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178 results on '"Rodrigues-Simioni, L."'

7. INTRASPECIFIC VARIATION IN NEUROTOXIC AND MYOTOXIC ACTIVITIES OF Bothrops neuwiedii VENOMS

Author

BORJA-OLIVEIRA, C. R., SOARES, A. M., ZAMUNÉR, S. R., HYSLOP, S., GIGLIO, J. R., PRADO-FRANCESCHI, J., and RODRIGUES-SIMIONI, L.

Subjects
myotoxicity, neuromuscular blockade, intraspecific variation, neurotoxicity, complex mixtures, Bothrops neuwiedii venom
Abstract

Snake venoms frequently vary in composition. In this work, we compared the neurotoxic and myotoxic activities of 16 lots of Bothrops neuwiedii venoms from different regions of Brazil, using chick biventer cervicis preparations. The neuromuscular blockade varied from 2% to 100% after 120 min incubation with venoms (50 mug/ml). In all cases, this blockade was irreversible and concentration-dependent; at low concentrations (10-20 mug/ml), 15 of the 16 venom lots failed to abolish responses to acetylcholine (110 muM), but blocked responses to KCl (13.4 muM), and induced contracture. At 5-20 mug/ml, the most active venom totally blocked twitch-tension without affecting responses to acetylcholine and KCl. Polyacrylamide gel electrophoresis for basic proteins showed that the most active samples contained a band that was absent in the less active venoms. These results indicate that there may be considerable intraspecific variation in the neurotoxic activity of B. neuwiedii venoms, whereas myotoxic activity is less variable.

Published
2002

8. Histopathological changes in avian kidney caused by Bothrops insularis (jararaca ilhoa) venom and a phospholipase A2-containing fraction

Author

da Cruz Hoflingl, M.A., Paronetto, C.C.L., Cogo, J.C., Rodrigues-Simioni, L., and D'Abreu, A.C.F.

Subjects
Avian, 6 - Ciencias aplicadas::61 - Medicina::615 - Farmacología. Terapéutica. Toxicología. Radiología [CDU], Kidney, complex mixtures
Abstract

The histopathological changes induced in avian kidney by the intramuscular injection of Bothrops insularis (jararaca ilhda) venom and its phospholipase A2 (PLA2)-containing fraction were examined. Acute experiments (3 h and 24 h) with B. insularis crude venom (20 pg and 80 pg) or its PLA2-contaning fraction (10 pg and 40 pg) resulted in significant structural damage to the kidneys of 5-12-day-old chicks. Histopathological analysis indicated that the venom and its fraction acted on the renal tubules and glomeruli. The morphological changes, although widespread, varied in intensity from cell to cell, and from tubule to tubule in venom-injected chicks. The tubular and glomerular changes produced by the venom and its PLA2-containing fraction may be the result of a direct cytotoxic effect potentiated by ischemia-related disturbances in the regional hemodynamics. The venom and its fraction affected more segments along reptilian-type nephrons than along mammalian ones. This divergent sensitivity to the venom and its fraction may reflect the speciesspecific characteristics of B. insularis snake, an example of geographical isolation influencing its diet which is almost exclusively avian.

Published
2001

43. Antibothropic action of Casearia sylvestris Sw. (Flacourtiaceae) extracts.

Author

Cintra-Francischinelli, M., Silva, M. G., Andréo-Filho, N., Gerenutti, M., Cintra, A. C. O., Giglio, J. R., Leite, G. B., Cruz-Höfling, M. A., Rodrigues-Simioni, L., and Oshima-Franco, Y.

Abstract

Casearia sylvestris Sw., popularly known in Brazil as 'guaçatonga', has been used as antitumor, antiseptic, antiulcer, local anaesthetic and healer in folk medicine. Snakebite envenomation by Bothrops jararacussu (Bjssu) constitutes a relevant public health hazard capable of inducing serious local damage in victims. This study examined the pharmacological action of apolar and polar C. sylvestris leaf extracts in reverting the neuromuscular blockade and myonecrosis, which is induced by Bjssu venom and its major toxin bothropstoxin-I on the mouse phrenic nerve-diaphragm preparations. The polar methanol extract (ME) was by far the most efficacious. ME not only prevented myonecrosis and abolished the blockade, but also increased ACh release. Such facilitation in neuromuscular transmission was observed with ME alone, but was accentuated in preparations incubated with ME plus venom or toxin. This established synergy opens an interesting point of investigation because the venom or toxin in contact with ME changes from a blocking to a facilitating effect. It is suggested that rutin, known to have potent antioxidant properties, and one of the components present in the ME, could have a role in the observed effects. Since commercial rutin did not reproduce the ME effects, it is likely that a rutin-containing phytocomplex is neutralizing the bothropic envenoming effects. Copyright © 2008 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Published
2008
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45. Determination of Primary Structure of Two Isoforms 6-1 and 6-2 PLA2D49 from Bothrops jararacussuSnake Venom and Neurotoxic Characterization Using in vitroNeuromuscular Preparation

Author

Ponce-Soto, L., Bonfim, V., Rodrigues-Simioni, L., Novello, J., and Marangoni, S.

Abstract

In this paper we reported the purification, the biological characterization and the amino acid sequence of two new isoforms basic 6-1 (Bj-IV) and 6-2 (Bj-V) PLA2D49 purified from the Bothrops jararacussuvenomIn this paper we reported the purification, the biological characterization and the amino acid sequence of two new isoforms basic 6-1 (Bj-IV) and 6-2 (Bj-V) PLA2D49 purified from the Bothrops jararacussuvenom

Published
2006
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46. Cross-neutralization on the histamine-releasing activity of snake venoms

Author

EDSON ANTUNES, Rodrigues-Simioni L, and Prado-Franceschi J

Subjects
Mice, Antivenins, Crotalid Venoms, Animals, Histamine Release
Abstract

This paper investigates the neutralizing effect of crotalic and bothropic antivenoms on the histamine-releasing activity of three different Brazilian snake venoms (Crotalus durissus terrificus, Bothrops jararacussu and Bothrops alternatus). This relative histamine-releasing activity was determined on peritoneal mixed cells of rats. C. d. terrificus venom was the most efficient histamine-releasing agent (ED50 = 1.25 micrograms/ml) followed by B. jararacussu (ED50 = 1.97 ug/ml) and B. alternatus (ED50 = 15.1 ug/ml) venoms. The histamine-releasing effects eventually produced by antivenom sera (antivenoms) were avoided by the use of small volumes of each one (10-20 ul). Both the monovalent crotalic and the polyvalent bothropic antivenoms were able to neutralize the histamine-releasing activity of the three venoms without specificity. This cross-reaction suggests that the main histamine-releasing factor (s) present in these venoms has similar antigenic constitution.

47. Biological characterization of Bothrops marajoensis snake venom

Author

Walter Cavalcante, Hernandez-Oliveira, S., Galbiatti, C., Randazzo-Moura, P., Rocha, T., Ponce-Soto, L., Marangoni, S., Pai-Silva, M. D., Gallacci, M., Da Cruz-Höfling, M. A., Rodrigues-Simioni, L., Universidade Estadual de Campinas (UNICAMP), and Universidade Estadual Paulista (Unesp)

Subjects
Marajó lancehead, Neurotoxicity, Neuromuscular junction, Myotoxicity, Presynaptic effects
Abstract

Made available in DSpace on 2016-07-07T12:36:37Z (GMT). No. of bitstreams: 0 Previous issue date: 2011. Added 1 bitstream(s) on 2016-07-07T12:45:29Z : No. of bitstreams: 1 ISSN2044-0324-2011-02-37-41.pdf: 943442 bytes, checksum: de5846986ac9d173f5d2dba31d6ce61c (MD5) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) This study describes the effects of Bothrops marajoensis venom (Marajó lancehead) on isolated neuromuscular preparations of chick biventer cervicis (CBC) and mouse phrenic nerve-diaphragm (PND). At low concentrations (1µg/ml for CBC and 5µg/ml for PND), the venom exhibited a neuromuscular blocking without any damaging effect on the muscle integrity. At higher concentration (20µg/ml for PND), together with the neuromuscular blockade, there was a moderate myonecrosis. The results show differences between mammalian and avian preparations in response to venom concentration; the avian preparation was more sensitive to venom neurotoxic effect than the mammalian preparation. The possible presynaptic mechanism underlying the neuromuscular blocking effect was reinforced by the observed increase in MEPPs at the same time (at 15min) when the facilitation of twitch tension occurred. These results indicate that the B. marajoensis venom produced neuromuscular blockade, which appeared to be presynaptic at low concentrations with a postsynaptic component at high concentrations, leading to muscle oedema. These observations demand the fractionation of the crude venom and characterization of its active components for a better understanding of its biological dynamics. Universidade Estadual de Campinas, Departamento de Farmacologia, Faculdade de Ciências Médicas Universidade Estadual de Campinas, Departamento de Histologia e Embriologia, Instituto de Biologia Universidade Estadual de Campinas, Departamento de Bioquímica, Instituto de Biologia Universidade Estadual Paulista, Departamento de Morfologia, Instituto de Biociências de Botucatu Universidade Estadual Paulista, Departamento de Farmacologia, Instituto de Biociências de Botucatu

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