A new HPLC technique for the analysis of picomolar amounts of serotonin (5HT) in plasma and cerebrospinal fluid (CSF) is described. Bufotenin is used as internal standard. Detection is achieved electrochemically or fluorimetrically. The detection limit can be estimated as 50 pg 5HT/mL of either fluid (0.3 picomolar). The method is used to characterize a non-particulate pool of 5HT which is clearly distinct of the platelet pool. Administration of parachlorophenylalanine (PCPA) 300 mg/kg to rats leads to a 90% reduction in the plasmatic pool whereas platelet 5HT is only slightly decreased (3rd day after PCPA) or even increased (7th day after PCPA). Human concentration (n = 15) of 5HT in plasma is 2.6 +/- 0.9 ng/mL (X +/- S.D.). The application of the method to CSF of neurological patients reveals 5HT concentrations ranging from 93 to 962 pg/mL.
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Alzheimers Dement (Amst)
January 2025
Introduction: Increasing evidence links amyloid beta (Aβ) aggregation with inflammation. This pilot study investigated the use of an immunoassay panel to map biomarker changes in patients with Alzheimer's disease (AD). Furthermore, we evaluated the stability of protein quantification after multiple freeze-thaw cycles (FTCs).
View Article and Find Full Text PDFAlzheimers Dement (Amst)
January 2025
Background: This study explores the impact of sleep disturbances on gray matter structural covariance networks (SCNs) across the Alzheimer's disease (AD) continuum.
Methods: Amyloid-negative participants served as controls, whereas amyloid positive (A+) individuals were categorized into six groups based on cognitive status and sleep quality. SCNs for the default mode network (DMN), salience network (SN), and executive control network (ECN) were derived from T1-weighted magnetic resonance images.
J Cereb Blood Flow Metab
January 2025
Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden.
Variations in cerebral blood flow and blood volume interact with intracranial pressure and cerebrospinal fluid dynamics, all of which play a crucial role in brain homeostasis. A key physiological modulator is respiration, but its impact on cerebral blood flow and volume has not been thoroughly investigated. Here we used 4D flow MRI in a population-based sample of 65 participants (mean age = 75 ± 1) to quantify these effects.
View Article and Find Full Text PDFCell Tissue Res
January 2025
Departamento de Anatomía e Histología Humana, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain.
Carl C. Speidel (1919) and Ernst Scharrer (1928) were privileged witnesses of the encounter between neurons and hormones, a biological phenomenon that had been occurring in nature during millions of years of evolution, as Berta Scharrer started to unfold since 1935 on. The story of neurosecretion is intimately associated to that of the hypothalamus, such a "marvellous region", as Wolfgang Bargmann (1975) called it.
View Article and Find Full Text PDFNeuro Oncol
January 2025
Department of Neurological Surgery, Keck School of Medicine, University of Southern California.
Background: Leptomeningeal dissemination (LMD) occurs when tumor cells interact with choroid plexus epithelium (CPE) to gain access to cerebrospinal fluid (CSF) in the brain's meninges and ventricular system. This disease is particularly devastating for patients due to our limited understanding and few therapeutic options. The leptomeningeal CSF is a nutritionally deprived microenvironment for tumor cells.
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