bluuebunny/crossref_metadata_2025 huggingface dataset:
Temporal redistribution of inhibition over neuronal subcellular domains underlies state-dependent rhythmic change of excitability in the hippocampus
Authors: Somogyi Peter , Katona Linda , Klausberger Thomas , Lasztóczi Bálint , Viney Tim J.
Published: December 2013

The behaviour-contingent rhythmic synchronization of neuronal activity is reported by local field potential oscillations in the theta, gamma and sharp wave-related ripple (SWR) frequency ranges. In the hippocampus, pyramidal cell assemblies representing temporal sequences are coordinated by GABAergic interneurons selectively innervating specific postsynaptic domains, and discharging phase locked to network oscillations. We compare the cellular network dynamics in the CA1 and CA3 areas recorded with or without anaesthesia. All parts of pyramidal cells, except the axon initial segment, receive GABA from multiple interneuron types, each with distinct firing dynamics. The axon initial segment is exclusively innervated by axo-axonic cells, preferentially firing after the peak of the pyramidal layer theta cycle, when pyramidal cells are least active. Axo-axonic cells are inhibited during SWRs, when many pyramidal cells fire synchronously. This dual inverse correlation demonstrates the key inhibitory role of axo-axonic cells. Parvalbumin-expressing basket cells fire phase locked to field gamma activity in both CA1 and CA3, and also strongly increase firing during SWRs, together with dendrite-innervating bistratified cells, phasing pyramidal cell discharge. Subcellular domain-specific GABAergic innervation probably developed for the coordination of multiple glutamatergic inputs on different parts of pyramidal cells through the temporally distinct activity of GABAergic interneurons, which differentially change their firing during different network states.
How to build a grid cell
Authors: Schmidt-Hieber Christoph , Häusser Michael
Published: December 2013

Neurons in the medial entorhinal cortex fire action potentials at regular spatial intervals, creating a striking grid-like pattern of spike rates spanning the whole environment of a navigating animal. This remarkable spatial code may represent a neural map for path integration. Recent advances using patch-clamp recordings from entorhinal cortex neurons
in vitro
and
in vivo
have revealed how the microcircuitry in the medial entorhinal cortex may contribute to grid cell firing patterns, and how grid cells may transform synaptic inputs into spike output during firing field crossings. These new findings provide key insights into the ingredients necessary to build a grid cell.
An isomorphic mapping hypothesis of the grid representation
Authors: Brecht Michael , Ray Saikat , Burgalossi Andrea , Tang Qiusong , Schmidt Helene , Naumann Robert
Published: December 2013

We introduce a grid cell microcircuit hypothesis. We propose the ‘grid in the world’ (evident in grid cell discharges) is generated by a ‘grid in the cortex’. This cortical grid is formed by patches of calbindin-positive pyramidal neurons in layer 2 of medial entorhinal cortex (MEC). Our isomorphic mapping hypothesis assumes three types of isomorphism: (i) metric correspondence of neural space (the two-dimensional cortical sheet) and the external two-dimensional space within patches; (ii) isomorphism between cellular connectivity matrix and firing field; (iii) isomorphism between single cell and population activity. Each patch is a grid cell lattice arranged in a two-dimensional map of space with a neural : external scale of approximately 1 : 2000 in the dorsal part of rat MEC. The lattice behaves like an excitable medium with neighbouring grid cells exciting each other. Spatial scale is implemented as an intrinsic scaling factor for neural propagation speed. This factor varies along the dorsoventral cortical axis. A connectivity scheme of the grid system is described. Head direction input specifies the direction of activity propagation. We extend the theory to neurons between grid patches and predict a rare discharge pattern (inverted grid cells) and the relative location and proportion of grid cells and spatial band cells.
Selection of preconfigured cell assemblies for representation of novel spatial experiences
Authors: Dragoi George , Tonegawa Susumu
Published: December 2013

Internal representations about the external world can be driven by the external stimuli or can be internally generated in their absence. It has been a matter of debate whether novel stimuli from the external world are instructive over the brain network to createde novorepresentations or, alternatively, are selecting from existing pre-representations hosted in preconfigured brain networks. The hippocampus is a brain area necessary for normal internally generated spatial–temporal representations and its dysfunctions have resulted in anterograde amnesia, impaired imagining of new experiences, and hallucinations. The compressed temporal sequence of place cell activity in the rodent hippocampus serves as an animal model of internal representation of the external space. Based on our recent results on the phenomenon of novel place cell sequence preplay, we submit that the place cell sequence of a novel spatial experience is determined, in part, by a selection of a set of cellular firing sequences from a repertoire of existing temporal firing sequences in the hippocampal network. Conceptually, this indicates that novel stimuli from the external world select from their pre-representations rather than createde novoour internal representations of the world.
Neuronal rebound spiking, resonance frequency and theta cycle skipping may contribute to grid cell firing in medial entorhinal cortex
Authors: Hasselmo Michael E.
Published: December 2013

Data show a relationship of cellular resonance and network oscillations in the entorhinal cortex to the spatial periodicity of grid cells. This paper presents a model that simulates the resonance and rebound spiking properties of entorhinal neurons to generate spatial periodicity dependent upon phasic input from medial septum. The model shows that a difference in spatial periodicity can result from a difference in neuronal resonance frequency that replicates data from several experiments. The model also demonstrates a functional role for the phenomenon of theta cycle skipping in the medial entorhinal cortex.
Coordinated learning of grid cell and place cell spatial and temporal properties: multiple scales, attention and oscillations
Authors: Grossberg Stephen , Pilly Praveen K.
Published: December 2013

A neural model proposes how entorhinal grid cells and hippocampal place cells may develop as spatial categories in a hierarchy of self-organizing maps (SOMs). The model responds to realistic rat navigational trajectories by learning both grid cells with hexagonal grid firing fields of multiple spatial scales, and place cells with one or more firing fields, that match neurophysiological data about their development in juvenile rats. Both grid and place cells can develop by detecting, learning and remembering the most frequent and energetic co-occurrences of their inputs. The model's parsimonious properties include: similar ring attractor mechanisms process linear and angular path integration inputs that drive map learning; the same SOM mechanisms can learn grid cell and place cell receptive fields; and the learning of the dorsoventral organization of multiple spatial scale modules through medial entorhinal cortex to hippocampus (HC) may use mechanisms homologous to those for temporal learning through lateral entorhinal cortex to HC (‘neural relativity’). The model clarifies how top-down HC-to-entorhinal attentional mechanisms may stabilize map learning, simulates how hippocampal inactivation may disrupt grid cells, and explains data about theta, beta and gamma oscillations. The article also compares the three main types of grid cell models in the light of recent data.
Sharp wave/ripple network oscillations and learning-associated hippocampal maps
Authors: Csicsvari Jozsef , Dupret David
Published: December 2013

Sharp wave/ripple (SWR, 150–250 Hz) hippocampal events have long been postulated to be involved in memory consolidation. However, more recent work has investigated SWRs that occur during active waking behaviour: findings that suggest that SWRs may also play a role in cell assembly strengthening or spatial working memory. Do such theories of SWR function apply to animal learning? This review discusses how general theories linking SWRs to memory-related function may explain circuit mechanisms related to rodent spatial learning and to the associated stabilization of new cognitive maps.
How environment geometry affects grid cell symmetry and what we can learn from it
Authors: Krupic Julija , Bauza Marius , Burton Stephen , Lever Colin , O'Keefe John
Published: December 2013

The mammalian hippocampal formation provides neuronal representations of environmental location but the underlying mechanisms are unclear. The majority of cells in medial entorhinal cortex and parasubiculum show spatially periodic firing patterns. Grid cells exhibit hexagonal symmetry and form an important subset of this more general class. Occasional changes between hexagonal and non-hexagonal firing patterns imply a common underlying mechanism. Importantly, the symmetrical properties are strongly affected by the geometry of the environment. Here, we introduce a field–boundary interaction model where we demonstrate that the grid cell pattern can be formed from competing place-like and boundary inputs. We show that the modelling results can accurately capture our current experimental observations.
A theoretical account of cue averaging in the rodent head direction system
Authors: Page Hector J. I. , Walters Daniel M. , Knight Rebecca , Piette Caitlin E. , Jeffery Kathryn J. , Stringer Simon M.
Published: December 2013

Head direction (HD) cell responses are thought to be derived from a combination of internal (or idiothetic) and external (or allothetic) sources of information. Recent work from the Jeffery laboratory shows that the relative influence of visual versus vestibular inputs upon the HD cell response depends on the disparity between these sources. In this paper, we present simulation results from a model designed to explain these observations. The model accurately replicates the Knightet al.data. We suggest that cue conflict resolution is critically dependent on plastic remapping of visual information onto the HD cell layer. This remap results in a shift in preferred directions of a subset of HD cells, which is then inherited by the rest of the cells during path integration. Thus, we demonstrate how, over a period of several minutes, a visual landmark may gain cue control. Furthermore, simulation results show that weaker visual landmarks fail to gain cue control as readily. We therefore suggest a second longer term plasticity in visual projections onto HD cell areas, through which landmarks with an inconsistent relationship to idiothetic information are made less salient, significantly hindering their ability to gain cue control. Our results provide a mechanism for reliability-weighted cue averaging that may pertain to other neural systems in addition to the HD system.
Independence of landmark and self-motion-guided navigation: a different role for grid cells
Authors: Poucet Bruno , Sargolini Francesca , Song Eun Y. , Hangya Balázs , Fox Steven , Muller Robert U.
Published: December 2013

Recent interest in the neural bases of spatial navigation stems from the discovery of neuronal populations with strong, specific spatial signals. The regular firing field arrays of medial entorhinal grid cells suggest that they may provide place cells with distance information extracted from the animal's self-motion, a notion we critically review by citing new contrary evidence. Next, we question the idea that grid cells provide a rigid distance metric. We also discuss evidence that normal navigation is possible using only landmarks, without self-motion signals. We then propose a model that supposes that information flow in the navigational system changes between light and dark conditions. We assume that the true map-like representation is hippocampal and argue that grid cells have a crucial navigational role only in the dark. In this view, their activity in the light is predominantly shaped by landmarks rather than self-motion information, and so follows place cell activity; in the dark, their activity is determined by self-motion cues and controls place cell activity. A corollary is that place cell activity in the light depends on non-grid cells in ventral medial entorhinal cortex. We conclude that analysing navigational system changes between landmark and no-landmark conditions will reveal key functional properties.
Elastic macro strain and stress determination by powder diffraction: spherical harmonics analysis starting from the Voigt model
Authors: Popa Nicolae C. , Balzar Davor , Vogel Sven C.
Published: December 2013

A new approach for the determination of the elastic macro strain and stress in textured polycrystals by diffraction is presented. It consists of expanding the strain tensor weighted by texture in a series of generalized spherical harmonics where the ground state is defined by the strain/stress state in an isotropic sample in the Voigt model. In contrast to similar expansions already reported by other authors, this new approach provides expressions valid for any sample and crystal symmetries and can easily be implemented in whole powder pattern fitting, including Rietveld refinement. An earlier article [Popa & Balzar (2001).J. Appl. Cryst.34, 187–195] reported a similar model, but with a spherical harmonics expansion around the hydrostatic strain/stress state of the isotropic polycrystal. The availability of several different models is beneficial in order to allow one to select the representation in which the ground state is the closest to the actual stress state in the sample.
Accuracy in quantitative phase analysis of mixtures with large amorphous contents. The case of zircon-rich sanitary-ware glazes
Authors: Bernasconi Andrea , Dapiaggi Monica , Gualtieri Alessandro F.
Published: December 2013

The accuracy of quantitative phase analysis (QPA) of samples with dominant amorphous content, reproducing zircon-rich sanitary-ware glazes, has been investigated. X-ray powder diffraction (XRPD) methods were applied using both conventional Cu Kα radiation and high-resolution synchrotron data. In this work, a combination of the reference intensity ratio (RIR) and Rietveld methods was applied to an artificial mixture (90 wt% glass, 10 wt% zircon), taking into account some of the most common effects that may affect the accuracy in amorphous quantification, such as the degree of crystallinity of the phases, microabsorption and sample preparation. Certified NIST SRM 676a (α-Al2O3) [Cline, Von Dreele, Winburn, Stephens & Filliben (2011).Acta Cryst.A67, 357–367] was used to quantify the amorphous content in zircon and in the different internal standards commonly used when a certified standard is not available or not applicable: the results show that all of the phases invariably contain amorphous material in the range 2.0–15.0 wt%. If the amorphous content of the standard is taken into account, the accuracy of the QPA of the artificial mixture is improved. It was observed that the Brindley correction for microabsorption does not significantly improve the results. Care must be applied if grinding time is increased, since this may increase the amorphous content in the sample. Finally, the sensitivity of the RIR–Rietveld method to the addition of a small amount of zircon (∼1 wt%) has been considered, showing that accurate results can be achieved if great care is taken in the sample preparation and refinement strategy.
Global small-angle X-ray scattering data analysis for multilamellar vesicles: the evolution of the scattering density profile model
Authors: Heftberger Peter , Kollmitzer Benjamin , Heberle Frederick A. , Pan Jianjun , Rappolt Michael , Amenitsch Heinz , Kučerka Norbert , Katsaras John , Pabst Georg
Published: December 2013

The highly successful scattering density profile (SDP) model, used to jointly analyze small-angle X-ray and neutron scattering data from unilamellar vesicles, has been adapted for use with data from fully hydrated, liquid crystalline multilamellar vesicles (MLVs). Using a genetic algorithm, this new method is capable of providing high-resolution structural information, as well as determining bilayer elastic bending fluctuations from standalone X-ray data. Structural parameters such as bilayer thickness and area per lipid were determined for a series of saturated and unsaturated lipids, as well as binary mixtures with cholesterol. The results are in good agreement with previously reported SDP data, which used both neutron and X-ray data. The inclusion of deuterated and non-deuterated MLV neutron data in the analysis improved the lipid backbone information but did not improve, within experimental error, the structural data regarding bilayer thickness and area per lipid.
The coordination chemistry of two symmetric fluorene-based organic ligands with cuprous chloride. Corrigendum
Authors: Liu Yan-Fei , Zhao Chao-Wei , Ma Jian-Ping , Liu Qi-Kui , Dong Yu-Bin
Published: December 2013

Errors in the elemental analysis results in the paper by Liuet al.[Acta Cryst.(2013), C69, 1488–1493] are corrected.
In vitro biofilm formation by Streptococcus pneumoniae as a predictor of post‐vaccination emerging serotypes colonizing the human nasopharynx
Authors: Domenech Mirian , Araújo‐Bazán Lidia , García Ernesto , Moscoso Miriam
Published: December 2013

The increasing use of the 7‐valent pneumococcal conjugate vaccine has been accompanied by the rise of non‐vaccine serotypes colonizing the human nasopharynx. The vast majority of infections are caused by microorganisms that grow in biofilms. It has recently been shown that the formation of Streptococcus pneumoniae biofilms in vivo and in vitro is hindered by the presence of capsular polysaccharide. The biofilm‐forming capacity of pneumococcal clinical isolates with different types of capsular polysaccharide and various isogenic transformants was examined. Strains of serotypes 19A and 19F, but not 19B and 19C, formed ≥ 80% of the quantity of biofilm associated with a non‐encapsulated control strain. Strains of serogroup 6 also showed significant biofilm‐forming capacity. The capsules of serotypes 19A and 19F, and serogroup 6 contain the disaccharides α‐D‐Glcp‐(1→2)‐α‐L‐Rhap‐(1→ and α‐D‐Glcp‐(1→3)‐α‐L‐Rhap‐(1→. Serotype 18A and serotypes 18B/18C have very similar capsular disaccharides: α‐D‐GlcpNAc‐(1→3)‐β‐L‐Rhap‐(1→ and α‐D‐Glcp‐(1→3)‐β‐L‐Rhap‐(1→ respectively. However, the strains of serogroup 18 showed impaired biofilm formation. These results indicate that the chemical composition/structure of the capsular polysaccharide is crucial to the biofilm‐forming capacity of pneumococcal serotypes. Testing of the in vitro biofilm‐forming ability of isogenic transformants expressing different capsular polysaccharides may help predict the emergence of colonizing, non‐vaccine serotypes.
The Prc and RseP proteases control bacterial cell‐surface signalling activity
Authors: Bastiaansen Karlijn C. , Ibañez Aurelia , Ramos Juan L. , Bitter Wilbert , Llamas María A.
Published: December 2013

Extracytoplasmic function (ECF) sigma factors play a key role in the regulation of vital functions in the bacterial response to the environment. In Gram‐negative bacteria, activity of these sigma factors is often controlled by cell‐surface signalling (CSS), a regulatory system that also involves an outer membrane receptor and a transmembrane anti‐sigma factor. To get more insight into the molecular mechanism behind CSS regulation, we have focused on the unique Iut system of Pseudomonas putida. This system contains a hybrid protein containing both a cytoplasmic ECF sigma domain and a periplasmic anti‐sigma domain, apparently leading to a permanent interaction between the sigma and anti‐sigma factor. We show that the Iut ECF sigma factor regulates the response to aerobactin under iron deficiency conditions and is activated by a proteolytic pathway that involves the sequential action of two proteases: Prc, which removes the periplasmic anti‐sigma domain, and RseP, which subsequently removes the transmembrane domain and thereby generates the ECF active transcriptional form. We furthermore demonstrate the role of these proteases in the regulation of classical CSS systems in which the sigma and anti‐sigma factors are two different proteins.
Optimization and evaluation of microencapsulated artificial diet for mass rearing the predatory ladybird Propylea japonica (Coleoptera: Coccinellidae)
Authors: Tan Xiao‐Ling , Zhao Jing , Wang Su , Zhang Fan
Published: December 2013

Artificial diet optimization is a key aspect in mass rearing of natural enemies since it influences the quality and feeding effectiveness, and thus the success of the biological control program. Here, we introduced the microencapsulation method to package liquid artificial diet for feeding of the ladybird Propylea japonica. An orthogonal test of the quality of microencapsulated artificial diets (ADMs) was performed on key variables in production; Ca‐alginate concentration, chitosan concentration and weight ratio of wall material to inner diet. We compared the development and reproduction of P. japonica fed on the ADMs under different cold‐stored periods with those fed on fresh aphids and liquid artificial diets, in addition to a comparison of respiration, locomotion and predation. Our results indicated that chitosan concentration and ratio of shell to core significantly influence the quality of ADMs. The optimal recipe is 1.0% Ca‐alginate, 1.6% chitosan and shell : core = 1 : 2. Insects reared on fresh optimized ADMs were similar to those fed on fresh prey in all developmental and reproductive characteristics except for survival ratio and female fertility. ADMs appeared more beneficial than using a liquid artificial diet, although this may decrease with the prolonging of the cold‐storage period. P. japonica fed either on fresh ADMs or fresh prey showed improved respiration and predation abilities compared to where liquid artificial diet was used. Our study indicates advantages of microencapsulation in the production of artificial diet for predatory ladybird rearing. A microencapsulated diet can directly increase the efficiency and stability of mass rearing.
The negative effects of temperature increase on bacterial respiration are independent of changes in community composition
Authors: Pires Aliny P. F. , Guariento Rafael D. , Laque Thais , Esteves Francisco A. , Farjalla Vinicius F.
Published: December 2013

Temporal changes in environmental conditions and in bacterial community composition (BCC) regulate bacterial processes and ecosystem services. An increase in temperature accelerates bacterial processes in polar or temperate regions, but this relationship has not been documented for the tropics. Here, we tested the interactive effects of changing the BCC and increasing the water temperature on tropical bacterial respiration (BR). The BCC was manipulated through successional changes of the bacterial community in a filtered water sample from a tropical coastal lagoon. Four succession incubation periods (120, 240, 288 and 336 h) and four different water temperatures (23, 28, 33 and 38oC) were tested in a full‐factorial design microcosm experiment. Both the BCC and the temperature had significant individual, but not interactive, effects on BR. Temperature increasing consistently decreased BR, while there was no clear pattern of successional effects on BR observed. No BCC tested was able to diminish the negative effects of temperature increases on BR. Our results suggest that the effects of an increasing temperature can negatively affect BR, even in tropical ecosystems with different BCC.
A comparison of Maxlike and Maxent for modelling species distributions
Authors: Merow Cory , Silander John A.
Published: December 2013

Understanding species spatial occurrence patterns and their environmental dependence is one of the fundamental goals in ecology and evolution. Often, occurrence models are built with presence‐only data because absence data are unavailable. We compare the strengths and limitations of the recently developed presence‐only modelling method, Maxlike, with the more widely used Maxent.

In spite of disparities highlighted by the developers of Maxlike and Maxent, we show approximate formal relationships between the parameters of Maxlike and Maxent for two scenarios to illustrate their similarity. Using case studies based on real and simulated data, we show how these similarities manifest in practice.

We find more similarities than differences between Maxlike and Maxent, including coefficient values, predicted spatial distributions, similarity to presence–absence models, predictive performance and ranking the predicted suitability of cells. Maxlike reliably predicted absolute occurrence probabilities for very large data sets on landscapes where occurrence probability approximately spanned [0,1]. For smaller data sets, the uncertainty in predicted occurrence probability by Maxlike was very large, due to the inherent limitations of presence‐only data. In contrast, Maxent is constrained to predicting relative occurrence probabilities or relative occurrence rates unless it is provided with additional information from presence–absence data. Both models can reliably predict relative differences in occurrence probability.

The choice of which model to use depends partly on sampling assumptions, which we discuss in detail. Due to limitations of presence‐only data, ecologists should typically focus on interpretations relying on relative differences in occurrence probability or relative occurrence rates. We discuss how to remedy a number of concerns about the use of Maxent and how to avoid some potential pitfalls with Maxlike – particularly related to high variance predictions. We conclude that both methods are similarly valuable for understanding and predicting species’ distributions in terms of relative differences in occurrence probability when the models are specified carefully.
Evaluating rehabilitation goals of visually impaired children in multidisciplinary care according to ICF‐CY guidelines
Authors: Rainey Linda , van Nispen Ruth , van Rens Ger
Published: December 2013

Purpose

To gain qualitative insight into the rehabilitation goals of visually impaired children and how these goals relate to the structure of the International Classification of Functioning, Disability and Health (ICF) and patient characteristics.

Methods

A patient record study was conducted, analysing rehabilitation goals and characteristics of children with a suspected visual impairment in the Netherlands (<18 years) who applied for multidisciplinary services in 2012 (N = 289). Chi‐square analyses for trend in rehabilitation content across age bands and additional analyses were performed.

Results

The three most common diagnoses were nystagmus (21.2%), cerebral visual impairment (16.2%) and albinism (6.1%). Rehabilitation goals for children aged <7 years were mostly aimed at ‘physical (visual) functioning’ (36.7%) and ‘environmental factors’ (36.7%). For children ≥7 years, significantly more goals were identified on activity and participation (A&P) domains (52.2%). Three A and P domains presented a significant linear trend on the number of rehabilitation goals across age bands: (1) ‘Learning and applying knowledge’ (13.042, p < 0.001), (4) ‘Mobility’ (31.340, p < 0.001) and (8) ‘Major life areas’ (5.925, p = 0.015). Regression analysis showed that both age and visual acuity significantly contributed to the number of A and P goals.

Conclusion

Although analyses were based on a selection of patient records, the number and nature of rehabilitation goals differ significantly with age. Many A and P goals seem underrepresented at the intake procedure, for example: communication, peer interaction and participating in leisure activities. A systematic, standardized procedure is required to catalogue all existing goals and to be able to evaluate progress and potential new or other important goals.
Peripapillary ring: histology and correlations
Authors: Jonas Jost B. , Holbach Leonard , Panda‐Jonas Songhomitra
Published: December 2013

Purpose

To assess the histologic correlate of the peripapillary ring (PPR) as the optic disc boundary, to measure it histomorphometrically and to assess its associations with glaucoma and axial length.

Methods

Using a light microscope, we measured the width of the PPR and optic nerve pia mater. We additionally had measured the axial length, length of parapapillary beta and gamma zones, and thickness of the sclera and choroid.

Results

The study included 83 human globes with a mean axial length of 26.1 ± 3.3 mm (range: 20.0–35.0 mm). In the non‐highly myopic (axial length <26.5 mm) non‐glaucomatous eyes, mean PPR width was 55 ± 14 μm (range: 26–88 μm) and mean thickness of the optic nerve pia mater was 52 ± 22 μm (range: 20–84 μm). PPR width and pia mater thickness were significantly associated with each other (p = 0.001; correlation coefficient r = 0.37). PPR width increased significantly with longer axial length (p = 0.001; r = 0.35) and with the length of the peripapillary scleral flange (p = 0.02; r = 0.34). Pia mater thickness increased significantly with longer axial length (p = 0.03; r = 0.24) and with presence of glaucoma (p = 0.03). In eyes without parapapillary gamma zone, PPR was covered or was at least touched by the end of Bruch's membrane and separated the peripapillary choroid from the prelaminar optic nerve head tissue. In eyes with parapapillary gamma zone, PPR was the continuation of the optic nerve pia mater and reached the undersurface of the peripapillary retinal nerve fibre layer. In these eyes, Bruch's membrane started in a distance of up to 5 mm from PPR, and the thin space of peripapillary choroid ended by an attachment of Bruch's membrane to the thinned sclera.

Conclusions

Peripapillary ring width (mean: 55 ± 14 μm) increases slightly with longer axial length and is independent of glaucoma. It is strongly correlated with the pia mater thickness and is the continuation of the pia mater to the ocular surface.
Nogo‐B expression, in arterial intima, is impeded in the early stages of atherosclerosis in humans
Authors: Drożdż Katarzyna , Grzegorek Irmina , Chmielewska Magdalena , Gomułkiewicz Agnieszka , Jabłońska Karolina , Piotrowska Aleksandra , Karczewski Maciej , Janczak Dariusz , Patrzałek Dariusz , Dzięgiel Piotr , Szuba Andrzej
Published: December 2013

Nogo‐B (Reticulon 4B) is considered to be a novel vascular marker, which may have a protective role in injury‐induced neointima formation and atherosclerosis. Nogo A/B is found to be crucial for monocyte/macrophage recruitment in acute inflammation and it is expressed in CD68 + macrophages. We hypothesize that macrophage infiltration in atherosclerosis is not dependent on Nogo‐B expression in arterial wall. We have assessed Nogo‐B expression and macrophage accumulation in the iliac arteries of healthy organ donors and organ donors with cardiovascular risk factors. Paraffin sections of 66 iliac arteries, from 44 deceased organ donors (17 women and 27 men), were studied. The healthy and cardiovascular risk (CVR) subgroups were created. With regard to staging of the atherosclerotic process, the thickness of arterial intima was measured in digitalized images of H+E stained tissue sections. Immunohistochemical reactions (Nogo‐B and CD68) were carried out in all arteries (66 samples). Western blotting (WB‐19 samples) and real‐time PCR (27 samples) were performed on selected arteries. Significantly higher Nogo‐B expression was demonstrated in the intima of the healthy subjects' subgroup, using immunohistochemistry. WB and real‐time PCR revealed a trend toward lower Nogo‐B expression in the adventitia of the CVR subgroup. Furthermore, the thickness of the intima was found to negatively correlate with the expression of Nogo‐B in the intima and media (r = −0.32; p < 0.05; r = −0.32; p < 0.05). Macrophage infiltrates were more prominent in intima of CVR subjects (0.65 vs 3.52 a.u.; p < 0.01). Macrophage density in intima increased with atherosclerosis progression (r = 0.37; p < 0.01). CD68 macrophages density in adventitia was lower in CVR arteries than in healthy arteries. The expression of Nogo‐B, in arterial intima, is impeded in the early stages of atherosclerosis. Accumulation of arterial intimal CD68 macrophages has been shown to progress; however, the overall macrophage density in the adventitia is reduced in arteries shown to have intimal thickening. Macrophage infiltration is not accompanied by Nogo‐B expression in atherosclerotic arteries.
Triphasic differentiations of Merkel cell carcinoma in primary and metastatic lesions
Authors: Koba Shinichi , Misago Noriyuki , Nagase Kotaro , Tsuruta Noriko , Inoue Takuya , Ikeda Satoshi , Aoki Shigehisa , Narisawa Yutaka
Published: December 2013

We present a rare case of Merkel cell carcinoma (MCC) with heterologous differentiation. The patient was an 86‐year‐old female patient with MCC who presented with a forearm skin tumor and left axillary lymph node swelling. Histopathologically, the malignant components of the primary and metastatic lesions showed the intermingled features of triphasic phenotype differentiation, which had distinct cell populations; MCC, sweat gland carcinoma (SGC) and malignant poorly differentiated spindle cells with myogenic differentiation were immunohistochemically showed. Moreover, an electron microscopic observation of the tumor cells revealed intracytoplasmic canaliculi and junctional structures that indicated ductal differentiation. To our knowledge, this is the first case of MCC admixed with SGC and sarcomatous components in both the primary and metastatic lesions. An immunohistochemical study, using several stem cell markers, indicated that the MCC arose from pluripotent epidermal stem cells.
A New Approach to the Group Ranking Problem: Finding Consensus Ordered Segments from Users’ Preference Data
Authors: Chen Yen‐Liang , Cheng Li‐Chen , Hsu Weu‐Yu
Published: December 2013

The group ranking problem involves constructing coherent aggregated results from users’ preference data. The goal of most group ranking problems is to generate an ordered list of all items that represents the user consensus. There are, however, two weaknesses to this approach. First, a complete list of ranked items is always output even when there is no consensus or only a slight consensus. Second, due to similarity of performance, in many practical situations, it is very difficult to differentiate whether one item is really better than another within a set. These weaknesses have motivated us to apply the clustering concept to the group ranking problem, to output an ordered list of segments containing a set of similarly preferred items, called consensus ordered segments. The advantages of our approach are that (i) the list of segments is based on the users’ consensuses, (ii) the items with similar preferences are grouped together in the same segment, and (iii) the relationships between items can be easily seen. An algorithm is developed to construct the consensus of the ordered segments from the users’ total ranking data. Finally, the experimental results indicate that the proposed method is computationally efficient, and can effectively identify consensus ordered segments.
Decision Making Using Rating Systems: When Scale Meets Binary
Authors: Bargagliotti Anna E. , Li Lingfang (Ivy)
Published: December 2013

This article investigates how different decisions can be reached when decision makers consult a binary rating system and a scale rating system. Since typically decision makers use rating information to make binary decisions, it is particularly important to compare the scale system to the binary system. We show that the only N‐point scale system that reports a rater's opinion consistently with the binary system is one where N is odd and is not divisible by 4. At the aggregate level, however, we illustrate that inconsistencies persist regardless of the choice of N. In addition, we provide simple tools that can determine whether the systems lead decision makers to the same decision outcomes.
A randomized controlled trial comparing the GLP‐1 receptor agonist liraglutide to a sulphonylurea as add on to metformin in patients with established type 2 diabetes during Ramadan: the Treat 4 Ramadan Trial
Authors: Brady E. M. , Davies M. J. , Gray L. J. , Saeed M. A. , Smith D. , Hanif W. , Khunti K.
Published: December 2013

Aims

To compare a sulphonylurea with the glucagon like peptide‐1 (GLP‐1) receptor agonist liraglutide in combination with metformin in patients on mono/dual oral therapy with established type 2 diabetes fasting during Ramadan.

Methods

Ninety‐nine adults intending to fast during Ramadan [50% male, mean age 52 years, body mass index (BMI) 32 kg/m2] were randomized from two UK sites. Baseline data were collected ≥14 days prior to Ramadan and at 3 and 12 weeks after Ramadan.

Results

At 12 weeks, more patients in the liraglutide compared with the sulphonylurea group achieved a composite endpoint of haemoglobin A1c (HbA1c) < 7%, no weight gain and no severe hypoglycaemia but this did not reach statistical significance [odds ratio (OR) 4.08, 95% confidence interval (CI) 0.97, 17.22, p = 0.06]. From a baseline of 7.7% there was no change in HbA1c at 12 weeks in the sulphonylurea (+0.02%) compared with a 0.3% reduction in the liraglutide group (adjusted coefficient −0.41, 95% CI −0.83, 0.01, p = 0.05). Significant reductions were also observed in weight and diastolic blood pressure (BP) in the liraglutide compared with the sulphonylurea group. Treatment satisfaction was comparable across the treatment groups. There were no episodes of severe hypoglycaemia in either group, however, self‐recorded episodes of blood glucose ≤3.9 mmol/l were significantly lower with liraglutide (incidence rate ratio 0.29, 95% CI 0.19, 0.41, p < 0.0001).

Conclusions

Liraglutide compared with sulphonylurea is well tolerated and maybe an effective therapy in combination with metformin during Ramadan with more patients able to achieve target HbA1c, lose or maintain weight with no severe hypoglycaemia. This was achieved with a high level of treatment satisfaction.
Evaluation of Atrial Electromechanical Delay and Its Relationship to Inflammation and Oxidative Stress in Patients with Chronic Obstructive Pulmonary Disease
Authors: Acar Gurkan , Kahraman Hasan , Akkoyun Murat , Kilinc Metin , Zencir Cemil , Yusufoglu Edagani , Dirnak Imran , Sahin Hatice , Olmez Soner , Akcay Ahmet , Ardic Idris
Published: December 2013

Objectives

The aims of this study were to evaluate atrial electromechanical delay, inflammation, and oxidative stress parameters, along with to investigate clinical and laboratory characteristics affecting atrial electromechanical delay in patients with chronic obstructive pulmonary disease (COPD).

Methods

Forty‐three patients with COPD (60.5 ± 9.9 years) and 50 healthy controls (59.6 ± 7.1 years) were included in the study. Atrial electromechanical delay intervals were measured from lateral mitral annulus corrected PA (cPA lateral) and lateral tricuspid annulus (cPA tricuspid) using tissue Doppler imaging (TDI), and corrected for heart rate. Left and right ventricles functions were examined using conventional and TDI. Plasma levels of high‐sensitive C‐reactive protein (hsCRP) and oxidative stress parameters were also measured. Factors associated with atrial electromechanical delay were evaluated by stepwise multiple regression analysis.

Results

Corrected PA lateral and cPA tricuspid were significantly higher in patients with COPD (69.8 ± 10.4 vs. 62.2 ± 8.9 msec, P < 0.001 and 45.4 ± 10.2 vs. 33.5 ± 5.1 msec, P < 0.001, respectively). Plasma levels of hsCRP and malondialdehyde, an indicator of oxidative stress, were increased in patient's group (15.7 ± 31.7 vs. 4.8 ± 4.7 mg/L, P = 0.01 and 17.1 ± 10.3 vs. 11.6 ± 7.9 nmol/L, P = 0.005, respectively). cPA lateral is independently related to lateral Em/Am ratio (β = −0.29, P = 0.004) and forced expiratory volume in 1st second/forced vital capacity (FEV1/FVC) ratio (β = −0.24, P = 0.02). cPA tricuspid is independently related to only FEV1/FVC ratio (β = −0.51, P < 0.001).

Conclusions

This study shows that atrial electromechanical delay intervals are prolonged in patients with COPD. Prolongation of atrial electromechanical delay measured from lateral tricuspid annulus was independently related with FEV1/FVC ratio in these patients.
Does Accessory Pathway Significantly Alter Left Ventricular Twist/Torsion? A Study in Wolff‐Parkinson‐White Syndrome by Velocity Vector Imaging
Authors: Aminian Farimah , Esmaeilzadeh Maryam , Moladoust Hassan , Maleki Majid , Shahrzad Soraya , Emkanjoo Zahra , Sadeghpour Anita
Published: December 2013

Background

The aim of this study was to determine the impact of manifest accessory pathway on left ventricle (LV) twist physiology in Wolff‐Parkinson‐White (WPW) patients. Although this issue was addressed in 1 study based on speckle tracking method, there was no comparative study with a different technique. We planned to use velocity vector imaging (VVI) to find out how much an accessory pathway can affect LV twist mechanics.

Methods

Thirty patients were enrolled regarding inclusion and exclusion criteria. Two serial comprehensive transthoracic echocardiography evaluations were performed before and after radiofrequency catheter ablation (RFCA) within 24 hours. Stored cine loops were analyzed using VVI technique and LV twist and related parameters were extracted.

Results

Comparing pre‐ and post‐RFCA data, no significant changes were observed in LV systolic and diastolic dimensions, LV ejection fraction (LVEF), and Doppler and tissue Doppler‐related parameters. VVI study revealed remarkable rise in peak LV apical rotation (10.3º ± 3.0º to 13.8º ± 3.6º, P < 0.001) and basal rotation (−6.0 ± 1.8º to −7.7 ± 1.8º, P < 0.001) after RFCA. Subsequently LV twist showed a surge from 14.7º ± 3.9º to 20.2º ± 4.4º (P < 0.001). LV untwisting rate changed significantly from −96 ± 67 to −149.0 ± 47.5°/sec (P < 0.001) and apical‐basal rotation delay showed a remarkable decline after RFCA (106 ± 81 vs. 42.8 ± 26.0 msec, P < 0.001).

Conclusion

Accessory pathways have a major impact on LV twist mechanics.
Epicardial Adipose Tissue Thickness in Hemodialysis Patients
Authors: Altun Burak , Tasolar Hakan , Eren Necmi , Binnetoğlu Emine , Altun Mehzat , Temiz Ahmet , Gazi Emine , Barutcu Ahmet , Altunoren Orcun , Colkesen Yucel , Uysal Fatma
Published: December 2013

Aim

Hemodialysis (HD) patients had higher cardiovascular mortality and it is related to atherosclerosis. Epicardial adipose tissue (EAT) thickness is a marker of atherosclerosis and independent predictor of coronary artery disease. The aim of our study was to evaluate the relationship between EAT and carotid intima‐media thickness (CIMT) predictors of early atherosclerosis in HD patients.

Methods

The study included 62 HD patients and 40 healthy controls. EAT thickness and CIMT were measured by echocardiography in all subjects.

Results

Epicardial adipose tissue thickness and CIMT were higher (6.98 ± 1.67 vs. 3.84 ± 0.73 mm, P < 0.001, 0.94 ± 0.17 vs. 0.63 ± 0.11 mm, P < 0.001, respectively) in HD patients than in control subjects. EAT thickness were correlated with CIMT, HD duration, age, and calcium. In addition, HD duration, CIMT, and age were independent predictors of EAT thickness on HD patients in regression analysis.

Conclusion

Epicardial adipose tissue thickness may be a useful indicator of early atherosclerosis in HD patients.
Figural fluency and immediate visual memory in patients with at‐risk mental state for psychosis: empirical study
Authors: Pawełczyk Agnieszka , Kotlicka‐Antczak Magdalena , Rabe‐Jabłońska Jolanta , Pawełczyk Tomasz , Ruszpel Anna , Łojek Emila
Published: December 2013

Aim

Although a number of cognitive functions have been assessed in the ultra‐high risk (UHR) population, only one study has reported on figural fluency. Visual memory was measured by different tests providing inconsistent results. The aim of the present study was to compare figural fluency and visual immediate memory performance in UHR patients and normal subjects.

Methods

The UHR sample consisted of 55 help‐seeking individuals meeting CAARMS criteria. The control group consisted of 65 subjects. They were matched as a group by age, gender and education level. Figural fluency (RFFT) and immediate visual memory (BVRT) were assessed within 2 weeks after inclusion in the study in the UHR patient group.

Results

Significant differences were obtained in RFFT and BVRT results. In BVRT, UHR patients scored lower in number of correct designs (P < 0.001) and higher in number of errors (P < 0.0001), especially omissions (P < 0.001) and distortions (P < 0.0001). UHR subjects accurately recalled fewer designs, omitted and distorted more test figures. In RFFT, they scored lower in production of novel designs (P < 0.0001) and higher in the error ratio index (P < 0.008). They produced fewer novel designs and made more preservative errors.

Conclusions

The current study concerns non‐verbal cognitive functions in UHR samples. Our results suggest that figural fluency and visual immediate memory are impaired in help‐seeking UHR individuals as compared with matched controls.
Epidemiology of myelofibrosis, essential thrombocythemia, and polycythemia vera in the European Union
Authors: Moulard Odile , Mehta Jyotsna , Fryzek Jon , Olivares Robert , Iqbal Usman , Mesa Ruben A.
Published: December 2013

Background

Primary myelofibrosis (PMF), essential thrombocythemia (ET), and polycythemia vera (PV) are BCR ABL‐negative myeloproliferative neoplasms (MPN). Published epidemiology data are scarce, and multiple sources are needed to assess the disease burden.

Methods

We assembled the most recent information available on the incidence and prevalence of myelofibrosis (MF), ET, and PV by conducting a structured and exhaustive literature review of the published peer‐reviewed literature in EMBASE and by reviewing online documentation from disease registries and relevant health registries in European countries. The search was restricted to human studies written in English or French and published between January 1, 2000, and December 6, 2012.

Results

Eleven articles identified from EMBASE, three online hematology or oncology registries, and two Web‐based databases or reports were used to summarize epidemiological estimates for MF, PV, and ET. The incidence rate of MF ranged from 0.1 per 100 000 per year to 1 per 100 000 per year. Among the various registries, the incidence of PV ranged from 0.4 per 100 000 per year to 2.8 per 100 000 per year, while the literature estimated the range of PV incidence to be 0.68 per 100 000 to 2.6 per 100 000 per year. The estimated incidence of ET was between 0.38 per 100 000 per year and 1.7 per 100 000 per year. While a few studies reported on the MPNs' prevalences, it is difficult to compare them as various types of prevalence were calculated (point prevalence vs. period prevalence) and standardization was made according to different populations (e.g., the world population and the European population).

Conclusion

There is a wide variation in both prevalence and incidence estimates observed across European data sources. Carefully designed studies, with standardized definitions of MPNs and complete ascertainment of patients including both primary and secondary MFs, should be conducted so that estimates of the population aimed to receive novel treatments for these neoplasms are better understood assist public health planning and provide valuable information about the burden of illness to policy makers, funding agencies, resource planners, healthcare insurers, and pharmaceutical manufacturers.