Publications by authors named "Samar Nasser Chehimi"

The basolateral amygdala (BLA) assigns valence to sensory stimuli, with a dedicated nociceptive ensemble encoding the negative valence of pain. However, the effects of chronic pain on the transcriptomic signatures and projection architecture of this BLA nociceptive ensemble are not well understood. Here, we show that optogenetic inhibition of the nociceptive BLA ensemble reduces affective-motivational behaviors in chronic neuropathic pain.

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Pain is a dynamic and nonlinear experience shaped by injury and contextual factors, including expectations of future pain or relief. While μ opioid receptors are central to the analgesic effects of opioid drugs, the endogenous opioid neurocircuitry underlying pain and placebo analgesia remains poorly understood. The ventrolateral column of the posterior periaqueductal gray is a critical hub for nociception and endogenous analgesia mediated by opioid signaling.

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Sequencing approaches that allowed for a better resolution of the transcriptome have been a major goal in the transcriptomics field since the development of RNA-seq techniques. While RNA-seq provides gene expression data from one entire sample in bulk, single-cell analysis allows for a better characterization of gene expression associated to specific cell types. Single-cell RNA-seq (scRNA-seq) is a reliable technique to unravel transcriptomic features of the tissues of interest dissociated at a single-cell level.

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Objective: Post-traumatic stress disorder (PTSD) is triggered by traumatic events, but genetic vulnerability and a history of childhood trauma may also increase the risk of PTSD onset. Thus, we investigated the interaction between genetic susceptibility according to polygenic risk score (PRS), and traumatic events.

Methods: We evaluated 68 women with PTSD who had been sexually assaulted and 63 healthy controls with no history of sexual assault.

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The basolateral amygdala (BLA) is essential for assigning positive or negative valence to sensory stimuli. Noxious stimuli that cause pain are encoded by an ensemble of ceptive BLA projection neurons (BLA ensemble). However, the role of the BLA ensemble in mediating behavior changes and the molecular signatures and downstream targets distinguishing this ensemble remain poorly understood.

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Article Synopsis
  • Extracellular vesicles (EVs) play a key role in biological processes like cell communication and contain microRNAs (miRNAs) linked to mental health disorders.* -
  • The study analyzed miRNA expression in serum EVs from 116 adolescents over two time points to compare those with Major Depressive Disorder, Anxiety disorders, and ADHD to those without psychiatric diagnoses.* -
  • While the longitudinal analysis showed no significant results, the cross-sectional findings indicated specific miRNA changes associated with ADHD, MDD, and ANX, highlighting their potential role in mental health. *
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Objective: To report the effectiveness of early molecular diagnosis in the clinical management of rare diseases, presenting 8 patients with 8p23.1DS who have clinical features that overlap the phenotypic spectrum of 22q11.2DS.

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Objectives: Copy Number Variations (CNVs) in the human genome account for common populational variations but can also be responsible for genetic syndromes depending on the affected region. Although a deletion in 5p is responsible for a syndrome with highly recognizable phenotypical features, other chromosomal abnormalities might overlap phenotypes, especially considering that most studies in 5p use traditional cytogenetic techniques and not molecular techniques.

Methods: The authors have investigated 29 patients with clinical suspicion of 5p- syndrome using Chromosomal Microarray (CMA), and have gathered information on previous tests, clinical signs, symptoms, and development of the patients.

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Objective: The purpose of this study was to describe the genomic deoxyribonucleic acid (DNA) methylation profile in fetuses with gastroschisis, determine whether the profile was inherited, and investigate any possible correlations with maternal risk factors.

Method: Genome-wide DNA methylation analysis of 96 blood samples was performed using the Illumina Human Methylation 850K BeadChip. The blood samples were collected as follows: 32 from the umbilical cord of fetuses with gastroschisis, 32 from their respective mothers, 16 from the umbilical cord of fetuses without malformation, and 16 from their respective mothers.

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