• 대한추나의학회지
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• 제2권1호
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• pp.143-157
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• 2001

Objectives and Methods : To evaluate the mechanism of oxidative damage by xanthine oxydase(XO) and hypoxanthine(HX)-induced oxygen radicals, MTT assay and NR assay were carried out after the cultured mouse spinal sensory neurons were preincubated for 4 hours with various concentrations of XO/HX. And the amount of total protein. neurofilament EIA. lipid peroxidation and LDH activity were measured, to evaluate the protective effect of Herbar Chelidonii(HC) water extract on cultured spinal sensory neurons damaged by XO/HX. after the cultured mouse spinal sensory neurons were preincubated with various concentrations of HC water extract for 3 hours prior to exposure of XO/HX. Results : XO/HX decreased significantly the survival rate of the cultured mouse sensory neurons by NR assay and MTT assay In proportion to concentration and exposed time. In proportion to concentration and exposed time on cultured spinal sensory neurons, XO/HX showed the quantitative decrease of neurofilament by EIA. the decrease of total protein amount by SRB assay and the Increase of lipid peroxidation as well as LDH. HC showed the quantitative increase of neurofilament and total protein, but showed the decrease of lipid peroxidation and LDH activity against the neurotoxicity of XO/HX. Conclusions : From the above results, it is concluded that XO/HX have a neurotoxic effect on cultured spinal sensory neurons and that the herbs extract, such as HC, prevent the toxicity of XO/HX effectively in that they decrease lipid peroxidation and LDH activity.

• International Journal of Oral Biology
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• 제34권2호
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• pp.97-103
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• 2009

L-trans-pyrrolidine-2,4-dicarboxylate (PDC) is a potent inhibitor of glutamate transporters. In our current study, we investigated whether the neuronal death induced by PDC involves mechanisms other than excitotoxicity in mixed mouse cortical cultures. Cortical cultures at 13-14 days in vitro were used and cell death was assessed by measuring the lactate dehydrogenase efflux into bathing media. Glutamate and PDC both induced neuronal death in a concentration-dependent manner but the neurotoxic effects of glutamate were found to be more potent than those of PDC. Treatment with 10, 100 and 200 ${\mu}$M PDC equally potentiated 50 ${\mu}$M glutamate-induced neuronal death. The neuronal death induced by 75 ${\mu}$M glutamate was almost abolished by treatment with the NMDA antagonists, MK-801 and AP-5, but was unaffected by NBQX (an AMPA antagonist), trolox (antioxidant), BDNF or ZVAD-FMK (a pan-caspase inhibitor). However, the neuronal death induced by 200 ${\mu}$M PDC was partially but significantly attenuated by single treatments with MK-801, AP-5, trolox, BDNF or ZVAD-FMK but not NBQX. Combined treatments with MK-801 plus trolox, MK-801 plus ZVAD-FMK or MK-801 plus BDNF almost abolished neuronal death, whereas combined treatments with trolox plus ZVADFMK, trolox plus BDNF or ZVAD-FMK plus BDNF did not enhance the inhibitory action of any single treatment with these drugs. These results demonstrate that the neuronal death induced by PDC involves not only in the excitotoxicity induced by the accumulation of glutamate but also the oxidative stress induced by free radical generation. This suggests that apoptotic neuronal death plays a role in PDCinduced oxidative neuronal injury.

• Toxicological Research
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• 제31권1호
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• pp.17-23
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• 2015

Excessive manganese (Mn) in the brain promotes a variety of abnormal behaviors, including memory deficits, decreased motor skills and psychotic behavior resembling Parkinson's disease. Hereditary hemochromatosis (HH) is a prevalent genetic iron overload disorder worldwide. Dysfunction in HFE gene is the major cause of HH. Our previous study has demonstrated that olfactory Mn uptake is altered by HFE deficiency, suggesting that loss of HFE function could alter manganese-associated neurotoxicity. To test this hypothesis, Hfe-knockout ($Hfe^{-/-}$) and wild-type ($Hfe^{+/+}$) mice were intranasally-instilled with manganese chloride ($MnCl_2$ 5 mg/kg) or water daily for 3 weeks and examined for memory function. Olfactory Mn diminished both short-term recognition and spatial memory in $Hfe^{+/+}$ mice, as examined by novel object recognition task and Barnes maze test, respectively. Interestingly, $Hfe^{-/-}$ mice did not show impaired recognition memory caused by Mn exposure, suggesting a potential protective effect of Hfe deficiency against Mn-induced memory deficits. Since many of the neurotoxic effects of manganese are thought to result from increased oxidative stress, we quantified activities of anti-oxidant enzymes in the prefrontal cortex (PFC). Mn instillation decreased superoxide dismutase 1 (SOD1) activity in $Hfe^{+/+}$ mice, but not in $Hfe^{-/-}$ mice. In addition, Hfe deficiency up-regulated SOD1 and glutathione peroxidase activities. These results suggest a beneficial role of Hfe deficiency in attenuating Mn-induced oxidative stress in the PFC. Furthermore, Mn exposure reduced nicotinic acetylcholine receptor levels in the PFC, indicating that blunted acetylcholine signaling could contribute to impaired memory associated with intranasal manganese. Together, our model suggests that disrupted cholinergic system in the brain is involved in airborne Mn-induced memory deficits and loss of HFE function could in part prevent memory loss via a potential up-regulation of anti-oxidant enzymes in the PFC.

• Natural Product Sciences
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• 제9권1호
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• pp.22-27
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• 2003

This study was designed to investigate the effects of main constituents of Nigella sativa (NS) seed on the survival and CNS responses in experimental animals. The toxicological investigations were conducted for the determination of median lethal doses $(LD_{50})$ of NS seed constituents [i.e. aqueous extract (AE), fixed oil (FO), volatile oil (VO)] and main components of its VO [i.e. thymoquinone (TQ), ${\alpha}-pinene$ (AP) and p-cymene (PC)]. A part of this study includes evaluation NS constituents in the induction of minimal neurological deficit (MND) as a parameter for neurotoxicity using chimney test. In this study, the i.p. $LD_{50}$ values of AE, FO, VO, TQ (suspended In 0.5%CMC), TQ (dissolved in corn oil), AP and PC, were 3020, 3371, 1853, 616.6, 90.3, 1726 and 1523 mg/kg, respectively. All the NS constituents can be considered moderately toxic ($LD_{50}$ ranged from 616.6 to 3371 mg/kg), except the oily solution of TQ, which was very toxic ($LD_{50}$ was 90.3 mg/kg). It appeared that the toxicity of the whole VO is mainly due to its content of TQ and to some extent PC. All the NS constituents induced different degrees of MND at certain dose levels. The median neurotoxic (or sedating) doses $(TD_{50})$ of AE, FO, VO, TQ (suspended in CMC) and AP and PC, were 950, 1403, 306, 88.1, >173 and 368 mg/kg, respectively. TQ was the most potent component in inducing MND, whereas the FO and AE were the least. Neurotoxicity induced by the VO in the chimney test may refer basically to its contents of TQ and to some extent PC and AP.

• International Journal of Oral Biology
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• 제36권3호
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• pp.123-128
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• 2011

The notion that dental amalgam is a potential source of mercury exposure remains a controversial issue. However, there are few epidemiological analyses that have addressed whether this occurs in children. We aimed in our current study to identify the relationship between dental amalgam filling surfaces and the blood mercury levels in a cohort of 711 South Korean children aged between 8-9 years. Oral examinations were conducted to detect the number of amalgam filling surfaces on the teeth of these individuals. Blood samples were also taken from these children to assess the levels of mercury accumulation in the body. The amalgam filling surfaces were classified into four groups based on their number: 0 (n = 368), 1-5 (n = 219), 6-10 (n = 89), and 11+ (n = 35). The blood mercury levels in the children with more than 10 amalgam surfaces was 0.47 ${\mu}g$/L higher on average than those with no amalgam surfaces after adjusting for the frequency of fish or seafood consumption, age, and gender (P < 0.05). We found from our data that a higher number of dental amalgam fillings correlated with a higher blood mercury level in Korean children. Further studies are needed to investigate whether these elevated mercury levels exert neurotoxic or nephrotoxic effects.

• Journal of Preventive Medicine and Public Health
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• 제26권2호
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• pp.282-292
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• 1993

Neurotoxicity in the workplace may occur with exposure to scores of chemicals. Although large acute outbreaks of the occupational neurological disease are rare, the incidence of occupational neurotoxicity in its subtler aspects is unknown. A working knowledge of both the major occupational neurotoxic solvents and the tools used by cliniical neurologists and neurotoxicologists to evaluate neurotoxicity in working populations is a necessity fur the occupational physician. To investigate the effects of carbon disulfide($CS_2$) on the peripheral nerve system using the nervous conduction study, 105 male workers working in the spinning room of a viscose rayon factory were examined and compared with a sex and age matched, unexposed 105 male controls using t-test analysis. 72.4% of $CS_2$-exposed workers complained of neurological symptoms, and the abnormal cases in nerve conduction study were 48.6%. The abnormal cases of nerve conduction study increased in number according as the age and duration of exposure increased. In this study, asymptomatic workers were confirmed to have subclinical neuropathy by nerve conduction study. Also as there were abnormal cases even in its duration of exposure below 4 years, nerve conduction study turned out to be ways of discovering of early peripheral neuropathy. In nerve conduction study, the amplitude, velocity, F-wave latency and H-reflex of the motor and sensory nerves in both upper and lower extremities were significant different between $CS_2$-exposed workers and the controls. From the pathological viewpoint, both segmental and axonal degenerations were assumed in this study.

• Toxicological Research
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• 제35권1호
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• pp.83-91
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• 2019

Nanoparticles (NPs) have been recognized as both useful tools and potentially toxic materials in various industrial and medicinal fields. Previously, we found that zinc oxide (ZnO) NPs that are neurotoxic to human dopaminergic neuroblastoma SH-SY5Y cells are mediated by lipoxygenase (LOX), not cyclooxygenase-2 (COX-2). Here, we examined whether human bone marrow-derived mesenchymal stem cells (MSCs), which are different from neuroblastoma cells, might exhibit COX-2- and/or LOX-dependent cytotoxicity of ZnO NPs. Additionally, changes in annexin V expression, caspase-3/7 activity, and mitochondrial membrane potential (MMP) induced by ZnO NPs and ZnO were compared at 12 hr and 24 hr after exposure using flow cytometry. Cytotoxicity was measured based on lactate dehydrogenase activity and confirmed by trypan blue staining. Rescue studies were executed using zinc or iron chelators. ZnO NPs and ZnO showed similar dose-dependent and significant cytotoxic effects at concentrations ${\geq}15{\mu}g/mL$, in accordance with annexin V expression, caspase-3/7 activity, and MMP results. Human MSCs exhibited both COX-2 and LOX-mediated cytotoxicity after exposure to ZnO NPs, which was different from human neuroblastoma cells. Zinc and iron chelators significantly attenuated ZnO NPs-induced toxicity. Conclusively, these results suggest that ZnO NPs exhibit both COX-2- and LOX-mediated apoptosis by the participation of mitochondrial dysfunction in human MSC cultures.

• 한국정보통신학회:학술대회논문집
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• 한국정보통신학회 2022년도 춘계학술대회
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• pp.270-272
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• 2022

임상을 거친 약물이 시중에 유통되지 못하는 요인 중 하나는 안전성이다. 약물 부작용으로 인해 발생하는 안전성 문제의 주된 원인인 신경독성의 경우, 사전에 약물이나 화합물에 대한 위험 평가가 필요하다. 현재 약물의 안전성 검사를 위한 실험들은 동물 실험을 기반으로 하고 있으며, 이는 시간과 비용이 많이 든다는 단점을 갖는다. 따라서 위 문제를 해결하기 위해 in silico 실험을 통한 신경독성 예측모델을 제안하고자 한다. 본 연구에서는 의학 언어 시스템 (Unified Medical Language System)을 이용해 신경독성의 범주를 확대하고, 통합 데이터베이스를 기반으로 다양한 관련 화합물 데이터를 얻었다. 얻은 화합물들의 SMILES (Simplified Molecular Input Line Entry System)를 fingerprint로 변환시키고 이를 사용한 기계학습 기반의 모델을 만들었다. 모델은 최종적으로 신경독성의 유무를 예측한다. 해당 연구에서 제안된 실험은 in vivo 실험에 소요되는 시간 및 비용을 줄일 수 있다. 더 나아가 신약 개발 연구 기간을 단축하고 개발 중지 등의 부담을 줄일 수 있을 것으로 기대된다.

• 한국미생물·생명공학회지
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• 제52권1호
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• pp.44-54
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• 2024

One of the serious modern environmental problems is pollution caused by highly toxic pesticides. Only small amounts of applied pesticides reach their target, and the rest ends up in soil and water. Chlorpyrifos is a toxic, broad-spectrum organophosphate insecticide. In humans, chlorpyrifos inhibits acetylcholinesterase (AChE) in the peripheral and central nervous system, and particularly in children, small amounts of this pesticide cause neurotoxic damage. As the toxic effects of chlorpyrifos and its persistence in the environment require its removal from contaminated sites, it is essential to study the biological diversity of chlorpyrifos-degrading microorganisms. In this study, we sought to determine the chlorpyrifos-degrading ability of the bacterial strain Ochrobactrum intermedium PDB-3. This strain was isolated from soil contaminated with various pesticides and identified as PDB-3 based on morpho-cultural characteristics, MALDI-TOF MS, and 16S rRNA. Studies were conducted for 30 days in sterile soils containing initial concentrations of 50, 75, 100, and 125 mg/kg of chlorpyrifos. To determine the degradation of chlorpyrifos, a liquid culture of the strain was added to the soil at three optical densities: 0, and after 24 and 48 h (OD = 0.03, 0.2 and 0.32). Using GX-MS, we determined that chlorpyrifos was converted to 3,5,6-trichloro-2-pyridinol (TCP). We also found that with increasing optical density, rapid degradation of the initial concentration of chlorpyrifos occurred. Sterile soil without strain PDB-3 was used as a control sample.

• The Korean Journal of Physiology and Pharmacology
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• 제13권4호
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• pp.273-279
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• 2009

The accumulation of ${\beta}$-amyloid (A${\beta}$) aggregates is a characteristic of Alzheimer's disease (AD). Furthermore, these aggregates have neurotoxic effects on cells, and thus, molecules that inhibit A${\beta}$ aggregate formation could be valuable therapeutics for AD. It is well known that aggregation of A${\beta}$ depends on its hydrophobicity, and thus, in order to increase the hydrophilicity of A${\beta}$, we considered using citrate, an anionic surfactant with three carboxylic acid groups. We hypothesized that citrate could reduce hydrophobicity and increase hydrophilicity of A${\beta}_{1-40}$ molecules via hydrophilic/electrostatic interactions. We found that citrate significantly inhibited A${\beta}_{1-40}$ aggregation and significantly protected SH-SY5Y cell line against A${\beta}_{1-40}$ aggregates-induced neurotoxicity. In details, we examined the effects of citrate on A${\beta}_{1-40}$ aggregation and on A${\beta}_{1-40}$ aggregates-induced cytotoxicity, cell viability, and apoptosis. Th-T assays showed that citrate significantly inhibited A${\beta}_{1-40}$ aggregation in a concentration-dependent manner (Th-T intensity: from 91.3% in 0.01 mM citrate to 82.1% in 1.0 mM citrate vs. 100.0% in A${\beta}_{1-40}$ alone). In cytotoxicity and viability assays, citrate reduced the toxicity of A${\beta}_{1-40}$ in a concentration-dependent manner, in which the cytotoxicity decreased from 107.5 to 102.3% as compared with A${\beta}_{1-40}$ aggregates alone treated cells (127.3%) and the cell viability increased from 84.6 to 93.8% as compared with the A${\beta}_{1-40}$ aggregates alone treated cells (65.3%). Furthermore, Hoechst 33342 staining showed that citrate (1.0 mM) suppressed A${\beta}_{1-40}$ aggregates-induced apoptosis in the cells. This study suggests that citrate can inhibit A${\beta}_{1-40}$ aggregation and protect neurons from the apoptotic effects of A${\beta}_{1-40}$ aggregates. Accordingly, our findings suggest that citrate administration should be viewed as a novel neuroprotective strategy for AD.