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- Dahlqvist, Per, et al.
(author)
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Environmental enrichment alters nerve growth factor-induced gene A and glucocorticoid receptor messenger RNA expression after middle cerebral artery occlusion in rats
- 1999
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In: Neuroscience. - 1873-7544 .- 0306-4522. ; 93:2, s. 527-535
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Journal article (peer-reviewed)abstract
- Housing rats in an enriched environment after focal brain ischemia improves functional outcome without changes in infarct volume, suggesting neuroplastic changes outside the lesion. In this study, permanent occlusion of the middle cerebral artery was followed by housing in an enriched or a standard environment. Nerve growth factor-induced gene A and glucocorticoid receptor messenger RNA expression were determined by in situ hybridization two to 30 days after middle cerebral artery occlusion. Stroke induced a decrease in nerve growth factor-induced gene A messenger RNA expression in cortical areas outside the ischemic lesion and in the CA1 subregion of the hippocampus two to three days after ischemia. This decrease was more prolonged with environmental enrichment, lasting until 20 days. However, 30 days after focal cerebral ischemia, environmental enrichment increased nerve growth factor-induced gene A expression compared to standard housing. A reduction of hippocampal glucocorticoid receptor (type II) messenger RNA two to 12 days after stroke in standard housed rats was restored by environmental enrichment. These data suggest that improved functional outcome induced by environmental enrichment after middle cerebral artery occlusion is associated with dynamically altered expression of nerve growth factor-induced gene A messenger RNA in brain regions outside the ischemic lesion, and sustained levels of hippocampal glucocorticoid receptor messenger RNA expression.
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| 2. |
- Khayyami, M, et al.
(author)
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Development of an amperometric biosensor based on acetylcholine esterase covalently bound to a new support material
- 1998
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In: Talanta. - 1873-3573. ; 45:3, s. 557-563
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Journal article (peer-reviewed)abstract
- A new type of amperometric biosensor based on immobilised acetylcholine esterase was designed and constructed. The enzyme was immobilised on a flow-through working electrode, which was prepared from reticulated vitreous carbon (RVC) or from a composite material consisting of RVC and superporous agarose. The sensor was operated in FIA mode using acetylthiocholine as a substrate. The sensor responded to inhibitors such as paraoxon—10−9 mol was detected by the sensor in a non-optimised configuration. The practical lifetime of the sensor was at least 1 month.
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| 3. |
- Wikström, Johan, et al.
(author)
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Abdominal vessel enhancement with an ultrasmall, superparamagnetic iron oxide blood pool agent : evaluation of dose and echo time dependence at different field strengths
- 1999
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In: Academic Radiology. - 1076-6332 .- 1878-4046. ; 6:5, s. 292-298
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Journal article (peer-reviewed)abstract
- RATIONALE AND OBJECTIVES: The purpose of the study was to determine the dose and echo time dependence of abdominal vessel enhancement at magnetic resonance (MR) imaging after injection of a blood pool contrast agent at two field strengths. MATERIALS AND METHODS: Sixteen healthy volunteers received NC100150 Injection at three dose levels (1.0 mg, 2.5 mg, and 4.0 mg of iron per kilogram of body weight). Images of the aorta and inferior vena cava (IVC) were obtained at 0.5 or 1.5 T. Four sequences with varying echo times were used with each subject. Signal intensities were recorded from the aorta, IVC, vessel vicinity, air, and a marker outside the patient. Contrast-to-noise ratios (CNRs) were calculated for the vessels. Aortic delineation was subjectively evaluated. RESULTS: Images with the highest mean vessel signal intensities, subjectively assessed as satisfactory for aortic delineation, were obtained with 2.5-4.0 mg of iron per kilogram of body weight at both field strengths. The highest CNR was found with 4.0 mg of iron per kilogram of body weight at 1.5 T. An increase in echo time caused larger signal intensity loss at larger dose levels. The signal intensity from the IVC was higher than that of the aorta at all dose levels, echo times, and field strengths. CONCLUSION: NC100150 Injection is an efficient T1-reducing agent at both 0.5 and 1.5 T. A positive dose response for CNR of the aorta and IVC was seen at 1.5 T.
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| 4. |
- Beland, Marie-Claude, et al.
(author)
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Optical measurement and perception of gloss quality of printed matte-coated paper
- 1998
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In: Proceedings of the International Printing and Graphic Arts Conference. - : CPPA, Montreal, Canada. ; , s. 187-191
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Conference paper (peer-reviewed)abstract
- A set of 32 commercially produced and printed matte-coated papers were rated for gloss quality by a panel of 13 expert judges and light scattering distributions, gloss, and gloss variation measured. Fitting the light scattering distributions to Von Mises distributions, we obtain a factor, kappa, related to the width of the distribution and sensitive to small changes in surface roughness, which relates very well with the subjective rating. Gloss variation in certain surface spatial wavelength bands also correlates well with the gloss quality rating. The topography of the samples was also measured using confocal microscopy and the relationship between light scattering and paper topography is discussed.
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