Prevention of activation

Acetaminophen, which depletes hepatic glutathione, does not potentiate the toxicity of methyl parathion in mice. A possible mechanism of action may be competition between acetaminophen and methyl parathion for mixed function oxidases and subsequent prevention of activation of methyl parathion to methyl paraoxon (Costa and Murphy 1984). Diethyl maleate, an agent that depletes cytosolic glutathione and is not an enzyme inducer, potentiates toxicity of methyl parathion in mice (Mirer et al. 1977). 

Treatment of latent tuberculosis infection (LTBI) with isoniazid (INH) is very effective in preventing persons infected with M. tuberculosis from developing tuberculosis, regardless of HIV-1 serostatus. Several recent studies have shown that rifampicin and pyrazinamide taken for 2 months is as effective as 6-12 months of INH for the prevention of active TBC in HIV-1 seropositive persons although more hepatotoxicity is seen. 

The proteasome is a large multisubunit proteolytic complex that participates in the degradation of proteins critical for cell cycle regulation. The proteasome inhibitors can overcome drug resistance. This effect is thought to be mediated through prevention of activation of NF-kB (nuclear transcription factor-icB) by proteasome inhibition. NF-kB is considered as one of the key factors involved in apoptotic pathways... 

Branisteanu, D.D. et al. (1993) Partial prevention of active Heymann nephritis by la,25-dihydroxyvitamin D3. Clinical and Experimental Immunology, 94, 412-417. 

Most kinase screens follow inhibition of catalysis by enzymes in their activated states. An alternative assay format is required to identify and characterise compounds that function by prevention of activation. Here, the target kinase is used as a substrate for an upstream activating kinase. This assay accordingly also identifies compounds, which inhibit the upstream... 

In some cases, it is important to characterise the effects of compounds on different activation states of the same kinase. Compounds may give prevention of activation by binding to non-activated kinase in addition to inhibition of catalysis by association the activated state. Some compounds show marked changes in affinity according to the kinase activation state. The magnitude of any effect varies considerably between kinases and tends to be similar for inhibitors that bind the same kinase conformation.13,30,37... 

This barrier refers to measures, such as locks doors etc, which prevent access to active parts. Improper access prevention of active parts can lead to violation of the safe... 

Access Prevention of active parts Ignored access prevention 0.06 ... 

Access Prevention of active parts no procedure to prevent unauthorized persons working on low/high voltage systems 0.16 0.21... 

Active errors are those errors that have immediate, observable, undesirable outcomes and can be either acts of commission or omission. The majority ofinitiatingactions are active errors. Therefore, a strategic approach to preventing events should include the anticipation and prevention of active errors. 

To avoid these problems, refiners commonly use additives called detergents" (Hall et al., 1976), (Bert et al., 1983). These are in reality surfactants made from molecules having hydrocarbon chains long enough to ensure their solubility in the fuel and a polar group that enables them to be absorbed on the walls and prevent deposits from sticking. The most effective chemical structures are succinimides, imides, and fatty acid amines. The required dosages are between 500 and 1000 ppm of active material. 

The concentration of t-PA in human blood is 2—5 ng/mL, ie, 2—5 ppb. Plasminogen activation is accelerated in the presence of a clot, but the rate is slow. The dissolution of a clot requites a week or more during normal repair of vascular damage (17). Prevention of irreversible tissue damage during a heart attack requires that a clot, formed by mpture of an atherosclerotic plaque, be dissolved in a matter of hours. This rapid thrombolysis (dissolution of the clot) must be achieved without significant tibrinogenolysis elsewhere in the patient. 

To prevent such release, off gases are treated in Charcoal Delay Systems, which delay the release of xenon and krypton, and other radioactive gases, such as iodine and methyl iodide, until sufficient time has elapsed for the short-Hved radioactivity to decay. The delay time is increased by increasing the mass of adsorbent and by lowering the temperature and humidity for a boiling water reactor (BWR), a typical system containing 211 of activated carbon operated at 255 K, at 500 K dewpoint, and 101 kPa (15 psia) would provide about 42 days holdup for xenon and 1.8 days holdup for krypton (88). Humidity reduction is typically provided by a combination of a cooler-condenser and a molecular sieve adsorbent bed. 

The temperature and humidity should be maintained at comfort conditions consistent with the operator s expected level of activity in order to minimise perspiration. Constant temperature and humidity may also be required in machine rooms to prevent the etching or corrosion of machine parts. If perspiration causes only minor damage to the product and results in few rejects, then inside design conditions at 27°C and 40% rh are satisfactory. Where even small amounts of perspiration cause extreme damage to precision-machined parts and result in a high amount of rejects, inside design conditions of 21°C and 40% rh are recommended. 

In 1956 selenium was identified (123) as an essential micronutrient iu nutrition. In conjunction with vitamin E, selenium is effective iu the prevention of muscular dystrophy iu animals. Sodium selenite is adrninistered to prevent exudative diathesis iu chicks, a condition iu which fluid leaks out of the tissues white muscle disease iu sheep and infertility iu ewes (see Eeed ADDITIVES). Selenium lessens the iacidence of pneumonia iu lambs and of premature, weak, and stillborn calves controls hepatosis dietetica iu pigs and decreases muscular inflammation iu horses. White muscle disease, widespread iu sheep and cattle of the selenium-deficient areas of New Zealand and the United States, is insignificant iu high selenium soil areas. The supplementation of animal feeds with selenium was approved by the U.S. EDA iu 1974 (see Eeed additives). Much of selenium s metaboHc activity results from its involvement iu the selenoproteia enzyme, glutathione peroxidase. 

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