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Henderson B, Bowen DH. Radiation damage in magnesium oxide. I. Dose dependence of reactor damage. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/4/12/005] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Henderson B, Bowen DH, Briggs A, King RD. Radiation damage in magnesium oxide. II. Effect of pre-irradiation annealing in hydrogen. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/4/12/006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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79
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Codling AJB, Henderson B. Paramagnetic resonance studies of V2+and Cr3+in orthorhombic symmetry sites in magnesium oxide. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/4/10/032] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Henderson B, Wertz JE, Hall TPP, Dowsing RD. An e.p.r. study of vacancy-impurity association in MgO. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/4/1/014] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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82
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McGeehin P, Henderson B, Boas JF, Hall TPP. An EPR study of neutron-irradiated CaO. Observation of the molecular ion OH2-. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/8/11/023] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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84
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Henderson B. Optical pumping cycle of exchange-coupled F+-centre pairs in MgO and CaO. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/9/11/023] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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85
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O'Donnell K, Barklie RC, Henderson B. EPR and optical absorption studies of radiation-produced defects in sodium beta -alumina. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/11/18/022] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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88
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Edel P, d'Aubigne YM, Romestain R, Henderson B, Kappers LA. Photoluminescence properties of additively coloured MgO. I. Effects of uniaxial stress and ODMR. ACTA ACUST UNITED AC 2001. [DOI: 10.1088/0022-3719/12/23/028] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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89
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Henderson B, Tabona P, Poole S, Nair SP. Cloning and expression of the Actinobacillus actinomycetemcomitans thioredoxin (trx) gene and assessment of cytokine inhibitory activity. Infect Immun 2001; 69:154-8. [PMID: 11119501 PMCID: PMC97867 DOI: 10.1128/iai.69.1.154-158.2001] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Thioredoxin is a ubiquitous redox control and cell stress protein. Unexpectedly, in recent years, thioredoxins have been found to exhibit both cytokine and chemokine activities, and there is increasing evidence that this class of protein plays a role in the pathogenesis of inflammatory diseases. In spite of this evidence, it has been reported that the oral bacterium and periodontopathogen Actinobacillus actinomycetemcomitans secretes an immunosuppressive factor (termed suppressive factor 1 [SF1] [T. Kurita-Ochiai and K. Ochiai, Infect. Immun. 64:50-54, 1996]) whose N-terminal sequence, we have determined, identifies it as thioredoxin. We have cloned and expressed the gene encoding the thioredoxin of A. actinomycetemcomitans and have purified the protein to homogeneity. The A. actinomycetemcomitans trx gene has 52 and 76% identities, respectively, to the trx genes of Escherichia coli and Haemophilus influenzae. Enzymatic analysis revealed that the recombinant protein had the expected redox activity. When the recombinant thioredoxin was tested for its capacity to inhibit the production of cytokines by human peripheral blood mononuclear cells, it showed no significant inhibitory capacity. We therefore conclude that the thioredoxin of A. actinomycetemcomitans does not act as an immunosuppressive factor, at least with human leukocytes in cultures, and that the identity of SF1 remains to be elucidated.
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Meghji S, Morrison MS, Henderson B, Arnett TR. pH dependence of bone resorption: mouse calvarial osteoclasts are activated by acidosis. Am J Physiol Endocrinol Metab 2001; 280:E112-9. [PMID: 11120665 DOI: 10.1152/ajpendo.2001.280.1.e112] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We examined the effects of HCO(3)(-) and CO(2) acidosis on osteoclast-mediated Ca(2+) release from 3-day cultures of neonatal mouse calvaria. Ca(2+) release was minimal above pH 7.2 in control cultures but was stimulated strongly by the addition of small amounts of H(+) to culture medium (HCO(3)(-) acidosis). For example, addition of 4 meq/l H(+) reduced pH from 7.12 to 7.03 and increased Ca(2+) release 3.8-fold. The largest stimulatory effects (8- to 11-fold), observed with 15-16 meq/l added H(+), were comparable to the maximal Ca(2+) release elicited by 1,25-dihydroxyvitamin D(3) [1, 25(OH)(2)D(3); 10 nM], parathyroid hormone (10 nM), or prostaglandin E(2) (1 microM); the action of these osteolytic agents was attenuated strongly when ambient pH was increased from approximately 7.1 to approximately 7.3. CO(2) acidosis was a less effective stimulator of Ca(2+) release than HCO(3)(-) acidosis over a similar pH range. Ca(2+) release stimulated by HCO(3)(-) acidosis was almost completely blocked by salmon calcitonin (20 ng/ml), implying osteoclast involvement. In whole mount preparations of control half-calvaria, approximately 400 inactive osteoclast-like multinucleate cells were present; in calvaria exposed to HCO(3)(-) acidosis and to the other osteolytic agents studied, extensive osteoclastic resorption, with perforation of bones, was visible. HCO(3)(-) acidosis, however, reduced numbers of osteoclast-like cells by approximately 50%, whereas 1,25(OH)(2)D(3) treatment caused increases of approximately 75%. The results suggest that HCO(3)(-) acidosis stimulates resorption by activating mature osteoclasts already present in calvarial bones, rather than by inducing formation of new osteoclasts, and provide further support for the critical role of acid-base balance in controlling osteoclast function.
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Royan S, Sharp L, Nair SP, Crean S, Henderson B, Poole S, Scott GL, Evans AW. Identification of the secreted macromolecular immunogens of Staphylococcus aureus by analysis of serum. FEMS IMMUNOLOGY AND MEDICAL MICROBIOLOGY 2000; 29:315-21. [PMID: 11118913 DOI: 10.1111/j.1574-695x.2000.tb01539.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ability of sera to recognise secreted macromolecules of Staphylococcus aureus was examined by ELISA and Western immunoblotting. Individual secreted proteins were also studied using both human sera and sera from rabbits immunised with secreted macromolecules. Patients sera showed a wide range of IgG antibody titres to secreted macromolecules and whole bacteria. Controls showed a significantly lower IgG response. Western immunoblotting revealed that a significant number of secreted proteins were recognised by circulating IgG antibodies. Surprisingly, both the sera from controls and from patients recognised similar macromolecules including a number of potential virulence factors. The major difference was in the IgG binding to a 16-kDa component, which was recognised by the majority of the sera from infected individuals, but only by a small number of sera from healthy controls. The higher incidence of antibodies recognising the 16 kDa component may be related to our earlier finding that the major bone resorbing component of S. aureus is a heterodimeric protein containing a 16-kDa subunit, the activity of which could be blocked by sera.
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McDonagh CM, Henderson B, Imbusch GF. Optical detection of magnetic resonance in the vibronic sidebands of R and N lines in MgO:Cr3+. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/13/32/023] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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93
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McDonagh CM, Henderson B, Imbusch GF, Dawson P. Optical detection of magnetic resonance in MgO:Cr3+. II. Cr3+ions in tetragonal symmetry sites. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/13/17/020] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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94
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Glasbeck M, Sitters R, Henderson B. ODMR in the photo-excited3B1ustate of F22+centres in MgO. I. Zero-field spectra and spin coherence phenomena. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/13/34/003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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95
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McDonagh CM, Henderson B. Exchange interactions between Cr3+ions in magnesium oxide. III. Luminescence and site-selective spectroscopy. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/18/34/012] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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96
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Henderson B, Marshall A, Yamaga M, O'Donnell KP, Cockayne B. The temperature dependence of Cr3+photoluminescence in some garnet crystals. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/21/36/018] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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97
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Bhatti M, MacRobert A, Henderson B, Shepherd P, Cridland J, Wilson M. Antibody-targeted lethal photosensitization of Porphyromonas gingivalis. Antimicrob Agents Chemother 2000; 44:2615-8. [PMID: 10991833 PMCID: PMC90124 DOI: 10.1128/aac.44.10.2615-2618.2000] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We have previously demonstrated that Porphyromonas gingivalis is susceptible to killing by toluidine blue O (TBO) when irradiated with light from a helium-neon (HeNe) laser. The aim of this study was to determine whether a TBO-antibody conjugate (Ab-TBO) could be used to specifically target P. gingivalis to lethal photosensitization in the presence of Streptococcus sanguis or human gingival fibroblasts (HGFs). When a mixture of P. gingivalis and S. sanguis was exposed to 4 microg of TBO/ml and irradiated with HeNe laser light, there were 1.5- and 4.0-log(10)-unit reductions in the viable counts, respectively. In contrast, when TBO was conjugated with a murine monoclonal antibody against P. gingivalis lipopolysaccharide, the reductions in viable counts of P. gingivalis and S. sanguis amounted to 5.0 and 0.1 log(10) units, respectively. Lethal photosensitization of P. gingivalis in the presence of HGFs using unconjugated TBO resulted in a 0.7-log(10)-unit reduction in P. gingivalis viable counts and a 99% reduction in the incorporation of tritiated thymidine ([(3)H]Tdr) by the HGFs. In contrast, when the Ab-TBO conjugate was used, there was a 100% reduction in P. gingivalis viable counts but no significant reduction in the incorporation of [(3)H]Tdr by HGFs. These results demonstrate that specific targeting of P. gingivalis can be achieved using TBO conjugated to a monoclonal antibody raised against a cell surface component of this organism.
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Ranford JC, Coates AR, Henderson B. Chaperonins are cell-signalling proteins: the unfolding biology of molecular chaperones. Expert Rev Mol Med 2000; 2:1-17. [PMID: 14585136 DOI: 10.1017/s1462399400002015] [Citation(s) in RCA: 91] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The chaperonins are a subgroup of oligomeric molecular chaperones; the best-studied examples are chaperonin 60 (GroEL) and chaperonin 10 (GroES), both from the bacterium Escherichia coli. At the end of the 20th century, the paradigm of chaperonins as protein folders had emerged, but it is likely that during the 21st century these proteins will come to be viewed as intercellular signals. Indeed, it is possible that the chaperonins were among the first intercellular signalling proteins to evolve. During the past few years, it has emerged that chaperonin 10 and chaperonin 60 can be found on the surface of various prokaryotic and eukaryotic cells, and can even be released from cells. Secreted chaperonins can interact with a variety of cell types, including leukocytes, vascular endothelial cells and epithelial cells, and activate key cellular activities such as the synthesis of cytokines and adhesion proteins. Much has been made of the high degree of sequence conservation among the chaperonins, particularly in terms of the immunogenicity of these proteins. However, different chaperonin 60 proteins can bind to different cell-surface receptors, including the Toll-like receptors, suggesting that this family of proteins cannot be treated as one biological entity and that several subfamilies may exist. Chaperonins have been implicated in human diseases on the basis of their immunogenicity. The finding that chaperonins can also induce tissue pathology suggests that they may play roles in infections and in idiopathic diseases such as atherosclerosis and arthritis.
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Williams RJ, Ward JM, Henderson B, Poole S, O'Hara BP, Wilson M, Nair SP. Identification of a novel gene cluster encoding staphylococcal exotoxin-like proteins: characterization of the prototypic gene and its protein product, SET1. Infect Immun 2000; 68:4407-15. [PMID: 10899837 PMCID: PMC98335 DOI: 10.1128/iai.68.8.4407-4415.2000] [Citation(s) in RCA: 86] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We report the discovery of a novel genetic locus within Staphylococcus aureus that encodes a cluster of at least five exotoxin-like proteins. Designated the staphylococcal exotoxin-like genes 1 to 5 (set1 to set5), these open reading frames have between 38 and 53% homology to each other. All five proteins contain consensus sequences that are found in staphylococcal and streptococcal exotoxins and toxic shock syndrome toxin 1 (TSST-1). However, the SETs have only limited overall sequence homology to the enterotoxins and TSST-1 and thus represent a novel family of exotoxin-like proteins. The prototypic gene in this cluster, set1, has been cloned and expressed. Recombinant SET1 stimulated the production of interleukin-1beta, interleukin-6, and tumor necrosis factor alpha by human peripheral blood mononuclear cells. PCR analysis revealed that set1 was distributed among other strains of S. aureus but not in the other staphylococcal species examined. Sequence analysis of the set1 genes from different strains revealed at least three allelic variants. The protein products of these allelic variants displayed a 100-fold difference in their cytokine-inducing potency. The distribution of allelic variants of the set genes among strains of S. aureus may contribute to differences in the pathogenic potential of this bacterium.
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Nair SP, Williams RJ, Henderson B. Advances in our understanding of the bone and joint pathology caused by Staphylococcus aureus infection. Rheumatology (Oxford) 2000; 39:821-34. [PMID: 10952735 DOI: 10.1093/rheumatology/39.8.821] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
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