Storage and uptake of D-serine into astrocytic synaptic-like vesicles specify gliotransmission.

Glial cells are increasingly recognized as active players that profoundly influence neuronal synaptic transmission by specialized signaling pathways. In particular, astrocytes have been shown recently to release small molecules, such as the amino acids l-glutamate and d-serine as "gliotransmitters," which directly control the efficacy of adjacent synapses. However, it is still controversial whether gliotransmitters are released from a cytosolic pool or by Ca(2+)-dependent exocytosis from secretory vesicles, i.e., by a mechanism similar to the release of synaptic vesicles in synapses. Here we report that rat cortical astrocytes contain storage vesicles that display morphological and biochemical features similar to neuronal synaptic vesicles. These vesicles share some, but not all, membrane proteins with synaptic vesicles, including the SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) synaptobrevin 2, and contain both l-glutamate and d-serine. Furthermore, they show uptake of l-glutamate and d-serine that is driven by a proton electrochemical gradient. d-Serine uptake is associated with vesicle acidification and is dependent on chloride. Whereas l-serine is not transported, serine racemase, the synthesizing enzyme for d-serine, is anchored to the membrane of the vesicles, allowing local generation of d-serine. Finally, we reveal a previously unexpected mutual vesicular synergy between d-serine and l-glutamate filling in glia vesicles. We conclude that astrocytes contain vesicles capable of storing and releasing d-serine, l-glutamate, and most likely other neuromodulators in an activity-dependent manner.

Importation of Acinetobacter baumannii into a burn unit: a recurrent outbreak of infection associated with widespread environmental contamination.

A burn patient was infected with Acinetobacter baumannii on transfer to the hospital after a terrorist attack. Two patients experienced cross-infection. Environmental swab samples were negative for A. baumannii. Six months later, the bacteria reemerged in 6 patients. Environmental swab samples obtained at this time were inoculated into a minimal mineral broth, and culture results showed widespread contamination. No case of infection occurred after closure of the unit for disinfection.

Normal kinetics of intestinal glucose absorption in the absence of GLUT2: evidence for a transport pathway requiring glucose phosphorylation and transfer into the endoplasmic reticulum.

Glucose is absorbed through the intestine by a transepithelial transport system initiated at the apical membrane by the cotransporter SGLT-1; intracellular glucose is then assumed to diffuse across the basolateral membrane through GLUT2. Here, we evaluated the impact of GLUT2 gene inactivation on this transepithelial transport process. We report that the kinetics of transepithelial glucose transport, as assessed in oral glucose tolerance tests, was identical in the presence or absence of GLUT2; that the transport was transcellular because it could be inhibited by the SGLT-1 inhibitor phlorizin, and that it could not be explained by overexpression of another known glucose transporter. By using an isolated intestine perfusion system, we demonstrated that the rate of transepithelial transport was similar in control and GLUT2(-/-) intestine and that it was increased to the same extent by cAMP in both situations. However, in the absence, but not in the presence, of GLUT2, the transport was inhibited dose-dependently by the glucose-6-phosphate translocase inhibitor S4048. Furthermore, whereas transport of [(14)C]glucose proceeded with the same kinetics in control and GLUT2(-/-) intestine, [(14)C]3-O-methylglucose was transported in intestine of control but not of mutant mice. Together our data demonstrate the existence of a transepithelial glucose transport system in GLUT2(-/-) intestine that requires glucose phosphorylation and transfer of glucose-6-phosphate into the endoplasmic reticulum. Glucose may then be released out of the cells by a membrane traffic-based pathway similar to the one we previously described in GLUT2-null hepatocytes.

Esophagogastric cancer: integration of targeted therapies into systemic chemotherapy.

Although combination chemotherapy has been shown to be more effective than single agents in advanced esophagogastric cancer, the better response rates have not fulfilled their promise as overall survival times from best combination still range between 8 to 11 months. So far, the development of targeted therapies stays somewhat behind their integration into treatment concepts compared to other gastrointestinal diseases. Thus, the review summarizes the recent advances in the development of targeted therapies in advanced esophagogastric cancer. The majority of agents tested were angiogenesis inhibitors or agents targeting the epidermal growth factor receptors EGFR1 and HER2. For trastuzumab and bevacizumab, phase III trial results have been presented recently. While addition of trastuzumab to cisplatin/5-fluoropyrimidine-based chemotherapy results in a clinically relevant and statistically significant survival benefit in HER 2+ patients, the benefit of the addition of bevacizumab to chemotherapy was not significant. Thus, all patients with metastatic disease should be tested for HER-2 status in the tumor. Trastuzumab in combination with cisplatin/5-fluoropyrimidine-based chemotherapy is the new standard of care for patients with HER2-positive advanced gastric cancer.

Binding of d-methadone, l-methadone, and dl-methadone to proteins in plasma of healthy volunteers: role of the variants of alpha 1-acid glycoprotein.

The plasma concentrations of alpha 1-acid glycoprotein (AAG), albumin, triglycerides, cholesterol, and total proteins, as well as the plasma binding of racemic, d-methadone, and l-methadone were measured in 45 healthy subjects. The AAG phenotypes and the concentrations of AAG variants were also determined. The measured free fractions for racemic, d-methadone, and l-methadone were, respectively, 12.7% +/- 3.3%, 10.0% +/- 2.9%, and 14.2% +/- 3.2% (mean +/- SD). A significant correlation was obtained between the binding ratio (B/F) for dl-methadone and the total AAG concentration (r = 0.724; p less than 0.001). A multiple stepwise regression analysis showed that AAG was the main explanatory variable for the binding of the racemate. When concentrations of AAG variants were considered, a significant correlation was obtained between the binding ratio of dl-methadone and orosomucoid2 A concentration (r = 0.715; p less than 0.001), a weak correlation between dl-methadone and orosomucoid1 S concentration (r = 0.494; p less than 0.001), and no correlation between dl-methadone and orosomucoid1 F1 concentration (r = 0.049; not significant). Similar findings were obtained with the enantiomers. This study shows the importance of considering not only total AAG but also concentrations of AAG variants when measuring the binding of methadone and possibly of other drugs in plasma.

Differentiation of postmitotic neuroblasts into substance P-immunoreactive sensory neurons in dissociated cultures of chick dorsal root ganglion.

Counts performed on dissociated cell cultures of E10 chick embryo dorsal root ganglia (DRG) showed after 4-6 days of culture a pronounced decline of the neuronal population in neuron-enriched cultures and a net gain in the number of ganglion cells in mixed DRG cell cultures (containing both neurons and nonneuronal cells). In the latter case, the increase in the number of neurons was found to depend on NGF and to average 119% in defined medium or 129% in horse serum-supplemented medium after 6 days of culture. The lack of [3H]thymidine incorporation into the neuronal population indicated that the newly formed ganglion cells were not generated by proliferation. On the contrary, the differentiation of postmitotic neuroblasts present in the nonneuronal cell compartment was supported by sequential microphotographs of selected fields taken every hour for 48-55 hr after 3 days of culture. Apparently nonneuronal flat dark cells exhibited morphological changes and gradually evolved into neuronal ovoid and refringent cell bodies with expanding neurites. The ultrastructural organization of these evolving cells corresponded to that of primitive or intermediate neuroblasts. The neuronal nature of these rounding up cell bodies was indeed confirmed by the progressive expression of various neuronal cell markers (150 and 200-kDa neurofilament triplets, neuron specific enolase, and D2/N-CAM). Besides a constant lack of immunoreactivity for tyrosine hydroxylase, somatostatin, parvalbumin, and calbindin-D 28K and a lack of cytoenzymatic activity for carbonic anhydrase, all the newly produced neurons expressed three main phenotypic characteristics: a small cell body, a strong immunoreactivity to MAG, and substance P. Hence, ganglion cells newly differentiated in culture would meet characteristics ascribed to small B sensory neurons and more specifically to a subpopulation of ganglion cells containing substance P-immunoreactive material.

Comparison of in-hospital mortality for acute myocardial infarction in Switzerland with admission during routine duty hours versus admission during out of hours (insight into the AMIS plus registry).

To improve long-term survival, prompt revascularization of the infarct-related artery should be done in patients with acute myocardial infarction (AMI); therefore, a large proportion of these patients would be hospitalized during out of hours. The clinical effects of out-of-hours AMI management were already questioned, with conflicting results. The purpose of this investigation was to compare the in-hospital outcome of patients admitted for AMI during out of hours and working hours. All patients with AMI included in the AMIS Plus Registry from January 1, 1997, to March 30, 2006, were analyzed. The working-hours group included patients admitted from 7 a.m. to 7 p.m. on weekdays, and the out-of-hours group included patients admitted from 7 p.m. to 7 a.m. on weekdays or weekends. Major cardiac events were defined as cardiovascular death, reinfarction, and stroke. The study primary end points were in-hospital death and major adverse cardiac event (MACE) rates. A total of 12,480 patients met the inclusion criteria, with 52% admitted during normal working hours, and 48%, during out of hours. Patients admitted during weekdays included more women (28.1% vs 26%; p = 0.009), older patients (65.5 +/- 13 vs 64.1 +/- 13 years; p = 0.0011), less current smokers (40.1% vs 43.5%; p <0.001), and less patients with a history of ischemic heart disease (31.5% vs 34.5%; p = 0.001). A significantly higher proportion of patients admitted during out of hours had Killip's class III and IV. No differences in terms of in-hospital survival rates between the 2 groups (91.5% vs 91.2%; p = 0.633) or MACE-free survival rates (both 88.5%; p = 1.000) were noted. In conclusion, the outcome of patients with AMI admitted out of hours was the same compared with those with a weekday admission. Of predictors for in-hospital outcome, timing of admission had no significant influence on mortality and/or MACE incidence.

Light-induced degradation of phyA is promoted by transfer of the photoreceptor into the nucleus.

Higher plants possess multiple members of the phytochrome family of red, far-red light sensors to modulate plant growth and development according to competition from neighbors. The phytochrome family is composed of the light-labile phyA and several light-stable members (phyB-phyE in Arabidopsis). phyA accumulates to high levels in etiolated seedlings and is essential for young seedling establishment under a dense canopy. In photosynthetically active seedlings high levels of phyA counteract the shade avoidance response. phyA levels are maintained low in light-grown plants by a combination of light-dependent repression of PHYA transcription and light-induced proteasome-mediated degradation of the activated photoreceptor. Light-activated phyA is transported from the cytoplasm where it resides in darkness to the nucleus where it is needed for most phytochrome-induced responses. Here we show that phyA is degraded by a proteasome-dependent mechanism both in the cytoplasm and the nucleus. However, phyA degradation is significantly slower in the cytoplasm than in the nucleus. In the nucleus phyA is degraded in a proteasome-dependent mechanism even in its inactive Pr (red light absorbing) form, preventing the accumulation of high levels of nuclear phyA in darkness. Thus, light-induced degradation of phyA is in part controlled by a light-regulated import into the nucleus where the turnover is faster. Although most phyA responses require nuclear phyA it might be useful to maintain phyA in the cytoplasm in its inactive form to allow accumulation of high levels of the light sensor in etiolated seedlings.

The E3-Ubiquitin Ligase TRIM50 Interacts with HDAC6 and p62, and Promotes the Sequestration and Clearance of Ubiquitinated Proteins into the Aggresome.

In this study we report that, in response to proteasome inhibition, the E3-Ubiquitin ligase TRIM50 localizes to and promotes the recruitment and aggregation of polyubiquitinated proteins to the aggresome. Using Hdac6-deficient mouse embryo fibroblasts (MEF) we show that this localization is mediated by the histone deacetylase 6, HDAC6. Whereas Trim50-deficient MEFs allow pinpointing that the TRIM50 ubiquitin-ligase regulates the clearance of polyubiquitinated proteins localized to the aggresome. Finally we demonstrate that TRIM50 colocalizes, interacts with and increases the level of p62, a multifunctional adaptor protein implicated in various cellular processes including the autophagy clearance of polyubiquitinated protein aggregates. We speculate that when the proteasome activity is impaired, TRIM50 fails to drive its substrates to the proteasome-mediated degradation, and promotes their storage in the aggresome for successive clearance.

Integration of teacher education into the Swiss higher education system

The integration of specific institutions for teacher education into the higher education system represents a milestone in the Swiss educational policy and has broad implications. This thesis explores organizational and institutional change resulting from this policy reform, and attempts to assess structural change in terms of differentiation and convergence within the system of higher education. Key issues that are dealt with are, on the one hand, the adoption of a research function by the newly conceptualized institutions of teacher education, and on the other, the positioning of the new institutions within the higher education system. Drawing on actor-centred approaches to differentiation, this dissertation discusses system-level specificities of tertiarized teacher education and asks how this affects institutional configurations and actor constellations. On the basis of qualitative and quantitative empirical data, a comparative analysis has been carried out including case studies of four universities of teacher education as well as multivariate regression analysis of micro-level data on students' educational choices. The study finds that the process of system integration and adaption to the research function by the various institutions have unfolded differently depending on the institutional setting and the specific actor constellations. The new institutions have clearly made a strong push to position themselves as a new institutional type and to find their identity beyond the traditional binary divide which assigns the universities of teacher education to the college sector. Potential conflicts have been identified in divergent cognitive normative orientations and perceptions of researchers, teacher educators, policy-makers, teachers, and students as to the mission and role of the new type of higher education institution. - L'intégration dans le système d'enseignement supérieur d'institutions qui ont pour tâche spécifique de former des enseignants peut être considérée comme un événement majeur dans la politique éducative suisse, qui se trouve avoir des conséquences importantes à plusieurs niveaux. Cette thèse explore les changements organisationnels et institutionnels résultant de cette réforme politique, et elle se propose d'évaluer en termes de différentiation et de convergence les changements structurels intervenus dans le système d'éducation tertiaire. Les principaux aspects traités sont d'une part la nouvelle mission de recherche attribuée à ces institutions de formation pédagogique, et de l'autre la place par rapport aux autres institutions du système d'éducation tertiaire. Recourant à une approche centrée sur les acteurs pour étudier les processus de différen-tiation, la thèse met en lumière et en discussion les spécificités inhérentes au système tertiaire au sein duquel se joue la formation des enseignants nouvellement conçue et soulève la question des effets de cette nouvelle façon de former les enseignants sur les configurations institutionnelles et les constellations d'acteurs. Une analyse comparative a été réalisée sur la base de données qualitatives et quantitatives issues de quatre études de cas de hautes écoles pédagogiques et d'analyses de régression multiple de données de niveau micro concernant les choix de carrière des étudiants. Les résultats montrent à quel point le processus d'intégration dans le système et la nouvelle mission de recherche peuvent apparaître de manière différente selon le cadre institutionnel d'une école et la constellation spécifique des acteurs influents. A pu clairement être observée une forte aspiration des hautes écoles pédagogiques à se créer une identité au-delà de la structure binaire du système qui assigne la formation des enseignants au secteur des hautes écoles spéciali-sées. Des divergences apparaissent dans les conceptions et perceptions cognitives et normatives des cher-cheurs, formateurs, politiciens, enseignants et étudiants quant à la mission et au rôle de ce nouveau type de haute école. - Die Integration spezieller Institutionen für die Lehrerbildung ins Hochschulsystem stellt einen bedeutsamen Schritt mit weitreichenden Folgen in der Entwicklung des schweizerischen Bildungswesens dar. Diese Dissertation untersucht die mit der Neuerung verbundenen Veränderungen auf organisatorischer und institutioneller Ebene und versucht, die strukturelle Entwicklung unter den Gesichtspunkten von Differenzierung und Konvergenz innerhalb des tertiären Bildungssystems einzuordnen. Zentrale Themen sind dabei zum einen die Einführung von Forschung und Entwicklung als zusätzlichem Leistungsauftrag in der Lehrerbildung und zum andern die Positionierung der pädagogischen Hochschulen innerhalb des Hochschulsystems. Anhand akteurzentrierter Ansätze zur Differenzierung werden die Besonderheiten einer tertiarisierten Lehrerbildung hinsichtlich der Systemebenen diskutiert und Antworten auf die Frage gesucht, wie die Reform die institutionellen Konfigurationen und die Akteurkonstellationen beeinflusst. Auf der Grundlage qualitativer und quantitativer Daten wurde eine vergleichende Analyse durchgeführt, welche Fallstudien zu vier pädagogischen Hochschulen umfasst sowie Regressionsanalysen von Mikrodaten zur Studienwahl von Maturanden. Die Ergebnisse machen deutlich, dass sich der Prozess der Systemintegration und die Einführung von Forschung in die Lehrerbildung in Abhängigkeit von institutionellen Ordnungen und der jeweiligen Akteurkonstellation unterschiedlich gestalten. Es lässt sich bei den neu gegründeten pädagogischen Hochschulen ein starkes Bestreben feststellen, sich als neuen Hochschultypus zu positionieren und sich eine Identität zu schaffen jenseits der herkömmlichen binären Struktur, welche die pädagogischen Hochschulen dem Fachhochschul-Sektor zuordnet. Potentielle Konflikte zeichnen sich ab in den divergierenden kognitiven und normativen Orientierungen und Wahrnehmungen von Forschern, Ausbildern, Bildungspolitikern, Lehrern und Studierenden hinsichtlich des Auftrags und der Rolle dieses neuen Typs Hochschule.

Emplacement of ultramafic rocks into the continental crust monitored by light and other trace elements: An example from the Geisspfad body (Swiss-Italian Alps)

In order to evaluate the influence of continental crustal rocks on trace element budgets of serpentinized peridotites incorporated into the continental crust, we have analyzed the chemical composition of whole rock samples and minerals of the Geisspfad ultramafic complex (Swiss-Italian Alps). This complex represents a relict oceanic succession composed of serpentinites, ophicarbonates and metabasic rocks, emplaced into crustal gneisses during Alpine collision. Following peak metamorphic amphibolite facies conditions, fluid flow modified some of the trace element contents of ophicarbonates and deformed serpentinites close to the contact with country rocks. The fluid originated from the surrounding continental crustal rocks as documented by the increase of Pb in the serpentinites, and by the strongly negative all) values (-112 parts per thousand) of some ultramafic rocks close to the contact with surrounding gneisses. Little or no modification of the fluid mobile elements Li, B or U was observed in the serpentinite. In-situ analysis of light elements of serpentinite minerals indicate redistribution of light elements coupled to changes of mineral modes towards the outer 100-150 m of the massif. In the centre of the massif, Li is preferentially concentrated in olivine, while Be and B are hosted by tremolite. In contrast, at the outer rim of the massif, Li and Be are preferentially incorporated into diopside, and B into antigorite. This redistribution of light elements among the different minerals is visible in the serpentinite, at a maximum distance of -100-150 m from the ophicarbonate-metabasite contact. Our results show that interaction of ultramafic rocks and crust-derived fluids can be easily detected by studies of Pb and partial derivative D in whole rocks. We argue that small ultramafic bodies potentially record an emplacement-related trace element signature, and that crustal light element values in ultramafic rocks are not necessarily derived from a subducting slab. (C) 2008 Elsevier B.V. All rights reserved.

Vesicular transport of d-serine in astrocytes

The concept of tripartite synapse suggests that astrocytes make up a functional synapse with pre- and postsynaptic neuronal elements to modulate synaptic transmission through the regulated release of neuromodulators called gliotransmitters. Release of gliotransmitters such as glutamate or D-serine has been shown to depend on Ca21-dependent exocytosis. However, the origin (cytosolic versus vesicular) of the released gliotransmitter is still a matter of debate. The existence of Ca21-regulated exocytosis in astrocytes has been questioned mostly because the nature of secretory organelles which are loaded with gliotransmitters is unknown. Here we show the existence of a population of vesicles that uptakes and stores glutamate and D-serine in astrocytes which are present in situ. Immunoisolated glial organelles expressing synaptobrevin 2 (Sb2) display morphological and biochemical features very similar to synaptic vesicles. We demonstrate that these organelles not only contain and uptake glutamate but also display a glia-specific transport activity for D-serine. Furthermore, we report that the uptake of D-serine is energized by a H1-ATPase present on the immunoisolated vesicles and that cytosolic chloride ions modulate the uptake of D-serine. Finally, we show that serine racemase (SR), the synthesizing enzyme for D-serine, is anchored to the membrane of glial organelles allowing a local and efficient concentration of the gliotransmitter to be transported. We conclude that vesicles in astrocytes do exist with the goal to store and release D-serine, glutamate and most likely other neuromodulators.