BACKGROUND: Although kidney transplantation outcomes have improved dramatically after using calcineurin inhibitors (CNIs), CNI toxicity continues to be reported and the mechanism remains uncertain. Here, we investigated the neurotoxicity of CNIs by focusing on the viability of glioma cells.METHODS: Glioma cells were treated with several concentrations of CNIs for 24 hours at 37℃ and their cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay.RESULTS: Exposure to 0, 0.25, 0.5, 2.5, 5.0, and 10.0 mM concentrations respectively showed 100%, 64.3%, 61.3%, 68.1%, 62.4%, and 68.6% cell viability for cyclosporine and 100%, 38.6%, 40.8%, 43.7%, 37.8%, and 43.0% for tacrolimus. The direct toxic effect of tacrolimus on glioma cell viability was stronger than that of cyclosporine at the same concentration.CONCLUSION: CNIs can cause neurological side effects by directly exerting cytotoxic effects on brain cells. Therefore, we should carefully monitor the neurologic symptoms and level of CNIs in kidney transplant patients.
Animals ; Brain ; Calcineurin Inhibitors ; Calcineurin ; Cell Survival ; Cyclosporine ; Glioma ; Humans ; Kidney ; Kidney Transplantation ; Neurologic Manifestations ; Rats ; Tacrolimus

BACKGROUND: Although kidney transplantation outcomes have improved dramatically after using calcineurin inhibitors (CNIs), CNI toxicity continues to be reported and the mechanism remains uncertain. Here, we investigated the neurotoxicity of CNIs by focusing on the viability of glioma cells. METHODS: Glioma cells were treated with several concentrations of CNIs for 24 hours at 37℃ and their cell viability was evaluated using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. RESULTS: Exposure to 0, 0.25, 0.5, 2.5, 5.0, and 10.0 mM concentrations respectively showed 100%, 64.3%, 61.3%, 68.1%, 62.4%, and 68.6% cell viability for cyclosporine and 100%, 38.6%, 40.8%, 43.7%, 37.8%, and 43.0% for tacrolimus. The direct toxic effect of tacrolimus on glioma cell viability was stronger than that of cyclosporine at the same concentration. CONCLUSION CNIs can cause neurological side effects by directly exerting cytotoxic effects on brain cells. Therefore, we should carefully monitor the neurologic symptoms and level of CNIs in kidney transplant patients.

PURPOSE: We tested the effect of team-based learning (TBL) on medical education through the second-year premedical students’ TBL scores in biochemistry classes over 5 years. METHODS: We analyzed the results based on test scores before and after the students’ debate. The groups of students for statistical analysis were divided as follows: group 1 comprised the top-ranked students, group 3 comprised the low-ranked students, and group 2 comprised the medium-ranked students. Therefore, group T comprised 382 students (the total number of students in group 1, 2, and 3). To calibrate the difficulty of the test, original scores were converted into standardized scores. We determined the differences of the tests using Student t-test, and the relationship between scores before, and after the TBL using linear regression tests. RESULTS: Although there was a decrease in the lowest score, group T and 3 showed a significant increase in both original and standardized scores; there was also an increase in the standardized score of group 3. There was a positive correlation between the pre- and the post-debate scores in group T, and 2. And the beta values of the pre-debate scores and “the changes between the pre- and post-debate scores” were statistically significant in both original and standardized scores. CONCLUSION: TBL is one of the educational methods for helping students improve their grades, particularly those of low-ranked students.
Biochemistry* ; Education, Medical ; Education, Premedical ; Humans ; Learning* ; Linear Models ; Schools, Medical

The matrix metalloproteinases (MMPs) play a key role in the normal physiology of connective tissue during development, morphogenesis, and wound healing. Dysregulation of their activity has been implicated in numerous diseases including encephalopathy and the process of bone loss. Thus, MMPs may play a role in the encephalopathy and post-transplantation bone disease by immunosuppressive drugs such as cyclosporine (CsA) and tacrolimus. Gelatin zymography of MMP-9 and MMP-2 was performed in the glioma cells and osteoblast after CsA or tacrolimus treatment. Glioma cells or rat osteoblast ROS17/2.8 cells were treated with CsA or tacrolimus to make final concentration from 2 to 250 µM. After incubation, gelatin zymography of MMP-9 and MMP-2 was performed. And the density for the MMP bands were measured using luminescent image analyzer system. Both MMP-9 and MMP-2 activities in the osteoblast cells were decreased depending on the concentration of CsA or tacrolimus. MMP-2 activity was increased after CsA or tacrolimus treatment in the glioma cells. However, MMP-9 activities were decreased after CsA or tacrolimus treatment in the glioma cells. These results indicate that dysregulation of MMPs in the osteoblast and in the glioma cells by immunosuppressive drugs may one of the contributing factors in post-transplantation bone disease and in the encephalopathy by tacrolimus or cyclosporine.
Animals ; Bone Diseases ; Connective Tissue ; Cyclosporine ; Gelatin ; Glioma* ; Matrix Metalloproteinases ; Morphogenesis ; Osteoblasts* ; Physiology ; Rats ; Tacrolimus ; Wound Healing

PURPOSE: Cyanate, known as one of the uremic toxins and derived spontaneously from urea, has several effects on the biologic substances including erythropoietin, antioxidant and ceruloplasmin. To find out the protective materials from the hazardous effect of cyanate in osteoblast, we added twenty amino acids, albumin globulin and hemoglobin in the culture media containing osteoblastic cells with cyanate. METHODS: Osteoblastic ROS 17/2.8 cells, exposed to various concentrations of sodium cyanate, were used to analyze for the cytotoxicity. The cyanate-induced cytotoxicity was assessed by the methylthiazolyldiphenyl-tetrazolium bromide (MTT) assay by measuring the absorbance of the reaction solution at 570 nm. Viability of the treated cells was expressed as A570 of sample/A570 of control. The degree of the carbamylation was measured using trinitrobenzenesulphonic acid. The degree of the carbamylation in amino acid was about 50% in average. RESULTS: The degree of the carbamylation in albumin was increased depending on the incubation time with cyanate and the concentration of the cyanate. The degree of the carbamylation in globulin and hemoglobin was nearly zero. Asp, Glu, Leu, Trp and Tyr among the twenty amino acids revealed the protective effect against the damage induced by cyanate. And only albumin among the three proteins revealed the protective effect. CONCLUSION: On the basis of these results, Asp, Glu, Leu, Trp, Tyr and albumin are useful tools for the protection against damages by cyanate carbamylation.
Albumins ; Amino Acids* ; Ceruloplasmin ; Culture Media ; Cyanates ; Erythropoietin ; Osteoblasts* ; Sodium ; Urea ; Viperidae

BACKGROUND/AIMS: Nonalcoholic steatohepatitis (NASH) is chronic liver disease that can potentially progress to end stage liver disease. Oxidative stress to the vulnerable fatty liver has been reported as a key mechanism in development of NASH. Several antioxidant pathways have been identified, but reports that involved quantitative analysis of each antioxidant systems are rare, and these reports have shown various results. So, we investigated antioxidant status and the degree of oxidative stress by measuring several antioxidant enzymes, the total antioxidant status (TAS), and the metabolites of superoxide in NASH patients. METHODS: Nineteen NASH patients who were confirmed by liver biopsy and fifteen controls were involved in this study. The levels of body mass index (BMI), AST, ALT, superoxide dismutase (SOD), glutathione peroxidase (GPx), catalase, TAS, hydrogen peroxide (H2O2), and malondialdehyde (MDA) were compared between both groups. The relationship between the histologic severity and the levels of each antioxidants were analyzed in the NASH group. RESULTS: The activities of SOD and catalase were lower in the NASH group. The concentrations of TAS and H2O2 were higher in NASH group. The level of GPx and MDA showed no significant differences between both groups. There were no significant relationships between the above variables and the pathological severity. CONCLUSIONS: The disturbed metabolism of superoxide due to the decreased activities of SOD and catalase seem to be important in the pathogenesis of NASH. Further investigations about the nonenzymatic secondary antioxidant mechanism are necessary because the TAS was higher for the NASH group. The lack of difference between both groups for the concentration of MDA indicates that mechanisms other than lipid peroxidation also may be important in the pathogenesis of NASH.
Adult ; Antioxidants/*metabolism ; English Abstract ; Fatty Liver/*metabolism/pathology ; Female ; Humans ; Liver/pathology ; Male ; Oxidative Stress

BACKGROUND: The present study was aimed to know the cause of impaired bactericidal activity, especially the metabolism of oxygen free radicals in neutrophils from patients with end-stage renal disease (ESRD). METHODS: We measured the amount of superox ide anion, the activity of three antioxidant enzymes, myeloperoxidase, copper ion level, zinc ion level and the amount of malondialdehyde in neutrophils from patients with ESRD before and after hemodialysis. Reverse transcription-polymerase chain reaction (RT-PCR) for superoxide dismutase (SOD) was also done. RESULTS: The malondialdehyde level, the amount of superoxide anion, catalase, and myeloperoxidase levels in the neutrophils from the patients with ESRD were higher than those from healthy controls. SOD activity, hydrogen peroxide level and zinc level were lower in ESRD patients. On the RT-PCR, the relative index, which is defined the ratio of the band densities for SOD to glyceraldehyde 3-phosphate dehydrogenase, was decreased in neutrophils from patients with ESRD. Glutathione peroxidase activity in the neutrophils from ESRD patients did not show any significant change. CONCLUSION: These results indicate that there are some alterations in metabolism of oxygen free radicals including lower levels of hydrogen peroxide which exerting a direct germicidal ability, due to decreased gene expression and mineral levels. And these alterations might be one of the major mechanisms of impaired microbicidal activity in patients with ESRD.
Catalase ; Copper ; Free Radicals ; Gene Expression ; Glutathione Peroxidase ; Glyceraldehyde 3-Phosphate ; Humans ; Hydrogen Peroxide ; Kidney Failure, Chronic* ; Malondialdehyde ; Metabolism* ; Neutrophils* ; Oxidoreductases ; Oxygen ; Peroxidase ; Reactive Oxygen Species* ; Renal Dialysis ; Superoxide Dismutase ; Superoxides ; Zinc

BACKGROUND: Cisplatin (CP), an antitumor agent widely used in the treatment of cancers, has nephrotoxicity. This side effect is closely related to oxidative stress. In the present study, we attempted to reduce CP-induced nephrotoxicity in rats by administering melatonin, an antioxidant. METHODS: Male Sprague-Dawley rats were divided into different groups and were treated as follows: (1) saline control; (2) CP (16 mg/kg, i.p.); (3) CP plus melatonin (10 mg/kg, i.p.). The rats were sacrificed at the 6th day after CP treatment. To evaluate renal damage, BUN, serum creatinine, creatinine clearance and microscopic examination were done. Hydrogen peroxide which is one of the oxygen free radicals, and malondialdehyde which is known as a marker of the oxygen free radical mediated injury, and the activities of the antioxidant enzymes such as superoxied dismutase, catalase, and glutathione peroxidase were also measured. RESULTS: CP-treated rats showed the increase of BUN, serum creatinine, malondialdehyde, hydrogen peroxide and superoxide dismutase (SOD) in kidney. And CP-treated rats also showed the decrease of creatinine clearance and catalase levels. CP-treated rats showed severe tubular necrosis in proximal convoluted tubules under the light microscopic examination. The light microscopic finding and all of the parameters except SOD were restored in the rats injected with CP plus melatonin than those with CP alone. SOD level was higher in the rats injected with CP plus melatonin than that with CP alone. CONCIUSION: These results suggest that melatonin suppresses CP-induced nephrotoxicity by suppressing the production of reactive oxygen species via the activation of SOD and catalase.
Animals ; Catalase ; Cisplatin* ; Creatinine ; Free Radicals ; Glutathione Peroxidase ; Humans ; Hydrogen Peroxide ; Kidney ; Male ; Malondialdehyde ; Melatonin* ; Necrosis ; Oxidative Stress ; Oxygen ; Rats ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; Superoxide Dismutase

BACKGROUND: Coenzyme Q10 is an endogenous lipid soluble antioxidant that scavenges reactive oxygen species (ROS) directly, inhibits biomolecule oxidation, and affects antioxidant defense in vivo. Kinetin (N6-furfuryladenine) belongs to the family of N6-substituted adenine derivatives known as cytokinins. Kinetin also exerts anti-aging effects. Commercial products of coenzyme Q10 and kinetin are developed and are selling as a rejuvenating drug. However, the action mechanisms of kinetin are not fully known, though it has been suggested to act both as an inhibitor of reactive oxygen species (ROS) formation and as a scavenger of ROS. Thioctic acid (alpha-Lipoic acid), which becomes a powerful antioxidant in its reduced form, has been suggested as a dietary supplement to treat diseases associated with excessive oxidant stress. Exposure of the skin to ultraviolet (UV) radiation, particulary UVB (290-320nm), causes adverse biological effects, including alterations in cutaneous immune cells, photoaging and photocarcinogenesis. Several studies have shown that coenzyme Q10, kinetin, and thioctic acid afforded the protection effects against UVB-induced inflammatory responses and photoaging. Objective and Method: In this study, we investigated the effects of coenzyme Q10, kinetin and thioctic acid on UVB irradiated human skin fibroblasts using a viability test, thiobarbituric acid assay and Northern blot analysis. RESULT: Cell survival curves after UVB irradiation showed a dose dependent decremental pattern by trypan blue exclusion assay. Only 30% of dermal fibroblasts survived at 150mJ/cm2 UVB irradiation. The damage was associated with cell membrane lipid peroxidation, as shown by accumulation malondialdehyde (MDA). By pre-cultivation with coenzyme Q10, kinetin and thioctic acid, a significant protection effect was noted as an increase in the absolute number of surviving cells and marked decrease in the levels of MDA. CONCLUSION: Coenzyme Q10, kinetin, and thioctic acid, which have been newly accepted as having UV protection properties, are effective membrane peroxidation inhibitors and inhibitors of reactive oxygen species (ROS) formation and scavenger of ROS.
Humans ; Oxidants

BACKGROUND AND OBJECTIVES: Cisplatin (CP), an antitumor agent widely used in the treatment of head and neck cancers, has side effects such as ototoxicity and nephrotoxicity. These side effects are closely related to oxidative stress. In the present study, we attempted to suppress CP-induced ototoxicity in rats by administering melatonin, an antioxidant. MATERIALS AND METHOD: Male Sprague-Dawley rats were divided into different groups and were treated as follows: 1) saline control, 2) CP (16 mg/kg, i.p.), 3) CP plus melatonin (10 mg/kg, i.p.). The rats were sacrificed at the 6th day after CP treatment. RESULTS: CP-treated rats showed increase in cochlear malondialdehyde, hydrogen peroxide, glutathione peroxidase and glutathione reductase levels, and the decrease in cochlear superoxide dismutase (SOD) and catalase levels. CP-treated rats showed markedly decreased in the number of stereocilia on the inner hair cells and mildly decreased in the number of outer hair cells in organ of Corti under the light and scanning electron microscopic examination. Light and electron microscopic findings, and cochlear hydrogen peroxide, malondialdehyde, SOD, catalase, glutathione peroxidase and glutathione reductase levels were restored in the rats injected with CP plus melatonin than those with CP alone. CONCLUSION: These results suggest that melatonin suppresses CP-induced ototoxicity via the suppression of the increased production of reactive oxygen species.
Animals ; Catalase ; Cisplatin* ; Glutathione Peroxidase ; Glutathione Reductase ; Hair ; Head ; Humans ; Hydrogen Peroxide ; Male ; Malondialdehyde ; Melatonin* ; Neck ; Organ of Corti ; Oxidative Stress ; Rats* ; Rats, Sprague-Dawley ; Reactive Oxygen Species ; Stereocilia ; Superoxide Dismutase