• Journal of Sensor Science and Technology
• /
• v.23 no.4
• /
• pp.217-223
• /
• 2014

Nerve agents are major chemical warfare agents with the "G series" and "V series" being the most widely known because of their lethal effect. Although not conspicuously used in major wars, the potential detrimental impact on modern society had been revealed from the sarin terror attack on Tokyo subway, which affected thousands of people. In this mini-review, major nerve agents of the "G series" and "V series" have been described along with various types of their detection methods. The physical properties and hydrolysis mechanisms of the major nerve agents are discussed since these are important factors to be considered in choosing detection methods, and specifying the procedures for sample preparations in order to enhance detection precision. Various types of extraction methods, including liquid-phase, solid-phase, gas-phase and solid-phase microextraction (SPME), are described. Recent development in the use of gas sensors for detecting nerve agents is also summarized.

• Bulletin of the Korean Chemical Society
• /
• v.30 no.1
• /
• pp.49-52
• /
• 2009

Single-drop microextraction (SDME) is an extraction methodology where the drop plays an essential role as extracts. It was evaluated for the GC-MS determination of nerve agents, one class of the chemical warfare agents (CWAs). Since these nerve agents are highly toxic, it is important to detect the nerve agents in the environmental samples. Several affecting factors including extraction solvents, stirring rate, extraction time, and amounts of salt were optimized. The limit of detections (LODs) were 0.1 - 10 ng/mL and the relative standard deviations (RSDs%, n=5) were in the range of 6.3% to 9.0% for four nerve agents. Without pretreatment of the environmental samples, 5-103 fold enrichments and 48-100% recovery were accomplished. These results demonstrated the feasibility of this method for on-site and off-site analysis of water sample collected from suspicious CWAs site.

• Restorative Dentistry and Endodontics
• /
• v.20 no.2
• /
• pp.508-526
• /
• 1995

This experiment was performed to study mechanisms of desensitization by chemical desensitizing agents in hypersensitive dentin and compare effects of these agents by measuring the activity of intradental nerves and observing their occluding aspects on dentinal tubules with SEM over time after application of chemical desensitizing agents to the exposed dentinal surfaces. Canines of adult cats weighing 2-3 kg were cross-sectioned at 1.5 mm from incisal apex, and the smear layer of the exposed dentinal susface was removed by 32 % $H_3PO_4$ for 15 sec. Chemical desensitizing agents such as 10% $SrCl_2$, 5% $KNO_3$ and 30% $K_2C_2O_4$, were applied to the exposed dentin surfaces for 2 minutes. Intradental nerve activity was measured immediately after application of the agents, at 15 minutes and at 30 minutes by stimulating with 4M NaCl. To compare occluding ability of desensitizing agents on dentinal tubules in vivo and in vitro, the structures of the exposed dentinal surfaces of nonvital and vital teeth were morphologically observed by SEM. The results obtained were as follows : 1. Intradental nerve activity was decreased immediately after the application of 10 % $SrCl_2$, 5% $KNO_3$ and 30% $K_2C_2O_4$. (p<0.01), among which 30% $K_2C_2O_4$. showed the highest desensitizing effect(p<0.01). 2. The immediately decreased intradental nerve activity after application of 10 % $SrCl_2$ and 5% $KNO_3$ was increased over time. 10% $SrCl_2$ and 5% $KNO_3$ showed no desensitizing effect respectively at 30 minutes and at 15 minutes after application. 3. The immediately decreased intradental nerve activity after application of 30 % $K_2C_2O_4$ was persistently continued during the period of observation (p<0.01). 4. Precipitates of $SrCl_2$ and $KNO_3$ were not noted on the exposed dentinal surfaces and within dentinal tubules by SEM examination. On the other hand, 30 % $K_2C_2O_4$ produced precipitates on the exposed dentinal surfaces and openings of dentinal tubules without any formed preciptates within dentinal tubules. 5. Ten percent $SrCl_2$, 5 % $KNO_3$ and 30 % $K_2C_2O_4$ showed no differences in their occluding aspects on dentinal tubules either in vivo or in vitro studies and either immediately following application or at 30 minutes. These results suggest that the desensitizing effect of $SrCl_2$ and $KNO_3$ is resulted from their reducing effect on the intradental nerve activity rather than from their precipitates' occluding the dentinal tubules. However, desensitizing effect of 30 % $K_2C_2O_4$, is probably resulted from its precipitates' occluding the openings of the dentinal tubules as well as from it's reducing effect on the intradental nerve actibity.

• Journal of the Korea Institute of Military Science and Technology
• /
• v.14 no.5
• /
• pp.920-931
• /
• 2011

Nerve agents are irreversible inhibitors of the cholinesterase enzyme. Exposure causes a progression of toxic signs, including hypersecretions, fasciculations, tremor, convulsions, respiratory distress, epileptiform seizures, brain injuries and death. A combined regimen of prophylaxis and therapy is the most effective medical countermeasure for dealing with the threat of nerve agent poisoning to military personnel. In this paper, the author investigated the updated technologies regarding various pre- and post-treatment drugs for nerve agents detoxification which are under development in several countries including Korea. Some characteristics of active ingredients in the formulations of drugs, their action mechanisms, and effectiveness were analyzed. Additionally, part of experimental data on the transdermal patch studied in ADD using beagle dogs was introduced.

• The Korean Journal of Pain
• /
• v.24 no.3
• /
• pp.164-168
• /
• 2011

Obturator nerve block has been commonly used for pain management to prevent involuntary reflex of the adductor thigh muscles. One of several options for this block is chemical neurolysis. Neurolysis is done with chemical agents. Chemical agents used in the neurolysis of the obturator nerve have been alcohol, phenol, and botulinum toxin. In the current case, a patient with spasticity of the adductor thigh muscle due to cervical cord injury had obturator nerve neurolysis done with botulinum toxin type B (BoNT-B). Most of the previous studies have used BoNT-A with only a few reports that have used BoNT-B. BoNT-B has several advantages and disadvantages over BoNT-A. Thus, we report herein a patient who successfully received obturator nerve neurolysis using BoNT-B to treat adductor thigh muscle spasm.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.9
• /
• pp.1368-1370
• /
• 2003

• Journal of the Korea Institute of Military Science and Technology
• /
• v.25 no.2
• /
• pp.210-217
• /
• 2022

Chemical warfare agents(CWA) such as nerve agents and vesicating agents show lethality by skin contamination. Skin protection, therefore, is one of the top priorities to deal with the growing threat from CWA. In an attempt to develop the most effective topical skin protectant(TSP), candidate substances including PFPE(perfluorinated polyether), PTFE(polytetrafluoroethylene), glycerin, and polysaccharides were evaluated in forms of various formulations against nerve agent simulant DMMP(dimethylmethyl phosphonate) penetration. The protective efficacy of the formulation against DMMP penetration was estimated as the onset time of color change of the KM9 chemical agent detection paper. Based on this study, it was found that several PFPE- and glycerin-based formulations exhibit remarkably superior efficacy as a protective cream. This protective cream is expected to be used as TSP for military application after further research.

• The Journal of Korean Medicine
• /
• v.33 no.3
• /
• pp.133-146
• /
• 2012

Background: Most antitumor agents have the side effect of chemotherapy-induced peripheral neuropathy (CIPN). Cancer patients who take antitumor agents suffer from CIPN, but there is no known treatment for it. Unlike the central nerve system, the peripheral nerve can self-repair, and the Schwann cell takes this mechanism. Objectives: In this study, we researched the effect of YideungJetong-Tang (YJT) extract on taxol-induced sciatic nerve damage, through in vitro and in vivo experiments. Also, we studied the effect of YJT extract on neurite recovery and anti-inflammatory effect after compression injury of sciatic nerve in vivo. Methods: Vehicle, taxol and taxol+YJT were respectively applied on sciatic nerve cells of rat in vitro, then the cells were cultured. The sciatic nerve cells and Schwann cells were then observed using Neurofilament 200, Hoechst, ${\beta}$ -tubulin, S-$100{\beta}$, caspase-3 and phospho-Erk1/2. CIPN was induced by taxol into the sciatic nerve of rat in vivo, then YJT extract was taken orally. The axons, Schwann cells and neurites of the DRG sensory nerve were then observed using Neurofilament 200, ${\beta}$-tubulin, Hoechst, S-$100{\beta}$, phospho-Erk1/2 and caspase-3. YJT was taken orally after sciatic nerve compression injury, and the changes in axon of the sciatic nerve, Schwann cells and TNF-${\alpha}$ concentration were observed. Results: The taxol and YJT treated group showed significant effects on Schwann cell recovery, neurite growth and recovery. In vivo, YJT compared with control group showed Schwann cell structural improvement and axons recovering effect after taxol-induced Schwann cell damage. After sciatic nerve compression injury, recovery of distal axon, changes of Schwann cell distribution, and anti-inflammatory response were observed in the YJT. Conclusions: Through this study, we found that after taxol-induced neurite damage of sciatic nerve in vivo and in vitro, YJT had significant effects on sciatic nerve growth and Schwann cell structural improvement. In vivo, YJT improved recovery of distal axons and Schwann cells and had an anti-inflammatory effect.

• Korean Journal of Veterinary Research
• /
• v.35 no.2
• /
• pp.237-243
• /
• 1995

The effects of various autonomic blocking agents to perivascular nerve stimulation were investigated on isolated coronary artery of pig. 1. The magnitude of contractile response to perivascular nerve stimulation increased with increasing frequency(280Hz) of stimulation. 2. The contractions to perivascular nerve stimulation(40V, 40Hz, 0.5msec, 1min) were increased by pretreatment of the cholinestrase inhibitor, physostigmine. 3. The contraction to perivascular nerve stimulation(40V, 40Hz, 0.5msec, 1min) was antagonised by the muscarinic antagonist, atropine. 4. The contraction to perivascular nerve stimulation(40V, 40Hz, 0.5msec, 1min) was blocked by the neural blocker, tetrodotoxin. 5. The contractions to perivascular nerve stimulation(40V, 40Hz, 0.5msec, 1min) were not significantly affected by the ${\alpha}$-adrenergic antagonist, phentolamine or ${\beta}$-adrenergic antagonist, propranolol. 6. The contractile response by the acetylcholine was increased by the pretreatment of cholinestrase inhibitor, physostigmine. This findings suggest that the powerful excitatory action by the perivascular nerve stimulation may be linked to muscarinic receptor by cholinergic nerve excitation in coronary artery of pig.

• Proceedings of the Korean Society for Applied Microbiology Conference
• /
• 2005.06a
• /
• pp.139-141
• /
• 2005