Immunofluorescence study of actin, acrosin, dynein, tubulin and hyaluronidase and their impact on in-vitro fertilization

Using polyclonal antibodies, the distribution of actin, acrosin, dynein, tubulin and hyaluronidase has been examined by indirect immunofluorescence in sperm preparations from fertile donors and in-vitro fertilization (IVF) patients. After recording sperm parameters in native semen, spermatozoa were washed free of seminal plasma using either the swim-up or the Percoll filtration technique. Prior to insemination, aliquots of the washed sperm suspensions were prepared for antibody staining. Spermatozoa from fertile donors were analysed in order to establish the specific fluorescence patterns of each antibody and the threshold scores of normality. Immunofluorescence scores obtained from IVF patients were then analysed with respect to IVF outcome. For each tested protein, the number of normal samples were significantly lower in the group which did not fertilize and fertilization rates were significantly reduced when any of the tested proteins were scored as pathological. Normal fluorescence scores were correlated with morphology, motility, velocity and to a lesser extent with sperm concentration in native semen. On the basis of receiver-operating characteristic curves, likelihood ratios and Cohen's kappa values, the presence of acrosin and tubulin yields the most useful information on sperm functional and structural status and on its fertilizing abilit

Morphological scoring of human pronuclear zygotes for prediction of pregnancy outcome

BACKGROUND: As embryo selection is not allowed by law in Switzerland, we need a single early scoring system to identify zygotes with high implantation potential and to select zygotes for fresh transfer or cryopreservation. The underlying aim is to maximize the cumulated pregnancy rate while limiting the number of multiple pregnancies. METHODS: In all, 613 fresh and 617 frozen-thawed zygotes were scored for proximity, orientation and centring of the pronuclei, cytoplasmic halo, and number and polarization of the nucleolar precursor bodies. From these individual scores, a cumulated pronuclear score (CPNS) was calculated. Correlation between CPNS and implantation was examined and compared between fresh and frozen-thawed zygotes. The effect of freezing on CPNS was also investigated. RESULTS: CPNS was positively associated with embryo implantation in both fresh and frozen zygotes. With similar CPNS, frozen zygotes presented implantation rates as high as those of fresh zygotes. Nucleolar precursor bodies pattern and cytoplasmic halo appeared as the most important factors predictive of implantation for both types of zygotes, while pronuclei position was specifically relevant for frozen-thawed zygotes. Freezing induced an alteration of most zygote parameters, resulting in a significantly lower CPNS and a lower pregnancy rate. CONCLUSIONS: CPNS may be used as a single prognostic tool for implantation of both fresh and frozen-thawed zygotes. Lower CPNS values of frozen-thawed zygotes may also be indicative of freezing damage to zygotes. Successful implantation of frozen zygotes despite lower CPNS suggests that they may recover after thawing and in vitro cultur

Aorto-subclavian thromboembolism: a rare complication associated with moderate ovarian hyperstimulation syndrome

The case of an arterial aorto-subclavian thromboembolism associated with a moderate ovarian hyperstimulation syndrome (OHSS) and following ovulation induction for in-vitro fertilization in a young woman is reported. Because of the lack of response to systemic thrombolysis, a left postero-lateral thoracotomy was performed on day 8 after embryo transfer. A fibrinocruoric embolus situated at the junction of the left subclavian artery from the aorta was removed through a left subclavian arteriotomy. The distal axillary embolus was removed by a retrograde balloon catheter embolectomy. A moderate OHSS was observed. The ovarian stimulation and OHSS-related risks of thromboembolism are discussed. We conclude that, in the absence of risk factors, counselling about possible complications resulting from stimulation must be emphasize

What is the most relevant standard of success in assisted reproduction?: The cumulated singleton/twin delivery rates per oocyte pick-up: the CUSIDERA and CUTWIDERA

National and international registries are essential tools for establishing new standards and comparing success rates, but they do not take into account the total pregnancy/delivery rate per oocyte recovery. In Switzerland and Germany, because of legal constraints, a maximum of three two-pronuclear zygotes are allocated for transfer whereas all the supernumerary pronuclear zygotes are immediately cryopreserved, preventing selection of the transferred embryos. We report on a 10 years' experience (1993-2002) of our centre which performs transfers of unselected embryos and cryopreservation at the two-pronuclear zygote stage. As ∼30% of all deliveries are from cryo cycles, it is essential to take into account the contribution of the cryo transfers, and we propose therefore to evaluate, as a measure of IVF performance, the cumulated delivery rate per oocyte pick-up. This delivery rate is broken down further into the cumulated singleton delivery rate (CUSIDERA) and the cumulated twin delivery rate (CUTWIDERA). The sum (S) of these two rates is a measure of efficacy while the ratio CUTWIDERA/S as a percentage is a measure of safety of IVF treatments. Using these new indexes, the average 10 year efficacy and safety of our IVF programme were 26 and 19%, respectively. Both CUSIDERA and CUTWIDERA can be calculated easily in any clinical situation and yield useful parameters for patient counselling and internal/external benchmarking purpose

Antibrouillage radar en contexte de rotation d'antenne

- Nous nous intéressons dans cet article à l'algorithme Opposition dans les Lobes Secondaires (OLS) utilisé en traitement d'antenne RADAR dans un but d'antibrouillage en contexte de rotation d'antenne. Nous montrons que l'utilisation de la méthode Extended Sample Matrix Inversion (ESMI) [2] conduit alors à des performances supérieures à la méthode standard

Structural plasticity of single chromatin fibers revealed by torsional manipulation

Magnetic tweezers are used to study the mechanical response under torsion of single nucleosome arrays reconstituted on tandem repeats of 5S positioning sequences. Regular arrays are extremely resilient and can reversibly accommodate a large amount of supercoiling without much change in length. This behavior is quantitatively described by a molecular model of the chromatin 3-D architecture. In this model, we assume the existence of a dynamic equilibrium between three conformations of the nucleosome, which are determined by the crossing status of the entry/exit DNAs (positive, null or negative). Torsional strain, in displacing that equilibrium, extensively reorganizes the fiber architecture. The model explains a number of long-standing topological questions regarding DNA in chromatin, and may provide the ground to better understand the dynamic binding of most chromatin-associated proteins.Comment: 18 pages, 7 figures, Supplementary information available at http://www.nature.com/nsmb/journal/v13/n5/suppinfo/nsmb1087_S1.htm