bluuebunny/crossref_metadata_2025_split huggingface dataset:
Endotoxin, but not platelet‐activating factor, activates nuclear factor‐κB and increases IκBα and IκBβ turnover in enterocytes
Authors: De Plaen Isabelle G. , Qu Xiao‐Wu , Wang Hao , Tan Xiao‐Di , Wang Liya , Han Xin‐Bing , Rozenfeld Ranna A. , Hsueh Wei 
Published: March 2003

SummaryBacterial endotoxin (lipopolysaccharide; LPS) and platelet‐activating factor (PAF) are important triggers of bowel inflammation and injury. We have previously shown that LPS activates the transcription factor nuclear factor (NF)‐κB in the intestine, which up‐regulates many pro‐inflammatory genes. This effect partly depends on neutrophils and endogenous PAF. However, whether LPS and PAF directly activate NF‐κB in enterocytes remains controversial. In this study, we first investigated the effect of LPS and PAF on NF‐κB activation in IEC‐6 (a non‐transformed rat small intestinal crypt cell line) cells, by electrophoresis mobility shift assay and supershift, and found that LPS, but not PAF, activates NF‐κB mostly as p50–p65 heterodimers. The effect was slower than tumour necrosis factor (TNF). Both LPS and TNF induce the expression of the NF‐κB‐dependent gene inducible nitric oxide synthase (iNOS), which occurs subsequent to NF‐κB activation. We then examined the effect of LPS and TNF on the inhibitory molecules IκBα and IκBβ. We found that TNF causes rapid degradation of IκBα and IκBβ. In contrast, LPS did not change the levels of IκBα and IκBβ up to 4 hr (by Western blot). However, in the presence of cycloheximide, there was a slow reduction of IκBα and IκBβ, which disappeared almost completely at 4 hr. These observations suggest that LPS causes slow degradation and synthesis of IκBα and IκBβ and therefore activates NF‐κΒ via at least two mechanisms: initially, through an IκB‐independent mechanism, and later, via an increased turnover of the inhibitor IκB. NF‐κΒ activation precedes the gene expression of iNOS (assayed by reverse transcription–polymerase chain reaction), suggesting that LPS up‐regulates iNOS via this transcription factor.
Macrophage phagocytosis of foot‐and‐mouth disease virus may create infectious carriers
Authors: Rigden Rachael C. , Carrasco Carlos P. , Summerfield Artur , MCCullough Kenneth C. 
Published: March 2003

SummaryMacrophages play critical roles in innate defences against virus infections, particularly pertinent to the rapid immune response required following emergency vaccination against foot‐and‐mouth disease virus (FMDV). Consequently, macrophage–FMDV interaction was studied in vitro, in the absence of specific antibodies, to mimic the animal early postvaccination. A gradual loss of infectivity and viral antigen was observed over 48 hr, and no evidence of productive virus replication was found. From the pathological viewpoint, an important observation was that the majority of macrophages carried infectious virus for at least 10 hr. Pronase and mild acid treatments showed the virus to be primarily on the cell surface during the first 4 hr. Thereafter, it became internalized (pronase‐ and pH resistant), but remained infectious for 10–24 hr. The internalization process was dependent on microfilament activity, while the survival of infectious virus related to live virus‐dependent inhibition of macrophage protein synthesis. Infectious centre assays demonstrated that this infectious virus – whether on the cell surface or internalized – was actually being released from the cells. This is interesting considering that FMDV is highly pH labile. Together, these characteristics suggest that the virus had been internalized by a process such as macropinocytosis, and fusion with endosomes was delayed or impaired. This mechanism whereby the virus could ‘piggyback’ on or in the macrophage, becoming internalized but not degraded for at least 10 hr, are important considerations in FMD pathogenesis. Such ‘virus‐transporting’ macrophages would be in a position to carry infectious FMDV to different sites in the body, where it could be released to infect other cells for replication.
Expression and regulation of the pattern recognition receptors Toll‐like receptor‐2 and Toll‐like receptor‐4 in the human placenta
Authors: Holmlund Ulrika , Cebers Gvido , Dahlfors Agneta R. , Sandstedt Bengt , Bremme Katarina , EkstrÖm EVA S. , Scheynius Annika 
Published: March 2003

SummaryThe placenta constitutes a physical and immunological barrier against invading infectious agents and has been suggested to be a pregnancy‐specific component of the innate immune system. The aim of this study was to investigate the presence and regulation of Toll‐like receptors‐2 and ‐4 (TLR2 and TLR4) in the human placenta, because these receptors are believed to be important for immune responses against pathogens. Twenty‐eight placentas from normal term pregnancies were analysed with immunohistochemistry, which showed a strong immunoreactivity for TLR2 and TLR4 in the villous and the intermediate trophoblasts. The regulation of TLR2 and TLR4 by microbial stimulus was assessed by incubating explants of term chorionic villi with zymosan or lipopolysaccharide (LPS) and analysed with real‐time reverse transcriptase–polymerase chain reaction. Stimulation with zymosan and LPS readily induced interleukin (IL)‐6 and IL‐8 cytokine production in the placenta cultures, whereas TLR2 and TLR4 mRNA and protein expression remained at the same high level as in unstimulated explants. These data suggests a novel mechanism for the fetoplacental unit to interact with micro‐organisms.
Cytokines in Lyme borreliosis: lack of early tumour necrosis factor‐α and transforming growth factor‐β1 responses are associated with chronic neuroborreliosis
Authors: Widhe Mona , Grusell Mattias , Ekerfelt Christina , Vrethem Magnus , Forsberg Pia , Ernerudh Jan 
Published: March 2003

SummaryThe clinical outcome of the tick born infection Lyme borreliosis seems to be influenced by the type of immune response mounted during the disease, as suggested by various animal models. Here we report the serum and cerebrospinal fluid levels of tumour necrosis factor‐α (TNF‐α), transforming growth factor β1 (TGF‐β1) and interleukin‐6 (IL‐6) in samples drawn at different disease intervals during the course of non‐chronic neuroborreliosis (n=10), chronic neuroborreliosis (n=15), erythema migrans (n=8, serum only) and controls (n=7). When comparing early neuroborreliosis cerebrospinal fluid samples, significantly higher levels of TNF‐α were found in non‐chronic patients than in chronic patients (P<0·05). Moreover, TGF‐β1 was increased in the early serum samples of non‐chronic patients, as compared to chronic patients (P<0·01). Elevated serum levels of TGF‐β1 were also found in erythema migrans as compared to neuroborreliosis and controls (P<0·05). The high TNF‐α levels noted in early cerebrospinal fluid samples of non‐chronic patients only, possibly reflects an ongoing pro‐inflammatory immune response in the central nervous system, which could be beneficial in eliminating disease. High serum levels of TGF‐β1 probably mirror an anti‐inflammatory response, which might play a role in controlling the systemic immune response.
Mycobacteria, an environmental enhancer of lupus nephritis in a mouse model of systemic lupus erythematosus
Authors: Hawke Christine G. , Painter Dorothy M. , Kirwan Paul D. , Van Driel Rosemary R. , Baxter Alan G. 
Published: March 2003

SummarySystemic lupus erythematosus (SLE) is a chronic systemic autoimmune disease characterized by the production of antibodies directed against self antigens. Immune complex glomerulonephritis (GN) is one of the most serious complications of this disorder and can lead to potentially fatal renal failure. The aetiology of SLE is complex and multifactorial, characterized by interacting environmental and genetic factors. Here we examine the nature of the renal pathology in mycobacteria‐treated non‐obese diabetic (NOD) mice, in order to assess its suitability as a model for studying the aetiopathogenesis of, and possible treatment options for, lupus nephritis (LN) in humans. Both global and segmental proliferative lesions, characterized by increased mesangial matrix and cellularity, were demonstrated on light microscopy, and lesions varied in severity from very mild mesangiopathic GN through to obliteration of capillary lumina and glomerular sclerosis. Mixed isotype immune complexes (IC) consisting of immunoglobulin G (IgG), IgM, IgA and complement C3c were detected using direct immunofluorescence. They were deposited in multiple sites within the glomeruli, as confirmed by electron microscopy. The GN seen in mycobacteria‐treated NOD mice therefore strongly resembles the pathology seen in human LN, including mesangiopathic, mesangiocapillary and membranous subclasses of LN. The development of spontaneous mixed isotype IC in the glomeruli of some senescent NOD mice suggests that mycobacterial exposure is accelerating, rather than inducing, the development of GN in this model.
Recognition of bovine respiratory syncytial virus proteins by bovine CD8+ T lymphocytes
Authors: Gaddum Ruth M. , Cook Roy S. , Furze Julie M. , Ellis Shirley A. , Taylor Geraldine 
Published: March 2003

SummaryCD8+ T lymphocytes play a major role in the clearance of bovine respiratory syncytial virus (BRSV), an important respiratory pathogen of young calves that shares many of the epidemiological and pathological features of human respiratory syncytial virus (HRSV) in infants. Recombinant vaccinia virus (rVV) and recombinant fowlpox virus (rFPV), expressing individual BRSV proteins, were used to demonstrate that the F, N and M2 proteins were the major antigens recognized by bovine CD8+ T cells in major histocompatibility complex (MHC)‐defined cattle. BRSV protein recognition by CD8+ T cells was analysed using cytotoxic T lymphocyte (CTL) assays or by the production of interferon‐γ (IFN‐γ) following restimulation with BRSV proteins. Strong recognition of the G protein by CD8+ T cells was observed in cattle that had been vaccinated with rVV expressing this protein and subsequently challenged with BRSV. Although there is variation in the number of expressed MHC genes in cattle with different class I haplotypes, this did not appear to influence BRSV protein recognition by CD8+ T cells. Knowledge of the antigenic specificity of BRSV‐specific CD8+ T cells will facilitate the qualitative and quantitative analysis of BRSV‐specific CD8+ T‐cell memory in cattle and help to ensure that potential vaccines induce a qualitatively appropriate CD8+ T‐cell response.
Macrophages exposed to Mycobacterium tuberculosis release chemokines able to recruit selected leucocyte subpopulations: focus on γδ cells
Authors: Ferrero Elisabetta , Biswas Priscilla , Vettoretto Katuscia , Ferrarini Marina , Uguccioni Mariagrazia , Piali Luca , Leone Biagio Eugenio , Moser Bernhard , Rugarli Claudio , Pardi Ruggero 
Published: March 2003

SummaryGranuloma is a typical feature of tuberculosis. We evaluated the chemotaxis of selected human leucocyte subsets induced by macrophages incubated with Mycobacterium tuberculosis (MT)‐derived products in vitro. The release of monocyte chemotactic protein 1 (MCP‐1) and interleukin‐8 (IL‐8) correlated with the specific induction of strong chemotaxis towards monocytes and polymorphonuclear leucocytes (PMNs). γδ and T helper type 1 (Th1) αβ lymphocytes were chemoattracted, while T‐resting, IL‐2‐activated and Th2 lymphocytes were unaffected. Activation with mycobacterium‐derived, phosphate‐containing components, modulated the chemokine receptor profile of γδ T lymphocytes as well as their pattern of cyto‐chemokine production, disclosing a potential for their active participation in granuloma formation. In particular, CXCR3 and IP‐10, which we found to be released by MT‐pulsed alveolar macrophages, seem to represent the receptor–counter‐receptor pair implicated in the chemotaxis of γδ lymphocytes. Immunohistochemical analysis and in situ hybridization revealed the in vivo presence of IL‐8, MCP‐1 and IL‐10 in lymph node and lung tuberculous granulomas. Our results underscore the role of MT extracts in the induction of macrophage‐derived chemokines responsible for the orchestrated recruitment of PMNs, monocytes, and Th1 and γδ T cells, as well as in the regulation of γδ function.
Genetic variation in geographical populations of western and Mexican corn rootworm
Authors: Szalanski A. L. , Roehrdanz R. L. , Taylor D. B. , Chandler L. 
Published: March 2003

AbstractGenetic variation in the nuclear rDNA ITS1 region of western corn rootworm, Diabrotica virgifera virgifera (WCR), and Mexican corn rootworm, D. v. zeae (MCR) was studied. Two sites were detected which differentiated WCR and MCR in the 642‐base sequence. Polymerase chain reaction–restriction fragment length polymorphism (PCR‐RFLP) analysis of the first internal transcribed spacer region (ITS1) sequence revealed no variation within or among the twelve WCR and two MCR populations. PCR‐RFLP of 75% of the mitochondrial DNA genome detected one significant polymorphic site out of the approximately 190 restriction sizes observed in WCR. The polymorphism did not differentiate geographical populations of WCR and is not diagnostic for the subspecies. The low levels of variation observed in WCR suggests either high levels of gene flow or a recent geographical expansion from a relatively small base. Gene flow would facilitate the rapid spread of traits that could compromise control programmes, such as insecticide resistance or behavioural modifications. The minimal genetic differentiation between WCR and MCR raises questions about the evolutionary history of these subspecies and how the distinct phenotypes are maintained.
Sequence and evolution of a hexamerin from the ant Camponotus festinatus
Authors: Martínez T. , Burmester T. , Veenstra J. A. , Wheeler Diana 
Published: March 2003

AbstractIn the ant Camponotus festinatus, two different hexamerins accumulate stage‐specifically during the late larval period and at various times in adults. These hexamerins serve as storage proteins and play important roles in brood nourishment and colony founding. We report an analysis of the cDNA sequence of C. festinatus hexamerin 2 (CfeHex2). The native protein contains 732 amino acids, which are moderately enriched in aromatic amino acids, aspartate and asparagine. Phylogenetic analyses show a close relationship of CfeHex2 to a putative toxin of the braconid wasp, Bracon hebetor. The divergence of Formicidae and Braconidae hexamerins was calculated to have begun 187 MYA, an estimate consistent with currently accepted phylogeny of insect orders.
Cytochrome P450s CYP6D3 and CYP6D1 are part of a P450 gene cluster on autosome 1 in the house fly
Authors: Kasai S. , Scott J. G. 
Published: March 2003

AbstractThe P450 monooxygenases of insects are important in the metabolism of numerous endogenous and exogenous compounds. However, identity of the P450 isoform(s) involved in these reactions is rarely known. A critical first step in the identification of important P450s is the cloning and sequencing of their genes. Toward this goal we report the genomic sequence of a new cytochrome P450, termed CYP6D3, from the house fly, Musca domestica. CYP6D3 is part of a P450 gene cluster located on chromosome 1 and is located upstream of a related gene, CYP6D1. The similar genetic structures of CYP6D3 and CYP6D1 (5 exons and 4 introns of similar length) suggest one of these genes may have been the result of a duplication event. The CYP6D3 deduced amino acid sequence indicates a protein with 518 amino acids and a molecular weight of 59.3 kDa. The CYP6D3 protein is most similar to house fly CYP6D1 (78%) and Cyp6D2 (56%) from Drosophila melanogaster. The deduced amino acid sequences of CYP6D3 and CYP6D1 are identical at the Helix I and heme binding regions.
Molecular evolution of thecacophonyIVS6 region in sandflies
Authors: Lins R. M. M. A. , Oliveira S. G. , Souza N. A. , De Queiroz R. G. , Justiniano S. C. B. , Ward R. D. , Kyriacou C. P. , Peixoto A. A. 
Published: March 2003

AbstractA number of insects produce acoustic signals during courtship. Genes involved in the control of the courtship song are particularly interesting from an evolutionary viewpoint because interspecific variation in this signal is potentially important as a reproductive isolation mechanism and, as a consequence, in the speciation process. Thecacophonygene was identified by a mutation affecting the ‘lovesong’ inDrosophila melanogaster. Phlebotomine sandflies (Diptera: Psychodidae) also produce acoustic stimuli during courtship and thereforecacophonycan be used as an interesting molecular marker in evolutionary studies in these important disease vectors. In this paper we have studied the molecular evolution of the IVS6 region ofcacophonyin sandflies. We compared the level of divergence in the exon sequences encoding this conserved domain inDrosophilaand Phlebotomines. We also analysed the high level of variation in an intron that is present in sandflies but that was lost inDrosophiladuring evolution. The availablecacophonysequences were also used for a phylogenetic analysis of some species of the Neotropical genusLutzomyia.
Differential expression and induction of two Drosophila cytochrome P450 genes near the Rst(2)DDT locus
Authors: Brandt A. , Scharf M. , Pedra J. H. F. , Holmes G. , Dean A. , Kreitman M. , Pittendrigh B. R. 
Published: March 2003

AbstractPrevious studies have shown that the major metabolic resistance locus in the insecticide‐resistant Drosophila line Rst(2)DDTWisconsin maps between the markers cn and vg on chromosome 2. Six cytochrome P450 genes exist in this region. We investigated the expression levels of these P450 genes in DDT‐resistant and ‐susceptible fly lines. We report: (i) DDT resistance is significant (> 30‐fold) and dominant, (ii) resistance is reduced by the cytochrome P450 inhibitor PBO, (iii) there is constitutive over‐expression relative to susceptible flies of two genes encoding cytochrome P450 enzymes within the cn‐vg region (CYP6G1 = 4.3‐fold; CYP12D1 = 6.0‐fold), and (iv) exposure to DDT results in an increased expression of only one of these two P450 genes (CYP12D1  ≥ 6‐fold above constitutive resistant fly baselines).
Surgical extrusion of crown‐root‐fractured teeth: a clinical review
Authors: Çalisşkan M. K. , Türkün M. , Gomel M. 
Published: March 2003

Aim In this clinical study, combined surgical and endodontic treatment was performed in 20 cases of crown‐root fracture and the outcomes reviewed.Methodology Surgical treatment involved a conventional extraction and stabilization technique. Root canal treatment using calcium hydroxide was performed. Before root canal obturation, a calcium hydroxide dressing was maintained for 3 months.Results Follow‐up examinations, which varied between 6 and 36 (mean 14.5) months, showed that there were no radiographic and clinical signs of progressive root resorption, marginal bone loss or periapical disease in all except one case.Conclusions The favourable results of this study demonstrate that surgical extrusion in teeth with crown‐root fractures may be an alternative treatment to orthodontic extrusion.
Detection of bacterial virulence genes associated with infective endocarditis in infected root canals
Authors: Bate A. L. , Ma J. K‐C. , Ford T. R. Pitt 
Published: March 2003

Aim  The aim of this study was to examine whether bacteria associated with root canals possess genes that might predispose to bacterial colonization of the endocardium.Methodology  Oligonucleotides were designed from DNA sequences encoding the functional binding regions of streptococcal fibronectin‐binding protein (FnBP) and staphylococcal fibrinogen‐binding protein (FgBP). The specificity and cross‐reactivity of the oligonucleotide primers were investigated; streptococcal primers were tested for recognition of FnBP genes in other strains of streptococci, and the staphylococcal primers for detection of FgBP from other staphylococci. Interspecies specificity of these primers was also investigated. In a pilot clinical study, the pulp chambers of 16 nonvital teeth without sinus tracts, were opened aseptically. Root canal samples were collected, along with samples from the gingival sulcus and anterior nares. From these samples DNA was extracted, subjected to polymerase chain reaction (PCR) and analysed by agarose gel electrophoresis.Results  Using the streptococcal FnBP primers, PCR bands were amplified from eight root canal samples, eight gingival samples and three nasal samples. With the staphylococcal primers, PCR bands were amplified from seven root canals, 11 gingival and nine nasal samples. This study showed that PCR could be used to detect bacteria in root canals that possess genes with homology to functional regions of those encoding FnBP or FgBP.Conclusions  If bacteria in root canals possess FnBP or FgBP, they may have the potential to cause infective endocarditis.
Effect of sodium hypochlorite on mechanical properties of dentine and tooth surface strain
Authors: Sim T. P. C. , Knowles J. C. , Ng Y‐L. , Shelton J. , Gulabivala K. 
Published: March 2003

AbstractAimThe aim of this study was to test the null hypothesis that sodium hypochlorite irrigation of root canals does not alter the properties of dentine and contribute to the weakening of root‐treated teeth.MethodologyThe effect of two concentrations (0.5%, 5.25%) of sodium hypochlorite (NaOCl) and saline on (i) the elastic modulus and flexural strength of machined dentine bars, and (ii) changes in strain of ‘whole’ extracted human teeth were evaluated. One hundred standardized plano‐parallel dentine bars (> 11.7 × 0.8 × 0.8 mm) were randomly divided into the three groups, immersed for 2 h in the respective solutions and then subjected to a three‐point bend test. Changes in strain of each of 10 teeth on cyclical nondestructive occlusal loading were measured using electrical resistance strain gauges bonded to the cervical aspects. Each tooth had its crown and enamel reduced and root canal prepared. These were irrigated sequentially in a series of four separate, 30‐minute regimes; initial‐saline, 0.5% NaOCl, 5.25% NaOCl and final‐saline. The changes in strains after each irrigation regime were compared.ResultsThere was a significant decrease in elastic modulus of the dentine bars immersed in 5.25% NaOCl compared with the saline group (P < 0.01). There was also a significant decrease in flexural strength of the dentine bars in the 5.25% NaOCl group compared to both the saline and 0.5% NaOCl groups (P < 0.01). The strain data from the nondestructive tooth loading tests revealed significant increases in tensile strain between the initial‐saline and the final‐saline stages (P < 0.01). Significant increases in compressive strains were also found between initial‐saline and 5.25% NaOCl; and between 0.5% NaOCl and 5.25% NaOCl stages (P < 0.01).ConclusionsThe null hypothesis was rejected, 5.25% NaOCl reduced the elastic modulus and flexural strength of dentine. Irrigation of root canals of single, mature rooted premolars with 5.25% NaOCl affected their properties sufficiently to alter their strain characteristics when no enamel was present.