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Search Results: 1 - 10 of 1403 matches for " Trypanosoma cruzi "
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Heart transplants for patients with Chagas' heart disease
Bocchi, Edimar Alcides;
Sao Paulo Medical Journal , 1995, DOI: 10.1590/S1516-31801995000200021
Abstract: the role of heart transplants for treating chagas' heart disease is not quite clear. immunosuppression could lead to resurgence of t. cruzi infection with acute or chronic damage to the allograft. there are few publications regarding this issue. thus we reported the follow-up of 18-patients with chagas' heart disease submitted to orthotopic heart transplants from 1985 to 1993 at the heart institute. the patients were in functional class iv or iii, or ii, with sustained ventricular tachycardia episodes. the mean left ventricular ejection fraction was 25 ± 9% and the mean right ventricular ejection was 22 ± 6% (muga). immunosuppression was based on cyclosporin, azathioprine and corticosteroids. for specific post-transplant monitoring of t. cruzi infection, blood tests were performed (examination of blood or leukocyte concentrate, giemsa-stained blood smears, blood culture, xenodiagnosis, mouse inoculation) and tissue biopsy (skin or myocardium). in addition, complement fixation hemagglutination and immunofluorescence assays were performed. t. cruzi parasitemias were detected in 18 circumstances in 13 patients. resurgence of chagas' disease was diagnosed in 11 circumstances in 5 patients. fever, subcutaneous nodules and myocarditis predominated in these episodes. all episodes of parasitemia and chagas' disease resurgence were successfully treated with benzonidazole. all surviving patients had normal cardiac function despite left ventricular function worsening during some myocarditis episodes. neoplasias were important findings and 3 patients developed lymphoproliferative disease, 2 developed karposi's sarcoma and 1 patient developed skin cancer. the survival rates at 4 and 12 months were 83% and 49% respectively. the survival of patients who underwent heart transplants from august 1991 to april 1993 was 100% at 4 months and 75% at 12 months. heart transplants for chagas' heart disease may be associated with episodes of parasitemia and a reoccurrence of episodes of chag
Localización cromosómica de los genes KMP-11 en cepas KP1(+) y KP1 (-) de Trypanosoma rangeli
Urue?a,Claudia; Santander,Paola; Díez,Hugo; Montilla,Marleny; Zarante,Ignacio; Thomas,María del Carmen; López,Manuel Carlos; Puerta,Concepción;
Biomédica , 2004,
Abstract: genes encoding for the kmp-11 protein were localized on the chromosomes of trypanosoma rangeli. these genes were located in two chromosomes of 3,100 and 3,400 kb in the kp1(-) strain whereas in the kp1(+) h14 and choachí strains, the genes are located in a chromosome of 1,600 kb. the choachí strain presents an additional band of 1,400 kb. in the shubacbarina and munanta strains of trypanosoma cruzi, the kmp-11 genes are located on a chromosomal band of 1,490 kb. therefore, the chromosomal localization of the kmp-11 genes presents a potential tool to differentiate among these parasites.
Synthesis and Trypanocidal Evaluation of Some Novel 2-(Substituted Benzylidene)-5, 7-Dibromo-6-Hydroxy-1-Benzofuran-3(2H)-Ones  [PDF]
K. L. Ameta, Nitu S. Rathore, Biresh Kumar, Edith S. Malaga M, Manuela Verastegui P, Robert H. Gilman, B. L. Verma
International Journal of Organic Chemistry (IJOC) , 2012, DOI: 10.4236/ijoc.2012.223040
Abstract: Substituted 2-benzylidene-1-benzofuran-3-ones are commonly known as aurones. This class of bioactive heterocycles belongs to flavonoid family. The article intends to put forth the rational design and synthesis of a new series of aurones using 3’,5’-dibromo-2’,4’-dihydroxychalcones and copper bromide in presence of DMF-water mixture (8:2, v/v) for the first time. Preliminary bioassay shows that most of compounds have good trypanocidal activity against Trypanosoma cruzi at 10 μg/mL. Few compounds are equally potent to the standard drugs Benznidazole and Nifurtimox. The structures of the newly synthesized products 2a-n were established by elemental analysis, FTIR, 1H NMR, 13C NMR and mass spectroscopic studies.
Two special organelles found in Trypanosoma cruzi
Anais da Academia Brasileira de Ciências , 2000, DOI: 10.1590/S0001-37652000000300016
Abstract: we review here two unique organelles from trypanosoma cruzi. one of them is the acidocalcisome, cytoplasmic vacuoles containing a very high ca2+ concentration and a ca2+ - h+ translocating atpase activity, present in all trypanosomatids. the other organelle is the reservosome, site of accumulation of endocytosed macromolecules, very rich in cysteine proteinase, that is present only in epimastigote forms of trypanosomes belonging to the schyzotrypanum sub-genus.
In vitro activity of Etanidazole against the protozoan parasite Trypanosoma cruzi
Petray, Patricia B;Morilla, María J;Corral, Ricardo S;Romero, Eder L;
Memórias do Instituto Oswaldo Cruz , 2004, DOI: 10.1590/S0074-02762004000200021
Abstract: we investigated the in vitro action of an hydrosoluble 2-nitroimidazole, etanidazole (ezl), against trypanosoma cruzi, the etiologic agent of chagas disease. ezl displayed lethal activity against isolated trypomastigotes as well as amastigotes of t. cruzi (ra strain) growing in vero cells or j774 macrophages, without affecting host cell viability. although not completely equivalent to benznidazole (bzl), the reference drug for chagas chemotherapy, ezl takes advantage in exertingits anti-t. cruzi activity for longer periods without serious toxic side effects, as those recorded in bzl-treated patients. our present results encourage further experiments to study in depth the trypanocidal properties of this drug already licensed for use in human cancers.
Swimming against the current: genetic vaccination against Trypanosoma cruzi infection in mice
Rodrigues, Mauricio M;Alencar, Bruna C de;Claser, Carla;Tzelepis, Fanny;Silveira, Eduardo L;Haolla, Filipe A;Dominguez, Mariana R;Vasconcelos, José Ronnie;
Memórias do Instituto Oswaldo Cruz , 2009, DOI: 10.1590/S0074-02762009000900037
Abstract: vaccines have had an unquestionable impact on public health during the last century. the most likely reason for the success of vaccines is the robust protective properties of specific antibodies. however, antibodies exert a strong selective pressure and many microorganisms, such as the obligatory intracellular parasite trypanosoma cruzi, have been selected to survive in their presence. although the host develops a strong immune response to t. cruzi, they do not clear the infection and instead progress to the chronic phase of the disease. parasite persistence during the chronic phase of infection is now considered the main factor contributing to the chronic symptoms of the disease. based on this finding, containment of parasite growth and survival may be one method to avoid the immunopathology of the chronic phase. in this context, vaccinologists have looked over the past 20 years for other immune effector mechanisms that could eliminate these antibody-resistant pathogens. we and others have tested the hypothesis that non-antibody-mediated cellular immune responses (cd4+ th1 and cd8+ tc1 cells) to specific parasite antigens/genes expressed by t. cruzi could indeed be used for the purpose of vaccination. this hypothesis was confirmed in different mouse models, indicating a possible path for vaccine development.
Biological characterization of Trypanosoma cruzi strains
Martínez-Díaz, Rafael A;Escario, José A;Nogal-Ruiz, Juan J;Gómez-Barrio, Alicia;
Memórias do Instituto Oswaldo Cruz , 2001, DOI: 10.1590/S0074-02762001000100006
Abstract: biological parameters of five trypanosoma cruzi strains from different sources were determined in order to know the laboratory behaviour of natural populations. the parameters evaluated were growth kinetics of epimastigotes, differentiation into metacyclic forms, infectivity in mammalian cells grown in vitro and parasite susceptibility to nifurtimox, benznidazole and gentian violet. differences in transformation to metacyclic, in the percentage of infected cells as well as in the number of amastigotes per cell were observed among the strains. regarding to pharmacological assays, y strain was the most sensitive to the three assayed compounds. these data demonstrate the heterogeneity of natural populations of t. cruzi, the only responsible of infection in humans.
Immunopathology of Chagas disease
Andrade, Zilton A;
Memórias do Instituto Oswaldo Cruz , 1999, DOI: 10.1590/S0074-02761999000700007
Abstract: the main clinical forms of chagas disease (acute, indeterminate and chronic cardiac) present strong evidences for the participation of the immune system on pathogenesis. although parasite multiplication is evident during acute infection, the intense acute myocarditis of this phase exhibits clear ultrastructural signs of cell-mediated immune damage, inflicted to parasitized and non-parasitized myocardiocytes and to the endothelium of myocardial capillaries (microangiopathy). inflammation subsides almost completely when immunity decreases parasite load and suppressor factors modulate host reaction, but inflammation does not disappear when the disease enters the indeterminate phase. inflammation becomes mild and focal and undergoes cyclic changes leading to complete resolution. however, the process is maintained because the disappearance of old focal lesions is balanced by the upsurge of new ones. this equilibrium allows for prolonged host survival in the absence of symptoms or signs of disease. the chronic cardiac form is represented by a delayed-type, cell-mediated diffuse myocarditis, that probably ensues when the suppressive mechanisms, operative during the indeterminate phase, become defaulted. the mechanism responsible for the transition from the indeterminate to the cardiac form, is poorly understood.
Caracteriza??o biológica de clones das cepas Y, CL e MR de Trypanosoma cruzi em camundongos C3H isogênicos
Araújo, S. Marques de;Chiari, E.;
Memórias do Instituto Oswaldo Cruz , 1988, DOI: 10.1590/S0074-02761988000200005
Abstract: ten clones of trypanosoma cruzi isolated from y, cl and mr strains were studied. the infectivity of culture forms, parasitemia pattern, polymorphism and mortality were studied in c3h inbred mice. significant intra-group differences among y and cl clones were found. mr clones showed higher homogeneity. these data indicate that t. cruzi strains can show different degrees of heterogeneity. it is suggested that conditions used to maintain t. cruzi strains may resuly in a selective advantage for some subpopulations (clones) after many years laboratory maintenance.
Utilidad de una encuesta para identificar donantes de sangre de zonas no endémicas, potencialmente infectados con Trypanosoma cruzi
Parasitología al día , 1999, DOI: 10.4067/S0716-07201999000300012
Abstract: large numbers of immigrants from endemic areas for chagas' disease resided in maule region and transmission can occur by blood transfusion.is important evaluated the usefulness of a questionnaire for identifying trypanosoma cruzi infected blood donors in nonendemic area. in this work participate blood donors of 7 hospitals of the region. during the 6-month period, 1.581 blood donors were asked and their samples were analysed for t. cruzi antibodies.the effectiveness of the questionnaire was evaluated by comparing donor's answers about their risk for chagas' disease with the result of testing with an enzyme-linked immunosorbent assay. positives samples were confirm by: indirect immunofluorescence, and polymerase chain reaction. only one donor was positive to chagas' disease. this donors reported no risk factors. therefore blood donors seropositive for t. cruzi are presente in donors population of nonendemic area without the usual identifiable risk factors
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