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Biomedical subjects

J Belenger

Publications and source records attributed to J Belenger.

At least 19 recordsLinked to original sources
PubMed1995

Intra-arterial beta irradiation prevents neointimal hyperplasia in a hypercholesterolemic rabbit restenosis model.

BACKGROUND: Intra-arterial gamma irradiation has been shown to reduce restenosis after balloon angioplasty. The use of beta emitters should allow similar effects while inducing less undue tissue irradiation radioprotection problems. METHODS AND RESULTS: Flexible 90-yttrium (90Y) coils inside a centering balloon were used to allow homogeneous intraarterial dose delivery. One carotid and one iliac artery of 21 hypercholesterolemic rabbits were deendothelialized and then irradiated. Four dose schedules were studied: (1) control (dilated, nonirradiated); (2) 6 Gy; (3) 12 Gy; and (4) 18 Gy. Arterial specimens were histologically evaluated at 8 days and at 6 weeks. For all radiation doses at 8 days compared with controls, there was a significant decrease in bromodeoxyuridine-labeled cells (245 +/- 93 cells/cm in control, 42 +/- 27 in 6 Gy, 72 +/- 107 in 12 Gy, and 2 +/- 2 in 18 Gy groups; P < .001) and in total neointimal cells (891 +/- 415 cells/cm in control, 79 +/- 43 in 6 Gy, 192 +/- 264 in 12 Gy and 22 +/- 13 in 18 Gy groups; P < .0002). At 6 weeks, computer-derived histological percent area stenosis was reduced from 26 +/- 10% in the control group to 1 +/- 1.3% in the 18 Gy group (P < .0001), but lower doses had no significant effect. CONCLUSIONS: Administration of intra-arterial beta irradiation with a 90Y source is technically feasible and compatible with an ordinary catheterization laboratory environment. A dose of 18 Gy effectively induces long-term inhibition of neointimal hyperplasia.

Angioplasty, Balloon↗
PubMed1992

[Aminopyrine breath test in hepatic auto-transplantation in pigs].

The aminopyrine breath test (ABT) was performed during hepatic autotransplantation in the pig. The test is reproducible in this animal and only hepatic cytochromes perform the demethylation of aminopyrine. Ischemia, varying from 90 to 200 minutes, generated a major decrease in the elimination of the 14CO2 and a marked change in the elimination curve. In this specific model it was not possible to assess survival of the animal by the ABT.

Aminopyrine↗
PubMed1990

Early assessment of tissue viability with radioiodinated heptadecanoic acid in reperfused canine myocardium: comparison with thallium-201.

Myocardial scintigraphy with heptadecanoic acid labeled with iodine-123 (123I-HDA) may allow early noninvasive delineation of viable myocardium after reperfusion. In this study myocardial uptake of 123I-HDA was compared with that of thallium-201 in six closed-chest dogs after 5 hours of occlusion followed by 1 hour of reperfusion of the left anterior descending coronary artery. Myocardial blood flow was measured with microspheres, and myocardial viability was assessed by means of triphenyltetrazolium chloride staining. In viable areas of the reperfused region, 123I-HDA uptake, thallium-201 uptake, and myocardial blood flow were similar to those measured in the control circumflex region. However, in infarcted areas they were reduced to 48 +/- 2% (mean +/- SEM; p less than 0.001), 59 +/- 3% (p less than 0.001), and 74 +/- 5% (p less than 0.001) of control values, respectively. Results of multiple regression analysis showed that thallium-201 uptake primarily reflected the level of flow during reperfusion, whereas 123I-HDA uptake was dependent on both myocardial blood flow and viability. At each level of flow, 123I-HDA uptake was significantly lower in infarcted than in viable myocardium. By means of discriminant analysis, 123I-HDA uptake was found to be the single most important predictor of viability, whereas thallium-201 was only of limited importance. Myocardial 123I-HDA uptake greater than or equal to 71% or myocardial thallium-201 uptake greater than or equal to 73% best differentiated viable from infarcted myocardium. According to these criteria, 123I-HDA predicted myocardial viability with a sensitivity of 77%, a specificity of 84% and a predictive accuracy of 81%.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

[Trefoil balloon, a new instrument for percutaneous valvuloplasty].

Complete obstruction of blood flow during balloon inflation is a major problem of percutaneous balloon valvuloplasty. To ensure continued transvalvular blood flow the authors have developed the "Trefoil balloon" consisting of three identical angioplasty balloons mounted on a single catheter. The Trefoil balloon was tested in the aorta and aortic valve in 4 dogs and produced a pressure gradient from 5 to 40 mm Hg where conventional balloons were completely occlusive. The Trefoil balloon was then used in 3 children with congenital valvular stenoses (2 pulmonary and 1 aortic stenosis). The immediate results of these valvuloplasties were satisfactory. Continued flow during balloon inflation was documented by right ventricular injection of contrast medium in the cases of pulmonary stenosis and by a systolic aortic pressure of 75 mm Hg during balloon inflation in the case of aortic stenosis. The Trefoil balloon is a promising new device for percutaneous valvuloplasty.

Angioplasty, Balloon↗
PubMed1986

Trefoil balloon for percutaneous valvuloplasty.

A new balloon (Trefoil balloon) was developed to avoid complete interruption of blood flow during percutaneous balloon valvuloplasty. It consists of three identical 2- to 4-cm-long angioplasty balloons mounted in a parallel fashion on a single catheter. Filled simultaneously, they assume the cross section of a rosette, allowing for continued blood flow. Trefoil balloons of various sizes were tested in five dogs (aorta and aortic valve). They created a gradient ranging from 5 to 40 mmHg where conventional, single balloons of comparable size were completely obstructive. In three consecutive patients with congenital pulmonary stenosis, Trefoil balloons were used successfully and without significant complications. Continued transvalvular blood flow during the actual dilatation process was documented in all cases. The Trefoil balloon is a promising new device for percutaneous valvuloplasty and, perhaps, coronary angioplasty.

Adolescent↗
PubMed1980

[New approaches in ECG automatic monitoring in intensive care].

Much of the information to be obtained from the electrocardiogram is hidden in its conventional form of presentation. A study of the first and second differentials of the signal illustrates this point and shows future potential for using this approach in investigative and automated monitoring procedures.

Animals↗