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| 2. |
- Asif, Sana, M.D, PhD student, et al.
(författare)
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Validation of an MPC polymer coating to attenuate surface- induced cross-talk between the complement and coagulation systems in whole blood in in vitro and in vivo models
- 2019
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Ingår i: Macromolecular Bioscience. - : Wiley-VCH Verlagsgesellschaft. - 1616-5187 .- 1616-5195. ; 19:5
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Tidskriftsartikel (refereegranskat)abstract
- Artificial surfaces that come into contact with blood induce an immediate activation of the cascade systems of the blood, leading to a thrombotic and/or inflammatory response that can eventually cause damage to the biomaterial or the patient, or to both. Heparin coating has been used to improve hemocompatibility, and another approach is 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer coatings. Here, the aim is to evaluate the hemocompatibility of MPC polymer coating by studying the interactions with coagulation and complement systems using human blood in vitro model and pig in vivo model. The stability of the coatings is investigated in vitro and MPC polymer-coated catheters are tested in vivo by insertion into the external jugular vein of pigs to monitor the catheters' antithrombotic properties. There is no significant activation of platelets or of the coagulation and complement systems in the MPC polymer-coated one, which was superior in hemocompatibility to non-coated matrix surfaces. The protective effect of the MPC polymer coat does not decline after incubation in human plasma for up to 2 weeks. With MPC polymer-coated catheters, it is possible to easily draw blood from pig for 4 days in contrast to the case for non-coated catheters, in which substantial clotting is seen.
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| 3. |
- Asif, Sana, M.D, PhD student, et al.
(författare)
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Validation of an MPC polymer coating to reduce surface-induced cascade system activation in whole blood in in vitroand in vivo models
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- ABSTRACTBackground: Artificial surfaces that come into contact with blood (e.g., when used in various forms of biomedical device) induce an immediate activation of the cascade systems of the blood, the coagulation and complement systems. These reactions may lead to a thrombotic and/or inflammatory response that can eventually cause damage to the biomaterial or the patient, or to both. Multiple strategies to dampen these reactions have been employed, with heparin conjugation to the material surface being the most successfulthus far. Another approach to improving hemocompatibility is to use 2-methacryloyloxyethyl phosphorylcholine (MPC)-based polymer coatings.Experimental: In the present study, we evaluated the effectiveness of MPC polymer coating and compared it to a commercially available heparin coating in various in vitromodels using fresh human blood with the aim to replace the costly heparin-coated equipment with the more economic MPC. We then investigated the stability of the various coatings in human plasma in vitrofor 2 weeks. Finally, we inserted MPC polymer-coated catheters into the external jugular vein of pigs and monitored the catheters’ antithrombotic properties for 4 days.Results: 1) There was no significant activation of platelets and of the coagulation and complement systems on the MPC polymer-coated or the commercially available heparin surface. 2) Both coats were superior in hemocompatibility to non-coated matrix surfaces. 3) The protective effect of the MPC polymer coat did not decline after incubation in plasma for up to 2 weeks. 4) With MPC polymer-coated catheters, it was possible to easily draw blood from experimental animals for 4 days, in contrast to the case for heparin-flushed commercially available non-coated catheters, in which substantial clotting was seen.
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| 4. |
- Axelsson, Linn, 1977-
(författare)
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Making Borders : Engaging the threat of Chinese textiles in Ghana
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The borders of the twenty-first century come in many forms and are performed by an increasing number of actors in a broad variety of places, both within and beyond the territories of nation-states. This thesis sets out a detailed political geography of how borders operate to reconcile the often conflicting demands of open markets and security. Focusing on Ghana, where there is a widespread fear that the inflow of Chinese versions of African prints will lead to the collapse of the local textile industry, the study explores where and when borders are enforced, who performs them and what kinds of borders are enacted in order to maintain and protect the Ghanaian nation and market without compromising the country’s status as a liberal economy. It combines interviews and documentary sources with analysis drawn from border, security and migration studies to explore three sets of spatial strategies that have defined the Ghanaian approach to the perceived threat of Chinese African prints. They are the institution of a single corridor for African print imports, the anti-counterfeiting raids carried out in Ghana’s marketplaces, and the promotion of garments made from locally produced textiles as office wear through the National Friday Wear and Everyday Wear programmes. These strategies stretch, disperse and embody the borders of the state or nation to control trade in ways that resolve the fears of both open flows and closed borders. This thesis thus seeks to show how a geographical analysis can clarify the specificities of how borders now work to control mobility. In doing so, it not only unsettles conventional assumptions about what borders are and where they are supposed to be located, but also the idea that borders primarily are used to constrain the mobility of certain people while facilitating economic flows. Furthermore, this thesis adds to the understanding of the variety of responses to the inflow of Chinese consumer products to the African continent.
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| 6. |
- Kullman, Eric, et al.
(författare)
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Covered versus uncovered self-expandable nitinol stents in the palliative treatment of malignant distal biliary obstruction: results from a randomized, multicenter study
- 2010
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Ingår i: GASTROINTESTINAL ENDOSCOPY. - : Elsevier Science B. V., Amsterdam. - 0016-5107 .- 1097-6779. ; 72:5, s. 915-923
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Tidskriftsartikel (refereegranskat)abstract
- Background: Covered biliary metal stents have been developed to prevent tumor ingrowth. Previous comparative studies are limited and often include few patients. Objective: To compare differences in stent patency, patient survival, and complication rates between covered and uncovered nitinol stents in patients with malignant biliary obstruction. Design: Randomized, multicenter trial conducted between January 2006 and October 2008. Setting: Ten sites serving a total catchment area of approximately 2.8 million inhabitants. Patients: A total of 400 patients with unresectable distal malignant biliary obstruction. Interventions: ERCP with insertion of covered or uncovered metal stent. Follow-up conducted monthly for symptoms indicating stent obstruction. Main Outcome Measurements: Time to stent failure, survival time, and complication rate. Results: The patient survival times were 116 days (interquartile range 242 days) and 174 days (interquartile range 284 days) in the covered and uncovered stent groups, respectively (P = .320). The first quartile stent patency time was 154 days in the covered stent group and 199 days in the uncovered stent group (P = .326). There was no difference in the incidence of pancreatitis or cholecystitis between the 2 groups. Stent migration occurred in 6 patients (3%) in the covered group and in no patients in the uncovered group (P = .030). Limitations: Randomization was not blinded. Conclusions: There were no significant differences in stent patency time, patient survival time, or complication rates between covered and uncovered nitinol metal stents in the palliative treatment of malignant distal biliary obstruction. However, covered stents migrated significantly more often compared with uncovered stents, and tumor ingrowth was more frequent in uncovered stents.
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| 8. |
- Lindell, Fredrik, et al.
(författare)
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Prosthetic valve endocarditis caused by Propionibacterium species: a national registry-based study of 51 Swedish cases
- 2018
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Ingår i: European Journal of Clinical Microbiology & Infectious Diseases. - : Springer Science and Business Media LLC. - 0934-9723 .- 1435-4373. ; 37:4, s. 765-771
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Tidskriftsartikel (refereegranskat)abstract
- Propionibacterium spp. are a rare cause of infective endocarditis (IE). The diagnosis is difficult because the bacteria are slow-growing and growth in blood cultures is often misinterpreted as contamination from the skin flora. The aim of this study was to describe all cases of Propionibacterium spp. endocarditis in the Swedish national registry of IE. The registry was searched for all cases of IE from 1995 to 2016 caused by Propionibacterium spp. Data concerning clinical characteristics, treatment, and outcome were registered. A total of 51 episodes of definitive prosthetic valve endocarditis (PVE) caused by Propionibacterium spp. were identified, comprising 8% of cases of PVE during the study period. Almost all cases (n = 50) were male. The median time from surgery to diagnosis of IE was 3 years. Most patients were treated mainly with beta-lactams, partly in combination with aminoglycosides. Benzyl-penicillin was the most frequently used beta-lactam. A total of 32 patients (63%) underwent surgery. Overall, 47 patients (92.1%) were cured, 3 (5.9%) suffered relapse, and 1 (2.0%) died during treatment. IE caused by Propionibacterium spp. almost exclusively affects men with a prosthetic valve and findings of Propionibacterium spp. in blood cultures in such patients favors suspicion of a possible diagnosis of IE. In patients with prosthetic valves, prolonged incubation of blood cultures up to 14 days is recommended. The prognosis was favorable, although a majority of patients required cardiac surgery during treatment. Benzyl-penicillin should be the first-line antibiotic treatment option for IE caused by Propionibacterium spp.
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| 9. |
- Lindell, Åke
(författare)
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Clinical studies on cystinuria : With special reference to treatment with tiopronin
- 1996
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Cystinuria is an inherited disorder of the renal tubular transport of cystine and the dibasic amino acids across cell membranes. Defective renal tubular reabsorption causes a greatly increased urinary excretion of thepoorly soluble cystine, which in turn results in the formation of renal stones. Because of the life-long tendency for stone formation the patients are highly susceptible to complications of renal stone disease. Urinary supersaturation of cystine can be counteracted by reducing the urinary concentration (increased fluid intake, chemical modification with a sulfhydryl compound) or by increasing its solubility (urinary alkalinization). Long-tenn treatment with the sulfhydryl compound tiopronin (2-mercaptopropionylglycine) was evaluated in 31 patients with homozygous cystinuria (Papers I, II, IV). The patients were followed over an average of 7.8 years and the treatment was monitored by regular measurements of cystine in 24-hour urine samples by ionexch: mge chromatography, and by X-ray examinations. In 40 cystimnic patients total and split kidney function were investigated by gamma camera renography and measurement of glomerular filtration rate (GFR), mainly51CR-EDTA-clearance (Paper Ill). The diurnal variations in urinary cystine excretion was studied in 8 patients (Paper VI), and the effect of a low sodium intake in 13 (Paper V). A urinary free cystine concentration below the assumed level of saturation of 1200 J..Lmol/1 in 24h urine samples was achieved in 90% of patients treated with tiopronin. The required doses varied from 500 to 3000 mg!day which illustrates the necessity for individualization of treatment by regular measurements of the urinary cystine concentration. Increasing doses of tiopronin resulted in an unexpected decrease in the urinary excretion of the soluble tiopronin-cysteine mixed disulphide suggesting an influence on the general metabolism of cystine and cysteine. The rate of new stone· formation wa<> reduced by 60% and the need for active stone removal by 72%. Stone fonnation was eliminated in two thirds of the patients. In the remaining third there was some formation ofrenal stones in spite of acceptable concentrations of cystine in 24h samples. This shows that also the therapeutic level of urinary cystine has to be individually adjusted in some patients. Measurements of cystine in6h samples in patients without tiopronin treatment revealed considerable variations with peak concentration exceeding the corresponding 24h concentration by as mUch as 91%. Fractionated urine sampling may therefore be a tool for further adjustment of therapy. Treatment with tiopronin was well tolerated by the majority of patients, and the finding of clinically reversible membranous glomerulonephritis in 3 patients does not disqualify the drug from further use. Thirty per cent of 40 patients had light to moderate impainnent of renal function. Only 28% had an entirely normal renal function with both GFR and renography within nonnallimits, but there was no case with severe renal impairment. A renographic comparison between the pre-treatment and treatment periods suggested that the stone-preventing treatment based on monitoring of urinary cystine concentration resulted in preservation of renal function. Restriction of sodium intake resulted in a decrease in urinary cystine excretion in patients without tiopronin treatment, whereas the effect was significantly less in patients with tiopronin. In the patients without tiopronin the sodium delivery conveyed by sodium bicarbonate treatment neutralized the increased solubility of cystine obtained by its alkalinizing effect. The excretion of the disulphide between tiopronin and cysteine wasalso sodium dependent suggesting an active tubular reabsorption of this compound.
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