Regulation of Ang2 release by PTEN/PI3-kinase/Akt in lung microvascular endothelial cells

Angiopoietin-2 (Ang2) is a Tie-2 ligand that destabilizes vascular structures, allowing for neovascularization or vessel regression depending on local vascular endothelial cell growth factor (VEGF) concentrations. Although various stimuli have been shown to affect Ang2 expression, information on the underlying mechanisms involved in Ang2 production in endothelial cells (EC) is just beginning to emerge. In the present study, we have used adenovirus-mediated gene transfer and pharmacological inhibitors to examine the role of the PTEN/PI3-K/Akt pathway on Ang2 release. Inhibition of PI3-kinase with wortmannin led to a stimulation of basal Ang2 release in EC, while overexpression of an active form of Akt reduced Ang2. In addition, adenovirus-mediated gene transfer of the phosphatase PTEN stimulated Ang2 release. Incubation of the cells with Ang1, an agent that activates the PI3-K/Akt pathway in EC, reduced Ang2 release. This effect of Ang1 could be prevented by wortmannin and LY-294002 pretreatment. Similarly, in VEGF-treated EC the increase in Ang2 production observed was greater in the presence of a PI3-K inhibitor. Our observations that PTEN acts as a positive modulator of Ang2 release, while activation of the PI3-K/Akt pathway downregulates Ang2, reveal an additional mechanism through which the PTEN/PI3-K/Akt pathway could affect the angiogenic process.     

Estimation of roe deerCapreolus capreolus and mouflonOvis aries densities, abundance and habitat use in a mountainous Mediterranean area

The abundance, density, and habitat use of roe deerCapreolus capreolus (Linnaeus, 1758) and mouflonOvis aries Linnaeus, 1758 were studied in a confined Mediterranean area in Greece with a dung survey based on the faecal accumulation rate (FAR) technique. Estimated density was modelled with generalized additive models using altitude, habitat type, and slope as potential covariates. Model selection among the set of candidate models was conducted based on their generalized cross-validation score. Roe deer had an estimated mean density of 13.9 ind./km² and the best model included slope and habitat type as covariates. The mean density of mouflon in the study area was 22.1 ind./km² and the best model used altitude and habitat type as covariates. For both species, the highest densities were encountered in abandoned cultivations and glades, followed by conifer forests, while the lowest densities were observed in maquis. However, use of open habitats by mouflon was much greater than it was for roe deer. The strong preference of mouflon (a grazer species) for open habitats that were abundant with grasses probably reflected food availability and contrasted with the more diverse habitat use by roe deer (a selective browser).     

Quantification of Superoxide Radical in the Brain of Rats with Experimentally Induced Obstructive Jaundice

The study aimed to directly measure in vivo superoxide radical (O₂⁻) a direct indicator of oxidative stress, in the brain of rats with experimentally induced obstructive jaundice by employing a new quantitative ultrasensitive fluorescent assay requiring minimum sample. O₂⁻ anion is specific for dihydroethidine (DHE) and upon reaction gives a characteristic product, namely 2-OH-ethidium. Ten male rats underwent laparotomy and were divided into two groups: I, sham operated and II bile duct ligation. Ten days later, following injection with DHE (a O₂⁻ trap), all animals were killed and samples from cerebral cortex, midbrain and cerebellum were removed for analysis. It was shown that compared to group I, in group II the O₂⁻ was increased by 67% in the cerebral cortex and by 37% in the midbrain as a consequence of experimental obstructive jaundice, while its levels were unaffected in the cerebellum. The data in this experimental obstructive jaundice model imply a region-specific increase of O₂⁻ formation rate, being higher in cerebral cortex, less so in the midbrain and not at all in cerebellum.     

Nitric oxide, stomatal closure, and abiotic stress

Various data indicate that nitric oxide (NO) is an endogenoussignal in plants that mediates responses to several stimuli.Experimental evidence in support of such signalling roles forNO has been obtained via the application of NO, usually in theform of NO donors, via the measurement of endogenous NO, andthrough the manipulation of endogenous NO content by chemicaland genetic means. Stomatal closure, initiated by abscisic acid(ABA), is effected through a complex symphony of intracellularsignalling in which NO appears to be one component. ExogenousNO induces stomatal closure, ABA triggers NO generation, removalof NO by scavengers inhibits stomatal closure in response toABA, and ABA-induced stomatal closure is reduced in mutantsthat are impaired in NO generation. The data indicate that ABA-inducedguard cell NO generation requires both nitric oxide synthase-likeactivity and, in Arabidopsis, the NIA1 isoform of nitrate reductase(NR). NO stimulates mitogen-activated protein kinase (MAPK)activity and cGMP production. Both these NO-stimulated eventsare required for ABA-induced stomatal closure. ABA also stimulatesthe generation of H₂O₂ in guard cells, and pharmacological andgenetic data demonstrate that NO accumulation in these cellsis dependent on such production. Recent data have extended thismodel to maize mesophyll cells where the induction of antioxidantdefences by water stress and ABA required the generation ofH₂O₂ and NO and the activation of a MAPK. Published data suggestthat drought and salinity induce NO generation which activatescellular processes that afford some protection against the oxidativestress associated with these conditions. Exogenous NO can alsoprotect cells against oxidative stress. Thus, the data suggestan emerging model of stress responses in which ABA has severalameliorative functions. These include the rapid induction ofstomatal closure to reduce transpirational water loss and theactivation of antioxidant defences to combat oxidative stress.These are two processes that both involve NO as a key signallingintermediate. Key words: Abscisic acid, antioxidants, guard cells, hydrogen peroxide, nitric oxide, oxidative stress, stomata, water stress Received 19 June 2007; Revised 21 September 2007 Accepted 5 November 2007     

Brasiliporella, a new mid-Cretaceous dasycladacean genus: the earliest record of the Tribe Batophoreae

New material collected in Albian and Cenomanian strata from Brazil helps us to better understand the structure of a poorly known dasycladacean alga, Holosporella nkossaensis P. Masse, in Bull Centr Rech Explor-Prod elf aquitaine, 19: 301–317, 1995: each of its fertile laterals, which are regularly arranged in verticils along the cylindrical algal thallus, consists of a distally inflated primary bearing two vesicular ampullae in terminal position. These traits are not known in representatives of the genus Holosporella Pia, 1930 nor in any genera described to date. On this basis, we introduce the new genus Brasiliporella with Brasiliporella nkossaensis emend. nov. comb. as its type-species. We also discuss the systematic affinity of the new taxon: it is ascribed to the Tribe Batophoreae, and in a broader manner the current paleontological ‘interpretation of the concept’ (in French: ‘acception’) of the Order Dasycladales, with the creation of two new families and accordingly with the emendation of two other families.     

Curriculum for education and training of Medical Physicists in Nuclear Medicine: Recommendations from the EANM Physics Committee,the EANM Dosimetry Committee and EFOMP

PurposeTo provide a guideline curriculum covering theoretical and practical aspects of education and training for Medical Physicists in Nuclear Medicine within Europe.Material and methodsNational training programmes of Medical Physics, Radiation Physics and Nuclear Medicine physics from a range of European countries and from North America were reviewed and elements of best practice identified. An independent panel of experts was used to achieve consensus regarding the content of the curriculum.ResultsGuidelines have been developed for the specialist theoretical knowledge and practical experience required to practice as a Medical Physicist in Nuclear Medicine in Europe. It is assumed that the precondition for the beginning of the training is a good initial degree in Medical Physics at master level (or equivalent). The Learning Outcomes are categorised using the Knowledge, Skill and Competence approach along the lines recommended by the European Qualifications Framework. The minimum level expected in each topic in the theoretical knowledge and practical experience sections is intended to bring trainees up to the requirements expected of a Medical Physicist entering the field of Nuclear Medicine.ConclusionsThis new joint EANM/EFOMP European guideline curriculum is a further step to harmonise specialist training of Medical Physicists in Nuclear Medicine within Europe. It provides a common framework for national Medical Physics societies to develop or benchmark their own curricula. The responsibility for the implementation and accreditation of these standards and guidelines resides within national training and regulatory bodies.     

Anthropogenic disturbance of coastal habitats promotes the spread of the introduced scleractinian coral Oculina patagonica in the Mediterranean Sea

The extensive human-mediated modifications of shallow coastal habitats drastically alter selection regimes and may assist alien invasions. The preferential presence of a non-indigenous scleractinian coral (Oculina patagonica) on anthropogenic hard substrata was investigated in a highly disturbed coastal area, along the eastern Saronikos Gulf (Aegean Sea, Eastern Mediterranean). Although the species occurred on both natural and anthropogenic substrata at similar frequencies, its abundance was substantially higher on the latter. The species was present all along the shallow (0.5–5 m) infralittoral zone of the studied coastline, and its percent cover even exceeded 50 % at a site of anthropogenic hard substratum. The occupancy of the species declined with distance from a highly disturbed industrialized/urbanized area (Athens metropolitan coastal front and the port of Piraeus). Space availability as a result of habitat modification appears to have been an important factor enhancing the coral’s abundance in this area. The ongoing degradation of the coastal zone, as a combined effect of coastal pollution, proliferation of artificial substrata and overgrazing seems to be paving the way to this new invasion in the Aegean Sea.