bluuebunny/crossref_metadata_2025_split huggingface dataset:
CTLA‐4 regulates allergen response by modulating GATA‐3 protein level per cell
Authors: Nasta Francesca , Corinti Silvia , Bonura Angela , Colombo Paolo , Di Felice Gabriella , Pioli Claudio 
Published: February 2007

SummaryT helper type 2 (Th2) cell differentiation requires the expression of GATA‐3, a transcription factor that allows transcriptional activation of Th2 cytokine genes through chromatin remodelling. We investigated the role of the negative costimulatory receptor cytotoxic T‐lymphocyte antigen 4 (CTLA‐4) in the regulation of GATA‐3 expression, Th2 differentiation and immunoglobulin production during the immune response to allergens. BALB/c mice were immunized with a recombinant major allergenic component of Parietaria judaica pollen, rPar j I, and treated with blocking anti‐CTLA‐4 or control antibodies. Results showed that in vivo CTLA‐4 blockade enhanced the Par j I‐specific immunoglobulin E (IgE) serum level. In contrast, Par j I‐specific IgG2a serum level was reduced, suggesting that CTLA‐4 blockade skewed immunoglobulin production towards interleukin‐4 (IL‐4) ‐dependent immunoglobulin isotypes. Consistently, CTLA‐4 blockade increased the frequency of Par j I‐specific Th2 cells but not Th1 cells, as well as IL‐4 and IL‐5 but not interferon‐γ production. Our data also showed that CTLA‐4 blockade enhanced the GATA‐3 : T‐bet messenger RNA ratio. Interestingly, in vivo CTLA‐4 blockade did not increase the frequency of GATA‐3 protein‐expressing cells. In contrast, it enhances GATA‐3 protein level per cell. Further, in vitro results show that the anti‐CTLA‐4 monoclonal antibody, by competing with CD80 for CTLA‐4 binding, induced an enhancement in the frequency of IL‐4‐producing cells that correlates with the increase in GATA‐3 protein level per cell. In conclusion, CTLA‐4, by affecting the level of GATA‐3 per cell, contributes to keeping this factor under the threshold required to become a Th2 effector cell. Consequently, it affects IgE/IgG2a production and contributes to the outcome of allergen‐specific immune responses.
Immunosenescence: emerging challenges for an ageing population
Authors: Aw Danielle , Silva Alberto B. , Palmer Donald B. 
Published: February 2007

SummaryIt is now becoming apparent that the immune system undergoes age‐associated alterations, which accumulate to produce a progressive deterioration in the ability to respond to infections and to develop immunity after vaccination, both of which are associated with a higher mortality rate in the elderly. Immunosenescence, defined as the changes in the immune system associated with age, has been gathering interest in the scientific and health‐care sectors alike. The rise in its recognition is both pertinent and timely given the increasing average age and the corresponding failure to increase healthy life expectancy. This review attempts to highlight the age‐dependent defects in the innate and adaptive immune systems. While discussing the mechanisms that contribute to immunosenescence, with emphasis on the extrinsic factors, particular attention will be focused on thymic involution. Finally, we illuminate potential therapies that could be employed to help us live a longer, fuller and healthier life.
An improved method for angular‐resolved characterization of the optical anisotropy of pyrolytic carbon
Authors: REZNIK B. , GERTHSEN D. , BORTCHAGOVSKY E. 
Published: February 2007

SummaryA description is given of an experimental technique that improves the accuracy of the measurement of light extinctions by polarized light microscopy from deposits of pyrolytic carbon. The measurements were performed using a specially developed digital photometric image‐analysis procedure providing high spatial and angular resolution of light extinctions over the reflecting optical domains with a high dynamic range of grey levels. The digital image acquisition and data processing are illustrated using circular‐shaped pyrolytic carbon matrices of infiltrated carbon fibre felts and planar layers of pyrolytic graphite. The calculated value of the extinction angle for single crystalline graphite is discussed with respect to the experimental values for pyrolytic carbon with different degrees of optical anisotropy. Practical requirements for the accuracy of the method are discussed.
Optimized temporal response in multichannel two‐photon fluorescence lifetime microscopy using a photonic crystal fibre
Authors: BIRD D. K. , ELICEIRI K. W. , WHITE J. G. 
Published: February 2007

SummaryThe integration of fibre optics into an imaging system for the convenient delivery and collection of light has resulted in many hybrid forms of novel biomedical optical instrumentation. Although it is extremely robust and cost effective, fibre integration requires special consideration in a time‐domain fluorescence lifetime imaging schema where multipath propagation in the fibre causes significant spread in photon transit times. In this study, we investigated the effect of the length of a multimode collection fibre on the temporal performance of a multichannel fluorescence lifetime microscope and demonstrated the effectiveness of a photonic crystal fibre as a means of optimizing the collection and delivery of emitted fluorescence in terms of temporal resolution. The findings are pertinent to all studies that employ a multimode optical fibre to collect and deliver an emitted fluorescence signal from a sample to a remote detector for measurement of the characteristic fluorescence lifetime.
Transmission electron microscope specimen preparation for exploring the buried interfaces in plan view
Authors: RADNÓCZI G. Z. , PÉCZ B. 
Published: February 2007

SummaryA relatively easy and convenient process for the preparation of transmission electron microscope specimens of buried interfaces is described. The method is based on the alignment and realignment of the specimen rotation centre during ion milling. The ion‐milling time interval in which good samples are obtained is substantially extended in this way.
Stoichiometry and valence measurements of niobium oxides using electron energy‐loss spectroscopy
Authors: OLSZTA M. J. , WANG J. , DICKEY E. C. 
Published: February 2007

SummaryQualitative and quantitative electron energy‐loss spectroscopy analyses have been performed on niobium and stable niobium oxides (NbO, NbO2 and Nb2O5). At integration windows (Δ) greater than 75 eV, k‐factor analysis can be used to distinguish between the stoichiometry of the three oxides within 5.7% error. As seen in other metal oxides, with increasing oxidation state the metal ionization edges shift to higher energies relative to the O‐K edge. Normalized M2,3 white‐line intensities show a strong correlation with 4d occupancy for each compound. The data are in correspondence with that observed in the literature for 4d transition metals using normalized L2,3 white lines. Lastly, a distinctive energy‐loss near‐edge, structure of the O‐K edge was observed for each oxide, which could be used as a fingerprint for analysis of unknowns.
Making sense of nectar scents: the effects of nectar secondary metabolites on floral visitors of Nicotiana attenuata
Authors: Kessler Danny , Baldwin Ian T. 
Published: February 2007

SummaryFlowers produce a plethora of secondary metabolites but only nectar sugars, floral pigments and headspace volatiles have been examined in the context of pollinator behavior. We identify secondary metabolites in the headspace and nectar of glasshouse‐ and field‐grown Nicotiana attenuata plants, infer within‐flower origins by analyzing six flower parts, and compare the attractiveness of 16 constituents in standardized choice tests with two guilds of natural pollinators (Manducasexta moths and Archilochus alexandri and Selasphorus rufus hummingbirds) and one nectar thief (Solenopsis xyloni ants) to determine whether nectar metabolites can ‘filter’ flower visitors: only two could. Moths responded more strongly than did hummingbirds to headspace presentation of nicotine and benzylacetone, the most abundant repellent and attractant compounds, respectively. For both pollinators, nectar repellents decreased nectaring time and nectar volume removed, but increased visitation number, particularly for hummingbirds. Fewer ants visited if the nectar contained repellents. To determine whether nicotine reduced nectar removal rates in nature, we planted transformed, nicotine‐silenced plants into native populations in Utah over 2 years. Plants completely lacking nicotine in their nectar had 68–70% more nectar removed per night by the native community of floral visitors than did wild‐type plants. We hypothesize that nectar repellents optimize the number of flower visitors per volume of nectar produced, allowing plants to keep their nectar volumes small.
Mala s 12 is a major allergen in patients with atopic eczema and has sequence similarities to the GMC oxidoreductase family*
Authors: Zargari A. , Selander C. , Rasool O. , Ghanem M. , Gadda G. , Crameri R. , Scheynius A. 
Published: February 2007

Background:  Atopic eczema (AE) is a chronic inflammatory skin disorder, characterized by impaired skin barrier and itch. The yeast Malassezia belongs to the normal human skin microflora and can induce IgE‐ and T‐cell‐mediated allergic reactions in AE patients. Previously, we have identified several IgE‐binding components in Malassezia sympodialis extract.Methods:  Here, we report cloning, production and characterization of a M. sympodialis 67‐kDa allergen.Results:  The sequence of the 67‐kDa protein, termed Mala s 12, showed sequence similarity to the glucose–methanol–choline (GMC) oxidoreductase enzyme superfamily and was expressed as a recombinant protein in Escherichia coli. The purified protein bound flavin adenine dinucleotide with 1:1 stoichiometry per monomer of protein. The protein‐bound flavin showed an extinction coefficient at 451 nm of 11.3 mM−1cm−1. The recombinant 67‐kDa protein did not show any enzymatic activity when tested as oxidase or dehydrogenase using choline, glucose, myo‐inositol, methanol, ethanol, 1‐pentanol, benzyl alcohol, 2‐phenylethanol, cholesterol or lauryl alcohol as possible substrates. Recombinant Mala s 12 was recognized by serum IgE from 13 of 21 (62%) M. sympodialis‐sensitized AE patients indicating that the 67‐kDa component is a major allergen.Conclusions:  The data show that Mala s 12 has sequence similarity to the GMC oxidoreductase family and is a major allergen in AE patients.
Higher Bcl‐2 levels decrease staphylococcal superantigen‐induced apoptosis of CD4+ T cells in atopic dermatitis
Authors: Lin Y. T. , Wang C. T. , Lee J. H. , Chu C. Y. , Tsao W. C. , Yang Y. H. , Chiang B. L. 
Published: February 2007

Background:  Staphylococcal superantigens (SsAgs) contribute to the persistence of allergic skin inflammation in atopic dermatitis (AD). The aims of this study were to (1) determine whether there are differences between AD patients and healthy subjects in SsAg‐induced caspase‐3 activation and SsAg‐induced changes of anti‐apoptotic protein Bcl‐2 and Bcl‐2 mRNA levels of CD4+ T cells; (2) investigate the effect of interleukin (IL)‐4 on SsAg‐induced caspase‐3 activation and SsAg‐induced changes of Bcl‐2 and Bcl‐2 mRNA levels of CD4+ T cells.Methods:  Using immunofluorescence staining followed by flow cytometric analysis and real‐time PCR, we analyzed peripheral blood mononuclear cells with or without staphylococcal enterotoxin B (SEB) stimulation in the presence or absence of recombinant IL‐4 or anti‐IL‐4 neutralizing antibodies in 16 AD patients and 14 healthy subjects.Results:  SEB‐reactive (TCRVβ3+, Vβ12+, and Vβ17+) CD4+ T cells from AD patients were more resistant to SEB‐induced caspase‐3 activation and SEB‐induced decrease of Bcl‐2 and Bcl‐2 mRNA than those from healthy subjects. Exogenously added IL‐4 inhibited SEB‐induced caspase‐3 activation and SEB‐induced decrease of Bcl‐2 and Bcl‐2 mRNA in SEB‐reactive CD4+ T cells from healthy subjects. Inhibition of endogenous IL‐4 by using anti‐IL‐4 neutralizing antibodies up‐regulated SEB‐induced caspase‐3 activation and SEB‐induced decrease of Bcl‐2 and Bcl‐2 mRNA in SEB‐reactive CD4+ T cells from AD patients.Conclusions:  Following SsAg stimulation, IL‐4 produced by T cells in AD patients down‐regulates SsAg‐induced caspase‐3 activation and apoptosis of CD4+ T cells through inhibiting the decrease of Bcl‐2. This may impair deletion of SsAg‐activated T cells and resolution of allergic skin inflammation.
The effects on the lower esophageal sphincter of sevoflurane induction and increased intra‐abdominal pressure during laparoscopy
Authors: Thörn K. , Thörn S.‐E. , Wattwil M. 
Published: February 2007

Background:  Today sevoflurane is one of the most frequently used volatile anesthetics. The speed of induction can approach that of intravenous anesthetics, and case reports using sevoflurane induction for emergency anesthesia have been published. The purpose of this study in laparoscopic cholecystectomy patients was to investigate the effects of sevoflurane during inhalation induction on the lower esophageal sphincter pressure (LESP) and barrier pressure (BrP). The effects on lower esophageal sphincter (LES) and BrP of increased intra‐abdominal pressure during laparoscopy were also evaluated.Methods:  We recorded LESP and BrP in nine patients using a Dent sleeve device. Recordings were made before and after inhalation induction of anesthesia with 8% sevoflurane, as well as before and after insufflation of CO2 into the abdomen.Results:  After induction with sevoflurane, LESP (P= 0.039) and BrP (P= 0.020) decreased. Nevertheless, BrP was kept positive in all patients. Insufflation of CO2 into the abdomen during laparoscopy induced a significant increase in LESP (P= 0.02) and gastric pressure (P= 0.004). However, there was no significant change in BrP (P= 0.66); it increased in four patients and decreased in five.Conclusion:  BrP was kept positive in all patients after induction of anesthesia. Therefore, we believe that in combination with cricoid pressure, inhalation induction with sevoflurane might be a safe choice. As the adaptive increase in LESP during laparoscopy was not enough to retain a barrier pressure in all patients, it is important to be aware of the risk of regurgitation throughout the anesthesia.
Transfusion vs. alternative treatment modalities in acute bleeding: a systematic review
Authors: Heier H. E. , Bugge W. , Hjelmeland K. , Søreide E. , Sørlie D. , Håheim L. L. 
Published: February 2007

Background and methods:  The practice of transfusion varies a great deal between countries and hospitals. Therefore, a systematic literature review was performed to evaluate the evidence underlying practice of transfusion and alternative treatment modalities in acute bleeding. After a stepwise evaluation, 79 out of 2438 abstracts were approved as the evidence base.Results:  Albumin for volume therapy is not better than artificial colloids or crystalloids and may be detrimental in trauma patients. No outcome difference has been proved between artificial colloids and crystalloids. Use of hypertonic solutions remains controversial, as do the concepts of delayed and hypotensive resuscitation. Healthy individuals tolerate acute, normovolaemic anaemia at 5 g haemoglobin/dl, but pre‐operative haemoglobin < 6 g/dl gives increased mortality from surgical interventions. Keeping haemoglobin higher than 8–9 g/dl has not been associated with any positive effect on mortality or morbidity, even in patients with cardiovascular disease. The changes induced in erythrocytes by storage may be clinically insignificant. No alternative to erythrocyte transfusion was established. Evidence underlying the practice of thrombocyte and plasma transfusion is scarce. Available evidence on recombinant coagulation factor VIIa is insufficient to define its future role in acute bleedings. Antifibrinolytic drugs in general seem to reduce the need for transfusion.Conclusions:  Intravenous volume replacement and transfusion policies seem largely based on local tradition and expert opinions. As a result of the difficulties in performing controlled studies in patients with acute bleeding and the large number of patients needed to prove effects, other scientific evidence should be sought to better define best practice in this important field.
Anti‐inflammatory effect of high‐dose insulin treatment after urgent coronary revascularization surgery
Authors: Koskenkari J. K. , Kaukoranta P. K. , Rimpiläinen J. , Vainionpää V. , Ohtonen P. P. , Surcel H.‐M. , Juvonen T. , Ala‐Kokko T. I. 
Published: February 2007

Background:  The administration of insulin has been shown to exert cardioprotective and immunomodulatory properties. Ischemia and inflammation are typical features of acute coronary syndrome, thus it was hypothesized that high‐dose glucose–insulin–potassium (GIK) treatment could suppress the systemic inflammatory reaction and attenuate myocardial ischemia–reperfusion injury in patients with unstable angina pectoris after urgent coronary artery bypass surgery.Methods:  Forty patients with unstable angina pectoris scheduled for urgent coronary artery bypass surgery and cardiopulmonary bypass were randomly assigned to receive either high‐dose insulin treatment (short‐acting insulin 1 IU/kg/h with 30% glucose 1.5 ml/kg/h administered separately) or control treatment (saline). Blood glucose levels were targeted to 6.0–8.0 mmol/l in both groups by adjusting the rate of glucose infusion in the GIK group and by additional insulin in the control group as needed.Results:  High‐dose insulin treatment was associated with significantly lower average C‐reactive protein (23.8 vs. 40.1 mg/l, P= 0.008) and free fatty acid levels (0.22 vs. 0.41 mmol/l, P= < 0.001) post‐operatively. Average blood glucose levels were comparable during the intensive care unit (ICU) stay (7.1 vs. 6.9 mmol/l, P= 0.5) and 95% of the control patients received supplemental insulin. The pro‐inflammatory cytokine response [interleukin‐6 (IL‐6), interleukin‐8 (IL‐8) and tumor necrosis factor‐α (TNF‐α)] did not differ between the groups and beneficial effects on myocardial injury were not detected.Conclusions:  High‐dose insulin treatment has potential anti‐inflammatory properties independent of its ability to lower blood glucose levels. Even profound suppression of free fatty acid levels, the attenuation of myocardial ischemia–reperfusion injury was not detected.
Does Host Value Influence Female Aggressiveness, Contest Outcome and Fitness Gain in Parasitoids?
Authors: Goubault Marlene , Cortesero Anne Marie , Poinsot Denis , Wajnberg Eric , Boivin Guy 
Published: February 2007

AbstractIntraspecific competition for resources is common in animals and may lead to physical contests. Contest outcomes and aggressiveness can be influenced by the resource holding potential of contestants but also by their perception of the resource value (RV). Competitors may assess resource quality directly (real RV) but may also estimate it according to their physiological status and their experience of the habitat quality (subjective RV). In this article, we studied contests between females of the solitary parasitoidPachycrepoideus vindemmiaeRondani (Hymenoptera: Pteromalidae) when exploiting simultaneously a host, aDelia radicumL. (Diptera: Anthomyiidae) pupa. We tested the effect of factors modifying host value on the occurrence of agonistic behaviours, contest outcomes and host exploitation. The factors tested were: the quality of the previous habitat experienced by females, female egg load, host parasitism status and the stage reached by the owner female in her behavioural oviposition sequence. Females successfully protected their host against intruders during its exploitation, but not after oviposition, and their aggressiveness did not seem to be influenced by their perception of the RV. The fact that the host is subsequently parasitized by the opponent females appears to mainly depend on the host selectiveness of females.
Germination of Salicornia bigelovii Ecotypes under Stressing Conditions of Temperature and Salinity and Ameliorative Effects of Plant Growth‐promoting Bacteria
Authors: Rueda‐Puente E. O. , García‐Hernández J. L. , Preciado‐Rangel P. , Murillo‐Amador B. , Tarazón‐Herrera M. A. , Flores‐Hernández A. , Holguin‐Peña J. , Aybar A. N. , Barrón Hoyos J. M. , Weimers D. , Mwandemele O. , Kaaya G. , Mayoral J. L. , Troyo‐Diéguez E. 
Published: February 2007

AbstractSalinity is a major stress condition. Salicornia bigelovii is a valuable edible halophyte, considered to be a promising resource for cultivation in arid coastal zones. Its productivity depends on the supplementary provision of nitrogen, for which an option is chemical fertilization. Nevertheless, indiscriminate use of chemical fertilizers contributes to the problem of increased salinity. The inoculation of plant growth‐promoting bacteria (PGPB) represents an alternative. Seed ecotypes from four coastal areas [Santa Rosa Chica, Santa Rosa Grande, Santa Cruz and Cerro Prieto (CP), Sonora, México] were collected, in order to inoculate them with two species of PGPB (Azospirillum halopraeferens and Klebsiella pneumoniae). Two germination tests were carried out to study the effect of salinity, temperature regime (night/day) and inoculation with PGPB on germination (percentage and rate), plant height, root length and biomass produced (fresh and dry matter). In the first test, all four ecotypes were considered, whereas in the second test only the CP ecotype was involved because it was found to be the outstanding ecotype in the previous test. Results showed inhibition of germination when salinity was higher in all ecotypes except CP. The CP ecotype showed a decrease of seed germination with an increase in NaCl concentrations at all temperatures tested. However, when it was inoculated with both PGPB, the germination percentage was influenced.
Evolution and the latitudinal diversity gradient: speciation, extinction and biogeography
Authors: Mittelbach Gary G. , Schemske Douglas W. , Cornell Howard V. , Allen Andrew P. , Brown Jonathan M. , Bush Mark B. , Harrison Susan P. , Hurlbert Allen H. , Knowlton Nancy , Lessios Harilaos A. , McCain Christy M. , McCune Amy R. , McDade Lucinda A. , McPeek Mark A. , Near Thomas J. , Price Trevor D. , Ricklefs Robert E. , Roy Kaustuv , Sax Dov F. , Schluter Dolph , Sobel James M. , Turelli Michael 
Published: February 2007

AbstractA latitudinal gradient in biodiversity has existed since before the time of the dinosaurs, yet how and why this gradient arose remains unresolved. Here we review two major hypotheses for the origin of the latitudinal diversity gradient. The time and area hypothesis holds that tropical climates are older and historically larger, allowing more opportunity for diversification. This hypothesis is supported by observations that temperate taxa are often younger than, and nested within, tropical taxa, and that diversity is positively correlated with the age and area of geographical regions. The diversification rate hypothesis holds that tropical regions diversify faster due to higher rates of speciation (caused by increased opportunities for the evolution of reproductive isolation, or faster molecular evolution, or the increased importance of biotic interactions), or due to lower extinction rates. There is phylogenetic evidence for higher rates of diversification in tropical clades, and palaeontological data demonstrate higher rates of origination for tropical taxa, but mixed evidence for latitudinal differences in extinction rates. Studies of latitudinal variation in incipient speciation also suggest faster speciation in the tropics. Distinguishing the roles of history, speciation and extinction in the origin of the latitudinal gradient represents a major challenge to future research.