RESUMO

INTRODUCTION: Uremic toxicity changes the gut structure and permeability, allowing bacterial toxins to translocate from the lumen to the blood during chronic kidney failure (CKD). Clinical fluid overload and tissue edema without uremia have similar effects but have not been adequately demonstrated and analyzed in CKD. AIMS: To investigate the effect of sodium intake on the plasma concentration of gut-derived uremic toxins, indoxyl sulfate (IS), and p-cresyl sulfate (pCS) and the expression of genes and proteins of epithelial gut tight junctions in a rat model of CKD. METHODS: Sham-operated (control group, CG) and five-sixths nephrectomized (5/6Nx) Sprague-Dawley rats were randomly assigned to low (LNa), normal (NNa), or high sodium (HNa) diets., Animals were then sacrificed at 8 and 12 weeks and analyzed for IS and pCS plasma concentrations, as well as for gene and protein expression of thigh junction proteins, and transmission electron microscopy (TEM) in colon fragments. RESULTS: The HNa 5/6Nx groups had higher concentrations of IS and pCS than CG, NNa, and LNa at eight and twelve weeks. Furthermore, HNa 5/6Nx groups had reduced expression of the claudin-4 gene and protein than CG, NNa, and LNa. HNa had reduced occludin gene expression compared to CG. Occludin protein expression was more reduced in HNa than in CG, NNa, and LNa. The gut epithelial tight junctions appear dilated in HNa compared to NNa and LNa in TEM. CONCLUSION: Dietary sodium intake and fluid overload have a significant role in gut epithelial permeability in the CKD model.

Assuntos

Toxinas Bacterianas , Insuficiência Renal Crônica , Sódio na Dieta , Ratos , Animais , Ratos Sprague-Dawley , Ocludina/genética , Ocludina/metabolismo , Junções Íntimas , Toxinas Bacterianas/metabolismo , Indicã , Sódio na Dieta/metabolismo , Permeabilidade

RESUMO

Background: The reference standard for the molecular diagnostic testing for COVID-19 is the use of nasopharyngeal or combined nasopharyngeal and oropharyngeal (NP/OP) swabs. Saliva has been proposed as a minimally invasive specimen whose collection reduces the risks for health care personnel. Objective: To assess the suitability of saliva for COVID-19 diagnosis as a replacement of the reference standard NP/OP swab in the setting of a tertiary care pediatric unit. Study design: A paired study based in the prospective cohort design in patients suspected of having COVID-19. Methods: RT-PCR was used to detect SARS-CoV-2 in paired samples of saliva and NP/OP swab collected from May through August 2020 from 156 pediatric participants, of whom 128 has at least one comorbidity and 91 showed clinical symptoms related to SARS-CoV-2 infection. Additionally, we studied a group of 326 members of the hospital staff, of whom 271 had symptoms related to SARS-CoV-2 infection. Results: In the group of pediatric participants the sensitivity of the diagnostic test in saliva was 82.3% (95% CI 56.6-96.2) and the specificity 95.6% (95% CI 90.8-98.4). The prevalence of COVID-19 was 10.9% (17/156). In 6 of the 23 participants who tested positive for SARS-CoV-2 in at least one specimen type, the virus was detected in saliva but not in NP/OP swab, while in 3 participants the NP/OP swab was positive and saliva negative. In the group of adults, the sensitivity of the test in saliva was 77.8% (95% CI 67.2-86.3) and prevalence 24.8% (81/326). Discordant results between the two types of specimens showed a significant association with low viral load in the pharynx of adults but not of pediatric participants. Interpretation: In the context of a pediatric tertiary care hospital, the sensibility of the test in saliva is not high enough to replace the use of NP/OP swab for COVID-19 diagnosis. Neither NP/OP swab nor saliva could detect all the participants infected with SARS-CoV-2.

RESUMO

Cronobacter sakazakii is an opportunistic foodborne pathogen associated with necrotizing enterocolitis, bacteremia, and meningitis in infants. A comparative proteomic study of C. sakazakii ATCC BAA-894 (CS WT) and a fliF::Tn5 mutant was performed, including the ability of both strains to adhere to and invade N1E-115 cells. To achieve this goal, a nonmotile C. sakazakii‬ ATCC BAA-894 fliF::Tn5 (CS fliF::Tn5) strain was generated using an EZ-Tn5 Tnp Transposome kit. Analysis of differential protein expression showed that 81.49% (361/443) of the proteins were expressed in both strains, 8.35% (37/443) were exclusively expressed in the CS WT strain, and 10.16% (45/443) were exclusively expressed in the CS fliF::Tn5 strain. The main exclusively expressed proteins in the CS WT strain were classified into the "cell motility" and "signal transduction mechanisms" subcategories. The proteins exclusively expressed in the CS fliF::Tn5 strain were classified into the following subcategories: "intracellular trafficking, secretion, and vesicular transport", "replication, recombination, and repair", "nucleotide transport and metabolism", "carbohydrate transport and metabolism", "coenzyme transport and metabolism", and "lipid transport and metabolism". Expression of the Cpa protein was detected in both strains, but Cpa was more abundant in the CS WT strain than in the CS fliF::Tn5 strain. A significant increase (p = 0.0001) in adherence to N1E-115 cells was observed in the nonmotile CS fliF::Tn5 strain (31.3 × 106 CFU/mL) compared to the CS WT strain (14.5 × 106 CFU/mL). Additionally, the CS WT strain showed a 0.17% invasion frequency in N1E-115 cells, which was significantly higher (p = 0.01) than that of the nonmotile CS fliF::Tn5 strain. In conclusion, the proteins involved in the motility were mainly identified by proteomic analysis in the CS WT strain compared to the CS fliF::Tn5 strain. Our data indicate that flagella are required to promote the invasion of N1E-115 cells and that the absence of flagella significantly increases the adherence to N1E-115 cells.

Assuntos

Cronobacter sakazakii , Neuroblastoma , Animais , Cronobacter sakazakii/genética , Camundongos , Proteômica