Biomedical subjects

J P Wolf

Publications and source records attributed to J P Wolf.

At least 19 recordsLinked to original sources

PubMed2006

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.

Adult↗

PubMed2006

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.

Adult↗

PubMed2006

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.

Administration, Cutaneous↗

PubMed2006

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.

Journal Article↗

PubMed2005

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.

ADAM Proteins↗

PubMed2005

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.

Adult↗

PubMed2005

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.

Journal Article↗

PubMed2005

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.

Journal Article↗

PubMed2005

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.

Journal Article↗

PubMed2004

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.

Journal Article↗

PubMed2004

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.

Adult↗

PubMed2004

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.

Journal Article↗

PubMed2004

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.

Abnormalities, Multiple↗

PubMed2004

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.

Adult↗

PubMed2003

White-light filaments for atmospheric analysis.

Most long-path remote spectroscopic studies of the atmosphere rely on ambient light or narrow-band lasers. High-power femtosecond laser pulses have been found to propagate in the atmosphere as dynamically self-guided filaments that emit in a continuum from the ultraviolet to the infrared. This white light exhibits a directional behavior with enhanced backward scattering and was detected from an altitude of more than 20 kilometers. This light source opens the way to white-light and nonlinear light detection and ranging applications for atmospheric trace-gas remote sensing or remote identification of aerosols. Air ionization inside the filaments also opens promising perspectives for laser-induced condensation and lightning control. The mobile femtosecond-terawatt laser system, Teramobile, has been constructed to study these applications.

Journal Article↗

PubMed2003

[Oocytes in vitro maturation: results and future in humans].

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.

Cell Culture Techniques↗

PubMed2002

[Consequences of oocyte dysmorphy on the fertilization rate and embryo development after intracytoplasmic sperm injection. A prospective multicenter study].

OBJECTIVES: This prospective study aimed to evaluate the impact of oocyte dysmorphy on the fertilization rate and embryonic development rate in an ICSI programme. PATIENTS AND METHODS: Three hundred and two couples have been included during 302 ICSI cycles, and 1970 oocytes have been studied in 4 ART centres. After decoronisation, 18 morphological criteria, including the size and shape of the oocyte, the thickness of the zona pellucida, the presence or not of debris in the perivitelline space, as well as the appearance of the cytoplasm and polar body have been noted. RESULTS: In total 61.3% of the oocytes presented a dysmorphy, involving, almost equally, the different oocyte compartments. Among the dysmorphic oocytes, half presented more than one anomaly. On average, 9.2% of the oocytes were lysed the day after the micro-injection. The oocytes presenting an enlarged perivitelline space, or multiple vacuoles had a significantly raised lyse rate, 16.3% and 27.8%, respectively. The day after micro-injection, 61.3% of the intact oocytes were fertilized. The rate of fertilization was correlated to the number of abnormalities per oocyte: 1 anomaly: 64.6%, > or = 3 anomalies: 54.6%. The oocytes presenting a large perivitelline space had a slightly lowered fertilization rate (53.4%). On the other hand, those showing a cytoplasm containing refractile bodies had a slightly raised fertilization rate (68.6%). We did not see any statistically significant difference between the different types of oocytes concerning embryonic development at d2. CONCLUSION: These results confirm and contribute new elements with respect to previously published data, showing that (i) oocyte morphology little affects fertilization and the first stages of embryonic development; (ii) certain dysmorphies, (enlargement of the perivitelline space) are specifically deleterious at certain stages in the process (lowering the fertilization rate); (iii) certain morphological differences (the presence of refringent bodies) are not anomalies, but can reflect physiological cellular changes.

Cell Size↗

PubMed2002

Lack of submicroscopic rearrangements involving telomeres in reproductive failures.

BACKGROUND: It has been recognized that chromosomal abnormalities are one of the most important causes of the high mortality rate in human concepti. Among these abnormalities, the unbalanced transmission of a parental chromosomal rearrangement is frequently observed, and couples with a history of pregnancy losses are therefore referred for genetic counselling and to establish their karyotype. Unbalanced chromosomal rearrangements involving telomeres are emerging as an important cause of mental retardation and/or congenital malformations in humans. As suggested by several authors, they could also be responsible for recurrent miscarriages. The aim of this study was to screen cryptic chromosome abnormalities in couples referred to our laboratory for recurrent unexplained miscarriages. METHODS AND RESULTS: Karyotyping was performed in 57 couples (114 patients). A detectable chromosomal abnormality was diagnosed in seven cases, thus limiting the analysis of telomeres to only 100 patients. Two different protocols were used according to the number of metaphases on slides. No telomeric chromosome abnormality was detected in our study. CONCLUSION: The use of FISH telomeric probes is not of clinical interest in the systematic screening of couples with multiple miscarriages and should be performed only in those with a familial history of mental retardation and congenital malformations.

Abortion, Habitual↗