| 1. |
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| 2. |
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| 3. |
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| 4. |
- Bauer, Betty, et al.
(författare)
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Right temporal lobe activation when listening to emotionally significant music
- 2004
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Ingår i: Applied Neuropsychology. - : Informa UK Limited. - 0908-4282 .- 1532-4826. ; 11:3, s. 161-166
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Tidskriftsartikel (refereegranskat)abstract
- The cerebral activation when normal elderly participants (6 women, 6 men, M age = 70 years) listened to self-selected emotionally significant music was investigated. Musical memories and preferences were discussed in an interview, and a piece of music with great emotional significance to the participant was selected and later played during measurement of the regional cerebral blood flow (rCBF). Measurements were made during silence, individually selected emotional music, and standard neutral music. The right temporal lobe showed a significant (p < .01) increase in rCBF when the emotional music was compared to silence. A temporal lobe asymmetry (right > left) during emotional music was also significant (p < .01). A decrease in the left prefrontal areas reached significance (p < .05) when standard music was compared to silence. For the emotional music, the right prefrontal area showed a decrease (p < .05). Emotional music thus activates right temporal and deactivates prefrontal regions in the right hemisphere.
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| 5. |
- Bodin, Aase Katarina, 1977, et al.
(författare)
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CELL 11-Cells like cellulose scaffolds
- 2008
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Ingår i: Abstracts of Papers of the American Chemical Society. - 0065-7727. ; 235:APR 6
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)
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| 6. |
- Bodin, Aase Katarina, 1977, et al.
(författare)
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Influence of cultivation conditions on mechanical and morphological properties of bacterial cellulose tubes
- 2007
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Ingår i: Biotechnology and Bioengineering. - : Wiley. - 0006-3592 .- 1097-0290. ; 97:2, s. 425-434
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Tidskriftsartikel (refereegranskat)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. |
- Bodin, Aase Katarina, 1977, et al.
(författare)
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Modification of nanocellulose with a xyloglucan-RGD conjugate enhances adhesion and proliferation of endothelial cells: implications for tissue engineering.
- 2007
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Ingår i: Biomacromolecules. - : American Chemical Society (ACS). - 1526-4602 .- 1525-7797. ; 8:12, s. 3697-3704
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Tidskriftsartikel (refereegranskat)abstract
- This paper describes a novel method for introducing the RGD cell adhesion peptide to enhance cell adhesion onto bacterial cellulose (BC). BC and cotton linters as reference were modified with xyloglucan (XG) and xyloglugan bearing a GRGDS pentapeptide. The adsorptions followed Langmuir adsorption behavior, where both XGs probably decorate the cellulose surfaces as a monolayer. The adsorption maximum of the XGs reached around 180 mg/g on BC and only about three times as much on cotton linters. The adsorption was verified with colorimetric methods. The specific surface area of BC measured with XG and XG-GRGDS was about 200 m (2)/g and was almost three times less for cotton linters, 60 m (2)/g. The difference in the amounts of XGs adsorbed might be explained by the swollen network of bacterial cellulose and a more exposed and accessible bulk as compared to cotton linters. The nanocellulose material was modified homogeneously throughout the material, as seen by the z-scan in confocal microscopy. Moreover, the modification in the water phase, in comparison with organic solvents, was clearly advantageous for preserving the morphology, as observed with SEM. The modification slightly increased the wettability, which might explain the decrease in or undetectable adsorption of adhesive protein shown by QCM-D. Initial cell studies showed that adhesion of human endothelial cells is enhanced when the BC hydrogel is modified with XG-GRGDS. QCM-D studies further revealed that the cell enhancement is due to the presence of the RGD epitope on XG and not to a nonspecific adsorption of fibronectin from cell culture medium. Optimization and proliferation studies of human endothelial cells onto bacterial cellulose modified with XG-GRGDS are currently being carried out at the Vascular Engineering Center, Sahlgrenska University Hospital, Gothenburg.
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| 8. |
- Brorson, Håkan, et al.
(författare)
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Lymfsystemet och dess sjukdomar.
- 2005
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Ingår i: Kirurgi. - 9789144043555 ; 2nd ed, s. 469-488
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 9. |
- Brorson, Håkan, et al.
(författare)
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Lymfsystemet och dess sjukdomar
- 2001
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Ingår i: Kirurgi. - 9144016697 ; , s. 393-417
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 10. |
- Bäckdahl, Henrik, 1977, et al.
(författare)
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Engineering microporosity in bacterial cellulose scaffolds
- 2008
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Ingår i: Journal of tissue engineering and regenerative medicine. - : Hindawi Limited. - 1932-6254 .- 1932-7005. ; 2:6, s. 320-330
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Tidskriftsartikel (refereegranskat)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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| 11. |
- Bäckdahl, Henrik, 1977, et al.
(författare)
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Mechanical properties of bacterial cellulose and interactions with smooth muscle cells
- 2006
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Ingår i: Biomaterials. - : Elsevier BV. - 0142-9612 .- 1878-5905. ; 27:9, s. 2141-2149
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Tidskriftsartikel (refereegranskat)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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| 12. |
- Bäckdahl, Henrik, 1977, et al.
(författare)
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Observations on bacterial cellulose tube formation for application as vascular graft
- 2011
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Ingår i: Materials Science and Engineering C. - : Elsevier BV. - 0928-4931 .- 1873-0191. ; 31:1, s. 14-21
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Tidskriftsartikel (refereegranskat)abstract
- Nanocellulose (bacterial cellulose, BC), such as that produced by Acetobacter xylinum, has shown promising results as a replacement material for small diameter vascular grafts. The surface morphology of the lumen and mechanical properties of such tubes are crucial for their performance. The growth of a BC tube in a vertical fermentation bioreactor using silicone tubing for support and as an oxygen delivery membrane has not been studied in detail previously. Oxygen concentration and the number of bacteria added influence the production of the BC tubes. A dense and smooth luminal surface was formed after 4 days on a 3 mm silicone support. The bacteria were found to be in high concentration close to the silicon support and decreased in number further away. In the region with a high bacteria concentration, dense thin layers of BC were formed since the bacteria moved close together in this region. The presented observations were summarized in a theoretical model of BC tube growth.
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| 13. |
- Chuter, Timothy A M, et al.
(författare)
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A telescopic stent-graft for aortoiliac implantation
- 1997
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 13:1, s. 79-84
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To test a new delivery system for a telescopic stent-graft. MATERIALS: Variable overlap between the components of this stent-graft combination allows length adjustment. This device differs from other multi-component stent-grafts in that both components are contained within a single delivery system. METHODS: The stent-graft was implanted in the distal thoracic to suprarenal aorta of five pigs (35-50 kg), where the arterial diameter falls by almost 50%. The proximal and distal components of the stent-graft were targeted to bony landmarks in the vertebral column. RESULTS: Inspection of completion angiograms showed both proximal and distal stent-grafts to be within 1 mm of their target locations in all five experiments. Overall combined stent-graft length varied from 13.5 cm to 16.1 cm depending on the location of the bony landmark chosen as the distal target, and on the size of the pig. CONCLUSIONS: This system may be useful for the repair of abdominal aortic aneurysm whenever preoperative sizing is difficult due to aortic tortuosity, or precluded due to the urgency of the procedure.
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| 14. |
- Chuter, Timothy A M, et al.
(författare)
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Aneurysm pressure following endovascular exclusion
- 1997
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Ingår i: European Journal of Vascular and Endovascular Surgery. - 1532-2165. ; 13:1, s. 85-87
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: To assess the effect of stent-graft implantation on the pressure within an abdominal aortic aneurysm. METHODS: Aneurysm exclusion was performed using an aorto-uniiliac stent-graft in eight patients. Following stent-graft implantation, pressure measurements were performed through a catheter adjacent to the graft in the aneurysm. This "aneurysm pressure" was compared with radial arterial pressure. RESULTS: The pressure was lower in the aneurysm than in the radial artery, in all cases. Mean aneurysm pressure was 36.5/33.8 mmHg, while mean radial arterial pressure was 118.5/50.5 mmHg (p < 0.05, for both systolic and diastolic pressures). These findings corresponded with a reduction in the palpable abdominal pulse, and an absence of perigraft perfusion on follow-up computerised tomography. CONCLUSION: Stent-graft implantation produces a fall in the pressure within an abdominal aortic aneurysm.
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| 15. |
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| 16. |
- Delle, M., et al.
(författare)
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Preserved pelvic circulation after stent-graft treatment of complex aortoiliac artery aneurysms: a new approach
- 2005
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Ingår i: Journal of endovascular therapy. - 1526-6028. ; 12:2, s. 189-95
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: To describe an endovascular technique that allows stent-graft treatment of aortoiliac aneurysmal disease affecting both common iliac arteries (CIA), with maintenance of pelvic circulation on one side. TECHNIQUE: For patients with aortoiliac aneurysms, both common femoral arteries (CFA) were surgically exposed. One internal iliac artery (IIA) was initially embolized with coils. A bifurcated stent-graft main body was deployed with the proximal end just below the renal arteries. On the ipsilateral side, the stent-graft limb was extended 3 cm beyond the orifice of the embolized IIA into the external iliac artery (EIA) using stent-graft limb extenders. On the contralateral side, the stent-graft limb was deployed so that the distal end was 10 to 15 mm proximal to the patent IIA orifice. Via a left brachial artery access, the IIA was catheterized, and stent-grafts were deployed from the distal end of the contralateral AAA stent-graft limb into the IIA. A femorofemoral crossover graft provided circulation to the leg ipsilateral to the IIA stent-graft, and the EIA on the same side was ligated. The technique can also be modified to treat isolated bilateral CIA aneurysms. CONCLUSIONS: By extending the distal aspect of the stent-graft into an IIA, bilateral CIA aneurysms can be excluded while preserving pelvic circulation on one side.
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| 17. |
- Eriksson, Bengt I., 1946, et al.
(författare)
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Prevention of deep-vein thrombosis and pulmonary embolism after total hip replacement. Comparison of low-molecular-weight heparin and unfractionated heparin.
- 1991
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Ingår i: The Journal of bone and joint surgery. American volume. - 0021-9355. ; 73:4, s. 484-93
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Tidskriftsartikel (refereegranskat)abstract
- In a prospective, randomized, double-blind study, the efficacy and safety of a low-molecular-weight heparin were compared with those of unfractionated sodium heparin (standard heparin) in 136 patients who had elective total hip replacement. The patients received subcutaneous injection of either 5000 international units of low-molecular-weight heparin once daily or 5000 international units of standard heparin three times a day. Treatment with low-molecular-weight heparin began twelve hours before the operation, and treatment with standard heparin began two hours preoperatively; both regimens were continued for ten days. Twelve days postoperatively, bilateral ascending phlebography was performed in 122 patients, sixty-three in the treatment group that received low-molecular-weight heparin and fifty-nine in the treatment group that received standard heparin. Pulmonary scintigraphy was performed in 127 patients. Deep-vein thrombosis was diagnosed in forty-four patients: nineteen (30 per cent) of the sixty-three who received low-molecular-weight heparin and twenty-five (42 per cent) of the fifty-nine who received standard heparin. All but four patients, two from each treatment group, were asymptomatic. The difference in the total rate of thrombosis in the two groups was not significant (p = 0.189). However, thrombosis occurred in the thigh in only six (10 per cent) of the patients who received low-molecular-weight heparin but in eighteen (31 per cent) of those who received standard heparin, a significant difference (p = 0.011). Pulmonary embolism was detected in twenty-seven patients: eight (12.3 per cent) of those who received low-molecular-weight heparin and nineteen (30.6 per cent) of those who received standard heparin. Only three patients had clinical signs of embolism. Pulmonary embolism was significantly more frequent in the group that received standard heparin (p = 0.016). Total loss of blood and the total amount of blood that was transfused were significantly reduced in the patients who received low-molecular-weight heparin compared with those who received standard heparin. Prophylaxis was not discontinued because of hemorrhage in any patient. The efficacy of low-molecular-weight heparin was superior to that of standard heparin in the prevention of femoral thrombosis and pulmonary embolism, although the over-all incidence of deep-vein thrombosis was not statistically different.(ABSTRACT TRUNCATED AT 400 WORDS)
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| 18. |
- Esguerra, Maricris, 1981, et al.
(författare)
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Intravital fluorescent microscopic evaluation of bacterial cellulose as scaffold for vascular grafts.
- 2010
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Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 93:1, s. 140-9
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Tidskriftsartikel (refereegranskat)abstract
- Although commonly used synthetic vascular grafts perform satisfactorily in large caliber blood vessels, they are prone to thrombosis in small diameter vessels. Therefore, small vessels might benefit from tissue engineered vascular grafts. This study evaluated bacterial cellulose (BC) as a potential biomaterial for biosynthetic blood vessels. We implanted the dorsal skinfold chambers in three groups of Syrian golden hamsters with BC (experimental group), polyglycolic acid, or expanded polytetrafluorethylene (control groups). Following implantation, we used intravital fluorescence microscopy, histology, and immunohistochemistry to analyze the biocompatibility, neovascularization, and incorporation of each material over a time period of 2 weeks. Biocompatibility was good in all groups, as indicated by the absence of leukocyte activation upon implantation. All groups displayed angiogenic response in the host tissue, but that response was highest in the polyglycolic acid group. Histology revealed vascularized granulation tissue surrounding all three biomaterials, with many proliferating cells and a lack of apoptotic cell death 2 weeks after implantation. In conclusion, BC offers good biocompatibility and material incorporation compared with commonly used materials in vascular surgery. Thus, BC represents a promising new biomaterial for tissue engineering of vascular grafts.
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| 19. |
- Fink, Helen, 1978, et al.
(författare)
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An in vitro study of blood compatibility of vascular grafts made of bacterial cellulose in comparison with conventionally-used graft materials
- 2011
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Ingår i: Journal of Biomedical Materials Research - Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 97A:1, s. 52-58
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Tidskriftsartikel (refereegranskat)abstract
- In this study we analyzed the blood compatibility of bacterial cellulose (BC) as a new biosynthetic material for use as a vascular graft. As reference materials we used expanded polytetrafluoroethylene (ePTFE) and poly(ethylene terephthalate) (PET) vascular grafts. These materials are in clinical use today. Tubes with inner diameters of both 4 (not PET) and 6 mm were tested. Heparin-coated PVC tubes (hepPVC) were used as a negative control. Platelet consumption and thrombin-antithrombin complex (TAT) were used as parameters of coagulation and for complement activation, sC3a and sC5b-9 were used. The investigated parameters were measured after 1-h exposure to freshly drawn human blood supplemented with a low dose of heparin in a Chandler loop system. The results showed that BC exhibits no significant difference in platelet consumption, as compared with PET 16 mm), ePTFE and hepPVC. The PET material consumed more platelets than any of the other materials. The TAT generation for 4 mm tubes was not significantly different between BC and the other materials. For 6 mm tubes, however, differences were observed between hepPVC and PET (p < 0.0001); BC and hepPVC (p = 0.0016); ePTFE and PET (p < 0.0001); BC and ePTFE (p = 0.0029); BC and PET (p = 0.0141). Surprisingly, considering the low platelet consumption, the complement activation parameters (sC3a and sC5b-9) were much higher for BC, as compared with the other materials for both 4 and 6 mm tubes.
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| 20. |
- Fink, Helen, 1978, et al.
(författare)
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Bacterial cellulose modified with xyloglucan bearing the adhesion peptide RGD promotes endothelial cell adhesion and metabolism--a promising modification for vascular grafts.
- 2011
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Ingår i: Journal of tissue engineering and regenerative medicine. - : Hindawi Limited. - 1932-7005 .- 1932-6254. ; 5:6, s. 454-63
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Tidskriftsartikel (refereegranskat)abstract
- Today, biomaterials such as polytetrafluorethylene (ePTFE) are used clinically as prosthetic grafts for vascular surgery of large vessels (>5 mm). In small diameter vessels, however, their performance is poor due to early thrombosis. Bacterial-derived cellulose (BC) is a new promising material as a replacement for blood vessels. This material is highly biocompatible in vivo but shows poor cell adhesion. In the native blood vessel, the endothelium creates a smooth non-thrombogenic surface. In order to sustain cell adhesion, BC has to be modified. With a novel xyloglucan (XG) glycoconjugate method, it is possible to introduce the cell adhesion peptide RGD (Arg-Gly-Asp) onto bacterial cellulose. The advantage of the XG-technique is that it is an easy one-step procedure carried out in water and it does not weaken or alter the fiber structure of the hydrogel. In this study, BC was modified with XG and XGRGD to asses primary human vascular endothelial cell adhesion, proliferation, and metabolism as compared with unmodified BC. This XG-RGD-modification significantly increased cell adhesion and the metabolism of seeded primary endothelial cells as compared with unmodified BC whereas the proliferation rate was affected only to some extent. The introduction of an RGD-peptide to the BC surface further resulted in enhanced cell spreading with more pronounced stress fiber formation and mature phenotype. This makes BC together with the XG-method a promising material for synthetic grafts in vascular surgery and cardiovascular research.
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| 21. |
- Fink, Helen, 1978, et al.
(författare)
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Real-time measurements of coagulation on bacterial cellulose and conventional vascular graft materials.
- 2010
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Ingår i: Acta biomaterialia. - : Elsevier BV. - 1878-7568 .- 1742-7061. ; 6:3, s. 1125-30
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Tidskriftsartikel (refereegranskat)abstract
- The search for a functional, small diameter (<5mm) vascular graft has been ongoing for over 30 years, but yet there is no consistently reliable synthetic graft. The primary mechanisms of graft failure are intimal hyperplasia, poor blood flow and surface thrombogenicity. Bacterial cellulose (BC) became therefore a proposed new biosynthetic vascular graft material. Since conventional methods are not suited for coagulation measurements on BC, we have adapted the automated calibrated thrombin generation method for measurements of biomaterial-induced coagulation of BC as compared with clinically used graft materials i.e., expanded poly(tetrafluoroethylene) (ePTFE) and poly(ethyleneterephtalat) (PET). We have also visualized the coagulation propagation at the material surfaces. Thrombin generation experiments revealed dramatic differences between the materials tested. Both ePTFE and BC were found to generate longer lag times and ttpeak values than PET. Most importantly, BC was found to generate the lowest "peak", indicating a slower coagulation process at the surface. These results are also supported by the measurements of factor XIIa generation and analysis of surface coagulation times, which were detected in the following increasing order (mean + or - SD): PET (27 + or - 8 min)
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| 22. |
- Fogelstrand, Per, 1971, et al.
(författare)
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External collar inhibits balloon-induced intimal hyperplasia in rabbits.
- 2002
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Ingår i: Journal of vascular research. - 1018-1172. ; 39:4, s. 361-7
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Tidskriftsartikel (refereegranskat)abstract
- Intimal hyperplasia is a common complication following vascular interventions. To understand the underlying pathophysiology, the focus has mainly been on the intima and media. The adventitia has been less investigated, although adventitial hyperplasia is seen together with intimal hyperplasia. If the adventitial response is an important part of the process, the adventitia might be a target to inhibit intimal hyperplasia. In the present study we investigated whether an external collar attenuating the adventitial thickness could inhibit a balloon-induced intimal hyperplasia. The common carotid artery was injured in rabbits (n = 6) with a 3-french balloon catheter. The mid portion of the injured artery was encircled with a silicone collar (diameter = 2.0 mm). After 14 days the balloon-induced neointima was reduced by 54 +/- 6.3% underneath the collar. The adventitial and medial thickenings were also attenuated (36 +/- 8.7 and 44 +/- 4.3%, respectively). This study demonstrates that intimal hyperplasia following balloon injury can be inhibited with an external collar. This supports the idea of the adventitia as a potential target to inhibit intimal hyperplasia.
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| 23. |
- Helenius, Gisela, 1973, et al.
(författare)
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Effect of shear stress on the expression of coagulation and fibrinolytic factors in both smooth muscle and endothelial cells in a co-culture model.
- 2008
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Ingår i: European surgical research. Europ?ische chirurgische Forschung. Recherches chirurgicales europ?ennes. - : S. Karger AG. - 1421-9921 .- 0014-312X. ; 40:4, s. 325-32
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Tidskriftsartikel (refereegranskat)abstract
- Blood vessels are subjected to forces due to the flow. Endothelial cells (EC) are recipients, cross-talk with smooth muscle cells (SMC), and regulate physiology. It was hypothesized that both EC and SMC respond to shear stress, which alters the expression of factors in coagulation and fibrinolysis. METHODS: A co-culture of human saphenous vein EC (HSVEC) and human saphenous vein SMC (HSVSMC) was exposed to shear, following which the cells were separated. Gene expression of tissue factor, thrombomodulin (TM), plasminogen activator inhibitor-1 (PAI-1), tissue plasminogen activator (tPA) and urokinase plasminogen activator (uPA) were analyzed with real-time RT-PCR. Protein expression was studied with ELISA. In HSVEC, the expression of PAI-1 (x2.1), tPA (x1.8), uPA (x1.6), tissue factor (x2.5) and TM (x1.9) was upregulated after 4 h of shear compared to controls. After 24 h of shear, expression was still upregulated in tPA (x2.3) and TM (x1.6). In HSVSMC, change in expression of PAI-1 (x2.1) was present after 4 h and in uPA (x2.1), and TM (x0.4) after 24 h. Both HSVEC and HSVSMC responded to shear, which led to altered expression of coagulation and fibrinolytic factors. This indicates that SMC, and interactions between EC and SMC, are more important in the regulation of vascular wall hemostasis than earlier studies have reported.
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| 24. |
- Helenius, Gisela, 1973, et al.
(författare)
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Expression of fibrinolytic and coagulation factors in cocultured human endothelial and smooth muscle cells
- 2004
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Ingår i: Tissue engineering. - 1076-3279. ; 10:3-4, s. 353-60
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Tidskriftsartikel (refereegranskat)abstract
- Interactions between endothelial cells and smooth muscle cells are interesting from a tissue-engineering point of view. We have developed a coculture system that allows direct contact between these two cell types. The fibrinolytic factors PAI-1, tPA, and uPA and the coagulation factor TF, were studied at the gene level by RT-PCR and at the protein level by ELISA. Significant changes of all studied factors were seen at the gene level in cocultured endothelial cells. tPA and TF were upregulated 4- and 7-fold, respectively, and PAI-1 and uPA were downregulated 4- and 1.5-fold, respectively, compared with single-cultured controls. In cocultured smooth muscle cells alterations of PAI-1 and TF were significant, with a 1.5-fold upregulation of PAI-1 and a 2.5-fold downregulation of TF. Results at the protein level mirrored the gene expression results. These findings indicate that cocultured endothelial cells are rendered both hypercoagulative and hyperfibrinolytic.
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| 25. |
- Helenius, Gisela, 1973, et al.
(författare)
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In vivo biocompatibility of bacterial cellulose
- 2006
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Ingår i: Journal of biomedical materials research. - : Wiley. - 1549-3296 .- 1552-4965. ; 76:2, s. 431-8
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Tidskriftsartikel (refereegranskat)abstract
- The biocompatibility of a scaffold for tissue engineered constructs is essential for the outcome. Bacterial cellulose (BC) consists of completely pure cellulose nanofibrils synthesized by Acetobacter xylinum. BC has high mechanical strength and can be shaped into three-dimensional structures. Cellulose-based materials induce negligible foreign body and inflammatory responses and are considered as biocompatible. The in vivo biocompatibility of BC has never been evaluated systematically. Thus, in the development of tissue engineered constructs with a BC scaffold, it is necessary to evaluate the in vivo biocompatibility. BC was implanted subcutaneously in rats for 1, 4, and 12 weeks. The implants were evaluated in aspects of chronic inflammation, foreign body responses, cell ingrowth, and angiogenesis, using histology, immunohistochemistry, and electron microscopy. There were no macroscopic signs of inflammation around the implants. There were no microscopic signs of inflammation either (i.e., a high number of small cells around the implants or the blood vessels). No fibrotic capsule or giant cells were present. Fibroblasts infiltrated BC, which was well integrated into the host tissue, and did not elicit any chronic inflammatory reactions. The biocompatibility of BC is good and the material has potential to be used as a scaffold in tissue engineering.
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