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- Ahlsson, Anders, 1962-, et al.
(författare)
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A Swedish consensus on the surgical treatment of concomitant atrial fibrillation
- 2012
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Ingår i: Scandinavian Cardiovascular Journal. - London, United Kingdom : Informa Healthcare. - 1401-7431 .- 1651-2006. ; 46:4, s. 212-218
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Forskningsöversikt (refereegranskat)abstract
- Atrial fibrillation (AF) is a common arrhythmia among patients scheduled for open heart surgery and is associated with increased morbidity and mortality. According to international guidelines, symptomatic and selected asymptomatic patients should be offered concomitant surgical AF ablation in conjunction with valvular or coronary surgery. The gold standard in AF surgery is the Cox Maze III ("cut-and-sew") procedure, with surgical incisions in both atria according to a specified pattern, in order to prevent AF reentry circuits from developing. Over 90% of patients treated with the Cox Maze III procedure are free of AF after 1 year. Recent developments in ablation technology have introduced several energy sources capable of creating nonconducting atrial wall lesions. In addition, simplified lesion patterns have been suggested, but results with these techniques have been unsatisfactory. There is a clear need for standardization in AF surgery. The Swedish Arrhythmia Surgery Group, represented by surgeons from all Swedish units for cardiothoracic surgery, has therefore reached a consensus on surgical treatment of concomitant AF. This consensus emphasizes adherence to the lesion pattern in the Cox Maze III procedure and the use of biatrial lesions in nonparoxysmal AF.
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| 2. |
- Ahlsson, Anders, 1962-, et al.
(författare)
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Kirurgisk behandling av förmaksflimmer i samband med hjärtkirurgi [Surgical treatment of atrial fibrillation in connection with cardiac surgery] : konsensusrapport från Sveriges arytmiansvariga hjärtkirurger [Consensus report from Swedish cardiac surgeons responsible for arrhythmia]
- 2012
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Ingår i: Läkartidningen. - Stockholm : Läkartidningen Förlag AB. - 0023-7205 .- 1652-7518. ; 109:5, s. 214-217
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Tidskriftsartikel (refereegranskat)abstract
- Förmaksflimmer är vanligt och förekommer hos 6–10 procent av de patienter som ska genomgå kranskärlsoperation eller klaffkirurgi. Kirurgisk ablation av förmaksflimmer i samband med kranskärlsoperation eller klaffkirurgi bör erbjudas alla symtomatiska och utvalda asymtomatiska patienter. Cox-maze III (labyrintoperation) är den metod som gett bäst resultat vad avser frihet från förmaksflimmer 1 år efter ingreppet.Under senare år har flera nya metoder utvecklats för att åstadkomma elektriskt isolerande lesioner i hjärtats förmak. Dessa är tekniskt enklare och mindre invasiva. De är dock behäftade med sämre resultat än den ursprungliga Cox-maze III-operationen. Arytmiansvariga kirurger på landets samtliga hjärtkirurgiska kliniker har nått samstämmighet om hur förmaksflimmer bör behandlas i samband med annan hjärtkirurgi. Denna konsensus, vilken presenteras här, betonar vikten av att vid kirurgisk ablation följa lesionsmönstret i Cox-maze III och helst behandla både höger och vänster förmak för bästa långtidsresultat.
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| 5. |
- Andersson, Marcus, 1975, et al.
(författare)
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Effect of molecular mobility of polymeric implants on soft tissue reactions: An in vivo study in rats
- 2008
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Ingår i: Journal of Biomedical Materials Research Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 84A:3, s. 652-660
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Tidskriftsartikel (refereegranskat)abstract
- Although numerous different polymers are used as implants or otherwise studied for many other biotechnical applications, there is a lack of basic models that correlate polymer characteristics with foreign body reactions. This study aims at developing one such model by systematically studying surface molecular mobility of polymeric implants in soft tissues in vivo. Changing the length of the alkyl side chain of poly(alkyl methacrylates) (PAMAs), provides an interesting opportunity to study the surface molecular mobility with minimal changes of the hydrophobicity of the surface. Thus, in this study three different PAMAs, with increasingly surface mobility; poly (isobutyl methacrylate) (PIBMA), poly(butyl methacrylate) (PBMA), and poly(lauryl methacralate) (PLMA) along with pure titanium (Ti) substrates were implanted in the dorsum of Sprague-Dawley rats. Inflammatory cell recruitment, cell adhesion, and cytokine release were studied after 1, 3, and 28 days of implantation. Total number of inflammatory cells in the exudate was measured but no correlation between surface mobility and cell recruitment where found. However, the number of surface associated cells where significantly lower on the surfaces with high molecular mobility (PLMA and PBMA). The histological evaluation performed after 28 days revealed thicker fibrous capsule and a higher number of blood vessels on the low molecular mobility surface (PIBMA). After 28 days the cell activity was higher on the high molecular mobility surfaces (PLMA and PBMA) compared with PIBMA, based on the cytokine release. None of the surfaces induced any significant cell-death. On the basis of the results of this study we conclude that there is a significant difference in biological response to surfaces with different in molecular mobility. This might affect the wound healing process and the biocompatibility of biomaterials. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res, 2007 -------------------------------------------------------------------------------- Received: 13 March 2006; Revised: 15 December 2006; Accepted: 29 January 2007 Digital Object Identifier (DOI) 10.1002/jbm.a.31389 About DOI
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| 6. |
- Baghaei, Behnaz, et al.
(författare)
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Hemp/PLA Co-Wrapped Hybrid Yarns For Structured Thermoplastic Composites
- 2013
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Konferensbidrag (refereegranskat)abstract
- In recent years, natural fibre-reinforced polymer composites have been attracting attention from the viewpoint of reducing the impact on the natural environment. Currently, the use of thermoplastic resins in composites is clearly of higher potential than the use of thermoset. There are many thermoplastic polymers derived from renewable raw materials, which are also biodegradable. Polylactic acid (PLA) is one such candidate, and it shows rather good properties that are suitable for applications that do not require long-term durability or elevated mechanical performance at higher temperatures. In order to make their possible use in many technical applications more attractive, the mechanical properties of the PLA can be enhanced by using reinforcements. Hemp fibres can be considered to be a good choice for reinforcing polymer composites, due to their high stiffness, strength, and aspect ratio. Highly ordered textile reinforcements, such as interlaced woven fabrics and unidirectional fabrics made from natural-fibre yarns, perform considerably better than random non-woven mats in natural-fibre composites. At present, the commercially available plant-fibre yarns are not intended for structural composites, but for textiles, which have entirely different demands on the yarns. Thus, work is needed to tailor-make the best plant-fibre yarn for reinforcement of composites. This also includes investigation of the possibility of combining plant-fibre yarns with the matrix polymer in fibre form into one hybrid yarn (a composite preform), and how to do it (twisting or blending). It is well known that fibres provide the highest strength and stiffness when they are continuous and aligned in the direction of the applied load. Natural fibres are naturally discontinuous and conventional spun staple yarns tend to be highly twisted, which leads to fibre misalignment and poor resin wet-out. The structured natural-fibre composites reported so far are based on twisted yarns produced by long-established conventional spinning methods, mainly ring spinning. In this paper, we report our work on improving the orientation of hemp fibres in composites by using our recent development of co-wrapped yarn structures. This novel co-wrapped yarn consists of low twist and very fine hemp yarns next to PLA filaments in the core part, which are wrapped by PLA filaments. By varying the composition of hybrid yarn, it is possible to vary the hemp fibre content from 10 to 45 wt %. An exciting recent advancement has been a new family of aligned natural-fibre reinforcements, which has overcome these issues by using low twist yarns. We also report the influence of fibre content and wrap density (number of wraps per unit length) on the properties of composites. Before compression moulding, multilayer 0/90 bidirectional hybrid yarn prepregs were prepared by winding the hybrid yarn around a steel rectangular frame. We investigated the mechanical and thermo-mechanical properties of hemp-reinforced PLA composites. Compared to neat PLA, the tensile and flexural modulus and the strength of the PLA-hemp composites were significantly higher as a result of the increased fibre content. Impact strength of the composites decreased initially up to 10 wt % fibre loading, but even higher fibre loading caused an improvement in impact strength. From the DMTA results, it is evident that incorporation of the fibres gives a considerable increase in storage modulus and a decrease in tan δ values. These results show the reinforcing effect of hemp on PLA matrix. From the general trend in the results obtained, it can be affirmed that co-wrapped hybrid yarn with lower wrapping density leads to lower mechanical properties in the composite. The study performed with DSC revealed that the glass transition temperature and the crystalline melting point of PLA were not affected significantly after reinforcement with hemp. The crystallisation temperature of the hemp-reinforced PLA composites decreased compared to pure PLA, which indicates that the hemp fibres hinder the migration and diffusion of PLA molecular chains to the surface of the nucleus in the composites. No noteworthy differences in calorimetric data from DSC for composites were observed between the hybrid yarn preforms with different wrapping density. Future work will concentrate on efforts to evaluate the biodegradability of these developing and promising composites.
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| 7. |
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| 8. |
- Baghaei, Behnaz, et al.
(författare)
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Manufacture and characterisation of thermoplastic composites made from PLA/hemp co-wrapped hybrid yarn prepregs
- 2013
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Ingår i: Composites. Part A, Applied science and manufacturing. - : Elsevier Ltd. - 1359-835X .- 1878-5840. ; 50, s. 93-101
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Tidskriftsartikel (refereegranskat)abstract
- PLA/hemp co-wrapped hybrid yarns were produced by wrapping PLA filaments around a core composed of a 400 twists/m and 25 tex hemp yarn (Cannabis Sativa L) and 18 tex PLA filaments. The hemp content varied between 10 and 45 mass%, and the PLA wrapping density around the core was 150 and 250 turns/metre. Composites were fabricated by compression moulding of 0/90 bidirectional prepregs, and characterised regarding porosity, mechanical strength and thermal properties by dynamic mechanical thermal analysis (DMTA) and differential scanning calorimetry (DSC). Mechanical tests showed that the tensile and flexural strengths of the composites markedly increased with the fibre content, reaching 59.3 and 124.2 MPa when reinforced with 45 mass% fibre, which is approximately 2 and 3.3 times higher compared to neat PLA. Impact strength of the composites decreased initially up to 10 mass% fibre; while higher fibre loading (up to 45 mass%) caused an increase in impact strength up to 26.3 KJ/m2, an improvement of about 2 times higher compared to neat PLA. The composites made from the hybrid yarn with a wrapping density of 250 turns/metre showed improvements in mechanical properties, due to the lower porosity. The fractured surfaces were investigated by scanning electron microscopy to study the fibre/matrix interface.
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| 9. |
- Baghaei, Behnaz, et al.
(författare)
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Tailoring of the mechanical and thermal properties of hemp/PLA hybrid yarn composites
- 2013
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- In this study, we worked on improving the orientation of hemp fibres in composites by using our recent development of co-wrapped yarn structures. We investigated the influence of fibre content and wrap density on the properties of composites. Composites were fabricated by compression moulding of 0/90 bidirectional prepregs. Compared to neat PLA, the tensile and flexural modulus and the strength of the PLA-hemp composites were significantly higher as a result of the increased fibre content. Impact strength of the composites decreased initially up to 10 mass % fibre loading, but even higher fibre loading caused an improvement in impact strength. From the DMTA results, it was evident that incorporation of the fibres gives a considerable increase in storage modulus and a decrease in tan δ values. From the general trend in the results obtained, it can be affirmed that co-wrapped hybrid yarn with lower wrapping density leads to lower mechanical properties in the composite. The study performed with DSC revealed that the crystallisation temperature of the hemp-reinforced PLA composites decreased compared to pure PLA, which indicates that the hemp fibres hinder the migration and diffusion of PLA molecular chains to the surface of the nucleus in the composites.
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| 10. |
- Berglin, Lena
(författare)
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Biliary epithelial cells, the immune system and PSC pathogenesis
- 2015
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Primary sclerosing cholangitis (PSC) is a chronic, inflammatory liver disease that leads to destruction of the bile duct system. PSC is strongly associated with inflammatory bowel disease, and PSC patients have an increased risk of developing malignancies, especially cholangiocarcinoma (CCA). The pathogenesis of PSC is still insufficiently understood, although T cells have been suggested to play a major role. Little is known about the involvement of other immune cell populations. In addition to this, a better understanding is needed about the capacity of liver resident immune cells to prevent tumor development. In this thesis we have investigated cellular and humoral components of the immune system, in PSC and the PSC-associated malignancy CCA. In the first study, we examined the role of autoreactive antibodies in PSC patients. Flow cytometry was used to investigate the presence of IgA and IgG antibodies in PSC patient sera, and its reactivity against isolated human biliary epithelial cells. A majority of the patients had antibodies that bound to the cells, while only low levels could be detected in serum of healthy individuals. Moreover, IgA autoantibodies in PSC patients were associated with a reduced survival, and therefore their presence may be of importance in the pathogenesis of PSC. In the second and third study, immunohistochemistry and image analysis was used, to explore the cell compositions in PSC and CCA livers. Specific phenotypic patterns, associated with severity of disease, were revealed in PSC livers. T cells were enriched, mainly localizing to fibrotic fields, whereas MAIT cells were not equally increased. Furthermore, one group of PSC patients, characterized by a potential loss of smooth muscle cell function, was found to have increased numbers of T cells and a more extensive bile duct proliferation. The tumor microenvironment in CCA was characterized by a selective loss of Kupffer cells and MAIT cells, and contained high numbers of regulatory T cells. Moreover, the expression of IL-33 was significantly lower in tumors. This distinct intratumoral phenotype was unaffected by tumor location, tumor differentiation, or an underlying PSC. Altogether, our studies provide insights into the pathogenesis of PSC and CCA and opens up for further studies of disease mechanisms.
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