Associative behaviour and antagonism of bovine rumen ciliate (Protista, Ciliophora) from Zona da Mata, Minas Gerais State, Brazil

Aiming at obtaining the community profile and verifying the occurrence of antagonism and association among ciliates, samples of rumen content were analysed in 100 bovines soon after their death. The animals were killed at the Juiz de Fora Municipal slaughter house (Juiz de Fora, Minas Gerais State, Brazil) between August 1996 and May 1997. Ciliates occurred, respectively, in the following percents and samples number: Entodinium Stein, 1859 (50,48; 100), Diplodinium Schuberg, 1888 (5,59; 98), Eudiplodinium Dogiel, 1927 (6,91; 97), Ostracodinium Dogiel, 1927 (9,68; 95), hotricha Stein, 1859 (4,15; 93), Dasytricha Schuberg, 1888 (3,31; 93), Metadi nium Awerinzew & Mutafowa, 1914 (3,06; 90), Eremoplastron Kofoid & MacLennan. 1932 (7,39; 87), Epidinium Crawley, 1923 (5,31; 73), Charonina Strand, 1928 (1,33; 65), Eodinium Kofoid & MacLennan, 1932 (1,49; 59), Diploplastron Kofoid & MacLennan, 1932 (0,88; 24), Elytroplastron Kofoid & MacLennan, 1932 (0,36; 16), Polyplastron Dogiel, 1927 (0,04; 03) and Buetschlia Schuberg, 1888 (0,02; 01). When the antagonistic behaviour and the association were analyzed, it was observed that Eudiplodinium was detected in the absence of Polyplastron and in the presence of Epidinium in 94% and 73% of the samples, respectively. These data confirm the antagonism and the coexistence among particular populations of rumen ciliates and allowed the identification of 94% of the samples examined as being of profile type B, none of type A and 3% of mixed A-B community and of type O. It is suggested the use of the term community profile instead of population profile, as the respective types involve associations of various ciliate populations.

Imunocompetent Mice Model for Dengue Virus Infection

Dengue fever is a noncontagious infectious disease caused by dengue virus (DENV). DENV belongs to the family Flaviviridae, genus Flavivirus, and is classified into four antigenically distinct serotypes: DENV-1, DENV-2, DENV-3, and DENV-4. The number of nations and people affected has increased steadily and today is considered the most widely spread arbovirus (arthropod-borne viral disease) in the world. The absence of an appropriate animal model for studying the disease has hindered the understanding of dengue pathogenesis. In our study, we have found that immunocompetent C57BL/6 mice infected intraperitoneally with DENV-1 presented some signs of dengue disease such as thrombocytopenia, spleen hemorrhage, liver damage, and increase in production of IFNγ and TNFα cytokines. Moreover, the animals became viremic and the virus was detected in several organs by real-time RT-PCR. Thus, this animal model could be used to study mechanism of dengue virus infection, to test antiviral drugs, as well as to evaluate candidate vaccines

IgG isotype profile is correlated with cardiomegaly in Beagle dogs infected with distinct Trypanosoma cruzi strains.

A systematic study following infection by various strains of the protozoan parasite, Trypanosoma cruzi, and the simultaneous monitoring of the humoral immune response together with the elicited cellular response, could add greatly to our understanding of differences between strains of this important human pathogen. In that sense, acute and chronic infections with distinct T. cruzi strains (Y, Berenice-78 and ABC) in Beagle dogs were studied through a longitudinal evaluation of immunoglobulin G (IgG), IgG1 and IgG2 isotypes (by ELISA and flow cytometry (FC)), as well as measurements of peripheral blood mononuclear cell (PBMC) proliferation over a 100-week period, and their correlation with cardiomegaly. Our results show that infected animals presenting cardiomegaly showed lower or absent levels of IgG1 during the chronic phase of the infection, when compared to those that did not show an increase in heart weight. In that manner, our results suggest that IgG1 could be used as a marker for cardiac pathogenicity in Chagas disease

Hematological alterations during experimental canine infection by Trypanosoma cruzi

To confirm that Beagle dogs are a good experimental model for Chagas disease, we evaluated hematological alterations during the acute and chronic phases in Beagle dogs infected with the Y, Berenice-78 (Be-78) and ABC strains of Trypanosoma cruzi, correlating clinical signs with the parasitemia curve. We demonstrate that the acute phase of infection was marked by lethargy and loss of appetite. Simultaneously, we observed anemia, leukocytosis and lymphocytosis. Also,we describe hematological alterations and clinical signs that were positively correlated with the parasitemia during the experimental infection with the three strains of T cruzi, and demonstrate that experimental infection of Beagle is a trustworthy model for Chagas disease.Research Support Foundation of the State of Minas Gerais (FAPEMIG)Research Support Foundation of the State of Minas Gerais (FAPEMIG)National Research Council for Scientific and Technological Development (CNPq)National Research Council for Scientific and Technological Development (CNPq)Coordination Office for Advancement of Universitylevel Personnel (CAPES)Coordination Office for Advancement of University-level Personnel (CAPES

IL-17 Produced during Trypanosoma cruzi Infection Plays a Central Role in Regulating Parasite-Induced Myocarditis

Chagas disease is caused by the intracellular parasite Trypanosoma cruzi. This infection has been considered one of the most neglected diseases and affects several million people in the Central and South America. Around 30% of the infected patients develop digestive and cardiac forms of the disease. Most patients are diagnosed during the chronic phase, when the treatment is not effective. Here, we showed by the first time that IL-17 is produced during experimental T. cruzi infection and that it plays a significant role in host defense, modulating parasite-induced myocarditis. Applying this analysis to humans could be of great value in unraveling the elements involved in the pathogenesis of chagasic cardiopathy and could be used in the development of alternative therapies to reduce morbidity during the chronic phase of the disease, as well as clinical markers of disease progression. The understanding of these aspects of disease may be helpful in reducing the disability-adjusted life years (DALYs) and costs to the public health service in developing countries

Correlação entre as lesões cardíacas e a resposta imune em cães da raça Beagle infectados experimentalmente com diferentes cepas do Trypanosoma cruzi.

Exportado OPUSMade available in DSpace on 2019-08-13T07:45:35Z (GMT). No. of bitstreams: 1 tese_paulo_guedes.pdf: 1576482 bytes, checksum: 078fac6fd2bfe596fd48489ca90a81bd (MD5) Previous issue date: 1RESUMOCom a finalidade de compreender melhor a gênese das lesões na miocardiopatia chagásica crônica humana, cães da raça Beagle foram infectados com cepas do Trypanosoma cruzi que apresentam diferentes graus de virulência e patogenicidade. Foram analisadas características biológicas inerentes as cepas do parasito (polimorfismo de formas tripomastigotas, infectividade in vitro, curva de parasitemia) e aspectos da resposta imune do hospedeiro (cinética de produção de imunoglobulinas IgA, IgM, IgG, IgG1 e IgG2; produção de anticorpos líticos; proliferação de células mononucleares do sangue periférico/CMSP; dosagem de citocinas in situ no linfonodo cervical e no átrio direito) correlacionando com as alterações cardíacas (cardiomegalia, inflamação e fibrose presentes no miocárdio) durante as fases aguda (eutanásia: 30 dias após a infecção) e crônica (dois anos após a infecção). As cepas Y e ABC do T. cruzi que apresentaram alta infectividade in vitro, quando foram inoculados em cães, os níveis de parasitemia foram mais elevados que aqueles observados com a cepa Berenice-78. Todos os animais infectados mostraram o mesmo perfil de resposta proliferativa CMSP. Não houve diferença nos níveis de anticorpos dos isotipos IgA, IgM e de anticorpos líticos nos animais infectados com as três cepas do T. cruzi. Entretanto, os anticorpos IgA juntamente com IgM pode ser utilizado como marcador de fase aguda da infecção. Os níveis de anticorpos detectados na sorologia convencional (SC) e na citometria de fluxo (CF) (IgG total e IgG2) foram similares e detectados a partir de 15 dias da inoculação na maioria dos animais infectados. Por outro lado, altos níveis de IgG1 foram detectados na SC e na CF nos soros dos animais infectados com a cepa Berenice-78, enquanto foram ausentes ou detectados em níveis baixos naqueles infectados com as cepas Y e ABC, e negativos nos animais não infectados. Durante a fase aguda, todos os animais infectados apresentaram linfadenopatia e esplenomegalia e somente 50% (cepas Y e ABC) e 25% (Berenice-78) dos animais infectados apresentaram discreta cardiomegalia. Também foi observada uma severa miocardite em todos os animais infectados. Na fase crônica, somente 50% e 25% dos animais infectados com as cepas Berenice-78 e ABC, respectivamente, apresentaram linfadenopatia. No entanto, todos animais permaneceram com esplenomegalia, porém menos intensa que na fase aguda. A cardiomegalia, a inflamação e a fibrose foram observadas em 100%, 50% e 100% dos animais infectados com as cepas Y, Berenice-78 e ABC, respectivamente. A produção de IFN-, TNF e IL-10 in situ (linfonodo cervical e átrio direito) durante a fase aguda foi similar em todos os animais infectados. Entretanto, durante a fase crônica os níveis de produção destas citocinas foi semelhante nos linfonodos dos animais infectados enquanto na área cardíaca somente aqueles infectados com a cepa Berenice-78 produziram IL-10. Esses dados indicam que a alta produção de IgG1 e IL-10 in situ (resposta anti-inflamatória) durante esta fase podem estar correlacionadas com a forma indeterminada da doença, enquanto a baixa produção de IgG1 e IL-10 estariam associadas a forma cardíaca da doença

Caracterização das populações de ciliados (Protista, Ciliophora) do rúmen de bovinos de corte no estado de Minas Gerais, Brasil

Aiming at contributing to the knowledge of the relationships between bovines and rumen ciliates that naturally occur in Brazilian beef cattle, this paper presents a survey of these ciliate populations in bovines killed in Juiz de Fora Municipal Slaughterhouse, Minas Gerais State, Brazil. Material samplings were carried out monthly from August 1996 to May 1997, totalizing 100 bovines. All rumen contents samples were obtained from recentlyslaughtered animals, cross-bred holstein friesianzebu, kept in Brachiaria decumbens grass. The ciliates were quantified in a Sedgewick-Rafter chamber. The ciliate genus found and the corresponding total and average numbers, relative composition in the population and prevalence were the following: Entodinium (5.163.200; 51.632; 50,48; 100), Diplodinium (572.000; 5.837; 5,59; 98), Eudiplodinium (706.400; 7.283; 6,91; 97), Ostracodinium (989.599; 10.417; 9,68; 95), Isotricha (424.400; 4.563; 4,15; 93), Dasytricha (338.800; 3.643; 3,31; 93), Metadinium (312.800; 3.476; 3,06; 90), Eremoplastron (756.000; 8.690; 7,39; 87), Epidinium (543.200; 7441; 5,31; 73),Charonina (136.400; 2.099; 1,33; 65), Eodinium (152.400 2.583; 1,49; 59), Diploplastron (90.000; 3.750; 0,88; 24), Elytroplastron (36.400; 2.275; 0,36; 16), Polyplastron (3.600 1.200; 0,04; 03) e Buetschlia (2.000; 2.000; 0,02; 01). The populations are characterized as type B in 94% of samples

Advances in Chagas disease chemotherapy.

Chagas disease is endemic from Mexico to Argentina, where it is estimated that 16 to 18 million people are infected with its causative agent, Trypanosoma cruzi, and 100 million remain at risk of infection, emphasizing the necessity to sustain and extend control measures and strategies to combat this disease. Specific chemotherapy with benznidazole or nifurtimox has been recommended for treatment of recent and congenital infection. However, clinical trials with nifurtimox and benznidazole have shown that these compounds have very low activity in preventing the development of chronic Chagas disease. Moreover, the drugs induce a number of toxic side effects. The discovery of new active, non-toxic compounds would probably expand treatment, including those patients in which clinical manifestations are absent or can only be disclosed by more elaborate medical procedures. Recent developments in the study of basic biochemical aspects of T. cruzi have allowed for the identification of new targets for chemotherapy. Like many fungi, T. cruzi has a strict requirement for specific endogenous sterol synthesis for cell viability and growth and is extremely susceptible to sterol biosynthesis inhibitors (SBI). An intensive investigation of the potential trypanocidal effect of specific SBI has been performed, and it was demonstrated that some of these compounds exhibited suppressive and curative activity in murine and dog models of acute and chronic Chagas disease. Other potential targets for anti-T. cruzi chemotherapy that include the antiproliferative lysophospholipid analogs (evaluated in clinical trials as the first oral treatment for visceral leishmaniasis), cysteine protease inhibitors and compounds that interfere with purine salvage and inositol metabolism are also discussed

Benznidazole therapy during acute phase of chagas disease reduces parasite load but does not prevent chronic cardiac lesions.

The goals of this study were to evaluate the efficacy of benznidazole (Bz) treatment in decreasing of the parasitic load during the acute phase of experimental Chagas disease and to analyze its influence in the development of cardiac chronic alterations in mice inoculated with drug-resistant Trypanosoma cruzi strains. Our results showed that the early Bz treatment (started at 4th day of infection) was efficient in reducing the parasite load in animals from both acute and chronic phase of the infection. Moreover, this reduction in the parasite load could not be associated with the intensity of the cardiac chronic lesions. The histopathological evaluation of cardiac tissue of Bz-treated mice showed three different patterns of response: (1) presence of a small number of inflammatory cells and fibrotic area similar to noninfected mice; (2) similar intensity of inflammatory infiltrate and smaller fibrotic area in relation to nontreated animals; (3) similar intensity of inflammatory infiltrated and fibrosis area among the Bz-treated and nontreated animals. Each specific pattern was obtained with different T. cruzi strain, suggesting that the pattern of the heart lesions in chronic phase of Bz-treated animals was T. cruzi strain dependent but not related with drug resistance levels