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Biomedical subjects

P Held

Publications and source records attributed to P Held.

At least 127 records · Page 7Linked to original sources
PubMed1989

[The value of MR tomography in tumorous diseases of the inner nose and paranasal sinuses].

In the examination of the inner nose and the paranasal sinuses, magnetic resonance imaging impresses by its excellent representation of anatomical structures, due above all to the multiplanar orientation of slices, the good possibility to differentiate soft tissue structures, and the accurate visualization of lymph nodes and vessels without contrast medium. Osseous lesions can be better assessed by computed tomography, however, magnetic resonance imaging can indirectly demonstrate bone destructions, too.

Adenocarcinoma↗
PubMed1989

[Diagnostic possibilities of magnetic resonance tomography (MRT) in the retroperitoneal space].

The diagnostic value of MR-imaging is tested on 130 patients with pathological retroperitoneal processes. Improved imaging techniques resulted in a more accurate delineation of tumor extension than seen with CT-imaging. Using a ratio of signal intensity from the adrenal tumors and the liver on T2-weighted images, it is usually possible to differentiate adenomas from metastases, carcinomas or phaeochromocytomas. New indications for renal MR-imaging would be parenchymal renal disease and transplant rejections. Moreover, MR allows visualization of lumbar lymph node-chains in the coronal view corresponding to the situs during surgery, thus, facilitating preoperative orientation for the surgeon.

Diagnosis, Differential↗
PubMed1988

Fluorometric analysis of DNA in cell cultures.

A simple, reproducible fluorescent assay has been described which can be used confidently at microgram and submicrogram levels. The method is most suitable for cell cycle and cell growth analysis using [3H]thymidine as the radioactive tracer. A modified method is also described for preparing diaminobenzoic acid hydrochloride.

Aminobenzoates↗
PubMed1987

Central haemodynamic and antiplatelet effects of iloprost--a new prostacyclin analogue--in acute myocardial infarction in man.

In 14 patients with acute myocardial infarction, a 24-hour Iloprost infusion was started with a mean delay of 309 +/- 22 minutes from onset of symptoms. Patients were haemodynamically monitored with a pulmonary artery catheter and an arterial cannula. The dose of Iloprost was 1-4 ng kg-1 min-1 and titrated according to blood pressure and systemic vascular resistance. When 2.0-4.0 ng kg-1 min-1 of Iloprost were infused, 5 out of 10 patients required dose reduction due to hypotension, nausea or both. However, in all patients the infusion period was completed as planned. Acute reductions of systolic blood pressure and vascular resistance were seen, whereas stroke volume increased and heart rate remained unchanged. The infusion of Iloprost caused profound inhibition of ADP-induced platelet aggregation but no significant changes in plasma values for platelet-specific proteins or thromboxane B2 were recorded. It is concluded that it was possible to safely administer Iloprost over 24 hours in the early phase of acute myocardial infarction and profound anti-aggregatory effects were observed. These findings should be evaluated in a controlled study.

Adult↗
PubMed1987

Haemodynamic effects of felodipine in congestive heart failure.

The acute and long term central haemodynamic effects of felodipine were studied in 9 patients with severe congestive heart failure (NYHA III-IV). A felodipine dose of 5 to 15 mg tid was individually titrated during a 24 to 48 hour catheterisation period. One patient received 5mg tid, 5 patients 10mg tid and 3 patients 15 mg tid. At rest the individual maximal dose was associated with a significant fall in systolic and diastolic blood pressure, pulmonary artery diastolic pressure, heart rate and systemic vascular resistance, while stroke volume was significantly increased. During upright submaximal (30-50 watts) bicycle exercise, the changes were principally the same with the addition of a significant increase of cardiac index. Six patients were re-evaluated after 30 days of continuous treatment. Their resting haemodynamics had returned to the control level but during exercise the significant changes in cardiac index, stroke volume and vascular resistance persisted. The results indicated a beneficial effect of felodipine in the treatment of heart failure, but further studies are needed.

Adult↗
PubMed1986

Increased plasma levels of atrial natriuretic peptide in patients with congestive heart failure.

Atrial natriuretic peptide (ANP) is a recently discovered hormone, originating from atrial myocardium. The peptide (or family of peptides) induces potent diuretic/natriuretic, vasorelaxing and aldosterone inhibitory effects. We have investigated plasma concentrations of immunoreactive ANP in 10 patients with congestive heart failure (CHF). Mean plasma ANP concentrations were more than three times higher in CHF patients than in a matched control group. High plasma ANP concentrations in pathophysiological conditions with a high preload combined with salt and water retention is consistent with a physiological role of this hormone to correct hypervolemia by causing natriuresis and diuresis. It is concluded that ANP homeostasis is altered in patients with CHF and that this hormone may be of importance in the pathophysiology of CHF.

Atrial Natriuretic Factor↗
PubMed1986

[Value of nuclear magnetic resonance tomography and first-pass radionuclide ventriculography in cardiomyopathies].

12 patients with cardiomyopathy were examined by MRT and first pass angiocardiography. MRT provides detailed images of cardiac anatomy and abnormalities without using any contrast medium. The first pass method is an excellent complement to MRT. The functional imaging describes regional wall motion of myocardium exactly. Both non-invasive methods are useful for the diagnosis of cardiomyopathy.

Cardiac Output↗
PubMed1986

Central haemodynamics in acute myocardial infarction. Natural history, relation to enzyme release and effects of metoprolol.

The aim of this investigation was to study central haemodynamics in initially uncomplicated acute myocardial infarction (AMI) with respect to natural history, relation to enzyme estimated infarct size, mortality and effects of metoprolol. A total of 212 patients with AMI but without clinical signs of serious heart failure or hypotension and with a mean delay from onset of pain to study entry of about 7 hours were studied. They were randomised to placebo or metoprolol (15 mg i.v. + 50 mg orally q.i.d.) treatment. Central pressures and cardiac output were evaluated by repeated measurements over 24 hours by means of pulmonary artery catheters. The pharmacokinetics of metoprolol were studied in further 20 patients with AMI. The natural history, as reflected by the placebo group, was observed to be a gradual significant fall in systemic artery pressures, pulmonary capillary wedge pressure (PCWP; 13.6-10.5 mmHg) and stroke volume, while heart rate increased, leaving cardiac output unchanged. The decrease in PCWP was confined to the group with baseline pressure above the median of 13 mmHg and was of equal magnitude in the group given concomitant medication to that of those who required no such therapy. Significant but weak correlations between the peak serum aspartate aminotransferase level and the baseline PCWP (r = 0.28) and stroke volume (r = 0.22) were found. Non-survivors had a significant baseline depression of cardiac output and stroke volume, while PCWP was increased. However, the overlap with survivors was large. The dosage of metoprolol used resulted in mean plasma levels of about 200 nmol/l, which should induce a rapid and sustained degree of beta-blockade. The patients randomised to placebo or metoprolol were assessed according to initial heart rate. The haemodynamic changes induced by metoprolol were similar but were more pronounced in patients with high heart rate compared to those with low rate. In patients with heart rate greater than 65 beats/min, the metoprolol treated group, in comparison to the placebo group, was characterised by a decrease of 10-20% in systolic artery pressure and heart rate, suggesting a decreased myocardial oxygen consumption. Cardiac index (2.9-2.2 l/min/m2) and stroke volume index (36-32 ml/beat/m2) decreased to a minimum after 30 minutes and gradually rose thereafter. The PCWP increased from 13.7 to 15.4 mmHg, 30 minutes after the injection of metoprolol. This increase was confined to the group with baseline low pressure and the difference compared to the placebo group disappeared after 8 hours.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗
PubMed1986

[Diagnosis of thyroid diseases using imaging procedures with reference to nuclear magnetic resonance tomography].

Results of MR imaging performed in 74 patients with diseases of the thyroid gland and in normal persons are compared with nuclear medicine (99mTc 04 and 131J scans) and sonography (5 and 7.5 MHz transducers, linear scans) results. The MR-signal intensity of hot nodules--Plummers' disease--is not specific. Therefore scintigraphy combined with sonography remain the methods of choice for the diagnosis of hyperfunctioning nodules. Morphologic alterations within the thyroid gland are detected by MRT as well as by ultrasound. But when lesions are not limited to the thyroid bed MRT will become the imaging examination of choice. Therefore MRT can be useful for scanning retrotracheal and superior mediastinal extent of thyroid lesions. Also clinically inapparent metastases to the cervical and mediastinal nodes may be detected.

Adenoma↗
PubMed1986

[Role of nuclear magnetic resonance tomography in the diagnosis of renal diseases].

The new non-invasive imaging method MRI makes multidimensional image-display possible without using any radiation and contrast media. An improved technique results in an excellent differentiation of renal structure and renal anatomic details. The multiplanar display could be very helpful to improve the staging of malignant tumors. Inflammations of the kidney produce a significant change of relaxation times. The different signals of cortex and medulla disappear especially in chronic glomerulonephritis, tubular necrosis and transplant rejection. In these instances MRI can essentially contribute to renal diagnostic imaging. Furthermore using fast sequences functional imaging of the kidney will be possible.

Humans↗
PubMed1985

Rupture of the myocardium. Occurrence and risk factors.

The occurrence of myocardial rupture was studied in a well defined unselected population of patients with acute myocardial infarction, and the group of patients who died of rupture of the heart were compared with two control groups. Of a total of 3960 patients, 1746 (44%) fulfilled the diagnostic criteria for acute myocardial infarction. Rupture was defined solely on the basis of the presence of a pathological passage through part of the myocardium, either the free wall of the left ventricle or the septum, found at necropsy or during operation. Two controls were selected for each patient and matched for age and sex, one (control group A) with acute myocardial infarction having died in hospital but not of rupture (non-rupture cardiac death) and one (control group B) with acute myocardial infarction having survived the hospital stay. Necropsy was performed in 75% of all fatal cases with acute myocardial infarction. The total hospital mortality was 19%, the highest mortality being among women over 70 years (29%). Ruptures (n = 56) were found in 17% of the hospital deaths, or 3.2% of all cases of acute myocardial infarction. Women aged less than 70 had the highest incidence of rupture, 42% of deaths being due to rupture. The mean age for patients with rupture and controls was 70.5 years. The median time after admission to death was approximately 50 hours for patients and control group A. Thirty per cent of the patients with rupture occurred within 24 hours of the initial symptoms occurring. Angina and previous acute myocardial infarction were more common among control group A. Patients with rupture and control group B were mostly relatively free of previous cardiovascular or other diseases (chronic angina pectoris ( > 2 months) and previous myocardial infarction). Sustained hypertension during admission to the coronary care unit was more common in patients than in control group A. Hypotension and shock were more common among control group A. Most (79%) of the patients who subsequently ruptured did not receive any corticosteroids at all during the hospital stay. Severe heart failure and antiarrhythmic treatment were more uncommon among patients than among control group A. Patients with rupture received analgesics approximately three times a day throughout their stay. Control group B received analgesics mostly during the first 24 hours. Thus female patients, patients with first infarcts, and patients with sustained chest pain should be investigated for the possibility of rupture. As many as one third (32%) of ruptures may be subacute, and therefore time is available for diagnosis and surgery.

Aged↗
PubMed1984

Audibility of an artificial third heart sound in relation to its frequency, amplitude, delay from the second heart sound and the experience of the observer.

The possibility of detecting synthetic third heart sounds was studied. A special unit was used that added a sound to a previously recorded phonocardiogram. The sound could be changed in frequency, amplitude and delay from the second heart sound. Four groups of observers--cardiologists, residents, nurses and students--listened to 32 random examples. Detection rate increased with experience of the observer (p less than 0.0001) as well as with amplitude (p less than 0.0001), frequency (p less than 0.0001) and delay of the sound (p less than 0.05). The sensitivity was highest among the cardiologists, but the specificity was not different between the groups. Data from this study indicate that the audibility of the third heart sound depends on several important factors. The sound should usually be audible, but variability of results were considerable even among experienced cardiologists. A quantified phonocardiographic recording should be used for validation.

Cardiology↗
PubMed1984

[Computer-aided evaluation of ultrasonic images of the thyroid].

Forty-two patients are described. The ultrasound patterns of normal and pathologically changed thyroid glands have been analysed with the aid of a computer. Using several parameters such as run-length histograms, brightness-histograms, middle run length and standard deviation, we are able to classify the patterns of a thyroid lobe or of a part of it into 4 or 5 major groups. The estimation of the benign or malignant character of the lesions with the used parameters must be controlled by further investigation.

Adenoma↗
PubMedDate not supplied

Selection of patients for randomized controlled trials: implications of wide or narrow eligibility criteria.

This paper discusses the various philosophies that influence the selection of patients for entry into randomized controlled trials. Although a number of different and often competing issues have to be considered depending upon the trial, keeping entry criteria simple, wide and at times even flexible is usually preferable. Such a strategy can be a positive virtue by helping to attain the large numbers of patients that are usually needed to reliably detect the sorts of moderate benefits that are plausible, at a reasonable cost and by providing answers that are relevant to many different categories of patients with a particular condition.

Bias↗
PubMedDate not supplied

Magnetic resonance of the disk of the temporomandibular joint. MR imaging protocol.

Disk displacement can be well detected using proton density-weighted and T2*-weighted two-dimensional gradient-echo sequences. In uncertain cases, especially if the bilaminar zone is not sufficiently represented, a contrast-enhanced T1-weighted spin-echo sequence should also be performed. Also in patients with disk degeneration and osteoarthritis of the temporomandibular joint, proton density-weighted and T2*-weighted two-dimensional gradient-echo sequences are of great diagnostic value. In this collective, however, T1-weighted contrast-enhanced spin-echo sequences should be generally performed, to demonstrate inflammatory reaction of the synovia.

Adolescent↗