Ana Amélia Carraro Abrahão

Efecto de la infección aguda por diferentes cepas de Trypanosoma cruzi sobre el crecimiento intrauterino de fetos de ratón

old, were i.p. inoculated with 2 x 10 5 trypomastigotes blood stream of T. cruzi (Colombian, Y, Bolivia or RC strains). The results allow to conclude that the T. cruzi infection affect the intrauterine growth of the mouse fetus, with reduction of both weight and length, umbilical cord length, body weight to placenta weight ratio and body weight to umbilical cord length ratio. T. cruzi strains showed different behavior. In general, the less prejudicial to the fetal growth was the RC strain, whereas the most prejudicial were the Bolivia and Y strains. The parasitemic curves of these strains show the most rapid growth, reaching the peak at the 5th and 7th day, respectively. As inoculation was made to agree the last pregnancy day with the parasitemic peak, the infected animals had the most rapid infection with elevated parasitemy, without possibility of maternal adaptation.

Oral myiasis in an elderly patient

BACKGROUND Myiasis is the invasion of living tissue of humans and other mammals by eggs or maggots of flies of the order of Diptera. It occurs mainly in the Tropics and is associated with inadequate public and personal hygiene. Oral myiases in an older man appears to be rare. OBJECTIVE To relate a case of oral myiases in a debilitated older man treated by mechanical removal of the maggots, identifying the adult insect that caused the infestation. METHODS The diagnosis of oral myiasis was established by the clinical examination and it was detected that the infestation involved only soft tissue and the sinus cavity. The patient was submitted to two mechanical removal of the visible maggots. RESULTS Total of 110 maggots was removed from the oral cavity of the patient and adult insects was identified as belonging to the Calliphoridae Family, Cochliomyia hominivorax species. The patient died two days after the second procedure by severe systemic complications. CONCLUSIONS The mechanic removal and the identification of the maggots must be adopted as soon as possible to prevent further tissue damage and bacterial infection in cases of oral myiasis. Special attention should be given to the debilitated old patients that are particularly susceptible to oral myiasis infestation.

Does l-arginine availability during the early pregnancy alters the immune response of Trypanosoma cruzi infected and pregnant Wistar rats?

Chagas disease induces a strong immune response and L-arginine is an essential amino acid which plays an important role in homeostasis of the immune system. The aims of this study were to evaluate parasitemia, corticosterone levels, production of nitric oxide (NO), fetal morphological measurements, and histology of heart and placenta. Twenty pregnant Wistar rats (180-220 g) were grouped in: pregnant control (PC), pregnant control and L-arginine supplied (PCA), pregnant infected (PI), pregnant infected and L-arginine supplied (PIA). Females were infected with 1×10(5) trypomastigotes of the Y strain (3rd day of pregnancy). Animals were supplied with 21 mg of L-arginine/kg/day during 14 days. PIA showed significant decreased levels of corticosterone and parasitemia. For control groups, any alteration in NO production was found with L-arginine supplementation; for PIA, enhanced nitrite concentrations were observed as compared to PI. Weights and lengths of fetuses were higher in L-arginine treated and infected pregnant rats as compared to untreated ones. Placental weight from the PIA group was significantly increased when compared to PI. In L-arginine treated animals, cardiac tissue showed reduced amastigote burdens. PIA and PI displayed similar placental parasitism. Based on these results, L-arginine supplementation may be potentially useful for the protection against Trypanosoma cruzi during pregnancy.

Influence sexual dimorphism on the persistence of blood parasites in infected Calomys callosus.

Gender has long been known to be a contributory factor in the incidence and progression of disorders associated with immune system disregulation. The aims of this experiment were to verify the influences of sexual dimorphism on the persistence of blood parasites out of the acute phase of infection. Male and female Calomys callosus were separated and infected with two strains of Trypanosoma cruzi, and let age until 120 days. Xenogiagnostic, culture of organs and blood, histopathology and lytic antibody percentages were evaluated on late chronic phase. Xenodiagnosis, hemoculture and lytic antibody percentages were positive from 45 until 120 days. For both strains in adrenal and heart, amastigote burdens were present until 45 days, scarcely found on 60 days and absent on 120 days. Steroid hormones, although having a protective role, does not enable animals to get completely rid of the infection. Even without showing apparent signs of pathological unbalance, parasites persists, hidden throughout the hosts body.

Estudio Cariométrico de Placentas de Ratones con Infección Aguda por Diferentes Cepas de Trypanosoma cruzi

El objetivo de este trabajo fue evaluar cariometricamente las alteraciones causadas por diferentes cepas de T. cruzi en la placenta del raton. Ratones hembras de 60 dias, gravidas, fueron inoculadas, intraperitonealmente, con 2 x 105 tripomastigotes sanguineos de las cepas colombiana, Y, Solivia o RC del T. cruzi. Fueron observadas claras diferencias en las alteraciones cariometricas de las celulas trofoblasticas gigantes y de las celulas trofoblasticas de la zona esponjosa. Los resultados demostraron que las cepas colombiana y RC causan alteraciones tanto en las celulas trofoblasticas gigantes como en las celulas del trofoblasto esponjoso, mientras que las cepas Y y Bolivia provocan alteraciones solamente en las celulas trofoblasticas gigantes. Es posible concluir que cada cepa posee caracteristicas propias y que, a pesar del tipo similar de transmision, presenta matices diferenciales en el proceso de la patogenesis placentaria.

Estudio Morfométrico del Hígado de Ratón en la Enfermedad de Chagas Experimental

El objetivo de este trabajo fue caracterizar histopatologicamente y morfometricamente las alteraciones del tejido hepatico de raton, durante la fase aguda de la infeccion por la cepa MORC-2 de Trypanosoma cruzi. Esta cepa mostro acentuado tropismo por el higado, con numerosos nidos de amastigotes en los cortes examinados. El higado de los animales infectados estaba constituido por celulas menores, con citoplasma granuloso. En algunas areas, los sinusoides estaban congestionados y las celulas de Kupffer hipertroficas e hiperplasicas. El tejido hepatico mostro focos circunscritos de celulas inflamatorias en areas de necrosis, sinusoides, en torno de las venas centrolobulillares y de los espacios porta. La vena centrolobulillar estaba dilatada y congestionada, con necrosis focales y ruptura de la pared en algunos campos. Los espacios porta estaban desorganizados, a veces, con intenso infiltrado inflamatorio. En algunas areas fue posible observar degeneracion cistica (spongis hepatis). Por todo el tejido hepatico se observaron nidos de amastigotes, de tamano variable, algunos rodeados por infiltrado inflamatorio cronico. En el espacio porta, el volumen relativo de los conductos biliares y vasos sanguineos, asi como la densidad de superficie de las arterias fueron mayores en el grupo infectado

Histological and morphometric investigations of changes induced by the RAL strain of Trypanosoma cruzi in the mouse placenta

Pregnant Swiss mice (Mus musculus) were inoculated intraperitoneally with 2 x 105 trypomastigotes of the RAL strain of Trypanosoma cruzi on the 7th day of pregnancy and sacrificed on the 19th day of pregnancy. The placenta was sectioned for the assessment of histological and morphometric changes. The RAL strain showed intense tropism for the placenta, with parasitism reaching the three placental layers. There was involvement of the maternal and fetal portions of the placentas, and also of giant cells and spongioblasts. The placentas of infected animals presented sparse areas of degeneration and necrosis, with mild dystrophic calcification of the decidua. The inflammatory process consisted of plasmocytes and lymphocytes, revealing involvement of the decidua. Cytometric study of giant trophoblastic cells showed that the placentas of the infected group were seriously affected, also with respect to cell volume. The changes provoked by the RAL strain in the trophoblastic cells and the difference in behavior observed in the cell population of the various placental regions may affect intrauterine development, probably by a deficient production of hormones such as placental lactogen, which acts as a fetal growth hormone, or indirectly by deficient tissue invasion caused by inefficient utero-placental vascularization, thus impairing fetal nutrition.

Trypanosoma cruzi: Do different sylvatic strains trigger distinct immune responses?

Strains of Trypanosoma cruzi are multiclonal populations that can be classified in groups or genotypes, differing in pathogenicity, virulence, and histotropism. In this experiment the distinct behavior of two strains of T. cruzi, MORC-1 and MORC-2, was documented. Blood parasitemia, spleen proliferation, nitric oxide, histopathology of the spleen and heart were used as tools to evaluate parasite persistence. Groups of male mice were separated and divided in three groups: Control (C), Infected (IM-1) and Infected (IM-2). The peak of parasitemia occurred on 10days post infection for both strains. LPS stimulated animals, infected MORC-2 group displayed significant higher concentrations of NO when compared to infected MORC-1 group (P<0.05). For ConA stimulated lymphoproliferation, infected MORC-1 group displayed higher proliferation index as compared to infected MORC-2 group. An opposite behavior for IL-4 and TNF-alpha was observed according to the strain. For MORC-1 enhanced concentrations of IL-4 were present with concomitant reduced levels of TNF-alpha, while for MORC-2 enhanced concentrations of TNF-alpha and reduced levels of IL-4 were found. The histopathology of heart and spleen showed important differences in which MORC-1 displayed statistically enhanced number of amastigote in the heart and spleen as compared to MORC-2. Concluding, each strain triggered a distinct immune response with enhanced cytokine TH-1 profile for MORC-2 and TH-2 for MORC-1.

Morfometría de la Parótida de Ratón Infectado por la Cepa RAL de Trypanosoma cruzi en Función del Sexo

Fueron estudiadas las alteraciones y el nivel de deterioro de las parotidas de animales infectados con la cepa RAL de Trypanosoma cruzi. Se utilizaron ratones albinos (Mus musculus) de ambos sexos, debido al dimorfismo sexual de las glandulas salivares, inoculados con 2 x 104 tripomastigotes sanguineos de la cepa RAL del T. cruzi. Los animales fueron sacrificados al 12° dia de infeccion, coincidiendo con el pico parasitemico. La parotida fue procesada histologicamente y, posteriormente, evaluada histopatologica y morfometricamente. Los resultados permitieron verificar intenso parasitismo en la glandula, la que presento desorganizacion estructural y atrofia generalizada de acinos y conductos, mas intensos en las hembras. Concluyendo, la cepa RAL del T. cruzi mostro un comportamiento atipico en relacion a otras cepas, causando modificaciones mas evidentes en las hembras, debido, posiblemente, a alteraciones hormonales desencadenadas por el T. cruzi