Frequency and network analysis of depressive symptoms in patients with cancer compared to the general population

Stress and Psychopatholog

The T1-weighted/T2-weighted ratio as a biomarker of anti-NMDA receptor encephalitis

BACKGROUND: Anti-N-methyl-D-aspartate receptor (NMDAR) encephalitis rarely causes visible lesions in conventional MRI, yet advanced imaging detects extensive white matter damage. To improve prognostic capabilities, we evaluate the T1-weighted/T2-weighted (T1w/T2w) ratio, a measure of white matter integrity computable from clinical MRI sequences, in NMDAR encephalitis and examine its associations with cognitive impairment. METHODS: T1-weighted and T2-weighted MRI were acquired cross-sectionally at 3 Tesla in 53 patients with NMDAR encephalitis (81% women, mean age 29 years) and 53 matched healthy controls. Quantitative and voxel-wise group differences in T1w/T2w ratios and associations with clinical and neuropsychological outcomes were assessed. P-values were false discovery rate (FDR) adjusted where multiple tests were conducted. RESULTS: Patients with NMDAR encephalitis had significantly lower T1w/T2w ratios across normal appearing white matter (p=0.009, Hedges' g=-0.51), which was associated with worse verbal episodic memory performance (r=0.39, p=0.005, p(FDR)=0.026). White matter integrity loss was observed in the corticospinal tract, superior longitudinal fascicle, optic radiation and callosal body with medium to large effects (Cohen's d=[0.42-1.17]). In addition, patients showed decreased T1w/T2w ratios in the hippocampus (p=0.002, p(FDR)=0.005, Hedges' g=-0.62), amygdala (p=0.002, p(FDR)=0.005, Hedges' g=-0.63) and thalamus (p=0.010, p(FDR)=0.019, Hedges' g=-0.51). CONCLUSIONS: The T1w/T2w ratio detects microstructural changes in grey and white matter of patients with NMDAR encephalitis that correlate with cognitive performance. Computable from conventional clinical MRI sequences, this measure shows promise in bridging the clinico-radiological dissociation in NMDAR encephalitis and could serve as an imaging outcome measure in clinical trials

Structural brain changes in patients with post-COVID fatigue: a prospective observational study

BACKGROUND: Post-COVID syndrome is a severe long-term complication of COVID-19. Although fatigue and cognitive complaints are the most prominent symptoms, it is unclear whether they have structural correlates in the brain. We therefore explored the clinical characteristics of post-COVID fatigue, describe associated structural imaging changes, and determine what influences fatigue severity. METHODS: We prospectively recruited 50 patients from neurological post-COVID outpatient clinics (age 18-69 years, 39f/8m) and matched non-COVID healthy controls between April 15 and December 31, 2021. Assessments included diffusion and volumetric MR imaging, neuropsychiatric, and cognitive testing. At 7.5 months (median, IQR 6.5-9.2) after the acute SARS-CoV-2 infection, moderate or severe fatigue was identified in 47/50 patients with post-COVID syndrome who were included in the analyses. As a clinical control group, we included 47 matched multiple sclerosis patients with fatigue. FINDINGS: Our diffusion imaging analyses revealed aberrant fractional anisotropy of the thalamus. Diffusion markers correlated with fatigue severity, such as physical fatigue, fatigue-related impairment in everyday life (Bell score) and daytime sleepiness. Moreover, we observed shape deformations and decreased volumes of the left thalamus, putamen, and pallidum. These overlapped with the more extensive subcortical changes in MS and were associated with impaired short-term memory. While fatigue severity was not related to COVID-19 disease courses (6/47 hospitalised, 2/47 with ICU treatment), post-acute sleep quality and depressiveness emerged as associated factors and were accompanied by increased levels of anxiety and daytime sleepiness. INTERPRETATION: Characteristic structural imaging changes of the thalamus and basal ganglia underlie the persistent fatigue experienced by patients with post-COVID syndrome. Evidence for pathological changes to these subcortical motor and cognitive hubs provides a key to the understanding of post-COVID fatigue and related neuropsychiatric complications. FUNDING: Deutsche Forschungsgemeinschaft (DFG) and German Ministry of Education and Research (BMBF)

Estimating the Quality of Ontology-Based Annotations by Considering Evolutionary Changes

Abstract. Ontology-based annotations associate objects, such as genes and proteins, with well-defined ontology concepts to semantically and uniformly describe object properties. Such annotation mappings are utilized in different applications and analysis studies whose results strongly depend on the quality of the used annotations. To study the quality of annotations we propose a generic evaluation approach considering the annotation generation methods (provenance) as well as the evolution of ontologies, object sources, and annotations. Thus, it facilitates the identification of reliable annotations, e.g., for use in analysis applications. We evaluate our approach for functional protein annotations in Ensembl and Swiss-Prot using the Gene Ontology

Discovering Evolving Regions in Life Science Ontologies

Abstract. Ontologies are heavily used in life sciences and evolve continuously to incorporate new or changed insights. Often ontology changes affect only specific parts (regions) of ontologies making it valuable for ontology users and applications to know the heavily changed regions on the one hand and stable regions on the other hand. However, the size and complexity of life science ontologies renders manual approaches to localize changing or stable regions impossible. We therefore propose an approach to automatically discover evolving or stable ontology regions. We evaluate the approach by studying evolving regions in the Gene Ontology and the NCI Thesaurus

Abscisic-acid and the induction of desiccation tolerance in the extremely xerophilic liverwort Exormotheca holstii

HELLWEGE EM, Dietz K-J, VOLK OH, HARTUNG W. Abscisic-acid and the induction of desiccation tolerance in the extremely xerophilic liverwort Exormotheca holstii. Planta. 1994;194(4):525-531.Abscisic acid (ABA) induces formation of a set of proteins in the xerophilic liverwort Exormotheca holstii. Some of them have immunological properties similar to the dehydrins of desiccated corn embryos and the desiccation-related proteins of Craterosrigma plantagineum. The fluctuations of endogenous ABA during cycles of desiccation and rehydration seem to be sufficiently high to indicate a role for ABA as a stress hormone and thereby as an endogenous inductor of stress-related protein synthesis. Desiccation tolerance disappears when thalli are cultivated for a longer period under well-watered conditions; such thalli are not able to increase stress-dependent ABA biosynthesis sufficiently, or to form the desiccation-related proteins unless they are treated with external ABA. The rehydrated thalli cannot recover from a rapid water loss, while ABA-treated, non-hardened thalli regain their photosynthetic activity within two hours