bluuebunny/crossref_metadata_2025_split huggingface dataset:
Reference values for B cell subpopulations from infancy to adulthood
Authors: Morbach H , Eichhorn E M , Liese J G , Girschick H J 
Published: September 2010

Summary
The composition of the peripheral blood lymphocyte compartment underlies developmental changes during ontogeny. Recently, several new B cell populations have been characterized which were suggested to develop in an age-dependent manner. However, age-dependent reference values for distinct B cell populations have rarely been reported. Therefore, we have characterized developmental changes in peripheral B cell populations from infancy to adulthood in order to define age-dependent reference values. Using a flow cytometric approach we analysed the frequencies as well as the absolute counts of naive, switched and non-switched memory B cells, CD27-negative memory B cells, transitional B cells as well as CD21lowCD38low B cells from neonates up to the age of 50 years. Most of the B cell subsets showed age-dependent developmental changes: while the peripheral B cell pool during infancy is characterized predominantly by transitional and naive B cells, the fraction of switched and non-switched memory B cells increases gradually with age. CD21lowCD38low B cells as well as plasmablasts do not exhibit developmental changes. In summary, we could demonstrate particular changes in the peripheral blood B cell compartment during ontogeny. This study provides reference values of different B cell subpopulations offering comparability for studies addressing disturbed peripheral B cell development in immunodeficiency, autoimmunity or B cell reconstitution following cell-depleting therapies.
Morphology of the root canal wall and arrangement of underlying dentinal tubules
Authors: WAKABAYASHI H. , MATSUMOTO K. , NAKAMURA Y. , SHERASUKA T. 
Published: September 2010

SummaryThe morphology of the root canal wall and the arrangement of the dentinal tubules underlying it were investigated in this study. Fifty clinically sound singlerooted human teeth were cut for longitudinal and transverse sections. After dissolving the organic components and removing the smear layer, the specimens were prepared for scanning electron microscopy. In the upper root level, semiglobular calcospherites were present on the canal wall and a convergent arrangement of the dentinal tubules was found on the transverse sections. At the mid root level, an irregular area of calification comprising of campressed calcospherites began to appear on the proximal wall and increased towards the apex. The transverse sections showed the crowding and convoluted arrangement of the dentinal tubules near the canal wall, in the proximal area. A correlation was noticed between the irregular calcification on the wall. These features were common in most of the specimens. This irregular secondary dentine does not appear to be pathological but physiological: associated with the normal ageing of the root.
Residue of gutta‐percha and a glass ionomer cement sealer following root canal retreatment
Authors: FRIEDMAN S. , MOSHONOV J. , TROPE M. 
Published: September 2010

SummaryA previous report indicates that root canals obturated with a new glass ionomer cement endodontic sealer (Ketac‐Endo, Espe, Germany) and laterally condensed gutta‐percha can be retreated by ultrasonic instrumentation. To address the possibility of Ketac‐Endo being used without condensation of gutta‐percha, the purpose of this study was to evaluate the efficacy of ultrasonic retreatment in canals obturated with single‐cone gutta‐percha and Ketac‐Endo. Thirty root canals were prepared in a standardized way to ISO size 40 and obturated with gutta‐percha and Ketac‐Endo. Either a size 40 gutta‐percha cone was used with and without lateral condensation, or a size 25 single cone, without condensation. After 14 days, the canals were retreated using chloroform and ultrasonic instrumentation. The roots were split vertically, and the amount of residual debris on the canal walls was assessed by three examiners using a dissecting microscope. Debris was recorded in the apical, middle and coronal canal levels according to a preset evaluation scale. The mean scores for each group were compared by ANOVA and Mann‐Whitney U‐test, with a 5% level of significance. In the roots obturated with lateral condensation the amount of residual debris in the coronal and middle canal levels was lower than in the other two groups, whereas in the apical level it was higher. Statistically, only the differences in the apical level were significant (P < 0.03). It was concluded that ultrasonic retreatment may be performed effectively in root canals obturated with single‐cone gutta‐percha and Ketac‐Endo.
Cemental tear: a case report
Authors: Stewart M. L. , McClanahan S. B. 
Published: September 2010

AbstractAim  To report a case of a cemental tear.Summary  A case is reported of a patient with a history of trauma, root canal treatment and retreatment procedures to eliminate recurring sinus tracts. An exploratory surgery, extraction, and biopsy resulted in a diagnosis of cemental tear.Key learning points  • The detachment of a fragment of cementum is described as a cemental tear.• Cemental tears have been reported in the periodontal literature associated with localized, rapid periodontal breakdown. Common causative factors are aging and traumatic occlusion but the exact aetiology is unknown.• Trauma may be considered as a potential aetiologic factor for cemental tears in addition to occlusal traumatism and aging.
Ex vivo biocompatibility tests of regular and white forms of mineral trioxide aggregate
Authors: Ribeiro D. A. , Matsumoto M. A. , Duarte M. A. H. , Marques M. E. A. , Salvadori D. M. F. 
Published: September 2010

AbstractAim  To examine the genotoxicity and cytotoxicity of regular and white mineral trioxide aggregate (MTA) ex vivo by the single‐cell gel (comet) assay and trypan blue exclusion test, respectively.Methodology  Aliquots of 1 × 104 Chinese hamster ovary cells were incubated at 37 °C for 3 h with grey and white forms of MTA at final concentrations ranging from 1 to 1000 μg mL−1. The negative control group was treated with vehicle control phosphate buffer solution for 3 h at 37 °C and the positive control group was treated with methyl metasulfonate (at 1 μg mL−1) for 1 h at 37 °C. After incubation, the cells were centrifuged at 180 g for 5 min and washed twice with fresh medium and resuspended with fresh medium. Each individual treatment was repeated three times consecutively to ensure reproducibility. Parameters from single‐cell gel (comet) and cytotoxicity assays were assessed by the Kruskal–Wallis nonparametric test.Results  Neither compounds produced genotoxic effects with respect to the single‐cell gel (comet) assay in all concentrations evaluated. In the same way, the dose–response relationships of all compounds tested at concentrations ranging from 1 to 1000 μg mL−1 on cell viability assessed by the trypan blue assay displayed no statistically significant differences (P > 0.05) for either endodontic material.Conclusions  Regular (grey) and white MTA are not genotoxins and do not induce cellular death.
Incidence and antimicrobial susceptibility of Porphyromonas gingivalis isolated from mixed endodontic infections
Authors: Jacinto R. C. , Gomes B. P. F. A. , Shah H. N. , Ferraz C. C. , Zaia A. A. , Souza‐Filho F. J. 
Published: September 2010

AbstractAim  To investigate the prevalence of Porphyromonas gingivalis in root canals of infected teeth with periapical abscesses and to investigate the antimicrobial susceptibility of this species to some frequently prescribed antibiotics.Methodology  Samples were obtained from 70 root canals of abscessed teeth. Microbial sampling, isolation and bacterial identification were accomplished using appropriate culture methods for anaerobic species. The antimicrobial susceptibility of the 20 strains of P. gingivalis isolated was determined by using the E‐test. The antimicrobial agents tested were amoxicillin, amoxicillin + clavulanate, azythromycin, benzylpenicillin, cephaclor, clindamycin, erythromycin, metronidazole and tetracycline.Results  A total of 352 individual strains, belonging to 69 different species, were isolated. Eighty three percent of the strains were strict anaerobes and 47.5% of the isolated bacteria were Gram‐negative. Porphyromonas gingivalis was found in 20 root canals and was most frequently found in symptomatic cases. Statistically, the presence of P. gingivalis was related to purulent exudates and pain on palpation (both P < 0.05). All P. gingivalis strains were sensitive to amoxicillin, amoxicillin + clavulanate, cephaclor, clindamycin, benzylpenicyllin, metronidazole and tetracycline. The lowest range of minimum inhibitory concentration (MIC) (0.026–0.125 μg mL−1) was observed against amoxicillin + clavulanate and clindamycin. The lowest MIC 90 was observed against clindamycin (0.064 μg mL−1). One strain was resistant to erythromycin and eight strains were resistant to azythromycin.Conclusion  Porphyromonas gingivalis pathogen is isolated with frequency from root canals of infected teeth with periapical abscesses. Amoxicillin, as well as amoxicillin–clavulanic acid and benzylpenicillin were effective against P. gingivalis.
Female home range size and the evolution of social organization in macropod marsupials
Authors: Fisher Diana O. , Owens Ian P. F. 
Published: September 2010

Summary1. Traditional explanations for interspecific variation in home range size are based almost exclusively on analysis of northern hemisphere eutherian mammals. These suggest that variation in body size is the most important factor, while climate and diet are less important. The generality of these explanations is tested using a novel database on macropod marsupials (kangaroos and allies).2. We found a 490‐fold difference in home range size and a 50‐fold difference in body weight amongst macropods. In agreement with studies on eutherians, female home range size was strongly correlated with body weight.3. However, unlike the pattern in eutherians, climate was more strongly associated with home range size than was body weight: annual rainfall explained more than half of the variation, while group size (6%) and population density (8%) were minor explanatory variables, and female body weight explained no further variation.4. When we used a phylogeny‐based comparative method, annual rainfall explained 32% of the variation and body size a further 16%.5. Sex differences in home range size were not explained by body size dimorphism, but were strongly related to rainfall and less strongly related to the degree of female home range overlap. Species with large sex differences in home range size lived in high‐rainfall habitats where female ranges were small.6. We suggest that climate has been a key factor in social evolution of macropods. In species inhabiting productive habitats, small female home ranges allow males to overlap with more females by increasing home range size. Males often compete for females by searching widely. In less productive habitats, males cannot further increase or defend their already large home ranges, resulting in similar‐sized ranges in both sexes. Where female home range overlap is high, males need not increase home ranges as much, but this effect is secondary to that of climate.7. In agreement with the theory that competitive searching by males is not necessarily related to body size, species with extreme size dimorphism had no sex difference in home range size, and species with extreme home range differences between the sexes showed no particular pattern of dimorphism.8. Variation among macropod species in home range size and social organization is more closely correlated with variation in habitat productivity, and is less related to body size, diet, density and group size, than predicted by eutherian‐based explanations.
Effects of food limitation and emigration on self‐thinning in experimental minnow cohorts
Authors: Dunham J. B. , Dickerson B. R. , Beever E. , Duncan R. D. , Vinyard G. L. 
Published: September 2010

Summary 1. The theory of food‐regulated self‐thinning (FST) for mobile animals predicts population density (N) to be an inverse function of mean body mass (W) scaled to an exponent (b), such that N = k W−b, where k is a constant. FST also predicts energy requirements (or energy flow) to remain constant over time (termed energetic equivalence) as losses to cohorts (e.g. emigration and mortality) are balanced by increased growth of surviving individuals. 2. To test these predictions, we analysed the dynamics of six experimental minnow cohorts. Replicate populations of fish were held under identical conditions with a constant and limited supply of food over a 126‐day period. Half of the cohorts were open to emigration, and half were closed so that fish could only be lost through starvation mortality. 3. Patterns of self‐thinning indicated non‐linear changes in population density and energy flow in relation to changes in mean body mass and time, respectively. Non‐linear patterns of self‐thinning were probably due to a delayed growth response to changes in population density effected through mortality and/or emigration. Contrary to results of similar experiments on other fish, emigration did not have a significant influence on the pattern of self‐thinning. 4. These results may be attributed to trophic interactions within cohorts and the importance of social behaviour to cohort dynamics. Both population density and energy flow in our experimental populations appeared to cycle, with episodes of starvation and mortality alternating with food recovery and weight gain, as predicted by recent models of stepwise die‐off and stunted growth in animal cohorts. 5. Most of the support for FST in mobile animals comes from observational data on mean body mass and population density. Potentially important mechanisms, including the manner in which individuals are lost or retained in populations, are usually not investigated directly. Such tests of FST can only provide equivocal support. Detailed observational study and controlled experiments are needed to understand casual mechanisms.
Relationships between sex ratio, climate and density in red deer: the importance of spatial scale
Authors: Mysterud Atle , Yoccoz Nigel G. , Stenseth Nils CHR. , Langvatn Rolf 
Published: September 2010

Summary1. Recently, contrasting evidence of density‐dependent offspring sex ratio variation in red deer (Cervus elaphusL.) has been presented.Kruuket al. (1999)reported that the proportion of male red deer born on the island of Rum, Scotland, each year declined with increasing population density and with winter rainfall, i.e. as nutritional stress in females increased. In contrast,Postet al. (1999a)reported increasing male‐biased offspring sex ratios in Hordaland, Norway, with both rising numbers of hinds and increasing values of the North Atlantic Oscillation (NAO), which they regarded an index of severe winters.2. Compared toPostet al. (1999a), we reanalysed sex ratio variation on a greatly extended data set, including four populations of Norwegian red deer, taking into account a finer population substructure.3. The proportion of male calves shot each autumn declined markedly as density increased in all four populations. The proportion of male calves shot each autumn increased significantly with an increasing NAO index in one of the four populations, but there was no residual effect of the NAO once the effect of snow depth (at low elevation) was controlled for (decreasingly male biased harvest with increasing snow depth).4. At the west coast of Norway, the NAO is positively correlated with temperature and precipitation. However, since temperatures in this region often are around 0 °C during winter, the relationship between the NAO and snow depth may be difficult to predict.5. An analysis of variation in snow depth revealed that snow depth was negatively correlated with the NAO at low altitudes (below 400 m), but this relationship was reversed at high altitudes giving a positive correlation between snow depth and the NAO. We therefore suggest that a high NAO index indicates favourable winter conditions for red deer, as red deer winter at low altitude, and since recent studies show that a high index of the NAO is generally positively correlated with body weight in red deer.6. Female red deer thus reared fewer sons as nutritional stress increased with increasing density and severity of climate in Norway, which is consistent with the birth sex ratios observed on Rum, Scotland.
Mouse population eruptions in New Zealand forests: the role of population density and seedfall
Authors: Choquenot David , Ruscoe Wendy A. 
Published: September 2010

Summary 1. Sporadically eruptive house mouse populations provide an opportunity to test ideas about how intrinsic and extrinsic factors interact to limit rodent populations. New Zealand house mouse populations inhabiting beech forests and associated mosaics erupt when autumn beech seedfall is high. We analysed 25 years of data on mouse density and beech seedfall from a beech and podocarp/hardwood forest mosaic in New Zealand to test the effects of mouse density, beech seedfall and rat density on rates of change in mouse abundance, estimated as the rate of change in a density index for sequential seasonal transitions (r). 2. For autumn to winter and winter to spring transitions, r was related to the magnitude of autumn seedfall and mouse density at the start of each transition, regardless of whether forest types were considered separately or together. For spring to summer and summer to autumn transitions, r was related to mouse density alone. Density dependence could reflect the influence of intrinsic social factors, intraspecific competition for food, or the effects of parasites, diseases or predators. 3. We modified a conceptual model of variation in rodent reproductive effort to derive a general model of how numerical responses to density‐independent increases in food availability, modified by density‐dependent mechanisms and extrinsic precursors to population increase, drive sporadic eruptions in the density of some rodent populations. For house mice in New Zealand, the numerical response to seedfall was modified by some unidentified density‐dependent mechanism(s) to generate sporadic eruptions. Extrinsic precursors to population increase appear to be important in other eruptive house mouse populations. 4. House mouse density in beech forest was more volatile than in podocarp/hardwood forest, maximum rates of increase and decrease being higher in the former. Density tended to be higher in podocarp/hardwood forest when overall density was low, and higher in beech forest when overall density was high. This suggests that between eruptions, mice persist in podocarp/hardwood forest at higher densities than in adjoining beech forest.
Butterfly numbers and weather: predicting historical trends in abundance and the future effects of climate change
Authors: Roy D. B. , Rothery P. , Moss D. , Pollard E. , Thomas J. A. 
Published: September 2010

Summary

The effect of weather on the size of British butterfly populations was studied using national weather records and the Butterfly Monitoring Scheme (BMS), a national database that has measured butterfly abundance since 1976.
Strong associations between weather and population fluctuations and trends were found in 28 of 31 species studied. The main positive associations were with warm summer (especially June) temperature during the current and previous year, low rainfall in the current year and high rainfall in the previous year. Most bivoltine species benefited from warm June weather in the current year, three spring species and two that overwinter as adults benefited from warm weather in the previous summer, and most species with moist or semi‐shaded habitats increased following high rainfall and cooler weather in the previous year.
Simple models incorporating weather variables and density effects were constructed for each species using the first 15 years’ population data (1976–90). These fitted the observed data for that period well (median R2 = 70%). Models were less good at predicting changes in abundance over the next 7 years (1991–97), although significant predictive success was obtained.
Parameter values of models were then adjusted to incorporate the full 22‐year data‐run. For the eight species whose models had best predicted population changes or fitted the data well (R2 > 85%), models were run from 1767 to 1997, using historical weather records, to ‘predict’ trends in abundance over the past two centuries. For three species it was possible to compare predicted past trends with contemporary accounts of abundance since 1800. In each case, the match between predictions and these qualitative assessments was good.
Models were also used to predict future changes in abundance, using three published scenarios for climate change. Most, but not all, species are predicted to increase in the UK under warmer climates, a few species stayed stable, and only one species – the agricultural pest Pieris brassicae (Cabbage White) – is predicted to decline.
Habitat heterogeneity affects population growth in goshawkAccipiter gentilis
Authors: Krüger Oliver , Lindström Jan 
Published: September 2010

SummaryThe concept of site‐dependent population regulation combines the ideas of Ideal Free Distribution‐type of habitat settlement and density dependence in a vital rate mediated by habitat heterogeneity. The latter is also known as habitat heterogeneity hypothesis. Site‐dependent population regulation hypothesis predicts that increasing population density should lead to inhabitation of increasingly poor territories and decreasing per capita population growth rate. An alternative mechanism for population regulation in a territorial breeding system is interference competition. However, this would be expected to cause a more even decrease in individual success with increasing density than site‐dependent regulation.We tested these ideas using long‐term (1975–99) population data from a goshawkAccipiter gentilispopulation in Eastern Westphalia, Germany.Goshawk territory occupancy patterns and reproduction parameters support predictions of site‐dependent population regulation: territories that were occupied more often and earlier had a higher mean brood size. Fecundity did not decrease with increasing density in best territories.Using time‐series modelling, we also showed that the most parsimonious model explaining per capita population growth rate included annual mean habitat quality, weather during the chick rearing and autumn period and density as variables. This model explained 63% of the variation in per capita growth rate. The need for including habitat quality in the time‐series model provides further support for the idea of site‐dependent population regulation in goshawk.