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Selected AbstractsRecent Insights into the Mechanism of Magnesium Corrosion and Research Suggestions,ADVANCED ENGINEERING MATERIALS, Issue 3 2007G. Song The opportunity to give an invited presentation to the Gordon Research Conference , Aqueous Corrosion in 2006 and reflections on the discussion at the conference were used to review our understanding of Mg corrosion mechanism, to generate new insights, to identify gaps in our knowledge and to identify research opportunities. [source] Recent Insights into Carotid Baroreflex Function in Humans Using the Variable Pressure Neck ChamberEXPERIMENTAL PHYSIOLOGY, Issue 6 2003Paul J. Fadel The variable pressure neck chamber has provided an invaluable research tool for the non-invasive assessment of carotid baroreflex (CBR) function in human investigations. The ability to construct complete stimulus-response curves and define specific parameters of the reflex function curve permits statistical comparisons of baroreflex function between different experimental conditions, such as rest and exercise. Results have convincingly indicated that the CBR stimulus-response curve is reset during exercise in an intensity-dependent manner to functionally operate around the prevailing pressure elicited by the exercise workload. Furthermore, both at rest and during exercise, alterations in stroke volume do not contribute importantly to the maintenance of arterial blood pressure by the carotid baroreceptors, and therefore, any reflex-induced changes in cardiac output (Q) are the result of CBR-mediated changes in heart rate. However, more importantly, the CBR-induced changes in mean arterial pressure (MAP) are primarily mediated by alterations in vascular conductance with only minimal contributions from Q to the initial reflex MAP response. Thus, the capacity of the CBR to regulate blood pressure depends critically on its ability to alter vascular tone both at rest and during exercise. This review will emphasize the utility of the variable pressure neck chamber to assess CBR function in human experimental investigations and the mechanisms by which the CBR responds to alterations in arterial blood pressure both at rest and during exercise. [source] Recent Insights into PDGF-Induced GliomagenesisBRAIN PATHOLOGY, Issue 3 2010Filippo Calzolari Abstract Gliomas are aggressive and almost incurable glial brain tumors which frequently display abnormal platelet-derived growth factor (PDGF) signaling. Evidence gained from studies on several in vivo animal models has firmly established a causal connection between aberrant PDGF signaling and the formation of some gliomas. However, only recently has significant knowledge been gained regarding crucial issues such as the glioma cell of origin and the relationship between the transforming stimulus and the cellular characteristics of the resulting tumor. Based on recent evidence, we propose that PDGF can bias cell-fate decisions, driving the acquisition of cell type-specific features by the progeny of multipotent neural progenitors, thus determining the shape and direction of the transformation path. Furthermore, recent data about the cellular mechanisms of PDGF-driven glioma progression and maintenance indicate that PDGF may be required, unexpectedly, to override cell contact inhibition and promote glioma cell infiltration rather than to stimulate cell proliferation. [source] Insulin resistance and fuel homeostasis: the role of AMP-activated protein kinaseACTA PHYSIOLOGICA, Issue 1 2009B. D. Hegarty Abstract The worldwide prevalence of type 2 diabetes (T2D) and related disorders of the metabolic syndrome (MS) has reached epidemic proportions. Insulin resistance (IR) is a major perturbation that characterizes these disorders. Extra-adipose accumulation of lipid, particularly within the liver and skeletal muscle, is closely linked with the development of IR. The AMP-activated protein kinase (AMPK) pathway plays an important role in the regulation of both lipid and glucose metabolism. Through its effects to increase fatty acid oxidation and inhibit lipogenesis, AMPK activity in the liver and skeletal muscle could be expected to ameliorate lipid accumulation and associated IR in these tissues. In addition, AMPK promotes glucose uptake into skeletal muscle and suppresses glucose output from the liver via insulin-independent mechanisms. These characteristics make AMPK a highly attractive target for the development of strategies to curb the prevalence and costs of T2D. Recent insights into the regulation of AMPK and mechanisms by which it modulates fuel metabolism in liver and skeletal muscle are discussed here. In addition, we consider the arguments for and against the hypothesis that dysfunctional AMPK contributes to IR. Finally we review studies which assess AMPK as an appropriate target for the prevention and treatment of T2D and MS. [source] A peek inside the neurosecretory brain through Orthopedia lensesDEVELOPMENTAL DYNAMICS, Issue 9 2008Luca Del Giacco Abstract The wealth of expression and functional data presented in this overview discloses the homeogene Orthopedia (Otp) as critical for the development of the hypothalamic neuroendocrine system of vertebrates. Specifically, the results depict the up-to-date portrait of the regulation and functions of Otp. The development of neuroendocrine nuclei relies on Otp from fish to mammals, as demonstrated for several peptide and hormone releasing neurons. Additionally, the activity of Otp is essential for the induction of the dopaminergic phenotype in the hypothalamus of vertebrates. Recent insights into the pathways required for Otp regulation have revealed the implication of the main extracellular signals acting during hypothalamic development. Alterations in these pathways are involved in several neuronal disorders, and the resultant downstream misregulation of Otp might impair the development of the hypothalamus, and be therefore responsible for the neuroendocrine dysfunctions that typify these diseases. Developmental Dynamics 237:2295,2303, 2008. © 2008 Wiley-Liss, Inc. [source] Recent insights into pre- and postnatal pyridoxal phosphate deficiency, a treatable metabolic encephalopathyDEVELOPMENTAL MEDICINE & CHILD NEUROLOGY, Issue 7 2010PETER BAXTER Editor in Chief No abstract is available for this article. [source] Recent insights into the signals that control ,,/,,-lineage fateIMMUNOLOGICAL REVIEWS, Issue 1 2006Jens Peter H. Lauritsen Summary:, During thymopoiesis, two major types of mature T cells are generated that can be distinguished by the clonotypic subunits contained within their T-cell receptor (TCR) complexes: ,, T cells and ,, T cells. Although there is no consensus as to the exact developmental stage where ,, and ,, T-cell lineages diverge, ,, T cells and precursors to the ,, T-cell lineage (bearing the pre-TCR) are thought to be derived from a common CD4,CD8, double-negative precursor. The role of the TCR in ,,/,, lineage commitment has been controversial, in particular whether different TCR isotypes intrinsically favor adoption of the corresponding lineage. Recent evidence supports a signal strength model of lineage commitment, whereby stronger signals promote ,, development and weaker signals promote adoption of the ,, fate, irrespective of the TCR isotype from which the signals originate. Moreover, differences in the amplitude of activation of the extracellular signal-regulated kinase- mitogen-activated protein kinase-early growth response pathway appear to play a critical role. These findings will be placed in context of previous analyses in an effort to more precisely define the signals that control T-lineage fate during thymocyte development. [source] Skeletal Myoblast Transplant in Heart FailureJOURNAL OF CARDIAC SURGERY, Issue 4 2003Eugene K.W. Sim F.R.C.S. Heart transplantation has emerged as a viable option but is fraught with problems of supply. Mechanical assist devices are extremely expensive and dynamic cardiomyoplasty has shown only limited success in the clinical setting. Recent insights into the pathogenesis of myocardial diseases and the progress made in the field of molecular biology have resulted in the development of new strategies at molecular as well as cellular levels for cardiac muscle repair. One such strategy is to augment ventricular function by means of cellular cardiomyoplasty through intracardiac cell grafting using adult and fetal cardiomyocytes, stem cells, and autologous skeletal myoblasts. (J Card Surg 2003; 18:319-327) [source] Recent insights into R gene evolutionMOLECULAR PLANT PATHOLOGY, Issue 5 2006JOHN M. MCDOWELL SUMMARY Plants are under strong evolutionary pressure to maintain surveillance against pathogens. Resistance (R) gene-dependent recognition of pathogen avirulence (Avr) determinants plays a major role in plant defence. Here we highlight recent insights into the molecular mechanisms and selective forces that drive the evolution of NB-LRR (nucleotide binding-leucine-rich repeat) resistance genes. New implications for models of R gene evolution have been raised by demonstrations that R proteins can detect cognate Avr proteins indirectly by ,guarding' virulence targets, and by evidence that R protein signalling is regulated by intramolecular interactions between different R functional domains. Comparative genomic surveys of NB-LRR diversity in different species have revealed ancient NB-LRR lineages that are unequally represented among plant taxa, consistent with a Birth and Death Model of evolution. The physical distribution of NB-LRRs in plant genomes indicates that tandem and segmental duplication are important factors in R gene proliferation. The majority of R genes reside in clusters, and the frequency of recombination between clustered genes can vary strikingly, even within a single cluster. Biotic and abiotic factors have been shown to increase the frequency of recombination in reporter transgene-based assays, suggesting that external stressors can affect genome stability. Fitness penalties have been associated with some R genes, and population studies have provided evidence for maintenance of ancient R allelic diversity by balancing selection. The available data suggest that different R genes can follow strikingly distinct evolutionary trajectories, indicating that it will be difficult to formulate universally applicable models of R gene evolution. [source] Update on the neurology of Parkinson's disease,NEUROUROLOGY AND URODYNAMICS, Issue 1 2007Clare J. Fowler Abstract The differential diagnosis of a patient with apparent Parkinson's Disease (PD) and bladder symptoms is considered and the bladder dysfunction of Multiple System Atrophy (MSA) is reviewed. Recent insights into the progression of the neuropathology of PD have enabled thinking about the stage of the disease at which bladder dysfunction is likely to occur and the expected clinical context of the problem. Bladder symptoms of neurological origin are likely in a patient who has had treated motor symptoms for some years and in whom the ongoing neuropathology has progressed beyond involvement of the basal ganglia, so that symptoms due to cortical dysfunction as well as the adverse effects of dopaminergic medication are also confounding factors. Bladder symptoms in a man with lesser neurological disability should be investigated to exclude underlying outflow obstruction. Possible management options are considered. Neurourol. Urodynam. © 2006 Wiley-Liss, Inc. [source] Recent insights into host,pathogen interactions from DictyosteliumCELLULAR MICROBIOLOGY, Issue 3 2010Margaret Clarke Summary To protect themselves from predation by amoebae and protozoa in the natural environment, some bacteria evolved means of escaping killing. The same mechanisms allow survival in mammalian phagocytes, producing opportunistic human pathogens. The social amoeba Dictyostelium discoideum is a powerful system for analysis of conserved host,pathogen interactions. This report reviews recent insights gained for several bacterial pathogens using Dictyostelium as host. [source] Recent insights into the mechanisms of Chlamydia entryCELLULAR MICROBIOLOGY, Issue 12 2005Alice Dautry-Varsat Summary Chlamydia are widespread bacteria that grow in human and animal cells. They enter their host cell, establish an intracellular environment favourable for their multiplication and finally exit the host cell. A combination of host cell factors and of bacterial proteins contribute to pathogen entry. Recent advances have shed new light on the entry mechanism, following attachment. Here we review recent data concerning endocytosis, host cell signalling, proteins secreted by the bacteria, the actin cytoskeleton in entry and the involvement of small GTPases. [source] Recent insights into the role of Toll-like receptors in viral infectionCLINICAL & EXPERIMENTAL IMMUNOLOGY, Issue 3 2010M. Carty Summary Toll-like receptors (TLRs) have a central role in innate immunity as they detect conserved pathogen-associated molecular patterns (PAMPs) on a range of microbes, including viruses, leading to innate immune activation and orchestration of the adaptive immune response. To date, a large number of viruses have been shown to trigger innate immunity via TLRs, suggesting that these receptors are likely to be important in the outcome to viral infection. This suggestion is supported by the observation that many viruses have evolved mechanisms not only to evade the innate immune system, but also to subvert it for the benefit of the virus. In this review we will discuss earlier evidence, mainly from knock-out mice studies, implicating TLRs in the innate immune response to viruses, in light of more recent clinical data demonstrating that TLRs are important for anti-viral immunity in humans. [source] How Elephants are Opening Doors: Developmental Neuroethology, Attachment and Social ContextETHOLOGY, Issue 5 2007G. A. Bradshaw Ethology's renewed interest in developmental context coincides with recent insights from neurobiology and psychology on early attachment. Attachment and social learning are understood as fundamental mechanisms in development that shape core processes responsible for informing behaviour throughout a lifetime. Each field uniquely contributes to the creation of an integrated model and encourages dialogue between Tinbergen's four analytical levels: ethology in its underscoring of social systems of behaviour and context, psychology in its emphasis on socio-affective attachment transactions, and neuroscience in its explication of the coupled development of brain and behaviour. We review the relationship between developmental context and behaviour outcome as a topic shared by the three disciplines, with a specific focus on underlying neuroethological mechanisms. This interdisciplinary convergence is illustrated through the example of abnormal behaviour in wild African elephants (Loxodonta africana) that has been systematically observed in human-caused altered social contexts. Such disruptions impair normative socially mediated neuroendocrinological development leading to psychobiological dysregulation that expresses as non-normative behaviour. Aberrant behaviour in wild elephants provides a critical field example of what has been established in ex situ and clinical studies but has been largely absent in wild populations: a concrete link between effects of human disturbance on social context, and short- and long-term neuroethology. By so doing, it brings attention to the significant change in theories of behaviour that has been occurring across disciplines , namely, the merging of psychobiological and ethological perspectives into common, cross-species, human inclusive models. [source] Mast cells: novel clinical perspectives from recent insightsEXPERIMENTAL DERMATOLOGY, Issue 5 2009Manfred Kneilling Abstract:, Mast cells are still generally viewed as mediators of type I allergic or pseudoallergic reactions. Research over the past 10 years revealed that our view was too small and that mast cells are of key importance in innate immunity and also types II, III and IV adaptive immune reactions. Understanding their role in modulating and amplifying of inflammatory responses provides important insights into the pathogenesis of skin diseases such as psoriasis, atopic dermatitis, bullous pemphigoid or the control of infections. This helps us to understand the course of these diseases, their trigger mechanisms, and, the new role of agents, which can modulate the function of mast cells. These insights will help to develop new therapeutic approaches. [source] Hypoxia-inducible factor as a physiological regulatorEXPERIMENTAL PHYSIOLOGY, Issue 6 2005Patrick H. Maxwell Hypoxia-inducible factor (HIF) is a transcription complex which responds to changes in oxygen, providing cells with a master regulator that coordinates changes in gene transcription. HIF operates in all mammalian cell types and is ancient in evolutionary terms, being conserved in C. elegans and D. melanogaster. This review summarizes recent insights into the molecular events that link reduced oxygenation to HIF activation and emerging insights into the extensive role of HIF in a broad range of physiological processes. [source] Radicalism in Civil War and Interregnum EnglandHISTORY COMPASS (ELECTRONIC), Issue 2 2010Philip Baker In recent decades, the subject of civil war and interregnum radicalism has provoked a vexed and tendentious scholarship within early modern English history. This article charts the subject's historiographical fortunes since the 1970s and addresses a series of crucial interpretive and definitional issues. In addition to providing an overview of the existing field, the article also suggests a new approach to mid-17th-century radicalism that encompasses a much broader spectrum of individuals, groups and ideas than those found in both Marxist and revisionist accounts. Drawing on this approach and the recent insights of other scholars, this article identifies a number of possible avenues for future research and suggests how the subject might be developed in original ways. [source] Towards integrating tracer studies in conceptual rainfall-runoff models: recent insights from a sub-arctic catchment in the Cairngorm Mountains, ScotlandHYDROLOGICAL PROCESSES, Issue 2 2003Chris Soulsby Abstract Hydrochemical tracers (alkalinity and silica) were used in an end-member mixing analysis (EMMA) of runoff sources in the 10 km2 Allt a' Mharcaidh catchment. A three-component mixing model was used to separate the hydrograph and estimate, to a first approximation, the range of likely contributions of overland flow, shallow subsurface storm flow, and groundwater to the annual hydrograph. A conceptual, catchment-scale rainfall-runoff model (DIY) was also used to separate the annual hydrograph in an equivalent set of flow paths. The two approaches produced independent representations of catchment hydrology that exhibited reasonable agreement. This showed the dominance of overland flow in generating storm runoff and the important role of groundwater inputs throughout the hydrological year. Moreover, DIY was successfully adapted to simulate stream chemistry (alkalinity) at daily time steps. Sensitivity analysis showed that whilst a distinct groundwater source at the catchment scale could be identified, there was considerable uncertainty in differentiating between overland flow and subsurface storm flow in both the EMMA and DIY applications. Nevertheless, the study indicated that the complementary use of tracer analysis in EMMA can increase the confidence in conceptual model structure. However, conclusions are restricted to the specific spatial and temporal scales examined. Copyright © 2003 John Wiley & Sons, Ltd. [source] Langerhans cell histiocytosis: fascinating dynamics of the dendritic cell,macrophage lineageIMMUNOLOGICAL REVIEWS, Issue 1 2010R. Maarten Egeler Summary:, In its rare occurrence, Langerhans cell histiocytosis (LCH) is a dangerous but intriguing deviation of mononuclear phagocytes, especially dendritic cells (DCs). Clinically, the disease ranges from self-resolving or well manageable to severe and even fatal. LCH lesions in skin, bone, and other sites contain high numbers of cells with phenotypic features resembling LCs admixed with macrophages, T cells, eosinophils, and multinucleated giant cells. Here we review current progress in the LCH field based on two central questions: (i) are LCH cells intrinsically aberrant, and (ii) how does the lesion drive pathogenesis? We argue that LCH cells may originate from different sources, including epidermal LCs, tissue Langerin+ DCs, or mononuclear phagocyte precursors. Current and prospective in vitro and in vivo models are discussed. Finally, we discuss recent insights into plasticity of T-helper cell subsets in light of the lesion microenvironment. LCH continues to provide urgent clinical questions thereby inspiring innovative DC lineage research. [source] Exposure modeling on a river basin scale in support of risk assessment for chemicals in european river basinsINTEGRATED ENVIRONMENTAL ASSESSMENT AND MANAGEMENT, Issue 1 2009Jos van Gils Abstract Following the 2000 European Water Framework Directive and recent insights into sediment management on a river basin scale, we discuss in this paper an exposure model aiming to support a risk assessment for chemicals on a basin-wide scale. It establishes spatial relations between causes (pollution sources) and effects (ecological risk), taking into account the geometry, hydrology, and fine sediment dynamics of European river basins. The model, called EXPOBASIN, explicitly takes into account the interaction of chemicals with fine sediment particles, which is important for many policy-relevant chemicals, such as trace metals and polycyclic aromatic hydrocarbons, and it addresses the potential release of historically polluted sediments as a result of extreme floods, which is a major concern in different European river basins. Bioavailability and bioaccumulation are included in the assessment. As a result, the exposure can be quantified not only in terms of water concentrations, but also in terms of sediment concentrations and concentrations in biota. The primary question to be answered by EXPOBASIN is how chemicals, pollution sources, or both rank quantitatively and objectively on a basin-wide scale. Near the end of 2009, the tool will become available to all European water managers and their technical advisors, as a result of the European Union 6th Framework Programme project MODELKEY The calibration and validation of EXPOBASIN has only just started and will be completed in 2008/2009. Applications to 3 case study areas are planned in this respect. This paper presents the key building blocks of EXPOBASIN and shows some sample results illustrating the raking of pollution sources and chemicals. At the end of the paper, some perspectives for future developments are outlined. [source] Lymphatics at the crossroads of angiogenesis and lymphangiogenesisJOURNAL OF ANATOMY, Issue 6 2004Claudio Scavelli Abstract The lymphatic system is implicated in interstitial fluid balance regulation, immune cell trafficking, oedema and cancer metastasis. However, the sequence of events that initiate and coordinate lymphatic vessel development (lymphangiogenesis) remains obscure. In effect, the understanding of physiological regulation of lymphatic vasculature has been overshadowed by the greater emphasis focused on angiogenesis, and delayed by a lack of specific markers, thereby limiting this field to no more than a descriptive characterization. Recently, new insights into lymphangiogenesis research have been due to the discovery of lymphatic-specific markers and growth factors of vascular endothelial growth factor (VEGF) family, such as VEGF-C and VEGF-D. Studies using transgenic mice overexpressing VEGF-C and VEGF-D have demonstrated a crucial role for these factors in tumour lymphangiogenesis. Knowledge of lymphatic development has now been redefined at the molecular level, providing an interesting target for innovative therapies. This review highlights the recent insights and advances into the field of lymphatic vascular research, outlining the most important aspects of the embryo development, structure, specific markers and methods applied for studying lymphangiogenesis. Finally, molecular mechanisms involved in the regulation of lymphangiogenesis are described. [source] Decreased oxidative stress and greater bone anabolism in the aged, when compared to the young, murine skeleton with parathyroid hormone administrationAGING CELL, Issue 5 2010Robert L. Jilka Summary Because of recent insights into the pathogenesis of age-related bone loss, we investigated whether intermittent parathyroid hormone (PTH) administration antagonizes the molecular mechanisms of the adverse effects of aging on bone. Parathyroid hormone produced a greater increase in vertebral trabecular bone mineral density and bone volume as well as a greater expansion of the endocortical bone surface in the femur of 26- when compared to 6 -month-old female C57BL/6 mice. Moreover, PTH increased trabecular connectivity in vertebrae, and the toughness of both vertebrae and femora in old, but not young, mice. Parathyroid hormone also increased the rate of bone formation and reduced osteoblast apoptosis to a greater extent in the old mice. Most strikingly, PTH reduced reactive oxygen species, p66Shc phosphorylation, and expression of the lipoxygenase Alox15, and it increased glutathione and stimulated Wnt signaling in bone of old mice. Parathyroid hormone also antagonized the effects of oxidative stress on p66Shc phosphorylation, Forkhead Box O transcriptional activity, osteoblast apoptosis, and Wnt signaling in vitro. In contrast, administration of the antioxidants N -acetyl cysteine or pegylated catalase reduced osteoblast progenitors and attenuated proliferation and Wnt signaling. These results suggest that PTH has a greater bone anabolic efficacy in old age because in addition to its other positive actions on bone formation, it antagonizes the age-associated increase in oxidative stress and its adverse effects on the birth and survival of osteoblasts. On the other hand, ordinary antioxidants cannot restore bone mass in old age because they slow remodeling and attenuate osteoblastogenesis by interfering with Wnt signaling. [source] The neuronal MAP kinase cascade: a biochemical signal integration system subserving synaptic plasticity and memoryJOURNAL OF NEUROCHEMISTRY, Issue 1 2001J. David Sweatt The mitogen-activated protein kinase (MAP kinase, MAPK) cascade, as the name implies, was originally discovered as a critical regulator of cell division and differentiation. As further details of this signaling cascade were worked out, it became clear that the MAPK cascade is in fact a prototype for a family of signaling cascades that share the motif of three serially linked kinases regulating each other by sequential phosphorylation. Thus, a revised nomenclature arose that uses the term MAPK to refer to the entire superfamily of signaling cascades (comprising the erks, the JNKs and the p38 stress activated protein kinases), and specifies the prototype MAPK as the extracellular signal-regulated kinase (erk). The two erk MAPK isoforms, p44 MAPK and p42 MAPK, are referred to as erk1 and erk2, respectively. The erks are abundantly expressed in neurons in the mature central nervous system, raising the question of why the prototype molecular regulators of cell division and differentiation are present in these non-dividing, terminally differentiated neurons. This review will describe the beginnings of an answer to this question. Interestingly, the general model has begun to emerge that the erk signaling system has been co-opted in mature neurons to function in synaptic plasticity and memory. Moreover, recent insights have led to the intriguing prospect that these molecules serve as biochemical signal integrators and molecular coincidence detectors for coordinating responses to extracellular signals in neurons. In this review I will first outline the essential components of this signal transduction cascade, and briefly describe recent results implicating the erks in mammalian synaptic plasticity and learning. I will then proceed to outline recent results implicating the erks as molecular signal integrators and, potentially, coincidence detectors. Finally, I will speculate on what the critical downstream effectors of the erks are in neurons, and how they might provide a readout of the integrated signal. [source] Lamp light on leadership: clinical leadership and Florence NightingaleJOURNAL OF NURSING MANAGEMENT, Issue 2 2010BA Ng, DAVID STANLEY NursD, Dip HE (Nursing) stanley d. & sherratt a. (2010) Journal of Nursing Management 18, 115,121 Lamp light on leadership: clinical leadership and Florence Nightingale Aims, The purpose of the present study was to use the example of Florence Nightingales' nursing experience to highlight the differences between nursing leadership and clinical leadership with a focus on Miss Nightingales' clinical leadership attributes. Background, 2010 marks the centenary of the death of Florence Nightingale. As this significant date approaches this paper reflects on her contribution to nursing in relation to more recent insights into clinical leadership. Evaluation, Literature has been used to explore issues related to nursing leadership, clinical leadership and the life and characteristics of Florence Nightingale. Key issues, There are a few parts of Florence's character which fit the profile of a clinical leader. However, Miss Nightingale was not a clinical leader she was a powerful and successful role model for the academic, political and managerial domains of nursing. Conclusion, There are other ways to lead and other types of leaders and leadership that nursing and the health service needs to foster, discover and recognize. Implications for nursing management, Clinical leaders should be celebrated and recognized in their own right. Both clinical leaders and nursing leaders are important and need to work collaboratively to enhance patient care and to positively enhance the profession of nursing. [source] Recent insights into R gene evolutionMOLECULAR PLANT PATHOLOGY, Issue 5 2006JOHN M. MCDOWELL SUMMARY Plants are under strong evolutionary pressure to maintain surveillance against pathogens. Resistance (R) gene-dependent recognition of pathogen avirulence (Avr) determinants plays a major role in plant defence. Here we highlight recent insights into the molecular mechanisms and selective forces that drive the evolution of NB-LRR (nucleotide binding-leucine-rich repeat) resistance genes. New implications for models of R gene evolution have been raised by demonstrations that R proteins can detect cognate Avr proteins indirectly by ,guarding' virulence targets, and by evidence that R protein signalling is regulated by intramolecular interactions between different R functional domains. Comparative genomic surveys of NB-LRR diversity in different species have revealed ancient NB-LRR lineages that are unequally represented among plant taxa, consistent with a Birth and Death Model of evolution. The physical distribution of NB-LRRs in plant genomes indicates that tandem and segmental duplication are important factors in R gene proliferation. The majority of R genes reside in clusters, and the frequency of recombination between clustered genes can vary strikingly, even within a single cluster. Biotic and abiotic factors have been shown to increase the frequency of recombination in reporter transgene-based assays, suggesting that external stressors can affect genome stability. Fitness penalties have been associated with some R genes, and population studies have provided evidence for maintenance of ancient R allelic diversity by balancing selection. The available data suggest that different R genes can follow strikingly distinct evolutionary trajectories, indicating that it will be difficult to formulate universally applicable models of R gene evolution. [source] Ustilago maydis, model system for analysis of the molecular basis of fungal pathogenicityMOLECULAR PLANT PATHOLOGY, Issue 2 2004Christoph W. Basse SUMMARY Ustilago maydis, a facultative biotrophic basidiomycete fungus, causes smut disease in maize. A hallmark of this disease is the induction of large plant tumours that are filled with masses of black-pigmented teliospores. During the last 15 years U. maydis has become an important model system to unravel molecular mechanisms of fungal phytopathogenicity. This review highlights recent insights into molecular mechanisms of complex signalling pathways that are involved in the transition from budding to filamentous growth and operate during the pathogenic growth phase. In addition, we describe recent progress in understanding the structural basis of morphogenesis and polar growth in different stages of U. maydis development. Finally, we present an overview of recently identified genes related to pathogenic development and summarize novel molecular and genomic approaches that are powerful tools to explore the genetic base of pathogenicity. Taxonomy: Ustilago maydis (DC) Corda (synonymous with Ustilago zeae Ung.)-Kingdom Eukaryota, Phylum Fungi, Order Basidiomycota, Family Ustilaginomycetes, Genus Ustilago. Host range: Infects aerial parts of corn plants (Zea mays) and its progenitor teosinte (Zea mays ssp. parviglumis). Maize smut is distributed throughout the world. Disease symptoms: U. maydis causes chlorotic lesions in infected areas, the formation of anthocyanin pigments, necrosis, hyperplasia and hypertrophy of infected organs. Infection by U. maydis can inhibit development and lead to stunting of infected plants. A few days after infection plant tumours develop in which massive fungal proliferation and the formation of the black-pigmented, diploid teliospores occurs. Under natural conditions tumours predominantly develop on sexual organs (tassels and ears), stems and nodal shoots. Tumours may vary in size from minute pustules to several centimetres in diameter and contain up to 200 billion spores. Useful web site: http://www-genome.wi.mit.edu/annotation/fungi/ustilago_maydis/ [source] Falls and freezing of gait in Parkinson's disease: A review of two interconnected, episodic phenomenaMOVEMENT DISORDERS, Issue 8 2004Bastiaan R. Bloem MD Abstract Falls and freezing of gait are two "episodic" phenomena that are common in Parkinson's disease. Both symptoms are often incapacitating for affected patients, as the associated physical and psychosocial consequences have a great impact on the patients' quality of life, and survival is diminished. Furthermore, the resultant loss of independence and the treatment costs of injuries add substantially to the health care expenditures associated with Parkinson's disease. In this clinically oriented review, we summarise recent insights into falls and freezing of gait and highlight their similarities, differences, and links. Topics covered include the clinical presentation, recent ideas about the underlying pathophysiology, and the possibilities for treatment. A review of the literature and the current state-of-the-art suggests that clinicians should not feel deterred by the complex nature of falls and freezing of gait; a careful clinical approach may lead to an individually tailored treatment, which can offer at least partial relief for many affected patients. © 2004 Movement Disorder Society [source] Eosinophilic oesophagitis in adultsNEUROGASTROENTEROLOGY & MOTILITY, Issue 10 2009N. Gonsalves Abstract, Previously considered a rare condition, eosinophilic oesophagitis (EoE) has become increasingly recognized as an important cause of dysphagia and food impactions in adults. This is likely attributable to a combination of an increasing incidence of EoE and a growing awareness of the condition. EoE may occur in isolation or in conjunction with eosinophilic gastroenteritis. However, the burgeoning field is likely attributable to the variant that uniquely affects the oesophagus. Adults classically present with symptoms of dysphagia, food impactions, and heartburn. Typical endoscopic features include concentric mucosal rings, linear furrowing, white plaques or exudates and a narrow caliber oesophagus. In some cases, the endoscopic features may appear normal. For years, EoE went unrecognized because eosinophilic infiltration was accepted as a manifestation of reflux, which continues to be a confounding factor in some patients. Current consensus is that the diagnosis of EoE is established by 1) the presence of symptoms, especially dysphagia and food impactions in adults, 2) ,15 eosinophils per high power field in oesophageal tissue, and 3) exclusion of other disorders with similar presentations such as GERD. Current understanding of EoE pathophysiology and natural history are limited but the entity has been increasingly linked to food allergies and aeroallergens. The main treatment options for EoE are proton pump inhibitors, dietary manipulation, and topical or oral glucocorticoids. This review highlights recent insights into EoE in adults although, clearly, much of the available data overlap with pediatrics and, occasionally, with eosinophilic gastroenteritis. [source] Breeding habitat selection behaviors in heterogeneous environments: implications for modeling reintroductionOIKOS, Issue 5 2009Jean-Baptiste Mihoub Animal movement and habitat selection behavior are important considerations in ecology, and remain a major issue for successful animal reintroductions. However, simple rules are often used to model movement or focus only on intrinsic environmental cues, neglecting recent insights in behavioral ecology on habitat selection processes. In particular, social information has been proposed as a widespread source of information for habitat evaluation. We investigated the role of explicit breeding habitat selection strategies on the establishment pattern of reintroduced populations and their persistence. We considered local movement at the scale of a single population. We constructed a spatially-implicit demographic model that considered five breeding habitat selection rules: 1) random, 2) intrinsic habitat quality, 3) avoidance of conspecifics, 4) presence of conspecifics and 5) reproductive success of conspecifics. The impact of breeding habitat selection was examined for different release methods under various levels of environmental heterogeneity levels, for both long and short-lived monogamous species. When heterogeneity between intrinsic habitat patch qualities is high, the persistence of reintroduced populations strongly depends on habitat selection strategies. Strategies based on intrinsic quality and conspecific reproductive success lead to a lower reintroduction failure risk than random, conspecific presence or avoidance-based strategies. Conspecific presence or avoidance-based strategies may aggregate individuals in suboptimal habitats. The release of adults seems to be more efficient independent of habitat selection strategy. We emphasize the crucial role of oriented habitat selection behavior and non ideal habitat selection in movement modeling, particularly for reintroduction. [source] Genesis of teratogen-induced holoprosencephaly in mice,AMERICAN JOURNAL OF MEDICAL GENETICS, Issue 1 2010Robert J. Lipinski Abstract Evidence from mechanical, teratological, and genetic experimentation demonstrates that holoprosencephaly (HPE) typically results from insult prior to the time that neural tube closure is completed and occurs as a consequence of direct or indirect insult to the rostral prechordal cells that induce the forebrain or insult to the median forebrain tissue, itself. Here, we provide an overview of normal embryonic morphogenesis during the critical window for HPE induction, focusing on the morphology and positional relationship of the developing brain and subjacent prechordal plate and prechordal mesoderm cell populations. Subsequent morphogenesis of the HPE spectrum is then examined in selected teratogenesis mouse models. The temporal profile of Sonic Hedgehog expression in rostral embryonic cell populations and evidence for direct or indirect perturbation of the Hedgehog pathway by teratogenic agents in the genesis of HPE is highlighted. Emerging opportunities based on recent insights and new techniques to further characterize the mechanisms and pathogenesis of HPE are discussed. © 2010 Wiley-Liss, Inc. [source] |