bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vitro activity of 20 agents in different prognostic subgroups of chronic lymphocytic leukemia – rolipram and prednisolone active in cells from patients with poor prognosis
Authors: Lindhagen Elin , Norberg Maria , Kanduri Meena , Tobin Gerard , Säisänen Laura , Åberg Magnus , Gustafsson Mats G. , Sundström Christer , Rosenquist Richard , Åleskog Anna 
Published: February 2009

AbstractBackground:  There is a need for development of new drugs for treatment of B‐cell chronic lymphocytic leukemia (CLL), especially for poor‐prognostic subgroups resistant to conventional therapy.Objective:  The in vitro antileukemic activity of 20 different anticancer agents was characterized in tumor cells from CLL, aiming at identifying agents active in poor‐prognostic subgroups.Design and methods:  In tumor cells from 40 CLL patients and in peripheral blood mononuclear cells (PBMC) from three healthy controls, the activity of 20 substances was assessed using a non‐clonogenic assay. The CLL samples were characterized regarding genomic aberrations by interphase fluorescence in situ hybridization and immunoglobulin heavy‐chain variable (IGHV) gene mutational status.Results:  In line with clinical experience, cells from patients with unfavourable genomic aberrations [del(11q)/del(17p)] showed lower drug sensitivity to fludarabine and chlorambucil than cells from patients with favourable cytogenetics [del(13q)/no aberration]. Most investigated drugs demonstrated similar activity in CLL cells from patients with unmutated and mutated IGHV genes as well as in CLL cells vs. PBMC. Interestingly, prednisolone and rolipram displayed high CLL specificity, high activity in CLL cells with unmutated IGHV genes and retained the effect in several cases with 11q/17p deletion. Further studies on prednisolone and rolipram revealed a synergy when these agents were combined in CLL cells, and suggested correlation between drug sensitivity and difference in downstream signaling.Conclusion:  Prednisolone and rolipram are interesting for further studies in CLL with inferior prognosis. The study can also be considered a basis for future efforts to find drugs active in subsets of CLL patients that are resistant to conventional therapy.
Blood flow measurements at different depths using photoplethysmography and laser Doppler techniques
Authors: Bergstrand Sara , Lindberg Lars Göran , Ek Anna‐Christina , Lindén Maria , Lindgren Margareta 
Published: February 2009

Background/purpose: This study has evaluated a multi‐parametric system combining laser Doppler flowmetry and photoplethysmography in a single probe for the simultaneous measurement of blood flow at different depths in the tissue. This system will be used to facilitate the understanding of pressure ulcer formation and in the evaluation of pressure ulcer mattresses.Methods: The blood flow in the tissue over the sacrum was measured before, during and after loading with 37.5 mmHg, respectively, 50.0 mmHg. The evaluation of the system consisted of one clinical part, and the other part focusing on the technicalities of the probe prototype.Results: An increase in blood flow while loading was the most common response, but when the blood flow decreased during loading it was most affected at the skin surface and the blood flow responses may be different due to depths of measurement. Reactive hyperaemia may occur more frequently in the superficial layers of the tissue.Conclusion: The study showed that the new system is satisfactory for measuring tissue blood flow at different depths. The laser Doppler complements the photoplethysmography, and further development of the system into a thin flexible probe with the ability to measure a larger area is required.
Facial Sweet syndrome mimicking photoallergic contact dermatitis
Authors: Johannemann Diana , Brunner Martina , Zouboulis Christos C. 
Published: February 2009

SummarySweet syndrome (acute febrile neutrophilic dermatosis) usually presents with painful erythematous plaques, malaise, and fever. Histologically skin infiltration with neutrophils is characteristic. The etiology of the disease is unknown. Sweet syndrome can be subdivided into the classical form, which is usually idiopathic and is associated with some kind of inflammation, the paraneoplastic form and the drug‐induced one. We present the unusual case of an 83‐year‐old woman who appeared to have facial photoallergic contact dermatitis but turned out to have facial Sweet syndrome.
Physical sunscreens with high sun protection factor may cause perioral dermatitis in children
Authors: Abeck Dietrich , Geisenfelder Birgitt , Brandt Oliver 
Published: February 2009

SummaryPerioral dermatitis is common in children and, if untreated, characterized by a chronic course lasting for months. Provocation factors known for adults, especially topical or inhaled corticosteroids, are relevant in children as well. We present eight children – all of them with dry skin – who developed perioral dermatitis after using sunscreens based on micropigments. This suggests that children with dry skin are at increased risk for perioral dermatitis. A history of sunscreen use should be specifically sought in children with perioral dermatitis.
Recombinase‐activating gene 1 immunodeficiency: different immunological phenotypes in three siblings
Authors: Pasic Srdjan , Djuricic Slavisa , Ristic Goran , Slavkovic Bojana 
Published: February 2009

AbstractWe report different immunological phenotypes in three siblings from consanguineous family with recombinase‐activating gene 1 (RAG1) gene mutations. Null mutations of RAG genes result in severe combined immunodeficiency (SCID) with absent T and B cells. Hypomorphic mutations with retained activity of RAG genes may lead to a ‘leaky’ SCID with some features of Omenn syndrome (OS) or typical OS. In our three patients, homozygous, hypomorphic RAG1 gene mutation (g.368–369delAA) was detected. Two patients presented with T−B−SCID phenotype while the youngest patient developed T+B+NK+SCID phenotype with expansion of autologous T‐cell receptor (TCR) γδ‐positive T cells, increased immunoglobulin levels and retained ability for antibody production. Similar to originally reported patients with this newly recognized immune phenotype, our patient developed disseminated cytomegalovirus (CMV) infection and autoimmune cytopenia.Conclusion: In infants with disseminated cytomegalovirus infection and autoimmune cytopenia, even if basic immunologic investigation appears normal, RAG1 immunodeficiency should be considered.
Alternative stable states in a wet calcareous dune slack in The Netherlands
Authors: Adema Erwin B. , Grootjans Ab P. , Petersen Jörg , Grijpstra Johan 
Published: February 2009

Abstract. Evidence is presented for the occurrence of alternative stable states in a wet calcareous dune slack on the Frisian island of Texel, The Netherlands. An early pioneer stage (0.5 kgm−2 total standing crop) and a more productive later successional stage (2.9 kg m−2) occur side by side, with sharp boundaries between them. The pioneer vegetation has been recorded at the site for more than 62 yr. These features indicate the occurrence of a positive‐feedback mechanism that has led to alternative stable states.Analyses of ground and surface water composition, and decalcification depths, indicated that hydrologically the study site can be characterized as a flow‐through slack, with exfiltration of calcareous groundwater on one side and infiltration of surface water on the other side of the slack. These differences in hydrological conditions have led to distinct differences in environmental conditions within the dune slack. The occurrence of the two successional stages can, however, not be explained by differences in hydrological conditions since both stages occur side by side in the centre of the dune slack. It is, therefore, more likely that biotic interactions are the cause of the vegetation pattern. Three possible mechanisms for feedback processes are discussed: (1) enhanced nitrogen loss; (2) sulfide toxicity and (3) nutrient accumulation in internal cycle.
Effects of regional climate and small‐scale habitat quality on performance in the relict species Ramonda myconi
Authors: Riba M. , Picó F.X. , Mayol M. 
Published: February 2009

Abstract. The Mediterranean Basin harbours paleo‐endemic species with a highly restricted and fragmented distribution. Many of them might also be of the remnant type, for which the regional dynamics depends on the persistence of extant populations. Therefore, a key issue for the long‐term persistence of these species is to assess the variability and effects of ecological factors determining plant performance. We investigated the spatio‐temporal variability in plant traits and ecological factors of Ramonda myconi, a preglacial relict species with remnant dynamics, in 5 populations over 4–7 yr.Ecological factors contributing to fecundity showed a high degree of between‐year variability. Pre‐dispersal fruit predation had a minor influence on total reproductive output, and most of the variability was found among individuals within populations and years. Spatio‐temporal variability in growth and survival was rather low but significant, whereas recruitment showed important between‐population variability. Among‐year variability in fecundity and growth was related to climatic fluctuations on a regional scale, notably rainfall and temperature in a particular period, while the spatial variability in survival and recruitment was explained by within‐population (patch) habitat quality. Although R. myconi is able to withstand repeated periods of drought, water availability seems to be the most important factor affecting plant performance in all the study populations. These findings suggest that the long‐term persistence of species showing remnant population dynamics in habitats under the influence of Mediterranean climate might be threatened by increased aridity as a result of climate change.
Invasibility of a coastal strip in NE Spain by alien plants
Authors: Sobrino Eduardo , Sanz‐Elorza Mario , Dana Elías D. , González‐Moreno Alberto 
Published: February 2009

Abstract. The alien plant species and the ecological factors that facilitate their invasion to a coastal strip in the Baix Camp region (Tarragona, NE Spain) were studied. A detailed inventory of the area showed that 20% of the plant species, most of them from the American Continent, were aliens, many of which were strongly invasive.At the habitat level, the relationships between the invasive behaviour and a number of autecological, ecological and habitat variables were analysed by means of logistic analyses. In the best model five variables were related to alien plant invasions: climatic affinity, disturbance of the invaded habitat, route of introduction, soil moisture during summer, and life form. To elucidate the environmental factors that could be responsible for alien plant invasions at a regional scale, the number of alien taxa and the environmental features at 13 localities of the western Mediterranean area were analysed. The warm lowlands, subjected to low annual rainfall and high population density, exhibited the greatest reception capacity for alien plants.It is concluded that various specific environmental features – high mean temperatures, the abundance of riparian systems, the existence of biotopes with favourable water balance which harbour a great richness of alien species and the high human pressure to which the enclave is subjected, combined with the ecological requirements of the alien species and certain species attributes (biotype) can interact at different scales and have caused the over‐representation of alien plants.
Mechanisms blocking Pinus sylvestris colonization of Mediterranean mountain meadows
Authors: Castro Jorge , Zamora Regino , Hódar José A. 
Published: February 2009

Abstract. In southern Mediterranean Pinus sylvestris forests there are grassy meadows that resist invasion of trees despite the proximity to seed sources. In this study, we investigate the mechanisms blocking colonization by Pinus sylvestris of the meadows. Two experiments were conducted in which seeds were sown either at 1 cm depth or on the surface to simulate dispersal, and three treatments of vegetation removal were applied: Disturbed (where the herbaceous layer was eliminated, exposing the mineral soil), Clipped (vegetation cut at ground level) and Control (no disturbance of the herbaceous layer). In addition, the effect of seed predators was controlled by using wire cages in the case of the surface sown experiment.When seeds were sown at 1 cm depth, seedling emergence was not reduced by the herbaceous layer. In contrast, when seeds were surface sown and predators were excluded, the rate of emergence was low in the Control treatment, intermediate in Clipped and high in Disturbed. Seedling emergence was, however, minimal when predators were not excluded, irrespective of the disturbance level. Seedling survival and growth after three years of study were similar among treatments. The results show that the seed predation and the physical barrier created by the herbaceous layer are the two mechanisms blocking the encroachment of Pinus sylvestris onto these Mediterranean mountain meadows, limiting the regeneration and potential expansion of the forest.
A model for seasonality and distribution of leaf area index of forests and its application to China
Authors: Luo Tianxiang , Neilson Ronald P. , Tian Hanqin , Vörösmarty Charles J. , Zhu Huazhong , Liu Shirong 
Published: February 2009

Abstract. We have constructed a phenological model of leaf area index (LAI) of forests based on biological principles of leaf growth. Field data of maximum LAI from 794 plots with mature or nearly mature stand ages over China were used to parameterize and calibrate the model. New measurements of maximum LAI from 16 natural forest sites were used to validate the simulated maximum LAI. The predictions of seasonal LAI patterns were compared with seasonal changes derived from the 1‐km satellite AVHRR‐NDVI data for nine undisturbed forest sites in eastern China. Then, we used the model to map maximum LAI values for forests in China.Model results indicated that the PhenLAI model generally predicted maximum LAI well for most forest types, even when maximum LAI is > 6. This suggests an ecological approach to the saturation problem in satellite detection of high forest LAI where the relationship between NDVI and LAI reaches an asymptote near a projected LAI value of 5 or 6. Furthermore, the predictions of seasonal LAI patterns in timing and dynamics were generally consistent with the satellite NDVI changes, except for monsoon forest and rain forest in south China where satellite detection of seasonal variation in leaf area is hardly possible. Compared with average projected LAI measurements of global forests from 809 field plots in literature data, our maximum LAI values were close to the global literature data for most of Chinese forests, but the average area‐weighted maximum LAI for all forests of China (6.68 ± 3.85) was higher than the global mean LAI of the 809 field plots (5.55 ± 4.14). We believe that forest LAI in China is commonly > 6, especially in tropical rainforest, subtropical evergreen broad‐leaved forest, temperate mixed forest, and boreal/alpine spruce‐fir forest where satellite detection of high LAI is hardly possible.
Submerged macrophyte zonation in a Mediterranean salt marsh: a facilitation effect from established helophytes?
Authors: Espinar J.L. , García L.V. , García Murillo P. , Toja J. 
Published: February 2009

Abstract. The relationship between communities of submerged annual macrophytes (predominately Chara spp.) and environmental characteristics is studied in three habitats with different dominant perennial species (Arthrocnemum, Juncus, Scirpus) and areas of bare soil. The distribution of submerged annual macrophytes is significantly dependent on two independent environmental factors: a dominant gradient of flooding/salinity, and a secondary gradient of nutrients related exclusively to the combined abundance of helophytes of the genus Scirpus (S. maritimus and S. litoralis). The results suggest that these emergent helophytes (1) are able to modify water column parameters (such as concentration of nitrates, phosphates, potassium, and bicarbonates) which are important for the communities of submerged macrophytes, and (2) play a fundamental role in the generation of secondary sources of environmental variability which, superimposed on the main gradient of flooding/salinity, favours the appearance of new compositional equilibria in such communities.The existence of a process of facilitation is discussed by which the emergent helophytes induce changes in nutrient availability that would favour relatively nutrient‐demanding charophyte species (such as Chara connivens and Nitella hyalina), altering the established relationships with other coexisting charophytes (such as Chara canescens and C. galioides) that dominate in the absence of the facilitating species. Nevertheless, the increased nutrient concentration associated to the presence of helophytes would not introduce significant changes in the total biomass of submerged aquatic macrophytes.
Niche differentiation and distribution of Carex curvula along a bioclimatic gradient in the southwestern Alps
Authors: Choler Philippe , Michalet Richard 
Published: February 2009

Abstract. Carex curvula is a dominant sedge of European alpine tundra, exhibiting two morphological forms: C. curvula ssp. curvula (Ccc) and C. curvula ssp. rosae (Ccr). In this paper, we attempt to explore whether Ccc and Ccr are ecotypes or vicariant forms and whether between‐ and within‐regional distribution patterns can be explained by variations in the amount of available habitats and/or by changes in niche attributes. The study area covered three bioclimatically distinct regions of the southwestern Alps in which local abundances of Ccc and Ccr strongly differ.The realized niche of both forms was investigated by a direct gradient analysis performed on an extensive floristic and environmental data set. We found no evidence of niche overlap between Ccc and Ccr as their distribution curves differ strongly along disturbance, mesotopography and soil acidity gradients. We investigated the effect of region on the structure of local scale variables tables. Highly concordant patterns among regions were found, except that optimal habitat conditions for Ccc were infrequent in the southernmost regions. We compared the ecological behaviour of range centre and range margin populations of each form. We found a narrower ecological amplitude for Ccr in the northern part of its range, whereas for Ccc the niche breadth of range‐margin populations was not reduced compared to range centre populations. At its southern range limit, Ccc mostly occupies ecologically marginal habitats.We conclude that Ccc and Ccr represent ecotypes, not vicariant forms. Finally, we suggest that habitat availability, resulting from the interplay of regional‐scale and local‐scale variables, satisfactorily explains the distributional patterns of Carex curvula ecotypes in the southwestern Alps.
Plant communities along environmental gradients of high‐arctic mires in Sassendalen, Svalbard
Authors: Vanderpuye Archibald W. , Elvebakk Arve , Nilsen Lennart 
Published: February 2009

Abstract. The wet to moist bryophyte‐dominated vegetation of Sassendalen, Svalbard, was classified into seven communities. These communities were grouped into (1) Cardamino nymanii‐Saxifragion foliolosae marsh; (2) Caricion stantis fen; (3) Luzulion nivalis snowbed – including manured vegetation corresponding to moss tundras. All communities have a basically arctic distribution. Marshes are developed in habitats with a water table above the bryophyte vegetation surface and fens on sites with a water table level high above the permafrost but below the bryophyte surface. Moss tundras normally have no standing water table, but in Sassendalen they have a low water table due to their development on less steep slopes than in their normal habitat near bird cliffs.CCA confirms that the standing water level is the prime differentiating factor between the alliances, while aspect favourability and permafrost depth differentiate between the fen communities and temporary desiccation is important for the Catoscopium nigritum community. Carex subspathacea is a characteristic fen species in the absence of other Carex species dominating elsewhere in the Arctic. Arctic marshes are linked to an extremely cold environment. They have a very low species diversity with a few species dominating; Arctophila fulva, Pseudocalliergon trifarium, Scorpidium scorpioides and Warnstorfia tundrae are character species. Moss tundra as defined here appears to be restricted to Svalbard and, probably, neighbouring Novaya Zemlya. This may be due to the absence of rodents and the high seabird density, which is related to the mild sea currents reaching further to the north here and which implies manuring of surrounding ecosystems. Manuring in a very cold environment produces moss carpets with a thin active layer and accumulation of thick peat layers without a standing water level. In Sassendalen the role of arctic seabirds is replaced by Svalbard reindeer which are nonmigratory and are concentrated to favourable grazing areas where their manuring effect is intense. Their long‐term manuring effect probably explains the occurrence of moss tundras in this weakly rolling landscape where seabird colonies are absent.
BOOK REVIEWS
Authors: Collins Beverly S. 
Published: February 2009

Book reviewed in this article:Hutchings, M. J., John, E. A., and Stewart, A. J. A. (eds.) The Ecological Consequences of Environmental Heterogeneity. xiii + 434 pp. Blackwell Science Ltd., Oxford. ISBN 0‐632‐05713‐0. Price: USD 47.66
Species richness, alien species and plant traits in Central Argentine mountain grasslands
Authors: Cantero J.J. , Liira J. , Cisneros J.M. , Gonzalez J. , Nuñez C. , Petryna L. , Cholaky C. , Zobel M. 
Published: February 2009

Abstract. Pattern of native vegetation, distribution of alien species and variation of environmental parameters were studied in mountain grasslands in a lithologically homogeneous Córdoba mountain range in Central Argentina. CCA showed that altitude was the most important factor determining the compositional variation of the vegetation, with soil nutrient status and stoniness as additional factors. Short‐grass communities, associated with the driest habitats on plateaus, showed higher small‐scale native species richness than wet‐turf communities in valleys and tall‐grass communities on slopes. Species richness was negatively correlated with soil parameters that indicate nutrient status and water availability. Also, there was a negative correlation between soil Ca‐ and Mg‐ content and richness. High native species richness coincided with high alien species richness. When smaller units – community types – were considered, it became evident that within short‐grass vegetation, the three most species‐rich community types contained significant numbers of alien species, while the other two did not. Even within one community type, the same quadrats that contained the highest number of native species, were also characterized by the highest numbers of alien species. Evidently, the same mechanism was responsible for high richness of both native and alien species. Alien species were distinguished by a greater proportion of annuals and prostrate stoloniferous plants, by lower palatability and by smaller proportion of zoochory.DCA ordination of quadrats on the basis of plant traits as attributes resulted in a clear distinction of three main vegetation types. Short‐grass vegetation was distinguished by a predomination of late flowering species, tall‐grass vegetation by the presence of high herbaceous plants and bushes, and wet‐turf vegetation by the presence of plants with storage organs, the lack of hairy leaves, and by a high proportion of cryptophytes. Quadrats with and without alien species were distinguished as well, indicating that the occurrence of aliens may be dependent on plant traits in a particular patch of a community.