Trail pheromones: an integrative view of their role in social insect colony organization.

Trail pheromones do more than simply guide social insect workers from point A to point B. Recent research has revealed additional ways in which they help to regulate colony foraging, often via positive and negative feedback processes that influence the exploitation of the different resources that a colony has knowledge of. Trail pheromones are often complementary or synergistic with other information sources, such as individual memory. Pheromone trails can be composed of two or more pheromones with different functions, and information may be embedded in the trail network geometry. These findings indicate remarkable sophistication in how trail pheromones are used to regulate colony-level behavior, and how trail pheromones are used and deployed at the individual level.

Feasibility of non-invasive pressure support ventilation in infants with respiratory failure after extubation: a pilot study.

OBJECTIVE: To evaluate the feasibility and effects of non-invasive pressure support ventilation (NIV) on the breathing pattern in infants developing respiratory failure after extubation. DESIGN: Prospective pilot clinical study; each patient served as their own control. SETTING: A nine-bed paediatric intensive care unit of a tertiary university hospital. PATIENTS: Six patients (median age 5 months, range 0.5-7 months; median weight 4.2 kg, range 3.8-5.1 kg) who developed respiratory failure after extubation. INTERVENTIONS: After a period of spontaneous breathing (SB), children who developed respiratory failure were treated with NIV. MEASUREMENTS AND RESULTS: Measurements included clinical dyspnoea score (DS), blood gases and oesophageal pressure recordings, which were analysed for respiratory rate (RR), oesophageal inspiratory pressure swing (dPes) and oesophageal pressure-time product (PTPes). All data were collected during both periods (SB and NIV). When comparing NIV with SB, DS was reduced by 44% (P < 0.001), RR by 32% (P < 0.001), dPes by 45% (P < 0.01) and PTPes by 57% (P < 0.001). A non-significant trend for decrease in PaCO(2) was observed. CONCLUSION: In these infants, non-invasive pressure support ventilation with turbine flow generator induced a reduction of breathing frequency, dPes and PTPes, indicating reduced load of the inspiratory muscles. NIV can be used with some benefits in infants with respiratory failure after extubation.

Intérêt du monitorage du CO2 expiré pour évaluer la PaCO2 lors d'insuffisance respiratoire aiguë hypercapnique traitée par ventilation non invasive.

Introduction: L'efficacité d'une séance de VNI est habituellement évaluée selon la réponse clinique, l'amélioration de l'acidose respiratoire et de l'hypercapnie. Le but de cette étude était d'évaluer l'intérêt de la mesure du CO2 en fin d'expiration (PETCO2) pour estimer la PaCO2 et son évolution dans le temps. Patients et Méthodes: Des patients de réanimation souffrant d'une insuffisance respiratoire aiguë hypercapnique (PaCO2 >45 mmHg) ont été inclus dans cette étude prospective. La PETCO2était mesurée à l'aide d'un capteur nasobuccal (SmartLine®, Oridion) au cours d'une séance de VNI de 60 minutes. Une gazométrie artérielle et la valeur de PETCO2 étaient enregistrées au début de la séance puis chaque 15 minutes. Des manoeuvres d'expiration complète passives et actives étaient effectuées à 30 et 60 minutes. Le gradient de CO2 (PaCO2- PETCO2) a été calculé pour l'ensemble des mesures, spécifiquement pour chaque manoeuvre d'expiration complète, ainsi qu'individuellement pour chaque patient. Ces grandeurs sont exprimées en moyenne et écart-type pour évaluer le biais et la dispersion observés entre PaCO2 et PETCO2. La différence entre chaque valeurs consécutives de gradient de CO2 (delta gradient de CO2) a été calculées par patient. Cette mesure quantifie la variation au cours du temps du gradient de CO2 pour un patient donné. Résultats: 11 patients ont été inclus (7 BPCO, 1 restrictif et 1 syndrome d'apnée du sommeil). Sur l'ensemble des mesures, le gradient de CO2 était de 14.7 + 10.6 mmHg, lors des manoeuvres d'expiration complètes active il était de 8.1 + 13.0 mmHg, et de 8.8 + 11.9 mmHg lors des expirations passives. Conclusion: Chez les patients présentant une insuffisance respiratoire aiguë hypercanique traitée par VNI, la mesure de la PETCO2 par capteur nasobuccal ne permet de prédire ni la valeur de PaCO2, ni son évolution dans le temps. Les manoeuvres d'expiration complète n'apportent aucune plus value.

Shift in cytotype frequency and niche space in the invasive plant Centaurea maculosa.

Polyploidy is often assumed to increase the spread and thus the success of alien plant species, but few empirical studies exist. We tested this hypothesis with Centaurea maculosa Lam., a species native to Europe and introduced into North America approximately 120 years ago where it became highly invasive. We analyzed the ploidy level of more than 2000 plants from 93 native and 48 invasive C. maculosa populations and found a pronounced shift in the relative frequency of diploid and tetraploid cytotypes. In Europe diploid populations occur in higher frequencies than tetraploids and only four populations had both cytotypes, while in North America diploid plants were found in only one mixed population and thus tetraploids clearly dominated. Our results showed a pronounced shift in the climatic niche between tetraploid populations in the native and introduced range toward drier climate in North America and a similar albeit smaller shift between diploids and tetraploids in the native range. The field data indicate that diploids have a predominately monocarpic life cycle, while tetraploids are often polycarpic. Additionally, the polycarpic life-form seems to be more prevalent among tetraploids in the introduced range than among tetraploids in the native range. Our study suggests that both ploidy types of C. maculosa were introduced into North America, but tetraploids became the dominant cytotype with invasion. We suggest that the invasive success of C. maculosa is partly due to preadaptation of the tetraploid cytotype in Europe to drier climate and possibly further adaptation to these conditions in the introduced range. The potential for earlier and longer seed production associated with the polycarpic life cycle constitutes an additional factor that may have led to the dominance of tetraploids over diploids in the introduced range.

Discovery and molecular characterization of an ambisense densovirus from South American populations of Solenopsis invicta

In an effort to discover viruses as classical biological control agents, a metatranscriptomics/pyrosequencing approach was used to survey native Solenopsis invicta collected exclusively in Argentina. A new virus was discovered with characteristics consistent with the family Parvoviridae, subfamily Densovirinae. The virus, tentatively named Solenopsis invicta densovirus (SiDNV), represents the first DNA virus discovered in ants (Formicidae) and the first densovirus in a hymenopteran insect. The ambisense genome was 5280 nucleotides in length and the termini possessed asymmetrically positioned inverted terminal repeats, formed hairpin loops, and had transcriptional regulatory elements including CAAT and TATA sites. Phylogenetic analysis revealed that SiDNV belongs to a group that includes two other densoviruses found in insects (Acheta domestica densovirus and Planococcus citri densovirus). SiDNV was prevalent in fire ants from Argentina but completely absent in fire ants found in the USA indicating that this virus has potential for biological control of introduced S. invicta.

Host genetics of invasive Aspergillus and Candida infections.

Invasive candidiasis and aspergillosis are major complications in surgical and onco-hematological patients, and still associated with an important morbidity and mortality. A large number of studies highlighted the potential role of host genetic polymorphisms that may influence susceptibility to fungal pathogens, but many were limited by insufficient statistical power, problematic design, and/or lack of replication. However, some relevant polymorphisms are now emerging from well-conducted studies whose associations have been replicated and/or are supported by strong biological evidence. Such polymorphisms together with other biomarkers may play a role in the prediction, diagnosis, and management of severe fungal infections in high-risk patients in the coming years.

Intérêt de l'échographie du diamètre de l'enveloppe du nerf optique pour la détection non invasive de l'hypertension intracrânienne [Interest of optic nerve sheath diameter ultrasonography in dectecting non-invasively raised intracranial pressure].

Intracranial hypertension is an emergency suspected from clinical symptoms, imaging data and ophthalomologic signs. Intracranial hypertension is confirmed by invasive intracranial monitoring, which is the gold standard technique to measure intracranial pressure (ICP). Because of complications, hemorrhage or infection, non-invasive methods have been developed such as neuroimaging, transcranial Doppler sonography and optic nerve sheath diameter (ONSD) ultrasonography. We have reviewed ONSD technique that detects intracranial hypertension related volume variations of subarachnoid space along the retro bulbar segment of the optic nerve. Technique, indications and prospects are discussed.

Occam's razor in minimally invasive pituitary surgery: tailoring the endoscopic endonasal uninostril trans-sphenoidal approach to sella turcica.

BACKGROUND: Since the introduction of the endoscopic endonasal approaches in the field of skull base surgery during the last two decades, several variants of the sella turcica endoscopic surgery have been described. The aim of this study is to provide a stepwise description of one of these variants in a minimally invasive/maximally efficient perspective. METHOD: For the majority of our sella turcica pathologies, we have progressively adopted a uninostril endoscopic approach that is very conservative towards the nasal mucosa with a very limited mucosal incision, resection of the vomer and allowing an almost ad integrum sellar floor reconstruction, without compromising the efficacy and completeness of both surgical oncologic and endocrine targets. CONCLUSION: The uninostril trans-sphenoidal endoscopic endonasal approach to sella turcica is tailored to ally maximal efficiency and minimal invasiveness.

Identification and potential origin of invasive clawed frogs Xenopus (Anura: Pipidae) in Sicily based on mitochondrial and nuclear DNA

African clawed frogs of the widespread polytypic species Xenopus laevis Daudin, 1802 (ranging large parts of sub-Saharan Africa) have been spreading since the 1940s, and have established reproductive populations in Europe, Asia and the Americas, where they can have negative impact as competitors of native amphibians and as disease vectors for chytridomycosis or ranaviruses. Here we use two mitochondrial (cytochrome b, 16S rDNA) and one nuclear (RAG 1: Recombination Associated Gene 1) DNA markers to infer the potential origin of invasive clawed frogs from Sicily that represent the largest invasive population in Europe. Identical mtDNA haplotypes match with those of Xenopus laevis, and Sicilian clawed frogs very probably belong to a lineage from the Cape Region of South Africa, most likely originating from a laboratory stock. Nuclear data support this conclusion. Identical mtDNA sequences (cyt b, 16S) of frogs sampled across their range in Sicily suggest the occurrence of a single source population and a potential bottleneck at their release, but faster evolving multilocus nuclear data (microsatellites, SNPs) on the population genetics would be important in the future to better support this hypothesis

Successful combined minimally invasive direct coronary artery bypass and transapical aortic valve implantation.

Transapical aortic valve implantation is indicated in high-risk patients with aortic stenosis and peripheral vascular disease requiring aortic valve replacement. Minimally invasive direct coronary artery bypass grafting is also a valid, minimally invasive option for myocardial revascularization in patients with critical stenosis on the anterior descending coronary artery. Both procedures are performed through a left minithoracotomy, without cardiopulmonary bypass, aortic cross-clamping, and cardioplegic arrest. We describe a successful combined transapical aortic valve implantation and minimally invasive direct coronary bypass in a high-risk patient with left anterior descending coronary artery occlusion and severe aortic valve stenosis.

" Arabidopsis Thaliana " response to insect feeding : new components controlling defense gene expression and plant resistance

Abstract: Plants cannot run away to escape attacking herbivores, but they defend themselves by producing anti-digestive proteins and toxic compounds (for example glucosinolates). The first goal of this thesis was to study changes in gene expression after insect attack using microarrays. The responses of Arabidopsis thaliana to feeding by the specialist Pieris rapae and the generalist Spodoptera liffora is were compared. We found that the transcript profiles after feeding by the two chewing insects were remarkably similar, although the generalist induced a slightly stronger response. The second goal was to evaluate the implication of the four signals jasmonic acid (JA), salicylic acid (SA), ethylene (ET), and abscisic acid (ABA) in the control of insect-regulated gene expression. Using signaling mutants, we observed that JA was the predominant signal and that ABA modulated defense gene expression. In contrast, SA and ET appeared to control slightly gene expression, but only after feeding by S. litforalis. The third goal was to establish whether plant responses are really effective against insects. In accordance with the transcript profile, both insects were affected by the JA-dependent defenses, as they performed better on the JA-insensitive mutant. S. littoralis also performed better on ABA-deficient mutants, providing evidence for the role of ABA in defense against insects. When testing indole or aliphatic glucosinolate deficient mutants, we found that they were also more susceptible to insect feeding, providing some of the first genetic evidence for the defensive role of glucosinolates in planta. Finally, a glutathione-deficient mutant, pad2-1, was also more susceptible to insect feeding and we could attribute this phenotype to a lowered accumulation of the major indole glucosinolate. In this thesis, we provide a comprehensive list of insect-regulated genes, including many transcription factors that constitute interesting candidate genes for the further study of insect-induced expression changes. Understanding how the plant responses to insects are regulated will provide tools for a better management of insect pest in the field. Résumé: Les plantes ne peuvent s'échapper pour fuir les insectes qui les attaquent, mais elles se défendent en produisant des protéines anti-digestives et des composés toxiques (par exemple des glucosinolates). Le premier but de cette thèse était d'étudier les changements de l'expression génétique lors d'attaque par des insectes en utilisant des puces à ADN. Nous avons comparé la réponse d'Arabidopsis thaliana à deux espèces d'insectes avec des habitudes alimentaires différentes : le spécialiste Pieris rapae et le généraliste Spodoptera littoralis. Nous avons trouvé que les profils de transcription après l'attaque par les deux insectes sont remarquablement similaires, bien que le généraliste induise une réponse légèrement plus forte. Le deuxième but était de déterminer l'implication de quatre signaux dans le contrôle de la réponse :l'acide jasmonique (JA), l'acide salicylique (SA), l'éthylène (ET), et l'acide abscissique (ABA). En utilisant de mutants de signalisation, nous avons montré que l'acide jasmonique était le signal prédominant et que l'acide abscissique modulait l'expression génétique. D'autre part, l'acide salicylique et l'éthylène contrôlent à un degré moindre l'expression génétique, mais seulement après l'attaque par S. littoralís. Le troisième but était d'établir si les réponses des plantes sont efficaces contre les insectes. En accord avec le profil de transcription, les deux espèces d'insectes se sont mieux développées sur un mutant insensible au JA, indiquant que les défenses contrôlées par ce signal sont cruciales pour la plante. De plus, les larves de S. littorales se sont mieux développées sur des mutants déficients en ABA, ce qui fournit une preuve du rôle de l'acide abscissique dans la défense contre les insectes. En testant des mutants déficients en glucosinolates de type indole ou aliphatique, nous avons trouvé qu'ils étaient plus sensibles aux insectes, démontrant ainsi le rôle défensif des glucosinolates in planta. Finalement, le mutant déficient en glutathion pad2-1 était aussi plus sensible à l'attaque des insectes, et nous avons pu attribuer ce phénotype à une plus faible augmentation d'un indole glucosinolate dans ce mutant. Dans cette thèse, nous avons mis en évidence un nombre important de gènes contrôlés par les insectes, comprenant de nombreux facteurs de transcription qui constituent des candidats intéressants pour`étudier plus en détail les changements d'expression génétique induits par les insectes. Une meilleure compréhension de la réponse des plantes contre l'attaque des insectes devrait nous permettre de développer de nouvelles stratégies pour mieux gérer les ravageurs des cultures.