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- De Kort, A. M., et al.
(author)
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Decreased Cerebrospinal Fluid Amyloid beta 38, 40, 42, and 43 Levels in Sporadic and Hereditary Cerebral Amyloid Angiopathy
- 2023
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In: Annals of neurology. - : Wiley. - 0364-5134 .- 1531-8249. ; 93:6, s. 1173-86
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Journal article (peer-reviewed)abstract
- Objective: Vascular amyloid beta (A beta) accumulation is the hallmark of cerebral amyloid angiopathy (CAA). The composition of cerebrospinal fluid (CSF) of CAA patients may serve as a diagnostic biomarker of CAA. We studied the diagnostic potential of the peptides A beta 38, A beta 40, A beta 42, and A beta 43 in patients with sporadic CAA (sCAA), hereditary Dutch-type CAA (D-CAA), and Alzheimer disease (AD).Methods: A beta peptides were quantified by immunoassays in a discovery group (26 patients with sCAA and 40 controls), a validation group (40 patients with sCAA, 40 patients with AD, and 37 controls), and a group of 22 patients with D-CAA and 54 controls. To determine the diagnostic accuracy, the area under the curve (AUC) was calculated using a receiver operating characteristic curve with 95% confidence interval (CI).Results: We found decreased levels of all A beta peptides in sCAA patients and D-CAA patients compared to controls. The difference was most prominent for A beta 42 (AUC of sCAA vs controls for discovery: 0.90, 95% CI = 0.82-0.99; for validation: 0.94, 95% CI = 0.89-0.99) and A beta 43 (AUC of sCAA vs controls for discovery: 0.95, 95% CI = 0.88-1.00; for validation: 0.91, 95% CI = 0.83-1.0). All A beta peptides except A beta 43 were also decreased in sCAA compared to AD (CSF A beta 38: AUC = 0.82, 95% CI = 0.71-0.93; CSF A beta 40: AUC = 0.88, 95% CI = 0.80-0.96; CSF A beta 42: AUC = 0.79, 95% CI = 0.66-0.92).Interpretation: A combined biomarker panel of CSF A beta 38, A beta 40, A beta 42, and A beta 43 has potential to differentiate sCAA from AD and controls, and D-CAA from controls. ANN NEUROL 2023
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- Häggi, C., et al.
(author)
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Negligible Quantities of Particulate Low-Temperature Pyrogenic Carbon Reach the Atlantic Ocean via the Amazon River
- 2021
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In: Global Biogeochemical Cycles. - : American Geophysical Union (AGU). - 0886-6236 .- 1944-9224. ; 35:9
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Journal article (peer-reviewed)abstract
- Particulate pyrogenic carbon (PyC) transported by rivers and aerosols, and deposited in marine sediments, is an important part of the carbon cycle. The chemical composition of PyC is temperature dependent and levoglucosan is a source-specific burning marker used to trace low-temperature PyC. Levoglucosan associated to particulate material has been shown to be preserved during riverine transport and marine deposition in high- and mid-latitudes, but it is yet unknown if this is also the case for (sub)tropical areas, where 90% of global PyC is produced. Here, we investigate transport and deposition of levoglucosan in suspended and riverbed sediments from the Amazon River system and adjacent marine deposition areas. We show that the Amazon River exports negligible amounts of levoglucosan and that concentrations in sediments from the main Amazon tributaries are not related to long-term mean catchment-wide fire activity. Levoglucosan concentrations in marine sediments offshore the Amazon Estuary are positively correlated to total organic content regardless of terrestrial or marine origin, supporting the notion that association of suspended or dissolved PyC to biogenic particles is critical in the preservation of PyC. We estimate that 0.5-10 x 10(6) g yr(-1) of levoglucosan is exported by the Amazon River. This represents only 0.5-10 ppm of the total exported PyC and thereby an insignificant fraction, indicating that riverine derived levoglucosan and low-temperature PyC in the tropics are almost completely degraded before deposition. Hence, we suggest caution in using levoglucosan as tracer for past fire activity in tropical settings near rivers.
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