Carbon Dioxide Flush of an Integrated Minimized Perfusion Circuit Prior to Priming Prevents Spontaneous Air Release Into the Arterial Line During Clinical Use.

Recently, an oxygenator with an integrated centrifugal blood pump (IP) was designed to minimize priming volume and to reduce blood foreign surface contact even further. The use of this oxygenator with or without integrated arterial filter was compared with a conventional oxygenator and nonintegrated centrifugal pump. To compare the air removal characteristics 60 patients undergoing coronary artery bypass grafting were alternately assigned into one of three groups to be perfused with a minimized extracorporeal circuit either with the conventional oxygenator, the oxygenator with IP, or the oxygenator with IP plus integrated arterial filter (IAF). Air entering and leaving the three devices was measured accurately with a bubble counter during cardiopulmonary bypass. No significant differences between all groups were detected, considering air entering the devices. Our major finding was that in both integrated devices groups incidental spontaneous release of air into the arterial line in approximately 40% of the patients was observed. Here, detectable bolus air (>500 µm) was shown in the arterial line, whereas in the minimal extracorporeal circulation circuit (MECC) group this phenomenon was not present. We decided to conduct an amendment of the initial design with METC-approval. Ten patients were assigned to be perfused with an oxygenator with IP and IAF. Importantly, the integrated perfusion systems used in these patients were flushed with carbon dioxide (CO2 ) prior to priming of the systems. In the group with CO2 flush no spontaneous air release was observed in all cases and this was significantly different from the initial study with the group with the integrated device and IAF. This suggests that air spilling may be caused by residual air in the integrated device. In conclusion, integration of a blood pump may cause spontaneous release of large air bubbles (>500 µm) into the arterial line, despite the presence of an integrated arterial filter. CO2 flushing of an integrated cardiopulmonary bypass system prior to priming may prevent spontaneous air release and is strongly recommended to secure patient safety.

Extraction of soil solution by drainage centrifugation-effects of centrifugal force and time of centrifugation on soil moisture recovery and solute concentration in soil moisture of loess subsoils.

The solute concentration in the subsoil beneath the root zone is an important parameter for leaching assessment. Drainage centrifugation is considered a simple and straightforward method of determining soil solution chemistry. Although several studies have been carried out to determine whether this method is robust, hardly any results are available for loess subsoils. To study the effect of centrifugation conditions on soil moisture recovery and solute concentration, we sampled the subsoil (1.5-3.0 m depth) at commercial farms in the loess region of the Netherlands. The effect of time (20, 35, 60, 120 and 240 min) on recovery was studied at two levels of the relative centrifugal force (733 and 6597g). The effect of force on recovery was studied by centrifugation for 35 min at 117, 264, 733, 2932, 6597 and 14,191g. All soil moisture samples were chemically analysed. This study shows that drainage centrifugation offers a robust, reproducible and standardised way for determining solute concentrations in mobile soil moisture in silt loam subsoils. The centrifugal force, rather than centrifugation time, has a major effect on recovery. The maximum recovery for silt loams at field capacity is about 40%. Concentrations of most solutes are fairly constant with an increasing recovery, as most solutes, including nitrate, did not show a change in concentration with an increasing recovery.

Diagnostic Accuracy of an Algorithm for Discriminating Presumed Solid and Gaseous Microembolic Signals During Transcranial Doppler Examinations.

OBJECTIVE: The aim of the work described here was to assess the diagnostic accuracy of a new algorithm (SGA-a) for time-domain analysis of transcranial Doppler audio signals to discriminate presumed solid and gaseous microembolic signals and artifacts (SGAs). METHODS: SGA-a was validated by human experts in an artifact cohort of 20 patients subjected to a 1-h transcranial Doppler exam before cardiac surgery (cohort 1). Emboli were validated in a cohort of 10 patients after aortic valve replacement in a 4-h monitoring period (cohort 2). The SGA misclassification rate was estimated by testing SGA-a on artifact-free test files of solid and gaseous emboli. RESULTS: In cohort 1 (n = 24,429), artifacts were classified with an accuracy of 94.5%. In cohort 2 (n = 12,328), the accuracy in discriminating solid/gaseous emboli from artifacts was 85.6%. The 95% limits of agreement for, respectively, the numbers of presumed solids and gaseous emboli, artifacts and microembolic signals of undetermined origin were [-10, 10], [-14, 7] and [-9, 16], and the intra-class correction coefficients were 0.99, 0.99 and 0.99, respectively. The rate of misclassification of solid test files was 2%, and the rate of misclassification of gaseous test files was 12%. CONCLUSION: SGA-a can detect presumed solid and gaseous microembolic signals and differentiate them from artifacts. SGA-a could be of value when both solid and gaseous emboli may jeopardize brain function such as seen during cardiac valve and/or aortic arch replacement procedures.

Safety and effectiveness of selective carotid angioplasty prior to cardiac surgery: a single-centre matched case-control study.

OBJECTIVES: Reducing the rate of postoperative stroke after cardiac surgery remains challenging, especially in patients with occlusive cerebrovascular disease. Angioplasty in all patients with high-grade carotid artery stenosis has not been shown to be effective in reducing the post-surgical stroke rate. In this study, we present the initial results of a different approach using selective carotid angioplasty only in patients with poor intracranial collaterals. METHODS: We conducted a single-centre study to assess the safety of this procedure. The postangioplasty complication rate of the study group was compared to that of patients who were scheduled for symptomatic carotid artery angioplasty. To determine the effectiveness of this procedure, the post-cardiac surgery complication rate of the study group was compared with that of the matched case controls. RESULTS: Twenty-two patients were treated with selective carotid angioplasty without developing persistent major neurological complications. All patients except 1 patient subsequently underwent surgery without developing persistent major neurological disabilities. Two patients died of cardiogenic shock within 30 days. CONCLUSIONS: Selective carotid angioplasty prior to cardiac surgery in patients with a presumed high risk of stroke was relatively safe and effective in this study group. Although this strategy does not prevent stroke in these high-risk patients, data suggest that this approach shifts the postoperative type of stroke from a severe haemodynamic stroke towards a minor embolic stroke with favourable neurological outcomes. Larger studies are needed to determine whether this strategy can effectively eliminate the occurrence of haemodynamic stroke after cardiac surgery.

Influence of the intercalated cations on the surface energy of montmorillonites: consequences for the morphology and gas barrier properties of polyethylene/montmorillonites nanocomposites.

Organically modified montmorillonites obtained by cation exchange from the same natural layered silicate were studied. The surface properties of the pristine and a series of organically modified clays were determined by inverse gas chromatography and the water adsorption mechanisms were studied by a gravimetric technique coupled with a microcalorimeter. A significant increase of the specific surface area, a decrease of the water adsorption, and a decrease of the dispersive component of the surface energy were observed when the sodium cations of the natural montmorillonite were exchanged for a quaternary ammonium. Slighter differences in surface properties were observed, on the other hand, between the different types of organically modified montmorillonites. Indeed, similar dispersive components of the surface energy were determined on the organoclays. Nevertheless, the specific surface area increased in the range 48-80 m(2)/g with increasing d-spacing values and the presence of specific groups attached to the quaternary ammonium, such as phenyl rings or hydroxyl groups, led to some specific behaviors, i.e., a more pronounced base character and a higher water adsorption at high activity, respectively. Differences in interlayer cation chain organization, denoted as crystallinity, were also observed as a function of the nature of the chains borne by the quaternary ammonium. In a later step, polyethylene-based nanocomposites were prepared with those organically modified montmorillonites. The clay dispersion and the barrier properties of the nanocomposites were discussed as a function of the montmorillonite characteristics and of the matrix/montmorillonite interactions expected from surface energy characterization.

Impact of the Haga Braincare Strategy on the burden of haemodynamic and embolic strokes related to cardiac surgery.

OBJECTIVES: This study prospectively evaluates the impact of the Haga Braincare Strategy (HBS) on the occurrence of haemodynamic and embolic stroke in a cohort of patients who underwent coronay artery bypass grafting (CABG), valve replacement of a combination of both types of surgery between 2012 and 2015 at the Haga Teaching Hospitals. METHODS: The HBS is a dual strategy based on a preoperative vascular work-up of the cerebral circulation by transcranial Doppler and a perioperative monitoring of the cerebral circulation by cerebral oximetry. Duplex of the carotid arteries and/or computed tomography angiography prior to surgery was performed in high-risk patients. Patients with severe carotid artery stenosis were scheduled for carotid angioplasty prior to surgery or waived from surgery. RESULTS: A total of 1065 patients were included. Poor cerebral haemodynamics were identified by transcranial Doppler in 2.1% of patients (n = 22). Based on the HBS, 3 patients were waived from surgery, 4 received preoperative carotid angioplasty followed by cardiac surgery and the remaining patients were operated while being monitored with bilateral cerebral oximetry sensors. In all, 2.2% of the study group experienced a stroke (n = 23), of which none were classified as haemodynamic. Most of the remaining presumed embolic strokes showed a minor to moderate stroke severity. CONCLUSIONS: In this single-centre prospective follow-up study, surveillance of cerebral perfusion by the HBS eliminated the occurrence of haemodynamic stroke while most of the residual strokes had a good to favourable prognosis.

Solvent-based nanocomposite coatings I. Dispersion of organophilic montmorillonite in organic solvents.

This study aims to determine the relevant parameters controlling the organophilic montmorillonite dispersion in various organic solvents which can be used as dispersion media for polymer coatings. These suspensions were studied at three scales: At nanometer scale by looking to interlayer distance: When the solvent surface energy is higher than the organophilic clay surface energy, i.e., gamma solvent > or = gamma montmorillonite, the intercalated organic chains of the quaternary ammonium modifier swell, leading to an increase of the interlayer distance. The balance between hydrophilic and hydrophobic character is the key to dispersion of nanoclays. At micrometer scale by studying the rheological behaviour of clay suspensions: Gels are formed by percolation of microgels, based on swollen 3-4 platelet tactoids. The viscoelastic properties and the flow behavior reveal the gel structuration by measuring the gel stiffness and the flowing stress. At macroscopic scale analyzed from the swelling of the nanoclay into solvents: The compatibility between solvent and organophilic clay governs the macroscopic swelling, i.e., interactions between organic chains borne by the intercalated ions and solvents govern the final suspension morphologies. The same methodology can be adopted for monomers or prepolymers selected for one in situ intercalation/exfoliation processing route.

Social affinities as the basis of the social organization of a Pyrenean chamois (Rupicapra pyrenaica) population in an open mountain range.

The tendencies of different age and sex classes to flock with each other were analysed in a Pyrenean chamois (Rupicapra pyrenaica) population of southern France, on the basis of the distribution of groups into various types and sizes. The strongest inter-attraction is undoubtedly that existing between adult females and kids, even if each age and sex class also associates easily with itself. Yearlings globally seem to have lower affinities with adults of both sexes than with their own class, but, in any case, the lowest inter-attraction is between adult females and males. These social affinities, varying in detail, actually remain roughly the same through the seasons. However, the most important point is that they seem sufficient to explain the main characteristics of the social structure of the studied Pyrenean chamois population in open habitat; it does not seem necessary to hypothesize complicated individual 'choices' or 'preferences' to explain it. This allows for a systemic approach of such a population, considering individuals as simple elements, which permits us to understand the basis of sociality and to explain inter-populational differences.

Seasonal movements of female Corsican mouflon (Ovis ammon) in a Mediterranean mountain range, southern France.

The spatial occupation of female Corsican mouflon (Ovis ammon) in medium Mediterranean mountains of southern France, was studied between the end of 1987 and June 1989. It can be divided into two seasonal home ranges, one in fall/winter, and one in spring/summer. Both seasonal home ranges start with a period of intense locomotive activity in the different individuals. This behaviour could be explained by a general inclination of the animals to move on large scale, the expression of this inclination being allowed by the favourable environmental conditions in spring and fall. In any case, the comparison of our results with those obtained from mountain populations of the genus Ovis, suggests that 'phylogenetic inertia' exists towards certain modalities in spatial occupation. Indeed, the observed seasonal movements do not seem to retain a real adaptive character in our Mediterranean study area, as shown by the overlap of ranges, the use of the same type of habitat during the seasons and the great variability between individuals.

Theoretical possibility of a genetic assimilation of the feeeing direction in Talitrus saltator.

Reports on the genetic assimilation of features involving behaviour are very scarce, while they are more common in the fields of morphology and physiology. This paper investigates the theoretical possibility of a genetic assimilation of the 'fleeing direction' in the sandhopper (Talitrus saltator), consistent with Bateson's model of genetic assimilation. This is done from the two simple genetic determinations suggested by L. Pardi and F. Scapini to explain the variability of the feature between populations. The conditions for this genetic assimilation to occur are examined and particular attention is paid to the differences between the properties of the two determinations. Finally, the possible importance of genetic assimilation in the field of animal orientation is discussed.

Areas of concentrated use within seasonal ranges of Corsican mouflons: Importance of psychophysiological and ecological contexts in their modulation.

We studied the space use of mouflons (Ovis musimon) for more than four years in a population living in low Mediterranean mountains. The different behaviour of ewes and rams, which is related to social and spatial segregation outside the rut, has an effect on spatial use. Depending on the season, ecological or psychophysiological contexts influence the way in which the animals concentrate their activity in their range. The difference in spatial use between sexes is the most obvious during the rut and in winter. During the rut, rams exhibit a high degree of spatial instability while ewes continue as in summer, concentrating their activity in a restricted area. During winter, rams which have returned to their non-rut range exhibit spatial stability while females become more unstable. We suggest that spatial attachment of the two sexes is expressed differently and that the significance accorded by individuals to the psychophysiological and ecological contexts they live play on the significance of space and finally on spatial use.

Perception and learning in evolution.

Different theoretical models and methods exist which help to tackle the question of perception and learning in evolution. Waddington's genetic assimilation and its counterpart, the 'Wright Effect', provide a good methodological framework for experiments and simulations. Comparative analysis, in which phylogenetic as well as ecological aspects are considered, is another useful tool. These approaches consider cognitive processes with their simultaneous involvement in selective processes; they say very little about their emergence.

Inter-individual associations and social structure of a mouflon population (Ovis orientalis musimon).

We analysed individual associations between mouflon (Ovis orientalis musimon) observed during one year in order to find ontogenetic patterns underlying the social structure of the population. A correspondence factorial analysis was performed on Simpson's coefficients to compare association profiles. No strong association was found between adults but some of the young adult females maintained a preferential bond with their mother until the age of three. Yearling males were firstly unstable in their social relations and subsequently developed a strong preference for peers (the preferred companion(s) of young adult males were always young adult males). Animals did not prefer to associate with other individuals of their own family (Wilcoxon test: n = 53; z = 0.463; a < 0.01). Localized abundant food sources caused large regroupings during spring. This was the only case where we noted a series of observations where the same unrelated animals were seen together. With the exception of the mother-offspring relationship, individual social preferences were based on the sex and age of the partner rather than on identity. The existence of social behaviour profiles dependent on sex and age is proposed to explain the above results.

Self-healable interfaces based on thermo-reversible Diels-Alder reactions in carbon fiber reinforced composites.

Thermo-reversible Diels-Alder (DA) bonds formed between maleimide and furan groups have been used to generate an interphase between carbon fiber surface and an epoxy matrix leading to the ability of interfacial self-healing in carbon:epoxy composite materials. The maleimide groups were grafted on an untreated T700 carbon fiber from a three step surface treatment: (i) nitric acid oxidization, (ii) tetraethylenepentamine amination, and (iii) bismaleimide grafting. The furan groups were introduced in the reactive epoxy system from furfuryl glycidyl ether. The interface between untreated carbon fiber and epoxy matrix was considered as a reference. The interfacial shear strength (IFSS) was evaluated by single fiber micro-debonding test. The debonding force was shown to have a linear dependence with embedded length. The highest healing efficiency calculated from the debonding force was found to be about 82% more compared to the value for the reference interface. All the interphases designed with reversible DA bonds have a repeatable self-healing ability. As after the fourth healing, they can recover a relatively high healing efficiency (58% for the interphase formed by T700-BMI which is oxidized for 60 min during the first treatment step).

Long-term results of reoperation for left atrioventricular valve regurgitation after correction of atrioventricular septal defects.

BACKGROUND: Long-term results of reoperation for left atrioventricular valve regurgitation (LAVVR) after previous correction of atrioventricular septal defect (AVSD) are scarce. We evaluated long-term outcome of reoperation for LAVVR and identified risk factors for reoperation. METHODS: Between December 1976 and July 2006, 45 of 312 patients with correction of different AVSDs underwent reoperation for LAVVR. The cohort of 267 patients who did not need reoperation for LAVVR allowed for the identification of risk factors for reoperation and evaluation of overall survival after primary AVSD repair in a competing risk scenario. Clinical data were obtained by retrospective review. RESULTS: The left atrioventricular valve (LAVV) was repaired in 31 patients (68.9%) and replaced in 14 (31.1%). There were 3 in-hospital deaths (6.7%) and 2 late deaths (4.4%). Estimated overall survival was 88.1% at 15 years after the reoperation, and estimated incidence of death after reoperation in the total patient cohort was 2% at 15 years after the primary AVSD repair. Overall survival was significantly higher after LAVV repair than after replacement (p=0.010). Ten patients with LAVV repair required a second reoperation for LAVVR. At follow-up, survivors were in New York Heart Association functional class I (n=36) or II (n=4). Independent risk factors for first reoperation for LAVVR were associated cardiovascular anomalies (p<0.001), LAVV dysplasia (p<0.001), and nonclosure of the cleft (p=0.027). CONCLUSIONS: After previous correction of AVSD, LAVVR can usually be corrected by valve repair. A very dysplastic valve may necessitate replacement. Overall survival is higher after repair than after replacement. In general, overall survival of patients reoperated on for LAVVR is favorable. The overall mortality rate after primary repair of AVSD is explained only for a small part by mortality after reoperation for LAVVR.

More than 30 years' experience with surgical correction of atrioventricular septal defects.

BACKGROUND: Outcome of surgical correction of atrioventricular septal defects (AVSD) still varies despite enhanced results. We reviewed our 30-year experience with AVSD repair and identified risk factors for mortality and reoperation. METHODS: Between 1975 and 2006, 312 patients underwent surgery for complete AVSD (n = 209; 67.0%), partial AVSD (n = 76; 24.4%), or intermediate AVSD (n = 27; 8.6%). Mean age was 2.4 ± 3.9 years; 142 patients (45.5%) were younger than 6 months. Follow-up was 99.0% complete. RESULTS: There were 26 in-hospital deaths (8.3%) and 6 late deaths (2.1% of 283). Estimated overall survival for the total study population was 91.3%, 90.6%, and 88.6% at 1, 5, and 15 years, respectively. In the multivariable logistic regression analysis, surgical era 1975 to 1995 (p < 0.001) and younger age (p = 0.004) were found to be independent risk factors for early mortality, whereas preoperative AV valve insufficiency showed a tendency toward statistical significance (p = 0.052). Of the hospital survivors, 43 patients required a late reoperation. Estimated freedom from late reoperation was 96.4%, 89.3%, and 81.8% at 1, 5, and 15 years, respectively. Multivariable Cox regression analysis showed associated cardiovascular anomalies (p < 0.001), left AV valve dysplasia (p < 0.001), and absence of cleft closure (p = 0.003) to be independent risk factors for late reoperation. CONCLUSIONS: AVSD repair can be accomplished with good long-term results. Early surgical era, associated cardiovascular anomalies, left AV valve dysplasia, and absence of cleft closure negatively influence survival and risk of reoperation.

Results of surgical repair of atrioventricular septal defect with double-orifice left atrioventricular valve.

OBJECTIVE: The outcome of surgical correction of atrioventricular septal defect with double-orifice left atrioventricular valve has improved in recent years but is still reported to be associated with high mortality and reoperation rates. Controversy exists about the management of the accessory orifice. We evaluated our results with correction of atrioventricular septal defect with double-orifice left atrioventricular valve. METHODS: Between 1975 and 2006, 21 patients underwent correction of atrioventricular septal defect with double-orifice left atrioventricular valve. Clinical data were obtained by means of retrospectively reviewing inpatient and outpatient medical records. To evaluate the influence of double-orifice left atrioventricular valve on mortality and the need for reoperation, a comparison was made with 291 consecutive patients who, during the same period, underwent correction of atrioventricular septal defect without double-orifice left atrioventricular valve. RESULTS: None of the 21 patients with double-orifice left atrioventricular valve had undergone a previous operation. The accessory orifice was managed with different techniques depending on the severity of the regurgitation. There was no in-hospital mortality, and there were 3 late deaths. Seven patients required 12 reoperations, 7 for left atrioventricular valve insufficiency. Double-orifice left atrioventricular valve had no influence on mortality but was a significant predictor for reoperation compared with repair of atrioventricular septal defect without double-orifice left atrioventricular valve. At the latest follow-up, all 18 survivors were in New York Heart Association functional class capital I, Ukrainian without medication. Only 1 patient showed residual mild left atrioventricular valve insufficiency. CONCLUSION: Atrioventricular septal defect with double-orifice left atrioventricular valve can be repaired with low mortality. However, double-orifice left atrioventricular valve is a predictor for reoperation. The accessory orifice is often competent and should then be left untouched. If regurgitation of the accessory orifice is present, this is best managed with suture or patch closure.

28 years' experience with transatrial-transpulmonary repair of atrioventricular septal defect with tetralogy of Fallot.

BACKGROUND: The outcome of surgical correction of atrioventricular septal defect and tetralogy of Fallot has improved in recent years but is still reported to be associated with high mortality. Controversy exists about the need of a right ventriculotomy or a right ventricular to pulmonary artery conduit. The purpose of this study was to evaluate our results of atrioventricular septal defect and tetralogy of Fallot repair by transatrial-transpulmonary approaches. METHODS: Between 1979 and 2007, 20 consecutive patients underwent correction of atrioventricular septal defect and tetralogy of Fallot. Five patients had undergone prior palliative shunts. In all patients, a transatrial-transpulmonary approach was used and repair was accomplished without a conduit. The two-patch technique was used to correct the atrioventricular septal defect. Clinical data were obtained by retrospective review of inpatient and outpatient clinical charts. RESULTS: There was no in-hospital mortality and one late, noncardiac death. Six patients required eight reoperations, six for left atrioventricular valve insufficiency (repair: n = 4; replacement: n = 2), one for residual ventricular septal defect, and one for pulmonary artery branch obstruction. Follow-up was complete for all patients (median, 17 years; range, 1.5 to 28 years). All 19 survivors were in good clinical condition at last control, without medication, and in New York Heart Association class I (n = 18) or II (n = 1). Transesophageal echocardiography revealed good right ventricular function, low right ventricular outflow tract gradients (mean, 9 +/- 7.4 mm Hg), and trace pulmonary valve insufficiency (n = 11). CONCLUSIONS: Atrioventricular septal defect and tetralogy of Fallot can be repaired with low mortality by the transatrial-transpulmonary approach without the use of a conduit.

Response of isolated axonal preparations to hyperosmoticity: evidence for a cellular volume regulation.

When submitted to a hyperosmotic stress, isolated axons of Callinectes sapidus shrink. Volume regulation is observed if the experiment is carried out by using serum from a crab adapted to sea water. 3' : 5'-AMP and dibutyryl AMP are also effective. A compound isolated from the hemolymph and having a molecular weight close to 10 000 mimics the effects of the serum and induces a partial regulation of the axonal volume.