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In this paper, chaotic dynamics of a cubic-quintic-septic Duffing oscillator subjected to periodic excitation is investigated. The multiple scales method is used to determine the various resonance states of the model. It is found that the considered model posses thirteen resonance states whose seven are thoroughly studied. The steady-state solutions and theirs stabilities are determined. The frequency-amplitude curves show that the considered system presents mixed behavior, limit cycles, hysteresis, jump and bifurcation phenomena. It is also noticed that these phenomena are strongly influenced by quintic-septic nonlinearity and excitation amplitude. Bifurcation structures displayed by the model for each considered type of resonant states are investigated numerically using the fourth-order Runge-Kutta algorithm. As results, the quintic-septic nonlinearity, linear dissipation and excitation amplitude can be used to control the chaotic behavior of the system.

The BRCA1-binding RING-finger domain protein BARD1 may act conjointly with BRCA1 in DNA repair and in ubiquitination, but it may also induce apoptosis in a BRCA1-independent manner. In this study, we have investigated BARD1 expression during spermatogenesis. In contrast with BRCA1, which is expressed only in meiotic spermatocytes and early round spermatids, BARD1 is expressed during all stages of spermatogenesis. However, while spermatogonia expressed full-length BARD1 mRNA, later stages of spermatocyte precursors express predominantly a novel, shorter splice form BARD1beta. BARD1beta lacks the BRCA1-interacting RING finger but maintains its proapoptotic activity. Consistently, BRCA1 can counteract the proapoptotic activity of full-length BARD1 but not of BARD1beta. Several lines of evidence suggest that BARD1 is involved in proapoptotic signaling in testis: i) both BARD1 isoforms are mostly found in cells that stain positive for TUNEL, Bax, and activated caspase 3; ii) BARD1beta, capable of inducing apoptosis even in the presence of BRCA1, is specifically expressed in BRCA1-positive later stages of spermatogenesis; iii) antiapoptotic hormonal stimulation leads to BARD1 downregulation; and iv) BARD1 expression is associated with human pathologies causing sterility due to increased germ cell death. Our data suggest that full-length BARD1 might be involved in apoptotic control in spermatogonia and primary spermatocytes, while a switch to the BRCA1-independent BARD1beta might be necessary to induce apoptosis in BRCA1-expressing meiotic spermatocytes and early round spermatids.

New high pressure Raman spectroscopy measurements on pure anhydrous HNO{sub 3} and HNO{sub 3}-H{sub 2}O mixtures up to 38 mol% in water (commercial grade concentration) are reported up to 50 GPa. The main feature is the reversible and progressive transformation of pure solid nitric acid at pressures between 10 and 17 GPa, evidenced by an enhancement of the 1,057 cm{sup {minus}1} peak assigned to the {nu}{sub 1} vibrational stretching mode of the NO{sub 3}{sup {minus}} group and by the softening of the symmetric stretching NO{sub 2} mode with pressure. The formation of the H bonding by a charge transfer due to a strong interaction between the surrounding molecules is discussed. Two hypotheses are discussed: nitric acid might be pressure autoionized or cross-linked as a reversible polymer-like compound. These two hypotheses are not mutually exclusive. An increase of water concentration in nitric acid shifts the limit of the appearance of the NO{sub 3}{sup {minus}} vibrational mode to lower values of the pressure at constant temperature.

Background Externalization of phosphatidylserine (EPS) occurs in apoptotic-like spermatozoa and could be used to remove them from sperm preparations to enhance sperm quality for assisted medical procreation. We first characterized EPS in sperms from infertile patients in terms of frequency of EPS spermatozoa as well as localization of phosphatidylserine (PS) on spermatozoa. Subsequently, we determined the impact of depleting EPS spermatozoa on sperm quality. Methods EPS were visualized by fluorescently-labeled annexin V binding assay. Double staining with annexin V and Hoechst differentiates apoptotic from necrotic spermatozoa. We used magnetic-activated cell sorting using annexin V-conjugated microbeads (MACS-ANMB) technique to remove EPS spermatozoa from sperm prepared by density gradient centrifugation (DGC). The impact of this technique on sperm quality was evaluated by measuring progressive motility, viability, and the integrity of the mitochondrial membrane potential (MMP) by Rhodamine 123. Results Mean percentages of EPS spermatozoa were 14% in DGC sperm. Four subpopulations of spermatozoa were identified: 70% alive, 3% early apoptotic, 16% necrotic and 11% late apoptotic or necrotic. PS were localized on head and/or midpiece or on the whole spermatozoa. MACS efficiently eliminates EPS spermatozoa. MACS combined with DGC allows a mean reduction of 70% in EPS and of 60% in MMP-disrupted spermatozoa with a mean increase of 50% in sperm survival at 24 h. Conclusion Human ejaculates contain EPS spermatozoa which can mostly be eliminated by DGC plus MACS resulting in improved sperm long term viability, motility and MMP integrity. EPS may be used as an indicator of sperm quality and removal of EPS spermatozoa may enhance fertility potential in assisted medical procreation.

The BRCA1-binding RING-finger domain protein BARD1 may act conjointly with BRCA1 in DNA repair and in ubiquitination, but it may also induce apoptosis in a BRCA1-independent manner. In this study, we have investigated BARD1 expression during spermatogenesis. In contrast with BRCA1, which is expressed only in meiotic spermatocytes and early round spermatids, BARD1 is expressed during all stages of spermatogenesis. However, while spermatogonia expressed full-length BARD1 mRNA, later stages of spermatocyte precursors express predominantly a novel, shorter splice form BARD1beta. BARD1beta lacks the BRCA1-interacting RING finger but maintains its proapoptotic activity. Consistently, BRCA1 can counteract the proapoptotic activity of full-length BARD1 but not of BARD1beta. Several lines of evidence suggest that BARD1 is involved in proapoptotic signaling in testis: i) both BARD1 isoforms are mostly found in cells that stain positive for TUNEL, Bax, and activated caspase 3; ii) BARD1beta, capable of inducing apoptosis even in the presence of BRCA1, is specifically expressed in BRCA1-positive later stages of spermatogenesis; iii) antiapoptotic hormonal stimulation leads to BARD1 downregulation; and iv) BARD1 expression is associated with human pathologies causing sterility due to increased germ cell death. Our data suggest that full-length BARD1 might be involved in apoptotic control in spermatogonia and primary spermatocytes, while a switch to the BRCA1-independent BARD1beta might be necessary to induce apoptosis in BRCA1-expressing meiotic spermatocytes and early round spermatids.

Objective: Premenstrual dysphoric disorder (PMDD), also referred to as premenstrual syndrome (PMS), is a recurrent luteal-phase condition involving regular occurrence, prior to the onset of menstrual bleeding, of a cluster of symptoms of sufficient severity to result in the deterioration of interpersonal relationships and normal activity. Several treatment options for PMDD with varying degrees of efficacy have been proposed. The literature is reviewed and treatments of proven efficacy are reported. Study design and methods: A MEDLINE/ Cochrane Library search for all studies on PMS and PMDD published between 1983 and 2001 was performed. Only randomised trials were included. Results: Several treatments appear to be effective. Among these are increased physical activity, dietary change, mineral salt supplementation and ovulation inhibitors. The most effective seems to be administration of selective inhibitors of serotonin reuptake (SSRIs). Conclusion: Therapy should begin with non-medicated approaches and pharmacological treatment should only be envisaged if symptoms persist.

Patients with hydrosalpinges show a decrease of both fertility and clinical outcome of IVF and embryo transfer treatment. Several reports have demonstrated the negative effects of hydrosalpinx fluid (HSF) on embryo development and implantation. The aim of this study was to determine whether human HSF, collected from infertile patients, might exhibit a deleterious effect on gametes and fertilization using a murine IVF system. Murine gametes were co-incubated during IVF until first cleavage with human HSF diluted to 50% from four patients (HSF1-4). It was demonstrated that HSF affected fertilization, as determined by the count of the 2-cell embryos. Pre-incubation of spermatozoa with HSF during capacitation significantly lowered the percentage of 2-cell embryos (P < 0.05). While HSF1-3 had no significant effect on motility and viability of spermatozoa, HSF4 almost completely affected their survival. In contrast, pre-incubation of ovulated oocytes surrounded by their cumulus cells with HSF before IVF did not impede first cleavage. Taken together, these results suggest that HSF has a cytotoxic effect on spermatozoa and/or impairs the fertilization process, probably by altering capacitation/acrosome reaction and/or ligand(s)-receptor(s) interactions. Hydrosalpinges may be partly associated with sterility through HSF inhibitory effects on fertilization.

Objective: To report on a novel, accurate method for detecting microdeletion involving the DAZ gene in infertile men. Design: Retrospective clinical study. Setting: University Infertility Center of Cochin Hospital, Paris, France. Patient(s): Infertile patients (n = 25) consulting our infertility department during 1998. The patient cohort included subjects with nonobstructive azoospermia and oligoasthenospermia. Intervention(s): Blood samples were collected from each subject. Main Outcome Measure(s): DNA analysis using polymerase chain reaction (PCR)–denaturing gradient gel electrophoresis (DGGE). Result(s): We used a new molecular genetic strategy to rapidly identify deletions of the Y chromosome that include the DAZ locus. The experiment consists of amplifying simultaneously exon 4 of the DAZ and DAZLA genes with the use of specific primers that are complementary to intronic sequences of these genes. DGGE was used to separate the two PCR products, with good resolution. In infertile men with a microdeletion of the DAZ gene, this method allows amplification of an internal control when a deletion of that portion of the Yq chromosome is observed on a single amplification. Conclusion(s): This PCR-DGGE method for detection of DAZ gene deletion is simple and fast and does not require the use of radioactive elements. Compared with the classic PCR approach, this new method allows the amplification of the DAZLA copy to be used as an effective internal control in infertile men with microdeletion of the DAZ locus. This procedure could be particularly useful in screening for the DAZ locus in the diagnostic workup of nonobstructive azoospermia and severe oligoasthenoteratozoospermia.