bluuebunny/crossref_metadata_2025_split huggingface dataset:
Functional abnormalities in iPSC‐derived cardiomyocytes generated from CPVT1 and CPVT2 patients carrying ryanodine or calsequestrin mutations
Authors: Novak Atara , Barad Lili , Lorber Avraham , Gherghiceanu Mihaela , Reiter Irina , Eisen Binyamin , Eldor Liron , Itskovitz‐Eldor Joseph , Eldar Michael , Arad Michael , Binah Ofer 
Published: July 2015

AbstractCatecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmia characterized by syncope and sudden death occurring during exercise or acute emotion. CPVT is caused by abnormal intracellular Ca2+ handling resulting from mutations in the RyR2 or CASQ2 genes. Because CASQ2 and RyR2 are involved in different aspects of the excitation‐contraction coupling process, we hypothesized that these mutations are associated with different functional and intracellular Ca²+ abnormalities. To test the hypothesis we generated induced Pluripotent Stem Cell‐derived cardiomyocytes (iPSC‐CM) from CPVT1 and CPVT2 patients carrying the RyR2R420Q and CASQ2D307H mutations, respectively, and investigated in CPVT1 and CPVT2 iPSC‐CM (compared to control): (i) The ultrastructural features; (ii) the effects of isoproterenol, caffeine and ryanodine on the [Ca2+]i transient characteristics. Our major findings were: (i) Ultrastructurally, CASQ2 and RyR2 mutated cardiomyocytes were less developed than control cardiomyocytes. (ii) While in control iPSC‐CM isoproterenol caused positive inotropic and lusitropic effects, in the mutated cardiomyocytes isoproterenol was either ineffective, caused arrhythmias, or markedly increased diastolic [Ca2+]i. Importantly, positive inotropic and lusitropic effects were not induced in mutated cardiomyocytes. (iii) The effects of caffeine and ryanodine in mutated cardiomyocytes differed from control cardiomyocytes. Our results show that iPSC‐CM are useful for investigating the similarities/differences in the pathophysiological consequences of RyR2 versus CASQ2 mutations underlying CPVT1 and CPVT2 syndromes.
A novel TXNIP‐based mechanism for Cx43‐mediated regulation of oxidative drug injury
Authors: Gao Kun , Chi Yuan , Zhang Xiling , Zhang Hui , Li Gang , Sun Wei , Takeda Masayuki , Yao Jian 
Published: July 2015

AbstractGap junctions (GJs) play an important role in the regulation of cell response to many drugs. However, little is known about their mechanisms. Using an in vitro model of cytotoxicity induced by geneticin (G418), we explored the potential signalling mechanisms involved. Incubation of cells with G418 resulted in cell death, as indicated by the change in cell morphology, loss of cell viability and activation of caspase‐3. Before the onset of cell injury, G418 induced reactive oxygen species (ROS) generation, activated oxidative sensitive kinase P38 and caused a shift of connexin 43 (Cx43) from non‐phosphorylated form to hyperphosphorylated form. These changes were largely prevented by antioxidants, suggesting an implication of oxidative stress. Downregulation of Cx43 with inhibitors or siRNA suppressed the expression of thioredoxin‐interacting protein (TXNIP), activated Akt and protected cells against the toxicity of G418. Further analysis revealed that inhibition of TXNIP with siRNA activated Akt and reproduced the protective effect of Cx43‐inhibiting agents, whereas suppression of Akt sensitized cells to the toxicity of G418. Furthermore, interference of TXNIP/Akt also affected puromycin‐ and adriamycin‐induced cell injury. Our study thus characterized TXNIP as a presently unrecognized molecule implicated in the regulatory actions of Cx43 on oxidative drug injury. Targeting Cx43/TXNIP/Akt signalling cascade might be a promising approach to modulate cell response to drugs.
Ginsenoside Rg1 improves bone marrow haematopoietic activity via extramedullary haematopoiesis of the spleen
Authors: Liu Hua‐Hsing , Chen Fei‐Peng , Liu Rong‐Kai , Lin Chun‐Lin , Chang Ko‐Tung 
Published: July 2015

AbstractCyclophosphamide (CY) is a chemotherapeutic agent used for cancer and immunological diseases. It induces cytotoxicity of bone marrow and causes myelosuppression and extramedullary haematopoiesis (EMH) in treated patients. EMH is characterized with the emergence of multipotent haematopoietic progenitors most likely in the spleen and liver. Previous studies indicated that a Chinese medicine, ginsenoside Rg1, confers a significant effect to elevate the number of lineage (Lin−) Sca‐1+ c‐Kit+ haematopoietic stem and progenitor cells (HSPCs) and restore the function of bone marrow in CY‐treated myelosuppressed mice. However, whether the amelioration of bone marrow by Rg1 accompanies an alleviation of EMH in the spleen was still unknown. In our study, the cellularity and weight of the spleen were significantly reduced after Rg1 treatment in CY‐treated mice. Moreover, the number of c‐Kit+ HSPCs was significantly decreased but not as a result of apoptosis, indicating that Rg1 alleviated EMH of the spleen induced by CY. Unexpectedly, the proliferation activity of c‐Kit+ HSPCs was only up‐regulated in the spleen, but not in the bone marrow, after Rg1 treatment in CY‐treated mice. We also found that a fraction of c‐Kit+/CD45+ HSPCs was simultaneously increased in the circulation after Rg1 treatment. Interestingly, the effects of Rg1 on the elevation of HSPCs in bone marrow and in the peripheral blood were suppressed in CY‐treated splenectomized mice. These results demonstrated that Rg1 improves myelosuppression induced by CY through its action on the proliferation of HSPCs in EMH of the spleen and migration of HSPCs from the spleen to the bone marrow.
Buprenorphine‐elicited alteration of adenylate cyclase activity in human embryonic kidney 293 cells coexpressing κ‐, μ‐opioid and nociceptin receptors
Authors: Wang Pei‐Chen , Ho Ing‐Kang , Lee Cynthia Wei‐Sheng 
Published: July 2015

AbstractBuprenorphine, a maintenance drug for heroin addicts, exerts its pharmacological function via κ‐ (KOP), μ‐opioid (MOP) and nociceptin/opioid receptor‐like 1 (NOP) receptors. Previously, we investigated its effects in an in vitro model expressing human MOP and NOP receptors individually or simultaneously (MOP, NOP, and MOP+NOP) in human embryonic kidney 293 cells. Here, we expanded this cell model by expressing human KOP, MOP and NOP receptors individually or simultaneously (KOP, KOP+MOP, KOP+NOP and KOP+MOP+NOP). Radioligand binding with tritium‐labelled diprenorphine confirmed the expression of KOP receptors. Immunoblotting and immunocytochemistry indicated that the expressed KOP, MOP and NOP receptors are N‐linked glycoproteins and colocalized in cytoplasmic compartments. Acute application of the opioid receptor agonists— U‐69593, DAMGO and nociceptin— inhibited adenylate cyclase (AC) activity in cells expressing KOP, MOP and NOP receptors respectively. Buprenorphine, when applied acutely, inhibited AC activity to ~90% in cells expressing KOP+MOP+NOP receptors. Chronic exposure to buprenorphine induced concentration‐dependent AC superactivation in cells expressing KOP+NOP receptors, and the level of this superactivation was even higher in KOP+MOP+NOP‐expressing cells. Our study demonstrated that MOP receptor could enhance AC regulation in the presence of coexpressed KOP and NOP receptors, and NOP receptor is essential for concentration‐dependent AC superactivation elicited by chronic buprenorphine exposure.
Role of exosomes and microvesicles in hypoxia‐associated tumour development and cardiovascular disease
Authors: Belting M. , Christianson H. C. 
Published: July 2015

AbstractExosomes and microvesicles, collectively referred to as extracellular vesicles (EVs), can transfer complex biological information and induce a diverse signalling response in recipient cells with potential relevance in a wide array of pathological conditions. Tissue hypoxia constitutes a stress‐associated phenotype that is central to the malignant state of aggressive tumours as well as to ischaemic tissue in cardiovascular disorders. The adaptive response to hypoxic stress is largely dependent on intercellular communication in which EVs, and cellular exchange of EV cargo molecules, have recently been implicated. The results of numerous studies indicate that hypoxia‐dependent shaping of the molecular profile of EVs may mediate the biological response to hypoxia. EVs have been shown to induce tumour angiogenesis and hypercoagulation as well as tissue remodelling and protective effects in ischaemic cardiovascular conditions. Recent findings report increased levels of circulating EVs in patients with hypoxia‐associated disorders such as myocardial infarction, stroke and pre‐eclampsia, indicating a role of EVs as biomarkers in these pathophysiological states. Here, we discuss the intriguing role of EVs in tumour development and cardiovascular disease, focusing on the paracrine transfer of the hypoxic response to neighbouring cells and to distant cells at the systemic level, with wide implications for biomarker discovery and therapeutic intervention.
Examining gender specificity of sexual response with concurrent thermography and plethysmography
Authors: Huberman Jackie S. , Chivers Meredith L. 
Published: July 2015

AbstractMen's genital responses are significantly greater to sexual stimuli of their preferred gender compared to their nonpreferred gender (gender‐specific), whereas androphilic (i.e., sexually attracted to men) women's genital responses are similar to sexual stimuli depicting either women or men (gender‐nonspecific). This gendered pattern of genital response has only been demonstrated using vaginal photoplethysmography (VPP) in women and primarily penile plethysmography (PPG) in men. These measures assess different aspects of genital vasocongestion, thereby limiting comparisons between genders. Thermography is a newer sexual psychophysiology methodology that measures genital vasocongestion via temperature change and is better suited to assess sexual response between genders because the dependent measure, change in genital temperature, is similar for women and men. Further, previous studies have assessed gender specificity of sexual response across relatively short sexual stimuli, allowing only the examination of initial phases of sexual response. We examined gender specificity of sexual arousal by measuring women's and men's genital responses to lengthier stimuli with concurrent thermography and VPP/PPG. Gynephilic men (i.e., sexually attracted to women; n = 27) and androphilic women (n = 28) viewed 10‐min films depicting men masturbating, women masturbating, and a nonsexual film, and reported feelings of sexual arousal while genital responses were assessed. Across measures, men's sexual responses were gender‐specific and women's responses were gender‐nonspecific, indicating that the gender difference in gender specificity of arousal is robust to methodology and stimulus duration. These findings replicate previous research, extend knowledge of gendered sexual response, and highlight the utility of multimethod approaches in sexual psychophysiology.
Competing Cultural Narratives: Gender and the Representation of US K–12 Teachers in Contemporary School Reform Policies
Authors: Kerstetter Katie 
Published: July 2015

AbstractCultural narratives about the proper scope and focus of teaching are embedded in contemporary school reform policies. This review examines literature related to two competing cultural narratives about US primary and secondary teachers: that “good teachers” are autonomous saviors, defined by their abilities to act independently and against great odds to improve academic outcomes for low‐income and minority students, and that “good teachers” are disempowered technicians who follow the guidance of externally‐recognized experts in their efforts to reduce educational inequalities. A review of literature critiquing these narratives finds that scholars have often analyzed these narratives using theoretical frameworks associated with race, class, and/or neoliberalism. This review examines what historians of education and feminist scholars can contribute to a critical analysis of the representation of US teachers in political speech and popular culture. It demonstrates that gender, as part of an intersectional approach, is important to understanding how White middle‐class women teachers can be positioned simultaneously as “autonomous saviors” and as “disempowered technicians” and how these narratives influence the professional status and autonomy associated with the work of teaching.
Prevention of stillbirth
Authors: Smith Gordon CS 
Published: July 2015

Key content

Most of the variability in stillbirth risk is not due to maternal risk factors, therefore modifying maternal risk factors or screening women using maternal risk factors to assess risk has limited potential impact.

The primary intervention that prevents stillbirth is delivery.

The overall risk of perinatal death is lowest at 39 weeks of gestation, and induction of labour at term does not increase a woman's risk of emergency caesarean section.

The most promising approach to screening low risk women for stillbirth risk may be to improve identification of small‐for‐gestational‐age infants; however, there is an absence of high quality evidence around the optimal approach for achieving this goal.

Learning objectives

To understand the relationship between maternal risk factors, obstetric complications and fetal size in relation to stillbirth risk.

To understand the approach to fetal assessment and elective delivery as methods to prevent stillbirth.

Ethical issues

Screening for stillbirth risk has the potential to do good by preventing deaths. However, if programmes of screening and intervention are developed, many more women may be harmed due to high false positive rates.
Influence of age on respiratory modulation of muscle sympathetic nerve activity, blood pressure and baroreflex function in humans
Authors: Shantsila Alena , McIntyre David B. , Lip Gregory Y. H. , Fadel Paul J. , Paton Julian F. R. , Pickering Anthony E. , Fisher James P. 
Published: July 2015

New Findings

What is the central question of this study?
Does ageing influence the respiratory‐related bursting of muscle sympathetic nerve activity (MSNA) and the association between the rhythmic fluctuations in MSNA and blood pressure (Traube–Hering waves) that occur with respiration?

What is the main finding and its importance?
Despite the age‐related elevation in MSNA, the cyclical inhibition of MSNA during respiration is similar between young and older individuals. Furthermore, central respiratory–sympathetic coupling plays a role in the generation of Traube–Hering waves in both young and older humans.

Healthy ageing and alterations in respiratory–sympathetic coupling have been independently linked with heightened sympathetic neural vasoconstrictor activity. We investigated how age influences the respiratory‐related modulation of muscle sympathetic nerve activity (MSNA) and the association between the rhythmic fluctuations in MSNA and blood pressure that occur with respiration (Traube–Hering waves; THW). Ten young (22 ± 2 years; mean ± SD) and 10 older healthy men (58 ± 6 years) were studied while resting supine and breathing spontaneously. MSNA, blood pressure and respiration were recorded simultaneously. Resting values were ascertained and respiratory cycle‐triggered averaging of MSNA and blood pressure measurements performed. The MSNA burst incidence was higher in older individuals [22.7 ± 9.2 versus 42.2 ± 13.7 bursts (100 heart beats)−1, P < 0.05], and was reduced to a similar extent in the inspiratory to postinspiratory period in young and older subjects (by ∼25% compared with mid‐ to late expiration). A similar attenuation of MSNA burst frequency (in bursts per minute), amplitude and total activity (burst frequency × mean burst amplitude) was also observed in the inspiratory to postinspiratory period in both groups. A significant positive correlation between respiratory‐related MSNA and the magnitude of Traube–Hering waves was observed in all young (100%) and most older subjects (80%). These data suggest that the strength of the cyclical inhibition of MSNA during respiration is similar between young and older individuals; thus, alterations in respiratory–sympathetic coupling appear not to contribute to the age‐related elevation in MSNA. Furthermore, central respiratory–sympathetic coupling plays a role in the generation of Traube–Hering waves in both healthy young and older humans.
Radiolysis of Supercritical Water at 400°C: A Sensitivity Study of the Density Dependence of the Yield of Hydrated Electrons on the (eaq−+eaq−) Reaction Rate Constant
Authors: Sanguanmith Sunuchakan , Meesungnoen Jintana , Guzonas David A. , Stuart Craig R. , Jay-Gerin Jean-Paul 
Published: July 2015

The temperature dependence of the rate constant (k) of the bimolecular reaction of two hydrated electrons (eaq−) measured in alkaline water exhibits an abrupt drop between 150°C and 200°C; above 250°C, it is too small to be measured reliably. Although this result is well established, the applicability of this sudden drop in k(eaq−+eaq−)) above ∼150°C to neutral or slightly acidic solution, as recommended by some authors, still remains uncertain. In fact, the recent work suggested that in near-neutral water the abrupt change in k above ∼150°C does not occur and that k should increase, rather than decrease, at temperatures greater than 150°C with roughly the same Arrhenius dependence of the data below 150°C. In view of this uncertainty of k, Monte Carlo simulations were used in this study to examine the sensitivity of the density dependence of the yield of eaq− in the low–linear energy transfer (LET) radiolysis of supercritical water (H2O) at 400°C on variations in the temperature dependence of k. Two different values of the eaq− self-reaction rate constant at 400°C were used: one was based on the temperature dependence of k above 150°C as measured in alkaline water (4.2×108  M−1 s−1), and the other was based on an Arrhenius extrapolation of the values below 150°C (2.5×1011  M−1 s−1). In both cases, the density dependences of our calculated eaq− yields at ∼60  ps and 1 ns were found to compare fairly well with the available picosecond pulse radiolysis experimental data (for D2O) for the entire water density range studied (∼0.15–0.6  g/cm3). Only a small effect of k on the variation of G(eaq−)) as a function of density at 60 ps and 1 ns could be observed. In conclusion, our present calculations did not allow us to unambiguously confirm (or deny) the applicability of the predicted sudden drop of k(eaq−+eaq−) at ∼150°C in near-neutral water.
NS5A Domain 1 and Polyprotein Cleavage Kinetics Are Critical for Induction of Double-Membrane Vesicles Associated with Hepatitis C Virus Replication
Authors: Romero-Brey Inés , Berger Carola , Kallis Stephanie , Kolovou Androniki , Paul David , Lohmann Volker , Bartenschlager Ralf 
Published: July 2015

ABSTRACT

Induction of membrane rearrangements in the cytoplasm of infected cells is a hallmark of positive-strand RNA viruses. These altered membranes serve as scaffolds for the assembly of viral replication factories (RFs). We have recently shown that hepatitis C virus (HCV) infection induces endoplasmic reticulum-derived double-membrane vesicles (DMVs) representing the major constituent of the RF within the infected cell. RF formation requires the concerted action of nonstructural action of nonstructural protein (NS)3, -4A, protein (NS)3 -4A, -4B, -5A, and -5B. Although the sole expression of NS5A is sufficient to induce DMV formation, its efficiency is very low. In this study, we dissected the determinants within NS5A responsible for DMV formation and found that RNA-binding domain 1 (D1) and the amino-terminal membrane anchor are indispensable for this process. In contrast, deletion of NS5A D2 or D3 did not affect DMV formation but disrupted RNA replication and virus assembly, respectively. To identify
cis
- and
trans
-acting factors of DMV formation, we established a
trans
cleavage assay. We found that induction of DMVs requires full-length NS3, whereas a helicase-lacking mutant was unable to trigger DMV formation in spite of efficient polyprotein cleavage. Importantly, a mutation accelerating cleavage kinetics at the NS4B-5A site diminished DMV formation, while the insertion of an internal ribosome entry site mimicking constitutive cleavage at this boundary completely abolished this process. These results identify key determinants governing the biogenesis of the HCV RF with possible implications for our understanding of how RFs are formed in other positive-strand RNA viruses.

IMPORTANCE
Like all positive-strand RNA viruses, hepatitis C virus (HCV) extensively reorganizes intracellular membranes to allow efficient RNA replication. Double-membrane vesicles (DMVs) that putatively represent sites of HCV RNA amplification are induced by the concerted action of viral and cellular factors. However, the contribution of individual proteins to this process remains poorly understood. Here we identify determinants in the HCV replicase that are required for DMV biogenesis. Major contributors to this process are domain 1 of nonstructural protein 5A and the helicase domain of nonstructural protein 3. In addition, efficient DMV induction depends on
cis
cleavage of the viral polyprotein, as well as tightly regulated cleavage kinetics. These results identify key determinants governing the biogenesis of the HCV replication factory with possible implications for our understanding of how this central compartment is formed in other positive-strand RNA viruses.
TORC1 Regulates Developmental Responses to Nitrogen Stress via Regulation of the GATA Transcription Factor Gaf1
Authors: Laor Dana , Cohen Adiel , Kupiec Martin , Weisman Ronit 
Published: July 2015

ABSTRACT

The TOR (target of rapamycin [sirolimus]) is a universally conserved kinase that couples nutrient availability to cell growth. TOR complex 1 (TORC1) in
Schizosaccharomyces pombe
positively regulates growth in response to nitrogen availability while suppressing cellular responses to nitrogen stress. Here we report the identification of the GATA transcription factor Gaf1 as a positive regulator of the nitrogen stress-induced gene
isp7
+
, via three canonical GATA motifs. We show that under nitrogen-rich conditions, TORC1 positively regulates the phosphorylation and cytoplasmic retention of Gaf1 via the PP2A-like phosphatase Ppe1. Under nitrogen stress conditions when TORC1 is inactivated, Gaf1 becomes dephosphorylated and enters the nucleus. Gaf1 was recently shown to negatively regulate the transcription induction of
ste11
+
, a major regulator of sexual development. Our findings support a model of a two-faceted role of Gaf1 during nitrogen stress. Gaf1 positively regulates genes that are induced early in the response to nitrogen stress, while inhibiting later responses, such as sexual development. Taking these results together, we identify Gaf1 as a novel target for TORC1 signaling and a step-like mechanism to modulate the nitrogen stress response.

IMPORTANCE
TOR complex 1 (TORC1) is an evolutionary conserved protein complex that positively regulates growth and proliferation, while inhibiting starvation responses. In fission yeast, the activity of TORC1 is downregulated in response to nitrogen starvation, and cells reprogram their transcriptional profile and prepare for sexual development. We identify Gaf1, a GATA-like transcription factor that regulates transcription and sexual development in response to starvation, as a downstream target for TORC1 signaling. Under nitrogen-rich conditions, TORC1 positively regulates the phosphorylation and cytoplasmic retention of Gaf1 via the PP2A-like phosphatase Ppe1. Under nitrogen stress conditions when TORC1 is inactivated, Gaf1 becomes dephosphorylated and enters the nucleus. Budding yeast TORC1 regulates GATA transcription factors via the phosphatase Sit4, a structural homologue of Ppe1. Thus, the TORC1-GATA transcription module appears to be conserved in evolution and may also be found in higher eukaryotes.