| 1. |
- Andersson, Jessica, et al.
(author)
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Behavior of human chondrocytes in engineered porous bacterial cellulose scaffolds
- 2010
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In: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 94A:4, s. 1124-1132
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Journal article (peer-reviewed)abstract
- Regeneration of articular cartilage damage is an area of great interest due to the limited ability of cartilage to self-repair. The latest cartilage repair strategies are dependent on access to biomaterials to which chondrocytes can attach and in which they can migrate and proliferate, producing their own extracellular matrix. In the present study, engineered porous bacterial cellulose (BC) scaffolds were prepared by fermentation of Acetobacter xylinum (A. xylinum) in the presence of slightly fused wax particles with a diameter of 150-300 mu m, which were then removed by extrusion. This porous material was evaluated as a scaffold for cartilage regeneration. Articular chondrocytes from young adult patients as well as neonatal articular chondrocytes were seeded with various seeding techniques onto the porous BC scaffolds. Scanning electron microscopy (SEM) analysis and confocal microscopy analysis showed that cells entered the pores of the scaffolds and that they increasingly filled out the pores over time. Furthermore, DNA analysis implied that the chondrocytes proliferated within the porous BC. Alcian blue van Gieson staining revealed glycosaminoglycan (GAG) production by chondrocytes in areas where cells were clustered together. With some further development, this novel biomaterial can be a suitable candidate for cartilage regeneration applications.
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| 2. |
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| 3. |
- Aspegren, Anders, et al.
(author)
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Storbritanniens satsning på tidig detektion av cancer med hjälp av flytande biopsier – beskrivning och analys
- 2023
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Reports (other academic/artistic)abstract
- Det pågår omfattande studier, framför allt i USA och Storbritannien, som undersöker möjligheterna att införa screening med hjälp av blodprover för tidig upptäckt av ett flertal cancerformer, så kallade MCED (Mulitple Cancer Early Detection). Ännu har inget faktiskt screeningsprogram med MCED-screening initierats i världen. I Sverige ställs idag höga krav på evidens från studier för att ett screeningprogram ska kunna införas. Det pågår studier som adresserar frågan om screening, men än så länge saknas mycket information. Med utgångspunkt i denna rapport kan därför inte en initiering av MCEDscreening i Sverige rekommenderas i dagsläget. För att vara i framkant bör Sverige dock följa området nogsamt. Grail är ett väletablerat företag som i augusti 2021 blev uppköpt av Illumina, ett företag som 2020 rapporterade en vinst på 2,34 miljarder USD. Företaget har stora ambitioner för framtida screeningprogram och kan bedömas ha de resurser som krävs att genomföra essentiella studier. De har säkrade medel och genomför projekt för att utveckla sin produkt för att fungera i en screeningsituation. Storbritanniens stora pågående studie ”NHS-Galleri Clinical Trial” beräknas publicera nya resultat under 2023. Om denna studie faller ut väl planeras en utvidgning av studien som ska omfatta en miljon personer. Denna större studie beräknas kunna avslutas 2030. Data att följa i nämnda ovanstående studie är bland annat: - Hur stor population ännu icke diagnostiserade utgör, i empiriska siffror - Utvecklingen av testmetoden gällande sensibilitet och sensitivitet - Patientnyttan, t.ex. ökar överlevnaden mot dagens siffror - Risken för överdiagnostik - Kostnader och logistik som kommer belasta sjukvården En problematik med MCED-screening är att testernas specificitet och sensitivitet behöver vara tillräckligt tillförlitliga för att det inte skall belasta snarare hjälpa samhället. Det är osannolikt att dessa värden kommer att vara 100-procentiga, men hur bra dessa värden bör vara innan man inför en screening är öppet för diskussion, däri ligger problematiken. I rapporten förklaras dessa begrepp i mer detalj. Det bör nämnas att Grail redan har kunnat presentera en ökad prestanda utifrån preliminära resultat ifrån pågående studier som presenterats i en så kallad sub-studie, där sensitivitet, sensibilitet och ”Tissue of Origin” (TOO) har förbättrats ytterligare gällande tolv olika cancerformer. Beräkningar i vår rapport har nyttjat dessa värden för att söka ge en bild över vad som kan förväntas vid ett införande av en Grail-MCED-screening i Sverige. För de tolv cancerformerna kan beräkningarna sammanfattas enligt; - Under förutsättning att det finns adekvat behandling att erbjuda vid tidigare diagnostik, kommer det ske en markant förskjutning av i vilket stadie som diagnostiserade individer detekteras och förhoppningsvis behandlas. Idag behandlas cirka 40 -45% av de cancerdiagnostiserade i stadie III/IV, att jämföras mot de beräknade 6% vid införande av årlig screening. - Ökningen av antalet individer som skulle överleva sin cancer uppskattas till mellan 3 - 5 000 individer, utöver de cirka 9 000 som överlever med hjälp av dagens diagnostik/behandling. - 25 – 35% kostnadsreducering både vad gäller direkta kostnader och samhällskostnader, extrapolerat från IHE rapport (1). Vi har dock inte tagit hänsyn till de kostnadsökningar ett införande av en MCED-screening skulle innebära. Det reella värdet av rapportens beräkningar bör vägas mot de empiriska data som kommer produceras av NHS studie av Grails metod. Starka avvikelser (”positiva/negativa”) från empiriska data kan då ligga till grund för om och i så fall hur pass snabbt man vill driva införande av MCED screening i Sverige. Rapportens sammantagna bedömning är att de av Socialstyrelsen uppsatta kriterier för införande av en screening, inte är uppfyllda i dagsläget. Men vi har även försökt visualisera vad som skulle komma att ske med dagens diagnostiserade cancerpatientgrupper om en MCED-screening införs i ålderspopulationen 40 – 80 år (96% av dagens diagnostiserade), på de tolv cancerformer som metoden visar bäst sensibilitet/sensitivitet mot. Dessa tolv cancerformer utgör 36% av dagens diagnostiserade patienter. Trots att ett införande av screening inte är att rekommendera i dagsläget, finns det alternativ att ta ställning till; - Endast avvakta utredningarna i Storbritannien (till 2023, eller till 2030). - Avvakta utredningarna men initiera samtal med beslutsfattare som styr över de ekonomiska medel som kan bistå med satsningar på större Grailtester i Sverige - Avvakta utredningarna, men initiera samtal med både NHS och Grail i syfte att behålla momentum i detta första initiativ till utredning. Författarnas uppfattning är att Grails teknik är signifikant och kommer med stor sannolikhet bedömas som tillämpbar för MCED-screening i framtiden.
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| 4. |
- Bodin, A, et al.
(author)
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Bacterial Cellulose as Biomaterial
- 2011
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In: Comprehensive Biomaterials. - : Elsevier. - 9780080552941 ; , s. 405-410
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Book chapter (peer-reviewed)
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| 5. |
- Bodin, Aase Katarina, 1977, et al.
(author)
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CELL 11-Cells like cellulose scaffolds
- 2008
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In: Abstracts of Papers of the American Chemical Society. - 0065-7727. ; 235:APR 6
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Conference paper (other academic/artistic)
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| 6. |
- Bodin, Aase Katarina, 1977, et al.
(author)
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Influence of cultivation conditions on mechanical and morphological properties of bacterial cellulose tubes
- 2007
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In: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 97:2, s. 425-434
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Journal article (peer-reviewed)abstract
- Bacterial cellulose (BC) was deposited in tubular form by fermenting Acetobacter xylinum on top of silicone tubes as an oxygenated support and by blowing different concns. of oxygen, i.e., 21% (air), 35%, 50%, and 100%. Mech. properties such as burst pressure and tensile properties were evaluated for all tubes. The burst pressure of the tubes increased with an increase in oxygen ratio and reached a top value of 880 mmHg at 100% oxygen. The Young's modulus was approx. 5 MPa for all tubes, irresp. of the oxygen ratio. The elongation to break decreased from 30% to 10-20% when the oxygen ratio was increased. The morphol. of the tubes was characterized by SEM (SEM). All tubes had an even inner side and a more porous outer side. The cross section indicated that the tubes are composed of layers and that the amt. of layers and the yield of cellulose increased with an increase in oxygen ratio. We propose that an internal vessel wall with high d. is required for the tube to sustain a certain pressure. An increase in wall thickness by an increase in oxygen ratio might explain the increasing burst pressure with increasing oxygen ratio. The fermn. method used renders it possible to produce branched tubes, tubes with unlimited length and inner diams. Endothelial cells (ECs) were grown onto the lumen of the tubes. The cells formed a confluent layer after 7 days. The tubes potential as a vascular graft is currently under investigation in a large animal model at the Center of Vascular Engineering, Sahlgrenska University Hospital, Gothenburg.
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| 7. |
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| 8. |
- Bäckdahl, Henrik, 1977, et al.
(author)
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Engineering microporosity in bacterial cellulose scaffolds
- 2008
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In: Journal of tissue engineering and regenerative medicine. - : Hindawi Limited. - 1932-6254 .- 1932-7005. ; 2:6, s. 320-330
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Journal article (peer-reviewed)abstract
- The scaffold is an essential component in tissue engineering. A novel method to prepare threedimensional (3D) nanofibril network scaffolds with controlled microporosity has been developed. By placing paraffin wax and starch particles of various sizes in a growing culture of Acetobacter xylinum, bacterial cellulose scaffolds of different morphologies and interconnectivity were prepared. Paraffin particles were incorporated throughout the scaffold, while starch particles were found only in the outermost area of the resulting scaffold. The porogens were successfully removed after culture with bacteria and no residues were detected with electron spectroscopy for chemical analysis (ESCA) or Fourier transform infra-red spectroscopy (FT-IR). Resulting scaffolds were seeded with smooth muscle cells (SMCs) and investigated using histology and organ bath techniques. SMC were selected as the cell type since the main purpose of the resulting scaffolds is for tissue engineered blood vessels. SMCs attached to and proliferated on and partly into the scaffolds. Copyright © 2008 John Wiley & Sons, Ltd.
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| 9. |
- Bäckdahl, Henrik, 1977
(author)
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Engineering the shape of bacterial cellulose and its use as blood vessel replacement
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Tissue loss and organ failure are major health problems that impose great costs on society. Cardiovascular diseases are responsible for 36% of mortalities and the disease burden among adults over the age of 60. The single largest cardiovascular disease is atherosclerosis in the coronary artery. Methods of treatment depend upon its severity and include drug therapy, coronary artery angioplasty and coronary bypass grafting.Approximately every tenth patient unfortunately lacks native replacement vessels. Synthetic grafts based on polyester or expanded polytetrafluoroethylene work satisfactorily at diameters larger than 6mm, but they become occluded as a result ofthrombosis when smaller diameters are used. Despite enormous efforts, scientists have yet not found a suitable solution. Tissue engineered blood vessels (TEBV) represent anattractive approach for overcoming reconstructive problems associated with vascular diseases by providing small calibre vascular grafts. The aim of this study was to evaluate anovel biosynthetic biomaterial, bacterial cellulose (BC), as a potential graft and as a scaffold for TEBV.Biopolymers are a family of materials that we think can be used to mimick structures in the human body. BC is a biopolymer excreted by Acetobacter Xylinum into anetwork of nanofibrils. We found that the dimensions and morphology of cellulose nanofibrils were similar to those of collagen. By creating an interface between air andculture medium in different shapes, we were able to alter the shape of the resulting biomaterial. We found that the mechanical properties of bacterial cellulose are far moresimilar to those of collagen in a blood vessel than are the properties of synthetic materials such as expanded polytetrafluorethylene. BC tubes, both straight and branched, were successfully developed.Cell cultures on the material showed that human smooth muscle cells could adhere to and proliferate on as well as migrate into the material while endothelial cells could forma confluent layer on the luminal side of the BC tubes. An in vivo evaluation of biocompatibility showed that bacterial cellulose is very well integrated into the host tissueand does not elicit any chronic inflammatory reactions. The biocompatibility of BC must be considered good, and the material therefore has the potential to be used as a scaffold for tissue engineered products.A toolbox was developed that allowed us to tailor the porosity and interconnectivity of the nanofibril network. The shape of the pores could also be altered. With such atoolbox, a scaffold of any shape on the nano scale can be constructed out of fibrils. This work contributes to the knowledge of relationships between the BC structure, its material properties and tissue interaction. Further in vivo evaluation is needed to determine the scaffolds’ and grafts’ biocompatibility. The future cell studies will show potential of microporous BC as a scaffold for TEBV but also other tissues and organ. It is our hope that this will result at a later stage in a product that can help the many patients in need. The development of functioning small diameter blood vessel substitute is awaited with keeninterest by all patients with severe cardiovascular diseases.
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| 10. |
- Bäckdahl, Henrik, 1977, et al.
(author)
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Mechanical properties of bacterial cellulose and interactions with smooth muscle cells
- 2006
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In: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 27:9, s. 2141-2149
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Journal article (peer-reviewed)abstract
- Tissue engineered blood vessels (TEBV) represent an attractive approach for overcoming reconstructive problems associated with vascular diseases by providing small calibre vascular grafts. The aim of this study has been to evaluate a novel biomaterial, bacterial cellulose (BC), as a potential scaffold for TEBV. The morphology of the BC pellicle grown in static culture was investigated with SEM. Mechanical properties of BC were measured in Krebs solution and compared with the properties of porcine carotid arteries and ePTFE grafts. Attachment, proliferation and ingrowth of human smooth muscle cells (SMC) on the BC were analysed in vitro. The BC pellicle had an asymmetric structure composed of a fine network of nanofibrils similar to a collagen network. The shape of the stress-strain response of BC is reminiscent of the stress-strain response of the carotid artery, most probably due to the similarity in architecture of the nanofibrill networks. SMC adhered to and proliferated on the BC pellicle; an ingrowth of up to 40 microm was seen after 2 weeks of culture. BC exhibit attractive properties for use in future TEBV.
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