| 1. |
- Benveniste, Helene, et al.
(författare)
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Determination of Brain Interstitial Concentrations by Microdialysis
- 1989
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Ingår i: Journal of Neurochemistry. - : Wiley. - 1471-4159 .- 0022-3042. ; 52:6, s. 1741-1750
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Tidskriftsartikel (refereegranskat)abstract
- Microdialysis is an extensively used technique for the study of solutes in brain interstitial space. The method is based on collection of substances by diffusion across a dialysis membrane positioned in the brain. The outflow concentration reflects the interstitial concentration of the substance of interest, but the relationship between these two entities is at present unclear. So far, most evaluations have been based solely on calibrations in saline. This procedure is misleading, because the ease by which molecules in saline diffuse into the probe is different from that of tissue. We describe here a mathematical analysis of mass transport into the dialysis probe in tissue based on diffusion equations in complex media. The main finding is that diffusion characteristics of a given substance have to be included in the formula. These include the tortuosity factor (λ) and the extracellular volume fraction (α). We have substantiated this by studies in a welldefined complex medium (red blood cell suspensions) as well as in brain. We conclude that the traditional calculation procedure results in interstitial concentrations that are too low by a factor of λ2/α for a given compound.
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| 2. |
- Bohr, Tomas, et al.
(författare)
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The glymphatic system : Current understanding and modeling
- 2022
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Ingår i: iScience. - : Elsevier BV. - 2589-0042. ; 25:9
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Forskningsöversikt (refereegranskat)abstract
- We review theoretical and numerical models of the glymphatic system, which circulates cerebrospinal fluid and interstitial fluid around the brain, facilitating solute transport. Models enable hypothesis development and predictions of transport, with clinical applications including drug delivery, stroke, cardiac arrest, and neurodegenerative disorders like Alzheimer's disease. We sort existing models into broad categories by anatomical function: Perivascular flow, transport in brain parenchyma, interfaces to perivascular spaces, efflux routes, and links to neuronal activity. Needs and opportunities for future work are highlighted wherever possible; new models, expanded models, and novel experiments to inform models could all have tremendous value for advancing the field.
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| 3. |
- Madru, Renata, et al.
(författare)
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Simultaneous Preclinical Positron Emission Tomography-Magnetic Resonance Imaging Study of Lymphatic Drainage of Chelator-Free Cu-Labeled Nanoparticles
- 2018
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Ingår i: Cancer Biotherapy & Radiopharmaceuticals. - : Mary Ann Liebert Inc. - 1557-8852 .- 1084-9785. ; 33:6, s. 213-220
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Hybrid positron emission tomography (PET)-magnetic resonance imaging (MRI) systems have been taken in use as new clinical diagnostic tools including detection and therapy planning of cancer. To reduce the amount of contrast agents injected in patients while fully benefitting both modalities, dual-modality probes are required.MATERIAL AND METHODS: This study was first aimed at developing a hybrid PET-MRI probe by labeling superparamagnetic iron oxide nanoparticles (SPIONs) with 64Cu using a fast and chelator-free conjugation method, and second, to demonstrate the ability of the agent to target sentinel lymph nodes (SLNs) in vivo using simultaneous PET-MRI imaging.RESULTS: High labeling efficiency of 97% produced within 10-15 min was demonstrated at room temperature. 64Cu-SPIONs were chemically stable in mouse serum for 24 h and after intradermal injection in the hind paw of C57BL/6J mice, demonstrated specific accumulation in the SLN. Simultaneous PET-MRI clearly demonstrated visualization of 64Cu-SPIONs, in dynamic and static imaging sequences up to 24 h after administration.CONCLUSION: The use of a single hybrid probe and simultaneous hybrid imaging provides an efficient, complementary integration of quantitation and is expected to improve preoperative planning and intraoperative guidance of cancer treatments.
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| 4. |
- Nicholson, James, et al.
(författare)
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Leptin Levels Are Negatively Correlated with 2-Arachidonoylglycerol in the Cerebrospinal Fluid of Patients with Osteoarthritis
- 2015
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Ingår i: PLOS ONE. - : Public Library of Science (PLoS). - 1932-6203. ; 10:4
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Tidskriftsartikel (refereegranskat)abstract
- ` Background There is compelling evidence in humans that peripheral endocannabinoid signaling is disrupted in obesity. However, little is known about the corresponding central signaling. Here, we have investigated the relationship between gender, leptin, body mass index (BMI) and levels of the endocannabinoids anandamide (AEA) and 2-arachidonoylglycerol (2-AG) in the serum and cerebrospinal fluid (CSF) of primarily overweight to obese patients with osteoarthritis. Methodology/Principal Findings Patients (20 females, 15 males, age range 44-78 years, BMI range 24-42) undergoing total knee arthroplasty for end-stage osteoarthritis were recruited for the study. Endocannabinoids were quantified by liquid chromatography - mass spectrometry. AEA and 2-AG levels in the serum and CSF did not correlate with either age or BMI. However, 2-AG levels in the CSF, but not serum, correlated negatively with CSF leptin levels (Spearman's. -0.48, P=0.0076, n=30). No such correlations were observed for AEA and leptin. Conclusions/Significance In the patient sample investigated, there is a negative association between 2-AG and leptin levels in the CSF. This is consistent with pre-clinical studies in animals, demonstrating that leptin controls the levels of hypothalamic endocannabinoids that regulate feeding behavior.
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