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142 results on '"Sneve, M."'

1. Developing blood-brain barrier arterial spin labelling as a non-invasive early biomarker of Alzheimer’s disease (DEBBIE-AD): a prospective observational multicohort study protocol

Author

Padrela, B., Mahroo, A., Tee, M., Sneve, M. H., Moyaert, P., Geier, O., Kuijer, J. P. A., Beun, S., Nordhøy, W., David Zhu, Y., Buck, M. A., Hoinkiss, D. C., Konstandin, S., Huber, J., Wiersinga, J., Rikken, R., Leeuw, D., Grydeland, H., Tippett, L., Cawston, E. E., Ozturk-Isik, E., Linn, J., Brandt, M., Tijms, B. M., Giessen, E. M., Muller, M., Fjell, A., Walhovd, K., Bjørnerud, A., Pålhaugen, L., Selnes, P., Clement, P., Achten, E., Anazodo, U., Barkhof, F., Hilal, S., Fladby, T., Eickel, K., Morgan, C., Thomas, D. L., (0000-0002-3201-6002) Petr, J., Günther, M., Mutsaerts, H. J. M. M., Padrela, B., Mahroo, A., Tee, M., Sneve, M. H., Moyaert, P., Geier, O., Kuijer, J. P. A., Beun, S., Nordhøy, W., David Zhu, Y., Buck, M. A., Hoinkiss, D. C., Konstandin, S., Huber, J., Wiersinga, J., Rikken, R., Leeuw, D., Grydeland, H., Tippett, L., Cawston, E. E., Ozturk-Isik, E., Linn, J., Brandt, M., Tijms, B. M., Giessen, E. M., Muller, M., Fjell, A., Walhovd, K., Bjørnerud, A., Pålhaugen, L., Selnes, P., Clement, P., Achten, E., Anazodo, U., Barkhof, F., Hilal, S., Fladby, T., Eickel, K., Morgan, C., Thomas, D. L., (0000-0002-3201-6002) Petr, J., Günther, M., and Mutsaerts, H. J. M. M.

Abstract

Introduction Loss of blood-brain barrier (BBB) integrity is hypothesised to be one of the earliest microvascular signs of Alzheimer’s disease (AD). Existing BBB integrity imaging methods involve contrast agents or ionising radiation, and pose limitations in terms of cost and logistics. Arterial spin labelling (ASL) perfusion MRI has been recently adapted to map the BBB permeability non-invasively. The DEveloping BBB-ASL as a non-Invasive Early biomarker (DEBBIE) consortium aims to develop this modified ASL-MRI technique for patient-specific and robust BBB permeability assessments. This article outlines the study design of the DEBBIE cohorts focused on investigating the potential of BBB-ASL as an early biomarker for AD (DEBBIE-AD). Methods and analysis DEBBIE-AD consists of a multicohort study enrolling participants with subjective cognitive decline, mild cognitive impairment and AD, as well as age-matched healthy controls, from 13 cohorts. The precision and accuracy of BBB-ASL will be evaluated in healthy participants. The clinical value of BBB-ASL will be evaluated by comparing results with both established and novel AD biomarkers. The DEBBIE-AD study aims to provide evidence of the ability of BBB-ASL to measure BBB permeability and demonstrate its utility in AD and ADrelated pathologies. Ethics and dissemination Ethics approval was obtained for 10 cohorts, and is pending for 3 cohorts. The results of the main trial and each of the secondary endpoints will be submitted for publication in a peer-reviewed journal.

Published
2024

2. Further development and application of a method for assessing radionuclide surface activity distribution and source location based on measurements of ambient dose equivalent rate

Author

Chizhov, K, primary, Bragin, Yu, additional, Sneve, M K, additional, Shandala, N, additional, Siegien, K, additional, Smith, G M, additional, Ksenofontov, A, additional, Kryanev, A, additional, Tesnov, I, additional, Koukhta, B, additional, Shimansky, Yu, additional, Goncharenko, G, additional, Drozdovitch, V, additional, and Kryuchkov, V, additional

Published
2023
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4. Blood-brain barrier permeability changes over the lifespan

Author

Padrela, B., Sneve, M. H., Zelhorst, S., Tee, M., Mahroo, A., Kuijer, J., Walhovd, K., Konstandin, S., Eickel, K., Barkhof, F., Hilal, S., Günther, M., Mutsaerts, H. J. M. M., (0000-0002-3201-6002) Petr, J., Padrela, B., Sneve, M. H., Zelhorst, S., Tee, M., Mahroo, A., Kuijer, J., Walhovd, K., Konstandin, S., Eickel, K., Barkhof, F., Hilal, S., Günther, M., Mutsaerts, H. J. M. M., and (0000-0002-3201-6002) Petr, J.

Abstract

Blood-brain-barrier (BBB) dysfunction is a hallmark of aging-related disorders, including cerebral small vessel disease and Alzheimer’s disease. An emerging biomarker of BBB dysfunction is time of exchange (Tex) of water across the BBB as measured by multi-echo arterial spin labeling MRI. We evaluated Tex across the age spectrum in 40 adults from two cohorts of healthy controls, and demonstrated that Tex is higher in gray than in white matter, higher in females than in males, and that Tex decreases with age. These findings suggest that BBB permeability changes over the lifespan can be investigated using arterial spin labeling approaches.

Published
2023

5. DEveloping Blood-Brain barrier arterial spin labeling as a non-Invasive Early biomarker (DEBBIE)

Author

Padrela, B., Tee, M., Sneve, M., Mahroo, A., Geier, O., Thomas, D., Morgan, C., Moyaert, P., Ozturk, E., Nordhøy, W., Pålhaugen, L., Linn, J., Selnes, P., Eickel, K., Konstandin, S., Kuijer, J., Hoinkiss, D., Breutigam, N., Buck, M., Achten, R., Barkhof, F., Hilal, S., Fladby, T., Anazodo, U., (0000-0002-3201-6002) Petr, J., Mutsaerts, H. J. M. M., Günther, M., Padrela, B., Tee, M., Sneve, M., Mahroo, A., Geier, O., Thomas, D., Morgan, C., Moyaert, P., Ozturk, E., Nordhøy, W., Pålhaugen, L., Linn, J., Selnes, P., Eickel, K., Konstandin, S., Kuijer, J., Hoinkiss, D., Breutigam, N., Buck, M., Achten, R., Barkhof, F., Hilal, S., Fladby, T., Anazodo, U., (0000-0002-3201-6002) Petr, J., Mutsaerts, H. J. M. M., and Günther, M.

Abstract

One of the earliest signs of Alzheimer’s disease (AD) is the loss of blood-brain barrier (BBB) integrity. Arterial spin labeling (ASL) MRI is a non-invasive way to measure perfusion and several other hemodynamic and physiological parameters, including vascular permeability. The DEveloping BBB-ASL as non-Invasive Early biomarker (DEBBIE) consortium aims to develop and integrate innovative techniques to allow robust BBB permeability assessments by ASL to develop a sensitive, non-invasive, and early biomarker for AD and related dementias. This work summarizes our planned efforts to develop and establish an MRI-based BBB permeability biomarker.

Published
2023

6. DEveloping BBB-ASL as non-Invasive Early biomarker of Alzheimer’s Disease (DEBBIE-AD): Study design

Author

Padrela, B. E., Mahroo, A., Tee, M., Sneve, M. H., Moyaert, P., Geier, O., Kuijer, J. P. A., Beun, S., Nordhøy, W., Zhu, Y. D., Buck, M. A., Hoinkiss, D. C., Konstandin, S., Huber, J., Wiersinga, J., Rikken, R., Leeuw, D., Grydeland, H., Tippett, L., Cawston, E. E., Ozturk-Isik, E., Linn, J., Brandt, M., Tijms, B., Giessen, E., Muller, M., Fjell, A. M., Walhovd, K. B., Pålhaugen, L., Selnes, P., Clement, P., Achten, E., Anazodo, U., Barkhof, F., Hilal, S., Fladby, T., Eickel, K., Morgan, C., Thomas, D. L., (0000-0002-3201-6002) Petr, J., Günther, M., Mutsaerts, H. J. M. M., Padrela, B. E., Mahroo, A., Tee, M., Sneve, M. H., Moyaert, P., Geier, O., Kuijer, J. P. A., Beun, S., Nordhøy, W., Zhu, Y. D., Buck, M. A., Hoinkiss, D. C., Konstandin, S., Huber, J., Wiersinga, J., Rikken, R., Leeuw, D., Grydeland, H., Tippett, L., Cawston, E. E., Ozturk-Isik, E., Linn, J., Brandt, M., Tijms, B., Giessen, E., Muller, M., Fjell, A. M., Walhovd, K. B., Pålhaugen, L., Selnes, P., Clement, P., Achten, E., Anazodo, U., Barkhof, F., Hilal, S., Fladby, T., Eickel, K., Morgan, C., Thomas, D. L., (0000-0002-3201-6002) Petr, J., Günther, M., and Mutsaerts, H. J. M. M.

Abstract

Introduction: Loss of blood-brain barrier (BBB) integrity is hypothesized to be one of the earliest microvascular signs of Alzheimer’s disease (AD). Arterial spin labeling (ASL) perfusion MRI has recently been adapted to map the BBB permeability non-invasively. This article outlines the study design of the DEveloping BBB-ASL as a non-Invasive Early biomarker (DEBBIE) consortium, focused on investigating the potential of BBB-ASL as an early biomarker for AD (DEBBIE-AD). Methods: DEBBIE-AD consists of 13 cohorts enrolling participants from subjective cognitive decline to AD, as well as healthy controls across the lifespan. The reproducibility and accuracy of BBB-ASL will be evaluated in healthy participants, and its clinical value will be evaluated with both established and novel AD biomarkers. Expected endpoints: DEBBIE-AD aims to provide evidence on the ability of BBB-ASL to measure BBB permeability and demonstrate its utility in AD-related pathologies, which may provide new targets for treatment.

Published
2023

7. Tracing the development and lifespan change of population-level structural asymmetry in the cerebral cortex

Author

Roe, J., Vidal-Piñeiro, D., Amlien, I., Pan, M., Sneve, M., Thiebaut de Schotten, M., Friedrich, P., Sha, Z., Francks, C., Eilertsen, E., Wang, Y., Walhovd, K., Fjell, A., and Westerhausen, R.

Abstract

Cortical asymmetry is a ubiquitous feature of brain organization that is altered in neurodevelopmental disorders and aging. Achieving consensus on cortical asymmetries in humans is necessary to uncover the genetic-developmental mechanisms that shape them and factors moderating cortical lateralization. Here, we delineate population-level asymmetry in cortical thickness and surface area vertex-wise in 7 datasets and chart asymmetry trajectories across life (4-89 years; observations = 3937; 70% longitudinal). We reveal asymmetry interrelationships, heritability, and test associations in UK Biobank (N=∼37,500). Cortical asymmetry was robust across datasets. Whereas areal asymmetry is predominantly stable across life, thickness asymmetry grows in development and declines in aging. Areal asymmetry correlates in specific regions, whereas thickness asymmetry is globally interrelated across cortex and suggests high directional variability in global thickness lateralization. Areal asymmetry is moderately heritable (max h2SNP ∼19%), and phenotypic correlations are reflected by high genetic correlations, whereas heritability of thickness asymmetry is low. Finally, we detected an asymmetry association with cognition and confirm recently-reported handedness links. Results suggest areal asymmetry is developmentally stable and arises in early life, whereas developmental changes in thickness asymmetry may lead to directional variability of global thickness lateralization. Our results bear enough reproducibility to serve as a standard for future brain asymmetry studies.

Published
2023

14. The development and application of a method for assessing radionuclide surface contamination density based on measurements of ambient dose equivalent rate

Author

Konstantin Chizhov, A Kryanev, A. Kosnikov, Siegien K, A Ksenofontov, Chumak, Mark N-K, A Krasnoschekov, Drozdovitch, Sneve M K, Bragin Yu, Kryuchkov, Tesnov I, N. K. Shandala, Szöke I, and Smith G M

Subjects
Radioisotopes, Radionuclide, Equivalent dose, Detector, Public Health, Environmental and Occupational Health, General Medicine, Fredholm integral equation, Radiation Dosage, Regression, 030218 nuclear medicine & medical imaging, Tikhonov regularization, 03 medical and health sciences, symbols.namesake, 0302 clinical medicine, 030220 oncology & carcinogenesis, Radioactive contamination, symbols, Environmental science, Stage (hydrology), Environmental Pollution, Radiometry, Waste Management and Disposal, Algorithm
Abstract

This article presents a method for assessing the radionuclide surface contamination density (SCD) on open sites and in premises of a radiation hazardous facility based on measurements of the ambient dose equivalent rate (ADER). The method is intended for use at the initial stage of the assessment of the radiation environment at facilities. The assessed SCD at a given location on the surface can differ from the directly measured SCD at that location, since sources located on the surface and distributed by the depth contribute to the ADER value. The method makes it possible to estimate SCD with reasonable accuracy without increasing the number of measurements, and thus avoid additional occupational exposure and the use of additional resources. SCD and ADER as spatial variables have different support of measurement data. For ADER, measured at a height of 1 m, the support of measurement data can be taken to be a circle in the centre of which a gamma-ray detector is located, with a radius of several tens of meters. In contrast, SCD has the support of measurement data, close to the overall dimensions of the beta detector (100 cm2). To solve the problem of SCD calculation on the basis of ADER measurements, the method of conversion coefficients (MCC) is usually applied, based on the use of conversion factors; however, this method provides an adequate estimate only under conditions of an SCD with low gradient over the surface. The method proposed in this article is applicable for an arbitrary distribution of SCD, and designed to deal with heterogeneous contamination patterns. The developed method is based on the numerical solution of the Fredholm equation of the first kind. The measurement data always contain an error, therefore, the task of the SCD calculation is an ill-posed problem, and the Tikhonov regularisation method (ridge regression) was used to solve it. The article presents the method developed and examples of use. Validation of the method was performed using 38 measurements of the radioactive contamination from 137Cs in soil. It is shown that the method proposed in the article demonstrates a significant superiority in comparison with the MCC method, because it allows more accurate localisation of areas contaminated with radionuclides and is applicable for an arbitrary distribution of SCD.

Published
2019
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23. [Assessment of Erythropoiesis Status in Roach (Rutilus rutilus) of the Radioactively Contaminated Techa River]

Author

Ga, Tryapitsina, Di, Osipov, Ea, Yegoreichenkov, Ea, Shishkina, Rudolfsen G, Hc, Teien, Sneve M, Evgeny Pryakhin, and Av, Akleyev

Subjects
Radioisotopes, Geologic Sediments, Water Pollutants, Radioactive, Erythrocytes, Cyprinidae, Animals, Erythropoiesis, Seasons, Beta Particles
Abstract

At present volumetric activity of β-emitting radionuclides in water at various locations of the Techa River ranges from 5 to 40-Bq/L; a specific activity of β-emitting radionuclides in the bottom sediments at various locations ranges 10 Ito 106 Bq/kg dry weight. A significant increase of the erythroblast content in blood as compared to that in the roach from the reference watercourse (the Miass River) was observed during spawning in the spring. Due to this fact the number of erythrocytes was equal to that in the control animals under chronic radiation exposure at the dose rates of 0.9 and 16 μGy/day, and was insufficient at the dose rate of 108 gGy/day. During summer feeding no changes in the indexes of erythropoiesis in roach were observed under chronic radiation exposure at the dose rate of 0.9 μGy/day; the number of erythrocytes in the peripheral blood declines when the dose rates are 16 and 108 μGy/day. When performing a regression analysis, we revealed a dose-rate-dependent decrease in the absolute number of erythrocytes, normocytes, polychromatocytes, dividing and non-dividing erythroid cells in the peripheral blood of roach from the Techa River and an increase of a relative number of normochromatophylic erythrocytes.

Published
2019

24. Topographical classification of dose distributions: implications for control for worker exposure.

Author

Bragin, Yu, Chizhov, K, Sneve, M K, Tsovyanov, A, Shandala, N, Siegien, K, Smith, G M, I, Tesnov, Krasnoschekov, A, Ksenofontov, A, Kryanev, A, V, Drozdovitch, and Kryuchkov, V

Subjects
LOGNORMAL distribution, CONTINGENT employment, EMPLOYEES, LOGARITHMS, CLASSIFICATION
Abstract

This paper deals with classification of dose distributions of nuclear workers based on antikurtosis (Q) and entropy coefficients (K) and their relationship presented in QK-diagrams. It is shown that determination of the most appropriate distribution to adopt, for a specific data set of a wide range of input data, requires building and analysing QK-diagrams for distributions of logarithms of individual doses. Actual dose distributions for emergency and occupational exposure situations were then considered, as well as doses for one day of work during clean-up and routine activities. It is shown that, in all cases, three types of distributions of logarithms of individual doses were present: normal, Weibull and Chapeau. The location of the representation point of a dose distribution reflects the degree of dose control of the group of workers whose individual doses are collectively displayed in the QK-diagram. The more the representation point of the analysed distribution of the logarithms of the individual dose of a given contingent of workers deviates from the point of the lognormal distribution, the more there was intervention in the process of individual dose accumulation. Thus, QK-diagrams could be used to develop a dose control function. It is shown that the hybrid lognormal distribution, which is widely used in the field of radiation safety, for the purpose of approximation of real dose distributions, is unable to satisfactorily describe many dose distributions arising in aftermath operations and occupational exposure. [ABSTRACT FROM AUTHOR]

Published
2020
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25. The State of Art in Radiation Safety Regulation at the Nuclear Legacy Site on the Kola Peninsula of the Russian Federation: The Point of View of Russian and Foreign Experts

Author

Шандала, Н., primary, Shandala, N., primary, Семенова, М., primary, Semenova, M., primary, Серегин, В., primary, Seregin, V., primary, Григорьев, А., primary, Grigoryev, A., primary, Сневе, М., primary, Sneve, M., primary, Лазо, Э., primary, and Lazo, E, primary

Published
2018
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28. Regulation of the spent nuclear fuel management at the andreeva bay site for temporary storage on the kola peninsula

Author

Уйба, В., primary, Uyba, V., primary, Сневе, М., primary, Sneve, M., primary, Самойлов, А., primary, Samoylov, A., primary, Шандала, Н., primary, Shandala, N., primary, Симаков, А., primary, Simakov, A., primary, Киселев, С., primary, Kiselev, S., primary, Сегень-Иванюк, К., primary, Segen'-Ivanyuk, K., primary, Семенова, М., primary, Semenova, M., primary, Бельских, Ю., primary, Bel'skih, Yu., primary, Крючков, В., primary, Kryuchkov, V., primary, Чижов, К., primary, Chizhov, K., primary, Смит, Г., primary, and Smit, G., primary

Published
2017
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50. Cross-sectional and longitudinal relation between serum 25-hydroxyvitamin D and body mass index: the Tromsø study.

Author

Jorde R, Sneve M, Emaus N, Figenschau Y, and Grimnes G

Abstract

PURPOSE: The serum 25-hydroxyvitamin D (25(OH)D) levels are lower in obese than lean subjects. The present study examines the cross-sectional and longitudinal relations between body mass index (BMI) and serum 25(OH)D, and the serum 25(OH)D response to vitamin D supplementation in relation to BMI. METHODS: The Tromsø study is a longitudinal population-based multipurpose study. The fourth survey was conducted in 1994 and the sixth in 2008. The intervention study was a 1-year placebo-controlled randomized intervention trial, where the results from the 93 subjects given 40,000 IU per week are presented. RESULTS: A total of 10,229 subjects were included in the 2008 cross-sectional study. There was a significant negative association between serum 25(OH)D levels and BMI which was also present during the winter months. Serum 25(OH)D levels varied through seasons, but not BMI. In the longitudinal study from 1994 to 2008 which included 2,656 subjects, change in BMI was a significant negative predictor of change in 25(OH)D. In the intervention study, there was a significant and negative correlation between BMI and serum 25(OH)D both at baseline and at the end of the study. The increase in serum 25(OH)D after 1 year was significantly and inversely related to baseline BMI. CONCLUSIONS: We have confirmed the strong association between serum 25(OH)D and BMI. The very obese need higher vitamin D doses than lean subjects to achieve the same serum 25(OH)D levels. [ABSTRACT FROM AUTHOR]

Published
2010
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