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Biomedical subjects

M Baud

Publications and source records attributed to M Baud.

52 records · Page 3Linked to original sources
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↗
PubMed1981

Inhibition by two diphosphonates of bone lysis in tumor-conditioned media.

In order to test the effect of diphosphonates in inhibiting bone lysis induced by human tumors, neonatal mouse calvaria are cultured in sterile conditions in different media. Osteolysis is estimated by the amount of 45Ca released from bone to medium, the mice being given injections of 45Ca on their day of birth. An increased bone lysis is observed when calvaria are incubated in the same medium conditioned from cultured tumor fragments. This effect is significantly decreased when the mice have been treated with either ethanehydroxydiphosphonate or dichloromethylenediphosphonate. These experiments represent a first step in estimating the potential effects of different drugs on malignant osteolysis.

Animals↗
PubMed1981

[Comparison of 2 methods of determining the kinetics of a bicompartmental system. Application to the measurement of cutaneous blood flow].

Peeling method and a non linear regressions method (Newton's method) have been tested on experimental and simulated data. Newton's method is the most accurate and precise when running on simulated data. Experimental curves artefacts make Newton's algorithm automatically running less efficient than classical peeling algorithm working in interactive mode.

Blood Flow Velocity↗
PubMed1979

[Cutaneous and subcutaneous blood flow measurement in rabbit's ear by epicutaneous diffusion of xenon 133. Influence of the arteriovenous anastomosis].

The cutaneous and subcutaneous blood flow measurement by a diffusible inert gas concerns theorically capillary nutritional flow. In clinical routine, where pathological openning of arteriovenous anastomosis is suspected, the blood flows measured by Xenon technic are often increased. The function of the shunts are displayed on the epuration curve obtained on a region where there are numerous: rabbit's ear.

Animals↗
PubMedDate not supplied

Ultrastructural apoptotic lesions induced in bone marrow after neptunium-237 contamination.

This study describes the ultrastructure of lesions induced by neptunium-237 (237Np), a by-product of uranium in nuclear reactors, in the bone marrow. A group of rats were given a single injection of 237Np-nitrate solution in order to observe the acute toxicity effects of this actinide. Electron microscopy was used to describe the different lesions. Observations included the swelling of the cell membrane, nuclear membrane lyses, abnormal chromatin condensation or nucleus convolution. These ultrastructural alterations of the nucleus and the cellular membrane appeared shortly after treatment. This study demonstrates the toxic effects of neptunium and its implication in the induction of apoptosis in bone marrow.

Animals↗
PubMedDate not supplied

[Are desquamated trophoblastic cells retrieved from the cervix suitable for a prenatal diagnosis?].

Prenatal diagnosis based on sampling of fetal tissues, amniotic fluid or chorionic villi is associated with the risk of miscarriage and fetal damage. These risks would be avoided if diagnosis could be performed in desquamated trophoblast cells recovered non-invasively from the maternal cervix. We report on our experience of fetal karyotyping on endocervical lavage using in situ hybridization (FISH) and DNA amplification (PCR) fetal sex was correctly predicted in 8/10 cases by FISH and in 6/10 by PCR. FISH appeared to be a reliable technique for karyotyping when trophoblast can be recovered from the maternal endocervix (8/10).

Female↗