Publications by authors named "Valerie Chavez"

Background: The microbial diagnosis of tuberculosis (TB) remains challenging and relies on multiple microbiological tests performed on different clinical specimens. Polymerase chain reactions (PCRs), introduced in the last decades has had a significant impact on the diagnosis of TB. However, questions remain about the use of PCRs in combination with conventional tests for TB, namely microscopy and culture.

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In response to the COVID-19 pandemic, our microbial diagnostic laboratory located in a university hospital has implemented several distinct SARS-CoV-2 RT-PCR systems in a very short time. More than 148,000 tests have been performed over 12 months, which represents about 405 tests per day, with peaks to more than 1,500 tests per days during the second wave. This was only possible thanks to automation and digitalization, to allow high throughput, acceptable time to results and to maintain test reliability.

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Introduction: TL1A (TNFSF15) augments IFN-gamma production by IL-12/IL-18 responsive human T cells. Its ligand, death domain receptor 3 (DR3), is induced by activation on T and NK cells. Although IL-12/IL-18 induces DR3 expression on most NK cells, addition of TL1A minimally increases IFN-gamma production.

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TL1A is a member of the TNF superfamily and its expression is increased in the mucosa of inflammatory bowel disease patients. Neutralizing anti-mouse TL1A Ab attenuates chronic colitis in two T-cell driven murine models, suggesting that TL1A is a central modulator of gut mucosal inflammation in inflammatory bowel disease. We showed previously that TL1A is induced by immune complexes via the Fc gamma R signaling pathway.

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Flap endonuclease 1 (FEN1) proteins, which are present in all kingdoms of life, catalyze the sequence-independent hydrolysis of the bifurcated nucleic acid intermediates formed during DNA replication and repair. How FEN1s have evolved to preferentially cleave flap structures is of great interest especially in light of studies wherein mice carrying a catalytically deficient FEN1 were predisposed to cancer. Structural studies of FEN1s from phage to human have shown that, although they share similar folds, the FEN1s of higher organisms contain a 3'-extrahelical nucleotide (3'-flap) binding pocket.

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Flap endonuclease-1 (FEN-1) is a multifunctional and structure-specific nuclease that plays a critical role in maintaining human genome stability through RNA primer removal, long-patch base excision repair, resolution of DNA secondary structures and stalled DNA replication forks, and apoptotic DNA fragmentation. How FEN-1 is involved in multiple pathways, of which some are seemingly contradictory, is of considerable interest. To date, at least 20 proteins are known to interact with FEN-1; some form distinct complexes that affect one or more FEN-1 activities presumably to direct FEN-1 to a particular DNA metabolic pathway.

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There is much evidence to indicate that FEN-1 efficiently cleaves single-stranded DNA flaps but is unable to process double-stranded flaps or flaps adopting secondary structures. However, the absence of Fen1 in yeast results in a significant increase in trinucleotide repeat (TNR) expansion. There are then two possibilities.

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Coactivator-associated arginine methyltransferase-1 (CARM1) is known to enhance transcriptional activation by nuclear receptors through interactions with the coactivators p160 and cAMP response element binding protein-binding protein (CBP) and methylation of histone H3 at arginine 17 (H3-R17). Here, we show that CARM1 can act as a coactivator for the transcription factor nuclear factor-kappaB (NF-kappaB) and enhance NF-kappaB activity in a CBP (p300)-dependent manner. This enhancement in 293T cells was abolished by cotransfection with a specific short hairpin RNA targeted to knockdown CARM1.

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