bluuebunny/crossref_metadata_2025_split huggingface dataset:
Elevation of oleate‐activated phospholipase D activity during thymic atrophy
Authors: Lee Youngkyun , Song Soo‐Mee , Park Heung Soon , Kim Sungyeol , Koh Eun‐Hee , Choi Myung Sun , Choi Myung‐Un 
Published: March 2003

SummaryVarious phospholipases are thought to be associated with the in vitro apoptosis of thymocytes. In the present study, the in vivo phospholipase D (PLD) activity of rat thymus was studied after whole‐body X‐irradiation or injection of dexamethasone (DEX). Using exogenous [14C]dipalmitoyl phosphatidylcholine (PC) as the substrate, an elevation of oleate‐activated PLD activity was observed during thymic atrophy. The activity increases were sevenfold at 48 hr after 5‐Gy irradiation and fourfold at 72 hr after injection of 5 mg/kg DEX. The elevation of PLD activity appeared to parallel extensive thymus shrinkage. An increased level of thymic phosphatidic acid (PA), the presumed physiological product of PLD action on PC, was also detected. By comparing the acyl chains of PA with those of other phospholipids, PA appeared to originate from PC. To assess the role of PLD during thymic atrophy, thymocytes and stromal cells were isolated. Although thymocytes themselves exhibited significant PLD activation, the major elevation in PLD activity (greater than fourfold) was found in isolated stromal cells. PLD was also activated during in vitro phagocytosis of apoptotic thymocytes by the macrophage‐like cell line P388D1. This in vitro phagocytosis was significantly inhibited by PLD action blockers, such as 2,3‐diphosphoglycerate and 1‐butanol. These observations strongly suggest that the alteration of oleate‐activated PLD activity is part of an in vivo event in the progression of thymic atrophy, including phagocytic clearance of apoptotic thymocytes.
Phagocytosis of bacille Calmette–Guérin‐infected necrotic macrophages induces a maturation phenotype and evokes antigen‐presentation functions in dendritic cells
Authors: Goldmann Oliver , Rohde Manfred , Medina Eva 
Published: March 2003

SummaryThe interaction of pathogens with dendritic cells (DCs) seems to play a critical role in the initiation of the immune response. Tissue damage and induction of an inflammatory reaction are events frequently associated with the progression of the infection. Although DCs are very efficient at phagocytosing pathogens, the capacity of these cells to uptake microbes from a necrotic environment has not yet been proven. Here we have investigated the ability of murine bone marrow‐derived DCs to maturate and acquire antigen‐presentation functions when cocultured with bacille Calmette–Guérin (BCG)‐infected necrotic macrophages. Immature DCs exhibited a prominent capacity to ingest necrotic material as demonstrated by flow cytometry analysis and confocal microscopy. Furthermore, after exposure to BCG‐infected necrotic macrophages, DCs underwent phenotypic changes, including the up‐regulation of maturation specific markers (major histocompatibility complex class II, CD40, CD80, and CD86) and the capacity to stimulate antigen‐specific CD4+ T cells with higher efficiency than when they were directly infected with a similar number of bacteria. Antigen presentation following phagocytosis of BCG‐infected necrotic macrophages was demonstrated by their ability to stimulate in vitro proliferation and interferon‐γ production of antigen‐specific CD4+ T cells. These results suggest that the functional changes occurring in DCs after interaction with a pathogen can be favoured when the encounter takes place in a necrotic environment and it may constitute an important mechanism for the amplification of class II‐restricted immune responses induced during infection.
Antigen‐specific dose‐dependent system for the study of an inheritable and reversible phenotype in mouse CD4+ T cells
Authors: Firpo Eduardo J. , Kong Raymond K. , Zhou Qinghong , Rudensky Alexander Y. , Roberts James M. , Franza B. Robert 
Published: March 2003

SummaryThe transgenic T‐cell receptor in mouse TEa CD4+ lymphocytes recognizes an endogenous peptide, Eα52‐68, presented in the context of the major histocompatibility complex class II molecule I‐Ab. In response to an optimal peptide concentration TEa cells enter the cell cycle and proliferate. However, a single exposure to high doses of the specific peptide diminished cell expansion upon subsequent restimulation. This hyporesponsive, or anergic, phenotype can still be detected after multiple restimulations indicating that the hyporesponsiveness persists despite cell division and it was inherited by daughter cells. Furthermore, we demonstrated that this hypoproliferative response is associated with high p27Kip1 and cyclin E protein levels, and reduced intracellular interleukin‐2 (IL‐2) expression. Addition of exogenous IL‐2 was required to reset p27Kip1 levels in the progeny derived from hyporesponsive TEa cells. Thus, we have established antigen dose‐dependent induction of a reversible, inheritable (i.e. epigenetic) phenotype and we have identified at least three components of the network of interactions: p27Kip1 cyclin E, and IL‐2 expression.
Mycobacterium bovis bacillus Calmette–Guérin‐infected dendritic cells potently activate autologous T cells via a B7 and interleukin‐12‐dependent mechanism
Authors: Cheadle Eleanor J. , Selby Peter J. , Jackson Andrew M. 
Published: March 2003

SummaryMycobacteria are potent adjuvants, can survive intracellularly and have been safely used for many years as vaccines against tuberculosis and leprosy. They are thus important potential vectors for recombinant vaccines. Many of their adjuvant properties are mediated following phagocytosis by dendritic cells (DC), which are in turn critical for priming naïve T cells. Although the maturation of DC in response to mycobacteria, such as Mycobacterium bovis bacillus Calmette–Guérin (BCG), is well described the subsequent responses of autologous T cells to mycobacterium‐infected DC remains uncharacterized. In our experiments DC infected with BCG expressed more co‐stimulatory molecules than tumour‐necrosis factor‐α (TNF‐α) ‐treated DC and stimulated more potent mixed leucocyte reactions. When autologous T cells were co‐cultured with BCG‐exposed DC they became highly activated, as determined by display of CD25, CD54 and CD71 on both CD4+ and CD8+ cells. In contrast, the response of T cells to TNF‐α‐matured DC was significantly less. Cytokine production from T cells cultured with BCG‐exposed DC was enhanced with elevated secretion of interleukin‐2 (IL‐2), IL‐10 and interferon‐γ (IFN‐γ) and was produced by both CD4+ and CD8+ lymphocytes as determined by intracellular staining. In particular, IFN‐γ secretion was increased from 50 pg/ml to 25 000 pg/ml and IL‐10 secretion increased from 20 pg/ml to 300 pg/ml in BCG‐exposed DC co‐cultures. Blocking antibodies to B7.1 and B7.2 or IL‐12 significantly reduced the secretion of IFN‐γ and reductions were also seen in the expression of CD25 and CD71 by CD4+ cells. These data demonstrate that mycobacterially infected DC are particularly potent activators of autologous T cells compared to TNF‐α‐exposed DC and that the resultant T cells are functionally superior.
Activation of macrophages and interference with CD4+ T‐cell stimulation by Mycobacterium avium subspecies paratuberculosis and Mycobacterium avium subspecies avium
Authors: Zur Lage Susanne , Goethe Ralph , Darji Ayub , Valentin‐Weigand Peter , Weiss Siegfried 
Published: March 2003

Summary Mycobacterium avium subspecies paratuberculosis (M. ptb) and M. avium subspecies avium (M. avium) are closely related but exhibit significant differences in their interaction with the host immune system. The macrophage line, J774, was infected with M. ptb and M. avium and analysed for cytokine production and stimulatory capacity towards antigen‐specific CD4+ T cells. Under all conditions J774 cells were activated to produce proinflammatory cytokines. No influence on the expression of major histocompatibility complex (MHC) class II, intracellular adhesion molecule‐1 (ICAM‐1), B7.1, B7.2 or CD40 was found. However, the antigen‐specific stimulatory capacity of J774 cells for a CD4+ T‐cell line was significantly inhibited after infection with M. ptb, but not with M. avium. When a T‐cell hybridoma expressing a T‐cell receptor identical to that of the T‐cell line was used, this inhibition was not observed, suggesting that costimulation which is essential for the CD4+ T‐cell line is influenced by the pathogenic bacterium M. ptb.
Tumour‐induced polarization of tumour vaccine‐draining lymph node T cells to a type 1 cytokine profile predicts inherent strong immunogenicity of the tumour and correlates with therapeutic efficacy in adoptive transfer studies
Authors: Winter Hauke , Hu Hong‐Ming , Poehlein Christian H. , Huntzicker Erik , Osterholzer John J. , Bashy Jaffar , Lashley David , Lowe Bruce , Yamada Jane , Alvord Gregory , Urba Walter J. , Fox Bernard A. 
Published: March 2003

SummaryPreviously we have shown that vaccination with the poorly immunogenic B16BL6‐D5 melanoma (D5) elicits a dominant type 2 (T2) cytokine response that fails to protect the host from a subsequent tumour challenge. Here we investigated whether the inherent immunogenicity of a tumour can be correlated with its ability to bias the anti‐tumour cytokine response towards either a type 1 (T1) or a T2 profile. The immune response to six tumours of different inherent immunogenicity was assayed. By isolating l‐selectinlow T cells from tumour vaccine draining lymph nodes (TVDLN), it was possible to detect tumour‐specific cytokine responses from both immunogenic, poorly immunogenic and non‐immunogenic tumours. Immunogenic tumours (MCA‐304, MCA‐309, MPR‐4) induced a predominant tumour‐specific T1 cytokine response. In contrast, weakly (MCA‐310, MPR‐3) and poorly/non‐immunogenic tumours (MPR‐5, D5) sensitized T cells with a predominant tumour‐specific T2 cytokine response. A significant correlation (P < 0·025) between immunogenicity and the ratio of tumour‐specific interferon‐γ : interleukin‐4 (IL‐4) secretion by TVDLN T cells was identified. We then documented that non‐therapeutic T cells primed by the poorly immunogenic D5, recognized ‘tumour‐rejection’ antigens and that reprogramming their cytokine response, by in vitro culture with IL‐12 and anti‐IL‐4, to a T1 profile uncovered therapeutic efficacy. In contrast, TVDLN T cells primed by a therapeutic vaccine lose therapeutic efficacy when cultured with IL‐4. These results provide insights into the development of a protective anti‐tumour immune response and strengthen the hypothesis that a T1 cytokine response is critical for T‐cell‐mediated tumour regression.
Towards a framework for evaluating investments in data warehousing
Authors: Counihan Ailish , Finnegan Pat , Sammon David 
Published: March 2003

Abstract.Data warehousing technology offers organizations the potential for much greater exploitation of informational assets. However, the evaluation of potential investments in this technology poses problems for organizations as traditional evaluation methods are constrained when dealing with strategic IT applications. Nevertheless, many organizations are procedurally obliged to use such methods for evaluating data warehousing investments. This paper identifies five problems with using such methods in these circumstances: evaluating intangible benefits; making the relationship between IT and profitability explicit; dealing with the vanishing status quo; dealing with the extended investment time frame; and evaluating infrastructural investments. The authors studied how four organizations in the UK and Ireland attempted to overcome these problems when introducing data warehousing, and propose a framework for evaluating data warehousing investments. This framework consists of a high‐level analysis of the economic environment and of the information intensity of the relationship between the organization and its customers. Based on the outcome of this analysis, the authors propose four factors that have to be managed during the evaluation process in order to ensure that the limitations of the traditional evaluation techniques do not adversely affect the evaluation process. These factors are: commitment and sponsorship; the approach to evaluation; the time scale of benefits; and the appraisal techniques used.
Dissecting insect development: baculovirus‐mediated gene silencing in insects
Authors: Hajós J. P. , Vermunt A. M. W. , Zuidema D. , Kulcsár P. , Varjas L. , De Kort C. A. D. , Závodszky P. , Vlak J. M. 
Published: March 2003

AbstractA novel concept applying baculovirus‐mediated gene silencing to study insect gene function and regulation is described in this paper. A recombinant baculovirus, Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), was constructed with the juvenile hormone esterase (JHE) gene from the tobacco budworm Heliothis virescens in the antisense orientation, driven by the viral p10 promoter. Infection with this recombinant greatly reduced the haemolymph JHE level and resulted in aberrant morphogenesis of final‐instar H. virescens larvae. The body organization remained larval, although the cuticle became hard and brown, similar to pupal cuticle. These results demonstrated that baculovirus‐mediated gene silencing can be accomplished and utilized to dissect insect development and to design a new class of baculovirus insecticides.
Molecular characterization of a peroxiredoxin from the hard tickHaemaphysalis longicornis
Authors: Tsuji N. , Kamio T. , Isobe T. , Fujisaki K. 
Published: March 2003

AbstractAntioxidant enzymes in eukaryotes play an important role in protection against the oxygen radicals generated during aerobic metabolism. Here we report the cloning and characterization of a cDNA encoding the antioxidant enzyme peroxiredoxin from the hard tickHaemaphysalis longicornis(HlPrx). HlPrx is 939 bp long and contains a 101 bp non‐translated sequence at the 5′ end and a polyadenylation singnal followed by a poly(A) tail at the 3′ end. HlPrx encodes a full‐length protein with a predicted molecular mass of 26 kDa that possesses one cysteine residue at amino acid 49 that is conserved among Prx proteins of various species. GenBank™ analysis showed that the deduced amino acid sequence had significant similarity to mammalian and plant Prxs at the amino acid level. A DNA‐nicking assay revealed thatEscherichia coli–expressed recombinant HlPrx (rHlPrx) inhibited oxidative‐nicking of supercoiled plasmid DNA. Two‐dimensional immunoblot analysis with mouse antirHlPrx serum showed reaction with a major constituent protein spot in extracts of adult ticks. In addition, immunoblot analysis showed that rHlPrx was immunoreacted with serum from rabbits repeatedly infested withH. longicornis. Localization analysis using mouse antirHlPrx serum revealed that native HlPrx was highly expressed in the salivary gland of the tick. Moreover, Northern blot analysis showed that the level of HlPrx transcripts was increased during blood sucking. The present results indicate that HlPrx may be an important detoxifying enzyme during the normal life span as well as during blood sucking in ticks.
Transgene expression from the Tribolium castaneum Polyubiquitin promoter
Authors: Lorenzen M. D. , Brown S. J. , Denell R. E. , Beeman R. W. 
Published: March 2003

AbstractThe highly conserved Ubiquitin proteins are expressed from genes with strong, constitutively active promoters in many species, making these promoters attractive candidates for use in driving transgene expression. Here we report the cloning and characterization of the Tribolium castaneum Polyubiquitin (TcPUb) gene. We placed the TcPUb promoter upstream of the coding region of the T. castaneum eye‐colour gene Tc vermilion (Tcv) and injected this construct into embryos from a Tcv‐deficient strain. Transient expression of Tcv during embryogenesis resulted in complete rescue of the larval mutant phenotype. We then incorporated the TcPUb‐Tcv chimera into a piggyBac donor. Resulting germline transformants were easily recognized by rescue of eye pigmentation, illustrating the potential of the TcPUb promoter for use in driving transgene expression.
Antibacterial peptide defensin is involved in midgut immunity of the soft tick, Ornithodoros moubata
Authors: Nakajima Y. , Van Der Goes van Naters‐Yasui A. , Taylor D. , Yamakawa M. 
Published: March 2003

AbstractTwo defensin genes A and B were previously demonstrated to be up‐regulated by blood feeding in the soft tick, Ornithodoros moubata[Nakajima et al. (2001) Two isoforms of a member of the arthropod defensin family from the soft tick, Ornithodoros moubata (Acari: Argasidae). Insect Biochem Mol Biol 31: 747–751]. In this study, two defensin isoforms C and D similar to defensins A and B were newly cloned. A total of four defensins have been identified in O. moubata. All four Ornithodoros defensins are coded as prepro‐defensins. Ornithodoros defensin genes consist of four exons and three introns, an organization reported in mussel defensins but not insect defensins. Ornithodoros defensin C and D genes are predominantly expressed in the midgut and up‐regulated in response to blood feeding. The mature peptide of the previously cloned Ornithodoros defensin A was purified from the midgut lumen, indicating defensin is secreted into the midgut. These findings confirm the involvement of Ornithodoros defensin in midgut immunity.
Rotary Ni‐Ti profile systems for preparing curved canals in resin blocks: influence of operator on instrument breakage
Authors: Mandel E. , Adib‐Yazdi M. , Benhamou L. ‐M. , Lachkar T. , Mesgouez C. , Sobel M. 
Published: March 2003

Mandel E, Adib‐Yazdi M, Benhamou L‐M, Lachkar T, Mesgouez C, Sobel M. Rotary Ni‐Ti profile systems for preparing curved canals in resin blocks: influence of operator on instrument breakage. International Endodontic Journal,32, 436–443 1999.Aim The aim of this study was to determine the incidence of fracture of ProFile 0.4 and 0.6 taper Series 29 nickel‐titanium instruments with respect to operator experience.Methodology A total of 125 simulated root canals in resin blocks with the same geometrical shape in terms of angle and radius of curvature and coronal and apical orifice diameter were used. Five operators prepared all the specimens using an identical step‐down instrument sequence, each one preparing 25 canals. The operators included two endodontists and three general practitioners. Statistical data concerning the incidence of instrument failure was compiled using Statlab and Fisher’s partial least square difference analysis of variance.Results A total of 21 (16.8%) instruments fractured, all had 0.04 tapers. Nine size 25 instruments failed, 9 xsize 20 instruments failed and 3 size 15. During the study, the Binary Tree analysis of instrument failure revealed two operator populations belonging to two different study periods. The first period, which represented the first 13 root canal preparations, was called the ‘learning period’, and the second period, which represented the next 12 sample preparations, was called the ‘application period’. A greater number of instruments failed during the first period than during the second. In the ‘learning period’, both groups of operators learned the same way. In the ‘application period’, two groups could be distinguished; the first group consisted of a general practitioner who produced worse results, and the second group consisted of the other four operators.Conclusions The results indicate the necessity of mastering this rotary canal preparation technique, and the importance of improving competence through learning and experience.
An in vitro study into the effect of the ferrule preparation on the fracture resistance of crowned teeth incorporating prefabricated post and composite core restorations
Authors: Al‐Hazaimeh N. , Gutteridge D. L. 
Published: March 2003

AbstractAimThis in vitro study investigated the effect of a ferrule preparation on the fracture resistance of crowned central incisors incorporating a prefabricated post (Parapost) cemented with Panavia‐Ex and with a composite core.MethodologyThe test group consisted of 10 post crowned natural central incisor teeth with a 2‐mm wide ferrule preparation, whilst the control group of 10 teeth had no ferrule. The specimens were mounted on a Lloyd universal testing machine and a compressive load was applied at an angle of 135 degrees to the palatal surface of the crown until failure occurred.ResultsIn both groups, failure occurred at higher loads compared with previous studies. The mean failure load was 1218 N for the unferruled group and 1407 N for the ferruled group. Statistical analysis showed no significant difference between the groups.ConclusionsUnder the conditions of this study, when composite cement and core materials are utilized with a Parapost prefabricated system invitro the additional use of a ferrule preparation has no benefit in terms of resistance to fracture.
Effects of endodontic instrument handle diameter on electromyographic activity of forearm and hand muscles
Authors: Ozawa T. , Nakano M. , Sugimura H. , Kurayama H. , Tahata K. , Nakamura J. , Shiozawa K. 
Published: March 2003

AbstractAimTo determine the influence of the handle diameter of endodontic instruments on forearm and hand muscle activity using electromyographic (EMG) recording.MethodologySize 45 K‐type files were fitted with four different handle diameters; 3.5, 4.0, 5.0, and 6.0 mm. Seven dentists then attempted to negotiate to the working length acrylic resin root canals with each of the four handle sizes using a reaming motion. EMG activities were recorded from the flexor pollicis brevis muscle (f.p.b.), the flexor carpi radialis muscle (f.c.r.), and the brachioradialis muscle (b) with bipolar surface electrodes. The time taken to negotiate the canals, the area of integrated EMG that corresponded to the amount of EMG activity required during penetration and the maximum amplitude of EMG were measured using the EMG data. Results were analysed statistically using a one‐way factorial anova test and multiple comparison tests.ResultsReaming time and integrated EMG area of each muscle decreased with an increase in handle diameter. The most significant difference in time and area of integrated EMG was detected between handles of 6 mm and 3.5 mm diameter (time: P < 0.01, area of the f.p.b.: P < 0.01, area of the f.c.r. and b: P < 0.05), and between handles of 5 mm and 3.5 mm diameter (P < 0.05). Both 5 mm and 6 mm handles significantly decreased the maximum amplitude of EMG recorded from the f.p.b. compared with 3.5 mm handles (between 3.5 mm and 6 mm: P < 0.01, between 3.5 mm and 5 mm: P < 0.05).ConclusionThe results indicate that handle diameter has an effect on reaming time as well as on muscle activity. As a consequence, handle diameter influenced operator performance during instrumentation.