Characteristics of long-duration inhibitory postsynaptic potentials in rat neocortical neurons in vitro

1. The characteristics of long-duration inhibitory postsynaptic potentials (l-IPSPs) which are evoked in rat frontal neocortical neurons by local electrical stimulation were investigated with intracellular recordings from anin vitro slice preparation. 2. Stimulation with suprathreshold intensities evoked l-IPSPs with typical durations of 600–900 msec at resting membrane potential. Conductance increases of 15–60% were measured at the peak amplitude of l-IPSPs (150–250 msec poststimulus). 3. The duration of the conductance increases during l-IPSPs displayed a significant voltage dependence, decreasing as the membrance potential was depolarized and increasing with hyperpolarization. 4. The reversal potential of l-IPSPs is significantly altered by reductions in the extracellular potassium concentration. Therefore it is concluded that l-IPSPs in rat neocortical neurons are generated by the activation of a potassium conductance. 5. l-IPSPs exhibit stimulation fatigue. Stimulation with a frequency of 1 Hz produces a complete fatigue of the conductance increases during l-IPSPs after approximately 20 consecutive stimuli. Recovery from this fatigue requires minutes. 6. l-IPSPs are not blocked by bicuculline but are blocked by baclofen

Intracranial bleeding due to vitamin K deficiency: advantages of using a pediatric intensive care registry

Item does not contain fulltextAIM: To determine the incidence of late intracranial vitamin K deficiency bleeding (VKDB) in The Netherlands using the Dutch Pediatric Intensive Care Evaluation (PICE) registry. METHODS: The PICE registry was used to identify all infants who were admitted to a Dutch pediatric intensive care unit (PICU) with intracranial bleeding between 1 January 2004 and 31 December 2007. Cases of confirmed late intracranial VKDB were used to calculate the incidence for each year. To estimate the completeness of ascertainment of the PICE registry, data from 2005 were compared with general surveillance data from that year. RESULTS: In the 4-year study period, 16/64 (25%) of the infants admitted with intracranial bleeding had late intracranial VKDB, resulting in an overall incidence of 2.1/100,000 live births (95% confidence interval 1.2-3.5). The single-year incidence varied markedly between 0.5 and 3.3 per 100,000 live births. All five ascertained cases in 2005 were identified using the PICE registry, while general surveillance identified only three. CONCLUSIONS: The PICE registry allows ongoing monitoring of the incidence of late intracranial VKDB and appears to be associated with a higher rate of completeness than general surveillance. We propose the use of pediatric intensive care registries to assess the efficacy of national vitamin K prophylactic regimens

Redetermination of kovdorskite, Mg2PO4(OH)·3H2O

The crystal structure of kovdorskite, ideally Mg2PO4(OH)·3H2O (dimagnesium phosphate hydroxide trihydrate), was reported previously with isotropic displacement paramaters only and without H-atom positions [Ovchinnikov et al. (1980 ▶). Dokl. Akad. Nauk SSSR. 255, 351–354]. In this study, the kovdorskite structure is redetermined based on single-crystal X-ray diffraction data from a sample from the type locality, the Kovdor massif, Kola Peninsula, Russia, with anisotropic displacement parameters for all non-H atoms, with all H-atom located and with higher precision. Moreover, inconsistencies of the previously published structural data with respect to reported and calculated X-ray powder patterns are also discussed. The structure of kovdorskite contains a set of four edge-sharing MgO6 octa­hedra inter­connected by PO4 tetra­hedra and O—H⋯O hydrogen bonds, forming columns and channels parallel to [001]. The hydrogen-bonding system in kovdorskite is formed through the water mol­ecules, with the OH− ions contributing little, if any, to the system, as indicated by the long H⋯A distances (>2.50 Å) to the nearest O atoms. The hydrogen-bond lengths determined from the structure refinement agree well with Raman spectroscopic data

Highly fluorinated naphthalenes and bifurcated C–H⋯F–C hydrogen bonding

The synthesis and crystal structures of 1,2,4,5,6,8-hexafluoronaphthalene and 1,2,4,6,8-pentafluoronaphthalene are reported. Intermolecular interactions are dominated by offset stacking and by C–H⋯F–C hydrogen bonds. For hexafluoronaphthalene, molecules are linked in layers with (4,4) network topology via R12(6) C–H⋯(F–C)2 supramolecular synthons that are rationalised by consideration of the calculated electrostatic potential of the molecule. Such an arrangement is prevented by the additional hydrogen atom in pentafluoronaphthalene and molecules instead form tapes via an R12(8) (C–H⋯F)2 synthon. The geometric characteristics of C–H⋯(F–C)2 bifurcated hydrogen bonds have been analysed for crystal structures in the Cambridge Structural Database (6416 crystal structures; 9534 C–H⋯(F–C)2 bifurcated hydrogen bonds). A geometric analysis of these hydrogen bonds has enabled the extent of asymmetry of these hydrogen bonds to be assessed and indicates a preference for symmetrically bifurcated interactions

Final Report: SIREV - Development of a Functional Model

Die Entwicklung eines Funktionsmodells für ein vorausschauendes Radarsystem einschließlich der Integration der Hardware in einen DLR-Hubschrauber und die Entwicklung geeigneter Algorithmen und Software für die Prozessierung wurde durchgeführt. Mit STN Atlas GmbH hat das DLR das System "Sector Imaging Radar for Enhanced Vision" (SIREV) mit IHE Karlsruhe und AeroSensing entwickelt. / Preis: 36,80

Clinical practice: The bleeding child. Part II: Disorders of secondary hemostasis and fibrinolysis

Bleeding complications in children may be caused by disorders of secondary hemostasis or fibrinolysis. Characteristic features in medical history and physical examination, especially of hemophilia, are palpable deep hematomas, bleeding in joints and muscles, and recurrent bleedings. A detailed medical and family history combined with a thorough physical examination is essential to distinguish abnormal from normal bleeding and to decide whether it is necessary to perform diagnostic laboratory evaluation. Initial laboratory tests include prothrombin time and activated partial thromboplastin time. Knowledge of the classical coagulation cascade with its intrinsic, extrinsic, and common pathways, is useful to identify potential defects in the coagulation in order to decide which additional coagulation tests should be performed

Transcriptional Mechanisms of Proneural Factors and REST in Regulating Neuronal Reprogramming of Astrocytes

© 2015 Elsevier Inc. Direct lineage reprogramming induces dramatic shifts in cellular identity, employing poorly understood mechanisms. Recently, we demonstrated that expression of Neurog2 or Ascl1 in postnatal mouse astrocytes generates glutamatergic or GABAergic neurons. Here, we take advantage of this model to study dynamics of neuronal cell fate acquisition at the transcriptional level. We found that Neurog2 and Ascl1 rapidly elicited distinct neurogenic programs with only a small subset of shared target genes. Within this subset, only NeuroD4 could by itself induce neuronal reprogramming in both mouse and human astrocytes, while co-expression with Insm1 was required for glutamatergic maturation. Cultured astrocytes gradually became refractory to reprogramming, in part by the repressor REST preventing Neurog2 from binding to the NeuroD4 promoter. Notably, in astrocytes refractory to Neurog2 activation, the underlying neurogenic program remained amenable to reprogramming by exogenous NeuroD4. Our findings support a model of temporal hierarchy for cell fate change during neuronal reprogramming

Evaluating energy flows through jellyfish and gulf menhaden (Brevoortia patronus) and the effects of fishing on the northern Gulf of Mexico ecosystem

Fishery management production models tend to stress only the elements directly linked to fish (i.e. fish, fish food, and fish predators). Large coastal jellyfish are major consumers of plankton in heavily fished ecosystems; yet, they are frequently not included as model components. We explore the relationship between gulf menhaden (Brevoortia patronus) and the large scyphozoan jellyfish (Aurelia spp. and Chrysaora sp.), and provide an examination of trophic energy transfer pathways to higher trophic levels in the northern Gulf of Mexico. A trophic network model developed within the ECOPATH framework was transformed to an end-to-end model to map foodweb energy flows. Relative changes in functional group productivity to varying gulf menhaden consumption rates, jellyfish consumption rates, and forage fish (i.e. gulf menhaden, anchovies, and herrings) harvest rates were evaluated within a suite of static, alternative energy-demand scenarios using ECOTRAN techniques. Scenario analyses revealed forage fish harvest enhanced jellyfish productivity, which, in turn, depressed menhaden productivity. Modelled increases in forage fish harvest caused pronounced changes in ecosystem structure, affecting jellyfish, marine birds, piscivorous fish, and apex predators. Menhaden were found to be a more efficient and important energy transfer pathway to higher trophic levels compared with jellyfish. A simulated increase in jellyfish abundance caused the relative production of all model groups to decline. These outcomes suggest that jellyfish blooms and forage fish harvest have demonstrable effects on the structure of the northern Gulf of Mexico ecosystem.Keywords: Gulf of Mexico, forage fish, ECOPATH, foodweb, ECOTRAN, jellyfish, Gulf menhaden, ecosystem-based fishery management, ecosystem modelKeywords: Gulf of Mexico, forage fish, ECOPATH, foodweb, ECOTRAN, jellyfish, Gulf menhaden, ecosystem-based fishery management, ecosystem mode