Reliability of a functional magnetic resonance imaging task of emotional conflict in healthy participants

Task‐based functional neuroimaging methods are increasingly being used to identify biomarkers of treatment response in psychiatric disorders. To facilitate meaningful interpretation of neural correlates of tasks and their potential changes with treatment over time, understanding the reliability of the blood‐oxygen‐level dependent (BOLD) signal of such tasks is essential. We assessed test–retest reliability of an emotional conflict task in healthy participants collected as part of the Canadian Biomarker Integration Network in Depression. Data for 36 participants, scanned at three time points (weeks 0, 2, and 8) were analyzed, and intra‐class correlation coefficients (ICC) were used to quantify reliability. We observed moderate reliability (median ICC values between 0.5 and 0.6), within occipital, parietal, and temporal regions, specifically for conditions of lower cognitive complexity, that is, face, congruent or incongruent trials. For these conditions, activation was also observed within frontal and sub‐cortical regions, however, their reliability was poor (median ICC < 0.2). Clinically relevant prognostic markers based on task‐based fMRI require high predictive accuracy at an individual level. For this to be achieved, reliability of BOLD responses needs to be high. We have shown that reliability of the BOLD response to an emotional conflict task in healthy individuals is moderate. Implications of these findings to further inform studies of treatment effects and biomarker discovery are discussed.     

Assessing the role of nocturnal core body temperature dysregulation as a biomarker of neurodegeneration

The vast majority of patients with idiopathic rapid eye movement sleep behaviour disorder will develop a neurodegenerative α‐synuclein‐related condition, such as Parkinson’s disease or dementia with Lewy bodies. The pathology underlying dream enactment overlaps anatomically with the brainstem regions that regulate circadian core body temperature. Previously, nocturnal core body temperature regulation has been shown to be impaired in Parkinson’s disease. However, no study to date has investigated nocturnal core body temperature changes in patients with idiopathic rapid eye movement sleep behaviour disorder, which may prove to be an early objective biomarker for α‐synucleinopathies. Ten healthy controls, 15 patients with idiopathic rapid eye movement sleep behaviour disorder, 31 patients with Parkinson’s disease and six patients with dementia with Lewy bodies underwent clinical assessment and nocturnal polysomnography with core body temperature monitoring. A validated cosinor method was utilised for core body temperature analysis. No differences in mesor, nadir or time of nadir were observed between groups. However, when compared with healthy controls, the amplitude of the nocturnal core body temperature (mesor minus nadir) was significantly reduced in patients with idiopathic rapid eye movement sleep behaviour disorder, Parkinson’s disease with concurrent rapid eye movement sleep behaviour disorder and dementia with Lewy bodies (p < 0.001, p = 0.043 and p = 0.017, respectively). Importantly, this relationship was not seen in those patients with Parkinson’s disease without rapid eye movement sleep behaviour disorder. In addition, there was a significant negative correlation between amplitude of the core body temperature and self‐reported rapid eye movement sleep behaviour disorder symptoms. Changes in thermoregulatory circadian rhythm may be specifically associated with the pathology underlying rapid eye movement sleep behaviour disorder rather than simply that of α‐synucleinopathy. These findings implicate thermoregulatory dysfunction as a potential early biomarker for development of rapid eye movement sleep behaviour disorder‐associated neurodegeneration, and suggest that subpopulations with differing pathological underpinnings might exist in Parkinson’s disease.     

Inhibition of urinary bladder cancer cell proliferation by silibinin

Silibinin, a natural compound extracted from milk thistle, has demonstrated antitumor properties in urinary bladder cancer cells; however, the role of TP53 gene in these effects is unclear. In order to better understand the molecular and antiproliferative mechanisms of this compound, urinary bladder cancer cells with different TP53 gene status, RT4 (low-grade tumor, wild TP53 gene), 5637 (high-grade tumor, Grade 2, mutated TP53 gene), and T24 (high-grade tumor, Grade 3, mutated TP53 gene) were treated with several concentrations of silibinin (1, 5, 10, 50, 100, and 150 μM). Cytotoxicity, prooxidant effect, morphological changes, cell migration, cell cycle progression, global methylation profile, and relative expression of HOXB3, c-MYC, PLK1, SMAD4, SRC, HAT, HDAC, and RASSF1A genes were evaluated. The silibinin presented cytotoxic and prooxidant effects in the three cell lines. In mutated TP53 cells, significant interference in cell migration and cell cycle arrest at the G2/M phase was observed. Additionally, silibinin induced global DNA hypomethylation in the highest grade tumor cells. For wild-type TP53 cells, a sub-G1 apoptotic population was present. Furthermore, there was modulation of gene expression responsible for cell growth (SMAD and c-MYC), migration (SRC), cell cycle kinetics (PLK1), angiogenesis (HOXB3), and of genes associated with epigenetic events such as DNA acetylation (HAT) and deacetylation (HDAC). In conclusion, the silibinin inhibited the urinary bladder tumor cell proliferation independently of TP53 status; however, cell cycle effects, gene expression changes, and alteration of cell migration are dependent on TP53 status. © 2020 Wiley Periodicals, Inc.     

Evaluation of parasite and host genetics in two generations of a family with Chagas disease

Parasitology Research - Chagas disease, caused by the protozoan Trypanosoma cruzi, is considered to be a multifactorial disease associated with host and parasite genetics, which influence clinical...