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- Carlström, Mattias, 1978-
(author)
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Development of Salt-Sensitive Hypertension in Hydronephrosis
- 2008
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Doctoral thesis (other academic/artistic)abstract
- Hydronephrosis, due to ureteropelvic junction obstruction, is a common condition in infants with an incidence of approximately 0.5-1%. During the last decade, the surgical management of non-symptomatic hydronephrosis has become more conservative, and the long-term physiological consequences of this new policy are unclear. The overall aim of this thesis was to determine whether there is a link between hydronephrosis and the development of hypertension. Hydronephrosis was induced by partial ureteral obstruction in 3-week old rats or mice. In the adult animals, blood pressure was measured telemetrically during different sodium conditions and the renal function was evaluated. Both species developed salt-sensitive hypertension and histopathological changes (i.e. fibrosis, inflammation, glomerular and tubular changes) that correlated with the degree of hydronephrosis. An abnormal renal excretion pattern with increased diuresis and impaired urine concentrating ability was observed in hydronephrosis. The mechanisms were primarily located to the diseased kidney, as relief of the obstruction attenuated blood pressure and salt-sensitivity. Increased renin angiotensin system activity, due to ureteral obstruction, might be involved in the development but not necessary the maintenance of hypertension. Hydronephrotic animals displayed reduced nitric oxide availability, which might be due to increased oxidative stress in the diseased kidney. Renal nitric oxide deficiency and subsequent resetting of the tubuloglomerular feedback mechanism, appeared to have an important role in the development of hypertension. In conclusion, experimental hydronephrosis, induced by partial ureteral obstruction, provides a new model for studies of salt-sensitive hypertension. Furthermore, the new findings imply that the current conservative treatment strategy in hydronephrosis should be reconsidered in favour of treatment that is more active, in order to prevent the development of renal injury and hypertension in later life.
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| 2. |
- Moksnes, Per-Olav, et al.
(author)
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Fritidsbåtars påverkan på grunda kustekosystem i Sverige
- 2019
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Reports (other academic/artistic)abstract
- Sweden has a long and beautiful coastline with extensive archipelagos that offer exceptional conditions for recreational boating. There are more than 700 000 recreational boats in Sweden, which is one of the highest numbers in the world in relation to the population size. Small tidal differences and many sheltered bays also provide good conditions for storing boats at docks and piers and jetties. As a result, large areas of the Swedish coast are today covered with docks and marinas for recreational boats. The large number of boats and docks could have substantial negative effects on the environment. However, the understanding of the cumulative impact of recreational boating on Swedish coastal ecosystem has so far been incomplete. The goal with this report from the Swedish Institute for the Marine Environment has been to compile and summarize the present state of knowledge regarding how recreational boating affect shallow coastal ecosystems in Sweden, to determine the extent of the impact and if the development is sustainable. The aim has been to present scientific knowledge on these topics in an accessible way in order to facilitate the development of a more sustainable management of recreational boating in Sweden.The scientific literature strongly support that recreational boating generates many negative effects on the marine environment. Recreational boating requires a number of physical structures and generate a number activities that each results in several different pressures on the environment. An increased number of marinas, docks and dredged canals results in losses of important habitats, as well as long-term deterioration of the environmental conditions locally. Dredging and dumping of dredge material results in increased turbidity and dispersal of sediment, nutrients and pollutants over large areas with negative effects on many aquatic organisms, e.g. vegetation, fishes and mussels. Traffic from recreational boats and anchoring result in increased turbidity and sediment erosion as well as damage to habitats. Motor boats also create underwater noise that can disturb e.g. fishes, seals and porpoises. In addition, recreational boating result in substantial emissions of toxic substances and pollution from e.g. antifouling paint and combustion engines.More than 60% of all docks and marinas are found in wave sheltered, shallow (<3 m) areas with soft bottoms, despite that this environment only constitute 25% of shallow coastal areas in Sweden. These sheltered areas are well suited for storing boats, but also constitute one of the most productive and valuable environments along the coast. They are important environments for vegetation such as seagrass, pondweed and stoneworts, which in turn constitute important spawning and nursery areas for a large number of fish and invertebrates. The report shows that these shallow soft bottom environments are very sensitive to a majority of the stressors that recreational boating generate. Boating therefore create a disproportionally large impact on environments with high values.Although the impact from a single recreational boat or dock is limited, the cumulative effect is substantial because of the sheer number. According to recent inventories, there are today almost 110 000 docks along the Swedish coast covering almost 2 000 km of bottom. In comparison with the 1960s, the amount of docks has increased with almost 160%, which today constitutes an increase of 1 700 new docks per year. Recent studies show that vegetation is degraded as the number of docks and boats increase within shallow, wave sheltered areas. It is estimated that almost 20% of this important environment is negatively affected by recreational boating today; in the County of Stockholm and Västra Götaland around 30% of shallow, wave sheltered areas are estimated to be impacted. Despite several management measures in the last decades to decrease coastal exploitation, there are no signs that the rate of exploitation is decreasing.The large number of recreational boats with combustion engines, the trend of increasing engine size, and the fact that engines lack all forms of emission control result in substantial emissions of pollutants and greenhouse gases. Recent estimates suggest that the emissions from recreational boats are very high and comparable with other types of transport in Sweden. Emission of toxic copper from antifouling paint on recreational boats is also substantial and contributes to the high levels of copper in coastal waters, which is above the limit for good ecological status in 85% of the assessed coastal water bodies.Although most boat owners likely spend time at sea because they enjoy and care about the environment, the results presented in this report show that recreational boating have a substantial negative impact on the coastal environment, particularly in shallow, wave protected areas. In these areas, today’s use and development of recreational boating cannot be considered sustainable. However, the report also shows that there are ways to decrease the environmental impact from recreational boating. By changing the way we use and store recreational boats, and by improving management we can still allow coming generations to enjoy unexploited coastal environments with clear water and a rich plant and animal life.The report ends by discussing new, possible measures and solutions for a more sustainable use of recreational boats in Sweden, which could be a starting point for continuing such work. These include e.g. to identify vulnerable coastal environments in order to steer away exploitation and recreational boat traffic from these areas. By storing boats on land, the need for docks, dredging and toxic antifouling paint could decrease. Reduced speed limits and access limitations for recreational motorboats in certain areas could decrease negative impact on the most vulnerable habitats. Finally, new, environmentally friendly technology, and new financial instruments could be used to decrease negative impacts and create a more sustainable development of recreational boating.
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