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Biomedical subjects

A Szarfman

Publications and source records attributed to A Szarfman.

At least 37 records · Page 2Linked to original sources
PubMed1981

Tissue-reacting immunoglobulins in patients with different clinical forms of Chagas' disease.

Antibodies against endocardium, blood vessels, interstitium, and plasma membrane of skeletal and heart muscle cells (EVI), as well as antibodies against structures from peripheral nerve (PN), were studied in serum samples from 27 individuals with negative Trypanosoma cruzi serology and 102 seropositive individuals with or without Chagas' disease from the State of Goiás, Brazil. Although significantly higher titers of EVI and PN antibodies were found in some of the seropositive individuals their presence was not correlated with the clinical symptoms and signs which characterize the chronic stage of the disease, nor with the severity of the disease.

Antibodies↗
PubMed1979

Antibody-induced capping of the intracellular stage of Trypanosoma cruzi.

Intracellular-stage Trypanosoma cruzi were isolated from infected mice. The effect of specific human antibodies on the membrane surface antigens was studied in vitro, using the immunofluorescent technique. The immune serum induced the aggregation of surface antigens, forming polar caps on the amastigotes.

Animals↗
PubMed1979

Circulating antibodies to peripheral nerve in American trypanosomiasis (Chagas' disease).

An antibody reacting with Schwann sheaths of myelinated somatic and unmyelinated autonomic peripheral nerve was found in sixty-one out of seventy-one chronic, and nine out of ten acute, Chagas' disease sera. Indirect immunofluorescence (IFL) was carried out on rat, mouse and human somatic nerves and rat sympathetic nerves with initial serum dilutions of 1 : 10, and the staining reached a final titre of 1 : 320 in some cases. The antibodies fixed complement and were absorbed out by lyophilized epimastigotes of T. cruzi. Lipid extraction of the tissue sections enhanced the staining of myelinated nerve, whereas unfixed unmyelinated sympathetic nerve was strongly reactive. Central nervous tissue did not display any positive staining on neurons, glial cells or periaxonal sheaths. Furthermore, by using a double-labelled IFL technique, it was possible to show that a rabbit antiserum raised against guinea-pig spinal cord and the chagasic anti-nerve antibodies reacted with different structures in the rat sciatic nerve. These findings suggest that the reactive antigen(s) could be located on Schwann cells. The majority, but not all, of the chagasic individuals with anti-nerve antibodies also showed the sarcolemmal and endothelial staining (EVI) previously described in Chagas' disease. The possible recognition of Schwann cell antigens by circulating antibodies in Chagas' disease could be relevant, since an autonomic denervation has been postulated as a pathogenic mechanism of cardiomyopathy and megaviscera in this condition.

Animals↗
PubMed1978

Immunofluorescent vascular pattern due to EVI antibody of Chagas' disease. Its diagnostic value.

One hundred fifty-six of 1,250 sera from patients with presumed connective tissue and related diseases showed vascular staining on mouse liver cryostat sections when they were routinely checked for antinuclear factor by the indirect immunofluorescence test. In a third of the cases, the vascular immunofluorescent pattern was given by the EVI antibody reacting with the plasma membrane of striated muscle fibers and endothelial cells, as has been recently described to occur in Chagas' disease. This led to the detection of previously unsuspected Trypanosoma cruzi infection in 67.8% of the serum samples in which the EVI antibody was detected after observation of a positive vascular pattern with mouse liver cryostat sections. On the other hand, no significant relationship between Chagas infection and sera with other anti-striated-muscle immunofluorescent patterns that also showed a vascular staining on mouse liver cryostat sections was established. Consideration of the vascular pattern observed with the EVI antibody on mouse liver cryostat sections can be helpful in detection of previously ignored T. cruzi infection in patients who have connective-tissue diseases and related conditions. This is of interest in view of the fact that anergic immunodepressive therapy, often used in these patients, significantly alters the host-parasite relationship and may lead to severe dissemination of the parasite.

Antibodies↗
PubMed1978

Tissue-reacting antibodies (EVI antibodies) in nifurtimox-treated patients with Chagas's disease.

Antibodies reacting against endothelial cells, vascular structures, and heart and skeletal muscle cells (EVI antibodies) were studied in 10 patients (one to 14 years of age) treated with Nifurtimox. The patients were observed for several months to two years after the onset of symptoms of acute infection with Trypanosoma cruzi. Although these 10 patients were selected because after treatment their sera became negative for antibodies to T. cruzi as detected by the immunofluorescence test, sera from six patients remained positive for EVI antibodies. It is suggested that EVI antibodies may be self-perpetuated in the absence of infection. Further studies are needed to determine the pathogenic significance of EVI antibodies.

Adolescent↗
PubMed1978

Immunoglobulin concentration in treated human acute Chagas disease. A follow-up study.

Immunoglobulin M, G, and A concentrations were studied by radial immunodiffusion technique in 16 individuals (two were 16 and 14 yr of age, respectively, while the remaining 14 uere 15 yr of age or less) with acute Trypanosoma cruzi infection. Serum samples were obtained from these patients beginning with the onset of symptoms and continuing until several months after treatment with nifurtimox was completed. Soon after infection the concentration of IgM was higher than the average found in healthy children. Some of the samples also had higher values than those found in children with other acute infections. At this time isolated increases in IgG and/or IgA concentrations were also found in T. cruzi-infected patients. Immunoglobulin concentrations had usually returned to normal when treatment with nifurtimox was completed, both in the patients with negative serology and in those who remained positive. However, some of the sera showed isolated higher IgM, IgG, and/or IgA values than those found in healthy controls.

Adolescent↗
PubMed1978

Tissue reacting antibodies in a rhesus monkey with long-term Trypanosoma cruzi infection.

Immunoglobulins (Igs) reacting against endothelial and vascular structures and striated muscle cells as well as against cells from a peripheral nerve were detected by indirect immunofluorescent test (IIF) in a rhesus monkey infected for 29 yr with Trypanosoma cruzi. Anti-T. cruzi antibodies in this monkey showed a titer of 1:128 in the IIF test and the direct agglutination test. Tissue-reacting Igs were bound in vivo to the tissues, as was established by direct treatment of a biopsy of the deltoid muscle with Ig-labeled antisera. Electron microscopy of this tissue showed that Igs reacted with the plasma membrane of the muscle cells. Neither tissue-reacting Igs nor specific antibodies were detected in three uninfected adult monkeys.

Animals↗
PubMed1975

Investigation of the EVI antibody in parasitic diseases other than American trypanosomiasis. An anti-skeletal muscle antibody in leishmaniasis.

The specificity of a circulating antibody observed in American trypanosomiasis and reacting with endocardium, blood vessels, and the interstitium of striated muscle (EVI factor) was evaluated in the indirect fluorescent antibody test with 60 sera from patients with malaria, leishmaniasis, echinococcosis, amebiasis, African trypanosomiasis, toxoplasmosis, and trichinosis, collected from areas where Chagas' disease is not endemic. Two sera, 1 from a patient with Plasmodium falciparum malaria and 1 from a patient with a relapse pretreatment post kala-azar dermal leishmaniasis, were positive for the EVI factor. In the leishmaniasis group, 3 of 8 sera reacted with 0ovine, murine, and human skeletal muscle. In this reaction, which differs from the EVI test, the sarcolemma and the intracellular structures were stained.

Animals↗