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Biomedical subjects

L Pourcelot

Publications and source records attributed to L Pourcelot.

At least 127 records · Page 7Linked to original sources
PubMed1984

Meta-iodobenzylguanidine adrenal medulla localization: autoradiographic and pharmacologic studies.

In order to investigate the mechanism of uptake of meta-iodobenzylguanidine (mIBG) by the adrenal glands, autoradiographic and pharmacologic studies were performed in mice and dogs receiving radioiodinated mIBG. In mice, on macroautoradiography of whole body sections 48 h after 125I-mIBG, most of the radioactivity was focused in the adrenal glands. On microautoradiography, silver grains were exclusively located in the adrenal medulla. Tissue counting after phenoxybenzamine, cocaine, and desipramine treatment resulted in 45%, 35%, and 0% inhibition of mIBG uptake, respectively. Tissue counting and scintigraphic studies demonstrated a more than 50% mIBG release from the adrenal glands after reserpine. These data indicate the high affinity of mIBG for adrenal medulla and suggest that the mIBG and catecholamine uptake mechanisms are only partially the same.

3-Iodobenzylguanidine↗
PubMed1984

[Echotomography and spectral analysis of the Doppler signal in the assessment of carotid lesions].

Real-time echography and C.W. Doppler examination with spectrum analysis are the two methods most widely used for the study of the circulation. Echography allows the detection and the localization of the atheromatous defects whereas Doppler examination provides information on the blood flow. With the help of the frequency analysis of the Doppler signal it is possible to study much more accurately the local haemodynamic conditions. Spectrum analysis is one of the possible display mode for the Doppler signal. It provides in comparison with the zero crossing mode, much more haemodynamic parameters on the blood flow, such as velocity spectrum, density of red cells on each velocity... In this study, we tried to demonstrate that a relationship exists between the amplitude of the spectrum disturbances, recorded just after a stenosis and the degree of this stenosis. For that we propose a classification of the spectrum disturbances in five grades, each of them being related to an interval of possible values for the stenosis degree (grade I----stenosis less than 40% in area, grade II----40-60% stenosis, grade III----60-75% stenosis (extended defects) grade IV----70-90% (extended defects) and 60-90% short stenosis. Grade V: stenosis greater than 90%. The results provided by this classification were compared to those obtained by measurements of the stenosis degree on the piece of endarterectomy (72 cases). The results were in agreement in 94% of the cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Arteriosclerosis↗
PubMed1984

[Transcutaneous measurement of blood flow in arteriovenous fistulae caused by hemodialysis using Doppler ultrasound].

Blood flow measurement in arterio-venous fistulae can be performed with a duplex ultrasound system which combines echography and C. W. Doppler. This method is very useful to follow up the patency of the fistulae and his consequence on the cardiac function. The exploration consists in two steps: a qualitative study of the Doppler spectrum to detect a possible decrease of the arterial diastole flow which traduce a severe stenosis; the evaluation of the blood flow in ml/min. The blood flow in ml/mn is a good parameter for the follow-up of the fistulae; moreover in case of high blood flow values, it is very useful to guide the surgical therapy.

Arteriovenous Shunt, Surgical↗
PubMed1984

[Ultrasound in the study of fetoplacental circulation].

Exploration of fetal vessels is performed with a duplex system which combines a real-time linear imaging system 3.5 MHz and a pulsed Doppler (2.5 MHz). The transducers of the imaging and Doppler systems are associated in the same probe. Umbilical and aortic circulation have been investigated on 100 pregnancies. The umbilical artery Doppler spectrum shows an important diastolic flow which increases all along the pregnancy. A decrease of this flow occurs when the placental circulatory resistances increase. In case of severe hypertension one can note a decrease or the disappearance of the diastolic flow related to the existence of vascular placental defects (infarctus). This was observed in pathological pregnancies with hypotrophy or fetal death. The placental resistances can be quantified with the Pourcelot index R = A - D divided by A, where A is the maximum systolic amplitude and D the maximum end diastolic amplitude, both measured on the umbilical artery spectrum. Fetal blood flow measurements were performed with the same device. The mean value of the blood flow is about 170 ml/min/kg in the aorta and 120 ml/min/kg in the umbilical arteries at the end of the pregnancy. The possibility to record simultaneously fetal aorta and inferior vena cava enable us to detect abnormal heart rate such as the atrioventricular block.

Aorta↗
PubMed1984

[Imaging medullary cancer of the thyroid].

Based on experience of the last decade including 18 patients, the imaging procedures of medullary thyroïd carcinoma are reviewed. Ultrasonography of the neck is the most contributive for the locoregional expertise, in the preoperative period. All of the classical imaging procedures are useful in looking for the metastasis: namely bone scintiscan, liver ultrasonography, computerized tomography of the mediastinum. Associated parathyroid adenoma and pheochromocytoma are visualized respectively by technetium thallium subtraction scan and meta-iodobenzylguanidine scintigraphy. In the near future, immunoscintigraphy of calcitonin secreting tumors will be developed.

Adolescent↗
PubMed1984

[Validation of quantitative and qualitative data of real-time carotid echotomography in comparison with standard Doppler tests, arteriography and anatomopathology. On 59 carotid endarterectomies].

Findings on ultrasound, arteriography and pathology examinations were compared in 49 patients undergoing 59 carotid endarterectomies between December 1981 and April 1983. Carotid artery lesions were investigated routinely by cervical Doppler, high resolution rapid ultrasound and either direct or more usually venous arteriography (with photographic subtractions). Postoperative endarterectomy specimens were examined to determine the exact degree of stenosis, and also qualitatively (gross pathology and histology of ulcerations and thromboses, the biochemical nature of the plaques, etc.). With respect to detection, that is demonstration of the existence or not of an atheromatous lesion, the ultrasonographic findings could always (100% of cases) be correlated with pathology data. Qualitative analysis of atheromatous lesions showed certain to be diagnosed with ease: calcified, fibrous or chondroid and lipidic plaques, while those complicated by hemorrhage, ulceration or mural thrombosis were less constantly diagnosed by ultrasound imaging. Occlusive plaques were easily detected, while recent intraluminal thrombosis was more difficult to diagnose by ultrasound alone. In this case the combined use of Doppler is a valuable aid, and is a routine procedure, in fact, in the department. Results of quantitative analysis showed good correlation between ultrasound and pathology findings in 79.7% of cases (insufficient in 20.3%). However, if ultrasonography is combined with other ultrasound methods of examination (standard Doppler and spectral analysis of Doppler) correlation is of the order of 95%, close to morphological data supplied by arteriography, with in addition a functional and qualitative approach not possible with arteriography alone.

Aged↗
PubMed1984

[Possibility of a method for dynamic study of abdominal viscera contractility from echographic images. 1st results].

Brilliance variations in selected areas of echographic display are recorded in real time thanks to photoconductive integrations from the screen. The areas concerned are: 1) gastroduodenal or colonic wall; 2) intraluminal medium in the same portion of the digestive tract. Simultaneously the pneumogram is recorded with these photometric variations in long period of time (1/2 h-2 h). Visceral displacements or medium echographic modulations give us informations about motricity and hydraulic changes. Several components of frequency are shown: pulse, respiratory interactions and several components of parietal contractions; we can notice the concordance between frequency variations obtained with others technics such as electrosplanchnography or manometry. This possibility of atraumatic confrontations with a visual control allows us new perspectives in physiopathological studies concerning hemodynamic, biomechanic interactions between viscera.

Abdomen↗
PubMed1984

[Evaluation of the degree of carotid stenosis by spectral analysis of the Doppler signal. Comparison of the results of spectral analysis, angiography and anatomo-pathology].

With the single Doppler spectrum analysis, one can appreciate the degree of the carotid stenosis according to the importance of the haemodynamic disturbances induced by the stenosis. The purpose of our study is to show the possibilities and the limitations of this method. Spectrum disturbances were classified in 5 grades, each of them being related to the importance of the stenosis. The degree of stenosis has been evaluated by the C.W. Doppler spectrum analysis, the angiographies and the anatomical study of the endarteriectomies. We considered that we had a perfect concordance between the results of the different methods when the degree of stenosis measured on the angiographies or on the endarteriectomies was compatible with the spectrum analysis classification: grade I: stenosis inferior to 40% (in area), 23% (in diameter); grade II: stenosis ranging between 40 and 60% in area (23 and 40 in diameter); grade III: stenosis of 60 to 75% in area (40 to 50% in diameter) and of particular shape (extended plaque); grade IV: stenosis ranging between 60 and 90% in area (40 to 70% in diameter); grade V: stenosis higher than 90% in area (70% in diameter). The confrontation of spectrum analysis and angiographic date concerns 58 bifurcations. We got a perfect correlation in 93% of the cases. The confrontation of the spectrum analysis method and the anatomical study of the endarteriectomies concerns 38 bifurcations. We got a perfect correlation in 92% of the cases. The appreciation of the carotid stenosis degree is now performed in routine at the Hospital. For some patients, the endarteriectomy has been decided from the clinical and the spectrum analysis data, and an electro-encephalogram with compression. However these date are generally completed with an angiography with venous punction.

Carotid Arteries↗
PubMed1983

[Study of fetal and placental circulation by ultrasound. New technic in the surveillance of pregnancy].

Echotomography has been used for several years in routine for pregnancy follow-up. The morphological parameters provided by this technique (biparietal diameter, transversal abdominal diameter, length of the limbs...) give an objective information on the foetal growth. The exploration of foetal and placental circulation by Doppler measurement has been used in the past for the detection of the foetal cardiac rythm. The association of Doppler and echotomography allows to know precisely the location of vessels of interest, to quantify blood flow volume transcutaneously, and to determine an index of placental resistance. Recent improvements have simplified the use of this complex technique. Transducers for Doppler and imaging have been placed in the same probe very easy to handle. This system allows a precise localization of Doppler sample volume within the vessel to be explored. The great vessels can be studied all long the pregnancy. Normal Doppler spectrum of umbilical arteries shows an important diastolic flow. This fact is related to the low circulatory resistance of the placenta. When the placental circulatory resistances increase (because of placental infarcts for instance) the diastolic flow decreases in the umbilical arteries. To quantify this modification of umbilical circulation we used an index of the resistance (Pourcelot index) [9]: R = (formula; see text) [A systolic amplitude; D diastolic amplitude]. In normal cases, values of R decrease progressively during the course of the pregnancy. In case of abnormal pregnancies (dysgravidy) the index increases. Abnormal values of R had been correlated with hypotrophy or foetus death. With this duplex system it is also possible to determine the different parameters which are necessary to quantify the foetal blood flow in ml/mn. The first results obtained in dysgravidies confirm the major interest of blood flow study in follow-up and prognosis of high risk pregnancies.

Adult↗
PubMed1982

[The detection of deep venous thrombosis by fibrinogen labelled with iodine 125. Specificity and sensibility in comparison with standard phlebography (author's transl)].

During the last 6 years, more than 4,000 tests using 125I fibrinogen have been performed on orthopedic and traumatic patients who were undergoing a thromboembolic treatment by means of subcutaneous heparin. The high accuracy of this method has been confirmed using phlebography. This test still remains a simple, faithful, and non traumatic diagnosis tool in the early detection of thrombosis of the limbs of patients undergoing traumatologic and orthopedic surgery. Moreover, the labeled fibrinogen test is useful in the determination of the efficiency of antithrombotic preventive therapy.

Diagnosis, Differential↗
PubMed1981

[Ultrasound determination of the foetal sex (author's transl)].

Determination of the foetal sex in utero by ultrasonography is possible after the sixth month of pregnancy. In 100 women examined during the last trimester (15 with breech presentation and 85 with cephalic presentation) the sex of 28 boys and 34 girls could be diagnosed. This represents 72,9% positive determinations, if breech presentations are excluded. The best results are in fact obtained in cephalic presentations. One cause of error is spina bifida, which might give images resembling the scrotum (one case in our study). This examination is of interest mainly in cases of sex chromosome abnormalities.

Female↗
PubMed1980

[The investigation of pancreatic pathology by "grey range" echotomography. Study of 80 cases (author's transl)].

Over an 18-month period, the authors studied 305 cases of patients with or suspected of having pancreatic disease. Although atraumatic and free of danger, it must be borne in mind that echotomography is hampered by the air and water barrier of the hollow organs of the intestines since 20% of subjects cannot be explored. Well defined full or empty pancreatic tumours and acute inflammatory syndromes have well defined echographic appearances. In cases of chronic pancreatitis or poorly defined tumours the diagnosis is more difficult and ultrasound examination often only provides an additional element in a clinical argument. The great reliability of this examination should lead to its use at the beginning of investigations, with the possibility of the result orienting the clinician towards less harmless examinations.

Diagnostic Errors↗
PubMed1980

[Carotid artery investigation by real time ultrasonic imaging (author's transl)].

Ultrasonography examination enables vascular lesions in the main cervical arteries to be relatively easily recognized in patients with hemodynamic disturbances, but these changes are no longer present when the vascular anomalies are not functional. A non-invasive method for detailed visualization of the carotid axis was developed, by the use of rapid continuous ultrasonography. This can reveal the presence of unsuspected atheromatous plaques during the stage when prevention is still possible, and can complement certain investigations of doubtful value that had suggested that atheromatous plaques existed.

Carotid Artery Diseases↗