Poisoning laboratory tests

When a specific antidote or other treatment is under consideration, quantitative laboratory testing may be indicated. For example, determination of the acetaminophen serum level is useful in assessing the need for antidotal therapy with acetylcysteine. Serum levels of salicylate (aspirin), ethylene glycol, methanol, theophylline, carbamazepine, lithium, valproic acid, and other drugs and poisons may indicate the need for hemodialysis (Table 58-3). 

The individual hydrocarbons in the exhaust differ widely in the ease of both catalytic and noncatalytic oxidation. Thus, the poisoning effect may vary, and indeed does, with the hydrocarbon composition of the exhaust itself, and with the necessarily limited choice of particular hydrocarbons used in various laboratory tests. In many instances the hydrocarbons are... 

On some catalysts simultaneous presence of S and Pb causes deterioration to a higher degree than the separate effects of the two poisons predict, as was reported by Jackson et al. (92) for Cu-Ni and Pt-Ni reduction catalysts. In contrast, laboratory tests of a Ru reduction catalyst (82) indicated that the combined effects of Pb and S was less detrimental than the sum of their separate effects. 

We have not discussed catalyst life as one of the determinants in the selection of a catalyst, although it obviously can be of critical importance. In the absence of poisoning, hydrogenation catalysts frequently last for several years in plant service, and catalyst costs are thus relatively minor in the overall product cost breakdown. Candidate catalysts that did not exhibit exceptional life in laboratory tests were simply excluded from consideration for our purposes. 

Laboratory tests (Figure 3) (28) and commercial experience (30,31) show that the catalysts need considerable time to reach the stationary state, after which further deactivation is very slow. This is related to the high sensitivity of the catalyst to poisons, and their necessarily low concentration. 

Carbon deposition is one of the luost serious problems of the steam reforming catalyst process (ref 1). The deposition of carbon on naphtha steam reforming catalysts depends ori the chemical composition of the hydrocarbon oil, the steam/carbon ratio in the feedstock, as well as the pi ocesa temperature and pressure, it is also affected by tlie presence of sulfur poisons Our past research of SNG catalysts ejiamined the nature of the carbon deposits as a function of the sulfur level on the catalyst (refs, 2 4). A small amount of sulfur was found to promote the formation of carbon that is non-reactive with steam and hydrogen under steam reforming reaction conditions. The continuous accumulation of this less reactive carbon [continuous carbon deposition (CCD)l on the catalyst surface leads to coke fouling Studies of the occurrence of CCD in our laboratory tests allow ua to predict, that coke fouling is likely to occur on the same catalyst used in real Indusl.rlal applications. 

Kwong TC, et al. National academy of chnical biochemistry laboratory medicine practice guidelines recommendations for the use of laboratory tests to support poisoned patients who present to the emergency department. Clin Chem 2003 49 357-79. 

Cyanide poisoning does not cause production of cyanohe-moglobinemia or cyanosis. It does produce cytotoxic anoxia by poisoning cytochrome oxidase and other respiratory enzymes, thereby preventing utilization of O2 by tissues. Cyanide poisoning is detected by the characteristic odor of HCN gas (odor of bitter almonds) on the breath and by laboratory tests (absorption spectra, tests for CN-). 

At the same time, doctors and nurses from the Self Defense Force Central Hospital also suspected sarin poisoning and brought various documents and supplies to St. Luke s International Hospital. By the time most of the patients with cardiopulmonary or respiratory arrest had been resuscitated, results of laboratory tests revealed decreased plasma cholinesterase. Based on the various medical data, clinical and test findings, sarin poisoning was diagnosed with relative ease. 

Ironically, although they can destroy plants in a few hours, paraquat and diquat are not quick-acting mammalian poisons and can take several days or even weeks to kill a human. However, the use of a substance for murder or suicide tends to depend more on its availability than to its speed as a killing agent. Hence, both paraquat and diquat have been widely used by those with suicidal intent. The lingering, unpleasant nature of the death inflicted by these chemicals also makes them attractive options for those whose culture makes a "macho" form of suicide more socially acceptable. In addition, without proper laboratory tests, the s)unptoms of... 

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