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Biomedical subjects

G Meyniel

Publications and source records attributed to G Meyniel.

At least 37 records · Page 2Linked to original sources
PubMed1984

[Early diagnosis of postinfarction ventricular aneurysm. Value of contrast scintigraphy].

Early diagnosis of a ventricular aneurysm after myocardial infarction may provide a valuable means of preventing certain complications. We studied 55 patients with acute myocardial infarction on the 8th day by Technetium 99 angioscintigraphy with study of wall motion and ejection fraction at equilibrium. The results were compared with left ventriculography performed three months after infarction. Angioscintigraphy demonstrated 17 cases of dyskinesia, 16 cases of hypokinesia, and 22 cases of akinesia, divided into two subgroups depending on whether the ejection fraction was lower (n = 11) or higher than 40% (n = 11). Contrast angiography at 3 months confirmed the presence of 27 aneurysms, 17 akinetic plaques and 11 cases of hypokinesia. Comparison between the two series of investigations showed excellent correlations: in the group of dyskinesia (17 cases) an aneurysm was confirmed in 15 cases; in the group of hypokinesia (16 cases) only one aneurysm was demonstrated by the reference angiography. The results were less uniform in the group with akinesia. In the subgroup with a low ejection fraction, 9 out of 11 cases progressed to aneurysm and, in retrospect, should be considered as likely aneurysms. There were only 2 aneurysms (2/11) in the subgroup with localised akinesia and a high ejection fraction. The overall results suggest that angioscintigraphy at the 8th day of myocardial infarction is a reliable means of detecting left ventricular aneurysm; in cases of dyskinesia or widespread akinesia with an ejection fraction of less than 40% the presence of an aneurysm was confirmed in 24 out of 28 patients (86%).(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1983

Feasibility of gated single-photon emission transaxial tomography of the cardiac blood pool.

A procedure for gated single-photon emission transaxial tomography of the cardiac blood pool using a commercially available rotating camera and a computer is described. During image acquisition, the end-diastolic and end-systolic frames are retained after each of the 16 angular steps of the rotation of the camera around the anterior side of the patient's chest. Complete acquisition takes 25 minutes; 10 more minutes are required for the reconstruction and processing of the sections. One set of images is oriented transaxially; the other set includes vertical sections obtained by rotation around a vertical axis passing through the center of the left ventricular cavity. Results from the planar and tomographic examinations were in good agreement for most of the 18 patients who underwent both studies, although more inferior abnormalities were detected with tomography.

Coronary Circulation↗
PubMed1983

Study of cell changes induced by radiolabelling of human lymphocytes with 99m-technetium.

With the aim of evaluating cell changes possibly induced by labelling lymphocytes with 99m-technetium (99mTc), several rosette tests and stimulation assays with mitogens have been carried out before and after radiolabelling. The results presented here show that (i) as the rosette tests are not modified statistically, the original labelling method does not seem to induce short term membrane structure modification and (ii) as stimulation by mitogens decreases after labelling with 99mTc, medium term radiation damage, linked to autoirradiation of the cells, can be evoked. This study indicates that there is reason to limit the time taken to perform scintigraphic explorations with labelled lymphocytes in man.

Cell Survival↗
PubMed1982

Labeling of human lymphocytes with 99mTc by means of stannous pyrophosphate. Scintigraphic applications.

An original 99mTc-labeling method applied to human lymphocytes is described. This technique is based on the use of stannous pyrophosphate to reduce sodium pertechnetate. The proposed procedure has two main advantages: firstly, the labeling process takes place in a neutral and buffered medium which prevents any cellular aggregation; secondly, the labeling yield obtained is compatible with scintigraphic studies in man. The influence of each parameter on the labeling quality had been studied as well as the binding stability of the technetium fixed on cells. A systematic study of lymphocyte surface markers, before and after labeling, has led to the suggestion that the labeling process seems to affect cellular membranes, probably because of the technetium binding. Finally, scintigraphic results are presented, the study being performed on eight healthy volunteers. These results are compared with those published by other authors who used either a different radioisotope or a different labeling method.

Humans↗
PubMed1982

Metabolism of adiphenine. II. Identification of major excretion metabolites in rats.

1. Major metabolites isolated from rat urine after administration of a single dose of [14C]adiphenine or [3H]adiphenine were identified by chromatography and n.m.r. spectrometry, and by comparison with authentic reference compounds chemically synthesized. 2. Adiphenine was extensively metabolized by hydrolysis of the ester bond into diethylaminoethanol, diphenylacetic acid, diphenylacetic acid glucuronide and, in small quantities, the corresponding glycine and glutamine conjugates.

Animals↗
PubMed1982

A comparison between conventional scintigraphy and emission tomography with thallium-201 in the detection of myocardial infarction: concise communication.

We have compared emission tomography and conventional scintigraphy with thallium-201 in a series including 15 normal subjects and 64 patients showing transmural myocardial necrosis in various locations, fully documented by clinical, electrocardiographic, and enzymatic evidence. The reconstruction was derived from 32 projection images collected around the left side of the patient's chest by a rotating scintillation camera. The conventional views and the transverse, frontal, and sagittal sections were interpreted independently by two observers. The final calculated sensitivity was 89% with conventional scintigraphy and 98% with emission tomography, and the specificity was 93% in the two cases. Thus, emission tomography provides a better sensitivity and also a better interobserver agreement than conventional scintigraphy in the detection of transmural myocardial necrosis with thallium-201.

Humans↗
PubMed1981

Automatic construction of pulmonary functional images.

Dynamic study of regional ventilation of Xenon-133 with a gamma camera requires the medical interpretation of many analog scintigraphic images and time-consuming curve analysis. We have developed a program for the immediate creation of two functionally digitalized images by minicomputer which collects the data from the whole study. These images are constructed by assigning a value to each pont which depends upon the dynamic phenomenon. The program automatically computes the working files of the dynamic acquisition, performs the background subtraction, and delineates the boundaries of the lungs using isoactivity lines. Then the functional images of transit time and clearance of the radioactive gas in the alveoli are reconstructed. This processing takes less than 1 min and allows both time sharing and enhancement of interpretation.

Computers↗
PubMed1981

Myocardial emission tomography with thallium-201. Value of multiple and orthogonal sections in the study of the myocardial infarction.

The usefulness of transverse, sagittal, and frontal tomographic images was assessed in the study of the myocardium labelled with thallium-201. In a series of 20 patients with myocardial infarcts in various locations documented by clinical, electrocardiographical, and biochemical data in 15 cases and uncertain diagnosis in 5 cases, the sections reconstructed from 32 views obtained with a rotating scintillation camera were compared to the conventional views. Quantitatively, the mean myocardium-to-background activity ratio improved significantly from 1.60 to 2.57 (p less than 0.001); qualitatively, the presence, site, and size of the defect were more easily determined on the sections and generally showed a sharp contrast to the normal tissue; transverse sections enabled us to explore the anterior infarcts, but sagittal or frontal views were required for inferior locations. The tomographic exploration was normal in only patient whose diagnosis was uncertain. These results suggest that three-dimensional emission tomography can improve both detection and quantification of the myocardial infarct.

Humans↗
PubMed1981

Metabolism of adiphenine. I. Absorption, distribution and excretion in rats and mice.

1. The disposition of adiphenine labelled with 14C in two positions has been investigated in rats and mice after i.v. administration, and has been compared with that of the [14C]diethylethanolamine HCl and of the [14C]diphenylacetic acid. 2. Radioactivity in the blood declined in a biphasic manner. Biliary elimination depended upon the 14C-labelled compound administered: less than 5% dose for the diethylethanolamine moiety, 100% dose for the carboxylic moiety. Of the radioactivity appearing in rat bile, less than 1% is associated with unchanged adiphenine. 3. In preliminary metabolic studies, three major metabolites have been identified: diphenylacetic acid, diethylethanolamine and a diphenylacetic acid glucuronide. 4. Uptake by the brain of [14C]adiphenine shortly after dosing is 15 times greater than that of blood. Radioactivity is also found in the hypophysis, the adrenals and melanoid pigments, with a concn. up to 30 times greater than that found in the blood.

Absorption↗
PubMed1981

Labelled dyes, a new 125I-indomonocarbocyanine and 125I-BSP, in the exploration of experimental cholestasis and steatosis in the rat.

A new dye, an indomonocarbocyanine labelled with radioactive iodine, was studied in normal rats and in rats with experimental diseases. After i.v. injection, the cyanine was selectively concentrated in the liver and eliminated in the bile; urinary excretion was found to be minimal but increased in rats with ligated bile duct. In addition, the blood clearance kinetics of the labelled dyes were significantly modified in cases of hepatic cholestasis or steatosis. A comparative study was carried out with 125I-BSP; the results showed that these 2 dyes may be considered as complementary in the exploration of liver function.

Animals↗
PubMed1980

Comparative physico-chemical properties, biological effects, and disposition in mice of four nitrogen mustards.

Chlorambucil, phenyl acetic mustard, melphalan and mitoclomine are aromatic nitrogen mustard derivatives. These drugs show a fairly wide range of chemical reactivity and lipophilicity. In the series presently investigated, the more hydrophilic compounds (melphalan and phenyl acetic mustard) are the more toxic to mice and also the more active against Moloney sarcoma implanted IP in mice. No clear relation could be shown between the alkylating activity and the biological efficiency. All the compounds induce changes in DNA synthesis with differences between the timing of alterations and recovery. Nevertheless, return to pretreatment levels of thymidine incorporation is more rapid in the bone marrow and intestinal mucosa following administration of the drugs, than in tumor cells. The 14C-ethyl labeled compounds was used to investigate the part of the carrying structure in their disposition in mice.

1-Naphthylamine↗
PubMed1980

Disposition in rats and mice of chloropractolol, a new beta-blocking agent.

1. The disposition of a new beta-blocking agent, chloropractolol, labelled with 14C and with 3H, has been studied in rats and mice. 2. After i.v. administration to the rat (25 mg/kg) of a mixture of [14C]- and [3H]chloropractolol, urinary and faecal excretion, biliary elimination and tissue distribution were similar for the two labelled species. However, 3% of the dose was recovered as 14CO2. 3. Chloropractolol and/or metabolites did not show high cardioselectivity. Uptake by heart of the two labelled species was very close to that found for [14C]practolol and [14C]propranolol. 4. Preliminary metabolic studies using h.p.l.c. have shown that in the rat chloropractolol is extensively metabolized, which contrasts with the more limited metabolism of practolol in the same species. Deacetylation is a minor route of metabolism. A structure for the main urinary metabolite is suggested.

Adrenergic beta-Antagonists↗