RESUMO OBJETIVO: Além de suas propriedades anticoagulantes, a heparina apresenta efeitos vasodilatadores e anti-inflamatórios que podem ajudar na reversão das alterações sépticas da microcirculação. Este artigo investiga os efeitos da heparina sobre alterações da microcirculação relacionadas com endotoxemia e compara-os com os observados com o uso de proteína C humana recombinante ativada. MÉTODOS: Após os procedimentos de implantação da câmara de dobras cutâneas e indução de endotoxemia por administração intravenosa de lipopolissacarídeo da Escherichia coli (2mg.kg-1), hamsters sírios dourados machos foram tratados com heparina não fracionada intravenosa (0,2 mg. kg-1). A microscopia intravital de preparações de câmara de dobras cutâneas permitiu a análise quantitativa de variáveis microvasculares e venulares, bem como de rolamento e aderência de leucócitos. Parâmetros micro-hemodinâmicos também foram analisados. Hamsters endotoxêmicos tratados com proteína C humana recombinants ativada e animais não tratados serviram como controles. RESULTADOS: A heparina diminuiu o rolamento de leucócitos e a vasoconstricção arteriolar induzida por lipopolissacarídeo e produziu um aumento de sobrevida em comparação com animais não tratados, enquanto proteína C humana recombinants ativada diminuiu a adesão de leucócitos. A administração de heparina mais proteína C humana recombinante ativada resultou numa significativa atenuação dos déficits de perfusão capilar induzida por lipopolissacarídeo. CONCLUSÕES: A heparina produz efeitos protetores sobre a microcirculação dos animais endotoxêmicos. Estas vantagens foram potenciados quando a heparina foi administrada em combinação com proteína C humana recombinante ativada.

OBJECTIVE: Apart from its anticoagulant properties, heparin has vasodilator and anti-inflammatory effects that could assist in the reversal of septic microcirculatory changes. This paper investigates the effects of heparin on endotoxemia-related microcirculatory changes and compares them to those observed with the use of recombinant human activated protein C. METHODS: After skinfold chamber implantation procedures and endotoxemia induction by intravenous Escherichia coli lipopolysaccharide administration (2 mg.kg-1), male golden Syrian hamsters were treated with intravenous unfractionated heparin (0.2 mg.kg-1). Intravital microscopy of skinfold chamber preparations allowed quantitative analysis of microvascular variables and venular leukocyte rolling and adhesion. Macrohemodynamic parameters were also analyzed. Endotoxemic hamsters treated with recombinant human activated protein C and non-treated animals served as controls. RESULTS: Heparin decreased lipopolysaccharide-induced leukocyte rolling and arteriolar vasoconstriction; it also increased survival when compared with non-treated animals, while recombinant human activated protein C decreased leukocyte adhesion. Administration of heparin plus recombinant human activated protein C was associated with a significant attenuation of lipopolysaccharide-induced capillary perfusion deficits. CONCLUSIONS: Heparin yields protective effects on endotoxemic animals' microcirculation. Those benefits were potentiated when heparin was administered in conjunction with recombinant human activated protein C.

Poco se conoce sobre la estructura vocal del Caiman yacare del Pantanal brasileño. Llamadas agresivas de hembras adultas que cuidaban de los nidos fueron registradas durante enero y febrero y llamadas de socorro de caimanes jóvenes, en abril de 1992. Hembras adultas de C. yacare presentaron una vocalización agresiva más larga y compleja que en otras especies más grandes de Alligatoridae. Las vocalizaciones de los jóvenes caimanes también presentaron diferencias interespecíficas con otros cocodrilos y variaciones intraespecíficas entre grupos separados por pocos kilómetros. Se utilizó la Prueba de Mantel para comparar las distancias de Mahalanobis entre la estructura de las vocalizaciones de los jóvenes de acuerdo con sus grupos y las distancias geográficas donde ellos estaban. La distancia geográfica en sí no explica las diferencias en las vocalizaciones de jóvenes de diferentes grupos. Hembras adultas de C. yacare han respondido a grabaciones de llamadas de caimanes de grupos de otras regiones, así como a imitaciones de llamada de socorro. Se postula que las variaciones en las llamadas de socorro pueden estar asociadas con una baja especificidad en el reconocimiento de sonido por caimanes adultos que han respondido de la misma forma protectora a las más heterogéneas expresiones de peligro de los jóvenes.

The Paraguayan caiman (Caiman yacare) is the main Caimaninae species occurring in the Brazilian Pantanal Wetland. Despite the relative availability of works focused on biology and conservation of the Paraguayan caiman, almost nothing is known about its vocal structure and behavior. We recorded aggressive calls of adult caiman females guarding nests and, afterwards, the distress calls of the new born juvenile caimans in seasonally flooded areas of the Nhecolândia (Southern Pantanal). The results of both observations and sonographic analyses diverged from studies with other crocodilian species. Aggressive vocalization of adult females of the Paraguayan caiman was longer and more complex than the same vocalization of larger Alligatoridae species. Vocalizations of the young caimans presented interspecific differences with other crocodilian offsprings. Moreover, we found statistically significant intraspecific variation in the distress call structure among different pods, even separated by few kilometers. Differences in distress call structure were tested by Canonical Discriminant Analysis (CDA). We obtained the squared Mahalanobis distances between the acoustic multivariate spaces of each pod provided by the CDA and compared with the geographic distance between the bays of origin of each pod through Mantel Test. The geographic distance by itself did not explain the differences found in the structure of the vocalization of young caimans from different pods. The adult females of Paraguayan caiman positively responded to playbacks of calls from juvenile caimans from pods of other regions, as well as to rough imitations of distress call. Since the adult caimans showed protective responses to quite heterogeneous vocalizations of distress by juveniles, we hypothesized that the variation in the distress call pattern may be associated to a low specificity in sound recognition by adult caimans.