Human flap endonuclease structures, DNA double-base flipping, and a unified understanding of the FEN1 superfamily.

Flap endonuclease (FEN1), essential for DNA replication and repair, removes RNA and DNA 5' flaps. FEN1 5' nuclease superfamily members acting in nucleotide excision repair (XPG), mismatch repair (EXO1), and homologous recombination (GEN1) paradoxically incise structurally distinct bubbles, ends, or Holliday junctions, respectively. Here, structural and functional analyses of human FEN1:DNA complexes show structure-specific, sequence-independent recognition for nicked dsDNA bent 100° with unpaired 3' and 5' flaps. Above the active site, a helical cap over a gateway formed by two helices enforces ssDNA threading and specificity for free 5' ends. Crystallographic analyses of product and substrate complexes reveal that dsDNA binding and bending, the ssDNA gateway, and double-base unpairing flanking the scissile phosphate control precise flap incision by the two-metal-ion active site. Superfamily conserved motifs bind and open dsDNA; direct the target region into the helical gateway, permitting only nonbase-paired oligonucleotides active site access; and support a unified understanding of superfamily substrate specificity.

Early-life nutrition is associated with processing speed at age 5 in children born preterm with very low birth weight.

OBJECTIVE: Processing speed is suboptimal among preterm-born children which is of concern as it is a foundational skill supporting higher-level cognitive functions. The study objective was to evaluate associations between early-life nutrition and processing speed in childhood. METHODS: Macronutrient and human milk (mother's own, donor) intakes from 137 children born preterm with very low birth weight enrolled in a nutrition feeding trial were included. Processing speed was evaluated at age 5 using the Wechsler Preschool and Primary Scale of Intelligence-fourth edition Processing Speed Index. Associations between early-life nutrition and processing speed were explored through linear regression. RESULTS: Children had a mean (standard deviation [SD]) birth gestational age of 28.1 (2.5) weeks, weight of 1036 (260) g and 52% were male. The mean (SD) assessment age was 5.7 (0.2) years. Sex-dependent relationships were identified between first postnatal month protein, lipid and energy intakes and processing speed at 5 years. For females, lower protein (per 0.1 g/kg/d: -0.88, 95% confidence interval [CI]: -1.53, -0.23; p = 0.01) and energy (per 10 kcal/kg/d: -2.38, 95% CI: -4.70, -0.05; p = 0.03) intakes were related to higher processing speed scores. Mother's milk provision was positively associated (per 10% increase: 0.80, 95% CI: 0.22, 1.37; p = 0.01) and donor milk was negatively associated (per 10% increase: -1.15, 95% CI: -2.22, -0.08; p = 0.04) with processing speed scores; no sex differences were observed. CONCLUSIONS: First postnatal month nutrition was related to processing speed at age 5 in children born preterm with very low birth weight. Early-life nutrition that supports processing speed may be leveraged to improve later cognitive outcomes for this vulnerable population.

Association of COVID-19 With Major Arterial and Venous Thrombotic Diseases: A Population-Wide Cohort Study of 48 Million Adults in England and Wales.

BACKGROUND: Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) induces a prothrombotic state, but long-term effects of COVID-19 on incidence of vascular diseases are unclear. METHODS: We studied vascular diseases after COVID-19 diagnosis in population-wide anonymized linked English and Welsh electronic health records from January 1 to December 7, 2020. We estimated adjusted hazard ratios comparing the incidence of arterial thromboses and venous thromboembolic events (VTEs) after diagnosis of COVID-19 with the incidence in people without a COVID-19 diagnosis. We conducted subgroup analyses by COVID-19 severity, demographic characteristics, and previous history. RESULTS: Among 48 million adults, 125 985 were hospitalized and 1 319 789 were not hospitalized within 28 days of COVID-19 diagnosis. In England, there were 260 279 first arterial thromboses and 59 421 first VTEs during 41.6 million person-years of follow-up. Adjusted hazard ratios for first arterial thrombosis after COVID-19 diagnosis compared with no COVID-19 diagnosis declined from 21.7 (95% CI, 21.0-22.4) in week 1 after COVID-19 diagnosis to 1.34 (95% CI, 1.21-1.48) during weeks 27 to 49. Adjusted hazard ratios for first VTE after COVID-19 diagnosis declined from 33.2 (95% CI, 31.3-35.2) in week 1 to 1.80 (95% CI, 1.50-2.17) during weeks 27 to 49. Adjusted hazard ratios were higher, for longer after diagnosis, after hospitalized versus nonhospitalized COVID-19, among Black or Asian versus White people, and among people without versus with a previous event. The estimated whole-population increases in risk of arterial thromboses and VTEs 49 weeks after COVID-19 diagnosis were 0.5% and 0.25%, respectively, corresponding to 7200 and 3500 additional events, respectively, after 1.4 million COVID-19 diagnoses. CONCLUSIONS: High relative incidence of vascular events soon after COVID-19 diagnosis declines more rapidly for arterial thromboses than VTEs. However, incidence remains elevated up to 49 weeks after COVID-19 diagnosis. These results support policies to prevent severe COVID-19 by means of COVID-19 vaccines, early review after discharge, risk factor control, and use of secondary preventive agents in high-risk patients.

Amino acid oxidation methods to determine amino acid requirements: do we require lengthy adaptation periods?

Determination of indispensable amino acid (IAA) requirements necessitates a range of intakes of the test IAA and monitoring of the physiological response. Short-term methods are the most feasible for studying multiple intake levels in the same individual. Carbon oxidation methods measure the excretion of 13CO2 in breath from a labelled amino acid (AA) in response to varying intakes of the test AA following a period of adaptation. However, the length of adaptation to each AA intake level has been a source of debate and disagreement among researchers. The assertion of the minimally invasive indicator amino acid oxidation (IAAO) technique is that IAA requirements can be estimated after only a few hours (8 h) of adaptation to each test AA intake, suggesting that adaptation occurs rapidly in response to dietary adjustments. On the contrary, the assertion of most other techniques is that 6-7 d of adaptation is required when determining IAA needs. It has even been argued that a minimum of two weeks is needed to achieve complete adaptation. This review explores evidence regarding AA oxidation methods and whether long periods of adaptation to test IAA levels are necessary when estimating IAA requirements. It was found that the consumption of experimental diets containing lower test IAA intake for greater than 7 d violates the terms of a successful adaptive response. While there is some evidence that short-term 8 h IAAO is not different among different test amino acid intakes up to 7 d, it is unclear whether it impacts assessment of IAA requirements.

Organ Donation in Canadian PICUs: A Cross-Sectional Survey, 2021-2022.

OBJECTIVES: To understand contemporary pediatric organ donation programs in Canadian PICUs, including: policies and practices, data collection and reporting, and system and process barriers. DESIGN: A cross-sectional survey carried out 2021-2022. SETTING: Canadian PICUs affiliated with a donor physician network. SUBJECTS: Pediatric intensivists identified as the donation program lead, or most knowledgeable about donation for their institution. MEASUREMENTS AND MAIN RESULTS: A 19-item survey was developed through collaboration with stakeholders from the organ donation and transplantation community within Canada. Domains and items were generated and reduced iteratively during an in-person workshop. Pretesting and pilot testing were completed to ensure readability, flow, clinical sensibility, and construct validity. Fifteen of 16 (94%) invited Canadian PICUs from seven provinces completed the survey representing 88% (15/18) of all noncardiac Canadian PICUs. Surveys were completed between June 2021 and September 2022. All units support donation after death by neurologic criteria (DNC); 14 of 15 indicated donation policies were in place and 1 of 15 indicated no policy but the ability to facilitate donation. Thirteen of 15 units (87%) support donation after death by circulatory criteria (DCC) with policies in place, with 11 of 13 of these indicating routine support of donation opportunities. The majority (13/15) of units identified a donation champion. Of the 16 identified champions across these centers, 13 were physicians and were registered nurses or nurse practitioners. Eight of 13 units (62%) with donation champions had positions supported financially, of which 5 units came from the Organ Donation Organization and the other 3 came from the provincial health authority. Finally, only 3 of 15 PICU donation programs have a pediatric donation committee with family involvement. Variability exists in identification (including determination of death practices), referral, and approach for donation between units. CONCLUSIONS: Although all Canadian PICUs support donation after DNC donation, and most support donation after DCC, variability exists in the identification, referral, and approach of potential donors. There is a notable lack of family involvement in pediatric donation programs. There are many opportunities for standardization of PICU donation programs which may result in improved rates of pediatric organ donation in Canada.

Breastfeeding and human milk in the NICU: From birth to discharge.

It is well recognized that human milk is the optimal nutritive source for all infants, including those requiring intensive care. This statement reviews evidence supporting the importance of breastfeeding and human milk for infants, and why breastfeeding practices should be prioritized in the neonatal intensive care unit (NICU). It also reviews how to optimally feed infants based on their stability and maturity, and how to support mothers to establish and maintain milk production when their infants are unable to feed at the breast.

Metabolic acidosis during continuous glucagon therapy for neonatal hypoglycemia.

Objectives: Refractory neonatal hypoglycemia may be treated with glucagon infusions, which have been associated with thrombocytopenia and hyponatremia. After anecdotally noting metabolic acidosis during glucagon therapy in our hospital, an outcome not previously reported in the literature, we aimed to quantify occurrence of metabolic acidosis (base excess >-6) as well as thrombocytopenia and hyponatremia during treatment with glucagon. Methods: We performed a single-centre retrospective case series. Descriptive statistics were used and subgroups compared with Chi-Square, Fisher's Exact Test, and Mann-Whitney U testing. Results: Sixty-two infants (mean birth gestational age 37.2 weeks, 64.5% male) were treated with continuous glucagon infusions for median 10 days during the study period. 41.2% were preterm, 21.0% were small for gestational age, and 30.6% were infants of diabetic mothers. Metabolic acidosis was seen in 59.6% and was more common in infants who were not born to diabetic mothers (75% versus 24% in infants of diabetic mothers, P<0.001). Infants with versus without metabolic acidosis had lower birth weights (median 2,743 g versus 3,854 g, P<0.01) and were treated with higher doses of glucagon (0.02 versus 0.01 mg/kg/h, P<0.01) for a longer duration (12.4 versus 5.9 days, P<0.01). Thrombocytopenia was diagnosed in 51.9% of patients. Conclusions: In addition to thrombocytopenia, metabolic acidosis of unclear etiology appears to be very common with glucagon infusions for neonatal hypoglycemia, especially in lower birth weight infants or those born to mothers without diabetes. Further research is needed to elucidate causation and potential mechanisms.

Metabolic Availability of Methionine Assessed Using Indicator Amino Acid Oxidation Method, Is Greater when Cooked Lentils and Steamed Rice Are Combined in the Diet of Healthy Young Men.

BACKGROUND: Lentil is considered a high protein source. However, it is low in sulphur amino acids (SAA) and their metabolic availability (MA) is further affected by antinutritional factors in lentils. The combination of lentils with grains such as rice can enhance the protein quality of a lentil-based meal but the MA of SAA in lentils must first be known. OBJECTIVES: The objectives of the current study were to assess the MA of methionine in lentils and to test the effects of consumption of complementing lentils with rice in young adults. METHODS: Five healthy young men [age <30 y, BMI <25 (in kg/m2)] were each studied at 8 or 10 intake amounts of methionine in random order; 4 daily intake amounts of l-methionine: 0.5, 1, 2, and 3 mg.kg-1.d-1 (reference diet), 3 daily intake amounts of methionine from lentils, and 3 daily intake amounts of the mixed meal of lentils + rice (test diets). The MA of methionine and the effects of complementation were assessed by comparing the indicator amino acid oxidation (IAAO) response to varying intakes of methionine in cooked Canadian lentils, and in rice + lentils combined, compared with the IAAO response to l-methionine intakes in the reference protein (crystalline AA mixture patterned after egg protein) using the slope ratio method. l-[1-13C] phenylalanine was used as the indicator. Data were analyzed using the procedure "MIXED" with subject as a random variable, and oxidation day as repeated measure. RESULTS: The MA of methionine from lentils was 69%. Complementation of cooked lentils with rice decreased the oxidation of l-[1-13C] phenylalanine by up to 16% (P < 0.05). CONCLUSIONS: The content and MA of methionine are low in lentils. However, combination of lentils with rice in a 1:1 ratio can improve the protein quality of lentil-based diets, resulting in increased protein synthesis in young healthy adults. This trial was registered at www.clinical trials.gov as NCT03110913.

An online international comparison of palliative care identification in primary care using the Surprise Question.

BACKGROUND: The Surprise Question ('Would I be surprised if this patient died within 12 months?') identifies patients in the last year of life. It is unclear if 'surprised' means the same for each clinician, and whether their responses are internally consistent. AIM: To determine the consistency with which the Surprise Question is used. DESIGN: A cross-sectional online study of participants located in Belgium, Germany, Italy, The Netherlands, Switzerland and UK. Participants completed 20 hypothetical patient summaries ('vignettes'). Primary outcome measure: continuous estimate of probability of death within 12 months (0% [certain survival]-100% [certain death]). A threshold (probability estimate above which Surprise Question responses were consistently 'no') and an inconsistency range (range of probability estimates where respondents vacillated between responses) were calculated. Univariable and multivariable linear regression explored differences in consistency. Trial registration: NCT03697213. SETTING/PARTICIPANTS: Registered General Practitioners (GPs). Of the 307 GPs who started the study, 250 completed 15 or more vignettes. RESULTS: Participants had a consistency threshold of 49.8% (SD 22.7) and inconsistency range of 17% (SD 22.4). Italy had a significantly higher threshold than other countries (p = 0.002). There was also a difference in threshold levels depending on age of clinician, for every yearly increase, participants had a higher threshold. There was no difference in inconsistency between countries (p = 0.53). CONCLUSIONS: There is variation between clinicians regarding the use of the Surprise Question. Over half of GPs were not internally consistent in their responses to the Surprise Question. Future research with standardised terms and real patients is warranted.

Magnetic resonance imaging of neonatal hemochromatosis.

Neonatal hemochromatosis is a rare condition that causes neonatal liver failure, frequently resulting in fetal loss or neonatal death. It is thought that most cases of neonatal hemochromatosis are caused by gestational alloimmune liver disease (GALD), with neonatal hemochromatosis being a phenotype of GALD rather than a disease process. Extrahepatic siderosis in the pancreas, myocardium, thyroid and minor salivary gland is a characteristic feature of neonatal hemochromatosis. There is also sparing of the reticuloendothelial system with no iron deposition in the spleen. Hepatic and extrahepatic siderosis seen in neonatal hemochromatosis is from iron dysregulation secondary to liver damage rather than iron deposition causing the liver damage. The presence of extrahepatic siderosis in the pancreas and thyroid is diagnostic of neonatal hemochromatosis and can be detected noninvasively by multi-echo gradient recalled echo (GRE) T2*-weighted sequence of MRI within hours of birth. This helps to expedite the treatment in the form of intravenous immunoglobulin and exchange transfusion, which improves the survival in these babies. The finding of hepatic siderosis is nonspecific and does not help in the diagnosis of neonatal hemochromatosis because it is seen with other causes of advanced liver disease.

Neonatal Piglets Can Synthesize Adequate Creatine, but Only with Sufficient Dietary Arginine and Methionine, or with Guanidinoacetate and Excess Methionine.

BACKGROUND: Suckling piglets synthesize most of their creatine requirement, which consumes substantial amounts of arginine in order to synthesize guanidinoacetic acid (GAA) and methionine in order to transmethylate GAA to creatine. OBJECTIVES: To determine whether supplemental GAA or creatine spare arginine and/or methionine for protein synthesis and, if GAA is supplemented, whether excess methionine is needed for conversion to creatine. METHODS: Yucatan miniature piglets (9-11 days old; both sexes) were fed 1 of 5 elemental diets for 5 days: 1) low arginine (0.3 g·kg-1·d-1) and low methionine (0.20 g·kg-1·d-1; Base); 2) Base plus GAA (0.093 g·kg-1·d-1; +GAA); 3) Base plus GAA plus excess methionine (0.5 g·kg-1·d-1; +GAA/Met); 4) Base plus creatine (0.12 g·kg-1·d-1; +Cre); or 5) excess arginine (1.8 g·kg-1·d-1) and excess methionine (+Arg/Met). Isotope tracers were infused to determine whole-body GAA, creatine, and protein synthesis; tissues were analyzed for creatine synthesis enzymes and metabolite concentrations. Data were analyzed by 1-way ANOVA. RESULTS: : GAA and creatine syntheses were 115% and 32% higher, respectively, with the +Arg/Met diet (P < 0.0001), in spite of 33% lower renal L-arginine: glycine amidinotransferase activity (P < 0.0001) compared to Base, suggesting substrate availability dictates synthesis rather than enzyme capacity. GAA or creatine supplementation reduced arginine conversion to creatine by 46% and 43%, respectively (P < 0.01), but did not spare amino acids for whole-body protein synthesis, suggesting that limited amino acids were diverted to protein at the expense of creatine synthesis. The +GAA/Met diet led to higher creatine concentrations in the kidney (2.6-fold) and liver (7.6-fold) than the +GAA diet (P < 0.01), suggesting excess methionine is needed for GAA conversion to creatine. CONCLUSIONS: Piglets are capable of synthesizing sufficient creatine from the precursor amino acids arginine and methionine, or from GAA plus methionine.

Each Additional Day of Antibiotics Is Associated With Lower Gut Anaerobes in Neonatal Intensive Care Unit Patients.

BACKGROUND: Discontinuation of inappropriate antimicrobial therapy is an important target for stewardship intervention. The drug and duration-dependent effects of antibiotics on the developing neonatal gut microbiota needs to be precisely quantified. METHODS: In this retrospective, cross-sectional study, we performed 16S rRNA sequencing on stool swab samples collected from neonatal intensive care unit patients within 7 days of discontinuation of therapy who received ampicillin and tobramycin (AT), ampicillin and cefotaxime (AC), or ampicillin, tobramycin, and metronidazole (ATM). We compared taxonomic composition within term and preterm infant groups between treatment regimens. We calculated adjusted effect estimates for antibiotic type and duration of therapy on the richness of obligate anaerobes and known butyrate-producers in all infants. RESULTS: A total of 72 infants were included in the study. Term infants received AT (20/28; 71%) or AC (8/28; 29%) with median durations of 3 and 3.5 days, respectively. Preterm infants received AT (32/44; 73%) or ATM (12/44; 27%) with median durations of 4 and 7 days, respectively. Compositional analyses of 67 stool swab samples demonstrated low diversity and dominance by potential pathogens. Within 1 week of discontinuation of therapy, each additional day of antibiotics was associated with lower richness of obligate anaerobes (adjusted risk ratio [aRR], 0.84; 95% confidence interval [CI], .73-.95) and butyrate-producers (aRR, 0.82; 95% CI, .67-.97). CONCLUSIONS: Each additional day of antibiotics was associated with lower richness of anaerobes and butyrate-producers within 1 week after therapy. A longitudinally sampled cohort with preexposure sampling is needed to validate our results.

Bioavailable Methionine Assessed Using the Indicator Amino Acid Oxidation Method Is Greater When Cooked Chickpeas and Steamed Rice Are Combined in Healthy Young Men.

BACKGROUND: In general, pulse protein is limiting in the indispensable amino acid methionine, and antinutritional factors in pulses can affect methionine bioavailability. Complementation with grains such as rice can improve pulse protein quality, but knowledge of methionine bioavailability in pulses and grains is necessary to correct for available methionine when planning and assessing dietary protein intake. OBJECTIVES: The study objectives were to determine the bioavailability of methionine in rice and chickpeas separately and to assess the effect of complementation of chickpeas and rice. METHODS: Eleven healthy young men (<30 y, BMI <25 kg/m2) were studied in a repeated-measures design using the indicator amino acid oxidation (IAAO) method, with l-[1-13C]phenylalanine as the indicator. Each received 7 or 10 methionine intakes in random order: 4 intakes of l-methionine-0.5, 1, 2, and 3 mg⋅kg-1⋅d-1 (reference diet); 3 intakes of methionine from rice and from chickpeas; and 3 intakes from the mixed meal of chickpeas plus rice (test diets). The bioavailability of methionine and the effect of complementation were assessed by comparing the IAAO response to varying intakes of methionine in rice, in cooked Canadian chickpeas, and in rice plus chickpeas combined compared with the IAAO response to l-methionine intakes in the reference protein (crystalline amino acid mixture patterned after egg protein) using the slope ratio method. RESULTS: The bioavailability of methionine from rice and from chickpeas was 100% and 63%, respectively. Complementation of cooked chickpeas with rice decreased the oxidation of l-[1-13C]phenylalanine by up to 14% (P < 0.05), suggesting an improved protein quality of the combined chickpeas plus rice protein. CONCLUSIONS: When chickpeas are the main protein source in the diet of young adult men, the combination of rice and chickpeas in a 3:1 ratio is recommended to improve dietary protein quality. This trial was registered at clinicaltrials.gov as NCT03339154 and NCT03674736.

Online training improves medical students' ability to recognise when a person is dying: The ORaClES randomised controlled trial.

BACKGROUND: Recognising dying is a key clinical skill for doctors, yet there is little training. AIM: To assess the effectiveness of an online training resource designed to enhance medical students' ability to recognise dying. DESIGN: Online multicentre double-blind randomised controlled trial (NCT03360812). The training resource for the intervention group was developed from a group of expert palliative care doctors' weightings of various signs/symptoms to recognise dying. The control group received no training. SETTING/PARTICIPANTS: Participants were senior UK medical students. They reviewed 92 patient summaries and provided a probability of death within 72 hours (0% certain survival - 100% certain death) pre, post, and 2 weeks after the training. Primary outcome: (1) Mean Absolute Difference (MAD) score between participants' and the experts' scores, immediately post intervention. Secondary outcomes: (2) weight attributed to each factor, (3) learning effect and (4) level of expertise (Cochran-Weiss-Shanteau (CWS)). RESULTS: Out of 168 participants, 135 completed the trial (80%); 66 received the intervention (49%). After using the training resource, the intervention group had better agreement with the experts in their survival estimates (δMAD = -3.43, 95% CI -0.11 to -0.34, p = <0.001) and weighting of clinical factors. There was no learning effect of the MAD scores at the 2-week time point (δMAD = 1.50, 95% CI -0.87 to 3.86, p = 0.21). At the 2-week time point, the intervention group was statistically more expert in their decision-making versus controls (intervention CWS = 146.04 (SD 140.21), control CWS = 110.75 (SD 104.05); p = 0.01). CONCLUSION: The online training resource proved effective in altering the decision-making of medical students to agree more with expert decision-making.

Correction to: An online international comparison of thresholds for triggering a negative response to the "Surprise Question": a study protocol.

Following publication of the original article [1], an error in reference 18 was reported.

Sport Preparticipation Screening for Asymptomatic Atlantoaxial Instability in Patients With Down Syndrome.

Down syndrome (DS) is a clinical syndrome comprising typical facial features and various physical and intellectual disabilities due to extra genetic material on chromosome 21, with one in every 1000 babies born in the United Kingdom affected. Patients with Down syndrome are at risk of atlantoaxial instability (AAI). Although AAI can occur in other conditions, such as rheumatoid arthritis, this position statement deals specifically with patients with DS and asymptomatic AAI. Atlantoaxial instability, also referred to as atlantoaxial subluxation, is defined as increased movement between the first (atlas) and second (axial) cervical vertebra joint articulation, the atlantoaxial joint. Atlantoaxial instability is reported to occur in 6.8% to 27% of the DS population, although this varies depending on the age of the patients whom you are screening. Less than 1% to 2% of these patients are then thought to later develop symptomatic AAI, although the natural history and progression of AAI is not well understood. The risks associated with AAI are neurological injury from excessive movement of the cervical vertebra impinging on and then damaging the spinal cord, although the risk of this during sporting activities is extremely rare. Clearly, physical activity and sports participation for patients with DS has many biological, psychological, and social benefits, and the Faculty of Sport and Exercise Medicine (FSEM), United Kingdom, wishes to promote safe physical activity and sport for all. The FSEM, United Kingdom, has therefore produced a statement regarding sport preparticipation screening for asymptomatic AAI in patients with DS.

Tryptophan Requirement in School-Age Children Determined by the Indicator Amino Acid Oxidation Method is Similar to Current Recommendations.

BACKGROUND: The requirement for dietary tryptophan in school-age children has never been empirically derived. OBJECTIVE: The objective of our study was to determine the tryptophan requirement of school-age children using the indicator amino acid oxidation technique. METHODS: Volunteer healthy school-age children, between 8 and 12 y, were enrolled and the oxidation of l-[13C]-phenylalanine to 13CO2 measured in response to graded intakes of dietary tryptophan. Seven children (3 boys, 4 girls) participated in the study and received randomly assigned tryptophan intakes ranging from 0.5 to 9.75 mg.kg-1.d-1 for a total of 36 studies. The diets provided energy at 1.5 times each subject's resting energy expenditure and were isocaloric. Protein was provided as an amino acid mixture on the basis of the egg protein pattern, and phenylalanine and tyrosine were maintained constant across the protein intake concentrations at 25 and 40 mg.kg-1.d-1. All subjects were adapted for 2 d before the study day to a protein intake of 1.5 g.kg-1.d-1. The mean tryptophan requirement was determined by applying a mixed-effect change-point regression analysis to F13CO2 (label tracer oxidation in 13CO2 breath) which identified a breakpoint in the F13CO2 in response to graded amounts of tryptophan. RESULTS: The mean [estimated average requirement (EAR)] and upper 95% CI, (approximating the RDA) of tryptophan requirements were estimated to be 4.7 and 6.1 mg.kg-1.d-1, respectively. CONCLUSION: Our results are similar to the current recommended EAR and RDA of 5 and 6 mg.kg-1.d-1 for healthy growing children based on the factorial calculation. Clinical Trials Registration No. NCT02018588.

An online international comparison of thresholds for triggering a negative response to the "Surprise Question": a study protocol.

BACKGROUND: The Surprise Question (SQ) "would I be surprised if this patient were to die in the next 12 months?" has been suggested to help clinicians, and especially General Practitioners (GPs), identify people who might benefit from palliative care. The prognostic accuracy of this approach is unclear and little is known about how GPs use this tool in practice. Are GPs consistent, individually and as a group? Are there international differences in the use of the tool? Does including the alternative Surprise Question ("Would I be surprised if the patient were still alive after 12 months?") alter the response? What is the impact on the treatment plan in response to the SQ? This study aims to address these questions. METHODS: An online study will be completed by 600 (100 per country) registered GPs. They will be asked to review 20 hypothetical patient vignettes. For each vignette they will be asked to provide a response to the following four questions: (1) the SQ [Yes/No]; (2) the alternative SQ [Yes/No]; (3) the percentage probability of dying [0% no chance - 100% certain death]; and (4) the proposed treatment plan [multiple choice]. A "surprise threshold" for each participant will be calculated by comparing the responses to the SQ with the probability estimates of death. We will use linear regression to explore any differences in thresholds between countries and other clinician-related factors, such as years of experience. We will describe the actions taken by the clinicians and explore the differences between groups. We will also investigate the relationship between the alternative SQ and the other responses. Participants will receive a certificate of completion and the option to receive feedback on their performance. DISCUSSION: This study explores the extent to which the SQ is consistently used at an individual, group, and national level. The findings of this study will help to understand the clinical value of using the SQ in routine practice. TRIAL REGISTRATION: Clinicaltrials.gov NCT03697213 (05/10/2018). Prospectively registered.

Effects of an extubation readiness test protocol at a tertiary care fully outborn neonatal intensive care unit.

BACKGROUND AND OBJECTIVES: Extubation readiness testing (ERT) in the Neonatal Intensive Care Unit (NICU) is highly variable and lacking standardized criteria. To address this gap, an evidence-based, inter-professionally developed ERT protocol was implemented to assess effectiveness on extubation failure within 72 h and on duration of intubation (DOI). METHODS: A longitudinal retrospective chart review in a level III, fully outborn NICU, of intubated infants admitted 1-year prior (Group 1), and 1 year after implementation (Group 2). Patients were extubated if they passed a 2-stage ERT protocol (3 min continuous positive airway pressure (CPAP) followed by 7 min CPAP + pressure support). Descriptive, comparative statistics, and univariate and multiple logistic regression were completed on all patients and a ≤32 6/7 weeks subgroup (intubated at day-of-life 1); p < 0.05 is considered significant. RESULTS: All patients (n = 589 (n = 294 Group 1, n = 295 Group 2)) were included (preterm, intubated day of life one subgroup: n = 42 Group 1, n = 38 Group 2). For all patients, extubation failure decreased significantly from 9.9% to 4.1% (p = 0.006); Group 1 patients were 2.42 times more likely to experience extubation failure compared with Group 2. Extubation failure in the preterm subgroup decreased from 21.7% to 2.6% (p = 0.01); Group 1 patients were 10.71 times more likely to experience extubation failure. Median DOI was similar in both groups for all patients and in the preterm subgroup. CONCLUSIONS: A unique two-stage ERT protocol was effective at reducing extubation failure rate, without increasing DOI, largely in preterm infants. The evidence-based, interprofessionally developed ERT protocol and its integration into the NICU culture largely contributed to its success.