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Biomedical subjects

D Doucet

Publications and source records attributed to D Doucet.

30 records · Page 2Linked to original sources
PubMed1989

[Secondary reconstruction of the mouth floor using a complete and prepared skin graft after non-interrupted pelvi-mandibulectomy].

A technique of secondary reconstruction of the buccal floor after non interruptive pelvimandibulectomy by thin-split graft enables insertion of a dental prosthesis to assist functional recovery. Results of 46 grafts of this type performed at the Institut Gustave Roussy, Villejuif, France, including 21 cases previously analysed in the Annales d'oto-laryngologie, Paris 1985.

Adult↗
PubMed1989

Hemodynamic and electrophysiologic effects of low osmolar contrast agents during coronary angiography in the dog and the rabbit.

The electrophysiological tolerability of ioxaglate (160 mgI/ml) and iohexol (140 mgI/ml) was assessed in rabbits (n = 12 per group). There was a significant induction of ventricular fibrillation in the group given iohexol. An explanation for this phenomenon could be the lack of sodium in this preparation. Ioxaglate, iopamidol and iohexol (all at 320 mgI/ml) were also compared during coronary angiography in the dog (n = 10) after bolus administration, using the carotid approach (5 and 8 ml-0.5 ml/sec). Each dog received all the compounds in the left coronary artery and selectively in the left anterior descending artery, at random. Four dogs had lethal ventricular fibrillations after iohexol. Iopamidol and iohexol induced significant bradycardia in comparison with saline. A biphasic effect on myocardial contractility was observed with all contrast media: a short-lasting, typical decrease in dP/dt was seen with ioxaglate by the end of injection, while iohexol and iopamidol caused a similar negative inotropic effect in some cases (25%) after increasing dP/dt. The positive inotropic effect was greater with iopamidol and iohexol than with ioxaglate (p less than 0.05). The possible clinical consequences of the lack of sodium in contrast media preparations and of the changes in myocardial function are discussed in the light of the present results.

Animals↗
PubMed1988

Canine acute myocardial infarction. In vivo detection by MRI with gradient echo technique and contribution of Gd-DOTA.

This experimental study was designed to evaluate the sensitivity of MRI in the detection of acute myocardial infarction, determine the utility of fast gradient-echo (GE) imaging and study possible improvements in diagnostic efficacy using a paramagnetic contrast agent (gadolinium-DOTA). Myocardial infarcts were induced in 11 dogs by semidistal embolization and imaged using spin-echo and/or GE pulse sequences, short TRs (250 to 450 ms) and cardiac gating. After the dogs died, the heart was imaged under the same conditions as in vivo. Blind comparisons between precontrast, postcontrast (0.1 mM/kg and 0.5 mM/kg), postmortem images and anatomic findings (triphenyl-tetrazolium-chloride staining) were recorded. This study shows that infarcted areas can be detected on plain MRI images in the form of a hypersignal, probably attributable to increased proton density, with better efficiency of GE compared with spin-echo imaging; injection of gadolinium-DOTA allows better delineation of infarcted areas, especially for 10 minutes after administration.

Animals↗
PubMed1988

Experimental study of DOTA-gadolinium. Pharmacokinetics and pharmacologic properties.

Pharmacokinetic and acute-toxicity studies of Gd-DOTA meglumine (Mgl) were evaluated in various animals and compared with those of Gd-DTPA Mgl. The agents were injected intravenously at two dosages: 0.1 or 0.5 mmol/kg. Various organs and tissues were removed at specified times after injection and assayed for gadolinium (Gd) concentration. The two complexes behave in an identical fashion in their short-term biodistribution and excretion. The very rapid distribution in the body (except in the brain) and the high clearance from blood are due to an extravascular distribution. The small distribution volume and the very high hydrophilicity account for its extracellular localization. There is no accumulation within any organ. Rapid disappearance, short half-life, size, and hydrophilicity of these molecules are in agreement with urinary elimination by free glomerular filtration. Whatever the species or the salt used, Gd-DOTA appears safer in its acute toxicity than Gd-DTPA with an 85% higher safety factor. These results can be explained by the greater stability of Gd-DOTA (very slow kinetics of dissociation and greater specificity of DOTA than DTPA for gadolinium), and the lower osmolality of DOTA than DTPA. The pharmacokinetic characteristics and the very low toxicity of Gd-DOTA Mgl may prove its suitability for intravenous or oral administration in humans.

Animals↗
PubMed1982

[Lyophilization protection of hemoglobin by N-acetyltryptophan].

Measurements of methemoglobin content, different oxyphoric powers, oxygen affinity were made on freeze-dryed hemoglobin without protector and in presence of N-acetyl tryptophan and/or alpha-D glucose. These measurements revealed that, at low concentrations, N-acetyl tryptophan offers a better protection than glucose. Moreover, this acetylated amino-acid decreases the oxygen affinity of hemoglobin (Po(2)50 increased). The two protectors do not seem to compete, but present complementary effects.

Biological Transport↗