bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of Thyroid Imaging Reporting and Data System in the Ultrasound Assessment of Thyroid Nodules According to Physician Experience
Authors: Ko Su Yeon , Kim Eun-Kyung , Moon Hee Jung , Yoon Jung Hyun , Kim Ha Yan , Kwak Jin Young
Published: August 2015

Objective

The aim of this study was to investigate and compare the diagnostic performances of the Thyroid Imaging Reporting and Data System (TIRADS) in differentiating benign and malignant thyroid nodules according to the level of physician experience.

Materials and Methods

From March to October 2013, 1102 patients with 1128 thyroid nodules who underwent initial ultrasound-guided fine needle aspiration were included in this study. Thyroid nodules were categorized according to TIRADS. Diagnostic performances of ultrasound were compared according to performer experience using the χ2 test or Fisher exact test.

Results

Of 1128 thyroid nodules, 281 were malignant, and 847 were benign. The risk of malignancy of each TIRADS category by the experienced and less experienced physicians were as follows: category 3 (0.9% vs 0%), category 4a (3.5% vs 1.3%), category 4b (7.3% vs 12.1%), category 4c (67.5% vs 44.9%), and category 5 (97.7% vs 76.5%). Sensitivity, specificity, accuracy, positive predictive value, and negative predictive value were 99.1%, 35.9%, 52.5%, 35.5%, and 99.1%, respectively, for experienced physicians and 100%, 20.9%, 37.6%, 35.2%, and 100%, respectively, for less experienced physicians. Specificity, accuracy, and positive predictive value were statistically higher for experienced physicians than those for less experienced physicians (P < 0.001, 0.001, and 0.004). There was a significant difference in areas under the curve between the 2 groups (P < 0.001).

Conclusions

In conclusion, the diagnostic performance of the stratification of malignancy risk according to TIRADS categories was comparable between the experienced and less experienced physician groups. The application of TIRADS is reproducible, and it was easy to predict the probability of thyroid malignancy in both the experienced and less experienced physician groups.
Cognitive and Functional Correlates of NPI-Q Scores and Symptom Clusters in Mildly Demented Alzheimer Patients
Authors: Travis Seidl Jennifer N. , Massman Paul J.
Published: August 2015

Previous research has demonstrated an association between the emotional and behavioral symptoms of dementia, known as neuropsychiatric symptoms, and cognitive and functional decline among patients with Alzheimer disease (AD). The present study aimed to identify associations between neuropsychiatric symptoms as measured by the Neuropsychiatric Inventory-Questionnaire (NPI-Q) and cognitive and functional performance. Participants were 256 AD patients enrolled in the Alzheimer’s Disease and Memory Disorders Center at Baylor College of Medicine. An exploratory factor analysis of the NPI-Q indicated a 2-factor structure consisting of Negative/Oppositional and Anxiety/Restlessness factors. Regression analyses revealed significant associations between greater total severity of neuropsychiatric symptoms and poorer performance on basic and Instrumental Activities of Daily Living. Greater severity of Anxiety/Restlessness symptoms was associated with poor performance on measures of visuospatial functioning and basic and instrumental activities of daily living. The Negative/Oppositional factor was not related to cognition or functioning. In summary, neuropsychiatric symptoms (particularly Anxiety/Restlessness symptoms) were related to cognition and everyday functioning. Proper assessment and treatment of these symptoms is essential for improving cognition and functioning in AD patients.
Formation of Chromosomal Domains in Interphase by Loop Extrusion
Authors: Fudenberg Geoffrey , Imakaev Maxim , Lu Carolyn , Goloborodko Anton , Abdennur Nezar , Mirny Leonid A.
Published: August 2015

Topologically Associating Domains (TADs) are fundamental structural and functional building blocks of human interphase chromosomes, yet mechanisms of TAD formation remain unknown. Here we propose that loop extrusion underlies TAD formation. In this process, cis-acting loop-extruding factors, likely cohesins, form progressively larger loops, but stall at TAD boundaries due to interactions with boundary proteins, including CTCF. Using polymer simulations, we show that this model can produce TADs as determined by our analyses of Hi-C data. Contrary to typical illustrations, each TAD consists of multiple dynamically formed loops, rather than a single static loop. Our model explains diverse experimental observations, including the preferential orientation of CTCF motifs, enrichments of architectural proteins at TAD boundaries, and boundary deletion experiments, and makes specific predictions for depletion of CTCF versus cohesin. The emerging picture is that TADs arise from actively forming, growing, and dissociating loops, presenting a framework for understanding interphase chromosomal organization.
An integrative model of leukocyte genomics and organ dysfunction in heart failure patients requiring mechanical circulatory support
Authors: Wisniewski Nicholas , Bondar Galyna , Rau Christoph , Chittoor Jay , Chang Eleanor , Esmaeili Azadeh , Deng Mario
Published: August 2015

Background

The implantation of mechanical circulatory support (MCS) devices in heart failure patients is associated with a systemic inflammatory response, potentially leading to death from multiple organ dysfunction syndrome. Previous studies point to the involvement of many mechanisms, but an integrative hypothesis does not yet exist. Using time-dependent whole-genome mRNA expression in circulating leukocytes, we constructed a systems-model to improve mechanistic understanding and prediction of adverse outcomes.

Methods

We sampled peripheral blood mononuclear cells from 22 consecutive patients undergoing MCS surgery, at 5 timepoints: day -1 preoperative, and days 1, 3, 5, and 8 postoperative. Phenotyping was performed using 12 clinical parameters, 2 organ dysfunction scoring systems, and survival outcomes. We constructed a systems-representation using weighted gene co-expression network analysis, and annotated eigengenes using gene ontology, pathway, and transcription factor binding site enrichment analyses. Genes and eigengenes were mapped to the clinical phenotype using a linear mixed-effect model, with Cox models also fit at each timepoint to survival outcomes. Finally, we selected top genes associated with survival across all timepoints, and trained a penalized Cox model, based on day -1 data, to predict mortality risk thereafter.

Results

We inferred a 19-module network, in which most module eigengenes correlated with at least one aspect of the clinical phenotype. We observed a response to surgery orchestrated into stages: first, activation of the innate immune response, followed by anti-inflammation, and finally reparative processes such as mitosis, coagulation, and apoptosis. Eigengenes related to red blood cell production and extracellular matrix degradation became predictors of survival late in the timecourse, consistent with organ failure due to disseminated coagulopathy. Our final predictive model consisted of 10 genes:IL2RA,HSPA7, AFAP1, SYNJ2, LOC653406, GAPDHP35, MGC12916, ZRSR2, and two currently unidentified genes, warranting further investigation.

Conclusion

Our model provides an integrative representation of leukocyte biology during the systemic inflammatory response following MCS device implantation. It demonstrates consistency with previous hypotheses, identifying a number of known mechanisms. At the same time, it suggests novel hypotheses about time-specific targets.
Synergy of AMPA and NMDA receptor currents in dopaminergic neurons: a modeling study
Authors: Zakharov Denis , Christopher Lapis , Gutkin Boris , Kuznetsov Alexey
Published: August 2015

Dopaminergic (DA) neurons display two modes of firing: low-frequency tonic and high-frequency bursts. The high frequency firing within the bursts is attributed to NMDA, but not AMPA receptor activation. In our models of the DA neuron, both biophysical and abstract, the NMDA receptor current can significantly increase their firing frequency, whereas the AMPA receptor current is not able to evoke high-frequency activity and usually suppresses firing. However, both currents are produced by glutamate receptors and, consequently, are often co-activated. Here we consider combined influence of AMPA and NMDA synaptic input in the models of the DA neuron. Different types of neuronal activity (resting state, low frequency, or high frequency firing) are observed depending on the conductance of the AMPAR and NMDAR currents. In two models, biophysical and reduced, we show that the firing frequency increases more effectively if both receptors are co-activated for certain parameter values. In particular, in the more quantitative biophysical model, the maximal frequency is 40% greater than that with NMDAR alone. The dynamical mechanism of such frequency growth is explained in the framework of phase space evolution using the reduced model. In short, both the AMPAR and NMDAR currents flatten the voltage nullcline, providing the frequency increase, whereas only NMDA prevents complete unfolding of the nullcline, providing robust firing. Thus, we confirm a major role of the NMDAR in generating high-frequency firing and conclude that AMPAR activation further significantly increases the frequency.
Evidence of a role for radiation-induced lysosomal damage in non-targeted effects: an experimental and theoretical analysis
Authors: Bright Scott , Fletcher Alexander George , Fell David , Kadhim Munira A.
Published: August 2015

A well-known DNA-damaging agent and carcinogen, ionizing radiation (IR) can also exert detrimental effects in cells not directly exposed to it, through "non-targeted effects" (NTE). Whilst NTE are known to contribute to radiation-induced damage, their mechanism of induction and propagation remains incompletely understood. To investigate the possible role of lysosomes, key subcellular organelles, in NTE we used acridine orange uptake and relocation methods to monitor lysosomal permeability in irradiated and bystander human fibroblasts. As a potential mediator of lysosomal changes, oxidative stress was measured using the H2DCFDA assay for total reactive oxygen species (ROS). IR was found to induce significant lysosomal permeability in the first hour post irradiation, with reduced permeability persisting up to 24 hours. This occurred in conjunction with an increase in ROS in directly irradiated cells, in contrast with a decrease in ROS in bystander cells. Based on these observations we constructed a simple mathematical model of ROS-induced lysosomal damage, based on a bistable mechanism where a sufficiently strong IR insult can shift a cell from a 'low ROS, high lysosome' to a 'high ROS, low lysosome' state. This has profound cellular implications in radiation response and advances our understanding for the sub-cellular involvement in non-targeted effects.
Modeling the overproduction of ribosomes when antibacterial drugs act on cells
Authors: Maitra Arijit , Dill Ken A.
Published: August 2015

Bacteria that are subjected to ribosome inhibiting antibiotic drugs show an interesting behavior: Although the drug slows down cell growth, it also paradoxically increases the cell’s concentration of ribosomes. We combine a prior nonlinear model of the energy-biomass balance in undruggedE. colicells (Maitra and Dill, PNAS 2015) with Michaelis-Menten binding of drugs that inactivate ribosomes. Predictions are in good agreement with experiments on ribosomal concentrations and synthesis rates vs. drug concentrations and growth rates. The model indicates that added drug drives the cell to overproduce ribosomes keeping roughly constant the level of ribosomes producing ribosomal proteins, an important quantity for cell growth. The model also predicts that ribosomal production rates should increase, then decrease with added drug. This model gives insights into cellular driving forces and suggests new experiments.
Gene flow mediates the role of sex chromosome meiotic drive during complex speciation
Authors: Meiklejohn Colin D. , Landeen Emily L. , Gordon Kathleen E. , Rzatkiewicz Thomas , Kingan Sarah B. , Geneva Anthony J. , Vedanayagam Jeffrey P. , Muirhead Christina A. , Garrigan Daniel , Stern David L. , Presgraves Daven C.
Published: August 2015

During speciation, sex chromosomes often accumulate interspecific genetic incompatibilities faster than the rest of the genome. The drive theory posits that sex chromosomes are susceptible to recurrent bouts of meiotic drive and suppression, causing the evolutionary build-up of divergent cryptic sex-linked drive systems and, incidentally, genetic incompatibilities. To assess the role of drive during speciation, we combine high-resolution genetic mapping of X-linked hybrid male sterility with population genomics analyses of divergence and recent gene flow between the fruitfly species,Drosophila mauritianaandD. simulans. Our findings reveal a high density of genetic incompatibilities and a corresponding dearth of gene flow on the X chromosome. Surprisingly, we find that, rather than contributing to interspecific divergence, a known drive element has recently migrated between species, caused a strong reduction in local divergence, and undermined the evolution of hybrid sterility. Gene flow can therefore mediate the effects of selfish genetic elements during speciation.
GC skew defines distinct RNA polymerase pause sites in CpG island promoters
Authors: Kellner Wendy A. , Bell Joshua S.K. , Vertino Paula M.
Published: August 2015

CpG islands (CGIs) are associated with over half of human gene promoters and are characterized by a unique chromatin environment and high levels of bidirectional transcriptional activity relative to surrounding genomic regions, suggesting that RNA polymerase (Pol II) progression past the CGI boundaries is restricted. Here we describe a novel transcriptional regulatory step wherein Pol II encounters an additional barrier to elongation distinct from the promoter-proximal pause and occurring at the downstream boundary of the CGI domain. For most CGI-associated promoters, Pol II exhibits a dominant pause at either the promoter-proximal or this distal site that correlates, both in position and in intensity, with local regions of high GC skew, a sequence feature known to form unique secondary structures. Upon signal-induced gene activation, long-range enhancer contacts at the dominant pause site are selectively enhanced, suggesting a new role for enhancers at the downstream pause. These data point to an additional level of control over transcriptional output at a subset of CGI-associated genes that is linked to DNA sequence and the integrity of the CGI domain.
Conserved Functions of the MATE Transporter BIG EMBRYO1 in Regulation of Lateral Organ Size and Initiation Rate
Authors: Suzuki Masaharu , Sato Yutaka , Wu Shan , Kang Byung-Ho , McCarty Donald R.
Published: August 2015

Genetic networks that determine rates of organ initiation and organ size are key regulators of plant architecture. Whereas several genes that influence the timing of lateral organ initiation have been identified, the regulatory pathways in which these genes operate are poorly understood. Here, we identify a class of genes implicated in regulation of the lateral organ initiation rate. Loss-of-function mutations in the MATE transporter encoded by maize (Zea mays) Big embryo 1 (Bige1) cause accelerated leaf and root initiation as well as enlargement of the embryo scutellum. BIGE1 is localized to trans-Golgi, indicating a possible role in secretion of a signaling molecule. Interestingly, phenotypes of bige1 bear striking similarity to cyp78a mutants identified in diverse plant species. We show that a CYP78A gene is upregulated in bige1 mutant embryos, suggesting a role for BIGE1 in feedback regulation of a CYP78A pathway. We demonstrate that accelerated leaf formation and early flowering phenotypes conditioned by mutants of Arabidopsis thaliana  BIGE1 orthologs are complemented by maize Bige1, showing that the BIGE1 transporter has a conserved function in regulation of lateral organ initiation in plants. We propose that BIGE1 is required for transport of an intermediate or product associated with the CYP78A pathway.
The Transcriptional Coregulator LEUNIG_HOMOLOG Inhibits Light-Dependent Seed Germination in Arabidopsis
Authors: Lee Nayoung , Park Jeongmoo , Kim Keunhwa , Choi Giltsu
Published: August 2015

PHYTOCHROME-INTERACTING FACTOR1 (PIF1) is a basic helix-loop-helix transcription factor that inhibits light-dependent seed germination in Arabidopsis thaliana. However, it remains unclear whether PIF1 requires other factors to regulate its direct targets. Here, we demonstrate that LEUNIG_HOMOLOG (LUH), a Groucho family transcriptional corepressor, binds to PIF1 and coregulates its targets. Not only are the transcriptional profiles of the luh and pif1 mutants remarkably similar, more than 80% of the seeds of both genotypes germinate in the dark. We show by chromatin immunoprecipitation that LUH binds a subset of PIF1 targets in a partially PIF1-dependent manner. Unexpectedly, we found LUH binds and coregulates not only PIF1-activated targets but also PIF1-repressed targets. Together, our results indicate LUH functions with PIF1 as a transcriptional coregulator to inhibit seed germination.
Discourse analysis and the study of educational leadership
Authors: Anderson Gary , Mungal Angus Shiva
Published: August 2015

Purpose

– The purpose of this paper is to provide an overview of the current and past work using discourse analysis in the field of educational administration and of discourse analysis as a methodology.

Design/methodology/approach

– Authors reviewed research in educational leadership that uses discourse analysis as a methodology.

Findings

– While discourse analysis has been used in the field, little work has been done that explores “leadership” as a discourse practice.

Originality/value

– Increased use of discourse analysis in the field might unearth the ways principals and superintendents are creators of discourse and mediators of the discourses of others.
Interpreting Injury Mechanisms of Blunt Force Trauma from Butterfly Fracture Formation
Authors: Reber Samantha L. , Simmons Tal
Published: August 2015

According to biomechanics of fracture production during blunt impact, tubular bones are subject to compressive (impact site) and tensile (opposite impact site) forces; this causes bones to break in tension before compression, producing Y‐shaped fracture patterns with breakaway (butterfly) fragments. In current forensic models, the side of the bone exhibiting the breakaway fragment is designated the impact side, with initial breakage occurring opposite. Fracture production and patterning of blunt impacts to 255 sheep femora were analyzed. Contra the existing model, only 60% of complete butterfly fractures exhibited impact side breakaway fragments. Although fractures initiated on the tension, nonimpact side, butterfly fragments formed on either compression or tension sides. Using newly defined breakaway fragment shape criteria, impact side was estimated with 98% accuracy for both complete and partial butterfly fractures. Furthermore, the results suggest that the impact site is the located on one of the Y‐fracture's arms, not the butterfly fragment's center, as previously modeled.
Very serious and non‐ignorable problem: Crisis in emergency medical response in catastrophic event
Authors: Shen Weifeng , Jiang Libing , Zhang Mao , Ma Yuefeng , Jiang Guanyu , He Xiaojun
Published: August 2015

The crisis of medical response caused by catastrophic events might significantly affect emergency response, and might even initiate more serious social crisis. Therefore, early identification and timely blocking the formation of crisis in the early phase after a major disaster will improve the efficiency of medical response in a major disaster and avoid serious consequences. In the present paper, we described the emergency strategy to crisis management of medical response after a major disaster. Major catastrophic events often lead to various crises, including excess demand, the crisis of response in barrier and the structural crisis in response. The corresponding emergency response strategies include: (i) shunt of catastrophic medical surge; (ii) scalability of medical surge capacity; (iii) matching of the structural elements of response; (iv) maintaining the functions of support system for medical response and maximising the operation of the integrated response system; and (v) selection of appropriate care ‘standard’ in extreme situations of overload of disaster medical surge. In conclusion, under the impact of a major catastrophic event, medical response is often complex and the medical surge beyond the conventional response capacity and it is easy to be in crisis. In addition to the current consensus of disaster response, three additional aspects should be considered. First, all relevant society forces led by the government and military should be linkages. Second, a powerful medical response system must be based on a strong support system. Third, countermeasures of medical surge should be applied flexibly to the special and specific disaster environment, to promote the effective medical response force.
Diagnostics and Discovery in Viral Central Nervous System Infections
Authors: Lipkin Walter Ian , Hornig Mady
Published: August 2015

The range of viruses implicated in central nervous system disease continues to grow with globalization of travel and trade, emergence and reemergence of zoonoses and investments in discovery science. Diagnosis of viral central nervous system infections is challenging in that brain tissue, where the pathogen concentration is likely to be highest, is not readily obtained and sensitive methods for molecular and serological detection of infection are not available in most clinical microbiology laboratories. Here we review these challenges and discuss how they may be addressed using advances in molecular, proteomic and immunological methods.
Henipavirus Encephalitis: Recent Developments and Advances
Authors: Ong Kien Chai , Wong Kum Thong
Published: August 2015

The genusHenipaviruswithin the familyParamyxoviridae includes the Hendra virus (HeV) andNipah virus (NiV) which were discovered in the 1990s inAustralia andMalaysia, respectively, after emerging to cause severe and often fatal outbreaks in humans and animals. WhileHeVis confined toAustralia, more recentNiVoutbreaks have been reported inBangladesh,India and thePhilippines. The clinical manifestations of both henipaviruses in humans appear similar, with a predominance of an acute encephalitic syndrome. Likewise, the pathological features are similar and characterized by disseminated, multi‐organ vasculopathy comprising endothelial infection/ulceration, vasculitis, vasculitis‐induced thrombosis/occlusion, parenchymal ischemia/microinfarction, and parenchymal cell infection in the central nervous system (CNS), lung, kidney and other major organs. This unique dual pathogenetic mechanism of vasculitis‐induced microinfarction and neuronal infection causes severe tissue damage in theCNS. Both viruses can also cause relapsing encephalitis months and years after the acute infection. Many animal models studied to date have largely confirmed the pathology of henipavirus infection, and provided the means to test new therapeutic agents and vaccines. As the bat is the natural host of henipaviruses and has worldwide distribution, spillover events into human populations are expected to occur in the future.
Understanding Enterovirus 71 Neuropathogenesis and Its Impact on Other Neurotropic Enteroviruses
Authors: Ong Kien Chai , Wong Kum Thong
Published: August 2015

Enterovirus A71 (EV‐A71) belongs to the species group A in the Enterovirus genus within the Picornaviridae family. EV‐A71 usually causes self‐limiting hand, foot and mouth disease or herpangina but rarely causes severe neurological complications such as acute flaccid paralysis and encephalomyelitis. The pathology and neuropathogenesis of these neurological syndromes is beginning to be understood. EV‐A71 neurotropism for motor neurons in the spinal cord and brainstem, and other neurons, is mainly responsible for central nervous system damage. This review on the general aspects, recent developments and advances of EV‐A71 infection will focus on neuropathogenesis and its implications on other neurotropic enteroviruses, such as poliovirus and the newly emergent Enterovirus D68. With the imminent eradication of poliovirus, EV‐A71 is likely to replace it as an important neurotropic enterovirus of worldwide importance.
West Nile Virus Encephalitis 16 Years Later
Authors: Kleinschmidt‐DeMasters Bette K. , Beckham J. David
Published: August 2015

Arboviruses (Arthropod‐borne viruses) include several families of viruses (Flaviviridae, Togaviradae, Bunyaviradae, Reoviradae) that are spread by arthropod vectors, most commonly mosquitoes, ticks and sandflies. The RNA genome allows these viruses to rapidly adapt to ever‐changing host and environmental conditions. Thus, these virus families are largely responsible for the recent expansion in geographic range of emerging viruses including West Nile virus (WNV), dengue virus and Chikungunya virus. This review will focus on WNV, especially as it has progressively spread westward in North America since its introduction in New York in 1999. By 2003, WNV infections in humans had reached almost all lower 48 contiguous United States (US) and since that time, fluctuations in outbreaks have occurred. Cases decreased between 2008 and 2011, followed by a dramatic flair in 2012, with the epicenter in the Dallas‐Fort Worth region of Texas. The 2012 outbreak was associated with an increase in reported neuroinvasive cases. Neuroinvasive disease continues to be a problem particularly in the elderly and immunocompromised populations, although WNV infections also represented the second most frequent cause of pediatric encephalitis in these same years. Neuropathological features in cases from the 2012 epidemic highlight the extent of viral damage that can occur in the CNS.
Emerging Infections of CNS: Avian Influenza A Virus, Rift Valley Fever Virus and Human Parechovirus
Authors: Wiley Clayton A. , Bhardwaj Nitin , Ross Ted M. , Bissel Stephanie J.
Published: August 2015

History is replete with emergent pandemic infections that have decimated the human population. Given the shear mass of humans that now crowd the earth, there is every reason to suspect history will repeat itself. We describe three RNA viruses that have recently emerged in the human population to mediate severe neurological disease. These new diseases are results of new mutations in the infectious agents or new exposure pathways to the agents or both. To appreciate their pathogenesis, we summarize the essential virology and immune response to each agent. Infection is described in the context of known host defenses. Once the viruses evade immune defenses and enter central nervous system (CNS) cells, they rapidly co‐opt host RNA processing to a cataclysmic extent. It is not clear why the brain is particularly susceptible to RNA viruses; but perhaps because of its tremendous dependence on RNA processing for physiological functioning, classical mechanisms of host defense (eg, interferon disruption of viral replication) are diminished or not available. Effectiveness of immunity, immunization and pharmacological therapies is reviewed to contextualize the scope of the public health challenge. Unfortunately, vaccines that confer protection from systemic disease do not necessarily confer protection for the brain after exposure through unconventional routes.
Actions of KMUP‐1, a xanthine and piperazine derivative, on voltage‐gated Na+ and Ca2+‐activated K+ currents in GH3 pituitary tumour cells
Authors: Lo Yi‐Ching , Tseng Yu‐Ting , Liu Chi‐Ming , Wu Bin‐Nan , Wu Sheng‐Nan
Published: August 2015

Background and Purpose

7‐[2‐[4‐(2‐Chlorophenyl)piperazinyl]ethyl]‐1,3‐dimethylxanthine (KMUP‐1) is a xanthine‐based derivative. It has soluble GC activation and K+‐channel opening activity. Effects of this compound on ion currents in pituitary GH3 cells were investigated in this study.

Experimental Approach

The aim of this study was to evaluate effects of KMUP‐1 on the amplitude and gating of voltage‐gated Na+ current (INa) in pituitary GH3 cells and in HEKT293T cells expressing SCN5A. Both the amplitude of Ca2+‐activated K+ current and the activity of large‐conductance Ca2+‐activated K+ (BKCa) channels were also studied.

Key Results

KMUP‐1 depressed the transient and late components of INa with different potencies. The IC50 values required for its inhibitory effect on transient and late INa were 22.5 and 1.8 μM respectively. KMUP‐1 (3 μM) shifted the steady‐state inactivation of INa to a hyperpolarized potential by −10 mV, despite inability to alter the recovery of INa from inactivation. In cell‐attached configuration, KMUP‐1 applied to bath increased BKCa‐channel activity; however, in inside‐out patches, this compound applied to the intracellular surface had no effect on it. It prolonged the latency in the generation of action currents elicited by triangular voltage ramps. Additionally, KMUP‐1 decreased the peak INa with a concomitant increase of current inactivation in HEKT293T cells expressing SCN5A.

Conclusions and Implications

Apart from activating BKCa channels, KMUP‐1 preferentially suppresses late INa. The effects of KUMP‐1 on ion currents presented here constitute an underlying ionic mechanism of its actions.
Pro‐cognitive activity in rats of 3‐furan‐2‐yl‐N‐p‐tolyl‐acrylamide, a positive allosteric modulator of the α7 nicotinic acetylcholine receptor
Authors: Potasiewicz A. , Kos T. , Ravazzini F. , Puia G. , Arias H. R. , Popik P , Nikiforuk A.
Published: August 2015

Background and Purpose

α7 nicotinic acetylcholine receptors (α7 nAChRs) may represent useful targets for cognitive improvement. The aim of this study is to compare the pro‐cognitive activity of selective α7‐nAChR ligands, including the partial agonists, DMXBA and A‐582941, as well as the positive allosteric modulator, 3‐furan‐2‐yl‐N‐p‐tolyl‐acrylamide (PAM‐2).

Experimental Approach

The attentional set‐shifting task (ASST) and the novel object recognition task (NORT) in rats, were used to evaluate the pro‐cognitive activity of each ligand [i.e., PAM‐2 (0.5, 1.0, and 2.0 mg·kg−1), DMXBA and A‐582941 (0.3 and 1.0 mg·kg−1)], in the absence and presence of methyllycaconitine (MLA), a selective competitive antagonist. To determine potential drug interactions, an inactive dose of PAM‐2 (0.5 mg·kg−1) was co‐injected with inactive doses of either agonist ‐ DMXBA: 0.1 (NORT); 0.3 mg·kg−1 (ASST) or A‐582941: 0.1 mg·kg−1.

Key Results

PAM‐2, DMXBA, and A‐582941 improved cognition in a MLA‐dependent manner, indicating that the observed activities are mediated by α7 nAChRs. Interestingly, the co‐injection of inactive doses of PAM‐2 and DMXBA or A‐582941 also improved cognition, suggesting drug interactions. Moreover, PAM‐2 reversed the scopolamine‐induced NORT deficit. The electrophysiological results also support the view that PAM‐2 potentiates the α7 nAChR currents elicited by a fixed concentration (3 μM) of DMXBA with apparent EC50 = 34 ± 3 μM and Emax = 225 ± 5 %.

Conclusions and Implications

Our results support the view that α7 nAChRs are involved in cognition processes and that PAM‐2 is a novel promising candidate for the treatment of cognitive disorders.
Superagonism at G protein‐coupled receptors and beyond
Authors: Schrage R , De Min A , Hochheiser K , Kostenis E , Mohr K
Published: August 2015

Ligands targeting GPCRs can be categorized according to their intrinsic efficacy to trigger a specific, receptor‐mediated response. A ligand endowed with the same level of efficacy as the endogenous agonist can be classified as a full agonist, whereas a compound that displays greater efficacy, that is, higher receptor signalling output than the endogenous agonist, can be called a superagonist. Subsequent to GPCR activation, an intracellular signalling cascade is set in motion, which may generate substantial amplification of the signal. This may obscure superagonism in pharmacological assays and, therefore, the definition of superagonism necessitates a combination of operational approaches, reduction of spare receptors or estimation of receptor activation close to the receptor level to quantify relative agonist efficacies in a particular system.

The first part of this review will compare GPCR superagonism with superagonism in the field of immunology, where this term is well established. In the second part, known GPCR superagonists will be reviewed. Then, the experimental and analytical challenges in the deconvolution of GPCR superagonism will be addressed. Finally, the potential benefit of superagonism is discussed.

The molecular mechanisms behind GPCR superagonism are not completely understood. However, crystallography shows that agonist binding alone is not sufficient for a fully active receptor state and that binding of the G protein is at least equally important. Accordingly, the emerging number of reported superagonists implies that ligand‐induced receptor conformations more active than the ones stabilized by the endogenous agonist are indeed feasible. Superagonists may have therapeutic potential when receptor function is impaired or to induce negative feedback mechanisms.

Linked Articles

This article is part of a themed section on Molecular Pharmacology of G Protein‐Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc
High glucose‐induced changes in hyaloid‐retinal vessels during early ocular development of zebrafish: a short‐term animal model of diabetic retinopathy
Authors: Jung Seung‐Hyun , Kim Young Sook , Lee Yu‐Ri , Kim Jin Sook
Published: August 2015

Background and Purpose

Although a variety of animal models have been used to test drug candidates and examine the pathogenesis of diabetic retinopathy, time‐saving and inexpensive models are still needed to evaluate the increasing number of therapeutic approaches.

Experimental Approach

We developed a model for diabetic retinopathy using the early stage of transgenic zebrafish (flk:EGFP) by treating embryos with 130 mM glucose, from 3‐6 days post fertilisation (high‐glucose model). On day 6, lenses from zebrafish larvae were isolated and treated with 3% trypsin, and changes in hyaloid‐retinal vessels were analysed using fluorescent stereomicroscopy. In addition, expression of tight junction proteins (such as zonula occludens‐1), effects of hyperosmolar solutions and of hypoxia, andVegfexpression were assessed by RT –PCR. NO production was assessed with a fluorescent substrate. Effects of inhibitors of the VEGF receptor, NO synthesis and a VEGF antibody (ranibizumab) were also measured.

Key Results

In this high‐glucose model, dilation of hyaloid‐retinal vessels, on day 6, was accompanied by morphological lesions with disruption of tight junction proteins, overproduction ofVegfmRNA and increased NO production. Treatment of this high‐glucose model with an inhibitor of VEGF receptor tyrosine kinase or an inhibitor of NO synthase or ranibizumab decreased dilation of hyaloid‐retinal vessels.

Conclusions and Implications

These findings suggest that short‐term exposure of zebrafish larvae to high‐glucose conditions could be used for screening and drug discovery for diabetic retinopathy and particularly for disorders of retinal vessels related to disruption of tight junction proteins and excessive VEGF and NO production.
Neurokinin 1 receptor blockade in the medial amygdala attenuates alcohol drinking in rats with innate anxiety but not in Wistar rats
Authors: Ayanwuyi Lydia O , Stopponi Serena , Ubaldi Massimo , Cippitelli Andrea , Nasuti Cinzia , Damadzic Ruslan , Heilig Markus , Schank Jesse , Cheng Kejun , Rice Kenner C , Ciccocioppo Roberto
Published: August 2015

Background and Purpose

Substance P and its preferred neurokinin receptor NK1 have been implicated in stress and anxiety and have been proposed as possible therapeutic targets for the treatment of anxiety/depression. Attention is also being focused on the role this neuropeptide system may play in drug addiction, because stress‐related mechanisms promote drug abuse.

Experimental Approach

The effects of the rat‐specific NK1 receptor antagonist, L822429, on alcohol intake and seeking behaviour was investigated in genetically selected Marchigian Sardinian alcohol preferring rats. These rats demonstrate an anxious phenotype and are highly sensitive to stress and stress‐induced drinking.

Key Results

Systemic administration of L822429 significantly reduced operant alcohol self‐administration in Marchigian Sardinian alcohol preferring rats, but did not reduce alcohol self‐administration in stock Wistar rats. NK1 receptor antagonism also attenuated yohimbine‐induced reinstatement of alcohol seeking at all doses tested but had no effect on cue‐induced reinstatement of alcohol seeking. L822429 reduced operant alcohol self‐administration when injected into the lateral cerebroventricles or the medial amygdala. L822429 injected into the medial amygdala also significantly reduced anxiety‐like behaviour in the elevated plus maze test. No effects on alcohol intake were observed following injection of L822429 into the dorsal or the ventral hippocampus.

Conclusions and Implications

Our results suggest that NK1 receptor antagonists may be useful for the treatment of alcohol addiction associated with stress or comorbid anxiety disorders. The medial amygdala appears to be an important brain site of action of NK1 receptor antagonism.
Metabotropic glutamate receptor subtype 5: molecular pharmacology, allosteric modulation and stimulus bias
Authors: Sengmany K , Gregory K J
Published: August 2015

The metabotropic glutamate receptor subtype 5 (mGlu5) is a family C GPCR that has been implicated in various neuronal processes and, consequently, in several CNS disorders. Over the past few decades, GPCR‐based drug discovery, including that for mGlu5 receptors, has turned considerable attention to targeting allosteric binding sites. Modulation of endogenous agonists by allosteric ligands offers the advantages of spatial and temporal fine‐tuning of receptor activity, increased selectivity and reduced adverse effects with the potential to elicit improved clinical outcomes. Further, with greater appreciation of the multifaceted nature of the transduction of mGlu5 receptor signalling, it is increasingly apparent that drug discovery must take into consideration unique receptor conformations and the potential for stimulus‐bias. This novel paradigm proposes that different ligands may differentially modulate distinct signalling pathways arising from the same receptor. We review our current understanding of the complexities of mGlu5 receptor signalling and regulation, and how these relate to allosteric ligands. Ultimately, a deeper appreciation of these relationships will provide the foundation for targeted drug design of compounds with increased selectivity, not only for the desired receptor but also for the desired signalling outcome from the receptor.

Linked Articles

This article is part of a themed section on Molecular Pharmacology of G Protein‐Coupled Receptors. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v173.20/issuetoc
Human induced pluripotent stem cell‐derived versus adult cardiomyocytes: an in silico electrophysiological study on effects of ionic current block
Authors: Paci M , Hyttinen J , Rodriguez B , Severi S
Published: August 2015

Background and Purpose

Two new technologies are likely to revolutionize cardiac safety and drug development: in vitro experiments on human‐induced pluripotent stem cell‐derived cardiomyocytes (hiPSC‐CMs) and in silico human adult ventricular cardiomyocyte (hAdultV‐CM) models. Their combination was recently proposed as a potential replacement for the present hERG‐based QT study for pharmacological safety assessments. Here, we systematically compared in silico the effects of selective ionic current block on hiPSC‐CM and hAdultV‐CM action potentials (APs), to identify similarities/differences and to illustrate the potential of computational models as supportive tools for evaluating new in vitro technologies.

Experimental Approach

In silico AP models of ventricular‐like and atrial‐like hiPSC‐CMs and hAdultV‐CM were used to simulate the main effects of four degrees of block of the main cardiac transmembrane currents.

Key Results

Qualitatively, hiPSC‐CM and hAdultV‐CM APs showed similar responses to current block, consistent with results from experiments. However, quantitatively, hiPSC‐CMs were more sensitive to block of (i) L‐type Ca2+ currents due to the overexpression of the Na+/Ca2+ exchanger (leading to shorter APs) and (ii) the inward rectifier K+ current due to reduced repolarization reserve (inducing diastolic potential depolarization and repolarization failure).

Conclusions and Implications

In silico hiPSC‐CMs and hAdultV‐CMs exhibit a similar response to selective current blocks. However, overall hiPSC‐CMs show greater sensitivity to block, which may facilitate in vitro identification of drug‐induced effects. Extrapolation of drug effects from hiPSC‐CM to hAdultV‐CM and pro‐arrhythmic risk assessment can be facilitated by in silico predictions using biophysically‐based computational models.
State‐dependent blocking mechanism of Kv1.3 channels by the antimycobacterial drug clofazimine
Authors: Faouzi Malika , Starkus John , Penner Reinhold
Published: August 2015

Background and Purpose

Kv1.3 potassium channels are promising pharmaceutical targets for treating immune diseases as they modulate Ca2+ signalling in T cells by regulating the membrane potential and with it the driving force for Ca2+ influx. The antimycobacterial drug clofazimine has been demonstrated to attenuate antigen‐induced Ca2+ oscillations, suppress cytokine release and prevent skin graft rejection by inhibiting Kv1.3 channels with high potency and selectivity.

Experimental Approach

We used patch‐clamp methodology to investigate clofazimine's mechanism of action in Kv1.3 channels expressed in HEK293 cells.

Key Results

Clofazimine blocked Kv1.3 channels by involving two discrete mechanisms, both of which contribute to effective suppression of channels: (i) a use‐dependent open‐channel block during long depolarizations, resulting in accelerated K+ current inactivation and (ii) a block of closed deactivated channels after channels were opened by brief depolarizations. Both modes of block were use‐dependent and state‐dependent in that they clearly required prior channel opening. The clofazimine‐sensitive closed‐deactivated state of the channel was distinct from the resting closed state because channels at hyperpolarized voltages were not inhibited by clofazimine. Neither were channels in the C‐type inactivated state significantly affected. Kv1.3 channels carrying the H399T mutation and lacking C‐type inactivation were insensitive to clofazimine block of the closed‐deactivated state, but retained their susceptibility to open‐channel block.

Conclusions and Implications

Given the prominent role of Kv1.3 in shaping Ca2+ oscillations, the use‐dependent and state‐dependent block of Kv1.3 channels by clofazimine offers therapeutic potential for selective immunosuppression in the context of autoimmune diseases in which Kv1.3‐expressing T cells play a significant role.
Priming and memory of stress responses in organisms lacking a nervous system
Authors: Hilker Monika , Schwachtje Jens , Baier Margarete , Balazadeh Salma , Bäurle Isabel , Geiselhardt Sven , Hincha Dirk K. , Kunze Reinhard , Mueller‐Roeber Bernd , Rillig Matthias C. , Rolff Jens , Romeis Tina , Schmülling Thomas , Steppuhn Anke , van Dongen Joost , Whitcomb Sarah J. , Wurst Susanne , Zuther Ellen , Kopka Joachim
Published: August 2015

Experience and memory of environmental stimuli that indicate future stress can prepare (prime) organismic stress responses even in species lacking a nervous system. The process through which such organisms prepare their phenotype for an improved response to future stress has been termed ‘priming’. However, other terms are also used for this phenomenon, especially when considering priming in different types of organisms and when referring to different stressors. Here we propose a conceptual framework for priming of stress responses in bacteria, fungi and plants which allows comparison of priming with other terms, e.g. adaptation, acclimation, induction, acquired resistance and cross protection. We address spatial and temporal aspects of priming and highlight current knowledge about the mechanisms necessary for information storage which range from epigenetic marks to the accumulation of (dormant) signalling molecules. Furthermore, we outline possible patterns of primed stress responses. Finally, we link the ability of organisms to become primed for stress responses (their ‘primability’) with evolutionary ecology aspects and discuss which properties of an organism and its environment may favour the evolution of priming of stress responses.
Significant role of Psf3 expression in non‐small‐cell lung cancer
Authors: Tane Shinya , Sakai Yasuhiro , Hokka Daisuke , Okuma Hiromichi , Ogawa Hiroyuki , Tanaka Yugo , Uchino Kazuya , Nishio Wataru , Yoshimura Masahiro , Maniwa Yoshimasa
Published: August 2015

The GINS complex associates with cell division cycle (Cdc) protein 45 and mini‐chromosome maintenance (Mcm) proteins 2–7 to form the Cdc45–Mcm–GINS (CMG) complex, which is essential for DNA duplication. One member of the GINS complex is Psf3. We previously found that increased Psf3 expression was strongly associated with poor survival in lung adenocarcinoma. Here, we investigated the role of Psf3 expression in non‐small‐cell lung cancer (NSCLC). We verified Psf3 expression in human NSCLC tissues (180 patients) and cell lines. Immunohistochemical analysis revealed that the overexpression of Psf3 was significantly associated with vessel invasion (P = 0.016), lymphatic invasion (P = 0.002), and pleural invasion (P = 0.036). The overall survival rate in patients with Psf3 overexpression was significantly lower than that in patients without Psf3 overexpression (P = 0.006). Multivariate survival analysis revealed Psf3 expression to be an independent risk factor for an unfavorable outcome (P = 0.049). A proximal ligation assay showed interactions between Psf3 and other CMG components (such as Mcm2 and Cdc45) in both NSCLC specimens and cell lines, indicating that Psf3 acted as the CMG complex, which could lead to excessive proliferation. Knockdown of Psf3 inhibited the proliferation of both cell lines by delaying the S phase, which revealed that Psf3 played an important role in cancer proliferation. Thus, Psf3 acted as the CMG complex, promoting excessive proliferation. These results suggest that Psf3 inhibition might be a therapeutic target for NSCLC with Psf3 overexpression.