Patch clamp protocols to study ion channel activity in microglia.

Microglia express a variety of ion channels, which can be distinguished based on their ion selectivity into K(+), H(+), Na(+), Ca(2+), nonselective cation, and Cl(-) channels. With respect to their activation mode, voltage-, Ca(2+)-, calcium release-, G protein-, swelling-, and stretch-activated ion channels have been described in microglia. The best method to study the activity of microglial ion channels is the patch clamp technique.

Fluorescence imaging of intracellular Ca2+, Na+, and H+ in cultured microglia.

The behavior of microglial cells involves the activity of a variety of ion channels and ion transporters, which are implicated in the regulation of ion concentrations, membrane potential, and cell volume of microglia. Fluorescence imaging has been proven to be an elegant method to study ion concentration changes in intact microglial cells under physiological and pathophysiological conditions. The development of highly specific ion indicators has made it possible to detect changes in intracellular Ca(2+), Na(+), and H(+) concentrations of microglial cells as a result of ion channel or ion transporter activity.

In vivo analysis of aquaporin 0 function in zebrafish: permeability regulation is required for lens transparency.

Purpose: The zebrafish lens is well suited for studies of physiology and development due to its rapid formation in the embryo and genetic accessibility. Aquaporin 0 (AQP0), a lens-specific membrane protein, is required for lens clarity. Zebrafish have two copies of AQP0 (Aqp0a and b), whereas mammals have a single, multifunctional protein.

Object tracking in motion-blind flies.

Different visual features of an object, such as its position and direction of motion, are important elements for animal orientation, but the neural circuits extracting them are generally not well understood. We analyzed this problem in Drosophila, focusing on two well-studied behaviors known as optomotor response and fixation response. In the neural circuit controlling the optomotor response, columnar T4 and T5 cells are thought to be crucial.

Darkfield adapter for whole slide imaging: adapting a darkfield internal reflection illumination system to extend WSI applications.

We present a new method for whole slide darkfield imaging. Whole Slide Imaging (WSI), also sometimes called virtual slide or virtual microscopy technology, produces images that simultaneously provide high resolution and a wide field of observation that can encompass the entire section, extending far beyond any single field of view. For example, a brain slice can be imaged so that both overall morphology and individual neuronal detail can be seen.

Ring Finger Protein 14 is a new regulator of TCF/β-catenin-mediated transcription and colon cancer cell survival.

T-cell factor/lymphoid enhancer factor (TCF/LEF) proteins regulate transcription by recruiting β-catenin and its associated co-regulators. Whether TCF/LEFs also recruit more factors through independent, direct interactions is not well understood. Here we discover Ring Finger Protein 14 (RNF14) as a new binding partner for all TCF/LEF transcription factors.

The immune response to one-lung-ventilation is not affected by repeated alveolar recruitment manoeuvres in pigs.

Background: Acute lung injury after thoracic surgery relates to alveolar inflammation induced by one-lung ventilation (OLV) and surgical manipulation. However, alveolar recruitment manoeuvres (ARM), conventional ventilation, and airway manipulation may increase alveolar trauma. This study evaluates pulmonary immune effects of these co-factors in a porcine model.

For whom the bell (curve) tolls: cortisol rapidly affects memory retrieval by an inverted U-shaped dose-response relationship.

Stress and cortisol are generally considered to impair declarative memory retrieval, although opposite results have also been reported. Dose-dependent effects and differences between genomic and non-genomic cortisol effects are possible reasons for these discrepancies. The aim of the current experiment was to assess the non-genomic effects of escalating doses of intravenous cortisol on cued recall of socially relevant information in humans.

Free Energies by Thermodynamic Integration Relative to an Exact Solution, Used to Find the Handedness-Switching Salt Concentration for DNA.

Sets of free energy differences are useful for finding the equilibria of chemical reactions, while absolute free energies have little physical meaning. However finding the relative free energy between two macrostates by subtraction of their absolute free energies is a valuable strategy in certain important cases. We present calculations of absolute free energies of biomolecules, using a combination of the well-known Einstein molecule method (for treating the solute) with a conceptually related method of recent genesis for computing free energies of liquids (to treat the solvent and counterions).

Dynamics and precision in retinoic acid morphogen gradients.

Retinoic acid (RA) regulates many cellular behaviors during embryonic development and adult homeostasis. Like other morphogens, RA forms gradients through the use of localized sources and sinks, feedback, and interactions with other signals; this has been particularly well studied in the context of hindbrain segmentation in vertebrate embryos. Yet, as a small lipophilic molecule derived from a dietary source-vitamin A-RA differs markedly from better-studied polypeptide morphogens in its mechanisms of transport, signaling, and removal.

Effects of phytoestrogens and other plant-derived compounds on mesenchymal stem cells, bone maintenance and regeneration.

Phytoestrogens and other plant-derived compounds and extracts have been developed for the treatment of menopause-related complaints and disorders, e.g. hot flushes and osteoporosis.

Morphogenesis and cell fate determination within the adaxial cell equivalence group of the zebrafish myotome.

One of the central questions of developmental biology is how cells of equivalent potential-an equivalence group-come to adopt specific cellular fates. In this study we have used a combination of live imaging, single cell lineage analyses, and perturbation of specific signaling pathways to dissect the specification of the adaxial cells of the zebrafish embryo. We show that the adaxial cells are myogenic precursors that form a cell fate equivalence group of approximately 20 cells that consequently give rise to two distinct sub-types of muscle fibers: the superficial slow muscle fibers (SSFs) and muscle pioneer cells (MPs), distinguished by specific gene expression and cell behaviors.

The transcriptional profile of mesenchymal stem cell populations in primary osteoporosis is distinct and shows overexpression of osteogenic inhibitors.

Primary osteoporosis is an age-related disease characterized by an imbalance in bone homeostasis. While the resorptive aspect of the disease has been studied intensely, less is known about the anabolic part of the syndrome or presumptive deficiencies in bone regeneration. Multipotent mesenchymal stem cells (MSC) are the primary source of osteogenic regeneration.

Noise drives sharpening of gene expression boundaries in the zebrafish hindbrain.

Morphogens provide positional information for spatial patterns of gene expression during development. However, stochastic effects such as local fluctuations in morphogen concentration and noise in signal transduction make it difficult for cells to respond to their positions accurately enough to generate sharp boundaries between gene expression domains. During development of rhombomeres in the zebrafish hindbrain, the morphogen retinoic acid (RA) induces expression of hoxb1a in rhombomere 4 (r4) and krox20 in r3 and r5.

Description of hard-sphere crystals and crystal-fluid interfaces: a comparison between density functional approaches and a phase-field crystal model.

In materials science the phase-field crystal approach has become popular to model crystallization processes. Phase-field crystal models are in essence Landau-Ginzburg-type models, which should be derivable from the underlying microscopic description of the system in question. We present a study on classical density functional theory in three stages of approximation leading to a specific phase-field crystal model, and we discuss the limits of applicability of the models that result from these approximations.

Connectivity percolation in suspensions of hard platelets.

We present a study on connectivity percolation in suspensions of hard platelets by means of Monte Carlo simulation. We interpret our results using a contact-volume argument based on an effective single-particle cell model. It is commonly assumed that the percolation threshold of anisotropic objects scales as their inverse aspect ratio.

The effect of systematic clinical interventions with cigarette smokers on quit status and the rates of smoking-related primary care office visits.

Background: The United States Public Health Service (USPHS) Guideline for Treating Tobacco Use and Dependence includes ten key recommendations regarding the identification and the treatment of tobacco users seen in all health care settings. To our knowledge, the impact of system-wide brief interventions with cigarette smokers on smoking prevalence and health care utilization has not been examined using patient population-based data.

Methods And Findings: Data on clinical interventions with cigarette smokers were examined for primary care office visits of 104,639 patients at 17 Harvard Vanguard Medical Associates (HVMA) sites.

Remote ischaemic preconditioning for heart surgery. The study design for a multi-center randomized double-blinded controlled clinical trial--the RIPHeart-Study.

Aims: Transient ischaemia of non-vital tissue has been shown to enhance the tolerance of remote organs to cope with a subsequent prolonged ischaemic event in a number of clinical conditions, a phenomenon known as remote ischaemic preconditioning (RIPC). However, there remains uncertainty about the efficacy of RIPC in patients undergoing cardiac surgery. The purpose of this report is to describe the design and methods used in the "Remote Ischaemic Preconditioning for Heart Surgery (RIPHeart)-Study".

Cellular retinoic acid-binding proteins are essential for hindbrain patterning and signal robustness in zebrafish.

The vitamin A derivative retinoic acid (RA) is a morphogen that patterns the anterior-posterior axis of the vertebrate hindbrain. Cellular retinoic acid-binding proteins (Crabps) transport RA within cells to both its nuclear receptors (RARs) and degrading enzymes (Cyp26s). However, mice lacking Crabps are viable, suggesting that Crabp functions are redundant with those of other fatty acid-binding proteins.

Tunneling conductivity in composites of attractive colloids.

In conductor-insulator nanocomposites in which conducting fillers are dispersed in an insulating matrix, the electrical connectedness is established by inter-particle tunneling or hopping processes. These systems are intrinsically non-percolative and a coherent description of the functional dependence of the conductivity σ on the filler properties, and in particular of the conductor-insulator transition, requires going beyond the usual continuum percolation approach by relaxing the constraint of a fixed connectivity distance. In this article, we consider dispersions of conducting spherical particles which are connected to all others by tunneling conductances and which are subjected to an effective attractive square-well potential.

Depletion of the receptor for advanced glycation end products (RAGE) sensitizes towards apoptosis via p53 and p73 posttranslational regulation.

The receptor for advanced glycation endproduct (RAGE) is involved in diabetic complications and chronic inflammation, conditions known to affect the sensitivity towards apoptosis. Here, we studied the effect of genetically depleting RAGE on the susceptibility towards apoptosis. In murine osteoblastic cells, RAGE knockout increased both spontaneous and induced apoptosis.

[The contradictory contexts of interdisciplinarity].

The benefits of interdisciplinary approaches in patient care, research and education are quite obvious and set the trend for more interdisciplinary structures. In order to achieve sustained success, however, there are numerous risks of interdisciplinary collaboration that have to be considered. Interdisciplinarity leads to an increasing degree of specialization and consequently to a greater experience of specialists in highly specific procedures.

On the influence of a patterned substrate on crystallization in suspensions of hard spheres.

We present a computer simulation study on crystal nucleation and growth in supersaturated suspensions of mono-disperse hard spheres induced by a triangular lattice substrate. The main result is that compressed substrates are wet by the crystalline phase (the crystalline phase directly appears without any induction time), while for stretched substrates we observe heterogeneous nucleation. The shapes of the nucleated crystallites fluctuate strongly.

Bmp signaling exerts opposite effects on cardiac differentiation.

Rationale: The importance for Bmp signaling during embryonic stem cell differentiation into myocardial cells has been recognized. The question when and where Bmp signaling in vivo regulates myocardial differentiation has remained largely unanswered.

Objective: To identify when and where Bmp signaling regulates cardiogenic differentiation.