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Biomedical subjects

L Merlin

Publications and source records attributed to L Merlin.

16 recordsLinked to original sources
PubMed1990

Pharmacology and pharmacokinetics of stereoisomers in radiopharmacy.

Nowadays stereochemistry and biologic stereospecificity are involved in the search for new radiopharmaceuticals. This article reviews: 1) The factors involved in selective distribution of stereoisomers: first-pass effect, binding to plasma proteins, enzyme effect and membrane transport; 2) the distinction between pharmacologic specific receptors and acceptor sites; recognition of stereoisomer ligands by specific receptors of opioids, neuroamines, steroids; 3) the ligands labeled with positron emitter radionuclides useful for tomography: dopaminergic, opiate, serotonergic, benzodiazepine ligands and muscarinic ligands; these ligands are labeled with 11C, 18F or 75Br. The balance between the benefit of using a stereoisomer and the burden of sophistication in its chemical preparation is discussed. In conclusion, there is not a clearcut position in favor of a systematic choice of an enantiomer radiopharmaceutical.

Carbon Radioisotopes↗
PubMed1986

[Detection of endotoxins in radiopharmaceutical preparations--I. Comparison of rabbit hyperthermia after intravenous or intrathecal administration of reference endotoxin preparations].

The rise of the rabbit internal temperature after endotoxin injection is related to the route of administration. A rise of 1.71 +/- 0.411 degrees C is obtained after i.v. injection of 1 ng/kg Escherichia coli 0111.B.4 endotoxin. An increase of 1.93 +/- 0.236 degrees C is obtained after suboccipital intrathecal injection of 0.1 ng/kg of the same endotoxin; with the intrathecal route, the hyperthermia is induced by E. coli endotoxin after a dose ten times lower than with i.v. injection as shown by statistical analysis.

Animals↗
PubMed1986

[Detection of endotoxins in radiopharmaceutical preparations--II. Comparison of the sensitivity of methods using the rabbit and the Limulus amoebocyte lysate for the detection of endotoxins].

The rise of the rabbit internal temperature after i.v. injection of an endotoxin solution is proportional to concentration. Gelation of Limulus amoebocyte, when in presence of an endotoxin solution, is also related to concentration. We compared the sensitivity of these two methods. With our experimental procedure, the rabbit is sensitive to a 0.40 ng/mL solution and the Limulus amoebocyte lysate to a 0.14 ng/mL solution. The rabbit sensitivity increase is related to the per kilogramme injected volume, whereas sensitivity is not related to the volume to check in the case of the lysate.

Animals↗
PubMed1986

[Detection of endotoxins in radiopharmaceutical preparations--III. Limulus test assessment using radiopharmaceutical preparations; correlation with the rabbit pyrogen test].

Experiments using 17 radiopharmaceuticals containing known amounts of added endotoxin show that none of them inhibits the pyrogenic reaction of the rabbit. Gelation of the Limulus amoebocyte lysate (LAL) is inhibited by 4 of them: colloidal erbium 169Er citrate, colloidal rhenium 186Re sulfide, colloidal technetium 99mTc (Re) sulfide for liver scintigraphy and the colloidal technetium 99mTc (Re) sulfide for lymphography. This inhibition is cancelled, either by dilution or after neutral pH adjustment. Both controls were performed on 313 batches of various radiopharmaceuticals, 95% of results were identical (93% negative, 2% positive). The remaining 5% correspond to positive LAL tests vs negative rabbit tests on the same batches. No negative LAL test vs positive rabbit test was observed.

Animals↗
PubMed1981

[Results of a survey on the use of 123 iodine for scintigraphic exploration of the thyroid gland (author's transl)].

A survey of thyroid gland scintigraphy with 123 Iodine was carried out on 1131 patients, and data concerning the time of examination as well as indications, scintigrams and uptake measurements are presented. Minimal dosage provides a sufficient counting rate and good quality images and delivers a radioactive dose 15 times lower than with conventional 131 Iodine scintigraphy.

Adolescent↗