[Electronic cigarettes and fertility: True or false friends?] / Cigarette électronique et fertilité : vrais ou faux amis ?

While electronic cigarettes have been on the rise in France for the past ten years, data on their prevalence, use patterns and safety have remained fragmented and controversial. Electronic cigarettes seem to not be a harmless product to use, because although they contain fewer harmful substances than traditional cigarettes, they still contain toxic products such as endocrine disruptors, which appear to have a negative impact on hormonal homeostasis, morphology and functioning of the animal reproductive system. Mostly presented as a harmless alternative to traditional cigarettes by industry lobbies, electronic cigarettes are often offered as an aid to smoking cessation in the same way as nicotinic substitutes. This strategy is especially proposed without knowledge of its effects on human reproductive health. Indeed, there are currently very few scientific publications, which study the impact of the use of electronic cigarettes, nicotine and the vapours it delivers on fertility and the functioning of the human female and male reproductive systems. Thus, the great majority of the data we have to date come from studies carried out in animal populations and show that electronic cigarettes exposure affect fertility. There is, to our knowledge, no scientific publication on the results in Assisted Reproductive Technology in case of use of electronic cigarettes, motivating the realization of the study IVF-VAP currently underway in the department of Medicine and Biology of Reproduction of the Amiens Picardie University Hospital.

Rotational (de)-excitation of C5 by collision with He at low temperature.

An appropriate estimation of the abundance of the observed C5 radical in the interstellar medium requires accurate radiative and collisional rate coefficients. We present the first two-dimensional potential energy surface (2D-PES) for the ground electronic state of the C5(X1Σ+)-He(X1S) van der Waals system, obtained using an explicitly correlated coupled-cluster method with single, double, and perturbative triple excitations (RCCSD(T)-F12). This PES is subsequently used in quantum close-coupling (CC) scattering calculations. Collisional excitation cross-sections of the rotational levels of C5 by He were calculated for energies up to 1500 cm-1 using the standard (CC) method. The thermal dependence of the corresponding rate coefficients is given for the low and moderate temperature T ≤ 300 K regime of interstellar molecular clouds. This is the first study on the collisional rate coefficients for this system and may have important implications for the astrophysical detection of C5(X1Σ+) and modeling of carbon-rich media.

Rotational quenching of an interstellar gas thermometer: CH3CNHe collisions.

Among all the molecular species found in the interstellar medium, molecules with threefold symmetry axes play a special role, as their rotational spectroscopy allows them to act as practical gas thermometers. Methyl-cyanide (CH3CN) is the second most abundant of those (after ammonia). We compute in this paper the collisional dynamics of methyl-cyanide in collision with helium, for both the A- and the E-symmetries of CH3CN. The potential energy surface is determined using the CCSD(T)-F12b formalism and fit with convenient analytic functions. We compute the rotationally inelastic cross sections for all levels up to 510 cm-1 of collision energy, employing at low energy exact Coupled Channels methods, and at higher energies, approximate Coupled States methods. For temperatures from 7 K up to 300 K, rates of quenching are computed and most are found to differ from those reported earlier (up to a factor of a thousand), calling for a possible reexamination of the temperatures assigned to low density gasses.

Interaction of the simple carbene c-C3H2 with H2: potential energy surface and low-energy scattering.

Cyclopropenylidene, c-C3H2, is a simple hydrocarbon, ubiquitous in astrophysical gases, and possessing a permanent electric dipole moment. Its readily observed rotational transitions make it an excellent probe for the physics and history of interstellar matter. The collisional properties of c-C3H2 with the main background gas, H2, are computed here. We present a full 5-D Potential Energy Surface in the rigid molecule approach, and fit it to relevant functionals for subsequent scattering. We perform low-energy quantum scattering at energies less than 50 cm-1. We use both ortho and para H2 as projectiles. We determine the quality of the various approximations to exact coupled channel scattering and examine paths to go towards higher energy scattering relevant for astrophysics. We compare the results obtained here with earlier ones for scattering with helium.

Rotational (de)-excitation of cyclic and linear C3H2 by collision with He.

Among the closed-shell hydrocarbons, the carbenes c- and l-C3H2 are the lightest ones to display a permanent electric dipole moment and be detectable by rotational spectroscopy. The cyclic form, cyclopropenylidene, is ubiquitous in the InterStellar Matter (ISM) of the Milky Way and external galaxies. As such, it serves as a marker to help in characterizing the physical conditions of the ISM. The linear form, propadienylidene, is less abundant. In order to get access to their absolute and relative abundances, it is essential to understand their collisional excitation/quenching schemes. We compute here a precise ab initio potential energy surface for the interaction of c- and l-C3H2 with helium, by means of a CCSD(T)-F12a formalism and a fit onto relevant spherical harmonics functions. We conduct quantum dynamical scattering in order to get precise cross sections using a coupled-channel approach for solving the nuclear motion. We average sections to have rates for rotational quenching from 5 to 150 K. We show that these new rates are vastly different, up to more than an order of magnitude, from the older rates presented in the literature, computed with angular momentum algebra only. We expect large differences in the astrophysical analyses of C3H2, including the chemical history of those ubiquitous carbenes.

Molecular characterization of Bemisia tabaci populations in Tunisia: genetic structure and evidence for multiple acquisition of secondary symbionts.

A survey was conducted during 2009-2010 seasons to identify the distribution of Bemisia tabaci (Gennadius) biotypes in Tunisia. The genetic affiliation of collected populations was determined by polymerase chain reaction (PCR)-restriction fragment-length polymorphism (TaqI) of the mitochondrial cytochrom oxidase I (mtCOI) gene. Results, validated by sequencing and phylogenetic analysis, allowed the clustering of sampled sweetpotato whiteflies into B and Q biotypes. As B. tabaci harbors the obligatory bacterium Portiera aleyrodidarum, and a diverse array of secondary symbionts including Rickettsia, Hamiltonella, Wolbachia, Cardinium, Arsenophonus, and Fritschea, we report here the infectious status of Tunisian populations by secondary symbionts to find out a correlation between bacterial composition to biotype. The genetic variability and structure of B. tabaci populations in Tunisia was driven by analysis of molecular variance (AMOVA) and the hypothesis of isolation by distance was explored. Selective neutrality and genetic haplotype network tests suggested that Tunisian sweetpotato whiteflies have been undergoing a potential expansion followed by gene flow restriction.

[Embryonnary metabolomics]. / Métabolomique embryonnaire.

Non invasive methods to assess embryo quality become essential in ART. Non invasive proteomic and metabolomic analysis of protein expression (secretome) try to identify novel biomarkers of development and viability of human embryo.

[Ocular findings in megaloblastic anemia associated with diabetes. A case report]. / Complications oculaires de l'association anemie de biermer et diabete. A propos d'un cas.

Ocular involvements of Biermer's anaemia are rarely reported in literature. We present a case of Biermer's anaemia associated with diabetes. Ocular examination showed important conjinctival paleness, diffuse retinal ischemia, Roth's tasks, macular oedema and ischemic optic neuropathy. The patient was treated with vitamin B12 intramusculary. A month later, on examination, we noted a regression of optic neuropathy, the aggravation of ischemic retinopathy and persistence of macular oedema. The patient was treated with laser photocoagulation. The majority of ocular manifestations are reversible if treatment is underlaken early. The combination of diabetes with Biermer's anemia deteriorates the ischemic retinopathy and aggavates its prognosis.

Kinetic analysis of the effect on Fab binding of identical substitutions in a peptide and its parent protein.

Monoclonal antibody 57P, which was raised against tobacco mosaic virus protein, cross-reacts with a peptide corresponding to residues 134-146 of this protein. Previous studies using peptide variants suggested that the peptide in the antibody combining site adopts a helical configuration that mimics the structure in the protein. In this study, we carried out a detailed comparison of Fab-peptide and Fab-protein interactions. The same five amino acid substitutions were introduced in the peptide (residues 134-151) and the parent protein, and the effect of these substitutions on antibody binding parameters have been measured with a Biacore instrument. Fabs that recognize epitopes located away from the site of mutations were used as indirect probes for the conformational integrity of protein antigens. Their interaction kinetics with all proteins were similar, suggesting that the substitutions had no drastic effect on their conformation. The five substitutions introduced in the peptide and the protein had minor effects on association rate constants (ka) and significant effects on dissociation rate constants (kd) of the antigen-Fab 57P interactions. In four out of five cases, the effect on binding affinity of the substitutions was identical when the epitope was presented in the form of a peptide or a protein antigen, indicating that antibody binding specifity was not affected by epitope presentation. However, ka values were about 10 times larger and kd values about 5 times larger for the peptide-Fab compared to the protein-Fab interaction, suggesting a different binding mechanism. Circular dichroism measurements performed for three of the peptides showed that they were mainly lacking structure in solution. Differences in conformational properties of the peptide and protein antigens in solution and/or in the paratope could explain differences in binding kinetics. Our results demonstrate that the peptides were able to mimic correctly some but not all properties of the protein-Fab 57P interaction and highlight the importance of quantitative analysis of both equilibrium and kinetic binding parameters in the design of synthetic vaccines and drugs.

Cytogenetic and cryobiology of human cocultured embryos: a 3-year experience.

PURPOSE: Coculture, which allows good-quality human blastocysts with good yields to be obtained, has been designed mainly to select the best embryos for transfers. METHODS: In a first attempt during coculture, we have studied by fluorescent in situ hybridization the chromosomic content of the in vitro blocked embryos, using centrometric probes for chromosomes 1, 12, and 18. Close to 37% of the arrested embryos show aneuploidymosaicism. RESULTS: Freezing cocultured blastocysts gives good recovery rates after transfer (83%). The ongoing pregnancy rates per transfer (19%) are high, and the implantation rate per embryo is 13%. This compares favorably with freezing at an early stage. CONCLUSIONS: We observed that the quality of the endometrium is always the limiting step, as first of all we observed wide variations according to the hormonal preparation of the patients. Moreover the implantation per embryo in the pregnant patients is very high (57%), indicating that most of the losses are directly related to the receptivity of the endometrium.