Biomedical subjects

P Albarede

Publications and source records attributed to P Albarede.

11 recordsLinked to original sources

PubMed1993

Prognostic value of thallium-201 myocardial scintigraphy after atrial transoesophageal pacing in patients with suspected coronary artery disease.

Fifty-five patients with suspected coronary artery disease underwent planar thallium-201 myocardial scintigraphy after atrial transoesophageal pacing. Coronary angiography was carried out in all patients. Eighteen patients had no myocardial infarction, but a greater than 50% narrowing of at least one main vessel: initial hypoperfusion with redistribution at 4 h occurred in 16 patients (sensitivity 89%). Twenty-one patients had had a previous myocardial infarction: a reversible thallium defect was observed in 12 patients and an irreversible defect in the nine remaining patients. Sixteen patients had normal coronary arteries: a reversible thallium defect was observed in three patients (specificity 81%). After a mean follow-up of 22 +/- 13 months (range 6 to 40), 23 cardiac events occurred: cardiac death in one patient, unstable angina in three, and revascularization procedures for recurrent angina despite medical therapy in 19 (coronary artery bypass surgery in 7 and coronary angioplasty in 12). By univariate analysis, the predictors of future cardiac events were a history of previous myocardial infarction (odds ratio 5.5, P < 0.02), multivessel coronary artery disease (odds ratio 9.6, P < 0.0002), angina during atrial pacing (odds ratio 5.1, P < 0.05), abnormal scintigraphy (odds ratio 17.1, P < 0.001) and reversible perfusion defect after pacing (odds ratio 7.9, P < 0.002). By multivariate analysis, multivessel disease (P < 0.004) and reversible perfusion defect after pacing (P < 0.02) were the only independent predictors of future cardiac events.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1992

Comparison of thallium myocardial scintigraphy after exercise and transoesophageal atrial pacing in the diagnosis of coronary artery disease.

Forty-nine patients admitted for assessment of chest pain underwent coronary angiography, planar Thallium 201 myocardial scintigraphy after submaximal exercise (TE) and transoesophageal atrial pacing (TAP). Early hypofixation with redistribution after 4 h indicated ischaemia. The criterion for a myocardial infarction (MI) was a fixed perfusion defect. Coronary angiography was carried out in all patients. Sixteen patients (group 1) had no MI and over 50% narrowing of at least one main coronary vessel. Ischaemia was noted in 10 of the 16 patients during exercise, and in 14 of the 16 patients during atrial pacing. The sensitivity for the prediction of coronary stenosis was 62% for TE and 87% for TAP. Nineteen patients (group 2) had had a previous MI. Reversible ischaemia was noted in 10 of the 19 patients during exercise, and in 11 of the 19 patients during TAP. Four of 14 patients with normal coronary arteries (group 3) had a reversible ischaemia with TE, and three of these same patients developed a positive scan with TAP. The respective specificities were 71% and 78%. Comparison of segmental hypoperfusion after TE and TAP gave identical results in 72 of the 80 segments studied in group I (90%), and in 88 of the 95 segments studied in group 2 (92%). The localizing value of TAP was good in left anterior descending (12 out of 18) and right coronary disease (16 out of 19), but poor in left circumflex stenosis (3 out of 9) misclassified as right coronary disease in four patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1991

[Value of thallium 201 myocardial scintigraphy under transesophageal atrial stimulation for the diagnosis of coronary disease].

Fifty patients hospitalized for chest pain underwent coronary angiography, and thallium-201 myocardial scintigraphy after exercise (TE) and under transesophageal atrial stimulation (TST). The double product mean during exercise was 2,223 +/- 579 beats x cmHg/min and 2,313 +/- 420 beats x cmHg/min under TST (NS). The criterion of positivity was early hypofixation. Thallium redistribution 4 hours after administration is indicative of reversible ischemia. Thirty-six patients had more than 50% narrowing in at least one of the three principle coronary arteries. The predictive sensitivity for coronary stenosis was 83% for TE and 94% for TST. The respective specificities were 71 and 78%. The comparison of segmental hypoperfusion after exercise and under TST gave similar results in 230 of the 250 segments studied (92%). Thus, TST provides and alternative diagnostic method to TE for the detection of coronary artery disease and can be performed in patients for whom the usual stress test is not possible, most particularly when dipyridamole is counter indicated because of a bronchospastic factor.

Adult↗

PubMed1987

Intracorneal correction of aphakia: paraxial approach at null incidence.

The technique of intracorneal implantation, recently proposed by de Laage de Meux and Cinquin [Implants, 2, 26 (1984)] for the correction of aphakia, is analyzed in terms of geometrical optics. The analysis is done by using matrix optics and by assuming a null incidence. The characteristics (diameter, radii of curvature, axial thickness) of the hard or soft lens to be implanted are determined and given. The aniseikonia of such lenses is shown to be nearly the same as that of contact lenses.

Aphakia↗

PubMed1984

[Antinuclear antibodies: analysis of images and classification of immunofluorescence aspects on nuclei isolated from rat hepatocytes].

Image analysis and Fourier transformation of the various nuclear immunofluorescence patterns observed while detecting antinuclear antibodies allow an objective and quantitative definition of the fluorescence. They also point out various IF types hidden by the main pattern, without having to dilute the test serum. They make obvious the difference between speckled and reticular patterns, and reveal the existence of intermediate states. The usual nuclear IF patterns (homogeneous, ring, nucleolar, reticulated, speckled and diffuse) may be grouped, according to their photo emission, into nuclear and subnuclear patterns. The first group includes homogeneous, annular and passive nucleolar IF. The second group is composed of speckled, reticulated, mixed, and active nucleolar IF. Alternatively, these aspects may be grouped into three types: homogeneous nuclear IF (homogeneous and ring), heterogeneous nuclear IF (speckled, reticulated and mixed) and nucleolar IF (active or passive). Diffusion can affect or not these aspects and does not apply to a special type or pattern. Image analysis and the study of the image spatial spectrum lead to automated recognition of the IF types, and later on, to the discrimination of antinuclear antibodies.

Animals↗

PubMed1968