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Gap junction

Jian-Feng Wu, Jie Ji, Shu-Ying Dong, Bei-Bei Li, Mei-Ling Yu, Dan-Dan Wu, Liang Tao, Xu-Hui Tong
Chemotherapeutic drug-induced apoptosis is enhanced by gap junction intercellular communication (GJIC) in a variety of tumor cells. Oxaliplatin and gefitinib are the most widely used chemotherapeutic drugs. However, the synergistic influence remains unknown in testicular cancer chemotherapy. The aim of the present study was to investigate the apoptosis induced by oxaliplatin combined with gefitinib and the potential mechanisms in I-10 testicular cancer cells. The results showed that gefitinib significantly enhanced oxaliplatin-induced apoptosis...
October 11, 2016: Oncology Reports
Zhao-Wei Zou, Hai-Jin Chen, Jin-Long Yu, Zong-Hai Huang, Shun Fang, Xiao-Hua Lin
Chemotherapy is one of the most commonly used therapeutic strategies for metastatic colon cancer. However, the development of resistance to chemotherapeutic agents limits their application in clinical use. The underlying mechanisms of this resistance development require further elucidation. The current study investigated the effects of connexin43 (Cx43) gap junctions on 5‑fluorouracil (5‑FU), oxaliplatin and irinotecan in colon cancer cells. Three different methods were used to manipulate Cx43 gap junction function: i) Cell culture at different densities; ii) pretreatment with a Cx43 specific inhibitor or enhancer; and iii) Cx43 gene knock‑down...
October 6, 2016: Molecular Medicine Reports
Li-Jie Wang, Wei-Dong Liu, Liang Zhang, Ke-Tao Ma, Lei Zhao, Wen-Yan Shi, Wen-Wen Zhang, Ying-Zi Wang, Li Li, Jun-Qiang Si
Niflumic acid (NFA) is a novel gap junction (GJ) inhibitor. The aim of the present study was to investigate the effect of NFA on GJ communication and the expression of connexin (Cx) in vascular smooth muscle cells (VSMCs) of mesenteric arterioles of spontaneously hypertensive rats (SHR). Whole‑cell patch clamp recording demonstrated that NFA at 1x10‑4 M significantly inhibited the inward current and its effect was reversible. The time for charging and discharging of cell membrane capacitance (Cinput) reduced from 9...
September 26, 2016: Molecular Medicine Reports
H Mike Kim, Colin R Andrews, Evan P Roush, Gregory I Pace, Gregory S Lewis
BACKGROUND: Double-strand lateral ulnar collateral ligament (LUCL) reconstruction is an effective treatment for posterolateral rotatory instability (PLRI) of the elbow, but anatomic landmarks for ulnar tunnel placement are often difficult to identify intraoperatively, which potentially can result in a nonanatomic LUCL reconstruction. This study investigated the effect of ulnar tunnel location on joint stability in double-strand LUCL reconstruction. METHODS: PLRI was artificially created in 7 cadaveric elbows, and double-strand LUCL reconstruction was performed...
October 10, 2016: Journal of Shoulder and Elbow Surgery
Prateek Mahalwar, Ajeet Pratap Singh, Andrey Fadeev, Christiane Nüsslein-Volhard, Uwe Irion
The conspicuous striped coloration of zebrafish is produced by cell-cell interactions among three different types of chromatophores: black melanophores, orange/yellow xanthophores and silvery/blue iridophores. During color pattern formation xanthophores undergo dramatic cell shape transitions and acquire different densities, leading to compact and orange xanthophores at high density in the light stripes, and stellate, faintly pigmented xanthophores at low density in the dark stripes. Here, we investigate the mechanistic basis of these cell behaviors in vivo, and show that local, heterotypic interactions with dense iridophores regulate xanthophore cell shape transition and density...
October 14, 2016: Biology Open
Taizen Nakase, Tatsuya Ishikawa, Hajime Miyata
Fragility of atheromatous plaque in the internal carotid artery can be a risk of brain infarction. The activation of macrophages by oxidative stress and the vulnerability of vascular endothelial cells have been reported to participate in the fragility of atheromatous plaque. Therefore, from the view point of prevention of brain infarction, we investigated the pathological factors which may influence the stabilization of atheromatous plaque. Patients undertaking carotid endoarterectomy (CEA) were continuously screened...
October 13, 2016: Neuropathology: Official Journal of the Japanese Society of Neuropathology
Hongmei Liu, Hisashi Kondo, Takahisa Ohno
Utilizing first-principles theory, we demonstrate that half-metallicity can be realized in a junction composed of non-magnetic armchair graphene nanoribbon (AGNR) and ferromagnetic Ni electrodes. The half-metallic property originates from the AGNR energy gap of the up spin located at the Fermi energy, while large electronic states are generated for the down spin. By altering the interlayer distance and the contact area, namely, the strength of AGNR-Ni interaction, the efficiency of the spin filter becomes lower, since the energy gap moves away from the Fermi energy with the variation of charge transfer intensity...
December 2016: Nanoscale Research Letters
Daniel Torralba, Francesc Baixauli, Francisco Sánchez-Madrid
Mitochondria regulate multiple cell processes, including calcium signaling, apoptosis and cell metabolism. Mitochondria contain their own circular genome encoding selected subunits of the oxidative phosphorylation complexes. Recent findings reveal that, in addition to being maternally inherited, mitochondria can traverse cell boundaries and thus be horizontally transferred between cells. Although, the physiological relevance of this phenomenon is still under debate, mitochondria uptake rescues mitochondrial respiration defects in recipient cells and regulates signaling, proliferation or chemotherapy resistance in vitro and in vivo...
2016: Frontiers in Cell and Developmental Biology
Javier Cervera, Salvador Meseguer, Salvador Mafe
The single cell-centred approach emphasises ion channels as specific proteins that determine individual properties, disregarding their contribution to multicellular outcomes. We simulate the interplay between genetic and bioelectrical signals in non-excitable cells from the local single-cell level to the long range multicellular ensemble. The single-cell genetic regulation is based on mean-field kinetic equations involving the mRNA and protein concentrations. The transcription rate factor is assumed to depend on the absolute value of the cell potential, which is dictated by the voltage-gated cell ion channels and the intercellular gap junctions...
October 12, 2016: Scientific Reports
Onur Kilic, David Pamies, Emily Lavell, Paula Schiapparelli, Yun Feng, Thomas Hartung, Anna Bal-Price, Helena T Hogberg, Alfredo Quinones-Hinojosa, Hugo Guerrero-Cazares, Andre Levchenko
Migration of neural progenitors in the complex tissue environment of the central nervous system is not well understood. Progress in this area has the potential to drive breakthroughs in neuroregenerative therapies, brain cancer treatments, and neurodevelopmental studies. To a large extent, advances have been limited due to a lack of controlled environments recapitulating characteristics of the central nervous system milieu. Reductionist cell culture models are frequently too simplistic, and physiologically more relevant approaches such as ex vivo brain slices or in situ experiments provide little control and make information extraction difficult...
October 18, 2016: Lab on a Chip
Nicholas A Early, John J Elias, Steven B Lippitt, Danielle E Filipkowski, Robert A Pedowitz, William J Ciccone
BACKGROUND: This in vitro study evaluated the biomechanical benefit of adding spanning sutures to single-row rotator cuff repair. METHODS: Mechanical testing was performed to evaluate 9 pairs of cadaveric shoulders with complete rotator cuff repairs, with a single-row technique used on one side and the suture spanning technique on the other. The spanning technique included sutures from 2 lateral anchors securing tendon near the musculotendinous junction, spanning the same anchor placement from single-row repair...
October 5, 2016: Journal of Shoulder and Elbow Surgery
Rosario Gajardo-Gómez, Valeria C Labra, Juan A Orellana
Under physiological conditions, microglia adopt a resting phenotype associated with the production of anti-inflammatory and neurotrophic factors. In response to a wide variety of insults, these cells shift to an activated phenotype that is necessary for the proper restoration of brain homeostasis. However, when the intensity of a threat is relatively high, microglial activation worsens the progression of damage rather than providing protection, with potentially significant consequences for neuronal survival...
2016: Frontiers in Molecular Neuroscience
Shaowen Chen, Zheng Han, Mirza M Elahi, K M Masum Habib, Lei Wang, Bo Wen, Yuanda Gao, Takashi Taniguchi, Kenji Watanabe, James Hone, Avik W Ghosh, Cory R Dean
Electrons transmitted across a ballistic semiconductor junction are expected to undergo refraction, analogous to light rays across an optical boundary. In graphene, the linear dispersion and zero-gap band structure admit highly transparent p-n junctions by simple electrostatic gating. Here, we employ transverse magnetic focusing to probe the propagation of carriers across an electrostatically defined graphene junction. We find agreement with the predicted Snell's law for electrons, including the observation of both positive and negative refraction...
September 30, 2016: Science
Lauw J Klaassen, Wim de Graaff, Jorrit B Van Asselt, Jan Klooster, Maarten Kamermans
The functional and morphological connectivity between various horizontal cell (HC) types (H1, H2, H3 and H4), and photoreceptors was studied in zebrafish retina. Since HCs are strongly coupled by gap-junctions and feedback from HCs to photoreceptors strongly depends on connexin (Cx) hemichannels we characterized the various HC Cxs (Cx52.6, Cx52.7, Cx52.9 and Cx55.5) in Xenopus oocytes. All Cxs formed hemichannels which were conducting at physiological membrane potentials. The Cx hemichannels differed in kinetic properties and voltage dependence, allowing for specific tuning of the coupling of HCs and the feedback signal from HCs to cones...
October 5, 2016: Journal of Neurophysiology
Monika Rak, Anna Ochałek, Ewa Bielecka, Joanna Latasiewicz, Katarzyna Gawarecka, Jolanta Sroka, Jarosław Czyż, Katarzyna Piwowarczyk, Marek Masnyk, Marek Chmielewski, Tadeusz Chojnacki, Ewa Swiezewska, Zbigniew Madeja
BACKGROUND: One of the major challenges limiting development of gene therapy is absence of efficient and safe gene carriers. Among the non-viral gene delivery methods, lipofection is considered as one of the most promising. In this study a set of cationic polyprenyl derivatives (trimethylpolyprenylammonium iodides - PTAI) with different lengths of polyprenyl chains (from 7, 8 and 11 to 15 isoprene units) was suggested as a component of efficient DNA vehicles. METHODS: Optimization studies were conducted for PTAI in combination with co-lipid DOPE (dioleoylphosphatidylethanolamine) on DU145 human prostate cancer cells using: size and zeta potential measurements, confocal microscopy, fluorescein diacetate/ethidium bromide test, cell counting, time-lapse monitoring of cell movement, gap junctional intracellular coupling analysis, antimicrobial activity assay, red blood cell hemolysis test...
October 5, 2016: Journal of Gene Medicine
Tania Martins-Marques, Maria Joao Pinho, Monica Zuzarte, Carla Oliveira, Paulo Pereira, Joost P G Sluijter, Celia Gomes, Henrique Girao
Extracellular vesicles (EVs) are major conveyors of biological information, mediating local and systemic cell-to-cell communication under physiological and pathological conditions. These endogenous vesicles have been recognized as prominent drug delivery vehicles of several therapeutic cargoes, including doxorubicin (dox), presenting major advantages over the classical approaches. Although dox is one of the most effective anti-tumour agents in the clinical practice, its use is very often hindered by its consequent dramatic cardiotoxicity...
2016: Journal of Extracellular Vesicles
A F Dulhunty, L Wei-LaPierre, M G Casarotto, N A Beard
The core skeletal muscle ryanodine receptor (RyR1) calcium release complex extends through three compartments of the muscle fibre, linking the extracellular environment through the cytoplasmic junctional gap to the lumen of the internal sarcoplasmic reticulum (SR) calcium store. The protein complex is essential for skeletal excitation-contraction (EC-) coupling and skeletal muscle function. Its importance is highlighted by perinatal death if any one of the EC-coupling components are missing and by myopathies associated with mutation of any of the proteins...
October 1, 2016: Clinical and Experimental Pharmacology & Physiology
Patrycja Orlowska-Feuer, Jagoda S Jeczmien-Lazur, Hanna J Szkudlarek, Marian H Lewandowski
A subpopulation of olivary pretectal nucleus (OPN) neurons fire action potentials in a rhythmic manner with an eruption of activity occurring approximately every two minutes. These infra-slow oscillations depend critically on functional retinal input and are subject to modulation by light. Interestingly, the activity of photoreceptors is necessary for the emergence of the rhythm and while classic photoreceptors (rods and cones) are necessary in darkness and dim light, melanopsin photoreceptors are indispensable in bright light...
September 28, 2016: Neuroscience
Leif Hertz, Ye Chen
Initial clearance of extracellular K(+) ([K(+)]o) following neuronal excitation occurs by astrocytic uptake, because elevated [K(+)]o activates astrocytic but not neuronal Na(+),K(+)-ATPases. Subsequently, astrocytic K(+) is re-released via Kir4.1 channels after distribution in the astrocytic functional syncytium via gap junctions. The dispersal ensures widespread release, preventing renewed [K(+)]o increase and allowing neuronal Na(+),K(+)-ATPase-mediated re-uptake. Na(+),K(+)-ATPase operation creates extracellular hypertonicity and cell shrinkage which is reversed by the astrocytic cotransporter NKCC1...
September 28, 2016: Neuroscience and Biobehavioral Reviews
R Frisenda, H S J van der Zant
We have investigated charge transport in single-molecule junctions using gold nanoelectrodes at room and cryogenic (10 K) temperatures. A statistical analysis of the low-bias conductance, measured during the stretching of the molecular junctions, shows that the most probable single-molecule conductance is insensitive to the temperature as expected for off-resonant coherent transport. Low-temperature current-voltage measurements show that these junction conformations have a smooth tunnelinglike shape. While separating the electrodes further we find that, in about one-fourth of the cases, the junction switches in an abrupt way to a configuration with I-V characteristics exhibiting a gap around zero bias and resonances at finite bias...
September 16, 2016: Physical Review Letters
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