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Biomedical subjects

H Bergmann

Publications and source records attributed to H Bergmann.

At least 109 records · Page 6Linked to original sources
PubMed1988

The World Health Organization and International Atomic Energy Agency second interlaboratory comparison study in 16 countries on quality performance of nuclear medicine imaging devices.

Sixteen European countries participated in this WHO-IAEA intercomparison for which transmission CAP (College of American Pathologists) thyroid and IAEA-WHO liver phantoms were used. A total of 257 laboratories submitted 428 image evaluation reports. Overall results showed differences in performance between the various countries but similarities in performance for two gamma camera subgroups defined by year of manufacture, before and after 1980. A unique review of current European liver imaging practice is presented in terms of technical parameters, imaging conditions and evaluation procedures, and quality control procedures. The WHO-IAEA intercomparison demonstrated the need to establish new, or to improve the existing, quality control programmes in certain countries. However, the large number of participating laboratories, 257 compared with 70 in the previous WHO study, (Volodin et al. 1985), shows that these international studies are serving a useful purpose in promoting quality control in nuclear medicine imaging laboratories.

Europe↗
PubMed1988

Right ventricular performance and pulmonary haemodynamics in adolescent and adult patients with cystic fibrosis.

A combined haemodynamic and radionuclide approach was used to evaluate right ventricular performance in 16 adolescent and adult patients with cystic fibrosis (CF). There were nine patients with mild arterial hypoxaemia (PaO2 greater than 80% of predicted) and normal resting pulmonary artery pressure and seven patients with severe arterial hypoxaemia (PaO2 less than 70% of predicted) and resting pulmonary arterial hypertension (PH). The right ventricular ejection fraction (RVEF) by equilibrium angiocardiography using krypton 81m as a tracer and stroke volume index (SVI) by thermodilution techniques were measured simultaneously and right ventricular end-diastolic and end-systolic volumes were derived. RVEF was normal in CF patients without PH (58.9 +/- 7.2%) but was reduced in those with PH (45.4 +/- 2.6%). There was a statistically significant inverse linear correlation between RVEF and afterload as assessed by mean pulmonary artery pressure (Pap: r = -0.76) and pulmonary vascular resistance (PVR: r = -0.78), indicating that RVEF ist afterload-dependent. Right ventricular function, however, as assessed by right ventricular end-systolic pressure-volume relations was even higher in CF patients with PH, indicating preserved or even increased right ventricular function in the face of an increased afterload stress.

Adolescent↗
PubMed1988

Right-ventricular contractility in chronic obstructive pulmonary disease: a combined radionuclide and hemodynamic study.

The effect of pulmonary artery hypertension on right-ventricular performance in patients with chronic obstructive pulmonary disease (COPD) is unclear. Decreased values of right-ventricular ejection fraction (RVEF) have been reported, but most patients with stable COPD are not in cardiac failure and have normal or even increased cardiac outputs. We therefore hypothesized that RVEF may be afterload dependent, and thus a poor parameter of cardiac function, and that right-ventricular contractility may be normal even in COPD patients with pulmonary hypertension. We therefore studied 24 COPD patients using a combined hemodynamic and radionuclide approach. RVEF and thermodilution stroke volume index were measured simultaneously at rest in all 24 patients and also during bicycle ergometry in 9 patients. We then calculated end-diastolic and end-systolic volume indices and derived right-ventricular systolic pressure-volume relations in all and the slopes (E) of the pressure-volume line in 9 patients. RVEF was normal in COPD patients without pulmonary hypertension, but was reduced in those with pulmonary hypertension. A strong inverse linear relation between RVEF and mean pulmonary artery pressure (r = -0.73; p less than 0.001) and pulmonary vascular resistance (r = -0.69; p less than 0.001) could be demonstrated, indicating RVEF to be highly afterload dependent. Right-ventricular end-diastolic volume index was significantly higher in patients with pulmonary hypertension, indicating increased preload as the major mechanism to maintain adequate stroke volume in the face of an increased afterload. Right-ventricular end-systolic pressure-volume relations, a good parameter to define right-ventricular contractility independent of systolic loading conditions, were not different between COPD patients with or without pulmonary hypertension, nor did the slopes of the pressure-volume lines in the 9 patients studied during exercise show any difference. From these data we conclude that (a) RVEF is a poor indicator of overall right-ventricular function; (b) right-ventricular contractility is well preserved in stable COPD patients; (c) the major mechanism of maintaining stroke volume in the face of increased right-ventricular afterload seems to be preload augmentation.

Blood Pressure↗
PubMed1987

Intravenous cisapride accelerates delayed gastric emptying and increases antral contraction amplitude in patients with primary anorexia nervosa.

Delayed gastric emptying is common in primary anorexia nervosa. We investigated in 12 patients whether gastric emptying could be accelerated by the prokinetic drug cisapride. Patients were studied on two occasions 1 wk apart and received, under random double-blind conditions, 8 mg of cisapride and placebo intravenously. Gastric emptying of an isotopically labeled semisolid meal and antral motor activity were measured using a dual-headed gamma-camera for 50 min. Emptying was significantly slower (half-emptying time, 50-191 min; median, 121 min) than in 24 healthy volunteers (half-emptying times, 21-119 min; median, 47 min). Cisapride accelerated emptying significantly (p less than 0.001; half-emptying time after cisapride, 22-80 min; median, 42 min). Antral contraction amplitude increased and contraction frequency decreased significantly (p less than 0.001), whereas the propagation velocity of contractions remained unchanged. We concluded that intravenous cisapride accelerates gastric emptying and increases antral contraction amplitude in patients with anorexia nervosa. Whether or not these effects can prove beneficial in diminishing the patients' symptoms and in helping them to gain weight can only be answered from studies involving long-term treatment with cisapride.

Adolescent↗
PubMed1986

Imaging of human atherosclerotic lesions using 123I-low-density lipoprotein.

In patients suffering from clinically manifest atherosclerosis autologous LDL-labelling has been done using 123I. This technique allows localization of areas with an increased LDL entry as well as a monitoring of kinetics. Normally, no tracer uptake can be seen in the vascular system. Positive camera images, however, can be obtained in pathological areas as early as 60 min after LDL-reinjection. Experimental data and morphological control reveal a very good correlation to the gamma-camera findings. The technique seems to be very promising for diagnosis in patients suffering from atherosclerosis and hyperlipoproteinemia.

Aged↗
PubMed1986

Specific modulation of sodium channels in mammalian nerve by monoclonal antibodies.

Monoclonal antibodies (mAbs) were generated against the sodium channels in the intact membrane of the eel electroplax. These antibodies bind to nodes of Ranvier, as indicated by immunofluorescence. When externally applied to rat nerve fibers one of these mAbs blocks impulse conduction. In voltage-clamp experiments, this mAb was found to attenuate sodium current amplitude without affecting the time course. The dose-response curve was very steep and had an ED50 of 133 nM. About half of the mAb effect was shown to be due to a shift, in the hyperpolarizing direction, of the steady-state sodium inactivation versus membrane potential curve. The remaining effect was voltage- and time-independent. This mAb had no effect on the potassium or leakage currents. The results indicate that on the external surface of the sodium channel, there are a number of antigenically similar determinants, which are functionally linked to specific elements of the sodium conductance system. These functionally related determinants were preserved through the course of evolution.

Action Potentials↗
PubMed1986

Oesophageal and gastric motility disorders in patients categorised as having primary anorexia nervosa.

UNLABELLED: Gastrointestinal motor function in patients with primary anorexia nervosa has rarely been investigated. We studied oesophageal motor activity in 30 consecutive patients meeting standard diagnostic criteria for primary anorexia nervosa (Feighner et al; DSM III). Seven were found to suffer from achalasia instead of primary anorexia nervosa, one from diffuse oesophageal spasm and one from severe gastro-oesophageal reflux and upper oesophageal sphincter hypertonicity, while partly non-propulsive and repetitive high amplitude, long duration contractions prevailed in the lower oesophagus of another six. In four patients with oesophageal dysmotility not responding to therapy and in 12 of 15 patients with normal oesophageal manometry, gastric emptying of a semisolid meal was studied. Emptying was normal in only three but markedly delayed in 13 cases (half emptying times 97-330 min, median: 147 min, as compared with 21-119 min, median: 47 min, in 24 healthy controls). In eight patients, the effects of domperidone 10 mg iv and placebo were compared under random double blind conditions. Half emptying times were shortened significantly (p less than 0.01) by domperidone. CONCLUSIONS: symptoms of disordered upper gastrointestinal motor activity may be mistaken as indicating primary anorexia nervosa; clinical evaluation of patients with presumed primary anorexia nervosa should rule out the possibility that disordered oesophageal motor activity underlies the symptoms; delayed gastric emptying is a frequent feature in primary anorexia nervosa and might be returned to normal with domperidone.

Adolescent↗
PubMed1986

[Present-day and future anesthesia equipment from the viewpoint of the clinician].

With mainly clinical needs in mind, the technical and functional details of current anaesthesia equipment are discussed, as well as potential future developments. The following topics are discussed in detail: delivery of narcotic gases, dosimetry of both gaseous and volatile anaesthetics, the patterns of anaesthesia systems, mechanical ventilation during anaesthesia and intra-operative monitoring. As for the narcotic gases, plain air might become more important than ever before. The importance of helium has so far not been clearly assessed. The safety measures of the German Industry Norm (DIN) 13252 should become more widely known and be fully accepted: colour codes, non-interchangeable dimensions, oxygen bypass and oxygen-failure alarms, and automatic cut-off and alarm if the concentrations of nitrous oxide are too high. The delivery of a hypoxic gas mixture should be detectable whatever the cause might be and not only in cases when the oxygen-supply pressure is too low. Special attention should be given to the interactions between man and machines to exlude difficulties arising from "inhuman engineering". Concerning the rotameters, uniform serial attachment of these controllers of gaseous flow should be aimed at. The ranges (low flow, high flow), accuracy of the meter (+/- 3%) and DIN safety measures (different shape of button switches, etc.) should be kept in mind; a gas proportioning and mixing device that would strictly exclude the possibility of too-low oxygen concentrations would be very advantageous. The vaporizers for volatile anaesthetics should work independently of external physical variables and also fulfil the DIN safety programme.(ABSTRACT TRUNCATED AT 250 WORDS)

Anesthesia, Inhalation↗
PubMed1986

[Diagnosis of radionuclide uptake using a whole body counter].

Measurements of whole body radioactivity are performed at our department using a shadow shield whole body counter with automated gammaspectrum analysis. After the radioactive fall-out in Austria due to the reactor accident in Chernobyl the instrument has mainly been used for the assessment of the radiation level in the general population. Amongst the radionuclides incorporated 131-I and 137-Cs had the highest activities. The results of our measurements are summarized in two graphs. At present an increase of 137-Cs activity in the population is clearly observed.

Accidents↗