| 1. |
- Apelkvist, Björn
(författare)
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Vad är bildning?
- 2003
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Ingår i: Horisont. - 0439-5530. ; :2
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Tidskriftsartikel (populärvet., debatt m.m.)
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| 2. |
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| 3. |
- Kinhult, Sara
(författare)
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Endothelial and cardiac effects of 5-fluorouracil. An experimental and clinical study.
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The cytostatic drug 5-fluorouracil (5-FU) has been shown to affect both morphology and function of vascular endothelium. These effects could be part of the pathophysiology for 5-FU induced cardiotoxicity. The present thesis explores the mechanisms of this endothelial toxicity. In an animal model, treatment with thromboprophylactic doses of the low-molecular weight heparin (LMWH) dalteparin could not protect the endothelium from damage caused by 5-FU, although the secondary thrombosis was prevented. A subsequent study with three different LMWH (dalteparin, enoxaparin and tinzaparin) showed a moderate endothelial injury after treatment with LMWH alone for up to 60 days. Probucol, a lipid-lowering drug with strong antioxidant properties, was given as prophylaxis for two weeks before 5-FU treatment. With this drug, the endothelium was protected from the negative effects of 5-FU and had a normal morphology. Patients receiving 5-days infusion of 5-FU, combined with cisplatin, were studied for endothelial and cardiac effects. There was a significant increase in markers for endothelial injury (von Willebrand factor and soluble thrombomodulin) and in malondialdehyde, a marker for increased lipoperoxidation and possibly free radical production. Myocardial and echocardiographic parameters were not changed. Human umbilical vein endothelial cells (HUVEC) were incubated with 5-FU. A dose-dependant increase in secretion of endothelin-1 (a potent vasoconstrictor) was shown. No influence of apoptosis was seen. The results indicate increased oxidative stress caused by 5-FU, followed by endothelial damage and secretion of a vasoactive peptide. This could be part of the pathophysiological mechanisms of 5-FU induced cardiotoxicity.
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| 4. |
- Nasizadeh, Sima
(författare)
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A Study on Trypanosomal Polyamine Biosynthetic Enzymes
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The polyamines, putrescine, spermidine, and spermine, are essential for all forms of life. The polyamine biosynthetic pathway has been shown to be a potential target for drugs against various trypanosomal parasitic diseases. The two main enzymes in the biosynthesis of polyamines are ornithine decarboxylase (ODC) and S-adenosylmethionine decarboxylase (AdoMetDC). ODC catalyzes the first step of polyamine biosynthesis. Mammalian ODC is tightly regulated by polyamines and has a very fast turnover rate. The degradation of this enzyme is 26S proteasome dependent, but ubiquitin independent. The polyamines induce the degradation of mammalian ODC by stimulating the synthesis of a protein termed antizyme, which binds to and targets the enzyme for degradation by the 26S proteasome. Most trypanosomal ODCs, e.g. Leishmania donovani ODC and Trypanosoma brucei ODC are metabolically stable, but, interestingly, Crithidia fasciculata ODC has a fast turnover. In this thesis, the mechanisms involved in the rapid turnover of C. fasciculata ODC are examined. The degradation of C. fasciculata ODC was shown to be rapid also in mammalian systems, whereas that of L. donovani ODC was not. The rapid turnover of the enzyme was markedly reduced by inhibition of the 26S proteasome, indicating the involvement of this proteolytic system in the degradation of C. fasciculata ODC. However, unlike the mammalian ODC, C. fasciculata ODC was not down-regulated by polyamines, suggesting an antizyme independent degradation mechanism. As a result of analyzing the turnover of a series of chimeric ODCs between C. fasciculata ODC and L. donovani ODC, it was found that the central part of the former enzyme is important for its rapid degradation. The characterization of C. fasciculata AdoMetDC, the other main polyamine biosynthetic enzyme, revealed that also this enzyme has an extremely fast turnover (ca 3 min). Furthermore, no polyamine-mediated feedback regulation of AdoMetDC was observed in the parasite. As an alternative to using polyamine biosynthesis inhibitors, CHO cells expressing the trypanosomal ODCs were used to analyze the effects of different polyamine pools on cell cycle progression. It was shown that CHO cells expressing L. donovani ODC had a reduced polyamine synthesis, resulting in a decrease in cellular putrescine and spermidine levels (compared to wild-type CHO cells). On the other hand, the spermine content was increased. The changes in polyamine content were reflected in changes in cell growth kinetics.
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| 5. |
- Eriksson Linsmeier, Cecilia
(författare)
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Neuronal and glial differentiation of expanded neural stem and progenitor cells; in vitro and after transplantation.
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis we have used cells dissected from the lateral ganglionic eminence (LGE), the medial ganglionic eminence (MGE), and the cortical primordium of the embryonic mouse forebrain. The tissue was dissected from either i) wild-type mice, ii) green fluorescent protein (GFP)-, or iii) Gtv-a-expressing transgenic mice, and subsequently grown and expanded in vitro using two different protocols. Cells were either plated and extensively expanded as attached glial cultures in the presence of epidermal growth factor (EGF) and serum, or expanded in the presence of EGF and basic fibroblast growth factor (bFGF) as free-floating aggregates termed neurospheres. The attached LGE-derived cells were expanded for more that 7 months (25 passages), and the cells expressed neural stem-/progenitor markers, such as glial fibrillary acidic protein (GFAP), nestin, RC2 and M2/M6, both at early and late passages. We demonstrated that the repeatedly passaged attached glial cultures derived from either the LGE or MGE (but not the cortical primordium) were capable of generating significant numbers of neurons and glial cells at differentiating conditions, i.e. after removal of EGF and serum from the expansion medium. By using a transgenic approach, we were able to show that at least a subset of the newly generated neurons and oligodendrocytes were derived from GFAP-expressing cells. Interestingly, the newly generated neurons were found to retain some of their region-specific expression even after extensive in vitro-expansion. After grafting of the expanded attached LGE-derived cells, we found that they were able to integrate into both the adult (intact and lesioned) and neonatal rat striatum, as visualized with the mouse-specific astroglial marker M2. However, even though these cells had the capacity to differentiate into neurons and glial cells in vitro, we were only able to detect few neuron-like cells after transplantation. Instead these cells expressed almost exclusively an astroglial phenotype after implantation. Moreover, we showed that cells from expanded neurosphere cultures, derived from the LGE, MGE and cortical primordium of the embryonic GFP-transgenic mouse, had the capacity to differentiate into morphologically fully mature neurons, as well as astrocytes and oligodendrocytes after transplantation, as visualized with the species-specific marker M2 and the reporter gene GFP. These results demonstrated the ability of mouse derived neural stem-/progenitor cells expanded in vitro as neurospheres to generate both neurons and glia after transplantation into neonatal recipients, and differentiate into mature neurons with morphological features characteristic for each target site. Altogether, the results of the present thesis demonstrate a capacity of cells derived from the mouse embryonic forebrain to be long-term expanded using two different protocols, and that the cells have the potential to differentiate in vitro and give rise to progeny with at least some region-specific characteristics retained. The cells can also survive and integrate into the host tissue after transplantation. However, mainly cells grown as neurospheres displayed the potential of neuronal differentiation after implantation into the neonatal graft host. A lot of experimental work is still needed in order to understand and control the mechanisms for growth and differentiation of neural stem-/progenitor cells before such cells can be applied in other studies, such as in clinical trials towards treatment of for example neurodegenerative disorders.
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| 6. |
- Kinhult, Johan
(författare)
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PACAP and airway regulation with special reference to smooth muscle and neutrophils
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The investigations focus on the neuropeptidepituitary adenylate cyclase-activating peptide and its effects on airway regulation, with emphasis on smooth muscle relaxation and neutrophil activation and migration. In the nasal mucosa, PACAP-containing nerve fibers were localized invascular smooth muscle and close to seromucous glands. In the lung, PACAP-containing nerve fibers were found close to seromucous glands and in smooth muscle layers of bronchi, as well as in the wall of pulmonary arteries. PACAP caused a concentration-dependent relaxation of precontracted human bronchial and pulmonary arterial segments. VIP (Vasoactive intestinal peptide), also present in the human lung, failed to relax the majority of the bronchial segments tested. In guinea pig, the carbon monoxide (CO) producing enzyme heme oxygenase (HO) was observed in airway smooth muscle bundles. PACAP-containing nerve fibers were localized in association with the same structures as HO. In addition, PACAP relaxed precontracted guinea pig tracheal segments via a CO-dependent mechanism, indicating a role for CO in PACAP-induced airway relaxation. Following activation, certain glycoproteins, like CD11b, CD66b and CD63, emanating from intracellular granules, can be expressed on the neutrophil cell surface. An increase in the expression of CD11b, CD66b and CD63 was found following the migration of neutrophils from the blood stream to the surface of the nasal mucosa, indicating the presence of activated neutrophils in the nose. During ongoing allergic rhinitis, the expression of CD11b on neutrophils derived from the nose was further increased suggesting augmented neutrophil activation. In contrast neutrophils from the blood exhibited a reduced expression of CD11b and CD66b. The latter might be a reflection of negative feedback mechanisms. Human neutrophils incubated with PACAP exhibited a marked increase in their surface expression of CD11b, CD66b and CD63. No such increases were found following incubation with VIP. In contrast, both peptides inhibited N-formylmethionyl-leucyl-phenylalanine (fMLP)-induced neutrophil chemotaxis. Application of PACAP in the human nose increased nasal airway resistance and augmented the increase in nasal resistance induced by histamine. In addition, PACAP inhibited histamine induced recruitment of neutrophils, increased plasma leakage and reduced the level of IL-1RA (an endogenously produced interleukin-1 receptor antagonist) in nasal lavage fluid. Altogether, the data presented in this thesis support the idea of PACAP as a modulator within the human airways, with a potential role in inflammatory diseases like allergy and asthma.
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| 7. |
- Nihlén, Ulf
(författare)
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Chronic Obstructive Pulmonary Disease (COPD) Epidemiological and Pan-airway Aspects
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background – Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide. However, there is little information on the prevalence and particularly on the incidence of COPD. Also, apart from the importance of tobacco smoking and a1-antitrypsin deficiency, information on contributing risk factors for the development of COPD is limited. Hypotheses – 1. Spirometry can be used in primary health care settings to improve diagnosis of COPD. 2. Alcohol intake is associated with COPD. 3. Coronary heart disease (CHD) is common in patients with COPD. 4. A family history of COPD is an independent risk factor for development of COPD. 5. Specific nasal symptoms and nasal symptom-provoking exposures can predict the development of COPD. 6. The nasal mucosa in COPD may feature a specific pathology. Methods – Studies focusing on spirometry assessments, analysis of a marker of alcohol intake (serum carbohydrate deficient transferrin: S-CDT), and register studies (the Swedish Survey on Living Conditions (ULF) linked with the Swedish Inpatient register), as well as respiratory questionnaire surveys were employed. Also, a nasal lavage study comprising histamine-challenges and analysis of markers of neutrophil activity (myeloperoxidase), plasma exudation and secretory/mucinous activity (fucose) was carried out. Results – Spirometry detected many new cases of COPD. A majority of them were unaware of their condition. The prevalence of COPD was 11.5% and 4.5% as assessed by spirometry and questionnaires, respectively. The annual incidence of COPD as assessed by questionnaires (1992 and 2000, respectively) was 0.36%. S-CDT was elevated in COPD and inversely correlated to FEV1. Report of alcohol intake according to the ULF interview in 1988/89 predicted a higher risk of a hospitalisation for COPD from the time point of the ULF interview to the end of 2000. A hospitalisation for CHD during this time was also associated with an increased risk of COPD hospitalisation. A family history of COPD predicted the incidence of a self-reported physician’s diagnosis of COPD. “Thick, yellow discharge” and “a blocked nose”, as well as the nasal symptom provoking factors “damp/cold air” and “tobacco exposure”, also predicted this incidence. Also, an association was observed between self-reported COPD and the incidence of a physician’s diagnosis of nasal polyposis. The difference in myeloperoxidase between a histamine and saline lavage was greater in patients with COPD than in healthy subjects. Furthermore, COPD-patients reporting nasal symptoms presented increased levels of myeloperoxidase at histamine challenge (c.f. saline) and greater differences in myeloperoxidase and fucose, respectively, between the histamine and saline lavage (c.f. patients without symptoms). Conclusions –The prevalence as well as the incidence of COPD in Sweden is high. Underdiagnosis of COPD is considerable and spirometry should be considered in all smokers. High alcohol consumption and CHD may be associated with an increased risk for being hospitalised due to COPD. A family history of COPD and distinct nasal features may be risk factors for the development of COPD. COPD is not associated with any marked nasal inflammation, but nasal pathology may need attention in this condition.
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| 8. |
- Ohlsson, Sophie
(författare)
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The Balance between Pro- and Antiinflammatory Molecules in ANCA-Associated Vasculitis
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- ANCA-associated systemic vasculitis (AASV) is a group of inflammatory disorders, characterized by inflammation and necrosis of blood vessels and frequently granuloma formation. Patients with AASV make autoantibodies, so called ANCA, against proteins present in the granules of neutrophils and monocytes, mainly proteinase 3 (PR3) and myeloperoxidase (MPO). Clinically, disease progression is characterized by a relapsing-remitting course. Although remitting in nature, disease flares can lead to permanent organ damage or even death. Moreover, the standard therapy of today, high-dose corticosteroids and cyclophospahamide, is associated with severe side effects like bladder cancer and severe infections and although effective in inducing remission, the relapse rates are high. The pathogenesis is still unknown and the importance of ANCA debated. In this thesis some fundamental aspects, like gene expression of the ANCA antigens and status of immune activation have been addressed. The main findings are those of a PR3-expression in circulating monocytes, 9-fold higher in our patients than in the controls, together with deranged circulating cytokine pattern. Most interestingly, these findings are present in patients who are in complete clinical remission, indicating some kind of basic defect in the immune system. A disability to resolve inflammatory processes would eventually lead to self-perpetuating grumbling activity, held back by local protease inhibitors like SLPI and inhibitory cytokines like IL-10. This would create a borderline environment, making it easy for some sort of unknown trigger, such as a virus or another environmental factor, to elicit a full blown inflammatory response. ANCA could, if present, probably fuel this process by interacting with antigens expressed on the surface of neutrophils and monocytes. Besides the pathogenic aspects, some of the results might have clinical implications. IL-6 seems to be a potential marker of imminent relapse and should be thoroughly evaluated as such in a larger patient study over a longer time period. IL-8, on the other hand, might be a prognostic marker, considering the strong association with impending organ damage. The finding of low IL-10 levels being associated with relapse tendency of course evokes interest in exploring its therapeutic potential.
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| 9. |
- Olanders, Knut
(författare)
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Intestinal ischemia and reperfusion. Proinflammatory response and organ dysfunction
- 2003
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Intestinal I/R is considered to be an important initiating event in several pathophysiological conditions such as trauma, bleeding, sepsis and pancreatitis, frequently leading to concomitant both single and potentially multiple organ dysfunction. The purpose of this thesis was to study mechanims underlying the development of multiple organ dysfunction, with special focus on intercellular proinflammatory regulation in the concurrent development of tissue injury. A further aim was to evaluate novel forms of therapy and prevention against the development of multipel organ dysfunction. Experimental intestinal I/R was induced by clamping the superior mesenteric artery in male Sprague-Dawley rats for 40 min, followed by reperfusion up to 12 hrs. Treatment attempts with N-Acetylcystein (NAC), the platelet activating factor (PAF) inhibitor lexipafant, monoclonal antibodies (MAbs) against platelet endothelial cell adhesion molecule-1 (PECAM-1), active-site-inactivated FVIIa (FVIIai) or the FXa inhibitor fondaparinux were tested. It was found that intestinal I/R induced an increase in intercellular adhesion molecule-1 (ICAM-1) expression in different tissues with marked organ variability. In parallel, an inflammatory response with neutrophil recruitment in the lungs and intestines as well as an increased endothelial barrier permeability in several organs was observed. Inflammatory mediators such as TNF-a, IL-1b, MCP-1 and MIP-2 also increased, with an earlier response in organs directly affected by the I/R-injury than in organs more distantly located. Treatment 15 min after the start of reperfusion with NAC and lexipafant attenuated the inflammatory response, but did not affect the ICAM-1 expression, suggesting that the protective effects of NAC and PAF-inhibition is not mediated via decreased expression of ICAM-1. Therapy inserted at 3 hrs of reperfusion, also decreased the inflammatory response and tissue injury, although not as pronounced as demonstrated after early treatment. Administration of the anticoagulants FVIIai or fondaparinux resulted in decreased plasma levels of the neutrophil chemoattractant MIP-2, whereas only FVIIai restored endothelial barrier dysfunction and decreased intestinal neutrophil recruitment. This demonstrates that inhibition of the TF-FVIIai complex formation by FVIIai can attenuate inflammatory responses in connection with intestinal I/R. Based on our results, we suggest that a multimodal treatment regime with inhibitors against inflammatory mediators such as oxygen free radicals, platelet activating factor and coagulation factors such as FVIIa and FXa, could represent potential future strategies in the prevention and treatment of organ dysfunction in hyperinflammatory states, seen e.g. in association with critical illness.
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