236 research outputs found

    Endogenous circatidal rhythm in the Manila clam Ruditapes philippinarum (Bivalvia: Veneridae)

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    Manila clams, Ruditapes philippinarum, removed from their natural environment and maintained for 9 weeks in continuously immersed conditions exhibited a clear endogenous circatidal rhythm in oxygen consumption. The clams exhibited a semidiurnal rhythmicity in oxygen consumption after showing a diurnal pattern in the first few days (5 to 7 d) of the experiment. The results of the present study indicate that activity rhythms of clams are controlled not only by exogenous factors, but also by an endogenous circatidal periodicity

    TotalSegmentator: robust segmentation of 104 anatomical structures in CT images

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    We present a deep learning segmentation model that can automatically and robustly segment all major anatomical structures in body CT images. In this retrospective study, 1204 CT examinations (from the years 2012, 2016, and 2020) were used to segment 104 anatomical structures (27 organs, 59 bones, 10 muscles, 8 vessels) relevant for use cases such as organ volumetry, disease characterization, and surgical or radiotherapy planning. The CT images were randomly sampled from routine clinical studies and thus represent a real-world dataset (different ages, pathologies, scanners, body parts, sequences, and sites). The authors trained an nnU-Net segmentation algorithm on this dataset and calculated Dice similarity coefficients (Dice) to evaluate the model's performance. The trained algorithm was applied to a second dataset of 4004 whole-body CT examinations to investigate age dependent volume and attenuation changes. The proposed model showed a high Dice score (0.943) on the test set, which included a wide range of clinical data with major pathologies. The model significantly outperformed another publicly available segmentation model on a separate dataset (Dice score, 0.932 versus 0.871, respectively). The aging study demonstrated significant correlations between age and volume and mean attenuation for a variety of organ groups (e.g., age and aortic volume; age and mean attenuation of the autochthonous dorsal musculature). The developed model enables robust and accurate segmentation of 104 anatomical structures. The annotated dataset (https://doi.org/10.5281/zenodo.6802613) and toolkit (https://www.github.com/wasserth/TotalSegmentator) are publicly available.Comment: Accepted at Radiology: Artificial Intelligenc

    Trends in biomass, density and diversity of North Sea macrofauna

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    Total biomass and biomass of large taxonomic groups (polychaetes, molluscs, crustaceans, echinoderms) and species diversity of the macrofauna were determined for almost 200 North Sea stations sampled synoptically by seven vessels during Spring 1986 and for 120 additional stations sampled in earlier years by the Marine Laboratory in Aberdeen. There exists a clear and significant decreasing trend in biomass with latitude, both in total biomass and for the different taxonomic groups. Apart from latitude, sediment composition and chlorophyll a content of the sediment also infuence total biomass and biomass of most groups significantly. Biomass increases consistently in finer sediments and sediments with a higher chlorophyll a content. The same trends are found for the results within laboratories. Some interaction exists, indicating weak laboratory and zonal effects. Diversity, as measured by Hill's diversity index N1 = (exp H′) shows a clear and significant trend with latitude. Towards the north of the North Sea diversity increases considerably. The trend is also found for laboratories separately and is everywhere equally strong. Also longitude and depth show an effect on diversity. Sediment variables have no clear influence on diversity. Other diversity measures show the same trend but are more variable than N1,. Total density tends to increase towards the north, but sediment related variables have a larger influence. Mean individual weight becomes considerably smaller towards the northern part of the North Sea

    Isosorbide Mononitrate and Cilostazol Treatment in Patients With Symptomatic Cerebral Small Vessel Disease: The Lacunar Intervention Trial-2 (LACI-2) Randomized Clinical Trial

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    IMPORTANCE: Cerebral small vessel disease (cSVD) is a common cause of stroke (lacunar stroke), is the most common cause of vascular cognitive impairment, and impairs mobility and mood but has no specific treatment. OBJECTIVE: To test the feasibility, drug tolerability, safety, and effects of 1-year isosorbide mononitrate (ISMN) and cilostazol treatment on vascular, functional, and cognitive outcomes in patients with lacunar stroke. DESIGN, SETTING, AND PARTICIPANTS: The Lacunar Intervention Trial-2 (LACI-2) was an investigator-initiated, open-label, blinded end-point, randomized clinical trial with a 2 × 2 factorial design. The trial aimed to recruit 400 participants from 26 UK hospital stroke centers between February 5, 2018, and May 31, 2021, with 12-month follow-up. Included participants had clinical lacunar ischemic stroke, were independent, were aged older than 30 years, had compatible brain imaging findings, had capacity to consent, and had no contraindications to (or indications for) the study drugs. Data analysis was performed on August 12, 2022. INTERVENTIONS: All patients received guideline stroke prevention treatment and were randomized to ISMN (40-60 mg/d), cilostazol (200 mg/d), ISMN-cilostazol (40-60 and 200 mg/d, respectively), or no study drug. MAIN OUTCOMES: The primary outcome was recruitment feasibility, including retention at 12 months. Secondary outcomes were safety (death), efficacy (composite of vascular events, dependence, cognition, and death), drug adherence, tolerability, recurrent stroke, dependence, cognitive impairment, quality of life (QOL), and hemorrhage. RESULTS: Of the 400 participants planned for this trial, 363 (90.8%) were recruited. Their median age was 64 (IQR, 56.0-72.0) years; 251 (69.1%) were men. The median time between stroke and randomization was 79 (IQR, 27.0-244.0) days. A total of 358 patients (98.6%) were retained in the study at 12 months, with 257 of 272 (94.5%) taking 50% or more of the allocated drug. Compared with those participants not receiving that particular drug, neither ISMN (adjusted hazard ratio [aHR], 0.80 [95% CI, 0.59 to 1.09]; P = .16) nor cilostazol (aHR, 0.77 [95% CI, 0.57 to 1.05]; P = .10) alone reduced the composite outcome in 297 patients. Isosorbide mononitrate reduced recurrent stroke in 353 patients (adjusted odds ratio [aOR], 0.23 [95% CI, 0.07 to 0.74]; P = .01) and cognitive impairment in 308 patients (aOR, 0.55 [95% CI, 0.36 to 0.86]; P = .008). Cilostazol reduced dependence in 320 patients (aHR, 0.31 [95% CI, 0.14 to 0.72]; P = .006). Combination ISMN-cilostazol reduced the composite (aHR, 0.58 [95% CI, 0.36 to 0.92]; P = .02), dependence (aOR, 0.14 [95% CI, 0.03 to 0.59]; P = .008), and any cognitive impairment (aOR, 0.44 [95% CI, 0.23 to 0.85]; P = .02) and improved QOL (adjusted mean difference, 0.10 [95% CI, 0.03 to 0.17]; P = .005) in 153 patients. There were no safety concerns. CONCLUSIONS AND RELEVANCE: These results show that the LACI-2 trial was feasible and ISMN and cilostazol were well tolerated and safe. These agents may reduce recurrent stroke, dependence, and cognitive impairment after lacunar stroke, and they could prevent other adverse outcomes in cSVD. Therefore, both agents should be tested in large phase 3 trials. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03451591

    Multi organ assessment of compensated cirrhosis patients using quantitative magnetic resonance imaging

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    Background and Aims: Advancing liver disease results in deleterious changes in a number of critical organs. The ability to measure structure, blood flow and tissue perfusion within multiple organs in a single scan has implications for determining the balance of benefit versus harm for therapies. Our aim was to establish the feasibility of Magnetic Resonance Imaging to assess changes in compensated cirrhosis (CC), and relate this to disease severity and future liver related outcomes (LROs). Methods: 60 CC patients, 40 healthy volunteers and 7 decompensated cirrhotics were recruited. In a single scan session, MRI measures comprised phase-contrast MRI vessel blood flow, arterial spin labelling tissue perfusion, T1 longitudinal relaxation time and volume assessment of liver, spleen and kidneys, heart rate and cardiac index. We explore MRI parameters with disease severity and differences in baseline MRI parameters in those 11 (18%) of CC patients who had future LROs. Results: In the liver compositional changes were reflected by increased T1 in progressive disease (p<0.001) and an increase in liver volume in CC (p=0.006), with associated progressive reduction in liver (p < 0.001) and splenic (p<0.001) perfusion. A significant reduction in renal cortex T1 and increase in cardiac index and superior mesenteric arterial (SMA) blood flow was seen with increasing disease severity. Baseline liver T1 (p=0.01) and perfusion (p< 0.01), and renal cortex T1 (p<0.01) were significantly different in CC patients who subsequently developed negative LROs. Conclusions: MRI allows the contemporaneous assessment of organs in liver cirrhosis in a single scan without the requirement of contrast agent. MRI parameters of liver T1, renal T1, hepatic and splenic perfusion, and SMA blood flow were related to risk of LROs

    Automatic segmentation of myocardium from black-blood MR images using entropy and local neighborhood information.

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    By using entropy and local neighborhood information, we present in this study a robust adaptive Gaussian regularizing Chan-Vese (CV) model to segment the myocardium from magnetic resonance images with intensity inhomogeneity. By utilizing the circular Hough transformation (CHT) our model is able to detect epicardial and endocardial contours of the left ventricle (LV) as circles automatically, and the circles are used as the initialization. In the cost functional of our model, the interior and exterior energies are weighted by the entropy to improve the robustness of the evolving curve. Local neighborhood information is used to evolve the level set function to reduce the impact of the heterogeneity inside the regions and to improve the segmentation accuracy. An adaptive window is utilized to reduce the sensitivity to initialization. The Gaussian kernel is used to regularize the level set function, which can not only ensure the smoothness and stability of the level set function, but also eliminate the traditional Euclidean length term and re-initialization. Extensive validation of the proposed method on patient data demonstrates its superior performance over other state-of-the-art methods

    In Vivo Near-Infrared Imaging of Fibrin Deposition in Thromboembolic Stroke in Mice

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    imaging of activated factor XIII (FXIIIa), an important mediator of thrombosis or fibrinolytic resistance. The present study was to investigate the fibrin deposition in a thromboembolic stroke mice model by FXIIIa–targeted near-infrared fluorescence (NIRF) imaging., which were correlated with histology after animal euthanasia. NIRF images and lesion volume.Non-invasive detection of fibrin deposition in ischemic mouse brain using NIRF imaging is feasible and this technique may provide an in vivo experimental tool in studying the role of fibrin in stroke
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