Biomedical subjects
Publications and source records attributed to M Sadigursky.
A liquid medium without blood or serum was developed for cultivation of hemoflagellates. To a basic LIT medium containing liver infusion broth and tryptose, a mixture of RPMI 1640 and Medium 199 was added. This combination permitted high parasite yields useful for biochemical and immunological studies.
An electrocardiographic study was performed on 26 AKR and 32 A/J inbred mice and on 100 Swiss outbred mice, chronically infected with different strains of T. cruzi, characterized as Types I, II and III. The incidence of electrocardiographic alterations in AKR mice was of 87.0%, 80.0% and 83.3% respectively for infection with the Type I, Type II and Type III strains of T. cruzi. In A/J mice the incidence of electrocardiographic alterations was 100% in the infection with the Type I and Type III strains and 26.1% with the Type II strain of T. cruzi. In Swiss mice the electrocardiographic alterations occurred in 53.5% of the mice infected with the Type II strain and in 71.4% of those infected with the Type III strain of T. cruzi. The most frequent electrocardiographic alterations in chronically infected mice, independently of mouse or T. cruzi strain, were first degree AV block, intraventricular conduction abnormalities, sinus tachycardia and bradycardia. The predominant alterations caused by each of the T. cruzi strains varied according to mouse strain. In A/J mice, the electrocardiographic alterations were more frequent in those animals infected with Type I and III strains of T. cruzi and in Swiss mice the alterations were more frequent in those infected with the Type III strain. The results presented in this study demonstrate that the murine model is suitable for electrocardiographic studies related to the heart lesions that occur in Chagas' disease.
Highly resistant (C57BL/10) and intermediately resistant (DBA/2) mice were infected subcutaneously with Leishmania mexicana amazonensis in a hind footpad subsequent to removal of the draining popliteal node. These mice developed greatly exacerbated Leishmania infections as compared to sham-operated controls or to mice infected in the contralateral footpad. The majority of mice in which the draining lymph nodes were removed prior to infection developed metastases, lost their delayed hypersensitivity responses to Leishmania, and some died. Significantly fewer metastases and no deaths were observed in the control groups. The results emphasize the importance of lymphatic control of Leishmania m. amazonensis infection in relatively resistant mouse strains.
The sera from patients with primary heart and skeletal muscle diseases, hospitalized patients without intrinsic muscle disease from an area endemic for Trypanosoma cruzi infections, and normal subjects (N = 693) were studied for the presence of immunoglobulin G (IgG) antisarcolemma activity using serologic methods. The prevalence of elevated serum IgG antisarcolemma activity from patients with chronic Chagas' cardiomyopathy, idiopathic cardiomyopathy, polymyositis, and Duchenne muscular dystrophy was 58.9 +/- 10.4% (N = 101) (P less than 0.001 when compared to normal subjects). Two of twelve (16.7%) patients with acute T. cruzi infection and parasitemia developed elevated antisarcolemma titers, and 9/46 (19.6%) patients with chronic T. cruzi infection without evidence of cardiomyopathy yielded high antisarcolemma titers. On the other hand, patients with chronic T. cruzi infection with advanced cardiomyopathy yielded high antisarcolemma titers in 35/74 (47.3%) (P less than 0.001 when compared to normal subjects). Radioimmunoprecipitation showed a circulating antibody to a 25-kDa T. cruzi polypeptide (P25) in 16/17 (94.1%) patients with advanced cardiomyopathy and T. cruzi infection. No such antibody was shown in 12 asymptomatic subjects with chronic T. cruzi infection.
Differentiation between a non-infective and an infective Leishmania promastigote population was demonstrated. Promastigotes in the stationary phase (day 5) were found to be highly infective in vitro to BALB/c mouse peritoneal macrophages, compared with those of the logarithmic phase (day 3). The infective promastigotes showed surface antigenic determinants different from non-infective ones. Polyclonal anti-3 day and anti-5 day antibodies were bound specifically to the surface of corresponding promastigotes in both SRIA and IFAT; no strong cross-reactions were observed otherwise. Also, polyclonal anti-5 day but not anti-3 day antibodies recognized efficiently the antigenic molecules on the surface of late stage (day 7) sandfly promastigotes. This clearly indicates the appearance of new antigenic molecules on the surface of infective promastigote forms. Intracellular multiplication of Leishmania was significantly inhibited by anti-5 day antibodies compared with anti-3 day antibodies. The presence of new surface molecules on late stage promastigotes may contribute to Leishmania infectivity.
Sodium dodecyl sulfate-polyacrylamide gel electrophoresis patterns of proteins and externally exposed labeled surface constituents were analyzed in promastigotes of three etiological agents of kala azar (Leishmania donovani, HS70 strain from India; L. chagasi, Imperatriz strain from Brazil; L. infantum, ITMPA K263 strain from Morocco and MO strain from France). Coomassie blue-stained gels showed similar protein patterns for L. donovani and L. chagasi and a more distinct one for L. infantum. Surface radioiodination with two different methods, lactoperoxidase and IODO-GEN, gave identical autoradiographic patterns for each parasite. Four major labeled proteins with apparent Mr values of 65,000, 60,000, 50,000, and 26,000 were detected in both L. chagasi and L. donovani. However, the radioiodinated polypeptide pattern of L. infantum only showed two major bands with an apparent Mr of 62,000 and a doublet of 26,000 to 23,000. Immunoprecipitation of detergent extracts of labeled promastigote subspecies with immune sera from rabbits immunized with either L. chagasi or L. infantum and from patients and mice infected with these two parasites, as well as with a monoclonal antibody against the surface of L. donovani promastigotes, demonstrated that the surface antigenic expression of L. infantum is different from that noticed in the two other subspecies, which are similar. Immunofluorescence experiments with some of these antibodies confirmed these results. The present findings should be considered in taxonomic and immunological studies in visceral leishmaniasis.
The consequences of acute inflammatory damage and chronic repair in the conducting system of the canine heart were observed after experimental Trypanosoma cruzi infection of young dogs. Acute infection lasted for 18-25 days and caused hyaline and lytic necrosis of the atrio-ventricular conducting fibres, the sinus node and the neurons in the cardiac para-sympathetic ganglia. Dogs that survived acute disease were examined after periods from 8 months to 3 years. Three main types of healing were found in the conducting system: fibrosis (diffuse and/or focal), sclero-atrophy and fatty infiltration. No signs of active chronic inflammation were present, although small focal residual accumulations of mononuclear cells were present in some animals. No evident electrocardiographic alterations were elicited by the presence of such cicatricial lesions. The animal model appears worthwhile for the study of the healing process in conducting tissue of the heart and for the better understanding of the asymptomatic phase of T. cruzi infection in man.
Relatively susceptible BALB/c and relatively resistant A/J mice were infected subcutaneously in the right hind footpad with promastigotes of Leishmania mexicana amazonensis. A large localized lesion developed within 2 months after infection in the BALB/c mice, while A/J mice exhibited a small discrete fibrotic nodule. Sequential immunologic and histologic examination demonstrated that BALB/c mice developed a nodular foam-cell type of lesion and progressive depression of a delayed-type hypersensitivity (DTH) response to leishmania antigen, while the A/J mice had a mixed cellular fibrosing and encapsulating reaction and developed and maintained positive DTH responses to leishmania antigen. Anti-leishmania antibody responses were positive at similar levels in both strains. The lesions in BALB/c mice were found in bone marrow, tendon, skin appendages, and regional lymph nodes, with a tendency toward cutaneous metastases. Lesions in A/J mice remained localized. Fibrosis, focal fibrinoid necrosis, and lymphocytic and macrophagic infiltration were the outstanding features. Light and transmission electron microscopic studies indicated that no outstanding destruction of leishmanias seemed to occur within macrophages of either mouse strain. In the more resistant A/J mice, however, parasitized macrophages were frequently necrotic, and degenerating leishmanias were often seen free in the interstitial tissue. These observations help the interpretation of the histologic features, as well as the pathogenesis, of cutaneous and mucocutaneous leishmaniasis in man.
We have previously shown that Trypanosoma cruzi shares antigenic determinants with preparations of the calcium-sequestering adenosine triphosphatase of sarcoplasmic reticulum. The cross-reacting antigen (SRA) is also apparently present on the sarcolemma of cardiac myofibers. Using highly specific reference antisera to either the small membranes of T. cruzi or to a tryptic fragment of striated muscle SRA, it was shown that SRA is present in the striated muscle of animals representative of the evolutionary scale ranging from nonhuman primate to fish. The small membranes of nine different T. cruzi strains isolated from widely divergent areas of the American continents also reacted with the reference antisera. This indicates that SRA is present in these T. cruzi strains and may be prevalent among all T. cruzi strains. The shared T. cruzi-striated muscle antigen, SRA, may be a heteroantigen present in all T. cruzi strains and in the striated muscle of all classes of animals. Immunization of rabbits (three of five) or chickens (five pairs of five pairs) with striated muscle membrane preparations of different classes of animals, particularly those of nonhuman primate, chicken, and turtle, gave rise to IgG anti-allogeneic striated muscle antibody activity. Immunization of rabbits (four of nine) and chickens (five pairs of six pairs) with the small membranes of different T. cruzi strains also produced IgG anti-allogeneic striated muscle. These data indicate that T. cruzi shares cross-immunogenicity with striated muscle SRA. Since SRA is apparently present on the sarcolemma of cardiac myofibers, it may be implicated in the immunopathogenesis of Chagas' disease.
We report the fifth case of subcutaneous zygomycosis caused by Basidiobolus haptosporus in Brazil. The lesion appeared as a tumor in the right mandibular area mimicking Burkitt's lymphoma of the jaw. In this patient evaluation of cellular immunity with the lymphoblastic transformation test yielded normal results.
Necropsy was performed in 32 cases of schistosomal cor pulmonale, and the lungs were studied by means of conventional histologic techniques, by serial sectioning, and by the method of plastic vascular casting. Fibrin deposition and marked endothelial cell hyperplasia were the main early changes evoked by schistosome eggs within small arteries and arterioles. A complex fibrin thrombus organization and revascularization, followed by congestion and dilatation of focal blood vessels, resulted in plexiform lesions. Vascular casts showed them to be purely arterial, to have a glomeruloid appearance, and to originate laterally or terminally in small arteries.
The results reported here show that a clone of a South American Trypanosoma cruzi human isolate has an epitope antigenically related to sarcoplasmic reticulum adenosine triphosphatase preparations (SRA), an enzyme implicated in the contraction-relaxation cycle of striated muscle. The antigenic determinant of T. cruzi, which is cross-reactive with SRA, is located in the interior of the parasite. No surface cross-reaction was detected with intact, freely swimming flagellates. Indeed, the degree of cross-reactivity was increased when T. cruzi microsomes were trypsinized, probably resulting in further exposure of the normally internal cross-reactive epitope.
Pathology of the chronic latent phase of Chagas' disease is poorly understood. In our experiment, nine dogs were inoculated with Trypanosoma cruzi and acute disease developed within 15 to 25 days, followed by a chronic asymptomatic period that varied from eight months to three years, at which time the animals were killed. Although ECG changes were minimal, all animals showed a mild focal chronic myocarditis, with a few microscopic foci of fibrosis. Focal or diffuse fibrosis, scleroatrophy, and fatty replacement were present in various parts of the conducting system, especially in the atrioventricular node, the distal portion of His' main bundle, and the initial portion of the right bundle. These lesions were considered to be sequelae from inflammation and necrosis during the acute phase of the infection. In addition to characterizing the lesions of the chronic indeterminate phase of Chagas' disease in the canine model, the present findings suggest that the lesions may be responsible for ECG changes that may appear in subjects with otherwise asymptomatic T cruzi infection.
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In order to study the effect of combined treatment of Trypanosoma cruzi infection with a nitrofuranic drug and a corticoid, 27 dogs from three different litters infected with T. cruzi (12 SF strain) were randomly litter-paired in three experimental groups: animals infected and not treated; infected and treated with Bay 2502 (2-methyl-4-[5'nitrofurfurylideneamino]-tetrahydro-4H-1,4-thiazine-1,1-dioxine) (nifurtimox); infected and treated with nifurtimox plus betamethasone. While an enhanced myocarditis appeared in the animals treated with a nitrofuranic drug alone, inflammation was almost abolished when corticoid treatment was added. Both groups showed considerable intracellular parasite destruction. These changes were monitored by serial electrocardiograms and a final histopathologic study which included an investigation of the changes in the conducting tissue by serial sectioning. The survival period was prolonged in animals treated with the combination of the nitrofuranic drug and corticoid, and only in this group did some of the animals reach the chronic phase of the infection. Thus, the association of a nitrofuranic drug with a corticoid in the treatment of acute Chagas' disease produced parasite destruction and inhibited the inflammatory responses that are enhanced by such destruction
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