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Biomedical subjects

W Kedra

Publications and source records attributed to W Kedra.

10 recordsLinked to original sources
PubMed1998

A new quantitative D-dimer assay appropriate in emergency: reliability of the assay for pulmonary embolism exclusion diagnosis.

Plasma D-dimers, degradation products of cross-linked fibrin, are elevated in several thrombotic diseases. In the last decade, their measurement has been performed with specific monoclonal antibody based ELISA assay, with a high negative predictive value of such pathologies. However these methods have a low clinical impact since they cannot be used in emergency because they are time consuming and require series. Recently, rapid tests have been proposed with similar accuracy and are feasible for use in emergency conditions. The aim of our study was to evaluate the potential value of a new quantitative rapid assay, based on agglutination of latex microparticles coated with two monoclonal antibodies specific for D-dimers (Liatest D-Di, Diagnostica Stago), in the exclusion diagnosis of pulmonary embolism (PE). Eighty-five consecutive suspected PE patients were included in the study. D-dimer determination was performed with both standard ELISA and Liatest D-Di just before pulmonary scintigraphy. Sixty-nine patients were free of PE and 16 had PE. Our results confirm the excellent sensitivity and negative predictive values of the conventional D-dimer ELISA. Using a cut-off value of 500 ng/ml, the sensitivity and the negative predictive values of Liatest D-Di were 94% and 96%, respectively. Only one case of PE had a D-dimer value at 480 ng/ml, close to the cut-off value. This study demonstrates that the Liatest D-Di assay is sensitive enough to be used as the first step in the assessment of PE. However, the best cut-off value has to be determined to get an exclusion diagnosis with certainty.

Adult↗
PubMed1995

[Value of the exercise test in the study of arrhythmia].

Exercise testing may be used to assess symptoms occurring on effort, to search for and evaluate arrhythmias or conduction defects, antiarrhythmic drugs, pacemakers or implantable cardioverter defibrillators. Interpretation of exercise testing is difficult because of the complexity of the factors in play. Exercise itself induces changes in myocardial metabolism and the autonomic nervous system, the nature and importance of which are influenced by the underlying cardiac disease and the presence of cardiac failure or myocardial ischaemia. This is particularly true when studying the behaviour of arrhythmias on effort, which depends on many parameters, in that they may appear or disappear during exercise, irrespective of their relationship to autonomic nervous system activation. The main problem lies in the interpretation of changes in the heart rate before the onset of an arrhythmia. The sinus rhythm is both a passive indicator of the vago-sympathetic equilibrium and one of the determining factor of the arrhythmia (relationship to the rate), but it is, itself, dependent on the presence of myocardial dysfunction, a source of arrhythmias, and its changes then become difficult to interpret. These reasons explain why exercise testing is certainly a valuable tool in assessing arrhythmias but the poor reproducibility, especially in the evaluation of ventricular arrhythmias, advises prudence in the interpretation of results.

Arrhythmias, Cardiac↗
PubMed1994

Ex vivo inhibition of platelet aggregation in patients with severe limb arteriopathy treated with BAY U3405, a specific TX A2 receptor antagonist.

A double-blind, placebo-controlled randomized study with BAY U3405, a specific thromboxane A2 (TX A2) receptor blocker, was performed in patients suffering from severe stade II limb arteriopathy. BAY U3405 or placebo was administered in 16 patients at 20 mg four times a day (from day 1 to day 3). Hemostatic studies were done before therapy, and on day 2 and day 3 under therapy. On day 3, BAY U3405 was shown to induce a highly statistically significant decrease of the velocity and the intensity of the aggregations mediated by arachidonic acid (56 +/- 37% for the velocity, 58 +/- 26% for the intensity) or by U46619 endoperoxide analogue (36 +/- 35% for the velocity, 37 +/- 27% for the intensity). Similar results were already observed on day 2. By contrast, such a decrease was not noticed with ADP mediated platelet aggregation. Furthermore, plasma levels of betathromboglobulin and platelet factor 4 remained unchanged. Peripheral hemodynamic parameters were also studied. The peripheral blood flow was measured using a Doppler ultrasound; the pain free walking distance and the total walking ability distance were determined under standardized conditions on a treadmill. These last two parameters show a trend to improvement which nevertheless was not statistically significant. All together these results encourage further in vivo studies using BAY U3405 or related compounds on a long-term administration.

Adult↗
PubMed1993

Relationship between birth weight and umbilical Doppler blood flow velocity waveforms during the third trimester of pregnancy.

OBJECTIVES: The Doppler ultrasound method for recording blood flow velocity waveforms in the fetal umbilical arteries is now widely used as an indicator of fetal well-being. This study was conducted to investigate the impact of umbilical placental resistance level on fetal growth development. METHODS: Maximal flow velocity waveforms were recorded from the umbilical artery in 108 pregnant women including 50 with normal pregnancies, 3 with previous death in utero, and 55 with moderate arterial hypertension corrected by resting only. All the newborn infants had a normal birth weight (BW between the 10th and the 90th percentile for the gestational age at birth). Doppler measurements were performed between 25 to 38 weeks of gestation. The placental resistance index (PRI) derived from blood flow velocity measurements was determined. RESULTS: Data were grouped in two-week intervals according to the age of gestation at Doppler examination. We found an inverse close relationship between BW and PRI which can be described by a linear function of PRI in each interval. BW increased with the decrease in PRI. CONCLUSIONS: Our findings suggest that umbilical placental resistance level determines fetal growth development and birth weight during pregnancies without placental insufficiency.

Birth Weight↗
PubMed1989

Blood flow through the brachial artery at different temperatures in patients with Raynaud's phenomenon.

Blood flow through the brachial and radial artery at different temperatures and during reactive hyperaemia was measured in 23 patients with Raynaud's phenomenon (9 patients with Raynaud's disease, 7 - Raynaud's syndrome with thoracic outlet syndrome (TOS), and 8 - Raynaud's syndrome and scleroderma), and 11 control subjects. Blood flow was determined by an ALVAR pulse-wave Doppler system enabling measurement of vessel diameter and blood flow rate. The measurements suggest that the blood flow through brachial artery reflects the changes of blood flow through the hand immersed in water of different temperatures. Maximum vasoconstriction was the same in all groups of Raynaud's phenomenon. The lowest blood flow at higher temperatures and during reactive hyperaemia was found in patients with scleroderma, whereas in the group of TOS and partly in patients with Raynaud's disease one can suspect only functional changes.

Adolescent↗
PubMed1988

[Quantitative analysis of ventricular volumes by digital two-dimensional echocardiography].

The purpose of this study was to assess the usefulness of digital enhancement of two-dimensional echocardiographic images by cardiac cycle-synchronized summation and digital manipulation of the resulting images. We developed a system which provides for: (1) real-time storage of end-diastolic and end-systolic cardiac cycle images irrespective of rhythm variations; (2) exclusion from summation of end-diastolic and end-systolic images altered by respiratory movements or transducer displacements; (3) performance on the resulting images of various mathematical operations (3*3 convolutions, colour scale-guided manipulation of grey shades); (4) performance of complex mathematical calculations from the extracted edges including, in particular, reconstruction of ventricular volumes by Simpson's crossed method from a transverse and an apical section or from two apical sections. This method was used to collect echocardiographic images from 32 patients who had undergone left ventricular quantitative angiography during the same week. Qualitatively, digital enhancement of two-dimensional echocardiographic images undoubtedly facilitated the identification of endocardial edges and reduced image noise, notably in patients whose ventricular edges were virtually unrecognizable by any other method. Moreover, summation improved correlations with angiography and reduced the variability of quantitative ventricular volume assessment. Finally, the ease and rapidity with which this "real-time" system can be used enables quantitative analysis of left ventricular function to be routinely carried out.

Adult↗
PubMed1988

[New treatments for Raynaud's syndrome].

Raynaud's phenomenon, either idiopathic or secondary is often severe. It is due to a vasospasm in response to cold, and an increase in sympathetic tone, hyperviscosity and sometimes hyperactivation of platelets and erythrocytes have been reported. New drugs have been developed such as ketanserin, which is a specific inhibitor of serotonin S2 receptors, and has led to a positive response in 38%-80% of patients. The prostaglandins PGE1 and PGI2 were given i.v. in refractory patients and led to a beneficial effect in 50%-70% of cases. These data seem to justify the development of prostaglandin analogues.

Alprostadil↗
PubMed1979

Relationships between hemodynamic profiles and topography of acute myocardial infarction.

Initial hemodynamics were studied in 101 patients with acute myocardial infarction complicated by shock or left heart failure. 59 had anterior myocardial infarction (AMI); 42 had inferior myocardial infarction (IMI). Data were processed by univariate analysis and correspondence analysis. AMIs and IMIs were significantly different on conduction disturbances, heart rate, left ventricular filling pressure, mean pulmonary artery pressure and right ventricular function indices. Both patients and parameters were projected on the most meaningful factorial plane generated by correspondence analysis. This two-dimensional graphical representation showed that all the information was roughly distributed along the 2 orthogonal axes defining this plane. Survivors and nonsurvivors were fairly well separated along the first factorial axis (prognostic axis) which was highly correlated with both outcome and left ventricular function parameters. AMIs and IMIs were grossly separated along the second factorial axis (topographical axis) which was rather well correlated with location and right ventricular function parameters. These studies suggest that AMI and IMI hemodynamic profiles are modulated by the presence or absence of right ventricular dysfunction. Moreover right ventricular dysfunction may be held responsible of some lack of information about left ventricular function status.

Acute Disease↗