Anticoagulants exposure

One study conducted in Britain between 1983 and 1989 was of barn owls found dead in the field 10% of the sample of 145 birds contained anticoagulant rodenticide residues in their livers, and difenacoum and brodifacoum were prominent among them (Newton et al. 1990). In another study, barn owls were fed rats that had been dosed with flocoumafen. It was found that a substantial proportion of the rodenticide ingested by owls was eliminated in pellets (Eadsforth et al. 1991). The authors suggest that exposure of owls to rodenticides in the field may be monitored by analysis of pellets dropped at roosts or regular perching places. 

Thiagarajan, P. and Tait J.F., 1990, Binding of annexin V/placental anticoagulant protein 1 to platelets. Evidence for phosphatidylserine exposure in the procoagulant response of activated platelets. J. Biol. Chem., 265 17420-17423. 

Warfarin, a coumarin anticoagulant, is incorporated into commeal for use as a rat poison. Repeated exposure results in sufficient inhibition of prothrombin synthesis to cause fatal internal hemorrhage. 

The two major kinds of samples analyzed for xenobiotics exposure are blood and urine. Both of these sample types are analyzed for systemic xenobiotics, which are those that are transported in the body and metabolized in various tissues. Xenobiotic substances, their metabolites, and then-adducts are absorbed into the body and transported through it in the bloodstream. Therefore, blood is of unique importance as a sample for biological monitoring. Blood is not a simple sample to process, and subjects often object to the process of taking it. Upon collection, blood may be treated with an anticoagulant, usually a salt of ethylenediaminetetraacetic acid (EDTA), and processed for analysis as whole blood. It may also be allowed to clot and be centrifuged to remove solids the liquid remaining is blood serum. 

Uniform Adsorption by Uniform Mechanical Exposure. If an adsorbing film is introduced into the solution at a uniform rate, the strike effect can be made uniform. Autoradiographs such as Figure 4 show that this can be accomplished, or at least that much more uniform adsorption can be obtained by dipping than by exposure in sacks. Whether the heparin so adsorbed is the same in its equilibrium relations to solutions is yet to be determined, but it appears similar in anticoagulant effect. 

TABLE 15.3. Number of exposures to long-acting anticoagulant rodenticides and deaths reported by the American Association of Poison Control Centers - Toxic Exposure... 

Experimental studies in perfusion devices can also be performed with non-anticoagulated blood [52] or with blood anticoagulated with low molecular weight heparin [53]. In contrast with the studies with citrated blood, the latter experimental systems allow the generation of thrombin and fibrin deposition on the damaged vessel due the concurrence of several mechanisms exposure of tissue fector in the subendothelium [54], presence of plasma coagulation fectors [55] and the expression of a procoagulant surface on activated platelets. 

Repeated exposures over time can lead to prolonged anticoagulation and appears to require a lower total... 

No case reports of toxicity have been directly attributed to bromadiolone. However, based on its mechanism of action as an anticoagulant, it is expected that excessive human exposure of bromadiolone is likely to produce epistaxis, bleeding of gums, pallor, and sometimes petechial hemorrhage leading to hematomas around the joints and on the buttocks. 

The majority of the eye is filled with a viscous, clear substance known as vitreous humor. The vitreous humor is rarely directly altered by toxic exposure, but bleeding into the vitreous may be a secondary effect of a systemic toxin such as an anticoagulant. 

Analysis of Pb is routinely performed by either ICP-Qj, electrothermal atomic absorption spectrometry. EDTA anticoagulated blood is the specimen of choice for Pb analysis, because Pb is concentrated in the erythrocytes. Sodium heparin may also be used however, samples that are not analyzed within 48 hours are frequently clotted and must be rejected. Care must be taken when obtaining capillary blood. Surface contamination, insufficient collection volume, and inadequate mixing with EDTA result in frequent sample rejection. Urinalysis can also be performed urine quantification correlates with exposure. 

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