bluuebunny/crossref_metadata_2025_split huggingface dataset:
Interleukin‐21 activates human natural killer cells and modulates their surface receptor expression
Authors: Skak Kresten , Frederiksen Klaus Stensgaard , Lundsgaard Dorthe 
Published: November 2007

SummaryInterleukin (IL)‐21 is a novel cytokine that has been shown to enhance proliferation and activation of CD8+ T cells, enhance natural killer (NK) cell activity and costimulate anti‐CD40‐driven B‐cell proliferation in mice. Several studies have furthermore demonstrated antitumour effects of IL‐21 administration in mouse models. In this study we have investigated how IL‐21 affects the survival and cytotoxicity of human NK cells and modulates their expression of surface receptors and of the effector molecules granzyme B and perforin. In contrast to murine NK cells, where IL‐21 alone cannot sustain survival, IL‐21 and IL‐2 were equally efficient in sustaining survival of human NK cells. In the absence of other cytokines, IL‐21 had little effect on expression of a panel of surface receptors on human NK cells. However, IL‐21 synergized with IL‐2 to up‐regulate several surface receptors, including NKG2A, CD25, CD86 and CD69. The CD25+ CD86+ NK cells were CD56bright and were large and granular. Expression of the effector molecules perforin and granzyme A and B was up‐regulated by IL‐21 at both mRNA and protein levels. Furthermore, IL‐21 increased the cytotoxicity of NK cells against K562 target cells. These findings suggest that IL‐21 modulates NK cell activity through induction of intracellular effector molecules as well as modulation of surface receptor expression.
Long‐term sealing ability of Pulp Canal Sealer, AH‐Plus, GuttaFlow and Epiphany
Authors: Bouillaguet S. , Shaw L. , Barthelemy J. , Krejci I. , Wataha J. C. 
Published: November 2007

AbstractAim  To evaluate the long‐term sealing ability of four contemporary endodontic sealers [Pulp Canal Sealer (PCS), AH‐Plus, GuttaFlow and Epiphany] using a fluid filtration technique.Methodology  The palatal roots of 40 human maxillary molar teeth were selected and the root canal was prepared using a crown‐down technique (apical size 40, 6% taper). Roots were irrigated with 3% NaOCl, 17% EDTA solution and rinsed with distilled water. Canals were filled with either PCS, AH‐Plus, GuttaFlow or Epiphany using a single‐cone technique (n = 8). Twenty‐four hours after filling, the roots were connected to an automatic flow‐recording device (Flodec® System) filled with double‐distilled water under pressure (0.2 bar) to measure leakage. Flow rates were assessed at 6, 12 or 24‐h and after 1‐year of storage.Results  None of the materials fully prevented fluid flow. Fluid flow decreased after 6 h and decreased further after 12 h. After 24 h, PCS and AH‐Plus allowed significantly more fluid flow than GuttaFlow and Epiphany. After 1 year, PCS allowed significantly more fluid flow than the other materials. No significant changes in leakage occurred between 24 h and 1 year.Conclusions  GuttaFlow and Epiphany allowed less fluid movement along filled straight roots.
Regional variation in habitat–occupancy thresholds: a warning for conservation planning
Authors: Rhodes Jonathan R. , Callaghan John G. , McAlpine Clive A. , De Jong Carol , Bowen Michiala E. , Mitchell David L. , Lunney Daniel , Possingham Hugh P. 
Published: November 2007

SummaryAn important target for conservation planning is the minimum amount of habitat needed in a landscape to ensure the persistence of a species. Appropriate targets can be determined by identifying thresholds in the amount of habitat, below which persistence, abundance or occupancy declines rapidly. Although some studies have identified habitat thresholds, we currently have little understanding of the extent to which thresholds vary spatially. This is important for establishing whether we can apply the same planning targets across broad geographical regions.We quantified habitat–occupancy relationships for the koalaPhascolarctos cinereus(Goldfuss) in three study regions that span much of its geographical range. Standard and piecewise (broken‐stick/segmented) logistic regression were used to model linear and threshold habitat–occupancy relationships. We then used an information‐theoretic approach to test: (1) whether habitat–occupancy relationships were described better by threshold or linear models and (2) where threshold models were better, whether, and to what extent, threshold points varied among study regions.There was substantially greater support for the threshold than the linear models across a range of habitat qualities and landscape extents. The threshold models generally predicted a rapid decline in occupancy below the threshold points.Estimated threshold points varied, sometimes substantially, among study regions. This may relate to cross‐regional differences in habitat quality, demographic rates, and land‐use patterns. The role of habitat fragmentation is unclear.Synthesis and applications. Variation in threshold points among study regions suggests that we should be wary of using thresholds derived in one region for setting conservation planning targets in another. Rather, we should aim to set specific targets for individual locations (and species), while acknowledging the inherent uncertainties in these targets. This has implications for our ability to make general conservation prescriptions for widely distributed species. Future research should aim to develop generic models capable of predicting threshold responses across different landscapes and life‐history characteristics.
Kairomone traps: a tool for monitoring the invasive spruce bark beetle Dendroctonus micans (Coleoptera: Scolytinae) and its specific predator, Rhizophagus grandis (Coleoptera: Monotomidae)
Authors: Meurisse Nicolas , Couillien Daniel , Grégoire Jean‐Claude 
Published: November 2007

Summary

The Eurasian spruce bark beetle Dendroctonus micans is a major pest of spruce which is expanding its range in France, Turkey, England and Wales. Its monospecific predator Rhizophagus grandis has followed its prey naturally into most areas and since the 1960s has also been mass‐produced and released within newly infested locations. Assessing bark‐beetle presence at previously uninfested sites, or predator establishment after release or natural spread, currently depends on direct observation of D. micans brood chambers. This is a slow and unreliable process because bark‐beetle attacks are solitary, cryptic and occur on living trees. An effective trapping method would thus be most useful.
A synthetic lure for R. grandis was first field‐tested in release–recapture experiments. Release points were surrounded by one or two concentric rings of traps baited with either D. micans larval frass or with a blend of synthetic chemicals. Kairomone‐trapping using the synthetic lure was then tested in the field, monitoring R. grandis in 58 spruce stands in Belgium and France.
In the release–recapture experiments, up to 65% of the released predators were caught within 48 h. Catches with the synthetic lure and with prey frass were not significantly different.
Field‐trapping assays showed R. grandis establishment in 30 stands, including areas where the predator had been introduced artificially. Trapping was unsuccessful at the southern and western limits of D. micans’ range. Combined visual and trapping approaches identified 32 stands containing the predators, with two false negatives with the trapping method, compared to 19 for the visual surveys.
Unexpectedly, male and female D. micans adults were trapped in some cases. The combined approach identified 43 attacked stands, among which there were four false negatives with the trapping method and 11 with the visual surveys.
Synthesis and applications. To our knowledge, this is one of the first cases of using kairomone traps to monitor a predator after releases for biocontrol. Furthermore, because this predator is strictly prey‐specific, this technique also identifies stands colonized by D. micans bark beetles. Following inoculative predator releases, kairomone trapping could be used to survey for D. micans in areas under colonization or in European Union ‘Protected Zones’.
The impact of having a sibling with an intellectual disability: parental perspectives in two disorders
Authors: Mulroy S. , Robertson L. , Aiberti K. , Leonard H. , Bower C. 
Published: November 2007

AbstractBackground  The potential effects on other children when there is a child with intellectual disability (ID) in the family are being increasingly recognized. This study describes the impact of having a sibling with Down syndrome or Rett syndrome using a questionnaire completed by parents.Methods  The parents of 186 Western Australian children with Down syndrome and 141 Australian girls and women with Rett syndrome participated in the study. Patterns of reporting disadvantages and/or benefits were compared across a number of child and family variables (age, functional ability and birth order of the affected child, number of siblings and number of parents in the family home) and by socio‐economic status as measured by the index of relative socio‐economic disadvantage and by area of residence. Parents' responses to open‐ended questions about the benefits and/or disadvantages for siblings of their child were analysed for themes.Results  The majority of parents in the Rett syndrome and Down syndrome groups reported both disadvantages and benefits for siblings. In the Rett syndrome group, families from outer regional areas were the least likely to mention disadvantages and those with a smaller family more likely to note disadvantages. In both groups, more socio‐economically advantaged families were more likely to report disadvantages. In the Down syndrome group, benefits were also more commonly reported by parents who were socio‐economically advantaged, and by larger and two‐parent families. Major disadvantages for siblings centred around parental and personal time constraints, relationships and socializing, restrictions, parental emotion and burden of helping. Major benefits were related to personality characteristics.Conclusion  Parents identified both benefits and disadvantages to the siblings of their child with either Rett syndrome or Down syndrome. It is important that these findings are incorporated into any discussion around the impact on the family of a child diagnosed with an ID.
Improving memory span in children with Down syndrome
Authors: Conners F. A. , Rosenquist C. J. , Arnett L. , Moore M. S. , Hume L. E. 
Published: November 2007

AbstractBackground  Down syndrome (DS) is characterized by impaired memory span, particularly auditory verbal memory span. Memory span is linked developmentally to several language capabilities, and may be a basic capacity that enables language learning. If children with DS had better memory span, they might benefit more from language intervention. The present study evaluates a home‐based parent‐implemented intervention designed to improve auditory memory span in children with DS.Method  Sixteen children with DS, age 6–14, completed one or two 3‐month periods of memory training using overt cumulative rehearsal and auditory‐only procedures. Children were divided into two groups. Group 1 completed 3 months of memory training followed by 3 months of visual activities, followed by three more months of memory training. Group 2 had the opposite schedule. Before and after each 3‐month period, children came into the laboratory for memory assessment.Results  Children improved in training sessions and a small amount on digit span, the primary proximal outcome assessment measure. Digit span improvement was linked to the memory training, as indicated by control comparisons and correlations. Improvement was correlated with language comprehension and verbal working memory, but not with non‐verbal ability, age or home/behavioural variables. No improvement was evident on distal outcome measures (sentence memory and verbal working memory); however, a phonological similarity effect emerged coincidence with memory training, suggesting increased use of phonological codes in memory.Conclusions  Results suggest that some children with DS can improve their auditory verbal memory span with home‐based rehearsal training, at least in limited ways. Children with good language and verbal working memory skills may be the best candidates for this type of training, even though they may show only small improvements. Still, small improvements in a severely impaired function are noteworthy, and justify further investigation.
Atrial fibrillation: insights from clinical trials and novel treatment options
Authors: Blaauw Y. , Crijns H. J. G. M. 
Published: November 2007

Abstract. Blaauw Y, Crijns HJGM (University Hospital Maastricht, Maastricht, The Netherlands). Atrial fibrillation: insights from clinical trials and novel treatment options (Review).J Intern Med2007;262: 593–614.Atrial fibrillation (AF) is the most common encountered sustained arrhythmia in clinical practice. The last decade the result of large ‘rate’ versus ‘rhythm’ control trials have been published that have changed the current day practise of AF treatment. It has become clear that rate control is at least equally effective as a rhythm control strategy in ameliorating morbidity as well as mortality. Moreover, in each individual patient the risk of thromboembolic events should be assessed and antithrombotic treatment be initiated. There have also been great advances in understanding the mechanisms of AF. Experimental studies showed that as a result of electrical and structural remodelling of the atria, ‘AF begets AF’. Pharmacological prevention of atrial electrical remodelling has been troublesome, but it seems that blockers of the renin angiotensin system, and perhaps statins, may reduce atrial structural remodelling by preventing atrial fibrosis. Clinical studies demonstrated that the pulmonary veins exhibit foci that can act as initiator and perpetuator of the arrhythmia. Isolation of the pulmonary veins using radiofrequency catheter ablation usually abolishes AF. The most promising advances in the pharmacological treatment of AF include atrial specific antiarrhythmic drugs and direct thrombin inhibitors. In the present review we will describe the results of recent experimental studies, discuss the latest clinical trials, and we will focus on novel treatment modalities.
The role of tropical dry forest as a long‐term barrier to dispersal: a comparative phylogeographical analysis of dry forest tolerant and intolerant frogs
Authors: CRAWFORD ANDREW J. , BERMINGHAM ELDREDGE , CAROLINA POLANÍA S. 
Published: November 2007

AbstractWe used a comparative phylogeographical approach to investigate the origins of the disjunct wet forest biota of the Golfo Dulce region along the Pacific slope of Costa Rica. This region is isolated by Pacific dry forests north and south and isolated from Caribbean wet forests by mountains. We studied three sympatric lowland frog species in theCraugastor fitzingerispecies group that prefer wet forest but differ in their response to dry habitats. In dry forest,C. fitzingerican survive along streams whileC. crassidigitusandC. talamancaeare entirely absent. We collected samples from across the ranges of all three species, and obtained mitochondrial DNA sequence data from the COI and cytochromebgenes. We observed significant phylogeographical structure inC. crassidigitusandC. talamancae, but much less inC. fitzingeri, demonstrating that mountain barriers and dry forest habitat have reduced mitochondrial gene flow in the strictly wet‐forest species. Additionally, we discovered that the Golfo Dulce and Central Panama populations ofC. crassidigitusappear to have diverged in the Pliocene or earlier, suggesting that the dry forest separating these populations is old. Our phylogenetic analysis of 12 of approximately 16 species of theC. fitzingerispecies group suggests that the three lowland species are each other's closest relatives. Because of this shared phylogenetic history, we attribute the striking differences in phylogeographical structure to the different ecologies of the frogs. In summary, we find that what appear to be minor differences in the natural history of these three closely related species may profoundly impact the potential for dispersal, range size, and cladogenesis.
The population genomics of hepatitis B virus
Authors: SZMARAGD CAMILLE , BALLOUX FRANÇOIS 
Published: November 2007

AbstractHepatitis B virus (HBV) infection is considered as the fifth leading cause of death due to infectious diseases and has a worldwide prevalence. The particular geographical distribution of the eight previously defined genotypes of HBV suggests that the viral population is highly structured. The presence of such population structure is likely to affect the geographical distribution of polymorphisms involved in disease progression. In this study, we determined the structure of the HBV population using a clustering approach based on the observed allele frequencies at the polymorphic loci. We used all full‐genome sequences publicly available and obtained a significant clustering of the HBV population into four main clusters, strongly associated with the current classification into genotypes. One of these main clusters could itself be split into three well‐supported subclusters, highlighting the hierarchical nature of the population differentiation between HBV strains. The extremely clear‐cut subdivision of the HBV population further indicates that recombination in HBV is not as extensive as previously assumed.
The regulatory factor SipA provides a link between NblS and NblR signal transduction pathways in the cyanobacterium Synechococcus sp. PCC 7942
Authors: Salinas Paloma , Ruiz Diego , Cantos Raquel , Lopez‐Redondo Maria Luisa , Marina Alberto , Contreras Asunción 
Published: November 2007

SummaryCyanobacteria respond to environmental stress conditions by adjusting its photosynthesis machinery. When subjected to nutrient and high light stress, Synechococcus sp. PCC 7942 and other non‐diazotrophic cyanobacteria degrade their phycobilisome, the light‐harvesting complexes for photosynthesis. Phycobilisome degradation requires convergence of multiple signals onto the nblA gene. Despite considerable efforts to identify regulatory proteins involved in acclimation responses, the signal transduction mechanisms involved remain largely unknown. However, we show here that SipA, a protein that binds to the ATP‐binding domain of the histidine kinase NblS, counteracts the function of the response regulator NblR in acclimation to stress, and is also involved in downregulation of the nblA gene. The integrity of the HLR1 element overlapping PnblA‐1 and PnblA‐2 promoters is required for downregulation of the nblA gene. Induction by NblR is strongly dependent on DNA sequences located at least 44 bp upstream transcription initiation from PnblA‐2, and is also hampered by point mutations at HLR1. Genetic evidence of the antagonistic roles of NblR and SipA at regulation of the nblA gene, chlorosis and survival from stress is presented.
Induction of Host Protective Th1 Immune Response by Chemokines in Leishmania donovani‐infected BALB/c Mice
Authors: Dey R. , Majumder N. , Majumdar S. Bhattacharyya , Bhattacharjee S. , Banerjee S. , Roy S. , Majumdar S. 
Published: November 2007

AbstractThe resolution from leishmanial infection is dependent on the coordinated interactions between the components of the cell mediated immune system and the activation of T‐cell population into appropriate cytokine production and the activation of macrophages. Earlier reports established that C‐C chemokines particularly macrophage inflammatory protein (MIP)‐1α and macrophage chemoattractant protein (MCP)‐1 restrict the parasitic burden via the regulation of impaired protein kinase C (PKC) signalling and induction of free‐radical generation in murine leishmaniasis. This study explored the role of MIP‐1α and MCP‐1 in the induction of T helper 1 (Th1) immune response and suppression of T helper 2 (Th2) response in Leishmania donovani‐infected BALB/c mice. These chemokines induced the known pro‐inflammatory cytokine interleukin (IL)‐12 secretion and inhibited the secretion of anti‐inflammatory cytokines IL‐10 and transforming growth factor‐β in infected macrophages. Impaired antigen presentation capability of infected macrophages was also restored by the chemokine treatment. C‐C chemokine treatment resulted in reduced levels of mRNA expression of IL‐10, but increased levels of mRNA expression of IL‐12p40, interferon (IFN)‐γ, tumour necrosis factor‐α and inducible nitric oxide synthase in both liver mononuclear cells as well as in splenocytes, reflecting a switch of CD4+ differentiation from Th2 to Th1. Flow cytometric analysis of infected spleen cells suggested that C‐C chemokine treatment enhances the CD4+ T cells to produce increased levels of IFN‐γ. These studies hypothesize a promising immuno‐prophylactic effect of chemokines against leishmaniasis by induction of Th1 cytokine release imparting a long‐term resistance.
Protection of Mice against Mycobacterium tuberculosis Infection by Immunization with Aqueous Fraction of Triton X‐100‐soluble Cell Wall Proteins
Authors: Jeon B.‐Y. , Kim H.‐J. , Kim S.‐C. , Jo E.‐K. , Park J.‐K. , Paik T.‐H. , Kim S.‐J. , Cho S.‐N. 
Published: November 2007

AbstractThe aqueous fraction of Triton X‐100‐soluble proteins (TSP‐Aq) of Mycobacterium tuberculosis cell wall was reported to stimulate T‐cell responses in peripheral blood monocytes from tuberculosis (TB) patients and to induce Th1 cytokines, suggesting presence of protective antigens. In this study, therefore, we examined the protective efficacy of TSP‐Aq against M. tuberculosis infection in a mouse model. C57BL/6 mice were immunized with TSP‐Aq or culture filtrate proteins (CFP) mixed with incomplete Freund’s adjuvant or with BCG followed by i.v. challenge with M. tuberculosis H37Rv. TSP‐Aq induced strong interferon‐γ production by spleen cells, and mice immunized with TSP‐Aq antigens gave a significant reduction in M. tuberculosis CFU counts by 1.17–1.32 log10 CFU in the lungs and 1.31–2.08 log10 CFU in the spleen from 6 to 28 weeks. The degree of protection offered by TSP‐Aq was comparable to that of CFP and of the BCG vaccine. The results demonstrated that the TSP‐Aq antigens confer a significant level of protection against the growth of the organism in the lungs and spleen in a mouse model of TB and indicate that TSP contains major protective antigens of M. tuberculosis.