Infections and functional impairment in nursing home residents: a reciprocal relationship.

OBJECTIVES: To determine the relationship between infections and functional impairment in nursing home residents. DESIGN: Prospective cohort study (follow-up period, 6 months). SETTING: Thirty-nine nursing homes in western Switzerland. PARTICIPANTS: A total of 1,324 residents aged 65 and older (mean age 85.7; 76.6% female) who agreed to participate, or their proxies, by oral informed consent. MEASUREMENTS: Functional status measured every 3 months. Two different outcomes were used: (a) functional decline defined as death or decreased function at follow-up and (b) functional status score using a standardized measure. RESULTS: At the end of follow-up, mortality was 14.6%, not different for those with and without infection (16.2% vs 13.1%, P=.11). During both 3-month periods, subjects with infection had higher odds of functional decline, even after adjustment for baseline characteristics and occurrence of a new illness (adjusted odds ratio (AOR)=1.6, 95% confidence interval (CI)=1.2-2.2, P=.002, and AOR=1.5, 95% CI=1.1-2.0, P=.008, respectively). The odds of decline increased in a stepwise fashion in patients with zero, one, and two or more infections. The analyses predicting functional status score (restricted to subjects who survived) gave similar results. A survival analysis predicting time to first infection confirmed a stepwise greater likelihood of infection in subjects with moderate and severe impairment at baseline than in subjects with no or mild functional impairment at baseline. CONCLUSION: Infections appear to be both a cause and a consequence of functional impairment in nursing home residents. Further studies should be undertaken to investigate whether effective infection control programs can also contribute to preventing functional decline, an important component of these residents' quality of life.

Population pharmacokinetic modelling and evaluation of different dosage regimens for darunavir and ritonavir in HIV-infected individuals.

OBJECTIVES: Darunavir is a protease inhibitor that is administered with low-dose ritonavir to enhance its bioavailability. It is prescribed at standard dosage regimens of 600/100 mg twice daily in treatment-experienced patients and 800/100 mg once daily in naive patients. A population pharmacokinetic approach was used to characterize the pharmacokinetics of both drugs and their interaction in a cohort of unselected patients and to compare darunavir exposure expected under alternative dosage regimens. METHODS: The study population included 105 HIV-infected individuals who provided darunavir and ritonavir plasma concentrations. Firstly, a population pharmacokinetic analysis for darunavir and ritonavir was conducted, with inclusion of patients' demographic, clinical and genetic characteristics as potential covariates (NONMEM(®)). Then, the interaction between darunavir and ritonavir was studied while incorporating levels of both drugs into different inhibitory models. Finally, model-based simulations were performed to compare trough concentrations (Cmin) between the recommended dosage regimen and alternative combinations of darunavir and ritonavir. RESULTS: A one-compartment model with first-order absorption adequately characterized darunavir and ritonavir pharmacokinetics. The between-subject variability in both compounds was important [coefficient of variation (CV%) 34% and 47% for darunavir and ritonavir clearance, respectively]. Lopinavir and ritonavir exposure (AUC) affected darunavir clearance, while body weight and darunavir AUC influenced ritonavir elimination. None of the tested genetic variants showed any influence on darunavir or ritonavir pharmacokinetics. The simulations predicted darunavir Cmin much higher than the IC50 thresholds for wild-type and protease inhibitor-resistant HIV-1 strains (55 and 550 ng/mL, respectively) under standard dosing in >98% of experienced and naive patients. Alternative regimens of darunavir/ritonavir 1200/100 or 1200/200 mg once daily also had predicted adequate Cmin (>550 ng/mL) in 84% and 93% of patients, respectively. Reduction of darunavir/ritonavir dosage to 600/50 mg twice daily led to a 23% reduction in average Cmin, still with only 3.8% of patients having concentrations below the IC50 for resistant strains. CONCLUSIONS: The important variability in darunavir and ritonavir pharmacokinetics is poorly explained by clinical covariates and genetic influences. In experienced patients, treatment simplification strategies guided by drug level measurements and adherence monitoring could be proposed.

Use of active personal dosemeters in interventional radiology and cardiology: Tests in hospitals - ORAMED project

Although active personal dosemeters (APDs) are not used quite often in hospital environments, the possibility to assess the dose and/or dose rate in real time is particularly interesting in interventional radiology and cardiology (IR/IC) since operators can receive relatively high doses while standing close to the primary radiation field.A study concerning the optimization of the use of APDs in IR/IC was performed in the framework of the ORAMED project, a Collaborative Project (2008-2011) supported by the European Commission within its 7th Framework Program. This paper reports on tests performed with APDs on phantoms using an X-ray facility in a hospital environment and APDs worn by interventionalists during routine practice in different European hospitals.The behaviour of the APDs is more satisfactory in hospitals than in laboratories with respect to the influence of the tube peak high voltage and pulse width, because the APDs are tested in scattered fields with dose equivalent rates generally lower than 1 Sv.h(-1).

The roles of PKCδ and Src kinases in the glucocorticoid induction and the TGF-β superinduction of the mouse mammary tumor virus transcription in B lymphocytes

Résumé : Le virus tumoral de la glande mammaire de la souris (MMTV) est un rétrovirus provoquant le développement de tumeurs dans les glandes mammaires des souris susceptibles femelles. Au cours de son évolution, le virus s'est adapté et s'exprime dans des cellules spécialisées. Les lymphocytes B sont les premières cellules infectées et elles sont essentielles pour la propagation de l'infection aux glandes mammaires. Dans notre étude, le virus MMTV a été utilisé afin d'examiner les voies de signalisation induites par les glucocorticoïdes (dexaméthasone (dex), une hormone stéroïdienne) et le transforming growth factor-f3 (TGF-P, une cytokine), deux molécules impliquées dans l'activation de la transcription à partir du promoteur du MMTV dans les cellules B. Le TGF-P seul n'influence pas l'activité du promoteur du MMTV. Par contre, en synergie avec dex, le TGF-P provoque une super-induction de l'expression du promoteur par rapport à une stimulation par le glucocorticoïde seul. Cette super-induction est régulée par une famille de protéines, les Smads. Ainsi, dans les lymphocytes B, l'utilisation du MMTV a permis de mettre en évidence une nouvelle synergie entre les glueocortieoïdes et le TGF-p. pans ce travail, l'utilisation d'inhibiteurs pharmacologiques et de mutants « dominant-négatifs » nous a pet mis de démontrer qu'une Protéine Kinase C delta (PKC5) active est impliquée dans la transduction du signal lors de la réponse au dex ainsi que celle au TGF-P. Néanmoins, la PKC5 est régulée différemment dans chaque voie spécifique : la voie du TGF-p nécessitait l'activation du PKC5 par diacylglycerol (DAG) et la phosphorylation de tyrosines spécifiques, alors que la voie impliquant les glucocorticoïdes ne le nécessitait pas. Nous avons aussi démontré qu'une tyrosine kinase de la famille Src est responsable de la phosphorylation des tyrosines sur la PKC5. Les essais de kinase in vitro nous ont permis de découvrir que plusieurs Src kinases peuvent phosphoryler la PKC6 dans les cellules B et qu'elles étaient constitutivement actives. Enfin, nous avons montré qu'il existe une interaction protéine - protéine induite par dex, entre le récepteur aux glucocorticoïdes (GR) et la PKC5 dans les cellules B, une association qui n'a pas été démontrée auparavant. Par ailleurs, nous avons analysé les domaines d'interactions entre PKC5 et GR en utilisant les essais de «GST pull-down». Nos résultats montrent que le domaine régulateur de la PKC5 et celui qui interagit avec l'ADN du GR sont impliqués. En résumé, nous avons trouvé que dans une lignée lymphocytaire B, le virus MMTV utilise des mécanismes pour réguler à la fois la transcription et la voie de signalisation qui sont différents de ceux utilisés dans les cellules mammaires épithéliales et les fibroblastes. Nos découvertes pourraient être utilisées comme modèles pour l'étude de gènes cellulaires impliqués dans des processus tels qu'inflammation, immunité ou cancérogénèse. Summary: Mouse Mammary Tumor Virus (MMTV) is a retrovirus that causes tumors in the mammary glands of susceptible female mice and has adapted evolutionarily to be expressed in specialized cells. The B lymphocytes are the first cells to be infected by the MMTV and are essential for the spread of infection to the mammary glands. Here, we used the MMTV as a model system to investigate the signalling cascade induced by giucocorticoids (dexamethasone, "dex", a steroid hormone), and by Transforming Growth Factor-beta (TGF-P, a cytokine) leading to its transcriptional activation in B lymphocytes. By itself, TGF-I3 does not affect the basal activity of the MMTV promoter. However, TGF-13 significantly increases glucocorticoid-induced expression, through its effectors, the Smad factors. Thus, MMTV in B cells demonstrates a novel synergism between glucocorticoids and TGF-16. In this thesis project, we present evidence, based on the use of pharmacological inhibitors and of dominant-negative mutants, that an active Protein Kinase C delta (PKC6) is required as a signal transducer for the dex response and for the TGF-P superinduction as well. The PKC6 is differentially regulated in each specific pathway: whereas the TGF-13 superinduction required PKC6 to be activated by diacylglycerol (DAG) and to be phosphorylated at specific tyrosine residues, the glueocorticoid-induced pathway did not. We also showed that a protein tyrosine kinase of the Src family is responsible for the phosphorylation of tyrosines on PKC6. By performing in vitro kinase assays, we found that several Src kinases of B cells were able to phosphorylate PKC6 and that they were constitutively active. Finally, we demonstrate a dex-dependent functional protein-protein interaction between the glucocorticoid receptor (GR) and PKC6 in B cells, an association that has not been previously described. We further analysed the interacting domains of PKG6 and GR using in vitro GST pull-down assays, whereby the regulatory domain of PKC6 and the extended DNA-binding domain of the GR were involved. In summary, we found that in B-lymphoid cell lines, MMTV uses novel mechanisms of transcriptional control and signal transduction that are different from those at work in mammary epithelial or fibroblastic cells. These findings will be used as model for cellular genes involved in cellular processes such as immune functions, inflammation, or oncogenic transformation that may have a similar pattern of regulation.

Combining palaeodistribution modelling and phylogeographical approaches for identifying glacial refugia in Alpine Primula

Aim We investigated the late Quaternary history of two closely related and partly sympatric species of Primula from the south-western European Alps, P. latifolia Lapeyr. and P. marginata Curtis, by combining phylogeographical and palaeodistribution modelling approaches. In particular, we were interested in whether the two approaches were congruent and identified the same glacial refugia. Location South-western European Alps. Methods For the phylogeographical analysis we included 353 individuals from 28 populations of P. marginata and 172 individuals from 15 populations of P. latifolia and used amplified fragment length polymorphisms (AFLPs). For palaeodistribution modelling, species distribution models (SDMs) were based on extant species occurrences and then projected to climate models (CCSM, MIROC) of the Last Glacial Maximum (LGM), approximately 21 ka. Results The locations of the modelled LGM refugia were confirmed by various indices of genetic variation. The refugia of the two species were largely geographically isolated, overlapping only 6% to 11% of the species' total LGM distribution. This overlap decreased when the position of the glacial ice sheet and the differential elevational and edaphic distributions of the two species were considered. Main conclusions The combination of phylogeography and palaeodistribution modelling proved useful in locating putative glacial refugia of two alpine species of Primula. The phylogeographical data allowed us to identify those parts of the modelled LGM refugial area that were likely source areas for recolonization. The use of SDMs predicted LGM refugial areas substantially larger and geographically more divergent than could have been predicted by phylogeographical data alone

Le poids, les habitudes alimentaires et l'activité physique dans la population en Suisse: le projet MONICA. [Weight, nutritional habits and physical-activity in Switzerland: the MONICA-Project].

La première enquête de prévalence des facteurs de risque pour les maladies cardio-vasculaires qui a été effectuée auprès de la population des cantons de Vaud, Fribourg et du Tessin, dans le cadre du Projet MONICA, a permis de décrire la distribution de l'indice de masse corporelle. Entre 25 et 74 ans, près d'une personne sur 4 a un excès de poids préjudiciable à sa santé, cette proportion étant même de plus de 1 sur 3 chez les hommes tessinois. Cet état de fait n'est peut-être pas irrémédiable puisque 1 femme sur 3 et 1 homme sur 5 a modifié ses habitudes alimentaires dans le sens d'une nourriture plus saine et moins énergétique au cours des 12 mois précédant l'enquête. Cependant une activité physique régulière, susceptible d'avoir un rôle préventif sur la survenue des maladies cardio-vasculaires et qui pourrait contribuer à la diminution de la fréquence de l'obésité, n'est exercée que par moins de la moitié de la population en moyenne. C'est probablement l'exercice régulier d'activités sportives qui permettrait le plus d'augmenter le niveau général de l'activité physique dans la population puisque peu de personnes exercent une profession exigeant d'intenses efforts physiques.

Use of a combined ex vivo/in vivo population approach for screening of human genes involved in the human immunodeficiency virus type 1 life cycle for variants influencing disease progression.

Humans differ substantially with respect to susceptibility to human immunodeficiency virus type 1 (HIV-1). We evaluated variants of nine host genes participating in the viral life cycle for their role in modulating HIV-1 infection. Alleles were assessed ex vivo for their impact on viral replication in purified CD4 T cells from healthy blood donors (n = 128). Thereafter, candidate alleles were assessed in vivo in a cohort of HIV-1-infected individuals (n = 851) not receiving potent antiretroviral therapy. As a benchmark test, we tested 12 previously reported host genetic variants influencing HIV-1 infection as well as single nucleotide polymorphisms in the nine candidate genes. This led to the proposition of three alleles of PML, TSG101, and PPIA as potentially associated with differences in progression of HIV-1 disease. In a model considering the combined effects of new and previously reported gene variants, we estimated that their effect might be responsible for lengthening or shortening by up to 2.8 years the period from 500 CD4 T cells/mul to <200 CD4 T cells/mul.

Establishment of models to study mouse and human retinogenesis "in vitro" : isolation and characterization of retinal stem cells

SUMMARY IN FRENCH Les cellules souches sont des cellules indifférenciées capables a) de proliférer, b) de s'auto¬renouveller, c) de produire des cellules différenciées, postmitotiques et fonctionnelles (multipotencialité), et d) de régénérer le tissu après des lésions. Par exemple, les cellules de souches hematopoiétiques, situées dans la moelle osseuse, peuvent s'amplifier, se diviser et produire diverses cellules différenciées au cours de la vie, les cellules souches restant dans la moelle osseuse et consentant leur propriété. Les cellules souches intestinales, situées dans la crypte des microvillosités peuvent également régénérer tout l'intestin au cours de la vie. La rétine se compose de six classes de neurones et d'un type de cellule gliale. Tous ces types de cellules sont produits par un progéniteur rétinien. Le pic de production des photorécepteurs se situe autour des premiers jours postnatals chez la souris. A cette période la rétine contient les cellules hautement prolifératives. Dans cette étude, nous avons voulu analyser le phénotype de ces cellules et leur potentiel en tant que cellules souches ou progénitrices. Nous nous sommes également concentrés sur l'effet de certains facteurs épigéniques sur leur destin cellulaire. Nous avons observé que toutes les cellules prolifératives isolées à partir de neurorétines postnatales de souris expriment le marqueur de glie radiaire RC2, ainsi que des facteurs de transcription habituellement trouvés dans la glie radiaire (Mash1, Pax6), et répondent aux critères des cellules souches : une capacité élevée d'expansion, un état indifférencié, la multipotencialité (démontrée par analyse clonale). Nous avons étudié la différentiation des cellules dans différents milieux de culture. En l'absence de sérum, l'EGF induit l'expression de la β-tubulin-III, un marqueur neuronal, et l'acquisition d'une morphologie neuronale, ceci dans 15% des cellules présentes. Nous avons également analysé la prolifération de cellules. Seulement 20% des cellules incorporent le bromodéoxyuridine (BrdU) qui est un marqueur de division cellulaire. Ceci démontre que l'EGF induit la formation des neurones sans une progression massive du cycle cellulaire. Par ailleurs, une stimulation de 2h d'EGF est suffisante pour induire la différentiation neuronale. Certains des neurones formés sont des cellules ganglionnaires rétiniennes (GR), comme l'indique l'expression de marqueurs de cellules ganglionnaires (Ath5, Brn3b et mélanopsine), et dans de rare cas d'autres neurones rétiniens ont été observés (photorécepteurs (PR) et cellules bipolaires). Nous avons confirmé que les cellules souches rétiniennes tardives n'étaient pas restreintes au cours du temps et qu'elles conservent leur multipotencialité en étant capables de générer des neurones dits précoces (GR) ou tardifs (PR). Nos résultats prouvent que l'EGF est non seulement un facteur contrôlant le développement glial, comme précédemment démontré, mais également un facteur efficace de différentiation pour les neurones rétiniens, du moins in vitro. D'autre part, nous avons voulu établir si l'oeil adulte humain contient des cellules souches rétiniennes (CSRs). L'oeil de certains poissons ou amphibiens continue de croître pendant l'âge adulte du fait de l'activité persistante des cellules souches rétiniennes. Chez les poissons, le CSRs se situe dans la marge ciliaire (CM) à la périphérie de la rétine. Bien que l'oeil des mammifères ne se développe plus pendant la vie d'adulte, plusieurs groupes ont prouvé que l'oeil de mammifères adultes contient des cellules souches rétiniennes également dans la marge ciliaire plus précisément dans l'épithélium pigmenté et non dans la neurorétine. Ces CSRs répondent à certains critères des cellules souches. Nous avons identifié et caractérisé les cellules souches rétiniennes résidant dans l'oeil adulte humain. Nous avons prouvé qu'elles partagent les mêmes propriétés que leurs homologues chez les rongeurs c.-à-d. auto-renouvellement, amplification, et différenciation en neurones rétiniens in vitro et in vivo (démontré par immunocoloration et microarray). D'autre part, ces cellules peuvent être considérablement amplifiées, tout en conservant leur potentiel de cellules souches, comme indiqué par l'analyse de leur profil d'expression génique (microarray). Elles expriment également des gènes communs à diverses cellules souches: nucleostemin, nestin, Brni1, Notch2, ABCG2, c-kit et son ligand, aussi bien que cyclin D3 qui agit en aval de c-kit. Nous avons pu montré que Bmi1et Oct4 sont nécessaires pour la prolifération des CSRs confortant leur propriété de cellules souches. Nos données indiquent que la neurorétine postnatale chez la souris et l'épithélium pigmenté de la marge ciliaire chez l'humain adulte contiennent les cellules souches rétiniennes. En outre, nous avons développé un système qui permet d'amplifier et de cultiver facilement les CSRs. Ce modèle permet de disséquer les mécanismes impliqués lors de la retinogenèse. Par exemple, ce système peut être employé pour l'étude des substances ou des facteurs impliqués, par exemple, dans la survie ou dans la génération des cellules rétiniennes. Il peut également aider à disséquer la fonction de gènes ou les facteurs impliqués dans la restriction ou la spécification du destin cellulaire. En outre, dans les pays occidentaux, la rétinite pigmentaire (RP) touche 1 individu sur 3500 et la dégénérescence maculaire liée à l'âge (DMLA) affecte 1 % à 3% de la population âgée de plus de 60 ans. La génération in vitro de cellules rétiniennes est aussi un outil prometteur pour fournir une source illimitée de cellules pour l'étude de transplantation cellulaire pour la rétine. SUMMARY IN ENGLISH Stem cells are defined as undifferentiated cells capable of a) proliferation, b) self maintenance (self-renewability), c) production of many differentiated functional postmitotic cells (multipotency), and d) regenerating tissue after injury. For instance, hematopoietic stem cells, located in bone marrow, can expand, divide and generate differentiated cells into the diverse lineages throughout life, the stem cells conserving their status. In the villi crypt, the intestinal stem cells are also able to regenerate the intestine during their life time. The retina is composed of six classes of neurons and one glial cell. All these cell types are produced by the retinal progenitor cell. The peak of photoreceptor production is reached around the first postnatal days in rodents. Thus, at this stage the retina contains highly proliferative cells. In our research, we analyzed the phenotype of these cells and their potential as possible progenitor or stem cells. We also focused on the effect of epigenic factor(s) and cell fate determination. All the proliferating cells isolated from mice postnatal neuroretina harbored the radial glia marker RC2, expressed transcription factors usually found in radial glia (Mash 1, Pax6), and met the criteria of stem cells: high capacity of expansion, maintenance of an undifferentiated state, and multipotency demonstrated by clonal analysis. We analyzed the differentiation seven days after the transfer of the cells in different culture media. In the absence of serum, EGF led to the expression of the neuronal marker β-tubulin-III, and the acquisition of neuronal morphology in 15% of the cells. Analysis of cell proliferation by bromodeoxyuridine incorporation revealed that EGF mainly induced the formation of neurons without stimulating massively cell cycle progression. Moreover, a pulse of 2h EGF stimulation was sufficient to induce neuronal differentiation. Some neurons were committed to the retinal ganglion cell (RGC) phenotype, as revealed by the expression of retinal ganglion markers (Ath5, Brn3b and melanopsin), and in few cases to other retinal phenotypes (photoreceptors (PRs) and bipolar cells). We confirmed that the late RSCs were not restricted over-time and conserved multipotentcy characteristics by generating retinal phenotypes that usually appear at early (RGC) or late (PRs) developmental stages. Our results show that EGF is not only a factor controlling glial development, as previously shown, but also a potent differentiation factor for retinal neurons, at least in vitro. On the other hand, we wanted to find out if the adult human eye contains retina stem cells. The eye of some fishes and amphibians continues to grow during adulthood due to the persistent activity of retinal stem cells (RSCs). In fish, the RSCs are located in the ciliary margin zone (CMZ) at the periphery of the retina. Although, the adult mammalian eye does not grow during adult life, several groups have shown that the adult mouse eye contains retinal stem cells in the homologous zone (i.e. the ciliary margin), in the pigmented epithelium and not in the neuroretina. These RSCs meet some criteria of stem cells. We identified and characterized the human retinal stem cells. We showed that they posses the same features as their rodent counterpart i.e. they self-renew, expand and differentiate into retinal neurons in vitro and in vivo (indicated by immunostaining and microarray analysis). Moreover, they can be greatly expanded while conserving their sternness potential as revealed by the gene expression profile analysis (microarray approach). They also expressed genes common to various stem cells: nucleostemin, nestin, Bmil , Notch2, ABCG2, c-kit and its ligand, as well as cyclin D3 which acts downstream of c-kit. Furthermore, Bmil and Oct-4 were required for RSC proliferation reinforcing their stem cell identity. Our data indicate that the mice postnatal neuroretina and the adult pigmented epithelium of adult human ciliary margin contain retinal stem cells. We developed a system to easily expand and culture RSCs that can be used to investigate the retinogenesis. For example, it can help to screen drugs or factors involved, for instance, in the survival or generation of retinal cells. This could help to dissect genes or factors involved in the restriction or specification of retinal cell fate. In Western countries, retinitis pigmentosa (RP) affects 1 out of 3'500 individuals and age-related macula degeneration (AMD) strikes 1 % to 3% of the population over 60. In vitro generation of retinal cells is thus a promising tool to provide an unlimited cell source for cellular transplantation studies in the retina.

Chronic illness, life style and emotional health in adolescence: results of a cross-sectional survey on the health of 15-20-year-olds in Switzerland.

The objective was to evaluate the prevalence of chronic conditions (CC) in adolescents in Switzerland; to describe their behaviour (leisure, sexuality, risk taking behaviour) and to compare them to those in adolescents who do not have CC in order to evaluate the impact of those conditions on their well-being. The data were obtained from the Swiss Multicentre Adolescent Survey on Health, targeting a sample of 9268 in-school adolescents aged 15 to 20 years, who answered a self-administered questionnaire. Some 11.4% of girls and 9.6% of boys declared themselves carriers of a CC. Of girls suffering from a CC, 25% (versus 13% of non carriers; P=0.007) and 38% of boys (versus 25%; P=0.002) proclaimed not to wear a seatbelt whilst driving. Of CC girls, 6.3% (versus 2.7%; P=0.000) reported within the last 12 months to have driven whilst drunk. Of the girls, 43% (versus 36%; P=0.004) and 47% (versus 39%; P=0.001) were cigarette smokers. Over 32% of boys (versus 27%; P=0.02) reported having ever used cannabis and 17% of girls (versus 13%; P=0.013) and 43% of boys (versus 36%; P=0.002) admitted drinking alcohol. The burden of their illness had important psychological consequences: 7.7% of girls (versus 3.4%; P=0.000) and 4.9% of boys (versus 2.0%; P=0.000) had attempted suicide during the previous 12 months. CONCLUSION: experimental behaviours are not rarer in adolescents with a chronic condition and might be explained by a need to test their limits both in terms of consumption and behaviour. Prevention and specific attention from the health caring team is necessary.

Anthropogenic disturbance as a driver of microspatial and microhabitat segregation of cytotypes of Centaurea stoebe and cytotype interactions in secondary contact zones.

BACKGROUND AND AIMS: In a mixed-ploidy population, strong frequency-dependent mating will lead to the elimination of the less common cytotype, unless prezygotic barriers enhance assortative mating. However, such barriers favouring cytotype coexistence have only rarely been explored. Here, an assessment is made of the mechanisms involved in formation of mixed-ploidy populations and coexistence of diploid plants and their closely related allotetraploid derivates from the Centaurea stoebe complex (Asteraceae). METHODS: An investigation was made of microspatial and microhabitat distribution, life-history and fitness traits, flowering phenology, genetic relatedness of cytotypes and intercytotype gene flow (cpDNA and microsatellites) in six mixed-ploidy populations in Central Europe. KEY RESULTS: Diploids and tetraploids were genetically differentiated, thus corroborating the secondary origin of contact zones. The cytotypes were spatially segregated at all sites studied, with tetraploids colonizing preferentially drier and open microhabitats created by human-induced disturbances. Conversely, they were rare in more natural microsites and microsites with denser vegetation despite their superior persistence ability (polycarpic life cycle). The seed set of tetraploid plants was strongly influenced by their frequency in mixed-ploidy populations. Triploid hybrids originated from bidirectional hybridizations were extremely rare and almost completely sterile, indicating a strong postzygotic barrier between cytotypes. CONCLUSIONS: The findings suggest that tetraploids are later immigrants into already established diploid populations and that anthropogenic activities creating open niches favouring propagule introductions were the major factor shaping the non-random distribution and habitat segregation of cytotypes at fine spatial scale. Establishment and spread of tetraploids was further facilitated by their superior persistence through the perennial life cycle. The results highlight the importance of non-adaptive spatio-temporal processes in explaining microhabitat and microspatial segregation of cytotypes.

Synergistic action of GA-binding protein and glucocorticoid receptor in transcription from the mouse mammary tumor virus promoter.

B lymphocytes are among the first cells to be infected by mouse mammary tumor virus (MMTV), and they play a crucial role in its life cycle. To study transcriptional regulation of MMTV in B cells, we have analyzed two areas of the long terminal repeat (LTR) next to the glucocorticoid receptor binding site, fp1 (at position -139 to -146 from the cap site) and fp2 (at -157 to -164). Both showed B-cell-specific protection in DNase I in vitro footprinting assays and contain binding sites for Ets transcription factors, a large family of proteins involved in cell proliferation and differentiation and oncogenic transformation. In gel retardation assays, fp1 and fp2 bound the heterodimeric Ets factor GA-binding protein (GABP) present in B-cell nuclear extracts, which was identified by various criteria: formation of dimers and tetramers, sensitivity to pro-oxidant conditions, inhibition of binding by specific antisera, and comigration of complexes with those formed by recombinant GABP. Mutations which prevented complex formation in vitro abolished glucocorticoid-stimulated transcription from an MMTV LTR linked to a reporter gene in transiently transfected B-cell lines, whereas they did not affect the basal level. Exogenously expressed GABP resulted in an increased level of hormone response of the LTR reporter plasmid and produced a synergistic effect with the coexpressed glucocorticoid receptor, indicating cooperation between the two. This is the first example of GABP cooperation with a steroid receptor, providing the opportunity for studying the integration of their intracellular signaling pathways.

Expression of MYC, IgM, As Well As Non-Germinal Centre B-Cell Like Immunophenotype and Positive Immunofish Index Predict a Worse Progression Free Survival and Overall Survival in a Series of 670 De Novo Diffuse Large B-Cell Lymphomas Included in Clinical Trials: A GELA Study of the 2003 Program

Introduction: Diffuse large B-cell lymphomas (DLBCL) represent a heterogeneous disease with variable clinical outcome. Identifying phenotypic biomarkers of tumor cells on paraffin sections that predict different clinical outcome remain an important goal that may also help to better understand the biology of this lymphoma. Differentiating non-germinal centre B-cell-like (non-GCB) from Germinal Centre B-cell-like (GCB) DLBCL according to Hans algorithm has been considered as an important immunohistochemical biomarker with prognostic value among patients treated with R-CHOP although not reproducibly found by all groups. Gene expression studies have also shown that IgM expression might be used as a surrogate for the GCB and ABC subtypes with a strong preferential expression of IgM in ABC DLBCL subtype. ImmunoFISH index based on the differential expression of MUM-1, FOXP1 by immunohistochemistry and on the BCL6 rearrangement by FISH has been previously reported (C Copie-Bergman, J Clin Oncol. 2009;27:5573-9) as prognostic in an homogeneous series of DLBCL treated with R-CHOP. In addition, oncogenic MYC protein overexpression by immunohistochemistry may represent an easy tool to identify the consequences of MYC deregulation in DLBCL. Our aim was to analyse by immunohistochemistry the prognostic relevance of MYC, IgM, GCB/nonGCB subtype and ImmunoFISH index in a large series of de novo DLBCL treated with Rituximab (R)-chemotherapy (anthracyclin based) included in the 2003 program of the Groupe d'Etude des Lymphomes de l'Adulte (GELA) trials. Methods: The 2003 program included patients with de novo CD20+ DLBCL enrolled in 6 different LNH-03 GELA trials (LNH-03-1B, -B, -3B, 39B, -6B, 7B) stratifying patients according to age and age-adjusted IPI. Tumor samples were analyzed by immunohistochemistry using CD10, BCL6, MUM1, FOXP1 (according to Barrans threshold), MYC, IgM antibodies on tissue microarrays and by FISH using BCL6 split signal DNA probes. Considering evaluable Hans score, 670 patients were included in the study with 237 (35.4%) receiving intensive R-ACVBP regimen and 433 (64.6%) R-CHOP/R-mini-CHOP. Results: 304 (45.4%) DLBCL were classified as GCB and 366 (54.6%) as non-GCB according to Hans algorithm. 337/567 cases (59.4%) were positive for the ImmunoFISH index (i.e. two out of the three markers positive: MUM1 protein positive, FOXP1 protein Variable or Strong, BCL6 rearrangement). Immunofish index was preferentially positive in the non-GCB subtype (81.3%) compared to the GCB subtype (31.2%), (p<0.001). IgM was recorded as positive in tumor cells in 351/637 (52.4%) DLBCL cases with a preferential expression in non-GCB 195 (53.3%) vs GCB subtype 100(32.9%), p<0.001). MYC was positive in 170/577 (29.5%) cases with a 40% cut-off and in 44/577 (14.2%) cases with a cut-off of 70%. There was no preferential expression of MYC among GCB or non-GCB subtype (p>0.4) for both cut-offs. Progression-free Survival (PFS) was significantly worse among patients with high IPI score (p<0.0001), IgM positive tumor (p<0.0001), MYC positive tumor with a 40% threshold (p<0.001), ImmunoFISH positive index (p<0.002), non-GCB DLBCL subtype (p<0.0001). Overall Survival (OS) was also significantly worse among patients with high IPI score (p<0.0001), IgM positive tumor (p=0.02), MYC positive tumor with a 40% threshold (p<0.01), ImmunoFISH positive index (p=0.02), non-GCB DLBCL subtype (p<0.0001). All significant parameters were included in a multivariate analysis using Cox Model and in addition to IPI, only the GCB/non-GCB subtype according to Hans algorithm predicted significantly a worse PFS among non-GCB subgroup (HR 1.9 [1.3-2.8] p=0.002) as well as a worse OS (HR 2.0 [1.3-3.2], p=0.003). This strong prognostic value of non-GCB subtyping was confirmed considering only patients treated with R- CHOP for PFS (HR 2.1 [1.4-3.3], p=0.001) and for OS (HR 2.3 [1.3-3.8], p=0.002). Conclusion: Our study on a large series of patients included in trials confirmed the relevance of immunohistochemistry as a useful tool to identify significant prognostic biomarkers for clinical use. We show here that IgM and MYC might be useful prognostic biomarkers. In addition, we confirmed in this series the prognostic value of the ImmunoFISH index. Above all, we fully validated the strong and independent prognostic value of the Hans algorithm, daily used by the pathologists to subtype DLBCL.

A regional Industrial Symbiosis methodology and its implementation in Geneva, Switzerland

The Agenda 21 for the Geneva region is the results from a broad consultation process including all local actors. The article 12 stipulates that « the State facilitates possible synergies between economic activities in order to minimize their environmental impacts » thus opening the way for Industrial Ecology (IE) and Industrial Symbiosis (IS). An Advisory Board for Industrial Ecology and Industrial Symbiosis implementation was established in 2002 involving relevant government agencies. Regulatory and technical conditions for IS are studied in the Swiss context. Results reveal that the Swiss law on waste does not hinder by-product exchanges. Methodology and technical factors including geographic, qualitative, quantitative and economical aspects are detailed. The competition with waste operators in a highly developed recycling system is also tackled.The IS project develops an empirical and systematic method for detecting and implementing by-products synergies between industrial actors disseminated throughout the Geneva region. Database management tool for the treatment of input-output analysis data and GIS tools for detecting potentials industrial partners are constantly improved. Potential symbioses for 17 flows (including energy, water and material flows) are currently studied for implementation.

The influence of environmental spatial structure on the life history traits and diversity of species in a metacommunity

Several models have been proposed to understand how so many species can coexist in ecosystems. Despite evidence showing that natural habitats are often patchy and fragmented, these models rarely take into account environmental spatial structure. In this study we investigated the influence of spatial structure in habitat and disturbance regime upon species' traits and species' coexistence in a metacommunity. We used a population-based model to simulate competing species in spatially explicit landscapes. The species traits we focused on were dispersal ability, competitiveness, reproductive investment and survival rate. Communities were characterized by their species richness and by the four life-history traits averaged over all the surviving species. Our results show that spatial structure and disturbance have a strong influence on the equilibrium life-history traits within a metacommunity. In the absence of disturbance, spatially structured landscapes favour species investing more in reproduction, but less in dispersal and survival. However, this influence is strongly dependent on the disturbance rate, pointing to an important interaction between spatial structure and disturbance. This interaction also plays a role in species coexistence. While spatial structure tends to reduce diversity in the absence of disturbance, the tendency is reversed when disturbance occurs. In conclusion, the spatial structure of communities is an important determinant of their diversity and characteristic traits. These traits are likely to influence important ecological properties such as resistance to invasion or response to climate change, which in turn will determine the fate of ecosystems facing the current global ecological crisis.