| 1. |
- Eriksson, Mathilda, et al.
(författare)
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Utilization of a right-handed coiled-coil protein from archaebacterium Staphylothermus marinus as a carrier for cisplatin
- 2009
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Ingår i: Anticancer Research. - 0250-7005 .- 1791-7530. ; 29:1, s. 11-18
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: The nano-sized right-handed coiled-coil (RHCC) protein, originating from the archaebacterium Staphylothermus marinus, is stable at high salt concentrations, high temperatures, high pressures and extremes of pH. Its crystal structure reveals four hydrophobic cavities which can incorporate heavy metals. Nano-sized compounds have been used to carry cytotoxic drugs to tumours, avoiding delivery to healthy tissue, in part due to enhanced permeability in tumour blood vessels (enhanced permeability and retention effect). MATERIALS AND METHODS: The ability of RHCC to carry the platinum-containing chemotherapeutic drug cisplatin to cells, while retaining the cytotoxic potential was tested both in vitro and in vivo. RESULTS: RHCC was able to bind and enter cells in vitro and was not severely toxic or immunogenic in mice. Moreover, RHCC incorporated cisplatin, without inhibiting the cytotoxic potential of the drug against tumour cell lines in vitro or in vivo. CONCLUSION: RHCC can be used as a carrier of cisplatin without abrogating the effect of the drug.
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| 2. |
- Platou Vikinge, Trine, 1966-
(författare)
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Surface Plasmon Resonance for the Detection of Coagulation and Protein Interactions
- 1999
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Medical improvements rely on methodological inventions and developments and on the steadily increasing knowledge of human physiology. This thesis presents methodological developments enabling the study of body fluid interactions with a material surface under more realistic and physiologically relevant conditions than previously possible.By use of the surface plasmon resonance (SPR) technique biological interactions on a sensor surface can be detected in real time as changes in refractive index. We studied biological interactions in blood-derived fluids, and experienced the difficulties related to refractive index changes from irrelevant components of the analyte interacting with the ligand on the sensor surface. However, with the use of avian antibodies, interacting minimally with the human complement system, instead of murine ones for analyte capture this problem was averted, and the human serum concentration of the C3 protein could be reproducibly determined.A novel use of the SPR based technique for the detection of clotting time was developed. The placement of whole blood or blood plasma samples on an SPR sensor surface gave sigmoid response signals. Curve fit analysis followed by feature extraction revealed that the SPR signal was sensitive to concentrations of coagulation activator and inhibitor in the sample. The structures left on the sensor surfaces after completed clotting (followed by a rinse and dry procedure) were imaged via atomic force microscopy (AFM). The AFM images revealed mesh-works of fibres with size distributions reflecting the concentration of coagulation activator in the sample. This supports the interpretation of the SPR signal as being due to the fibrin polymerisation process of the coagulation system.The detection of clotting with SPR was compared to the clinically used nephelometric technique. Statistical analysis indicated that the two methods are equally reliable, and the differences in observed clotting times could be ascribed to the difference in temperature at which the instruments were operated. Whereas nephelometric clotting detection requires plasma preparation, the SPR technique can be used also for the measurement of whole blood clotting.The comparison of clotting time as measured with SPR and with a quartz crystal microbalance device with energy dissipation detection (QCM-D) revealed that the former gives shorter clotting times at high concentrations of activator. This is because SPR does not require the biological material to be coupled to the surface to be detected, whereas QCM does. Without addition of coagulation activator to the sample the clotting process seemed to be surface initiated as the two methods gave literally the same clotting times. The energy dissipation detected by the QCM-D yielded interesting information on the viscoelastic properties of the clots, that could be related to the rigidity and viscosity of the samples.Finally, G-protein-coupled receptors were investigated, being of prime importance in the understanding of a number of presently used medical drugs, but also relevant in the understanding of platelet function and their role in the coagulation cascade. A surface specifically binding the G-protein, and not its α or βγ subunits, was constructed by immobilisation of a synthetic peptide derived from a G-protein-coupled receptor (α2A-adrenoceptor) to the SPR sensor surface. The G-protein capturing efficiency was shown to depend on the orientation and extension of the peptide on the surface, and the method is a promising tool in the study of specificity and efficiency of drugs targeted at G-proteins.
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| 3. |
- Vikinge, Trine P., et al.
(författare)
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Blood plasma coagulation studied by surface plasmon resonance
- 1999
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Ingår i: BIOMEDICAL SENSORS, FIBERS, AND OPTICAL DELIVERY SYSTEMS, PROCEEDINGS. - : SPIE - International Society for Optical Engineering. ; , s. 107-114
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Konferensbidrag (refereegranskat)abstract
- A surface plasmon resonance (SPR) apparatus was used to investigate blood plasma coagulation in real-time as a function of thromboplastin and heparin concentrations. The physical reason for the SPR signal observed is discussed and 3 different models are proposed. The response curves were analyzed by multivariable curve fitting followed by feature extraction. Interesting parameters of the sigmoid curves were lag time, slope and maximum response. When thromboplastin concentrations were increased, the lag-time decreased and the slope of the curve increased. A prolonged clotting time was mostly followed by increased maximum response, with exception for samples with no or very little thromboplastin added. High heparin concentrations changed the clotting kinetics, as seen from the lag-time vs. slope relation. Atomic force microscopy (AFM) pictures of sensor surfaces dried after completed clotting, revealed differences in fibrin network structures as a function of thromboplastin concentration, and fiber thickness increased with lower thromboplastin concentration. The results correlate well with present common methods.
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| 4. |
- Vikinge, Trine P., et al.
(författare)
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Blood plasma coagulation studied by surface plasmon resonance
- 2000
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Ingår i: Journal of Biomedical Optics. - : SPIE-Intl Soc Optical Eng. - 1083-3668 .- 1560-2281. ; 5:1, s. 51-55
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Tidskriftsartikel (refereegranskat)abstract
- A surface plasmon resonance (SPR) apparatus was used to investigate blood plasma coagulation in real time as a function of thromboplastin and heparin concentrations. The response curves were analyzed by curve fitting to a sigmoid curve equation, followed by extraction of the time constant. Clotting activation by thromboplastin resulted in increased time constant, as compared to spontaneously clotted plasma, in a dose dependent way. Addition of heparin to the thromboplastin-activated plasma counteracted this effect. Atomic force microscopy (AFM) pictures of sensor surfaces dried after completed clotting, revealed differences in fibrin network structures as a function of thromboplastin concentration, and the fiber thickness increased with decreased thromboplastin concentration. The physical reason for the SPR signal observed is ambiguous and is therefore discussed. However, the results summarized in the plots and the fibrin network properties observed by AFM correlate well with present common methods used to analyze blood coagulation.
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| 5. |
- Vikinge, Trine P., et al.
(författare)
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Comparison of surface plasmon resonance and quartz crystal microbalance in the study of whole blood and plasma coagulation
- 2000
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Ingår i: Biosensors & bioelectronics. - 0956-5663 .- 1873-4235. ; 15:11-12, s. 605-613
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Tidskriftsartikel (refereegranskat)abstract
- The coagulation of blood plasma and whole blood was studied with a surface plasmon resonance (SPR) based device and a quartz crystal microbalance instrument with energy dissipation detection (QCM-D). The SPR and QCM-D response signals were similar in shape but differing in time scales, reflecting differences in detection mechanisms. The QCM-D response time was longer than SPR, as a physical coupling of the sample to the substrate is required for molecules to be detected by the QCM-method. Change of sample properties within the evanescent field is sufficient for detection with SPR. Both the SPR signals and the QCM-D frequency and dissipation shifts showed dependency on concentrations of coagulation activator and sensitivity to heparin additions. The ratio of dissipation to frequency shifts, commonly considered to reflect viscoelastic properties of the sample, varied with the concentration of activator in blood plasma but not in whole blood. Additions of heparin to the thromboplastin activated whole blood sample, however, made the ratio variation reoccur. Implications of these observations for the understanding of the blood coagulation processes as well as the potential of the two methods in the clinic and in research are discussed.
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