43 research outputs found

    Mitochondrial phylogeography and demographic history of the Vicuña: implications for conservation

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    The vicuña (Vicugna vicugna; Miller, 1924) is a conservation success story, having recovered from near extinction in the 1960s to current population levels estimated at 275 000. However, lack of information about its demographic history and genetic diversity has limited both our understanding of its recovery and the development of science-based conservation measures. To examine the evolution and recent demographic history of the vicuña across its current range and to assess its genetic variation and population structure, we sequenced mitochondrial DNA from the control region (CR) for 261 individuals from 29 populations across Peru, Chile and Argentina. Our results suggest that populations currently designated as Vicugna vicugna vicugna and Vicugna vicugna mensalis comprise separate mitochondrial lineages. The current population distribution appears to be the result of a recent demographic expansion associated with the last major glacial event of the Pleistocene in the northern (18 to 22°S) dry Andes 14–12 000 years ago and the establishment of an extremely arid belt known as the 'Dry Diagonal' to 29°S. Within the Dry Diagonal, small populations of V. v. vicugna appear to have survived showing the genetic signature of demographic isolation, whereas to the north V. v. mensalis populations underwent a rapid demographic expansion before recent anthropogenic impacts

    Stress-Induced Reinstatement of Drug Seeking: 20 Years of Progress

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    In human addicts, drug relapse and craving are often provoked by stress. Since 1995, this clinical scenario has been studied using a rat model of stress-induced reinstatement of drug seeking. Here, we first discuss the generality of stress-induced reinstatement to different drugs of abuse, different stressors, and different behavioral procedures. We also discuss neuropharmacological mechanisms, and brain areas and circuits controlling stress-induced reinstatement of drug seeking. We conclude by discussing results from translational human laboratory studies and clinical trials that were inspired by results from rat studies on stress-induced reinstatement. Our main conclusions are (1) The phenomenon of stress-induced reinstatement, first shown with an intermittent footshock stressor in rats trained to self-administer heroin, generalizes to other abused drugs, including cocaine, methamphetamine, nicotine, and alcohol, and is also observed in the conditioned place preference model in rats and mice. This phenomenon, however, is stressor specific and not all stressors induce reinstatement of drug seeking. (2) Neuropharmacological studies indicate the involvement of corticotropin-releasing factor (CRF), noradrenaline, dopamine, glutamate, kappa/dynorphin, and several other peptide and neurotransmitter systems in stress-induced reinstatement. Neuropharmacology and circuitry studies indicate the involvement of CRF and noradrenaline transmission in bed nucleus of stria terminalis and central amygdala, and dopamine, CRF, kappa/dynorphin, and glutamate transmission in other components of the mesocorticolimbic dopamine system (ventral tegmental area, medial prefrontal cortex, orbitofrontal cortex, and nucleus accumbens). (3) Translational human laboratory studies and a recent clinical trial study show the efficacy of alpha-2 adrenoceptor agonists in decreasing stress-induced drug craving and stress-induced initial heroin lapse

    No Weight for “Due Weight”? A Children’s Autonomy Principle in Best Interest Proceedings

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    Article 12 of the un Convention on the Rights of the Child (crc) stipulates that children should have their views accorded due weight in accordance with age and maturity, including in proceedings affecting them. Yet there is no accepted understanding as to how to weigh children’s views, and it is associated strongly with the indeterminate notion of “competence”. In this article, case law and empirical research is drawn upon to argue that the concept of weighing their views has been an obstacle to children’s rights, preventing influence on outcomes for children in proceedings in which their best interests are determined. Younger children and those whose wishes incline against the prevailing orthodoxy (they may resist contact with a parent, for example) particularly lose out. Children’s views appear only to be given “significant weight” if the judge agrees with them anyway. As it is the notion of autonomy which is prioritised in areas such as medical and disability law and parents’ rights, it is proposed in this article that a children’s autonomy principle is adopted in proceedings – in legal decisions in which the best interest of the child is the primary consideration, children should get to choose, if they wish, how they are involved and the outcome, unless it is likely that significant harm will arise from their wishes. They should also have “autonomy support” to assist them in proceedings. This would likely ensure greater influence for children and require more transparent decision-making by adults.</jats:p

    Gene-rich UV sex chromosomes harbor conserved regulators of sexual development

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    Nonrecombining sex chromosomes, like the mammalian Y, often lose genes and accumulate transposable elements, a process termed degeneration. The correlation between suppressed recombination and degeneration is clear in animal XY systems, but the absence of recombination is confounded with other asymmetries between the X and Y. In contrast, UV sex chromosomes, like those found in bryophytes, experience symmetrical population genetic conditions. Here, we generate nearly gapless female and male chromosome-scale reference genomes of the moss Ceratodon purpureus to test for degeneration in the bryophyte UV sex chromosomes. We show that the moss sex chromosomes evolved over 300 million years ago and expanded via two chromosomal fusions. Although the sex chromosomes exhibit weaker purifying selection than autosomes, we find that suppressed recombination alone is insufficient to drive degeneration. Instead, the U and V sex chromosomes harbor thousands of broadly expressed genes, including numerous key regulators of sexual development across land plants

    American palm ethnomedicine: A meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>Many recent papers have documented the phytochemical and pharmacological bases for the use of palms (<it>Arecaceae</it>) in ethnomedicine. Early publications were based almost entirely on interviews that solicited local knowledge. More recently, ethnobotanically guided searches for new medicinal plants have proven more successful than random sampling for identifying plants that contain biodynamic ingredients. However, limited laboratory time and the high cost of clinical trials make it difficult to test all potential medicinal plants in the search for new drug candidates. The purpose of this study was to summarize and analyze previous studies on the medicinal uses of American palms in order to narrow down the search for new palm-derived medicines.</p> <p>Methods</p> <p>Relevant literature was surveyed and data was extracted and organized into medicinal use categories. We focused on more recent literature than that considered in a review published 25 years ago. We included phytochemical and pharmacological research that explored the importance of American palms in ethnomedicine.</p> <p>Results</p> <p>Of 730 species of American palms, we found evidence that 106 species had known medicinal uses, ranging from treatments for diabetes and leishmaniasis to prostatic hyperplasia. Thus, the number of American palm species with known uses had increased from 48 to 106 over the last quarter of a century. Furthermore, the pharmacological bases for many of the effects are now understood.</p> <p>Conclusions</p> <p>Palms are important in American ethnomedicine. Some, like <it>Serenoa repens </it>and <it>Roystonea regia</it>, are the sources of drugs that have been approved for medicinal uses. In contrast, recent ethnopharmacological studies suggested that many of the reported uses of several other palms do not appear to have a strong physiological basis. This study has provided a useful assessment of the ethnobotanical and pharmacological data available on palms.</p

    Second hand smoke exposure and the risk of invasive meningococcal disease in children: systematic review and meta-analysis

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    Background Invasive meningococcal disease remains an important cause of serious morbidity and mortality in children and young people. There is a growing body of literature to suggest that exposure to passive smoke may play a role in the development of the disease, therefore we have performed a systematic review to provide a comprehensive estimate of the magnitude of this effect for smoking by any household member, by individual family members, and of maternal smoking before and after birth. Methods Four databases (Medline, Embase, PsychINFO and CAB Abstracts database) were searched to identify studies (to June 2012) and reference lists scanned for further studies. Titles, abstracts and full texts were checked for eligibility independently by two authors. Quality of included studies was assessed using the Newcastle-Ottawa Scale. Pooled odds ratios (OR) with 95% confidence intervals (CI) were estimated using random effect models, with heterogeneity quantified using I2. Results We identified 18 studies which assessed the effects of SHS on the risk of invasive meningococcal disease in children. SHS in the home doubled the risk of invasive meningococcal disease (OR 2.18, 95% CI 1.63 to 2.92, I2 = 72%), with some evidence of an exposure-response gradient. The strongest effect was seen in children under 5 years (OR 2.48, 95% CI 1.51 to 4.09, I2 = 47%). Maternal smoking significantly increased the risk of invasive meningococcal disease by 3 times during pregnancy (OR 2.93, 95% CI 1.52-5.66) and by 2 times after birth (OR 2.26, 95% CI 1.54-3.31). Conclusions SHS exposure, and particularly passive foetal exposure to maternal smoking during pregnancy, significantly increases the risk of childhood invasive meningococcal disease. It is likely that an extra 630 cases of invasive meningococcal disease annually in children under 16 are directly attributable to SHS exposure in UK homes
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