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Dietetics, Nutrition and Biological Sciences

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Author: search.filters.author.Fyfe, LornaEnd date: 2009

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Now showing 1 - 10 of 28
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    The Inhibition of Free Radical Generation by Preparations of Harpagophytum procumbens in vitro
    (2009-01) Grant, L.; McBean, Douglas; Fyfe, Lorna; Warnock, Mary
    Harpagophytum procumbens (Hp), commonly known as Devil's Claw has been used as a traditional treatment for a variety of illnesses for centuries. Since the early twentieth century, it has become a popular antiinflammatory and analgesic preparation amongst European herbalists for supportive or adjuvant treatment of degenerative joint diseases. Extracts of Hp tubers have demonstrated antiinflammatory and analgesic effects in animal models of inflammation and in human trials. The mechanism(s) of action responsible for these attributes, however, remain to be elucidated. Reactive oxygen species generated in acute and chronic inflammatory diseases are known to be cytotoxic and can cause tissue damage. In this study, a root tuber extract (Hp extract) and commercially available tincture (Hp tincture) were investigated for antioxidant characteristics using in vitro test systems. Both preparations were found to effectively scavenge DPPH radical, inhibit nitrite levels in supernatants harvested from LPS-stimulated RAW 264.7 macrophages, and cause dose-dependent suppressions in the detection of fMLP-and AA-induced neutrophil MPO. The antioxidant effects demonstrated for both preparations of Hp may contribute to the antiinflammatory and analgesic properties observed for the plant. Copyright © 2008 John Wiley & Sons, Ltd
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    Phenotypic changes in the lipopolysaccaride of Pseudomonas aeruginosa and E.coli grown in milk-based enteral nutrient solutions
    (Elsevier, 1999-01) Hodgson, Ian; Stewart, John; Fyfe, Lorna
    Previous studies have shown enteral nutritional solutions (ENS) contaminated with large numbers of microorganisms from the environment or gastrointestinal (GI) tract of patients have caused respiratory infections, acute and chronic enteritis, and septicemia. The introduction of closed- enteral feeding systems has been used to prevent contaminating organisms from entering enteral feeding systems in large numbers. However, there is some discussion as to whether this has been an effective measure in reducing ENS-related infections because there is anecdotal evidence to suggest that disease processes resulting from enteral feeding are still commonplace in the hospital and home. This is because there is very little information about the growth of microorganisms in ENS and whether growth in ENS may affect the virulence and pathogenicity of microorganisms. This study shows that Escherichia coli and Pseudomonas aeruginosa may grow at 25C from either high or low initial numbers to up to 9.2 log colony-forming units per mL in a range of milk-based ENS. However, these organisms did not grow in the fruit-based ENS. The effect on the lipopolysaccharide (LPS) of culturing E. coli and P. aeruginosa in milk-based ENS as opposed to standard laboratory media was examined using polyacrylamide gel electrophoresis. We found that there were significant qualitative changes in the phenotype of O-polysaccharide side chains of the LPS from these organisms. O-polysaccharide is known to mediate in the complement, antibiotic and bile resistance, and affect adherence. Therefore, changes in the virulence and pathogenicity of these microorganisms when cultured in ENS may be indicated. Thus, the study provides further evidence for reevaluating the microbiologic and immunologic effects of enteral feeding, especially on the microbial flora of the GI tract.
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    Inhibition of Listeria monocytogenes and Salmonella enteriditis by combinations of plant oils and derivatives of benzoic acid: the development of synergistic antimicrobial combinations.
    (International Society of Chemotherapy, 1998) Fyfe, Lorna; Armstrong, Fiona; Stewart, John
    This study describes inhibitory properties of combinations of oil of fennel, oil of anise or oil of basil with either benzoic acid or methyl-paraben against Listeria monocytogenes and Salmonella enteriditis. Micro-organisms were cultured at 37 degrees C in broth and viable counts measured over a 48-h period. S. enteriditis was particularly sensitive to inhibition by a combination of oil of anise, fennel or basil with methyl-paraben where there was < 10 CFU/ml after 1 h. L. monocytogenes was less sensitive to inhibition by each combination however there was a significant reduction in growth of 4-8 log by combinations of all oils and methyl-paraben at 8, 24 and 48 h. Synergistic inhibition by one or more combinations was evident against each micro-organism.
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    A review of the biological and potential therapeutic actions of harpagophytum procumbens
    (John Wiley & Sons, Ltd, 2007-11-24) McBean, Douglas; Grant, L.; Fyfe, Lorna; Warnock, Mary
    Harpagophytum procumbens (Hp), commonly known as Devil's Claw is a perennial plant which thrives in arid conditions. For centuries, it has been used as a traditional treatment for a variety of illnesses, including fevers, skin complaints, arthritis and diseases of the digestive tract as well as an appetite stimulant. Since its introduction to Europe in the early twentieth century, it has become a popular antiinflammatory and analgesic preparation amongst herbalists for supportive or adjuvant treatment of degenerative joint diseases, tendonitis, headache, backache and menstrual pain. The validity of Hp as an effective antiinflammatory and analgesic preparation, particularly in the relief of arthritic symptoms, has been investigated in numerous animal, clinical and in vitro studies. Although some contradictory evidence exists, the majority of animal studies appear to indicate Hp as an effective antiinflammatory and analgesic preparation in the treatment of acute and subacute inflammation. Clinical trials support Hp as a beneficial treatment for the alleviation of pain and improvement of mobility in a variety of musculoskeletal conditions. Analysis of the in vitro and ex vivo studies that currently exist, indicate that Hp has significant effects on numerous proinflammatory markers. However, the exact mechanism(s) by which Hp may reduce inflammation remain to be elucidated.
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    Influence of sub-inhibitory concentrations of plant essential oils on the production of enterotoxins A and B and alpha toxin by Staphylococcus aureus
    (Society for General Microbiology, 2004-10) Smith-Palmer, A.; Stewart, J.; Fyfe, Lorna
    The data presented show the ability of subinhibitory concentrations of plant essential oils to influence the production of enterotoxins A and B and alpha-toxin by Staphylococcus aureus. Subinhibitory concentrations of the oils of bay, clove, cinnamon, nutmeg and thyme had no significant effect on the overall quantity of extracellular protein produced. Haemolysis due to alpha-toxin was significantly reduced after culture with all five plant essential oils. This reduction was greatest with the oils of bay, cinnamon and clove. These three oils also significantly decreased the production of enterotoxin A; the oils of clove and cinnamon also significantly decreased the production of enterotoxin B.
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    The potential application of plant essential oils as natural food preservatives in soft cheese
    (Elsevier, 2001-08) Smith-Palmer, A.; Stewart, J.; Fyfe, Lorna
    Investigations were carried out to assess the efficiency of four plantessentialoils; bay, clove, cinnamon and thyme as naturalfoodpreservatives. The effect of the plantessentialoils at concentrations of 0·1, 0·5 and 1% was studied in low-fat and full-fat softcheese against Listeria monocytogenes and Salmonella enteritidis at 4° and 10°C respectively, over a 14-day period. The composition of the cheese was shown to be an important factor in determining the effectiveness of the plantessentialoils. In the low-fat cheese, all four oils at 1% reduced L. monocytogenes to ≤1·0 log10cfu ml−1. In contrast, in the full-fat cheese, oil of clove was the only oil to achieve this reduction. Oil of thyme proved ineffective against S. enteritidis in the full-fat cheese, yet was equally as effective as the other three oils in the low-fat cheese, reducing S. enteritidis to ≤1·0 log10cfu ml−1from day 4 onwards. It is concluded that selected plantessentialoils can act as potent inhibitors of L. monocytogenes and S. enteritidis in a food product.
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    Inhibition of listeriolypin O and phosphatidylcholine - specific phospholipase C production in Listeria monocytogeres by subinhibitory concentrations of plant essential oils
    (Society for General Microbiology, 2002-07) Smith-Palmer, A.; Stewart, J.; Fyfe, Lorna
    Successful infection by Listeria monocytogenes is dependent upon a range of bacterial extracellular proteins including a cytolysin termed listeriolysin O and phosphatidylcholine-specific phospholipase C. Five plant essential oils--bay, clove, cinnamon, nutmeg and thyme--significantly reduced the production of listeriolysin O by L. monocytogenes. The greatest change was observed after culture with oil of thyme, which reduced haemolysis to 52.1 haemolytic units (HU)/ml compared with 99.8 HU/ml observed with the control. Oil of clove was the only oil that also significantly reduced phosphatidylcholine-specific phospholipase C activity. These changes were observed despite the oils causing no change to the final bacterial concentration or total extracellular protein concentration.
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    Murine immune response to recombinant HIV1 p24 core protein following subcutaneous, intraperitoneal and intravenous immunisation
    (Wiley-Blackwell, 1991-11) Fyfe, Lorna; Maingay, J.; Robinson, A. C.; Howie, S. E.
    The murine immune response to baculovirus-produced human immunodeficiency virus type-1 (HIV-1)p24 was examined after injection by three different routes: subcutaneously (s.c.), intraperitoneally (i.p.) and intravenously (i.v.). Both antigen-specific T-cell proliferation and serum antibody were induced by i.p. injection. In contrast, s.c. and i.v. injection of antigen resulted in specific antibody generation alone. Lympho-proliferative responses seen after i.p. injection were confined to splenocytes, and were greater after a low dose of antigen than after a high dose. p24-specific proliferation was not detected in lymph node cells. CD4:CD8 ratios were normal in lymph nodes and spleen at all times, irrespective of the dose or route of administration. p24-specific serum IgG antibodies were detected in all animals after the second injection of antigen. After s.c. and i.v. administration of high doses of antigen, the median antibody titres continued to rise after a third injection, but plateaued in animals injected by the i.p. route. In contrast, low doses of antigen given i.p. increased the median titre during and after the course of four injections. A low antigen dose given s.c. resulted in a plateau of median titre between the third and fourth injections. In i.v.-injected animals the median titre decreased between the third and fourth injections. IgG1 p24-specific antibodies were detected in all immunized mice, whereas IgM antibodies were detectable only following i.p. injection of antigen.
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    Identification of major common extracellular proteins secreted by Aeromonas salmonicida strains isolated from diseased fish
    (1987-04-01) Fyfe, Lorna; Coleman, G.; Munro, A. L.
    Ten different strains of Aeromonas salmonicida that were isolated from diseased fish were grown under identical conditions (24 h at 25 degree C) in 3% (wt/vol) tryptone soya broth medium supplemented with vitamins and inorganic ions. In each case the extracellular proteins that were formed were compared by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and it was found that there were two significant common components, one with a molecular weight of 70,000 and the other with a weight of 56,000. Application of enzyme purification techniques to the supernatant fraction proteins of a culture of one of the strains resulted in the isolation of a 70-kilodalton (kDa) component, which was found to be a serine protease, and a 56-kDa component, which was hemolytic to trout erythrocytes. Rocket immunoelectrophoresis with rabbit antibodies to the isolated protease and hemolysin showed the same antigenic components in the supernatant fractions of all the cultures. These activities were assayed, and protease activity was found to vary by a factor of three, from 59 to 195 U/ml, while the range of hemolytic activity was over a narrow band, from 28 to 43 U/ml. There was an inconsistency between the immunoelectrophoretic and direct assay data in only one case. This indicated the presence of additional hemolytic activity, in addition to the 56-kDa component. The detection of large amounts of the same protease and hemolysin, two potent degradative activities, in a random series of strains of A. salmonicida suggests that they may be obligatory virulence factors in the development of furunculosis.