| 1. |
- Dyrager, Christine, 1975, et al.
(författare)
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2,6,8-Trisubstituted 3-hydroxychromone derivatives as fluorophores for live-cell imaging.
- 2009
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Ingår i: Chemistry (Weinheim an der Bergstrasse, Germany). - : Wiley. - 1521-3765 .- 0947-6539. ; 15:37, s. 9417-23
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Tidskriftsartikel (refereegranskat)abstract
- We present the synthesis and photophysical characterisation of a series of structurally diverse, fluorescent 2,6,8-trisubstituted 3-hydroxychromone derivatives with high fluorescence quantum yields and molar extinction coefficients. Two of these derivatives (9 and 10 a) have been studied as fluorophores for cellular imaging in HeLa cells and show excellent permeability and promising fluorescence properties in a cellular environment. In addition, we have demonstrated by photophysical characterisation of 3-isobutyroxychromone derivatives that esterification of the 3-hydroxyl group results in acceptable and useful fluorescence properties.
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| 2. |
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| 3. |
- Babazadeh, Roja, et al.
(författare)
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Osmostress-induced cell volume loss delays yeast hog1 signaling by limiting diffusion processes and by hog1-specific effects.
- 2013
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 8:11
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Tidskriftsartikel (refereegranskat)abstract
- Signal transmission progresses via a series of transient protein-protein interactions and protein movements, which require diffusion within a cell packed with different molecules. Yeast Hog1, the effector protein kinase of the High Osmolarity Glycerol pathway, translocates transiently from the cytosol to the nucleus during adaptation to high external osmolarity. We followed the dynamics of osmostress-induced cell volume loss and Hog1 nuclear accumulation upon exposure of cells to different NaCl concentrations. While Hog1 nuclear accumulation peaked within five minutes following mild osmotic shock it was delayed up to six-fold under severe stress. The timing of Hog1 nuclear accumulation correlated with the degree of cell volume loss and the cells capacity to recover. Also the nuclear translocation of Msn2, the transcription factor of the general stress response pathway, is delayed upon severe osmotic stress suggesting a general phenomenon. We show by direct measurements that the general diffusion rate of Hog1 in the cytoplasm as well as its rate of nuclear transport are dramatically reduced following severe volume reduction. However, neither Hog1 phosphorylation nor Msn2 nuclear translocation were as much delayed as Hog1 nuclear translocation. Our data provide direct evidence that signaling slows down during cell volume compression, probably as a consequence of molecular crowding. Hence one purpose of osmotic adaptation is to restore optimal diffusion rates for biochemical and cell biological processes. In addition, there may be mechanisms slowing down especially Hog1 nuclear translocation under severe stress in order to prioritize Hog1 cytosolic targets.
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| 4. |
- Bender, Johanna, 1975, et al.
(författare)
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Lipid cubic phases in topical drug delivery: Visualization of skin distribution using two-photon microscopy
- 2008
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Ingår i: Journal of Controlled Release. - : Elsevier BV. - 0168-3659 .- 1873-4995. ; 129:3, s. 163-169
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Tidskriftsartikel (refereegranskat)abstract
- The distribution of sulphorhodamine B (SRB), a fluorescent hydrophilic model drug, was investigated in human skin after passive diffusion using four different topical delivery systems. The delivery vehicles applied were two bicontinuous lipid cubic systems, a commercial ointment and water. The lipid cubic systems consisted of either monoolein (MO) or phytantriol (PT) and water. The formulations were applied on full-thickness human skin during 24 h. Thereafter the samples were investigated using two-photon microscopy (TPM). The TPM system consisted of an inverted microscope with a 40× water-immersion objective, laser scan-box, and a pulsed femtosecond titanium:sapphire laser operating at 780 nm. The fluorescence was detected using a 560 nm long-pass filter. Sequential optical sectioning was performed, resulting in images obtained at different tissue depths. TPM revealed that SRB mainly penetrates the skin via the intercellular lipid matrix. Samples exposed to the cubic phases showed a higher accumulation of SRB in micro-fissures, from which a fluorescent network of threadlike structures spread laterally in the tissue. These structures were also detected in some of the ointment samples, but not as frequent. The penetration of SRB into the stratum granulosum was deduced from the fluorescence of SRB present inside polygonal keratinocytes with cell nuclei. Higher SRB fluorescence was obtained in the outermost layer of the epidermis using the bicontinuous cubic phases, compared to when using the reference formulations. Thus, our results suggest that the dominating delivery route using the cubic phases is via micro-fissures caused by microscopic clustering of the keratinocytes in the skin. From these micro--fissures hydrophilic compounds, here modeled by SRB, can diffuse into the surrounding intercellular lipid matrix acting like a source for sustained release.
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| 5. |
- Bendrioua, Loubna, et al.
(författare)
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Yeast AMP-activated protein kinase monitors glucose concentration changes and absolute glucose levels
- 2014
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 289:18, s. 12863-12875
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Tidskriftsartikel (refereegranskat)abstract
- Background: Little is known about the signaling dynamics of AMP-activated protein kinase. Results: We define the dynamics of yeast AMPK signaling under different glucose concentrations. Conclusion: The Snf1-Mig1 signaling system monitors glucose concentration changes and absolute glucose levels to adjust the metabolism to a wide range of conditions. Significance: This description of AMPK signaling dynamics will stimulate studies defining the integration of signaling and metabolism. © 2014 by The American Society for Biochemistry and Molecular Biology, Inc.
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| 6. |
- Borg, Mikael, et al.
(författare)
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Experimental and theoretical surface core-level shifts of aluminum (100) and (111)
- 2004
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Ingår i: Physical Review B. - 1550-235X. ; 69
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Tidskriftsartikel (refereegranskat)abstract
- The surface core-level shifts of Al(111) and Al(100) have been measured using high-resolution core-level photoemission spectroscopy and calculated using density functional theory (DFT). For Al(100), the 2p core-level shift of the first (second) layer was determined to be –75 meV (+20 meV) from experiment and –71 meV (+20 meV) from the DFT calculations. For Al(111), the corresponding values are –27 meV (0 meV) from experiment and –14 meV (–) from the DFT calculations. Core-level splittings caused by the low-symmetry crystal fields at the (111) and (100) surfaces have also been studied. These splittings turn out to be much smaller than previously reported provided proper care is taken of the influence of the core hole screening and of core–valence exchange beyond the DFT level. Finally, the experimental Al 2p line shape was found to contain structure caused by a sharp no-phonon line and a broad and weak phonon replica.
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| 7. |
- Chabok, Abbas, et al.
(författare)
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Prevalence of fecal carriage of antibiotic-resistant bacteria in patients with acute surgical abdominal infections
- 2010
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Ingår i: SCANDINAVIAN JOURNAL OF GASTROENTEROLOGY. - : Informa Healthcare. - 0036-5521 .- 1502-7708. ; 45:10, s. 1203-1210
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Tidskriftsartikel (refereegranskat)abstract
- Objective. Antibiotic resistance is increasing worldwide. The aims of the current study were to determine the fecal carriage of antibiotic-resistant bacteria and antibiotic treatment in surgical patients admitted to hospital due to acute intra-abdominal infections. Materials and methods. Eight Swedish surgical units participated in this prospective multicenter investigation. Rectal swabs were obtained on admission to hospital. Cultures were performed on chromogenic agar and antibiotic susceptibility testing was performed using the disk diffusion method. Extended-spectrum beta-lactamase (ESBL)phenotype was confirmed by Etest. Results. Rectal samples were obtained and analyzed from 208 patients with intra-abdominal surgical infections. Surgery was performed in 134 patients (65%). Cephalosporins were the most frequently used empirical antibiotic therapy. The highest rates of resistance among Enterobacteriaceae were detected for ampicillin (54%), tetracycline (26%), cefuroxime (26%) and trimethoprim-sulfamethoxazole (20%). The prevalence of decreased susceptibility (I + R) for the other antibiotics tested was for ciprofloxacin 20%, piperacillin-tazobactam 17%, cefotaxime 14%, ertapenem 12%, gentamicin 3% and imipenem 0%. ESBL-producing Enterobacteriaceae were found in samples from 10 patients (5%). Three patients had five E. coli isolates producing AmpC enzymes. Conclusions. This study shows a high rate of resistance among Enterobacteriaceae against antibiotics which are commonly used in Sweden and should have implications for the future choice of antibiotics for surgical patients.
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| 8. |
- Collin, Åsa, et al.
(författare)
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The effect of local gentamicin-collagen on perineal wound complications and cancer recurrence after abdominoperineal resection : a multicentre randomised controlled trial
- 2013
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Ingår i: Colorectal Disease. - : Wiley. - 1462-8910 .- 1463-1318. ; 15:3, s. 341-346
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Perineal wound sepsis is a common problem after abdominoperineal resection of the rectum (APR), with an reported incidence of 10-15% in previously non-radiated patients, 20-30% in patients given preoperative radiation, and 50% among patients submitted to preoperative radiation combined with chemotherapy. The local application of gentamicin-collagen was evaluated to determine whether its use in the perineal wound reduced the risk complications and had an effect on cancer recurrence.Method: In this prospective multicentre (7 hospitals) randomised controlled trial, 102 patients undergoing APR due to cancer or benign disease were randomised into two groups including surgery with gentamicin-collagen (GS+ n=52), or surgery without gentamicin-collagen (GS- n=50), Patients were followed at 7, 30 and 90 days and at one and five years.Results: There were no statistically significant differences between the two groups regarding perineal wound complications, infectious or non-infectious or cancer recurrence.Conclusion: There was no statistically significant effect on perineal wound complications or cancer recurrence following the local administration of gentamicin-collagen during APR.
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| 9. |
- Ericson, Marica B, 1974, et al.
(författare)
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Two-photon laser-scanning fluorescence microscopy applied for studies of human skin
- 2008
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Ingår i: Journal of Biophotonics. - : Wiley. - 1864-0648 .- 1864-063X. ; 1:4, s. 320-330
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Tidskriftsartikel (refereegranskat)abstract
- Two-photon laser scanning fluorescence microscopy (TPM) has been shown to be advantageous for imaging optically turbid media such as human skin. The ability of performing three-dimensional imaging without presectioning of the samples makes the technique not only suitable for noninvasive diagnostics but also for studies of topical delivery of xenobiotics. Here, TPM is used as a method to visualize both autofluorescent and exogenous fluorophores in skin. Samples exposed to sulforhodamine B have been scanned from two directions to investigate attenuation effects. It is shown that optical effects play a major role. Thus, TPM is excellent for visualizing the localization and distribution of fluorophores in human skin, although quantification might be difficult. Furthermore, an image-analysis algorithm has been implemented to facilitate interpretation of TPM images of autofluorescent features of nonmelanoma skin cancer obtained ex vivo. The algorithm was designed to detect cell nuclei and currently has a sensitivity and specificity of 82% and 78% to single cell nuclei. However, in order to detect multinucleated cells, the algorithm needs further development. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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| 10. |
- Ericson, Marica B, 1974, et al.
(författare)
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Two-photon microscopy of non-melanoma skin cancer: initial experience and diagnostic criteria ex vivo
- 2007
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Ingår i: Proc. SPIE. - : SPIE. ; 6630
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Konferensbidrag (refereegranskat)abstract
- Multiphoton microscopy is an interesting optical technique, which allows for non-invasive imaging of highly light scattering media such as human skin. Recent reports have showed the potential of applying this technique for 3D visualisation of cell structures of biological tissue without previous sectioning of the tissue samples. In this study, we have applied two-photon microscopy on excised lesions of human non-melanoma skin cancer ex vivo in order to find diagnostic criteria using this technique. The skin samples have been investigated by a multiphoton microscopy system based on a fs-pulsed Ti:sapphire laser connected to a confocal microscope. The autofluorescence of the skin was detected using excitation at 780 nm. The cell nuclei distribution turned out to be one important parameter, which can be used for discriminating between tumour and normal tissue. We are now developing a technique for automatic detection and characterisation of tissue, based on an image analysis algorithm. The detection of cell nuclei has been found crucial for this purpose. The goal is to develop a fast characterisation algorithm that can be used on line in connection to in vivo investigations. This would allow for a true non-invasive biopsy technique in the future.
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