Antivenom Administration After Rattlesnake Envenoming in Arizona Does Not Directly Diminish Pain.

The onset, progression, and severity of pain following rattlesnake envenomation are highly variable between patients. Pain can be severe and persistent, seemingly refractory to opioid analgesics. The ability of antivenom to directly relieve pain has not been well studied.

Phosphate-Buffered Saline and Dimethyl Sulfoxide Enhance the Antivenom Action of Ruthenium Chloride against Venom in Human Plasma-A Preliminary Report.

Ruthenium chloride (RuCl) is widely utilized for synthesis and catalysis of numerous compounds in academia and industry and is utilized as a key molecule in a variety of compounds with medical applications. Interestingly, RuCl has been demonstrated to modulate human plasmatic coagulation and serves as a constituent of a compounded inorganic antivenom that neutralizes the coagulopathic effects of snake venom in vitro and in vivo. Using thrombelastography, this investigation sought to determine if RuCl inhibition of the fibrinogenolytic effects of venom could be modulated by vehicle composition in human plasma.

Ruthenium Antivenom Inhibits the Defibrinogenating Activity of Venom in Rabbits.

Eastern Diamondback Rattlesnake () envenomation is a medical emergency encountered in the Southeastern United States. The venom contains a snake venom thrombin-like enzyme (SVTLE) that is defibrinogenating, causing coagulopathy without effects on platelets in humans. This investigation utilized thrombelastographic methods to document this coagulopathy kinetically on the molecular level in a rabbit model of envenomation via the analyses of whole blood samples without and with platelet inhibition.

Ruthenium-based antivenom attenuates Crotalus atrox venom mediated coagulopathy in rabbits.

Background: The Western diamondback rattlesnake ( Crotalus atrox ) is a medically important venomous snake in the Southwestern United States, injuring humans, and their companion animals. The goals of this investigation were to utilize a rabbit model of subcutaneous envenomation to assess Crotalus atrox venom coagulopathy and determine the efficacy of a ruthenium-containing antivenom (RA) in attenuating it.

Methods: Sedated New Zealand White rabbits had viscoelastic measurements of whole blood coagulation kinetics obtained from ear artery samples.

Novel Toxicodynamic Model of Subcutaneous Envenomation to Characterize Snake Venom Coagulopathies and Assess the Efficacy of Site-Directed Inorganic Antivenoms.

Venomous snake bite adversely affects millions of people yearly, but few animal models allow for the determination of toxicodynamic timelines with hemotoxic venoms to characterize the onset and severity of coagulopathy or assess novel, site-directed antivenom strategies. Thus, the goals of this investigation were to create a rabbit model of subcutaneous envenomation to assess venom toxicodynamics and efficacy of ruthenium-based antivenom administration. New Zealand White rabbits were sedated with midazolam via the ear vein and had viscoelastic measurements of whole blood and/or plasmatic coagulation kinetics obtained from ear artery samples.

The Gilded Clot: Review of Metal-Modulated Platelet Activation, Coagulation, and Fibrinolysis.

The processes of blood coagulation and fibrinolysis that in part maintain the physical integrity of the circulatory system and fluidity of its contents are complex as they are critical for life. While the roles played by cellular components and circulating proteins in coagulation and fibrinolysis are widely acknowledged, the impact of metals on these processes is at best underappreciated. In this narrative review we identify twenty-five metals that can modulate the activity of platelets, plasmatic coagulation, and fibrinolysis as determined by in vitro and in vivo investigations involving several species besides human beings.

A Case Report of Severe Factor XI Deficiency during Cardiac Surgery: Less Can Be More.

Severe congenital Factor XI (FXI) deficiency (<20% normal activity) can be associated with significant bleeding disorders, and there has been great concern for severe bleeding following cardiac surgery requiring cardiopulmonary bypass (CPB) in this patient population. Over the past four decades remarkably different approaches to this problem have been taken, including the administration of blood volumes of fresh frozen plasma, administration of activated recombinant Factor VII, and diminutive administration of heparin. We describe a case wherein the patient was assessed in the perioperative period with a point-of-care, viscoelastic hemostasis device (ROTEM), with changes in the intrinsic/Factor XII-dependent coagulation pathway determined before, during, and after CPB.

Review of the Mechanisms of Snake Venom Induced Pain: It's All about Location, Location, Location.

Pain-acute, chronic and debilitating-is the most feared neurotoxicity resulting from a survivable venomous snake bite. The purpose of this review is to present in a novel paradigm what we know about the molecular mechanisms responsible for pain after envenomation. Progressing from known pain modulating peptides and enzymes, to tissue level interactions with venom resulting in pain, to organ system level pain syndromes, to geographical level distribution of pain syndromes, the present work demonstrates that understanding the mechanisms responsible for pain is dependent on "location, location, location".

Thrombocytosis and neutrophilia associated with oxygenator failure and protamine reaction after cardiopulmonary bypass: a case report and literature review.

Thrombocytosis has been feared as a source of thrombotic complications during the conduct of cardiopulmonary bypass (CPB) for patients undergoing cardiac procedures. We present a patient urgently requiring repair/replacement of three heart valves that had preexisting myelofibrosis with thrombocytosis (platelet count of 800,000 per µl) and neutrophilia (40,000 per µl). Despite achieving an activated clotting time > 500 s with heparin and antithrombin concentrate administration prior to CPB, the pump oxygenator and reservoir demonstrated significant clot just prior to restoration of the patient's circulation.

Modulation of Diverse Procoagulant Venom Activities by Combinations of Platinoid Compounds.

Procoagulant snake venoms have been inhibited by the ruthenium containing compounds CORM-2 and RuCl separately, presumably by interacting with critical histidine or other sulfur-containing amino acids on key venom enzymes. However, combinations of these and other platinoid containing compounds could potentially increase, decrease or not affect the procoagulant enzyme function of venom. Thus, the purpose of this investigation was to determine if formulations of platinoid compounds could inhibit venom procoagulant activity and if the formulated compounds interacted to enhance inhibition.

Platinoid effects on human plasmatic coagulation kinetics: a viscoelastic analysis.

In recent years a variety of metals (cadmium, chromium, copper, iron) have been demonstrated to modulate coagulation in vitro and in vivo. One group of metals, the platinoids, have not been assessed, and such investigation is justified given the thromboembolic phenomena associated with platinum-based chemotherapy. Thus, the goal of the present investigation was to assess the effects of carboplatin, cisplatin (platinum compounds), NAMI-A, and ruthenium chloride (ruthenium compounds) on human plasmatic coagulation.

Ruthenium, Not Carbon Monoxide, Inhibits the Procoagulant Activity of , , and Venoms.

The demonstration that carbon monoxide releasing molecules (CORMs) affect experimental systems by the release of carbon monoxide, and not via the interaction of the inactivated CORM, has been an accepted paradigm for decades. However, it has recently been documented that a radical intermediate formed during carbon monoxide release from ruthenium (Ru)-based CORM (CORM-2) interacts with histidine and can inactivate bee phospholipase A activity. Using a thrombelastographic based paradigm to assess procoagulant activity in human plasma, this study tested the hypothesis that a Ru-based radical and not carbon monoxide was responsible for CORM-2 mediated inhibition of , and species snake venoms.

Mechanisms Responsible for the Anticoagulant Properties of Neurotoxic Venoms: A Viscoelastic Analysis.

Using thrombelastography to gain mechanistic insights, recent investigations have identified enzymes and compounds in and species' neurotoxic venoms that are anticoagulant in nature. The neurotoxic venoms of the four extant species of (the Black and green mambas) were noted to be anticoagulant in nature in human blood, but the mechanisms underlying these observations have never been explored. The venom proteomes of these venoms are unique, primarily composed of three finger toxins (3-FTx), Kunitz-type serine protease inhibitors (Kunitz-type SPI) and <7% metalloproteinases.

The anticoagulant effect of Apis mellifera phospholipase A is inhibited by CORM-2 via a carbon monoxide-independent mechanism.

Bee venom phospholipase A (PLA) has potential for significant morbidity. Ruthenium (Ru)-based carbon monoxide releasing molecules (CORM) inhibit snake venoms that are anticoagulant and contain PLA. In addition to modulating heme-bearing proteins with carbon monoxide, these CORM generate reactive Ru species that form adducts with histamine residues resulting in changes in protein function.

Characterization of L-amino Acid Oxidase Derived from Venom: Procoagulant and Anticoagulant Activities.

Snake venom enzymes of the L-amino acid oxidase (LAAO) class are responsible for tissue hemorrhage, edema, and derangement of platelet function. However, what role, if any, these flavoenzymes play in altering plasmatic coagulation have not been well defined. Using coagulation kinetomic analyses (thrombelastograph-based), it was determined that the LAAO derived from venom displayed a procoagulant activity associated with weak clot strength (no factor XIII activation) similar to thrombin-like enzymes.

Anticoagulant activity of krait, coral snake, and cobra neurotoxic venoms with diverse proteomes are inhibited by carbon monoxide.

Background: A phenomena of interest is the in vitro anticoagulant effects of neurotoxins found in elapid venoms that kill by paralysis. These enzymes include phospholipase A2 (PLA2), and it has recently been demonstrated that carbon monoxide inhibits the PLA2-dependent neurotoxin contained in Mojave rattlesnake type A venom. The purpose of this investigation was to assess if the anticoagulant activity of elapid venoms containing PLA2 and/or three finger toxins could be inhibited by carbon monoxide.

Carbon monoxide inhibits the anticoagulant activity of Mojave rattlesnake venoms type A and B.

The Mojave rattlesnake is a unique species of pit viper that expresses either a highly potent phospholipase A (PLA)-dependent neurotoxin containing venom nearly devoid of fibrinogenolytic metalloproteinases (venom type A) or a hemotoxic venom with a high percentage of metalloproteinases and PLA without any neurotoxin present (venom type B) depending on its geographical location in the Southwestern United States and Mexico. Given that PLA have been demonstrated to affect coagulation, it was hypothesized that the anticoagulant effects of both type A and B venoms could be assessed by thrombelastography, and determination made if these venoms were heme modulated. Both venom types were exposed to carbon monoxide releasing molecule-2 or its inactivated molecule (0 or 100 µM) in isolation and then placed in human plasma with consequent coagulation kinetics assessed by thrombelastography.

Carbon monoxide releasing molecule enhances coagulation and decreases fibrinolysis in canine plasma exposed to Crotalus viridis venom in vitro and in vivo.

Carbon monoxide releasing molecule-2 (CORM-2), an emerging therapeutic in human medicine, enhances plasmatic coagulation and attenuates fibrinolysis in vitro in human, rabbit and horse plasma and ameliorates hypocoagulation and hyperfibrinolysis secondary to venom exposure in human plasma in vitro. Fibrinogenases in rattlesnake venom cause decreased clot strength, and in the presence of tissue plasminogen activator (tPA) in vitro, a markedly increased rate of clot lysis. CO interacts with a haem group on fibrinogen, changing its configuration so that the fibrin clot is strengthened and more resistant to fibrinolysis.

The kallikrein-like activity of Heloderma venom is inhibited by carbon monoxide.

Lizards in the genus Heloderma are the most ancient venomous reptiles, with a traceable lineage nearly 100 million years old. The proteome of the venom of three of the remaining species (Heloderma suspectum, H. exasperatum, H.

De Novo Assessment and Review of Pan-American Pit Viper Anticoagulant and Procoagulant Venom Activities via Kinetomic Analyses.

Snakebite with hemotoxic venom continues to be a major source of morbidity and mortality worldwide. Our laboratory has characterized the coagulopathy that occurs in vitro in human plasma via specialized thrombelastographic methods to determine if venoms are predominantly anticoagulant or procoagulant in nature. Further, the exposure of venoms to carbon monoxide (CO) or -phenylhydroxylamine (PHA) modulate putative heme groups attached to key enzymes has also provided mechanistic insight into the multiple different activities contained in one venom.

Carbon monoxide inhibits the anticoagulant activity of phospholipase A purified from Crotalus adamanteus venom.

Snake venom contains a myriad of classes of enzyme which have been investigated for medicinal and toxinological purposes, including phospholipase A (PLA), which is responsible for anticoagulant, myotoxic and neurotoxic effects. Given the importance of PLA, the purposes of the present investigation were to characterize the coagulation kinetic behavior of a PLA purified from Crotalus adamanteus venom (Ca-PLA) in human plasma with thrombelastography and determine if carbon monoxide could inhibit its activity. Coagulation kinetics were determined in human plasma with a range of Ca-PLA activity (0-2 U/ml) via thrombelastography.

Differential heme-mediated modulation of Deinagkistrodon, Dispholidus, Protobothrops and Pseudonaja hemotoxic venom activity in human plasma.

Envenomation by vipers with hemotoxic enzymes continues to be a worldwide source of morbidity and mortality. The present work examined the effects of exposure of venom enzymes to carbon monoxide and O-phenylhydroxylamine, agents that modulate the biometal heme, by forming carboxyheme and metheme, respectively. Four venoms obtained from medically important, diverse snake venom found in Africa, Asia and Australia were analyzed.