Zu-Xi Yu

Histopathologic and ultrastructural observations of acute and convalescent myocarditis: A serial endomyocardial biopsy study

SummarySerial endomyocardial biopsy findings were analyzed in ten cases with acute myocarditis of possible viral origin. The histopathologic findings were analyzed at the acute (0–10 days after the onset), subacute (11–21 days), and convalescent stages (22–167 days). The incidence and severity of various cardiac myocyte and interstitial changes were compared at each stage of the disease.The time-course changes of the histopathologic findings in acute myocarditis were as follows. At the acute stage, we observed: (1) interstitial cell infiltration composed of fibroblasts, macrophages, and lymphocytes, (2) fragmentation of the muscle bundles, (3) myocytolytic changes, (4) swelling and scarcity of the cytoplasm and swelling of nuclei, (5) variation in size of the myocytes, (6) disarrangement of the muscle bundles, (7) interstitial edema, (8) increased glycogen deposition in the myocytes, (9) abnormal branching of the myocytes, and (10) interstitial fibrosis. At the convalescent stage, most of the above findings could still be seen except for myocytolytic changes, swelling of myocytes, and interstitial edema. At the subacute and convalescent stages, an increase in abnormal branching and in double nuclei in the myocytes and nuclear degeneration became observable. A further control study comparing the changes at the convalescent stage of myocarditis and the myocardial changes in cases with chronic right ventricular overload in 58 cases revealed that in the former fragmentation of the muscle bundles, abnormal branching, size variation, glycogen deposition, and large mononuclear cell infiltrations were significantly more frequent.Ultrastructural observation of the myocytes revealed that they have a great potentiality for regeneration; myocytes showing severe myocytolytic changes may recover to regain an architecture of almost normal appearance.

A comparative ultrastructural study on the nature of interstitial cell constituents in idiopathic myocarditis and myocardial infarction

SummaryIn order to observe the characteristics of interstitial cellular proliferation in cases with myocarditis of possible viral origin, a systematic ultrastructural analysis of the cell components in the interstitium was made employing endomyocardial biopsy at the acute (0–10 days after onset), subacute (11–25 days), and convalescent stages (26–167 days) of the disease in ten cases. For comparison, myocardial specimens from cases with myocardial infarction were taken from early autopsy cases or from tissue obtained during surgery. The dominant interstitial cells observed in the acute stage of myocarditis were fibroblasts (38.3%±17.5%, mean ±SD), macrophages (23.3%±12.1%), and lymphocytes (18.0%±18.1%); at the convalescent stage, fibrocytes (44.6%±20.2%) and fibroblasts (22.5%±8.0%) were commonly seen. In myocardial infarction, the dominant cells were macrophages (35.0%±16.0%) and neutrophils (26.0%±13.9%) at the acute stage, and lymphocytes (30.0%±17.8%), plasma cells (27.1%±20.0%), and macrophages (26.4%±11.4%) at the late stage. Thus, some differences between the two diseases could be recognized.

Immunohistocytochemical localization of alpha human atrial natriuretic peptide in human atrium obtained from endomyocardial biopsy and cardiac surgery

SummaryTo demonstrate the localization of atrial natriuretic peptide (ANP), we were able to apply the indirect and avidin-biotin peroxidase complex (ABC) methods for immunohistocytochemical analysis on sections with routine fixation and embedding for conventional histopathological and ultrastructural examinations. Human right and/or left atrial myocardial specimens were obtained at cardiac surgery (n=12) or by right atrial endomyocardial biopsy, employing Konnos catheter bioptome (n=30). In both specimens, ANP-like immunoreactivity was observed mainly around the nuclei and in specific granules in atrial myocytes. These new techniques are, therefore, considered to be useful for clinical analysis employing minute human atrial specimens in various heart diseases.

Double nuclei in endomyocardial biopsy: A comparative study of the incidence in myocarditis and chronic right ventricular overloading

SummaryThe incidence of double nuclei in myocarditis and in cases with right ventricular overloading (CRVO) was histopathologically assessed in a minimum of 100 longitudinally cut myocytes in specimens obtained at right ventricular endomyocardial biopsy. In myocarditis, the incidence of double nuclei was shown to be 5.8 ± 1.8 and in CRVO and in normal heart tissue it was seen in 3.0 ± 0.8 and 3.2 ± 0.9% (m±S.D.), respectively, of the population of myocytes. It is concluded that double nuclei result from either the activity or the reparative process of myocarditis and that it is not the expression of chronic right ventricular overloading. It is suggested that quantitative assessment of the frequency of double nuclei is an useful method in the interpretation of myocardial biopsy.