Ultrastructural and immunohistochemical studies on myocardial biopsies from a patient with eosinophilic endomyocarditis

Right ventricular endomyocardial biopsy specimens from a 13-year-old boy with hypereosinophilia were studied by light and electron microscopy using the EG2 monoclonal antibody, which recognizes a common epitope of eosinophil cationic protein and eosinophil protein-X. Although the endocardial layer was of normal thickness, many eosinophils, mononuclear cells, and free eosinophil granules were observed in the endocardium and in the vicinity of degenerated myocardial cells. Under electron microscopy, many of the specific granules in and out of eosinophils had lost their crystalloid internae and displayed reversed density, and there were many degranulated eosinophils with reduced number of granules. Immunohistochemically, large amounts of eosinophil cationic protein and protein-X were observed within cardiocytes when many of them were degenerated. Deposits of the proteins were also found in some small vessels. On electron microscopy, accumulations of gold particles, which bind to eosinophil cationic protein and protein-X, were seen in association with specific granules and on the myofilaments in both degenerated and normal-appearing cardiocytes. The presence of eosinophil cationic proteins within cardiocytes may play an important role in the pathogenesis of eosinophilic endomyocardial disease.

Increased digitalis-like immunoreactive substances in neonatal plasma measured using fluorescence polarization immunoassay

OBJECTIVE

To better define the reported increased digitalis-like immunoreactive substances (DLIS) in neonatal plasma, we studied the relation among plasma DLIS level, blank intensity (BLK-I) value at FPIA measurement and plasma total bilirubin level.

METHODS

The DLIS levels were measured in 10 neonates with or without jaundice and 10 infants in good health, using fluorescence polarization immunoassay (FPIA) and microparticle enzyme immunoassay (MEIA). BLK-I value and plasma total bilirubin level were also measured simultaneously.

RESULTS

In neonates with jaundice, DLIS using FPIA, BLK-I and total bilirubin level were 0.58 +/-0.13 ng/mL, 2598 +/- 408, and 17.98 +/- 1.13 mg/dL, respectively, before phototherapy, and 0.33 +/-0.06 ng/mL, 1886 +/- 237, and 15.16 +/- 2.07 mg/dL after phototherapy. Corresponding values in neonates without jaundice were (DLIS: 0.34 +/-0.04 ng/mL; BLK-I: 1,764 +/- 278; total bilirubin: 10.37 +/- 4.54 mg/dL); in healthy infants (0.12 +/-0.06 ng/mL, 400.7 +/- 4.6 and 0.42 +/- 0.13 mg/dL, respectively) and in healthy volunteers (0.10 +/-0.07 ng/mL, 403.1 +/- 8.4, and 0.58 +/- 0.30 mg/dL, respectively). Using MEIA, DLIS was not detected in 10 neonates, 10 infants and 20 healthy volunteers.

CONCLUSIONS

A fluorescent compound related to bilirubin increased the BLK-I value in the measurement of neonatal plasma using FPIA. The fluorescence was not the result of endogenous digitalis-like factors.

Angiotensin II receptor blockade prevents microangiopathy and preserves diastolic function in the diabetic rat heart

BACKGROUND

Cardiac microangiopathy may be involved in the development of heart failure in diabetes mellitus.

OBJECTIVE

To evaluate the effect of angiotensin II receptor blockade on cardiac function and fine structures in diabetes.

METHODS

Male Otsuka Long-Evans Tokushima Fatty (OLETF) rats (n = 30), a model of spontaneously developing diabetes mellitus, and their diabetes resistant counterparts (n = 20) were used. At 30 weeks of age, when the OLETF rats show hyperglycaemic obesity with hyperinsulinaemia, the animals were divided into two groups and given candesartan, an angiotensin II receptor blocker, 0.2 mg/kg/day, or vehicle for six weeks. Capillary density was evaluated in the left ventricular myocardium by electron microscopy, matrix metalloproteinase (MMP) activity by zymography, and cytokines by reverse transcriptase polymerase chain reaction.

RESULTS

Compared with the control rats, the OLETF rats at 36 weeks showed decreased peak negative dP/dt (mean (SD): 2350 (250) v 3492 (286) mm Hg/s) and increased cardiomyocyte diameter (24.3 (0.6) v 18.9 (0.6) microm) (both p < 0.05). Thickening of the capillary basement membranes and decreased capillary density were observed. Angiotensin receptor blockade improved almost all the haemodynamic variables, and the histological findings became similar to those of the controls. Angiotensin receptor blockade also activated MMP-2 and prevented an increase of inflammatory cytokines, especially interleukin (IL)-1beta and IL-6, in the diabetic heart.

CONCLUSIONS

Angiotensin II receptor blockade preserved left ventricular diastolic function. It was also potent at improving cardiomyocyte diameter and the thickening of the capillary basement membrane, increasing MMP-2 activity, and decreasing inflammatory cytokines. With all these changes, candesartan could contribute to cardioprotection in diabetes mellitus.

Coxsackie B virus infection in idiopathic dilated cardiomyopathy: clinical and pharmacological implications

Idiopathic dilated cardiomyopathy (IDC) is a myocardial disease characterised by ventricular dilatation, impaired contractility, and the symptoms of congestive heart failure. Although the causes of IDC remain uncertain, much interest has been focused on the enteroviral infection in the myocardium in the pathogenesis of this disease. Enteroviral RNA has been demonstrated in the myocardium at all stages of IDC. Recent studies using sequence analysis of enteroviral polymerase chain reaction (PCR) products have shown that the viruses detected in hearts of patients with IDC are coxsackie B. In addition, active coxsackieviral RNA replication in the myocardium has been demonstrated by strand-specific detection of viral RNA. Viral antigen has also been found in hearts with IDC by immunohistochemical techniques. In tissue culture experiments and transgenic mice, it has been shown that restricted coxsackieviral RNA replication, and not infectious virus progeny, in the myocardium can impair cardiac contractile function and lead to dilated cardiomyopathy. Coxsackieviral RNA in the myocardium can be a marker of a poor clinical outcome after partial left ventriculectomy, and might influence prognosis after heart transplantation. Therefore, there is a therapeutic need to detect replicating coxsackieviral RNA in the myocardium, and a specific therapy for coxsackie B viruses is indicated in the management of patients with virus-positive IDC.

Autophagic degeneration as a possible mechanism of myocardial cell death in dilated cardiomyopathy

In failing hearts, cardiomyocytes degenerate and interstitial fibrosis, which indicates cardiomyocyte loss, becomes more prominent in the myocardium. However, the precise mechanism of cardiomyocyte degeneration that leads to cell death is still unclear, although it is presumed that lysosomal function and autophagy play an important role because lysosomal activity increases under stress such as hypoxia. Myocardium that had been resected during partial left ventriculectomy performed in patients with dilated cardiomyopathy (DCM) was examined. Under light microscopy, some cardiomyocytes had a marked scarcity of myofibrils and had prominent cytoplasmic vacuolization. Atrophic and degenerated cardiomyocytes were often observed adjacent to replacement fibrotic tissue. Immunohistochemistry showed positivity for lysosome-associated membrane protein and a lysosomal catheptic enzyme in vacuoles of various sizes in the cardiomyocytes and these lysosomal markers were markedly increased in atrophic and degenerated cardiomyocytes. Electron microscopy revealed that degenerated cardiomyocytes had many vacuoles containing intracellular organelles, such as mitochondria, and were considered to be autophagic vacuoles. In DCM hearts, autophagy appeared to be associated not only with degradation of damaged intracellular organelles but also with progressive destruction of cardiomyocytes. It is possible that autophagic degeneration is one of the mechanisms of myocardial cell death.

Role of transesophageal echocardiography in the prediction of thromboembolism in patients with chronic nonvalvular atrial fibrillation

The purpose of this study was to determine whether parameters derived from transesophageal echocardiography (TEE) could predict thromboembolism in patients with chronic nonvalvular atrial fibrillation (AF). Eighty-nine patients, mean age 66+/-9 years, who underwent TEE in 1996 to 1999 were studied. The clinical endpoint was a thromboembolic event, including transient ischemic attack (TIA). Sixty-seven patients (75%) were anticoagulated with warfarin after TEE. After a follow-up period of 29+/-10 months, 1 patient died suddenly, 4 had a thromboembolism, and 3 had a TIA; the annual embolic event rate was 3.3%. Left atrial appendage (LAA) thrombus (86% vs 17%, p<0.001), LAA dysfunction (LAA velocity <20 cm/s; 71% vs 25%, p=0.009), and severe LA spontaneous echo contrast (29% vs 2%, p=0.002) were more prevalent in patients with an embolic event than in those without. In patients with LAA thrombus, the annual event rate was 11% as compared with 1.2% in those without (p=0.004). On the Cox proportional hazards model analysis, LAA thrombus (chi-square 7.0, p=0.008), severe LA spontaneous echo contrast (chi-square 7.0, p=0.008), and LAA dysfunction (chi-square 5.9, p=0.015) were significantly related to thromboembolism. Multivariate analysis revealed that LAA thrombus (chi-square 5.5, p=0.019) and LAA dysfunction (chi-square 4.0, p=0.045) were the independent predictors. In conclusion, TEE parameters, particularly the presence of LAA thrombus, can be used to assess thromboembolic potential in patients with chronic nonvalvular AF.

Myocardial inflammatory cell infiltrates in cases of dilated cardiomyopathy as a determinant of outcome following partial left ventriculectomy

Partial left ventriculectomy (PLV) can be used to treat refractory congestive heart failure caused by dilated cardiomyopathy (DCM). In order to understand the relationship between the underlying myocardial injury and early clinical outcomes after PLV, histopathologic, immunohistochemical and virologic studies of the resected myocardium were performed. The posterolateral left ventricular walls from 27 patients with idiopathic DCM were examined. Cardiomyocyte diameter, degree of myocardial fibrosis, degree of cardiomyocyte degeneration, and degree of inflammatory cell infiltration were compared with mortality rates. Polymerase chain reaction was performed to detect enterovirus genome in the myocardium. Some patients had inflammatory cell infiltrates with focal accumulations of lymphocytes and macrophages, including both cytotoxic/suppressor T-cells and helper/inducer T-cells. The number of inflammatory cells (activated lymphocytes plus macrophages/mm2) was significantly greater in patients who died of cardiac insufficiency after surgery (27.8 +/- 5.7; n = 7) than in the survivors (11.1 +/- 2.5; n = 15). There was no significant difference in the degree of myocardial fibrosis, cardiomyocyte diameter or degree of cardiomyocyte degeneration between the 2 groups. Enterovirus genome was detected in the myocardium of 9 (38%) of 24 patients examined and 5 of these enterovirus-positive hearts had severe inflammatory cell infiltrates (37.9 +/- 2.5/mm2). Early survival in patients undergoing PLV for DCM is significantly affected by the degree of myocardial inflammation, so patients with more severe or ongoing inflammation may have poor clinical outcomes. Chronic myocarditis may play an important role in the etiology and pathophysiology of idiopathic DCM.

A case of cardiomyopathy showing progression from the hypertrophic to the dilated form: association of Mt8348A-->G mutation in the mitochondrial tRNA(Lys) gene with severe ultrastructural alterations of mitochondria in cardiomyocytes

This report describes a case of cardiomyopathy with a novel point mutation of mitochondrial DNA coding lysine tRNA in association with severe ultrastructural alterations of the mitochondria in the cardiomyocytes. Abnormalities of energy production and/or abnormal protein synthesis because of the mutation of mitochondrial DNA may have played an important role in the pathogenesis of this case, which showed severe cardiomyocyte degeneration and deterioration from hypertrophic cardiomyopathy to severe dilated cardiomyopathy.

Quantification of left atrial appendage spontaneous echo contrast in patients with chronic nonalvular atrial fibrillation

OBJECTIVES

The left atrial (LA) appendage is the most common site of thrombus formation in patients with atrial fibrillation, and integrated backscatter allows the quantiative assessment of LA spontaneous echo contrast (SEC). Integrated backscatter was used to examine the significance of measuring appendage SEC, specifically in relation to echocardiographic variables implying thromboembolism, in patients with chronic nonvalvular atrial fibrillation.

METHODS

Fifty-two patients with chronic nonvalvular atrial fibrillation and no prior anticoagulant therapy (35 men, 17 women, mean age 66 +/- 7 years) underwent transesophageal echocardiography with integrated backscatter analysis. The LA and LA appendage integrated backscatter intensity were measured with the regions of interest placed in the LA cavity and the appendage, respectively. The integrated backscatter intensity values for these two chambers (corrected "LA" and "LA appendage" integrated backscatter intensity, respectively) were corrected using values from the left ventricular cavity.

RESULTS

The LA appendage integrated backscatter intensity values were available in 44 patients (85%). Overall, the corrected LA appendage integrated backscatter intensity was significantly increased compared with the corrected LA integrated backscatter intensity (2.8 +/- 2.2 vs 2.0 +/- 1.8 dB, p < 0.001). The corrected LA appendage integrated backscatter intensity was inversely correlated with the LA appendage velocity (r = -0.37, p < 0.05), but not with the LA dimension, appendage size, or left ventricular function. The corrected appendage integrated backscatter intensity (4.5 +/- 2.3 vs 2.4 +/- 1.9 dB, p < 0.01) and LA integrated backscatter intensity (3.2 +/- 2.1 vs 1.7 +/- 1.7 dB, p < 0.05) were higher in patients who had LA appendage thrombus (n = 8) than those who did not. With the corrected appendage integrated backscatter intensity set at > or = 2.5 dB, the sensitivity for the presence of appendage thrombus was 88% and the specificity was 64%.

CONCLUSIONS

Patients with chronic nonvalvular atrial fibrillation had a denser SEC in the LA appendage compared with SEC in the main LA cavity. The severity of the appendage SEC was influenced by the LA appendage function rather than its size. Quantification of SEC in the appendage, rather than main LA cavity, was more valuable for assessing embolic potential.

Development of a simple whole blood panel test for detection of human heart-type fatty acid-binding protein

OBJECTIVE

For the diagnosis of acute myocardial infarction (AMI), we have developed a rapid and simple whole blood panel test for the detection of human heart-type fatty acid-binding protein (H-FABP) using one-step immunochromatography.

METHODS AND RESULTS

We have developed a whole blood panel test for rapid detection of human H-FABP using a one-step immunochromatography technique. The result of this panel test was not affected by the other contents of the blood such as bilirubin, hemoglobin and others. Furthermore, no cross-reactivity of the antibodies was found with other cardiac markers or other tissue-type FABPs. The result of this panel test was similar to the diagnostic cut-off value, 6.2 ng of H-FABP per mL of serum which was evaluated by the enzyme-linked immunosorbent assay (ELISA).

CONCLUSION

We have developed a simple one-step immunochromatography technique to detect H-FABP in whole blood sample. Further studies are required to identify the value of this point-of-care testing (POCT) as a diagnostic marker for AMI.

Peflin and ALG-2, members of the penta-EF-hand protein family, form a heterodimer that dissociates in a Ca2+-dependent manner

Peflin, a newly identified 30-kDa Ca(2+)-binding protein, belongs to the penta-EF-hand (PEF) protein family, which includes the calpain small subunit, sorcin, grancalcin, and ALG-2 (apoptosis-linked gene 2). We prepared a monoclonal antibody against human peflin. The antibody immunoprecipitated a 22-kDa protein as well as the 30-kDa protein from the lysate of Jurkat cells. Western blotting of the immunoprecipitates revealed that the 22-kDa protein corresponds to ALG-2. This was confirmed by Western blotting of the immunoprecipitates of epitope-tagged peflin or ALG-2 whose cDNA expression constructs were transfected to human embryonic kidney (HEK) 293 cells. Gel filtration of the cytosolic fraction of Jurkat cells revealed co-elution of peflin and ALG-2 in fractions eluting earlier than recombinant ALG-2, further supporting the notion of heterodimerization of the two PEF proteins. Surprisingly, peflin dissociated from ALG-2 in the presence of Ca(2+). Peflin and ALG-2 co-localized in the cytoplasm, but ALG-2 was also detected in the nuclei as revealed by immunofluorescent staining and subcellular fractionation. Peflin was recovered in the cytosolic fraction in the absence of Ca(2+) but in the membrane/cytoskeletal fraction in the presence of Ca(2+). These results suggest that peflin has features common to those of other PEF proteins (dimerization and translocation to membranes) and may modulate the function of ALG-2 in Ca(2+) signaling.

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.

Evaluation of viral infection in the myocardium of patients with idiopathic dilated cardiomyopathy

OBJECTIVES

The aim of this study was to evaluate the viral etiology of idiopathic dilated cardiomyopathy (DCM).

BACKGROUND

The demonstration of enteroviral genome in hearts with DCM has reinforced the importance of enteroviruses in the pathogenesis of DCM. However, there is uncertainty about the character and activity of enteroviruses detected in the myocardium. Recently, the association of hepatitis C virus or adenovirus with DCM has been reported.

METHODS

Myocardial specimens from 26 patients with idiopathic DCM, which were obtained at partial left ventriculectomy (PLV), were examined virologically. Strand-specific detection of enteroviral RNA was performed to differentiate active viral replication from latent persistence. Polymerase chain reaction was used to detect genomic sequences of hepatitis C virus, adenovirus, cytomegalovirus, influenza viruses, mumps virus, herpes simplex viruses, varicella-zoster virus and Epstein-Barr virus.

RESULTS

Plus-strand enteroviral RNA was detected in 9 (35%) of the 26 patients. Minus-strand enteroviral RNA was determined in seven (78%) of these nine plus-strand RNA-positive patients. Sequence analysis revealed that the enteroviruses detected were coxsackie B viruses, such as coxsackievirus B3 and B4. However, genetic material from other viruses was not detected. Six (86%) of seven minus-strand enteroviral RNA-positive patients died of cardiac insufficiency within the first six months after PLV.

CONCLUSIONS

Coxsackie B viruses were seen in hearts with idiopathic DCM. Active viral RNA replication appeared to be present in a significant proportion of these cases. Minus-strand coxsackieviral RNA in the myocardium can be a marker for poor clinical outcome after PLV. There was no evidence of persistent infection by other viruses in hearts with DCM.

Integrated backscatter assessment of left atrial spontaneous echo contrast in chronic nonvalvular atrial fibrillation: relation with clinical and echocardiographic parameters

Integrated backscatter (IB) provides the quantitative assessment of left atrial spontaneous echo contrast (SEC). The IB intensity of the left atrial cavity relative to the left ventricular cavity is related to atrial thrombus in patients with atrial fibrillation (AF) or sinus rhythm. However, little is known about the relation between the quantitative SEC value of the left atrial cavity and variables implying thromboembolism in nonvalvular AF. To examine this relation, we performed transesophageal echo-cardiography with IB analysis in 65 patients with chronic nonvalvular AF. The quantitative SEC value of the left atrial cavity was defined as the difference between atrial IB intensity and ventricular IB intensity (corrected IB intensity). The corrected IB intensity was correlated with the left atrial dimension (r = 0.25, P =.049), the left atrial appendage velocity (r = -0.41, P <.001), and the duration of AF (r = 0.23, P =. 023). The corrected IB intensity was higher in patients who had a history of hypertension (3.2 +/- 2.2 dB versus 2.0 +/- 1.6 dB, P =. 018), SEC (3.9 +/- 1.9 dB versus 1.4 +/- 1.1 dB, P =.002), and left atrial thrombus (4.5 +/- 2.7 dB versus 2.2 +/- 1.7 dB, P <.001) when compared with those who did not have these abnormalities. The corrected IB intensity was significantly lower in patients with significant mitral regurgitation than in those without it (1.1 +/- 1. 2 dB versus 2.7 +/- 2.0 dB, P =.036). When the cutoff value of the corrected IB intensity was set at >/=2.0 dB, the sensitivity for left atrial thrombus was 78% and the specificity was 55%. In patients with chronic nonvalvular AF, the quantitative SEC value of the left atrial cavity depends on the duration of AF as well as the left atrial dimension and appendage velocity. Although IB may be capable of identifying patients with higher risk of cardiogenic embolism, a large-scale prospective study is needed to actually establish this.

Nitric oxide mediates inhibitory effect of losartan on angiotensin-induced contractions in hamster but not rat aorta

We investigated a possible contribution of nitric oxide (NO) and prostaglandins to the inhibitory effect of losartan on contractions to Ang I (10(-6) M) and Ang II (10(-7) M) with or without L-NAME (10(-4) M) or indomethacin (10(-5) M) in the aorta of WKY, SHR and hamster (n=7 each). Rings of thoracic aorta (2-mm long) were placed in a myograph (5 ml). Endothelium-dependent vasodilations were evaluated with acetylcholine (10(-8) to 10(-6) M). After a 45-minute incubation with L-NAME under a resting tension of 2 g, only hamster aorta contracted (p<0.01). The SHR aorta showed impaired relaxations to acetylcholine compared with the WKY and hamster aorta (p<0.05). Despite the difference in the stimulated NO release, losartan completely abolished the responses to Ang I and Ang II both in WKY and SHR vessels irrespective of the presence of L-NAME. In contrast to the rat aorta, the inhibitory effect of losartan was attenuated in the presence of L-NAME in the hamster aorta (78% vs 99% inhibition, p<0.05). Indomethacin did not alter the effect of losartan in any vessels. Our results suggest that the presence of NO, particularly a basal secretion of NO, is necessary for the full expression of the inhibitory effect of losartan in the hamster, but not in WKY or SHR, aorta. Unlike NO, prostaglandins do not appear to play a role in the effect of losartan.

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.

Increased digitalis-like immunoreactive substances in patients with hypertrophic cardiomyopathy

AIMS

Although increased digitalis-like immunoreactive substances have been found in cases of hypertension and heart failure, no information is available about digitalis-like immunoreactive substances in patients with hypertrophic cardiomyopathy. We investigated digitalis-like immunoreactive substances in the plasma and biopsied specimens of patients with hypertrophic cardiomyopathy.

METHODS AND RESULTS

In 40 patients with hypertrophic cardiomyopathy (27 with the non-obstructive type and 13 with the obstructive type), the plasma concentration of digitalis-like immunoreactive substances was studied by fluorescence polarization immunoassay. Right ventricular endomyocardial biopsy specimens were analysed immunohistochemically, using a monoclonal antibody against digoxin. An increase in digitalis-like immunoreactive substances of more than 0.2 ng. ml(-1)in plasma was found in six of 27 patients with non-obstructive hypertrophic cardiomyopathy (22.2%) and five of 13 with obstructive hypertrophic cardiomyopathy (38.4%). Under light microscopy, positive staining against the antibody was observed heterogeneously on some cardiocytes. In non-obstructive hypertrophic cardiomyopathy, digitalis-like immunoreactive substances in the plasma correlated with the left atrial dimension and inversely with the cardiac index. In obstructive hypertrophic cardiomyopathy, plasma and myocardial digitalis-like immunoreactive substances were positively correlated; they also correlated with left ventricular end-diastolic pressures. Under electron microscopy, digitalis-like immunoreactive substances were detected at the sarcolemma in the free wall, T-tubules, intercalated discs and Z-bands of cardiocytes.

CONCLUSIONS

Increased digitalis-like immunoreactive substances in plasma and cardiocytes, which may have been caused by pressure and/or volume overload, were found in patients with hypertrophic cardiomyopathy. Digitalis-like immunoreactive substances may act on the sarcolemma of cardiocytes and be transported into the cytoplasm.

Peflin, a novel member of the five-EF-hand-protein family, is similar to the apoptosis-linked gene 2 (ALG-2) protein but possesses nonapeptide repeats in the N-terminal hydrophobic region

The calpain small subunits of sorcin, grancalcin, and ALG-2 constitute a family of the Ca(2+)-binding proteins with five EF-hand-like motifs (penta-EF-hand domain or PEF domain) in their C-terminal regions and hydrophobic domains with variable lengths in their N-terminal regions. Searching the human DNA data base of expressed sequence tags (EST) revealed novel partial sequences similar to, but distinct from, the sequences of the previously known PEF proteins. We isolated a cDNA clone of near full length by 5'- and 3'-RACE (rapid amplification of cDNA end) methods and compared the predicted amino acid sequence (284 residues) of the novel EF-hand protein, named peflin, with those of known PEF proteins. The PEF domain of peflin is most similar to ALG-2 (40.9% identity) among the family, particularly in EF-1 (46.2%) and EF-3 (57.1%) regions. Peflin has a longer N-terminal hydrophobic domain than any other member of the family, and it contains nine nonapeptide (A/PPGGPYGGP) repeats. Western blot analysis demonstrated that peflin (30 kDa) was expressed in various nonadherent and adherent cultured human cell lines, including Jurkat, HL60, HeLa, and HT1080. Peflin may play basic roles in Ca(2+) signaling irrespective of cell types.

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.

CD36 mediates long-chain fatty acid transport in human myocardium: complete myocardial accumulation defect of radiolabeled long-chain fatty acid analog in subjects with CD36 deficiency

Long-chain fatty acids (LCFA) are the major energy substrate for heart and their oxidation is important for achieving maximal cardiac work. However, the mechanism of uptake of LCFA by myocardium has not been clarified. We previously reported that bovine myocardial LCFA transporter has a sequence homology to human CD36. Clinically, total defect of myocardial uptake of radiolabeled long-chain fatty acid analog [123I-BMIPP: Iodine-123 15-(p-iodophenyl)-(R,S)-methylpentadecanoic acid] has been reported in some restricted cases, but the etiology has not been clarified. In the present study, we analyzed CD36 expression and CD36 gene in subjects who showed total lack of myocardial 123I-BMIPP accumulation, and, vice versa, evaluated myocardial 123I-BMIPP uptake in subjects with CD36 deficiency. Four unrelated subjects were evaluated, Two were found to have negative myocardial LCFA accumulation by 123I-BMIPP scintigraphy, after which the expression of CD36 on their platelets and monocytes was analyzed. Remaining two subjects were identified as CD36 deficiency by screening, then 123I-BMIPP scintigraphy was performed. Expression of CD36 on platelets and monocytes was measured by flow cytometric analysis. The molecular defects responsible for CD36 deficiency was detected by allele-specific restriction enzyme analysis. CD36 expression was totally deficient in all 4 subjects on both platelets and monocytes. Two subjects were homozygous for a 478C-->T mutation. One was heterozygous for the dinucleotide deletion of exon V and single nucleotide insertion of exon X, and remaining one was considered to be heterozygous for the dinucleotide deletion of exon V and an unknown gene abnormality. All cases demonstrated a completely negative accumulation of myocardial LCFA despite of normal myocardial perfusion, which was evaluated by thallium scintigraphy. In addition, all cases demonstrated apparently normal hepatic LCFA accumulation Thus, these findings suggested that CD36 acts as a major myocardial specific LCFA transporter in humans.

Calcium-induced exposure of a hydrophobic surface of mouse ALG-2, which is a member of the penta-EF-hand protein family

ALG-2 is a 22 kDa EF-hand type Ca2+-binding protein associated with lymphocyte apoptosis. Comparison of the primary structure of ALG-2 with those of EF-hand type proteins revealed that it belongs to the penta-EF-hand (PEF) protein family including the small subunit of calpain. We established a convenient method for the purification of the recombinant mouse ALG-2 expressed in Escherichia coli. The recombinant protein was first pelleted from a lysate in the absence of a Ca2+-chelator, and then extracted with buffer containing EDTA/EGTA followed by purification by conventional column chromatographies. Estimation of the molecular mass by gel filtration suggested that the recombinant ALG-2 occurred as a monomeric form. Ca2+-dependent precipitation was blocked by inclusion of non-ionic detergent Triton X-100, suggesting hydrophobic self-aggregation at high concentrations of the protein. The N-terminal deletion mutant lacking the hydrophobic non-PEF region was found to be more soluble than the wild type in the presence of Ca2+. Analysis using a fluorescent hydrophobicity probe indicated that ALG-2 exposed a hydrophobic surface in a Ca2+-concentration dependent manner, the half-maximal effect occurring at approximately 6 microM. Mg2+ was not effective for the conformational change. On Western blotting, ALG-2 was detected in particulate fractions from cultured mammalian cells, suggesting the association of the protein with macromolecules in the cells.

A case of malignant lymphoma with diastolic heart failure

In patients with malignant lymphoma, the first signs and symptoms are frequently noncardiac and clinical manifestations of cardiac involvement are often nonspecific. This case report presents a patient with malignant lymphoma whose first manifestation was characteristic of heart failure, mainly due to diastolic dysfunction, and whose postmortem examination revealed massive myocardial invasion.

Regulation of matrix metalloproteinase-9 and inhibition of tumor invasion by the membrane-anchored glycoprotein RECK

A human fibroblast cDNA expression library was screened for cDNA clones giving rise to flat colonies when transfected into v-Ki-ras-transformed NIH 3T3 cells. One such gene, RECK, encodes a membrane-anchored glycoprotein of about 110 kDa with multiple epidermal growth factor-like repeats and serine-protease inhibitor-like domains. While RECK mRNA is expressed in various human tissues and untransformed cells, it is undetectable in tumor-derived cell lines and oncogenically transformed cells. Restored expression of RECK in malignant cells resulted in suppression of invasive activity with concomitant decrease in the secretion of matrix metalloproteinase-9 (MMP-9), a key enzyme involved in tumor invasion and metastasis. Moreover, purified RECK protein was found to bind to, and inhibit the proteolytic activity of, MMP-9. Thus, RECK may link oncogenic signals to tumor invasion and metastasis.

Prosthetic ball valve endocarditis due to Gemella species

A case is presented of endocarditis that was affecting a prosthetic ball valve (Starr-Edwards) and which was caused by Gemella species. A 57-year-old man was admitted with a 3-day history of abdominal pain with fever. At the time of admission, his temperature was 37.7 degrees C and laboratory tests showed elevated inflammatory parameters and an increased neutrophil count. However, transthoracic echocardiogram showed no vegetation. During hospitalization, Gemella spp. were detected by blood culture, and a transesophageal echocardiogram showed vegetation on the prosthetic valve. He was treated with intravenous ampicillin and astromycin, and also underwent valve replacement. This is the first case in Japan of infective endocarditis of a prosthetic valve due to Gemella spp.

Spontaneous myocarditis in DBA/2 mice. Light microscopic study with transmission and X-ray analytical electron microscopic studies

DBA/2 inbred mice spontaneously develop myocarditis and a unique form of subepicardial inflammation of the right ventricle characterized by a prominent eosinophilic infiltrate with calcinosis. We studied this myocarditis using light microscopy and both transmission and analytical X-ray electron microscopy, paying particular attention to eosinophil-associated cardiocyte injury. At 5 weeks of age, many eosinophils and mononuclear cells (MNCs) were seen in the subepicardium of the right ventricle. Electron microscopy showed that cardiocytes underwent degenerative changes, including myofibrillar lysis, accumulation of Z-band material and mitochondrial inclusions, and rupture of plasma membranes. The infiltrating eosinophils appeared to be activated, and cells with cytoplasmic vacuoles, suggestive of degranulation, were noted. The myocardial injury was most severe in the 7th week and healed with myocardial fibrosis and calcinosis by the 8th week. Analytical X-ray electron microscopy showed that the calcinosis was initiated in mitochondrial inclusions of injured cardiocytes. The peripheral eosinophil count did not increase during the course of the disease, but there was a positive correlation between the ratio of eosinophils to infiltrated white blood cells (Eo/WBCs) in the right ventricle and the severity of myocardial damage. Eosinophils may play a significant part in subepicardial cardiocyte injury seen in DBA/2 mice.

Collagen subtypes and matrix metalloproteinase in idiopathic restrictive cardiomyopathy

BACKGROUND

Idiopathic restrictive cardiomyopathy is a rare disease characterized by diastolic dysfunction, and the pathogenesis of the stiff heart remains unclear. The purpose of this study was to analyze the subpopulation of collagen fibers and determine the expression of matrix metalloproteinase in restrictive cardiomyopathy.

METHODS AND RESULTS

In endomyocardial biopsy specimens obtained from seven patients with restrictive cardiomyopathy, collagen fiber types I, III, and IV, and matrix metalloproteinase- and two were observed by light and electron microscopy, using monoclonal antibodies. Type I collagen was less prominent in the interstitium, whereas the immunoreactivity for type III collagen was marked. The immunoreactivity against matrix metalloproteinase-1 was observed along with types I and III collagen fibers and in the cytoplasm of some fibrocytes/fibroblasts. The matrix metalloproteinase-1 tended to increase when the reactivity against types I and III collagen was prominent. Both type IV collagen and matrix metalloproteinase-2 were observed along arterial walls and the basement membrane of cardiocytes.

CONCLUSIONS

Increased type III collagen may play an important role as the cause of left ventricular stiffness in restrictive cardiomyopathy. The matrix metalloproteinase appeared to be involved in a cascade of collagen synthesis and the remodeling of the heart in patients with restrictive cardiomyopathy.

[Clinicopathological features of influenza myocarditis and pericarditis]

Myocarditis is a rare complication of influenza infection but is occasionally fatal. Recent application of percutaneous cardiopulmonary support and/or intraaortic balloon pumping to the serious case of viral myocarditis brought an good prognosis. We should recognize that the patient with viral infection such as influenza may have myocarditis and should make an early diagnosis for adequate treatment in time. To avoid misdiagnosis we must know characteristic symptoms and signs of cardiac involvement during influenza infection.

Intracellular viral localization in murine coxsackievirus-B3 myocarditis. Ultrastructural study by electron microscopic in situ hybridization

Group B Coxsackieviruses are a common cause of myocarditis. To detect the viral genome and its localization in the myocardium, we examined C3H/He mice with Coxsackievirus B3 (CVB3) myocarditis on days 5, 8, and 14 after inoculation by the reverse transcriptase polymerase chain reaction and by in situ hybridization. Sense and antisense CVB3 RNA were detected in the myocardium of all mice up to day 14 by reverse transcriptase polymerase chain reaction. Light microscopic in situ hybridization with a cDNA probe for CVB3 showed clusters of positive signals in the areas of myocardial necrosis and cell infiltration. With electron microscopic in situ hybridization, CVB3 RNA was detected in the cytoplasm of cardiocytes, between the myofibrils, near the mitochondria, and in tubular or vesicular structures. Viral RNA was also detected in necrotic debris, in the cytoplasm of macrophages, and in the cytoplasm of interstitial fibroblasts. These findings suggest that CVB3 RNA is replicated in the cytoplasm of cardiocytes, transferred into tubular or vesicular structures, released into the interstitium, and phagocytosed by macrophages. Some positive signals were also detected in the cytoplasm of cardiocytes showing close contact with infiltrating lymphocytes, suggesting that the lymphocytes recognized virus-infected cardiocytes and caused cell-mediated immune cardiocyte damage.

Evolution to dilated cardiomyopathy from acute eosinophilic pancarditis in Churg-Strauss syndrome

We describe the clinical manifestations of a patient with Churg-Strauss syndrome who presented with severe acute cardiac involvement and whose disease evolved to dilated cardiomyopathy (DCM), with special reference to the histopathological findings. Endomyocardial biopsies, conducted sequentially, three times within 10 months, revealed severe eosinophilic endomyocarditis in the acute phase, interstitial fibrosis in the subacute phase, and endocardial thickening with mural thrombi, at 10 months. Although acute inflammation associated with elevation of eosinophil granule proteins subsided with steroid therapy, left ventricular dilatation with reduced contractility progressed. A subgroup of DCM is not considered to be idiopathic but, rather, an aftereffect of hypereosinophilic heart disease.

Molecular detection and differentiation of enteroviruses in endomyocardial biopsies and pericardial effusions from dilated cardiomyopathy and myocarditis

Enteroviruses (EVs), especially group B coxsackieviruses, have been implicated in the pathogenesis of myocarditis and dilated cardiomyopathy (DCM). To determine whether a specific type of EV is present in DCM hearts, we examined the genotypes of EVs detected in endomyocardial biopsies and pericardial effusions by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP) analysis. Positive PCR results were obtained from biopsies in 6 (19 percent) of 31 patients with DCM, 5 (18 percent) of 28 with myocarditis, 5 (22 percent) of 23 with other cardiac diseases, and from pericardial effusions in 4 (57 percent) of 7 patients with pericarditis. SSCP profiles of most of the clinical samples were different and were not identical to any of the standard group B coxsackie viruses. Our findings suggest that EV genomes are involved in the myocardium of patients with various cardiac conditions and that a particular type of EV is not present in DCM hearts.

[Management of total laboratory system and its efficacy]

The Osaka City University Hospital was reopened in May 1993. In the Central Clinical Laboratory our Total Laboratory Automation System, a comprehensive online analyzing system, covers the entire process from collecting blood to completing tests. Our study showed that an average of 2,800 outpatients were examined per day in 1994, compared with 1,900 per day in 1992, an increase of 47.4%. The number of tests performed by the central laboratory in 1994 was 5,610,000 as compared to 3,720,000 in 1992, an increase of 50.8%. After the installation of the transport line and computerization the following can be noted: 1) We were able to extend reception hours by two hours. 2) We are now able to assign lab medical technologists to physiology analysis, emergency analysis, and initial outpatient testing. We conclude that these effects have been very large.

Analysis of enterovirus genotypes using single-strand conformation polymorphisms of polymerase chain reaction products

Enterovirus genotypes were identified rapidly by reverse (RT-PCR) followed by single-strand conformation polymorphism (SSCP) analysis. The primer pair was chosen from the highly conserved sequence at the 5' non-coding region of enterovirus genomes. RT-PCR amplified a 154 bp sequence in all samples from 14 serotypes of enteroviruses, including group A and B Coxsackie viruses, echoviruses and polioviruses. SSCP analysis of these products revealed different electrophoretic profiles. Thus, SSCP analysis will be useful for differentiating the genotypes of enteroviruses, and may be applicable for rapid diagnosis of enteroviral infection.