| 1. |
- Leinonen, Ville, et al.
(författare)
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Assessment of beta-amyloid in a frontal cortical brain biopsy specimen and by positron emission tomography with carbon 11-labeled Pittsburgh Compound B.
- 2008
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Ingår i: Archives of Neurology. - : American Medical Association (AMA). - 0003-9942 .- 1538-3687. ; 65:10, s. 1304-9
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: To compare carbon 11-labeled Pittsburgh Compound B ([11C]PiB) positron emission tomography (PET) findings in patients with and without Alzheimer disease lesions in frontal cortical biopsy specimens.DESIGN: Cross-sectional study of [11C]PiB PET findings in patients with or without beta-amyloid (Abeta) aggregates in frontal cortical biopsy specimens.SETTING: Two university hospitals in Finland. Patients Ten patients who had undergone intraventricular pressure monitoring with a frontal cortical biopsy (evaluated for Abeta aggregates and hyperphosphorylated tau) for suspected normal-pressure hydrocephalus.INTERVENTIONS: [11C]PiB PET and evaluation for cognitive impairment using a battery of neuropsychological tests.MAIN OUTCOME MEASURES: Immunohistochemical evaluation for Abeta aggregates and hyperphosphorylated tau in the frontal cortical biopsy specimen and [11C]PiB PET.RESULTS: In patients with Abeta aggregates in the frontal cortical biopsy specimen, PET imaging revealed higher [11C]PiB uptake (P < .05) in the frontal, parietal, and lateral temporal cortices and in the striatum as compared with the patients without frontal Abeta deposits.CONCLUSIONS: Our study supports the use of noninvasive [11C]PiB PET in the assessment of Abeta deposition in the brain. Large prospective studies are required to verify whether [11C]PiB PET will be a diagnostic aid, particularly in early Alzheimer disease.
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| 2. |
- Rinne, Juha O., et al.
(författare)
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[C-11]PIB PET Is Associated with the Brain Biopsy Amyloid-beta Load in Subjects Examined for Normal Pressure Hydrocephalus
- 2019
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Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 67:4, s. 1343-1351
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Tidskriftsartikel (refereegranskat)abstract
- Background: Idiopathic normal pressure hydrocephalus (iNPH) is frequently associated with concomitant amyloid-beta (A beta) pathology. Objective: To compare the [C-11]PIB PET uptake in the patients with suspected iNPH to A beta and hyperphosphorylated-tau (HP tau) in the right frontal cortical biopsy, the cerebrospinal fluid (CSF) A beta, the response to a CSF shunt, and the final clinical diagnosis of Alzheimer's disease (AD). Methods: Patients (n = 21) from Kuopio NPH Registry (http://www.uef.fi/nph) with intraventricular pressure monitoring, immunostaining for A beta and HP tau in the right frontal cortical biopsies, and a Mini-Mental State Examination and a Clinical Dementia Rating underwent [C-1(1)]PIB PET. A beta, total tau, and P tau(181) were measured by ELISA from the ventricular (n= 15) and the lumbar (n = 9) CSF. Response to the shunt was seen in 13 out of the 15 shunted patients. AD was diagnosed in 8 patients during a median follow-up of 6 years (mean 7.3 +/- 2.4 years, range 3-1). Results: [C-11]PIB uptake in the right frontal cortex (rho = 0.60, p < 0.01) and the combined neocortical [C-11]PIB uptake score (rho = 0.61, p < 0.01) were associated with a higher A beta load in the right frontal cortical biopsy. Excluding one (1/15) outlier, [C-11]PIB uptake was also associated with the ventricular CSF A beta (rho = -0.58, p = 0.03). Conclusions: The findings show that [C-11]PIB PET can reliably detect simultaneous amyloid pathology among the iNPH patients. Further studies will show whether amyloid PET could predict a clinical response to the shunt operation. In addition, the presence of A beta pathology in the patients with iNPH might also warrant treatment with current AD drugs.
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| 3. |
- Salmi, Juha, et al.
(författare)
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Disentangling the Role of Working Memory in Parkinson's Disease
- 2020
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Ingår i: Frontiers in Aging Neuroscience. - : Frontiers Media S.A.. - 1663-4365 .- 1663-4365. ; 12
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Tidskriftsartikel (refereegranskat)abstract
- Working memory (WM) represents a core cognitive function with a major striatal contribution, and thus WM deficits, commonly observed in Parkinson's disease (PD), could also relate to many other problems in PD patients. Our online study aimed to determine the subdomains of WM that are particularly affected in PD and to clarify the links between WM and everyday cognitive deficits, other executive functions, psychiatric and PD symptoms, as well as early cognitive impairment. Fifty-two mild-to-moderate PD patients and 54 healthy controls performed seven WM tasks tapping selective updating, continuous monitoring, or maintenance of currently active information. Self-ratings of everyday cognition, depression, and apathy symptoms, as well as screenings of global cognitive impairment, were also collected. The data were analyzed using structural equation modeling. Of the three WM domains, only selective updating was directly predictive of PD group membership. More widespread WM deficits were observed only in relation to global cognitive impairment in PD patients. Self-rated everyday cognition or psychiatric symptoms were not linked to WM performance but correlated with each other. Our findings suggest that WM has a rather limited role in the clinical manifestation of PD. Nevertheless, due to its elementary link to striatal function, the updating component of WM could be a candidate for a cognitive marker of PD also in patients who are otherwise cognitively well-preserved.
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| 4. |
- Toppala, Sini, et al.
(författare)
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Midlife Insulin Resistance as a Predictor for Late-Life Cognitive Function and Cerebrovascular Lesions
- 2019
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Ingår i: Journal of Alzheimer's Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 72:1, s. 215-228
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Tidskriftsartikel (refereegranskat)abstract
- Background: Type 2 diabetes (T2DM) increases the risk for Alzheimer’s disease (AD) but not for AD neuropathology. The association between T2DM and AD is assumed to be mediated through vascular mechanisms. However, insulin resistance (IR), the hallmark of T2DM, has been shown to associate with AD neuropathology and cognitive decline.Objective: To evaluate if midlife IR predicts late-life cognitive performance and cerebrovascular lesions (white matter hyperintensities and total vascular burden), and whether cerebrovascular lesions and brain amyloid load are associated with cognitive functioning.Methods: This exposure-to-control follow-up study examined 60 volunteers without dementia (mean age 70.9 years) with neurocognitive testing, brain 3T-MRI and amyloid-PET imaging. The volunteers were recruited from the Finnish Health 2000 survey (n = 6062) to attend follow-up examinations in 2014–2016 according to their insulin sensitivity in 2000 and their APOE genotype. The exposure group (n = 30) had IR in 2000 and the 30 controls had normal insulin sensitivity. There were 15 APOE ɛ4 carriers per group. Statistical analyses were performed with multivariable linear models.Results: At follow-up the IR+group performed worse on executive functions (p = 0.02) and processing speed (p = 0.007) than the IR- group. The groups did not differ in cerebrovascular lesions. No associations were found between cerebrovascular lesions and neurocognitive test scores. Brain amyloid deposition associated with slower processing speed.Conclusion: Midlife IR predicted poorer executive functions and slower processing speed, but not cerebrovascular lesions. Brain amyloid deposition was associated with slower processing speed. The association between midlife IR and late-life cognition might not be mediated through cerebrovascular lesions measured here.
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| 5. |
- Alakurtti, Kati, et al.
(författare)
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Long-term test-retest reliability of striatal and extrastriatal dopamine D-2/3 receptor binding : study with [C-11]raclopride and high-resolution PET
- 2015
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Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 35:7, s. 1199-1205
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Tidskriftsartikel (refereegranskat)abstract
- We measured the long-term test-retest reliability of [C-11]raclopride binding in striatal subregions, the thalamus and the cortex using the bolus-plus-infusion method and a high-resolution positron emission scanner. Seven healthy male volunteers underwent two positron emission tomography (PET) [C-11]raclopride assessments, with a 5-week retest interval. D-2/3 receptor availability was quantified as binding potential using the simplified reference tissue model. Absolute variability (VAR) and intraclass correlation coefficient (ICC) values indicated very good reproducibility for the striatum and were 4.5%/0.82, 3.9%/0.83, and 3.9%/0.82, for the caudate nucleus, putamen, and ventral striatum, respectively. Thalamic reliability was also very good, with VAR of 3.7% and ICC of 0.92. Test-retest data for cortical areas showed good to moderate reproducibility (6.1% to 13.1%). Our results are in line with previous test-retest studies of [C-11]raclopride binding in the striatum. A novel finding is the relatively low variability of [C-11]raclopride binding, providing suggestive evidence that extrastriatal D-2/3 binding can be studied in vivo with [C-11]raclopride PET to be verified in future studies.
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| 6. |
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| 7. |
- Asser, Andres, et al.
(författare)
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Increased striatal VMAT2 binding in mice after chronic administration of methcathinone and manganese
- 2016
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Ingår i: Brain Research. - : Elsevier BV. - 0006-8993 .- 1872-6240. ; 1652, s. 97-102
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Tidskriftsartikel (refereegranskat)abstract
- Intravenous use of a psychostimulant drug containing methcathinone (ephedrone) and manganese causes an irreversible extrapyramidal syndrome in drug abusers. We aimed to reproduce the syndrome in mice to evaluate dopaminergic damage. C57/B6 mice were intraperitoneally injected once a day with the study drug or saline for a period of 27 weeks. Motor activity was recorded in an automated motility-box. After 13 and 27 weeks of treatment, ex vivo digital autoradiography was performed using [C-11]dihydrotetrabenazine ([C-11]DTBZ). After 27 weeks of treatment [C-11]DTBZ autoradiography demonstrated a significant increase in the striatum to -cerebellum binding ratio compared with saline treated controls. At the same time point, there was no evident change in motor activity. Increased [C-11]DTBZ binding may indicate vesicular monoamine transporter type 2 (VMAT2) function is altered. The lack of extrapyramidal symptoms in animals could be attributed to low dosing regimen or high metabolic rate.
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| 8. |
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| 9. |
- Bäckman, Lars, et al.
(författare)
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Effects of working-memory training on striatal dopamine release
- 2011
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 333:6043, s. 718-
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Tidskriftsartikel (refereegranskat)abstract
- Updating of working memory has been associated with striato-frontal brain regions and phasic dopaminergic neurotransmission. We assessed raclopride binding to striatal dopamine (DA) D2 receptors during a letter-updating task and a control condition before and after 5 weeks of updating training. Results showed that updating affected DA activity before training and that training further increased striatal DA release during updating. These findings highlight the pivotal role of transient neural processes associated with D2 receptor activity in working memory.
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| 10. |
- Bäckman, Lars, et al.
(författare)
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Increased dopamine release after working-memory updating training : Neurochemical correlates of transfer
- 2017
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Ingår i: Scientific Reports. - : NATURE PUBLISHING GROUP. - 2045-2322. ; 7
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Tidskriftsartikel (refereegranskat)abstract
- Previous work demonstrates that working-memory (WM) updating training results in improved performance on a letter-memory criterion task, transfers to an untrained n-back task, and increases striatal dopamine (DA) activity during the criterion task. Here, we sought to replicate and extend these findings by also examining neurochemical correlates of transfer. Four positron emission tomography (PET) scans using the radioligand raclopride were performed. Two of these assessed DAD2 binding (letter memory; n-back) before 5 weeks of updating training, and the same two scans were performed post training. Key findings were (a) pronounced training-related behavioral gains in the lettermemory criterion task, (b) altered striatal DAD2 binding potential after training during letter-memory performance, suggesting training-induced increases in DA release, and (c) increased striatal DA activity also during the n-back transfer task after the intervention, but no concomitant behavioral transfer. The fact that the training-related DA alterations during the transfer task were not accompanied by behavioral transfer suggests that increased DA release may be a necessary, but not sufficient, condition for behavioral transfer to occur.
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