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Biomedical subjects

M Baud

Publications and source records attributed to M Baud.

At least 37 records · Page 2Linked to original sources
PubMed1993

[Preventive effect of an immunomodulator, OM-85 BV, on acute exacerbations of chronic bronchitis in elderly patients. Preliminary results at six months in 291 patients].

Three hundred fifty six patients aged 65 years or more (mean age 81.8 years) who were suffering from chronic bronchitis were included in a double-blind trial against placebo to assess the preventative effect of OM-85 BV against acute exacerbations of chronic bronchitis. OM-85 BV is an immunostimulant composed of lyophilised factions of 8 bacteria which are most frequently encountered during the course of respiratory tract infections. 291 patients completed the study. In the group treated by OM-85 BV, a significant increase in the number of patients with no episode of acute bronchitis was noted (96 versus 71, p = 0.006). There was a 38.8% reduction in the absolute numbers of episodes of acute bronchitis and a 33% reduction in the number of prescriptions for antibiotics, however there was no difference in the number of pneumonias and bronchopneumonias. These results show the protective effect of OM-85 BV against bronchial superinfections in a large population of elderly patients suffering from chronic bronchitis.

Acute Disease↗
PubMed1992

Effects of doxapram on hypercapnic response during weaning from mechanical ventilation in COPD patients.

Failure of weaning from mechanical ventilation in COPD patients is often related to diaphragmatic fatigue. Whether there is a central respiratory drive fatigue and a reserve of excitability is still debated. The purpose of this study was to analyze the following in 13 COPD patients weaned from mechanical ventilation: (1) ventilatory (VE/PETCO2) and neuromuscular (P0.1/PETCO2) response to hypercapnia; (2) the maximum reserve capacity measured through changes in the VE/PETCO2 and P0.1/PETCO2 slopes after doxapram (DXP) infusion, which, given during the test, allows measurement of the maximum response capacity to overstimulation; and (3) analyze the influence of these changes on the outcome of weaning. The results show a variable P0.1/PETCO2 response and a low VE/PETCO2. DXP infusion does not change the slopes of these relations but increases the end-expiratory volume (delta FRCd); (p less than 0.02). Since there was no change in the VE/PETCO2, P0.1/PETCO2, and delta FRC values with or without DXP, there was no excitability reserve in patients who were successfully weaned. When weaning failed, DXP did not change VE/PETCO2 and P0.1/PETCO2 slope, but delta FRCd was greater the delta FRC (p less than 0.001). The excitability reserve in these patients leads to an increase in end-expiratory volume, probably worsening the diaphragm dysfunction.

Aged↗
PubMed1991

Transforming signals into quantitative values and mathematical treatment of data.

The purpose of this article is to review some mathematical models which are available to calibrate immunoassays and interpolate analyte concentration. Several curve fitting methods are available, but few of them are currently used. Point-to-point linear interpolation is prone to bias when the rate of curvature of the calibration curve or when the random error are high. Polygonal interpolation connects each neighboring pair of data points with multiple connected line segments. Neither smooths the data. Smoothing models are often preferred because they can correct some of the random error. Weighted least squares must be used when the calibration points have nonhomogeneous variance. The most used methods are empirical (spline function) or semi-empirical (logit-log, logistic). The logitlog straight line is often too rigid. Logistic equation can fit numerous assays. The best empirical model is the smoothed cubic spline. Model-based methods attempt to describe the data in terms of a given theoretical model for the assay chemistry. The choice of a method to efficiently control calculations must take into account the quality of the fit, the robustness with outliers, the proper computation of confidence limits and the user-friendliness. Errors associated with the different processing steps can also be due to the calibration point distribution, the axes in which the curve is shown, the model used, and, of course the measurement errors.

Data Interpretation, Statistical↗
PubMed1991

[Broncholithiasis of the upper right lobe].

A case of right upper lobe broncholithiasis is reported in a 50 years old smoker man. The first diagnosis was bronchial carcinoma but the diagnosis was made finally by fiberoptic bronchoscopy and scannography. The outcome remains favourable without treatment. The value of scannography for diagnosis and follow-up is underlined.

Bronchial Diseases↗
PubMed1989

[Hyperoxia test during attempts to withdraw artificial ventilation].

A 30 minute test of hyperoxia (10 l.min-1) was conducted in patients (n = 21) with chronic obstructive lung disease during the weaning trials from mechanical ventilation. Two groups were formed according to whether the occlusion pressure at 100 ms (PO.1), index of central stimulation, decreased or not during the test. The first group lowered PO.1 and increased PaCO2 by decreasing VE (minute-ventilation), VA (alveolar ventilation) and increasing the VD/VT ratio; the others had a lower PO.1 and did not modify it after administration of 02 despite a lowered PaO2 initially identical to that in the first group. They held PaCO2 constant by increasing VE and by maintaining VA in relationship with an improvement in diaphragm contractility and/or a better response to hypercapnia stimulus. All the patients is this group were successfully weaned eight days after the study period.

Aged↗
PubMed1988

Comparison between vertical parallel hole collimator and 30 degrees rotating slant hole collimator for assessing global and regional left ventricular function by radionuclide angiography.

Left ventricular ejection fraction (LVEF) and regional wall motion abnormalities were determined in 40 patients (30 with coronary artery disease and 10 with valvular heart disease) using equilibrium radionuclide angiography. Scintigraphic acquisitions were collected in random order with 2 different collimators as follows: in anterior face (AF), left anterior oblique (25 degrees-45 degrees LAO) and 70 degrees LAO, with a vertical parallel hole collimator (VTC), and in 25 degrees-45 degrees LAO and 65 degrees-80 degrees LAO with a 30 degrees rotating slant hole collimator (RSHC), with the slant of the collimator directed towards the cardiac apex in both projections. Results were compared to contrast ventriculography (CV) performed in the 30 degrees right anterior view (3 segments: anterior, apical, inferior) and in a 60 degrees left anterior oblique view (3 segments: septal, apical and lateral). Radionuclide LVEF in both series was closely correlated with contrast ventriculographic LVEF (r = 0.89, VTC vs CV and r = 0.87, RSHC vs CV, respectively). Regional wall motion analysis was only performed among the 30 patients suffering from coronary heart disease. Eight contrast angiographic studies were normal and 22 abnormal. Global sensitivity and specificity were 100% and 63% with the VTC (3 false positives) and 91% and 87% with the 30 degrees RSHC (2 false negatives and 1 false positive, P = ns). Agreement for the localisation of the regional wall motion abnormalities between CV and radionuclide angiography was 70.6% with the VTC and 71.2% with the RSHC (P = ns).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Disease↗
PubMed1988

[Exertion-induced parameters of left ventricular function in patients with chronic cardiac insufficiency. An isotope study].

Exercise-induced changes in haemodynamic values were studied by radionuclide ventriculography in 21 patients with permanent systolic dysfunction (15 with non-obstructive cardiomyopathy and 6 with ischaemic heart disease). The results were compared with those obtained in 8 control subjects with normal heart. In healthy subjects, during exercise the ejection fraction increased due to constant diminution of the end-systolic volume; the end-diastolic volume and the systolic ejection volume did not significantly vary; the cardiac output augmented only because of the accelerated heart rate. In patients with permanent left ventricular dysfunction, the ejection fraction remained unchanged during exercise, whereas the end-systolic volume increased significantly. Yet the systolic ejection volume increased due to a rise in end-diastolic volume. Heart rate and cardiac index increased, but not as much as in normal subjects. There was a close correlation between changes in end-diastolic and end-systolic volumes. It was the relative importance of changes in these two ventricular volumes that determined the direction and amplitude of variations in ejection fraction. It is concluded that in patients with permanent left ventricular dysfunction: (1) the end-systolic volume increases during exercise, thus betraying a worsening of the systolic dysfunction; (2) however, the systolic ejection volume is maintained or increases due to an increase in end-diastolic volume; (3) the changes in ejection fraction observed during exercise are of little value to characterize the modifications that occur in left ventricular work performance.

Adult↗
PubMed1986

[Aspergillosis with obstruction of the central airways].

Two cases are reported of obstruction of central airways by plugs containing Aspergillus fumigatus. In one case the obstruction was located in the right stem bronchus and, despite treatment with amphotericin B, the immunocompromised patient died from invasive disseminated aspergillosis. In the other case the obstruction was in the trachea and, since the immune function of the patient was normal, she responded favorably to treatment by amphotericin B.

Adolescent↗
PubMed1985

[Determination of ventricular volumes by a non-geometric method using gamma-cineangiography].

The authors suggest a new way of determining ventricular volume by a non-geometric method using gamma-cineangiography. The results obtained by this method were compared with those obtained by a geometric methods and contrast ventriculography in 94 patients. The new non-geometric method supposes that the radioactive tracer is evenly distributed in the cardiovascular system so that blood radioactivity levels can be measured. The ventricular volume is then equal to the ratio of radioactivity in the LV zone to that of 1 ml of blood. Comparison of the radionuclide and angiographic data in the first 60 patients showed systematic values--despite a satisfactory statistical correlation (r = 0.87, y = 0.30 X + 6.3). This underestimation is due to the phenomenon of attenuation related to the depth of the heart in the thoracic cage and to autoabsorption at source, the degree of which depends on the ventricular volume. An empirical method of calculation allows correction for these factors by taking into account absorption in the tissues by relating to body surface area and autoabsorption at source by correcting for the surface of isotopic ventricular projection expressed in pixels. Using the data of this empirical method, the correction formula for radionuclide ventricular volume is obtained by a multiple linear regression: corrected radionuclide volume = K X measured radionuclide volume (Formula: see text). This formula was applied in the following 34 patients. The correlation between the uncorrected and corrected radionuclide volumes and the angiographic volumes was improved (r = 0.65 vs r = 0.94) and the values were more accurate (y = 0.18 X + 26 vs y = 0.96 X + 1.5).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Factors influencing the quantification of valvular regurgitation by gated equilibrium radionuclide angiography.

To test the clinical validity of the stroke volume ratio (SVR) and the factors influencing its value we determined it in a population of 41 patients free of valvular regurgitation. The SVR was estimated from multigated blood pool scans in left anterior oblique position by two methods. The first method followed the classical formula of the left to right ventricular stroke count ratio. The second method used the same formula except that the right atrial activity emanating from the area of right atrioventricular overlap as traced at right ventricular end-systole, was subtracted from the right ventricular stroke count. The SVR averaged 1.25 +/- 0.18 (range 0.97-1.80) by the first technique and 1.05 +/- 0.12 (range 0.82-1.36) by the second (P less than 0.001). In our results the SVR is not correlated to either ejection fraction or angiographically determined left ventricular volumes. Conversely the SVR is correlated with the left to right end-diastolic volume ratio evaluated from radionuclide counts measured at right and left ventricular end-diastole (r = 0.48, P less than 0.01). This may be due to variations in the area of right atrioventricular overlap, depending on the size of the ventricular chamber. It is postulated that the accuracy of SVR determination could be enhanced by subtraction of the right atrial activity from the right ventricular activity at end-systole. In patients free of valvular regurgitation the LV/RV stroke volume ratio approaches unity and the variability of the results is smaller. Interobserver and intraobserver variability is reduced using the Fourier phase approach.

Aortic Valve Insufficiency↗
PubMed1981

Scintigraphic image contrast-enhancement techniques: global and local area histogram equalization.

This article develops two contrast-modification techniques for the display of scintigraphic images. Based on histogram-modification techniques, histogram equalization, where each level of gray is used to the same extent, gives maximum entropy. The first technique uses the application of histogram equalization in the whole image. To eliminate contrast attenuation small but important portion of the gray scale histogram, local area histogram equalization has been applied to images with differences in intensity. Both techniques were tested using a phantom with known characteristics. The global equalization technique is more suitable to bone scintigraphies, and some well-chosen boundaries improved the difference between two comparable areas. For liver scintigraphies, where intensity is quite equal in every pixel, a local area equalization was chosen that allowed detection of heterogeneous structures. The images resulting from histogram-equalization techniques improve the readability of data, but are often far from usual images and necessitate an apprenticeship for the physician.

Bone and Bones↗