Ruminal methane emission and lactational performance of cows fed rapeseed cake and oats on a grass silage-based diet

The objective of this experiment was to investigate the effect of lipid from rapeseed cake and oats on ruminal CH4 emission and lactational performance of dairy cows. Twelve lactating Nordic Red cows, of which 4 primiparous, and averaging (±SD) 48 ± 22.9 DIM, 37.8 ± 7.14 kg/d milk yield were enrolled in a switch-back design experiment with 3 periods of 4 wk each. The cows were assigned into 6 pairs based on parity and days-in-milk, milk yield, and body weight at the beginning of the experiment. The experimental treatments were 1) rapeseed cake and oats (RSC+O), and 2) rapeseed meal and barley (RSM+B) as the concentrate feeds. Cows in each pair were randomly assigned to one of the 2 groups, which received the treatments in 2 different sequences, i.e., group 1 received RSC+O in period 1 and 3, and RSM+B in period 2, whereas group 2 was fed RSM+B in period 1 and 3, and RSC+O in period 2. The diets consisted of a partially mixed ration with grass silage mixed with either oats or barley, according to the treatment sequence, and the rapeseed cake or meal being mixed into a pellet with either oats or barley according to the treatments, and a mineral mix. The pellet was delivered at a fixed amount (i.e., 6 kg/d for multiparous and 5 kg/d for the primiparous cows) from the milking robot. The actual forage to concentrate ratios for RSC+O and RSM+B were 51:49 and 52:48, respectively, with NDF concentrations of 41.5 and 36.0% and CP concentrations of 17.0 and 16.7% of diet DM. Dry matter intake, milk yield, and gas exchange (with a GreenFeed system attached to the milking robot) were recorded daily, and milk composition and spot fecal samples were collected during the last wk of each period. Based on feed analysis, and dry matter intake of the cows during the experiment, the total fat content of the experimental diets was 4.1 and 2.7% of DM for RSC+O and RSM+B diets, respectively. Dry matter intake was 1.5 kg/d lower, and milk yield tended to be 1.0 kg/d greater for RSC+O vs. RSM+B. There were no differences in energy-corrected milk yield and milk composition between the treatments, while milk metabolizable energy efficiency was greater for cows fed RSC+O than RSM+B. Methane yield (g/kg dry matter intake) did not differ between treatments, but CH4 production (g/d) was 9.4% and CH4 intensity as g/kg energy-corrected milk was 11.7% lower for RSC+O vs. RSM+B. The lower CH4 production was likely caused by the lower DMI and fiber digestibility, observed with the RSC+O diet. In addition, the greater lipid intake also contributed to lower rate of fermentation and subsequent decrease in CH4 production. Overall, feeding rapeseed cake with oats in a grass silage-based diet increased feed efficiency while decreasing CH4 emission intensity in lactating cows. This provides a practical way of mitigating ruminal CH4 emission from dairy operations while maintaining milk production with commonly utilized feed stuffs in Nordic conditions.

Adult congenital heart disease training in Europe: current status, disparities and potential solutions

OBJECTIVES

This study aimed to determine the status of training of adult congenital heart disease (ACHD) cardiologists in Europe.

METHODS

A questionnaire was sent to ACHD cardiologists from 34 European countries.

RESULTS

Representatives from 31 of 34 countries (91%) responded. ACHD cardiology was recognised by the respective ministry of Health in two countries (7%) as a subspecialty. Two countries (7%) have formally recognised ACHD training programmes, 15 (48%) have informal (neither accredited nor certified) training and 14 (45%) have very limited or no programme. Twenty-five countries (81%) described training ACHD doctors 'on the job'. The median number of ACHD centres per country was 4 (range 0-28), median number of ACHD surgical centres was 3 (0-26) and the median number of ACHD training centres was 2 (range 0-28). An established exit examination in ACHD was conducted in only one country (3%) and formal certification provided by two countries (7%). ACHD cardiologist number versus gross domestic product Pearson correlation coefficient=0.789 (p<0.001).

CONCLUSION

Formal or accredited training in ACHD is rare among European countries. Many countries have very limited or no training and resort to 'train people on the job'. Few countries provide either an exit examination or certification. Efforts to harmonise training and establish standards in exit examination and certification may improve training and consequently promote the alignment of high-quality patient care.

An ultra-sensitive NH3 gas sensor enabled by an ion-in-conjugated polycroconaine/Ti3C2Tx core-shell composite

MXenes are emerging sensing materials due to their metallic conductivity and rich surface chemistry for analytes; they, however, suffer from poor stability. Incorporation with functional polymers can largely prevent the performance decay and enhance the sensing performance. Herein, we demonstrate a core-shell composite, Ti₃C₂T_x@croconaine (poly(1,5-diaminonaphthalene-croconaine), PDAC) prepared by a facile in situ polymerization reaction, suitable for NH₃ detection. Compared to pristine Ti₃C₂T_x, the sensor made of a Ti₃C₂T_x-polycroconaine composite exhibits a significantly enhanced sensitivity of 2.8% ppm^-1 and an estimated achievable limit of detection of 50 ppb. The improved sensing performance could be attributed to the presence of PDAC facilitating the adsorption of NH₃ and changing the tunneling conductivity between Ti₃C₂T_x domains. Density functional theory (DFT) calculations reveal that the adsorption energy of NH₃ on PDAC is the highest among the tested gases, which supports the selectivity of the sensor to this analyte. Benefiting from the protection conferred by the PDAC shell, the composite has a reliable operation period of at least 40 days. In addition, we demonstrated a flexible paper-based sensor of the Ti₃C₂T_x@PDAC composite, without attenuated performance upon mechanical deformation. This work proposed a novel mechanism and a feasible methodology to synthesize MXene-polymer composites with improved sensitivity and stability for chemical sensing.

Processed fava bean as a substitute for rapeseed meal with or without rumen-protected methionine supplement in grass silage-based dairy cow diets

Fava bean offers a sustainable home-grown protein source for dairy cows, but fava bean protein is extensively degraded in the rumen and has low Met concentration. We studied the effects of protein supplementation and source on milk production, rumen fermentation, N use, and mammary AA utilization. The treatments were unsupplemented control diet, and isonitrogenously given rapeseed meal (RSM), processed (dehulled, flaked, and heated) fava bean without (TFB) or with rumen-protected (RP) Met (TFB+). All diets consisted of 50% grass silage and 50% cereal-based concentrate including studied protein supplement. The control diet had 15% of crude protein and protein-supplemented diets 18%. Rumen-protected Met in TFB+ corresponded to 15 g/d of Met absorbed in the small intestine. Experimental design was a replicated 4 × 4 Latin square with 3-wk periods. The experiment was conducted using 12 multiparous mid-lactation Nordic Red cows, of which 4 were rumen cannulated. Protein supplementation increased dry matter intake (DMI), and milk (31.9 vs. 30.7 kg/d) and milk component yields. Substituting RSM with TFB or TFB+ decreased DMI and AA intake but increased starch intake. There were no differences in milk yield or composition between RSM diet and TFB diets. Rumen-protected Met did not affect DMI, or milk or milk component yields but increased milk protein concentration in comparison to TFB. There were no differences in rumen fermentation except for increased ammonium-N concentration with the protein-supplemented diets. Nitrogen-use efficiency for milk production was lower for the supplemented diets versus control diet but tended to be greater for TFB and TFB+ versus RSM. Protein supplementation increased plasma essential AA concentration but there were no differences between TFB diets and RSM. Rumen-protected Met clearly increased plasma Met concentration (30.8 vs. 18.2 µmol/L) but did not affect other AA. Absence of differences between RSM and TFB in milk production together with limited effects of RP Met suggest that TFB is a potential alternative protein source for dairy cattle.

Biopolymer Blends of Poly(lactic acid) and Poly(hydroxybutyrate) and Their Functionalization with Glycerol Triacetate and Chitin Nanocrystals for Food Packaging Applications

Polylactic acid (PLA) is a biopolymer that has potential for use in food packaging applications; however, its low crystallinity and poor gas barrier properties limit its use. This study aimed to increase the understanding of the structure property relation of biopolymer blends and their nanocomposites. The crystallinity of the final materials and their effect on barrier properties was studied. Two strategies were performed: first, different concentrations of poly(hydroxybutyrate) (PHB; 10, 25, and 50 wt %) were compounded with PLA to facilitate the PHB spherulite development, and then, for further increase of the overall crystallinity, glycerol triacetate (GTA) functionalized chitin nanocrystals (ChNCs) were added. The PLA:PHB blend with 25 wt % PHB showed the formation of many very small PHB spherulites with the highest PHB crystallinity among the examined compositions and was selected as the matrix for the ChNC nanocomposites. Then, ChNCs with different concentrations (0.5, 1, and 2 wt %) were added to the 75:25 PLA:PHB blend using the liquid-assisted extrusion process in the presence of GTA. The addition of the ChNCs resulted in an improvement in the crystallization rate and degree of PHB crystallinity as well as mechanical properties. The nanocomposite with the highest crystallinity resulted in greatly decreased oxygen (O) and carbon dioxide (CO₂) permeability and increased the overall mechanical properties compared to the blend with GTA. This study shows that the addition ChNCs in PLA:PHB can be a possible way to reach suitable gas barrier properties for food packaging films.

Ultrafast photoresponse of vertically oriented TMD films probed in a vertical electrode configuration on Si chips

Integrated photodetectors based on transition metal dichalcogenides (TMDs) face the challenge of growing their high-quality crystals directly on chips or transferring them to the desired locations of components by applying multi-step processes. Herein, we show that vertically oriented polycrystalline thin films of MoS₂ and WS₂ grown by sulfurization of Mo and W sputtered on highly doped Si are robust solutions to achieve on-chip photodetectors with a sensitivity of up to 1 mA W^-1 and an ultrafast response time in the sub-μs regime by simply probing the device in a vertical arrangement, i.e., parallel to the basal planes of TMDs. These results are two orders of magnitude better than those measured earlier in lateral probing setups having both electrodes on top of vertically aligned polycrystalline TMD films. Accordingly, our study suggests that easy-to-grow vertically oriented polycrystalline thin film structures may be viable components in fast photodetectors as well as in imaging, sensing and telecommunication devices.

Bioplastics and Carbon-Based Sustainable Materials, Components, and Devices: Toward Green Electronics

The continuously growing number of short-life electronics equipment inherently results in a massive amount of problematic waste, which poses risks of environmental pollution, endangers human health, and causes socioeconomic problems. Hence, to mitigate these negative impacts, it is our common interest to substitute conventional materials (polymers and metals) used in electronics devices with their environmentally benign renewable counterparts, wherever possible, while considering the aspects of functionality, manufacturability, and cost. To support such an effort, in this study, we explore the use of biodegradable bioplastics, such as polylactic acid (PLA), its blends with polyhydroxybutyrate (PHB) and composites with pyrolyzed lignin (PL), and multiwalled carbon nanotubes (MWCNTs), in conjunction with processes typical in the fabrication of electronics components, including plasma treatment, dip coating, inkjet and screen printing, as well as hot mixing, extrusion, and molding. We show that after a short argon plasma treatment of the surface of hot-blown PLA-PHB blend films, percolating networks of single-walled carbon nanotubes (SWCNTs) having sheet resistance well below 1 kΩ/□ can be deposited by dip coating to make electrode plates of capacitive touch sensors. We also demonstrate that the bioplastic films, as flexible dielectric substrates, are suitable for depositing conductive micropatterns of SWCNTs and Ag (1 kΩ/□ and 1 Ω/□, respectively) by means of inkjet and screen printing, with potential in printed circuit board applications. In addition, we exemplify compounded and molded composites of PLA with PL and MWCNTs as excellent candidates for electromagnetic interference shielding materials in the K-band radio frequencies (18.0-26.5 GHz) with shielding effectiveness of up to 40 and 46 dB, respectively.

Inkjet-Deposited Single-Wall Carbon Nanotube Micropatterns on Stretchable PDMS-Ag Substrate-Electrode Structures for Piezoresistive Strain Sensing

Printed piezoresistive strain sensors based on stretchable roll-to-roll screen-printed silver electrodes on polydimethylsiloxane substrates and inkjet-deposited single-wall carbon nanotube micropatterns are demonstrated in this work. With the optimization of surface wetting and inkjet printing parameters, well-defined microscopic line patterns of the nanotubes with a sheet resistance of <100 Ω/□ could be deposited between stretchable Ag electrodes on the plasma-treated substrate. The developed stretchable devices are highly sensitive to tensile strain with a gauge factor of up to 400 and a pressure sensitivity of ∼0.09 Pa^-1, respond to bending down to a radius of 1.5 mm, and are suitable for mounting on the skin to monitor and resolve various movements of the human body such as cardiac cycle, breathing, and finger flexing. This study indicates that inkjet deposition of nanomaterials can complement well other printing technologies to produce flexible and stretchable devices in a versatile manner.

Composites of ion-in-conjugation polysquaraine and SWCNTs for the detection of H2S and NH3 at ppb concentrations

Several different methods are established for the analysis of gases, including optical spectroscopy, photoacoustic spectroscopy as well as colorimetric and resistive sensing, the measurements systems are either too complex or have limited sensitivity. In particular, when the goal is to apply a large number of sensors in networks, it is highly desirable to have devices that are simple, have low cost and energy consumption, yet sensitive and selective to monitor analytes even in traces. Herein, we propose a new type of resistive sensor device based on a composite of single-wall carbon nanotubes and an ion-in-conjugation polymer, poly(1,5-diaminonaphthalene-squaraine), capable of detecting H2S and NH3 in air even at room temperature with a theoretical concentration limit of ∼1 ppb and ∼7 ppb, respectively. Density functional theory calculations revealed that H atoms of the analytes and O atoms of the polymer chain interact and form hydrogen bonds, and the electron withdrawal from the gas molecules by the polymer chain results in the change of its electrical conductivity. To demonstrate the feasibility of the new nanocomposites in sensing, we show the devices for monitoring food safety with good sensor stability of operation for at least 3 months of period of time.

Flexible planar supercapacitors by straightforward filtration and laser processing steps

There is ever increasing demand for flexible energy storage devices due to the development of wearable electronics and other small electronic devices. The electrode flexibility is best provided by a special set of nanomaterials, but the required methodology typically consists of multiple steps and are designed just for the specific materials. Here, a facile and scalable method of making flexible and mechanically robust planar supercapacitors with interdigital electrode structure made of commercial carbon nanomaterials and silver nanowires is presented. The capacitor structure is achieved with vacuum filtration through a micropatterned contact mask and finished with simple laser processing steps. A maximum specific capacitance of 4 F cm^-3 was measured with cyclic voltammetry at scan rate of 5 mV s^-1. The reliability and charge transfer properties of devices were further investigated with galvanostatic charge-discharge measurements and electrochemical impedance spectroscopy, respectively. Furthermore, mechanical bending tests confirmed the devices have excellent mechanical integrity, and the deformations have no adverse effects on the electrochemical charge-discharge behavior and stability.

Ultra-low permittivity porous silica-cellulose nanocomposite substrates for 6G telecommunication

The continuously increasing demand for faster data traffic of our telecommunication devices requires new and better materials and devices that operate at higher frequencies than today. In this work, a porous composite of silica nanoshells and cellulose nanofibers is demonstrated as a suitable candidate of dielectric substrates to be used in future 6G frequency bands. The hollow nanospheres of amorphous SiO₂ with outstanding electromagnetic properties were obtained by a template-assisted Stöber process, in which a thin shell of silica is grown on polystyrene nanospheres first, and then the polymer core is burned off in a subsequent step. To be able to produce substrates with sufficient mechanical integrity, the nanoshells of SiO2 were reinforced with cellulose nanofibers resulting in a porous composite of very low mass density (0.19 ± 0.02 g cm^-3), which is easy to press and mold to form films or slabs. The low relative dielectric permittivity (ε _r = 1.19 ± 0.01 at 300 GHz and ε _r = 1.17 ± 0.01 at 2.0 THz) and corresponding loss tangent (tan δ= 0.011 ± 0.001 at 300 GHz and tan δ = 0.011 ± 0.001 at 2.0 THz) of the composite films are exploited in substrates for radio frequency filter structures designed for 300 GHz operation.

Stretchable Sensors with Tunability and Single Stimuli-Responsiveness through Resistivity Switching Under Compressive Stress

The fascinating human somatosensory system with its complex structure is composed of numerous sensory receptors possessing distinct responsiveness to stimuli. It is a continuous source of inspiration for tactile sensors that mimic its functions. However, to achieve single stimulus-responsiveness with mechanical decoupling is particularly challenging in the light of structural design and has not been fully addressed to date. Here we propose a novel structural design inspired by combining the characteristics of electronic skin (e-skin) and electronic textile (e-textile) into a hybrid interface to achieve a stretchable single stimuli-responsive tactile sensor. The stencil printable biocarbon composite/silver-plated nylon hybrid interface possesses an extraordinary resistance switching (ΔR/R0 up to ∼104) under compressive stress which is controllable by the composite film-thickness. It achieves a very high normal pressure sensitivity (up to 60.8 kPa-1) in a wide dynamic range (up to ∼50 kPa) in the piezoresistive operation mode and can effectively decouple stresses induced by stretching or bending. In addition, the device is capable of high accuracy strain sensing in its capacitive operation mode through dimensional change dominant response. Because of these intriguing features, it has potential for the next-generation Internet of Things devices and user-interactive systems capable of providing visual feedback and more advanced robotics or even prosthetics.

Lightweight Hierarchical Carbon Nanocomposites with Highly Efficient and Tunable Electromagnetic Interference Shielding Properties

High-performance electromagnetic interference shielding is becoming vital for the next generation of telecommunication and sensor devices among which portable and wearable applications require highly flexible and lightweight materials having efficient absorption-dominant shielding. Herein, we report on lightweight carbon foam-carbon nanotube/carbon nanofiber nanocomposites that are synthesized in a two-step robust process including a simple carbonization of open-pore structure melamine foams and subsequent growth of carbon nanotubes/nanofibers by chemical vapor deposition. The microstructure of the nanocomposites resembles a 3-dimensional hierarchical network of carbonaceous skeleton surrounded with a tangled web of bamboo-shaped carbon nanotubes and layered graphitic carbon nanofibers. The microstructure of the porous composite enables absorption-dominant (absorbance ∼0.9) electromagnetic interference shielding with an effectiveness of ∼20-30 dB and with an equivalent mass density normalized shielding effectiveness of ∼800-1700 dB cm³ g^-1 at the K-band frequency (18-26.5 GHz). Moreover, the hydrophobic nature of the materials grants water-repellency and stability in humid conditions important for reliable operation in outdoor use, whereas the mechanical flexibility and durability with excellent piezoresistive behavior enable strain-responsive tuning of electrical conductivity and electromagnetic interference shielding, adding on further functionalities. The demonstrated nanocomposites are versatile and will contribute to the development of reliable devices not only in telecommunication but also in wearable electronics, aerospace engineering, and robotics among others.

Size-Dependent H₂ Sensing Over Supported Pt Nanoparticles

Catalyst size affects the overall kinetics and mechanism of almost all heterogeneous chemical reactions. Since the functional sensing materials in resistive chemical sensors are practically the very same nanomaterials as the catalysts in heterogeneous chemistry, a plausible question arises: Is there any effect of the catalyst size on the sensor properties? Our study attempts to give an insight into the problem by analyzing the response and sensitivity of resistive H₂ sensors based on WO₃ nanowire supported Pt nanoparticles having size of 1.5±0.4 nm, 6.2±0.8 nm, 3.7±0.5 nm and 8.3±1.3 nm. The results show that Pt nanoparticles of larger size are more active in H₂ sensing than their smaller counterparts and indicate that the detection mechanism is more complex than just considering the number of surface atoms of the catalyst.

Heterozygous junctophilin-2 (JPH2) p.(Thr161Lys) is a monogenic cause for HCM with heart failure

During the last two decades, mutations in sarcomere genes have found to comprise the most common cause for hypertrophic cardiomyopathy (HCM), but still significant number of patients with dominant HCM in the family are left without molecular genetic diagnosis. Next generation sequencing (NGS) does not only enable evaluation of established HCM genes but also candidate genes for cardiomyopathy are frequently tested which may lead to a situation where conclusive interpretation of the variant requires extensive family studies. We aimed to characterize the phenotype related to a variant in the junctophilin-2 (JPH2) gene, which is less known non-sarcomeric candidate gene. In addition, we did extensive review of the literature and databases about JPH2 variation in association with cardiac disease. We characterize nine Finnish index patients with HCM and heterozygous for JPH2 c.482C>A, p.(Thr161Lys) variant were included and segregation studies were performed. We identified 20 individuals affected with HCM with or without systolic heart failure and conduction abnormalities in the nine Finnish families with JPH2 p.(Thr161Lys) variant. We found 26 heterozygotes with the variant and penetrance was 71% by age 60 and 100% by age 80. Co-segregation of the variant with HCM phenotype was observed in six families. Main clinical features were left ventricular hypertrophy, arrhythmia vulnerability and conduction abnormalities including third degree AV-block. In some patients end-stage severe left ventricular heart failure with normal or mildly enlarged diastolic dimensions was detected. In conclusion, we propose that the heterozygous JPH2 p.(Thr161Lys) variant is a new Finnish mutation causing atypical HCM.

The effect of two different doses of remifentanil on postoperative pain and opioid consumption after cardiac surgery--a randomized controlled trial

BACKGROUND

Remifentanil, an ultra-short-acting opioid, provides intensive analgesia without prolonged respiratory depression and is widely used in cardiac surgery. Diminished dosing may also offer stable hemodynamics, even during sternotomy and sternal retraction. However, increased postoperative pain and induced opioid tolerance after remifentanil dosing during abdominal surgery was reported. We tested whether remifentanil 0.3 μg/kg/min infusion increased postoperative opioid consumption and pain compared to 0.1 μg/kg/min dosing.

METHODS

Ninety coronary artery bypass grafting or heart valve surgery patients were randomized to remifentanil 0.1 μg/kg/min or 0.3 μg/kg/min infusions during surgery. All patients received oxycodone bolus 0.15 μg/kg postoperatively, and patient-controlled analgesia (PCA) with oxycodone thereafter. Postoperative pain was estimated thrice daily by visual analogue scale, and 48-h opioid consumption was recorded from the PCA-device.

RESULTS

Total remifentanil dosing was 64 μg/kg in the higher and 22 μg/kg in the lower dosing group during the 3-h cardiac operations. Mean postoperative opioid consumption was 107 (SD 36) mg in the lower and 104 (SD 33) mg in the higher dose remifentanil groups. Postoperative pain did not differ between groups, at rest or during deep breathing, at any time (P = 0.110 and 0.941, respectively).

CONCLUSIONS

Remifentanil 0.3 μg/kg/min infusion did not increase postoperative pain or opioid consumption after cardiac surgery compared to the 0.1 μg/kg/min infusion. Remifentanil infusion 0.1-0.3 μg/kg/min during cardiac surgery was safe, with no exaggerated postoperative pain or opioid consumption.

Carbon supported catalysts in low temperature steam reforming of ethanol: study of catalyst performance

The difference in performance and deactivation of carbon supported catalysts in low temperature SRE are studied and explained.

Lung Ultrasound and Static Lung Compliance during Postnatal Adaptation in Healthy Term Infants

BACKGROUND

B-lines in lung ultrasound can be used to estimate lung liquid. B-lines are ring-down artifacts that arise from alterations to subpleural lung parenchyma. Lung ultrasound has been used to differentiate between diseases causing respiratory symptoms in neonates. B-lines are also seen in healthy infants during postnatal adaptation. Static lung compliance is a measure of the elasticity of the lungs.

OBJECTIVES

Our aim was to document lung ultrasound findings, static lung compliance and their relationship during postnatal adaptation in healthy term infants.

METHODS

Lung ultrasound and measurement of static lung compliance were performed in 34 infants at ages of 0-4 and 24 h. B-lines in lung ultrasound were scored using a 5-step scale. Separate ultrasound scores for the upper and lower fields were also calculated.

RESULTS

A significant decrease in the abundance of B-lines and a concomitant significant improvement in static lung compliance was observed from <4 to 24 h of age. At <4 h the B-lines were significantly more abundant in the lower fields. No significant correlation existed between lung ultrasound and static lung compliance.

CONCLUSION

The concomitant decrease in the B-lines in ultrasound and the increase in lung compliance during the first 24 h are likely to reflect clearance of lung liquid.

Industrially benign super-compressible piezoresistive carbon foams with predefined wetting properties: from environmental to electrical applications

In the present work electrically conductive, flexible, lightweight carbon sponge materials derived from open-pore structure melamine foams are studied and explored. Hydrophobic and hydrophilic surface properties - depending on the chosen treatment conditions - allow the separation and storage of liquid chemical compounds. Activation of the carbonaceous structures substantially increases the specific surface area from ~4 m²g⁻¹ to ~345 m²g⁻¹, while retaining the original three-dimensional, open-pore structure suitable for hosting, for example, Ni catalyst nanoparticles. In turn the structure is rendered suitable for hydrogenating acetone to 2-propanol and methyl isobutyl ketone as well for growing hierarchical carbon nanotube structures used as electric double-layer capacitor electrodes with specific capacitance of ~40 F/g. Mechanical stress-strain analysis indicates the materials are super-compressible (>70% volume reduction) and viscoelastic with excellent damping behavior (loss of 0.69 ± 0.07), while piezoresistive measurements show very high gauge factors (from ~20 to 50) over a large range of deformations. The cost-effective, robust and scalable synthesis - in conjunction with their fascinating multifunctional utility - makes the demonstrated carbon foams remarkable competitors with other three-dimensional carbon materials typically based on pyrolyzed biopolymers or on covalently bonded graphene and carbon nanotube frameworks.

[Fetal arrhythmias]

The majority of referrals for fetal arrhythmias represent benign atrial premature beats. However, a small number of fetuses might have life-threatening conditions associated with bradycardia or tachycardia. Fetal echocardiography is essential to establish the diagnosis. Transplacental treatment is most often used to prevent heart failure. There is no clinical trial evidence as to the drug of first choice. Prognosis is determined by the type of arrhythmia, the association with structural cardiac anomaly and the co-existence of intrauterine cardiac failure. Treatment of fetal dysrhythmias should be executed in experienced maternal-fetal medicine centers.

[Prenatal screening and diagnosis of severe congenital heart defects in Finland]

INTRODUCTION

Careful investigation of the heart for finding structural heart defects is an essential part of nationwide fetal anomaly screening at 20th weeks of gestation which took effect in 2010.

PATIENTS AND METHODS

We studied the results of fetal cardiac screening in infants having a major congenital cardiac defect in 2005-2011.

RESULTS

28% of severe cardiac defects were detected prenatally. Univentricular heart defects were prenatally found in 87% of all cases. Screening for transposition of great arteries and conotruncal defects remains challenging.

CONCLUSIONS

More active approach with a rapid referral is recommended for abnormal cardiac findings in fetal structural screening.

Delayed lung liquid absorption after cesarean section at term

BACKGROUND

Delayed postnatal removal of lung liquid may result in respiratory distress, which is more common in infants born by cesarean section. Vertical artefacts (B-lines) arising from the lung surface in lung ultrasound have been shown to correlate with the liquid content of the lungs.

OBJECTIVES

We studied whether lung ultrasound could be used for the assessment of postnatal lung liquid in healthy term infants born vaginally and by cesarean section.

METHODS

Lung ultrasound was performed 1, 3 and 24 h after birth to 22 vaginally born infants and 20 infants born by elective cesarean section. The abundance of B-lines was scored for each infant and time point by two independent observers blinded to the mode of delivery and time point on the examination on a five-step scale.

RESULTS

In both groups, a significant decrease in abundance of B-lines, indicative of lung liquid absorption, was observed during the first 24 h. 3 h after birth cesarean section was associated with significantly higher lung liquid content than vaginal delivery.

CONCLUSION

The noninvasive bedside ultrasound method for estimation of lung liquid is a promising tool for the early identification of infants at risk for pulmonary maladaptation.

Impact of coronary artery bypass surgery on ischemic mitral regurgitation

INTRODUCTION

To determine the course of ischemic mitral regurgitation (IMR) after coronary artery bypass grafting (CABG), and evaluate preoperative factors which predict the development of the severity of IMR after CABG.

METHODS

Between 1992-2005, 1995 patients underwent CABG and 170 of them had IMR. Data of 131 patients were retrospectively analyzed and living patients (n = 112) had a clinical follow-up visit. The mean follow-up time was 6.5 years.

RESULTS

At the time of CABG, 66% of the 131 cases analyzed had mild, 31% had moderate, and 3% had severe IMR. At the time of follow-up, 52% of patients had either no IMR or mild IMR, 27% had moderate IMR, 6% had severe IMR and 15% suffered from cardiac related death. During follow-up IMR grade reduced in 25% of study patients. None of the patient had re-operation due to the mitral regurgitation. Multivariate analysis showed that left ventricular ejection fraction (LVEF) was an independent predictor of good prognosis (O.R. 1.4, 95% C.I. 1.15-1.83/ 10% increase of LVEF, p = 0.02).

CONCLUSION

Half of the patients, who have IMR at the time of CABG, have no IMR or only mild IMR postoperatively. Good LVEF adds to the probability that CABG only can reduce IMR.

Mobile-centric ambient intelligence in health- and homecare-anticipating ethical and legal challenges

Ambient Intelligence provides the potential for vast and varied applications, bringing with it both promise and peril. The development of Ambient Intelligence applications poses a number of ethical and legal concerns. Mobile devices are increasingly evolving into tools to orientate in and interact with the environment, thus introducing a user-centric approach to Ambient Intelligence. The MINAmI (Micro-Nano integrated platform for transverse Ambient Intelligence applications) FP6 research project aims at creating core technologies for mobile device based Ambient Intelligence services. In this paper we assess five scenarios that demonstrate forthcoming MINAmI-based applications focusing on healthcare, assistive technology, homecare, and everyday life in general. A legal and ethical analysis of the scenarios is conducted, which reveals various conflicting interests. The paper concludes with some thoughts on drafting ethical guidelines for Ambient Intelligence applications.

Liquid phase deposition of polymers on arbitrary shaped surfaces and their suitability for e-beam patterning

We present a straightforward low cost liquid phase deposition method to coat arbitrary-shaped dielectric substrates with uniform electron beam sensitive polymer films. Furthermore, we investigate the use of electron beam lithography to pattern the coated pre-form substrates. The polymers studied are poly-methyl-methacrylate with different molecular weights, poly(methyl methacrylate-co-ethyl acrylate) and methyl methacrylate. The polymer coverage over the whole surface area is shown to be uniform and the thickness of the film dependent on the concentration of the polymer liquid used. As the uniform polymer layer is deposited on non-flat surfaces, we show that with an electron beam various surfaces, e.g. microlens arrays, can be re-patterned accurately with nanoscale features. Furthermore, we show the required dose for electron beam exposure to be dependent on the concentration and on the molecular weight of the polymer used.

Pulmonary fluid balance in the human newborn infant

At birth, the infant's lungs must be cleared of fetal lung fluid. This process is mediated through the activation of airway epithelial sodium channels (ENaC). In animals, ENaC is considered crucial for postnatal pulmonary adaptation. In humans, postnatal ENaC expression is gestational age dependent and its activity, measured as nasal potential difference, correlates with lung compliance. It is therefore likely that in the human newborn infant ENaC is also important for physiologic postnatal adaptation. Low pulmonary expression or activity of ENaC in the perinatal period may cause delayed clearance of lung fluid and thereby contribute to development of respiratory distress in both term and preterm infants.

Myocardial function in patients with Shwachman-Diamond syndrome: aspects to consider before stem cell transplantation

BACKGROUND

Early studies have suggested increased risk of fatal cardiac complications in infants with Shwachman-Diamond syndrome (SDS), an inherited bone marrow failure syndrome. Patients undergoing stem cell transplantation (STC) have appeared susceptible to organ toxicity, including cardiac involvement.

PROCEDURE

This study assessed anatomical and functional features of the heart in SDS. Eight patients (mean age 24.1 years, range 7-37 years, seven males) with SDS and confirmed SBDS mutations were prospectively assessed for cardiac anatomy, myocardial wall properties, and systolic and diastolic function. The study protocol included conventional echocardiography (n = 8) complemented by exercise Tissue-Doppler echocardiography (n = 7), and by MRI (n = 6).

RESULTS

No abnormalities in cardiac anatomy or function were observed in baseline clinical assessment, EKG, or conventional echocardiographic and MRI measurements. Myocardial structure and left ventricular (LV) mass were normal. The maximum isovolumic acceleration (IVA) value during exercise in Tissue-Doppler was significantly lower (P < 0.001), and the right ventricular (RV) ejection fraction (P = 0.02) and peak filling rate (PFR, P = 0.008) at rest in MRI were higher in patients.

CONCLUSIONS

Children and young adults with SDS and mutations in SBDS had normal cardiac anatomy and myocardial structure. Subtle RV diastolic function alterations at rest and depressed LV contractility during exercise were observed. Further studies are warranted to evaluate the clinical importance of these findings.

Expression of the epithelial sodium channel in airway epithelium of newborn infants depends on gestational age

OBJECTIVE

In the newborn infant, removal of fetal lung liquid from the airways depends on ion transport through the airway epithelium. The epithelial sodium channel is considered rate limiting for the postnatal clearance of lung liquid, but it is unknown whether during the early postnatal period the expression of epithelial sodium channel is associated with maturity. Our objective was to study the relationship between gestational age and epithelial sodium channel expression in airway epithelium.

METHODS

In 90 newborn infants (preterm [gestational age < 37]: n = 29; term [gestational age > or = 37]: n = 61), we measured the expression of epithelial sodium channel (reported as attomoles of subunit expression normalized to femtomoles of expression of cytokeratin 18) in nasal epithelium at 1 to 5 and 22 to 28 hours after birth.

RESULTS

At 1 to 5 hours postnatally, airway expression of alpha-, beta-, and gamma-subunits of epithelial sodium channel was lower in preterm than in term infants. At this time point, significant correlations existed between gestational age and airway expression of alpha- and beta-epithelial sodium channel. By 22 to 28 hours after birth, only the expression of beta-epithelial sodium channel had decreased significantly in the preterm infants, whereas the expression of all epithelial sodium channel subunits had decreased significantly in the term infants. At this time point, no difference in expression of any of the subunits was found between preterm and term infants.

CONCLUSIONS

Airway expression of epithelial sodium channel at 1 to 5 hours of age is significantly lower in preterm than in term infants. Low postnatal expression of alpha-, beta-, and gamma-epithelial sodium channel subunits in the airway epithelium may contribute to the development of respiratory distress in the preterm infant.

Auditory-evoked potentials in bispectral index-guided anaesthesia for cardiac surgery

BACKGROUND AND OBJECTIVE

Midlatency auditory-evoked potentials, as measures of the anaesthetic state, were evaluated at similar levels of bispectral index in cardiac surgical patients maintained with either propofol or isoflurane anaesthesia.

METHODS

Twenty-four patients were randomly allocated to anaesthesia with propofol (n = 12) or isoflurane (n = 12). Bispectral index was maintained below 60 during surgery. Auditory-evoked potentials were collected before induction of anaesthesia, 10 min after intubation, 30 min after sternotomy, during cardiopulmonary bypass at the time of cross-clamping of the aorta and during stable mild hypothermia, after de-clamping of the aorta, and after the operation.

RESULTS

At the pre-determined time points, bispectral index values showed comparable depth of hypnosis in both groups. The latency of the Nb component of midlatency auditory-evoked potentials was significantly increased in the isoflurane group after intubation (P < 0.001) and that of both the Nb and the Pa components after sternotomy (P < 0.001) compared with the propofol group. No differences between the groups were detected with respect to haemodynamic variables. No patient reported recall of intraoperative events.

CONCLUSION

After intubation and surgical stimulation, when bispectral index was at a constant level, there was a difference in the Nb and Pa components of the midlatency auditory-evoked potentials between the two anaesthetic regimens, indicating a distinction in the state of anaesthesia. Our results suggest that the parallel use of these two electrophysiological methods can show differences in the components of anaesthesia between various anaesthesia methods in cardiac surgical patients.

Infants with univentricular heart have reduced heart rate and blood pressure responses to side motion and altered responses to head-up tilt

Cardiovascular control was studied in infants with univentricular heart (UVH). Side motion tests and 45-s 45° head-up tilt tests were performed in 11 control and 9 UVH infants at the age of 13 ± 3.2 wk. In addition, heart rate (HR) reactions to spontaneous arousals and HR variability during slow-wave sleep (SWS) were determined. All UVH infants had been hypoxic for several weeks, and during the sleep study the mean arterial oxyhemoglobin saturation was 82 ± 5%. Tests were done at night during SWS, confirmed by polysomnographic recording. Continuous beat-to-beat blood pressure (BP) was measured. In the side-motion tests, control infants consistently showed a transient increase in HR and BP. This response was markedly reduced in all of the UVH infants ( P < 0.0001). In tilt tests, the UVH infants showed normal BP responses, but, although a sustained 2.0% decrease in HR was observed in the controls, the UVH infants presented with a sustained 2.6% mean HR increase ( P = 0.005). The UVH infants also showed attenuated HR acceleration during spontaneous arousals ( P = 0.01), but HR variability did not differ significantly from the controls. In conclusion, UVH infants with chronic hypoxia exhibit defective vestibulosympathetic pathways, as expressed by an absence of acute HR and BP reactivity to side motion. HR reactions to postural challenge and spontaneous arousal are also altered. Autonomic function abnormalities in these infants are suggested to be secondary to hypoxia.

Sodium transport in airway epithelium correlates with lung compliance in healthy newborn infants

To study the relation between sodium transport in airway epithelium and postnatal pulmonary adaptation, we measured nasal potential difference at 1 to 4 hours and lung compliance at 21 to 48 hours after birth in 20 healthy infants. Sodium transport correlated with lung compliance ( r 2 = 0.40, P < .003). Airway sodium transport plays a role in postnatal pulmonary adaptation.

Lung Epithelial Ion Transport in Neonatal Lung Disease

Lung epithelial ion transport promotes salt and water movement across the fetal and neonatal lung epithelium. The mechanism is dependent on basolateral membrane Na-K-ATPase and the apical membrane Cl(-) and Na(+) channels. During fetal life active secretion of Cl(-) and parallel movement of Na(+) across the epithelium into the developing lung lumen induce accumulation of liquid into the future airspaces. Postnatally, however, absorption of fluid from the airspaces must start. Present evidence suggests that activation of Na(+) transport from the lumen into the basolateral direction drives fluid absorption and results in an essentially dry air-filled alveolus. In laboratory animals amiloride, a Na(+) channel blocker, induces respiratory distress and impedes lung fluid clearance. One of the epithelial amiloride-sensitive Na(+) channels, ENaC, is composed of three homologous subunits that differentially respond to glucocorticoid hormone. In newborn infants an increase in pulmonary fluid and a defective Na(+) transport associate with respiratory distress. The ontogeny, subunit composition and function of ENaC along the respiratory tract are currently under investigation. It will be interesting to find out whether the subunit composition and function of lung ENaC respond to the therapy of the critically ill newborn infant.

Right atrial isomerism in four siblings

Heterotaxy syndromes, right or left atrial isomerism, result from disruption of left-right axis determination and their manifestations include complicated heart defects. Recent studies in model organisms have revealed complex genetic pathways and several genes involved in this process. In affected humans, however, molecular studies have identified mutations in a small number of individuals, while in most the cause remains unknown. Furthermore, although family data suggest, autosomal recessive inheritance, such genes have not yet been identified. We have studied six members of a family, four children affected with right atrial isomerism (RAI) and their healthy parents, for disturbances of left-right axis development. The children, one female and three males who all had complicated heart defects, succumbed and had an autopsy. Their nonconsanguineous parents were examined by cardiac and abdominal ultrasound or MRI. In all four children the heart defects included single ventricle with dysplastic atrioventricular (AV) valve, total anomalous pulmonary venous drainage (TAPVD), and malposition of great arteries (MGA) with pulmonary stenosis (PS). All had asplenia; two also had dextrocardia and abdominal situs inversus. The diagnosis of RAI was made postnatally in the first child and prenatally in others. Two siblings had no surgery and died as a newborn, one with obstructed supracardiac TAPVD and the other with regurgitating AV valve. Two children underwent heart surgery. One had repair of obstructive infracardiac TAPVD but died in infancy. The other underwent both hemi-Fontan operation and heart transplantation but died at the age of 2 years. This is the first report describing four children with RAI in the same family. The occurrence of RAI in male and female siblings without any indication of left-right axis abnormalities in their parents suggests autosomal recessive inheritance of human isomerism.

Feasibility of predicting the risk of atrial fibrillation after coronary artery bypass surgery with logistic regression model

BACKGROUND AND AIMS

The aim of this study was to determine the risk factors of postoperative atrial fibrillation (AF) after coronary artery bypass grafting and to create predictive model and to evaluate the effects of AF on patients outcome.

MATERIAL AND METHODS

Data of 3,676 consecutive patients were analysed to identify the predictors of AF. Multivariate logistic regression model was validated prospectively in 1,107 patients.

RESULTS

Increasing age (p < 0.001), preoperative use of digoxin (p = 003), need of intra-aortic balloon pump or inotropic medication in the weaning off cardiopulmonary by pass or during the first 24 hours postoperatively (p = 0.013), increasing body surface area (p = 0.006) and lower ejection fraction (p = 0.048) were independent risk factors for postoperative AF. The predictive model gave area under the receiver-operating characteristic (ROC) curve 0.682, 95% confidence interval 0.663-0.701, and p < 0.001. The patients with AF incidence had more postoperative stroke (p = 0.008), confusion (p < 0.001) severe gastrointestinal complications (p = 0.005), readmission to ICU (p < 0.001), longer ICU (p < 0.001) and hospital stay (p < 0.001) when compared with the patients who remained in sinus rhythm.

CONCLUSION

Logistic regression model with the parameters used was not accurate enough for clinical purposes. Postoperative AF is associated with postoperative stroke, severe gastrointestinal complications, readmission to ICU, and longer ICU and hospital stay.

Intra-institutional prediction of outcome after cardiac surgery: comparison between a locally derived model and the EuroSCORE

OBJECTIVE

To construct models for predicting mortality, morbidity and length of intensive care unit (ICU) stay after cardiac surgery and to compare the performance of these models with that of the EuroSCORE in two independent validation databases.

METHODS

Clinical data on 4592 cardiac surgery patients operated between 1992 and 1996 were retrospectively collected. In order to derive predictive models and to validate them, the patient population was randomly divided into a derivation database (n=3061) and a validation database (n=1531). Variables that were significant in univariate analyses were entered into a backward stepwise logistic regression model. The outcome was defined as mortality within 30 days after surgery, predefined morbidity, and the length of ICU stay lasting >2 days. In addition to the retrospective database, the models were validated also in a prospectively collected database of cardiac surgical patients operated in 1998-1999 (n=821). The EuroSCORE was tested in two validation databases, i.e. the retrospective and prospective one. Hosmer-Lemeshow goodness-of-fit was used to study the calibration of the predictive models. Area under the receiver operating characteristic (ROC) curve was used to study the discrimination ability of the models.

RESULTS

The overall mortality in the retrospective and the prospective data was 2 and 1%, and morbidity 22 and 18%, respectively. The created predictive models fitted well in the validation databases. Our models and the EuroSCORE were equally good in discriminating patients. Thus, in the prospective validation database, the mean areas under the ROC curve for our models and for the EuroSCORE were similar, i.e. 0.84 and 0.77 for mortality, 0.74 and 0.74 for morbidity, and 0.81 and 0.79 for the length of intensive care unit stay lasting for 2 days or more, respectively.

CONCLUSIONS

Our models and the EuroSCORE were equally good in discriminating the patients in respect to outcome. However, our model provided also well calibrated estimation of the probability of prolonged ICU stay for each patient. As was originally suggested, the EuroSCORE may be an appropriate tool in categorizing cardiac surgical patients into various subgroups in interinstitutional comparisons. Our models may have additive value especially in resource allocation and quality assurance purposes for local use.

O2-induced ENaC expression is associated with NF-kappaB activation and blocked by superoxide scavenger

Cultured rat fetal distal lung epithelial cells (FDLEs), when switched from fetal (3%) to postnatal (21%) O2 concentrations, have increased epithelial Na+ channel (ENaC) mRNA levels and amiloride-sensitive Na+ transport [O. Pitkänen, A. K. Tanswell, G. Downey, and H. O'Brodovich. Am. J. Physiol. 270 (Lung Cell. Mol. Physiol. 14): L1060-L1066, 1996]. The mechanisms by which O2 mediates these effects are unknown. After isolation, FDLEs were kept at 3% O2 overnight, then switched to 21% O2 (3-21% O2 group) or maintained at 3% O2 (3-3% O2 group) for 48 h. The amiloride-sensitive short-circuit current (Isc) in the 3-21% O2 group was double that in the 3-3% O2 group. Amiloride-sensitive Isc could not be induced by medium conditioned by 21% O2-exposed FDLEs but was reversed by returning the cells to 3% O2. Neither the cyclooxygenase inhibitor ibuprofen, liposome-encapsulated catalase, nor hydroperoxide scavengers (U-74389G or Trolox) blocked the O2-induced amiloride-sensitive Isc. In contrast, the cell-permeable superoxide scavenger tetramethylpiperidine-N-oxyl (TEMPO) eliminated the O2-induced increases in amiloride-sensitive Isc and ENaC mRNA levels. The switch from 3 to 21% O2 induced the transcription factor nuclear factor-kappaB, which could also be blocked by TEMPO. We conclude that 1) the O2-induced increase in amiloride-sensitive Isc is reversible and 2) the O2-induced increase in amiloride-sensitive Isc and ENaC mRNA levels is associated with activation of nuclear factor-kappaB and may be mediated, at least in part, by superoxide.

Hyperamylasemia after cardiopulmonary bypass: pancreatic cellular injury or impaired renal excretion of amylase?

BACKGROUND

Postoperative hyperamylasemia and even acute pancreatitis are associated with coronary artery bypass grafting (CABG). The mechanism of hyperamylasemia and pancreatic acinar cell damage was studied in 20 patients undergoing CABG.

METHODS

Serial blood and urine samples at eight time points before, during, and 24 hours after the CABG were collected. Salivary and pancreatic isoamylases, the fractional clearance of isoamylases (i.e., relative to creatinine clearance), pancreatic phospholipase A2 (a specific serum marker of pancreatic acinar cell injury), and cystatin C (a sensitive marker of glomerular filtration rate) were measured.

RESULTS

Mild serum hyperamylasemia (300 to 1000 units/L) was found in 11 of 20 (55%) and severe (> 1000 units/L) in 6 of 20 (30%) patients with no signs of clinical acute pancreatitis. Hyperamylasemia occurred from 6 to 24 hours after the CABG and was mainly caused by pancreatic isoamylase. Serum pancreatic phospholipase A2 concentration remained unchanged, which excludes acinar cell damage. Although renal glomerular filtration was normal during CABG as measured by serum cystatin C and creatinine clearance, the fractional clearance of isoamylases decreased.

CONCLUSIONS

The decreased rate of excretion into urine, rather than pancreatic cellular damage, is the major source of hyperamylasemia after CABG.

Enzymatic determination of unbound D-mannose in serum

Mannose is an aldohexose component of a number of glycoproteins in cellular membranes and blood plasma. Free (unbound) mannose is a normal blood plasma constituent and its concentration is elevated in diabetes mellitus and chronic glomerulonephritis. We devised an enzymatic method for the determination of free mannose in which mannose is converted to glucose-6-phosphate and measured spectrophotometrically using glucose-6-phosphate dehydrogenase and nicotinamide adenine dinucleotide phosphate (NADP). Accumulation of reduced NADP in the assay was verified by spectral analysis and by finding rapid disappearance of absorbance at 340 nm on addition of glutathione reductase and oxidized glutathione into the reaction mixture. The method necessitates prior removal of glucose from the samples. This we accomplished using glucose-6-phosphate dehydrogenase and a surplus amount of NADP, followed by elimination of reduced NADP by acidification of the reaction mixture. The assays may be run in parallel for expediency. Concentration of free mannose in serum was 18.5 +/- 5.5 mumol/l in healthy fasting female adults. The analytical recovery was 90.2 +/- 10.2% and the between-run imprecision was 13.5% (18.5 +/- 5.5 mumol/l, mean +/- SD) and 10.4% (75.3 +/- 10.3 mumol/l). The assay showed rectilinearity up to 220 mumol/l, which covers the measuring range to which the mannose concentrations in normal and clinical samples may be expected to fall.

Increased Po2 alters the bioelectric properties of fetal distal lung epithelium

At birth the lung must efficiently clear the liquid from its air spaces and permanently convert from a fluid-secreting to a fluid-absorbing organ. When primary cultures of rat fetal distal lung epithelium (FDLE) grown on permeable supports were switched from a fetal (3%) to a postnatal (21%) oxygen environment, there was an increase in epithelial permeability as reflected by a dose-dependent decline in transepithelial resistance (Rt) 4 h later (3% = 239 +/- 19 omega.cm2; 21% = 170 +/- 28 omega.cm2; 50% = 98 +/- 20 omega.cm2; P < 0.05). The effect was transient, since monolayers initially maintained at 3% and switched to these higher oxygen concentrations subsequently had Rt values comparable to the 3% group at 48 h (3% = 153 +/- 17 omega.cm2; 21% = 181 +/- 19 omega.cm2; 50% = 192 +/- 21 omega.cm2; P = NS). Changes in Rt were associated with expected changes in the histological appearance of the interepithelial tight junctions, but intracellular actin content and distribution remained constant. Amiloride-sensitive equivalent short-circuit current increased within 18 h, with further increases after 48 h of exposure to postnatal oxygen concentrations. Ion substitution experiments suggested diminished FDLE Cl transport and increased Na transport. The amount of FDLE-alpha, -beta, and -gamma rat epithelial Na channel mRNA increased within 48 h of increasing the ambient oxygen concentration. These results suggest that the physiological increase in alveolar Po2 at birth is, at least in part, responsible for distal lung's permanent switch from Cl secretion to Na absorption at birth.

Immaturity-dependent free radical activity in premature infants

To examine the role of immaturity in the free radical-mediated rate of lipid peroxidation in premature infants, we studied 27 infants [gestational age, 27.1 (SD 2.4) wk; birth weight, 970 (SD 330) g]. Ethane and pentane were quantitated in expired air during the first 18 d of life. During the first 2 postnatal d ethane [24.1 (SEM 7.8) pmol x kg-1 x min-1] and pentane [24.2 (SEM 4.1) pmol x kg-1 x min-1] were stable but increased during d 5 to maxima of 79.1 (15.8) pmol x kg-1 x min-1 and 62.1 (8.1) pmol x kg-1 x min-1, respectively. Maximum ethane and pentane correlated with gestational age (r = -0.42, p = 0.03 and r = -0.52, p = 0.005, respectively) and birth weight (r = -0.38, p = 0.05 and r = -0.59, p = 0.001, respectively). Infants with high maximum expired ethane and pentane (exceeding 40 pmol x kg-1 x min-1) had higher odds of dying or having bronchopulmonary dysplasia than those with low ethane and pentane (odds ratio, 6.5; 95% confidence interval, 1.1 to 38.5; p < 0.05 for ethane and odds ratio, 5.6; 95% confidence interval, 1.1 to 29.3; p < 0.05 for pentane). We conclude that degree of prematurity is the single most important factor explaining free radical-mediated lipid peroxidation in premature infants. A therapeutic intervention to limit the effects of free radicals should be started during the 1st postnatal d in premature infants to be effective.

Branched-chain and mixed amino acid solutions and thermogenesis in postoperative patients

The effect of amino acid composition on the thermogenic response to amino acid infusion was studied in 20 spontaneously breathing postoperative coronary bypass patients and 6 healthy volunteers. On the 1st postoperative day, patients received either a balanced amino acid solution (2510 kJ/24 h) or an amino acid solution consisting primarily (88.8%) of branched-chain amino acids (BCAAs; 2510 kJ/24 h) for 6 h. Another group of patients receiving only hypocaloric glucose served as control subjects. The volunteers randomly received the same balanced amino acid solution (2510 kJ/24 h) or the same BCAA-enriched solution (2510 kJ/24 h) for 6 h. In the coronary bypass patients, both infusion regimens resulted in an increase in resting energy expenditure (REE) (p < 0.01). The thermogenic response to nutrition was 28.5 +/- 5.8 and 46.9 +/- 4.3% (mean +/- SE) in the patients receiving the balanced and BCAA-enriched solutions, respectively (p < 0.05). REE did not change in the control group. Alveolar ventilation increased in both groups (p < 0.05), and the change was more prominent in patients receiving the BCAA-enriched solution. PaCO2 decreased significantly in both nutrition groups. In the healthy subjects, REE increased only during the balanced amino acid infusion (p < 0.05). The thermogenic response to the balanced amino acid solution was 20.7 +/- 4.2% (p < 0.05), whereas no thermogenic response to the BCAA-enriched solution was observed (-5.6 +/- 3.3%, NS). This difference was probably due to the smaller energy cost of BCAA metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)