Short time exposure test

Kojima H, Hayashi K, Sakaguchi H, Omori T, Otoizumi T, Sozu T, Kuwahara H, Hayashi T, Sakaguchi M, Toyoda A, Goto H, Watanabe S, Ahiko K, Nakamura T, Morimoto T (2013) Second-phase validation study of short time exposure test for assessment of eye irritation potency of chemicals. Toxicol In Vitro 27 1855-1869... 

As an index for toxicity of gaseous substances, the median lethal concentration (LC 5 0 ) and the threshold limit value (TLV) are used to evaluate acute toxicity. LCso is the gas concentration (ppm) in air which results in the death of 50% of a population of test animals by inhalation. TLV is the threshold limit of exposure which does not cause any serious sickness in workers under normal conditions of an 8 hours day and a 40-48 hour work week. TLV is usually given in combination with the time-weighted-average concentrations for 8 hours per day (TLV—TWA), or with the short time exposure limit (TLV-STEL), which is that exposure which should not be exceeded even for a relatively short period (15-30 minutes), or with the ultimate limit (TLV-C), which defines the exposure level that should not be exceeded under any circumstances. 

The Short Time Exposure (STE) test uses cell viability (MTT reduction) in a rabbit corneal cell line (SIRC) to assess eye irritation potential of test substances [62], The test is based on the application of different concentrations of the test substance (5 and 0.05 %) for a short (5 min) exposure time that reflects the actual situation of exposure to a consumer product. 

Takahashi Y, Koike M, Honda H, Ito Y, Sakaguchi H, Suzuki H, Nishiyama N (2008) Development of the short time exposure (STE) test an in vitro eye irritation test using SIRC cells. Toxicol In vitro 22 760-770... 

Takahashi Y, Hayashi T, Watanabe S, Hayashi K, Koike M, Aisawa N, Ebata S, Sakaguchi H, Nakamura T, Kuwahara H, Nishiyama N (2009) Inter-laboratory study of short time exposure (STE) test for predicting eye irritation potential of chemicals and correspondence to globally harmonized system (GHS) classification. J Toxicol Sci 34 611-626... 

Sakaguchi H, Ota N, Omori T, Kuwahara H, Sozu T, Takagi Y, Takahashi Y, Tanigawa K, Nakanishi M, Nakamura T, Morimoto T, Wakuri S, Okamoto Y, Sakaguchi M, Hayashi T, Hanji T, Watanabe S (2011) Validation study of the Short Time Exposure (STE) test to assess the eye irritation potential of chemicals. Toxicol In Vitro 25 796-809... 

Subchronic Studies. Although short-term repeated exposure studies provide valuable information about toxicity over this time span, they may not be relevant for assessment of ha2ard over a longer time period. For example, the minimum and no-effects levels determined by short-term exposure may be significantly lower if exposure to the test material is extended over several months. Also, certain toxic effects may have a latency which does not allow their expression or detection over a short-term repeated-exposure period for example, kidney dysfunction or disturbances of the blood-forming tissues may not become apparent until subchronic exposure studies are undertaken. 

The American Society for Testing Materials (ASTM) recommends 250 ml of solution for every square inch of area of test metal. Exposure time is also critical. Often it is desirable to extrapolate results from short time tests to long service periods. Typically, corrosion is more intense in its early stages (before protective coatings of corrosion products build up). Results obtained from short-term tests tend to overestimate corrosion rates which often results in an overly conservative design. 

Mooney viscometer is also used to measure the time it takes, from initial exposure of the compound to a particular temperature, to the time of onset of cure at that temperature [2]. This is known as the scorch time. Scorch time is an important parameter to the rubber processor, as a short time may lead to problems of premature vulcanization. As the test is taken past the onset of cure, the rotor tears the cured rubber, and therefore this device cannot be used to investigate rheological properties after the scorch time. 

Data adequacy The key study was well conducted and documented. Supporting data include both human and animal studies. Animal studies covered acute, subchronic, and chronic exposure durations and addressed systemic toxicity as well as neurotoxicity, reproductive and developmental effects, cardiac sensitization, genotoxicity, and carcinogenicity. Other effects in animal studies occurred at much higher concentrations or with repeated exposures the latter are not relevant for setting short-term exposures. No effects other than narcosis occurred in rats and mice exposed at 200,000 ppm for various periods of time. Adjustment by a total UF of 10 results in a higher value (20,000 ppm) than from the cardiac sensitization test with dogs. ... 

Although we can measure the amount of chloroform in the air that you breathe out, and in blood, urine, and body tissues, we have no reliable test to determine how much chloroform you have been exposed to or whether you will experience any harmful health effects. The measurement of chloroform in body fluids and tissues may help to determine if you have come into contact with large amounts of chloroform. However, these tests are useful only a short time after you are exposed to chloroform because it leaves the body quickly. Because it is a breakdown product of other chemicals (chlorinated hydrocarbons), chloroform in your body might also indicate that you have come into contact with those other chemicals. Therefore, small amounts of chloroform in the body may indicate exposure to these other chemicals and may not indicate low chloroform levels in the environment. From blood tests to determine the amount of liver enzymes, we can tell whether the liver has been damaged, but we cannot tell whether the liver damage was caused by chloroform. 

Acute toxicity refers to the adverse effects, which occur within a given, usually short time, following a single, usually high exposure to a substance. In older literature, acute toxicity is sometimes used synonymously with lethal effect or LD50, which was the only endpoint in older acute toxicity tests. Nowadays, acute toxicity studies are designed to reveal more subtle effects. 

Acute dermal toxicity is the adverse effects occurring within a short time of dermal application of a single dose of a test substance. The duration of exposure in the OECD TG 402 is 24 h, at the end of which residual test substance should be removed. 

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