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Biomedical subjects

R Felix

Publications and source records attributed to R Felix.

At least 847 records · Page 47Linked to original sources
PubMed1978

[Functional scintigraphy during contraction of the left ventricle. III. Findings in patients with coronary heart disease (author's transl)].

Left ventricular volume curves were measured by a noninvasive technique after equilibration of 99m TC human serum albumin in 27 patients with angiographically proven coronary heart disease. Compared with normals, patients with coronary insufficiency showed a significant reduction in the ejection fraction and of maximal emptying and filling times of the left ventricle during rest. In mildly affected patients with normal ejection fractions, maximal filling was already reduced in keeping with the well known loss of compliance of the left ventricle due to coronary disease.

Cardiac Volume↗
PubMed1978

[Fast computer tomography for investigation of the heart--"computer cardiotomography". Methods and early results (author's transl)].

The early results in the investigation of normal and pathological hearts using fast computer tomography are presented. By means of tomographic sections of cadaver hearts, it has been shown that it is possible to distinguish the ventricular cavities and individual cardiac walls by this non-invasive method. Changes in volume of the ventricles and atria due to various forms of stress are easily distinguishable. Myocardial scars can be distinguished from other circumscribed myocardial defects. The particular advantages of this method, which is non-invasive, painless and easily repeatable, do not need to be stressed. The technique adds a significant dimension to previously available non-invasive diagnostic methods, such as ultrasound echo-cardiography.

Aortic Valve↗
PubMed1978

[Phantom measurements of spatial resolution and the partial-volume-effect in computer tomography (author's transl)].

The present work deals with the problem of demonstrating tissue changes of small volume by computer tomography. Measurements were carried out with the Somatom computer tomograph and evaluated by the Evaluscope (both Siemens); fourteen test situations were devised, using plexiglass rods of varying diameter and different penetration into the level being sectioned. Quantitative relationships were found concerning the spatial resolution for objects of varying sizes, concerning the partial volume effect and the thickness of the section for objects of varying size, and concerning the relationship between resolution and partial volume effect for small objects.

Models, Structural↗
PubMed1978

Aerobic glycolysis in bone: lactic acid production by rat calvaria cells in culture.

Considerable data have been accumulated on aerobic glycolysis of intact bone preparations. To test whether aerobic glycolysis is a feature of the bone cells themselves or of the localized conditions within an intact bone, cells isolated from rat calvaria were cultured and the effect of several factors on lactate production was determined. These cells drastically decreased lactate production when the pH in the culture medium was lowered, changing from 100 to 20 percent for a pH shift from 7.4 to 6.75. L-lactate inhibited its own formation by 40 percent at 20 mM. Parathyroid hormone (PTH) (820 U/mg) at a concentration ranging from 0.2 to 5.0 U/ml stimulated slightly the lactate production in a log-linear response, the ratio treated over control changing from 1.1 to 1.3. The maximal stimulation is observed at pH 7.0. Isolated cells respond qualitatively the same as did intact calvaria. Quantitatively, there were significant differences: notably, a smaller response to parathyroid hormone and a higher sensitivity to lowered pH.

Aerobiosis↗
PubMed1978

[Results of myocardial perfusion scintigraphy (author's transl)].

Myocardial perfusion scintigraphy by means of the microsphere technique is a valuable method for detecting regional myocardial scars. The use of the microsphere technique is indicated in all patients who have had myocardial infarction and before coronary bypass operations. In a certain group of patients with severe but atypical angina pectoris and a normal coronary arteriogram and in some arrhythmias the perfusion scintigram can provide information on changes coronary microcirculation. The assessment of myocardial blood flow redistribution under pharmacological intervention is a further indication for the microsphere technique.

Angina Pectoris↗
PubMed1978

[Comparison between computer tomography and ultrasound in abdominal and renal growing and displacing processes (author's transl)].

The advantages and limitations of both methods are analyzed and compared. The comparison is effected on the basis of the present standard of equipment. The results obtained with both methods are demonstrated by means of the example of frequent epigastric diseases. Despite the still limited number of patients examined simultaneously both by ultrasound and computer tomography, it seems that the sensitivity of both methods in case of growing and displacing processes in the epigastric or renal regions, does not differ greatly. A comparison of the specificity of both methods will be effected only after a large number of patients has been examined by both methods at the same time.

Abdominal Neoplasms↗
PubMed1978

[Extension of thoracal diagnostics through computer tomography (author's transl)].

The utilization of transverse layers in computer tomography opens up a new level of examination for localization of pathologic processes in the thorax and their spread. The good resolution of roentgen absorption differences in the soft parts enables the use of computer tomography in the diagnosis of pericardial effusions and for further differentiation of known mediastinal growing and displacing processes. This method is also suitable for the identification of aneurysms, since it is not invasive and places hardly any strain on the patient. Finally, computer tomography can also be used for radiotherapy and operation planning, as well as in target biopsy on account of the true-to-scale and reproducible image of the body cross-sections.

Aortic Diseases↗
PubMed1978

[Myocardial perfusion scintigraphy - methods and fundamentals (author's transl)].

Myocardial perfusion studies with labelled particles make a detailed analysis of the distribution of myocardial perfusion possible. Methodical and physiological fundamentals are described and the reliability of the method is shown by double radionuclide imaging. LAD-stenoses (greater than 70%) show a decreased activity in the distal areas of the LAD (on the average 36,5 +/- 10,3% in contrast to 59 +/- in normals). Mean local activity is 14,9 +/- 1,8% within scars. Scars and hemodynamically effective stenoses can be imaged with high sensitivity. Total defects (smaller than 15% of the activity maximum) correspond to a scar. A moderate reduction of uptake (15--50% of the activity maximum) does not allow any differentiation between scar and reversible diminution of perfusion.

Coronary Circulation↗
PubMed1978

[Roentgen diagnosis of pulmonary embolism and infarct (author's transl)].

Systematic classification of roentgen signs according to anatomical and functional alterations is described as follows: Direct roentgen signs of embolism without hemorrhage and without infarction, indirect roentgen signs of embolism without hemorrhage and without infarction, indirect roentgen signs of embolism with hemorrhage, indirect roentgen signs of embolism with infarction, and roentgen signs of microembolism. Diagnostic security of conventional chest films, technique and "timing" of pulmonary angiography, direct and indirect roentgen signs of embolism in pulmonary angiography, and traumatic fat embolism are described.

Diagnosis, Differential↗
PubMed1977

[Reversible pulmonary arterial hypertension after medication of aminorexfumarate (author's transl)].

It is reported on a patient who 8 years ago and 42 developed a primary pulmonary arterial hypertension after medication with medicaiton with aminorefumarate, an antiappetizing compound whose structure is similar to ephedrine. A control measurement of the pulmonary artery pressure 8 years later showed normal values for the pressure in the right cavities and in the pulmonary artery. Beside a short term medication with nitro compounds no further medication was given. The case in one of the very few with primary pulmonary arterial hypertension where a normalization of the pulmonary artery pressure could be documented.

Aminorex↗
PubMed1977

[Abnormal myocardial blood flow pattern after non-transmural infarction (author's transl)].

While coronary angiography was within normal limits in three patients with recurrent severe attacks of angina and non-transmural postero-lateral wall myocardial infarction, myocardial perfusion scintigraphy demonstrated an abnormal distribution pattern. In addition to recanalised thrombosis, embolism or spasm, abnormalities in the microcirculation are possible causes of the discrepancy between the coronary arteriogram and the scintigram. Myocardial perfusion scintigraphy is of particular diagnostic significance in this group of patients with coronary heart disease but normal coronary angiography. Treatment in the presence of this finding consists of administration of platelet-aggregation inhibitors.

Adult↗
PubMed1977

[Compromized myocardial perfusion in arrhythmias (author's transl)].

In 7 patients with arrhythmias of various origin the myocardial scintigram displayed either a diffuse or circumscript defect of the perfusion. The coronary arteriogram was normal in all patients. The localized defect of the perfusion in 2 patients was in the region of the upper part of the interventricular septum. Both had a left bundle brunch block. A correlation between the perfusion defect and the electrophysiological abnormality seems probable. The perfusion defect in one of the patients is most probably caused by a previous myocarditis followed by fibrous changes. In the other 6 patients the cause for the perfusion defect is not obvious. A history of myocarditis is missing. The presence of "small vessel disease" in those patients has however to be considered. Our results point to the relation between an abnormality of the microcirculation and arrhythmias in younger patients.

Adult↗