Neuromelanin-Sensitive Magnetic Resonance Imaging Changes in the Locus Coeruleus/Subcoeruleus Complex in Patients with Typical and Atypical Parkinsonism

Background

The locus coeruleus/subcoeruleus complex (LC/LsC) is a structure comprising melanized noradrenergic neurons.

Objective

To study the LC/LsC damage across Parkinson's disease (PD) and atypical parkinsonism in a large group of subjects.

Methods

We studied 98 healthy control subjects, 47 patients with isolated rapid eye movement sleep behavior disorder (RBD), 75 patients with PD plus RBD, 142 patients with PD without RBD, 19 patients with progressive supranuclear palsy (PSP), and 19 patients with multiple system atrophy (MSA). Twelve patients with MSA had proven RBD. LC/LsC signal intensity was derived from neuromelanin magnetic resonance imaging using automated software.

Results

The signal intensity was reduced in all parkinsonian syndromes compared with healthy control subjects, except in PD without RBD. The signal intensity decreased as age increased. Moreover, the signal intensity was lower in MSA than in isolated RBD and PD without RBD groups. In PD, the signal intensity correlated negatively with the percentage of REM sleep without atonia. There were no differences in signal intensity between PD plus RBD, PSP, and MSA.

Conclusions

Neuromelanin signal intensity was reduced in all parkinsonian disorders, except in PD without RBD. The presence of RBD in parkinsonian disorders appears to be associated with lower neuromelanin signal intensity. Furthermore, lower LC/LsC signal changes in PSP could be partly caused by the effect of age. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.     

Colorimetric Transition of Polydiacetylene/Cyclodextrin Supramolecular Assemblies and Implications as Colorimetric Sensors for Food Phenolic Antioxidants

Molecular self-assembly has significant potential in the field of sensing. Polydiacetylenes (PDAs) are conjugated polymers possessing peculiar optical properties obtained by photopolymerization of self-assembled diacetylene monomers. Herein, the blue-to-red phase transition upon either thermal stimulus or interaction with cyclodextrins (CDs) of two PDAs, bearing either carboxylic (PCDA) or amino (PCDA-NH₂) polar heads, is investigated to develop a colorimetric sensor for food phenolic antioxidants. The change in the PDA polar head does not affect significantly thermo-chromatic transition. Upon thermal stimulus, in both PDAs, color transition occurs straightforward between two distinct stable states and does not involve the disordering of the PDA crystal phase, as revealed by UV–vis spectroscopy and SAXS analysis. Contrarily, PDA/α-CD interaction is influenced by intermolecular forces among PDA polar heads and is more efficient for PCDA. α-CDs presumably cause changes in both PDA backbone conformation and local environment surrounding the individual PDA chains. The PCDA/α-CD assemblies are investigated as colorimetric sensors for the detection of Tyrosol (Ty) and caffeic acid (CAF), by using the principle of competitive inclusion complex formation. The system results to be more sensitive to CAF than Ty and may permit the determination of CAF in concentration ranges suitable for different food products.