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Liquid and lyophilized samples of Lachesis muta venom were stored at different temperatures and for different periods of time, and analyzed by polyacrylamide gel electrophoresis (PAGE) and immunoelectrophoresis. Only slight variations were evident when three pools of freeze-dried venom, that had been kept at -30 degrees C for several months were compared with fresh venom. These results suggest that L. muta venom is not altered drastically when stored under these conditions. Universidad de Costa Rica/[02-07-10-66]/UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)

Esta investigación fue financiada por la Vicerrectoría de Investigación de la Universidad de Costa Rica, Proyecto No 02-07 10-67 Venoms from adult and newborn Central American rattlesnakes (Crotalus durissus durissus) were compared for lethal, proteolytic, hemorrhagic, myonecrotic, edematigenous and in vitro hemolytic activities. Electrophoretic and immunoelectrophoretic patterns showed some differences between these venoms. Venom from newborn snakes was devoid of hemorrhagic and edematigenous activities, whereas the venom from adult specimens induced these effects. On the other hand, newborn snake venom showed higher lethality and indirect hemolytic activity, and lower proteolytic activity, than venom from adult specimens. Both types of venoms induced only slight myonecrosis in mice, as judged by histological observation. The ED50 of an antivenom, in terms of absolute weight neutralized per ml of serum, was lower for the newborn specimens venom than for adult's venom, however, for each venom the number of LD50 neutralized was similar. Universidad de Costa Rica, Vicerrectoría de Investigación UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)

The mode by which coral snake (Micrurus nigrocinctus) venom affects skeletal muscle was studied using a combined approach. The venom induced early functional and structural alterations in the plasma membrane of muscle cells, suggesting that sarcolemma is the primary site of action of this venom. This was shown by the presence of wedge-shaped ('delta') lesions at the periphery of the cells, as well as by focal disruptions in the continuity of plasma membrane as early as 1 5 min after envenomation. After this initial alteration the rest of the organelles were severely affected. Myofilaments were hypercontracted leaving, as a consequence, areas of overstretched myofibrils as well as empty spaces. Eventually, myofilaments formed dense, clumped masses in which the striated structure was totally lost. At 24 h, myofilaments were still disorganized but they presented a more hyaline and homogeneous appearance. As early as 1 5 and 30 min mitochondria were swollen; later, by 1, 3 and 24 h, they showed further alterations such as the presence of dense intracristal spaces and vesiculated cristae, as well as disruption in the integrity of their membranes. Sarcoplasmic reticulum was dilated and disorganized into many small vesicles randomly distributed throughout the cellular space. Moreover, the venom induced a rapid decrease in muscle levels of creatine and creatine-kinase (CK) and a calcium influx. Since the rates of efflux of creatine and CK were similar, it is suggested that the lesions produced in the membrane are large enough to allow the escape of these two molecules. As corroboration of the severe myotoxic effect, envenomated mice excreted reddish urine containing large quantities of myoglobin. Skeletal muscle cells are more susceptible to the action of the venom than erythrocytes, since coral snake venom induced only a mild direct haemolytic effect in vitro and haemolysis is not a significant effect in vivo. M. nigrocinctus venom induced a drastic increase in plasma levels of lactate dehydrogenase. Isozymes LDH-3, LDH-4, and LDH-5 increased markedly, suggesting that the systemic pathology of coral snake envenoming may be more complex than previously thought. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)

The ability of several batches of polyvalent antivenom to neutralize indirect hemolytic activity of Bothrops asper venom was studied using a sensitive plate test. All samples of antivenom tested effectively neutralized this activity. A highly significant correlation was observed between neutralization of indirect hemolysis and neutralization of lethal activity. This simple and sensitive in vitro test could be used to monitor antibody levels in horses immunized to produce polyvalent antivenom. UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)

The neutralizing capacity of the blood serum of the non-venomous snake Clelia clelia against the hemorrhagic, edematous and myonecrotic effects of Bothrops asper venom in white mice was tested using in vitro preincubation experiments. Untreated serum neutralized to a different extent all local effects evaluated, but showed toxicity to mice, evidenced by edema and myonecrosis. Serum heated at 56°C for 30 min lost its toxic properties but also its neutralizing capacity against hemorrhagic and edematous effects of the venom. The myonecrotic effect was neutralized by large quantities of heated serum. The serum of C. clelia formed a single precipitation arc in immunoelectrophoretic slides against B. asper venom, corresponding to the slow anodic proteins of the serum. Universidad de Costa Rica//UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)

Se presenta la revisión de varias investigaciones sobre la patogénesis y neutralización de los efectos locales inducidos por el veneno de la serpiente terciopelo. El cuadro local está constituido por mionecrosis, hemorragia y un proceso inflamatorio, además de otras alteraciones vasculares como angionecrosis y trombosis. La necrosis de fibras musculares se desarrolla después de inocular el veneno. La experimentación se realizó en ratones, los que muestran una alta proporción de fibras necróticas tres horas después del envenenamiento. El efecto hemorrágico es de aparición inmediata, así como el cuadro inflamatorio local y las alteraciones vasculares. Los sueros antiofídicos antivalentes producidos en Costa Rica contienen anticuerpos capaces de neutralizar los efectos locales siempre y cuando el suero y el veneno se incuben antes de la inoculación. Sin embargo, cuando el veneno se administra antes que el suero, los efectos locales solo son neutralizados parcialmente. Esto sugiere que el rápido desencadenamiento de dichos efectos al entrar el veneno a los tejidos, dificulta su neutralización por los sueros antiofídicos. El suero sanguíneo de la serpiente "zopilota" es capaz de neutralizar los efectos locales de la serpiente "terciopelo", cuando se incuba con el veneno antes de la inoculación. No obstante, este suero es tóxico para el ratón por lo que su potencial uso en el tratamiento de las mordeduras de serpientes no es posible en este momento. Universidad de Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)

En el presente trabajo se describe el programa para el cálculo de la actividad hemolítica del complemento sérico, y se muestran los resultados de un estudio comparativo entre el método gráfico manual y el método matemático empleando dicho programa. Universidad de Costa Rica//UCR/Costa Rica UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias de la Salud::Instituto Clodomiro Picado (ICP)