992 resultados para Large Mammals


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Evidence has emerged that the initiation and growth of gliomas is sustained by a subpopulation of cancer-initiating cells (CICs). Because of the difficulty of using markers to tag CICs in gliomas, we have previously exploited more robust phenotypic characteristics, including a specific morphology and intrincic autofluorescence, to identify and isolate a subpopulation of glioma CICs, called FL1(+). The objective of this study was to further validate our method in a large cohort of human glioma and a mouse model of glioma. Seventy-four human gliomas of all grades and the GFAP-V(12)HA-ras B8 mouse model were analyzed for in vitro self-renewal capacity and their content of FL1(+). Nonneoplastic brain tissue and embryonic mouse brain were used as control. Genetic traceability along passages was assessed with microsatellite analysis. We found that FL1(+) cells from low-grade gliomas and from control nonneoplasic brain tissue show a lower level of autofluorescence and undergo a restricted number of cell divisions before dying in culture. In contrast, we found that FL1(+) cells derived from many but not all high-grade gliomas acquire high levels of autofluorescence and can be propagated in long-term cultures. Moreover, FL1(+) cells show a remarkable traceability over time in vitro and in vivo. Our results show that FL1(+) cells can be found in all specimens of a large cohort of human gliomas of different grades and in a model of genetically induced mouse glioma as well as nonneoplastic brain. However, their self-renewal capacity is variable and seems to be dependent on the tumor grade.

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Large or giant cellular blue nevi are usually congenital and represent a challenge for the physician. Close anatomic structures may be altered by the size of the moles. In this article, we report the case of an uncommon large, agminated, cellular blue nevus of the 'plaque type' in a 42-year-old female. Due to the risks of malignant melanoma development on a large or giant blue nevus, we highlight the importance of proper histopathological diagnosis. Furthermore, because of the possibility that the nevus may invade the bone and cerebral tissues, we discuss the indication of a radiological diagnosis. The accurate correlation to clinical and histopathological findings and appropriate multidisciplinary management can save the lives of patients. © 2013 S. Karger AG, Basel.

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Posterior chest wall defects are frequently encountered after excision of tumors as a result of trauma or in the setting of wound dehiscence after spine surgery. Various pedicled fasciocutaneous and musculocutaneous flaps have been described for the coverage of these wounds. The advent of perforator flaps has allowed the preservation of muscle function but their bulk is limited. Musculocutaneous flaps remain widely employed. The trapezius and the latissimus dorsi (LD) flaps have been used extensively for upper and middle posterior chest wounds, respectively. Their bulk allows for obliteration of the dead space in deep wounds. The average width of the LD skin paddle is limited to 10-12 cm if closure of the donor site is expected without skin grafting. In 2001 a modification of the skin paddle design was introduced in order to allow large flaps to be raised without requiring grafts or flaps for donor site closure. This V-Y pattern allows coverage of large anterior chest defects after mastectomy. We have modified this flap to allow its use for posterior chest wall defects. We describe the flap design, its indications, and its limitations with three clinical cases. Level of Evidence V This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors at www.springer.com/00266 .

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Full-field X-ray microscopy is a valuable tool for 3D observation of biological systems. In the soft X-ray domain organelles can be visualized in individual cells while hard X-ray microscopes excel in imaging of larger complex biological tissue. The field of view of these instruments is typically 10(3) times the spatial resolution. We exploit the assets of the hard X-ray sub-micrometer imaging and extend the standard approach by widening the effective field of view to match the size of the sample. We show that global tomography of biological systems exceeding several times the field of view is feasible also at the nanoscale with moderate radiation dose. We address the performance issues and limitations of the TOMCAT full-field microscope and more generally for Zernike phase contrast imaging. Two biologically relevant systems were investigated. The first being the largest known bacteria (Thiomargarita namibiensis), the second is a small myriapod species (Pauropoda sp.). Both examples illustrate the capacity of the unique, structured condenser based broad-band full-field microscope to access the 3D structural details of biological systems at the nanoscale while avoiding complicated sample preparation, or even keeping the sample environment close to the natural state.

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SummaryGene duplication and neofunctidnalization are important processes in the evolution of phenotypic complexity. They account for important evolutionary novelties that confer ecological adaptation, such as the major histocompatibility complex (MHC), a multigene family with a central role in vertebrates' adaptive immune system. Multigene families, which evolved in large part through duplication, represent promising systems to study the still strongly depbated relative roles of neutral and adaptive processes in the evolution of phenotypic complexity. Detailed knowledge on ecological function and a well-characterized evolutionary history place the mammals' MHC amongst ideal study systems. However mammalian MHCs usually encompass several million base pairs and hold a large number of functional and non-functional duplicate genes, which makes their study complex. Avian MHCs on the other hand are usually way more compact, but the reconstruction of. their evolutionary history has proven notoriously difficult. However, no focused attempt has been undertaken so far to study the avian MHC evolutionary history in a broad phylogenetic context and using adequate gene regions.In the present PhD, we were able to make important contributions to the understanding of the long-term evolution of the avian MHC class II Β (MHCI1B). First, we isolated and characterized MHCIIB genes in barn owl (Tyto alba?, Strigiformes, Tytonidae), a species from an avian lineage in which MHC has not been studied so far. Our results revealed that with only two functional MHCIIB genes the MHC organization of barn owl may be similar to the 'minimal essential' MHC of chicken (Gallus gallus), indicating that simple MHC organization may be ancestral to birds. Taking advantage of the sequence information from barn owl, we studied the evolution of MHCIIB genes in 13 additional species of 'typical' owls (Strigiformes, Strigidae). Phylogenetic analyses revealed that according to their function, in owls the peptide-binding region (PBR) encoding exon 2 and the non-PBR encoding exon 3 evolve by different patterns. Exon 2 exhibited an evolutionary history of positive selection and recombination, while exon 3 traced duplication history and revealed two paralogs evolving divergently from each other in owls, and in a shorebird, the great snipe {Gallinago media). The results from exon 3 were the first ever from birds to demonstrate gene orthology in species that diverged tens of millions of years ago, and strongly questioned whether the taxa studied before provided an adequate picture of avian MHC evolution. In a follow-up study, we aimed at explaining a striking pattern revealed by phylogenetic trees analyzing the owl sequences along with MHCIIB sequences from other birds: One owl paralog (termed DAB1) grouped with sequences of passerines and falcons, while the other (DAB2) grouped with wildfowl, penguins and birds of prey. This could be explained by either a duplication event preceding the evolution of these bird orders, or by convergent evolution of similar sequences in a number of orders. With extensive phylogenetic analyses we were able to show, that indeed a duplication event preceeded the major avian radiation -100 my ago, and that following this duplication, the paralogs evolved under positive selection. Furthermore, we showed that the divergently evolving amino acid residues in the MHCIIB-encoded β-chain potentially interact with the MHCI I α-chain, and that molecular coevolution of the interacting residues may have been involved in the divergent evolution of the MHCIIB paralogs.The findings of this PhD are of particular interest to the understanding of the evolutionary history of the avian MHC and, by providing essential information on long-term gene history in the avian MHC, open promising perspectives for advances in the understanding of the evolution of multigene families in general, and for avian MHC organization in particular. Amongst others I discuss the importance of including protein structure in the phylogenetic study of multigene families, and the roles of ecological versus molecular selection pressures. I conclude by providing a population genomic perspective on avian MHC, which may serve as a basis for future research to investigate the relative roles of neutral processes involving effective population size effects and of adaptation in the evolution of avian MHC diversity and organization.RésuméLa duplication de gènes et leur néo-fonctionnalisation sont des processus importants dans l'évolution de la complexité phénotypique. Ils sont impliqués dans l'apparition d'importantes nouveautés évolutives favorisant l'adaptation écologique, comme c'est le cas pour le complexe majeur d'histocompatibilité large contexte phylogénétique et en utilisant des régions géniques adéquates.Ce travail de thèse a contribué à la compréhension de l'évolution à long-terme du CMH aviaire classe II Β (CMH II Β). Nous avons isolé et caractérisé les gènes CMH I IB de la chouette effraie (Tyto alba; Strigiformes, Tytonidae), une espèce appartenant à une lignée aviaire dont le CMH n'avait pas été étudié jusqu'ici. Avec uniquement deux gènes CMHIIB fonctionnels, l'organisation CMH de la chouette effraie semble être comparable à celle "minimale" du poulet (Gallus gallus), ce qui suggère qu'une organisation simple du CMH pourrait être ancestrale chez les oiseaux. En se basant sur l'information obtenue pour cette espèce, nous avons ensuite étudié l'évolution des gènes CMHIIB chez 13 espèces de chouettes "typiques" (Strigiformes, Strigidae). Les analyses phylogénétiques ont révélé que chez les chouettes, selon leur fonction, l'exon 2 codant pour la 'peptide-binding region' (PBR) et l'exon 3 ne codant pas pour la région PBR évoluent de manière distincte. L'exon 2 montre une histoire évolutive de sélection positive et recombinaison, tandis que l'exon 3 retrace l'histoire de duplication et révèle deux paralogues évoluant de façon divergente chez les chouettes, ainsi que chez un limicole, la bécassine double (Gallinago media). Les résultats découlant de l'analyse de l'exon 3 ont montré pour la première fois chez les oiseaux une orthologie de gènes chez des espèces ayant divergé il y a des dizaines de millions d'années. Dans une deuxième étude, nous avons voulu expliquer le pattern surprenant révélé par les arbres phylogénétiques lorsque les séquences CMHIIB des chouettes sont analysées avec les séquences d'autres oiseaux: un paralogue de chouette (appelé DABI) forme un groupe avec les séquences de passereaux et faucons, tandis que l'autre (DAB2) se regroupe avec les gallo-ansériformes, les manchots et les rapaces diurnes. Ceci pourrait être expliqué soit par une duplication qui a précédé l'évolution de ces ordres aviaires soit par évolution convergente dans un certain nombre d'ordres. Grâce à des analyses phylogénétiques approfondies, nous avons pu montrer qu'un événement de duplication a effectivement précédé la radiation aviaire principale d'il y a environ 100 millions d'années, et qu'après cette duplication les paralogues ont évolué sous sélection positive. De plus, les résidus d'acides aminés évoluant de façon divergente dans la chaîne β codée par le CMHIIB interagissent potentiellement avec la chaîne α codée par le CMHII, et que la coévolution moléculaire de ces résidus pourrait être à la base de l'évolution divergente des paralogues CMHIIB.Dans cette thèse sont discutés entre autres l'importance d'inclure la structure des protéines dans l'étude phylogénétique des familles multigéniques, ainsi que les rôles respectifs des pressions sélectives écologique et moléculaire. La conclusion comporte une perspective sur la génomique des populations du CMH aviaire, qui pourrait servir de base pour de futures recherches sur les rôles relatifs joués par Îes processus neutres comprenant les effets de la taille efficace des populations et l'adaptation dans l'évolution de la diversité et l'organisation du MHC aviaire.

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The persistence of the biocontrol agent Pseudomonas fluorescens CHA0 in the surface horizon of 12 large outdoor lysimeters planted with winter wheat, Phacelia tanacetifolia followed by spring wheat, or maize was monitored for 1 year. Soil was inoculated with a spontaneous rifampin-resistant mutant (CHA0-Rif) of CHA0, and the strain was studied by using colony counts, Kogure's direct viable counts, and total counts (immunofluorescence). The number of culturable cells of the inoculant decreased progressively from 8 to 2 log CFU/g of soil or lower. However, culturable cells of CHA0-Rif accounted for less than 1% of the total cells of the inoculant 8 months after release in autumn. Since viable but nonculturable cells represented less than a quarter of the latter, most cells of CHA0-Rif in soil were thus inactive-dormant or dead at that time. Nonculturable cells of the inoculant were predominant also in the surface horizon of the lysimeters inoculated in the spring, and a significant fraction of them were viable. Results suggest that the occurrence of nonculturable cells of CHA0-Rif was influenced by climatic factors (water availability and soil temperature) and the abundance of roots in soil. The fact that the inoculant persisted as mixed populations of cells of different physiological states, in which nonculturable cells were predominant, needs to be taken into account when assessing the autecology of wild-type or genetically modified pseudomonads released into the soil ecosystem.

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Current levels of endangerment and historical trends of species and habitats are the main criteria used to direct conservation efforts globally. Estimates of future declines, which might indicate different priorities than past declines, have been limited by the lack of appropriate data and models. Given that much of conservation is about anticipating and responding to future threats, our inability to look forward at a global scale has been a major constraint on effective action. Here, we assess the geography and extent of projected future changes in suitable habitat for terrestrial mammals within their present ranges. We used a global earth-system model, IMAGE, coupled with fine-scale habitat suitability models and parametrized according to four global scenarios of human development. We identified the most affected countries by 2050 for each scenario, assuming that no additional conservation actions other than those described in the scenarios take place. We found that, with some exceptions, most of the countries with the largest predicted losses of suitable habitat for mammals are in Africa and the Americas. African and North American countries were also predicted to host the most species with large proportional global declines. Most of the countries we identified as future hotspots of terrestrial mammal loss have little or no overlap with the present global conservation priorities, thus confirming the need for forward-looking analyses in conservation priority setting. The expected growth in human populations and consumption in hotspots of future mammal loss mean that local conservation actions such as protected areas might not be sufficient to mitigate losses. Other policies, directed towards the root causes of biodiversity loss, are required, both in Africa and other parts of the world.

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There are different approaches to dealing with alcohol related problems in the workplace. A literature review indicates that two of the models that underpin programmes to deal with alcohol related problems in the workplace are the disease model and the health promotion model. The disease model considers alcoholism as an illness and uses curative techniques to restore the individual to sobriety. The health promotion model looks at the determinants of health and promotes changes in the environment and structures, which would support healthy behaviour in relation to alcohol. Employee Assistance Programmes (EAPs) may have elements of both theses models. Dealing with alcohol problems at work involves a captive audience and the workplace as a setting can be used to influence healthier lifestyles. A workplace alcohol policy is a mechanism through which alcohol related issues might be dealt with, and the necessary resources and commitment of managers and staff channelled to this end. The policy aims should be clear and unambiguous, and specific plans put in place for implementing all aspects of the policy. In the case of the alcohol policy in the organisation under study, the policy was underpinned by a health promotion ethos and the policy document reflects broad aims and objectives to support this. The steering group that oversaw the development of the policy had particular needs of their own which they brought to the development process. The common theme in their needs was how to identify and support employees with alcohol related problems within an equitable staff welfare system. The role of the supervisor was recognised as crucial and training was provided to introduce the skills needed for an early intervention and constructive confrontation with employees who had alcohol related problems. Opportunities provided by this policy initiative to deal with broader issues around alcohol and to consider the determinants of health in relation to alcohol were not fully utilised. The policy formalised the procedures for dealing with people who have alcohol related problems in an equitable and supportive manner. The wider aspect of the health promotion approach does not appear to have been a priority in the development and implementation of the policy.This resource was contributed by The National Documentation Centre on Drug Use.

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The direction, intensity and shape of viability-, sexual- and fecundity selection on body mass were investigated in a natural population of the greater white-toothed shrew (Crocidura russula), combining parentage assignment through molecular techniques and mark-recapture data over several generations. A highly significant stabilizing viability selection was found in both sexes, presumably stemming from the constraints imposed by their insectivorous habits and high metabolic costs. Sexual selection, directional in both sexes, was twice as large in males than in females. Our results suggest that body mass matters in this context by facilitating the acquisition and defense of a breeding territory. No fecundity selection could be detected. The direction of sexual size dimorphism (SSD) was in agreement with the observed pattern of selective pressures: males were heavier than females, because of stronger sexual selection. SSD intensity, however, was low compared with other mammals, because of the low level of polygyny, the active role of females in territory defense and the intensity of stabilizing viability selection.

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OBJECTIVE: To evaluate the initiation of and response to tumor necrosis factor (TNF) inhibitors for axial spondyloarthritis (axSpA) in private rheumatology practices versus academic centers. METHODS: We compared newly initiated TNF inhibition for axSpA in 363 patients enrolled in private practices with 100 patients recruited in 6 university hospitals within the Swiss Clinical Quality Management (SCQM) cohort. RESULTS: All patients had been treated with ≥ 1 nonsteroidal antiinflammatory drug and > 70% of patients had a baseline Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) ≥ 4 before anti-TNF agent initiation. The proportion of patients with nonradiographic axSpA (nr-axSpA) treated with TNF inhibitors was higher in hospitals versus private practices (30.4% vs 18.7%, p = 0.02). The burden of disease as assessed by patient-reported outcomes at baseline was slightly higher in the hospital setting. Mean levels (± SD) of the Ankylosing Spondylitis Disease Activity Score were, however, virtually identical in private practices and academic centers (3.4 ± 1.0 vs 3.4 ± 0.9, p = 0.68). An Assessment of SpondyloArthritis international Society (ASAS40) response at 1 year was reached for ankylosing spondylitis in 51.7% in private practices and 52.9% in university hospitals (p = 1.0) and for nr-axSpA in 27.5% versus 25.0%, respectively (p = 1.0). CONCLUSION: With the exception of a lower proportion of patients with nr-axSpA newly treated with anti-TNF agents in private practices in comparison to academic centers, adherence to ASAS treatment recommendations for TNF inhibition was equally high, and similar response rates to TNF blockers were achieved in both clinical settings.