Neurodevelopmental outcomes of preterm infants after randomisation to initial resuscitation with lower (FiO2 <0.3) or higher (FiO2 >0.6) initial oxygen levels. An individual patient meta-analysis

OBJECTIVE

To determine the effects of lower (≤0.3) versus higher (≥0.6) initial fractional inspired oxygen (FiO₂) for resuscitation on death and/or neurodevelopmental impairment (NDI) in infants <32 weeks' gestation.

DESIGN

Meta-analysis of individual patient data from three randomised controlled trials.

SETTING

Neonatal intensive care units.

PATIENTS

543 children <32 weeks' gestation.

INTERVENTION

Randomisation at birth to resuscitation with lower (≤0.3) or higher (≥0.6) initial FiO₂.

OUTCOME MEASURES

Primary: death and/or NDI at 2 years of age.Secondary: post-hoc non-randomised observational analysis of death/NDI according to 5-minute oxygen saturation (SpO₂) below or at/above 80%.

RESULTS

By 2 years of age, 46 of 543 (10%) children had died. Of the 497 survivors, 84 (17%) were lost to follow-up. Bayley Scale of Infant Development (third edition) assessments were conducted on 377 children. Initial FiO₂ was not associated with difference in death and/or disability (difference (95% CI) -0.2%, -7% to 7%, p=0.96) or with cognitive scores <85 (2%, -5% to 9%, p=0.5). Five-minute SpO₂ >80% was associated with decreased disability/death (14%, 7% to 21%) and cognitive scores >85 (10%, 3% to 18%, p=0.01). Multinomial regression analysis noted decreased death with 5-minute SpO₂ ≥80% (odds (95% CI) 09.62, 0.98 to 0.96) and gestation (0.52, 0.41 to 0.65), relative to children without death or NDI.

CONCLUSION

Initial FiO₂ was not associated with difference in risk of disability/death at 2 years in infants <32 weeks' gestation but CIs were wide. Substantial benefit or harm cannot be excluded. Larger randomised studies accounting for patient differences, for example, gestation and gender are urgently needed.

Outcomes of delivery room resuscitation of bradycardic preterm infants: A retrospective cohort study of randomised trials of high vs low initial oxygen concentration and an individual patient data analysis

OBJECTIVE

To determine whether hospital mortality (primary outcome) is associated with duration of bradycardia without chest compressions during delivery room (DR) resuscitation in a retrospective cohort study of randomized controlled trials (RCTs) in preterm infants assigned low versus high initial oxygen concentration.

METHODS

Medline and EMBASE were searched from 01/01/1990 to 12/01/2020. RCTs of low vs high initial oxygen concentration which recorded serial heart rate (HR) and oxygen saturation (SpO2) during resuscitation of infants <32 weeks gestational age were eligible. Individual patient level data were requested from the authors. Newborns receiving chest compressions in the DR and those with no recorded HR in the first 2 min after birth were excluded. Prolonged bradycardia (PB) was defined as HR < 100 bpm for ≥2 min. Individual patient data analysis and pooled data analysis were conducted.

RESULTS

Data were collected from 720 infants in 8 RCTs. Neonates with PB had higher odds of hospital death before [OR 3.8 (95% CI 1.5, 9.3)] and after [OR 1.7 (1.2, 2.5)] adjusting for potential confounders. Bradycardia occurred in 58% infants, while 38% had PB. Infants with bradycardia were more premature and had lower birth weights. The incidence of bradycardia in infants resuscitated with low (≤30%) and high (≥60%) oxygen was similar. Neonates with both, PB and SpO2 < 80% at 5 min after birth had higher odds of hospital mortality. [OR 18.6 (4.3, 79.7)].

CONCLUSION

In preterm infants who did not receive chest compressions in the DR, prolonged bradycardia is associated with hospital mortality.

[Multisystem inflammatory syndrome associated with COVID-19: Not just a pediatric disease]

BACKGROUND

Since the start of the COVID-19 pandemic, a hyperinflammatory syndrome has appeared which develops weeks after a SARS-CoV-2 infection. This multisystem inflammatory syndrome has been described mainly in children (MIS-C), but lately has also been found in adults (MIS-A).

CASE DESCRIPTION

We present a case of a woman with MIS-A. She had fever, diarrhoea, hypotension, laboratory abnormalities with high inflammatory markers, coagulation parameters, troponin-T, N-terminal pro-brain natriuretic peptide (NT-proBNP). Her electrocardiogram had marked diffuse ST-depressions. She was diagnosed in an early stage of MIS-A and treated successfully with immune suppression, antiaggregants and anticoagulants.

CONCLUSION

MIS-A and MIS-C are similar, potentially life-threatening inflammatory syndromes which can lead to severe cardiac dysfunction and cardiovascular failure. For effective treatment and prevention of complications, timely recognition is essential. Clinicians should therefore be mindful of this multisystem inflammatory syndrome, not just in children but also in adults.

Outcomes of oxygen saturation targeting during delivery room stabilisation of preterm infants

OBJECTIVE

To determine the association between SpO₂ at 5 min and preterm infant outcomes.

DESIGN

Data from 768 infants <32 weeks gestation from 8 randomised controlled trials (RCTs) of lower (≤0.3) versus higher (≥0.6) initial inspiratory fractions of oxygen (FiO₂) for resuscitation, were examined.

SETTING

Individual patient analysis of 8 RCTs INTERVENTIONS: Lower (≤0.3) versus higher (≥0.6) oxygen resuscitation strategies targeted to specific predefined SpO₂ before 10 min of age.

PATIENTS

Infants <32 weeks gestation.

MAIN OUTCOME MEASURES

Relationship between SpO₂ at 5 min, death and intraventricular haemorrhage (IVH) >grade 3.

RESULTS

5 min SpO₂ data were obtained from 706 (92%) infants. Only 159 (23%) infants met SpO₂ study targets and 323 (46%) did not reach SpO₂80%. Pooled data showed decreased likelihood of reaching SpO₂80% if resuscitation was initiated with FiO₂ <0.3 (OR 2.63, 95% CI 1.21 to 5.74, p<0.05). SpO₂ <80% was associated with lower heart rates (mean difference -8.37, 95% CI -15.73 to -1.01, *p<0.05) and after accounting for confounders, with IVH (OR 2.04, 95% CI 1.01 to 4.11, p<0.05). Bradycardia (heart rate <100 bpm) at 5 min increased risk of death (OR 4.57, 95% CI 1.62 to 13.98, p<0.05). Taking into account confounders including gestation, birth weight and 5 min bradycardia, risk of death was significantly increased with time taken to reach SpO₂80%.

CONCLUSION

Not reaching SpO₂80% at 5 min is associated with adverse outcomes, including IVH. Whether this is because of infant illness or the amount of oxygen that is administered during stabilisation is uncertain and needs to be examined in randomised trials.

Higher or lower oxygen for delivery room resuscitation of preterm infants below 28 completed weeks gestation: a meta-analysis

OBJECTIVE

To systematically review outcomes of infants ≤28+6 weeks gestation randomised to resuscitation with low (≤0.3) vs high (≥0.6) fraction of inspired oxygen (FiO₂) at delivery.

DESIGN

Systematic review of randomised controlled trials of low (≤0.3) vs high (≥0.6) FiO₂ resuscitation. Information was obtained from databases (Medline/Pub Med, EMBASE, ClinicalTrials.gov, Cochrane) and meeting abstracts between 1990 to 2015. Search index terms: preterm/ resuscitation/oxygen. Data for infants ≤28+6 weeks gestation were independently extracted and pooled using a random effects model. Analyses were performed with Revman V.5.

MAIN OUTCOME MEASURES

Death in hospital, bronchopulmonary dysplasia (BPD), retinopathy of prematurity >grade 2 (ROP), intraventricular haemorrhage >grade 2 (IVH), patent ductus arteriosus (PDA) and necrotising enterocolitis (NEC).

RESULTS

A total of 251 and 253 infants were enrolled in 8 studies (6 masked, 2 unmasked) in the lower and higher oxygen groups, respectively, (mean gestation 26 weeks) between 2005 and 2014. There were no differences in BPD (relative risk, 95% CIs 0.88 (0.68 to 1.14)), IVH (0.81 (0.52 to 1.27)), ROP (0.82 (0.46 to 1.46)), PDA (0.95 (0.80 to 1.14)) and NEC (1.61 (0.67 to 3.36)) and overall mortality (0.99 (0.52 to 1.91)). Mortality was lower in low oxygen arms of masked studies (0.46 (0.23 to 0.92), p=0.03) and higher in low oxygen arms of unmasked studies (1.94 (1.02 to 3.68), p=0.04).

CONCLUSIONS

There is no difference in the overall risk of death or other common preterm morbidities after resuscitation is initiated at delivery with lower (≤0.30) or higher (≥0.6) FiO₂ in infants ≤28+6 weeks gestation. The opposing results for masked and unmasked trials may represent a Type I error, emphasising the need for larger, well designed studies.

Survival and Neurodevelopmental Outcomes of Preterms Resuscitated With Different Oxygen Fractions

BACKGROUND AND OBJECTIVES

Stabilization of preterm infants after birth frequently requires oxygen supplementation. At present the optimal initial oxygen inspiratory fraction (Fio₂) for preterm stabilization after birth is still under debate. We aimed to compare neurodevelopmental outcomes of extremely preterm infants at 24 months corrected age randomly assigned to be stabilized after birth with an initial Fio₂ of 0.3 versus 0.6 to 0.65 in 3 academic centers from Spain and the Netherlands.

METHODS

Randomized, controlled, double-blinded, multicenter, international clinical trial enrolling preterm infants <32 weeks' gestation assigned to an initial Fio₂ of 0.3 (Lowox group) or 0.6 to 0.65 (Hiox group). During stabilization, arterial pulse oxygen saturation and heart rate were continuously monitored and Fio₂ was individually titrated to keep infants within recommended ranges. At 24 months, blinded researchers used the Bayley Scales of Infant and Toddler Development, Third Edition (Bayley-III) to assess visual acuity, neurosensory deafness, and language skills.

RESULTS

A total of 253 infants were recruited and 206 (81.4%) completed follow-up. No differences in perinatal characteristics, oxidative stress, or morbidities during the neonatal period were assessed. Mortality at hospital discharge or when follow-up was completed didn't show differences between the groups. No differences regarding Bayley-III scale scores (motor, cognitive, and language composites), neurosensorial handicaps, cerebral palsy, or language skills between groups were found.

CONCLUSIONS

The use of an initial lower (0.3) or higher (0.6-0.65) Fio₂ during stabilization of extremely preterm infants in the delivery room does not influence survival or neurodevelopmental outcomes at 24 months.

Urinary Lipid Peroxidation Byproducts: Are They Relevant for Predicting Neonatal Morbidity in Preterm Infants?

Preterm infants have an immature antioxidant system; however, they frequently require supplemental oxygen. Oxygen-free radicals cause both pulmonary and systemic inflammation, and they are associated with increased morbidity and mortality. Consequently, screening of metabolite profiles representing the amount of lipid peroxidation is considered of great relevance for the evaluation of in vivo oxidative stress and derived inflammation and damage. Ranges for total relative contents of isoprostanes (IsoPs), isofurans (IsoFs), neuroprostanes (NeuroPs), and neurofurans (NeuroFs) within targeted SpO2 ranges were determined in urine samples of 254 preterm infants<32 weeks of gestation within the frame of two randomized, controlled, and blinded clinical trials employing ultra-performance liquid chromatography-tandem mass spectrometry. A total of 536 serial urine samples collected during the first 4 weeks after birth in recruited infants who did not develop free radical associated conditions were analyzed. A reference range for lipid peroxidation byproducts, including isoprostanes, isofurans, neuroprostanes, and neurofurans, was calculated and possible correlations with neonatal conditions were investigated. Urinary elimination of isofurans in the first 4 days after birth correlated with later development of bronchopulmonary dysplasia. Our observations lead to the hypothesis that early urinary determination of lipid peroxidation byproducts, especially isofurans, is relevant to predict development of chronic lung conditions.

Albumin synthesis in very low birth weight infants is enhanced by early parenteral lipid and high-dose amino acid administration

BACKGROUND & AIMS

Albumin is one of the most important plasma proteins and plays a key role in many physiologic processes, such as preserving colloid osmotic pressure, scavenging radicals, and binding and transporting bilirubin, hormones, and drugs. However, albumin concentrations are often low in preterm infants during the first days of life. We hypothesized that early parenteral lipid and high-dose amino acid (AA) administration to very low birth weight (VLBW) infants from birth onwards increases hepatic albumin synthesis rates.

METHODS

Inborn VLBW infants were randomized to receive from birth onwards either 2.4 g amino acids/(kg(·)d) (control group), 2.4 g amino acids/(kg(·)d) plus 2 g lipids/(kg(·)d) (AA + lipid group), or 3.6 g amino acids/(kg(·)d) plus 2 g lipids/(kg(·)d) (high AA + lipid group). On postnatal day 2, infants received a primed continuous infusion of [U-(13)C6,(15)N]leucine. Mass spectrometry was used to determine the fractional and absolute albumin synthesis rates (FSR and ASR, respectively).

RESULTS

In total, 28 infants (median gestational age 27 weeks (IQR 25-28), median birth weight 810 g (IQR 679-998) were studied. The median FSR was 6.5%/d in the control group, 10.6%/d in the AA group, and 12.3%/d in the high AA + lipid group, while the median was 84 mg/(kg(·)d) in the control group, 138 mg/(kg(·)d) in the AA group, and 160 mg/(kg(·)d) in the high AA + lipid group.

CONCLUSION

A group of VLBW infants given parenteral nutrition containing lipids and high-dose amino acids showed a higher rate of albumin synthesis compared to infants receiving no lipids and standard amounts of amino acids during the first two days of life.

Resuscitation of preterm infants with different inspired oxygen fractions

OBJECTIVE

To test the hypothesis that an initial fraction of inspired oxygen (FiO2) of 30% during resuscitation of preterm infants results in less oxidative stress and is associated with improved clinical outcomes compared with an FiO2 of 65%.

STUDY DESIGN

Preterm infants of gestational age <32 weeks (n = 193) were randomized to start resuscitation with either 30% oxygen (low-oxygen group) or 65% oxygen (high-oxygen group), after which the FiO2 was adjusted based on oxygen saturation values. The primary outcome was bronchopulmonary dysplasia (BPD) assessed at 36 weeks postmenstrual age. Secondary outcomes included major neonatal illnesses and markers of oxidative stress.

RESULTS

The median gestational age of included infants was 28(6)/7 weeks (IQR, 26(5)/7-30(3)/7 weeks). The incidence of BPD was not significantly different between the low-oxygen and high-oxygen groups (24% vs. 17%; P = .15). The FiO2 in both groups was adjusted to a mean of 40% by 7 minutes in the low-oxygen group and by 11 minutes in the high-oxygen group. No differences in markers of oxidative stress were noted between groups.

CONCLUSION

Initial supplementation of preterm infants with 30% oxygen during the fetal-to-neonatal transition is as safe as 65% oxygen, with no differences in oxidative stress markers or BPD.

Analysis of lipid peroxidation biomarkers in extremely low gestational age neonate urines by UPLC-MS/MS

Extremely low gestational age neonates (ELGAN) frequently require the use of oxygen supply in the delivery room leading to systemic inflammation and oxidative stress that are responsible for increased morbidity and mortality. The objective of this study was to establish reference ranges of a set of representative isoprostanes and prostaglandins, which are stable biomarkers of lipid peroxidation often correlated with oxidative stress-related disorders. First, a quantitative ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method was developed and validated. The proposed analytical method was tailored for its application in the field of neonatology, enabling multi-analyte detection in non-invasive, small-volume urine samples. Then, the lipid peroxidation product concentrations in a total of 536 urine samples collected within the framework of two clinical trials including extremely low gestational age neonates (ELGAN) were analyzed. The access to a substantially large number of samples from this very vulnerable population provided the chance to establish reference ranges of the studied biomarkers. Up to the present, and for this population, this is the biggest reference data set reported in literature. Results obtained should assist researchers and pediatricians in interpreting test results in future studies involving isoprostanes and prostaglandins, and could help assessing morbidities and evaluate effectiveness of treatment strategies (e.g., different resuscitation conditions) in the neonatal field.

Assessment of oxidative damage to proteins and DNA in urine of newborn infants by a validated UPLC-MS/MS approach

The assessment of oxidative stress is highly relevant in clinical Perinatology as it is associated to adverse outcomes in newborn infants. This study summarizes results from the validation of an Ultra Performance Liquid Chromatography–tandem Mass Spectrometry (UPLC-MS/MS) method for the simultaneous quantification of the urinary concentrations of a set of endogenous biomarkers, capable to provide a valid snapshot of the oxidative stress status applicable in human clinical trials, especially in the field of Perinatology. The set of analytes included are phenylalanine (Phe), para-tyrosine (p-Tyr), ortho-tyrosine (o-Tyr), meta-tyrosine (m-Tyr), 3-NO₂-tyrosine (3NO₂-Tyr), 3-Cl-tyrosine (3Cl-Tyr), 2′-deoxyguanosine (2dG) and 8-hydroxy-2′-deoxyguanosine (8OHdG). Following the FDA-based guidelines, appropriate levels of accuracy and precision, as well as adequate levels of sensitivity with limits of detection (LODs) in the low nanomolar (nmol/L) range were confirmed after method validation. The validity of the proposed UPLC-MS/MS method was assessed by analysing urine samples from a clinical trial in extremely low birth weight (ELBW) infants randomized to be resuscitated with two different initial inspiratory fractions of oxygen.

Adaptive regulation of amino acid metabolism on early parenteral lipid and high-dose amino acid administration in VLBW infants - a randomized, controlled trial

BACKGROUND & AIMS

An anabolic state can be achieved upon intravenous amino acid administration during the immediate postnatal phase despite a low energy intake. The optimal dosing of amino acid and energy intake has yet to be established. The aim was to quantify the efficacy of early initiation of parenteral lipids and increased amounts of amino acids on metabolism and protein accretion in very low birth weight infants.

METHODS

28 very low birth weight infants were randomized to receive parenteral nutrition with glucose and either 2.4 g amino acids/(kg·d) (control group), 2.4 g amino acids/(kg·d) plus 2-3 g lipid/(kg·d) (AA + lipid group), or 3.6 g amino acids/(kg·d) plus 2-3 g lipid/(kg·d) (high AA + lipid group) from birth onward. On postnatal day 2, we performed a stable isotope study with [1-(13)C]phenylalanine, [ring-D4]tyrosine, [U-(13)C6,(15)N]leucine, and [methyl-D3]α-ketoisocaproic acid to quantify intermediate amino acid metabolism.

RESULTS

The addition of lipids only had no effect on phenylalanine metabolism, whereas the addition of both lipids and additional amino acids increased the amount of phenylalanine used for protein synthesis. In addition, high amino acid intake significantly increased the rate of hydroxylation of phenylalanine to tyrosine, increasing the availability of tyrosine for protein synthesis. However, it also increased urea concentrations. Increasing energy intake from 40 to 60 kcal/(kg·d) did not increase protein efficiency as measured by phenylalanine kinetics. The leucine data were difficult to interpret due to the wide range of results and inconsistency in the data between the phenylalanine and leucine models.

CONCLUSIONS

High amino acid and energy intakes from birth onwards result in a more anabolic state in very low birth weight infants, but at the expense of higher urea concentrations, which reflects a higher amino acid oxidation. Long-term outcome data should reveal whether this policy deserves routine implementation. This trial was registered at www.trialregister.nl, trial number NTR1445, name Nutritional Intervention for Preterm Infants-2.

Safety and efficacy of early parenteral lipid and high-dose amino acid administration to very low birth weight infants

OBJECTIVE

To assess the efficacy and safety of early parenteral lipid and high-dose amino acid (AA) administration from birth onwards in very low birth weight (VLBW, birth weight <1500 g) infants.

STUDY DESIGN

VLBW infants (n = 144; birth weight 862 ± 218 g; gestational age 27.4 ± 2.2 weeks) were randomized to receive 2.4 g of AA kg(-1) · d(-1) (control group), or 2.4 g AA kg(-1) · d(-1) plus 2-3 g lipids kg(-1) · d(-1) (AA + lipid group), or 3.6 g AA kg(-1) · d(-1) plus 2-3 g lipids kg(-1) · d(-1) (high AA + lipid group) from birth onwards. The primary outcome was nitrogen balance. The secondary outcomes were biochemical variables, urea rate of appearance, growth rates, and clinical outcome.

RESULTS

The nitrogen balance on day 2 was significantly greater in both intervention groups compared with the control group. Greater amounts of AA administration did not further improve nitrogen balance compared with standard AA dose plus lipids and was associated with high plasma urea concentrations and high rates of urea appearance. No differences in other biochemical variables, growth, or clinical outcomes were observed.

CONCLUSIONS

In VLBW infants, the administration of parenteral AA combined with lipids from birth onwards improved conditions for anabolism and growth, as shown by improved nitrogen balance. Greater levels of AA administration did not further improve the nitrogen balance but led to increased AA oxidation. Early lipid initiation and high-dose AA were well tolerated.

Increased CD4(+) T cell co-inhibitory immune receptor CEACAM1 in neonatal sepsis and soluble-CEACAM1 in meningococcal sepsis: a role in sepsis-associated immune suppression?

The co-inhibitory immune receptor carcinoembryonic antigen-related cell-adhesion molecule 1 (CEACAM1) and its self-ligand CEACAM1 can suppress T cell function. Suppression of T cell function in sepsis is well documented. Late-onset neonatal sepsis in VLBW-infants was associated with an increased percentage CEACAM1 positive CD4⁺ T-cells. Meningococcal septic shock in children was associated with increased serum soluble CEACAM1. In conclusion our data demonstrate increased surface expression of the co-inhibitory immune receptor CEACAM1 in late-onset neonatal sepsis in VLBW-infants, and increased circulating soluble CEACAM1 in children with meningococcal sepsis. Increased T-cell CEACAM1 expression and increased circulating soluble CEACAM1 may contribute to sepsis-associated immune suppression.

Observing the resuscitation of very preterm infants: are we able to follow the oxygen saturation targets?

BACKGROUND

Since 2010, the European Resuscitation Council (ERC) guidelines advise oxygen saturation (SpO2) targets for the first 10 min of resuscitation after birth. Unfortunately, the control of SpO2 in newborn infants is difficult.

AIM

To determine to what extent SpO2 levels match the ERC targets during the resuscitation of very preterm infants, and how well the SpO2 is kept within the high and low limits until the infants are transported to the NICU.

METHODS

In a single-centre observational study, the SpO2 and fraction of inspired oxygen (FiO2) were collected during the resuscitation of very preterm infants with a gestational age (GA)≤ 30 weeks.

RESULTS

A total of 78 infants were included [median (IQR): GA 27(4)/7 (26-28(6)/7) weeks, birth weight 945 g (780-1140)]. During the initial 10 min after birth, large variations in SpO2 were observed with deviations above the target [median (IQR)] of 4.4% SpO2 (1.4-6.5), and below the target of 8.2% SpO2 (2.8-16.0). After the first 10 min, the SpO2 levels were respectively above and below the limit for 11% (0-27) and 8% (0-23) of the time.

CONCLUSION

During the resuscitation of very preterm infants, large deviations of the SpO2 from the ERC targets are observed. During the first minutes of resuscitation the deviations were likely caused by an inability to control the SpO2, whereas later deviations were due to weaning, pauses in respiratory support (i.e. intubation) and over exposure to oxygen. Changing the SpO2 targets to a target range that depicts the acceptable deviation might be helpful in providing better respiratory support.

Resuscitation of very preterm infants with 30% vs. 65% oxygen at birth: study protocol for a randomized controlled trial

Background

Resuscitation at birth with 100% oxygen is known to increase the oxidative burden with concomitant deleterious effects. Although fractions of inspired oxygen (FiO₂) < 100% are widely used in preterm infants, starting resuscitation at a (too) low FiO₂ may result in hypoxia. The objective of this study is to compare the safety and efficacy of resuscitating very preterm infants with an initial FiO₂ of 30% versus 65%.

Methods/design

In this double-blind, randomized controlled trial, 200 very preterm infants with a gestational age < 32 weeks will be randomized to start resuscitation after birth with either 30% or 65% oxygen. The FiO₂ will be adjusted based on oxygen saturation measured by pulse oximetry (SpO₂) and pulse rate (which should be over 100 beats per minute) in order to achieve a target SpO₂ of 88–94% at 10 min of life. The FiO₂ and pulse oximetry data will be continuously recorded.

The primary outcome is survival without bronchopulmonary dysplasia, as assessed by a physiological test at 36 weeks postmenstrual age. The secondary outcomes include the time to achieve SpO₂ > 88%, Apgar score at 5 min, cumulative O₂ exposure, oxidative stress (as determined by glutathione synthesis and oxidative stress markers), retinopathy of prematurity, brain injury and neurodevelopmental outcome at 2 years of age.

This study will provide insight into determining the appropriate initial FiO₂ to start resuscitation of very preterm infants.

Trial registration

http://www.trialregister.nl, NTR243.

Glutathione synthesis rates in early postnatal life

Preterm infants have diminished antioxidant defenses. Glutathione (GSH), the main intracellular antioxidant, increases upon amino acid (AA) administration in preterm infants, without an accompanying rise of the fractional synthesis rate of GSH (FSRGSH) This study investigated the mechanism behind this increased GSH concentration by determining GSH synthesis in the first days after birth using stable isotope techniques in very low-birth-weight (VLBW) infants receiving i.v. AAs. Advanced oxidized protein products (AOPPs) were determined to quantify oxidative stress. Eighteen infants (birth weight 989 +/- 241 g, gestational age of 27/7 +/- 1/7 weeks) were studied either on postnatal day 1 or 2 (7 or 31 h postnatally, respectively). Concentration of GSH increased with postnatal age (1.45 +/- 0.48 mM versus 1.99 +/- 0.40 mM, p = 0.019). FSRGSH was not significantly different, but the absolute synthesis rate of GSH (ASRGSH) tended to be higher in the infants studied on day 2 [8.1 +/- 2.7 mg/(kg . d) versus 10.6 +/- 2.4 mg/(kg . d), p = 0.054]. AOPP concentrations were not different between groups. In conclusion, GSH concentration in VLBW infants increases significantly after birth. A concomitant increased synthesis rate was not found, suggesting that GSH consumption decreases upon AA administration.

Simultaneous analysis of (13)C-glutathione as its dimeric form GSSG and its precursor [1-(13)C]glycine using liquid chromatography/isotope ratio mass spectrometry

Determination of glutathione kinetics using stable isotopes requires accurate measurement of the tracers and tracees. Previously, the precursor and synthesized product were measured with two separate techniques, liquid chromatography/isotope ratio mass spectrometry (LC/IRMS) and gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS). In order to reduce sample volume and minimize analytical effort we developed a method to simultaneously determine (13)C-glutathione as its dimeric form (GSSG) and its precursor [1-(13)C]glycine in a small volume of erythrocytes in one single analysis. After having transformed (13)C-glutathione into its dimeric form GSSG, we determined both the intra-erythrocytic concentrations and the (13)C-isotopic enrichment of GSSG and glycine in 150 microL of whole blood using liquid chromatography coupled to LC/IRMS. The results show that the concentration (range of micromol/mL) was reliably measured using cycloleucine as internal standard, i.e. with a precision better than 0.1 micromol/mL. The (13)C-isotopic enrichment of GSSG and glycine measured in the same run gave reliable values with excellent precision (standard deviation (sd) <0.3 per thousand) and accuracy (measured between 0 and 5 APE). This novel method opens up a variety of kinetic studies with relatively low dose administration of tracers, reducing the total cost of the study design. In addition, only a minimal sample volume is required, enabling studies even in very small subjects, such as preterm infants.

Miscarriage but not fecundity is associated with progression of joint destruction in rheumatoid arthritis

OBJECTIVE

To determine whether reproductive history before disease onset is associated with severity of joint destruction in rheumatoid arthritis.

METHODS

A special early arthritis clinic (EAC) was established at the department of rheumatology of Leiden University Medical Centre. General practitioners were encouraged to refer patients with joint complaints to this clinic, where the diagnosis of rheumatoid arthritis was made by a rheumatologist. In all, 113 female patients with definite rheumatoid arthritis were included in this study. A structured questionnaire was administered and joint damage was assessed by sequential x rays of the hands and feet, using the modified Sharp score.

RESULTS

The length of time of unprotected intercourse until first pregnancy (fecundity) was comparable with data from earlier studies, with 16% of the patients reporting a time to first pregnancy of more than 12 months. Fecundity did not reflect the extent of joint damage over time. The miscarriage rate was 15% per pregnancy, comparable to population figures (12-15%). A significant increase in joint damage over a two year follow up was found in patients with rheumatoid arthritis who had experienced at least one miscarriage compared with those who had never had a miscarriage (mean modified Sharp scores at 2 years, 24 (95% confidence interval, 15 to 32) and 16 (10 to 23), respectively; p<0.05). At baseline, the Sharp scores were similar in the two subgroups.

CONCLUSIONS

Miscarriage before disease onset but not fecundity is associated with the progression of joint damage in rheumatoid arthritis.

Human neutrophil defensins induce lung epithelial cell proliferation in vitro

Repair of injured airway epithelium is often accompanied by an influx of leukocytes, and these cells have been suggested to contribute to the repair process. The aim of the present study was to investigate the effect of neutrophil defensins--antimicrobial peptides present in large amounts in the neutrophil--on proliferation of cultured lung epithelial cells. Neutrophil defensins at 4-10 microg/ml enhanced proliferation of the A549 lung epithelial cell line as assessed using cell counting, BrdU incorporation, and the tetrazolium salt MTT assay. Higher, cytotoxic concentrations of defensins decreased cell proliferation. Whereas defensin-induced cell proliferation was not inhibited by the EGF receptor tyrosine kinase inhibitor AG1478, it was completely inhibited by the mitogen-activated protein (MAP) kinase kinase (MEK) inhibitor U0126, suggesting that defensins mediate cell proliferation via an EGF receptor-independent, MAP kinase signaling pathway. Although the cytotoxic effect of defensins was inhibited by alpha1-proteinase inhibitor, the defensin-induced cell proliferation was not affected. These data suggest that neutrophil defensins may possibly be involved in epithelial repair in the airways by inducing lung epithelial cell proliferation.

Targeting of liver tumour in rats by selective delivery of holmium-166 loaded microspheres: a biodistribution study

Intra-arterial administration of beta-emitting particles that become trapped in the vascular bed of a tumour and remain there while delivering high doses, represents a unique approach in the treatment of both primary and metastatic liver tumours. Studies on selective internal radiation therapy of colorectal liver metastases using yttrium-90 glass microspheres have shown encouraging results. This study describes the biodistribution of 40-microm poly lactic acid microspheres loaded with radioactive holmium-166, after intra-arterial administration into the hepatic artery of rats with implanted liver tumours. Radioactivity measurements showed >95% retention of injected activity in the liver and its resident tumour. The average activity detected in other tissues was < or =0.1%ID/g, with incidental exceptions in the lungs and stomach. Very little 166Ho activity was detected in kidneys (<0.1%ID/g), thereby indicating the stability of the microspheres in vivo. Tumour targeting was very effective, with a mean tumour to liver ratio of 6. 1+/-2.9 for rats with tumour (n=15) versus 0.7+/-0.5 for control rats (n=6; P<0.001). These ratios were not significantly affected by the use of adrenaline. Histological analysis showed that five times as many large (>10) and medium-sized (4-9) clusters of microspheres were present within tumour and peritumoural tissue, compared with normal liver. Single microspheres were equally dispersed throughout the tumour, as well as normal liver parenchyma.