Reducing tidal volume and increasing positive end-expiratory pressure with constant plateau pressure during one-lung ventilation: effect on oxygenation.

BACKGROUND: It is no longer safe to use large tidal volumes (V(T)) (>8 ml kg(-1)) for one-lung ventilation (OLV), and limiting plateau pressure should be a major objective. Due to the specificity of OLV, the use of positive end-expiratory pressure (PEEP) remains controversial. This study determined whether at the same low plateau pressure, reducing V(T) and increasing PEEP were not inferior to larger V(T) and lower PEEP ventilation in terms of oxygenation. METHODS: This prospective, randomized, non-inferiority, cross-over trial included 88 patients undergoing open thoracotomy who received two successive ventilatory strategies in random order: V(T) (8 ml kg(-1) of ideal body weight) with low PEEP (5 cm H(2)O), or low V(T) (5 ml kg(-1)) with a high PEEP. Respiratory rate and PEEP were, respectively, adjusted to maintain constant ventilation and plateau pressure. The primary endpoint was the ratio under each ventilatory strategy. RESULTS: The non-inferiority of low-V(T) ventilation could not be established. The mean adjusted ratio was lower overall during low-V(T) ventilation, and differences between the two ventilatory modes varied significantly according to baseline (T0). Decreased oxygenation during low V(T) was smaller when baseline values were low. Systolic arterial pressure was not lower during low-V(T) ventilation. CONCLUSION: During OLV, lowering V(T) and increasing PEEP, with the same low plateau pressure, reduced oxygenation compared with larger V(T) and lower PEEP. This strategy may reduce the risk of lung injury, but needs to be investigated further.

Evidence for exopolysaccharide production by Oenococcus oeni strains isolated from non-ropy wines.

AIMS: The aim of this study was to assess the exopolysaccharide (EPS) production capacities of various strains of Oenococcus oeni, including malolactic starters and strains recently isolated from wine. METHODS AND RESULTS: Fourteen O. oeni strains displaying or not (PCR check on genomic DNA) the gtf gene generally associated with beta-glucan formation and ropiness were grown on grape juice medium, dialysed MRS-derived medium or synthetic medium. The soluble polysaccharides (PS) remaining in the culture supernatant were alcohol precipitated, and their concentration was quantified by the phenol-sulfuric method. Most of the O. oeni strains studied produced significant amounts of EPS, independently of their genotype (gtf+ or gtf-). The EPS production was not directly connected with growth and could be stimulated by changing the growth medium composition. The molecular weight distribution analysis and attempts to determine the PS chemical structure suggested that most strains produce a mixture of EPS. CONCLUSION: Oenococcus oeni strains recently isolated from wine or cultivated for many generations as a malolactic starter are able to produce EPS other than beta-glucan. SIGNIFICANCE AND IMPACT OF THE STUDY: These EPS may enhance the bacteria survival in wine (advantage for malolactic starters) and may contribute to the wine colloidal equilibrium.

Pressure-controlled ventilation and intrabronchial pressure during one-lung ventilation.

BACKGROUND: Pressure-controlled ventilation (PCV) has been suggested to reduce peak airway pressure (P(peak)) and intrapulmonary shunt during one-lung ventilation (OLV) when compared with volume-controlled ventilation (VCV). At the same tidal volume (V(T)), the apparent difference in P(peak) is mainly related to the presence of a double-lumen tracheal tube. We tested the hypothesis that the decrease in P(peak) observed in the breathing circuit is not necessarily associated with a decrease in the bronchus of the dependent lung. METHODS: This observational study included 15 consecutive subjects who were ventilated with VCV followed by PCV at constant V(T). Airway pressure was measured simultaneously in the breathing circuit and main bronchus of the dependent lung after 20 min of ventilation. RESULTS: PCV induced a significant decrease in P(peak) [mean (sd)] measured in the breathing circuit [36 (4) to 26 (3) cm H(2)0, P<0.0001] and in the bronchus [23 (4) to 22 (3) cm H(2)O, P=0.01]. However, the interaction (ventilatory mode x site of measurement) revealed that the decrease in P(peak) was significantly higher in the circuit (P<0.0001). Although the mean percentage decrease in P(peak) was significant at both sites, the decrease was significantly lower in the bronchus [5 (6)% vs 29 (3)%, P<0.0001]. CONCLUSIONS: During PCV for OLV, the decrease in P(peak) is observed mainly in the respiratory circuit and is probably not clinically relevant in the bronchus of the dependent lung. This challenges the common clinical perception that PCV offers an advantage over VCV during OLV by reducing bronchial P(peak).

Effect of antiplaque compounds and mouthrinses on the activity of glucosyltransferases from Streptococcus sobrinus and insoluble glucan production.

INTRODUCTION: The development of therapeutic agents inhibiting the activity of glucosyltransferases (GTF) and their production of glucans is a potential strategy to reduce dental decay. The aim of this study was first to characterize a GTF preparation from Streptococcus sobrinus ATCC 33478 and then to evaluate the effects of select compounds and mouthrinses on insoluble glucan (ISG) formation by combined GTFs. METHODS: The purity of the crude GTF mixture was assessed by electrophoresis. The effects of pH, temperature, sucrose, and dextran T10 concentrations on GTF activity were analyzed and the chemical structure of the products was investigated. Finally, the inhibition of GTF by commercial mouthrinses used in oral hygiene and their active components (chlorhexidine, polyphenolic compounds, fluoride derivatives, polyols, cetylpyridinium chloride, and povidone iodine) was analyzed through the reductions in the overall reaction rate and the quantity of ISG synthesized. RESULTS: The S. sobrinus ATCC 33478 crude GTF preparation obtained contains a mixture of four different GTFs known for this species. For optimal adherent ISG formation, the reaction parameters were 37 degrees C, pH 6.5, sucrose 50 g/l, and dextran T10 2 g/l. Under these conditions, the most effective agents were chlorhexidine, cetylpyridinium chloride, and tannic acid. Eludril, Elmex, and Betadine were the most effective inhibitors of all the mouthrinses tested. CONCLUSION: As the formulation of commercial products considerably influences the efficiency of active components, the fast representative ISG inhibition test developed in this study should be of great interest.

Agaricus bisporus susceptibility to bacterial blotch in relation to environment: biochemical studies.

Variation of Agaricus bisporus susceptibility to bacterial blotch in relation to environment was studied at the biochemical level. Significant differences were observed between A. bisporus strains for tyrosinase and gamma-glutamyl transferase (GGT) activities and for gamma-L(+)glutaminyl-4-hydroxybenzene (GHB) content. A lower effect was detected for compost quality. GGT activity and GHB content were related to strain susceptibility to bacterial blotch by a linear model depending on strain type, commercial or wild.

Fruit Resistance to Colletotrichum acutatum in Strawberries.

Evaluation of strawberry resistance to anthracnose is generally limited to the crown rot phase of the disease. The major objective of this study was to develop a screening test for resistance to anthracnose fruit rot (Colletotrichum acutatum) using detached strawberries under controlled-environment conditions. Inoculation was carried out on detached fruits harvested at the stage when they were turning white-pink. Lesion diameter and percentage of diseased fruits (disease incidence) were measured. An incubation temperature of 18°C allowed a better discrimination between resistant and susceptible genotypes than 25°C. At 18°C and 8 days after inoculation, 26 genotypes differed greatly in susceptibility to anthracnose fruit rot, and lesion size ranged from 0 to 17 mm with disease incidence of 10 to 100%. A relationship between lesion size and disease incidence was established. The 26 genotypes were classified into three groups of susceptibility according to lesion size and percentage of diseased fruits. The susceptible group included nine genotypes with lesion sizes of 8.2 to 14.4 mm and 81 to 100% diseased fruits. In this group, Pajaro and Elsanta were the most susceptible. The four genotypes belonging to the resistant group, Dover, Capitola, US159, and US438, showed small fruit lesion sizes of 0.4 to 1.0 mm and a limited disease incidence (10 to 17%). The resistance of two genotypes to anthracnose fruit rot was evaluated under field conditions (plastic tunnel). The relatively resistant genotype, Sequoia, displayed reduced incidence of anthracnose fruit rot in the sections closest to the source of inoculum compared with the susceptible genotype Elsanta.

Pulmonary alveolar proteinosis requiring "hybrid" extracorporeal life support, and complicated by acute necrotizing pneumonia.

Pulmonary alveolar proteinosis (PAP), which was first described by Rosen in 1958, is a rare disease characterized by impaired surfactant metabolism that provokes the accumulation of proteinaceous material in the alveoli. PAP is usually an auto-immune disease though, less commonly, may be congenital or secondary to another underlying disorder, such as infection, an immunodeficiency or a haematological disease. A positive diagnosis can be made with the appearance of "crazy-paving" on a computed tomography scan, with a milky fluid bronchial aspiration. A cytological examination will also show eosinophilic material and pink stained periodic acid-Schiff-positive material. A whole lung lavage is the most widely accepted therapy for hypoxemic PAP. Herein, we report the case of a 27-year-old woman admitted into our intensive care unit for hypoxemic PAP that was complicated by a pulmonary embolism. Because the patient presented with refractory hypoxemia associated with a brief cardiac arrest, femoral veno-arterial extracorporeal life support (ECLS) was rapidly inserted. Under ECLS, the patient subsequently developed "Harlequin syndrome", which was managed using an original and minimally invasive method. A whole lung lavage as well as prone positioning was effectively performed under ECLS, and resulted in substantial improvement in oxygenation. The patient could be discharged from the hospital 40 days later.

[Effectiveness of a recruitment manoeuvre and positive end-expiratory pressure on respiratory mechanics during laparoscopic bariatric surgery]. / Efficacité d'une manoeuvre de recrutement alvéolaire associée à une pression expiratoire positive sur la mécanique respiratoire en coeliochirurgie bariatrique.

OBJECTIVE: To evaluate recruitment manoeuvre (RM) efficiency associated with a 10 cmH(2)O positive end expiratory pressure (PEEP) on respiratory mechanic estimated by lung compliance (Ctp) and PEEP to ZEEP expiratory volume delta (Delta VTE) during laparoscopic bariatric surgery in patients with morbid obesity. STUDY DESIGN: Prospective randomized study. METHODS: Twenty-six obese patients (BMI>40 kg/m(2)) undergoing laparoscopic bariatric surgery. The recruitment group received an RM followed by a 10 cmH(2)O PEP versus only 10 cmH(2)O PEP in the control group. Ctp was measured during the intervention and functional residual capacity (FRC) was estimated measuring Delta VTE during a PEP to ZEP manoeuvre. Mann and Whitney tests as well as a t-test were used (significance p<0.05). RESULTS: In the RM group, a significant improvement of 52+/-14 ml/cmH(2)O was noted versus a 36+/-10 ml/cmH(2)O in the PEP group (p=0,004). This improvement was transitory and no statistically significant Delta VTE difference was noted between the groups at the end of the intervention (360 [90-770]ml [MRA] and 310 [190-450]ml [PEP]). CONCLUSION: In patients with morbid obesity undergoing laparoscopic bariatric surgery, an RM conducted prior the pneumoperitoneum temporarily improves lung mechanics but without any change of the end expiratory lung volume at the end of the surgery in comparison with PEP alone. The RM was well tolerated.

[Experience of intensive care by medical and nursing staff in transplantation units]. / Vécu de la réanimation par les soignants en services de transplantation.

Findings of this paper are responses from more than eighty paramedic staff members or transplantation departments (multi-organs, adults-children) in formation. It concerns three points: specific intensive care for corpses whose organs are to be extracted (teams/relatives); staff in operating rooms where extractions are carried out taking into account cultural anthropology (rituals, ethics, legal aspects); intensive care for new grafts with experimental protocols (children, mucoviscidosis, heart-lungs, small intestine). Two perspectives are set forth successively on the basis of psychoanalysis and anthropology. The scope of closeness and remoteness is a key means to approach the problems inherent in grafts, parallel to the immunologic principle. The extraction of organs causes symbolic and cultural given to appear, leading to the elaboration of fantasies isclosure of archaisms and its fears. So, the positive dynamics of grafts requires a structuring cultural process to preserve their success and intensification.

A quantitative trait locus of Agaricus bisporus resistance to Pseudomonas tolaasii is closely linked to natural cap color.

A quantitative trait locus (QTL) of resistance to Pseudomonas tolaasii was detected in Agaricus bisporus using a cross between a wild strain from the Sonoran desert and a cultivated strain. The resistance QTL was strongly linked with the brown color allele of PPC1. This QTL explained about 30% of the variation observed for living bacteria-induced symptoms. The use of bacterial toxin did not reproduce living bacteria symptoms but revealed the same QTL. The latter QTL was not affected by environmental variation. No relation was found between the resistance QTL and the tyrosinase gene, which is involved in the browning process.

Factors affecting alpha,-1,2 glucooligosaccharide synthesis by Leuconostoc mesenteroides NRRL B-1299 dextransucrase.

The optimization of alpha-1,2 glucooligosaccharide (GOS) synthesis from maltose and sucrose by Leuconostoc mesenteroides NRRL B-1299 dextransucrase was achieved using experimental design and consecutive analysis of the key parameters. An increase of the pH of the reaction from 5.4 to 6.7 and of the temperature from 25 to 40 degrees C significantly favored alpha-1,2 GOS synthesis, thanks to a significant decrease of the side reactions, i.e., dextran and leucrose synthesis. These positive effects were not sufficient to compensate for the decrease of enzyme stability caused by the use of high pH and temperature. However, the critical parameters were the sucrose to maltose concentration ratio (S/M) and the total sugar concentration (TSC). Alpha1,2 GOS synthesis was favored at high S/M ratios. But using these conditions also led to an increase of side reactions which could be modulated by choosing the appropriate TSC. Finally, with S/M = 4 and TSC = 45% w/v, dextran and leucrose productions were limited and the final alpha-1,2 GOS yield reached 56.7%, the total GOS yield being 88%.

Reactor optimization for alpha-1,2 glucooligosaccharide synthesis by immobilized dextransucrase.

The immobilization of dextransucrase in Ca-alginate beads relies on the close association between dextran polymer and dextransucrase. However, high amounts of dextran in the enzyme preparation drastically limit the specific activity of the immobilized enzyme (4 U/mL of alginate beads). Moreover, even in the absence of diffusion limitation at the batch conditions used, the enzyme behavior is modified by entrapment so that the dextran yield increases and the alpha-1,2 glucooligosaccharides (GOS) are produced with a lower yield (46.6% instead of 56.7%) and have a lower mean degree of polymerization than with the free dextransucrase. When the immobilized catalyst is used in a continuous reaction, the reactor flow rate necessary to obtain high conversion of the substrates is very low, leading to external diffusion resistance. As a result, dextran synthesis is even higher than in the batch reaction, and its accumulation within the alginate beads limits the operational stability of the catalyst and decreases glucooligosaccharide yield and productivity. This effect can be limited by using reactor columns with length to diameter ratio > or =20, and by optimizing the substrate concentrations in the feed solution: the best productivity obtained was 3.74 g. U(-1). h(-1), with an alpha-1,2 GOS yield of 36%.

Evidence for PPC1, a determinant of the pilei-pellis color of Agaricus bisporus fruitbodies.

In the present study, we investigated the genetic basis of mushroom cap color. In first generation hybrids between a brown isolate and the white commercial hybrid U 1, the white trait was recessive. Color was determined using color meter technology in second generation hybrids obtained by crossing the homokaryotic progeny of a first generation hybrid with a homokaryon from U 1. Statistical analysis revealed a bimodal distribution describing two classes of white and not-white hybrids. We postulate that a recessive allele at a single locus (PPC1) encodes the white pilei-pellis color. Joint segregation analyses indicated that PPC1 was linked to the ADH (alcohol dehydrogenase) locus. Through the analysis of the heterokaryotic progeny of the first generation hybrid, a recombination model is proposed in which PPC1 is located between the centromere and the ADH locus.