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C J Morris

Publications and source records attributed to C J Morris.

At least 37 records · Page 2Linked to original sources
PubMed1996

Ascorbate promotes low density lipoprotein oxidation in the presence of ferritin.

Whilst catalytic iron has been implicated in the development of atherosclerosis by initiating low density lipoprotein (LDL) oxidation, the source of such iron remains uncertain. Here, we show that LDL oxidation in the presence of ferritin was stimulated by ascorbate (15-60 microM), whilst this effect was inhibited by the iron chelator desferrioxamine. Ascorbate also showed an antioxidant activity at high concentrations (125-250 microM). Our results suggest that the combination of ascorbate with ferritin may supply free iron for LDL oxidation in vivo.

Arteriosclerosis↗
PubMed1996

Activation of the transcription factor nuclear factor-kappaB in human inflamed synovial tissue.

OBJECTIVE: The transcription factor nuclear factor kappaB (NF-kappaB) has been implicated in the inflammatory response and is known to be activated by a process involving reactive oxygen intermediates. The purpose of the present study was to demonstrate the presence and distribution of activated NF-kappaB in synovium samples from patients with rheumatoid arthritis (RA) and osteoarthritis (OA) and from autopsy subjects with no known history of arthritis. METHODS: Immunohistochemical staining was performed using both polyclonal and monoclonal "activity-specific" antibodies to the Rel-A (p65) subunit of NF-kappaB (anti-Rel-A nuclear location sequences). Histologic features of inflammation were also scored. RESULTS: Both antibodies demonstrated positive staining of synovial tissue, with a cellular distribution that was nuclear. The staining was associated with specific cell types within the tissue, in particular, type A synoviocytes and vascular endothelium. Notably, lymphoid aggregates were unstained. Using the monoclonal antibody, a further study was carried out to investigate the distribution of staining in tissues from patients with different disease activities and clinical diagnoses, as well as in normal control tissue obtained at autopsy. Patients with acute RA more commonly showed vessel staining (P = 0.05) and, conversely, showed less frequent staining of the synovial lining (P < 0.005) compared with OA patients. Synovial tissue from controls exhibited either no staining or only weak staining in the synovial lining. CONCLUSION: The activation of NF-kappaB in vascular endothelium and type A synovial lining cells is a feature of synovial tissue from both RA and OA patients. The distribution of this staining appears to be related to the clinical diagnosis.

Aged↗
PubMed1996

Adriamycin stimulates proliferation of human lymphoblastic leukaemic cells via a mechanism of hydrogen peroxide (H2O2) production.

It is becoming clear that adriamycin cytotoxicity may be mediated by semiquinone-free radicals derived from the drug itself and reactive oxygen species (ROS). Recent evidence supports the concept that low concentrations of ROS are able to stimulate cell proliferation, and, based on the observation that subtoxic concentrations of adriamycin can also induce cell proliferation, we hypothesize that low concentrations of adriamycin stimulate cell proliferation by a ROS generation mechanism. We have employed spin-trapping and electron spin resonance (ESR) spectroscopy to investigate the nature of the adriamycin-generated ROS. The spin trap 3,5-dibromo-4-nitrosobenzenesulphonate (DBNBS), which is oxidized in the presence of H2O2 and peroxidase enzymes, was used to produce a characteristic three-line spectrum, and it was found that an identical spectrum was produced by human lymphoblastic leukaemic cells (CCRF-CEM cells) after exposure to adriamycin. We tested our hypothesis further by exposing CCRF-CEM cells to subtoxic concentrations of adriamycin (10(-8), 10(-9) and 10(-10) M) and low concentrations of H2O2 (10(-8), 10(-9) and 10(-10) M) and subsequently monitored cell proliferation. We found that low concentrations of both adriamycin and H2O2 significantly stimulate CCRF-CEM cell proliferation. We therefore conclude that subtoxic concentrations of adriamycin are likely to induce cell proliferation via an H2O2 mediated mechanism.

Cell Division↗
PubMed1996

A synthetic 10-kD heat shock protein (hsp10) from Mycobacterium tuberculosis modulates adjuvant arthritis.

The heat shock protein, hsp10, is an abundant protein in Mycobacterium tuberculosis (Mtb), its nucleotide sequence encoding a protein of 99 amino acids with a molecular mass of 10.7 kD. This sequence is phylogenetically conserved, being represented by the GroES homologue of Escherichia coli. Hsp10 and GroES are members of the chaperonin 10 family of molecular chaperones, and GroEs is necessary for the optimal activity of GroEL, a member of the chaperonin 60 family and the E. coli homologue of mycobacterial hsp65. Since hsp65 has been implicated in both experimental and human rheumatoid arthritis, we aimed to assess the immunomodulatory effects of its co-chaperonin, hsp10, in experimental arthritis. Our results show that an aqueous solution of a mycobacterial hsp10 delayed the onset and severity of adjuvant-induced arthritis in rodents when administered after disease induction but before joint involvement occurred. This biological activity was specific for the hsp10 of Mtb, since neither GroES not the rat homologue was effective. Using synthetic hsp10 fragments, the activity was localized to the N-terminal region of the molecule. Assessment of circulating antibody levels to mycobacterial hsp10 and hsp65 indicated that all arthritic rats had increased titres to both hsp10 and hsp65: hsp10-treated rats showed further elevation of this humoral response not only to hsp10 but also to hsp65 when compared with the untreated arthritic control. This is the first report of the immunomodulatory activity of mycobacterial hsp10 in experimental arthritis, and exhibits a potential role for this co-chaperonin in pathophysiological situations.

Adjuvants, Immunologic↗
PubMed1996

Thrombin receptor expression in rheumatoid and osteoarthritic synovial tissue.

OBJECTIVE: To investigate the possibility that synovial cells might respond to thrombin in the inflamed human joint, using immunohistochemical detection of thrombin receptors. METHODS: Frozen sections of synovial membrane from 20 patients with rheumatoid arthritis, 16 with osteoarthritis, and four normal controls were stained using a monoclonal antibody to the human thrombin receptor. Sections were also double stained for both receptors and non-specific esterase. RESULTS: Receptor positive cells were present in rheumatoid synovia, with some cells also staining positively for non-specific esterase. In contrast, both osteoarthritic and normal synovia contained very few cells expressing receptors. CONCLUSIONS: Thrombin may mediate important pathological changes during chronic inflammatory joint disease.

Arthritis, Rheumatoid↗
PubMed1996

Evaluating the antioxidant potential of new treatments for inflammatory bowel disease using a rat model of colitis.

BACKGROUND: Reactive oxygen species may mediate tissue injury in inflammatory bowel disease. Aminosalicylates have antioxidant activity and the antioxidants, superoxide dismutase and allopurinol, are of reported benefit in inflammatory bowel disease. AIM: To develop a convenient technique for testing the antioxidant potential of standard and novel therapeutic agents for use in inflammatory bowel disease. METHODS: Amplified chemiluminescence was used to measure reactive oxygen species production by colonic biopsy specimens from rats with acetic acid induced colitis and to assess the in vitro effect of conventional antioxidants, standard therapies and proposed novel therapies for inflammatory bowel disease. RESULTS: The model was validated by demonstrating that the profile of effects on chemiluminescence of acetic acid induced colitis biopsy specimens given by conventional antioxidants (sodium azide, catalase, copper-zinc superoxide dismutase, dimethyl sulphoxide, N-acetylcysteine and ascorbate) and standard therapies (5-aminosalicylate and hydrocortisone) resembled that previously reported using biopsy specimens from ulcerative colitis. Human recombinant manganese superoxide dismutase did not alter chemiluminescence. Two novel compounds, LY231617 (10 mM) and amflutizole (20 mM), reduced chemiluminescence by 98% (n = 5, p = 0.009) and 88% (n = 5, p = 0.03), respectively. CONCLUSIONS: The similarity of the chemiluminescence responses of colonic biopsy specimens from acetic acid induced colitis and ulcerative colitis to a range of conventional antioxidants and standard treatments suggests that this model is a useful method for testing the antioxidant potential of new therapies for inflammatory bowel disease. The antioxidant actions of dimethyl sulphoxide, ascorbate, and the novel compounds, amflutizole and LY231617 in this model suggest that these agents merit further assessment in the treatment of inflammatory bowel disease.

Acetic Acid↗
PubMed1996

Effect of mu, delta and kappa opioid receptor agonists on a reactive oxygen species mediated model of skin inflammation.

Opioid agents have been shown to protect against tissue damage caused by hypoxia/reperfusion, an event which has a significant reactive-oxygen-species (ROS) involvement. We have investigated the potential anti-inflammatory activity of three opioid agonists, DAMGO, DPDPE and U50488 in rat skin inflammation induced by the ROS hydrogen peroxide. The model involves the intradermal injection of the enzyme glucose oxidase which converts glucose to D-gluconic acid and H2O2 which is locally released. Following injection, a well-delineated inflammatory response develops rapidly, is maximal at 5 h and still measurable after 48 h. Co-administration of the delta or kappa opioid agonist DPDPE or U50488 (7.5-60 micrograms per site) significantly reduced the inflammation, in a dose-dependent manner, for periods of up to 3 h for DPDPE, and up to 5 h with U50488. The mu-opioid agonist DAMGO (7.5-60 micrograms per site) was ineffective. Co-administration of the opioid antagonist naltrexone (120 micrograms) partially reversed the anti-inflammatory effects of DPDPE and U50488. We conclude that the delta and kappa opioid receptor agonists DPDPE and U50488 are able to inhibit ROS-induced skin inflammation and that this may have clinical implications.

3,4-Dichloro-N-methyl-N-(2-(1-pyrrolidinyl)-cycloh↗
PubMed1995

Reactive oxygen species and iron--a dangerous partnership in inflammation.

Cells of nearly all forms of life require well-defined amounts of iron for survival, replication and expression of differentiated processes. It has a central role in erythropoiesis but is also involved in many other intracellular processes in the tissues of the body. It is the fourth most abundant element in the Earth's crust and the most abundant transition metal in living organisms for which its characteristic chemistry endows it with a series of properties enabling it to fulfil certain biological reactions especially those involving redox mechanisms. It is involved in the transport of oxygen, in electron transfer, in the synthesis of DNA, in oxidations by oxygen (O2) and hydrogen peroxide (H2O2) and in many other processes maintaining normal structure and function of virtually all mammalian cells. Because an iron atom can exist in two valency states, ferrous and ferric, iron became the primordial partner of oxygen in evolution. However, as de Sousa et al. (1989) state, such long standing partnerships have to use protective devices to ensure that the toxicity of neither partner is expressed in the presence of the other. Here, we discuss this dangerous partnership and its relevance to inflammation. The main themes of this review are the known roles of iron in the generation of reactive oxygen intermediates and new developments, including iron and transcription and the reaction of iron with nitric oxide. We also consider the widening recognition of the importance of oxygen metabolites in hypoxia-reperfusion injury and disease of the skin and joint.

Animals↗
PubMed1995

Identification and nucleotide sequences of mxaA, mxaC, mxaK, mxaL, and mxaD genes from Methylobacterium extorquens AM1.

The DNA sequence for a 4.4-kb HindIII-XhoI Methylobacterium extorquens AM1 DNA fragment that is known to contain three genes (mxaAKL) involved in incorporation of calcium into methanol dehydrogenase (I. W. Richardson and C. Anthony, Biochem. J. 287:709-7115, 1992) was determined. Five complete open reading frames and two partial open reading frames were found, suggesting that this region contains previously unidentified genes. A combination of sequence analysis, mutant complementation data, and gene expression studies showed that these genes correspond to mxaSACKLDorf1. Of the three previously unidentified genes (mxaC, mxaD, and orf1), mutant complementation studies showed that mxaC is required for methanol oxidation, while the function of the other two genes is still unknown.

Alcohol Oxidoreductases↗
PubMed1995

PPD and hsp65 induced monoarthritis initiates spontaneous recurrent flares in Lewis rats.

OBJECTIVES: To investigate the time course of a monoarthritis induced with the purified protein derivative of tuberculin (PPD) or a recombinant 65 kDa heat shock protein (rhsp65) in two different strains of sensitised rats. METHODS: Wistar and Lewis rats, sensitised with heat killed Mycobacterium tuberculosis in oil, were challenged intraarticularly with PPD or rhsp65 and monitored for six weeks. Inflammation was assessed by joint swelling, histology, and radiographic studies. RESULTS: Sensitised Lewis rats injected with PPD or rhsp65 showed a chronic response with recurrent spontaneous flares, while Wistar rats showed one inflammatory episode. CONCLUSIONS: The Wistar strain response to PPD resembles a transient reactive arthritis, while the response of the Lewis strain mimics the relapsing nature of rheumatoid synovitis, providing an interesting model to determine dominant immunopathogenic mechanisms.

Acute Disease↗
PubMed1994

Purification and properties of a novel cytochrome: flavocytochrome c from Shewanella putrefaciens.

The major soluble cytochrome isolated from microaerobically grown cells of Shewanella putrefaciens has been shown to be a novel type of flavocytochrome with fumarate reductase activity. This flavocytochrome, located in the periplasmic fraction of cell extracts, has been purified to homogeneity and shown to contain 4 mol of haem c and 1 mol of non-covalently bound FAD per mol of protein. An M(r) value of 63,800 is estimated from sequence analysis assuming 4 mol of haem/mol of protein. In the presence of the artificial electron donor, reduced methyl viologen, the flavocytochrome catalysed the reduction of fumarate but not that of nitrite, dimethylsulphoxide, trimethylamine-N-oxide or sulphite. The pH optimum was 7.4 with calculated pKa values of 6.8 and 8.0 for contributing catalytic groups. The Km and kcat. values for fumarate reduction were 21 microM and 250 s-1 respectively, whereas the corresponding values for succinate oxidation with 2,6-dichlorophenol-indophenol as electron carriers were 200 microM and 0.07 s-1 respectively. Mesaconic acid was a competitive inhibitor of fumarate reduction with a Ki of 2 microM. Zymogram staining of polyacrylamide gels with purified protein showed a band of fumarate reductase activity. Polyclonal antibodies, raised to the purified flavocytochrome, were shown to titrate out fumarate reductase activity. We conclude that the physiological role of this enzyme is as a fumarate reductase. Optical absorption spectra of the flavocytochrome indicated that all the haems were of the c-type and gave alpha, beta and gamma peaks at 552.3, 523 and 418 nm in the reduced spectrum with epsilon values of 30.2, 15.9 and 188.2 mM-1.cm-1 respectively. Oxidized spectra showed no 695 nm band that would be indicative of His-Met coordination. Two redox potentials were resolved at -220 mV and -320 mV. The cytochrome was reduced by formate in the presence of particulate cell fractions. The relationship of this cytochrome to other low-potential flavocytochromes c is discussed.

Amino Acids↗
PubMed1994

Isolation, phenotypic characterization, and complementation analysis of mutants of Methylobacterium extorquens AM1 unable to synthesize pyrroloquinoline quinone and sequences of pqqD, pqqG, and pqqC.

Aerobic gram-negative methylotrophs oxidize methanol to formaldehyde by using a methanol dehydrogenase that has pyrroloquinoline quinone (PQQ) as a prosthetic group. Seventy-two mutants which are unable to grow on methanol unless the growth medium is supplemented with PQQ have been isolated in the facultative methanol utilizer Methylobacterium extorquens AM1. In addition, 12 previously isolated methanol oxidation mutants of M. extorquens AM1 were shown to be able to grow on methanol in the presence of PQQ. These putative PQQ biosynthesis mutants have been complemented by using previously isolated clones containing M. extorquens AM1 DNA, which were known to contain genes necessary for oxidation of methanol to formaldehyde (mox genes). Subcloning and transposon mutagenesis experiments have assigned these mutants to five complementation groups in two gene clusters. Representatives of each complementation group were shown to lack detectable PQQ in the growth medium and in cell extracts and to contain methanol dehydrogenase polypeptides that were inactive. Therefore, these mutants all appear to be defective in PQQ biosynthesis. PQQ biosynthesis mutants of Methylobacterium organophilum DSM 760 and M. organophilum XX were complemented by using M. extorquens AM1 subclones, and PQQ biosynthesis mutants of M. extorquens AM1 and M. organophilum XX were complemented by using M. organophilum DSM 760 subclones. This analysis suggested that a total of six PQQ biosynthesis complementation groups were present in M. extorquens AM1 and M. organophilum DSM 760. A 2-kb M. extorquens AM1 DNA fragment that complemented the MoxO class of PQQ biosynthesis mutants was sequenced and found to contain two complete open reading frames and the N-terminal sequence of a third. These genes designated pqqDGC, had predicted gene products with substantial similarity to the gene products of corresponding pqq genes in Acinetobacter calcoaceticus and Klebsiella pneumoniae. pqqD encodes a 29-amino-acid peptide which contains a tyrosine residue and glutamate residue that are conserved in the equivalent peptides of K. pneumoniae, PqqA (23 amino acids), and A. calcoaceticus, PqqIV (24 amino acids), and are thought to be the precursors for PQQ biosynthesis. The organizations of a cluster of five PQQ biosynthetic genes appear to be similiar in four different bacteria (M. extorquens AM1, M. organophilum DSM 760, K. pneumoniae, and A. calcoaceticus). Our results show that a total of seven pqq genes are present in M. extorquens AM1, and these have been designated pqqDGCBA and pqqEF.

Amino Acid Sequence↗
PubMed1994

Arthritogenic potential of the 65 kDa stress protein--an experimental model.

OBJECTIVES: To assess the effect of an intra-articular presentation of stress (heat shock) proteins (hsp) on joint inflammation. METHODS: Wistar rats were sensitised with a suspension of heat killed Mycobacterium tuberculosis in oil in the scruff of the neck and challenged intra-articularly with stress protein or M tuberculosis preparations. Inflammation was assessed by joint swelling and, using immunohistology, cellular infiltration of the synovium and antibody induction by an enzyme-linked immunosorbent method. RESULTS: It was shown, for the first time, that the intra-articular administration of a recombinant myobacterial 65 kDa hsp can induce joint inflammation in M tuberculosis sensitised recipients; both powdered M tuberculosis and the purified protein derivative of tuberculin (PPD) produced a similar response, with T cell infiltration of the synovium and a time course typical of delayed type hypersensitivity. This response was specific to the 65 kDa protein as another immunodominant mycobacterial stress protein of 10 kDa was ineffective. Furthermore, intra-articular injection of the 65 kDa hsp induced an antibody response against both the 65 kDa and 10 kDa proteins and the antibody titres continued to rise when knee swelling had subsided. CONCLUSIONS: These results support the hypothesis that 60 kDa proteins are a relevant arthritogenic stimulus in an M tuberculosis background. Moreover, when antigen presentation occurs in the synovium of previously sensitised individuals, circulating antibodies are generated which persist and recognise cross-reactive epitopes on several stress proteins.

Animals↗
PubMed1994

Proinflammatory effects of morphine in the rat adjuvant arthritis model.

Morphine has been shown to alter various aspects of the immune response. We examined its effect on progression of the T-cell-mediated model, rat adjuvant arthritis. Saline, morphine or the opioid antagonist naloxone were administered to male Wistar rats via subcutaneous osmotic pumps implanted three days prior to adjuvant disease induction by an intra-dermal injection of Mycobacterium tuberculosis in oil. The time of disease onset was found to be accelerated (day 11) for the morphine group as compared to the saline control (day 13). In addition morphine produced a significant increase in paw swelling (days 13 and 14), bone demineralization and bone erosions. A significant decrease in body weight as compared to the saline control was also observed. Naloxone had no significant effect on the degree of the inflammation seen, although like morphine it significantly increased bone demineralization and bone erosions as assessed by radiography.

Animals↗
PubMed1993

Free radicals in inflammation: second messengers and mediators of tissue destruction.

In recent years it has become increasingly apparent that, in man, free radicals play a role in a variety of normal regulatory systems, the deregulation of which may play an important role in inflammation. As examples, we discuss the second messenger roles of: NO in the regulation of vascular tone, O2.- in fibroblast proliferation and H2O2 in the activation of transcription factors such as NF kappa B. Other control mechanisms, the physiological function of which may be perturbed in inflammation, include: the oxidative modification of low density lipoprotein, the oxidative inactivation of alpha-1-protease inhibitor, DNA damage/repair and heat shock protein synthesis. At sites of inflammation, increased free radical activity is associated with the activation of the neutrophil NADPH oxidase and/or the uncoupling of a variety of redox systems, including endothelial cell xanthine dehydrogenase. Although free radicals, thus produced, have the capacity to mediate tissue destruction, either alone or in concert with proteases, we argue that disturbances in the second messenger and regulatory activities of free radicals may also contribute significantly to the inflammatory process.

Antioxidants↗
PubMed1993

Presence of foam cells containing oxidised low density lipoprotein in the synovial membrane from patients with rheumatoid arthritis.

OBJECTIVE: Increased concentrations of lipid peroxidation products have been described in the serum and synovial fluid from patients with rheumatoid arthritis. A large proportion of the unsaturated lipids in human extracellular fluids is a component of low density lipoprotein (LDL). The oxidative modification of LDL, and its subsequent uptake by macrophages, has been implicated in the pathogenesis of atherosclerosis, but not of rheumatoid arthritis. This study aimed to assess whether oxidatively modified LDL was present in the rheumatoid synovium. METHODS: A polyclonal antiserum raised in rabbits against oxidised LDL (o-LDL) was used to perform an immunohistochemical study of a series of synovial biopsy specimens from patients with rheumatoid arthritis. RESULTS: Collections of positively stained macrophages, arranged in a linear fashion and with the morphological characteristics of foam cells--that is, 'fatty streaks', were identified around blood vessels within the intimal connective tissue. In addition, scattered, positively stained foam cells were present in association with deposits of fibrin. These staining patterns were absent from control synovial membranes (traumatic knee injuries). CONCLUSIONS: The findings in all rheumatoid patients studied suggest that atherosclerosis and rheumatoid arthritis have analogous pathogenetic features.

Arthritis, Rheumatoid↗