| 1. |
- Berglund, Olof, et al.
(författare)
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Persistent organic pollutants in river food webs: influence of trophic position and degree of heterotrophy
- 2005
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Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - 1205-7533. ; 62:9, s. 2021-2032
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Tidskriftsartikel (refereegranskat)abstract
- We investigated how the degree of autotrophy/heterotrophy and organism trophic position influenced the bioaccumulation of polychlorinated biphenyls (PCBs) in 10 benthic river food webs consisting of terrestrial detritus, periphyton, invertebrates, and age-0 brown trout (Salmo trutta) in southern Sweden. Concentrations of PCBs increased with trophic position, estimated from delta(15)N and delta(13)C, on a dry weight basis (ng center dot g(-1) dry weight) but not on a lipid weight basis (ng center dot g(-1) lipid). PCB biomagnification factors between the first and second trophic levels (invertebrates/ periphyton and invertebrates/detritus) ranged between 0.3 and 2.3 and between the second and third levels (trout/invertebrates) between 0.3 and 2.0 on a lipid weight basis. The mean proportion of carbon ultimately derived from terrestrial sources, alpha, was 0.82 +/- 0.19 for invertebrates and 0.67 +/- 0.28 for trout. Contrary to our hypothesis, PCB concentrations in trout were positively related to alpha (r(2) = 0.58-0.77, p < 0.05). As alpha and the periphyton density (g C center dot m(-2)) in the rivers was positively related (r(2) = 0.88, p < 0.01), we propose that this relationship was due to an increased retention and exposure of PCBs to trout in rivers with low grazing pressure and high periphyton density.
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| 2. |
- Hallböök, Olof, 1954-, et al.
(författare)
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Safety of the temporary loop ileostomy
- 2002
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Ingår i: Colorectal Disease. - : Wiley. - 1462-8910 .- 1463-1318. ; 4:5, s. 361-364
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Tidskriftsartikel (refereegranskat)abstract
- Objective. To evaluate the complications of the temporary loop ileostomy. Method. A retrospective study of 222 consecutive patients with low anterior resection, ileal pouch-anal anastomosis or continent ileostomy and a diverting loop ileostomy routinely fashioned during the primary operation. The loop ileostomy was closed in 213 patients (96%) during the minimum follow-up period of 15 months. Results. Four patients (2%) required preterm closure of the ostomy due to stomal retraction (n = 3) or bowel obstruction (n = 1). Four patients were readmitted due to transient bowel obstruction that resolved without surgery. After closure of the loop ileostomy a total of 27 patients (13%) had complications. In 7 patients emergency re-operation was done due to small bowel obstruction (n = 5) or intra-abdominal abscess (n = 2). Elective re-operation was done in 5 patients for hernia at the site of the previous stoma. Despite the use of a loop ileostomy there was 1 postoperative death after the initial operation in consequence of anastomotic leakage. There was 1 death in consequence of closure of the loop ileostomy after 3 weeks due to intra-abdominal sepsis and heart failure. Conclusion. In this series closure of the ostomy was associated with one death (0.5%) and overall ostomy-related morbidity included the need to re-operate in 6%.
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| 3. |
- Holmqvist, Niklas, et al.
(författare)
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Lake trophic status and bioaccumulation of polychlorinated biphenyls in benthic organisms: a comparison between littoral and profundal invertebrates
- 2005
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Ingår i: Canadian Journal of Fisheries and Aquatic Sciences. - 1205-7533. ; 62:6, s. 1201-1209
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the influence of lake trophic status on accumulation of polychlorinated biphenyls (PCBs) in littoral and profundal invertebrates from 19 lakes in southern Sweden. The PCB concentration in profundal chironomids (Chironomus sp.) was negatively correlated with lake trophy but the concentration in littoral crayfish (Pacifasticus leniusculus) was unrelated to shifting nutrient regimes. PCB concentrations in chironomids were negatively correlated, while crayfish did not correlate with lake total phosphorus. Two findings indicate that different processes determine bioaccumulation in littoral and profundal invertebrates: (i) a lack of correlation between PCB concentrations in crayfish and chironomids within lakes and (ii) some differences in congener distribution in the two species. We suggest a possible explanation in that chironomids are directly exposed to settling material from the pelagic zone, while crayfish are omnivorous and feed mainly in the littoral zone. A intensive investigation on one pond population could not reveal any individual factors, such as lipid content, size, or sex, influencing bioaccumulation of PCBs in crayfish.
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| 4. |
- Holmqvist, Niklas, et al.
(författare)
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Low levels of persistent organic pollutants (POPS) in New Zealand eels reflect isolation from atmospheric sources
- 2006
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Ingår i: Environmental Pollution. - : Elsevier BV. - 0269-7491. ; 141:3, s. 532-538
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Tidskriftsartikel (refereegranskat)abstract
- Polychlorinated biphenyls (PCBs) and organic pesticides (i.e., DDTs) were measured in long finned eels (Anguilla dieffenbachii) in 17 streams on the west coast of South Island, New Zealand. Very low levels of PCBs and low levels of ppDDE were found. The concentrations of PCBs and ppDDE were not correlated within sites indicating that different processes determined the levels of the two pollutants in New Zealand eels. The PCBs probably originate from atmospheric transport, ppDDE levels are determined by land use and are higher in agriculture areas. The low contamination level of these aquatic systems seems to be a function of a low input from both long and short-range transport as well as few local point sources. No correlation could be found between lipid content and persistent organic pollutants (POPs) concentration (as shown in previous studies) in the eels which could be explained by low and irregular intake of the pollutants.
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| 5. |
- Holmqvist, Niklas, et al.
(författare)
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Persistent organic pollutants (POP) in a benthic omnivore - A comparison between lake and stream crayfish populations
- 2007
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Ingår i: Chemosphere. - : Elsevier BV. - 1879-1298 .- 0045-6535. ; 66:6, s. 1070-1078
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the accumulation of PCB and DDT in crayfish populations in 10 streams in southern Sweden. The results were compared with an earlier study on crayfish in lakes from the same area. We found that the concentration of pollutants in crayfish did not differ between the two types of systems. Variation in body burden was higher in stream living crayfish probably because of the higher influence from pollutants deposited in the catchment area and the more dynamic transport in streams. In streams, pp'-DDE concentrations were positively correlated to trophic status (total phosphorous) while PCB did not show any correlation with the nutrient regime. Further, mean Sigma PCB and p,p'-DDE concentrations in crayfish did not correlate in streams. We suggest that the sources of the two pollutants differ for stream living crayfish. The results indicate that crayfish in streams are affected to a higher degree to pollutants in the catchment area and the precipitation regime. In lakes, internal processes govern uptake of pollutants in crayfish.
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| 6. |
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| 7. |
- Larsson, Per, et al.
(författare)
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Heavy metals and stable isotopes in a benthic omnivore in a trophic gradient of lakes
- 2007
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Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 1520-5851 .- 0013-936X. ; 41:17, s. 5973-5979
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Tidskriftsartikel (refereegranskat)abstract
- Heavy metals (Cd, Hg, and Pb) and stable isotopes (N-15, C-13) in crayfish (Pacifastacus leniusculus) were studied in a trophic gradient of lakes (N = 19) in southern Sweden. Trophic indicators of the lakes as total phosphorus (tot-P) varied from 5 to 93 mu g/L. The examined lakes had no known point sources of heavy metals, but the catchment areas varied from mainly forested to agricultural land. Cd and Hg in crayfish were affected by the trophic status of the lakes, showing significant negative relationship with tot-P, total nitrogen, and chlorophyll A content and a positive relationship with lake transparency (Secchi depth). The concentration of these two heavy metals was thus higher in crayfish in the oligotrophic lakes and decreased linearly to the eutrophic ones. Pb was not related to any lake variable. Stable isotopes of carbon (delta C-13) and nitrogen (615N) in crayfish were a reflection of that found in the sediment as shown by positive linear relationships for the lakes. In the sediment of the lakes, delta C-13 signature showed significant negative relationships with the trophic indicators but positive results were shown for lake transparency. The trophic gradient of the lakes was reflected by delta C-13 in the sediment and in the crayfish. 615N in crayfish was a reflection of 615N in the sediment but the relationship was not coupled to the trophic statue of the lakes. The results from the study show that Cd and Hg in benthic omnivores as crayfish are affected by ecological processes in lakes, such as eutrophication. Stable isotopes, such as 13C and 15 N, can be used to study these ecological processes.
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| 8. |
- Machado, Mikael, et al.
(författare)
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Defunctioning stoma in low anterior resection with colonic pouch for rectal cancer : A comparison between two hospitals with a different policy
- 2002
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Ingår i: Diseases of the Colon & Rectum. - : Ovid Technologies (Wolters Kluwer Health). - 0012-3706 .- 1530-0358. ; 45:7, s. 940-945
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE: The aim of this study was to compare surgical outcome, after low anterior resection for rectal cancer with colonic J-pouch, at two departments with a different policy regarding the use of a routine diverting stoma. METHODS: A total of 161 consecutive patients with invasive rectal carcinomas operated on between 1990 and 1997 with a total mesorectal excision and a colonic J-pouch were included in the study. Eighty patients were operated on in a surgical unit using routine defunctioning stomas (96 percent), whereas 81 were operated on in a department in which diversion was rarely used (5 percent). Recorded data with respect to surgical outcome were analyzed and compared. RESULTS: There was no difference between the two centers in postoperative mortality in connection with the primary resection and subsequent stoma reversal (3.7 vs. 3.8 percent). No significant difference could be found in the number of patients with pelvic sepsis (anastomotic leaks, 9 vs. 12 percent). Surgical outcome in patients with pelvic sepsis was also similar. The frequency of reoperations associated with the anterior resection and subsequent stoma reversal was identical (14 percent). The total hospital stay (primary operation and stoma reversal) was significantly longer with than without a routine stoma (17 (range, 2-59) vs. 12 (range, 5-55) days, respectively, P < 0.001). CONCLUSION: This study suggests that the routine use of diversion does not protect the patient from anastomotic complications or pelvic sepsis and its use requires a second admission for closure.
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| 9. |
- Morren, Geert, et al.
(författare)
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Audit of anal-sphincter repair
- 2001
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Ingår i: Colorectal Disease. - : Wiley. - 1462-8910 .- 1463-1318. ; 3:1, s. 17-22
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Tidskriftsartikel (refereegranskat)abstract
- ObjectiveStructural damage of the anterior part of the anal sphincter is a major cause of faecal incontinence. Sphincter repair is the standard surgical treatment. This study was designed to analyse the results of anal sphincter repair, to identify possible predictors of outcome and to investigate the presence of bowel symptoms other than leakage at follow up.Patients and methodsFifty-five women (median age 39 years, range 24–73 years) who underwent anal sphincter repair between 1986 and 1997 at the University Hospital of Linköping answered a postal questionnaire. Current bowel function, degree of continence and the patients’ functional result as worse, unchanged, some improvement, good or excellent were assessed. Good or excellent function was regarded as a successful result, the rest as failure. Age, duration of symptoms, type of surgery, morbidity and length of follow up were analysed in relation to outcome. Results of pre- and post-operative anal manometry, endoanal ultrasound, anal sphincter electromyography and pudendal nerve function were also analysed.ResultsAfter a median (range) follow-up period of 40 months (5–137) months, 31 (56%) patients rated the result as either excellent (n=10) or good (n=21). Twenty-one (38%) patients rated the result as some improvement (n=14), unchanged (n=6) or worse (n=1). In three (5%) patients a colostomy was fashioned because of failure. Patients >50 years at surgery (n=18) had a worse outcome (P=0.001). Successful outcome was correlated to increased squeeze pressures post-operatively. The presence of post-operative urgency (P=0.01) and loose stools (P=0.02) was more common in patients with poor outcome. Eight patients became continent to formed and liquid stool.
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| 10. |
- Nyström, Per, et al.
(författare)
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Crayfish in lakes and streams: individual and population responses to predation, productivity and substratum availability
- 2006
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Ingår i: Freshwater Biology. - : Wiley. - 0046-5070 .- 1365-2427. ; 51:11, s. 2096-2113
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Tidskriftsartikel (refereegranskat)abstract
- 1. In a correlative study, we investigated the relative importance of fish predation, refuge availability and resource supply in determining the abundance and size distributions of the introduced and omnivorous signal crayfish (Pacifastacus leniusculus) in lakes and streams. Moreover, the biomass and food selection of predatory fish was estimated in each habitat type and stable isotopes of carbon and nitrogen were measured in perch (Perca fluviatilis), the dominant predator in the lakes, and in its potential food sources (crayfish, juvenile roach and isopods). 2. In lakes, crayfish were the most frequent prey in large perch (46%), followed by other macroinvertebrates (26%, including the isopod Asellus aquaticus) and small fish (25%). Crayfish and fish dominated the gut contents of large perch with respect to biomass. Nitrogen signatures showed that perch were one trophic level above crayfish (approx. 3.4 parts per thousand) and a two-source mixing model using nitrogen isotope values indicated that crayfish (81%) contributed significantly more to perch isotope values than did juvenile roach (19%). A positive correlation was found between the abundance of crayfish and the biomass of large perch. Crayfish abundance in lakes was also positively correlated with the proportion of cobbles in the littoral zone. Lake productivity (chlorophyll a) was positively correlated with crayfish size, but not with crayfish abundance. 3. In streams, brown trout (Salmo trutta) were the most abundant predatory fish. Gut contents of large trout in a forested stream showed that terrestrial insects were the most frequently found prey (60%), followed by small crayfish (27%) and isopods (27%). In contrast to lakes, the relative abundance of crayfish was negatively correlated with the total biomass of predatory fish and with total biomass of trout. However, abundance of crayfish at sites with a low biomass of predatory fish varied considerably and was related to substratum grain size, with fewer crayfish being caught when the substratum was sandy or dominated by large boulders. The mean size of crayfish was greater at stream sites with a high standing stock of periphyton, but neither predator biomass nor substratum grain size was correlated with crayfish size. 4. Our results suggest that bottom-up processes influence crayfish size in lakes and streams independent of predator biomass and substratum availability. However, bottom-up processes do not influence crayfish abundance. Instead, substratum availability (lakes) and interactions between predation and substratum grain size (streams) need to be considered in order to predict crayfish abundance.
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