Directed, Elliptic, and Higher Order Flow Harmonics of Protons, Deuterons, and Tritons in Au+Au Collisions at sqrt[s_{NN}]=2.4 GeV.

Flow coefficients v_{n} of the orders n=1-6 are measured with the High-Acceptance DiElectron Spectrometer (HADES) at GSI for protons, deuterons, and tritons as a function of centrality, transverse momentum, and rapidity in Au+Au collisions at sqrt[s_{NN}]=2.4 GeV. Combining the information from the flow coefficients of all orders allows us to construct for the first time, at collision energies of a few GeV, a multidifferential picture of the angular emission pattern of these particles. It reflects the complicated interplay between the effect of the central fireball pressure on the emission of particles and their subsequent interaction with spectator matter. The high precision information on higher order flow coefficients is a major step forward in constraining the equation of state of dense baryonic matter.

Strong Absorption of Hadrons with Hidden and Open Strangeness in Nuclear Matter.

We present the first observation of K^{-} and ϕ absorption within nuclear matter by means of π^{-}-induced reactions on C and W targets at an incident beam momentum of 1.7 GeV/c studied with HADES at SIS18/GSI. The double ratio (K^{-}/K^{+})_{W}/(K^{-}/K^{+})_{C} is found to be 0.319±0.009(stat)_{-0.012}^{+0.014}(syst) indicating a larger absorption of K^{-} in heavier targets as compared to lighter ones. The measured ϕ/K^{-} ratios in π^{-}+C and π^{-}+W reactions within the HADES acceptance are found to be equal to 0.55±0.04(stat)_{-0.07}^{+0.06}(syst) and to 0.63±0.06(stat)_{-0.11}^{+0.11}(syst), respectively. The similar ratios measured in the two different reactions demonstrate for the first time experimentally that the dynamics of the ϕ meson in nuclear medium is strongly coupled to the K^{-} dynamics. The large difference in the ϕ production off C and W nuclei is discussed in terms of a strong ϕN in-medium coupling. These results are relevant for the description of heavy-ion collisions and the structure of neutron stars.

Subthreshold Ξ

Results on the production of the double strange cascade hyperon Ξ^{-} are reported for collisions of p(3.5 GeV)+Nb, studied with the High Acceptance Di-Electron Spectrometer (HADES) at SIS18 at GSI Helmholtzzentrum for Heavy-Ion Research, Darmstadt. For the first time, subthreshold Ξ^{-} production is observed in proton-nucleus interactions. Assuming a Ξ^{-} phase-space distribution similar to that of Λ hyperons, the production probability amounts to P_{Ξ^{-}}=[2.0±0.4(stat)±0.3(norm)±0.6(syst)]×10^{-4} resulting in a Ξ^{-}/(Λ+Σ^{0}) ratio of P_{Ξ^{-}}/P_{Λ+Σ^{0}}=[1.2±0.3(stat)±0.4(syst)]×10^{-2}. Available model predictions are significantly lower than the measured Ξ^{-} yield.

Deep subthreshold Xi;{-} production in Ar + KCl reactions at 1.76A GeV.

We report first results on a deep subthreshold production of the doubly strange hyperon Xi;{-} in a heavy-ion reaction. At a beam energy of 1.76A GeV the reaction Ar + KCl was studied with the High Acceptance Di-Electron Spectrometer at SIS18/GSI. A high-statistics and high-purity Lambda sample was collected, allowing for the investigation of the decay channel Xi;{-} --> Lambdapi;{-}. The deduced Xi;{-}/(Lambda + Sigma;{0}) production ratio of (5.6 +/- 1.2_{-1.7};{+1.8}) x 10;{-3} is significantly larger than available model predictions.

[In vitro fertilization at the Erasme Hospital: 10 years and 1000 pregnancies later...]. / La fecondation in vitro a l'Hopital Erasme: 10 ans et 1000 grossesses plus tard....

This contribution summarize ten years of in vitro fertilization of clinical work. Activity growth, improvements of results (mean fertilization rate increased from 45% to 58%, fertilization failure dropped from 18% to 7%, pregnancy chances gains 9% to reach 44% per trial) and new treatments possibilities (severe male infertility) thanks to the ICSI technic were the major characteristics of this last ten years. The original anonymous oocyte donation program with donors permutation initiated as soon as 1990 has imposed itself due to it's exceptional efficiency with a pregnancy rate of 95% per oocyte pick up on a population of 46 donors and 145 recipient cycles. Thanks to the large population studied (4028 cycles, 1071 pregnancies), the tendencies in human fecundity (impact of age) and the risks linked to multiples pregnancies could be highlighted, stressing the importance of future developments presented in the other contributions following this general presentation of results.

[Evolution of ovarian stimulation in in vitro fertilization]. / Evolution de la stimulation ovarienne en fecondation in vitro.

This paper reviews the different treatments of ovarian stimulation for in vitro fertilization (IVF). It emphasizes the recent development of new molecules, including recombinant gonadotrophins and GnRH antagonists. Because of their higher purity, recombinant gonadotrophins are theoretically less immunogenic than the urinary forms. Their preparation mode ensures a better batch to batch consistency. Their clinical use in IVF seems to be associated with a higher number of developing follicules and retrieved oocytes, but pregnancy rates are comparable to those obtained after ovarian stimulation with urinary gonadotrophins. The GnRH antagonists induce a direct inhibition of the pituitary gonadotrophin secretion. In association with an ovarian stimulation with gonadotrophins, they efficiently prevent premature LH surges when administered during the end of the follicular phase. The GnRH antagonists are still in clinical evaluation phase and the optimal protocol and dose still to be defined. They should become available in the coming year. The risks related to the controlled hyperstimulation together with the reduction of the number of transferred embryos has recently led "soft stimulation" to a reevaluation of the stimulation protocols towards a simplified procedure. However, the validity of this attitude could be in opposition with the wish to limit the number of transferred embryos since embryo quality seems to be directly related to the total number of embryos.

Comparison of pregnancy outcome after intracytoplasmic sperm injection and in-vitro fertilization.

The aim of this study was to compare pregnancy characteristics and perinatal outcome of intracytoplasmic sperm injection (ICSI) pregnancies with pregnancies obtained after in-vitro fertilization (IVF). Retrospectively, 145 ICSI pregnancies were matched with 145 IVF pregnancies using the last menstruation data. The main outcome measures were preclinical and clinical abortions, ectopic pregnancies, multiple gestations, prenatal morbidity, prematurity, Caesarean section, birthweight, perinatal mortality and malformations for singletons, twins and triplets. Although patients were significantly younger (P < 0.001) in ICSI (31 years) than in IVF (33 years), their infertility duration (5 years) was similar. The mean number of transferred embryos (2.7 embryos per transfer) was similar in IVF and ICSI. The rates of preclinical (15%) and clinical abortions (11% in ICSI versus 15% in IVF) were not different. Four ectopic pregnancies were observed in the IVF group and none in the ICSI group. In ICSI, two minor malformations were detected and two therapeutic abortions were performed respectively for polymalformations and suspicion of cystic fibrosis. The rate of congenital malformation was 2.8% in ICSI and 2.2% in IVF. In this last group, one therapeutic abortion for malformation of neural tube was performed and two minor malformations were detected. The rate of aborted embryonic sacs before 16 weeks of gestation was not significantly lower in ICSI compared with IVF (13.7% versus 20%). The rate of multiple gestations was similar in both groups (31% in IVF and 35% in ICSI). The number of Caesarean sections was similar in IVF and in ICSI and was twice as frequent for twins versus singletons. The number of singletons born by Caesarean section was 21% after ICSI and 17% after IVF. Mean birthweights and gestational ages at birth for twins were significantly higher (P < 0.05) in ICSI than in IVF (2488 versus 2281 g and 36.5 versus 35.5 weeks). This difference was not observed for singletons. In conclusion, pregnancy characteristics and perinatal outcome after ICSI showed no increase in the number of pathologies in comparison with IVF.

Is intracytoplasmic sperm injection (ICSI) a safe procedure? What do we learn from early pregnancy data about ICSI?

The aim of this study was to evaluate the safety of the intracytoplasmic sperm injection (ICSI) procedure by analysing early pregnancy data from ICSI and in-vitro fertilization (IVF) patients. In all, 50 ICSI pregnancies were compared with 226 IVF pregnancies. Comparisons were made during the first 9 weeks after the theoretical last menstrual period (7 weeks after oocyte retrieval) with regard to epidemiological data, plasma hormonal concentrations and transvaginal ultrasonographical findings. Although patients were significantly (P < 0.001) younger in ICSI (31 years) than in IVF pregnancies (33 years), their duration of infertility was similar. Miscarriage and multiple gestation rates were not significantly different in ICSI pregnancies (respectively 24 and 24%) from those found after IVF (32 and 29%). The probability of developmental arrest of the intrauterine sac (miscarriages and vanishing twins) was similar in both ICSI (16%) and IVF (25%) cases. The mean plasma hormonal concentrations starting from day 11 after oocyte retrieval were similar in both groups. Every ICSI and IVF pregnancy showed an embryo with cardiac activity at 7 weeks. Early pregnancy data did not show any abnormal findings for pregnancies achieved using ICSI compared to those achieved by IVF.

[Preclinical trials for mastering intracytoplasmic injection of a sole spermatozoid for the treatment of male infertility]. / Des essais précliniques à la maîtrise de l'injection intracytoplasmique d'un seul spermatozoïde (ICSI) pour le traitement de la stérilité masculine.

Before starting with the clinical application of ICS, aged unfertilized oocytes were gathered for training and were injected with a single sperm or without a spermatozoon as a control group for activation. Oocyte damage, initially as high as 40% was reduced to 15% after 60 oocytes. Normal fertilization (2PN) occurred in 18% of the injected oocytes. After this training period 1,488 metaphase II oocytes collected during 144 cycles were used for ICSI. Results were split up in 3 periods (n = 55, n = 24, n = 57) corresponding to the different improvements made in the technique. Results form ICSI in combination with MESA (n = 6) were analysed separately. Mean fertilization increased from 24% to 77%. Fertilization failures (18% of the cycles during the first period) vanished in the last period. Implantation rate improved from 7.4% to 11.4% and reached finally 26%. Pregnancy rate per oocyte retrieval was 16%, 25% and 54%. For the MESA group fertilization was 28%, implantation rate 17% and pregnancy rate 33% and only one fertilization failure was observed. A total of 50 pregnancies were obtained including 2 obtained after MESA and 2 with cryopreserved embryos. Four healthy children are born, 9 were early abortions, 37 pregnancies are still on-going. Preclinical practice on aged unfertilized oocytes seems useful before starting with clinical ICSI, as high initial oocyte damage could be reduced and subsequent clinical treatment successfully applied. Offering high fertilization and pregnancy rates in cases of infertility with severe male factor it is extremely worthwhile mastering this new technique.

Functional analysis of the signal-sequence processing site of yeast acid phosphatase.

A systematic study of the signal peptidase cleavage site of the main cell-wall-repressible Saccharomyces cerevisiae acid phosphatase encoded by the PHO5 gene is presented. The last amino acid of the signal sequence, the chromosomally encoded alanine of the wild-type gene, was changed by any of 19 other amino acids in the chromosomal DNA by using in vitro mutagenesis in Escherichia coli and the technique of gene replacement. Processing and secretion are normal when the amino acid at this position is a small neutral amino acid, i.e. alanine, glycine, cysteine, serine or threonine. Processing glycosylation, and secretion of regulated acid phosphatase are distinctly affected with other amino acid substitutions and core-glycosylated protein accumulates in the cell. Surprisingly, PHO5 protein is still secreted to the cell wall and into the growth medium but at a lower rate and without cleavage of the signal sequence. The same features are exhibited by a mutated acid phosphatase with a deletion of four amino acids at the end of the signal peptide (-7 to -4 relative to the processing site) thus preserving the important -3 to -1 region.

Untargeted mutagenesis induced by UV in the lacI gene of Escherichia coli.

Using a nonselective method, we have estimated the proportion of untargeted mutations in the lacI gene of E. coli by transferring either irradiated or unirradiated F' pro lac plasmids from an excision deficient donor to an excision deficient pro lac deleted recipient that had been irradiated and allowed to induce recA dependent functions for 30 min. We find that about 10 percent of the mutations induced by either 3.5 Jm-2 or 7 Jm-2 UV are untargeted.

A second cauliflower mosaic virus gene product influences the structure of the viral inclusion body.

We have used electron microscopy of thin sections and experiments on isolated viroplasms to compare the properties of four strains of cauliflower mosaic virus (CaMV), three of which were partially or completely deleted in open reading frame (ORF) II. Our results confirm that this gene is required for aphid transmissibility and show that the product of ORF II influences the firmness with which virions are held within the viroplasm. Analysis of the proteins in the viroplasms showed that a mutant with a partial deletion in ORF II produced a protein smaller than the normal ORF product. This smaller protein was non-functional with respect both to aphid transmissibility and properties of the viroplasms.

Mutagenesis of cauliflower mosaic virus.

A series of insertion mutants of cauliflower mosaic virus (CaMV) DNA has been constructed in vitro. These insertions consist of a short DNA sequence (10 or 22 bp) containing a restriction endonuclease site (SmaI) not represented on the viral DNA. Viral infectivity was analyzed by inoculating plants with the mutated cloned viral DNA and observing symptoms. Insertions within ORFVII, and in one site within the large intergenic region, did not interfere with viral infectivity, whilst insertions within ORFII and at the end of ORFIV retarded the development of viral symptoms. All other insertion mutants analyzed were lethal. CaMV with a deletion of 105 bp within ORFVII was viable. Such viable mutants can be used to construct additional deletions or to insert foreign DNA into the viral genome.