Cortisol and Subjective Stress Responses to Acute Psychosocial Stress in Fibromyalgia Patients and Control Participants

OBJECTIVE: Hypothalamic-pituitary-adrenal (HPA) axis dysfunction may play a role in fibromyalgia (FM) pathogenesis, but remains understudied in this disorder. Furthermore, early childhood adversities (ECA) are common in FM, but whether they moderate stress reactivity is unknown. Hence, we investigated cortisol and subjective responses to acute psychosocial stress in FM and controls, while adjusting for ECA. METHODS: Twenty-seven female FM patients and 24 age-matched female controls were recruited in a tertiary care center and through advertisements, respectively. The Childhood Trauma Questionnaire was used to measure ECA history. Salivary cortisol levels and subjective stress ratings were measured at multiple time points before and after the Trier Social Stress Test (TSST) was administered. RESULTS: Significant main effects of group [F(1,43)=7.04, p=0.011, lower in FM] and ECA [F(1,43)=5.18, p=0.028, higher in participants with ECA] were found for cortisol responses. When excluding controls with ECA (n=5), a significant group-by-time interaction was found [F(6,39)=2.60, p=0.032], driven by a blunted response to the stressor in FM compared with controls (p=0.037). For subjective stress responses, a significant main effect of group [F(1,45)=10.69, p=0.002, higher in FM] and a trend towards a group-by-time interaction effect [F(6,45)=2.05, p=0.078, higher in FM 30 minutes before and 30 and 75 minutes after the TSST, and impaired recovery (difference immediately after - 30 minutes after the TSST) in FM] were found. CONCLUSIONS: Blunted cortisol responsivity to the TSST was observed in FM patients compared with controls without ECA. FM patients had higher subjective stress levels compared with controls, particularly at baseline and during recovery from the TSST. In FM patients, ECA history was not associated with cortisol or subjective stress levels, or with responsivity to the TSST. Future research should investigate the mechanisms underlying HPA axis dysregulation in FM

Prevalence and impact of childhood adversities and post-traumatic stress disorder in women with fibromyalgia and chronic widespread pain.

OBJECTIVE: This study investigates the prevalence of different types of childhood adversities (CA) and posttraumatic stress disorder (PTSD) in female patients with Fibromyalgia or Chronic Widespread Pain (FM/CWP) compared to patients with Functional Dyspepsia (FD) and achalasia. In FM/CWP, we also investigated the association between CA and PTSD on the one hand and pain severity on the other. METHODS: Patient samples consisted of 154 female FM/CWP, 83 female FD and 53 female achalasia patients consecutively recruited from a tertiary care hospital. Well-validated self-report questionnaires were used to investigate CA and PTSD. RESULTS: Forty-nine per cent of FM/CWP patients reported at least 1 type of CA, compared to 39.7% of FD patients and 23.4% of achalasia patients (p < 0.01). The prevalence of CA did not differ significantly between FM/CWP and FD, but both groups had a higher prevalence of CA compared to both achalasia and healthy controls (p < 0.01). FM/CWP patients were six times more likely to report PTSD than both FD (p < 0.001) and achalasia (p < 0.001) patients. CONCLUSION: In FM/CWP, PTSD comorbidity, but not CA, was associated with self-reported pain severity and PTSD severity mediated the relationship between CA and pain severity. In summary, the prevalence of CA is higher in FM/CWP compared to achalasia, but similar to FD. However, PTSD is more prevalent in FM/CWP compared to FD and associated with higher pain intensity in FM/CWP. SIGNIFICANCE: As expected and has been shown in other functional disorders, we found elevated levels of childhood adversity in FM/CWP patients. Results of this study however suggest that the impact of childhood adversity (i.e. whether such events have led to the development of PTSD symptoms), rather than the mere presence of such adversity, is of crucial importance in FM/CWP patients. Screening for PTSD symptoms should be an essential part of the assessment process in patients suffering from FM/CWP, and both prevention and intervention efforts should take into account PTSD symptoms and their impact on pain severity and general functioning

Insights Into the Biogeochemical Cycling of Iron, Nitrate, and Phosphate Across a 5,300 km South Pacific Zonal Section (153°E–150°W)

Iron, phosphate and nitrate are essential nutrients for phytoplankton growth and hence their supply into the surface ocean controls oceanic primary production. Here, we present a GEOTRACES zonal section (GP13; 30-33oS, 153oE-150oW) extending eastwards from Australia to the oligotrophic South Pacific Ocean gyre outlining the concentrations of these key nutrients. Surface dissolved iron concentrations are elevated at >0.4 nmol L-1 near continental Australia (west of 165°E) and decreased eastward to ≤0.2 nmol L-1 (170oW-150oW). The supply of dissolved iron into the upper ocean (<100m) from the atmosphere and vertical diffusivity averaged 11 ±10 nmol m-2 d-1. In the remote South Pacific Ocean (170oW-150oW) atmospherically sourced iron is a significant contributor to the surface dissolved iron pool with average supply contribution of 23 ± 17% (range 3% to 55%). Surface-water nitrate concentrations averaged 5 ±4 nmol L-1 between 170oW and 150oW whilst surface-water phosphate concentrations averaged 58 ±30 nmol L-1. The supply of nitrogen into the upper ocean is primarily from deeper waters (24-1647 μmol m-2 d-1) with atmospheric deposition and nitrogen fixation contributing <1% to the overall flux, in remote South Pacific waters. The deep water N:P ratio averaged 16 ±3 but declined to <1 above the deep chlorophyll maximum (DCM) indicating a high N:P assimilation ratio by phytoplankton leading to almost quantitative removal of nitrate. The supply stoichiometry for iron and nitrogen relative to phosphate at and above the DCM declines eastward leading to two biogeographical provinces: one with diazotroph production and the other without diazotroph production

Seasonal variation of bacterial production, respiration and growth efficiency in the open NW Mediterranean Sea

International audienc

Atmospheric fluxes of soluble organic C, N, and P to the Mediterranean Sea: Potential biogeochemical implications in the surface layer

International audienceLinking atmospheric deposition to marine carbon and nutrient cycle is hampered by the lack of data on atmospheric fluxes of organic matter. To fill this gap, this study reports the first quantification of atmospheric fluxes of soluble organic carbon (SOC), nitrogen (SON) and phosphate (SOP) to the NW Mediterranean Sea. Simultaneous measurements of dissolved organic carbon (DOC), dissolved organic nitrogen (DON) and dissolved organic phosphate (DOP) in the surface mixed layer (SML) allowed estimating the potential contribution of atmospheric fluxes to marine DOC, DON and DOP inventories. We found an annual atmospheric flux of 59 mmol C m−2 year−1 for SOC, 16.4 mmol N m−2 year−1 for SON and 23.6 µmol P m−2 year−1 for SOP, with proportions of SON and SOP to total soluble nitrogen and phosphate of 40% and 25%, respectively. Assuming these annual fluxes valid for the entire western Mediterranean basin, atmospheric fluxes would be higher than DOC, DON and DOP fluxes from the Rhône River by a factor of 6, 17 and 2, for C, N and P, respectively. Inventories of DOC, DON and DOP in the surface mixed layer displayed similar trends over the study period with maximum values at the end of the stratification period. DOP contributed by 85 ± 11% to total dissolved phosphate (TDP) pool and exhibited a labile fraction (LDOP) of 27 ± 19%. The contribution of atmospheric deposition to the DOC, DON and DOP pools in the SML, estimated for the stratification period, was low for C (3%) and P (4.5%) and moderate for N (12%). The labile fraction of atmospheric SOP (LSOP) was quantified throughout the sampling period and showed a high variability ranging from 0 to 97%. Atmospheric fluxes of LSOP contributed by 7% to marine LDOP pool and could sustain up to 8% of the heterotrophic prokaryotic phosphate demand in the SML of the NW Mediterranean Sea during the stratification period. The results obtained in this study stress the need to include atmospheric fluxes of organic matter in marine biogeochemical models to achieve a more complete picture of carbon and nutrient cycle in the Mediterranean Sea

Transport protocols: limitations, evolution obstacles and solutions for an actual deployment in the Internet

International audienceThe Transport layer, designed for old networking contexts and now obsolete applications requirements, is inefficient. This paper discusses the reasons behind this inefficiency and the obstacles to the evolution of Transport protocols. The discussion is then extended to derive new requirements for the Transport layer, both functional and architectural, in order to ensure optimal performances in all current and future contexts. To meet these new requirements, a novel architectural design of the Inter-net Transport layer is proposed following a service-oriented and a component-based approach. The proposed solution allows for optimization of the Transport service performance, facilitation of its utilization, and is aimed at allowing the integration of new services as needed. 1. Introduction The Transport layer is one of the most important layers of the Internet communication protocol stack. Located between the application and the network layers, this layer is expected to take into account both the application feature/requirements and the underlying network capabilities/constraints in order to provide the best end-to-end communication service, matching as much as possible the application requirements, still taking into account the opportunities and limitations of the underlying network. In the last few decades, several new applications and networking technologies have emerged with very different requirements and characteristics, making initial Transport-level protocols (typically TCP and UDP in the Internet) no longer adapted. As a consequence , a lot of new Transport protocols and mechanisms have been proposed over the last 20 years in order to enhance both the Transport services offered to applications, and to optimize the usage of the different network technologies. Unfortunately, the factual observation is that all these new proposals are either not integrated in the actual operating systems (Windows, Linux, etc.), or hardly used in practice by the application developers, which in majority continue to use suboptimal TCP and UDP solutions. Since it is proved that these new propositions are widely more efficient than the actual used protocols, the main goals of this work are to identify the deploymen