bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of ETV6‐NTRK in classical, cellular and mixed subtypes of congenital mesoblastic nephroma
Authors: Anderson J , Gibson S , Sebire N J 
Published: March 2006

Aim:  Congenital mesoblastic nephroma (CMN) is the commonest renal tumour of infancy, with classical, cellular and mixed histological subtypes described. A specific ETV6‐NTRK3 fusion‐gene product is reported in association with the cellular variant. The aim was to investigate the relationship between the presence of this product and morphological phenotype using paraffin‐embedded archival material.Methods and results:  Cases of CMN from a single centre during a 15‐year period (1989–1994) were identified, anonymized and blindly classified using morphological criteria. RNA was extracted from frozen and paraffin sections for both conventional reverse transcriptase‐polymerase chain reaction (RT‐PCR) and quantitative real‐time RT‐PCR. Fifteen samples were analysed; two were non‐informative and three expressed ETV6‐NTRK3 using both techniques, two showing similar expression, whilst one showed expression two orders of magnitude lower, from a cellular tumour. All fusion positive cases were previously classified as cellular subtype. Six patients had mixed‐subtype tumours in which the cellular components, morphologically indistinguishable from cellular tumours, were fusion negative, as were all classical cases.Conclusions:  Real‐time PCR Taqman assays, using both fixed and frozen tissue, provide highly reproducible detection and quantification of fusion transcript expression. Differences in expression levels may explain previous conflicting data on fusion gene detection in these tumours.
Natural and anthropogenic variation in coarse wood among and within lakes
Authors: MARBURG ANNA E. , TURNER MONICA G. , KRATZ TIMOTHY K. 
Published: March 2006

SummaryResidential development is often concentrated near aquatic ecosystems and understanding riparian–littoral zone interactions is therefore critical for assessing its ecological effects.Introduction of wood from riparian forests into the littoral zone, where it becomes habitat for aquatic organisms, is an important, but poorly understood, process. We related the density of littoral coarse wood both among and within 45 lakes in Vilas County, Wisconsin, USA, to forest structure, abiotic drivers and land use.Among all lakes and among a subset of low‐development lakes, the best predictor of the density of littoral coarse wood was the density of riparian coarse wood. At the within‐lake (site) level, two alternative models explain variability in coarse wood abundance: as a function of exposure to wind and amount of riparian coarse wood or as a function of exposure to wind and land‐use intensity.Both among and within lakes, areas more modified by humans had a lower density of littoral coarse wood. Conversely, areas with little (current) human impact were tremendously variable; some sites and lakes had abundant wood and others had virtually none.Contrary to previous studies, there was no relationship between living trees and coarse wood density, suggesting that riparian and littoral coarse wood densities may be strongly influenced by past disturbance, both human and natural.This study highlights the importance of cross boundary subsidies in understanding the impact of development on ecosystems. The concentration of residential development at the boundary between terrestrial and aquatic ecosystems appears to reduce the flow of coarse wood from forests to lakes. Loss of this resource may have negative consequences for lake biota and the aquatic food web.
Strategies of Solanum carolinense for regulating maternal investment in response to foliar and floral herbivory
Authors: WISE MICHAEL J. , CUMMINS JEREMIAH J. 
Published: March 2006

Summary
The series of steps used to regulate a plant's investment in reproduction in response to environmental stresses is a life‐history strategy critical to maximizing fitness. We investigated how the andromonoecious herb Solanum carolinense regulates its maternal investment in response to stress from foliar and floral herbivory.
Most of the variation among S. carolinense individuals (ramets) in maternal investment occurred during the initiation of flower‐bud primordia, with ramets initiating between 9 and 167 flower buds.
In response to simulated floral herbivory, S. carolinense regulated maternal investment by decreasing the abortion rate of flower buds, increasing the ratio of perfect to male flowers and decreasing the rate of fruit abortion.
In response to foliar herbivory, the plants increased the rate of fruit abortion and decreased allocation to perennial root growth.
Some individuals specialized at regulating during early phenological stages, others specialized at later regulation, and there appeared to be trade‐offs between these strategies.
Because most plants must cope with multiple stresses that occur at different times in their phenology, such trade‐offs suggest the presence of adaptive constraints. In particular, a plant's ability to tolerate damage by one species of herbivore may be constrained by the cost of lower tolerance of the damage caused by the other herbivores that feed on the plant.
Neighbourhood composition determines growth, architecture and herbivory in tropical rain forest tree seedlings
Authors: MASSEY FERGUS P. , MASSEY KATE , PRESS MALCOLM C. , HARTLEY SUE E. 
Published: March 2006

Summary
Interspecific and intraspecific competition in seedling banks may be important determinants of regeneration success in some groups of canopy trees, e.g. dipterocarps in south‐east Asian tropical rain forests, and the outcomes of these competitive interactions may contribute to the maintenance of the high levels of plant diversity.
We present the results of an experiment examining the effects of seedling bank diversity within canopy gaps on seedling growth, architecture and levels of insect herbivore defoliation over 18 months. Within each of six experimental canopy gaps, we planted two conspecific blocks of Shorea leprosula (Dipterocarpaceae) seedlings and two heterospecific blocks of S. leprosula seedlings amongst four other dipterocarp species with differing growth rates and palatability to herbivores.
The growth allocation patterns of S. leprosula differed according to whether they were planted among conspecifics or heterospecifics. Although S. leprosula seedlings grew taller in conspecific stands, their above ground biomass did not differ between planting treatments, due to increased branching and leaf area in seedlings in the heterospecific stands.
Shorea leprosula displayed the lowest levels of antiherbivore defences and sustained the greatest levels of defoliation of all species studied. Despite an increase of almost 60% in leaf damage in conspecific vs. heterospecific stands, neither biomass nor survival of S. leprosula seedlings differed between stands over the 18‐month growth period.
The important effects of neighbourhood composition on the growth and herbivory of S. leprosula seedlings, suggest that diversity of seedling banks can be an important determinant of regeneration success and, thus, forest dynamics. Neighbourhood composition may have similar impacts on competitive outcomes and biomass allocation patterns in other ecological communities.
Lower serum concentration of matrix metalloproteinase‐3 in the acute stage of myocardial infarction
Authors: SAMNEGÅRD A. , SILVEIRA A. , TORNVALL P. , HAMSTEN A. , ERICSSON C.‐G. , ERIKSSON P. 
Published: March 2006

Abstract.Objectives.  The importance of matrix metalloproteinases (MMPs) in the progression and rupture of the atherosclerotic plaque is gaining increasing recognition but the mechanisms are not yet fully understood. The aim of this study was to investigate the significance of MMP‐3 in the acute phase of myocardial infarction (MI) and the influence of the −1612 5A/6A MMP‐3 gene promoter polymorphism on serum MMP‐3 concentration.Subjects.  One‐hundred and sixty‐four patients admitted with ST‐elevation MI and receiving thrombolysis treatment were included in this study. Serum MMP‐3 was analysed at admission, after 48 h and at 3 months.Results.  Serum MMP‐3 concentration was significantly increased at 3 months when compared with admission and 48 h (19.5 ng mL−1 [14.4–24.7] vs. 15.5 ng mL−1 [10.5–21.8] at admission, P < 0.001; and 14.7 ng mL−1 [9.9–23.8] at 48 h, P < 0.001). Furthermore, we found the −1612 5A/6A polymorphism to influence the serum concentration of MMP‐3 at all time‐points: 14.1 ng mL−1 [10.2–18.8] in 5A/5A; 19.6 ng mL−1 [15.0–24.4] in 5A/6A; and 24.0 ng mL−1 [20.1–32.3] in 6A/6A genotype at 3 months (P < 0.001 between all groups). Female patients had lower serum MMP‐3 concentration than male patients at all time‐points (14.8 ng mL−1 [9.4–20.8] vs. 19.9 ng mL−1 [16.0–26.9], P < 0.0001 at 3 months).Conclusions.  Serum concentration of MMP‐3 is significantly lower in the acute stage of MI than during recovery and is significantly influenced by −1612 5A/6A genotype and gender. Together with previous findings, these results primarily implicate MMP‐3 in atherosclerosis progression rather than in acute MI.
Long‐term beneficial effects of glipizide treatment on glucose tolerance in subjects with impaired glucose tolerance
Authors: ERIKSSON J. G. , LEHTOVIRTA M. , EHRNSTRÖM B. , SALMELA S. , GROOP L. 
Published: March 2006

Abstract.Aims.  To assess the efficacy and long‐term effects of glipizide treatment on glucose and insulin metabolism in individuals with impaired glucose tolerance (IGT).Methods.  Thirty‐seven first‐degree relatives of patients with type 2 diabetes fulfilling WHO criteria for IGT were randomized to treatment with either glipizide 2.5 mg once daily or matching placebo for 6 months. A 75 g, 2‐h oral (OGTT) and 60 min intravenous glucose tolerance test (IVGTT) were performed at baseline and after 6 months. The subjects were followed up for another 12 months after discontinuation of treatment and a repeat OGTT was performed at 18 months.Results.  Thirty‐three subjects fulfilled the study. Markers of insulin sensitivity – i.e. fasting insulin and HOMAIR‐index – improved in the glipizide group (P = 0.04 and 0.02 respectively) as well as HDL cholesterol (P = 0.05) compared with placebo group after 6 months. At 18 months, both fasting and 2 h glucose concentrations were significantly lower in the glipizide group compared with the placebo group (P = 0.04 and 0.03 respectively). The prevalence of type 2 diabetes was 29.4% in the placebo group and 5.9% in the glipizide group at 18 months. This equals an 80% relative risk reduction in the active treatment group.Conclusions.  Short‐term treatment with glipizide improves glucose and insulin metabolism in subjects with IGT primarily by improving insulin sensitivity mediated by lowering glucose toxicity, thereby providing the beta cells rest. Larger studies are needed to establish whether these effects are sufficient to prevent progression to manifest type 2 diabetes and associated cardiovascular morbidity in subjects at increased risk of developing type 2 diabetes.
A simple linear model for the effect of changes in metabolic risk factors on coronary heart disease
Authors: MOGELVANG R. , SCHARLING H. , JENSEN J. S. 
Published: March 2006

Abstract.Objectives.  The risk of having one or more metabolic risk factors in the development of coronary heart disease (CHD) is well estimated, but it still remains to be shown which influence any given change in the number of risk factors has on the overall risk of CHD.Design.  In this prospective cardiovascular population study, 10 194 participants were examined twice with a 5‐year interval for metabolic risk factors such as obesity, hypertension, hypercholesterolaemia and diabetes mellitus.Results.  During 14 years of follow‐up, 1724 incident cases of CHD were identified, 973 in men and 751 in women. The effect of an increase in the number of metabolic risk factors during a 5‐year interval on the relative risk of CHD could be determined to be statistically significant for both genders. But only for men, the effect of a decrease in the number of metabolic risk factors was statistically significant during the same time interval. Hence, by statistical analysis, a simple linear model could be constructed for men with two linear trend parameters, one corresponding to the number of metabolic risk factors at the first examination and one corresponding to the change in the number of metabolic risk factors from the first to the second examination. The parameters were 1.50 (1.39–1.63); P < 0.001 and 1.29 (1.18–1.41); P < 0.001, respectively.Conclusions.  This study suggests that it is possible to fit a simple linear model for the effect of changed number of metabolic risk factors on the risk of CHD.
Electrocardiographic and troponin T changes in acute ischaemic stroke
Authors: FURE B. , BRUUN WYLLER T. , THOMMESSEN B. 
Published: March 2006

Abstract.Background.  The mechanisms explaining morphological electrocardiogram (ECG) changes and increased troponin T (TnT) in acute stroke are unclear. The aims of the present study were to assess the prevalence of ECG and TnT changes in acute ischaemic stroke, to investigate whether ischaemic‐like ECG changes correlate to a rise in TnT and to examine whether ECG changes and elevated TnT predict a poor short‐time outcome.Methods.  From 2000 to 2002 a total of 279 patients suffering from acute ischaemic stroke were included prospectively in the present study. ECG was carried out at admission and on day 1 in all patients. TnT was analysed at admission and on day 1.Results.  The most frequent ECG changes were: prolonged QTc 36.0%, ST depression 24.5%, atrial fibrillation 19.9% and T wave inversion 17.8%. In logistic regression analyses, ST depression and Q waves were significantly associated with a rise in TnT. TnT was elevated (>0.04 μg L−1) in 26 patients (9.6%). In logistic regression analyses, a rise in TnT was significantly associated with a poor short‐term outcome (modified Rankin scale >3).Conclusion.  ECG changes are prevalent in acute ischaemic stroke. ST depression and Q waves are related to an increase in TnT, suggesting that these ECG changes may indicate coexisting ischaemic heart disease. A rise in TnT predicts a poor outcome. Patients with acute ischaemic stroke should be offered adequate treatment with secondary prevention and preferably a follow‐up with focus on cardiologic as well as neurological aspects.
Refractoriness to Short Day Lengths Augments Tonic and Gonadotrophin‐Releasing Hormone‐Stimulated Lutenising Hormone Secretion
Authors: Prendergast B. J. , Hotchkiss A. K. , Wen J. , Horton T. H. , Nelson R. J. 
Published: March 2006

AbstractSiberian hamsters (Phodopus sungorus) undergo reproductive involution following exposure to short winter day lengths. Following approximately 20 weeks of exposure to short day (SD) lengths, hamsters become refractory to the inhibitory effects of SD, and reproductive competence is restored in anticipation of spring. The extent to which changes in gonadal steroid‐dependent and ‐independent regulation of gonadotrophin secretion participate in this vernal reactivation of the gonads is not known. This experiment tested whether tonic and gonadotrophin‐releasing hormone (GnRH)‐stimulated regulation of lutenising hormone (LH) secretion differs between photoresponsive and photorefractory Siberian hamsters. Male hamsters born into long day (LD) lengths were castrated or subjected to a sham‐castration surgery at 17 days of age, implanted s.c. with blank or testosterone‐filled capsules, and housed in LD or SD thereafter. Baseline LH and LH responses to GnRH (200 ng/kg, s.c) were measured at 14 (photoresponsive) and 40 (photorefractory) weeks of age. Despite lower circulating testosterone concentrations in gonadally regressed SD hamsters on week 14, tonic LH concentrations were comparable among all groups of gonad‐intact hamsters on weeks 14 and 40; however, week 14 SD hamsters exhibited significantly higher GnRH‐stimulated LH responses. Tonic LH concentrations were indistinguishable among all groups of castrated hamsters bearing empty implants on week 14, but prolonged exposure to LD led to a decrease in resting LH, whereas prolonged exposure to SD resulted in an increase in LH. In castrated hamsters bearing testosterone implants, baseline LH concentrations were comparable in all groups, but GnRH treatment resulted in significantly higher LH concentrations in photorefractory (week 40, SD) hamsters relative to all other groups. The data suggest that the development of photorefractoriness in Siberian hamsters is characterised by enhanced gonadal hormone‐independent stimulation of LH secretion, and diminished sensitivity to inhibitory negative‐feedback effects of testosterone on LH secretion. Decreases in responsiveness of gonadotrophin secretion to gonadal hormone negative feedback may contribute to the process of photorefractoriness and assist in maintaining the growth of reproductive organs during the process of gonadal recrudescence.
When invaders meet locally adapted types: rapid moulding of hybrid zones between sculpins (Cottus, Pisces) in the Rhine system
Authors: NOLTE A. W. , FREYHOF J. , TAUTZ D. 
Published: March 2006

AbstractHybrid zones are commonly studied to dissect the processes that drive divergence among lineages, which have incomplete barriers of reproduction. Most hybrid zones have existed for an extended time making inferences on the initial mode of formation difficult. It is a priori unclear how fast a nascent hybrid zone would form as a response to endogenous and exogenous factors. We have studied several hybrid zones between two lineages of sculpins (Cottusspp.), which emerged due to a recent range expansion of one of the lineages along the river Rhine in the early 1990s. Applying a dense sampling across two contact areas and using a highly informative set of 45 microsatellite markers we found pronounced genetic structure. Steep genetic clines suggest that strong selective forces have shaped the respective hybrid zones from the beginning. We find that the zones are coupled to ecological transitions from small streams to larger rivers. The width of these zones is much smaller than estimates of annual individual dispersal distances, as estimated outside of the hybrid zones. The pattern is apparently not strongly affected by pre‐ or postzygotic reproductive isolation because numerous backcross hybrids occur within the zones. This suggests that strong natural selection acts against immigrant genotypes. The study exemplifies how local adaptation can play a key role in preventing admixture in dependence of the ecological context.
Natural hybrids in Atlantic eels (Anguilla anguilla,A. rostrata): evidence for successful reproduction and fluctuating abundance in space and time
Authors: ALBERT VICKY , JÓNSSON BJARNI , BERNATCHEZ LOUIS 
Published: March 2006

AbstractThe outcome of natural hybridization is highly variable and depends on the nonexclusive effects of both pre‐ and post‐mating reproductive barriers. The objective of this study was to address three specific questions regarding the dynamics of hybridization between the American and European eels (Anguilla rostrataandAnguilla anguilla). Using 373 AFLP loci, 1127 eels were genotyped, representing different life stages from both continents, as well as multiple Icelandic locations. We first evaluated the extent of hybridization and tested for the occurrence of hybrids beyond the first generation. Second, we tested whether hybrids were randomly distributed across continents and among Icelandic sampling sites. Third, we tested for a difference in the proportion of hybrids between glass eel and yellow eel stages in Iceland. Our results provided evidence for (i) an overall hybrid proportion of 15.5% in Iceland, with values ranging from 6.7% to 100% depending on life stages and locations; (ii) the existence of hybrids beyond the first generation; (iii) a nonrandom geographic distribution of hybrids in the North Atlantic; and (iv) a higher proportion of first and later generation hybrids in yellow eels compared to glass eels, as well as a significant latitudinal gradient in the proportion of hybrids in Icelandic freshwater. We propose that the combined effect of both differential survival of hybrids and variation in hybridization rate through time best explain these patterns. We discuss the possibility that climate change, which is impacting many environmental features in the North Atlantic, may have a determinant effect on the outcome of natural hybridization in Atlantic eels.
INVITED REVIEW: Life on the margin: genetic isolation and diversity loss in a peripheral marine ecosystem, the Baltic Sea
Authors: JOHANNESSON KERSTIN , ANDRÉ CARL 
Published: March 2006

AbstractMarginal populations are often isolated and under extreme selection pressures resulting in anomalous genetics. Consequently, ecosystems that are geographically and ecologically marginal might have a large share of genetically atypical populations, in need of particular concern in management of these ecosystems. To test this prediction, we analysed genetic data from 29 species inhabiting the low saline Baltic Sea, a geographically and ecologically marginal ecosystem. On average Baltic populations had lost genetic diversity compared to Atlantic populations: a pattern unrelated to dispersal capacity, generation time of species and taxonomic group of organism, but strongly related to type of genetic marker (mitochondrial DNA loci had lost c. 50% diversity, and nuclear loci 10%). Analyses of genetic isolation by geographic distance revealed clinal patterns of differentiation between Baltic and Atlantic regions. For a majority of species, clines were sigmoid with a sharp slope around the Baltic Sea entrance, indicating impeded gene flows between Baltic and Atlantic populations. Some species showed signs of allele frequencies being perturbed at the edge of their distribution inside the Baltic Sea. Despite the short geological history of the Baltic Sea (8000 years), populations inhabiting the Baltic have evolved substantially different from Atlantic populations, probably as a consequence of isolation and bottlenecks, as well as selection on adaptive traits. In addition, the Baltic Sea also acts a refuge for unique evolutionary lineages. This marginal ecosystem is thus vulnerable but also exceedingly valuable, housing unique genes, genotypes and populations that constitute an important genetic resource for management and conservation.
Recombinant cytochromes c biogenesis systems I and II and analysis of haem delivery pathways in Escherichia coli
Authors: Feissner Robert E. , Richard‐Fogal Cynthia L. , Frawley Elaine R. , Loughman Jennifer A. , Earley Keith W. , Kranz Robert G. 
Published: March 2006

SummaryGenetic analysis has indicated that the system II pathway for c‐type cytochrome biogenesis in Bordetella pertussis requires at least four biogenesis proteins (CcsB, CcsA, DsbD and CcsX). In this study, the eight genes (ccmA–H) associated with the system I pathway in Escherichia coli were deleted. Using B. pertussis cytochrome c4 as a reporter for cytochromes c assembly, it is demonstrated that a single fused ccsBA polypeptide can replace the function of the eight system I genes in E. coli. Thus, the CcsB and CcsA membrane complex of system II is likely to possess the haem delivery and periplasmic cytochrome c‐haem ligation functions. Using recombinant system II and system I, both under control of IPTG, we have begun to study the capabilities and characteristics of each system in the same organism (E. coli). The ferrochelatase inhibitor N‐methylprotoporphyrin was used to modulate haem levels in vivo and it is shown that system I can use endogenous haem at much lower levels than system II. Additionally, while system I encodes a covalently bound haem chaperone (holo‐CcmE), no covalent intermediate has been found in system II. It is shown that this allows system I to use holo‐CcmE as a haem reservoir, a capability system II does not possess.