bluuebunny/crossref_metadata_2025 huggingface dataset:
Variant proteins of Plasmodium vivax are not clonally expressed in natural infections
Authors: Fernandez‐Becerra Carmen , Pein Oliver , de Oliveira Tatiane Rodrigues , Yamamoto Marcio Massao , Cassola Antonio Carlos , Rocha Claudia , Soares Irene S. , de Bragança Pereira Carlos A. , del Portillo Hernando A.
Published: September 2005

Plasmodium vivax is the most widely distributed human malaria parasite and responsible for 70–80 million clinical cases each year and a large socio‐economical burden. The sequence of a chromosome end from P. vivax revealed the existence of a multigene superfamily, termed vir (P. vivax variant antigens), that can be subdivided into different subfamilies based on sequence similarity analysis and which represents close to 10–20% of the coding sequences of the parasite. Here we show that there is a vast repertoire of vir genes abundantly expressed in isolates obtained from human patients, that different vir gene subfamilies are transcribed in mature asexual blood stages by individual parasites, that VIR proteins are not clonally expressed and that there is no significant difference in the recognition of VIR‐tags by immune sera of first‐infected patients compared with sera of multiple‐infected patients. These data provide to our knowledge the first comprehensive study of vir genes and their encoding variant proteins in natural infections and thus constitute a baseline for future studies of this multigene superfamily. Moreover, whereas our data are consistent with a major role of vir genes in natural infections, they are inconsistent with a predominant role in the strict sense of antigenic variation.
LexA regulates the bidirectional hydrogenase in the cyanobacterium Synechocystis sp. PCC 6803 as a transcription activator
Authors: Gutekunst Kirstin , Phunpruch Saranya , Schwarz Christoph , Schuchardt Sven , Schulz‐Friedrich Rüdiger , Appel Jens
Published: September 2005

The bidirectional NiFe‐hydrogenase of Synechocystis sp. PCC 6803 is encoded by five genes (hoxEFUYH) which are transcribed as one unit. The transcription of the hox‐operon is regulated by a promoter situated upstream of hoxE. The transcription start point was located at −168 by 5′Race. Several promoter probe vectors carrying different promoter fragments revealed two regions to be essential for the promoter activity. One is situated in the untranslated 5′leader region and the other is found −569 to −690 nucleotides upstream of the ATG. The region further upstream was shown to bind a protein. Even though an imperfect NtcA binding site was identified, NtcA did not bind to this region. The protein binding to the DNA was purified and found to be LexA by MALDI‐TOF. The complete LexA and its DNA binding domain were overexpressed in Escherichia coli. Both were able to bind to two sites in the examined region in band‐shift‐assays. Accordingly, the hydrogenase activity of a LexA‐depleted mutant was reduced. This is the first report on LexA acting not as a repressor but as a transcriptional activator. Furthermore, LexA is the first transcription factor identified so far for the expression of bidirectional hydrogenases in cyanobacteria.
Hyphal differentiation in the exploring mycelium of Aspergillus niger
Authors: Vinck Arman , Terlou Maarten , Pestman Wiebe R. , Martens Edwin P. , Ram Arthur F. , van den Hondel Cees A. M. J. J. , Wösten Han A. B.
Published: September 2005

Mycelial fungi play a central role in element cycling in nature by degrading dead organic material such as wood. Fungal colonization of a substrate starts with the invasion of exploring hyphae. These hyphae secrete enzymes that convert the organic material into small molecules that can be taken up by the fungus to serve as nutrients. Using green fluorescent protein (GFP) as a reporter, we show for the first time that exploring hyphae of Aspergillus niger differentiate with respect to enzyme secretion; some strongly express the glucoamylase gene glaA, while others hardly express it at all. When a cytoplasmic GFP was used, 27% of the exploring hyphae of a 5‐day‐old colony belonged to the low expressing hyphae. By fusing GFP to glucoamylase and by introducing an ER retention signal, this number increased to 50%. This difference is due to cytoplasmic streaming of the reporter in the former case, as was shown by using a photo‐activatable GFP. Our findings indicate that a fungal mycelium is highly differentiated, especially when taking into account that hyphae in the exploration zone were exposed to the same nutritional conditions.
Structural analysis of a novel anionic polysaccharide from Porphyromonas gingivalis strain W50 related to Arg‐gingipain glycans
Authors: Paramonov Nikolay , Rangarajan Minnie , Hashim Ahmed , Gallagher Alex , Aduse‐Opoku Joseph , Slaney Jennifer M. , Hounsell Elizabeth , Curtis Michael A.
Published: September 2005

The Arg‐gingipains (RgpsA and B) of Porphyromonas gingivalis are a family of extracellular cysteine proteases and are important virulence determinants of this periodontal bacterium. A monoclonal antibody, MAb1B5, which recognizes an epitope on glycosylated monomeric RgpAs also cross‐reacts with a cell‐surface polysaccharide of P. gingivalis W50 suggesting that the maturation pathway of the Arg‐gingipains may be linked to the biosynthesis of a surface carbohydrate. We report the purification and structural characterization of the cross‐reacting anionic polysaccharide (APS), which is distinct from both the lipopolysaccharide and serotype capsule polysaccharide of P. gingivalis W50. The structure of APS was determined by 1D and 2D NMR spectroscopy and methylation analysis, which showed it to be a phosphorylated branched mannan. The backbone is built up of α‐1,6‐linked mannose residues and the side‐chains contain α‐1,2‐linked mannose oligosaccharides of different lengths (one to two sugar residues) attached to the backbone via 1,2‐linkage. One of the side‐chains in the repeating unit contains Manα1‐2Manα1‐phosphate linked via phosphorus to a backbone mannose at position 2. De‐O‐phosphorylation of APS abolished cross‐reactivity suggesting that Manα1‐2Manα1‐phosphate fragment forms part of the epitope recognized by MAb1B5. This phosphorylated branched mannan represents a novel polysaccharide that is immunologically related to the post‐translational additions of Arg‐gingipains.
Hairpin telomeres and genome plasticity in Borrelia: all mixed up in the end
Authors: Chaconas George
Published: September 2005

Spirochetes of the genus Borrelia have a highly unusual genome structure composed of over 20 replicons. Most of these replicons are linear and terminated by covalently closed hairpin ends or telomeres. Moreover, the linear replicons are affected by extensive DNA rearrangements, including telomere exchanges, DNA duplications, and harbour a large number of pseudogenes. The mechanism for the unusual genome plasticity in the linear replicons has remained elusive. The enzymatic machinery (the telomere resolvase ResT) responsible for generating the hairpin ends from replicative intermediates has recently been shown to also perform a reverse reaction that fuses telomeres on unrelated replicons. Infrequent stabilization of such fusion events over evolutionary time provides the first proposed biochemical mechanism for the DNA rearrangements that are so prominent in the linear replicons of B. burgdorferi.
LRP and H‐NS – cooperative partners for transcription regulation at Escherichia coli rRNA promoters
Authors: Pul Ümit , Wurm Reinhild , Lux Bianca , Meltzer Michael , Menzel Artur , Wagner Rolf
Published: September 2005

The synthesis of ribosomal RNAs in bacteria is tightly coupled to changes in the environment. This rapid adaptation is the result of several intertwined regulatory networks. The two proteins FIS and H‐NS have previously been described to act as antagonistic transcription factors for rRNA synthesis. Here we provide evidence for another player, the regulatory protein LRP, which binds with high specificity to all seven Escherichia coli rRNA P1 promoter upstream regions (UAS). Comparison of the binding properties of LRP and H‐NS, and characterization of the stabilities of the various complexes formed with the rRNA UAS regions revealed different binding modes. Binding studies with LRP and H‐NS in combination demonstrated that the two proteins interacted with obvious synergism. The efficiency of LRP binding to the rRNA regulatory region is modified by the presence of the effector amino acid leucine, as has been shown for several other operons regulated by this transcription factor. The effect of LRP on the binding of RNA polymerase to the rrnB P1 promoter and in vitro transcription experiments indicated that LRP acts as a transcriptional repressor, thus resembling the activity of H‐NS described previously. The results show for the first time that LRP binds to the regulatory region of bacterial rRNA promoters, and very likely contributes in combination with H‐NS to the control of rRNA synthesis. From the known properties of LRP a mechanism can be inferred that couples rRNA synthesis to changes in nutritional quality.
Role of BvgA phosphorylation and DNA binding affinity in control of Bvg‐mediated phenotypic phase transition in Bordetella pertussis
Authors: Jones Allison M. , Boucher Philip E. , Williams Corinne L. , Stibitz Scott , Cotter Peggy A.
Published: September 2005

To investigate the mechanism by which the Bordetella BvgAS phosphorelay controls expression of at least three distinct phenotypic phases, we isolated and characterized two B. pertussis mutants that were able to express Bvg– and Bvgi phase phenotypes but not Bvg+ phase phenotypes. In both cases, the mutant phenotype was due to a single nucleotide change in bvgA resulting in a single amino acid substitution in BvgA. In vitro phosphorylation assays showed that BvgA containing the T194M substitution was significantly impaired in its ability to use either BvgS or acetyl phosphate as a substrate for phosphorylation. Binding studies indicated that this mutant protein was able to bind an oligonucleotide containing a high‐affinity BvgA binding site in a manner similar to wild‐type BvgA, but was defective for binding the fhaB promoter in the absence of RNA polymerase (RNAP). By contrast, BvgA containing the R152H substitution had wild‐type phosphorylation properties but was severely defective in its ability to bind either the high‐affinity BvgA binding site‐containing oligonucleotide or the fhaB promoter by itself. Both mutant BvgA proteins were able to bind the fhaB promoter in the presence of RNAP however, demonstrating the profound effect that RNAP has on stabilizing the ternary complexes between promoter DNA, BvgA and RNAP. Our results are consistent with the hypothesis that BvgAS controls expression of multiple phenotypic phases by adjusting the intracellular concentration of BvgA∼P and they demonstrate the additive nature of BvgA binding site affinity and protein–protein interactions at different Bvg‐regulated promoters.
Serum leptin concentration in patients after heart transplantation
Authors: Żwirska‐Korczala Krystyna , Zakliczyński Michał , Berdowska Agnieszka , Zembala Marian , Kukla Michał
Published: September 2005

Abstract: Leptin is primarily produced by adipocytes but its receptors are expressed in a variety of tissues including the heart. Elevated plasma leptin levels predict acute myocardial infarction and it has been shown as acute phase reactant and a risk factor for coronary heart disease. The present study was undertaken to answer the question whether there exists a relationship or not, between serum leptin levels and grades of acute cellular rejection confirmed by elective endomyocardial biopsies in stable patients after orthotopic heart transplantation. We observed higher serum leptin levels compared with reference values, regardless of histopathologic biopsy findings studied. There was a positive correlation between serum leptin concentrations and body mass index, diastolic blood pressure, total cholesterol and low‐density lipoprotein. The elevated leptin levels found in heart transplant recipients could be due to the result of steroid therapy. These results point the need for further studies to explain the leptin role in heart transplant recipients.
Identification of cis‐regulatory elements involved in transcriptional regulation of the sea urchin SpFoxB gene
Authors: Fung Elizabeth‐Sharon , Thurm Carey , Reuille Rae , Brede Barbara , Livingston Brian T.
Published: September 2005

The SpFoxB gene is transiently expressed first in the mesoderm, then in the endoderm and oral ectoderm during sea urchin gastrulation. Perturbations of a number of proteins involved in endomesoderm specification have been shown to alter the mRNA levels of SpFoxB, but the cis‐regulatory elements required for expression of SpFoxB have not been examined. In order to investigate this, we have screened the SpFoxB gene for sequences that can drive its expression. Both positive and negative cis‐regulatory elements were found to be present. An enhancer was found that contains four GATA sites and four YY1 sites clustered within 210 base pairs (bp), as well as three lef/tcf binding sites. Electrophoretic mobility shifts indicate that the lef/tcf sites bind a complex of proteins that include β‐catenin in early cleavage, but not during subsequent stages of development. The GATA and YY1 sites bind nuclear proteins prior to SpFoxB transcription, and this binding diminishes coincident with cessation of transcription. Deletion of the GATA/YY1 sites causes a significant decrease in transcription. The DNA binding site of the SpFoxB protein has been determined, and Fox binding sites are found within the 5′ UTR of SpFoxB.
Repulsive guidance of axons of spinal sensory neurons in Xenopus laevis embryos: Roles of Contactin and notochord‐derived chondroitin sulfate proteoglycans
Authors: Fujita Naoko , Nagata Saburo
Published: September 2005

An immunoglobulin superfamily neuronal adhesion molecule, Contactin, has been implicated in axon guidance of spinal sensory neurons in Xenopus embryos. To identify the guidance signaling molecules that Contactin recognizes in tailbud embryos, an in situ binding assay was performed using recombinant Contactin‐alkaline phosphatase fusion protein (Contactin‐AP) as a probe. In the assay of whole‐mount or sectioned embryos, Contactin‐AP specifically bound to the notochord and its proximal regions. This binding was completely blocked by either digestion of embryo sections with chondroitinase ABC or pretreatment of Contactin‐AP with chondroitin sulfate A. When the spinal cord and the notochord explants were co‐cultured in collagen gel, growing Contactin‐positive spinal axons were repelled by notochord‐derived repulsive activity. This repulsive activity was abolished by the addition of either a monoclonal anti‐Contactin antibody, chondroitin sulfate A or chondroitinase ABC to the culture medium. An antibody that recognizes chondroitin sulfate A and C labeled immunohistochemically the notochord in embryo sections and the collagen gel matrix around the cultured notochord explant. Addition of chondroitinase ABC into the culture eliminated the immunoreactivity in the gel matrix. These results suggest that the notochord‐derived chondroitin sulfate proteoglycan acts as a repulsive signaling molecule that is recognized by Contactin on spinal sensory axons.
Abnormal gastroesophageal flap valve is highly associated with gastroesophageal reflux disease among subjects undergoing routine endoscopy in Taiwan
Authors: LIN BOR‐RU , WONG JAU‐MIN , CHANG MEI‐CHI , LIAO CHIEN‐CHUNG , YANG PEI‐MING , JENG JIIANG‐HUEI , LIAO WAN‐RU , WANG TEH‐HONG
Published: September 2005

Objective:  Gastroesophageal flap valve (GEFV) grade predicts severe gastroesophageal reflux disease in Caucasians, but its role in other populations is unclear. This study evaluated the significance of endoscopic grading of the GEFV in Taiwanese subjects.

Methods:  Five hundred and six consecutive patients undergoing routine check‐ups at the National Taiwan University Hospital were enrolled. Symptoms of upper gastrointestinal disease and endoscopic severity of esophageal mucosal injury were correlated to GEFV grades according to the Hill classification.

Results:  The frequency of abnormal valves (Hill grades III or IV) was 27.3%. Of these, 42.7% had erosive esophagitis (EE). The majority of patients with EE were classified as Los Angeles grades A and B (79.7 and 16.9%, respectively). The prevalence of EE, hiatal hernia and, to a lesser degree, non‐erosive reflux disease, increased with altered GEFV. Patients with abnormal valves were younger and more likely to be male, overweight, and to have atypical and extraesophageal symptoms.

Conclusions:  Taiwanese patients with abnormal GEFVs share similar characteristics and risk factors with the patients who have EE. Endoscopic grading of the GEFV is highly associated with GERD, and in particular EE, in subjects undergoing routine endoscopy.
The Interaction of Attraction and Selection: Implications for College Recruitment and Schneider's ASA Model
Authors: Slaughter Jerel E. , Stanton Jeffrey M. , Mohr David C. , Schoel William A.
Published: September 2005

Les jeunes qui viennent d’obtenir leur premier diplôme universitaire (≪college≫) constituent un potentiel important de candidats à l’embauche dans les grandes entreprises. Les responsables des organisations ont besoin de savoir en quoi les profils de ces futurs diplômés susceptibles d’être attirés et sélectionnés par l’organisation se différencient des profils de la population générale des candidats. Nous avons, dans cette recherche, étudié la relation existant entre les profils de 223 étudiants sur le point d’obtenir leur diplôme du ≪college≫ et l’attirance pour une organisation, l’obtention d’un score satisfaisant à une procédure de sélection et l’interaction de ces deux variables. Les résultats montrent que ceux qui sont attirés par l’organisation diffèrent de ceux qui ne le sont pas. Ceux qui seraient retenus pour la poursuite du recrutement sont différents de ceux qui seraient éliminés. Mais l’interaction de l’attirance et de la sélection n’est en rapport avec aucune des differences individuelles. En outre, l’attirance et la sélection n’interagissent pour réduire la variance sur aucune des variables de différences individuelles. Ces résultats ouvrent une nouvelle perspective sur les conséquences modélisées dans le schéma Attirance‐Sélection‐Elimination de B. Schneider (1987). On discute enfin des implications de notre recherche pour ce modèle et pour le recrutement des étudiants de ≪college≫.

New college graduates are an important source of hires in large firms. Of interest to organisational decision makers are how the individual‐difference profiles of soon‐to‐be college graduates that are likely to be attracted to, and selected by, the organisation compare with the profiles of the overall applicant population. In this research, we investigated how self‐reported attraction to an organisation, achievement of a passing score on an organisation's screening device, and the interaction of these two variables related to the individual‐difference profiles of 223 senior‐level college undergraduates. Results indicated that those who were attracted to the organisation differed from those who were not attracted. Those who would be screened in for further selection by the organisation differed from those who would be rejected. However, the interaction of attraction and screening was unrelated to any of the individual differences. Moreover, attraction and screening did not interact to restrict variance on any of the individual‐difference variables. These results provide a new perspective on the effects hypothesised in B. Schneider's (1987) Attraction‐Selection‐Attrition model. Implications for this model and for recruiting from the college student population are discussed.
Normative Controls and Self‐Reported Counterproductive Behaviors in the Workplace in China
Authors: Kwok Chi‐Ko , Au Wing Tung , Ho Jane M.C.
Published: September 2005

Les comportements contre‐productifs (CPB) sont des comportements déviants de salariés qui violent les normes et les valeurs de l’organisation et nuisent à la fois à l’entreprise et à son personnel. Il est montré, dans cet article, que des réactions négatives de la part de l’entourage professionnel peuvent avoir un effet de contrôle normatif et contrecarrer les CPB. On a posé l’hypothèse que le contrôle normatif formel perçu (c’est‐à‐dire les réactions de la hiérarchie envers les CPB) et le contrôle normatif informel perçu (c’est‐à‐dire les réactions des collègues envers les CPB) médiatisaient l’effet du nombre de personnes présentes au travail sur la fréquence d’apparition des CPB. 155 salariés ont répondu à un questionnaire d’auto‐évaluation. Les résultats confirmèrent que le contrôle normatif formel de la hiérarchie médiatisait significativement l’effet de la taille de l’équipe sur les CPB, mais aucun effet médiateur n’est apparu en ce qui concerne le contrôle normatif informel des collègues.

Counterproductive behaviors (CPBs) are employee deviant behaviors that violate the norms and values of organisations, and bring harm to both the company and its employees. This paper examined how negative reactions as a normative control from other employees may reduce CPB. It was hypothesised that perceived formal normative control (i.e. supervisor's reactions towards CPB) and perceived informal normative control (i.e. colleagues’ reactions towards CPB) mediated the effect of the number of staff at the workplace on the prevalence of CPB. One hundred and fifty‐five employees participated in this self‐report questionnaire study. Results showed that supervisor's formal normative control significantly mediated the effect of staff size at the workplace on CPB, but the mediating effect was not found for colleagues’ informal normative control.
Unidimensionality of Abbreviated Proactive Personality Scales across Cultures
Authors: Claes Rita , Beheydt Colin , Lemmens Björn
Published: September 2005

Vu la pertinence de la personnalité proactive et du comportement proactif pour l’efficacité des individus, des équipes et des organisations dans un environnement de plus en plus multiculturel, cette étude a examiné l’unidimensionnalité des formes abrégées de l’Echelle de Personnalité Proactive (PPS) de Bateman & Crant (1993) sur des données ni américaines, ni britanniques. L’unidimensionnalité des PPS à 10, 6, 5 et 4 items a été mise à l’épreuve grâce à une analyse factorielle et à une analyse de fidélité interne sur des échantillons indépendants provenant de trois pays: la Belgique (N= 822), la Finlande (N= 100) et l’Espagne (N= 100). Les résultats montrent que les versions de 4 et 5 items ne présentent aucune fidélité interne en Belgique, en Finlande et en Espagne, tandis que les deux autres formes abrégées sont satisfaisantes. L’analyse factorielle confirme qu’un modèle à facteur unique est une solution quasi optimale pour la PPS à 10 items. La PPS à 6 items mesure la personnalité proactive avec une fidélité interne cohérente à partir d’un facteur unique. Le score total sur l’échelle a été calculé par l’addition des scores sur les 6 items. On a obtenu sur un autre échantillon belge (N= 499) une corrélation des plus satisfaisantes (r= .92) entre la PPS de 6 items et la version originelle de 17 items.

Given the relevance of proactive personality and proactive behavior for effectiveness of individuals, teams, and organisations in an increasingly multicultural context, this study investigated the unidimensionality of abbreviated forms of the Proactive Personality Scale (PPS; Bateman & Crant, 1993) beyond American and British data. The unidimensionality of the 10‐item, the 6‐item, the 5‐item, and the 4‐item PPS was tested through internal reliability analysis and factor analysis across independent samples in three countries (Belgium, N= 822; Finland, N= 100; Spain, N= 100). The results showed that the 5‐item and the 4‐item versions were not internally reliable in Belgium, Finland, and Spain, while the two other abbreviated forms of the PPS were. Factor analysis showed that a one‐factor solution for the 10‐item PPS was a sub‐optimal solution. The 6‐item PPS, however, measured the proactive personality in an internally consistent manner and through a single factor. The total score on the scale was calculated by adding up scores on the six items. In a separate Belgian sample (N= 499), correlations of the 6‐item PPS with the original 17‐item PPS proved satisfactory with r= .92.
A Cross‐Cultural Study of the Work/Nonwork Interface among Israeli Nurses
Authors: Cohen Aaron , Kirchmeyer Catherine
Published: September 2005

Cette recherche analyse les effets différentiels des exigences du travail et du hors‐travail et de la gestion des rôles sur le conflit travail/hors‐travail, le projet de démission, la démission et l’absentéisme dans trois groupes ethniques. Des questionnaires ont été proposés à des infirmières juives (N= 102), musulmanes (N= 88) et chrétiennes (N= 50) dans trois hôpitaux israéliens. Des renseignements objectifs sur l’absentéisme et le turnover ont été obtenus auprès de l’administration de ces hôpitaux. Certaines liaisons parmi les variables de travail et de hors‐travail différaient selon le groupe ethnique. Par exemple, l’emploi à plein temps influençait le conflit travail/hors‐travail seulement chez les Juives et le contrôle hiérarchique avaient des effets opposés dans deux groupes. Davantage d’enfants entrainait plus de projets de démission chez les Arabes et moins chez les Juives. Plus de prise en charge personnelle provoquait moins de démissions réelles pour les Arabes et plus pour les Juives. Pour ce qui est du taux d’absentéisme, le contrôle hiérarchique et les pressions émanant du travail avaient des effets favorables chez les Arabes et des effects inverses mais plus faibles chez les Juives; le résultat est le méme en ce qui concerne le soutien organisationnel. Ces observations doivent rendre prudents les spécialistes des sciences‐humaines quand il s’agit d’extrapoler à d’autres situations culturelles les relations travail/hors‐travail découvertes dans une société.

This study examined the differential effects of both work and nonwork demands and inter‐role management on work/nonwork conflict, turnover intention, turnover, and absenteeism across three ethnic groups. Data from Jewish (N= 102), Muslim (N= 88), and Christian (N= 50) female nurses at three Israeli hospitals were collected by survey questionnaires. Objective data on absenteeism and turnover were collected from the hospitals’ records. Several relationships among the work and nonwork variables differed across the ethnic groups. For example, full‐time employment had an effect on work/nonwork conflict only for Jews and supervision had opposite effects across the two groups. More children meant more intention of turnover among Arabs and less among Jews. More personal coping meant lower actual turnover for Arabs and higher turnover for Jews. In the case of absence frequency, supervision and job tension had favorable effects for Arabs and smaller, adverse effects for Jews. Organisational support had a favorable effect for Arabs and a smaller, adverse effect for Jews. The findings serve to caution social scientists about generalising work and nonwork relationships identified in one society to other cultural settings.
Comparing Attribute Importance and Reason Methods for Understanding Behavior: An Application to Internet Job Searching
Authors: Westaby James D.
Published: September 2005

Pour tenter de comprendre le comportement de recherche d’emploi sur Internet, cette recherche compare les méthodes de l’importance attribuée et des causes motivationnelles. La méthode de l’importance attribuée évalue l’importance perçue de divers facteurs en jeu dans la décision d’utiliser Internet pour trouver un emploi. La méthode des causes motivationnelles évalue les facteurs spécifiques auxquels les gens font appel pour expliquer leur comportement à venir de recherche d’emploi sur Internet, ce qui implique une différenciation des raisons favorables ou non à l’adoption du comportement. A partir des données obtenues sur 224 demandeurs d’emploi ayant en moyenne 27.9 ans, une régression logislique montra que les variables d’importance attribuée expliquaient 5% de la variance du comportement objectivement mesuré de recherche d’emploi. Les variables de causes motivationnelles expliquaient 15% de la variance des comportements, ce qui représente un gain significatif en sus de ce que prédit la méthode de l’importance attribuée. De plus, la méthode des causes motivationnelles était en mesure d’identifier plusieurs antécédents du comportement de recherche d’emploi qui ěchappaient à la méthode de l’importance attribuée. Les résultats sont en faveur de l’exploitation des variables de causes motivationnelles par la recherche on psychologic appliquée.

This study compared attribute importance and reason methods for understanding internet job search behavior. The attribute importance method assessed the perceived importance of various factors involved in decisions to use the internet for job search. The reason method assessed the specific factors people use to explain their anticipated internet job search behavior, which included a differentiation of reasons for and reasons against performing the behavior. Logistic regression results from 224 job searchers (mean age 27.9 years) indicated that attribute importance variables explained 5 per cent of the variance in objectively measured job search behavior. Reason variables explained 15 per cent of the variance in behavior, which represents a significant increment in prediction over and above that explained by the attribute importance method. Moreover, the reason method was able to identify several determinants of job search behavior that were unidentified by the attribute importance method. Results provide strong support for using reason variables in applied psychological research.
Visual attention in deaf and hearing infants: the role of auditory cues
Authors: Harris Margaret , Chasin Joan
Published: September 2005

Background:  Successful communication with profoundly deaf children is heavily dependent on visual attention. Previous research has shown that mothers of deaf children – notably those who are deaf themselves – use a variety of strategies to gain their children's attention. This study compares patterns of visual attention in deaf and hearing children to determine how they are affected by the absence of auditory cues, especially when looking to the mother's face.

Method:  The visual attention of 18‐month‐old infants to their mothers was examined in two groups of deaf children (6 with deaf mothers and 6 with hearing mothers) and two of hearing children (6 with deaf mothers and 8 with hearing mothers). Dyads were observed in free play and 10 minutes of videorecorded interaction was analysed. All looks to the mother were classified as Spontaneous, Responsive (Child turns in response to something done by mother) or Elicited (Mother actively seeks to gain child's attention by, e.g., tapping or waving). The kind of event that attracted the child's attention in Responsive and Elicited episodes was also determined (e.g., object movement, speech, physical contact), as was the focus of the child's attention (e.g., mother's face, mother's body).

Results:  Responsive looks to the mother were the most frequent for all groups but on only about 25% of occasions were they directed to her face. Elicited and spontaneous looks occurred less often but were frequently directed to the mother's face. Spontaneous looking occurred in all groups but elicited looking very seldom occurred in Hearing–Hearing dyads. Overall, there were fewer looks to the mother in the two groups where mother and child had congruent hearing status, although the proportion of the looks to the mother's face was similar.

Conclusions:  Both spontaneous and elicited looks are likely to involve attention to the mother's face. However, while active elicitation of attention is an important part of successful communication with young deaf children, this does not appear necessary for typically developing hearing children who turn to look at their mother's face on hearing her voice. The implications of these findings for differences in the dynamics of communication with young deaf and hearing children are discussed.
Recognition of psychiatric disorders, and self‐perceived problems. A follow‐up study from age 8 to age 18
Authors: Sourander Andre , Haavisto Antti , Ronning John A. , Multimäki Petteri , Parkkola Kai , Santalahti Päivi , Nikolakaros Georgios , Helenius Hans , Moilanen Irma , Tamminen Tuula , Piha Jorma , Kumpulainen Kirsti , Almqvist Fredrik
Published: September 2005

Objective: To study the rate of, and factors associated with, recognition of psychiatric disorders and self‐perceived problems among 18‐year‐old adolescent boys.

Method: The study population consisted of 2347 Finnish boys born during 1981 attending military call‐up (79.7% of the original sample). At age 8, the boys were evaluated by parental and teacher Rutter scales and by self‐reports using the Child Depression Inventory (CDI). At military call‐up 10 years later, the boys filled in the Young Adult Self‐Report (YASR). Information about psychiatric disorders recognized at the military call‐up health examination was obtained from the national military register.

Results: About 4.6% of boys were recognized as having a psychiatric disorder at the military call‐up medical examination. In addition, 23.1% of boys reported emotional, behavioral or relational difficulties but were not recognized as having an ICD 10 psychiatric diagnosis at the military call‐up medical examination. A higher level of psychopathology, problems across different life domains and early onset of problems were more strongly associated with recognition of psychiatric disorder than with self‐reports of difficulties without a recognized psychiatric disorder. All informant sources, parents, teachers and children themselves at age 8, independently predicted recognition of psychiatric disorders and perceived difficulties 10 years later.

Conclusions: Only a minority of adolescents with psychiatric problems are recognized as having a psychiatric disorder in the health services. Efforts to prevent psychiatric disturbance in early life are emphasized. The use of screening methods in school health settings to detect children in need of child mental health services is justified.
Bivariate linkage scan for reading disability and attention‐deficit/hyperactivity disorder localizes pleiotropic loci
Authors: Gayán J. , Willcutt E.G. , Fisher S.E. , Francks C. , Cardon L.R. , Olson R.K. , Pennington B.F. , Smith S.D. , Monaco A.P. , DeFries J.C.
Published: September 2005

Background:  There is a growing interest in the study of the genetic origins of comorbidity, a direct consequence of the recent findings of genetic loci that are seemingly linked to more than one disorder. There are several potential causes for these shared regions of linkage, but one possibility is that these loci may harbor genes with manifold effects. The established genetic correlation between reading disability (RD) and attention‐deficit/hyperactivity disorder (ADHD) suggests that their comorbidity is due at least in part to genes that have an impact on several phenotypes, a phenomenon known as pleiotropy.

Methods:  We employ a bivariate linkage test for selected samples that could help identify these pleiotropic loci. This linkage method was employed to carry out the first bivariate genome‐wide analysis for RD and ADHD, in a selected sample of 182 sibling pairs.

Results:  We found evidence for a novel locus at chromosome 14q32 (multipoint LOD = 2.5; singlepoint LOD = 3.9) with a pleiotropic effect on RD and ADHD. Another locus at 13q32, which had been implicated in previous univariate scans of RD and ADHD, seems to have a pleiotropic effect on both disorders. 20q11 is also suggested as a pleiotropic locus. Other loci previously implicated in RD or ADHD did not exhibit bivariate linkage.

Conclusions:  Some loci are suggested as having pleiotropic effects on RD and ADHD, while others might have unique effects. These results highlight the utility of this bivariate linkage method to study pleiotropy.
Collaborative analysis of DRD4 and DAT genotypes in population‐defined ADHD subtypes
Authors: Todd Richard D. , Huang Hongyan , Smalley Susan L. , Nelson Stanley F. , Willcutt Erik G. , Pennington Bruce F. , Smith Shelley D. , Faraone Stephen V. , Neuman Rosalind J.
Published: September 2005

Background:  It has been proposed that some of the variability in reporting of associations between attention deficit hyperactivity disorder (ADHD) and candidate genes may result from mixing of genetically heterogeneous forms of ADHD using DSM‐IV criteria. The goal of the current study is to test whether population‐based ADHD subtypes defined by latent class analysis help resolve issues of variable findings across individual gene association studies.

Methods:  Three studies which had previously reported no associations between polymorphisms of the DRD4 and DAT genes and DSM‐IV defined ADHD were reanalyzed using population‐based and DSM‐IV defined ADHD subtypes.

Results:  Across studies no significant associations were found for either DRD4 or DAT polymorphisms using DSM‐IV ADHD subtypes. In contrast, a significant association was found between the combined data set for the 440 base pair 3′ DAT VNTR polymorphism and population‐defined severe combined ADHD (OR = 1.25, p = .01). A marginally significant association was also found between the 7 repeat DRD4 allele and population‐defined severe combined ADHD.

Conclusion:  Use of alternative population‐based defined ADHD subtypes may help resolve some of the variable results presented for candidate gene association studies in ADHD.
High sibling correlation on methylphenidate response but no association with DAT1‐10R homozygosity in Dutch sibpairs with ADHD
Authors: van der Meulen Emma M. , Bakker Steven C. , Pauls David L. , Oteman Nicole , Kruitwagen Cas L.J.J. , Pearson Peter L. , Sinke Richard J. , Buitelaar Jan K.
Published: September 2005

Background:  A minority of patients with attention‐deficit hyperactivity disorder (ADHD) do not respond favorably to methylphenidate. This has been partially associated with homozygosity for the Dopamine transporter (DAT1) 10‐repeat allele and the presence of one or two Dopamine D4 receptor (DRD4) 7‐repeat alleles. This study examined the sibling correlation of methylphenidate response rate and the possible association between response rate and these risk alleles.

Methods:  A sample of 82 Dutch children with ADHD, from 54 families, (including 30 singletons and 28 sib pairs), who used methylphenidate, was phenotyped according to DSM‐IV criteria. Patients were members of affected sib pairs and were genotyped for DAT1 and DRD4. The sibling Intraclass Correlation Coefficient for methylphenidate response rate was calculated. The association between individual response rates and the risk alleles was examined using linear regression techniques.

Results:  The Intraclass Correlation Coefficient was significant (r = .563, p = .001). No evidence was found establishing an association between methylphenidate response and DAT1‐homozygosity. There was a positive trend towards association with the presence of one or two DRD4‐7R alleles.

Conclusions:  The sibling correlation may indicate a familial clustering of methylphenidate response. This response is possibly associated with the presence of one or two alleles at the DRD4‐7R locus, but not with DAT1‐10R homozygosity in the Dutch population.
Introductory guide to the language of molecular genetics
Authors: Eley Thalia C. , Craig Ian W.
Published: September 2005

Background: This special section on molecular genetics was invited in order to raise awareness of the potential of molecular genetic approaches to inform child psychologists, psychiatrists and related professionals. As much of the terminology is specific to the field, this introductory guide aims to aid readers who may be unfamiliar with the approaches of this discipline.

Methods: Basic terminology and genetic processes are described, with sections covering ‘The Human Genome’ and ‘Genetic Markers’.

Results: The range of genetic markers is growing all the time, but those that are thought to be functional and/or are highly variable are particularly useful.

Conclusions: Genotyping approaches that offer high efficiency, thus allowing for large numbers of genotypes on large numbers of individuals, are likely to come to the fore in the next few years.
Introductory guide to the statistics of molecular genetics
Authors: Eley Thalia C. , Rijsdijk Frühling
Published: September 2005

Background:  This introductory guide presents the main two analytical approaches used by molecular geneticists: linkage and association.

Methods:  Traditional linkage and association methods are described, along with more recent advances in methodologies such as those using a variance components approach.

Results:  New methods are being developed all the time but the core principles of linkage and association remain the same. The basis of linkage is the transmission of a marker along with a disease within families, whereas association is based on the comparison of marker frequencies in case and control groups.

Conclusions:  It is becoming increasingly clear that effect sizes of individual markers on diseases and traits are likely to be very small. As such, much greater power is needed, and correspondingly greater sample sizes. Although non‐replication is still a problem, molecular genetic studies in some areas such as attention deficit/hyperactivity disorder (ADHD) are starting to show greater convergence. Epidemiologists and other researchers with large well‐characterized samples will be well placed to use these methods. Inter‐disciplinary studies can then ask far more interesting questions such as those relating to developmental, multivariate and gene–environment interaction hypotheses.
Colour perception in ADHD
Authors: Banaschewski Tobias , Ruppert Sinje , Tannock Rosemary , Albrecht Björn , Becker Andreas , Uebel Henrik , Sergeant Joseph A. , Rothenberger Aribert
Published: September 2005

Attention‐deficit/hyperactivity disorder (ADHD) is associated with unexplained impairments on speeded naming of coloured stimuli. These deficits may reflect hypofunctioning retinal dopaminergic mechanisms impairing particularly blue–yellow colour discrimination. Colour perception and rapid colour naming ability were investigated in 14 children with ADHD and 13 healthy peers matched for age, gender, and IQ, using the Farnsworth–Munsell 100 Hue Test (FMT) and the Stroop‐Colour‐Word test. Children with ADHD committed more errors on the FMT, particularly on discrimination of colours along the blue–yellow axis, and were slower on Stroop subtests involving colour naming. However, the latter deficit was accounted for similarly by blue–yellow and red–green discrimination abilities. Blue–yellow colour perception problems in ADHD contribute to but do not fully explain the observed slowed colour naming.
In vitro fertilisation in Sweden: obstetric characteristics, maternal morbidity and mortality
Authors: Källén Bengt , Finnström Orvar , Nygren K.G. , Otterblad Olausson Petra , Wennerholm Ulla‐Britt
Published: September 2005

Objective  To investigate obstetric characteristics, maternal morbidity and mortality among Swedish women giving birth after in vitro fertilisation (IVF) treatment.

Design  Register study.

Setting  Nationwide study in Sweden.

Sample  All women known to have had IVF in Sweden 1982–2001.

Methods  Using Swedish health registers, women who had given birth after IVF were identified from all Swedish IVF clinics and compared with all women who gave birth. Analysis was performed with the Mantel–Haenszel technique.

Main outcome measures  Diagnoses during pregnancy, at delivery and at re‐admission within 60 days after delivery and risk of cancer.

Results  IVF women had an increased risk of bleeding in early pregnancy [odds ratio (OR) = 4.59, 95% confidence interval (95% CI) 4.08–5.15] and of ovarian torsion during pregnancy (OR = 10.6, 5.69–10.7). They were also more likely to encounter pre‐eclampsia (OR = 1.63, 1.53–1.74), placental abruption (2.17, 1.74–2.72), placenta praevia (3.65, 3.15–4.23), bleeding in association with vaginal delivery (1.40, 1.38–1.50) and premature rupture of membranes (PROM) (2.54, 2.34–2.76). Interventions including caesarean sections (1.38, 1.32–1.43) and induction of labour (1.37, 1.29–1.46) in singleton pregnancies was more frequent. The type of IVF method had little effect on these results, but there was a tendency for women who had received intra‐cytoplasmatic sperm injection (ICSI) to have slightly fewer complications than women having standard IVF. There was a significant decrease in cancer risk after IVF (0.79, 0.69–0.91) but a suggested increase in the risk of ovarian cancer both before (2.70, 1.49–4.91) and after (2.08, 1.15–3.76) IVF. No change in mortality was observed.

Conclusions  Women treated with IVF had an increased obstetric morbidity. This seems to contribute little to the well‐known increased risk of preterm delivery.
The outcomes of pregnancy among imprisoned women: a systematic review
Authors: Knight Marian , Plugge Emma
Published: September 2005

Objective  To investigate the association between maternal imprisonment during pregnancy and perinatal outcomes.

Design  Systematic review and meta‐analysis.

Setting  Prisons in developed countries.

Population  Imprisoned pregnant women.

Methods  Two reviewers extracted the data independently according to a fixed protocol. Studies were included if they were cohort or case–control studies with women identified as being imprisoned at any point during pregnancy and if they included a comparison group of women who had not been imprisoned. Case series without a comparison group of women who were not imprisoned were excluded, as were studies that did not include information on the pre‐specified outcomes.

Main outcome measures  Perinatal or infant death, stillbirth, preterm delivery, low birthweight, fetal anomalies and use of breast milk substitutes.

Results  Of 28 relevant papers, 10 met the inclusion criteria, involving 1960 imprisoned pregnant women and 10,858 controls. There were significant differences in results between studies comparing imprisoned women with population controls and those making comparisons with disadvantaged control women. Imprisoned women are more likely to deliver prematurely and have a low birthweight baby than population control women. However, when compared with a similarly disadvantaged group, imprisoned woman are less likely to have a stillbirth or low birthweight baby, suggesting imprisonment may have a beneficial effect.

Conclusions  Particular perinatal outcomes appear to be improved in imprisoned women compared with similarly disadvantaged women. Imprisonment of the mother has a beneficial effect on the birthweight of her baby.