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Biomedical subjects

G M Boffa

Publications and source records attributed to G M Boffa.

At least 37 records · Page 2Linked to original sources
PubMed1993

Endomyocardial biopsy in right ventricular cardiomyopathy.

Right ventricular cardiomyopathy is characterized by a progressive myocyte loss and fibro-fatty substitution of the right ventricle. The aim of our study was to assess the diagnostic accuracy of right ventricular endomyocardial biopsy. Using an imaging analyser system, histomorphometric parameters of myocytes, interstitium, fibrous tissue and fatty tissue were evaluated on endomyocardial biopsy from 30 patients with arrhythmogenic right ventricular cardiomyopathy, 29 patients with dilated cardiomyopathy and 30 control patients. The percent area of myocytes decreased from 78.10 +/- 7.34 in control to 63.39 +/- 9.22 in dilated cardiomyopathy (P < 0.05) and to 47.28 +/- 15.01 in arrhythmogenic right ventricular cardiomyopathy (P < 0.01). Fibrous tissue increased from 8.10 +/- 3.89 in control to 21.80 +/- 9.29 in dilated cardiomyopathy (P < 0.05) and to 24.60 +/- 11.37 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fatty tissue varied from 0.33 +/- 1.44 in control and 0.07 +/- 0.31 in dilated cardiomyopathy to 13.30 +/- 17.30 in arrhythmogenic right ventricular cardiomyopathy (P < 0.05). Fatty tissue was a feature of arrhythmogenic right ventricular cardiomyopathy (67% of patients vs. 6% of control and dilated cardiomyopathy patients). Diagnostic values typifying arrhythmogenic right ventricular cardiomyopathy, obtained by excluding any overlapping between confidence intervals in the three groups, were: myocytes < 44.95%; fibrous tissue > 40.38%, and fatty tissue > 3.21%, with 67% sensitivity and 91.53% specificity for at least one parameter. In conclusion, a significant difference between arrhythmogenic right ventricular cardiomyopathy, dilated cardiomyopathy and control exists in terms of amount of myocytes, fibrous tissue and fatty tissue. Presence of fatty tissue and fibrous tissue exceeding 3.21% and 40.38%, respectively should be considered highly suspect for arrhythmogenic right ventricular cardiomyopathy in right ventricular endomyocardial biopsy.

Adipose Tissue↗
PubMed1993

Endomyocardial biopsy in heterotopic heart transplant recipients via the femoral vein.

The results of endomyocardial biopsy (EMB) via the femoral vein in heterotopic heart transplant recipients were retrospectively analyzed and compared with those obtained using the right internal jugular vein approach. A total of 139 EMB were performed in 8 patients using the femoral (35) or the jugular (104) approach. Twenty three (64.7%) of the procedures performed via the femoral vein were part of the yearly hemodynamic and coronary artery study, and 12 (35.3%) constituted a routine postoperative evaluation of the myocardium rejection state in patients with imperviousness of the right internal jugular vein. Comparing the results obtained with the femoral approach, we observed a higher overall success rate (94.3 vs 88.5%, NS) and obtained more samples that were useful for histologic evaluation (95.5 vs 85.9%, NS); with the jugular procedure, the fragments were significatively larger in diameter (1.28 +/- 0.55 vs 1.61 +/- 0.85 mm, mean +/- SD) and in area (1.49 +/- 1.16 vs 2.28 +/- 2.24 mm2, mean +/- SD). No cardiac or local complications were noted when the femoral approach was used, while two attempts to perform biopsy via the jugular vein resulted in obstruction of this vessel. Our data suggest that the femoral venous approach for endomyocardial biopsy in heterotopic heart transplant recipients is a valid alternative to the more commonly used routes.

Biopsy↗
PubMed1993

Clinical results of steroid-free induction immunosuppression after heart transplantation.

Between January 1987 and September 1991, 112 operative survivors of heart transplantation were initially immunosuppressed with cyclosporin A and azathioprine without prednisone. Eighty-eight patients (79%) remained on a regimen of double therapy for a mean follow-up of 25 +/- 15 months (range, 1 to 54 months), whereas 24 patients (21%) had oral prednisone, 5 mg/day, added to maintenance therapy for persistent or repeated rejection. There were 5 early deaths (4%) because of acute rejection (4 patients) or infection (1 patient). Only 1 patient died late after heart transplantation of chronic rejection. Actuarial survival was 95% +/- 2% and 94% +/- 3% at 12 and 48 months, respectively. Mean rate of acute rejection was 1.7 +/- 1.0 episodes per patient, with a 5% +/- 2% freedom from rejection at 48 months. Ten patients (9%) required in-hospital treatment for infection; the actuarial freedom from infectious episodes was 85% +/- 4% at 48 months. Actuarial freedom from hypertension was 43% +/- 7% at 48 months. At annual catheterization, mean left ventricular ejection fraction was 0.64 +/- 0.08 and 0.62 +/- 0.05 at 1 year and 4 years, respectively, with evidence of coronary lesions in 9 patients (8%). In conclusion, steroid-free immunosuppression after heart transplantation is associated with a high incidence of acute rejection. However, the excellent medium-term survival and the low incidence of both infection and chronic rejection seem to justify a wider use of such treatment.

Adolescent↗
PubMed1993

Hypertrophic cardiomyopathy with mitochondrial myopathy. A new phenotype of complex II defect.

Two brothers, 25 and 19 years old, were affected by asymmetrical hypertrophic cardiomyopathy. The older brother had waddling gait and weakness of the proximal girdle muscles, while the younger had a broad-based gait and weakness of selected limb girdle muscles. EMG exam was myopathic. Serum enzyme, CPK and aldolase were elevated. Histochemical reactions in muscle revealed "core-like" areas, subsarcolemmal rims of mitochondria and lipid accumulation. Succinate-dehydrogenase stain showed a lack of activity in both biopsies, with the exception of intrafusal fibers. Microphotometric quantitative measurements confirmed the defect in both biopsies. Biochemical measurements of several mitochondrial enzymes in muscle showed a reduced activity of succinate-dehydrogenase (33%) and succinate-cytochrome C reductase (36-47%) which are both components of complex II. On myocardial biopsy lipid and mitochondrial abnormalities were found. This mitochondriopathy represents a new phenotype of partial complex II defect.

Adult↗
PubMed1993

[Morphofunctional correlations in dilated cardiomyopathies].

The aim of this study was to state whether in patients with dilated cardiomyopathy indices of left ventricular function (i.e. left ventricular end-diastolic and end-systolic volumes, ejection fraction, end-systolic pressure to end-systolic volume ratio, mass to volume ratio, elastic stiffness constant) are related to histologic findings, namely percentage of myocytes, of fibrosis and of interstitium. We have studied 26 patients (18 males and 8 females) aged 13-65 years, who underwent right and left heart catheterization, quantitative angiography, coronary angiogram, and in whom a diagnosis of dilated cardiomyopathy was established. All of them had a biopsy specimen taken from the right aspect of interventricular septum, following the technique of King's College. Histology was automatically evaluated with a computerized system for the percent content of myocytes, of fibrous tissue and interstitium. Correlation with hemodynamic parameters was calculated with the least square method. A significant correlation was found between percentage of fibrosis, left and right ventricular ejection fraction and preload index, and between percent myocytes and right ventricular ejection fraction and duration of disease. Thus, left ventricular function indices do not correlate with percent myocytes, as previously shown: this could be due to the fact that alterations in contractile machinery are due primarily to alterations in cell biochemistry. Moreover, the inverse relationship between myocyte content and duration of the disease may reflect those mechanisms, which tend to perpetuate failure in a dilated heart by increasing subendocardial fibrosis. However, the correlation found between myocyte content and right ventricular ejection fraction may be due to the fact that biopsy specimens were taken from the right ventricle.

Adolescent↗
PubMed1992

[Persistent T-wave inversion in unstable angina: the correlation with the global and regional function of the left ventricle].

The correlation between persistent negative T wave on basal electrocardiogram and coronary anatomy or global and regional left ventricular function was investigated in 34 patients with unstable angina defined as new onset (< 2 months), crescendo or rest angina. The patients with history of previous myocardial infarction, pathological Q waves on electrocardiogram or documented elevation of CPK were excluded. Eighteen patients (group A) showed T wave inversion (> 1 mV) in at least two leads on the basal electrocardiogram, persisting for at least 48 hours before coronary arteriography. In 16 patients (group B) the basal electrocardiogram was normal. Left ventricular volumes and ejection fraction were calculated and the regional systolic wall motion was analyzed using the area method in the 30 degrees right anterior oblique view. Hypokinesis was defined as more than 2 standard deviation below the mean value calculated in 24 normal subjects. No difference was present for age (A: 61 +/- 9 vs B: 57 +/- 9 yrs) and sex distribution. Critical stenoses of at least one coronary artery was documented in all but one patient (in group B). The number of critical stenosis per patient was equal (1.8) in the two groups. Left main coronary artery showed narrowing > 50% in three patients of group A and in two patients of group B.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

The effect of propionyl-L-carnitine on the ischemic and reperfused intact myocardium and on their derived mitochondria.

To assess whether propionyl-L-carnitine protects rabbit heart against the deterioration caused by ischemia and reperfusion, isolated hearts were infused with a medium containing it in different concentrations. During control, normoxic perfusion, and 60 minutes of low-flow ischemia (37 degrees C) followed by 30 minutes of reperfusion, diastolic, and developed pressures were monitored; coronary effluent was collected and assayed for lactate and creatine phosphokinase (CPK); mitochondria were harvested and assayed for oxidative phosphorylation and calcium content; and tissues for concentration of adenosine triphosphate (ATP) and creatine phosphate. Propionyl-L-carnitine reduced the ischemic deterioration of mitochondrial function and the depletion of tissue stores of ATP. On reperfusion, hearts treated with it recovered better than the untreated hearts with respect to left ventricular performance, replenishment of ATP and CP stores, and mitochondrial function. The reperfusion-induced mitochondrial calcium overload and release of CPK were also reduced. The effect of propionyl-L-carnitine was dose dependent. At 10(-8) M it failed to modify ischemic and reperfusion damage but protected well at 10(-7) M. No further protection was obtained at 10(-6) M. Propionyl-L-carnitine thus protects the myocardium against some of the deleterious effects of ischemia and reperfusion. In particular it protects mitochondrial function, perhaps partly by preventing mitochondrial calcium overload. Because this protection occurs in the absence of a negative inotropic effect during normoxia or of a coronary dilatatory effect during ischemia, it cannot be attributed to an energy-sparing effect or to the improvement of oxygen delivery.

Adenosine Triphosphate↗
PubMed1991

Cardiomyopathy: a necessary revision of the WHO classification.

The classification of myocardial disease proposed by the WHO/ISFC task force in 1980 distinguishes specific heart muscle diseases from myocardial diseases of unknown origin, termed cardiomyopathies, and differentiated into the dilated, hypertrophic and restrictive forms. This last group includes endomyocardiofibrosis and fibroblastic parietal endocarditis. In more recent years, two new forms of heart muscle disease have been recognized: so-called "primary" restrictive cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy. Primary restrictive cardiomyopathy is characterized anatomically by normally sized, non-hypertrophic ventricles with dilated atria, and functionally by impaired diastolic compliance due to myocardial stiffness. The clinical picture is that of chronic congestive heart failure; histology shows interstitial fibrosis and myocardial disarray, but not hypereosinophilia. In arrhythmogenic right ventricular cardiomyopathy, the myocardium of the right ventricular free wall is substituted by fibrous and/or adipose tissue, which results in regional dynamic alterations and ominous ventricular arrhythmias. The left ventricle is usually spared. Both forms should be classified as heart muscle diseases of unknown origin, and kept clearly distinct from the other cardiomyopathies listed in the WHO classification.

Arrhythmias, Cardiac↗
PubMed1991

Haemodynamic effects of nisoldipine by oral route.

The aim of this study is to investigate the acute haemodynamic effect of orally administered nisoldipine. Eight patients with stable angina and normal overall ventricular function were submitted to cardiac catheterization and angiography before and one hour after administration of nisoldipine 20 mg per os. Cardiac output increased, peripheral resistance decreased and aortic compliance increased, determining a marked decrease in overall peripheral impedance. Left ventricular ejection fraction hardly increased and contractility did not vary. Left ventricular end diastolic pressure decreased, owing to a decrease in left ventricular wall stiffness. Thus nisoldipine acts as a peripheral dilating agent, decreasing arteriolar tone and, possible, venous tone, and increasing left ventricular muscle distensibility.

Administration, Oral↗
PubMed1990

The concept of preload and its evaluation in the intact left ventricle.

Preload affects left ventricular pump function through the Frank-Starling curve by changing sarcomere length. However, common indices of preload, such as end-diastolic volume, or pressure, or stress, do not necessarily reflect sarcomere length. Ultimately, this depends on the elastic stiffness constant (k) and end-diastolic stress (sigma), which are not in simple relation with the above mentioned indices. An index of preload is proposed, (k sigma)(1/k). This index has been evaluated in 148 patients with different degrees of hemodynamic overload, and in 24 normal subjects. The preload index was found to be 1.448 +/- 0.034 in normal subjects. However, in the other patients evaluated preload index increased in mitral insufficiency (1.490 +/- 0.035), in decompensated aortic insufficiency (1.490 +/- 0.89) and in dilated cardiomyopathy (1.52 +/- 0.125), and markedly decreased in aortic stenosis (1.367 +/- 0.039) and in hypertrophic cardiomyopathy (1.41 +/- 0.034). It was always positively related to the afterload, measured as peak systolic stress. No positive relationship was found with end-diastolic volume nor pressure. Therefore, preload as a compensatory mechanism is differently recruited in response to various degrees of hemodynamic overload and parallels the afterload, in agreement with the concept of preload-afterload mismatch.

Aortic Valve Insufficiency↗
PubMed1990

Antioxidant protection against damage during cardiac ischemia and reperfusion: effect of dimercapto-propanol.

Oxygen-derived free radicals and their metabolites may contribute to the extension of cellular injury that occurs on reperfusion of the ischemic myocardium; and therapy directed against the toxic effects of reactive oxygen species has provided protection to the ischemic myocardium which undergoes subsequent reperfusion. We evaluated the effectiveness of dimercapto-propanol (1,2-dimercapto-propanol, British Anti-Lewisite, dimercaprol) to limit the extent of myocardial damage resulting from 60 minutes of severe ischemia followed by 30 minutes of reperfusion in the Langendorff-perfused rabbit heart. Dimercaptopropanol is a thiol agent, with two free sulfhydryl groups per molecule, which has no effect on glutathione status nor on the total tissue thiol pool. Pretreatment of the hearts with 10(-6) M dimercapto-propanol resulted in marked myocardial protection, measured in terms of preserved mechanical function and reduced creatine kinase release. On reperfusion less oxidative stress developed. The beneficial effects of dimercapto-propanol could not be explained by hemodynamic differences or effects on energy metabolism. In addition, it is unlikely that dimercapto-propanol acts as a free radical scavenger at the concentrations employed. The protection may be achieved by the drug keeping some key sulfhydryl groups of functional proteins in the reduced state.

Animals↗
PubMed1989

Effects of iloprost (ZK 36374) on glutathione status during ischaemia and reperfusion of rabbit isolated hearts.

1. Reperfusion of rabbit isolated hearts after 60 min of ischaemia resulted in poor recovery of mechanical function, release of creatine phosphokinase (CPK) and of reduced (GSH) and oxidized (GSSG) glutathione, reduction of mitochondrial superoxide dismutase (Mn SOD) activity and of tissue GSH/GSSG ratio with a shift of cellular thiol redox state toward oxidation, suggesting the occurrence of oxidative stress. 2. Pretreatment of the isolated heart with the stable prostacyclin analogue (iloprost) at 27 or 270 nM, but not at 2.7 nM, improved the functional recovery of the myocardium, reduced CPK, GSH and GSSG release, maintained Mn SOD activity and attenuated the occurrence of oxidative stress. 3. This effect of iloprost cannot be explained by a decreased demand or an enhanced delivery of oxygen during ischaemia or by a direct effect on glutathione peroxidase and reductase activity.

Animals↗
PubMed1989

Oxygen free radical-mediated heart injury in animal models and during bypass surgery in humans. Effects of alpha-tocopherol.

There is evidence that oxygen free radicals play a role in myocardial ischemic and reperfusion injury. We investigated the effect of ischemia and reperfusion on glutathione status. Reperfusion after prolonged ischemia (60 min) induced an important release of reduced (GSH) and oxidized (GSSG) glutathione, concomitant with an increase of tissue GSSG and no recovery of mechanical function, indicating that reperfusion results in oxidative stress. These alterations are associated with tissue and mitochondrial calcium accumulation, loss of mitochondrial function, and membrane damage. We also determined the arteriocoronary sinus difference for GSH and GSSG of 16 CAD patients undergoing coronary artery bypass. Patients were divided in two groups according to the length of clamping period: 25 +/- 2 min (group 1), and 55 +/- 6 min (group 2). In group 1, reperfusion resulted in a transient release of GSH, GSSG, CPK, and lactate, with return to preclamping values in 10 minutes. In group 2, reperfusion determined a sustained and pronounced release of GSH, GSSG, CPK, and lactate during declamping, suggesting the occurrence of an oxidative stress. Using an in vitro model, administration of alpha-tocopherol bound with albumin showed protection of mitochondrial function, improved recovery of contraction, and reduced oxidative stress during reperfusion.

Animals↗
PubMed1989

[Natural history of dilated cardiomyopathy].

Seventy-seven patients with dilated cardiomyopathy (50 M and 27 F, aged 38 +/- 16 yrs) were followed up until Dec 31, 1985. Haemodynamic investigation was performed in all cases, and all pressure and left ventricular quantitative angiography parameters were collected. In no case did the coronary angiogram show significant lesions. Mean values of haemodynamic parameters for surviving and deceased patients were compared. Forty-six patients survived and 28 died during the follow-up period. Although all patients had an enlarged left ventricle and depressed contractility, survivors had either greater pressure/end systolic volume ratio or a greater stress/end systolic volume ratio. Survival curves confirm a particularly severe prognosis for patients with Suga index less than 1 or stress to end systolic volume ratio less than 2.5. Mass to volume ratio seems to affect two-year but not late survival. NYHA class does not indicate early survival. In conclusion, left ventricular function is obviously related to prognosis in these patients, but it seems still difficult to assess life expectancy from these parameters alone.

Adult↗
PubMed1988

Accelerated idioventricular rhythm of infundibular origin in patients with a concealed form of arrhythmogenic right ventricular dysplasia.

Five apparently healthy people (aged 16-47) presented with recurrent episodes of accelerated idioventricular rhythm characterised by left bundle branch block and right axis deviation. Clinical history, physical findings, basic electrocardiogram, chest x ray, and blood tests were within normal limits in all. Holter monitoring, exercise stress test, and electrophysiological study (in three patients) showed that accelerated idioventricular rhythm was mainly bradycardia dependent, easily suppressed by effort and overdrive pacing, and originated from the outflow tract of the right ventricle. The mechanism could be enhanced automaticity. Data from cross sectional echocardiography (in all patients) and from haemodynamic evaluation (in three) identified structural or wall motion abnormalities of the right ventricle or both without appreciable dilatation of the ventricle. Biopsy specimens of the right ventricular endomyocardium showed fibrosis in one patient, fibrosis and fatty infiltration in the second, and pronounced fatty infiltration in the third. These results show that some patients with accelerated idioventricular rhythm have right ventricular abnormalities that are typical of the localised and concealed forms of arrhythmogenic right ventricular dysplasia.

Adolescent↗