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- Bergengren, Jakob, et al.
(författare)
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A recent Dreissena invasion in an old canal system in northern Europe
- 2015
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- The Göta Canal was opened in 1832 and connects the Baltic and the Atlantic Sea via the large lakes Vänern and Vättern in south Sweden. Originally used for commercial transport, the canal is today one of the most popular tourist attractions in Sweden with canal cruises, pleasure boating and canoeing. Inventories in 2013 showed that Dreissena mussels recently have invaded lakes, streams and canals in the Motala River drainage basin, i.e. the eastern part of the Göta Canal. According to interviews with local people the mussels may have been there since 2012. During the late summer in 2013 and in 2014 we monitored mussels by scuba diving and we sampled planktonic larval populations in locks and the canal. Dreissena has not dispersed to the western part of the canal system, i.e. west of lake Vättern, where most lakes are oligotrophic with low Ca- andMg-levels. In the eastern part, where several lakes are eutrophic and Ca- and Mg-levels higher, populations have increased very fast. The inventories showed local densities of 10 000 adults m-2 in some eutrophic lakes and larval densities of up to 70 individuals L-1 in the canal water. In Europe, the large range expansion of Dreissena occurred during the late 19th and early 20th century. Why have they dispersed so late into the Göta Canal, i.e. some 170 years after the canal was constructed and some 80 years after they had dispersed to other lakes in Swedennorth of Göta Canal? We can not dismiss dispersal as a a limiting factor but given the historically sustained boat traffic in the region it seems likely that ecological factors may have been important. Freshwaters in Scandinavia are usually low in Ca and Mg and many lakes are characterized by oligotrophic conditions poor in food for filter-feeding Dreissena. In the Göta Canal, changes in biological factors affecting relationships between Dreissena and the regional biota needs to be studied, however. Although we can not explain the delayed invasion we conclude that Dreissena is now established in one of the largest canal system in northern Europe.
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| 2. |
- Leandersson Bogefors, Karolina, et al.
(författare)
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Androgen receptor gene CAG and GGN repeat lengths as predictors of recovery of spermatogenesis following testicular germ cell cancer treatment
- 2017
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Ingår i: Asian Journal of Andrology. - 1008-682X .- 1745-7262. ; 19:5, s. 538-542
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Tidskriftsartikel (refereegranskat)abstract
- Spermatogenesis is an androgen-regulated process that depends on the action of androgen receptor (AR). Sperm production may be affected in men treated for testicular cancer (TC), and it is important to identify the factors influencing the timing of spermatogenesis recovery following cancer treatment. It is known that the CAG and GGN repeat numbers affect the activity of the AR; therefore, the aim of this study is to investigate if the CAG and GGN polymorphisms in the AR gene predict recovery of sperm production after TC treatment. TC patients (n = 130) delivered ejaculates at the following time points: postorchiectomy and at 6, 12, 24, 36, and 60 months posttherapy (T0, T6, T12, T24, T36, and T60). The CAG lengths were categorized into three groups, <22 CAG, 22-23 CAG, and >23 CAG, and the GGN tracts were also categorized into three groups, <23 GGN, 23 GGN, and >23 GGN. At T12, men with 22-23 CAG presented with a statistically significantly (P = 0.045) lower sperm concentration than those with other CAG numbers (8.4 × 10 6 ml-1 vs 16 × 10 6 ml-1 ; 95% CI: 1.01-2.65). This association was robust to omitting adjustment for treatment type and sperm concentration at T0 (P = 0.021; 3.7 × 10 6 ml-1 vs 10 × 10 6 ml-1 ; 95% CI: 1.13-4.90). The same trends were observed for total sperm number. The least active AR variant seems to be associated with a more rapid recovery of spermatogenesis. This finding adds to our understanding of the biology of postcancer therapy recovery of fertility in males and has clinical implications.
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