Animals, lethal doses

When neither human data nor animal LC data were sufficient, NIOSH considered animal lethal dose (LD) data. NIOSH used the LD data to estimate the equivalent total dose to a 70 kg worker. The 30 min LC was estimated by dividing by 10 m, even though a worker breathing at a rate of 501min for 30 min would inhale 1.5 m of air. NIOSH determined a preliminary IDLH by dividing this estimated LC value by a factor of 10. 

Animal Lethal Dose of Ingested Castor Seed (g/kg) Lethal Dose of Injected (i.m.) Ricin (p.g/kg) Lethal Dose of Injected (i.p. or i.v.) Ricin (pig/kg) Relative Resistance to Injected (s.c.) Ricin ... 

Animal Lethal dose species (g/kg LW) Alcaloid content (%) y-Coniceine (%) y-Coniceine doses (g/kgLW)... 

Animal cells do not have a cell wall and are, thus, highly susceptible to the effects of shear stress. Cells respond to hydrodynamic stress within minutes, altering their metabolism and the gene expression pattern (Nol-lert et al., 1991). Under sub-lethal levels of shear stress, there is initially an increase in passive transmembrane transport, simultaneously with damage to surface receptors. The plasma membrane is generally the main site for shear damage, and it may lose its capacity to mediate the transport of ions and molecules, so that the cell loses its viability. It has been demonstrated... 

Viruses are the 2nd most problematic pathogen, behind protozoa. As with protozoa, most waterborne viral diseases don t present a lethal hazard to a healthy adult. Waterborne pathogenic viruses range in size from 0.020-0.030 jtim, and are too small to be filtered out by a mechanical filter. All waterborne enteric viruses affecting humans occur solely in humans, thus animal waste doesn t present much of a viral threat. At the present viruses don t present a major hazard to people drinking surface water in the U.S., but this could change in a survival situation as the level of human sanitation is reduced. Viruses do tend to show up even in remote areas, so a case can be made for eliminating them now. 

Several other acute lethality studies of phosgene in rats have been reported. However, as is the case with the mice, these studies do not contain experimental details such as strain or gender, number of animals exposed, or analytical methodology. These studies are summarized in Table 1-7. 

N-methylscopolamine (Costa et al. 1982b Schwab et al. 1983). Animals made tolerant to disulfoton were resistant to the lethal or adverse effects of cholinergic agonists, such as carbachol (Brodeur and DuBois 1964 Costa et al. 1981 Schwab and Murphy 1981) and oxotremorine (Costa et al. 1982b McPhillips 1969a), which are not hydrolyzed by acetylcholinesterase. Tissues from animals tolerant to disulfoton such as the ilea (Foley and McPhillips 1973 McPhillips 1969b McPhillips and Dar 1967) and the atria (Perrine and McPhillips 1970 Schwab et al. 1983), were resistant to the effects of carbachol and/or oxotremorine. Because the uterus and vas deferens have a relatively sparse parasympathetic innervation compared to the ileum and do not receive a steady flow of impulses via this system, these tissues were not as subsensitive to carbachol as the ileum (Foley and McPhillips 1973). Thus, acetylcholine accumulation may be a prerequisite for tolerance development. 

Based on all the above observations, we concluded that peripheral effects on the heart predict the lethal dose for belladonnoids better than do their central effects. This was apparently the case in animals such as the mouse, for which the LD50 had been previously established by direct measurement. EA 3443 and EA 3580, both of which have greater relative central potency in man than BZ, also were found to have higher safety margins in the mouse (and other species). 

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