Biochemical characterization of recombinant human telomerase

Résumé Les télomères sont les structures ADN-protéines des extrémités des chromosomes des eucaryotes. L'ADN télomérique est constitué de courtes séquences répétitives. L'intégrité des télomères est essentielle pour protéger les extrémités des chromosomes contre les systèmes de dégradations et pour les distinguer des cassures de l'ADN double brin. Parce que la machinerie de la réplication de l'ADN n'est pas capable de répliquer l'extrémité des chromosomes, les télomères raccourcissent au fur et à mesure des cycles de réplication. Dès que les télomères atteignent une longueur critique, leur structure protectrice est perdue. Cela induit un signal de dommage de l'ADN et l'arrêt du cycle cellulaire. Pour contrebalancer le raccourcissement des télomères, les cellules qui s'auto régénèrent, dont les cellules de la moelle osseuse, les lymphocytes activés et 80-90% des cellules cancéreuses, expriment la télomérase. C'est une ribonucléoprotéine qui a la capacité de synthétiser des séquences télomériques par transcription inverse d'une courte séquence contenue dans sa propre sous-unité ARN avec laquelle elle est associée. La télomérase humaine est une enzyme processive au niveau de l'addition des nucléotides et aussi des répétitions télomériques. La télomérase de levure et la télomérase humaine sont toutes deux dimériques et il a été montré que la télomérase humaine recombinante contient deux ARN qui coopèrent pour fonctionner ainsi que deux sous-unités catalytiques. Cependant, il n'a pas encore été montré quel est le rôle de la dimérisation dans l'activité de la télomérase. Afin d'élucider ce rôle, nous avons exprimé, reconstitué et purifié la télomérase humaine dimérique recombinante. Et pour étudier l'effet d'ARN mutants sur l'activité de la télomérase, nous avons développé une méthode pour reconstituer et enrichir en hétérodimères de télomérase. Les hétérodimères contiennent une sous-unité ARN sauvage et une sous-unité ARN mutée au niveau de la séquence de la matrice. Sur l'ARN muté nous avons introduit une étiquette aptamer ARN-S1 puis nous avons purifié la télomérase via l'etiquette Si. Nous avons montré que la dimérisation est essentielle pour l'activité de la télomérase. Nos données indiquent que chaque télomérase du dimère allonge leur substrat, l'ADN télomérique, indépendamment l'une de l'autre à chaque cycle d'élongation mais que l'addition itérative de répétitions télomériques nécessite une coopération entre les deux télomérases du dimère. Nous proposons donc un modèle dans lequel les deux télomérases du dimères se lient et allongent deux substrats télomères et que pendant l'élongation processive les deux enzymes subissent un changement de conformation de manière coordonnée, ce changement va permettre le repositionnement des substrats pour d'autres cycles d'additions de répétitions télomériques. Dyskeratosis congenita est une maladie mortelle due majoritairement au disfonctionnement de la moelle osseuse. Dans la forme autosomale de la maladie, l'ARN de la télomérase contient des mutations. En utilisant notre système de reconstitution, nous avons montré que ces ARN mutés, qui ont perdu leur activité enzymatique dans le cas d'un homodimère de mutants, sont dominant négatifs quand ils sont présents dans les hétérodimères sauvage/mutant. Cet effet trans-dominant négatif pourrait contribuer à la progression de la maladie. Abstract Telomeres are protein-DNA structures at the ends of linear eukaryotic chromosomes. The telomeric DNA consists of tandemly repeated sequences. Telomeric integrity is essential to protect chromosomal ends from nucleolytic degradation and to prevent their recognition as DNA double strand breaks. Due to the inability of the conventional DNA replication machinery to replicate terminal DNA stretches, telomeres shorten with continuous rounds of DNA replication. As soon as telomeres reach a critical length, their protective structure is lost and the deprotected telomeres will induce a DNA damage response leading to cell cycle arrest. To counteract telomere shortening, self-renewing cells, including bone marrow cells, activated lymphocytes and 80-90% of cancer cells express the cellular reverse transcriptase telomerase, which has the capacity to synthesize telomeric repeats by reverse transcription of a short template sequence encoded by its stably associated RNA subunit. Human telomerase is a processive enzyme for nucleotide as well as repeat addition. Both yeast and human telomerase are dimeric enzymes and recombinant human telomerase has been shown to contain two functionally cooperating RNAs and most probably also two protein subunits. However, it has remained unclear how dimerization may contribute to telomerase activity. To study the role of dimerization, we expressed, reconstituted and purified recombinant human telomerase. We also developed a new method to reconstitute and enrich for telomerase heterodimers containing wild-type (wt) and mutant telomerase RNA subunits. To this end we introduced an S1-RNA-aptamer tag into telomerase RNA and purified telomerase reconstituted with a mixture of untagged and tagged RNA via the S1-tag. Using this experimental system, we introduced template mutations in the tagged RNA subunit and examined the effect of mutant RNAs on wt telomerase activity in wt/mutant heterodimers. We obtained evidence that dimerization is essential for telomerase activity. Our data indicate that the two subunits elongate telomere substrates independently of each other during single rounds of elongation, but that iterative addition of telomeric repeats requires cooperation between the two subunits. We suggest a model, in which dimeric telomerases bind and elongate two telomere substrates and that the two subunits undergo coordinated conformational changes during processive elongation that enable repositioning the substrates for subsequent rounds of repeat addition. Dyskeratosis congenita is a multisystemic disease with bone marrow failure as the major cause of death. The autosomal form of this disease was found to harbor mutations in the telomerase RNA. Using our reconstitution system, we tested whether mutant dyskeratosis telomerase RNAs behaved in a dominant negative manner. We observed that dyskeratosis telomerase RNA mutants, which lacked enzymatic activity were dominant negative, when present in wt/ mutant heterodimers. The transdominant negative effect of these mutants may contribute to disease progression.

Molecular genetics of rare hereditary diseases via genome-wide and integrated approaches

ABSTRACTThe Online Mendelian Inheritance in Man database (OMIM) reports about 3000 Mendelian diseases of known causal gene and about 2000 that remain to be mapped. These cases are often difficult to solve because of the rareness of the disease, the structure of the family (too big or too small) or the heterogeneity of the phenotype. The goal of this thesis is to explore the current genetic tools, before the advent of ultra high throughput sequencing, and integrate them in the attempt to map the genes behind the four studied cases. In this framework we have studied a small family with a recessive disease, a modifier gene for the penetrance of a dominant mutation, a large extended family with a cardiac phenotype and clinical and/or allelic heterogeneity and we have molecularly analyzed a balanced chromosomal translocation.RESUMELa base de données des maladies à transmission mendélienne, Online Mendelian Inheritance in Man (OMIM), contient environ 3000 affections à caractère mendélien pour lesquelles le gène responsable est connu et environ 2000 qui restent à élucider.Les cas restant à résoudre sont souvent difficiles soit par le caractère intrinsèquement rare de ces maladies soit à cause de difficultés structurelles (famille trop petite ou trop étendue) ou hétérogénéité du phénotype ou génétique. Cette thèse s'inscrit avant l'arrivée des nouveaux outils de séquençage à haut débit. Son but est d'explorer les outils génétiques actuels, et de les intégrer pour trouver les gènes impliqués dans quatre cas représentant chacun une situation génétique différente : nous avons étudié une famille de quatre individus avec une transmission récessive, recherché un gène modificateur de la pénétrance de mutations dominantes, étudié une famille étendue présentant un phénotype cardiaque cliniquement et/ou allèliquement hétérogène et nous avons fait l'analyse moléculaire d'une translocation chromosomique balancée.

Multiple causes of the evolution of dispersal in metapopulations

Abstract This work investigates the outcome of the interaction of the multiple causes of selection acting on dispersal in metapopulations. Dispersal, defined here as the ability of individuals to move out of their natal population to reproduce in an other one, has three main causes. First, population variability, as caused by random population extinctions, induces high incentives to disperse through the probability to recolonize an empty population and thus to escape competition for space. This adds to the second cause, kin competition avoidance where individuals in a crowded patch will benefit from the release of competition with relatives caused by dispersal. Dispersal may thus be viewed as an altruistic act. Third, dispersal might evolve as a strategy of avoiding inbred matings which are expected to bear fitness costs due to the presence of a mutation load. The interaction of inbreeding avoidance and kin competition is explored in chapter 2. Conditions conducive to the establishment of a high relatedness within population are expected to induce high dispersal through both kin competition avoidance and inbreeding avoidance. However, the dynamics of inbreeding depression is bound to depend on the level of gene flow as well as on the deleterious mutation parameters. Mutations more prone to settle a high level of inbreeding depression will select for increased dispersal. Chapter 3 investigates the effect of the mating system on the joint dynamics of dispersal and inbreeding depression. Higher inbreeding rates as those found in various mating systems lead to a more efficient purge of the deleterious mutations. However, this decrease in the costs of inbreeding are usually accompanied by a higher within deme relatedness which balances the decreased effect of inbreeding avoidance on the evolution of dispersal. Finally, population turnover, as found in most natural populations has a dual effect on dispersal. Indeed, it increases dispersal by the increased probability of winning a breeding slot in extinct demes it creates but, on the other hand, it counter-selects for dispersal through the slow establishment of unsaturated demic conditions which contribute to lower the local competition for space. Résumé Ce travail se propose d'étudier les effets conjoints des multiples causes de l'évolution de la dispersion en métapopulation. La dispersion, définie ici comme étant la capacité de quitter sa population d'origine pour se reproduire dans une antre population, possède trois principales causes. Premièrement, l'extinction aléatoire de populations sélectionne pour plus de dispersion car elle augmente la Probabilité de recoloniser un patch éteint et donc d'échapper à la compétition locale. La seconde cause, l'évitement de la compétition de parentèle, sélectionne pour plus de dispersion par les bénéfices qu'elle apporte par diminution de la compétition entre individus apparentés. Troisièmement, la dispersion évolue "comme stratégie d'évitement de la dépression de consanguinité présente dans des petites populations isolées. L'interaction entre l'évitement de la consanguinité et de la compétition de parentèle est étudiée dans le chapitre 2. Les conditions conduisant à l'établissement d'un fort apparentement à l'intérieur des populations sont celles qui génèrent le plus de sélection pour la dispersion. Cependant, la dynamique de la dépression de consanguinité est dépendante de la dispersion entre populations ainsi que des paramètres des mutations délétères. Les mutations créant le plus de dépression de consanguinité sont celles qui sélectionneront le plus pour de la dispersion. Le chapitre 3 s'intéresse aux effets du système de reproduction sur la dynamique conjointe du fardeau de mutation et de la dispersion. La purge des mutations délétère étant plus sévère dans des conditions de forte consanguinité, elle diminue les coûts de la consanguinité mais est habituellement accompagné par une augmentation de l'apparentement et donc l'effet peut être neutre sur la dispersion. Finalement, le turnover de populations a un effet dual sur la dispersion. La dispersion est sélectionnée par l'augmentation de la probabilité de gagner une place de reproduction dans des patchs éteints mais elle est également contre sélectionnée par la désaturation des patchs causée par l'extinction et la diminution de la compétition pour l'espace qui intervient dans ce cas.

Responsiveness to a physiological regimen of GnRH therapy and relation to genotype in women with isolated hypogonadotropic hypogonadism.

CONTEXT: Isolated hypogonadotropic hypogonadism (IHH) is caused by defective GnRH secretion or action resulting in absent or incomplete pubertal development and infertility. Most women with IHH ovulate with physiological GnRH replacement, implicating GnRH deficiency as the etiology. However, a subset does not respond normally, suggesting the presence of defects at the pituitary or ovary. OBJECTIVES: The objective of the study was to unmask pituitary or ovarian defects in IHH women using a physiological regimen of GnRH replacement, relating these responses to genes known to cause IHH. DESIGN, SETTING, AND SUBJECTS: This study is a retrospective analysis of 37 IHH women treated with iv pulsatile GnRH (75 ng/kg per bolus). MAIN OUTCOME MEASURES: Serum gonadotropin and sex steroid levels were measured, and 14 genes implicated in IHH were sequenced. RESULTS: During their first cycle of GnRH replacement, normal cycles were recreated in 60% (22 of 37) of IHH women. Thirty percent of women (12 of 37) demonstrated an attenuated gonadotropin response, indicating pituitary resistance, and 10% (3 of 37) exhibited an exaggerated FSH response, consistent with ovarian resistance. Mutations in CHD7, FGFR1, KAL1, TAC3, and TACR3 were documented in IHH women with normal cycles, whereas mutations were identified in GNRHR, PROKR2, and FGFR1 in those with pituitary resistance. Women with ovarian resistance were mutation negative. CONCLUSIONS: Although physiological replacement with GnRH recreates normal menstrual cycle dynamics in most IHH women, hypogonadotropic responses in the first week of treatment identify a subset of women with pituitary dysfunction, only some of whom have mutations in GNRHR. IHH women with hypergonadotropic responses to GnRH replacement, consistent with an additional ovarian defect, did not have mutations in genes known to cause IHH, similar to our findings in a subset of IHH men with evidence of an additional testicular defect.

In house reverse membrane hybridisation assay versus GenoType MTBDRplus and their performance to detect mutations in the genes rpoB, katG and inhA

Drug-resistant tuberculosis (TB) threatens global TB control and is a major public health concern in several countries. We therefore developed a multiplex assay (LINE-TB/MDR) that is able to identify the most frequent mutations related to rifampicin (RMP) and isoniazid (INH) resistance. The assay is based on multiplex polymerase chain reaction, membrane hybridisation and colorimetric detection targeting of rpoB and katG genes, as well as the inhA promoter, which are all known to carry specific mutations associated with multidrug-resistant TB (MDR-TB). The assay was validated on a reference panel of 108 M. tuberculosis isolates that were characterised by the proportion method and by DNA sequencing of the targets. When comparing the performance of LINE-TB/MDR with DNA sequencing, the sensitivity, specificity and agreement were 100%, 100% and 100%, respectively, for RMP and 77.6%, 90.6% and 88.9%, respectively, for INH. Using drug sensibility testing as a reference standard, the performance of LINE-TB/MDR regarding sensitivity, specificity and agreement was 100%, 100% and 100% (95%), respectively, for RMP and 77%, 100% and 88.7% (82.2-95.1), respectively, for INH. LINE-TB/MDR was compared with GenoType MTBDRplus for 65 isolates, resulting in an agreement of 93.6% (86.7-97.5) for RIF and 87.4% (84.3-96.2) for INH. LINE-TB/MDR warrants further clinical validation and may be an affordable alternative for MDR-TB diagnosis.

Claudin-19 mutations and clinical phenotype in Spanish patients with familial hypomagnesemia with hypercalciuria and nephrocalcinosis.

Familial hypomagnesemia with hypercalciuria and nephrocalcinosis is an autosomal recessive tubular disorder characterized by excessive renal magnesium and calcium excretion and chronic kidney failure. This rare disease is caused by mutations in the CLDN16 and CLDN19 genes. These genes encode the tight junction proteins claudin-16 and claudin-19, respectively, which regulate the paracellular ion reabsorption in the kidney. Patients with mutations in the CLDN19 gene also present severe visual impairment. Our goals in this study were to examine the clinical characteristics of a large cohort of Spanish patients with this disorder and to identify the disease causing mutations. We included a total of 31 patients belonging to 27 unrelated families and studied renal and ocular manifestations. We then analyzed by direct DNA sequencing the coding regions of CLDN16 and CLDN19 genes in these patients. Bioinformatic tools were used to predict the consequences of mutations. Clinical evaluation showed ocular defects in 87% of patients, including mainly myopia, nystagmus and macular colobomata. Twenty two percent of patients underwent renal transplantation and impaired renal function was observed in another 61% of patients. Results of the genetic analysis revealed CLDN19 mutations in all patients confirming the clinical diagnosis. The majority of patients exhibited the previously described p.G20D mutation. Haplotype analysis using three microsatellite markers showed a founder effect for this recurrent mutation in our cohort. We also identified four new pathogenic mutations in CLDN19, p.G122R, p.I41T, p.G75C and p.G75S. A strategy based on microsequencing was designed to facilitate the genetic diagnosis of this disease. Our data indicate that patients with CLDN19 mutations have a high risk of progression to chronic renal disease.

Recurrent mutations in the CDKL5 gene: Genotype-phenotype relationships.

Mutations in the cyclin-dependent kinase-like 5 gene (CDKL5) have been described in epileptic encephalopathies in females with infantile spasms with features that overlap with Rett syndrome. With more than 80 reported patients, the phenotype of CDKL5-related encephalopathy is well-defined. The main features consist of seizures starting before 6 months of age, severe intellectual disability with absent speech and hand stereotypies and deceleration of head growth, which resembles Rett syndrome. However, some clinical discrepancies suggested the influence of genetics and/or environmental factors. No genotype-phenotype correlation has been defined and thus there is a need to examine individual mutations. In this study, we analyzed eight recurrent CDKL5 mutations to test whether the clinical phenotype of patients with the same mutation is similar and whether patients with specific CDKL5 mutations have a milder phenotype than those with other CDKL5 mutations. Patients bearing missense mutations in the ATP binding site such as the p.Ala40Val mutation typically walked unaided, had normocephaly, better hand use ability, and less frequent refractory epilepsy when compared to girls with other CDKL5 mutations. In contrast, patients with mutations in the kinase domain (such as p.Arg59X, p.Arg134X, p.Arg178Trp/Pro/Gln, or c.145 + 2T > C) and frameshift mutations in the C-terminal region (such as c.2635_2636delCT) had a more severe phenotype with infantile spasms, refractory epileptic encephalopathy, absolute microcephaly, and inability to walk. It is important for clinicians to have this information when such patients are diagnosed. © 2012 Wiley Periodicals, Inc.

Characterization of SKI-1/S1P-mediated processing of Arenavirus glycoprotein precursors

Arenaviruses are rodent-born world-wide distributed negative strand RNA viruses that comprise a number of important human pathogens including Lassa virus (LASV) which causes more than 3 00'000 infections annually in Western Africa. Lymphocytic choriomeningitis virus (LCMV) is the prototypic member of the arenavirus family, which is divided in two major subgroups according to serological properties and geographical distribution, the Old World and New World arenaviruses. The envelope glycoprotein precursors (GPCs) of arenaviruses have to undergo proteolytic processing to acquire biological function and to be incorporated into progeny virions. A cellular enzyme is responsible for this processing: the Subtilisin Kexin Isozyme-1 or Site-1 protease (SKI- 1/S1P). In this thesis we have studied the relationship between SKI-1/S1P and the envelope GPs of arenaviruses. In a first project, we investigated the molecular interactions between SKI-1/SIP and arenavirus GPCs. Using SKI-1/SIP mutants, we confirmed previously published observations locating LCMV GPC and LASV GPC processing in the Late Golgi/TGN and ER/cis-Golgi, respectively. A single mutation in the cleavage site of LCMV was sufficient to re-locate SKI- 1/SIP-mediated processing from the late Golgi/TGN to the ER/cis-Golgi. We then demonstrated that the transmembrane domain, the C-terminal tail and the phosphorylation sites of SKI-1/S1P are dispensable for GPC processing. Additionally we identified a SKI- 1/S1P mutant defective for autoprocessing at site Β, B' that was selectively impaired in processing of viral GPCs but not cellular substrates. We also showed that a soluble variant of SKI-1/SIΡ was unable to cleave envelope GPs at the cell surface when added in the culture medium. This study highlighted a new target for small molecule inhibitors that would specifically impair GPC but not cellular substrate processing. In a second project, we identified and characterized two residues: LASV GPC Y253 and SKI-1/S1P Y285 that are important for the SKI-1/SIP-mediated LASV GPC cleavage. An alignment of GPC sequences revealed a conserved aromatic residue in P7 position in the GPCs of Old World and Clade C of New World arenaviruses. Mutations in GPC at position P7 impaired processing efficiency. In SKI-1/S1P, mutating Y285 into A negatively affected processing of substrates containing aromatic residues in P7, without affecting others. This property could be used to develop specific drugs targeting SKI-1/SIP-mediated cleavage of LASV GPC without affecting cellular substrates. As a third project we studied the role of the SKI-1/SIP-mediated processing and the unusual stable signal peptide (SSP) for the folding and secretion of soluble forms of the ectodomain of LASV and LCMV glycoproteins. We provide evidence that the transmembrane domain and the cytosolic tail are crucial for the stability of the prefusion conformation of arenavirus GP and that the SSP is required for transport and processing of full-length GP, but not the soluble ectodomain per se. Taken together, these results will lead to a better understanding of the complex interactions between arenavirus GPCs and SKI-1/S IP, paving the avenue for the development of novel anti-arenaviral therapeutics. - Les Arenavirus sont des virus à ARN négatif distribués mondialement et portés par les rongeurs. Cette famille de virus comprend des virus hautement pathogènes pour l'homme comme le virus de Lassa (LASV) qui cause plus de 300Ό00 infections par année en Afrique de l'Ouest. Le virus de la chorioméningite lymphocytaire (LCMV) est le représentant de cette famille qui est divisée en deux sous-groupes selon des critères sérologiques et de distributions géographiques: arenavirus du Nouveau et de l'Ancien monde. Les glycoprotéines d'enveloppe de ces virus (GPCs) doivent être clivées pour être incorporées dans le virus et ainsi lui permettre d'être infectieux. Une enzyme cellulaire est responsable de ce clivage : la Subtilisin Kexin Isozyme-1 ou protéase Site-1 (SKI-l/SlP). Dans cette thèse, nous avons étudié la relation entre cette enzyme cellulaire et les GPs des arenavirus. Dans un premier temps, nous avons étudié les interactions moléculaires entre SKI- 1/S1P et GPC. A l'aide de mutants de SKI-l/SlP, nous avons confirmé des résultats précédemment publiés montrant que les glycoprotéines d'enveloppe de LASV sont clivés dans le réticulum endoplasmique/cis-Golgi alors que celles de LCMV sont clivées dans le Golgi tardif/TGN. Une seule mutation dans le site de clivage de la glycoprotéine de LCMV est suffisante pour changer le compartiment cellulaire dans lequel est clivée cette glycoprotéine. Ensuite, nous avons démontré que le domaine transmembranaire, la partie cytosolique C-terminale ainsi que les sites de phosphorylations de cette enzyme ne sont pas indispensables pour permettre le clivage de GPC. De plus, nous avons identifié un mutant de SKI-l/SlP dans lequel Γ autoprocessing au site B,B' est impossible, incapable de cliver GPC mais toujours pleinement fonctionnelle envers ses substrats cellulaires. Nous avons également démontré qu'une forme soluble de SKI-l/SlP ajoutée dans le milieu de culture n'est pas capable de couper GPC à la surface de la cellule. Cette étude a défini une nouvelle cible potentielle pour un médicament qui inhiberait le clivage des glycoprotéines des arenavirus sans affecter les processus normaux de la cellule. Dans un second project, nous avons identifié deux acides aminés, LASV GPC Y253 et SKI-l/SlP Y285, qui sont important pour le clivage de LASV GPC. Un alignement des séquences de clivage des GPCs a montré qu'un résidu aromatique est conservé en position P7 du site de clivage chez tous les arenavirus de l'Ancien monde et dans le clade C des arenavirus du Nouveau monde. Une mutation de cet acide aminée dans GPC réduit l'efficacité de clivage par SKI-l/SlP. Mutation de la tyrosine 285 de SKI-l/SlP en alanine affecte négativement le clivage des substrats contenant un résidu aromatique en position P7 sans affecter les autres. Cette propriété pourrait être utilisée pour le développement de médicaments spécifiques ciblant le clivage de GPC. Finalement, nous avons étudié le rôle du processing accomplit par SKI-l/SlP et du signal peptide pour le pliage et la sécrétion de formes solubles des glycoprotéines de LASV et LCMV. Nous avons montré que le domaine transmembranaire et la partie cytosolique de GP sont crucials pour la stabilité de la conformation pre-fusionnelle des GPs et que SSP est nécessaire pour le transport et le processing de GP, mais pas de son ecto-domaine soluble. En conclusion, les résultats obtenus durant cette thèse permettrons de mieux comprendre les interactions complexes entre SKI-l/SlP et les glycoprotéines des arenavirus, ouvrant le chemin pour le développement de nouveaux médicaments anti-arénaviraux.

Association of socioeconomic status with overall and cause specific mortality in the republic of seychelles : results from a cohort study in the african region

BACKGROUND: Low socioeconomic status (SES) is consistently associated with higher mortality in high income countries. Only few studies have assessed this association in low and middle income countries, mainly because of sparse reliable mortality data. This study explores SES differences in overall and cause-specific mortality in the Seychelles, a rapidly developing small island state in the African region. METHODS: All deaths have been medically certified over more than two decades. SES and other lifestyle-related risk factors were assessed in a total of 3246 participants from three independent population-based surveys conducted in 1989, 1994 and 2004. Vital status was ascertained using linkage with vital statistics. Occupational position was the indicator of SES used in this study and was assessed with the same questions in the three surveys. RESULTS: During a mean follow-up of 15.0 years (range 0-23 years), 523 participants died (overall mortality rate 10.8 per 1000 person-years). The main causes of death were cardiovascular disease (CVD) (219 deaths) and cancer (142 deaths). Participants in the low SES group had a higher mortality risk for overall (HR = 1.80; 95% CI: 1.24-2.62), CVD (HR = 1.95; 1.04-3.65) and non-cancer/non-CVD (HR = 2.14; 1.10-4.16) mortality compared to participants in the high SES group. Cancer mortality also tended to be patterned by SES (HR = 1.44; 0.76-2.75). Major lifestyle-related risk factors (smoking, heavy drinking, obesity, diabetes, hypertension, hypercholesterolemia) explained a small proportion of the associations between low SES and all-cause, CVD, and non-cancer/non-CVD mortality. CONCLUSIONS: In this population-based study assessing social inequalities in mortality in a country of the African region, low SES (as measured by occupational position) was strongly associated with overall, CVD and non-cancer/non-CVD mortality. Our findings support the view that the burden of non-communicable diseases may disproportionally affect people with low SES in low and middle income countries.

Coxiella burnetii as a possible cause of autoimmune liver disease: a case report.

INTRODUCTION: Q fever is a zoonotic infection that may cause severe hepatitis. Q-fever hepatitis has not yet been associated with autoimmune hepatitis and/or primary biliary cirrhosis. CASE PRESENTATION: We describe a 39-year-old man of Sri Lankan origin with chronic Q-fever hepatitis who developed autoantibodies compatible with autoimmune hepatitis/primary biliary cirrhosis overlap syndrome. Ursodeoxycholic acid in addition to antibiotic therapy markedly improved hepatic enzyme levels suggesting that autoimmunity, potentially triggered by the underlying infection, was involved in the pathogenesis of liver damage. CONCLUSION: We suggest that Coxiella burnetii might trigger autoimmune liver disease. Patients with Q-fever hepatitis who respond poorly to antibiotics should be investigated for serological evidence of autoimmune hepatitis, primary biliary cirrhosis or overlap syndrome, as these patients could benefit from adjunctive therapy with ursodeoxycholic acid. Conversely, C. burnetii serology might be necessary in patients with autoimmune liver disease in order to exclude underlying Coxiella infection.

Oseltamivir-resistant influenza A(H1N1)pdm2009 strains found in Brazil are endowed with permissive mutations, which compensate the loss of fitness imposed by antiviral resistance

The 2009 pandemic influenza A virus outbreak led to the systematic use of the neuraminidase (NA) inhibitor oseltamivir (OST). Consequently, OST-resistant strains, carrying the mutation H275Y, emerged in the years after the pandemics, with a prevalence of 1-2%. Currently, OST-resistant strains have been found in community settings, in untreated individuals. To spread in community settings, H275Y mutants must contain additional mutations, collectively called permissive mutations. We display the permissive mutations in NA of OST-resistant A(H1N1)pdm09 virus found in Brazilian community settings. The NAs from 2013 are phylogenetically distinct from those of 2012, indicating a tendency of positive selection of NAs with better fitness. Some previously predicted permissive mutations, such as V241I and N369K, found in different countries, were also detected in Brazil. Importantly, the change D344N, also predicted to compensate loss of fitness imposed by H275Y mutation, was found in Brazil, but not in other countries in 2013. Our results reinforce the notion that OST-resistant A(H1N1)pdm09 strains with compensatory mutations may arise in an independent fashion, with samples being identified in different states of Brazil and in different countries. Systematic circulation of these viral strains may jeopardise the use of the first line of anti-influenza drugs in the future.

All-cause mortality in the cohorts of the Spanish AIDS Research Network (RIS) compared with the general population: 1997-2010.

BACKGROUND Combination antiretroviral therapy (cART) has produced significant changes in mortality of HIV-infected persons. Our objective was to estimate mortality rates, standardized mortality ratios and excess mortality rates of cohorts of the AIDS Research Network (RIS) (CoRIS-MD and CoRIS) compared to the general population. METHODS We analysed data of CoRIS-MD and CoRIS cohorts from 1997 to 2010. We calculated: (i) all-cause mortality rates, (ii) standardized mortality ratio (SMR) and (iii) excess mortality rates for both cohort for 100 person-years (py) of follow-up, comparing all-cause mortality with that of the general population of similar age and gender. RESULTS Between 1997 and 2010, 8,214 HIV positive subjects were included, 2,453 (29.9%) in CoRIS-MD and 5,761 (70.1%) in CoRIS and 294 deaths were registered. All-cause mortality rate was 1.02 (95% CI 0.91-1.15) per 100 py, SMR was 6.8 (95% CI 5.9-7.9) and excess mortality rate was 0.8 (95% CI 0.7-0.9) per 100 py. Mortality was higher in patients with AIDS, hepatitis C virus (HCV) co-infection, and those from CoRIS-MD cohort (1997-2003). CONCLUSION Mortality among HIV-positive persons remains higher than that of the general population of similar age and sex, with significant differences depending on the history of AIDS or HCV coinfection.

Lifetime alcohol use and overall and cause-specific mortality in the European Prospective Investigation into Cancer and nutrition (EPIC) study.

OBJECTIVES To investigate the role of factors that modulate the association between alcohol and mortality, and to provide estimates of absolute risk of death. DESIGN The European Prospective Investigation into Cancer and nutrition (EPIC). SETTING 23 centres in 10 countries. PARTICIPANTS 380 395 men and women, free of cancer, diabetes, heart attack or stroke at enrolment, followed up for 12.6 years on average. MAIN OUTCOME MEASURES 20 453 fatal events, of which 2053 alcohol-related cancers (ARC, including cancers of upper aerodigestive tract, liver, colorectal and female breast), 4187 cardiovascular diseases/coronary heart disease (CVD/CHD), 856 violent deaths and injuries. Lifetime alcohol use was assessed at recruitment. RESULTS HRs comparing extreme drinkers (≥30 g/day in women and ≥60 g/day in men) to moderate drinkers (0.1-4.9 g/day) were 1.27 (95% CI 1.13 to 1.43) in women and 1.53 (1.39 to 1.68) in men. Strong associations were observed for ARC mortality, in men particularly, and for violent deaths and injuries, in men only. No associations were observed for CVD/CHD mortality among drinkers, whereby HRs were higher in never compared to moderate drinkers. Overall mortality seemed to be more strongly related to beer than wine use, particularly in men. The 10-year risks of overall death for women aged 60 years, drinking more than 30 g/day was 5% and 7%, for never and current smokers, respectively. Corresponding figures in men consuming more than 60 g/day were 11% and 18%, in never and current smokers, respectively. In competing risks analyses, mortality due to CVD/CHD was more pronounced than ARC in men, while CVD/CHD and ARC mortality were of similar magnitude in women. CONCLUSIONS In this large European cohort, alcohol use was positively associated with overall mortality, ARC and violent death and injuries, but marginally to CVD/CHD. Absolute risks of death observed in EPIC suggest that alcohol is an important determinant of total mortality.