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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Clancy, Neil T., et al.
(författare)
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Analysis of skin recovery from mechanical indentation using diffuse lighting and digital imaging. in Diffuse Optical Imaging of Tissue.
- 2007
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Ingår i: Proceedings of SPIE - Diffuse Optical Imaging of Tissue. - Bellingham, WA, United States : SPIE - International Society for Optical Engineering. - 9780819467737 ; , s. 66291G-1-66291G-10
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Konferensbidrag (refereegranskat)abstract
- Skin behaves as a viscoelastic material, having mechanical properties composed of elastic and fluid components. Upon indentation, the fibres are stretched and fluid displaced from the compressed region. The rate of recovery from this imprint is therefore dependent on the hydration and elasticity of the skin. A reliable measurement could be applied to the assessment of clinical conditions such as oedema, rare genetic disorders such as cutis laxa and the evaluation of the 'effective age' of skin in vivo . This paper describes a new approach to the non-invasive indentation technique and a novel method of analysis. A method is proposed that tracks the skin's recovery optically from an initial strain made using a mechanical indentor, diffuse side-lighting and a CCD video-capture device. Using the blue colour plane of the image it is possible to examine the surface topography only, and track the decay of the imprint over time. Two algorithms are discussed for the extraction of information on the skin's displacement and are analysed in terms of reliability and reproducibility.
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| 3. |
- Droog Tesselaar, Erik, et al.
(författare)
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A protocol for iontophoresis of acetylcholine and sodium nitroprusside that minimises nonspecific vasodilatory effects
- 2004
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Ingår i: Microvascular research. - : Elsevier BV. - 0026-2862. ; 67:2, s. 197-202
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Tidskriftsartikel (refereegranskat)abstract
- Iontophoresis of vasoactive substances is a promising tool for studying pharmacological aspects of the (patho)physiology of the microvasculature. However, nonspecific microvascular responses are a common problem in most protocols used. We studied the effect of current density (mA/cm2), charge density (mC/cm2), drug concentration (mass %) and vehicle concentration (M) on the nonspecific vasodilatation during iontophoresis of sodium chloride, acetylcholine (ACh) and sodium nitroprusside (SNP). We found that nonspecific vasodilatation depended on current density and charge density in both anodal and cathodal iontophoresis. The responses to ACh and SNP were dependent on current density, charge density and drug concentration. We found that by limiting current density (<0.01 mA/cm2) and charge density (<7.8 mC/cm2) and with adjusted concentrations for drugs and vehicles, it is possible to prevent nonspecific effects during iontophoresis of ACh and SNP, while maximum drug effects (plateaus in the dose–response curves) are still obtained. These new findings are important for future iontophoresis studies in which vasoactive drugs are used to assess microvascular function because the presented approach has advantages compared to older techniques, which mainly have attempted to suppress or compensate for the nonspecific responses during iontophoresis by the use of local anaesthetics or the measurement of drug-minus-vehicle responses, both of which present well-known experimental shortcomings.
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| 4. |
- Litscher, G., et al.
(författare)
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Changed skin blood perfusion in the fingertip following acupuncture needle introduction as evaluated by Laser Doppler Perfusion Imaging
- 2002
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Ingår i: Lasers in Medical Science. - : Springer Science and Business Media LLC. - 0268-8921 .- 1435-604X. ; 17:1, s. 19-25
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Tidskriftsartikel (refereegranskat)abstract
- Rapidly repeated imaging of the left middle fingertip skin blood perfusion was performed in 51 healthy volunteers (mean age ▒ SD: 25.3 ▒ 7.6 years) prior to, immediately after and in the early reperfusion phase following introduction of an acupuncture needle at the Neiguan point (Pe. 6) and at a placebo point respectively, using a Laser Doppler Perfusion Imager (LDPI). The average skin perfusion of the fingertip was calculated for each image and used as an indicator of the microvascular response to the acupuncture needle introduction. The results of this randomised, placebo-controlled, cross-over study showed significant differences (p = 0.001) in the immediate skin blood perfusion response when needling is performed in an acupuncture point (Neiguan) and a placebo point, with a more pronounced reduction in skin blood perfusion when needling the acupuncture point. In the early reperfusion phase, however, a substantial increase in skin perfusion was observed that amounted to about 18% of the level prior to needle introduction, irrespective of the site of needle application. In a single individual it was demonstrated that the vasodilatation following needling in the acupuncture point persisted for a more extended time period. These results suggest that the LDPI technology may be useful in visualising and quantifying the peripheral vascular effects of acupuncture on the microcirculation.
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| 5. |
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| 6. |
- Nilsson, IngMarie, et al.
(författare)
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Photocross-linking of nascent chains to the STT3 subunit of the oligosaccharyltransferase complex
- 2003
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Ingår i: Journal of Cell Biology. - : Rockefeller University Press. - 0021-9525 .- 1540-8140. ; 161:4, s. 715-725
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Tidskriftsartikel (refereegranskat)abstract
- In eukaryotic cells, polypeptides are N glycosylated after passing through the membrane of the ER into the ER lumen. This modification is effected cotranslationally by the multimeric oligosaccharyltransferase (OST) enzyme. Here, we report the first cross-linking of an OST subunit to a nascent chain that is undergoing translocation through, or integration into, the ER membrane. A photoreactive probe was incorporated into a nascent chain using a modified Lys-tRNA and was positioned in a cryptic glycosylation site (-Q-K-T- instead of -N-K-T-) in the nascent chain. When translocation intermediates with nascent chains of increasing length were irradiated, nascent chain photocross-linking to translocon components, Sec61alpha and TRAM, was replaced by efficient photocross-linking solely to a protein identified by immunoprecipitation as the STT3 subunit of the OST No cross-linking was observed in the absence of a cryptic sequence or in the presence of a competitive peptide substrate of the OST. As no significant nascent chain photocross-linking to other OST subunits was detected in these fully assembled translocation and integration intermediates, our results strongly indicate that the nascent chain portion of the OST active site is located in STT3.
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| 7. |
- O'Doherty, Jim, et al.
(författare)
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Tissue viability imaging (TiVi) in the assessment of divergent beam UV-B provocation
- 2011
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Ingår i: Archives of Dermatological Research. - : Springer. - 0340-3696 .- 1432-069X. ; 303:2, s. 79-87
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Tidskriftsartikel (refereegranskat)abstract
- In routine clinical phototesting and in basic research, naked eye dermatological assessment is the "gold standard" for determining the patient's minimal erythemal dose (MED). In UV-B testing with a divergent, radially attenuating beam of characterised dosimetry, laser Doppler perfusion imaging has been previously used to give quantitative description of reactivity to doses above the MED in addition to a "single-dose" objective determination of the MED itself. In the present paper, the recently developed tissue viability imaging (TiVi) technology is presented for the first time as a reliable, easily applicable, high-resolution alternative to LDPI in the divergent beam testing concept. Data obtained after provocation with a range of doses was analysed in order to determine the reaction diameter, which can be related to the MED using field dosimetry. The dose-response features of exposure above the MED and the relationship between naked eye readings and the diameter were determined from the image data. TiVi data were obtained faster than LDPI data and at a higher spatial resolution of 100 μm instead of 1 mm. A tool was developed to centre over the erythema area of the acquired image. Response data could be plotted continuously against dose. Thresholding of processed images compared to naked eye "gold standard" readings showed that the normal skin value +4 standard deviations produced a good fit between both methods. A linear fitting method for the dose-response data provided a further method of determination of the reaction diameter (MED). Erythemal "volume under the surface (VUS)" for the reaction provided a new concept for visualising information. TiVi offers advantages over LDPI in the acquisition and analysis of data collected during divergent beam testing. An increased amount of data compared to traditional phototesting is easily and more objectively obtained which increases applicability in the clinical and research environment.
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| 8. |
- Toll John, Rani, et al.
(författare)
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Reflectance spectroscopy : to shed new light on the capillary refill test
- 2018
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Ingår i: Journal of Biophotonics. - : Wiley-VCH Verlagsgesellschaft. - 1864-063X .- 1864-0648. ; 11:1
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Tidskriftsartikel (refereegranskat)abstract
- To use Bioengineering methodology is used to achieve, at five anatomical sites, a detailed, quantitative assessment of the return of blood content to the blanched area, during the Capillary Refill (CR) test. An observational, non-randomized, experimental study on 23 healthy subjects (14 females) was performed in our climate controlled skin physiology laboratory. Our main outcome measures were based on the chronological assessment and quantification of red blood cell concentration (RBC) after the release of blanching pressure in the CR test, using Tissue Viability Imaging (TiVi), a digital photographic technique based on polarisation spectroscopy. TiVi enabled collection of detailed data on skin RBC concentration during the CR test. The results were shown as curves with skin blood concentration (TiVi-value) on the y-axis and the time on the x-axis. Quantitative CR responses showed site and temperature variability. We also suggest possible objective endpoint values from the capillary refill curve. Detailed data on skin RBC concentration during the CR test is easily obtained and allows objective determination of end points not possible to achieve by naked eye assessment. These findings have the potential to place the utility of the CR test in a clinical setting in a new light. Picture: Regular photograph and TiVi Image showing CR test and corresponding graph for the CR response. [GRAPHICS] .
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| 9. |
- Warvsten, Anna, et al.
(författare)
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Islet autoantibodies present in association with Ljungan virus infection in bank voles (Myodes glareolus) in northern Sweden
- 2017
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Ingår i: Journal of Medical Virology. - : Wiley. - 1096-9071 .- 0146-6615. ; 89:1, s. 24-31
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Tidskriftsartikel (refereegranskat)abstract
- Bank voles are known reservoirs for Puumala hantavirus and probably also for Ljungan virus (LV), a suggested candidate parechovirus in type 1 diabetes etiology and pathogenesis. The aim of this study was to determine whether wild bank voles had been exposed to LV and if exposure associated to autoantibodies against insulin (IAA), glutamic acid decarboxylase 65 (GADA), or islet autoantigen-2 (IA-2A). Serum samples from bank voles (Myodes glareolus) captured in early summer or early winter of 1997 and 1998, respectively, were analyzed in radio binding assays for antibodies against Ljungan virus (LVA) and Puumala virus (PUUVA) as well as for IAA, GADA, and IA-2A. LVA was found in 25% (189/752), IAA in 2.5% (18/723), GADA in 2.6% (15/615), and IA-2A in 2.5% (11/461) of available bank vole samples. LVA correlated with both IAA (P = 0.007) and GADA (P < 0.001), but not with IA-2A (P = 0.999). There were no correlations with PUUVA, detected in 17% of the bank voles. Compared to LVA negative bank voles, LVA positive animals had higher levels of both IAA (P = 0.002) and GADA (P < 0.001), but not of IA-2A (P = 0.205). Levels of LVA as well as IAA and GADA were higher in samples from bank voles captured in early summer. In conclusion, LVA was detected in bank voles and correlated with both IAA and GADA but not with IA-2A. These observations suggest that exposure to LV may be associated with islet autoimmunity. It remains to be determined if islet autoantibody positive bank voles may develop diabetes in the wild. J. Med. Virol. 89:24-31, 2017. © 2016 Wiley Periodicals, Inc.
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| 10. |
- Wennberg, Maria, 1974-, et al.
(författare)
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Dietary transition
- 2021. - 1
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Ingår i: Amap assesment 2021. - Tromsö : AMAP. - 9788279712008 ; , s. 13-46
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Key findings:Most Arctic populations have experienced a transition towards more imported foods. The dietary transition has had adverse impacts on health in some populations, such as an increase in obesity or impaired dental status. Intakes of vitamin D and iodine have decreased due to lower fish and/or milk consumption. These nutrients should be monitored in Arctic populations. Positive health impacts of the dietary transition include significantly reduced levels of contaminants in the blood of pregnant women. Whether dietary transition is negative or positive for health depends on the composition of the new diet, as well as the extent to which the traditional diet is maintained. Communication about dietary risks and benefits is vital. Food insecurity is a growing concern in some Arctic populations and collaboration between countries should be established to address this. There are gaps in the research field of dietary studies within Arctic Indigenous populations. More studies are needed, especially within the many Arctic populations in Russia
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