Influence of sad mood induction on implicit self-esteem and its relationship with symptoms of depression and anxiety

Background and objectivesImplicit self-esteem (ISE) refers to the valence of triggered associations when the self is activated. Despite theories, previous studies often fail to observe low ISE in depression and anxiety. It is feasible that sad mood is required to activate dysfunctional self-associations. The present study tested the following hypotheses: i) ISE is lower following a sad mood induction (SMI); ii) the relationship between ISE and level of depression/anxiety symptoms is relatively strong when ISE is measured during sad mood; iii) individuals with higher levels of depression/anxiety symptoms will show a relatively large decrease in ISE following a SMI.MethodsIn this mixed-designed study, university students completed the self-esteem implicit association test (IAT) either at baseline (control condition; n = 46) or following a SMI (experimental condition; n = 49). To test the third hypothesis, a SMI and IAT were also given in the control condition. Both conditions completed self-report measures of explicit self-esteem (ESE), and symptoms of depression and anxiety.ResultsThere was no support for the first two hypotheses, but some support that symptoms of anxiety correlated with larger decreases in ISE following a SMI which partly supported the third hypothesis. This disappeared when controlling for multiple testing.LimitationsResults are limited to non-clinical participants.ConclusionsWhile ISE was robust against increases in sad mood, there was some tentative support that symptoms of anxiety were related to larger decreases in ISE following a SMI

Rapid reduction of sigma(1)-Receptor binding and F-18-FDG uptake in rat gliomas after in vivo treatment with doxorubicin

sigma-Receptors are strongly overexpressed in most rodent and human tumors and are proliferation markers. To evaluate the potential of a radiolabeled sigma(1)-ligand for therapy monitoring, we compared early changes of C-11-1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine (C-11-SA4503) binding and F-18-FDG uptake in gliomas after in vivo chemotherapy. Methods: C6 cells (2.5 x 10(6)) were subcutaneously injected into the right shoulder of male Wistar rats. After 7 cl, the tumor volume was 0.60 +/- 0.08 cm(3). Animals then received either saline or doxorubicin (8 mg/kg, intraperitoneally). One control and 1 treated rat were imaged simultaneously, 24 or 48 h after treatment, under pentobarbital anesthesia. Rodents (n = 20) were scanned first with C-11-SA4503 (25 MBq, intravenously) followed more than 100 min afterward by 18F-FDG (20 MBq, intravenously), using a dedicated small-animal PET camera (60-min protocol, tumors in the field of view). Tumor homogenates were prepared and subjected to sigma-receptor assays. The biodistribution of 18F-FDG was assessed. Results: Tumors appeared 4-5 d after inoculation and grew exponentially. No significant reduction of tumor growth was visible within 48 h after doxorubicin treatment. Both PET tracers visualized the tumors and showed reduced uptake after chemotherapy (C-11-SA4503: 26.5% +/- 6.5% at 24 h, 26.5% +/- 7.5% at 48 h; 18F-FDG: 22.6% +/- 3.2% at 24 h, 27.4% +/- 3.2% at 48 h; ex vivo F-18-FDG: 22.4% +/- 5.4% at 24 h, 31.7% +/- 12.7% at 48 h). sigma(1)-Receptor density in treated tumors was also reduced (from 172 +/- 35 to 125 +/- 28 fmol/mg of protein). Conclusion: Both C-11-SA4503 binding and 18F-FDG uptake declined in gliomas after chemotherapy. Decreased binding of C-11-SA4503 corresponded to a loss of (sigma(1)-receptors from the tumors. Changes in tracer uptake preceded the morphologic changes by at least 48 h

SMART (SiMulAtion and ReconsTruction) PET:an efficient PET simulation-reconstruction tool

Background: Positron-emission tomography (PET) simulators are frequently used for development and performance evaluation of segmentation methods or quantitative uptake metrics. To date, most PET simulation tools are based on Monte Carlo simulations, which are computationally demanding. Other analytical simulation tools lack the implementation of time of flight (TOF) or resolution modelling (RM). In this study, a fast and easy-to-use PET simulation-reconstruction package, SiMulAtion and ReconsTruction (SMART)-PET, is developed and validated, which includes both TOF and RM. SMART-PET, its documentation and instructions to calibrate the tool to a specific PET/CT system are available on Zenodo.SMART-PET allows the fast generation of 3D PET images. As input, it requires one image representing the activity distribution and one representing the corresponding CT image/attenuation map. It allows the user to adjust different parameters, such as reconstruction settings (TOF/RM), noise level or scan duration. Furthermore, a random spatial shift can be included, representing patient repositioning. To evaluate the tool, simulated images were compared with real scan data of the NEMA NU 2 image quality phantom. The scan was acquired as a 60-min list-mode scan and reconstructed with and without TOF and/or RM. For every reconstruction setting, ten statistically equivalent images, representing 30, 60, 120 and 300 s scan duration, were generated. Simulated and real-scan data were compared regarding coefficient of variation in the phantom background and activity recovery coefficients (RCs) of the spheres. Furthermore, standard deviation images of each of the ten statistically equivalent images were compared.Results: SMART-PET produces images comparable to actual phantom data. The image characteristics of simulated and real PET images varied in similar ways as function of reconstruction protocols and noise levels. The change in image noise with variation of simulated TOF settings followed the theoretically expected behaviour. RC as function of sphere size agreed within 0.3-11% between simulated and actual phantom data.Conclusions: SMART-PET allows for rapid and easy simulation of PET data. The user can change various acquisition and reconstruction settings (including RM and TOF) and noise levels. The images obtained show similar image characteristics as those seen in actual phantom data.</p

Allergenic food introduction and risk of childhood atopic diseases

Background: The role of timing and diversity of allergenic food introduction in the development of childhood allergic sensitization and atopic diseases is controversial. Objective: To examine whether timing and diversity of allergenic food introduction are associated with allergic sensitization, allergy and eczema in children until age 10 years. Materials and methods: This study among 5,202 children was performed in a population-based prospective cohort. Timing (age 6 months vs. >6 months) and diversity (0, 1, 2 and 3 foods) of allergenic food (cow’s milk, hen’s egg, peanut, tree nuts, soy and gluten) introduction were assessed by questionnaires at ages 6 and 12 months. At age 10 years, inhalant and food allergic sensitization were measured by skin prick tests, and physician-diagnosed inhalant and food allergy by questionnaire. Data on parental-reported physician-diagnosed eczema were obtained from birth until age 10 years. Results: Children introduced to gluten at age 6 months had a decreased risk of eczema (aOR (95% CI): 0.84 (0.72, 0.99)), compared with children introduced to gluten at age >6 months. However, timing of allergenic food introduction was not associated with allergic sensitization or physician-diagnosed allergy. Children introduced to 3 allergenic foods at age 6 months had a decreased risk of physician-diagnosed inhalant allergy (0.64 (0.42, 0.98)), compared with children not introduced to any allergenic food at age 6 months. However, diversity of allergenic food introduction was not associated with allergic sensitization, physician-diagnosed food allergy or eczema. Conclusion: Neither timing nor diversity of allergenic food introduction was consistently associate

Repeatability of 18 F-FDG PET radiomic features:A phantom study to explore sensitivity to image reconstruction settings, noise, and delineation method

BACKGROUND: 18 F-fluoro-2-deoxy-D-Glucose positron emission tomography (18 F-FDG PET) radiomics has the potential to guide the clinical decision making in cancer patients, but validation is required before radiomics can be implemented in the clinical setting. The aim of this study was to explore how feature space reduction and repeatability of 18 F-FDG PET radiomic features are affected by various sources of variation such as underlying data (e.g., object size and uptake), image reconstruction methods and settings, noise, discretization method, and delineation method.METHODS: The NEMA image quality phantom was scanned with various sphere-to-background ratios (SBR), simulating different activity uptakes, including spheres with low uptake, that is, SBR smaller than 1. Furthermore, images of a phantom containing 3D printed inserts reflecting realistic heterogeneity uptake patterns were acquired. Data were reconstructed using various matrix sizes, reconstruction algorithms, and scan durations (noise). For every specific reconstruction and noise level, ten statistically equal replicates were generated. The phantom inserts were delineated using CT and PET-based segmentation methods. A total of 246 radiomic features was extracted from each image dataset. Images were discretized with a fixed number of 64 bins (FBN) and a fixed bin width (FBW) of 0.25 for the high and a FBW of 0.05 for the low uptake data. In terms of feature reduction, we determined the impact of these factors on the composition of feature clusters, which were defined on the basis of Spearman's correlation matrices. To assess feature repeatability, the intraclass correlation coefficient was calculated over the ten replicates.RESULTS: In general, larger spheres with high uptake resulted in better repeatability compared to smaller low uptake spheres. In terms of repeatability, features extracted from heterogeneous phantom inserts were comparable to features extracted from bigger high uptake spheres. For example, for an EARL-compliant reconstruction, larger and smaller high uptake spheres yielded good repeatability for 32% and 30% of the features, while the heterogeneous inserts resulted in 34% repeatable features. For the low uptake spheres, this was the case for 22% and 20% of the features for bigger and smaller spheres, respectively. Images reconstructed with point-spread-function (PSF) resulted in the highest repeatability when compared with OSEM or time-of-flight, for example, 53%, 30%, and 32% of repeatable features, respectively (for unsmoothed data, discretized with FBN, 300 s scan duration). Reducing image noise (increasing scan duration and smoothing) and using CT-based segmentation for the low uptake spheres yielded improved repeatability. FBW discretization resulted in higher repeatability than FBN discretization, for example, 89% and 35% of the features, respectively (for the EARL-compliant reconstruction and larger high uptake spheres).CONCLUSION: Feature space reduction and repeatability of 18 F-FDG PET radiomic features depended on all studied factors. The high sensitivity of PET radiomic features to image quality suggests that a high level of image acquisition and preprocessing standardization is required to be used as clinical imaging biomarker.</p

Radiation Dosimetry of a Novel Adenosine A(2A) Receptor Radioligand [C-11]Preladenant Based on PET/CT Imaging and Ex Vivo Biodistribution in Rats

[C-11]Preladenant was developed as a novel adenosine A(2A) receptor PET radioligand. The aim of this study was to determine the radiation dosimetry of [C-11]preladenant and to investigate whether dosimetry estimation based on organ harvesting can be replaced by positron emission tomography (PET)/x-ray computed tomography (CT) imaging in rats. Male Wistar rats (n = 35) were i.v. injected with [C-11]preladenant. The tracer biodistribution was determined by organ harvesting at 1, 5, 15, 30, 60, and 90 min post injection. Hollow organs including the stomach, intestines, and urinary bladder were harvested with contents. In 10 rats, a 90-min dynamic PET/CT scan of the torso was acquired. Twenty volumes of interest (VOIs) were manually drawn on the PET image using the CT image of the same animal as anatomical reference. The dynamic time-activity curves were used to calculate organ residence times (RTs). Human radiation dosimetry estimates, derived from rat data, were calculated with OLINDA/EXM 1.1. PET-imaging and organ-harvesting estimated comparable organ RTs, with differences of 6-27 %, except for the lungs, pancreas, and urinary bladder, with differences of 48, 53, and 60, respectively. The critical organ was the small intestine with a dose of 25 mu Sv/MBq. The effective doses (EDs) calculated from imaging-based and organ-harvesting-derived data were 5.5 and 5.6 mu Sv/MBq, respectively, using the International Commission on Radiological Protection 60 tissue weighting factors. The ED of [C-11]preladenant (2 mSv for a 370-MBq injected dose) is comparable with other C-11-labeled PET tracers. Estimation of the radiation dosimetry of [C-11]preladenant by PET/CT imaging in rats is feasible and gives comparable results to organ harvesting, provided that small VOIs are used and the content of hollow organs is taken into account. Dosimetry by PET imaging can strongly reduce the number of laboratory animals required

The effect of induction therapy with infliximab or vedolizumab on hepcidin and iron status in patients with Inflammatory Bowel Disease

Background Differentiating absolute iron deficiency from functional iron restriction is challenging in active Inflammatory Bowel Disease (IBD). Hepcidin, the systemic iron regulator, could be the key in the diagnosis and management of absolute iron deficiency. In this study, we assessed hepcidin as a diagnostic iron deficiency marker and we explored the relationship between hepcidin, inflammation, hypoxia, and iron deficiency in patients receiving induction therapy with infliximab (IFX) or vedolizumab (VEDO). Methods 130 patients with IBD, who received induction therapy with IFX or VEDO for active disease, were included in this study. Clinical and biochemical data were extracted from medical records. Serum samples at baseline and week 6 of induction therapy were retrieved from the University Medical Center Groningen (UMCG) biobank and analysed for: hepcidin, inflammation (e.g., interleukins [IL] 6, 10, and Tumour Necrosis Factor-α [TNFα]), oxidative stress (free thiols), and hypoxia (e.g., erythropoietin [EPO], Macrophage Inflammatory Protein-3α [MIP3α]). For comparison, serum samples from 50 age- and gender-matched healthy controls were obtained from pre-donation biobank at the UMCG. Response to therapy was defined by either General Physician’s Assessment at week 14 of induction therapy, normalisation or at least a three-point decrease in clinical scores: Harvey-Bradshaw Index (HBI) for Crohn’s Disease, Simple Clinical Colitis Activity Index (SCCAI) for ulcerative colitis. Results Hepcidin correlated with ferritin and sTfR/log ferritin index [ρ = 0.74 and ρ = -0.79, respectively; P<0.001 for both markers], while inflammation- and hypoxia-associated markers showed only marginal correlations. Hepcidin accurately identified absolute iron deficiency: AUC(hepcidin) = 0.89 [95% CI: 0.82–0.95; P<0.001]. Induction with either IFX or VEDO decreased hepcidin [13.5 ng/mL vs. 9.5 ng/mL; P<0.001], ferritin [45.5 ug/L vs. 37.0 ug/L, P<0.05], and inflammatory markers at week 6, while transferrin increased [2.4 g/L vs. 2.5 g/L, P<0.001]. In total, 75.4% of patients responded to the induction therapy. Hepcidin and ferritin decreased, while transferrin increased (P<0.001 for all changes) in patients who responded to the therapy. In addition, hypoxia (EPO and MIP3α) and inflammatory markers such as faecal calprotectin, IL-6, IL-22, and TNFα improved significantly. In contrast, none of these improvements were observed in patients who did not respond to the therapy. Conclusion Hepcidin reflects iron deficiency in active IBD, but inflammation masks the severity of the deficiency. Induction therapy with either IFX or VEDO modulates hepcidin and iron indices, especially in patients who respond to the therapy