bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrochemical nucleic acid-based biosensors: Concepts, terms, and methodology (IUPAC Technical Report)
Authors: Labuda Jan , Brett Ana Maria Oliveira , Evtugyn Gennady , Fojta Miroslav , Mascini Marco , Ozsoz Mehmet , Palchetti Ilaria , Paleček Emil , Wang Joseph
Published: April 2010

An electrochemical nucleic acid (NA)-based biosensor is a biosensor that integrates a nucleic acid as the biological recognition element and an electrode as the electrochemical signal transducer. The present report provides concepts, terms, and methodology related to biorecognition elements, detection principles, type of interactions to be addressed, and construction and performance of electrochemical NA biosensors, including their critical evaluation, which should be valuable for a wide audience, from academic, biomedical, environmental, and food-testing, drug-developing, etc. laboratories to sensor producers.
Empirical and theoretical models of equilibrium and non-equilibrium transition temperatures of supplemented phase diagrams in aqueous systems (IUPAC Technical Report)
Authors: Corti Horacio R. , Angell C. Austen , Auffret Tony , Levine Harry , Buera M. Pilar , Reid David S. , Roos Yrjö H. , Slade Louise
Published: April 2010

This paper describes the main thermodynamic concepts related to the construction of supplemented phase (or state) diagrams (SPDs) for aqueous solutions containing vitrifying agents used in the cryo- and dehydro-preservation of natural (foods, seeds, etc.) and synthetic (pharmaceuticals) products. It also reviews the empirical and theoretical equations employed to predict equilibrium transitions (ice freezing, solute solubility) and non-equilibrium transitions (glass transition and the extrapolated freezing curve). The comparison with experimental results is restricted to carbohydrate aqueous solutions, because these are the most widely used cryoprotectant agents. The paper identifies the best standard procedure to determine the glass transition curve over the entire water-content scale, and how to determine the temperature and concentration of the maximally freeze-concentrated solution.
Evaluating laboratory diagnostic tests and translational research
Authors: Plebani Mario
Published: April 2010

In laboratory medicine, the evaluation of an assay is reasonably straightforward and allows broad applicable standards to be established. In contrast, the evaluation of a test is more complex and inherently less susceptible to standardization. The term “test” refers to the use of an assay in the context of a particular disease, in a particular population, and for a particular purpose. Therefore, the true evaluation is to demonstrate its effectiveness in helping a clinician achieve a correct diagnosis or improve patient clinical outcomes. The debate on the current weak framework used for evaluating laboratory tests has been stimulated by recent technological developments, in particular “omics” tests. Currently, consensus has been achieved concerning the proposal to use a model based on at least four steps to be investigated. These are analytical and clinical validity, clinical usefulness and, finally, any ethical, social and legal implications, including economic implications. As the pace of technological advancements in laboratory medicine accelerates, it is time to discuss the role of laboratory testing, and the related role of clinical laboratories. In particular, we should consider whether they should evolve as focused factories of numbers and results, or as knowledge services with an emphasis on improving appropriateness in test requesting, and the interpretation and utilization of laboratory information.

Clin Chem Lab Med 2010;48:983–8.
Clinical implication of plasma neutrophil gelatinase-associated lipocalin (NGAL) concentrations in patients with advanced carotid atherosclerosis
Authors: Giaginis Constantinos , Zira Athina , Katsargyris Athanasios , Klonaris Chris , Theocharis Stamatios
Published: April 2010

Background: Neutrophil gelatinase-associated lipocalin (NGAL) is well established as an early and specific biomarker of kidney disease. Recent evidence further suggests that NGAL may play a crucial role in vascular remodeling and plaque instability during the development of atherosclerosis.

Methods: Plasma NGAL concentrations measured using a solid-phase enzyme-linked immunosorbent assay (ELISA) were correlated with medical history, risk factors and medication intake in 141 patients with advanced carotid atherosclerotic lesions who underwent carotid endarterectomy for vascular repair.

Results: Plasma NGAL concentrations were associated with patient age (Rs=0.2055, p=0.0144), plasma homocysteine (Rs=0.4274, p<0.00001) and serum creatinine (Rs=0.4640, p<0.00001) concentrations and estimated glomerular filtration rate (eGFR) (Rs=−0.4911, p<0.00001). Hypertensive patients, as well as those receiving therapy with angiotensin converting enzyme (ACE) inhibitors, presented with significantly enhanced plasma NGAL concentrations when compared to normotensive (p=0.0341) patients and those not treated (p=0.0004). Enhanced NGAL concentrations did not meet statistical significance for patients with advanced stenosis grade (p=0.0971) or a history of peripheral artery disease (p=0.0827). Multiple regression analysis identified homocysteine, creatinine, eGFR and treatment with ACE inhibitors (p=0.0019, <0.00001, 0.0005 and 0.0219, respectively) as independent predictors of NGAL concentration.

Conclusions: Plasma NGAL concentrations were associated with patient age, hypertension, eGFR, creatinine and homocysteine concentrations and therapy with ACE inhibitors. The role of NGAL in the development of atherosclerosis needs to be further explored taking into consideration the uncontrolled effect of renal disease in atherosclerotic patients with multiple risk factors.

Clin Chem Lab Med 2010;48:1035–41.
Gesellschafterstreitigkeiten im Kapitalgesellschaftsrecht – Zur Perspektive der schiedsgerichtlichen Streitbeilegung
Authors: Saenger Ingo , Splittgerber Daniel
Published: April 2010

Schiedsverfahren werden immer bedeutsamer. Mehr denn je ist das Parteibestreben in Wirtschaftssachen festzustellen, die staatliche Gerichtsbarkeit weitgehend auszuschließen – droht das »Opting-Out« allgemeine Praxis zu werden? Die jüngste BGH-Entscheidung zur Schiedsfähigkeit von Beschlussmängelstreitigkeiten im GmbH-Recht (II ZR 255/08 vom 6.4.2009) gibt Anlass, einen Blick auf Gegenwart und Zukunft privater Streitbeilegung im Gesellschaftsrecht zu werfen. Insbesondere sollen die Möglichkeiten der Vereinbarung schiedsrichterlicher Zuständigkeiten untersucht werden, die GmbH- und Aktienrecht heute und künftig bieten können.
Naturalizing the unnatural: A view from blending theory
Authors: Fludernik Monika
Published: April 2010

In Towards a ‘Natural’ Narratology (Fludernik, Routledge, 1996), I presented the process of naturalization as a strategy of converting not-naturally-occurring storytelling scenarios into familiarized models of narration. In order to map this process, this paper resorts to the most recent version of blending theory (conceptual integration networks) as proposed by Mark Turner and Gilles Fauconnier. The analysis will be prefaced by a few framing remarks on the cognitive approach in the study of narrative and will conclude with an outlook on further possible applications of blending theory.
Causal attribution and the analysis of literary characters: A. C. Bradley's study of Iago and Othello
Authors: Arenas Enrique Cámara
Published: April 2010

A. C. Bradley's approach to character-construal in Shakespearean Tragedy (MacMillan, 1904) has often been regarded as a good example of the humanizing approach to literary characters. His lectures on Iago, Othello or Macbeth have been criticized by other scholars for a number of reasons, but particularly for using premises and facts in his argumentation which are not found in the plays. Bradley's task is in many senses an example of person perception, which he performs without alluding to any social psychological theories or methods. In the present article I revise Bradley's reasoning in the light of Kelley's Covariance Theory of Causal Attribution, in an attempt both to re-evaluate Bradley's procedures and, especially, to determine ways in which social psychology might provide literary critics with valuable tools and insights.
Cullin 5 Regulates Cortical Layering by Modulating the Speed and Duration of Dab1-Dependent Neuronal Migration
Authors: Simó Sergi , Jossin Yves , Cooper Jonathan A.
Published: April 2010

The multilayered mammalian neocortex develops by the coordinated immigration and differentiation of cells that are produced at distant sites. Correct layering requires an extracellular protein, Reelin (Reln), an intracellular signaling molecule, Disabled-1 (Dab1), and an E3 ubiquitin ligase, Cullin-5 (Cul5). Reln activates Dab1, which is then degraded by Cul5. Here we test whether Cul5 regulates neuron layering by affecting Dab1 stability or other mechanisms. We find that a stabilized mutant Dab1, which resists Cul5-dependent degradation, causes a similar phenotype to Cul5 deficiency. Moreover, Cul5 has no effect when Dab1 is absent. The effects of Cul5 and Dab1 are cell autonomous, and Cul5 regulates movement of early as well as late cortical neurons. Removing Cul5 increases the speed at which neurons migrate through the cortical plate by reducing the time spent stationary and increasing the speed of individual steps. These results show that Cul5 regulates neuron layering by stimulating Dab1 degradation and that Cul5 controls migration speed and stopping point, and they demonstrate the importance of negative feedback in signaling during cortical development.
Inwardly Permeating Na Ions Generate the Voltage Dependence of Resurgent Na Current in Cerebellar Purkinje Neurons
Authors: Aman Teresa K. , Raman Indira M.
Published: April 2010

Voltage-gated Na channels of cerebellar Purkinje neurons express an endogenous open-channel blocking protein. This blocker binds channels at positive potentials and unbinds at negative potentials, generating a resurgent Na current and permitting rapid firing. The macroscopic voltage dependence of resurgent current raises the question of whether the blocker directly senses membrane potential or whether voltage dependence is conferred indirectly. Because we previously found that inwardly permeating Na ions facilitate dissociation of the blocker, we measured voltage-clamped currents in different Na gradients to test the role of permeating ions in generating the voltage dependence of unblock. In reverse gradients, outward resurgent currents were tiny or absent, suggesting that unblock normally requires “knockoff” by Na. Inward resurgent currents at strongly negative potentials, however, were larger in reverse than in control gradients. Moreover, occupancy of the blocked state was prolonged both in reverse gradients and in control gradients with reduced Na concentrations, indicating that block is more stable when inward currents are small. Accordingly, reverse gradients shifted the voltage dependence of block, such that resurgent currents were evoked even after conditioning at negative potentials. Additionally, in control gradients, peak resurgent currents decreased linearly with driving force during the conditioning step, suggesting that the stability of block varies directly with inward Na current amplitude. Thus, the voltage dependence of blocker unbinding results almost entirely from repulsion by Na ions occupying the external pore. The lack of voltage sensitivity of the blocking protein suggests that the blocker's binding site lies outside the membrane field, in the permeation pathway.
Disrupted Transforming Growth Factor-β Signaling in Spinal and Bulbar Muscular Atrophy
Authors: Katsuno Masahisa , Adachi Hiroaki , Minamiyama Makoto , Waza Masahiro , Doi Hideki , Kondo Naohide , Mizoguchi Hiroyuki , Nitta Atsumi , Yamada Kiyofumi , Banno Haruhiko , Suzuki Keisuke , Tanaka Fumiaki , Sobue Gen
Published: April 2010

Spinal and bulbar muscular atrophy (SBMA) is a late-onset lower motor neuron disease caused by the expansion of a trinucleotide CAG repeat, which encodes a polyglutamine tract in androgen receptor (AR). Although it is commonly held that the pathogenic polyglutamine proteins accumulate in neurons and thereby induce transcriptional dysregulation, the downstream molecular events have remained elusive. Here, we examined whether TGF-β signaling is dysregulated in SBMA. Nuclear translocation of phosphorylated Smad2/3, a key step in TGF-β signaling, is suppressed in the spinal motor neurons of male transgenic mice carrying the mutant humanAR. A similar finding was also observed in the motor neurons, but not in Purkinje cells, of SBMA patients. The pathogenic AR, the causative protein of SBMA, inhibits the transcription of TGF-β receptor type II (TβRII) via abnormal interactions with NF-Y and p300/CBP-associated factor. Furthermore, overexpression of TβRII dampens polyglutamine-induced cytotoxicity in a neuroblastoma cell line expressing the pathogenic AR. The present study thus indicates that disruption of TGF-β due to the transcriptional dysregulation of TβRII is associated with polyglutamine-induced motor neuron damage in SBMA.
Evidence from Computer Simulations for Alterations in the Membrane Biophysical Properties and Dendritic Processing of Synaptic Inputs in Mutant Superoxide Dismutase-1 Motoneurons
Authors: ElBasiouny Sherif M. , Amendola Julien , Durand Jacques , Heckman C. J.
Published: April 2010

A critical step in improving our understanding of the development of amyotrophic lateral sclerosis (ALS) is to identify the factors contributing to the alterations in the excitability of motoneurons and assess their individual contributions. Here we investigated the early alterations in the passive electrical and morphological properties of neonatal spinal motoneurons that occur by 10 d after birth, long before disease onset. We identified some of the factors contributing to these alterations, and estimated their individual contributions. To achieve this goal, we undertook a computer simulation analysis using realistic morphologies of reconstructed wild-type (WT) and mutant superoxide dismutase-1 (mSOD1) motoneurons. Ion channel parameters of these models were then tuned to match the experimental data on electrical properties obtained from these same motoneurons. We found that the reduced excitability ofmSOD1models was accompanied with decreased specific membrane resistance by ∼25% and efficacy of synaptic inputs (slow and fast) by 12–22%. Linearity of summation of synaptic currents was similar toWT. We also assessed the contribution of the alteration in dendritic morphology alone to this decreased excitability and found that it reduced the input resistance by 10% and the efficacy of synaptic inputs by 7–15%. Our results were also confirmed in models with dendritic active conductances. Our simulations indicated that the alteration in passive electrical properties ofmSOD1models resulted from concurrent alterations in their morphology and membrane biophysical properties, and consequently altered the motoneuronal dendritic processing of synaptic inputs. These results clarify new aspects of spinal motoneurons malfunction in ALS.
High-Frequency Network Activity, Global Increase in Neuronal Activity, and Synchrony Expansion Precede Epileptic SeizuresIn Vitro
Authors: Jiruska Premysl , Csicsvari Jozsef , Powell Andrew D. , Fox John E. , Chang Wei-Chih , Vreugdenhil Martin , Li Xiaoli , Palus Milan , Bujan Alejandro F. , Dearden Richard W. , Jefferys John G. R.
Published: April 2010

How seizures start is a major question in epilepsy research. Preictal EEG changes occur in both human patients and animal models, but their underlying mechanisms and relationship with seizure initiation remain unknown. Here we demonstrate the existence, in the hippocampal CA1 region, of a preictal state characterized by the progressive and global increase in neuronal activity associated with a widespread buildup of low-amplitude high-frequency activity (HFA) (>100 Hz) and reduction in system complexity. HFA is generated by the firing of neurons, mainly pyramidal cells, at much lower frequencies. Individual cycles of HFA are generated by the near-synchronous (within ∼5 ms) firing of small numbers of pyramidal cells. The presence of HFA in the low-calcium model implicates nonsynaptic synchronization; the presence of very similar HFA in the high-potassium model shows that it does not depend on an absence of synaptic transmission. Immediately before seizure onset, CA1 is in a state of high sensitivity in which weak depolarizing or synchronizing perturbations can trigger seizures. Transition to seizure is characterized by a rapid expansion and fusion of the neuronal populations responsible for HFA, associated with a progressive slowing of HFA, leading to a single, massive, hypersynchronous cluster generating the high-amplitude low-frequency activity of the seizure.
Enhanced Endocannabinoid Signaling Elevates Neuronal Excitability in Fragile X Syndrome
Authors: Zhang Longhua , Alger Bradley E.
Published: April 2010

Fragile X syndrome (FXS) results from deficiency of fragile X mental retardation protein (FMRP). FXS is the most common heritable form of mental retardation, and is associated with the occurrence of seizures. Factors responsible for initiating FXS-related hyperexcitability are poorly understood. Many protein-synthesis-dependent functions of group I metabotropic glutamate receptors (Gp1 mGluRs) are exaggerated in FXS. Gp1 mGluR activation can mobilize endocannabinoids (eCBs) in the hippocampus and thereby increase excitability, but whether FMRP affects eCBs is unknown. We studied Fmr1 knock-out (KO) mice lacking FMRP to test the hypothesis that eCB function is altered in FXS. Whole-cell evoked IPSCs (eIPSCs) and field potentials were recorded in the CA1 region of acute hippocampal slices. Three eCB-mediated responses were examined: depolarization-induced suppression of inhibition (DSI), mGluR-initiated eCB-dependent inhibitory short-term depression (eCB-iSTD), and eCB-dependent inhibitory long-term depression (eCB-iLTD). Low concentrations of a Gp1 mGluR agonist produced larger eCB-mediated responses in Fmr1 KO mice than in wild-type (WT) mice, without affecting DSI. Western blots revealed that levels of mGluR1, mGluR5, or cannabinoid receptor (CB1R) were unchanged in Fmr1 KO animals, suggesting that the coupling between mGluR activation and eCB mobilization was enhanced by FMRP deletion. The increased susceptibility of Fmr1 KO slices to eCB-iLTD was physiologically relevant, since long-term potentiation of EPSP–spike (E–S) coupling induced by the mGluR agonist was markedly larger in Fmr1 KO mice than in WT animals. Alterations in eCB signaling could contribute to the cognitive dysfunction associated with FXS.
A Missense Mutation of the Gene Encoding Voltage-Dependent Sodium Channel (Nav1.1) Confers Susceptibility to Febrile Seizures in Rats
Authors: Mashimo Tomoji , Ohmori Iori , Ouchida Mamoru , Ohno Yukihiro , Tsurumi Toshiko , Miki Takafumi , Wakamori Minoru , Ishihara Shizuka , Yoshida Takashi , Takizawa Akiko , Kato Megumi , Hirabayashi Masumi , Sasa Masashi , Mori Yasuo , Serikawa Tadao
Published: April 2010

Although febrile seizures (FSs) are the most common convulsive syndrome in infants and childhood, the etiology of FSs has remained unclarified. Several missense mutations of the Nav1.1 channel (SCN1A), which alter channel properties, have been reported in a familial syndrome of GEFS+ (generalized epilepsy with febrile seizures plus). Here, we generatedScn1a-targeted rats carrying a missense mutation (N1417H) in the third pore region of the sodium channel by gene-driven ENU (N-ethyl-N-nitrosourea) mutagenesis. Despite their normal appearance under ordinary circumstances,Scn1amutant rats exhibited remarkably high susceptibility to hyperthermia-induced seizures, which involve generalized clonic and/or tonic–clonic convulsions with paroxysmal epileptiform discharges. Whole-cell patch-clamp recordings from HEK cells expressing N1417H mutant channels and from hippocampal GABAergic interneurons of N1417H mutant rats revealed a significant shift of the inactivation curve in the hyperpolarizing direction. In addition, clamp recordings clearly showed the reduction in action potential amplitude in the hippocampal interneurons of these rats. These findings suggest that a missense mutation (N1417H) of the Nav1.1 channel confers susceptibility to FS and the impaired biophysical properties of inhibitory GABAergic neurons underlie one of the mechanisms of FS.
The Phosphoinositide 3-Phosphatase MTMR2 Interacts with PSD-95 and Maintains Excitatory Synapses by Modulating Endosomal Traffic
Authors: Lee Hyun Woo , Kim Youngrim , Han Kihoon , Kim Hyun , Kim Eunjoon
Published: April 2010

MTMR2 is a 3-phosphatase specific for the phosphoinositides PI(3)P and PI(3,5)P2, which are mainly present on endosomes. Mutations in the MTMR2 gene in Schwann cells lead to a severe demyelinating peripheral neuropathy known as Charcot-Marie-Tooth disease type 4B1. MTMR2 expression is also detected in peripheral and central neurons, but neural functions of MTMR2 remain unclear. Here, we report that MTMR2 is localized to excitatory synapses of central neurons via direct interaction with PSD-95, a postsynaptic scaffolding protein abundant at excitatory synapses. Knockdown of MTMR2 in cultured neurons markedly reduces excitatory synapse density and function. This effect is rescued by wild-type MTMR2 but not by a mutant MTMR2 lacking PSD-95 binding or 3-phosphatase activity. MTMR2 knockdown leads to a decrease in the intensity of EEA1-positive early endosomes in dendrites but increases the intensity in the cell body region. Moreover, MTMR2 suppression promotes endocytosis, but not recycling, of the GluR2 subunit of AMPA receptors, which is an endosomal cargo. In addition, colocalization of internalized GluR2 with Lamp1-positive late endosomes/lysosomes is enhanced in the cell body area but not in dendrites. These results suggest that PSD-95-interacting MTMR2 contributes to the maintenance of excitatory synapses by inhibiting excessive endosome formation and destructive endosomal traffic to lysosomes.
Attentional Cueing at the Saccade Goal, Not at the Target Location, Facilitates Saccades
Authors: Khan Aarlenne Z. , Heinen Stephen J. , McPeek Robert M.
Published: April 2010

Presenting a behaviorally irrelevant cue shortly before a target at the same location decreases the latencies of saccades to the target, a phenomenon known as exogenous attention facilitation. It remains unclear whether exogenous attention interacts with early, sensory stages or later, motor planning stages of saccade production. To distinguish between these alternatives, we used a saccadic adaptation paradigm to dissociate the location of the visual target from the saccade goal. Three male and four female human subjects performed both control trials, in which saccades were made to one of two target eccentricities, and adaptation trials, in which the target was shifted from one location to the other during the saccade. This manipulation adapted saccades so that they eventually were directed to the shifted location. In both conditions, a behaviorally irrelevant cue was flashed 66.7 ms before target appearance at a randomly selected one of seven positions that included the two target locations. In control trials, saccade latencies were shortest when the cue was presented at the target location and increased with cue-target distance. In contrast, adapted saccade latencies were shortest when the cue was presented at the adapted saccade goal, and not at the visual target location. The dynamics of adapted saccades were also altered, consistent with prior adaptation studies, except when the cue was flashed at the saccade goal. Overall, the results suggest that attentional cueing facilitates saccade planning rather than visual processing of the target.
The ON Pathway Rectifies the OFF Pathway of the Mammalian Retina
Authors: Liang Zhiyin , Freed Michael A.
Published: April 2010

In the vertebrate visual system, ON cells respond to positive contrasts and OFF cells respond to negative contrasts, and thus both ON and OFF cells exhibit rectification. We investigated the retinal circuits by which the ON pathway rectifies the OFF pathway. White noise was projected onto anin vitropreparation of the mammalian retina and excitatory currents were recorded from retinal ganglion cells under whole-cell voltage clamp. Currents in OFF cells were more rectified than those in ON cells: thus, currents in ON cells were able to signal both positive and negative contrasts, but currents in OFF cells were virtually restricted to negative contrasts. Blocking signals in the ON pathway derectified currents in OFF ganglion cells, thus allowing them to be modulated by positive contrasts, indicating that the ON pathway normally rectifies currents in OFF ganglion cells. Such cross-rectification from ON to OFF pathways required intact glycinergic inhibition, indicating that a glycinergic amacrine cell, most likely the AII amacrine cell, allows the ON bipolar cell to hyperpolarize the OFF bipolar cell close to the threshold for transmitter release, thus rectifying excitatory currents in the OFF ganglion cell. Asymmetrical rectification of ON and OFF cells may be an adaptation to natural scenes that have more contrast levels below the mean than above. Thus, in order for ON and OFF pathways to encode an equal number of contrast levels, the ON cells must signal some negative contrasts.
Cotrafficking of SV2 and Synaptotagmin at the Synapse
Authors: Yao Jia , Nowack Amy , Kensel-Hammes Patricia , Gardner Richard G. , Bajjalieh Sandra M.
Published: April 2010

Synaptic vesicles are specialized cycling endosomes that contain a unique constellation of membrane proteins. Proteins are sorted to vesicles by short amino acid sequences that serve as binding sites for clathrin adaptor proteins. Here we show that a tyrosine-based endocytosis motif in the vesicle protein SV2 is required for trafficking to synaptic vesicles of both SV2 and the calcium sensor protein synaptotagmin. Aberrant neurotransmission in cultured hippocampal neurons lacking SV2 was rescued by expression of wild-type SV2A, but not by SV2A-Y46A, a mutant containing a disrupted endocytosis motif in SV2A's cytoplasmic N terminus. Neurons expressing SV2A-Y46A had significantly more SV2 on the plasma membrane, indicating reduced internalization. A screen for proteins that preferentially bound wild-type SV2A identified multiple endocytosis-related proteins, andin vitrobinding studies confirmed binding to the clathrin adaptors AP2, EPS15, and amphiphysin 2/Bin1. Neurons lacking SV2 contained less synaptotagmin and had a higher proportion of synaptotagmin on the plasma membrane. Expression of either wild-type SV2A or SV2A-Y46A restored synaptotagmin expression levels; however, only wild-type SV2A restored a normal proportion of synaptotagmin on the plasma membrane. These findings indicate that SV2 influences the expression and trafficking of synaptotagmin via separate mechanisms. Synaptic vesicles immunoisolated from SV2A/B double knock-out mice had significantly less synaptotagmin than vesicles isolated from wild-type mice. Our results indicate that SV2 plays a major role in regulating the amount of synaptotagmin in synaptic vesicles and provide an explanation for the observation that synapses lacking SV2 have fewer vesicles competent for calcium-induced fusion.
Selected SALM (Synaptic Adhesion-Like Molecule) Family Proteins Regulate Synapse Formation
Authors: Mah Won , Ko Jaewon , Nam Jungyong , Han Kihoon , Chung Woo Suk , Kim Eunjoon
Published: April 2010

Synaptic cell adhesion molecules regulate various steps of synapse formation. Despite the great diversity of neuronal synapses, relatively few adhesion molecules with synaptogenic activity have been identified. Synaptic adhesion-like molecules (SALMs) are members of a family of cell adhesion molecules known to regulate neurite outgrowth and synapse maturation; however, the role of SALMs in synapse formation remains unknown. We found that expression of the SALM family proteins SALM3 and SALM5 in nonneural and neural cells induces both excitatory and inhibitory presynaptic differentiation in contacting axons. SALM3 and SALM5 proteins are enriched in synaptic fractions, and form strong (SALM3) or weak (SALM5) complexes with postsynaptic density-95 (PSD-95), an abundant postsynaptic scaffolding protein at excitatory synapses. Aggregation of SALM3, but not SALM5, on dendritic surfaces induces clustering of PSD-95. Knockdown of SALM5 reduces the number and function of excitatory and inhibitory synapses. These results suggest that selected SALM family proteins regulate synapse formation, and that SALM3 and SALM5 may promote synapse formation through distinct mechanisms.
Presynaptic and Postsynaptic Mechanisms of Synaptic Plasticity and Metaplasticity during Intermediate-Term Memory Formation inAplysia
Authors: Antonov Igor , Kandel Eric R. , Hawkins Robert D.
Published: April 2010

Synaptic plasticity and learning involve different mechanisms depending on the following: (1) the stage of plasticity and (2) the history of plasticity, or metaplasticity. However, little is known about how these two factors are related. We have addressed that question by examining mechanisms of synaptic plasticity during short-term and intermediate-term behavioral sensitization and dishabituation in a semi-intact preparation of theAplysiasiphon-withdrawal reflex. Dishabituation differs from sensitization in that it is preceded by habituation, and is thus a paradigm for metaplasticity. We find that whereas facilitation during short-term sensitization by one tail shock involves presynaptic covalent modifications by protein kinase A (PKA) and CamKII, facilitation during intermediate-term sensitization by four shocks involves both presynaptic (PKA, CaMKII) and postsynaptic (Ca2+, CaMKII) covalent modifications, as well as both presynaptic and postsynaptic protein synthesis. The facilitation also involves presynaptic spike broadening 2.5 min after either one or four shocks, but not at later times. Dishabituation by four shocks differs from sensitization in several ways. First, it does not involve PKA or CaMKII, but rather involves presynaptic PKC. In addition, unlike sensitization with the same shock, dishabituation by four shocks does not involve protein synthesis or presynaptic spike broadening, and it also does not involve postsynaptic Ca2+. These results demonstrate that not only the mechanisms but also the site of plasticity depend on both the stage of plasticity and metaplasticity during memory formation.
SOCS3-Mediated Blockade of JAK/STAT3 Signaling Pathway Reveals Its Major Contribution to Spinal Cord Neuroinflammation and Mechanical Allodynia after Peripheral Nerve Injury
Authors: Dominguez Elisa , Mauborgne Annie , Mallet Jacques , Desclaux Mathieu , Pohl Michel
Published: April 2010

Neuropathic pain after peripheral nerve injury, associated with local neuroinflammation in the spinal cord, is a severe incapacitating condition with which clinical treatment remains challenging. Inflammatory molecules signal through various intracellular transduction pathways, activation of which may amplify and cause spreading of the inflammatory response. We showed recently that spinal nerve lesion leads to rapid activation of Janus kinase (JAK)/signal transducer and activator of transcription 3 (STAT3) signal transduction pathway in dorsal spinal cord microglia in relation with enhanced levels of spinal interleukin-6 (IL-6) protein. Here, we selectively inactivated JAK/STAT3 signaling in rat dorsal spinal cord glia through local, lentiviral-mediated production of the suppressor of cytokine signaling SOCS3, a physiologic inhibitory protein of JAK/STAT3, and analyzed its consequences in a preclinical model of neuropathic pain. The targeted blockade of JAK/STAT3 activity prevented the abnormal expression of IL-6, CC chemokine ligand CCL2, and activating transcription factor ATF3 induced in the spinal cord by chronic constriction injury of the sciatic nerve (CCI) and substantially attenuated mechanical hypersensitivity (allodynia) in rats. In naive rats, intrathecal administration of a proalgesic cytokine IL-6 rapidly activated microglial JAK/STAT3 and induced downstream changes closely resembling CCI-evoked alterations. We identified downstream mechanisms through which JAK/STAT3 pathway activation leads to the spreading of neuroinflammation. Our findings reveal that JAK/STAT3 signaling plays a major role in spinal cord plasticity and mechanical allodynia associated with peripheral nerve injury.
Nerve Growth Factor-Regulated Emergence of Functional δ-Opioid Receptors
Authors: Bie Bihua , Zhang Zhi , Cai You-Qing , Zhu Wei , Zhang Yong , Dai Jaile , Lowenstein Charles J. , Weinman Edward J. , Pan Zhizhong Z.
Published: April 2010

Sorting of intracellular G-protein-coupled receptors (GPCRs) either to lysosomes for degradation or to plasma membrane for surface insertion and functional expression is a key process regulating signaling strength of GPCRs across the plasma membrane in adult mammalian cells. However, little is known about the molecular mechanisms governing the dynamic process of receptor sorting to the plasma membrane for functional expression under normal and pathological conditions. In this study, we demonstrate that δ-opioid receptor (DOPr), a GPCR constitutively targeted to intracellular compartments, is driven to the surface membrane of central synaptic terminals and becomes functional by the neurotrophin nerve growth factor (NGF) in native brainstem neurons. The NGF-triggered DOPr translocation is predominantly mediated by the signaling pathway involving the tyrosine receptor kinase A, Ca2+-mobilizing phospholipase C, and Ca2+/calmodulin-dependent protein kinase II. Importantly, it requires interactions with the cytoplasmic sorting protein NHERF-1 (Na+/H+exchange regulatory factor-1) andN-ethyl-maleimide-sensitive factor-regulated exocytosis. In addition, this NGF-mediated mechanism is likely responsible for the emergence of functional DOPr induced by chronic opioids. Thus, NGF may function as a key molecular switch that redirects the sorting of intracellularly targeted DOPr to plasma membrane, resulting in new functional DOPr on central synapses under chronic opioid conditions.
Protein Kinase G Dynamically Modulates TASK1-Mediated Leak K+Currents in Cholinergic Neurons of the Basal Forebrain
Authors: Toyoda Hiroki , Saito Mitsuru , Okazawa Makoto , Hirao Keiko , Sato Hajime , Abe Haruka , Takada Kenji , Funabiki Kazuo , Takada Masahiko , Kaneko Takeshi , Kang Youngnam
Published: April 2010

Leak K+conductance generated by TASK1/3 channels is crucial for neuronal excitability. However, endogenous modulators activating TASK channels in neurons remained unknown. We previously reported that in the presumed cholinergic neurons of the basal forebrain (BF), activation of NO-cGMP-PKG (protein kinase G) pathway enhanced the TASK1-like leak K+current (I-Kleak). As 8-Br-cGMP enhanced theI-Kleakmainly at pH 7.3 as if changing theI-Kleakfrom TASK1-like to TASK3-like current, such an enhancement of theI-Kleakwould result either from an enhancement of hidden TASK3 component or from an acidic shift in the pH sensitivity profile of TASK1 component. In view of the report that protonation of TASK channel decreases its open probability, the present study was designed to examine whether the activation of PKG increases the conductance of TASK1 channels by reducing their binding affinity for H+, i.e., by increasingKdfor protonation, or not. We here demonstrate that PKG activation and inhibition respectively upregulate and downregulate TASK1 channels heterologously expressed in PKG-loaded HEK293 cells at physiological pH, by causing shifts in theKdin the acidic and basic directions, respectively. Such PKG modulations of TASK1 channels were largely abolished by mutating pH sensor H98. In the BF neurons that were identified to express ChAT and TASK1 channels, similar dynamic modulations of TASK1-like pH sensitivity ofI-Kleakwere caused by PKG. It is strongly suggested that PKG activation and inhibition dynamically modulate TASK1 currents at physiological pH by bidirectionally changingKdvalues for protonation of the extracellular pH sensors of TASK1 channels in cholinergic BF neurons.
Separating Value from Choice: Delay Discounting Activity in the Lateral Intraparietal Area
Authors: Louie Kenway , Glimcher Paul W.
Published: April 2010

The mathematical formulations used to study the neurophysiological signals governing choice behavior fall under one of two major theoretical frameworks: “choice probability” or “subjective value.” These two formulations represent behavioral quantities closely tied to the decision process, but it is unknown whether one of these variables, or both, dominates the neural mechanisms that mediate choice. Value and choice probability are difficult to distinguish in practice, because higher-valued options are chosen more frequently in free-choice tasks. This distinction is particularly relevant for sensorimotor areas such as parietal cortex, where both value information and motor signals related to choice have been observed. We recorded the activity of neurons in the lateral intraparietal area while monkeys performed an intertemporal choice task for rewards differing in delay to reinforcement. Here we show that the activity of parietal neurons is precisely correlated with the individual-specific discounted value of delayed rewards, with peak subjective value modulation occurring early in task trials. In contrast, late in the decision process these same neurons transition to encode the selected action. When directly compared, the strong delay-related modulation early during decision making is driven by subjective value rather than the monkey's probability of choice. These findings show that in addition to information about gains, parietal cortex also incorporates information about delay into a precise physiological correlate of economic value functions, independent of the probability of choice.
Metabolic Vulnerability Disposes Retinal Ganglion Cell Axons to Dysfunction in a Model of Glaucomatous Degeneration
Authors: Baltan Selva , Inman Denise M. , Danilov Camelia A. , Morrison Richard S. , Calkins David J. , Horner Philip J.
Published: April 2010

We tested the hypothesis that glaucoma disrupts electrophysiological conduction properties and axon function in optic nerve as a function of intraocular pressure (IOP) levels and age in the DBA/2J mouse model of glaucoma. The amplitude and the integral of electrical signals evoked along the axons decreased considerably by 6 months of age as a function of increasing IOP levels. At young ages, raised IOP was directly associated with increased vulnerability to metabolic challenge. Changes in the physiological function of the optic nerves were accentuated with aging, leading to loss of compound action potential in an entire population of fibers: small, slow conducting axons. This loss was accompanied with loss of small fiber axon counts and declining metabolic reserve by demonstrating IOP-dependent ATP decrease in mouse optic nerves. These data shed light on a novel potential mechanism of glaucoma pathology whereby increased IOP and declining metabolic capacity lead to axon liability and eventually dysfunction and loss.
Striatal Dopamine Modulates Basal Ganglia Output and Regulates Social Context-Dependent Behavioral Variability through D1Receptors
Authors: Leblois Arthur , Wendel Benjamin J. , Perkel David J.
Published: April 2010

Cortico-basal ganglia (BG) circuits are thought to promote the acquisition of motor skills through reinforcement learning. In songbirds, a specialized portion of the BG is responsible for song learning and plasticity. This circuit generates song variability that underlies vocal experimentation in young birds and modulates song variability depending on the social context in adult birds. When male birds sing in the presence of a female, a social context associated with decreased BG-induced song variability, the extracellular dopamine (DA) level is increased in the avian BG nucleus Area X. These results suggest that DA could trigger song variability changes through its action in Area X. Consistent with this hypothesis, we report that DA delivered to Area X weakens the output signal of the avian cortico-BG circuit. Acting through D1receptors, DA reduced responses in Area X to song playback and to electrical stimulation of its afferent cortical nucleus HVC (used as a proper name). Specifically, DA reduced the response to direct excitatory input and decreased firing variability in Area X pallidal neurons, which provide the output to the thalamus. As a consequence, DA delivery in Area X also decreased responses to song playback in the cortical output nucleus of the BG loop, the lateral magnocellular nucleus of the anterior nidopallium. Further, interfering with D1receptor transmission in Area X abolished social context-related changes in song variability. In conclusion, we propose that DA acts on D1receptors in Area X to modulate the BG output signal and trigger changes in song variability.
GSK3β Regulates Myelin-Dependent Axon Outgrowth Inhibition through CRMP4
Authors: Alabed Yazan Z. , Pool Madeline , Ong Tone Stephan , Sutherland Calum , Fournier Alyson E.
Published: April 2010

Myelin-associated inhibitors (MAIs) contribute to failed regeneration in the CNS. The intracellular signaling pathways through which MAIs block axonal repair remain largely unknown. Here, we report that the kinase GSK3β is directly phosphorylated and inactivated by MAIs, consequently regulating protein–protein interactions that are critical for myelin-dependent inhibition. Inhibition of GSK3β mimics the neurite outgrowth inhibitory effect of myelin. The inhibitory effects of GSK3β inhibitors and myelin are not additive indicating that GSK3β is a major effector of MAIs. Consistent with this, overexpression of GSK3β attenuates myelin inhibition. MAI-dependent phosphorylation and inactivation of GSK3β regulate phosphorylation of CRMP4, a cytosolic regulator of myelin inhibition, and its ability to complex with RhoA. Introduction of a CRMP4 antagonist attenuates the neurite outgrowth inhibitory properties of GSK3β inhibitors. We describe the first example of GSK3β inactivation in response to inhibitory ligands and link the neurite outgrowth inhibitory effects of GSK3β inhibition directly to CRMP4. These findings raise the possibility that GSK3β inhibition will not effectively promote long-distance CNS regeneration following trauma such as spinal cord injury.
DrosophilaNeurexin IV Interacts with Roundabout and Is Required for Repulsive Midline Axon Guidance
Authors: Banerjee Swati , Blauth Kevin , Peters Kimberly , Rogers Stephen L. , Fanning Alan S. , Bhat Manzoor A.
Published: April 2010

Slit/Roundabout (Robo) signaling controls midline repulsive axon guidance. However, proteins that interact with Slit/Robo at the cell surface remain largely uncharacterized. Here, we report that theDrosophilatransmembrane septate junction-specific protein Neurexin IV (Nrx IV) functions in midline repulsive axon guidance. Nrx IV is expressed in the neurons of the developing ventral nerve cord, andnrx IVmutants show crossing and circling of ipsilateral axons and fused commissures. Interestingly, the axon guidance defects observed innrx IVmutants seem independent of its other binding partners, such as Contactin and Neuroglian and the midline glia protein Wrapper, which interacts intranswith Nrx IV.nrx IVmutants show diffuse Robo localization, and dose-dependent genetic interactions betweennrx IV/roboandnrx IV/slitindicate that they function in a common pathway.In vivobiochemical studies reveal that Nrx IV associates with Robo, Slit, and Syndecan, and interactions between Robo and Slit, or Nrx IV and Slit, are affected innrx IVandrobomutants, respectively. Coexpression of Nrx IV and Robo in mammalian cells confirms that these proteins retain the ability to interact in a heterologous system. Furthermore, we demonstrate that the extracellular region of Nrx IV is sufficient to rescue Robo localization and axon guidance phenotypes innrx IVmutants. Together, our studies establish that Nrx IV is essential for proper Robo localization and identify Nrx IV as a novel interacting partner of the Slit/Robo signaling pathway.
Anti-Semitism and the Ideology of the Mexican Revolution
Authors: Lomnitz Claudio
Published: April 2010

This essay traces the development of the ideology that cast Mexico's prerevolutionary technocratic elite, the so-called científicos, as the masterminds of the country's ruination. It shows that anti-científico discourse took the shape of anti-Semitic ideology, even though there were no Jews in the group. Anti-científico rhetoric was first created by applying anti-Semitic invective taken directly from the Dreyfus Affair. The implications for Mexico's revolutionary nationalism are explored in the conclusion.
1929: The New York Stock Market Crash
Authors: James Harold
Published: April 2010

Stock market panics involve major psychological elements, and fear appears in the form of a reference to past events that seem to have analogies. Not only was 1929 an example of this process, in that the participants thought in terms of previous crises, but 1929 has also become the standard against which subsequent events are judged.
How Did Fear Become a Scientific Object and What Kind of Object Is It?
Authors: Leys Ruth
Published: April 2010

This essay provides an analysis of the role of posed facial expressions and of the facial image in the development of the science of fear.
Role of the transcriptional factors FOXO1 and PPARG on gene expression of SLC2A4 in endometrial tissue from women with polycystic ovary syndrome
Authors: Kohan Karla , Carvajal Rodrigo , Gabler Fernando , Vantman David , Romero Carmen , Vega Margarita
Published: April 2010

Fifty to seventy percent of patients with polycystic ovary syndrome (PCOS) present hyperinsulinemia. On the other hand, reports indicate that forkhead box class O 1 (FOXO1) and peroxisome proliferator-activated receptor-γ (PPARG) are involved in the insulin signaling pathway, regulating the gene expression of SLC2A4 (GLUT4). The negative effect of FOXO1 over PPARG transcription disappears when FOXO1 is phosphorylated (p-FOXO1) and excluded from the nucleus, whereas PPARG can suppress gene expression of SLC2A4. Scarce knowledge is available in endometrium of women with PCOS and hyperinsulinemia (PCOSE h-Ins) about the role of these factors. We aimed to evaluate whether the endocrine and metabolic status of PCOS modify the levels of gene and protein expression of FOXO1, PPARG, and SLC2A4 in the endometria from hyperinsulinemic PCOS women compared with controls. In endometria from control (CE,n=7) or PCOSE h-Ins (n=7), we determined the subcellular location and protein levels of p-FOXO1Ser319 and FOXO1/FOXO4 by immunohistochemistry and western blot respectively; gene and/or protein levels of PPARG and SLC2A4 were evaluated by RT-PCR and/or western blot. Cytoplasm location for FOXO1 and p-FOXO1Ser319 was immunodetected in both groups of endometria, showing significantly higher staining in PCOSE h-Ins for these proteins (P<0.05). In PCOSE h-Ins, gene and protein levels of PPARG were significantly higher than in CE, whereasSLC2A4mRNA was decreased (P<0.05). In conclusion, the derepression of PPARG transcription by the high levels of p-FOXO1Ser319 could partially account for the lower levels of SLC2A4 found in PCOSE h-Ins, suggesting an alteration of the endometrial function in these patients.