Large TCR diversity of virus-specific CD8 T cells provides the mechanistic basis for massive TCR renewal after antigen exposure.

Ex vivo analysis of virus-specific CD8 T cell populations by anchored PCR has shown that the CD8 TCR repertoire was less oligoclonal (seven to nine clonotypes per individual epitope) than previously thought. In the current study, TCR diversity was investigated by assessing both the overall TCR β-chain variable regions usage as well as the CDR3 regions in ex vivo-isolated CMV- and EBV-specific CD8 T cells from 27 healthy donors. The average number of clonotypes specific to most single viral epitopes comprised between 14 and 77. Changes in the CD8 TCR repertoire were also longitudinally assessed under conditions of HIV-1 chronic infection (i.e., in patients with suppressed virus replication and after treatment interruption and Ag re-exposure). The results showed that a large renewal (≤80%) of the TRB repertoire occurred after Ag re-exposure and was eventually associated with an increased T cell recognition functional avidity. These results demonstrate that the global CD8 TCR repertoire is much more diverse (≤9-fold) than previously estimated and provide the mechanistic basis for supporting massive repertoire renewal during chronic virus infection and Ag re-exposure.

Origine et évolution de la réhabilitation psychosociale

The main historical stages of the social rehabilitation of the mentally-ill patients show that the psychiatric hospital centred approach has been progressively cast off and therefore the creation of intermediate institutions and ambulatory care integrated in the city has been favoured. This has allowed the progressive development of the psychosocial rehabilitation. This reorientation of the medical practice towards the community was based on two specific and corollary approaches: the deinstitutionalisation and the rehabilitation, which have the common objective to facilitate the return of the patient in the natural social community. The psychosocial rehabilitation includes the deinstitutionalisation and the return to the community, in a holistic approach aiming at compensating for the psychosocial handicap induced by the mental illness. The concept of the psychosocial rehabilitation itself has been progressively elaborated over time. The initial enthusiasm was followed by a period of progressive disillusion, which was finally followed by the development of the psychosocial rehabilitation as a true specific clinical discipline, a topic in medical education and in scientific research

Staphylococcus aureus clfB and spa alleles of the repeat regions are segregated into major phylogenetic lineages.

To reliably differentiate among Staphylococcus aureus isolates we recently developed the Double Locus Sequence Typing (DLST) based on the analysis of partial sequences of clfB and spa genes. This method is highly discriminatory and gives unambiguous definition of types. The highly clonal population structure of S. aureus suggests that isolates with identical clfB or spa alleles belong to the same clonal complex (CC) defined by Multi-Locus Sequence Typing (MLST). To test this hypothesis as well as to investigate putative intra-CC genetic structure, we analyzed a total of 289 isolates (186 MSSA and 103 MRSA) with DLST-, spa- and MLST-typing. Among the 289 strains, 242 were clustered into 7 major MLST CCs, 40 into minor CCs and 7 were not grouped into CCs. A total of 205 DLST- and 129 spa-types were observed. With one exception, all DLST-clfB, DLST-spa and spa-type alleles were segregated into CCs. DLST-types sharing an identical allele (clfB or spa) were clustered using eBURST. Except for one strain, all isolates from each DLST cluster belonged to the same CC. However, using both DLST- and spa-typing we were not able to disclose a clear intra-CC structure. Nevertheless, the high diversity of these loci confirmed that they are good markers for local epidemiological investigations.

Mémoire pour servir à l'itinéraire de Mgr le Marquis de Paulmy, depuis St-Jean-Pied-de-Port jusqu'à Mendionde

Ancien possesseur : Argenson, Antoine-René de Voyer (1722-1787 ; marquis de Paulmy d')

Bilan préopératoire pour la chirurgie cardio-vasculaire en urgence [Preoperative assessment in emergency cardiovascular surgery].

In the emergency situation, preoperative patient work-up for cardio-vascular surgery is quite different from the elective setting. We have analyzed a consecutive series of 5576 cases out of which 823 underwent emergency procedures (14.8%). The most frequent problems requiring emergent intervention were peripheral vascular (186 cases; 22.6% of the emergent procedure), followed by coronary artery disease (156 cases; 19.0%), thoracic aortic aneurysms (86 cases; 10.4%), abdominal aortic aneurysms (54 cases; 6.6%), congenital heart disease (36 cases: 4.4%), heart and heart lung transplantation (31 cases; 3.8%), problems with cardiac rythm (25 cases: 3.0%), and others (267 cases: 32.4%). Classification by proportion of urgent procedures with reference to elective operations shows a different picture. As a matter of fact transplantations were always emergency procedures (100%), whereas repair of aortic dissections type A and B was an emergency procedure in 81.5%. Emergency thoracic and abdominal aortic aneurysm repair accounted for 30% and 20% respectively and the corresponding proportion for peripheral vascular surgery is 19%. However, emergency surgery for acute coronary ischemia, valvular and congenital heart disease accounted for somewhat less than 10% for each group of these pathologies. Systematic pre-operative diagnostic work-up is a recognized tool for procedure related risk assessment and superior management of diseases. However, hemodynamic instability and other time related events correlated with negative outcome, are the main driving forces for accelerated diagnostic pathways

Role of Notch signaling in epidermis and appendages

Résumé Dans la peau, il a été montré que Notch1 induit l'arrêt de la prolifération et la différentiation des keratinocytes. L'inactivation de Notch1 cause une hyperplasie de l'épiderme et la formation de carcinomes basaux cellulaires. Notre groupe a principalement identifié deux voies de signalisations, la voie Shh et la voie Wnt, qui sont dérégulées en conséquence de l'inactivation de Notch1 dans la peau. Nous avons démontré l'habilité de Notch1 à réprimer la voie Wnt induite par ß-catenin dans les keratinocytes primaires ainsi que dans d'autres types de cellules épithéliales humaines. De plus, nous avons pu déterminer que Notch1 régule cette voie, probablement en favorisant la phosphorylation de ß-catenin par le complexe axin/APC/GSK-3ß. La protéine faisant partie de la voie Wnt, ou la protéine affectant la voie Wnt, qui est régulée par Notch1 est sujette à de plus amples investigations. Un autre but de cette étude a été l'identification de potentiels gènes cibles de Notch1 autres que ceux faisant partie des voies de signalisation Shh et Wnt précédemment évoquées. Ce projet fut abordé par l'analyse de puces à ADN (ISREC et Affymetrix) qui ont été utilisées pour des expériences de gain et de perte de fonction de Notch1 dans des keratinocytes prúmaires. En plus de l'hyperplasie épidermale, les souris Notch1 déficiente ont une perte importante de poils. Nous avons montré que Notch1 est nécessaire pour le développement et l'homéostasie des follicules pileux. En effet, l'inactivation du gène Notch1 mediée par l'activation des kératines 5 ou 14 dans l'épiderme, cause des défauts du cycle ainsi que de la structure des poils. De plus, d'autres appendices de la peau, comme les glandes sudoripares et de Meibomius, ont une structure anormale et sont non fonctionnelles dans les souris Notch1 déficiente. Finalement, nous avons observé que la déficience de Notch1 dans l'épithélium cornéen mène à la formation d'une plaque épidermale opaque sur la cornée. Basé sur l'hypothèse que le défaut des glandes de Meibomius des souris Notch1 déficientes cause des lésions de la surface oculaire, nous avons montré que Notch1 est essentiel pour la cicatrisation de la cornée. Lorsque Notch1 est absent, les cellules souches de l'épithélium cornéen ne sont plus capables de se différentier en cellules cornéennes, mais réparent la blessure en se différentiant en épiderme. Ce résultat indique que Notch1 est essentiel pour la différentiation de cellules souches de la cornée qui sont spécifiquement impliquées dans la réparation de la cornée. De plus, nous avons montré que l'expression de CRBP1 dans l'épithélium cornéen est diminuée en l'absence de Notch1, ceci étant possiblement à l'origine de la formation de la plaque épidermale. Abstract: In the skin, Notch1 has been shown to trigger cell growth arrest and differentiation of keratinocytes. Notch1 inactivation results in epidermal hyperplasia and subsequent formation of basal cell carcinoma-like (BCC-like) tumors. So far our group has identified two main pathways, the Shh and the Wnt pathway, that are deregulated as a consequence of Notch1 inactivation in the skin. We showed the ability of Notch1 to represses ß-catenin-mediated Wnt signaling in primary keratinocytes as well as in other types of human epithelial cells. In addition we were able to determine that Notch1 regulates this pathway possibly by enhancing ß-catenin phosphorylation by the axin/APC/GSK-3ß complex. The exact target protein of the Wnt pathway or target protein that affects the Wnt pathway, and that is regulated by Notch1, is subject of current investigation. Another aim of this study was the identification of possible Notch1 target genes in addition to those of the Shh and Wnt signaling pathways. This was addressed by gene chip analysis using ISREC as well as Affymetrix microarrays for gain and loss of function of Notch1 in mouse primary keratinocytes. In addition to epidermal hyperplasia, Notch1 deficient mice show an important hair loss. We showed that Notch1 is required for postnatal development and homeostasis of hair follicles. Indeed, keratin5 or keratinl4-driven Cre recombinase-mediated inactivation of the Notch1 gene in the epidermis causes perturbations of the hair cycle and structural defects of the hair follicle. Moreover, other skin appendages, like the sweat and Meibomian glands show abnormal morphology and are not functional in the Notch 1 deficient mice. Finally, we observed that Notch1 deficiency in the corneal epithelium leads to the formation of an epidermal corneal plaque. Based on the hypothesis that the Meiboinian gland defect in the Notch1 deficient mice results in lesions of the eye surface, we showed that Notch1 is essential for wound-healing of the cornea. In absence of Notch1 the stem cells of the corneal epithelium are no longer able to differentiate in the corneal fate but instead repair the wound by differentiating into skin-like epidermis. This result indicated that Notch1 is essential for the differentiation of corneal stem cells specifically implicated in corneal wound-healing. Moreover, we showed that CRBP1 expression in the corneal epithelium was lost in the absence of Notch1, possibly being at the origin of plaque formation.

Role of CD8 in aberrant function of cytotoxic T lymphocytes.

Using H-2Kd-restricted photoprobe-specific cytotoxic T lymphocyte (CTL) clones, which permit assessment of T cell receptor (TCR)-ligand interactions by TCR photoaffinity labeling, we observed that the efficiency of antigen recognition by CTL was critically dependent on the half-life of TCR-ligand complexes. We show here that antigen recognition by CTL is essentially determined by the frequency of serial TCR engagement, except for very rapid dissociations, which resulted in aberrant TCR signaling and antagonism. Thus agonists that were efficiently recognized exhibited rapid TCR-ligand complex dissociation, and hence a high frequency of serial TCR engagement, whereas the opposite was true for weak agonists. Surprisingly, these differences were largely accounted for by the coreceptor CD8. While it was known that CD8 substantially decreases TCR-ligand complex dissociation, we observed in this study that this effect varied considerably among ligand variants, indicating that epitope modifications can alter the CD8 contribution to TCR-ligand binding, and hence the efficiency of antigen recognition by CTL.

Consistency and population sensitivity properties in marriage and Rrommate markets

We consider one-to-one matching markets in which agents can either be matched as pairs or remain single. In these so-called roommate markets agents are consumers and resources at the same time. Klaus (Games Econ Behav 72:172-186, 2011) introduced two new "population sensitivity" properties that capture the effect newcomers have on incumbent agents: competition sensitivity and resource sensitivity. On various roommate market domains (marriage markets, no-odd-rings roommate markets, solvable roommate markets),we characterize the core using either of the population sensitivity properties in addition to weak unanimity and consistency. On the domain of all roommate markets, we obtain two associated impossibility results.

Acid-sensing channels in human bladder: expression, function and alterations during bladder pain syndrome.

Purpose: To examine the possible role of H+-activated acid-sensing ion channels (ASICs) in pain perception we characterized their expression in bladder dome biopsies of Bladder Pain Syndrome (BPS) patients and controls, in cultured human urothelium and in urothelial TEU-2 cells.Materials and Methods: Cold cut biopsies from the bladder dome were obtained in 8 asymptomatic controls and 28 patients with symptoms of BPS. ASIC expression was analyzed by QPCR and immunofluorescence. The channel function was measured by electrophysiology.Results: ASIC1a, ASIC2a and ASIC3 mRNAs were detected in human bladder. Similar amounts of ASIC1a and -3 were detected in detrusor smooth muscle, whereas in urothelium ASIC3 levels were higher than -1a. ASIC2a mRNA levels were lower than either -1a or -3 in both layers. ASIC currents were measured in TEU-2 cells and in primary cultures of human urothelium, and ASIC expression was confirmed by QPCR. Differentiation of TEU-2 cells caused an up-regulation of ASIC2a and ASIC3, and a down-regulation of ASIC1a mRNAs. BPS patients showed an up-regulation of ASIC2a and -3 mRNA, whereas ASIC1a remained unchanged. In contrast, the mRNA levels of TRPV1 were down-regulated during BPS. All differences were statistically significant (p<0.05)Conclusions: Several different ASIC subunits are expressed in human bladder and TEU-2 cells, where their levels are regulated during urothelial differentiation. An up-regulation of ASIC2a and -3 in BPS suggests their involvement in increased pain and hyperalgesia. A down-regulation of TRPV1 mRNA levels might indicate a different regulatory mechanism, controlling its expression in human bladder.

Comparative socio-economic evaluation of IBD patients with and without infliximab maintenance therapy

Background: The anti-TNFα agent Infliximab (IFX) is used for the treatment of moderate to severe inflammatory bowel disease (IBD) with insufficient response to conventional immunomodulator therapy. IFX maintenance therapy is expensive and it is unknown if indirect costs (eg. by loss of work productivity) can be reduced by this therapy. Goal: to evaluate the direct and indirect costs of an IBD patient cohort under maintenance IFX compared to a cohort under "conventional" immunomodulator therapy. Methods: Direct and indirect costs of an IBD cohort under IFX and a reference cohort (similar disease activity and location) under conventional immunomodulator therapy (Azathioprine, or 6-MP, or MTX) were retrospectively evaluated over 12 months (January to December 2008). Results: 54 IFX-patients (24f/30m, 37 CD, 10 UC, 7 IC) and 71 non-IFX-patients (38f/33m, 56 CD, 12 UC, 3 IC) were included. IFX patients were younger than non-IFX patients (36 vs. 47 years, P = 0.0003). The mean duration of inpatient stay in hospital (23 in IFX vs. 21 days for non-IFX, P = 0.909) and the hospitalization costs (7,692 in IFX vs. 4,179 SFr for non-IFX, P = 0.4540) did not differ. IFX-patients had significantly more frequently specialist outpatient consultations (8 vs. 4, P < 0.001) and outpatient-related costs (3,633 vs. 2,186 SFr, P <0.001). Total costs for all diagnostic procedures (blood work, endoscopies, radiology) were higher in the IFXcohort (2,265 vs. 1,164 SFr, P < 0.001). Sixty-five percent of IFX-patients had a 100% job employment compared to 80% in the non-IFX cohort (P = 0.001). Conclusions: The direct and indirect costs of maintenance IFX-treated IBD patients are higher compared to IBD patients under conventional immunomodulators. Care should be taken not only to judge the costs as the IFX treated population may represent a cohort with more aggressive disease phenotype, furthermore, quality of life aspects were not assessed.

Stable one-step technetium-99m labeling of His-tagged recombinant proteins with a novel Tc(I)-carbonyl complex.

We have developed a technetium labeling technology based on a new organometallic chemistry, which involves simple mixing of the novel reagent, a 99m Tc(I)-carbonyl compound, with a His-tagged recombinant protein. This method obviates the labeling of unpaired engineered cysteines, which frequently create problems in large-scale expression and storage of disulfide-containing proteins. In this study, we labeled antibody single-chain Fv fragments to high specific activities (90 mCi/mg), and the label was very stable to serum and all other challenges tested. The pharmacokinetic characteristics were indistinguishable from iodinated scFv fragments, and thus scFV fragments labeled by the new method will be suitable for biodistribution studies. This novel labeling method should be applicable not only to diagnostic imaging with 99mTc, but also to radioimmunotherapy approaches with 186/188 Re, and its use can be easily extended to almost any recombinant protein or synthetic peptide.