Comprehensive determination of the cyclic FEE peptide chemical stability in solution.

The FEE cyclic hexapeptide (cFEE) is an investigational new drug added to the insemination medium in order to improve the in vitro fertilization rate. The pharmacological activity of small peptides is highly dependent on the conservation of the amino acid sequence and of the structural conformation of the active site. To enhance the scientific knowledge required for the clinical use of cFEE, a comprehensive determination of its chemical stability in solution was realized in accelerated conditions. Degradation products have been detected and identified by liquid chromatography/Qtrap(®) mass spectrometry. The main degradation products highlighted during the product shelf life were produced by hydrolysis and only certain sites were involved. In most cases, the cyclic conformation was lost and regarding the major degradation pathway, the sequence representing the active site was affected.

Mycobacterial polar glycopeptidolipids enhance resistance to experimental murine candidiasis.

Intraperitoneal administration of polar glycopeptidolipids extracted from Mycobacterium chelonae (pGPL-Mc) greatly increased the resistance of mice against a lethal disseminated Candida albicans infection. This enhanced resistance was demonstrated by an increase in the number of survivors and the prolongation of the mean survival time of animals following a lethal challenge. These effects were dependent upon the infective dose of Candida albicans, the dose of pGPL-Mc and the timing of its administration. This enhanced resistance was correlated with the development and persistence of a hyperleukocytosis, associated with a long lasting increase in the number of polymorphonuclear neutrophils. On the contrary, no candidacidal effect of the serum collected from pretreated mice was observed; suggesting that the ability of pGPL-Mc to increase resistance against Candida albicans infection is likely to be mediated by polymorphonuclear neutrophils. These results confirm previously described immunostimulating properties of pGPL-Mc and open the way for the evaluation of its effect in the prevention of opportunistic infections in neutropenic patients.

Enhanced resistance against lethal disseminated Candida albicans infection in mice treated with polar glycopeptidolipids from Mycobacterium chelonae (pGPL-Mc).

Intraperitoneal administration of polar glycopeptidolipids extracted from Mycobacterium chelonae (pGPL-Mc) greatly increased the resistance of mice against a lethal disseminated Candida albicans infection. This enhanced resistance was demonstrated by an increase in the number of survivors and the prolongation of the mean survival time of animals following a lethal challenge. These effects were dependent upon the infective dose of Candida albicans, the dose of pGPL-Mc and the timing of its administration. This enhanced resistance was correlated with the development and persistence of a hyperleukocytosis, associated with a long lasting increase in the number of polymorphonuclear neutrophils. On the contrary, no candidacidal effect of the serum collected from pretreated mice was observed; suggesting that the ability of pGPL-Mc to increase resistance against Candida albicans infection is likely to be mediated by polymorphonuclear neutrophils. These results confirm previously described immunostimulating properties of pGPL-Mc and open the way for the evaluation of its effect in the prevention of opportunistic infections in neutropenic patients.

Synergic inhibitory activity of amphotericin-B and gamma interferon against intracellular Cryptococcus neoformans in murine macrophages.

Cryptococcus neoformans is responsible for pulmonary and meningal infections in HIV patients. The lack of effective cellular cooperation caused by the low level of CD4+ cells, and the resistance of C. neoformans to phagocytosis allows growth and persistence of the yeast in the host. We describe here an in-vitro model of intracellular replication of C. neoformans inside J774-A.1 macrophages, and the determination of the intracellular antifungal activity of amphotericin B and fluconazole alone or in association with IFN-gamma. The maximum inhibitory effect was observed with one MIC of amphotericin B and 100 or 1000 IU/mL of IFN-gamma. amphotericin B alone (at 1 x MIC), or either 1 x or 50 x MIC of fluconazole in normal or IFN-gamma activated macrophages, did not eradicate the ingested yeast. A potential underlying mechanism of the synergy of amphotericin B in IFN-gamma primed macrophages was investigated by measurement of nitrite level and by use of the NO synthase competitive inhibitor, NG-monomethyl L-arginine (NMMA). One MIC of amphotericin B was able to activate the synthesis of nitrogen reactive intermediates in IFN gamma-primed macrophages. NMMA treated infected macrophages responded less well to IFN-gamma priming, resulting in a moderate inhibition in subsequent amphotericin B exposure.

Comparative in vitro activities of pristinamycin, its components, and other antimicrobial agents against anaerobic bacteria.

Using an agar dilution technique, we compared the activities of pristinamycin and its components PIA and PIIA with those of penicillin G, cefoxitin, chloramphenicol, metronidazole, and clindamycin against 200 strains of anaerobic bacteria isolated from suppurative lesions. The antimicrobial activity of pristinamycin was similar to that of chloramphenicol. On the basis of these results and because of its antistaphylococcal and antistreptococcal activities and its absence of toxicity, pristinamycin might be a valuable therapeutic agent for treating mixed aerobic-anaerobic cutaneous infections.