Comparative transcriptomics of rice reveals an ancient pattern of response to microbial colonization.

Glomalean fungi induce and colonize symbiotic tissue called arbuscular mycorrhiza on the roots of most land plants. Other fungi also colonize plants but cause disease not symbiosis. Whole-transcriptome analysis using a custom-designed Affymetrix Gene-Chip and confirmation with real-time RT-PCR revealed 224 genes affected during arbuscular mycorrhizal symbiosis. We compared these transcription profiles with those from rice roots that were colonized by pathogens (Magnaporthe grisea and Fusarium moniliforme). Over 40% of genes showed differential regulation caused by both the symbiotic and at least one of the pathogenic interactions. A set of genes was similarly expressed in all three associations, revealing a conserved response to fungal colonization. The responses that were shared between pathogen and symbiont infection may play a role in compatibility. Likewise, the responses that are different may cause disease. Some of the genes that respond to mycorrhizal colonization may be involved in the uptake of phosphate. Indeed, phosphate addition mimicked the effect of mycorrhiza on 8% of the tested genes. We found that 34% of the mycorrhiza-associated rice genes were also associated with mycorrhiza in dicots, revealing a conserved pattern of response between the two angiosperm classes.

Propionibacterium acnes: An Underestimated Pathogen in Implant-Associated Infections.

The role of Propionibacterium acnes in acne and in a wide range of inflammatory diseases is well established. However, P. acnes is also responsible for infections involving implants. Prolonged aerobic and anaerobic agar cultures for 14 days and broth cultures increase the detection rate. In this paper, we review the pathogenic role of P. acnes in implant-associated infections such as prosthetic joints, cardiac devices, breast implants, intraocular lenses, neurosurgical devices, and spine implants. The management of severe infections caused by P. acnes involves a combination of antimicrobial and surgical treatment (often removal of the device). Intravenous penicillin G and ceftriaxone are the first choice for serious infections, with vancomycin and daptomycin as alternatives, and amoxicillin, rifampicin, clindamycin, tetracycline, and levofloxacin for oral treatment. Sonication of explanted prosthetic material improves the diagnosis of implant-associated infections. Molecular methods may further increase the sensitivity of P. acnes detection. Coating of implants with antimicrobial substances could avoid or limit colonization of the surface and thereby reduce the risk of biofilm formation during severe infections. Our understanding of the role of P. acnes in human diseases will likely continue to increase as new associations and pathogenic mechanisms are discovered.

In Vivo Systematic Analysis of Candida albicans Zn2-Cys6 Transcription Factors Mutants for Mice Organ Colonization.

The incidence of fungal infections in immuno-compromised patients increased considerably over the last 30 years. New treatments are therefore needed against pathogenic fungi. With Candida albicans as a model, study of host-fungal pathogen interactions might reveal new sources of therapies. Transcription factors (TF) are of interest since they integrate signals from the host environment and participate in an adapted microbial response. TFs of the Zn2-Cys6 class are specific to fungi and are important regulators of fungal metabolism. This work analyzed the importance of the C. albicans Zn2-Cys6 TF for mice kidney colonization. For this purpose, 77 Zn2-Cys6 TF mutants were screened in a systemic mice model of infection by pools of 10 mutants. We developed a simple barcoding strategy to specifically detect each mutant DNA from mice kidney by quantitative PCR. Among the 77 TF mutant strains tested, eight showed a decreased colonization including mutants for orf19.3405, orf19.255, orf19.5133, RGT1, UGA3, orf19.6182, SEF1 and orf19.2646, and four an increased colonization including mutants for orf19.4166, ZFU2, orf19.1685 and UPC2 as compared to the isogenic wild type strain. Our approach was validated by comparable results obtained with the same animal model using a single mutant and the revertant for an ORF (orf19.2646) with still unknown functions. In an attempt to identify putative involvement of such TFs in already known C. albicans virulence mechanisms, we determined their in vitro susceptibility to pH, heat and oxidative stresses, as well as ability to produce hyphae and invade agar. A poor correlation was found between in vitro and in vivo assays, thus suggesting that TFs needed for mice kidney colonization may involve still unknown mechanisms. This large-scale analysis of mice organ colonization by C. albicans can now be extended to other mutant libraries since our in vivo screening strategy can be adapted to any preexisting mutants.

Assessing the associations between mental disorders, cardiovascular risk factors, and cardiovascular disease : the CoLaus/PsyCoLaus study

Background: Cardio-vascular diseases (CVD), their well established risk factors (CVRF) and mental disorders are common and co-occur more frequently than would be expected by chance. However, the pathogenic mechanisms and course determinants of both CVD and mental disorders have only been partially identified.Methods/Design: Comprehensive follow-up of CVRF and CVD with a psychiatric exam in all subjects who participated in the baseline cross-sectional CoLaus study (2003-2006) (n=6'738) which also included a comprehensive genetic assessment. The somatic investigation will include a shortened questionnaire on CVRF, CV events and new CVD since baseline and measurements of the same clinical and biological variables as at baseline. In addition, pro-inflammatory markers, persistent pain and sleep patterns and disorders will be assessed. In the case of a new CV event, detailed information will be abstracted from medical records. Similarly, data on the cause of death will be collected from the Swiss National Death Registry. The comprehensive psychiatric investigation of the CoLaus/PsyCoLaus study will use contemporary epidemiological methods including semi-structured diagnostic interviews, experienced clinical interviewers, standardized diagnostic criteria including threshold according to DSM-IV and sub-threshold syndromes and supplementary information on risk and protective factors for disorders. In addition, screening for objective cognitive impairment will be performed in participants older than 65 years.Discussion: The combined CoLaus/PsyCoLaus sample provides a unique opportunity to obtain prospective data on the interplay between CVRF/CVD and mental disorders, overcoming limitations of previous research by bringing together a comprehensive investigation of both CVRF and mental disorders as well as a large number of biological variables and a genome-wide genetic assessment in participants recruited from the general population.

Biology and pathogenicity of "Chlamydia"- related organisms

Abstract : This thesis investigates the pathogenicity and biology of Parachlamydia acanthamoebae and other obligate intracellular bacteria related to chlamydiae. All these Chlamydia-like organisms replicate in amoebae. Some evolved to resist to macrophages and represent possible new agents of respiratory tract infection. Using serological and molecular approaches, we showed that Parachlamydia acanthameobae likely plays a role as an etiological agent of pneumonia [1,2]. We also showed that Parachlamydia was able to enter and survive within pneumocytes and lung fibroblasts [3]. Moreover, we developed an animal model of lung infection in mice, which fulfilled the third and fourth Koch postulate [4]. Given the likely role of Parachlamydia in pneumonia, we studied its antibiotic susceptibility. We showed that Chlamydia-related organisms were resistant to quinolones, mainly due to mutations in the QRDR of gyrA [5]. To have tools to investigate the role of other Chlamydia-related bacteria in pneumonia, we developed immunofluorescence assays and assessed the rate of serological cross-reactivity between all these Chlamydia-related bacteria [6]. We also developed new diagnostic specific PCRs [2,7] and sequenced additional genes that are useful for both taxonomic and diagnostic purposes [8]. Then, we applied these serological and molecular approaches to patients with and without respiratory tract infections. This led to the identification of a possible role of Protochlamydia naegleriophila [7] and of Waddlia chondrophila in pneumonia [1]. A significant part of the thesis also investigated interactions of Parachlamydia with macrophages [9] and the host range of Chlamydia-related bacteria [10]. In conclusion, there are growing body of evidence supporting the role of Chlamydia-like organisms as agents of pneumonia. Further studies are needed to precise their pathogenic role in this setting. The diagnostic tools developed during this thesis will be useful to investigate the role of these strict intracellular bacteria in other diseases in both humans and animals [11,12]. Résumé : Le but de cette thèse est de déterminer le rôle pathogène de Parachlamydia et des bactéries apparentées aux Chlamydia ainsi que d'étudier leur biologie. Parachlamydia acanthamoebae est une bactérie intracellulaire apparentée aux Chlamydia, et qui est résistante non seulement aux amibes mais aussi aux macrophages. Par une approche sérologique et moléculaire, nous avons montré que les bactéries apparentées aux Chlamydia jouent probablement un rôle comme agent de pneumonie [1,2]. De plus, nous avons démontré que P. acanthameobae est capable d'entrer et de survivre dans les pneumocytes et fibroblastes pulmonaires [3]. Nous avons ensuite développé un modèle animal remplissant les troisième et quatrième postulats de Koch [4]. Nous avons aussi démontré que les bactéries apparentées aux Chlamydia sont résistantes aux quinolones, en raison de mutations dans la région QRDR de gyrA [5]. Afin de mieux déterminer le rôle pathogène de ces bactéries, nous avons mis au point des techniques d' immunofluorescence et déterminé la cross-réaction sérologique entre les différentes bactéries apparentées aux Chlamydia [6]. Différentes PCR diagnostiques ont aussi été développées [2,7] et des gènes supplémentaires ont été séquencés, qui seront utiles à la taxonomie ainsi qu'au développement de nouvelles méthodes diagnostiques [8]. Ces méthodes ont été appliquées à des échantillons provenant de patient avec ou sans pneumonie et ont permis l'identification du possible rôle pathogène de Protochlamydia naegleriophila [7] et de Waddlia chondrophila [1]. L'interaction de Parachlamydia avec les macrophages [9] et la permissivité de différentes cellules aux bactéries apparentées aux Chlamydia [10] ont également été étudiés dans le cadre de cette thèse. En conclusion, plusieurs nouveaux éléments viennent renforcer l'hypothèse que les bactéries apparentées aux Chlamydia sont des agents de pneumonies. Cependant, d'autres études doivent être menées pour confirmer leur rôle dans cette maladie. Les méthodes diagnostiques développées ici seront très utiles pour déterminer le rôle pathogène de ces bactéries chez les humains et animaux [11,12]

Reassessing the role of Staphylococcus aureus clumping factor and fibronectin-binding protein by expression in Lactococcus lactis.

Since Staphylococcus aureus expresses multiple pathogenic factors, studying their individual roles in single-gene-knockout mutants is difficult. To circumvent this problem, S. aureus clumping factor A (clfA) and fibronectin-binding protein A (fnbA) genes were constitutively expressed in poorly pathogenic Lactococcus lactis using the recently described pOri23 vector. The recombinant organisms were tested in vitro for their adherence to immobilized fibrinogen and fibronectin and in vivo for their ability to infect rats with catheter-induced aortic vegetations. In vitro, both clfA and fnbA increased the adherence of lactococci to their specific ligands to a similar extent as the S. aureus gene donor. In vivo, the minimum inoculum size producing endocarditis in > or =80% of the rats (80% infective dose [ID80]) with the parent lactococcus was > or =10(7) CFU. In contrast, clfA-expressing and fnbA-expressing lactococci required only 10(5) CFU to infect the majority of the animals (P < 0.00005). This was comparable to the infectivities of classical endocarditis pathogens such as S. aureus and streptococci (ID80 = 10(4) to 10(5) CFU) in this model. The results confirmed the role of clfA in endovascular infection, but with a much higher degree of confidence than with single-gene-inactivated staphylococci. Moreover, they identified fnbA as a critical virulence factor of equivalent importance. This was in contrast to previous studies that produced controversial results regarding this very determinant. Taken together, the present observations suggest that if antiadhesin therapy were to be developed, at least both of the clfA and fnbA products should be blocked for the therapy to be effective.

An integrated genetic and functional analysis of the role of type II transmembrane serine proteases (TMPRSSs) in hearing loss.

Building on our discovery that mutations in the transmembrane serine protease, TMPRSS3, cause nonsyndromic deafness, we have investigated the contribution of other TMPRSS family members to the auditory function. To identify which of the 16 known TMPRSS genes had a strong likelihood of involvement in hearing function, three types of biological evidence were examined: 1) expression in inner ear tissues; 2) location in a genomic interval that contains a yet unidentified gene for deafness; and 3) evaluation of hearing status of any available Tmprss knockout mouse strains. This analysis demonstrated that, besides TMPRSS3, another TMPRSS gene was essential for hearing and, indeed, mice deficient for Hepsin (Hpn) also known as Tmprss1 exhibited profound hearing loss. In addition, TMPRSS2, TMPRSS5, and CORIN, also named TMPRSS10, showed strong likelihood of involvement based on their inner ear expression and mapping position within deafness loci PKSR7, DFNB24, and DFNB25, respectively. These four TMPRSS genes were then screened for mutations in affected members of the DFNB24 and DFNB25 deafness families, and in a cohort of 362 sporadic deaf cases. This large mutation screen revealed numerous novel sequence variations including three potential pathogenic mutations in the TMPRSS5 gene. The mutant forms of TMPRSS5 showed reduced or absent proteolytic activity. Subsequently, TMPRSS genes with evidence of involvement in deafness were further characterized, and their sites of expression were determined. Tmprss1, 3, and 5 proteins were detected in spiral ganglion neurons. Tmprss3 was also present in the organ of Corti. TMPRSS1 and 3 proteins appeared stably anchored to the endoplasmic reticulum membranes, whereas TMPRSS5 was also detected at the plasma membrane. Collectively, these results provide evidence that TMPRSS1 and TMPRSS3 play and TMPRSS5 may play important and specific roles in hearing.

Cell-cell communication in the biocontrol strain Pseudomonas fluorescens CHA0

Summary Pseudomonas fluorescens CHAO is a soil bacterium which was isolated near Morens (Switzerland) and which protects plants from root-pathogenic fungi. This protection is due to extracellular secondary metabolites whose synthesis is regulated by the two-component system GacS/GacA in strain CHAO. Extracellular signals of bacterial origin activate this regulatory system. These signals are different from N-acyl-homoserine lactones, are extracted by dichloromethane and appear to have a low molecular weight. Preliminary evidence was obtained from a small molecule m/z 278 produced by strain CHAO. Similar signals capable of activating GacS/GacA-dependent regulation in strain CHAO were found in a large number of different Gram-negative bacteria. Once activated by signal(s), the sensor GacS is assumed to phosphorylate the response regulator GacA, which positively influences a regulatory cascade, resulting in the synthesis of secondary metabolites. This cascade includes three GacA-controlled small regulatory RNAs and two translational repressor proteins. The regulatory RNAs titrate the repressor proteins; this allows translation of target genes and the synthesis of exoenzymes and secondary metabolites such as antibiotics and hydrogen cyanide. A GFP-based sensor for signal detection was constructed in strain CHAO by fusing the gfp reporter gene to the rsmZ small RNA gene. CHAO mutants defective for signal production were isolated following transposon insertion mutagenesis. In one class of mutants obtained, the gacS gene was inactivated, indicating that GacS/GacA positively controls signal production. In a second class, the thiC gene required for thiamine (vitamin B1) biosynthesis was disrupted. Addition of excess (> 10E-6 M) thiamine to the medium restored signal production. By contrast, when the thiamine concentration was just sufficient to allow normal growth, no production of signal(s) was observed. The mechanism by which thiamine activates signal production remains to be elucidated. Résumé Pseudomonas fluorescens CHAO est une bactérie du sol, isolée près de Morens (Suisse), qui a la capacité de protéger les plantes contre des champignons pathogènes de la racine. Cette protection provient de métabolites secondaires excrétés par la bactérie, dont la synthèse est régulée par le système à deux composants GacS/GacA. Des signaux extracellulaires d'origine bactérienne activent ce système de régulation. Ces signaux, différents des N-acyl¬homosérines lactones, sont extraits par le dichlorométhane et semblent avoir une petite masse moléculaire. Une molécule (masse m/z 278) a été mise en évidence par des expériences préliminaires chez la souche CHAO. Des signaux similaires, capables d'activer la régulation dépendante de GacS/GacA chez la souche CHAO, ont été trouvés chez un grand nombre de bactéries à Gram négative. Une fois activé par le(s) signal(aux), le senseur GacS est supposé phosphoryler le régulateur de réponse GacA, qui influence positivement la cascade de régulation menant à la synthèse des métabolites secondaires. Cette cascade inclut trois petits ARNs régulateurs contrôlés par GacA et deux protéines répresseurs de la traduction. Les ARNs régulateurs titrent les protéines répresseurs, ce qui permet la traduction des gènes cibles et la synthèse d'exoenzymes et de métabolites secondaires tel les antibiotiques et le cyanure d'hydrogène. Un senseur basé sur la GFP pour la détection de signaux a été construit dans la souche CHAO en fusionnant le gène rapporteur gfp au gène de petit ARN rsmZ. Des mutants de CHAO déficients pour la production de signaux ont été isolés au moyen d'une mutagenèse par insertion de transposon. Chez une classe de mutants obtenus, le gène gacS a été inactivé, indiquant que GacS/GacA contrôle positivement la production de signaux. Dans une seconde classe, le gène thiC nécessaire à la biosynthèse de thiamine (vitamine B1) a été interrompu. L'addition en excès (> 10E-6 M) de thiamine au milieu restaure la production de signaux. A l'opposé, quand la concentration de thiamine est juste suffisante pour permettre une croissance normale, aucune production de signaux n'a été observée. Le mécanisme par lequel la thiamine active la production de signaux reste à élucider.

Characterization of a plant-derived peptide displaying water clarifying and antimicrobial activities

SUMMARY Drinking water is currently a scarce world resource, the preparation of which requires complex treatments that include clarification of suspended particles and disinfection. Seed extracts of Moringa oleifera Lam., a tropical tree, have been proposed as an environment- friendly alternative, due to their traditional use for the clarification of drinking water. However, the precise nature of the active components was unknown. Here, we show that recombinant or synthetic forms of a cationic seed polypeptide mediate efficient sedimentation of suspended mineral particles and bacteria. Unexpectedly, the polypeptide was also found to possesses a bactericidal activity capable of disinfecting heavily contaminated water. Furthermore, the polypeptide has been shown to efficiently kill several pathogenic bacteria, including antibiotic-resistant isolates of Pseudomona, Streptococcus and Legionella species. Structural modeling of the peptide coupled to the functional analysis of synthetic peptide derivatives delineated distinct structural determinants for the flocculation and antibacterial activities. Our results suggest that a glutamine-rich portion of the polypeptide is involved in the sedimentation process; alternatively, the antibacterial activity depends on a amphiphilic loop. Assembly of multiple copies of this loop into a branched peptide derivative strongly enhances antibacterial activity without displaying hemolytic effect. In conclusion, this polypeptide displays the unprecedented feature of combining efficient water purification and disinfectant properties indicating different molecular mechanisms involved in each case. This work not only identified the features responsible for these activities but also provides useful information that has implications for the further development of this cationic polypeptide as a potent antibacterial agent. RESUME L'eau potable est actuellement une ressource limitée dans le monde. La production d'eau propre à la consommation exige des traitements complexes, incluant la clarification des particules en suspension ainsi que sa désinfection par des additifs chimiques. Les extraits de la graine d'un arbre tropical, Moringa oleifera, sont utilisés traditionnellement en Afrique afin de clarifier l'eau. Quoique la nature exacte des composants actifs était inconnue, on a pu mettre en évidence un polypeptide cationique contenu dans ces graines, capable de sédimenter de manière efficace des particules minérales en suspension ainsi que des bactéries. Ce travail a aussi mis en évidence que ce polypeptide a une activité bactéricide, permettant une désinfection d'eau fortement contaminée. De plus, nous avons démontré que ce polypeptide est efficace contre de nombreuses souches bactériennes pathogènes, également celles résistantes aux antibiotiques comme Pseudomonas, Streptococcus et Legionella. L'analyse de la structure moléculaire de ce polypeptide, couplée à son analyse fonctionnelle a mis en évidence deux domaines structuraux distinct, un pour l'activité de floculation et l'autre pour l'activité antibactérienne. Nos résultats suggèrent que le domaine riche en glutamine est impliqué dans le processus de sédimentation et que l'activité antimicrobienne dépend d'un domaine formant une boucle amphiphilique. En ramifiant plusieurs copies de cette boucle on a pu augmenter de manière significative l'activité antibactérienne. En conclusion, nous avons pu démontrer que ce polypeptide à la capacité unique de combiner des propriétés de purification et de désinfection de l'eau, ce qui implique des mécanismes moléculaires distincts pour ces deux activités. Ce travail a permis d'identifier les domaines du polypeptide qui sont responsables de ses activités et offre une perspective pour le développement d'un nouvel agent antimicrobien.

Maternal and paternal contributions to pathogen resistance dependent on development stage in a whitefish (Salmonidae)

It is often assumed that maternal and paternal contributions to offspring phenotype change over the lifetime of an individual. However, studies on parental effects typically suffer from the problems that heritabilities and maternal environmental effects are difficult to separate, and that both may depend on environmental factors and developmental stage. In order to experimentally disentangle maternal from paternal contributions and the likely effects of developmental stage from ecological effects, we sampled a natural population of the whitefish Coregonus palaea, used gametes for full-factorial in vitro fertilizations, raised over 10000 of the resulting offspring singly at controlled conditions, and exposed them at different points during embryonic development to one of two strains of Pseudomonas fluorescens that differed in their virulence characteristics (only one caused mortality, while both delayed hatching and reduced growth). Vulnerability to infection increased markedly over embryo development. This change coincided with a distinct shift in the importance of maternal to additive genetic effects on survival. Timing of exposure also affected the variance components for hatching time and larval length, but in a less consistent direction than the variance components for mortality. No significant genetic variation was found for any reaction norms across time points of exposure, indicating a uniformity among genotypes in how susceptibility changed over development. Phenotypes were also typically correlated across time points, which could constrain the evolution of the reaction norms. Our experiment demonstrates that the relative maternal and paternal contributions to susceptibility to an infection, and hence the evolutionary potential to respond to pathogen-induced selection, depends not only on the kind of pathogenic stress but also on the timing of the challenge.

Le concept de test relationnel en psychothérapie: origine, développements et applications aux troubles de la personnalité = The test concept in psychotherapy: origins, developments and application to personality disorders

Le concept de test relationnel (test, en anglais ; Weiss et Sampson, 1986 [16]) est présenté. Ses origines dans les écrits de Freud sont brièvement retracées et son inscription dans la théorie des croyances pathogènes de Weiss présentée. Par ailleurs, les autres éléments de la théorie psychanalytique de Weiss sont présentés (buts thérapeutiques, obstacles, traumas, insight, test relationnel). Toutes ces étapes sont illustrées par des exemples tirés de la littérature. Un développement récent du concept de test relationnel est présenté et appliqué à la psychothérapie des troubles de la personnalité (Sachse, 2003 [14]). Finalement, les auteurs donnent deux brefs exemples de tests relationnels tirés de leur propre pratique de psychothérapeute et discutent des modèles en les comparant entre eux. Des conclusions concernant l'utilité du concept de test relationnel pour la pratique psychothérapeutique et la recherche en psychothérapie sont proposées. The test concept (Weiss and Sampson, 1986 [16]) is presented. Its origins in Freud's works are briefly evoked and its place within the theory of pathogenic beliefs by Weiss presented. We present also the remaining elements of Weiss' psychoanalytic theory which are objectives, obstacles, traumas and insight. Every step of the reflection is illustrated with case examples, drawn from the literature. A recent development of the test concept is presented and applied to the psychotherapy of personality disorders (Sachse, 2003 [14]). Finally, the authors give brief examples of tests having occurred in their own practice as psychotherapists and discuss the models by comparing them among each other. Conclusions are drawn concerning the usefulness of the test concept for psychotherapy practice and research.

LINGO1 and LINGO2 variants are associated with essential tremor and Parkinson disease.

Genetic variation in the leucine-rich repeat and Ig domain containing 1 gene (LINGO1) was recently associated with an increased risk of developing essential tremor (ET) and Parkinson disease (PD). Herein, we performed a comprehensive study of LINGO1 and its paralog LINGO2 in ET and PD by sequencing both genes in patients (ET, n=95; PD, n=96) and by examining haplotype-tagging single-nucleotide polymorphisms (tSNPs) in a multicenter North American series of patients (ET, n=1,247; PD, n= 633) and controls (n=642). The sequencing study identified six novel coding variants in LINGO1 (p.S4C, p.V107M, p.A277T, p.R423R, p.G537A, p.D610D) and three in LINGO2 (p.D135D, p.P217P, p.V565V), however segregation analysis did not support pathogenicity. The association study employed 16 tSNPs at the LINGO1 locus and 21 at the LINGO2 locus. One variant in LINGO1 (rs9652490) displayed evidence of an association with ET (odds ratio (OR) =0.63; P=0.026) and PD (OR=0.54; P=0.016). Additionally, four other tSNPs in LINGO1 and one in LINGO2 were associated with ET and one tSNP in LINGO2 associated with PD (P<0.05). Further analysis identified one tSNP in LINGO1 and two in LINGO2 which influenced age at onset of ET and two tSNPs in LINGO1 which altered age at onset of PD (P<0.05). Our results support a role for LINGO1 and LINGO2 in determining risk for and perhaps age at onset of ET and PD. Further studies are warranted to confirm these findings and to determine the pathogenic mechanisms involved.

Anti-vascular endothelial growth factor acts on retinal microglia/macrophage activation in a rat model of ocular inflammation.

PURPOSE: To evaluate whether anti-vascular endothelial growth factor (VEGF) neutralizing antibodies injected in the vitreous of rat eyes influence retinal microglia and macrophage activation. To dissociate the effect of anti-VEGF on microglia and macrophages subsequent to its antiangiogenic effect, we chose a model of acute intraocular inflammation. METHODS: Lewis rats were challenged with systemic lipopolysaccharide (LPS) injection and concomitantly received 5 µl of rat anti-VEGF-neutralizing antibody (1.5 mg/ml) in the vitreous. Rat immunoglobulin G (IgG) isotype was used as the control. The effect of anti-VEGF was evaluated at 24 and 48 h clinically (uveitis scores), biologically (cytokine multiplex analysis in ocular media), and histologically (inflammatory cell counts on eye sections). Microglia and macrophages were immunodetected with ionized calcium-binding adaptor molecule 1 (IBA1) staining and counted based on their differential shapes (round amoeboid or ramified dendritiform) on sections and flatmounted retinas using confocal imaging and automatic quantification. Activation of microglia was also evaluated with inducible nitric oxide synthase (iNOS) and IBA1 coimmunostaining. Coimmunolocalization of VEGF receptor 1 and 2 (VEGF-R1 and R2) with IBA1 was performed on eye sections with or without anti-VEGF treatment. RESULTS: Neutralizing rat anti-VEGF antibodies significantly decreased ocular VEGF levels but did not decrease the endotoxin-induced uveitis (EIU) clinical score or the number of infiltrating cells and cytokines in ocular media (interleukin [IL]-1β, IL-6, tumor necrosis factor [TNF]-α, and monocyte chemoattractant protein [MCP]-1). Eyes treated with anti-VEGF showed a significantly decreased number of activated microglia and macrophages in the retina and the choroid and decreased iNOS-positive microglia. IBA1-positive cells expressed VEGF-R1 and R2 in the inflamed retina. CONCLUSIONS: Microglia and macrophages expressed VEGF receptors, and intravitreous anti-VEGF influenced the microglia and macrophage activation state. Taking into account that anti-VEGF drugs are repeatedly injected in the vitreous of patients with retinal diseases, part of their effects could result from unsuspected modulation of the microglia activation state. This should be further studied in other ocular pathogenic conditions and human pathology.

Molecular and clinical characterization of 25 individuals with exonic deletions of NRXN1 and comprehensive review of the literature.

This study aimed to elucidate the observed variable phenotypic expressivity associated with NRXN1 (Neurexin 1) haploinsufficiency by analyses of the largest cohort of patients with NRXN1 exonic deletions described to date and by comprehensively reviewing all comparable copy number variants in all disease cohorts that have been published in the peer reviewed literature (30 separate papers in all). Assessment of the clinical details in 25 previously undescribed individuals with NRXN1 exonic deletions demonstrated recurrent phenotypic features consisting of moderate to severe intellectual disability (91%), severe language delay (81%), autism spectrum disorder (65%), seizures (43%), and hypotonia (38%). These showed considerable overlap with previously reported NRXN1-deletion associated phenotypes in terms of both spectrum and frequency. However, we did not find evidence for an association between deletions involving the β-isoform of neurexin-1 and increased head size, as was recently published in four cases with a deletion involving the C-terminus of NRXN1. We identified additional rare copy number variants in 20% of cases. This study supports a pathogenic role for heterozygous exonic deletions of NRXN1 in neurodevelopmental disorders. The additional rare copy number variants identified may act as possible phenotypic modifiers as suggested in a recent digenic model of neurodevelopmental disorders. © 2013 Wiley Periodicals, Inc.

Multidetector CT Features of Mesenteric Vein Thrombosis.

Mesenteric vein thrombosis (MVT) accounts for 5%-15% of all mesenteric ischemic events and is classified as either primary or secondary. Primary MVT is idiopathic, whereas secondary MVT can result from a variety of underlying diseases and risk factors, including primary hypercoagulable states or prothrombotic disorders, myeloproliferative neoplasms, cancer (most frequently of the pancreas or liver), diverse inflammatory conditions, recent surgery, portal hypertension, and miscellaneous causes such as oral contraceptives or pregnancy. Clinical symptoms of MVT are rather nonspecific and are mainly characterized by abdominal pain. The mortality rate for MVT remains high, since even now the diagnosis is often delayed. Multidetector computed tomography (CT) is the modality of choice in this context. Although venous bowel ischemia occurs only infrequently with MVT, radiologists should be familiar with its multidetector CT features. Familiarity with the possible causes of MVT, the underlying pathogenic mechanisms associated with MVT, and the correlation between multidetector CT features and these pathogenic mechanisms is necessary to optimize medical management and improve patient care. © RSNA, 2012.