Spermine biphasically affects N-type calcium channel currents in adult dorsal root ganglion neurons of the rat.

Spermine (Spe) is a polyamine co-secreted with neurotransmitters. In this work its effects on N-type Ca2+ channel (CaV2.2) have been studied on adult sensory neurons of the rat by means of whole-cell patch-clamp. Spe exerted biphasic effects when added to the external solution: at 500 microM decreased N-type Ca2+ channel currents, reducing the maximum whole-cell conductance, shifting the activation curve to the right on the voltage axes and decreasing its slope; conversely, at lower concentration (500 nM) Spe induced completely opposite effects. In 62% of the neurons the inhibitory effects were accompanied by a slowing down of the activation kinetics relieved by a conditioning pre-pulse to +50 mV. The biphasic effects and their rapid onset and offset time course may be explained if multiple sites of action with a different affinity for Spe are present directly on the channel. The effects of Spe on HVA Ca2+ currents were strongly dependent on [Ca2+]ext, high [Ca2+] powerfully reducing Spe effects. This may be explained if we take into account that as Spe has four positive charges at physiological pH; it may compete with divalent cations for some negatively charged regulatory sites. In these experiments, Spe was effective at concentrations possibly reached in physiological conditions.

Myo-inositol in patients with polycystic ovary syndrome: a novel method for ovulation induction.

BACKGROUND: Polycystic ovary syndrome (PCOS) is often characterized by chronic oligo- or anovulation (usually manifested as oligo- or amenorrhea), and hyperandrogenism. In addition, 30-40% of PCOS women have impaired glucose tolerance, and a defect in the insulin signaling pathway (inositol-containing phosphoglycan mediators) seems to be implicated in the pathogenesis of insulin resistance. PCOS patients are subfertile as a consequence of such ovulatory disorders and often need drugs, such as clomiphene citrate or follicle-stimulating hormone, for ovulation induction, which increases the risk of multiple pregnancy and ovarian hyperstimulation syndrome. We hypothesized that the administration of an isoform of inositol (myo-inositol), belonging to the vitamin B complex, would improve the insulin-receptor activity, restoring normal ovulatory function. MATERIALS AND METHODS: Twenty-five PCOS women of childbearing age with oligo- or amenorrhea were enrolled in the study. Ovulatory disorder due to PCOS was apparently the only cause of infertility; no tubal defect or deficiency of male semen parameters was found. Myo-inositol combined with folic acid (Inofolic) 2 g twice a day was administered continuously. During an observation period of 6 months, ovulatory activity was monitored with ultrasound scan and hormonal profile, and the numbers of spontaneous menstrual cycles and eventually pregnancies were assessed. RESULTS: Twenty-two out of the 25 (88%) patients restored at least one spontaneous menstrual cycle during treatment, of whom 18 (72%) maintained normal ovulatory activity during the follow-up period. A total of 10 singleton pregnancies (40% of patients) were obtained. Nine clinical pregnancies were assessed with fetal heart beat at ultrasound scan. Two pregnancies evolved in spontaneous abortion. CONCLUSION: Myo-inositol is a simple and safe treatment that is capable of restoring spontaneous ovarian activity and consequently fertility in most patients with PCOS. This therapy did not cause multiple pregnancy.

Natural cycle as first approach in aged patients with elevated follicle-stimulating hormone undergoing intracytoplasmic sperm injection: a pilot study.

BACKGROUND: Poor ovarian response to standard in vitro fertilization-embryo transfer (IVF-ET) protocols or different regimens of treatment, as consequence of a diminished ovarian reserve, correlates strictly with patient age, elevated follicle-stimulating hormone (FSH) and reduced antral follicle count. The aim of the present pilot study was to evaluate the outcome of patients with poor prognostic features undergoing IVF-ET with natural cycles as a first approach and not as a consequence of a previous failure treatment. MATERIALS AND METHODS: Eighteen aged patients (mean +/- standard deviation 40.2 +/- 0.7 years, range 37-43 years) with elevated serum FSH and reduced antral follicle count underwent intracytoplasmic sperm injection (ICSI) after spontaneous ovulation. RESULTS: A total of 26 natural cycles with ICSI were analyzed. Pregnancy was observed in three patients, of which two were ongoing as assessed by fetal heart beat at ultrasound scan performed 4-5 weeks after ET. CONCLUSION: The overall pregnancy rates achieved (11.5% per cycle, 20.0% per ET) are comparable with those of conventional IVF-ET in aged patients, and not impaired by a single embryo transferred. Better embryo quality, as a consequence of natural selection of oocytes, better endometrium receptivity and monthly repeatability of the procedure, can balance the relatively low chance to perform ET.

Polar body morphology and spindle imaging as predictors of oocyte quality.

It has been suggested that first polar body (PBI) morphology reflects oocyte competence. Oocytes with an intact normal-sized PBI have been described as generating better day 2 embryos, higher blastocyst yield, and increased pregnancy and implantation rates. In other studies, PBI morphology was found to be unrelated to fertilization rate, embryo quality, and blastocyst formation. In a prospective analysis, the predictive value of the PBI was investigated by comparing the development of oocytes retrieved from intracytoplasmic sperm injection patients and displaying different PBI morphology, classified according to the following characteristics: normal size and smooth surface (I), fragmented (II), rough surface (III), or large size (IV). Fertilization rates were 59, 57, 64 and 60% respectively. No significant differences were found between the various groups. The proportions of high quality (grade A) day 2 embryos were also comparable among groups I-III (14, 12 and 17% respectively), while the low number of grade A embryos in group IV (two embryos) did not allow comparison with the other classes. These data do not suggest that PBI selection can contribute to identification of embryos with high developmental ability. In order to establish alternative criteria for oocyte selection, a metaphase II (MII) spindle analysis was also conducted via Polscope. In oocytes of patients of different age, spindle retardance (which reflects the high order and density of microtubules) was compared with parameters of embryo development. In aged patients, a trend was observed between low retardance and poor embryo quality, although in general the association between retardance and oocyte developmental performance did not reach statistical significance.