| 1. |
- Birks, H.H., et al.
(författare)
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The Kråkenes Late-glacial Palaeoenvironmental Project.
- 1996
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Ingår i: Journal of Paleolimnology. - 0921-2728 .- 1573-0417. ; 15:3, s. 281-286
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Tidskriftsartikel (refereegranskat)abstract
- Krakenes is the site of a small lake on the west coast of Norway that contains a long sequence of late-glacial sediments. The Younger Dryas is well represented, as a cirque glacier developed in the catchment at this time. This site offers unique opportunities to reconstruct late-glacial environments from independent sources of evidence; physical evidence (glacial geomorphology, sedimentology, palaeomagnetism, radiocarbon dating), and biological evidence from the remains of animals and plants derived from both the terrestrial and aquatic ecosystems. This report describes the background to the site, and the international multidisciplinary project to reconstruct late-glacial and early Holocene environmental and climatic changes at Krakenes.
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| 2. |
- Birks, H.H., et al.
(författare)
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The development of the aquatic ecosytem at Kråkenes Lake, western Norway, during the late glacial and early Holocene - a synthesis.
- 2000
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Ingår i: Journal of Paleolimnology. - 0921-2728 .- 1573-0417. ; 23:1, s. 91-114
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Tidskriftsartikel (refereegranskat)abstract
- This paper synthesises the palaeoecological reconstructions, including palaeoclimatic inferences, based on the available fossil record of plants (pollen, macrofossils, mosses, diatoms) and animals (chironomids, Cladocera, Coleoptera, Trichoptera, oribatid mites) in the late-glacial and early-Holocene sediments of Kråkenes Lake, western Norway, with special emphasis on changes in the aquatic ecosystem. New percentage and influx pollen diagrams for selected taxa provide insights into the terrestrial setting. The information from all the proxies is collated in a stratigraphical chart, and the inferred changes in the lake and its catchment are discussed. The individual fossil sequences are summarised by detrended correspondence analysis (DCA), and sample scores on the first DCA axes are plotted against an estimated calendar-year timescale for comparison of the timing and magnitude of changes in assemblage composition. The DCA plots show that the large late-glacial biotic changes were synchronous, and were driven by the overriding forcing factor of temperature. During the early Holocene, however, the changes in different groups were more gradual and were independent of each other, showing that other factors were important and interactive, such as the inwash of dissolved and particulate material from the catchment, the base and nutrient status of the lake-water, and the internal processes of ecosystem succession and sediment accumulation. This multi-disciplinary study, with proxies for changes in the lake and in the catchment, highlights the dependence of lake biota and processes not only on regional climatic changes but also on changes in the lake catchment and on internal processes within the lake. Rates of change for each group are also estimated and compared. The reaction times to the sharp temperature changes at the start and end of the Younger Dryas were very rapid and occurred within a decade of the temperature change. Aquatic organisms tracked the temperature and environmental changes very closely, and are probably the best recorders of late-glacial climatic change in the fossil record.
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| 3. |
- Pessah-Rasmussen, H, et al.
(författare)
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Glutathione transferase activity in human vessels and in cultured arterial smooth muscle cells
- 1993
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Ingår i: International Angiology. - 0392-9590. ; 12:4, s. 54-348
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Tidskriftsartikel (refereegranskat)abstract
- Glutathione transferases play an important role in the detoxification of many different endogeneous and exogenous compounds such as metabolites of polycyclic aromatic hydrocarbons (PAH) of cigarette tar. There is evidence that PAH may be atherogenic. The glutathione transferase activity towards trans-stilbene oxide (GST-tSBO) can be separated in blood in GST-positive and GST-negative phenotypes. We have previously suggested that the GST-negative phenotype may be associated with a higher morbidity in intermittent claudication among middle aged smokers. In the present study, GST-tSBO could easily be measured in human, rabbit and bovine arterial smooth muscle cells (SMC) in culture. The level of GST-tSBO was higher in rabbit than in bovine SMC. It was stable in bovine SMC during 5 cell passages and it could be induced twofold by long-time incubation with dimethylsulfoxide-soluble particulate matter from cigarette smoke or 3,4-benzo(a)pyrene. There was a positive correlation between the level of GST-tSBO in blood and in "healthy" arterial and venous tissue from individuals operated with coronary bypass. The enzyme levels in arterial tissue were lower than in venous tissue. GST-tSBO in atherosclerotic segments of human arteries was lower than in "healthy" segments from the same artery. These findings suggest that the arterial wall may have a low defense against toxic compounds that may decrease further as atherosclerosis proceeds. It is concluded that SMC are suitable for the study of the effects of PAH in relation to GST-tSBO and that the enzyme activity in blood will reflect the individual GST-tSBO phenotype also in vascular tissues.
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| 4. |
- Pessah-Rasmussen, H, et al.
(författare)
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Lack of glutathione transferase activity in intermittent claudication
- 1990
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Ingår i: International Angiology. - 0392-9590. ; 9:2, s. 4-70
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Tidskriftsartikel (refereegranskat)abstract
- Glutathione transferase activity towards trans-stilbene oxide (GT-tSBO), an enzyme involved in the detoxification of many substances such as polycyclic aromatic hydrocarbons, was studied in 77 consecutive patients operated with coronary bypass, 73 patients with intermittent claudication, 78 healthy smokers and in 38 healthy non-smokers. The mean ages of these groups were similar. Lack of GT-tSBO was recorded in 45% of coronary bypass patients, in 39% of smoking coronary bypass patients, in 61% of patients with intermittent claudication, in 41% of healthy smokers and in 31% of healthy non-smokers. The lack of GT-tSBO was significantly more frequent among patients with intermittent claudication compared to healthy non-smokers (p less than 0.01) and healthy smokers (p less than 0.025) and to smoking coronary bypass. It is concluded that the lack of GT-tSBO is found more frequently among patients with intermittent claudication and this might contribute to explain the sensitivity to smoking among these subjects.
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