| 1. |
|
|
| 2. |
- Leinonen, V., et al.
(författare)
-
S- F-18 THK-5117-PET and C-11 PIB-PET Imaging in Idiopathic Normal Pressure Hydrocephalus in Relation to Confirmed Amyloid-beta Plaques and Tau in Brain Biopsies
- 2018
-
Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 64:1, s. 171-179
-
Tidskriftsartikel (refereegranskat)abstract
- Background: Detection of pathological tau aggregates could facilitate clinical diagnosis of Alzheimer's disease (AD) and monitor drug effects in clinical trials. S-[F-18] THK-5117 could be a potential tracer to detect pathological tau deposits in brain. However, no previous study have correlated S-[F-18] THK-5117 uptake in PET with brain biopsy verified tau pathology in vivo. Objective: Here we aim to evaluate the association between cerebrospinal fluid (CSF) AD biomarkers, S-[F-18] THK-5117, and [C-11] PIB PET against tau and amyloid lesions in brain biopsy. Methods: Fourteen patients with idiopathic normal pressure hydrocephalus (iNPH) with previous shunt surgery including right frontal cortical brain biopsy and CSF A beta(1-42), total tau, and P-tau(181) measures, underwent brain MRI, [C-11] PIB PET, and S-[F-18] THK-5117 PET imaging. Results: Seven patients had amyloid-beta(A beta, 4G8) plaques, two both A beta and phosphorylated tau (P tau, AT8) and one only P tau in biopsy. As expected, increased brain biopsy A beta was well associated with higher [C-11] PIB uptake in PET. However, S-[F-18] THK-5117 uptake did not show any statistically significant correlation with either brain biopsy P tau or CSF P-tau(181) or total tau. Conclusions: S-[F-18] THK-5117 lacked clear association with neuropathologically verified tau pathology in brain biopsy probably, at least partially, due to off-target binding. Further studies with larger samples of patients with different tau tracers are urgently needed. The detection of simultaneous A beta and tau pathology in iNPH is important since that may indicate poorer and especially shorter response for CSF shunt surgery compared with no pathology.
|
|
| 3. |
- Vilen, ST, et al.
(författare)
-
Intracellular co-localization of trypsin-2 and matrix metalloprotease-9: Possible proteolytic cascade of trypsin-2, MMP-9 and enterokinase in carcinoma
- 2008
-
Ingår i: Experimental Cell Research. - : Elsevier BV. - 1090-2422 .- 0014-4827. ; 314:4, s. 914-926
-
Tidskriftsartikel (refereegranskat)abstract
- Tumor-associated trypsin-2 and matrix metalloprotease-9 (MMP-9) are associated with cancer, particularly with invasive squamous cell carcinomas. They require activation for catalytical competence via proteolytic cascades. One cascade is formed by enterokinase, trypsin-2 and MMP-9; enterokinase activates trypsinogen-2 to trypsin-2, which is an efficient proMMP-9 activator. We describe here that oral squamous cell carcinomas express all members of this cascade: MMP-9, trypsin-2 and enterokinase. The expression of enterokinase in a carcinoma cell line not derived from the duodenum was shown here for the first time. Enterokinase directly cleaved proMMP-9 at the Lys(65)-Ser(66) site, but failed to activate it in vitro. We demonstrated by confocal microscopy that MMP-9 and trypsin-2 co-localized in intracellular vesicles of the carcinoma cells. This co-localization of trypsin-2 and MMP-9 resulted in intracellular proMMP-9 processing that represented fully or partially activated MMP-9. However, although both proteases were present also in various bone tumor tissues, MMP-9 and trypsin-2 never co-localized at the cellular level in these tissues. This suggests that the intracellular vesicular co-localization, storage and possible activation of these proteases may be a unique feature for aggressive epithelial tumors, such as squamous cell carcinomas, but not for tumors of mesenchymal origin.
|
|
| 4. |
|
|
| 5. |
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Koivunen, J., et al.
(författare)
-
PET amyloid ligand [C-11]PIB uptake shows predominantly striatal increase in variant Alzheimer's disease
- 2008
-
Ingår i: Brain. - : Oxford University Press (OUP). - 0006-8950 .- 1460-2156. ; 131:Pt 7, s. 1845-1853
-
Tidskriftsartikel (refereegranskat)abstract
- Variant Alzheimers disease (VarAD) with spastic paraparesis and presenile dementia is associated with certain mutations of the presenilin 1 (PS-1) gene, particularly those leading to deletion of exon 9 (PS-1 E9). VarAD is neuropathologically characterized by the presence of unusually large, A42 positive, non-cored cotton wool plaques (CWPs), also devoid of dystrophic neurites. The aim of the present study was to find out whether [C-11]PIB would show increased uptake and serve as an in vivo biomarker of amyloid accumulation in VarAD. A further aim was to assess the correspondence of the [C-11]PIB binding to the amount and type of A deposits in another group of deceased VarAD patients brains. We studied four patients with VarAD and eight healthy controls with PET using [C-11]PIB as tracer. Parametric images were computed by calculating the region-to-cerebellum and region-to-pons ratio in each voxel over 6090 min. Group differences in [C-11]PIB uptake were analysed with automated region-of-interest (ROI) analysis. [C-11]PIB uptake was compared to the immunohistochemically demonstrated deposition of A in the brains of another group of four deceased VarAD patients. Patients with VarAD had significantly higher [C-11] PIB uptake than the control group in the striatum (caudate nucleus and putamen), anterior and posterior cingulate gyrus, occipital cortex and thalamus. In the caudate and putamen [C-11]PIB uptake, expressed as region-to-cerebellum ratio, was on the average 43 greater than the mean of the control group. The increases in the anterior (28) and posterior (27) cingulate gyrus, occipital cortex (21) and thalamus (14) were smaller. All VarAD patients showed this similar topographical pattern of increased [C-11]PIB uptake. The results were essentially similar when the uptake was expressed as region-to-pons ratios. [C-11]PIB imaging shows increased uptake in patients with VarAD especially in the striatum, and it can be used to detect amyloid accumulation in vivo in these patients. The pattern of increased [C-11]PIB uptake is different from that described in sporadic Alzheimers disease and resembles that seen in Alzheimers disease patients with certain presenilin-1 mutations or amyloid precursor protein gene duplication showing predominantly striatal increase in [C-11]PIB uptake.
|
|
| 9. |
|
|
| 10. |
|
|
| 11. |
|
|
| 12. |
- Golla, Sandeep S V, et al.
(författare)
-
Parametric Binding Images of the TSPO Ligand 18F-DPA-714.
- 2016
-
Ingår i: Journal of Nuclear Medicine. - : Society of Nuclear Medicine. - 0161-5505 .- 1535-5667 .- 2159-662X. ; 57:10, s. 1543-1547
-
Tidskriftsartikel (refereegranskat)abstract
- (18)F-labeled N,N-diethyl-2-(2-[4-(2-fluoroethoxy)phenyl]-5,7-dimethylpyrazolo[1,5-α]pyrimidine-3-yl)acetamide (DPA-714) is a radioligand for the 18-kDa translocator protein. The purpose of the present study was to identify the best method for generating quantitative parametric images of (18)F-DPA-714 binding.METHODS: Ninety-minute dynamic (18)F-DPA-714 PET scans with full arterial sampling from 6 healthy subjects and 9 Alzheimer disease (AD) patients were used. Plasma-input-based Logan graphical analysis and spectral analysis were used to generate parametric volume of distribution (VT) images. Five versions of Ichise, reference Logan, and 2 basis function implementations (receptor parametric mapping and simplified reference tissue model 2 [SRTM2]) of SRTM, all using gray matter cerebellum as the reference region, were applied to generate nondisplaceable binding potential (BPND) images.RESULTS: Plasma-input Logan analysis (r(2) = 0.99; slope, 0.88) and spectral analysis (r(2) = 0.99, slope, 0.93) generated estimates of VT that correlated well with values obtained using nonlinear regression. BPND values generated using SRTM2 (r(2) = 0.83; slope, 0.95) and reference Logan analysis (r(2) = 0.88; slope, 1.01) correlated well with nonlinear regression-based estimates.CONCLUSION: Both Logan analysis and spectral analysis can be used to obtain quantitatively accurate VT images of (18)F-DPA-714. In addition, SRTM2 and reference Logan analysis can provide accurate BPND images. These parametric images could be used for voxel-based comparisons.
|
|
| 13. |
- Golla, Sandeep S V, et al.
(författare)
-
Quantification of [18F]DPA-714 binding in the human brain : initial studies in healthy controls and Alzheimer's disease patients
- 2015
-
Ingår i: Journal of Cerebral Blood Flow and Metabolism. - : SAGE Publications. - 0271-678X .- 1559-7016. ; 35:5, s. 766-772
-
Tidskriftsartikel (refereegranskat)abstract
- Fluorine-18 labelled N,N-diethyl-2-(2-[4-(2-fluoroethoxy)phenyl]-5,7-dimethylpyrazolo[1,5-α]pyrimidine-3-yl)acetamide ([(18)F]DPA-714) binds to the 18-kDa translocator protein (TSPO) with high affinity. The aim of this initial methodological study was to develop a plasma input tracer kinetic model for quantification of [(18)F]DPA-714 binding in healthy subjects and Alzheimer's disease (AD) patients, and to provide a preliminary assessment whether there is a disease-related signal. Ten AD patients and six healthy subjects underwent a dynamic positron emission tomography (PET) study along with arterial sampling and a scan protocol of 150 minutes after administration of 250 ± 10 MBq [(18)F]DPA-714. The model that provided the best fits to tissue time activity curves (TACs) was selected based on Akaike Information Criterion and F-test. The reversible two tissue compartment plasma input model with blood volume parameter was the preferred model for quantification of [(18)F]DPA-714 kinetics, irrespective of scan duration, volume of interest, and underlying volume of distribution (VT). Simplified reference tissue model (SRTM)-derived binding potential (BPND) using cerebellar gray matter as reference tissue correlated well with plasma input-based distribution volume ratio (DVR). These data suggest that [(18)F]DPA-714 cannot be used for separating individual AD patients from healthy subjects, but further studies including TSPO binding status are needed to substantiate these findings.
|
|
| 14. |
|
|
| 15. |
|
|
