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Biomedical subjects

D Comar

Publications and source records attributed to D Comar.

At least 91 records · Page 5Linked to original sources
PubMed1976

Nicotine-11C: synthesis and distribution kinetics in animals.

In order to study "in vivo" the distribution kinetics of (-)-nicotine in animals, this molecule was labeled with carbon-11. Two synthesis methods are described. Immediately after intravenous administration of (-)-nicotine-methyl-11C in rabbits the gamma-camera shows a strong radioactivity build-up in the brain and kidneys. The biological interest of this carbon-11 labeled molecule is discussed.

Animals↗
PubMed1976

Labelling and metabolism of methionine-methyl-11 C.

Carbon 11 which is a 20.4 minutes half life isotope emitting positrons was used for methionine labelling on the methyl group by action of 11C-methyl-iodide on DL or L homocysteine. With the method described, 20 to 30 mCi of 11C-methyl-methionine (Specific activity 50 mCi/muM) may be obtained within 25 minutes. The 20 Mev proton beam used for 11C production was 10 muA. The metabolism of 11C methionine studied on mice shows a high uptake in pancreas and to a smaller extent in brain. On humans sequential images were obtained at the head level which allowed measurement of the uptake of the radio-labelled compound in the brain so as to study the radioactivity curve in different parts of the organ.

Adult↗
PubMed1976

[Effect of an electric field on the penetration of fluorides into dental enamel, studied in vitro and in vivo].

The aim of the present study is to determine the influence of iontophoresis on the deposition of fluorine in dental enamel. A micromethod of fluorine-deposition and of dental enamel-sampling was perfected in vitro; it was then applied in vivo. Fluorine was layed down by topical and iontophoretical way, under the form of sodium fluoride in neutral solution. In in-vitro and in 2 in-vivo asseys 18F was used as an indicator, while in other ones fluorine was titrated by mean of a specific lanthan-fluoride electrode. Results from both methods agree. It is stated that the fluorine deposition on enamel remains lightly but significantly higher, in vivo as well as in vitro, when the tooth is subjected to a continuous electrical field.

Adolescent↗