153 research outputs found

    Continuous monitoring of PbrO2 in patients with severe head injury

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    The first Chapter is an introduction to neurotraumatology. The incidence of severe head injury, and its financial burden to society is described. General information is provided on the currently used monitoring modalities in patients with severe head injury. Finally a description is given of the polarographic monitoring method for measuring oxygen tension in brain tissue (PbrO2) used in our studies. The study questions are specified focussing on clinical applicability of PbrO2 measurements in TBI and interpretation of findings. In Chapter 2 preliminary experience with brain tissue PO2 (PbrO2) monitoring in a group of 22 patients with a severe head injury is described. PbrO2 was measured with a polarographic microcatheter. For introduction of the catheter a specially devised intracranial bolt was used. Measurements started as soon as possible after the injury and the study protocol specified an observation period of a maximum of 120 hours post trauma. The rationale for this time period was that during the initial period after trauma low Cerebral Blood Flow (CBF) values have been reported with Xe CT studies, and that vasospasm mostly occurs before day 5 after injury. Both potential ischemic phenomena are covered by the observation period chosen. During the observation period two provocation tests were included in the study protocol performed on a dayly basis. Firstly, an O2 provocation test, by increasing the fraction of inspired oxygen stepwise to 1.0, and secondly a carbon dioxide reactivity test performed by increasing the respiratory minute volume of the patient by 20%. The observation period was preliminary terminated by early death or if clinical improvement of the patient occurred to an extent that ICP monitoring was no longer considered necessary. PbrO2 monitoring was started on average 7.0 hours after trauma with a mean duration of 74.3 hours. The chapter provides an extensive description of all phenomena observed. No complications were seen related to the PbrO2 catheter. The catheters showed a zero display error of 1.2 ± 0.8 mmHg and a sensitivity drift of 9.7 ± 5.3% after the measurement period. The first approach to analyse the PbrO2 value was to average all PO2 values according to the time after injury. Using this method of analysis we observed low average values during the initial 24 hours after injury, increasing toward a peak value during the second 24 hours reaching a plateau value after 36-48 hours after injury. Beyond this time period mean PbrO2 showed no further changes

    Implementation of a mobile 0.15-T intraoperative MR system in pediatric neuro-oncological surgery: feasibility and correlation with early postoperative high-field strength MRI

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    INTRODUCTION: We analyze our preliminary experience using the PoleStar N20 mobile intraoperative MR (iMR) system as an adjunct for pediatric brain tumor resection. METHODS: We analyzed 11 resections in nine children between 1 month and 17 years old. After resection, we acquired iMR scans to detect residual tumor and update neuronavigation. We compared final iMR interpretation by the neurosurgeon with early postoperative MR interpretation by a neuroradiologist. RESULTS: Patient positioning was straightforward, and image quality (T1 7-min 4-mm sequences) sufficient in all cases. In five cases, contrast enhancement suspect for residual tumor was noted on initial postresection iMR images. In one case, a slight discrepancy with postoperative imaging after 3 months was no longer visible after 1 year. No serious perioperative adverse events related to the PoleStar N20 were encountered, except for transient shoulder pain in two. CONCLUSIONS: Using the PoleStar N20 iMR system is technically feasible and safe for both supra- and infratentorial tumor resections in children of all ages. Their small head and shoulders favor positioning in the magnet bore and allow the field of view to cover more than the area of primary interest, e.g., the ventricles in an infratentorial case. Standard surgical equipment may be used without significant limitations. In this series, the use of iMR leads to an increased extent of tumor resection in 45 % of cases. Correlation between iMR and early postoperative MR is excellent, provided image quality is optimal and interpretation is carefully done by someone sufficiently familiar with the system

    A novel CCR2 antagonist inhibits atherogenesis in apoE deficient mice by achieving high receptor occupancy

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    CC Chemokine Receptor 2 (CCR2) and its endogenous ligand CCL2 are involved in a number of diseases, including atherosclerosis. Several CCR2 antagonists have been developed as potential therapeutic agents, however their in vivo clinical efficacy was limited. In this report, we aimed to determine whether 15a, an antagonist with a long residence time on the human CCR2, is effective in inhibiting the development of atherosclerosis in a mouse disease model. First, radioligand binding assays were performed to determine affinity and binding kinetics of 15a on murine CCR2. To assess the in vivo efficacy, western-type diet fed apoE-/- mice were treated daily with 15a or vehicle as control. Treatment with 15a reduced the amount of circulating CCR2+ monocytes and the size of the atherosclerotic plaques in both the carotid artery and the aortic root. We then showed that the long pharmacokinetic half-life of 15a combined with the high drug concentrations ensured prolonged CCR2 occupancy. These data render 15a a promising compound for drug development and confirms high receptor occupancy as a key parameter when targeting chemokine receptors

    Defective Autophagy in T Cells Impairs the Development of Diet-Induced Hepatic Steatosis and Atherosclerosis

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    Macroautophagy (or autophagy) is a conserved cellular process in which cytoplasmic cargo is targeted for lysosomal degradation. Autophagy is crucial for the functional integrity of different subsets of T cells in various developmental stages. Since atherosclerosis is an inflammatory disease of the vessel wall which is partly characterized by T cell mediated autoimmunity, we investigated how advanced atherosclerotic lesions develop in mice with T cells that lack autophagy-related protein 7 (Atg7), a protein required for functional autophagy. Mice with a T cell-specific knock-out of Atg7 (Lck-Cre Atg7f/f) had a diminished naïve CD4+ and CD8+ T cell compartment in the spleen and mediastinal lymph node as compared to littermate controls (Atg7f/f). Lck-Cre Atg7f/f and Atg7f/f mice were injected intravenously with rAAV2/8-D377Y-mPCSK9 and fed a Western-type diet to induce atherosclerosis. While Lck-Cre Atg7f/f mice had equal serum Proprotein Convertase Subtilisin/Kexin type 9 levels as compared to Atg7f/f mice, serum cholesterol levels were significantly diminished in Lck-Cre Atg7f/f mice. Histological analysis of the liver revealed less steatosis, and liver gene expression profiling showed decreased expression of genes associated with hepatic steatosis in Lck-Cre Atg7f/f mice as compared to Atg7f/f mice. The level of hepatic CD4+ and CD8+ T cells was greatly diminished but both CD4+ and CD8+ T cells showed a relative increase in their IFNγ and IL-17 production upon Atg7 deficiency. Atg7 deficiency furthermore reduced the hepatic NKT cell population which was decreased to < 0.1% of the lymphocyte population. Interestingly, T cell-specific knock-out of Atg7 decreased the mean atherosclerotic lesion size in the tri-valve area by over 50%. Taken together, T cell-specific deficiency of Atg7 resulted in a decrease in hepatic steatosis and limited inflammatory potency in the (naïve) T cell compartment in peripheral lymphoid tissues, which was associated with a strong reduction in experimental atherosclerosis

    First effective mHealth nutrition and lifestyle coaching program for subfertile couples undergoing in vitro fertilization treatment:a single-blinded multicenter randomized controlled trial

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    Objective: To study compliance and effectiveness of the mHealth nutrition and lifestyle coaching program Smarter Pregnancy in couples undergoing in vitro fertilization (IVF) treatment with or without intracytoplasmic sperm injection (ICSI). Design: Multicenter, single-blinded, randomized controlled trial, conducted from July 2014 to March 2017. Setting: IVF clinics. Patient(s): A total of 626 women undergoing IVF treatment with or without ICSI and 222 male partners. Interventions(s): Couples were randomly assigned to the light (control group) or regular (intervention group) Smarter Pregnancy program. Both groups filled out a baseline screening questionnaire on nutrition and lifestyle behaviors, and the intervention group received coaching tailored to inadequate behaviors during the 24-week period. Main Outcome Measure(s): Difference in improvement of a composite dietary and lifestyle risk score for the intake of vegetables, fruits, folic acid supplements, smoking, and alcohol use after 24 weeks of the program. Result(s): Compared with control subjects, women and men in the intervention group showed a significantly larger improvement of inadequate nutrition behaviors after 24 weeks of coaching. At the same time, the women also showed a significantly larger improvement of inadequate lifestyle behaviors. Conclusion(s): The mHealth coaching program Smarter Pregnancy is effective and improves the most important nutritional and lifestyle behaviors among couples undergoing IVF/ICSI treatment. International multicenter randomized trials are recommended to study the effect of using Smarter Pregnancy on pregnancy, live birth, and neonatal outcome. ((C)2020 by American Society for Reproductive Medicine.)y

    An observational study of quality of motion in the aging cervical spine: sequence of segmental contributions in dynamic fluoroscopy recordings.

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    BACKGROUND: The term 'physiological motion of the spine' is commonly used although no proper definition exists. Previous work has revealed a consistent sequence of cervical segmental contributions in 80-90% of young healthy individuals. Age has been shown to be associated with a decreased quantity of motion. Therefore, it is of interest to study whether this sequence persists throughout aging. The aim of this prospective cohort study is to investigate if the consistent sequence of cervical segmental contributions in young asymptomatic individuals remains present in elderly asymptomatic individuals. METHODS: In this prospective cohort study, dynamic flexion to extension cinematographic recordings of the cervical spine were made in asymptomatic individuals aged 55-70 years old. Individuals without neck pain and without severe degenerative changes were included. Two recordings were made in each individual with a 2-to-4-week interval (T1 and T2). Segmental rotation of each individual segment between C4 and C7 was calculated to determine the sequence of segmental contributions. Secondary outcomes were segmental range of motion (sRoM) and sagittal alignment. RESULTS: Ten individuals, with an average age of 61 years, were included. The predefined consistent sequence of segmental contributions was found in 10% of the individuals at T1 and 0% at T2. sRoM and total range of motion (tRoM) were low in all participants. There was no statistically significant correlation between sagittal alignment, degeneration and sRoM in the respective segments, nor between cervical lordosis and tRoM. CONCLUSIONS: This study shows that aging is associated with loss of the consistent motion pattern that was observed in young asymptomatic individuals. The altered contribution of the cervical segments during extension did not appear to be correlated to the degree of degeneration or sagittal alignment. Trial registration clinicaltrials.gov NCT04222777, registered 10.01.2020

    Intraoperative magnetic resonance imaging versus standard neuronavigation for the neurosurgical treatment of glioblastoma: A randomized controlled trial.

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    BACKGROUND: Although the added value of increasing extent of glioblastoma resection is still debated, multiple technologies can assist neurosurgeons in attempting to achieve this goal. Intraoperative magnetic resonance imaging (iMRI) might be helpful in this context, but to date only one randomized trial exists. METHODS: We included 14 adults with a supratentorial tumor suspect for glioblastoma and an indication for gross total resection in this randomized controlled trial of which the interim analysis is presented here. Participants were assigned to either ultra-low-field strength iMRI-guided surgery (0.15 Tesla) or to conventional neuronavigation-guided surgery (cNN). Primary endpoint was residual tumor volume (RTV) percentage. Secondary endpoints were clinical performance, health-related quality of life (HRQOL) and survival. RESULTS: Median RTV in the cNN group is 6.5% with an interquartile range of 2.5-14.75%. Median RTV in the iMRI group is 13% with an interquartile range of 3.75-27.75%. A Mann-Whitney test showed no statistically significant difference between these groups (P =0.28). Median survival in the cNN group is 472 days, with an interquartile range of 244-619 days. Median survival in the iMRI group is 396 days, with an interquartile range of 191-599 days (P =0.81). Clinical performance did not differ either. For HRQOL only descriptive statistics were applied due to a limited sample size. CONCLUSION: This interim analysis of a randomized trial on iMRI-guided glioblastoma resection compared with cNN-guided glioblastoma resection does not show an advantage with respect to extent of resection, clinical performance, and survival for the iMRI group. Ultra-low-field strength iMRI does not seem to be cost-effective compared with cNN, although the lack of a valid endpoint for neurosurgical studies evaluating extent of glioblastoma resection is a limitation of our study and previous volumetry-based studies on this topic.Peer reviewe

    Diet-induced dyslipidemia induces metabolic and migratory adaptations in regulatory T cells

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    A hallmark of advanced atherosclerosis is inadequate immunosuppression by regulatory T(Treg) cells inside atherosclerotic lesions. Dyslipidemia has been suggested to alter Treg cellmigration by affecting the expression of specific membrane proteins, thereby decreasing Treg cellmigration towards atherosclerotic lesions. Besides membrane proteins, cellular metabolism has beenshown to be a crucial factor in Treg cell migration. We aimed to determine whether dyslipidemiacontributes to altered migration of Treg cells, in part, by affecting cellular metabolism.Dyslipidemia was induced by feeding Ldlr-/- mice a Western-type diet for 16-20weeks and intrinsic changes in Treg cells affecting their migration and metabolism were examined.Dyslipidemia was associated with altered mTORC2 signaling in Treg cells, decreased expression ofmembrane proteins involved in migration, including CD62L, CCR7 and S1Pr1, and decreased Tregcell migration towards lymph nodes. Furthermore, we discovered that diet-induced dyslipidemiainhibited mTORC1 signaling, induced PPARδ activation and increased fatty acid (FA) oxidation inTreg cells. Moreover, mass-spectrometry analysis of serum from Ldlr-/- mice with normolipidemia ordyslipidemia showed increases in multiple PPARδ ligands during dyslipidemia. Treatment with asynthetic PPARδ agonist increased the migratory capacity of Treg cells in vitro and in vivo in an FAoxidation dependent manner. Furthermore, diet-induced dyslipidemia actually enhanced Treg cellmigration into the inflamed peritoneum and into atherosclerotic lesions in vitro.Altogether, our findings implicate that dyslipidemia does not contribute toatherosclerosis by impairing Treg cell migration as dyslipidemia associated with an effector-likemigratory phenotype in Treg cells.Analytical BioScience
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