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Current Understanding (current + understanding)
Selected AbstractsOur Current Understanding of the Impact of Aerosols on Climate ChangeCHEMSUSCHEM CHEMISTRY AND SUSTAINABILITY, ENERGY & MATERIALS, Issue 5 2009Kimberly Abstract Aerosols constitute a climate and health risk via both direct and indirect effects. In this Viewpoint, recent developments in aerosol research and available instrumentation are discussed in the context of environmental change. [source] Mouse Th17 cells: Current understanding of their generation and regulationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2009Chen Dong Abstract IL-17-expressing CD4+ T cells have been recently recognized as a new subset of Th cells, namely Th17 cells. Considerable progress has been made in understanding the developmental regulation of mouse Th17 cells. Here, I summarize this knowledge and discuss on the relationship of Th17 with regulatory and follicular Th cells. [source] Cardiovascular Risk Assessment and TriptansHEADACHE, Issue 2004Vasilios Papademetriou MD Identifying the patient for whom triptans are contraindicated because of recognized, diagnosed cardiovascular disease is relatively straightforward. Determining whether a patient with potential unrecognized cardiovascular disease is an appropriate candidate for triptan therapy, however, constitutes a difficult challenge, especially in the absence of a framework for workup of patients. This article discusses the pathophysiology of coronary heart disease and issues involved in assessing cardiovascular risk, and it attempts to provide a framework for cardiovascular risk assessment that can be applied to decisions for prescribing triptans. Current guidelines for cardiovascular risk assessment allow stratification of patients to low, intermediate, or high risk of coronary heart disease events. This framework for risk assessment can be applied to decisions for prescribing triptans. Cardiovascular risk-assessment algorithms discussed elsewhere in this supplement suggest that patients at low risk (1 or no risk factors) of coronary heart disease can be prescribed triptans without the need for a more intensive cardiovascular evaluation. Conversely, patients with established coronary heart disease or coronary heart disease risk equivalents should not be prescribed triptans according to the current prescribing recommendations. Patients at intermediate risk (2 or more risk factors) of coronary heart disease require cardiovascular evaluation before triptans can be prescribed. Current understanding suggests that the risk of future acute coronary events is a function of the absolute number of vulnerable plaques present, a variable that cannot be accurately determined using available technology or risk-prediction models. Cardiovascular risk-assessment guidelines should be evaluated in the context of this limitation. [source] Current understanding and management of hidradenitis suppurativaJOURNAL OF THE AMERICAN ACADEMY OF NURSE PRACTITIONERS, Issue 5 2007Amanda C Krbec MSN, BC (Capt, Family Nurse Practitioner), Nurse Corps, United States Air Force Abstract Purpose: To review the diagnosis and treatment of hidradenitis suppurativa (HS) in primary care. Data sources: Review of current literature from journals and textbooks as well as clinical experience. Conclusions: HS, a chronic disease causing scarring and pus formation to the skin bearing apocrine glands, requires continual management by the primary care manager and often deems referral to a dermatologist or surgeon. Implications for practice: If misdiagnosed or poorly managed, HS has detrimental effects on patients' quality of life and self-esteem. [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] Termites and fire: Current understanding and future research directions for improved savanna conservationAUSTRAL ECOLOGY, Issue 4 2010ANDREW B. DAVIES First page of article [source] The Structure of Glycosaminoglycans and their Interactions with ProteinsCHEMICAL BIOLOGY & DRUG DESIGN, Issue 6 2008Neha S. Gandhi Glycosaminoglycans (GAGs) are important complex carbohydrates that participate in many biological processes through the regulation of their various protein partners. Biochemical, structural biology and molecular modelling approaches have assisted in understanding the molecular basis of such interactions, creating an opportunity to capitalize on the large structural diversity of GAGs in the discovery of new drugs. The complexity of GAG,protein interactions is in part due to the conformational flexibility and underlying sulphation patterns of GAGs, the role of metal ions and the effect of pH on the affinity of binding. Current understanding of the structure of GAGs and their interactions with proteins is here reviewed: the basic structures and functions of GAGs and their proteoglycans, their clinical significance, the three-dimensional features of GAGs, their interactions with proteins and the molecular modelling of heparin binding sites and GAG,protein interactions. This review focuses on some key aspects of GAG structure,function relationships using classical examples that illustrate the specificity of GAG,protein interactions, such as growth factors, anti-thrombin, cytokines and cell adhesion molecules. New approaches to the development of GAG mimetics as possible new glycotherapeutics are also briefly covered. [source] The eye in focus: accommodation and presbyopiaCLINICAL AND EXPERIMENTAL OPTOMETRY, Issue 3 2008W Neil Charman DSc PhD Current understanding of the anatomy, function and performance of the accommodative system of the young, adult human eye is outlined. Most major current models of the accommodative mechanism are based on Helmholtz's original ideas but, despite of a growing volume of related research, uncertainty continues over the relative contributions made to the overall mechanism by different ocular structures. The changes with age are then discussed. Although the amplitude of accommodation decreases steadily from later childhood, the speed and accuracy of the system within the available amplitude are little impaired until the age of about 40, when the amplitude falls below that needed for normal near work. A review of the available evidence on age-related change in the lens, capsule, ciliary body and other relevant ocular structures confirms that geometric and viscoelastic lenticular changes play major roles in the progressive loss of accommodation. Other factors may also contribute in an, as yet, unquantified way and a full understanding of the origins of presbyopic change remains elusive. [source] The effects of acute and chronic exercise on the vasculatureACTA PHYSIOLOGICA, Issue 4 2010J. J. Whyte Abstract Regular physical activity (endurance training, ET) has a strong positive link with cardiovascular health. The aim of this review is to draw together the current knowledge on gene expression in different cell types comprising the vessels of the circulatory system, with special emphasis on the endothelium, and how these gene products interact to influence vascular health. The effect beneficial effects of ET on the endothelium are believed to result from increased vascular shear stress during ET bouts. A number of mechanosensory mechanisms have been elucidated that may contribute to the effects of ET on vascular function, but there are questions regarding interactions among molecular pathways. For instance, increases in flow brought on by ET can reduce circulating levels of viscosity and haemostatic and inflammatory variables that may interact with increased shear stress, releasing vasoactive substances such as nitric oxide and prostacyclin, decreasing permeability to plasma lipoproteins as well as the adhesion of leucocytes. At this time the optimal rate-of-flow and rate-of-change in flow for determining whether anti-atherogenic or pro-atherogenic processes proceed remain unknown. In addition, the impact of haemodynamic variables differs with vessel size and tissue type in which arteries are located. While the hurdles to understanding the mechanism responsible for ET-induced alterations in vascular cell gene expression are significant, they in no way undermine the established benefits of regular physical activity to the cardiovascular system and to general overall health. This review summarizes current understanding of control of vascular cell gene expression by exercise and how these processes lead to improved cardiovascular health. [source] Impact of National Aquarium in Baltimore on Visitors' Conservation Attitudes, Behavior, and KnowledgeCURATOR THE MUSEUM JOURNAL, Issue 1 2000LESLIE M. ADELMAN ABSTRACT This study at the National Aquarium in Baltimore (NAIB) was conducted to assess four key aspects of the visitor experience: (1) incoming conservation knowledge, attitudes, and behavior of NAIB visitors; (2) patterns of use and interaction with exhibition components throughout the NAIB; (3) exiting conservation knowledge, attitudes, and behaviors of visitors; and (4) over time, how the NAIB experience altered or affected individuals' conservation knowledge, attitudes, and behaviors. Three hundred six visitors participated in the study, which was conducted from March through July, 1999. The study utilized four data-collection techniques: (1) face-to-face interviews, (2) Personal Meaning Mapping (PMM), (3) tracking, and (4) follow-up telephone interviews. Participants were a self-selected population and were generally more knowledgeable about, more concerned about, and more involved in conservation-related issues than the general public. However, they were far from conservationists. Visitors in this study clearly absorbed the fundamental conservation message at the NAIB. In fact, the NAIB visit appeared to focus visitors' conservation-related thoughts, while also broadening their understanding of conservation. Changes in visitors' conservation knowledge, understanding, and interests by and large persisted over six to eight weeks after visiting NAIB. The NAIB experience also connected to visitors' lives in a variety of ways following their visit. However, these personal experiences rarely resulted in new conservation actions. In fact, their enthusiasm and emotional commitment to conservation (inspired during the NAIB visit) generally fell back to original levels, presumably in the absence of reinforcing experiences. The findings of this study are guiding subsequent investigations at the NAIB. More generally, the results suggest strategies to enhance current understanding of the impact free-choice learning institutions have on their visiting public. [source] Perioperative Management of Medications for Psoriasis and Psoriatic Arthritis: A Review for the DermasurgeonDERMATOLOGIC SURGERY, Issue 4 2008CLAUDIA HERNANDEZ MD BACKGROUND Psoriasis affects an estimated 3% of the world's population. Many are on chronic immunosuppressive therapy for the cutaneous and joint manifestations of this disorder. The management of these medications in the perioperative period is controversial. Psoriasis and psoriatic arthritis medications can affect wound healing, hemostasis, and infection risk during cutaneous surgery. OBJECTIVES The objective of this article is to provide a critical review of various medications used for care of the psoriatic patient and their potential effect on cutaneous surgical procedures. CONCLUSIONS This review summarizes current understanding of wound healing, hemostatic effects, and infectious risks regarding many psoriasis medications including nonsteroidal anti-inflammatory drugs, cyclooxygenase inhibitors, corticosteroids, various immunosuppressants, and biologic response modifiers. Recommendations vary depending on the agent in question, type of procedure, and comorbid conditions in the patient. Caution is advised when using many of the medications reviewed due to lack of human data of their effects in the perioperative period. [source] Tanning and Cutaneous MalignancyDERMATOLOGIC SURGERY, Issue 4 2008SHERRIF F. IBRAHIM MD BACKGROUND Exposure to ultraviolet radiation (UVR) results in a darkening of the skin known as tanning. Recently, it has been shown that tanning is a response to UVR-induced DNA damage and represents the skin's efforts to protect itself against further injury. Despite the link between UVR and cutaneous malignancy, people continue to pursue tanning from natural and artificial sources. This trend is reflected in the exponential rise in skin cancer incidence. OBJECTIVE The objective of this study was to review our current understanding of the factors controlling the tanning response and the relationship to cutaneous carcinogenesis, as well as the impact that the multibillion dollar tanning industry has had on the practice of dermatology. MATERIALS AND METHODS Extensive literature review was conducted in subjects related to tanning and the relationship to cutaneous malignancy. RESULTS Our knowledge of tanning and its effects on the skin has increased tremendously. It is clear that tanning contributes to the development of skin cancer. Despite this information, the incidence of skin cancer continues to increase exponentially. CONCLUSIONS Skin cancer poses a major public health concern and tanning remains the most modifiable risk factor in its etiology. Social, economic, and legislative issues have become tightly intertwined with the complex nature of human behavior in the continued pursuit of an activity that clearly has detrimental effects on one's health. [source] Preimplantation development of mouse: A view from cellular behaviorDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 3 2010Toshihiko Fujimori A mature animal body contains a variety of different cell types, and these cells are distributed in a well-organized fashion along the body axes. One of the major questions in developmental biology is how cells acquire different characteristics. In addition, it is important to understand how the embryo forms the body axes and how cells are allocated along these axes during development. Among mammalian species, the molecular mechanisms that regulate embryonic development have been well analyzed and characterized in mice. Here, mouse preimplantation embryonic development is briefly summarized and our current understanding of this complex process based on recent observations is reviewed. [source] Development of three-dimensional architecture of the neuroepithelium: Role of pseudostratification and cellular ,community'DEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2008Takaki Miyata This review discusses the development of the neuroepithelium (NE) and its derivative ventricular zone (VZ), from which the central nervous system (CNS) is formed. First, the histological features of the NE and VZ are summarized, highlighting the phenomenon of pseudostratification, which is achieved by polarization and interkinetic nuclear migration (INM) of neural progenitor cells. Next, our current understanding of the cellular and molecular mechanisms and biological significance of INM and pseudostratification are outlined. The recent three-dimensional time-lapse observations revealing heterogeneity in cell lineages within the NE and VZ are also described, focusing on the neuronal lineage. Finally, the necessity of comprehensive studies on cell-cell interactions in the NE/VZ is discussed, as well as the importance of electrophysiological and biomechanical approaches. In particular, we suggest that a systems biology approach to the NE/VZ as a cellular ,community' may be fruitful. [source] The mechanism of Drosophila leg development along the proximodistal axisDEVELOPMENT GROWTH & DIFFERENTIATION, Issue 2 2004Tetsuya Kojima During development of higher organisms, most patterning events occur in growing tissues. Thus, unraveling the mechanism of how growing tissues are patterned into final morphologies has been an essential subject of developmental biology. Limb or appendage development in both vertebrates and invertebrates has attracted great attention from many researchers for a long time, because they involve almost all developmental processes required for tissue patterning, such as generation of the positional information by morphogen, subdivision of the tissue into distinct parts according to the positional information, localized cell growth and proliferation, and control of adhesivity, movement and shape changes of cells. The Drosophila leg development is a good model system, upon which a substantial amount of knowledge has been accumulated. In this review, the current understanding of the mechanism of Drosophila leg development is described. [source] Anomalous development of brain structure and function in spina bifida myelomeningoceleDEVELOPMENTAL DISABILITIES RESEARCH REVIEW, Issue 1 2010Jenifer Juranek Abstract Spina bifida myelomeningocele (SBM) is a specific type of neural tube defect whereby the open neural tube at the level of the spinal cord alters brain development during early stages of gestation. Some structural anomalies are virtually unique to individuals with SBM, including a complex pattern of cerebellar dysplasia known as the Chiari II malformation. Other structural anomalies are not necessarily unique to SBM, including altered development of the corpus callosum and posterior fossa. Within SBM, tremendous heterogeneity is reflected in the degree to which brain structures are atypical in qualitative appearance and quantitative measures of morphometry. Hallmark structural features of SBM include overall reductions in posterior fossa and cerebellum size and volume. Studies of the corpus callosum have shown complex patterns of agenesis or hypoplasia along its rostral-caudal axis, with rostrum and splenium regions particularly susceptible to agenesis. Studies of cortical regions have demonstrated complex patterns of thickening, thinning, and gyrification. Diffusion tensor imaging studies have reported compromised integrity of some specific white matter pathways. Given equally complex ocular motor, motor, and cognitive phenotypes consisting of relative strengths and weaknesses that seem to align with altered structural development, studies of SBM provide new insights to our current understanding of brain structure,function associations. © 2010 Wiley-Liss, Inc. Dev Disabil Res Rev 2010;16:23,30. [source] Morphogenesis of the node and notochord: The cellular basis for the establishment and maintenance of left,right asymmetry in the mouseDEVELOPMENTAL DYNAMICS, Issue 12 2008Jeffrey D. Lee Abstract Establishment of left,right asymmetry in the mouse embryo depends on leftward laminar fluid flow in the node, which initiates a signaling cascade that is confined to the left side of the embryo. Leftward fluid flow depends on two cellular processes: motility of the cilia that generate the flow and morphogenesis of the node, the structure where the cilia reside. Here, we provide an overview of the current understanding and unresolved questions about the regulation of ciliary motility and node structure. Analysis of mouse mutants has shown that the motile cilia must have a specific structure and length, and that they must point posteriorly to generate the necessary leftward fluid flow. However, the precise structure of the motile cilia is not clear and the mechanisms that position cilia on node cells have not been defined. The mouse node is a teardrop-shaped pit at the distal tip of the early embryo, but the morphogenetic events that create the mature node from cells derived from the primitive streak are only beginning to be characterized. Recent live imaging experiments support earlier scanning electron microscopy (SEM) studies and show that node assembly is a multi-step process in which clusters of node precursors appear on the embryo surface as overlying endoderm cells are removed. We present additional SEM and confocal microscopy studies that help define the transition stages during node morphogenesis. After the initiation of left-sided signaling, the notochordal plate, which is contiguous with the node, generates a barrier at the embryonic midline that restricts the cascade of gene expression to the left side of the embryo. The field is now poised to dissect the genetic and cellular mechanisms that create and organize the specialized cells of the node and midline that are essential for left,right asymmetry. Developmental Dynamics 237:3464,3476, 2008. © 2008 Wiley-Liss, Inc. [source] Origin and fate of cardiac mesenchymeDEVELOPMENTAL DYNAMICS, Issue 10 2008Brian S. Snarr Abstract The development of the embryonic heart is dependent upon the generation and incorporation of different mesenchymal subpopulations that derive from intra- and extra-cardiac sources, including the endocardium, epicardium, neural crest, and second heart field. Each of these populations plays a crucial role in cardiovascular development, in particular in the formation of the valvuloseptal apparatus. Notwithstanding shared mechanisms by which these cells are generated, their fate and function differ profoundly by their originating source. While most of our early insights into the origin and fate of the cardiac mesenchyme has come from experimental studies in avian model systems, recent advances in transgenic mouse technology has enhanced our ability to study these cell populations in the mammalian heart. In this article, we will review the current understanding of the role of cardiac mesenchyme in cardiac morphogenesis and discuss several new paradigms based on recent studies in the mouse. Developmental Dynamics 237:2804,2819, 2008. © 2008 Wiley-Liss, Inc. [source] Extrinsic versus intrinsic cues in avian paraxial mesoderm patterning and differentiationDEVELOPMENTAL DYNAMICS, Issue 9 2007Ingo Bothe Abstract Somitic and head mesoderm contribute to cartilage and bone and deliver the entire skeletal musculature. Studies on avian somite patterning and cell differentiation led to the view that these processes depend solely on cues from surrounding tissues. However, evidence is accumulating that some developmental decisions depend on information within the somitic tissue itself. Moreover, recent studies established that head and somitic mesoderm, though delivering the same tissue types, are set up to follow their own, distinct developmental programmes. With a particular focus on the chicken embryo, we review the current understanding of how extrinsic signalling, operating in a framework of intrinsically regulated constraints, controls paraxial mesoderm patterning and cell differentiation. Developmental Dynamics 236:2397,2409, 2007. © 2007 Wiley-Liss, Inc. [source] Vascular endothelial growth factor and diabetic retinopathy: pathophysiological mechanisms and treatment perspectivesDIABETES/METABOLISM: RESEARCH AND REVIEWS, Issue 6 2003Ruth B. Caldwell Abstract Retinal neovascularization and macular edema are central features of diabetic retinopathy, the major cause of blindness in the developed world. Current treatments are limited in their efficacy and are associated with significant adverse effects. Characterization of the molecular and cellular processes involved in vascular growth and permeability has led to the recognition that the angiogenic growth factor and vascular permeability factor vascular endothelial growth factor (VEGF) plays a pivotal role in the retinal microvascular complications of diabetes. Therefore, VEGF represents an exciting target for therapeutic intervention in diabetic retinopathy. This review highlights the current understanding of the mechanisms that regulate VEGF gene expression and mediate its biological effects and how these processes may become altered during diabetes. The cellular and molecular alterations that characterize experimental models of diabetes are considered in relation to the influence of high glucose-mediated oxidative stress on VEGF expression and on the mechanisms of VEGF's actions under hyperglycemic induction. Finally, potential therapeutic strategies for preventing VEGF overexpression or blocking its pathological effects in the diabetic retina are considered. Copyright © 2003 John Wiley & Sons, Ltd. [source] Reflux injury of esophageal mucosa: experimental studies in animal models of esophagitis, Barrett's esophagus and esophageal adenocarcinomaDISEASES OF THE ESOPHAGUS, Issue 5 2007Yan Li SUMMARY., Barrett's esophagus (BE), a gastroesophageal reflux associated complication, is defined as the replacement of normal esophageal squamous mucosa by specialized intestinal columnar mucosa with the appearance of goblet cells. The presence of BE is associated with an increased risk of developing esophageal adenocarcinoma (EAC). Although the exposure of gastroduodenal contents to the esophageal mucosa is considered to be an important risk factor for the development of esophagitis, BE and EAC, the mechanisms of reflux esophageal injury are not fully understood. Animal models are now being used extensively to identify the mechanisms of damage and to devise protective and mitigating strategies. Experimental studies on animal models by mimicking the processing of gastroesophageal reflux injury have bloomed during the past decades, however, there is controversy regarding which experimental model for reflux esophagitis, experimental BE and experimental EAC is best. In this review article we aim to clarify the basic understanding of gastroesophageal reflux injury and its complications of BE and EAC, as well as to present current understanding of the reflux experimental models. The animal models of experimental esophageal injury are summarized with focus on the surgical procedures to guide the investigator in choosing or developing a correct animal model in future studies. In addition, our own experimental studies of the animal models are also briefly discussed. [source] Stearoyl-CoA desaturase: a new therapeutic target of liver steatosisDRUG DEVELOPMENT RESEARCH, Issue 8 2006Pawel Dobrzyn Abstract Stearoyl-CoA desaturase (SCD) is the rate limiting enzyme catalyzing the biosynthesis of monounsaturated fatty acids, mainly oleate and palmitoleoate, which are used as substrates for the synthesis of triglycerides, wax esters, cholesterol esters, and phospholipids. Recent studies have shown that SCD1, the main SCD isoform expressed in liver, is a key player in the regulation of lipid metabolism. SCD1 deficient mice have increased energy expenditure, reduced body adiposity, increased insulin sensitivity and are resistant to diet-induced obesity and liver steatosis. SCD1 was found to be specifically repressed during leptin-mediated weight loss and leptin-deficient ob/ob mice lacking SCD1 showed markedly reduced adiposity, despite higher food intake. In addition, SCD1 deficiency completely corrects the hypometabolic phenotype and hepatic steatosis of ob/ob mice, and attenuates fasting-induced liver steatosis in peroxisome proliferator-activated receptor-, , deficient mice. Consequently, increased SCD activity has been found in humans and animals which accumulate significant amounts of lipids in liver, whereas SCD1 deficiency ameliorates both high-fat diet induced and genetically induced hepatic steatosis. Much evidence indicates that the direct anti-steatotic effect of SCD1 deficiency stems from increased fatty acid oxidation and reduced lipid synthesis. In this review we discuss our current understanding of the role of SCD1 in regulation of hepatic lipid partitioning and test the hypothesis that pharmacological manipulation of SCD might be of benefit in the treatment of non-alcoholic fatty liver disease. Drug Dev. Res. 67:643,650, 2006. © 2006 Wiley-Liss, Inc. [source] The metacommunity concept: a framework for multi-scale community ecologyECOLOGY LETTERS, Issue 7 2004M. A. Leibold Abstract The metacommunity concept is an important way to think about linkages between different spatial scales in ecology. Here we review current understanding about this concept. We first investigate issues related to its definition as a set of local communities that are linked by dispersal of multiple potentially interacting species. We then identify four paradigms for metacommunities: the patch-dynamic view, the species-sorting view, the mass effects view and the neutral view, that each emphasizes different processes of potential importance in metacommunities. These have somewhat distinct intellectual histories and we discuss elements related to their potential future synthesis. We then use this framework to discuss why the concept is useful in modifying existing ecological thinking and illustrate this with a number of both theoretical and empirical examples. As ecologists strive to understand increasingly complex mechanisms and strive to work across multiple scales of spatio-temporal organization, concepts like the metacommunity can provide important insights that frequently contrast with those that would be obtained with more conventional approaches based on local communities alone. [source] Shell disease in crustaceans , just chitin recycling gone wrong?ENVIRONMENTAL MICROBIOLOGY, Issue 4 2008Claire L. Vogan Summary The exoskeletons of aquatic crustaceans and other arthropods contain chitin, a biopolymer of ,-(1,4)-linked N -acetylglucosamine together with associated proteins. Despite the vast amounts of chitin within such animals little is found in sediments and open water because microorganisms rapidly degrade this following its loss after moulting or upon the animals' death. Shell disease syndrome is a worldwide disease condition that affects a wide range of crustaceans. It comes about as a result of bacterial degradation of the exoskeleton leading to unsightly lesions and even death if the underlying tissues become infected. There are at least two potential forms of the disease; one that appears to centre around chitin degradation and an additional form termed ,epizootic' shell disease, in which chitin degradation is of less significance. This account reviews our current understanding of the causative agents of this syndrome, assesses the potential economic consequences of the disease, and critically examines whether it is associated with anthropogenic disturbances including pollution. Overall, despite extensive studies during the last few decades, the potential links between faecal, heavy metal and insecticide pollution and shell disease are still unclear. [source] The Influence of Gonadal Hormones on Neuronal Excitability, Seizures, and Epilepsy in the FemaleEPILEPSIA, Issue 9 2006Helen E. Scharfman Summary:, It is clear from both clinical observations of women, and research in laboratory animals, that gonadal hormones exert a profound influence on neuronal excitability, seizures, and epilepsy. These studies have led to a focus on two of the primary ovarian steroid hormones, estrogen and progesterone, to clarify how gonadal hormones influence seizures in women with epilepsy. The prevailing view is that estrogen is proconvulsant, whereas progesterone is anticonvulsant. However, estrogen and progesterone may not be the only reproductive hormones to consider in evaluating excitability, seizures, or epilepsy in the female. It seems unlikely that estrogen and progesterone would exert single, uniform actions given our current understanding of their complex pharmacological and physiological relationships. Their modulatory effects are likely to depend on endocrine state, relative concentration, metabolism, and many other factors. Despite the challenges these issues raise to future research, some recent advances have helped clarify past confusion in the literature. In addition, testable hypotheses have developed for complex clinical problems such as "catamenial epilepsy." Clinical and animal research, designed with the relevant endocrinological and neurobiological issues in mind, will help advance this field in the future. [source] The science of endothelin-1 and endothelin receptor antagonists in the management of pulmonary arterial hypertension: current understanding and future studiesEUROPEAN JOURNAL OF CLINICAL INVESTIGATION, Issue 2009N. J. Davie Abstract Pathological vascular remodelling is a key contributor to the symptomatology of pulmonary arterial hypertension (PAH), and reversing this process may offer the best hope for improving this debilitating condition. The vascular remodelling process is believed to be due to endothelial cell dysfunction and to involve altered production of endothelial cell-derived vasoactive mediators. The observation that circulating plasma levels of the vasoactive peptide endothelin (ET)-1 are raised in patients with PAH, and that ET-1 production is increased in the pulmonary tissue of affected individuals, makes it a particularly interesting target for a therapeutic intervention in PAH. Clinical trials with ET receptor antagonists (ETRAs) show that they provide symptomatic benefit in patients with PAH, thereby proving the clinical relevance of the ET system as a therapeutic target. In this paper, we review the role of ET-1 together with the available data on the roles of the specific ET receptors and ETRAs in PAH. In particular, we discuss the possible role of ET receptor selectivity in the vascular remodelling process in PAH and whether selective ETA or nonselective ETA/ETB blockade offers the greatest potential to improve symptoms and alter the clinical course of the disease. [source] How B cells shape the immune response against Mycobacterium tuberculosisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 3 2009Paul J. Maglione Abstract Extensive work illustrating the importance of cellular immune mechanisms for protection against Mycobacterium tuberculosis has largely relegated B-cell biology to an afterthought within the tuberculosis (TB) field. However, recent studies have illustrated that B lymphocytes, through a variety of interactions with the cellular immune response, play previously underappreciated roles in shaping host defense against non-viral intracellular pathogens, including M. tuberculosis. Work in our laboratory has recently shown that, by considering these lymphocytes more broadly within their variety of interactions with cellular immunity, B cells have a significant impact on the outcome of airborne challenge with M. tuberculosis as well as the resultant inflammatory response. In this review, we advocate for a revised view of TB immunology in which roles of cellular and humoral immunity are not mutually exclusive. In the context of our current understanding of host defense against non-viral intracellular infections, we review recent data supporting a more significant role of B cells during M. tuberculosis infection than previously thought. [source] How many mechanisms do regulatory T cells need?EUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2008Dario Vignali Dr. Abstract A plethora of new regulatory T cell (Treg) mechanisms have recently emerged. This raises two important questions. First, how many molecules or mechanisms are required for Treg to work? Second, how should we evaluate the contribution of any given Treg molecule/mechanism and how is this likely to relate (or not) to the phenotype seen in Scurfy/Foxp3-deficient mice? In this discussion piece, I will briefly outline our current understanding of the Treg arsenal and address these important questions. See accompanying commentary: http://dx.doi.org/10.1002/eji.200838143 [source] New vistas on macrophage differentiation and activationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 1 2007Alberto Mantovani Prof. Abstract Plasticity and heterogeneity are hallmarks of myelomonocytic differentiation and polarized activation. Evidence published in this issue of the European Journal of Immunology, together with other recent data, add new elements and perspectives to the current understanding of mononuclear phagocyte differentiation and activation and are discussed in this Commentary. See accompanying articles http://dx.doi.org/10.1002/eji.200636054 and http://dx.doi.org/10.1002/eji.200636788 [source] ADAM17 activity during human neutrophil activation and apoptosisEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 4 2006Bruce Walcheck Dr. Abstract Substrates of the metalloprotease ADAM17 (also known as TNF-, converting enzyme or TACE) undergo ectodomain shedding and include various inflammatory modulators. Though polymorphonuclear leukocytes contribute significantly to inflammation, direct analyses of ADAM17 on human neutrophils are very limited. In addition, the current understanding of the processes regulating ADAM17 activity primarily relate to its rapid activation. Therefore, to extend insights into the mechanisms of ADAM17 activity, we examined its surface expression and the shedding of its substrates during extended periods of neutrophil activation and apoptosis. Contrary to studies with immortalized hematopoietic cell lines, we report that surface expression of ADAM17 is maintained by human neutrophils activated with formyl peptides or by FcR/complement receptor-mediated phagocytosis. Interestingly, bacterial phagocytosis resulted in a significant increase in ADAM17 expression several hours after pathogen engulfment. We provide novel evidence that ADAM17 surface expression is also maintained during spontaneous and anti-Fas-induced neutrophil apoptosis. The well-validated ADAM17 substrates L-selectin and proTNF-, were shed efficiently by neutrophils under each of the conditions tested. Our data thus indicate prolonged ADAM17 expression during neutrophil effector functions. The implications of this may be a role by ADAM17 in both the induction and down-regulation of neutrophil activity. [source] | ||||||||||||||||||||||||||||||||||||||||