Molecular Beacon Assay Development for Severe Acute Respiratory Syndrome Coronavirus 2 Detection.

The fast spread of SARS-CoV-2 has led to a global pandemic, calling for fast and accurate assays to allow infection diagnosis and prevention of transmission. We aimed to develop a molecular beacon (MB)-based detection assay for SARS-CoV-2, designed to detect the ORF1ab and S genes, proposing a two-stage COVID-19 testing strategy. The novelty of this work lies in the design and optimization of two MBs for detection of SARS-CoV-2, namely, concentration, fluorescence plateaus of hybridization, reaction temperature and real-time results. We also identify putative G-quadruplex (G4) regions in the genome of SARS-CoV-2. A total of 458 nasopharyngeal and throat swab samples (426 positive and 32 negative) were tested with the MB assay and the fluorescence levels compared with the cycle threshold (Ct) values obtained from a commercial RT-PCR test in terms of test duration, sensitivity, and specificity. Our results show that the samples with higher fluorescence levels correspond to those with low Ct values, suggesting a correlation between viral load and increased MB fluorescence. The proposed assay represents a fast (total duration of 2 h 20 min including amplification and fluorescence reading stages) and simple way of detecting SARS-CoV-2 in clinical samples from the upper respiratory tract.

Intraventricular hemorrhage risk factors in very low birth weight newborns: a case-control study / Fatores de risco para hemorragia intraventricular em recém-nascidos de muito baixo peso: estudo caso-controle

Objective: Identification of variables that affect the risk of severe intraventricular hemorrhage (IVH) in very low birth weight (VLBW) newborns. Methods: Analytic case-control study, in a population consisting of all VLBW newborns admitted to the Neonatal Intensive Care Unit of a maternity hospital, between January 2002 and December 2007. The authors considered as cases all VLBW newborns with severe IVH (grade ? 3), and control all VLBW newborns without IVH. Independent variables included obstetric, perinatal and neonatal diagnosis and therapy. Bivariate analysis and multivariate logistic regression analysis were performed. Results: During this period, of the 864 VLBW newborns admitted to the Neonatal Intensive Care Unit, 9.7% had severe IVH. With bivariate analysis an association between severe IVH, gestational age and birth weight was found. Prenatal care and pre-eclampsia were associated with a decrease in the incidence of severe IVH. Amnionitis, being outborn, vaginal delivery, male gender, intubation in the delivery room, surfactant, hyaline membrane disease, pneumothorax, necrotizing enterocolitis (NEC) perforation and oscillatory high frequency ventilation were associated with an increased incidence of severe IVH. By multivariate logistic regression, the variables associated with increased risk of severe IVH were: pneumothorax (OR = 3.8; 95%CI = 1.7-8.3), NEC with perforation (OR = 8.8; 95%CI = 1.7-45.0), vaginal delivery (OR = 2.0; 95%CI = 1.0-4.1) and high frequency ventilation (OR = 4.8; 95%CI = 1.3-17.3). The following were protective of severe IVH: gestational age (OR = 0.61; 95%CI = 0.52-0.72), patent ductus arteriosus treatment with indomethacin (OR = 0.26; 95%CI = 0.11-0.6) and fertility treatment (OR = 0.24; 95%CI = 0.06-0.94). Conclusion: These data outline the importance of improvement of pre and neonatal care to reduce severe IVH

Objetivo: Identificação de variáveis que influenciem o risco de hemorragia intraventricular (HIV) grave em recém-nascidos de muito baixo peso (RNMBP). Métodos: Efetuou-se um estudo analítico, caso-controle, em uma população constituída por todos os RNMBP admitidos em uma Unidade de Cuidados Intensivos Neonatal (UCIN), no período compreendido entre Janeiro de 2002 e Dezembro de 2007. Consideraram-se casos todos os RNMBP com HIV grave (grau ? 3) e controle todos os RNMBP sem HIV. As variáveis independentes foram dados obstétricos, perinatais, diagnóstico e terapêutica neonatal. Realizou-se análise bivariada e análise de regressão logística multivariada. Resultados: Foram admitidos na Unidade de Cuidados Intensivos Neonatal, neste período, 864 RNMBP, dos quais 9,7% apresentaram HIV grave. Na análise bivariada, verificou-se uma associação entre HIV grave, idade gestacional e peso ao nascer. A atenção pré-natal e pré-eclampsia foram associadas a uma menor incidência de HIV grave. Amnionite, nascimento no exterior, parto vaginal, sexo masculino, intubação na sala de parto, surfactante, doença da membrana hialina, pneumotórax, enterocolite necrotizante (EN) com perfuração e a ventilação de alta frequência oscilatória foram associados a uma maior incidência de HIV grave. No modelo de regressão logística multivariada, as variáveis associadas a um maior risco de HIV grave foram pneumotórax (OR = 3,8; IC95% = 1,7-8,3), EN com perfuração (OR = 8,8; IC95% = 1,7-45,0), parto vaginal (OR = 2,0; IC95% = 1,0-4,1) e ventilação de alta frequência oscilatória (OR = 4,8; IC95% = 1,3-17,3). Foram fatores protetores para HIV grave: idade gestacional (OR = 0,61; IC95% = 0,52-0,72), tratamento da persistência do ducto arterioso com indometacina (OR = 0,26; IC95% = 0,11-0,60) e tratamento de fertilidade (OR = 0,24; IC95% = 0,06-0,94). Conclusão: Os resultados obtidos neste estudo realçam a importância da melhoria da prestação de cuidados pré e neonatais na redução da HIV grave