Publications by authors named "Andres Christian"

The ubiquitination process plays a crucial role in neuronal differentiation and function. Numerous studies have focused on the expression and functions of E3 ligases during these different stages, far fewer on E2 conjugating enzymes. In mice, as in humans, these E2s belong to 17 conjugating enzyme families.

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Abnormal cytoplasmic aggregates containing the TDP-43 protein and its fragments are present in the central nervous system of the majority of patients with amyotrophic lateral sclerosis (ALS) and in patients with frontotemporal lobar degeneration (FTLD). Many studies have focused on the C-terminal cleavage products of TDP-43 (CTFs), but few have focused on the N-terminal products (NTFs), yet several works and their protein domain composition support the involvement of NTFs in pathophysiology. In the present study, we expressed six NTFs of TDP-43, normally generated in vivo by proteases or following the presence of pathogenic genetic truncating variants, in HEK-293T cells.

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Article Synopsis
  • - Post-translational modifications (PTMs) of proteins significantly impact their function and localization, and changes to these modifications can lead to post-translational variants (PTVs) that are linked to disease processes.
  • - This study focuses on four key proteins related to amyotrophic lateral sclerosis (ALS): SOD1, TDP-43, FUS, and TBK1, detailing their various PTMs like acetylation and phosphorylation, as well as mutation sites relevant to ALS.
  • - Understanding the PTMs and PTVs associated with ALS proteins is essential for gaining insights into the disease's pathology and for creating more effective treatments.
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The occurrence of overweight and obesity among individuals with Autism Spectrum Disorder (ASD) has become a worldwide epidemic. However, there is limited research on this topic in the Lebanese population. Therefore, this study aimed to assess the differences in anthropometric measurements and body composition variables among Lebanese children, pre-adolescents, and adolescents diagnosed with ASD in contrast to typically developing peers across various developmental stages.

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Amyotrophic lateral sclerosis (ALS) is the most common neurodegenerative motor neuron disease and remains misunderstood with a difficult diagnosis and prognosis. The implication of the immune system is recognized in ALS pathophysiology, hence the interest in leucocyte count as lymphocytes and neutrophils. The neutrophil-to-lymphocyte ratio (NLR) has recently been used as a prognosis factor to assess the progression of ALS.

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Central nervous system (CNS) barrier impairment has been reported in amyotrophic lateral sclerosis (ALS), highlighting its potential significance in the disease. In this context, we aim to shed light on its involvement in the disease, by determining albumin quotient (QAlb) at the time of diagnosis of ALS in a large cohort of patients. Patients from the university hospital of Tours ( = 307) were included in this monocentric, retrospective study.

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Autism Spectrum Disorder (ASD) has become a major public health concern due to its rapidly rising incidence over the past few years. Disturbances in folate or methionine metabolism have been identified in many individuals with ASD, suggesting that the folate-methionine cycle may play an essential role in the pathogenesis of autism. Thus, changes in metabolite concentrations associated with this cycle could be used as potential biomarkers and therapeutic targets for ASD.

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Background: Forced vital capacity (FVC) remains difficult to determine for some patients suffering from amyotrophic lateral sclerosis (ALS) due to the rapid progression of the disease. Arterial blood gas (ABG) parameters could represent a valuable alternative. The aim of this study was therefore to evaluate the correlation between ABG parameters and FVC, along with the prognostic ability of ABG parameters, in a large cohort of ALS patients.

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The daily functioning and overall well-being of people with ASD depends largely on understanding how the wider public views ASD. Indeed, an increased level of ASD knowledge in the general population may result in earlier diagnosis, earlier intervention, and better overall outcomes. The present study aimed to examine the current state of ASD knowledge, beliefs, and sources of information in a Lebanese general population sample, to identify the factors that could influence this knowledge.

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Article Synopsis
  • The study investigates the role of the ubiquitin pathway in amyotrophic lateral sclerosis (ALS) by analyzing genes associated with this pathway in 176 ALS patients.
  • Through next-generation sequencing, researchers identified both known and new pathogenic variants in these genes, highlighting the significance of the ubiquitin system in ALS.
  • One notable finding was the role of the NEDL1 gene, which encodes a protein linked to increased cell death and mislocalization of TDP-43, a protein critical to ALS pathology, suggesting a need for further research on NEDL1’s involvement in the disease.
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Article Synopsis
  • There are currently no available biomarkers for diagnosing or predicting Amyotrophic Lateral Sclerosis (ALS) in clinical settings, leading researchers to explore the potential of multiple inflammatory markers, lipids, and apolipoproteins.
  • In a study of 25 ALS patients and 23 controls, various blood tests revealed significant differences, allowing for high accuracy (94%) in distinguishing between the groups using advanced statistical analysis methods.
  • While the predictive accuracy was promising, the study's models could not differentiate between subgroups of ALS patients, highlighting the importance of exploring multiple biological pathways rather than focusing on a single biomarker.
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Amyotrophic lateral sclerosis (ALS) is a devastating neurodegenerative disorder that still lacks an efficient therapy. The barriers between the central nervous system (CNS) and the blood represent a major limiting factor to the development of drugs for CNS diseases, including ALS. Alterations of the blood-brain barrier (BBB) or blood-spinal cord barrier (BSCB) have been reported in this disease but still require further investigations.

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A 16-year-old child with no medical history was admitted to the hospital emergency for abdominal pain associated with polyuria-polydipsia and weight loss (baseline BMI: 25,4 kg/m2). Diagnosis of severe ketoacidosis was quickly raised regarding major metabolic acidosis, high ketonemia and glycemia. Acute pancreatitis was then diagnosed according to a plasmatic lipase more than tenfold normal values associated with a severe hypertriglyceridemia superior to 100 mmol/L.

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Article Synopsis
  • * It involved a comparison between 20 healthy controls and 17 ALS patients, revealing distinct metabolic profiles and specific metabolites like citramalate that could serve as biomarkers for ALS.
  • * The study found global dysfunction in ALS patients' muscles, with notable changes in antioxidant enzyme levels and mitochondrial activity, highlighting potential new avenues for diagnosis and prognosis.
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The ubiquitin pathway regulates the function of many proteins and controls cellular protein homeostasis. In recent years, it has attracted great interest in neurodevelopmental and neurodegenerative diseases. Here, we have presented the first review on the roles of the 9 proteins of the HECT E3 ligase NEDD4 subfamily in the development and function of neurons in the central nervous system (CNS).

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Iron metabolism is tightly linked to infectious and inflammatory signals through hepcidin synthesis. To date, iron homeostasis during SARS-CoV-2 infection has not yet been described. The aim of this study is to characterize the hepcidin and erythroid regulators (growth differentiation factor 15 (GDF-15) and erythroferrone (ERFE)) by measuring concentrations in plasma in context of COVID-19 disease.

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In our previous study, in which array CGH was used on 19 Lebanese ASD subjects and their parents, we identified rare copy number variants (CNVs) in 14 subjects. The five remaining subjects did not show any CNVs related to autism spectrum disorders (ASD). In the present complementary study, we applied whole-exome sequencing (WES), which allows the identification of rare genetic variations such as single nucleotide variations and small insertions/deletions, to the five negative CNV subjects.

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Article Synopsis
  • Research discusses how current global climate models are based on air temperatures but fail to capture the soil temperatures beneath vegetation where many species thrive.
  • New global maps present soil temperature and bioclimatic variables at 1-km resolution for specific depths, revealing that mean annual soil temperatures can differ significantly from air temperatures by up to 10°C.
  • The findings indicate that relying on air temperature could misrepresent climate impacts on ecosystems, especially in colder regions, highlighting the need for more precise soil temperature data for ecological studies.
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Objectives: Trimethylaminuria, also known as Fish Odor Syndrome (FOS), is a condition characterized by the presence of high concentrations of trimethylamine (TMA) in urine, sweat and expired air of affected patients. Diagnosis of this benign but unpleasant disease is mainly based on clinical presentation and assessment of TMA and its metabolite, TMAO (trimethylamine-N-oxide), concentrations in urine of patients.

Material And Methods: We here described the validation of an analytical method for measurement of TMA and TMAO in urine using nuclear magnetic resonance (NMR) according to the specifications of the ISO 15189 norm.

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The aim of this study was to evaluate the kynurenine pathway (KP) and amino acids profile, using mass spectrometry, in the cerebrospinal fluid (CSF) of 42 amyotrophic lateral sclerosis (ALS) patients at the diagnosis and 40 controls to detect early disorders of these pathways. Diagnostic and predictive ability (based on weight loss, forced vital capacity, ALS Functional Rating Scale-Revised evolution over 12 months, and survival time) of these metabolites were evaluated using univariate followed by supervised multivariate analysis. The multivariate model between ALS and controls was not significant but highlighted some KP metabolites (kynurenine (KYN), kynurenic acid (KYNA), 3-Hydroxynurenine (3-HK)/KYNA ratio), and amino acids (Lysine, asparagine) as involved in the discrimination between groups (accuracy 62%).

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Protein aggregates in affected motor neurons are a hallmark of amyotrophic lateral sclerosis (ALS), but the molecular pathways leading to their formation remain incompletely understood. Oxidative stress associated with age, the major risk factor in ALS, contributes to this neurodegeneration in ALS. We show that several genes coding for enzymes of the ubiquitin and small ubiquitin-related modifier (SUMO) pathways exhibit altered expression in motor neuronal cells exposed to oxidative stress, such as the CCNF gene mutated in ALS patients.

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Article Synopsis
  • This study aimed to investigate how the familial clustering and symptoms of ALS (amyotrophic lateral sclerosis) cases could help identify the disease's genetic causes.
  • Researchers analyzed genetic mutations in 235 French families with familial ALS to find connections between genealogy and the disease's characteristics.
  • Findings indicated that specific genetic mutations were linked to the number of affected family generations, suggesting that understanding family history and symptoms could guide targeted genetic testing for ALS.
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Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease caused by the progressive death of both upper and lower motor neurons. The disease presents a poor prognosis, and patients usually die 2-5 years after the onset of symptoms. The hallmark of this disease is the presence of phosphorylated and ubiquitinated aggregates containing trans-active response DNA-binding protein-43 (TDP-43) in the cytoplasm of motor neurons.

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Autism spectrum disorders (ASD) are among the most common childhood neurodevelopmental disorders. Identification of risk and protective factors are necessary to improve the guidance of prevention and intervention strategies. Our study aims to determine the potential risk and protective factors in ASD in the Lebanese population.

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