Energetics of RecA-mediated recombination reactions. Without ATP hydrolysis RecA can mediate polar strand exchange but is unable to recycle.

We demonstrate that the step of DNA strand exchange during RecA-mediated recombination reaction can occur equally efficiently in the presence or absence of ATP hydrolysis. The polarity of strand exchange is the same when instead of ATP its non-hydrolyzable analog adenosine-5'-O-(3-thiotriphosphate) is used. We show that the ATP dependence of recombination reaction is limited to the post-exchange stages of the reactions. The low DNA affinity state of RecA protomers, induced after ATP hydrolysis, is necessary for the dissociation of RecA-DNA complexes at the end of the reaction. This dissociation of RecA from DNA is necessary for the release of recombinant DNA molecules from the complexes formed with RecA and for the recycling of RecA protomers for another round of the recombination reaction.

Protein interaction data curation: the International Molecular Exchange (IMEx) consortium.

The International Molecular Exchange (IMEx) consortium is an international collaboration between major public interaction data providers to share literature-curation efforts and make a nonredundant set of protein interactions available in a single search interface on a common website (http://www.imexconsortium.org/). Common curation rules have been developed, and a central registry is used to manage the selection of articles to enter into the dataset. We discuss the advantages of such a service to the user, our quality-control measures and our data-distribution practices.

Evolution of endurance during a multidisciplinary treatment of chronic low back pain and its influence of work capacity

Introduction: Low back pain is a common disorder touching up to 80% of the population, with redundancies of up to 70%. A small proportion would go on to develop chronic low back pain (LBP) with reduced work capacity and they would count for the majority of the costs. Up to day, a multi-disciplinary treatment program is one of the best approaches. In the program one of the mile-stones is restoration of function. The aim of this study was to follow patients, according to the endurance change after the program and its influence on workability during one year after inclusion in a such program. Method: Patients were following a multidisciplinary treatment for 3 weeks including physiotherapy, occupation measures combined with an educational program with behavioural and psychological interventions on an outpatient program. We studied the endurance with the help of the Bruce test, accomplished at the beginning and at the end of the program. On the other hand the patients filled out pain questionnaires and PACT score according their own impression on workability. Results: There were a clear relation between the increase in the cardiovascular endurance and the increased workability. Almost every patient presented an increase in the VO2 max, even though the workability did not follow. This increase were associated with a decrease in pain apprehension. Conclusion: A multidisciplinary treatment program, teaching the patients how to care with their pain and to accept it even if it persist is successful in lowering the global pain. If the program allows the patients to strengthen the endurance, the workability will increase in parallel. In this way the patients were able to reduce the consummation of medicaments and to increase the work capacity.

On problems of calculating energy expenditure and substrate utilization from respiratory exchange data.

Indirect calorimetry based on respiratory exchange measurement has been successfully used from the beginning of the century to obtain an estimate of heat production (energy expenditure) in human subjects and animals. The errors inherent to this classical technique can stem from various sources: 1) model of calculation and assumptions, 2) calorimetric factors used, 3) technical factors and 4) human factors. The physiological and biochemical factors influencing the interpretation of calorimetric data include a change in the size of the bicarbonate and urea pools and the accumulation or loss (via breath, urine or sweat) of intermediary metabolites (gluconeogenesis, ketogenesis). More recently, respiratory gas exchange data have been used to estimate substrate utilization rates in various physiological and metabolic situations (fasting, post-prandial state, etc.). It should be recalled that indirect calorimetry provides an index of overall substrate disappearance rates. This is incorrectly assumed to be equivalent to substrate "oxidation" rates. Unfortunately, there is no adequate golden standard to validate whole body substrate "oxidation" rates, and this contrasts to the "validation" of heat production by indirect calorimetry, through use of direct calorimetry under strict thermal equilibrium conditions. Tracer techniques using stable (or radioactive) isotopes, represent an independent way of assessing substrate utilization rates. When carbohydrate metabolism is measured with both techniques, indirect calorimetry generally provides consistent glucose "oxidation" rates as compared to isotopic tracers, but only when certain metabolic processes (such as gluconeogenesis and lipogenesis) are minimal or / and when the respiratory quotients are not at the extreme of the physiological range. However, it is believed that the tracer techniques underestimate true glucose "oxidation" rates due to the failure to account for glycogenolysis in the tissue storing glucose, since this escapes the systemic circulation. A major advantage of isotopic techniques is that they are able to estimate (given certain assumptions) various metabolic processes (such as gluconeogenesis) in a noninvasive way. Furthermore when, in addition to the 3 macronutrients, a fourth substrate is administered (such as ethanol), isotopic quantification of substrate "oxidation" allows one to eliminate the inherent assumptions made by indirect calorimetry. In conclusion, isotopic tracers techniques and indirect calorimetry should be considered as complementary techniques, in particular since the tracer techniques require the measurement of carbon dioxide production obtained by indirect calorimetry. However, it should be kept in mind that the assessment of substrate oxidation by indirect calorimetry may involve large errors in particular over a short period of time. By indirect calorimetry, energy expenditure (heat production) is calculated with substantially less error than substrate oxidation rates.

An exploratory study on facial emotion recognition capacity in beginning Alzheimer's disease.

Objective: It was the aim of this study to investigate facial emotion recognition (FER) in the elderly with cognitive impairment. Method: Twelve patients with Alzheimer's disease (AD) and 12 healthy control subjects were asked to name dynamic or static pictures of basic facial emotions using the Multimodal Emotion Recognition Test and to assess the degree of their difficulty in the recognition task, while their electrodermal conductance was registered as an unconscious processing measure. Results: AD patients had lower objective recognition performances for disgust and fear, but only disgust was accompanied by decreased subjective FER in AD patients. The electrodermal response was similar in all groups. No significant effect of dynamic versus static emotion presentation on FER was found. Conclusion: Selective impairment in recognizing facial expressions of disgust and fear may indicate a nonlinear decline in FER capacity with increasing cognitive impairment and result from progressive though specific damage to neural structures engaged in emotional processing and facial emotion identification. Although our results suggest unchanged unconscious FER processing with increasing cognitive impairment, further investigations on unconscious FER and self-awareness of FER capacity in neurodegenerative disorders are required.

Differences in the transduction of canonical wnt signals demarcate effector and memory CD8 T cells with distinct recall proliferation capacity.

Protection against reinfection is mediated by Ag-specific memory CD8 T cells, which display stem cell-like function. Because canonical Wnt (Wingless/Int1) signals critically regulate renewal versus differentiation of adult stem cells, we evaluated Wnt signal transduction in CD8 T cells during an immune response to acute infection with lymphocytic choriomeningitis virus. Whereas naive CD8 T cells efficiently transduced Wnt signals, at the peak of the primary response to infection only a fraction of effector T cells retained signal transduction and the majority displayed strongly reduced Wnt activity. Reduced Wnt signaling was in part due to the downregulation of Tcf-1, one of the nuclear effectors of the pathway, and coincided with progress toward terminal differentiation. However, the correlation between low and high Wnt levels with short-lived and memory precursor effector cells, respectively, was incomplete. Adoptive transfer studies showed that low and high Wnt signaling did not influence cell survival but that Wnt high effectors yielded memory cells with enhanced proliferative potential and stronger protective capacity. Likewise, following adoptive transfer and rechallenge, memory cells with high Wnt levels displayed increased recall expansion, compared with memory cells with low Wnt signaling, which were preferentially effector-like memory cells, including tissue-resident memory cells. Thus, canonical Wnt signaling identifies CD8 T cells with enhanced proliferative potential in part independent of commonly used cell surface markers to discriminate effector and memory T cell subpopulations. Interventions that maintain Wnt signaling may thus improve the formation of functional CD8 T cell memory during vaccination.

Respiratory muscle training enhances maximal minute ventilation and forced vital capacity in adolescent athletes.

Introduction. Respiratory difficulties in athletes are common, especially in adolescents, even in the absence of exercise-induced bronchoconstriction. Immaturity of the respiratory muscles coupling at high respiratory rates could be a potential mechanism. Whether respiratory muscle training (RMT) can positively influence it is yet unknown. Goal. We investigate the effects of RMT on ventilation and performance parameters in adolescent athletes and hypothesize that RMT will enhance respiratory capacity. Methods. 12 healthy subjects (8 male, 4 female, 17±0.5 years) from a sports/study high school class, competitively involved in various sports (minimum of 10 hours per week) underwent respiratory function testing, maximal minute ventilation (MMV) measurements and a maximal treadmill incremental test with VO2max and ventilatory thresholds (VT1 and VT2) determination. They then underwent one month of RMT (4 times/week) using a eucapnic hyperventilation device, with an incremental training program. The same tests were repeated after RMT. Results. Subjects completed 14.8 sessions of RMT, with an increase in total ventilation per session of 211±29% during training. Borg scale evaluation of the RMT session was unchanged or reduced in all subjects, despite an increase in total respiratory work. No changes (p>0.05) were observed pre/post RMT in VO2max (53.4±7.5 vs 51.6±7.7 ml/kg/min), VT2 (14.4±1.4 vs 14.0±1.1 km/h) or Speed max at end of test (16.1±1.7 vs 15.8±1.7 km/h). MVV increased by 9.2% (176.7±36.9 vs 192.9±32.6 l/min, p<0.001) and FVC by 3.3% (6.70±0.75 vs 4.85±0.76 litres, p<0.05). Subjective evaluation of respiratory sensations during exercise and daily living were also improved. Conclusions. RMT improves MMV and FVC in adolescent athletes, along with important subjective respiratory benefits, although no changes are seen in treadmill maximal performance tests and VO2max measurements. RMT can be easily performed in adolescent without side effects, with a potential for improvement in training capacity and overall well-being.

The mzTab Data Exchange Format: Communicating Mass-spectrometry-based Proteomics and Metabolomics Experimental Results to a Wider Audience.

The HUPO Proteomics Standards Initiative has developed several standardized data formats to facilitate data sharing in mass spectrometry (MS)-based proteomics. These allow researchers to report their complete results in a unified way. However, at present, there is no format to describe the final qualitative and quantitative results for proteomics and metabolomics experiments in a simple tabular format. Many downstream analysis use cases are only concerned with the final results of an experiment and require an easily accessible format, compatible with tools such as Microsoft Excel or R. We developed the mzTab file format for MS-based proteomics and metabolomics results to meet this need. mzTab is intended as a lightweight supplement to the existing standard XML-based file formats (mzML, mzIdentML, mzQuantML), providing a comprehensive summary, similar in concept to the supplemental material of a scientific publication. mzTab files can contain protein, peptide, and small molecule identifications together with experimental metadata and basic quantitative information. The format is not intended to store the complete experimental evidence but provides mechanisms to report results at different levels of detail. These range from a simple summary of the final results to a representation of the results including the experimental design. This format is ideally suited to make MS-based proteomics and metabolomics results available to a wider biological community outside the field of MS. Several software tools for proteomics and metabolomics have already adapted the format as an output format. The comprehensive mzTab specification document and extensive additional documentation can be found online.

Proliferation capacity and cytotoxic activity are mediated by functionally and phenotypically distinct virus-specific CD8 T cells defined by interleukin-7R{alpha} (CD127) and perforin expression.

Cytotoxicity and proliferation capacity are key functions of antiviral CD8 T cells. In the present study, we investigated a series of markers to define these functions in virus-specific CD8 T cells. We provide evidence that there is a lack of coexpression of perforin and CD127 in human CD8 T cells. CD127 expression on virus-specific CD8 T cells correlated positively with proliferation capacity and negatively with perforin expression and cytotoxicity. Influenza virus-, cytomegalovirus-, and Epstein-Barr virus/human immunodeficiency virus type 1-specific CD8 T cells were predominantly composed of CD127(+) perforin(-)/CD127(-) perforin(+), and CD127(-)/perforin(-) CD8 T cells, respectively. CD127(-)/perforin(-) and CD127(-)/perforin(+) cells expressed significantly more PD-1 and CD57, respectively. Consistently, intracellular cytokine (gamma interferon, tumor necrosis factor alpha, and interleukin-2 [IL-2]) responses combined to perforin detection confirmed that virus-specific CD8 T cells were mostly composed of either perforin(+)/IL-2(-) or perforin(-)/IL-2(+) cells. In addition, perforin expression and IL-2 secretion were negatively correlated in virus-specific CD8 T cells (P &lt; 0.01). As previously shown for perforin, changes in antigen exposure modulated also CD127 expression. Based on the above results, proliferating (CD127(+)/IL-2-secreting) and cytotoxic (perforin(+)) CD8 T cells were contained within phenotypically distinct T-cell populations at different stages of activation or differentiation and showed different levels of exhaustion and senescence. Furthermore, the composition of proliferating and cytotoxic CD8 T cells for a given antiviral CD8 T-cell population appeared to be influenced by antigen exposure. These results advance our understanding of the relationship between cytotoxicity, proliferation capacity, the levels of senescence and exhaustion, and antigen exposure of antiviral memory CD8 T cells.

Long-term health-related quality of life and walking capacity of lung recipients with and without bronchiolitis obliterans syndrome.

BACKGROUND: Outcome after lung transplantation (LTx) is affected by the onset of bronchiolitis obliterans syndrome (BOS) and lung function decline. Reduced health-related quality of life (HRQL) and physical mobility have been shown in patients developing BOS, but the impact on the capacity to walk is unknown. We aimed to compare the long-term HRQL and 6-minute walk test (6MWT) between lung recipients affected or not by BOS Grade > or =2. METHODS: Fifty-eight patients were prospectively followed for 5.6 +/- 2.9 years after LTx. Assessments included the St George's Respiratory Questionnaire (SGRQ) and the 6MWT, which were performed yearly. Moreover, clinical complications were recorded to estimate the proportion of the follow-up time lived without clinical intercurrences after transplant. Analyses were performed using adjusted linear regression and repeated-measures analysis of variance. RESULTS: BOS was a significant predictor of lower SGRQ scores (p < 0.01) and reduced time free of clinical complications (p = 0.001), but not of 6MWT distance (p = 0.12). At 7 years post-transplant, results were: 69.0 +/- 21.8% vs 86.9 +/- 5.6%, p < 0.05 (SGRQ); 58.5 +/- 21.6% vs 88.7 +/- 11.4%, p < 0.01 (proportion of time lived without clinical complications); and 82.2 +/- 10.9% vs 91.9 +/- 14.2%, p = 0.27 (percent of predicted 6MWT), respectively, for patients with BOS and without BOS. CONCLUSIONS: Despite significantly less time lived without clinical complications and progressive decline of self-reported health status, the capacity to walk of patients affected by BOS remained relatively stable over time. These findings may indicate that the development of moderate to severe BOS does not prevent lung recipients from walking independently and pursuing an autonomous life.

Assessment of the capacity to consent to treatment in patients admitted to acute medical wards

RAPPORT DE SYNTHÈSE : Introduction: L'évaluation de la capacité de discernement est importante d'un point de vue légal et éthique dans l'activité médicale quotidienne. Dans cette étude, nous avons évalué attentivement la capacité de discernement chez les patients admis dans un service médical aigu en utilisant l'évaluation du personnel médical, le score spécifique de Silberfeld, le MMSE ainsi que l'évaluation du psychiatre. Méthode : Pendant 3 mois, 195 patients admis dans un service de médecine interne d'un hôpital universitaire ont été inclus et leur capacité de discernement a été évaluée durant les premières 72 heures d'admission. Résultats : Sur les 195 patients, 38 furent incapables de discernement manifestement (patients inconscients ou avec des déficits cognitifs sévères) et 14 furent considérés incapables de discernement par le psychiatre (prévalence de l'incapacité de discernement de 26.7%). La corrélation entre l'évaluation du psychiatre et le questionnaire de Silberfeld fut faible (sensibilité 35.7%, spécificité 91.6%). Les cliniciens expérimentés montrèrent une plus haute corrélation (sensibilité 57.1 %, spécificité 96.5%). L'avis partagé par l'assistant, par le chef de clinique et l'infirmière se révéla le meilleur indicateur de l'évaluation psychiatrique (sensibilité 78.6%, spécificité 94.3%). Conclusion : La prévalence de l'incapacité de discernement chez les patients admis dans un service de médecine interne est élevée. Alors que le questionnaire de Silberfeld et le MMSE ne sont pas indiqués pour évaluer la capacité de discernement dans cette étude, l'évaluation par une équipe médicale multidisciplinaire reflète le mieux l'évaluation du psychiatre.

Role of oxidative stress in plasticity of Dendritic cells

Dendritic cells (DCs) are antigen presenting cells with an unique ability to induce primary immune responses. Different DCs subsets with an intrinsic capacity to polarise Tcells have been described: myeloid (Th1) and lymphoid (Th2). Plasticity is defined as DCs capacity to polarise T cells independent of the DCs origin. We investigated the potential role played by oxidants such as superoxide anion (·O2-), in the plasticity of DCs, measured by the induction of a specific DCs subset, cytokine release and antigen presentation. Furthermore, we are interested in the amplification of immune response analysed by the exosomes production after oxidative stress and LPS stimulation. Recently, we have demonstrated that exposure of cells to superoxide anions resulted in the activation of DC2 profile. To analyse the role of oxidative stress in DCs subsets, we used BDCA-1 and BDCA-2 antibodies, which identify myeloid and plasmacytoid DCs respectively. Freshly isolated monocytes have shown to be BDCA-1-, but BDCA-2+ populations. During 6 days culture up-regulation of BDCA-1, but a down-regulation of BDCA-2 were observed, giving a clear myeloid population. When DC were stimulated with superoxide anions or LPS, we have observed that both down regulate the expression of BDCA-1 when compared to immature DC. Antigen presentation was markedly altered according to the periodicity used, and antigens and oxidants exposures. Using DCs trapped in collagen "matrix" after LPS activation we were able to quantify DCs-exosomes (small membrane vesicles ~50-100 nm in diameter) by reconstruction pictures in three dimensions. Using double vital staining we have found that exosomes from activated DCs can fuse with the membrane of resting DCs. Understanding the capacity of DCs to integrate external signals we will be able to unravel and control Tcells-polarisation triggering a specific immune response or tolerance. We will be able also to understand the amplification role of DCs-exosomes in remote not yet activated DCs.

Transfer factor for carbon monoxide: a glance behind the scene.

The transfer factor for carbon monoxide (TLCO) is widely used in pulmonary function laboratories because it represents a unique non-invasive window on pulmonary microcirculation. The TLCO is the product of two primary measurements, the alveolar volume (VA) and the CO transfer coefficient (KCO). This test is most informative when VA and KCO are examined, together with their product TLCO. In a normal lung, a low VA due to incomplete expansion is associated with an elevated KCO, resulting in a mildly reduced TLCO. Thus, in case of low VA, a seemingly "normal KCO" must be interpreted as an abnormal gas transfer. The most common clinical conditions associated with an abnormal TLCO are characterised by a limited number of patterns for VA and KCO: incomplete lung expansion, discrete loss of alveolar units, diffuse loss of alveolar units, emphysema, pulmonary vascular disorders, high pulmonary blood volume, alveolar haemorrhage.

Aerobic and functional capacities in a selected active population of European octogenarians

Master athletes are often considered to represent the ideal rate of decline of aerobic function; however, most of the studies interested in active elderly people are often limited to people younger than 75. We aimed to determine the physiological adaptations and aerobic fitness in a selected European population of active octogenarians during maximal and submaximal exercise tests. Aerobic capacity was measured during maximal incremental tests on treadmill (TR) and cycle-ergometer (CE) and functional capacity during a 6-minute walk test (6-MWT) in 17 subjects aged 81.2 +/- 0.8 years. Pulmonary gas exchange and heart rate (HR) were continuously measured during the different exercise tests. Maximal oxygen consumption (V.O (2max)) on TR and CE was significantly higher than predicted values (TR: 28.7 +/- 1.2 vs. 17 +/- 0.5 ml . kg (-1) . min (-1); CE: 23 +/- 1.2 vs. 16 +/- 0.6 ml . kg (-1) . min (-1) for measured and predicted values respectively). V.O (2max) and HR (max), as well as V.O (2) and HR at the ventilatory threshold (V.O (2)T (V.E) and HR T (V.E)) were significantly higher on TR than on CE (HR (max): 144 +/- 4 vs. 138 +/- 4 bpm; V.O (2)T (V.E): 22.5 +/- 0.8 vs. 17.7 +/- 0.9 ml . kg (-1) . min (-1) for TR and CE respectively). V.O (2)T (V.E) and HR T (V.E) on TR were equivalent to V.O (2) and HR measured during the 6-MWT. HR T (V.E) on TR and mean HR during the 6-MWT were strongly correlated (R = 0.82, p < 0.01). Maintenance of regular physical activity provides high aerobic fitness, in octogenarians, as was shown by the higher values of our subjects in comparison to predicted values. Moreover, the close relation between the intensity developed at T (V.E) on TR and 6-MWT could support the idea that a walk test is a submaximal test performed at high intensity that could provide a basis for exercise prescription in an individualized manner in active elderly people.