Post-exercise heart rate recovery and mortality in chronic obstructive pulmonary disease

SummaryAbnormal heart rate recovery (HRR) after exercise, a marker of cardiac autonomic dysfunction, is associated with poor prognosis in various populations. As chronic obstructive pulmonary disease (COPD) is associated with cardiac autonomic dysfunction, we tested the hypothesis that patients with COPD have a lower HRR than healthy people, and evaluated whether a delay in HRR is associated with an increased risk of mortality in COPD. The records of 147 COPD patients were reviewed (65.1±9.1 years, mean±sd, 42 women/105 men, forced expiratory volume in 1s (FEV1): 42±15% predicted) and compared to 25 healthy subjects (61.6±4.5 years, 5 women/20 men, FEV1: 100±14% predicted) during recovery after an exercise test. Heart rate was measured at peak exercise and at 1-min recovery, the difference between the two being defined as HRR (11±9 beats in COPD patients vs. 20±9 beats in healthy subjects, P<0.0001). During a mean follow-up of 43.1±22.0 months, 32 patients died. Abnormal HRR (⩽14 beats) was a strong predictor of mortality in COPD patients (adjusted hazard ratio: 5.12, 95% CI [1.54–17.00]). In conclusion, COPD patients have a lower HRR than healthy subjects, and have a worse prognosis when presenting abnormal HRR

Dinitrogen fixation and dissolved organic nitrogen fueled primary production and particulate export during the VAHINE mesocosm experiment (New Caledonia lagoon)

International audienceIn the oligotrophic ocean characterized by nitrate (NO − 3) depletion in surface waters, dinitrogen (N 2) fixation and dissolved organic nitrogen (DON) can represent significant nitrogen (N) sources for the ecosystem. In this study, we deployed large in situ mesocosms in New Caledonia in order to investigate (1) the contribution of N 2 fixation and DON use to primary production (PP) and particle export and (2) the fate of the freshly produced particulate organic N (PON), i.e., whether it is preferentially accumulated and recycled in the water column or exported out of the system. The mesocosms were fertilized with phosphate (PO 3− 4) in order to prevent phosphorus (P) limitation and promote N 2 fixation. The diazotrophic community was dominated by diatom–diazotroph associations (DDAs) during the first part of the experiment for 10 days (P1) followed by the unicel-lular N 2-fixing cyanobacteria UCYN-C for the last 9 days (P2) of the experiment. N 2 fixation rates averaged 9.8 ± 4.0 and 27.7 ± 8.6 nmol L −1 d −1 during P1 and P2, respectively. NO − 3 concentrations ( 0.05) during P1 (9.0 ± 3.3 %) and P2 (12.6 ± 6.1 %). However, the e ratio that quantifies the efficiency of a system to export particulate organic carbon (POC export) compared to PP (e ratio = POC export / PP) was significantly higher (p 0.05) from the total amount of PON exported (0.10 ± 0.04 µmol L −1), suggesting a rapid and probably direct export of the recently fixed N 2 by the DDAs. During P2, both PON concentrations and PON export increased in the mesocosms by a factor 1.5–2. Unlike in P1, this PON production was not totally explained by the new N provided by N 2 fixation. The use of DON, whose concentrations decreased significantly (p < 0.05) from 5.3 ± 0.5 µmol L −1 to 4.4 ± 0.5 µmol L −1 , appeared to be the missing N source. The DON consumption (∼ 0.9 µmol L −1) during P2 is higher Published by Copernicus Publications on behalf of the European Geosciences Union. 4100 H. Berthelot et al.: Dinitrogen fixation and dissolved organic nitrogen fueled primary production than the total amount of new N brought by N 2 fixation (∼ 0.25 µmol L −1) during the same period. These results suggest that while DDAs mainly rely on N 2 fixation for their N requirements, both N 2 fixation and DON can be significant N sources for primary production and particulate export following UCYN-C blooms in the New Caledonia lagoon and by extension in the N-limited oceans where similar events are likely to occur

Effects of increased pCO2 and temperature on the North Atlantic spring bloom. III. Dimethylsulfoniopropionate

The CLAW hypothesis argues that a negative feedback mechanism involving phytoplankton- derived dimethylsulfoniopropionate (DMSP) could mitigate increasing sea surface temperatures that result from global warming. DMSP is converted to the climatically active dimethylsulfide (DMS), which is transferred to the atmosphere and photochemically oxidized to sulfate aerosols, leading to increases in planetary albedo and cooling of the Earth’s atmosphere. A shipboard incubation experiment was conducted to investigate the effects of increased temperature and pCO2 on the algal community structure of the North Atlantic spring bloom and their subsequent impact on particulate and dissolved DMSP concentrations (DMSPp and DMSPd). Under ‘greenhouse’ conditions (elevated pCO2; 690 ppm) and elevated temperature (ambient + 4°C), coccolithophorid and pelagophyte abundances were significantly higher than under control conditions (390 ppm CO2 and ambient temperature). This shift in phytoplankton community structure also resulted in an increase in DMSPp concentrations and DMSPp:chl a ratios. There were also increases in DMSP-lyase activity and biomass-normalized DMSP-lyase activity under ‘greenhouse’ conditions. Concentrations of DMSPd decreased in the ‘greenhouse’ treatment relative to the control. This decline is thought to be partly due to changes in the microzooplankton community structure and decreased grazing pressure under ‘greenhouse’ conditions. The increases in DMSPp in the high temperature and greenhouse treatments support the CLAW hypothesis; the declines in DMSPd do not

Organizational Knowledge Translation Strategies for Allied Health Professionals in Traumatology Settings: A Realist Review Protocol.

Background Knowledge translation (KT) is an important means of improving the health service quality. Most research on the effectiveness of KT strategies has focused on individual strategies, i.e., those directly targeting the modification of allied health professionals’ knowledge, attitudes, and behaviors, for example. In general, these strategies are moderately effective in changing practices (maximum 10% change). Effecting change in organizational contexts (e.g., change readiness, general and specific organizational capacity, organizational routines) is part of a promising new avenue to service quality improvement through the implementation of evidence-based practices. The objective of this study will be to identify why, how, and under what conditions organizational KT strategies have been shown to be effective or ineffective in changing the (a) knowledge, (b) attitudes, and (c) clinical behaviors of allied health professionals in traumatology settings. Methods This is a realist review protocol involving four iterative steps: (1) Initial theory formulation, (2) search for Evidence search, (3) knowledge extraction and synthesis, and (4) recommendations. We will search electronic databases such as PubMed, Embase, CINHAL, Cochrane Library, and Conference Proceedings Citation Index - Science. The studies included will be those relating to the use of organizational KT strategies in trauma settings, regardless of study designs, published between January 1990 and October 2020, and presenting objective measures that demonstrate change in allied health professionals’ knowledge, attitudes, and clinical behaviors. Two independent reviewers will select, screen, and extract the data related to all relevant sources in order to refine or refute the context-mechanism-outcome (CMO) configurations developed in the initial theory and identify new CMO configurations. Discussion Using a systematic and rigorous method, this review will help guide decision-makers and researchers in choosing the best organizational strategies to optimize the implementation of evidence-based practices

A collaborative model to implement flexible, accessible and efficient oncogenetic services for hereditary breast and ovarian cancer : the C-MOnGene study

Medical genetic services are facing an unprecedented demand for counseling and testing for hereditary breast and ovarian cancer (HBOC) in a context of limited resources. To help resolve this issue, a collaborative oncogenetic model was recently developed and implemented at the CHU de Québec-Université Laval; Quebec; Canada. Here, we present the protocol of the C-MOnGene (Collaborative Model in OncoGenetics) study, funded to examine the context in which the model was implemented and document the lessons that can be learned to optimize the delivery of oncogenetic services. Within three years of implementation, the model allowed researchers to double the annual number of patients seen in genetic counseling. The average number of days between genetic counseling and disclosure of test results significantly decreased. Group counseling sessions improved participants' understanding of breast cancer risk and increased knowledge of breast cancer and genetics and a large majority of them reported to be overwhelmingly satisfied with the process. These quality and performance indicators suggest this oncogenetic model offers a flexible, patient-centered and efficient genetic counseling and testing for HBOC. By identifying the critical facilitating factors and barriers, our study will provide an evidence base for organizations interested in transitioning to an oncogenetic model integrated into oncology care; including teams that are not specialized but are trained in genetics

Association of anthropometry and weight change with risk of dementia and its major subtypes : A meta-analysis consisting 2.8 million adults with 57 294 cases of dementia

Uncertainty exists regarding the relation of body size and weight change with dementia risk. As populations continue to age and the global obesity epidemic shows no sign of waning, reliable quantification of such associations is important. We examined the relationship of body mass index, waist circumference, and annual percent weight change with risk of dementia and its subtypes by pooling data from 19 prospective cohort studies and four clinical trials using meta-analysis. Compared with body mass index-defined lower-normal weight (18.5-22.4 kg/m(2)), the risk of all-cause dementia was higher among underweight individuals but lower among those with upper-normal (22.5-24.9 kg/m(2)) levels. Obesity was associated with higher risk in vascular dementia. Similarly, relative to the lowest fifth of waist circumference, those in the highest fifth had nonsignificant higher vascular dementia risk. Weight loss was associated with higher all-cause dementia risk relative to weight maintenance. Weight gain was weakly associated with higher vascular dementia risk. The relationship between body size, weight change, and dementia is complex and exhibits non-linear associations depending on dementia subtype under scrutiny. Weight loss was associated with an elevated risk most likely due to reverse causality and/or pathophysiological changes in the brain, although the latter remains speculative.Peer reviewe

Instruments to assess the perception of physicians in the decision-making process of specific clinical encounters: a systematic review

<p>Abstract</p> <p>Background</p> <p>The measurement of processes and outcomes that reflect the complexity of the decision-making process within specific clinical encounters is an important area of research to pursue. A systematic review was conducted to identify instruments that assess the perception physicians have of the decision-making process within specific clinical encounters.</p> <p>Methods</p> <p>For every year available up until April 2007, PubMed, PsycINFO, Current Contents, Dissertation Abstracts and Sociological Abstracts were searched for original studies in English or French. Reference lists from retrieved studies were also consulted. Studies were included if they reported a self-administered instrument evaluating physicians' perceptions of the decision-making process within specific clinical encounters, contained sufficient description to permit critical appraisal and presented quantitative results based on administering the instrument. Two individuals independently assessed the eligibility of the instruments and abstracted information on their conceptual underpinnings, main evaluation domain, development, format, reliability, validity and responsiveness. They also assessed the quality of the studies that reported on the development of the instruments with a modified version of STARD.</p> <p>Results</p> <p>Out of 3431 records identified and screened for evaluation, 26 potentially relevant instruments were assessed; 11 met the inclusion criteria. Five instruments were published before 1995. Among those published after 1995, five offered a corresponding patient version. Overall, the main evaluation domains were: satisfaction with the clinical encounter (n = 2), mutual understanding between health professional and patient (n = 2), mental workload (n = 1), frustration with the clinical encounter (n = 1), nurse-physician collaboration (n = 1), perceptions of communication competence (n = 2), degree of comfort with a decision (n = 1) and information on medication (n = 1). For most instruments (n = 10), some reliability and validity criteria were reported in French or English. Overall, the mean number of items on the modified version of STARD was 12.4 (range: 2 to 18).</p> <p>Conclusion</p> <p>This systematic review provides a critical appraisal and repository of instruments that assess the perception physicians have of the decision-making process within specific clinical encounters. More research is needed to pursue the validation of the existing instruments and the development of patient versions. This will help researchers capture the complexity of the decision-making process within specific clinical encounters.</p

Variabilité spatiale et temporelle du cycle du silicium dans divers milieux oligotrophes et mésotrophes

The silicon biogeochemical cycle was studied in diverse coastal and oceanic systems, oligotroph to mesotroph, in the Mediterranean Sea (SOFi, ALMOFRONT II and PROSOPE campains), in the North East Atlantic (POMME campaign) and in the HNLCLSi area of the Indian sector of the Southern Ocean (ANTARES 4 campaign). This work has evidenced the role of the availability of dissolved Si upon diatom distribution in the western Mediterranean, where silicic acid stocks can be inferior to nitrate stocks. Silicic acid concentrations can be very low and close to the detection limit in coastal systems (Gulf of Lions) as well as in open systems (Alboran Sea, Algerian Basin), contradicting the current assumption that dissolved silicon is never found below 1 μM in the Mediterranean. Si uptake kinetics carried out during the POMME and SOFi campaigns highlighted Si limitation at relatively high concentrations (≥ 1 μM). The half-saturation constants for Si uptake varied strongly depending on the specific structure of the diatom assemblage. Nutrient enrichment experiments performed during the POMME and ANTARES 4 campaigns have showned Si/Fe and Si/N co-limitation processes liable to limit the diatom spring bloom in the North East Atlantic and in the Southern Ocean HNLCLSi area. If dissolved Si availability does not seem to directly control primary production, its role appears crucial in structuring the specific composition of the phytoplankton assemblage, by favouring or not the dominance of diatoms, one of the main group responsible for rapid C export to depth. Results obained throughout the different campaigns illustrated the potential importance of Si dissolution in the euphotic layer, when silicic acid concentrations are low. This process may be of particular importance during the spring bloom, by allowing a replenishment of the depleted surface layer and inducing a production regime based on regenerated Si. Finally, production and exportation budgets established for each system studied allowed the comparison with the functionning of other oceanic systems. The SOFi study siteexhibited an extremely low annual production budget as compared to other coastal systems, which was the result of the oligotrophic conditions induced by the Northern Mediterranean Current. Paradoxically, this site appeared to be a privileged area of Si sedimentation, with 64 % of the produced biogenic silica exported out of the euphotic layer. The highest production rates were on the other hand measured during the spring bloom in the North Atlantic, where very low exportation rates were recorded (3-4 %). The decoupling between Si production and exportation thus indicates distinct processes controlling the siliceous biomass in the different system studied. Furthermore, the Si/C decoupling in each compartiment (production, stock, exportation) also exhibited significant differences.Le cycle biogéochimique du silicium en milieu marin a été étudié dans divers systèmes océaniques et côtiers, oligotrophes à mésotrophes, en Méditerranée (campagnes SOFi, ALMOFRONT II, PROSOPE), en Atlantique Nord-Est (campagne POMME), et dans la zone HNLCLSi (High Nutrient Low Chlorophyll Low Silicate) du secteur Indien de l’Océan Austral (campagne ANTARES 4). Ce travail a mis en évidence le rôle de la disponibilité en Si dissous sur la distribution des diatomées à l’échelle de la Méditerranée Occidentale, où les stocks d’acide silicique peuvent s’avérer déficitaires par rapport aux stocks de nitrates et de phosphates. Par ailleurs, les concentrations en Si(OH) 4 peuvent atteindre régulièrement des valeurs proches ou inférieures à la limite de détection, que ce soit en milieu côtier (Golfe du Lion) ou en milieu océanique ouvert (mer d’Alboran, bassin Algérien), allant à l’encontre de l’assertion couramment admise que les concentrations en Si(OH) 4 ne sont jamais inférieures à 1 μM en Méditerranée. Les cinétiques d’absorption du Si réalisées au cours des campagnes POMME et SOFi ont mis en évidence des processus de limitation des taux d’absorption à des concentrations non nulles (de l’ordre de 1 μM) en acide silicique. Les constantes dedemi-saturation (K S ) mesurées semblent varier fortement en fonction de la structure spécifique de l’assemblage de diatomées en présence. Des expériences d’enrichissement réalisées au cours des campagnes POMME et ANTARES 4 ont également mis en évidence des processus de co-limitation Si/Fe et Si/N susceptibles de limiter la floraison printanière des diatomées en Atlantique Nord-Est et dans la zone HNLCLSi de l’Océan Austral. Si la disponibilité en Si dissous ne semble pas contrôler directement le niveau de la production primaire, son rôle apparaît cependant essentiel en tant que facteur de contrôle de la structure spécifique de l’assemblage phytoplanctonique, en permettant la dominance ou non des diatomées, principal groupe responsable de l’exportation rapide de matière vers le fond. Les résultats acquis au cours des différentes campagnes illustrent l’importance potentielle des processus de dissolution de la silice biogénique dans la couche euphotique lorsque les concentrations en acide silicique sont faibles, notamment au moment de la floraison printanière, en permettant un ré-approvisionnement de la couche de surface et un fonctionnement des diatomées en mode de production régénérée sur le Si. Par ailleurs les bilans de production et d’exportation de Si réalisés dans chaque zone ont permis de replacer les sites étudiés dans le contexte des grands systèmes océaniques. Le site SOFi présente un bilan annuel de production de Si extrêmement faible par rapport aux zones côtières précédemment décrites, notamment en raison des conditions oligotrophes induites par le courant Nord- Méditerranéen, mais se révèle être un site d’exportation privilégié de Si, avec une moyenne annuelle d’exportation équivalente à 64 % de la production de Si dans la couche euphotique. Le bilan de production le plus élevé est observé dans l’Atlantique Nord en période printanière, en revanche cette zone est caractérisée par de faibles flux d’exportation de Si (de l’ordre de 3-4 %). Les processus de découplage Si/C au sein des différents compartiments (production, stocks, exportation) montrent de la même façon des différences importantes selon les systèmes étudiés

New observations on the Antarctic Asteromphalus darwinii/ hookeri diatom species-complex (Asterolampraceae)

Antarctic diatom populations of Asteromphalus hookeri and related species such as A. hyalinus and A. parvulus exhibit a highly variable number of hyaline rays ranging from 3 broad + 1 narrow (3 + 1) in the smallest valves, with 4 + 1 (27%) and 5 + 1 rays (35%) most common, and 6 + 1, 7 + 1, and rarely 8 + 1 rays only in larger cells. During December 1959 to April 1960 in the southern sector of the Atlantic Ocean, 6% of valves occurred as “double forms” with epitheca and hypotheca of the same cell exhibiting 4 + 1/3 + 1, 5 + 1/4 + 1, 6 + 1/5 + 1 and 7 + 1/6 + 1 ray combinations. Smaller cells (3 + 1, 4 + 1) always exhibited jagged separation lines in the central area, but larger cells (7 + 1, 8 + 1) had mostly smooth lines, and either jagged or smooth separation lines occurred in intermediate 5 + 1 and 6 + 1 forms, respectively. Epitheca and hypotheca of one and the same cell always exhibited jagged or smooth separation lines, but never mixtures. Observations of silica deposition during October to November 2011 around the Kerguelen Island plateau using the PDMPO fluorescent marker suggest that Asteromphalus separation lines play a key role in silica cell wall development. We discuss implications for taxonomy and our understanding of ecophysiology of what we designate as two highly variable and often confused and overlapping diatom taxa, A.darwiniii (jagged separation lines; synonyms A. beaumontii, A. hyalinus, A. leboimei, A. parvulus, A. rossii) and A. hookeri (smooth separation lines; synonym A. antarcticus, A.buchii, ?cuvierii, ?humboldtii)