RESUMO
Since its emergence in late 2019, coronavirus disease 2019 (COVID-19) has caused millions of deaths and socioeconomic losses. Although vaccination significantly reduced disease mortality, it has been shown that protection wanes over time, and that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants of concern (VOCs) may escape vaccine-derived immunity. Therefore, serological studies are necessary to assess protection in the population and guide vaccine regimens. A common measure of protective immunity is the presence of neutralizing antibodies (nAbs). However, the gold standard for measuring nAbs (plaque reduction neutralization test, or PRNT) is laborious and time-consuming, limiting its large-scale applicability. We developed a high-throughput fluorescence reduction neutralization assay (FRNA) to detect SARS-CoV-2 nAbs. Because the assay relies on immunostaining, we developed and characterized monoclonal antibodies (mAbs) to lower costs and reduce the assay's vulnerability to reagent shortages. Using samples of individuals vaccinated with COVID-19 and unvaccinated/pre-pandemic samples, we showed that FRNA results using commercial and in-house mAbs strongly correlated with those of the PRNT method while providing results in 70% less time. In addition to providing a fast, reliable, and high-throughput alternative for measuring nAbs, the FRNA can be easily customized to assess SARS-CoV-2 VOCs. Additionally, the mAb we produced was able to detect SARS-CoV-2 in pulmonary tissues by immunohistochemistry assays.
Assuntos
COVID-19 , Humanos , Imuno-Histoquímica , COVID-19/diagnóstico , SARS-CoV-2/genética , Anticorpos Antivirais , Anticorpos Monoclonais , Anticorpos NeutralizantesRESUMO
Ribeiro, BG, Morales, AP, Sampaio-Jorge, F, Barth, T, de Oliveira, MBC, Coelho, GMdO, and Leite, TC. Caffeine attenuates decreases in leg power without increased muscle damage. J Strength Cond Res 30(8): 2354-2360, 2016-Caffeine ingestion has been shown to be an effective ergogenic aid in several sports. Caffeine administration may increase exercise capacity, which could lead to a greater degree of muscle damage after exercise. This was a randomized, double-blind, placebo-controlled crossover study. Six male handball athletes ingested placebo (PLA) or caffeine (CAF) (6 mg·kg body mass) capsules on 2 different occasions. Sixty minutes after ingestion of the capsules, serum CAF levels were evaluated. Thereafter, all participants performed a protocol of vertical jumps (VJs). The protocol consisted of 4 sets of 30 seconds of continuous VJs with 60 seconds of recovery between sets. Blood lactate (LAC) and creatine kinase (CK) levels were determined before and after the protocol. We found significant differences in serum CAF levels between PLA (0.09 ± 0.18 µg·ml) vs. CAF (6.59 ± 4.44 µg·ml) (p < 0.001). Caffeine elicited a 5.23% (p ≤ 0.05) improvement in the leg power compared with PLA. The CAF trial displayed higher LAC (p ≤ 0.05) compared with PLA (6.26 ± 2.01 vs. 4.39 ± 2.42 mmol·L, respectively) after protocol of VJs, whereas no difference in CK was observed between trials (p > 0.05). These results indicate that immediate ingestion of CAF (6 mg·kg body weight) can reduce the level of muscle fatigue and preserve leg power during the test, possibly resulting in increase in LAC. There was no increase in muscle damage, which indicates that immediate administration of (6 mg·kg body weight) CAF is safe. Thus, nutritional interventions with CAF could help athletes withstand a greater physiological overload during high-intensity training sessions. The results of this study would be applicable to sports and activities that require repetitive leg power.
Assuntos
Cafeína/administração & dosagem , Estimulantes do Sistema Nervoso Central/administração & dosagem , Exercício Físico/fisiologia , Fadiga Muscular/efeitos dos fármacos , Músculo Esquelético/efeitos dos fármacos , Adulto , Atletas , Cafeína/sangue , Creatina Quinase/sangue , Estudos Cross-Over , Método Duplo-Cego , Humanos , Ácido Láctico/sangue , Perna (Membro)/fisiologia , Masculino , Fadiga Muscular/fisiologia , Força Muscular/efeitos dos fármacos , Força Muscular/fisiologia , Músculo Esquelético/fisiologia , Adulto JovemRESUMO
INTRODUCTION: Body image distortion and/or dissatisfaction may occur primarily due to body fat accumulation and/or distribution. The aim of this study was to evaluate the frequency of body image perception and (dis)satisfaction categories in adult men and women according to the adiposity classification. METHODS: This is a cross-sectional study (n = 514; 33-79 years; 265 women) that is part of a prospective cohort (Pró-Saúde study). Adiposity measurements were determined by two methods: anthropometry, used to calculate the body mass index (BMI) and dual-energy X-ray absorptiometry (DXA), to estimate body fat percentage. Participants were grouped as "no excess adiposity" and "excess adiposity", considering BMI and body fat percentage (>30% for men, >40% for women). Perception and (dis)satisfaction with body image were evaluated using the Kakeshita scale, composed by 15 silhouettes, developed for the Brazilian population. Degree of distortion (perceived BMI - real BMI) and dissatisfaction (perceived BMI - desired BMI) were calculated. RESULTS: A high proportion of men (58.6%; 74.3%), and especially of women (82.6%; 86.8%), presented body size overestimation and dissatisfaction due to excess weight, respectively. A relevant fraction of the women (32.6%) and men (30.8%) who were dissatisfied due to excess weight did not present excess adiposity, especially if classified by DXA. Variability in degree of distortion was hardly explained by anthropometric and DXA variables in women (<5%) and men (â¼22%). Both anthropometric and DXA measurements accounted for â¼30% and â¼50% of the variability in degree of dissatisfaction among women and men, respectively. CONCLUSION: Our results suggest a high frequency of body image distortion in Brazilian adult individuals, as well as dissatisfaction with excess weight, especially among women with excess adiposity. The findings indicate that anthropometric measurements explain much of the variability in degree of body image dissatisfaction in men, with no apparent advantage of the use of more refined DXA measurements.