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V Regitz

Publications and source records attributed to V Regitz.

At least 19 recordsLinked to original sources

Myocardial adenine nucleotide concentrations and myocardial norepinephrine content in patients with heart failure secondary to idiopathic dilated or ischemic cardiomyopathy.

It has been suggested that chronically reduced myocardial adenosine triphosphate (ATP) content causes contractile dysfunction in dilated cardiomyopathy. Because total adenine nucleotides (ATP, adenosine diphosphate and monophosphate) may reflect chronic changes in energy metabolism better than may ATP alone, myocardial ATP, and adenosine diphosphate and monophosphate were determined in endomyocardial biopsy specimens from 19 patients with dilated cardiomyopathy, and decreased left (30 +/- 2%) and right (34 +/- 3%) ventricular ejection fractions, and from 11 patients with ischemic cardiomyopathy (left ventricular ejection fraction 38 +/- 3%), and compared with those from 28 normal control subjects (ejection fraction greater than 55%) to assess myocardial energy metabolism in heart failure. Myocardial norepinephrine was measured simultaneously in the same biopsy specimens to assess if the myocardium studied for adenine nucleotide content was metabolically altered. Myocardial total adenine nucleotides as well as ATP levels in 19 patients with dilated cardiomyopathy (39 +/- 3 and 23 +/- 3 nmol/mg of noncollagen protein, respectively) were unchanged in comparison with those of control subjects (37 +/- 4 and 23 +/- 3, respectively); patients with ischemic cardiomyopathy were not significantly different (30 +/- 3 and 19 +/- 3, respectively). Myocardial norepinephrine in the same biopsy specimens from patients with dilated (5.8 +/- 1.1 pg/micrograms of noncollagen protein) or ischemic (5.7 +/- 1.3) cardiomyopathy was significantly decreased compared with that of normal control subjects (12 +/- 1.1).(ABSTRACT TRUNCATED AT 250 WORDS)

Adenine Nucleotides

Level and diurnal variations of hormones of interest to the cardiovascular system in patients with heart transplants.

The lack of a nocturnal decrease in blood pressure in cyclosporine-treated cardiac transplant recipients may indicate abnormalities in the mechanism(s) responsible for circadian variability in other physiologic parameters such as in circulating hormones. This possibility was addressed through repeated determinations of circulating catecholamines, neuropeptide Y, pancreatic polypeptide, calcitonin gene-related peptide, plasma renin activity, aldosterone, atrial natriuretic factor and cortisol. The results from 10 patients with heart transplants were compared with those of 12 age-matched, healthy control subjects. Both groups were studied during 24-hour supine rest. There was no difference between patients and control subjects in mean levels of catecholamines, neuropeptide Y, pancreatic polypeptide and aldosterone. Patients had higher levels (+/- SD) of plasma renin activity (6.4 +/- 1.3 vs 2.6 +/- 0.4 ng/ml/hour, p less than 0.001), calcitonin gene-related peptide (47.7 +/- 9.9 vs 33.3 +/- 5.7 pmol/liter, p less than 0.01) and atrial natriuretic factor (93.0 +/- 56.7 vs 20.7 +/- 8.9 pg/ml, p less than 0.001) than control subjects, respectively. Cortisol was not detected in patients. Abnormal diurnal profiles in patients were found for calcitonin gene-related peptide, aldosterone and atrial natriuretic factor, and for pancreatic polypeptide, together with decreased levels, in patients with greater than 6 months follow-up. Except for hormones reflecting sympathetic nervous activity, all hormonal systems studied showed abnormalities in level or circadian rhythmicity, or both. The pancreatic polypeptide results suggest that parasympathetic neuropathy could develop in cyclosporine-treated heart transplant recipients.

Adrenal Cortex Hormones

Adenine nucleotide metabolism and contractile dysfunction in heart failure--biochemical aspects, animal experiments, and human studies.

In myocardial hypertrophy and heart failure a series of adaptational changes occur some multiplying contractile units, others slowing shortening velocity and increasing economy of contraction. The demonstration of energy-saving mechanisms in heart failure has prompted further investigations of energy providing and utilizing metabolic pathways. The use of myocardial ATP as a substrate occurs mainly at the myosin-ATPase and at the Ca-ATPase of the sarcoplasmic reticulum. As the Michaelis constant of both enzymes for ATP is in the micromolar (microM) range, whereas cellular ATP content is about 5000 microM, these enzymes are not controlled by the availability of ATP as a substrate. In experimental heart failure in large animals, normal or reduced creatine phosphate levels (in most cases together with normal adenine nucleotides) have been described. Reduced creatine phosphate is found in models with increased oxygen consumption, and creatine phosphate may buffer the ATP pool in these models. In human heart failure due to dilated cardiomyopathy, where resting oxygen consumption per unit mass and lactate extraction are normal in most patients, normal adenine nucleotides, creatine phosphate, and mitochondrial function have been described in the initial studies. These results have been challenged by one study showing decreased ATP levels in dilated cardiomyopathy, correlating with the decrease in ejection fraction. However, only ATP has been measured in this study, whereas total adenine nucleotides may be a more suitable parameter. Recently published results have again demonstrated normal ATP and total adenine nucleotides in human heart failure. In the same patients, significantly decreased myocardial norepinephrine was measured, indicating that metabolic changes had occurred in these hearts, but were independent of adenine nucleotides.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological

Myocardial L-carnitine deficiency in a family of dogs with dilated cardiomyopathy.

Dilated cardiomyopathy in a family of dogs was found to be associated with decreased myocardial L-carnitine concentrations, when compared with those in control dogs. In 2 affected dogs, treatment with high doses of L-carnitine was associated with increased myocardial L-carnitine concentration and greatly improved health and myocardial function. Withdrawal of L-carnitine supplementation from these dogs resulted in development of myocardial dysfunction and clinical signs of dilated cardiomyopathy.

Animals

Protective effects of propionyl-L-carnitine during ischemia and reperfusion.

When cardiac function in isolated rat hearts was impaired by subjecting them to ischemia, subsequent perfusion with propionyl-L-carnitine and related compounds increased their rate of recovery. Thus at 11 mM, both propionyl-L-carnitine and, to a lesser extent, its taurine amide, and also acetyl-L-carnitine, significantly restored cardiac function in 15 minutes after 90 minutes of either low-flow or intermittent no-flow ischemia. Carnitine itself was ineffective. Propionyl-L-carnitine also increased tissue ATP and creatine phosphate compared with controls, but did not affect the levels of long-chain acyl carnitine and coenzyme. These esters also depleted fatty acid peroxidation, as shown with malonaldehyde, and were more effective than carnitine in preventing the production of superoxide. In myocytes, propionyl-L-carnitine alone stimulated palmitate oxidation, but in rat heart homogenates, both L-carnitine and propionyl-L-carnitine did so, while acetyl-L-carnitine was actually inhibitory. Possible mechanisms for the protective action of propionyl-L-carnitine against ischemia include an increased rate of cellular transport, stimulation of fatty acid oxidation, and a reduction of free radical formation.

Acetylcarnitine

Myocardial catecholamine concentrations in dilated cardiomyopathy and heart failure of different origins.

Myocardial catecholamine concentrations were determined in endomyocardial biopsies from patients with heart failure to assess if tissue catecholamine levels relate to the severity of myocardial damage or the aetiology of the underlying disease. Methodological studies revealed a good reproducibility of catecholamine determinations in biopsies; the variance between paired biopsies was below 17% when myocardial catecholamines were related to non-collagen protein (NCP). Myocardial norepinephrine (in pg micrograms-1 NCP) levels were comparable in patients with dilated cardiomyopathy (DCM, 5.3 +/- 3.4, n = 22) and in patients with coronary or valvular heart disease (5.6 +/- 4.7, n = 14). In both groups, a significant reduction of myocardial norepinephrine was found (controls 12.0 +/- 3.4, P less than 0.0006). In a subgroup of patients with heart failure and a LVEF less than 30% (3.9 +/- 3.5, n = 17) myocardial norepinephrine content was lower than in patients with heart failure and LVEF of 31-55% (6.6 +/- 3.4, n = 19) (both P less than 0.05 against controls: 12.0 +/- 3.4, n = 16). A correlation between myocardial norepinephrine and LVEF was found in DCM (P less than 0.001, r = 0.70). The loss of myocardial norepinephrine is a characteristic feature of heart failure. It is independent of the origin of failure, but correlates with the impairment of LV function.

Cardiomyopathy, Dilated

[Coronary fistulas--high prevalence in patients with heart transplantation].

Coronary artery fistulas have recently been reported to occur frequently in patients after heart transplantation due to repeated endomyocardial biopsies. To investigate if there is a relationship between development of coronary artery fistulas and the number of biopsies performed in transplanted patients, we studied the prevalence and localization of coronary artery fistulas in 168 patients after heart transplantation and in 100 control subjects. In addition to biplane ventriculography of the left ventricle, and in two-thirds of the patients the right ventricle as well, coronary angiography in multiple projections was performed at yearly intervals. The angiographic criterion for a coronary fistula was specified as visualization of a direct confluence from the arterial vascular lumen into a cardiac chamber, independent of size, which occurred prior to the venous phase, documented by opacification of the coronary sinus or great cardiac vein. The size of the fistula was assessed semi-quantitatively into one of three categories as small, barely detectable flow from a small arterial vessel with opacification of less than 10% of the involved chamber, large with direct flow from a large branch with opacification of more than one-third of the involved chamber (Figures 1a to 1c). Endomyocardial biopsies were performed weekly for the first three months after transplantation, thereafter, the interval was increased one week every three months. The prevalence of coronary fistulas in patients after heart transplantation was higher at 135/168 than in control subjects at 43/100. There were also more fistulas per patient (1.8 vs 0.67) in those transplanted than in control subjects (Figures 2a and 2b).(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriovenous Fistula

Defective myocardial carnitine metabolism in congestive heart failure secondary to dilated cardiomyopathy and to coronary, hypertensive and valvular heart diseases.

Reduced myocardial carnitine concentrations in the explanted heart and elevated plasma levels have been found in patients undergoing heart transplant for end-stage congestive heart failure (CHF). To evaluate a possible loss of myocardial carnitine in less severe stages of CHF, total myocardial carnitine levels were compared in right ventricular endomyocardial biopsies from 28 patients with mild, moderate and severe dilated cardiomyopathy, 8 patients with CHF of different origin and 13 normal control subjects. If possible, free myocardial carnitine and free and total plasma carnitine were also determined. For the first time, myocardial carnitine levels have been measured in endomyocardial biopsies from 13 normal human hearts (control values: 9.9 +/- 0.8 nmol/mg noncollagen protein). In comparison with these control values, total myocardial carnitine was significantly reduced in patients with dilated cardiomyopathy (6.1 +/- 0.5 nmol/mg noncollagen protein, p less than 0.0001), and CHF of other origins (6.6 +/- 1.1 nmol/mg noncollagen protein, p less than 0.02). Free myocardial carnitine concentrations in dilated cardiomyopathy (4.6 +/- 0.4 nmol/mg noncollagen protein) and CHF of different origin (4.4 +/- 0.5 nmol/mg noncollagen protein) were also significantly different from control values (control values: 9.7 +/- 0.7 nmol/mg noncollagen protein, p less than 0.0001 and p less than 0.005 for both groups). The loss of free and total myocardial carnitine was comparable in dilated cardiomyopathy and CHF due to other diseases. In contrast, plasma free and total carnitine levels in the CHF patients were significantly elevated (67 +/- 5.5 mumol/liter, control values 41 +/- 3.7 mumol/liter, p less than 0.005). Alterations in myocardial carnitine metabolism represent nonspecific biochemical markers in CHF with yet unknown consequences for myocardial function.

Adult

Myocardial catecholamine content after heart transplantation.

Myocardial catecholamine levels have not yet been determined in the transplanted human heart. We measured norepinephrine, epinephrine, and dopamine in endomyocardial biopsies from 19 short-term (organ age, 6.6 +/- 6 months) and five long-term (organ age, 62 +/- 2 months) heart transplant patients. Results were compared with those from 10 normal control subjects. In 17 of 19 short-term heart transplant patients, myocardial catecholamines were undetectable, indicating values below 0.1 pg/micrograms noncollagen protein, which was the detection threshold of our assay. In the remaining two patients, myocardial catecholamines (pg/microgram noncollagen protein) were norepinephrine (1.4 and 3.2), epinephrine (0.8 and 1.9), and dopamine (0.9 and 2.3), respectively. In the five long-term heart transplant patients, myocardial catecholamines were not detected. Catecholamine concentrations in 10 healthy control subjects were norepinephrine (10.3 +/- 2.9), epinephrine (0.36 +/- 0.51), and dopamine (0.52 +/- 0.40). Low myocardial norepinephrine levels (less than 20% of control values) with unexplained high levels of epinephrine and dopamine were found in single transplant patients. In most heart transplant patients, however, myocardial catecholamines were undetectable up to five years after transplantation, indicating that the adrenergic response of these hearts probably depends on variations in plasma catecholamines or cardiac beta-receptor density.

Biopsy

Metabolic alterations in end-stage and less severe heart failure--myocardial carnitine decrease.

Severe tissue carnitine deficiency impairs fatty acid oxidation. In explanted hearts from patients with end stage heart failure a 57% carnitine decrease was found in comparison with healthy donor hearts (p less than 0.05). The reduction of myocardial carnitine levels affected all areas of the explanted hearts to a comparable extent. Carnitine decreases in patients with dilated cardiomyopathy or coronary artery disease were similar. Endomyocardial biopsies from patients with less severe heart failure due to cardiomyopathy (n = 28) or other myocardial diseases (n = 8) showed a 42% decrease of total myocardial carnitine (in nmol/mg non-collagen protein) in comparison with biopsies from patients with normal cardiac function (controls) (heart failure: 5.7, confidence interval 4.2-7.0; controls 9.3, confidence interval 7.6-12.0, p less than 0.005). Free myocardial carnitine in heart failure was also different from controls (heart failure: 4.2, confidence interval 3.7-5.3; controls 10.3, confidence interval 7.5-12.2, p less than 0.001). The decrease of free and total myocardial carnitine was comparable in dilated cardiomyopathy and heart failure due to other diseases. Alterations in myocardial carnitine content represent therefore non-specific biochemical markers in heart failure with yet unknown consequences for myocardial function.

Adult

Modified transvenous endomyocardial biopsy technique in dogs.

A technique for transvenous endomyocardial biopsy of the right ventricle was developed and evaluated for safety and efficacy in healthy dogs and dogs with dilated cardiomyopathy positioned in lateral recumbency. This technique allowed acquisition of multiple biopsy specimens from the right ventricle of each of 22 hemodynamically normal dogs and 40 of 42 dogs with congestive heart failure. In 2 dogs with dilated cardiomyopathy, transvenous access to the right ventricle could not be achieved, but left ventricular biopsy was performed without complication. Complications were infrequent, and dogs recovered to at least their baseline status within 48 hours. Evaluation of the efficacy and complication rate of the procedure with each of the 2 biopsy instruments currently available identified no differences between them.

Animals

[Myocardial catecholamine content in heart failure--I: Regional distribution in explanted hearts. Comparison between dilated cardiomyopathy and coronary heart disease].

To quantify the myocardial catecholamine content in heart failure patients and to assess the regional distribution of catecholamines, we investigated norepinephrine and dopamine concentrations in explanted hearts from 34 patients in end-stage heart failure. 28 patients with cardiomyopathy were compared with six patients with coronary artery disease. In comparison with the right atria of a control group without heart failure, reduced myocardial norepinephrine contents (in pg/micrograms non-collagen protein (NCP] were found in all areas of the explanted hearts: controls: right atrium 17.6 +/- 6.6; cardiomyopathy: right atrium 7.1 +/- 7.9, right ventricle 4.4 +/- 2.7, septum 3.8 +/- 1.5, left ventricle 3.5 +/- 1.4. Coronary artery disease: right atrium 7.0 +/- 6.9, right ventricle 4.2 +/- 2.6, septum 3.6 +/- 1.4, left ventricle 3.4 +/- 1.4. Highest norepinephrine levels were measured in the right atrium. Right ventricle, septum, base and midventricular portion of the left ventricle had lower concentrations and were not different from each other. In contrast to reduced norepinephrine (NE) levels in all patients, dopamine (Dop) was inhomogenously elevated (only in a subgroup of 44%). Catecholamine contents in any two arbitrarily selected areas correlated significantly (NA: r = 0.53-0.77; Dop: r = 0.81-0.93, p less than 0.05 in all cases). The patients with heart failure due to dilated cardiomyopathy and to coronary artery disease did not differ in myocardial catecholamine levels or distribution. In end-stage heart failure a significant loss of myocardial norepinephrine independent from the underlying disease is found. It affects all areas of the hearts but does not equalize catecholamine content in ventricles and atria.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult

[Myocardial catecholamine content in heart failure--II: Measurement in endomyocardial biopsies, reference systems, normal values].

To enable the assessment of a possible gradual loss of myocardial catecholamines in heart failure, we determined control values in endomyocardial biopsies from normal human right ventricular myocardium. The reproducibility of the determinations and its dependence on the reference system, wet weight (wwt) or non-collagen-protein (NCP), was investigated in explanted hearts. Parallel determinations of norepinephrine in several samples from 1-2 mg in the same heart yielded a variability of about 20%. To obtain reproducible values, catecholamine concentrations had to be related to non-collagen-protein. Non-collagen-protein content was higher in the ventricles (138 +/- 16 micrograms/mg wwt) than in the atria (102 +/- 15 micrograms/mg wwt). Norepinephrine levels in normal human myocardium, measured in right ventricular endomyocardial biopsies were 10.3 +/- 3 pg/micrograms NCP. If they were compared with norepinephrine levels in right atrial samples from 11 patients without heart failure, obtained at open heart surgery (17.6 +/- 6 pg/micrograms NCP), an atrioventricular gradient, with ventricular norepinephrine content being 58% of right atrial levels was calculated for healthy human hearts. This gradient was almost identical with that found in heart failure, patients, where right ventricular norepinephrine amounted to 60% of right atrial levels. This implicates a percentually homogeneous loss of norepinephrine in heart failure, which, however, does not equalize ventricular and atrial levels. Thus, to interpret myocardial catecholamine content in cardiac diseases, normal values in corresponding areas are mandatory.

Adult

Restenosis after balloon dilatation of coronary stenosis, multivariate analysis of potential risk factors.

This study was undertaken to analyze change in stenosis caliber up to six months after PTCA with respect to regression or progression as well as to detect factors which possibly influencing the restenosis rate. A computer assisted system with high accuracy was used for two-dimensional quantitation of stenosis. A linear multivariate analysis was applied to quantitative and qualitative angiographic data as well as to clinical findings obtained before, immediately after and six months post-PTCA in 95 consecutive patients in whom 101 stenoses were dilatated. All patients were on a standard medical regimen of aspirin or coumadin and nifedipine. After six months, 56 patients showed a change in minimal stenosis area (mSA) of less than 1 mm2 (no progression), 33 patients showed a decrease in mSA of greater than 1 mm2 which rendered the stenosis with greater than 70% luminal reduction, and 12 patients showed a decrease in mSA of greater than 1 mm2 which did not, however, result in high-grade luminal narrowing. With regard to factors capable of affecting restenosis rate, there was no relationship between extent of dilatation achieved, local dissection, stenosis configuration or localization, calcification, patient age, sex, duration of symptoms, overweight, cholesterol, triglycerides, HDL, LDL, smoking, hypertension or diabetes. However, a relationship was found between the discontinuation of aspirin or coumadin as a result of GI side effects or bleeding (2% no progression; 20% progression). Thus, antiplatelet therapy appears to be important with respect to long-term results after PTCA.

Angina Pectoris

[Carnitine metabolism--changes in the end stage of dilated cardiomyopathy and ischemic heart muscle disease].

Biochemical analyses from endomyocardial biopsies indicate that cardiac energy metabolism is altered in patients with end-stage cardiac failure. Myocardial energy production is predominantly based on fatty acid oxidation. Carnitine, a naturally occurring compound, plays an essential role in fatty acid oxidation by carrying long-chain fatty acids into the mitochondrial matrix where they undergo beta-oxidation. In experimental animals, myocardial carnitine deficiency may cause cardiomyopathies which are reversible with carnitine substitution. Rare human diseases, as systemic carnitine deficiency, are associated with impaired cardiac function. We therefore investigated carnitine metabolism in patients with cardiac failure. Plasma and myocardial carnitine levels were measured in 55 patients undergoing cardiac transplantation because of end-stage cardiac failure based on dilated cardiomyopathy (DC, n = 30) or coronary artery disease (CAD, n = 22). Elevated plasma carnitine levels (controls: 49 +/- 12 microM; DC: 82 +/- 38 microM; p less than 0.001, CAD: 86.9 +/- 21.6 microM; p less than 0.05) were found in both patient groups (Fig. 1). Plasma carnitine did not correlate with creatinine (Fig. 2). Compared to controls, myocardial carnitine levels were significantly reduced: DC: 5.9 +/- 1.45 nmol/mg NCP; CAD: 5.84 +/- 1.84 nmol/mg NCP; controls: 15.6 +/- 5.4 nmol/mg NCP (Fig. 3). No correlation between myocardial and plasma levels was found (Fig. 5).(ABSTRACT TRUNCATED AT 250 WORDS)

Cardiomyopathy, Dilated

Protection of the ischemic myocardium by propionylcarnitine taurine amide. Comparison with other carnitine derivatives.

The cardioprotective effect of the two synthetic carnitine derivatives, propionylcarnitine taurine amide (PCTA) and butyrylcarnitine taurine amide (BCTA), were studied in isolated perfused rat hearts. The protective effects of PCTA and BCTA were compared with those of chemically similar compounds, which have already been investigated in part and reported on; i.e. propionylcarnitine, carnitine, taurine and the combination of propionylcarnitine and taurine. The addition of either PCTA or BCTA significantly improved the recovery of cardiac function of ischemic reperfused hearts. PCTA (0.5 mM) treated hearts regained 75%, 91% and 89% of their preischemic values for cardiac output, left ventricular pressure and dp/dt after 90 min ischemia and 15 min reperfusion. These parameters of cardiac function remained impaired in control hearts which recovered only 38% of the initial preischemic cardiac output, 73% of initial intraventricular developed pressure and 64% of initial positive dp/dt. The cardioprotective effects of PCTA, BCTA and propionylcarnitine were in the same range. However, PCTA and BCTA acted in 20-fold lower molar concentrations compared to propionylcarnitine. Carnitine (11 mM), taurine (11 mM) as well as the combination of propionylcarnitine and taurine at low concentrations had no cardioprotective effect in these experiments. Myocardial adenosine triphosphate (ATP) and creatine phosphate (CP) concentrations were significantly higher in the PCTA or BCTA treated hearts than in controls, and lactate levels were reduced.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Four years of experience in endomyocardial biopsy--an immunohistologic approach.

Left ventricular biopsies from 376 patients (including 78 patients undergoing bypass surgery) were analyzed by light microscopy (necrosis, infiltration with or without fibrosis) and by immunohistology (bound antibodies). Circulating antisarcolemmal antibodies (ASA) were determined at the time of biopsy using a double-sandwich technique. Circulating antimyolemmal antibodies were assessed in intact rat and human cardiocytes. Histologic findings, heart catheterization, and echocardiography together with the patient's history established the diagnosis of perimyocarditis, myocarditis, postmyocarditic dilated cardiomyopathy, healed myocarditis, and healed perimyocarditis. Both bound and circulating ASA were found in up to 100% of cases in acute inflammatory heart disease and postmyocarditic cardiomyopathy, indicating a secondary immunopathogenesis of the myocardial disease. Analysis of immunoglobulin subclasses revealed: IgG-binding does not discriminate between acute/healing/healed carditis and postmyocarditic dilated heart disease (61.1%-91.7% positive); IgM binding is diagnostic for acute or healing perimyocarditis but has a relatively low incidence (33.3%); IgA binding occurs in acute or healing myocarditis (45.5%), perimyocarditis (33.3%), and in postmyocarditic heart disease (39.4%), but not in controls; complement fixation was never seen in controls, but was seen in acute myocarditis (45.4%), perimyocarditis (25%), and postmyocarditic heart disease (46%). Pretreatment of cryostat sections with collagenase to avoid "nonspecific" binding of antibodies to collagen considerably reduced the sensitivity but increased the specificity. Thus, endomyocardial biopsy proved a safe and valuable method for the further analysis of patients with carditis and myocardial disease of unknown origin.

Acute Disease