bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three measures of closeness in adolescents’ relationships with parents and friends: Variations and developmental significance
Authors: Repinski Daniel J. , Zook Joan M. 
Published: January 2005

AbstractTwo studies examined the nature and developmental significance of closeness in adolescents’ relationships with parents and friends. Three measures of relationship closeness (i.e., interdependence, emotional tone, and subjective opinion) were compared and contrasted. In Study 1, grade and gender differences in closeness in relationships with mothers, fathers, and friends were examined. Participants were 133 adolescents in Grades 7, 9, and 11 and 135 of their parents. Closeness in relationships with mothers, fathers, and friends varied based on closeness measure, grade of adolescent, gender of adolescent, and gender of parent. The results suggest that the interdependence measure offers a perspective on adolescents’ close relationships that differs from that provided by the emotional tone and subjective opinion measures. In Study 2, associations were examined between the three measures of closeness in adolescents’ relationships with mothers, fathers, and friends and adolescents’ problem behavior, substance use, and school performance. Participants included 107 adolescents in Grades 7 and 10. In combination, the measures of closeness in relationships with mothers and with fathers explained significant variability in the criterion variables, and reports of interdependence and emotional tone emerged as unique, significant predictors. The results highlight distinctions among the three conceptualizations that are commonly purported to assess a close relationship and point to the utility and validity of interdependence and emotional tone as measures of closeness in adolescents’ relationships.
Endothelin‐1‐induced proliferation of human endothelial cells depends on activation of K+ channels and Ca2+ influx
Authors: Kuhlmann C. R. W. , Most A. K. , Li F. , Münz B. M. , Schaefer C. A. , Walther S. , Raedle‐Hurst T. , Waldecker B. , Piper H. M. , Tillmanns H. , Wiecha J. 
Published: January 2005

AbstractAims:  Endothelin‐1 (ET‐1) promotes endothelial cell growth. Endothelial cell proliferation involves the activation of Ca2+‐activated K+ channels. In this study, we investigated whether Ca2+‐activated K+ channels with big conductance (BKCa) contribute to endothelial cell proliferation induced by ET‐1.Methods:  The patch‐clamp technique was used to analyse BKCa activity in endothelial cells derived from human umbilical cord veins (HUVEC). Endothelial proliferation was examined using cell counts and measuring [3H]‐thymidine incorporation. Changes of intracellular Ca2+ levels were examined using fura‐2 fluorescence imaging.Results:  Characteristic BKCa were identified in cultured HUVEC. Continuous perfusion of HUVEC with 10 nmol L−1 ET‐1 caused a significant increase of BKCa open‐state probability (n = 14; P < 0.05; cell‐attached patches). The ETB‐receptor antagonist (BQ‐788, 1 μmol L−1) blocked this effect. Stimulation with Et‐1 (10 nmol L−1) significantly increased cell growth by 69% (n = 12; P < 0.05). In contrast, the combination of ET‐1 (10 nmol L−1) and the highly specific BKCa blocker iberiotoxin (IBX; 100 nmol L−1) did not cause a significant increase in endothelial cell growth. Ca2+ dependency of ET‐1‐induced proliferation was tested using the intracellular Ca2+‐chelator BAPTA (10 μmol L−1). BAPTA abolished ET‐1 induced proliferation (n = 12; P < 0.01). In addition, ET‐1‐induced HUVEC growth was significantly reduced, if cells were kept in a Ca2+‐reduced solution (0.3 mmol L−1), or by the application of 2 aminoethoxdiphenyl borate (100 μmol L−1) which blocks hyperpolarization‐induced Ca2+ entry (n = 12; P < 0.05).Conclusion:  Activation of BKCa by ET‐1 requires ETB‐receptor activation and induces a capacitative Ca2+ influx which plays an important role in ET‐1‐mediated endothelial cell proliferation.
Polyethylene glycol but not mifepristone prevents intestinal lymphocyte loss following treadmill exercise in mice
Authors: Quadrilatero J. , Guan J. , Boudreau J. , Marra S. , Hoffman‐Goetz L. 
Published: January 2005

AbstractCirculating lymphocyte numbers decrease following intense physical activity, possibly due to exercise‐induced apoptosis. Increased reactive oxygen species (ROS) and glucocorticoids (GC) following exercise contribute to lymphocyte apoptosis. Intestinal lymphocyte (IL) numbers also decrease following exercise.Aim:  The purpose of this study was to determine the contribution of GC to exercise‐induced IL loss.Methods:  Female C57BL/6 mice (n = 178) were randomized to five drug conditions: (1) single injection of the glucocorticoid receptor antagonist mifepristone (MIF) solubilized in polyethylene glycol (PEG); (2) three injections of MIF (repeated MIF) PEG; (3) single injection of PEG (PEG); (4) three injections of PEG (repeated PEG); or (5) repeated injections of saline (SAL). Within each drug group mice were further randomized to exercise conditions: (1) control condition (non‐exercised); (2) treadmill running with sacrifice immediately following the exercise; or (3) treadmill running with sacrifice 24 h after completion of the exercise.Results:  There was a significant exercise effect, across all T lymphocyte subsets, in SAL (P < 0.01), PEG (P < 0.01) and MIF (P < 0.01) treated mice but not in mice given repeated PEG or repeated MIF exposure. The exercise effect was due to reduced IL numbers 24 h post‐exercise compared with non‐exercised controls.Conclusion:  These results suggest that GC are not directly responsible for IL cell loss following exercise. Repeated exposure to PEG may confer protection in the gastrointestinal tract from exercise‐induced lymphocyte depletion. Because PEG inhibits ROS generation in experimental cell injury, the mechanisms for IL loss after exercise may involve oxidative stress.
Regional intestinal adaptations in Na+,K+‐ATPase in experimental colitis and the contrasting effects of interferon‐γ
Authors: Magro F. , Fraga S. , Ribeiro T. , Soares‐da‐Silva P. 
Published: January 2005

AbstractAims:  This study evaluated Na+,K+‐ATPase activity and the abundance of α1 subunit Na+,K+‐ATPase in experimental colitis and gathered evidence on the effects of interferon‐γ (IFN‐γ) on intestinal Na+,K+‐ATPase.Methods:  Colitis was induced by the intrarectal administration of 2,4,6‐trinitrobenzene sulphonic acid (TNBS, 30 mg/250 μL). Na+,K+‐ATPase activity was determined as the difference between total and ouabain‐insensitive ATPase. The abundance of Na+,K+‐ATPase was analysed by immunoblotting.Results:  Na+,K+‐ATPase activity was markedly reduced in the proximal colonic mucosa of TNBS‐treated rats, whereas upstream in the terminal ileal mucosa a marked increase in sodium pump activity was observed. At the jejunal level no significant changes in Na+,K+‐ATPase activity were observed between TNBS‐treated rats and corresponding controls (ethanol‐treated rats). No changes were observed in the abundance of α1 subunit Na+,K+‐ATPase in the proximal colon, terminal ileum and jejunum. The administration of IFN‐γ (50 000 U) 48 h before sacrifice reduced both Na+,K+‐ATPase activity and the abundance of α1 subunit Na+,K+‐ATPase in the proximal colon. Dexamethasone prevented colonic inflammation and decreases in proximal colonic Na+,K+‐ATPase activity in TNBS‐treated rats, but did not affect the INF‐γ‐induced decrease in colonic Na+,K+‐ATPase activity.Conclusions:  The increase in ileal Na+,K+‐ATPase activity upstream to the lesioned colonic mucosa, where Na+,K+‐ATPase activity was markedly reduced, might indicate a compensatory process to counteract the decrease in water and electrolyte absorption at the colonic level. This decrease in colonic Na+,K+‐ATPase activity is likely not related to INF‐γ‐induced downregulation of Na+,K+‐ATPase.
The Neurobiology of Social Bonds
Authors: Kendrick Keith M. 
Published: January 2005

SummaryWhen released in the brain through giving birth or mating, the neuropeptides oxytocin and vasopressin are involved in promoting parent–offspring and monogamous bonds in animals such as sheep and voles. Bonds are only formed in species where receptors for these neuropeptides are highly expressed in dopamine‐producing reward centres. In humans, dysfunctions in these same systems can be associated with autism and, when we see people we love, these systems become activated
Potential benefit from using the αs1‐casein genotype information in a selection scheme for dairy goats
Authors: Sánchez A. , Ilahi H. , Manfredi E. , Serradilla J. M. 
Published: January 2005

SummaryA stochastic approach is proposed to predict responses to selection when using αs1‐casein genotype information in a selection scheme of a Spanish breed of dairy goats. Two independent selection objectives were considered: protein yield (PY), where the major additive gene CSN1S1, which codes for αs1‐casein, has a small effect, and protein content (P%), where this gene has a large effect on performances. Significant differences in response between using and ignoring information on the major gene were observed only when the major gene has a large effect. The main result was in the case of P%, the total genetic gain obtained in the early generations of selection was maintained in the long‐term. Taking account of genotype information either in the evaluation model or in the selection criteria leads to a faster fixation of the favourable allele and a reduction of the total genetic variance over generations. The inbreeding rates varied across generations, the highest rates observed in later generations of selection and when the major gene has a large effect and its genotype was included in the genetic evaluation procedure. It is concluded that inclusion of the casein genotype as an additional selection criteria will improve gains for protein traits, in particular P%. Recommendations are also given in order to optimize the use of this molecular information in dairy goat selection programs.
A simulation study on the detection of causal mutations from F2 experiments
Authors: Varona L. , Gómez‐Raya L. , Rauw W.M. , Noguera J.L. 
Published: January 2005

SummaryA simulation study has been performed to evaluate the power and the rate of false positives for the detection of causal mutations under two different models of analysis. We used an F2 design generated from an F0 population of five sires of line 1 and 40 dams of line 2 to produce an F1 population of 10 sires and 80 dams. Two different locations of the causal mutation and several frequencies of the mutations in the parental populations were considered. The first model included only the genetic configuration of the mutation, while the second model also included the probability of line origin given the neutral markers. Both models performed well when the mutation at the candidate gene was the causal mutation, although a greater power was obtained using the first model, because of its relative simplicity compared to the second one. However, when the candidate gene mutation was a neutral mutation, the second model presented a lower rate of false positives than the first. Moreover, in some cases the second model allowed distinction between the neutral and the causal mutation. The F2 design has a great power to detect quantitative trait loci provided by linkage disequilibrium, but also makes it difficult to discriminate between causal and neutral mutations. Therefore a high percentage of false positives can be expected. The limitations of F2 designs for discriminating between neutral and causal mutations are discussed.
An improved protocol for the production of AFLPTM markers in complex genomes by means of capillary electrophoresis
Authors: Papa R. , Troggio M. , Ajmone‐Marsan P. , Nonnis Marzano F. 
Published: January 2005

SummaryThe amplified fragment‐length polymorphism (AFLP) technology is a recently introduced method to investigate genomes of different complexity, from microbial to higher organisms. It is applied to purposes as diverse as identification of species, strain and varieties, investigation of genetic diversity within and between populations, simple and complex trait mapping, and construction of linkage and physical maps. This technology has been designed on the use of primers labelled with radioactivity and on AFLP fragment separation on sequencing gel. We show that the original EcoRI/TaqI AFLP protocol does not perform appropriately when transferred to fluorescent labelling and capillary electrophoresis (CE), and propose an improved protocol for the production of high‐quality AFLP markers in fish, rodents and artiodactyles by means of the Beckman‐Coulter CEQ2000 automatic DNA sequencer. In addition, we describe the procedure routinely used in our laboratory to obtain binary matrices from AFLP profiles with the aid of Genographer free‐share software (vers. 1.6.0, J.J. Benham, Montana State University), able to elaborate original fragment data and convert them to standard graphical formats for phylogenetic analyses. Comparison with radioactive AFLPs in goats confirmed the reliability of the protocol developed for CE. In fact, 107 fragments generated by two primer combinations and identified by both techniques were attributed the same scoring. Compared with traditional methods, the use of capillary systems and automated analysis increases data throughput and scoring reliability, decreasing the overall experimental error.
The value of prior information for detection of QTL affecting longitudinal traits: an example using Von Bertalanffy growth function
Authors: Varona L. , Gómez‐Raya L. , Rauw W.M. , Ovilo C. , Clop A. , Noguera J.L. 
Published: January 2005

SummaryA Bayesian procedure is presented for detecting quantitative trait loci (QTL) affecting longitudinal traits. The statistical model assumes a QTL affecting the prior distribution of the parameters of a given production function, under a hierarchical Bayesian scheme. Marginal posterior distributions for the effects associated with the QTL are calculated using Markov chain Monte Carlo methods. Furthermore, the Bayesian analysis allows the use of some available relevant information that can improve the detection of the QTL substantially. To illustrate the procedure, an example of QTL detection using the Von Bertalanffy growth function is presented with a F2pig population bred from Iberian boars and Landrace sows. Animals of the F2population were genotyped for seven markers in chromosome 2 (SSC2). Two prior distributions for the mean effect of the parameters related with birth and adult weight were compared. On the one hand, vague prior distributions were used, and, on the other, there were assumed univariate Gaussian distributions that ensure biologically meaningful adult and birth weights on the posterior growth curves. Results from the second prior distribution supported the presence of QTL, by showing that individuals with both alleles of Iberian origin had lower rates of maturation. On the contrary, when vague priors were used, the procedure was not able to detect QTL.
Major histocompatibility complex locus DRA polymorphism in the endangered Sorraia horse and related breeds
Authors: Luís C. , Cothran E.G. , Oom M.M. , Bailey E. 
Published: January 2005

SummaryThe major histocompatibility complex (MHC) genes play well‐defined roles in eliciting immune responses and combating infectious diseases. This genetic system is among the most polymorphic. The extent of genetic variation within a population has been directly correlated with fitness for many traits. The MHC class II locus DRA polymorphism was analysed in the endangered Sorraia horse, two other Portuguese and four New World horse breeds considered to be historically close to the Sorraia. Comparison of the Sorraia with other breeds demonstrated less MHC variation among Sorraia horses. If DRA polymorphism provides greater disease resistance, selective breeding to increase MHC polymorphism may increase fitness of this population.
Fine mapping of a QTL for intramuscular fat on porcine chromosome 6 using combined linkage and linkage disequilibrium mapping
Authors: Uleberg E. , Widerøe I.S. , Grindflek E. , Szyda J. , Lien S. , Meuwissen T.H.E. 
Published: January 2005

SummaryIn this study data from a commercial Norwegian slaughter pig cross was analysed to confirm a previous reported quantitative trait locus (QTL) affecting intramuscular fat (IMF) on porcine chromosome 6. The data consisted of an old experiment, in which the QTL was previously detected, and new experimental data from the Norwegian slaughter pig cross. The old and new experimental data were analysed separately and together. A previously described method combining linkage and linkage disequilibrium analysis (LDLA) was used for the analysis, but this method assumes that all animals are descendants from a common base population, which is not realistic in a cross between different breeds. An adjusted version of the method, able to distinguish between different breeds in the cross, is presented here. Using the LDLA method, we were not able to confirm the QTL in the old experimental data, because the genetic variance could be explained by the polygenic effect. Analysis from the new experimental data did however detect the QTL, and analysing the data from both experiments together gave highly significant results for a QTL (p < 0.001) between markers SW1355 and SW1823. The main conclusion is therefore that the previously reported QTL for IMF on porcine chromosome 6 was confirmed within a 8.7‐cM confidence interval.
Frequency distribution of a Cys430Ser polymorphism in peroxisome proliferator‐activated receptor‐gamma coactivator‐1 (PPARGC1) gene sequence in Chinese and Western pig breeds
Authors: Kunej T. , Wu X.‐L. , Berlic T.M. , Michal J.J. , Jiang Z. , Dovc P. 
Published: January 2005

SummaryIdentification of major genes, that genetically impact fat tissue formation is important for successful selection of lean animals with good meat quality. Because of its central role in fat cell differentiation and muscle fibre type determination, PPARGC1 is a potential candidate gene affecting fattening traits and pig meat quality. In this study, a T/A substitution at position 1378 (GenBank accession no. AY346131) in the porcine PPARGC1 gene causing a Cys430Ser amino acid substitution at position 430 was genotyped on a total of 239 animals, including 101 from seven Chinese and 138 from six Western pig breeds. Bayesian analysis revealed that the mean frequency of allele T (Cys) was 92.64 ± 4.82% in Chinese pigs, and 45.99 ± 4.13% in Western pigs. The 95% interval of the posterior mean frequency of allele T was 0.82–1.00 in Chinese pigs and 0.38–0.54 in Western pigs, indicating these two groups of pigs diverged at this locus during genetic evolution of the breed. Because marked differences in fat and lean tissue deposition exist between Western and Chinese pig breeds, this Cys430Ser exchange in the PPARGC1 gene deserves further evaluation to determine its phenotypic effect on fattening and carcass traits in commercial pig populations.
Navigating the Transition to Junior High School: The Influence of Pre‐Transition Friendship and Self‐System Characteristics
Authors: Aikins Julie Wargo , Bierman Karen L. , Parker Jeffrey G. 
Published: January 2005

Abstract The present study examined the influence of pre‐transition friendship and self‐system characteristics on junior high school transition adjustment in a sample of 111 early adolescent girls and boys. Transition adjustment was defined in terms of youth's post‐transition friendship quality, emotional distress, and school adjustment. Pre‐transition friendship characteristics were directly linked with both post‐transition friendship quality and school adjustment, while youth's expected possible selves, a component of youth's self‐system, made additional unique contributions to the prediction of youth's emotional distress and school adjustment. Results suggest the importance of developmentally salient friendship and self‐system characteristics in contributing to individual variability in transition adaptation.
The Implications of Having High‐achieving Versus Low‐achieving Friends: A Longitudinal Analysis
Authors: Altermatt Ellen Rydell , Pomerantz Eva M. 
Published: January 2005

Abstract The present research examines the achievement‐related implications of establishing friendships with high‐achieving versus low‐achieving classmates. Fifth‐ , sixth‐ , and seventh‐grade students (N=929) participated. During the fall and spring semesters, the report card grades of children and their friends were obtained and children completed questionnaire measures of their self‐evaluative beliefs and preference for challenge. Results suggest that for low‐achieving students there are tradeoffs associated with establishing and maintaining friendships with high‐achieving classmates. Specifically, low achievers who established and maintained friendships with high‐achieving friends evaluated themselves less positively, but also performed better academically, than low achievers with similarly low‐achieving friends. Fewer tradeoffs emerged for high achievers.
Patterns of Affiliation with Delinquent Friends During Late Childhood and Early Adolescence: Correlates and Consequences
Authors: Vitaro Frank , Brendgen Mara , Wanner Brigitte 
Published: January 2005

Abstract This study examined longitudinal patterns of affiliation with delinquent friends during late childhood and early adolescence, i.e., from ages 10 through 13, in a sample of 376 participants of both genders. Four groups with distinct affiliation profiles were found: an early affiliative group, a late affiliative group, a declining group (i.e., a group that affiliates with delinquent friends early on but much less so thereafter), and a group of children who did not affiliate with delinquent friends throughout the period covered in this study. There was also a fifth group of children who had no mutual friends throughout. The proportion of boys and girls varied in some groups but not in others. Participants’ own delinquency and depression trajectories as well as other behavior‐ , peer‐ , school‐ , and family‐related correlates were examined in association with group membership through the use of growth curves analysis. The results are discussed in light of prevalent theories about the role of delinquent friends with respect to externalizing and internalizing problems.
A Contextual Approach to the Development of Self‐regulatory Competencies: The Role of Maternal Unresponsivity and Toddlers’ Negative Affect in Stressful Situations
Authors: Rodriguez Monica L. , Ayduk Ozlem , Aber J. Lawrence , Mischel Walter , Sethi Anita , Shoda Yuichi 
Published: January 2005

Abstract A prospective study examined the effects of maternal unresponsivity and of toddlers’ own negative affect on the child's subsequent ability to use effective attentional control strategies in preschool. Maternal and child behaviors were measured in situations that varied in the level of stress to test the hypothesis that behaviors in high stress situations would be more diagnostic of children's subsequent self‐regulatory behavior. As predicted, both maternal unresponsivity and toddlers’ negative affect, particularly in a high stress as opposed to a low stress situation, predicted children's later use of ineffective attentional control strategies. Similarly, maternal disengagement that occurred contingent to toddlers’ distress predicted ineffective attentional control strategies whereas maternal disengagement in response to toddlers’ non‐distress behaviors did not. The findings supported the utility of a contextual approach to understanding the impact of maternal and child characteristics on the development of self‐regulatory skills.