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Simultaneous Application (simultaneous + application)

Distribution by Scientific Domains

Life Sciences	62%
Medical Sciences	25%

Selected Abstracts

Effect of Simultaneous Application of Stressful Culture Conditions on Specific Productivity and Heterogeneity of Erythropoietin in Chinese Hamster Ovary Cells

BIOTECHNOLOGY PROGRESS, Issue 4 2004
Sung Kwan Yoon
A single stressful culture condition induced by hypoosmotic stress (210 mOsm kg,1), low culture temperature (32 °C), or NaBu addition (1 mM) resulted in a 1.8- to 2.2-fold enhancement of specific erythropoietin (EPO) productivity (qEPO) of recombinant Chinese hamster ovary (rCHO) cells compared to normal culture condition (37 °C and 310 mOsm kg,1). Simultaneous application of these stressful conditions further enhanced qEPO up to approximately 5-fold. However, the quality of EPO was affected by stressful culture conditions. The proportion of acidic isoforms of EPO under a single stressful condition was 2.8,13.8% lower than that under normal culture condition. Simultaneous application of the stressful conditions further decreased the portion of acidic isoforms but not significantly. Despite 5-fold enhancement of qEPO, the portion of acidic isoforms under the simultaneous application of stressful culture conditions was 12.9,21.6% lower than that under normal culture condition. Taken together, these results suggest the potential of simultaneous application of different stressful culture conditions to the production phase of two-stage culture, where cell growth and production phases are separated, for improved EPO production. [source]

Cholesterol-promoted synaptogenesis requires the conversion of cholesterol to estradiol in the hippocampus

HIPPOCAMPUS, Issue 8 2009
Lars Fester
Abstract Cholesterol of glial origin promotes synaptogenesis (Mauch et al., (2001) Science 294:1354,1357). Because in the hippocampus local estradiol synthesis is essential for synaptogenesis, we addressed the question of whether cholesterol-promoted synapse formation results from the function of cholesterol as a precursor of estradiol synthesis in this brain area. To this end, we treated hippocampal cultures with cholesterol, estradiol, or with letrozole, a potent aromatase inhibitor. Cholesterol increased neuronal estradiol release into the medium, the number of spine synapses in hippocampal slice cultures, and immunoreactivity of synaptic proteins in dispersed cultures. Simultaneous application of cholesterol and letrozole or blockade of estrogen receptors by ICI 182 780 abolished cholesterol-induced synapse formation. As a further approach, we inhibited the access of cholesterol to the first enzyme of steroidogenesis by knock-down of steroidogenic acute regulatory protein, the rate-limiting step in steroidogenesis. A rescue of reduced synaptic protein expression in transfected cells was achieved by estradiol but not by cholesterol. Our data indicate that in the hippocampus cholesterol-promoted synapse formation requires the conversion of cholesterol to estradiol. © 2009 Wiley-Liss, Inc. [source]

Mechanisms of non-steroid anti-inflammatory drugs action on ASICs expressed in hippocampal interneurons

JOURNAL OF NEUROCHEMISTRY, Issue 1 2008
Natalia A. Dorofeeva
Abstract The inhibitory action of non-steroid anti-inflammatory drugs was investigated on acid-sensing ionic channels (ASIC) in isolated hippocampal interneurons and on recombinant ASICs expressed in Chinese hamster ovary (CHO) cells. Diclofenac and ibuprofen inhibited proton-induced currents in hippocampal interneurons (IC50 were 622 ± 34 ,M and 3.42 ± 0.50 mM, respectively). This non-competitive effect was fast and fully reversible for both drugs. Aspirin and salicylic acid at 500 ,M were ineffective. Diclofenac and ibuprofen decreased the amplitude of proton-evoked currents and slowed the rates of current decay with a good correlation between these effects. Simultaneous application of acid solution and diclofenac was required for its inhibitory effect. Unlike amiloride, the action of diclofenac was voltage-independent and no competition between two drugs was found. Analysis of the action of diclofenac and ibuprofen on activation and desensitization of ASICs showed that diclofenac but not ibuprofen shifted the steady-state desensitization curve to more alkaline pH values. The reason for this shift was slowing down the recovery from desensitization of ASICs. Thus, diclofenac may serve as a neuroprotective agent during pathological conditions associated with acidification. [source]

Galanin modulates vagally induced contractions in the mouse oesophagus

NEUROGASTROENTEROLOGY & MOTILITY, Issue 2 2009
A. Boudaka
Abstract, Nitrergic myenteric neurons co-innervating motor endplates were previously shown to inhibit vagally induced contractions of striated muscle in the rodent oesophagus. Immunohistochemical demonstration of putative co-transmitters, e.g. galanin, in enteric neurons prompted us to study a possible role of galanin in modulating vagally mediated contractions in an in vitro vagus nerve-oesophagus preparation of the mouse. Galanin (1,16) (1,100 nmol L,1), in the presence of the peptidase inhibitor, phenanthroline monohydrate, inhibited vagally induced contractions in a concentration-dependent manner (control: 100%; galanin 1 nmol L,1: 95.6 ± 1.6%; galanin 10 nmol L,1: 57.3 ± 6.5%; galanin 100 nmol L,1: 31.2 ± 8.1%, n = 5). The non-selective galanin receptor antagonist, galantide (100 nmol L,1), blocked the inhibitory effect of galanin (10 nmol L,1) while the selective non-galanin receptor 1 and galanin receptor 3 antagonists, M871 (1 ,mol L,1) and SNAP37889 (100 nmol L,1), respectively, and the nitric oxide synthase inhibitor, NG-nitro- l -arginine methyl ester (l - NAME) (200 ,mol L,1), failed to affect this galanin-induced response. Simultaneous application of galantide (100 nmol L,1) and l -NAME (200 ,mol L,1) significantly reduced the inhibitory effect of capsaicin (30 ,mol L,1) on vagally induced contractions when compared with its effect in the presence of l -NAME alone or in combination with the selective galanin receptor 2 or 3 antagonists. An inhibitory effect of piperine on vagally induced contractions was reduced neither by galantide nor by l -NAME. Immunohistochemistry revealed galanin immunoreactive myenteric neurons and nerve fibres intermingling with cholinergic vagal terminals at motor endplates. These data suggest that galanin from co-innervating enteric neurons co-operates with nitric oxide in modulating vagally induced contractions in the mouse oesophagus. [source]

Role of heat treatment in childhood cancers: Distinct resistance profiles of solid tumor cell lines towards combined thermochemotherapy

PEDIATRIC BLOOD & CANCER, Issue 5 2005
Anette Debes PhD
Abstract Background Since information on the efficacy of hyperthermia in combination with chemotherapy on pediatric tumors is limited, we performed a systematic analysis on the synergistic effects of a combined application of heat and chemotherapy on 20 tumor cell lines derived from patients with neuroblastomas, Ewing tumors, germ cell tumors (GCT), and osteosarcomas. Methods Cisplatin (cDDP), a cross-linking agent, and etoposide (VP-16), a topoisomerase II inhibitor, were examined either alone or in combination with heat (42°C, 43°C) by using the XTT-assay 1. Results Our data demonstrate that heat stress at 43°C for 1 hr, but not at 42°C, leads to a notable cytotoxic effect on the different tumor cells. The comparison of mean survival fractions reveals values between 62% for neuroblastoma cells and 76% for Ewing tumor cells. Analyzing the sensitivity to chemotherapy alone, our results show that cDDP (5 ,g/ml) reduces cell growth to 47% in Ewing tumor cells, to 61% in neuroblastoma cells, to 75% in GCT cells, and to 76% in osteosarcoma cells. Treatment with VP-16 (10 ,g/ml) decreases cell survival to mean values between 58% (neuroblastomas) and 77% (osteosarcomas). Simultaneous application of heat and chemotherapy enhances synergistically cDDP cytotoxicity in all tumor types tested, whereas the efficacy of VP-16 is only slightly influenced by additional application of hyperthermia. The cytotoxicity of cDDP (5 ,g/ml) can be increased by a factor of between 1.5 and 2.5 at 42°C and from 2.6 to 14.0 at 43°C. Furthermore, the results show that the sensitivity to heat (43°C) as well as the sensitivity to chemotherapy and combined thermochemotherapy varies considerably between cell lines of the same tumor group. Conclusions Simultaneous application of hyperthermia synergistically enhances the cytotoxicity of the alkylating agent cDDP, but not of the topoisomerase II inhibitor VP-16, in a defined spectrum of cell lines from different pediatric tumor entities. © 2005 Wiley-Liss, Inc. [source]

Effect of Simultaneous Application of Stressful Culture Conditions on Specific Productivity and Heterogeneity of Erythropoietin in Chinese Hamster Ovary Cells

Dopamine modulation of the In vivo acetylcholine response in the Drosophila mushroom body

DEVELOPMENTAL NEUROBIOLOGY, Issue 11 2009
Vitold Tsydzik
Abstract Olfactory sensory information in Drosophila is transmitted through antennal lobe projections to Mushroom Body neurons (Kenyon cells) by means of cholinergic synapses. Application of acetylcholine (ACh) and odors produce significant increases in intracellular calcium ([Ca2+]i) in these neurons. Behavioral studies show that Kenyon cell activity is modulated by dopaminergic inputs and this modulation is thought to be the basis for an olfactory conditioned response. However, quantitative assessment of the synaptic inputs to Kenyon cells is currently lacking. To assess neuronal activity under in vivo conditions, we have used the endogenously-expressed camgaroo reporter to measure [Ca2+]i in these neurons. We report here the dose-response relationship of Kenyon cells for ACh and dopamine (DA). Importantly, we also show that simultaneous application of ACh and DA results in a significant decrease in the response to ACh alone. In addition, we show inhibition of the ACh response by cyclic adenosine monophosphate. This is the first quantitative assessment of the effects of these two important transmitters in this system, and it provides an important basis for future analysis of the cellular mechanisms of this well established model for associative olfactory learning. © 2009 Wiley Periodicals, Inc. Develop Neurobiol, 2009 [source]

Quantized Double-Layer Charging of Iron Oxide Nanoparticles on a-Si:H Controlled by Charged Defects in a-Si:H

ELECTROANALYSIS, Issue 12 2007
Martin Weis
Abstract Sequential single-electron charging of iron oxide nanoparticles encapsulated in oleic acid/oleyl amine envelope and deposited by the Langmuir-Blodgett technique onto Pt electrode covered with undoped hydrogenated amorphous silicon film (a-Si:H) is reported. Quantized double-layer charging of nanoparticles is detected by cyclic voltammetry as current peaks and the charging effect can be switched on/off by the excess of negative/positive charged defect states in the a-Si:H layer. The particular charge states in a-Si:H are created by the simultaneous application of a suitable bias voltage and illumination before the measurement. [source]

Temperature-Dependent Solid-State Reactions With and Without Kirkendall Effect in Al2O3/ZnO, Fe2O3/ZnO, and CoXOY/ZnO Oxide Thin Film Systems,

ADVANCED ENGINEERING MATERIALS, Issue 6 2010
Andriy Zolotaryov
Temperature-dependent solid-state reactions and the occurrence of the Kirkendall effect are studied in thin film oxide systems applying optical reflection microscopy, X-ray reflectivity, (scanning) transmission electron microscopy, grazing-incidence X-ray diffraction measurements, and SQUID magnetometry. The efficiency of the simultaneous application of different analytical methods for the precise selection and investigation of the most interesting samples is demonstrated first on the example of the Al2O3/ZnO system, for which the spinel formation after a solid-state reaction and the formation of Kirkendall voids were already reported. The demonstrated methodology is then applied to study Fe2O3/ZnO and CoXOY/ZnO film pairs. The investigations clearly demonstrate the temperature-driven formation of a ferromagnetic spinel by a solid state reaction involving the Kirkendall effect in the Fe2O3/ZnO system, already after an annealing at 600,°C for 1,h. We also report on the solid state reaction in the CoXOY/ZnO system after annealing at 700,°C for 1,h, however without the Kirkendall effect and without any evidence of ferromagnetism of the final state. [source]

AMPA/kainate and NMDA-like glutamate receptors at the chromatophore neuromuscular junction of the squid: role in synaptic transmission and skin patterning

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2003
Pedro A. Lima
Abstract Glutamate receptor types were examined at the chromatophore synapses of the squids Alloteuthis subulata and Loligo vulgaris, where nerve-induced muscle contraction causes chromatophore expansion. Immunoblotting with antibody raised against a squid AMPA receptor (sGluR) demonstrated that AMPA/kainate receptors are present in squid skin. Application of l -glutamate evoked chromatophore muscle contractions in both ventral and dorsal skins, while NMDA was only active on a subpopulation of dorsal chromatophores. In dorsal skin, neurotransmission was partly blocked by either AMPA/kainate receptor antagonists (CNQX and DNQX) or NMDA receptor antagonists (AP-5 and MK-801) or completely blocked by simultaneous application of both classes of antagonists. In isolated muscle fibres, ionophoretic application of l -glutamate evoked fast inward CNQX- and DNQX-sensitive currents with reversal potentials around +14 mV and a high conductance to Na+. In fibres from dorsal skin only, a slower outward glutamate-sensitive current appeared at positive holding potentials. At negative potentials, currents were potentiated by glycine or by removing external Mg2+ and were blocked by AP-5 and MK-801. Glutamate caused a fast, followed by a slow, transient increase in cytoplasmic Ca2+. The slow component was increased in amplitude and duration by glycine or by lowering external Mg2+ and decreased by AP-5 and MK-801. In cells from ventral skin, no ,NMDA-like responses' were detected. Thus, while AMPA/kainate receptors mediated fast excitatory synaptic transmission and rapid colour change over the whole skin, activation of both AMPA/kainate and NMDA-like receptors in a subpopulation of dorsal chromatophores prolonged the postsynaptically evoked Ca2+ elevation causing temporally extended colour displays with behavioural significance. [source]

In depolarized and glucose-deprived neurons, Na+ influx reverses plasmalemmal K+ -dependent and K+ -independent Na+/Ca2+ exchangers and contributes to NMDA excitotoxicity

JOURNAL OF NEUROCHEMISTRY, Issue 6 2002
Aneta Czy
Abstract Cerebellar granule cells (CGCs) express K+ -dependent (NCKX) and K+ -independent (NCX) plasmalemmal Na+/Ca2+ exchangers which, under plasma membrane-depolarizing conditions and high cytosolic [Na+], may reverse and mediate potentially toxic Ca2+ influx. To examine this possibility, we inhibited NCX or NCKX with KB-R7943 or K+ -free medium, respectively, and studied how gramicidin affects cytosolic [Ca2+] and 45Ca2+ accumulation. Gramicidin forms pores permeable to alkali cations but not Ca2+. Therefore, gramicidin-induced Ca2+ influx is indirect; it results from fluxes of monovalent cations. In the presence of Na+, but not Li+ or Cs+, gramicidin induced Ca2+ influx that was inhibited by simultaneous application of KB-R7943 and K+ -free medium. The data indicate that gramicidin-induced Na+ influx reverses NCX and NCKX. To test the role of NCX and/or NCKX in excitotoxicity, we studied how NMDA affects the viability of glucose-deprived and depolarized CGCs. To assure depolarization of the plasma membrane, we inhibited Na+,K+ -ATPase with ouabain. Although inhibition of NCX or NCKX reversal failed to significantly limit 45Ca2+ accumulation and excitotoxicity, simultaneously inhibiting NCX and NCKX reversal was neuroprotective and significantly decreased NMDA-induced 45Ca2+ accumulation. Our data suggest that NMDA-induced Na+ influx reverses NCX and NCKX and leads to the death of depolarized and glucose-deprived neurons. [source]

Competing Presynaptic and Postsynaptic Effects of Ethanol on Cerebellar Purkinje Neurons

ALCOHOLISM, Issue 8 2006
Zhen Ming
Background: Ethanol has actions on cerebellar Purkinje neurons that can result either in a net excitation or in inhibition of neuronal activity. The present study examines the interplay of presynaptic and postsynaptic mechanisms to determine the net effect of ethanol on the neuronal firing rate of cerebellar Purkinje neurons. Methods: Whole-cell voltage-clamp recording of miniature inhibitory postsynaptic currents (mIPSCs) from Purkinje neurons in cerebellar slices was used to examine the effect of ethanol on presynapticsynaptic release of , -aminobutyric acid (GABA) and glutamate. Extracellular recording was used to examine the net action of both presynaptic and postsynaptic effects of ethanol on the firing rate of Purkinje neurons. Results: Under whole-cell voltage clamp, the frequency of bicuculline-sensitive miniature postsynaptic currents (mIPSCs) was increased dose-dependently by 25, 50, and 100 mM ethanol without any change in amplitude or decay time. Despite this evidence of increased release of GABA by ethanol, application of 50 mM ethanol caused an increase in firing in some neurons and a decrease in firing in others with a nonrandom distribution. When both glutamatergic and GABAergic influences were removed by simultaneous application of 6-cyano-7-nitroquinoxaline-2,3-dione and picrotoxin, respectively, ethanol caused only an increase in firing rate. Conclusions: These data are consistent with a dual action of ethanol on cerebellar Purkinje neuron activity. Specifically, ethanol acts presynaptically to increase inhibition by release of GABA, while simultaneously acting postsynaptically to increase intrinsic excitatory drive. [source]

How do UV Photomorphogenic Responses Confer Water Stress Tolerance?,,

PHOTOCHEMISTRY & PHOTOBIOLOGY, Issue 6 2003
Dennis C. Gitz
ABSTRACT Although ultraviolet-B (UV-B) radiation is potentially harmful, it is an important component of terrestrial radiation to which plants have been exposed since invading land. Since then, plants have evolved mechanisms to avoid and repair UV radiation damage; therefore, it is not surprising that photomorphogenic responses to UV-B are often assumed to be adaptations to harmful radiation. This presupposes that the function of the observed responses is to prevent UV damage. It has been hypothesized that, as with blue light, UV-B provides a signal important for normal plant development and might be perceived within developing plants through nondestructive processes, perhaps through UV-specific signal perception mechanisms. UV signal perception can lead to photomorphogenic responses that may confer adaptive advantages under conditions associated with high-light environments, such as water stress. Plant responses to UV radiation in this regard include changes in leaf area, leaf thickness, stomatal density, photosynthetic pigment production and altered stem elongation and branching patterns. Such responses may lead to altered transpiration rates and water-use efficiencies. For example, we found that the cumulative effect of ambient UV-B radiation upon stomatal density and conductance can lead to altered water-use efficiencies. In field settings, UV might more properly be viewed as a photomorphogenic signal than as a stressor. Hence, it might be insufficient to attempt to fully evaluate the adaptive roles of plant responses to UV-B cues upon stress tolerance by the simultaneous application of UV and drought stress during development. We propose that rather than examining a plant's response to combinations of stressors one might also examine how a plant's response to UV induces tolerance to subsequently applied stresses. [source]

Basolateral anion transport mechanisms underlying fluid secretion by mouse, rat and guinea-pig pancreatic ducts

THE JOURNAL OF PHYSIOLOGY, Issue 2 2004
M. Paz Fernández-Salazar
Fluid secretion by interlobular pancreatic ducts was determined by using video microscopy to measure the rate of swelling of isolated duct segments that had sealed following overnight culture. The aim was to compare the HCO3, requirement for secretin-evoked secretion in mouse, rat and guinea-pig pancreas. In mouse and rat ducts, fluid secretion could be evoked by 10 nm secretin and 5 ,m forskolin in the absence of extracellular HCO3,. In guinea-pig ducts, however, fluid secretion was totally dependent on HCO3,. Forskolin-stimulated fluid secretion by mouse and rat ducts in the absence of HCO3, was dependent on extracellular Cl, and was completely inhibited by bumetanide (30 ,m). It was therefore probably mediated by a basolateral Na+,K+,2Cl, cotransporter. In the presence of HCO3,, forskolin-stimulated fluid secretion was reduced ,40% by bumetanide, ,50% by inhibitors of basolateral HCO3, uptake (3 ,m EIPA and 500 ,m H2DIDS), and was totally abolished by simultaneous application of all three inhibitors. We conclude that the driving force for secretin-evoked fluid secretion by mouse and rat ducts is provided by parallel basolateral mechanisms: Na+,H+ exchange and Na+,HCO3, cotransport mediating HCO3, uptake, and Na+,K+,2Cl, cotransport mediating Cl, uptake. The absence or inactivity of the Cl, uptake pathway in the guinea-pig pancreatic ducts may help to account for the much higher concentrations of HCO3, secreted in this species. [source]

Effect of Simultaneous Application of Stressful Culture Conditions on Specific Productivity and Heterogeneity of Erythropoietin in Chinese Hamster Ovary Cells

Simultaneous sodium lauryl sulphate testing improves the diagnostic validity of allergic patch tests.

BRITISH JOURNAL OF DERMATOLOGY, Issue 4 2005
Results from a prospective multicentre study of the German Contact Dermatitis Research Group (Deutsche Kontaktallergie-Gruppe
Summary Background, There is evidence that a higher skin susceptibility may induce nonspecific erythematous or weak positive reactions to contact allergens in patch testing. Objectives, To evaluate whether simultaneous application of sodium lauryl sulphate (SLS) along with diagnostic patch tests with contact allergens can provide information regarding skin irritability which may help to discriminate allergic from nonspecific irritant reactions to contact allergens. Methods, Between July 2001 and June 2003, this prospective study collected patch test data of 5971 patients from 19 centres in Germany and Austria in the Information Network of Departments of Dermatology (IVDK). In addition to contact allergens (standard series and eight known ,problematic' allergens with a low reaction index and a high positivity ratio: 1,3-diphenylguanidine, amerchol L-101, benzalkonium chloride, benzoyl peroxide, cocamidopropyl betaine, octyl gallate, phenyl mercuric acetate and propylene glycol), patches with SLS 0·5% and 0·25% aq. were applied. Reactions to the allergens and to SLS were analysed at the IVDK data centre. The association between an erythematous or positive reaction to a certain allergen and an irritant reaction to SLS was assessed with logistic regression analysis, at the same time controlling for the influence of age and sex. Results, Of the 29 allergens of the standard series, 23 and 21 gave a higher percentage of nonspecific erythematous reactions in patients with an irritant reaction to 0·25% and 0·5% SLS, respectively, in comparison with SLS-negative patients. All eight ,problematic' allergens gave an increased percentage of nonspecific erythematous reactions. Similarly, 22 and 21 allergens of the standard series gave a higher percentage of positive allergic reactions in patients with an irritant reaction to 0·25% and 0·5% SLS, respectively, and seven of the eight ,problematic' allergens gave a higher percentage of positive allergic rections (exception: octyl gallate). For most allergens, the markers of skin reaction (reaction index and positivity ratio) were worse in SLS-positive patients. Differences were more pronounced when testing with SLS 0·25% than with SLS 0·5%. Conclusions, Because there is a convincing association between skin irritability (evaluated by SLS test) and the degree of skin reaction to contact allergens, the SLS test may help in deciding whether a doubtful erythematous or weakly ,positive' skin reaction should be interpreted as allergic or irritant. [source]