bluuebunny/crossref_metadata_2025 huggingface dataset:
International students of Speech and Language Therapy in the UK: do we meet their needs?
Authors: Marshall Julie , Goldbart Juliet , Evans Ruth
Published: March 2004

Background: Informal evidence suggests that many Speech and Language Therapy (SLT) students from outside of the UK and/or Republic of Ireland who come to the UK either do not return to their home country on qualification or do not practise as SLTs in the public sector. Many factors may contribute to this situation. Concern that it may result in part from a poor match between UK SLT education and the demands of the role in other countries led the Royal College of Speech and Language Therapists (RCSLT) to fund a study of international SLT students' experiences of UK qualifying courses.

Aims: To discover and describe the experiences, views and expectations of current and past international students studying SLT in the UK and past international students' experiences, views and expectations of practising as SLTS, both inside and outside the UK. To consider the implications of the findings for (1) international students planning to work as SLTs; (2) UK SLT students planning to practise outside the UK; and (3) all those involved in SLT education: educational institutions; supervising SLTs; RCSLT.

Methods & Procedures: The study involved distributing 166 postal questionnaires (some directly to (ex)students and some to their Higher Education Institutes, or HEIs) and carrying out 23 interviews, with both current students and those qualifying since May 1994. Quantitative analysis was carried out using SPSS using descriptive statistics. Qualitative analysis used content and thematic analyses.

Outcomes & Results: Seventy‐one questionnaires were received from current and past students, representing a minimum response rate of 43%. (It was not possible to verify exactly how many questionnaires were distributed by HEIs.) The results describe the diverse range of respondents' experiences of studying and working in the UK, their views of working in their home countries and the UK, and their suggestions about strategies that might be adopted to support them further. The results revealed that students come from a wide diversity of countries, with resulting differences in their experiences. However, there were some commonalities in the perceived advantages and disadvantages of working at home and in the UK.

Conclusions: The suggestions for change included practical ideas for change both before and after qualification as an SLT. These included courses about the organization of health, education and social services in the UK, adaptations of course delivery and course work to include cross‐cultural/linguistic work and ‘home‐based’ projects. Implications of the findings and strategies for home as well as international SLT students are discussed.
Children's Communication Checklist (CCC) scores in 11‐year‐old children with communication impairments
Authors: Botting Nicola
Published: March 2004

Background: The pragmatic skills of children with communication disorders and their assessment are currently an issue for speech and language therapy and educational placement.

Aims: To explore whether different subgroups of children with communication disorders score differently on the Children's Communication Checklist (CCC) and to study how they compare with published normative data.

Methods & Procedures: A sample of 161 eleven‐year‐old children with a history of communication disorders was assessed using the CCC. The main use of this questionnaire was to establish whether pragmatic impairments were part of a child's communication difficulty. Although the checklist was originally designed for research purposes, normative data for this scale have been recently published as well as group data from a number of different clinical groups. Whilst the present CCC data have been previously reported descriptively for a wider sample, they have not been examined in terms of subgroups or compared directly with normative information and similarly diagnosed individuals from other studies.

Outcomes & Results: Of the children assessed, 52 (33%) scored in the normal range (within 1 SD) on the pragmatic scale, 40 (26%) fell between 1 and 2 SD below the normative mean, and 64 (41%) scored below 2 SD of the mean of typically developing children (aged 6–16 years). Thus, the majority (67%) scored out of the normal range for pragmatic skill at 11 years of age. The cohort was separated into four diagnostic subcategories: those with a definite diagnosis of autistic spectrum disorder (n=15); those with typical specific language impairment (n=82); generally impaired (n=37); and those with a clinical history of primary pragmatic language impairment (independent of CCC score, n=27).

Conclusions: Findings show that those generally impaired and with specific language impairment were less impaired than the other groups on the CCC pragmatic scale. There was a significant trend for those with autistic spectrum disorders to score lowest through pragmatic language impairment, generally impairment to specific language impairment. It is argued that a cut‐off of 140 may prove more useful at this age than the 132 level previously published for 8 year olds. Results suggest that the CCC can be used as a clinical tool, but in conjunction with other reliable measures.
Literacy outcomes for students with speech impairment: long‐term follow‐up
Authors: Leitao Suze , Fletcher Janet
Published: March 2004

Background: Theoretical and empirical support now exists for the finding that many children with expressive phonological impairment experience problems in acquiring phonological awareness and early literacy skills. Few studies, however, have examined the long‐term academic and literacy outcomes for this population, in particular as the students leave the final stages of primary school.

Aims: The reported study forms the final stage of a longitudinal research project that tracked the phonological processing and literacy skills of a group of children with specific speech impairment from their first year at school (aged 5–6 years). The earlier data provided evidence of a relationship between speech impairment characterized by the presence of non‐developmental error processes and weaker phonological awareness and literacy skills in the first 2–3 years at school. It was hypothesized that the effect of this relationship would continue to be apparent as the students completed the final stages of primary school.

Methods & Procedures: Fourteen of the original set of 36 students were available for reassessment of their phonological processing, reading and spelling skills at age 12–13 years.

Outcomes & Results: Those children with an original classification of non‐developmental speech errors performed significantly more poorly than those with an original classification of developmental errors on phonological awareness and reading comprehension measures. Reading accuracy and spelling scores also showing a similar trend.

Conclusions: These findings provide further evidence for the long‐term impact of speech impairment. The follow‐up data demonstrated ongoing difficulties for students who entered school with expressive speech impairment, particularly those whose speech errors were characterized by non‐developmental error processes. The impact was apparent on tasks measuring phonological awareness, reading accuracy and spelling (skills that depend on good phonological processing skills and clear underlying phonological representations). Weaknesses in reading comprehension were also found. These findings have implications for the early identification of those at risk. In addition, intervention approaches for young children with expressive speech difficulties demonstrating these patterns of error should address weak underlying phonological representations and develop phonological awareness skills.
Interaction training for conversational partners of children with cerebral palsy: a systematic review
Authors: Pennington Lindsay , Goldbart Juliet , Marshall Julie
Published: March 2004

Background: Research has shown that children with cerebral palsy have difficulties acquiring communication skills and that conversation with familiar partners follows restricted patterns, which are characterized by high levels of partner control and children's responsivity. Speech and language therapy often includes training for conversational partners to help to them recognize children's communicative signals and to create opportunities for children to take a more equal and independent role in conversation. However, the effectiveness of this indirect therapy has not been demonstrated reliably.

Aims: To review systematically all experimental research on communication training for conversational partners of children with cerebral palsy and to evaluate the effectiveness of this type of intervention.

Methods & Procedures: As part of a wider review, health, psychology and education electronic databases were searched up to December 2002 for reports of experimental studies on the training of conversational partners to facilitate the communication of children with cerebral palsy, which contained an element of control. References from identified studies were followed‐up and relevant journals and conference reports were hand‐searched. Identified studies were assessed for inclusion by the first author. Two reviewers independently abstracted data on the quality and content of each study.

Outcomes & Results: Four studies were identified from five research reports that met the criteria for inclusion in the review, comprising three group studies and one single case experiment. Common targets for training were observed across the studies. These included positioning of the conversational partner and child for interaction, creating communication opportunities and responding to children's communicative signals. Changes were observed in the conversation patterns used by conversational partners, which should facilitate the communication of children with cerebral palsy. However, the studies contain methodological flaws and as a result they cannot demonstrate that the changes were definitely a result of the intervention.

Conclusions: Research on the effectiveness of interaction training for conversational partners of children with cerebral palsy is in its early stages. Training has incorporated common targets, which are widely acknowledged by clinicians to affect the communication of children with motor disorders. Trends in behaviour change have been suggested by research to date, but further studies that address the methodological inadequacies of the original research are needed to evaluate the effectiveness of this type of intervention. Suggestions of ways to improve the design and reporting of future studies, that will allow the mapping of interventions to clients, are discussed in this review.
Dismantling the Lidcombe Program of early stuttering intervention: verbal contingencies for stuttering and clinical measurement
Authors: Harrison Elisabeth , Onslow Mark , Menzies Ross
Published: March 2004

Background: Data have accumulated to show that the Lidcombe Program of early stuttering intervention is a safe treatment with positive outcomes for preschoolers who stutter, and a randomized controlled trial is under way at the time of writing. Program components have not been investigated experimentally so the functionality of each component is unknown.

Aims: The aim of this preliminary study was to establish the viability of a programme of research that would assess the clinical value of two program components. These components were parental verbal contingencies for stuttering and severity ratings.

Methods & Procedures: In the present preliminary experiment, 38 preschool children were randomized to an experiment involving a 4‐week ‘dose’ of treatment followed by 4 weeks without treatment. The dependent variable was the percentage of syllables stuttered (%SS) obtained from the mean %SS score from recordings on three recording occasions.

Outcomes & Results: Some preliminary indications were found that parental verbal contingencies for stuttering contributed to treatment outcomes. No preliminary evidence was found for the contribution of parent severity ratings to treatment outcomes.

Conclusions: It was concluded that a robust, statistical demonstration of these result would be desirable, but effect size estimates from the present data show that access to more than 650 families of stuttering preschool children would be required for such a study. Such a project would be beyond the resources of any one research group to complete in a timely manner, and a method to address this problem is proposed.
Protection from the Dark Side of NO: Signaling and Cellular Defenses Against Nitric Oxide Toxicity
Authors: Demple Bruce
Published: March 2004

Although it is employed in biological systems for intercellular signaling or inflammatory responses, nitric oxide is not readily contained by cell membranes and so might damage surrounding non‐target cells. We have studied the genetic and biochemical basis of cellular resistance to the toxicity of NO. Inducible resistance mechanisms activate defense pathways that diminish lethal damage, prevent apoptosis, and may employ increased repair systems. A key inducible component of the cell response to NO toxicity is the enzyme heme oxygenase‐1 (HO1). The activity of HO1 is necessary for the basic resistance of mammalian cells to NO‐mediated cytotoxicity. However, the critical HO1‐dependent reaction(s) responsible for NO resistance have not yet been identified. The induction of HO1 in response to NO depends on limited transcriptional activation and, in some cell types, on dramatic NO‐induced stabilization of the HO1 mRNA. In human fibroblasts, this stabilization increases directly with the degree of NO exposure. Novel regulatory pathways appear to underlie the pathways of inducible NO resistance and NO‐mediated mRNA stability.
IUBMB Life, 56: 59‐64, 2004
Aneuploidy, the Primary Cause of the Multilateral Genomic Instability of Neoplastic and Preneoplastic Cells
Authors: Duesberg Peter , Fabarius Alice , Hehlmann Ruediger
Published: March 2004

Cancers have a clonal origin, yet their chromosomes and genes are non‐clonal or heterogeneous due to an inherent genomic instability. However, the cause of this genomic instability is still debated. One theory postulates that mutations in genes that are involved in DNA repair and in chromosome segregation are the primary causes of this instability. But there are neither consistent correlations nor is there functional proof for the mutation theory. Here we propose aneuploidy, an abnormal number of chromosomes, as the primary cause of the genomic instability of neoplastic and preneoplastic cells. Aneuploidy destabilizes the karyotype and thus the species, independent of mutation, because it corrupts highly conserved teams of proteins that segregate, synthesize and repair chromosomes. Likewise it destabilizes genes. The theory explains 12 of 12 specific features of genomic instability: (1) Mutagenic and non‐mutagenic carcinogens induce genomic instability via aneuploidy. (2) Aneuploidy coincides and segregates with preneoplastic and neoplastic genomic instability. (3) Phenotypes of genomically unstable cells change and even revert at high rates, compared to those of diploid cells, via aneuploidy‐catalyzed chromosome rearrangements. (4) Idiosyncratic features of cancers, like immortality and drug‐resistance, derive from subspecies within the 'polyphyletic' diversity of individual cancers. (5) Instability is proportional to the degree of aneuploidy. (6) Multilateral chromosomal and genetic instabilities typically coincide, because aneuploidy corrupts multiple targets simultaneously. (7) Gene mutation is common, but neither consistent nor clonal in cancer cells as predicted by the aneuploidy theory. (8) Cancers fall into a near‐diploid (2 N) class of low instability, a near 1.5 N class of high instability, or a near 3 N class of very high instability, because aneuploid fitness is maximized either by minimally unstable karyotypes or by maximally unstable, but adaptable karyotypes. (9) Dominant phenotypes, because of aneuploid genotypes. (10) Uncertain developmental phenotypes of Down and other aneuploidy syndromes, because supply‐sensitive, diploid programs are destabilized by products from aneuploid genes supplied at abnormal concentrations; the maternal age‐bias for Down's would reflect age‐dependent defects of the spindle apparatus of oocytes. (11) Non‐selective phenotypes, e.g., metastasis, because of linkage with selective phenotypes on the same chromosomes. (12) The target, induction of genomic instability, is several 1000‐fold bigger than gene mutation, because it is entire chromosomes. The mutation theory explains only a few of these features. We conclude that the transition of stable diploid to unstable aneuploid cell species is the primary cause of preneoplastic and neoplastic genomic instability and of cancer, and that mutations are secondary.
IUBMB Life, 56: 65‐81, 2004
Intracellular Proteins and Mechanisms Involved in the Control of gp130/JAK/STAT Cytokine Signaling
Authors: Carbia‐Nagashima Alberto , Arzt Eduardo
Published: March 2004

Cytokines regulate many cellular responses such as proliferation, differentiation and survival and play regulatory roles in numerous organ systems. The cytokines of the IL‐6 family use the membrane glycoprotein gp130 as a signal transducer and signal through the JAK/STAT pathway. As they share a common signal transducer they show some functional redundancy but also exhibit specific biological activities. Considering that gp130 is ubiquitously expressed, the time and place at which gp130 functions in vivo appears to be determined by spatially and chronologically regulated expression of specific cytokine‐binding receptor chains or cytokines themselves. The study of transgenic and knock‐out mice for different members of the gp130 signaling cascade has revealed they are critical in embryo development and play a role in physiological responses as diverse as hematopoiesis, the inflammatory response, nervous system development and survival and myocardial and pituitary proliferation. gp130 cytokines have also been implicated in cellular transformation and the pathophysiology of many tumors. Recently, two new families of proteins that function as negative regulators of cytokine signaling, SOCS and PIAS, have been extensively studied and could be new targets for the treatment of pathologies originated by gp130 signaling disregulation. The ubiquitin‐proteosome pathway and the new ubiquitin‐like protein SUMO‐1 seem to play an important role in SOCS and PIAS mediated inhibition but the mechanisms still remain to be elucidated.
IUBMB Life, 56: 83‐88, 2004
Structural Aspects of MicroRNA Biogenesis
Authors: Krol Jacek , Krzyzosiak Wlodzimierz J.
Published: March 2004

One of the biggest surprises at the beginning of the 'post‐genome era' was the discovery of numerous genes encoding microRNAs. They were found in genomes of such diverse organisms as Caenorhabditis elegans, Drosophila melanogaster, Arabidopsis thaliana, and Homo sapiens which implies their important role in multicellular life evolution. The number of microRNA genes is estimated to be nearly 1% of that of protein‐coding genes. Their products, tiny RNAs, are thought to regulate gene expression during development, organogenesis, and very likely during many other processes, by hybridizing to their target mRNAs. The cellular functions of mRNAs that are regulated by microRNAs are only beginning to be revealed, and details of this regulation mechanism are still poorly understood. In this article we discuss the possible mechanisms of microRNA biogenesis with special emphasis on their structural aspects. We have focused on the factors and effects that may be responsible for the existing length differences between different microRNAs, and for the observed length heterogeneity within some individual microRNA species.
IUBMB Life, 56: 95‐100, 2004
Total Antioxidant Levels are Low During Active TB and Rise with Anti‐tuberculosis Therapy
Authors: Wiid I. , Seaman T. , Hoal EG , Benade AJS , Van Helden Paul D.
Published: March 2004

In tuberculosis, oxidative stress is a result of tissue inflammation, poor dietary intake of micronutrients due to illness, free radical burst from activated macrophages, and anti‐tuberculosis drugs. These free radicals may in turn contribute towards pulmonary inflammation if not neutralized by antioxidants. The total antioxidant status (TAS) of individuals is a function of dietary, enzymatic, and other systemic antioxidants and is therefore an indicator of the free radical load. Our aim was to evaluate the TAS of healthy and M. tuberculosis‐infected persons from a high TB incidence community, as well as tuberculosis patients at various stages of antituberculosis drug treatment and to correlate results with plasma micronutrient levels. Blood plasma samples from TB infected patients and following antituberculosis drug treatment were assayed for TAS, vitamins A, E and Zinc. Statistical analysis of results was by one‐way ANOVA and the Tukey multiple comparison post test. Active TB patients showed a significantly lower TAS (P < 0.001) compared to the community controls. We also show that TAS values increase during therapy. Results correlated with micronutrients vitamin A and zinc but vitamin E remained unaffected. We suggest that total antioxidant status of TB patients should be considered for more effective disease control and that diets low in antioxidants may render individuals susceptible to tuberculosis.
IUBMB Life, 56: 101‐106, 2004
Cortactin is necessary for E-cadherin–mediated contact formation and actin reorganization
Authors: Helwani Falak M. , Kovacs Eva M. , Paterson Andrew D. , Verma Suzie , Ali Radiya G. , Fanning Alan S. , Weed Scott A. , Yap Alpha S.
Published: March 2004

Classical cadherin adhesion molecules are key determinants of cell–cell recognition during development and in post-embryonic life. A decisive step in productive cadherin-based recognition is the conversion of nascent adhesions into stable zones of contact. It is increasingly clear that such contact zone extension entails active cooperation between cadherin adhesion and the force-generating capacity of the actin cytoskeleton. Cortactin has recently emerged as an important regulator of actin dynamics in several forms of cell motility. We now report that cortactin is recruited to cell–cell adhesive contacts in response to homophilic cadherin ligation. Notably, cortactin accumulates preferentially, with Arp2/3, at cell margins where adhesive contacts are being extended. Recruitment of cortactin is accompanied by a ligation-dependent biochemical interaction between cortactin and the cadherin adhesive complex. Inhibition of cortactin activity in cells blocked Arp2/3-dependent actin assembly at cadherin adhesive contacts, significantly reduced cadherin adhesive contact zone extension, and perturbed both cell morphology and junctional accumulation of cadherins in polarized epithelia. Together, our findings identify a necessary role for cortactin in the cadherin–actin cooperation that supports productive contact formation.
Nesca, a novel adapter, translocates to the nuclear envelope and regulates neurotrophin-induced neurite outgrowth
Authors: MacDonald James I.S. , Kubu Chris J. , Meakin Susan O.
Published: March 2004

We provide the first characterization of a novel signaling adapter, Nesca, in neurotrophic signal transduction. Nesca contains a RUN domain, a WW domain, a leucine zipper, a carboxyl-terminal SH3 domain, and several proline-rich regions. Nesca is highly expressed in the brain, is serine phosphorylated, and mobilizes from the cytoplasm to the nuclear membrane in response to neurotrophin, but not epidermal growth factor, stimulation in a MEK-dependent process. Overexpression studies in PC12 cells indicate that Nesca facilitates neurotrophin-dependent neurite outgrowth at nonsaturating doses of nerve growth factor (NGF). Similarly, short interfering RNA studies significantly reduce NGF-dependent neuritogenesis in PC12 cells. Mutational analyses demonstrate that the RUN domain is an important structural determinant for the nuclear translocation of Nesca and that the nuclear redistribution of Nesca is essential to its neurite outgrowth-promoting properties. Collectively, these works provide the first functional characterization of Nesca in the context of neurotrophin signaling and suggest that Nesca serves a novel, nuclear-dependent role in neurotrophin-dependent neurite outgrowth.
Tumor cell α3β1 integrin and vascular laminin-5 mediate pulmonary arrest and metastasis
Authors: Wang Hui , Fu Weili , Im Jae Hong , Zhou Zengyi , Santoro Samuel A. , Iyer Vandana , DiPersio C. Mike , Yu Qian-Chun , Quaranta Vito , Al-Mehdi Abu , Muschel Ruth J.
Published: March 2004

Arrest of circulating tumor cells in distant organs is required for hematogenous metastasis, but the tumor cell surface molecules responsible have not been identified. Here, we show that the tumor cell α3β1 integrin makes an important contribution to arrest in the lung and to early colony formation. These analyses indicated that pulmonary arrest does not occur merely due to size restriction, and raised the question of how the tumor cell α3β1 integrin contacts its best-defined ligand, laminin (LN)-5, a basement membrane (BM) component. Further analyses revealed that LN-5 is available to the tumor cell in preexisting patches of exposed BM in the pulmonary vasculature. The early arrest of tumor cells in the pulmonary vasculature through interaction of α3β1 integrin with LN-5 in exposed BM provides both a molecular and a structural basis for cell arrest during pulmonary metastasis.
An actin molecular treadmill and myosins maintain stereocilia functional architecture and self-renewal
Authors: Rzadzinska Agnieszka K. , Schneider Mark E. , Davies Caroline , Riordan Gavin P. , Kachar Bechara
Published: March 2004

We have previously shown that the seemingly static paracrystalline actin core of hair cell stereocilia undergoes continuous turnover. Here, we used the same approach of transfecting hair cells with actin–green fluorescent protein (GFP) and espin-GFP to characterize the turnover process. Actin and espin are incorporated at the paracrystal tip and flow rearwards at the same rate. The flux rates (∼0.002–0.04 actin subunits s−1) were proportional to the stereocilia length so that the entire staircase stereocilia bundle was turned over synchronously. Cytochalasin D caused stereocilia to shorten at rates matching paracrystal turnover. Myosins VI and VIIa were localized alongside the actin paracrystal, whereas myosin XVa was observed at the tips at levels proportional to stereocilia lengths. Electron microscopy analysis of the abnormally short stereocilia in the shaker 2 mice did not show the characteristic tip density. We argue that actin renewal in the paracrystal follows a treadmill mechanism, which, together with the myosins, dynamically shapes the functional architecture of the stereocilia bundle.
A role for the actin cytoskeleton in cell death and aging in yeast
Authors: Gourlay Campbell W. , Carpp Lindsay N. , Timpson Paul , Winder Steven J. , Ayscough Kathryn R.
Published: March 2004

Several determinants of aging, including metabolic capacity and genetic stability, are recognized in both yeast and humans. However, many aspects of the pathways leading to cell death remain to be elucidated. Here we report a role for the actin cytoskeleton both in cell death and in promoting longevity. We have analyzed yeast strains expressing mutants with either increased or decreased actin dynamics. We show that decreased actin dynamics causes depolarization of the mitochondrial membrane and an increase in reactive oxygen species (ROS) production, resulting in cell death. Important, however, is the demonstration that increasing actin dynamics, either by a specific actin allele or by deletion of a gene encoding the actin-bundling protein Scp1p, can increase lifespan by over 65%. Increased longevity appears to be due to these cells producing lower than wild-type levels of ROS. Homology between Scp1p and mammalian SM22/transgelin, which itself has been isolated in senescence screens, suggests a conserved mechanism linking aging to actin stability.
Protein kinase Cι is required for Ras transformation and colon carcinogenesis in vivo
Authors: Murray Nicole R. , Jamieson Lee , Yu Wangsheng , Zhang Jie , Gökmen-Polar Yesim , Sier Deborah , Anastasiadis Panos , Gatalica Zoran , Thompson E. Aubrey , Fields Alan P.
Published: March 2004

Protein kinase C ι (PKCι) has been implicated in Ras signaling, however, a role for PKCι in oncogenic Ras-mediated transformation has not been established. Here, we show that PKCι is a critical downstream effector of oncogenic Ras in the colonic epithelium. Transgenic mice expressing constitutively active PKCι in the colon are highly susceptible to carcinogen-induced colon carcinogenesis, whereas mice expressing kinase-deficient PKCι (kdPKCι) are resistant to both carcinogen- and oncogenic Ras-mediated carcinogenesis. Expression of kdPKCι in Ras-transformed rat intestinal epithelial cells blocks oncogenic Ras-mediated activation of Rac1, cellular invasion, and anchorage-independent growth. Constitutively active Rac1 (RacV12) restores invasiveness and anchorage-independent growth in Ras-transformed rat intestinal epithelial cells expressing kdPKCι. Our data demonstrate that PKCι is required for oncogenic Ras- and carcinogen-mediated colon carcinogenesis in vivo and define a procarcinogenic signaling axis consisting of Ras, PKCι, and Rac1.
In vivo kinetics of Cajal body components
Authors: Dundr Miroslav , Hebert Michael D. , Karpova Tatiana S. , Stanek David , Xu Hongzi , Shpargel Karl B. , Meier U. Thomas , Neugebauer Karla M. , Matera A. Gregory , Misteli Tom
Published: March 2004

Cajal bodies (CBs) are subnuclear domains implicated in small nuclear ribonucleoprotein (snRNP) biogenesis. In most cell types, CBs coincide with nuclear gems, which contain the survival of motor neurons (SMN) complex, an essential snRNP assembly factor. Here, we analyze the exchange kinetics of multiple components of CBs and gems in living cells using photobleaching microscopy. We demonstrate differences in dissociation kinetics of CB constituents and relate them to their functions. Coilin and SMN complex members exhibit relatively long CB residence times, whereas components of snRNPs, small nucleolar RNPs, and factors shared with the nucleolus have significantly shorter residence times. Comparison of the dissociation kinetics of these shared proteins from either the nucleolus or the CB suggests the existence of compartment-specific retention mechanisms. The dynamic properties of several CB components do not depend on their interaction with coilin because their dissociation kinetics are unaltered in residual nuclear bodies of coilin knockout cells. Photobleaching and fluorescence resonance energy transfer experiments demonstrate that coilin and SMN can interact within CBs, but their interaction is not the major determinant of their residence times. These results suggest that CBs and gems are kinetically independent structures.
Positive Selection of B Cells Expressing Low Densities of Self-reactive BCRs
Authors: Gaudin Emmanuelle , Hao Yi , Rosado Maria Manuela , Chaby Richard , Girard Robert , Freitas António A.
Published: March 2004

B cell tolerance or autoimmunity is determined by selective events. Negative selection of self-reactive B cells is well documented and proven. In contrast, positive selection of conventional B cells is yet to be firmly established. Here, we demonstrate that developing self-reactive B cells are not always highly sensitive to the deletion mechanisms imposed by membrane-bound self-antigens. At low amounts, membrane-bound antigens allow survival of B cells bearing a single high affinity self-reactive B cell receptor (BCR). More importantly, we show that forced allelic inclusion modifies B cell fate; low quantities of self-antigen induce the selection and accumulation of increased numbers of self-reactive B cells with decreased expression of antigen-specific BCRs. By directly measuring antigen binding by intact B cells, we show that the low amounts of self-antigen select self-reactive B cells with a lower association constant. A fraction of these B cells is activated and secretes autoantibodies that form circulating immune complexes with self-antigen. These findings demonstrate that conventional B cells can undergo positive selection and that the fate of a self-reactive B cell depends on the quantity of self-antigen, the number of BCRs engaged, and on its overall antigen-binding avidity, rather than on the affinity of individual BCRs.
PKCθ Signals Activation versus Tolerance In Vivo
Authors: Berg-Brown Nancy N. , Gronski Matthew A. , Jones Russell G. , Elford Alisha R. , Deenick Elissa K. , Odermatt Bernhard , Littman Dan R. , Ohashi Pamela S.
Published: March 2004

Understanding the pathways that signal T cell tolerance versus activation is key to regulating immunity. Previous studies have linked CD28 and protein kinase C-θ (PKCθ) as a potential signaling pathway that influences T cell activation. Therefore, we have compared the responses of T cells deficient for CD28 and PKCθ in vivo and in vitro. Here, we demonstrate that the absence of PKCθ leads to the induction of T cell anergy, with a phenotype that is comparable to the absence of CD28. Further experiments examined whether PKCθ triggered other CD28-dependent responses. Our data show that CD4 T cell–B cell cooperation is dependent on CD28 but not PKCθ, whereas CD28 costimulatory signals that augment proliferation can be uncoupled from signals that regulate anergy. Therefore, PKCθ relays a defined subset of CD28 signals during T cell activation and is critical for the induction of activation versus tolerance in vivo.
A B Cell Receptor with Two Igα Cytoplasmic Domains Supports Development of Mature But Anergic B Cells
Authors: Reichlin Amy , Gazumyan Anna , Nagaoka Hitoshi , Kirsch Kathrin H. , Kraus Manfred , Rajewsky Klaus , Nussenzweig Michel C.
Published: March 2004

B cell receptor (BCR) signaling is mediated through immunoglobulin (Ig)α and Igβ a membrane-bound heterodimer. Igα and Igβ are redundant in their ability to support early B cell development, but their roles in mature B cells have not been defined. To examine the function of Igα–Igβ in mature B cells in vivo we exchanged the cytoplasmic domain of Igα for the cytoplasmic domain of Igβ by gene targeting (Igβc→αc mice). Igβc→αc B cells had lower levels of surface IgM and higher levels of BCR internalization than wild-type B cells. The mutant B cells were able to complete all stages of development and were long lived, but failed to differentiate into B1a cells. In addition, Igβc→αc B cells showed decreased proliferative and Ca2+ responses to BCR stimulation in vitro, and were anergic to T-independent and -dependent antigens in vivo.
Immunoprevention of Basal Cell Carcinomas with Recombinant Hedgehog-interacting Protein
Authors: Vogt Annika , Chuang Pao-Tien , Hebert Jennifer , Hwang Jimmy , Lu Ying , Kopelovich Levy , Athar Mohammad , Bickers David R. , Epstein Ervin H.
Published: March 2004

Basal cell carcinomas (BCCs) are driven by abnormal hedgehog signaling and highly overexpress several hedgehog target genes. We report here our use of one of these target genes, hedgehog-interacting protein (Hip1), as a tumor-associated antigen for immunoprevention of BCCs in Ptch1+/− mice treated with ionizing radiation. Hip1 mRNA is expressed in adult mouse tissues at levels considerably lower than those in BCCs. Immunization with either of two large recombinant Hip1 polypeptides was well tolerated in Ptch1+/− mice, induced B and T cell responses detectable by enzyme-linked immunosorbent assay, Western blot, delayed type hypersensitivity, and enzyme-linked immunospot assay, and reduced the number of BCCs by 42% (P < 0.001) and 32% (P < 0.01), respectively. We conclude that immunization with proteins specifically up-regulated by hedgehog signaling may hold promise as a preventive option for patients such as those with the basal cell nevus syndrome who are destined to develop large numbers of BCCs.
Sclerostin Is an Osteocyte-expressed Negative Regulator of Bone Formation, But Not a Classical BMP Antagonist
Authors: van Bezooijen Rutger L. , Roelen Bernard A.J. , Visser Annemieke , van der Wee-Pals Lianne , de Wilt Edwin , Karperien Marcel , Hamersma Herman , Papapoulos Socrates E. , ten Dijke Peter , Löwik Clemens W.G.M.
Published: March 2004

Sclerosteosis, a skeletal disorder characterized by high bone mass due to increased osteoblast activity, is caused by loss of the SOST gene product, sclerostin. The localization in bone and the mechanism of action of sclerostin are not yet known, but it has been hypothesized that it may act as a bone morphogenetic protein (BMP) antagonist. We show here that SOST/sclerostin is expressed exclusively by osteocytes in mouse and human bone and inhibits the differentiation and mineralization of murine preosteoblastic cells (KS483). Although sclerostin shares some of the actions of the BMP antagonist noggin, we show here that it also has actions distinctly different from it. In contrast to noggin, sclerostin did not inhibit basal alkaline phosphatase (ALP) activity in KS483 cells, nor did it antagonize BMP-stimulated ALP activity in mouse C2C12 cells. In addition, sclerostin had no effect on BMP-stimulated Smad phosphorylation and direct transcriptional activation of MSX-2 and BMP response element reporter constructs in KS483 cells. Its unique localization and action on osteoblasts suggest that sclerostin may be the previously proposed osteocyte-derived factor that is transported to osteoblasts at the bone surface and inhibits bone formation.
Critical Role for Kit-mediated Src Kinase But Not PI 3-Kinase Signaling in Pro T and Pro B Cell Development
Authors: Agosti Valter , Corbacioglu Selim , Ehlers Imke , Waskow Claudia , Sommer Gunhild , Berrozpe Georgina , Kissel Holger , Tucker Christine M. , Manova Katia , Moore Malcolm A.S. , Rodewald Hans-Reimer , Besmer Peter
Published: March 2004

The Kit receptor functions in hematopoiesis, lymphocyte development, gastrointestinal tract motility, melanogenesis, and gametogenesis. To investigate the roles of different Kit signaling pathways in vivo, we have generated knock-in mice in which docking sites for PI 3-kinase (KitY719) or Src kinase (KitY567) have been mutated. Whereas steady-state hematopoiesis is normal in KitY719F/Y719F and KitY567F/Y567F mice, lymphopoiesis is affected differentially. The KitY567F mutation, but not the KitY719F mutation, blocks pro T cell and pro B cell development in an age-dependent manner. Thus, the Src family kinase, but not the PI 3-kinase docking site in Kit, mediates a critical signal for lymphocyte development. In agreement with these results, treatment of normal mice with the Kit tyrosine kinase inhibitor imatinib (Gleevec®) leads to deficits in pro T and pro B cell development, similar to those seen in KitY567F/Y567F and KitW/W mice. The two mutations do not affect embryonic gametogenesis but the KitY719F mutation blocks spermatogenesis at the spermatogonial stages and in contrast the KitY567F mutation does not affect this process. Therefore, Kit-mediated PI 3-kinase signaling and Src kinase family signaling is highly specific for different cellular contexts in vivo.
Influence of Permeant Ions on Voltage Sensor Function in the Kv2.1 Potassium Channel
Authors: Consiglio Joseph F. , Korn Stephen J.
Published: March 2004

We previously demonstrated that the outer vestibule of activated Kv2.1 potassium channels can be in one of two conformations, and that K+occupancy of a specific selectivity filter site determines which conformation the outer vestibule is in. These different outer vestibule conformations result in different sensitivities to internal and external TEA, different inactivation rates, and different macroscopic conductances. The [K+]-dependent switch in outer vestibule conformation is also associated with a change in rate of channel activation. In this paper, we examined the mechanism by which changes in [K+] modulate the rate of channel activation. Elevation of symmetrical [K+] or [Rb+] from 0 to 3 mM doubled the rate of on-gating charge movement (Qon), measured at 0 mV. Cs+produced an identical effect, but required 40-fold higher concentrations. All three permeant ions occupied the selectivity filter over the 0.03–3 mM range, so simple occupancy of the selectivity filter was not sufficient to produce the change in Qon. However, for each of these permeant ions, the speeding of Qonoccurred with the same concentration dependence as the switch between outer vestibule conformations. Neutralization of an amino acid (K356) in the outer vestibule, which abolishes the modulation of channel pharmacology and ionic currents by the K+-dependent reorientation of the outer vestibule, also abolished the K+-dependence of Qon. Together, the data indicate that the K+-dependent reorientation in the outer vestibule was responsible for the change in Qon. Moreover, similar [K+]-dependence and effects of mutagenesis indicate that the K+-dependent change in rate of Qoncan account for the modulation of ionic current activation rate. Simple kinetic analysis suggested that K+reduced an energy barrier for voltage sensor movement. These results provide strong evidence for a direct functional interaction, which is modulated by permeant ions acting at the selectivity filter, between the outer vestibule of the Kv2.1 potassium channel and the voltage sensor.
Tenacibaculum skagerrakense sp. nov., a marine bacterium isolated from the pelagic zone in Skagerrak, Denmark
Authors: Frette Lone , Jørgensen Niels O. G. , Irming Heidi , Kroer Niels
Published: March 2004

A number of bacteria were isolated from sea water in Skagerrak, Denmark, at 30 m depth. Two of the isolates, strains D28 and D30T, belonged to the Flavobacteriaceae within the Cytophaga–Flavobacterium–Bacteroides group. Sequencing of 16S rRNA genes of the two strains indicated strongly that they belonged to the genus Tenacibaculum and that they showed greatest similarity to the species Tenacibaculum amylolyticum and Tenacibaculum mesophilum. DNA–DNA hybridization values, DNA base composition and phenotypic characteristics separated the Skagerrak strains from the other species within Tenacibaculum. Thus, it is concluded that the strains belong to a novel species within the genus Tenacibaculum, for which the name Tenacibaculum skagerrakense sp. nov. is proposed, with strain D30T (=ATCC BAA-458T=DSM 14836T) as the type strain.
Ancylobacter rudongensis sp. nov., isolated from roots of Spartina anglica
Authors: Xin Yu Hua , Zhou Yu Guang , Zhou Hui Ling , Chen Wen Xin
Published: March 2004

A curved, ring-like bacterium, strain AS 1.1761T, isolated from the roots of Spartina anglica, was studied by a polyphasic approach. According to phylogenetic analysis, strain AS 1.1761T belongs to the genus Ancylobacter, with 99·21 % 16S rDNA sequence similarity to Ancylobacter aquaticus, the only species described so far in this genus. However, strain AS 1.1761T had no significant DNA–DNA binding with the type strain of A. aquaticus. In addition, strain AS 1.1761T differed from A. aquaticus in many phenotypic features. Based on molecular and phenotypic data, a novel species, Ancylobacter rudongensis sp. nov., is proposed. The type strain is AS 1.1761T (=JCM 11671T).
Anaerotruncus colihominis gen. nov., sp. nov., from human faeces
Authors: Lawson Paul A. , Song Yuli , Liu Chengxu , Molitoris Denise R. , Vaisanen Marja-Liisa , Collins Matthew D. , Finegold Sydney M.
Published: March 2004

Phenotypic and phylogenetic studies were performed on two isolates of an unidentified Gram-positive, anaerobic, non-spore-forming, rod-shaped bacterium that was isolated from human faeces. The organisms were catalase-negative, produced acetic and butyric acids as end products of metabolism and possessed a DNA G+C content of approximately 54 mol%. Comparative 16S rRNA gene sequencing demonstrated that the two isolates were related closely to each other and formed a hitherto unknown sublineage within theClostridium leptumrRNA cluster of organisms. Based on phylogenetic and phenotypic evidence, it is proposed that the unknown bacterium should be classified in a novel genus asAnaerotruncus colihominisgen. nov., sp. nov. The type strain ofAnaerotruncus colihominisis WAL 14565T=CCUG 45055T=CIP 107754T.
Sulfitobacter delicatus sp. nov. and Sulfitobacter dubius sp. nov., respectively from a starfish (Stellaster equestris) and sea grass (Zostera marina)
Authors: Ivanova Elena P. , Gorshkova Nataliya M. , Sawabe Tomoo , Zhukova Natalia V. , Hayashi Karin , Kurilenko Valerie V. , Alexeeva Yulia , Buljan Vlado , Nicolau Dan V. , Mikhailov Valery V. , Christen Richard
Published: March 2004

On the basis of data from phenotypic and genotypic characterization and analysis of 16S rRNA gene sequences, two novel species belonging to the genus Sulfitobacter are described. Strains KMM 3584T, a pale-yellowish, non-motile strain isolated from a starfish (Stellaster equestris), and KMM 3554T, which is motile by means of a single subpolar flagellum and was isolated from sea grass (Zostera marina), are marine, Gram-negative, aerobic, rod-shaped organisms. Both strains have the ability to degrade gelatin, but not casein, chitin, agar, DNA, Tween 80 or starch. Strain KMM 3584T decomposed alginate and grew at NaCl concentrations of 1–8 % and temperatures of 12–37°C, whereas strain KMM 3554T grew in 1–12% NaCl and at temperatures of 10–30°C. The predominant fatty acid was 18:1ω7, amounting to up to 80% of the total fatty acids. The other characteristic feature was the presence of 18:2 isomers. The DNA G+C contents of KMM 3584T and KMM 3554T were respectively 60·0 and 63·7 mol%. The level of DNA similarity between the two strains was 33%. DNA from KMM 3584T and KMM 3554T had hybridization values of 5–24% and 10–41%, respectively, with DNA from the type strains of Sulfitobacter pontiacus, Sulfitobacter brevis, Sulfitobacter mediterraneus and Staleya guttiformis. It is proposed that strains KMM 3584T (=LMG 20554T=ATCC BAA-321T) and KMM 3554T (=LMG 20555T=ATCC BAA-320T) represent two novel species, Sulfitobacter delicatus sp. nov. and Sulfitobacter dubius sp. nov., respectively.
Bacillus shackletonii sp. nov., from volcanic soil on Candlemas Island, South Sandwich archipelago
Authors: Logan Niall A. , Lebbe Liesbeth , Verhelst An , Goris Johan , Forsyth Gillian , Rodríguez-Díaz Marina , Heyndrickx Marc , De Vos Paul
Published: March 2004

A sample of mossy soil taken from the eastern lava flow of northern Candlemas Island, South Sandwich archipelago, yielded six isolates of aerobic, endospore-forming bacteria. Miniaturized routine phenotypic tests and other observations, amplified rDNA restriction analysis and SDS-PAGE analysis suggested that the strains represent a novel taxon. 16S rDNA sequence comparisons support the proposal of a novel species, Bacillus shackletonii sp. nov., the type strain of which is LMG 18435T (=CIP 107762T).
Amycolatopsis palatopharyngis sp. nov., a potentially pathogenic actinomycete isolated from a human clinical source
Authors: Huang Ying , Paściak Mariola , Liu Zhiheng , Xie Qiong , Gamian Andrzej
Published: March 2004

The taxonomic position of an actinomycete, strain 1BDZT, isolated from a clinical human source was determined using a polyphasic approach. Phylogenetic analysis based on almost complete 16S rDNA sequences showed that this organism consistently formed a distinct line with theAmycolatopsis methanolicasubclade within the genusAmycolatopsis, and shared moderately low 16S rDNA similarity (<96·5 %) with other species. The organism was also found to have chemical and morphological properties typical of members of the genusAmycolatopsis. A range of phenotypic characteristics readily distinguished this strain from representatives of all species ofAmycolatopsiswith validly published names. On the basis of these data, a novel species,Amycolatopsis palatopharyngissp. nov., is proposed to accommodate strain 1BDZT(=AS 4.1729T=PCM 2600T).