Inflammatory lesion and parasite load are inversely associated in Leishmania amazonensis infected mice genetically selected according to oral tolerance susceptibility.

Two strains of mice selected according to extreme phenotypes of susceptibility and resistance to oral tolerance (TS and TR mice, respectively) were infected with 1 x 10(7) Leishmania amazonensis promastigotes and studied comparatively. TS mice developed a minor pathology while permitting parasite growth with the presence of increased IL-4, IL-10 and IFN-gamma, and lower NO and IL-2 levels and delayed-type hypersensitivity (DTH). In contrast, in TR mice, footpad swelling was increased but parasite growth was reduced. They produced lower IL-4, IL-10 and IFN-gamma but increased NO, IL-2 levels, DTH, activated spleen macrophages and periarteriolar lymphoid sheaths. The results suggest that the tolerogenic TS mouse profile, with higher IL-10 production, impaired lesion development but also avoided macrophage leishmanicidal activity, maintaining in this manner a silent parasite load. On the other hand, the TR mouse profile contributed to lesion progression with controlled parasite load. To directly address the influence of oral tolerance on infection, mice were gavaged with OVA, and 7 days afterwards were infected and challenged to bystander suppression with OVA in the same footpad. In TR mice gavaged with 25 mg OVA the inflammatory lesion was largely enhanced, while with 5 mg OVA the lesion was diminished. In TS mice the footpad swelling was always lower. However, the bystander effect did not modify the establishment of infection; and similarly to the control non-bystander mice, parasite clearance was maintained in TR and prevented in TS mice. Therefore, a better comprehension of immunoregulation of innate and adaptive immunity in the early stages of infection is necessary for the development of protocols preventing inflammation and contributing to the elimination of parasites.

Estudo comparativo entre o Doppler Ultra-Som e a arteriografia convencional no diagnóstico das obstruções das artérias digitais no membro torácico do eqüino (Equus caballus)

A presente pesquisa objetivou comparar os traçados do Doppler Ultra-Som (método não-invasivo) e as imagens da arteriografiaconvencional (método invasivo padrão) frente ao diagnóstico das obstruções das artérias digitais do membro torácico noeqüino. Utilizou-se um aparelho de Doppler Ultra-Som bidirecional de ondas contínuas para examinar a artéria digital palmarcomum 11, a artéria digital palmar própria mediai e a artéria digital palmar própria lateral de 11 eqüinos de equitação, sem raçadefinida, com idade variando entre 16 e 24 anos. Obtiveram-se nos três segmentos arteriais estudados 66 resultados destemétodo, sendo sete positivos para obstrução. Subseqüentemente realizaram-se 22 exames arteriográficos nos membrostorácicos, obtendo-se 66 arteriografias, onde foram evidenciadas nove obstruções nos segmentos arteriais estudados. Aosresultados de ambos os métodos foi aplicado o teste de Qui-quadrado (p 0,05). O Doppler Ultra-Som demonstrou umasensibilidade de 77,7% e uma especificidade de 100% quando comparado à arteriografia. Conclui-se que o método doDoppler Ultra-Som é valioso no diagnóstico das obstruções das artérias digitais dos membros torácicos no cavalo, principalmentequando se quer evitar métodos invasivos de diagnóstico (arteriografia).