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1.
Z Rheumatol ; 82(1): 71-81, 2023 Feb.
Artigo em Alemão | MEDLINE | ID: mdl-36424414

RESUMO

BACKGROUND: Gout is the most frequent inflammatory joint disease in the western world and has a proven genetic background. Additionally, lifestyle factors, such as increasing life expectation and standard of living, sufficient or excess nutrition and a growing prevalence of obesity in the population as well as e.g. alcohol consumption, contribute to the rising incidence of hyperuricemia and gout. Apart from an adequate medication, medical consultation on nutrition and lifestyle is an essential part of the management of gout patients, who have a high risk of internal comorbidities. OBJECTIVE: In 2015 the Austrian Society for Rheumatology and Rehabilitation (ÖGR) working group for osteoarthritis and crystal arthropathies published nutrition and lifestyle recommendations for patients with gout and hyperuricemia. Since then, a multitude of studies have been published addressing this topic, which necessitated an update. METHODS: First, the authors performed a hierarchical literature search to screen for the literature published since 2015. Considering references given in the first publication, the relevant literature was selected and the recommendations from 2015 were either kept as published, reformulated or recreated. Finally, the evidence level and the level of agreement for each recommendation were added by the authors. RESULTS: Based on this process, 10 recommendations were generated instead of the initial 9. As in the original publication, a graphical presentation with symbols was constructed to complement the written text. CONCLUSION: The ÖGR recommendations on nutrition and lifestyle for patients with gout and hyperuricemia were updated in accordance with the most recent relevant literature. These are supposed to serve as information and education material for patients and updated information for physicians.


Assuntos
Gota , Hiperuricemia , Reumatologia , Humanos , Hiperuricemia/diagnóstico , Hiperuricemia/tratamento farmacológico , Áustria , Gota/terapia , Estilo de Vida
2.
Acta Radiol Open ; 11(9): 20584601221128405, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-36157917

RESUMO

Background: Imaging of the portal vein prior to puncture for TIPS is essential. Purpose: With this study, we examined a modified retrograde portography with regard to the reliable representation of the portal vein. Material and Methods: Prospective evaluation of 65 TIPS interventions with regard to the delimitation of the portal vein and the exact parameters of retrograde portography such as catheter diameter and contrast medium volume per injection. Results: Retrograde portographies with a large-lumen catheter (10 F) and a large contrast medium volume (40 mL) were performed in 35/63 patients with significantly better delineation of the portal vein than when using 5 F catheters with 10 mL contrast medium. Conclusion: The so-called high volume retrograde portography leads to better delimitation of the portal vein during TIPS application.

3.
Int J Cosmet Sci ; 42(1): 68-78, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31630422

RESUMO

OBJECTIVE: In vitro assays were designed to examine the release of active Caspase-1 (ACasp-1) from NLRP inflammasome-activated Normal Human Epidermal Keratinocytes (NHEK) employing a bioluminescent assay specific for measuring inflammasome-induced ACasp-1 expression. METHODS: Four anticipated exogenous activators of the NLRP inflammasome including: UVB, ATP, Nigericin and Urban Dust were examined. Follow-up studies examined the influence of extracellular application of three different natural blends of known anti-inflammatories, one a polysaccharide blend and the other two antioxidant blends, one oil-soluble the other water-soluble, to examine ACasp-1 inhibition. Clinical work using the same blend of polysaccharides employed at 3% in a moisturizing formulation was examined for skin barrier recovery, measured with TEWL over a 60-h time frame after tape stripping on 10 individuals, and extended moisturization, measured using corneometer conductance after a single product application out through a 48-h regression on 10 individuals. RESULTS: In vitro results indicated that two exogenous activators, 60 mJ cm-2 UVB and 5 mM ATP, worked to upregulate expression of ACasp-1 within a 20-h timeframe. Additional studies were conducted to examine the influence of three extracellularly applied active ingredient blends. A blend of polysaccharides demonstrated potential to inhibit ACasp-1 expression in both UVB- and ATP-activated skin cells. Oil-soluble and water-soluble antioxidant blends inhibited ACasp-1 expression in UVB-activated keratinocytes but not ATP-activated keratinocytes. Barrier disruption studies indicated that 3% of the polysaccharide blend accelerated barrier recovery in a 60-h time frame as measured by TEWL. Skin hydration studies showed an ability for the polysaccharide blend to show significant improvements in skin hydration out to 48 h after a single application vs. a moisturizing placebo. CONCLUSIONS: The role of the skin's innate immune response, controlled by NLRP inflammasomes, is beginning to be linked to numerous skin conditions including inflammaging. In this work, it was found that: (i) an in vitro assay could activate NHEKs to express NLRP inflammasome-induced ACasp-1 expression, (ii) Ingredient blends inhibited UVB and ATP-induced NLRP inflammasome-induced ACasp-1 expression, and (iii) skin barrier disruption improvements and extended skin hydration could be achieved with 3% of the polysaccharide blend.


OBJECTIF: des dosages in vitro ont été conçus afin d'examiner la libération de caspase-1 (ACasp-1) active, à partir de kératinocytes épidermiques humains normaux (Normal Human Epidermal Keratinocytes, NHEK) activés via l'inflammasome NLRP, en utilisant un dosage par bioluminescence spécifique mesurant l'expression de l'ACasp-1 induite par l'inflammasome. MÉTHODES: quatre activateurs exogènes présumés de l'inflammasome NLRP : UVB, ATP, nigéricine et poussière urbaine, ont été examinés. Des études de suivi ont examiné l'influence de l'application extracellulaire de trois différents mélanges naturels d'anti-inflammatoires connus, l'un étant un mélange de polysaccharides et les deux autres des mélanges d'antioxydants, l'un soluble dans l'huile et l'autre dans l'eau, pour analyser l'inhibition de l'ACasp-1. Une étude clinique utilisant le même mélange de polysaccharides à 3 % dans une formulation hydratante, a analysé la récupération de la barrière cutanée, mesurée par la perte d'eau transépidermique (Trans Epidermal Water Loss, TEWL) sur une période de 60 h après prélèvement au moyen de ruban adhésif sur 10 personnes, ainsi que l'étendue de l'hydratation, par la mesure de la conductance à l'aide d'un cornéomètre après une seule application du produit au moyen d'une régression de 48 h, sur 10 personnes également. RÉSULTATS: les résultats in vitro ont indiqué que deux des activateurs exogènes, les UVB à 60 mJ/cm−2 et l'ATP à 5 mM, régulaient positivement l'expression de l'ACasp-1 sur une période de 20 h. D'autres études ont été menées pour examiner l'influence de trois mélanges de principes actifs appliqués de manière extracellulaire. Un mélange de polysaccharides a démontré un potentiel d'inhibition de l'expression de l'ACasp 1 dans les cellules cutanées activées par les UVB et par l'ATP. Les mélanges antioxydants solubles dans l'huile et dans l'eau ont inhibé l'expression de l'ACasp-1 dans les kératinocytes activés par les UVB mais pas dans les kératinocytes activés par l'ATP. Les études sur la perturbation de la barrière cutanée ont indiqué que le mélange de polysaccharide à 3 % accélérait la récupération de la barrière cutanée, dans un délai de 60 h telle que mesurée par le TEWL. Des études sur l'hydratation de la peau ont mis en évidence la capacité du mélange de polysaccharides à améliorer de manière significative l'hydratation de la peau jusqu'à 48 h après une seule application par rapport à un placebo de produit hydratant. CONCLUSIONS: le rôle de la réponse immunitaire innée de la peau, qui est contrôlée par les inflammasomes NLRP, commence à être associé à de nombreuses pathologies cutanées dont le phénomène inflammatoire. Il a été constaté, dans ce travail, que: (i) un dosage in vitro pouvait activer les NHEK permettant l'expression de l'ACasp-1 induite par l'inflammasome NLRP, (ii) les mélanges d'ingrédients inhibaient l'expression de l'ACasp-1 induite par les UVB et l'ATP via l'inflammasome NLRP, et (iii) des améliorations de la perturbation de la barrière cutanée ainsi qu'une hydratation prolongée de la peau pouvaient être obtenues avec un mélange de polysaccharides à 3%.


Assuntos
Dermatite/etiologia , Inflamassomos/metabolismo , Pele/patologia , Água/metabolismo , Adulto , Células Cultivadas , Feminino , Humanos , Masculino , Pessoa de Meia-Idade
4.
J R Soc Interface ; 15(148)2018 11 14.
Artigo em Inglês | MEDLINE | ID: mdl-30429265

RESUMO

Biological systems are dynamical, constantly exchanging energy and matter with the environment in order to maintain the non-equilibrium state synonymous with living. Developments in observational techniques have allowed us to study biological dynamics on increasingly small scales. Such studies have revealed evidence of quantum mechanical effects, which cannot be accounted for by classical physics, in a range of biological processes. Quantum biology is the study of such processes, and here we provide an outline of the current state of the field, as well as insights into future directions.


Assuntos
Biofísica/tendências , Biologia de Sistemas/tendências , Teoria Quântica
5.
AJR Am J Roentgenol ; 210(6): 1323-1329, 2018 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-29702022

RESUMO

OBJECTIVE: The purpose of this study was to compare findings of ultrasound (US) with dual-energy CT (DECT) findings in patients presenting with suspected gouty knee arthritis. SUBJECTS AND METHODS: This prospective study included 65 patients (52 men and 13 women; median age, 61.7 years [range, 38-87 years]) with an initial clinical diagnosis of acute gouty knee arthritis who underwent DECT performed using a 128-MDCT scanner and US performed using a 5-18-MHz transducer. Both intra- and extraarticular findings obtained using each modality were tabulated. RESULTS: DECT identified gout as the final diagnosis for 52 of 65 patients (80.0%). An alternative diagnosis was confirmed for the remaining 13 patients. US detected gout in 31 of 52 patients (sensitivity, 59.6%) and produced findings negative for gout in seven of 13 patients (specificity, 53.8%). The double contour sign on US was positive for gout in 23 of 52 patients (44.2%) and negative in 12 of 13 patients (92.3%). Extraarticular urate deposition was identified by DECT in 44 of 52 patients, compared with identification by US in 11 of 52 patients (p < 0.001). CONCLUSION: The sensitivity of US for the diagnosis of gouty knee arthritis is limited, particularly with respect to extraarticular urate deposition. The double contour sign is the single most valuable sign for the assessment of gouty knee arthritis by US.


Assuntos
Artrite Gotosa/diagnóstico por imagem , Articulação do Joelho/diagnóstico por imagem , Tomografia Computadorizada por Raios X/métodos , Ultrassonografia/métodos , Doença Aguda , Adulto , Idoso , Idoso de 80 Anos ou mais , Diagnóstico Diferencial , Feminino , Humanos , Imageamento Tridimensional , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Sensibilidade e Especificidade
6.
Epidemiol Infect ; 146(6): 698-704, 2018 04.
Artigo em Inglês | MEDLINE | ID: mdl-29564996

RESUMO

Delays in rotavirus vaccine schedule could improve performance in low- and middle-income countries (LMICs). However, delaying the first dose could be detrimental if infants experience severe rotavirus gastroenteritis (RVGE) early in life. Our objective was to describe the timing and predictors of severe RVGE in unvaccinated children in LMICs. We analysed the placebo arms from two clinical trials (cohort 1: NCT00241644; cohort 2: NCT00362648). We estimated the rate, cumulative incidence (per 1000 infants) and age distribution of severe RVGE episodes. Cox proportional hazards models were used to estimate hazard ratios and 95% confidence intervals (CI) for the association between baseline factors and severe RVGE. Cumulative incidence at 6 months of age was 23/1000 (95% CI 15-30) in cohort 1 and 6/1000 (95% CI 3-8) in cohort 2. Early antibiotic use (compared with no use) was associated with 2.03 (95% CI 1.18-3.48) and 1.41 (95% CI 0.80-2.51) times the rate of severe RVGE in cohorts 1 and 2, respectively. The cumulative incidence of severe RVGE was low at 6 months of age, suggesting that a 4-week delay in the vaccination schedule may not result in a large number of severe RVGE episodes prior to vaccine receipt.


Assuntos
Países em Desenvolvimento , Gastroenterite/epidemiologia , Infecções por Rotavirus/epidemiologia , Fatores Etários , Pré-Escolar , Ensaios Clínicos como Assunto , Feminino , Humanos , Incidência , Lactente , Masculino , Medição de Risco , Fatores de Risco , Vacinas contra Rotavirus/administração & dosagem
7.
J Phys Chem Lett ; 9(6): 1365-1371, 2018 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-29504765

RESUMO

Solar energy captured by pigments embedded in light-harvesting complexes can be transferred to neighboring pigments, dissipated, or emitted as fluorescence. Only when it reaches a reaction center is the excitation energy stabilized in the form of a charge separation and converted into chemical energy. Well-directed and regulated energy transfer within the network of pigments is therefore of crucial importance for the success of the photosynthetic processes. Using single-molecule spectroscopy, we show that phycocyanin can dynamically switch between two spectrally distinct states originating from two different conformations. Unexpectedly, one of the two states has a red-shifted emission spectrum. This state is not involved in energy dissipation; instead, we propose that it is involved in direct energy transfer to photosystem I. Finally, our findings suggest that the function of linker proteins in phycobilisomes is to stabilize one state or the other, thus controlling the light-harvesting functions of phycocyanin.

8.
J Evol Biol ; 31(2): 267-276, 2018 02.
Artigo em Inglês | MEDLINE | ID: mdl-29194826

RESUMO

Females are predicted to alter sex allocation when ecological, physiological and behavioural variables have different consequences on the fitness of male and female offspring. Traditionally, tests of sex allocation have examined single causative factors, often ignoring possible interactions between multiple factors. Here, we used a multifactorial approach to examine sex allocation in the viviparous skink, Niveoscincus ocellatus. We integrated a 16-year observational field study with a manipulative laboratory experiment to explore whether the effects of the maternal thermal environment interact with the resources available to females for reproduction to affect sex allocation decisions. We found strong effects of temperature on sex allocation in the field, with females born in warm conditions and males in cold conditions; however, this was not replicated in the laboratory. In contrast, we found no effect of female resource availability on sex allocation, either independently, or in interaction with temperature. These results corresponded with an overall lack of an effect of resource availability on any of the life history traits that we predicted would mediate the benefits of differential sex allocation in this system, suggesting that selection for sex allocation in response to resource availability may be relatively weak. Combined, these results suggest that temperature may be the predominant factor driving sex allocation in this system.


Assuntos
Lagartos/fisiologia , Reprodução , Processos de Determinação Sexual , Razão de Masculinidade , Animais , Feminino , Alimentos , Luz , Masculino , Temperatura , Viviparidade não Mamífera
9.
Psychol Med ; 48(2): 249-260, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-28625231

RESUMO

BACKGROUND: Sleep disturbances are prominent correlates of acute mood episodes and inadequate recovery in bipolar disorder (BD), yet the mechanistic relationship between sleep physiology and mood remains poorly understood. Using a series of pre-sleep mood inductions and overnight sleep recording, this study examined the relationship between overnight mood regulation and a marker of sleep intensity (non-rapid eye movement sleep slow wave activity; NREM SWA) during the interepisode phase of BD. METHODS: Adults with interepisode BD type 1 (BD; n = 20) and healthy adult controls (CTL; n = 23) slept in the laboratory for a screening night, a neutral mood induction night (baseline), a happy mood induction night, and a sad mood induction night. NREM SWA (0.75-4.75 Hz) was derived from overnight sleep EEG recordings. Overnight mood regulation was evaluated using an affect grid pleasantness rating post-mood induction (pre-sleep) and the next morning. RESULTS: Overnight mood regulation did not differ between groups following the sad or happy inductions. SWA did not significantly change for either group on the sad induction night compared with baseline. In BD only, SWA on the sad night was related to impaired overnight negative mood regulation. On the happy induction night, SWA increased relative to baseline in both groups, though SWA was not related to overnight mood regulation for either group. CONCLUSIONS: These findings indicate that SWA disruption may play a role in sustaining negative mood state from the previous night in interepisode BD. However, positive mood state could enhance SWA in bipolar patients and healthy adults.


Assuntos
Afeto/fisiologia , Transtorno Bipolar/fisiopatologia , Ondas Encefálicas/fisiologia , Polissonografia/métodos , Fases do Sono/fisiologia , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Autocontrole , Adulto Jovem
10.
J Appl Phys ; 121(19): 195301, 2017 May 21.
Artigo em Inglês | MEDLINE | ID: mdl-28611488

RESUMO

We investigate the formation of extended defects during molecular-dynamics (MD) simulations of GaN and InGaN growth on (0001) and ([Formula: see text]) wurtzite-GaN surfaces. The simulated growths are conducted on an atypically large scale by sequentially injecting nearly a million individual vapor-phase atoms towards a fixed GaN surface; we apply time-and-position-dependent boundary constraints that vary the ensemble treatments of the vapor-phase, the near-surface solid-phase, and the bulk-like regions of the growing layer. The simulations employ newly optimized Stillinger-Weber In-Ga-N-system potentials, wherein multiple binary and ternary structures are included in the underlying density-functional-theory training sets, allowing improved treatment of In-Ga-related atomic interactions. To examine the effect of growth conditions, we study a matrix of >30 different MD-growth simulations for a range of In x Ga 1-x N-alloy compositions (0 ≤ x ≤ 0.4) and homologous growth temperatures [0.50 ≤ T/T*m (x) ≤ 0.90], where T*m (x) is the simulated melting point. Growths conducted on polar (0001) GaN substrates exhibit the formation of various extended defects including stacking faults/polymorphism, associated domain boundaries, surface roughness, dislocations, and voids. In contrast, selected growths conducted on semi-polar ([Formula: see text]) GaN, where the wurtzite-phase stacking sequence is revealed at the surface, exhibit the formation of far fewer stacking faults. We discuss variations in the defect formation with the MD growth conditions, and we compare the resulting simulated films to existing experimental observations in InGaN/GaN. While the palette of defects observed by MD closely resembles those observed in the past experiments, further work is needed to achieve truly predictive large-scale simulations of InGaN/GaN crystal growth using MD methodologies.

12.
Phys Chem Chem Phys ; 18(37): 25852-60, 2016 Oct 07.
Artigo em Inglês | MEDLINE | ID: mdl-27604572

RESUMO

Photosystem II (PSII) is a huge pigment-protein supercomplex responsible for the primary steps of photosynthesis in green plants. Its light-harvesting antenna exhibits efficient transfer of the absorbed excitation energy to the reaction center and also contains a well-regulated protection mechanism against over-excitation in strong light conditions. The latter is based on conformational changes in antenna complexes that open up excitation decay channels resulting in considerable fluorescence quenching. Meanwhile, fluorescence blinking, observed in single antennas, is likely caused by a similar mechanism. Thus the question arises whether this effect is also present in and relevant to the native supramolecular organization of a fully assembled PSII. To further investigate energy transfer and quenching in single PSII, we performed single-molecule experiments on PSII supercomplexes at 5 °C. Analysis of the fluorescence intensity and mean lifetime allowed us to distinguish detached antennas and specifically analyze PSII supercomplexes. The average fluorescence lifetime in PSII of about 100-150 ps, measured under our extreme excitation conditions, is surprisingly similar to published ensemble lifetime data of photochemical quenching in PSII of a similar size. In our case, this lifetime is nevertheless caused by either one or multiple quenched antennas or by a quencher in the reaction center. The observed reversible light-induced changes in fluorescence intensity on a millisecond timescale are reminiscent of blinking subunits. Our results therefore directly illustrate how environmental control over a fluctuating antenna can regulate light-harvesting in plant photosynthesis.


Assuntos
Complexos de Proteínas Captadores de Luz/química , Complexo de Proteína do Fotossistema II/química , Clorofila/química , Transferência de Energia , Fluorescência , Cinética , Simulação de Dinâmica Molecular , Fotossíntese , Conformação Proteica , Multimerização Proteica , Imagem Individual de Molécula
13.
J Biol Chem ; 291(32): 16730-9, 2016 08 05.
Artigo em Inglês | MEDLINE | ID: mdl-27252376

RESUMO

The light reactions of photosynthesis, which include light-harvesting and charge separation, take place in the amphiphilic environment of the thylakoid membrane. The light-harvesting complex II (LHCII) is the main responsible for light absorption in plants and green algae and is involved in photoprotective mechanisms that regulate the amount of excited states in the membrane. The dual function of LHCII has been extensively studied in detergent micelles, but recent results have indicated that the properties of this complex differ in a lipid environment. In this work we checked these suggestions by studying LHCII in liposomes. By combining bulk and single molecule measurements, we monitored the fluorescence characteristics of liposomes containing single complexes up to densely packed proteoliposomes. We show that the natural lipid environment per se does not alter the properties of LHCII, which for single complexes remain very similar to that in detergent. However, we show that LHCII has the strong tendency to cluster in the membrane and that protein interactions and the extent of crowding modulate the lifetimes of the excited state in the membrane. Finally, the presence of LHCII monomers at low concentrations of complexes per liposome is discussed.


Assuntos
Membrana Celular/metabolismo , Chlamydomonas reinhardtii/metabolismo , Complexos de Proteínas Captadores de Luz/metabolismo , Lipídeos de Membrana/metabolismo , Membrana Celular/química , Chlamydomonas reinhardtii/química , Complexos de Proteínas Captadores de Luz/química , Lipídeos de Membrana/química
14.
Sci Rep ; 6: 26230, 2016 05 18.
Artigo em Inglês | MEDLINE | ID: mdl-27189196

RESUMO

We derive approximate equations of motion for excited state dynamics of a multilevel open quantum system weakly interacting with light to describe fluorescence-detected single molecule spectra. Based on the Frenkel exciton theory, we construct a model for the chlorophyll part of the LHCII complex of higher plants and its interaction with previously proposed excitation quencher in the form of the lutein molecule Lut 1. The resulting description is valid over a broad range of timescales relevant for single molecule spectroscopy, i.e. from ps to minutes. Validity of these equations is demonstrated by comparing simulations of ensemble and single-molecule spectra of monomeric LHCII with experiments. Using a conformational change of the LHCII protein as a switching mechanism, the intensity and spectral time traces of individual LHCII complexes are simulated, and the experimental statistical distributions are reproduced. Based on our model, it is shown that with reasonable assumptions about its interaction with chlorophylls, Lut 1 can act as an efficient fluorescence quencher in LHCII.

15.
Proc Natl Acad Sci U S A ; 113(11): 2934-9, 2016 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-26903650

RESUMO

Energy relaxation in light-harvesting complexes has been extensively studied by various ultrafast spectroscopic techniques, the fastest processes being in the sub-100-fs range. At the same time, much slower dynamics have been observed in individual complexes by single-molecule fluorescence spectroscopy (SMS). In this work, we use a pump-probe-type SMS technique to observe the ultrafast energy relaxation in single light-harvesting complexes LH2 of purple bacteria. After excitation at 800 nm, the measured relaxation time distribution of multiple complexes has a peak at 95 fs and is asymmetric, with a tail at slower relaxation times. When tuning the excitation wavelength, the distribution changes in both its shape and position. The observed behavior agrees with what is to be expected from the LH2 excited states structure. As we show by a Redfield theory calculation of the relaxation times, the distribution shape corresponds to the expected effect of Gaussian disorder of the pigment transition energies. By repeatedly measuring few individual complexes for minutes, we find that complexes sample the relaxation time distribution on a timescale of seconds. Furthermore, by comparing the distribution from a single long-lived complex with the whole ensemble, we demonstrate that, regarding the relaxation times, the ensemble can be considered ergodic. Our findings thus agree with the commonly used notion of an ensemble of identical LH2 complexes experiencing slow random fluctuations.


Assuntos
Transferência de Energia , Complexos de Proteínas Captadores de Luz/química , Espectrometria de Fluorescência/métodos , Bacterioclorofilas/química , Bacterioclorofilas/efeitos da radiação , Lasers , Luz , Complexos de Proteínas Captadores de Luz/efeitos da radiação , Microscopia Confocal , Distribuição Normal , Rodopseudomonas/química , Estatísticas não Paramétricas , Tempo
16.
Phys Chem Chem Phys ; 17(30): 19844-53, 2015 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-26156159

RESUMO

In light harvesting complex II (LHCII) of higher plants and green algae, carotenoids (Cars) have an important function to quench chlorophyll (Chl) triplet states and therefore avoid the production of harmful singlet oxygen. The resulting Car triplet states lead to a non-linear self-quenching mechanism called singlet-triplet (S-T) annihilation that strongly depends on the excitation density. In this work we investigated the fluorescence decay kinetics of single immobilized LHCIIs at room temperature and found a two-exponential decay with a slow (3.5 ns) and a fast (35 ps) component. The relative amplitude fraction of the fast component increases with increasing excitation intensity, and the resulting decrease in the fluorescence quantum yield suggests annihilation effects. Modulation of the excitation pattern by means of an acousto-optic modulator (AOM) furthermore allowed us to resolve the time-dependent accumulation and decay rate (∼7 µs) of the quenching species. Inspired by singlet-singlet (S-S) annihilation studies, we developed a stochastic model and then successfully applied it to describe and explain all the experimentally observed steady-state and time-dependent kinetics. That allowed us to distinctively identify the quenching mechanism as S-T annihilation. Quantitative fitting resulted in a conclusive set of parameters validating our interpretation of the experimental results. The obtained stochastic model can be generalized to describe S-T annihilation in small molecular aggregates where the equilibration time of excitations is much faster than the annihilation-free singlet excited state lifetime.


Assuntos
Complexos de Proteínas Captadores de Luz/química , Clorofila/química , Cinética , Complexos de Proteínas Captadores de Luz/metabolismo , Modelos Teóricos , Teoria Quântica , Espectrometria de Fluorescência
17.
Z Rheumatol ; 74(7): 631-6, 2015 Sep.
Artigo em Alemão | MEDLINE | ID: mdl-26014619

RESUMO

BACKGROUND: Gout is the most common inflammatory arthropathy in the Western world. This is mainly due to the high socioeconomic status, sufficient even superfluous nutrition, overweight and alcohol consumption. Despite adequate medication, information and advice on nutrition and lifestyle are one of the cornerstones in the management of these patients. OBJECTIVE: The aim was to provide recommendations on nutrition and lifestyle in cases of gout and hyperuricemia by a group of rheumatologists, based on a review of the most recent literature. MATERIALS AND METHODS: The study group for osteoarthritis and crystal arthropathies of the Austrian Society for Rheumatology and Rehabilitation (ÖGR) carried out a literature search on this topic. The selected papers were listed according to the level of evidence. RESULTS: Based on this literature search nine recommendations were generated and modified via a Delphi approach: four red "don'ts" concerning nutrition and beverages to be avoided, three green "do's" concerning favorable food as well as two blue general lifestyle recommendations. The format of the recommendations is a two-page leaflet with the list of recommendations, level of evidence, strength of recommendation and literature citations on the front page and a colored icon presentation of food and beverages in a circle, matching the colors of the written recommendations, on the reverse. CONCLUSION: For the first time in Austria, nine recommendations on nutrition, beverages and lifestyle for patients with gout and hyperuricemia were defined for everyday practice, as education material for patients and updated information for physicians.


Assuntos
Dietoterapia/normas , Gota/terapia , Hiperuricemia/terapia , Política Nutricional , Reumatologia/normas , Comportamento de Redução do Risco , Áustria , Humanos , Guias de Prática Clínica como Assunto
18.
Biophys J ; 108(5): 1047-56, 2015 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-25762317

RESUMO

In the major peripheral plant light-harvesting complex LHCII, excitation energy is transferred between chlorophylls along an energetic cascade before it is transmitted further into the photosynthetic assembly to be converted into chemical energy. The efficiency of these energy transfer processes involves a complicated interplay of pigment-protein structural reorganization and protein dynamic disorder, and the system must stay robust within the fluctuating protein environment. The final, lowest energy site has been proposed to exist within a trimeric excitonically coupled chlorophyll (Chl) cluster, comprising Chls a610-a611-a612. We studied an LHCII monomer with a site-specific mutation resulting in the loss of Chls a611and a612, and find that this mutant exhibits two predominant overlapping fluorescence bands. From a combination of bulk measurements, single-molecule fluorescence characterization, and modeling, we propose the two fluorescence bands originate from differing conditions of exciton delocalization and localization realized in the mutant. Disruption of the excitonically coupled terminal emitter Chl trimer results in an increased sensitivity of the excited state energy landscape to the disorder induced by the protein conformations. Consequently, the mutant demonstrates a loss of energy transfer efficiency. On the contrary, in the wild-type complex, the strong resonance coupling and correspondingly high degree of excitation delocalization within the Chls a610-a611-a612 cluster dampens the influence of the environment and ensures optimal communication with neighboring pigments. These results indicate that the terminal emitter trimer is thus an essential design principle for maintaining the efficient light-harvesting function of LHCII in the presence of protein disorder.


Assuntos
Proteínas de Arabidopsis/metabolismo , Complexos de Proteínas Captadores de Luz/metabolismo , Arabidopsis/metabolismo , Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Fluorescência , Complexos de Proteínas Captadores de Luz/química , Complexos de Proteínas Captadores de Luz/genética , Mutação , Multimerização Proteica
19.
Case Rep Hematol ; 2015: 201536, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25789184

RESUMO

Langerhans cell histiocytosis (LCH) is a rare myeloid neoplasm characterized by the proliferation and dissemination of histiocytes. These in turn may cause symptoms ranging from isolated, infiltrative lesions to severe multisystem disease. Pulmonary Langerhans cell histiocytosis (PLCH) presents as a localized polyclonal proliferation of Langerhans cells in the lungs causing bilateral cysts and fibrosis. In adults, this rare condition is considered a reactive process associated with cigarette smoking. Recently, clonal proliferation has been reported with the presence of BRAF V600E oncogenic mutation in a subset of PLCH patients. Spontaneous resolution was described; however, based on case series, smoking cessation remains the most effective way to achieve complete remission and prevent long term complications related to tobacco. Herein, we report the case of an adult woman with biopsy-proven PLCH presenting with thoracic (T8) vertebral bone destruction. Both the lung and the bone diseases regressed following smoking cessation, representing a rare case of synchronous disseminated PCLH with bone localization. This observation underscores the contribution of cigarette smoking as a systemic trigger of both pulmonary and extrapulmonary bone lesions. A review of similar cases in the literature is also presented.

20.
Psychol Med ; 45(8): 1751-63, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25515854

RESUMO

BACKGROUND: Though poorly defined, hypersomnia is associated with negative health outcomes and new-onset and recurrence of psychiatric illness. Lack of definition impedes generalizability across studies. The present research clarifies hypersomnia diagnoses in bipolar disorder by exploring possible subgroups and their relationship to prospective sleep data and relapse into mood episodes. METHOD: A community sample of 159 adults (aged 18-70 years) with bipolar spectrum diagnoses, euthymic at study entry, was included. Self-report inventories and clinician-administered interviews determined features of hypersomnia. Participants completed sleep diaries and wore wrist actigraphs at home to obtain prospective sleep data. Approximately 7 months later, psychiatric status was reassessed. Factor analysis and latent profile analysis explored empirical groupings within hypersomnia diagnoses. RESULTS: Factor analyses confirmed two separate subtypes of hypersomnia ('long sleep' and 'excessive sleepiness') that were uncorrelated. Latent profile analyses suggested a four-class solution, with 'long sleep' and 'excessive sleepiness' again representing two separate classes. Prospective sleep data suggested that the sleep of 'long sleepers' is characterized by a long time in bed, not long sleep duration. Longitudinal assessment suggested that 'excessive sleepiness' at baseline predicted mania/hypomania relapse. CONCLUSIONS: This study is the largest of hypersomnia to include objective sleep measurement, and refines our understanding of classification, characterization and associated morbidity. Hypersomnia appears to be comprised of two separate subgroups: long sleep and excessive sleepiness. Long sleep is characterized primarily by long bedrest duration. Excessive sleepiness is not associated with longer sleep or bedrest, but predicts relapse to mania/hypomania. Understanding these entities has important research and treatment implications.


Assuntos
Transtorno Bipolar/complicações , Transtorno Bipolar/psicologia , Distúrbios do Sono por Sonolência Excessiva/complicações , Distúrbios do Sono por Sonolência Excessiva/psicologia , Actigrafia , Adolescente , Adulto , Idoso , Análise Fatorial , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Recidiva , Sono , Adulto Jovem
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