RESUMEN
People bitten by Alpine vipers are usually treated with antivenom antisera to prevent the noxious consequences caused by the injected venom. However, this treatment suffers from a number of drawbacks and additional therapies are necessary. The venoms of Vipera ammodytes and of Vipera aspis are neurotoxic and cause muscle paralysis by inducing neurodegeneration of motor axon terminals because they contain a presynaptic acting sPLA2 neurotoxin. We have recently found that any type of damage to motor axons is followed by the expression and activation of the intercellular signaling axis consisting of the CXCR4 receptor present on the membrane of the axon stump and of its ligand, the chemokine CXCL12 released by activated terminal Schwann cells. We show here that also V. ammodytes and V. aspis venoms cause the expression of the CXCL12-CXCR4 axis. We also show that a small molecule agonist of CXCR4, dubbed NUCC-390, induces a rapid regeneration of the motor axon terminal with functional recovery of the neuromuscular junction. These findings qualify NUCC-390 as a promising novel therapeutics capable of improving the recovery from the paralysis caused by the snakebite of the two neurotoxic Alpine vipers.
Asunto(s)
Indazoles , Receptores CXCR4 , Venenos de Víboras , Viperidae , Animales , Parálisis/inducido químicamente , Receptores CXCR4/agonistas , Venenos de Víboras/antagonistas & inhibidores , Venenos de Víboras/toxicidad , Vipera/metabolismo , Viperidae/metabolismo , Ratones , Indazoles/farmacología , Indazoles/uso terapéutico , Piperidinas/farmacología , Piperidinas/uso terapéutico , Piridinas/farmacología , Piridinas/uso terapéutico , Mordeduras de Serpientes/tratamiento farmacológicoRESUMEN
In South America there are three snake genera with predominantly neurotoxic venoms: Crotalus, Micrurus and Hydrophis, which include nine species/subspecies, 97 species and a single marine species, respectively. Although accidents with neurotoxic venoms are less frequent than those with anticoagulant, cytotoxic or necrotic venoms (e.g. from Bothrops), they are of major public health importance. Venoms from genus Crotalus have been extensively studied, while data on the venoms from the other two genera are very limited, especially for Hydrophis. The venoms of North and South American Crotalus species show biochemical and physiopathological differences. The former species cause bothrops-like envenomation symptoms, while the latter mainly have neurotoxic and myotoxic effects, leading to respiratory paralysis and, occasionally, renal failure by myoglobinuria and death, often with no local lesions. Micrurus and Hydrophis also cause neurotoxic envenomations. Many studies have isolated, identified and characterized new enzymes and toxins, thus expanding the knowledge of snake venom composition. The present review summarizes the currently available information on neurotoxic venoms from South American snakes, with a focus on protein composition and toxicological properties. It also includes some comments concerning potential medical applications of elapid and crotalic toxins.
Asunto(s)
Bothrops , Crotalus , Animales , Elapidae , Venenos de Serpiente/toxicidad , América del SurRESUMEN
There are multiple reports of recreational snake envenomation describing psychotropic effects in absence of any adverse effects. This is in contradiction with known effects of snake venom. We report a case of a young male who subjected himself to repeated envenomation by a snake purported to be 'Indian Cobra' and experienced a 'high'. However, a direct identification of snake revealed it was a benign 'Rat snake'. We attempt to explain the reported psychological effects as a result of high expectation of rewarding experience, strong suggestion, personality traits and most importantly the dangerous nature of willfully receiving snakebites.
Asunto(s)
Trastorno por Déficit de Atención con Hiperactividad/psicología , Parálisis de Bell/psicología , Mordeduras de Serpientes/psicología , Trastornos Relacionados con Sustancias/psicología , Adulto , Animales , Colubridae , Humanos , India , Masculino , Venenos de Serpiente , Adulto JovenRESUMEN
Six of the 15 species of venomous snakes found in Taiwan are responsible for most of the clinically significant envenomations in the country. These species are: Trimeresurus mucrosquamatus, Trimeresurus stejnegeri, Naja atra, Bungarus multicinctus, Deinagkistrodon acutus and Daboia russelii siamensis, which together can be subdivided into three groups based on their venom effects. Primary treatment consists of rapid administration of appropriate antivenoms. The present study aimed to identify a proper dose of antivenom for each snake group as well as to describe hemorrhagic, neurotoxic, and mixed effects of their venoms. A retrospective chart review identified 72 snakebite cases referred to an emergency department. Data on epidemiology, examination findings, snake identification, treatment, antivenom dose and complications were collected. After excluding 14 patients, data from 58 victims were analyzed. Most studied cases were male (86 percent). Significantly higher doses of antivenom were administered against neurotoxic envenomations (mean dose: three vials) compared with the other two (p < 0.05). Moreover, patients affected by neurotoxic bites were more likely to develop blurred vision and other complications (p < 0.05). Multivariate logistic regression analysis indicated that neurotoxic envenomation was a risk factor for complications (OR: 8.84, 95 percent CI: 1.06-73.73). Neurotoxic envenomations and complication occurrence were positively correlated with antivenom dosage. In conclusion, patients affected by neurotoxic envenomations received higher doses of antivenom than others whereas incidence of complications was associated with higher antivenom doses.