308 research outputs found

    A novel selective 11b-hydroxysteroid dehydrogenase type 1 inhibitor prevents human adipogenesis.

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    Glucocorticoid excess increases fat mass, preferentially within omental depots; yet circulating cortisol concentrations are normal in most patients with metabolic syndrome (MS). At a pre-receptor level, 11b-hydroxysteroid dehydrogenase type 1 (11b-HSD1) activates cortisol from cortisone locally within adipose tissue, and inhibition of 11b-HSD1 in liver and adipose tissue has been proposed as a novel therapy to treat MS by reducing hepatic glucose output and adiposity. Using a transformed human subcutaneous preadipocyte cell line (Chub-S7) and human primary preadipocytes, we have defined the role of glucocorticoids and 11b-HSD1 in regulating adipose tissue differentiation. Human cells were differentiated with 1.0 mM cortisol (F), or cortisone (E) with or without 100 nM of a highly selective 11b-HSD1 inhibitor PF-877423. 11b-HSD1 mRNA expression increased across adipocyte differentiation (P!0.001, nZ4), which was paralleled by an increase in 11b-HSD1 oxo-reductase activity (from nil on day 0 to 5.9G1.9 pmol/mg per h on day 16,P!0.01, nZ7). Cortisone enhanced adipocyte differentiation; fatty acid-binding protein 4 expression increased 312-fold (P!0.001) and glycerol-3-phosphate dehydrogenase 47-fold (P!0.001) versus controls. This was abolished by co-incubation with PF-877423. In addition, cellular lipid content decreased significantly. These findings were confirmed in the primary cultures of human subcutaneous preadipocytes. The increase in 11b-HSD1 mRNA expression and activity is essential for the induction of human adipogenesis. Blocking adipogenesis with a novel and specific 11b-HSD1 inhibitor may represent a novel approach to treat obesity in patients with MS

    A Critical Assessment of Protection for Key Wildlife and Salmon Habitats under the Proposed British Columbia Central Coast Land and Resource Management Plan

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    The Central Coast Land and Resource Management Plan (CCLRMP) table recently declared a consensus1 on proposed protected areas for British Columbia’s Central Coast. This region is recognized for its globally rare and largely intact mainland and island ecosystems and land use decisions should reflect this importance. We evaluated the efficacy of this proposal using a spatial assessment of habitat. We focus on protected areas in the context of the overall CCLRMP. We examined the level of protection provided by the CCLRMP in three key coastal habitats: deer winter range, wolf reproductive habitat, and salmon reproductive and rearing habitat. Assessment of deer winter range was limited to Heiltsuk Territory, which comprises a large proportion of the CCLRMP region

    The genetic legacy of extirpation and re-colonization in Vancouver Island wolves

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    Hybridization between wild and domestic species is of conservation concern because it can result in the loss of adaptations and/or disappearance of a distinct taxon. Wolves from Vancouver Island, British Columbia (Canada), have been subject to several eradication campaigns during the twentieth century and were considered virtually extirpated between 1950 and 1970. In this study, we use control region mitochondrial DNA sequences and 13 autosomal microsatellite loci to characterize Vancouver Island wolves as well as dogs from British Columbia. We observe a turnover in the haplotypes of wolves sampled before and after the 1950-1970 period, when there was no permanent wolf population on the island, supporting the probable local extinction of wolves on Vancouver Island during this time, followed by re-colonization of the island by wolves from mainland British Columbia. In addition, we report the presence of a domestic dog mtDNA haplotype in three individuals eliminated in 1986 that were morphologically identified as wolves. Here we show that Vancouver Island wolves were also identified as wolves based on autosomal microsatellite data. We attribute the hybridization event to the episodically small size of this population during the re-colonization event. Our results demonstrate that at least one female hybrid offspring, resulting from a cross of a male wolf and a female dog or a female hybrid pet with dog mtDNA, successfully introgressed into the wolf population. No dog mtDNA has been previously reported in a population of wild wolves. Genetic data show that Vancouver Island wolves are distinct from dogs and thus should be recognized as a population of wild wolves. We suggest that the introgression took place due to the Allee effect, specifically a lack of mates when population size was low. Our findings exemplify how small populations are at risk of hybridization. © 2009 Springer Science+Business Media B.V.Peer Reviewe

    Early Ontogenetic Diet in Gray Wolves, Canis lupus, of Coastal British Columbia

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    Within populations, different age classes often consume dissimilar resources, and provisioning of juveniles by adults is one mechanism by which this can occur. Although the diet of Gray Wolves (Canis lupus) has been studied extensively, the diet of pups is largely unknown. We examined faeces deposited by altricial pups and adult providers during the first two months following birth at two den sites over two years on the central coast of British Columbia, Canada. Pups and adult wolves consumed similar species, and Black-tailed Deer (Odocoileus hemionus) constituted most of the diet for both age groups. Pup and adult diet, however, diverged. Specifically, adult deer occurred significantly less frequently in the diet of pups than in the diet of adult wolves, which suggests that adults selectively provisioned pups. We speculate that this may relate to adaptive strategies of adult wolves to provide their offspring with food of optimal nutritional value or reduced parasitic burden, and/or logistic factors associated with provisioning such as prey transportability and availability

    Early Ontogenetic Diet in Gray Wolves, Canis lupus, of Coastal British Columbia

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    Within populations, different age classes often consume dissimilar resources, and provisioning of juveniles by adults is one mechanism by which this can occur. Although the diet of Gray Wolves (Canis lupus) has been studied extensively, the diet of pups is largely unknown. We examined faeces deposited by altricial pups and adult providers during the first two months following birth at two den sites over two years on the central coast of British Columbia, Canada. Pups and adult wolves consumed similar species, and Black-tailed Deer (Odocoileus hemionus) constituted most of the diet for both age groups. Pup and adult diet, however, diverged. Specifically, adult deer occurred significantly less frequently in the diet of pups than in the diet of adult wolves, which suggests that adults selectively provisioned pups. We speculate that this may relate to adaptive strategies of adult wolves to provide their offspring with food of optimal nutritional value or reduced parasitic burden, and/or logistic factors associated with provisioning such as prey transportability and availability

    Facts from Faeces: Prey Remains in Wolf, Canis lupus, Faeces Revise Occurrence Records for Mammals of British Columbia's Coastal Archipelago

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    Archipelagos often harbour taxa that are endemic and vulnerable to disturbance. Conservation planning and research for these areas depend fundamentally on accurate and current taxonomic inventories. Although basic ecological information is in its infancy, the temperate rainforest islands of coastal British Columbia are undergoing rapid human-caused modification, particularly logging. We report herein new mammal records for these islands as determined by prey remains in the faeces of Wolves (Canis lupus), the area’s apex mammalian terrestrial predator. Of particular interest is our detection of Marten (Martes americana) on islands previously inventoried and island occupancy by Moose (Alces alces), which have apparently migrated recently to coastal British Columbia. Remains in faeces provided valuable new species occurrence information, but more extensive and focused inventories are required to generate predictions of island occupancy by mammals based on biotic and abiotic landscape features

    Maintaining Ethical Standards during Conservation Crises

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    Many species at risk in Canada and globally are at or approaching a crisis, especially where little or nothing consequential is being done to prevent extirpation. Such is the case of endangered boreal caribou (Rangifer tarandus caribou) in southern Alberta, Canada. Expedient but inadequate emergency ‘fixes’ have been experimentally implemented to arrest their decline and potential extirpation, but use of these measures raises important ethical problems. In their study of the effects of killing wolves (Canis lupus) on the Little Smoky woodland caribou population, Hervieux et al. (2014a) employed lethal methods that included shooting a firearm from a helicopter and the use of strychnine baits. Both of these methods raise critical questions with regard to animal welfare. When it is necessary to kill an animal, reliable humane procedures must be used to avoid pain or distress, and produce rapid loss of consciousness until death occurs. Also relevant are formal approvals by government and institutional animal ethics committees that adhere to Canadian Council on Animal Care (CCAC) guidelines. Shooting a moving animal from a helicopter is prone to error and not conducive to shots that quickly render animals insensitive to pain or produce a consistently quick kill. Strychnine does not meet the CCAC’s criteria for an acceptable killing method, and is specifically prohibited as an injectable option for euthanizing animals. Its use under uncontrolled conditions at bait sites is likely even less suitable. In addition, the risks of non-lethal and painful injuries from this poison and associated deaths to large numbers of non-target animals clearly contravene the CCAC guidelines for wildlife research. This study did not meet the CCAC’s guidelines and did not adhere to the Canadian Journal of Zoology’s requirement that all research must be approved by an institutional animal care committee. More broadly, and regardless of the failure of formal safeguards and implicit justifications offered by authors, we should be concerned when researchers impose suffering on wild animals and advocate for such programs to continue. Based on an apparent lack of compliance with CCAC’s guidelines, we believe that this controversial study should never have taken place and should not have been published by the Canadian Journal of Zoology. Experiments that involve the intentional inhumane killing of animals violate the fundamental principles of ethical science and rightfully endanger the reputation of science and scientists, as well as the journals willing to publish them. We recommend that CCAC guidelines be further developed to clearly address field methods used in wildlife studies, namely the shooting of animals from a helicopter, and the use of strychnine in baits. Also, independent audits should be conducted to investigate individual researchers and their studies, and the journals that publish this work, to ensure that CCAC guidelines are properly followed, even by researchers who collaborate well after the animal-based procedures have been carried out
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