Publications by authors named "Luis C M Antunes"

Article Synopsis
  • 5-Fluorouracil (5-FU) is commonly used to treat gastrointestinal cancers, but severe toxicity can occur due to exposure factors related to the DPD enzyme, which is influenced by the DPYD gene.
  • A study involving 47 patients assessed their 5-FU plasma levels, DPD activity, and DPYD gene variations to explore possible correlations with toxicity.
  • Results indicated high rates of anemia and neutropenia among patients, with many having plasma levels outside the therapeutic range, suggesting a need for personalized treatment strategies based on DPD assessments to minimize toxicity risks.
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RoundUp (RUp) is a comercial formulation containing glyphosate (N-(phosphono-methyl) glycine), and is the world's leading wide-spectrum herbicide used in agriculture. Supporters of the broad use of glyphosate-based herbicides (GBH) claim they are innocuous to humans, since the active compound acts on the inhibition of enzymes which are absent in human cells. However, the neurotoxic effects of GBH have already been shown in many animal models.

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Humans have a long-standing coexistence with microorganisms. In particular, the microbial community that populates the human gastrointestinal tract has emerged as a critical player in governing human health and disease. DNA and RNA sequencing techniques that map taxonomical composition and genomic potential of the gut community have become invaluable for microbiome research.

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Staphylococcus spp. and Cutibacterium acnes are members of the skin microbiome but can also act as pathogens. Particularly, Staphylococcus species are known to cause medical devices-associated infections, and biofilm production is one of their main virulence factors.

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Humans live in symbiosis with a diverse community of microorganisms, which has evolved to carry out many specific tasks that benefit the host, including protection against invading pathogens. Within the chemical diversity of the gastrointestinal tract, small molecules likely constitute chemical cues for the communication between the microbiota and pathogens. Therefore, we sought to investigate if molecules produced by the human gut microbiota show biological activity against the human pathogen .

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Pseudomonas aeruginosa is one of the most common pathogens related to healthcare-associated infections. The Brazilian isolate, named CCBH4851, is a multidrug-resistant clone belonging to the sequence type 277. The antimicrobial resistance mechanisms of the CCBH4851 strain are associated with the presence of the bla[Formula: see text] gene, encoding a metallo-beta-lactamase, in combination with other exogenously acquired genes.

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The microbiota influences host health through several mechanisms, including protecting it from pathogen colonization. is one of the most frequently found species in the skin microbiota, and its presence can limit the development of pathogens such as causes diverse types of infections ranging from skin abscesses to bloodstream infections. Given the increasing prevalence of drug-resistant strains, it is imperative to search for new strategies for treatment and prevention.

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During the last decades it has become increasingly clear that the microbes that live on and in humans are critical for health. The communities they form, termed microbiomes, are involved in fundamental processes such as the maturation and constant regulation of the immune system. Additionally, they constitute a strong defense barrier to invading pathogens, and are also intricately linked to nutrition.

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Objective: Normally, activation of tropomyosin-related kinase (TRK) receptors by neurotrophins (NTs) stimulates intracellular pathways involved in cell survival and proliferation. Dysregulation of NT/TRK signaling may affect neoplasm prognosis. Data on NT and TRK expression in melanomas are limited, and it is unclear whether NT/TRK signaling pathways are involved in the origin and progression of this neoplasm.

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Violacein is a violet pigment produced by Chromobacterium violaceum that possesses several functions such as antibacterial, antiviral, antifungal, and antioxidant activities. The search for potential compounds and therapies that may interfere with and modulate the gut microbial consortia without causing severe damage and increased resistance is important for the treatment of inflammatory, allergic, and metabolic diseases. The aim of the present work was to evaluate the ability of violacein to change microbial patterns in the mammalian gut by favoring certain groups over the others in order to be used as a therapy for diseases associated with changes in the intestinal microflora.

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Bacteroides fragilis is the most commonly isolated anaerobic bacteria from infectious processes. Several virulence traits contribute to the pathogenic nature of this bacterium, including the ability to tolerate the high concentrations of bile found in the gastrointestinal tract (GIT). The activity of bile salts is similar to detergents and may lead to membrane permeabilization and cell death.

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Background: Worldwide, gastric cancer is the fourth cancer in incidence and the second most common cause of cancer death. Gastric cancer is asymptomatic in the early stages and very often diagnosed at advanced stages, determining a dismal prognosis. Expression of the HER2 gene has been identified in about 20% of gastric cancer cases, and its hyper-expression is associated with poor prognosis.

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Squamous cell carcinoma of the esophagus is a lethal cancer and carries a poor prognosis because of late diagnosis. Identification of molecular markers may aid early diagnosis. We assessed the expression of CDKN2A/RB1 in the esophageal mucosa and its association with the histology.

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We recently showed that Mycobacterium leprae (ML) is able to induce lipid droplet formation in infected macrophages. We herein confirm that cholesterol (Cho) is one of the host lipid molecules that accumulate in ML-infected macrophages and investigate the effects of ML on cellular Cho metabolism responsible for its accumulation. The expression levels of LDL receptors (LDL-R, CD36, SRA-1, SR-B1, and LRP-1) and enzymes involved in Cho biosynthesis were investigated by qRT-PCR and/or Western blot and shown to be higher in lepromatous leprosy (LL) tissues when compared to borderline tuberculoid (BT) lesions.

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Chagas disease is a trypanosomiasis whose causative agent is the protozoan parasite Trypanosoma cruzi, which is transmitted to humans by hematophagous insects known as triatomines and affects a large proportion of South America. The digestive tract of the insect vectors in which T. cruzi develops constitutes a dynamic environment that affects the development of the parasite.

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Aim: To investigate the association between human papillomavirus (HPV) and esophageal squamous cell carcinoma (ESCC) in southern Brazil.

Methods: We studied 189 esophageal samples from 125 patients from three different groups: (1) 102 biopsies from 51 patients with ESCC, with one sample from the tumor and another from normal esophageal mucosa distant from the tumor; (2) 50 esophageal biopsies from 37 patients with a previous diagnosis of head and neck squamous cell carcinoma (HNSCC); and (3) 37 biopsies from esophageal mucosa with normal appearance from 37 dyspeptic patients, not exposed to smoking or alcohol consumption. Nested-polymerase chain reaction (PCR) with the MY09/11 and GP5/6 L1 primers was used to detect HPV L1 in samples fixed in formalin and stored in paraffin blocks.

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Despite considerable efforts over the last decades, our understanding of leprosy pathogenesis remains limited. The complex interplay between pathogens and hosts has profound effects on host metabolism. To explore the metabolic perturbations associated with leprosy, we analyzed the serum metabolome of leprosy patients.

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The Vibrio parahaemolyticus Scr system modulates decisions pertinent to surface colonization by affecting the cellular level of cyclic dimeric GMP (c-di-GMP). In this work, we explore the scope and mechanism of this regulation. Transcriptome comparison of ΔscrABC and wild-type strains revealed expression differences with respect to ∼100 genes.

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The intestinal metabolome is a rich collection of molecules with specialized functions and important physiological effects. Many insults such as enteric infection and microbiota disruption by antibiotics can have profound effects in the metabolic homeostasis of the gut. We have recently shown that Salmonella infection and antibiotic treatment of mice drastically alter the intestinal metabolome.

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Vibrio fischeri quorum sensing involves the LuxI and LuxR proteins. The LuxI protein generates the quorum-sensing signal N-3-oxohexanoyl-l-homoserine lactone (3OC6-HSL), and LuxR is a signal-responsive transcriptional regulator which activates the luminescence (lux) genes and 17 other V. fischeri genes.

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In Vibrio parahaemolyticus, scrC participates in controlling the decision to be a highly mobile swarmer cell or a more adhesive, biofilm-proficient cell type. scrC mutants display decreased swarming motility over surfaces and enhanced capsular polysaccharide production. ScrC is a cytoplasmic membrane protein that contains both GGDEF and EAL conserved protein domains.

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The Vibrio fischeri quorum-sensing signal N-3-oxohexanoyl-l-homoserine lactone (3OC6-HSL) activates expression of the seven-gene luminescence operon. We used microarrays to unveil 18 additional 3OC6-HSL-controlled genes, 3 of which had been identified by other means previously. We show most of these genes are regulated by the 3OC6-HSL-responsive transcriptional regulator LuxR directly.

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Quorum sensing is a density-dependent gene regulation mechanism that has been described in many bacterial species in the last decades. Bacteria that use quorum sensing as part of their gene regulation circuits produce molecules called autoinducers that accumulate in the environment and activate target genes in a quorum-dependent way. Some specific clues led us to hypothesize that Bacteroides species can produce autoinducers and possess a quorum sensing system.

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