bluuebunny/crossref_metadata_2025 huggingface dataset:
A polymorphic CD40 ligand (CD154) molecule mediates CD40‐dependent signalling but interferes with the ability of soluble CD40 to functionally block CD154 : CD40 interactions
Authors: Barnhart B. , Ford G. S. , Bhushan A. , Song C. , Covey L. R.
Published: March 2003

We report the characterization of a naturally occurring polymorphism in CD40 ligand (CD40L, CD154) expressed by activated T cells from a young female patient. This polymorphism encodes a nonconservative Gly → Arg substitution in amino acid 219 in the extracellular, CD40 binding domain of the molecule. Studies carried out with 293 epithelial cells ectopically expressing the polymorphic protein (CD154/G219R) revealed reduced levels of binding to different anti‐CD154 monoclonal antibodies (mAb) and CD40‐immunoglobulin (CD40‐Ig). However, recognition of the polymorphic and wild‐type CD154 molecules by a polyclonal antiserum was comparable, suggesting that the polymorphism affects the ability of the protein to interact with CD40 but does not significantly alter its surface expression. To determine if reduced cross‐linking of CD40 mediated decreased functional effects, three CD40‐dependent properties were measured. We found that pathways leading to the induction of surface CD23, CD80, and Iγ transcription were activated in response to CD154/G219R signalling. However, the decrease in affinity for CD40 by the mutated CD154 affected the ability of CD40‐Ig to efficiently interfere with the binding and effectively block induced CD80 expression. In contrast, we found that the 5c8 mAb, which recognized the polymorphic molecule to a similar extent as wild‐type CD154, effectively blocked the interaction between CD154/G219R and CD40 as measured by CD80 expression. These findings suggest that naturally occurring polymorphisms in the CD154 molecule may affect the ability of CD40‐mediated functions to be blocked by soluble CD40 or anti‐CD154 mAb in the therapeutic treatment of disease and graft rejection.
Increasing the frequency of T‐cell precursors specific for a cryptic epitope of hen‐egg lysozyme converts it to an immunodominant epitope
Authors: Thatcher T. H. , O'brien D. P. , Altuwaijri S. , Barth R. K.
Published: March 2003

Efforts to understand the mechanisms that govern how immunodominant T‐cell epitopes are selected from protein antigens have focused mostly on differences in the efficiency of processing and presentation of peptide/major histocompatibility complex (MHC) complexes by antigen‐presenting cells, while little attention has been directed at the role of the T‐cell repertoire. In this report, the influence of the T‐cell repertoire on immunodominance was investigated using transgenic mice that express the β chain from a T‐cell receptor specific for a cryptic Ek restricted epitope of hen‐egg lysozyme, HEL85‐96. In these mice, the frequency of HEL85‐96‐specific T‐cell precursors is increased 10–20‐fold over non‐transgenic mice. Transgenic mice respond as well as non‐transgenic controls to intact HEL, even though they respond poorly or not at all to a variety of other antigens, including the dominant H‐2k restricted epitopes of HEL. Following immunization with native HEL, the only HEL peptide that could recall a response in vitro in the transgenic mice was HEL85‐96. Therefore, this normally cryptic epitope is the sole immunodominant epitope in the transgenic mice, and this alteration in immune response is due solely to an increase in the frequency of specific T‐cell precursors. An analysis of four additional H‐2k restricted cryptic epitopes of HEL suggests that three are similarly limited by T‐cell frequency, and that only one is consistent with a defect in efficient antigen presentation. This indicates that there are at least two different types of cryptic epitopes, one in which crypticity is caused by inefficient processing or presentation, and another in which the frequency of specific T‐cell progenitors is limiting.
The route of administration of an immunodominant peptide derived from heat‐shock protein 65 dramatically affects disease outcome in pristane‐induced arthritis
Authors: Francis J. N. , Lamont A. G. , Thompson S. J.
Published: March 2003

Previous studies have shown that immunization of mice with an immunodominant epitope from heat‐shock protein 65 (hsp 65) (amino acids 261–271) can protect from the development of pristane‐induced arthritis (PIA) and this protection is mediated by an antigen‐specific T helper type 2 (Th2) cytokine response. Here we confirm these findings and show that frequent intranasal administration of this peptide exacerbates disease. In naive mice given peptide intranasally an antigen‐specific T‐cell population is systemically activated similar to that induced by peptide immunization in incomplete Freund’s adjuvant. Thus, a paradox exists whereby apparently similar peptide‐specific populations are either associated with protection from, or exacerbation of, PIA. However, comparison of cytokine profiles reveals differences between these two cell populations. Peptide inhalation induces the production of Th1‐type cytokines (interferon‐γ) whereas intraperitoneal immunization leads to the production of Th2‐type cytokines (interleukin‐4, interleukin‐5 and interleukin‐10) by splenic T cells upon stimulation with peptide. Thus, for the application of nasal ‘tolerance’ in clinical medicine, it is important to identify antigens and dosing regimes that counteract but do not activate adverse immune responses.
Mice lacking tartrate‐resistant acid phosphatase (Acp 5) have disordered macrophage inflammatory responses and reduced clearance of the pathogen, Staphylococcus aureus
Authors: Bune A. J. , Hayman A. R. , Evans M. J. , Cox T. M.
Published: March 2003

Tartrate‐resistant acid phosphatase (TRAP) is a lysosomal di‐iron protein of mononuclear phagocytes and osteoclasts. Hitherto, no role for the enzyme in immunity has been identified; however, knockout mice lacking TRAP have a skeletal phenotype caused by an intrinsic osteoclast defect. To investigate a putative function for TRAP in macrophages (Mφ), we investigated proinflammatory responses and systemic microbial clearance in knockout mice compared with age‐ and gender‐matched congenic wild‐type mice. Phorbol 12‐myristate 13‐acetate (PMA)‐stimulated and interferon‐γ (IFN‐γ)‐induced superoxide formation was enhanced in peritoneal Mφ lacking TRAP; nitrite production in response to stimulation with lipopolysaccharide (LPS) and IFN‐γ was also increased. In addition, secretion of the proinflammatory cytokines, tumour necrosis factor‐α (TNF‐α), interleukin (IL)‐1β and IL‐12, was significantly greater in TRAP‐deficient Mφ when stimulated with LPS, with or without addition of either TNF‐α or IFN‐γ. The activity of tartrate‐sensitive (lysosomal) acid phosphatase was increased in Mφ from the knockout mice but activities of the lysosomal hydrolases N‐acetyl β‐glucosaminidase and acid β‐glucuronidase were unchanged, indicating selective activation of compensatory acid phosphatase activity. Evidence of impaired Mφ function in vivo was obtained in TRAP knockout mice, which showed delayed clearance of the microbial pathogen, Staphylococcus aureus, after sublethal intraperitoneal inoculation. After microbial challenge, peritoneal exudates obtained from TRAP knockout mice had a reduced population of Mφ. As peritoneal Mφ and neutrophils lacking TRAP were able to phagocytose and kill S. aureus normally in vitro, TRAP may directly or indirectly influence recruitment of Mφ to sites of microbial invasion. Our study shows that TRAP participates in the inflammatory response of the Mφ and influences effector signalling pathways in innate immunity.
Reduced herpes simplex virus type 1 latency in Flt‐3 ligand‐treated mice is associated with enhanced numbers of natural killer and dendritic cells
Authors: Smith J. R. , Thackray A. M. , Bujdoso R.
Published: March 2003

We have investigated the effect of Flt‐3 ligand (Flt‐3L) on the resistance to herpes simplex virus type‐1 (HSV‐1) infection in BALB/c mice which are normally highly susceptible to challenge with this virus. We have confirmed data by others that in vivo treatment with Flt‐3L causes an increase in dendritic cells (DC) and natural killer (NK) cells in lymphoid tissue. Increasing doses of Flt‐3L caused a corresponding increase in liver and spleen CD11c+ DC which were increased up to 20‐fold compared with control levels. A significant expansion of NK cells was seen in the spleen of Flt‐3L‐treated mice where the number of DX5+ cells was increased by up to fivefold. We subsequently tested the hypothesis that Flt‐3L treatment, at the time of viral infection, might lead to enhanced immunity and protection against viral pathogenesis. Two murine models of HSV‐1 (SC16) infection were used. In the first model, mice were injected with Flt‐3L daily for 9 days. Control mice received mouse serum albumin (MSA). On day 7 of the Flt‐3L treatment 106 plaque‐forming units (PFU) of SC16 was inoculated into the ear pinna. Flt‐3L treatment significantly reduced mortality following virus inoculation, with 80% survivors in this group compared with 20% survivors in the MSA‐treated group. In the second model, Flt‐3L‐treated mice were scarified with 104 PFU of SC16. In this case there was 60% survival in the Flt‐3L‐treated group of mice compared with 10% survival in the MSA‐treated group. Assessment by in situ hybridization for latency‐associated transcripts showed that Flt‐3L treatment reduced the amount of latent virus within infected neurons. These studies show that in vivo treatment with Flt‐3L results in protection against challenge with live HSV‐1, which may be a consequence of enhanced numbers of DC and/or NK.
Mechanisms of interleukin‐10‐mediated immune suppression
Authors: Akdis Cezmi A. , Blaser Kurt
Published: March 2003

Specific immune suppression and induction of anergy are essential processes in the regulation and circumvention of immune defence. Interleukin‐10 (IL‐10), a suppressor cytokine of T‐cell proliferative and cytokine responses, plays a key regulatory role in tolerizing exogenous antigens during specific immunotherapy (SIT) of allergy and natural exposure to antigens. Specific T‐cell tolerance is directed against the T‐cell epitopes of an antigen and characterized by suppressed proliferative and T helper type 1 (Th1) and type 2 (Th2) cytokine responses. IL‐10 elicits tolerance in T cells by selective inhibition of the CD28 co‐stimulatory pathway and thereby controls suppression and development of antigen‐specific immunity. IL‐10 only inhibits T cells stimulated by low numbers of triggered T‐cell receptors and which therefore depend on CD28 co‐stimulation. T cells receiving a strong signal from the T‐cell receptor alone, and thus not requiring CD28 co‐stimulation, are not affected by IL‐10. IL‐10 inhibits CD28 tyrosine phosphorylation, the initial step of the CD28 signalling pathway, and consequently the phosphatidylinositol 3‐kinase p85 binding to CD28. Together these results demonstrate that IL‐10‐induced selective inhibition of the CD28 co‐stimulatory pathway acts as a decisive mechanism in determining whether a T cell will contribute to an immune response or become anergic.
The role of donor T cells for target organ injuries in acute and chronic graft‐versus‐host disease
Authors: Kataoka Yasuro , Iwasaki Tsuyoshi , Kuroiwa Takanori , Seto Yoshifumi , Iwata Nobuo , Hashimoto Naoaki , Ogata Atsushi , Hamano Teruaki , Kakishita Eizo
Published: March 2003

Donor T cells are crucial for target organ injury in graft‐versus‐host disease (GVHD). We examined the effects of donor T cells on the target organs using a parent‐into‐F1 model of acute and chronic GVHD. Donor T cells showed engraftment in the spleen, small intestine and liver of mice with acute GVHD, causing typical GVHD pathology in these organs. Interferon‐γ and Fas ligand expression were up‐regulated, and host lymphocytes were depleted in the target organs of these mice. In contrast, donor T cells did not show engraftment in the small intestine of mice with chronic GVHD, and no GVHD pathology was observed in this organ. However, both donor T‐cell engraftment and GVHD pathology were observed in the spleen and liver of chronic GVHD mice, along with the up‐regulation of interleukin‐4 (IL‐4) and IL‐10 expression plus the expansion of host lymphocytes such as splenic B cells and hepatic natural killer (NK) 1.1+ T cells. Donor anti‐host cytotoxic T‐lymphocyte activity was observed in spleen cells from mice with acute GVHD, but not in spleen cells from mice with chronic GVHD. Transplantation of Fas ligand‐deficient (gld) spleen cells did not induce host lymphocyte depletion in target organs. These results indicate that donor T cells augment type 1 T helper immune responses and deplete the host lymphocytes from target organs mainly by Fas‐mediated pathways in acute GVHD, while donor T cells augment type 2 T helper immune responses and expand host splenic B cells and hepatic NK1.1+ T cells in chronic GVHD.
Lack of evidence for aggregation‐dependent enhancement of p56lck in the signal transduction upon major histocompatibility complex recognition by mature T cells
Authors: Eshima Koji , Suzuki Harumi , Shinohara Nobukata
Published: March 2003

The kinase activity of lymphocyte‐specific tyrosine kinase p56lck (Lck) upon physiological major histocompatibility complex (MHC) recognition by normal mature T cells was examined. Recognition of the target MHC molecules by T cells induced phosphorylation of the ζ‐chain without obvious enhancement of the background Lck activity. There was no sign of enhancement of Lck through putative T‐cell receptor (TCR)‐independent class II MHC/CD4 interactions either. As has been reported, cross‐linking of CD4 molecules by antibodies induced a marked enhancement of Lck activity. However, it did not have an immediate relevance to TCR‐mediated signal transduction, as judged from the lack of detectable de novo phosphorylation of ζ‐chain and the absence of functional responses of T cells. These results strongly favour the model in which TCR‐mediated signal transduction does not involve aggregation‐dependent enhancement of Lck, suggesting that the signal can be triggered simply by the recruitment of already active Lck with basal kinase activity through the formation of a TCR/MHC/CD4 ternary complex.
Differential expansion of T‐cell receptor variable beta subsets after antigenic stimulation in patients with different outcomes of hepatitis C infection
Authors: Woitas Rainer P. , Sippel Martin , Althausen Eva‐Maria , Brackmann Hans H. , Kochan Bettina , Matz Bertfried , Rockstroh Jürgen K. , Sauerbruch Tilman , Spengler Ulrich
Published: March 2003

Persistent antigenic stimulation during chronic hepatitis C may alter the T‐cell receptor variable chain beta (TCR BV) repertoire as well as the cytokine responses of hepatitis C virus (HCV)‐specific T lymphocytes. We analysed the distribution of the TCR BV subsets 2.1, 3.1, 5.1, 6.1, 8, 13.1, 13.6, 14.1, 17.1, 21.3 in relation to intracytoplasmic expression of interleukin‐2, interferon‐γ, interleukin‐4 and interleukin‐10. Using flow cytometry, CD45RO+ memory T cells of 27 patients with chronic hepatitis C, eight patients with resolved HCV infection and 16 non‐HCV‐related controls were studied with and without stimulation by the HCV core, NS3, NS4, NS5a and NS5b proteins. Patients with chronic and resolved hepatitis C differed by larger basal TCR BV2.1+, BV6.1+, BV17.1+ and BV21.3+ subsets in chronic hepatitis C, which were correlated to the numbers of T cells with spontaneous interleukin‐2 and interferon‐γ production (r=0·51–0·73, P<0·05). Upon HCV‐specific stimulation these subsets did not expand, whereas a marked in vitro expansion of TCR BV8+ T cells in response to all HCV proteins was selectively noted in chronic hepatitis C (P<0·05). This expansion of TCR BV8+ memory T cells was significantly correlated to HCV‐induced interleukin‐10 expression (r=0·58–0·98, P<0·01). Thus, differential involvement of selected TCR BV subsets may be related to the outcome of HCV infection.
In vivo tolerance breakdown with dendritic cells pulsed with U1A protein in non‐autoimmune mice: the induction of a high level of autoantibodies but not renal pathological changes
Authors: Suen Jau‐Ling , Chuang Ya‐Hui , Chiang Bor‐Luen
Published: March 2003

One of the hallmarks of systemic autoimmune diseases, such as systemic lupus erythematosus (SLE), is the immune response to nuclear autoantigens. Several studies have proposed that dendritic cells may acquire the nuclear autoantigens from the apoptotic cells to initiate the systemic autoimmune responses. To examine the immune response to a nuclear autoantigen induced by dendritic cells, bone marrow‐derived dendritic cells (BMDCs) pulsed with U1 small nuclear ribonucleoprotein (snRNP)‐A protein (U1A) were intravenously injected into non‐autoimmune mice. The results showed that BMDCs pulsed with U1A proteins by intravenous injection into BALB/c (H‐2d) and DBA‐2×NZW F1 (H‐2d/u) mice were capable of activating the autoreactive T cells and inducing a high titre of immunoglobulin G (IgG) anti‐U1A antibodies. Both groups of mice with a high anti‐U1A autoantibody titre also transiently developed IgG against double‐stranded (ds) DNA. However, unlike NZB×NZW F1 (BWF1) (H‐2d/u) mice, no obviously histopathological changes to the glomeruli were noted in the mice treated either with BMDCs or with U1A‐pulsed BMDCs. Several months after immunization, all mice treated with U1A‐pulsed BMDCs did develop IgG, but not the complement C3 deposit in the glomeruli. The cytokine profile produced by the U1A‐specific T cells of primed DBA‐2×NZW F1 mice was skewed toward the T helper type 1 phenotype compared with that of BWF1 mice. The model we describe here adds to the further understanding of the pathogenic mechanisms, such as self‐antigen shifting, and the mechanisms that account for the different responses to self‐antigens when in a normal or an autoimmune state.
Augmented expression of tumour necrosis factor‐α induced by lipopolysaccharide in spleen of human monocyte chemoattractant protein‐1 transgenic mouse enhances the lipopolysaccharide sensitivity of the marginal zone macrophages
Authors: Ato Manabu , Iwabuchi Kazuya , Shimada Shigeki , Mukaida Naofumi , Onoé Kazunori
Published: March 2003

Monocyte chemoattractant protein‐1 (MCP‐1) is a protective cytokine in murine endotoxaemia induced by lipopolysaccharide (LPS). In this study, LPS‐induced pathophysiology in the human (h) MCP‐1 transgenic mouse (Tgm) line was investigated. The hMCP‐1 Tgm showed a marked increase in the mortality and weight loss following LPS administration. In the Tgm spleens, disappearance of marginal zone macrophages (MZMφ) and dendritic cells (DC) was induced by a smaller amount of LPS than that required for the disappearance in non‐transgenic littermates. A significant number of apoptotic cells were seen in these areas. Furthermore, expressions of tumour necrosis factor‐α (TNF‐α), interleukin‐1α (IL‐1α), and IL‐6 mRNA were enhanced and sustained in the LPS‐treated Tgm. Neutralization of TNF‐α considerably depressed the LPS‐sensitivity of Tgm. These findings demonstrate that the continuous and systemic presence of MCP‐1 is no more protective toward endotoxaemia and suggest that the high sensitivity of the MZMφ and DC to LPS is attributed to the enhanced TNF‐α production in the hMCP‐1 Tgm.
Maternal and newborn immunization with a human immunodeficiency virus‐1 immunogen in a rodent model
Authors: Moss Ronald B. , Savary Jay R. , Diveley Jocelyn P. , Jensen Fred , Carlo Dennis J.
Published: March 2003

We examined immunization with an inactivated, gp120‐depleted human immunodeficiency virus (HIV) antigen in incomplete Freund's adjuvant (IFA), also containing a sequence of immunostimulatory (ISS) DNA, during the last trimester of pregnancy and neonatally in a rat model. Pregnant rats were immunized in the third trimester and their litters were immunized during the newborn period. In addition, litters of rats from non‐immunized mothers were immunized during the neonatal period. As another control, pregnant rats were immunized and their litters analysed. Supernants from peripheral blood mononuclear cells (PBMCs) were assayed from newborns at 4 weeks of age for HIV‐specific interferon‐γ (IFN‐γ), HIV‐specific regulated on activation, normal, T‐cell expressed, and secreted (RANTES), and serum for p24 antigen‐specific immunoglobulin G (IgG) production. In the animals whose pregnant mothers were immunized and were also immunized during the neonatal period, we observed HIV‐specific IFN‐γ production and HIV‐specific RANTES production, but weak p24 IgG antibody production. Animals immunized only during the neonatal period developed the highest levels of HIV‐specific IFN‐γ production, but somewhat lower levels of HIV‐specific RANTES and p24 IgG antibody production. The group of animals whose mothers had received immunizations during the last trimester of pregnancy, but were not immunized during the neonatal period, developed the strongest p24 IgG antibody levels, but little or undetectable HIV‐specific IFN‐γ or RANTES production. Neonatal immunization resulted primarily in cell‐mediated immune responses, while animals born to mothers who were immunized during the last trimester had primarily an antibody‐mediated immune response. Immunization of pregnant animals followed by neonatal immunization resulted in a mixed cell‐mediated/antibody type profile in the neonatal animal. Future studies should provide insights into neonatal immunity and potential vaccine approaches to prevent neonatal infection and perinatal transmission.
Groupware support as a moderator of interdepartmental knowledge communication in process improvement groups: an action research study
Authors: Kock Ned , McQueen Robert J.
Published: March 2003

This paper presents a review of the organizational learning literature that points to process improvement (PI) groups as an appropriate too for organizational knowledge communication. Based on this review, the impact of support provided by a class of groupware systems, email conferencing (EC) on knowledge dissemination in organizations is examined in the context of PI groups. Data were collected through an action research project, in which the researcher facilitated seven PI groups in two organizations with the support of an EC system implemented with Novel/ Groupwise and using a group methodology for PI called MetaProi. The study suggests that, overall, EC support seems to have a positive impact on knowledge dissemination in organizations when used in combination with a group methodology for PI. EC support effects on PI groups can be summarized as: (a) a reduction in, first, the influence of distance and other physical obstacles to the participation of members from different departments in PI groups, and, second, in the disruption that group discussions are likely to cause for individual group members, particularly when these members are from different departments; (b) a reduction in interdepartmental conflict obstacles to the formation of PI groups; and (c) an increase or decrease in individual learning in PI groups, depending on the complexity of the issues being discussed and the clarity of electronic contributions by members. Organizational implications of these research findings are discussed.
A conceptual framework for understanding business processes and business process modelling
Authors: Melão Nuno , Pidd Michael
Published: March 2003

It is increasingly common to describe organizations as sets of business processes that can be analysed and improved by approaches such as business process modelling. Successful business process modelling relies on an adequate view of the nature of business processes, but there is a surprising divergence of opinion about the nature of these processes. This paper proposes a conceptual framework to organize different views of business processes under four headings. It also aims at providing an integrated discussion of the different streams of thought, their strengths and limitations, within business process modelling. It argues that the multifaceted nature of business processes calls for pluralistic and multidisciplinary modelling approaches.
Whose job is it anyway?: organizational information competencies for value creation
Authors: Peppard Joe , Lambert Rob , Edwards Chris
Published: March 2003

Abstract.Research highlights that most business managers continue to be dissatisfied with the value they perceive they are deriving from their organization's information systems investments. On examining the literature, the dominant perspective is that creating value through information systems is primarily the responsibility of the IS function. Accordingly, to address this chronic malaise, attention generally focuses on the IS function with proposed prescriptions ranging from re‐skilling the IS professional through re‐engineering the IS function to the ultimate sanction of outsourcing. This paper examines the problem of value creation from IS investments from an organizational as opposed to an IS functional perspective. Drawing on resource‐based theory, the paper argues that the effective deployment and exploitation of information should be viewed as a ‘strategic asset’. To leverage value from IS, the paper proposes that organizations must recognize and develop information competencies and that the elements of these competencies are distributed throughout the organization and not solely resident in the IS function. Through a multimethodological approach these information competencies are identified and described. The resultant competencies are then studied in an organizational context. The paper ends by drawing conclusions and articulating further research directions and opportunities
Effects of intra‐group conflict on packaged software development team performance
Authors: Sawyer Steve
Published: March 2003

Abstract. Data from 40 packaged software development teams are used to test a path model that relates three antecedents, the presence of intragroup conflict and the level of conflict management to software development team performance. Findings indicate that a combination of the team's characteristics, team member characteristics and existing levels of intragroup conflict accounts for nearly one‐half of the variance between the best and worst‐performing teams. Furthermore, the level of conflict management moderates the relationship between existing levels of intragroup conflict and performance. These results highlight both the complexity of the social processes of packaged software development and the value of this perspective for gaining insight on software development performance.
Cloning and analysis of cDNAs encoding the hypusine‐containing protein eIF5A of two lepidopteran insect species
Authors: Van Oers Monique M. , Van Marwijk Mireille , Kwa Marcel S. G. , Vlak Just M. , Thomas Adri A. M.
Published: March 2003

Eukaryotic initiation factor eIF5A is essential for cell viability and contains a characteristic post‐translational modification of a specific lysine residue into a hypusine. cDNAs with similarity to eIF5A sequences were derived from Spodoptera exigua and S. frugiperda cDNA libraries. The deduced amino acid sequences are identical for both species and predict a protein with a molecular mass of 17.5 kDa. The Drosophila melanogaster eIF5A cDNA sequence was retrieved from the Drosophila EST Project. The predicted protein is 80% similar to Spodoptera eIF5A. A single eIF5A gene copy is present in the S. frugiperda genome, which is transcribed into four different transcripts. Infection of S. frugiperda cells with a baculovirus resulted in a strong decline of all four transcripts already at 12 h after infection. In contrast, the eIF5A protein was fairly stable up to 48 h post infection.
Phylogeny of the arthropod endosymbiont Wolbachia based on the wsp gene
Authors: Van Meer M. M. M. , Witteveldt J. , Stouthamer R.
Published: March 2003

Bacteria of the genus Wolbachia (Rickettsiae) are widespread in arthropods and can induce cytoplasmic incompatibility (CI), thelytoky (T) or feminization (F) in their host. Recent research on the wsp gene of mainly CI inducing Wolbachia has shown that this gene evolves at a much faster rate than previously sequenced genes such as 16S or ftsZ. As a result this gene appears to be very useful in subdividing the Wolbachia and twelve groups have been distinguished to date. Here we extend the Wolbachia wsp data set with fifteen T‐Wolbachia, one F‐Wolbachia and three other CI‐Wolbachia strains. The results showed: (i) the addition of seven groups; (ii) no relation between host phenotype and Wolbachia phylogenetic position; and (iii) possible horizontal Wolbachia transfer between the moth Ephestia kuehniella and its parasitoid Trichogramma spp.
Molecular characterization of the amplified carboxylesterase gene associated with organophosphorus insecticide resistance in the brown planthopper, Nilaparvata lugens
Authors: Small Graham J. , Hemingway Janet
Published: March 2003

Widespread resistance to organophosphorus insecticides (OPs) in Nilaparvata lugens is associated with elevation of carboxylesterase activity. A cDNA encoding a carboxylesterase, Nl‐EST1, has been isolated from an OP‐resistant Sri Lankan strain of N. lugens. The full‐length cDNA codes for a 547‐amino acid protein with high homology to other esterases/lipases. Nl‐EST1 has an N‐terminal hydrophobic signal peptide sequence of 24 amino acids which suggests that the mature protein is secreted from cells expressing it. The nucleotide sequence of the homologue of Nl‐EST1 in an OP‐susceptible, low esterase Sri Lankan strain of N. lugens is identical to Nl‐EST1. Southern analysis of genomic DNA from the Sri Lankan OP‐resistant and susceptible strains suggests that Nl‐EST1 is amplified in the resistant strain. Therefore, resistance to OPs in the Sri Lankan strain is through amplification of a gene identical to that found in the susceptible strain.
cDNA cloning and transcript distribution of two different neuroparsin precursors in the desert locust, Schistocerca gregaria
Authors: Janssen T. , Claeys I. , Simonet G. , De Loof A. , Girardie J. , Broeck J. Vanden
Published: March 2003

Neuroparsins were originally identified in locust corpus cardiacum extracts as folliculostatic or ‘antigonadotropic’ neuropeptides. This paper presents the cloning of two different neuroparsin precursor cDNAs from the brain of the desert locust, Schistocerca gregaria. The first transcript encodes the precursor (Scg‐NPP1) of S. gregaria neuroparsin A and B, whereas the second codes for a novel neuroparsin‐related peptide precursor (Scg‐NPP2). Both precursors display significant sequence similarities with each other and with the Locusta migratoria neuroparsin (Lom‐NPP) and Aedes aegypti ovary ecdysteroidogenic hormone (Aea‐OEH1) precursors. Northern blot analysis revealed that these neuroparsin transcripts are present in larval and adult locust brains. Interestingly, the Scg‐NPP2 mRNA content proved to be strongly regulated during the reproductive cycle in both adult males and females.
Genetic structure of a greenhouse population of the spider miteTetranychus urticae: spatio‐temporal analysis with microsatellite markers
Authors: Navajas M. , Perrot‐Minnot M. J. , Lagnel J. , Migeon A. , Bourse T. , Cornuet J. M.
Published: March 2003

The genetic structure of a greenhouse population of the miteTetranychus urticaewas studied by the analysis of five microsatellite loci. Genetic variation was compared during a crop season between periods of population foundation and rapid population increase and was investigated in two consecutive years. The population displayed significant heterozygote deficiency at all the sampling periods. However, inbreeding tended to decrease with increasing density (FIScoefficient between 0.13 and 0.25). No significant genetic differentiation between samples was found either at a spatial scale within the greenhouse or at a temporal scale between two growing seasons (FSTbetween 0.008 and 0.09). Estimations of the genetic relatedness between pairs of individuals indicated that the distances between pairs of sisters and unrelated mites in the greenhouse were not significantly different, suggesting that mites do not tend to form patches that reside close to the point of birth.
Isolation and molecular characterization of Musca domestica delta‐9 desaturase sequences
Authors: Eigenheer A. L. , Young S. , Blomquist G. J. , Borgeson C. E. , Tillman J. A. , Tittiger C.
Published: March 2003

We have isolated fatty acyl‐CoA desaturase cDNA (Mdomd9) and genomic sequences from the housefly, Musca domestica. Two ∼1.66 kb cDNAs were recovered. They had identical coding regions and 3′ untranslated regions (UTRs), but differed in their 5′ UTRs. The open reading frame encodes a 380 amino acid (aa) protein with 82% identity to Drosophila melanogaster desat1, and significant (> 50%) identity with other insect delta‐9 desaturases. Functional analyses in a yeast expression system confirmed the cDNA encodes a Δ9 desaturase. Northern analysis indicated two transcripts of 1.7 and 2.9 kb that hybridized specifically to the open reading frame. PCR amplification of genomic templates revealed three intron sites that are conserved among other insect species. Southern analysis of genomic DNA indicated at least two desaturase gene copies per haploid genome. There is a high degree of polymorphism, most of which appears to be due to variable intron sequences; curiously, individual flies had varying morphs of intron II and intron III. Together, the data suggest that there are more Δ9 desaturase alleles within the population studied than there are loci within the genome, and support other studies suggesting that insect fatty acyl‐CoA desaturases are a dynamically evolving gene family.
A comparison of digitally scanned radiographs with conventional film for the detection of small endodontic instruments
Authors: Fuge  , Stuck  , Love
Published: March 2003

The use of computers in dentistry is becoming common as a practice tool for a diverse number of tasks, including the storage and enhancement of intra‐oral radiographs. Several systems of digital radiography are available to produce a digital image including irradiation of a charged‐couple device and scanning conventional radiographs. This study compared various digital images of scanned periapical radiographs with the original radiographs to determine whether the digitized images offered any advantage when viewing small files at the radiographic apex. Twenty extracted permanent molar teeth were prepared by gaining straight line access to the root canals and a ISO size 06 K‐file was introduced into one of the canals until the tip was flush with the apical foramen. Using a standardized technique, radiographs were taken of the teeth using E‐speed film. The radiographs were scanned and five digital images: original, enhanced, negative to positive conversion, zoom and zoom of negative to positive were produced. Three evaluators compared each of the images with the radiograph for clarity of the endodontic file in relation to the radiographic apex. Results were analysed using the Wilcoxon signed rank test and the Kappa (κ) test was used to measure the level of agreement between the three evaluators. The results revealed that all the digital images produced by this scanner were inferior to the radiograph (P < 0.001) and that there was high agreement between evaluators.
Obturation of root canals with different sealers using non‐instrumentation technology
Authors: Lussi A. , Imwinkelried S. , Stich H.
Published: March 2003

Aim To evaluate and compare the. sealing quality of hand‐ or vacuum‐obturated root canals after hand preparation or hydrodynamic cleansing of root canals, respectively.

Methodology After assessing root curvature, 96 single‐rooted deep‐frozen teeth were divided into eight comparable groups. The root canals of four groups were instrumented with the balanced force technique. The remaining uninstrumented teeth were connected to a reduced‐pressure device (NIT) and the root‐canal system perfused with 2.5% NaOCl under alternating pressure fields. This dissolved the pulpal tissues and removed debris from the root‐canal system. The canals of the hand‐instrumented groups were obturated using the cold lateral condensation method with gutta‐percha and one of four different sealers (AH26, AH Plus, Apexit and Pulp Canal Sealer EWT). The teeth treated with the alternating pressure device (NIT) were obturated by a vacuum obturation method (NIT) with the same four sealers. The quality of the coronal seal was assessed using a dye penetration method. In order to minimize errors the roots were perfused with water before exposure to the dye, under vacuum. The teeth were then rendered transparent and the depth of penetration of the dye between the wall of the canal and the obturating material was measured with a stereomicroscope.

Results The canals cleaned and filled by NIT showed statistically significantly less dye penetration than those obturated by lateral condensation (P>0.05). Within the NIT group, Pulp Canal Sealer EWT exhibited significantly more dye penetration than Apexit. Amongst the control lateral condensation groups no significant differences were found between the various sealers.

Conclusions The present investigation demonstrated the validity of the NIT obturation method in combination with commonly used root‐canal sealers.
Endodontic management of a mandibular third molar fused with a fourth molar
Authors: Turell I. L. , Zmener O.
Published: March 2003

Case report Developmental anomalies in permanentmolars frequently require surgical intervention. A case of a mandibular third molar fused with a fourth molar which was successfully treated with conservative endodontic therapy is reported.
Response of periradicular tissues to growth factors introduced into the surgical site in the root‐end filling material
Authors: Regan J. D. , Gutmann J. L. , Iacopino A. M. , Diekwisch T.
Published: March 2003

Aim The objective of this study was to evaluate the healing of the periradicular tissues when exogenous growth factors were delivered to the respected root‐end. The healing response was compared with that when Diaket was used as a control.

Methodology Non‐surgical root canal treatment was performed on mandibular teeth in mongrel dogs. Surgical treatment followed and included root‐end resection and root‐end cavity preparation. Insulin‐like growth factor in combination with platelet‐derived growth factor, or fibroblast growth factor alone, were then placed in the root‐end preparations on a polylactic acid carrier (Atrisorb) with or without the incorporation of the carrier tetracalcium phosphate. The healingwas evaluated at 60 days with regard to presence of inflammatory response, bone regeneration, periodontal ligament formation and cementum formation.

Results Osseous regeneration in the excisional would and periodontal formation were significantly greater when Diaket was used as the root‐end filling material. Likewise, cementum deposition occurred significantly more frequently in the Diaket group (P0.05). The polylactic carrier Atrisorb remained in the surgical sites for the duration of the study.

Conclusions The use of specific growth factors, FGF and a combination of IGF/PDGF, delivered to the prepared root end in a collagen carrier did not initiate the desired periradicular tissue response of regeneration. Diaket, as used in this study, did stimulate a periradicular tissue response compatible with regeneration.
Effectiveness of 1 mol L−1 citric acid and 15% EDTA irrigation on smear layer removal
Authors: Di Lenarda R. , Cadenaro M. , Sbaizero O.
Published: March 2003

Di Lenarda R, Cadenaro M, Sbaizero O. Effectiveness of 1 mol L− 1 citric acid and 15% EDTA irrigation on smear layer removal. International Endodontic Journal, 33, 46–52, 2000.

Aim  The aim of this study was to evaluate in vitro the cleansing and smear layer removal capability of alternate canal irrigation with citric acid and NaOCl.

Methodology Eighty‐one teeth were divided into three groups on the basis of the type of instrumentation, namely, manual stainless steel, Ni‐Ti mechanized ProFile .04 taper or MACXim. The groups were further divided on the basis of irrigation protocol: 5% NaOCl alone, NaOCl alternated with 1 mol L−1 citric acid solution or a combination of 15% EDTA and Cetrimide solution. After longitudinal sectioning, dentinal walls were microphotographed with scanning electron microscopy at ×300 and ×1000 magnifications. Qualitative and quantitative cleansing level evaluations were performed using computerized image analysis software. Data were statistically evaluated using Kruskal–Wallis analysis and t‐test.

Results  Qualitative evaluation at ×300 and ×1000 showed no statistically significant differences in cleansing ability between citric acid, EDTA and NaOCl groups. Quantitative evaluation of smear layer removal, measured as open tubules/total dentinal surface ratio, showed that 1 mol L−1 citric acid solution was comparable to EDTA (11.97% vs. 10.36%) (NS); in samples treated with ProFile .04 taper instruments citric acid was most effective (16.17%), whilst in the group treated with manual instrumentation EDTA and Cetrimide were the most effective (11.94%). Specimens irrigated with 5% NaOCl demonstrated significantly more cleansing than those obtained in the other two groups (P <0.001).

Conclusions  1 mol L−1 citric acid solution was as effective in removing smear layer as EDTA, but was superior in specimens treated with ProFile .04 taper instruments.
Cleaning efficacy of a new root canal irrigation solution: a preliminary evaluation
Authors: Marais J. T.
Published: March 2003

Aim

A new product, electro‐chemically activated water, was compared to NaOCl for its cleaning effect on root canal walls.

Methodology

Root canal treatment was carried out on two groups of extracted teeth with one of the irrigants being used in each group. The control group received no treatment. All teeth were split and the canal walls viewed in a scanning electron microscope.

Results

The canal walls of the control group were covered by debris and bacteria. Sodium hypochlorite produced clean surfaces with the dentinal tubules open in some areas and occluded by the smear layer in other areas; in some areas bacteria were visible inside or under the smear layer. Electro‐chemically activated water produced markedly cleaner surfaces, removing the smear layer in large areas.

Conclusions

The cleaning efficacy of electro‐chemically activated water in root canals was considered to be superior to NaOCl.
Dimensional variability of nonstandardized greater taper finger spreaders with matching gutta‐percha points
Authors: Briseño Marroquín B. , Wolter D. , Willershausen‐Zönnchen B.
Published: March 2003

Aim

The purpose of this research was to determine the compatibility and dimensional variability between nonstandardized gutta‐percha points and matching finger spreaders.

Methodology

The diameters of nonstandardized gutta‐percha points (n = 15) and matching finger spreaders (n = 15) from different manufacturers (Kerr, Dentsply Maillefer, Vereignigte Dentalwerke and Roeko) were determined and statistically analysed using a profile projector under a magnification of 50 × (±0.002 mm).

Results

The dimensions of the finger spreaders and gutta‐percha cones were inconsistent. Of the 29 groups of nonstandardized gutta‐percha cones evaluated, 22 had standard deviations larger than 0.020 at D1. The standard deviations at D11 were greater than at D1, with the exception of those manufactured by Roeko. Overall, nonstandardized gutta‐percha cones made by VDW had the greatest dimensional consistency within each size group; the largest variations were seen in the Dentsply Maillefer gutta‐percha points. The 13 sizes of nonstandardized finger spreaders were more consistent.

Conclusions

The results of this study show that corresponding sizes of nonstandardized finger spreaders and gutta‐percha cones have statistically significant differences. There were large dimensional variations within sizes and discrepancies between the nominal size and actual size. Thus, these discrepancies may cause problems during root canal filling.
Influence of rotational speed, torque and operator’s proficiency on ProFile failures
Authors: Yared G. M. , Bou Dagher F. E. , Machtou P.
Published: March 2003

Aim

The purpose of this study was to evaluate the influence of rotational speed, torque, and operator experience with a specific Ni–Ti rotary instrumentation technique on the incidence of locking, deformation and separation of instruments.

Methodology

ProFile Ni–Ti rotary instruments (PRI) sizes 40–15 with a 6% taper were used in a crown‐down technique. In one group of canals (n = 300) speeds of 150, 250 and 350 rpm (subgroups 1, 2 and 3) were used. Each one of the subgroups included 100 canals. In a second group (n = 300) torque was set at 20, 30 and 55 Ncm (subgroups 4, 5 and 6). In the third group (n = 300) three operators with varying experience (subgroups 7, 8 and 9) were also compared. Each subgroup included the use of 10 sets of PRI and 100 canals of extracted human molars. Each set of PRI was used in up to 10 canals and then sterilized before each case. NaOCl 2.5% was used as an irrigant. The number of locked, deformed, and separated instruments for the different groups, and within each part of the study was analysed statistically for significance with chi‐squared tests.

Results

In group 1 only one instrument was deformed in the 150‐rpm group and no instruments separated or locked. In the 250‐rpm group instrument separation did not occur, however, a high incidence of locking, deformation and separation was noted in the 350‐rpm group. In general, instrument sizes 30–15 locked, deformed and separated. Chi‐squared statistics showed a significant difference between the 150 and 350 rpm groups but no difference between the 150 and 250 rpm groups with regard to instrument separation. Overall, there was a trend toward a higher incidence of instrument deformation and separation in smaller instruments. Locking and separation occurred during the final passage of the instruments, in the last (tenth) canal in each subgroup. In the second group, neither separation nor deformation and locking occurred during the use of the ProFile instruments, at 150 rpm, and at the different torque values. In the third group, chi‐squared analysis demonstrated that significantly more instruments separated with the least experienced operator. Instrument locking, deformation, and separation did not occur with the most experienced operator.

Conclusions

Preclinical training in the use of the PRI technique with crown‐down at 150 rpm were crucial in avoiding instrument separation and reducing the incidence of instrument locking and deformation.