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Biomedical subjects

E Henze

Publications and source records attributed to E Henze.

At least 109 records · Page 6Linked to original sources
PubMed1987

Nomograms for the prediction of patient's plasma volume in plasma exchange therapy from height, weight, and hematocrit.

The knowledge of plasma volume (PV) is a basic requirement for the standardization of plasma exchange therapy. PV has to be determined by calculation, as the measurement of PV before every plasma exchange is too cost- and time consuming. A known correlation with measured values results from calculation of plasma volume by means of patient's height and weight. But the present equations are only reliable at normal hematocrit. For this reason we modified the Retzlaff-equations and compared the validity of plasma volume predictions, calculated by these and own equations, with plasma volume measured by the 51Cr-method in 59 patients with pathological hematocrit. The correlation coefficient was 0.82 for men and 0.81 for women (2 0.001) with the modified Retzlaff-equations. On the average the relative error was -1.5% for all and 2.8% for fat and thin men. No significant improvement of accuracy was achieved with other equations. Thus, plasma volume can accurately be calculated from height, weight, and hematocrit with our modified Retzlaff-equations in patients with pathological hematocrit, even if they are very fat or thin. Nomograms for men and women were constructed in order to facilitate the calculation.

Blood Volume Determination↗
PubMed1987

Tumor scintigraphy with 131I anti CEA monoclonal antibodies and F(ab')2 in colorectal cancer.

In 14 patients with proven local recurrence of colorectal cancer or metastases in liver and/or lungs, the sensitivity (SE) in detecting tumor sites was estimated in a single-blind study using conventional planar whole body scintigraphy. Nine patients received F(ab')2 and five received MAB by intravenous infusion over 30 min with a dose of 40-200 MBq after skin testing and thyroid blocking, scanning was performed 1-7 days later. All but one patient had elevated plasma CEA levels with a mean of 25.5 +/- 31.9 ng/ml. The scans were interpreted by two independent observers. In five of the nine patients receiving F(ab')2, the tumor site could be visualized, yielding a sensitivity of 55%. No tumor sites were identified with MAB. The highest tumor uptake was recorded in a patient with additional ovarian cancer with the activity accumulating in the ovarian cancer. The optimum time for imaging was 3 or 4 days after injection. There was no correlation between positive imaging and plasma CEA levels which ranged from 1.9 ng/ml to 100 ng/ml in the positive cases. The thyroid uptake on the sixth day was 0.68% +/- 0.2% of the total dose given despite thyroid blocking. Bone uptake of 131I was also observed, this was mild in four patients, moderate in three but high in one patient, especially on days one to four. Thus, only anti-CEA F(ab')2 seem to be of clinical interest for further evaluation in localizing colorectal cancer. Regarding the still low sensitivity of 55%, further improvement can be expected by gaining experience, using more appropriate isotopes such as 111In and SPECT. The estimated radiation side effects on thyroid and bone marrow are only modest.

Aged↗
PubMed1987

[Positron emission tomography of the heart].

Positron emission computed tomography (PET) has introduced a new dimension into cardiology by its ability of imaging in-vivo cardiac metabolism non-invasively. Following administration of labelled substrates PET provides display of digitized heart tomograms, which reflect tracer concentration quantitatively. Thus, regional myocardial metabolism and perfusion can be measured using appropriate tracers such as C-11 palmitate, F-18 deoxyglucose, N-13 or C-11 amino acids, N-13 ammonia and Rb-82. Accordingly, the documentation of marked metabolic derangements during ischemia and infarction by initial clinical PET studies have been very promising diagnostically. It has been shown that normal, resting ischemic and acutely ischemic and infarcted tissue can be differentiated reliably. In cardiomyopathies, disturbed energy substrate utilization not known until then was found by means of PET. Unfortunately, PET will be available only in larger centers in the near future because of its high cost.

Coronary Circulation↗
PubMed1986

Left heart function in chronic obstructive lung disease.

In patients with varying degrees of chronic obstructive pulmonary disease (COPD), simultaneous measurements of central hemodynamics and left ventricular radionuclide ventriculograms at rest and during exercise were made. In 21 of these patients, satisfactory echocardiograms could be performed. In seven of the patients, arterial blood pressure at rest was increased. Decreased compliance of the left ventricle was thought to be present in patients with COPD and additional arterial hypertension. The left ventricular ejection fraction (LVEF) at rest was in the high normal range in all patients. During exercise, no further increase was observed. This pattern of LVEF response seems to be typical in patients with COPD. Because the highest values were observed in the more severe COPD and right ventricular hypertrophy, it is unlikely that an impairment of left ventricular function is caused by COPD. In five of 27 patients, an abnormal decrease of LVEF and regional hypokinesis occurred during exercise, thus suggesting additional coronary heart disease. The fact that at least 30% of the patients with COPD suffered from arterial hypertension and 20% of the patients exhibited unexpected ischemia detected by regional hypokinesis in RNV during exercise, but not in the ECG, may be of practical relevance. Coronary angiography was not indicated because most of these patients were over 65 and the factor limiting the working capacity was ventilatory impairment and not angina pectoris, in all patients. For this reason, a diagnostic uncertainty remains with regard to additional coronary heart disease in the older patients with advanced chronic obstructive pulmonary disease.

Aged↗
PubMed1986

Studies of fatty acid metabolism with positron emission tomography in patients with cardiomyopathy.

Positron emission tomography (PET) permits in vivo as well as noninvasive study of fatty acid metabolism. Parameters of 11C-palmitate kinetics relate to the oxidation of fatty acids, and palmitic acid uptake is impaired in patients with coronary disease and cardiomyopathy. Normal myocardium shows homogeneous fatty acid metabolism and can resort to alternate substrates. Diseased myocardium exhibits regional heterogeneity in fatty acid uptake and utilization. In patients with cardiomyopathy, distinct patterns of fatty acid metabolism can be observed following changes of substrate availability by application of an oral glucose load. This intervention also enhances the heterogeneity of 11C-palmitic acid (CPA) uptake and clearance. Thus, PET studies with CPA permit the noninvasive demonstration of effects on substrate availability and may help to characterize patients with ventricular dysfunction on the biochemical level.

Adult↗
PubMed1986

Diagnostic value of early and delayed 201Tl thyroid scintigraphy in the evaluation of cold nodules for malignancy.

We performed 201Tl thyroid scintigraphy using an early and delayed scanning technique in 34 patients exhibiting cold nodules on 99mTc scans. Of the 29 benign nodules, 27 were correctly diagnosed as being negative, i.e. 93% specificity. However, two of five malignant nodules failed to concentrate activity on both the early and delayed scans. The low sensitivity (60%) of this method for detecting carcinomas limits its clinical value in the routine diagnostic work-up of patients with suspected thyroid cancer. Our findings are in contrast to previous more optimistic reports.

Adult↗
PubMed1986

Effects of substrate availability on myocardial C-11 palmitate kinetics by positron emission tomography in normal subjects and patients with ventricular dysfunction.

The possibility of demonstrating noninvasively with C-11 palmitate and positron emission tomography (PET) changes in myocardial substrate metabolism in normal and diseased human myocardium in response to altered substrate availability in blood and disease-related abnormalities was examined in five normal volunteers and 16 patients with ventricular dysfunction. C-11 palmitate injection and serial PET imaging were performed after an overnight fast (control period) and again 2 hours later after oral glucose (50 gm). Myocardial C-11 time-activity curves from serial PET images revealed a biexponential clearance pattern. An early rapid phase, defined by relative size and clearance half-time, reflects C-11 palmitate oxidation and the late slow phase tracer deposition in the endogenous lipid pool. During the control period, the tracer fraction entering the early rapid phase averaged 47 +/- 13% (SD) in normal subjects and 45 +/- 12% in patients. Corresponding clearance half-times were 19 +/- 7 and 20 +/- 5 minutes, respectively. Heart rate and blood pressure remained unchanged after glucose, but plasma glucose levels rose by 72.5% in normal subjects and by 98.9% in patients, while free fatty acid levels fell by 72% and 42% (p less than 0.001), respectively. In normal subjects, the tracer fraction in the early rapid phase fell by 43% (p less than 0.005) and the clearance half-time increased by 46% (p less than 0.01). In patients, the response of C-11 palmitate tissue kinetics to glucose was variable. In nine patients, it was similar to that in normal subjects while in the other seven patients a "paradoxic" response occurred. The tracer fraction entering the rapid clearance phase increased after glucose by 30% (p less than 0.05) associated with a 36% (p less than 0.05) decline in clearance half-times. The paradoxic response was unrelated to disease etiology or plasma substrate levels but occurred mostly in left ventricles with more severely depressed function. Thus, PET and C-11 palmitate allow the noninvasive demonstration of the known response of substrate metabolism of the human heart to altered substrate availability. Glucose administration in fasted humans serves as a provocative test of substrate regulation which can be abnormal in myocardial disease and can be demonstrated noninvasively.

Adult↗
PubMed1986

Haemodynamic response to exercise in patients with chest pain and normal coronary angiograms.

A series of 42 patients with chest pain but normal coronary angiograms and normal haemodynamics at rest were prospectively classified as typical angina (group 1, N = 9) or atypical angina (group 2, N = 16) or non-anginal chest pain (group 3, N = 17). All patients underwent radionuclide ventriculography and measurement of pulmonary artery pressure at rest and during maximum exercise. Comparison of data during exercise revealed significantly higher (P less than 0.025) left ventricular filing pressures as reflected by the diastolic pulmonary artery pressure in group 1 (29 +/- 5 mmHg) than in both group 2 (22 +/- 6 mmHg) and group 3 (22 +/- 5 mmHg). The rest-to-exercise change in left ventricular ejection fraction was variable and not significant in group 1 (62 +/- 6% vs 63 +/- 14%). By contrast, both group 2 and group 3 had significant increases (63 +/- 6% vs 69 +/- 10%, P less than 0.02 and 63 +/- 5% vs 68 +/- 5%, P less than 0.01). The classification as 'typical angina' was predictive of an abnormal (greater than 25 mmHg) filling-pressure response to stress. The positive and negative predictive values were 78% and 70%, respectively. The clinical classification was not a predictor of an abnormal (delta less than 5%) ejection-fraction response. No correlation between radionuclide and filling-pressure data could be established. The data suggest that the majority of patients assigned to group 1 manifested an impaired left ventricular function with exercise. This was primarily related to abnormalities in diastolic filling while the systolic performance was not consistently depressed.

Adult↗
PubMed1986

Interactions of vasodilators with calcium entry- and beta-blockers in patients with coronary heart disease.

Combinations of antianginal drugs may be used for an additive effect against angina, but also to off-set unwanted effects of one drug with another, either by direct effects or by a reduction of dosage of each drug. Based on earlier studies with separate drugs we have now examined the effect of 150 mg bupranolol combined with 40 mg isosorbide dinitrate (ISDN) in one retarded tablet, given twice daily. 22 patients with CHD entered the study, 11 of those with and 11 without signs of ischemia during exercise. In an acute radionuclide ventriculographic (RNV) study 2 h after the tablet, ejection fraction (EF) during exercise increased only in patients with exercise ischemia (+6%, p less than 0.001). In the other patients EF did not change. After 21 days of treatment echocardiographically determined end-systolic and end-diastolic diameters decreased, resulting in an increase of shortening fraction by 15.6% (p less than 0.05). Heart rate, systolic and diastolic pressure and ST-segment depression decreased significantly. In another acute RNV study the effect of a venous vasodilator, molsidomine 4 mg s.l., was examined after nifedipine 10 mg s.l. in 19 patients with CHD, 9 with and 10 without exercise ischemia. Differences between drugs were most prominent during exercise. In the nonischemic group EF rose by 6.6% after nifedipine (n.s.) and by 14% after molsidomine (p less than 0.01 against control). In the group with ischemia EF rose by 12.6% after nifedipine and by 17.4% after additional molsidomine, significant against control (p less than 0.01) as well as against nifedipine (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Bupranolol↗
PubMed1986

Parametric imaging of experimentally simulated Wolff-Parkinson-White syndrome conduction abnormalities in dogs: a concise communication.

In order to test the diagnostic potential of phase analysis of radionuclide ventriculography (RNV) for localizing accessory bundles in Wolff-Parkinson-White (WPW) syndrome, 24 experimental runs were performed in three open chest instrumented dogs. After a baseline study, WPW syndrome was simulated by stimulation at seven different sites around the base of the ventricles, and RNV's were obtained. Subsequent data processing including Fourier transformation allowed the localization of the site of the first inward motion of the ventricles by an isophasic wave display. In sinus rhythm, the septum contracted first. During ectopic premature ventricular stimulation by triggering the atrial signal, the phase scan was altered only when the stimulus was applied earlier than 20 ms before the expected QRS complex during sinus rhythm. During stimulation with fixed frequency, only the left lateral positions of the premature stimulation were detected by phase analysis with a sensitivity of 86%. Neither the antero- or posteroseptal nor the right ventricular premature contraction pattern could be exactly localized.

Animals↗
PubMed1986

Specification of regional wall motion abnormalities by phase analysis of radionuclide angiograms in coronary artery disease and non-coronary artery disease patients.

Fourier transform of gated radionuclide ventriculograms (RNV) permits the quantitative evaluation of regional wall motion abnormalities (RWMA) regarding both regional magnitude (amplitude display) and regional time sequence of contraction (phase display). In this study, an attempt was made to further specify coronary artery disease (CAD) and non-CAD RWMA detected on consecutive exercise RNV in 17 patients (pts) with proven severe CAD; or on resting RNV in 24 pts with transmural myocardial infarction (MI) compared with 27 pts after treatment with daunorubicin (DAU). RWMA were defined objectively from parametric images by a decrease of the sectorial amplitude by more than 2 s.d.s of normal as determined by quantification of RNV studies of 20 normal individuals. In 15 out of 17 CAD pts (88%) and in 19 out of 24 MI pts (79%), a significantly decreased regional amplitude was found. Importantly, in all abnormal CAD and MI amplitude scans (100%), a significantly abnormal phase delay in the same region could be noted. In five out of 27 pts on DAU (18%) an apical hypokinesis could be verified. In comparison with CAD pts, however, the phase distribution was normal in all these DAU pts. Thus, standardized phase analysis of RNV data provides a powerful tool for specifying RWMA. It allows a highly specific separation of RWMA caused by exercise-induced ischemia, MI, or DAU.

Adult↗
PubMed1985

Right ventricular function in patients with chronic obstructive pulmonary disease.

Simultaneous right heart catheterization and radionuclide ventriculography were performed in 27 patients with a wide range of chronic obstructive pulmonary disease. Central hemodynamics and radionuclide studies were done at rest and during exercise. In the resting state the right ventricular ejection fraction (RVEF) was in the normal range (43.3 +/- 6%). During exercise a significant (p less than 0.001) decrease of RVEF to 38.8 +/- 6.7% occurred. The pulmonary artery mean pressures were 19.9 +/- 3.8 at rest. During exercise a significant (p less than 0.001) increase to 41 +/- 9.8 mm Hg occurred. There was a linear relationship between pulmonary pressures and RVEF during exercise in patients with pulmonary artery pressures not exceeding 35 mm Hg. In patients with right ventricular end-diastolic wall thickness greater than or equal to 6 mm a curvilinear relationship between these parameters could be observed with a flattening of the curve at higher pressures (greater than 35 mm Hg) and lower ejection fractions (less than 35% RVEF). Radionuclide ventriculography cannot substitute for right heart catheterization. Echocardiography is useful for interpretation of right ventricular ejection fractions in advanced chronic obstructive pulmonary disease.

Aged↗
PubMed1985

An evaluation of the diagnostic efficacy of phase analysis of data from radionuclide ventriculograms in patients with Wolff-Parkinson-White syndrome.

It has been suggested that phase analysis of radionuclide ventriculograms may be of value for detecting and localising the abnormal sequence of ventricular contraction secondary to Wolff-Parkinson-White (WPW) syndrome. The present study was undertaken to test this hypothesis. The space--time sequences of right- and left-ventricular action obtained from radionuclide ventriculograms obtained during rest studies were evaluated in 8 patients with WPW syndrome (confirmed by 12-lead surface electrocardiography) and compared to those of 14 normal subjects. All of the latter showed a consistent ventricular activation pattern, i.e. the first site of ventricular activity in the upper septal region followed by a second site either at the base of the left ventricle or located apically. It was possible to diagnose 11 of the 14 normal subjects (specificity, 79%) and 7 of the 8 patients (sensitivity, 88%). The 4 patients who had been classified as having a left-sided accessory bundle by surface electrocardiography were likewise diagnosed by phase analysis, as were the 2 patients with a confirmed right-sided bypass tract. Two patients with septal posterior accessory pathways could not be identified by phase analysis. Furthermore, cases with an activation pattern which closely resembled that of the 2 patients with right-sided accessory bundles were found to be normal from their ECGs. It is now necessary to evaluate phase analysis against invasive electrophysiological methods in such patients.

Electrocardiography↗
PubMed1985

Measurement of regional myocardial blood flow with N-13 ammonia and positron-emission tomography in intact dogs.

N-13 ammonia mimics certain properties of microspheres. It rapidly clears from blood into myocardium where it becomes fixed in proportion to myocardial blood flow. Used with positron emission tomography as a means for quantifying in vivo myocardial indicator concentrations, N-13 ammonia may be useful for noninvasive determination of myocardial blood flow with the arterial reference sampling technique. This possibility was examined in 27 experiments in 10 chronically instrumented dogs at control, high and low blood flows. Myocardial blood flow was calculated in vivo from the myocardial N-13 tissue activity concentrations derived from serial cross-sectional images of the heart, the 2 minute arterial input function and the withdrawal rate of arterial blood. These calculations were compared with blood flow determined by the standard microsphere technique. Blood flow determined in vivo with N-13 ammonia and positron emission tomography correlated with microsphere blood flow by y = -36.2 + 1.53x -0.0027x2 (r = 0.94 with a standard error of the estimate of 16 ml/min per 100 g). For flows from 44 to 200 ml/min per 100 g, the relation between in vivo and in vitro measured myocardial blood flow was nearly linear but reached a plateau at flows higher than 200 ml/min per 100 g. These results indicate that in dogs, blood flow in the physiologic range can be quantified in vivo with N-13 ammonia and positron emission tomography.

Ammonia↗
PubMed1985

Limitations of radionuclide ventriculography in the non-invasive diagnosis of coronary artery disease. A correlation with right heart haemodynamic values during exercise.

A consecutive series of 56 patients with chest pain but no evidence of previous myocardial infarction was prospectively studied by radionuclide ventriculography to determine the value of global and regional radionuclide indices in detecting coronary artery disease. The results were correlated with the clinical judgment of chest pain, the results of the exercise electrocardiogram, and the right heart haemodynamic measurements during exercise. As a result of the criteria for entry, the study group was representative of the population seen in such a clinical setting. Only 25% of patients had coronary artery disease. The predictive power of radionuclide ventriculography was limited. The conventionally used criterion that normal subjects have an increase in left ventricular ejection fraction of at least 5% with exercise provided only 78% sensitivity and 57% specificity. Fourier analysis and visual interpretation of radionuclide studies wrongly diagnosed three out of 10 patients with extensive disease requiring surgery. These results suggest that radionuclide ventriculography is of limited value in the non-invasive diagnosis of coronary artery disease.

Adult↗
PubMed1985

Functional asplenia in malignant mastocytosis.

A 47-yr-old man with malignant mastocytosis, a malignant neoplasia of mast cells, presented with anemia. Ultrasonography revealed an enlarged spleen. A liver-spleen scan using [99mTc]sulfur colloid failed to show any splenic uptake consistent with the diagnosis of functional asplenia. Functional asplenia related to this condition has not been reported previously. Since the spleen was heavily infiltrated with space occupying mast cells, a mass displacing effect along with impaired perfusion are discussed as underlying mechanism.

False Negative Reactions↗
PubMed1984

Primary hemochromatosis: anatomic and physiologic characteristics of the cardiac ventricles and their response to phlebotomy.

M-mode and 2-dimensional echocardiography and gated equilibrium blood pool imaging (rest and exercise) were used in 10 patients with primary hemochromatosis to characterize the spectrum of pathophysiologic abnormalities of the cardiac ventricles and to determine the response to chronic therapeutic phlebotomy. Dilated and restrictive cardiomyopathic patterns were identified in 1 patient each, but our data do not permit conclusions on when in the natural history a given pattern becomes overt. On entry into study, 3 patients had normal ventricles and 7 had ventricular abnormalities on echocardiography and blood pool angiography. In 2 of the latter patients, biventricular dysfunction and increased left ventricular (LV) mass normalized after phlebotomy; 1 patient achieved a normal LV response to exercise. Of the 4 patients with isolated abnormal LV ejection fraction responses to exercise, the EF normalized in 2 after phlebotomy. In 1 patient, isolated right ventricular enlargement and dysfunction (echocardiographic and radionuclide imaging) normalized after phlebotomy. Thus, primary hemochromatosis can effect LV and RV size and function; clinically occult cardiac involvement can be identified by echocardiography and equilibrium blood pool imaging; therapeutic phlebotomy can ameliorate or reverse the deleterious effects of excess cardiac iron deposition which appears to exert its harm, at least in part, by a mechanism other than irreversible connective tissue replacement.

Adult↗