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| 2. |
- Das, A., et al.
(författare)
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Genomic predictors of response to PD-1 inhibition in children with germline DNA replication repair deficiency
- 2022
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 28:1, s. 125-135
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Tidskriftsartikel (refereegranskat)abstract
- Cancers arising from germline DNA mismatch repair deficiency or polymerase proofreading deficiency (MMRD and PPD) in children harbour the highest mutational and microsatellite insertion–deletion (MS-indel) burden in humans. MMRD and PPD cancers are commonly lethal due to the inherent resistance to chemo-irradiation. Although immune checkpoint inhibitors (ICIs) have failed to benefit children in previous studies, we hypothesized that hypermutation caused by MMRD and PPD will improve outcomes following ICI treatment in these patients. Using an international consortium registry study, we report on the ICI treatment of 45 progressive or recurrent tumors from 38 patients. Durable objective responses were observed in most patients, culminating in a 3 year survival of 41.4%. High mutation burden predicted response for ultra-hypermutant cancers (>100 mutations per Mb) enriched for combined MMRD + PPD, while MS-indels predicted response in MMRD tumors with lower mutation burden (10–100 mutations per Mb). Furthermore, both mechanisms were associated with increased immune infiltration even in ‘immunologically cold’ tumors such as gliomas, contributing to the favorable response. Pseudo-progression (flare) was common and was associated with immune activation in the tumor microenvironment and systemically. Furthermore, patients with flare who continued ICI treatment achieved durable responses. This study demonstrates improved survival for patients with tumors not previously known to respond to ICI treatment, including central nervous system and synchronous cancers, and identifies the dual roles of mutation burden and MS-indels in predicting sustained response to immunotherapy. © 2022, The Author(s).
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| 3. |
- Dickstein, D. L., et al.
(författare)
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Brain and blood biomarkers of tauopathy and neuronal injury in humans and rats with neurobehavioral syndromes following blast exposure
- 2021
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Ingår i: Molecular Psychiatry. - : Springer Science and Business Media LLC. - 1359-4184 .- 1476-5578. ; 26, s. 5940-5954
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Tidskriftsartikel (refereegranskat)abstract
- Traumatic brain injury (TBI) is a risk factor for the later development of neurodegenerative diseases that may have various underlying pathologies. Chronic traumatic encephalopathy (CTE) in particular is associated with repetitive mild TBI (mTBI) and is characterized pathologically by aggregation of hyperphosphorylated tau into neurofibrillary tangles (NFTs). CTE may be suspected when behavior, cognition, and/or memory deteriorate following repetitive mTBI. Exposure to blast overpressure from improvised explosive devices (IEDs) has been implicated as a potential antecedent for CTE amongst Iraq and Afghanistan Warfighters. In this study, we identified biomarker signatures in rats exposed to repetitive low-level blast that develop chronic anxiety-related traits and in human veterans exposed to IED blasts in theater with behavioral, cognitive, and/or memory complaints. Rats exposed to repetitive low-level blasts accumulated abnormal hyperphosphorylated tau in neuronal perikarya and perivascular astroglial processes. Using positron emission tomography (PET) and the [F-18]AV1451 (flortaucipir) tau ligand, we found that five of 10 veterans exhibited excessive retention of [F-18]AV1451 at the white/gray matter junction in frontal, parietal, and temporal brain regions, a typical localization of CTE tauopathy. We also observed elevated levels of neurofilament light (NfL) chain protein in the plasma of veterans displaying excess [F-18]AV1451 retention. These findings suggest an association linking blast injury, tauopathy, and neuronal injury. Further study is required to determine whether clinical, neuroimaging, and/or fluid biomarker signatures can improve the diagnosis of long-term neuropsychiatric sequelae of mTBI.
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| 4. |
- Ossenkoppele, Rik, et al.
(författare)
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Accuracy of Tau Positron Emission Tomography as a Prognostic Marker in Preclinical and Prodromal Alzheimer Disease : A Head-to-Head Comparison against Amyloid Positron Emission Tomography and Magnetic Resonance Imaging
- 2021
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Ingår i: JAMA Neurology. - : American Medical Association (AMA). - 2168-6149. ; 78:8, s. 961-971
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Tidskriftsartikel (refereegranskat)abstract
- Importance: Tau positron emission tomography (PET) tracers have proven useful for the differential diagnosis of dementia, but their utility for predicting cognitive change is unclear. Objective: To examine the prognostic accuracy of baseline fluorine 18 (18F)-flortaucipir and [18F]RO948 (tau) PET in individuals across the Alzheimer disease (AD) clinical spectrum and to perform a head-to-head comparison against established magnetic resonance imaging (MRI) and amyloid PET markers. Design, Setting, and Participants: This prognostic study collected data from 8 cohorts in South Korea, Sweden, and the US from June 1, 2014, to February 28, 2021, with a mean (SD) follow-up of 1.9 (0.8) years. A total of 1431 participants were recruited from memory clinics, clinical trials, or cohort studies; 673 were cognitively unimpaired (CU group; 253 [37.6%] positive for amyloid-β [Aβ]), 443 had mild cognitive impairment (MCI group; 271 [61.2%] positive for Aβ), and 315 had a clinical diagnosis of AD dementia (315 [100%] positive for Aβ). Exposures: [18F]Flortaucipir PET in the discovery cohort (n = 1135) or [18F]RO948 PET in the replication cohort (n = 296), T1-weighted MRI (n = 1431), and amyloid PET (n = 1329) at baseline and repeated Mini-Mental State Examination (MMSE) evaluation. Main Outcomes and Measures: Baseline [18F]flortaucipir/[18F]RO948 PET retention within a temporal region of interest, MRI-based AD-signature cortical thickness, and amyloid PET Centiloids were used to predict changes in MMSE using linear mixed-effects models adjusted for age, sex, education, and cohort. Mediation/interaction analyses tested whether associations between baseline tau PET and cognitive change were mediated by baseline MRI measures and whether age, sex, and APOE genotype modified these associations. Results: Among 1431 participants, the mean (SD) age was 71.2 (8.8) years; 751 (52.5%) were male. Findings for [18F]flortaucipir PET predicted longitudinal changes in MMSE, and effect sizes were stronger than for AD-signature cortical thickness and amyloid PET across all participants (R2, 0.35 [tau PET] vs 0.24 [MRI] vs 0.17 [amyloid PET]; P <.001, bootstrapped for difference) in the Aβ-positive MCI group (R2, 0.25 [tau PET] vs 0.15 [MRI] vs 0.07 [amyloid PET]; P <.001, bootstrapped for difference) and in the Aβ-positive CU group (R2, 0.16 [tau PET] vs 0.08 [MRI] vs 0.08 [amyloid PET]; P <.001, bootstrapped for difference). These findings were replicated in the [18F]RO948 PET cohort. MRI mediated the association between [18F]flortaucipir PET and MMSE in the groups with AD dementia (33.4% [95% CI, 15.5%-60.0%] of the total effect) and Aβ-positive MCI (13.6% [95% CI, 0.0%-28.0%] of the total effect), but not the Aβ-positive CU group (3.7% [95% CI, -17.5% to 39.0%]; P =.71). Age (t = -2.28; P =.02), but not sex (t = 0.92; P =.36) or APOE genotype (t = 1.06; P =.29) modified the association between baseline [18F]flortaucipir PET and cognitive change, such that older individuals showed faster cognitive decline at similar tau PET levels. Conclusions and Relevance: The findings of this prognostic study suggest that tau PET is a promising tool for predicting cognitive change that is superior to amyloid PET and MRI and may support the prognostic process in preclinical and prodromal stages of AD.
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| 5. |
- Ossenkoppele, Rik, et al.
(författare)
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The impact of demographic, clinical, genetic, and imaging variables on tau PET status
- 2021
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 48:7, s. 2245-2258
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: A substantial proportion of amyloid-β (Aβ)+ patients with clinically diagnosed Alzheimer’s disease (AD) dementia and mild cognitive impairment (MCI) are tau PET–negative, while some clinically diagnosed non-AD neurodegenerative disorder (non-AD) patients or cognitively unimpaired (CU) subjects are tau PET–positive. We investigated which demographic, clinical, genetic, and imaging variables contributed to tau PET status. Methods: We included 2338 participants (430 Aβ+ AD dementia, 381 Aβ+ MCI, 370 non-AD, and 1157 CU) who underwent [18F]flortaucipir (n = 1944) or [18F]RO948 (n = 719) PET. Tau PET positivity was determined in the entorhinal cortex, temporal meta-ROI, and Braak V-VI regions using previously established cutoffs. We performed bivariate binary logistic regression models with tau PET status (positive/negative) as dependent variable and age, sex, APOEε4, Aβ status (only in CU and non-AD analyses), MMSE, global white matter hyperintensities (WMH), and AD-signature cortical thickness as predictors. Additionally, we performed multivariable binary logistic regression models to account for all other predictors in the same model. Results: Tau PET positivity in the temporal meta-ROI was 88.6% for AD dementia, 46.5% for MCI, 9.5% for non-AD, and 6.1% for CU. Among Aβ+ participants with AD dementia and MCI, lower age, MMSE score, and AD-signature cortical thickness showed the strongest associations with tau PET positivity. In non-AD and CU participants, presence of Aβ was the strongest predictor of a positive tau PET scan. Conclusion: We identified several demographic, clinical, and neurobiological factors that are important to explain the variance in tau PET retention observed across the AD pathological continuum, non-AD neurodegenerative disorders, and cognitively unimpaired persons.
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| 10. |
- Legg, Lynn A, et al.
(författare)
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Selective serotonin reuptake inhibitors (SSRIs) for stroke recovery
- 2019
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Ingår i: Cochrane Database of Systematic Reviews. - : John Wiley & Sons. - 1469-493X. ; 2019:11
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Forskningsöversikt (refereegranskat)abstract
- BACKGROUND: Stroke is a major cause of adult disability. Selective serotonin reuptake inhibitors (SSRIs) have been used for many years to manage depression and other mood disorders after stroke. The 2012 Cochrane Review of SSRIs for stroke recovery demonstrated positive effects on recovery, even in people who were not depressed at randomisation. A large trial of fluoxetine for stroke recovery (fluoxetine versus placebo under supervision) has recently been published, and it is now appropriate to update the evidence.OBJECTIVES: To determine if SSRIs are more effective than placebo or usual care at improving outcomes in people less than 12 months post-stroke, and to determine whether treatment with SSRIs is associated with adverse effects.SEARCH METHODS: For this update, we searched the Cochrane Stroke Group Trials Register (last searched 16 July 2018), the Cochrane Controlled Trials Register (CENTRAL, Issue 7 of 12, July 2018), MEDLINE (1946 to July 2018), Embase (1974 to July 2018), CINAHL (1982 July 2018), PsycINFO (1985 to July 2018), AMED (1985 to July 2018), and PsycBITE March 2012 to July 2018). We also searched grey literature and clinical trials registers.SELECTION CRITERIA: We included randomised controlled trials (RCTs) that recruited ischaemic or haemorrhagic stroke survivors at any time within the first year. The intervention was any SSRI, given at any dose, for any period, and for any indication. We excluded drugs with mixed pharmacological effects. The comparator was usual care or placebo. To be included, trials had to collect data on at least one of our primary (disability score or independence) or secondary outcomes (impairments, depression, anxiety, quality of life, fatigue, healthcare cost, death, adverse events and leaving the trial early).DATA COLLECTION AND ANALYSIS: We extracted data on demographics, type of stroke, time since stroke, our primary and secondary outcomes, and sources of bias. Two review authors independently extracted data from each trial. We used standardised mean differences (SMDs) to estimate treatment effects for continuous variables, and risk ratios (RRs) for dichotomous effects, with their 95% confidence intervals (CIs). We assessed risks of bias and applied GRADE criteria.MAIN RESULTS: We identified a total of 63 eligible trials recruiting 9168 participants, most of which provided data only at end of treatment and not at follow-up. There was a wide age range. About half the trials required participants to have depression to enter the trial. The duration, drug, and dose varied between trials. Only three of the included trials were at low risk of bias across the key 'Risk of bias' domains. A meta-analysis of these three trials found little or no effect of SSRI on either disability score: SMD -0.01 (95% CI -0.09 to 0.06; P = 0.75; 2 studies, 2829 participants; moderate-quality evidence) or independence: RR 1.00 (95% CI 0.91 to 1.09; P = 0.99; 3 studies, 3249 participants; moderate-quality evidence). We downgraded both these outcomes for imprecision. SSRIs reduced the average depression score (SMD 0.11 lower, 0.19 lower to 0.04 lower; 2 trials, 2861 participants; moderate-quality evidence), but there was a higher observed number of gastrointestinal side effects among participants treated with SSRIs compared to placebo (RR 2.19, 95% CI 1.00 to 4.76; P = 0.05; 2 studies, 148 participants; moderate-quality evidence), with no evidence of heterogeneity (I2 = 0%). For seizures there was no evidence of a substantial difference. When we included all trials in a sensitivity analysis, irrespective of risk of bias, SSRIs appeared to reduce disability scores but not dependence. One large trial (FOCUS) dominated the results. We identified several ongoing trials, including two large trials that together will recruit more than 3000 participants.AUTHORS' CONCLUSIONS: We found no reliable evidence that SSRIs should be used routinely to promote recovery after stroke. Meta-analysis of the trials at low risk of bias indicate that SSRIs do not improve recovery from stroke. We identified potential improvements in disability only in the analyses which included trials at high risk of bias. A further meta-analysis of large ongoing trials will be required to determine the generalisability of these findings.
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| 11. |
- Mead, Gillian E., et al.
(författare)
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Fluoxetine for stroke recovery : Meta-analysis of randomized controlled trials
- 2020
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Ingår i: International Journal of Stroke. - : SAGE Publications. - 1747-4930 .- 1747-4949. ; 15:4, s. 365-376
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To determine whether fluoxetine, at any dose, given within the first year after stroke to patients who did not have to have mood disorders at randomization reduced disability, dependency, neurological deficits and fatigue; improved motor function, mood, and cognition at the end of treatment and follow-up, with the same number or fewer adverse effects.METHODS: Searches (from 2012) in July 2018 included databases, trials registers, reference lists, and contact with experts. Co-primary outcomes were dependence and disability. Dichotomous data were synthesized using risk ratios (RR) and continuous data using standardized mean differences (SMD). Quality was appraised using Cochrane risk of bias methods. Sensitivity analyses explored influence of study quality.RESULTS: The searches identified 3414 references of which 499 full texts were assessed for eligibility. Six new completed RCTs (n = 3710) were eligible, and were added to the seven trials identified in a 2012 Cochrane review (total: 13 trials, n = 4145). There was no difference in the proportion independent (3 trials, n = 3249, 36.6% fluoxetine vs. 36.7% control; RR 1.00, 95% confidence interval 0.91 to 1.09, p = 0.99, I2 = 78%) nor in disability (7 trials n = 3404, SMD 0.05, -0.02 to 0.12 p = 0.15, I2 = 81%) at end of treatment. Fluoxetine was associated with better neurological scores and less depression. Among the four (n = 3283) high-quality RCTs, the only difference between groups was lower depression scores with fluoxetine.CONCLUSION: This class I evidence demonstrates that fluoxetine does not reduce disability and dependency after stroke but improves depression.
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| 12. |
- Montoya, O. D., et al.
(författare)
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On the Power Flow Solution in AC Distribution Networks Using the Laurent’s Series Expansion
- 2021
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Ingår i: 2021 IEEE Texas Power and Energy Conference (TPEC). - : Institute of Electrical and Electronics Engineers (IEEE). ; , s. 1-5
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Konferensbidrag (refereegranskat)abstract
- This paper deals with new power flow formulations for AC distribution networks. The power flow problem is approximated using Laurent’s series expansion method over the product between voltage variables in the power balance equations, which proportionates a mathematical structure similar to the conventional Newton-Raphson method. The proposed model is developed in complex variables, which decreases the number of calculations needed and prevents the transformation of the load flow model into polar coordinates. Numerical results confirm that the proposed method is faster regarding computational time and the total number of iterations required; besides, one of the main advantages of this approach is dealing with radial or mesh grids. All simulations are conducted in the programming environment in MATLAB software.
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| 14. |
- Petrovic, S, et al.
(författare)
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SLC26A7: a basolateral Cl-/HCO3- exchanger specific to intercalated cells of the outer medullary collecting duct
- 2004
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Ingår i: American journal of physiology. Renal physiology. - : American Physiological Society. - 1931-857X .- 1522-1466. ; 286:1, s. F161-F169
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Tidskriftsartikel (refereegranskat)abstract
- The outer medullary collecting duct (OMCD) plays an important role in bicarbonate reabsorption and acid-base regulation. An apical V-type H+-ATPase and a basolateral [Formula: see text] exchanger, located in intercalated cells of OMCD, mediate the bicarbonate reabsorption. Here we report the identification of a new basolateral [Formula: see text] exchanger in OMCD intercalated cells in rat kidney. Northern hybridizations demonstrated the predominant expression of this transporter, also known as SLC26A7, in the outer medulla, with lower expression levels in the inner medulla. SLC26A7 was recognized as a ∼90-kDa band in the outer medulla by immunoblot analysis and was localized on the basolateral membrane of a subset of OMCD cells by immunocytochemical staining. No labeling was detected in the cortex. Double-immunofluorescence labeling with the aquaporin-2 and SLC26A7 antibodies or anion exchanger-1 and SLC26A7 antibodies identified the SLC26A7-expressing cells as α-intercalated cells. Functional studies in oocytes demonstrated that increasing the osmolality of the media (to simulate the physiological milieu in the medulla) increased the [Formula: see text] exchanger activity mediated via SLC26A7 by about threefold ( P < 0.02 vs. normal condition). We propose that SLC26A7 is a basolateral [Formula: see text] exchanger in intercalated cells of the OMCD and may play an important role in bicarbonate reabsorption in medullary collecting duct.
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| 15. |
- Provost, Karine, et al.
(författare)
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Comparing ATN-T designation by tau PET visual reads, tau PET quantification, and CSF PTau181 across three cohorts
- 2021
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Ingår i: European Journal of Nuclear Medicine and Molecular Imaging. - : Springer Science and Business Media LLC. - 1619-7070 .- 1619-7089. ; 48:7, s. 2259-2271
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: To compare rates of tau biomarker positivity (T-status) per the 2018 Alzheimer’s Disease (AD) Research Framework derived from [18F]flortaucipir (FTP) PET visual assessment, FTP quantification, and cerebrospinal fluid (CSF) phosphorylated Tau-181 (PTau181). Methods: We included 351 subjects with varying clinical diagnoses from three cohorts with available FTP PET and CSF PTau181 within 18 months. T-status was derived from (1) FTP visual assessment by two blinded raters; (2) FTP standardized uptake value ratio (SUVR) quantification from a temporal meta-ROI (threshold: SUVR ≥1.27); and (3) Elecsys® Phospho-Tau (181P) CSF (Roche Diagnostics) concentrations (threshold: PTau181 ≥ 24.5 pg/mL). Results: FTP visual reads yielded the highest rates of T+, while T+ by SUVR increased progressively from cognitively normal (CN) through mild cognitive impairment (MCI) and AD dementia. T+ designation by CSF PTau181 was intermediate between FTP visual reads and SUVR values in CN, similar to SUVR in MCI, and lower in AD dementia. Concordance in T-status between modality pairs ranged from 68 to 76% and varied by clinical diagnosis, being highest in patients with AD dementia. In discriminating Aβ + MCI and AD subjects from healthy controls and non-AD participants, FTP visual assessment was most sensitive (0.96) but least specific (0.60). Specificity was highest with FTP SUVR (0.91) with sensitivity of 0.89. Sensitivity (0.73) and specificity (0.72) were balanced for PTau181. Conclusion: The choice of tau biomarker may differ by disease stage and research goals that seek to maximize sensitivity or specificity. Visual interpretations of tau PET enhance sensitivity compared to quantification alone, particularly in early disease stages.
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