitis was lower than that in a healthy control subject. In cultured human colonic epithelial HT-29 cells, pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha ) and IL-1 beta down-regulate HO-1 expression. The HO-1 inducer, cobalt protoporphyrin IX (CoPPIX), dramatically down-regulated NF-kappa B activation in HT-29 cells by TNF-alpha. In addition, bilirubin-a product of heme catabolism by HO-1-and the carbon monoxide donor tricarbonyldichlororuthenium (II) dimer also suppressed NF-kappa B activation by TNF-alpha. However, iron, another heme metabolite, did not suppress NF-kappa B activation by TNF-alpha. Furthermore, CoPPIX diminished the macroscopic and histopathological symptoms of TNBS-induced colitis and down-regulated NF-kappa B activation in mice. In conclusion, this study suggests that HO-1 plays an important role in the down-regulation of NF-kappa B activation, which is a key factor in the pathogenesis of IBD and is thus an excellent therapeutic target for the treatment of IBD.

Gliotoxin Protects Against TNBS-induced Colitis Via Down-regulation of NF B Activation / 대한해부학회지

During inflammation of the colon, cells of the gut mucosa express numerous inflammatory mediators including interleukin-8 (IL-8), tumor necrosis factor-alpha (TNF-alpha), and interleukin-1beta(IL-1beta). These cytokines have been implicated as contributing factors in the inflammatory process, which may result in colitis during inflammatory bowel disease (IBD). Gliotoxin is a fungal metabolite of an epipolythiodioxopiperazine analogue with immunosup-pressive properties in vivo and in vitro, but the effects of gliotoxin on IBD have not been largely evaluated. Therefore, this study evaluated the potential of gliotoxin to protect against TNBS-induced colitis. One microgram of gliotoxin in 100microliter of vehicle was intra-rectally administered into mice exhibiting trinitrobenzene sulfonic acid (TNBS)-induced colitis. IL-8 secretion was measured using an enzyme-linked immu-nosorbent assay (ELISA), myeloperoxidase (MPO) activity was evaluated spectrophotometically, and IkappaB degradation was analyzed on Western blots. Gliotoxin treatment of mice bearing TNBS-induced colitis improved macro-and micro-pathological findings and dramatically decreased MPO activity, a marker of leukocyte infiltration. Furthermore, gliotoxin decreased IkappaB degradation and IL-8 induction caused by TNF-alpha or IL-1beta in HT-29 cells. These findings suggest that gliotoxin partially protects against TNBS-induced colitis through the sup-pression of IL-8 induction and IkappaB degradation by inflammatory mediators such as TNF-alpha or IL-1beta.

Protective Effect of PKC and Nitric Oxide Affecting Taxol-Induced Cytotoxicity in C6-Gial Cells / 대한해부학회지

Paclitaxel (Taxol) is known as effective drug for inhibition of cell cycle encouraging in human cancer cells. This drug named an antimicrotubule agent which simulate the mitotic arrest towards an apoptosis. The influence of phorbol 12 myristate 13 acetate (PMA) activated protein kinase C (PKC) and nitric oxide (NO) on taxol-induced apoptosis, is poorly understood. To investigate the effects of PMA and NO on the signal transduction in taxol-induced apoptosis in C6-glial cells, the viability and caspase-3 activity of C6-glial cells were analyzed. Pretreatement with PKC activatior (PMA) protected taxol-induced cell death in C6-glial cells, by inhibited caspases-3 activity. On the other hand, the taxol-induced apoptosis was highly enhanced by sodium nitroprusside (SNP) and lipopolysaccharide (LPS), as NO activator. These results suggest that PMA strongly blocks the apoptotic effect of taxol, while nitric oxide has no protective effects in the process of toxol-induced apoptosis in C6-glial cells.

Protective Effect of PKC Affecting Gliotoxin-induced Cytotoxicity in Rat Smooth Muscle Cells / 대한해부학회지

Aspergillus funigatus and other pathogenic fungi synthesize a toxic epidithi-odiopiperzine (ETP) metabolite, namely gliotoxin. Gliotoxin commonly react with sulfhydryl groups, and then, forms hydrogen peroxide. These fungal toxins induce apoptotic cell death in various cells. Apoptosis induced by gliotoxin need calcium. Effect of calcium preconditioning was not reported in gliotoxin-induced apoptosis. To examine the effect of protein kinase C (PKC) and calcium which was regulate caspase-3, PKC and calcium preconditioning before gliotoxin treatment, apoptotic agents such as bcl-2 family, caspase-3 and DNA fragmentation in A7r5 cell line from rat smooth muscle cell were studied. These results showed that gliotoxin induces the expression of bad of bcl-2 family, caspase-3 activation and DNA fragmentation in A7r5 cells. Gliotoxin treatment followed by calcium and PKC preconditioning suppress the Bad of bcl-2 family, and inhibited caspase-3 activation, respectively. These results suggest that PKC and calcium preconditioning protect the gliotoxin-induced apoptosis, through the protection of pro-apoptotic bcl-2 family in A7r5 cells.

The Effect of Protein Kinase C Pretreatment on Gliotoxin Induced Apoptosis in H9c2 Cells / 체질인류학회지

Aspergillus funigatus and other pathogenic fungi synthesize a toxic epidithi- odiopiperzine (ETP) metabolite called gliotoxin. Gliotoxin is an epidithiodiopiperzine compound which can both react with sulfhydryl groups and form hydrogen peroxide. The fungal toxin gliotoxin induces apoptotic cell death in a variety of cells. Apoptosis induced by gliotoxin need calcium but effect of calcium preconditioning is unknown by gliotoxin. We studied the effect of protein kinase C and calcium preconditioning on gliotoxin-induced apoptosis in H9c2 cell. PKC and calcium preconditiong inhibited DNA fragmentation by gliotoxin. From this above results suggest that gliotoxin induce apoptosis via caspase-3 activation, because caspase-3 inhibitor (DEVD-CHO) didn't induce apoptosis in gliotoxin treated H9c2 clls. Calcium and PKC preconditioning inhibit caspase-3 activation by gliotoxin. These data means that PKC preconditioning is related with caspase-3 regulate in gliotoxin-induced apoptosis.

Effects of Seongpungtang on the Nitric oxide Production of C(6) glial cell and Microglia / 대한해부학회지

Nitric oxide (NO) can be either neuroprotective or neurotoxic, depending on the cell type from which it is released and the length and severity of the ischemic insult. In the present study, we investigated the neuroprotective effect of Seongpungtang, a Oriental traditional medicine, on ischemic brain insult by C(6) glial cells and microglia produced NO. O production was induced by lipopolysaccharide (LPS) only or LPS combined with phorbol-12-myristate-13-acetate (PMA) in C(6) glial cell and microglia, and we observed the suppressive effect of Seongpungtang on NO production increased by LPS only or LPS combined with PMA. The cells treated with the water extracts of Seongpungtang at 2 mg/ml does not change the viability. And the water extracts of Seongpungtang significantly suppress the NO production induced by LPS or LPS combined PMA in C(6) glial cells and microglia. To validate the neuroprotective effect of Seongpungtang by suppression of NO production, the microglial cells were treated with NF-kB inhibitor pyrrolidine dithiocarbamate (PDTC), and it is completely decreased the NO production induced by LPS combined with PMA. Moreover, the water extracts of Seongpungtang suppress morphological degeneration by LPS combined with PMA in C(6) glial cell and microglia. These results suggest that the protective effects of the water extracts of Seongpungtang against ischemic brain damages may be mediated by regulation of iNOS during ischemic condition.

Zinc-Induced Cell Death in H9c2 Cardiomyoblast cells / 대한해부학회지

Adriamycin (ADR) is a potent anticancer drug that causes often severe cardiomyopathy. Previous reports have demonstrated that zinc accumulation is shown in rat myocardial cells following ADR treatment. However, the mechanism and role of zinc accumulation in ADR-induced cardiomyopathy are not yet elucidated. Zinc may be one of the key executors in ADR-induced cardiomyopathy. To test this hypothesis, we examined the cytotoxic effects of zinc on various cell lines including H9c2 cardiomyoblast cells, HL-60, U937, and C(6)-glial cells. Zinc induced significant the death of H9c2 cells at 0.125 mM in a dose-dependent manner. However, zinc did not induce any cytotoxic effect on both promyelocytic leukemic HL-60 cells and monoblastoid U937 cells. The nuclear morphology of Zn(2+)-treated H9c2 cells displayed apparent chromatin condensation, but no formation of chromatin fragmentation. In addition, phosphatidylserine (PS) externalization was observed by annexin-V staining. Zinc markedly decreased the intracellular GSH level in a time-dependent manner. Exposure to 0.2 mM ZnCl(2) for 6 hr decreased the intracellular GSH content to 13% of control value. Zinc-induced death of H9c2 cells and the intracellular GSH depletion were completely prevented by the addition of exogenous GSH and NAC. These result suggests that intracellular GSH depletion is directly involved in zinc-induced cardiomyopathy.

Protective Effect of PKC Affecting Taxol-induced Cytotoxicity in MCF-7 Cells / 대한해부학회지

Paclitaxel (taxol) is known as effective drug inhibition of cell cycle encouraging activity in human ovarian and metastatic breast cancers and malignant melanoma. It is an antimicrotubule agent that is believed to mediate its antineoplastic effects by inducing mitotic arrest followed by apoptosis. The relation between phorbol 12 myristate 13 acetate (PMA), protein kinase C (PKC) activator, and taxol-induced apoptosis is not well understood until now. This study was performed to investigate the effects of PMA on the signal transduction pathways of taxol-induced apoptosis in MCF-7 human breast carcinoma cells. Taxol-induced apoptosis is attenuated by curcumine, JNK inhibitor, and pyrrolidine dithiocarbamate (PDTC), inhibitor of NFkB. Pretreatment with PKC activator (PMA) or protein kinase A (PKA) activators (forskolin and dibutyryl cAMP) inhibited taxol-induced apoptosis in MCF-7 cells. In addition, thapsigargin, a specific inhibitor of endoplasmic reticulum(ER) Ca(2+)-ATPase and CaCl2, also blocked the activation of caspases by taxol. From these results suggest that taxol-induced apoptosis may be mediated via JNK or NFkB pathway and PKC activation.

Protective Effect of Nitric Oxide Against Lipopolysaccharide-induced Cytotoxicity in C6-glial Cell / 대한해부학회지

Nitric oxide (NO) is mainly involved in brain ischemic damage to elucidate the protective mechanism of NO pretreatment on ischemic-induced cytotoxicity. This study was investigated whether NO pretreatment inhibits the increase of iNOS expression by lipopolysaccharide (LPS) combined phorbol 12-myristate 13-acetate (PMA) via regulating NF-kB activation in C6 glial cells. C6 glial cells with LPS and PMA for 72 hours markedly induced NO, but sodium nitroprusside (SNP) (100 nM) pretreatment before exposure of LPS and PMA significantly supressed NO production, iNOS expression and NF-kB activation by LPS and PMA. In addition, LPS and PMA treatment for 72 hours induced severely cell death and LDH release from cell into media in C6 glial cells. However SNP pretreatment before treatment of LPS and PMA significantly protected LPS and PMA induced cytotoxicity. Treatment with LPS and PMA induced caspase 3 activation follewed by chromosomal condensation, and fragmentation of nuclei in C6 glial cells. SNP pretreatment before exposure to LPS and PMA supressed caspase 3 activation and inhibited chromosomal condensation and fragmentation of nuclei. From these above results, it is suggest that the protective effects of SNP pretreatment against LPS and PMA induced cytotoxicity may be mediated by inhibiting the expression of iNOS via regulating NF-kB activation.

The Role of Calcium Affecting Signal Pathway Related to Nitric Oxide-induced Cytotoxicity in H9c2 Cardiac Myoblast / 대한해부학회지

Nitric oxide (NO) elevates intracellular calcium. But the actions of calcium in NO-induced cell death are not well understood. This study was carried out to investigate the signal transduction pathways of calcium and NO-induced cytotoxicity in H9c2 cardiac myoblasts by using NO donor compounds such as sodium nitroprusside (SNP) and S-nitroso-N-acetylpenicillamine (SNAP). Pretreatment of intracellular calcium chelating agent (BAPTA/AM) or L-type calcium channel blockers (nicardipine, nifedipine, diltiazem and veraparmil) or T-type calcium channel blocker (flunarizine) blocked SNP-induced cytotoxicity respectively only in a three hours. However, thapsigargin (TG), which inhibits endoplasmic reticulum dependent Ca(2+)-ATPase and thereby increases cytosolic Ca(2+), augmented SNP-induced cytotoxicity. The protective effect of BAPTA/AM was inhibited by treatment of protein synthesis inhibitor, cyclohexamide. In addition, pyrrolidine dithiocarbamate (PDTC), NF-kB inhibitor, attenuates the protective effect of BAPTA/AM against SNP-induced cytotoxicity. It is indicated that the protective effect of BAPTA/AM against NO-induced cytotoxicity might be due to the expression of protein related to activation of NFkB. From these results, it is concluded that SNP-induced cytotoxicity is mediated by calcium in a 3 hours via down regulation of protein expression rleated to activation of NFkB.

Prenatal detection of de novo inversion of chromosome 9 with duplicated heterochromatic region and postnatal follow-up

We report the first de novo case of a heterochromatic duplication on the long arm of the chromosome 9, which then was pericentrically inverted at p11q13. This condition was detected prenatally and carry to term. We then performed the follow up for over 1 year. So far, there seems to be no phenotypical abnormalities.

The Role of Sek1 in Protecting NO-induced Apoptosis in H9c2 cells by Inhibiting Caspase 3 Activation / 대한해부학회지

The stress activated protein kinase, or Jun N-terminal kinase (SAPKs/JNKs), is activated in response to a variety of cellular stresses such as changes in osmolarity and metabolism, DNA damage, heat shock, ischemia, and inflammatory cytokines. Sek1 (JNKK/MKK4) is a direct activator of SAPKs/JNKs in response to environmental stresses or mitogenic factors. Thus, this study was conducted to investigate the role of Sek1 on nitric oxide (NO) induced apoptotic signaling pathway in H9c2 cell. The viability of SNP (Sodium Nitroprusside) treated inactive Sek1 kinase transfectants [Sek1/KI H9c2] is significantly decreased and SNP induce DNA fragmentation in Sek1/KI H9c2. Interestingly, concomitantly with SNP induced injuries, caspase 3-like activity is increased but caspase 1 like activity is not changed in Sek1/KI H9c2. Whereas wild type Sek1 kinase transfectants [Sek1/WT H9c2] is less susceptible to SNP induced apoptosis. In Sek1/KI H9c2, the injuries and DNA fragmentation by SNP is protected by adding Ac-DEVD-AMC, caspase 3 inhibitor. In conclusion, these results suggest that Sek1 plays a role in protecting NO-induced apoptosis and DNA fragmentaion in H9c2 cells by inhibiting caspase 3-like activation.

Molecular Cloning and Expression of Human Placental 3beta - Hydroxysteroid Dehydrogenase / 체질인류학회지

No abstract available.

Antioxidant Effect of Allopurinol on Oxygen Radical-Induced Toxicity in Cultured Mouse Cerebral Neurons / 체질인류학회지

In order to elucidate the neurotoxic effect of oxygen radicals on cultured mouse cerebral neurons, the neurotoxicity induced by xanthine oxidase (XO) and hypoxanthine (HX), was evaluated by MTT assay. The neuroprotective effect of allopurinol against oxidant -mediated neurotoxicity was also examined in these cultures by MTT assay and neurofilament enzymeimmunoassay (EIA) with light microscopy. The results were as follows: 1. Oxygen radicals induced degenerative changs such as the decrease of cell number and the loss of neurites in cultured mouse cerebral neurons. 2. The value of midcytotoxicity value (MTT50) of oxygen radicals was estimated at a concentration of 20 mU/ml XO and 0.1 mM HX for 4 hours in these cultures. 3. Cell viability of cultured mouse cerebral neurons was significantly decreased by XO/HX in a dose -and time -dependent manners. 4. Allopurinol was very effective in blocking the neurotoxicity induced by XO/HX at a concentration of 30 microM as determined by MTT assay and neurofilament enzymeimmunoas-say. From the above results, it is suggested that oxygen radicals show neurotoxicity, and the selective antioxidant such as allopurinol are very effective in blocking oxidant -mediated neurotoxicity on cultured mouse cerebral neurons.

Effect of NMDA Receptor Antagonist (APV)on the Toxicity Induced by Oxygen Radicals in Cultured Myocardial Cells / 체질인류학회지

Toxic effect of oxygen radicals and cardioprotective effect of N -methyl -D -aspartate (NMDA) receptor antagonists against xanthine oxidase (XO) and hypoxanthine (HX)-induced cardiotoxicity were measured in order to elucidate the mechanism of cardiotoxicity on cultured mouse myocardial cells. MTT assay was performed after myocardial cells were cultured for 12 hours at various concentrations of XO/HX alone or with D -2 -amino -5 -phosphonovaleric acid (APV) or 6 - cyano -7 -nitroquinoxaline -2,3 -dione (CNQX). In this study, XO/HX was toxic in a time -and dose -dependent manners on cultured myocardial cells, and midcytotoxicity value 50 (MTT50) was at 30 mU/ml XO and 0.1 mM HX after myocardial cells were grown for 12 hours in media containing 1 ~50 mU/ml XO and 0.1 mM HX. When cultures were treated with 30 mU/ml XO and 0.1 mM HX flus 20 80 microM APV for 12 hours, cell viability was increased remarkably, while treatment with 30 mU/ml XO and 0.1 mM HX flus 10 ~50 microM CNQX did not show any protective effect against XO/HX -induced neurotoxicity. From the above results, it is suggested that oxygen radicals are toxic on cultured mouse myocardial cells by the decrease of cell viability, and NMDA receptor antagonists such as APV are very effective in the prevention of myocardial toxicity induced by oxygen radicals.