Improving benefit-harm assessment of glucocorticoid therapy incorporating the patient perspective: The OMERACT glucocorticoid core domain set.

OBJECTIVE: Our primary objective was to develop an Outcome Measures in Rheumatology (OMERACT) core domain set to capture the impact of glucocorticoids (GC), both positive and negative, on patients with Rheumatic conditions. METHODS: The OMERACT Filter 2.1 was used to guide core domain selection. Systematic literature reviews, qualitative studies and quantitative surveys were conducted by the OMERACT GC Impact working group to identify candidate domains for a core domain set. A summary of prior work and Delphi exercise were presented at the OMERACT 2020 virtual GC workshop. A proposed GC Impact core domain set derived from this work was presented for discussion in facilitated breakout groups. Participants voted on the proposed GC Impact core domain set. RESULTS: 113 people, including 23 patient research partners, participated in two virtual workshops conducted at different times on the same day. The proposed mandatory domains to be evaluated in clinical trials involving GCs were: infection, bone fragility, hypertension, diabetes, weight, fatigue, mood disturbance and death. In addition, collection of disease specific outcomes was included in the core domain set as "mandatory in specific circumstances". The proposed core domain set was endorsed by 100% (23/23) of the patient research partners and 92% (83/90) of the remaining participants, including clinicians, researchers and industry stakeholders. CONCLUSION: A GC Impact core domain set was endorsed at the OMERACT 2020 virtual workshop. The OMERACT GC Impact working group will now progress to identify, develop and validate measurement tools to best address these domains in clinical trials.

Body Fat Assessment in International Elite Soccer Referees.

Soccer referees are a specific group in the sports population that are receiving increasing attention from sports scientists. A lower fat mass percentage (FM%) is a useful parameter to monitor fitness status and aerobic performance, while being able to evaluate it with a simple and quick field-based method can allow a regular assessment. The aim of this study was to provide a specific profile for referees based on morphological and body composition features while comparing the accuracy of different skinfold-based equations in estimating FM% in a cohort of soccer referees. Forty-three elite international soccer referees (age 38.8 ± 3.6 years), who participated in the 2018 Russian World Cup, underwent body composition assessments with skinfold thickness and dual-energy X-ray absorptiometry (DXA). Six equations used to derive FM% from skinfold thickness were compared with DXA measurements. The percentage of body fat estimated using DXA was 18.2 ± 4.1%, whereas skinfold-based FM% assessed from the six formulas ranged between 11.0% ± 1.7% to 15.6% ± 2.4%. Among the six equations considered, the Faulkner's formula showed the highest correlation with FM% estimated by DXA (r = 0.77; R2 = 0.59 p < 0.001). Additionally, a new skinfold-based equation was developed: FM% = 8.386 + (0.478 × iliac crest skinfold) + (0.395 × abdominal skinfold, r = 0.78; R2 = 0.61; standard error of the estimate (SEE) = 2.62 %; p < 0.001). Due to these findings, national and international federations will now be able to perform regular body composition assessments using skinfold measurements.

The role of electrostatics in TrxR electron transfer mechanism: A computational approach.

Thioredoxin reductase (TrxR) is an important enzyme in the control of the intracellular reduced redox environment. It transfers electrons from NADPH to several molecules, including its natural partner, thioredoxin. Although there is a generally accepted model describing how the electrons are transferred along TrxR, which involves a flexible arm working as a "shuttle," the molecular details of such mechanism are not completely understood. In this work, we use molecular dynamics simulations with Poisson-Boltzmann/Monte Carlo pKa calculations to investigate the role of electrostatics in the electron transfer mechanism. We observed that the combination of redox/protonation states of the N-terminal (FAD and Cys59/64) and C-terminal (Cys497/Selenocysteine498) redox centers defines the preferred relative positions and allows for the flexible arm to work as the desired "shuttle." Changing the redox/ionization states of those key players, leads to electrostatic triggers pushing the arm into the pocket when oxidized, and pulling it out, once it has been reduced. The calculated pKa values for Cys497 and Selenocysteine498 are 9.7 and 5.8, respectively, confirming that the selenocysteine is indeed deprotonated at physiological pH. This can be an important advantage in terms of reactivity (thiolate/selenolate are more nucleophilic than thiol/selenol) and ability to work as an electrostatic trigger (the "shuttle" mechanism) and may be the reason why TrxR uses selenium instead of sulfur. Proteins 2016; 84:1836-1843. © 2016 Wiley Periodicals, Inc.

Association between energy density and diet cost in children.

HIGHLIGHTS: The average of the energy-adjusted diet cost in 6-12 years-old children was 2.17€/1000Kcal (SD + 0.49).Energy-density diets (EDs - Kcal/g) were calculated by three distinct methods: (1) with food and all beverages (ED1), (2) with food and caloric beverages (ED2), and (3) only with food (ED3).The distributions of the three EDs were statistically different, being higher the ED3 - calculated excluding all beverages (1.15Kcal (SD + 0.28) vs. ED2: 1.10Kcal/g; SD + 0.24 vs. ED1: 0.99Kcal/g; SD + 0.22).Lower energy-density diets (EDs) were associated with higher diet cost in a sample of school children from a Mediterranean country, regardless the differences between the EDs calculated by three distinct methods. BACKGROUND: Lower energy density diets tend to cost more, but data using different ways to calculate the dietary energy density, is scarce. OBJECTIVES: To estimate the dietary energy density, and to assess how it is associated with the diet cost in children. METHODS: Data were obtained from a community-based survey from public elementary schools in Portugal. Dietary intake of 464 children (6-12 years) was assessed by a 24 h recall in 2007/2008. Dietary energy density (kcal/g) was calculated as following: (1) with food and all beverages (ED1), (2) with food and caloric beverages (ED2), and (3) only with food (ED3). Energy-adjusted diet cost (€/1000 kcal) was calculated based on the collection of food prices from a national leader supermarket. Anthropometric measures were taken and socio-demographic data were obtained from parents. Logistic regression was used to estimate the association between diet cost and energy density. RESULTS: For boys, the energy-adjusted diet cost of the highest third of energy density was lower, between 81% in the ED3 (p for trend <0.001) and 87% in the ED1 (p for trend <0.001), compared to the lowest third. Girls showed similar, but weaker associations. CONCLUSIONS: Higher dietary energy density was associated with lower dietary cost among children.

Food patterns according to sociodemographics, physical activity, sleeping and obesity in Portuguese children.

Our study aimed to describe the association between food patterns and gender, parental education, physical activity, sleeping and obesity in 1976 children aged 5-10 years old. Dietary intake was measured by a semi quantitative food frequency questionnaire; body mass index was calculated and categorized according to the IOTF classification. Factor analysis and generalized linear models were applied to identify food patterns and their associations. TV viewing and male gender were significant positive predictors for fast-food, sugar sweetened beverages and pastry pattern, while a higher level of maternal education and longer sleeping duration were positively associated with a dietary patterns that included fruit and vegetables.

Proton pathways in a [NiFe]-hydrogenase: A theoretical study.

We present here a theoretical study to investigate possible proton pathways in the [NiFe]-hydrogenase from Desulfovibrio gigas. The approach used in this study consists of a combination of Poisson-Boltzmann and Monte Carlo simulations together with a distance-based network analysis to find possible groups involved in the proton transfer. Results obtained at different pH values show a reasonable number of proton active residues distributed by the protein interior and surface, with a concentration around the metal centres. The electrostatic interactions in this protein are strong, as shown by the unusual shape of the titration curves of several sites. Some residue pairs show strongly correlated protonations, indicating the sharing and probably exchange of a proton between them. The conjugation of the PB and MC simulations with the distance-based analysis allows a detailed characterization of the possible proton pathways. We discuss previous suggestions and propose a new complete pathway for the proton transfer between the active site and the surface. This pathway is mainly composed of histidines and glutamic acid residues.

Redox-Bohr and other cooperativity effects in the nine-heme cytochrome C from Desulfovibrio desulfuricans ATCC 27774: crystallographic and modeling studies.

The nine-heme cytochrome c is a monomeric multiheme cytochrome found in Desulfovibrio desulfuricans ATCC 27774. The polypeptide chain comprises 296 residues and wraps around nine hemes of type c. It is believed to take part in the periplasmic assembly of proteins involved in the mechanism of hydrogen cycling, receiving electrons from the tetraheme cytochrome c3. With the purpose of understanding the molecular basis of electron transfer processes in this cytochrome, we have determined the crystal structures of its oxidized and reduced forms at pH 7.5 and performed theoretical calculations of the binding equilibrium of protons and electrons in these structures. This integrated study allowed us to observe that the reduction process induced relevant conformational changes in several residues, as well as protonation changes in some protonatable residues. In particular, the surroundings of hemes I and IV constitute two areas of special interest. In addition, we were able to ascertain the groups involved in the redox-Bohr effect present in this cytochrome and the conformational changes that may underlie the redox-cooperativity effects on different hemes. Furthermore, the thermodynamic simulations provide evidence that the N- and C-terminal domains function in an independent manner, with the hemes belonging to the N-terminal domain showing, in general, a lower redox potential than those found in the C-terminal domain. In this way, electrons captured by the N-terminal domain could easily flow to the C-terminal domain, allowing the former to capture more electrons. A notable exception is heme IX, which has low redox potential and could serve as the exit path for electrons toward other proteins in the electron transfer pathway.

Studies of the reduction and protonation behavior of tetraheme cytochromes using atomic detail.

A comparative study of tetraheme cytochrome c3 molecules from several species was carried out using recently developed theoretical methods based on continuum electrostatics. The binding joint equilibrium of electrons and protons was simulated, revealing the complete thermodynamic aspects of electron-proton coupling in these molecules. The method yields excellent accuracy in terms of midpoint potentials, giving the correct reduction orders in all molecules examined, except for one heme site. The coupling between electrons and protons is shown to be present and significant at physiological pH in all cases. This phenomenon, known as the redox-Bohr effect, though of thermodynamic nature, is shown to have an intrinsic "dynamic" character at the molecular level (in the sense of the empty/occupied fluctuations at the microscopic level), with the binding states of redox and protonatable sites displaying both correlated averages and correlated fluctuations. The protonatable sites more directly involved in the redox-Bohr effect are identified using, among other properties, the statistical correlation between pairs of sites, which automatically reflects indirect effects mediated by other sites. Several sites are identified in this analysis. Propionate D of heme I seems to be the most interesting, generally showing a high correlation not only with its own heme, but also with heme II, corresponding to an indirect stabilization of the reduced forms of both hemes. Other interesting sites are the free histidines of two of the cytochromes and propionate D of heme IV, the latter being potentially associated with redox-induced structural changes. Among the set of cytochromes c3 analyzed in this study, significant differences are observed for several properties of the acidic cytochrome included in the set, from Desulfovibrio africanus, supporting the hypothesis of a different functional role.