ABSTRACT
The leishmaniases are severe parasitic diseases that occur worldwide, caused by protozoa of the genus Leishmania. Studies with medicinal plants can lead to a range of possibilities for treating and improving the patients' quality of life. Research on Azadirachta indica fractions and extracts has shown that they have excellent anti-leishmanial activity based on bioactivity-guided fractionation of ethanolic extracts of leaves and seeds and in vitro activity against promastigotes. In this research the most efficient extracts and fractions were selected for tests on intracellular amastigotes of Leishmania amazonensis. The ethanolic extract of the leaves and dichloromethane and chloroform fractions had IC50 values of 38, 3.9 and 1.2 μg/mL for promastigotes and 9.8, 1.1 and 0.6 μg/mL for amastigotes, respectively, at 72 hours. For the ethanolic extract and dichloromethane fraction from nut tegument, the IC50 was 2.7 and 2.1 μg/mL for promastigotes and 0.4 and 0.6 μg/mL for amastigotes. The cytotoxicity of the fractions presented selectivity that was between 8 to 32 times more toxic to promastigotes and 15 to 72 times to amastigotes than to macrophages. The extracts and fractions from leaves and fruits were more effective against amastigotes, and the fractionation increased activity against both promastigotes and amastigotes, enabling us to obtain potentially active fractions with low toxicity.
Subject(s)
Animals , Female , Mice , Antiprotozoal Agents/pharmacology , Azadirachta/chemistry , Leishmania mexicana/drug effects , Plant Extracts/pharmacology , Fruit/chemistry , Mice, Inbred BALB C , Macrophages/drug effects , Parasitic Sensitivity Tests , Plant Leaves/chemistryABSTRACT
Relata-se um caso de ameloblastoma com metástase tardia no pulmäo. O crescimento metastástico apareceu 16 anos após a ressecçäo total da tumoraçäo primária, localizada na mandíbula. Os achados histológicos da metástase foram comparados aos do tumor primitivo, quando se evidenciou uma semelhança entre as duas tumoraçöes. As vias de disseminaçäo do tumor para os pulmöes foram discutidas. No presente caso os autores favorecem a via hematogênica como a mais provável rota de disseminaçäo, apesar de näo afastarem totalmente a possibilidade da metástase através da aspiraçäo de células tumorais. O prognóstico do ameloblastoma maligno com metástase para pulmäo é bastante sombrio. Devido ao pequeno número de pacientes estudados até agora näo foi possível se avaliar os resultados do tratamento radioterápico associado ou näo à poliquimioterapia. Contudo, a julgar pelos poucos relatos na literatura, estas modalidades de tratamento näo trouxeram, até o momento, benefícios para os pacientes com vistas a uma longa sobrevida. A imunoterapia nestes casos situa-se mais como um conceito promissor do que uma realidade terapêutica efetiva