bluuebunny/crossref_metadata_2025_split huggingface dataset:
Leucine induces phosphorylation and activation of p70S6K in cortical neurons via the system L amino acid transporter
Authors: Ishizuka Yuta , Kakiya Naomasa , Nawa Hiroyuki , Takei Nobuyuki 
Published: April 2008

Abstractp70S6 kinase is a multipotent kinase that phosphorylates substrates in response to extracellular stimuli. This kinase activity inhibits apoptosis, regulates cell size and controls translation. In the CNS, p70S6K also participates in synaptic plasticity. In this study, we report that leucine, a branched‐chain amino acid, induces phosphorylation and activation of p70S6 kinase in cortical neurons. Leucine also induces phosphorylation of S6 protein, a substrate of p70S6K. These effects of leucine are completely inhibited by rapamycin, consistent with mammalian target of rapamycin mediating p70S6 phosphorylation. Finally, we demonstrate that the action of leucine on cortical neurons is mediated by the system L amino acid transporter. Neurons express components of system L amino acid transporter LAT1, LAT2, and CD98. Leucine uptake and its effect on p70S6 kinase are both inhibited by a specific inhibitor of system L amino acid transporter. We propose that leucine plays important roles in regulating signaling by p70S6 kinase by acting as an intercellular communicator in the CNS.
THE INTERNATIONAL DIMENSIONS OF NEUROETHICS
Authors: LOMBERA SOFIA , ILLES JUDY 
Published: April 2008

ABSTRACTNeuroethics, in its modern form, investigates the impact of brain science in four basic dimensions: the self, social policy, practice and discourse. In this study, we analyzed a set of 461 peer‐reviewed articles with neuroethics content, published by authors from 32 countries. We analyzed the data for: (1) trends in the development of international neuroethics over time, and (2) how challenges at the intersection of ethics and neuroscience are viewed in countries that are considered developed by International Monetary Fund (IMF) standards, and in those that are developing. Our results demonstrate a steady increase in global participation in neuroethics from 1989 to 2005, characterized by an increase in numbers of articles published specifically on neuroethics, journals publishing these articles, and countries contributing to the literature. The focus from all countries was on the practice of brain science and the amelioration of neurological disease. Indicators of technology creation and diffusion in developing countries were specifically correlated with increases in publications concerning policy implications of brain science. Neuroethics is an international endeavor and, as such, should be sensitive to the impact that context has on acceptance and use of technological innovation.
Electron microscopy encounters with unusual thermophiles helps direct genomic analysis of Aciduliprofundum boonei
Authors: REYSENBACH A.‐L. , FLORES G. E. 
Published: April 2008

ABSTRACTTerry Beveridge's enthusiasm about the ingenuity of microorganisms has stimulated many new avenues of microbial research. One example where Terry's observations helped direct the scientific process was in the analysis of the draft genome of the thermoacidophilic archaeum, Aciduliprofundum boonei. This deep‐sea vent heterotroph ferments peptides as its primary metabolic pathway, using numerous enzymes encoding for proteolytic or peptidolytic activities. An almost complete modified Embden–Meyerhof–Parnas pathway operates in the gluconeogenic direction. Terry was particularly intrigued by the S‐layer and flagellum of A. boonei. Although only putative genes for the S‐layer protein could be identified, several genes encoding for glycosyl transferases were located in the draft genome that could glycosylate the S‐layer proteins and protect the proteins from the acidic environment. Furthermore, A. boonei possesses a unique organization to its flagellum genes and may represent a third organizational type within the Archaea.
Arterial stiffness, endothelial function and microcirculatory reactivity in healthy young males
Authors: Wright C. I. , Scholten H. J. , Schilder J. C. M. , Elsen B. M. , Hanselaar W. , Kroner C. I. , Draijer R. , Kastelein J. J. P. , Stok W. , Karemaker J. , De Groot E. 
Published: April 2008

SummaryLarge (C1) and small (C2) arterial stiffness has been suggested to parallel endothelial reactivity and has led researchers to suggest parameters of arterial stiffness may be alternative measures to brachial sonographic assessments of flow‐mediated dilatation (FMD). However, past studies comparing these measures can be criticized. In addition to %FMD responses, we recorded concurrent hyperaemic responses of the microcirculation and both were compared with C1 and C2. Twenty‐nine subjects 18–30 years of age were investigated. Radial blood pressure was recorded with a tonometer. Pulse waveform analysis was performed to calculate C1 and C2. These were compared with %FMD responses and responses of finger flux measured by laser Doppler fluxmetry (LDF); pulsatile finger volume measured by photoplethysmography (PPG); and palm skin temperature measured by infrared thermography (Tpalm) (i.e. microcirculatory responses). Responses were determined as % changes from control. We only found weak relationships between C1 and %FMD (r = 0·4, P = 0·04); C2 and %PPG (r = 0·38, P = 0·07); and C2 and %LDFdorsal (r = −0·38; P = 0·04). Responses of %FMD weakly parallel those of C1. Neither C2 nor C1 are viable indicators of endothelial or microcirculatory reactivity (i.e. hyperaemic or venous constriction) in healthy, resting young males. These findings refute the claims that C1 and C2 are substitute measures to sonographic assessments of brachial FMD.
Stimulant Induced Psychosis
Authors: Shibib Shatha , Chalhoub Nevyne 
Published: April 2008

Background:  Stimulants are used as a first line option in the treatment of ADHD and are amongst the safest drugs used in children and adolescents. The potential for psychotic side effects are well known, but reported as rare.Method:  We are reporting four cases of stimulant induced psychosis which presented over a 2 year period in a small community CAMHS setting.Results:  Our findings suggest that stimulant induced psychosis occurs. The symptoms in the early stages of the psychotic episode mimicked ADHD. Long acting preparations appeared to be a contributory factor to the development of psychotic side effects. Rechallenge with stimulant medication is described.Conclusion:  Psychosis is an important, unpredictable side effect of stimulant medication. Symptoms resolve with discontinuation of treatment. Remergence of ADHD symptoms are rapid and rechallenge is often indicated. It would be advisable for all professionals involved in the care and treatment of patients with ADHD to receive mental health training to aid the early recognition and appropriate management of such side effects.
Multiple erythema migrans – manifestation of systemic cutaneous borreliosis
Authors: Egberts Friederike , Möller Maike , Proksch Erhardt , Schwarz Thomas 
Published: April 2008

SummaryErythema migrans is the clinical hallmark lesion of a stage I infection with Borrelia burgdorferi. Multifocal lesions are rarely observed in Europe and thus may be missed, in particular when the typical clinical appearance of the pronounced advancing margin is missing.We present three patients with such a clinical appearance which caused differential diagnostic problems. Multiple erythema migrans represent an early stage of systemic infection. Thus early diagnosis and rapid initiation of therapy are warranted.
Recommendations for the use of rituximab (anti‐CD20 antibody) in the treatment of autoimmune bullous skin diseases§
Authors: Hertl Michael , Zillikens Detlef , Borradori Luca , Bruckner‐Tuderman Leena , Burckhard Harald , Eming Rüdiger , Engert Andreas , Goebeler Matthias , Hofmann Silke , Hunzelmann Nicolas , Karlhofer Franz , Kautz Ocko , Lippert Undine , Niedermeier Andrea , Nitschke Martin , Pfütze Martin , Reiser Marcel , Rose Christian , Schmidt Enno , Shimanovich Iakov , Sticherling Michael , Wolff‐Franke Sonja 
Published: April 2008

SummaryAutoimmune bullous skin disorders are induced by autoantibodies against distinct adhesion complexes of the epidermal and dermal‐epidermal junction. Since most of these disorders are characterized by a severe, potentially lethal course,they require long‐term immunosuppressive treatment to reduce the de novo synthesis of pathogenic autoantibodies by B lymphocytes. Rituximab, a chimeric monoclonal antibody against CD20 on B lymphocytes, has shown promise in several case reports or cohort studies in the treatment of paraneo‐plastic pemphigus,refractory cases of pemphigus vulgaris and foliaceus and in other autoimmune bullous disorders.Treatment with rituximab leads to depletion of pathogenic B‐cells which may last up to 12 months resulting in a reduction of plasma cells secreting pathogenic autoantibodies.Rituximab is usually administered in an adjuvant setting at a dose of 375 mg/m2 i.v.in weekly intervals for four consecutive weeks in addition to the standard immunosuppressive treatment.The present consensus statement of German‐speaking derma‐tologists,rheumatologists and oncologists summarizes and evaluates the current evidence for the use and mode of application of rituximab in autoimmune bullous skin disorders.
High‐dose intravenous corticosteroid pulse therapy in alopecia areata: Own experience compared with the literature
Authors: Luggen Peter , Hunziker Thomas 
Published: April 2008

Summary Background: Seven prospective studies including 193 patients have been published on high‐dose intravenous corticosteroid pulse therapy in alopecia areata (AA).We compare these data with a retrospective analysis of our own consecutive patients. Patients and Methods: Between 1998 and 2002,25 patients with severe AA were treated at the Department of Dermatology, University of Bern, with infusions of 500 mg methylprednisolone on 3 consecutive days.In addition to the inpatient records, in 2004 all patients were followed up by a questionnaire. Results: Four of 10 patients with multifocal AA and 3 of 9 patients with ophiasis‐type AA had full re‐growth of hair, whereas all 6 patients with AA totalis/universalis failed to respond. Conclusion: Intravenous corticosteroid pulse therapy may be helpful in the treatment of multifocal and ophiasis‐type AA.Patients with an initial episode of short duration have better chances for success.
Current therapeutic options of chronic leg ulcers
Authors: Renner Regina , Simon Jan C. 
Published: April 2008

SummaryWound treatment is continually becoming more complex and difficult. In the following review, we focus on the different options of wound debridement, stimulation of granulation tissue, different wound dressings, and therapeutic strategies in hard‐to‐heal‐wounds. We also present some future treatment options for chronic wounds.
Keratoacanthoma with perineural invasion: An indicator for aggressive behavior?
Authors: Basoglu Yasmin , Metze Dieter , Nashan Dorothee , Ständer Sonja 
Published: April 2008

SummaryNeurotropic invasion of keratoacanthoma (KA) is rare and can easily be missed histologically. A 36‐year‐old woman developed a KA on the upper lip four weeks after CO2 laser skin resurfacing; it showed microscopic evidence of perineural invasion. Despite repeated treatment with intralesional methotrexate, the KA recurred after 6 months. She was then treated with ionizing radiation (56 Gy) and has been tumor‐free for more than 3 years.Immunohistochemistry showed decreased expression of desmoglein 1 as it is seen in squamous cell carcinomas. In most cases not much importance is attached to perineural invasion which is frequently seen in KA because of the high rate of spontaneous regression. Our case suggests that perineural invasion may be an indicator for aggressive growth of head‐and‐neck KAs so that histologically‐controlled excision is recommended.
Big Fish are the Best: Seed Dispersal of Bactris glaucescens by the Pacu Fish (Piaractus mesopotamicus) in the Pantanal, Brazil
Authors: Galetti Mauro , Donatti Camila I. , Pizo Marco Aurélio , Giacomini Henrique C. 
Published: April 2008

ABSTRACTWe studied the potential role as seed disperser of the pacu fish (Piaractus mesopotamicus, Characidae) in the Pantanal of Brazil. The most important food item in the diet of the pacu in the wet season was fruits of the palm Bactris glaucescens found in the guts of 73 percent of all fishes collected (N= 70). We found a positive relationship between fish length, weight, and gape size and the number of intact seeds in their gut. Therefore, large pacus are especially important in dispersing B. glaucescens seeds within the studied system. Since the best seed dispersers are the largest fishes, which are preferred by commercial fisheries, we predict that the ongoing over fishing in freshwater ecosystems will have major impacts on the dispersal system of fish‐dependent plants. We suggest that it is paramount to change the attitudes in fisheries management of fruit‐eating fishes and urgent to evaluate the impact of fishing on forest regeneration.
Seedling Traits Determine Drought Tolerance of Tropical Tree Species
Authors: Poorter Lourens , Markesteijn Lars 
Published: April 2008

ABSTRACTWater availability is the most important factor determining tree species distribution in the tropics, but the underlying mechanisms are still not clear. In this study, we compared functional traits of 38 tropical tree species from dry and moist forest, and quantified their ability to survive drought in a dry‐down experiment in which wilting and survival were monitored. We evaluated how seedling traits affect drought survival, and how drought survival determines species distribution along the rainfall gradient. Dry forest species tended to have compound leaves, high stem dry matter content (stem dry mass/fresh mass), and low leaf area ratio, suggesting that reduction of transpiration and avoidance of xylem cavitation are important for their success. Three functional groups were identified based on the seedling traits: (1) drought avoiders with a deciduous leaf habitat and taproots; (2) drought resisters with tough tissues (i.e., a high dry matter content); and (3) light‐demanding moist forest species with a large belowground foraging capacity. Dry forest species had a longer drought survival time (62 d) than moist forest species (25 d). Deciduousness explained 69 percent of interspecific variation in drought survival. Among evergreen species, stem density explained 20 percent of the drought survival. Drought survival was not related to species distribution along the rainfall gradient, because it was mainly determined by deciduousness, and species with deciduous seedlings are found in both dry and moist forests. Among evergreen species, drought survival explained 28 percent of the variation in species position along the rainfall gradient. This suggests that, apart from drought tolerance, other factors such as history, dispersal limitation, shade tolerance, and fire shape species distribution patterns along the rainfall gradient.
Patterns of Land Cover Change in and Around Madidi National Park, Bolivia
Authors: Forrest Jessica L. , Sanderson Eric W. , Wallace Robert , Lazzo Teddy Marcelo Siles , Cerveró Luis Humberto Gómez , Coppolillo Peter 
Published: April 2008

ABSTRACTThis study examines how human land uses and biophysical factors serve as predictors of land cover change in and around Madidi National Park in Bolivia. The Greater Madidi Landscape ranges over an elevational gradient from < 200 m in the Amazon basin to 6000 m in the high Andes, contains more than ten major ecosystem types, and several protected areas and sustainable use zones. In this study, Landsat Thematic Mapper satellite images collected over the study area at the beginning of the 1990s and then the 2000s were classified according to broad land cover types. Below elevations of 3000 m, the landscape experienced equal rates of deforestation and secondary forest increases of approximately 0.63 percent annually, resulting in no significant net change. Below elevations of 1000 m, however, we found an annual net loss in forest cover of 0.11 percent. Across the landscape, land cover change was most likely to occur near areas previously deforested, near roads and population centers, and at low elevations. We found net deforestation rates to be inversely related to strength of natural resource protection laws in protected areas and other jurisdictions. Results suggest little net change for the landscape as a whole, but that local scale changes may be significant, particularly near roads. Management policies favorable for biodiversity conservation in this landscape should limit the building of new roads and immigration to biologically sensitive areas and continue to support protected areas, which are achieving a positive result for forest conservation.
Allometric Models for Predicting Aboveground Biomass in Two Widespread Woody Plants in Hawaii
Authors: Litton Creighton M. , Boone Kauffman J. 
Published: April 2008

ABSTRACTAllometric models are important for quantifying biomass and carbon storage in terrestrial ecosystems. Generalized allometry exists for tropical trees, but species‐ and site‐specific models are more accurate. We developed species‐specific models to predict aboveground biomass in two of the most ubiquitous natives in Hawaiian forests and shrublands, Metrosideros polymorpha and Dodonaea viscosa. The utility of the M. polymorpha allometry for predicting biomass across a range of sites was explored by comparing size structure (diameter at breast height vs. tree height) of the trees used to develop the models against trees from four M. polymorpha‐dominated forests along a precipitation gradient (1630–2380 mm). We also compared individual tree biomass estimated with the M. polymorpha model against existing generalized equations, and the D. viscosa model with an existing species‐specific model. Our models were highly significant and displayed minimal bias. Metrosideros polymorpha size structures from the three highest precipitation sites fell well within the 95% confidence intervals for the harvested trees, indicating that the models are applicable at these sites. However, size structure in the area with the lowest precipitation differed from those in the higher rainfall sites, emphasizing that care should be taken in applying the models too widely. Existing generalized allometry differed from the M. polymorpha model by up to 88 percent, particularly at the extremes of the data range examined, underestimating biomass in small trees and overestimating in large trees. The existing D. viscosa model underestimated biomass across all sizes by a mean of 43 percent compared to our model. The species‐specific models presented here should enable more accurate estimates of biomass and carbon sequestration in Hawaiian forests and shrublands.
Leaffall Phenology in a Subtropical Wet Forest in Puerto Rico: From Species to Community Patterns
Authors: Zalamea Marcela , González Grizelle 
Published: April 2008

ABSTRACTLeaffall phenology is an important periodical event in forests, contributing to mobilization of organic matter from primary producers to soil. For seasonal forests, leaffall periodicity has been related to rainfall regime and dry season length. In weakly seasonal forests, where there is no marked dry season, other climatic factors could trigger leaf shed. In this study, we aimed to determine if other climatic variables (wind speed, solar radiation, photosynthetic photon flux density [PPFD], day length, temperature, and relative humidity) could be better correlated with patterns of litter and leaffall in a weakly seasonal subtropical wet forest in Puerto Rico. Leaffall patterns were correlated mainly with solar radiation, PPFD, day length, and temperature; and secondarily with rainfall. Two main peaks of leaffall were observed: April–June and August–September, coinciding with the periods of major solar radiation at this latitude. Community leaffall patterns were the result of overlapping peaks of individual species. Of the 32 species analyzed, 21 showed phenological patterns, either unimodal (16 species), bimodal (three species), or multimodal (two species). Lianas also presented leaffall seasonality, suggesting that they are subject to the same constraints and triggering factors affecting trees. In addition to solar radiation as a main determinant of leaffall timing in tropical forests, our findings highlight the importance of interannual variation and asynchrony, suggesting that leaffall is the result of a complex interaction between environmental and physiological factors.
Altered Adhesive Structures and Their Relation to RhoGTPase Activation in Merlin‐Deficient Schwannoma
Authors: Flaiz Christine , Ammoun Sylwia , Biebl Anja , Hanemann C. Oliver 
Published: April 2008

AbstractSchwannomas are Schwann cell tumors of the nervous system that occur spontaneously and in patients with neurofibromatosis 2 (NF2) and lack the tumor suppressor merlin. Merlin is known to bind paxillin, beta1 integrin and focal adhesion kinase, members of focal contacts, multi‐protein complexes that mediate cell adhesion to the extracellular matrix. Moreover, merlin‐deficient Schwannomas show pathological adhesion to the extracellular matrix making the characterization of focal contacts indispensable. Using our Schwannoma in vitro model of human primary Schwann and Schwannoma cells, we here show that Schwannoma cells display an increased number of mature and stable focal contacts. In addition to an involvement of RhoA signaling via the Rho kinase ROCK, Rac1 plays a significant role in the pathological adhesion of Schwannoma cells. The Rac1 guanine exchange factor— beta‐Pix, localizes to focal contacts in human primary Schwannoma cells, and we show that part of the Rac1 activation, an effect of merlin‐deficiency, occurs at the level of focal contacts in human primary Schwannoma cells. Our results help explaining the pathological adhesion of Schwannoma cells, further strengthen the importance of RhoGTPase signaling in Schwannoma development, and suggest that merlin's role in tumor suppression is linked to focal contacts.
Parametric and Nonparametric Regression in the Presence of Endogenous Control Variables
Authors: Frölich Markus 
Published: April 2008

Summary The aim of this paper is to convey to a wider audience of applied statisticians that nonparametric (matching) estimation methods can be a very convenient tool to overcome problems with endogenous control variables. In empirical research one is often interested in the causal effect of a variable X on some outcome variable Y. With observational data, i.e. in the absence of random assignment, the correlation between X and Y generally does not reflect the treatment effect but is confounded by differences in observed and unobserved characteristics. Econometricians often use two different approaches to overcome this problem of confounding by other characteristics. First, controlling for observed characteristics, often referred to as selection on observables, or instrumental variables regression, usually with additional control variables. Instrumental variables estimation is probably the most important estimator in applied work. In many applications, these control variables are themselves correlated with the error term, making ordinary least squares and two‐stage least squares inconsistent. The usual solution is to search for additional instrumental variables for these endogenous control variables, which is often difficult. We argue that nonparametric methods help to reduce the number of instruments needed. In fact, we need only one instrument whereas with conventional approaches one may need two, three or even more instruments for consistency. Nonparametric matching estimators permit

consistent estimation without the need for (additional) instrumental variables and permit arbitrary functional forms and treatment effect heterogeneity.