bluuebunny/crossref_metadata_2025_split huggingface dataset:
Large‐scale expansion of rat CD4+ CD25+ Treg cells in the absence of T‐cell receptor stimulation
Authors: Beyersdorf Niklas , Balbach Karen , Hünig Thomas , Kerkau Thomas 
Published: August 2006

SummaryT‐cell receptor (TCR) stimulation is both central to homeostatic maintenance of CD4+ CD25+ regulatory T cells (Treg cells) in vivo and a prerequisite for the initiation of suppression by Treg cells, both in vivo and in vitro. However, TCR‐independent stimulation of Treg cells, e.g. with superagonistic CD28‐specific monoclonal antibodies (CD28‐SA), not only expands these cells in vivo but, as we show here, also mediates large‐scale expansion of rat Treg cells in vitro. Interestingly, CD28‐SA stimulation plus interleukin (IL)‐2 was even superior to conventional costimulation plus IL‐2 in promoting Treg cell growth in vitro. Despite their highly activated phenotype suppression by Treg cells expanded in the absence of TCR stimulation remained fully dependent on TCR‐triggering for initiation and cell contact was required to exert suppression. With regard to the regulation of suppression by CD28 stimulation we observed that neither the presence of a conventional anti‐CD28 monoclonal antibody nor a CD28‐SA generally rendered conventional T cells resistant to suppression by preactivated Treg cells. Taken together, we provide a novel protocol for long‐term propagation of Treg cells in vitro and our data are the first to reveal a difference in the signals required for activation and expansion of Treg cells and those, involving the TCR, necessary for the initiation of suppression.
Pulpal anaesthesia for mandibular permanent first molar teeth: a double‐blind randomized cross‐over trial comparing buccal and buccal plus lingual infiltration injections in volunteers
Authors: Meechan J. G. , Kanaa M. D. , Corbett I. P. , Steen I. N. , Whitworth J. M. 
Published: August 2006

AbstractAim  To compare the efficacy of buccal and buccal plus lingual infiltration anaesthesia for permanent mandibular first molars.Methodology  Thirty one healthy adult volunteers received each of the following methods of anaesthesia for a mandibular first molar tooth in a randomised order, 1) Buccal infiltration of 1.8 mL and needle penetration lingually. 2) Buccal infiltration of 0.9 mL, plus lingual infiltration of 0.9 mL. Two percent lidocaine with 1:100,000 epinephrine was used. Electrical pulp testing was performed before, and every 2 minutes for 30 minutes after injection. A successful outcome was recorded as the absence of pulp sensation on two or more consecutive maximal pulp tester stimulations (80 μA). Injection discomfort was assessed using visual analogue scales. Data were compared with McNemar and Wilcoxon Signed Ranks tests.Results  Buccal infiltration was successful in 38.7% of cases compared to 32.3% after combined infiltrations; the difference was not significant (P = 0.63). Buccal infiltration produced more episodes of no response to maximum stimulation than buccal and lingual infiltrations (129 and 114 respectively), this difference was not significant (P = 0.11). Peak anaesthetic effect occurred around 10–14 minutes after injection. There was no difference in injection discomfort between buccal injections of 0.9 mL and 1.8 mL of solution (P = 0.90). Lingual injection was more uncomfortable than lingual penetration (P = O.O02).Conclusions  Buccal and buccal plus lingual infiltrations did not differ in their efficacy in producing anaesthesia of permanent first molar teeth.
Root canal treatment in Denmark is most often carried out in carious vital molar teeth and retreatments are rare
Authors: Bjørndal L. , Laustsen M. H. , Reit C. 
Published: August 2006

AbstractAim  To study the reasons given by a representative sample of Danish general dental practitioners (GDPs) for undertaking root canal treatment and, to investigate their confidence in performing root canal treatment on molar teeth.Methodology  A questionnaire was sent to 600 Danish GDPs randomly selected from the roster of the Danish Dental Association. They were asked to recall various factors about their experience of the last root filling they completed, including the reason for treatment and the pulp diagnosis. Self‐assessments on 100‐mm visual analogue scales (VAS) were reported concerning the confidence in performing root canal treatment of a molar. End‐point definitions were ‘very easy’ (0) and ‘very difficult’ (100), respectively. Time reports of molar treatments were given in categorized groups.Results  The most frequent reason for performing root canal treatment was caries within the tooth involved (55%). The majority of treatments involved teeth with vital pulps (54%). Retreatments were carried out in 2% of the cases. The confidence in performing root canal treatment varied but was relatively high, expressed as VAS‐values below 50. The creation of an aseptic working field was regarded as the most difficult procedure followed by root canal preparation. Fifty‐six percent of the responders stated a time frame of 46–75 min to complete root filling in a molar tooth.Conclusions  Root canal treatment in Denmark was reported to be undertaken most often because of caries. Treatment was typically performed in molar teeth with vital pulp. Even though apical periodontitis was frequently noted in root filled teeth, retreatments were rare. From a subjective perspective root canal treatment was not considered to be very difficult and was carried out relatively rapidly.
Haemostatic agents used in periradicular surgery: an experimental study of their efficacy and tissue reactions
Authors: Von Arx T. , Jensen S. S. , Hänni S. , Schenk R. K. 
Published: August 2006

AbstractAim  To evaluate the haemostatic efficacy and the histologic tissue responses after the application of different haemostatic agents used in periradicular surgery.Methodology  The study was conducted in the calvarium of six rabbits. Standardized bone defects (diameter 4 mm) were trephined, and different haemostatic agents were applied and compared with control defects: bone wax (left for 10 min), Stasis® (ferric sulphate, left for 5 s), ExpasylTM (aluminium chloride, left for 2 min and left permanently in situ), and a combination of ExpasylTM (2 min) and Stasis® (5 s). The sites were photographed before the application and after the removal of the haemostatic agents. Three independent examiners judged the initial and final bleeding (on the photographs) using a bleeding score for each site and treatment. The results were compared using Wilcoxon's signed rank test. For the histologic analysis, three animals were killed after 3 weeks and three animals after 12 weeks. Transverse, nondecalcified sections were stained with combined basic fuchsin and toluidine blue for descriptive histology.Results  The most efficient haemorrhage control was provided by ExpasylTM in combination with Stasis® and by ExpasylTM alone, whereas bone wax had the weakest bleeding reduction effect. The histologic analysis after 3 weeks demonstrated an inflammatory and foreign body tissue response towards all haemostatic agents. At 12 weeks, this tissue response was less pronounced but still present in sites treated with bone wax or ExpasylTM. In general, the inflammatory tissue reactions were limited to the bone defects, and never extended into the surrounding tissues.Conclusions  ExpasylTM alone or in combination with Stasis® appeared to be the most efficient of tested agents to control the bleeding within the bony defects created in a rabbit calvarium model.
Effects of luting agent and thermocycling on bond strengths to root canal dentine
Authors: Bitter K. , Meyer‐Lueckel H. , Priehn K. , Kanjuparambil J. P. , Neumann K. , Kielbassa A. M. 
Published: August 2006

AbstractAim  To investigate the effects of luting agent and thermocycling on bond strengths to root canal dentine.Methodology  Extracted maxillary canines (n =144) were root filled and divided into six groups of 24 teeth each. Fibre posts (FRC Postec) were inserted using six luting agents: Panavia F, Multilink, Variolink II, PermaFlo DC, RelyX Unicem and Clearfil Core. Each root was sliced into six discs (thickness 1 mm) representing the coronal, middle and apical part of the root canal. Push‐out tests were performed 24 h after post insertion (n = 12) as well as after thermocycling (5000×; 5–55 °C, 30 s) (n = 12). Statistical analysis was conducted using analysis of variance (anova) followed by post‐hoc comparisons (Tukey‐B). The influence of thermocycling on bond strengths was investigated for each material and region separately using t‐tests.Results  The bond strengths were significantly affected by the luting agent (P < 0.001), the root position (P = 0.003) and thermocycling (P < 0.001; three‐way anova). RelyX had significantly higher bond strengths compared with all other materials (P < 0.05; Tukey‐B). The apical region of the root canal had significantly higher bond strengths compared with the middle and coronal region (P < 0.05; Tukey‐B). After thermocycling for RelyX a significant increase in bond strengths was detected for the middle and apical region (P < 0.01; t‐test, Bonferroni factor 18).Conclusions  Bond strengths were affected significantly by luting agent and root position. RelyX had higher bond strengths compared with other materials. The apical region of the canals was characterized by significantly higher bond strengths.
Cytokine‐induced prostaglandin E2 production and cyclooxygenase‐2 expression in dental pulp cells: downstream calcium signalling via activation of prostaglandin EP receptor
Authors: Chang M.‐C. , Chen Y.‐J. , Tai T.‐F. , Tai M.‐R. , Li M.‐Y. , Tsai Y.‐L. , Lan W.‐H. , Wang Y.‐L. , Jeng J.‐H. 
Published: August 2006

AbstractAim  To determine whether (i) proinflammatory cytokines stimulate prostaglandin E2 (PGE2) production and cyclooxygenase (COX) gene expression in dental pulp cells, and (ii) pulp cells that express different prostaglandin E2 receptor (EP) isoforms and their activation by PGE2 leads to downstream Ca2+ signalling.Methodology  Cultured human dental pulp cells were exposed to interleukin (IL)‐1β and tumour necrotic factor‐alpha (TNF‐α). The expression of COX‐1 and COX‐2 was measured with reverse transcriptase‐polymerase chain reaction (RT‐PCR). The production of PGE2 was measured using an enzyme‐linked immunosorbent assay. Expression of prostaglandin EP receptor isoforms was studied by RT‐PCR, whereas fura‐2 fluorescence was used to measure calcium mobilization. The Kruskal–Wallis test and Wilcoxon sum rank test with Bonferroni correction were used for statistical analysis.Results  Interleukin‐1β and TNF‐α stimulate PGE2 production of human dental pulp cells (P < 0.05). IL‐1β stimulated the COX‐2 but not COX‐1 mRNA expression. Pulp cells express mainly EP2, EP3 and EP1 receptors as analysed by RT‐PCR. PGE2 (0.25–2 μmol L−1) stimulated the Ca2+ mobilization as indicated by increase in fura‐2 fluorescence.Conclusions  Interleukin‐1β and TNF‐α may stimulate PGE2 production in dental pulp cells. Activation of prostaglandin EP receptors in dental pulp cells by PGE2 may induce Ca2+ signalling to regulate cellular biological activity during inflammation.
Diagnostic value of computed tomography in re‐treatment of root fillings in maxillary molars
Authors: Huumonen S. , Kvist T. , Gröndahl K. , Molander A. 
Published: August 2006

AbstractAim  To compare the diagnostic information and radiation dose between intraoral radiography and computed tomography (CT) in re‐treatment decision making concerning root fillings in maxillary molars.Methodology  Thirty‐nine root‐filled maxillary molars with suspected apical periodontitis were examined with two intraoral periapical radiographs and CT. Presence of periapical lesion/s per tooth and root were analysed for both techniques. In addition, in the CT images, the number of root canals, erosion, or perforation of cortical bone plates, and the distance between palatal root and cortical bone plates were evaluated. Radiation dose for CT was registered and calculated; and that of periapical radiographs used as reported previously (Ekestubbe et al. 2004).Results  Periapical radiographs revealed periapical lesions in 33 teeth compared with 38 on CT images. A lesion of any root was detected more often with CT. The mesiobuccal root had two root canals in 30 teeth of which 27 of the MB2 canals were not filled, and 22 roots with an unfilled canal were associated a periapical lesion. Distances to palatal root, from the buccal and palatal cortex were measured in CT and varied between 5.0–12.0 mm and 0–4.0 mm, respectively. Based on the radiographic information, a variety of treatment alternatives were suggested. Mean effective dose of periapical radiographs was 0.02 mSv and that of CT 0.055 mSv.Conclusions  Computed tomography may give important information in re‐treatment decision when considering root fillings in maxillary molars. The radiation dose should be considered individually.
Differential patterns of morphological and molecular hybridization between Fraxinus excelsior L. and Fraxinus angustifolia Vahl (Oleaceae) in eastern and western France
Authors: FERNANDEZ‐MANJARRES J. F. , GERARD P. R. , DUFOUR J. , RAQUIN C. , FRASCARIA‐LACOSTE N. 
Published: August 2006

AbstractWe examined large‐scale patterns of morphology, genetic structure and ecological correlates of Fraxinus excelsior and the closely related species Fraxinus angustifolia in France, in order to determine the degree of hybridization between them. We sampled 24 populations in two putative hybrid zones (Loire and Saône), and five control populations of each species. We measured foliar characteristics of adult trees and used five nuclear microsatellites as molecular markers. Canonical discriminant analysis indicated that the two species differ in morphology, but that intermediate types are common in the Loire region but less frequent in the Saône region. Bayesian population assignment identified one F. angustifolia and two F. excelsior gene pools. Most Loire individuals clustered genetically with the F. angustifolia gene pool. In contrast, the Saône region presented individuals belonging mostly to F. excelsior pools, although the F. angustifolia type was frequent in certain populations. The lowest FST values were found between the Loire and F. angustifolia controls that also exhibited no significant isolation by distance. The proportion of the F. angustifolia gene pool in each locality was negatively correlated with winter temperatures, suggesting that a cold climate may be limiting. Hybridization is probably favoured by the intermediate climatic conditions in the Loire region that allow both species to occur, but is somewhat hampered by the harsher winters in the Saône area where morphological introgression has apparently not yet occurred.
Comparative phylogeography of the Veronica alpina complex in Europe and North America
Authors: ALBACH DIRK C. , SCHÖNSWETTER PETER , TRIBSCH ANDREAS 
Published: August 2006

AbstractThe Veronica alpina complex comprises eight species of alpine habitats over a wide range of mountain systems in the Northern Hemisphere. The occurrence of sympatric species in the European and North American mountain systems allowed us not only to investigate the effect of the ice ages on intraspecific phylogeographical patterns and genetic diversity in different continents of the Northern Hemisphere, but also to compare these patterns in closely related species. Plastid DNA trnL‐F sequences and AFLP (amplified fragment length polymorphism) fingerprints were used to infer the phylogenetic history of the group and phylogeographical patterns within species. Hybrid origin of tetraploid eastern North American V. wormskjoldii from western North American V. nutans (= V. wormskjoldii s.l.) and Eurasian V. alpina is suggested. A number of phylogeographical groups have been found both in V. alpina from Europe and in V. nutans from western North America. Phylogeographical substructuring in the Alps is inferred for V. alpina but not for V. bellidioides, which is moreover characterized by an overall very low genetic diversity. Western North American V. cusickii is much more genetically diverse than its sympatric relative, V. nutans, an effect that is likely due to differences in the breeding system. Populations of V. nutans are differentiated into three groups, those from the Cascades and from the southern and the northern Rocky Mountains. Genetic diversity seems to be higher in the North American V. nutans than in the morphologically and ecologically similar European V. alpina. A possible scenario to explain this pattern is suggested.
Incomplete cryptic speciation between intertidal and subtidal morphs of Acrocnida brachiata (Echinodermata: Ophiuroidea) in the Northeast Atlantic
Authors: MUTHS D. , DAVOULT D. , GENTIL F. , JOLLIVET D. 
Published: August 2006

AbstractThe brittle‐star Acrocnida brachiata (Montagu) lives in sandy‐bottom habitat of both intertidal and subtidal zones along the coasts of the northwestern Europe. An allozyme frequency‐based survey (five enzyme loci) was combined with a mitochondrial (mt) COI haplotype analysis (598‐bp sequences) on 17 populations to trace back past colonization pathways from the actual population structure of the species. Both genetic markers display a sharp genetic break between intertidal (clade I) and subtidal populations (clade S). This break corresponds to an allele frequency inversion at three enzyme loci (Hk, Pgm and Pgi) and a deep divergence of about 20% in mtCOI sequences between most of the intertidal populations and other samples. The geographic distribution of clade I seems to be more restricted than clade S as it is absent from the intertidal of the eastern English Channel and North Sea and may be replaced by clade S in south Brittany. Applying previously published rates of mutation, divergence between the two clades is estimated to pre‐date 5 million years ago and may be due to allopatric speciation processes at the Mio–Pliocene transition. The occurrence of putative hybrids in a few localities, however, suggests incomplete cryptic speciation with secondary contact zones. The relative importance of colonization history vs. habitat specialization are discussed in the light of neutral evolution as tested from mtCOI gene sequences. While differential selection seems to have contributed little to the separation of the lineages, it may have played a role in the emergence of adaptive polymorphisms in the hybrid zone. Furthermore, congruent spatial patterns of differentiation were observed in both clades suggesting a recent increase in population size. These findings are in agreement with a recent expansion of the populations during or after the formation of the English Channel, from a southern refuge for the subtidal clade whereas the intertidal clade may have persisted further north. As previously suspected for a species with a very short pelagic larval phase, contemporary gene flow between distant or adjacent populations appears to be extremely reduced or even absent.
Evolution of rattlesnakes (Viperidae; Crotalus) in the warm deserts of western North America shaped by Neogene vicariance and Quaternary climate change
Authors: DOUGLAS MICHAEL E. , DOUGLAS MARLIS R. , SCHUETT GORDON W. , PORRAS LOUIS W. 
Published: August 2006

AbstractDuring Pleistocene, the Laurentide ice sheet rearranged and diversified biotic distributions in eastern North America, yet had minimal physical impact in western North America where lineage diversification is instead hypothesized to result from climatic changes. If Pleistocene climatic fluctuations impacted desert species, the latter would reflect patterns of restricted gene flow concomitant with indications of demographic bottlenecks. Accordingly, molecular evidence for refugia should be present within these distributions and for subsequent range expansions as conditions improved. We sought answers to these questions by evaluating mitochondrial DNA (mtDNA) sequences from four species of rattlesnakes [Crotalus mitchellii (speckled rattlesnake), Crotalus cerastes (sidewinder), Crotalus tigris (tiger rattlesnake), Crotalus ruber (red diamond rattlesnake)] with distributions restricted to desert regions of southwestern North America. We inferred relationships using parsimony and maximum likelihood, tested intraspecific clades for population expansions, applied an isolation‐with‐migration model to determine bi‐directional migration rates (m) among regions, and inferred divergence times for species and clades by applying a semiparametric penalized likelihood approach to our molecular data. Evidence for significant range expansion was present in two of eight regions in two species (Crotalus mitchellii pyrrhus, C. tigris region north). Two species (C. cerastes, C. mitchellii) showed a distribution concomitant with northward displacement of Baja California from mainland México, followed by vicariant separation into subclades. Effects of Pleistocene climate fluctuations were found in the distributions of all four species. Three regional diversification patterns were identified: (i) shallow genetic diversity that resulted from Pleistocene climatic events (C. tigris, C. ruber); (ii) deep Pleistocene divisions indicating allopatric segregation of subclades within refugia (C. mitchellii, C. cerastes); and (iii) lineage diversifications that extended to Pliocene or Late Miocene (C. mitchellii, C. cerastes). Clade‐diversifying and clade‐constraining effects impacted the four species of rattlesnakes unequally. We found relatively high levels of molecular diversification in the two most broadly distributed species (C. mitchellii, C. cerastes), and lower levels of genetic diversification in the two species (C. tigris, C. ruber) whose ranges are relatively more restricted. Furthermore, in several cases, the distributions of subspecies were not congruent with our molecular information. We suggest regional conservation perspectives for southwestern deserts cannot rely upon subspecies as biodiversity surrogates, but must instead employ a molecular and deep historical perspective as a primary mechanism to frame biodiversity reserves within this region.
An empirical verification of population assignment methods by marking and parentage data: hatchery and wild steelhead (Oncorhynchus mykiss) in Forks Creek, Washington, USA
Authors: HAUSER L. , SEAMONS T. R. , DAUER M. , NAISH K. A. , QUINN T. P. 
Published: August 2006

AbstractAssignment tests are increasingly applied in ecology and conservation, although empirical comparisons of methods are still rare or are restricted to few of the available approaches. Furthermore, the performance of assignment tests in cases with low population differentiation, violations of Hardy–Weinberg equilibrium and unbalanced sampling designs has not been verified. The release of adult hatchery steelhead to spawn in Forks Creek in 1996 and 1997 provided an opportunity to compare the power of different assignment methods to distinguish their offspring from those of sympatric wild steelhead. We compared standard assignment methods requiring baseline samples (frequency, distance and Bayesian) and clustering approaches with and without baseline information, using six freely available computer programs. Assignments were verified by parentage data obtained for a subset of returning offspring. All methods provided similar assignment success, despite low differentiation between wild and hatchery fish (FST = 0.02). Bayesian approaches with baseline data performed best, whereas the results of clustering methods were variable and depended on the samples included in the analysis and the availability of baseline information. Removal of a locus with null alleles and equalizing sample sizes had little effect on assignments. Our results demonstrate the robustness of most assignment tests to low differentiation and violations of assumptions, as well as their utility for ecological studies that require correct classification of different groups.