On the other hand, the preclinical assessment of antivenoms against viperid venoms should include the analysis of the lethal, hemorrhagic, myotoxic, coagulant and defibrinogenating activities of venoms . toxicity) venoms, which result in completely different envenomings from a pathophysiological standpoint, and these venom phenotypes show no phylogenetic relationship . Furthermore, the getting of different evolutionary solutions within arboreal taxa for the same trophic purpose  (Number 1) strengthens the look at that phylogeny cannot be invoked as the sole criterion for varieties selection for antivenom production. Open in a separate window Open in a separate window Number 1 Highly divergent toxin compositions in phylogenetically-close snake taxa. Venom components of four varieties that inhabit Costa Rica were assigned to protein family members, and their abundances were estimated, by using the snake venomics analytical strategy. As demonstrated in the related pie charts summarizing Artesunate protein family abundances (%), the venom of is definitely dominated by metalloproteinases, whereas small peptides of the vasoactive type are predominant in the venom of venom contains Artesunate the highest proportion of phospholipases A2, while venom completely lacks metalloproteinases and presents a high percentage of an unusual phospholipase A2 recently characterized like a crotoxin-like complex, found for the first time inside a non-rattlesnake New World pit viper. In addition, a novel protein type for snake venoms (Kazal-type proteinase inhibitor-like) was found in and and checks, and the investigation of the immunological cross-reactivity of antivenoms against homologous and heterologous venoms. Knowledge within the paraspecificity of antivenoms isn’t just of applied importance to optimize the production strategy of a novel antivenom, but also for predicting the full medical range of existing antivenoms against homologous and heterologous venoms. To this end, a platform has U2AF1 been developed to explore the neutralizing ability and immunological cross-reactivity of antivenoms through a combination of methodologies that’ll be briefly discussed. 2. Biochemical and Toxinological Toolbox for the Preclinical Assessment of Antivenom Effectiveness The analysis of the ability of an antivenom to neutralize probably the most relevant harmful activities of the snake venoms for which it was designed is definitely a preclinical requisite before it can go into medical trials and is authorized for medical use. Simple experimental protocols have been developed to assess the ability of antivenoms to neutralize probably the most relevant harmful effects of snake venoms [22,33,34,35,36,37]. Probably the most widely-used protocol is based on the incubation of a fixed dose of venom and variable dilutions of antivenom, followed by the injection of aliquots of the mixtures in the related assay systems [22,33]. Another experimental platform, which is not regularly used, but which is relevant when screening antivenoms of variable pharmacokinetic profiles, is based on the injection of venom, followed by the administration of antivenom from the intravenous route. This approach does not involve the mixture of venom and antivenom before injection and, consequently, reproduces more closely the actual dynamics of therapy in the medical establishing. Lethality is the single most important effect to be tested when analyzing venom toxicity and its neutralization by antivenoms. For the lethality neutralization assay, challenging dose, which usually corresponds to 3 to 6 LD50s, depending Artesunate on the laboratory, is mixed with numerous dilutions of the antivenom, and the mixtures are incubated (generally for 30 min at 37 C). Control samples include venom incubated with saline answer instead of antivenom. The mixtures are then injected in mice, either by.