The effect of automated oxygen control on clinical outcomes in preterm infants: a pre- and post-implementation cohort study

Several studies demonstrated an increase in time spent within target range when automated oxygen control (AOC) is used. However the effect on clinical outcome remains unclear. We compared clinical outcomes of preterm infants born before and after implementation of AOC as standard of care. In a retrospective pre-post implementation cohort study of outcomes for infants of 24-29 weeks gestational age receiving respiratory support before (2012-2015) and after (2015-2018) implementation of AOC as standard of care were compared. Outcomes of interest were mortality and complications of prematurity, number of ventilation days, and length of stay in the Neonatal Intensive Care Unit (NICU). A total of 588 infants were included (293 pre- vs 295 in the post-implementation cohort), with similar gestational age (27.8 weeks pre- vs 27.6 weeks post-implementation), birth weight (1033 grams vs 1035 grams) and other baseline characteristics. Mortality and rate of prematurity complications were not different between the groups. Length of stay in NICU was not different, but duration of invasive ventilation was shorter in infants who received AOC (6.4 +/- 10.1 vs 4.7 +/- 8.3, p = 0.029). Conclusion: In this pre-post comparison, the implementation of AOC did not lead to a change in mortality or morbidity during admission.What is Known:Prolonged and intermittent oxygen saturation deviations are associated with mortality and prematurity-related morbidities.Automated oxygen controllers can increase the time spent within oxygen saturation target range.What is New:Implementation of automated oxygen control as standard of care did not lead to a change in mortality or morbidity during admission.In the period after implementation of automated oxygen control, there was a shift toward more non-invasive ventilation.Developmen

Comparison of two devices for automated oxygen control in preterm infants: a randomised crossover trial

Objective To compare the effect of two different automated oxygen control devices on target range (TR) time and occurrence of hypoxaemic and hyperoxaemic episodes.Design Randomised cross-over study.Setting Tertiary level neonatal unit in the Netherlands.Patients Preterm infants (n=15) born between 24+0 and 29+6 days of gestation, receiving invasive or non-invasive respiratory support with oxygen saturation (SpO(2)) TR of 91%-95%. Median gestational age 26 weeks and 4 days (IQR 25 weeks 3days-27 weeks 6 days) and postnatal age 19 (IQR 17-24) days.Interventions Inspired oxygen concentration was titrated by the OxyGenie controller (SLE6000 ventilator) and the CLIO2 controller (AVEA ventilator) for 24 hours each, in a random sequence, with the respiratory support mode kept constant.Main outcome measures Time spent within set SpO(2) TR (91%-95% with supplemental oxygen and 91%-100% without supplemental oxygen).Results Time spent within the SpO(2) TR was higher during OxyGenie control (80.2 (72.6-82.4)% vs 68.5 (56.7-79.3)%, p<0.005). Less time was spent above TR while in supplemental oxygen (6.3 (5.1-9.9)% vs 15.9 (11.5-30.7)%, p<0.005) but more time spent below TR during OxyGenie control (14.7 (11.8%-17.2%) vs 9.3 (8.2-12.6)%, p<0.05). There was no significant difference in time with SpO(2) <80% (0.5 (0.1-1.0)% vs 0.2 (0.1-0.4)%, p=0.061). Long-lasting SpO(2) deviations occurred less frequently during OxyGenie control.Conclusions The OxyGenie control algorithm was more effective in keeping the oxygen saturation within TR and preventing hyperoxaemia and equally effective in preventing hypoxaemia (SpO(2) <80%), although at the cost of a small increase in mild hypoxaemia.Developmen

S-Phosphocysteine and Phosphohistidine Are Intermediates in the Phosphoenolpyruvate-Dependent Mannitol Transport Catalyzed by Escherichia coli EIIMtl

During a cycle of mannitol transport and phosphorylation, the phosphoryl group originating on P-enolpyruvate is transferred, consecutively, to two sites on the Escherichia coli mannitol-specific carrier (EIIMtl) before being placed on mannitol. The peptides constituting the two EIIMtl phosphorylation sites have been isolated and identified after labeling with [32P]-P-enolpyruvate. The first site is localized in peptide Leu 541-Lys 560. The hydrolysis characteristics of the phosphorylated peptide indicate that a histidine residue is phosphorylated. The second site is located in peptide Ile 380-Met 393, which contains the activity-linked cysteine (384). The hydrolysis characteristics of the phosphopeptide indicate that Cys 384 is the site of phosphorylation

Enzyme IIMtl of the Escherichia coli Phosphoenolpyruvate-Dependent Phosphotransferase System: Identification of the Activity-Linked Cysteine on the Mannitol Carrier

The cysteines of the membrane-bound mannitol-specific enzyme II (EIIMtl) of the Escherichia coli phosphoenolpyruvate-dependent phosphotransferase system have been labeled with 4-vinylpyridine. After proteolytic breakdown and reversed-phase HPLC, the peptides containing cysteines 110, 384, and 571 could be identified. N-Ethylmaleimide (NEM) treatment of the native unphosphorylated enzyme results in incorporation of one NEM label per molecule and loss of enzymatic activity. NEM treatment and inactivation prevented 4-vinylpyridine incorporation into the Cys-384-containing peptide, identifying this residue as the activity-linked cysteine. Both oxidation and phosphorylation of the native enzyme protected the enzyme against NEM labeling of Cys-384. Positive identification of the activity-linked cysteine was accomplished by inactivation with [14C]iodoacetamide, proteolytic fragmentation, isolation of the peptide, and amino acid sequencing.

Bacterial Phosphoenolpyruvate-Dependent Phosphotransferase System: Association State of Membrane-Bound Mannitol-Specific Enzyme II Demonstrated by Radiation Inactivation

The quaternary structure of the membrane-bound mannitol permease (EIIMtl) of the bacterial phosphotransferase system in Escherichia coli has been investigated in the membrane by using the radiation inactivation method. The experiments reveal two distinct but interconvertible forms of the permease. The first state is a dimer, and the second state consists of a less active higher molecular weight complex involving the dimer. The equilibrium between these two forms in the membrane can be shifted by changing the pH. At pH 8.1 the dimer is the dominant form. Decreasing the pH results in increased binding of a regulatory protein to the dimer, thus increasing the amount of the higher molecular weight form involving the dimer. Cross-linking EIIMtl in situ, followed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting, resulted in the formation of two cross-linked forms. One is the dimer, and the other has a higher molecular weight. Two-dimensional electrophoresis using a reversible cross-linker revealed no other protein except EIIMtl in these complexes.

Bacterial Phosphoenolpyruvate-Dependent Phosphotransferase System: Mannitol-Specific EII Contains Two Phosphoryl Binding Sites per Monomer and One High-Affinity Mannitol Binding Site per Dimer

The amino acid composition and sequence of EIIMtl is known. This information was combined, in the present study, with quantitative amino acid analysis to determine the molar concentration of the enzyme. The stoichiometry of phosphoryl group incorporation was then determined by phosphorylation of enzyme II from [14C]phosphoenolpyruvate (pyruvate burst procedure). The native, reduced enzyme incorporated two phosphoryl groups per monomer. Both phosphoryl groups were shown to be transferred to mannitol. Oxidation or N-ethylmaleimide (NEM) labeling of Cys-384 resulted in incorporation of only one phosphoryl group per monomer, which was unable to be transferred to mannitol. The number of mannitol binding sites on enzyme II was determined by centrifugation using Amicon Centricon microconcentrators. The reduced unphosphorylated enzyme contained one high-affinity binding site (KD = 0.1 µM) per dimer and a second site with a KD in the micromolar range. Oxidation or NEM labeling did not change the number of binding sites.

The redox state and the phosphorylation state of the mannitol-specific carrier of the E. coli phosphoenolpyruvate-dependent phosphotransferase system

This review summarizes the recent developments in identifying the activity-linked cysteine as one of the phosphorylation sites on the mannitol-specific EII of the E. coli phosphoenolpyruvate-dependent mannitol transport system. Two phosphorylation sites have been identified, one being the HPr/P-HPr exchange site, the other being the mannitol/mannitol-P exchange site. The activity-linked cysteine and the second phosphorylation site are located in the same 14 residue peptide. Phosphorylation of the second site and phosphoryl group transfer to mannitol do not occur as long as the activity-linked cysteine is oxidized or alkylated. A kinetic scheme has been developed which accounts for the relationships between the redox state, the phosphorylation state and the activity of the carrier. Kinetics of the individual reactions determine whether the enzyme cycles through an oxidized/reduced state during a cycle of phosphorylation/dephosphorylation

Emissiereductie door verneveling van probiotica over leefoppervlak : literatuurstudie en metingen bij vleesvarkens

In twee identieke afdelingen met vleesvarkens is het effect gemeten van het aanbrengen van probiotica (PIP) via het vernevelen er van in de afdeling. Uit de gemeten waarden blijkt er geen significant effect te zijn van het toepassen van probiotica op de emissies van ammoniak (NH3), geur en fijnstof (PM10) en de concentratie van ammoniak