| 45041. |
- Knutsen, Helle Katrine, et al.
(författare)
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Risk for animal and human health related to the presence of dioxins and dioxin-like PCBs in feed and food.
- 2018
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Ingår i: EFSA journal. European Food Safety Authority. - : Wiley. - 1831-4732. ; 16:11
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Tidskriftsartikel (refereegranskat)abstract
- The European Commission asked EFSA for a scientific opinion on the risks for animal and human health related to the presence of dioxins (PCDD/Fs) and DL-PCBs in feed and food. The data from experimental animal and epidemiological studies were reviewed and it was decided to base the human risk assessment on effects observed in humans and to use animal data as supportive evidence. The critical effect was on semen quality, following pre- and postnatal exposure. The critical study showed a NOAEL of 7.0 pg WHO2005-TEQ/g fat in blood sampled at age 9 years based on PCDD/F-TEQs. No association was observed when including DL-PCB-TEQs. Using toxicokinetic modelling and taking into account the exposure from breastfeeding and a twofold higher intake during childhood, it was estimated that daily exposure in adolescents and adults should be below 0.25 pg TEQ/kg bw/day. The CONTAM Panel established a TWI of 2 pg TEQ/kg bw/week. With occurrence and consumption data from European countries, the mean and P95 intake of total TEQ by Adolescents, Adults, Elderly and Very Elderly varied between, respectively, 2.1 to 10.5, and 5.3 to 30.4 pg TEQ/kg bw/week, implying a considerable exceedance of the TWI. Toddlers and Other Children showed a higher exposure than older age groups, but this was accounted for when deriving the TWI. Exposure to PCDD/F-TEQ only was on average 2.4- and 2.7-fold lower for mean and P95 exposure than for total TEQ. PCDD/Fs and DL-PCBs are transferred to milk and eggs, and accumulate in fatty tissues and liver. Transfer rates and bioconcentration factors were identified for various species. The CONTAM Panel was not able to identify reference values in most farm and companion animals with the exception of NOAELs for mink, chicken and some fish species. The estimated exposure from feed for these species does not imply a risk.
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| 45042. |
- Knutsen, Helle Katrine, et al.
(författare)
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Risk to human health related to the presence of perfluorooctane sulfonic acid and perfluorooctanoic acid in food.
- 2018
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Ingår i: EFSA journal. European Food Safety Authority. - : Wiley. - 1831-4732. ; 16:12
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Tidskriftsartikel (refereegranskat)abstract
- The European Commission asked EFSA for a scientific evaluation on the risks to human health related to the presence of perfluorooctane sulfonic acid (PFOS) and perfluorooctanoic acid (PFOA) in food. Regarding PFOS and PFOA occurrence, the final data set available for dietary exposure assessment contained a total of 20,019 analytical results (PFOS n = 10,191 and PFOA n = 9,828). There were large differences between upper and lower bound exposure due to analytical methods with insufficient sensitivity. The CONTAM Panel considered the lower bound estimates to be closer to true exposure levels. Important contributors to the lower bound mean chronic exposure were 'Fish and other seafood', 'Meat and meat products' and 'Eggs and egg products', for PFOS, and 'Milk and dairy products', 'Drinking water' and 'Fish and other seafood' for PFOA. PFOS and PFOA are readily absorbed in the gastrointestinal tract, excreted in urine and faeces, and do not undergo metabolism. Estimated human half-lives for PFOS and PFOA are about 5 years and 2-4 years, respectively. The derivation of a health-based guidance value was based on human epidemiological studies. For PFOS, the increase in serum total cholesterol in adults, and the decrease in antibody response at vaccination in children were identified as the critical effects. For PFOA, the increase in serum total cholesterol was the critical effect. Also reduced birth weight (for both compounds) and increased prevalence of high serum levels of the liver enzyme alanine aminotransferase (ALT) (for PFOA) were considered. After benchmark modelling of serum levels of PFOS and PFOA, and estimating the corresponding daily intakes, the CONTAM Panel established a tolerable weekly intake (TWI) of 13 ng/kg body weight (bw) per week for PFOS and 6 ng/kg bw per week for PFOA. For both compounds, exposure of a considerable proportion of the population exceeds the proposed TWIs.
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| 45043. |
- Knutsen, H. R., et al.
(författare)
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Fish welfare, fast muscle cellularity, fatty acid and body-composition of juvenile spotted wolffish (Anarhichas minor) fed a combination of plant proteins and microalgae (Nannochloropsis oceanica)
- 2019
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Ingår i: Aquaculture. - : Elsevier BV. - 0044-8486. ; 506, s. 212-223
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Tidskriftsartikel (refereegranskat)abstract
- Spotted wolffish (Anarhichas minor) is a promising candidate for diversification of cold-water aquaculture. An increased knowledgebase is needed concerning the capacity of spotted wolffish to utilize a variety of feed ingredients such as microalgae and terrestrial plants. The aim of the study was therefore to investigate the effect of incorporating graded levels of microalgae (Nannochloropsis oceanica) on fish welfare indicators (growth, hepasomatic index, hematological parameters), fast muscle cellularity, chemical and fatty acid composition. Three isonitrogenous and isocaloric diets were formulated; one control diet (0% N. oceanica) and two diets with low (7.5% N. oceanica) and high (15% N. oceanica) levels of microalgae replacing fishmeal and wheat in the diets. After 12 weeks of feeding, the fish showed low growth compared to previous wolffish studies (0.26% SGR). However, this effect was not treatment dependent as there were no differences in growth or fast muscle cellularity among the three treatment groups and hematological parameters showed no indications of stress in the fish fed microalgae. Hepatosomatic index decreased over the course of the experiment for all treatment groups; a significantly larger reduction was noted in the algae-fed fish compared to the control. The omega-3 fatty acid EPA increased in the whole body of the fish fed diets containing microalgae. The results suggest that spotted wolffish has potential to utilize inclusions of up to 15% of the microalgae N. oceanica.
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| 45044. |
- Knutsen, H., et al.
(författare)
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Stable coexistence of genetically divergent Atlantic cod ecotypes at multiple spatial scales
- 2018
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Ingår i: Evolutionary Applications. - : Wiley. - 1752-4571. ; 11:9, s. 1527-1539
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Tidskriftsartikel (refereegranskat)abstract
- Coexistence in the same habitat of closely related yet genetically different populations is a phenomenon that challenges our understanding of local population structure and adaptation. Identifying the underlying mechanisms for such coexistence can yield new insight into adaptive evolution, diversification and the potential for organisms to adapt and persist in response to a changing environment. Recent studies have documented cryptic, sympatric populations of Atlantic cod (Gadus morhua) in coastal areas. We analysed genetic origin of 6,483 individual cod sampled annually over 14 years from 125 locations along the Norwegian Skagerrak coast and document stable coexistence of two genetically divergent Atlantic cod ecotypes throughout the study area and study period. A "fjord" ecotype dominated in numbers deep inside fjords while a "North Sea" ecotype was the only type found in offshore North Sea. Both ecotypes coexisted in similar proportions throughout coastal habitats at all spatial scales. The size-at-age of the North Sea ecotype on average exceeded that of the fjord ecotype by 20% in length and 80% in weight across all habitats. Different growth and size among individuals of the two types might be one of several ecologically significant variables that allow for stable coexistence of closely related populations within the same habitat. Management plans, biodiversity initiatives and other mitigation strategies that do not account for the mixture of species ecotypes are unlikely to meet objectives related to the sustainability of fish and fisheries.
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| 45045. |
- Knutsen, H., et al.
(författare)
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Transport of North Sea cod larvae into the Skagerrak coastal populations
- 2004
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Ingår i: Proceedings of the Royal Society of London Series B-Biological Sciences. - : The Royal Society. - 0962-8452 .- 1471-2954. ; 271:1546, s. 1337-1344
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Tidskriftsartikel (refereegranskat)abstract
- The Atlantic cod (Gadus morhua) is economically one of the world's most important marine species-a species presently suffering from heavy overexploitation throughout its range of distribution. Although not fully understood, the Atlantic cod is believed to be structured into populations in a rather complex manner, whereby both highly migratory and more confined ocean-spawning stocks coexist with stationary coastal populations. Owing to the complex population structure, little is presently known about how overexploitation of offshore stocks may affect other segments of the species. Here, we use microsatellite DNA analyses of coastal and offshore cod in combination with oceanographic modelling to investigate the population structure of Atlantic cod in the North Sea-Skagerrak area and evaluate the potential for larval transport into coastal populations. Our results suggest an extensive but temporally variable drift of offshore cod larvae into coastal populations. In a year (2001) with high inflow of North Sea waters into the Skagerrak we find that juvenile cod caught along the Skagerrak coast are predominantly of North Sea origin, whereas in a year (2000) with low inflow juveniles appear to be of local origin. These findings indicate that offshore cod may influence coastal cod populations over large distances.
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| 45046. |
- Knutsen, Jon Halvor, et al.
(författare)
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Stress-induced inhibition of translation independently of eIF2α phosphorylation
- 2015
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Ingår i: Journal of Cell Science. - : The Company of Biologists. - 0021-9533 .- 1477-9137. ; 128:23, s. 4420-4427
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Tidskriftsartikel (refereegranskat)abstract
- Exposure of fission yeast cells to ultraviolet (UV) light leads to inhibition of translation and phosphorylation of the eukaryotic initiation factor-2α (eIF2α). This phosphorylation is a common response to stress in all eukaryotes. It leads to inhibition of translation at the initiation stage and is thought to be the main reason why stressed cells dramatically reduce protein synthesis. Phosphorylation of eIF2α has been taken as a readout for downregulation of translation, but the role of eIF2α phosphorylation in the downregulation of general translation has not been much investigated. We show here that UVinduced global inhibition of translation in fission yeast cells is independent of eIF2α phosphorylation and the eIF2α kinase general control nonderepressible-2 protein (Gcn2). Also, in budding yeast and mammalian cells, the UV-induced translational depression is largely independent of GCN2 and eIF2α phosphorylation. Furthermore, exposure of fission yeast cells to oxidative stress generated by hydrogen peroxide induced an inhibition of translation that is also independent of Gcn2 and of eIF2α phosphorylation. Our findings show that stress-induced translational inhibition occurs through an unknown mechanism that is likely to be conserved through evolution.
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| 45047. |
- Knutsen, Maja, et al.
(författare)
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Oxygenated Nanocellulose - A Material Platform for Antibacterial Wound Dressing Devices
- 2021
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Ingår i: ACS Applied Bio Materials. - : American Chemical Society. - 2576-6422. ; 4:10, s. 7554-7562
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Tidskriftsartikel (refereegranskat)abstract
- Both carboxylated cellulose nanofibrils (CNF) and dissolved oxygen (DO) have been reported to possess antibacterial properties. However, the combination for use as wound dressings against biofilm infections in chronic wounds is less known. The present study reports the development of oxygenated CNF dispersions that exhibit strong antibacterial effect. Carboxylated CNF dispersions with different oxidation levels were oxygenated by the OXY BIO System and tested for antibacterial activity against Pseudomonas aeruginosa and Staphylococcus aureus. The results reveal that the higher oxidation level of the CNFs, the better antibacterial effect. Scanning electron microscopy of bacterial biofilms revealed that a potential mechanism of action of the CNFs is the formation of a network surrounding and entrapping the bacteria. This effect is further potentiated by the oxygenation process. A CNF sample (concentration 0.6 wt %) that was oxygenated to a DO level of 46.4 mg/L demonstrated a strong antibacterial effect against S. aureus in vivo using a mouse model of surgical site infection. The oxygenated CNF dispersion reduced the bacterial survival by 71%, after 24 h treatment. The potent antibacterial effect indicates that oxygenated nanocellulose is a promising material for antibacterial wound dressings. © 2021 The Authors.
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| 45048. |
- Knutsen Rydberg, Ellen, 1969, et al.
(författare)
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Hypoxia increases LDL oxidation and expression of 15-lipoxygenase-2 in human macrophages
- 2004
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Ingår i: Arterioscler Thromb Vasc Biol. ; 24:11, s. 2040-2045
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Macrophage-mediated oxidation of low-density lipoprotein (LDL) by enzymes, such as the lipoxygenases, is considered of major importance for the formation of oxidized LDL during atherogenesis. Macrophages have been identified in hypoxic areas in atherosclerotic plaques. METHODS AND RESULTS: To investigate the role of hypoxia in macrophage-mediated LDL oxidation, we incubated human monocyte-derived macrophages with LDL under normoxic (21% O2) or hypoxic (0% O2) conditions. The results showed that hypoxic macrophages oxidized LDL to a significantly higher extent than normoxic cells. Interestingly, the mRNA and protein expression of 15-lipoxygenase-2 (15-LOX-2) as well as the activity of this enzyme are elevated in macrophages incubated at hypoxia. Both the unspliced 15-LOX-2 and the spliced variant 15-LOX-2sv-a are found in macrophages. In addition, 15-LOX-2 was identified in carotid plaques in some macrophage-rich areas but was only expressed at low levels in nondiseased arteries. CONCLUSIONS: In summary, these observations show for the first time that 15-LOX-2 is expressed in hypoxic macrophages and in atherosclerotic plaques and suggest that 15-LOX-2 may be one of the factors involved in macrophage-mediated LDL oxidation at hypoxia.
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| 45049. |
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| 45050. |
- Knutson, Tomas, et al.
(författare)
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Intraurethral prostate injections with mepivacaine epinephrine: effects on patient comfort, treatment time and energy consumption during high-energy transurethral microwave thermotherapy.
- 2009
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Ingår i: Scandinavian journal of urology and nephrology. - : Informa UK Limited. - 1651-2065 .- 0036-5599. ; 43:4, s. 300-6
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To investigate the effects of intraprostatic mepivacaine epinephrine injections administered by the Schelin catheter during high-energy transurethral microwave thermotherapy (TUMT) using the CoreTherm Prostalund Feedback Treatment (PLFT) system. MATERIAL AND METHODS: The study included 85 men with lower urinary tract symptoms due to benign prostatic enlargement. One group had intraprostatic injections with mepivacaine epinephrine by the new Schelin catheter, while patients in the other group were treated without intraprostatic injections. All men were treated by TUMT using the PLFT system. Before treatment, transrectal ultrasound (TRUS) volume was measured. During the procedure, treatment time, energy consumption, cell-kill parameter and maximal prostate temperature were recorded. Patients who needed perioperative intravenous analgesics and the rate of perioperative and postoperative complications were registered. RESULTS: The patients who had intraprostatic and periprostatic injections with mepivacaine epinephrine had shorter effective treatment time and reduced energy consumption. There was also a difference between the two groups in that 70% of patients without intraprostatic injections and only 11% of injected patients needed intravenous analgesics. No differences were found in TRUS volume, estimated cell-kill, maximal prostate temperature or complication rates. CONCLUSIONS: Intraprostatic injections with mepivacaine epinephrine distributed by the Schelin catheter reduce the number of patients needing intravenous analgesics during PLFT, as well as the treatment time and energy consumption during treatment. Besides improved patient comfort, intraprostatic and periprostatic injections condense the treatment time without side-effects, making PLFT less cumbersome for most patients.
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