Seizure-related Brain Injuries in Organophosphate Poisoning

Hur, Gyeung-Haeng,Lee,Yong-Soon,Han, Byung-Gon,Yeon, Gyu-Baek,Kim, Yun-Bae Korean Society of ToxicologyKorea Environmental Mu 1997 Toxicological Research Vol.13 No.3

The features of seizure-related brain injuries in rats poisoned i.p. with diisopropylfiuorophosphate were investigated. Pyridostigmine bromide (0.1 mg/kg) and atropine methylnitrate (20 mg/kg), which are centrally inactive, were pretreated i.m. 30 min and 10 min, respectively. before diisopropylfluorophosphate (10 mg /kg, $2LD_50$) poisoning to reduce the mortality and eliminate peripheral signs. Diisopropylfluorophosphate induced severe limbic seizures, and early necrotic and delayed apoptotic brain injuries. The necrotic brain injury, which was closely related to seizure intensity, was exerted as early as 1 hr predominently in hippocampus and piriform cortex. showing spongiform change (malacia) of neurophils in severe cases, in contrast to a typical apoptotic (TUNEL-positive)pattern after 12 hr in thalamus, and a mixed type in amygdala. Nitric oxide content in cerebrospinal fiuid significantly increased after 2 hr, reaching a maximal level at 6 hr. Pretreatment with $_L-N^G$-nitroarginine, an inhibitor of nitric oxide synthase, reduced nitric oxide content and attenuated only apoptotic brain injury in all four brain regions examined without affecting seizure intensity and necrotic injury. Taken together, early necrotic and delayed apoptotic brain injuries induced by diisopropylfiuorophosphate poisoning in rats may be related to seizure intensity and nitric oxide production, respectively.

2-Chloroethylethyl Sulfide Induces Apoptosis and Necrosis in Thymocytes

Hur,Gyeung-Haeng,Kim,Yun-Bae,Shin,Sungho The Korea Science and Technology Center 1998 BMB Reports Vol.31 No.2

2-chloroethylethyl sulfide (CEES) is an alkylating agent that readily reacts with a wide variety of biological molecules causing metabolic abnormality. The mechanism of cell death during CEES injury is poorly understood. We have examined the effect of exposure of thymocytes with various concentrations of CEES to determine the pattern of cell death in thymocytes injury induced by CEES. In the present study, we show that two patterns of cell death occurred by either one of two mechanisms: apoptosis and necrosis. Exposure to low levels of CEES (100μM) for 5 h caused an induction of apoptosis on thymocytes, as identified by the following criteria: DNA fragmentation visualized by the characteristic “ladder” pattern was observed upon agarose gel electrophoresis and morphological features were revealed by microscopical observations. In contrast, exposure to high levels of CEES (500μM) induce necrotic features such as cell lysis. Thus, depending on the concentrations, CEES can result in either apoptotic cell damage. Our findings suggest that thymocytes which are not killed directly, but merely injured by low levels of CEES, are able to activate an internally-programmed cell death mechanism, whereas thymocytes receiving severe damages apparently can not.

2-Chloroethylethyl Sulfide Induces Apoptosis and Necrosis in Thymocytes

Hur, Gyeung-Haeng,Kim, Yun-Bae,Shin, Sung-Ho Korean Society for Biochemistry and Molecular Biol 1998 Journal of biochemistry and molecular biology Vol.31 No.2

2-chloroethylethyl sulfide (CEES) is an alkylating agent that readily reacts with a wide variety of biological molecules causing metabolic abnormality. The mechanism of cell death during CEES injury is poorly understood. We have examined the effect of exposure of thymocytes with various concentrations of CEES to determine the pattern of cell death in thymocytes injury induced by CEES. In the present study, we show that two patterns of cell death occurred by either one of two mechanisms: apoptosis and necrosis. Exposure to low level of CEES (100 ${\mu}M$) for 5 h caused an induction of apoptosis on thymocytes, as identified by the following criteria: DNA fragmentation visualized by the characteristic "ladder" pattern was observed upon agarose gel electrophoresis and morphological features were revealed by microscopical observations. In contrast, exposure to high levels of CEES (500 ${\mu}M$) induce necrotic features such as cell lysis. Thus, depending on the concentrations, CEES can result in either apoptotic or necrotic cell damage. Our findings suggest that thymocytes which are not killed directly, but merely injured by low levels of CEES, are able to activate an internally-programmed cell death mechanism, whereas thymocytes receiving severe damages apparently can not.

Physostigmine 과 Procyclidine 으로 구성된 복합예방제의 유기인제 해독효능

허경행(Gyeung Haeng Hur),천기철(Ki Cheol Cheon),피택산(Taek San Phi),김지천(Jee Cheon Kim),홍대식(Dea Sik Hong),박훈(Hoon Park),정창희(Chang Hee Jung),이용한(Yong Han Lee),김윤배(Yun Bae Kim) 한국응용약물학회 2001 Biomolecules & Therapeutics(구 응용약물학회지) Vol.9 No.1

N/A Antidotal efficacy of combinational prophylactics composed of physostigmine plus procyclidine, alone or in combination with antidotes such as atropine plus 2-pralidoxime or atropine plus HI-6, was evaluated in rats. Physostigmine (0.1 mg/kg) plus procyclidine (3 mg/kg), pretreated subcutaneously 30 min prior to subcutaneous exposure to organophosphates of militarily importance, exerted protection ratios of 7.2, 6.5, 4.0, 2.9 and 8.0 fold for tabun, sarin, soman, cyclosarin and V-agent, respectively. In comparison, low effects (1.7 fold for soman and 1.3 fold for cyclosarin) were achieved with the traditional antidotes atropine (17.4 mg/ kg) plus 2-pralidoxime (30 mg/kg) administered intramuscularly immediately after organophosphate, in contrast to high effects (5.5 fold for soman and 160.0 fold for cyclosarin) with atropine (17.4 mg/kg) plus HI-6 (125 mg/kg), although the protection ratio markedly decreased when treatment of antidotes was delayed. Noteworthy, the combinational prophylactics markedly potentiated the effects of antidotes to higher than 5.0 fold in all cases. In addition, the combinational prophylactics fully prevented the seizures and excitotoxic brain injuries induced by a high dose (100 mg/kg, 1.3 LD_(50)) of soman. Taken together, it is suggested that the prophylactics composed of physostigmine and procyclidine, in combination with posttreatment antidotes, could be a promising regimen for the prevention of lethality, seizures and brain injuries induced by organophosphates possessing diverse properties.

Molecular evolutionary characterization of dengue viruses type 1 and 4 in korean travelers

Eun-Ha Hwang,Gyeung Haeng Hur,Green Kim,Hanseul Oh,Jung Joo Hong,Bon-Sang Koo 한국실험동물학회 2020 한국실험동물학회 학술발표대회 논문집 Vol.2020 No.7

Seizure-related Encephalopathy in Rats Intoxicated with Diisopropylfluorophosphate

Kim, Yun-Bae,Hur, Gyeung-Haeng The Korean Society of Toxicology Korea Environment 2001 Toxicological Research Vol.17 No.2

The incidence and distribution of necrotic and apoptotic neural cells, and activated astrocytes in the brain of rats intoxicated intra peritoneally with diisopropylfluorophosphate were investigated. Pyridostigmine bromide (0.1 mg/kg) and atropine methylnitrate (20 mg/kg) were pretreated intramuscularly 30 min and 10 min, respectively, prior to diisopropylfluorophosphate (4-10 mg/kg) administration. Diisopropylfluorophosphate induced severe limbic seizures, early necrotic and delayed apoptotic brain injuries, and rapid astrocytic responses. The necrosis, which was closely related to seizure intensity, was observed as early as 1 hr after intoxication predominently in hippocampal pyramidal cells, cerebellar Purkinje cells and neurons in pyriform/entorhinal cortices, showing malacia of neurophils. In contrast, apoptosis started to appear 12 hr after intoxication in neurons in thalamus, amygdala and neocortex, and ephendymal cells surrounding the 4th ventricle. Since marked apoptosis was induced in rats exhibiting relatively-low seizure intensity, the degree of necrosis and apoptosis was shifted to each type of injury according to the seizure intensity. Activated astrocytes, observed within 1 hr along the limbic system, were suggested to affect the neural injury patterns by producing high level of nitric oxide. However, the distribution of activated astrocytes was not in parallel with those of necrotic or apoptotic injuries, implying that the astrocytic responses resulted from seizure activity rather than neural injuries. Furthermore, astrocytes in malacic tissues disappeared during the severe limbic seizures. Therefore, it would be one of the cautionary notes on the expression of glial fibrillary acidic protein in astrocytes as a biochemical marker of brain injuries following acute exposure to organophosphates.

Protective Effect of Aminoglycosides and Their Combinations Against 2-Chloroethylethyl Sulfide Exposure

Kim, Yun-Bae,Hur, Gyeung-Haeng,Choi, Dae-Sung,Shin, SungHo,Cha, Seung-Hee,Park,Yong-Keun,Sok, Dai-Eun Korean Society of ToxicologyKorea Environmental Mu 1997 Toxicological Research Vol.13 No.1

Exposure of splenocytes to 2-chloroethylethyl sulfide (CEES) resulted in the cell death, and the cytotoxicity of CEES was prevented by inhibitors of lysosomal hydrolases. Therefore, it has been postulated that the cytotoxicity of CEES may be partially due to the lysosomal labilization. This study, based on this mechanism, was undertaken to determine whether aminoglycoside antibiotics as inhibitors of lysosomal phospholipases and their combinations with other lysosome stabilizers can be useful as a treatment to reduce the CEES toxicity in mice. 2-Chloroethylethyl sulfide (20 mg/kg body weight) was injected ip into female ICR mice, and candidate compounds were administered ip before or after the CEES challenge. Kanamycin (40 mg/kg body weight) as effective as deferoxamine (100 mg/kg body weight) enhanced the survival rate after 5 days of intoxication from 10% of control to 50 - 60%. The most effective was found to be the combination of kanamycin, cycloheximide, deferoxamine and dextrose showing an almost full protection against 2LD50 of CEES. Consistent with the protection of the CEES toxicity, the decrease of body weight in mice intoxicated with CEES was effectively prevented by kanamycin or its combinations. It is suggested that kanamycin or its combination (kanamycin, cycloheximide, deferoxamine and dextrose) would be one of effective antidotes against the CEES poisoning in mice.

Protective Effect of Aminoglycosides and their Combinations Against 2-Chloroethylethyl Sulfide Exposure

Kim, Yun-Bae,Hur, Gyeung-Haeng,Choi, Dae-Sung,Shin, Sungho,Cha, Seung-Hee,Park, Yong-Keun,Sok, Dai-Eun 충남대학교 약학대학 의약품개발연구소 1997 藥學論文集 Vol.13 No.-

Exposure of splenocytes to 2-chloroethylethyl sulfide (CEES) resulted in the cell death, and the cytotoxicity of CEES was prevented by inhibitors of lysosomal hydrolases. Therefore, it has been postulated that the cytotoxicity of CEES may be partially due to the lysosomal labilization. This study, based on this mechanism, was undertaken to determine whether aminoglycoside antibiotics as inhibitors of lysosomal phospholipases and their combinations with other lysosome stabilizers can be useful as a treatment to reduce the CEES toxicity in mice. 2-Chloroethylethyl sulfide (20 ㎎/㎏ body weight) was injected ip into female ICR mice, and candidate compounds were administered ip before or after the CEES challenge. Kanamycin (40 ㎎/㎏ body weight) as effective as deferoxamine (100 ㎎/㎏ body weight enhanced the survival rate after 5 days of intoxication from 10% of control to 50 - 60%. The most effective was found to be the combination of kanamycin, cycloheximide, deferoxamine and dextrose showing an almost full protection against 2LD50 of CEES. Consistent with the protection of the CEES toxicity, the decrease of body weight in mice intoxicated with CEES was effectively prevented by kanamycin or its combinations. It is suggested that kanamycin or its combination (kanamycin, cycloheximide, deferoxamine and dextrose) would be one of effective antidotes against the CEES poisoning in mice.

Organophosphate-induced brain injuries

Kim, Yun-Bae,Hur, Gyeung-Haeng,Shin, Sungho,Sok, Dai-Eun,Kang, Jong-Koo,Lee, Yong-Soon 충남대학교 약학대학 의약품개발연구소 1999 藥學論文集 Vol.15 No.-

The features of organophosphate-induced brain injuries were investigated. Rats was poisoned intraperitoneally with 9 mg/kg (1.8 LD_50) of diisopropylfluorophosphate, Pyridostigmine bromide (0.1 mg/kg) and atropine methylnitrate (20 mg/kg), which are centrally inactive, were pre-treated intramuscularly to reduce the mortality and eliminate peripheral signs. Diisopropylfluorophosphate induced severe limbic seizures. and early necrotic and delayed apoptotic brain injuries. The necrotic brain injury was observed to be maximal as early as 1 h after diisopropvlftuorophosphate treatment predominently in hippocampus and piriform entorhinal cortices. showing a spongifonn change (malacia) of neuropils in severe cases. In contrast, typical apoptotic (TUNEL-positive) cells started to appear at 12 h in thalamus, and a mixed type in amygdala, Separately. nitrite/nitrate content in cerebrospinal fluid was found 10 significantly increase after 2 h, reaching a maximal level at 6 h, Pre-treatment with L-N^G-nitroarginine, an inhibitor of nitric oxide synthase, reduced nitrite/nitrate content and. noteworthy, attenuated only apoptotic brain injury in all four brain regions without affecting seizure intensity and necrotic injury. Taken together, the delayed apoptotic injury of brain induced by diisopropylfluorophosphate poisoning in rats might be mediated in pan through nitric oxide production.

Modulation of Interleukin Production in Anthrax Lethal Toxin-treated Macrophages by Melatonin and Dehydroepiandrosterone

Shin, Sung-Ho,Hur, Gyeung-Haeng,Yeon, Kyu-Baek,Kim, Yun-Bae,Park, Kyung-Jin,Park, Young-Min,Lee, Woo-Sung,Cho, Bong-Huey,Kim, Won-Yong,Chung, Sang-In,Choi, Chul-Soon Korean Society for Biochemistry and Molecular Biol 2000 Journal of biochemistry and molecular biology Vol.33 No.6

Anthrax lethal toxin, which consists of two separate protein, protective antigen (83 KDa) and lethal factor (85 KDa) is responsible for major symptoms and death from systemic infection of Bacillus anthracis. High concentrations of this toxin are cytolytic to macrophages, whereas sublytic concentrations of lethal toxin induce these cells to produce interleukin $1{\beta}$ ($IL-1{\beta}$). It is proposed that melatonin and dehydroepiandrosterone (DHEA) may play an important role in modifying immune dysfunction. In this study, we investigated whether or not melatonin and DHEA could prevent $IL-1{\beta}$ production that is induced by anthrax lethal toxin in mouse peritoneal macrophages. Treatment of melatonin or DHEA alone, as well as together, prevented the production of $IL-1{\beta}$ caused by anthrax lethal toxin. We found that melatonin at a concentration of $10^{-6}-10^{-7}$ M inhibits $IL-1{\beta}$ production induced by anthrax lethal toxin. As expect, treatment of DHEA at a concentration $10^{-6}-10^{-7}$ M also suppressed production of $IL-1{\beta}$ by lethal toxin stimulated macrophages. The results of these studies suggest that melatonin and DHEA, immunomodulators, may have an important role in reducing the increase of cytokine production in anthrax lethal toxin-treated macrophages.