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Action potential

Adrian N Beyer, Jeremy O Richardson, Peter J Knowles, Judith Rommel, Stuart C Althorpe
The instanton method obtains approximate tunneling rates from the minimum-action path (known as the instanton) linking reactants to the products at a given temperature. An efficient way to find the instanton is to search for saddle-points on the ring-polymer potential surface, which is obtained by expressing the quantum Boltzmann operator as a discrete path-integral. Here we report a practical implementation of this ring-polymer form of instanton theory into the Molpro electronic-structure package, which allows the rates to be computed on-the-fly, without the need for a fitted analytic potential-energy surface...
October 24, 2016: Journal of Physical Chemistry Letters
Talita B Gontijo, Rossimiriam P de Freitas, Guilherme F de Lima, Lucas C D de Rezende, Leandro F Pedrosa, Thaissa L Silva, Marilia O F Goulart, Bruno C Cavalcanti, Claudia Pessoa, Marina P Bruno, José R Corrêa, Flavio S Emery, Eufrânio N da Silva Júnior
For the first time, a fluorescent lapachone-based BODIPY was synthesised and characterised by NMR and mass spectrometry. Computational and electrochemical aspects, as well as cytotoxic activity and subcellular localisation, were studied. Confocal microscopy experiments indicated that the probe was a specific mitochondria-staining agent. These in-detail analyses were useful in understanding the cytotoxic effects and mechanism of action of this novel hybrid compound. This molecule constitutes a promising prototype owing to its potential biological activities and the new strategies aimed at mechanistic investigations in cells and in vivo, and opens up an interesting avenue of research...
October 24, 2016: Chemical Communications: Chem Comm
Mariangela Marrelli, Filomena Conforti, Fabrizio Araniti, Giancarlo A Statti
Obesity is one of the greatest public health problems. This complex condition has reached epidemic proportions in many parts of the world, and it constitutes a risk factor for several chronic disorders, such as hypertension, cardiovascular diseases and type 2 diabetes. In the last few decades, several studies dealt with the potential effects of natural products as new safe and effective tools for body weight control. Saponins are naturally-occurring surface-active glycosides, mainly produced by plants, whose structure consists of a sugar moiety linked to a hydrophobic aglycone (a steroid or a triterpene)...
October 20, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
Aleksandra Bocian, Małgorzata Urbanik, Konrad Hus, Andrzej Łyskowski, Vladimír Petrilla, Zuzana Andrejčáková, Monika Petrillová, Jaroslav Legath
Snake venom is a rich source of peptides and proteins with a wide range of actions. Many of the venom components are currently being tested for their usefulness in the treatment of many diseases ranging from neurological and cardiovascular to cancer. It is also important to constantly search for new proteins and peptides with properties not yet described. The venom of Vipera berus berus has hemolytic, proteolytic and cytotoxic properties, but its exact composition and the factors responsible for these properties are not known...
October 19, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
M Cebová, M Košútová, O Pecháňová
Gasotransmitters represent a subfamily of the endogenous gaseous signaling molecules that include nitric oxide (NO), carbon monoxide (CO), and hydrogen sulphide (H(2)S). These particular gases share many common features in their production and function, but they fulfill their physiological tasks in unique ways that differ from those of classical signaling molecules found in tissues and organs. These gasotransmitters may antagonize or potentiate each other's cellular effects at the level of their production, their downstream molecular targets and their direct interactions...
October 24, 2016: Physiological Research
Beata Jackowska-Zduniak, Urszula Forys
A proposed model consisting of two coupled models (Hodgkin-Huxley and Yanagihara-Noma-Irisawa model) is considered as a description of the heart's action potential. System of ordinary differential equations is used to recreate pathological behaviour in the conducting heart's system such as double fire and the most common tachycardia: atrioventricular nodal reentrant tachycardia (AVNRT). Part of the population has an abnormal accessory pathways: fast and slow (Fujiki, 2008). These pathways in the atrioventricular node (AV node) are anatomical and functional contributions of supraventricular tachycardia...
December 1, 2016: Mathematical Biosciences and Engineering: MBE
Hyun Jin Yang, Michael Trenary, Maki Kawai, Yousoo Kim
In contrast to conventional spectroscopic studies of adsorbates at high coverage that provide only spatially averaged information, we have characterized the laterally confined shuttling dynamics of a single molecule under the influence of intermolecular interactions by vibrational spectroscopy using a scanning tunneling microscope. The bridge sites on Pt(111) are only occupied by a CO molecule that is surrounded by four other CO molecules at on-top sites. The bridge-site CO undergoes laterally confined shuttling toward an adjacent on-top site to transiently occupy a metastable site, which is slightly displaced from the center of an on-top site through repulsive interaction with adjacent on-top CO molecules...
October 24, 2016: Journal of Physical Chemistry Letters
T Jean M Arseneau-Robar, Eliane Müller, Anouk L Taucher, Carel P van Schaik, Erik P Willems
Males in a number of group-living species fight in intergroup conflicts to defend access to food resources, a seemingly paradoxical behaviour, given that this resource does not usually limit male fitness directly. We investigated the mechanism(s) driving apparent male food defence in wild vervet monkeys (Chlorocebus aethiops pygerythrus) by testing the effect that female resource access, and female audience size and activity had on the response of focal males during simulated intergroup encounters. Males do not appear to defend food to increase the reproductive success of female group members because their response was not influenced by the presence of provisioning boxes that only females could access...
October 24, 2016: Scientific Reports
Viviana Guadagni, Chiara Cerri, Ilaria Piano, Elena Novelli, Claudia Gargini, Carla Fiorentini, Matteo Caleo, Enrica Strettoi
Retinitis pigmentosa (RP) comprises a group of inherited pathologies characterized by progressive photoreceptor degeneration. In rodent models of RP, expression of defective genes and retinal degeneration usually manifest during the first weeks of postnatal life, making it difficult to distinguish consequences of primary genetic defects from abnormalities in retinal development. Moreover, mouse eyes are small and not always adequate to test pharmacological and surgical treatments. An inducible paradigm of retinal degeneration potentially extensible to large animals is therefore desirable...
October 24, 2016: Scientific Reports
Zhi Li, Mengying Zhang, Xueqin Li, Jinming Lu, Liang Xu
Objective To investigate the effect of adipose-derived mesenchymal stem cells (ADSCs) on glomerular mesangial cell proliferation via Wnt/β-catenin pathway. Methods The rat glomerular mesangial cells (HBZY-1) were incubated in conditioned ADSC medium. Cell cycle was analyzed with flow cytometry; the proliferation rate of HBZY-1 and the expression levels of relative genes and proteins of Wnt signaling pathway were measured using RNA interference, quantitative real-time PCR and Western blotting, respectively...
November 2016: Xi Bao Yu Fen Zi Mian Yi Xue za Zhi, Chinese Journal of Cellular and Molecular Immunology
Subha Rastogi, Madan Mohan Pandey, Aks Rawat
BACKGROUND: Dietary factors play a key role in the development as well as prevention of certain human diseases, including cardiovascular diseases. Currently there has been an increase in global interest to identify medicinal plants that are pharmacologically effective and have low or no side effects for use in preventive medicine. Culinary herbs and spices are an important part of human nutrition in all the cultures of the world. There is a growing amount of literature concerning the potential benefits of these herbs and spices from a health perspective especially in conferring protection against cardiovascular diseases...
October 21, 2016: Current Pharmaceutical Design
Himanshi Kapoor, Nalini Yadav, Madhu Chopra, Sushil Chandra Mahapatra, Veena Agrawal
Glioblastoma has been reckoned as the prime cause of death due to brain tumours, being most invasive and lethal. Available treatment options, i.e. surgery, radiotherapy, chemotherapy and targeted therapies are not effective in improving prognosis, so an alternate therapy is insistent. Plant based drugs are efficient due to their synergistic action, multi-targeted approach and least side effects. Present investigation reports the strong anti-tumorous potential of Nardostachys jatamansi rhizome extract (NJRE) on U87 MG glioblastoma cells...
October 19, 2016: Current Cancer Drug Targets
Hem Singh, Atish Prakash, A N Kalia, Abu Bakar Abdul Majeed
Previously explored combination therapies mostly involved the use of bioactive molecules. It is believed that herbal compounds containing multiple plant products have synergistic hepatoprotective effects and could enhance the desired actions. To investigate the combination of ethanolic fruits extract of Solanum xanthocarpum (SX) and Juniperus communis (JC) against Paracetamol (PCM) and Azithromycin (AZM) induced liver toxicity in rats. Liver toxicity was induced by combine oral administration of PCM (250 mg/kg) and AZM (200 mg/kg) for 7 days in Wistar rats...
October 2016: Journal of Traditional and Complementary Medicine
Michelle Maclean, John G Anderson, Scott J MacGregor, Tracy White, Chintamani D Atreya
Bacterial contamination of injectable stored biological fluids such as blood plasma and platelet concentrates preserved in plasma at room temperature is a major health risk. Current pathogen reduction technologies (PRT) rely on the use of chemicals and/or ultraviolet light, which affects product quality and can be associated with adverse events in recipients. 405 nm violet-blue light is antibacterial without the use of photosensitizers and can be applied at levels safe for human exposure, making it of potential interest for decontamination of biological fluids such as plasma...
2016: Journal of Blood Transfusion
Uri Maoz, Gideon Yaffe
A defendant is criminally responsible for his action only if he is shown to have engaged in a guilty act-actus reus (eg for larceny, voluntarily taking someone else's property without permission)-while possessing a guilty mind-mens rea (eg knowing that he had taken someone else's property without permission, intending not to return it)-and lacking affirmative defenses (eg the insanity defense or self-defense). We therefore first review neuroscientific studies that bear on the nature of voluntary action, and so could, potentially, tell us something of importance about the actus reus of crimes...
April 2016: Journal of Law and the Biosciences
Alex Fogli Iseppe, Angela Pignatelli, Ottorino Belluzzi
Within the olfactory bulb (OB), periglomerular (PG) cells consist of various types of interneurons, generally classified by their chemical properties such as neurotransmitter and calcium binding proteins. Calretinin (CR) characterizes morphologically and functionally the more numerous and one of the less known subpopulation of PG cells in the OB. Using of transgenic mice expressing eGFP under the CR promoter, we have tried to obtain the first functional characterization of these cells. Electrophysiological recordings were made in these cells using the patch-clamp technique in thin slices...
2016: Frontiers in Cellular Neuroscience
Itsuro Kazama
By simply adding a high concentration of calcium solution to the surface of the bullfrog heart, we reproduced electrocardiogram (ECG) abnormalities representing those observed in hypercalcemia, such as Osborn waves and shortening of the QT interval. The rise in extracellular calcium concentration may have activated the outward potassium currents during phase 3 of the action potential, and thus decreased its duration. In addition to the known decrease in the duration of phase 2, such changes in phase 3 were also likely to contribute to the shortening of the QT interval...
October 22, 2016: Journal of Veterinary Medical Science
Alfred Maroyi
ETHNOPHARMACOLOGICAL RELEVANCE: Crinum macowanii is a deciduous bulbous plant which grows in east, central and southern Africa. Crinum macowanii has been used as herbal medicine by the indigenous people of east and southern Africa has for several centuries. The bulb, leaves and roots of C. macowanii are reported to possess diverse medicinal properties and used to treat or manage various human and animal diseases and ailments throughout its distributional range. Crinum macowanii is used traditionally as a remedy for boils, diarrhoea, fever, inflammation, respiratory system problems, skin rashes, tuberculosis, wounds and urinary tract problems...
October 20, 2016: Journal of Ethnopharmacology
Chatchai Muanprasat, Varanuj Chatsudthipong
Chitosan oligosaccharide (COS) is an oligomer of β-(1➔4)-linked D-glucosamine. COS can be prepared from the deacetylation and hydrolysis of chitin, which is commonly found in the exoskeletons of arthropods and insects and the cell walls of fungi. COS is water soluble, non-cytotoxic, readily absorbed through the intestine and mainly excreted in the urine. Of particular importance, COS and its derivatives have been demonstrated to possess several biological activities including anti-inflammation, immunostimulation, anti-tumor, anti-obesity, anti-hypertension, anti-Alzheimer's disease, tissue regeneration promotion, drug and DNA delivery enhancement, anti-microbial, anti-oxidation and calcium-absorption enhancement...
October 20, 2016: Pharmacology & Therapeutics
Ceyda Acilan, Zelal Adiguzel, Buse Cevatemre, Didem Karakas, Engin Ulukaya, Nádia Ribeiro, Isabel Correia, João Costa Pessoa
BACKGROUND: To overcome the hurdles of cisplatin, majorly its toxicity and resistance, there has been extensive search for alternative anti-cancer metal-based compounds. Here, three Cu(II)-complexes, Cu(Sal-Gly)(phen), Cu(Sal-Gly)(pheamine), Cu(Sal-Gly)(phepoxy) are characterized for their interaction with DNA, cytotoxicity and mechanism of action. METHODS: The binding ability of the complexes to Calf-Thymus DNA was evaluated by competition fluorescence studies with thiazole-orange, UV-Vis and circular-dichroism spectroscopic titrations...
October 20, 2016: Biochimica et Biophysica Acta
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