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- Berg, A. Håkan, et al.
(författare)
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Biochemical characterization of the Arctic char (Salvelinus alpinus) ovarian progestin membrane receptor
- 2005
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Ingår i: Reproductive Biology and Endocrinology. - : Springer Science and Business Media LLC. - 1477-7827. ; 3, s. 64-
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Tidskriftsartikel (refereegranskat)abstract
- Membrane progestin receptors are involved in oocyte maturation in teleosts. However, the maturation-inducing steroid (MIS) does not appear to be conserved among species and several progestins may fulfill this function. So far, complete biochemical characterization has only been performed on a few species. In the present study we have characterized the membrane progestin receptor in Arctic char (Salvelinus alpinus) and show that the 17,20beta-dihydroxy-4-pregnen-3-one (17,20beta-P) receptor also binds several xenobiotics, thus rendering oocyte maturation sensitive to environmental pollutants. We identified a single class of high affinity (Kd, 13.8 +/- 1.1 nM), low capacity (Bmax, 1.6 +/- 0.6 pmol/g ovary) binding sites by saturation and Scatchard analyses. Receptor binding displayed rapid association and dissociation kinetics typical of steroid membrane receptors, with t1/2 s of less than 1 minute. The 17,20beta-P binding also displayed tissue specificity with high, saturable, and specific 17,20beta-P binding detected in ovaries, heart and gills while no specific binding was observed in muscle, brain or liver. Changes in 17,20beta-P binding during oocyte maturation were consistent with its identity as the oocyte MIS membrane receptor. Incubation of fully-grown ovarian follicles with gonadotropin induced oocyte maturation, which was accompanied by a five-fold increase in 17,20beta-P receptor binding. In addition, competition studies with a variety of steroids revealed that receptor binding is highly specific for 17,20beta-P, the likely maturation-inducing steroid (MIS) in Arctic char. The relative-binding affinities of all the other progestogens and steroids tested were less than 5% of that of 17,20beta-P for the receptor. Several ortho, para derivatives of DDT also showed weak binding affinity for the 17,20beta-P receptor supporting the hypothesis that xenobiotics may bind steroid receptors on the oocyte's surface and might thereby interfere with oocyte growth and maturation.
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- Berg, Håkan, et al.
(författare)
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17beta-estradiol induced vitellogenesis is inhibited by cortisol at the post-transcriptional level in Arctic char (Salvelinus alpinus)
- 2004
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Ingår i: Reproductive Biology and Endocrinology. - : Springer Science and Business Media LLC. - 1477-7827. ; 2, s. 62-
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Tidskriftsartikel (refereegranskat)abstract
- This study was performed to investigate stress effects on the synthesis of egg yolk precursor, vitellogenin (Vtg) in Arctic char (Salvelinus alpinus). In particular the effect of cortisol (F) was determined since this stress hormone has been suggested to interfere with vitellogenesis and is upregulated during sexual maturation in teleosts. Arctic char Vtg was purified and polyclonal antibodies were produced in order to develop tools to study regulation of vitellogenesis. The Vtg antibodies were used to develop an enzyme-linked immunosorbent assay. The corresponding Vtg cDNA was cloned from a hepatic cDNA library in order to obtain DNA probes to measure Vtg mRNA expression. Analysis of plasma from juvenile Arctic char, of both sexes, exposed to different steroids showed that production of Vtg was induced in a dose dependent fashion by 17beta-estradiol (E2), estrone and estriol. Apart from estrogens a high dose of F also upregulated Vtg. In addition, F, progesterone (P) and tamoxifen were tested to determine these compounds ability to modulate E2 induced Vtg synthesis at both the mRNA and protein level. Tamoxifen was found to inhibit E2 induced Vtg mRNA and protein upregulation. P did not alter the Vtg induction while F reduced the Vtg protein levels without affecting the Vtg mRNA levels. Furthermore the inhibition of Vtg protein was found to be dose dependent. Thus, the inhibitory effect of F on Vtg appears to be mediated at the post-transcriptional level.
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- Berg, Håkan, et al.
(författare)
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Characterization of antibodies for quantitative determination of spiggin protein levels in male and female three-spined stickleback (Gasterosteus aculeatus)
- 2009
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Ingår i: Reproductive Biology and Endocrinology. - : BioMed Central (BMC). - 1477-7827. ; 7:1
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Tidskriftsartikel (refereegranskat)abstract
- Spiggin is an adhesive glycoprotein produced in the kidney of sticklebacks during the breeding season and is subsequently secreted into the urinary bladder from where it is employed for nest building. Since the production of the protein has been shown to be under androgenic control, spiggin has been suggested to be a useful biomarker for androgenic substances in the environment. In this study, two polyclonal spiggin antibodies based on synthetic peptides and one polyclonal antibody directed against native spiggin have been characterized. The antibodies ability to identify spiggin was investigated by quantitative immunoassay. For both peptide antibodies the quantification range was determined to be between 1 and 80 ng spiggin and determination of renal spiggin levels from immature and mature males displayed a 15-fold increase in total spiggin content of the kidney resulting in a 6-fold increase in male kidney weight due to hypertrophy. The kidney somatic index (KSI) was found to correlate well with the total renal spiggin content and therefore it appears that KSI in sticklebacks could be used as an initial method to identify substances displaying androgenic effects. Furthermore, western blot analysis revealed that the polyclonal antibodies recognize different spiggin isoforms and that spiggin can be detected in the urinary bladder and kidney of both males and female sticklebacks. In order to develop a quantitative detection method for native spiggin it is necessary to produce a standard that can be used in a bioassay. Due to the adhesive and polymerization characteristics of spiggin the protein is difficult to use as a standard in bioassays. So far spiggin has been shown to exist in at least 14 isoforms, all of which contain polymerization domains. To overcome the solubility problem we have produced recombinant spiggin gamma, with only one polymerization domain, that can be expressed in E. coli. Western blot analysis demonstrated that the polyclonal antibodies were able to detect recombinant spiggin gamma protein in bacterial cell lysate, suggesting that it may be developed into a useful source of standard spiggin to be used for quantitative determination of androgen induced spiggin production in sticklebacks.
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- Brundin, Pia, 1974-
(författare)
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Politics on the net : NGO practices and experiences
- 2008
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- This study investigates how different kinds of non-governmental organisations (NGOs), operating in different national political contexts, perceive and use the Internet as a political space. The political space concept, as defined here, encompasses two dimensions of Internet use: one external, where organisations use the Internet for online activism and campaigning, and one internal, signifying organisational use of the Internet to promote engagement and interactivity with members and/or supporters. Another question raised is whether Internet use for political purposes by NGOs varies between different national political contexts. Moreover, do the organisations believe that the Internet has affected their political influence to any extent? The empirical data consist of the results of two surveys, one directed primarily to American NGOs, the other explicitly comparative, analysing NGOs in Sweden and the USA. Furthermore, content analyses of NGO websites have been conducted and additive indexes constructed. The findings of the study suggest that, overall, the Internet is most important to the studied organisations as a space for external political initiatives. There were, however, important differences in this regard, which could be related to the organisations’ national political contexts. For example, the American NGOs have oriented their websites primarily towards relatively superficial forms of member involvement, while the Swedish NGOs provided more interactive grassroots features on their websites. Regarding political influence, the Internet arguably has the potential to make the most dramatic difference by reinforcing the organisations’ offline political activities. The present results indicate that, despite the possible converging effect of the Internet on NGO political activism, national political culture exerts an inescapable influence on how the Internet is used as a political space by the studied organisations.
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| 7. |
- Caspillo, Nasim Reyhanian, 1982-
(författare)
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Hitting the mark : studies of alterations in behaviour and fertility in ethinyl estradiol-exposed zebrafish and search related biomarkers
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- In this thesis, we have analysed the effects of EE2 on non-reproductive behaviours and fertility. We have showed that two doses of EE2 in male adult short-term exposures evokes opposite behaviours in the novel tank test. A lower dose induced increased bottom-dwelling, a sign of increased anxiety and a higher dose increased surface-dwelling, which would likely expose themselves to predation in a natural environment. Increased shoaling was observed in both exposures, possibly affecting feeding and reproduction opportunities. Fertility analysis of these fish demonstrated a complete inhibition of spawning in the highest dose group. To investigate mechanisms behind the spawning failure, we examined expression levels of genes involved in zebrafish sex differentiation and maintenance of gonadal function. We found downregulated transcription levels of male-predominant genes, suggesting a demasculinization of the testes contributing to functional sterility in these fish. We have demonstrated that non-reproductive behaviour in zebrafish is highly sensitive to EE2 exposure during development. After exposing male and female zebrafish to low doses of EE2 followed by remediation in clean water until adulthood, the fish displayed increased anxiety and shoaling behaviour, demonstrating persistent effects of EE2. Furthermore, behavioural effects were transferred to their progeny. Decreased fertilisation success of the developmentally exposed fish was observed in both sexes when mated to untreated animals of the opposite sex. These fertility effects persisted although the fish had a long remediation period, implying likely reduced fitness of fish populations in aquatic environments. Based on our findings on non-reproductive behaviours and fertility, we performed RNAsequencing analysis of the brain and testes in order to investigate possible biological mechanisms behind the persistent effects. There is a need for biomarkers allowing detection of both reversible and irreversible effects in animals exposed to estrogenic substances, hopefully contributing to better risk assessments for EDCs. Results from RNA-sequencing would serve as a basis for continued studies in pursuit of potential biomarkers.
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| 8. |
- Elmarghani, Ahmed, 1975-, et al.
(författare)
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Contribution of pharmaceuticals, fecal bacteria and endotoxin to the inflammatory responses to inland waters
- 2014
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Ingår i: Science of the Total Environment. - : Elsevier. - 0048-9697 .- 1879-1026. ; 488-489, s. 228-235
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Tidskriftsartikel (refereegranskat)abstract
- The increasing contamination of freshwater with pharmaceuticals, surfactants, pesticides and other organic compounds are of major concern. As these contaminants are detected at trace levels in the environment it is important to determine if they elicit biological responses at the observed levels. In addition to chemical pollutants, there is also a concern for increasing levels of bacteria and other microorganisms in freshwater systems. In an earlier study, we observed the activation of inflammatory systems downstream of a wastewater treatment plant (WWTP) in southern Sweden. We also observed that the water contained unidentified components that were pro-inflammatory and potentiated the immune response in human urinary bladder epithelial cells. In order to determine if these effects were unique for the studied site or represent a common response in Swedish water, we have now performed a study on three WWTPs and their recipient waters in central Sweden. Analysis of immune responses in urinary bladder epithelial cells, monocyte-like cells and blood mononuclear cells confirm that these waters activate the immune system as well as induce pro-inflammatory responses. The results indicate that the cytokine profiles correlate to the endotoxin load of the waters rather than to the levels of pharmaceuticals or culturable bacteria load, suggesting that measurements of endotoxin levels and immune responses would be a valuable addition to the analysis of inland waters.
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| 9. |
- Gavali, Hamid, et al.
(författare)
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Outcome of Radical Surgical Treatment of Abdominal Aortic Graft and Endograft Infections Comparing Extra-anatomic Bypass with In Situ Reconstruction : A Nationwide Multicentre Study
- 2021
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Saunders Elsevier. - 1078-5884 .- 1532-2165. ; 62:6, s. 918-926
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Abdominal aortic graft and endograft infection (AGI) is primarily treated by resection of the infected graft and restoration of distal perfusion through extra-anatomic bypass (EAB) or in situ reconstruction/repair (ISR). The aim of this study was to compare these surgical strategies in a nationwide multicentre retrospective cohort study.Methods: The Swedish Vascular Registry (Swedvasc) was used to identify surgically treated abdominal AGIs in Sweden between January 1995 and May 2017. The primary aim was to compare short and long term survival, as well as complications for EAB and ISR.Results: Some 126 radically surgically treated AGI patients were identified – 102 graft infections and 24 endograft infections – treated by EAB: 71 and ISR: 55 (23 neo-aorto-iliac systems, NAISs). No differences in early 30 day (EAB 81.7% vs. ISR 76.4%, p =.46), or long term five year survival (48.2% vs. 49.9%, p =.87) were identified. There was no survival difference comparing NAIS to other ISR strategies. The frequency of recurrent graft infection during follow up was similar: EAB 20.3% vs. ISR 17.0% (p =.56). Survival and re-infection rates of the new conduit did not differ between NAIS and other ISR strategies. Age ≥ 75 years (odds ratio [OR] 4.0, confidence interval [CI] 1.1 – 14.8), coronary artery disease (OR 4.2, CI 1.2 – 15.1) and post-operative circulatory complications (OR 5.2, CI 1.2 – 22.5) were associated with early death. Prolonged antimicrobial therapy (> 3 months) was associated with reduced long term mortality (HR 0.3, CI 0.1 – 0.9).Conclusion: In this nationwide multicentre study comparing outcomes of radically treated AGI, no differences in survival or re-infection rate could be identified comparing EAB and ISR.
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| 10. |
- Gavali, Hamid, et al.
(författare)
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Semi-Conservative Treatment Versus Surgery in Abdominal Aortic Graft and Endograft Infections
- 2023
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Elsevier. - 1078-5884 .- 1532-2165. ; 66:3, s. 397-406
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Abdominal aortic graft and endograft infections (AGIs) are rare complications following aortic surgery. Radical surgery (RS) with resection of the infected graft and reconstruction with extra-anatomical bypass or in situ reconstruction is the preferred therapy. For patients unfit for RS, a semi-conservative (SC), graft-preserving strategy is possible. This paper aimed to compare survival and infection outcomes between RS and SC treatment for AGI in a nationwide cohort.METHODS: Patients with abdominal AGI-related surgery in Sweden between January 1995 and May 2017 were identified. The Management of Aortic Graft Infection Collaboration (MAGIC) criteria were used for definition of AGI. Multivariable regression was performed to identify factors associated with mortality.RESULTS: A total of 169 patients with surgically treated abdominal AGI were identified, comprising 43 SC [14 endografts; 53% with a graft-enteric fistula (GEF) in total] and 126 RS [26 endografts; 50% with a GEF in total]. The SC cohort was older and had a higher frequency of cardiac comorbidities. There was a non-significant trend towards lower Kaplan-Meier estimated 5-year survival for SC versus RS (30.2% vs. 48.4%; p = .066). A non-significant trend was identified towards worse Kaplan-Meier estimated 5-year survival for SC patients with a GEF versus without a GEF (21.7% vs. 40.1%; p = .097). There were significantly more recurrent graft infections comparing SC versus RS (45.4% vs. 19.3%; p < .001). In a Cox regression model adjusting for confounders, there was no difference in 5-year survival comparing SC versus RS (HR 1.0, 95% CI 0.6 - 1.5).CONCLUSION: In this national AGI cohort, we could not identify any mortality difference comparing SC versus RS for AGI when adjusting for comorbidities. Presence of GEF likely negatively impacts survival outcomes of SC patients. Rates of recurrent infection remain high for SC-treated patients.
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