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Biomedical subjects

M L Higuchi

Publications and source records attributed to M L Higuchi.

At least 19 recordsLinked to original sources
PubMed2002

Relevance of apoptosis and cell proliferation for survival of patients with dilated cardiomyopathy undergoing partial left ventriculectomy.

BACKGROUND: Cardiomyocyte apoptosis as well as proliferation have been described in congestive heart failure, but their clinical relevance remains unclear. In order to clarify whether apoptosis and cell proliferation occur in patients with idiopathic dilated cardiomyopathy and whether their degree in left ventricle fragments resected during partial left ventriculectomy has any influence on the outcome after this surgery, we compared their occurrence in four groups of patients: group A, short-term survivors (n = 18); group B, deaths within 6 months of the surgery (n = 13); group C, long-term survivors (n = 12); and Group D, deaths within 60 months (n = 19). DESIGN: Apoptotic cardiomyocytes and interstitial cells were quantified in left ventricle fragments from 31 patients with idiopathic-dilated cardiomyopathy using the TUNEL assay. Cell proliferation was quantified in parallel sections by KI-67 immunohistochemistry. RESULTS: Apoptotic cells were present in the majority of cases (n = 24) and proliferative cells in all cases. Whereas there was no significant difference regarding all parameters examined between Groups A and B, there was a highly significant difference between Groups C and D in the number of apoptotic cardiomyocytes (P = 0.012) and apoptotic interstitial cells (P = 0.006). There was no significant relationship between apoptotic cardiomyocytes and KI-67-positive cardiomyocytes, but a negative correlation between apoptotic interstitial cells and KI-67-positive interstitial cells (r = -0.383; P = 0.028). CONCLUSION: Cardiomyocyte apoptosis and proliferation occur in the majority of patients with idiopathic-dilated cardiomyopathy. High numbers of apoptotic cardiomyocytes and apoptotic interstitial cells are significantly related to a bad late outcome after partial left ventriculectomy.

Adult↗
PubMed2001

Histopathological findings in skeletal muscle used in human dynamic cardiomyoplasty.

Patients submitted to dynamic cardiomyoplasty had an initial clinical improvement followed by a decrease in cardiac failure indices. A histopathological study of the skeletal muscle was undertaken to explain this. Latissimus dorsi fragments from 15 patients submitted to dynamic cardiomyoplasty in a 1:1 (heart beat:muscle stimulation) conditioning were analysed by light microscopy. The interval between surgery and obtaining the specimens (13 from necropsies, two from heart transplants) ranged from 37 days to 6 years. Nuclear clumps and internalization, the presence of round fibres, inflammation, and fibrosis were analysed semi-quantitatively; the thickness of muscle fibres and the percentage of tissue fat were measured by image analysis. The quantitative data were also compared, in 12 cases, with gender- and age-matched necropsy controls. The mean thickness of muscle fibres in cases and controls was 27.21+/-5.33 and 40.84+/-9.42 microm, respectively (p=0.001). The percentage of tissue fat in cases and controls was 12.04+/-12.66% and 0.93+/-0.91%, respectively (p=0.008). The duration of grafts correlated positively with the quantity of nuclear clumps (R=0.80, p<0.001) and round fibres (R=0.53, p=0.04), as well as with the percentage of tissue fat (R=0.68, p=0.005). Accordingly, a negative correlation was found between the duration of grafts and the mean diameter of fibres, characterizing muscle atrophy (R=-0.66, p=0.01). The longer the post-surgical period, the more intense the degenerative lesions. This study shows that skeletal muscle used in human dynamic cardiomyoplasty may atrophy and be replaced by fat when stimulation is synchronized to every cardiac beat. These findings could play a role in explaining the long-term results of this surgical procedure.

Adipose Tissue↗
PubMed2001

Cardiac rhabdomyomas exhibit a fetal pattern of atrial natriuretic peptide immunoreactivity.

Rhabdomyomas are the most common heart tumors seen in infancy. However, whether they represent hamartomas or true neoplasms derived from cardiomyocytes is still controversial. The fetal pattern of atrial natriuretic peptide (ANP) expression (predominant in the atrial and ventricular subendocardium) becomes altered during the early postnatal period to that typical of the adult (all atrial cardiomyocytes and some cells in the ventricular impulse-conducting system). To better comprehend the nature and origin of cardiac rhabdomyomas, we investigated the immunohistochemical expression of ANP in seven surgically excised ventricular specimens and two necropsy cases of multiple, atrial, and ventricular rhabdomyomas in children aged 1 to 34 days. Immunogold labeling for ANP at the ultrastructural level was also performed on three ventricular tumors. Although all atrial tumors were immunoreactive for ANP, these usually showed a variable number of faintly positive cardiomyocytes, contrasting with the diffuse and intense immunoreactivity of the surrounding atrial myocardium. ANP was detected in the ventricular tumors of five (56%) of the nine cases. The positive ventricular tumor cells predominated in the subendocardium and areas with prominent fibrous tissue, usually around blood vessels. Immunoelectron microscopy of the ventricular tumors demonstrated rare, positive cytoplasmic granules surrounded by membranes, usually located near the nuclei. We conclude that cardiac rhabdomyomas exhibit a fetal pattern of ANP immunoreactivity, which suggests delayed maturation of the tumoral cardiomyocytes, reinforcing the notion that cardiac rhabdomyomas are fetal hamartomas.

Atrial Natriuretic Factor↗
PubMed2001

Coenzyme Q10 exogenous administration attenuates cold stress cardiac injury.

The influence of coenzyme Q10 (CoQ10) in cold stress test (-15 degrees C for 4 hours) cardiac functional impairment was studied in isolated isovolumic heart of control rats (C; n=12) and of placebo (P; n=11) and treated rats (CoQ10; n=10). In addition, electron microscopic evaluation of left ventricular (LV) slices (n=3 in each group) allowed us to analyze the myocardial ultrastructure. Maximal values of developed pressure (DPmax) were similarly decreased in cold stressed animals (C=129+/-3.9 mmHg; P=106+/-6.7 mmHg; CoQ10=91+/-3.9 mmHg); however, volume-induced enhancement of pressure generation (slope of DP volume relations: C=0.248+/-0.0203 mmHg / microl; P=0.2831+/-0.0187 mmHg / microl; CoQ10=0.2387 ( 0.0225 mmHg / microl; p > 0.05), and the duration of systole (C=80+/-1.6 ms; P=78+/-1.3 ms; CoQ10=80+/-2.7 ms) were not altered. Myocardial relaxation, evaluated by the relaxation constant (C=39+/-1.9 ms; P=42+/-3.4 ms; CoQ10=51+/-6.0 ms), as well as resting stress / strain relations were unaffected by cold stress. Myocardial samples showed that pretreatment with CoQ10 attenuates myofibrillar and mitochondrial lesions, and prevents mitochondrial fractional area increase (P: 53.11%>CoQ10: 38.78%=C: 33.87%; p< 0.005) indicating that the exogenous administration of CoQ10 can reduce cold stress myocardial injury.

Animals↗
PubMed2000

Autopsy findings in early and late postoperative death after partial left ventriculectomy.

BACKGROUND: Partial left ventriculectomy (PLV) is an alternative to heart transplantation for patients with severe heart failure. However, this procedure is accompanied by high morbidity and mortality. Therefore, we studied the hearts of 12 patients who underwent this procedure to increase our understanding of the causes of bad outcome. METHODS: We analyzed the autopsy hearts of 11 of 16 patients who died after PLV, and one heart from a patient who underwent heart transplantation. RESULTS: Six patients died less than 30 days postoperatively, 4 of cardiogenic shock, 1 of arrhythmia, and 1 of coagulopathy. Five patients died from 36 to 120 days after the procedure, 4 of cardiogenic shock and 1 of arrhythmia. The patient who underwent heart transplantation had a cardiogenic shock 230 days after PLV. Ten hearts weighed more than 500 g and nine had myocardial infarction that extended to the papillary muscles. Four patients had infarction of both papillary muscles and 3 of them had episodes of arrhythmia, suggesting some relation between these events. CONCLUSIONS: We found several important morphologic clues for bad outcome: infarction of both papillary muscles, which may be associated with the development of arrhythmia, and myocardial infarction and pericardial hemorrhage, which may contribute to the outcome of heart failure.

Adult↗
PubMed2000

CMV and transplant-related coronary atherosclerosis: an immunohistochemical, in situ hybridization, and polymerase chain reaction in situ study.

Accelerated graft coronary atherosclerosis is the main obstacle to long-term survival in patients who have had a heart transplant. A possible involvement of the human cytomegalovirus (HCMV) in this type of coronary atherosclerosis has been postulated by many authors but has not been definitively demonstrated. In an attempt to clarify the role of HCMV infection in the pathogenesis of this complication, we looked for in situ antigens or DNA of HCMV in 30 coronary artery segments obtained at necropsy from patients who had undergone orthotopic cardiac transplantation at the São Paulo Heart Institute. We tried to correlate these HCMV markers with the presence of inflammation and/or atherosclerosis in histologic sections. The patients were grouped as follows: GI, less than 170 days of graft survival and absent/mild atherosclerosis; GII, more than 170 days of graft survival and absent/mild atherosclerosis; GIII, more than 170 days of graft survival and severe/moderate atherosclerosis (170 days was the shortest graft survival time associated with atherosclerosis). The search for HCMV genome and antigens in the coronary artery sections was performed using immunohistochemistry, in situ hybridization, and polymerase chain reaction in situ techniques. Immunohistochemistry and in situ hybridization revealed no evidence of HCMV in all 30 cases. Polymerase chain reaction in situ revealed scarce HCMV-positive lymphocytes in two cases (one each from GI and GIII) located in the adventitial layer. These findings preclude a direct role for the HCMV in the pathogenesis of accelerated graft coronary atherosclerosis. However, the possibility of an indirect effect of the virus, such as an immune-mediated inflammatory response by the host that increases the expression of histocompatibility antigens, leading to tissue injury, cannot be excluded.

Adolescent↗
PubMed2000

Systematic mapping of hearts from chronic chagasic patients: the association between the occurrence of histopathological lesions and Trypanosoma cruzi antigens.

To investigate the role played by Trypanosoma cruzi in the pathogenesis of chronic chagasic cardiopathy, the myocardiums of 12 hearts from individuals who had this condition were mapped in detail. Attempts were made to associate the histopathological lesions observed with the presence of parasitic antigens in the affected tissue. Samples from 26 regions of each heart were submitted to histological analysis and immunostained for the presence of T. cruzi. All cases showed at least one positive region for antigens, but the quantity of antigen detected varied greatly. The regions showing the greatest pathological changes were the inferior atrial septum, the basal and apical portions of the ventricular septum, and the posterior basal and lateral pre-apical regions of the left ventricle. The posterior wall of the right atrium and the posterior basal wall of the left ventricle presented the greatest intensities of inflammation. Fibrosis was intense in the right atrium, the posterior basal and pre-apical left ventricular free walls and the apex. The regions in which T. cruzi antigens were detected showed the most intense inflammation. However, as there was no significant correlation between the intensity of the lesions and the quantity of parasitic antigen, other mechanisms, such as auto-immunity or hypersensitivity, may stimulate the inflammation.

Adolescent↗
PubMed2000

Detection of Mycoplasma pneumoniae and Chlamydia pneumoniae in ruptured atherosclerotic plaques.

This paper reports what is apparently the first observation of Mycoplasma pneumoniae in association with Chlamydia pneumoniae in thrombosed ruptured atheromas. We performed electron microscopy and in situ hybridization in specimens from three patients who died of acute myocardial infarction. These patients had typical symptoms of acute ischemic syndrome. Mycoplasmas were present mainly in the lipid core of the ruptured thrombosed plaque. Vulnerable atheromas are rich in cholesterol and may favor the growth of mycoplasmas, the only microorganisms that require cholesterol for survival. We suggest that the association of Mycoplasma pneumoniae and Chlamydia pneumoniae may increase the virulence of these microorganisms, favoring proliferation, plaque inflammation and possibly plaque rupture.

Chlamydia Infections↗
PubMed1999

Histological evidence of concomitant intramyocardial and epicardial vasculitis in necropsied heart allografts: a possible relationship with graft coronary arteriosclerosis.

BACKGROUND: The significance of medial lymphocytic vasculitis in intramural coronary vessels in heart transplantation is very poorly understood. This study was designed to identify histological evidence of an association between the presence of epicardial coronary lesions and the occurrence of intramyocardial vasculitis and/or myocardial ischemia. METHODS: We analyzed the frequency of medial vasculitis and other myocardial histological alterations in a retrospective study of 24 human cardiac allografts from patients who died of ischemic heart disease and/or myocardial rejection. RESULTS: Medial lymphocytic vasculitis in the myocardium was associated with vasculitis in the vasa vasorum of the epicardial coronary arteries and the presence of microfoci of acute myocardial infarction but was independent of the occurrence of myocardial fiber rejection. Chronic graft epicardial arteriopathy revealed two patterns of lesions. One pattern was similar to that of usual atherosclerosis, compromising mainly the proximal segments of the coronary artery, and was not associated with intramural vasculitis. The other pattern demonstrated diffuse involvement of the epicardial artery associated with vasculitis of its vasa vasorum and lymphocytic vasculitis of the intramural vessels. This second type of epicardial coronary lesion seemed to evolve to fibrotic arteries with thinned walls, frequently demonstrating aneurysmal dilatation with severe fibrosis of the adventitia and poor vasa vasorum. CONCLUSION: Medial vasculitis affecting intramyocardial vessels is associated with adventitial epicardial coronary vasculitis in the transplanted heart. The process of vasculitis may be involved in the development of chronic graft arteriosclerosis and is associated with ischemic myocardial lesions, but seems independent of myocardial fiber rejection.

Acute Disease↗
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↗
PubMed1999

Different microcirculatory and interstitial matrix patterns in idiopathic dilated cardiomyopathy and Chagas' disease: a three dimensional confocal microscopy study.

OBJECTIVE: To analyse the morphological aspects of the extracellular matrix and microcirculation to clarify whether chronic Chagas' cardiopathy (CCC) is an accurate model to study the pathogenesis of idiopathic dilated cardiomyopathy (IDCM). DESIGN: Thick histological myocardial sections were prepared to analyse collagen, and microcirculation was examined during confocal laser and light microscopy. SETTING: The specimens were prepared at the pathology service of the Heart Institute of São Paulo, Brazil. PATIENTS: Nine control hearts, eight IDCM hearts, and 10 CCC hearts were studied after necropsy. MAIN OUTCOME MEASURES: The number of collagen struts per 100x field, the area of fibrosis (%), and the diameters of arterioles and capillaries were measured in each heart to establish outcome. RESULTS: A smaller number (mean (SD)) of collagen struts was seen in the hearts in the IDCM group (9.1 (4.1)) than in the control (22.4 (3.2)) (p < 0.05) or CCC (15.7 (7.4)) (p > 0.05) groups. Fibrosis was greater in the CCC hearts (13.8 (10.5)%) than in the IDCM hearts (5.9 (6.6)%) (p > 0.05). Major increases in arteriole (65.4 (9.9) microm) and capillary (9.9 (1.7) microm) diameters were seen in the CCC hearts but not in the IDCM hearts (arteriole diameter 40.3 (7.9) microm; capillary diameter 7.9 (1.3) microm). CONCLUSIONS: Hearts demonstrating CCC and IDCM present different extracellular and microvessel alterations. This suggests that distinct pathogenic mechanisms are responsible for each condition and that CCC is not an effective model to study IDCM.

Adolescent↗
PubMed1998

Determinants of midterm outcome of partial left ventriculectomy in dilated cardiomyopathy.

BACKGROUND: Partial left ventriculectomy has been proposed for treatment of severe cardiomyopathies. This study reports midterm results of this procedure in 37 patients with dilated cardiomyopathy. METHODS: All patients were in New York Heart Association class III (16) or IV (21). Partial ventriculectomy was associated with mitral annuloplasty in 27 patients and with mitral replacement in 2. RESULTS: There were seven operative deaths (18.9%). During a mean follow-up of 18.2+/-9.3 months, 9 more patients died. Actuarial survival was 56.7%+/-8.1% at 6 and 24 months. Analysis of factors influencing outcome showed that midterm survival was significantly affected only by myocardial cell diameter. Otherwise, functional class improved from 3.5+/-0.5 to 1.8+/-0.9 in the survivors (p < 0.001). Furthermore, left ventricular diastolic volume decreased from 523+/-207 to 380+/-148 mL (p < 0.001), and left ventricular ejection fraction increased from 17.1%+/-4.6% to 23%+/-8% (p < 0.001), whereas significant changes in cardiac index, stroke index, and pulmonary pressures were found at 1 month of follow-up. Although left ventricular diastolic volume tended to increase in the late postoperative period, left ventricular ejection fraction and hemodynamic variables did not change significantly. CONCLUSIONS: Partial ventriculectomy improves left ventricular function and congestive heart failure in patients with dilated cardiomyopathy for up to 24 months of follow-up. Nevertheless, this procedure's clinical application is limited by the high mortality observed in the first postoperative months. Otherwise, new perspectives may be advised by the identification that partial ventriculectomy results seem to be influenced by compromised myocardial cells.

Adult↗
PubMed1998

Distribution of hyaluronan and dermatan/chondroitin sulfate proteoglycans in human aortic dissection.

Aortic dissections (AD) are characterized by the separation of the artery into two sheets, possibly due to fragility of the vessel wall. A mucoid histological pattern, imparted to the tissues mainly by hyaluronan and proteoglycans, can be seen in "cysts" and, in chronic cases, in a band of repair tissue. We studied the localization of hyaluronan, versican, decorin and biglycan in situ in aortas of 21 patients with recent AD, 8 with chronic AD and in 15 control cases. None of these substances was increased in the areas of mucoid "cysts" that possibly contain anomalous material. Similar distributions were seen in normal and dissected aortas: versican and hyaluronan were more prominent in the external half of the medial layer where the dissection usually occurs. Since these molecules play a role in resistance to compression, disorders not detected by our method may be involved in aortic dissection. Hyaluronan was seen adjacent to fibrin at the dissection tear, probably as an early wound repair phenomenon. Biglycan, hyaluronan and mostly versican are seen during advanced repairing. The mucoid deposits may represent various compounds which reflect different disorders in vascular biology.

Acute Disease↗
PubMed1998

Higher incidence of malignant neoplasms after heart transplantation for treatment of chronic Chagas' heart disease.

BACKGROUND: Heart transplantation is a new therapeutic procedure to treat heart failure resulting from Chagas' disease. Experimental studies have demonstrated neoplastic effects of benznidazole, which is used for treatment of Trypanosoma cruzi infection. We compared the incidence and characteristics of neoplasia after heart transplantation for treatment of chronic Chagas' disease with those of other diseases. METHODS: Sixteen patients with Chagas' disease and 75 patients with other diseases underwent heart transplantation. Benznidazole was administered to 14 patients with Chagas's disease either for prophylaxis (4 patients) or for treatment of Chagas' disease reactivation (10 patients). RESULTS: The survival rate of patients in the nonchagasic group was 90% at 1 year and 82.4% at 2 years, and the survival rate in the chagasic group was 63% at 1 year and 57% at 2 years. Six of 16 patients (37.5%) with Chagas' disease had malignant tumors after a mean follow-up time of 25.3+/-2.1 months in contrast to 2 of 75 patients (2.7%) in the nonchagasic group after 34.6+/-3.6 months of follow-up. In the chagasic group, lymphoproliferative disorder was diagnosed in three patients, Kaposi's sarcoma in two, and squamous cell carcinoma in one patient. Reactivation of T. cruzi infection was diagnosed in all patients who had lymphoproliferative disorder. One patient without Chagas' disease had lymphoproliferative disorder in the lung, and another had malignant schwannoma affecting the skin. CONCLUSIONS: We found a higher incidence of malignant neoplasia after heart transplantation for treatment of chronic Chagas' disease. It is likely that the neoplasia is the result of chronic infection with an immunomodulator protozoan, immunosuppression, reactivation of the T. cruzi infection, or the toxicity of therapeutic intervention with benznidazole.

Adult↗
PubMed1997

[Systematic quantification of the arteries in lung biopsies of patients with congenital heart defects and its contribution to the therapeutic management].

PURPOSE: To determine the value of the quantitative analysis of lung biopsies from patients with congenital cardiac defects. METHODS: Fourty nine biopsies were examined, from patients: 43 patients increased pulmonary blood flow, 3 with pulmonary atresia and large systemic-to-pulmonary collateral vessels, and 3 with decreased pulmonary flow. The degree of lesion was determined as in Heath-Edwards and of Rabinovitch and col. RESULTS: The Heath and Edwards grade was determined in 41 cases; I in nine; II in 23; III in eight; IV in one; 3 biopsies showed evidence of reduced pulmonary flow and 5 had no signs of vascular disease. The Down patients (7) presented a greater proportion of severe lesions. Quantitative evaluation was obtained in 35 biopsies: 11 had grade B and 24 had grade C. Wall atrophy and dilatation of intraacinar arteries were detected in 7 cases, what suggested the existence of obstructive lesions in proximal vessels, even if not sampled. Medical thickness greater than 2 times the normal were observed in pre-acinar arteries from 14 biopsies. CONCLUSION: The morphometric approach allowed us to detect severe lesions which the qualitative analysis alone would not indicate adequately. In the patients presenting decreased pulmonary flow, morphometry made possible to assess if the degree of arterial wall hypertrophy was compatible with a surgery of atrio-pulmonary anastomosis.

Adolescent↗
PubMed1996

Heart transplantation for chronic Chagas' heart disease.

BACKGROUND: Chagas' disease has been considered a contraindication to heart transplantation as Trypanosoma cruzi infection could recur after immunosuppression. METHODS: We report the follow-up of 22 patients who underwent orthotopic heart transplantation for treatment of end-stage chronic Chagas' heart disease, divided in two groups. Group 1 consisted of 9 patients operated on from September 1985 to June 1991, and group 2 patients underwent transplantation from July 1991 to June 1995. After our early experience with group 1, we attempted to use a lower cyclosporine dosage in group 2. RESULTS: Total actuarial survival at 24 months was 60%, and it was better for group 2 (33% for group 1, 80% for group 2, p = 0.008). Parasitemia occurred similarly in both groups, but Chagas' disease reactivation was seen in 5 group 1 patients and in 1 group 2 member (p < 0.002). Neoplasia developed in 5 group 1 patients and 1 group 2 patient, and contributed to death in 3 of them. CONCLUSIONS: These data demonstrate satisfactory outcome of cardiac transplantation in patients with end-stage Chagas' heart disease in the second phase of our experience. Further progress is necessary to improve the results and evaluate its proper role in the management of this disease.

Actuarial Analysis↗
PubMed1995

Gamma delta T cells play no major role in human heart allograft rejection.

To investigate the role of gamma delta T cells in human heart transplantation, we searched for this T cell population in endomyocardial biopsies as well as in T cell lines and clones derived from graft-infiltrating lymphocytes. The number of gamma delta T cells in endomyocardial biopsies from transplanted patients (n = 55) was mostly low and did not differ significantly from nontransplanted patients (n = 21). Moreover, there was no association of gamma delta T cell distribution with rejection status or with time posttransplantation. Graft-derived T cell lines were established in the presence of autologous feeder cells and recombinant interleukin-2 to favor the growth of in vivo-activated T cells. Twenty T cell lines analyzed by flow cytometry showed low percentages of gamma delta T cells, and we were unable to obtain gamma delta T cell clones for functional studies. These results show that gamma delta T cells are poorly expressed on human heart allograft infiltrates and indicate that, when present, they are not activated in the graft. Our data suggest that gamma delta T cells do not have a major role in human heart rejection.

Antigens, CD↗