Bryan Ballantyne

Clinical and experimental toxicology of organophosphates and carbamates

Basic science neurotoxicity specific organ and long-term toxicology environmental aspects exposure patterns protection and monitoring clinical toxicology by geographical regions clinical and therapeutic aspects.

Pesticide toxicology and international regulation

Preface.List of Contributors.Frequently Used Abbreviations.Toxicity Classifications and Hazard Ratings.1. Pesticides: An Overview of Fundamentals (Bryan Ballantyne & Timothy Marrs).PART I: INSECTICIDES.2. Toxicology of Organochlorine Insecticides (Andrew G. Smith).3. Anticholinesterase Insecticides (Charles M. Thompson and Rudy J. Richardson ).4. Toxicology of Pyrethrins and Synthetic Pyrethroids (David E. Ray).5. Toxicology of miscellaneous insecticides (Roland Solecki).PART II: FUNGICIDES, HERBICIDESM AND GROWTH REGULATORS.6. Toxicology of Fungicides (Bryan Ballantyne).7. Toxicology of Herbicides (Timothy C. Marrs).PART III: SPECIAL TYPES OF PESTICIDE.8. Microbial Pesticides (Ian C. Dewhurst).9. Biocides (Bryan Ballantyne and Susan L. Jordan).PART IV: RESIDUES.10. Variability of Residues in Unprocessed Food Items and its Impact on Consumer Risk Assessment (Caroline A. Harris and Alan R. C. Hill).PART V: HUMAN ASPECTS.11. Occupational Aspects of Pesticide Toxicity in Humans (Angelo Moretto).12. Treatment of Pesticide Poisoning (Gregory P. Wedin and Blaine E. Benson).PART VI: REGULATION.13. Regulation of Pesticides and Biocides in the European Union (Deborah J. Hussey and Graham M. Bell).14. Regulation in NAFTA (Cheryl E. A. Chaffey and Virginia A. Dobozy).15. The Regulatory System in Japan (Kannosuke Fujimori).Index.

Occupational Toxicology and Occupational Hygiene Aspects of Organophosphate and Carbamate Anticholinesterases with Particular Reference to Pesticides

Publisher Summary Organophosphates (OPs) and carbamates (CMs) may have a wide spectrum of potential occupational toxicity, and hence, the necessary protective and precautionary measures dictated by occupational hygiene considerations may be extensive and vary for differing chemical groups. The most geographically extensive and quantitatively greatest application of OPs and CMs is as pesticides used in agriculture, horticulture, public health protection, and domestically. OP and CM anticholinesterases (anti-ChEs) have a wide spectrum of applications that includes pesticides in agriculture and horticulture, insecticides in domestic and public health applications, use in general commerce, use in therapeutic medicine, and as chemical warfare and terrorist agents. During normal civilian use, and when handled correctly with the appropriate recommended protective and precautionary measures, they can be used safely. However, because of their widespread and sometimes uncontrolled usage, there is a potential for misuse. Also, because of the high biological activity of many OPs and CMs, the likelihood of adverse effects occurring from accidental, and sometimes deliberate, exposure is high. Although the principal mechanism of action that underlies the practical use of OPs and CMs, namely inhibition of the cholinesterase group of enzymes, is also responsible for some of their known human toxicity, because of the wide range of chemical structures involved, the potential for numerous and differing toxic effects that are mediated by other mechanisms also exists (e.g., inflammation, immunotoxicity, myopathy, genetic toxicity, oncogenicity, and developmental and reproductive toxicity).

Local and Systemic Ophthalmic Pharmacology and Toxicology of Organophosphate and Carbamate Anticholinesterases

Publisher Summary The chapter discusses the nature of toxic and pharmacological effects produced by anticholinesterases (anti-ChEs) as a result of their topical and/or systemic exposure to the eye, their investigation by laboratory in vitro and in vivo tests and by human clinical studies, and their practical and clinical implications. Human subjects may be exposed to carbamate (CM) or organophosphate (OP) anti-ChEs topically and/or systemically as a consequence of the wide range of their uses, which may result in exposures from deliberate, incidental, or accidental situations. The eye may be a local target organ for toxic and/or pharmacological effects of anti-ChEs that are applied by direct (topical) contact to the eye or that reach the eye from blood circulation. The various circumstances and conditions that determine the site and nature of effects are presented. ChEs, both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), are widely distributed in the eye. Many of the ocular pharmacological effects and some of the ocular toxic effects of anti-ChEs are attributable to their inhibitory effect on ChEs, and the resultant cholinergic response, but some toxic effects may be related to other properties of the molecule that are not a function of its anti-ChE potency. ChE inhibitors may produce varying types of corneal and ocular injury because of their chemical structure that is unrelated to anti-ChE activity, and for this reason, it is necessary to undertake eye irritation studies on the OP or CM pesticides and medical products, and their formulations.

Approaches to Defining and Evaluating the Inhalation Pharmacology and Toxicology Hazards of Anticholinesterases

Publisher Summary The extensive use of anticholinesterases (anti-ChEs) as pesticides and their application in the form of dusts, land-based sprays, and by aerial spraying means that anti-ChE pesticide exposures by inhalation of the vapor and/or aerosols are frequent. Inhalation studies are designed to determine the nature, onset, and duration of adverse effects and hazards from acute, short-term repeated and long-term repeated respiratory exposure; factors influencing the development of effects; and the efficacy of antidotal treatment. They are also designed to aid in the development of protective and precautionary measures, including recommendations on appropriate airborne concentrations to ensure safe working conditions. The development of pharmacological and potential short- and long-term toxicological effects from exposure to organophosphate (OP) and carbamate (CM) anti-ChEs by inhalation depends on various factors, of which the most important are the physicochemical properties of anti-ChE, whether exposure is to undiluted material or a formulation, and whether the material is physically and intentionally dispersed in the atmosphere for in-use application. Depending on the nature and required use of the material and its formulation, exposure by inhalation may be to vapor, liquid aerosol, or dust. The effects of inhaled anti-ChEs may, for descriptive purposes, be considered as local pharmacological effects on tissues within the respiratory tract, local toxicological effects on the respiratory tract, and systemic pharmacological and toxic effects that occur following absorption of anti-ChE into the systemic circulation. The nature of toxic effects also depends on whether exposure is by a single (acute) exposure or by repeated exposures.