ABSTRACT
BACKGROUND: Chagas' disease is an endemic tropical affliction found from southern United States to Argentina. The acute phase of this disease is difficult to study in man because the symptoms are non-specific and most cases require no medical assistance. Experimental models have been developed for sequential studies, and intense parasitism in all organs and tissues, including the pancreas, have been detected in the acute phase. PURPOSE: To evaluate the involvement of the pancreas in acute experimental Chagas' disease in a mouse model by histopathological characterization. CASUISTIC AND METHODS: Ten BALBc mice, about 20 g, injected i.p. with 100 000 forms of the Y strain of Trypanosoma cruzi were used. The animals were sacrificed after 14 days of infection. Fragments of pancreas were processed by conventional paraffin embedding and hematoxylin-eosin staining. RESULTS: Ruptured pseudocysts and release of parasites to the extracellular medium caused by necrosis of acinar and duct cells and foci of fat were the most striking histopathological features of acute Chagasic pancreatitis. CONCLUSION: Parasitism is the main cause of acute pancreatitis in Chagas' disease
Subject(s)
Animals , Mice , Chagas Disease , Pancreas , Pancreatitis , Acute Disease , Chagas Disease , Disease Models, Animal , Mice, Inbred BALB C , Pancreas , PancreatitisABSTRACT
Since 1958, we have studied experimental Chagas' disease (CD) by subcutaneous inoculation of 1,000 blood forms of Trypanosoma cruzi (Y strain) in Balb/C. mice. Evolution of parasitemia remained constant, beginning on the 5th and 6th day of the disease, increasing progressively, achieving a maximum on about the 30th day. After another month, only a few forms were present, and they disappeared from the circulation after the third month, as determined from direct examination of slides and the use of a Neubauer Counting Chamber. These events coincided with the appearance of amastigote nests in the tissues (especially the cardiac ones), starting the first week, and following the Gauss parasitemia curve, but they were not in parallel until the chronic stage. In 1997, we began to note the following changes: Parasites appeared in the circulation during the first week and disappeared starting on the 7th day, and there was a coincident absence of the amastigote nests in the tissues. A careful study verified that young forms in the evolutionary cycle of T. cruzi (epi + amastigotes) began to appear alongside the trypomastigotes in the circulation on the 5th and 7th post-inoculation day. At the same time, rounded, oval, and spindle shapes were seen circulating through the capillaries and sinusoids of the tissues, principally of the hematopoietic organs. Stasis occurs because the diameter of the circulating parasites is greater than the vessels, and this makes them more visible. Examination of the sternal bone marrow revealed young cells with elongated forms and others truncated in the shape of a "C" occupying the internal surface of the blood cells that had empty central portions (erythrocytes?). We hypothesize that there could be a loss of virulence or mutation of the Y strain of Trypanosoma cruzi
Subject(s)
Animals , Male , Mice , Life Cycle Stages/physiology , Trypanosoma cruzi/growth & development , Mice, Inbred BALB C/parasitology , Parasitemia/parasitology , Time Factors , Trypanosoma cruzi/pathogenicitySubject(s)
Animals , Mice , Acute-Phase Reaction , Chagas Disease/pathology , Edema/etiology , Cytokines/adverse effects , Cytokines/pharmacology , MiceABSTRACT
Os mega-orgaos na Doenca de Chagas sao bem conhecidos, especialmente os desenvolvidos no sistema digestivo. A infeccao aguda apresenta parasitismo de diversas celulas, tecidos e orgaos, dentre eles a bexiga urinaria. Camundongos Balb/c infectados com 100.000 formas sanguineas de cepa Y de T. cruzi mostraram intenso parasitismo de todas camadas da bexiga urinaria na fase aguda. Os parasitas foram encontrados na mucosa, submucosa, lamina propria, muscular, adventicia e tecido adiposo, alem das celulas descamadas para a luz do orgao...
Subject(s)
Animals , Mice , Chagas Disease/pathology , Urinary Bladder Diseases/parasitology , Trypanosoma cruzi/parasitology , Urinary Bladder Diseases/pathologyABSTRACT
Ciclosporina A e um agente imunossupressor de relevância clinica que possui também atividade antiparasitaria potente. Em transplantes de orgäo e enxertos de tecido, este agente e com frequência utilizado em conjunto com hidrocortisona. Assim, efeitos reciprocos destes imunossupressores foram estudados na esquistossomose mansoni experimental. Camundongos foram inoculados com cercarias de Schistosoma mansoni por via subcutanea, e animais parasitados que foram ou näo tratados com oxamniquine, foram tambm subsequentemente imunossuprimidos ou nao. Exacerbacoes da parasitemia e parasitismo potencialmente fatal foram observadas em animais imunossuprimidos, em contraste com animais controles, sugerindo que tambem em pacientes transplantados, a evolucao da esquistossomose seria igualmente adversa. Apesar do efeito imunomodelador predominante, esses agentes em conjunto apresentaram ainda moderada atividade antiparasitaria completando o efeito esquistossomicida de oxamniquine. Atividade esta favorável no tratamento da esquistossomose em transplantados
Subject(s)
Animals , Male , Rats , Immunosuppression Therapy/methods , Schistosoma mansoni/drug effects , Schistosomiasis mansoni/therapy , Cyclosporine , Cyclosporine/therapeutic use , Parasitic Diseases/therapy , Organ Transplantation , Oxamniquine/therapeutic use , Schistosomiasis mansoni/parasitologyABSTRACT
Com a finalidade de estudar a acao das drogas imunossupressoras nas parasitoses, estudamos a Cyclosporina A e Cortisona na toxoplasmose experimental, utilizando uma cepa altamente virulenta do Toxoplasma gondii (cepa RH). Os animais foram divididos em dois lotes: controle e imunodeprimidos, sendo avaliados pela pesquisa da parasitemia e parasitismo do exsudato peritoneal, e parasitismo do coracao, figado, baco, pancreas, intestino, rim, supra renal, cerebro, cerebelo, medula espinhal e globo ocular sendo sacrificados diariamente dois animais de cada grupo. O parasitismo do exsudato peritoneal foi dez vezes maior que a parasitemia do segundo dia, foram encontradas manchas avermelhadas e do quarto dia, necroses focais com areas de amolecimento e liquefacao da massa encefalica salpicadas no tecido nervoso...
Subject(s)
Animals , Rats , Immunosuppression Therapy/adverse effects , Toxoplasmosis/complications , Transplants/parasitology , Toxoplasmosis/pathologyABSTRACT
Com a finalidade de estudar a patogenia da miocardite chagasica , foram inoculados camundongos brancos com a cepa Y do Trypanosoma cruzi. Os animais, após o controle da parasitemia, foram sacrificados: a)para a fase aguda (primeiros 30 dias), cinco animais diariamente; b)sub-aguda (do trigesimo dia e nonagesimo dia), cinco animais semanalmente e c)crônica, os sobreviventes com 365 dias após inoculacao. A parasitemia surgiu no sexto dia e aumentou progressivamente até atingir o seu nível máximo na terceira ou quarta semana, decrescendo a seguir ate o trigésimo dia, desaparecendo do sangue circulante após o octogesimo sétimo dia. O parasitismo acompanhou a parasitemia, porém sem relaçäo quantitativa...
Subject(s)
Animals , Male , Mice , Chagas Disease/etiology , Chagas Cardiomyopathy/pathology , Chagas Disease/parasitology , Myocarditis/parasitologySubject(s)
Animals , Rats , Mice , Pulmonary Edema/pathology , Respiratory Insufficiency/physiopathology , Iatrogenic DiseaseABSTRACT
Three strains of Trypanosoma cruzi were isolated from Chagas' disease patients transplanted for heart failure, after cardiac transplantation, and were studied in an experimental model of Chagas' disease, in mice, with evaluation of parasitic load, mortality and extension of inflammatory infiltrates in the heart. These parameters were compared with the standard strain Y. The strains had differences in the studied parameters, but there was no clear relationship between those and post-transplant evolution of the patients. Probably the clinical response is multifactorial and derives only in part from biological characteristics of the infecting T. cruzi strain, as measured in our model.
Subject(s)
Humans , Animals , Male , Female , Adolescent , Adult , Mice , Heart Transplantation , Trypanosoma cruzi/isolation & purification , Disease Models, Animal , Feces/parasitology , Mice, Inbred BALB C , Chagas Cardiomyopathy/surgery , Chagas Cardiomyopathy/parasitology , Chagas Cardiomyopathy/pathology , Parasitemia/parasitology , Parasitemia/pathology , Postoperative Period , Time Factors , Trypanosoma cruzi/pathogenicityABSTRACT
Com o intuito de estudar os fenomenos naturais de defesa contra as hemorragias traumaticas, foram estudados 20 camundongos examinando-se histologicamente algumas de suas grandes veias em caso de sangria, sangria+hemodiluicao e controles, apos fixacao em formol...
Subject(s)
Animals , Female , Mice , Shock/chemically induced , Isotonic Solutions/toxicity , Mice, Inbred BALB C/anatomy & histology , Shock/bloodABSTRACT
Tres cepas do Trypanosoma cruzi foram isoladas de pacientes com doenca de Chagas cronica, receptores de coracao por meio de transplante. Houve a caracterizacao dela atraves de modelo experimental baseado no emprego de camundongos, com avaliacao de parasitismo, mortalidade e intensidade da inflamacao no coracao, alem de analise do grau de parasitismo nesse orgao. Como controle, teve lugar comparacao com o comportamento da ja bem conhecida cepa Y. Ficaram caracterizadas atuacoes diferentes das cepas, ao serem valorizados os parametros citados, sem correlacao rigorosa com as evolucoes pos-transplantes, que sofrem a influencia de varios fatores, entre os quais podem estar particularidades vinculadas ao parasitismo.
Subject(s)
Humans , Male , Adolescent , Adult , Chagas Disease/parasitology , Heart Transplantation/immunology , Trypanosoma cruzi/isolation & purification , Chagas Disease/immunology , Trypanosoma cruzi/analysisABSTRACT
Relato de um estudo experimental realizado em camundongos brancos infectados com Trypanosoma cruzi. Foram estudados o trânsito intestinal e morfologia do cólon por meio de raio-X. Na fase subaguda, o trânsito intestinal apresentou-se normal. Nas fases aguda e crônica, havia entretanto, um retardo no tempo de evacuaçäo. Num dos 12 animais, o enema opaco revelou a presença de megacolon
Subject(s)
Animals , Mice , Chagas Disease/physiopathology , Gastrointestinal Transit , Chagas Disease , Enema , Megacolon/physiopathology , Mice, Inbred BALB CABSTRACT
En virtude de informacoes de que o fluconazol pode coibir a infeccao devida ao Trypanosoma cruzi, efetuamos investigacao experimental a respeito, utilizando camundongos agudamente infectados e esquema terapeutico baseado na administracao de 200 mg/kg/dia da referida droga, durante um mes. Parasitemia, hemocultura, subinoculacao e exame histologico serviram como parametros para avaliar a eventual atividade curativa do medicamento em questao. Os resultados obtidos nao confirmaram a propriedade aventada, mas e conveniente estimular novos estudos sobre o assunto, envolvendo o imidazoico que usamos, alem de outros.
Subject(s)
Mice , Animals , Female , Chagas Disease/therapy , Fluconazole/therapeutic use , Acute Disease , Fluconazole/administration & dosage , Drug Evaluation, PreclinicalABSTRACT
Other authors have demonstrated that itraconazole has antiparasitic activity against Trypanosoma cruzi both in vitro and in animal acute infection. Because of these observations, we decided to evaluate the chronic phase of this protozoal disease, since it is the most important form under a clinical and assistential point of view. We studied an infected mouse model as well as human cases of Chagas' disease. One hundred mg/kg/day by gastric tube, and 100 or 200 mg/day orally were given, respectively, during three months, without showing any beneficial effect, at least with the adopted methods.