[Appropriate medication prescribing in older people]. / Bon usage des médicaments chez le sujet âgé.

Drug-induced adverse effects are one of the main avoidable causes of hospitalization in older people. Numerous lists of potentially inappropriate medications for older people have been published, as national and international guidelines for appropriate prescribing in numerous diseases and for different age categories. The present review describes the general rules for an appropriate prescribing in older people and summarizes, for the main conditions encountered in older people, medications that are too often under-prescribed, the precautions of use of the main drugs that induce adverse effects, and drugs for which the benefit to risk ratio is unfavourable in older people. All these data are assembled in educational tables designed to be printed in a practical pocket format and used in daily practice by prescribers, whether physicians, surgeons or pharmacists.

[Lyophilization protection of hemoglobin by N-acetyltryptophan]. / Lyoprotection de l'hémoglobine par le N-acétyl tryptophane.

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.

Microencapsulation III: Preparation of invertase microcapsules.

Invertase was incorporated into polyamide microcapsules. The following parameters were studied: pH of the aqueous phase during interfacial polymerization; duration of the polymerization; surfactant concentration; stirring rate; improvements in the isolation procedure; effect of lyophilization. The inactivation of the encapsulated enzyme by pepsin was shown to be related to the acidic incubation medium and prompted incorporation of protective proteins in the microcapsules. This process allowed relative protection of the enzyme. In a second set of experiments, an emulsification-reticulation method was developed, which encapsulated invertase in a cross-linked protein. Various proteins and bifunctional acylating agents were tested. Microcapsules of immobilized invertase were prepared through cross-linking of the enzyme protein itself.

Microencapsulation IV: Cross-linked hemoglobin microcapsules.

Hemoglobin microcapsules were prepared through cross-linking of hemoglobin itself with various acyldichlorides. Variations in the reticulation conditions were preformed in order to ameliorate the oxygen dissociation curve, the mean diameter, and the possibility for the microcapsules to be lyophilized. With terephthaloylchloride, as the cross-linking agent, incorporation of inositol hexaphosphate and glucose, followed by stabilization through glutaraldehyde and using high stirring speed, allowed preparation of stable hemoglobin microcapsules, 5 micrometers in diameter, which suffered rapid lysis by proteases. They were able to ensure oxygen transfer: the dissociation curve was sigmoidal with a p50 = 13 mm Hg. They retained these properties after lyophilization followed by rehydration.