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Biomedical subjects

M Lemaire

Publications and source records attributed to M Lemaire.

16 recordsLinked to original sources
PubMed1992

From somatostatin to sandostatin: pharmacodynamics and pharmacokinetics.

Somatostatin (SRIF) and its octapeptide analogue, octreotide (Sandostatin), have a similar high affinity for specific receptors with 50% inhibitory concentrations (IC50s) in the subnanomolar range. Hence, the striking superiority of octreotide in vivo, which includes duration of action, specificity, and potency, must originate from its different distribution, metabolism, and excretion behavior. In animals and humans, investigations of their pharmacodynamic/pharmacokinetic relationship show plasma levels of 0.2 to 0.5 ng/mL (approximately 0.3 nmol/L) to be therapeutically relevant for both peptides. The much lower clearance rates and improved metabolic stability in the circulation and in target organs of octreotide, compared with SRIF, result in much longer-lasting, therapeutically relevant plasma and tissue levels and therefore in a longer duration of action. Their apparently specific inhibitory action on growth hormone when compared with that on insulin is pharmacodynamically based, and may be exaggerated by physiological mechanisms of carbohydrate regulation. In summary, there is a distinct relationship between the pharmacokinetic profiles and pharmacodynamic behavior of SRIF and its analogue. Sandostatin.

Animals↗
PubMed1992

Protection against aspirin-induced gastric lesions by lansoprazole: simultaneous evaluation of functional and morphologic responses.

The protective effect of lansoprazole, a new proton pump inhibitor, against aspirin-induced gastric lesions was studied in a double-blind crossover trial with a simultaneous measure of the functional capacities of the mucosal barrier (by a recording of the gastric potential difference) and of the morphologic changes in the mucosa (by gastric endoscopy). After 1 week of treatment with lansoprazole (30 mg per day) or placebo, each healthy volunteer received 1 gm aspirin by mouth. Recording of the gastric potential difference lasted for 3 hours and was followed by gastric endoscopy. Morphologic lesions induced by aspirin were effectively prevented by lansoprazole: Lanza score was 0.67 +/- 0.98 (mean +/- SD) versus 2.25 +/- 1.1 with placebo (p < 0.005, ANOVA). Conversely, the decrease in the gastric potential difference was similar. The inhibition of acid secretion induced by lansoprazole was therefore sufficient to prevent aspirin-induced mucosal lesions without reinforcing the defense capacities of the mucosa. This simple pharmacologic model makes it possible to simultaneously evaluate the functional and morphologic effects of aspirin intake on the gastric mucosa.

2-Pyridinylmethylsulfinylbenzimidazoles↗
PubMed1992

Evidence for an endogenous cholecystokininergic balance in social memory.

The cholecystokinin (CCK) peptide family is involved in a variety of physiological processes, including neurotransmission in the brain. Pharmacological responses to CCK are mediated through at least two receptor subtypes termed CCK-A and CCK-B. Studies with CCK agonists suggest a possible role for CCK in cognition. Using selective antagonists and a behavioural recognition test based on the olfactory discriminative capacities of rats, we found that endogenous CCK acting at CCK-A and CCK-B receptors modulates olfactory recognition positively and negatively, respectively. CCK-B receptor antagonists therefore have facilitatory potentialities on memory processes.

Animals↗
PubMed1992

[Neoadjuvant chemotherapy, with mitoxantrone, cyclophosphamide and fluorouracil, in operable breast cancer of intermediate stage: first results of a phase II study in 40 patients].

Forty patients with intermediate stage (T2 > 3 cm-T3, N0-N1) operable breast cancer received neoadjuvant chemotherapy by MCF (mitoxantrone, cyclophosphamide, 5-fluorouracil). Four cycles were administered at 3-week intervals. The obvious hematological toxicity (64% of grade III for the leucocytes and up to 34% of grade IV for the granulocytes) was rapidly reversible and did not hinder completion of the treatment. Ten patients showed a complete remission and a tumor volume regression of more than 50% was observed in 12 other patients. Tumor shrinkage allowed breast-saving surgery in 50% of the cases. A complete sterilisation of the surgical specimen was found in only two of the 40 patients and a few persisting neoplastic cells were found in ten other cases. A positive response at the level of the axillary lymph nodes was also obtained in more than 50% of the cases. In 25 of the 36 cases examined, the primary chemotherapy induced cellular lesions (fibrosis, necrosis) at the tumor level. A feasibility study was undertaken in order to determine quantitatively several biochemical parameters (steroid hormone receptors, cathepsin D, c-erbB-2 oncoprotein) in very small tumor samples obtained by Tru-Cut before any treatment and in surgical specimens. In the future, these micromethods will be used systematically with the aim of estimating the value of these potential prognostic factors for therapeutic follow-up of the patients.

Adult↗
PubMed1991

Quantification of absorption, intestinal and hepatic first pass effect in a chronic dog model.

A chronic dog model was used to measure the absorption and to elucidate the site and extent of presystemic metabolism of a selective D1-agonist (CY 208-243). The dog was instrumented with portal vein and carotid artery catheters together with an electromagnetic flow measuring device around the portal vein. After administering [14C]CY 208-243 intrajejunally, absorption rate was defined as the product of porto-arterial substrate difference and portal venous blood flow. The extent of absorption amounted to 34% for total radioactivity and 31% for unchanged drug, this indicating a gastrointestinal first-pass of 9%. In an additional study [14C]CY 208-243 was injected intravenously to the dog; the absorption (29%) and the bioavailability (5%) of CY 208-243 were calculated from the ratio of dose normalized, oral versus intravenous AUC values for total radioactivity and unchanged drug, respectively. These data confirm the absorption value found with the chronic dog model and indicate a global presystemic, i.e. intestinal and hepatic, first-pass effect of 83%. In conclusion, this chronic dog model allows an accurate assessment of drug absorption and a quantification of the gastrointestinal and hepatic first-pass effects.

Administration, Oral↗
PubMed1978

Survey for positive Limulus amoebocyte lysate test in plasma from humans and common research animals.

A survey for positive Limulus amoebocyte lysate tests was conducted on apparently healthy humans, mongrel dogs, rats, mice, rabbits, and squirrel monkeys. Only mongrel dog (45.8%) and human (32.8%) plasma samples gave positive tests. In dogs, a significant correlation between positive Limulus amoebocyte lysate tests and the presence of intestinal parasites was found. Positives found in human plasma samples were thought to be due to the presence of background levels of endotoxin or some possible mimicker substance found in the plasma after chloroform extraction. It was concluded that there was a need to distinguish between these positive Limulus tests and those which represent significant endotoxemia.

Animals↗
PubMed1978

[Aseptic inflammatory reaction in surgery of the knee (author's transl)].

The author reports 15 cases which show the clinical and laboratory characteristics and treatment of the aseptic inflammatory reaction observed after operation on the knee. It should be carefully distinguished from pyogenic arthritis; the clinical signs and the appearance of the synovial fluid are identical. Only laboratory examination permits ones to distinguish them, by the presence or absence of bacteria. This is a benign complication which becomes cured within a few days by common medical anti-inflammatory treatment. The danger is confusion with septic arthritis and the choice of inappropriate treatment, which often causes severe sequelae of even secondary infection. The true cause of this complication which in every way resembles acute inflammatory rheumatism, remains unknown.

Adult↗
PubMed1975

[Chronic knee instability. Technics and results of ligament plasty in sports injuries].

Chronic laxity of the knee in sportsmen is limited in practice, owing to the mechanisms of blockage of rotation, to lesions of the medial and anterior cruciate ligaments, associated or not with tears of the meniscus. Full assessment is essential to draw up a full therapeutic plan. It is very difficult, even when clinical examination is completed by excellent XRays. The great technical facility of operations of musculo-aponeurotic transposition, has led surgeons to discard plastic operations on the ligaments. They do, however, give the best chance of return to sporting activity. Two techniques are discussed, one a plastic of the medial ligament, the other designed to palliate rupture of the anterior cruciate ligament. These operations are strong and precise straightaway but the prognosis depends mainly on the number of structures affected.

Athletic Injuries↗