Herbicides and Fungicides Flashcards
The carcinogenicity observed with some phenoxy herbicides is though to be due to contamination with what compound?
Dioxin (TCDD)
Toxic effects associated with phenoxy herbicide poisoning are due to:
Uncoupling of oxidative phosphorylation in mitochondria
The caustic nature of these agents
The dog is the most sensitive species to toxicities associated with phenoxy herbicide poisoning exposure. What potential mechanism explains this increased sensitivity when compared to other species?
Decreased renal elimination leading to a longer half-life and greater exposure.
Paraquat toxicity differs from diquat toxicity primarily due to:
Selective accumulation of paraquat in the lungs.
Diquat and paraquat are both thought to exert a toxic effect thru the generation of what?
Reactive oxygen species
Glyphosate toxicity
Caused by irritating effects of anionic surfactants included in formulations
Glyphosate Tx
Decontamination and supportive care
Does glyphosate undergo metabolism?
Minimal
Which herbicide has a low tox but is often mixed with other herbicides and is known to be a peroxisome proliferator in rodents?
Dicamba
Major issue associated with triazine and triazole tox:
Grazing of livestock on recently treated pasture
Tox characteristic of Captan (chloroalkylthiodicarboximides)
Fungicide
Low protein diet can increase sensitivity to toxicosis
Toxicity of 2-methyoxymethylmercury chloride (metallic fungicides)
Immunotoxic and Neurotoxic
Characteristic of Thiram (carbamic acid derivatives)
Smells like rotten eggs
Used as an animal repellant
Tox signs of pentachlorophenol (halogenated substituted monocyclic aromatics)
Excitation and seiure caused with high acute doses
What are the differences between paraquat and diquat with regards to MOA?
What is the common name of glyphosate?
Round Up
CS of phenoxy herbicide toxicosis
Myotonia
Ataxia
Posterior weakness
Vomiting
Bloody diarrhea
Metabolic acidosis
Which is more toxic: paraquat or diquat?
Paraquat
Paraquat route of exposure
Ingestion of commercial paraquat concentrates before use or prior to soil binding (once bound in soil = biologically unavailable)
Paraquat Poisoning CS
Acute:
1. Caustic action leading to pain in the GI (vomiting/aphagia)
2. Renal failure + hepatocellular necrosis
3. Delayed dev of pulmonary fibrosis (poor prognosis)
Chronic low dose
1. Hyperplasia of type II alveolar epithelial cells
2. Healing via fibrosis (poor O2 sat)
Paraquat Treatment
GI decontamination
Increase elimination
Supportive care
Guarded prognosis
Diquat CS
Anorexia
GI distension
Renal impairment
CNS excitement
Convulsions
How are animals exposed to diquat?
Must consume directly rather than from sprayed vegetation. Good prognosis
Gyphosate MOA
Unknown
