Can Fraction of Inspired Oxygen Predict Extubation Failure in Preterm Infants?

Background: Prolonged mechanical ventilation in preterm infants may cause complications. We aimed to analyze the variables affecting extubation outcomes in preterm infants at high risk of extubation failure. Methods: This was a single-center, observational, retrospective study. Extubation failure was defined as survival with the need for reintubation within 72 h. Successfully extubated neonates (group 1) were compared to those with failed extubation (group 2). Multivariate logistic regression analysis evaluated factors that predicted extubation outcomes. Results: Eighty infants with a birth weight under 1000 g and/or gestational age (GA) under 28 weeks were included. Extubation failure occurred in 29 (36.2%) and success in 51 (63.8%) neonates. Most failures (75.9%) occurred within 24 h. Pre-extubation inspired oxygen fraction (FiO2) of 27% had a sensitivity of 58.6% and specificity of 64.7% for extubation failure. Post-extubation FiO2 of 32% had a sensitivity of 65.5% and specificity of 62.8% for failure. Prolonged membrane rupture (PROM) and high GA were associated with extubation success in multivariate logistic regression analysis. Conclusions: High GA and PROM were associated with extubation success. Pre-and post-extubation FiO2 values were not significantly predictive of extubation failure. Further studies should evaluate if overall assessment, including ventilatory parameters and clinical factors, can predict extubation success in neonates

A Multicenter Clinical Evaluation of Data Logging in Cochlear Implant Recipients Using Automated Scene Classification Technologies

Currently, there are no studies assessing everyday use of cochlear implant (CI) processors by recipients by means of objective tools. The Nucleus 6 sound processor features a data logging system capable of real-time recording of CI use in different acoustic environments and under various categories of loudness levels. In this study, we report data logged for the different scenes and different loudness levels of 1,366 CI patients, as recorded by SCAN. Monitoring device use in cochlear implant recipients of all ages provides important information about the listening conditions encountered in recipients' daily lives that may support counseling and assist in the further management of their device settings. The findings for this large cohort of active CI users confirm differences between age groups concerning device use and exposure to various noise environments, especially between the youngest and oldest age groups, while similar levels of loudness were observed

Endophytic colonization of grapevine by bacteria reveals a metabolic signature suggesting activation of pathways for symbiosis and defense

Endophytes colonize the inner tissues of plants without causing apparent disease symptoms. In several models of plant-bacteria interactions, it has been suggested that colonization by endophytes occurs in specific parts of the plant. The plant metabolic signature induced by colonizing microbiota can be used to define how this affects the plant’s immune system, growth and health. In grapevine, metabolic responses due to root-colonizing endophytes are yet unclear. To interpret changes in the metabolome composition in planta due to endophytes, we combined i) the study of plant tissue colonization by bacteria using fluorescence in-situ hybridization and ii) the analysis of grapevine’s secondary metabolome to dissect the interactions between plants and their endobiota. We described the colonization of grapevine root tissues by three bacterial endophytes (Sphingomonas sp. SpVs6, Enterobacter ludwigii EnVs6 and Pantoea vagans PaVv7) and showed the heterogeneity of colonization patterns by these strains as well as their strategy for root penetration. After inoculation with strain EnVs6 we detected a plausible metabolic signature in plants consisitng of significant differences in accumulated stilbenes and phenolic compounds. These were differentially concentrated in control and treated plants and inequally distributed between roots and stems. Accumulation of flavonols and phytoalexins occurred mainly in roots due to root inoculation with the three endophytic strains. Such metabolic signature may be linked to an adaptative response to bacterial inoculation, suggesting involvement of the plant’s immune defenses and point at a possible role of metabolites such as phenolic compounds as key for bacterial colonization in symbiotic contexts. The set of phenylpropanoids affected by endophyte inoculation strikingly resemble those previously reported to result in thiamine-mediated resistance to Plasmopara viticola infection. This similarity hints at the mechanistic basis of endophyte-mediated plant immunity and may explain the previously tested efficacy of this strain as a biocontrol agent

Laser microdissection of grapevine leaves highlights site-specific transcriptional changes at the early stages of downy mildew infection

Grapevine (Vitis vinifera) is one of the world’s major fruit crops, but most of the commercial cultivars are susceptible to downy mildew, caused by Plasmopara viticola. Transcript profiling has largely been used to investigate gene expression changes of the interaction between grapevine and P. viticola, but these studies have generally involved the use of RNA from whole grapevine leaves. P. viticola infects grapevine leaves and young berries by stomata and develops intercellular mycelium in the mesophyll. Only a small fraction of leaf cells is in contact with the pathogen at the early stages of infection and the large portion of not-infected cells could mask the transcriptional changes related to defence activation. Laser microdissection (LMD) technique allows the isolation of specific cell types from heterogeneous tissue. LMD was used to specifically collect cells at the site of P. viticola infection or at the adjacent layers from inoculated leaves of in vitro-grown grapevines. Protocols for sample fixation, laser microdissection and RNA isolation from group of cells were optimized and the expression of ten genes involved in the grapevine defence response was analysed by real-time RT-PCR. The expression level of the selected genes was generally greater at the site of infection compared to the whole infected leaf, and expression profiles in infected and adjacent cells differed according to the tested genes. These results get new insights on the activation of specific processes at the sites of P. viticola infection, which were masked in the whole-leaf analysis, and the optimized protocols will be further used for site-specific transcriptomic studies

Laser microdissection of grapevine leaves infected by Plasmopara viticola reveals site-specific defense-related processes

Downy mildew, caused by Plasmopara viticola, is one of the most important diseases of grapevine. P. viticola infects grapevine leaves and young berries by stomata and develops intercellular mycelium in the mesophyll. Gene expression analyses are commonly carried out on whole grapevine leaves at the early stages of infection. However, only a small fraction of leaf cells are in contact with the pathogen, and the large portion of non-infected cells could mask the transcriptional changes related to defence reactions. More accurate information on the modulation of defence-related genes at the site of P. viticola infection could help in better understanding the regulation of the defence at the site of infection and to clarify the reaction of the surrounding tissues. Laser microdissection was used to precisely isolate cells at the site of P. viticola infection and at the adjacent layers from inoculated leaves of in vitro-grown grapevines. Protocols for sample fixation, laser microdissection and RNA isolation from group of cells were optimized, and the expression of genes encoding pathogenesis-related (PR) proteins, transcription factors, and enzymes involved in defence processes was analysed by real-time RT-PCR. The expression of defence-related genes was induced by P. viticola in stomata and in the adjacent cells, and their expression level was greater at the site of infection compared to the whole infected leaf. Our results demonstrated specific activation of defence-related processes at the sites of P. viticola infection, which were masked in the whole-leaf analysis. This optimized protocol can be used for site-specific transcriptomic analysis and it may be also suitable to study plant cell interactions with other pathogens

Can insect pests be vectors of beneficial endophytes?

Insects able to feed on plant vessels are often known to be vectors of plant pathogens. While much is known about the dynamics and ecology of transmission of pathogens, there is very little, if any, knowledge on the transmission of other microorganisms which are not harmful to the host plant. To shed some light on the role of these insects for the ecology of endophytic microorganisms, we used the sap-feeding leafhopper Scaphoideus titanus (vector of the pathogenic Candidatus Phytoplasma vitis) to transmit microorganisms across grapevine plants. S. titanus nymphs were able to transfer the entire bacterial community from adult (donor) plants to bacteria-free micropropagated (acceptor) grapevines. Sequencing of the bacterial 16S rDNA gene unveiled the composition of bacterial endophytic communities in donor plants, vector insects and acceptor plants, and permitted to track the transmission of bacterial communities between insects and plants. After insect feeding, acceptor plants were colonized by complex endophytic communities dominated by Proteobacteria, highly similar to those present in donor plants. Interestingly, a similar bacterial community, but with a higher ratio of Firmicutes, was carried by the insect. When freshly hatched insects fed directly on acceptor plants without prior contact with the donor, they transferred an entirely different bacterial community dominated by Actinobacteria, where the opportunistic human pathogen Mycobacterium abscessus played a major role. Plant roots were also colonized by complex microbial communities as rich as those found in plant stems, despite little or no direct contact with the insect. We demonstrated for the first time the capability of insect vectors to transfer entire bacterial communities across plants. Feeding on adult plants changed the spectrum of bacteria transmitted by the insect. This drastic change may be explained with the acquisition by the insect of the bacterial communities from the donor plant