Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.

BACKGROUND: A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. METHODS: This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. FINDINGS: Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0-75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4-97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8-80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3-4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. INTERPRETATION: ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials. FUNDING: UK Research and Innovation, National Institutes for Health Research (NIHR), Coalition for Epidemic Preparedness Innovations, Bill & Melinda Gates Foundation, Lemann Foundation, Rede D'Or, Brava and Telles Foundation, NIHR Oxford Biomedical Research Centre, Thames Valley and South Midland's NIHR Clinical Research Network, and AstraZeneca

Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK

Background A safe and efficacious vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), if deployed with high coverage, could contribute to the control of the COVID-19 pandemic. We evaluated the safety and efficacy of the ChAdOx1 nCoV-19 vaccine in a pooled interim analysis of four trials. Methods This analysis includes data from four ongoing blinded, randomised, controlled trials done across the UK, Brazil, and South Africa. Participants aged 18 years and older were randomly assigned (1:1) to ChAdOx1 nCoV-19 vaccine or control (meningococcal group A, C, W, and Y conjugate vaccine or saline). Participants in the ChAdOx1 nCoV-19 group received two doses containing 5 × 1010 viral particles (standard dose; SD/SD cohort); a subset in the UK trial received a half dose as their first dose (low dose) and a standard dose as their second dose (LD/SD cohort). The primary efficacy analysis included symptomatic COVID-19 in seronegative participants with a nucleic acid amplification test-positive swab more than 14 days after a second dose of vaccine. Participants were analysed according to treatment received, with data cutoff on Nov 4, 2020. Vaccine efficacy was calculated as 1 - relative risk derived from a robust Poisson regression model adjusted for age. Studies are registered at ISRCTN89951424 and ClinicalTrials.gov, NCT04324606, NCT04400838, and NCT04444674. Findings Between April 23 and Nov 4, 2020, 23 848 participants were enrolled and 11 636 participants (7548 in the UK, 4088 in Brazil) were included in the interim primary efficacy analysis. In participants who received two standard doses, vaccine efficacy was 62·1% (95% CI 41·0–75·7; 27 [0·6%] of 4440 in the ChAdOx1 nCoV-19 group vs71 [1·6%] of 4455 in the control group) and in participants who received a low dose followed by a standard dose, efficacy was 90·0% (67·4–97·0; three [0·2%] of 1367 vs 30 [2·2%] of 1374; pinteraction=0·010). Overall vaccine efficacy across both groups was 70·4% (95·8% CI 54·8–80·6; 30 [0·5%] of 5807 vs 101 [1·7%] of 5829). From 21 days after the first dose, there were ten cases hospitalised for COVID-19, all in the control arm; two were classified as severe COVID-19, including one death. There were 74 341 person-months of safety follow-up (median 3·4 months, IQR 1·3–4·8): 175 severe adverse events occurred in 168 participants, 84 events in the ChAdOx1 nCoV-19 group and 91 in the control group. Three events were classified as possibly related to a vaccine: one in the ChAdOx1 nCoV-19 group, one in the control group, and one in a participant who remains masked to group allocation. Interpretation ChAdOx1 nCoV-19 has an acceptable safety profile and has been found to be efficacious against symptomatic COVID-19 in this interim analysis of ongoing clinical trials

Low alcohol consumption and pregnancy and childhood outcomes: time to change guidelines indicating apparently 'safe' levels of alcohol during pregnancy? A systematic review and meta-analyses.

OBJECTIVES: To determine the effects of low-to-moderate levels of maternal alcohol consumption in pregnancy on pregnancy and longer-term offspring outcomes. SEARCH STRATEGY: Medline, Embase, Web of Science and Psychinfo from inception to 11 July 2016. SELECTION CRITERIA: Prospective observational studies, negative control and quasiexperimental studies of pregnant women estimating effects of light drinking in pregnancy (≤32 g/week) versus abstaining. Pregnancy outcomes such as birth weight and features of fetal alcohol syndrome were examined. DATA COLLECTION AND ANALYSIS: One reviewer extracted data and another checked extracted data. Random effects meta-analyses were performed where applicable, and a narrative summary of findings was carried out otherwise. MAIN RESULTS: 24 cohort and two quasiexperimental studies were included. With the exception of birth size and gestational age, there was insufficient data to meta-analyse or make robust conclusions. Odds of small for gestational age (SGA) and preterm birth were higher for babies whose mothers consumed up to 32 g/week versus none, but estimates for preterm birth were also compatible with no association: summary OR 1.08, 95% CI (1.02 to 1.14), I(2) 0%, (seven studies, all estimates were adjusted) OR 1.10, 95% CI (0.95 to 1.28), I(2) 60%, (nine studies, includes one unadjusted estimates), respectively. The earliest time points of exposure were used in the analysis. CONCLUSION: Evidence of the effects of drinking ≤32 g/week in pregnancy is sparse. As there was some evidence that even light prenatal alcohol consumption is associated with being SGA and preterm delivery, guidance could advise abstention as a precautionary principle but should explain the paucity of evidence

Childhood Outcomes after Hypothermia for Neonatal Encephalopathy

BACKGROUND: We previously reported early results of a randomized trial of whole-body hypothermia for neonatal hypoxic–ischemic encephalopathy showing a significant reduction in the rate of death or moderate or severe disability at 18 to 22 months of age. Long-term outcomes are now available. METHODS: In the original trial, we assigned infants with moderate or severe encephalopathy to usual care (the control group) or whole-body cooling to an esophageal temperature of 33.5°C for 72 hours, followed by slow rewarming (the hypothermia group). We evaluated cognitive, attention and executive, and visuospatial function; neurologic outcomes; and physical and psychosocial health among participants at 6 to 7 years of age. The primary outcome of the present analyses was death or an IQ score below 70. RESULTS: Of the 208 trial participants, primary outcome data were available for 190. Of the 97 children in the hypothermia group and the 93 children in the control group, death or an IQ score below 70 occurred in 46 (47%) and 58 (62%), respectively (P = 0.06); death occurred in 27 (28%) and 41 (44%) (P = 0.04); and death or severe disability occurred in 38 (41%) and 53 (60%) (P = 0.03). Other outcome data were available for the 122 surviving children, 70 in the hypothermia group and 52 in the control group. Moderate or severe disability occurred in 24 of 69 children (35%) and 19 of 50 children (38%), respectively (P = 0.87). Attention–executive dysfunction occurred in 4% and 13%, respectively, of children receiving hypothermia and those receiving usual care (P = 0.19), and visuospatial dysfunction occurred in 4% and 3% (P = 0.80). CONCLUSIONS: The rate of the combined end point of death or an IQ score of less than 70 at 6 to 7 years of age was lower among children undergoing whole-body hypothermia than among those undergoing usual care, but the differences were not significant. However, hypothermia resulted in lower death rates and did not increase rates of severe disability among survivors. (Funded by the National Institutes of Health and the Eunice Kennedy Shriver NICHD Neonatal Research Network; ClinicalTrials.gov number, NCT00005772.

Extreme Preterm Infant Rates of Overweight and Obesity at School Age in the SUPPORT Neuroimaging and Neurodevelopmental Outcomes Cohort

© 2018 Elsevier Inc. Objective: To identify rates of overweight (body mass index [BMI] ≥85th percentile) and obesity (BMI ≥95th percentile) at 6-7 years of age and associated risk factors among extremely preterm infants born at \u3c28 weeks of gestation. Study design: Anthropometrics, blood pressure, and active and sedentary activity levels were prospectively assessed. Three groups were compared, those with a BMI ≥85th percentile (overweight or obese for age, height, and sex) and ≥95th percentile (obese) vs \u3c85th percentile. Multiple regression analyses estimated the relative risks of BMI ≥85th percentile and ≥95th percentile associated with perinatal and early childhood factors. Results: Of 388 children, 22% had a BMI of ≥85th percentile and 10% were obese. Children with obesity and overweight compared with normal weight children had higher body fat (subscapular skinfold and triceps skinfold \u3e85th percentile), central fat (waist circumference \u3e90th percentile), spent more time in sedentary activity (20.5 vs 18.2 vs 16.7 hours/week), and had either systolic and/or diastolic hypertension (24% vs 26% vs 14%), respectively. Postdischarge weight gain velocities from 36 weeks postmenstrual age to 18 months, and 18 months to 6-7 years were independently associated with a BMI of ≥85th percentile, whereas weight gain velocity from 18 months to 6-7 years was associated with obesity. Conclusions: One in 5 former extremely preterm infants is overweight or obese and has central obesity at early school age. Postdischarge weight gain velocities were associated with overweight and obesity. These findings suggest the obesity epidemic is spreading to the most extremely preterm infants. Trial registration: ClinicalTrials.gov: NCT00063063 and NCT0000

Behavioral Deficits at 18-22 Months of Age Are Associated with Early Cerebellar Injury and Cognitive and Language Performance in Children Born Extremely Preterm

© 2018 Elsevier Inc. Objective: To investigate associations in toddlers born extremely preterm (\u3c28 weeks) between neonatal neuroimaging and 18- to 22-month developmental and behavioral outcomes. Study design: Cohort analysis from the Eunice Kennedy Shriver National Institute of Child Health and Human Development Neonatal Research Network Surfactant Positive Airway Pressure and Pulse Oximetry Trial Neuroimaging and Neurodevelopmental Outcomes Study of infants born extremely preterm. Subjects underwent cranial ultrasonography and near-term magnetic resonance imaging (MRI). At 18-22 months of corrected age, the assessment included the Brief Infant Toddler Social Emotional Assessment (BITSEA) Problem and Competence Scale scores and the Bayley Scales of Infant Development, Third Edition (Bayley-III). The BITSEA Problem Scale assesses dysregulation; the Competence Scale assesses social-emotional competence. We examined associations of Problem and Competence scores and positive screen rates with cranial ultrasonography and near-term MRI. Mean BITSEA and Bayley-III scores were compared using ANOVA and positive screen rates with the χ 2 test. We computed correlations between BITSEA and Bayley-III scores. Results: Of the 397 children, positive BITSEA screens were found in 34% for the Problem score and 26% for the Competence score. Presence of lesions on near-term MRI that included cerebellar lesions were significantly associated with lower BITSEA Competence but not with Problem scores; Competence scores were inversely related to the presence/significance of lesions. Positive screens on Competence scores and on both Competence and Problem scores were significantly associated with Bayley-III cognitive and language scores \u3c85 (P \u3c.001). Conclusions: Social–emotional competence contributes to deficits in cognitive and language development. Presence of injury on near-term MRI that includes cerebellar lesions is associated with later social–emotional competence and may be a useful predictor to guide early assessment and intervention. Trial registration: ClinicalTrials.gov: NCT00063063 and NCT00233324