299 research outputs found

    Amphibian and reptile diversity of Northern Guatemala

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    Throughout the world an ever-burgeoning human population is putting increasing pressure on natural resources. One result of that pressure is an increasing loss of natural habitat through habitat destruction and change in land use. Currently the effects of change in land use are most strongly felt in tropical regions that also hold the highest levels of biodiversity. Significant gaps in our knowledge exist regarding how changes in land use affect faunal biodiversity and abundance, especially in the case of tropical amphibians and reptiles which can be particularly sensitive to environmental change and are often difficult to detect. Surveys were conducted in Laguna del Tigre National Park (LTNP) in Northern Guatemala with the aim of 1) comparing amphibian and reptile diversity in undisturbed forest and forest adjacent to land converted to agriculture; 2) determining predictors of diversity and finer scale effects of change in land use on assemblage structure; and 3) using the presence of common widespread species to predict hotspots of diversity on a wider regional level. Ninety-two species of amphibians and reptiles were detected from 2013 to 2016 representing 26 families and 5 orders. Eighteen percent of amphibian species and 50% of reptiles were found to be of regional conservation concern, considerably higher than when those species were considered at current national and global levels. Diversity of amphibians and reptiles was significantly lower in forest adjacent to agriculture than in undisturbed habitat. Assemblage structure was significantly altered in disturbed habitat, with a few common species dominating other species that were present. Tolerance of dry environmental conditions and specialised diet were identified as traits that allowed for successful colonisation of disturbed forest. The presence of species with widespread distributions revealed more information about overall diversity of a location than did the presence of rare species. Moreover, the presence of species common to multiple locations in the Mayan Biosphere Reserve (MBR) could be used to predict levels of diversity at under-sampled locations. Change in land use and resulting disturbance of adjacent forest could have a more significant impact on amphibians and reptiles than realized. Conservation policy for amphibians and reptiles within the MBR should take their local conservation status into consideration in addition to national and global assessments

    An investigation into grazing impacts by New Forest herbivores on inclosure and open woodland patch areas

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    Several studies have researched the effects that ungulates can have on woodland ecosystems, however, limited applied research has been undertaken on the unique nature of the New Forest National Park. This research compares two small woodland parcels in the New Forest – one that herbivores are excluded from, and one that herbivores have access to. In both woodlands, data was collected on browse heights, plant species diversity, tree diameters, and light levels. Data was analysed using a multivariate Generalised Linear Models (GLM) to assess the significance of abiotic, ecological and impact factors. The results show that herbivores in the New Forest significantly impact woodland through browsing effects. The woodland that grazing herbivores had access to was shown to have significantly lower plant species diversity and abundance, demonstrating the influence of browsing effects over time. Such findings have implications for how nature reserves are managed using open and inclosure techniques across large national parks, where land is divided into parcels. Open areas may need to control for browsing depending on conservation aims. Further research to extend on this study should take into consideration seasonality

    Conservation of the Gharial (Gavialis gangeticus) at the Madras Crocodile Bank Trust, Chennai, India

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    Gavialis gangeticus are in serious decline in the wild. In this short article we provide an overview of Gharial ecology and current conservation measures taking place at the Madras Crocodile Bank Trust in India

    Prebiotic effects: metabolic and health benefits

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    The different compartments of the gastrointestinal tract are inhabited by populations of micro-organisms. By far the most important predominant populations are in the colon where a true symbiosis with the host exists that is a key for well-being and health. For such a microbiota, 'normobiosis' characterises a composition of the gut 'ecosystem' in which micro-organisms with potential health benefits predominate in number over potentially harmful ones, in contrast to 'dysbiosis', in which one or a few potentially harmful micro-organisms are dominant, thus creating a disease-prone situation. The present document has been written by a group of both academic and industry experts (in the ILSI Europe Prebiotic Expert Group and Prebiotic Task Force, respectively). It does not aim to propose a new definition of a prebiotic nor to identify which food products are classified as prebiotic but rather to validate and expand the original idea of the prebiotic concept (that can be translated in 'prebiotic effects'), defined as: 'The selective stimulation of growth and/or activity(ies) of one or a limited number of microbial genus(era)/species in the gut microbiota that confer(s) health benefits to the host.' Thanks to the methodological and fundamental research of microbiologists, immense progress has very recently been made in our understanding of the gut microbiota. A large number of human intervention studies have been performed that have demonstrated that dietary consumption of certain food products can result in statistically significant changes in the composition of the gut microbiota in line with the prebiotic concept. Thus the prebiotic effect is now a well-established scientific fact. The more data are accumulating, the more it will be recognised that such changes in the microbiota's composition, especially increase in bifidobacteria, can be regarded as a marker of intestinal health. The review is divided in chapters that cover the major areas of nutrition research where a prebiotic effect has tentatively been investigated for potential health benefits. The prebiotic effect has been shown to associate with modulation of biomarkers and activity(ies) of the immune system. Confirming the studies in adults, it has been demonstrated that, in infant nutrition, the prebiotic effect includes a significant change of gut microbiota composition, especially an increase of faecal concentrations of bifidobacteria. This concomitantly improves stool quality (pH, SCFA, frequency and consistency), reduces the risk of gastroenteritis and infections, improves general well-being and reduces the incidence of allergic symptoms such as atopic eczema. Changes in the gut microbiota composition are classically considered as one of the many factors involved in the pathogenesis of either inflammatory bowel disease or irritable bowel syndrome. The use of particular food products with a prebiotic effect has thus been tested in clinical trials with the objective to improve the clinical activity and well-being of patients with such disorders. Promising beneficial effects have been demonstrated in some preliminary studies, including changes in gut microbiota composition (especially increase in bifidobacteria concentration). Often associated with toxic load and/or miscellaneous risk factors, colon cancer is another pathology for which a possible role of gut microbiota composition has been hypothesised. Numerous experimental studies have reported reduction in incidence of tumours and cancers after feeding specific food products with a prebiotic effect. Some of these studies (including one human trial) have also reported that, in such conditions, gut microbiota composition was modified (especially due to increased concentration of bifidobacteria). Dietary intake of particular food products with a prebiotic effect has been shown, especially in adolescents, but also tentatively in postmenopausal women, to increase Ca absorption as well as bone Ca accretion and bone mineral density. Recent data, both from experimental models and from human studies, support the beneficial effects of particular food products with prebiotic properties on energy homaeostasis, satiety regulation and body weight gain. Together, with data in obese animals and patients, these studies support the hypothesis that gut microbiota composition (especially the number of bifidobacteria) may contribute to modulate metabolic processes associated with syndrome X, especially obesity and diabetes type 2. It is plausible, even though not exclusive, that these effects are linked to the microbiota-induced changes and it is feasible to conclude that their mechanisms fit into the prebiotic effect. However, the role of such changes in these health benefits remains to be definitively proven. As a result of the research activity that followed the publication of the prebiotic concept 15 years ago, it has become clear that products that cause a selective modification in the gut microbiota's composition and/or activity(ies) and thus strengthens normobiosis could either induce beneficial physiological effects in the colon and also in extra-intestinal compartments or contribute towards reducing the risk of dysbiosis and associated intestinal and systemic pathologies

    Ecology and morphology of the dwarf bromeliad boa Ungaliophis panamensis (Squamata, Boidae, Ungaliophiinae) in Costa Rica and Panama

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    Ecological and morphological data on Ungaliophis panamensis is extremely limited as this species is rarely encountered. These knowledge gaps have been advanced in this study where data was analysed from a small sample of snakes collected in two tropical forested environments in Costa Rica and Pana-ma. Standardised major axis testing and a Bayesian latent variable ordination revealed that the species is sexually dimorphic, closely associated with tree trunks in natural forested areas, and occasionally discovered in rural buildings. Although further investigation into its natural history is warranted, this study shows that even with just a few individuals it is possible to elucidate ecological information that is relevant to the conservation of snake species

    Objective burden, resources, and other stressors among informal cancer caregivers: a hidden quality issue?

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    A great deal of clinical cancer care is delivered in the home by informal caregivers (e.g. family, friends), who are often untrained. Caregivers' context varies widely, with many providing care despite low levels of resources and high levels of additional demands

    Indoor Residual Spraying in Combination with Insecticide-Treated Nets Compared to Insecticide-Treated Nets Alone for Protection against Malaria: A Cluster Randomised Trial in Tanzania.

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    Insecticide-treated nets (ITNs) and indoor residual spraying (IRS) of houses provide effective malaria transmission control. There is conflicting evidence about whether it is more beneficial to provide both interventions in combination. A cluster randomised controlled trial was conducted to investigate whether the combination provides added protection compared to ITNs alone. In northwest Tanzania, 50 clusters (village areas) were randomly allocated to ITNs only or ITNs and IRS. Dwellings in the ITN+IRS arm were sprayed with two rounds of bendiocarb in 2012. Plasmodium falciparum prevalence rate (PfPR) in children 0.5-14 y old (primary outcome) and anaemia in children <5 y old (secondary outcome) were compared between study arms using three cross-sectional household surveys in 2012. Entomological inoculation rate (secondary outcome) was compared between study arms. IRS coverage was approximately 90%. ITN use ranged from 36% to 50%. In intention-to-treat analysis, mean PfPR was 13% in the ITN+IRS arm and 26% in the ITN only arm, odds ratio = 0.43 (95% CI 0.19-0.97, n = 13,146). The strongest effect was observed in the peak transmission season, 6 mo after the first IRS. Subgroup analysis showed that ITN users were additionally protected if their houses were sprayed. Mean monthly entomological inoculation rate was non-significantly lower in the ITN+IRS arm than in the ITN only arm, rate ratio = 0.17 (95% CI 0.03-1.08). This is the first randomised trial to our knowledge that reports significant added protection from combining IRS and ITNs compared to ITNs alone. The effect is likely to be attributable to IRS providing added protection to ITN users as well as compensating for inadequate ITN use. Policy makers should consider deploying IRS in combination with ITNs to control transmission if local ITN strategies on their own are insufficiently effective. Given the uncertain generalisability of these findings, it would be prudent for malaria control programmes to evaluate the cost-effectiveness of deploying the combination.\ud \u

    Human mass balance study of the novel anticancer agent ixabepilone using accelerator mass spectrometry

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    Ixabepilone (BMS-247550) is a semi-synthetic, microtubule stabilizing epothilone B analogue which is more potent than taxanes and has displayed activity in taxane-resistant patients. The human plasma pharmacokinetics of ixabepilone have been described. However, the excretory pathways and contribution of metabolism to ixabepilone elimination have not been determined. To investigate the elimination pathways of ixabepilone we initiated a mass balance study in cancer patients. Due to autoradiolysis, ixabepilone proved to be very unstable when labeled with conventional [14C]-levels (100 μCi in a typical human radio-tracer study). This necessitated the use of much lower levels of [14C]-labeling and an ultra-sensitive detection method, Accelerator Mass Spectrometry (AMS). Eight patients with advanced cancer (3 males, 5 females; median age 54.5 y; performance status 0–2) received an intravenous dose of 70 mg, 80 nCi of [14C]ixabepilone over 3 h. Plasma, urine and faeces were collected up to 7 days after administration and total radioactivity (TRA) was determined using AMS. Ixabepilone in plasma and urine was quantitated using a validated LC-MS/MS method. Mean recovery of ixabepilone-derived radioactivity was 77.3% of dose. Fecal excretion was 52.2% and urinary excretion was 25.1%. Only a minor part of TRA is accounted for by unchanged ixabepilone in both plasma and urine, which indicates that metabolism is a major elimination mechanism for this drug. Future studies should focus on structural elucidation of ixabepilone metabolites and characterization of their activities
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