Epigenetic modifications are those reversible, mitotically heritable alterations in genomic expression that occur independent of changes in gene sequence. Epigenetic studies have the potential to improve our understanding of the etiology of mood and anxiety disorders and suicide by bridging the gap in knowledge between the exogenous environmental exposures and pathophysiology that produce common mood and anxiety disorders and suicide. We systematically reviewed the English-language peer-reviewed literature about epigenetic regulation in these disorders between 2001–2011, summarizing and synthesizing this literature with respect to directions for future work. Twenty-one articles met our inclusion criteria. Twelve studies were concerned with epigenetic changes among suicide completers; other studies considered epigenetic regulation in depression, post-traumatic stress disorder, and panic disorder. Several studies focused on epigenetic regulation of amine, glucocorticoid, and serotonin metabolism in the production of common mood and anxiety disorders and suicide. The literature is nascent and has yet to reach consensus about the roles of particular epigenetic modifications in the etiology of these outcomes. Future studies require larger sample sizes and measurements of environmental exposures antecedent to epigenetic modification. Further work is also needed to clarify the link between epigenetic modifications in the brain and peripheral tissues and to establish ‘gold standard’ epigenetic assays. Nearly 50% of adults in the United States have experienced a mood or anxiety disorder at some point in their lives. Mood and anxiety disorders are among the most debilitating diseases worldwide—the World Health Organization’s latest Global Burden of Disease report ranked depression among the top three most prevalent causes of disability globally, accounting for the highest single proportion of years lived with disability around the world ,2. PanicThe search for causes of common mood and anxiety disorders and suicide has spanned at least a century of research in a wide range of disciplines. However, a gap remains between studies focused on exogenous environmental determinants such as negative life events  or neighEpigenetic modifications are those reversible, mitotically heritable alterations in genomic expression that occur independent of changes in gene sequence . Rather Given the growing interest in behavioral epigenetics it appears to be the appropriate time to take stock, and to synthesize the peer-reviewed literature about epigenetic modification in the etiology of common mood and anxiety disorder and suicide. In reviewing the existing literature, we aimed to summarize the state of the science, identify methodological challenges, and offer potential solutions to address these challenges.st, 2001 and December 1st, 2011—we limited our review to the years following the sequencing of the human genome to reflect current thinking about the genetics of psychopathology. The literature reviewed here was identified via the MEDLINE and PSYCHINFO databases.We systematically reviewed the literature about epigenetic factors in the etiology of mood and anxiety disorders and suicide. We restricted our search to English-language, peer-reviewed articles. Our review encompassed the literature published between January 1Our original search yielded 1273 articles, 600 of which were judged to consider epigenetic factors in the etiology of mood and anxiety disorders and/or suicide after screening by title. Another 368 were discarded after screening by abstract because they did not consider epigenetic mechanisms or disease outcomes of interest. Of the remaining 232, articles were included in the review if they fulfilled the following criteria:· Included original data about a n > 1 sample of human subjects· Used DSM-III, DSM-IV, or ICD-10 criteria to classify participants as having common mood or anxiety disorders  OR used coroners’ reports to classify cause of death by self-inflicted injury· Objectively assessed epigenetic mechanisms relating to the etiology of mood and anxiety disorders or suicideAfter reading the complete manuscripts, 211 were excluded because they did not meet our criteria, above. This left 21 articles from the original search considered in this review. Reference lists from these articles were searched, and yielded no further articles which fulfilled the inclusion criteria, yielding a final total of 21 articles reviewed here. FigureBecause of the diversity of outcomes in which we were interested, the genetic pathways considered in the extant literature, and the methods used to both assess for epigenetic mechanisms and statistically analyze the findings, a meta-analysis of the results would not have been appropriate or feasible. For each of the 21 papers, we extracted the following information: the outcome of interest; sample population; proportion male; proportion White; number of cases and controls; loci considered; tissues sampled; laboratory techniques used; statistical analyses employed; and summary of the findings.Table All of the studies concerned with epigenetic factors in suicide assessed gene expression and methylation profiles in the post-mortem brains of suicide completers relative to non-suicide controls -25, althThere were twelve studies concerned with epigenetic mechanisms in the etiology of suicide -25. Thre1-acetyltransferase (SAT1) methylation was not associated with suicide. Similarly, there was no association between H3K27me3 methylation and suicide. A fourth study using post-mortem brain samples of 20 suicide cases and 20 non-suicide controls from the Geneva Institute for Forensic Medicine considered methylation of the spermine/spermidine N1-acetyltransferase (SSAT) gene promoter in the ventral prefrontal cortex in the etiology of suicide and found no association between methylation and suicide.Several studies considered epigenetic modification of genes involved in amine metabolism in the brain. Three studies using data from the Quebec Suicide Brain Bank and non-suicide controls from the same area considered the role of histone methylation at different locations in the etiology of suicide with conflicting results. The first found no association between H3K4me3 methylation at either spermine synthase (SMS) or spermine oxidase (SMOX) and suicide . In addiOne study was concerned with epigenetic modifications of genes involved in 5-HT metabolism. De Luca and colleagues studied both the post-mortem brains of suicide completers as well as peripheral blood methylation expression profiles of suicide attempters to assess the role of epigenetic modification of the 5-HT2A C102 in the etiology of suicide . CompariA promoter hypermethylation [A promoter [Poulter and colleagues used post-mortem brain samples from several brain regions from 10 suicide completers and 10 non-suicide controls in Budapest to assess the role of DNA methyltransferase (DNMT) expression and subsequent GABAhylation . They fopromoter .One study considered the role of epigenetic regulation of the neuron-specific glucocorticoid receptor (NR3C1) in suicide etiology among those with a history of childhood abuse . McGowanA final study considered the etiology of suicide among depressive patients. Klempan and colleagues assessed differences in methylation and expression of the oligodendrocyte-specific RNA binding protein (QKI) in suicide completers with a history of major depression relative to age-matched non-suicide controls . AlthougThere were five studies concerned with the role of epigenetic modification in the etiology of mood disorders—all five were concerned specifically with depression ,26-29. TA study by Alt and colleagues assessed the relationship between glucocorticoid receptor (GR) promoter methylation in several regions of the post-mortem brains of depressed patients relative to non-depressed controls from the Dutch Brain Bank matched on age, sex, brain weight, post-mortem delay, and pH of the cerebrospinal fluid . There wIn a study of a Japanese sample of depressed patients and non-depressed controls recruited from four academic medical centers, Fuchikami and colleagues assessed the relation between BDNF promoter methylation in white blood cells and depression . They foA final study considered “functional annotation clusters” (FACs) of epigenetic modifications in the whole blood of a community-based sample in Detroit, MI . The autThere were four studies that considered epigenetic mechanisms in the etiology of anxiety disorders ,30-32. TWith respect to PTSD, none of the three studies considered epigenetic modification of one specific gene pathway. Rather each considered non-specific sets of pathways. A study by Smith and colleagues of a cohort of African-American participants recruited at clinical waiting rooms in a low income context used linear mixed models adjusted for age, sex, and assay effects, found that increased methylation in white blood cells was associated with lifetime PTSD . MoreoveA fourth study was concerned with the role of epigenetic modification of the promoter as well as exon 9 of the neuroepithelial cell transforming (NET) gene promotor and exon 9 in the etiology of panic disorder . Using pWe systematically reviewed the peer-reviewed literature about the role of epigenetic modification in the etiology of common mood and anxiety disorders and suicide. Twenty-one papers were published between 2001, the publication of the human genome project, and 2011. The majority (12) of studies we found were concerned with evidence of epigenetic changes in the post-mortem brains of suicide completers, with other studies considering epigenetic factors in the etiology of depression, PTSD, and panic disorder. A plurality focused on epigenetic regulation of genes involved in amine, glucocorticoid, and serotonin metabolism in the production of common mood and anxiety disorders and suicide; studies also considered epigenetic modification of a diverse array of other genes.Given the small number of studies, drawing substantive conclusions about how epigenetic modifications in specific genes may be operating in the etiology of the diseases in question is not possible at this stage. Our review occasions a synthesis of methodological limitations of the extant literature and recommendations on how investigators may best approach this area in future studies.Five methodological limitations to this literature emerge from our review. The first is that studies in this area have suffered from small sample sizes, the consequences of which include lack of power and increased false discovery rates. Second, existing studies have been limited to assessing epigenetic modification in the post-mortem brain or the peripheral blood following disease diagnosis, and drawing inference from either tissue type is problematic. Third, studies have used different techniques to assess epigenetic modifications that may produce heterogeneous results. Fourth, few studies have assessed environmental antecedents to epigenetic modifications in extant studies. Fifth, there appears to be little consensus regarding genome-wide vs. candidate-gene approaches.The first methodological limitation to this literature is the use of small sample sizes in most studies, a ubiquitous problem in molecular epidemiology . Of the ^ “prior” indicates the proportion of tested hypotheses that are actually correct.In this equation, the false discovery rate (FDR) is inversely proportional to power (1-beta), such that low power also yields high FDR, driving up Type I error. Therefore, given the small sample sizes employed in the majority of studies we reviewed, it is likely that the findings suffer from high proportions of both type I and type II error.A second limitation is the use post-mortem brain or peripheral cell tissues for epigenetic analyses. Seven of the 21 studies we reviewed analyzed epigenetic modification in peripheral blood cells, and one study analyzed epigenetic modification in buccal mucosa. Although all human cells carry the full endowment of genetic material, cells modify gene expression to efficiently carry out their diverse functions as they specialize, silencing some genes while activating others in line with their physiologic responsibilities. Epigenetic modification is the physiologic process by which genes are silenced or primed for expression ,38. The A third limitation to the literature is that published studies used different laboratory techniques to measure the degree of epigenetic modification. With respect to DNA methylation alone, there are a number of gene-specific assays currently in use, including bisulfite reaction based DNA sequencing methods, which include bisulfite genomic sequencing PCR  and/or mFourth, studies in our review largely failed to assess the environmental exposures thought to produce epigenetic change to begin with. Only three out of 21 of the studies reviewed here included any assessment of a common environmental stressor with respect to epigenetic modifications and their relationship with common mood and anxiety disorders and suicide ,19,20. Tanywhere in the genome influencing risk for outcomes of interest. As candidate-gene approaches are more likely to yield negative overall findings, there is a high probability of publication bias, whereby the literature about candidate-gene epigenetic modification is likely to be highly enriched for positive findings [The fifth limitation is the lack of consensus regarding genome-wide vs. candidate-gene approaches in epigenetic studies. Three of the studies we reviewed used genome-wide approaches ,30,32, wfindings .The reader should be aware of several limitations when considering the findings of our systematic review. First, we limited our review to the published peer-reviewed literature. Therefore, it is plausible that our selection of studies may have been subject to a publication bias, affecting the veracity of our inferences. Second, we organized studies by outcome. This organizational scheme may have also, in part, shaped the inferences drawn here. However, because we limited our inferences largely to methodological critiques of the literature, it is unlikely that either limitation would have had a substantial influence on our interpretation of our findings. Third, our review was limited to only the English-language literature published in journals indexed in two databases. It is plausible that we may have missed literature about epigenetics in relation to common mood and anxiety disorders and suicide published in other languages or in journals that were not indexed in MEDLINE or PSYCHINFO. However, this is less likely, as a detailed search of the citations of included studies yielded no further studies for inclusion in the review.Research into the epigenetic mechanisms that may underlie common mood and anxiety disorders and suicide has the potential to unite the heretofore disparate bodies of work that have characterized the pathophysiology of these disorders and their population causes, respectively. However, at this nascent stage in the development of this literature, there are several methodological challenges, discussed above, that have yet to be addressed. With respect to these challenges moving forward, studies about the role of epigenetic regulation in the etiology of common mood and anxiety disorders can improve in the following ways.As sufficient power and small sizes have dogged extant studies in this area, future studies require larger sample sizes, maximizing power and minimizing the false discovery rate. Furthermore, systematic comparisons of assays used to assess epigenetic modifications are needed as is consensus around what constitute ‘gold standard’ laboratory techniques for assessing epigenetic modification. Another challenge to this literature is the validity of using epigenetic data from peripheral blood, epithelial tissue, or post-mortem brain specimens. However, given the obvious limitations to sampling brain tissue in representative populations of living subjects, sampling these tissues may, in the long-term, remain the best available option. Future work associating epigenetic modifications with changes in gene expression and correlating epigenetic modifications in peripheral tissues with brain function may offer one way to address these limitations. Moreover, work in neuroscience to characterize the relationship between real-time brain imaging studies and epigenetic modification in brain regions sampled among patients undergoing neurosurgery, when living-patient brain samples can be collected, could yield imaging markers of epigenetic regulation in the brain. These approaches represent a handful of the many lines of inquiry that could improve our capacity to assess epigenetic modification in the brain. Future studies in this area would also do well to measure epigenetic modification in relation to its environmental antecedents so as to better assess dominant hypotheses about the mediation of the relationship between environmental exposures and common mood and anxiety disorders and suicide by epigenetic modification.Lastly, both genome-wide and candidate gene approaches have their role in epigenetic analyses. Genome-wide approaches may be more appropriate for exploratory analyses . HoweverThe authors declare that they have no competing interests.AME extracted data from studies and drafted the manuscript. MRH carried out the literature search and edited the manuscript for intellectual content. SG edited the manuscript for intellectual content. KCK conceived the review, specified review inclusion and exclusion criteria, and edited the manuscript for intellectual content. All authors have read and approve the final version.


E. coli, a binding event in the periplasmic domain of the receptor dimer causes a shift in a single transmembrane helix of roughly 0.15 nm towards the cytoplasm. This small change is propagated through the ∼22 nm length of the receptor, causing downstream inhibition of the kinase CheA. This requires interactions within a trimer of receptor dimers. Additionally, the signal is amplified across a 53,000 nm2 array of chemoreceptor proteins, including ∼5,200 receptor trimers-of-dimers, at the cell pole. Despite a wealth of experimental data on the system, including high resolution structures of individual domains and extensive mutagenesis data, it remains uncertain how information is communicated across the receptor from the binding event to the downstream effectors. We present a molecular model of the entire Tsr dimer, and examine its behaviour using coarse-grained molecular dynamics and elastic network modelling. We observe a large bending in dimer models between the linker domain HAMP and coiled-coil domains, which is supported by experimental data. Models of the trimer of dimers, built from the dimer models, are more constrained and likely represent the signalling state. Simulations of the models in a 70 nm diameter vesicle with a biologically realistic lipid mixture reveal specific lipid interactions and oligomerisation of the trimer of dimers. The results indicate a mechanism whereby small motions of a single helix can be amplified through HAMP domain packing, to initiate large changes in the whole receptor structure.Bacterial chemoreceptors provide an important model for understanding signalling processes. In the serine receptor Tsr from  E. coli inner membrane. We show that in isolation the dimers undergo a bending movement around the central HAMP domain, whereas the trimer-of-dimers model does not. Comparison with published experimental data suggests that these bending motions are real, and that they occur in the trimer of dimers only in response to ligand binding. Drawing together these observations with studies showing that the signalling event involves small piston motions in the transmembrane helices suggests that the bending motion is frustrated in the unliganded trimer of dimers, and that ligand binding induces bending by repacking the HAMP interface.To understand cell signalling events requires a physical model of the structure and behaviour of the signalling proteins involved. The methyl-accepting chemoreceptor proteins direct bacterial movement towards food sources and away from toxins. Based on experimental data we have built structural models of the serine chemoreceptor (Tsr) as a dimer, which is incapable of activating the downstream kinase CheA, and as a trimer of dimers, which can activate CheA. We have performed molecular dynamics simulation to reveal the behaviour of these two forms in a planar lipid bilayer and in a 70 nm diameter lipid vesicle with a mixture of lipids mimicking the  E. coli  rotation of the motor causes the flagellar filaments to coalesce and the cell to move in a single direction (or “run”), whereas clockwise (CW) rotation causes the flagellum bundle to dissociate and the cell to reorient Transmembrane (TM) signalling plays a key role in cell biology. Signals can be conveyed across the membrane by subtle motions of single TM α-helices or TM helix dimers, and may result in substantial changes in protein structure and activity, and in turn lead to changes in cellular function and behaviour. One example where such signals are transmitted across a wide range of physical scales is the process of bacterial chemotaxis in E. coli . E. coliE.coli transmembrane chemoreceptors. These form stable homodimers which come together as trimers of dimers in a large receptor array at the cell poles. Serine binding to the periplasmic domain in Tsr causes small (∼0.15 nm) piston-like motions in the position of a single helix in the cytoplasmic membrane 2 receptor array The response to serine is mediated by the methyl-accepting chemoreceptor protein (MCP) Tsr. Tsr is one of four The small conformational change induced by binding must be transmitted to a highly sensitive downstream signalling domain and amplified to create a conformational signal which can be passed through the highly stable receptor complex. In particular, the role of a highly conserved HAMP domain in the receptor is the topic of intensive study. HAMP is a linker domain present in histidine kinases, adenyl cyclases, methyl-accepting proteins and phosphatases which is found in bacterial sensor and chemotaxis proteins and in eukaryotic histidine kinases. High resolution structures have highlighted the importance of packing and orientation in isolated HAMP domains and poly-HAMP domains E. coli inner membrane. CG-MD simulations have been used successfully to model a wide range of different phenomena relating to membrane proteins, including: transmembrane peptide anchoring, lipid-protein and lipid-DNA interactions Here we describe the structure and predicted dynamic properties of full-length homology models of Tsr dimers (representing the non-kinase activating form) and trimers-of-dimers (representing the kinase activating form) using coarse-grained molecular dynamics (CG-MD) simulations. We explore the behaviour of these large assemblies over microsecond time periods, both in a model lipid membrane bilayer (DPPC), and also in a ∼70 diameter nm vesicle containing a mixture of cardiolipin, phosphatidyl-glycerol and phosphatidyl-choline and thus mimicking the Archeoglobus fulgidusModels of the complete length, symmetric dimer of Tsr were built from the crystal structures of component domains where available , and for HAMP from the NMR structure (2ASX) of the homologous HAMP domain from We generated models of the dimers as described below. Briefly, models of pairs of domains connected by helices were generated and converted to their coarse grain representations. These were then simulated for 200 ns to allow the structure to equilibrate. The equilibrated structures were used as inputs alongside the high resolution structures to build the complete symmetric model of the dimer. The resulting structure was validated against a variety of experimental data, including the available high resolution structures from the PDB Four simulations each of 5 microsecond duration were performed for the isolated Tsr dimer structure in a phospholipid (DPPC) membrane see . In eachWe re-examined several different experimental studies containing structural data on the behaviour of isolated chemoreceptor dimers to determine whether this bending is realistic. In Tar R259  has been highlighted as a region which is sensitive to proteolysis and therefore proposed as a region of high flexibility Despite the significant extent of the bending observed the fold of the individual proteins is maintained. At the hinge point, however, the bending causes structural repacking in the HAMP domain. Specifically, the bending largely maintains the hydrophobic packing interface, but the AS2 helices (leading to the coiled-coil domain) undergo rotations and sliding throughout the simulation. Previous disulphide mapping studies on the related HAMP domain from Tar indicated that introduction of disulphide bonds into HAMP could lock the receptor into a kinase on/off state We next built a complete trimer-of-dimers model using snapshots taken from simulation of Tsr dimers (with a bending angle of ∼30°). Crystal contacts were used to model the trimer of dimers interface , as usedThe dynamics of the trimer-of-dimers assembly is distinct from the behaviour of the dimer in that trimer-of-dimers structure remains more stable and does not exhibit the pronounced bending that was observed for the dimer . Experimental preparations of Tsr in nanodiscs have shown that the complete trimer of dimers is required for kinase activation E. coli inner membrane lipid bilayer and consisted of a mixture of 10% cardiolipin, 18% DPPG and 72% DPPE. 30 dimers or 10 trimers-of-dimers were distributed evenly across the surface of the vesicle and the structures were free to interact without steering or restraints  were performed over at least 1 microsecond, in a 70 nm lipid vesicle. The lipid composition of the vesicle was intended to mimic that of the native straints ; Table 1R. sphaeroidesPreviously observed kinking behaviour of the Tsr dimers was replicated in the vesicle system, where the bending motions allowed individual dimers to form interactions with other dimers over the simulation. Over 1.5 microseconds some of these inter-dimer interactions  can be sE. coli inner membrane E. coli cell poles, and it is possible that this may alter the signalling behaviour by altering the packing of lipids against the protein surface.The mixture of lipids has been shown to be important for function of the Tsr trimer of dimers in nanodisc preparations. Cardiolipin is known to locate to the pole of the cell In this study we have built and simulated the dynamics of complete models of the bacterial receptor Tsr using coarse grained molecular dynamics, in different membrane environments. We have found that Tsr dimers in isolation undergo large bending motions around the region connecting the HAMP domain to the coiled coil domain, which is supported by experimental data and unlikely to represent a kinase activating structure . Models of the trimer of dimers state show the stabilising effects of the trimer assembly, and that the trimer does not undergo the same bending. This trimeric form resembles the observed cryoelectron data and likely represents the kinase activating form. The bending observed in the isolated dimer, in the context of the trimer-of-dimer can be expected to relate the observed cryoelectron density of the kinase active apo trimer-of-dimers to the ligand bound form, with observed “expanded” structure. EPR data on the structure and dynamics of HAMP domains in the related signal transducer NprHtrII showed that in the absence of light of the HAMP domain of the protein also adopted a “dynamic” state, where the packing of the domain was rearranged and mobility increased Overall, these motions suggest that the HAMP interface is sensitive to small motions and able to undergo changes in response to these motions to the complete protein. Signalling events in the periplasm have been proposed to cause a piston-like motion of TM2, based on a wide range of experimental and computational studies  available  and equilibrated domain pair structures . To build an initial approximation of the inter-domain regions we built models based on pairs of domains connected by continuous helices . These were modelled as helices as both PSIPRED and Jpred3 predictions predict continuous helicity in the missing regions These structures were converted to coarse grain models using standard techniques as described below, and simulated for 200 ns at 323 k in cuboid boxes with explicit CG water and counter-ions to neutralise the system. The missing regions were explicitly modelled as helices during the coarse grain process, enforcing expected secondary structure. Over the course of the receptor/TM domain pair simulation, the TM helices could be observed to assemble from a loose, splayed conformation into a tight bundle, without lipids trapped between the helices.The resulting trajectories from these simulations were visualised and representative structures from the last 100 ns identified through clustering using g_cluster . The middle structures of the dominant cluster identified in each simulation was converted back to atomistic models using the approach of Stansfeld et al The individual high resolution structure of the domains were each symmetrical  in their observed forms. Furthermore, the regions modelled in the domain pair simulations packed together tightly (excluding water/lipids where 4 helices were able to pack together), and becoming near symmetrical. Thus, in building the model of the complete Tsr dimer, symmetry was imposed on the complete dimer, and helicity was imposed in the connecting regions. 25 models were generated with Modeller To generate a trimer of dimers model of Tsr, snapshots from CG-MD simulations of the Tsr dimer, and the crystal contacts observed in PDB:1QU7. The resulting structure was initially simulated for 500 ns with harmonic restraints in the trimerisation region between individual dimers.CG-MD simulations were performed using procedures described previously using the standard MARTINI forcefield www.gromacs.org) Simulations were performed with Gromacs 4 (Gaussian and anisotropic network modelling was performed as described in A ∼70 nm vesicle was generated by self assembly from a loosely packed shell generated with using packmol


Digital hydrologic networks depicting surface-water pathways and their associated drainage catchments provide a key component to hydrologic analysis and modeling. Collectively, they form common spatial units that can be used to frame the descriptions of aquatic and watershed processes. In addition, they provide the ability to simulate and route the movement of water and associated constituents throughout the landscape. Digital hydrologic networks have evolved from derivatives of mapping products to detailed, interconnected, spatially referenced networks of water pathways, drainage areas, and stream and watershed characteristics. These properties are important because they enhance the ability to spatially evaluate factors that affect the sources and transport of water-quality constituents at various scales. SPAtially Referenced Regressions On Watershed attributes (SPARROW), a process-based/statistical model, relies on a digital hydrologic network in order to establish relations between quantities of monitored contaminant flux, contaminant sources, and the associated physical characteristics affecting contaminant transport. Digital hydrologic networks modified from the River Reach File (RF1) and National Hydrography Dataset (NHD) geospatial datasets provided frameworks for SPARROW in six regions of the conterminous United States. In addition, characteristics of the modified RF1 were used to update estimates of mean-annual streamflow. This produced more current flow estimates for use in SPARROW modeling. Processes controlling the supply, fate, and transport of chemical and organic constituents in terrestrial and aquatic systems occur throughout a watershed, from the headwater areas to the downstream receiving waters . Modified versions of the River Reach File (RF1)  and the Using geographic information systems (GIS), spatially referencing various natural and human-related watershed characteristics to a digital network allows for the rapid display and analysis of the geographic distributions. Relative quantities and the factors related to supply, fate, and constituent transport can be evaluated in geographic detail. Spatially referenced point locations along the network where direct measurements have been collected over time (instream monitoring) provide the means to discern multiple relationships between watershed characteristics, processes, and the observations. These relationships can then be evaluated in both space and in time. Watershed characteristics and process descriptions and associations can also be utilized in a variety of applications to further determine and assess the connections and the processes controlling fate and transport. These applications include flux-based water-quality transport models and methods to estimate stream characteristics like flow and velocity in ungaged locations.Many hydrologic models describe some aspect of the physical properties of the landscape. This includes the movement of mass in space and/or the change of mass in time. Models also can be designed to establish relations between water-quality monitoring, the supply of contaminants, and the natural attenuation processes that occur in transport across the landscape and within water pathways. Interpretations of model results can be useful at broad spatial and temporal scales to help address a variety of environmental-management decisions, including the design and tracking of contaminant reduction and protection strategies, monitoring practices and priorities, stream-health assessments, and regulatory requirements such as total maximum daily loads (TMDLs)  over a 100-year period until the early 1990s, when 1:24,000-scale mapping was completed . The NatLinking geographic information to digital representations of hydrologic features is a logical progression from maps to GIS and subsequent frameworks supporting hydrologic modeling . CartogrIn the early 1970s, the U.S. Environmental Protection Agency (USEPA) developed a hydrographic database of surface waters (RF1) for the conterminous United States . DesigneThe success of RF1 prompted the development of a more comprehensive hydrologic database. Reach File Version 3.0 (RF3) addressed the desire for more detailed hydrologic features at finer scales. Geographic representations of hydrologic features in RF3 were based on USGS 1:100,000 DLGs and provided a more detailed database for national, regional, and local reporting requirements such as those found in 305(b) sections of the Clean Water Act. Over 3,000,000 naturally flowing streams and constructed water bodies were represented nationally in RF3, a considerable increase from RF1  in unmonitored areas. The SPARROW methodology allows for separate statistical estimates of spatially referenced explanatory watershed characteristics that quantify the amounts of contaminant sources individually or collectively. These estimates are weighted by established relations between constituent mass and other geographically referenced physical factors affecting aquatic and terrestrial contaminant supply, fate, and transport. Because of spatial referencing and network connectivity, estimates of contaminant flux can be quantified at any location along the network. These quantities of contaminant flux for each reach can be portrayed in specialized maps at multiple spatial scales to better interpret and visualize the contributions from individual contaminant sources.A stream reach is the basic building block of the modeling framework . It is dEach reach also must be assigned a unique numerical sequence value (HYDSEQ) indicating its hydrologic order, from headwater to its termination point. Sequencing in a downstream direction based on reach-node topology gives an order to data processing that must be followed to route water from each stream segment to the next downstream segment throughout the network. This allows applications utilizing the network to accumulate mass referenced to the network in downstream order. Terminal reaches are defined as the last transport reach in which applications utilizing the networking capabilities terminate. SPARROW models compute the amount of flux prior to entering a fixed termination point such as a reservoir, international political boundary, or a terminal receiving body of water like an estuary or the ocean  because RF1 in this part of the country contained inconsistent variations in stream density and lacked spatial detail . In the A key network requirement for SPARROW modeling is the ability to connect pathways and associated characteristics hydrologically  response variables, explanatory variables, and predicted quantities of contaminant flux. Estimates of mean-annual streamflow and water velocity, reach length, mean-annual water travel time, reservoir surface area, and stream-reach type are examples of required characteristics referenced to the network and supplied to SPARROW models. Annual stream constituent-loading estimates serve as an independent response variable for SPARROW model calibration. Spatially referenced explanatory landscape, subsurface, and aquatic characteristics locate and identify quantities or surrogates of contaminant supply and the factors and processes associated with contaminant transport throughout the watershed. Geographically locating estimates of load (mass) on the reach network forms the basis to establish relations between constituent mass and the geographically referenced physical factors that may affect supply, fate, and transport  into two separate stream reaches, thereby creating a new reach upstream of the sampling site and maintaining the reach connectivity. In some cases, this approach may be desirable but impractical, and the monitoring site instead is associated with the closest downstream node of the reach .The spatial arrangement and the variable characteristics identified within a hydrologic network can be important when evaluating spatial relations related to water quality and hydrology at regional scales . GeospatGeospatial data sources representing explanatory properties vary in detail, spatial extent, and scale. Data layers from local sources may be more spatially detailed and have more specific information content than sources developed at a regional or national scale. Land-use data, for example, exist in various media, temporal and physical scales, and classification schemes for many local communities. However, compiling a land-use dataset for a regional area using locally derived data would be impractical because of these variations. Agricultural census data are another example of a dataset with spatial variations in information content. Some relevant agricultural data are collected at the farm-field level but, for privacy reasons, are distributed to the public only as county-level information. Simply apportioning the same county explanatory data at finer resolutions based on aerial distributions within the network does not necessarily improve the quality of that information; however, methods do exist that allocate general explanatory information to finer-scale land-use data within a county and catchment  and the surface area of the reservoir .SPARROW can be used to predict flux for each modeled reach, including unmonitored locations. These estimates are a function of the established linear relations between monitored contaminant flux and the quantities of constituent supply referenced to the network .The ability to describe, route, and simulate the transport of constituents throughout the landscape is a key component to hydrologic analysis and modeling . Flow chThe RF1-based spatial framework (MRB_E2RF1) is well suited for enhanced attribution of features like annual streamflow critical to SPARROW models. The streamflow estimates originally associated with RF1 reaches were computed in 1982 by W.E. Gates and Associates, under contract with the USEPA . The metIn the application described here, long-term average-annual streamflow estimates for each of the approximately 60,000 reaches were computed for the period 1971–2000. The method incorporates the calculation of runoff (flow per unit area) for hydrologic cataloging units on the basis of historical flow data collected at USGS streamgaging stations, estimation of flow delivered to individual stream reaches from their local catchments, and the use of the enhanced reach network to accumulate streamflow downstream to terminal locations. A local bias correction in the flow estimation then is applied by calculating the difference between estimated and measured flow at streamgaging stations and then interpolating the bias throughout the river network. The entire process is repeated for each individual water year during the period 1971–2000. A water year is defined as the period from October 1 to September 30, and the water-year designation  corresponds to the year of the ending date .2 with a median value of 3,000 km2.Estimates of hydrologic-unit runoff were generated by combining historical flow data collected at USGS streamgaging stations, the respective drainage-basin boundaries of the streamgaging stations, and the boundaries of the 2,110 hydrologic units. Streamgaging stations for the analysis were selected for each water year based on the availability of a complete daily flow dataset for the water year. Geospatial data representing drainage-basin divides from the location of each streamgaging station were delineated using the NHDPlus dataset and the accompanying digital-elevation-model-based flow-direction information . Basin b2 with a median value of 3,133 km2 (Hydrologic-unit subbasins and their associated eight-digit accounting numbers (HU-8s) are a widely used geographic framework for the conterminous United States. Each unit defines a geographic area representing part or all of a surface-drainage area or a combination of drainage areas. Subbasins subdivide larger accounting units (HU-6s), subregions (HU-4s) and regions (HU-2s) into smaller areas designated by the U.S. Water Resources Council and the USGS's National Water Data Network. Subbasins range in size from 24 to 22,808 km,133 km2 .Each geospatial basin boundary is then overlain on a geospatial dataset of HU-8s (the polygons outlined in bold black lines) to determine the area of intersection within the two datasets. For each overlapping area of HU-8s and drainage-basin boundaries, the fraction of the basin in the HU-8 and the fraction of the HU-8 in the basin are calculated. These fractions are then multiplied by each other to compute a weighting factor for each basin. The runoff values and associated weighting factors for all basins with any overlapping area with a HU-8 are combined, and a single weighted-average runoff value is computed for the HU-8 .The weighted-average runoff computations illustrated in −1] multiplied by area [L2] and can be expressed in common units of flow, such as cubic feet per second (ft3/s), by applying the appropriate units conversion. The catchment flow values were assigned to their respective stream reaches based on the unique identifier shared between the reaches and the associated catchments.The amount of flow delivered to each reach from its uniquely identified catchment was computed by intersecting the HU-8 runoff grid with MRB_E2RF1 catchments. Runoff values for each grid cell were summed based on the spatial intersection of the two datasets. The sum of grid-cell runoff values within each catchment has units of runoff [L·TFlow delivered to the stream network from the catchments was accumulated in the downstream direction by using topological information associated with the MRB_E2RF1 reach network . The topThe accuracy of the accumulated estimated flow was evaluated by comparing measured and estimated flow values at streamgaging stations. One way to visualize the accuracy is by tracking measured and estimated flow along main-stem river corridors. Two examples of main-stem corridors, the Hudson River and the Colorado River, are shown in The local bias in accumulated flows was quantified by calculating the difference between the estimated  at the upstream gaging station is multiplied by the drainage area of the ungaged segment (As) and then weighted by the ratio of the drainage area of the upstream station (Au) to the drainage area of the ungaged segment. The ratio Au/As approaches a value of 1 when the drainage areas of the upstream gaging station and ungaged segment are very similar, and Au/As approaches a value of 0 when the drainage area of the upstream gaging station is much less than that of the ungaged segment. This method reflects the assumption that the estimated bias measured at the upstream gaging station should be given significant weight at ungaged segments near the station, but the bias measured at the upstream gaging station should have less weight when applied to ungaged segments far downstream from the gaged site. It should be noted that the bias correction is not constrained to conserve mass.The bias correction method  is a heus was computed as: Bs is the bias at ungaged segment s, Bd is the bias at the downstream station, Ad is the drainage area of the downstream station, and As is the drainage area of ungaged segment s.If there was a downstream gaging station but no upstream station, then the bias at ungaged segment Bd/Ad) at the downstream gaging station is multiplied by the drainage area of the ungaged segment (As) and then weighted by the ratio of the drainage area of the ungaged segment to the drainage area of the downstream station (Ad). The ratio As/Ad approaches a value of 1 when the drainage areas of the downstream gaging station and ungaged segment are very similar, and As/Ad approaches a value of 0 when the drainage area of the downstream gaging station is much greater than that of the ungaged segment.s was computed as: Bs is the bias at ungaged segment s, Bu is the bias at the upstream gage, Bd is the bias at the downstream gage, Ad is the drainage area of the downstream gage, Au is the drainage area of the upstream gage, and As is the drainage area of ungaged segment s. If both upstream and downstream gaging stations are present, then the bias at ungaged segment Addition of the interpolated bias to the accumulated estimated flows throughout the river network generates bias-corrected flow estimates  was applied to all stream reaches for each individual water year from 1971 to 2000 and then the average was computed for the entire 30-year period.The ability to estimate mean-annual streamflow at ungaged reaches illustrates the benefits of using the river network as a component of the flow-estimation technique. The river network explicitly provides spatial connections between the ungaged reaches and the gaged streams. As represented by the bias-correction equations, knowledge of flow conditions upstream and downstream of ungaged reaches improves flow estimates compared to methods that do not incorporate network connectivity. These equations represent a type of spatial interpolation that is unique to river networks and cannot be approximated by simple Euclidean spatial methods. In a network-based interpolation, proximity between a streamgage and an ungaged reach is determined by upstream and downstream position within the network. In addition, similarity between the gaged and the ungaged reach is a function of the ratio of drainage areas, not linear distance.Regional-scale digital hydrologic networks used within the United States typically have been constructed from elevation points and hydrologic features collected by national mapping programs. The networks comprise hydrologically connected stream-reach segments depicting surface-water pathways and their associated drainage catchments. They can provide a consistent framework for descriptions and characterizations of aquatic and watershed processes controlling the supply, fate, and transport of constituents. Topological properties inherent to the networks provide the ability to simulate the movement of water and associated constituents. Collectively, these network characteristics are key components to hydrologic analysis and modeling. One such modeling application is SPARROW, a hybrid statistical approach that establishes relations between monitored contaminant flux, contaminant sources, aquatic transport processes, and the physical characteristics affecting transport. Explanatory properties associated with the network are evaluated to assess their significant contribution to supply and transport relative to the monitored flux.Nutrient SPARROW models presented in this issue have been developed to address water-quality issues throughout the conterminous United States. Supporting these regional models, are two separate digital hydrologic networks derived from the 1:500,000 River Reach File and 1:100,000 NHD . RF1 networks have been enhanced and modified to support various applications of SPARROW modeling, both regionally and nationally. The current national geospatial dataset contains topological and stream characteristics necessary to execute a SPARROW model. These characteristics reside in a single table and include reach topology, hydrologic sequencing, reach identification, mean-annual streamflow, velocity, travel time, reach length, reservoir surface area, and stream-reach type. Delineated drainage areas for each reach provide the ability to spatially link watershed characteristics to the stream network. Because of a simplistic structure, the RF1-based network is a viable choice for a hydrologic network supporting applications like SPARROW. It provides an adequate representation of hydrologic features and pathways at a regional or national scale.The need for accurate and updated stream characteristics prompted the use of the modified RF1 spatial framework to generate annual streamflow for each reach from 1971 to 2000. These updated flows were subsequently used in the regional SPARROW models presented in this issue. The equations used for the flow-estimation technique represent a type of spatial interpolation that is unique to river networks. Spatially explicit connections between ungaged and monitored locations provide knowledge of flow conditions upstream and downstream of ungaged reaches. In addition, similarities between the gaged reach and the ungaged reach are computed as a function of the ratio of associated drainage areas, not linear distance. This methodology was constructed such that it also could be used to improve the accuracy of the current estimated flows in more spatially detailed datasets like the NHDPlus.NHDPlus is an application-ready product based on a 2005 snapshot of three core national databases: NHD, NED, and WBD. Regionally, NHDPlus provides significant spatial detail  and a realistic representation of hydrologic pathways and numerous spatially referenced landscape and climatic characteristics. NHDPlus also contains appropriate topological and stream characteristics necessary to execute a SPARROW model. Additionally, an expanded capability of NHDPlus provides 30 m elevation-derived catchments and flow paths useful for more detailed spatial referencing and network generation. NHDPlus also benefits from a multi-agency coordination of NHD. Specific protocols for updating tools, features, and related information can potentially minimize any duplication of effort among stewards, incorporate corrections applied by SPARROW modelers, and provide a consistent dataset to the greater community.NHDPlus was constructed to meet a variety of needs and applications. Therefore, the complexity of NHDPlus resides in the components that also are dependent on changing and evolving databases like NHD, NED, and WBD. NHDPlus also contains a vast number of records in which relations between surface-water flow paths and other associated characteristics are not as simplistic as in RF1. Many external tables contain numerous attributes related by common fields to the spatial locations of hydrologic features. Standardized tools or scripts could automate and simplify procedures for establishing these relations and extracting the data for a specific use in models like SPARROW.As with many stream networks, the source information for mapping the hydrologic features of NHDPlus were based on cartographic interpretations. Mapping anomalies such as varying stream densities and isolated or unconnected reaches currently are being identified and corrected. One approach to improving inconsistencies in drainage density may be to remove streams in the smallest catchments.Hydrologic networks developed from elevation data may provide more flexibility for transport models like SPARROW. Elevation-based flow-path networks allow for the option of processing environmental information at a grid-cell level as opposed to a catchment, reach, or watershed level. This may provide a more precise way to aggregate source and transport characteristics and take advantage of additional monitoring and environmental explanatory information at finer scales. Like NHDPlus, the flow-path networks can be improved using drainage-enforcement techniques and the existing vector-based hydrography. NHDPlus also provides the necessary features that can be used to construct and evaluate a cell-based network supporting SPARROW modeling. In addition, detailed elevation data are becoming more readily available for larger areas. It also is feasible to assemble networks at various adjustable scales based on streamflows estimated by the techniques described in this article.


The worldwide increase in obesity is becoming a major health concern. General practitioners (GPs) play a central role in managing obesity. We aimed to examine Swiss GPs self-reported practice in diagnosis and treatment of obesity with a special focus on the performance of waist measurement.A structured self-reported questionnaire was mailed to 323 GPs recruited from four urban physician networks in Switzerland. Measures included professional experience, type of practice, obesity-related continuing medical education (CME) and practice in dealing with obesity such as waist measurement. We assessed the association between the performance of waist measurement and obesity-related CME by multivariate ordered logistic regression controlling for GP characteristics as potential confounders.A total of 187 GPs responded to the questionnaire. More than half of the GPs felt confident in managing obesity. The majority of the GPs (73%) spent less than 4 days in the last 5 years on obesity-related CME. More than half of GPs gave advice to reduce energy intakes (64%), intakes of high caloric and alcoholic drinks (56%) and to increase the physical activity (78%). Half of the GPs seldom performed waist measurement and documentation. The frequency of obesity-related CME was independently associated with the performance of waist measurement when controlled for GPs' characteristics by multivariate ordered logistic regression.The majority of GPs followed guideline recommendations promoting physical activity and dietary counselling. We observed a gap between the increasing evidence for waist circumference assessment as an important measure in obesity management and actual clinical practice. Our data indicated that specific obesity-related CME might help to reduce this gap. Obesity is a major health problem associated with increasing risk of diabetes mellitus, hypertension, heart disease, cancer, decreased life expectancy  and subsWeight problems were generally determined by body mass index (BMI), but waist circumference could also be a very useful and important indicator to identify those who are at risk and should seek weight management ,8. CompaThe high prevalence of overweight and obesity results in an urgent need for improved obesity-related assessment, treatment and management. General practitioners (GPs) have an important role in preventing and diagnosing weight problems ,11. ObesThe purpose of the present study was to examine GPs' practice in diagnosis and treatment of obesity with a special focus on obesity-related continuous medical education (CME) on the performance of waist measurement. CME is a widely used form of a postgradual learning event assuming a relationship between improved physician knowledge and clinical performance. Furthermore in many countries CMEs provide credits and are part of quality assurance programs for physicians to continue clinical practice.The present study is part of an intervention project titled "Management of Obesity and Cardiovascular Risk Factors in Urban Swiss General Practitioners Networks" which aimed to improve GPs' approach in diagnosis and treatment of obesity by a multifaceted intervention program. The program included a baseline assessment, followed by a one-year intervention and a follow-up assessment after the intervention. The intervention was offered to the members of one urban GP network. The members of three other urban networks served as controls. However, the present study reported only the results from the baseline assessment from all four networks focusing on obesity management. All GPs from four urban networks in the German speaking part of Switzerland (168 from the intervention group and 155 from the control group) were eligible to participate.A self-administered structured questionnaire including 73 questions was developed to assess GPs attitudes, practice, and knowledge as well as management in obesity and cardiovascular risk factors. The items in the questionnaire related to management and treatment are derived from guideline recommendations on obesity . The oriThe baseline questionnaires were sent to 323 GPs in March 2006: First, an invitation letter with the questionnaire was sent; second, a reminder postcard was sent two weeks later; finally, a second copy of the questionnaire and a reminding letter was sent to the non-responders another two weeks later.Descriptive analysis was performed to describe characteristics of GPs as well as their practice and treatment approaches for obesity. Categorical and continuous variables are presented as frequencies and means (SD). The variable of primary interest was the self-reported frequency of GP's performance of waist measurement consisting of three ordered categories . We assessed the crude association between waist measurement performance and obesity-related CME by using univariate ordered logistic regression.The odds ratios can be interpreted as a comparison of the chances of the outcome being equal or higher than a specific category as a ratio of the chances of being lower .2) and number of days attending obesity related CME in the last five years . The validity of the final model was tested by applying the proportional odds test  [To further investigate the association between waist measurement performance and obesity-related CME we controlled for GP characteristics as potential confounders by applying multivariate ordered logistic regression modelling. The final model included the following variables, irrespective of a cut-off score for a p-value related to an univariate analysis: sex, age (categorized as younger GPs " < 55 years" vs. older GPs "≥ 55 years"), professional experience (in years), work load (full-time vs. part-time), work setting , number of patients a week , feeling more confident in handling cardiovascular risk factors/obesity due to the membership in networks , estimated proportion of obese patients in the practice (percentage of patients with a BMI > 30 kg/mumption) .Statistical analysis was performed with STATA 10.0 (stata corp.).2) and about 30% (± 26.5) of these obese patients required special treatment according to the assumption of the GPs. More than half of the GPs felt confident in managing cardiovascular disease and/or obesity due to their membership in a physician network. In the past 5 years, most of the GPs (about 74%) attended less than four days of obesity-related CME.A total of 187 GPs responded to the questionnaire (response rate: 57.8%). The characteristics of the participating GPs are shown in Table Table Table 2 of the final model, a measure of the predictive efficiency, was 8.7%. Checking the final model did not provide evidence that the parallel regression assumption has been violated.Results of the regression analysis are displayed in Table The present study examined GPs' characteristics and self-reported practice in obesity management based on a cross-sectional study of 187 GPs in Switzerland. Slightly more than half of the GPs reported that they felt confident in managing obesity. These results are consistent with previous studies which have also found that primary care physicians have confidence in dealing with health consequences of obesity and overweight ,22.Recent literature showed that the waist circumference is an important determinant of the cardiovascular risk ,9. Due tOur study is the first study in Switzerland to evaluate the specific behavioural strategies that GPs advised their obese patients for weight control. Consistent with previous studies  and guidMoreover, our study revealed that most of the GPs recommended various dietary strategies such as reducing energy intake, lipid intake, consumption of alcoholic and high caloric drinks, and carbohydrate and proteins which has also been observed in an Israeli survey where 81% of the family physicians gave always or often advice to decrease total daily calories . Only a The main limitation of our results should be acknowledged. Our data reflect self reported behaviours, which can differ from daily practice. Regarding the main result, that CMEs have substantial influence on the reported behaviour, details about attended CMEs were not asked for. Furthermore, we do not have data on non-respondents. However, the participation rate of 57.8% exceeded the participation rate that can be expected from general practice postal surveys thus limiting the risk of a selection bias .One of the strengths of our survey is that the survey included a large number of GPs who are representative to the general Swiss GP population with regard to age, gender and work load according to the annual statistics of the Swiss Medical Association. A main characteristic of our study population is the membership in medical networks. The number of networks, especially in urban areas of Switzerland, steadily increased during recent years reaching up to 48.1% in the year 2010, thus making our study sample comparable to the increasing proportion of GPs joining a network in Switzerland. Furthermore, we confirmed that obesity is a prevalent problem in primary care and obesity related CME has the potential to improve GPs behaviour in obesity management thus our study provides further evidence of the important role of GPs to control for the "obesity epidemic". However, randomised studies that focus on prespecified obesity related CME interventions together with patient related clinical outcomes are needed to further optimize obesity management in clinical practice.The majority of GPs followed guideline recommendations promoting physical activity and dietary counselling. We observed a gap between the increasing evidence for waist circumference assessment as an important measure in obesity management and actual clinical practice. Most GPs followed less than 4 days of obesity-related CME during the last 5 years, while 4 or more days of CME did positively affect guideline adherence. Although there remain many factors affecting physician guideline adherence our data indicated that specific obesity-related CME might help to reduce this gap.The authors declare that they have no competing interests.MZ, TR, MMK and UZ contributed to the design of the study. CAH and OS carried out the statistical analysis. CAH and MMK prepared and edited the manuscript. All authors critically reviewed it and contributed to the final manuscript. All authors have seen and approved the final version of the manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2296/12/140/prepub


We evaluated the action of vasoactive drugs on baroreceptor regulation and the interaction of this in regulation of heart rate variability (HRV) in patients with septic shock.A prospective observational study of patients with severe sepsis or septic shock. Collected data were analyzed retrospectively, separating patients according to their clinical evolution: survival or death. We monitored troponin I, vasoactive drug dose, HRV and blood pressure variability.r = 0.77), while for norepinephine the correlation was poor (r = 0.53). The use of dobutamine showed a negative correlation with the low-frequency alpha index (index that assesses the integration of baroreceptor); on the other hand, norepinephine showed a positive correlation. See Table The study included 31 patients, of whom 14 died. Increased troponin levels were related to an increased risk of mortality. The alpha index of HRV low frequency and high frequency indicates that the interaction of baroreceptor in the regulation of heart rate variability with changes in blood pressure had a significant reduction in patients with septic shock and death. The use of dobutamine in patients with septic shock correlates well with troponin levels (Patients with septic shock have impaired baroreceptor function, and this is correlated with progression to death. Dobutamine is related to higher levels of cardiac damage and higher doses of dobutamine interfere with the responsiveness of the baroreceptor. Moreover, norepinephine has a positive effect on the integration of baroreceptor.


To take full advantage of NIRF materials in the biological and biomedical field, one of the key issues is to develop intense and biocompatible NIRF probes. In this review, a number of NIRF materials are discussed including traditional NIRF dye molecules, newly developed NIRF quantum dots and single-walled carbon nanotubes, as well as rare earth metal compounds. The use of some NIRF materials in various nanostructures is illustrated. The enhancement of NIRF using metal nanostructures is covered as well. The fluorescence mechanism and bioapplications of each type of the NIRF materials are discussed in details.Near-infrared fluorescent (NIRF) materials are promising labeling reagents for sensitive determination and imaging of biological targets. In the near-infrared region biological samples have low background fluorescence signals, providing high signal to noise ratio. Meanwhile, near-infrared radiation can penetrate into sample matrices deeply due to low light scattering. Thus,  The micet al. developed a ligand-modified NIRF dye functionalized LDL nanoparticle. The LDL nanoparticles enabled the first in vivo validation of the LDL rerouting principle. This was also the first in vivo application of the bio-nanocarrier for enhanced optical imaging of cancer cells in living animals.Besides the inorganic and polymer nanoparticles, some biomolecules are suitable nanocarriers for delivering of NIRF materials to targets. One example is the lipoprotein nanoparticles  31]. Th. Th31]. 7.etc.The high signal intensities, low detection limits, and fast response time are critical for sensitive determinations of trace amounts of biological targets. Thus, the high fluorescence intensity is desirable for all label reagents. However, the signal intensity of NIRF materials is intrinsic and limited by its maximum value. To raise the limit of their intrinsic intensities, signal amplification is required. Noble metal nanostructures  can enhance the fluorescence intensities of NIRF molecules which exist in their electromagnetic field. This phenomenon is called surface plasmon resonance enhancement. Based on the radiation mechanism of photoactive material, the surface enhancement can be further divided into surface/metal-enhanced fluorescence  and surf7.1The fluorescence enhancement of metals on dye molecules is determined by metal nanostructures. In nanodimension, the collective oscillations of metallic free electrons are limited by the nanostructure boundaries, and thus form the surface plasmon waves along the boundaries. The surface plasmon wave resonates with the incident wave at an optimal condition, which results in the greatest absorption of the incident light. The oscillation wave affects the nearby fluorophores in several aspects.Q) are changed based on the First of all, on the surface of metal nanostructure, the occurrence of surface plasmon resonance leads to a strongly enhanced absorption of the incident light. When the surface plasmon resonance band of metal nanostructure overlaps with the excitation of the fluorophores, the energy is transferred from the metal to the fluorophore so that the possibility of excitation of the dye molecule is increased. Thus, more ground state electrons of dye molecules can be transferred to the excited state and produce a higher fluorescence signal. Secondly, the metal nanostructure can change the radiative deactivation rate (Γ) of the fluorophores. Furthermore, the fluorescence lifetime (τ) and the quantum yield  by 20-fold [et al. [A number of metallic nanostructures have been developed as the enhancement substrates for higher intensity of NIRF dyes, such as the silver island films , 85, sil 20-fold . The enh [et al.  used theDifferent types of NIRF materials have been developed. In general, NIRF dye molecules are traditional fluorescent labeling reagents in bioimaging and bioanalysis. The emerging nanomaterials provide NIRF a promising new direction. QDs and SWNTs have demonstrated great potential as photostable and highly intensive NIRF tags for the determination of biological targets. Meanwhile, doping a large number of NIRF molecules into a nanomatrix to produce an intense fluorescence nanoprobe is attractive since it can fully use the developed NIRF dye molecules to generate a wide variety of NIRF nanomaterials. To further improve the fluorescence intensity, metallic nanostructures are combined with NIRF materials for sensitive determinations of trace amounts of targets. Each type of NIR material brings its own strengths and weaknesses to the table. Pulling from the strengths of each, novel and highly sensitive NIRF probes can be developed. Two major advantages in NIR region, low background signal and deep penetration of radiation, providing NIRF probes broad applications in the biological and biomedical field.


The calcifying epithelial odontogenic tumor (CEOT) is a rare benign epithelial odontogenic neoplasm of slow growth that is locally aggressive and tends to invade bone and adjacent soft tissue. Here is reported the case of a 21-year-old female patient with a CEOT in the left mandibular posterior region. The computerized tomography in coronal plane revealed a hypodense lesion in the posterior region of the left mandibular body with hyperdense areas inside and was associated with element 37. An incisional biopsy of the lesion was performed and the histopathological analysis revealed the presence of layers of epithelial odontogenic cells that formed prominent intercellular bridges. A large quantity of extracellular, eosinophilic, and amyloid-like material and an occasional formation of concentric calcifications (Liesegang rings) were also found. The histopathological diagnosis was a Pindborg tumor. Resection of the tumor with a safety margin was performed and after 6 months of follow-up there has been no sign of recurrence of the lesion. The calcifying epithelial odontogenic tumor (CEOT) or Pindborg tumor is a rare benign epithelial odontogenic neoplasm , 2, withA 21-year-old black female patient sought treatment at the Oral and Maxillofacial Trauma Surgery Unit, with swelling in the mandibular left posterior region. While performing the intraoral physical exam an asymptomatic hardened exophytic nodule was found in region 37 .The patient reported a clinical evolution of only five months of the lesion. A radiographic exam revealed a diffuse radiolucent, unilocular lesion, associated with region 37, yet including the distal root of region 36 up to the crown of region 38 . Using aAn incisional biopsy ensued and the specimen was sent to the Laboratory of Oral Pathology. The histopathological analysis revealed layers of odontogenic epithelial cells that formed prominent intercellular bridges. Areas of extracellular, eosinophilic, and amyloid-like material with an occasional formation of concentric calcifications (Liesegang rings) were also present . Based oSurgical resection of the tumor was performed, including a marginal portion of apparently healthy bone, while attaching a 2.4 mm reconstruction plate of titanium, in search of the patient's rehabilitation. After 6 months of follow-up there has been no sign of recurrence of the lesion.CEOT is an uncommon lesion which generally affects the posterior maxillary region. A frequent radiographic finding in these tumors has been the presence of calcifying structures of varying sizes inside the lesions. Besides this, the cases reported in the literature have mostly been painless, of a slow evolution, and in an intraosseous area –9. SuppoThe histological criteria of the Pindborg tumor are layers of polyhedral epithelial cells with well-defined borders that oftentimes show prominent intercellular bridges. Figures of mitosis are rarely seen. In the layer of epithelial cells, circles, full of a homogenous amyloid-like substance, were observed. Some of those cells were also filled with a calcifying matter in the form of Liesegang rings, which are pathognomonic of this tumor –5. The hGenerally its treatment is undergone beginning with the surgical excision of the tumor. As the lesion was not encapsulated, the majority of authors agree that resection should include a safety margin of bone that is considered clinically and radiographically healthy , 10. The


The aims of this study were to identify that the differences in the natural history of patients with symptomatic and asymptomatic carotid stenosis may be reflected in differences in the expression of procoagulant protein factors.Carotid artery plaques were obtained from 33 symptomatic and 4 asymptomatic patients with internal carotid artery stenosis of greater than 70%. These plaques were stained with monoclonal antibody against human tissue factor. Areas of staining for the cap and core were analysed using the analySIS computer programme.There were 37 patients, of whom 27 were male with a mean age 69.3 years and a range of 53 to 83 years. Statistical analysis using non-parametric tests revealed a significant increase in the area of positive staining for tissue factor in plaques taken from symptomatic patients when compared to those who were asymptomatic (P = 0001). Within the symptomatic patients group there was significantly increased tissue factor in the plaque core of those who were the most recently symptomatic (P = 0.003).The unstable carotid artery plaque is associated with significantly increased tissue factor expression in the cap and core. Plaques from the most recently symptomatic patients have significantly more tissue factor in the core and this may represent part of the mechanism responsible for plaque destabilisation. More research is needed in this important area.Tissue Factor; Carotid stenosis; Stroke; Plaque stability Stroke is the third commonest cause of death in the UK after coronary disease and cancer, and the principal cause of neurological disability . The annThe commonest cause of ischaemic stroke is thromboembolism of the internal carotid artery (ICA). Stenoses develop at the origin of the ICA because this is a complex region with haemodynamic phenomena compromising low shear stress, flow stasis and flow separation that predispose to atherosclerotic plaque formation. Should the plaque undergo acute change , the inner core of thrombogenic subendothelial collagen is exposed and this predisposes towards the formation of thrombus and the onset of symptoms .The carotid artery plaque is a dynamic structure. It may be stable and unlikely to produce symptomatic embolization and carotid occlusion or conversely, while not necessarily being any more stenotic, unstable and at high risk of producing symptomatic embolization or carotid occlusion .The majority of strokes are due to embolization from an atherosclerotic plaque or acute occlusion of the carotid artery and propagation of thrombus distally , howeverRisk factors for an ischaemic stroke include: sex, increasing age, smoking, hypertension, ischaemic heart disease, cardio-embolic source, peripheral vascular disease and diabetes . PresentAngiographic plaque surface morphology is used along with the degree of carotid stenosis to identify patients most likely to benefit from CEA and other preventive treatment . MRI angPrevious histological examinations have demonstrated subtle differences in the characteristics of atherosclerotic plaque removed from symptomatic patients. In symptomatic patients inflammation is more common, with greater number of macrophages and T cells detected in the cap of the symptomatic plaque . The necSmooth muscle cells lay down collagen, the principal connective tissue component of the fibrous cap. Collagen breakdown is dependant on the balance between proteolytic enzymes; matrix metallaproteinases (MMPs) and their inhibitors; tissue inhibitors of metalloproteinases (TIMPs). High levels of MMPs have been demonstrated at the site of the inflammatory infiltrate in the fibrous cap , smooth T-cells secrete CD-40 and interleukin-1 (IL-1), which activate macrophages which in turn stimulate the apoptotic activity of MMPs resulting in collagen degradation .On plaque rupture, exposure of the necrotic core to circulation promotes thrombosis. This appears to be an important mechanism of plaque progression, in addition to embolization. Increased expression of tissue factor, the most important stimulant of the extrinsic clotting cascade, has been demonstrated in plaques from patients with unstable angina or myocardial infarction . In an aTF is a 47-kD membrane bound, low weight molecular glyco-protein essential for the activation of the extrinsic coagulation pathway. TF receptor is a member of the class 2 cytokine receptor super-family. Growth factors and cytokines present in vascular smooth muscle cells and macrophages regulate the TF expression .TF complexes with factors VII and VIIa, permitting enzymatic activation of factors X and IX, the substrates for factor VIIa , and ultThe study included 37 surgical in-patients enlisted to undergo CEA for high-grade ICA stenosis . The study was approved by the local ethics review committee and performed in accordance with institutional guidelines. Informed consent was obtained from all patients. Baseline characteristics of the study population are provided in After longitudinal arteriotomy, the carotid atherosclerotic plaque was excised en bloc (routine endarterectomy), fixed immediately in buffered formalin, decalcified, and transversely sectioned at 5-mm intervals . Each 5-Absence of tissue factor antibody was regarded as a negative control, while a positive control was the presence of tissue factor antibody in a human colon cancer tissue. Mayers hematoxilyn was used to counter-stain all the sections to enable the histopathologist to review the slides.The analySISTM computer program was used to calculate the total area of positive TF staining within the cap and core of each specimen.Paired sample T-tests were not used to analyse the data, as it was not normally distributed . The non-parametric Mann-Whitney U test was used to investigate the relationship between the extent of TF expression (median TF+ section area in the cap and core of each plaque) and the occurrence of ischaemic symptoms. Kruskal-Wallis non-parametric test was used to study the relationship between TF expression (median TF+ section area in the cap and core of each plaque) and the time since symptoms. P values of < 0.05 were considered indicative of statistically significant findings. Measurement errors were calculated to account for the natural variation of the measurement process using the repeatability method ; values TF expression was found in all plaques, however there was a significant difference in the area of positive staining in plaques from symptomatic  and asymThe patients were then divided into groups according to the length of time between the last acute event and the CEA. Using the Kruskal-Wallis non-parametric test ; the expIn this study we have shown that in the most recently symptomatic carotid artery plaque there is an increased expression of TF when compared to the asymptomatic carotid artery plaque. Most TF immuno-reactivity was localised diffusely in the acellular necrotic core and in regions within the atheromas fibrous cap. Our data therefore strongly suggest that TF induction at various regions of the plaque may play an important role in the destabilisation of high-grade ICA stenosis.The mechanism responsible for thrombus formation associated with ruptured atherosclerotic plaques is not well understood. One widely held view is that rupture or fissuring of an atherosclerotic plaque results in exposure of collagen and other extracellular proteins to blood-borne platelets, which adhere to these elements via specific receptors and become activated . ActivatExposure of TF activity to coagulation factors may either occur directly at the intimal surface or may result from plaque rupture leading to the release of macrophage-bound or extracellular material from deeper parts of the plaque to the blood stream . The rupTF pathway inhibitor (TFPI) is found in vascular endothelium and smooth muscle cells as well as in platelets, blood monocytes, and macrophages , 35. It Evidence also suggests that TF may have a variety of other actions in addition to initiating thrombin formation. For example, TF: VIIa induces the activation of mitogen-activated protein kinase (MAP-Kinase) in a baby hamster kidney  and evokHuman atherosclerotic plaque tissue from CEA specimens express TF messenger-RNA and protein in a few intimal smooth muscle cells, as well as in a few macrophage-like cells adjacent to cholesterol clefts . Wilcox A potential limitation of our study arises from the fact that the sensitive immuno-histochemical staining procedure used for the detection of TF antigen does not allow direct conclusions with respect to the actual presence of TF bioactivity. However in a comparative study, Jander et al  used a s


Background. H-Y antigen incompatibility adversely impacts bone marrow transplants however, the relevance of these antigens in kidney transplantation is uncertain. Three previous retrospective studies of kidney transplant databases have produced conflicting results. Methods. This study analyzed the Organ Procurement and Transplantation Network database between 1997 and 2009 using male deceased donor kidney transplant pairs in which the recipient genders were discordant. Death censored graft survival at six months, five, and ten years, treated acute rejection at six months and one year, and rates of graft failure by cause were the primary endpoints analyzed. Results. Death censored graft survival at six months was significantly worse for female recipients. Analysis of the causes of graft failure at six months revealed that the difference in death censored graft survival was due primarily to nonimmunologic graft failures. The adjusted and unadjusted death censored graft survivals at five and ten years were similar between the two genders as were the rates of immunologic graft failure. No difference in the rates of treated acute rejection at six months and one year was seen between the two genders. Conclusions. Male donor to female recipient discordance had no discernable effect on immunologically mediated kidney graft outcomes in the era of modern immunosuppression. Identifying candidate minor histocompatibility antigens that impact outcomes after transplantation is difficult, and antigens that have been identified often have disparate effects depending on the organ or tissue transplanted. One minor histocompatibility antigen system that has been identified is the H-Y antigen system. The H-Y antigen system is produced by a series of genes found on the Y chromosome of males which produce proteins with distinct amino acid sequences from their X chromosome homologs and have significant tissue expression. Seven genes have been identified on the Y chromosome that posses these characteristics, and these antigens constitute the H-Y antigen system –4. OrganThe evidence for an effect of the H-Y antigen system in renal transplantation is less certain. The expression of these antigens on the surface of human kidney tissue is not well studied, so it is not clear if target H-Y alloantigens are expressed on kidney tissue. Antibody formation to H-Y antigens has been demonstrated, and in one small study female recipients of male kidneys who had detectable antibodies to H-Y antigens had a higher rate of acute rejection . RegistrSince donor quality is an important factor determining both short- and long-term outcomes in kidney transplantation, and the covariates used in modeling do not always capture all the differences, a paired cohort analysis of the OPTN database was undertaken in order to better analyze the impact of the donor recipient gender discordance on kidney transplant outcomes. Because death censored graft failure as an endpoint includes graft failures due to both immunologic and nonimmunologic causes, this paired study includes a more detailed analysis of the causes of graft failure and also an analysis of rejection rates reported to the registry. The primary graft outcomes analyzed were death censored graft survival at six months, five years, and ten years, treated acute rejection rate at six months and one year, and rates of graft failure at six months and from six months onward by putative etiology coded in the database. All male deceased donor kidneys from January 1, 1997 to November 27, 2009 in whom the recipient of each pair of kidneys was discordant for recipient gender, were selected from the OPTN database . Only reThe etiology of graft failure was determined from two data fields. One was the numerically coded cause of graft failure which included the following categories: hyperacute rejection, acute rejection, primary nonfunction, thrombosis, infection, surgical complication, urologic complication, recurrent disease, chronic rejection, or other. The second field used was a write-in field. For those graft failures coded as other, the write-in field was queried, and based on the documentation two additional causes were included: noncompliance and polyoma-virus-associated nephropathy. Write-in causes of graft failure not included in the list were coded as other. Also, if the query matched one of the numerically coded groups, the cause of graft loss was changed to that category. Graft losses without coding in either field were considered unknown. Recipients who died during followup and whose graft survival time was equal to their patient survival time were classified as death with graft function.Cox proportional hazard ratio survival analysis was carried out to determine the independent association of graft failure with donor recipient gender match . The following covariates were included in the model : recipient age, race/ethnicity , and body mass index (BMI), donor: recipient cytomegalovirus (CMV) serologic status  delayed graft function (DGF) , duration of dialysis prior to transplant, history of previous transplant, cold ischemia time, human leukocyte antigen mismatch, type of induction , maintenance immunosuppression at discharge, and panel reactive antibodies (PRA). Statistical significance for categorical variables was determined using the Pearson's chi-squared test and Fisher's exact test. ANOVA testing was used to determine statistical significance between scalar variables. Log rank testing was performed to determine statistical significance for Kaplan Meier survival analysis. Cox analysis included correlation due to the match pairs using the robust sandwich estimate of the covariance matrix specifying the linked recipient-donor pairs . A probaBetween January 1, 1997 and November 27, 2009, 12,479 male donors were identified in which both kidneys were transplanted as single kidney transplants in two recipients who were discordant for gender. The characteristics of the pairs are shown in P = 0.013). The survival curves show that the decrement in survival occurs in the first 30 days. The slopes of the curves after 30 days are nearly identical. Adjusting for the differences in the two populations, female recipients of male kidney had a statistically significant worse outcome when compared to their paired male recipient (Hazard Ratio 1.28 95% C.I. 1.12–1.46). This analysis suggests that the male donor to female recipient gender discordance does not have a significant impact on immunologic graft outcomes in the current era of immunosuppression. Our analysis is consistent with the finding from the previous analysis of the OPTN database by Kim and Gill that short-term graft outcomes were worse among female recipients of male kidneys when compared to male recipients while the long-term graft outcomes were not. Our analysis goes further to show that the difference in short-term outcomes occurs very early after transplant and is driven not by immunologically mediated graft failures but by a higher rate of graft thrombosis and graft failure due to other nonimmunologic causes. Similarly, our analysis did not show a difference in the rates in early acute rejection or late graft failures due to acute or chronic rejection consistent with the conclusion that for the vast majority of female recipients of male kidneys receiving modern immunosuppression the H-Y antigen incompatibility did not increase the risk of rejection or graft failure. The strength of this study is that it better controls for donor quality and assessed not only death censored graft survival but also the rates of rejection and graft failure by cause. The study has a number of caveats regarding the conclusions. First, the study is limited by the accuracy of the registry data regarding the coding of the cause of graft failure and episodes of rejection. Over 95% of case did have a specified code for cause of graft failure, and the number of cases coded as unknown was similar between the two groups. Determining causality of graft failure can be difficult and depends on medical sophistication of the person entering the data. That being said, there is no reason to believe that the gender of the recipient would bias the presumptive cause of graft failure entered even if the cause of graft failure was incorrect. Second, 28% and 35% of cases, respectively, lacked coding for treated acute rejection at six months and one year. For each time point, the percentage of missing data for acute rejection was similar between the two genders. Although the rates of rejection were similar in the patients in whom coding was present, it is possible that the rejection rates could be different if the missing data were present, and as a result the strength of the conclusion from the acute rejection data must be interpreted in that context. On the other hand, the data from the acute rejection rates is concordant with the findings regarding the rate of immunologic graft loss in this population. This study also demonstrates the shortcomings of using death censored graft failure as a surrogate marker for immunologic failure of the graft. Short-term differences in outcomes previously demonstrated in the analysis of the OPTN database appear by our analysis to be due to nonimmunologic graft failures, mainly due to vascular thrombosis and other nonimmunologic causes of renal failure like acute tubular necrosis due to sepsis. In fact, in the present era of immunosuppression, early graft failure in the first six months due to rejection is a rare event occurring in approximately 1% of transplants in this analysis. In contrast, death with functioning graft occurred in approximately 3% of recipients and vascular thrombosis or primary nonfunction in approximately 1%, respectively. The finding of a higher rate of thrombosis among female recipients was unexpected but is biologically plausible given that estrogen is a prothrombotic hormone and females are more likely to have conditions such as antiphospholipid syndrome or lupus erythematous which are associated coagulation abnormalities that increase the risk of thrombosis.Why H-Y incompatibility did not affect outcomes remains speculative. There are a number of possibilities why one tissue or organ may be more or less susceptible to immunologic attack. One potential explanation for the lack of effect is that H-Y antigen expression on human kidney tissue is absent or weak. There are no published studies of H-Y antigen expression on human kidney tissue. Second, even if the H-Y antigens are expressed on kidneys, the use of potent immunosuppression may prevent kidney rejection in the majority of cases limiting its impact on outcomes. Finally, it is possible that sensitization through previous exposure to the H-Y antigens by pregnancy or previous transplant is necessary before an effect would be seen. One study indicated that the presence of antibodies to H-Y antigens predicted a higher rate of rejection . In our In summary, this analysis of the OPTN database indicates that the male donor to female recipient gender discordance has minimal if any impact on immunologic kidney graft outcomes in the modern era of immunosuppression. Female recipients of male donor kidneys had neither an increased rates of acute rejection in the first year after transplant nor increased risk of graft failure related to rejection.


Arterial stiffening is related to an intricate interplay between aging and other cardiovascular risk factors. The aortic arch accounts for most of the vascular buffering function and is primarily involved in arterial stiffening. MRI has been used to noninvasively measure strain, distensibility, and pulse wave velocity of the ascending aorta. We report aortic size and stiffness changes over mid to late adulthood in longitudinal comparisons with MRI over a 10-year period in the MESA cohort.Changes in the human cardiovascular system are an important aspect of aging. Arterial stiffness, a major determinant of increased systolic pulse pressure, is associated with aging and with the incidence of stroke, ischemic heart disease and heart failure. The proximal aorta accounts for most of the global arterial stiffening and subsequent complications. Aortic stiffness can be described by changes in aortic dimensions such as strain , as well as, combined with pressure, distensibility . Another approach to aortic stiffness is the measurement of pulse wave velocity (PWV). While these changes with advancing age have been established in cross-sectional studies, few longitudinal data exist on the evolution of aortic biomechanical parameters. The aims of this study are to assess the longitudinal changes in central aortic size and stiffness measured with MRI over a 10-year period in the MESA cohort.226 longitudinal studies with aortic imaging by MRI were analyzed. MRI was performed at first in MESA1 , and then in MESA5  after ten years of follow-up. Both exams used 1.5-T whole-body MRI systems and phase contrast cine gradient echo sequence with ECG gating to evaluate aortic size and stiffness. Aortic sagittal oblique plane with black blood sequence was acquired to position the aortic imaging and allowed for the measurement of the distance between the ascending and descending aorta. Images of the ascending and descending aorta were obtained in the transverse plane at the level of the right pulmonary artery perpendicular to the vessel lumen. Aorta analysis was performed using a validated automated software (ARTFUN. INSERM U678). Aortic size, strain and distensibility were reported in the ascending aorta.Table Table We report aortic size and stiffness changes over mid to late adulthood in longitudinal comparisons. Further analyses will reveal the correlates of these alterations in multi-ethnic cohorts.The study is supported by N01 HC 95168, Multi-Ethnic Study of Atherosclerosis (MESA), National Heart, Lung, and Blood Institute (NHLBI).