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Biomedical subjects

J C Besnard

Publications and source records attributed to J C Besnard.

At least 73 records · Page 4Linked to original sources
PubMed1986

[Iodo carboxamidino-1 phenyl-4 piperazine, a new adrenomedullary imaging agent: comparison with metaiodobenzylguanidine].

This report describes the comparison between two adrenal medulla imaging agents, mIBG and I-CPP. Biodistribution demonstrated an early and preferential uptake by both adrenal glands and heart and then storage in the adrenal gland of both agents, however I-CPP is less stable in vivo than mIBG. Reserpine depletion study in rat indicated that the I-CPP and mIBG uptake mechanisms are not similar.

3-Iodobenzylguanidine↗
PubMed1985

Medullary-thyroid-carcinoma imaging in an animal model: use of radiolabeled anticalcitonin F(ab')2 and meta-iodobenzylguanidine.

Radiolabeled anti-calcitonin (CT) immunoglobulin fragments (131I-anti-CT F(ab')2) and meta-iodobenzylguanidine (131I-mIBG) were injected into nude mice with a transplanted medullary thyroid carcinoma (MCT). 131I-Anti-CT F(ab')2 proved to be unsuitable for MCT scintigraphic imaging. However, a high mIBG uptake was observed in MCTs, but not in control tumors (mesothelioma). The uptake of mIBG was not modified by the presence of reserpine or pentagastrine. These results are discussed, and it is suggested that mIBG could be an APUD-system marker.

3-Iodobenzylguanidine↗
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

[Plasma calcitonin and breast tumors].

In order to evaluate the frequency of elevated circulating calcitonin in patients with bone metastasis plasma calcitonin level was measured in 32 patients with breast carcinoma with and without bone metastasis. Calcitonin was found in normal ranges in all patients without metastasis. In patients with bone metastasis, 4 had normal level, 2 were found with elevated calcitonin. Our results suggest that elevated calcitonin is related to the presence of bone metastasis but is not a constant finding in these patients.

Adult↗
PubMed1983

Immunocytological study of the distribution of C-cells calcitonin in the thyroid gland of the normal adult gerbil.

The distribution of C-cells in the thyroid gland of the gerbil (Meriones inguiculatus) was studied on serial sections in the cranio-caudal direction. C-cells were visualized by immunofluorescence with an anti-calcitonin immune serum. A very heterogeneous distribution was found. C-cells first appear in the posterio-interior position. Then they progressively occupy the whole posterior part and finally are confined to the posterio-exterior position. No C-cells at all were detected in the upper and lower poles. According to the species, there is a wide variation in the relative distribution of C-cells in the thyroid gland. Our results add to the information available about the distribution of C-cells and its bearing on phylogenic evolution.

Animals↗
PubMed1982

Falsely elevated results of radioimmunoassays using double antibody method: arguments for a third anti-rabbit IgG antibody present in certain human sera.

Nine sera with falsely elevated results in a TSH radioimmunoassay were studied. Sera dilution and gel filtration showed that the immunoreactive TSH was different from the standard and labeled TSH. It coeluted with the immunoglobulin fraction of the serum. Rabbit serum decreased or emphasized the artifact according to the dose. Falsely elevated results appeared only in radioimmunoassays using a double antibody method for the separation of free and bound labeled hormone. FSH, LH, and beta HCG radioimmunoassays using the double antibody method underwent the same disturbance as the TSH assay in these patients. Our results suggest that the artifact may be due to the presence in certain human sera of anti-rabbit IgG antibodies, interfering in the radioimmunoassay by inhibition of the binding of first and second antibodies.

Adult↗
PubMed1981

Choroid plexus localization of 99mTc-pertechnetate.

Autoradiograms were performed on brain slices, 3 h after 99mTc-pertechnetate injection, and 24 h after previous treatment with stannous pyrophosphate. On macroautoradiograms, the radioactivity was focused entirely upon plexus areas. Silver grains were predominantly overlying the cytosol of brush border cells; less than 10% of the total plexus radioactivity was found in vascular structures. These findings suggest that a possible metabolic phenomenon exists rather than a passive distribution.

Animals↗
PubMed1980

Bone kinetics of calcium-45 and pyrophosphate labeled with technetium-96: an autoradiographic evaluation.

The uptake of calcium-45 and of pyrophosphate labeled with the long-lived technetium-96 isotope were compared by means of liquid-emulsion microautoradiograms of the epiphyseal plates of 10-week-old rabbits, at 30 min, and 3 and 48 hr after i.v. administration. For both tracers, thin sections confirm the significant role of the blood supply, especially shortly after injection. However, other more specific mechanisms lead to a mixing of the calcium in the mineral mass and to a linear deposition of technetium facing the osteoid surfaces. These findings suggest that the tropism of tin-reduced technetium pyrophosphate is not governed by the mineral pool but rather by exchanges inside a still poorly calcified organic matrix.

Animals↗
PubMed1978

Correlation of free thyroxine index and thyroxine: thyroxine-binding globulin ratio with the free thyroxine concentration as measured by the thyroxine and thyroxine-binding globulin radioimmunoassays.

The concentration of thyroxine-binding globulin in the serum can now be measured by a simple and specific radioimmunoassay. Triiodothyronine uptake and measurement of total thyroxine have been combined to yield a free thyroxine index which has been found to correlate with the clinical state of the patients. An estimate of the free thyroxine concentration, as measured by the thyroxine and thyroxine-binding globulin radioimmunoassays, provided a good correlation with the free thyroxine index and the thyroxine: thyroxine-binding globulin ratio. However, the thyroxine: thyroxine-binding globulin ratio is inaccurate when thyroxine-binding globulin concentrations are high or low.

Adult↗
PubMed1978

Skeletal uptake of pyrophosphate labeled with technetium-95m and technetium-96, as evaluated by autoradiography.

For animal experimentation, the 95m and 96 technetium isotopes offer many advantages over technetium-99m. Their long physical half-lives and the emission of extranuclear electrons of low penetrating power make it possible to obtain autoradiograms of a great precision. The uptake of technetium stannous pyrophosphate by the epiphyseal plate was studied using liquid-emulsion microautoradiography, 3 hr after i.v. injection into 10-week-old rabbits. Microautoradiograms showed a well-defined and rather specific pattern of localization with intense uptake beneath the epiphyseal disk on the extremities of the vascular buds and a lack of accumulation in the cartilage, whether calcified or uncalcified. In the metaphysis, the label was located where new bone was being laid down and also over the cytoplasm of osteoclasts. We deduce from these results that in normal bone the general distribution of this tracer reflects mainly the arrangement of the blood supply, but the specific sites of accumulation are the bone-forming surfaces and the active resorbing osteoclasts.

Animals↗
PubMed1977

[Radioimmunoassay of serum thyroxin-binding-globulin in euthryoid subjects].

The authors have set up a thyroxine-binding-globulin radio-immunoassay in blood serum. The standard used has been determined by gravimetry, its maximal thyroxine-binding capacity is 0,96 mole of thyroxine per mole of TBG. Serum concentration of TBG has been measured in 159 euthyroid normals. The mean value of the concentration is 20 mg/l.

Antibody Specificity↗
PubMed1977

[Metabolism of alpha macroglobulins of rabbits: study of their half-life].

Rabbit alpha-1-M and alpha-2-M labelling was carried out in vitro with 131I and in vivo with 75-Seleno-methionine in order to determine the half-life of these proteins. alpha-2-M catabolism is faster than the alpha-1-M one. This result is the same when these proteins were obtained from a plasma of a rabbit exhibiting an inflammatory reaction though their half life was shorter.

Animals↗
PubMed1976

[Diagnosis of cerebrovascular disorders using stannous technetium pyrophosphate].

A total of 122 cases of various neurological diagnoses (among which 72 cerebral infarcts, 7 intracerebral hematomas and 38 intracranial tumors) had two separate brain scans, performed within 48 hours of each other after the administration of pertechnetate and technetium stannous pyrophosphate. The comparison of the resulting seans indicates that, in addition of an osseous accumulation, the pyrophosphate localizes greatly in ischemic cerebral lesions, especially those observed during the second week of evolution. It seems that the uptake of pyrophosphate reflects the area of anaerobic changes whereas the accumulation of pertechnetate depends on the disruption of the blood brain barrier. The scintigraphic diagnostic of cerebral infarctions is greatly improved.

Brain Neoplasms↗
PubMed1976

[Alpha-1-antitrypsin, orosomucoid, transferrin and alpha fetoprotein in the amniotic fluid, Changes in concentration in normal and pathologic pregnancies].

In this article, which is a preliminary report, the authors determined amniotic fluid levels of alpha-I-antitrypsin, orosomucoid, transferrin and alpha-fetoprotein during complicated pregnancies with gestational ages of 31 to 42 weeks. These levels were compared with those observed during normal pregnancies. The clinical value of the variations of the glycoprotein levels is discussed.

Amniotic Fluid↗