| 1. |
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| 2. |
- Dahlqvist, Johanna, 1979-, et al.
(författare)
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Identification and functional characterization of a novel susceptibility locus for small vessel vasculitis with MPO-ANCA
- 2022
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Ingår i: Rheumatology. - Oxford, United Kingdom : Oxford University Press (OUP). - 1462-0324 .- 1462-0332. ; 61:8, s. 3461-3470
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Tidskriftsartikel (refereegranskat)abstract
- Objective To identify and characterize genetic loci associated with the risk of developing ANCA-associated vasculitides (AAV). Methods Genetic association analyses were performed after Illumina sequencing of 1853 genes and subsequent replication with genotyping of selected single nucleotide polymorphisms in a total cohort of 1110 Scandinavian cases with granulomatosis with polyangiitis or microscopic polyangiitis, and 1589 controls. A novel AAV-associated single nucleotide polymorphism was analysed for allele-specific effects on gene expression using luciferase reporter assay. Results PR3-ANCA(+) AAV was significantly associated with two independent loci in the HLA-DPB1/HLA-DPA1 region [rs1042335, P = 6.3 x 10(-61), odds ratio (OR) 0.10; rs9277341, P = 1.5 x 10(-44), OR 0.22] and with rs28929474 in the SERPINA1 gene (P = 2.7 x 10(-10), OR 2.9). MPO-ANCA(+) AAV was significantly associated with the HLA-DQB1/HLA-DQA2 locus (rs9274619, P = 5.4 x 10(-25), OR 3.7) and with a rare variant in the BACH2 gene (rs78275221, P = 7.9 x 10(-7), OR 3.0), the latter a novel susceptibility locus for MPO-ANCA(+) granulomatosis with polyangiitis/microscopic polyangiitis. The rs78275221-A risk allele reduced luciferase gene expression in endothelial cells, specifically, as compared with the non-risk allele. Conclusion We identified a novel susceptibility locus for MPO-ANCA(+) AAV and propose that the associated variant is of mechanistic importance, exerting a regulatory function on gene expression in specific cell types.
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| 3. |
- Herek, Jennifer, et al.
(författare)
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Ultrafast carotenoid band shifts: Experiment and theory
- 2004
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Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 108:29, s. 10398-10403
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Tidskriftsartikel (refereegranskat)abstract
- The ultrafast carotenoid band shift upon excitation of nearby bacteriochlorophyll molecules was studied in three different light harvesting complexes from purple bacteria. The results were analyzed in terms of changes in local electric field of the carotenoids. Time dependent density functional theory calculations based on known and model structures led to good agreement with experimental results, strongly suggesting that the mutual orientation of the pigment molecules rather than the type of the carotenoid molecules determines the extent of the ultrafast band shift. We further estimate that the protein induced local field nearby carotenoid molecule is about 4 or 6 MV/cm, depending on the orientation of the change of the electrical dipole in the carotenoid upon optical transition.
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| 4. |
- Laurell, H., et al.
(författare)
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Continuous-variable quantum state tomography of photoelectrons
- 2022
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Ingår i: Physical Review Research. - 2643-1564. ; 4:3
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Tidskriftsartikel (refereegranskat)abstract
- We propose a continuous variable quantum state tomography protocol of electrons which result from the ionization of atoms or molecules by the absorption of extreme ultraviolet light pulses. Our protocol is benchmarked against a direct calculation of the quantum state of photoelectrons ejected from helium and argon in the vicinity of a Fano resonance. In the latter case, we furthermore distill ion-photoelectron entanglement due to spin-orbit splitting. This opens routes toward the investigation of quantum coherence and entanglement properties on the ultrafast timescale.
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| 5. |
- Van Hoovels, L., et al.
(författare)
-
IgA rheumatoid factor in rheumatoid arthritis
- 2022
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Ingår i: Clinical Chemistry and Laboratory Medicine. - : Walter de Gruyter GmbH. - 1434-6621 .- 1437-4331. ; 60:10, s. 1617-1626
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Tidskriftsartikel (refereegranskat)abstract
- Objectives Rheumatoid factor (RF) is a well-established marker for the diagnosis and classification of rheumatoid arthritis (RA). Most studies evaluated IgM RF or isotype-nonspecific total RF assays. We evaluated the added value of IgA RF in this context. Methods An international sample cohort consisting of samples from 398 RA patients and 1073 controls was tested for IgA RF with 3 commercial assays. For all RA patients and 100 controls essential clinical and serological data for ACR/EULAR classification were available. Results The sensitivity of IgA RF for diagnosing RA was lower than the sensitivity of IgM RF. Differences in numerical values between IgA RF assays were observed. With all assays, the highest IgA RF values were found in patients with primary Sjogren's syndrome. Double positivity for IgM RF and IgA RF had a higher specificity for RA than either IgM RF or IgA RF. The sensitivity of double positivity was lower than the sensitivity of either IgA RF or IgM RF. Single positivity for IgA RF was at least as prevalent in controls than in RA patients. Adding IgA RF to IgM RF and anti-citrullinated protein antibodies (ACPA) did not affect RA classification. However, combined positivity for IgA RF, IgM RF and IgG ACPA had a higher specificity and lower sensitivity for RA classification than positivity for either of the antibodies. Conclusions IgA RF showed a lower sensitivity than IgM RF. Combining IgA RF with IgM RF and ACPA did not improve sensitivity of RA classification. Combined positivity (IgA-RF/IgM-RF/ACPA) increased specificity.
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| 6. |
- Van Hoovels, L., et al.
(författare)
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Multicentre study to improve clinical interpretation of rheumatoid factor and anti-citrullinated protein/peptide antibodies test results
- 2022
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Ingår i: RMD Open. - : BMJ. - 2056-5933. ; 8:1
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Rheumatoid factor (RF) and anti-citrullinated protein/peptide antibodies (ACPA) are important biomarkers for diagnosis of rheumatoid arthritis (RA). However, there is poor harmonisation of RF and ACPA assays. The aim of this study was to refine RF and ACPA interpretation across commercial assays. MATERIALS AND METHODS: Six total RF isotype-non-specific assays, 3 RF IgM isotype-specific assays and 9 ACPA immunoglobulin G assays of 13 different companies were evaluated using 398 diagnostic samples from patients with RA and 1073 disease controls. RESULTS: Using cut-offs proposed by the manufacturer, there was a large variability in diagnostic sensitivity and specificity between assays. Thresholds of antibody levels were determined based on predefined specificities and used to define test result intervals. Test result interval-specific likelihood ratios (LRs) were concordant across the different RF and ACPA assays. For all assays, the LR for RA increased with increasing antibody level. Higher LRs were found for ACPA than for RF. ACPA levels associated with LRs >80 were found in a substantial fraction (>22%) of patients with RA. CONCLUSION: Defining thresholds for antibody levels and assigning test result interval-specific LRs allows alignment of clinical interpretation for all RF and ACPA assays. © Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.
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| 7. |
- Van Hoovels, L., et al.
(författare)
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Standardisation of ACPA tests: evaluation of a new candidate reference preparation
- 2022
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Ingår i: Annals of the Rheumatic Diseases. - : BMJ. - 0003-4967 .- 1468-2060. ; 81:10, s. 1379-1384
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Tidskriftsartikel (refereegranskat)abstract
- Introduction Commercial assays measuring antibodies to citrullinated protein/peptide (ACPA) show poor quantitative agreement. The diagnostic industry has never adopted the International Union of Immunological Societies-Centers for Disease Control and Prevention (IUIS-CDC) ACPA reference standard. Recently, the National Institute for Biological Standards and Control (NIBSC) prepared a new candidate ACPA standard (18/204). We evaluated both reference materials using different commercially available ACPA assays. Materials and methods This is an international study in which the NIBSC candidate ACPA standard and the IUIS-CDC ACPA reference material were analysed together with 398 diagnostic samples from individuals with rheumatoid arthritis (RA) and in 1073 individuals who did not have RA using nine commercial ACPA assays. Results For both reference materials and samples from individuals with RA and individuals who did not have RA, there were large differences in quantitative ACPA results between assays. For most assays, values for the IUIS-CDC standard were lower than values for NIBSC 18/204 and the IUIS-CDC/NIBSC ratio was comparable for several, but not all assays. When NIBSC 18/204 was used as a calibrator, an improvement in alignment of ACPA results across several of the evaluated assays was obtained. Moreover, NIBSC 18/204 could align clinical interpretation for some but not all assays. Conclusion Adoption of an international standard for ACPA determination is highly desirable. The candidate NIBSC 18/204 standard improved the standardisation and alignment of most ACPA assays and might therefore be recommended to be used as reference in commercial assays.
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| 8. |
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| 9. |
- Brotonsc, Carlos, et al.
(författare)
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Prevention and health promotion in clinical practice: the views of general practitioners in Europe.
- 2005
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Ingår i: Preventive medicine. - : Elsevier BV. - 0091-7435. ; 40:5, s. 595-601
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Disease prevention and health promotion are important tasks in the daily practice of all general practitioners (GPs). The objective of this study was to explore the knowledge and attitudes of European GPs in implementing evidence-based health promotion and disease prevention recommendations in primary care, to describe GPs' perceived barriers to implementing these recommendations and to assess how GPs' own health behaviors affect their work with their patients. METHODS: A postal multinational survey was carried out from June to December 2000 in a random sample of GPs listed from national colleges of each country. RESULTS: Eleven European countries participated in the study, giving a total of 2082 GPs. Although GPs believe they should advise preventive and health promotion activities, in practice, they are less likely to do so. About 56.02% of the GPs answered that carrying-out prevention and health promotion activities are difficult. The two most important barriers reported were heavy workload/lack of time and no reimbursement. Associations between personal health behaviour and attitudes to health promotion or activities in prevention were found. GPs who smoked felt less effective in helping patients to reduce tobacco consumption than non-smoking GPs (39.34% versus 48.18%, P < 0.01). GPs who exercised felt that they were more effective in helping patients to practice regular physical exercise than sedentary GPs (59.14% versus 49.70%, P < 0.01). CONCLUSIONS: Significant gaps between GP's knowledge and practices persist in the use of evidence-based recommendations for health promotion and disease prevention in primary care.
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| 10. |
- Eriksson, Axl, et al.
(författare)
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Synthesis of Well-Ordered Functionalized Silicon Microwires Using Displacement Talbot Lithography for Photocatalysis
- 2024
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Ingår i: ACS Omega. - : American Chemical Society (ACS). - 2470-1343. ; 9:18, s. 20623-20628
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Tidskriftsartikel (refereegranskat)abstract
- Metal-assisted chemical etching (MACE) is a cheap and scalable method that is commonly used to obtain silicon nano- or microwires but lacks spatial control. Herein, we present a synthesis method for producing vertical and highly periodic silicon microwires, using displacement Talbot lithography before wet etching with MACE. The functionalized periodic silicon microwires show 65% higher PEC performance and 2.3 mA/cm2 higher net photocurrent at 0 V compared to functionalized, randomly distributed microwires obtained by conventional MACE at the same potentials.
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| 11. |
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| 12. |
- Erlandsson, M, et al.
(författare)
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TRANSCRIPTIONAL ACTIVITY OF SURVIVIN CONTRIBUTES TO MATURATION AND FUNCTION OF THE INTERFERON-GAMMA PRODUCING T CELLS IN RHEUMATOID ARTHRITIS
- 2020
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Ingår i: ANNALS OF THE RHEUMATIC DISEASES. - : BMJ. - 0003-4967 .- 1468-2060. ; 79, s. 83-84
-
Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Interferon gamma (IFNg) signalling and downstream effects make important contribution in pathogenesis of rheumatoid arthritis (RA). Here, we propose a mechanism by which oncoprotein survivin participates in development of IFN-dependent repertoire of T cells in RA patients.Objectives:We study the role of survivin in the phenotype of CD4 T cells of RA patients.Methods:CD4 cells of RA patients and healthy controls were purified from blood, activated and subjected to RNAseq, ChIPseq with antibodies to survivin (BIRC5) was performed on CD4+ cells. Histone H3 ChIPseq was performed using antibodies to H3K27ac, H3K27me3 and H3K4me3. Statistical analysis was performed In R-studio using the Bioconductor package DESeq2, clustering using Spearman and Ward.D2.Results:Unsupervised clustering of CD4 samples by expression of 48 core Th cell markers identified subsets of CD28hiCD27hiIFNnegcentral memory cells (Tcm), CD28loCD27loIFNloeffector memory cells (Tem) and CD28nullCD27nullIFNhiterminal effector cells (Tte). Tte cells showed classical features of Th1 cells including high levels of TBX21, TNFa and IL32 and signs of activation in IFN signalling machinery. Interestingly, they combined the features of peripheral Tregs CD25hiFoxp3hiIKZF2negand IL10 producing cells together with type 1 regulatory cells, which rely on transcription factors BATF and IRF1 for the differentiation and produced high amounts of perforin and granzyme B. Importantly, Tte CD4 cells had also high transcription of BIRC5 (p=1.15e-18).To study if BIRC5 is a part of IFN signalling, CD4 cells were cultured with survivin inhibitor YM155 and activated with IFNg. RNAseq analysis revealed 2033 (FC<2.0, n=336) differentially expressed genes in the IFN stimulated cultures. Interestingly, a substantial number of these IFN-dependent genes was significantly reduced in the survivin-deficient cultures and included among others CD28, FoxP3, IKZF2, ICOS, BATF, PRDM1, CXCR3, IRF4 and IRF8. Analysis of the peak sequences identified enrichment for composite motifs for IRFs (ETS:IRF, p1.0e-124; bZIP:IRF, p=1.0e-640), indicating that survivin is important for IFNg signalling. Numerically, the peaks containing ETS:IRF motifs were most prevalent and identified in total within 49.7% of all survivin-ChIP peaks. Frequent was co-localisation of the IRF:bZIP and IRF:ETS motifs within the survivin peaks. Among the IRF motifs dominated those suitable for IRF1 (p=1,0e-127) and IRF8 (p=1,0e-84). However, the DNA binding motifs of these two are alike.Encouraged by the survivin ChIPseq results, we wanted to know its relation to histone marks. We observed that 50% of survivin peaks containing both IRF:bZIP and IRF:ETS motifs are co-localized with the H3K27ac marks. In total, 16 of 48 core Th cell markers used for patients clustering were identified by survivin ChIPseq, co-localized with IRF composite motifs and histone marks. They were also dependent of survivin for expression.Conclusion:his study showed that survivin binds to DNA and regulates the core gene expression contributing to maturation and function of the IFNg producing Th1 cells.References:-Disclosure of Interests:Malin Erlandsson: None declared, Karin ME Andersson: None declared, Nisha Nair: None declared, Anastasius Damdimopoulos: None declared, Sofia Töyrä Silfverswärd: None declared, Rille Pullerits: None declared, Anne Barton Consultant of: AbbVie, Maria I Bokarewa: None declared
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| 13. |
- Hennings, Viktoria, et al.
(författare)
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The presence of serum anti-SARS-CoV-2 IgA appears to protect primary health care workers from COVID-19.
- 2022
-
Ingår i: European journal of immunology. - : Wiley. - 1521-4141 .- 0014-2980. ; 52:5, s. 800-809
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Tidskriftsartikel (refereegranskat)abstract
- The patterns of humoral and cellular responses to SARS-CoV-2 were studied in Swedish primary health care workers (n = 156) for 6 months during the Covid-19 pandemic. Serum IgA and IgG to SARS-CoV-2, T-cell proliferation and cytokine secretion, demographic and clinical data, PCR-verified infection, and self-reported symptoms were monitored. The multivariate method OPLS-DA was used to identify immune response patterns coupled to protection from Covid-19. Contracting Covid-19 was associated with SARS-CoV-2-specific neutralizing serum IgG, T cell, IFN-γ, and granzyme B responses to SARS-CoV-2, self-reported typical Covid-19 symptoms, male sex, higher BMI, and hypertension. Not contracting Covid-19 was associated with female sex, IgA-dominated, or no antibody responses to SARS-CoV-2, airborne allergy, and smoking. The IgG-responders had SARS-CoV-2-specific T-cell responses including a cytotoxic CD4+ T-cell population expressing CD25, CD38, CD69, CD194, CD279, CTLA-4, and granzyme B. IgA-responders with no IgG response to SARS-CoV-2 constituted 10% of the study population. The IgA responses were partially neutralizing and only seen in individuals who did not succumb to Covid-19. To conclude, serum IgG-dominated responses correlated with T-cell responses to SARS-CoV-2 and PCR-confirmed Covid-19, whereas IgA-dominated responses correlated with not contracting the infection.
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| 14. |
- Jin, Tao, 1973, et al.
(författare)
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A novel mouse model for septic arthritis induced by Pseudomonas aeruginosa
- 2019
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 9
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Tidskriftsartikel (refereegranskat)abstract
- Septic arthritis is one of the most aggressive joint diseases. Although caused predominantly by S. aureus, Gram-negative bacteria, Pseudomonas aeruginosa among them, account for a significant percentage of the causal agents of septic arthritis. However, septic arthritis caused by P. aeruginosa has not been studied thus far, due to lack of an animal model. NMRI mice were inoculated with different doses of P. aeruginosa. The clinical course of septic arthritis and radiological changes of joints were examined. Furthermore, the host molecular and cellular mechanisms involved in P. aeruginosa-induced septic arthritis were investigated. Inoculation of mice with P. aeruginosa caused septic arthritis in a dose-dependent manner. Neutrophil depletion led to higher mortality and more severe joint destruction (p < 0.01). In contrast, monocyte depletion resulted in higher mortality (p < 0.05) but similar arthritis severity compared to controls. Mice depleted of CD4+ T-cells inoculated with P. aeruginosa displayed less severe bone damage (p < 0.05). For the first time, a mouse model for P. aeruginosa septic arthritis is presented. Our data demonstrate that neutrophils play a protective role in P. aeruginosa septic arthritis. Monocytes/macrophages, on the other hand, are only essential in preventing P. aeruginosa-induced mortality. Finally, CD4+ T-cells are pathogenic in P. aeruginosa septic arthritis.
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| 15. |
- Karki, Khadga Jung, et al.
(författare)
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Coherent two-dimensional photocurrent spectroscopy in a PbS quantum dot photocell.
- 2014
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Recently there has been growing interest in the role of coherence in electronic dynamics. Coherent multidimensional spectroscopy has been used to reveal coherent phenomena in numerous material systems. Here we utilize a recent implementation of coherent multidimensional spectroscopy-two-dimensional photocurrent spectroscopy-in which we detect the photocurrent from a PbS quantum dot photocell resulting from its interactions with a sequence of four ultrafast laser pulses. We observe sub-picosecond evolution of two-dimensional spectra consistent with multiple exciton generation. Moreover, a comparison with two-dimensional fluorescence spectra of the quantum dots demonstrates the potential of two-dimensional photocurrent spectroscopy to elucidate detailed origins of photocurrent generating electronic state coherence pathways. Since the measurement is based on detecting the photocell current in situ, the method is well suited to study the fundamental ultrafast processes that affect the function of the device. This opens new avenues to investigate and implement coherent optimization strategies directly within devices.
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| 16. |
- Karki, Khadga Jung, et al.
(författare)
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Digital cavities and their potential applications
- 2013
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- The concept of a digital cavity is presented. The functionality of a tunable radio-frequency/microwave cavity with unrestricted Q-factor is implemented. The theoretical aspects of the cavity and its potential applications in high resolution spectroscopy and synchronization of clocks together with examples in signal processing and data acquisition are discussed.
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| 17. |
- Kawai, M., et al.
(författare)
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Comparison of the efficacy of salmeterol/fluticasone propionate combination in Japanese and Caucasian asthmatics
- 2007
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Ingår i: Respir Med. - : Elsevier BV. - 0954-6111. ; 101:12, s. 2488-94
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION: The effect of ethnicity on the efficacy of salmeterol (S)+fluticasone propionate (FP) has not been examined in Japanese and Caucasian asthmatics. In this study, the efficacy of combination treatment with S and FP from a single inhaler (SFC) was compared with concurrent treatment with S and FP administration from separate inhalers (S+FP) in Japanese and Caucasian asthmatics. METHODS: This was a randomised, double-blind, crossover study in male and female Japanese (n=18) and Caucasian (n=17) asthmatics (50-100% predicted FEV(1); >35% reversibility in sGaw). Subjects received SFC (S 50mcg/FP 250mcgb.i.d.) and S+FP (S 50mcgb.i.d.+FP 250mcgb.i.d.) for 14 days. sGaw and FEV(1) were determined 0-12h after the first and last doses. RESULTS: Treatment with both SFC and S+FP produced marked bronchodilation, which was maintained 0-12h after the first dose. Baseline sGaw and FEV(1) increased up to 51% and 180mL, respectively, in Japanese subjects over 2 weeks of treatment, with similar improvements in Caucasian subjects. On Day 14 the 0-12h S+FP:SFC treatment ratios (90% CI) for sGaw AUC and peak were 1.05 (0.98, 1.12) and 1.05 (0.97, 1.14), respectively, in Japanese subjects, and 0.99 (0.92, 1.07) and 0.98 (0.89, 1.07), respectively, in Caucasian subjects, with no difference between the two ethnic groups. CONCLUSIONS: The finding of a similar significant bronchodilator response in Japanese and Caucasian asthmatics following concurrent and combination treatment with salmeterol and FP suggests that the therapeutic response to these agents is comparable and independent of ethnicity in Japanese and Caucasian asthma patients.
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| 18. |
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| 19. |
- Nagy, E., et al.
(författare)
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The impact of the COVID-19 pandemic on autoimmune diagnostics in Europe: A lesson to be learned
- 2021
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Ingår i: Autoimmunity Reviews. - : Elsevier BV. - 1568-9972. ; 20:12
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: The first wave of COVID-19 pandemic has disrupted almost all areas of the health care services to some extent throughout the world. Although the negative impact of COVID-19 on patients with autoimmune diseases has also been recognized, available data in this regard are limited. In the current study of the European Autoimmunity Standardisation Initiative (EASI) we aimed to provide reliable data on the extent of the impact of COVID-19 pandemic on test requests for different autoantibodies in European countries. Methods: Data on test numbers and on the number of positive results were collected in 97 clinical laboratories from 15 European countries on a monthly basis for the year before (2019) and the year during (2020) the COVID19 pandemic. Results: A reduction in the number of autoantibody tests was observed in all European countries in the year 2020 compared to 2019. The reduction affected all autoantibody tests with an overall decrease of 13%, ranging from 1.4% (Switzerland) to 25.5% (Greece). In all countries, the decrease was most pronounced during the first wave of the pandemic (March-May 2020) with an overall decrease in those three months of 45.2%. The most affected autoantibodies were those commonly requested by general practitioners (anti-tTG IgA (71%), RF IgM (66%) and ACPA (61%)). In the second wave of the pandemic (October-December 2020) the decrease was less pronounced (6.8%). With respect to the rate of positive results, subtle differences were observed for distinct autoantibodies during the pandemic, but the total rate of positive results was similar in both years. Conclusions: Our study demonstrated a strong decrease in autoantibody requests during the first wave of the COVID-19 pandemic in 15 European countries. The second wave was characterized by a less pronounced impact, with some participating countries hardly affected, while some other countries experienced a second decline. The decrease was clearly associated with the level of lock-down and with the required adjustments in the health care systems in different countries, supporting the importance of an effective strategy for the coordination of autoimmune testing in challenging situations as the COVID-19 pandemic.
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| 20. |
- Polivka, Tomas, et al.
(författare)
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Ultrafast formation of a carotenoid radical in LH2 antenna complexes of purple bacteria
- 2004
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Ingår i: The Journal of Physical Chemistry Part B. - : American Chemical Society (ACS). - 1520-5207 .- 1520-6106. ; 108:39, s. 15398-15407
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Tidskriftsartikel (refereegranskat)abstract
- The SI-mediated carotenoid to BChl a energy-transfer pathway and carotenoid radical formation have been studied using femtosecond time-resolved transient absorption spectroscopy. A series of LH2 complexes (LH2 = light-harvesting complex 2) from Rhodobacter sphaeroides incorporating carotenoids neurosporene, spheroidene, and spheroidenone were used to explore the effect of conjugation length. The S, lifetimes of carotenoids in the LH2 complex are significantly shorter than in solution, resulting in efficiencies of the S-1-mediated energy transfer of 94%, 82%, and 76%, respectively. In addition to the S-1 decay, a low-amplitude component of similar to9 ps was revealed for all carotenoids in LH2 and assigned to the S* state. Besides energy transfer, excitation of the carotenoid S-2 state in LH2 complexes also leads to the formation of a carotenoid radical, and this pathway is also conjugation length dependent. The carotenoid radical is formed as a result of electron transfer between the carotenoid and B800 BChl a molecules. The yield of the radical formation is highest for neurosporene (10-15%), while a lower efficiency was observed for spheroidene (5-8%). For spheroidenone, no distinct radical signal was found, The precursor of the carotenoid radical is a charge-transfer state that is populated directly from the S-2 state. This charge-transfer state, which represents an excited state of the carotenoid-B800 complex, decays in 300 fs (neurosporene) or 400 fs (spheroidene) to form ground-state carotenoid cation and BChl anion. The charge-separated state has a lifetime of 2 ps (neurosporene) and 8 ps (spheroidene).
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| 21. |
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| 22. |
- Rentzos, Georgios K., et al.
(författare)
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Use of a basophil activation test as a complementary diagnostic tool in the diagnosis of severe peanut allergy in adults
- 2015
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Ingår i: Clinical and Translational Allergy. - : Wiley. - 2045-7022. ; 5
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Diagnosis of severe peanut allergy is difficult and delays in making an accurate diagnosis may place the patient at risk. Adults with a history of anaphylaxis must strictly avoid any contact with peanuts or products that may contain traces of peanuts. For these persons, conventional evaluations with skin prick testing (SPT) and IgE tests may not be sufficient to assess the risk of anaphylaxis. Therefore, we investigated whether the basophil activation test (BAT) could be used for the diagnosis of severe peanut allergy in adults. We compared the non-invasive BAT with conventional laboratory diagnostic tests, including SPT and specific IgE to allergen extracts and components, for the diagnosis of severe peanut allergy. Methods: Forty-seven persons with severe allergy to peanuts and a clinical diagnosis of anaphylaxis (PA-group), 22 subjects with peanut sensitization (PS-group) and 22 control (C-group) subjects, all in the age range of 18-60 years, were recruited retrospectively and prospectively into the study. Thirty-four patients with peanut allergy and 11 peanut-sensitized patients were sensitized to soy, while 36 patients in the PA-group and 20 patients in the PS-group were sensitized to birch pollen. All the patients and control subjects were investigated with BAT and SPT for responses to peanut, soy and birch extracts and their serum samples were assayed for the presence of specific IgE to peanut, soy and birch extracts, as well as IgE to allergen components (ISAC). Results: In a multivariate factor analysis, severe peanut allergy (PA) was positively associated with SPT to peanut, IgE to peanut, BAT to peanut and IgE to rAra h 1, 2, 3 and 6 peanut components, as well as to soy components (nGly m 5 and nGly m 6). In contrast, peanut sensitization was positively associated with increased levels of IgE to rAra h 8, birch and birch-related components. BAT-detected reactivity to peanut was significantly higher in patients who had a history of severe allergy to peanuts, as compared with patients who were sensitized to peanuts (p < 0.001), and the receiver operating curve (ROC) analysis showed that BAT had high sensitivity and specificity for predicting severe peanut allergy, with a ROC area under the curve of 0.862. However, in the PA-group, the BAT results for peanut correlated only weakly with the levels of IgE to rAra h 1, 2 and 3 and nAra h 6. Study limitations: oral provocation in the patients with a history of severe peanut allergy could not be performed to compare clinical reactivity with the BAT result due to ethical constraints. Neither was it possible to perform BAT with peanut recombinant allergens which were not available at the time the study commenced Conclusions: BAT is useful in determining the severity of peanut allergy and may be used as a complementary diagnostic tool to ensure accurate diagnosis of severe peanut allergy in adults. Thus, it may reduce the need to subject these patients to further tests, including an open challenge with peanuts. © 2015 Rentzos et al.; licensee BioMed Central.
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| 23. |
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| 24. |
- Schubert, Axel, et al.
(författare)
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In vitro self-assembly of the light harvesting pigment-protein LH2 revealed by ultrafast spectroscopy and electron microscopy
- 2004
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Ingår i: Biophysical Journal. - 1542-0086. ; 86:4, s. 2363-2373
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Tidskriftsartikel (refereegranskat)abstract
- Controlled ensemble formation of protein-surfactant systems provides a fundamental concept for the realization of nanoscale devices with self-organizing capability. In this context, spectroscopic monitoring of pigment-containing proteins yields detailed structural information. Here we have studied the association behavior of the bacterial light-harvesting protein LH2 from Rhodobacter spheroides in an n,n-dimethyldodecylamine-n-oxide/water environment. Time-resolved studies of the excitation annihilation yielded information about aggregate sizes and packing of the protein complexes therein. The results are compared to transmission electron microscopy images of instantaneously frozen samples. Our data indicate the manifestation of different phases, which are discussed with respect to the thermodynamic equilibrium in ternary protein-surfactant-water systems. Accordingly, by varying the concentration the formation of different types of aggregates can be controlled. Conditions for the appearance of isolated LH2 complexes are defined.
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| 25. |
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| 26. |
- Wu, Fan, et al.
(författare)
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Optical cavity-mediated exciton dynamics in photosynthetic light harvesting 2 complexes
- 2022
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Ingår i: Nature Communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 13:1
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Tidskriftsartikel (refereegranskat)abstract
- Strong light-matter interaction leads to the formation of hybrid polariton states and alters the photophysical dynamics of organic materials and biological systems without modifying their chemical structure. Here, we experimentally investigated a well-known photosynthetic protein, light harvesting 2 complexes (LH2) from purple bacteria under strong coupling with the light mode of a Fabry-Perot optical microcavity. Using femtosecond pump probe spectroscopy, we analyzed the polariton dynamics of the strongly coupled system and observed a significant prolongation of the excited state lifetime compared with the bare exciton, which can be explained in terms of the exciton reservoir model. Our findings indicate the potential of tuning the dynamic of the whole photosynthetic unit, which contains several light harvesting complexes and reaction centers, with the help of strong exciton-photon coupling, and opening the discussion about possible design strategies of artificial photosynthetic devices.
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