Spatial Properties of Entangled Two-Photon Absorption

We experimentally study entangled two-photon absorption in rhodamine 6G as a function of the spatial properties of a high flux of broadband entangled photon pairs. We first demonstrate a key signature dependence of the entangled two-photon absorption rate on the type of entangled pair flux attenuation: linear, when the laser pump power is attenuated, and quadratic, when the pair flux itself experiences linear loss. We then perform a fluorescence-based Z-scan measurement to study the influence of beam waist size on the entangled two-photon absorption process and compare this to classical single- and two-photon absorption processes. We demonstrate that the entangled two-photon absorption shares a beam waist dependence similar to that of classical two-photon absorption. This result presents an additional argument for the wide range of contrasting values of quoted entangled two-photon absorption cross sections of dyes in literature.

Dynamics of the femtosecond laser-triggered spark gap

We present space and time resolved measurements of the air hydrodynamics induced by femtosecond laser pulse excitation of the air gap between two electrodes at high potential difference. We explore both plasma-based and plasma-free gap excitation. The former uses the plasma left in the wake of femtosecond filamentation, while the latter exploits air heating by multiple-pulse resonant excitation of quantum molecular wavepackets. We find that the cumulative electrode-driven air density depression channel plays the dominant role in the gap evolution leading to breakdown. Femtosecond laser heating serves mainly to initiate the depression channel; the presence of filament plasma only augments the early heating.

Impact of cancer chemotherapy before ovarian cortex cryopreservation on ovarian tissue transplantation

STUDY QUESTION

How efficacious is transplantation of ovarian cortex previously exposed to chemotherapy?

SUMMARY ANSWER

Prior exposure to chemotherapy did not disrupt the function of cryopreserved ovarian tissue after transplantation.

WHAT IS KNOWN ALREADY

Ovarian tissue cryopreservation (OTC) followed by ovarian tissue transplantation (OTT) is an efficacious technique for restoration of female fertility. At least 130 children have been born following this procedure. To date, little is known about the efficacy of OTT in patients exposed to cancer chemotherapy prior to OTC.

STUDY DESIGN, SIZE, DURATION

This study evaluates the recovery of ovarian function and fertility in 31 consecutive patients who had received OTT, between 2005 and 2015.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Thirty one patients, wanting children, were transplanted with autologous ovarian cortex, among which 22 patients (71%) had been exposed to chemotherapy before OTC. Recovery of ovarian function was considered total once menstruation occurred. Ovarian function recovery (OFR), ovarian graft survival, and incidence of pregnancy were related to previous chemotherapy exposure, type of chemotherapy and graft characteristics (number of grafted fragments and follicular density).

MAIN RESULTS AND ROLE OF CHANCE

The amount of ovarian tissue collected was the only parameter to show any significant change between patients with versus without previous chemotherapy. At 1 year after OTT, the cumulative incidence of OFR was 83% (93% in patients exposed to chemotherapy and 67% in others (P = 0.14)). A low follicular density (<0.3 foll/mm2) in the transplant and a low number of grafted fragments (<16) were significantly associated with a delayed OFR. Graft survival at 2 years after OTT was 77%. It was significantly lower in patients exposed to bifunctional alkylating agents before ovarian cryopreservation and in patients with a low follicular density. The proportion of women who succeeded in having at least one live birth was 23% in the total population, 0% (0/9) in the group 'no previous chemotherapy', and 32% (7/22) in the group 'previous chemotherapy'. The cumulative incidence of pregnancy (Kaplan-Meier) at 3 years after OTT was 36% overall and 49% in case of previous chemotherapy, with no difference related to previous chemotherapy exposure. In total there were 13 pregnancies and 8 births in 7 patients.

LIMITATIONS, REASONS FOR CAUTION

The pathology in the two groups of patients was not comparable. In the group of patients who had chemotherapy before OTC, there were 95% of hematological malignancies. In the group of patients who did not have chemotherapy before OTC only 1 out of 9 patients had a malignant hematological disease while 44% had some pathology affecting the ovaries. Few women are available for study and only large changes are likely to have statistical significance.

WIDER IMPLICATIONS OF THE FINDINGS

These results suggest that prior cancer chemotherapy should no longer be considered a limitation to cryopreservation of ovarian tissue and current recommendations in this regard should be revised.

STUDY FUNDING/COMPETING INTEREST(S)

This study was supported by the Agence de la Biomédecine (France's biomedical office). There are no competing interests to report.

TRIAL REGISTRATION NUMBER

NCT02184806.

JUNO, the receptor of sperm IZUMO1, is expressed by the human oocyte and is essential for human fertilisation

STUDY QUESTION

Is JUNO protein present at the surface membrane of human oocytes and involved in the fertilisation process?

SUMMARY ANSWER

JUNO protein is expressed on the plasma membrane of human oocytes and its inhibition by a monoclonal antibody completely blocks gamete fusion.

WHAT IS KNOWN ALREADY

Fusion of gamete membranes is the culminating event of the fertilisation process, but its molecular mechanisms are poorly understood. Until now, three molecules have been shown to be essential: CD9 tetraspanin in the oocyte, Izumo1 protein on the sperm and Juno, its corresponding receptor on the oocyte. Oocyte CD9 and sperm IZUMO1 have been identified in human gametes and their interaction is also well-conserved among several mammalian species. The presence of JUNO on human oocytes, however, has not yet been reported, nor has its role in fertilisation been investigated.

STUDY DESIGN, SIZE, DURATION

We selected an anti-human JUNO antibody in order to investigate the presence of JUNO on the oocyte membrane surface and studied its potential involvement in gamete membrane interaction during fertilisation.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Monoclonal antibodies against human JUNO (anti-hJUNO mAb) were produced by immunisation of mice with HEK cells transfected with the putative human JUNO sequence (HEK-hJUNO). These antibodies were used for immunostaining experiments and in vitro fertilisation assays with human gametes (GERMETHEQUE Biobank).

MAIN RESULTS AND THE ROLE OF CHANCE

Three hybridoma supernatants, verified by immunostaining, revealed specifically HEK-hJUNO cells. The three purified monoclonal antibodies, FJ2E4 (IgG1), FJ8E8 (IgG1) and FJ4F5 (IgG2a), recognised the soluble recombinant human JUNO protein and, in a western blot of HEK-hJUNO extracts, a protein with an expected MW of 25 kDa. In addition, soluble recombinant human IZUMO protein inhibited the binding of anti-hJUNO mAbs to cells expressing hJUNO. Using these anti-hJUNO mAbs in immunostaining, we identified the presence of JUNO protein at the plasma membrane of human oocytes. Furthermore, we revealed a progressive expression of JUNO according to oocyte maturity. Finally, we showed that human zona-free oocytes, inseminated in the presence of anti-hJUNO mAb, were not fertilised by human sperm. These results suggest that, as seen in the mouse, JUNO is indeed involved in human gamete membrane fusion during fertilisation.

LARGE-SCALE DATA

N/A.

LIMITATIONS, REASONS FOR CAUTION

In accordance with French bioethics laws, functional tests were performed using zona-free oocytes, which of course does not fully encompass all normal in vivo physiological conditions. However, these in vitro tests do provide direct information regarding sperm-oocyte membrane interactions.

WIDER IMPLICATIONS OF THE FINDINGS

Mechanisms of gamete fusion appear to be homologous between mice and humans. However, some differences do exist and analysing the human mechanisms is essential. In fact, this is the first report describing the presence of JUNO on human oocytes and its involvement in human fertilisation. This discovery allows further examination of the understanding of molecular mechanisms that drive gamete fusion: a crucial challenge at a time when infertility affects 16% of reproductively active couples.

STUDY FUNDING/COMPETING INTERESTS

This work was supported by the Agence Nationale pour la Recherche, Grant no. ANR-13-BVS5-0004, and by Association Institut du Cancer et d'Immunogénétique (ICIG). There are no competing interests.

Growth arrest specific 1 (Gas1) and glial cell line-derived neurotrophic factor receptor α1 (Gfrα1), two mouse oocyte glycosylphosphatidylinositol-anchored proteins, are involved in fertilisation

Recently, Juno, the oocyte receptor for Izumo1, a male immunoglobulin, was discovered. Juno is an essential glycosylphosphatidylinositol (GIP)-anchored protein. This result did not exclude the participation of other GIP-anchored proteins in this process. After bibliographic and database searches we selected five GIP-anchored proteins (Cpm, Ephrin-A4, Gas1, Gfra1 and Rgmb) as potential oocyte candidates participating in fertilisation. Western blot and immunofluorescence analyses showed that only three were present on the mouse ovulated oocyte membrane and, of these, only two were clearly involved in the fertilisation process, namely growth arrest specific 1 (Gas1) and glial cell line-derived neurotrophic factor receptor α1 (Gfrα1). This was demonstrated by evaluating oocyte fertilisability after treatment of oocytes with antibodies against the selected proteins, with their respective short interference RNA or both. Gfrα1 and Gas1 seem to be neither redundant nor synergistic. In conclusion, oocyte Gas1 and Gfrα1 are both clearly involved in fertilisation.

Short-pulse lasers for weather control

Filamentation of ultra-short TW-class lasers recently opened new perspectives in atmospheric research. Laser filaments are self-sustained light structures of 0.1-1 mm in diameter, spanning over hundreds of meters in length, and producing a low density plasma (10¹⁵-10¹⁷ cm^-3) along their path. They stem from the dynamic balance between Kerr self-focusing and defocusing by the self-generated plasma and/or non-linear polarization saturation. While non-linearly propagating in air, these filamentary structures produce a coherent supercontinuum (from 230 nm to 4 µm, for a 800 nm laser wavelength) by self-phase modulation (SPM), which can be used for remote 3D-monitoring of atmospheric components by Lidar (Light Detection and Ranging). However, due to their high intensity (10¹³-10¹⁴ W cm^-2), they also modify the chemical composition of the air via photo-ionization and photo-dissociation of the molecules and aerosols present in the laser path. These unique properties were recently exploited for investigating the capability of modulating some key atmospheric processes, like lightning from thunderclouds, water vapor condensation, fog formation and dissipation, and light scattering (albedo) from high altitude clouds for radiative forcing management. Here we review recent spectacular advances in this context, achieved both in the laboratory and in the field, reveal their underlying mechanisms, and discuss the applicability of using these new non-linear photonic catalysts for real scale weather control.

Strong field transient manipulation of electronic states and bands

In the present review, laser fields are so strong that they become part of the electronic potential, and sometimes even dominate the Coulomb contribution. This manipulation of atomic potentials and of the associated states and bands finds fascinating applications in gases and solids, both in the bulk and at the surface. We present some recent spectacular examples obtained within the NCCR MUST in Switzerland.

Gas-Solid Phase Transition in Laser Multiple Filamentation

While propagating in transparent media, near-infrared multiterawatt (TW) laser beams break up in a multitude of filaments of typically 100-200 um diameter with peak intensities as high as 10 to 100  TW/cm^{2}. We observe a phase transition at incident beam intensities of 0.4  TW/cm^{2}, where the interaction between filaments induce solidlike two-dimensional crystals with a 2.7 mm lattice constant, independent of the initial beam diameter. Below 0.4  TW/cm^{2}, we evidence a mixed phase state in which some filaments are closely packed in localized clusters, nucleated on inhomogeneities (seeds) in the transverse intensity profile of the beam, and other are sparse with almost no interaction with their neighbors, similar to a gas. This analogy with a thermodynamic gas-solid phase transition is confirmed by calculating the interaction Hamiltonian between neighboring filaments, which takes into account the effect of diffraction, Kerr self-focusing, and plasma generation. The shape of the effective potential is close to a Morse potential with an equilibrium bond length close to the observed value.

[Information, transmission, secrecy: What kind of discourse for children born by gamete donation?]

The number of children born through gamete donation grows by the conceptions made abroad. All the couples engaging in this process do not benefit from of the same support around the issues raised by the information to the child and its terms. Through a literature review, the authors explore the data on information intentions from parents to child and to entourage, the influence of the issue of anonymity, the effective rate information, the influences of the age of the child, the terms information and links with family dynamics. The quantitative findings underscore the complexity of this task, since 10-90 % of couples report an intention to inform their child from conception through donation, while 5-30 % actually inform them after birth. Fifty-nine to 93 % of the relatives are nevertheless informed. The authors will highlight the psychopathological tracks that support the possibility of narration for parents: the internalization of their infertility, the representation of the gift, the development of rivalry towards donors, the secrecy and privacy. The objective of this article is to enable carers to accompany this reflection among future parents, a better listening of the issues raise by the couples allowing shoring their process.

Spin-Glass Model Governs Laser Multiple Filamentation

We show that multiple filamentation patterns in high-power laser beams can be described by means of two statistical physics concepts, namely, self-similarity of the patterns over two nested scales and nearest-neighbor interactions of classical rotators. The resulting lattice spin model perfectly reproduces the evolution of intense laser pulses as simulated by the nonlinear Schrödinger equation, shedding new light on multiple filamentation. As a side benefit, this approach drastically reduces the computing time by 2 orders of magnitude as compared to the standard simulation methods of laser filamentation.

Laser filamentation as a new phase transition universality class

We show that the onset of laser multiple filamentation can be described as a critical phenomenon that we characterize both experimentally and numerically by measuring a set of seven critical exponents. This phase transition deviates from any existing universality class and offers a unique perspective of conducting two-dimensional experiments of statistical physics at a human scale.

Reversibility of laser filamentation

We investigate the reversibility of laser filamentation, a self-sustained, non-linear propagation regime including dissipation and time-retarded effects. We show that even losses related to ionization marginally affect the possibility of reverse propagating ultrashort pulses back to the initial conditions, although they make it prone to finite-distance blow-up susceptible to prevent backward propagation.

Mid-infrared laser filamentation in molecular gases

We observed the filamentation of mid-infrared ultrashort laser pulses (3.9 μm, 80 fs) in molecular gases. It efficiently generates a broadband supercontinuum over two octaves in the 2.5-6 μm spectral range, with a red-shift up to 500 nm due to the Raman effect, which dominates over the blue shift induced by self-steepening and the gas ionization. As a result, the conversion efficiency into the Stokes region (4.3-6 μm) 65% is demonstrated.

High-field quantum calculation reveals time-dependent negative Kerr contribution

The exact quantum time-dependent optical response of hydrogen under strong-field near-infrared excitation is investigated and compared to the perturbative model widely used for describing the effective atomic polarization induced by intense laser fields. By solving the full 3D time-dependent Schrödinger equation, we exhibit a supplementary, quasi-instantaneous defocusing contribution missing in the weak-field model of polarization. We show that this effect is far from being negligible, in particular when closures of ionization channels occur and stems from the interaction of electrons with their parent ions. It provides an interpretation of the higher-order Kerr effect recently observed in various gases.

[COPD in dairy farmers: screening, characterization and constitution of a cohort. The BALISTIC study]

BACKGROUND

A pilot study from our group suggests that the prevalence of chronic obstructive pulmonary disease (COPD) among dairy farmers is higher than in the general population although dairy workers are less frequently smokers.

OBJECTIVES AND METHODS

The study presented here aims at (i) determining the prevalence of COPD in a large and representative population of dairy farmers; (ii) characterizing these patients in terms of smoking habits, dyspnoea, quality of life, lung function, bronchial exhaled nitric oxide, systemic inflammation, arterial stiffness and exercise capacity; (iii) comparing characteristics of dairy farmers' COPD with the characteristics of COPD in patients without any occupational exposure; (iv) identifying the etiological factors of COPD in dairy farmers; and (v) constituting a cohort of COPD patients and control subjects for further longitudinal studies. Two groups of COPD patients (dairy farmers or not) and two groups of controls subjects will be selected among a representative panel of 2000 dairy workers and 2000 subjects without any occupational exposure, all aged 40 to 75 years.

EXPECTED RESULTS

A better knowledge of the epidemiology and pathophysiology of COPD in dairy farmers should guide a specific strategy of prevention. The knowledge of the characteristics of COPD occurring in dairy farmers will help to define the therapeutic modalities that might be different compared with the therapeutic recommendations for COPD secondary to tobacco smoking.

Ultrafast laser spectroscopy and control of atmospheric aerosols

We review applications of ultrafast laser pulses for aerosol analysis via linear and non-linear spectroscopy, including the most advanced techniques like coherent control of molecular excited states. We also discuss the capability of such pulses to influence the nucleation of atmospheric aerosols by assisting condensation of water in air.

[Pre-washing catheter dramatically improves the post intrauterine insemination pregnancy rate]

OBJECTIVE

To analyze the effectiveness of pre-washing the intrauterine insemination catheters on IUI outcome.

PATIENTS AND METHODS

Infertile couples (n=322) involved in a IUI program were included in the study. IUI indications were cervical factors, ovulation dysfunction, cryopreserved semen and unexplained infertility. Every other week for two years, IUI catheters were washed with culture medium prior to intrauterine sperm insemination.

RESULT(S)

Only the first IUI for each couple were analyzed. Washing the catheter, prior to use, resulted in a 49.7% increase in clinical pregnancy rate (22.0% vs 14.7% P<0.05). This result is observed with fresh sperm (15.7% vs 11.1%) and frozen-thawed sperm as well (31.1% vs 19.8%). The early pregnancy termination rate was similar in all groups.

DISCUSSION AND CONCLUSION

Pre-washing the catheter before IUI should be recommended in Good Laboratory Practice Guidelines as it is already the case for embryo transfer catheters. This raises the problem of washing all single-use devices, in contact with gametes or embryos during IVF.

Coherent manipulation of free amino acids fluorescence

Coherent manipulation of molecular wavepackets in biomolecules might contribute to the quest towards label-free cellular imaging and protein identification. We report the use of optimally tailored UV laser pulses in pump-probe depletion experiments that selectively enhance or decrease fluorescence between two aromatic amino acids: tryptophan (Trp) and tyrosine (Tyr). Selective fluorescence modulation is achieved with a contrast of ~35%. A neat modification of the time-dependent fluorescence depletion signal of Trp is observed, while the Tyr transient trace remains unchanged. The mechanism invoked for explaining the change of the depletion of Trp is a less efficient coupling between the fluorescing state and the higher non-radiative excited states by the optimally shaped pulse, than by the reference pulse.

[Sperm reservoir in mice: involvement of ADAMs]

Mammalian sperm migrate over long distances through the female genital tract before reaching the oviduct where fertilization occurs. This process is more complex than predicted by the movement of sperm. The oviduct is composed of three major segments: the uterotubal junction, the isthmus and the ampulla. These structures appear to play roles for the success of fertilization. Gene knockout approaches of several genes in mice suggest that the migration of spermatozoa in the oviduct is regulated to allow competent gametes encounter ensuring the success of fertilization with minimum risk of polyspermy. The sperm of male mice deleted for following genes: Calmegin, Calsperin, Angiotensin-Converting-Enzyme, Adam1a, Adam2 or Adam3 are morphologically normal and motile, but not able to pass through the uterotubal junction. The precise mechanism of how these molecules facilitate the passage of spermatozoa through the uterotubal junction is still unknown, but Adam3 seems to be the major factor in this process since it is implicated in these six lines of mutant mice.

Transition from plasma-driven to Kerr-driven laser filamentation

While filaments are generally interpreted as a dynamic balance between Kerr focusing and plasma defocusing, the role of the higher-order Kerr effect (HOKE) is actively debated as a potentially dominant defocusing contribution to filament stabilization. In a pump-probe experiment supported by numerical simulations, we demonstrate the transition between two distinct filamentation regimes at 800 nm. For long pulses (1.2 ps), the plasma substantially contributes to filamentation, while this contribution vanishes for short pulses (70 fs). These results confirm the occurrence, in adequate conditions, of filamentation driven by the HOKE rather than by plasma.

From higher-order Kerr nonlinearities to quantitative modeling of third and fifth harmonic generation in argon

The recent measurement of negative higher-order Kerr effect (HOKE) terms in gases has given rise to a controversial debate, fed by its impact on short laser pulse propagation. By comparing the experimentally measured yield of the third and fifth harmonics, with both an analytical and a full comprehensive numerical propagation model, we confirm the absolute and relative values of the reported HOKE indices.

Within 1 h, HIV-1 uses viral synapses to enter efficiently the inner, but not outer, foreskin mucosa and engages Langerhans-T cell conjugates

Although circumcision reduces male acquisition of human immunodeficiency virus type-1 (HIV-1) by 60%, the initial mechanisms of HIV-1 transmission at the foreskin remain elusive. We have established two novel and complementary models of the human adult foreskin epithelium, namely, ex vivo foreskin explants and in vitro reconstructed immunocompetent foreskins. In these models, efficient HIV-1 transmission occurs after 1 h of polarized exposure of the inner, but not outer, foreskin to mononuclear cells highly infected with HIV-1, but not to cell-free virus. HIV-1-infected cells form viral synapses with apical foreskin keratinocytes, leading to polarized budding of HIV-1, which is rapidly internalized by Langerhans cells (LCs) in the inner foreskin. In turn, LCs migrate toward the epidermis-dermis interface to form conjugates with T cells, thereby transferring HIV-1. Seminal plasma mixed with cervicovaginal secretions inhibits HIV-1 translocation. This set of results rationalizes at the cellular level the apparent protective outcome of circumcision against HIV-1 acquisition by men.

Generalized Miller formulae

We derive the spectral dependence of the non-linear susceptibility of any order, generalizing the common form of Sellmeier equations. This dependence is fully defined by the knowledge of the linear dispersion of the medium. This finding generalizes the Miller formula to any order of non-linearity. In the frequency-degenerate case, it yields the spectral dependence of non-linear refractive indices of arbitrary order.

Higher-order Kerr terms allow ionization-free filamentation in gases

We show that higher-order nonlinear indices (n(4), n(6), n(8), n(10)) provide the main defocusing contribution to self-channeling of ultrashort laser pulses in air and argon at 800 nm, in contrast with the previously accepted mechanism of filamentation where plasma was considered as the dominant defocusing process. Their consideration allows us to reproduce experimentally observed intensities and plasma densities in self-guided filaments.

Ultraviolet-visible conical emission by multiple laser filaments

We characterized the angular distribution of the supercontinuum emission from multiple infrared laser filaments propagating in air over long distances, from the infrared (1080 nm) to ultraviolet (225 nm). These experimental data suggest that the X-Waves modeling or Cerenkov emission, rather than phase matching of four-wave mixing, could explain the conical emission. We also estimate the total light conversion efficiency from the original laser wavelength into the white-light continuum.

[A prospective auto-controlled study to evaluate the interest of selected sperm morphology to inseminate oocytes during IVF]

OBJECTIVES

Since we observed in our laboratory a significant decrease of the fertilization rate in the classical IVF procedure compared to ICSI, we wanted to evaluate a new insemination procedure, using sperm morphology of selected semen as a criterion taken into account to calculate the number of mobile sperm to inseminate.

PATIENTS AND METHODS

Therefore, we designed a prospective autocontrolled study which took place from September 2006 to May 2007. All IVF attempts resulting from infertile couples were included in the study if a previous analysis (lesser than one year) of sperm parameters performed in our laboratory was assessed as normal. The retrieved oocytes were separated into two groups (sibling ovocytes), inseminated randomly either with the usual procedure (control group) or with the tested protocol (tested group). Fertilization rate was the primary end point to evaluate this assay. Polyspermy rates were also compared. Subsequently, embryonic quality and development were assessed to eliminate an oxidative stress impact. Paired Student t-test was applied for statistical analysis.

RESULTS

In all, 130 couples were included. The diploid fertilization rate was significantly increased in the tested group compared to the control group (66.9% vs 61.3%; p=0.017). No statistically significant difference was showed between the polyspermy rate and numbers of (i) good quality embryos and (ii) blastomeres per embryo into the two groups.

DISCUSSION AND CONCLUSION

Compared with the conventional insemination procedure, the fertilization rate benefited from the tested insemination method in our laboratory without damaging embryonic growth. In the limit of our procedure, selected sperm morphology should be used to inseminate an appropriate number of spermatozoa within oocytes, even in case of normal semen values.

Ultrafast gaseous "half-wave plate"

We demonstrate that filaments generated by ultrashort laser pulses can induce a remarkably large birefringence in Argon over its whole length, resulting in an ultrafast "half-wave plate" for a copropagating probe beam. This birefringence originates from the difference between the nonlinear refractive indices induced by the filament on the axes parallel and orthogonal to its polarization. An angle of 45 degrees between the filament and the probe polarizations allows the realization of ultrafast Kerr-gates, with a switching time ultimately limited by the duration of the filamenting pulse.

[Prospective evaluation of elective single-embryo transfer versus double-embryo transfer following in vitro fertilization: a two-year French hospital experience]

OBJECTIVE

Multiple embryo transfer is responsible for a high rate of multiple pregnancies (ICSI), with subsequent risks of premature birth and perinatal death. This prospective non randomized study aimed to assess the ability of an elective single-embryo transfer (eSET) policy to reduce the twin pregnancy rate, compared to a double embryo transfer (DET) approach.

PATIENTS AND METHODS

Between March 2005 and May 2006, 180 eligible women were proposed to benefit from an eSET transfer rather than a DET. Inclusion criteria were (i) age less than 37 years old; (ii) at least two good quality embryos available (three to five cells at day 2 or six to nine cells at day 3; less than 20% fragmentation and the absence of multinucleates blastomeres), after IVF or ICSI and (iii) no more than one previous failed treatment cycle. Outcome analysis included cycles with frozen-thawed embryo transfer (FET).

RESULTS

According to patients' decision, 107 and 73 women had an eSET (59.4%) and a DET (40.6%) respectively. No differences were found between eSET and DET groups regarding demographics and biologicals parameters. The clinical pregnancy rate (PR) per transfer was 43.9% in eSET group and 57.5% in DET group (p=0.07). The twin pregnancy rates were 0 and 14.3%, in eSET and DET groups, respectively (p=0.007). The cumulative PR per patient, including the outcome of performed FET cycles, was 63.6% in eSET group and 61.6% in DET group. In this case, the cumulative twin pregnancy rates were 2.9 and 15.6% in eSET and DET groups, respectively (p=0.02).

DISCUSSION AND CONCLUSION

Our data show that in a selected population of women, transferring one fresh embryo and then, if required, one or two frozen-thawed embryos significantly reduces the twin pregnancy rate without decreasing the overall pregnancy rate. This study supports the policy of eSET in this subgroup of patients.

De novo Subtelomeric Deletion Additional to an Inherited Apparently Balanced Reciprocal Translocation

OBJECTIVE

We describe the analysis of an apparently balanced inherited reciprocal translocation in a fetus presenting with multiple congenital abnormalities, characterize the structural chromosome rearrangement, and report an unexpected additional imbalance to the inherited rearrangement.

METHODS

DNA microarray was used to screen for genomic imbalance in subtelomeric and interstitial critical regions. High-resolution comparative genomic hybridization was used to screen for genomic imbalance at a genome-wide level. Fluorescence in situ hybridization using whole-chromosome painting and specific probes was used to characterize the inherited translocation, and the size of the de novoadditional deletion.

RESULTS

An unexpected additional deletion was found in 7qter on derivative 10 of the inherited maternal reciprocal translocation t(7;10)(q11.23; p14).

CONCLUSIONS

We show the usefulness of genome-wide and specific molecular cytogenetic techniques to explore apparently balanced rearrangements.

Semilobar holoprosencephaly prenatal diagnosis: an unexpected complex rearrangement in ade novo apparently balanced reciprocal translocation on karyotype

We report a semilobar holoprosencephaly (HPE) in a post-intracytoplasmic-sperm-injection pregnancy. It was suggested by ultrasonography (US), documented on karyotype, identified with magnetic resonance imaging (MRI), established after birth and confirmed on post-mortem autopsy. An amniocentesis revealed a de novo apparently balanced reciprocal translocation 46,XY, t(7;8) (q31.3;q12). Fluorescence in situ hybridization (FISH) identified a deletion in the region of the Sonic Hedgehog gene (SHH) on der(8); nevertheless, the subtelomeric regions for chromosomes 7 and 8 were present. The parents decided to continue the pregnancy; a boy was born and survived for 3 days. The brain autopsy confirmed the semilobar HPE previously noted on US and MRI. Further, band-specific FISH revealed, in addition to SHH deletion, the presence of an inversion in the 7q translocated material on der(8). The parents' karyotypes were normal. An unexpected complex rearrangement was present in a de novo apparently balanced reciprocal translocation in a semilobar HPE.

A prospective randomized study to assess the benefit of partial zona pellucida digestion before frozen-thawed embryo transfers

BACKGROUND

Assisted hatching (AH) in fresh embryo transfer (ET) could be associated with increased implantation rates. However, very few prospective randomized studies have specifically addressed the issue of AH during frozen-thawed embryo transfers (FET) cycles, those that have reported controversial results. The aim of this study was to evaluate the benefit of an enzymatic zona pellucida treatment of frozen-thawed embryos before transfer.

METHODS

This was a prospective study including 125 non-donor FET cycles from 125 infertile couples. FETs were randomly allocated into AH group (n = 61, embryos pretreated with pronase 5 IU/ml for 1 min at 37 degrees C) or control group (n = 64, untreated embryos). Zona pellucida thickness was measured for each transferred embryo. The main outcome parameters were clinical pregnancy and implantation rates.

RESULTS

The two groups were comparable regarding mean women's age, duration and indications of infertility, IVF outcome after fresh ETs, numbers and quality of fresh and frozen embryos, frozen-thawed embryo survival rates and blastomeres survival indexes. Despite a statistically significant decrease of zona pellucida thickness after pronase treatment [(mean +/- SD) 18.5 +/- 2.25 versus 14.5 +/- 2.75 microm; P < 0.0001], implantation (9.6 versus 9.2%) and clinical pregnancy rates (18.0 versus 17.2%) were not statistically different after FETs, with a similar mean number of embryos transferred between AH and control groups, respectively.

CONCLUSION

Within the constraints of our protocol, partial enzymatic digestion of zona pellucida by pronase was not related with any benefit of the FET outcome especially concerning the implantation ability of frozen-thawed embryos.

Chromosome segregation in an infertile man carrying a unique pericentric inversion, inv(21)(p12q22.3), analysed using fluorescence in situ hybridization on sperm nuclei: significance for clinical genetics. A case report

We report the case of a 40-year-old patient referred to our centre after 3 years of infertility. Karyotyping with the aid of fluorescence in situ hybridization (FISH) analysis showed a unique pericentric inversion of chromosome 21:46,XY,inv(21)(p12q22.3). This type of intrachromosomal structural rearrangement can lead to chromosome imbalance in offspring by producing unbalanced gametes if an odd number of crossover events occur within the inverted segment. Therefore, partial trisomy/monosomy with clinical consequences can be observed in the progeny of carriers. Semen samples from the inversion carrier were analysed by FISH using a combination of probes [a subtelomeric 21q probe and a locus-specific Down's syndrome critical region (DSCR) probe] to evaluate the proportion of recombinant chromosomes. Sperm-FISH analysis of 3400 spermatozoa revealed a 67.4% rate of balanced chromosomes (normal or inverted). The frequencies of recombinant chromosomes with duplication of the long arm and deletion of the short arm, and vice versa, were 11.2 and 21.4%, respectively. The risk for the couple of conceiving a child with an unbalanced chromosome 21 is estimated to be around 32%. This case study shows the utility of sperm-FISH analysis in the genetic counselling of a pericentric inversion in a male carrier to assess the frequency of recombinant chromosomes and therefore evaluate the probability of having a normal conception.

Effects of transdermal testosterone application on the ovarian response to FSH in poor responders undergoing assisted reproduction technique—a prospective, randomized, double-blind study

BACKGROUND

In primates, androgens can play a synergistic role with FSH in promoting the early follicular recruitment, which is critical in assisted reproduction technique programmes.

OBJECTIVE

To assess whether poor responders can benefit from androgen application.

METHODS

Inclusion criteria were a previous poor ovarian response to controlled ovarian stimulation and a decreased hormonal ovarian reserve. Selected women were randomized to receive either transdermal application of testosterone (n = 24) or placebo (n = 25) gel for 15 days before FSH treatment for a second IVF cycle. Similar GnRH analogue and equivalent FSH daily doses were used in both cycles. The primary outcome was the total number of oocytes retrieved.

RESULTS

Testosterone gel application resulted in a significant increase in plasma testosterone levels but did not significantly improve the antral follicle count. Furthermore, after gel application, the main parameters of the ovarian response (numbers of pre-ovulatory follicles, total and mature oocytes and embryos) did not significantly differ between testosterone and placebo-treated patients.

CONCLUSION

No significant beneficial effects of androgen administration on the ovarian response to FSH could be demonstrated. However, subsequent clinical trials are needed to determine whether an optimal dose and/or a longer duration of testosterone administration may be helpful.

Laser filaments generated and transmitted in highly turbulent air

The initiation and propagation of a filament generated by ultrashort laser pulses in turbulent air is investigated experimentally. A filament can be generated and propagated even after the beam has propagated through strongly turbulent regions, with structure parameters C(n)2 as many as 5 orders of magnitude larger than those encountered in the usual atmospheric conditions. Moreover, the filament's position within the beam is not affected by the interaction with a turbulent region. This remarkable stability is allowed by the strong Kerr refractive-index gradients generated within the filament, which exceed the turbulence-induced refractive-index gradients by 2 orders of magnitude.

Hyperstimulation ovarienne : place de la chirurgie

Ovarian hyperstimulation syndrome is a iatrogenic complication that could happen during ovulation induction. Metabolic modifications can lead to a third sector and organic failure. Medical treatment, undertaken in first line, may be insufficient. In these cases, invasive treatment, using surgical techniques, in association with reanimation principles becomes necessary. From the simple drainage to final measures for the patient's rescue, this review describes the different solutions and their respective place. Several means exist, but serious evaluation is lacking. Their use should be indicated specifically. Medico-surgical associations seemed to offer interesting results.

Cyclic FEE peptide increases human gamete fusion and potentiates its RGD-induced inhibition

BACKGROUND

Alpha6beta1 integrin has been proposed to act as a sperm receptor on the mouse oocyte by interacting with spermatozoon fertilin beta. We investigated, in humans, whether oocyte integrins could act similarly in gamete fusion, using a cyclic peptide containing the putative disintegrin-binding domain of human fertilin beta [cyclic FEE (cFEE)] and RGD peptide.

METHODS

Zona-free eggs were inseminated in the absence or presence of peptides. To maintain the membrane protein pattern, the zona pellucida was removed by microdissection. Immunofluorescence and confocal microscopy were used to detect integrin subunits on the oocyte.

RESULTS

Unexpectedly, cFEE alone increased human gamete fusion by 94% instead of inhibiting fertilization. Furthermore, cFEE together with RGD potentiated the RGD-induced inhibition of fertilization in a dose-dependent manner. The data suggested the hypothesis of integrin cross-talk, further supported by the co-localization of alpha6beta1 and alphavbeta3 integrins, the putative receptors of cFEE and RGD peptides, respectively.

CONCLUSIONS

RGD-sensitive and -insensitive integrins may be associated in a multimolecular complex working as a sperm receptor on the human oocyte membrane. Supplementation of human IVF culture medium with cFEE peptide might improve fertilization rates in ART.

Multifilamentation transmission through fog

The influence of atmospheric aerosols on the filamentation patterns created by TW laser beams over 10 m propagation scales is investigated, both experimentally and numerically. From the experimental point of view, it is shown that dense fogs dissipate quasi-linearly the energy in the beam envelope and diminish the number of filaments in proportion. This number is strongly dependent on the power content of the beam. The power per filament is evaluated to about 5 critical powers for self-focusing in air. From the theoretical point of view, numerical computations confirm that a dense fog composed of micrometric droplets acts like a linear dissipator of the wave envelope. Beams subject to linear damping or to collisions with randomly-distributed opaque droplets are compared.

World Health Organization grade 'a' motility and zona-binding test accurately predict IVF outcome for mild male factor and unexplained infertilities

BACKGROUND

The aim of this study was to determine the pronostic value of a sperm-zona pellucida (ZP) binding assay, combined with World Health Organization (WHO) grade 'a' sperm motility on the day of the IVF attempt, to predict sperm fertilizing ability in unexplained and moderate male factor infertilities.

METHODS

In total, 84 couples (64 unexplained infertility; 20 male factor) underwent both a sperm-ZP binding assay and an IVF attempt, irrespective of the test's result. The test was negative when grade 'a' motility was #5% and/or the ZP binding index was <0.7. Fertilization and pregnancy rates were related to the test's results.

RESULTS

Thirty-one patients had a negative test (group N) and 53 a positive test (group P). A difference was observed concerning the fertilization rate [median (range): 0 (0-75%) versus 50 (0-100%); P = 0.0001] and the number of cycles with fertilization rate <20% (65 versus 23%; P = 0.0002) between groups N and P respectively. In the group of unexplained and male factor infertilities, the test showed a sensitivity of 83 and 60%, specificity of 50 and 90%, positive predictive value of 76 and 86%, and negative predictive value of 61 and 69% respectively.

CONCLUSION

Sperm-ZP binding test, combined with WHO grade 'a' motility assessment, is relevant to prevent IVF fertilization failures in unexplained infertility and, most particularly, in moderate male factor infertility.

Optimal dynamic discrimination of similar quantum systems with time series data

Optimal dynamic discrimination (ODD) was proposed [Li et al., J. Phys. Chem. B 106, 8125 (2002)] as a paradigm for discriminating noninteracting similar quantum systems in a mixture. This paper extends the ODD concept to optimize a laser control pulse for guiding similar quantum systems such that each exhibits a distinct time series signal for maximum discrimination. The use of temporal data addresses various experimental difficulties, including noise in the laser pulse, signal detection errors, and finite time resolution in the signal. Simulations of ODD with time series data are presented to explore these effects. It is found that the use of an optimally chosen control pulse can significantly enhance the discrimination quality. The ODD technique is also adapted to the case where the sample contains an unknown background species.

Deciphering output coupling mechanisms in spiral microcavities with femtosecond light bullets

A pump-probe two-photon-excited fluorescence technique deciphers in space and time the propagation of ballistic wave packets sustained by whispering-gallery modes (WGMs) in a spiral-shaped microcavity. Diffraction on the spiral discontinuity does not prevent the WGMs from closing. The resultant average Q of the resonator is 3 x 10(4) +/- 50%. Experimental results are compared with numerical simulations, providing evidence of a new contribution to output coupling: Part of the WGM evanescent wave is reflected at the spiral notch and leads to a propagating wave at an angle that matches the previously observed laser emission direction in 4-dicyanomethylene-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran-doped poly(methyl methacrylate) and InGaN spiral lasers.

Leucospermie, stress oxydatif et fertilité masculine : certitudes et hypothèses

Leukocytospermia is frequent and significantly increased (over 10(6)/ml) in 20% of male factor infertility. It induces the production of highly toxic reactive oxygen species (ROS) which impair genital track accessory glands and sperm cell functions. The seminal medium contains extremely potent antioxidative defenses which usually balance the oxidative stress. In vivo, these defenses can be overwhelmed when ROS production is extremely important and/or when it lasts for a very long period of time. Infertility can then appear. In vitro, ROS have been univoqually demonstrated for being highly toxic since spermatozoa are no longer protected. Sperm cell defects are : decrease of acrosome reaction and fusiogenic ability and increase of DNA fragmentations. In case of male factor infertility, a leukocytospermia represents an essential or an additional risk factor that should be treated, specially when in vitro therapy is to be scheduled, in order to improve gamete quality.

Supercontinuum emission and enhanced self-guiding of infrared femtosecond filaments sustained by third-harmonic generation in air

The long-range propagation of two-colored femtosecond filaments produced by an infrared (IR) ultrashort pulse exciting third harmonics (TH) in the atmosphere is investigated, both theoretically and experimentally. First, it is shown that the coupling between the pump and TH components is responsible for a wide spectral broadening, extending from ultraviolet (UV) wavelengths (220 nm) to the mid-IR (4.5 microm). Supercontinuum generation takes place continuously as the laser beam propagates, while TH emission occurs with a conversion efficiency as high as 0.5%. Second, the TH pulse is proven to stabilize the IR filament like a saturable quintic nonlinearity through four-wave mixing and cross-phase modulation. Third, the filamentation is accompanied by a conical emission of the beam, which becomes enlarged at UV wavelengths. These properties are revealed by numerical simulations and direct experimental observations performed from the Teramobile laser facility.

Filamentation of femtosecond light pulses in the air: turbulent cells versus long-range clusters

The filamentation of ultrashort pulses in air is investigated theoretically and experimentally. From the theoretical point of view, beam propagation is shown to be driven by the interplay between random nucleation of small-scale cells and relaxation to long waveguides. After a transient stage along which they vary in location and in amplitude, filaments triggered by an isotropic noise are confined into distinct clusters, called "optical pillars," whose evolution can be approximated by an averaged-in-time two-dimensional (2D) model derived from the standard propagation equations for ultrashort pulses. Results from this model are compared with space- and time-resolved numerical simulations. From the experimental point of view, similar clusters of filaments emerge from the defects of initial beam profiles delivered by the Teramobile laser facility. Qualitative features in the evolution of the filament patterns are reproduced by the 2D reduced model.

Structural chromosomal mosaicism and prenatal diagnosis

True structural chromosomal mosaicism are rare events in prenatal cytogenetics practice and may lead to diagnostic and prognostic problems. Here is described the case of a fetus carrying an abnormal chromosome 15 made of a whole chromosome 2p translocated on its short arm in 10% of the cells, in association with a normal cell line. The fetal karyotype was 46,XX,add(15)(p10).ish t(2;15)(p10;q10)(WCP2+)[3]/46,XX[27]. Pregnancy was terminated and fetus examination revealed a growth retardation associated with a dysmorphism including dolichocephaly, hypertelorism, high forehead, low-set ears with prominent anthelix and a small nose, which were characteristic of partial trisomy 2p. Possible aetiologies for prenatal mosaicism involving a chromosomal structural abnormality are discussed.

Recombinant human LH supplementation during GnRH antagonist administration in IVF/ICSI cycles: a prospective randomized study

BACKGROUND

When administered in the late follicular phase to prevent an LH surge, GnRH antagonists induce a sharp decrease in serum LH levels that may be detrimental for assisted reproductive technology cycle outcome. Therefore, a prospective study was designed to assess the effects of recombinant human (r)LH supplementation during GnRH antagonist (cetrorelix) administration.

METHODS

The protocol consisted of cycle programming with oral contraceptive pill, ovarian stimulation with rFSH and flexible administration of a single dose of cetrorelix (3 mg). A total of 218 patients from three IVF centres were randomized (by sealed envelopes or according to woman's birth date) to receive (n = 114) or not (n = 104) a daily injection of rLH 75 IU from GnRH antagonist initiation to hCG injection.

RESULTS

The only significant difference was a higher serum peak E2 level in patients treated with rLH (1476 +/- 787 versus 1012 +/- 659 pg/ml, P < 0.001) whereas the numbers of oocytes and embryos as well as the delivery rate (25.2 versus 24%) and the implantation rate per embryo (19.1 versus 17.4%) were similar in both groups.

CONCLUSIONS

These results show that in an unselected group of patients, there is no evident benefit to supplement GnRH antagonist-treated cycles with rLH.

Multiple filamentation of terawatt laser pulses in air

The filamentation of femtosecond light pulses in air is numerically and experimentally investigated for beam powers reaching several TW. Beam propagation is shown to be driven by the interplay between intense, robust spikes created by the defects of the input beam and random nucleation of light cells. Evolution of the filament patterns can be qualitatively reproduced by an averaged-in-time (2D+1)-dimensional model derived from the propagation equations for ultrashort pulses.

Short-term vasomotor adjustments to post immersion dehydration are hindered by natriuretic peptides

Many studies have described the physiology of water immersion (WI), whereas few have focused on post WI physiology, which faces the global water loss of the large WI diuresis. Therefore, we compared hemodynamics and vasomotor tone in 10 trained supine divers before and after two 6h sessions in dry (DY) and head out WI environments. During each exposure (DY and WI) two exercise periods (each one hour 75W ergometer cycling) started after the 3rd and 5th hours. Weight losses were significant (-2.24 +/- 0.13 kg and -2.38 +/- 0.19 kg, after DY and WI, respectively), but not different between the two conditions. Plasma volume was reduced at the end of the two conditions (-9.7 +/- 1.6% and -14.7 +/- 1.6%, respectively; p < 0.05). This post-WI decrease was deeper than post DY (p < 0.05). Cardiac output (CO) and mean arterial blood pressure were maintained after the two exposures. Plasma levels of noradrenaline, antidiuretic hormone and ANP were twofold higher after WI than after DY (p < 0.05). After DY total peripheral resistances (TPR) were increased (p < 0.05) and heart rate (HR) was reduced (p < 0.05). After WI there was a trend for a decrease in stroke volume (p = 0.07) with unchanged TPR and HR, despite more sizeable increases in plasma noradrenaline and vasopressin than after DY. We hypothesized that the higher levels of plasma natriuretic peptides after WI were likely counteracting the dehydration-required vasomotor adjustments.

Maturation in vitro des ovocytes : bilan et perspectives dans l’espèce humaine

Mature oocytes are rare and highly specialized cells. In vitro maturation of human oocytes is an emerging assisted reproductive technology allowing to produce more mature oocytes without ovarian stimulation. Whereas in vitro maturation is technically more demanding than conventional in vitro fertilization for the laboratory, it carries many potential advantages, for example, in terms of lower treatment heaviness and removal of risk of severe ovarian hyperstimulation syndrome for the patients. Although the technology is still experimental, oocytes in vitro maturation has been successfully used and pregnancies and live births have been reported. Despite these successes, the overall efficiency of in vitro maturation remains low and this procedure must still be improved. The different steps of in vitro maturation process are shown and discussed as well as results in terms of pregnancy and live birth rates.