Indium-111 monoclonal antimyosin for diagnosis of cardiac rejection.
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Biomedical subjects
Publications and source records attributed to C Spes.
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In a combined pharmacokinetic and clinical trial the correlation was investigated between plasma levels of oxilofrine and the haemodynamic effects on eight healthy volunteers after an oral dose of 120 mg oxilofrine. Plasma levels of free oxilofrine were measured by capillary gas chromatography mass fragmentography. Cardiovascular as well as echocardiographic parameters (left ventrical extent and velocity of fractional shortening) have been measured. The results pharmacokinetically showed a marked enterohepatic reabsorption profile with a second oxilofrine plasma peak occurring in between the second and third hours. The heart rate and mean arterial blood pressure remained unchanged. The total peripheral resistance was deceased on average. Systolic blood pressure increased by a maximum of 13.8%, the diastolic decreased by 8.8%. Increasing of the extent of left ventrical fractional shortening by 20.9% and the velocity by 29.5% indicated a positive inotropic effect, which was long lasting and not accompanied by chronotropic effects. There is a direct positive correlation between oxilofrine plasma levels and the extent of fractional shortening of left ventrical diameter (r = 0.981).
Autopsy studies have shown that cardiomyopathy of Duchenne's muscular dystrophy (DMD) is characterized by fibrosis of the posterobasal and contiguous lateral wall of the left ventricle. This study was designed to determine whether stress testing would improve the sensitivity of echocardiography to detect secondary impairment of regional myocardial function. 12 patients aged 5 to 23 years with DMD were investigated. TM- and 2D-echocardiograms were performed before and during graded infusion of angiotensin (A) (0.5 to 5.0 mcg/min), and parameters of cardiac function analyzed. Satisfactory echocardiograms were obtained in all patients. Stress testing with A proved feasible in DMD and did not interfere with echocardiography. Before A all patients were in regular sinus rhythm and free of cardiac symptoms. Left ventricular function was normal in 9 patients and considered abnormal in 3 patients with hypokinesis and increased echo intensity of the posterobasal and lateral wall (2D short axis view) and/or a posterior wall to septal amplitude ratio of less than or equal to 1.1 (TM-echocardiogram). During A mean blood pressure rose and heart rate dropped significantly. 9 patients had marked supraventricular arrhythmias, 8 complained of dyspnea, cough or chest pain. Hypo- or akinesis of the posterobasal and sometimes the lateral wall was seen in 8, and a posterior wall to septal amplitude ratio of less than or equal to 1.1 in 9 patients. 3 patients, all with a muscle score of 60% or higher, remained free of symptoms and had no regional contraction abnormalities. Thus, clinical symptoms during A suggested latent congestive heart failure in many of the patients, and echocardiography identified provokable contraction abnormalities of such segments of the ventricular wall known to be most frequently involved in the dystrophic process in DMD. Stress testing revealed a correlation between clinical symptoms, abnormal echocardiographic findings and extent of the skeletal muscle disease in our study group. Physical limitation seems to protect the heart against demands that would otherwise cause earlier clinical manifestation of the cardiomyopathy in DMD.
Sixty-eight indium 111-labeled antimyosin Fab-DTPA imaging studies (0.5 mg intravenously with a radioactivity of 65 to 75 MBq) were executed on 37 of 116 patients undergoing heart transplantation to assess diagnostic accuracy and clinical utility. As controls, 21 patients with cardiomyopathy (n = 8), unstable angina (n = 9), and myocardial infarction (n = 4) were selected. After 48 hours, single photon emission computed tomographic images were evaluated visually, and heart/lung ratios were measured, using the "region of interest" technique. They were compared with echocardiographic and endomyocardial biopsy results. In 40 studies a heart/lung ratio less than or equal to 1.6 corresponded to a negative biopsy result in 98% (40/41). Echocardiography enabled correct identification of 95% of the patients with normal biopsy findings. In 91% (22/24) a positive biopsy finding correlated with a heart/lung ratio greater than 1.6 including 20 mild rejections, but in only 64%, with an increase in wall thickness and/or decrease of fractional diameter shortening seen on echocardiogram. In addition, the various stages of rejection episodes determined the amount of the heart-lung ratio. There was a significant relationship between the histologic findings and the antimyosin uptake. In 13 patients a second investigation was performed after rejection therapy. All patients had a negative biopsy result, and the heart/lung ratio decreased to normal ranges (less than or equal to 1.6). Five antimyosin antibody studies were excluded, as in these cases, negative uptake results were found during rejection therapy with high-dose steroids. The overall sensitivity was calculated at 93% and the specificity at 98%.(ABSTRACT TRUNCATED AT 250 WORDS)