Acute lethality, comparative toxicity

Comparative Acute Lethal Inhalation Toxicity to Four Species of Pyrotechnically Generated CR Smoke with that of Smoke Resulting from the Combustion of the Burning Mix Alone... 

Marine toxins are not always acutely toxic. This may be particularly so for toxins which are used to deter competing occupants for living space since they often have comparatively slow actions on growth. With such toxins, the procedures for the evaluation of acutely lethal toxins cannot apply. However, interesting discoveries may be made by using the simplest of screen of alcoholic extracts for cytolytic actions as exemplified in Table I of Shier 109),... 

When comparing the available acute lethal toxicity information for cyanide compounds, it was concluded that, for oral exposure, the molar lethal toxicities of hydrogen cyanide, sodium cyanide, and potassium cyanide are similar. Rabbits appeared to be more susceptible to the lethal toxicity of these three compounds than rats (Ballantyne 1988). 

Death. Occupational mortality studies of pesticide workers exposed to heptachlor have not revealed an excess number of deaths in these cohorts compared to the general U.S. population. This may possibly be explained as a healthy worker effect. The ERA has described human case reports in which convulsions and death were reported following suicidal ingestion of technical-grade chlordane, which typically contains 6-30% heptachlor, but these effects cannot be attributed to heptachlor or heptachlor epoxide. There are no controlled, quantitative human data for any route of exposure. Acute lethality data were located for animals exposed via the oral and dermal routes. Both heptachlor and heptachlor epoxide may be considered very toxic via the oral route on the basis of acute animal data in rats and mice. Intermediate oral exposure to these compounds also caused up to 40% and 100% mortality in rats and mice, respectively. There appear to be differences in sensitivity in males and females in some species with the males being most sensitive. Heptachlor epoxide is more toxic than heptachlor. Heptachlor may be considered very toxic to extremely toxic via the dermal route on the basis of acute lethality data in rats and mice. The severity of acute effects may possibly depend upon the extent of formation of heptachlor epoxide and the species tested. 

In general, a greater proportion of aquatic organisms are exposed to sublethal concentrations of toxics compared to acutely lethal concentrations. There is general acceptance that chronic exposure of fish to sublethal levels of toxics makes them more prone to disease states. Although scientifically controversial, intuitively one can grasp how individual responses such as growth, reproduction rates, and survival probability, as a function of age, could relate to population level responses. 

The LD50 is a statistical estimate of the acute lethality of an agent administered to a specified sex, age, and strain of a species of animal. The value provides a measure of the relative toxicity of an unknown agent compared to other agents administered by... 

Table 6. Comparative acute lethal toxicity of aqueous solutions of hydrogen, sodium and potassium cyanides...

The comparative data on the acute lethality of the chlorinated dibenzo-p-dioxins and furans in laboratory animals are included in Table I. Evaluation of these data indicates that TCDD is the most toxic of this series. For the guinea pig, the single dose oral LD50 value is reported to be 0.6-2.0 yg/kg B.W., while in the hamster the single dose oral LD50 value is reported to be 1157-5051 yg/kg B.W. 

Organic cyanide compounds, or nitriles, have been implicated in numerous human fatalities and signs of poisoning — especially acetonitrile, acrylonitrile, acetone cyanohydrin, malonitrile, and succinonitrile. Nitriles hydrolyze to carboxylic acid and ammonia in either basic or acidic solutions. Mice (Mus sp.) given lethal doses of various nitriles had elevated cyanide concentrations in liver and brain the major acute toxicity of nitriles is CN release by liver processes (Willhite and Smith 1981). In general, alkylnitriles release CN much less readily than aryl alkylnitriles, and this may account for their comparatively low toxicity (Davis 1981). 

CA are classically injected as a bolus. Acute toxicity estimated by the lethal dose 50 % (LDjo) is a relevant parameter for comparing such molecules. 

Acute toxicity Acute dose that is lethal in approximately 50% of animals and the maximum tolerated dose. Usually two species, two routes, single dose. Compare with therapeutic dose. 

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