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ABSTRACT Objective: The benefit of atropine in pediatric tracheal intubation is not well established. The objective of this study was to evaluate the effect of atropine on the incidence of hypoxemia and bradycardia during tracheal intubations in the pediatric emergency department. Methods: This is a single-center observational study in a tertiary pediatric emergency department. Data were collected on all tracheal intubations in patients from 31 days to incomplete 20 years old, performed between January 2016 and September 2020. Procedures were divided into two groups according to the use or not of atropine as a premedication during intubation. Records with missing data, patients with cardiorespiratory arrest, cyanotic congenital heart diseases, and those with chronic lung diseases with baseline hypoxemia were excluded. The primary outcome was hypoxemia (peripheral oxygen saturation ≤88%), while the secondary outcomes were bradycardia (decrease in heart rate >20% between the maximum and minimum values) and critical bradycardia (heart rate <60 bpm) during intubation procedure. Results: A total of 151 tracheal intubations were identified during the study period, of which 126 were eligible. Of those, 77% had complex, chronic underlying diseases. Atropine was administered to 43 (34.1%) patients and was associated with greater odds of hypoxemia in univariable analysis (OR: 2.62; 95%CI 1.15-6.16; p=0.027) but not in multivariable analysis (OR: 2.07; 95%CI 0.42-10.32; p=0.37). Critical bradycardia occurred in only three patients, being two in the atropine group (p=0.26). Bradycardia was analyzed in only 42 procedures. Atropine use was associated with higher odds of bradycardia in multivariable analysis (OR: 11.00; 95%CI 1.3-92.8; p=0.028). Conclusions: Atropine as a premedication in tracheal intubation did not prevent the occurrence of hypoxemia or bradycardia during intubation procedures in pediatric emergency.

RESUMO Objetivo: Avaliar o efeito da atropina na incidência de hipoxemia e bradicardia durante a intubação orotraqueal no departamento de emergência pediátrica. Métodos: Estudo observacional, realizado em departamento de emergência pediátrica terciário em que foram analisados os registros de intubações orotraqueais de pacientes com 31 dias a 20 anos incompletos, entre janeiro de 2016 e setembro de 2020. Os procedimentos foram divididos em dois grupos de acordo com o uso ou não da atropina como pré-medicação durante a intubação. Foram excluídos os procedimentos com falhas no preenchimento dos dados, pacientes com parada cardiorrespiratória, cardiopatias congênitas cianóticas, e aqueles com pneumopatias crônicas com hipoxemia basal. O desfecho primário foi hipoxemia (saturação periférica de oxigênio ≤88%), enquanto os desfechos secundários foram bradicardia (queda >20% entre a frequência cardíaca máxima e mínima) e bradicardia crítica (frequência cardíaca <60 bpm) durante o procedimento de intubação Resultados: Foram identificados 151 procedimentos de intubação orotraqueal, sendo 126 elegíveis para o estudo. Desses, 77% tinham doenças subjacentes complexas e crônicas. A atropina foi administrada em 43 (34,1%) pacientes e foi associada a maiores chances de hipoxemia na análise univariada (OR: 2,62; IC95% 1,15-6,16; p=0,027), porém, não na análise multivariada (OR: 2,073; IC95% 0,416-10,32; p=0,373). A bradicardia crítica ocorreu em apenas três pacientes, sendo dois no grupo atropina (p=0,268). A bradicardia foi analisada em apenas 42 procedimentos. O uso de atropina foi associado a maior probabilidade de bradicardia (OR: 11,00; IC95% 1,3-92,8; p=0,028) na análise multivariável. Conclusões: Atropina como pré-medicação na intubação orotraqueal não evitou a ocorrência de hipoxemia ou bradicardia durante os procedimentos de intubação na emergência pediátrica.

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The polymorphisms of fatty acid desaturase genes FADS1 and FADS2 have been associated with an increase in weight gain. We investigated FADS1 and FADS2 gene polymorphisms and the relation between ω-3 and ω-6 fatty acid plasma concentrations and gestational weight gain. A prospective cohort study of 199 pregnant women was followed in Santo Antônio de Jesus, Brazil. Plasma levels of polyunsaturated fatty acids (PUFAs) were measured at baseline and gestational weight gain during the first, second, and third trimesters. Fatty acid recognition was carried out with the aid of gas chromatography. Single nucleotide polymorphisms (SNPs) were genotyped using real-time PCR. Statistical analyses included Structural Equation Modelling. A direct effect of FADS1 and FADS2 gene polymorphisms on gestational weight was observed; however, only the SNP rs174575 (FADS2) showed a significant positive direct effect on weight over the course of the pregnancy (0.106; p = 0.016). In terms of the influence of SNPs on plasma levels of PUFAs, it was found that SNP rs174561 (FADS1) and SNP rs174575 (FADS2) showed direct adverse effects on plasma concentrations of ω-3 (eicosapentaenoic acid and alpha-linoleic acid), and only SNP rs174575 had positive direct effects on plasma levels of ARA and the ARA/LA (arachidonic acid/linoleic acid) ratio, ω-6 products, while the SNP rs3834458 (FADS2) had an adverse effect on plasma concentrations of EPA, leading to its increase. Pregnant women who were heterozygous and homozygous for the minor allele of the SNP rs3834458 (FADS2), on the other hand, showed larger concentrations of series ω-3 substrates, which indicates a protective factor for women's health.

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Homeoviscous adaptation in poikilotherms is based in the regulation of the level of desaturation of fatty acids, variation in phospholipids head groups and sterol content in the membrane lipids, in order to maintain the membrane fluidity in response to changes in environmental temperature. Increased proportion of unsaturated fatty acids is thought to be the main response to low-temperature acclimation, which is mostly achieved by fatty acid desaturases. Genome analysis of the ciliate Tetrahymena thermophila and a gene knockout approach has allowed us to identify one Δ12 FAD and to study its activity in the original host and in a yeast heterologous expression system. The "PUFA index" -relative content of polyunsaturated fatty acids compared to the sum of saturated and monounsaturated fatty acid content- was ~57% lower at 15 °C and 35 °C in the Δ12 FAD gene knockout strain (KOΔ12) compared to WT strain. We characterized the role of T. thermophila Δ12 FAD on homeoviscous adaptation and analyzed its involvement in cellular growth, cold stress response, and membrane fluidity, as well as its expression pattern during temperature shifts. Although these alterations allowed normal growth in the KOΔ12 strain at 30 °C or higher temperatures, growth was impaired at temperatures of 20 °C or lower, where homeoviscous adaptation is impaired. These results stress the importance of Δ12 FAD in the regulation of cold adaptation processes, as well as the suitability of T. thermophila as a valuable model to investigate the regulation of membrane lipids and evolutionary conservation and divergence of the underlying mechanisms.

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Experimental evidence has suggested that plasma membrane (PM)-associated signaling and hence cell metabolism and viability depend on lipid composition and organization. The aim of the present work is to develop a cell model to study the endogenous polyunsaturated fatty acids (PUFAs) effect on PM properties and analyze its influence on cholesterol (Chol) homeostasis. We have previously shown that by using a cell line over-expressing stearoyl-CoA-desaturase, membrane composition and organization coordinate cellular pathways involved in Chol efflux and cell viability by different mechanisms. Now, we expanded our studies to a cell model over-expressing both Δ5 and Δ6 desaturases, which resulted in a permanently higher PUFA content in PM. Furthermore, this cell line showed increased PM fluidity, Chol storage, and mitochondrial activity. In addition, human apolipoprotein A-I-mediated Chol removal was less efficient in these cells than in the corresponding control. Taken together, our results suggested that the cell functionality is preserved by regulating PM organization and Chol exportation and homeostasis.

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