EHP 120(3):399–405; Sui et al.].The high-production-volume chemical bisphenol A (BPA) is a key component in polycarbonate plastics and is used in a wide variety of consumer products. The U.S. general population is widely exposed to BPA, as demonstrated by the chemical’s presence in more than 90% of biological samples tested. BPA has been associated with cardiovascular disease and diabetes in human population studies, but if causality were to be proven, it is doubtful it would arise from BPA’s known weak interaction with estrogen receptors. Researchers previously determined that BPA targets another nuclear receptor, the pregnane X receptor (PXR), and have now determined that the chemical and several related compounds  can induce metabolically important genes via PXR activation [PXR is activated by numerous endogenous and environmental chemicals. Earlier research established that PXR activation in mice and rats induces genes involved in lipid homeostasis, atherosclerosis, and carcinogenesis. Although PXR is not affected by BPA in rodents, the chemical activates the human receptor and induces target gene expression. This connection suggested a possible mechanism to explain BPA-related cardiovascular disease findings in human populations.In the current study, transfection assays using mouse- and human-derived receptors showed that BPA induces strong, dose-dependent activation of human PXR but not mouse PXR. Computational docking and modeling studies focusing on the structure of human PXR identified key amino acids within the ligand-binding domain that permit BPA to interact with the receptor. These studies also highlighted how species-related differences in this domain can affect how different species respond to specific chemicals.in vitro using site-directed mutagenesis assays that focused on the amino acids critical for BPA docking within PXR. Additionally, several BPA structural analogues were found to activate the PXR. Experiments to determine interactions between BPA and specific analogues showed synergism when BPA was paired with 2-(4'-hydroxyphenyl)-2-phenylpropane (HPP); that is, the effect of the mixture exceeded the sum of the individual chemicals. In a final set of experiments, the ability of BPA and analogues HPP and bisphenol B to separately trigger expression of PXR target genes was tested in a human intestinal cell line. All 3 compounds were found to trigger expression of the metabolic genes CYP3A4, UGT1A1, and MDR1.The modeled predictions were confirmed in vivo experiments.Although this study did not address questions of risk assessment, its findings suggest that BPA may adversely affect human health via PXR and thus provide a foundation for further exploration of the observed association between BPA and cardiovascular disease. Additionally, given the likelihood that real-life exposures involve chemical mixtures, the demonstrated synergism between BPA and HPP supports the need to include mixtures in


N = 21). A delayed match-to-sample task was modified wherein task-irrelevant facial distracters were presented early and briefly during the rehearsal of pseudoword memoranda that varied incrementally in load size . Facial distracters displayed happy, sad, or emotionally neutral expressions. Implicit socioemotional modulation of WM was indexed by subtracting task accuracy on nonfacial geometrical distraction trials from facial distraction trials. Results indicated that the amount of implicit socioemotional modulation of high WM load accuracy was significantly associated with negative symptoms , role functioning , social functioning , and global assessment of functioning . Specifically, greater attentional distraction of high WM load was associated with less severe symptoms and functional impairment. This study demonstrates the importance of the WM-socioemotional interface in influencing clinical and psychosocial functional status in psychosis.This study investigated implicit socioemotional modulation of working memory (WM) in the context of symptom severity and functional status in individuals with psychosis ( Attentional impairments are commonly observed in psychosis . A classWe utilized a WM paradigm  that assgreater symptom severity and functional impairment would be associated with relatively less implicit facial disruption of WM.Viewing implicit socioemotional modulation of WM as adaptive in certain real-world circumstances, we hypothesized that symptom severity and functional status in psychosis are related to attentional distraction of WM by task-irrelevant faces. Specifically, Twenty-one  individuals are diagnosed with schizophrenia, schizophreniform disorder, psychosis NOS, schizoaffective disorder, or an affective psychosis that was confirmed using the SCID-I . Among tSymptom severity was scored on the scales for the assessment of positive symptoms (SAPS ) and negload size (1 versus 2 versus 3 syllables) and distraction  versus nonfacial geometrical oval figure). Stimuli included (1) pronounceable nonwords, (2) human faces , and a Following completion of the task, participants were asked in an open-ended manner whether they “noticed anything in the task.” If a participant did not freely report detecting a face in the task, then they were given a debriefing statement. If participants reported detecting a face during the task, then they were given the facial affect recognition test prior to presentation of the debriefing statement. This test consisted of pictures of facial expressions representing each of the eight emotional expressions  in the Radboud Faces Database . Particiminus 1-syllable/geometrical distraction accuracy” variable, a calculation that was repeated for the 2 and 3 syllable conditions. Effects of facial distracters were collapsed across valence type  because sensitivity to emotional and emotionally neutral faces is common in psychosis  = 23.079, P < 0.001; MSE = 0.01; η2p = 0.536) indicating that responses were most accurate for the 1-syllable condition , intermediately accurate for the 2-syllable condition , and least accurate for the 3-syllable condition . In contrast, no significant main effect of distraction  or load-by-distraction interaction  was detected. Although the interaction failed to reach statistical significance, the partial eta-squared was of moderate strength and the interaction for response latencies was significant . Load had a significant effect on accuracy (All participants reported detecting a face during the task. Fifty-eight percent of the participants reported that they saw a happy face, 91% reported that they saw a neutral face, and 16% reported that they saw a sad face.Results of the present study demonstrate that greater distraction of WM by task-irrelevant faces was associated with less severe symptoms and with more intact global mental-health functioning. These associations were load dependent and were observed only in the high WM load condition. How might these findings be explained? One account begins with the thesis that, because of their biological significance, faces are especially potent attractors of attention in the primate visual system . AdditioMoreover, functional brain imaging studies have shown that not only that task-irrelevant emotional distraction can impair working memory, but also that disruptive emotional stimuli can activate limbic system sites while reducing activity in the dorsolateral prefrontal cortex , 20. We In a sample of individuals with psychosis, the amount of implicit socioemotional modulation of high WM load accuracy was significantly associated with negative symptoms, role functioning, social functioning, and global assessment of functioning. Specifically, greater attentional distraction of high WM load was associated with less severe symptoms and functional impairment. This study demonstrates the importance of the WM-socioemotional interface in influencing clinical and psychosocial functional status in psychosis.


Triple-negative breast cancer (TNBC) is an aggressive type of breast cancer that is clinically defined as lacking estrogen and progesterone receptors, as well as being ERBB2 (HER-2) negative. Without specific therapeutic targets, TNBC carries a worse prognosis than other types of breast cancer in the absence of therapy. Research has now further differentiated breast cancer into subtypes based on genetic expression patterns. One of these subtypes, basal-like, frequently overlaps with the clinical picture of TNBC. Additionally, both TNBC and basal-like breast cancer link to BRCA mutations. Recent pharmaceutical advances have created a class of drugs, poly(ADP-ribose) polymerase (PARP) inhibitors, which are showing potential to effectively treat these patients. The aim of this paper is to summarize the basis behind PARP inhibitors and update the current status of their development in clinical trials for the treatment of TNBC. Breast cancer is a multifaceted, heterogeneous disease whose treatment is evolving as genetic profiles shed more light on potential targets. The understanding of breast cancer became more complex with Perou et al.'s 2000 publication detailing the classification of breast cancer based on gene-expression assays . Among tThe definition of triple-negative breast cancer is based on clinical observations; the tumor must lack estrogen receptors (ERs), progesterone receptors (PRs), and hormone epidermal growth factor receptor type 2 (HER-2) expression. These tumors are particularly vexing for physicians because there are no known endocrine targets nor are there specific receptors to block. Women diagnosed with TNBC tend to be younger  and are There are many similarities between TNBC and basal-like breast cancer, but the two terms are not synonymous . They shOne important similarity between TNBC and basal-like breast cancer is the incidence of mutations in the breast cancer susceptibility gene 1 and 2 (BRCA1 and 2). BRCA mutations are only 2-3% of all breast cancers but signify an increased lifetime risk of breast and ovarian cancer . Somatic Researchers have found the links between TNBC, basal-like breast cancer, and BRCA mutations to be a potential source of directed therapy. One notable avenue is through synthetic lethality. This is a strategy to target and kill specific cell types, without collateral damage. It is achieved by locating a gene that, when inhibited, will kill cancerous cells that contain a specific genetic signature. The inhibitor would not damage normal cells that lack the cancer-specific gene. The design and exploration of poly(ADP-ribose) polymerase (PARP) inhibitors have emerged as a potential target to cause synthetic lethality in cancerous cells while sparing normal mammary tissue. The aim of this paper is to discuss the molecular basis behind PARP inhibitors and an update on their current status in several clinical trials.Poly(ADP-ribose) polymerase (PARP) is a nuclear protein that is activated in the presence of DNA damage. While several PARP proteins have been detected, PARP1 and PARP2 have been associated with DNA stability . When siHomologous recombination is mediated by several factors, including BRCA1, BRCA2, and RAD51 –28. Cellhttp://www.clinicaltrials.gov/). Results of an open-label phase II trial for iniparib  combined with chemotherapy on metastatic TNBC patients were recently published [Several PARP1 inhibitors are being studied at the clinical trial level, and this paper will focus specifically on iniparib, olaparib, and veliparib , but this did not achieve the prespecified criteria for significance (P = 0.01) [At this year's meeting of the American Society of Clinical Oncology, O'Shaughnessy and colleagues presented their results of the phase III iniparib trial. This trial enrolled 519 women and again looked at gemcitabine and carboplatin versus the same regimen with added iniparib. The results did find an increase in progression-free survival amongst the iniparib/gemcitabine/carboplatin arm  . A possiOlaparib  is another PARP1 inhibitor that is being tested on various cancers, including breast. Preclinical models showed an increased selective potency for this compound . The subDespite these encouraging results, London-based drug maker AstraZeneca has decided to suspend olaparib prior to a phase III trial. AstraZeneca has shifted its olaparib focus to ovarian cancer and currently has a phase II trial to study its effects on that cancer type . Veliparib  has been investigated as a single agent  and alsoTNBC is a clinical term used to describe women whose tumors lack expression of ER, PR, and HER-2. This subset of breast cancer partially fits into a molecular subtype known as basal-like breast cancer. Regardless of whether one looks at data through a TNBC or basal-like spectrum, the prognosis is worse compared to other subtypes. While there is no specific treatment regimen for TNBC patients, neoadjuvant therapy has been effective in achieving complete pathologic response (pCR) that subsequently correlates to improved outcome , 44. TNBTherapeutic options for TNBC have the potential to drastically increase in the near future. Combinations of platinum compounds for neoadjuvant therapy are being tested in various clinical trials. Epidermal growth factor receptors (EGFRs) are noted in 45–70% of TNBC , resultiMany potential therapeutic agents are in the pipeline in laboratories worldwide, but PARP inhibitors have the potential to alter the outcome of TNBC patients. In addition to iniparib, olaparib, and veliparib, there are more being constructed. These include CEP-9722 , INO-1001 (Genentech), PF-01367338 (Clovis/Pfizer), and MK-4827 (Merck). Several challenges must still be met to continue advancing PARP inhibitors. Most notably is the fact that recent trial data have landed huge blows to the momentum of PARP inhibitors for breast cancer. At the 2011 ASOC, it was announced that iniparib did not perform at its expected effectiveness in a phase III trial with metastatic TNBC patients. AstraZeneca has maintained an interest in PARP inhibitors, but is doing so through further trials in other organs, such as ovarian. Yet another complication that has emerged is resistance to PARP inhibitors that is being observed in the laboratory . NorquisIt will be imperative to continue exploring the pathway connecting TNBC, basal-like breast cancer, and BRCA. There appears to be more questions to explore and compounds to test in the TNBC population with these therapeutics. Also, further testing is necessary to identify the optimal doses of not only the PARP inhibitor but also any combined chemotherapy. These key components of PARP inhibitor development will hopefully improve the quality of this class of cancer-fighting drugs and provide hope for patients currently facing such bleak diagnoses.


Clover yellow vein virus (ClYVV) causes lethal systemic necrosis in legumes, including broad bean (Vicia faba) and pea (Pisum sativum). To identify host genes involved in necrotic symptom expression after ClYVV infection, we screened cDNA fragments in which expression was changed in advance of necrotic symptom expression in broad bean (V. faba cv. Wase) using the differential display technique and secondarily with Northern blot analysis. Expression changes were confirmed in 20 genes, and the six that exhibited the most change were analyzed further. These six genes included a gene that encodes a putative nitrate-induced NOI protein (VfNOI), and another was homologous to an Arabidopsis gene that encodes a glycine- and proline-rich protein GPRP (VfGPRP). We recently reported that necrotic symptom development in ClYVV-infected pea is associated with expression of salicylic acid (SA)-dependent pathogenesis-related (PR) proteins and requires SA-dependent host responses. Interestingly, VfNOI and VfGPRP expression was correlated with that of the putative SA-dependent PR proteins in ClYVV-infected broad bean. However, broad bean infected with a recombinant ClYVV expressing the VfGPRP protein showed weaker symptoms and less viral multiplication than that infected with ClYVV expressing the GFP protein. These results imply that VfGPRP plays a role in defense against ClYVV rather than in necrotic symptom expression. Virus infections induce a number of disease symptoms such as developmental abnormalities, chlorosis, and necrosis in plants. These symptom expressions not only result from disruption of cell activity by virus infection but also from the complex interplay between plant and virus. Although it is broadly true that symptom severity, e.g., latent to lethal, depends on both viral pathogenicity and plant susceptibility, elucidating how these symptoms are expressed is an enormous challenge to plant virologists.Clover yellow vein virus (ClYVV) is one such case involving defense responses . A BLAST search with the sequence found that the k158 gene product had 55.5% identity at the amino acid sequence level with a glycine- and proline-rich protein (GPRP) in Arabidopsis thaliana [GPRP (VfGPRP). The VfGPRP association with necrotic symptoms was examined by ectopic expression of VfGPRP protein in ClYVV-infected cells using a recombinant infectious plasmid pClYVV/VfGPRP derived from the virus expression vector pClYVV [In this study, the involvement of k158 in necrotic symptom expression in broad bean was examined. An 860-bp full-length cDNA of k158 was obtained by conventional 5' and 3' RACE methods and its nucleotide sequence was determined [DDBJ: thaliana . GPRP isthaliana , HG and r pClYVV . We alsocis effect of the inserted VfGPRP nucleotide and amino acid sequences on replication of the viral genome and/or translation of viral genes. However, the attenuated virulence was partly reversed by the additional insertion of a Myc tag peptide into the hydrophobic domain of VfGPRP on the recombinant ClYVV (ClYVV/VfGPmycRP; Figure These two plasmids and pClYVV/C3-S65T expressing GFP in infected cells  were bioThe authors declare that they have no competing interests.IU designed and coordinated the study. HK and YS screened the broad bean genes using differential display techniques. HK performed cloning and sequencing of the identified genes and analyzed their expression. HK, GA, SHC, and KSN investigated the involvement of the identified genes in viral virulence in broad bean. KSN wrote the manuscript. All authors read and approved the final manuscript.


G12D), which are present in more than 90% of PDAC, have been proven to foster low intracellular ROS levels. Here, oncogenic Kras activates expression of a series of anti-oxidant genes via Nrf2  and also mediates an unusual metabolic pathway of glutamine to generate NADPH. This can then be used as the reducing power for ROS detoxification, leading collectively to low ROS levels in pancreatic pre-neoplastic cells and in cancer cells. In adult stem cells and cancer stem cells, low ROS levels have been associated with the formation of a proliferation-permissive intracellular environment and with perseverance of self-renewal capacities. Therefore, it is conceivable that low intracellular ROS levels may contribute significantly to oncogenic Kras-mediated PDAC formation.Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease without clearly known disease causes. Recent epidemiological and animal studies suggest that the supplementation of dietary antioxidants  decreases cancer risk, implying that increased reactive oxygen species (ROS) may play a role in pancreatic carcinogenesis. However, oncogenic Kras mutations (e.g., Kras KRAS  mutations  have been considered as the initiating genetic event for this disease  in a genetically engineered mouse model (GEMM) of pancreatic cancer  is a highly aggressive tumor entity without clearly known disease causes  cascade ] and non-radical ROS . The free radical ROS has unpaired electrons in the molecular orbital whereas non-radical ROS contains no unpaired electrons  and can alter intracellular signal transduction , intracellular ROS is constantly eliminated via a sophisticated ROS-detoxifying system including non-enzymatic antioxidants  and enzymatic antioxidants  , which is a master switch in the antioxidant network  that continually sustains the intracellular NADPH/NADP+ ratio , which then initiated a set of antioxidant programs. Consistently, human PanINs and PDACs exhibit activation of NRF2 and have low ROS levels in comparison to normal pancreatic ducts cells. NRF2, which is negatively regulated by KEAP1 (kelch-like ECH-associated protein 1), controls the expression of a series of proteins involved in different steps of ROS detoxification—such as NADPH generation  whereas the NAPDH-producing oxidative arm of the PPP remained unaffected . Thus, generation and maintenance of constant intracellular NADPH levels is essentially important. In this regard, a previous study demonstrated that KrasIn conclusion, collaboration between Nrf2-mediated ROS detoxification and the NADPH-generating metabolic program collectively contributes to a “reduced” intracellular environment . Since both of these depend on the activity of oncogenic Kras, it is conceivable that such an intracellular environment constitutes an important step in pancreatic carcinogenesis.As earlier illustrated, prospective studies have suggested an association between dietary antioxidants and a decreased risk for developing pancreatic cancer (Gong et al., low cell population expressed high levels of stemness-associated molecules such as Notch1 and telomerase; it also had a higher self-renewal potential than the ROShigh population of cells (Jang and Sharkis, Although the biological significance of such an oncogenic Kras-mediated reductive intracellular environment remains unclear, this phenomenon has been widely described in other biological systems Table . For exaG12D-driven carcinogenesis in mice (Kong et al., G12D-induced low intracellular ROS levels may facilitate expansion of pancreatic stem/progenitor cells by creating a proliferation-permissive intracellular environment. Furthermore, despite a questionable general compliance of PDAC to the CSCs concept, the heterogeneity of pancreatic cancer tissues indicates that a subset of pancreatic cancer cells may have low intracellular ROS levels in comparison to others.Because early expansion of pancreatic stem/progenitor cells accelerates KrasThe exact contribution of pre-neoplastic and cancer cells with low ROS levels to PDAC initiation, progression and metastasis in humans remains to be defined. Certainly, such a subset of cancer cells may constitute a promising drug target for future therapies. Though the Nrf2-mediated network has been proposed as a potential drug target (Arlt et al., The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


Recent studies indicate that species richness can enhance the ability of plant assemblages to support multiple ecosystem functions. To understand how and when ecosystem services depend on biodiversity, it is valuable to expand beyond experimental grasslands. We examined whether plant diversity improves the capacity of agroecosystems to sustain multiple ecosystem services—production of wood and forage, and two elements of soil formation—in two types of smallholder fallows in western Kenya. In 18 grazed and 21 improved fallows, we estimated biomass and quantified soil organic carbon, soil base cations, sand content, and soil infiltration capacity. For four ecosystem functions  linked to the focal ecosystem services, we quantified ecosystem service multi-functionality as (1) the proportion of functions above half-maximum, and (2) mean percentage excess above mean function values, and assessed whether plant diversity or environmental favorability better predicted multi-functionality. In grazed fallows, positive effects of plant diversity best explained the proportion above half-maximum and mean percentage excess, the former also declining with grazing intensity. In improved fallows, the proportion above half-maximum was not associated with soil carbon or plant diversity, while soil carbon predicted mean percentage excess better than diversity. Grazed fallows yielded stronger evidence for diversity effects on multi-functionality, while environmental conditions appeared more influential in improved fallows. The contrast in diversity-multi-functionality relationships among fallow types appears related to differences in management and associated factors including disturbance and species composition. Complementary effects of species with contrasting functional traits on different functions and multi-functional species may have contributed to diversity effects in grazed fallows. Biodiversity and environmental favorability may enhance the capacity of smallholder fallows to simultaneously provide multiple ecosystem services, yet their effects are likely to vary with fallow management. Biodiversity in its broad sense is responsible for the ecosystem services relied on by human societies In recent decades a growing body of evidence from manipulative experiments has demonstrated that diversity in ecological communities can significantly influence ecosystem functioning Biodiversity effects on ecosystem function are generally attributed to complementarity effects and sampling (or selection) effects. Complementarity effects reflect the net outcome of all biological processes affecting the functioning of an assemblage Biodiversity-ecosystem function research is currently expanding to address multiple ecosystem functions and a broader range of ecosystems. From a more theoretical perspective, the focus on diversity effects on individual ecosystem functions does not embrace the likelihood that species affect different ecosystem functions differently While relatively few studies have addressed plant diversity effects on terrestrial ecosystem function outside of grasslands, a handful of studies have investigated whether plant diversity enhances the capacity to provide multiple functions simultaneously, i.e., ecosystem multi-functionality.Evidence for a greater ability of diverse plant assemblages to support multiple ecosystem functions has emerged from grassland diversity manipulation studies. These studies tested distinct yet related hypotheses: (1) considering a greater number of functions increases the number of species important for functioning 3−Complementarity among plant species, both within as well as among ecosystem functions, may significantly underlie plant diversity effects on ecosystem multi-functionality. That is, plant diversity may improve multi-functionality in part through complementarity effects specific to individual ecosystem functions. Meanwhile, different species providing complementary benefits to different ecosystem functions should further enhance multi-functionality. ‘Multi-functional’ species able to support more than one function may also promote multi-functionality. Some agroforestry trees in our study area are multi-functional: Sesbania sesban (L.) Merr., for instance, is productive, can fix over 70% of its nitrogen content from the atmosphere, and can prevent leaching of soil NOIn agroecosystems, plant diversity might influence multiple ecosystem functions more strongly than in experiments. Management practices such as harvesting, grazing, and land use rotations cause significant disturbance. Stronger effects of diversity on ecosystem function in the presence of disturbance The potential of biodiversity to buffer ecosystem functioning against environmental change is known as the insurance hypothesis When a biotic community experiences a perturbation, the importance of functional trait diversity depends on whether the traits engendering vulnerability (response traits) also determine species effects on ecosystem function (effect traits). When species with strong effects are more vulnerable, ecosystem function declines more severely than with random species loss Plant responses to aboveground biomass removal are mediated by traits associated with two main strategies: tolerance and avoidance. The first suite of traits enables plants to withstand disturbance, such as resprouting ability At global scales, large herbivore grazing tends to favor annuals (indicating avoidance) and short, prostrate, or stoloniferous plants (indicating tolerance) Manihot esculenta Crantz), for instance, is a major food crop globally Sesbania in our study site).In addition to disturbance, tropical smallholder agroecosystems have further characteristics that may increase the likelihood of plant diversity influencing ecosystem multi-functionality. Smallholder farms tend to be more multi-functional The goal of the current study is to assess whether plant diversity and environmental conditions influence the capacity of tropical smallholder fallows to provide multiple ecosystem services. A set of four ecosystem functions were selected as indicators for the ecosystem services of wood production, livestock forage production, and soil formation, the latter of which affects post-fallow crop production. Ecosystem service multi-functionality was quantified as (1) the proportion of ecosystem functions above half-maximum , and (2) mean percentage excess above mean ecosystem function values (“mean percentage excess”). Two specific hypotheses were tested: first, plant diversity increases the ecosystem multi-functionality of fallows; and second, multi-functionality increases with environmental favorability, in terms of lower grazing intensity  and higher soil fertility, since favorable environmental conditions may benefit each ecosystem function. Here we present the first assessment of plant diversity influences on multiple ecosystem functions in the humid tropics, and the first test of biodiversity influences on multiple ecosystem functions directly linked with ecosystem services relevant to smallholder farmer livelihoods.Correlations among the selected set of four ecosystem functions were weak in both grazed and improved fallows, with the exception of the negative correlation between wood biomass and forage biomass in improved fallows. Wood and forage biomass were positively and marginally significantly correlated  in grazeEcosystem multi-functionality, in terms of the proportion of ecosystem functions above half-maximum  and mean percentage excess above mean function values (“mean percentage excess”), varied more widely in grazed than in improved fallows . The proF = 12.2; P<0.01) and functional diversity  of fallow plants . While the proportion above half-maximum declined with grazing intensity, mean percentage excess was not associated with grazing intensity, and neither indicator correlated with soil carbon , nor was soil carbon .In linear models combining grazing intensity with plant diversity variables, functional diversity and species richness had marginally significant effects on the proportion above half-maximum, and remained significant predictors of mean percentage excess, while grazing intensity was not a significant predictor of either multi-functionality indicator , 3. For R2 = 0.582; P<0.05) and mean percentage excess  again increased with functional diversity , while the sample was small at low grazing intensity (n = 4), and diversity varied little at high grazing intensity. As such, the moderately grazed group  provided the most meaningful test of diversity effects on multi-functionality within a single grazing group. In moderately grazed fallows, the proportion above half-maximum , soil base cations , or infiltration  in grazed fallows, although infiltration rates were lower in grazed than in improved fallows . Soil carbon was correlated with base cations  in grazed fallows, but not with infiltration .Soil base cations and infiltration rates jointly exceeded 50% of maxima or mean values in only a few grazed fallows. The probability distributions of base cations and infiltration were skewed left-ward and the incidence of jointness was lower than in improved fallows . Grazingr = 0.446; 95% CI ) in improved fallows, base cations were not .In improved fallows, approximately half the sample exhibited jointness for soil base cations and infiltration rates , despiter = 0.562; 95% CI ), and was not significantly associated with their contents of N or polyphenols. Forage biomass in grazed fallows increased with tissue N content of forage species . Increased soil carbon and infiltration rates with green tissue content of recalcitrant C compounds, i.e., lignins+polyphenols, were documented in the study fallows . Although soil carbon was closely correlated with soil base cations , base cations and content of lignins+polyphenols were not significantly correlated in grazed fallows .In grazed fallows, wood biomass increased with the abundance-weighted mean for green tissue lignin content of trees and shrubs  and mean percentage excess above mean ecosystem function values (“mean percentage excess”) increased with functional diversity and species richness. The decline in the proportion above half-maximum with grazing intensity explained less of the variance than did plant diversity variables, and no such decline was observed for mean percentage excess. Positive effects of fallow plant diversity on ecosystem multi-functionality were stronger than negative effects of grazing, yet it was not unequivocally clear that diversity effects were independent of variation in grazing intensity. It remains possible that more intense grazing, perhaps in conjunction with variation in soil conditions, could have influenced plant diversity or altered diversity effects. Significant effects of functional diversity on multi-functionality in moderately grazed fallows indicated that within this group of fallows, effects of functional diversity on both the proportion above half-maximum and mean percentage excess were independent of grazing.r = 0.202; 95% CI ) and species richness . Despite the weakness of these associations, greater diversity in more productive sites could have contributed to diversity effects on mean percentage excess.In improved fallows, there was mixed evidence for effects of plant diversity and environmental conditions on ecosystem multi-functionality. Improved fallows typically sustained at least two of the four ecosystem functions above half-maximum, irrespective of both diversity and soil carbon. In contrast, mean percentage excess increased with both diversity and soil carbon, with soil carbon out-performing diversity variables as a predictor. Positive effects of soil carbon on mean percentage excess indicated that multi-functionality may have been more easily attained under environmental conditions favorable for the production of biomass, development of soil structure and improvement of infiltration, and the deposition of base cations in litter and their retention in soils. Environmental favorability appeared more influential than plant diversity, and the potential of diversity to benefit multiple ecosystem functions in improved fallows was uncertain. In improved fallows soil carbon was positively though weakly associated with plant functional diversity , multi-functionality could be predicted from the values of individual functions alone. However, the presence of species providing complementary benefits to different functions may contribute, in part, to diversity effects on multi-functionality. Complementary effects of species on different functions may occur alongside complementarity effects specific to individual functions, and multi-functionality was expected to increase when species are complementary both within and among ecosystem functions.In grazed fallows, wood originates from trees and shrubs, and forage primarily from herbaceous species. Different functional traits were associated with and may have benefitted these two components of fallow biomass. Wood biomass increased with green tissue content of lignins, and since wood declined with grazing intensity, the correlation between wood and tissue lignin suggests that less palatable woody plants were more successful in the presence of grazing. In contrast, forage biomass increased with green tissue N, and also declined with grazing intensity, suggesting that less palatable forage species prevailed under intense grazing. Thus, not only are wood and forage produced by different subsets of the assemblage, they appeared to increase with divergent functional traits, and therefore appear to benefit from plant species with complementary influences on wood versus forage production. As such, high levels of both wood and forage should co-occur where species have high content of either lignins or N. As calculated here, greater functional diversity would meet this condition, since high lignin values were uncommon, and herbaceous lignin content was particularly low.unpublished data)—the joint occurrence of high wood biomass with high infiltration and base cations may be more likely in plant assemblages including species with high content of either lignins or polyphenols. Again, such a combination of traits would coincide with higher functional diversity.While wood biomass increased with lignin content, polyphenol content was negatively though insignificantly associated with wood biomass. Since infiltration and soil carbon (which correlated with soil base cations) responded positively to vegetation with higher tissue content of recalcitrant C compounds—lignins+polyphenols in particular  and forage biomass  indicated that intense grazing reduced the biomass of the overstory as well as forage species, generating the positive association between wood and forage biomass  conducted an experiment with improved fallow monocultures and two-species mixtures. While monocultures and mixtures produced similar amounts of biomass, mixed fallows out-performed monocultures on average in terms of N recycled to soils and post-fallow maize yields, although a monoculture performed best for both functions. Thus, while complementarity may enhance multiple ecosystem services in improved fallows, the potential may be limited and dependent on species composition.The observed relationships among plant diversity, environmental conditions, and ecosystem service multi-functionality differed substantially between grazed and improved fallows. In grazed fallows, significant effects of plant diversity on multi-functionality indicators provided evidence in support of plant diversity enhancing the capacity of fallows to provide multiple ecosystem services. Diversity effects on multi-functionality were stronger and more consistent than negative effects of grazing intensity. In contrast, soil carbon appeared more influential than diversity in improved fallows, and evidence for diversity effects on multi-functionality was scant. The ecological factors influencing multi-functionality thus appeared to differ appreciably among fallow types, with plant diversity more influential in grazed fallows and environmental favorability more important in improved fallows.Differences in management between grazed and improved fallows created contrasting ecological conditions that may explain much of the apparent divergence in ecological controls over ecosystem multi-functionality. The improved fallows here were ungrazed and experienced little disturbance, while grazed fallows were subjected to consistent disturbance from livestock grazing. The other major management difference was that improved fallows were intentionally planted with leguminous trees and large-statured shrubs, while the vegetation in grazed fallows reflected largely unguided regeneration. These management dissimilarities were likely responsible for generating the prevailing differences in vegetation structure and species composition among fallow types.The results indicate that the management of smallholder fallows influences the relationship between plant diversity and ecosystem service multi-functionality. The productive, multi-functional species planted in improved fallows were highly dominant, generating competition and limiting variation in plant diversity, functional traits, and the abundance of multi-functional species. As a result, fallow management to create dense stands of woody legumes appeared to reduce or obscure the potential for plant diversity to affect multi-functionality. In contrast, grazing disturbance and unguided regeneration in grazed fallows led to variation in plant diversity, functional traits, and multi-functional species abundance, and reduced dominance and competition (and possibly increased facilitation). Effects of plant diversity on multi-functionality in grazed fallows therefore appear related to management of fallows with livestock grazing and without planting woody legumes. The results from grazed fallows are consistent with complementary benefits of different plant species to different ecosystem functions and multi-functional species being among the sources of positive influences of plant diversity on ecosystem service multi-functionality.To improve understanding of the relationship between biodiversity and ecosystem service multi-functionality, research investigating sources of variation in the relationship is a sensible extension of the findings presented here. Disturbance and perturbations, environmental conditions, dominance, and species interactions—all recognized as significant in previous biodiversity-ecosystem function research—are promising avenues toward more fully elucidating the potential significance of plant diversity in sustaining the ability of agroecosystems to provide multiple ecosystem services, and the possible roles of biodiversity in maintaining the overall functioning of ecosystems managed and natural alike.th century The Millennium Villages Project (MVP) is an evidence-based approach to alleviating extreme rural poverty in sites throughout Sub-Saharan Africa, in which agricultural development plays a strategic role Tephrosia candida DC, and less commonly Crotalaria paulina Schrank, Calliandra calothyrsus Meissn. and other exotics, or the native Sesbania sesban (L.) Merr. Improved fallows in the present study were not grazed with livestock. Grazed fallows, often considered a type of ‘natural’ or ‘weed’ fallow, are less common, and contain a variety of mostly native species. Trees common in grazed fallows include the native Sesbania and Markhamia lutea (Benth.) K. Schum., and the exotic Psidium guajava L. Most grazed fallows combine production of wood and green manures with livestock grazing, although the most heavily grazed fallows produce little or no wood.‘Improved’ fallows of fast-growing leguminous trees and shrubs are promoted by MVP to improve soil fertility and produce fuelwood. Improved fallows in the area are primarily 2 plot located randomly in the interior of each fallow. Soil samples were collected and soil infiltration capacity measured in two 2 m2 subplots, one in the plot center, and one randomly located tangent to the plot edge. Biovolume (m3) of all vascular plant species was characterized by visually estimating cover and average height. Cover was scored as the mid-point of cover classes on a 5-point scale: 1–4, 4–15, 15–40, 40–65, and >65%. Grazing intensity was recorded by visually estimating cover for evidence of grazing—trampling, feces, bite marks, and hair—on the same 5-point scale, and fallows placed into groups of lightly (4–40%), moderately (40–65%), and heavily (>65%) grazed.Fallow fields identified for sampling ranged in size from 0.02 to 0.25 ha, with a mean of approximately 0.1 ha. Data were collected from 18 grazed and 21 improved fallows using a down-scaled version of the Land Degradation Surveillance Framework (LDSF) protocol −1) was estimated by using DBH to calculate whole-tree biomass (Y) by the general allometric equation, Y = elnDBH) was multiplied by a conversion factor to estimate aboveground biomass , the lower asymptote approached by infiltration rate over time. Each ∼2.5 hr measure was modeled as a random effect in a non-linear mixed effects model of the Horton equation Soil organic carbon, soil base cations, and soil sand content were quantified using near infrared reflectance spectroscopy (NIRS), utilizing extensive soil libraries from the study site and the region to predict values of soil properties r2 values of: 0.98 for N; 0.73 for lignin; and 0.86 for polyphenols. Mean trait values were calculated by species. For species not sampled in study plots, mean trait values by species were obtained from the Organic Resource Database Samples of leaves and young green twigs (leaves only for herbaceous species) were collected from a subset of study plots, and NIRS was used to predict content of N, lignins and polyphenols for most common species. Predictions were made using partial least squares regression to model N, lignins, and total soluble polyphenols from PCs of first-derivative NIR spectral reflectance in the 1250 to 2500 nm range. Independent sample cross-validation yielded model fit For the ecosystem service of wood production, the ecosystem service providers, or ESPs For the ecosystem service of forage production, the ESPs were taken to be the forage species producing higher quality forage in terms of the green tissue crude protein  to lignin ratio Species richness was calculated as the number of species comprising ≥1% of standing green biomass in a fallow. The influence of species with low plot-scale abundance on ecosystem functioning is likely to be minor; these species disproportionately influence evenness and are likely to bias estimation of any influences of plant diversity on ecosystem functioning. Although species richness and evenness were negatively correlated, when species comprising <1% of green biomass were removed, the correlation was effectively eliminated.Functional diversity (FD) was used as a proxy for niche complementarity among fallow plant species Ecosystem functions directly related to specific ecosystem services served as indicators of the focal ecosystem services, and each is relevant to the livelihoods of smallholder farmers in the study area. Because total standing green biomass and soil carbon were correlated to varying degrees with other ecosystem functions, collinearity among functions could have biased analysis of ecosystem multi-functionality. Instead, a conservative approach to ecosystem multi-functionality was adopted. The ecosystem functions selected for analysis  were: stIn these agroecosystems, each ecosystem function reflects specific stocks or fluxes of energy, materials, or both. Wood biomass specifically indicates the stock of non-living aboveground biomass, and the potential flux of C, energy, and nutrients in wood to households for fuelwood, poles, etc. Forage biomass is the stock of biomass available for consumption by livestock, and reflects the potential flux of C, energy, and nutrients to livestock biomass and waste. Soil base cation content integrates the cycling, movements, and soil functions provided by Mg, Ca, and K, including cation retention and exchange, plant uptake, leaching and prevention thereof, and retrieval from the subsoil by deep-rooted plants. Soil infiltration capacity is indicative of robust soil structure, avoidance of runoff and soil erosion, and retention and availability of soil water to plants.Fallow ecosystem service multi-functionality among the 4 selected ecosystem functions was quantified by means of 2 indicators: (1) the proportion of ecosystem functions above half-maximum , and (2) the mean percentage excess above mean function values (“mean percentage excess”). That is, “proportion above half-maximum” is the proportion of the 4 ecosystem functions that were higher than 50% of the respective maximum value of each function, and “mean percentage excess” is the mean of the percentage by which ecosystem functions exceeded their mean values. The maximum for each function in the grazed and improved fallow types was defined as the mean of the 3 highest values in each fallow type. One mean and one maximum was established for each function in each fallow type among the two sampling years, as forage biomass did not differ between 2008 and 2009 (not presented), and is the only function likely to vary across years with rainfall and other climatic conditions. The proportion of functions above 25 and 75% of maxima were also calculated. Ecosystem functions were transformed  prior toAll analyses were conducted with R software Figure S1Variation among fallow types in ecosystem multi-functionality in terms of the proportion of ecosystem functions above 25, 50, and 75% of respective function maxima.(PDF)Click here for additional data file.Supplement S1Pair-wise jointness among ecosystem functions.(DOC)Click here for additional data file.Table S1Plant diversity and environmental variables serving as predictors of fallow ecosystem multi-functionality.(DOC)Click here for additional data file.Table S2Derivation of growth form-specific biovolume to biomass conversion factors.(DOC)Click here for additional data file.


Fucus spp. and Mastocarpus stellatus, suggesting that the effects of these canopy-forming algae, known to function as ecosystem engineers, may explain part of the observed variability in community structure. Our findings suggest that broad-scale processes affecting species performance increase ecological variability relative to the pervasive fine-scale patchiness already described for marine coasts and the well known variation caused by vertical stress gradients. Our results also indicate that experimental research aiming to understand community structure on marine shores should benefit from applying a multi-scale approach.In rocky intertidal habitats, the pronounced increase in environmental stress from low to high elevations greatly affects community structure, that is, the combined measure of species identity and their relative abundance. Recent studies have shown that ecological variation also occurs along the coastline at a variety of spatial scales. Little is known, however, on how vertical variation compares with horizontal variation measured at increasing spatial scales . Because broad-scale processes can generate geographical patterns in community structure, we tested the hypothesis that vertical ecological variation is higher than fine-scale horizontal variation but lower than broad-scale horizontal variation. To test this prediction, we compared the variation in community structure across intertidal elevations on rocky shores of Helgoland Island with independent estimates of horizontal variation measured at the scale of patches (quadrats separated by 10s of cm), sites (quadrats separated by a few m), and shores (quadrats separated by 100s to 1000s of m). The multivariate analyses done on community structure supported our prediction. Specifically, vertical variation was significantly higher than patch- and site-scale horizontal variation but lower than shore-scale horizontal variation. Similar patterns were found for the variation in abundance of foundation taxa such as  During the last several years, it has become evident that the different processes that affect species distribution operate and generate variability at different spatial scales The rocky intertidal habitat is a unique system because a strong environmental stress gradient occurs within a few metres from low to high elevations In recent years, variability in intertidal community structure has been increasingly evaluated at different horizontal scales in terms of spatial resolution Another approach to investigating scale effects in ecology is to focus on sampling interval, that is, the average distance between sampling units from which variation in ecological properties is calculated. Using this meaning of scale, it is thought that broad-scale processes may add extra variability to the patchiness commonly observed at fine scales on rocky shores In this paper, we report the results of a study done using rocky intertidal systems from the cold-temperate shores of Helgoland Island, NE Atlantic. We tested the hypothesis that vertical variation in community structure is higher than fine-scale horizontal variation but lower than broad-scale horizontal variation. To test these predictions, we used a nested sampling design to quantify species abundances across the desired horizontal spatial scales in terms of differences in sampling interval. To help explain the observed community patterns, we also analysed the variability in the abundance of the species with the highest contribution to the spatial variation in community structure.We evaluated vertical and horizontal patterns in rocky intertidal community structure in July–August 2008 on 3 shores on Helgoland Island, which is located off the coast of mainland Germany, NE Atlantic : Bunker A nested sampling design was employed. On each of the 3 study shores, we randomly established 3 sites that were spaced 5–10 m from one another following the shoreline. Within each site, we randomly established 2 patches that were spaced a few m from one another. At each patch, we randomly deployed three 25 cm×25 cm quadrats that were spaced a few 10s of cm from one another at each of 3 intertidal elevations .Fucus spiralis, because this is the sessile, perennial species occurring highest on the 3 shores. Once the upper boundary was determined on each shore, we divided the intertidal range in three zones of equal vertical extent . We took all elevation measurements to the nearest cm using a theodolite and a tide pole. All boundaries were permanently marked with screws bolted to the rocky substrate. The upper intertidal boundary was 2.3 m at Bunker, 1.8 m at Kringel, and 2.0 m at Nord-Ost-Hafen.On each shore, we surveyed the full vertical range of elevation between 0 m and an upper intertidal boundary determined using ecological indicators. On marine shores, waves during high tides wash the substrate at higher elevations than the high-water level indicated by tide tables (which provide predictions for still-water conditions). Thus, the regular occurrence of wave action expands the vertical range where sessile organisms can live, so different elevation zones  are wider and higher as wave exposure increases For each quadrat, we identified all seaweeds and invertebrates (>1 mm) using field guides For each quadrat, we measured the percent cover of each species using a 25 cm×25 cm frame divided in 100 equal sections with monofilament line. For data analyses, it was important to have abundance data expressed in the same measurement unit for every species. We chose percent cover to quantify abundance because alternative measures  cannot always be determined reliably for clonal organisms a priori hypothesis to produce an ordination plot, so they allow one to detect patterns that could be masked by overall dispersion in unconstrained methods such as multidimensional scaling. We generated CAP ordination plots for each shore on the basis of a matrix of factors  fitted to a matrix of Bray-Curtis dissimilarities. We assessed the significance of fits with 1000 permutations.To reveal spatial patterns in community structure on the studied shores, we used canonical analysis on principal coordinates (CAP), In nested designs, sampling effort  increases lower in the hierarchy of scales, which prevents a direct comparison of the magnitude of variation among the different scales though hierarchical analysis of variance elevations – MSresidual)/n residual thus corresponded to the pseudo-variance component for horizontal variation. We applied PERMANOVA to measure horizontal variation at the different desired scales  in the way explained below.To measure vertical and horizontal variation in community structure, we used PERMANOVA based on Bray-Curtis distances between pairs of quadrats To measure vertical variation in community structure across the three elevation zones and horizontal variation at the patch scale (variation among quadrats 10s of cm apart within patches), we randomly selected one site from each shore. We used one-way PERMANOVAs separately for each available patch to measure variation. Six patches were available for this analysis (3 shores ×1 site selected per shore ×2 available patches per site), yielding 6 independent estimates of vertical variation and 6 estimates of horizontal variation at the patch scale.To measure horizontal variation at the site scale (variation among quadrats a few m apart within sites), we randomly selected another site from each shore. For each elevation zone within each site, we pooled the quadrats from both patches and, then, randomly divided the resulting 6 quadrats into 2 groups of 3 quadrats each. For each site, we then generated 2 data sets, each one including species abundance data from 3 quadrats from each elevation zone. We then applied one-way PERMANOVAs separately to each data set to generate 2 measures of horizontal variability for each site using the residual mean squares. In this case, horizontal variability measured variation within patches plus the variation between patches within sites. Six data sets were available for this analysis (3 shores ×1 site selected per shore ×2 modified sets of quadrats within each site), yielding 6 estimates of horizontal variation at the site scale.To measure horizontal variation at the shore scale (variation among quadrats 100s to 1000s of m apart), we used the abundance data from the remaining site within each shore. First, we pooled the quadrats from each elevation zone across the 3 shores. Then, we randomly divided the resulting 18 quadrats into 6 groups of 3 quadrats each. We then randomly generated 6 data sets, each one including abundance data from 3 quadrats from each elevation zone. After applying one-way PERMANOVAs separately to those data sets, we obtained 6 measures of horizontal variation using the residual mean squares. In this case, horizontal variability measured variation within patches plus variation between patches within sites plus variation among shores.We also calculated univariate variance components based on the abundance of the taxa contributing most to the spatial variation in community structure, for which we used the quadrat grouping procedure described above for the multivariate approach. For the univariate analyses, we used one-way ANOVAs to obtain estimators of variance. When negative variance components (either multivariate or univariate) were obtained for any scale, we set them to zero under the assumption that they were sample underestimates of small or zero variances 10(y + 1) or square-root transformation of the data. After significant differences among treatments were detected by the ANOVA, we ran Dunnett's tests to evaluate the significance of pairwise differences. We considered Dunnett's test appropriate for our goals because this test compares each group against a “control” group, which in this case corresponded to the vertical variation. SIMPER routines were conducted with PRIMER v6. We did all other statistical analyses and ordinations with R environment version 2.12.2 We tested the hypothesis that vertical variation in community structure is larger than fine-scale horizontal variation but smaller that broad-scale horizontal variation by applying a one-way ANOVA to the multivariate pseudo-variance component data obtained as explained above for each scale. In a similar way, we tested the same hypothesis for the variance component data of the taxa with highest contributions to the spatial variation in community structure. We considered “type of variation” as a fixed factor with 4 levels: vertical variation and patch, site, and shore-scale horizontal variation. We confirmed the homoscedasticity assumption by running Levene's tests after graphical exploration of residuals vs. fitted values and logMastocarpus stellatus, canopy-forming brown algae of the genus Fucus , crustose algae , and the acorn barnacle Semibalanus balanoides. The most common grazers and carnivorous invertebrates were periwinkles of the genus Littorina  and the green crab Carcinus maenas, respectively. The complete list of species appears in a related publication that utilised the abundance data to investigate vertical trends in species diversity as predicted by an environmental stress model F. spiralis, F. serratus , and M. stellatus explained over 50% of dissimilarities across all comparisons  among the 3 studied shores. Four sessile taxa were present in at least 30% of the quadrats, exhibiting a mean percent cover higher than 20%: the turf-forming red alga parisons .P<0.005). Differences among sites within shores were less marked, although they were indeed clear in some cases. For example, at the high intertidal zone of Bunker, quadrats from sites 1 and 3 were well separated in the multivariate space -transformed data: F3, 20 = 39.53, P<0.001). Vertical variation in community structure was significantly higher than patch- and site-scale horizontal variation and significantly lower than shore-scale horizontal variation (P<0.05).Multivariate pseudo-variance components significantly differed among the studied types of spatial variation . For Fucus spp., the vertical variation in abundance was significantly higher than patch- and site-scale horizontal variation  and statistically similar to shore-scale horizontal variation (P>0.05). For M. stellatus, the vertical variation in abundance was significantly higher than patch- and site-scale horizontal variation and significantly lower than shore-scale horizontal variation (P<0.05).The type of spatial variation also had significant effects on variance components for The pronounced vertical variation in community structure found on Helgoland shores corroborates previous findings for other intertidal systems Littorina littorea and competition for space between mussels and Fucus spp. structured communities at middle elevations, while predation by Carcinus maenas shaped communities at low elevations Mastocarpus stellatus, has been followed by a reduction in the abundance of mussels and an associated change in community structure The vertical gradient of abiotic stress that occurs in rocky intertidal habitats determines changes in the intensity of interspecific interactions that also influence vertical patterns in community structure It is now relevant to ask what factors might have determined the larger horizontal variation in community structure measured at the shore scale compared with vertical variation across elevations. On Helgoland Island, propagules are transported away from coastal waters Fucus spp. and M. stellatus, are known to have strong effects on the assembly, maintenance, and resilience of community structure M. stellatus negatively influences post-settlement mortality of F. serratus at Bunker Chondrus crispus, morphologically similar to M. stellatus, affects recruitment of F. evanescens in eastern Canada M. stellatus and Fucus spp. are often the most abundant taxa M. stellatus showed the same spatial patterns of variability in abundance than the patterns of variation found for community structure, hinting for potential canopy effects of this bioengineer on many other species. Fucus spp. also showed a higher degree of variation in abundance at the shore scale than at the two finer horizontal scales, again suggesting that the dominant canopy-forming seaweeds may have strongly contributed to making a large broad-scale horizontal variation in community structure.Foundation species, such as in situ measurements using dynamometers have revealed that wave exposure is higher at Bunker than at Nord-Ost-Hafen and Kringel, being similar between these last two shores Physical attributes of marine shores may also affect broad-scale patterns in community variability. For example, differences in substrate topography and roughness may influence species composition through indirect effects on herbivore activity Our study conducted on cold-temperate NE Atlantic shores supports the previous findings of a study done on warm-temperate NW Mediterranean shores In summary, ours is the second study comparing ecological variation across a well known vertical gradient of environmental stress  with variation occurring at a variety of spatial scales  along the coastline. Our multivariate analyses have indicated that vertical variation in community structure was larger than horizontal variation at fine scales but smaller than that at broad scales. In turn, the univariate analyses on dominant taxa suggest that variation in the abundance of canopy-forming species may have contributed to generating the large degree of variation in community structure observed at the shore scale. In other words, broad-scale processes may add an important amount of variability to the pervasive small-scale patchiness observed along marine shores. Future studies on species distribution and community structure should benefit from applying a multi-scale approach in the face of increasing frequency and intensity of climate-change related impacts on natural communities and resources.


ATP) channel, mitochondrial permeability transition pore (mPTP), reactive oxygen species (ROS) production, as well as through cytoprotective Akt and extracellular-signal kinases (ERK) pathways. However, as not all studies have demonstrated improved outcomes, the risks for undesirable hemodynamic effects must be weighed against the possible benefits of using volatile anesthetics as a means to provide cardiac protection in patients with coronary artery disease who are undergoing surgery.This review evaluates the mechanism of volatile anesthetics as cardioprotective agents in both clinical and laboratory research and furthermore assesses possible cardiac side effects upon usage. Cardiac as well as non-cardiac surgery may evoke perioperative adverse events including: ischemia, diverse arrhythmias and reperfusion injury. As volatile anesthetics have cardiovascular effects that can lead to hypotension, clinicians may choose to administer alternative anesthetics to patients with coronary artery disease, particularly if the patient has severe preoperative ischemia or cardiovascular instability. Increasing preclinical evidence demonstrated that administration of inhaled anesthetics - before and during surgery - reduces the degree of ischemia and reperfusion injury to the heart. Recently, this preclinical data has been implemented clinically, and beneficial effects have been found in some studies of patients undergoing coronary artery bypass graft surgery. Administration of volatile anesthetic gases was protective for patients undergoing cardiac surgery through manipulation of the potassium ATP (K Volatile anesthetics (VA) are gases that are used to induce and maintain general anesthesia, with benefits of relatively rapid onset and recovery with acceptable effects on peripheral organs in most patients. In 1275 Spanish physician Raymond Lullus made a volatile liquid that he called “sweet vitriol”—diethyl ether—which was later used as an anesthetic. Years later, an American physician, Crawford W. Long, noticed that colleagues under the influence of ether felt no pain when they injured themselves. In 1842, Long conducted the first surgery with the use of ether as an anesthetic, his patient, undergoing removal of a tumor in his neck, did not report pain. Long published his report in 1849, after William T. G. Morton had performed the first public demonstration of successful ether anesthesia in the operating amphitheater of Massachusetts General Hospital on October 16, 1846 [VA have been shown to offer benefits in a wide range of medical situations such as use in stroke victims by reducing the amount of ischemic injury during the event of stroke and delaying the development of brain injury ,3; or asThis review will focus on isoflurane, desflurane, and sevoflurane as agents used to achieve cardioprotection emphasizing recent laboratory and clinical data on the use of inhaled anesthetics for cardioprotection. It also discusses the possible cardiac risks associated with inhaled anesthesia.The literature search for this review focused on the volatile anesthetics isoflurane, desflurane, and sevoflurane. The following search conditions were used for each volatile anesthetic: volatile anesthetic AND cardiovascular protection, OR cardiac ischemia, OR cardiac injury, OR cardiac toxicity, OR cardiac ischemic preconditioning, OR myocyte toxicity, OR myocyte ischemia, OR myocyte hypoxia, OR cardiac hemorrhage, OR cardiac tolerance, OR cardiac postconditioning, OR cardiac preconditioning, OR myocyte apoptosis, OR cardiac arrhythmias. Articles that were not available in English were excluded from the references. The available literature is discussed as related to key areas of cardioprotection research and clinical care.2) demand exceeds O2 supply. In the event of ischemia, the myocardium continues to function by utilizing its stores of glycogen. However, if oxygen deprivation occurs for more than 15 minutes the myocardial tissue will become necrotic and lead to irreversible damage through tissue death [Ischemic injury is a pathological process that occurs when blood supply is interrupted to a specific area of tissue that occurs when oxygen  channel. KATP channels are located on mitochondrial, sarcolemmal and nuclear membranes of cardiomyocytes, and are also found in the brain, pancreatic β cells, skeletal and smooth muscle, and neurons [ATP channels leads to generation of reactive oxygen species (ROS), activating downstream kinases, resulting in cardioprotection [ATP channels leading to a reduction in ROS. Thus an initial increase in ROS stimulated by ischemia leads to activation of pathways that result in reduction of ROS. In addition, activation and expression of KATP channels promotes action potential shortening and energy conservation, which is protective by preserving the cardiac tissue [Additional research has linked several intracellular signaling pathways to the phenomenon of ischemic preconditioning. The primary target in all of these pathways appears to be the adenosine triphosphate (ATP)-sensitive K + , which causes collapse of the mitochondrial membrane, uncoupling oxidative phosphorylation, resulting in ATP depletion and cell death. Ischemia also leads to conversion of xanthine dehydrogenase to xanthine oxidase in cardiomyocytes due to the lack of oxygen for metabolism. Xanthine oxidase leads to a build-up of hypoxanthine [Ischemic injury leads to reperfusion injury, when blood flow is restored to an ischemic area. The process of reperfusion leads to severe Caanthine . Upon reATP blockers 5-HD  and HMR-1098  as well as a KATP activator, diazoxide, they were able to show that isoflurane and sevoflurane prime the mitochondrial KATP channel but do not affect the sarcolemmal KATP channels. Zaugg and colleagues explained that sevoflurane and isoflurane administration lead to activation of mitochondrial KATP channels as is similarly seen in ischemic pretreatment. This same research group showed that outcome following coronary artery bypass surgery was improved by sevoflurane compared to placebo pretreatment, reducing the incidence of late cardiac ischemic and congestive heart failure [The administration of anesthetics activates or primes some of the same pathways that lead to protection from ischemic preconditioning. Zaugg et al.  verifiedfailure . Howeverfailure . Warltiefailure . In thisfailure -31. Pirifailure -39ATP channel, and the mitochondrial KATP channel [Additional mechanisms have been elicited that appear to be involved in cardioprotection as a result of preconditioning. These mechanisms include the Akt, ROS, and ERK pathways ,34,39-49channel ,48,50-85ATP channel activation, mPTP modulation and the cytokine pathways (Akt/PI3K). KATP channels, established as cardioprotective mediators in ischemic preconditioning, have been studied in VA pretreatment. It has been shown that opening of the mitochondrial KATP channel leads to generation of ROS [ATP channel opening. Rat trabeculae underwent ischemia and then 60 minutes of reperfusion, and the recovery of active force was used as a measure of cardiac function following myocardial infarction (MI). Sevoflurane improved recovery of active force to 67% as opposed to 28% in the control group. However, when the KATP channel inhibitor (5-HD) was administered along with sevoflurane force recovery was only 31%, while the administration of a ROS scavenger and sevoflurane resulted in force recovery of only 33%. This data indicates that both the KATP channel and ROS are involved in the protective mechanisms of sevoflurane. According to Marinovic et al. [ATP channel is an effector of pretreatment whereas mitochondrial KATP channels are both a trigger and an effector. This was established when both mitochondrial and sarcolemmal KATP channel inhibitors were administered during isoflurane pretreatment in rat cardiomyocytes and a reduction in protection from the sevoflurane pretreated group was observed with 5-HD but not with HMR-1098. However, if HMR-1098 was applied throughout the experiment rather than during just pretreatment, the protective effect was abolished.Several key mechanistic pathways and regulators that have been identified as mediators in the protective effects of pretreatment with VAGs including K of ROS . In a st of ROS  demonstrATP channel is also linked to the mPTP. With this study it was suggested that both ischemic preconditioning and VA pretreatment delays mPTP opening. Delaying mPTP opening is protective because opening of the mPTP leads to swelling of the mitochondrial matrix, which causes collapse of the inner mitochondrial membrane, uncoupling of the electron transport chain, and release of cytochrome c along with other apoptotic factors such as Bax, caspase-9 and ATP. Administering 5-HD abolished the improved tolerance to calcium-induced mPTP opening. This demonstrates a likely connection between the mPTP and KATP channel.Piriou et al.  noted thAnother pathway that has been identified clinically in cardioprotection is the Akt/PI3k pathway, which is a key intracellular signaling pathway in apoptosis. Raphael et al.  studied The extracellular-signal kinases (ERK) pathway has been linked to myocardial protection elicited by pretreatment with VA. Toma et al.  studied 2+ flux has been linked to cardioprotection via VA pretreatment as well as nuclear factor-κB (NF-κB) involvement. An et al. [2+ concentration by fluorescence and demonstrated that pretreatment with sevoflurane improved coronary blood flow and reduced systolic Ca2+ loading. Further, decreased destruction of sarcoplasmic reticulum Ca2+ − cycling proteins was observed on Western Blot. The reduced systolic Ca2+ leads to the conclusion that this is a cardioprotective effect since reperfusion injury—which leads to irreversible damage—is a result of Ca2+ excess. The accumulation of Ca2+ after ischemia-reperfusion leads to activation of NF-κB, which causes release of inflammatory mediators. Further research demonstrated preservation of calcium cycling proteins following VA pretreatment in a myocardial ischemia-reperfusion model [In addition, Ca et al.  measuredn model . Konia en model  studied While anesthetic pretreatment demonstrates cardioprotection in the laboratory, it is crucial to answer the question whether these cardioprotective effects are also clinically applicable. Cardiac surgery is a suitable model for studying VA pretreatment, however the administration of other anesthetics during the cardiac surgery may also provide protection, leading to difficulty of clearly answering the question of whether VA are cardioprotective clinically. Clinical trials have evaluated VA pretreatment on patients undergoing cardiac surgery - especially CABG, some of which support a beneficial effect of VA for decreasing myocardial infarction, troponin release, hospital length of stay and death ,89,90.FoATP channel activity in human tissue. By providing a dose of 5-HD to cells it was demonstrated that modulation of the mitochondrial KATP channel is involved in human as well as animal cardiomyocytes during ischemic injury. Administration of 5-HD reduced mitochondrial KATP channel activity in the treatment group. In another group, isoflurane increased mitochondrial KATP channel activity and increased peak current beyond that of the control group demonstrating the role of KATP channel in VA pretreatment clinically. Further clinical studies have shown that ROS are involved in cardioprotection from anesthetic pretreatment; therefore, they investigated the effects of exogenous hydrogen peroxide (H2O2) in their apparatus. First, a cluster of mitochondrial KATP channels were suppressed by ATP administration, next H2O2 was given which resulted in a reactivation of the KATP channels despite the continued presence of ATP indicating that ROS influences KATP channels in human myocardium, in vitro.Several studies have used human cardiac tissue to examine the benefits of VA pretreatment as well as to identify similar mechanistic pathways involved to those elicited in animal studies. Some key mechanistic pathways have been examined using drugs that antagonize ion channels and pathways involved in anesthesia pretreatment. Jiang et al.  used humin vitro study using right atrial appendages obtained from adult patients undergoing cardiac surgery, Mio et al. [ATP channels are involved in cardioprotection from pretreatment with volatile anesthetics, as their results demonstrated isoflurane decreased stress-induced cell death and maintained mitochondrial function. Isoflurane preserved mitochondrial oxygen consumption which was initiated by pyruvate-malate and accelerated by adenosine diphosphate (ADP). Preservation of mitochondrial oxygen consumption indicates a cardioprotective effect from isoflurane. In addition, they noted that isoflurane was protective via the sarcolemmal KATP mechanism. Administration of HMR-1098 diminished the cardioprotective effect of isoflurane from a cell death percentage of 21% (without HMR-1098) to a cell death percentage of 41% with HMR-1098 indicating the involvement of KATP channel clinically.In an  et al.  exploredin vitro human right atrial trabeculae. Recovery of force of contraction was studied in each experimental group: control, sevoflurane pretreatment, and desflurane pretreatment. Force of contraction recovery was significantly improved in the sevoflurane group (from 53% to 85%) and in the desflurane group (from 53% to 86%). Treatment with MPG (ROS scavenger) prevented the force of contraction recovery: in the desflurane + MPG group, force of contraction changed from 53% to 48% and in the sevoflurane + MPG group force of contraction changed from 53% to 56% (both the same as control). Since the administration of MPG abolished recovery in both the desflurane and sevoflurane groups, they concluded that ROS must play a role in the cardioprotective mechanisms triggered by VA pretreatment. The mechanistic pathways of cardioprotection in human tissue has been evaluated through in vitro studies, however further in vivo studies are necessary to definitively establish VA pretreatment as a treatment option for cardioprotection in patients at-risk for myocardial ischemia.Hanouz et al.  studied torsades de pointes, which may lead to ventricular fibrillation [All VA have clinically relevant myocardial depressant effects when given in usual anesthetic concentrations . These ellation ,107 as hllation -110. Desllation ,112. Furllation . Other sllation ,26,113. llation -116. HowZangrillo et al.  recentlyAbounding evidence has shown that pretreatment with volatile anesthetics protects against ischemia/reperfusion injury in both animal and clinical studies. Future investigations need to evaluate the most optimal anesthetic agent, concentration and administration protocol for the best cardioprotective benefits of pretreatment, as studies have noted that there is a difference in cardioprotection dependent upon pretreatment protocol with VA . AdditioWe conclude the results of laboratory studies provide mechanistic pathways supporting the cardioprotective effect of pretreatment with VA. Our opinion is these effects should be beneficial to patients with ischemic cardiac disease who are undergoing surgery. However, the optimum dose and timing of VA administration for this effect must be further investigated. It is reasonable to use greater caution when administering VA for cardiac protection to patients in whom preoperative hemodynamic conditions or cardiac rhythm would magnify the known side effects of VA .ATP) channel; mPTP: Mitochondrial permeability transition pore; ROS: Reactive oxygen species; VA: Volatile anesthetics; O2: Oxygen; ATP: Adenosine triphosphate; PKC: Protein kinase C; TK: Tyrosine kinase; FoC: Recovery of force of contraction; MI: Myocardial infarction; ERK: Extracellular-signal kinases (ERK) pathway; NF-κB: Nuclear factor-κB; CABG: Coronary Artery Bypass Graft; H2O2: Hydrogen peroxide; ADP: Adenosine diphosphate; ECG: Electrocardiogram.ATP: Adenosine triphosphate -sensitive K + (KThe authors declare they have no competing interests.NV-Role included reviewing manuscripts, review design, and manuscript preparation. PK-Role included review design and manuscript editing. AL-Role included literature search, review design and proof reading. RA-Role included editing and manuscript preparation. JT-Role included manuscript proof reading. JZ-Role included review design and manuscript proof reading. All authors read and approved the final manuscript.


Resolution of inflammation is a coordinated and active process aimed at restoration of tissue integrity and function. This review integrates the key molecular and cellular mechanisms of resolution. We describe how abrogation of chemokine signalling blocks continued neutrophil tissue infiltration and how apoptotic neutrophils attract monocytes and macrophages to induce their clearance. Uptake of apoptotic neutrophils by macrophages reprograms macrophages towards a resolving phenotype, a key event to restore tissue homeostasis. Finally, we highlight the therapeutic potential that derives from understanding the mechanisms of resolution. Inflammation is a pathophysiological response to infection or tissue damage. In order to neutralize the causing agent, the innate immune system launches a program that unfolds in several phases  is attained. In this review we highlight the essential mechanisms underlying resolution of inflammation and discuss how these mechanisms can be targeted to accelerate return to tissue integrity.The past few years have witnessed an appreciation of the complex resolution of inflammation process, characterized by molecular and cellular events that ultimately assure tissue repair and regain of physiological function. A crucial point is the concept that resolution is an active phenomenon, aimed at actively suppressing and extinguishing a vibrant inflammatory reaction once its main objective  or iron saturation state (e.g. lactoferrin).Intriguingly, apoptotic neutrophils may attenuate inflammation through distinct mechanisms. Dying neutrophils secrete mediators that inhibit further neutrophil recruitment. One is annexin A1 , a protein abundant in the cytosol of resting neutrophils. AnxA1 translocates to the plasma membrane when activated, where it interacts with the formyl peptide receptor 2 (FPR2/ALX) to moderate leukocyte adhesion and migration , sphingosine 1-phosphate (S1P), fractalkine (CX3CL1), and the nucleotides ATP and UTP  inhibits neutrophil entry to tissue sites while promoting monocyte migration  cells  are candidates for cellular therapies aimed at promoting tissue repair or immunoregulation  and T systems .Reg, a subset of CD4+CD25+ T lymphocytes that co-express the transcription factor Foxp3 —removal of apoptotic neutrophils is of dual importance: it induces reprogramming of macrophages and prevents spilling of potentially toxic contents from the neutrophil cytoplasm as they become necrotic.Induction of neutrophil Egress of immune cells—following efferocytosis, macrophages and dendritic cells leave the site of inflammation.immune response—instruction of suppressive immune cells and the adaptive immune response to help dealing with subsequent encounters.Positive modulation of the repair—return to homeostasis without fibrosis or scar formation marks the final step of resolution.Induction of tissue Resolution, the return to normal inflammatory conditions, does not merely consist in catabolism of inflammatory mediators and abrogation of inflammatory processes. Instead, resolution is an active and coordinated anti-inflammatory, pro-resolving programme aimed at restoration of tissue homeostasis, integrity and function. Pro-resolving mediators should ideally fulfill the following criteria:i.e. from antagonism to agonism. The advantage of immunoresolvents would be to limit continued neutrophil infiltration, counter-regulate pro-inflammatory mediators, enhance the containment and phagocytosis of cellular debris and apoptotic neutrophils, and promote restoration of tissue homeostasis  for the cell remnants perpetuates inflammation. AnxA1, resolvins and LXA4 were all shown to induce efferocytosis, which partially explains their resolution-inducing activities in vivo  and a synthetic analogue (RX-100045) are being tested in numerous inflammatory diseases including dry eye, retinal disease, asthma, inflammatory bowel diseases, rheumatic arthritis and cardiovascular diseases. RX-100045 has successfully completed the phase II study in dry eye patients and is scheduled to enter a phase III randomized, placebo-controlled, multi-centre study Lee, . In anotOur understanding of resolution as an active process has come a long way since the early observations by Elie Metchnikoff who observed that neutrophils are phagocytosed by macrophages and how this clearance resolves tissue inflammation (Mechnikov,


Premature discontinuation of aromatase inhibitors (AIs) in breast cancer survivors compromises treatment outcomes. We aimed to evaluate whether patient-reported joint pain predicts premature discontinuation of AIs.We conducted a retrospective cohort study of postmenopausal women with breast cancer on AIs who had completed a survey about their symptom experience on AIs with specific measurements of joint pain. The primary outcome was premature discontinuation of AIs, defined as stopping the medication prior to the end of prescribed therapy. Multivariate Cox regression modeling was used to identify predictors of premature discontinuation.P = 0.016) and prior use of tamoxifen  were significant predictors of premature discontinuation of AIs. The most common reason for premature discontinuation was joint pain (57%) followed by other therapy-related side effects (30%). While providers documented joint pain in charts for 82% of patients with clinically important pain, no quantitative pain assessments were noted, and only 43% provided any plan for pain evaluation or management.Among 437 patients who met eligibility criteria, 47 (11%) prematurely discontinued AIs an average of 29 months after initiation of therapy. In multivariate analyses, patient-reported worst joint pain score of 4 or greater on the Brief Pain Inventory (BPI) (Hazard Ratio [HR] 2.09, 95% Confidence Interval [CI] 1.14-3.80, Worst joint pain of 4 or greater on the BPI predicts premature discontinuation of AI therapy. Clinicians should monitor pain severity with quantitative assessments and provide timely management to promote optimal adherence to AIs. Third-generation aromatase inhibitors (AIs) are commonly prescribed as standard adjuvant therapy for postmenopausal breast cancer survivors with hormone-receptor positive disease and are associated with improved disease-free survival compared with the previous standard of tamoxifen therapy-4. The rDespite the survival benefits of AIs, many women demonstrate some degree of non-adherence with their use. Non-adherence, a term which comprises both non-compliance with dosing, timing, and instruction of medication and non-persistence, or early discontinuation of medication, represents an emergent area to intervene for treatment benefit. Indeed, non-adherence of adjuvant endocrine therapy has been associated with increased mortality in breast cancer patients. In the Despite the prevalence of early medication discontinuation and its deleterious effects, little is understood about risk factors for premature discontinuation of AI therapy. The available adherence research largely consists of medical claims-based epidemiological studies in which younger age, increased cormorbidities, and higher medication co-payments have been noted as risk factors for nonadherence to adjuvant therapy-12. WhilParticipants were identified from the Wellness after Breast Cancer (WABC) study, an ongoing cohort study of breast cancer patients who completed a survey at the time of recruitment between March 2008 and July 2009 at the University of Pennsylvania . The incPremature discontinuation of AIs, defined as stopping medication prior to the end of prescribed therapy, was determined by chart review of outpatient electronic medical records (EMR). Medication events were evaluated from the survey date to December 2011 (follow-up period of 29–45 months). Each oncology visit progress note was reviewed for information concerning the prescribed AI and planned duration of therapy at the time of prescription. Patients varied in their duration of therapy depending on whether an AI was incorporated as primary, sequential, or extended adjuvant endocrine therapy and we deferred to the provider-determined end date for all patients as documented in the EMR[et al.[N=5), death (N=8), or loss to follow up from the outpatient clinic (N=20).We regarded premature discontinuation as an intentional action of the patient in line with the definition of non-persistence presented by Guth et al.. Disconta priori dichotomized patients into two groups: those reporting joint pain severity from 0–3 and those reporting joint pain from 4–10, a level at which pain becomes clinically important and interferes with daily functioning[Patient-reported pain outcomes were obtained from the one time baseline survey that established the cohort. To evaluate clinically important joint pain, we used the worst pain measure from the Brief Pain Inventory (BPI) with slight modifications. Particictioning. To evalctioning.Self-reported demographic variables included age, race/ethnicity, education level, date of last menstrual period (LMP), and reasons for menopause . Comorbidities were assessed using a standard checklist and categorized into 0, 1, or 2, or more conditions. Clinical variables such as tumor type, stage, treatment regimen, and treatment status were collected via medical chart abstraction.Provider encounter notes in the EMR on the date each subject completed the initial WABC survey were reviewed to compare provider and patient reports of joint pain. We analyzed the visit note for documentation of joint pain and, if present, indications of the level of joint pain using quantitative pain ratings and whether a plan to address joint pain was provided.P <0.10) and premature AI discontinuation. All statistics were two-sided with P <0.05 indicating significance.Data analysis was conducted using STATA 12 for Windows . Survival analyses were performed using the Kaplan-Meier method to examine individual predictors of premature discontinuation from the time of initial survey. Multivariate Cox proportional hazards regression models were used to estimate the association between predictive variables  were taking an AI at survey date. Twenty-four subjects (4.8%) were excluded after chart review revealed metastatic disease at the time of enrollment, leaving a total of 437 eligible patients  had completed their course of AI therapy for the full duration prescribed, while 193 (44%) continued to take an AI. Forty-seven women (11%) prematurely discontinued their course of AI therapy after an average of 29.4 ± 18.2 months . Higher education level (P = 0.071) and prior use of tamoxifen (P = 0.088) were also associated with early discontinuation but did not reach statistical significance (Table P = 0.016) .In univariate analyses, patient-reported joint pain severity ≥4 (measured at cohort entry) was significantly associated with premature discontinuation of AI therapy . Provider  documentation of joint pain was noted in 124 visits (82%), however, no quantitative assessments of pain were observed. Providers documented a plan for joint pain  in 43% of visits.We restricted our analysis of provider behavior to include only individuals reporting clinically important pain (worst joint pain rating 4–10) on the initial survey (In this retrospective analysis we evaluated whether patient-reported joint pain severity is predictive of premature discontinuation of AIs. After controlling for demographic and clinical characteristics, patients who reported worst joint pain severity of 4 or greater on the BPI were significantly more likely to prematurely discontinue AI therapy. However, patient-reported AIAA did not predict premature discontinuation. Although clinicians often documented the presence of joint pain in the EMR of patients with clinically important pain, no quantitative assessment was used, and only half offered a plan to further evaluate or treat pain. These findings warrant future clinical improvements in both pain diagnosis and management for breast cancer survivors receiving AI therapy.Premature discontinuation specific to AI therapy has been reported to range from 13-35% in the emerging literature-9. Theseet al. demonstrated an absolute increase in mortality of more than 7% in women who prematurely discontinued hormonal therapy with either an AI or tamoxifen compared to those who continued therapy over a 4.5 year period. Even with adjustment for relevant clinical and demographic variables, early discontinuation was associated with a relative 26% increase in all-cause mortality[Premature discontinuation, as one aspect of non-adherence, has substantial negative effects by the very meaning of its definition – the complete cessation of therapy. Hershman We found patient-reported worst joint pain severity of 4 or greater to be predictive of premature AI discontinuation. Interestingly, patient-reported AI-associated arthralgia was not a significant predictor, suggesting that it is the severity of joint pain, rather than its assumed origins, that may lead women to stop therapy. The finding of joint pain severity as a predictor of premature discontinuation is consistent with a recently published study in a clinical trial setting in which higher baseline pain is a positive predictor of early discontinuation of AI therapy. These fIn contrast to research suggesting physicians' failure to routinely assess patient pain, it is eIn multivariate modeling, we found that controlling for joint pain severity strengthened the association between prior tamoxifen use and premature discontinuation of AIs. This suggests that for patients who experience the same level of pain severity, they are more likely to discontinue AIs if they had prior use of tamoxifen. Based on clinical experience, it is possible that prior tamoxifen users who perceived that they had adequate hormonal therapy were therefore less tolerant of side effects of AIs. Another possible explanation is that prior tamoxifen users have gotten used to the side effects of tamoxifen over time and when they experience new side effects related to AIs, they prefer to switch back to tamoxifen rather than staying on AIs.Our study has several potential limitations. First, in our retrospective cohort study design, we assessed joint pain one time to predict premature discontinuation of AIs. As pain may change over time, our data does not provide an absolute cut-off pain level necessary to discontinue AIs and requires validation in independent datasets. Additionally, our retrospective design did not include patients who prematurely discontinued AIs prior to enrollment which may bias our results towards null. Thus, the strength of association between joint pain severity and premature discontinuation may in fact be even stronger. Third, our outcome focused on premature discontinuation based on chart-abstraction. Theoretically, patients may discontinue therapy without informing their providers; however, if that is the case, it should bias our results towards null. Lastly, our research was conducted in a large academic medical center which may limit the ability to generalize findings to community hospital settings.Despite these limitations, our study had a number of strengths including a large clinical population, incorporation of patient-reported outcome, and examination of provider pain diagnosis and management behaviors. We found that patient-reported joint pain severity of 4 or greater was significantly associated with early discontinuation of therapy. These results highlight the importance of medical providers performing quantitative assessments of pain and inquiring about other medication adverse effects in order to appropriately identify patients who may be at risk for stopping therapy. Targeting interventions for these patients will ultimately optimize adherence to AIs and improve both quality of life and survival outcomes for women with breast cancer.Written informed consent was obtained from each participant.RG has served on a Pfizer Data and Safety Monitoring Board for a drug unrelated to the treatment of breast cancer. JTF has consulted with Pfizer and AstraZeneca on design of clinical trials of pain therapeutics that are unrelated to aromatase inhibitors. AD has consulted and received research grants from Pfizer in the area of breast cancer. JM has consulted with Pfizer on pain medication unrelated to aromatase inhibitors or breast cancer.KC designed the study, collected data come and drafted the manuscript. SX designed and performed statistical analyses. QSL performed statistical analyses and drafted the manuscript. CS, RG, JF, and AD participated in study design, assisted in data interpretation, and helped to draft the manuscript. JJM designed the study, drafted the manuscript, and obtained funding. All authors read and approved the final manuscript.The pre-publication history for this paper can be accessed here:http://www.biomedcentral.com/1471-2407/13/401/prepub