This study explored the health hazard of those exposed to methylene chloride by assessing its atmospheric concentration when a tear gas mixture was aerially dispersed. The concentration of methylene chloride ranged from 311.1-980.3 ppm (geometric mean, 555.8 ppm), 30 seconds after the dispersion started. However, the concentration fell rapidly to below 10 ppm after dispersion was completed. The concentration during the dispersion did not surpass the National Institute for Occupational Safety and Health 'immediately dangerous to life or health' value of 2,300 ppm, but did exceed the American Conference of Governmental Industrial Hygienists excursion limit of 250 ppm. Since methylene chloride is highly volatile (vapor pressure, 349 mmHg at 20degrees C), the postdispersion atmospheric concentration can rise instantaneously. Moreover, the o-chlorobenzylidenemalononitrile formulation of tear gas (CS gas) is an acute upper respiratory tract irritant. Therefore, tear gas mixtures should be handled with delicate care.
Methylene Chloride ; National Institute for Occupational Safety and Health (U.S.) ; o-Chlorobenzylidenemalonitrile ; Respiratory System ; Tear Gases

The effects of tear gas, o -chlorobenzylidene malononitrile (CS) on the cytoplasmic organelles were studied in the ciliated cell of rat tracheal epithelium. Albino rats (Sprague -Dawley strain), weighing about 150gm, were used as experimental animals. The experimental animals were exposed to 2.0 g/m 3 of CS gas for 20 minutes per day for the succesive 3 days. The experimental animals were sacrified at 1, 3, 6, 12 hours and 1, 3 and 5 days after final exposure to CS gas. Specimens obtained from the trachea were pre -fixed in 2% glutaraldehyde -2.5% paraformaldehyde and post -fixed in the 1% osmium tetroxide for electron microscopic study. The results obtained were as follows: 1. In 1 hour CS gas exposed group, rough endoplasmic reticulum with dilated cisternae, and mitochondria with disrupted double membrane in the ciliated cells are found. 2. In 3 hours and 6 hours CS gas exposed groups, dilated, segmented and sacculated cisterane of rough endoplasmic reticulum, mitochondria with dissolved cristae and disrupted double membrane, and Golgi complex with atrophied cisternae are observed in the ciliated cell. 3. In 12 hours CS gas exposed group, some mitochondria with swollen cristae is found in the ciliated cell. 4. In 1 day CS gas exposed group, mitochondria with dissolved cristae, Golgi complex with hypertrophied cisternae, and autophagic vacuole are found. 5. In 3 day and 5 day CS gas exposed groups, numerous mitochondria, well -developed rough endoplasmic reticulum, and supranuclear Golgi complex are found in ciliated cell. The results of the present study suggest that the o -chlorobenzylidene malononitrile (CS) gas is cytotoxic to the ciliated cells in tracheal epithelium inducing some degenerative changes, which are recovered with the lapse of time.
Animals ; Cytoplasm* ; Endoplasmic Reticulum, Rough ; Epithelium* ; Glutaral ; Golgi Apparatus ; Membranes ; Mitochondria ; Organelles* ; Osmium Tetroxide ; Rats* ; Tear Gases ; Trachea ; Vacuoles

OBJECTIVESTo explore relationship between rat brain tissues hurts of gas explosion and the expression of Protein Kinase C alpha mRNA.

METHODSBuild up rat hurt model of gas explosion. In Situ Hybridization (IDH) technique was used to test Protein Kinase C alpha mRNA. Immunohistochemical Assays (IHA) was used to determine c-fos gene protein.

RESULTSOnly a little a mount expression of PKC alpha mRNA and c-fos of the control group was detected. The expression of the cerebral cortex and hippocampus of PKC alpha mRNA 24 h, 48 h and the 48 h increased obviously, and the 48 h reached the peak of expression; (t = 4.12 P < 0.01). The expression of c-fos protein of the cerebral cortex and hippocampus started to increase obviously at 0.5 h and the 4 h reached the peak, then the strength lowered gradually and the expression level came back normal level on fifth day.

CONCLUSIONThe anoxia of brain tissues due to the gas explosion may promote the expression of PKCamRNA, and PKCamRNA could regulate the expression of the gene of c-fos. Both PKCamRNA and the gene of c-fos are involved in harmful processes to the nerve cells.

Animals ; Brain ; metabolism ; Brain Injuries ; metabolism ; Disease Models, Animal ; Explosions ; Hypoxia ; metabolism ; Protein Kinase C-alpha ; metabolism ; Proto-Oncogene Proteins c-fos ; metabolism ; RNA, Messenger ; genetics ; Rats ; Rats, Sprague-Dawley ; Tear Gases