bluuebunny/crossref_metadata_2025_split huggingface dataset:
Is reproductive allocation inSenecio vulgarisplastic?
Authors: Weiner Jacob , Rosenmeier Lars , Massoni Emma Soy , Vera Josep Nogués , Plaza Eva Hernández , Sebastià Maria-Teresa 
Published: May 2009

Several purported cases of plasticity in plant allocation patterns appear to be the effects of size and allometric growth (“apparent plasticity”). To ask whether there is true plasticity (i.e., a change in the allometric trajectory) in reproductive allocation in Senecio vulgaris L., we grew S. vulgaris plants at high and low levels of water, nutrients, and competition, and analyzed the relationship between vegetative and seed biomass. Plant size was the major determinant of reproductive output, accounting for 83% of the variation in log (seed mass). There were also significant effects of the treatments that were not due to size, accounting for an additional 9% of the variation. The treatments affected the allometric coefficient (intercept), not the allometric exponent (slope) of the relationship, reflecting a small but significant shift in the efficiency of conversion of total plant biomass into reproductive biomass. In a second experiment, we grew S. vulgaris plants at three nutrient levels and allowed all individuals to complete their life cycles. Again, nutrient level had a small but significant effect on the allometric coefficient. Plasticity in reproductive allocation exists, but is very limited. The primary effects of the environment on the reproductive output of S. vulgaris occur via plant size.
Aerial and detritus production of the cordgrass Spartina densiflora in a southwestern Atlantic salt marsh
Authors: Vera Federico , Gutiérrez Jorge L. , Ribeiro Pablo D. 
Published: May 2009

We used a nondestructive method to estimate aerial and detritus productivity of the cordgrass Spartina densiflora Brongn. and evaluated the relative contribution of newly emerged and preexisting tillers to net aerial biomass and detritus production, the relative contribution of tiller detachment and leaf shedding to detritus production, and the incidence of crab ( Neohelice ( Chasmagnathus ) granulata (Dana, 1851)), herbivory in relation to tiller age and its implications for tiller survival. Estimates of aerial and detritus productivity varied between 706.72 (SD = 153.38) and 786.15 (SD = 162.75) g·m–2·year–1 and between 1054.23 (SD = 224.49) and 1223.17 (SD = 246.84) g·m–2·year–1, respectively. These estimates of aerial production are far below the higher productivity estimates known for species of the genus Spartina but within the range of values obtained with nondestructive methods (i.e., 300–1500 g·m–2·year–1). Detachment of standing-dead tillers and leaf shedding contributed virtually in equal quantities to detritus production (i.e., 52% and 48% of the total detritus biomass, respectively). On the other hand, net aerial biomass production was highly dependent on tiller recruitment, with 67% of total biomass production contributed by the growth of tillers that emerged during the course of the study. However, crabs seem to graze on tillers irrespective of their age. Such nonselective crab grazing on tillers of different age together with the long tiller survival after crab grazing (often more than a year) suggests that crabs do not ostensibly affect S. densiflora production.
Reproductive development and seed ripening inBetula papyriferaalong an altitudinal thermal gradient in eastern Appalachia (Canada)
Authors: Grenier Marianne , Sirois Luc 
Published: May 2009

In several gymnosperm tree species of the circumboreal forest, reproductive development is closely associated with the accumulation of degree-days during the growing season. We wanted to verify whether this pattern holds for a widespread angiosperm species such as paper birch ( Betula papyrifera Marsh), a broadleaf tree distributed throughout the North American boreal forest. Stations to simultaneously measure the thermal sum (degree-days > 5 °C, DD) and the reproductive development (anatomical development and seed germination) were installed in four sites along an altitudinal thermal gradient totalling 541 m a.s.l. in the eastern Appalachian Mountains (Canada). In 2004, sites 1, 2, 3 and 4, received 973, 1099, 1266 and 1359 DD, respectively. A strong relationship was found between thermal sum and reproductive development (anatomical development: r2 > 0.90; seed germination r2 > 0.72). This relationship seems to be based on the absolute value of heat-sum received because (i) rates of reproductive development are twice as high in colder sites (1 and 2) than in warmer sites (3 and 4), and (ii) total seed germination did not differ among the sites. Along with this, we noted a lesser production of full seeds in colder sites, coupled with a higher success of germination in the coldest site (site 1), which appears to be a mechanism of phenotypic adaptation to cold.
Effects of shading on photosynthesis, plant organic nitrogen uptake, and root fungal colonization in a subarctic mire ecosystem
Authors: Olsrud Maria , Michelsen Anders 
Published: May 2009

Arctic dwarf shrub ecosystems are predicted to be exposed to lower light intensity in a changing climate where mountain birch forests are expanding. We investigated how shading at 0%, 65%, and 97% affects photosynthesis, organic N uptake, C and N allocation patterns in plants, and root fungal colonization in an ericoid dwarf shrub ecosystem. The ecosystem was labeled by injection of [2-13C,15N]glycine into the soil, and the uptake of 15N and 13C in roots and leaves 24 h later was analysed. Fungal colonization in hair roots was determined visually. Hair root 13C:15N ratios showed that dwarf shrub ecosystems are capable of taking up organic N as intact glycine both under high irradiance levels and under shaded conditions when photosynthesis is strongly reduced. The allocation of 15N to green leaves of Rubus chamaemorus L. increased with shading, whereas the allocation of 13C to leaves of both deciduous and evergreen plant species decreased. Species dominance was correlated with uptake of 13C, i.e., the most productive species also took up the highest amount of glycine. The ecosystem exhibited a tendency towards lower colonization by ericoid mycorrhizal fungi and dark septate endophytes in hair roots when shaded. Thus, shading has implications for processes central to both C and N cycling in subarctic ecosystems. This should be considered in projections of ecosystem responses to climate change and expanding mountain birch forests.
Evaluation of tree canopy epiphytes and bark characteristics associated with the presence of corticolous myxomycetes
Authors: Everhart Sydney E. , Ely Joseph S. , Keller Harold W. 
Published: May 2009

Certain species of myxomycetes (plasmodial slime molds) are regularly present with mosses, lichens, and algae. Corticolous myxomycetes were previously studied in the tree canopy, and observations suggested that species occurrence is patchy and species abundance may increase with the presence of bryophytes and lichens. The purpose of this study was to quantify the association of corticolous myxomycete species with percent cover of epiphytes and with bark characteristics, such as water absorption, bark thickness, and bark pH. Study sites were located in three temperate forests in the southeastern USA. The doubled rope climbing method was used to collect bark from trees and grapevines in a vertical transect up to 15 m above ground level. Moist chambers (374) were used to culture myxomycetes for 32 d. The percent cover of lichens, bryophytes, myxobacteria, and filamentous fungi were estimated in five 2 cm × 2 cm quadrats for 187 sample sites. Results showed no association between percent cover of epiphytes and myxomycetes. Bark pH was the major factor influencing the occurrence of corticolous myxomycete species, and the patchy distribution of myxomycetes was attributed to the small plasmodium characteristic of most corticolous species.
Inhibition by fibrates of plasminogen activator inhibitor type-1 expression in human adipocytes and preadipocytes
Authors: Ernst Sandra , Leugers Anne , Willecke Florian , Sobel Burton , Bode Christoph , Nordt Thomas , Zirlik Andreas 
Published: May 2009

SummaryPlasminogen activator inhibitor type-1 (PAI-1), an established marker and mediator of cardiovascular risk, is produced extensively in adipose tissue. Fibrates are hypolipidemic peroxisome proliferator activated receptor-alpha (PPARα) agonists. Recent laboratory and clinical observations indicate that they are also anti-atherosclerotic. Mechanisms responsible, however, remain to be fully understood. The present study was designed to elucidate modulation of PAI-1 expression in adipose cells by fibrates as a potential mechanism. Expression of PPARα was verified by PCR, immunohistochemistry, and Western blotting. In cultured preadipocytes and adipocytes gemfibrozil and fenofibrate significantly reduced PAI-1 protein expression by up to 55 ± 5% and 34 ± 4% under basal conditions and up to 56 ± 6% and 31 ± 6% under conditions of stimulation of the cells with 40 pM trans-Keywords forming growth factor (TGF)β, respectively. Quantification of mRNA showed that the gemfibrozil-induced effect was at least in part regulated at the transcriptional level. Incubations with non-fibrate PPARα agonists showed similar reductions in PAI-1 expression. The decrease in PAI-1 expression induced by gemfibrozil was inhibited by MK886, a PPARα inhibitor. Furthermore, preadipocytes isolated from PPARα-deficient mice produced significantly more PAI-1 than those from wild-type mice upon stimulation with TGFβ. Finally, fenofibrate reduced PAI-1 expression both in plasma and adipose tissue of hyperlipidemic mice. Our data support the view that PPARα activation down-regulates PAI-expression in adipose cells that may contribute in part to the reduction in cardiovascular mortality seen with fibrates in clinical trials.
Peripheral arterial disease and Virchow’s triad
Authors: Bennett Philip , Silverman Stanley , Gill Paramjit , Lip Gregory 
Published: May 2009

SummaryPeripheral arterial disease (PAD) is an important global health-care problem associated with considerable morbidity and mortality. This disease is an important manifestation of atherosclerosis and the pathophysiological processes involved in its development, progression and complications are atherothrombosis and thromboembolism. Over 150 years ago, Virchow described a triad of abnormalities (abnormal blood flow, abnormal vessel wall and abnormal blood constituents) associated with thrombus formation (thrombogenesis). An improvement in biochemical techniques has allowed quantification of various components of Virchow’s triad, and as a consequence, there has been increasing interest in the measurement of such biomarkers in understanding the development and progression of PAD, as well as its symptomatic complications. This review discusses quantifiable components of Virchow’s triad that have been associated with PAD and their clinical utility as risk factors for PAD.
Angiostasis as a way to improve immunotherapy
Authors: Vyth-Dreese Florry , Griffioen Arjan 
Published: May 2009

SummaryTumours express tumour-associated antigens that are recognised as self-antigens precluding the induction of effective anti-tumour immune responses. Inflammatory conditions which facilitate appropriate antigen presentation and reduce the immuno-suppressive micro-milieu may break tolerance. However, tumours have evolved mechanisms to escape cytotoxic T-cell attack by expressing inhibitory molecules on their surface, secreting suppressive factors, attracting regulatory T cells to the tumour environment or downregulating MHC molecules. Induction of angiogenesis by tumours may represent another mechanism by which tumours escape from immune attack. It provides an anti-inflammatory milieu that will prevent appropriate activation and maturation of antigen presenting cells, allow tumours to secrete suppressive factors and inhibit expression of tumour endothelial adhesion receptors, such as intercellular adhesion molecule-1, vascular cell adhesion molecule-1 and E-selectin, needed for appropriate interactions with immune cells. Inhibition of angiogenesis may, apart from its direct detrimental effects on the tumour, reverse these processes and contribute to anti-tumour immune reactivity. Without trying to give a complete overview of the field, this paper reviews insights on angio-genesis inhibition in relation to tumour immune responsiveness, mainly based on the Maastricht-Amsterdam experience. This review adds to the hypothesis of improvement of immuno-directed therapies for cancer by angiostasis.
Ankle exercise and venous blood velocity
Authors: Yaekoub Abdo , Ahsan Syed , Matta Fadi , Lala Monisha , Mirza Bakhtiar , Badshah Aaref , Zamlut Mahmud , Malloy Dennis , Denier James , Stein Paul 
Published: May 2009

SummaryAnkle exercise increases venous blood velocity while supine, but the effect of ankle exercise on venous blood velocity while sitting is not known. In this investigation, we test the hypothesis that venous blood velocity can be increased while sitting by repetitive dorsiflexion of the foot. Time-averaged peak velocity (TAPV) in the popliteal vein of 20 healthy male volunteers was measured by pulsed Doppler ultrasound at rest and during ankle exercise in the supine and sitting positions. Right popliteal vein TAPV while supine at rest was 11 cm/second (sec) (95% confidence interval [CI] =9–13 cm/sec) and with ankle exercise it increased to 24 cm/sec (95% CI =20–28 cm/sec) (p<0.0001). With sitting at rest, right popliteal vein blood TAPV decreased from 11 cm/sec to 3 cm/sec (95% CI = 2–4 cm/sec) (p<0.0001). With ankle exercise while sitting, right popliteal vein TAPV increased to 18 cm/sec (95% CI =15–21 cm/sec) (p<0.0001). In conclusion, in both the supine and sitting positions, ankle exercise increased venous blood velocity, thereby transiently reducing a tendency toward venous stasis. Such ankle exercise might be useful in the prevention of stasis-induced deep venous thrombosis.
Haemoglobin blocks von Willebrand factor proteolysis by ADAMTS-13: A mechanism associated with sickle cell disease
Authors: Zhou Zhou , Han Hyojeong , Cruz Miguel , López José , Dong Jing-Fei , Guchhait Prasenjit 
Published: May 2009

SummaryVascular occlusion, thromboembolism and strokes are hallmark events in sickle cell disease (SCD). The von Willebrand factor (VWF), largest adhesive protein in circulation, has been implicated as major component in these processes. In SCD, a high level of extracellular haemoglobin (Hb) in plasma has been shown parallely associated with the disease pathogenesis. Investigating the effect of Hb we observed that purified Hb significantly inhibited the ADAMTS-13 cleavage of VWF under static and flow conditions. Hb bound potently to VWF specifically VWFA2 in a saturation-dependent manner with half-maximal binding 24 nM. Inversely, VWFA2 also bound potently to Hb and binding was inhibited by VP1 antibody, which binds to ADAMTS-13 cleavage site on VWF. Microscopic observation also shows that Hb bound specifically to endothelial VWF under flow. Furthermore, the Hb-bound VWF multimers were isolated from plasma. Though, Hb bound also to ADAMTS-13, it is the Hb binding to VWFA2 that prevented the substrate being cleaved by ADAMTS-13. In an observation in a small pool of patients with SCD, high Hb in plasma was inversely correlated with low proteolytic activity of ADAMTS-13. Thus, the observations suggest that the patients with SCD suffer from an acquired ADAMTS-13 deficiency primarily because Hb competitively bound and blocked the proteolysis of VWF, leading to the accumulation of ultra-large VWF multimers in circulation and on endothelium. Therefore, the Hb-VWF interaction may be considered as a therapeutic target for treating thrombotic and vaso-occlusive complications in patients with severe intravascular haemolysis such as those with SCD.
Role of viral receptors TLR3, RIG-I and MDA5 in mesothelial tissue-type plasminogen activator and plasminogen activator inhibitor-1 synthesis
Authors: Sauter Matthias , Kastenmüller Kathrin , Ribeiro Andrea , Mussack Thomas , Ladurner Roland , Sitter Thomas , Wörnle Markus 
Published: May 2009

SummaryTissue-type plasminogen activator (t-PA) and its specific inhibitor plasminogen activator inhibitor-1 (PAI-1) are key mediators in the regulation of fibrin generation and fibrinolysis. Mesothelial cells (MC) line the inner surface of serosal cavities and are a source of procoagulant and fibrinolytic system components. Viral inflammation and infection of MC are a major problem in several organ systems including pleura, pericardium and peritoneum. MC express the viral receptors Toll-like receptor 3 (TLR3), RIG-I and MDA5. TLRs recognise molecular patterns associated with microbial pathogens and induce an immune response. TLR3 recognises dsRNA of viral origin as exemplified by poly (I:C) RNA, a synthetic analogue of viral dsRNA. The helicases RIG-I and MDA5 may also act as sensors of viral infections. Activation of these receptors by poly (I:C) RNA leads to an time- and dose-dependent increase of mesothelial PAI-1 synthesis and a decrease of t-PA expression. To show the specific effect of viral receptors knockdown experiments with siRNA specific for TLR3, RIG-I and MDA5 were performed. This finding of viral induced changes of t-PA and PAI-1 synthesis may indicate a novel link between viral infections and formation of mesothelial fibrin deposits and progression of viral associated disease of the pleura, peritoneum and pericardium.
Effects of polysaccharides enriched in 2,4-disulfated fucose units on coagulation, thrombosis and bleeding
Authors: Fonseca Roberto , Santos Gustavo , Mourão Paulo 
Published: May 2009

SummarySulfated polysaccharides from marine invertebrates have welldefined structures and constitute a reliable class of molecules for structure-activity relationship studies.We tested the effects of two of these polysaccharides,namely a sulfated fucan and a fucosylated chondroitin sulfate, on coagulation, thrombosis and bleeding. The compounds share similar 2,4-disulfated fucose units, which are required for high anticoagulant activity in this class of polymer.These residues occur either as branches in fucosylated chondroitin sulfate or as components of the linear chain in the sulfated fucan.These polysaccharides possess anticoagulant activity but differ significantly in their mechanisms of action.The fucosylated chondroitin sulfate inhibits thrombin by heparin cofactor II, whereas sulfated fucan inhibits thrombin by both antithrombin and heparin cofactor II. In addition, these polysaccharides also have serpin-independent anticoagulant activities. Fucosylated chondroitin sulfate, but not sulfated fucan, activates factor XII. As a result of the complex anticoagulant mechanism, the invertebrate polysaccharides differ in their effects on experimental thrombosis. For instance, the sulfated fucan inhibits venous thrombosis at lower doses than fucosylated chondroitin sulfate. In contrast, fucosylated chondroitin sulfate is significantly more potent than sulfated fucan in arterial thrombosis. Finally, fucosylated chondroitin sulfate increases bleeding, while sulfated fucan has only a discrete effect. In conclusion, the location of 2,4-disulfated fucose units in the polysaccharide chains dictates the effects on coagulation, thrombosis and bleeding.
Prolactin does not affect human platelet aggregation or secretion
Authors: Nieuwland Rienk , Fernandez Isabelle , Goffin Vincent , van Tiel Claudia , Schaap Marianne , Berckmans René , Kastelein John , Twickler Marcel , Reuwer Anne 
Published: May 2009

SummaryPlatelets play an important role in the development of plaque formation and in the events after rupture of the atherosclerotic plaque, leading to atherothrombosis. Multiple hormones, either in excess or when deficient, are involved in the development of atherothrombotic disease, but, to which extent such hormones affect platelet function, is still controversial. It was the objective of this study to assess the ability of the pituitary hormone prolactin to affect platelet functions. Venous blood was collected from six healthy males. Platelet activation was studied by (i) flow cytometry in whole blood (exposure of P-selectin as a measure of platelet secretion, and binding of PAC-1 as a measure of ligand-binding conformation of αIIbβ3), and by (ii) optical aggregation and whole blood aggregation. All studies were performed without and with exposure to several concentrations of ADP (0.1, 0.5 and 1.0 μM) and prolactin (50 and 1,000 μg/l). The presence of the prolactin receptor was investigated by Western blot and flow cytometry. In response to either 50 or 1,000 μg/l prolactin, no evidence of platelet activation or aggregation was found. In addition, ADP-induced platelet activation or aggregation was not enhanced by prolactin. Finally, prolactin receptors could not be detected on the surface of platelets. The present data indicate that prolactin does not directly modulate platelet function.
The inflammatory response as a target to reduce myocardial ischaemia and reperfusion injury
Authors: Steffens Sabine , Montecucco Fabrizio , Mach François 
Published: May 2009

SummaryAcute myocardial infarction is the leading cause of morbidity and mortality in the adult population of developed and developing nations. Although the prompt restoration of antegrade blood flow in the infarct-related coronary artery is the mean therapy for improving survival, reperfusion itself may cause damage to ischaemic myocardial tissue. This event is well known as “reperfusion injury”. Crucial mediators for cardiac damage in the reperfusion phases are oxidative stress, inflammation and leukocyte infiltration. Already approved and novel therapies might directly reduce these inflammatory processes. Treatments modulating chemokine secretion and activity should be considered as very promising approaches to reduce myocardial reperfusion injury.
Association of anaemia and mortality in patients with acute pulmonary embolism
Authors: Escobar Carlos , Martí David , Díaz Gema , César Jesús , García-Avello Ángel , Sueiro Antonio , Yusen Roger D. , Jiménez David 
Published: May 2009

SummaryThis study aimed to evaluate the relationship between anaemia and pulmonary embolism (PE) prognosis. We analysed a cohort of 764 patients with acute PE referred to a single center for diagnosis and management. Patients were divided into groups by quartiles of haemoglobin (Hb): Hb < 11.7 g/dl; Hb 11.7 to 12.9 g/dl; Hb 13.0 to 14.1 g/dl; Hb > 14.1 g/dl. Patients had a mean Hb of 12.9 g/dl, and values ranged from to 4.3 to 19.5 g/dl. Lower Hb was associated with recent bleeding, an impaired haemodynamic profile and higher creatinine. Patients in the lower Hb quartiles more commonly had female gender (p < 0.001), a diagnosis of cancer (p < 0.001), and an indication for an inferior vena cava (IVC) filter (p < 0.002), compared to patients in the higher Hb quartiles. Patients in higher Hb quartiles had higher survival at three months (75%, 86%, 90% and 91% for lowest to highest quartiles, respectively). On multivariate analysis, adjusting for known PE prognostic factors, low Hb proved to be an independent predictor of mortality (hazard ratio [HR] 1.16, 95% confidence interval [CI] 1.05 to 1.28 for each decrease of 1 g/dl). Hb level remained an independent predictor of all-cause mortality when cancer patients were excluded from the analysis (adjusted HR 0.81; 95% CI, 0.66 to 0.99; p = 0.04). Moreover, patients with anaemia showed a higher risk of fatal PE (unadjusted HR 1.19, 95% CI 1.04 to 1.37). In conclusion, in patients with acute symptomatic PE, anaemia severity is associated with worsened survival.