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Zamorano AM, Zatorre RJ, Vuust P, Friberg A, Birbaumer N, Kleber B. Singing training predicts increased insula connectivity with speech and respiratory sensorimotor areas at rest. Brain Res 2023:148418. [PMID: 37217111 DOI: 10.1016/j.brainres.2023.148418] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Revised: 03/28/2023] [Accepted: 05/17/2023] [Indexed: 05/24/2023]
Abstract
The insula contributes to the detection of salient events during goal-directed behavior and participates in the coordination of motor, multisensory, and cognitive systems. Recent task-fMRI studies with trained singers suggest that singing experience can enhance the access to these resources. However, the long-term effects of vocal training on insula-based networks are still unknown. In this study, we employed resting-state fMRI to assess experience-dependent differences in insula co-activation patterns between conservatory-trained singers and non-singers. Results indicate enhanced bilateral anterior insula connectivity in singers relative to non-singers with constituents of the speech sensorimotor network. Specifically, with the cerebellum (lobule V-VI) and the superior parietal lobes. The reversed comparison showed no effects. The amount of accumulated singing training predicted enhanced bilateral insula co-activation with primary sensorimotor areas representing the diaphragm and the larynx/phonation area-crucial regions for cortico-motor control of complex vocalizations-as well as the bilateral thalamus and the left putamen. Together, these findings highlight the neuroplastic effect of expert singing training on insula-based networks, as evidenced by the association between enhanced insula co-activation profiles in singers and the brain's speech motor system components.
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Affiliation(s)
- A M Zamorano
- Center for Neuroplasticity and Pain (CNAP), Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - R J Zatorre
- McGill University-Montreal Neurological Institute, Neuropsychology and Cognitive Neuroscience, Montreal, Canada; International Laboratory for Brain, Music and Sound research (BRAMS), Montreal, Canada
| | - P Vuust
- Center for Music in the Brain, Department of Clinical Medicine, Aarhus University, & The Royal Academy of Music Aarhus/Aalborg, Denmark
| | - A Friberg
- Speech, Music and Hearing, KTH Royal Institute of Technology, Stockholm, Sweden
| | - N Birbaumer
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany
| | - B Kleber
- Institute for Medical Psychology and Behavioral Neurobiology, University of Tübingen, Germany; Center for Music in the Brain, Department of Clinical Medicine, Aarhus University, & The Royal Academy of Music Aarhus/Aalborg, Denmark.
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Harandi V, Moreira Soares Oliveira B, Friberg A, Gawlik K, Durbeej M. P.331Effects of N-acetyl-L-cysteine and vitamin E on congenital muscular dystrophy type 1A disease progression in mice. Neuromuscul Disord 2019. [DOI: 10.1016/j.nmd.2019.06.445] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Ansite J, Balamurugan AN, Barbaro B, Battle J, Brandhorst D, Cano J, Chen X, Deng S, Feddersen D, Friberg A, Gilmore T, Goldstein JS, Holbrook E, Khan A, Kin T, Lei J, Linetsky E, Liu C, Luo X, McElvaney K, Min Z, Moreno J, O'Gorman D, Papas KK, Putz G, Ricordi C, Szot G, Templeton T, Wang L, Wilhelm JJ, Willits J, Wilson T, Zhang X, Avila J, Begley B, Cano J, Carpentier S, Holbrook E, Hutchinson J, Larsen CP, Moreno J, Sears M, Turgeon NA, Webster D, Deng S, Lei J, Markmann JF, Bridges ND, Czarniecki CW, Goldstein JS, Putz G, Templeton T, Wilson T, Eggerman TL, Al-Saden P, Battle J, Chen X, Hecyk A, Kissler H, Luo X, Molitch M, Monson N, Stuart E, Wallia A, Wang L, Wang S, Zhang X, Bigam D, Campbell P, Dinyari P, Kin T, Kneteman N, Lyon J, Malcolm A, O'Gorman D, Onderka C, Owen R, Pawlick R, Richer B, Rosichuk S, Sarman D, Schroeder A, Senior PA, Shapiro AMJ, Toth L, Toth V, Zhai W, Johnson K, McElroy J, Posselt AM, Ramos M, Rojas T, Stock PG, Szot G, Barbaro B, Martellotto J, Oberholzer J, Qi M, Wang Y, Bayman L, Chaloner K, Clarke W, Dillon JS, Diltz C, Doelle GC, Ecklund D, Feddersen D, Foster E, Hunsicker LG, Jasperson C, Lafontant DE, McElvaney K, Neill-Hudson T, Nollen D, Qidwai J, Riss H, Schwieger T, Willits J, Yankey J, Alejandro R, Corrales AC, Faradji R, Froud T, Garcia AA, Herrada E, Ichii H, Inverardi L, Kenyon N, Khan A, Linetsky E, Montelongo J, Peixoto E, Peterson K, Ricordi C, Szust J, Wang X, Abdulla MH, Ansite J, Balamurugan AN, Bellin MD, Brandenburg M, Gilmore T, Harmon JV, Hering BJ, Kandaswamy R, Loganathan G, Mueller K, Papas KK, Pedersen J, Wilhelm JJ, Witson J, Dalton-Bakes C, Fu H, Kamoun M, Kearns J, Li Y, Liu C, Luning-Prak E, Luo Y, Markmann E, Min Z, Naji A, Palanjian M, Rickels M, Shlansky-Goldberg R, Vivek K, Ziaie AS, Fernandez L, Kaufman DB, Zitur L, Brandhorst D, Friberg A, Korsgren O. Purified Human Pancreatic Islets, CIT Culture Media with Lisofylline or Exenatide. CellR4 Repair Replace Regen Reprogram 2017; 5:e2377. [PMID: 30613755 PMCID: PMC6319648] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
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Etemadi L, Mohammed M, Thorbergsson PT, Ekstrand J, Friberg A, Granmo M, Pettersson LME, Schouenborg J. Embedded Ultrathin Cluster Electrodes for Long-Term Recordings in Deep Brain Centers. PLoS One 2016; 11:e0155109. [PMID: 27159159 PMCID: PMC4861347 DOI: 10.1371/journal.pone.0155109] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Accepted: 04/25/2016] [Indexed: 01/03/2023] Open
Abstract
Neural interfaces which allow long-term recordings in deep brain structures in awake freely moving animals have the potential of becoming highly valuable tools in neuroscience. However, the recording quality usually deteriorates over time, probably at least partly due to tissue reactions caused by injuries during implantation, and subsequently micro-forces due to a lack of mechanical compliance between the tissue and neural interface. To address this challenge, we developed a gelatin embedded neural interface comprising highly flexible electrodes and evaluated its long term recording properties. Bundles of ultrathin parylene C coated platinum electrodes (N = 29) were embedded in a hard gelatin based matrix shaped like a needle, and coated with Kollicoat™ to retard dissolution of gelatin during the implantation. The implantation parameters were established in an in vitro model of the brain (0.5% agarose). Following a craniotomy in the anesthetized rat, the gelatin embedded electrodes were stereotactically inserted to a pre-target position, and after gelatin dissolution the electrodes were further advanced and spread out in the area of the subthalamic nucleus (STN). The performance of the implanted electrodes was evaluated under anesthesia, during 8 weeks. Apart from an increase in the median-noise level during the first 4 weeks, the electrode impedance and signal-to-noise ratio of single-units remained stable throughout the experiment. Histological postmortem analysis confirmed implantation in the area of STN in most animals. In conclusion, by combining novel biocompatible implantation techniques and ultra-flexible electrodes, long-term neuronal recordings from deep brain structures with no significant deterioration of electrode function were achieved.
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Affiliation(s)
- Leila Etemadi
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Mohsin Mohammed
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail: (MM); (JS); (LP)
| | - Palmi Thor Thorbergsson
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Joakim Ekstrand
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Annika Friberg
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Marcus Granmo
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
| | - Lina M. E. Pettersson
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail: (MM); (JS); (LP)
| | - Jens Schouenborg
- Neuronano Research Center, Department of Experimental Medical Science, Lund University, Lund, Sweden
- * E-mail: (MM); (JS); (LP)
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Fridén-Saxin M, Seifert T, Malo M, da Silva Andersson K, Pemberton N, Dyrager C, Friberg A, Dahlén K, Wallén EA, Grøtli M, Luthman K. Chroman-4-one and chromone based somatostatin β-turn mimetics. Eur J Med Chem 2016; 114:59-64. [DOI: 10.1016/j.ejmech.2016.02.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2016] [Revised: 02/17/2016] [Accepted: 02/18/2016] [Indexed: 11/28/2022]
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Holmkvist AD, Friberg A, Nilsson UJ, Schouenborg J. Hydrophobic ion pairing of a minocycline/Ca 2+ /AOT complex for preparation of drug-loaded PLGA nanoparticles with improved sustained release. Int J Pharm 2016; 499:351-357. [DOI: 10.1016/j.ijpharm.2016.01.011] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 12/28/2015] [Accepted: 01/05/2016] [Indexed: 01/14/2023]
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Agorelius J, Tsanakalis F, Friberg A, Thorbergsson PT, Pettersson LME, Schouenborg J. An array of highly flexible electrodes with a tailored configuration locked by gelatin during implantation-initial evaluation in cortex cerebri of awake rats. Front Neurosci 2015; 9:331. [PMID: 26441505 PMCID: PMC4585103 DOI: 10.3389/fnins.2015.00331] [Citation(s) in RCA: 49] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 09/04/2015] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND A major challenge in the field of neural interfaces is to overcome the problem of poor stability of neuronal recordings, which impedes long-term studies of individual neurons in the brain. Conceivably, unstable recordings reflect relative movements between electrode and tissue. To address this challenge, we have developed a new ultra-flexible electrode array and evaluated its performance in awake non-restrained animals. METHODS An array of eight separated gold leads (4 × 10 μm), individually flexible in 3D, were cut from a gold sheet using laser milling and insulated with Parylene C. To provide structural support during implantation into rat cortex, the electrode array was embedded in a hard gelatin based material, which dissolves after implantation. Recordings were made during 3 weeks. At termination, the animals were perfused with fixative and frozen to prevent dislocation of the implanted electrodes. A thick slice of brain tissue, with the electrode array still in situ, was made transparent using methyl salicylate to evaluate the conformation of the implanted electrode array. RESULTS Median noise levels and signal/noise remained relatively stable during the 3 week observation period; 4.3-5.9 μV and 2.8-4.2, respectively. The spike amplitudes were often quite stable within recording sessions and for 15% of recordings where single-units were identified, the highest-SNR unit had an amplitude higher than 150 μV. In addition, high correlations (>0.96) between unit waveforms recorded at different time points were obtained for 58% of the electrode sites. The structure of the electrode array was well preserved 3 weeks after implantation. CONCLUSIONS A new implantable multichannel neural interface, comprising electrodes individually flexible in 3D that retain its architecture and functionality after implantation has been developed. Since the new neural interface design is adaptable, it offers a versatile tool to explore the function of various brain structures.
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Affiliation(s)
- Johan Agorelius
- Department of Experimental Medical Science, Neuronano Research Centre, Lund UniversityLund, Sweden
- The Nanometer Structure Consortium, Lund UniversityLund, Sweden
| | - Fotios Tsanakalis
- Department of Experimental Medical Science, Neuronano Research Centre, Lund UniversityLund, Sweden
| | - Annika Friberg
- Department of Experimental Medical Science, Neuronano Research Centre, Lund UniversityLund, Sweden
| | - Palmi T. Thorbergsson
- Department of Experimental Medical Science, Neuronano Research Centre, Lund UniversityLund, Sweden
| | - Lina M. E. Pettersson
- Department of Experimental Medical Science, Neuronano Research Centre, Lund UniversityLund, Sweden
| | - Jens Schouenborg
- Department of Experimental Medical Science, Neuronano Research Centre, Lund UniversityLund, Sweden
- The Nanometer Structure Consortium, Lund UniversityLund, Sweden
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Tomsen D, Armandi HB, Friberg A, McNulty H, Skovsted LB. CPC-075 Interdisciplinary Taskforce Brings Down Price of HIV Drugs! Eur J Hosp Pharm 2013. [DOI: 10.1136/ejhpharm-2013-000276.532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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Istók E, Friberg A, Huotilainen M, Tervaniemi M. Expressive timing facilitates the processing of phrase boundaries in music: Evidence from the event-related potential. Int J Psychophysiol 2012. [DOI: 10.1016/j.ijpsycho.2012.07.108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Collinet B, Friberg A, Brooks MA, van den Elzen T, Henriot V, Dziembowski A, Graille M, Durand D, Leulliot N, Saint André C, Lazar N, Sattler M, Séraphin B, van Tilbeurgh H. Strategies for the structural analysis of multi-protein complexes: lessons from the 3D-Repertoire project. J Struct Biol 2011; 175:147-58. [PMID: 21463689 DOI: 10.1016/j.jsb.2011.03.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2011] [Revised: 03/18/2011] [Accepted: 03/19/2011] [Indexed: 11/25/2022]
Abstract
Structural studies of multi-protein complexes, whether by X-ray diffraction, scattering, NMR spectroscopy or electron microscopy, require stringent quality control of the component samples. The inability to produce 'keystone' subunits in a soluble and correctly folded form is a serious impediment to the reconstitution of the complexes. Co-expression of the components offers a valuable alternative to the expression of single proteins as a route to obtain sufficient amounts of the sample of interest. Even in cases where milligram-scale quantities of purified complex of interest become available, there is still no guarantee that good quality crystals can be obtained. At this step, protein engineering of one or more components of the complex is frequently required to improve solubility, yield or the ability to crystallize the sample. Subsequent characterization of these constructs may be performed by solution techniques such as Small Angle X-ray Scattering and Nuclear Magnetic Resonance to identify 'well behaved' complexes. Herein, we recount our experiences gained at protein production and complex assembly during the European 3D Repertoire project (3DR). The goal of this consortium was to obtain structural information on multi-protein complexes from yeast by combining crystallography, electron microscopy, NMR and in silico modeling methods. We present here representative set case studies of complexes that were produced and analyzed within the 3DR project. Our experience provides useful insight into strategies that are more generally applicable for structural analysis of protein complexes.
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Affiliation(s)
- B Collinet
- IBBMC-CNRS UMR8619, IFR 115, Bât. 430, Université Paris-Sud, 91405 Orsay, France
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Dyrager C, Wickström M, Fridén-Saxin M, Friberg A, Dahlén K, Wallén EA, Gullbo J, Grøtli M, Luthman K. Inhibitors and promoters of tubulin polymerization: Synthesis and biological evaluation of chalcones and related dienones as potential anticancer agents. Bioorg Med Chem 2011; 19:2659-65. [DOI: 10.1016/j.bmc.2011.03.005] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2010] [Revised: 02/27/2011] [Accepted: 03/03/2011] [Indexed: 11/16/2022]
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Brandhorst H, Friberg A, Nilsson B, Andersson HH, Felldin M, Foss A, Salmela K, Tibell A, Tufveson G, Korsgren O, Brandhorst D. Large-scale comparison of Liberase HI and collagenase NB1 utilized for human islet isolation. Cell Transplant 2009; 19:3-8. [PMID: 19818208 DOI: 10.3727/096368909x477507] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
For more than a decade Liberase HI was commonly used as the standard enzyme blend for clinical human islet isolation until enforced replacement by collagenase NB1 (NB1). This change resulted initially in a reduction in islet isolation outcome and transplant activities worldwide. This retrospective study was initiated to compare the efficiency of NB1 premium grade with Liberase in 197 human islet isolations. All pancreata were processed between January 2006 and June 2008 utilizing the same procedures for isolation and quality assessment except the administration of preselected lots of either Liberase (n = 101) or NB1 (n = 96). Utilizing Liberase, significantly more digested tissue and purified islet yield was produced compared to NB1. In contrast, the use of NB1 was associated with significantly higher purity and glucose stimulation index during dynamic perifusion. The expression of proinflammatory markers was almost identical except tissue factor expression, which was higher after utilization of Liberase. No difference was found in the percentage of pancreata fulfilling the criteria for clinical islet transplantation. The results suggest that Liberase is more efficient for pancreas dissociation than collagenase NB1 but seems to be more harmful to exocrine cells and islet tissue.
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Affiliation(s)
- H Brandhorst
- Department of Oncology, Radiology & Clinical Immunology, Uppsala University, Uppsala, Sweden
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Dyrager C, Friberg A, Dahlén K, Fridén-Saxin M, Börjesson K, Wilhelmsson LM, Smedh M, Grøtli M, Luthman K. 2,6,8-Trisubstituted 3-Hydroxychromone Derivatives as Fluorophores for Live-Cell Imaging. Chemistry 2009; 15:9417-23. [PMID: 19670192 DOI: 10.1002/chem.200900279] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Christine Dyrager
- Department of Chemistry-Medicinal Chemistry, University of Gothenburg, 412 96 Göteborg, Sweden
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Fridén-Saxin M, Pemberton N, Andersson KDS, Dyrager C, Friberg A, Grøtli M, Luthman K. Synthesis of 2-alkyl-substituted chromone derivatives using microwave irradiation. J Org Chem 2009; 74:2755-9. [PMID: 19323574 DOI: 10.1021/jo802783z] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A base-promoted condensation between 2-hydroxyacetophenones and aliphatic aldehydes has been studied. The reaction has been optimized to afford 2-alkyl-substituted 4-chromanones in an efficient manner using microwave heating. Performing the reaction using diisopropylamine in EtOH at 170 degrees C for 1 h gave moderate to high yields (43-88%). The 4-chromanones could be further converted into highly functionalized 2,3,6,8-tetrasubstituted chromones in which a 3-substituent (acetate, amine, or bromine) was introduced via straightforward chemical transformations.
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Affiliation(s)
- Maria Fridén-Saxin
- Department of Chemistry, Medicinal Chemistry, University of Gothenburg, SE-41296 Goteborg, Sweden
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Frejd T, Widegren M, Dietz M, Friberg A, Hahn-Hägerdal B, Gorwa-Grauslund M, Katz M. The Synthesis of Bicyclo[2.2.2]octan-2,6-dione Revisited. SYNTHESIS-STUTTGART 2006. [DOI: 10.1055/s-2006-942532] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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Friberg A, Johanson T, Franzén J, Gorwa-Grauslund MF, Frejd T. Efficient bioreduction of bicyclo[2.2.2]octane-2,5-dione and bicyclo[2.2.2]oct-7-ene-2,5-dione by genetically engineered Saccharomyces cerevisiae. Org Biomol Chem 2006; 4:2304-12. [PMID: 16729141 DOI: 10.1039/b603500k] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A screening of non-conventional yeast species and several Saccharomyces cerevisiae (baker's yeast) strains overexpressing known carbonyl reductases revealed the S. cerevisiae reductase encoded by YMR226c as highly efficient for the reduction of the diketones 1 and 2 to their corresponding hydroxyketones 3-6 (Scheme 1) in excellent enantiomeric excesses. Bioreduction of 1 using the genetically engineered yeast TMB4100, overexpressing YMR226c, resulted in >99% ee for hydroxyketone (+)-4 and 84-98% ee for (-)-3, depending on the degree of conversion. Baker's yeast reduction of diketone 2 resulted in >98% ee for the hydroxyketones (+)-5 and (+)-6. However, TMB4100 led to significantly higher conversion rates (over 40 fold faster) and also a minor improvement of the enantiomeric excesses (>99%).
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Affiliation(s)
- Annika Friberg
- Division of Organic Chemistry, Center for Chemistry and Chemical Engineering, Lund University, P.O. Box 124, SE-221 00 Lund, Sweden
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Lindberg J, Lindfors K, Setälä T, Kaivola M, Friberg A. Spectral analysis of resonant transmission of light through a single sub-wavelength slit. Opt Express 2004; 12:623-632. [PMID: 19474865 DOI: 10.1364/opex.12.000623] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
We analyze the spectral properties of resonant transmission of light through a sub-wavelength slit in a metal film. We show that the enhanced transmission can be understood in terms of interfering surface-wave-like modes propagating in the slit. We characterize the effect of geometrical and material properties of the slit on the transmission spectrum. Furthermore, we show that the wavelength of the transmission resonance strongly depends on the surrounding medium. This effect may be utilized in sensors, imaging, and the detection of, e.g. biomolecules.
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Thunberg L, Allenmark S, Friberg A, Ek F, Frejd T. Evaluation of two pairs of chiral stationary phases: Effects from the length of the achiral spacers. Chirality 2004; 16:614-24. [PMID: 15390085 DOI: 10.1002/chir.20080] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two pairs of chiral stationary phases (CSPs) with different C(2)-symmetric central parts were prepared and evaluated by chromatography of a series of structurally different racemates. Within each pair, the selectors on which the CSPs are based had different lengths of their achiral spacers. The CSPs based on selectors with short spacers showed higher enantioselectivity than the phases incorporating long spacers. On one pair of the phases, a study of the influence from different retention modifiers was performed for a series of benzodiazepinones. This demonstrated the importance of the polymer structure formed from the selectors with different spacer lengths for the enantiodiscriminating ability of the CSPs.
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Affiliation(s)
- Linda Thunberg
- Department of Chemistry, Göteborg University, SE-412 96 Göteborg, Sweden
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Billig H, Markström E, Svensson EC, Shao R, Friberg A. Follicular development and apoptosis. Ernst Schering Res Found Workshop 2003:23-41. [PMID: 12402538 DOI: 10.1007/978-3-662-04960-0_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/27/2023]
Affiliation(s)
- H Billig
- Department of Physiology, Göteborg University, P.O. Box 434, 40530 Göteborg, Sweden.
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Bergendal L, Friberg A, Schaffrath AM, Holmdahl M, Landahl S. The clinical relevance of the interaction between carbamazepine and dextropropoxyphene in elderly patients in Gothenburg, Sweden. Eur J Clin Pharmacol 1998; 53:203-6. [PMID: 9476032 DOI: 10.1007/s002280050363] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
OBJECTIVES To evaluate the clinical importance of the interaction between carbamazepine (CBZ) and dextropropoxyphene in elderly patients. METHODS All patients (n = 7263) in Gothenburg, Sweden, who were part of a drug-dispensing programme, were included in the study. Eight per cent of the patients took CBZ and 18% took dextropropoxyphene, continuously. Patients who used a combination of these drugs were compared with patients who took only CBZ or dextropropoxyphene or neither of the two drugs. These four groups of patients were matched to each other with reference to gender, age and concomitant medication, which finally resulted in 21 patients in each group. A questionnaire with 30 symptoms of well-being, including symptoms typical of adverse effects of CBZ, were answered by the patients with the help of a registered nurse. Venous blood samples were drawn from the patients for the analysis of CBZ, its metabolite CBZ 10,11-epoxide (CBZ-E) and dextropropoxyphene. RESULTS The doses of CBZ and dextropropoxyphene were lower among patients who used the combination of the two drugs than among those who only used one of the drugs. The mean level of CBZ in serum (S-CBZ) was, however, significantly higher and the level of CBZ-E in serum (S-CBZ-E) significantly lower among the patients who used the combination of CBZ and dextropropoxyphene, thus indicating an inhibition of the metabolism of CBZ. The prevalence of symptoms indicating side effects of CBZ was significantly higher in the group of patients who used both drugs. CONCLUSION This study has shown that the combination of CBZ and dextropropoxyphene is hazardous in elderly patients and should be used with caution.
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Affiliation(s)
- L Bergendal
- Pharmacy Department, Sahlgrenska University Hospital, Göteborg, Sweden
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Bergendal L, Friberg A, Schaffrath A. Potential drug--drug interactions in 5,125 mostly elderly out-patients in Gothenburg, Sweden. Pharm World Sci 1995; 17:152-7. [PMID: 8574210 DOI: 10.1007/bf01879709] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Of 5,125 mostly elderly out-patients, average age 78.2 years, 1,594 (31%) had at least one interacting drug combination according to the Swedish National Formulary. On average, each patient with drug-drug interactions (DDIs) had 1.6 DDIs. There was no difference in the sex or age between those having DDIs and those without. However, patients with one or more DDIs used a significantly larger number of drugs than those without DDIs, on average 8.1 versus 5.2. This significant difference was independent of age and sex. When classified for clinical significance according to the handbook "Drug Interactions and Updates" by Hansten and Horn, 155 (3%) patients had interactions of 'major clinical significance'. The most common were interactions between beta-adrenergic blockers and antidiabetics, followed by potassium-sparing diuretics and potassium, and carbamazepine and dextropropoxyphene. The methodology allows us to screen routinely for DDIs and to plan further studies with emphasis on clinical outcome.
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Affiliation(s)
- L Bergendal
- Pharmacy Department, Sahlgrenska University Hospital, Göteborg, Sweden
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Friberg A. [A warning about risk of errors when prescribing Losec!]. Lakartidningen 1991; 88:3172. [PMID: 1921607] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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Friberg A, Johansson R, Malmberg E. [Use of fluoride as a caries preventive over a 10-year period]. Tandlakartidningen 1989; 81:772-82. [PMID: 2634889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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Friberg A, Johansson R, Malmberg E. [Prescriptions written by dentists in Göteborg]. Tandlakartidningen 1987; 79:565-75. [PMID: 3474803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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