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F Terasaki

Publications and source records attributed to F Terasaki.

32 records · Page 2Linked to original sources
PubMed1995

Effect of sulfo-N-succinimidyl palmitate on the rat heart: myocardial long-chain fatty acid uptake and cardiac hypertrophy.

Abnormal long-chain fatty acid metabolism has been suggested as having a role in the genesis of certain cardiac diseases, and depressed myocardial long-chain fatty acid uptake has been clinically demonstrated in some patients with hypertrophic cardiomyopathy. However, the site where long-chain fatty acid metabolism is affected in cardiomyopathy remains unclear. Although cardiac hypertrophy is reported to be induced in rats by a fat-free diet, little is known of the consequences of depressed myocardial long-chain fatty acid uptake. Sulfo-N-succinimidyl derivatives of long-chain fatty acids have been shown to irreversibly inhibit long-chain fatty acid transport. To investigate the possible linkage of abnormal long-chain fatty acid uptake with cardiac hypertrophy, myocardial long-chain fatty acid uptake was blocked in rats using a sulfo-N-succinimidyl derivative of palmitate (SSP). SSP was intraperitoneally administered to rats for 12 weeks, and its effects on physiological parameters, and cardiac morphology were studied, SSP treatment (20 mg/kg) caused a 12% increase in heart weight (663.7 +/- 33.6 mg in controls v 741.2 +/- 26.5 mg after SSP treatment) and an 11% increase in the heart weight to body weight ratio (2.46 +/- 0.10 in controls v 2.72 +/- 0.17 after SSP) without any significant change of body weight. No significant differences were observed in blood pressure, heart rate, and serum hormones (insulin and triiodothyronine) between the control and SSP-treated groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Analysis of Variance↗
PubMed1993

Histological organization of the right and left atrioventricular valves of the chicken heart and their relationship to the atrioventricular Purkinje ring and the middle bundle branch.

In the avian heart the right and left atrioventricular (AV) valves not only exhibit their own special anatomical characteristics, but they also are in close proximity to the conduction system. The right AV valve is a single, spiral plane of myocardium, in remarkable contrast to the fibrous structure characteristic of the mammalian tricuspid valve. A ring of Purkinje tissue encircles the avian right AV orifice and connects to the muscular valve. The chicken has no crista supraventricularis, its right AV valve serving that function as well as opening and closing the right AV orifice. The left AV valve consists of three leaflets instead of the two typical of mammalian hearts. Its anterior and posterior leaflets are small; its large aortic (medial) leaflet merges with the bases of both the left and noncoronary cusps of the aortic valve by fibrous tissue, resembling that of the mammalian heart. However, unlike in mammals, there is a slim cylinder of continuous myocardium coursing parallel to this fibrous junction. This unusual arc of myocardium in the chicken serves to complete an entire subaortic ring of myocardium and is thus potentially capable of constricting the outflow tract of the chicken's left ventricle. The middle bundle branch connects with both the muscle arch and the AV Purkinje ring. Thus the myocardium in or near both AV valves (and the left ventricular outflow tract) in the chicken heart is so arranged that it may receive direct early activation from the conduction system.

Animals↗
PubMed1993

Cardiac conduction system in the chicken: gross anatomy plus light and electron microscopy.

Twenty-three chicken hearts were used to study the cardiac conduction system by light and electron microscopy. In addition to a sinus node, atrioventricular node (AVN), His bundle, left and right bundle branches (LBB, RBB), the chicken also has an AV Purkinje ring and a special middle bundle branch (MBB). The sinus node lies near the base of the lower portion of the right sinoatrial valve. The AV node is just above the tricuspid valve and anterior to the coronary sinus. The His bundle descends from the anterior and inferior margin of the AV node into the interventricular septum, then dividing into right, left and middle branches some distance below the septal crest. The middle bundle branch turns posteriorly toward the root of the aorta. The AV Purkinje ring originates from the proximal AV node and then encircles the right AV orifice, joining the MBB to form a figure-of-eight loop. The chicken conduction system contains four types of myocytes: 1) The P cell is small and rounded, with a relatively large nucleus and sparse myofibrils. 2) The transitional cell is slender and full of myofibrils. 3) The Purkinje-like cell resembles the typical Purkinje cell, but is smaller and darker. 4) The Purkinje cell is found in the His bundle, its branches, and the periarterial and subendocardial Purkinje network.

Animals↗
PubMed1993

Electron microscopic demonstration of intercellular junctions between subendocardial smooth muscle and myocardium in the sheep heart.

The eustachian ridge of 11 sheep hearts was examined by light and electron microscopy to elucidate the morphologic relationship between cardiac smooth muscle cells and myocardial cells. Smooth muscle cells were commonly observed in the subendocardial connective tissue and they were usually arranged in strands. When mixed with myocardial cells at the margin of these strands, smooth muscle cells exhibited numerous direct connections with the myocardial cells. These intercellular junctions were composed primarily of simple appositions (undifferentiated regions), but occasional desmosomes and fasciae adherents (intermediate junctions) were seen. We found no nexus (gap junctions) at these sites. The existence of direct intercellular junctions between smooth muscle and myocardium suggests several possible electrical and mechanical interactions.

Animals↗
PubMed1993

Apoptosis and pleomorphic micromitochondriosis in the sinus nodes surgically excised from five patients with the long QT syndrome.

Sinus nodes of five symptomatic patients with the long QT syndrome were surgically excised and followed by permanent electronic pacing as part of a new surgical treatment. We examined those sinus nodes by light and electron microscopy with tissue that was promptly fixed at the time of surgery. All five sinus nodes were similarly abnormal. By light microscopy we found distinctive focal fibrosis, some degenerating myocytes and neural elements, and numerous narrowed small vessels. Except in the nerves there was no evidence of inflammation. In electron micrographs the mitochondria within nodal myocytes were abnormally abundant, remarkably pleomorphic, and smaller than those in normal human sinus nodal cells. The ultrastructural features of the degenerated nodal cells were typical of apoptosis, characterized by the absence of inflammation, well-preserved mitochondria, the presence of apoptotic bodies, phagocytosis of these cells by neighboring myocytes, and especially in smooth muscle cells of arterioles, nuclear chromatin margination and nucleolar disintegration. Apoptotic degeneration of nodal myocytes was stochastic, with adjacent cells appearing unaffected. Focal ischemia caused by narrowed vessels may be a contributory factor, and the nerves may harbor some viral infection, but for the nodal myocytes the abnormality appears to be primarily apoptosis, sometimes called programmed cell death. Both the typically episodic clinical features and the terminal event in fatal cases of the long QT syndrome may be due to apoptosis.

Adolescent↗
PubMed1992

Ultrastructural alterations of the conduction system in mice exhibiting sinus arrest or heart block during Coxsackievirus B3 acute myocarditis.

By light and electron microscopy we studied the sinus nodes and atrioventricular (AV) conducting tissue of six C3H/He mice having coxsackievirus B3 acute myocarditis. Sinus arrest was documented in all six mice, and second- or third-degree AV block was documented in three of the six mice. Although myocarditic changes in the conduction system, especially in the sinus node, were less than those in atrial and ventricular working myocardium, there were distinct abnormalities within both the sinus node and AV conducting tissue in all six hearts. Important ultrastructural alterations were inflammatory cell infiltrates and significant injury of specialized cells and of neural tissue. Specialized cells showed various features of degeneration and necrosis. Neural tissue damage included degeneration of axons and Schwann cells and disorganization of the neuromuscular junctions. Inflammatory cells, particularly macrophages, were often in intimate contact with injured specialized cells and neural tissue. Interstitial edema and bleeding and lymphatic vessel dilatation were also observed. These pathologic changes are considered to play an important role in the development of the documented disturbances of rhythm and conduction.

Animals↗
PubMed1992

Comparative ultrastructure of the tip of ventricular papillary muscle.

Electron microscopic studies of the tips of left ventricular papillary muscles from seven human, two monkey, three sheep, and two chicken hearts were done to elucidate the fine structure of myotendinous junctions. The human specimens were from normal hearts obtained 3 to 9 hours postmortem from persons aged 7 months to 30 years (mean, 13.3 years). We found no significant ultrastructural differences between the human hearts and those of monkey, sheep, and chicken. Myocardial fibers were elongated and thinner (tapered) in the tips of papillary muscles. In addition to usual working myocardial cells, the distal end of narrowing muscle fibers also contained small pale cardiocytes containing fewer myofibrils and smaller mitochondria. These cells were similar to P cells or transitional cells in the conduction system. Nerve axons and Schwann cells were commonly seen in the interstitium, usually in association with capillaries. Fibroblasts and axon varicosities were occasionally seen extremely close to the cardiocytes. These specialized myocardial cells associated with rich neural tissue in the papillary muscle tip possibly function as foci of local automaticity. This histologic organization may also represent neurosensory function responding to and monitoring local pressure changes, efferent adrenergic or cholinergic neural activity, or both.

Adolescent↗
PubMed1990

Arrhythmias in Coxsackie B3 virus myocarditis. Continuous electrocardiography in conscious mice and histopathology of the heart with special reference to the conduction system.

In patients with acute myocarditis, arrhythmias constitute one of the crucial risk factors for morbidity and mortality. To clarify the incidences and the chronological features of arrhythmias and their correlation with the histopathology of the heart, we conducted continuous electrocardiography in an animal model of viral myocarditis, and light microscopy of the heart with special reference to the conduction system. Forty weanling C3H/He mice were divided into an inoculated group (IG) and a control group (CG), of 20 mice each. IG was injected intraperitoneally with coxsackie B3 virus and CG was injected with virus-free culture medium. Thin electrodes were implanted in their chest walls and connected with an electric impulse transmitting device so that they could move freely. ECGs were recorded continuously without anesthesia up to the 14th postinoculation day. The atrial and ventricular myocardium and the conduction system were studied by light microscopy. In CG, no arrhythmia was noted. In IG, various kinds of arrhythmias were documented. The incidences of the arrhythmia in the 20 mice were: sinus arrest 80%, second or third degree atrioventricular (AV) block 30%, premature atrial complexes 30%, premature ventricular complexes 20%, and ventricular tachycardia 10%. Arrhythmias were usually transient and recurrent, and the majority of them developed between the 6th and 13th day, when the histologic changes of the heart were greatest. There seemed to be a correlation between the kind of arrhythmias and the myocarditic lesions. Mice with sinus arrest or AV block developed histopathologic changes in the sinus node or AV conducting tissue, respectively. In the early stage of myocarditis, no inflammatory changes were apparent in the sinus node in the mice with sinus arrest.

Animals↗
PubMedDate not supplied

Backscattered electron imaging: A new method for the study of cardiomyocyte architecture using scanning electron microscopy.

Scanning electron microscopy (SEM) with secondary electron emissions is useful for the study of cardiomyocyte architecture, however, the information is limited from the cell surface. Whereas backscattered electron (BSE) emission can give a high-resolution image of the specimen's intracellular structure after heavy metal staining. In this study, we applied BSE imaging analysis to the study of the arrangement of cardiomyocytes in the myocardium. The tissue specimens from a normal fresh monkey heart, normal human heart obtained at autopsy, and surgically resected tissue from a patient with old myocardial infarction in the left ventricular aneurysmectomy were used. The tissue specimens were fixed in neutral formalin, treated with NaOH and then stained with Gomori's silver methenamine reagent followed by tannic acid and osmium tetroxide. After dehydration and drying, the specimens were coated with carbon and examined by SEM with a BSE detector. In the tissue preparations, the A bands of sarcomeres were selectively stained with silver so that the arrangements of subsarcolemmal myofibrils and the intercalated discs were clearly seen in the BSE images. In the left ventricular aneurysmal walls of old myocardial infarction, atrophied cardiomyocytes with disarray of subsarcolemmal myofibrils were observed. The results strongly suggest that BSE images are further applicable to the study of the architecture of cardiac myocytes and their branches, and the arrangement of intracellular myofibrils in various diseased myocardium.

Animals↗
PubMedDate not supplied

Myocardial inflammatory cell infiltrates in cases of dilated cardiomyopathy: light microscopic, immunohistochemical, and virological analyses of myocardium specimens obtained by partial left ventriculectomy.

OBJECTIVE: Partial left ventriculectomy was introduced for the treatment of refractory dilated cardiomyopathy (DCM). To determine the presence and degree of inflammatory cell infiltrates in DCM and the correlation between the underlying myocardial injury and early clinical outcomes after the operation, we performed histopathological, immunohistochemical, and virological studies of the resected myocardium. METHODS: Posterolateral walls of the left ventricle from 13 idiopathic DCM patients (9 males and 4 females; mean age = 53+/-14 years) were examined. Qualitative and quantitative analyses of the interstitial fibrosis and of the infiltrating inflammatory cells were conducted. For the immunohistochemistry, leukocyte surface markers and antibodies to adhesion molecules and cytokines were used. The histopathological findings were compared with the clinical results, including outcome within 1 year, and pre- and postoperative hemodynamic data. Genomic analysis of the myocardium with polymerase chain reaction was performed for enterovirus, mumps, influenza A, cytomegalovirus, and hepatitis C virus. RESULTS: (1) The three patients who died of cardiac insufficiency after surgery had a higher count of infiltrating inflammatory cells than the eight survivors (32.1+/-10.4 vs 16.3+/-11.9 cells/mm2, p = 0.07). The severity of interstitial fibrosis (percent fibrosis) did not differ significantly between these two groups (28.3+/-15.0 vs 24.0+/-11.7%). (2) In patients who died of myocardial dysfunction, focal accumulations of lymphocytes were common, in which cytotoxic/suppressor T cells and helper/inducer T cells were observed. (3) Enterovirus genome was detected in the myocardium of two patients, both of them died after surgery. CONCLUSIONS: Inflammatory cell infiltrates or active myocarditis appear in some cases to play an important role in the etiology and pathophysiology of clinically diagnosed DCM. There is a possibility that those patients with a more severe or ongoing inflammatory process might have poor outcomes after partial left ventriculectomy.

Adult↗
PubMedDate not supplied

Enterovirus RNA replication in cases of dilated cardiomyopathy: light microscopic in situ hybridization and virological analyses of myocardial specimens obtained at partial left ventriculectomy.

OBJECTIVE: Recently, attention has been focused on enteroviral infection of the heart in the genesis of dilated cardiomyopathy (DCM). To determine the location of enteroviral RNA in the myocardium, we performed light microscopic in situ hybridization (ISH) and virological analyses of myocardial specimens obtained at partial left ventriculectomy (PLV). METHODS: Posterolateral walls of the left ventricle from 26 DCM patients were examined. Myocardial specimens were tested for the presence of enteroviral genomes by polymerase chain reaction (PCR). We selected two age-matched groups (10 patients each) in which enteroviruses were either present (EV-plus group) or not (EV-minus group). For both groups, we examined in situ localization of enteroviral RNA in the myocardium by ISH. RESULTS: In PCR studies, both sense and antisense enteroviral RNA were detected in the myocardium of seven patients in the EV-plus group. The presence of this RNA indicates active viral replication in the myocardium. Five of seven patients who exhibited both sense and antisense enteroviral RNA died early after surgery. On ISH, three patients had evidence of active replication of enteroviral genomes. Viral genomes were present in myocardial lesions, especially in endocardial sites. Viral signals were found in degenerating myocardial cells, interstitial inflammatory cells, and endothelial cells of small vessels. These positive signals were not detected in the myocardium of the EV-negative group. CONCLUSIONS: We detected both sense and antisense enteroviral RNA in various myocardial lesions. This suggests that active enteroviral replication plays a role in the development of myocardial lesions in DCM patients. Active viral replication appears to be a prognostic factor for DCM after PLV. Further study of active viral replication in myocardial lesions will provide information useful for evaluating different therapeutic strategies for DCM.

Adolescent↗