Biopolymer-Based Films from Sodium Alginate and Citrus Pectin Reinforced with SiO2

Blend films based on sodium alginate (SA) and citrus pectin (P) reinforced with different concentrations of SiO₂ (0–10% w/w) were developed in this study. From the morphological (SEM) and structural (FT-IR) evaluation, it was verified that the incorporation of the reinforcing agent did not drastically modify the microstructure of the films, nor did new chemical bonds form. However, the XRD results suggested a slight reduction in the crystallinities of the blends by the incorporation of SiO₂. Among the formulations prepared, the addition of a 5% reinforcing agent was responsible for the simultaneous improvement of mechanical and barrier properties. Comparing the control sample (SA/P) with the SA/P/5.0%SiO₂ film, the tensile strength increased from 27.7 ± 3.7 to 40.6 ± 4.5 MPa, and the water-vapor transmission rate decreased from 319.8 ± 38.7 to 288.9 ± 23.5 g m⁻² day⁻¹. Therefore, SiO_2, as a reinforcing agent in SA/P blends, represents a simple and effective strategy for improving the properties of biopolymer-based films in applications, such as packaging.     

Partial inhibition of trypomastigote entry into cultured mammalian cells by monoclonal antibodies against a surface glycoprotein of Trypanosoma cruzi

Monoclonal antibodies were raised against the surface of trypomastigote forms of Trypanosoma cruzi. Although some of these antibodies reacted against antigens shared by trypomastigote and epimastigote or amastigote forms, the majority were trypomastigote-specific. Trypomastigote-specific monoclonal antibodies recognized all infective stages, including trypomastigotes from the bloodstream of infected mice, insect feces, tissue culture and those resulting from differentiation of epimastigotes in axenic culture media. The monoclonal antibodies H1A10 and 6A2, as well as Fab fragments from H1A10, partially prevented T. cruzi invasion of LLC-MK2 cell monolayers (inhibition of 50-70%) when present throughout the entire experiment. Both antibodies recognized an 85 kDa glycoprotein (Tc-85) of the trypomastigote surface which contains N-acetyl-D-glucosamine and/or sialic acid.     

Baixa Concordância entre a Classificação da NYHA e as Variáveis do Teste de Exercício Cardiopulmonar em Pacientes com Insuficiência Cardíaca e Fração de Ejeção Reduzida

BackgroundThe New York Heart Association (NYHA) functional classification is the most commonly used classification system for heart failure (HF), whereas cardiopulmonary exercise testing (CPET) is the gold standard for functional status evaluation in HF.ObjectiveThis study aimed to analyze correlation and concordance between NYHA classes and CPET variables.MethodsHF patients with clinical indication for CPET and ejection fraction (EF) < 50% were selected. Correlation (Spearman coefficient) and concordance (kappa) between NYHA classification and CPET-based classifications were analyzed. A p < 0.05 was accepted as significant.ResultsIn total, 244 patients were included. Mean age was 56 ± 14 years, and mean EF was 35.5% ± 10%. Distribution of patients according to NYHA classification was 31.2%% class I, 48.3% class II, 19.2% class III, and 1.3% class IV. Correlation (r) between NYHA and Weber classes was 0.489 (p < 0.001), and concordance was 0.231 (p < 0.001). Correlation (r) between NYHA and ventilatory classes (minute ventilation/carbon dioxide production [VE/VCO₂] slope) was 0.218 (p < 0.001), and concordance was 0.002 (p = 0.959). Spearman correlation between NYHA and CPET score classes was 0.223 (p = 0.004), and kappa concordance was 0.027 (p = 0.606).ConclusionThere was a moderate association between NYHA and Weber classes, although concordance was low. Ventilatory (VE/VCO₂slope) and CPET score classes had a weak association and a low concordance with NYHA classes.     

Evolução e Estado Atual das Práticas de Implante Transcateter de Válvula Aórtica na América Latina – Estudo WRITTEN LATAM

Background:Transcatheter aortic valve replacement (TAVR) is a worldwide adopted procedure with rapidly evolving practices. Regional and temporal variations are expected to be found.Objective:To compare TAVR practice in Latin America with that around the world and to assess its changes in Latin America from 2015 to 2020.Methods:A survey was applied to global TAVR centers between March and September 2015, and again to Latin-American centers between July 2019 and January 2020. The survey consisted of questions addressing: i) center’s general information; ii) pre-TAVR evaluation; iii) procedural techniques; iv) post-TAVR management; v) follow-up. Answers from the 2015 survey of Latin-American centers (LATAM15) were compared with those of other centers around the world (WORLD15) and with the 2020 updated Latin-American survey (LATAM20). A 5% level of significance was adopted for statistical analysis.Results:250 centers participated in the 2015 survey (LATAM15=29; WORLD15=221) and 46 in the LATAM20. Combined centers experience accounted for 73 707 procedures, with WORLD15 centers performing, on average, 6- and 3-times more procedures than LATAM15 and LATAM20 centers, respectively. LATAM centers performed less minimalistic TAVR than WORLD15 centers, but there was a significant increase in less invasive procedures after 5 years in Latin-American centers. For postprocedural care, a lower period of telemetry and maintenance of temporary pacing wire, along with less utilization of dual antiplatelet therapy was observed in LATAM20 centers.Conclusion:Despite still having a much lower number of procedures, many aspects of TAVR practice in Latin-American centers have evolved in recent years, followingthe trend observed in developed country centers.     

Prevalence and Severity of Sleep Apnea in a Group of Morbidly Obese Patients

Background Obesity is the most important risk factor for obstructive sleep apnea. It is estimated that 70% of sleep apnea patients are obese. In the morbidly obese, the prevalence may reach 80% in men and 50% in women. The aim of this study was to determine the prevalence and severity of sleep apnea in a group of morbidly obese patients, leading to bariatric surgery. Methods In a cross-sectional study developed in Bahia, northeastern Brazil. 108 patients (78 women and 30 men) from the Obesity Treatment and Surgery Center - “Núcleo de Tratamento e Cirurgia da Obesidade” underwent standard polysomnography. Patients with an apnea-hypopnea index (AHI) ≥ 5 events/hour were considered apneic. Results Mean ± SD for age and BMI were 37.1 ± 10.2 years and 45.2 ± 5.4 kg/m2, respectively. The calculated AHI ranged widely from 2.5 to 128.9 events/hour. Sleep apnea was detected in 93.6% of the sample, wherein 35.2% had mild, 30.6% moderate and 27.8% severe apnea. Oxyhemoglobin desaturation was directly related to the AHI and was more severe in men. Conclusion There was a high frequency of sleep apnea in this group of morbidly obese patients, for whom it was very important to request polysomnography, thus enabling therapeutic management and prognostication.     

Rational design of large flat nitrogen-doped graphene oxide quantum dots with green-luminescence suitable for biomedical applications

Rational synthesis and simple methodology for the purification of large (35–45 nm in lateral size) and flat (1.0–1.5 nm of height) nitrogen-doped graphene oxide quantum dots (GOQDs) are presented. The methodology allows robust metal-free and acid-free preparation of N-GOQDs with a yield of about 100% and includes hydrothermal treatment of graphene oxide with hydrogen peroxide and ammonia. It was demonstrated that macroscopic impurities can be separated from N-GOQD suspension by their coagulation with 0.9% NaCl solution. Redispersible in water and saline solutions, particles of N-GOQDs were characterized using tip-enhanced Raman spectroscopy (TERS), photoluminescent, XPS, and UV-VIS spectroscopies. The size and morphology of N-GOQDs were studied by dynamic light scattering, AFM, SEM, and TEM. The procedure proposed allows nitrogen-doped GOQDs to be obtained, having 60–51% of carbon, 34–45% of oxygen, and up to 7.2% of nitrogen. The N-GOQD particles obtained in two hours of synthesis contain only pyrrolic defects of the graphene core. The fraction of pyridine moieties grows with the time of synthesis, while the fraction of quaternary nitrogen declines. Application of TERS allows demonstration that the N-GOQDs consist of a graphene core with an average crystallite size of 9 nm and an average distance between nearest defects smaller than 3 nm. The cytotoxicity tests reveal high viability of the monkey epithelial kidney cells Vero in the presence of N-GOQDs in a concentration below 60 mg L⁻¹. The N-GOQDs demonstrate green luminescence with an emission maximum at 505 nm and sedimentation stability in the cell culture medium.

This paper reveals the methodology for robust preparation of purified nitrogen-doped graphene oxide quantum dots with non-cytotoxic activity against monkey epithelial kidney cells (Vero ATCC® CCL-81™).     

Cadmium Accumulation in Tomato Cultivars and Its Effect on Expression of Metal Transport-Related Genes

Cadmium (Cd) content was quantified in the shoot of six tomato cultivars and the Cd effect on the expression of LeNRAMP3, LeFER, LeIRT1 and LeNRAMP1 was evaluated. The six tomato cultivars accumulated high Cd concentrations and were able to transport Cd to the fruits. Among the evaluated genes, the Cd-induced level of LeFER expression appeared to provide an evidence regarding the capacity of foliar Cd accumulation in tomato. The results indicate that tomato represents a possible pathway for Cd entry into the food chain and an attractive model organism for the elucidation of the mechanisms involved in Cd accumulation.