The dmf1/mid1 gene is essential for correct positioning of the division septum in fission yeast.

Little is known about the mechanisms that establish the position of the division plane in eukaryotic cells. Wild-type fission yeast cells divide by forming a septum in the middle of the cell at the end of mitosis. Dmf1 mutants complete mitosis and initiate septum formation, but the septa that form are positioned at random locations and angles in the cell, rather than in the middle. We have cloned the dmf1 gene as a suppressor of the cdc7-24 mutant. The dmf1 mutant is allelic with mid1. The gene encodes a novel protein containing a putative nuclear localization signal, and a carboxy-terminal PH domain. In wild-type cells, Dmf1p is nuclear during interphase, and relocates to form a medial ring at the cell cortex coincident with the onset of mitosis. This relocalization occurs before formation of the actin ring and is associated with increased phosphorylation of Dmf1p. The Dmf1p ring can be formed in the absence of an actin ring, but depends on some of the genes required for actin ring formation. When the septum is completed and the cells separate, Dmf1p staining is once again nuclear. These data implicate Dmf1p as an important element in assuring correct placement of the division septum in Schizosaccharomyces pombe cells.

Tumor-host interactions Part 1: Stromal signatures of breast and prostate cancer Part 2: GLG1 and the control of the secretory pathway in tumor cells

Tumor-host interaction is a key determinant during cancer progression, from primary tumor growth to metastatic dissemination. At each step, tumor cells have to adapt to and subvert different types of microenvironment, leading to major phenotypic and genotypic alterations that affect both tumor and surrounding stromal compartments. Understanding the molecular mechanisms that govern tumor-host interplay may be essential for better comprehension of tumorigenesis in an effort to improve current anti-cancer therapies. The present work is composed of two projects that address tumor-host interactions from two different perspectives, the first focusing on the characterization of tumor-associated stroma and the second on membrane trafficking in tumor cells. Part 1. To selectively address stromal gene expression changes during cancer progression, oligonucleotide-based Affymetrix microarray technology was used to analyze the transcriptomes of laser-microdissected stromal cells derived from invasive human breast and prostate carcinoma. Comparison showed that invasive breast and prostate cancer elicit distinct, tumor-specific stromal responses, with a limited panel of shared induced and/or repressed genes. Both breast and prostate tumor-specific deregulated stromal gene sets displayed statistically significant survival-predictive ability for their respective tumor type. By contrast, a stromal gene signature common to both tumor types did not display prognostic value, although expression of two individual genes within this common signature was found to be associated with patient survival. Part 2. GLG1 is known as an E-selectin ligand and an intracellular FGF receptor, depending on cell type and context. Immunohistochemical and immunofluorescence analyses showed that GLG1 is primarily localized in the Golgi of human tumor cells, a central location in the biosynthetic/secretory pathways. GLG1 has been shown to interact with and to recruit the ARF GEF BIGI to the Golgi membrane. Depletion of GLG1 or BIGI markedly reduced ARF3 membrane localization and activation, and altered the Golgi structure. Interestingly, these perturbations did not impair constitutive secretion in general, but rather seemed to impair secretion of a specific subset of proteins that includes MMP-9. Thus, GLG1 coordinates ARF3 activation by recruiting BIGI to the Golgi membrane, thereby affecting secretion of specific molecules. - Les interactions tumeur-hôte constituent un élément essentiel à la progression tumorale, de la croissance de la tumeur primaire à la dissémination des métastases. A chaque étape, les cellules tumorales doivent s'adapter à différents types de microenvironnement et les détourner à leur propre avantage, donnant lieu à des altérations phénotypiques et génotypiques majeures qui affectent aussi bien la tumeur elle-même que le compartiment stromal environnant. L'étude des mécanismes moléculaires qui régissent les interactions tumeur-hôte constitue une étape essentielle pour une meilleure compréhension du processus de tumorigenèse dans le but d'améliorer les thérapies anti cancer existantes. Le travail présenté ici est composé de deux projets qui abordent la problématique des interactions tumeur-hôte selon différentes perspectives, le premier se concentrant sur la caractérisation du stroma tumoral et le second sur le trafic intracellulaire des cellules tumorales. Partie 1. Pour examiner les changements d'expression des gènes dans le stroma en réponse à la progression du cancer, des puces à ADN Affymetrix ont été utilisées afin d'analyser les transcriptomes des cellules stromales issues de carcinomes invasifs du sein et de la prostate et collectées par microdissection au laser. L'analyse comparative a montré que les cancers invasifs du sein et de la prostate provoquent des réponses stromales spécifiques à chaque type de tumeur, et présentent peu de gènes induits ou réprimés de façon similaire. L'ensemble des gènes dérégulés dans le stroma associé au cancer du sein, ou à celui de la prostate, présente une valeur pronostique pour les patients atteints d'un cancer du sein, respectivement de la prostate. En revanche, la signature stromale commune aux deux types de cancer n'a aucune valeur prédictive, malgré le fait que l'expression de deux gènes présents dans cette liste soit liée à la survie des patients. Partie 2. GLG1 est connu comme un ligand des sélectines E ainsi que comme récepteur intracellulaire pour des facteurs de croissances FGFs selon le type de cellule dans lequel il est exprimé. Des analyses immunohistochimiques et d'immunofluorescence ont montré que dans les cellules tumorales, GLG1 est principalement localisé au niveau de l'appareil de Golgi, une place centrale dans la voie biosynthétique et sécrétoire. Nous avons montré que GLG1 interagit avec la protéine BIGI et participe à son recrutement à la membrane du Golgi. L'absence de GLG1 ou de BIGI réduit drastiquement le pool d'ARF3 associé aux membranes ainsi que la quantité d'ARF3 activés, et modifie la structure de l'appareil de Golgi. Il est particulièrement intéressant de constater que ces perturbations n'ont pas d'effet sur la sécrétion constitutive en général, mais semblent plutôt affecter la sécrétion spécifique d'un sous-groupe défini de protéines comprenant MMP-9. GLG1 coordonne donc l'activation de ARF3 en recrutant BIGI à la membrane du Golgi, agissant par ce moyen sur la sécrétion de molécules spécifiques.

Who drinks most of the total alcohol in young men--risky single occasion drinking as normative behaviour.

AIMS: The objectives of this study were to analyse (a) the distribution of risky single-occasion drinking (RSOD) among 19-year-old men in Switzerland and (b) to show the percentage of all alcohol consumption in the form of RSOD. METHODS: The study was based on a census of Swiss francophone 19-year-old men consecutively reporting for processing. The study was conducted at Army Recruitment Center. The participants were 4116 recruits consecutively enrolling for mandatory army recruitment procedures between 23 January and 29 August in 2007. The measures were alcohol consumption measured in drinks of approximately 10 g of pure alcohol, number of drinking occasions with six or more drinks (RSOD) in the past 12 months and a retrospective 1 week drinking diary. RESULTS: 264 recruits were never seen by the research staff, 3536 of the remaining 3852 conscripts completed a questionnaire which showed that 7.2% abstained from alcohol and 75.5% of those drinking had an RSOD day at least monthly. The typical frequency of drinking was 1-3 days per week on weekends. The average quantity on weekends was about seven drinks, 69.3% of the total weekly consumption was in the form of RSOD days, and of all the alcohol consumed, 96.2% was by drinkers who had RSOD days at least once a month. CONCLUSION: Among young men, RSOD constitutes the norm. Prevention consequently must address the total population and not only high-risk drinkers.

High prevalence of the metabolic syndrome in HIV-infected patients: impact of different definitions of the metabolic syndrome.

INTRODUCTION: This study describes the characteristics of the metabolic syndrome in HIV-positive patients in the Data Collection on Adverse Events of Anti-HIV Drugs study and discusses the impact of different methodological approaches on estimates of the prevalence of metabolic syndrome over time. METHODS: We described the prevalence of the metabolic syndrome in patients under follow-up at the end of six calendar periods from 2000 to 2007. The definition that was used for the metabolic syndrome was modified to take account of the use of lipid-lowering and antihypertensive medication, measurement variability and missing values, and assessed the impact of these modifications on the estimated prevalence. RESULTS: For all definitions considered, there was an increasing prevalence of the metabolic syndrome over time, although the prevalence estimates themselves varied widely. Using our primary definition, we found an increase in prevalence from 19.4% in 2000/2001 to 41.6% in 2006/2007. Modification of the definition to incorporate antihypertensive and lipid-lowering medication had relatively little impact on the prevalence estimates, as did modification to allow for missing data. In contrast, modification to allow the metabolic syndrome to be reversible and to allow for measurement variability lowered prevalence estimates substantially. DISCUSSION: The prevalence of the metabolic syndrome in cohort studies is largely based on the use of nonstandardized measurements as they are captured in daily clinical care. As a result, bias is easily introduced, particularly when measurements are both highly variable and may be missing. We suggest that the prevalence of the metabolic syndrome in cohort studies should be based on two consecutive measurements of the laboratory components in the syndrome definition.

The ArgR regulatory protein, a helper to the anaerobic regulator ANR during transcriptional activation of the arcD promoter in Pseudomonas aeruginosa.

Pseudomonas aeruginosa, when deprived of oxygen, generates ATP from arginine catabolism by enzymes of the arginine deiminase pathway, encoded by the arcDABC operon. Under conditions of low oxygen tension, the transcriptional activator ANR binds to a site centered 41.5 bp upstream of the arcD transcriptional start. ANR-mediated anaerobic induction was enhanced two- to threefold by extracellular arginine. This arginine effect depended, in trans, on the transcriptional regulator ArgR and, in cis, on an ArgR binding site centered at -73.5 bp in the arcD promoter. Binding of purified ArgR protein to this site was demonstrated by electrophoretic mobility shift assays and DNase I footprinting. This ArgR recognition site contained a sequence, 5'-TGACGC-3', which deviated in only 1 base from the common sequence motif 5'-TGTCGC-3' found in other ArgR binding sites of P. aeruginosa. Furthermore, an alignment of all known ArgR binding sites confirmed that they consist of two directly repeated half-sites. In the absence of ANR, arginine did not induce the arc operon, suggesting that ArgR alone does not activate the arcD promoter. According to a model proposed, ArgR makes physical contact with ANR and thereby facilitates initiation of arc transcription.

La diminution de l'activité du répresseur ICER dans les adipocytes est responsable de la résistance à l'insuline dirigée par le facteur CREB dans l'obésité [The decreased activity of the repressor ICER in adipocytes is responsible for insulin resistance led by factor CREB in obesity.]

Introduction: Une élévation de l'activité des facteurs de transcription CREBs dans le tissu adipeux est en partie responsable de l'insulino-résistance systémique dans l'obésité. Le facteur «Inducible cAMP early repressor» (ICER) est un répresseur transcriptionnel passif dont le niveau d'expression antagonise l'activité des CREBs. L'objectif de ce travail adipocytaire des CREBs dans l'obésité chez l'Homme et la souris. Matériels et méthodes: Du tissu adipeux blanc (TAB) a été prélevé chez des souris obèses nourries sous une diète normale et des souris obèses nourries sous un régime riche en graisses pendant 12 semaines. Des biopsies de tissu adipeux viscéral (TAV) ont été prélevées chez les sujets humains minces (BMI = 24 ± 0,5 kg/m2) et obèses (BMI > 35 kg/m2). L'expression des gènes est quantifiée par RT-PCR quantitative. L'activité des CREBs et d'ICER est mesurée par des expériences de retard sur gel. L'activité des histones déacétylases est quantifiée par dosage colorimétrique. Résultats: L'expression et l'activité d'ICER sont diminuées dans le TAB des souris obèses, hyper-glycémiques et insulino-résistantes. De même, l'activité d'ICER est réduite dans le TAV des sujets humains obèses. Cette réduction corrèle avec une augmentation de l'activité des CREBs, une réduction de l'expression de Glut4 et de l'adiponectine, à la fois chez l'Homme et la souris. La diminution de l'expression d'ICER n'est observée que dans la fraction adipocytaire du tissu adipeux. L'expression d'ICER est contrôlée par l'activité des HDACs. L'inhibition des HDACs inhibe l'expression d'ICER dans les adipocytes. L'activité totale des HDACs est réduite dans les tissus adipeux chez les souris et chez les sujets humains obèses. Conclusion: La diminution de l'activité d'ICER dans les adipocytes par une modification de l'activité des HDACs serait responsable de l'augmentation de l'activité des CREBs dans l'obésité.

Analyse critique des résultats de biopsies musculaires et de la méthodologie utilisée dans 889 cas d'affections neuromusculaires [Critical analysis of the results of muscle biopsies and of the methods used in 889 cases of neuromuscular disorders]

The contribution of muscle biopsies to the diagnosis of neuromuscular disorders and the indications of various methods of examination are investigated by analysis of 889 biopsies from patients suffering from myopathic and/or neurogenic disorders. Histo-enzymatic studies performed on frozen material as well as immunohistochemistry and electron microscopy allowed to provide specific diagnoses in all the neurogenic disorders (polyneuropathies and motor neuron diseases), whereas one third of myopathies remained uncertain. Confrontation of neuropathological data with the clinical indications for histological investigations shows that muscle biopsies reveal the diagnosis in 25% of the cases (mainly in congenital and metabolic myopathies) and confirm and/or complete the clinical diagnosis in 50%. In the remaining cases with non specific abnormalities neuropathological investigations may help the clinician by excluding well defined neuromuscular disorders. Analysis of performed studies and results of investigations show the contribution and specificity of each method for the diagnosis. Statistical evaluation of this series indicates that cryostat sectioning for histo- and immunochemical and electron microscopy increases the rate of diagnoses of neuromuscular diseases: full investigation was necessary for the diagnosis in 30% of the cases. The interpretation of the wide range of pathological reactions in muscles requires a close cooperation with the clinician.

The presence of conifer resin decreases the use of the immune system in wood ants

1. Wood ants (Formica paralugubris) incorporate large amounts of solidified conifer resin into their nest, which reduces the density of many bacteria and fungi and protects the ants against some detrimental micro-organisms. By inducing an environment unfavourable to pathogens, the presence of resin may allow workers to reduce the use of their immune system. 2. The present study tested the hypothesis that the presence of resin decreases the immune activity of wood ants. Specifically, three components of the humoral immune defences of workers kept in resin-rich and resin-free experimental nests (antibacterial, lytic, and prophenoloxidase activities) were compared. 3. The presence of resin was associated with reduced bacterial and fungal densities in nest material and with a small decrease in worker antibacterial and lytic activities. The prophenoloxidase activity was very low in all workers and was not affected by the presence of resin. 4. These results suggest that collective medication with resin reduces pathogen pressure, which in turn decreases the use of the inducible part of the immune system. More generally, the use of plant secondary compounds might be an efficient and economical way to fight pathogens.

Ultrastructural, morphometrical and immunocytochemical analyses of the exocrine pancreas in a hibernating dormouse.

Pancreatic acinar cells of euthermic, hibernating and arousing individuals of the hazel dormouse Muscardinus avellanarius (Gliridae) have been observed at the electron-microscopic level and analysed by means of ultrastructural morphometry and immunocytochemistry in order to investigate possible fine structural changes of cellular components during periods of strikingly different degrees of metabolic activity. During hibernation, the cisternae of the rough endoplasmic reticulum (RER) flatten assuming a parallel pattern, the Golgi apparatus is extremely reduced and the mitochondria contain many electron-dense particles. The cell nuclei appear irregularly shaped, with deep indentations containing small zymogen granules. They also contain abundant coiled bodies and unusual constituents, such as amorphous bodies and dense granular bodies. Large numbers of zymogen granules occur in all animals. However, the acinar lumina are open and filled with zymogen only in euthermic animals, whereas, in hibernating and arousing individuals, they appear to be closed. Morphometrical analyses indicate that, in pancreatic acinar cells, nuclei and zymogen granules significantly decrease in size from euthermia to hibernation, probably reflecting a drastic decrease of metabolic activities, mainly protein synthesis and processing. In all the studied animals, immunocytochemistry with specific antibodies has revealed an increasing gradient in alpha-amylase content along the RER-Golgi-zymogen granule pathway, reflecting the protein concentration along the secretory pathway. Moreover, during deep hibernation, significantly larger amounts of alpha-amylase accumulate in RER and zymogen granules in comparison to the other seasonal phases analysed. Upon arousal, all cytoplasmic and nuclear constituents restore their euthermic aspect and all morphometrical and immunocytochemical parameters exhibit the euthermic values, thereby indicating a rapid resumption of metabolic activities.

Place du frottis cytologique à l'adolescence [Role of the PAP smear in adolescence]

The publication of the 2006 directives concerning the management of PAP smears has incited us to update our internal protocols at the CHUV, which are described in this article. A new addition to these directives is the specific management of adolescent PAP smears, who present both a high HPV carriage rate and increased incidence of cytological abnormalities with a favorable outcome in most cases. Our goal is to avoid over-treating dysplasias in this type of patient in order to avoid long-term complications. Emphasis is placed on the first gynecological consultation where a listening ear and clear and targeted information remain essential in the proper management of a young patient.

Activation of the NLRP3 inflammasome in dendritic cells induces IL-1beta-dependent adaptive immunity against tumors.

The therapeutic efficacy of anticancer chemotherapies may depend on dendritic cells (DCs), which present antigens from dying cancer cells to prime tumor-specific interferon-gamma (IFN-gamma)-producing T lymphocytes. Here we show that dying tumor cells release ATP, which then acts on P2X(7) purinergic receptors from DCs and triggers the NOD-like receptor family, pyrin domain containing-3 protein (NLRP3)-dependent caspase-1 activation complex ('inflammasome'), allowing for the secretion of interleukin-1beta (IL-1beta). The priming of IFN-gamma-producing CD8+ T cells by dying tumor cells fails in the absence of a functional IL-1 receptor 1 and in Nlpr3-deficient (Nlrp3(-/-)) or caspase-1-deficient (Casp-1(-/-)) mice unless exogenous IL-1beta is provided. Accordingly, anticancer chemotherapy turned out to be inefficient against tumors established in purinergic receptor P2rx7(-/-) or Nlrp3(-/-) or Casp1(-/-) hosts. Anthracycline-treated individuals with breast cancer carrying a loss-of-function allele of P2RX7 developed metastatic disease more rapidly than individuals bearing the normal allele. These results indicate that the NLRP3 inflammasome links the innate and adaptive immune responses against dying tumor cells.

Evaluation of the inhalation technique in asthmatic children visiting a specialised outpatient clinic

Background and objective: Asthma is one of the most frequent chronic diseases affecting children and adolescents. Good compliance is indispensable for effective treatment since a suboptimal use of inhalation devices can result in decreased therapeutic efficacy and increased morbidity. The objective of this work was to evaluate the inhalation technique of paediatric patients visiting a specialized consultation clinic of a university hospital. Design: Observational prospective study during a 3-month period. Setting Specialized consultation clinic of a university hospital. Main outcome measures: This study involved 40 outpatient infants, children and adolescents visiting alone or with their parent(s). Patients' data (age, sex, weight, diagnostic, reason for consulting, previous consultations) and their medicines were compiled using an ad hoc form. Filmed sequences of the inhalation procedure used by each child were reviewed independently by members of an interdisciplinary team consisting in a physician, a pharmacist, a nurse and a physiotherapist. A score of 1 was assigned to each correct step in the procedure, and a score of 0 to an incorrect step. A perfect procedure implied 12 correct steps. Results: Thirty patients were treated with a metered-dose inhaler and an inhalation chamber (Babyhaler or AeroChamber Plus); ten other patients were treated with a dry powder inhaler (Diskus or Turbuhaler). The agreement between the members of the interdisciplinary team was considered satisfactory. Nine patients (22.5%) reached an average score lower than 7, 18 patients (45%) a score between 7 and 10 and 13 (32.5%) a score equal to or better than 10. No patient reached the maximum score of 12. Users of the metered-dose inhalers (average score = 9.2) showed a better technique than users of the dry powder inhalers (average score = 7.4). Disappointingly, the score was not improved during a second consultation or following regular consultations. Conclusions: Video recording is a simple method to evaluate the degree of mastery of an inhalation procedure in paediatric patients. The method allows a convenient and efficient identification of suboptimal procedure steps by the hospital staff, and opens the way to patient-specific teaching. In two-thirds of juvenile patients, their inhalation technique was suboptimal despite initial training. This study shows conclusively that the inhalation technique in paediatric patients must be monitored during each examination, and teaching measures taken to improve it when necessary.