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1.
  • Demetris, A J, et al. (författare)
  • 2016 Comprehensive Update of the Banff Working Group on Liver Allograft Pathology: Introduction of Antibody-Mediated Rejection.
  • 2016
  • Ingår i: American journal of transplantation : official journal of the American Society of Transplantation and the American Society of Transplant Surgeons. - : Elsevier BV. - 1600-6143. ; 16:10, s. 2816-2835
  • Tidskriftsartikel (refereegranskat)abstract
    • The Banff Working Group on Liver Allograft Pathology reviewed and discussed literature evidence regarding antibody-mediated liver allograft rejection at the 11th (Paris, France, June 5-10, 2011), 12th (Comandatuba, Brazil, August 19-23, 2013), and 13th (Vancouver, British Columbia, Canada, October 5-10, 2015) meetings of the Banff Conference on Allograft Pathology. Discussion continued online. The primary goal was to introduce guidelines and consensus criteria for the diagnosis of liver allograft antibody-mediated rejection and provide a comprehensive update of all Banff Schema recommendations. Included are new recommendations for complement component 4d tissue staining and interpretation, staging liver allograft fibrosis, and findings related to immunosuppression minimization. In an effort to create a single reference document, previous unchanged criteria are also included.
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2.
  • Macfarlane, M. D., et al. (författare)
  • Shape abnormalities of the caudate nucleus correlate with poorer gait and balance: Results from a subset of the ladis study
  • 2015
  • Ingår i: The American journal of geriatric psychiatry. - : Elsevier BV. - 1064-7481. ; 23:1, s. 59-
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective Functional deficits seen in several neurodegenerative disorders have been linked with dysfunction in frontostriatal circuits and with associated shape alterations in striatal structures. The severity of visible white matter hyperintensities (WMHs) on magnetic resonance imaging has been found to correlate with poorer performance on measures of gait and balance. This study aimed to determine whether striatal volume and shape changes were correlated with gait dysfunction. Methods Magnetic resonance imaging scans and clinical gait/balance data (scores from the Short Physical Performance Battery [SPPB]) were sourced from 66 subjects in the previously published LADIS trial, performed in nondisabled individuals older than age 65 years with WMHs at study entry. Data were obtained at study entry and at 3-year follow-up. Caudate nuclei and putamina were manually traced using a previously published method and volumes calculated. The relationships between volume and physical performance on the SPPB were investigated with shape analysis using the spherical harmonic shape description toolkit. Results There was no correlation between the severity of WMHs and striatal volumes. Caudate nuclei volume correlated with performance on the SPPB at baseline but not at follow-up, with subsequent shape analysis showing left caudate changes occurred in areas corresponding to inputs of the dorsolateral prefrontal, premotor, and motor cortex. There was no correlation between putamen volumes and performance on the SPPB. Conclusion Disruption in frontostriatal circuits may play a role in mediating poorer physical performance in individuals with WMHs. Striatal volume and shape changes may be suitable biomarkers for functional changes in this population. © 2015 American Association for Geriatric Psychiatry.
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3.
  • Kim, S. W., et al. (författare)
  • Evaluations of NOx and highly reactive VOC emission inventories in Texas and their implications for ozone plume simulations during the Texas Air Quality Study 2006
  • 2011
  • Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 11:22, s. 11361-11386
  • Tidskriftsartikel (refereegranskat)abstract
    • Satellite and aircraft observations made during the 2006 Texas Air Quality Study (TexAQS) detected strong urban, industrial and power plant plumes in Texas. We simulated these plumes using the Weather Research and Forecasting-Chemistry (WRF-Chem) model with input from the US EPA's 2005 National Emission Inventory (NEI-2005), in order to evaluate emissions of nitrogen oxides (NOx = NO + NO2) and volatile organic compounds (VOCs) in the cities of Houston and Dallas-FortWorth. We compared the model results with satellite retrievals of tropospheric nitrogen dioxide (NO2) columns and airborne in-situ observations of several trace gases including NOx and a number of VOCs. The model and satellite NO2 columns agree well for regions with large power plants and for urban areas that are dominated by mobile sources, such as Dallas. How-ever, in Houston, where significant mobile, industrial, and inport marine vessel sources contribute to NOx emissions, the model NO2 columns are approximately 50 %-70 % higher than the satellite columns. Similar conclusions are drawn from comparisons of the model results with the TexAQS 2006 aircraft observations in Dallas and Houston. For Dallas plumes, the model-simulated NO2 showed good agreement with the aircraft observations. In contrast, the model-simulated NO2 is similar to 60 % higher than the aircraft observations in the Houston plumes. Further analysis indicates that the NEI-2005 NOx emissions over the Houston Ship Channel area are overestimated while the urban Houston NOx emissions are reasonably represented. The comparisons of model and aircraft observations confirm that highly reactive VOC emissions originating from industrial sources in Houston are underestimated in NEI-2005. The update of VOC emissions based on Solar Occultation Flux measurements during the field campaign leads to improved model simulations of ethylene, propylene, and formaldehyde. Reducing NOx emissions in the Houston Ship Channel and increasing highly reactive VOC emissions from the point sources in Houston improve the model's capability of simulating ozone (O-3) plumes observed by the NOAA WP-3D aircraft, although the deficiencies in the model O-3 simulations indicate that many challenges remain for a full understanding of the O-3 formation mechanisms in Houston.
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4.
  • Schmidt, R., et al. (författare)
  • White Matter Lesion Progression in LADIS Frequency, Clinical Effects, and Sample Size Calculations
  • 2012
  • Ingår i: Stroke. - : Ovid Technologies (Wolters Kluwer Health). - 0039-2499 .- 1524-4628. ; 43:10, s. 2643-2647
  • Tidskriftsartikel (refereegranskat)abstract
    • Background and Purpose-White matter lesion (WML) progression has been advocated as a surrogate marker in intervention trials on cerebral small vessel disease. We assessed the rate of visually rated WML progression, studied correlations between lesion progression and cognition, and estimated sample sizes for clinical trials with pure WML progression vs combined WML progression-cognitive outcomes. Methods-Those 394 participants of the Leukoaraiosis and Disability Study (LADIS) study with magnetic resonance imaging scanning at baseline and 3-year follow-up were analyzed. WML progression rating relied on the modified Rotterdam Progression Scale. The Vascular Dementia Assessment Scale global score and a composite score of specific executive function tests assessed longitudinal change in cognition. Sample size calculations were based on the assumption that treatment reduces WML progression by 1 grade on the Rotterdam Progression Scale. Results-WML progression related to deterioration in cognitive functioning. This relationship was less pronounced in subjects with early confluent and confluent lesions. Consequently, studies in which the outcome is cognitive change resulting from treatment effects on lesion progression will need between 1809 subjects per treatment arm when using executive tests and up to 18 853 subjects when using the Vascular Dementia Assessment Scale score. Studies having WML progression as the sole outcome will need only 58 or 70 individuals per treatment arm. Conclusions-WML progression is an interesting outcome for proof-of-concept studies in cerebral small vessel disease. If cognitive outcome measures are added to protocols, then sample size estimates increase substantially. Our data support the use of an executive test battery rather than the Vascular Dementia Assessment Scale as the primary cognitive outcome measure. (Stroke. 2012; 43:2643-2647.)
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5.
  • Benisty, S, et al. (författare)
  • Location of lacunar infarcts correlates with cognition in a sample of non-disabled subjects with age-related white-matter changes: the LADIS study.
  • 2009
  • Ingår i: Journal of neurology, neurosurgery, and psychiatry. - : BMJ. - 1468-330X .- 0022-3050. ; 80:5, s. 478-83
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES: In cerebral small vessel disease, white-matter hyperintensities (WMH) and lacunes are both related to cognition. Still, their respective contribution in older people remains unclear. The purpose of this study is to assess the topographic distribution of lacunes and determine whether it has an impact on cognitive functions in a sample of non-disabled patients with age-related white-matter changes. METHODS: Data were drawn from the baseline evaluation of the LADIS (Leucoaraioisis and Disability study) cohort of non-disabled subjects beyond 65 years of age. The neuropsychological evaluation was based on the Mini Mental Status Examination (MMSE), a modified Alzheimer Diseases Assessment Scale for global cognitive functions, and compound Z scores for memory, executive functions, speed and motor control. WMH were rated according to the Fazekas scale; the number of lacunes was assessed in the following areas: lobar white matter, putamen/pallidum, thalamus, caudate nucleus, internal/external capsule, infratentorial areas. An analysis of covariance was performed after adjustment for possible confounders. RESULTS: Among 633 subjects, 47% had at least one lacune (31% at least one within basal ganglia). The presence of lacunes in the thalamus was associated with lower scores of MMSE (beta = -0.61; p = 0.043), and worse compound scores for speed and motor control (beta = -0.25; p = 0.006), executive functions (beta = -0.19; p = 0.022) independently of the cognitive impact of WMH. There was also a significant negative association between the presence of lacunes in putamen/pallidum and the memory compound Z score (beta = -0.13; p = 0.038). By contrast, no significant negative association was found between cognitive parameters and the presence of lacunes in internal capsule, lobar white matter and caudate nucleus. CONCLUSION: In non-disabled elderly subjects with leucoaraisosis, the location of lacunes within subcortical grey matter is a determinant of cognitive impairment, independently of the extent of WMH.
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6.
  • Clausen, Niels, et al. (författare)
  • Similar bleeding phenotype in young children with haemophilia A or B : A cohort study
  • 2014
  • Ingår i: Haemophilia. - : Wiley. - 1351-8216. ; 20:6, s. 747-755
  • Tidskriftsartikel (refereegranskat)abstract
    • The bleeding phenotype has been suggested to differ between haemophilia A and B. More knowledge on the bleeding phenotype at initiation of treatment is important to optimize patient care. The aim of this study was to investigate the severity of the bleeding phenotype and the variation in bleeding in children with severe or moderate haemophilia A and B. Consecutive, previously untreated patients with severe or moderate haemophilia A and B (factor VIII or IX activity <0.01 or 0.01-0.05 IU mL-1 respectively) born between January 1st 2000 and January 1st 2010 were included. Primary outcome was severity of bleeding tendency. Secondary outcome was variation in bleeding pattern. A total of 582 patients with severe haemophilia A and 76 with severe haemophilia B did not differ in age at first exposure to clotting factor (0.81 vs. 0.88 years, P = 0.20), age at first bleed (0.82 vs. 0.88 years, P = 0.36), and age at first joint bleed (1.18 vs. 1.20 years, P = 0.59). Patients with moderate haemophilia were older compared to patients with severe haemophilia. In patients with moderate haemophilia there were no clear differences between haemophilia A and B. Severity and variation in bleeding phenotype are similar during the early stage of treatment in patients with severe and moderate haemophilia A and B respectively. The findings imply that children with haemophilia B should be observed and treated as vigilantly as those with haemophilia A.
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7.
  • Firbank, M. J., et al. (författare)
  • Relationship between progression of brain white matter changes and late-life depression: 3-year results from the LADIS study
  • 2012
  • Ingår i: British Journal of Psychiatry. - : Royal College of Psychiatrists. - 0007-1250 .- 1472-1465. ; 201:1, s. 40-45
  • Tidskriftsartikel (refereegranskat)abstract
    • Background Brain white matter changes (WMC) and depressive symptoms are linked, but the directionality of this association remains unclear. Aims To investigate the relationship between baseline and incident depression and progression of white matter changes. Method In a longitudinal multicentre pan-European study (Leukoaraiosis and Disability in the elderly, LADIS), participants aged over 64 underwent baseline magnetic resonance imaging (MRI) and clinical assessments. Repeat scans were obtained at 3 years. Depressive outcomes were assessed in terms of depressive episodes and the Geriatric Depression Scale (GDS). Progression of WMC was measured using the modified Rotterdam Progression scale. Results Progression of WMC was significantly associated with incident depression during year 3 of the study (P = 0.002) and remained significant after controlling for transition to disability, baseline WMC and baseline history of depression. There was no significant association between progression of WMC and GDS score, and no significant relationship between progression of WMC and history of depression at baseline. Conclusions Our results support the vascular depression hypothesis and implicate WMC as causal in the pathogenesis of late-life depression.
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8.
  • Jokinen, H., et al. (författare)
  • Diffusion changes predict cognitive and functional outcome: The LADIS study
  • 2013
  • Ingår i: Annals of Neurology. - : Wiley. - 0364-5134. ; 73:5, s. 576-583
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective A study was undertaken to determine whether diffusion-weighted imaging (DWI) abnormalities in normal-appearing brain tissue (NABT) and in white matter hyperintensities (WMH) predict longitudinal cognitive decline and disability in older individuals independently of the concomitant magnetic resonance imaging (MRI) findings. Methods A total of 340 LADIS (Leukoaraiosis and Disability Study) participants, aged 65 to 84 years, underwent brain MRI including DWI at baseline. Neuropsychological and functional assessments were carried out at study entry and repeated annually over a 3-year observational period. Linear mixed models and Cox regression survival analysis adjusted for demographics, WMH volume, lacunes, and brain atrophy were used to evaluate the independent effect of the DWI measures on change in cognitive performance and functional abilities. Results The mean global apparent diffusion coefficient (ADC) and the relative peak height and peak position of the ADC histogram in NABT predicted faster rate of decline in a composite score for speed and motor control. Higher mean ADC and lower peak height were also related to deterioration in executive functions and memory (specifically working memory), with peak height also being related to more rapid transition to disability and higher rate of mortality. Mean ADC in WMH had less pronounced effects on cognitive and functional outcomes. Interpretation DWI microstructural changes in NABT predict faster decline in psychomotor speed, executive functions, and working memory regardless of conventional MRI findings. Moreover, these changes are related to functional disability and higher mortality. Ann Neurol 2013;73:576–583
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9.
  • Parrish, D. D., et al. (författare)
  • Primary and secondary sources of formaldehyde in urban atmospheres: Houston Texas region
  • 2012
  • Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 12:7, s. 3273-3288
  • Tidskriftsartikel (refereegranskat)abstract
    • We evaluate the rates of secondary production and primary emission of formaldehyde (CH2O) from petrochemical industrial facilities and on-road vehicles in the Houston Texas region. This evaluation is based upon ambient measurements collected during field studies in 2000, 2006 and 2009. The predominant CH2O source (92 +/- 4% of total) is secondary production formed during the atmospheric oxidation of highly reactive volatile organic compounds (HRVOCs) emitted from the petrochemical facilities. Smaller contributions are primary emissions from these facilities (4 +/- 2%), and secondary production (similar to 3%) and primary emissions (similar to 1%) from vehicles. The primary emissions from both sectors are well quantified by current emission inventories. Since secondary production dominates, control efforts directed at primary CH2O emissions cannot address the large majority of CH2O sources in the Houston area, although there may still be a role for such efforts. Ongoing efforts to control alkene emissions from the petrochemical facilities, as well as volatile organic compound emissions from the motor vehicle fleet, will effectively reduce the CH2O concentrations in the Houston region. We do not address other emission sectors, such as off-road mobile sources or secondary formation from biogenic hydrocarbons. Previous analyses based on correlations between ambient concentrations of CH2O and various marker species have suggested much larger primary emissions of CH2O, but those results neglect confounding effects of dilution and loss processes, and do not demonstrate the causes of the observed correlations. Similar problems must be suspected in any source apportionment analysis of secondary species based upon correlations of ambient concentrations of pollutants.
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11.
  • De Gouw, J. A., et al. (författare)
  • Airborne Measurements of Ethene from Industrial Sources Using Laser Photo-Acoustic Spectroscopy
  • 2009
  • Ingår i: Environmental Science & Technology. - : American Chemical Society (ACS). - 0013-936X .- 1520-5851. ; 43:7, s. 2437-2442
  • Tidskriftsartikel (refereegranskat)abstract
    • A laser photoacoustic spectroscopy (LPAS) instrument was developed and used for aircraft measurements of ethene from industrial sources near Houston, Texas. The instrument provided 20 s measurements with a detection limit of less than 0.7 ppbv. Data from this instrument and from the GC-FID analysis of air samples collected in flight agreed within 15% on average. Ethene fluxes from the Mt. Belvieu chemical complex to the northeast of Houston were quantified during 10 different flights. The average flux was 520 +/- 140 kg h(-1) in agreement with independent results from solar occultation flux (SOF) measurements, and roughly an order of magnitude higher than regulatory emission inventories indicate. This study shows that ethene emissions are routinely at levels that qualify as emission upsets, which need to be reported to regional air quality managers.
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12.
  • Eikelboom, Willem S., et al. (författare)
  • The reporting of neuropsychiatric symptoms in electronic health records of individuals with Alzheimer’s disease : a natural language processing study
  • 2023
  • Ingår i: Alzheimer's Research and Therapy. - 1758-9193. ; 15:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Neuropsychiatric symptoms (NPS) are prevalent in the early clinical stages of Alzheimer’s disease (AD) according to proxy-based instruments. Little is known about which NPS clinicians report and whether their judgment aligns with proxy-based instruments. We used natural language processing (NLP) to classify NPS in electronic health records (EHRs) to estimate the reporting of NPS in symptomatic AD at the memory clinic according to clinicians. Next, we compared NPS as reported in EHRs and NPS reported by caregivers on the Neuropsychiatric Inventory (NPI). Methods: Two academic memory clinic cohorts were used: the Amsterdam UMC (n = 3001) and the Erasmus MC (n = 646). Patients included in these cohorts had MCI, AD dementia, or mixed AD/VaD dementia. Ten trained clinicians annotated 13 types of NPS in a randomly selected training set of n = 500 EHRs from the Amsterdam UMC cohort and in a test set of n = 250 EHRs from the Erasmus MC cohort. For each NPS, a generalized linear classifier was trained and internally and externally validated. Prevalence estimates of NPS were adjusted for the imperfect sensitivity and specificity of each classifier. Intra-individual comparison of the NPS classified in EHRs and NPS reported on the NPI were conducted in a subsample (59%). Results: Internal validation performance of the classifiers was excellent (AUC range: 0.81–0.91), but external validation performance decreased (AUC range: 0.51–0.93). NPS were prevalent in EHRs from the Amsterdam UMC, especially apathy (adjusted prevalence = 69.4%), anxiety (adjusted prevalence = 53.7%), aberrant motor behavior (adjusted prevalence = 47.5%), irritability (adjusted prevalence = 42.6%), and depression (adjusted prevalence = 38.5%). The ranking of NPS was similar for EHRs from the Erasmus MC, although not all classifiers obtained valid prevalence estimates due to low specificity. In both cohorts, there was minimal agreement between NPS classified in the EHRs and NPS reported on the NPI (all kappa coefficients < 0.28), with substantially more reports of NPS in EHRs than on NPI assessments. Conclusions: NLP classifiers performed well in detecting a wide range of NPS in EHRs of patients with symptomatic AD visiting the memory clinic and showed that clinicians frequently reported NPS in these EHRs. Clinicians generally reported more NPS in EHRs than caregivers reported on the NPI.
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13.
  • Jokinen, H., et al. (författare)
  • Brain atrophy accelerates cognitive decline in cerebral small vessel disease The LADIS study
  • 2012
  • Ingår i: Neurology. - 0028-3878. ; 78:22, s. 1785-1792
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To examine the independent contributions and combined interactions of medial temporal lobe atrophy (MTA), cortical and subcortical atrophy, and white matter lesion (WML) volume in longitudinal cognitive performance. Methods: A total of 477 subjects with age-related WML were evaluated with brain MRI and annual neuropsychological examinations in 3-year follow-up. Baseline MRI determinants of cognitive decline were analyzed with linear mixed models controlling for multiple confounders. Results: MTA and subcortical atrophy predicted significantly steeper rate of decline in global cognitive measures as well as compound scores for psychomotor speed, executive functions, and memory after adjusting for age, gender, education, lacunes/infarcts, and WML volume. Cortical atrophy independently predicted decline in psychomotor speed. WML volume remained significantly associated with cognitive decline even after controlling for the atrophy scores. Moreover, significant synergistic interactions were found between WML and atrophy measures in overall cognitive performance across time and the rate of cognitive decline. Synergistic effects were also observed between baseline lacunar infarcts and all atrophy measures on change in psychomotor speed. The main results remained robust after exclusion of subjects with clinical stroke or incident dementia, and after additional adjustments for progression of WML and lacunes. Conclusions: Brain atrophy and WML are independently related to longitudinal cognitive decline in small vessel disease. MTA, subcortical, and cortical atrophy seem to potentiate the effect of WML and lacunes on cognitive decline. Neurology (R) 2012;78:1785-1792
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14.
  • Jokinen, H, et al. (författare)
  • Incident lacunes influence cognitive decline: the LADIS study.
  • 2011
  • Ingår i: Neurology. - 0028-3878 .- 1526-632X. ; 76:22, s. 1872-8
  • Tidskriftsartikel (refereegranskat)abstract
    • In cerebral small vessel disease, the core MRI findings include white matter lesions (WML) and lacunar infarcts. While the clinical significance of WML is better understood, the contribution of lacunes to the rate of cognitive decline has not been established. This study investigated whether incident lacunes on MRI determine longitudinal cognitive change in elderly subjects with WML.
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16.
  • Teodorczuk, A., et al. (författare)
  • White matter changes and late-life depressive symptoms - Longitudinal study
  • 2007
  • Ingår i: BRITISH JOURNAL OF PSYCHIATRY. - : Royal College of Psychiatrists. - 0007-1250 .- 1472-1465. ; 191, s. 212-217
  • Tidskriftsartikel (refereegranskat)abstract
    • Evidence from cross-sectional studies suggests a link between cerebral age-related white matter changes and depressive symptoms in older people, although the temporal association remains unclear.AimsTo investigate age-related white matter changes on magnetic resonance imaging (MRI) as an independent predictor of depressive symptoms at 1 year after controlling for known confounders.MethodIn a pan-European multicentre study of 639 older adults without significant disability, MRI white matter changes and demographic and clinical variables, including cognitive scores, quality of life, disability and depressive symptoms, were assessed at baseline. Clinical assessments were repeated at 1 year.ResultsUsing logistic regression analysis, severity of white matter changes was shown to independently and significantly predict depressive symptoms at 1 year after controlling for baseline depressive symptoms, quality of life and worsening disability (P<0.01).ConclusionsWhite matter changes pre-date and are associated with the development of depressive symptoms. This has implications for treatment and prevention of depression in later life.
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17.
  • Zhang, Haofei, et al. (författare)
  • Monoterpenes are the largest source of summertime organic aerosol in the southeastern United States
  • 2018
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 0027-8424 .- 1091-6490. ; 115:9, s. 2038-2043
  • Tidskriftsartikel (refereegranskat)abstract
    • The chemical complexity of atmospheric organic aerosol (OA) has caused substantial uncertainties in understanding its origins and environmental impacts. Here, we provide constraints on OA origins through compositional characterization with molecular-level details. Our results suggest that secondary OA (SOA) from monoterpene oxidation accounts for approximately half of summertime fine OA in Centreville, AL, a forested area in the southeastern United States influenced by anthropogenic pollution. We find that different chemical processes involving nitrogen oxides, during days and nights, play a central role in determining the mass of monoterpene SOA produced. These findings elucidate the strong anthropogenic–biogenic interaction affecting ambient aerosol in the southeastern United States and point out the importance of reducing anthropogenic emissions, especially under a changing climate, where biogenic emissions will likely keep increasing.
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20.
  • Jonsson, Michael, 1955, et al. (författare)
  • Low Cerebrospinal Fluid Sulfatide Predicts Progression of White Matter Lesions - The LADIS Study
  • 2012
  • Ingår i: Dementia and Geriatric Cognitive Disorders. - : S. Karger AG. - 1420-8008 .- 1421-9824. ; 34:1, s. 61-67
  • Tidskriftsartikel (refereegranskat)abstract
    • Background/Aims: Demyelination and axonal degeneration are the hallmarks of established white matter lesions (WML). The neurochemistry of ongoing WML is only partially known. We explored cerebrospinal fluid (CSF) substances as markers of brain tissue damage in relation to progression of WML rated on magnetic resonance imaging. Methods: CSF from elderly individuals with WML was analyzed for amyloid markers, total tau, hyperphosphorylated t, neurofilament protein light subunit, sulfatide and CSF/serum-albumin ratio. After 3 years, a follow-up magnetic resonance imaging was performed. Progression of WML was rated using the Rotterdam Progression Scale (RPS). Results: 37 subjects (age 73.6 +/- 4.6 years) were included. Subjects with more pronounced progression (RPS > 2; n = 15) had lower mean sulfatide concentration at baseline as compared to subjects with no or minimal progression (RPS 0-2; n = 22) according to univariate analyses (p = 0.009). Sulfatide was the only biomarker that predicted the RPS score according to regression analysis, explaining 18.9% of the total variance (r = 0.38, p = 0.015). Conclusion: The correlation of CSF sulfatide levels and RPS scores may reflect a remyelination response to the demyelination process associated with WML. Furthermore, the results strengthen the notion that WML pathology is different from that of Alzheimer's disease.
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21.
  • Lee, Ben H, et al. (författare)
  • Highly functionalized organic nitrates in the southeast United States: Contribution to secondary organic aerosol and reactive nitrogen budgets.
  • 2016
  • Ingår i: Proceedings of the National Academy of Sciences of the United States of America. - : Proceedings of the National Academy of Sciences. - 1091-6490. ; 113:6, s. 1516-21
  • Tidskriftsartikel (refereegranskat)abstract
    • Speciated particle-phase organic nitrates (pONs) were quantified using online chemical ionization MS during June and July of 2013 in rural Alabama as part of the Southern Oxidant and Aerosol Study. A large fraction of pONs is highly functionalized, possessing between six and eight oxygen atoms within each carbon number group, and is not the common first generation alkyl nitrates previously reported. Using calibrations for isoprene hydroxynitrates and the measured molecular compositions, we estimate that pONs account for 3% and 8% of total submicrometer organic aerosol mass, on average, during the day and night, respectively. Each of the isoprene- and monoterpenes-derived groups exhibited a strong diel trend consistent with the emission patterns of likely biogenic hydrocarbon precursors. An observationally constrained diel box model can replicate the observed pON assuming that pONs (i) are produced in the gas phase and rapidly establish gas-particle equilibrium and (ii) have a short particle-phase lifetime (∼2-4 h). Such dynamic behavior has significant implications for the production and phase partitioning of pONs, organic aerosol mass, and reactive nitrogen speciation in a forested environment.
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22.
  • Poggesi, A., et al. (författare)
  • Cerebral white matter changes are associated with abnormalities on neurological examination in non-disabled elderly: the LADIS study
  • 2013
  • Ingår i: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 260:4, s. 1014-1021
  • Tidskriftsartikel (refereegranskat)abstract
    • Cerebral white matter changes (WMC) are associated with motor, cognitive, mood, urinary disturbances, and disability, but little is known about the prevalence of neurological signs in patients with these brain lesions. We assessed the presence and occurrence of neurological abnormalities over a 3-year period and their possible associations with WMC in a cohort of initially non-disabled elderly subjects. Data from the multicenter Leukoaraiosis And DISability study were used. A standard neurological examination was performed at baseline and at each of the annual follow-up visits. A standard MRI scan was performed at baseline and after 3-years. WMC severity was graded as mild, moderate, or severe on the Fazekas scale, while the Rotterdam scale was used to assess progression. Infarcts and their occurrence were also assessed. Six hundred and thirty-nine non-disabled subjects were enrolled (mean age 74.1 +/- A 5.0, M/F: 288/351). Severe WMC at baseline were associated with gait and stance abnormalities, upper motor signs, and fingertap slowing. This effect was independent of age, sex, lacunar and non-lacunar infarcts. The occurrence of stance abnormalities, upper motor signs, primitive reflexes and fingertap slowing during the 3-year follow-up period was associated with both baseline WMC load and their progression. The occurrence of the same abnormalities plus extrapyramidal and primitive reflexes was associated with incident lacunar infarcts. In our cohort of non-disabled elders, severe WMC were associated with the presence and the occurrence of neurological signs, independently of other vascular brain lesions, confirming that these lesions have clinical relevance.
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23.
  • Poggesi, A., et al. (författare)
  • Neurological abnormalities predict disability: the LADIS (Leukoaraiosis And DISability) study
  • 2014
  • Ingår i: Journal of Neurology. - : Springer Science and Business Media LLC. - 0340-5354 .- 1432-1459. ; 261:6, s. 1160-1169
  • Tidskriftsartikel (refereegranskat)abstract
    • To investigate the role of neurological abnormalities and magnetic resonance imaging (MRI) lesions in predicting global functional decline in a cohort of initially independent-living elderly subjects. The Leukoaraiosis And DISability (LADIS) Study, involving 11 European centres, was primarily aimed at evaluating age-related white matter changes (ARWMC) as an independent predictor of the transition to disability (according to Instrumental Activities of Daily Living scale) or death in independent elderly subjects that were followed up for 3 years. At baseline, a standardized neurological examination was performed. MRI assessment included age-related white matter changes (ARWMC) grading (mild, moderate, severe according to the Fazekas' scale), count of lacunar and non-lacunar infarcts, and global atrophy rating. Of the 633 (out of the 639 enrolled) patients with follow-up information (mean age 74.1 +/- A 5.0 years, 45 % males), 327 (51.7 %) presented at the initial visit with a parts per thousand yen1 neurological abnormality and 242 (38 %) reached the main study outcome. Cox regression analyses, adjusting for MRI features and other determinants of functional decline, showed that the baseline presence of any neurological abnormality independently predicted transition to disability or death [HR (95 % CI) 1.53 (1.01-2.34)]. The hazard increased with increasing number of abnormalities. Among MRI lesions, only ARWMC of severe grade independently predicted disability or death [HR (95 % CI) 2.18 (1.37-3.48)]. In our cohort, presence and number of neurological examination abnormalities predicted global functional decline independent of MRI lesions typical of the aging brain and other determinants of disability in the elderly. Systematically checking for neurological examination abnormalities in older patients may be cost-effective in identifying those at risk of functional decline.
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24.
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25.
  • Coomans, Emma M., et al. (författare)
  • In vivo tau pathology is associated with synaptic loss and altered synaptic function
  • 2021
  • Ingår i: Alzheimer's Research and Therapy. - : Springer Science and Business Media LLC. - 1758-9193. ; 13:1
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The mechanism of synaptic loss in Alzheimer’s disease is poorly understood and may be associated with tau pathology. In this combined positron emission tomography (PET) and magnetoencephalography (MEG) study, we aimed to investigate spatial associations between regional tau pathology ([18F]flortaucipir PET), synaptic density (synaptic vesicle 2A [11C]UCB-J PET) and synaptic function (MEG) in Alzheimer’s disease. Methods: Seven amyloid-positive Alzheimer’s disease subjects from the Amsterdam Dementia Cohort underwent dynamic 130-min [18F]flortaucipir PET, dynamic 60-min [11C]UCB-J PET with arterial sampling and 2 × 5-min resting-state MEG measurement. [18F]flortaucipir- and [11C]UCB-J-specific binding (binding potential, BPND) and MEG spectral measures (relative delta, theta and alpha power; broadband power; and peak frequency) were assessed in cortical brain regions of interest. Associations between regional [18F]flortaucipir BPND, [11C]UCB-J BPND and MEG spectral measures were assessed using Spearman correlations and generalized estimating equation models. Results: Across subjects, higher regional [18F]flortaucipir uptake was associated with lower [11C]UCB-J uptake. Within subjects, the association between [11C]UCB-J and [18F]flortaucipir depended on within-subject neocortical tau load; negative associations were observed when neocortical tau load was high, gradually changing into opposite patterns with decreasing neocortical tau burden. Both higher [18F]flortaucipir and lower [11C]UCB-J uptake were associated with altered synaptic function, indicative of slowing of oscillatory activity, most pronounced in the occipital lobe. Conclusions: These results indicate that in Alzheimer’s disease, tau pathology is closely associated with reduced synaptic density and synaptic dysfunction.
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26.
  • Gouw, Alida A, et al. (författare)
  • On the etiology of incident brain lacunes: longitudinal observations from the LADIS study.
  • 2008
  • Ingår i: Stroke; a journal of cerebral circulation. - 1524-4628. ; 39:11, s. 3083-5
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND AND PURPOSE: We investigated regional differences in MRI characteristics and risk factor profiles of incident lacunes over a 3-year period. METHODS: Baseline and 3-year follow-up MRI were collected within the LADIS study (n=358). Incident lacunes were characterized with respect to brain region, their appearance within pre-existent white matter hyperintensities (WMH), surrounding WMH size, and risk factors. RESULTS: 106 incident lacunes were observed in 62 patients (58 subcortical white matter [WM], 35 basal ganglia, and 13 infratentorial). Incident subcortical WM lacunes occurred more often within preexisting WMH (P=0.01) and were mostly accompanied by new and expanded WMH (P<0.001), compared to incident basal ganglia and infratentorial lacunes. Risk factors for incident subcortical WM lacunes were history of hypertension and stroke, whereas atrial fibrillation predicted incident basal ganglia/infratentorial lacunes. CONCLUSIONS: Differences in relation to WMH and risk factor profiles may suggest that incident lacunes in the subcortical WM have a different pathogenesis than those in the basal ganglia and infratentorial region.
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27.
  • Gouw, Alida A, et al. (författare)
  • Progression of white matter hyperintensities and incidence of new lacunes over a 3-year period: the Leukoaraiosis and Disability study.
  • 2008
  • Ingår i: Stroke; a journal of cerebral circulation. - 1524-4628. ; 39:5, s. 1414-20
  • Tidskriftsartikel (refereegranskat)abstract
    • BACKGROUND AND PURPOSE: We studied the natural course of white matter hyperintensities (WMH) and lacunes, the main MRI representatives of small vessel disease, over time and evaluated possible predictors for their development. METHODS: Baseline and repeat MRI (3-year follow-up) were collected within the multicenter, multinational Leukoaraiosis and Disability study (n=396). Baseline WMH were scored on MRI by the Fazekas scale and the Scheltens scale. WMH progression was assessed using the modified Rotterdam Progression scale (absence/presence of progression in 9 brain regions). Baseline and new lacunes were counted per region. WMH and lacunes at baseline and vascular risk factors were evaluated as predictors of WMH progression and new lacunes. RESULTS: WMH progressed (mean+/-SD=1.9+/-1.8) mostly in the subcortical white matter, where WMH was also most prevalent at baseline. The majority of new lacunes, which were found in 19% of the subjects (maximum=9), also appeared in the subcortical white matter, mainly of the frontal lobes, whereas most baseline lacunes were located in the basal ganglia. Baseline WMH and lacunes predicted both WMH progression and new lacunes. Furthermore, previous stroke, diabetes, and blood glucose were risk factors for WMH progression. Male sex, hypertension, systolic blood pressure, previous stroke, body mass index, high-density lipoprotein, and triglyceride levels were risk factors for new lacunes. CONCLUSIONS: WMH and lacunes progressed over time, predominantly in the subcortical white matter. Progression was observed especially in subjects with considerable WMH and lacunes at baseline. Moreover, the presence of vascular risk factors at baseline predicted WMH progression and new lacunes over a 3-year period.
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28.
  • Gouw, Samantha C., et al. (författare)
  • Intensity of factor VIII treatment and inhibitor development in children with severe hemophilia A: the RODIN study
  • 2013
  • Ingår i: Blood. - : American Society of Hematology. - 1528-0020 .- 0006-4971. ; 121:20, s. 4046-4055
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective of this study was to examine the association of the intensity of treatment, ranging from high-dose intensive factor VIII (FVIII) treatment to prophylactic treatment, with the inhibitor incidence among previously untreated patients with severe hemophilia A. This cohort study aimed to include consecutive patients with a FVIII activity <0.01 IU/mL, born between 2000 and 2010, and observed during their first 75 FVIII exposure days. Intensive FVIII treatment of hemorrhages or surgery at the start of treatment was associated with an increased inhibitor risk (adjusted hazard ratio [aHR], 2.0; 95% confidence interval [CI], 1.3-3.0). High-dose FVIII treatment was associated with a higher inhibitor risk than low-dose FVIII treatment (aHR, 2.3; 95% CI, 1.0-4.8). Prophylaxis was only associated with a decreased overall inhibitor incidence after 20 exposure days of FVIII. The association with prophylaxis was more pronounced in patients with low-risk F8 genotypes than in patients with high-risk F8 genotypes (aHR, 0.61, 95% CI, 0.19-2.0 and aHR, 0.85, 95% CI, 0.51-1.4, respectively). In conclusion, our findings suggest that in previously untreated patients with severe hemophilia A, high-dosed intensive FVIII treatment increases inhibitor risk and prophylactic FVIII treatment decreases inhibitor risk, especially in patients with low-risk F8 mutations.
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29.
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30.
  • Lee, Shan Hu, et al. (författare)
  • Isoprene suppression of new particle formation : Potential mechanisms and implications
  • 2016
  • Ingår i: Journal of Geophysical Research: Atmospheres. - 2169-897X. ; 121:24, s. 14-635
  • Tidskriftsartikel (refereegranskat)abstract
    • Secondary aerosols formed from anthropogenic pollutants and natural emissions have substantial impacts on human health, air quality, and the Earth's climate. New particle formation (NPF) contributes up to 70% of the global production of cloud condensation nuclei (CCN), but the effects of biogenic volatile organic compounds (BVOCs) and their oxidation products on NPF processes in forests are poorly understood. Observations show that isoprene, the most abundant BVOC, suppresses NPF in forests. But the previously proposed chemical mechanism underlying this suppression process contradicts atmospheric observations. By reviewing observations made in other forests, it is clear that NPF rarely takes place during the summer when emissions of isoprene are high, even though there are sufficient concentrations of monoterpenes. But at present it is not clear how isoprene and its oxidation products may change the oxidation chemistry of terpenes and how NOx and other atmospheric key species affect NPF in forest environments. Future laboratory experiments with chemical speciation of gas phase nucleation precursors and clusters and chemical composition of particles smaller than 10 nm are required to understand the role of isoprene in NPF. Our results show that climate models can overpredict aerosol's first indirect effect when not considering the absence of NPF in the southeastern U.S. forests during the summer using the current nucleation algorithm that includes only sulfuric acid and total concentrations of low-volatility organic compounds. This highlights the importance of understanding NPF processes as function of temperature, relative humidity, and BVOC compositions to make valid predictions of NPF and CCN at a wide range of atmospheric conditions.
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31.
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32.
  • Ropele, Stefan, et al. (författare)
  • Quantitation of brain tissue changes associated with white matter hyperintensities by diffusion-weighted and magnetization transfer imaging: the LADIS (Leukoaraiosis and Disability in the Elderly) study.
  • 2009
  • Ingår i: Journal of magnetic resonance imaging : JMRI. - : Wiley. - 1053-1807 .- 1522-2586. ; 29:2, s. 268-74
  • Tidskriftsartikel (refereegranskat)abstract
    • PURPOSE: To explore the value of diffusion-weighted imaging (DWI) and magnetization transfer imaging (MTI) for the improved detection and quantification of cerebral tissue changes associated with ageing and white matter hyperintensities (WMH). MATERIALS AND METHODS: DWI (n = 340) and MTI (n = 177) were performed in nine centers of the multinational Leukoaraiosis And DISability (LADIS) study investigating the impact of WMH on 65- to 85-year-old individuals without prior disability. We assessed the apparent diffusion coefficient (ADC) and magnetization transfer ratio (MTR) of normal appearing brain tissue (NABT) and within WMH and related them to subjects' age and WHM severity according to the Fazekas score. RESULTS: ADC and MTR values showed a significant inter-site variation, which was stronger for the MTR. After z-transformation multiple regression analysis revealed WMH severity and age as significant predictors of global ADC and MTR changes. Only lesional ADC, but not MTR was related to WMH severity. CONCLUSION: ADC and MTR are both sensitive for age and WMH related changes in NABT. The ADC is more sensitive for tissue changes within WMH and appears to be more robust for multicenter settings.
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33.
  • Schoonhoven, Deborah N., et al. (författare)
  • Tau protein spreads through functionally connected neurons in Alzheimer's disease : a combined MEG/PET study
  • 2023
  • Ingår i: Brain. - 0006-8950. ; 146:10, s. 4040-4054
  • Tidskriftsartikel (refereegranskat)abstract
    • Recent studies on Alzheimer's disease (AD) suggest that tau proteins spread through the brain following neuronal connections. Several mechanisms could be involved in this process: spreading between brain regions that interact strongly (functional connectivity); through the pattern of anatomical connections (structural connectivity); or simple diffusion. Using magnetoencephalography (MEG), we investigated which spreading pathways influence tau protein spreading by modelling the tau propagation process using an epidemic spreading model. We compared the modelled tau depositions with 18F-flortaucipir PET binding potentials at several stages of the AD continuum. In this cross-sectional study, we analysed source-reconstructed MEG data and dynamic 100-min 18F-flortaucipir PET from 57 subjects positive for amyloid-β pathology [preclinical AD (n = 16), mild cognitive impairment (MCI) due to AD (n = 16) and AD dementia (n = 25)]. Cognitively healthy subjects without amyloid-β pathology were included as controls (n = 25). Tau propagation was modelled as an epidemic process (susceptible-infected model) on MEG-based functional networks [in alpha (8-13 Hz) and beta (13-30 Hz) bands], a structural or diffusion network, starting from the middle and inferior temporal lobe. The group-level network of the control group was used as input for the model to predict tau deposition in three stages of the AD continuum. To assess performance, model output was compared to the group-specific tau deposition patterns as measured with 18F-flortaucipir PET. We repeated the analysis by using networks of the preceding disease stage and/or using regions with most observed tau deposition during the preceding stage as seeds. In the preclinical AD stage, the functional networks predicted most of the modelled tau-PET binding potential, with best correlations between model and tau-PET [corrected amplitude envelope correlation (AEC-c) alpha C = 0.584; AEC-c beta C = 0.569], followed by the structural network (C = 0.451) and simple diffusion (C = 0.451). Prediction accuracy declined for the MCI and AD dementia stages, although the correlation between modelled tau and tau-PET binding remained highest for the functional networks (C = 0.384; C = 0.376). Replacing the control-network with the network from the preceding disease stage and/or alternative seeds improved prediction accuracy in MCI but not in the dementia stage. These results suggest that in addition to structural connections, functional connections play an important role in tau spread, and highlight that neuronal dynamics play a key role in promoting this pathological process. Aberrant neuronal communication patterns should be taken into account when identifying targets for future therapy. Our results also suggest that this process is more important in earlier disease stages (preclinical AD/MCI); possibly, in later stages, other processes may be influential.
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34.
  • Wong, Peter Y. H., et al. (författare)
  • Testing abstract behavioral specifications
  • 2014
  • Ingår i: International Journal on Software Tools for Technology Transfer. - : Springer. - 1433-2779 .- 1433-2787. ; 17:1, s. 107-119
  • Tidskriftsartikel (refereegranskat)abstract
    • We present a range of testing techniques for the Abstract Behavioral Specification (ABS) language and apply them to an industrial case study. ABS is a formal modeling language for highly variable, concurrent, component-based systems. The nature of these systems makes them susceptible to the introduction of subtle bugs that are hard to detect in the presence of steady adaptation. While static analysis techniques are available for an abstract language such as ABS, testing is still indispensable and complements analytic methods. We focus on fully automated testing techniques including black-box and glass-box test generation as well as runtime assertion checking, which are shown to be effective in an industrial setting.
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