PubMed Health⌕ Search

Biomedical subjects

M L Higuchi

Publications and source records attributed to M L Higuchi.

14 recordsLinked to original sources
PubMed1992

CD8+ cells and natural cytotoxic activity among spleen, blood, and heart lymphocytes during the acute phase of Trypanosoma cruzi infection in rats.

The infection developed by Wistar Furth rats inoculated with the Y strain of Trypanosoma cruzi was the experimental model used in our study. The results showed that this infection altered considerably the CD4/CD8 lymphocyte subset ratio and the natural cytotoxic activity of mononuclear cells in the spleen, blood, and myocardial tissue. Concomitantly, an expansion of the number of cells expressing major histocompatibility complex (MHC) class II antigens was observed, as well as spontaneous development of high levels of blast cells, mainly in the spleen. The inflammatory infiltration of the myocardium, made up essentially of CD8+ cells (cytotoxic/suppressor T cells, natural killer cells), was initially found at 9 days postinfection, spread continuously, and was observed until the death of the animals at about 18 days postinfection. T. cruzi infection also enhanced the natural killer activity of mononuclear cells in the blood, spleen, and myocardium. Sorting these cells by affinity columns showed that the natural killer function was performed exclusively by the CD8+ population, which did not express MHC class II antigens. It was shown that the polyclonal T-lymphocyte activation induced by T. cruzi infection results in a wide distribution of CD8+ cells with enhanced natural cytotoxic activity in the spleen, blood, and cardiac tissue.

Acute Disease↗
PubMed1992

Fatal meningoencephalitis caused by reactivation of Trypanosoma cruzi infection in a patient with AIDS.

We report a case of fatal chagasic meningoencephalitis in an AIDS patient. Acute exacerbation of chronic Chagas' disease with involvement of the CNS is uncommon and occurs only in immunocompromised patients. This is the third such reported reactivation and it underscores the importance of considering Chagas' disease in HIV-positive patients from endemic regions.

Acquired Immunodeficiency Syndrome↗
PubMed1991

Decrease in sulphated glycosaminoglycans in aortic dissection--possible role in the pathogenesis.

STUDY OBJECTIVE: The aim was to investigate alterations in sulphated glycosaminoglycans in aortic dissection. DESIGN: Aortic fragments were taken from 10 patients within the first 3 d after onset of symptoms of aortic dissection and from nine age matched patients with no aortic disease. Sulphated glycosaminoglycans were analysed and quantified by agarose gel electrophoresis and densitometry after degradation with specific enzymes. MEASUREMENTS AND MAIN RESULTS: The amount of chondroitin sulphate was similar (7.14 v 7.60 mg.g-1 of dry tissue, n = 10, p greater than 0.5) in patients with dissection and in the control group. Total sulphated glycosaminoglycan content was decreased (11.51 v 14.26 mg.g-1 of dry tissue, n = 10, p less than 0.001). This difference was due to heparan sulphate (1.79 v 2.48 mg.g-1 of dry tissue, n = 10, p less than 0.05) and mainly to dermatan sulphate (2.58 v 4.18 mg.g-1 of dry tissue, n = 10, p less than 0.001). The ratio of 6-/4-sulphated disaccharides after chondroitinase ABC digestion was increased in the affected group. No correlation between these biochemical results and a histological evaluation of mucoid content was found. On the other hand, a significant increase in chondroitin sulphate could be observed related to aging. CONCLUSIONS: The diminution in sulphated glycosaminoglycans and its possible relationship with fat, collagen, and other extracellular matrix molecules could lead to a weakness in the aortic wall related to the dissection.

Adult↗
PubMed1990

Correlation between gallium-67 imaging and endomyocardial biopsy in children with severe dilated cardiomyopathy.

Fourty-four patients (aged 10 months to 15 years) were assessed in a double-blind study to observe the correlation between myocardial uptake of 67-gallium and endomyocardial biopsy in the detection of moderate to severe myocardial inflammation. The sensitivity and specificity of gallium-67 imaging were 87 and 81%, respectively. Based on these findings, immunosuppressive therapy can be assigned to children with dilated cardiomyopathy and positive myocardial uptake, since moderate and severe myocardial inflammation may be detected by this non-invasive method.

Adolescent↗
PubMed1990

[Immunosuppressive drugs for the treatment of active myocarditis in children. Hemodynamic evaluation].

PURPOSE: To analyse hemodynamic parameters (left ventricles ejection fraction, cardiac index, mean pulmonary wedge pressure and left ventricle diastolic diameter, in a group of children with active myocarditis (diagnosed by endomyocardial biopsy) pre and post treatment with conventional therapy and immunosuppressive drugs (isolated prednisone or prednisone associated with azathioprine or cyclosporine). PATIENTS AND METHODS: Forty-four pediatric patients with active myocarditis were studied. Twenty males and 24 females from 10 months to 15 years old (median = 1.3 years). All patients were submitted to hemodynamic study and endomyocardial biopsy. The hemodynamic parameters mentioned above were analysed before and after the proposed therapy. The patients were distributed in group according to the admission in the protocol, group I (9 pts)--conventional therapy (CT); group II (12 pts)--CT plus prednisone; group III (16 pts)--CT plus prednisone plus azathioprine; group IV (13 pts)--CT plus prednisone plus cyclosporine. RESULTS: Forty-four patients were submitted to four different groups of therapeutic protocol. The hemodynamic parameters were analysed in each of them. Left ventricle ejection fraction were no significantly different in the pre and post therapeutic scheme in group I and II, they were significantly higher (p less than 0.05) in group III and IV. The same happened with cardiac index. The mean pulmonary wedge pressure no presented statistical differences in group I and II before and after treatment but significantly lower lends were observed in group III and IV. The same behavior were noted in the left ventricle end diastolic diameter. CONCLUSION: The association of azathioprine or cyclosporine to prednisone presented better results in the left ventricle function, when compared with conventional drugs or isolated use of prednisone, based in the analysis of same hemodynamic parameters.

Adolescent↗
PubMed1990

[Lymphocytic myocarditis. Response to treatment with immunosuppressive drugs].

PURPOSE: To evaluate immunosuppressive drugs on the treatment of myocarditis. PATIENTS AND METHODS: Right ventricular endomyocardial biopsy was performed in 102 patients with dilated cardiomyopathy. According to histopathologic aspect the patients were divided into two groups: I--with active lymphocytic myocarditis (ALM); II--without ALM: 51 patients. Ten patients from group I (Ib), with moderate or intense myocarditis were treated with prednisone and azathioprine during six months. RESULTS: After six months of observation, in group Ia (41 patients): 41 improved, 22% worsened and 12% died; in group Ib (10 patients): 60% improved, 10% worsened and 30% died; 51 patients in group II: 59% improved, 17% worsened and 10% died. Control biopsy on group Ib showed decrease of myocarditis in 62%. CONCLUSION: Immunosuppressive drugs do not always improve quality of life, or increase the survival, although in more than 50% of the cases it was possible to control inflammatory process.

Adolescent↗
PubMed1990

Bizarre nuclei of myocardial fibers in an infant with dilated cardiomyopathy. Light, electron-microscopic, and immunoperoxidase studies of a necropsy case.

The authors present the case of a 9-month-old child with clinical dilated cardiomyopathy that at necropsy showed myocardial cells with volumous, bizarre, and pleomorphic nuclei. These nuclear alterations were also found in other tissues. The myocardial ultrastructural studies revealed degenerative cytoplasmatic changes, nuclear membrane invaginations forming tubules, vesicles, and cytoplasmatic pseudoinclusions, and intranuclear vermicelar bodies, which all suggest virus-induced lesions. Although the ultrastructural studies and immunoperoxidase tests for virus identification were negative, the authors believe that a virus is most probably the agent of these alterations. This case seems to be the first reported on dilated cardiomyopathy with bizarre nuclear alterations in the myocardial fibers having strong evidence pointing to viral etiology.

Cardiomyopathy, Hypertrophic↗
PubMed1989

Chagas' heart disease and myocardial infarct. Incidence and report of four necropsy cases.

The authors describe the clinical-pathologic findings in four patients with myocardial infarct (MI) associated with Chagas' disease, found among 181 autopsies of chronic congestive cardiac chagasic patients. Organized thrombo-embolus was found in the epicardial portion of a coronary artery in one instance and thrombosis in the apex of the left ventricle as well as systemic infarcts were found in all cases. These data suggest thrombo-embolism, probably from the apex of the left ventricle, as a possible cause for the regional (large; transmural) MI in chronic Chagas' heart disease. The mechanism usually operative in MI, i.e. complicated atherosclerosis, was not present in the patients of this series. Moreover, our data do not support either small artery disease or heart denervation as etiologic factors for regional MI.

Adult↗
PubMed1989

[Comparison of histologic changes in Chagas' cardiomyopathy and dilated cardiomyopathy].

In this study the histopathologic features of Chagas' disease and idiopathic dilated cardiomyopathy were compared in 38 patients with congestive heart failure, classes II or III. Biopsy specimens were obtained with the Stanford model needle for right ventricle. Twenty-two patients presented non-chagasic dilated cardiomyopathy, and 16 were carriers of Chagas' disease. Twenty-three were male and 15 were female; their ages varied 18 and 49 years (mean 35.5). Fibrosis was slightly more frequently and intense in Chagas' disease than in dilated cardiomyopathy. Myocarditis aspect also was more frequent in Chagas' disease than in dilated cardiomyopathy (62.4% vs. 50%), with all cases showing a chronic form; acute myocarditis was observed only in dilated myocardiopathy. These differences, however, did not reach statistical significance. In conclusion, the presence of fibrosis, hypertrophy and moderate to severe degrees of chronic inflammatory infiltrate are suggestive of but not pathognomonic of Chagas' disease. On the other hand, dilated myocardiopathies are more frequently associated with less fibrosis or hypertrophy and the presence of mild degree of inflammatory infiltrate. The arrangement of this inflammatory infiltrate tends to be diffuse in dilated cardiomyopathy and in chagasic myocarditis it is multifocal, very similar to the histopathological aspect found in myocardial rejections episodes of transplanted hearts.

Adolescent↗
PubMed1989

Thin-section and freeze-fracture study of post-mortem changes in dog myocardium.

1. Fragments of dog hearts submitted to 1, 6, 10, 24 and 48 h of autolysis at 20 degrees C were studied with freeze-fracture and thin-section techniques under the transmission electron microscope. 2. The freeze-fracture replicas revealed maximal reduction in the mean number and clustering of intramembrane particles at 6 h post mortem, indicating irreversible cellular damage. However, signs of lethal damage (intramitochondrial amorphous dense bodies) were not observed in thin sections of the same material. 3. The present study indicates that signs of irreversible damage similar to that occurring in in vivo ischemic alterations can be detected earlier by the freeze-fracture technique than by the thin-section technique.

Animals↗
PubMed1989

[Histopathologic aspects of hyperacute graft rejection in human cardiac transplantation. A case report].

The first case of a hyperacute rejection of a human cardiac allograft in Brazil is reported. The histopathological aspects of hyperacute cardiac rejection in its earlier moments are described when degenerative and necrotic features of the cardiac fibers are not totally developed. The authors believe that neutrophilic exudation and lesion of the vessel wall are good signs for a correct diagnosis of hyperacute rejection. Furthermore, they observed that the process is diffuse enough to justify the indication of endomyocardial biopsy when there are reasons to suspect this diagnosis. Presence of IgM and complement (C3) are also useful.

Adult↗
PubMedDate not supplied

Acute myocardial infarction with diffuse endarteritis, contraction bands, and distal thrombosis of the coronary arteries in a heart transplant patient.

The case history of a heart transplant patient who died of an acute myocardial infarction 6 months after the procedure is described. The finding of contraction bands and thrombosis associated with endarteritis suggests that coronary vasospasm may have contributed to the acute myocardial infarction during an episode of vascular rejection.

Adult↗
PubMedDate not supplied

Usefulness of T-cell phenotype characterization in endomyocardial biopsy fragments from human cardiac allografts.

The mean numbers of cytotoxic/suppressor (CD8+) and helper/inducer (CD4+) T cells were determined in 111 successive endomyocardial biopsy fragments from eight cardiac allograft patients in an attempt to define their significance in the rejection process. Endomyocardial fragments from autopsy or donor hearts without myocarditis were evaluated as controls. The mean numbers of CD8+ and CD4+ T cells in the control group were 0.8 and 0.5 cells/field at x400 magnification, respectively. The mean numbers of CD8+ T cells per field in the cardiac allograft biopsies were 2.4, no rejection group; 5.4 mild rejection group; 11.1, moderate rejection group; and 4.9, resolving rejection group. The mean numbers of CD4+ T cells per field for the same groups were slightly lower than those of the CD8+ T cells. The number of CD8+ T cells per field reliably indicated the severity of rejection. Patients with normal numbers of CD8+ T cells and no evidence of rejection had better long-term outcomes (two or fewer moderate rejection episodes) than those with higher numbers. Analysis of the data suggests that the presence of two or fewer CD8+ T cells/field may be considered normal in the myocardial interstitium. The diagnosis of no evidence of rejection should be coupled to the presence of a normal number of CD8+ T cells. High numbers (greater than 10) of CD8+ T cells, even in absence of myocytolysis, should be treated more assertively, including the use of high doses of prednisone, because all our cases with high numbers showed a worse histologic picture at the subsequent biopsy.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗