Resumo em Inglês:

The search for biological antitumor agents has been pursued for over half a century. Snake venom has been shown to possess a wide spectrum of biological activities. The objectives of the present review are to evaluate the existing controversies on this subject published in a number of papers and to propose probable explanations for the phenomena observed. We reported our results obtained in a study, in which we evaluated the action of the venoms of Crotalus durissus terrificus and Bothrops jararaca on Ehrlich ascites tumor cells. We noticed an important antitumor effect, mainly with Bothrops jararaca venom, as well as an increase in the functional activity of macrophages. We also observed an increase in the number of mononuclear and polymorphonuclear cells with Bothrops jararaca venom. Considering these findings, we postulate that both Bothrops jararaca and Crotalus durissus terrificus venoms can act directly on tumor cells. In addition, we propose an indirect mechanism, based on the stimulation of the inflammatory response, to inhibit tumor growth and to promote its rejection.

Resumo em Inglês:

Two scorpion species of medical importance occur in the state of São Paulo: the native brown scorpion Tityus bahiensis (Perty) and the highly toxic yellow scorpion Tityus serrulatus Lutz and Mello, which was brought into the state. The study of accident data of patients admitted to the Vital Brazil Hospital of the Butantan Institute from l982 to l993 revealed a gradual increase in stings by T. serrulatus in contrast to those by T. bahiensis with a variation from 5.2% to 29.7%. Also, an inventory of the scorpions sent to the Laboratory of Venomous Arthropods of the Butantan Institute over the same period showed an expressive growth in the number of T. serrulatus specimens in contrast to that of T. bahiensis. These data suggest a significative proliferation of T. serrulatus in the state of São Paulo over the past 12 years, and a probable interspecific competition between T. serrulatus and the endemic T. bahiensis. The analysis of scorpion accidents reported to the state of São Paulo Health Department (Secretaria de Estado da Saúde de São Paulo) corroborated the higher severity of T. serrulatus envenoming. The results pointed to the possibility of an increase in severe envenoming and deaths by scorpion stings in the state of São Paulo. Aiming to contribute to scorpion prevention and control programs, the present geographical distribution of both dangerous species was mapped, pointing to the areas of higher risk of scorpionism in the state.

Resumo em Inglês:

Phospholipase A2 (PLA2), a component of most snake venom toxins, cleaves 3-sn-phosphoglycerides releasing lysophosphatidyl-choline. The indirect quantitative assay method for PLA2 was standardized for specific antivenom titration in a fast and sensitive assay by the similarity with the hemolysis induced by PLA2 and by complement system in sheep erythrocytes. The curves obtained by plotting the degree of hemolysis against the doses of snake venom are concave to the abscissa axis following an equation similar to that previously described for the hemolysis induced by the C system. We observed that venoms of some Bothrops, Crotalus and Micrurus species contained around 1 x 10<img SRC="http:/img/fbpe/jvat/v2n2/image603.gif"> to 10<img SRC="http:/img/fbpe/jvat/v2n2/image604.gif"> Z/mg of venom, while the venom of Naja contained over one million Z/mg. Antibodies against PLA2 were titrated by incubating amounts of venom predetermined to give 1 to 5 Z with various dilutions of the antivenoms, and the remaining active PLA2 was determined in the hemolytic assay. We observed the following: a) the antivenoms contained specific antibodies against the PLA2 present in the corresponding venoms; b) cross-reactivity was not detected among PLA2 epitopes from venoms and nonspecific antivenoms; and c) the assay quantitatively performed determined the specific antibodies directed to epitopes on the molecule of PLA2. The method described in this paper is highly specific, sensitive and reproducible, besides being fast and inexpensive.

Resumo em Inglês:

In this paper further information concerning the ecological and biogeographical aspects of scorpionism is presented. Some of the information already outlined in three previous publications(10,14,16) is assessed, and new data given concerning the pattern of distribution presented by Tityus serrulatus in Brazil. Some new ideas are also proposed regarding the possible evolutionary advantages and disadvantages of parthenogenesis versus sexuality in both the short-term and the long-term.

Resumo em Inglês:

Cardioleputin, a new cardioactive toxin, was purified from a stonefish venom using column chromatographies. The purified toxin was found to be an unstable protein that was susceptible to heat and freeze-thawing. This protein showed to have a molecular size of 46,000 daltons, and its amino acid composition was rich in serine and glycine, but low in basic amino acids. The crude venom induced a sudden drop in blood pressure and heart rate of rats right after administration. Both the blood pressure and heart rate returned to their original values as time elapsed, and thereafter continued to show a gradual decrease. In addition, crude venom actively affected the contractile response and suppressed the heart rate of guinea pig atria. The purified toxin caused irreversible inotropical and chronotropical increases in guinea pig atria. The action of the toxin on the atria was completely different from that of lysolecithin. It might be suggested that the toxin acts on the Ca<img SRC="http:/img/fbpe/jvat/v2n2/image2184.gif"> ion channel of the atrial membrane.

Resumo em Inglês:

The profiles of high-performance gel filtration of venoms from Polybia paulista, Polybia ignobilis and Polybia occidentalis occidentalis showed 13 peaks distributed among the three species. These profiles presented similarities that permitted the chromatographic characterization of the genus Polybia and differences that permitted the identification of each species studied. Thus, the comparative analysis of chromatographic profiles of high-performance gel filtration of venoms may be used as an auxiliary tool in taxonomic studies of Polybia wasps.

Resumo em Inglês:

Experiments were carried out in vivo by injecting Tityus serrulatus crude venom in rats followed by biological assays on the isolated guinea-pig ileum, to show the effects of scorpion venom on kallikrein-kinin system. Our results showed effects such as significant decrease of total kinin rate and a decrease of Zn<img SRC="image2229.gif"> , Na<img SRC="image2227.gif"> , Cl<img SRC="image2228.gif"> and K<img SRC="image2227.gif"> ions in rat urine 24 and 48 hours after the injection of Tityus serrulatus crude venom.