152 research outputs found

    Ingestion of amniotic fluid enhances the facilitative effect of VTA morphine on the onset of maternal behavior in virgin rats

    Get PDF
    Previous research has shown that injection of morphine into the ventral tegmental area(VTA) facilitates the onset of maternal behavior in virgin female rats, and injection of the opioid antagonist naltrexone into the VTA disrupts the onset of maternal behavior in parturient rats. Placentophagia – ingestion of placenta and amniotic fluid, usually at parturition – modifies central opioid processes. Ingestion of the active substance in placenta and amniotic fluid, Placental Opioid-Enhancing Factor (POEF), enhances the hypoalgesic effect of centrally administered morphine, and more specifically, enhances δ- and κ-opioid-receptor-\ud mediated hypoalgesia and attenuates μ-opioid-receptor-mediated hypoalgesia. POEF (in placenta or amniotic fluid) ingestion does not, by itself, produce hypoalgesia. In the\ud present study, we tested the hypothesis that ingestion of amniotic fluid enhances the facilitative effect of opioid activity (unilateral morphine injection) in the VTA on the rate of onset of maternal behavior. Virgin female Long-Evans rats were given one intra-VTA injection of morphine sulfate (0.0, 0.01, or 0.03 μg, in saline) and an orogastric infusion of 0.25 ml amniotic fluid or saline once each day of the first three days of the 10-day testing\ud period. Subjects were continuously exposed to foster pups that were replaced every 12 h; replacement of pups was followed by a 15-min observation period. Maternal behavior\ud latency was determined by the first of two consecutive tests wherein the subject displayed pup retrieval, pup licking in the nest, and crouching over all foster pups, during the 15-min observation. We confirmed the previous finding that the VTA injection, alone, of 0.03 μg morphine shortened the latency to show maternal behavior and that 0.0 μg and 0.01 μg morphine did not. Ingestion of amniotic fluid (and therefore POEF) facilitated the onset of\ud maternal behavior in rats receiving an intra-VTA microinjection of an otherwise subthreshold dose of morphine (0.01 μg)

    A multiple discriminant analysis of technical indicators of the NYSE /

    Get PDF

    Merkel cell carcinoma metastasis and dermatofibrosarcoma protuberans presenting as a collision tumour: a case report and review of the literature

    Get PDF
    <p>Abstract</p> <p>Introduction</p> <p>Merkel cell carcinoma and dermatofibrosarcoma protuberans are two very rare neoplasms. The simultaneous occurrence of two different tumour entities at the same anatomical site, collision tumours, is a rare phenomenon.</p> <p>Case presentation</p> <p>We present a rare case of a 74-year-old woman with a previous history of a recurrent dermatofibrosarcoma protuberans presenting with a metastatic Merkel cell carcinoma. Further investigation revealed a collision tumour of a metastatic lesion of the Merkel cell carcinoma within a tumour relapse of a dermatofibrosarcoma protuberans.</p> <p>Conclusion</p> <p>Synchronous occurrence of two different tumour entities is extremely rare and has not been described for Merkel cell carcinoma and dermatofibrosarcoma. Merkel cell carcinoma, a tumour of the elderly or immunocompromised patients, leads to early metastasis and can be expected to be the limiting factor for prognoses.</p

    Trading and investing in volatility products

    Get PDF
    Since the banking crisis the market for volatility exchange-traded products has developed rapidly as it opens to clients beyond the large institutional investor pool. Speculation is driven by increasingly complex leveraged and inverse exposures including those that attempt to trade on significant roll costs in volatility futures curves. Longer-term investors use these products for the purposes of equity diversification, driven by fears of an ongoing Eurozone crisis. We survey the burgeoning academic literature in this area and present a comprehensive and up-to-date comparison of the market and statistical characteristics of European and US exchange-traded volatility products

    Diversification with volatility products

    Get PDF
    Recent changes to clearing-house regulations have promoted exchange-traded products offering risk premia previously accessible only over-the-counter. Thus, as correlations increase between equity, bonds and commodities, a new strand of research questions the benefits of home-grown diversification using volatility products. First we ask: “What expected returns will induce equity and bond investors to perceive ex-ante diversification benefits from adding volatility?” We call this the optimal diversification threshold. We derive the theoretical thresholds for minimum-variance, mean-variance and Black–Litterman optimization. Empirical analysis of US and European markets shows that volatility diversification is frequently perceived to be optimal, ex-ante, but these apparent benefits are almost never realized, being eroded by high roll and transaction costs. Exchange-traded volatility only proved an effective diversifier during the banking crisis. At other times long equity and bond portfolios diversified with volatility futures have not performed as well as those without diversification, or even those diversified with commodities
    corecore