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E R Lopes

Publications and source records attributed to E R Lopes.

At least 19 recordsLinked to original sources
PubMed2001

Neuron count reevaluation in the myenteric plexus of chagasic megacolon after morphometric neuron analysis.

This study was made with the objective of reevaluating the colon denervation in chronic Chagas' disease. The diameters of neuron perikaryons of the myenteric plexus were measured on paraffin sections in a ring from the sigmoid in Chagas' disease patients, 17 with and 10 without megacolon and in 10 non-chagasic controls. All neurons were counted in ten en-echelon sections. Neuron hypertrophy only occurred in the group with megacolon, and the average increase in diameter was 69.3%. This could generate an error factor in the neuron count by increasing the probability of neurons being seen in a greater number of histological sections. The original result of the neuron count gave medians of 1264, 1961, and 2665 in the groups of chagasic patients with megacolon, without megacolon, and in the control, respectively. The denervation was greater than 55% in only seven megacolon cases (41.2%). After applying a correction factor, the median in the group with megacolon was 746, and the denervation was greater than 55% in 13 cases (76.5%). This occurrence demonstrates the need to apply a correction factor when the neuron count in chagasic megacolon is being evaluated and in the other pathologies where neuron hypertrophy may be found.

Adult↗
PubMed2001

Morphometry of submucous and myenteric esophagic plexus of dogs experimentally reinfected with Trypanosoma cruzi.

We carried out a morphometric study of the esophagus of cross-bred dogs experimentally infected or consecutively reinfected with Trypanosoma cruzi 147 and SC-1 strains, in order to verify denervation and/or neuronal hypertrophy in the intramural plexus. The animals were sacrificed in the chronic stage, 38 months after the initial infection. Neither nests of amastigotes, nor myositis or ganglionitis, were observed in all third inferior portions of esophageal rings analyzed. No nerve cell was identified in the submucous of this organ. There was no significant difference (p>0.05) between the number, maximum diameter, perimeter, or area and volume of the nerve cells of the myenteric plexus of infected and/or reinfected dogs and of the non-infected ones. In view of these results we may conclude that the 147 and SC-1 strains have little neurotropism and do not determine denervation and/or hypertrophy in the intramural esophageal plexuses in the animals studied, independent of the reinfections.

Animals↗
PubMed2001

A study of experimental reinfection by Trypanosoma cruzi in dogs.

The role of reinfection in the evolution of Chagas' disease was evaluated in dogs alternately infected with the 147 and SC-1 strains of Trypanosoma cruzi. A parasitologic, serologic, clinical, and electrocardiographic follow-up was carried out on the infected and noninfected dogs. The dogs were reinfected five times over a period of 38 months. No deaths were observed during the experiment. They presented a brief oligosymptomatic acute phase. The level of parasitemia decreased progressively with the number of reinfections. Bloodstream parasites were not detectable after the fifth reinfection. All parasite samples isolated during the follow-up were zymodeme B, corresponding to strain 147, irrespective of the strain with which the dogs were first infected and of the triatomine species used for isolation. Conversely, amplification by the polymerase chain reaction of a segment of the T. cruzi mini-exon gene showed the simultaneous presence of both strains in three of the eight reinfected animals. Antibody titers were greater among the dogs successively infected than those infected only once. Neither amastigotes nor T. cruzi DNA were detected in the tissues of the infected dogs. Alterations related to Chagas' disease were identified only in the heart and consisted of chronic focal and discrete myocarditis, compatible with the indeterminate form of Chagas' disease. All infected dogs developed this form of the disease, which was independent of the number of infections.

Animals↗
PubMed1999

Imaging Trypanosoma cruzi within tissues from chagasic patients using confocal microscopy with monoclonal antibodies.

Confocal fluorescence microscopy combined with differential interference contrast imaging of tissues from chagasic patients enabled the unequivocal identification of the parasite Trypanosoma cruzi. Using different monoclonal antibodies that indicate the parasite form and replication stage in conjunction with DNA labelling, specimens derived from distinct clinical forms of the disease were examined. Intracellular amastigote forms of the parasite were clearly detected in heart, brain, skin, lung, and kidney. Dividing amastigotes as well as trypomastigote forms were recognized in samples obtained from patients undergoing either acute-phase or some form of reactivation caused by immunosuppression.

Adult↗
PubMed1998

Chagasic meningoencephalitis in the immunodeficient.

Based on their own experience and on the literature, the authors compare the brain pathology due to HIV+ associated Trypanosoma cruzi reactivated infection to that described for the natural history of the Chagas' disease (CD). The peculiar focal necrotizing chagasic meningoencephalitis (MECNF) which appears only in immunedeficient chagasics, especially when the deficiency is due HIV is a safe criterion for reactivation of CD. MECNF morphologic findings are unlike to those found either for some cases of acute phase CD or for chronic nervous form of CD.

AIDS-Related Opportunistic Infections↗
PubMed1995

Second recorded case of human infection by Echinococcus oligarthrus.

The paper reviews a previously published case of hydatid disease in the human heart of a Brazilian person who died of tetanus. Based on present knowledge about the distinguishing characteristics of Echinococcus granulosus, E. vogeli, and E. oligarthrus, it was recognized that the infection was due to E. oligarthrus, mainly based the morphologic features of the hooklets of the protoscolex. This is the second human infection due to E. oligarthrus and the first showing wall features of cysts. Therefore, some human infections of polycystic hydatid disease observed outside the range of the bush dog, the only definitive host of E. vogeli (Panama to Northern Argentina), may be due to E. oligarthrus rather than to E. vogeli.

Aged↗
PubMed1995

[Coronary arteriosclerosis and myocardial infarction in chronic Chagas' disease].

PURPOSE: To evaluate both the frequency of myocardial infarction and coronary atherosclerosis as well as the pathology of the later in necropsied chronic chagasic individuals. METHODS: Systematized gross and light microscopy were performed in hearts, especially at the three main coronary arteries. Eighty-nine hearts were studied, 35 chronic chagasics and 54 nonchagasics, all from males. Statistical tests were used for frequency analysis. RESULTS: Myocardial infarction occurred in 8.6% chagasics and in 7.4% nonchagasics. Coronary atherosclerosis was detected in 71.4% of chagasics and in 74.1% of nonchagasics. Its morphology was similar for both groups and indistinguishable from the classical descriptions of atherosclerosis. There were no cases showing lesions compatible with accelerated coronary atherosclerosis. CONCLUSION: The frequency of myocardial infarction and coronary atherosclerosis was the same for both chagasics and nonchagasic individuals. The morphological findings for the studied arteriopathy were identical for the two considered groups. However, it seems that the frequency of myocardial infarction is higher in chagasics with normal coronary arteries (with or without minimal atherosclerotic lesions), as compared with nonchagasics.

Adult↗
PubMed1994

Pathology of patients with Chagas' disease and acquired immunodeficiency syndrome.

The main pathologic findings in 23 patients with acquired immunodeficiency syndrome (AIDS) and Chagas' disease are reviewed; five are from our own experience and 18 from the literature. The presence of Trypanosoma cruzi parasites and/or T. cruzi antibodies in blood and cerebrospinal fluid was recorded and computerized tomograms of the brain were evaluated. Twenty (87%) of the 23 subjects developed severe, multifocal or diffuse meningoencephalitis with necrosis and hemorrhage associated with numerous tissue parasites. The second most severely affected site was the heart. Seven (30.4%) of the 23 cases had myocarditis on pathologic examination. It was acute in four patients, chronic in two, and simultaneously acute and chronic in one. Acute myocarditis and meningoencephalitis are interpreted as being caused by relapses of chronic T. cruzi infections. An AIDS permissive role is suggested for these conditions since immunologic defense against T. cruzi is mediated mainly by T lymphocytes, whose CD4 subpopulation is depleted in patients with this disease. Consequently, AIDS is a factor that may favor the reactivation of T. cruzi infections. The lesions reported in the association of Chagas' disease with AIDS were compared with those reported from patients without AIDS having fatal, acute, vector-transmitted infections, contaminated blood transfusions, or accidental exposures in the laboratory. For the latter three, meningoencephalitis is uncommon. Only immunosuppressed cases of Chagas' disease have been described as having a pseudotumoral presentation that shows expanding lesions with a mass effect in the cranial cavity that causes intracranial hypertension and simulates neoplasms (tumors such as gliomas, lymphomas, metastases, etc.).

Acquired Immunodeficiency Syndrome↗
PubMed1994

[The histopathology of the trabecular section of the right branch of the bundle of His in chronic chagasic patients with a right bundle-branch block].

PURPOSE: To evaluate possible morphological changes in chronic chagasic of the right bundle trabecular branch (RB) with right branch block (RBB) and to draw clinicopathological correlations. METHODS: Eight RBB chronic chagasic septo-marginal trabeculae (SMT) (group A), six left branch block (LBB) chagasic SMT (group B) and six SMT from non-chagasics with no heart disease (group C) were analyzed. Every SMT was completely embedded in paraffin, sub-serially sectioned to the end of the paraffin-block and the sections were processed for pathological study. RESULTS: Right bundle branch trabecular segment mononuclear infiltrate and/or fibrosis were found for 87.5 (7/8) of group A, 50% (3/6) of group B and 16.6% (1/6) of group C. Moderate mononuclear infiltrate and fibrosis were noted respectively for 3 and 1 cases, from group A. For the remaining group A cases and for all the group B and C cases the mononuclear infiltrate and fibrosis were slight. CONCLUSION: The frequency and degree of RB lesions might explain some of RBB. On the other hand, the absence of lesions in one case RBB and the slight degree of RB lesions in chagasics with LBB and in one non-chagasic case indicate that sometimes it is not possible to establish electrocardiographic-pathological correlations after TSM histological examination.

Adult↗
PubMed1993

Amplification of a Trypanosoma cruzi DNA sequence from inflammatory lesions in human chagasic cardiomyopathy.

The major cause of morbidity and mortality in Chagas' disease is a chronic inflammatory cardiomyopathy, which presents ten or more years following initial infection. Demonstration of Trypanosoma cruzi in cardiac tissue by routine microscopy or culture is difficult in these patients, which has suggested that persistent organisms are not required for chronic disease. Consequently, studies have focused on elucidating an autoimmune pathogenesis of chronic injury. To further assess the persistence of T. cruzi in host tissue, DNA extracted from formalin-fixed, paraffin-embedded autopsy specimens from seronegative or seropositive patients was amplified by the polymerase chain reaction using T. cruzi-specific primers. Trypanosoma cruzi DNA sequences were not consistently amplified from four seropositive patients who lacked evidence of fatal chronic chagasic cardiomyopathy (CCC) (0 positive of 12 heart samples, 0 positive of four gonadal samples, and 0 positive of four adrenal samples) or nine seronegative patients (0 positive of 27 heart samples, 0 positive of nine gonadal samples and 0 positive of nine adrenal samples). In seven seropositive patients with severe CCC, cardiac tissue adjacent to inflammatory infiltrates yielded amplified T. cruzi DNA sequences in 18 of 21 heart samples. Parallel testing of gonadal and adrenal tissues from these same patients produced detectable T. cruzi DNA in none of the gonadal tissue samples and one of the seven adrenals. Our studies demonstrate that T. cruzi, or a portion of its genome, is present in the inflammatory lesion of chronic cardiac Chagas' disease.

Adult↗
PubMed1993

Characterization of inflammatory infiltrates in chronic chagasic myocardial lesions: presence of tumor necrosis factor-alpha+ cells and dominance of granzyme A+, CD8+ lymphocytes.

The inflammatory infiltrates in the heart lesions of chronic chagasic cardiomyopathy are composed predominantly of small lymphocytes with admixed macrophages, plasma cells, and segmented leukocytes. The phenotypes of the lymphoid cells in these infiltrates of human Chagas' disease have not been previously detailed. We used a panel of monoclonal and polyclonal antibodies to immunohistochemically characterize the inflammatory cells in frozen and fixed cardiac tissues from autopsied patients with severe chronic chagasic cardiomyopathy. In all cases, the inflammatory lesions were dominated by CD8+ lymphocytes, many of which expressed granzyme A. A few macrophage-like cells that expressed tumor necrosis factor-alpha were observed in each case. Relatively few natural killer cells or B lymphocytes were found in the lesions. These findings in human chagasic lesions are compatible with concepts that involve cytolysis and fibrosis, and new experimental findings that emphasize potential roles for CD8+ T cells in Chagas' disease.

B-Lymphocytes↗
PubMed1993

Expression of major histocompatibility complex antigens and adhesion molecules in hearts of patients with chronic Chagas' disease.

We have previously reported that heart lesions in patients with chronic cardiac Chagas' disease are composed predominantly of granzyme A+, cytolytic CD8+ T lymphocytes. We now pursue this study in the immunopathology of chronic chagasic cardiomyopathy by investigation of the expression of HLA antigens, and adhesion molecules in the hearts of seven chagasic patients with cardiac disease, two asymptomatic chagasic patients, and seven normal controls. Comparative immunohistochemical analyses show that HLA-ABC antigen expression is enhanced on the myocardial cells of chagasic patients with chronic cardiomyopathy, suggesting a possible role for these cells as targets for the CD8+ cytolytic lymphocytes dominant in these lesions. The HLA-DR antigens are not observed on myocardial cells, but are consistently upregulated on the endothelial cells in the hearts of patients with chronic chagasic cardiomyopathy. Intercellular adhesion molecule is expressed by endothelial cells of both chagasic and nonchagasic individuals, but E-selectin was detected only on vessels of hearts from chagasic patients who had chronic cardiomyopathy. Most of the lymphocytes in these lesions express lymphocyte function antigen-1 (LFA-1), CD44, and very late antigen-4, and a few display weak expression of LFA-3. We propose that the expression of these adhesion molecules and major histocompatibility complex antigens by endothelial cells, myocardial cells, and lymphoid cells in these lesions contribute to the pathogenesis of chronic chagasic cardiomyopathy.

Adult↗
PubMed1993

[Daily and weekly circadian variations in sudden death in Chagas disease].

PURPOSE: To determinate the circadian daily and weekly variations in the incidence of sudden death due to Chagas' disease. METHODS: In 50 chronic chagasic individuals with sudden death due to Chagas' disease and in 473 individuals with natural, not sudden death, we analyzed both the day of the week and the time of the death. Statistical tests were applied to determine the significance of the difference between proportions and averages. RESULTS: For the chagasic group the values indicated a highly significant excess of lethality for the period between 12 and 6pm. The occurrence of the sudden death was the same in the different days of the week for both groups. CONCLUSION: The observed results suggest that the sudden death associated with Chagas' disease has a circadian pattern with a vespertine peak. Weekly variations in the sudden death of chronic chagasic individuals were not detected.

Adolescent↗
PubMed1992

A comparative study of four serological methods for diagnosis of acute and chronic Chagas' disease in Brazilian patients.

Complement fixation (CF), indirect immunofluorescence (IFAT), latex agglutination (LA) and the enzyme-linked immunosorbent assay (ELISA) were applied to assess the diagnostic value of antibody determination in Brazilian patients with acute or chronic Chagas' disease. Patients with various forms of leishmaniasis and healthy individuals from the endemic region were used as specificity controls. Whereas LA, IFAT and ELISA identified 81% of acutely ill patients, CF had no diagnostic potential in this phase of the disease. In later stages CF showed a sensitivity of 69% as compared to 100% for LA, IFAT and ELISA, irrespective whether patients presented clinically as chronic asymptomatic or chronic symptomatic cases. Cross-reactivity with anti-leishmania antibodies was observed in 23%, 38% and 77% of serum samples in LA, ELISA and IFAT, respectively, but not in CF.

Acute Disease↗