Agents of Concern

Examples of Chemical and Biological Threat Agents of Concern, 9 2-2 Toxicities of Lethal Gases, 9... 

The single most important statistical consideration in the design of bioassays in the past was based on the point of view that what was being observed and evaluated was a simple quantal response (cancer occurred or it didn t), and that a sufficient number of animals needed to be used to have reasonable expectations of detecting such an effect. Though the single fact of whether or not the simple incidence of neoplastic tumors is increased due to an agent of concern is of interest, a much more complex model must now be considered. The time-to-tumor, patterns of tumor incidence, effects on survival rate, and age of first tumor all must now be captured in a bioassay and included in an evaluation of the relevant risk to humans. 

Regulatory guidance for the conduct of clinical trials on vaccines is specific. Traditional phase I trials in normal volunteers are not conducted. Rather, all trials assess not only safety but also efficacy (or at least immunogenicity). Trials may well be challenge trials, that is, after immunization subjects are purposely challenged with exposure to the infective agent of concern. 

For all agents of concern in occupational toxicology (except therapeutics), the major route by which the general population is most frequently exposed is the percutaneous (dermal) route. Brown (1980) has previously reviewed background incidence data on pesticides, for example, that show such exposures to be common. Dermal (or topical) drugs are not as common, but are certainly numerous. 

Note Typical agents of concern are amines, chlorides, cyanide, fluorides, and napthenic acid. 

E. Reduced peripheral vascular resistance occurs with most halogenated hydrocarbons, and reflex tachycardia may be a concern. Halothane may be the clearest exception, since there appears to be a balance between relaxation and constrictor influences in various vascular beds with this agent so that total peripheral resistance changes very little. Halothane is the agent of concern when sensitization of the myocardium to catecholamine-induced arrhythmias may be important, such as during incidences of hypercapnia. Sevoflurane does not directly influence sympathetic function. However, reflex tachycardia can occur. Reflex sympathetic... 

NOTE Typical agents of concern are hydrogen sulfide, amines, chlorides, bromides, iodides, cyanides, fluorides, naphthenic acid and polythionic acid. Other agents affecting elastomer selection include ketones, ethylene oxide, sodium hydroxide, methanol, benzene and solvents. 

There are a number of aspects that must be taken into account in accurate estimation of exposure. Quantification of the magnitude and timing of personal exposures to agents of concern requires the identification of sources and media of concern, key exposure microenvironments, and routes and pathways of exposure that contribute most to an individual s exposure. Unfortunately, the information base on which to estimate emissions, concentrations, exposures and doses associated with each of these steps is sometimes completely lacking, frequently incomplete, not representative or otherwise uncertain. Given... 

Infection control issues raised by these biological agents of concern raise serious threats to health care professionals, including clinical and laboratory personnel who may encounter patients or clinical specimens suspected of harboring highly lethal bacteria or viruses. 

Describe the CDC system for the categorization of biological agents of concern, with particular attention to Category A agents. 

Nurses need to be able to recognize and treat exposures to the chemical agents of concern. 

Centers for Disease Control and Prevention (CDC). (2006a). Chemical agents of concern. Retrieved March 27, 2007 from http //www.bt.cdc.gov/Agent/AgentlistChem.asp... 

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