| 1. |
- Almkvist, Jenny, 1971, et al.
(författare)
-
Lipopolysaccharide-induced gelatinase granule mobilization primes neutrophils for activation by galectin-3 and formylmethionyl-Leu-Phe.
- 2001
-
Ingår i: Infection and immunity. - 0019-9567 .- 1098-5522. ; 69:2, s. 832-7
-
Tidskriftsartikel (refereegranskat)abstract
- We have earlier shown that galectin-3, a lactose-binding mammalian lectin that is secreted from activated macrophages, basophils, and mast cells, induces activation of the NADPH oxidase in exudated but not in peripheral blood neutrophils (A. Karlsson, P. Follin, H. Leffler, and C. Dahlgren, Blood 91:3430-3438, 1998). The alteration in responsiveness occurring during extravasation correlated with mobilization of the gelatinase and/or specific granules to the cell surface, indicating a role for mobilizable galectin-3 receptors. In this study we have investigated galectin-3-induced NADPH oxidase activation, measured as superoxide production, in lipopolysaccharide (LPS)-primed neutrophils. Upon galectin-3 challenge, the LPS-primed cells produced superoxide, both extracellularly and intracellularly. A primed extracellular response to formylmethionyl-Leu-Phe (fMLF) was also achieved. The exposure of complement receptors 1 and 3 as well as the formyl peptide receptor on the cell surface was markedly increased after LPS treatment, indicating that granule fusion with the plasma membrane had occurred. Further assessment of specific markers for neutrophil granules showed that the LPS treatment had mobilized the gelatinase granules but only a minor fraction of the specific granules. We thus suggest that the mechanism behind LPS priming lies at the level of granule (receptor) mobilization for galectin-3 as well as for fMLF.
|
|
| 2. |
- John, Sternbeck, et al.
(författare)
-
Screening of organotin compounds in theSwedish environment
- 2006
-
Rapport (övrigt vetenskapligt/konstnärligt)abstract
- A number of organotin compounds are used in the society, but the knowledge ontheir environmental impact is mainly restricted to those compounds that are used inantifouling paints on ships. In this screening study, the occurrence of butyltins, octyltins, phenyltins and tricyclohexyltin in the Swedish environment was investigated. The sampling programme was setup based on the use of organotins in nonbiocidal applications. There is an emphasis on the lacustrine environment in threeurban regions, but the study also covers sewage treatment plants, an agricultural field, a plastics industry, landfills, foodstuffs and breastmilk. A total of 107 sampleswere analysed. Furthermore, the physical-chemical and toxicological properties oforganotins are briefly summarised and their use in the Swedish society is described.The major goals were to assess‰ If diffuse release of organotins occurs in urban areas‰ If releases of organotins from municipal sewage treatment plants (STPs) influence the levels in the aquatic environment‰ If industrial use may cause a local impact of organotins‰ If the use of sewage sludge as a fertiliser causes organotin accumulation insoils‰ If human exposure is significantBecause this is a screening study, some of these goals had to be assessed on the basis of few samples, whereas other aspects could be more thoroughly investigated.Urban stormwater sludge from three cities shows that diffuse releases of monobutyltin, dibutyltin, tributyltin, monoctyltin and dioctyltin occur in urban areas. This diffuse release is also evident in the aquatic environment, where in particular DBT andMBT are enriched in urban sediments. The relative abundance of organotin compounds is very similar in urban stormwater sludge and sewage sludge, suggestingcommon sources. Furthermore, the specific load to municipal STPs (µg/d/pe) is similar to earlier results from households, suggesting that diffuse releases from products in the urban environment is important.STPs appear to influence the levels of MBT in their recipients moderately, but noother organotin compound is released in significant quantities by these STPs. Theconcentrations in stormwater sludge and soil close to a PVC industry suggest thatemissions may occur from the current industrial use of butyltins and octyltins.Fish from various lakes and the Baltic Sea contain butyltins and phenyltins. Whenconsidering the occurrence of these substances in sediments, and their present use, itappears that phenyltins are more strongly accumulated than butyltins in fish. Perchfrom Mälaren, Stockholm city and the Stockholm archipelago contains higher levelsof dibutyltin, tributyltin and triphenyltin than fish from other lakes. The levels inStockholm city is particularly high.In conclusion, there was a good correspondence between the type of organotin compounds found in the present study and those that are used in the society. Phenyltinsmainly occured in the aquatic environment in areas where large ships travel. Octyltins were found in waste waters and sludge, in urban stormwaters and in certainurban sediments, suggesting an association to products containing octyltins. Butyltins were found in all these environments, in agreement with their use both in themarine environment and in urban areas.
|
|
| 3. |
- Almquist, Ann-Charlotte, et al.
(författare)
-
Host selection in Tomicus piniperda L. : Composition of monoterpene hydrocarbons in relation to attack frequency in the shoot feeding phase
- 2006
-
Ingår i: Zeitschrift fur Naturforschung - Section C Journal of Biosciences. - : Walter de Gruyter GmbH. - 0939-5075. ; 61:5-6, s. 439-444
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to investigate the host selection capacity of the pine shoot beetle, Tomicus piniperda, in the shoot-feeding phase and analyze the chiral and non-chiral host volatiles by means of GC-MS and 2D-GC in five Pinus species originating from France (Pinus sylvestris, P. halepensis, P. nigra laricio, P. pinaster maritima, P. pinaster mesogeensis). Dominating monoterpenes were (-)-α-pinene, (+)-α-pinene, (-)-β-pinene and (+)-3-carene. The amounts of the enantiomers varied considerably within and among the species. In a principal component analysis-plot, based on the absolute amounts of 18 monoterpene hydrocarbons, separation of the pine species into two groups was obtained. P. halepensis and P. sylvestris were grouped according to the amount of (+)-α-pinene and (+)-3-carene, while P. nigra laricio, P. pinaster maritima and P. pinaster mesogeensis were grouped according to (-)-α-pinene and (-)-β-pinene. P. nigra laricio was the species most attacked and P. halepensis the one least attacked by T. piniperda.
|
|
| 4. |
- Caous, Josefin Seth, 1982, et al.
(författare)
-
Adhesion of Streptococcus mitis and Actinomyces oris in co-culture to machined and anodized titanium surfaces as affected by atmosphere and pH
- 2013
-
Ingår i: BMC Oral Health. - : Springer Science and Business Media LLC. - 1472-6831. ; 13:4
-
Tidskriftsartikel (refereegranskat)abstract
- BackgroundWith the rising demand for osseointegrated titanium implants for replacing missing teeth, often in patients with a history of periodontitis, implant-related infections have become an issue of growing concern. Novel methods for treating and preventing implant-associated infections are urgently needed. The aim of this study was to investigate if different pH, atmosphere and surface properties could restrict bacterial adhesion to titanium surfaces used in dental implants.MethodsTitanium discs with machined or anodized (TiUnite™) surface were incubated with a co-culture of Streptococcus mitis and Actinomyces oris (early colonizers of oral surfaces) at pH 5.0, 7.0 and 9.0 at aerobic or anaerobic atmosphere. The adhesion was analysed by counting colony forming (CFU) units on agar and by confocal laser scanning microscopy (CLSM).ResultsThe CFU analysis showed that a pH of 5.0 was found to significantly decrease the adhesion of S. mitis, and an aerobic atmosphere, the adhesion of A. oris. S. mitis was found in significantly less amounts on the anodized surface than the machined surface, while A. oris was found in equal amounts on both surfaces. The CLSM analysis confirmed the results from the CFU count and provided additional information on how the two oral commensal species adhered to the surfaces: mainly in dispersed clusters oriented with the groves of the machined surface and the pores of the anodized surface.ConclusionsBacterial adhesion by S. mitis and A. oris can be restricted by acidic pH and aerobic atmosphere. The anodized surface reduced the adhesion of S. mitis compared to the machined surface; while A. oris adhered equally well to the pores of the anodized surface and to the grooves of the machined surface. It is difficult to transfer these results directly into a clinical situation. However, it is worth further investigating these findings from an in vitro perspective, as well as clinically, to gain more knowledge of the effects acid pH and aerobic atmosphere have on initial bacterial adhesion.
|
|
| 5. |
- Fäldt, Jenny, 1971, et al.
(författare)
-
Activation of human neutrophils by mycobacterial phenolic glycolipids.
- 1999
-
Ingår i: Clinical and experimental immunology. - 0009-9104. ; 118:2, s. 253-60
-
Tidskriftsartikel (refereegranskat)abstract
- The interaction between mycobacterial phenolic glycolipids (PGLs) and phagocytes was studied. Human neutrophils were allowed to interact with each of four purified mycobacterial PGLs and the neutrophil production of reactive oxygen metabolites was followed kinetically by luminol-/isoluminol-amplified chemiluminescence. The PGLs from Mycobacterium tuberculosis and Mycobacterium kansasii, respectively, were shown to stimulate the production of oxygen metabolites, while PGLs from Mycobacterium marinum and Mycobacterium bovis BCG, respectively, were unable to induce an oxidative response. Periodate treatment of the M. tuberculosis PGL decreased the production of oxygen radicals, showing the importance of the PGL carbohydrate moiety for the interaction. The activation, however, could not be inhibited by rhamnose or fucose, indicating a complex interaction which probably involves more than one saccharide unit. This is in line with the fact that the activating PGLs from M. tuberculosis and M. kansasii contain tri- and tetrasaccharides, respectively, while the nonactivating PGLs from M. marinum and M. bovis BCG each contain a monosaccharide. The complement receptor 3 (CR3) has earlier been shown to be of importance for the phagocyte binding of mycobacteria, but did not appear to be involved in the activation of neutrophils by PGLs. The subcellular localization of the reactive oxygen metabolites formed was related to the way in which the glycolipids were presented to the cells.
|
|
| 6. |
- Fäldt, Jenny, 1971
(författare)
-
Activation of neutrophils by mycobacteria and mycobacterial components
- 2001
-
Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The genus Mycobacterium includes free-living saprophytes, opportunists, and human pathogens.Mycobacterium tuberculosis, the organism causing tuberculosis, as well as other pathogenicmycobacteria can survive and multiply inside phagocytic cells, but the underlying mechanisms areonly partly understood. The innate immune response to mycobacterial infections is predominantlymediated and regulated by activated macrophages. Neutrophils are, however, an important part of thefirst-line of defence against most microorganisms. Protection is achieved either by direct killing of thebacteria or through production of cytokines. The neutrophils might therefor be important also in thedefence against mycobacteria.The aim of this study was to investigate the neutrophil responses induced by cell wall componentsand whole cells representing mycobacteria that differ concerning virulence. The study was focused onthe capability of mycobacterial cell wall structures or whole mycobacteria cells to induce an oxidativeresponse and production of cytokines.Phenolic glycolipids (PGLs) from M. kansasii and M. tuberculosis induced an oxidative responsein human neutrophils, which PGLs from M. marinum and M. bovis BCG were unable to do. Thecarbohydrate part was shown to be of crucial importance for the interaction. In contrast, the cell wallcomponent lipoarabinomannan (LAM) was unable to bring about a significant oxidative response inneutrophils, but induced a primed state in the cells. The primed state was accompanied by granulemobilisation, shown as an increased exposure of receptors as well as a release of granule contents.Neutrophils were also exposed to whole living mycobacterial cells and it was shown that M.tuberculosis, the opportunistic M. avium, and the non-pathogenic M. smegmatis all induced aproduction/release of TNF-a, IL-6, and IL-8 from human neutrophils. The amounts induced by M.tuberculosis were, however, lower than for the other non-pathogenic bacteria. The inefficientinduction of these cytokines in neutrophils could be a mechanism for the tubercle bacilli to persist,while the non-pathogenic mycobacteria are effectively eliminated.In conclusion, mycobacteria and mycobacterial components do affects neutrophils. The oxygenradicals produced and the cytokines released might be important parts in the early defence againstmycobacterial infections.
|
|
| 7. |
- Fäldt, Jenny, 1971, et al.
(författare)
-
Priming of human neutrophils by mycobacterial lipoarabinomannans: role of granule mobilisation.
- 2001
-
Ingår i: Microbes and infection. - 1286-4579. ; 3:13, s. 1101-9
-
Tidskriftsartikel (refereegranskat)abstract
- Lipoarabinomannans (LAMs) from mycobacteria were investigated concerning their effect on human neutrophils. Two types of LAM, the mannose-capped ManLAM from the virulent Mycobacterium tuberculosis H37Rv and the mannose-lacking AraLAM from a rapidly growing mycobacterial strain were used. Neither AraLAM nor ManLAM induced any significant direct activation of the NADPH-oxidase. Both LAMs, however, primed the neutrophils so that subsequent stimulation with the peptide chemoattractants fMet-Leu-Phe (fMLF), Trp-Lys-Tyr-Met-Val-DMet (WKYMVm) and the mammalian lactose-binding lectin galectin-3 resulted in a markedly enhanced oxidative response. The LAM-induced priming was accompanied by an increased exposure of complement receptors 1 and 3 as well as the formyl peptide receptor on the neutrophil surface, suggesting that the enhanced oxidative response could be due to upregulation of receptors on the cell surface as a result of granule mobilisation. Since LAM-primed neutrophils released 65% of the cell content of gelatinase but showed no increased release of vitamin B(12)-binding protein, mobilisation of the gelatinase granules rather than the specific granules is concluded to be responsible for the priming effects. This is in agreement with the subcellular localisation of receptors for fMLF, WKYMVm, as well as galectin-3, which are stored in the secretory vesicles and gelatinase granules. The priming effect appeared very similar to that of Escherichia coli lipopolysaccharide, and since no differences in activity could be detected between AraLAM and ManLAM, we hypothesize that the lipid anchor of the LAM is responsible for the priming effects.
|
|
| 8. |
- Fäldt, Jenny, 1971, et al.
(författare)
-
Reduced exercise endurance in interleukin-6-deficient mice
- 2004
-
Ingår i: Endocrinology. - 0013-7227. ; 145:6, s. 2680-6
-
Tidskriftsartikel (refereegranskat)abstract
- IL-6 is produced and released in large amounts from skeletal muscle during prolonged exercise in both mice and humans, but there are few data indicating the biological significance of this. IL-6 exerts metabolic effects such as stimulating energy expenditure and reducing body fat mass. We have now investigated the effects of IL-6 deficiency on exercise endurance and energy expenditure in preobese and obese IL-6-deficient (IL-6(-/-)) mice. Four-month-old preobese and 7-month-old obese IL-6(-/-) male mice backcrossed to C57BL/6 and their littermate controls were exercised on a treadmill, and energy expenditure was measured as oxygen consumption with the use of indirect calorimetry. The preobese IL-6(-/-) mice were significantly leaner than the control mice, whereas the older IL-6(-/-) mice, as expected, had developed obesity. Resting young, but not older, IL-6(-/-) mice had an elevated respiratory exchange ratio (RER), indicating that they oxidize carbohydrates rather than fat for energy utilization. During exercise, the young and older IL-6(-/-) mice had a reduced endurance and a progressive decrease in oxygen consumption compared with control mice. There was no difference in RER in young IL-6(-/-) mice, whereas RER was enhanced in older IL-6(-/-), mice during exercise. In summary, IL-6(-/-) mice have reduced endurance and energy expenditure during exercise, suggesting that IL-6 is necessary for normal exercise capacity.
|
|
| 9. |
- Fäldt, Jenny, 1971, et al.
(författare)
-
The phagocyte chemiluminescence paradox: luminol can act as an inhibitor of neutrophil NADPH-oxidase activity.
- 1999
-
Ingår i: Luminescence : the journal of biological and chemical luminescence. - 1522-7235. ; 14:3, s. 153-60
-
Tidskriftsartikel (refereegranskat)abstract
- The chemiluminescence system amplified by luminol or isoluminol is a sensitive and widely used method for determination of respiratory burst products generated by the NADPH-oxidase in phagocytes. The present study shows that luminol, but not isoluminol, can inhibit the release of oxygen metabolites generated by human neutrophil NADPH-oxidase. The difference in structure between luminol and isoluminol (rendering luminol more lipophilic than isoluminol, and thereby membrane-permeable), is suggested to determine indirectly whether or not the molecule is inhibitory. Luminol was shown to have an increased inhibitory effect after preincubation of neutrophils on a surface of aggregated IgG, suggesting that the cells can be transferred from a 'luminol-insensitive' to a 'luminol-sensitive' state. Since luminol had no inhibitory effect in a cell-free NADPH-oxidase system, it is likely that it interferes with the signal transduction pathway, leading to assembly and/or activation of the oxidase. As a consequence of the present results, showing that luminol but not isoluminol can inhibit NADPH-oxidase activity, we suggest that isoluminol is used in future studies of superoxide anion release from phagocytes.
|
|
| 10. |
|
|
