Search

Electrocardiograms and radionuclide ventriculograms were obtained at rest and on exercise in 23 patients (20 men and 3 women, mean age 53.4 years) with exercise-dependent myocardial ischaemia after infarction, as well as in 22 persons (17 men and 5 women, mean age 43 years) without clinical, electrocardiographic and biochemical evidence of coronary heart disease. Among the ischaemia patients exercise-dependent loss of motility, as measured by regional ejection fraction and Fourier amplitude, occurred in 95% (50% of controls) in one sector, in 78% (4.5% of controls) in the two sectors with the highest contractility at rest, and in 74% (0% of controls) in three sectors. On exercise, phase shifts occurred in 87% (27% of controls). When combining the exercise-ECG, global ejection fraction as well as regional motility loss in one sector, in the two sectors with the highest contractility at rest and in three sectors, at least two of the five criteria of abnormality were present in 91.3% of the ischaemia patients, compared with at most one criterion in 90.9% of controls. The results indicate the greater diagnostic value of regional than global measures of ventricular function and emphasize the importance of radionuclide ventriculography as an addition to exercise electrocardiography in the pre-invasive diagnosis of coronary heart disease.

The effect of saralasin, a competitive inhibitor of angiotensin II, was assessed in hypertensive patients with unilateral renal artery stenosis after furosemide application. A significant fall of systemic arterial blood pressure, an increase of renal venous renin activity, significantly on the stenosed side in patients without arteriosclerosis of the contralateral kidney, and an almost equal decrement of renal blood flow in both kidneys were observed. Conceivably saralasin exerts different sodium-dependent effects on peripheral angiotensin II and specific intrarenal vascular receptors.

Arrhythmogenic substrate diagnosis has been achieved by electrophysiological studies and best localized by successful radiofrequency ablation. Pre-invasive localization procedures have been based on surface ECGs and more recently on biomagnetism, but in addition to these electric and magnetic signals a mechanical signal may be utilized: the initial site of contraction may be detected by phase analysis during radionuclide ventriculography. Generation of three-dimensional data set of phases is achieved by incorporating the new emission tomography technique. The performance of this modified phase analysis has been investigated for the detection of the normal contraction pattern during sinus rhythm, the arrhythmogenic substrate of the WPW syndrome and ventricular tachycardia, and further, to define the limitations of the method in experimental studies on pigs. In 30 out of 44 patients with normal sinus rhythm and no ventricular lesion, a characteristic phase pattern was found. Physiologically, the initial site of contraction appeared to be paraseptal and in the anterior wall of the right ventricle close to the apex. In 13 patients with WPW syndrome and in seven with ventricular tachycardia, the phase data were compared to the electrophysiological study. In 14 of 20 there was a complete match, in 3 of 20 a mechanical focus was found in the area adjacent to the electric focus. From experimental pig studies with simulated stimulation, a spatial precision of at least 20 mm was found at a pre-excitation of 20 ms.(ABSTRACT TRUNCATED AT 250 WORDS)

The quantification of myocardial perfusion abnormalities is necessary to allow comparison of repeated studies, especially in the evaluation of the success of medical, interventional or combined treatment in stable coronary artery disease or in evolving myocardial infarction. The purpose of this study was to assess inter-observer reproducibility of tomographic study processing using a semi-automatic quantitative programme. Technetium 99m hexakis-2-methoxyisobutylisonitrile (99mTc-Sestamibi) was chosen for tomographic imaging of repeated rest-stress studies in patients with stable coronary artery disease. The quantification was performed using a modification of the Cedars polar coding and comparison with the normal data base. The perfusion defects were quantified separately for each standard perfusion area [left anterior descending (LAD), right coronary (RCA) and left circumflex (LCX) arteries] and total area of hypoperfused myocardium. The inter-observer variability for 40 tomographic studies was accomplished. The defects were the largest in the LAD perfusion area (average 19.7% of the normalized LAD supply area) with an inter-observer correlation of 0.84 for this region. The greatest variability was found for the LCX region (r = 0.55) and is attributed to a small average perfusion defect (7.1%), only 18 studies having abnormal perfusion in this area. In total, an average 14.3% of the left ventricular myocardium was significantly hypoperfused, and the inter-observer correlation was 0.87. These results show good inter-observer reproducibility using semi-automatic quantitation of perfusion defects. Careful interpretation of smaller defects in the evaluation of treatment results is advised when repeated 99mTc-Sestamibi single photon emission tomography studies are processed by more than one observer.

Das philosophische Motto begrundet die fundamentale Bedeutung der „Anschauung“ d. h. die Bedeutung von Bildern, seien es die unmittelbar erfassten oder artefiziell „gegebenen“. Die Wissenschaft hat uns vor und seit der Grundung unserer Gesellschaft durch eine Fulle Bild-gebender Verfahren die Augen fur die inneren Strukturen unseres Korpers geoffnet und uns dadurch Moglichkeiten eroffnet, verborgene, biologische und physikalische Aspekte der Herz- und der Kreislauffunktion darzustellen und zu erforschen: a) unterschiedliche Absorptionseigenschaften der Gewebe fur Rontgenstrahlen, b) differente Widerstande oder Impedanzen fur Ultraschallschwingungen, c) induzierbare magnetische Resonanzen kardiovaskularer Strukturen und d) die Verteilung und Stromung radioaktiver Indikatoren in Blut und Gewebe.

A new tomographic technique combined with phase analysis was used to detect premature and ectopic ventricular contraction patterns in 15 patients with Wolff-Parkinson-White syndrome and during ventricular tachycardia in seven patients. Data generated by gated single-photon emission computed tomography (SPECT) were analysed by backprojection of the Fourier coefficients, double-angulation, and integration to thick slices containing the ventricles, thus allowing visualisation of the contraction patterns in three perpendicular views. The results were compared with those of catheter mapping. In nine patients with Wolff-Parkinson-White syndrome the site of initial contraction detected was identical with the site of the accessory pathway found by catheter mapping. The sites of origin of the ventricular tachycardias determined by catheter mapping were within 3 cm of the sites detected by the new technique. This new technique seems to be a promising non-invasive method for localising ectopic ventricular activity that will considerably shorten the time required for subsequent invasive procedures.

A data base of clinical studies is required for quality assurance of software used for analysis of radionuclide cardiac imaging procedures. Studies used must be rigorously validated in terms of both the clinical condition of the patient undergoing the procedure and the imaging protocol used. Selection protocols for the creation of a software phantom data base of normal studies and three typical patterns of cardiac disease--recent transmural myocardial infarction, isolated myocardial ischaemia and dilated cardiomyopathy--have been developed by the Cardiac Working Group of the European COST B2 project in association with the Cardiac Task Group of the European Association of Nuclear Medicine and the Working Group on Nuclear Cardiology of the European Society of Cardiology. These protocols include criteria for the interpretation of qualitative and quantitative non-radionuclide data. Compliance of the clinical data with the selection criteria will have to pass scrutiny by an international team for each study used as a software phantom. The radionuclide studies encompass stress and rest myocardial perfusion studies (planar and single photon emission tomography) using thallium-201 and technetium-99m methoxyisobutylisonitrile and rest gated blood pool studies. Methods for acquisition of data are defined for each type of study and for each individual study a portfolio of all clinical data is established. A pilot study is required to investigate the problems and logistics of distributing clinical radionuclide studies between a range of computers and institutes, and to ascertain the procedures necessary for analytical comparison of the results obtained.

The upward creep of the heart during myocardial single photon emission tomography (SPET) acquisition has been reported as a frequent source of false-positive results. The aim of this study was to simplify the detection and correction of this upward creep and to estimate its clinical relevance during routine patient care. To recognize the upward heart motion a straight line was fitted to the upper and lower border of consecutively displayed tomographic projection images. In this way, vertical translation of at least 1 pixel in size could be detected easily. On the assumption of a slow but continuous upward motion a fast interpolation correction method was developed. From 100 consecutive, supine, ergometric exercise studies, 1, 2 or 3 pixels of upward creep were found in 16, 4 or 3 patients, respectively. It was found that an upward creep of at least 2 pixels (7/100 cases) led to evident, mostly antero-septal defects on quantitative bull's-eyes, whereas only upward creeps of 3 pixels or more (3/100 cases) produced false-positive diagnostic results. The simple correction method offered a sufficient compensation of image and/or bull's-eye artefacts. These clinical findings could be reproduced in a computer model. Thus, it can be stated that clinically significant upward creep of the heart during stress SPET acquisition is relatively rare; it may have been overestimated in the past, and its artificial effects can be corrected by a quick and simple algorithm.

Currently the images of nuclear medicine institutions are stored on magnetic media. The documentation is done with hardcopies. Officially magnetic media are not accepted for documentation purpose and hardcopies do not allow further processing. The access to the original data is time consuming and personal intensive. There is a demand to store at least the original information cheaply, safely and direct accessibly. The appearence of the optical disks together with a jukebox facilitates digital archives at least for nuclear medicine. As a prerequisit it is necessary to connect all imaging devices through its data systems within a nuclear medicine institution to a local area net (LAN) forming a PACS (Picture Archiving and Communication System) Data compatibility must be fulfilled as well as a positive patient identification. Quality controls must provide for data security and reliability. An effective retrieval system must serve for fast access to the archives. PACS and RIS (Radiological Information System) must built a unified system. Such a local net in addition should be connected to the HIS (Hospital Information System) in order to reduce the administration work in nuclear medicine. A prototype of a nuclear medicine system is in use at the University of Ulm since 1988, wich will be hooked to the HIS in 1990. Since PACS currently is developed mainly for the other modalities (CT, MR, DSA, DR) through the industry, nuclear medicine should participate in this development with its particular needs.

The availability of the public broadband telecommunication network from the Deutsche Bundespost Telekom based on the already existing interim fibre optic broadband network allows data transmission at rates of up to 2 MBit/s simultaneously with videoconferencing (140 MBit/s). We aimed two goals: 1. Realization of a point to point auto-dialing connection of the two Nuclear Medicine LAN’s (Ethernet) in Bonn and Ulm. This LAN connection allows digital interuniversity image distribution in real time in order to collect well documented clinical demonstration cases in the digital archives maintained in Ulm. A catalog comprising scintigraphic images from all fields of diagnostic nuclar medicine is beeing build by means of the large storage capacity provided by a jukebox with optical disks allowing direct access for updating as well as for demonstration and teaching. 2. Development and testing of broad band telecommunicaton protocols for interuniversity conferences of clinical case presentation by means of a direct link of scintigraphic workstations simultaneously with videoconferencing.

Since catheter or surgical techniques for ablating the arrhythmogenic substrate in patients with SVT due to accessory pathways or those with VT are now available, exact localization of the substrate is mandatory. We report preliminary results of two new non-invasive techniques for localizing either the site of earliest ventricular contraction using ISPECT, or the site of initial ventricular depolarization by magnetocardiography (MCG) in WPW syndrome and in VT patients. Thirteen patients with WPW syndrome and 8 patients with sustained VTs were studied with ISPECT. In 9/13, comparative catheter mapping data were available. Two patients had two Kent bundles. 13/15 Kent bundles could be localized by ISPECT. In 5/9 patients the area of Kent bundle insertion was identical with ISPECT and catheter mapping, in 3 correlation was fair, and in 2 patients with 2 Kent bundles ISPECT failed to localize their insertion. In 3/8 patients with VT catheter mapping could not be performed for hemodynamic reasons. In 2/5 patients the area of VT focus was identical with both methods, in one patient it was adjacent to each other, and in 2/5 patients a larger anatomic distance of the focus was found with both methods. In 3/7 patients with WPW the MCG showed the site of Kent bundle insertion, which was identical to that seen by catheter mapping. In one patient the area was adjacent, and in 3 more distant from the site determined by catheter mapping. In 1/2 patients with 2 Kent bundles, one of these could be detected by MCG. In 1/3 patients with VT, the site of VT focus was identical with both methods, but in the remaining two a distance of 3–4 cm was observed between the area seen with MCG and that with catheter mapping. In 4 further VT patients with stable and uniform ventricular late potentials, ventricular late magnetic activity was found with different QRS lengths within the single MCG channels. From our results we conclude that both ISPECT and MCG seem to become very promising non-invasive techniques for localizing ectopic ventricular depolarization in WPW syndrome and VT patients. However, these methods have to be refined, improved and validated by further systematical studies.

A carbon-14 (14C) urea breath test for detecting Helicobacter pylori with multiple breath sampling was developed. Carbon-14-urea (110 kBq) administered orally to 18 normal subjects and to 82 patients with Helicobacter infection. The exhaled 14C-labeled CO2 was trapped at 10-min intervals for 90 min. The total 14C activity exhaled over 90 min was integrated and expressed in %activity of the total dose given. In normals, a mean of 0.59% +/- 0.24% was measured, resulting in an upper limit of normal of 1.07%. In 82 patients, a sensitivity of 90.2%, a specificity of 83.8%, and a positive predictive value of 90.2% was found. The single probes at intervals of 40-60 min correlated best with the integrated result, with r ranging from 0.986 to 0.990. The test's diagnostic accuracy did not change at all when reevaluated with the 40-, 50-, or 60-min sample data alone. Thus, the 14C-urea breath test can be applied routinely as a noninvasive, low-cost and one-sample test with high diagnostic accuracy in detecting Helicobacter pylori colonization.

Gated SPECT (GASPECT) during radionuclide ventriculography (RNV) is a time-consuming procedure requiring extended hard- and software. Furthermore, the procedure suffers from poor count statistics. Our method tries to overcome these difficulties by exploiting the count summation effect of Fourier analysis. The sine and cosine coefficients of the first harmonic are extracted from the gated views and reconstructed. This, in fact, results in an improvement of the count statistics by a factor of four combined with a tremendous reduction of disc space requirements. Using short-axis slices, bull's-eye plots of the amplitude and phase of the left ventricle are calculated. Cardiac functions and localization and extent of any malfunction are documented three-dimensionally without superposition.

In planar radionuclide ventriculography (RNV) identification of the site of initial contraction is possibly by the Fourier phase. First clinical experiences will be presented with a new integrated tomographic technique--ISPECT--in noninvasively assessing the site of ectopic or premature ventricular depolarization. In six patients Fourier phases of RNV and ISPECT were performed and compared in five with results from the corresponding electrophysiologic study. It was possible to exactly localize the beginning of mechanical contraction in the two orthogonal planes: during pacemaker stimulation at the apex of the right ventricle, at the lateral border of a large aneurysm during ventricular tachycardia, and at the site of three of five WPW bundles. In the other two bundles the site of first contraction was near the area found during invasive mapping procedure. Thus, this new ISPECT approach together with planar radionuclide imaging may help in noninvasively localizing the site of ectopic and premature depolarization in addition to surface ECG.

The suitability of a 3-dimensional filter in diminishing the statistical noise of left ventricular volume curves without any systematical error in the left ventricular ejection fraction (EF) was investigated. The EF values were compared in 50 studies on 24 patients. There was no significant systematical difference between the EFs before and after filtering. The filter diminishes the statistical uncertainty of the EF by a factor of 0.47. Therefore, the method may possibly be employed in processing the left ventricular volume curves.

Die Vielzahl der nuklearmedizinischen Gerate hat sich heute im Wesentlichen auf die vielseitig einsetzbare Gammakamera reduziert. Das Spektrum der Untersuchungen reicht von einfachen statischen Szintigrammen bis zu hochst komplizierten Methoden wie bei einer gegateten SPECT-Untersuchung [1]. Unerlasslich ist dabei das nuklearmedizinische Datensystem, welches nach wie vor praktisch nur zur Bilderfassung, -verarbeitung und -dokumentation herangezogen wird. Es handelt sich meistens um Single-User-Systeme eventuell mit Foreground/Background-Betrieb. Sie sind fur ihre Aufgaben, der Echzeitbilderfassung und -verarbeitung ausgelegt. Werden mehrere Gammakameras in einer Abteilung verwendet, so wird meistens ein Rechner pro Kamera eingesetzt, was oft zu einer heterogenen DV-Ausstattung fuhrt.

Timing of valve replacement (AVR) in chronic aortic regurgitation remains a difficult problem in clinical practice. When the disease takes a favorable natural course, this may be attributed to excellent compensatory mechanisms - especially an increase in left ventricular end-diastolic volume (LVEDV) in relation to regurgitant volume (RV) - whereas a rapid clinical and hemodynamic deterioration may usually be ascribed to a vicious circle consisting in a marked increase in afterload leading to an increase in LVEDV and so on. 54 patients with aortic regurgitation underwent pre- and postoperative as well as long-term follow-up radionuclide ventriculographic (RNV) studies in order to determine LVEDV and RV and to measure left ventricular ejection fraction (LVEF). These measures were expected to provide information on 'physiologic' LVEDV elevation in relation to RV. Our results indicate that if LVEDV exceeds 300-400 ml there may be an increase in afterload for LV. Factors counteracting this increased afterload (LV hypertrophy, increased diastolic stretching) will eventually preserve LVEF and keep LVEDV/RV within the normal range, but are accompanied by an elevation of LV filling pressure leading to dyspnea on exertion. With an LVEDV exceeding 400-500 ml these factors generally cannot prevent the initiation of the above mentioned vicious circle. Hence, in these severely symptomatic cases LVEDV/RV exceeds the normal range and LVEF becomes markedly depressed. An unfavorable postoperative result must be expected in these patients, while the postoperative result will be good in cases with an LVEDV/RV within the normal range. Hence, we conclude that AVR should ideally be performed in those patients with an EDV exceeding 300 ml, who still have an LVEDV/RV within the normal range, but who show clinical symptoms and/or an only moderately depressed LVEF, indicating that the limits of the compensatory mechanism are reached. The indications for AVR in other conditions characterized by the clinical status, the level of the LVEDV and LVEDV/RV are discussed.

The exact regional correlation of findings of facial bone scans, planar or SPECT, to dental orthopan X-ray films (OPT) is difficult because of the very different projection techniques. To improve correlative imaging in this regard a projection algorithm was developed that uses SPECT data of the skull for reconstructing an orthopan tomoscintigraphic projection. Fourteen conventional SPECT slices of the upper and lower jaws were obtained during bone scanning. All mandibular slices were superimposed resulting in a horseshoe shaped structure, while was marked by an ROI which was divided into segments. All 14 SPECT slices were then masked by this segmental ROI, thereby marking the teeth-carrying bone in all slices. The information from this horseshoe like ROI is then transformed into lines. Line by line arrangement results in an orthopan projection, the orthopan tomoscintigram. This new display allows 1:1 true scale superimposition with the X-ray OPT and markedly facilitates correlative imaging.

Auf dem Sektor der medikamentosen Therapie kardialer Erkrankungen gehoren zahlenmasig die Antiarrhythmika zu den haufig verordneten Arzneispezialitaten. Neben allgemeinen Nebenwirkungen auf verschiedene Organsysteme wie die Leber, den Magen-Darm-Trakt oder das zentrale Nervensystem haben antiarrhythmisch wirksame Medikamente durch ihren direkten Effekt am Herzmuskel oder am peripheren Gefassystem z. T. recht deutliche hamodynamische Auswirkungen, welche im Einzelfall nur unvollkommen untersucht und in vielen Fallen bei der antiarrhythmischen Dauerbehandlung nicht genugend beachtet werden. Die primare hamodynamische Wirkung eines Antiarrhythmikums auf das kardiovaskulare System ist aber nur eine von mehreren Determinanten eines Summationseffekts. Folgende Faktoren kommen bei diesem Summationseffekt in Frage: 1) LV-Funktion:Ausmas einer evtl. Kontraktionsstorung; 2) Auswirkung der Rhythmusstorung auf die Hamodynamik per se; 3) Effizienz autonomer Kompensationsmechanismen; 4) hamodynamisches Profil des Antiarrhythmikums: negative Inotropie, Wirkung auf den peripheren Widerstand (Vasokonstriktion/Vasodilatation), Wirkung auf die Herzfrequenz (Bradykardie), Wirkung auf den arteriellen Blutdruck (Hypotension); 5) Dosis und Applikationsart des Antiarrhythmikums.

The effect of a controlled-release formulation of isosorbide-5-mononitrate (IS-5-MN) was studied in patients with coronary heart disease (CHD), with the aim of comparing the acute effect with that after chronic administration on parameters of ischemia. To determine whether any tolerance developed, several aspects of ischemia were observed: ECG signs, clinical parameters, and left ventricular function. Fifteen patients with angiographically proven CHD were examined with 12-lead exercise ECG before, 2 h and 4 h after the first dose and after 10 days of therapy with 60 mg IS-5-MN (Coleb-Duriles) once daily. After 7 days, three radionuclide ventriculographies were performed: control, 2 h after nitrate and 2 h after 75 mg gallopamil. Plasma concentrations of IS-5-MN were measured before every exercise test. The results showed a reduction of total ST-segment depression from 0.59 mV to 0.29 mV after 2 h (NS) and 4 h (P < 0.05) on the Ist day and from 0.48 mV to 0.32 mV (P < 0.05) and 0.31 mV (NS) after 10 days. The severity of angina pectoris was diminished by about 50%. The effect on exercise duration and time to ST-segment depression by more than 0.1 mV remained unchanged after 10 days, whereas the effect on blood pressure, heart rate and time to onset of angina was attenuated. The mean decrease in ejection fraction (EF) from rest to exercise was reduced from —5.9% to — 1.9% (P < 0.05) after nitrate, while an increase of + 1.4% was seen after gallopamil (P < 0.01). Regional wall motion analysis revealed functional improvement especially in the ischemic segments of the left ventricle. Plasma concentrations of IS-5-MN were 14.7, 317 and 359 ng/ml on the first day, 94.2, 432 and 408 ng/ml after 7, and 104, 420 and 420 ng/ml after 10 days. We conclude that ST-segment depression and angina pectoris are reduced by 60 mg controlled-release IS-5-MN after the first dose and after a once-a-day therapy for 10 days to a comparable degree. Analysis of global and regional function after 7 days demonstrates an anti-ischemic effect of IS-5MN; gallopamil leads to further improvement. Plasma concentrations of IS-5-MN vary during 24 h, which prevents the development of tolerance. The plasma concentration 24 h after the last nitrate dose seems to exert a small anti-ischemic effect.

The value of the four main imaging tools: radiology, magnetic resonance imaging, echocardiography and nuclear cardiology depends in the first place on physical properties which determine the spatial, temporal and density resolution and second on the conditions under which the relevant information can be obtained with respect to the diagnostic or therapeutic problem, the comfort of the investigation, the degree of invasivity and the expenses. For several decades radiology was the only available method that allowed a look into the body. Thereby, all relevant information about diseases amenable to any surgical or conservative therapy could be attained. Parallel to the progress of cardiovascular surgery, angiocardiography could provide the anatomic and functional characteristics of congenital and acquired heart diseases. The basic principles for the measurement of total heart size, volume and shape were established already before contrast injection – initially by hand – showed the internal architecture of the heart cavities and the circulatory system. With the invention of film changers, the fundamental knowledge about all kinds of malformations of the heart and vessels was gained. Further technical progress made the procedures faster by cineangiocardiography, more comfortable by simultaneous biplane operation and easier to handle by videotechniques, allowing electronic data processing, storage and retrieval in bright operating theaters. Computer technology favored flexible image processing which, like digital subtraction and functional angiocardiography, could reduce the amount of contrast material to be injected and thereby improve the compatibility, due to better nonionic contrast material and shorter study times. Finally, computer tomography with cross sectional, or spiral data collection enabled a dynamic three-dimensional reconstruction and visualization of the beating heart and to display selected information in ‘measures and numbers’. Inspite all these successes, the ‘stain’ of invasivity remains. Strong competition arose first in echocardiography, which – after some pioneering activities in Germany in the late 1950s – flourished in the 1970s, after being reimported from the US. Most of the rapidly increasing number of ultrasound technologies – from M-mode, via various 2D linear and sector scanning procedures in combination with continuous, pulsed and/or color Doppler methods, new contrast-echo modalities and finally 3D volume scanning procedures – can be applied without any harm in all age groups and from each competent practitioner with comparably small and cheap equipment. Only oesophageal and intravascular approaches retain a touch of invasivity. Consequently not much room remains for other techniques except those, like MRI, which can differentiate tissue properties better and with higher resolution and give unlimited access to all intrathoracic organs noninvasively. Under these conditions the indications for nuclear cardiology are restricted to the small field of myocardial perfusion and metabolic studies, whereas transit time measurements and radionuclide ventriculography are practically obsolete.

The diagnosis of tricuspid regurgitation (TR) is difficult to make by simple clinical methods or by invasive techniques. Contrast echocardiography and Doppler echocardiography have improved diagnostic results, but a golden standard is still not available. Radionuclide ventriculography (RNV) is a well- established method for the detection and quantification of a volume load on the left ventricle: the regurgitation fraction can simply be derived from the regurgitant index as the ratio of enddiastolicendsystolic count-rate differences between the left and right ventricle. In left heart valvular regurgitation a regurgitant index exceeding the upper normal limit can be expected. This study was performed to evaluate the diagnostic accuracy of an abnormally low regurgitant index in detecting TR, which is accompanied by an isolated volume load on the right ventricle. A series of 33 patients with TR on physical examination and cardiac catheterization underwent RNV and was compared with 48 patients with right ventricular enlargement or pressure load on the right ventricle. In addition, the specificity of the method was evaluated in 470 consecutive patients with various forms of heart disease. In 18 out of 20 subjects with isolated TR a regurgitant index below the lower normal limit was found. The remaining 2 cases with minor TR had a regurgitant index within the normal range, which is 0.89 to 1.97 in this laboratory. In patients with additional volume load on the left ventricle, the sensitivity of the method was found to be low, as could be expected from the principle of the method. The time-activity curve over the liver was usually in phase with that recorded over the atria in subjects with TR. Therefore, the additional examination of a region of interest over the liver was particularly useful in these patients with concomitant aortic or mitral valve regurgitation. None of the 48 patients with right ventricular enlargement or pressure load on the right ventricle had a falsely positive result. A total of 17 out of 470 consecutive patients had a regurgitant index below the normal range; left ventricular function was severely impaired in 9 of these patients. The remaining subjects had a regurgitant index slightly below the lower normal limit. In conclusion, RNV has a high sensitivity in the diagnosis of TR in patients without left heart valvular regurgitation and a high specificity in patients without severely impaired left ventricular function and without left-to-right shunt through an atrial septal defect. As in patients with right ventricular volume load from an atrial septal defect, RNV appears to allow the quantification of TR. This, however, cannot be proven directly since a golden standard for quantification of TR is not available.

Equilibrium (gated) radionuclide ventriculography is based on the fact that the heart is a periodically contracting organ. The amount of radioactivity in the heart is proportional to the amount of blood in its cavities, provided there is homogeneous distribution in the blood pool. Thus, the precordial count rate changes reflect the cyclic volume changes of the heart. Because the precordial count rate is too low for a reliable determination of a beat-by-beat time-volume curve, Hoffmann and Kleine applied a gating procedure, using the R-wave of the electrocardiograph (ECG) and a multichannel analyzer [24] to synchronize and sum hundreds of heart cycles. This resulted in a representative cardiac cycle and a well-delineated time activity curve, which is analogous to a time-volume curve. Since the left and right ventricles could not be differentiated by this technique, and an additional x-ray investigation was required for their delineation, Adam et al. [1, 4] and Bitter et al. [9] applied the gating procedure to a camera computer system. Representative time-activity (time-volume) curves of the left and right ventricle were obtained using an electronic cursor to isolate the ventricles.

Bei 62 Patienten mit Verdacht auf eine koronare Herzerkrankung wurden Radionuklid-Ventrikulographie und Kontrast-Ventrikulographie durchgeführt. Die unabhängige Auswertung beider Untersuchungen ergab eine hohe Übereinstimmung bei lokalen Wandbewegungsstörungen. Lediglich 2 Fälle entgingen der szintigraphischen Entdeckung bei angiographisch nachgewiesener Bewegungsstörung der Hinterwand. Die Sensitivität der Radionuklid-Ventrikulographie betrug 97%, die Spezifität 80%. Bei 4 Patienten, die angiographisch unauffällig waren, ließ sich szintigraphisch ein eindeutig negativer Befund nicht erheben (2 x Koronarinsuffizienz, 1 Mitralinsuffizienz und 1 hypertrophische Cardiomyopathie). An 70 Patienten mit klinisch gesichertem Herzinfarkt zeigte die Radionuklid-Ventrikulographie eine hohe Sensitivität (97%), während eine Perfusionsstörung mit Thallium nur in 66% nachgewiesen werden konnte (nicht mehr frische Infarkte).

Die mit Hilfe der Radionuklid-Ventrikulographie bestimmten Auswurfsfraktionen wurden mit Ergebnissen verglichen, die nach folgenden konventionellen Methoden erzielt wurden:1) Biplane Cineangiographie mit der Simpson-Regel. Dabei ergab sich eine Korrelation von r = 0,805 (n = 25).2) Der Vergleich mit der Flächenlängenmethode bei den gleichen Patienten ergab eine Korrelation von r = 0,88 (n = 25).3) Nach der monoplanen Cineangiographie und Anwendung der Methode nach Greene et al. (5) ergab sich eine Korrelation von r = 0,86 (n = 35).Die aus der Zeit-Aktivitätskurve ermittelte maximale Kontraktionsgeschwindigkeit wurde mit der mittleren systolischen Austreibungsrate, die bei der Cineangiographie erzielt wurde, verglichen. Dabei ergab sich eine geringe Korrelation (r = 0,62, n = 20). Dabei muß berücksichtigt werden, daß die nuklearmedizinische Methode die maximale Kontraktionsgeschwindigkeit, die cineangiographische Methode aber einen Mittelwert über die gesamte Systole bestimmt.

Natrium-Aluminium-Silikate werden in amorpher und kristalliner Form seit vielen Jahren in verschiedenen technischen Prozessen eingesetzt. Die kristallinen Natrium-Aluminium-Silikate, Zeolithe, gehoren zur Gruppe der Gerustsilikate und sind schon lange durch ihre reversibel wasseraufnehmenden und erdalkaliaustauschenden Eigenschaften bekannt. In letzter Zeit haben Natrium-Aluminium-Silikate besondere Beachtung gefunden, weil die Kationaustauschaktivitat in Waschmitteln zur Herabsetzung der den Waschprozes storenden Wasserharte ausgenutzt werden kann. Damit ist die Moglichkeit des Ersatzes der Polyphosphate der Waschmittel gegeben. Zeolithe konnen als Pulver oder als Aufschlammung der Waschmittelindustrie zur Verfugung gestellt werden. Die Pulverherstellung durch Spruhtrocknen wirft keine besonderen Probleme auf; die Einarbeitung der Pulver in den Waschmittelslurry scheint vom Standpunkt der Energieeinsparung ein Anachronismus zu sein. Die Optimierungsarbeiten fur Zeolithaufschlammungen ergaben stabile Produkte mit 45 bis 48% Zeolithgehalt. Dabei wurde die Theorie der kritischen Teilchenkonzentration angewandt. Sodium Aluminium Silicates - Properties and Application Sodium aluminium silicates in amorphous and crystalline form are used since many years in various technical processes. The crystalline sodium aluminium silicates, e. g. zeolites, belong to the group of structured silicates and are known for their reversible water uptake and alkaline earth exchange properties. Recently, sodium aluminium silicates have gained considerable importance since their cation exchanging ability can be utilized in washing agents for the removal of undesirable hardness of water. Thus, the polyphosphates used in washing agents can possibly be substituted. Zeolites can be supplied to the detergent industry in the form of powder or suspension. Production of the powder by spray drying does not involve special problems. Incorporation of the powder into the slurry of the detergent appears to be an anachronism from the viewpoint of energy saving. Optimization work on suspensions of zeolite yielded stable products with 45 to 48% zeolite content. The theory of critical particle concentration was applied in this work.

Beim Radiojodtest werden nach Applikation von diagnostischen Dosen von Radiojod radioaktive Schilddrüsenhormone gebildet und sezerniert (endogene Markierung). Hier wird eine Methode demonstriert, mit der die Schilddrüsenhormone aus dem Serum säulenchromatographisch isoliert und die inkorporierten Zählraten im Zeitverlauf erfaßt werden können. Die Erfassung der niedrigen Zählraten wird durch die Messung mit einer Low-Level-Zählapparatur erreicht. Die Methode erlaubt eine verbesserte Erfassung der Hormonphase beim Radiojodtest. Die vorliegenden Ergebnisse zeigen eine gute diagnostische Diskriminierung zwischen Euthyreose, grenzwertiger und ausgeprägter Hyperthyreose (Faktor 10 bzw. 40). Beeinflussende Faktoren wie kleiner intrathyreoidaler Jodpool müssen natürlich berücksichtigt werden. Unter Einbeziehung weiterer Größen wie intrathyreoidaler Jodpool, Hormonclearance etc. ließe sich ein Modell zur Messung der Sekretion der Schilddrüsenhormone aufbauen.

By "camera-cinematography" of the heart, we mean an isotope method which permits detailed observation of cardiac mechanics without the use of a catheter. All that is necessary is an intravenous injection of 10 to 15 mCi 99mTc human serum albumen followed after ten minutes by a five to ten minute period of observation with a scintilation camera. At this time the isotope has become distributed in the blood. Variations in the precordial impulses correspond with intra-cardiac changes of blood volume during a cardiac cycle. Analysis of the R-wave provides adequate information of cyclical volume changes in limited portions of the heart. This is achieved by a monitor with a pseudo-3-dimensional display; contraction and relaxation of the myocardium can be shown for any chosen longitudinal or horizontal diameter of the heart. Our programme allows simultaneous presentation of the movement of any point on the myocardium as a time-activity curve. The method is recommended as an addition to chest radiography, heart screening or cardiac kymography before carrying out cardiac catheterisation.

Although the antianginal properties of molsidomine are well-established, little is known about its effects on global and regional left ventricular dysfunction secondary to myocardial ischemia. In the present study, left ventricular performance was assessed by radionuclide ventriculography at rest and during exercise in 15 patients with coronary artery disease (CAD) and angina pectoris before and after the administration of 2 mg molsidomine sublingually. Gated blood pool studies were performed for evaluation of left ventricular ejection fraction (LVEF) and regional wall motion by analyzing amplitudes and phases of the first Fourier coefficient of regional time–activity curves. In contrast to normal subjects, during the control study period LVEF in patients with CAD decreased from 50.9% at rest to 42.7% during exercise (p 0.10). In conclusion, assessment of left ventricular performance at rest and during exercise in patients with CAD revealed significant improvement of global and regional left ventricular function, indicating reduction of myocardial ischemia. These effects may result primarily from reduction of left ventricular wall tension.

Etwa 5% der Bevolkerung der Bundesrepublik Deutschland leben im Einzugsbereich von Seen, die durch schnell voranschreitende Eutrophierungsvorgange bedroht sind. Ein Ersatz der Wachmittelphosphate durch andere Calcium-bindende Produkte wurde dieses Problem nicht losen. Eine 90%ige Elimination der Abwasserphosphate in dritten Klarstufen verspricht eine schnelle Verbesserung der Wasserqualitat, wie die Erfolge in Schweden und der Schweiz zeigen. In den Einzugsbereichen der drei durch Staustufen auch im Sommer schiffbar gemachten Flusse Mosel, Main und Neckar leben ca. 17% der Bevolkerung der Bundesrepublik Deutschland. In den Sommermonaten ergeben sich schwere okologische Probleme durch Algenbluten in den Stauraumen. Infolge des sehr ungunstigen Umgebungsarealfaktors kann selbst mit klartechnischen Masnahmen einschlieslich Phosphatfallung nur ein begrenzter Erfolg erwartet werden. Washing Agents and Water Safety About 5% of the population in Federal Republic of Germany live in the region of lakes, that are in danger of becoming eutrophic. Substituting the phosphates used in washing agents by other calcium-binding products would not solve this problem. Successes made in Sweden and Switzerland have shown that 90% of the phosphates in waste water can be removed in a third step of clarification, which rapidly improves the quality of water. Around 17% of the population live in the region of rivers Mosel, Main and Neckar. Difficult ecological problems arise in the summer months due to growth of algae in the dam area. In such regions measures for clarification, including precipitation of phosphates is of limited success, owing to difficult environmental conditions.

The present investigation was undertaken to introduce a quantitative scintigraphic method for evaluation of regurgitation and to compare it with the generally accepted quantitative method of Sandler and Dodge (Sandler et al., 1963). Radionuclide ventriculography was carried out after injection of 20 mCi 99mtechnetium-labeled red blood cells. Time-activity curves were obtained from the left and right ventricular regions. The ratio (A) of end-diastolic-end-systolic count-rate differences for the left and right ventricles was calculated. The ratio (A) was compared with a hemodynamic ratio (Ah) determined after the method of Sandler and Dodge (1963) with the stroke volume of the left ventricle measured angiographically, and the stroke volume of the right ventricle measured by thermodilution. In 33 patients with aortic and mitral valve regurgitation we found a correlation of r = 0.75 between (A) and Ah). Due to a broad range of normal values of (A) the sensitivity of the scintigraphic method is low. The specificity seems to be high, however, since in 64 patients with all types of heart diseases there were no false positive results. Comparing the described scintigraphic method with other modern or generally accepted methods, the principal advantages are noninvasiveness, good practicability, and the fact that important additional information about the functional state of the heart is gained. This is important in follow-up studies in patients with chronic valvular incompetence. It seems that this method will become a valuable supplement to heart catheterization in the diagnosis of valvular heart disease and may partially replace invasive methods for measuring the regurgitation fraction.

The effect of hypothyroidism on left ventricular function at rest and during exercise was studied in nine patients without demonstrable cardiovascular disease who had had total thyroidectomy and ablative radioiodine treatment for thyroid cancer. Radionuclide ventriculography and simultaneous right heart catheterisation were performed while the patients were hypothyroid two weeks after stopping triiodothyronine treatment (to permit routine screening for metastases) and while they were euthyroid on thyroxine replacement treatment. When the patients were hypothyroid, cardiac output, stroke volume, and end diastolic volume at rest were all lower and peripheral resistance was higher than when they were euthyroid. Pulmonary capillary wedge pressure, right atrial pressure, heart rate, left ventricular ejection fraction, and the systolic pressure:volume relation of the left ventricle, which was used as an estimate of the contractile state, were not significantly different when the patients were hypothyroid or euthyroid. During exercise, heart rate, cardiac output, end diastolic volume, and stroke volume were higher when the patients were euthyroid than when they were hypothyroid. Again, pulmonary capillary wedge pressure, ejection fraction, and the systolic pressure:volume relation were similar in both thyroid states. The data suggest that the alterations in cardiac performance seen in short term hypothyroidism are primarily related to changes in loading conditions and exercise heart rate; they do not suggest that acute thyroid hormone deficiency has a major effect on the contractile properties of the myocardium.

Aniontenside vom Typ Alkylethersulfate und Alkylsulfate werden in grosem Umfang in der reinigenden Kosmetik eingesetzt. Ziel der Untersuchung war es, bei gleicher molarer Konzentration der eingesetzten Tenside, die physiko-chemischen und anwendungstechnischen Eigenschaften mit den biologischen Reizwerten zu vergleichen. Zu diesem Zweck wurden die hydrophoben und hydrophilen Gruppen der Tenside variiert. Ebenso wurde bei gleichbleibendem Anion der Einflus verschiedener Kationen untersucht. Obwohl die Variation im Molekul zu teilweise sehr deutlichen Anderungen der Grenzflacheneigenschaften fuhrte, konnten keine entsprechend signifikanten Unterschiede im Tierversuch gefunden werden. Constitution and Properties of Detergents Anionic surfactants of the type alkylether sulfate and alkyl sulfate are widely used in cleansing cosmetic agents. Purpose of this study was to compare the physico chemical and practical properties with the biological irritation values at the same molar concentration of the surfactants tested. For this purpose, the hydrophobic and hydrophilic groups of the surfactants were varied. Simularly, keeping the anion constant the influence of various cations was studied. Although variation of the molecule distinctly altered the surface active properties in some cases, corresponding significant differences were not found in animal experiments.

The validity of noninvasive (iodine-131 iodohippurate renogram, iodine-131 ortho-iodohippurate clearance, indium-113m EDTA--technetium-99m DTPA sequential renal scan) and invasive (xenon-133 washout) radionuclide screening tests was evaluated in the diagnosis of 105 patients with unilateral renovascular hypertension (RVH) and in 45 patients with essential hypertension (EH). In RVH positive findings on the stenosed side were noted in 73% of renograms, 73% of o-iodohippurate-clearance tests (N = 22), 81% of sequential renal scans, and 90% of xenon-washout studies (N = 67). In a subgroup of 55 retrospectively selected patients with normal or improved blood pressure following renovascular surgery, the preoperative findings had been positive on the stenosed side in 78% of renograms, 75% of o-iodohippurate-clearance tests (n = 20), 85% of sequential renal scans, and 93% of xenon-washout studies (n = 23). The sequential renal scan appears to be a sufficiently reliable method in noninvasive screening for unilateral RVH, although invasive xenon-washout studies show a higher percentage of hemodynamic alterations in the stenosed kidney. o-iodohippurate clearance tests, and in particular xenon-washout studies, can reveal arteriosclerotic lesions in the contralateral, non-stenosed kidney, which may be of importance when the decision for renovascular surgery is pending.

Alkylethersulfate auf Basis von Fettalkoholen haben ihren festen Platz in modernen Badepraparaten und flussigen Reinigungsmitteln. Der jahrliche Verbrauch in der Bundesrepublik Deutschland liegt bei ca. 20000 t. Die Variationsmoglichkeit von Kettenlange des Alkyls und Ethoxylierungsgrad ermoglicht eine optimale Anpassung der Ethersulfate an den Einsatzzweck. Alkylethersulfate sind toxikologisch unbedenklich und biologisch gut abbaubar. Als Hilfe bei der Formulierung von Fertigprodukten wird die Erstellung einer ISO-Visko-Kurve vorgeschlagen; hierbei ist bei gegebener Viskositat die notige Kochsalzmenge eine Funktion der Ethersulfat-Konzentration. 70%ige Ethersulfate, ohne Zusatz von verflussigend wirkenden Substanzen, werden in zunehmender Menge eingesetzt. Ihre Verarbeitung wird besprochen.

The present investigation was undertaken to assess a new scintigraphic method for the diagnosis of left-to-right shunts due to atrial septal defect based on the differing stroke volumes of left and right ventricles and to compare it with oxymetric data. Radionuclide ventriculography was carried out after injection of 20 mCi /sup 99m/Tc-labeled red blood cells. Time-activity curves were obtained from the left and right ventricular regions, and the ratio (A) of end-diastolic-end-systolic count rate differences for the left and right ventricles was calculated. The left-to-right shunt (in percent of the pulmonary flow rate) is then given as 100 X (1 - A/1.43; 1.43 being the previously determined mean value of A in 66 normal patients. In 16 patients with an atrial septal defect and/or partial anomalous pulmonary venous connection a correlation of r . 0.81 was found between those shunts determined by the scintigraphic method and those calculated by oxymetric data. The specificity of the method and the sensitivity in detecting left-to-right shunts exceeding 30% are high. The method is practical and already widely used for determination of ejection fraction end-diastolic volume and other factors. The combination of this technique with other methods for shunt diagnosis such as gamma-fit analysismore » may prove of special value.« less

Ausgehend von den lokalen Zeit-Aktivitäts-Kurven werden Parameter berechnet, welche die regionale Wandbewegung der Herzkammern beschreiben und die es gestatten, sowohl die Grenzen der Herzkammern festzulegen als auch segmentale Wandbewegungsstörungen zu erfassen. Als globaler Funktionsparameter wird die Austreibungsfraktion des linken Ventrikels aus den enddiastolischen und endsystolischen Zählraten berechnet. Die Untergrundstrahlung wird mit Hilfe eine Methode abgeschätzt, welche die Untergrund-Inhomogenität berücksichtigt.

Die rechnergestützte szintigraphische Funktionsanalyse des Herzmuskels gestattet nicht nur, globale Volumenparameter (Austreibungsfraktion, endsystolische und enddiastolische Volumina, Kontraktions- und Relaxationsgeschwindigkeiten) zu erfassen, sondern beschreibt auch Störungen der Regionalfunktion qualitativ und quantitativ durch die Parameter Phase und Amplitude, die beide aus den regionalen Zeit-Aktivitätskurven durch Fourieranalyse gewonnen werden können. Das Ruhe-Herzfunktions-Szintigramm eignet sich daher zur Erkennung von infarktbedingten Asyner-gien bzw. zur Verlaufskontrolle nach akutem Myokardinfarkt. Da Mehrfachuntersuchungen innerhalb der ersten Stunden nach einer Radionuklidapplikation problemlos durchgeführt werden können, bietet sich das Radionuklidventrikulo-gramm darüber hinaus besonders zur Darstellung der Wirkung von Medikamenten an (Interventions-Radionuklidventri-kulographie), was unter anderem eine Unterscheidung reversibler und irreversibler Bewegungsstörungen ermöglichen kann. Unter Ergometerbelastung neu aufgetretene Bewegungsstörungen im Belastungs-Herzfunktions-Szintigramm weisen auf eine hämodynamisch relevante Koronarstenose hin.

It was the purpose of this study to evaluate the diagnostic usefulness of an oral absorption test using nonlabeled Vit B12 suggested by a commercial distributor as an alternative for the more expensive Schilling test (ST). Plasma levels of Vit B12 were measured with a commercial kit before and 4 h after oral administration of 1 mg Vit B12 in 32 normals, in 16 patients with normal ST, and in 14 patients with abnormal ST for determination of sensitivity and specificity with the ST as golden standard. In normals, a mean of 767 +/- 404 pg/ml before and 1096 +/- 776 pg/ml after oral Vit B12 with a mean increase of 331 +/- 453 pg/ml was measured. Because of the obvious large variation, no meaningful range for normal absorption could be established. In the two patient subsets, there was no Gaussian distribution of the results, with a meridian of Vit B12 increase after absorption of 142 pg/ml, range 27-2668 pg/ml, in the group with normal ST and a meridian of 244 pg/ml ranging from 40 to 2453 pg/ml in the group with abnormal ST. Statistical nonparametric analysis did not reveal any difference between the two groups. Assuming a minimum required increase of 100 pg/ml, as suggested by the kit distributor, a sensitivity of only 27% and a specificity of 75% was obtained.(ABSTRACT TRUNCATED AT 250 WORDS)

ZusammenfassungEs werden zwei Verfahren zur digitalen und analogen Auswertung von Aufnahmen mit der Szintillationskamera nach Anger beschrieben. Wesentlicher Bestandteil beider Auswerteeinheiten ist ein Magnetbandgerät, das die Kameraimpulse während der szintigraphischen Messung analog aufzeichnet. Diesem Zwischenspeicher können die Kameraimpulse beliebig oft und unter wechselnden Auswertebedingungen entnommen werden, so daß detaillierte quantitative Funktionsuntersuchungen mit der Szintillationskamera möglich sind.Beim ersten und elektronisch wenig aufwendigen Verfahren werden die Lichtpunkte der Szintillationskamera mit Hilfe eines Photomultipliers in Spannungsimpulse verwandelt, die entweder digital oder analog registriert werden können. Kernstück des zweiten Auswerteverfahrens bildet ein Digitalcomputer, der einerseits mit Hilfe von Analog-Digital-Konvertern die analogen Kameraaufnahmen in einer Digitalmatrix speichert und andererseits die mathematische Analyse der Kameraszintigramme ermöglicht. Von großem Wert für die Auswertung der Kameraszintigramme sind auch die vielfältigen Ausgabeeinrichtungen des Elektronenrechners.

Es wird in Anlehnung anBianchi undToni uber eine Clearance-Methode berichtet, die auf externenen Harnblasenaktivitatsmessungen beruht und den Harnblasenkatheter uberflussig macht. Bei dieser Modifikation des Verfahrens dient die Tracer-Substanz lediglich der Bestimmung der Dauer der Clearance-Periode. Die nierengangige inaktive Testsubstanz in den Serum- und Urinproben wird chemisch bestimmt. Dadurch entfallen die sich aus der Jodabspaltung ergebenden Probleme. Damit sind auch simultane PAH-Inulin-Clearance-Untersuchungen moglich. Vergleichende Bestimmungen des Glomerulumfiltrates an 17 Patienten ergaben eine statistisch gesicherte Ubereinstimmung mit der konventionellen Inulin-Clearance (Mittelwert der Differenzen=1,8 ml/min).

Simultane Clearance-Untersuchungen mit J131H und PAH wurden an 11 nierengesunden Versuchspersonen und 5 Patienten mit Nierenerkrankungen durchgefuhrt, um die Brauchbarkeit der oJ131H zur Bestimmung der renalen Plasmadurchstromung zu uberprufen. In allen Fallen waren die Ergebnisse der oJ131H-Clearance bei der Anwendung der klassischen Infusionstechnik signifikant niedriger als die der PAH-Clearance, im Mittel 128,0 ml/min. Zur Erklarung dieser Differenz reicht der papierchromatographisch nachweisbare freie J131H-Anteil der oJ131H-Clearance nicht aus. Mogliche Ursachen werden diskutiert. Die oJ131H-Clearance kann die PAH-Clearance noch nicht voll ersetzen.

Waschmittel mit Enzymzusatzen sind seit 1966 in groserem Umfange auf dem deutschen Markt erschienen. Heute entfallt in der ganzen westlichen Welt ein wesentlicher Teil (etwa 80%) des Waschmittelverbrauchs auf diesen Waschmitteltyp. Im Rahmen der vorliegenden Arbeit wird die gesundheitliche Unschadlichkeit enzymhaltiger Waschmittel an Hand von Versuchsergebnissen nachgewiesen. Es werden Testmethoden und Ergebnisse uber die Toxizitat und Reizwirkung dieser Waschmittel bei cutaner Applikation sowie von Hautsensibilisierungsstudien geschildert. Scientific Investigations on the Tolerance of Enzyme-Containing Washing Agents Washing agents containing enzyme-additives appeared in the German market since 1966 on a wide scale. Today, in the entire western world, this type of detergent constitutes a considerable proportion (80%) of the total consumption of washing agents. In the present work based on experimental results, it is proved that enzyme-containing washing agents are not harmful to health. Test-procedures and results on the toxicity and irritation for these washing agents are reported for cutaneous application, and studies on skin-sensibilisation are described.