bluuebunny/crossref_metadata_2025_split huggingface dataset:
Physiological and Transcriptomic Aspects of Urea Uptake and Assimilation in Arabidopsis Plants
Authors: Mérigout Patricia , Lelandais Maud , Bitton Frédérique , Renou Jean-Pierre , Briand Xavier , Meyer Christian , Daniel-Vedele Françoise 
Published: May 2008

Abstract
Urea is the major nitrogen (N) form supplied as fertilizer in agriculture, but it is also an important N metabolite in plants. Urea transport and assimilation were investigated in Arabidopsis (Arabidopsis thaliana). Uptake studies using 15N-labeled urea demonstrated the capacity of Arabidopsis to absorb urea and that the urea uptake was regulated by the initial N status of the plants. Urea uptake was stimulated by urea but was reduced by the presence of ammonium nitrate in the growth medium. N deficiency in plants did not affect urea uptake. Urea exerted a repressive effect on nitrate influx, whereas urea enhanced ammonium uptake. The use of [15N]urea and [15N]ammonium tracers allowed us to show that urea and ammonium assimilation pathways were similar. Finally, urea uptake was less efficient than nitrate uptake, and urea grown-plants presented signs of N starvation. We also report the first analysis, to our knowledge, of Arabidopsis gene expression profiling in response to urea. Our transcriptomic approach revealed that nitrate and ammonium transporters were transcriptionally regulated by urea as well as key enzymes of the glutamine synthetase-glutamate synthase pathway. AtDUR3, a high-affinity urea transporter in Arabidopsis, was strongly up-regulated by urea. Moreover, our transcriptomic data suggest that other genes are also involved in urea influx.
Magnitude and Direction of Vesicle Dynamics in Growing Pollen Tubes Using Spatiotemporal Image Correlation Spectroscopy and Fluorescence Recovery after Photobleaching
Authors: Bove Jérôme , Vaillancourt Benoit , Kroeger Jens , Hepler Peter K. , Wiseman Paul W. , Geitmann Anja 
Published: May 2008

Abstract
The delivery of cell wall material and membrane to growing plant cell surfaces requires the spatial and temporal coordination of secretory vesicle trafficking. Given the small size of vesicles, their dynamics is difficult to quantify. To quantitatively analyze vesicle dynamics in growing pollen tubes labeled with the styryl dye FM1-43, we applied spatiotemporal correlation spectroscopy on time-lapse series obtained with high-speed confocal laser scanning microscopy recordings. The resulting vector maps revealed that vesicles migrate toward the apex in the cell cortex and that they accumulate in an annulus-shaped region adjacent to the extreme tip and then turn back to flow rearward in the center of the tube. Fluorescence recovery after photobleaching confirmed vesicle accumulation in the shoulder of the apex, and it revealed that the extreme apex never recovers full fluorescence intensity. This is consistent with endocytotic activity occurring in this region. Fluorescence recovery after photobleaching analysis also allowed us to measure the turnover rate of the apical vesicle population, which was significantly more rapid than the theoretical rate computed based on requirements for new cell wall material. This may indicate that a significant portion of the vesicles delivered to the apex does not succeed in contacting the plasma membrane for delivery of their contents. Therefore, we propose that more than one passage into the apex may be needed for many vesicles before they fuse to the plasma membrane and deliver their contents.
The Arabidopsis BRAHMA Chromatin-Remodeling ATPase Is Involved in Repression of Seed Maturation Genes in Leaves
Authors: Tang Xurong , Hou Anfu , Babu Mohan , Nguyen Vi , Hurtado Lidia , Lu Qing , Reyes Jose C. , Wang Aiming , Keller Wilfred A. , Harada John J. , Tsang Edward W.T. , Cui Yuhai 
Published: May 2008

AbstractSynthesis and accumulation of seed storage proteins (SSPs) is an important aspect of the seed maturation program. Genes encoding SSPs are specifically and highly expressed in the seed during maturation. However, the mechanisms that repress the expression of these genes in leaf tissue are not well understood. To gain insight into the repression mechanisms, we performed a genetic screen for mutants that express SSPs in leaves. Here, we show that mutations affecting BRAHMA (BRM), a SNF2 chromatin-remodeling ATPase, cause ectopic expression of a subset of SSPs and other embryogenesis-related genes in leaf tissue. Consistent with the notion that such SNF2-like ATPases form protein complexes in vivo, we observed similar phenotypes for mutations of AtSWI3C, a BRM-interacting partner, and BSH, a SNF5 homolog and essential SWI/SNF subunit. Chromatin immunoprecipitation experiments show that BRM is recruited to the promoters of a number of embryogenesis genes in wild-type leaves, including the 2S genes, expressed in brm leaves. Consistent with its role in nucleosome remodeling, BRM appears to affect the chromatin structure of the At2S2 promoter. Thus, the BRM-containing chromatin-remodeling ATPase complex involved in many aspects of plant development mediates the repression of SSPs in leaf tissue.
The Maize Phytoene Synthase Gene Family: Overlapping Roles for Carotenogenesis in Endosperm, Photomorphogenesis, and Thermal Stress Tolerance
Authors: Li Faqiang , Vallabhaneni Ratnakar , Yu Jane , Rocheford Torbert , Wurtzel Eleanore T. 
Published: May 2008

Abstract
Carotenoids are essential for photosynthesis and photoprotection; they also serve as precursors to signaling molecules that influence plant development and biotic/abiotic stress responses. With potential to improve plant yield and nutritional quality, carotenoids are targets for metabolic breeding/engineering, particularly in the Poaceae (grass family), which includes the major food crops. Depending on genetic background, maize (Zea mays) endosperm carotenoid content varies, and therefore breeding-enhanced carotenoid levels have been of ongoing interest. The first committed step in the plastid-localized biosynthetic pathway is mediated by the nuclear-encoded phytoene synthase (PSY). The gene family in maize and other grasses contains three paralogs with specialized roles that are not well understood. Maize endosperm carotenoid accumulation requires PSY1 expression. A maize antibody was used to localize PSY1 to amyloplast envelope membranes and to determine PSY1 accumulation in relation to carotenoid accumulation in developing endosperm. To test when and if PSY transcript levels correlated with carotenoid content, advantage was taken of a maize germplasm diversity collection that exhibits genetic and chemical diversity. Total carotenoid content showed statistically significant correlation with endosperm transcript levels at 20 d after pollination for PSY1 but not PSY2 or PSY3. Timing of PSY1 transcript abundance, previously unknown, provides critical information for choosing breeding alleles or properly controlling introduced transgenes. PSY1 was unexpectedly found to have an additional role in photosynthetic tissue, where it was required for carotenogenesis in the dark and for heat stress tolerance. Leaf carotenogenesis was shown to require phytochrome-dependent and phytochrome-independent photoregulation of PSY2 plus nonphotoregulated PSY1 expression.
Population pharmacokinetic and pharmacodynamic analysis to support treatment optimization of combination chemotherapy with indisulam and carboplatin
Authors: Zandvliet Anthe S. , Schellens Jan H. M. , Dittrich Christian , Wanders Jantien , Beijnen Jos H. , Huitema Alwin D. R. 
Published: May 2008

WHAT IS ALREADY KNOWN ABOUT THIS SUBJECT • Chemotherapy with indisulam in combination with a standard dose of carboplatin was not well tolerated in a 3‐weekly regimen in a Phase I dose escalation study.• Myelosuppression was the dose limiting toxicity.• This pharmacokinetic–pharmacodynamic (PK–PD) study was performed to suggest a dosing regimen for the combination therapy indisulam–carboplatin that is well tolerated in patients. WHAT THIS STUDY ADDS • This PK–PD study supports the selection of indisulam 500 mg m−2 and a dose of carboplatin to achieve an AUC of 6 mg min−1 ml−1 in a 4‐weekly regimen as the recommended dose for future studies.AIMSIndisulam and carboplatin have shown synergistic activity in preclinical studies. In a dose escalation study of the combination, a treatment delay was frequently required in a 3‐weekly regimen to allow recovery from myelosuppression from previous cycles. A 4‐weekly regimen was better tolerated, but had a decreased dose‐intensity which may compromise efficacy. The aims of this study were (i) to develop a pharmacokinetic–pharmacodynamic (PK–PD) model to describe the myelosuppressive effect of the combination, and (ii) to use this model to select a dosing regimen for Phase II evaluation.METHODSSixteen patients were treated at four different dose levels of indisulam (1‐h infusion on day 1) and carboplatin (30‐min infusion on day 2). Pharmacokinetic data were analysed with nonlinear mixed effects modelling. A semiphysiological model describing chemotherapy‐induced myelosuppression characterized the relationship between the pharmacokinetics and the haematological toxicity of indisulam and carboplatin. A simulation study was performed to evaluate the tolerability and dose‐intensity for 3‐weekly and 4‐weekly treatment regimens.RESULTSThe PK–PD model described the pharmacokinetics and the myelosuppressive effect of indisulam and carboplatin. The risk of a treatment delay at cycle 2 due to myelosuppression was unacceptably high (34–65%) in a 3‐weekly regimen for various dose levels (350–600 mg m−2 indisulam in combination with carboplatin to achieve an AUC of 4–6 mg min−1 ml−1). This risk was acceptable for a 4‐weekly regimen (9–24%), which is in line with the clinical study results.CONCLUSIONSThis PK–PD study supports the selection of indisulam 500 mg m−2 and a dose of carboplatin to achieve an AUC of 6 mg min−1 ml−1 in a 4‐weekly regimen as the recommended dose for future studies.
A double‐blind placebo‐controlled birch allergy vaccination study II: correlation between inhibition of IgE binding, histamine release and facilitated allergen presentation
Authors: Würtzen P. A. , Lund G. , Lund K. , Arvidsson M. , Rak S. , Ipsen H. 
Published: May 2008

SummaryBackground
The pathogenesis of IgE‐mediated allergic disease is closely related to the production of T‐helper type 2 (Th2) cytokines, which lead to IgE production pivotal for activation of mast cells and basophils. Proliferating T cells along with eosinophils expanded and attracted by Th2 cytokines are major contributors to the late‐phase reaction. The activation of these Th2 cells is strongly enhanced by CD23‐mediated IgE facilitated allergen presentation (FAP).Objective
The present study aims to investigate the effect of specific immunotherapy (SIT)‐induced allergen‐specific non‐IgE antibodies (blocking antibodies) on IgE binding to allergen, histamine release (HR) and CD23‐mediated allergen uptake in antigen‐presenting cells.Methods
Competition between IgE and non‐IgE for allergen binding was studied by Advia Centaur antibody measurements, passively sensitized basophils were used to study HR and IgE‐facilitated binding of allergen to B cells (FAP) was studied by flow cytometry. FAP measurements were performed both with and without the addition of a reference IgE serum, which was included to obtain optimal complex formation. The serum samples were obtained from birch pollen immunotherapy (n=21) or placebo control patients (n=21) before and after 1 and 2 years of treatment.Results
Statistically significant reduction of all parameters investigated was observed after 1 year of treatment and the effect was maintained during the second year of treatment. There was a clear correlation between the two FAP measurements and between each of them and the level of T cell activation reported upon previously. Moreover, strong correlations were found between changes in FAP, IgE binding and HR.Conclusion
The present study clearly demonstrates that SIT induces changes in the composition of serum antibodies that inhibit IgE binding, HR and FAP to a similar extent. This suggests that these measurements, individually or in combination, may be used to monitor the immunological effect of SIT, even though direct correlations to changes in clinical parameters could not be demonstrated.
Oral delivery of Lactobacillus casei Shirota modifies allergen‐induced immune responses in allergic rhinitis
Authors: Ivory K. , Chambers S. J. , Pin C. , Prieto E. , Arqués J. L. , Nicoletti C. 
Published: May 2008

SummaryBackground
Changes in the composition of the gut microbiota have been implicated in the pathogenesis of allergic disorders, suggesting beneficial interactions between the intestinal immune system and specific bacterial strains. Lactobacilli are naturally present within the complex gastrointestinal microbiota of humans and they are currently present in many probiotic supplements.Objective
We sought to investigate the role that Lactobacillus casei Shirota (LcS) may play in modulating seasonal allergic rhinitis (SAR).Methods
The study format was double‐blinded, placebo‐controlled with 10 SAR sufferers in each group. We have documented and compared changes in immune status arising through the daily ingestion of a milk drink with or without live LcS, over a period of 5 months. Pre‐, peak‐ and post‐grass pollen season blood samples were collected for determination of plasma total IgE and grass pollen‐specific IgG and IgE levels by an enzyme immunoassay. At the same time, cytokine levels were determined by flow cytometric bead array technology following culture of peripheral blood mononuclear cells for 6 days in the presence or absence of specific grass pollen antigens.Results
Volunteers treated with LcS showed a significant reduction in levels of antigen‐induced IL‐5, IL‐6 and IFN‐γ production compared with volunteers supplemented with placebo. Meanwhile, levels of specific IgG increased and IgE decreased in the probiotic group.Conclusion
Changes in antigen‐induced production of cytokines were observed in patients treated with probiotics. These data show that probiotic supplementation modulates immune responses in allergic rhinitis and may have the potential to alleviate the severity of symptoms.
Clinical problems in the long‐term care of patients with chronic depression
Authors: Koekkoek Bauke , Van Meijel Berno , Schene Aart , Hutschemaekers Giel 
Published: May 2008

AbstractTitle.  Clinical problems in the long‐term care of patients with chronic depression. Aim.  This paper is a report of a study to explore problems encountered by mental health professionals in the long‐term care of patients with chronic depression.Background.  Patients who do not profit from psychopharmacological or psychotherapeutic treatment often need long‐term care. Although they experience severe symptoms and loss of functioning, little is known about these people and the care they receive.Method.  Experts in chronic depression (n = 8) participated in a four‐phase Delphi study in 2006–2007. Problems were elicited through a focus group interview (first round) which was analysed using thematic analysis. The resulting problem list was validated (second round) and scored twice on a 7‐point Likert scale (third and fourth rounds) by the participants. Urgency and changeability scores of 35 problems were obtained and a hierarchy of problems was set. In addition, qualitative data from the focus group interview were used to frame the results in the context of long‐term care for patients with chronic depression.Results.  Problems were subdivided into five areas. Relapses by the patient, a pessimistic attitude by the professional and demoralization in both were major problems. Also noted were the negative societal connotations of chronic depression and the lack of a coherent view on treatment within mental health care.Conclusion.  Chronicity of depression may be denied by both patients and professionals, resulting in an overly strong focus on cure and a limited quality of care. The results may be used as a starting point for construction of a best‐practice programme to improve long‐term care.
Assessment and documentation of patients’ nutritional status: perceptions of registered nurses and their chief nurses
Authors: Persenius Mona Wentzel , Hall‐Lord Marie‐Louise , Bååth Carina , Larsson Bodil Wilde 
Published: May 2008

Aims. To study, within municipal care and county council care, (1) chief nurses’ and registered nurses’ perceptions of patient nutritional status assessment and nutritional assessment/screening tools, (2) registered nurses’ perceptions of documentation in relation to nutrition and advantages and disadvantages with a documentation model.Background. Chief nurses and registered nurses have a responsibility to identify malnourished patients and those at risk of malnutrition.Design and methods. In this descriptive study, 15 chief nurses in municipal care and 27 chief nurses in county council care were interviewed by telephone via a semi‐structured interview guide. One hundred and thirty‐one registered nurses (response rate 72%) from 14 municipalities and 28 hospital wards responded to the questionnaire, all in one county.Results. According to the majority of chief nurses and registered nurses, only certain patients were assessed, on admission and/or during the stay. Nutritional assessment/screening tools and nutritional guidelines were seldom used. Most of the registered nurses documented nausea/vomiting, ability to eat and drink, diarrhoea and difficulties in chewing and swallowing, while energy intake and body mass index were rarely documented. However, the majority documented their judgement about the patient's nutritional condition. The registered nurses perceived the VIPS model (Swedish nursing documentation model) as a guideline as well as a model obstructing the information exchange. Differences were found between nurses (chief nurses/registered nurses) in municipal care and county council care, but not between registered nurses and their chief nurses.Conclusions. All patients are not nutritionally assessed and important nutritional parameters are not documented. Nutritionally compromised patients may remain unidentified and not properly cared for.Relevance to clinical practice. Assessment and documentation of the patients’ nutritional status should be routinely performed in a more structured way in both municipal care and county council care. There is a need for increased nutritional nursing knowledge.
Rekindling commitment: reflections from a pastoral educator enmeshed in direct support professional workforce development and person centered supports
Authors: Gaventa W. C. 
Published: May 2008

AbstractBackground Services with people with intellectual disabilities (ID) are increasingly structured by regulations, policies and licensing standards by public funding entities. The key responsibility for direct care staff often becomes that of compliance with all the rules and regulations.Method The impact of an increasing focus on compliance with regulations in the systems of services and supports for people with ID is explored along with the absence of focus on professional commitment and relationships. This exploration is done through a review of literature and also anecdotes and observations from 30 years of professional experience in working with direct care staff.Results Whether the source for enhanced regulation is concern about health and safety, honouring rights, meeting laws and/or an underlying fear that we cannot rely on the caregivers because of the turnover or lack of skill; we end up building a system based more and more on compliance, on regulations, programme and behavioural plans and competencies, without the same kind of concern or attention for people who are doing the caring, their motivation and what they need. One of the hypotheses and conclusions of this article is that the focus on compliance diminishes professional competence and commitment, and contributes both to staff disillusionment and to the rapid turnover.Conclusions As recruitment and turnover in the direct support professional workforce become ever more difficult problems, the newer focus on person‐centred planning, self‐directed supports and workforce development have both possibilities and problems in enhancing staff commitment in relationships with people they support. The importance of enhancing and supporting commitment also calls for new forms of professional identity and education that recapture the language and habits of commitment while also providing opportunities for staff to reflect on the values, visions and commitments that support their work.
The influence of low‐strain thermo‐mechanical processing on grain boundary network characteristics in type 304 austenitic stainless steel
Authors: ENGELBERG D. L. , HUMPHREYS F. J. , MARROW T. J. 
Published: May 2008

SummaryGrain boundary engineering of austenitic stainless steel, through the introduction of plastic strain and thermal annealing, can be used to develop microstructures with improved resistance to inter‐granular degradation. The influence of low‐strain thermo‐mechanical processing on grain boundary network development, with systematic variations of annealing treatments, has been investigated. Three stages of the microstructure development during grain boundary engineering in low‐strain processing conditions are identified, and correlated with changes in grain boundary character and deviation distributions. Low‐energy connected length segments at triple junctions, which have been proposed to be responsible for crack bridging during inter‐granular stress corrosion cracking, can be influenced by the choice of the annealing treatment parameters. The development of individual grain boundary length segments of different character showed consistent trends with increasing grain size. Crack length predictions are consistent with the beneficial effect of designing microstructures with high fractions of twin grain boundaries and smaller grain size.
Sub‐structure characterization of experimentally and naturally deformed ice using cryo‐EBSD
Authors: PIAZOLO S. , MONTAGNAT M. , BLACKFORD J. R. 
Published: May 2008

SummaryIn this work, we present first results of high‐resolution EBSD for ice with a spatial resolution down to 0.25 μm. The study highlights the potential of EBSD to significantly increase our understanding of deformation and annealing processes associated with the build‐up of internal stresses due to strain incompatibility between grains. Two polycrystalline samples were analyzed: a natural sample of polar ice from the Vostok ice core (Antarctica) and an experimentally deformed sample of laboratory grown columnar ice. In summary, we observe the following: (1) inhomogeneous deformation through the grains is translated into lattice distortions that are concentrated mainly at grain boundaries and triple junctions (natural and experimental sample), (2) these distortions may be continuous (natural and experimental sample) or may form distinct tilt boundaries and sub‐grains of 10–50 μm size (experimental sample). These form mainly by rearrangement of basal edge dislocations into low‐energy configurations (i.e. tilt boundaries) in various prism planes. Continuous lattice distortions originate from screw or mixed edge and screw dislocations lying in the basal plane.