Characterization of local and systemic immune-modulation in melanoma patients

Le mélanome cutané est un des cancers les plus agressifs et dont l'incidence augmente le plus en Suisse. Une fois métastatique, le pronostic de survie moyenne avec les thérapies actuelles est d'environ huit mois, avec moins de 5% de survie à cinq ans. Les récents progrès effectués dans la compréhension de la biologie de la cellule tumorale mais surtout dans l'importance du système immunitaire dans le contrôle de ce cancer ont permis le développement de nouveaux traitements novateurs et prometteurs. Ces thérapies, appelées immunothérapies, reposent sur la stimulation et l'augmentation de la réponse immunitaire à la tumeur. Alors que les derniers essais cliniques ont démontré l'efficacité de ces traitements chez les patients avec des stades avancés de la maladie, le contrôle de la maladie à long- terme est seulement atteint chez une minorité des patients. La suppression locale et systémique de la réponse immunitaire spécifique anti-tumorale apparaitrait comme une des raisons expliquant la persistance d'un mauvais pronostic clinique chez ces patients. Des études sur les souris ont montré que les vaisseaux lymphatiques joueraient un rôle primordial dans ce processus en induisant une tolérance immune, ce qui permettrait à la tumeur d'échapper au contrôle du système immunitaire et métastatiser plus facilement. Ces excitantes découvertes n'ont pas encore été établi et prouvé chez l'homme. Dans cette thèse, nous montrons pour la première fois que les vaisseaux lymphatiques sont directement impliqués dans la modulation de la réponse immunitaire au niveau local et systémique dans le mélanome chez l'homme. Ces récentes découvertes montrent le potentiel de combiner des thérapies visant le système lymphatique avec les immunothérapies actuellement utilisées afin d'améliorer le pronostic des patients atteint du mélanome. -- Cutaneous melanoma is one of the most invasive and metastatic human cancers and causes 75% of skin cancer mortality. Current therapies such as surgery and chemotherapy fail to control metastatic disease, and relapse occurs frequently due to microscopic residual lesions. It is, thus, essential to develop and optimize novel therapeutic strategies to improve curative responses in these patients. In recent decades, tumor immunologists have revealed the development of spontaneous adaptive immune responses in melanoma patients, leading to the accumulation of highly differentiated tumor-specific T cells at the tumor site. This remains one of the most powerful prognostic markers to date. Immunotherapies that augment the natural function of these tumor-specific T cells have since emerged as highly attractive therapeutic approaches to eliminate melanoma cells. While recent clinical trials have demonstrated great progress in the treatment of advanced stage melanoma, long-term disease control is still only achieved in a minority of patients. Local and systemic immune suppression by the tumor appears to be responsible, in part, for this poor clinical evolution. These facts underscore the need for a better analysis and characterization of immune- related pathways within the tumor microenvironment (TME), as well as at the systemic level. The overall goal of this thesis is, thus, to obtain greater insight into the complexity and heterogeneity of the TME in human melanoma, as well as to investigate immune modulation beyond the TME, which ultimately influences the immune system throughout the whole body. To achieve this, we established two main objectives: to precisely characterize local and systemic immune modulation (i) in untreated melanoma patients and (ii) in patients undergoing peptide vaccination or checkpoint blockade therapy with anti-cytotoxic T- lymphocyte-asisctaed protein-4 (CTLA-4) antibody. In the first and main part of this thesis, we analyzed lymphatic vessels in relation to anti-tumor immune responses in tissues from vaccinated patients using a combination of immunohistochemistry (IHC) techniques, whole slide scanning/analysis, and an automatic quantification system. Strikingly, we found that increased lymphatic vessel density was associated with high expression of immune suppressive molecules, low functionality of tumor-infiltrating CD8+ T cells and decreased cytokine production by tumor-antigen specific CD8+ T cells in the blood. These data revealed a previously unappreciated local and systemic role of lymphangiogenesis in modulating T cell responses in human cancer and support the use of therapies that target lymphatic vessels combined with existing and future T cell based therapies. In the second objective, we describe a metastatic melanoma patient who developed pulmonary sarcoid-like granulomatosis following repetitive vaccination with peptides and CpG. We demonstrated that the onset of this pulmonary autoimmune adverse event was related to the development of a strong and long-lasting tumor-specific CD8+ T cell response. This constitutes the first demonstration that a new generation tumor vaccine can induce the development of autoimmune adverse events. In the third objective, we assessed the use of Fourier Transform Infrared (FTIR) imaging to identify melanoma cells and lymphocyte subpopulations in lymph node (LN) metastasis tissues, thanks to a fruitful collaboration with researchers in Brussels. We demonstrated that the different cell types in metastatic LNs have different infrared spectral features allowing automated identification of these cells. This technic is therefore capable of distinguishing known and novel biological features in human tissues and has, therefore, significant potential as a tool for histopathological diagnosis and biomarker assessment. Finally, in the fourth objective, we investigated the role of colony- stimulating factor-1 (CSF-1) in modulating the anti-tumor response in ipilimumab-treated patients using IHC and in vitro co-cultures, revealing that melanoma cells produce CSF-1 via CTL-derived cytokines when attacked by cytotoxic T lymphocytes (CTLs), resulting in the recruitment of immunosuppressive monocytes. These findings support the combined use of CSF-1R blockade with T cell based immunotherapy for melanoma patients. Taken together, our results reveal the existence of novel mechanisms of immune modulation and thus promote the optimization of combination immunotherapies against melanoma. -- Le mélanome cutané est un des cancers humains les plus invasifs et métastatiques et est responsable de 75% de la mortalité liée aux cancers de la peau. Les thérapies comme la chirurgie et la chimiothérapie ont échoué à contrôler le mélanome métastatique, par ailleurs les rechutes sous ces traitements ont été montrées fréquentes. Il est donc essentiel de développer et d'optimiser de nouvelles stratégies thérapeutiques pour améliorer les réponses thérapeutiques de ces patients. Durant les dernières décennies, les immunologistes spécialisés dans les tumeurs ont démontré qu'un patient atteint du mélanome pouvait développer spontanément une réponse immune adaptative à sa tumeur et que l'accumulation de cellules T spécifiques tumorales au sein même de la tumeur était un des plus puissants facteurs pronostiques. Les immunothérapies qui ont pour but d'augmenter les fonctions naturelles de ces cellules T spécifiques tumorales ont donc émergé comme des approches thérapeutiques très attractives pour éliminer les cellules du mélanome. Alors que les derniers essais cliniques ont démontré un progrès important dans le traitement des formes avancées du mélanome, le contrôle de la maladie à long-terme est seulement atteint chez une minorité des patients. La suppression immune locale et systémique apparaitrait comme une des raisons expliquant la persistance d'un mauvais pronostic clinique chez ces patients. Ces considérations soulignent la nécessité de mieux analyser et caractériser les voies immunitaires non seulement au niveau local dans le microenvironement tumoral mais aussi au niveau systémique dans le sang des patients. Le but de cette thèse est d'obtenir une plus grande connaissance de la complexité et de l'hétérogénéité du microenvironement tumoral dans les mélanomes mais aussi d'investiguer la modulation immunitaire au delà du microenvironement tumoral au niveau systémique. Afin d'atteindre ce but, nous avons établi deux objectifs principaux : caractériser précisément la modulation locale et systémique du système immunitaire (i) chez les patients atteints du mélanome qui n'ont pas reçu de traitement et (ii) chez les patients qui ont été traités soit par des vaccins soit par des thérapies qui bloquent les points de contrôles. Dans la première et majeure partie de cette thèse, nous avons analysé les vaisseaux lymphatiques en relation avec la réponse immunitaire anti-tumorale dans les tissus des patients vaccinés grâce à des techniques d'immunohistochimie et de quantification informatisé et automatique des marquages. Nous avons trouvé qu'une densité élevée de vaisseaux lymphatiques dans la tumeur était associée à une plus grande expression de molécules immunosuppressives ainsi qu'à une diminution de la fonctionnalité des cellules T spécifiques tumoral dans la tumeur et dans le sang des patients. Ces résultats révèlent un rôle jusqu'à là inconnu des vaisseaux lymphatiques dans la modulation directe du système immunitaire au niveau local et systémique dans les cancers de l'homme. Cette recherche apporte finalement des preuves du potentiel de combiner des thérapies visant le système lymphatique avec des autres immunothérapies déjà utilisées en clinique. Dans le second objectif, nous rapportons le cas d'un patient atteint d'un mélanome avec de multiples métastases qui a développé à la suite de plusieurs vaccinations répétées et consécutives avec des peptides et du CpG, un évènement indésirable sous la forme d'une granulomatose pulmonaire sarcoid-like. Nous avons démontré que l'apparition de cet évènement était intimement liée au développement d'une réponse immunitaire durable et spécifique contre les antigènes de la tumeur. Par là- même, nous prouvons pour la première fois que la nouvelle génération de vaccins est aussi capable d'induire des effets indésirables auto-immuns. Pour le troisième objectif, nous avons voulu savoir si l'utilisation de la spectroscopie infrarouge à transformée de Fourier (IRTF) était capable d'identifier les cellules du mélanome ainsi que les différents sous-types cellulaires dans les ganglions métastatiques. Grâce à nos collaborateurs de Bruxelles, nous avons pu établir que les diverses composantes cellulaires des ganglions atteints par des métastases du mélanome présentaient des spectres infrarouges différents et qu'elles pouvaient être identifiées d'une façon automatique. Cette nouvelle technique permettrait donc de distinguer des caractéristiques biologiques connues ou nouvelles dans les tissus humains qui auraient des retombées pratiques importantes dans le diagnostic histopathologique et dans l'évaluation des biomarqueurs. Finalement dans le dernier objectif, nous avons investigué le rôle du facteur de stimulation des colonies (CSF-1) dans la modulation de la réponse immunitaire anti-tumorale chez les patients qui ont été traités par l'Ipilimumab. Nos expériences in vivo au niveau des tissus tumoraux et nos co-cultures in vitro nous ont permis de démontrer que les cytokines secrétées par les cellules T spécifiques anti-tumorales induisaient la sécrétion de CSF-1 dans les cellules du mélanome ce qui résultait en un recrutement de monocytes immunosuppresseurs. Dans son ensemble, cette thèse révèle donc l'existence de nouveaux mécanismes de modulation de la réponse immunitaire anti-tumorale et propose de nouvelles optimisations de combinaison d'immunothérapies contre le mélanome.

Vulnerability of stream biota to climate change in mediterranean climate regions: a synthesis of ecological responses and conservation challenges

Freshwater species worldwide are experiencing dramatic declines partly attributable to ongoing climate change. It is expected that the future effects of climate change could be particularly severe in mediterranean climate (med-) regions, which host many endemic species already under great stress from the high level of human development. In this article, we review the climate and climate-induced changes in streams of med-regions and the responses of stream biota, focusing on both observed and anticipated ecological responses. We also discuss current knowledge gaps and conservation challenges. Expected climate alterations have already been observed in the last decades, and include: increased annual average air temperatures; decreased annual average precipitation; hydrologic alterations; and an increase in frequency, intensity and duration of extreme events, such as floods, droughts and fires. Recent observations, which are concordant with forecasts built, show stream biota of med-regions when facing climate changes tend to be displaced towards higher elevations and upper latitudes, communities tend to change their composition and homogenize, while some life-history traits seem to provide biota with resilience and resistance to adapt to the new conditions (as being short-lived, small, and resistant to low streamflow and desiccation). Nevertheless, such responses may be insufficient to cope with current and future environmental changes. Accurate forecasts of biotic changes and possible adaptations are difficult to obtain in med-regions mainly because of the difficulty of distinguishing disturbances due to natural variability from the effects of climate change, particularly regarding hydrology. Long-term studies are needed to disentangle such variability and improve knowledge regarding the ecological responses and the detection of early warning signals to climate change. Investments should focus on taxa beyond fish and macroinvertebrates, and in covering the less studied regions of Chile and South Africa. Scientists, policy makers and water managers must be involved in the climate change dialogue because the freshwater conservation concerns are huge.

Characterization of Mechanically Alloyed Nanocrystalline Fe(Al): Crystallite Size and Dislocation Density

A nanostructured disordered Fe(Al) solid solution was obtained from elemental powders of Fe and Al using a high-energy ball mill. The transformations occurring in the material during milling were studied with the use of X-ray diffraction. In addition lattice microstrain, average crystallite size, dislocation density, and the lattice parameter were determined. Scanning electron microscopy (SEM) was employed to examine the morphology of the samples as a function of milling times. Thermal behaviour of the milled powders was examined by differential scanning calorimetry (DSC). The results, as well as dissimilarity between calorimetric curves of the powders after 2 and 20 h of milling, indicated the formation of a nanostructured Fe(Al) solid solution

Wine, alcohol, polyphenols and cardiovascular disease

Abstract. Excessive alcohol consumption is associated with increased morbidity and mortality as well as with labour and traffic accidents. However, current evidence suggests beneficial effects of moderate drinking on cardiovascular events including coronary heart disease, ischaemic stroke, peripheral arterial disease and congestive heart failure. The underlying mechanisms to explain these protective effects against coronary heart disease include an increase in high-density lipoprotein cholesterol and an increase in insulin sensitivity, and a decrease in platelet aggregation and circulating concentrations of fibrinogen. However, there are discrepancies regarding the specific effects of different types of beverages on the cardiovascular system, and also whether the possible protective effects of alcoholic beverages are due to their alcohol component (ethanol) or non-alcoholic products containing, mainly polyphenols. Recent randomised clinical trials have shown that wine, a polyphenol-rich alcoholic beverage, provides higher antioxidant and anti-inflammatory effects than some spirits such as gin, a polyphenol-free alcoholic beverage. In addition, dealcoholized red wine decreases blood pressure through a nitric oxide mediated mechanism, suggesting a protective effect of polyphenols on vascular function. Other studies performed in women have observed that daily doses of 1520 g of alcohol as red wine are sufficient to elicit protective effects similar to those observed in men who consumed higher doses of wine. In conclusion, moderate consumption of wine exerts a protective effect on biomarkers related to the progression and development of atherosclerosis due to its alcoholic (ethanol) and non-alcoholic (polyphenols) content. Women are more sensitive to the beneficial effects of wine.

Self-consistent theory of current and voltage noise in multimode ballistic conductors

Electron transport in a self-consistent potential along a ballistic two-terminal conductor has been investigated. We have derived general formulas which describe the nonlinear current-voltage characteristics, differential conductance, and low-frequency current and voltage noise assuming an arbitrary distribution function and correlation properties of injected electrons. The analytical results have been obtained for a wide range of biases: from equilibrium to high values beyond the linear-response regime. The particular case of a three-dimensional Fermi-Dirac injection has been analyzed. We show that the Coulomb correlations are manifested in the negative excess voltage noise, i.e., the voltage fluctuations under high-field transport conditions can be less than in equilibrium.

Economical and operational analysis of outsourced warehouse function

The target of the thesis was to find out has the decision to outsource part of Filtronic LK warehouse function been profitable. Furthermore, another thesis target was to demonstrate current logistics processes between TPLP and company and find out the targets for developing these processes. The decision to outsource part of logistical funtions have been profitable during the first business year. Partnership includes always business risks. Risk increases high asset specific investments. In the other hand investment to partnership increases mutual trust and commitment between parties. By developing partnership risks and opportunitic behaviour can be decreased. The potential of managing material and data flows between logistic service provider and company observed. By analyzing inventory effiency were highlighted the need for decreasing the capital invested to inventories. The recommendations for managing outsourced logistical funtions were established such as improving partnership, process development, performance measurement and invoice checking.

Eye Fundus Image Analysis for Automatic Detection of Diabetic Retinopathy

Diabetes is a rapidly increasing worldwide problem which is characterised by defective metabolism of glucose that causes long-term dysfunction and failure of various organs. The most common complication of diabetes is diabetic retinopathy (DR), which is one of the primary causes of blindness and visual impairment in adults. The rapid increase of diabetes pushes the limits of the current DR screening capabilities for which the digital imaging of the eye fundus (retinal imaging), and automatic or semi-automatic image analysis algorithms provide a potential solution. In this work, the use of colour in the detection of diabetic retinopathy is statistically studied using a supervised algorithm based on one-class classification and Gaussian mixture model estimation. The presented algorithm distinguishes a certain diabetic lesion type from all other possible objects in eye fundus images by only estimating the probability density function of that certain lesion type. For the training and ground truth estimation, the algorithm combines manual annotations of several experts for which the best practices were experimentally selected. By assessing the algorithm’s performance while conducting experiments with the colour space selection, both illuminance and colour correction, and background class information, the use of colour in the detection of diabetic retinopathy was quantitatively evaluated. Another contribution of this work is the benchmarking framework for eye fundus image analysis algorithms needed for the development of the automatic DR detection algorithms. The benchmarking framework provides guidelines on how to construct a benchmarking database that comprises true patient images, ground truth, and an evaluation protocol. The evaluation is based on the standard receiver operating characteristics analysis and it follows the medical practice in the decision making providing protocols for image- and pixel-based evaluations. During the work, two public medical image databases with ground truth were published: DIARETDB0 and DIARETDB1. The framework, DR databases and the final algorithm, are made public in the web to set the baseline results for automatic detection of diabetic retinopathy. Although deviating from the general context of the thesis, a simple and effective optic disc localisation method is presented. The optic disc localisation is discussed, since normal eye fundus structures are fundamental in the characterisation of DR.

Vascular Function in Chronic Kidney Disease and in Renovascular Disease

Cardiovascular mortality is 15 to 30 times higher in patients with chronic kidney disease than in the age-adjusted general population. Even minor renal dysfunction predicts cardiovascular events and death in the general population. In patients with atherosclerotic renovascular disease the annual cardiovascular event and death rate is even higher. The abnormalities in coronary and peripheral artery function in the different stages of chronic kidney disease and in renovascular disease are still poorly understood, nor have the cardiac effects of renal artery revascularization been well characterized, although considered to be beneficial. This study was conducted to characterize myocardial perfusion and peripheral endothelial function in patients with chronic kidney disease and in patients with atherosclerotic renovascular disease. Myocardial perfusion was measured with positron emission tomography (PET) and peripheral endothelial function with brachial artery flow-mediated dilatation. It has been suggested that the poor renal outcomes after the renal artery revascularization could be due to damage in the stenotic kidney parenchyma; especially the reduction in the microvascular density, changes mainly evident at the cortical level which controls almost 80% of the total renal blood flow. This study was also performed to measure the effect of renal artery stenosis revascularization on renal perfusion in patients with renovascular disease. In order to do that a PET-based method for quantification of renal perfusion was developed. The coronary flow reserve of patients with chronic kidney disease was similar to the coronary flow reserve of healthy controls. In renovascular disease the coronary flow reserve was, however, markedly reduced. Flow-mediated dilatation of brachial artery was decreased in patients with chronic kidney disease compared to healthy controls, and even more so in patients with renovascular disease. After renal artery stenosis revascularization, coronary vascular function and renal perfusion did not improve in patients with atherosclerotic renovascular disease, but in patients with bilateral renal artery stenosis, flow-mediated dilatation improved. Chronic kidney disease does not significantly affect coronary vascular function. On the contrary, coronary vascular function was severely deteriorated in patients with atherosclerotic renovascular disease, possibly because of diffuse coronary artery disease and/or diffuse microvascular disease. The peripheral endothelial function was disturbed in patients with chronic kidney disease and even more so in patient with atherosclerotic renovascular disease. Renal artery stenosis dilatation does not seem to offer any benefits over medical treatment in patients with renovascular disease, since revascularization does not improve coronary vascular function or renal perfusion.

Environmental adaptation of the source of the subbasin of Rico Stream, Monte Alto - SP, Brazil

The aim of this study was to define the photographic patterns that represent the use and occupation of the landcover of the "spring" of the Rico Stream subbasin, located at Monte Alto, state of São Paulo (SP), Brazil, for environmental adaptation regarding the Brazilian Forest Law. The mapping was performed using remote sensing techniques and visual interpretation of the World View image, followed by the digitalization of the net of drainage and vegetation (natural and agricultural) at the AutoCad software with documents and field work. The study area has 2141.53 ha and the results demonstrated that the main crop is sugarcane with 546.34 ha, followed by 251.22 ha of pastures, 191.71 ha of perennial crops, 57.31 ha of Eucalyptus and 49.52 ha of onion, confirming the advance of sugarcane culture in the region. The region has 375.04 ha of areas of permanent preservation (APPs), and of this area it was found that only 72.17 ha (19.24%) has arboreal vegetation or natural forest, and 302.87 ha of these areas need to be enriched and reforested with native vegetation from the region, according to the current legislation. The data of the area enable future proposals of models for environmental adaptation to the microbasin according to the current environmental legislation.

Laparoscopy in uterine cervical cancer. Current state and literature review

Cervical cancer remains the most frequent gynecological tumor in Brazil and other developing countries. Minimally invasive techniques, especially laparoscopy, have been increasingly employed in such tumors. This article aims to describe the main applications of laparoscopy in the treatment and staging of cervical cancer. In the early stages, it is possible to provide a fertility-preserving surgery in the form of radical trachelectomy and, in a study protocol, the function-preserving surgery, avoiding parametrectomy and the associated morbidity. A fully laparoscopic radical hysterectomy is fairly standard in the literature and has the tendency to become the standard of care in early cases, for patients who want to bear no more children. In advanced stages, minimally invasive surgery can offer ovarian transposition, with intent to prevent actinic castration, without upsetting the time for the start of radiotherapy and chemotherapy. Staging laparoscopic surgery, including pelvic and para-aortic lymphadenectomy, has been the subject of studies, since it has the potential to modify the extension of radiotherapy depending on the extent of lymph node spread.

Welding current effect on diffusible hydrogen content in flux cored arc weld metal

The application of flux cored arc welding (FCAW) has increased in manufacturing and fabrication. Even though FCAW is well known for its good capability in producing quality welds, few reports have been published on the cause of the relatively high diffusible hydrogen content in the weld metal and its relation with the ingredients used in the wire production and with the welding parameters (mainly welding current). This paper describes experiments where data obtained from weld metal diffusible hydrogen analysis, metal droplet collection, and high-speed recording of metal droplet transfer were used to evaluate the effect of welding current on diffusible hydrogen content in the weld metal. The results from gas chromatography analysis showed that weld metal hydrogen content indeed increased with welding current. A polynomial regressional analysis concluded that hydrogen increase with current was better described by a linear function with proportional constant of approximately 0.7 or 70%. Different from the GMA welding transfer behavior, statistical analysis showed only a small increase in metal droplet size with increasing current. The metal transfer mode remained in the globular range for currents between 100 and 150 A. The most surprising findings were with the high-speed cinematography recording. Observing the high speed movies, it was possible to see that at low current, "unmelted" flux sporadically touched the weld pool but at higher current, the flux remained touching the weld pool during the whole time of droplet formation and transfer. It is believed that since the flux has ingredients that contain hydrogen, hydrogen passes through the arc undisturbed, going to the weld bead intact and increasing the hydrogen content in the weld metal. Another important observation is regarding to droplet size. Droplet size increased with increasing current because forces from decomposed gases from the flux could sustain the droplets, retarding their transfer and allowing them to grow.

Interpreting marine benthic ecosystem functioning in coastal waters: validating the biological trait concept

Coastal areas harbour high biodiversity, but are simultaneously affected by rapid degradations of species and habitats due to human interactions. Such alterations also affect the functioning of the ecosystem, which is primarily governed by the characteristics or traits expressed by the organisms present. Marine benthic fauna is nvolved in numerous functions such as organic matter transformation and transport, secondary production, oxygen transport as well as nutrient cycling. Approaches utilising the variety of faunal traits to assess benthic community functioning have rapidly increased and shown the need for further development of the concept. In this thesis, I applied biological trait analysis that allows for assessments of a multitude of categorical traits and thus evaluation of multiple functional aspects simultaneously. I determined the functional trait structure, diversity and variability of coastal zoobenthic communities in the Baltic Sea. The measures were related to recruitment processes, habitat heterogeneity, large-scale environmental and taxonomic gradients as well as anthropogenic impacts. The studies comprised spatial scales from metres to thousands of kilometres, and temporal scales spanning one season as well as a decade. The benthic functional structure was found to vary within and between seagrass landscape microhabitats and four different habitats within a coastal bay, in papers I and II respectively. Expressions of trait categories varied within habitats, while the density of individuals was found to drive the functional differences between habitats. The findings in paper III unveiled high trait richness of Finnish coastal benthos (25 traits and 102 cateogries) although this differed between areas high and low in salinity and human pressure. In paper IV, the natural reduction in taxonomic richness across the Baltic Sea led to an overall reduction in function. However, functional richness in terms of number of trait categories remained comparatively high at low taxon richness. Changes in number of taxa within trait categories were also subtle and some individual categories were maintained or even increased. The temporal analysis in papers I and III highlighted generalities in trait expressions and dominant trait categories in a seagrass landscape as well as a “type organism” for the northern Baltic Sea. Some initial findings were made in all four papers on the role of common and rare species and traits for benthic community functioning. The findings show that common and rare species may not always express the same trait categories in relation to each other. Rare species in general did not express unique functional properties. In order to advance the understanding of the approach, I also assessed some issues concerning the limitations of the concept. This was conducted by evaluating the link between trait category and taxonomic richness using especially univariate measures. My results also show the need to collaborate nationally and internationally on safeguarding the utility of taxonomic and trait data. The findings also highlight the importance of including functional trait information into current efforts in marine spatial planning and biomonitoring.

Photosynthetic characteristics of hybrid and conventional rice plants as a function of plant competition

The objective of this work was to evaluate the characteristics related to the photosynthetic ability of hybrid and inbred rice varieties, as a way to assess which of the two presented higher potential to stand out under conditions of competition. The trial was set in a greenhouse in completely randomized block design and 2 x 6 factorial scheme with four replications. Factor A consisted of rice varieties (hybrid or inbred) and factor B by competition levels. Treatments consisted in maintaining one plant of either BRS Pelota (inbred) or Inov (hybrid) variety at the center of the plot, under competition with 0, 1, 2, 3, 4 or 5 plants of the variety BRS Pelota at the periphery of the experimental unit, according to the treatment. Fifty days after emergence (DAE), sub-stomatal CO2 concentration (Ci - mmol mol-1), photosynthetic rate (A - mmol m-2 s-1) and CO2 consumed (DC - mmol mol-1) were quantified, as well as shoot dry mass(SDM).Hybrid plants present higher photosynthesis capacity than inbred plants, when competing with up to 3 times its own density. When under the same competitive intensity, hybrid plants surpass the inbred. However, it should be emphasized that, when in farm condition, the lower competitive capacity with weeds often attributed to the hybrid varieties, probably is due to their lower planting density, but if weed competition is kept at low levels, hybrid rice plants may perform in the same way or usually better than inbred plants.

Spatial variations at different observational scales and the seasonal distributions of stream macroalgae in a Brazilian subtropical region

We examined the relationships between environmental variations in lotic ecosystems with the seasonal dynamics of macroalgae communities at different spatial scales: drainage basin of two rivers (Rio das Pedras and Rio Marrecas), shading (open and shaded stream segments), mesohabitat (riffles and pools), and microhabitats. Data collections were made on a monthly basis between January and December/2007. A total of 16 taxa were encountered (13 species and 3 vegetative groups). All of the biotic parameters (richness, abundance, diversity, equitability, and dominance) were found to be highly variable at all of the spatial scales evaluated. On the other hand, abiotic variables demonstrated differences only at mesohabitat (in terms of current velocity) and shaded habitat (in terms of irradiance) scales. The seasonality of the macroalgae community structure was strongly influenced by microhabitat variables (current velocity, substrate H', and irradiance), demonstrating their importance over time and at different scales. Regional variables (temperature, oxygen saturation, specific conductance, pH, and turbidity) were found to have little influence on the temporal dynamics of the macroalgae communities evaluated.

Calcium handling by vascular myocytes in hypertension

Calcium ions (Ca2+) trigger the contraction of vascular myocytes and the level of free intracellular Ca2+ within the myocyte is precisely regulated by sequestration and extrusion mechanisms. Extensive evidence indicates that a defect in the regulation of intracellular Ca2+ plays a role in the augmented vascular reactivity characteristic of clinical and experimental hypertension. For example, arteries from spontaneously hypertensive rats (SHR) have an increased contractile sensitivity to extracellular Ca2+ and intracellular Ca2+ levels are elevated in aortic smooth muscle cells of SHR. We hypothesize that these changes are due to an increase in membrane Ca2+ channel density and possibly function in vascular myocytes from hypertensive animals. Several observations using various experimental approaches support this hypothesis: 1) the contractile activity in response to depolarizing stimuli is increased in arteries from hypertensive animals demonstrating increased voltage-dependent Ca2+ channel activity in hypertension; 2) Ca2+ channel agonists such as Bay K 8644 produce contractions in isolated arterial segments from hypertensive rats and minimal contraction in those from normotensive rats; 3) intracellular Ca2+ concentration is abnormally increased in vascular myocytes from hypertensive animals following treatment with Ca2+ channel agonists and depolarizing interventions, and 4) using the voltage-clamp technique, the inward Ca2+ current in arterial myocytes from hypertensive rats is nearly twice as large as that from myocytes of normotensive rats. We suggest that an alteration in Ca2+ channel function and/or an increase in Ca2+ channel density, resulting from increased channel synthesis or reduced turnover, underlies the increased vascular reactivity characteristic of hypertension