Hydrolysis catalyzed by general esterases
(GEs) is the most efficient
route for hydrolyzation of pyrethroid insecticides. Organophosphate
(OP) and carbamate (CB) insecticides are known to inhibit GEs in addition
to acetylcholinesterase (AChE), which is their main target. We hypothesize
that synergies can be induced by OPs and CBs when mixed with pyrethroids,
due to their inhibition of GE-dependent detoxification of pyrethroids.
To test this hypothesis, we conducted mixture toxicity experiments
with Daphnia magna using α-cypermethrin
(α-cyp) in combination with the noninsecticidal OP tetraisopropyl
pyrophosphoramide (iso-OMPA) and five AChE inhibitors
diazinon, chlorpyrifos, chlorfenviphos, parathion, and aldicarb. In
addition, the in vivo GE activity inhibition was
measured for all compounds. Up to 10-fold synergy was found between
α-cyp and iso-OMPA, and the degree of synergy
correlated linearly with the inhibition of the GE activity. No synergy,
however, was found in any of the insecticide mixtures nor was the
GE activity inhibited within the nonlethal concentration range tested.
It was concluded that the effect of the insecticides on AChE occurred
at lower concentrations than their effect on GEs, making the daphnids
become immobilized before any synergistic effects on mortality could
be observed. The implications of the findings are discussed from a
risk assessment perspective.
Delirium is a frequent cause of decompensation in the elderly, especially with higher prevalence in highly dependent patients, in advanced ages and senile dementia. It is important to always look for the principal cause before treating only the symptom. This case describes a 79-year-old woman with an episode of agitation and disorientation lasting several days, underestimated by its mild nature, but which ends up being a thalamic hemorrhagic stroke. Hemorrhagic stroke is a less common pathology than ischemic stroke but with higher morbidity and mortality. Specifically focused on the thalamus produces behavioral and sensory alterations that can be confused with multiple pathologies. Early identification and approach influence recovery and the sequelae that are being worked with different physiotherapeutic therapies.
Visual hallucinations and capgras delirium in a patient with right occipito-temporal ischemic stroke alberto ibáñez navarro, José antonio oliván usieto, iván José salas garc ía, newton arza candia, teddy weimar cordova irusta
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