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- Bagge, Elisabeth
(författare)
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Hygiene aspects of the biogas process with emphasis on spore-forming bacteria
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Biogas is a renewable source of energy which can be obtained from processing of biowaste. The digested residues can be used as fertiliser. Biowaste intended for biogas production contains pathogenic micro-organisms. A pre-pasteurisation step at 70°C for 60 min before anaerobic digestion reduces non spore-forming bacteria such as Salmonella spp. To maintain the standard of the digested residues it must be handled in a strictly hygienic manner to avoid recontamination and re-growth of bacteria. The risk of contamination is particularly high when digested residues are transported in the same vehicles as the raw material. However, heat treatment at 70°C for 60 min will not reduce spore-forming bacteria such as Bacillus spp. and Clostridium spp. Spore-forming bacteria, including those that cause serious diseases, can be present in substrate intended for biogas production. The number of species and the quantity of Bacillus spp. and Clostridium spp. in manure, slaughterhouse waste and in samples from different stages during the biogas process were investigated. The number of species of clostridia seemed to decrease following digestion, likewise the quantity. However, Bacillus spp. seemed to pass unaffected through the biogas process. In laboratory-scale experiments the effects on clostridia during pasteurisation and digestion were investigated. Pathogenic clostridia were inoculated in substrates from homogenisation tanks and digester tanks. The inoculated clostridia remained after pasteurisation, but the impacts of digestion differ between different species. Culture followed by identification of C. chauvoei by PCR in samples from cattle died from blackleg, is faster and safer than culture followed by biochemical identification of C. chauvoei. However, for environmental samples the PCR method is not practically applicable for detection of C. chauvoei. To avoid spreading of diseases via biogas plants when digested residues are spread on arable land, a pasteurisation stage at 70°C for 60 min before anaerobic digestion gives adequate reduction of most non spore-forming bacteria, such as salmonella. However, caution should be exercised before digested residues are spread in areas without endemic problems of pathogenic spore-forming bacteria. In Sweden, official recommendation is that digested residues from biogas plants only should be applied on arable land, and not on grasslands for animal pasture.
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| 2. |
- Boqvist, Sofia, et al.
(författare)
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Experimental infection in calves with a specific subtype of verocytotoxin-producing Escherichia coli O157:H7 of bovine origin
- 2009
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Ingår i: Acta Veterinaria Scandinavica. - : Springer Science and Business Media LLC. - 0044-605X .- 1751-0147. ; 51
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Tidskriftsartikel (refereegranskat)abstract
- Conclusion: This study contributes with information concerning the dynamics of a specific subtype of VTEC O157:H7 colonisation in dairy calves. This subtype, VTEC O157:H7 (PT4;vtx(2);vtx(2c)), is frequently isolated from Swedish cattle and has also been found to cause the majority of reported human infections in Sweden during the past 15 years. In most calves, inoculated with a representative strain of this specific subtype, the numbers of shed bacteria declined over the first two weeks. One calf could possibly be classified as a high-shedder, excreting high levels of the bacterium for a prolonged period.
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| 3. |
- Durand, Caylib A, et al.
(författare)
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Phosphoinositide 3-kinase p110 delta regulates natural antibody production, marginal zone and B-1 B cell function, and autoantibody responses.
- 2009
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Ingår i: Journal of immunology (Baltimore, Md. : 1950). - : The American Association of Immunologists. - 1550-6606 .- 0022-1767. ; 183:9, s. 5673-84
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Tidskriftsartikel (refereegranskat)abstract
- B-1 and marginal zone (MZ) B cells produce natural Abs, make Ab responses to microbial pathogens, and contribute to autoimmunity. Although the delta isoform of the PI3K p110 catalytic subunit is essential for development of these innate-like B cells, its role in the localization, activation, and function of normal B-1 and MZ B cells is not known. Using IC87114, a highly selective inhibitor of p110delta enzymatic activity, we show that p110delta is important for murine B-1 and MZ B cells to respond to BCR clustering, the TLR ligands LPS and CpG DNA, and the chemoattractants CXCL13 and sphingosine 1-phosphate. In these innate-like B cells, p110delta activity mediates BCR-, TLR- and chemoattractant-induced activation of the Akt prosurvival kinase, chemoattractant-induced migration, and TLR-induced proliferation. Moreover, we found that TLR-stimulated Ab responses by B-1 and MZ B cells, as well as the localization of MZ B cells in the spleen, depend on p110delta activity. Finally, we show that the in vivo production of natural Abs requires p110delta and that p110delta inhibitors can reduce in vivo autoantibody responses. Thus, targeting p110delta may be a novel approach for regulating innate-like B cells and for treating Ab-mediated autoimmune diseases.
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| 4. |
- Ebrahimi, Majid, 1963-
(författare)
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Studies of p63 and p63 related proteins in patients diagnosed with oral lichen planus
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa and also one of the more common mucosal conditions mostly affecting middle aged individuals. Even though OLP is well investigated the etiology of this disease is still unknown, even if autoimmunity as a possible etiologic factor has been suggested. WHO classifies OLP as a pre malignant condition but malignant transformation of OLP is a matter of great controversy. The p53 protein is a tumour suppressor with the potential to induce apoptosis or cell cycle arrest of DNA damaged cells. Another member of the p53 family, p63, comprises six different isoforms, and plays a crucial role in the formation of oral mucosa, salivary glands, teeth and skin. p63 has also been suggested to be involved in development of squamous cell carcinoma of the head and neck (SCCHN). β-catenin, E-cadherin and epidermal growth factor receptor (EGFR) are p63 related proteins and abnormalities in their expression are suggested to be involved in development of SCCHN.Methods. Using immunohistochemistry and antibodies directed against p53 and those distinguishing between the p63 isoforms we analysed biopsies of OLP, SCCHN and normal oral tissue. We also mapped levels of p63 and p53 isoforms using RT-PCR technique. Furthermore expression of the p63 related proteins β-catenin, E-cadherin and EGFR was studied using immunoblot analysis. In an attempt to investigate autoimmunity as a causative factor of OLP we analysed sera from patients diagnosed with OLP and matched control individuals in order to see if there were autoantibodies directed against the p53 family.Results. When mapping p53 and p63 protein status decreased expression of p63 and increased expression of p53 was seen in OLP compared to normal tissue. In accordance with these results, levels of p63 RNA were also lower in OLP lesions compared with normal tissue. Concerning p53 isoforms, the “original” p53 isoform was expressed in all OLP lesions and normal control tissue. Of the other isoforms, p53β and Δ133p53 were expressed in the majority of samples. Our results regarding p63 related proteins showed a generally lower expression of these proteins in OLP lesions compared to normal control tissue. When studying sera from patients with OLP we found circulating autoantibodies against all six p63 and four p73 isoforms in two patients.Conclusions. The potential for malignant transformation of OLP is still a subject of discussion and rather controversial. While some of our results regarding status of p53 and p63 both at protein and RNA levels support this theory, other results concerning for example p63 related proteins point in the opposite direction. Based on our studies it is thus not possible to either support nor contradict the statement that OLP is a clear-cut premalignant condition. In our effort to understand the etiology of OLP we were the first to demonstrate autoantibodies against p63 and p73 in what could be a subgroup of OLP patients. OLP could thus be suggested to be not one distinct disease, but based on our data a disease comprising different subgroups.
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| 5. |
- Elving, Josefine
(författare)
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Pathogen inactivation and regrowth in organic waste during biological treatment
- 2009
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- After proper sanitation treatment, organic wastes such as animal by-products, e.g.catering waste, slaughterhouse waste and manure can be used as fertilisers and soil conditioners and thereby contribute to a sustainable society. However, organic waste may contain pathogenic microorganisms and can thus present a health risk to both humans and animals if not properly treated. In the present thesis regrowth potential of Salmonella Typhimurium, Enterococcus spp. and coliforms in organic waste at psychrophilic and mesophilic temperatures and the time and temperature combinations required for pathogen inactivation during thermal treatments was investigated. This was done with the aim to contribute to hygienically safe recycling of organic waste. Pathogen growth was observed in active compost material as well as in fresh cattle manure. The growth potential decreased with increased maturity of the compost. In thermal treatment of fresh cattle manure, a treatment temperature of 52°C and a retention time of 17.2 h or a temperature of 55°C during 16.9 h were needed to achieve the reduction targets set by current EU regulation in terms of bacterial reduction. However, this time and temperature combination was not sufficient to achieve the reduction target of 3 log10 for parvovirus as a thermoresistant virus. The inactivation rate of Salmonella Senftenberg W775 and Enterococcus spp. were found to increase with increased moisture content whereas the opposite relationship between inactivation rate and moisture content was observed for viruses.
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| 6. |
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| 9. |
- Guo, Yongzhi, 1972-
(författare)
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Plasmin : a potent pro-inflammatory factor
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Plasmin, the central molecule of the plasminogen activator system, is a broad-spectrum serine protease. Plasmin is important for the degradation of fibrin and other components of the extracellular matrix (ECM) during a number of physiological and pathological processes. The aim of this thesis was to elucidate the functional roles of plasmin during pathological inflammation and infection in autoimmune and non-autoimmune diseases. For this purpose, mouse models of rheumatoid arthritis (RA), bacterial arthritis, infection, and sepsis have been used. Previous studies from our laboratory have shown that plasminogen-deficient mice are resistant to the development of collagen type II-induced arthritis (CIA). In contrast, others have shown that plasmin plays a protective role in antigen-induced arthritis (AIA). To investigate the contrasting roles of plasminogen deficiency in models of CIA and AIA, a new animal model of arthritis called local injection-induced arthritis (LIA) was developed. In this model, we replaced methylated bovine serum albumin, which is normally used as an immunogen in the AIA model, with collagen type II (CII) to induce arthritis. When wild-type and plasminogen-deficient mice were injected intra-articularly with CII or 0.9% NaCl following CIA induction, plasminogen-deficient mice developed typical CIA, but the disease was less severe than in wild-type mice and was restricted to the injected joints. When the AIA model was used, plasminogen-deficient mice developed a much more severe arthritis than the wild-type mice. These results indicate that both the antigen and joint trauma caused by the local injection are critical to explaining the contrasting roles of plasminogen deficiency in CIA and AIA. This indicates that CIA and AIA have distinct pathogenic mechanisms and plasmin plays contrasting roles in different types of arthritis models. To study the functional roles of plasmin in the host inflammatory response during infectious arthritis, a Staphylococcus aureus-induced bacterial arthritis model was established. When wild-type mice were injected intra-articularly with 1 × 106 colony-forming units (CFU) of S. aureus per joint, all the bacteria were completely eliminated from the injected joints in 28 days. However, in the plasminogen-deficient mice, the S. aureus counts were 27-fold higher at day 28 than at day 0. When human plasminogen was given to the plasminogen-deficient mice daily for 7 days, the bacterial clearance was greatly improved and the necrotic tissue in the joint cavity was also completely eliminated. Supplementation of plasminogen-deficient mice with plasminogen also restored the expression level of interleukin-6 (IL-6) in the arthritic joints. In summary, plasmin has protective roles during S. aureus-induced arthritis by enhancing cytokine expression, removing necrotic tissue, and mediating bacterial killing and inflammatory cell activation. The functional roles of plasmin during infection and sepsis were also studied in mice. Infection was induced by injecting 1 × 107 CFU of S. aureus intravenously and the sepsis model was induced by injecting 1.6 × 108 CFU of S. aureus. In the infection model, the wild-type mice had a 25-day survival rate of 86.7%, as compared to 50% in the plasminogen-deficient group. However, when sepsis was induced, the average survival for plasminogen-deficient mice was 3 days longer than for wild-type mice. Twenty-four hours after the induction of sepsis, the serum levels of IL-6 and IL-10 as well as the bacterial counts in all organs investigated were significantly higher in wild-type mice than in plasminogen-deficient mice. In wild-type mice, blockade of IL-6 by intravenous injection of anti-IL-6 antibodies significantly prolonged the onset of mortality and improved the survival rate during sepsis. These data indicate that plasmin plays different roles during infection and sepsis. Furthermore, plasmin appears to be involved in the regulation of inflammatory cytokine expression during sepsis. Taken together, our data indicate that plasmin plays multifunctional pro-inflammatory roles in different autoimmune and non-autoimmune diseases. The pro-inflammatory roles of plasmin include activation of inflammatory cells, regulation of cytokine expression, and enhancement of the bacterial killing ability of the host.
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| 10. |
- Hammarsten, Peter, 1977-
(författare)
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Androgen controlled regulatory systems in prostate cancer : potential new therapeutic targets and prognostic markers
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- BACKGROUND: Prostate cancer is by far the most common cancer among Swedish men. Some patients have an aggressive lethal disease, but the majority of affected men have long expected survival. Unfortunately, the diagnostic tools available are insufficient in predicting disease aggressiveness. Novel prognostic markers are therefore urgently needed. Furthermore, metastatic prostate cancer is generally treated with castration, but the long-term effects are insufficient. Additional studies are therefore needed to explore how the effects of this therapy can be enhanced. Prostate growth and regression is beside testosterone controlled by locally produced regulators. Vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) are two of the major regulators in the normal prostate and in prostate tumours. MATERIALS AND METHODS: VEGF and EGFR were explored in the prostate, by treating rats with either anti-VEGF or anti-EGFR treatment during castration and testosterone-stimulated prostate growth. Rats with implanted androgen-independent prostate tumours were treated with an inhibitor of both VEGF receptor-2 (VEGFR-2) and EGFR. Stereological techniques, immunohistochemistry, western blotting and quantitative real-time PCR were used to evaluate these experiments. Furthermore, prostate tissue from untreated prostate cancer patients was used to retrospectively explore the expression of phosphorylated-EGFR (pEGFR) in relation to outcome. RESULTS: Anti-VEGF treatment during testosterone-stimulated prostate growth, inhibited vascular and prostate growth. Anti-EGFR treatment during castration and testosterone-stimulated prostate growth resulted in enhanced castration effects and inhibited prostate growth. Anti-vascular treatment of androgen-independent prostate cancer with an inhibitor of VEGFR-2 and EGFR, that targets the normal and tumour vasculature, enhanced the effects of castration. Low immunoreactivity for pEGFR in prostate epithelial cells, both in the tumour and also in the surrounding non-malignant tissue, was associated with good prognosis. CONCLUSIONS: Anti-vascular treatment, with an inhibitor of VEGFR-2 and EGFR, in combination with castration could be an effective way to treat androgen-insensitive prostate tumours. VEGF and EGFR signalling are necessary components in testosterone-stimulated prostate growth. Phosphorylation of EGFR could be a useful prognostic marker for prostate cancer patients. Tumours may affect the surrounding non-malignant tissue and pEGFR immunoreactivity in the morphologically normal prostate tissue can be used to retrieve prognostic information.
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