Whole-lake experiments trace added terrestrial particulate organic carbon in benthic food webs of shallow lakes

Lake ecosystems are strongly linked to their terrestrial surroundings by material and energy fluxes across ecosystem boundaries. However, the contribution of terrestrial particulate organic carbon (tPOC) from annual leaf fall to lake food webs has not yet been adequately traced and quantified. In this study, we conducted whole-lake experiments to trace artificially added tPOC through the food webs of two shallow lakes of similar eutrophic status, but featuring alternative stable regimes (macrophyte rich vs. phytoplankton dominated). Lakes were divided with a curtain, and maize (Zea mays) leaves were added, as an isotopically distinct tPOC source, into one half of each lake. To estimate the balance between autochthonous carbon fixation and allochthonous carbon input, primary production and tPOC and tDOC (terrestrial dissolved organic carbon) influx were calculated for the treatment sides. We measured the stable isotope ratios of carbon (δ13C) of about 800 samples from all trophic consumer levels and compared them between lake sides, lakes, and three seasons. Leaf litter bag experiments showed that added maize leaves were processed at rates similar to those observed for leaves from shoreline plants, supporting the suitability of maize leaves as a tracer. The lake-wide carbon influx estimates confirmed that autochthonous carbon fixation by primary production was the dominant carbon source for consumers in the lakes. Nevertheless, carbon isotope values of benthic macroinvertebrates were significantly higher with maize additions compared to the reference side of each lake. Carbon isotope values of omnivorous and piscivorous fish were significantly affected by maize additions only in the macrophyte-dominated lake and δ13C of zooplankton and planktivorous fish remained unaffected in both lakes. In summary, our results experimentally demonstrate that tPOC in form of autumnal litterfall is rapidly processed during the subsequent months in the food web of shallow lakes and is channeled to secondary and tertiary consumers predominantly via the benthic pathways. A more intense processing of tPOC seems to be connected to a higher structural complexity in littoral zones, and hence may differ between shallow lakes of alternative stable states

The first global deep-sea stable isotope assessment reveals the unique trophic ecology of Vampire Squid Vampyroteuthis infernalis (Cephalopoda)

Vampyroteuthis infernalis Chun, 1903, is a widely distributed deepwater cephalopod with unique morphology and phylogenetic position. We assessed its habitat and trophic ecology on a global scale via stable isotope analyses of a unique collection of beaks from 104 specimens from the Atlantic, Pacific and Indian Oceans. Cephalopods typically are active predators occupying a high trophic level (TL) and exhibit an ontogenetic increase in δ15N and TL. Our results, presenting the first global comparison for a deep-sea invertebrate, demonstrate that V. infernalis has an ontogenetic decrease in δ15N and TL, coupled with niche broadening. Juveniles are mobile zooplanktivores, while larger Vampyroteuthis are slow-swimming opportunistic consumers and ingest particulate organic matter. Vampyroteuthis infernalis occupies the same TL (3.0–4.3) over its global range and has a unique niche in deep-sea ecosystems. These traits have enabled the success and abundance of this relict species inhabiting the largest ecological realm on the planet.Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/. The attached file is the published pdf

Integrated monitoring of mola mola behaviour in space and time

Over the last decade, ocean sunfish movements have been monitored worldwide using various satellite tracking methods. This study reports the near-real time monitoring of finescale (< 10 m) behaviour of sunfish. The study was conducted in southern Portugal in May 2014 and involved satellite tags and underwater and surface robotic vehicles to measure both the movements and the contextual environment of the fish. A total of four individuals were tracked using custom-made GPS satellite tags providing geolocation estimates of fine-scale resolution. These accurate positions further informed sunfish areas of restricted search (ARS), which were directly correlated to steep thermal frontal zones. Simultaneously, and for two different occasions, an Autonomous Underwater Vehicle (AUV) videorecorded the path of the tracked fish and detected buoyant particles in the water column. Importantly, the densities of these particles were also directly correlated to steep thermal gradients. Thus, both sunfish foraging behaviour (ARS) and possibly prey densities, were found to be influenced by analogous environmental conditions. In addition, the dynamic structure of the water transited by the tracked individuals was described by a Lagrangian modelling approach. The model informed the distribution of zooplankton in the region, both horizontally and in the water column, and the resultant simulated densities positively correlated with sunfish ARS behaviour estimator (r(s) = 0.184, p < 0.001). The model also revealed that tracked fish opportunistically displace with respect to subsurface current flow. Thus, we show how physical forcing and current structure provide a rationale for a predator's finescale behaviour observed over a two weeks in May 2014

Myocardial changes detected with modern cardiac magnetic resonance techniques in patients with early rheumatoid arthritis

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): HUS diagnostic imaging center Aims Subclinical myocardial disease is common in patients with rheumatoid arthritis (RA). Impaired cardiac function, myocardial fibrosis and inflammation have previously correlated with RA disease activity. Our aim was to study whether myocardial changes are detectable by cardiac magnetic resonance (CMR) at the time of RA diagnosis. Material and methods: We recruited 21 untreated early RA patients without history of heart disease in Helsinki University Hospital and Lohja Hospital (Finland) between 10/2018 and 2/2020, and nine healthy volunteers. The patients underwent a clinical examination, laboratory tests, and CMR including mapping of extracellular volume fraction (ECV), and T1 and T2 relaxation times. The healthy controls underwent non-contrast CMR. Results  The RA patients were older than the controls (median 58.1 years vs. 41.6 years, respectively, table 1.). T1 was slightly higher in RA patients compared with healthy controls in anteroseptal segments (1015 ms vs. 982 ms, P = 0.017) (table 2).  No difference in T2 was detected and the ECV values were considered normal. Segmental T1, T2 or ECV showed no significant correlations with age, duration of the symptoms or with RA disease activity (DAS28-CRP score). Conclusions  The minor, but statistically significant, elevation of T1 relaxation time in the anteroseptal segments suggests that myocardial changes may occur already in the early phase of RA, the anteroseptal segments being most vulnerable. The elevation of T1 relaxation time can be caused by mild myocardial inflammation or fibrosis. Although no significant correlation with DAS28-CRP was observed, subclinical systemic inflammation may have contributed to the myocardial abnormalities. Table 1. Pre-contrast T1 relaxation time (ms) T2 relaxation time (ms) ECV (%) Mean RA patients Controls P-value RA patients Controls P-value RA patients Global myocardial mean 996 (978-1011) 982 (964-1000) 0.304 48.0 (44.6-49.7) 46.3 (44.1-48.7) 0.295 26.6 (25.7-28.5) Anterior segments 954 (919-1000) 951 (921-998) 0.929 47.7 (46.4-49.8) 47.9 (43.5-50.1) 0.871 26.7 (25.3-28.8) Anteroseptal segments 1015 (987-1041) 982 (947-996) 0.017 48.3 (45.5-49.9) 45.7 (43.8-48.4) 0.150 28.3 (26.8-29.2) Inferoseptal segments 1012 (992-1023) 998 (967-1003) 0.077 48.0 (43.5-49.4) 44.9 (43.5-46.2) 0.533 26.7 (26.0-27.9) Inferior segments 1016 (987-1064) 1003 (992-1025) 0.625 47.5 (45.1-50.3) 46.1 (44.2-48.4) 0.304 27.3 (25.6-29.0) Inferolateral segments 997 (974-1043) 992 (980-1016) &amp;gt;0.999 46.6 (42.6-49.1) 45.1 (42.4-49.1) 0.689 25.8 (25.3-28.2) Anterolateral segments 973 (945-973) 981 (954-1010) 0.563 47.0 (45.1-48.5) 46.6 (43.5-49.6) 0.625 26.4 (24.7-28.0) T1 and T2 relaxation time mapping and ECV results. Abstract Figure. ECV mapping </jats:sec

CMR 4D flow underestimates peak systolic flow measurements in patients with severe aortic stenosis

Abstract Funding Acknowledgements Type of funding sources: Public hospital(s). Main funding source(s): Helsinki University Hospital, Finland Background Aortic stenosis (AS) is the most prevalent valvular disease in the developed countries. 4D flow is an emerging cardiac magnetic resonance (CMR) imaging technique, which has been suggested to improve the evaluation of AS severity. The accuracy of peak flow measurement by 4D flow CMR in patients with severe AS has, however, remained unvalidated. Purpose We investigated the reliability of the novel 4D flow CMR technique in measuring transvalvular peak systolic flow in patients with severe aortic valve stenosis. Methods The study included 63 patients clinically evaluated for valve replacement due to severe symptomatic AS. All the patients underwent echocardiography, 2D phase-contrast and 4D flow CMR. CMR was performed on consecutive patients according to international guidelines. Mean age of the patients was 73.8 ± 11.5 years, mean aortic valve area 0.7 ± 0.2 cm², and 40 of the valves were tricuspid and 23 bicuspid. QFlow and QFlow 4D software were used for flow analyses. Bland-Altman analyses and Wilcoxon signed rank sum tests were performed using SPSS software. Results CMR 4D flow analyses underestimated peak flow values when compared with echocardiography (bias -1.1 m/s, limits of agreement ± 1.5 m/s) and with 2D flow analyses (bias -1.2 m/s, limits of agreement ± 1.7 m/s). The difference between values obtained by 4D flow (median 3.1 m/s, range 1.5 – 4.9 m/s) and echocardiography (median 4.3 m/s, range 2.1 – 6.1 m/s) as well as by 2D flow (median 4.3 m/s, range 2.0 – 8.4 m/s) were statistically significant (p &amp;lt; 0,001). The difference between 2D flow analyses and echocardiography remained statistically insignificant (bias 0.05 m/s, limits of agreement ± 1.6 m/s). Conclusions We found that 4D flow analysis significantly underestimates systolic peak flow values in patients with severe AS. This may be due to intra-voxel averaging of the narrow jets. In contrast to previous assumptions, traditional 2D flow technique may therefore outperform 4D flow in measuring valvular peak flow by CMR in patients with severe AS. This should be taken into consideration when assessing disease severity by CMR. Abstract Figure. Peak systolic flow in AS patients (n = 63) </jats:sec

Global longitudinal strain in patients with severe aortic stenosis: a comparison between cardiac magnetic resonance imaging feature tracking and speckle tracking echocardiography

Abstract Funding Acknowledgements Type of funding sources: None. Background Global longitudinal strain (GLS) by echocardiography is a sensitive method for measuring left ventricular (LV) function, and of better prognostic value in valvular heart disease than ejection fraction (EF). Cardiac magnetic resonance imaging (CMR) is the most accurate method for measuring LV volume and EF, but GLS has not been possible to measure by CMR until recently. Purpose This study compares GLS obtained by CMR and echocardiography in patients with severe aortic valve stenosis. Normal values for GLS by CMR are reported as well. Methods GLS was measured in 32 patients with severe aortic valve stenosis with speckle tracking echocardiography, using GE Vivid E95 (n = 15) and Philips EPIQ (n = 17) ultrasound machines, as well as with CMR (Avanto 1.5T FIT, Siemens Medical Solutions). For normal values, GLS was measured by CMR in 9 healthy controls. Endo- and epicardial borders of two, three and four chamber cine images were traced for CMR GLS using dedicated software (Qstrain 2.0, Medis, NL). Both CMR and Vivid E95 measured midmyocardial strain, whereas the EPIQ AutoStrain method measures endomyocardial strain. Absolute values of GLS are reported. Pearson correlation coefficient was calculated and paired Student’s t-test was used for comparisons. Results A significant correlation (r = 0.45, p = 0.01) was found between echocardiographic and CMR GLS (Figure). GLS by Vivid E95 had a very good correlation with CMR GLS (r = 0.84, p = 0.0001), whereas GLS by Philips EPIQ did not correlate significantly (r = 0.14, p = 0.01). In patients with aortic stenosis and healthy controls, the average GLS by CMR was 18.3 ± 3% and 20.9 ± 2% respectively. The average GLS by CMR was comparable to that obtained by GE Vivid E95 (17.3 ± 4% vs. 17.2 ± 3%, p = 0.92), and higher than by Philips EPIQ (19.2 ± 2% vs. 15.4 ± 2%, p &amp;lt; 0.0001). Conclusion This study shows that GLS by CMR is feasible and correlates with GLS obtained by echocardiography, especially when quantifying midmyocardial strain. Echocardiographic GLS values based on endomyocardial strain were lower. Patient characteristics Age 75 ± 14 y NYHA 1 1 (3 %) NYHA 2 20 (67 %) NYHA 3 8 (27 %) NYHA 4 1 (3 %) CMR EF 66 ± 8 % AVA 0.7 ± 0.2 cm&amp;sup2; NYHA = NYHA class of symptoms, EF = ejection fraction by CMR, AVA = aortic valve area by echocardiography Abstract Figure. GLS by CMR vs. Echocardiography </jats:sec

Inter- and intra-observer variability and the effect of experience in cine-MRI for adhesion detection

Cine-MRI for adhesion detection is a promising novel modality that can help the large group of patients developing pain after abdominal surgery. Few studies into its diagnostic accuracy are available, and none address observer variability. This retrospective study explores the inter- and intra-observer variability, diagnostic accuracy, and the effect of experience. A total of 15 observers with a variety of experience reviewed 61 sagittal cine-MRI slices, placing box annotations with a confidence score at locations suspect for adhesions. Five observers reviewed the slices again one year later. Inter- and intra-observer variability are quantified using Fleiss’ (inter) and Cohen’s (intra) κ and percentage agreement. Diagnostic accuracy is quantified with receiver operating characteristic (ROC) analysis based on a consensus standard. Inter-observer Fleiss’ κ values range from 0.04 to 0.34, showing poor to fair agreement. High general and cine-MRI experience led to significantly (p &lt; 0.001) better agreement among observers. The intra-observer results show Cohen’s κ values between 0.37 and 0.53 for all observers, except one with a low κ of −0.11. Group AUC scores lie between 0.66 and 0.72, with individual observers reaching 0.78. This study confirms that cine-MRI can diagnose adhesions, with respect to a radiologist consensus panel and shows that experience improves reading cine-MRI. Observers without specific experience adapt to this modality quickly after a short online tutorial. Observer agreement is fair at best and area under the receiver operating characteristic curve (AUC) scores leave room for improvement. Consistently interpreting this novel modality needs further research, for instance, by developing reporting guidelines or artificial intelligence-based methods

Mast cells in human and experimental cardiometabolic diseases

Mast cells, like many other types of inflammatory cell, perform pleiotropic roles in cardiometabolic diseases such as atherosclerosis, abdominal aortic aneurysms, obesity, and diabetes mellitus, as well as complications associated with these diseases. Low numbers of mast cells are present in the heart, aorta, and adipose tissue of healthy humans, but patients with cardiometabolic diseases and animals with experimentally-induced cardiometabolic pathologies have high numbers of mast cells with increased activity in the affected tissues. Mediators released by the activated mast cells, such as chemokines, cytokines, growth factors, heparin, histamine, and proteases, not only function as biomarkers of cardiometabolic diseases, but might also directly contribute to the pathogenesis of such diseases. Mast-cell mediators impede the functions of vascular cells, the integrity of the extracellular matrix, and the activity of other inflammatory cells, thereby contributing to the pathobiology of the conditions at multiple levels. In mouse models, mast-cell activation aggravates the progression of various cardiometabolic pathologies, whereas a genetic deficiency or pharmacological stabilization of mast cells, or depletion or inhibition of specific mast-cell mediators, tends to delay the progression of such conditions. Pharmacological inhibition of mast-cell activation or their targeted effector functions offers potential novel therapeutic strategies for patients with cardiometabolic disorders.Biopharmaceutic