Initial toxicity

Facilities to submit initial toxic chemical release forms to USEPA and designated stale officials [Section 313(a)]... 

Aldrin, like chlordan, exhibits residual effectiveness under field conditions for somewhat less than 3 weeks. Even when aldrin is applied at the uneconomical and unnecessary rate of 5 pounds per acre, leafy material so treated exhibits only slight insect toxicity after 3 weeks. Aldrin, therefore, falls into that class of materials which exhibit pronounced initial toxicity but relatively short residual action. 

Sufficient quantity is synthesized to (a) perform initial toxicity studies, (b) do initial analytical work, and (c) do initial preformulation. 

Once past initial toxicity, phase I (clinical pharmacology) begins and there is a need for actual formulations (although the dose level may not yet be determined). 

These arguments are countered by the point that it is difficult to be sure that what we have called the initiating toxic damage was actually responsible for the production of tumors. It might still be the case that the neoplasms would have developed even in the absence of that toxicity. So we should not, so this argument goes, drop our concern until we are certain that cancers would not have occurred without prior toxicity. This is not easy it is tough to rule one way or the other on this issue without additional data. 

Aromatic and heterocyclic cleavage involves a hydrocarbon being separated from an oxygen atom, which functions to link it to another moiety of the molecule this process may lead to a decrease in the initial toxicity. The metabolic effects of microorganisms differ with the molecular configuration of the product, which affect aromatic or heterocyclic ring cleavage differently. 

Initial toxicity data on an uncharacterized agent usually are obtained by oral, intraperi-toneal, or dermal administration to laboratory animals. This provides an estimate of the lethal potency of the material. Observation of the animals after administration of the material often provides valuable information concerning the effects that may occur in humans. Autopsy of the animals will show the likely target organs in humans. 

Sulphonyl endoperoxides (76) 4 steps (NR) Molecular oxygen (TOCO) reaction 9.4 nM (NF54) 0.43 mgkg Initial toxicity studies for 76 reveal no observable toxicity in mice at doses up to 200 mgkg 111... 

It is valuable to reiterate here that the tropane alkaloid-producing plants are all regarded as very toxic, and that since the alkaloids are rapidly absorbed into the blood stream, even via the skin, first aid must be very prompt. Initial toxicity symptoms include skin flushing with raised body temperature, mouth dryness, dilated pupils, and blurred vision. 

The chemical agent is activated to form the initiating toxic agent. 

The initiating toxic agent is either detoxified or causes molecular changes in the cell. 

In the evaluation of the toxic characteristics of a gas, volatile chemical, aerosol, or particulate matter, determination of subchronic inhalation toxicity may be performed after initial toxicity information has been obtained via acute testing. It provides information on health hazards likely to arise from repeated exposure by the inhalation route over a limited period of time. Hazards of inhaled chemicals are influenced by the inherent toxicity and by physical factors such as volatility and particle size. The housing and feeding conditions, before and after exposure to environmental chemicals, should be planned according to the standard animal husbandry conditions described for acute oral toxicity study. 

In order to obtain deeper insight into such complex effects, the definition of the deactivation extent induced by sulfur adsorption can provide a lot of information about its action. The simplest technique to characterize a poison is to define its initial toxicity as the number of accessible metal atoms deactivated through adsorption of the first molecule of poison (74). 

Initial Toxicities of Different Sulfur Compounds for Maleic Acid Hydrogenation... 

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