1. |
- B Jensen, Irene, et al.
(author)
-
Promoting Evidence-Based Practice for Improved Occupational Safety and Health at Workplaces in Sweden. Report on a Practice-Based Research Network Approach.
- 2020
-
In: International Journal of Environmental Research and Public Health. - : MDPI. - 1661-7827 .- 1660-4601. ; 17:15
-
Journal article (peer-reviewed)abstract
- Despite the rapid growth in research and R&D expenditures, the translation of research into practice is limited. One approach to increase the translation and utilization of research is practice based research networks. With the aim of strengthening evidence-based practice (EBP) within occupational health services in Sweden (OH-Services), a practice-based research network (PBRN-OSH) was developed. The PBRN-OSH includes researchers and representatives from end-users. This paper reports on the development, outputs and lessons learned in the PBRN-OSH. The PBRN-OSH resulted in several practice-based research projects as well as different measures to ensure EBP in OSH such as the governmentally sanctioned national guidelines for the OH-services. Moreover, results show that the competence in EBP increased among practitioners at the OH-services. Conducting research in a PBRN is more resource demanding; however, this does not imply that it is less cost effective. To succeed in increasing the utility of research findings via PBRN, resources must be invested into an infrastructure that supports collaboration in the PBRN, including costs for a variety of means of dissemination. Further, translation activities need to be included in academic career paths and reward systems if a major improvement in the impact and return of investments from research is to be expected.
|
|
2. |
- Elinder, Malin, et al.
(author)
-
Experimental Validation of a Fragment Library for Lead Discovery Using SPR Biosensor Technology
- 2011
-
In: Journal of Biomolecular Screening. - : Elsevier BV. - 1087-0571 .- 1552-454X. ; 16:1, s. 15-25
-
Journal article (peer-reviewed)abstract
- A new fragment library for lead discovery has been designed and experimentally validated for use in surface plasmon resonance (SPR) biosensor-based screening. The 930 compounds in the library were selected from 4.6 million commercially available compounds using a series of physicochemical and medicinal chemistry filters. They were screened against 3 prototypical drug targets: HIV-1 protease, thrombin and carbonic anhydrase, and a nontarget: human serum albumin. compound solubility was not a problem under the conditions used for screening. The high sensitivity of the sensor surfaces allowed the detection of interactions for 35% to 97% of the fragments, depending on the target protein. None of the fragments was promiscuous (i.e., interacted with a stoichiometry ≥5:1 with all 4 proteins), and only 2 compounds dissociated slowly from all 4 proteins. The use of several targets proved valuable since several compounds would have been disqualified from the library on the grounds of promiscuity if fewer target proteins had been used. The experimental procedure allowed an efficient evaluation and exploration of the new fragment library and confirmed that the new library is suitable for SPR biosensor-based screening.
|
|
3. |
- Elinder, Malin, et al.
(author)
-
Inhibition of HIV-1 by non-nucleoside reverse transcriptase inhibitors via an induced fit mechanism : Importance of slow dissociation and relaxation rates for antiviral efficacy
- 2010
-
In: Biochemical Pharmacology. - : Elsevier BV. - 0006-2952 .- 1356-1839. ; 80:8, s. 1133-1140
-
Journal article (peer-reviewed)abstract
- The importance of slow dissociation of non-nucleoside reverse transcriptase inhibitors (NNRTIs) for antiviral effect has been investigated. The kinetic characteristics of a series of NNRTIs interacting with wild type and drug resistant variants of HIV-1 RT (EC 2.7.7.49) were analyzed by SPR biosensor technology. The antiviral effect was determined in MT-4 and peripheral blood mononuclear cells. Due to extremely slow dissociation rates and a complex interaction mechanism, rate constants could not be quantified. Instead, interaction characteristics were qualitatively analyzed using simulated sensorgrams. The simplest model describing these interactions adequately was an induced fit mechanism, i.e. a mechanism involving the formation of an initial enzyme-inhibitor complex subsequently transformed into a more stable complex. Differences in rates of dissociation from the initial complex and rates of relaxation from the induced complex explained (1) the differences in the amounts of formed complex, (2) the stability of the complex and (3) the antiviral efficacies of the compounds. The effect of NNRTI binding site mutations also correlated with these kinetic characteristics. MIV-170 was the most effective inhibitor of wild type and mutant HIV-1 in cell culture, a property that was associated with the formation of the largest amount of complex and the slowest relaxation and dissociation rates. This study supports the hypothesis that the efficacy of anti-HIV drugs is dependent on slow dissociation from the target, thereby maximizing the duration of the inhibitory effect. It also illustrates the strength of simulating interaction data for qualitative analysis of tight-binding drugs and the importance of resolving the kinetic mechanism of drug-target interactions.
|
|
4. |
- Elinder, Malin, et al.
(author)
-
MIV-170 : A novel NNRTI exhibiting tight binding to HIV-1 reverse transcriptase (RT)
- 2008
-
In: Antiviral Research. - : Elsevier BV. - 0166-3542.
-
Conference paper (peer-reviewed)abstract
- The NNRTI MIV-170 has been found to be a very efficient inhibitor of wtHIV and HIV mutant strains resistant to the NNRTIs used in the clinic. To better understand the interaction between MIV-170 and HIV-1 the details of this have been studied by different methods. The kinetics of the interaction between MIV-170 and HIV-1 RT was analysed using a biosensor assay. The association and dissociation rates were determined using immobilized wtRT or RT mutants and MIV-170 as analyte. The results demonstrated that MIV-170 had both a faster association and a slower dissociation rate than efavirenz, nevirapine and delavirdine, thus exhibiting a higher affinity than these compounds. The strength of the interaction between the NNRTIs and RT and RT mutants in the biosensor assay was compared to the reversibility of inhibition in cell culture experiments. In these experiments virus and infected cells were incubated with MIV-170 and other NNRTIs for various times and after removal of the compounds the remaining infectivity was assayed. X-ray analysis of the binding of MIV-170 to HIV-1 RT displayed extensive interactions, not only between the compound and the lining amino acids but also between these residues, turning the binding cavity into a rigid entity and explaining the tight binding in the biosensor assay and the inactivation of HIV.
|
|
5. |
|
|
6. |
- Elinder, Malin, 1977-, et al.
(author)
-
Screening for NNRTIs with Slow Dissociation and High Affinity for a Panel of HIV-1 RT Variants
- 2009
-
In: Journal of Biomolecular Screening. - : SAGE. - 1087-0571 .- 1552-454X. ; 14:4, s. 395-403
-
Journal article (peer-reviewed)abstract
- A lead optimization library consisting of 800 HIV-1 nonnucleoside reverse transcriptase inhibitors (NNRTIs) was screened in parallel against 4 clinically relevant variants of HIV-1 RT (Wt, L100I, Y181C, and K103N) using a surface plasmon resonance-based biosensor. the aim was to identify inhibitors suitable in specific topical microbicides efficient for preventing the transmission of a range of clinically significant strains of HIV-1. the authors hypothesized that such compounds should have high affinity and slow dissociation rates for multiple variants of the target. to efficiently analyze the large amount of real-time data (sensorgrams) that were generated in the screening, they initially used signals from 3 selected time points to identify compounds with high affinity and slow dissociation for the complete panel of enzyme variants. hits were confirmed by visually inspecting the complete sensorgrams. two structurally unrelated compounds fulfilled the hit criteria, but only 1 compound was found to (a) compete with a known NNRTI for binding to the NNRTI site, (b) inhibit HIV-1 RT activity, and (c) inhibit HIV-1 replication in cell culture, for all 4 enzyme variants. this novel screening methodology offers high-resolution real-time kinetic data for multiple targets in parallel. it is expected to have broad applicability for the discovery of compounds with defined kinetic profiles, crucial for optimal therapeutic effects.
|
|
7. |
- Elinder, Malin
(author)
-
Towards a New Generation of Anti-HIV Drugs : Interaction Kinetic Analysis of Enzyme Inhibitors Using SPR-biosensors
- 2011
-
Doctoral thesis (other academic/artistic)abstract
- As of today, there are 25 drugs approved for the treatment of HIV and AIDS. Nevertheless, HIV continues to infect and kill millions of people every year. Despite intensive research efforts, both a vaccine and a cure remain elusive and the long term efficacy of existing drugs is limited by the development of resistant HIV strains. New drugs and preventive strategies that are effective against resistant virus are therefore still needed. In this thesis an enzymological approach, primarily using SPR-based interaction kinetic analysis, has been used for identification and characterization of compounds of potential use in next generation anti-HIV drugs. By screening of a targeted non-nucleoside reverse transcriptase inhibitor (NNRTI) library, one novel and highly potent NNRTI was identified. The inhibitor was selected with respect to resilience to drug resistance and for high affinity and slow dissociation – a kinetic profile assumed to be suitable for inhibitors used in topical microbicides. In order to confirm the hypothesis that such a kinetic profile would result in an effective preventive agent with long-lasting effect, the correlation between antiviral effect and kinetic profile was investigated for a panel of NNRTIs. The kinetic profiles revealed that NNRTI efficacy is dependent on slow dissociation from the target, although the induced fit interaction mechanism prevented quantification of the rate constants. To avoid cross-resistance, the next generation anti-HIV drugs should be based on chemical entities that do not resemble drugs in clinical use, either in structure or mode-of-action. Fragment-based drug discovery was used for identification of structurally new inhibitors of HIV-enzymes. One fragment that was effective also on variants of HIV RT with resistance mutations was identified. The study revealed the possibility of identifying structurally novel NNRTIs as well as fragments interacting with other sites of the protein. The two compounds identified in this thesis represent potential starting points for a new generation of NNRTIs. The applied methodologies also show how interaction kinetic analysis can be used as an effective and versatile tool throughout the lead discovery process, especially when integrated with functional enzymological assays.
|
|
8. |
- Geitmann, Matthis, et al.
(author)
-
Identification of a Novel Scaffold for Allosteric Inhibition of Wild Type and Drug Resistant HIV-1 Reverse Transcriptase by Fragment Library Screening
- 2011
-
In: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 54:3, s. 699-708
-
Journal article (peer-reviewed)abstract
- A novel scaffold inhibiting wild type and drug resistant variants of human immunodeficiency virus type 1 reverse transcriptase (HIV-1RT) has been identified in a library consisting of 1040 fragments. The fragments were significantly different from already known non-nucleoside reverse transcriptase inhibitors (NNRTIs), as indicated by a Tversky similarity analysis. A screening strategy involving SPR biosensor-based interaction analysis and enzyme inhibition was used. Primary biosensor-based screening, using short concentration series, was followed by analysis of nevirapine competition and enzyme inhibition, thus identifying inhibitory fragments binding to the non-nucleoside reverse transcriptase inhibitor (NNRTI) binding site. Ten hits were discovered, and their affinities and resistance profiles were evaluated with wild type and three drug resistant enzyme variants (K103N, Y181C, and L100I). One fragment exhibited submillimolar K(D) and IC(50) values against all four tested enzyme variants. A substructure comparison between the fragment and 826 structurally diverse published NNRTIs confirmed that the scaffold was novel. The fragment is a bromoindanone with a ligand efficiency of 0.42 kcal/mol(-1).
|
|
9. |
- Jakesova, Marie, et al.
(author)
-
Optoelectronic control of single cells using organic photocapacitors
- 2019
-
In: Science Advances. - Washington, DC, United States : American Association for the Advancement of Science (A A A S). - 2375-2548. ; 5:4
-
Journal article (peer-reviewed)abstract
- Optical control of the electrophysiology of single cells can be a powerful tool for biomedical research and technology. Here, we report organic electrolytic photocapacitors (OEPCs), devices that function as extracellular capacitive electrodes for stimulating cells. OEPCs consist of transparent conductor layers covered with a donor-acceptor bilayer of organic photoconductors. This device produces an open-circuit voltage in a physiological solution of 330 mV upon illumination using light in a tissue transparency window of 630 to 660 nm. We have performed electrophysiological recordings on Xenopus laevis oocytes, finding rapid (time constants, 50 mu s to 5 ms) photoinduced transient changes in the range of 20 to 110 mV. We measure photoinduced opening of potassium channels, conclusively proving that the OEPC effectively depolarizes the cell membrane. Our results demonstrate that the OEPC can be a versatile nongenetic technique for optical manipulation of electrophysiology and currently represents one of the simplest and most stable and efficient optical stimulation solutions.
|
|
10. |
- Liin, Sara, et al.
(author)
-
Polyunsaturated fatty acid analogs act antiarrhythmically on the cardiac I-Ks channel
- 2015
-
In: Proceedings of the National Academy of Sciences of the United States of America. - : National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 112:18, s. 5714-5719
-
Journal article (peer-reviewed)abstract
- Polyunsaturated fatty acids (PUFAs) affect cardiac excitability. Kv7.1 and the beta-subunit KCNE1 form the cardiac I-Ks channel that is central for cardiac repolarization. In this study, we explore the prospects of PUFAs as I-Ks channel modulators. We report that PUFAs open Kv7.1 via an electrostatic mechanism. Both the polyunsaturated acyl tail and the negatively charged carboxyl head group are required for PUFAs to open Kv7.1. We further show that KCNE1 coexpression abolishes the PUFA effect on Kv7.1 by promoting PUFA protonation. PUFA analogs with a decreased pK(a) value, to preserve their negative charge at neutral pH, restore the sensitivity to open I-Ks channels. PUFA analogs with a positively charged head group inhibit I-Ks channels. These different PUFA analogs could be developed into drugs to treat cardiac arrhythmias. In support of this possibility, we show that PUFA analogs act antiarrhythmically in embryonic rat cardiomyocytes and in isolated perfused hearts from guinea pig.
|
|