[Comparison of birth weights of children born after slow frozen embryo replacement versus fresh embryo transfer]. / Embryons vitrifiés, embryons frais : comparaison des poids de naissance.

OBJECTIVE: It is already known that children born after slow frozen embryo replacement have a significantly higher birth weight compared to children born after fresh embryo transfer. Similar data have been reported related to frozen embryo transfer using an open vitrification system. However, few data relative to birth weight using a complete embryo closed vitrification system has been reported. The purpose of this study was to know if frozen embryo in closed vitrification system is associated with a higher birth weight compared to fresh embryo replacement. DESIGN: This was a monocentric retrospective cohort study, 371 children were issued from fresh embryo replacement and 127 from vitrified embryo transfer. MATERIALS AND METHODS: All singletons born after fresh or vitrified embryo transfer between January 2011 and April 2015 were included. Births from the vitrified or fresh transfers of egg or sperm donation, and preimplantation genetic diagnosis were excluded. In addition, pregnancies with more than one gestational sac at the first ultrasound were excluded. An analysis of covariance (ANCOVA) was used for multivariate analysis. RESULTS: Mean birth weight was 205g higher in the frozen embryo compared with fresh embryos transfer groups (3368g vs. 3163g respectively, P<0.001). This difference remained after multivariate analysis adjusted on confounding factors such as gestational age, maternal age, maternal body mass index (BMI), tobacco exposure, number of embryo transferred and birth order (P<0.001).. CONCLUSIONS: Embryo frozen in closed vitrification system is associated with a higher birth weight compared to fresh embryo replacement. Our findings are consistent with the previous studies related to slow freezing and open vitrification systems data. The effects of controlled ovarian stimulation (COS), ex vivo culture conditions and cryopreservation systems on birth weight of children born should be further explored.

[What do chemotherapy specialists expect of lung cancer?] / Qu'attendent les médecins spécialistes de la chimiothérapie des cancers du poumon ?

OBJECTIVE: In an attempt to understand physicians' expectations of chemotherapy, a group of lung cancer specialists was involved in an online survey investigating their opinions by a self-questionnaire. The questionnaire described five different chemotherapy prescription situations for lung cancer patients (stages IIIB or IV). METHOD: A total of 30 expert specialists were invited; 22 responded (73%). For each of the clinical situations, the expert was asked for his opinion on 3 items: cure, prolongation of survival and alleviation of symptoms. Each item was judged on a Likert scale with categories between -2 "not at all probable" and +2 "quite likely". RESULTS: For "cure", the percentage of -2 responses differed significantly according to the clinical situation (Fisher test: P<0.00001). The trend test showed a relationship between the percentage of -2 responses and the suspected order of the clinical situations (Cochran-Armitage trend test: P<0.0001). For symptom alleviation, the percentage of responses +2 and +1 differed significantly according to the clinical situation (Fisher test: P=0.00013, trend test: P<0.0001). CONCLUSION: What specialist physicians expect of chemotherapy in terms of curability and symptom relief differs according to the actual statistical prognosis of each situation as presented in the literature. The worst prognostic situation leads to the strongest expectation in terms of symptom relief and, conversely, the lowest for curability.

Isolation, structural studies and chemical synthesis of a 'palmitone lipid' from Corynebacterium diphtheriae.

The isolation of a 'palmitone lipid' from Corynebacterium diphtheriae is described. The use of a temporary hydrophobic protecting group allows the obtaining of the lipid in free and pure form. Structural studies by chemical degradation and mass spectrometry allow one to propose structure Ic for this compound, namely 6-(2-tetradecyl 3-keto octadecanoyl)-alpha-D-trehalose. This structure was confirmed by chemical synthesis.

[Separation of structural studies of the molecular species of monomycolates and dimycolates of alpha-D-trehalose present in Mycobacterium phlei (author's transl)]. / Séparation et étude structurale des espèces moléculaires de monomycolates et de dimycolates de alpha-D-tréhalose présents chez Mycobacterium phlei

Mixtures of dimycolates of alpha-D-trehalose (cord factor) and monomycolates have been isolated from Mycobacterium phlei and separated as trimethylsilyl derivatives according to the polarity of the fatty acid residues. The free glycolipids can be recovered by mild hydrolysis. Silylation and disilylation reactions did not induce any isomerisation. The structure of these trehalose esters has been determined by using a series of reactions elaborated on synthetic acyl-sugar models. Free hydroxyl groups are transformed into tetrahydropyran ethers, deacylated by dimsyl sodium, methylated and the sugar derivatives are hydrolyzed. The O-methyl-sugars obtained contain a methyl ether group located at the position where the acyl group was present initially. Identification by gas chromatography of the O-methyl-sugars thus allows the location of the fatty acid residues in the glycolipid. It has been demonstrated that no migration occurs. Two types of 6-monomycoloyl-alpha-D-trehalose have been isolated, differing by the nature of the mycolic acid residues. One of them, called MA, contains "alpha-phlei mycolic acid". The other one, called MB, contains "gamma-phlei mycolic acid" which is the ester of 2-eicosanol with the omega-carboxyl function of a dicarboxylic mycolic acid. Three types of 6,6'-dimycoloyl-alpha-D-trehalose (cord factor) have been obtained. Two of them are symmetrical diesters, containing either two residues of alpha-mycolic acid, or two residues of gamma-mycolic acid. The last one is an unsymmetrical diester, the hydrolysis of which gives one mole of alpha-mycolic acid and one mole of gamma-mycolic acid. The ratio of the different diesters in the cord factor fraction might be explained by some equilibrium between the different 6-ester groups or by a transformation in situ of one species into another one by biochemical modification of the mycolic acid residues.