Identification of platelet function defects by multi-parameter assessment of thrombus formation.

Assays measuring platelet aggregation (thrombus formation) at arterial shear rate mostly use collagen as only platelet-adhesive surface. Here we report a multi-surface and multi-parameter flow assay to characterize thrombus formation in whole blood from healthy subjects and patients with platelet function deficiencies. A systematic comparison is made of 52 adhesive surfaces with components activating the main platelet-adhesive receptors, and of eight output parameters reflecting distinct stages of thrombus formation. Three types of thrombus formation can be identified with a predicted hierarchy of the following receptors: glycoprotein (GP)VI, C-type lectin-like receptor-2 (CLEC-2)>GPIb>α6β1, αIIbβ3>α2β1>CD36, α5β1, αvβ3. Application with patient blood reveals distinct abnormalities in thrombus formation in patients with severe combined immune deficiency, Glanzmann's thrombasthenia, Hermansky-Pudlak syndrome, May-Hegglin anomaly or grey platelet syndrome. We suggest this test may be useful for the diagnosis of patients with suspected bleeding disorders or a pro-thrombotic tendency.

Phospholipid oxidation generates potent anti-inflammatory lipid mediators that mimic structurally related pro-resolving eicosanoids by activating Nrf2.

Exposure of biological membranes to reactive oxygen species creates a complex mixture of distinct oxidized phospholipid (OxPL) species, which contribute to the development of chronic inflammatory diseases and metabolic disorders. While the ability of OxPL to modulate biological processes is increasingly recognized, the nature of the biologically active OxPL species and the molecular mechanisms underlying their signaling remain largely unknown. We have employed a combination of mass spectrometry, synthetic chemistry, and immunobiology approaches to characterize the OxPL generated from the abundant phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphocholine (PAPC) and investigated their bioactivities and signaling pathways in vitro and in vivo. Our study defines epoxycyclopentenones as potent anti-inflammatory lipid mediators that mimic the signaling of endogenous, pro-resolving prostanoids by activating the transcription factor nuclear factor E2-related factor 2 (Nrf2). Using a library of OxPL variants, we identified a synthetic OxPL derivative, which alleviated endotoxin-induced lung injury and inhibited development of pro-inflammatory T helper (Th) 1 cells. These findings provide a molecular basis for the negative regulation of inflammation by lipid peroxidation products and propose a novel class of highly bioactive compounds for the treatment of inflammatory diseases.

Effect of Health Risk Assessment and Counselling on Health Behaviour and Survival in Older People: A Pragmatic Randomised Trial.

BACKGROUND Potentially avoidable risk factors continue to cause unnecessary disability and premature death in older people. Health risk assessment (HRA), a method successfully used in working-age populations, is a promising method for cost-effective health promotion and preventive care in older individuals, but the long-term effects of this approach are unknown. The objective of this study was to evaluate the effects of an innovative approach to HRA and counselling in older individuals for health behaviours, preventive care, and long-term survival. METHODS AND FINDINGS This study was a pragmatic, single-centre randomised controlled clinical trial in community-dwelling individuals aged 65 y or older registered with one of 19 primary care physician (PCP) practices in a mixed rural and urban area in Switzerland. From November 2000 to January 2002, 874 participants were randomly allocated to the intervention and 1,410 to usual care. The intervention consisted of HRA based on self-administered questionnaires and individualised computer-generated feedback reports, combined with nurse and PCP counselling over a 2-y period. Primary outcomes were health behaviours and preventive care use at 2 y and all-cause mortality at 8 y. At baseline, participants in the intervention group had a mean ± standard deviation of 6.9 ± 3.7 risk factors (including unfavourable health behaviours, health and functional impairments, and social risk factors) and 4.3 ± 1.8 deficits in recommended preventive care. At 2 y, favourable health behaviours and use of preventive care were more frequent in the intervention than in the control group (based on z-statistics from generalised estimating equation models). For example, 70% compared to 62% were physically active (odds ratio 1.43, 95% CI 1.16-1.77, p = 0.001), and 66% compared to 59% had influenza vaccinations in the past year (odds ratio 1.35, 95% CI 1.09-1.66, p = 0.005). At 8 y, based on an intention-to-treat analysis, the estimated proportion alive was 77.9% in the intervention and 72.8% in the control group, for an absolute mortality difference of 4.9% (95% CI 1.3%-8.5%, p = 0.009; based on z-test for risk difference). The hazard ratio of death comparing intervention with control was 0.79 (95% CI 0.66-0.94, p = 0.009; based on Wald test from Cox regression model), and the number needed to receive the intervention to prevent one death was 21 (95% CI 12-79). The main limitations of the study include the single-site study design, the use of a brief self-administered questionnaire for 2-y outcome data collection, the unavailability of other long-term outcome data (e.g., functional status, nursing home admissions), and the availability of long-term follow-up data on mortality for analysis only in 2014. CONCLUSIONS This is the first trial to our knowledge demonstrating that a collaborative care model of HRA in community-dwelling older people not only results in better health behaviours and increased use of recommended preventive care interventions, but also improves survival. The intervention tested in our study may serve as a model of how to implement a relatively low-cost but effective programme of disease prevention and health promotion in older individuals. TRIAL REGISTRATION International Standard Randomized Controlled Trial Number: ISRCTN 28458424.

Reduced pro-inflammatory profile of γδT cells in pregnant patients with rheumatoid arthritis

BACKGROUND During pregnancy, many patients with rheumatoid arthritis (RA) experience disease improvement, whereas patients with ankylosing spondylitis often suffer from persistent active disease. Here we investigated whether pregnancy-related changes in disease activity were associated with changes in the proportion and function of γδT cells. METHODS The study population comprised 55 patients with RA, 31 patients with ankylosing spondylitis, and 35 healthy controls. Among these participants, 28 RA patients, 21 ankylosing spondylitis patients, and 23 healthy controls were investigated once before conception when possible, at each trimester of pregnancy, and at 8 weeks postpartum. Data were compared with age-matched non-pregnant patients to obtain disease-related background. In all subjects, peripheral Vδ1 and Vδ2 T cells were analyzed for cell frequencies, the activation marker CD69, the cytotoxicity markers NKG2D and NKG2A, and the intracellular cytokines tumor necrosis factor (TNF)α, interferon (IFN)γ, interleukin (IL)-17 and IL-10. RESULTS Pregnant patients showed a decreased Vδ2/Vδ1 ratio in the third trimester, which resulted from a slightly reduced proportion of Vδ2 cells. Changes in RA disease activity during pregnancy and postpartum were not associated with numerical proportions of γδT cells but with changes of the cell activation marker CD69 on Vδ1 and Vδ2 cells. Only RA patients showed reduced proportions of TNFα-positive Vδ1and Vδ2 cells and IFNγ-positive Vδ2 cells at the third trimester of pregnancy, a finding that was not apparent in the entire population of CD3 T cells. The proportions of IL-17-positive γδT cells and IL-10-positive γδT cells did not differ between pregnant and non-pregnant women of the different groups. CONCLUSIONS Changes of disease activity in pregnant RA patients were associated with functional changes in both γδT cell subsets. This reduced pro-inflammatory profile of γδT cells might contribute to the immunomodulation resulting in pregnancy-induced improvement of RA.

Use of quality assessment tools in systematic reviews was varied and inconsistent

OBJECTIVES To assess the use of quality assessment tools among a cross-section of systematic reviews (SRs) and to further evaluate whether quality was used as a parameter in the decision to include primary studies within subsequent meta-analysis. STUDY DESIGN AND SETTING We searched PubMed for SRs (interventional, observational, and diagnostic) published in Core Clinical Journals between January 1 and March 31, 2014. RESULTS Three hundred nine SRs were identified. Quality assessment was undertaken in 222 (71.8%) with isolated use of the Cochrane risk of bias tool (26.1%, n = 58) and the Newcastle-Ottawa Scale (15.3%, n = 34) most common. A threshold level of primary study quality for subsequent meta-analysis was used in 12.9% (40 of 309) of reviews. Overall, fifty-four combinations of quality assessment tools were identified with a similar preponderance of tools used among observational and interventional reviews. Multiple tools were used in 11.7% (n = 36) of SRs overall. CONCLUSION We found that quality assessment tools were used in a majority of SRs; however, a threshold level of quality for meta-analysis was stipulated in just 12.9% (n = 40). This cross-sectional analysis provides further evidence of the need for more active or intuitive editorial processes to enhance the reporting of SRs.

Buparvaquone is active against Neospora caninum in vitro and in experimentally infected mice.

The naphthoquinone buparvaquone is currently the only drug used against theileriosis. Here, the effects of buparvaquone were investigated in vitro and in an experimental mouse model for Neospora caninum infection. In 4-day proliferation assays, buparvaquone efficiently inhibited N. caninum tachyzoite replication (IC50 = 4.9 nM; IC100 = 100 nM). However, in the long term tachyzoites adapted and resumed proliferation in the presence of 100 nM buparvaquone after 20 days of cultivation. Parasiticidal activity was noted after 9 days of culture in 0.5 µM or 6 days in 1 µM buparvaquone. TEM of N. caninum infected fibroblasts treated with 1 µM buparvaquone showed that the drug acted rather slowly, and ultrastructural changes were evident only after 3-5 days of treatment, including severe alterations in the parasite cytoplasm, changes in the composition of the parasitophorous vacuole matrix and a diminished integrity of the vacuole membrane. Treatment of N. caninum infected mice with buparvaquone (100 mg/kg) either by intraperitoneal injection or gavage prevented neosporosis symptoms in 4 out of 6 mice in the intraperitoneally treated group, and in 6 out of 7 mice in the group receiving oral treatment. In the corresponding controls, all 6 mice injected intraperitoneally with corn oil alone died of acute neosporosis, and 4 out of 6 mice died in the orally treated control group. Assessment of infection intensities in the treatment groups showed that, compared to the drug treated groups, the controls showed a significantly higher parasite load in the lungs while cerebral parasite load was higher in the buparvaquone-treated groups. Thus, although buparvaquone did not eliminate the parasites infecting the CNS, the drug represents an interesting lead with the potential to eliminate, or at least diminish, fetal infection during pregnancy.

Anadromous Rainbow Smelt and Tomcod in Connecticut: Assessment of populations, conservation status, and need for restoration plan

(beginning of rainbow smelt executive summary) Evidence indicates that anadromous rainbow smelt (Osmerus mordax) populations in Connecticut and elsewhere in the northeast United States have severely declined. Several sampling programs have documented declines in Connecticut’s smelt populations over the last three decades (Marcy 1976a, Marcy 1976b, Millstone Environmental Laboratory 2005). Similar declines have also been documented in the Hudson River (ASA Analysis & Communication 2005) and in Massachusetts (personal communication, Brad Chase, MA Division of Marine Fisheries 2004). Recreational and commercial fisheries in the region for this species have virtually ceased (Blake and Smith 1984). The Connecticut Fish Advisory Committee of the Endangered Species Program has recommended that rainbow smelt be listed as threatened in Connecticut, and the National Marine Fisheries Service (2004) has recently listed rainbow smelt as a Federal Species of Concern. The purpose of this project is to develop an environmental history of rainbow smelt in Connecticut and surrounding regions, and document the current status of populations in Connecticut waters. An environmental history that assesses trends in abundance, environmental threats and historical efforts to ameliorate the threats will contribute to regional efforts to conserve these fish. Comprehensive review of the regional literature and trends associated with rainbow smelt has not been undertaken since Kendall (1926). Assessment of current abundance, distribution, areas of critical habitat, and whether the species is presently reproducing in state waters is critical for clarifying conservation status, designing a monitoring program and developing a recovery or enhancement plan, if this appears to be necessary. (beginning of tomcod executive summary) Atlantic tomcod (Microgadus tomcod) are believed to have declined significantly in Connecticut and other estuaries of the Northeast and Middle Atlantic states. Several monitoring programs indicate that the species is scarce and/or declining in the region’s estuaries (Gottschall and Pacileo 2004, Molnar 2004, Millstone Environmental Laboratory 2005, ASA Analysis and Communication 2005). Once-active recreational (NMFS MRFSS 2005, http://www.st.nmfs.gov) and commercial fisheries for this species in Connecticut are now dormant. For the past 10 years, the Connecticut Fish Advisory Committee of the Endangered Species Program has recommended that studies be undertaken to quantify the status of tomcod populations and to determine if conservation actions should be initiated. The purpose of this project is to develop an environmental history of Atlantic tomcod in Connecticut and surrounding regions, and document the current status of populations in Connecticut waters. An environmental history that assesses trends in abundance, environmental threats and historical efforts to ameliorate the threats will contribute to regional efforts to conserve these fish. Assessment of current abundance, distribution, areas of critical habitat, and whether the species is presently reproducing in state waters is critical for determining conservation status, designing a monitoring program and developing a recovery or enhancement plan, if this appears to be necessary.

The association between mental health and cigarette smoking in active duty military members

Previous research has shown an association between mental health status and cigarette smoking. This study examined four specific mental health predictors and the outcome variable any smoking, defined as smoking one or more cigarettes in the past 30 days. The population included active duty military members serving in the United States Army, Air Force, Navy and Marine Corps. The data was collected during the 2005 Department of Defense Survey of Health Related Behaviors Among Active Duty Military Personnel, a component of the Defense Lifestyle Assessment Program. The sample size included 13,603 subjects. This cross sectional prevalence study consisted of descriptive statistics, univariate analysis, and multivariate logistic regression analysis of the four mental health predictors and the any smoking outcome variable. Multivariate adjustment showed an association between the four mental health predictors and any smoking. This association is consistent with previous literature and can help guide public health officials in the development of smoking prevention and cessation programs.^

Air Force Web Preventive Health Assessment (AF WEBPHA) mental health screening effectiveness

The U.S. Air Force assesses Active Duty Air Force (ADAF) health annually using the Air Force Web-based Preventative Health Assessment (AF WebPHA). The assessment is based on a self-administered survey used to determine the overall Air Force health and readiness, as well as, the individual health of each airman. Individual survey responses as well as groups of responses generate further computer generated assessment and result in a classification of 'Critical', 'Priority', or 'Routine', depending on the need and urgency for further evaluation by a health care provider. The importance of the 'Priority' and 'Critical' classifications is to provide timely intervention to prevent or limit unfavorable outcomes that may threaten an airman. Though the USAF has been transitioning from a paper form to the online WebPHA survey for the last three years it was not made mandatory for all airmen until 2009. The survey covers many health aspects including family history, tobacco use, exercise, alcohol use, and mental health. ^ Military stressors such as deployment, change of station, and the trauma of war can aggravate and intensify the common baseline worries experienced by the general population and place airmen at additional risks for mental health concerns and illness. This study assesses the effectiveness of the AF WebPHA mental health screening questions in predicting a mental health disorder diagnosis according to International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) codes generated by physicians or their surrogates. In order to assess the sensitivity, specificity, and positive predictive value of the AF WebPHA as a screening tool for mental health, survey results were compared to ascertain if they generated any mental health disorder related diagnosis for the period from January 1, 2009 to March 31, 2010. ^ Statistical analysis of the AF WebPHA mental health responses when compared with matching ICD-9-CM codes found that the sensitivity for 'Critical' or 'Priority' responses was only 3.4% and that it would correctly predict those who had the selected mental health diagnosis 9% of the time.^

Objective assessment of the built environment and its relationship to physical activity and obesity

The role of physical activity in the promotion of individual and population health has been well documented in research and policy publications. Significant research activities have produced compelling evidence for the support of the positive association between physical activity and improved health. Despite the knowledge about these public health benefits of physical activity, over half of US adults do not engage in physical activity at levels consistent with public health recommendations. Just as physical inactivity is of significant public health concern in the US, the prevalence of obesity (and its attendant co-morbidities) is also increasing among US adults.^ Research suggests racial and ethnic disparities relevant to physical inactivity and obesity in the US. Various studies have shown more favorable outcomes among non-Hispanic whites when compared to other minority groups as far as physical activity and obesity are concerned. The health disparity issue is especially important because Mexican-Americans who are the fastest growing segment of the US population are disproportionately affected by physical inactivity and obesity by a significant margin (when compared to non-Hispanic whites), so addressing the physical inactivity and obesity issues in this group is of significant public health concern. ^ Although the evidence for health benefits of physical activity is substantial, various research questions remain on the potential motivators for engaging in physical activity. One area of emerging interest is the potential role that the built environment may play in facilitating or inhibiting physical activity.^ In this study, based on an ongoing research project of the Department of Epidemiology at the University of Texas M. D. Anderson Cancer Center, we examined the built environment, measured objectively through the use of geographical information systems (GIS), and its association with physical activity and obesity among a cohort of Mexican- Americans living in Harris County, Texas. The overall study hypothesis was that residing in dense and highly connected neighborhoods with mixed land-use is associated with residents’ increased participation in physical activity and lowered prevalence of obesity. We completed the following specific aims: (1) to generate a land-use profile of the study area and create a “walkability index” measure for each block group within the study area; (2) to compare the level of engagement in physical activity between study participants that reside in high walkability index block groups and those from low walkability block groups; (3) to compare the prevalence of obesity between study participants that reside in high walkability index block groups and those from low walkability block groups. ^ We successfully created the walkability index as a form of objective measure of the built environment for portions of Harris County, Texas. We used a variety of spatial and non-spatial dataset to generate the so called walkability index. We are not aware of previous scholastic work of this kind (construction of walkability index) in the Houston area. Our findings from the assessment of relationships among walkability index, physical activity and obesity suggest the following, that: (1) that attempts to convert people to being walkers through health promotion activities may be much easier in high-walkability neighborhoods, and very hard in low-walkability neighborhoods. Therefore, health promotion activities to get people to be active may require supportive environment, walkable in this case, and may not succeed otherwise; and (2) Overall, among individuals with less education, those in the high walkability index areas may be less obese (extreme) than those in the low walkability area. To the extent that this association can be substantiated, we – public health practitioners, urban designers, and policy experts – we may need to start thinking about ways to “retrofit” existing urban forms to conform to more walkable neighborhoods. Also, in this population especially, there may be the need to focus special attention on those with lower educational attainment.^

The epidemiology of left ventricular outflow tract obstruction defects in Texas, 2002-2008: An update and assessment of effect heterogeneity

Left ventricular outflow tract (LVOT) defects are an important group of congenital heart defects (CHDs) because of their associated mortality and long-term complications. LVOT defects include aortic valve stenosis (AVS), coarctation of aorta (CoA), and hypoplastic left heart syndrome (HLHS). Despite their clinical significance, their etiology is not completely understood. Even though the individual component phenotypes (AVS, CoA, and HLHS) may have different etiologies, they are often "lumped" together in epidemiological studies. Though "lumping" of component phenotypes may improve the power to detect associations, it may also lead to ambiguous findings if these defects are etiologically distinct. This is due to potential for effect heterogeneity across component phenotypes. ^ This study had two aims: (1) to identify the association between various risk factors and both the component (i.e., split) and composite (i.e., lumped) LVOT phenotypes, and (2) to assess the effect heterogeneity of risk factors across component phenotypes of LVOT defects. ^ This study was a secondary data analysis. Primary data were obtained from the Texas Birth Defect Registry (TBDR). TBDR uses an active surveillance method to ascertain birth defects in Texas. All cases of non complex LVOT defects which met our inclusion criteria during the period of 2002–2008 were included in the study. The comparison groups included all unaffected live births for the same period (2002–2008). Data from vital statistics were used to evaluate associations. Statistical associations between selected risk factors and LVOT defects was determined by calculating crude and adjusted prevalence ratio using Poisson regression analysis. Effect heterogeneity was evaluated using polytomous logistic regression. ^ There were a total of 2,353 cases of LVOT defects among 2,730,035 live births during the study period. There were a total of 1,311 definite cases of non-complex LVOT defects for analysis after excluding "complex" cardiac cases and cases associated with syndromes (n=168). Among infant characteristics, males were at a significantly higher risk of developing LVOT defects compared to females. Among maternal characteristics, significant associations were seen with maternal age > 40 years (compared to maternal age 20–24 years) and maternal residence in Texas-Mexico border (compared to non-border residence). Among birth characteristics, significant associations were seen with preterm birth and small for gestation age LVOT defects. ^ When evaluating effect heterogeneity, the following variables had significantly different effects among the component LVOT defect phenotypes: infant sex, plurality, maternal age, maternal race/ethnicity, and Texas-Mexico border residence. ^ This study found significant associations between various demographic factors and LVOT defects. While many findings from this study were consistent with results from previous studies, we also identified new factors associated with LVOT defects. Additionally, this study was the first to assess effect heterogeneity across LVOT defect component phenotypes. These findings contribute to a growing body of literature on characteristics associated with LVOT defects. ^

Reading comprehension in nacional and internacional programs of educational assessment

El principal objetivo de este artículo es identificar distintos programas de evaluación educativa, tanto nacionales como internacionales, y describir sus características generales. Asimismo, analiza el modo en que se conceptualiza y evalúa la competencia lectora. Finalmente, este trabajo presenta los resultados que ha obtenido Argentina en esta área. Los programas analizados son: el Programa para la Evaluación Internacional de Alumnos (PISA, Programme for International Student Assessment) , el Segundo Estudio Regional Comparativo y Explicativo (SERCE) y, específicamente en nuestro país, el Operativo Nacional de Evaluación (ONE) y el Programa de Evaluación de la Calidad Educativa de la Provincia de Buenos Aires. Estos diferentes estudios sitúan la importancia de la lectura comprensiva en tanto "competencia para la vida" necesaria para la realización de otros aprendizajes, para el logro de una participación activa en la sociedad y ligada a la posibilidad de proyectar un futuro mejor. Los informes muestran la existencia de diferencias entre los resultados de distintos países y al interior de los mismos. El desarrollo de competencias desiguales aparece como un desafío a nivel nacional e internacional, ya que constituye un importante indicador de la situación crítica en la que se encuentran un número significativo de niños y adolescentes.

Reading comprehension in nacional and internacional programs of educational assessment

El principal objetivo de este artículo es identificar distintos programas de evaluación educativa, tanto nacionales como internacionales, y describir sus características generales. Asimismo, analiza el modo en que se conceptualiza y evalúa la competencia lectora. Finalmente, este trabajo presenta los resultados que ha obtenido Argentina en esta área. Los programas analizados son: el Programa para la Evaluación Internacional de Alumnos (PISA, Programme for International Student Assessment) , el Segundo Estudio Regional Comparativo y Explicativo (SERCE) y, específicamente en nuestro país, el Operativo Nacional de Evaluación (ONE) y el Programa de Evaluación de la Calidad Educativa de la Provincia de Buenos Aires. Estos diferentes estudios sitúan la importancia de la lectura comprensiva en tanto "competencia para la vida" necesaria para la realización de otros aprendizajes, para el logro de una participación activa en la sociedad y ligada a la posibilidad de proyectar un futuro mejor. Los informes muestran la existencia de diferencias entre los resultados de distintos países y al interior de los mismos. El desarrollo de competencias desiguales aparece como un desafío a nivel nacional e internacional, ya que constituye un importante indicador de la situación crítica en la que se encuentran un número significativo de niños y adolescentes.

Reading comprehension in nacional and internacional programs of educational assessment

El principal objetivo de este artículo es identificar distintos programas de evaluación educativa, tanto nacionales como internacionales, y describir sus características generales. Asimismo, analiza el modo en que se conceptualiza y evalúa la competencia lectora. Finalmente, este trabajo presenta los resultados que ha obtenido Argentina en esta área. Los programas analizados son: el Programa para la Evaluación Internacional de Alumnos (PISA, Programme for International Student Assessment) , el Segundo Estudio Regional Comparativo y Explicativo (SERCE) y, específicamente en nuestro país, el Operativo Nacional de Evaluación (ONE) y el Programa de Evaluación de la Calidad Educativa de la Provincia de Buenos Aires. Estos diferentes estudios sitúan la importancia de la lectura comprensiva en tanto "competencia para la vida" necesaria para la realización de otros aprendizajes, para el logro de una participación activa en la sociedad y ligada a la posibilidad de proyectar un futuro mejor. Los informes muestran la existencia de diferencias entre los resultados de distintos países y al interior de los mismos. El desarrollo de competencias desiguales aparece como un desafío a nivel nacional e internacional, ya que constituye un importante indicador de la situación crítica en la que se encuentran un número significativo de niños y adolescentes.

Elevated pCO2 from late summer coastal upwellings in the western Baltic Sea enhances vegetative growth in the brown algae Fucus serratus: a laboratory assessment

The brown algae Fucus serratus is one of the major meadow forming algae of the Western Baltic Sea nearshore ecosystem. At the end of summer, those meadows are exposed to local upwelling suddenly increasing the pCO2 and DIC up to 2500 µatm and 2250 µmol/kg resp., for period of days to weeks. This study investigates the growth response of summer's vegetative Fucus serratus to elevated pCO2 (1350 and 4080 µatm) during a 40 days laboratory incubation. After 10 days, increases of growth rates of 20 % and 47 % of the control were observed in the 1350 and 4080 µatm pCO2 treatments respectively. Beyond 20 days, the growth rates collapsed in all treatments due to nutrients shortage, as demonstrated by high C:N ratios (95:1) and low N tissue content (0.04 % of dry weight). The collapse occurs faster at higher pCO2. On day 30, growth rates were reduced by 40 % and 100 % relative to the control at 1350 and 4080 µatm respectively. These results are consistent with a fertilizing effect of elevated pCO2 on Fucus serratus presumably linked to the transition from active HCO3- to passive CO2(aq) uptake. This positive effect is limited by nutrients resources, low seawater dissolved inorganic N and P and shortage of the nutrients reserves accumulated over the previous autumn and winter.