Astrogliosis in epilepsy leads to overexpression of adenosine kinase, resulting in seizure aggravation

Adenosine kinase (ADK) is considered to be the key regulator of the brain's endogenous anticonvulsant, adenosine. In adult brain, ADK is primarily expressed in a subpopulation of astrocytes and striking upregulation of ADK in these cells has been associated with astrogliosis after kainic acid-induced status epilepticus (KASE) in the kainic acid mouse model of temporal lobe epilepsy. To investigate the causal relationship between KASE-induced astrogliosis, upregulation of ADK and seizure activity, we have developed a novel mouse model [the Adktm1−/−-Tg(UbiAdk) mouse] lacking the endogenous astrocytic enzyme due to a targeted disruption of the endogenous gene, but containing an Adk transgene under the control of a human ubiquitin promoter. Mutant Adktm1−/−-Tg(UbiAdk) mice were characterized by increased brain ADK activity and constitutive overexpression of transgenic ADK throughout the brain, with particularly high levels in hippocampal pyramidal neurons. This ADK overexpression was associated with increased baseline levels of locomotion. Most importantly, two-thirds of the mutant mice analysed exhibited spontaneous seizure activity in the hippocampus and cortex. This was the direct consequence of transgene expression, since this seizure activity could be prevented by systemic application of the ADK inhibitor 5-iodotubercidin. Intrahippocampal injection of kainate in the mutant mice resulted in astrogliosis to the same extent as that observed in wild-type mice despite the absence of endogenous astrocytic ADK. Therefore, KASE-induced upregulation of endogenous ADK in wild-type mice is a consequence of astrogliosis. However, seizures in kainic acid-injected mutants displayed increased intra-ictal spike frequency compared with wild-type mice, indicating that, once epilepsy is established, increased levels of ADK aggravate seizure severity. We therefore conclude that therapeutic strategies that augment the adenosine system after astrogliosis-induced upregulation of ADK constitute a neurochemical rationale for the prevention of seizures in epileps

Surface reactions of ethanol on UO2_2 thin film. Dehydrogenation and dehydration pathways

The reaction of ethanol has been investigated on a UO$_2$ thin film by temperature programmed desorption. Two channels for ethanol desorption are identified. The first, in the 250–500 K region, is coverage dependent while the second with a maximum peak temperature (T$_P$) at ca. 630 K is not. The desorption energy, Ed, of the second channel is found to be equal to ca. 150 kJ/mol with a prefactor of 10$^{12}$ s$^{-1}$ and a desorption order n - 2. This is attributed to surface ethoxides re-combinative desorption. This second desorption channel is accompanied by the desorption of acetaldehyde (and hydrogen) and ethylene (and water). Acetaldehyde (CH$_3$CHO) desorption, produced by the dehydrogenation of ethoxides, was sensitive to surface coverage. Its T$_P$ changed from 640 K at θ = 0.06 to 610 K at θ = 1, while ethylene (CH$_2$––CH$_2$) desorption Tp, produced by the dehydration of ethoxides did not shift. The molar ratio of these two products (CH$_3$CHO/CH$_2$––CH$_2$) of 0.8 is similar to that previously found on a UO$_2$ (1 1 1) single crystal and fits with the U–O bonding nature that contains a non-negligible fraction of covalency

Electronic structure and non-magnetic character of δ\delta-Pu-Am alloys

The {\em around-mean-field} LSDA+U correlated band theory is applied to investigate the electronic and magnetic structure of $fcc$-Pu-Am alloys. Despite a lattice expansion caused by the Am atoms, neither tendency to 5$f$ localization nor formation of local magnetic moments on Pu atoms in Pu-Am alloys are found. The $5f$-manifolds in the alloys are calculated being very similar to a simple weighted superposition of elemental Pu and Am $5f$-states

Synthesis of transuranium-based nanocrystals via the thermal decomposition of actinyl nitrates

In this communication, we report on the use of easily accessible actinide precursors to synthesize actinide oxide nanocrystals. Uranyl and neptunyl nitrates have been successfully used as starting materials in the non-aqueous synthesis of AnO2 (An = U, Np) nanocrystals. This communication reports for the first time on the formation of transuranium-based nanocrystals.JRC.E.5 - Nuclear chemistr

An Atomic-Scale Understanding of UO2 Surface Evolution During Anoxic Dissolution

Our present understanding of surface dissolution of nuclear fuels such as uranium dioxide (UO2) is limited by the use of non-local characterization techniques. Here we discuss the use of state-of-the-art scanning transmission electron microscopy (STEM) to reveal atomic–scale changes occurring to a UO2 thin film subjected to anoxic dissolution in deionised water. No amorphisation of the UO2 film surface during dissolution is observed, and dissolution occurs preferentially at surface reactive sites that present as surface pits which increase in size as the dissolution proceeds. Using a combination of STEM imaging modes, energy-dispersive X-ray spectroscopy (STEM-EDS), and electron energy loss spectroscopy (STEM-EELS), we investigate structural defects and oxygen passivation of the surface that originates from the filling of the octahedral interstitial site in the centre of the unit cells and its associated lattice contraction. Taken together, our results reveal complex pathways for both the dissolution and infiltration of solutions into UO2 surfaces

The importance of Real-Life research in Respiratory Medicine: Manifesto of the Respiratory Effectiveness Group:Endorsed by the International Primary Care Respiratory Group and the World Allergy Organization

status: publishe

Inventory of current EU paediatric vision and hearing screening programmes

Background: We examined the diversity in paediatric vision and hearing screening programmes in Europe. Methods: Themes relevant for comparison of screening programmes were derived from literature and used to compile three questionnaires on vision, hearing and public-health screening. Tests used, professions involved, age and frequency of testing seem to influence sensitivity, specificity and costs most. Questionnaires were sent to ophthalmologists, orthoptists, otolaryngologists and audiologists involved in paediatric screening in all EU fullmember, candidate and associate states. Answers were cross-checked. Results: Thirty-nine countries participated; 35 have a vision screening programme, 33 a nation-wide neonatal hearing screening programme. Visual acuity (VA) is measured in 35 countries, in 71% more than once. First measurement of VA varies from three to seven years of age, but is usually before the age of five. At age three and four picture charts, including Lea Hyvarinen are used most, in children over four Tumbling-E and Snellen. As first hearing screening test otoacoustic emission (OAE) is used most in healthy neonates, and auditory brainstem response (ABR) in premature newborns. The majority of hearing testing programmes are staged; children are referred after one to four abnormal tests. Vision screening is performed mostly by paediatricians, ophthalmologists or nurses. Funding is mostly by health insurance or state. Coverage was reported as >95% in half of countries, but reporting was often not first-hand. Conclusion: Largest differences were found in VA charts used (12), professions involved in vision screening (10), number of hearing screening tests before referral (1-4) and funding sources (8)

Electron Spectroscopy Study of Pu and Pu Compounds (invited talk)

see attachmentJRC.E.6-Actinides researc

Photoemission Study of the 5f Localization in Thin Films of Pu.

Abstract not availableJRC.E-Institute for Transuranium Elements (Karlsruhe

Thin Layers in Actinide Research.

Abstract not availableJRC.E-Institute for Transuranium Elements (Karlsruhe