[Function of aurora kinase C (AURKC) in human reproduction]. / Rôle d'aurora kinase C (AURKC) dans la reproduction humaine.

Infertility concerns at least 70 million couples worldwide. An important proportion of cases is believed to have a genetic component, yet few causal genes have been identified so far. Hundreds of genes are probably involved in spermatogenesis and oogenesis and this genetic heterogeneity has so far hindered the identification of genes causing infertility in the human. Careful morphological examination of spermatozoa can provide cues to identify homogeneous cohorts of patients likely to have the same genetic defect. We studied a cohort of North-Africans patients with a rare phenotype of large-headed spermatozoa. Using a homozygosity mapping strategy, we could map the morbid gene and we identified the same homozygous mutation (c.144delC) in the aurora kinase C gene (AURKC) of all patients studied initially. We then genotyped a total of 62 patients. All who had a typical phenotype with close to 100% large-headed spermatozoa were homozygously mutated (n=34), whereas no AURKC mutations were detected in the others. A carrier frequency of 1/50 was established from individuals from the Maghrebian population, indicating that 1 in 10,000 men from North-African can be expected to present this form of infertility, a frequency comparable to that of Y-microdeletions, thus far the only known recurrent genetic event altering spermatogenesis. Then we demonstrated by flow cytometry that all spermatozoa have in fact a homogeneous 4C. We recommend the realisation of a molecular diagnosis to all patients with large-headed spermatozoa. ICSI is formally contraindicated for all homozygous patients who can have recourse to donor sperm or adoption. One cannot be as categorical for the patients not harbouring an AURKC mutation.

Scanning electron microscopy study on nanoemulsions and solid lipid nanoparticles containing high amounts of ceramides.

Ceramides are the most important intercellular lipids of the stratum corneum, regulating the barrier function of the skin and participating as second signal messenger in stress-induced apoptosis. The high lipophilicity of ceramides presents a pharmacological problem. In order to overcome this problem two lipophilic delivery systems were used for the incorporation of the ceramides: (1) nanoemulsions (NE) and (2) solid lipid nanoparticles (SLN). The influence of the incorporation of ceramides on the particle shape, size and Polydispersity Index was investigated by photon correlation spectroscopy (PCS) and scanning electron microscopy (SEM). The results showed that NE can incorporate larger amounts of ceramides than SLN (up to 23.2% and 5% of lipid matrix, respectively) without any significant alteration on the morphology of the dispersed particles. The incorporation of higher amounts of ceramides into SLN, leads to anisometric platelet-like formations that are known to be caused by the transition of triglycerides from alpha- to beta-mesomorph. The results of this study can be useful for the design of appropriate delivery systems and for further pharmacological evaluations.

Novel bioseparations using two-phase aqueous micellar systems.

We review our recent experimental and theoretical work aimed at investigating the potential use of two-phase aqueous micellar systems for the separation or concentration of hydrophilic biomaterials using the principle of liquid-liquid extraction. The systems studied include (1) a two-phase aqueous micellar system composed of the nonionic surfactant n-decyl tetra(ethylene oxide) (C(10)E(4)) and (2) a two-phase aqueous micellar system composed of the zwitterionic surfactant dioctanoyl phosphatidyl-choline (C(8)-lecithin). The experimental partitioning behavior of several hydrophilic proteins, including cytochrome (c), soybean trypsin inhibitor, ovalbumin, bovine serum albumin, and catalase, in two-phase aqueous C(10)E(4) and C(8)-lecithin micellar systems is reviewed. A theoretical formulation of the protein partitioning behavior, based on a description of excluded-volume interactions between the hydrophilic proteins and the micelles, is also reviewed. The theoretically predicted protein partitioning behavior is compared with that observed experimentally and is found to be in good agreement. The results of our investigation suggest that two-phase aqueous micellar systems of the type examined in this article are indeed potentially useful as extractant phases for the separation or concentration of proteins and other biomaterials.