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| 2. |
- Arnell, Robert, et al.
(författare)
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Analytical Characterization of Chiral Drug-Protein Interactions: Comparison between the Optical Biosensor (Surface Plasmon Resonance) Assay and the HPLC Perturbation Method
- 2006
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Ingår i: Analytical Chemistry. ; 78:5, s. 1682-1689
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Tidskriftsartikel (refereegranskat)abstract
- Two modern, fundamentally different methods were used for a detailed investigation of enantioselective drug-protein interactions, a surface plasmon resonance (SPR)-based Biacore 2000 biosensor assay and the previously validated HPLC perturbation method (HPLC-PM). This is the first time SPR has been used for this purpose. The fundamental features of the two methods were investigated, and the consequences for operation and data evaluation were addressed. With HPLC-PM, chiral data could be obtained directly from the racemic mixture, whereas a separate analysis of each pure enantiomer was required to obtain chiral data with SPR. It was shown that if chirality is not attributed in the SPR analysis, misleading average racemic binding constants will be obtained. Both drug and protein consumption were considerably higher with HPLC-PM. HPLC-PM was found to be best suited for measurements of weak affinity interactions, whereas the SPR method was best for strong interactions. With both methods, the presence of DMSO in the samples severely affected the interactions, introducing errors. The binding of the -blockers alprenolol and propranolol to Cel7a cellulase was used as a model system. These methods gave results that agreed quite well qualitatively, but considerable quantitative deviations were sometimes obtained.
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| 3. |
- Brena, Beatriz M., et al.
(författare)
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ITREOH building of regional capacity to monitor recreational water : development of a non-commercial microcystin ELISA and its impact on public health policy
- 2006
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Ingår i: International journal of occupational and environmental health. - 1077-3525 .- 2049-3967. ; 12:4, s. 377-385
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Tidskriftsartikel (refereegranskat)abstract
- In 2001, a University of California, Davis-University of the Republic, Montevideo, partnership created a Fogarty ITREOH program to exploit the potential of ELISA to provide a low-cost environmental analysis attractive to economically distressed countries of temperate South America. This paper describes the development and validation of an ELISA method for the determination of Cyanobacteria microcystin toxins in algal blooms, which release hepatotoxic metabolites that can reach toxic levels in rivers, lakes, or coastal estuaries used for recreation or water supplies. The assay made possible the first systematic monitoring of water from the Rio de la Plata at Montevideo over two summers. The project has been integrated into a bi-national effort to monitor the Rio de la Plata.
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| 4. |
- Ferraz, Natalia, et al.
(författare)
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Influence of nanoporesize on platelet adhesion and activation
- 2008
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 19:9, s. 3115-21
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Tidskriftsartikel (refereegranskat)abstract
- In this study we have evaluated the influence of biomaterial nano-topography on platelet adhesion and activation. Nano-porous alumina membranes with pore diameters of 20 and 200 nm were incubated with whole blood and platelet rich plasma. Platelet number, adhesion and activation were determined by using a coulter hematology analyzer, scanning electron microscopy, immunocytochemical staining in combination with light microscopy and by enzyme immunoassay. Special attention was paid to cell morphology, microparticle generation, P-selectin expression and beta-TG production. Very few platelets were found on the 200 nm alumina as compared to the 20 nm membrane. The platelets found on the 20 nm membrane showed signs of activation such as spread morphology and protruding filipodia as well as P-selectin expression. However no microparticles were detected on this surface. Despite the fact that very few platelets were found on the 200 nm alumina in contrast to the 20 nm membrane many microparticles were detected on this surface. Interestingly, all microparticles were found inside circular shaped areas of approximately 3 mum in diameter. Since this is the approximate size of a platelet we speculate that this is evidence of transient, non-adherent platelet contact with the surface, which has triggered platelet microparticle generation. To the authors knowledge, this is the first study that demonstrates how nanotexture can influence platelet microparticle generation. The study highlights the importance of understanding molecular and cellular events on nano-level when designing new biomaterials.
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| 5. |
- Ferraz, Natalia, et al.
(författare)
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Nanoporesize affects complement activation
- 2008
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Ingår i: Journal of biomedical materials research. Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 87:3, s. 575-81
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Tidskriftsartikel (refereegranskat)abstract
- In the present study, we have shown the vast importance of biomaterial nanotexture when evaluating inflammatory response. For the first time in an in vitro whole blood system, we have proven that a small increase in nanoporesize, specifically 180 nm (from 20 to 200 nm), has a huge effect on the complement system. The study was done using nanoporous aluminiumoxide, a material that previously has been evaluated for potential implant use, showing good biocompatibility. This material can easily be manufactured with different pore sizes making it an excellent candidate to govern specific protein and cellular events at the tissue-material interface. We performed whole blood studies, looking at complement activation after blood contact with two pore size alumina membranes (pore diameters, 20 and 200 nm). The fluid phase was analyzed for complement soluble components, C3a and sC5b-9. In addition, surface adsorbed proteins were eluted and dot blots were performed to detect IgG, IgM, C1q, and C3. All results point to the fact that 200 nm pore size membranes are more complement activating. Significantly, higher values of complement soluble components were found after whole blood contact with 200 nm alumina and all studied proteins adsorbed more readily to this membrane than to the 20 nm pore size membrane. We hypothesize that the difference in complement activation between our two test materials is caused by the type and the amount of adsorbed proteins, as well as their conformation and orientation. The different protein patterns created on the two alumina membranes are most likely a consequence of the material topography.
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| 8. |
- Ferraz-Nunes, Jose, 1947
(författare)
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Cost-effective prevention of hip fractures
- 2005
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Ingår i: International Advances in Economic Research. - 1083-0898 .- 1573-966X. ; 11:1, s. 49-67
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Tidskriftsartikel (refereegranskat)abstract
- The main objective of the analysis in this article is to do a health economic study of a preventive program that may influence the risk of hip fractures for people age 65 and older. The analysis of health promoting measures aimed at the prevention of hip fractures shows that there is a large potential for reducing costs and achieving significant health benefits within the older groups of the population. Prevention of hip fractures in the "best cities" seems to be cost-effective because it dominates a situation without any prevention. This implies a reduction in the total costs for society and an improvement in the quality of life and life expectancy.
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