Qualitative and quantitative analysis of thalamo-cortical axons in the somatosensory cortex of normal and barrelless mice

Résumé Les rongeurs utilisent leurs moustaches (vibrisses) pour explorer le milieu environnant. Chaque moustache est mue par un système des muscles. Les récepteurs situés à sa base transmettent les informations au système nerveux central. La transmission vers l'écorce se fait via trois neurones de relais qui se trouvent au niveau du ganglion trigéminé, du tronc cérébral et du thalamus. La représentation corticale d'une vibrisse est une concentration des axones thalamo-corticaux (ATC) autour desquelles s'organisent leurs cibles, les cellules de la couche IV. La structure peut être identifiée histologiquement en coupes tangentielles et porte le nom de « barrel » (« tonneau »). Cette correspondance vibrisse - barrel fait de ce système un model idéal pour étudier l'influence de l'activité périphérique sur l'établissement et le maintien des cartes somatotopiques. Notre laboratoire dispose d'une souche de souris qui a subi une mutation spontanée pour le gène codant l'adenylyl cyclase I (ACI). Cette enzyme membranaire catalyse la formation de l'AMPc et joue un rôle important dans le guidage axonal, la libération des neurotransmetteurs et l'intégration des signaux postsynaptiques. Nous avons démontré dans un premier temps que cette souris adulte ne développe pas de barrels. Cela est dû à un manque d'organisation des ATC et aussi des cellules de la couche IV. De plus, les résultats électrophysiologiques montrent que les informations venant des vibrisses adjacentes ne sont pas intégrées d'une manière normale. Dans ce travail de thèse, j'ai analysé la morphologie des ATC révélés individuellement avec de la biocytine. L'analyse quantitative des ATC a mis en évidence les points suivants: 1. Les axones de la souris normale (NOR) quittent le thalamus, traversent la capsule interne et la substance blanche sous-corticale et pénètrent dans le cortex somato-sensoriel primaire. A l'intérieur de l'écorce ils traversent au maximum 3 colonnes corticales adjacentes dont une contient le barrel cible. En passant à travers les couches VI et V, ces axones arborisent et convergent progressivement vers le barrel dans lequel ils forment une riche arborisation. Un petit nombre des branches « errantes », pleines de boutons synaptiques, pénètrent dans les barrels voisins. Deux axones NOR provenant de corps cellulaires très proches dans le thalamus peuvent avoir un cheminement très divergent lors de la traversée de la capsule interne et de la substance blanche sous-corticale mais, à leur entrée dans le cortex, ils sont distants d'au maximum 2 colonnes corticales de la colonne qui contient le barrel cible et ils convergent progressivement vers ce barrel. 2. Les axones de la souris mutante (BRL) ont le même trajet sous-cortical que les axones NOR, mais leur entrée dans le cortex somato-sensoriel primaire est aléatoire. A l'interface entre la substance blanche sous-corticale et le cortex, l'axone principal se divise rapidement en troncs axonaux qui traversent les couches VI et V d'une manière divergente pour arriver dans la couche IV. Cela contraste beaucoup avec la trajectoire des NOR qui convergent graduellement vers leur barrel cible. Le nombre de branches radiales que les axones BRL utilisent pour entrer dans le cortex et dans la couche IV est double par rapport aux axones NOR. Parmi ces branches, seules quelques-unes donnent des arborisations, les autres ne sont pas développées et leur morphologie est semblable à celle des branches formées par les axones de la souris normale lors du développement. Deux axones BRL issus de corps cellulaires proches dans le thalamus peuvent avoir une trajectoire très divergente jusqu'à leur entrée dans la couche IV, mais à ce niveau ils sont réorientés pour se retrouver et faire un nombre maximal de branches et boutons synaptiques dans la même région corticale. Dans un cas extrême, un des axones observés est entré dans le cortex à la limite entre l'aire somatosensorielle primaire et secondaire et a parcouru une distance de 2 mm pour retrouver son partenaire thalamique et donner avec celui-ci un nombre maximal de branches dans la même région de la couche IV. 3. Les mesures quantitatives ont montré que les arborisations corticales des axones NOR ont une longueur moyenne de 18mm et sont formées par 200 segments qui portent 1200 boutons synaptiques. Par rapport à la souris NOR, les axones BRL ont en moyenne la même longueur, le même nombre de segments et boutons synaptiques, mais donnent deux fois plus de branches radiales. La surface tangentielle occupée par les arborisations BRL dans la couche IV est 2 fois plus grande que celle des NOR. Cela signifie que les 1000 boutons synaptiques qui caractérisent les arborisations NOR et BRL dans la couche IV sont disséminés sur une surface tangentielle double chez les derniers, et donc que la densité des boutons par unité de surface corticale est en moyenne plus faible. En effet, l'augmentation de la surface corticale tangentielle des BRL est due aux surfaces de faible et moyenne densité synaptique (0 - 8 boutons / 400pn2) qui augmentent 2 fois tandis que les surfaces de haute densité synaptiques (8 - 64 boutons / 4001.tm2) sont les mêmes. Nous émettons l'hypothèse selon laquelle, durant le développement, les ATC de la souris BRL divergent et forment un nombre exubérant de branches. Grâce à cette divergence et aux branches supranuméraires, ils trouvent l'endroit de l'écorce où se trouvent leurs voisins thalamiques et arborisent abondamment dans cette région. Cependant, le déficit en AGI ne leurs permet pas par la suite, sous influence de l'activité périphérique, de retirer les branches qui se trouvent dans les endroits inappropriés de l'écorce, avec de possibles conséquences sur la discrimination tactile.

Epibulbar osseous choristomaa clinicopathological case series and review of the literature

Background:¦Choristomas are benign, congenital tumours composed of normal tissue in an¦abnormal location. Osseous choristomas represent the rarest form of epibulbar choristomas,¦with now 65 cases reported in the literature. We did a retrospective clinicopathological study¦of all patients with epibulbar osseous choristoma observed at our institution since 1982 and¦updated the last review of the literature.¦History and Signs:¦Three Caucasian male patients, aged between 3 months and 11 years,¦were identified. All osseous choristomas were located under the superotemporal bulbar¦conjunctiva of the right eye.¦Therapy and Outcome:¦All lesions were managed with surgical excision. Histopathology¦revealed the presence of lamellar bone in all cases, one of which was associated with a¦dermolipoma.¦Conclusions:¦We report a small rare case series of 3 epibulbar osseous choristomas and did a¦review of the literature. In one patient, the osteoma was associated with a dermolipoma,¦corresponding to the fourth reported complex choristoma of this type, in an otherwise normal¦eye, in the literature.

Macular and retinal dysfunction of unknown origin in adults with normal fundi: evidence for an autoimmune pathophysiology.

Here we report the discovery of and phenotypic characterization of a retinal disorder of unknown origin in adults using clinical, electrophysiological and psychophysical techniques, and to seek the presence of circulating retinal autoantibodies in the sera of these patients. Sixteen patients were identified with progressive bilateral visual loss over a period of months. Ten of the patients were male, and the average age was 55.3 years (range from 43 to 76 years). Known causes such as carcinoma-associated retinopathy, acute zonal occult outer retinopathy and hereditary cone dystrophy appeared unlikely. Investigations included electrophysiology, fundus autofluorescence imaging and psychophysical tests. The sera of these patients were analyzed with indirect immunocytochemistry and Western immunoblot analysis on murine (BALB/c) retinal tissue for the presence of retinal autoantibodies. Bilateral visual loss and photophobia progressed over a period of months to years (average 28.7 months, range 3-67) and subsequently stabilized. No abnormality was observed by biomicroscopy, angiography or autofluorescence imaging. Electrophysiology indicated predominant cone-system dysfunction, either macular or generalized, and post-phototransduction involvement in 9 patients (56%). Photopic and scotopic visual fields and dark adaptation kinetics showed both cone and rod system involvement in all cases. Heterogeneous immunohistochemical staining patterns were seen with the sera of these patients as compared with controls. A majority of the affected patients (9/15) stained with an antinuclear pattern. The retinal autoantibodies from the sera of most patients reacted with the retinal proteins of molecular weight between 34 and 40 kDa. The aetiology of this distinctive retinal disorder therefore appears to be mediated through an autoimmune mechanism.

Prevalence of normal weight obesity in Switzerland: effect of various definitions

BACKGROUND: Normal weight obesity (NWO) is defined as an excessive body fat associated with a normal body mass index (BMI < 25 kg/m(2)), but its prevalence in the general population is unknown. AIM OF THE STUDY: To assess the prevalence of NWO in Switzerland according to different cut points used to define excess body fat. METHODS: Cross-sectional study including 3,213 women and 2,912 men aged 35-75 years. Body fat was assessed by bioelectrical impedance analysis and prevalence of NWO was assessed using four previously published definitions for excess body fat. RESULTS: Percent body fat increased with age: in men, the values (mean +/- SD) were 20.2 +/- 5.4, 23.0 +/- 5.4, 26.3 +/- 5.2 and 28.2 +/- 4.6 for age groups 35-44, 45-54, 55-64 and 65-75 years, respectively; the corresponding values for women were 29.9 +/- 7.8, 33.1 +/- 7.4, 36.7 +/- 7.5 and 39.6 +/- 6.9. In men, prevalence of NWO was <1% irrespective of the definition used. Conversely, in women, a 1- to 20-fold difference (from 1.4 to 27.8%) in NWO prevalence was found. The prevalence of NWO increased with age when age-independent cut points were used in women, but not in men. CONCLUSIONS: Prevalence of NWO is low in the general population and higher in women than in men. The prevalence is highly dependent on the criteria used to define excess body fat, namely in women. The use of gender- and age-specific cut points to define excess body fat is better than fixed or gender-specific only cut points.

Normal pathogen-specific immune responses mounted by CTLA-4-deficient T cells: a paradigm reconsidered.

CTLA-4 is a critical negative regulator of T cell responses and CTLA-4-deficient (CTLA-4(-/-)) mice die of a lymphproliferative disease. Nevertheless, RAG-2-deficient mice reconstituted with a mixture of CTLA-4(-/-) and normal (CTLA-4(+/+)) bone marrow survive in the absence of any signs of disease, although 50% of their T cells do not express CTLA-4. Using such mixed chimeras, we analyzed the role of CTLA-4 in specific T cell responses to lymphocytic choriomeningitis virus, Leishmania major and mouse mammary tumor virus, which cause acute, chronic and persistent infections, respectively. The populations of antigen-specific CTLA-4(-/-)CD4(+) and CTLA-4(-/-)CD8(+) T cells became activated, expanded and contracted indistinguishably from CTLA-4(+/+)CD4(+) and CTLA-4(+/+)CD8(+) T cells after infection with all three pathogens. Thus, CTLA-4 is not involved in the down-regulation of specific T cell responses and peripheral deletion in a T cell-autonomous fashion.

Unilateral optic disc edema following trabeculectomy.

Two cases of a benign form of optic disc edema after successful trabeculectomy are reported. In both patients, optic disc edema was noted 2 to 4 weeks after trabeculectomy. The edema occurred without loss of visual acuity or field. The absolute intraocular pressure and intracranial pressure were normal--that is, the edema was not a syndrome of hypotony or pseudotumor cerebri. However, both patients had intracranial pressure in the high-normal range. The decrease in intraocular pressure into the low normal range after trabeculectomy may have altered the intracranial pressure:intraocular pressure ratio at the lamina cribrosa enough to produce optic disc edema.

Increased titers of anti-Saccharomyces cerevisiae antibodies in Crohn's disease patients with reduced H-ficolin levels but normal MASP-2 activity.

BACKGROUND AND AIMS: Mannan-binding lectin (MBL) and ficolins are microbial pattern recognition molecules that activate the lectin pathway of complement. We previously reported the association of MBL deficiency with anti-Saccharomyces cerevisiae antibodies (ASCA) in patients with Crohn's disease (CD). However, ASCA are also frequently found in MBL-proficient CD patients. Here we addressed expression/function of ficolins and MBL-associated serine protease-2 (MASP-2) regarding potential association with ASCA. METHODS: ASCA titers and MBL, ficolin and MASP-2 concentrations were determined by ELISA in the serum of patients with CD, ulcerative colitis (UC), and in healthy controls. MASP-2 activity was determined by measuring complement C4b-fixation. Anti-MBL autoantibodies were detected by ELISA. RESULTS: In CD and UC patients, L-ficolin concentrations were significantly higher compared to healthy controls (p<0.001 and p=0.029). In contrast, H-ficolin concentrations were slightly reduced in CD and UC compared to healthy controls (p=0.037 for UC vs. hc). CD patients with high ASCA titers had significantly lower H-ficolin concentrations compared to ASCA-low/negative CD patients (p=0.009). However, MASP-2 activity was not different in ASCA-negative and ASCA-positive CD patients upon both, ficolin- or MBL-mediated MASP-2 activation. Finally, anti-MBL autoantibodies were not over-represented in MBL-proficient ASCA-positive CD patients. CONCLUSIONS: Our results suggest that low expression of H-ficolin may promote elevated ASCA titers in the ASCA-positive subgroup of CD patients. However, unlike MBL deficiency, we found no evidence for low expression of serum ficolins or reduced MASP-2 activity that may predispose to ASCA development.

P16 Mediated Suppression Of Telomerase In Normal And Malignant Human Breast Cells.

Summary The cyclin-dependent kinase inhibitor p16(INK4a) (CDKN2A) is an important tumor-suppressor gene frequently inactivated in human tumors. p16 suppresses the development of cancer by triggering an irreversible arrest of cell proliferation termed cellular senescence. Here, we describe another anti-oncogenic function of p16 in addition to its ability to halt cell cycle progression. We show that transient expression of p16 stably represses the hTERT gene, encoding the catalytic subunit of telomerase, in both normal and malignant breast epithelial cells. Short-term p16 expression increases the amount of histone H3 trimethylated on lysine 27 (H3K27) bound to the hTERT promoter, resulting in transcriptional silencing, likely mediated by polycomb complexes. Our results indicate that transient p16 exposure may prevent malignant progression in dividing cells by irreversible repression of genes, such as hTERT, whose activity is necessary for extensive self-renewal.

BRF1 mutations alter RNA polymerase III-dependent transcription and cause neurodevelopmental anomalies.

RNA polymerase III (Pol III) synthesizes tRNAs and other small noncoding RNAs to regulate protein synthesis. Dysregulation of Pol III transcription has been linked to cancer, and germline mutations in genes encoding Pol III subunits or tRNA processing factors cause neurogenetic disorders in humans, such as hypomyelinating leukodystrophies and pontocerebellar hypoplasia. Here we describe an autosomal recessive disorder characterized by cerebellar hypoplasia and intellectual disability, as well as facial dysmorphic features, short stature, microcephaly, and dental anomalies. Whole-exome sequencing revealed biallelic missense alterations of BRF1 in three families. In support of the pathogenic potential of the discovered alleles, suppression or CRISPR-mediated deletion of brf1 in zebrafish embryos recapitulated key neurodevelopmental phenotypes; in vivo complementation showed all four candidate mutations to be pathogenic in an apparent isoform-specific context. BRF1 associates with BDP1 and TBP to form the transcription factor IIIB (TFIIIB), which recruits Pol III to target genes. We show that disease-causing mutations reduce Brf1 occupancy at tRNA target genes in Saccharomyces cerevisiae and impair cell growth. Moreover, BRF1 mutations reduce Pol III-related transcription activity in vitro. Taken together, our data show that BRF1 mutations that reduce protein activity cause neurodevelopmental anomalies, suggesting that BRF1-mediated Pol III transcription is required for normal cerebellar and cognitive development.

Iron supplementation in a large Swiss Cohort of Inflammatory Bowel Disease patients demonstrates a shift form oral to intravenous therapy over time

Background and Aims: The 2007 European Crohn's and Colitis Organization guidelines on anemia in inflammatory bowel disease (IBD) favour intravenous (iv) over oral (po) iron supplementation due to better effectiveness and tolerance. We aimed to determine the percentage of IBD patients under iron supplementation therapy and the dynamics of prescription habits (iv versus po) over time. Methods: Helsana, a leading Swiss health insurance company provides coverage for approximately 18% of the Swiss population, corresponding to about 1.2 million enrollees. Patients with Crohn's disease (CD) and ulcerative colitis (UC) were analyzed from the anonymised Helsana database. Results: In total, 629 CD (61% female) and 398 UC (57% female) patients were identified, mean observation time was 31.8 months for CD and 31.0 months for UC patients. Of the entire study population, 27.1% were prescribed iron (21.1% in males and 31.1% in females). Patients treated with IBD-specific drugs (steroids, immunomodulators, anti-TNF agents) were more frequently treated with iron compared to patients without any medication (35.0% vs. 20.9%, OR 1.91, 95%-CI 1.41-2.61). The prescription of iv iron increased from 2006/2007 (48.8% of all patients receiving any iron priscription) to 65.2% in 2008/2009 by a factor of 1.89. Conclusions: One third of the IBD population was treated with iron supplementation. A gradual shift from oral to iv iron was observed over time. This switch in prescription habits goes along with the implementation of the ECCO consensus guidelines on anemia in IBD.

Structure and kinematics of the Jungfrau syncline, Faflertal (Valais, Alps), and its regional significance

The formation and structural evolution of the jungrau syncline is described, based on excellent outcrops occurring in the lotschental, in the central alps of switzerland. the quality of the outcrops allows us to demonstrate that the external massifs of the swiss alps have developed due to internal folding. The jungfrau suncline, which separates the autochtonous gastern dome from the aar massif basement gneiss folds, is composed of slivers of basement rocks with their mesozoic sedimentary cover. in the inner faflertal, a side valley of the lotschental, the 200 m thick syncline cp, roses fpir imots, the gastern massif with a reduced mesozoic sedimentary cover in a normal stratigraphic succession, two units of overturned basement rocks with their mesozoic sedimentary cover, and the overturned lower limn of the tschingelhorn gneiss fold of the aar massif with lenses of its sedimentary cover. stratigraphy shows that the lower units, related to the gastern massis, are condensed and that the upper units, deposited farther away from a gastern paleo-high, form a more complete sequence, linked to the doldenhorn meso-cneozoic basin fill. the integration of these local observations with published regional data leads to the following model. on the northern margin of the doldenhorn hbasin, at the northern fringe of the alpine tethuys, the pre-triassic crystalline basement and its mesozoic sedimentary cover were folded by ductile deformation at temperatures above 300 degrees C and in the presence of high fluid pressures, as the helveti c and penninic nappes were overthrusted towards the northwest during the main alpine deformation phase, the visosity contrast between the basement gneisses and the sediments caused the formation of large basement anticlines and tight sedimentary sunclines (mullion-type structures). The edges of basement blocks bounded buy pre-cursor se-dipping normal faults at the northwestern border of the doldenhorn basin were deformed bu simple shear, creating overturned slices of crystalline rocks with their sedimentary cover in what now forms the hungfrau syncline. the localisation of ductile deformation in the vicinity of pre-existing se-dipping faults is thought to have been helped by the circulation of fluids along the faults; these fluids would have been released from the mesozoic sediments by metamorphic dehydration reactions accompanied by creep and dynamic recrystallisation of quartz at temperatures above 300 degrees C. Quantification of the deformation suggests an strain ellipsoid with a ratio (1 + e(1)/+ e(3)) of approximately 1000. The jungfrau suncline was deformed bu more brittle nw-directed shear creating well-developed shear band cleavages at a late stage, after cooling by uplift and erosion. It is suggested that the external massifs of the apls are basement gneiss folds created at temperatures of 300 degrees C by detachment through ductile deformation of the upper crust of the european plate as it was underthrusted below the adriatic plate.

Catalogue des tableaux... ayant formé le cabinet du major Merighi... / [expert] Ferdinand Laneuville

[Vente. Art. 1858-05-15. Paris]

Catalogue de tableaux précieux... ayant formé le cabinet de M. R***,... [Rochard, Bruxelles] / [expert] Ferdinand Laneuville

[Vente. Art. 1858-12-13 - 1858-12-14. Paris]

Catalogue d'une remarquable réunion de 14 tableaux... ayant formé le cabinet de feu M. le chevalier W. J. Junius Van Hemert,... / [expert] Ferdinand Laneuville

[Vente. Art. 1859-04-18. Paris]