bluuebunny/crossref_metadata_2025 huggingface dataset:
Every child should have one: what it means to be a learning guide
Authors: Bullock Kate , Wikeley Felicity
Published: February 2008

This article discusses the relationship between the newly identified learning guide and personal learning. It draws on recent research that has critically examined the role of the personal tutor in secondary schools and colleges. The similarity in the two roles is discussed, and findings that may assist learning guides to have the impact envisioned by policy-makers are highlighted. The quality of personal tutoring is dependent on the educational relationship that is created between the tutor (or learning guide) and the individual learner. Educational relationships need to provide a cordial and encouraging interchange that identifies and considers strategies for learning, criteria for success and an understanding of critical self-assessment. We suggest that an effective learning guide engages in a dialogue which focuses on personal goals, motivational factors and steps for achievement. A positive climate in personal learning sessions is characterized by challenging but realistic expectations and targets. Feedback to students should be clear and specific and stress strategies for improvement.
School culture audits: making a difference in school improvement plans
Authors: Sailes JaDora
Published: February 2008

The United States census data report that the nation is becoming more diverse at a rapid rate. Schools reflect these demographical changes by representing multiracial and multiethnic groups whose languages, religions, economics, and abilities are equally diverse. Educational systems often struggle in their efforts to support the needs of culturally different students. Consequently, these students often do not fare well academically. This article examines those factors which contribute to the achievement gap between culturally different and majority students, and describes how the cultural audit process can serve as a mechanism for addressing academic disparities.
Seeking Enlightenment on the Dark Side of Psychology
Authors: Quinsey Vernon L.
Published: February 2008

A life devoted to the study of antisocial behavior and anomalous sexual preferences is examined. Although successive ontogenetic intellectual metamorphoses have yielded theoretical and applied progress, future reincarnations will be necessary for the achievement of full enlightenment.
Longitudinal Observation of an HIV Prevention Community Planning Group (CPG)
Authors: Mejia Roberto , Jenkins Richard A. , Carey James W. , Amaro Hortensia , Morrill Allison C. , Krech Laura , Logan Jennifer A. , Cranston Kevin
Published: February 2008

HIV prevention community planning groups were formed to increase stakeholder participation and develop evidence-based comprehensive HIV prevention plans. To date, it is not well understood what factors affect group behavior as the planning group prepares for data-informed decision making. In this observational case study, the authors videotaped 18 meetings of a community planning group (CPG) to observe how a group's behavior changes over time in response to modifications in its structure and function. Discussions on authority and conflict were common, particularly during presentations on prioritized populations and interventions. Changes in the frequency of data-informed discussions were not statistically significant. Observed group conflict may have been an unintended consequence of efforts to improve equity. The authors suggest that formal and informal mechanisms to manage conflict and agreed-on procedures for decision making should be incorporated into the technical assistance offered to CPGs. Future studies should address whether data-informed decisions increase once contentious issues are resolved.
Chronic Ectopic Pregnancy
Authors: Talavera Maria D. , Horrow Mindy M.
Published: February 2008

Acute ectopic pregnancy is a common clinical problem, usually diagnosed by a combination of clinical, sonographic, and laboratory findings. Chronic ectopic pregnancy is a more unusual situation, resulting from minor ruptures that develop into a hematocele. The typical patient will have subacute or chronic pain and a low β-HCG. The sonographic findings in these cases can vary between an amorphous, avascular mass and a highly vascular complex. In the appropriate clinical setting, sonography can play an important role in the preoperative diagnosis of this entity.
Preparation, mechanical properties and wear resistance of Ni–W/SiC nanocomposite coatings
Authors: Yao Y. W. , Yao S. W. , Zhang L.
Published: February 2008

Ni–W/SiC nanocomposite coatings were prepared by electrodeposition in Ni–W plating solution containing SiC nanoparticulates. The content of co-deposited SiC in the nanocomposite coatings was controlled by the addition of different SiC nanoparticulates concentrations in the solution. The SiC nanoparticulates content in the deposit increased with the increase of its concentration in the plating bath. The mechanical property and wear resistance of Ni–W/SiC nanocomposite coatings and Ni–W alloy coating were comparatively investigated. The results indicated that addition of SiC nanoparticulates would lead to an increase in microhardness of the nanocomposite coatings. The present study shows that the co-deposited SiC nanoparticulates in deposit increase the wear resistance and reduce the wear weight loss. Moreover, the wear resistance of Ni–W/SiC nanocomposite coatings is closely related with SiC content in deposit.
Simple model for austenite grain growth in microalloyed steels
Authors: Wang H. R. , Wang W.
Published: February 2008

Previous models for grain growth are usually based on Beck's formula, which are inadequate for quantitative prediction of austenite grain growth during reheating of as cast microstructures in microalloyed steels. The applications of these empirical grain growth models are limited to some particular categories of steels, such as Nb, Nb–Ti and Ti–V microalloyed steels, etc. In this study, a metallurgically based model has been developed to predict the austenite grain growth kinetics in microalloyed steels. This model accounts for the pinning force of second phase particles on grain boundary migration, in which the mean particle size with time and temperature is calculated on the basis of the Lifshitz–Slyozov–Wagner (LSW) particle coarsening theory. The volume fraction of precipitates is obtained according to the thermodynamic model. The reliability of the model is validated by the agreement between theoretical predictions and experimental measurements in the literature.
Formation of microstructure resulting from quasi-peritectic reactions during freezing of Bi–Pb–Sn and Cu–Ni–Sn ternary alloys
Authors: Snugovsky L. , Snugovsky P. , Perovic D. D. , Rutter J. W.
Published: February 2008

The quasi-peritectic reaction, frequently observed in ternary alloy systems, takes the form L + α↔ β + γ, where L indicates the liquid phase, and α, β and γ indicate solid phases. The formation of microstructure resulting from the kinetics of this reaction is considered from a theoretical point of view and compared with experimental observations of microstructures formed by quasi-peritectic reactions in two ternary alloy systems, Bi–Pb–Sn and Cu–Ni–Sn. Based on these considerations, an explanation is proposed for experimental observations previously reported in literature concerning phase transformations from the liquid in multicomponent ferrous alloys.
Preparation and characterisation of ultrafine and uniform TiO2 nanofibres
Authors: Duan H. G. , Xie E. Q. , Zhao J. G. , Jia C. W.
Published: February 2008

Ultrafine and uniform TiO2 nanofibres were prepared by electrospinning. The morphology of the nanofibres was characterised by field emission scanning electron microscopy, which showed that the nanofibres were composed of ultrasmall nanoparticles. The structure was characterised by X-ray diffraction and resonant Raman spectrum. The optical properties of the nanofibres were characterised by photoluminescence spectrum and ultraviolet visible spectrum. The results showed that anatase phase of TiO2 formed with the nanofibres annealed at 450°C for 3 h and showed good optical characteristics.
Influence of dislocation hardening, precipitation hardening, grain elongation and sulphides on fissure formation in HSLA steels having a ferrite/pearlite microstructure
Authors: Mintz B. , Maina E. M. , Morrison W. B.
Published: February 2008

A number of examinations have been carried out on HSLA control rolled ferrite/pearlite steels to establish the influence of grain shape, precipitation hardening, dislocation hardening and inclusions on fissure formation. Grain elongation has been found to be mainly responsible. Decohesion of the grain surfaces is much more common than generally thought and occurs even in normalised steels. Warm rolling introduces dislocations into the structure and the increased strength of the matrix relative to the grain boundary strength helps to separate the grain surfaces but the main cause of fissuring is the grain elongation that occurs on warm rolling and this is enhanced the smaller the step height between the grains and the smoother the grain surfaces. Elongated austenite grains can also produce elongated ferrite grains which can also lead to fissuring.

Precipitation hardening was found to cause only a small increase in the degree of fissuring as it does not influence the grain elongation and also its strengthening effect in the steels examined was generally relatively small, not greater than 100 MPa. The sulphur content of the steel was also found to have only a small influence on fissure formation. Reducing the S content did not remove the fissures but at similar grain aspect ratios fewer fissures were produced. To produce steels that have few fissures, it is important to reduce the elongation of the ferrite or austenite grains. Since dislocation hardening is normally associated with grain elongation the favoured form of increasing the strength to meet the strength requirement in these high strength steels is to produce a uniformly fine grain size with as a low an aspect ratio as possible and to use solid solution hardening and precipitation hardening for further strengthening.
Resistance to FasL and tumor necrosis factor-related apoptosis-inducing ligand-mediated apoptosis in Sézary syndrome T-cells associated with impaired death receptor and FLICE-inhibitory protein expression
Authors: Contassot Emmanuel , Kerl Katrin , Roques Stéphanie , Shane Ryan , Gaide Olivier , Dupuis Marc , Rook Alain H. , French Lars E.
Published: February 2008

Because of the low proliferative potential of tumor cells in patients with Sézary syndrome (SzS), their accumulation has been suggested to be due to defective regulation of apoptosis. We analyzed the sensitivity to soluble Fas-ligand (FasL) and tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL), 2 members of the TNF superfamily in peripheral blood leukocytes (PBL) from patients with SzS. Compared with healthy donors, CD4+ cells from patients with SzS were completely resistant to FasL in 9 of 16 cases. Of these 9 FasL-resistant cases, 4 revealed a loss in Fas (CD95) expression, whereas the remaining 5 exhibited normal or enhanced Fas expression. In the latter 5 cases, the apoptosis inhibitor cFLIP was overexpressed in CD4+/CD26− tumor cells compared with CD4+/CD26− cells from Fas-expressing FasL-sensitive patients and healthy donors. Furthermore, resistance to TRAIL and tumor cell-restricted loss of TRAIL-receptor 2 were observed in 16 of 16 SzS PBLs. It is noteworthy that resistance to FasL could be overcome by the use of a hexameric FasL or upon exposure of SzS cells to interferon-α (IFN-α) or IFN-γ, the latter by an increase of Fas expression. Our data on primary SzS lymphocytes reveal frequent resistance to apoptosis induced by FasL and TRAIL, which may contribute to their accumulation in patients with SzS and be relevant at a therapeutic level.
Structural and numerical variation of FLT3/ITD in pediatric AML
Authors: Meshinchi Soheil , Stirewalt Derek L. , Alonzo Todd A. , Boggon Titus J. , Gerbing Robert B. , Rocnik Jennifer L. , Lange Beverly J. , Gilliland D. Gary , Radich Jerald P.
Published: February 2008

FLT3 internal tandem duplication (FLT3/ITD) is a common somatic mutation in acute myeloid leukemia (AML) with significant variation in the position, length, and number of duplications of the FLT3 gene. We evaluated these physical characteristics in FLT3/ITD-positive patients who were treated on CCG-2941/2961 and correlated them with clinical outcome. Fiftynine of 77 FLT3/ITD-positive patients (77%) had a single ITD, 16 (21%) had 2 ITDs, and 2 (3%) had 3 ITDs. The length of the duplicated region varied from 6 to 51 amino acids, and in all cases amino acid residues Y591–Y597 were duplicated. Structural analysis demonstrated that Y591–Y597 encodes the switch and zipper regions of the juxtamembrane domain of FLT3. In addition, 24 of 77 patients (31%) had duplication of the critical STAT5 docking sites Y589/591. Patients with longer ITDs had a worse relapse-free survival (19% vs 51%, P = .035), while the presence of more than 1 ITD was not clinically significant. Physical characteristics including the length of FLT3/ITD may influence FLT3 activation state by altering its structure and may impact response to therapy.
Expression of the Ladybird-like homeobox 2 transcription factor in the developing mouse testis and epididymis
Authors: Moisan Vanessa , Bomgardner Daniela , Tremblay Jacques J
Published: February 2008

Background

Homeoproteins are a class of transcription factors that are well-known regulators of organogenesis and cell differentiation in numerous tissues, including the male reproductive system. Indeed, a handful of homeoproteins have so far been identified in the testis and epididymis where a few were shown to play important developmental roles. Through a degenerate PCR approach aimed at identifying novel homeoproteins expressed in the male reproductive system, we have detected several homeoproteins most of which had never been described before in this tissue. One of these homeoproteins is Ladybird-like homeobox 2 (Lbx2), a homeobox factor mostly known to be expressed in the nervous system.

Results

To better define the expression profile of Lbx2 in the male reproductive system, we have performedin situhybridization throughout testicular and epididymal development and into adulthood. Lbx2 expression was also confirmed by real time RT-PCR in those tissues and in several testicular and epididymal cell lines. In the epididymis, a highly segmented tissue, Lbx2 shows a regionalized expression profile, being more expressed in proximal segments of the caput epididymis than any other segment. In the testis, we found that Lbx2 is constitutively expressed at high levels in Sertoli cells. In interstitial cells, Lbx2 is weakly expressed during fetal and early postnatal life, highly expressed around P32-P36, and absent in adult animals. Finally, Lbx2 can also be detected in a population of germ cells in adults.

Conclusion

Altogether, our data suggest that the homeoprotein Lbx2 might be involved in the regulation of male reproductive system development and cell differentiation as well as in male epididymal segmentation.
The PIT1 gene polymorphisms were associated with chicken growth traits
Authors: Nie Qinghua , Fang Meixia , Xie Liang , Zhou Min , Liang Zhangmin , Luo Ziping , Wang Guohuang , Bi Wensen , Liang Canjian , Zhang Wei , Zhang Xiquan
Published: February 2008

Background

With crucial roles on the differentiation of anterior pituitary and the regulation of the prolactin (PRL), growth hormone (GH) and thyroid-stimulating hormone-β (TSH-β) genes, the chicken PIT1 gene is regarded as a key candidate gene for production traits. In this study, five reported polymorphisms (MR1-MR5) of the PIT1 gene were genotyped in a full sib F2 resource population to evaluate their effects on growth, carcass and fatty traits in chickens.

Results

Marker-trait association analyses showed that, MR1 was significantly associated with shank diameters (SD) at 84 days (P < 0.05), hatch weight (HW) and shank length (SL) at 84 days (P < 0.01), MR2 was significantly associated with BW at 28, 42 days and average daily gain (ADG) at 0–4 weeks (P < 0.05), and MR3 was significantly associated with ADG at 4–8 weeks (P < 0.05). MR4 was associated with SL at 63, 77, 84 days and BW at 84 days (P < 0.05), as well as SD at 77 days (P < 0.01). Significant association was also found of MR5 with BW at 21, 35 days and SD at 63 days (P < 0.05), BW at 28 days and ADG at 0–4 weeks (P < 0.01). Both T allele of MR4 and C allele of MR5 were advantageous for chicken growth. The PIT1 haplotypes were significantly associated with HW (P = 0.0252), BW at 28 days (P = 0.0390) and SD at 56 days (P = 0.0400). No significant association of single SNP and haplotypes with chicken carcass and fatty traits was found (P > 0.05).

Conclusion

Our study found that polymorphisms of PIT1 gene and their haplotypes were associated with chicken growth traits and not with carcass and fatty traits.
New insights into the Saccharomyces cerevisiae fermentation switch: Dynamic transcriptional response to anaerobicity and glucose-excess
Authors: van den Brink Joost , Daran-Lapujade Pascale , Pronk Jack T , de Winde Johannes H
Published: February 2008

Background

The capacity of respiring cultures of Saccharomyces cerevisiae to immediately switch to fast alcoholic fermentation upon a transfer to anaerobic sugar-excess conditions is a key characteristic of Saccharomyces cerevisiae in many of its industrial applications. This transition was studied by exposing aerobic glucose-limited chemostat cultures grown at a low specific growth rate to two simultaneous perturbations: oxygen depletion and relief of glucose limitation.

Results

The shift towards fully fermentative conditions caused a massive transcriptional reprogramming, where one third of all genes within the genome were transcribed differentially. The changes in transcript levels were mostly driven by relief from glucose-limitation. After an initial strong response to the addition of glucose, the expression profile of most transcriptionally regulated genes displayed a clear switch at 30 minutes. In this respect, a striking difference was observed between the transcript profiles of genes encoding ribosomal proteins and those encoding ribosomal biogenesis components. Not all regulated genes responded with this binary profile. A group of 87 genes showed a delayed and steady increase in expression that specifically responded to anaerobiosis.

Conclusion

Our study demonstrated that, despite the complexity of this multiple-input perturbation, the transcriptional responses could be categorized and biologically interpreted. By comparing this study with public datasets representing dynamic and steady conditions, 14 up-regulated and 11 down-regulated genes were determined to be anaerobic specific. Therefore, these can be seen as true "signature" transcripts for anaerobicity under dynamic as well as under steady state conditions.
Gene array and real time PCR analysis of the adrenal sensitivity to adrenocorticotropic hormone in pig
Authors: Hazard Dominique , Liaubet Laurence , SanCristobal Magali , Mormède Pierre
Published: February 2008

Background

Variability in hypothalamic-pituitary-adrenal (HPA) axis activity has been shown to be influenced by genetic factors and related to great metabolic differences such as obesity. The aim of this study was to investigate molecular bases of genetic variability of the adrenal sensitivity to ACTH, a major source of variability, in Meishan (MS) and Large White (LW) pigs, MS being reported to exhibit higher basal cortisol levels, response to ACTH and fatness than LW. A pig cDNA microarray was used to identify changes in gene expression in basal conditions and in response to ACTH stimulation.

Results

Genotype and/or ACTH affected the expression of 211 genes related to transcription, cell growth/maintenance, signal transduction, cell structure/adhesion/extra cellular matrix and protein kinase/phosphatase activity. No change in the expression of known key regulator proteins of the ACTH signaling pathway or of steroidogenic enzymes was found. However,Mdh2,Sdha,Suclg2, genes involved in the tricarboxylic acid (TCA) pathway, were over-expressed in MS pigs. Higher TCA cycle activity in MS than in LW may thus result in higher steroidogenic activity and thus explain the typically higher cortisol levels in MS compared to LW. Moreover, up-regulation ofStarandLdlrgenes in MS and/or in response to ACTH suggest that differences in the adrenal function between MS and LW may also involve mechanisms requisite for cholesterol supply to steroidogenesis.

Conclusion

The present study provides new potential candidate genes to explain genetic variations in the adrenal sensitivity to ACTH and better understand relationship between HPA axis activity and obesity.
Structural and functional studies of a family of Dictyostelium discoideum developmentally regulated, prestalk genes coding for small proteins
Authors: Vicente Juan J , Galardi-Castilla María , Escalante Ricardo , Sastre Leandro
Published: February 2008

Background

The social amoeba Dictyostelium discoideum executes a multicellular development program upon starvation. This morphogenetic process requires the differential regulation of a large number of genes and is coordinated by extracellular signals. The MADS-box transcription factor SrfA is required for several stages of development, including slug migration and spore terminal differentiation.

Results

Subtractive hybridization allowed the isolation of a gene, sigN (SrfA-induced gene N), that was dependent on the transcription factor SrfA for expression at the slug stage of development. Homology searches detected the existence of a large family of sigN-related genes in the Dictyostelium discoideum genome. The 13 most similar genes are grouped in two regions of chromosome 2 and have been named Group1 and Group2 sigN genes. The putative encoded proteins are 87–89 amino acids long. All these genes have a similar structure, composed of a first exon containing a 13 nucleotides long open reading frame and a second exon comprising the remaining of the putative coding region. The expression of these genes is induced at10 hours of development. Analyses of their promoter regions indicate that these genes are expressed in the prestalk region of developing structures. The addition of antibodies raised against SigN Group 2 proteins induced disintegration of multi-cellular structures at the mound stage of development.

Conclusion

A large family of genes coding for small proteins has been identified in D. discoideum. Two groups of very similar genes from this family have been shown to be specifically expressed in prestalk cells during development. Functional studies using antibodies raised against Group 2 SigN proteins indicate that these genes could play a role during multicellular development.
Rapid acid treatment of Escherichia coli: transcriptomic response and recovery
Authors: Kannan Geetha , Wilks Jessica C , Fitzgerald Devon M , Jones Brian D , BonDurant Sandra S , Slonczewski Joan L
Published: February 2008

Background

Many E. coli genes show pH-dependent expression during logarithmic growth in acid (pH 5–6) or in base (pH 8–9). The effect of rapid pH change, however, has rarely been tested. Rapid acid treatment could distinguish between genes responding to external pH, and genes responding to cytoplasmic acidification, which occurs transiently following rapid external acidification. It could reveal previously unknown acid-stress genes whose effects are transient, as well as show which acid-stress genes have a delayed response.

Results

Microarray hybridization was employed to observe the global gene expression of E. coli K-12 W3110 following rapid acidification of the external medium, from pH 7.6 to pH 5.5. Fluorimetric observation of pH-dependent tetR-YFP showed that rapid external acidification led to a half-unit drop in cytoplasmic pH (from pH 7.6 to pH 6.4) which began to recover within 20 s. Following acid treatment, 630 genes were up-regulated and 586 genes were down-regulated. Up-regulated genes included amino-acid decarboxylases (cadA, adiY, gadA), succinate dehydrogenase (sdhABCD), biofilm-associated genes (bdm, gatAB, and ymgABC), and the Gad, Fur and Rcs regulons. Genes with response patterns consistent with cytoplasmic acid stress were revealed by addition of benzoate, a membrane-permeant acid that permanently depresses cytoplasmic pH without affecting external pH. Several genes (yagU, ygiN, yjeI, and yneI) were up-regulated specifically by external acidification, while other genes (fimB, ygaC, yhcN, yhjX, ymgABC, yodA) presented a benzoate response consistent with cytoplasmic pH stress. Other genes (the nuo operon for NADH dehydrogenase I, and the HslUV protease) showed delayed up-regulation by acid, with expression rising by 10 min following the acid shift.

Conclusion

Transcriptomic profiling of E. coli K-12 distinguished three different classes of change in gene expression following rapid acid treatment: up-regulation with or without recovery, and delayed response to acid. For eight genes showing acid response and recovery (fimB, ygaC, yhcN, yhjX, ymgABC, yodA), responses to the permeant acid benzoate revealed expression patterns consistent with sensing of cytoplasmic pH. The delayed acid response of nuo genes shows that NADH dehydrogenase I is probably induced as a secondary result of acid-associated metabolism, not as a direct response to cytoplasmic acidification.
Neurospheres from rat adipose-derived stem cells could be induced into functional Schwann cell-like cells in vitro
Authors: Xu Yongfeng , Liu Zhengshan , Liu Lan , Zhao Cuiping , Xiong Fu , Zhou Chang , Li Yong , Shan Yanchang , Peng Funing , Zhang Cheng
Published: February 2008

Background

Schwann cells (SC) which are myelin-forming cells in peripheral nervous system are very useful for the treatment of diseases of peripheral nervous system and central nervous system. However, it is difficult to obtain sufficient large number of SC for clinical use, so alternative cell systems are desired.

Results

Using a procedure similar to the one used for propagation of neural stem cells, we could induce rat adipose-derived stem cells (ADSC) into floating neurospheres. In addition to being able to differentiate into neuronal- and glial-like cells, neurospheres could be induced to differentiate into SC-like cells. SC-like cells were bi- or tri-polar in shape and immunopositive for nestin and SC markers p75, GFAP and S-100, identical to genuine SC. We also found that SC-like cells could induce the differentiation of SH-SY5Y neuroblastoma cells efficiently, perhaps through secretion of soluble substances. We showed further that SC-like cells could form myelin structures with PC12 cell neurites in vitro.

Conclusion

These findings indicated that ADSC could differentiate into SC-like cells in terms of morphology, phenotype and functional capacities. SC-like cells induced from ADSC may be useful for the treatment of neurological diseases.
Peer-mentoring for first-time mothers from areas of socio-economic disadvantage: A qualitative study within a randomised controlled trial
Authors: Murphy Christine A , Cupples Margaret E , Percy Andrew , Halliday Henry L , Stewart Moira C
Published: February 2008

Background

Non-professional involvement in delivering health and social care support in areas of socio-economic deprivation is considered important in attempting to reduce health inequalities. However, trials of peer mentoring programmes have yielded inconsistent evidence of benefit: difficulties in implementation have contributed to uncertainty regarding their efficacy. We aimed to explore difficulties encountered in conducting a randomised controlled trial of a peer-mentoring programme for first-time mothers in socially disadvantaged areas, in order to provide information relevant to future research and practice. This paper describes the experiences of lay-workers, women and health professionals involved in the trial.

Methods

Thematic analysis of semi-structured interviews with women (n = 11) who were offered peer mentor support, lay-workers (n = 11) who provided mentoring and midwives (n = 2) who supervised the programme, which provided support, from first hospital antenatal visit to one year postnatal. Planned frequency of contact was two-weekly (telephone or home visit) but was tailored to individuals' needs.

Results

Despite lay-workers living in the same locality, they experienced difficulty initiating contact with women and this affected their morale adversely. Despite researchers' attempts to ensure that the role of the mentor was understood clearly it appeared that this was not achieved for all participants. Mentors attempted to develop peer-mentor relationships by offering friendship and sharing personal experiences, which was appreciated by women. Mentors reported difficulties developing relationships with those who lacked interest in the programme. External influences, including family and friends, could prevent or facilitate mentoring. Time constraints in reconciling flexible mentoring arrangements with demands of other commitments posed major personal difficulties for lay-workers.

Conclusion

Difficulties in initiating contact, developing peer-mentor relationships and time constraints pose challenges to delivering lay-worker peer support. In developing such programmes, awareness of potential difficulties and of how professional support may help resolve these should improve uptake and optimise evaluation of their effectiveness.

Trial Registration Number: ISRCTN55055030
Models of asthma: density-equalizing mapping and output benchmarking
Authors: Börger Julia-Annik , Neye Niko , Scutaru Cristian , Kreiter Carolin , Puk Clemens , Fischer Tanja C , Groneberg-Kloft Beatrix
Published: February 2008

Despite the large amount of experimental studies already conducted on bronchial asthma, further insights into the molecular basics of the disease are required to establish new therapeutic approaches. As a basis for this research different animal models of asthma have been developed in the past years. However, precise bibliometric data on the use of different models do not exist so far. Therefore the present study was conducted to establish a data base of the existing experimental approaches. Density-equalizing algorithms were used and data was retrieved from a Thomson Institute for Scientific Information database. During the period from 1900 to 2006 a number of 3489 filed items were connected to animal models of asthma, the first being published in the year 1968. The studies were published by 52 countries with the US, Japan and the UK being the most productive suppliers, participating in 55.8% of all published items. Analyzing the average citation per item as an indicator for research quality Switzerland ranked first (30.54/item) and New Zealand ranked second for countries with more than 10 published studies. The 10 most productive journals included 4 with a main focus allergy and immunology and 4 with a main focus on the respiratory system. Two journals focussed on pharmacology or pharmacy. In all assigned subject categories examined for a relation to animal models of asthma, immunology ranked first. Assessing numbers of published items in relation to animal species it was found that mice were the preferred species followed by guinea pigs. In summary it can be concluded from density-equalizing calculations that the use of animal models of asthma is restricted to a relatively small number of countries. There are also differences in the use of species. These differences are based on variations in the research focus as assessed by subject category analysis.
Oxidized phospholipids reduce ventilator-induced vascular leak and inflammation in vivo
Authors: Nonas Stephanie , Birukova Anna A , Fu Panfeng , Xing Jungjie , Chatchavalvanich Santipongse , Bochkov Valery N , Leitinger Norbert , Garcia Joe GN , Birukov Konstantin G
Published: February 2008

Background

Mechanical ventilation at high tidal volume (HTV) may cause pulmonary capillary leakage and acute lung inflammation resulting in ventilator-induced lung injury. Besides blunting the Toll-like receptor-4-induced inflammatory cascade and lung dysfunction in a model of lipopolysaccharide-induced lung injury, oxidized 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (OxPAPC) exerts direct barrier-protective effects on pulmonary endothelial cells in vitro via activation of the small GTPases Rac and Cdc42. To test the hypothesis that OxPAPC may attenuate lung inflammation and barrier disruption caused by pathologic lung distension, we used a rodent model of ventilator-induced lung injury and an in vitro model of pulmonary endothelial cells exposed to pathologic mechanochemical stimulation.

Methods

Rats received a single intravenous injection of OxPAPC (1.5 mg/kg) followed by mechanical ventilation at low tidal volume (LTV) (7 mL/kg) or HTV (20 mL/kg). Bronchoalveolar lavage was performed and lung tissue was stained for histological analysis. In vitro, the effects of OxPAPC on endothelial barrier dysfunction and GTPase activation were assessed in cells exposed to thrombin and pathologic (18%) cyclic stretch.

Results

HTV induced profound increases in bronchoalveolar lavage and tissue neutrophils and in lavage protein. Intravenous OxPAPC markedly attenuated HTV-induced protein and inflammatory cell accumulation in bronchoalveolar lavage fluid and lung tissue. In vitro, high-magnitude stretch enhanced thrombin-induced endothelial paracellular gap formation associated with Rho activation. These effects were dramatically attenuated by OxPAPC and were associated with OxPAPC-induced activation of Rac.

Conclusion

OxPAPC exhibits protective effects in these models of ventilator-induced lung injury.
Construction, alignment and analysis of twelve framework physical maps that represent the ten genome types of the genus Oryza
Authors: Kim HyeRan , Hurwitz Bonnie , Yu Yeisoo , Collura Kristi , Gill Navdeep , SanMiguel Phillip , Mullikin James C , Maher Christopher , Nelson William , Wissotski Marina , Braidotti Michele , Kudrna David , Goicoechea José Luis , Stein Lincoln , Ware Doreen , Jackson Scott A , Soderlund Carol , Wing Rod A
Published: February 2008

We describe the establishment and analysis of a genus-wide comparative framework composed of 12 bacterial artificial chromosome fingerprint and end-sequenced physical maps representing the 10 genome types of Oryza aligned to the O. sativa ssp. japonica reference genome sequence. Over 932 Mb of end sequence was analyzed for repeats, simple sequence repeats, miRNA and single nucleotide variations, providing the most extensive analysis of Oryza sequence to date.
Approximate linearized inversion by optimal scaling of prestack depth migration
Authors: Symes William W.
Published: February 2008

Linearized inversion provides one possible sense of image amplitude correctness. An image or bandlimited model perturbation has correct amplitudes if it is an approximate inversion, that is, if linearized modeling (demigration), with the image as input, reproduces the data approximately. The theory of linearized acoustic inverse scattering with slowly varying background or macromodel shows that an approximate inversion may be recovered from the output of prestack depth migration by a combination of scaling and filtering. The necessary filter is completely specified by the theory, and the scale factor may be estimated via filtering, linearized modeling, a second migration, and the solution of a small auxiliary inverse problem.
Layer-thickness determination and stratigraphic interpretation using spectral inversion: Theory and application
Authors: Puryear Charles I. , Castagna John P.
Published: February 2008

Spectral inversion is a seismic method that uses a priori information and spectral decomposition to improve images of thin layers whose thicknesses are below the tuning thickness. We formulate a method to invert frequency spectra for layer thickness and apply it to synthetic and real data using complex spectral analysis. Absolute layer thicknesses significantly below the seismic tuning thickness can be determined robustly in this manner without amplitude calibration. We extend our method to encompass a generalized reflectivity series represented by a summation of impulse pairs. Application of our spectral inversion to seismic data sets from the Gulf of Mexico results in reliable well ties to seismic data, accurate prediction of layer thickness to less than half the tuning thickness, and improved imaging of subtle stratigraphic features. Comparisons between well ties for spectrally inverted data and ties for conventional seismic data illustrate the superior resolution of the former. Several stratigraphic examples illustrate the various destructive effects of the wavelet, including creating illusory geologic information, such as false stratigraphic truncations that are related to lateral changes in rock properties, and masking geologic information, such as updip limits of thin layers. We conclude that data that are inverted spectrally on a trace-by-trace basis show greater bedding continuity than do the original seismic data, suggesting that wavelet side-lobe interference produces false bedding discontinuities.
Metabolic Abnormalities Underlying the Different Prediabetic Phenotypes in Obese Adolescents
Authors: Cali' Anna M. G. , Bonadonna Riccardo C. , Trombetta Maddalena , Weiss Ram , Caprio Sonia
Published: February 2008

Objective: The aim of this study was to define the metabolic abnormalities underlying the prediabetic status of isolated impaired fasting glucose (IFG), isolated impaired glucose tolerance (IGT), and combined IFG/IGT in obese youth.

Research Design and Methods: We used state-of-the-art techniques (hyperinsulinemic-euglycemic and hyperglycemic clamps), applying a model of glucose-stimulated insulin secretion to the glucose and C-peptide concentration, in 40 normal glucose tolerance (NGT), 17 IFG, 23 IGT, and 11 IFG/IGT obese adolescents. Percent fat (by dual-energy x-ray absorptiometry), age, gender and ethnicity were comparable among groups.

Results: Peripheral insulin sensitivity was similar between the IFG and NGT groups. In contrast, the IGT and IFG/IGT groups showed marked reductions in peripheral insulin sensitivity (P < 0.002). Basal hepatic insulin resistance index (basal hepatic glucose production × fasting plasma insulin) was significantly increased in IFG, IGT, and IFG/IGT (P < 0.009) compared with NGT. Glucose sensitivity of first-phase insulin secretion was progressively lower in IFG, IGT, and IFG/IGT compared with NGT. Glucose sensitivity of second-phase secretion showed a statistically significant defect only in the IFG/IGT group. In a multivariate regression analysis, glucose sensitivity of first-phase secretion and basal insulin secretion rate were significant independent predictors of FPG (total r2 = 25.9%).

Conclusions: IFG, in obese adolescents, is linked primarily to alterations in glucose sensitivity of first-phase insulin secretion and liver insulin sensitivity. The IGT group is affected by a more severe degree of peripheral insulin resistance and reduction in first-phase secretion. IFG/IGT is hallmarked by a profound insulin resistance and by a new additional defect in second-phase insulin secretion.
Elevated Midpregnancy Corticotropin-Releasing Hormone Is Associated with Prenatal, But Not Postpartum, Maternal Depression
Authors: Rich-Edwards J. W. , Mohllajee A. P. , Kleinman K. , Hacker M. R. , Majzoub J. , Wright R. J. , Gillman M. W.
Published: February 2008

Context: Elevated hypothalamic CRH has been implicated in melancholic major depression in nonpregnant individuals, but the role of placental CRH in maternal prenatal and postpartum depression is largely unexplored.

Objective: The objective of the study was to examine the association of maternal midpregnancy plasma CRH levels with prenatal and postpartum depression.

Participants: The study included 800 participants in Project Viva, a pregnancy and childhood cohort.

Methods: CRH levels were analyzed from blood samples obtained at mean 27.9 wk gestation (± 1.3 sd; range 24.6–37.4 wk) and were normalized on the logarithmic scale. Depression was assessed with the Edinburgh Postpartum Depression Scale (range 0–30 points) in midpregnancy and at 6 months postpartum. We used logistic regression to estimate the odds of scoring 13 or more points on the Edinburgh Postpartum Depression Scale as indicative of major or minor depression.

Results: Seventy (8.8%) and 46 (7.5%) women had prenatal and postpartum depression symptoms, respectively. Mean log CRH was 4.93 (± 0.62 sd). After adjusting for confounders, an sd increase in log CRH was associated with nearly 50% higher odds of prenatal depression symptoms (odds ratio 1.48, 95% confidence interval 1.14–1.93). Higher CRH levels during pregnancy were unassociated with greater risk of postpartum depressive symptoms. In fact, there was a suggestion that prenatal CRH levels might be inversely associated with risk of postpartum depressive symptoms (odds ratio 0.82, 95% confidence interval 0.58–1.15).

Conclusions: Elevated placental CRH levels in midpregnancy are positively associated with risk of prenatal depression symptoms but not postpartum depression symptoms.
Grainy head promotes expression of septate junction proteins and influences epithelial morphogenesis
Authors: Narasimha Maithreyi , Uv Anne , Krejci Alena , Brown Nicholas H. , Bray Sarah J.
Published: February 2008

Transcription factors of the Grainy head (Grh) family are required in epithelia to generate the impermeable apical layer that protects against the external environment. This function is conserved in vertebrates and invertebrates, despite the differing molecular composition of the protective barrier. Epithelial cells also have junctions that create a paracellular diffusion barrier (tight or septate junctions). To examine whether Grh has a role in regulating such characteristics, we used an epidermal layer in the Drosophila embryo that has no endogenous Grh and lacks septate junctions, the amnioserosa. Expression of Grh in the amnioserosa caused severe defects in dorsal closure, a process similar to wound closure, and induced robust expression of the septate junction proteins Coracle, Fasciclin 3 and Sinuous. Grh-binding sites are present within the genes encoding these proteins, consistent with them being direct targets. Removal of Grh from imaginal disc cells caused a reduction in Fasciclin 3 and Coracle levels, suggesting that Grh normally fine tunes their epithelial expression and hence contributes to barrier properties. The fact that ectopic Grh arrests dorsal closure also suggests that this dynamic process relies on epithelia having distinct adhesive properties conferred by differential deployment of Grh.
Distinct endocytic recycling of myelin proteins promotes oligodendroglial membrane remodeling
Authors: Winterstein Christine , Trotter Jacqueline , Krämer-Albers Eva-Maria
Published: February 2008

The central nervous system myelin sheath is a multilayered specialized membrane with compacted and non-compacted domains of defined protein composition. How oligodendrocytes regulate myelin membrane trafficking and establish membrane domains during myelination is largely unknown. Oligodendroglial cells respond to neuronal signals by adjusting the relative levels of endocytosis and exocytosis of the major myelin protein, proteolipid protein (PLP). We investigated whether endocytic trafficking is common to myelin proteins and analyzed the endocytic fates of proteins with distinct myelin subdomain localization. Interestingly, we found that PLP, myelin-associated glycoprotein (MAG) and myelin-oligodendrocyte glycoprotein (MOG), which localize to compact myelin, periaxonal loops and abaxonal loops, respectively, exhibit distinct endocytic fates. PLP was internalized via clathrin-independent endocytosis, whereas MAG was endocytosed by a clathrin-dependent pathway, although both proteins were targeted to the late-endosomal/lysosomal compartment. MOG was also endocytosed by a clathrin-dependent pathway, but in contrast to MAG, trafficked to the recycling endosome. Endocytic recycling resulted in the association of PLP, MAG and MOG with oligodendroglial membrane domains mimicking the biochemical characteristics of myelin domains. Our results suggest that endocytic sorting and recycling of myelin proteins may assist plasma membrane remodeling, which is necessary for the morphogenesis of myelin subdomains.
L- and S-endoglin differentially modulate TGFβ1 signaling mediated by ALK1 and ALK5 in L6E9 myoblasts
Authors: Velasco Soraya , Alvarez-Muñoz Patricia , Pericacho Miguel , Dijke Peter ten , Bernabéu Carmelo , López-Novoa José M. , Rodríguez-Barbero Alicia
Published: February 2008

TGFβ regulates cellular processes by binding to type I and type II TGFβ receptors (TβRI and TβRII, respectively). In addition to these signaling receptors, endoglin is an accessory TGFβ receptor that regulates TGFβ signaling. Although there are two different alternatively spliced isoforms of endoglin, L-endoglin (L, long) and S-endoglin (S, short), little is known about the effects of S-endoglin isoform on TGFβ signaling. Here, we have analyzed the TGFβ1 signaling pathways and the effects of L- and S-endoglin in endoglin-deficient L6E9 cells. We found that TGFβ activates two distinct TβRI-Smad signaling pathways: ALK1-Smad1-Id1 and ALK5-Smad2-PAI1, in these cells. Interestingly, L-endoglin enhanced the ALK1-Id1 pathway, while S-endoglin promoted the ALK5-PAI1 route. These effects on signaling are supported by biological effects on TGFβ1-induced collagen I expression and inhibition of cell proliferation. Thus, while L-endoglin decreased TGFβ1-induced collagen I and CTGF expression and increased TGFβ1-induced proliferation, S-endoglin strongly increased TGFβ1-induced collagen I and CTGF expression, and reduced TGFβ1-induced cell proliferation.
Fibrogenic fibroblasts increase intercellular adhesion strength by reinforcing individual OB-cadherin bonds
Authors: Pittet Philippe , Lee Kyumin , Kulik Andrzej J. , Meister Jean-Jacques , Hinz Boris
Published: February 2008

We have previously shown that the switch from N-cadherin to OB-cadherin expression increases intercellular adhesion between fibroblasts during their transition from a migratory to a fibrogenic phenotype. Using atomic force microscopy we here show that part of this stronger adhesion is accomplished because OB-cadherin bonds resist ∼twofold higher forces compared with N-cadherin junctions. By assessing the adhesion force between recombinant cadherin dimers and between native cadherins in the membrane of spread fibroblasts, we demonstrate that cadherin bonds are reinforced over time with two distinct force increments. By modulating the degree of lateral cadherin diffusion and F-actin organization we can attribute the resulting three force states to the single-molecule bond rather than to cadherin cluster formation. Notably, association with actin filaments enhances cadherin adhesion strength on the single-molecule level up to threefold; actin depolymerization reduces single-bond strength to the level of cadherin constructs missing the cytoplasmic domain. Hence, fibroblasts reinforce intercellular contacts by: (1) switching from N- to OB-cadherin expression; (2) increasing the strength of single-molecule bonds in three distinct steps; and (3) actin-promoted intrinsic activation of cadherin extracellular binding. We propose that this plasticity adapts fibroblast adhesions to the changing mechanical microenvironment of tissue under remodeling.
Synthesis of a Molecular Container Having an Open Door that Closes on Guest Binding
Authors: Haino Takeharu , Hirakata Masaki , Niimi Kahoru , Kouchi Mitsuru , Iwamoto Hajime , Fukazawa Yoshimasa
Published: February 2008

A molecular container composed of monodeoxy-calix[4]arene and calix[4]arene is synthesized. The host binds planar cationic guests. The deoxy-aromatic ring acts as an open door when the guest is absent and closes on guest binding.