Among the different infective stages that Trypanosoma cruzi employs to invade cells, extracellular amastigotes (EAs) have recently gained attention by our group. This is true primarily because these amastigotes are able to infect cultured cells and animals, establishing a sustainable infective cycle. EAs are thus an excellent means of adaptation and survival for T. cruzi, whose different infect...

Formycin B is metabolized by cutaneous Leishmania amastigotes within cultured human macrophages to give formycin B 5'-monophosphate and formycin A 5'-mono-, di-, and triphosphates. Formycin A is also incorporated into RNA. The activity of formycin B against amastigotes was correlated with the levels of formycin A metabolites formed in the parasites. Uninfected macrophages also convert formycin ...

A 5-month old puppy with muco-cutaneous lesions in the chin, around lips and eyes was examined physically and microscopically for leishmaniasis. Muco-cutaneous lesions containing a large number of amastigotes of Leishmania spp. were observed. Amastigotes were also detected in liver and spleen of the puppy. The animal was positive with Dipstick rK39 kit and high level of anti-Leishmania antibodi...

Amastigotes (tissue forms) of Leishmania donovani isolated from infected hamster spleens carried out several physiological activities (respiration, catabolism of energy substrates, and incorporation of precursors into macromolecules) optimally at pH 4.0 to 5.5. All metabolic activities that were examined decreased sharply above the optimal pH. Promastigotes (culture forms), on the other hand, c...

Studies were carried out aiming at comparing the uptake of the three evolutionary stages of Trypanosoma cruzi by mouse peritoneal macrophages, influenced by specific immunosera. Incorporation of T. cruzi by macrophages was time dependent. In absence of antibody, trypomastigotes are forms more effectively incorporated by macrophages. Pre-incubation of macrophages with specific sera against each ...

Nowadays, there are no simple techniques for mimicking in vitro the life cycle of the kinetoplasmtid Trypanosoma cruzi Chagas, 1909, causative agent of Chagas disease, especially for parasite strains maintained as epimastigotes for many years. In the present study, we propose a method for obtaining metacyclic trypomastigotes, which were capable of infecting mammalian cells by simply lowering pH...

Differential display technique was applied in order to identify transcripts which are present in axenic amastigotes but not in promastigotes of the Leishmania panamensis parasites. One of them was cloned and the sequence reveals an open reading frame of 364 amino acids (approximately 40 kDa). The deduced protein is homologous to the serine/threonine protein kinases and specially to the mitogen ...

BACKGROUND Kala-azar is a multisystem infection of the reticuloendothelial system. Various hematologic abnormalities have been described in kala-azar including hemophagocytic syndrome (HPS).  METHODS We reviewed bone marrow aspirate smears from 18 documented cases of kala-azar complicated by HPS.  RESULTS The bone marrow smears were hypercellular with erythroid hyperplasia. Megaloblastic ch...